From a3ffe6f874cdd7686013202f76962c8c7d8d74af Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 26 Sep 2016 09:30:15 -0700
Subject: [PATCH 001/224] Parse, bind and check spread types and elements

---
 src/compiler/binder.ts               |  12 +-
 src/compiler/checker.ts              | 407 ++++++++++++++++++++++-----
 src/compiler/diagnosticMessages.json |  12 +
 src/compiler/parser.ts               |  29 +-
 src/compiler/types.ts                |  92 +++---
 src/compiler/utilities.ts            |   1 +
 src/harness/harness.ts               |   2 +-
 src/services/findAllReferences.ts    |   6 +-
 8 files changed, 447 insertions(+), 114 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 49434e80abab4..d3217fd70a850 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -1825,8 +1825,9 @@ namespace ts {
                 case SyntaxKind.EnumMember:
                     return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.EnumMember, SymbolFlags.EnumMemberExcludes);
 
+                case SyntaxKind.SpreadElement:
                 case SyntaxKind.JsxSpreadAttribute:
-                    emitFlags |= NodeFlags.HasJsxSpreadAttributes;
+                    emitFlags |= NodeFlags.HasSpreadAttribute;
                     return;
 
                 case SyntaxKind.CallSignature:
@@ -2956,8 +2957,9 @@ namespace ts {
                 }
                 break;
 
+            case SyntaxKind.SpreadElement:
             case SyntaxKind.SpreadElementExpression:
-                // This node is ES6 syntax, but is handled by a containing node.
+                // This node is ES6 or ES future syntax, but is handled by a containing node.
                 transformFlags |= TransformFlags.ContainsSpreadElementExpression;
                 break;
 
@@ -2996,6 +2998,12 @@ namespace ts {
                     transformFlags |= TransformFlags.ContainsLexicalThis;
                 }
 
+                if (subtreeFlags & TransformFlags.ContainsSpreadElementExpression) {
+                    // If an ObjectLiteralExpression contains a spread element, then it
+                    // is an ES experimental node.
+                    transformFlags |= TransformFlags.AssertExperimental;
+                }
+
                 break;
 
             case SyntaxKind.ArrayLiteralExpression:
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 51550ef873fc5..3578aeb5e4bb9 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -112,6 +112,7 @@ namespace ts {
         const tupleTypes: GenericType[] = [];
         const unionTypes = createMap<UnionType>();
         const intersectionTypes = createMap<IntersectionType>();
+        const spreadTypes = createMap<SpreadType>();
         const stringLiteralTypes = createMap<LiteralType>();
         const numericLiteralTypes = createMap<LiteralType>();
 
@@ -2185,7 +2186,10 @@ namespace ts {
                         writeSymbolTypeReference(type.aliasSymbol, typeArguments, 0, typeArguments ? typeArguments.length : 0, nextFlags);
                     }
                     else if (type.flags & TypeFlags.UnionOrIntersection) {
-                        writeUnionOrIntersectionType(<UnionOrIntersectionType>type, nextFlags);
+                        writeUnionOrIntersectionType(<TypeOperatorType>type, nextFlags);
+                    }
+                    else if (type.flags & TypeFlags.Spread) {
+                        writeSpreadType(<SpreadType>type, nextFlags);
                     }
                     else if (type.flags & TypeFlags.Anonymous) {
                         writeAnonymousType(<ObjectType>type, nextFlags);
@@ -2279,7 +2283,7 @@ namespace ts {
                     }
                 }
 
-                function writeUnionOrIntersectionType(type: UnionOrIntersectionType, flags: TypeFormatFlags) {
+                function writeUnionOrIntersectionType(type: TypeOperatorType, flags: TypeFormatFlags) {
                     if (flags & TypeFormatFlags.InElementType) {
                         writePunctuation(writer, SyntaxKind.OpenParenToken);
                     }
@@ -2294,6 +2298,36 @@ namespace ts {
                     }
                 }
 
+                function writeSpreadType(type: SpreadType, flags: TypeFormatFlags) {
+                    writePunctuation(writer, SyntaxKind.OpenBraceToken);
+                    writer.writeLine();
+                    writer.increaseIndent();
+                    let printFollowingPunctuation = false;
+                    for (const t of type.types) {
+                        if (printFollowingPunctuation) {
+                            writePunctuation(writer, SyntaxKind.SemicolonToken);
+                            writer.writeLine();
+                        }
+                        if (t.isDeclaredProperty) {
+                            const saveInObjectTypeLiteral = inObjectTypeLiteral;
+                            inObjectTypeLiteral = true;
+                            writeObjectLiteralType(resolveStructuredTypeMembers(t));
+                            printFollowingPunctuation = false;
+                            inObjectTypeLiteral = saveInObjectTypeLiteral;
+                        }
+                        else {
+                            writePunctuation(writer, SyntaxKind.DotDotDotToken);
+                            writeType(t, TypeFormatFlags.None);
+                            printFollowingPunctuation = true;
+                        }
+                    }
+                    writer.decreaseIndent();
+                    if (printFollowingPunctuation) {
+                        writeSpace(writer);
+                    }
+                    writePunctuation(writer, SyntaxKind.CloseBraceToken);
+                }
+
                 function writeAnonymousType(type: ObjectType, flags: TypeFormatFlags) {
                     const symbol = type.symbol;
                     if (symbol) {
@@ -2436,6 +2470,13 @@ namespace ts {
                     writePunctuation(writer, SyntaxKind.OpenBraceToken);
                     writer.writeLine();
                     writer.increaseIndent();
+                    writeObjectLiteralType(resolved);
+                    writer.decreaseIndent();
+                    writePunctuation(writer, SyntaxKind.CloseBraceToken);
+                    inObjectTypeLiteral = saveInObjectTypeLiteral;
+                }
+
+                function writeObjectLiteralType(resolved: ResolvedType) {
                     for (const signature of resolved.callSignatures) {
                         buildSignatureDisplay(signature, writer, enclosingDeclaration, globalFlagsToPass, /*kind*/ undefined, symbolStack);
                         writePunctuation(writer, SyntaxKind.SemicolonToken);
@@ -2468,11 +2509,8 @@ namespace ts {
                             writer.writeLine();
                         }
                     }
-                    writer.decreaseIndent();
-                    writePunctuation(writer, SyntaxKind.CloseBraceToken);
-                    inObjectTypeLiteral = saveInObjectTypeLiteral;
                 }
-            }
+           }
 
             function buildTypeParameterDisplayFromSymbol(symbol: Symbol, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags) {
                 const targetSymbol = getTargetSymbol(symbol);
@@ -2981,7 +3019,11 @@ namespace ts {
                 // present (aka the tuple element property). This call also checks that the parentType is in
                 // fact an iterable or array (depending on target language).
                 const elementType = checkIteratedTypeOrElementType(parentType, pattern, /*allowStringInput*/ false);
-                if (!declaration.dotDotDotToken) {
+                if (declaration.dotDotDotToken) {
+                    // Rest element has an array type with the same element type as the parent type
+                    type = createArrayType(elementType);
+                }
+                else {
                     // Use specific property type when parent is a tuple or numeric index type when parent is an array
                     const propName = "" + indexOf(pattern.elements, declaration);
                     type = isTupleLikeType(parentType)
@@ -2997,10 +3039,6 @@ namespace ts {
                         return unknownType;
                     }
                 }
-                else {
-                    // Rest element has an array type with the same element type as the parent type
-                    type = createArrayType(elementType);
-                }
             }
             // In strict null checking mode, if a default value of a non-undefined type is specified, remove
             // undefined from the final type.
@@ -4266,6 +4304,22 @@ namespace ts {
             setObjectTypeMembers(type, emptySymbols, callSignatures, constructSignatures, stringIndexInfo, numberIndexInfo);
         }
 
+        function resolveSpreadTypeMembers(type: SpreadType) {
+            // The members and properties collections are empty for spread types. To get all properties of an
+            // spread type use getPropertiesOfType (only the language service uses this).
+            let stringIndexInfo: IndexInfo = undefined;
+            let numberIndexInfo: IndexInfo = undefined;
+            for (let i = type.types.length - 1; i > -1; i--) {
+                const t = type.types[i];
+                stringIndexInfo = intersectIndexInfos(stringIndexInfo, getIndexInfoOfType(t, IndexKind.String));
+                numberIndexInfo = intersectIndexInfos(numberIndexInfo, getIndexInfoOfType(t, IndexKind.Number));
+                if (!t.symbol || !(t.symbol.flags & SymbolFlags.Optional)) {
+                    break;
+                }
+            }
+            setObjectTypeMembers(type, emptySymbols, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
+        }
+
         function resolveAnonymousTypeMembers(type: AnonymousType) {
             const symbol = type.symbol;
             if (type.target) {
@@ -4332,6 +4386,9 @@ namespace ts {
                 else if (type.flags & TypeFlags.Intersection) {
                     resolveIntersectionTypeMembers(<IntersectionType>type);
                 }
+                else if (type.flags & TypeFlags.Spread) {
+                    resolveSpreadTypeMembers(<SpreadType>type);
+                }
             }
             return <ResolvedType>type;
         }
@@ -4341,6 +4398,9 @@ namespace ts {
             if (type.flags & TypeFlags.ObjectType) {
                 return resolveStructuredTypeMembers(<ObjectType>type).properties;
             }
+            if (type.flags & TypeFlags.Spread) {
+                return getPropertiesOfType(type);
+            }
             return emptyArray;
         }
 
@@ -4356,10 +4416,11 @@ namespace ts {
             }
         }
 
-        function getPropertiesOfUnionOrIntersectionType(type: UnionOrIntersectionType): Symbol[] {
+        function getPropertiesOfUnionOrIntersectionOrSpreadType(type: TypeOperatorType): Symbol[] {
+            const getProperty = type.flags & TypeFlags.Spread ? getPropertyOfSpreadType : getPropertyOfUnionOrIntersectionType;
             for (const current of type.types) {
                 for (const prop of getPropertiesOfType(current)) {
-                    getPropertyOfUnionOrIntersectionType(type, prop.name);
+                    getProperty(type, prop.name);
                 }
                 // The properties of a union type are those that are present in all constituent types, so
                 // we only need to check the properties of the first type
@@ -4372,7 +4433,8 @@ namespace ts {
 
         function getPropertiesOfType(type: Type): Symbol[] {
             type = getApparentType(type);
-            return type.flags & TypeFlags.UnionOrIntersection ? getPropertiesOfUnionOrIntersectionType(<UnionType>type) : getPropertiesOfObjectType(type);
+            return type.flags & (TypeFlags.UnionOrIntersection | TypeFlags.Spread) ? getPropertiesOfUnionOrIntersectionOrSpreadType(<UnionType>type) :
+                getPropertiesOfObjectType(type);
         }
 
         /**
@@ -4398,7 +4460,7 @@ namespace ts {
         function getApparentType(type: Type): Type {
             if (type.flags & TypeFlags.TypeParameter) {
                 type = getApparentTypeOfTypeParameter(<TypeParameter>type);
-            }
+          }
             if (type.flags & TypeFlags.StringLike) {
                 type = globalStringType;
             }
@@ -4414,34 +4476,43 @@ namespace ts {
             return type;
         }
 
-        function createUnionOrIntersectionProperty(containingType: UnionOrIntersectionType, name: string): Symbol {
+        function createUnionOrIntersectionProperty(containingType: TypeOperatorType, name: string): Symbol {
             const types = containingType.types;
-            let props: Symbol[];
-            // Flags we want to propagate to the result if they exist in all source symbols
-            let commonFlags = (containingType.flags & TypeFlags.Intersection) ? SymbolFlags.Optional : SymbolFlags.None;
-            let isReadonly = false;
-            for (const current of types) {
-                const type = getApparentType(current);
-                if (type !== unknownType) {
-                    const prop = getPropertyOfType(type, name);
-                    if (prop && !(getDeclarationModifierFlagsFromSymbol(prop) & (ModifierFlags.Private | ModifierFlags.Protected))) {
-                        commonFlags &= prop.flags;
-                        if (!props) {
-                            props = [prop];
-                        }
-                        else if (!contains(props, prop)) {
-                            props.push(prop);
+            return createUnionOrIntersectionOrSpreadPropertySymbol(containingType, name, () => {
+                let props: Symbol[];
+                // Flags we want to propagate to the result if they exist in all source symbols
+                let commonFlags = (containingType.flags & TypeFlags.Intersection) ? SymbolFlags.Optional : SymbolFlags.None;
+                let isReadonly = false;
+                for (const current of types) {
+                    const type = getApparentType(current);
+                    if (type !== unknownType) {
+                        const prop = getPropertyOfType(type, name);
+                        if (prop && !(getDeclarationModifierFlagsFromSymbol(prop) & (ModifierFlags.Private | ModifierFlags.Protected))) {
+                            commonFlags &= prop.flags;
+                            if (!props) {
+                                props = [prop];
+                            }
+                            else if (!contains(props, prop)) {
+                                props.push(prop);
+                            }
+                            if (isReadonlySymbol(prop)) {
+                                isReadonly = true;
+                            }
                         }
-                        if (isReadonlySymbol(prop)) {
-                            isReadonly = true;
+                        else if (containingType.flags & TypeFlags.Union) {
+                            // A union type requires the property to be present in all constituent types
+                            return [undefined, false, 0];
                         }
                     }
-                    else if (containingType.flags & TypeFlags.Union) {
-                        // A union type requires the property to be present in all constituent types
-                        return undefined;
-                    }
                 }
-            }
+                return [props, isReadonly, commonFlags];
+            });
+        }
+
+        function createUnionOrIntersectionOrSpreadPropertySymbol(containingType: TypeOperatorType,
+                                                                 name: string,
+                                                                 symbolCreator: () => [Symbol[], boolean, SymbolFlags]) {
+            const [props, isReadonly, flags] = symbolCreator();
             if (!props) {
                 return undefined;
             }
@@ -4469,17 +4540,17 @@ namespace ts {
                 SymbolFlags.Property |
                 SymbolFlags.Transient |
                 SymbolFlags.SyntheticProperty |
-                commonFlags,
+                flags,
                 name);
             result.containingType = containingType;
             result.hasCommonType = hasCommonType;
             result.declarations = declarations;
             result.isReadonly = isReadonly;
-            result.type = containingType.flags & TypeFlags.Union ? getUnionType(propTypes) : getIntersectionType(propTypes);
+            result.type = containingType.flags & TypeFlags.Intersection ? getIntersectionType(propTypes) : getUnionType(propTypes);
             return result;
         }
 
-        function getPropertyOfUnionOrIntersectionType(type: UnionOrIntersectionType, name: string): Symbol {
+        function getPropertyOfUnionOrIntersectionType(type: TypeOperatorType, name: string): Symbol {
             const properties = type.resolvedProperties || (type.resolvedProperties = createMap<Symbol>());
             let property = properties[name];
             if (!property) {
@@ -4491,6 +4562,61 @@ namespace ts {
             return property;
         }
 
+        function createSpreadProperty(containingType: SpreadType, name: string): Symbol {
+            const types = containingType.types;
+            return createUnionOrIntersectionOrSpreadPropertySymbol(containingType, name, () => {
+                let props: Symbol[];
+                // Result is readonly if any source is readonly
+                let isReadonly = false;
+                // Result is optional if all sources are optional
+                let commonFlags = SymbolFlags.Optional;
+                for (let i = types.length - 1; i > -1; i--) {
+                    const type = getApparentType(types[i]);
+                    if (type !== unknownType) {
+                        const prop = getPropertyOfType(type, name);
+                        if (prop) {
+                            if (prop.flags & SymbolFlags.Method && !types[i].isDeclaredProperty ||
+                                prop.flags & SymbolFlags.SetAccessor && !(prop.flags & SymbolFlags.GetAccessor)) {
+                                // skip non-object-literal methods and set-only properties and keep looking
+                                continue;
+                            }
+                            if (!props) {
+                                props = [prop];
+                            }
+                            else if (!contains(props, prop)) {
+                                props.unshift(prop);
+                            }
+                            if (isReadonlySymbol(prop)) {
+                                isReadonly = true;
+                            }
+                            if (getDeclarationModifierFlagsFromSymbol(prop) & (ModifierFlags.Private | ModifierFlags.Protected)) {
+                                // return immediately because even if prop is optional, it would make the unioned spread property private
+                                return [undefined, false, 0];
+                            }
+                            if (!(prop.flags & SymbolFlags.Optional)) {
+                                // Reset extraFlags to None since we found a non-optional property
+                                commonFlags = SymbolFlags.None;
+                                break;
+                            }
+                        }
+                    }
+                }
+                return [props, isReadonly, commonFlags];
+            });
+        }
+
+        function getPropertyOfSpreadType(type: TypeOperatorType, name: string): Symbol {
+            const properties = type.resolvedProperties || (type.resolvedProperties = createMap<Symbol>());
+            let property = properties[name];
+            if (!property) {
+                property = createSpreadProperty(type as SpreadType, name);
+                if (property) {
+                    properties[name] = property;
+                }
+            }
+            return property;
+        }
+
         /**
          * Return the symbol for the property with the given name in the given type. Creates synthetic union properties when
          * necessary, maps primitive types and type parameters are to their apparent types, and augments with properties from
@@ -4516,7 +4642,10 @@ namespace ts {
                 return getPropertyOfObjectType(globalObjectType, name);
             }
             if (type.flags & TypeFlags.UnionOrIntersection) {
-                return getPropertyOfUnionOrIntersectionType(<UnionOrIntersectionType>type, name);
+                return getPropertyOfUnionOrIntersectionType(<TypeOperatorType>type, name);
+            }
+            if (type.flags & TypeFlags.Spread) {
+                return getPropertyOfSpreadType(<SpreadType>type, name);
             }
             return undefined;
         }
@@ -5538,8 +5667,44 @@ namespace ts {
         function getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node: Node, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
             const links = getNodeLinks(node);
             if (!links.resolvedType) {
-                // Deferred resolution of members is handled by resolveObjectTypeMembers
-                const type = createObjectType(TypeFlags.Anonymous, node.symbol);
+                const isSpread = (node.kind === SyntaxKind.TypeLiteral &&
+                                  find((node as TypeLiteralNode).members, elt => elt.kind === SyntaxKind.SpreadTypeElement));
+                let type: ObjectType;
+                if (isSpread) {
+                    let members: Map<Symbol>;
+                    const spreads: SpreadElementType[] = [];
+                    for (const member of (node as TypeLiteralNode).members) {
+                        if (member.kind === SyntaxKind.SpreadTypeElement) {
+                            if (members) {
+                                const t = createAnonymousType(undefined, members, emptyArray, emptyArray, undefined, undefined) as SpreadElementType;
+                                t.isDeclaredProperty = true;
+                                spreads.push(t);
+                                members = undefined;
+                            }
+                            spreads.push(getTypeFromTypeNode((member as SpreadTypeElement).type) as SpreadElementType);
+                        }
+                        else if (member.kind !== SyntaxKind.CallSignature && member.kind !== SyntaxKind.ConstructSignature) {
+                            // note that spread types don't include call and construct signatures
+                            const flags = SymbolFlags.Property | SymbolFlags.Transient | (member.questionToken ? SymbolFlags.Optional : 0);
+                            const text = getTextOfPropertyName(member.name);
+                            const symbol = <TransientSymbol>createSymbol(flags, text);
+                            symbol.type = getTypeFromTypeNodeNoAlias((member as IndexSignatureDeclaration | PropertySignature | MethodSignature).type);
+                            if (!members) {
+                                members = createMap<Symbol>();
+                            }
+                            members[symbol.name] = symbol;
+                        }
+                    }
+                    if (members) {
+                        const t = createAnonymousType(undefined, members, emptyArray, emptyArray, undefined, undefined) as SpreadElementType;
+                        t.isDeclaredProperty = true;
+                        spreads.push(t);
+                    }
+                    return getSpreadType(spreads, node.symbol);
+                }
+                else {
+                    type = createObjectType(TypeFlags.Anonymous, node.symbol);
+                }
                 type.aliasSymbol = aliasSymbol;
                 type.aliasTypeArguments = aliasTypeArguments;
                 links.resolvedType = type;
@@ -5547,6 +5712,18 @@ namespace ts {
             return links.resolvedType;
         }
 
+        function getSpreadType(types: SpreadElementType[], symbol: Symbol, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
+            const id = getTypeListId(types);
+            if (id in spreadTypes) {
+                return spreadTypes[id];
+            }
+            const spread = spreadTypes[id] = createObjectType(TypeFlags.Spread, symbol) as SpreadType;
+            spread.types = filter(types, t => !(t.flags & (TypeFlags.Null | TypeFlags.Undefined)));
+            spread.aliasSymbol = aliasSymbol;
+            spread.aliasTypeArguments = aliasTypeArguments;
+            return spread;
+        }
+
         function createLiteralType(flags: TypeFlags, text: string) {
             const type = <LiteralType>createType(flags);
             type.text = text;
@@ -5937,6 +6114,9 @@ namespace ts {
                 if (type.flags & TypeFlags.Intersection) {
                     return getIntersectionType(instantiateList((<IntersectionType>type).types, mapper, instantiateType), type.aliasSymbol, mapper.targetTypes);
                 }
+                if (type.flags & TypeFlags.Spread) {
+                    return getSpreadType(instantiateList((type as SpreadType).types, mapper, instantiateType) as SpreadElementType[], type.symbol, type.aliasSymbol, mapper.targetTypes);
+                }
             }
             return type;
         }
@@ -6460,6 +6640,26 @@ namespace ts {
                     }
                 }
 
+                if (source.flags & TypeFlags.Spread && target.flags & TypeFlags.Spread) {
+                    const sourceParameters = filter((source as SpreadType).types, t => !!(t.flags & TypeFlags.TypeParameter));
+                    const targetParameters = filter((target as SpreadType).types, t => !!(t.flags & TypeFlags.TypeParameter));
+                    if (sourceParameters.length !== targetParameters.length) {
+                        reportRelationError(headMessage, source, target);
+                        return Ternary.False;
+                    }
+                    for (let i = 0; i < sourceParameters.length; i++) {
+                        if (sourceParameters[i].symbol !== targetParameters[i].symbol) {
+                            reportRelationError(headMessage, source, target);
+                            return Ternary.False;
+                        }
+                    }
+                    const reportStructuralErrors = reportErrors && errorInfo === saveErrorInfo;
+                    if (result = objectTypeRelatedTo(source, source, target, reportStructuralErrors)) {
+                        errorInfo = saveErrorInfo;
+                        return result;
+                    }
+                }
+
                 if (source.flags & TypeFlags.TypeParameter) {
                     let constraint = getConstraintOfTypeParameter(<TypeParameter>source);
 
@@ -6490,7 +6690,7 @@ namespace ts {
                     // In a check of the form X = A & B, we will have previously checked if A relates to X or B relates
                     // to X. Failing both of those we want to check if the aggregation of A and B's members structurally
                     // relates to X. Thus, we include intersection types on the source side here.
-                    if (apparentSource.flags & (TypeFlags.ObjectType | TypeFlags.Intersection) && target.flags & TypeFlags.ObjectType) {
+                    if (apparentSource.flags & (TypeFlags.ObjectType | TypeFlags.Intersection | TypeFlags.Spread) && target.flags & TypeFlags.ObjectType) {
                         // Report structural errors only if we haven't reported any errors yet
                         const reportStructuralErrors = reportErrors && errorInfo === saveErrorInfo && !(source.flags & TypeFlags.Primitive);
                         if (result = objectTypeRelatedTo(apparentSource, source, target, reportStructuralErrors)) {
@@ -6525,8 +6725,8 @@ namespace ts {
                 }
                 if (source.flags & TypeFlags.Union && target.flags & TypeFlags.Union ||
                     source.flags & TypeFlags.Intersection && target.flags & TypeFlags.Intersection) {
-                    if (result = eachTypeRelatedToSomeType(<UnionOrIntersectionType>source, <UnionOrIntersectionType>target, /*reportErrors*/ false)) {
-                        if (result &= eachTypeRelatedToSomeType(<UnionOrIntersectionType>target, <UnionOrIntersectionType>source, /*reportErrors*/ false)) {
+                    if (result = eachTypeRelatedToSomeType(<TypeOperatorType>source, <TypeOperatorType>target, /*reportErrors*/ false)) {
+                        if (result &= eachTypeRelatedToSomeType(<TypeOperatorType>target, <TypeOperatorType>source, /*reportErrors*/ false)) {
                             return result;
                         }
                     }
@@ -6549,7 +6749,7 @@ namespace ts {
                     }
                 }
                 else if (type.flags & TypeFlags.UnionOrIntersection) {
-                    for (const t of (<UnionOrIntersectionType>type).types) {
+                    for (const t of (<TypeOperatorType>type).types) {
                         if (isKnownProperty(t, name)) {
                             return true;
                         }
@@ -6586,7 +6786,7 @@ namespace ts {
                 return false;
             }
 
-            function eachTypeRelatedToSomeType(source: UnionOrIntersectionType, target: UnionOrIntersectionType, reportErrors: boolean): Ternary {
+            function eachTypeRelatedToSomeType(source: TypeOperatorType, target: TypeOperatorType, reportErrors: boolean): Ternary {
                 let result = Ternary.True;
                 const sourceTypes = source.types;
                 for (const sourceType of sourceTypes) {
@@ -6599,7 +6799,7 @@ namespace ts {
                 return result;
             }
 
-            function typeRelatedToSomeType(source: Type, target: UnionOrIntersectionType, reportErrors: boolean): Ternary {
+            function typeRelatedToSomeType(source: Type, target: TypeOperatorType, reportErrors: boolean): Ternary {
                 const targetTypes = target.types;
                 if (target.flags & TypeFlags.Union && containsType(targetTypes, source)) {
                     return Ternary.True;
@@ -6614,7 +6814,7 @@ namespace ts {
                 return Ternary.False;
             }
 
-            function typeRelatedToEachType(source: Type, target: UnionOrIntersectionType, reportErrors: boolean): Ternary {
+            function typeRelatedToEachType(source: Type, target: TypeOperatorType, reportErrors: boolean): Ternary {
                 let result = Ternary.True;
                 const targetTypes = target.types;
                 for (const targetType of targetTypes) {
@@ -6627,7 +6827,7 @@ namespace ts {
                 return result;
             }
 
-            function someTypeRelatedToType(source: UnionOrIntersectionType, target: Type, reportErrors: boolean): Ternary {
+            function someTypeRelatedToType(source: TypeOperatorType, target: Type, reportErrors: boolean): Ternary {
                 const sourceTypes = source.types;
                 if (source.flags & TypeFlags.Union && containsType(sourceTypes, target)) {
                     return Ternary.True;
@@ -6642,7 +6842,7 @@ namespace ts {
                 return Ternary.False;
             }
 
-            function eachTypeRelatedToType(source: UnionOrIntersectionType, target: Type, reportErrors: boolean): Ternary {
+            function eachTypeRelatedToType(source: TypeOperatorType, target: Type, reportErrors: boolean): Ternary {
                 let result = Ternary.True;
                 const sourceTypes = source.types;
                 for (const sourceType of sourceTypes) {
@@ -7578,10 +7778,10 @@ namespace ts {
             return !!(type.flags & TypeFlags.TypeParameter ||
                 type.flags & TypeFlags.Reference && forEach((<TypeReference>type).typeArguments, couldContainTypeParameters) ||
                 type.flags & TypeFlags.Anonymous && type.symbol && type.symbol.flags & (SymbolFlags.Method | SymbolFlags.TypeLiteral | SymbolFlags.Class) ||
-                type.flags & TypeFlags.UnionOrIntersection && couldUnionOrIntersectionContainTypeParameters(<UnionOrIntersectionType>type));
+                type.flags & TypeFlags.UnionOrIntersection && couldUnionOrIntersectionContainTypeParameters(<TypeOperatorType>type));
         }
 
-        function couldUnionOrIntersectionContainTypeParameters(type: UnionOrIntersectionType): boolean {
+        function couldUnionOrIntersectionContainTypeParameters(type: TypeOperatorType): boolean {
             if (type.couldContainTypeParameters === undefined) {
                 type.couldContainTypeParameters = forEach(type.types, couldContainTypeParameters);
             }
@@ -7589,7 +7789,7 @@ namespace ts {
         }
 
         function isTypeParameterAtTopLevel(type: Type, typeParameter: TypeParameter): boolean {
-            return type === typeParameter || type.flags & TypeFlags.UnionOrIntersection && forEach((<UnionOrIntersectionType>type).types, t => isTypeParameterAtTopLevel(t, typeParameter));
+            return type === typeParameter || type.flags & TypeFlags.UnionOrIntersection && forEach((<TypeOperatorType>type).types, t => isTypeParameterAtTopLevel(t, typeParameter));
         }
 
         function inferTypes(context: InferenceContext, originalSource: Type, originalTarget: Type) {
@@ -7619,7 +7819,7 @@ namespace ts {
                     // Source and target are both unions or both intersections. If source and target
                     // are the same type, just relate each constituent type to itself.
                     if (source === target) {
-                        for (const t of (<UnionOrIntersectionType>source).types) {
+                        for (const t of (<TypeOperatorType>source).types) {
                             inferFromTypes(t, t);
                         }
                         return;
@@ -7631,14 +7831,14 @@ namespace ts {
                     // and string literals because the number and string types are not represented as unions
                     // of all their possible values.
                     let matchingTypes: Type[];
-                    for (const t of (<UnionOrIntersectionType>source).types) {
-                        if (typeIdenticalToSomeType(t, (<UnionOrIntersectionType>target).types)) {
+                    for (const t of (<TypeOperatorType>source).types) {
+                        if (typeIdenticalToSomeType(t, (<TypeOperatorType>target).types)) {
                             (matchingTypes || (matchingTypes = [])).push(t);
                             inferFromTypes(t, t);
                         }
                         else if (t.flags & (TypeFlags.NumberLiteral | TypeFlags.StringLiteral)) {
                             const b = getBaseTypeOfLiteralType(t);
-                            if (typeIdenticalToSomeType(b, (<UnionOrIntersectionType>target).types)) {
+                            if (typeIdenticalToSomeType(b, (<TypeOperatorType>target).types)) {
                                 (matchingTypes || (matchingTypes = [])).push(t, b);
                             }
                         }
@@ -7647,8 +7847,8 @@ namespace ts {
                     // removing the identically matched constituents. For example, when inferring from
                     // 'string | string[]' to 'string | T' we reduce the types to 'string[]' and 'T'.
                     if (matchingTypes) {
-                        source = removeTypesFromUnionOrIntersection(<UnionOrIntersectionType>source, matchingTypes);
-                        target = removeTypesFromUnionOrIntersection(<UnionOrIntersectionType>target, matchingTypes);
+                        source = removeTypesFromUnionOrIntersection(<TypeOperatorType>source, matchingTypes);
+                        target = removeTypesFromUnionOrIntersection(<TypeOperatorType>target, matchingTypes);
                     }
                 }
                 if (target.flags & TypeFlags.TypeParameter) {
@@ -7695,7 +7895,7 @@ namespace ts {
                     }
                 }
                 else if (target.flags & TypeFlags.UnionOrIntersection) {
-                    const targetTypes = (<UnionOrIntersectionType>target).types;
+                    const targetTypes = (<TypeOperatorType>target).types;
                     let typeParameterCount = 0;
                     let typeParameter: TypeParameter;
                     // First infer to each type in union or intersection that isn't a type parameter
@@ -7719,7 +7919,7 @@ namespace ts {
                 }
                 else if (source.flags & TypeFlags.UnionOrIntersection) {
                     // Source is a union or intersection type, infer from each constituent type
-                    const sourceTypes = (<UnionOrIntersectionType>source).types;
+                    const sourceTypes = (<TypeOperatorType>source).types;
                     for (const sourceType of sourceTypes) {
                         inferFromTypes(sourceType, target);
                     }
@@ -7824,7 +8024,7 @@ namespace ts {
          * Return a new union or intersection type computed by removing a given set of types
          * from a given union or intersection type.
          */
-        function removeTypesFromUnionOrIntersection(type: UnionOrIntersectionType, typesToRemove: Type[]) {
+        function removeTypesFromUnionOrIntersection(type: TypeOperatorType, typesToRemove: Type[]) {
             const reducedTypes: Type[] = [];
             for (const t of type.types) {
                 if (!typeIdenticalToSomeType(t, typesToRemove)) {
@@ -8148,7 +8348,7 @@ namespace ts {
                 return getTypeFacts(constraint || emptyObjectType);
             }
             if (flags & TypeFlags.UnionOrIntersection) {
-                return getTypeFactsOfTypes((<UnionOrIntersectionType>type).types);
+                return getTypeFactsOfTypes((<TypeOperatorType>type).types);
             }
             return TypeFacts.All;
         }
@@ -10184,8 +10384,9 @@ namespace ts {
             // Grammar checking
             checkGrammarObjectLiteralExpression(node, inDestructuringPattern);
 
-            const propertiesTable = createMap<Symbol>();
-            const propertiesArray: Symbol[] = [];
+            let propertiesTable = createMap<Symbol>();
+            let propertiesArray: Symbol[] = [];
+            const spreads: SpreadElementType[] = [];
             const contextualType = getApparentTypeOfContextualType(node);
             const contextualTypeHasPattern = contextualType && contextualType.pattern &&
                 (contextualType.pattern.kind === SyntaxKind.ObjectBindingPattern || contextualType.pattern.kind === SyntaxKind.ObjectLiteralExpression);
@@ -10210,6 +10411,14 @@ namespace ts {
                         Debug.assert(memberDecl.kind === SyntaxKind.ShorthandPropertyAssignment);
                         type = checkExpressionForMutableLocation((<ShorthandPropertyAssignment>memberDecl).name, contextualMapper);
                     }
+
+                    if (hasProperty(propertiesTable, member.name)) {
+                        const existingPropType = getTypeOfSymbol(propertiesTable[member.name]);
+                        if (!isTypeIdenticalTo(existingPropType, type)) {
+                            error(memberDecl.name, Diagnostics.Cannot_change_type_of_property_0_from_1_to_2, member.name, typeToString(existingPropType), typeToString(type));
+                        }
+                    }
+
                     typeFlags |= type.flags;
                     const prop = <TransientSymbol>createSymbol(SymbolFlags.Property | SymbolFlags.Transient | member.flags, member.name);
                     if (inDestructuringPattern) {
@@ -10247,6 +10456,19 @@ namespace ts {
                     prop.target = member;
                     member = prop;
                 }
+                else if (memberDecl.kind === SyntaxKind.SpreadElement) {
+                    if (propertiesArray.length > 0) {
+                        const t = createObjectLiteralType(node, hasComputedStringProperty, hasComputedNumberProperty, propertiesArray, propertiesTable, typeFlags, patternWithComputedProperties, inDestructuringPattern) as SpreadElementType;
+                        t.isDeclaredProperty = true;
+                        spreads.push(t);
+                        propertiesArray = [];
+                        propertiesTable = createMap<Symbol>();
+                        hasComputedStringProperty = false;
+                        hasComputedNumberProperty = false;
+                    }
+                    spreads.push(checkExpression((memberDecl as SpreadElement).target) as SpreadElementType);
+                    continue;
+                }
                 else {
                     // TypeScript 1.0 spec (April 2014)
                     // A get accessor declaration is processed in the same manner as
@@ -10286,6 +10508,22 @@ namespace ts {
                 }
             }
 
+            if (spreads.length > 0) {
+                if (propertiesArray.length > 0) {
+                    const t = createObjectLiteralType(node, hasComputedStringProperty, hasComputedNumberProperty, propertiesArray, propertiesTable, typeFlags, patternWithComputedProperties, inDestructuringPattern) as SpreadElementType;
+                    t.isDeclaredProperty = true;
+                    spreads.push(t);
+                }
+                const propagatedFlags = getPropagatingFlagsOfTypes(spreads, /*excludeKinds*/ TypeFlags.Nullable);
+                const spread = getSpreadType(spreads, node.symbol);
+                spread.flags |= propagatedFlags;
+                return spread;
+            }
+
+            return createObjectLiteralType(node, hasComputedStringProperty, hasComputedNumberProperty, propertiesArray, propertiesTable, typeFlags, patternWithComputedProperties, inDestructuringPattern);
+        }
+
+        function createObjectLiteralType(node: ObjectLiteralExpression, hasComputedStringProperty: boolean, hasComputedNumberProperty: boolean, propertiesArray: Symbol[], propertiesTable: Map<Symbol>, typeFlags: TypeFlags, patternWithComputedProperties: boolean, inDestructuringPattern: boolean) {
             const stringIndexInfo = hasComputedStringProperty ? getObjectLiteralIndexInfo(node, propertiesArray, IndexKind.String) : undefined;
             const numberIndexInfo = hasComputedNumberProperty ? getObjectLiteralIndexInfo(node, propertiesArray, IndexKind.Number) : undefined;
             const result = createAnonymousType(node.symbol, propertiesTable, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
@@ -10534,7 +10772,7 @@ namespace ts {
                 elemType = checkExpression(node.tagName);
             }
             if (elemType.flags & TypeFlags.Union) {
-                const types = (<UnionOrIntersectionType>elemType).types;
+                const types = (<TypeOperatorType>elemType).types;
                 return getUnionType(types.map(type => {
                     return getResolvedJsxType(node, type, elemClassType);
                 }), /*subtypeReduction*/ true);
@@ -13096,7 +13334,7 @@ namespace ts {
                 return true;
             }
             if (type.flags & TypeFlags.UnionOrIntersection) {
-                const types = (<UnionOrIntersectionType>type).types;
+                const types = (<TypeOperatorType>type).types;
                 for (const t of types) {
                     if (maybeTypeOfKind(t, kind)) {
                         return true;
@@ -13114,7 +13352,7 @@ namespace ts {
                 return true;
             }
             if (type.flags & TypeFlags.Union) {
-                const types = (<UnionOrIntersectionType>type).types;
+                const types = (<TypeOperatorType>type).types;
                 for (const t of types) {
                     if (!isTypeOfKind(t, kind)) {
                         return false;
@@ -13123,7 +13361,7 @@ namespace ts {
                 return true;
             }
             if (type.flags & TypeFlags.Intersection) {
-                const types = (<UnionOrIntersectionType>type).types;
+                const types = (<TypeOperatorType>type).types;
                 for (const t of types) {
                     if (isTypeOfKind(t, kind)) {
                         return true;
@@ -19194,7 +19432,7 @@ namespace ts {
                     if (requestedExternalEmitHelpers & NodeFlags.HasClassExtends && languageVersion < ScriptTarget.ES6) {
                         verifyHelperSymbol(exports, "__extends", SymbolFlags.Value);
                     }
-                    if (requestedExternalEmitHelpers & NodeFlags.HasJsxSpreadAttributes && compilerOptions.jsx !== JsxEmit.Preserve) {
+                    if (requestedExternalEmitHelpers & NodeFlags.HasSpreadAttribute && compilerOptions.jsx !== JsxEmit.Preserve) {
                         verifyHelperSymbol(exports, "__assign", SymbolFlags.Value);
                     }
                     if (requestedExternalEmitHelpers & NodeFlags.HasDecorators) {
@@ -19758,6 +19996,11 @@ namespace ts {
                 }
             }
 
+            let result: TypeElement;
+            if (result = find(node.members, e => e.kind === SyntaxKind.SpreadTypeElement)) {
+                return grammarErrorOnNode(result, Diagnostics.Interface_declaration_cannot_contain_a_spread_property);
+            }
+
             return false;
         }
 
@@ -19805,9 +20048,23 @@ namespace ts {
             const GetOrSetAccessor = GetAccessor | SetAccessor;
 
             for (const prop of node.properties) {
+                if (prop.kind === SyntaxKind.SpreadElement) {
+                    const target = (prop as SpreadElement).target;
+                    switch (target.kind) {
+                        case SyntaxKind.Identifier:
+                        case SyntaxKind.PropertyAccessExpression:
+                        case SyntaxKind.ObjectLiteralExpression:
+                        case SyntaxKind.NullKeyword:
+                            break;
+                        default:
+                            grammarErrorOnNode(target, Diagnostics.Spread_properties_must_be_identifiers_property_accesses_or_object_literals);
+                    }
+
+                    continue;
+                }
                 const name = prop.name;
                 if (prop.kind === SyntaxKind.OmittedExpression ||
-                    name.kind === SyntaxKind.ComputedPropertyName) {
+                    name && name.kind === SyntaxKind.ComputedPropertyName) {
                     // If the name is not a ComputedPropertyName, the grammar checking will skip it
                     checkGrammarComputedPropertyName(<ComputedPropertyName>name);
                 }
@@ -20127,7 +20384,7 @@ namespace ts {
                 }
 
                 if (node.initializer) {
-                    // Error on equals token which immediate precedes the initializer
+                    // Error on equals token which immediately precedes the initializer
                     return grammarErrorAtPos(getSourceFileOfNode(node), node.initializer.pos - 1, 1, Diagnostics.A_rest_element_cannot_have_an_initializer);
                 }
             }
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index be4ee2fa07d98..69c2a431fc845 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1963,6 +1963,18 @@
         "category": "Error",
         "code": 2696
     },
+    "Spread properties must be identifiers, property accesses, or object literals.": {
+        "category": "Error",
+        "code": 2697
+    },
+    "Cannot change type of property '{0}' from '{1}' to '{2}'.": {
+        "category": "Error",
+        "code": 2698
+    },
+    "Interface declaration cannot contain a spread property.": {
+        "category": "Error",
+        "code": 2699
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 1aec63bc588ca..ae88b6d948b5b 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -74,6 +74,11 @@ namespace ts {
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).questionToken) ||
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).equalsToken) ||
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).objectAssignmentInitializer);
+            case SyntaxKind.SpreadElement:
+                return visitNode(cbNode, (<SpreadElement>node).dotDotDotToken) ||
+                    visitNode(cbNode, (<SpreadElement>node).target);
+            case SyntaxKind.SpreadTypeElement:
+                return visitNode(cbNode, (node as SpreadTypeElement).type);
             case SyntaxKind.Parameter:
             case SyntaxKind.PropertyDeclaration:
             case SyntaxKind.PropertySignature:
@@ -1262,7 +1267,7 @@ namespace ts {
                     // which would be a candidate for improved error reporting.
                     return token() === SyntaxKind.OpenBracketToken || isLiteralPropertyName();
                 case ParsingContext.ObjectLiteralMembers:
-                    return token() === SyntaxKind.OpenBracketToken || token() === SyntaxKind.AsteriskToken || isLiteralPropertyName();
+                    return token() === SyntaxKind.OpenBracketToken || token() === SyntaxKind.AsteriskToken || token() === SyntaxKind.DotDotDotToken || isLiteralPropertyName();
                 case ParsingContext.ObjectBindingElements:
                     return token() === SyntaxKind.OpenBracketToken || isLiteralPropertyName();
                 case ParsingContext.HeritageClauseElement:
@@ -2328,6 +2333,10 @@ namespace ts {
             if (token() === SyntaxKind.OpenBracketToken) {
                 return true;
             }
+            // spread elements are type members
+            if (token() === SyntaxKind.DotDotDotToken) {
+                return true;
+            }
             // Try to get the first property-like token following all modifiers
             if (isLiteralPropertyName()) {
                 idToken = token();
@@ -2353,6 +2362,9 @@ namespace ts {
             if (token() === SyntaxKind.NewKeyword && lookAhead(isStartOfConstructSignature)) {
                 return parseSignatureMember(SyntaxKind.ConstructSignature);
             }
+            if (token() === SyntaxKind.DotDotDotToken) {
+                return parseSpreadTypeElement();
+            }
             const fullStart = getNodePos();
             const modifiers = parseModifiers();
             if (isIndexSignature()) {
@@ -2361,6 +2373,14 @@ namespace ts {
             return parsePropertyOrMethodSignature(fullStart, modifiers);
         }
 
+        function parseSpreadTypeElement() {
+            const element = createNode(SyntaxKind.SpreadTypeElement, scanner.getStartPos()) as SpreadTypeElement;
+            parseTokenNode<Node>(); // parse `...`
+            element.type = parseType();
+            parseTypeMemberSemicolon();
+            return finishNode(element);
+        }
+
         function isStartOfConstructSignature() {
             nextToken();
             return token() === SyntaxKind.OpenParenToken || token() === SyntaxKind.LessThanToken;
@@ -4123,6 +4143,13 @@ namespace ts {
 
         function parseObjectLiteralElement(): ObjectLiteralElement {
             const fullStart = scanner.getStartPos();
+            const dotDotDotToken = parseOptionalToken(SyntaxKind.DotDotDotToken);
+            if (dotDotDotToken) {
+                const spreadElement = <SpreadElement>createNode(SyntaxKind.SpreadElement, fullStart);
+                spreadElement.dotDotDotToken = dotDotDotToken;
+                spreadElement.target = parseAssignmentExpressionOrHigher();
+                return addJSDocComment(finishNode(spreadElement));
+            }
             const decorators = parseDecorators();
             const modifiers = parseModifiers();
 
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index e4bc9a29d5b03..cdf42ebea4ffc 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -316,6 +316,9 @@ namespace ts {
         // Property assignments
         PropertyAssignment,
         ShorthandPropertyAssignment,
+        SpreadElement, // maybe name it SpreadProperty?
+        SpreadTypeElement, // maybe name it SpreadTypeNode?
+
 
         // Enum
         EnumMember,
@@ -412,7 +415,7 @@ namespace ts {
         HasDecorators =      1 << 11, // If the file has decorators (initialized by binding)
         HasParamDecorators = 1 << 12, // If the file has parameter decorators (initialized by binding)
         HasAsyncFunctions =  1 << 13, // If the file has async functions (initialized by binding)
-        HasJsxSpreadAttributes = 1 << 14, // If the file as JSX spread attributes (initialized by binding)
+        HasSpreadAttribute = 1 << 14, // If the file as JSX spread attributes (initialized by binding)
         DisallowInContext =  1 << 15, // If node was parsed in a context where 'in-expressions' are not allowed
         YieldContext =       1 << 16, // If node was parsed in the 'yield' context created when parsing a generator
         DecoratorContext =   1 << 17, // If node was parsed as part of a decorator
@@ -425,7 +428,7 @@ namespace ts {
         BlockScoped = Let | Const,
 
         ReachabilityCheckFlags = HasImplicitReturn | HasExplicitReturn,
-        EmitHelperFlags = HasClassExtends | HasDecorators | HasParamDecorators | HasAsyncFunctions | HasJsxSpreadAttributes,
+        EmitHelperFlags = HasClassExtends | HasDecorators | HasParamDecorators | HasAsyncFunctions | HasSpreadAttribute,
         ReachabilityAndEmitFlags = ReachabilityCheckFlags | EmitHelperFlags,
 
         // Parsing context flags
@@ -450,7 +453,6 @@ namespace ts {
         Async =              1 << 8,  // Property/Method/Function
         Default =            1 << 9,  // Function/Class (export default declaration)
         Const =              1 << 11, // Variable declaration
-
         HasComputedFlags =   1 << 29, // Modifier flags have been computed
 
         AccessibilityModifier = Public | Private | Protected,
@@ -635,6 +637,11 @@ namespace ts {
         initializer?: Expression;           // Optional initializer
     }
 
+    // @kind(SyntaxKind.SpreadTypeElement)
+    export interface SpreadTypeElement extends TypeElement {
+        type: TypeNode;
+    }
+
     // @kind(SyntaxKind.PropertyDeclaration)
     export interface PropertyDeclaration extends ClassElement {
         questionToken?: Node;               // Present for use with reporting a grammar error
@@ -666,6 +673,12 @@ namespace ts {
         objectAssignmentInitializer?: Expression;
     }
 
+    // @kind(SyntaxKind.SpreadElementExpression)
+    export interface SpreadElement extends ObjectLiteralElement {
+        dotDotDotToken: Node;
+        target: Expression;
+    }
+
     // SyntaxKind.VariableDeclaration
     // SyntaxKind.Parameter
     // SyntaxKind.BindingElement
@@ -2275,7 +2288,7 @@ namespace ts {
         instantiations?: Map<Type>;         // Instantiations of generic type alias (undefined if non-generic)
         mapper?: TypeMapper;                // Type mapper for instantiation alias
         referenced?: boolean;               // True if alias symbol has been referenced as a value
-        containingType?: UnionOrIntersectionType; // Containing union or intersection type for synthetic property
+        containingType?: TypeOperatorType; // Containing union or intersection type for synthetic property
         hasCommonType?: boolean;            // True if constituents of synthetic property all have same type
         isDiscriminantProperty?: boolean;   // True if discriminant synthetic property
         resolvedExports?: SymbolTable;      // Resolved exports of module
@@ -2381,6 +2394,8 @@ namespace ts {
         ContainsAnyFunctionType = 1 << 27,  // Type is or contains object literal type
         ThisType                = 1 << 28,  // This type
         ObjectLiteralPatternWithComputedProperties = 1 << 29,  // Object literal type implied by binding pattern has computed properties
+        Spread                  = 1 << 30,  // Spread types
+        // TODO: Move some types out to make room for Spread.
 
         /* @internal */
         Nullable = Undefined | Null,
@@ -2398,12 +2413,12 @@ namespace ts {
         EnumLike = Enum | EnumLiteral,
         ObjectType = Class | Interface | Reference | Tuple | Anonymous,
         UnionOrIntersection = Union | Intersection,
-        StructuredType = ObjectType | Union | Intersection,
+        StructuredType = ObjectType | Union | Intersection | Spread,
         StructuredOrTypeParameter = StructuredType | TypeParameter,
 
         // 'Narrowable' types are types where narrowing actually narrows.
         // This *should* be every type other than null, undefined, void, and never
-        Narrowable = Any | StructuredType | TypeParameter | StringLike | NumberLike | BooleanLike | ESSymbol,
+        Narrowable = Any | StructuredType | TypeParameter | StringLike | NumberLike | BooleanLike | ESSymbol | Spread,
         NotUnionOrUnit = Any | String | Number | ESSymbol | ObjectType,
         /* @internal */
         RequiresWidening = ContainsWideningType | ContainsObjectLiteral,
@@ -2486,7 +2501,7 @@ namespace ts {
         instantiations: Map<TypeReference>;   // Generic instantiation cache
     }
 
-    export interface UnionOrIntersectionType extends Type {
+    export interface TypeOperatorType extends Type {
         types: Type[];                    // Constituent types
         /* @internal */
         resolvedProperties: SymbolTable;  // Cache of resolved properties
@@ -2494,9 +2509,19 @@ namespace ts {
         couldContainTypeParameters: boolean;
     }
 
-    export interface UnionType extends UnionOrIntersectionType { }
+    export interface UnionType extends TypeOperatorType { }
+
+    export interface IntersectionType extends TypeOperatorType { }
 
-    export interface IntersectionType extends UnionOrIntersectionType { }
+    /* @internal */
+    export interface SpreadType extends TypeOperatorType {
+        types: SpreadElementType[];       // Constituent types
+    }
+
+    /* @internal */
+    export interface SpreadElementType extends ResolvedType {
+        isDeclaredProperty: boolean | undefined;
+    }
 
     /* @internal */
     // An instantiated anonymous type has a target and a mapper
@@ -2506,8 +2531,8 @@ namespace ts {
     }
 
     /* @internal */
-    // Resolved object, union, or intersection type
-    export interface ResolvedType extends ObjectType, UnionOrIntersectionType {
+    // Resolved object, spread, union, or intersection type
+    export interface ResolvedType extends ObjectType, TypeOperatorType {
         members: SymbolTable;              // Properties by name
         properties: Symbol[];              // Properties
         callSignatures: Signature[];       // Call signatures of type
@@ -3096,29 +3121,31 @@ namespace ts {
         ContainsTypeScript = 1 << 1,
         Jsx = 1 << 2,
         ContainsJsx = 1 << 3,
-        ES7 = 1 << 4,
-        ContainsES7 = 1 << 5,
-        ES6 = 1 << 6,
-        ContainsES6 = 1 << 7,
-        DestructuringAssignment = 1 << 8,
-        Generator = 1 << 9,
-        ContainsGenerator = 1 << 10,
+        Experimental = 1 << 4,
+        ContainsExperimental = 1 << 5,
+        ES7 = 1 << 6,
+        ContainsES7 = 1 << 7,
+        ES6 = 1 << 8,
+        ContainsES6 = 1 << 9,
+        DestructuringAssignment = 1 << 10,
+        Generator = 1 << 11,
+        ContainsGenerator = 1 << 12,
 
         // Markers
         // - Flags used to indicate that a subtree contains a specific transformation.
-        ContainsDecorators = 1 << 11,
-        ContainsPropertyInitializer = 1 << 12,
-        ContainsLexicalThis = 1 << 13,
-        ContainsCapturedLexicalThis = 1 << 14,
-        ContainsLexicalThisInComputedPropertyName = 1 << 15,
-        ContainsDefaultValueAssignments = 1 << 16,
-        ContainsParameterPropertyAssignments = 1 << 17,
-        ContainsSpreadElementExpression = 1 << 18,
-        ContainsComputedPropertyName = 1 << 19,
-        ContainsBlockScopedBinding = 1 << 20,
-        ContainsBindingPattern = 1 << 21,
-        ContainsYield = 1 << 22,
-        ContainsHoistedDeclarationOrCompletion = 1 << 23,
+        ContainsDecorators = 1 << 13,
+        ContainsPropertyInitializer = 1 << 14,
+        ContainsLexicalThis = 1 << 15,
+        ContainsCapturedLexicalThis = 1 << 16,
+        ContainsLexicalThisInComputedPropertyName = 1 << 17,
+        ContainsDefaultValueAssignments = 1 << 18,
+        ContainsParameterPropertyAssignments = 1 << 19,
+        ContainsSpreadElementExpression = 1 << 20,
+        ContainsComputedPropertyName = 1 << 21,
+        ContainsBlockScopedBinding = 1 << 22,
+        ContainsBindingPattern = 1 << 23,
+        ContainsYield = 1 << 24,
+        ContainsHoistedDeclarationOrCompletion = 1 << 25,
 
         HasComputedFlags = 1 << 29, // Transform flags have been computed.
 
@@ -3126,6 +3153,7 @@ namespace ts {
         // - Bitmasks that are used to assert facts about the syntax of a node and its subtree.
         AssertTypeScript = TypeScript | ContainsTypeScript,
         AssertJsx = Jsx | ContainsJsx,
+        AssertExperimental = Experimental | ContainsExperimental,
         AssertES7 = ES7 | ContainsES7,
         AssertES6 = ES6 | ContainsES6,
         AssertGenerator = Generator | ContainsGenerator,
@@ -3133,7 +3161,7 @@ namespace ts {
         // Scope Exclusions
         // - Bitmasks that exclude flags from propagating out of a specific context
         //   into the subtree flags of their container.
-        NodeExcludes = TypeScript | Jsx | ES7 | ES6 | DestructuringAssignment | Generator | HasComputedFlags,
+        NodeExcludes = TypeScript | Jsx | Experimental | ES7 | ES6 | DestructuringAssignment | Generator | HasComputedFlags,
         ArrowFunctionExcludes = NodeExcludes | ContainsDecorators | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsParameterPropertyAssignments | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,
         FunctionExcludes = NodeExcludes | ContainsDecorators | ContainsDefaultValueAssignments | ContainsCapturedLexicalThis | ContainsLexicalThis | ContainsParameterPropertyAssignments | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,
         ConstructorExcludes = NodeExcludes | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 7a22c5634d84f..67ea182bf9868 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -3740,6 +3740,7 @@ namespace ts {
         const kind = node.kind;
         return kind === SyntaxKind.PropertyAssignment
             || kind === SyntaxKind.ShorthandPropertyAssignment
+            || kind === SyntaxKind.SpreadElement
             || kind === SyntaxKind.MethodDeclaration
             || kind === SyntaxKind.GetAccessor
             || kind === SyntaxKind.SetAccessor
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index b4fd8736b2f7d..3d050b2cf2c6c 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -1463,7 +1463,7 @@ namespace Harness {
             }
 
             if (typesError && symbolsError) {
-                throw new Error(typesError.message + ts.sys.newLine + symbolsError.message);
+                throw new Error(typesError.message + Harness.IO.newLine() + symbolsError.message);
             }
 
             if (typesError) {
diff --git a/src/services/findAllReferences.ts b/src/services/findAllReferences.ts
index dcda3e40b1a67..8766937c00851 100644
--- a/src/services/findAllReferences.ts
+++ b/src/services/findAllReferences.ts
@@ -458,7 +458,7 @@ namespace ts.FindAllReferences {
                                 return [localParentType.symbol];
                             }
                             else if (localParentType.flags & TypeFlags.UnionOrIntersection) {
-                                return getSymbolsForClassAndInterfaceComponents(<UnionOrIntersectionType>localParentType);
+                                return getSymbolsForClassAndInterfaceComponents(<TypeOperatorType>localParentType);
                             }
                         }
                     }
@@ -630,13 +630,13 @@ namespace ts.FindAllReferences {
             }
         }
 
-        function getSymbolsForClassAndInterfaceComponents(type: UnionOrIntersectionType, result: Symbol[] = []): Symbol[] {
+        function getSymbolsForClassAndInterfaceComponents(type: TypeOperatorType, result: Symbol[] = []): Symbol[] {
             for (const componentType of type.types) {
                 if (componentType.symbol && componentType.symbol.getFlags() & (SymbolFlags.Class | SymbolFlags.Interface)) {
                     result.push(componentType.symbol);
                 }
                 if (componentType.getFlags() & TypeFlags.UnionOrIntersection) {
-                    getSymbolsForClassAndInterfaceComponents(<UnionOrIntersectionType>componentType, result);
+                    getSymbolsForClassAndInterfaceComponents(<TypeOperatorType>componentType, result);
                 }
             }
             return result;

From 7004652a0a714364eb627591df5e288220c58226 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 26 Sep 2016 09:31:34 -0700
Subject: [PATCH 002/224] Declaration emit spread types and downlevel spread

---
 src/compiler/declarationEmitter.ts        | 10 +++
 src/compiler/emitter.ts                   |  2 +-
 src/compiler/transformer.ts               |  4 +-
 src/compiler/transformers/es7.ts          |  3 +-
 src/compiler/transformers/experimental.ts | 80 +++++++++++++++++++++++
 5 files changed, 95 insertions(+), 4 deletions(-)
 create mode 100644 src/compiler/transformers/experimental.ts

diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index a015ad79b9791..58ed2211160bd 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -1121,6 +1121,14 @@ namespace ts {
             writeLine();
         }
 
+
+        function emitSpreadTypeElement(type: SpreadTypeElement) {
+            write("...");
+            emitType(type.type);
+            write(";");
+            writeLine();
+        }
+
         function emitVariableDeclaration(node: VariableDeclaration) {
             // If we are emitting property it isn't moduleElement and hence we already know it needs to be emitted
             // so there is no check needed to see if declaration is visible
@@ -1702,6 +1710,8 @@ namespace ts {
                 case SyntaxKind.PropertyDeclaration:
                 case SyntaxKind.PropertySignature:
                     return emitPropertyDeclaration(<PropertyDeclaration>node);
+                case SyntaxKind.SpreadTypeElement:
+                    return emitSpreadTypeElement(node as SpreadTypeElement);
                 case SyntaxKind.EnumMember:
                     return emitEnumMemberDeclaration(<EnumMember>node);
                 case SyntaxKind.ExportAssignment:
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 14e743cf59f76..cd00f7ad76905 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -2195,7 +2195,7 @@ const _super = (function (geti, seti) {
                 helpersEmitted = true;
             }
 
-            if (compilerOptions.jsx !== JsxEmit.Preserve && !assignEmitted && (node.flags & NodeFlags.HasJsxSpreadAttributes)) {
+            if (compilerOptions.jsx !== JsxEmit.Preserve && !assignEmitted && (node.flags & NodeFlags.HasSpreadAttribute)) {
                 writeLines(assignHelper);
                 assignEmitted = true;
             }
diff --git a/src/compiler/transformer.ts b/src/compiler/transformer.ts
index 6242a2f23474c..2fa57730bf085 100644
--- a/src/compiler/transformer.ts
+++ b/src/compiler/transformer.ts
@@ -1,6 +1,7 @@
 /// <reference path="visitor.ts" />
 /// <reference path="transformers/ts.ts" />
 /// <reference path="transformers/jsx.ts" />
+/// <reference path="transformers/experimental.ts" />
 /// <reference path="transformers/es7.ts" />
 /// <reference path="transformers/es6.ts" />
 /// <reference path="transformers/generators.ts" />
@@ -176,6 +177,7 @@ namespace ts {
             transformers.push(transformJsx);
         }
 
+        transformers.push(transformExperimental);
         transformers.push(transformES7);
 
         if (languageVersion < ScriptTarget.ES6) {
@@ -629,4 +631,4 @@ namespace ts {
             return t => t;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/compiler/transformers/es7.ts b/src/compiler/transformers/es7.ts
index 5d848bc608bad..5aaaacb9ecd7a 100644
--- a/src/compiler/transformers/es7.ts
+++ b/src/compiler/transformers/es7.ts
@@ -28,7 +28,6 @@ namespace ts {
             switch (node.kind) {
                 case SyntaxKind.BinaryExpression:
                     return visitBinaryExpression(<BinaryExpression>node);
-
                 default:
                     Debug.failBadSyntaxKind(node);
                     return visitEachChild(node, visitor, context);
@@ -94,4 +93,4 @@ namespace ts {
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/compiler/transformers/experimental.ts b/src/compiler/transformers/experimental.ts
new file mode 100644
index 0000000000000..715cf91afd3e6
--- /dev/null
+++ b/src/compiler/transformers/experimental.ts
@@ -0,0 +1,80 @@
+/// <reference path="../factory.ts" />
+/// <reference path="../visitor.ts" />
+
+/*@internal*/
+namespace ts {
+    export function transformExperimental(context: TransformationContext) {
+        return transformSourceFile;
+
+        function transformSourceFile(node: SourceFile) {
+            return visitEachChild(node, visitor, context);
+        }
+
+        function visitor(node: Node): VisitResult<Node> {
+            if (node.transformFlags & TransformFlags.Experimental) {
+                return visitorWorker(node);
+            }
+            else if (node.transformFlags & TransformFlags.ContainsExperimental) {
+                return visitEachChild(node, visitor, context);
+            }
+            else {
+                return node;
+            }
+        }
+
+        function visitorWorker(node: Node): VisitResult<Node> {
+            switch (node.kind) {
+                case SyntaxKind.ObjectLiteralExpression:
+                    return visitObjectLiteralExpression(node as ObjectLiteralExpression);
+                default:
+                    Debug.failBadSyntaxKind(node);
+                    return visitEachChild(node, visitor, context);
+            }
+        }
+
+        function chunkObjectLiteralElements(elements: ObjectLiteralElement[]): Expression[] {
+            let chunkObject: (ShorthandPropertyAssignment | PropertyAssignment)[];
+            const objects: Expression[] = [];
+            for (const e of elements) {
+                if (e.kind === SyntaxKind.SpreadElement) {
+                    if (chunkObject) {
+                        objects.push(createObjectLiteral(chunkObject));
+                        chunkObject = undefined;
+                    }
+                    const target = (e as SpreadElement).target;
+                    objects.push(visitNode(target, visitor, isExpression));
+                }
+                else {
+                    if (!chunkObject) {
+                        chunkObject = [];
+                    }
+                    if (e.kind === SyntaxKind.PropertyAssignment) {
+                        const p = e as PropertyAssignment;
+                        chunkObject.push(createPropertyAssignment(p.name, visitNode(p.initializer, visitor, isExpression)));
+                    }
+                    else {
+                        chunkObject.push(e as ShorthandPropertyAssignment);
+                    }
+                }
+            }
+            if (chunkObject) {
+                objects.push(createObjectLiteral(chunkObject));
+            }
+
+            return objects;
+        }
+
+        function visitObjectLiteralExpression(node: ObjectLiteralExpression): Expression {
+            // spread elements emit like so:
+            // non-spread elements are chunked together into object literals, and then all are passed to __assign:
+            //     { a, ...o, b } => __assign({a}, o, {b});
+            // If the first element is a spread element, then the first argument to __assign is {}:
+            //     { ...o, a, b, ...o2 } => __assign({}, o, {a, b}, o2)
+            const objects = chunkObjectLiteralElements(node.properties);
+            if (objects.length && objects[0].kind !== SyntaxKind.ObjectLiteralExpression) {
+                objects.unshift(createObjectLiteral());
+            }
+            return createCall(createIdentifier("__assign"), undefined, objects);
+        }
+    }
+}

From bf866cea7b82f8c22d648acbe6815cfa9632d8db Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 26 Sep 2016 09:32:23 -0700
Subject: [PATCH 003/224] Update build files

---
 Jakefile.js                | 2 ++
 src/compiler/tsconfig.json | 1 +
 src/harness/tsconfig.json  | 1 +
 src/services/tsconfig.json | 1 +
 4 files changed, 5 insertions(+)

diff --git a/Jakefile.js b/Jakefile.js
index c62a4ffd6ce0e..6b749d4a4ef83 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -72,6 +72,7 @@ var compilerSources = [
     "transformers/module/system.ts",
     "transformers/module/module.ts",
     "transformers/jsx.ts",
+    "transformers/experimental.ts",
     "transformers/es7.ts",
     "transformers/generators.ts",
     "transformers/es6.ts",
@@ -106,6 +107,7 @@ var servicesSources = [
     "transformers/module/system.ts",
     "transformers/module/module.ts",
     "transformers/jsx.ts",
+    "transformers/experimental.ts",
     "transformers/es7.ts",
     "transformers/generators.ts",
     "transformers/es6.ts",
diff --git a/src/compiler/tsconfig.json b/src/compiler/tsconfig.json
index f128c994af12b..9681aba0d8f1c 100644
--- a/src/compiler/tsconfig.json
+++ b/src/compiler/tsconfig.json
@@ -24,6 +24,7 @@
         "visitor.ts",
         "transformers/ts.ts",
         "transformers/jsx.ts",
+        "transformers/experimental.ts",
         "transformers/es7.ts",
         "transformers/es6.ts",
         "transformers/generators.ts",
diff --git a/src/harness/tsconfig.json b/src/harness/tsconfig.json
index 8444d1d4a751e..fda4c68272ef1 100644
--- a/src/harness/tsconfig.json
+++ b/src/harness/tsconfig.json
@@ -26,6 +26,7 @@
         "../compiler/visitor.ts",
         "../compiler/transformers/ts.ts",
         "../compiler/transformers/jsx.ts",
+        "../compiler/transformers/experimental.ts",
         "../compiler/transformers/es7.ts",
         "../compiler/transformers/es6.ts",
         "../compiler/transformers/generators.ts",
diff --git a/src/services/tsconfig.json b/src/services/tsconfig.json
index 58312c6f38ff3..8d612fb7a7557 100644
--- a/src/services/tsconfig.json
+++ b/src/services/tsconfig.json
@@ -25,6 +25,7 @@
         "../compiler/visitor.ts",
         "../compiler/transformers/ts.ts",
         "../compiler/transformers/jsx.ts",
+        "../compiler/transformers/experimental.ts",
         "../compiler/transformers/es7.ts",
         "../compiler/transformers/es6.ts",
         "../compiler/transformers/generators.ts",

From 0fea59f642604ecd105c424deae982a73b4032c7 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 26 Sep 2016 09:33:08 -0700
Subject: [PATCH 004/224] Add spread tests

---
 ...uringObjectBindingPatternAndAssignment3.ts |  5 +-
 .../es6/destructuring/interfaceSpread.ts      |  8 ++
 .../conformance/types/spread/objectSpread.ts  | 96 +++++++++++++++++++
 .../types/spread/objectSpreadGeneric.ts       | 40 ++++++++
 .../types/spread/objectSpreadNegative.ts      | 49 ++++++++++
 .../types/spread/objectSpreadNegativeParse.ts |  4 +
 .../completionListForObjectSpread.ts          | 35 +++++++
 .../fourslash/findAllRefsForObjectSpread.ts   | 12 +++
 .../fourslash/goToDefinitionObjectSpread.ts   |  7 ++
 tests/cases/fourslash/renameObjectSpread.ts   | 18 ++++
 10 files changed, 270 insertions(+), 4 deletions(-)
 create mode 100644 tests/cases/conformance/es6/destructuring/interfaceSpread.ts
 create mode 100644 tests/cases/conformance/types/spread/objectSpread.ts
 create mode 100644 tests/cases/conformance/types/spread/objectSpreadGeneric.ts
 create mode 100644 tests/cases/conformance/types/spread/objectSpreadNegative.ts
 create mode 100644 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts
 create mode 100644 tests/cases/fourslash/completionListForObjectSpread.ts
 create mode 100644 tests/cases/fourslash/findAllRefsForObjectSpread.ts
 create mode 100644 tests/cases/fourslash/goToDefinitionObjectSpread.ts
 create mode 100644 tests/cases/fourslash/renameObjectSpread.ts

diff --git a/tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts b/tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts
index 2b3192bc9a2c3..1e2bc1e68b433 100644
--- a/tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts
+++ b/tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts
@@ -3,8 +3,5 @@ var {h?} = { h?: 1 };
 var {i}: string | number = { i: 2 };
 var {i1}: string | number| {} = { i1: 2 };
 var { f2: {f21} = { f212: "string" } }: any = undefined;
-var { ...d1 } = {
-    a: 1, b: 1, d1: 9, e: 10
-}
 var {1} = { 1 };
-var {"prop"} = { "prop": 1 };
\ No newline at end of file
+var {"prop"} = { "prop": 1 };
diff --git a/tests/cases/conformance/es6/destructuring/interfaceSpread.ts b/tests/cases/conformance/es6/destructuring/interfaceSpread.ts
new file mode 100644
index 0000000000000..a92a188e1a884
--- /dev/null
+++ b/tests/cases/conformance/es6/destructuring/interfaceSpread.ts
@@ -0,0 +1,8 @@
+interface Congealed<T, U> {
+    ...T
+    ...U
+}
+
+let sandwich: Congealed<{jam: number }, { peanutButter: number }>;
+sandwich.jam;
+sandwich.peanutButter;
diff --git a/tests/cases/conformance/types/spread/objectSpread.ts b/tests/cases/conformance/types/spread/objectSpread.ts
new file mode 100644
index 0000000000000..9828e86f0a6bc
--- /dev/null
+++ b/tests/cases/conformance/types/spread/objectSpread.ts
@@ -0,0 +1,96 @@
+// @target: es5
+let o = { a: 1, b: 'no' }
+let o2 = { b: 'yes', c: true }
+let swap = { a: 'yes', b: -1 };
+
+let addAfter: { a: number, b: string, c: boolean } =
+    { ...o, c: false }
+let addBefore: { a: number, b: string, c: boolean } =
+    { c: false, ...o }
+// Note: ignore still changes the order that properties are printed
+let ignore: { a: number, b: string } =
+    { b: 'ignored', ...o }
+let override: { a: number, b: string } =
+    { ...o, b: 'override' }
+let nested: { a: number, b: boolean, c: string } =
+    { ...{ a: 3, ...{ b: false, c: 'overriden' } }, c: 'whatever' }
+let combined: { a: number, b: string, c: boolean } =
+    { ...o, ...o2 }
+let combinedBefore: { a: number, b: string, c: boolean } =
+    { b: 'ok', ...o, ...o2 }
+let combinedMid: { a: number, b: string, c: boolean } =
+    { ...o, b: 'ok', ...o2 }
+let combinedAfter: { a: number, b: string, c: boolean } =
+    { ...o, ...o2, b: 'ok' }
+let combinedNested: { a: number, b: boolean, c: string, d: string } =
+    { ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } }
+let combinedNestedChangeType: { a: number, b: boolean, c: number } =
+    { ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 }
+let propertyNested: { a: { a: number, b: string } } =
+    { a: { ... o } }
+// accessors don't copy the descriptor
+// (which means that readonly getters become read/write properties)
+let op = { get a () { return 6 } };
+let getter: { a: number, c: number } =
+    { ...op, c: 7 }
+getter.a = 12;
+
+// null and undefined are just skipped
+let spreadNull: { a: number } =
+    { a: 7, ...null }
+let spreadUndefined: { a: number } =
+    { a: 7, ...undefined }
+
+// methods are not enumerable
+class C { p = 1; m() { } }
+let c: C = new C()
+let spreadC: { p: number } = { ...c }
+
+// own methods are enumerable
+let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } };
+cplus.plus();
+
+// new field's type conflicting with existing field is OK
+let changeTypeAfter: { a: string, b: string } =
+    { ...o, a: 'wrong type?' }
+let changeTypeBefore: { a: number, b: string } =
+    { a: 'wrong type?', ...o };
+let changeTypeBoth: { a: string, b: number } =
+    { ...o, ...swap };
+
+// optional
+let definiteBoolean: { sn: boolean };
+let definiteString: { sn: string };
+let optionalString: { sn?: string };
+let optionalNumber: { sn?: number };
+let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
+let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
+let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
+
+// computed property
+let computedFirst: { a: number, b: string, "before everything": number } =
+    { ['before everything']: 12, ...o, b: 'yes' }
+let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
+    { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
+let computedAfter: { a: number, b: string, "at the end": number } =
+    { ...o, b: 'yeah', ['at the end']: 14 }
+// shortcut syntax
+let a = 12;
+let shortCutted: { a: number, b: string } = { ...o, a }
+
+// generics
+function f<T, U>(t: T, u: U): { id: string, ...T, ...U } {
+    return { id: 'id', ...t, ...u };
+}
+let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
+    f({ a: 1, b: 'yes' }, { c: 'no', d: false })
+let overlap: { id: string, a: number, b: string } =
+    f({ a: 1 }, { a: 2, b: 'extra' })
+let overlapConflict: { id:string, a: string } =
+    f({ a: 1 }, { a: 'mismatch' })
+let overwriteId: { id: boolean, a: number, c: number, d: string } =
+    f({ a: 1, id: true }, { c: 1, d: 'no' })
+
+class D { m() { }; q = 2; }
+let classesAreWrong: { id: string, ...C, ...D } =
+    f(new C(), new D())
diff --git a/tests/cases/conformance/types/spread/objectSpreadGeneric.ts b/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
new file mode 100644
index 0000000000000..552142004b70f
--- /dev/null
+++ b/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
@@ -0,0 +1,40 @@
+function f<T, U, V>(t: T, u: U, v: V): void {
+    let o: { ...T, ...U, ...V };
+    const same: { ...T, ...U, ...V } = o; // ok
+    const reversed: { ...V, ...U, ...T } = o; // error, reversed
+    const reversed2: { ...U, ...T, ...V } = o; // error, U and T are still reversed
+    const missingT: { ...U, ...V } = o; // error, missing T
+    const missingU: { ...T, ...V } = o; // error, missing U
+    const missingV: { ...T, ...U } = o; // error, missing V
+    const atEnd: { ...T, ...U, second: string } = { ...t, ...u, second: 'foo' }; // ok
+    const atBeginning: { first: string, ...T, ...U, } = { first: 'foo', ...t, ...u }; // ok
+
+    const emptyTarget: { } = { ...t, ...u } // ok
+    const emptySource: { ...T, ...U } = { }; // error, {} is not assignable to U (or T)
+
+    let optionalNumber: { sn?: number };
+    let optionalString: { sn?: string };
+    let optionalBoolean: { sn?: boolean };
+    const unionCutoff: { ...T, sn?: number | string | boolean } =
+        { ...optionalBoolean, ...t, ...optionalString, ...optionalNumber } // ok
+    unionCutoff.sn; // ok
+    const optionalCutoff = { ...t, ...optionalNumber }; // ok
+    optionalCutoff.sn; // ok
+
+    const interspersed: { first: string, ...T, second: string, ...U, third: string } =
+        { first: '1', ...t, second: '2', ...u, third: '3' }; // ok
+    const interspersedMissingU: { first: string, second: string, ...T, third: string } =
+        { first: '1', ...t, second: '2', ...u, third: '3' }; // error, 'U' is missing
+    const interspersedOrder1: { first: string, ...T, second: string, ...U, third: string, secondsecond: string } =
+        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // ok
+    const interspersedOrder2: { first: string, second: string, secondsecond: string, third: string, ...T, ...U } =
+        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // ok
+
+
+    const mismatchFirst: { first: string, ...T, second: string, ...U, third: string } =
+        { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, 'first' not found
+    const mismatchSecond: { first: string, ...T, second: string, ...U, third: string } =
+        { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, 'second' not found
+    const mismatchLast: { first: string, ...T, second: string, ...U, third: string } =
+        { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, 'third' not found
+}
diff --git a/tests/cases/conformance/types/spread/objectSpreadNegative.ts b/tests/cases/conformance/types/spread/objectSpreadNegative.ts
new file mode 100644
index 0000000000000..4691e45a17df3
--- /dev/null
+++ b/tests/cases/conformance/types/spread/objectSpreadNegative.ts
@@ -0,0 +1,49 @@
+// @target: es5
+let o = { a: 1, b: 'no' }
+
+/// private propagates
+class PrivateOptionalX {
+    private x?: number;
+}
+class PublicX {
+    public x: number;
+}
+let privateOptionalx: PrivateOptionalX;
+let publicx: PublicX;
+let o3 = { ...publicx, ...privateOptionalx };
+let sn: string | number = o3.x; // error, x is private
+let optionalString: { sn?: string };
+let optionalNumber: { sn?: number };
+let allOptional: { sn: string | number } = { ...optionalString, ...optionalNumber };
+// error, 'sn' is optional in source, required in target
+
+// assignability as target
+interface Bool { b: boolean };
+interface Str { s: string };
+let spread: { ...Bool, ...Str } = { s: 'foo' }; // error, missing 'b'
+let b: Bool;
+spread = b; // error, missing 's'
+
+// expressions are not allowed
+let o1 = { ...1 + 1 };
+let o2 = { ...(1 + 1) };
+
+// literal repeats are not allowed, but spread repeats are fine
+let duplicated = { b: 'bad', ...o, b: 'bad', ...o2, b: 'bad' }
+let duplicatedSpread = { ...o, ...o }
+
+// write-only properties get skipped
+let setterOnly = { ...{ set b (bad: number) { } } };
+setterOnly.b = 12; // error, 'b' does not exist
+
+// methods are skipped because they aren't enumerable
+class C { p = 1; m() { } }
+let c: C = new C()
+let spreadC = { ...c }
+spreadC.m(); // error 'm' is not in '{ ... c }'
+
+let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: number) };
+callableConstructableSpread(12); // error, no call signature
+new callableConstructableSpread(12); // error, no construct signature
+
+let callableSpread = { ...publicx, ...(n => n + 1) }; // error, can't spread functions
diff --git a/tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts b/tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts
new file mode 100644
index 0000000000000..47fd787ec9a35
--- /dev/null
+++ b/tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts
@@ -0,0 +1,4 @@
+let o7 = { ...o? };
+let o8 = { ...*o };
+let o9 = { ...matchMedia() { }};
+let o10 = { ...get x() { return 12; }};
diff --git a/tests/cases/fourslash/completionListForObjectSpread.ts b/tests/cases/fourslash/completionListForObjectSpread.ts
new file mode 100644
index 0000000000000..ca96797195c15
--- /dev/null
+++ b/tests/cases/fourslash/completionListForObjectSpread.ts
@@ -0,0 +1,35 @@
+/// <reference path='fourslash.ts'/>
+////let o = { a: 1, b: 'no' }
+////let o2 = { b: 'yes', c: true }
+////let swap = { a: 'yes', b: -1 };
+////let addAfter: { a: number, b: string, c: boolean } =
+////    { ...o, c: false }
+////let addBefore: { a: number, b: string, c: boolean } =
+////    { c: false, ...o }
+////let ignore: { a: number, b: string } =
+////    { b: 'ignored', ...o }
+////ignore./*1*/a;
+////let combinedNestedChangeType: { a: number, b: boolean, c: number } =
+////    { ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 }
+////combinedNestedChangeType./*2*/a;
+////let spreadNull: { a: number } =
+////    { a: 7, ...null }
+////let spreadUndefined: { a: number } =
+////    { a: 7, ...undefined }
+////spreadNull./*3*/a;
+////spreadUndefined./*4*/a;
+goTo.marker('1');
+verify.memberListContains('a', '(property) a: number');
+verify.memberListContains('b', '(property) b: string');
+verify.memberListCount(2);
+goTo.marker('2');
+verify.memberListContains('a', '(property) a: number');
+verify.memberListContains('b', '(property) b: boolean');
+verify.memberListContains('c', '(property) c: number');
+verify.memberListCount(3);
+goTo.marker('3');
+verify.memberListContains('a', '(property) a: number');
+verify.memberListCount(1);
+goTo.marker('4');
+verify.memberListContains('a', '(property) a: number');
+verify.memberListCount(1);
diff --git a/tests/cases/fourslash/findAllRefsForObjectSpread.ts b/tests/cases/fourslash/findAllRefsForObjectSpread.ts
new file mode 100644
index 0000000000000..fe0a7f9c20195
--- /dev/null
+++ b/tests/cases/fourslash/findAllRefsForObjectSpread.ts
@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts'/>
+
+////interface A1 { [|a|]: number };
+////interface A2 { [|a|]?: number };
+////let a12: { ...A1, ...A2 };
+////a12.[|a|];
+const ranges = test.ranges();
+// members of spread types only refer to themselves and the resulting property
+verify.referencesOf(ranges[0], [ranges[0], ranges[2]]);
+verify.referencesOf(ranges[1], [ranges[1], ranges[2]]);
+// but the resulting property refers to everything
+verify.referencesOf(ranges[2], ranges);
diff --git a/tests/cases/fourslash/goToDefinitionObjectSpread.ts b/tests/cases/fourslash/goToDefinitionObjectSpread.ts
new file mode 100644
index 0000000000000..64623c36cb76b
--- /dev/null
+++ b/tests/cases/fourslash/goToDefinitionObjectSpread.ts
@@ -0,0 +1,7 @@
+/// <reference path='fourslash.ts'/>
+
+////interface A1 { /*1*/a: number };
+////interface A2 { /*2*/a?: number };
+////let a12: { ...A1, ...A2 };
+////a12.a/*3*/;
+verify.goToDefinition('3', [ '1', '2' ]);
diff --git a/tests/cases/fourslash/renameObjectSpread.ts b/tests/cases/fourslash/renameObjectSpread.ts
new file mode 100644
index 0000000000000..a2c640361e59c
--- /dev/null
+++ b/tests/cases/fourslash/renameObjectSpread.ts
@@ -0,0 +1,18 @@
+/// <reference path='fourslash.ts'/>
+
+////interface A1 { [|a|]: number };
+////interface A2 { [|a|]?: number };
+////let a12: { ...A1, ...A2 };
+////a12.[|a|];
+const ranges = test.ranges();
+verify.assertHasRanges(ranges);
+
+// A1 unions with A2, so rename A1.a and a12.a
+goTo.position(ranges[0].start);
+verify.renameLocations(/*findInStrings*/ false, /*findInComments*/ false, [ranges[0], ranges[2]]);
+// A1 unions with A2, so rename A2.a and a12.a
+goTo.position(ranges[1].start);
+verify.renameLocations(/*findInStrings*/ false, /*findInComments*/ false, [ranges[1], ranges[2]]);
+// a12.a unions A1.a and A2.a, so rename A1.a, A2.a and a12.a
+goTo.position(ranges[2].start);
+verify.renameLocations(/*findInStrings*/ false, /*findInComments*/ false, [ranges[0], ranges[1], ranges[2]]);

From c8db211d90424abd949805264f724dc4adbbb53e Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 26 Sep 2016 09:33:27 -0700
Subject: [PATCH 005/224] Update baselines

---
 ...ectBindingPatternAndAssignment3.errors.txt |  26 +-
 ...uringObjectBindingPatternAndAssignment3.js |   9 +-
 .../duplicateObjectLiteralProperty.errors.txt |   8 +-
 .../reference/interfaceSpread.errors.txt      |  21 +
 tests/baselines/reference/interfaceSpread.js  |  15 +
 .../lastPropertyInLiteralWins.errors.txt      |   8 +-
 .../reference/memberOverride.errors.txt       |   5 +-
 .../reference/objectLiteralErrors.errors.txt  |   5 +-
 ...tiesErrorFromNotUsingIdentifier.errors.txt |   8 +-
 tests/baselines/reference/objectSpread.js     | 181 ++++++
 .../baselines/reference/objectSpread.symbols  | 369 ++++++++++++
 tests/baselines/reference/objectSpread.types  | 530 ++++++++++++++++++
 .../reference/objectSpreadGeneric.errors.txt  |  80 +++
 .../reference/objectSpreadGeneric.js          |  79 +++
 .../reference/objectSpreadNegative.errors.txt |  93 +++
 .../reference/objectSpreadNegative.js         | 108 ++++
 .../objectSpreadNegativeParse.errors.txt      |  35 ++
 .../reference/objectSpreadNegativeParse.js    |  21 +
 18 files changed, 1569 insertions(+), 32 deletions(-)
 create mode 100644 tests/baselines/reference/interfaceSpread.errors.txt
 create mode 100644 tests/baselines/reference/interfaceSpread.js
 create mode 100644 tests/baselines/reference/objectSpread.js
 create mode 100644 tests/baselines/reference/objectSpread.symbols
 create mode 100644 tests/baselines/reference/objectSpread.types
 create mode 100644 tests/baselines/reference/objectSpreadGeneric.errors.txt
 create mode 100644 tests/baselines/reference/objectSpreadGeneric.js
 create mode 100644 tests/baselines/reference/objectSpreadNegative.errors.txt
 create mode 100644 tests/baselines/reference/objectSpreadNegative.js
 create mode 100644 tests/baselines/reference/objectSpreadNegativeParse.errors.txt
 create mode 100644 tests/baselines/reference/objectSpreadNegativeParse.js

diff --git a/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.errors.txt b/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.errors.txt
index bb4b79987e349..33344b9b5eb00 100644
--- a/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.errors.txt
+++ b/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.errors.txt
@@ -5,16 +5,12 @@ tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAs
 tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(4,6): error TS2459: Type 'string | number | {}' has no property 'i1' and no string index signature.
 tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(5,12): error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
 tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(5,21): error TS2353: Object literal may only specify known properties, and 'f212' does not exist in type '{ f21: any; }'.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(6,7): error TS1180: Property destructuring pattern expected.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(7,5): error TS2353: Object literal may only specify known properties, and 'a' does not exist in type '{ d1: any; }'.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(7,11): error TS2353: Object literal may only specify known properties, and 'b' does not exist in type '{ d1: any; }'.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(7,24): error TS2353: Object literal may only specify known properties, and 'e' does not exist in type '{ d1: any; }'.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(9,7): error TS1005: ':' expected.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(9,15): error TS1005: ':' expected.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(10,12): error TS1005: ':' expected.
+tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(6,7): error TS1005: ':' expected.
+tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(6,15): error TS1005: ':' expected.
+tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(7,12): error TS1005: ':' expected.
 
 
-==== tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts (13 errors) ====
+==== tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts (9 errors) ====
     // Error
     var {h?} = { h?: 1 };
           ~
@@ -33,17 +29,6 @@ tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAs
 !!! error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
                         ~~~~
 !!! error TS2353: Object literal may only specify known properties, and 'f212' does not exist in type '{ f21: any; }'.
-    var { ...d1 } = {
-          ~~~
-!!! error TS1180: Property destructuring pattern expected.
-        a: 1, b: 1, d1: 9, e: 10
-        ~
-!!! error TS2353: Object literal may only specify known properties, and 'a' does not exist in type '{ d1: any; }'.
-              ~
-!!! error TS2353: Object literal may only specify known properties, and 'b' does not exist in type '{ d1: any; }'.
-                           ~
-!!! error TS2353: Object literal may only specify known properties, and 'e' does not exist in type '{ d1: any; }'.
-    }
     var {1} = { 1 };
           ~
 !!! error TS1005: ':' expected.
@@ -51,4 +36,5 @@ tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAs
 !!! error TS1005: ':' expected.
     var {"prop"} = { "prop": 1 };
                ~
-!!! error TS1005: ':' expected.
\ No newline at end of file
+!!! error TS1005: ':' expected.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.js b/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.js
index 77288e6a5427a..0872a71c73bd8 100644
--- a/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.js
+++ b/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.js
@@ -4,11 +4,9 @@ var {h?} = { h?: 1 };
 var {i}: string | number = { i: 2 };
 var {i1}: string | number| {} = { i1: 2 };
 var { f2: {f21} = { f212: "string" } }: any = undefined;
-var { ...d1 } = {
-    a: 1, b: 1, d1: 9, e: 10
-}
 var {1} = { 1 };
-var {"prop"} = { "prop": 1 };
+var {"prop"} = { "prop": 1 };
+
 
 //// [destructuringObjectBindingPatternAndAssignment3.js]
 // Error
@@ -16,8 +14,5 @@ var h = { h: 1 }.h;
 var i = { i: 2 }.i;
 var i1 = { i1: 2 }.i1;
 var _a = undefined.f2, f21 = (_a === void 0 ? { f212: "string" } : _a).f21;
-var d1 = {
-    a: 1, b: 1, d1: 9, e: 10
-}.d1;
 var  = { 1:  }[1];
 var  = { "prop": 1 }["prop"];
diff --git a/tests/baselines/reference/duplicateObjectLiteralProperty.errors.txt b/tests/baselines/reference/duplicateObjectLiteralProperty.errors.txt
index abc56a6f8fce7..926a707122293 100644
--- a/tests/baselines/reference/duplicateObjectLiteralProperty.errors.txt
+++ b/tests/baselines/reference/duplicateObjectLiteralProperty.errors.txt
@@ -1,6 +1,8 @@
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(4,5): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(5,5): error TS2300: Duplicate identifier '\u0061'.
+tests/cases/compiler/duplicateObjectLiteralProperty.ts(5,5): error TS2698: Cannot change type of property 'a' from 'number' to 'string'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(6,5): error TS2300: Duplicate identifier 'a'.
+tests/cases/compiler/duplicateObjectLiteralProperty.ts(6,5): error TS2698: Cannot change type of property 'a' from 'string' to '{ c: number; }'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(8,9): error TS2300: Duplicate identifier '"c"'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(14,9): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(15,9): error TS2300: Duplicate identifier 'a'.
@@ -8,7 +10,7 @@ tests/cases/compiler/duplicateObjectLiteralProperty.ts(16,9): error TS1118: An o
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(16,9): error TS2300: Duplicate identifier 'a'.
 
 
-==== tests/cases/compiler/duplicateObjectLiteralProperty.ts (8 errors) ====
+==== tests/cases/compiler/duplicateObjectLiteralProperty.ts (10 errors) ====
     var x = {
         a: 1,
         b: true, // OK
@@ -18,9 +20,13 @@ tests/cases/compiler/duplicateObjectLiteralProperty.ts(16,9): error TS2300: Dupl
         \u0061: "ss", // Duplicate
         ~~~~~~
 !!! error TS2300: Duplicate identifier '\u0061'.
+        ~~~~~~
+!!! error TS2698: Cannot change type of property 'a' from 'number' to 'string'.
         a: {
         ~
 !!! error TS2300: Duplicate identifier 'a'.
+        ~
+!!! error TS2698: Cannot change type of property 'a' from 'string' to '{ c: number; }'.
             c: 1,
             "c": 56, // Duplicate
             ~~~
diff --git a/tests/baselines/reference/interfaceSpread.errors.txt b/tests/baselines/reference/interfaceSpread.errors.txt
new file mode 100644
index 0000000000000..27aab11491c5a
--- /dev/null
+++ b/tests/baselines/reference/interfaceSpread.errors.txt
@@ -0,0 +1,21 @@
+tests/cases/conformance/es6/destructuring/interfaceSpread.ts(2,5): error TS2699: Interface declaration cannot contain a spread property.
+tests/cases/conformance/es6/destructuring/interfaceSpread.ts(7,10): error TS2339: Property 'jam' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
+tests/cases/conformance/es6/destructuring/interfaceSpread.ts(8,10): error TS2339: Property 'peanutButter' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
+
+
+==== tests/cases/conformance/es6/destructuring/interfaceSpread.ts (3 errors) ====
+    interface Congealed<T, U> {
+        ...T
+        ~~~~
+!!! error TS2699: Interface declaration cannot contain a spread property.
+        ...U
+    }
+    
+    let sandwich: Congealed<{jam: number }, { peanutButter: number }>;
+    sandwich.jam;
+             ~~~
+!!! error TS2339: Property 'jam' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
+    sandwich.peanutButter;
+             ~~~~~~~~~~~~
+!!! error TS2339: Property 'peanutButter' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/interfaceSpread.js b/tests/baselines/reference/interfaceSpread.js
new file mode 100644
index 0000000000000..89f2531436667
--- /dev/null
+++ b/tests/baselines/reference/interfaceSpread.js
@@ -0,0 +1,15 @@
+//// [interfaceSpread.ts]
+interface Congealed<T, U> {
+    ...T
+    ...U
+}
+
+let sandwich: Congealed<{jam: number }, { peanutButter: number }>;
+sandwich.jam;
+sandwich.peanutButter;
+
+
+//// [interfaceSpread.js]
+var sandwich;
+sandwich.jam;
+sandwich.peanutButter;
diff --git a/tests/baselines/reference/lastPropertyInLiteralWins.errors.txt b/tests/baselines/reference/lastPropertyInLiteralWins.errors.txt
index 2b4a694975b4c..c8844f2c5721f 100644
--- a/tests/baselines/reference/lastPropertyInLiteralWins.errors.txt
+++ b/tests/baselines/reference/lastPropertyInLiteralWins.errors.txt
@@ -4,10 +4,12 @@ tests/cases/compiler/lastPropertyInLiteralWins.ts(7,6): error TS2345: Argument o
       Types of parameters 'num' and 'str' are incompatible.
         Type 'string' is not assignable to type 'number'.
 tests/cases/compiler/lastPropertyInLiteralWins.ts(9,5): error TS2300: Duplicate identifier 'thunk'.
+tests/cases/compiler/lastPropertyInLiteralWins.ts(9,5): error TS2698: Cannot change type of property 'thunk' from '(str: string) => void' to '(num: number) => void'.
 tests/cases/compiler/lastPropertyInLiteralWins.ts(14,5): error TS2300: Duplicate identifier 'thunk'.
+tests/cases/compiler/lastPropertyInLiteralWins.ts(14,5): error TS2698: Cannot change type of property 'thunk' from '(num: number) => void' to '(str: string) => void'.
 
 
-==== tests/cases/compiler/lastPropertyInLiteralWins.ts (3 errors) ====
+==== tests/cases/compiler/lastPropertyInLiteralWins.ts (5 errors) ====
     interface Thing {
         thunk: (str: string) => void;
     }
@@ -22,6 +24,8 @@ tests/cases/compiler/lastPropertyInLiteralWins.ts(14,5): error TS2300: Duplicate
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
         ~~~~~
 !!! error TS2300: Duplicate identifier 'thunk'.
+        ~~~~~
+!!! error TS2698: Cannot change type of property 'thunk' from '(str: string) => void' to '(num: number) => void'.
     });
     ~
 !!! error TS2345: Argument of type '{ thunk: (num: number) => void; }' is not assignable to parameter of type 'Thing'.
@@ -35,5 +39,7 @@ tests/cases/compiler/lastPropertyInLiteralWins.ts(14,5): error TS2300: Duplicate
         thunk: (str: string) => {}
         ~~~~~
 !!! error TS2300: Duplicate identifier 'thunk'.
+        ~~~~~
+!!! error TS2698: Cannot change type of property 'thunk' from '(num: number) => void' to '(str: string) => void'.
     });
     
\ No newline at end of file
diff --git a/tests/baselines/reference/memberOverride.errors.txt b/tests/baselines/reference/memberOverride.errors.txt
index 15c4b2ad37bb8..355db0015057f 100644
--- a/tests/baselines/reference/memberOverride.errors.txt
+++ b/tests/baselines/reference/memberOverride.errors.txt
@@ -1,7 +1,8 @@
 tests/cases/compiler/memberOverride.ts(5,5): error TS2300: Duplicate identifier 'a'.
+tests/cases/compiler/memberOverride.ts(5,5): error TS2698: Cannot change type of property 'a' from 'string' to 'number'.
 
 
-==== tests/cases/compiler/memberOverride.ts (1 errors) ====
+==== tests/cases/compiler/memberOverride.ts (2 errors) ====
     // An object initialiser accepts the first definition for the same property with a different type signature
     // Should compile, since the second declaration of a overrides the first
     var x = {
@@ -9,6 +10,8 @@ tests/cases/compiler/memberOverride.ts(5,5): error TS2300: Duplicate identifier
         a: 5
         ~
 !!! error TS2300: Duplicate identifier 'a'.
+        ~
+!!! error TS2698: Cannot change type of property 'a' from 'string' to 'number'.
     }
     
     var n: number = x.a;
\ No newline at end of file
diff --git a/tests/baselines/reference/objectLiteralErrors.errors.txt b/tests/baselines/reference/objectLiteralErrors.errors.txt
index 234ac24a8fdc5..f70f255df05b8 100644
--- a/tests/baselines/reference/objectLiteralErrors.errors.txt
+++ b/tests/baselines/reference/objectLiteralErrors.errors.txt
@@ -1,6 +1,7 @@
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(3,18): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(4,19): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(5,18): error TS2300: Duplicate identifier 'a'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(5,18): error TS2698: Cannot change type of property 'a' from 'number' to 'string'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(6,21): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(7,19): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(8,18): error TS2300: Duplicate identifier ''a''.
@@ -78,7 +79,7 @@ tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(45,16)
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(45,55): error TS2380: 'get' and 'set' accessor must have the same type.
 
 
-==== tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts (78 errors) ====
+==== tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts (79 errors) ====
     
     // Multiple properties with the same name
     var e1 = { a: 0, a: 0 };
@@ -90,6 +91,8 @@ tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(45,55)
     var e3 = { a: 0, a: '' };
                      ~
 !!! error TS2300: Duplicate identifier 'a'.
+                     ~
+!!! error TS2698: Cannot change type of property 'a' from 'number' to 'string'.
     var e4 = { a: true, a: false };
                         ~
 !!! error TS2300: Duplicate identifier 'a'.
diff --git a/tests/baselines/reference/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.errors.txt b/tests/baselines/reference/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.errors.txt
index 5fa8a12e87559..cbe19cab2d25b 100644
--- a/tests/baselines/reference/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.errors.txt
+++ b/tests/baselines/reference/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.errors.txt
@@ -8,12 +8,14 @@ tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPr
 tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(10,10): error TS1005: ':' expected.
 tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(12,1): error TS1005: ':' expected.
 tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(15,6): error TS1005: ':' expected.
+tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(16,5): error TS2698: Cannot change type of property 'a' from 'any' to 'string[]'.
 tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(16,6): error TS1005: ':' expected.
+tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(17,5): error TS2698: Cannot change type of property 'a' from 'string[]' to 'number[]'.
 tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(17,6): error TS1005: ':' expected.
 tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(20,17): error TS1005: ':' expected.
 
 
-==== tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts (13 errors) ====
+==== tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts (15 errors) ====
     // errors
     var y = {
         "stringLiteral",
@@ -50,9 +52,13 @@ tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPr
          ~
 !!! error TS1005: ':' expected.
         a["ss"],
+        ~
+!!! error TS2698: Cannot change type of property 'a' from 'any' to 'string[]'.
          ~
 !!! error TS1005: ':' expected.
         a[1],
+        ~
+!!! error TS2698: Cannot change type of property 'a' from 'string[]' to 'number[]'.
          ~
 !!! error TS1005: ':' expected.
     };
diff --git a/tests/baselines/reference/objectSpread.js b/tests/baselines/reference/objectSpread.js
new file mode 100644
index 0000000000000..a59577fe9dece
--- /dev/null
+++ b/tests/baselines/reference/objectSpread.js
@@ -0,0 +1,181 @@
+//// [objectSpread.ts]
+let o = { a: 1, b: 'no' }
+let o2 = { b: 'yes', c: true }
+let swap = { a: 'yes', b: -1 };
+
+let addAfter: { a: number, b: string, c: boolean } =
+    { ...o, c: false }
+let addBefore: { a: number, b: string, c: boolean } =
+    { c: false, ...o }
+// Note: ignore still changes the order that properties are printed
+let ignore: { a: number, b: string } =
+    { b: 'ignored', ...o }
+let override: { a: number, b: string } =
+    { ...o, b: 'override' }
+let nested: { a: number, b: boolean, c: string } =
+    { ...{ a: 3, ...{ b: false, c: 'overriden' } }, c: 'whatever' }
+let combined: { a: number, b: string, c: boolean } =
+    { ...o, ...o2 }
+let combinedBefore: { a: number, b: string, c: boolean } =
+    { b: 'ok', ...o, ...o2 }
+let combinedMid: { a: number, b: string, c: boolean } =
+    { ...o, b: 'ok', ...o2 }
+let combinedAfter: { a: number, b: string, c: boolean } =
+    { ...o, ...o2, b: 'ok' }
+let combinedNested: { a: number, b: boolean, c: string, d: string } =
+    { ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } }
+let combinedNestedChangeType: { a: number, b: boolean, c: number } =
+    { ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 }
+let propertyNested: { a: { a: number, b: string } } =
+    { a: { ... o } }
+// accessors don't copy the descriptor
+// (which means that readonly getters become read/write properties)
+let op = { get a () { return 6 } };
+let getter: { a: number, c: number } =
+    { ...op, c: 7 }
+getter.a = 12;
+
+// null and undefined are just skipped
+let spreadNull: { a: number } =
+    { a: 7, ...null }
+let spreadUndefined: { a: number } =
+    { a: 7, ...undefined }
+
+// methods are not enumerable
+class C { p = 1; m() { } }
+let c: C = new C()
+let spreadC: { p: number } = { ...c }
+
+// own methods are enumerable
+let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } };
+cplus.plus();
+
+// new field's type conflicting with existing field is OK
+let changeTypeAfter: { a: string, b: string } =
+    { ...o, a: 'wrong type?' }
+let changeTypeBefore: { a: number, b: string } =
+    { a: 'wrong type?', ...o };
+let changeTypeBoth: { a: string, b: number } =
+    { ...o, ...swap };
+
+// optional
+let definiteBoolean: { sn: boolean };
+let definiteString: { sn: string };
+let optionalString: { sn?: string };
+let optionalNumber: { sn?: number };
+let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
+let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
+let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
+
+// computed property
+let computedFirst: { a: number, b: string, "before everything": number } =
+    { ['before everything']: 12, ...o, b: 'yes' }
+let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
+    { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
+let computedAfter: { a: number, b: string, "at the end": number } =
+    { ...o, b: 'yeah', ['at the end']: 14 }
+// shortcut syntax
+let a = 12;
+let shortCutted: { a: number, b: string } = { ...o, a }
+
+// generics
+function f<T, U>(t: T, u: U): { id: string, ...T, ...U } {
+    return { id: 'id', ...t, ...u };
+}
+let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
+    f({ a: 1, b: 'yes' }, { c: 'no', d: false })
+let overlap: { id: string, a: number, b: string } =
+    f({ a: 1 }, { a: 2, b: 'extra' })
+let overlapConflict: { id:string, a: string } =
+    f({ a: 1 }, { a: 'mismatch' })
+let overwriteId: { id: boolean, a: number, c: number, d: string } =
+    f({ a: 1, id: true }, { c: 1, d: 'no' })
+
+class D { m() { }; q = 2; }
+let classesAreWrong: { id: string, ...C, ...D } =
+    f(new C(), new D())
+
+
+//// [objectSpread.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+var o = { a: 1, b: 'no' };
+var o2 = { b: 'yes', c: true };
+var swap = { a: 'yes', b: -1 };
+var addAfter = __assign({}, o, { c: false });
+var addBefore = __assign({ c: false }, o);
+// Note: ignore still changes the order that properties are printed
+var ignore = __assign({ b: 'ignored' }, o);
+var override = __assign({}, o, { b: 'override' });
+var nested = __assign({}, __assign({ a: 3 }, { b: false, c: 'overriden' }), { c: 'whatever' });
+var combined = __assign({}, o, o2);
+var combinedBefore = __assign({ b: 'ok' }, o, o2);
+var combinedMid = __assign({}, o, { b: 'ok' }, o2);
+var combinedAfter = __assign({}, o, o2, { b: 'ok' });
+var combinedNested = __assign({}, __assign({ a: 4 }, { b: false, c: 'overriden' }), { d: 'actually new' }, { a: 5, d: 'maybe new' });
+var combinedNestedChangeType = __assign({}, __assign({ a: 1 }, { b: false, c: 'overriden' }), { c: -1 });
+var propertyNested = __assign({ a: __assign({}, o) });
+// accessors don't copy the descriptor
+// (which means that readonly getters become read/write properties)
+var op = { get a() { return 6; } };
+var getter = __assign({}, op, { c: 7 });
+getter.a = 12;
+// null and undefined are just skipped
+var spreadNull = __assign({ a: 7 }, null);
+var spreadUndefined = __assign({ a: 7 }, undefined);
+// methods are not enumerable
+var C = (function () {
+    function C() {
+        this.p = 1;
+    }
+    C.prototype.m = function () { };
+    return C;
+}());
+var c = new C();
+var spreadC = __assign({}, c);
+// own methods are enumerable
+var cplus = __assign({}, c, { plus: function () { return this.p + 1; } });
+cplus.plus();
+// new field's type conflicting with existing field is OK
+var changeTypeAfter = __assign({}, o, { a: 'wrong type?' });
+var changeTypeBefore = __assign({ a: 'wrong type?' }, o);
+var changeTypeBoth = __assign({}, o, swap);
+// optional
+var definiteBoolean;
+var definiteString;
+var optionalString;
+var optionalNumber;
+var optionalUnionStops = __assign({}, definiteBoolean, definiteString, optionalNumber);
+var optionalUnionDuplicates = __assign({}, definiteBoolean, definiteString, optionalString, optionalNumber);
+var allOptional = __assign({}, optionalString, optionalNumber);
+// computed property
+var computedFirst = __assign((_a = {}, _a['before everything'] = 12, _a), o, { b: 'yes' });
+var computedMiddle = __assign({}, o, (_b = {}, _b['in the middle'] = 13, _b.b = 'maybe?', _b), o2);
+var computedAfter = __assign({}, o, (_c = { b: 'yeah' }, _c['at the end'] = 14, _c));
+// shortcut syntax
+var a = 12;
+var shortCutted = __assign({}, o, { a: a });
+// generics
+function f(t, u) {
+    return __assign({ id: 'id' }, t, u);
+}
+var exclusive = f({ a: 1, b: 'yes' }, { c: 'no', d: false });
+var overlap = f({ a: 1 }, { a: 2, b: 'extra' });
+var overlapConflict = f({ a: 1 }, { a: 'mismatch' });
+var overwriteId = f({ a: 1, id: true }, { c: 1, d: 'no' });
+var D = (function () {
+    function D() {
+        this.q = 2;
+    }
+    D.prototype.m = function () { };
+    ;
+    return D;
+}());
+var classesAreWrong = f(new C(), new D());
+var _a, _b, _c;
diff --git a/tests/baselines/reference/objectSpread.symbols b/tests/baselines/reference/objectSpread.symbols
new file mode 100644
index 0000000000000..001c42804d2b4
--- /dev/null
+++ b/tests/baselines/reference/objectSpread.symbols
@@ -0,0 +1,369 @@
+=== tests/cases/conformance/types/spread/objectSpread.ts ===
+let o = { a: 1, b: 'no' }
+>o : Symbol(o, Decl(objectSpread.ts, 0, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 0, 9))
+>b : Symbol(b, Decl(objectSpread.ts, 0, 15))
+
+let o2 = { b: 'yes', c: true }
+>o2 : Symbol(o2, Decl(objectSpread.ts, 1, 3))
+>b : Symbol(b, Decl(objectSpread.ts, 1, 10))
+>c : Symbol(c, Decl(objectSpread.ts, 1, 20))
+
+let swap = { a: 'yes', b: -1 };
+>swap : Symbol(swap, Decl(objectSpread.ts, 2, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 2, 12))
+>b : Symbol(b, Decl(objectSpread.ts, 2, 22))
+
+let addAfter: { a: number, b: string, c: boolean } =
+>addAfter : Symbol(addAfter, Decl(objectSpread.ts, 4, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 4, 15))
+>b : Symbol(b, Decl(objectSpread.ts, 4, 26))
+>c : Symbol(c, Decl(objectSpread.ts, 4, 37))
+
+    { ...o, c: false }
+>c : Symbol(c, Decl(objectSpread.ts, 5, 11))
+
+let addBefore: { a: number, b: string, c: boolean } =
+>addBefore : Symbol(addBefore, Decl(objectSpread.ts, 6, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 6, 16))
+>b : Symbol(b, Decl(objectSpread.ts, 6, 27))
+>c : Symbol(c, Decl(objectSpread.ts, 6, 38))
+
+    { c: false, ...o }
+>c : Symbol(c, Decl(objectSpread.ts, 7, 5))
+
+// Note: ignore still changes the order that properties are printed
+let ignore: { a: number, b: string } =
+>ignore : Symbol(ignore, Decl(objectSpread.ts, 9, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 9, 13))
+>b : Symbol(b, Decl(objectSpread.ts, 9, 24))
+
+    { b: 'ignored', ...o }
+>b : Symbol(b, Decl(objectSpread.ts, 10, 5))
+
+let override: { a: number, b: string } =
+>override : Symbol(override, Decl(objectSpread.ts, 11, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 11, 15))
+>b : Symbol(b, Decl(objectSpread.ts, 11, 26))
+
+    { ...o, b: 'override' }
+>b : Symbol(b, Decl(objectSpread.ts, 12, 11))
+
+let nested: { a: number, b: boolean, c: string } =
+>nested : Symbol(nested, Decl(objectSpread.ts, 13, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 13, 13))
+>b : Symbol(b, Decl(objectSpread.ts, 13, 24))
+>c : Symbol(c, Decl(objectSpread.ts, 13, 36))
+
+    { ...{ a: 3, ...{ b: false, c: 'overriden' } }, c: 'whatever' }
+>a : Symbol(a, Decl(objectSpread.ts, 14, 10))
+>b : Symbol(b, Decl(objectSpread.ts, 14, 21))
+>c : Symbol(c, Decl(objectSpread.ts, 14, 31))
+>c : Symbol(c, Decl(objectSpread.ts, 14, 51))
+
+let combined: { a: number, b: string, c: boolean } =
+>combined : Symbol(combined, Decl(objectSpread.ts, 15, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 15, 15))
+>b : Symbol(b, Decl(objectSpread.ts, 15, 26))
+>c : Symbol(c, Decl(objectSpread.ts, 15, 37))
+
+    { ...o, ...o2 }
+let combinedBefore: { a: number, b: string, c: boolean } =
+>combinedBefore : Symbol(combinedBefore, Decl(objectSpread.ts, 17, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 17, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 17, 32))
+>c : Symbol(c, Decl(objectSpread.ts, 17, 43))
+
+    { b: 'ok', ...o, ...o2 }
+>b : Symbol(b, Decl(objectSpread.ts, 18, 5))
+
+let combinedMid: { a: number, b: string, c: boolean } =
+>combinedMid : Symbol(combinedMid, Decl(objectSpread.ts, 19, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 19, 18))
+>b : Symbol(b, Decl(objectSpread.ts, 19, 29))
+>c : Symbol(c, Decl(objectSpread.ts, 19, 40))
+
+    { ...o, b: 'ok', ...o2 }
+>b : Symbol(b, Decl(objectSpread.ts, 20, 11))
+
+let combinedAfter: { a: number, b: string, c: boolean } =
+>combinedAfter : Symbol(combinedAfter, Decl(objectSpread.ts, 21, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 21, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 21, 31))
+>c : Symbol(c, Decl(objectSpread.ts, 21, 42))
+
+    { ...o, ...o2, b: 'ok' }
+>b : Symbol(b, Decl(objectSpread.ts, 22, 18))
+
+let combinedNested: { a: number, b: boolean, c: string, d: string } =
+>combinedNested : Symbol(combinedNested, Decl(objectSpread.ts, 23, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 23, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 23, 32))
+>c : Symbol(c, Decl(objectSpread.ts, 23, 44))
+>d : Symbol(d, Decl(objectSpread.ts, 23, 55))
+
+    { ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } }
+>a : Symbol(a, Decl(objectSpread.ts, 24, 10))
+>b : Symbol(b, Decl(objectSpread.ts, 24, 21))
+>c : Symbol(c, Decl(objectSpread.ts, 24, 31))
+>d : Symbol(d, Decl(objectSpread.ts, 24, 51))
+>a : Symbol(a, Decl(objectSpread.ts, 24, 75))
+>d : Symbol(d, Decl(objectSpread.ts, 24, 81))
+
+let combinedNestedChangeType: { a: number, b: boolean, c: number } =
+>combinedNestedChangeType : Symbol(combinedNestedChangeType, Decl(objectSpread.ts, 25, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 25, 31))
+>b : Symbol(b, Decl(objectSpread.ts, 25, 42))
+>c : Symbol(c, Decl(objectSpread.ts, 25, 54))
+
+    { ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 }
+>a : Symbol(a, Decl(objectSpread.ts, 26, 10))
+>b : Symbol(b, Decl(objectSpread.ts, 26, 21))
+>c : Symbol(c, Decl(objectSpread.ts, 26, 31))
+>c : Symbol(c, Decl(objectSpread.ts, 26, 51))
+
+let propertyNested: { a: { a: number, b: string } } =
+>propertyNested : Symbol(propertyNested, Decl(objectSpread.ts, 27, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 27, 21))
+>a : Symbol(a, Decl(objectSpread.ts, 27, 26))
+>b : Symbol(b, Decl(objectSpread.ts, 27, 37))
+
+    { a: { ... o } }
+>a : Symbol(a, Decl(objectSpread.ts, 28, 5))
+
+// accessors don't copy the descriptor
+// (which means that readonly getters become read/write properties)
+let op = { get a () { return 6 } };
+>op : Symbol(op, Decl(objectSpread.ts, 31, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 31, 10))
+
+let getter: { a: number, c: number } =
+>getter : Symbol(getter, Decl(objectSpread.ts, 32, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 32, 13))
+>c : Symbol(c, Decl(objectSpread.ts, 32, 24))
+
+    { ...op, c: 7 }
+>c : Symbol(c, Decl(objectSpread.ts, 33, 12))
+
+getter.a = 12;
+>getter.a : Symbol(a, Decl(objectSpread.ts, 32, 13))
+>getter : Symbol(getter, Decl(objectSpread.ts, 32, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 32, 13))
+
+// null and undefined are just skipped
+let spreadNull: { a: number } =
+>spreadNull : Symbol(spreadNull, Decl(objectSpread.ts, 37, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 37, 17))
+
+    { a: 7, ...null }
+>a : Symbol(a, Decl(objectSpread.ts, 38, 5))
+
+let spreadUndefined: { a: number } =
+>spreadUndefined : Symbol(spreadUndefined, Decl(objectSpread.ts, 39, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 39, 22))
+
+    { a: 7, ...undefined }
+>a : Symbol(a, Decl(objectSpread.ts, 40, 5))
+
+// methods are not enumerable
+class C { p = 1; m() { } }
+>C : Symbol(C, Decl(objectSpread.ts, 40, 26))
+>p : Symbol(C.p, Decl(objectSpread.ts, 43, 9))
+>m : Symbol(C.m, Decl(objectSpread.ts, 43, 16))
+
+let c: C = new C()
+>c : Symbol(c, Decl(objectSpread.ts, 44, 3))
+>C : Symbol(C, Decl(objectSpread.ts, 40, 26))
+>C : Symbol(C, Decl(objectSpread.ts, 40, 26))
+
+let spreadC: { p: number } = { ...c }
+>spreadC : Symbol(spreadC, Decl(objectSpread.ts, 45, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 45, 14))
+
+// own methods are enumerable
+let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } };
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 48, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 48, 12))
+>plus : Symbol(plus, Decl(objectSpread.ts, 48, 23))
+>plus : Symbol(plus, Decl(objectSpread.ts, 48, 48))
+
+cplus.plus();
+>cplus.plus : Symbol(plus, Decl(objectSpread.ts, 48, 23))
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 48, 3))
+>plus : Symbol(plus, Decl(objectSpread.ts, 48, 23))
+
+// new field's type conflicting with existing field is OK
+let changeTypeAfter: { a: string, b: string } =
+>changeTypeAfter : Symbol(changeTypeAfter, Decl(objectSpread.ts, 52, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 52, 22))
+>b : Symbol(b, Decl(objectSpread.ts, 52, 33))
+
+    { ...o, a: 'wrong type?' }
+>a : Symbol(a, Decl(objectSpread.ts, 53, 11))
+
+let changeTypeBefore: { a: number, b: string } =
+>changeTypeBefore : Symbol(changeTypeBefore, Decl(objectSpread.ts, 54, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 54, 23))
+>b : Symbol(b, Decl(objectSpread.ts, 54, 34))
+
+    { a: 'wrong type?', ...o };
+>a : Symbol(a, Decl(objectSpread.ts, 55, 5))
+
+let changeTypeBoth: { a: string, b: number } =
+>changeTypeBoth : Symbol(changeTypeBoth, Decl(objectSpread.ts, 56, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 56, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 56, 32))
+
+    { ...o, ...swap };
+
+// optional
+let definiteBoolean: { sn: boolean };
+>definiteBoolean : Symbol(definiteBoolean, Decl(objectSpread.ts, 60, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 60, 22))
+
+let definiteString: { sn: string };
+>definiteString : Symbol(definiteString, Decl(objectSpread.ts, 61, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 61, 21))
+
+let optionalString: { sn?: string };
+>optionalString : Symbol(optionalString, Decl(objectSpread.ts, 62, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 62, 21))
+
+let optionalNumber: { sn?: number };
+>optionalNumber : Symbol(optionalNumber, Decl(objectSpread.ts, 63, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 63, 21))
+
+let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
+>optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpread.ts, 64, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 64, 25))
+
+let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
+>optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpread.ts, 65, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 65, 30))
+
+let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
+>allOptional : Symbol(allOptional, Decl(objectSpread.ts, 66, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 66, 18))
+
+// computed property
+let computedFirst: { a: number, b: string, "before everything": number } =
+>computedFirst : Symbol(computedFirst, Decl(objectSpread.ts, 69, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 69, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 69, 31))
+
+    { ['before everything']: 12, ...o, b: 'yes' }
+>'before everything' : Symbol(['before everything'], Decl(objectSpread.ts, 70, 5))
+>b : Symbol(b, Decl(objectSpread.ts, 70, 38))
+
+let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
+>computedMiddle : Symbol(computedMiddle, Decl(objectSpread.ts, 71, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 71, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 71, 32))
+>c : Symbol(c, Decl(objectSpread.ts, 71, 43))
+
+    { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
+>'in the middle' : Symbol(['in the middle'], Decl(objectSpread.ts, 72, 11))
+>b : Symbol(b, Decl(objectSpread.ts, 72, 34))
+
+let computedAfter: { a: number, b: string, "at the end": number } =
+>computedAfter : Symbol(computedAfter, Decl(objectSpread.ts, 73, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 73, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 73, 31))
+
+    { ...o, b: 'yeah', ['at the end']: 14 }
+>b : Symbol(b, Decl(objectSpread.ts, 74, 11))
+>'at the end' : Symbol(['at the end'], Decl(objectSpread.ts, 74, 22))
+
+// shortcut syntax
+let a = 12;
+>a : Symbol(a, Decl(objectSpread.ts, 76, 3))
+
+let shortCutted: { a: number, b: string } = { ...o, a }
+>shortCutted : Symbol(shortCutted, Decl(objectSpread.ts, 77, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 77, 18))
+>b : Symbol(b, Decl(objectSpread.ts, 77, 29))
+>a : Symbol(a, Decl(objectSpread.ts, 77, 51))
+
+// generics
+function f<T, U>(t: T, u: U): { id: string, ...T, ...U } {
+>f : Symbol(f, Decl(objectSpread.ts, 77, 55))
+>T : Symbol(T, Decl(objectSpread.ts, 80, 11))
+>U : Symbol(U, Decl(objectSpread.ts, 80, 13))
+>t : Symbol(t, Decl(objectSpread.ts, 80, 17))
+>T : Symbol(T, Decl(objectSpread.ts, 80, 11))
+>u : Symbol(u, Decl(objectSpread.ts, 80, 22))
+>U : Symbol(U, Decl(objectSpread.ts, 80, 13))
+>id : Symbol(id, Decl(objectSpread.ts, 80, 31))
+>T : Symbol(T, Decl(objectSpread.ts, 80, 11))
+>U : Symbol(U, Decl(objectSpread.ts, 80, 13))
+
+    return { id: 'id', ...t, ...u };
+>id : Symbol(id, Decl(objectSpread.ts, 81, 12))
+}
+let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
+>exclusive : Symbol(exclusive, Decl(objectSpread.ts, 83, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 83, 16))
+>a : Symbol(a, Decl(objectSpread.ts, 83, 28))
+>b : Symbol(b, Decl(objectSpread.ts, 83, 39))
+>c : Symbol(c, Decl(objectSpread.ts, 83, 50))
+>d : Symbol(d, Decl(objectSpread.ts, 83, 61))
+
+    f({ a: 1, b: 'yes' }, { c: 'no', d: false })
+>f : Symbol(f, Decl(objectSpread.ts, 77, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 84, 7))
+>b : Symbol(b, Decl(objectSpread.ts, 84, 13))
+>c : Symbol(c, Decl(objectSpread.ts, 84, 27))
+>d : Symbol(d, Decl(objectSpread.ts, 84, 36))
+
+let overlap: { id: string, a: number, b: string } =
+>overlap : Symbol(overlap, Decl(objectSpread.ts, 85, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 85, 14))
+>a : Symbol(a, Decl(objectSpread.ts, 85, 26))
+>b : Symbol(b, Decl(objectSpread.ts, 85, 37))
+
+    f({ a: 1 }, { a: 2, b: 'extra' })
+>f : Symbol(f, Decl(objectSpread.ts, 77, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 86, 7))
+>a : Symbol(a, Decl(objectSpread.ts, 86, 17))
+>b : Symbol(b, Decl(objectSpread.ts, 86, 23))
+
+let overlapConflict: { id:string, a: string } =
+>overlapConflict : Symbol(overlapConflict, Decl(objectSpread.ts, 87, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 87, 22))
+>a : Symbol(a, Decl(objectSpread.ts, 87, 33))
+
+    f({ a: 1 }, { a: 'mismatch' })
+>f : Symbol(f, Decl(objectSpread.ts, 77, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 88, 7))
+>a : Symbol(a, Decl(objectSpread.ts, 88, 17))
+
+let overwriteId: { id: boolean, a: number, c: number, d: string } =
+>overwriteId : Symbol(overwriteId, Decl(objectSpread.ts, 89, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 89, 18))
+>a : Symbol(a, Decl(objectSpread.ts, 89, 31))
+>c : Symbol(c, Decl(objectSpread.ts, 89, 42))
+>d : Symbol(d, Decl(objectSpread.ts, 89, 53))
+
+    f({ a: 1, id: true }, { c: 1, d: 'no' })
+>f : Symbol(f, Decl(objectSpread.ts, 77, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 90, 7))
+>id : Symbol(id, Decl(objectSpread.ts, 90, 13))
+>c : Symbol(c, Decl(objectSpread.ts, 90, 27))
+>d : Symbol(d, Decl(objectSpread.ts, 90, 33))
+
+class D { m() { }; q = 2; }
+>D : Symbol(D, Decl(objectSpread.ts, 90, 44))
+>m : Symbol(D.m, Decl(objectSpread.ts, 92, 9))
+>q : Symbol(D.q, Decl(objectSpread.ts, 92, 18))
+
+let classesAreWrong: { id: string, ...C, ...D } =
+>classesAreWrong : Symbol(classesAreWrong, Decl(objectSpread.ts, 93, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 93, 22))
+>C : Symbol(C, Decl(objectSpread.ts, 40, 26))
+>D : Symbol(D, Decl(objectSpread.ts, 90, 44))
+
+    f(new C(), new D())
+>f : Symbol(f, Decl(objectSpread.ts, 77, 55))
+>C : Symbol(C, Decl(objectSpread.ts, 40, 26))
+>D : Symbol(D, Decl(objectSpread.ts, 90, 44))
+
diff --git a/tests/baselines/reference/objectSpread.types b/tests/baselines/reference/objectSpread.types
new file mode 100644
index 0000000000000..1a053a22670c0
--- /dev/null
+++ b/tests/baselines/reference/objectSpread.types
@@ -0,0 +1,530 @@
+=== tests/cases/conformance/types/spread/objectSpread.ts ===
+let o = { a: 1, b: 'no' }
+>o : { a: number; b: string; }
+>{ a: 1, b: 'no' } : { a: number; b: string; }
+>a : number
+>1 : 1
+>b : string
+>'no' : "no"
+
+let o2 = { b: 'yes', c: true }
+>o2 : { b: string; c: boolean; }
+>{ b: 'yes', c: true } : { b: string; c: boolean; }
+>b : string
+>'yes' : "yes"
+>c : boolean
+>true : true
+
+let swap = { a: 'yes', b: -1 };
+>swap : { a: string; b: number; }
+>{ a: 'yes', b: -1 } : { a: string; b: number; }
+>a : string
+>'yes' : "yes"
+>b : number
+>-1 : -1
+>1 : 1
+
+let addAfter: { a: number, b: string, c: boolean } =
+>addAfter : { a: number; b: string; c: boolean; }
+>a : number
+>b : string
+>c : boolean
+
+    { ...o, c: false }
+>{ ...o, c: false } : { ...{ a: number; b: string; }; c: false; }
+>o : any
+>c : boolean
+>false : false
+
+let addBefore: { a: number, b: string, c: boolean } =
+>addBefore : { a: number; b: string; c: boolean; }
+>a : number
+>b : string
+>c : boolean
+
+    { c: false, ...o }
+>{ c: false, ...o } : { c: false; ...{ a: number; b: string; } }
+>c : boolean
+>false : false
+>o : any
+
+// Note: ignore still changes the order that properties are printed
+let ignore: { a: number, b: string } =
+>ignore : { a: number; b: string; }
+>a : number
+>b : string
+
+    { b: 'ignored', ...o }
+>{ b: 'ignored', ...o } : { b: string; ...{ a: number; b: string; } }
+>b : string
+>'ignored' : "ignored"
+>o : any
+
+let override: { a: number, b: string } =
+>override : { a: number; b: string; }
+>a : number
+>b : string
+
+    { ...o, b: 'override' }
+>{ ...o, b: 'override' } : { ...{ a: number; b: string; }; b: string; }
+>o : any
+>b : string
+>'override' : "override"
+
+let nested: { a: number, b: boolean, c: string } =
+>nested : { a: number; b: boolean; c: string; }
+>a : number
+>b : boolean
+>c : string
+
+    { ...{ a: 3, ...{ b: false, c: 'overriden' } }, c: 'whatever' }
+>{ ...{ a: 3, ...{ b: false, c: 'overriden' } }, c: 'whatever' } : { ...{ a: number; ...{ b: boolean; c: string; } }; c: string; }
+>{ a: 3, ...{ b: false, c: 'overriden' } } : { a: number; ...{ b: boolean; c: string; } }
+>a : number
+>3 : 3
+>{ b: false, c: 'overriden' } : { b: boolean; c: string; }
+>b : boolean
+>false : false
+>c : string
+>'overriden' : "overriden"
+>c : string
+>'whatever' : "whatever"
+
+let combined: { a: number, b: string, c: boolean } =
+>combined : { a: number; b: string; c: boolean; }
+>a : number
+>b : string
+>c : boolean
+
+    { ...o, ...o2 }
+>{ ...o, ...o2 } : { ...{ a: number; b: string; }; ...{ b: string; c: boolean; } }
+>o : any
+>o2 : any
+
+let combinedBefore: { a: number, b: string, c: boolean } =
+>combinedBefore : { a: number; b: string; c: boolean; }
+>a : number
+>b : string
+>c : boolean
+
+    { b: 'ok', ...o, ...o2 }
+>{ b: 'ok', ...o, ...o2 } : { b: string; ...{ a: number; b: string; }; ...{ b: string; c: boolean; } }
+>b : string
+>'ok' : "ok"
+>o : any
+>o2 : any
+
+let combinedMid: { a: number, b: string, c: boolean } =
+>combinedMid : { a: number; b: string; c: boolean; }
+>a : number
+>b : string
+>c : boolean
+
+    { ...o, b: 'ok', ...o2 }
+>{ ...o, b: 'ok', ...o2 } : { ...{ a: number; b: string; }; b: string; ...{ b: string; c: boolean; } }
+>o : any
+>b : string
+>'ok' : "ok"
+>o2 : any
+
+let combinedAfter: { a: number, b: string, c: boolean } =
+>combinedAfter : { a: number; b: string; c: boolean; }
+>a : number
+>b : string
+>c : boolean
+
+    { ...o, ...o2, b: 'ok' }
+>{ ...o, ...o2, b: 'ok' } : { ...{ a: number; b: string; }; ...{ b: string; c: boolean; }; b: string; }
+>o : any
+>o2 : any
+>b : string
+>'ok' : "ok"
+
+let combinedNested: { a: number, b: boolean, c: string, d: string } =
+>combinedNested : { a: number; b: boolean; c: string; d: string; }
+>a : number
+>b : boolean
+>c : string
+>d : string
+
+    { ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } }
+>{ ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } } : { ...{ a: number; ...{ b: boolean; c: string; } }; d: string; ...{ a: number; d: string; } }
+>{ a: 4, ...{ b: false, c: 'overriden' } } : { a: number; ...{ b: boolean; c: string; } }
+>a : number
+>4 : 4
+>{ b: false, c: 'overriden' } : { b: boolean; c: string; }
+>b : boolean
+>false : false
+>c : string
+>'overriden' : "overriden"
+>d : string
+>'actually new' : "actually new"
+>{ a: 5, d: 'maybe new' } : { a: number; d: string; }
+>a : number
+>5 : 5
+>d : string
+>'maybe new' : "maybe new"
+
+let combinedNestedChangeType: { a: number, b: boolean, c: number } =
+>combinedNestedChangeType : { a: number; b: boolean; c: number; }
+>a : number
+>b : boolean
+>c : number
+
+    { ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 }
+>{ ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 } : { ...{ a: number; ...{ b: boolean; c: string; } }; c: number; }
+>{ a: 1, ...{ b: false, c: 'overriden' } } : { a: number; ...{ b: boolean; c: string; } }
+>a : number
+>1 : 1
+>{ b: false, c: 'overriden' } : { b: boolean; c: string; }
+>b : boolean
+>false : false
+>c : string
+>'overriden' : "overriden"
+>c : number
+>-1 : -1
+>1 : 1
+
+let propertyNested: { a: { a: number, b: string } } =
+>propertyNested : { a: { a: number; b: string; }; }
+>a : { a: number; b: string; }
+>a : number
+>b : string
+
+    { a: { ... o } }
+>{ a: { ... o } } : { a: { ...{ a: number; b: string; } }; }
+>a : { ...{ a: number; b: string; } }
+>{ ... o } : { ...{ a: number; b: string; } }
+>o : any
+
+// accessors don't copy the descriptor
+// (which means that readonly getters become read/write properties)
+let op = { get a () { return 6 } };
+>op : { readonly a: number; }
+>{ get a () { return 6 } } : { readonly a: number; }
+>a : number
+>6 : 6
+
+let getter: { a: number, c: number } =
+>getter : { a: number; c: number; }
+>a : number
+>c : number
+
+    { ...op, c: 7 }
+>{ ...op, c: 7 } : { ...{ readonly a: number; }; c: number; }
+>op : any
+>c : number
+>7 : 7
+
+getter.a = 12;
+>getter.a = 12 : 12
+>getter.a : number
+>getter : { a: number; c: number; }
+>a : number
+>12 : 12
+
+// null and undefined are just skipped
+let spreadNull: { a: number } =
+>spreadNull : { a: number; }
+>a : number
+
+    { a: 7, ...null }
+>{ a: 7, ...null } : { a: number; }
+>a : number
+>7 : 7
+>null : null
+
+let spreadUndefined: { a: number } =
+>spreadUndefined : { a: number; }
+>a : number
+
+    { a: 7, ...undefined }
+>{ a: 7, ...undefined } : { a: number; }
+>a : number
+>7 : 7
+>undefined : any
+
+// methods are not enumerable
+class C { p = 1; m() { } }
+>C : C
+>p : number
+>1 : 1
+>m : () => void
+
+let c: C = new C()
+>c : C
+>C : C
+>new C() : C
+>C : typeof C
+
+let spreadC: { p: number } = { ...c }
+>spreadC : { p: number; }
+>p : number
+>{ ...c } : { ...C }
+>c : any
+
+// own methods are enumerable
+let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } };
+>cplus : { p: number; plus(): void; }
+>p : number
+>plus : () => void
+>{ ...c, plus() { return this.p + 1; } } : { ...C; plus(): any; }
+>c : any
+>plus : () => any
+>this.p + 1 : any
+>this.p : any
+>this : any
+>p : any
+>1 : 1
+
+cplus.plus();
+>cplus.plus() : void
+>cplus.plus : () => void
+>cplus : { p: number; plus(): void; }
+>plus : () => void
+
+// new field's type conflicting with existing field is OK
+let changeTypeAfter: { a: string, b: string } =
+>changeTypeAfter : { a: string; b: string; }
+>a : string
+>b : string
+
+    { ...o, a: 'wrong type?' }
+>{ ...o, a: 'wrong type?' } : { ...{ a: number; b: string; }; a: string; }
+>o : any
+>a : string
+>'wrong type?' : "wrong type?"
+
+let changeTypeBefore: { a: number, b: string } =
+>changeTypeBefore : { a: number; b: string; }
+>a : number
+>b : string
+
+    { a: 'wrong type?', ...o };
+>{ a: 'wrong type?', ...o } : { a: string; ...{ a: number; b: string; } }
+>a : string
+>'wrong type?' : "wrong type?"
+>o : any
+
+let changeTypeBoth: { a: string, b: number } =
+>changeTypeBoth : { a: string; b: number; }
+>a : string
+>b : number
+
+    { ...o, ...swap };
+>{ ...o, ...swap } : { ...{ a: number; b: string; }; ...{ a: string; b: number; } }
+>o : any
+>swap : any
+
+// optional
+let definiteBoolean: { sn: boolean };
+>definiteBoolean : { sn: boolean; }
+>sn : boolean
+
+let definiteString: { sn: string };
+>definiteString : { sn: string; }
+>sn : string
+
+let optionalString: { sn?: string };
+>optionalString : { sn?: string; }
+>sn : string
+
+let optionalNumber: { sn?: number };
+>optionalNumber : { sn?: number; }
+>sn : number
+
+let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
+>optionalUnionStops : { sn: string | number | boolean; }
+>sn : string | number | boolean
+>{ ...definiteBoolean, ...definiteString, ...optionalNumber } : { ...{ sn: boolean; }; ...{ sn: string; }; ...{ sn?: number; } }
+>definiteBoolean : any
+>definiteString : any
+>optionalNumber : any
+
+let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
+>optionalUnionDuplicates : { sn: string | number; }
+>sn : string | number
+>{ ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber } : { ...{ sn: boolean; }; ...{ sn: string; }; ...{ sn?: string; }; ...{ sn?: number; } }
+>definiteBoolean : any
+>definiteString : any
+>optionalString : any
+>optionalNumber : any
+
+let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
+>allOptional : { sn?: string | number; }
+>sn : string | number
+>{ ...optionalString, ...optionalNumber } : { ...{ sn?: string; }; ...{ sn?: number; } }
+>optionalString : any
+>optionalNumber : any
+
+// computed property
+let computedFirst: { a: number, b: string, "before everything": number } =
+>computedFirst : { a: number; b: string; "before everything": number; }
+>a : number
+>b : string
+
+    { ['before everything']: 12, ...o, b: 'yes' }
+>{ ['before everything']: 12, ...o, b: 'yes' } : { ['before everything']: number; ...{ a: number; b: string; }; b: string; }
+>'before everything' : "before everything"
+>12 : 12
+>o : any
+>b : string
+>'yes' : "yes"
+
+let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
+>computedMiddle : { a: number; b: string; c: boolean; "in the middle": number; }
+>a : number
+>b : string
+>c : boolean
+
+    { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
+>{ ...o, ['in the middle']: 13, b: 'maybe?', ...o2 } : { ...{ a: number; b: string; }; ['in the middle']: number; b: string; ...{ b: string; c: boolean; } }
+>o : any
+>'in the middle' : "in the middle"
+>13 : 13
+>b : string
+>'maybe?' : "maybe?"
+>o2 : any
+
+let computedAfter: { a: number, b: string, "at the end": number } =
+>computedAfter : { a: number; b: string; "at the end": number; }
+>a : number
+>b : string
+
+    { ...o, b: 'yeah', ['at the end']: 14 }
+>{ ...o, b: 'yeah', ['at the end']: 14 } : { ...{ a: number; b: string; }; b: string; ['at the end']: number; }
+>o : any
+>b : string
+>'yeah' : "yeah"
+>'at the end' : "at the end"
+>14 : 14
+
+// shortcut syntax
+let a = 12;
+>a : number
+>12 : 12
+
+let shortCutted: { a: number, b: string } = { ...o, a }
+>shortCutted : { a: number; b: string; }
+>a : number
+>b : string
+>{ ...o, a } : { ...{ a: number; b: string; }; a: number; }
+>o : any
+>a : number
+
+// generics
+function f<T, U>(t: T, u: U): { id: string, ...T, ...U } {
+>f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
+>T : T
+>U : U
+>t : T
+>T : T
+>u : U
+>U : U
+>id : string
+>T : T
+>U : U
+
+    return { id: 'id', ...t, ...u };
+>{ id: 'id', ...t, ...u } : { id: string; ...T; ...U }
+>id : string
+>'id' : "id"
+>t : any
+>u : any
+}
+let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
+>exclusive : { id: string; a: number; b: string; c: string; d: boolean; }
+>id : string
+>a : number
+>b : string
+>c : string
+>d : boolean
+
+    f({ a: 1, b: 'yes' }, { c: 'no', d: false })
+>f({ a: 1, b: 'yes' }, { c: 'no', d: false }) : { id: string; ...{ a: number; b: string; }; ...{ c: string; d: boolean; } }
+>f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
+>{ a: 1, b: 'yes' } : { a: number; b: string; }
+>a : number
+>1 : 1
+>b : string
+>'yes' : "yes"
+>{ c: 'no', d: false } : { c: string; d: false; }
+>c : string
+>'no' : "no"
+>d : boolean
+>false : false
+
+let overlap: { id: string, a: number, b: string } =
+>overlap : { id: string; a: number; b: string; }
+>id : string
+>a : number
+>b : string
+
+    f({ a: 1 }, { a: 2, b: 'extra' })
+>f({ a: 1 }, { a: 2, b: 'extra' }) : { id: string; ...{ a: number; }; ...{ a: number; b: string; } }
+>f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
+>{ a: 1 } : { a: number; }
+>a : number
+>1 : 1
+>{ a: 2, b: 'extra' } : { a: number; b: string; }
+>a : number
+>2 : 2
+>b : string
+>'extra' : "extra"
+
+let overlapConflict: { id:string, a: string } =
+>overlapConflict : { id: string; a: string; }
+>id : string
+>a : string
+
+    f({ a: 1 }, { a: 'mismatch' })
+>f({ a: 1 }, { a: 'mismatch' }) : { id: string; ...{ a: number; }; ...{ a: string; } }
+>f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
+>{ a: 1 } : { a: number; }
+>a : number
+>1 : 1
+>{ a: 'mismatch' } : { a: string; }
+>a : string
+>'mismatch' : "mismatch"
+
+let overwriteId: { id: boolean, a: number, c: number, d: string } =
+>overwriteId : { id: boolean; a: number; c: number; d: string; }
+>id : boolean
+>a : number
+>c : number
+>d : string
+
+    f({ a: 1, id: true }, { c: 1, d: 'no' })
+>f({ a: 1, id: true }, { c: 1, d: 'no' }) : { id: string; ...{ a: number; id: boolean; }; ...{ c: number; d: string; } }
+>f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
+>{ a: 1, id: true } : { a: number; id: true; }
+>a : number
+>1 : 1
+>id : boolean
+>true : true
+>{ c: 1, d: 'no' } : { c: number; d: string; }
+>c : number
+>1 : 1
+>d : string
+>'no' : "no"
+
+class D { m() { }; q = 2; }
+>D : D
+>m : () => void
+>q : number
+>2 : 2
+
+let classesAreWrong: { id: string, ...C, ...D } =
+>classesAreWrong : { id: string; ...C; ...D }
+>id : string
+>C : C
+>D : D
+
+    f(new C(), new D())
+>f(new C(), new D()) : { id: string; ...C; ...D }
+>f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
+>new C() : C
+>C : typeof C
+>new D() : D
+>D : typeof D
+
diff --git a/tests/baselines/reference/objectSpreadGeneric.errors.txt b/tests/baselines/reference/objectSpreadGeneric.errors.txt
new file mode 100644
index 0000000000000..16dfc835d2607
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadGeneric.errors.txt
@@ -0,0 +1,80 @@
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(4,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...V; ...U; ...T }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(5,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...T; ...V }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(6,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...V }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(7,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...V }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(8,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...U }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(13,11): error TS2322: Type '{}' is not assignable to type '{ ...T; ...U }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(26,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; second: string; ...T; third: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(34,11): error TS2322: Type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+  Property 'first' is missing in type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(36,11): error TS2322: Type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+  Property 'second' is missing in type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(38,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+  Property 'third' is missing in type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }'.
+
+
+==== tests/cases/conformance/types/spread/objectSpreadGeneric.ts (10 errors) ====
+    function f<T, U, V>(t: T, u: U, v: V): void {
+        let o: { ...T, ...U, ...V };
+        const same: { ...T, ...U, ...V } = o; // ok
+        const reversed: { ...V, ...U, ...T } = o; // error, reversed
+              ~~~~~~~~
+!!! error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...V; ...U; ...T }'.
+        const reversed2: { ...U, ...T, ...V } = o; // error, U and T are still reversed
+              ~~~~~~~~~
+!!! error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...T; ...V }'.
+        const missingT: { ...U, ...V } = o; // error, missing T
+              ~~~~~~~~
+!!! error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...V }'.
+        const missingU: { ...T, ...V } = o; // error, missing U
+              ~~~~~~~~
+!!! error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...V }'.
+        const missingV: { ...T, ...U } = o; // error, missing V
+              ~~~~~~~~
+!!! error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...U }'.
+        const atEnd: { ...T, ...U, second: string } = { ...t, ...u, second: 'foo' }; // ok
+        const atBeginning: { first: string, ...T, ...U, } = { first: 'foo', ...t, ...u }; // ok
+    
+        const emptyTarget: { } = { ...t, ...u } // ok
+        const emptySource: { ...T, ...U } = { }; // error, {} is not assignable to U (or T)
+              ~~~~~~~~~~~
+!!! error TS2322: Type '{}' is not assignable to type '{ ...T; ...U }'.
+    
+        let optionalNumber: { sn?: number };
+        let optionalString: { sn?: string };
+        let optionalBoolean: { sn?: boolean };
+        const unionCutoff: { ...T, sn?: number | string | boolean } =
+            { ...optionalBoolean, ...t, ...optionalString, ...optionalNumber } // ok
+        unionCutoff.sn; // ok
+        const optionalCutoff = { ...t, ...optionalNumber }; // ok
+        optionalCutoff.sn; // ok
+    
+        const interspersed: { first: string, ...T, second: string, ...U, third: string } =
+            { first: '1', ...t, second: '2', ...u, third: '3' }; // ok
+        const interspersedMissingU: { first: string, second: string, ...T, third: string } =
+              ~~~~~~~~~~~~~~~~~~~~
+!!! error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; second: string; ...T; third: string; }'.
+            { first: '1', ...t, second: '2', ...u, third: '3' }; // error, 'U' is missing
+        const interspersedOrder1: { first: string, ...T, second: string, ...U, third: string, secondsecond: string } =
+            { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // ok
+        const interspersedOrder2: { first: string, second: string, secondsecond: string, third: string, ...T, ...U } =
+            { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // ok
+    
+    
+        const mismatchFirst: { first: string, ...T, second: string, ...U, third: string } =
+              ~~~~~~~~~~~~~
+!!! error TS2322: Type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+!!! error TS2322:   Property 'first' is missing in type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }'.
+            { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, 'first' not found
+        const mismatchSecond: { first: string, ...T, second: string, ...U, third: string } =
+              ~~~~~~~~~~~~~~
+!!! error TS2322: Type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+!!! error TS2322:   Property 'second' is missing in type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }'.
+            { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, 'second' not found
+        const mismatchLast: { first: string, ...T, second: string, ...U, third: string } =
+              ~~~~~~~~~~~~
+!!! error TS2322: Type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+!!! error TS2322:   Property 'third' is missing in type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }'.
+            { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, 'third' not found
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadGeneric.js b/tests/baselines/reference/objectSpreadGeneric.js
new file mode 100644
index 0000000000000..593ab73f98fac
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadGeneric.js
@@ -0,0 +1,79 @@
+//// [objectSpreadGeneric.ts]
+function f<T, U, V>(t: T, u: U, v: V): void {
+    let o: { ...T, ...U, ...V };
+    const same: { ...T, ...U, ...V } = o; // ok
+    const reversed: { ...V, ...U, ...T } = o; // error, reversed
+    const reversed2: { ...U, ...T, ...V } = o; // error, U and T are still reversed
+    const missingT: { ...U, ...V } = o; // error, missing T
+    const missingU: { ...T, ...V } = o; // error, missing U
+    const missingV: { ...T, ...U } = o; // error, missing V
+    const atEnd: { ...T, ...U, second: string } = { ...t, ...u, second: 'foo' }; // ok
+    const atBeginning: { first: string, ...T, ...U, } = { first: 'foo', ...t, ...u }; // ok
+
+    const emptyTarget: { } = { ...t, ...u } // ok
+    const emptySource: { ...T, ...U } = { }; // error, {} is not assignable to U (or T)
+
+    let optionalNumber: { sn?: number };
+    let optionalString: { sn?: string };
+    let optionalBoolean: { sn?: boolean };
+    const unionCutoff: { ...T, sn?: number | string | boolean } =
+        { ...optionalBoolean, ...t, ...optionalString, ...optionalNumber } // ok
+    unionCutoff.sn; // ok
+    const optionalCutoff = { ...t, ...optionalNumber }; // ok
+    optionalCutoff.sn; // ok
+
+    const interspersed: { first: string, ...T, second: string, ...U, third: string } =
+        { first: '1', ...t, second: '2', ...u, third: '3' }; // ok
+    const interspersedMissingU: { first: string, second: string, ...T, third: string } =
+        { first: '1', ...t, second: '2', ...u, third: '3' }; // error, 'U' is missing
+    const interspersedOrder1: { first: string, ...T, second: string, ...U, third: string, secondsecond: string } =
+        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // ok
+    const interspersedOrder2: { first: string, second: string, secondsecond: string, third: string, ...T, ...U } =
+        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // ok
+
+
+    const mismatchFirst: { first: string, ...T, second: string, ...U, third: string } =
+        { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, 'first' not found
+    const mismatchSecond: { first: string, ...T, second: string, ...U, third: string } =
+        { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, 'second' not found
+    const mismatchLast: { first: string, ...T, second: string, ...U, third: string } =
+        { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, 'third' not found
+}
+
+
+//// [objectSpreadGeneric.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+function f(t, u, v) {
+    var o;
+    var same = o; // ok
+    var reversed = o; // error, reversed
+    var reversed2 = o; // error, U and T are still reversed
+    var missingT = o; // error, missing T
+    var missingU = o; // error, missing U
+    var missingV = o; // error, missing V
+    var atEnd = __assign({}, t, u, { second: 'foo' }); // ok
+    var atBeginning = __assign({ first: 'foo' }, t, u); // ok
+    var emptyTarget = __assign({}, t, u); // ok
+    var emptySource = {}; // error, {} is not assignable to U (or T)
+    var optionalNumber;
+    var optionalString;
+    var optionalBoolean;
+    var unionCutoff = __assign({}, optionalBoolean, t, optionalString, optionalNumber); // ok
+    unionCutoff.sn; // ok
+    var optionalCutoff = __assign({}, t, optionalNumber); // ok
+    optionalCutoff.sn; // ok
+    var interspersed = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3' }); // ok
+    var interspersedMissingU = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3' }); // error, 'U' is missing
+    var interspersedOrder1 = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3', secondsecond: 'false' }); // ok
+    var interspersedOrder2 = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3', secondsecond: 'false' }); // ok
+    var mismatchFirst = __assign({ firrrrrrst: '1' }, t, { second: '2' }, u, { third: '3' }); // error, 'first' not found
+    var mismatchSecond = __assign({ first: '1' }, t, { ssssssssecond: '2' }, u, { third: '3' }); // error, 'second' not found
+    var mismatchLast = __assign({ first: '1' }, t, { second: '2' }, u, { thirrrrrrrd: '3' }); // error, 'third' not found
+}
diff --git a/tests/baselines/reference/objectSpreadNegative.errors.txt b/tests/baselines/reference/objectSpreadNegative.errors.txt
new file mode 100644
index 0000000000000..1ee3acb823c6a
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadNegative.errors.txt
@@ -0,0 +1,93 @@
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(13,30): error TS2339: Property 'x' does not exist on type '{ ...PublicX; ...PrivateOptionalX }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(16,5): error TS2322: Type '{ ...{ sn?: string; }; ...{ sn?: number; } }' is not assignable to type '{ sn: string | number; }'.
+  Property 'sn' is optional in type '{ ...{ sn?: string; }; ...{ sn?: number; } }' but required in type '{ sn: string | number; }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(22,5): error TS2322: Type '{ s: string; }' is not assignable to type '{ ...Bool; ...Str }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(24,1): error TS2322: Type 'Bool' is not assignable to type '{ ...Bool; ...Str }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(27,15): error TS2697: Spread properties must be identifiers, property accesses, or object literals.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(28,15): error TS2697: Spread properties must be identifiers, property accesses, or object literals.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(31,36): error TS2300: Duplicate identifier 'b'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(31,53): error TS2300: Duplicate identifier 'b'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(36,12): error TS2339: Property 'b' does not exist on type '{ ...{ b: number; } }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(42,9): error TS2339: Property 'm' does not exist on type '{ ...C }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(45,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ ...PublicX }' has no compatible call signatures.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(46,1): error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(48,39): error TS2697: Spread properties must be identifiers, property accesses, or object literals.
+
+
+==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (13 errors) ====
+    let o = { a: 1, b: 'no' }
+    
+    /// private propagates
+    class PrivateOptionalX {
+        private x?: number;
+    }
+    class PublicX {
+        public x: number;
+    }
+    let privateOptionalx: PrivateOptionalX;
+    let publicx: PublicX;
+    let o3 = { ...publicx, ...privateOptionalx };
+    let sn: string | number = o3.x; // error, x is private
+                                 ~
+!!! error TS2339: Property 'x' does not exist on type '{ ...PublicX; ...PrivateOptionalX }'.
+    let optionalString: { sn?: string };
+    let optionalNumber: { sn?: number };
+    let allOptional: { sn: string | number } = { ...optionalString, ...optionalNumber };
+        ~~~~~~~~~~~
+!!! error TS2322: Type '{ ...{ sn?: string; }; ...{ sn?: number; } }' is not assignable to type '{ sn: string | number; }'.
+!!! error TS2322:   Property 'sn' is optional in type '{ ...{ sn?: string; }; ...{ sn?: number; } }' but required in type '{ sn: string | number; }'.
+    // error, 'sn' is optional in source, required in target
+    
+    // assignability as target
+    interface Bool { b: boolean };
+    interface Str { s: string };
+    let spread: { ...Bool, ...Str } = { s: 'foo' }; // error, missing 'b'
+        ~~~~~~
+!!! error TS2322: Type '{ s: string; }' is not assignable to type '{ ...Bool; ...Str }'.
+    let b: Bool;
+    spread = b; // error, missing 's'
+    ~~~~~~
+!!! error TS2322: Type 'Bool' is not assignable to type '{ ...Bool; ...Str }'.
+    
+    // expressions are not allowed
+    let o1 = { ...1 + 1 };
+                  ~~~~~
+!!! error TS2697: Spread properties must be identifiers, property accesses, or object literals.
+    let o2 = { ...(1 + 1) };
+                  ~~~~~~~
+!!! error TS2697: Spread properties must be identifiers, property accesses, or object literals.
+    
+    // literal repeats are not allowed, but spread repeats are fine
+    let duplicated = { b: 'bad', ...o, b: 'bad', ...o2, b: 'bad' }
+                                       ~
+!!! error TS2300: Duplicate identifier 'b'.
+                                                        ~
+!!! error TS2300: Duplicate identifier 'b'.
+    let duplicatedSpread = { ...o, ...o }
+    
+    // write-only properties get skipped
+    let setterOnly = { ...{ set b (bad: number) { } } };
+    setterOnly.b = 12; // error, 'b' does not exist
+               ~
+!!! error TS2339: Property 'b' does not exist on type '{ ...{ b: number; } }'.
+    
+    // methods are skipped because they aren't enumerable
+    class C { p = 1; m() { } }
+    let c: C = new C()
+    let spreadC = { ...c }
+    spreadC.m(); // error 'm' is not in '{ ... c }'
+            ~
+!!! error TS2339: Property 'm' does not exist on type '{ ...C }'.
+    
+    let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: number) };
+    callableConstructableSpread(12); // error, no call signature
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ ...PublicX }' has no compatible call signatures.
+    new callableConstructableSpread(12); // error, no construct signature
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
+    
+    let callableSpread = { ...publicx, ...(n => n + 1) }; // error, can't spread functions
+                                          ~~~~~~~~~~~~
+!!! error TS2697: Spread properties must be identifiers, property accesses, or object literals.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadNegative.js b/tests/baselines/reference/objectSpreadNegative.js
new file mode 100644
index 0000000000000..685760f944467
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadNegative.js
@@ -0,0 +1,108 @@
+//// [objectSpreadNegative.ts]
+let o = { a: 1, b: 'no' }
+
+/// private propagates
+class PrivateOptionalX {
+    private x?: number;
+}
+class PublicX {
+    public x: number;
+}
+let privateOptionalx: PrivateOptionalX;
+let publicx: PublicX;
+let o3 = { ...publicx, ...privateOptionalx };
+let sn: string | number = o3.x; // error, x is private
+let optionalString: { sn?: string };
+let optionalNumber: { sn?: number };
+let allOptional: { sn: string | number } = { ...optionalString, ...optionalNumber };
+// error, 'sn' is optional in source, required in target
+
+// assignability as target
+interface Bool { b: boolean };
+interface Str { s: string };
+let spread: { ...Bool, ...Str } = { s: 'foo' }; // error, missing 'b'
+let b: Bool;
+spread = b; // error, missing 's'
+
+// expressions are not allowed
+let o1 = { ...1 + 1 };
+let o2 = { ...(1 + 1) };
+
+// literal repeats are not allowed, but spread repeats are fine
+let duplicated = { b: 'bad', ...o, b: 'bad', ...o2, b: 'bad' }
+let duplicatedSpread = { ...o, ...o }
+
+// write-only properties get skipped
+let setterOnly = { ...{ set b (bad: number) { } } };
+setterOnly.b = 12; // error, 'b' does not exist
+
+// methods are skipped because they aren't enumerable
+class C { p = 1; m() { } }
+let c: C = new C()
+let spreadC = { ...c }
+spreadC.m(); // error 'm' is not in '{ ... c }'
+
+let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: number) };
+callableConstructableSpread(12); // error, no call signature
+new callableConstructableSpread(12); // error, no construct signature
+
+let callableSpread = { ...publicx, ...(n => n + 1) }; // error, can't spread functions
+
+
+//// [objectSpreadNegative.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+var o = { a: 1, b: 'no' };
+/// private propagates
+var PrivateOptionalX = (function () {
+    function PrivateOptionalX() {
+    }
+    return PrivateOptionalX;
+}());
+var PublicX = (function () {
+    function PublicX() {
+    }
+    return PublicX;
+}());
+var privateOptionalx;
+var publicx;
+var o3 = __assign({}, publicx, privateOptionalx);
+var sn = o3.x; // error, x is private
+var optionalString;
+var optionalNumber;
+var allOptional = __assign({}, optionalString, optionalNumber);
+;
+;
+var spread = { s: 'foo' }; // error, missing 'b'
+var b;
+spread = b; // error, missing 's'
+// expressions are not allowed
+var o1 = __assign({}, 1 + 1);
+var o2 = __assign({}, (1 + 1));
+// literal repeats are not allowed, but spread repeats are fine
+var duplicated = __assign({ b: 'bad' }, o, { b: 'bad' }, o2, { b: 'bad' });
+var duplicatedSpread = __assign({}, o, o);
+// write-only properties get skipped
+var setterOnly = __assign({ set b(bad: number) { } });
+setterOnly.b = 12; // error, 'b' does not exist
+// methods are skipped because they aren't enumerable
+var C = (function () {
+    function C() {
+        this.p = 1;
+    }
+    C.prototype.m = function () { };
+    return C;
+}());
+var c = new C();
+var spreadC = __assign({}, c);
+spreadC.m(); // error 'm' is not in '{ ... c }'
+var callableConstructableSpread;
+callableConstructableSpread(12); // error, no call signature
+new callableConstructableSpread(12); // error, no construct signature
+var callableSpread = __assign({}, publicx, (function (n) { return n + 1; })); // error, can't spread functions
diff --git a/tests/baselines/reference/objectSpreadNegativeParse.errors.txt b/tests/baselines/reference/objectSpreadNegativeParse.errors.txt
new file mode 100644
index 0000000000000..41651fb1d1c8e
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadNegativeParse.errors.txt
@@ -0,0 +1,35 @@
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(1,15): error TS2304: Cannot find name 'o'.
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(1,18): error TS1109: Expression expected.
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(2,15): error TS1109: Expression expected.
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(2,16): error TS2304: Cannot find name 'o'.
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(3,15): error TS2304: Cannot find name 'matchMedia'.
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(3,28): error TS1005: ',' expected.
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(3,31): error TS1128: Declaration or statement expected.
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(4,16): error TS2304: Cannot find name 'get'.
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(4,20): error TS1005: ',' expected.
+
+
+==== tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts (9 errors) ====
+    let o7 = { ...o? };
+                  ~
+!!! error TS2304: Cannot find name 'o'.
+                     ~
+!!! error TS1109: Expression expected.
+    let o8 = { ...*o };
+                  ~
+!!! error TS1109: Expression expected.
+                   ~
+!!! error TS2304: Cannot find name 'o'.
+    let o9 = { ...matchMedia() { }};
+                  ~~~~~~~~~~
+!!! error TS2304: Cannot find name 'matchMedia'.
+                               ~
+!!! error TS1005: ',' expected.
+                                  ~
+!!! error TS1128: Declaration or statement expected.
+    let o10 = { ...get x() { return 12; }};
+                   ~~~
+!!! error TS2304: Cannot find name 'get'.
+                       ~
+!!! error TS1005: ',' expected.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadNegativeParse.js b/tests/baselines/reference/objectSpreadNegativeParse.js
new file mode 100644
index 0000000000000..297c56c3e62ae
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadNegativeParse.js
@@ -0,0 +1,21 @@
+//// [objectSpreadNegativeParse.ts]
+let o7 = { ...o? };
+let o8 = { ...*o };
+let o9 = { ...matchMedia() { }};
+let o10 = { ...get x() { return 12; }};
+
+
+//// [objectSpreadNegativeParse.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+var o7 = __assign({}, o ?  : );
+var o8 = __assign({},  * o);
+var o9 = __assign({}, matchMedia()), _a = void 0;
+;
+var o10 = __assign({}, get, { x: function () { return 12; } });

From 39385590b6b9571d85ab74b43faaf7caddd9c388 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 26 Sep 2016 09:43:59 -0700
Subject: [PATCH 006/224] Move interfaceSpread to correct location

---
 tests/baselines/reference/interfaceSpread.errors.txt      | 8 ++++----
 .../destructuring => types/spread}/interfaceSpread.ts     | 0
 2 files changed, 4 insertions(+), 4 deletions(-)
 rename tests/cases/conformance/{es6/destructuring => types/spread}/interfaceSpread.ts (100%)

diff --git a/tests/baselines/reference/interfaceSpread.errors.txt b/tests/baselines/reference/interfaceSpread.errors.txt
index 27aab11491c5a..2b27c972cc895 100644
--- a/tests/baselines/reference/interfaceSpread.errors.txt
+++ b/tests/baselines/reference/interfaceSpread.errors.txt
@@ -1,9 +1,9 @@
-tests/cases/conformance/es6/destructuring/interfaceSpread.ts(2,5): error TS2699: Interface declaration cannot contain a spread property.
-tests/cases/conformance/es6/destructuring/interfaceSpread.ts(7,10): error TS2339: Property 'jam' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
-tests/cases/conformance/es6/destructuring/interfaceSpread.ts(8,10): error TS2339: Property 'peanutButter' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
+tests/cases/conformance/types/spread/interfaceSpread.ts(2,5): error TS2699: Interface declaration cannot contain a spread property.
+tests/cases/conformance/types/spread/interfaceSpread.ts(7,10): error TS2339: Property 'jam' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
+tests/cases/conformance/types/spread/interfaceSpread.ts(8,10): error TS2339: Property 'peanutButter' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
 
 
-==== tests/cases/conformance/es6/destructuring/interfaceSpread.ts (3 errors) ====
+==== tests/cases/conformance/types/spread/interfaceSpread.ts (3 errors) ====
     interface Congealed<T, U> {
         ...T
         ~~~~
diff --git a/tests/cases/conformance/es6/destructuring/interfaceSpread.ts b/tests/cases/conformance/types/spread/interfaceSpread.ts
similarity index 100%
rename from tests/cases/conformance/es6/destructuring/interfaceSpread.ts
rename to tests/cases/conformance/types/spread/interfaceSpread.ts

From 63f8c991733ec3f4ba5819452281f91e2206b8ed Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 26 Sep 2016 10:24:05 -0700
Subject: [PATCH 007/224] Object.assign uses spread types now

---
 src/lib/es2015.core.d.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/lib/es2015.core.d.ts b/src/lib/es2015.core.d.ts
index 5d570bb086630..2373b828fdd6d 100644
--- a/src/lib/es2015.core.d.ts
+++ b/src/lib/es2015.core.d.ts
@@ -278,7 +278,7 @@ interface ObjectConstructor {
       * @param target The target object to copy to.
       * @param source The source object from which to copy properties.
       */
-    assign<T, U>(target: T, source: U): T & U;
+    assign<T, U>(target: T, source: U): { ...T, ...U };
 
     /**
       * Copy the values of all of the enumerable own properties from one or more source objects to a
@@ -287,7 +287,7 @@ interface ObjectConstructor {
       * @param source1 The first source object from which to copy properties.
       * @param source2 The second source object from which to copy properties.
       */
-    assign<T, U, V>(target: T, source1: U, source2: V): T & U & V;
+    assign<T, U, V>(target: T, source1: U, source2: V): { ...T, ...U, ...V };
 
     /**
       * Copy the values of all of the enumerable own properties from one or more source objects to a
@@ -297,7 +297,7 @@ interface ObjectConstructor {
       * @param source2 The second source object from which to copy properties.
       * @param source3 The third source object from which to copy properties.
       */
-    assign<T, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W;
+    assign<T, U, V, W>(target: T, source1: U, source2: V, source3: W): { ...T, ...U, ...V, ...W };
 
     /**
       * Copy the values of all of the enumerable own properties from one or more source objects to a

From a0db19749ab5316254fdfa7d3dfdaa49aee3ed7a Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 26 Sep 2016 11:50:02 -0700
Subject: [PATCH 008/224] Rename Spread[Element]Expression

1. SpreadElementExpression (existing, for arrays) -> SpreadExpression
2. SpreadElement (new for object literals) -> SpreadElementExpression
---
 src/compiler/binder.ts                     | 23 +++++++------
 src/compiler/checker.ts                    | 38 +++++++++++-----------
 src/compiler/emitter.ts                    |  6 ++--
 src/compiler/factory.ts                    |  6 ++--
 src/compiler/parser.ts                     | 20 +++++-------
 src/compiler/transformers/destructuring.ts |  4 +--
 src/compiler/transformers/es6.ts           | 36 ++++++++++----------
 src/compiler/transformers/experimental.ts  |  4 +--
 src/compiler/transformers/module/system.ts |  6 ++--
 src/compiler/types.ts                      | 18 +++++-----
 src/compiler/utilities.ts                  | 14 ++++----
 src/compiler/visitor.ts                    | 12 +++----
 src/services/breakpoints.ts                |  2 +-
 src/services/utilities.ts                  |  4 +--
 14 files changed, 96 insertions(+), 97 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index d3217fd70a850..c198b5c01ff59 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -1063,8 +1063,8 @@ namespace ts {
             }
             else if (node.kind === SyntaxKind.ArrayLiteralExpression) {
                 for (const e of (<ArrayLiteralExpression>node).elements) {
-                    if (e.kind === SyntaxKind.SpreadElementExpression) {
-                        bindAssignmentTargetFlow((<SpreadElementExpression>e).expression);
+                    if (e.kind === SyntaxKind.SpreadExpression) {
+                        bindAssignmentTargetFlow((<SpreadExpression>e).expression);
                     }
                     else {
                         bindDestructuringTargetFlow(e);
@@ -1079,6 +1079,9 @@ namespace ts {
                     else if (p.kind === SyntaxKind.ShorthandPropertyAssignment) {
                         bindAssignmentTargetFlow((<ShorthandPropertyAssignment>p).name);
                     }
+                    else if (p.kind === SyntaxKind.SpreadElementExpression) {
+                        bindAssignmentTargetFlow((<SpreadElementExpression>p).expression);
+                    }
                 }
             }
         }
@@ -1825,7 +1828,7 @@ namespace ts {
                 case SyntaxKind.EnumMember:
                     return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.EnumMember, SymbolFlags.EnumMemberExcludes);
 
-                case SyntaxKind.SpreadElement:
+                case SyntaxKind.SpreadElementExpression:
                 case SyntaxKind.JsxSpreadAttribute:
                     emitFlags |= NodeFlags.HasSpreadAttribute;
                     return;
@@ -2369,9 +2372,9 @@ namespace ts {
         const expression = node.expression;
         const expressionKind = expression.kind;
 
-        if (subtreeFlags & TransformFlags.ContainsSpreadElementExpression
+        if (subtreeFlags & TransformFlags.ContainsSpreadExpression
             || isSuperOrSuperProperty(expression, expressionKind)) {
-            // If the this node contains a SpreadElementExpression, or is a super call, then it is an ES6
+            // If the this node contains a SpreadExpression, or is a super call, then it is an ES6
             // node.
             transformFlags |= TransformFlags.AssertES6;
         }
@@ -2957,10 +2960,10 @@ namespace ts {
                 }
                 break;
 
-            case SyntaxKind.SpreadElement:
+            case SyntaxKind.SpreadExpression:
             case SyntaxKind.SpreadElementExpression:
                 // This node is ES6 or ES future syntax, but is handled by a containing node.
-                transformFlags |= TransformFlags.ContainsSpreadElementExpression;
+                transformFlags |= TransformFlags.ContainsSpreadExpression;
                 break;
 
             case SyntaxKind.SuperKeyword:
@@ -2998,7 +3001,7 @@ namespace ts {
                     transformFlags |= TransformFlags.ContainsLexicalThis;
                 }
 
-                if (subtreeFlags & TransformFlags.ContainsSpreadElementExpression) {
+                if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
                     // If an ObjectLiteralExpression contains a spread element, then it
                     // is an ES experimental node.
                     transformFlags |= TransformFlags.AssertExperimental;
@@ -3009,8 +3012,8 @@ namespace ts {
             case SyntaxKind.ArrayLiteralExpression:
             case SyntaxKind.NewExpression:
                 excludeFlags = TransformFlags.ArrayLiteralOrCallOrNewExcludes;
-                if (subtreeFlags & TransformFlags.ContainsSpreadElementExpression) {
-                    // If the this node contains a SpreadElementExpression, then it is an ES6
+                if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+                    // If the this node contains a SpreadExpression, then it is an ES6
                     // node.
                     transformFlags |= TransformFlags.AssertES6;
                 }
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 3578aeb5e4bb9..1f31d58b19709 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -8379,7 +8379,7 @@ namespace ts {
                 unknownType;
         }
 
-        function getTypeOfDestructuredSpreadElement(type: Type) {
+        function getTypeOfDestructuredSpreadExpression(type: Type) {
             return createArrayType(checkIteratedTypeOrElementType(type, /*errorNode*/ undefined, /*allowStringInput*/ false) || unknownType);
         }
 
@@ -8393,8 +8393,8 @@ namespace ts {
             return getTypeOfDestructuredArrayElement(getAssignedType(node), indexOf(node.elements, element));
         }
 
-        function getAssignedTypeOfSpreadElement(node: SpreadElementExpression): Type {
-            return getTypeOfDestructuredSpreadElement(getAssignedType(<ArrayLiteralExpression>node.parent));
+        function getAssignedTypeOfSpreadExpression(node: SpreadExpression): Type {
+            return getTypeOfDestructuredSpreadExpression(getAssignedType(<ArrayLiteralExpression>node.parent));
         }
 
         function getAssignedTypeOfPropertyAssignment(node: PropertyAssignment | ShorthandPropertyAssignment): Type {
@@ -8418,8 +8418,8 @@ namespace ts {
                     return undefinedType;
                 case SyntaxKind.ArrayLiteralExpression:
                     return getAssignedTypeOfArrayLiteralElement(<ArrayLiteralExpression>parent, node);
-                case SyntaxKind.SpreadElementExpression:
-                    return getAssignedTypeOfSpreadElement(<SpreadElementExpression>parent);
+                case SyntaxKind.SpreadExpression:
+                    return getAssignedTypeOfSpreadExpression(<SpreadExpression>parent);
                 case SyntaxKind.PropertyAssignment:
                     return getAssignedTypeOfPropertyAssignment(<PropertyAssignment>parent);
                 case SyntaxKind.ShorthandPropertyAssignment:
@@ -8435,7 +8435,7 @@ namespace ts {
                 getTypeOfDestructuredProperty(parentType, node.propertyName || <Identifier>node.name) :
                 !node.dotDotDotToken ?
                     getTypeOfDestructuredArrayElement(parentType, indexOf(pattern.elements, node)) :
-                    getTypeOfDestructuredSpreadElement(parentType);
+                    getTypeOfDestructuredSpreadExpression(parentType);
             return getTypeWithDefault(type, node.initializer);
         }
 
@@ -10221,7 +10221,7 @@ namespace ts {
             return mapper && mapper.context;
         }
 
-        function checkSpreadElementExpression(node: SpreadElementExpression, contextualMapper?: TypeMapper): Type {
+        function checkSpreadExpression(node: SpreadExpression, contextualMapper?: TypeMapper): Type {
             // It is usually not safe to call checkExpressionCached if we can be contextually typing.
             // You can tell that we are contextually typing because of the contextualMapper parameter.
             // While it is true that a spread element can have a contextual type, it does not do anything
@@ -10243,7 +10243,7 @@ namespace ts {
             const elementTypes: Type[] = [];
             const inDestructuringPattern = isAssignmentTarget(node);
             for (const e of elements) {
-                if (inDestructuringPattern && e.kind === SyntaxKind.SpreadElementExpression) {
+                if (inDestructuringPattern && e.kind === SyntaxKind.SpreadExpression) {
                     // Given the following situation:
                     //    var c: {};
                     //    [...c] = ["", 0];
@@ -10256,7 +10256,7 @@ namespace ts {
                     // get the contextual element type from it. So we do something similar to
                     // getContextualTypeForElementExpression, which will crucially not error
                     // if there is no index type / iterated type.
-                    const restArrayType = checkExpression((<SpreadElementExpression>e).expression, contextualMapper);
+                    const restArrayType = checkExpression((<SpreadExpression>e).expression, contextualMapper);
                     const restElementType = getIndexTypeOfType(restArrayType, IndexKind.Number) ||
                         (languageVersion >= ScriptTarget.ES6 ? getElementTypeOfIterable(restArrayType, /*errorNode*/ undefined) : undefined);
                     if (restElementType) {
@@ -10267,7 +10267,7 @@ namespace ts {
                     const type = checkExpressionForMutableLocation(e, contextualMapper);
                     elementTypes.push(type);
                 }
-                hasSpreadElement = hasSpreadElement || e.kind === SyntaxKind.SpreadElementExpression;
+                hasSpreadElement = hasSpreadElement || e.kind === SyntaxKind.SpreadExpression;
             }
             if (!hasSpreadElement) {
                 // If array literal is actually a destructuring pattern, mark it as an implied type. We do this such
@@ -10456,7 +10456,7 @@ namespace ts {
                     prop.target = member;
                     member = prop;
                 }
-                else if (memberDecl.kind === SyntaxKind.SpreadElement) {
+                else if (memberDecl.kind === SyntaxKind.SpreadElementExpression) {
                     if (propertiesArray.length > 0) {
                         const t = createObjectLiteralType(node, hasComputedStringProperty, hasComputedNumberProperty, propertiesArray, propertiesTable, typeFlags, patternWithComputedProperties, inDestructuringPattern) as SpreadElementType;
                         t.isDeclaredProperty = true;
@@ -10466,7 +10466,7 @@ namespace ts {
                         hasComputedStringProperty = false;
                         hasComputedNumberProperty = false;
                     }
-                    spreads.push(checkExpression((memberDecl as SpreadElement).target) as SpreadElementType);
+                    spreads.push(checkExpression((memberDecl as SpreadElementExpression).expression) as SpreadElementType);
                     continue;
                 }
                 else {
@@ -11503,7 +11503,7 @@ namespace ts {
         function getSpreadArgumentIndex(args: Expression[]): number {
             for (let i = 0; i < args.length; i++) {
                 const arg = args[i];
-                if (arg && arg.kind === SyntaxKind.SpreadElementExpression) {
+                if (arg && arg.kind === SyntaxKind.SpreadExpression) {
                     return i;
                 }
             }
@@ -13474,7 +13474,7 @@ namespace ts {
             const elements = node.elements;
             const element = elements[elementIndex];
             if (element.kind !== SyntaxKind.OmittedExpression) {
-                if (element.kind !== SyntaxKind.SpreadElementExpression) {
+                if (element.kind !== SyntaxKind.SpreadExpression) {
                     const propName = "" + elementIndex;
                     const type = isTypeAny(sourceType)
                         ? sourceType
@@ -13501,7 +13501,7 @@ namespace ts {
                         error(element, Diagnostics.A_rest_element_must_be_last_in_an_array_destructuring_pattern);
                     }
                     else {
-                        const restExpression = (<SpreadElementExpression>element).expression;
+                        const restExpression = (<SpreadExpression>element).expression;
                         if (restExpression.kind === SyntaxKind.BinaryExpression && (<BinaryExpression>restExpression).operatorToken.kind === SyntaxKind.EqualsToken) {
                             error((<BinaryExpression>restExpression).operatorToken, Diagnostics.A_rest_element_cannot_have_an_initializer);
                         }
@@ -14137,8 +14137,8 @@ namespace ts {
                     return checkBinaryExpression(<BinaryExpression>node, contextualMapper);
                 case SyntaxKind.ConditionalExpression:
                     return checkConditionalExpression(<ConditionalExpression>node, contextualMapper);
-                case SyntaxKind.SpreadElementExpression:
-                    return checkSpreadElementExpression(<SpreadElementExpression>node, contextualMapper);
+                case SyntaxKind.SpreadExpression:
+                    return checkSpreadExpression(<SpreadExpression>node, contextualMapper);
                 case SyntaxKind.OmittedExpression:
                     return undefinedWideningType;
                 case SyntaxKind.YieldExpression:
@@ -20048,8 +20048,8 @@ namespace ts {
             const GetOrSetAccessor = GetAccessor | SetAccessor;
 
             for (const prop of node.properties) {
-                if (prop.kind === SyntaxKind.SpreadElement) {
-                    const target = (prop as SpreadElement).target;
+                if (prop.kind === SyntaxKind.SpreadElementExpression) {
+                    const target = (prop as SpreadElementExpression).expression;
                     switch (target.kind) {
                         case SyntaxKind.Identifier:
                         case SyntaxKind.PropertyAccessExpression:
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index cd00f7ad76905..cc574414beb63 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -824,8 +824,8 @@ const _super = (function (geti, seti) {
                     return emitTemplateExpression(<TemplateExpression>node);
                 case SyntaxKind.YieldExpression:
                     return emitYieldExpression(<YieldExpression>node);
-                case SyntaxKind.SpreadElementExpression:
-                    return emitSpreadElementExpression(<SpreadElementExpression>node);
+                case SyntaxKind.SpreadExpression:
+                    return emitSpreadExpression(<SpreadExpression>node);
                 case SyntaxKind.ClassExpression:
                     return emitClassExpression(<ClassExpression>node);
                 case SyntaxKind.OmittedExpression:
@@ -1365,7 +1365,7 @@ const _super = (function (geti, seti) {
             emitExpressionWithPrefix(" ", node.expression);
         }
 
-        function emitSpreadElementExpression(node: SpreadElementExpression) {
+        function emitSpreadExpression(node: SpreadExpression) {
             write("...");
             emitExpression(node.expression);
         }
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 16eeb86f59a73..a8ee15c12c409 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -704,12 +704,12 @@ namespace ts {
     }
 
     export function createSpread(expression: Expression, location?: TextRange) {
-        const node = <SpreadElementExpression>createNode(SyntaxKind.SpreadElementExpression, location);
+        const node = <SpreadExpression>createNode(SyntaxKind.SpreadExpression, location);
         node.expression = parenthesizeExpressionForList(expression);
         return node;
     }
 
-    export function updateSpread(node: SpreadElementExpression, expression: Expression) {
+    export function updateSpread(node: SpreadExpression, expression: Expression) {
         if (node.expression !== expression) {
             return updateNode(createSpread(expression, node), node);
         }
@@ -2745,4 +2745,4 @@ namespace ts {
     function tryGetModuleNameFromDeclaration(declaration: ImportEqualsDeclaration | ImportDeclaration | ExportDeclaration, host: EmitHost, resolver: EmitResolver, compilerOptions: CompilerOptions) {
         return tryGetModuleNameFromFile(resolver.getExternalModuleFileFromDeclaration(declaration), host, compilerOptions);
     }
-}
\ No newline at end of file
+}
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index ae88b6d948b5b..e0d8790d14ccc 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -74,9 +74,8 @@ namespace ts {
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).questionToken) ||
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).equalsToken) ||
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).objectAssignmentInitializer);
-            case SyntaxKind.SpreadElement:
-                return visitNode(cbNode, (<SpreadElement>node).dotDotDotToken) ||
-                    visitNode(cbNode, (<SpreadElement>node).target);
+            case SyntaxKind.SpreadElementExpression:
+                return visitNode(cbNode, (<SpreadElementExpression>node).expression);
             case SyntaxKind.SpreadTypeElement:
                 return visitNode(cbNode, (node as SpreadTypeElement).type);
             case SyntaxKind.Parameter:
@@ -198,8 +197,8 @@ namespace ts {
                     visitNode(cbNode, (<ConditionalExpression>node).whenTrue) ||
                     visitNode(cbNode, (<ConditionalExpression>node).colonToken) ||
                     visitNode(cbNode, (<ConditionalExpression>node).whenFalse);
-            case SyntaxKind.SpreadElementExpression:
-                return visitNode(cbNode, (<SpreadElementExpression>node).expression);
+            case SyntaxKind.SpreadExpression:
+                return visitNode(cbNode, (<SpreadExpression>node).expression);
             case SyntaxKind.Block:
             case SyntaxKind.ModuleBlock:
                 return visitNodes(cbNodes, (<Block>node).statements);
@@ -4102,15 +4101,15 @@ namespace ts {
             return finishNode(node);
         }
 
-        function parseSpreadElement(): Expression {
-            const node = <SpreadElementExpression>createNode(SyntaxKind.SpreadElementExpression);
+        function parseSpreadExpression(): Expression {
+            const node = <SpreadExpression>createNode(SyntaxKind.SpreadExpression);
             parseExpected(SyntaxKind.DotDotDotToken);
             node.expression = parseAssignmentExpressionOrHigher();
             return finishNode(node);
         }
 
         function parseArgumentOrArrayLiteralElement(): Expression {
-            return token() === SyntaxKind.DotDotDotToken ? parseSpreadElement() :
+            return token() === SyntaxKind.DotDotDotToken ? parseSpreadExpression() :
                 token() === SyntaxKind.CommaToken ? <Expression>createNode(SyntaxKind.OmittedExpression) :
                     parseAssignmentExpressionOrHigher();
         }
@@ -4145,9 +4144,8 @@ namespace ts {
             const fullStart = scanner.getStartPos();
             const dotDotDotToken = parseOptionalToken(SyntaxKind.DotDotDotToken);
             if (dotDotDotToken) {
-                const spreadElement = <SpreadElement>createNode(SyntaxKind.SpreadElement, fullStart);
-                spreadElement.dotDotDotToken = dotDotDotToken;
-                spreadElement.target = parseAssignmentExpressionOrHigher();
+                const spreadElement = <SpreadElementExpression>createNode(SyntaxKind.SpreadElementExpression, fullStart);
+                spreadElement.expression = parseAssignmentExpressionOrHigher();
                 return addJSDocComment(finishNode(spreadElement));
             }
             const decorators = parseDecorators();
diff --git a/src/compiler/transformers/destructuring.ts b/src/compiler/transformers/destructuring.ts
index a66f5e21d784d..7d74e58f204ae 100644
--- a/src/compiler/transformers/destructuring.ts
+++ b/src/compiler/transformers/destructuring.ts
@@ -310,11 +310,11 @@ namespace ts {
                 const e = elements[i];
                 if (e.kind !== SyntaxKind.OmittedExpression) {
                     // Assignment for target = value.propName should highligh whole property, hence use e as source map node
-                    if (e.kind !== SyntaxKind.SpreadElementExpression) {
+                    if (e.kind !== SyntaxKind.SpreadExpression) {
                         emitDestructuringAssignment(e, createElementAccess(value, createLiteral(i)), e);
                     }
                     else if (i === numElements - 1) {
-                        emitDestructuringAssignment((<SpreadElementExpression>e).expression, createArraySlice(value, i), e);
+                        emitDestructuringAssignment((<SpreadExpression>e).expression, createArraySlice(value, i), e);
                     }
                 }
             }
diff --git a/src/compiler/transformers/es6.ts b/src/compiler/transformers/es6.ts
index 114a3aea54684..7582b14e4aaf1 100644
--- a/src/compiler/transformers/es6.ts
+++ b/src/compiler/transformers/es6.ts
@@ -2556,7 +2556,7 @@ namespace ts {
             // because we contain a SpreadElementExpression.
 
             const { target, thisArg } = createCallBinding(node.expression, hoistVariableDeclaration);
-            if (node.transformFlags & TransformFlags.ContainsSpreadElementExpression) {
+            if (node.transformFlags & TransformFlags.ContainsSpreadExpression) {
                 // [source]
                 //      f(...a, b)
                 //      x.m(...a, b)
@@ -2604,7 +2604,7 @@ namespace ts {
          */
         function visitNewExpression(node: NewExpression): LeftHandSideExpression {
             // We are here because we contain a SpreadElementExpression.
-            Debug.assert((node.transformFlags & TransformFlags.ContainsSpreadElementExpression) !== 0);
+            Debug.assert((node.transformFlags & TransformFlags.ContainsSpreadExpression) !== 0);
 
             // [source]
             //      new C(...a)
@@ -2625,7 +2625,7 @@ namespace ts {
         }
 
         /**
-         * Transforms an array of Expression nodes that contains a SpreadElementExpression.
+         * Transforms an array of Expression nodes that contains a SpreadExpression.
          *
          * @param elements The array of Expression nodes.
          * @param needsUniqueCopy A value indicating whether to ensure that the result is a fresh array.
@@ -2642,14 +2642,14 @@ namespace ts {
             // expressions into an array literal.
             const numElements = elements.length;
             const segments = flatten(
-                spanMap(elements, partitionSpreadElement, (partition, visitPartition, start, end) =>
+                spanMap(elements, partitionSpread, (partition, visitPartition, start, end) =>
                     visitPartition(partition, multiLine, hasTrailingComma && end === numElements)
                 )
             );
 
             if (segments.length === 1) {
                 const firstElement = elements[0];
-                return needsUniqueCopy && isSpreadElementExpression(firstElement) && firstElement.expression.kind !== SyntaxKind.ArrayLiteralExpression
+                return needsUniqueCopy && isSpreadExpression(firstElement) && firstElement.expression.kind !== SyntaxKind.ArrayLiteralExpression
                     ? createArraySlice(segments[0])
                     : segments[0];
             }
@@ -2658,17 +2658,17 @@ namespace ts {
             return createArrayConcat(segments.shift(), segments);
         }
 
-        function partitionSpreadElement(node: Expression) {
-            return isSpreadElementExpression(node)
-                ? visitSpanOfSpreadElements
-                : visitSpanOfNonSpreadElements;
+        function partitionSpread(node: Expression) {
+            return isSpreadExpression(node)
+                ? visitSpanOfSpreads
+                : visitSpanOfNonSpreads;
         }
 
-        function visitSpanOfSpreadElements(chunk: Expression[], multiLine: boolean, hasTrailingComma: boolean): VisitResult<Expression> {
-            return map(chunk, visitExpressionOfSpreadElement);
+        function visitSpanOfSpreads(chunk: Expression[], multiLine: boolean, hasTrailingComma: boolean): VisitResult<Expression> {
+            return map(chunk, visitExpressionOfSpread);
         }
 
-        function visitSpanOfNonSpreadElements(chunk: Expression[], multiLine: boolean, hasTrailingComma: boolean): VisitResult<Expression> {
+        function visitSpanOfNonSpreads(chunk: Expression[], multiLine: boolean, hasTrailingComma: boolean): VisitResult<Expression> {
             return createArrayLiteral(
                 visitNodes(createNodeArray(chunk, /*location*/ undefined, hasTrailingComma), visitor, isExpression),
                 /*location*/ undefined,
@@ -2677,11 +2677,11 @@ namespace ts {
         }
 
         /**
-         * Transforms the expression of a SpreadElementExpression node.
+         * Transforms the expression of a SpreadExpression node.
          *
-         * @param node A SpreadElementExpression node.
+         * @param node A SpreadExpression node.
          */
-        function visitExpressionOfSpreadElement(node: SpreadElementExpression) {
+        function visitExpressionOfSpread(node: SpreadExpression) {
             return visitNode(node.expression, visitor, isExpression);
         }
 
@@ -3096,12 +3096,12 @@ namespace ts {
             }
 
             const callArgument = singleOrUndefined((<CallExpression>statementExpression).arguments);
-            if (!callArgument || !nodeIsSynthesized(callArgument) || callArgument.kind !== SyntaxKind.SpreadElementExpression) {
+            if (!callArgument || !nodeIsSynthesized(callArgument) || callArgument.kind !== SyntaxKind.SpreadExpression) {
                 return false;
             }
 
-            const expression = (<SpreadElementExpression>callArgument).expression;
+            const expression = (<SpreadExpression>callArgument).expression;
             return isIdentifier(expression) && expression === parameter.name;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/compiler/transformers/experimental.ts b/src/compiler/transformers/experimental.ts
index 715cf91afd3e6..85af37709c744 100644
--- a/src/compiler/transformers/experimental.ts
+++ b/src/compiler/transformers/experimental.ts
@@ -36,12 +36,12 @@ namespace ts {
             let chunkObject: (ShorthandPropertyAssignment | PropertyAssignment)[];
             const objects: Expression[] = [];
             for (const e of elements) {
-                if (e.kind === SyntaxKind.SpreadElement) {
+                if (e.kind === SyntaxKind.SpreadElementExpression) {
                     if (chunkObject) {
                         objects.push(createObjectLiteral(chunkObject));
                         chunkObject = undefined;
                     }
-                    const target = (e as SpreadElement).target;
+                    const target = (e as SpreadElementExpression).expression;
                     objects.push(visitNode(target, visitor, isExpression));
                 }
                 else {
diff --git a/src/compiler/transformers/module/system.ts b/src/compiler/transformers/module/system.ts
index 7b013e18e7dc0..de1522a015085 100644
--- a/src/compiler/transformers/module/system.ts
+++ b/src/compiler/transformers/module/system.ts
@@ -1120,7 +1120,7 @@ namespace ts {
         }
 
         function hasExportedReferenceInArrayDestructuringElement(node: Expression): boolean {
-            if (isSpreadElementExpression(node)) {
+            if (isSpreadExpression(node)) {
                 const expression = node.expression;
                 return isIdentifier(expression) && isExportedBinding(expression);
             }
@@ -1139,7 +1139,7 @@ namespace ts {
             else if (isIdentifier(node)) {
                 return isExportedBinding(node);
             }
-            else if (isSpreadElementExpression(node)) {
+            else if (isSpreadExpression(node)) {
                 const expression = node.expression;
                 return isIdentifier(expression) && isExportedBinding(expression);
             }
@@ -1400,4 +1400,4 @@ namespace ts {
             return updated;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index cdf42ebea4ffc..bfadea3179420 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -241,7 +241,7 @@ namespace ts {
         ConditionalExpression,
         TemplateExpression,
         YieldExpression,
-        SpreadElementExpression,
+        SpreadExpression,
         ClassExpression,
         OmittedExpression,
         ExpressionWithTypeArguments,
@@ -316,8 +316,8 @@ namespace ts {
         // Property assignments
         PropertyAssignment,
         ShorthandPropertyAssignment,
-        SpreadElement, // maybe name it SpreadProperty?
-        SpreadTypeElement, // maybe name it SpreadTypeNode?
+        SpreadElementExpression,
+        SpreadTypeElement,
 
 
         // Enum
@@ -674,9 +674,7 @@ namespace ts {
     }
 
     // @kind(SyntaxKind.SpreadElementExpression)
-    export interface SpreadElement extends ObjectLiteralElement {
-        dotDotDotToken: Node;
-        target: Expression;
+    export interface SpreadElementExpression extends ObjectLiteralElement, SpreadExpression {
     }
 
     // SyntaxKind.VariableDeclaration
@@ -1056,8 +1054,8 @@ namespace ts {
         multiLine?: boolean;
     }
 
-    // @kind(SyntaxKind.SpreadElementExpression)
-    export interface SpreadElementExpression extends Expression {
+    // @kind(SyntaxKind.SpreadExpression)
+    export interface SpreadExpression extends Expression {
         expression: Expression;
     }
 
@@ -3140,7 +3138,7 @@ namespace ts {
         ContainsLexicalThisInComputedPropertyName = 1 << 17,
         ContainsDefaultValueAssignments = 1 << 18,
         ContainsParameterPropertyAssignments = 1 << 19,
-        ContainsSpreadElementExpression = 1 << 20,
+        ContainsSpreadExpression = 1 << 20,
         ContainsComputedPropertyName = 1 << 21,
         ContainsBlockScopedBinding = 1 << 22,
         ContainsBindingPattern = 1 << 23,
@@ -3170,7 +3168,7 @@ namespace ts {
         ModuleExcludes = NodeExcludes | ContainsDecorators | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding | ContainsHoistedDeclarationOrCompletion,
         TypeExcludes = ~ContainsTypeScript,
         ObjectLiteralExcludes = NodeExcludes | ContainsDecorators | ContainsComputedPropertyName | ContainsLexicalThisInComputedPropertyName,
-        ArrayLiteralOrCallOrNewExcludes = NodeExcludes | ContainsSpreadElementExpression,
+        ArrayLiteralOrCallOrNewExcludes = NodeExcludes | ContainsSpreadExpression,
         VariableDeclarationListExcludes = NodeExcludes | ContainsBindingPattern,
         ParameterExcludes = NodeExcludes | ContainsBindingPattern,
 
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 67ea182bf9868..30a09ade0f596 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -1178,7 +1178,7 @@ namespace ts {
             case SyntaxKind.PostfixUnaryExpression:
             case SyntaxKind.BinaryExpression:
             case SyntaxKind.ConditionalExpression:
-            case SyntaxKind.SpreadElementExpression:
+            case SyntaxKind.SpreadExpression:
             case SyntaxKind.TemplateExpression:
             case SyntaxKind.NoSubstitutionTemplateLiteral:
             case SyntaxKind.OmittedExpression:
@@ -1633,7 +1633,7 @@ namespace ts {
         }
         while (true) {
             const parent = node.parent;
-            if (parent.kind === SyntaxKind.ArrayLiteralExpression || parent.kind === SyntaxKind.SpreadElementExpression) {
+            if (parent.kind === SyntaxKind.ArrayLiteralExpression || parent.kind === SyntaxKind.SpreadExpression) {
                 node = parent;
                 continue;
             }
@@ -2209,7 +2209,7 @@ namespace ts {
             case SyntaxKind.YieldExpression:
                 return 2;
 
-            case SyntaxKind.SpreadElementExpression:
+            case SyntaxKind.SpreadExpression:
                 return 1;
 
             default:
@@ -3740,7 +3740,7 @@ namespace ts {
         const kind = node.kind;
         return kind === SyntaxKind.PropertyAssignment
             || kind === SyntaxKind.ShorthandPropertyAssignment
-            || kind === SyntaxKind.SpreadElement
+            || kind === SyntaxKind.SpreadElementExpression
             || kind === SyntaxKind.MethodDeclaration
             || kind === SyntaxKind.GetAccessor
             || kind === SyntaxKind.SetAccessor
@@ -3820,8 +3820,8 @@ namespace ts {
             || kind === SyntaxKind.NoSubstitutionTemplateLiteral;
     }
 
-    export function isSpreadElementExpression(node: Node): node is SpreadElementExpression {
-        return node.kind === SyntaxKind.SpreadElementExpression;
+    export function isSpreadExpression(node: Node): node is SpreadExpression {
+        return node.kind === SyntaxKind.SpreadExpression;
     }
 
     export function isExpressionWithTypeArguments(node: Node): node is ExpressionWithTypeArguments {
@@ -3879,7 +3879,7 @@ namespace ts {
             || kind === SyntaxKind.YieldExpression
             || kind === SyntaxKind.ArrowFunction
             || kind === SyntaxKind.BinaryExpression
-            || kind === SyntaxKind.SpreadElementExpression
+            || kind === SyntaxKind.SpreadExpression
             || kind === SyntaxKind.AsExpression
             || kind === SyntaxKind.OmittedExpression
             || isUnaryExpressionKind(kind);
diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index 1e0cadaaa6b99..691e13b03d69c 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -267,9 +267,9 @@ namespace ts {
             case SyntaxKind.VoidExpression:
             case SyntaxKind.AwaitExpression:
             case SyntaxKind.YieldExpression:
-            case SyntaxKind.SpreadElementExpression:
+            case SyntaxKind.SpreadExpression:
             case SyntaxKind.NonNullExpression:
-                result = reduceNode((<ParenthesizedExpression | DeleteExpression | TypeOfExpression | VoidExpression | AwaitExpression | YieldExpression | SpreadElementExpression | NonNullExpression>node).expression, f, result);
+                result = reduceNode((<ParenthesizedExpression | DeleteExpression | TypeOfExpression | VoidExpression | AwaitExpression | YieldExpression | SpreadExpression | NonNullExpression>node).expression, f, result);
                 break;
 
             case SyntaxKind.PrefixUnaryExpression:
@@ -869,9 +869,9 @@ namespace ts {
                 return updateYield(<YieldExpression>node,
                     visitNode((<YieldExpression>node).expression, visitor, isExpression));
 
-            case SyntaxKind.SpreadElementExpression:
-                return updateSpread(<SpreadElementExpression>node,
-                    visitNode((<SpreadElementExpression>node).expression, visitor, isExpression));
+            case SyntaxKind.SpreadExpression:
+                return updateSpread(<SpreadExpression>node,
+                    visitNode((<SpreadExpression>node).expression, visitor, isExpression));
 
             case SyntaxKind.ClassExpression:
                 return updateClassExpression(<ClassExpression>node,
@@ -1357,4 +1357,4 @@ namespace ts {
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/services/breakpoints.ts b/src/services/breakpoints.ts
index bf7fb981daaca..f1cc233e67680 100644
--- a/src/services/breakpoints.ts
+++ b/src/services/breakpoints.ts
@@ -264,7 +264,7 @@ namespace ts.BreakpointResolver {
                         // a or ...c  or d: x from
                         // [a, b, ...c] or { a, b } or { d: x } from destructuring pattern
                         if ((node.kind === SyntaxKind.Identifier ||
-                            node.kind == SyntaxKind.SpreadElementExpression ||
+                            node.kind == SyntaxKind.SpreadExpression ||
                             node.kind === SyntaxKind.PropertyAssignment ||
                             node.kind === SyntaxKind.ShorthandPropertyAssignment) &&
                             isArrayLiteralOrObjectLiteralDestructuringPattern(node.parent)) {
diff --git a/src/services/utilities.ts b/src/services/utilities.ts
index d1f3a54563f91..e5de4437a5eca 100644
--- a/src/services/utilities.ts
+++ b/src/services/utilities.ts
@@ -530,8 +530,8 @@ namespace ts {
             case SyntaxKind.DeleteExpression:
             case SyntaxKind.VoidExpression:
             case SyntaxKind.YieldExpression:
-            case SyntaxKind.SpreadElementExpression:
-                const unaryWordExpression = (<TypeOfExpression | DeleteExpression | VoidExpression | YieldExpression | SpreadElementExpression>n);
+            case SyntaxKind.SpreadExpression:
+                const unaryWordExpression = n as (TypeOfExpression | DeleteExpression | VoidExpression | YieldExpression | SpreadExpression);
                 return isCompletedNode(unaryWordExpression.expression, sourceFile);
 
             case SyntaxKind.TaggedTemplateExpression:

From 9a7ebb0ac5eadf9630577b11eb0064c04ed6cd44 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 26 Sep 2016 11:53:11 -0700
Subject: [PATCH 009/224] Change new file to use CRLF

What's YOUR favourite thing about Mars, Beartato?
---
 src/compiler/transformers/experimental.ts | 160 +++++++++++-----------
 1 file changed, 80 insertions(+), 80 deletions(-)

diff --git a/src/compiler/transformers/experimental.ts b/src/compiler/transformers/experimental.ts
index 85af37709c744..2ee623db43aed 100644
--- a/src/compiler/transformers/experimental.ts
+++ b/src/compiler/transformers/experimental.ts
@@ -1,80 +1,80 @@
-/// <reference path="../factory.ts" />
-/// <reference path="../visitor.ts" />
-
-/*@internal*/
-namespace ts {
-    export function transformExperimental(context: TransformationContext) {
-        return transformSourceFile;
-
-        function transformSourceFile(node: SourceFile) {
-            return visitEachChild(node, visitor, context);
-        }
-
-        function visitor(node: Node): VisitResult<Node> {
-            if (node.transformFlags & TransformFlags.Experimental) {
-                return visitorWorker(node);
-            }
-            else if (node.transformFlags & TransformFlags.ContainsExperimental) {
-                return visitEachChild(node, visitor, context);
-            }
-            else {
-                return node;
-            }
-        }
-
-        function visitorWorker(node: Node): VisitResult<Node> {
-            switch (node.kind) {
-                case SyntaxKind.ObjectLiteralExpression:
-                    return visitObjectLiteralExpression(node as ObjectLiteralExpression);
-                default:
-                    Debug.failBadSyntaxKind(node);
-                    return visitEachChild(node, visitor, context);
-            }
-        }
-
-        function chunkObjectLiteralElements(elements: ObjectLiteralElement[]): Expression[] {
-            let chunkObject: (ShorthandPropertyAssignment | PropertyAssignment)[];
-            const objects: Expression[] = [];
-            for (const e of elements) {
-                if (e.kind === SyntaxKind.SpreadElementExpression) {
-                    if (chunkObject) {
-                        objects.push(createObjectLiteral(chunkObject));
-                        chunkObject = undefined;
-                    }
-                    const target = (e as SpreadElementExpression).expression;
-                    objects.push(visitNode(target, visitor, isExpression));
-                }
-                else {
-                    if (!chunkObject) {
-                        chunkObject = [];
-                    }
-                    if (e.kind === SyntaxKind.PropertyAssignment) {
-                        const p = e as PropertyAssignment;
-                        chunkObject.push(createPropertyAssignment(p.name, visitNode(p.initializer, visitor, isExpression)));
-                    }
-                    else {
-                        chunkObject.push(e as ShorthandPropertyAssignment);
-                    }
-                }
-            }
-            if (chunkObject) {
-                objects.push(createObjectLiteral(chunkObject));
-            }
-
-            return objects;
-        }
-
-        function visitObjectLiteralExpression(node: ObjectLiteralExpression): Expression {
-            // spread elements emit like so:
-            // non-spread elements are chunked together into object literals, and then all are passed to __assign:
-            //     { a, ...o, b } => __assign({a}, o, {b});
-            // If the first element is a spread element, then the first argument to __assign is {}:
-            //     { ...o, a, b, ...o2 } => __assign({}, o, {a, b}, o2)
-            const objects = chunkObjectLiteralElements(node.properties);
-            if (objects.length && objects[0].kind !== SyntaxKind.ObjectLiteralExpression) {
-                objects.unshift(createObjectLiteral());
-            }
-            return createCall(createIdentifier("__assign"), undefined, objects);
-        }
-    }
-}
+/// <reference path="../factory.ts" />
+/// <reference path="../visitor.ts" />
+
+/*@internal*/
+namespace ts {
+    export function transformExperimental(context: TransformationContext) {
+        return transformSourceFile;
+
+        function transformSourceFile(node: SourceFile) {
+            return visitEachChild(node, visitor, context);
+        }
+
+        function visitor(node: Node): VisitResult<Node> {
+            if (node.transformFlags & TransformFlags.Experimental) {
+                return visitorWorker(node);
+            }
+            else if (node.transformFlags & TransformFlags.ContainsExperimental) {
+                return visitEachChild(node, visitor, context);
+            }
+            else {
+                return node;
+            }
+        }
+
+        function visitorWorker(node: Node): VisitResult<Node> {
+            switch (node.kind) {
+                case SyntaxKind.ObjectLiteralExpression:
+                    return visitObjectLiteralExpression(node as ObjectLiteralExpression);
+                default:
+                    Debug.failBadSyntaxKind(node);
+                    return visitEachChild(node, visitor, context);
+            }
+        }
+
+        function chunkObjectLiteralElements(elements: ObjectLiteralElement[]): Expression[] {
+            let chunkObject: (ShorthandPropertyAssignment | PropertyAssignment)[];
+            const objects: Expression[] = [];
+            for (const e of elements) {
+                if (e.kind === SyntaxKind.SpreadElementExpression) {
+                    if (chunkObject) {
+                        objects.push(createObjectLiteral(chunkObject));
+                        chunkObject = undefined;
+                    }
+                    const target = (e as SpreadElementExpression).expression;
+                    objects.push(visitNode(target, visitor, isExpression));
+                }
+                else {
+                    if (!chunkObject) {
+                        chunkObject = [];
+                    }
+                    if (e.kind === SyntaxKind.PropertyAssignment) {
+                        const p = e as PropertyAssignment;
+                        chunkObject.push(createPropertyAssignment(p.name, visitNode(p.initializer, visitor, isExpression)));
+                    }
+                    else {
+                        chunkObject.push(e as ShorthandPropertyAssignment);
+                    }
+                }
+            }
+            if (chunkObject) {
+                objects.push(createObjectLiteral(chunkObject));
+            }
+
+            return objects;
+        }
+
+        function visitObjectLiteralExpression(node: ObjectLiteralExpression): Expression {
+            // spread elements emit like so:
+            // non-spread elements are chunked together into object literals, and then all are passed to __assign:
+            //     { a, ...o, b } => __assign({a}, o, {b});
+            // If the first element is a spread element, then the first argument to __assign is {}:
+            //     { ...o, a, b, ...o2 } => __assign({}, o, {a, b}, o2)
+            const objects = chunkObjectLiteralElements(node.properties);
+            if (objects.length && objects[0].kind !== SyntaxKind.ObjectLiteralExpression) {
+                objects.unshift(createObjectLiteral());
+            }
+            return createCall(createIdentifier("__assign"), undefined, objects);
+        }
+    }
+}

From cfdf75176863a08fd9112649d9c5a34acd7e6505 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 27 Sep 2016 10:30:13 -0700
Subject: [PATCH 010/224] Make index signatures work on spread types

Previously, they worked when they came from a spread type but not when
written in the object literal itself.
---
 src/compiler/checker.ts | 59 ++++++++++++++++++++++++-----------------
 1 file changed, 34 insertions(+), 25 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 1f31d58b19709..66a5d9fc4153d 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2321,6 +2321,9 @@ namespace ts {
                             printFollowingPunctuation = true;
                         }
                     }
+                    const resolved = resolveStructuredTypeMembers(type);
+                    writeIndexSignature(resolved.stringIndexInfo, SyntaxKind.StringKeyword);
+                    writeIndexSignature(resolved.numberIndexInfo, SyntaxKind.NumberKeyword);
                     writer.decreaseIndent();
                     if (printFollowingPunctuation) {
                         writeSpace(writer);
@@ -4306,15 +4309,14 @@ namespace ts {
 
         function resolveSpreadTypeMembers(type: SpreadType) {
             // The members and properties collections are empty for spread types. To get all properties of an
-            // spread type use getPropertiesOfType (only the language service uses this).
-            let stringIndexInfo: IndexInfo = undefined;
-            let numberIndexInfo: IndexInfo = undefined;
+            // spread type use getPropertiesOfType.
+            let stringIndexInfo: IndexInfo = getIndexInfoOfSymbol(type.symbol, IndexKind.String);
+            let numberIndexInfo: IndexInfo = getIndexInfoOfSymbol(type.symbol, IndexKind.Number);
             for (let i = type.types.length - 1; i > -1; i--) {
                 const t = type.types[i];
-                stringIndexInfo = intersectIndexInfos(stringIndexInfo, getIndexInfoOfType(t, IndexKind.String));
-                numberIndexInfo = intersectIndexInfos(numberIndexInfo, getIndexInfoOfType(t, IndexKind.Number));
-                if (!t.symbol || !(t.symbol.flags & SymbolFlags.Optional)) {
-                    break;
+                if (!t.isDeclaredProperty) {
+                    stringIndexInfo = intersectIndexInfos(stringIndexInfo, getIndexInfoOfType(t, IndexKind.String));
+                    numberIndexInfo = intersectIndexInfos(numberIndexInfo, getIndexInfoOfType(t, IndexKind.Number));
                 }
             }
             setObjectTypeMembers(type, emptySymbols, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
@@ -4545,6 +4547,9 @@ namespace ts {
             result.containingType = containingType;
             result.hasCommonType = hasCommonType;
             result.declarations = declarations;
+            if (declarations.length) {
+                result.valueDeclaration = declarations[0];
+            }
             result.isReadonly = isReadonly;
             result.type = containingType.flags & TypeFlags.Intersection ? getIntersectionType(propTypes) : getUnionType(propTypes);
             return result;
@@ -5059,7 +5064,7 @@ namespace ts {
             const declaration = getIndexDeclarationOfSymbol(symbol, kind);
             if (declaration) {
                 return createIndexInfo(declaration.type ? getTypeFromTypeNode(declaration.type) : anyType,
-                    (getModifierFlags(declaration) & ModifierFlags.Readonly) !== 0, declaration);
+                                       (getModifierFlags(declaration) & ModifierFlags.Readonly) !== 0, declaration);
             }
             return undefined;
         }
@@ -5683,11 +5688,15 @@ namespace ts {
                             }
                             spreads.push(getTypeFromTypeNode((member as SpreadTypeElement).type) as SpreadElementType);
                         }
-                        else if (member.kind !== SyntaxKind.CallSignature && member.kind !== SyntaxKind.ConstructSignature) {
-                            // note that spread types don't include call and construct signatures
+                        else if (member.kind !== SyntaxKind.CallSignature &&
+                                 member.kind !== SyntaxKind.ConstructSignature &&
+                                 member.kind !== SyntaxKind.IndexSignature) {
+                            // note that spread types don't include call and construct signatures, and index signatures are resolved later
                             const flags = SymbolFlags.Property | SymbolFlags.Transient | (member.questionToken ? SymbolFlags.Optional : 0);
                             const text = getTextOfPropertyName(member.name);
                             const symbol = <TransientSymbol>createSymbol(flags, text);
+                            symbol.declarations = [member];
+                            symbol.valueDeclaration = member;
                             symbol.type = getTypeFromTypeNodeNoAlias((member as IndexSignatureDeclaration | PropertySignature | MethodSignature).type);
                             if (!members) {
                                 members = createMap<Symbol>();
@@ -10458,7 +10467,7 @@ namespace ts {
                 }
                 else if (memberDecl.kind === SyntaxKind.SpreadElementExpression) {
                     if (propertiesArray.length > 0) {
-                        const t = createObjectLiteralType(node, hasComputedStringProperty, hasComputedNumberProperty, propertiesArray, propertiesTable, typeFlags, patternWithComputedProperties, inDestructuringPattern) as SpreadElementType;
+                        const t = createObjectLiteralType() as SpreadElementType;
                         t.isDeclaredProperty = true;
                         spreads.push(t);
                         propertiesArray = [];
@@ -10510,7 +10519,7 @@ namespace ts {
 
             if (spreads.length > 0) {
                 if (propertiesArray.length > 0) {
-                    const t = createObjectLiteralType(node, hasComputedStringProperty, hasComputedNumberProperty, propertiesArray, propertiesTable, typeFlags, patternWithComputedProperties, inDestructuringPattern) as SpreadElementType;
+                    const t = createObjectLiteralType() as SpreadElementType;
                     t.isDeclaredProperty = true;
                     spreads.push(t);
                 }
@@ -10520,20 +10529,20 @@ namespace ts {
                 return spread;
             }
 
-            return createObjectLiteralType(node, hasComputedStringProperty, hasComputedNumberProperty, propertiesArray, propertiesTable, typeFlags, patternWithComputedProperties, inDestructuringPattern);
-        }
-
-        function createObjectLiteralType(node: ObjectLiteralExpression, hasComputedStringProperty: boolean, hasComputedNumberProperty: boolean, propertiesArray: Symbol[], propertiesTable: Map<Symbol>, typeFlags: TypeFlags, patternWithComputedProperties: boolean, inDestructuringPattern: boolean) {
-            const stringIndexInfo = hasComputedStringProperty ? getObjectLiteralIndexInfo(node, propertiesArray, IndexKind.String) : undefined;
-            const numberIndexInfo = hasComputedNumberProperty ? getObjectLiteralIndexInfo(node, propertiesArray, IndexKind.Number) : undefined;
-            const result = createAnonymousType(node.symbol, propertiesTable, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
-            const freshObjectLiteralFlag = compilerOptions.suppressExcessPropertyErrors ? 0 : TypeFlags.FreshObjectLiteral;
-            result.flags |= TypeFlags.ObjectLiteral | TypeFlags.ContainsObjectLiteral | freshObjectLiteralFlag | (typeFlags & TypeFlags.PropagatingFlags) | (patternWithComputedProperties ? TypeFlags.ObjectLiteralPatternWithComputedProperties : 0);
-            if (inDestructuringPattern) {
-                result.pattern = node;
+            return createObjectLiteralType();
+            function createObjectLiteralType() {
+                const stringIndexInfo = hasComputedStringProperty ? getObjectLiteralIndexInfo(node, propertiesArray, IndexKind.String) : undefined;
+                const numberIndexInfo = hasComputedNumberProperty ? getObjectLiteralIndexInfo(node, propertiesArray, IndexKind.Number) : undefined;
+                const result = createAnonymousType(node.symbol, propertiesTable, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
+                const freshObjectLiteralFlag = compilerOptions.suppressExcessPropertyErrors ? 0 : TypeFlags.FreshObjectLiteral;
+                result.flags |= TypeFlags.ObjectLiteral | TypeFlags.ContainsObjectLiteral | freshObjectLiteralFlag | (typeFlags & TypeFlags.PropagatingFlags) | (patternWithComputedProperties ? TypeFlags.ObjectLiteralPatternWithComputedProperties : 0);
+                if (inDestructuringPattern) {
+                    result.pattern = node;
+                }
+                return result;
             }
-            return result;
-        }
+
+       }
 
         function checkJsxSelfClosingElement(node: JsxSelfClosingElement) {
             checkJsxOpeningLikeElement(node);

From d6e414ce5b3e9532dd05651854f1d2f694de6e8c Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 27 Sep 2016 10:33:50 -0700
Subject: [PATCH 011/224] Test spread type index signatures

---
 .../reference/objectSpreadIndexSignature.js   | 29 ++++++++++
 .../objectSpreadIndexSignature.symbols        | 51 +++++++++++++++++
 .../objectSpreadIndexSignature.types          | 57 +++++++++++++++++++
 .../spread/objectSpreadIndexSignature.ts      | 14 +++++
 4 files changed, 151 insertions(+)
 create mode 100644 tests/baselines/reference/objectSpreadIndexSignature.js
 create mode 100644 tests/baselines/reference/objectSpreadIndexSignature.symbols
 create mode 100644 tests/baselines/reference/objectSpreadIndexSignature.types
 create mode 100644 tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts

diff --git a/tests/baselines/reference/objectSpreadIndexSignature.js b/tests/baselines/reference/objectSpreadIndexSignature.js
new file mode 100644
index 0000000000000..c4a0d6b90d8a8
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadIndexSignature.js
@@ -0,0 +1,29 @@
+//// [objectSpreadIndexSignature.ts]
+class C {
+    a: number;
+    c: boolean;
+}
+let c: { ...C, b: string, c?: string, [n: number]: string };
+let n: number = c.a;
+let s: string = c[12];
+interface Indexed {
+    [n: number]: string;
+    a: boolean;
+}
+let i: { ...Indexed, b: string };
+s = i[101];
+s = i.b;
+
+
+//// [objectSpreadIndexSignature.js]
+var C = (function () {
+    function C() {
+    }
+    return C;
+}());
+var c;
+var n = c.a;
+var s = c[12];
+var i;
+s = i[101];
+s = i.b;
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.symbols b/tests/baselines/reference/objectSpreadIndexSignature.symbols
new file mode 100644
index 0000000000000..fee1e862adea6
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadIndexSignature.symbols
@@ -0,0 +1,51 @@
+=== tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts ===
+class C {
+>C : Symbol(C, Decl(objectSpreadIndexSignature.ts, 0, 0))
+
+    a: number;
+>a : Symbol(C.a, Decl(objectSpreadIndexSignature.ts, 0, 9))
+
+    c: boolean;
+>c : Symbol(C.c, Decl(objectSpreadIndexSignature.ts, 1, 14))
+}
+let c: { ...C, b: string, c?: string, [n: number]: string };
+>c : Symbol(c, Decl(objectSpreadIndexSignature.ts, 4, 3))
+>C : Symbol(C, Decl(objectSpreadIndexSignature.ts, 0, 0))
+>b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 4, 14))
+>c : Symbol(c, Decl(objectSpreadIndexSignature.ts, 4, 25))
+>n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 4, 39))
+
+let n: number = c.a;
+>n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 5, 3))
+>c.a : Symbol(C.a, Decl(objectSpreadIndexSignature.ts, 0, 9))
+>c : Symbol(c, Decl(objectSpreadIndexSignature.ts, 4, 3))
+>a : Symbol(C.a, Decl(objectSpreadIndexSignature.ts, 0, 9))
+
+let s: string = c[12];
+>s : Symbol(s, Decl(objectSpreadIndexSignature.ts, 6, 3))
+>c : Symbol(c, Decl(objectSpreadIndexSignature.ts, 4, 3))
+
+interface Indexed {
+>Indexed : Symbol(Indexed, Decl(objectSpreadIndexSignature.ts, 6, 22))
+
+    [n: number]: string;
+>n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 8, 5))
+
+    a: boolean;
+>a : Symbol(Indexed.a, Decl(objectSpreadIndexSignature.ts, 8, 24))
+}
+let i: { ...Indexed, b: string };
+>i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 11, 3))
+>Indexed : Symbol(Indexed, Decl(objectSpreadIndexSignature.ts, 6, 22))
+>b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 11, 20))
+
+s = i[101];
+>s : Symbol(s, Decl(objectSpreadIndexSignature.ts, 6, 3))
+>i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 11, 3))
+
+s = i.b;
+>s : Symbol(s, Decl(objectSpreadIndexSignature.ts, 6, 3))
+>i.b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 11, 20))
+>i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 11, 3))
+>b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 11, 20))
+
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.types b/tests/baselines/reference/objectSpreadIndexSignature.types
new file mode 100644
index 0000000000000..9adbb349da2d2
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadIndexSignature.types
@@ -0,0 +1,57 @@
+=== tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts ===
+class C {
+>C : C
+
+    a: number;
+>a : number
+
+    c: boolean;
+>c : boolean
+}
+let c: { ...C, b: string, c?: string, [n: number]: string };
+>c : { ...C; b: string; c?: string; [n: number]: string; }
+>C : C
+>b : string
+>c : string
+>n : number
+
+let n: number = c.a;
+>n : number
+>c.a : number
+>c : { ...C; b: string; c?: string; [n: number]: string; }
+>a : number
+
+let s: string = c[12];
+>s : string
+>c[12] : string
+>c : { ...C; b: string; c?: string; [n: number]: string; }
+>12 : 12
+
+interface Indexed {
+>Indexed : Indexed
+
+    [n: number]: string;
+>n : number
+
+    a: boolean;
+>a : boolean
+}
+let i: { ...Indexed, b: string };
+>i : { ...Indexed; b: string; [n: number]: string; }
+>Indexed : Indexed
+>b : string
+
+s = i[101];
+>s = i[101] : string
+>s : string
+>i[101] : string
+>i : { ...Indexed; b: string; [n: number]: string; }
+>101 : 101
+
+s = i.b;
+>s = i.b : string
+>s : string
+>i.b : string
+>i : { ...Indexed; b: string; [n: number]: string; }
+>b : string
+
diff --git a/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts b/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
new file mode 100644
index 0000000000000..11ba545008504
--- /dev/null
+++ b/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
@@ -0,0 +1,14 @@
+class C {
+    a: number;
+    c: boolean;
+}
+let c: { ...C, b: string, c?: string, [n: number]: string };
+let n: number = c.a;
+let s: string = c[12];
+interface Indexed {
+    [n: number]: string;
+    a: boolean;
+}
+let i: { ...Indexed, b: string };
+s = i[101];
+s = i.b;

From 429b0d95ca54538cabdd09e59eeca71661fe72d9 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 27 Sep 2016 11:05:12 -0700
Subject: [PATCH 012/224] Union multiple spread index signatures

---
 src/compiler/checker.ts | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 66a5d9fc4153d..e1e7cce4df41c 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2321,6 +2321,8 @@ namespace ts {
                             printFollowingPunctuation = true;
                         }
                     }
+                    // TODO: Only print if this is directly on the type -- not on the subtype somewhere.
+                    // (This is not crucial, though, since the extra info *might* be nice.)
                     const resolved = resolveStructuredTypeMembers(type);
                     writeIndexSignature(resolved.stringIndexInfo, SyntaxKind.StringKeyword);
                     writeIndexSignature(resolved.numberIndexInfo, SyntaxKind.NumberKeyword);
@@ -4291,6 +4293,11 @@ namespace ts {
                 getIntersectionType([info1.type, info2.type]), info1.isReadonly && info2.isReadonly);
         }
 
+        function unionIndexInfos(info1: IndexInfo, info2: IndexInfo): IndexInfo {
+            return !info1 ? info2 : !info2 ? info1 : createIndexInfo(
+                getUnionType([info1.type, info2.type]), info1.isReadonly || info2.isReadonly);
+        }
+
         function resolveIntersectionTypeMembers(type: IntersectionType) {
             // The members and properties collections are empty for intersection types. To get all properties of an
             // intersection type use getPropertiesOfType (only the language service uses this).
@@ -4315,8 +4322,8 @@ namespace ts {
             for (let i = type.types.length - 1; i > -1; i--) {
                 const t = type.types[i];
                 if (!t.isDeclaredProperty) {
-                    stringIndexInfo = intersectIndexInfos(stringIndexInfo, getIndexInfoOfType(t, IndexKind.String));
-                    numberIndexInfo = intersectIndexInfos(numberIndexInfo, getIndexInfoOfType(t, IndexKind.Number));
+                    stringIndexInfo = unionIndexInfos(stringIndexInfo, getIndexInfoOfType(t, IndexKind.String));
+                    numberIndexInfo = unionIndexInfos(numberIndexInfo, getIndexInfoOfType(t, IndexKind.Number));
                 }
             }
             setObjectTypeMembers(type, emptySymbols, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
@@ -16839,7 +16846,9 @@ namespace ts {
                 // perform property check if property or indexer is declared in 'type'
                 // this allows to rule out cases when both property and indexer are inherited from the base class
                 let errorNode: Node;
-                if (prop.valueDeclaration.name.kind === SyntaxKind.ComputedPropertyName || prop.parent === containingType.symbol) {
+                    if (prop.valueDeclaration.name.kind === SyntaxKind.ComputedPropertyName ||
+                        prop.parent === containingType.symbol ||
+                        containingType.flags & TypeFlags.Spread) {
                     errorNode = prop.valueDeclaration;
                 }
                 else if (indexDeclaration) {

From 78420adfcdf67a9e79025edee9a33e886c72ba94 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 27 Sep 2016 11:05:58 -0700
Subject: [PATCH 013/224] Test object spread index signatures

---
 .../reference/objectSpreadIndexSignature.js   | 22 ++++---
 .../objectSpreadIndexSignature.symbols        | 34 ++++++++---
 .../objectSpreadIndexSignature.types          | 58 +++++++++++++------
 .../spread/objectSpreadIndexSignature.ts      | 16 +++--
 4 files changed, 93 insertions(+), 37 deletions(-)

diff --git a/tests/baselines/reference/objectSpreadIndexSignature.js b/tests/baselines/reference/objectSpreadIndexSignature.js
index c4a0d6b90d8a8..b5ec35277e0c3 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.js
+++ b/tests/baselines/reference/objectSpreadIndexSignature.js
@@ -7,12 +7,18 @@ let c: { ...C, b: string, c?: string, [n: number]: string };
 let n: number = c.a;
 let s: string = c[12];
 interface Indexed {
-    [n: number]: string;
-    a: boolean;
+    [n: string]: number;
+    a: number;
+}
+let i: { ...Indexed, b: number };
+n = i[101];
+n = i.b;
+interface Indexed2 {
+    [n: string]: boolean;
+    c: boolean;
 }
-let i: { ...Indexed, b: string };
-s = i[101];
-s = i.b;
+let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
+let nb: number | boolean = ii[1001];
 
 
 //// [objectSpreadIndexSignature.js]
@@ -25,5 +31,7 @@ var c;
 var n = c.a;
 var s = c[12];
 var i;
-s = i[101];
-s = i.b;
+n = i[101];
+n = i.b;
+var ii;
+var nb = ii[1001];
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.symbols b/tests/baselines/reference/objectSpreadIndexSignature.symbols
index fee1e862adea6..a3510f9865830 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.symbols
+++ b/tests/baselines/reference/objectSpreadIndexSignature.symbols
@@ -28,24 +28,44 @@ let s: string = c[12];
 interface Indexed {
 >Indexed : Symbol(Indexed, Decl(objectSpreadIndexSignature.ts, 6, 22))
 
-    [n: number]: string;
+    [n: string]: number;
 >n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 8, 5))
 
-    a: boolean;
+    a: number;
 >a : Symbol(Indexed.a, Decl(objectSpreadIndexSignature.ts, 8, 24))
 }
-let i: { ...Indexed, b: string };
+let i: { ...Indexed, b: number };
 >i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 11, 3))
 >Indexed : Symbol(Indexed, Decl(objectSpreadIndexSignature.ts, 6, 22))
 >b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 11, 20))
 
-s = i[101];
->s : Symbol(s, Decl(objectSpreadIndexSignature.ts, 6, 3))
+n = i[101];
+>n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 5, 3))
 >i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 11, 3))
 
-s = i.b;
->s : Symbol(s, Decl(objectSpreadIndexSignature.ts, 6, 3))
+n = i.b;
+>n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 5, 3))
 >i.b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 11, 20))
 >i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 11, 3))
 >b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 11, 20))
 
+interface Indexed2 {
+>Indexed2 : Symbol(Indexed2, Decl(objectSpreadIndexSignature.ts, 13, 8))
+
+    [n: string]: boolean;
+>n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 15, 5))
+
+    c: boolean;
+>c : Symbol(Indexed2.c, Decl(objectSpreadIndexSignature.ts, 15, 25))
+}
+let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
+>ii : Symbol(ii, Decl(objectSpreadIndexSignature.ts, 18, 3))
+>Indexed : Symbol(Indexed, Decl(objectSpreadIndexSignature.ts, 6, 22))
+>Indexed2 : Symbol(Indexed2, Decl(objectSpreadIndexSignature.ts, 13, 8))
+>b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 18, 34))
+>d : Symbol(d, Decl(objectSpreadIndexSignature.ts, 18, 46))
+
+let nb: number | boolean = ii[1001];
+>nb : Symbol(nb, Decl(objectSpreadIndexSignature.ts, 19, 3))
+>ii : Symbol(ii, Decl(objectSpreadIndexSignature.ts, 18, 3))
+
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.types b/tests/baselines/reference/objectSpreadIndexSignature.types
index 9adbb349da2d2..9a31b0c44512b 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.types
+++ b/tests/baselines/reference/objectSpreadIndexSignature.types
@@ -30,28 +30,50 @@ let s: string = c[12];
 interface Indexed {
 >Indexed : Indexed
 
-    [n: number]: string;
->n : number
+    [n: string]: number;
+>n : string
 
-    a: boolean;
->a : boolean
+    a: number;
+>a : number
 }
-let i: { ...Indexed, b: string };
->i : { ...Indexed; b: string; [n: number]: string; }
+let i: { ...Indexed, b: number };
+>i : { ...Indexed; b: number; [n: string]: number; }
 >Indexed : Indexed
->b : string
+>b : number
 
-s = i[101];
->s = i[101] : string
->s : string
->i[101] : string
->i : { ...Indexed; b: string; [n: number]: string; }
+n = i[101];
+>n = i[101] : number
+>n : number
+>i[101] : number
+>i : { ...Indexed; b: number; [n: string]: number; }
 >101 : 101
 
-s = i.b;
->s = i.b : string
->s : string
->i.b : string
->i : { ...Indexed; b: string; [n: number]: string; }
->b : string
+n = i.b;
+>n = i.b : number
+>n : number
+>i.b : number
+>i : { ...Indexed; b: number; [n: string]: number; }
+>b : number
+
+interface Indexed2 {
+>Indexed2 : Indexed2
+
+    [n: string]: boolean;
+>n : string
+
+    c: boolean;
+>c : boolean
+}
+let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
+>ii : { ...Indexed; ...Indexed2; b: boolean; d: number; [x: string]: number | boolean; }
+>Indexed : Indexed
+>Indexed2 : Indexed2
+>b : boolean
+>d : number
+
+let nb: number | boolean = ii[1001];
+>nb : number | boolean
+>ii[1001] : number | boolean
+>ii : { ...Indexed; ...Indexed2; b: boolean; d: number; [x: string]: number | boolean; }
+>1001 : 1001
 
diff --git a/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts b/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
index 11ba545008504..d6f9f511c7b9e 100644
--- a/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
@@ -6,9 +6,15 @@ let c: { ...C, b: string, c?: string, [n: number]: string };
 let n: number = c.a;
 let s: string = c[12];
 interface Indexed {
-    [n: number]: string;
-    a: boolean;
+    [n: string]: number;
+    a: number;
+}
+let i: { ...Indexed, b: number };
+n = i[101];
+n = i.b;
+interface Indexed2 {
+    [n: string]: boolean;
+    c: boolean;
 }
-let i: { ...Indexed, b: string };
-s = i[101];
-s = i.b;
+let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
+let nb: number | boolean = ii[1001];

From 7e7a26a3581c223f57f161dbc8f71ed4ac856590 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 27 Sep 2016 16:15:52 -0700
Subject: [PATCH 014/224] Spreads w/a single type parameter assignable to that
 type parameter

---
 src/compiler/checker.ts | 47 ++++++++++++++++++++++++++++-------------
 1 file changed, 32 insertions(+), 15 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index e1e7cce4df41c..209598259ebc5 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2321,8 +2321,6 @@ namespace ts {
                             printFollowingPunctuation = true;
                         }
                     }
-                    // TODO: Only print if this is directly on the type -- not on the subtype somewhere.
-                    // (This is not crucial, though, since the extra info *might* be nice.)
                     const resolved = resolveStructuredTypeMembers(type);
                     writeIndexSignature(resolved.stringIndexInfo, SyntaxKind.StringKeyword);
                     writeIndexSignature(resolved.numberIndexInfo, SyntaxKind.NumberKeyword);
@@ -6656,23 +6654,42 @@ namespace ts {
                     }
                 }
 
-                if (source.flags & TypeFlags.Spread && target.flags & TypeFlags.Spread) {
-                    const sourceParameters = filter((source as SpreadType).types, t => !!(t.flags & TypeFlags.TypeParameter));
-                    const targetParameters = filter((target as SpreadType).types, t => !!(t.flags & TypeFlags.TypeParameter));
-                    if (sourceParameters.length !== targetParameters.length) {
-                        reportRelationError(headMessage, source, target);
-                        return Ternary.False;
+                if (source.flags & TypeFlags.Spread) {
+                    if (target.flags & TypeFlags.TypeParameter) {
+                        let hasTypeParameter = false;
+                        let typeParametersAreEqual = true;
+                        for (const t of (source as SpreadType).types) {
+                            if (t.flags & TypeFlags.TypeParameter) {
+                                hasTypeParameter = true;
+                                if (t !== target) {
+                                    typeParametersAreEqual = false;
+                                    break;
+                                }
+                            }
+                        }
+                        if (hasTypeParameter && typeParametersAreEqual) {
+                            errorInfo = saveErrorInfo;
+                            return Ternary.True;
+                        }
                     }
-                    for (let i = 0; i < sourceParameters.length; i++) {
-                        if (sourceParameters[i].symbol !== targetParameters[i].symbol) {
+                    else if (target.flags & TypeFlags.Spread) {
+                        const sourceParameters = filter((source as SpreadType).types, t => !!(t.flags & TypeFlags.TypeParameter));
+                        const targetParameters = filter((target as SpreadType).types, t => !!(t.flags & TypeFlags.TypeParameter));
+                        if (sourceParameters.length !== targetParameters.length) {
                             reportRelationError(headMessage, source, target);
                             return Ternary.False;
                         }
-                    }
-                    const reportStructuralErrors = reportErrors && errorInfo === saveErrorInfo;
-                    if (result = objectTypeRelatedTo(source, source, target, reportStructuralErrors)) {
-                        errorInfo = saveErrorInfo;
-                        return result;
+                        for (let i = 0; i < sourceParameters.length; i++) {
+                            if (sourceParameters[i].symbol !== targetParameters[i].symbol) {
+                                reportRelationError(headMessage, source, target);
+                                return Ternary.False;
+                            }
+                        }
+                        const reportStructuralErrors = reportErrors && errorInfo === saveErrorInfo;
+                        if (result = objectTypeRelatedTo(source, source, target, reportStructuralErrors)) {
+                            errorInfo = saveErrorInfo;
+                            return result;
+                        }
                     }
                 }
 

From 0f773c5673d85633d321fb4cb5cbed94739d3c78 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 27 Sep 2016 16:17:14 -0700
Subject: [PATCH 015/224] Add object spread scenario tests

---
 .../reference/objectSpreadScenarios.js        |  45 ++++++++
 .../reference/objectSpreadScenarios.symbols   |  84 ++++++++++++++
 .../reference/objectSpreadScenarios.types     | 106 ++++++++++++++++++
 .../types/spread/objectSpreadScenarios.ts     |  17 +++
 4 files changed, 252 insertions(+)
 create mode 100644 tests/baselines/reference/objectSpreadScenarios.js
 create mode 100644 tests/baselines/reference/objectSpreadScenarios.symbols
 create mode 100644 tests/baselines/reference/objectSpreadScenarios.types
 create mode 100644 tests/cases/conformance/types/spread/objectSpreadScenarios.ts

diff --git a/tests/baselines/reference/objectSpreadScenarios.js b/tests/baselines/reference/objectSpreadScenarios.js
new file mode 100644
index 0000000000000..ae0e2f6c425ef
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadScenarios.js
@@ -0,0 +1,45 @@
+//// [objectSpreadScenarios.ts]
+interface A1 { a: boolean }
+interface B1 { b: number };
+function override<U>(initial: U, override: U): U {
+    return { ...initial, ...override };
+}
+function update<U>(this: { u: U }, override: U): void {
+    this.u = { ...this.u, ...override };
+}
+function mixin<T, U>(one: T, two: U): { ...T, ...U } {
+    return { ...one, ...two };
+}
+let a1: A1 = { a: true };
+let b1: B1 = { b: 101 };
+a1 = override(a1, { a: false });
+let host = { u: a1, update };
+host.update({ a: false });
+let mixed = mixin(a1, b1);
+
+
+//// [objectSpreadScenarios.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+;
+function override(initial, override) {
+    return __assign({}, initial, override);
+}
+function update(override) {
+    this.u = __assign({}, this.u, override);
+}
+function mixin(one, two) {
+    return __assign({}, one, two);
+}
+var a1 = { a: true };
+var b1 = { b: 101 };
+a1 = override(a1, { a: false });
+var host = { u: a1, update: update };
+host.update({ a: false });
+var mixed = mixin(a1, b1);
diff --git a/tests/baselines/reference/objectSpreadScenarios.symbols b/tests/baselines/reference/objectSpreadScenarios.symbols
new file mode 100644
index 0000000000000..c8c18ca1e2f5b
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadScenarios.symbols
@@ -0,0 +1,84 @@
+=== tests/cases/conformance/types/spread/objectSpreadScenarios.ts ===
+interface A1 { a: boolean }
+>A1 : Symbol(A1, Decl(objectSpreadScenarios.ts, 0, 0))
+>a : Symbol(A1.a, Decl(objectSpreadScenarios.ts, 0, 14))
+
+interface B1 { b: number };
+>B1 : Symbol(B1, Decl(objectSpreadScenarios.ts, 0, 27))
+>b : Symbol(B1.b, Decl(objectSpreadScenarios.ts, 1, 14))
+
+function override<U>(initial: U, override: U): U {
+>override : Symbol(override, Decl(objectSpreadScenarios.ts, 1, 27))
+>U : Symbol(U, Decl(objectSpreadScenarios.ts, 2, 18))
+>initial : Symbol(initial, Decl(objectSpreadScenarios.ts, 2, 21))
+>U : Symbol(U, Decl(objectSpreadScenarios.ts, 2, 18))
+>override : Symbol(override, Decl(objectSpreadScenarios.ts, 2, 32))
+>U : Symbol(U, Decl(objectSpreadScenarios.ts, 2, 18))
+>U : Symbol(U, Decl(objectSpreadScenarios.ts, 2, 18))
+
+    return { ...initial, ...override };
+}
+function update<U>(this: { u: U }, override: U): void {
+>update : Symbol(update, Decl(objectSpreadScenarios.ts, 4, 1))
+>U : Symbol(U, Decl(objectSpreadScenarios.ts, 5, 16))
+>this : Symbol(this, Decl(objectSpreadScenarios.ts, 5, 19))
+>u : Symbol(u, Decl(objectSpreadScenarios.ts, 5, 26))
+>U : Symbol(U, Decl(objectSpreadScenarios.ts, 5, 16))
+>override : Symbol(override, Decl(objectSpreadScenarios.ts, 5, 34))
+>U : Symbol(U, Decl(objectSpreadScenarios.ts, 5, 16))
+
+    this.u = { ...this.u, ...override };
+>this.u : Symbol(u, Decl(objectSpreadScenarios.ts, 5, 26))
+>this : Symbol(this, Decl(objectSpreadScenarios.ts, 5, 19))
+>u : Symbol(u, Decl(objectSpreadScenarios.ts, 5, 26))
+>this.u : Symbol(u, Decl(objectSpreadScenarios.ts, 5, 26))
+>this : Symbol(this, Decl(objectSpreadScenarios.ts, 5, 19))
+>u : Symbol(u, Decl(objectSpreadScenarios.ts, 5, 26))
+}
+function mixin<T, U>(one: T, two: U): { ...T, ...U } {
+>mixin : Symbol(mixin, Decl(objectSpreadScenarios.ts, 7, 1))
+>T : Symbol(T, Decl(objectSpreadScenarios.ts, 8, 15))
+>U : Symbol(U, Decl(objectSpreadScenarios.ts, 8, 17))
+>one : Symbol(one, Decl(objectSpreadScenarios.ts, 8, 21))
+>T : Symbol(T, Decl(objectSpreadScenarios.ts, 8, 15))
+>two : Symbol(two, Decl(objectSpreadScenarios.ts, 8, 28))
+>U : Symbol(U, Decl(objectSpreadScenarios.ts, 8, 17))
+>T : Symbol(T, Decl(objectSpreadScenarios.ts, 8, 15))
+>U : Symbol(U, Decl(objectSpreadScenarios.ts, 8, 17))
+
+    return { ...one, ...two };
+}
+let a1: A1 = { a: true };
+>a1 : Symbol(a1, Decl(objectSpreadScenarios.ts, 11, 3))
+>A1 : Symbol(A1, Decl(objectSpreadScenarios.ts, 0, 0))
+>a : Symbol(a, Decl(objectSpreadScenarios.ts, 11, 14))
+
+let b1: B1 = { b: 101 };
+>b1 : Symbol(b1, Decl(objectSpreadScenarios.ts, 12, 3))
+>B1 : Symbol(B1, Decl(objectSpreadScenarios.ts, 0, 27))
+>b : Symbol(b, Decl(objectSpreadScenarios.ts, 12, 14))
+
+a1 = override(a1, { a: false });
+>a1 : Symbol(a1, Decl(objectSpreadScenarios.ts, 11, 3))
+>override : Symbol(override, Decl(objectSpreadScenarios.ts, 1, 27))
+>a1 : Symbol(a1, Decl(objectSpreadScenarios.ts, 11, 3))
+>a : Symbol(a, Decl(objectSpreadScenarios.ts, 13, 19))
+
+let host = { u: a1, update };
+>host : Symbol(host, Decl(objectSpreadScenarios.ts, 14, 3))
+>u : Symbol(u, Decl(objectSpreadScenarios.ts, 14, 12))
+>a1 : Symbol(a1, Decl(objectSpreadScenarios.ts, 11, 3))
+>update : Symbol(update, Decl(objectSpreadScenarios.ts, 14, 19))
+
+host.update({ a: false });
+>host.update : Symbol(update, Decl(objectSpreadScenarios.ts, 14, 19))
+>host : Symbol(host, Decl(objectSpreadScenarios.ts, 14, 3))
+>update : Symbol(update, Decl(objectSpreadScenarios.ts, 14, 19))
+>a : Symbol(a, Decl(objectSpreadScenarios.ts, 15, 13))
+
+let mixed = mixin(a1, b1);
+>mixed : Symbol(mixed, Decl(objectSpreadScenarios.ts, 16, 3))
+>mixin : Symbol(mixin, Decl(objectSpreadScenarios.ts, 7, 1))
+>a1 : Symbol(a1, Decl(objectSpreadScenarios.ts, 11, 3))
+>b1 : Symbol(b1, Decl(objectSpreadScenarios.ts, 12, 3))
+
diff --git a/tests/baselines/reference/objectSpreadScenarios.types b/tests/baselines/reference/objectSpreadScenarios.types
new file mode 100644
index 0000000000000..eebe08a2aafe7
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadScenarios.types
@@ -0,0 +1,106 @@
+=== tests/cases/conformance/types/spread/objectSpreadScenarios.ts ===
+interface A1 { a: boolean }
+>A1 : A1
+>a : boolean
+
+interface B1 { b: number };
+>B1 : B1
+>b : number
+
+function override<U>(initial: U, override: U): U {
+>override : <U>(initial: U, override: U) => U
+>U : U
+>initial : U
+>U : U
+>override : U
+>U : U
+>U : U
+
+    return { ...initial, ...override };
+>{ ...initial, ...override } : { ...U; ...U }
+>initial : any
+>override : any
+}
+function update<U>(this: { u: U }, override: U): void {
+>update : <U>(this: { u: U; }, override: U) => void
+>U : U
+>this : { u: U; }
+>u : U
+>U : U
+>override : U
+>U : U
+
+    this.u = { ...this.u, ...override };
+>this.u = { ...this.u, ...override } : { ...U; ...U }
+>this.u : U
+>this : { u: U; }
+>u : U
+>{ ...this.u, ...override } : { ...U; ...U }
+>this.u : U
+>this : { u: U; }
+>u : U
+>override : any
+}
+function mixin<T, U>(one: T, two: U): { ...T, ...U } {
+>mixin : <T, U>(one: T, two: U) => { ...T; ...U }
+>T : T
+>U : U
+>one : T
+>T : T
+>two : U
+>U : U
+>T : T
+>U : U
+
+    return { ...one, ...two };
+>{ ...one, ...two } : { ...T; ...U }
+>one : any
+>two : any
+}
+let a1: A1 = { a: true };
+>a1 : A1
+>A1 : A1
+>{ a: true } : { a: true; }
+>a : boolean
+>true : true
+
+let b1: B1 = { b: 101 };
+>b1 : B1
+>B1 : B1
+>{ b: 101 } : { b: number; }
+>b : number
+>101 : 101
+
+a1 = override(a1, { a: false });
+>a1 = override(a1, { a: false }) : A1
+>a1 : A1
+>override(a1, { a: false }) : A1
+>override : <U>(initial: U, override: U) => U
+>a1 : A1
+>{ a: false } : { a: false; }
+>a : boolean
+>false : false
+
+let host = { u: a1, update };
+>host : { u: A1; update: <U>(this: { u: U; }, override: U) => void; }
+>{ u: a1, update } : { u: A1; update: <U>(this: { u: U; }, override: U) => void; }
+>u : A1
+>a1 : A1
+>update : <U>(this: { u: U; }, override: U) => void
+
+host.update({ a: false });
+>host.update({ a: false }) : void
+>host.update : <U>(this: { u: U; }, override: U) => void
+>host : { u: A1; update: <U>(this: { u: U; }, override: U) => void; }
+>update : <U>(this: { u: U; }, override: U) => void
+>{ a: false } : { a: false; }
+>a : boolean
+>false : false
+
+let mixed = mixin(a1, b1);
+>mixed : { ...A1; ...B1 }
+>mixin(a1, b1) : { ...A1; ...B1 }
+>mixin : <T, U>(one: T, two: U) => { ...T; ...U }
+>a1 : A1
+>b1 : B1
+
diff --git a/tests/cases/conformance/types/spread/objectSpreadScenarios.ts b/tests/cases/conformance/types/spread/objectSpreadScenarios.ts
new file mode 100644
index 0000000000000..2f944ddb7966e
--- /dev/null
+++ b/tests/cases/conformance/types/spread/objectSpreadScenarios.ts
@@ -0,0 +1,17 @@
+interface A1 { a: boolean }
+interface B1 { b: number };
+function override<U>(initial: U, override: U): U {
+    return { ...initial, ...override };
+}
+function update<U>(this: { u: U }, override: U): void {
+    this.u = { ...this.u, ...override };
+}
+function mixin<T, U>(one: T, two: U): { ...T, ...U } {
+    return { ...one, ...two };
+}
+let a1: A1 = { a: true };
+let b1: B1 = { b: 101 };
+a1 = override(a1, { a: false });
+let host = { u: a1, update };
+host.update({ a: false });
+let mixed = mixin(a1, b1);

From 62c5bda3bbc1ee06d6ed0a575274da3159004f52 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 28 Sep 2016 14:14:53 -0700
Subject: [PATCH 016/224] isDeclaredProperty: Use optional-boolean idiom

As elsewhere in the compiler code
---
 src/compiler/types.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 0e120bd74f062..7a98efd007f8f 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2536,7 +2536,7 @@ namespace ts {
 
     /* @internal */
     export interface SpreadElementType extends ResolvedType {
-        isDeclaredProperty: boolean | undefined;
+        isDeclaredProperty?: boolean;
     }
 
     /* @internal */

From b9af986df1d4e277af6464033be98fbc666642d9 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 3 Oct 2016 15:18:04 -0700
Subject: [PATCH 017/224] Update object spread scenarios test

---
 tests/baselines/reference/objectSpreadScenarios.js    |  2 +-
 .../baselines/reference/objectSpreadScenarios.symbols |  3 ++-
 tests/baselines/reference/objectSpreadScenarios.types | 11 ++++++-----
 .../conformance/types/spread/objectSpreadScenarios.ts |  2 +-
 4 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/tests/baselines/reference/objectSpreadScenarios.js b/tests/baselines/reference/objectSpreadScenarios.js
index ae0e2f6c425ef..64739a2b298b0 100644
--- a/tests/baselines/reference/objectSpreadScenarios.js
+++ b/tests/baselines/reference/objectSpreadScenarios.js
@@ -1,7 +1,7 @@
 //// [objectSpreadScenarios.ts]
 interface A1 { a: boolean }
 interface B1 { b: number };
-function override<U>(initial: U, override: U): U {
+function override<U>(initial: U, override: U): { ...U, ...U } {
     return { ...initial, ...override };
 }
 function update<U>(this: { u: U }, override: U): void {
diff --git a/tests/baselines/reference/objectSpreadScenarios.symbols b/tests/baselines/reference/objectSpreadScenarios.symbols
index c8c18ca1e2f5b..784e340a10ce2 100644
--- a/tests/baselines/reference/objectSpreadScenarios.symbols
+++ b/tests/baselines/reference/objectSpreadScenarios.symbols
@@ -7,13 +7,14 @@ interface B1 { b: number };
 >B1 : Symbol(B1, Decl(objectSpreadScenarios.ts, 0, 27))
 >b : Symbol(B1.b, Decl(objectSpreadScenarios.ts, 1, 14))
 
-function override<U>(initial: U, override: U): U {
+function override<U>(initial: U, override: U): { ...U, ...U } {
 >override : Symbol(override, Decl(objectSpreadScenarios.ts, 1, 27))
 >U : Symbol(U, Decl(objectSpreadScenarios.ts, 2, 18))
 >initial : Symbol(initial, Decl(objectSpreadScenarios.ts, 2, 21))
 >U : Symbol(U, Decl(objectSpreadScenarios.ts, 2, 18))
 >override : Symbol(override, Decl(objectSpreadScenarios.ts, 2, 32))
 >U : Symbol(U, Decl(objectSpreadScenarios.ts, 2, 18))
+>U : Symbol(U, Decl(objectSpreadScenarios.ts, 2, 18))
 >U : Symbol(U, Decl(objectSpreadScenarios.ts, 2, 18))
 
     return { ...initial, ...override };
diff --git a/tests/baselines/reference/objectSpreadScenarios.types b/tests/baselines/reference/objectSpreadScenarios.types
index eebe08a2aafe7..5330029afe127 100644
--- a/tests/baselines/reference/objectSpreadScenarios.types
+++ b/tests/baselines/reference/objectSpreadScenarios.types
@@ -7,13 +7,14 @@ interface B1 { b: number };
 >B1 : B1
 >b : number
 
-function override<U>(initial: U, override: U): U {
->override : <U>(initial: U, override: U) => U
+function override<U>(initial: U, override: U): { ...U, ...U } {
+>override : <U>(initial: U, override: U) => { ...U; ...U }
 >U : U
 >initial : U
 >U : U
 >override : U
 >U : U
+>U : U
 >U : U
 
     return { ...initial, ...override };
@@ -72,10 +73,10 @@ let b1: B1 = { b: 101 };
 >101 : 101
 
 a1 = override(a1, { a: false });
->a1 = override(a1, { a: false }) : A1
+>a1 = override(a1, { a: false }) : { ...A1; ...A1 }
 >a1 : A1
->override(a1, { a: false }) : A1
->override : <U>(initial: U, override: U) => U
+>override(a1, { a: false }) : { ...A1; ...A1 }
+>override : <U>(initial: U, override: U) => { ...U; ...U }
 >a1 : A1
 >{ a: false } : { a: false; }
 >a : boolean
diff --git a/tests/cases/conformance/types/spread/objectSpreadScenarios.ts b/tests/cases/conformance/types/spread/objectSpreadScenarios.ts
index 2f944ddb7966e..c80cffa44e701 100644
--- a/tests/cases/conformance/types/spread/objectSpreadScenarios.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadScenarios.ts
@@ -1,6 +1,6 @@
 interface A1 { a: boolean }
 interface B1 { b: number };
-function override<U>(initial: U, override: U): U {
+function override<U>(initial: U, override: U): { ...U, ...U } {
     return { ...initial, ...override };
 }
 function update<U>(this: { u: U }, override: U): void {

From 57850ecf1ae5cad2a81112b4152133a99c8b9837 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 3 Oct 2016 15:49:23 -0700
Subject: [PATCH 018/224] Add more generic assignability cases

---
 .../cases/conformance/types/spread/objectSpreadGeneric.ts  | 7 +++++++
 .../cases/conformance/types/spread/objectSpreadNegative.ts | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/tests/cases/conformance/types/spread/objectSpreadGeneric.ts b/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
index 552142004b70f..a6919ce814931 100644
--- a/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
@@ -1,5 +1,12 @@
 function f<T, U, V>(t: T, u: U, v: V): void {
     let o: { ...T, ...U, ...V };
+    let uu: { ...U, ...U};
+    let u: { ...U };
+    let u0: U;
+    uu = u; // ok, multiple spreads are equivalent to a single one
+    u = uu; // ok, multiple spreads are equivalent to a single one
+    u0 = u; // error, might be missing a ton of stuff
+    u = u0; // ok, type has at least all the properties of the spread
     const same: { ...T, ...U, ...V } = o; // ok
     const reversed: { ...V, ...U, ...T } = o; // error, reversed
     const reversed2: { ...U, ...T, ...V } = o; // error, U and T are still reversed
diff --git a/tests/cases/conformance/types/spread/objectSpreadNegative.ts b/tests/cases/conformance/types/spread/objectSpreadNegative.ts
index 4691e45a17df3..4d1cfbe398c32 100644
--- a/tests/cases/conformance/types/spread/objectSpreadNegative.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadNegative.ts
@@ -47,3 +47,8 @@ callableConstructableSpread(12); // error, no call signature
 new callableConstructableSpread(12); // error, no construct signature
 
 let callableSpread = { ...publicx, ...(n => n + 1) }; // error, can't spread functions
+
+// { ...U } is not assignable to U
+function override<U>(initial: U, override: U): U {
+    return { ...initial, ...override };
+}

From 8421f735322e88f67b4b17feb2720e54c61639ea Mon Sep 17 00:00:00 2001
From: Ron Buckton <rbuckton@microsoft.com>
Date: Wed, 5 Oct 2016 17:20:42 -0700
Subject: [PATCH 019/224] Report missing global diagnostics

---
 src/compiler/checker.ts | 172 +++++++++++++++++++++++++++++++++-------
 src/compiler/core.ts    |  33 +++++++-
 2 files changed, 173 insertions(+), 32 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index ef428f26de913..9840df7d805f8 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5787,6 +5787,90 @@ namespace ts {
             }
         }
 
+        function getStaticTypeFromTypeNode(node: TypeNode) {
+            switch (node.kind) {
+                case SyntaxKind.AnyKeyword:
+                case SyntaxKind.JSDocAllType:
+                case SyntaxKind.JSDocUnknownType:
+                    return anyType;
+                case SyntaxKind.StringKeyword:
+                    return stringType;
+                case SyntaxKind.NumberKeyword:
+                    return numberType;
+                case SyntaxKind.BooleanKeyword:
+                    return booleanType;
+                case SyntaxKind.SymbolKeyword:
+                    return esSymbolType;
+                case SyntaxKind.VoidKeyword:
+                    return voidType;
+                case SyntaxKind.UndefinedKeyword:
+                    return undefinedType;
+                case SyntaxKind.NullKeyword:
+                    return nullType;
+                case SyntaxKind.NeverKeyword:
+                    return neverType;
+                case SyntaxKind.JSDocNullKeyword:
+                    return nullType;
+                case SyntaxKind.JSDocUndefinedKeyword:
+                    return undefinedType;
+                case SyntaxKind.JSDocNeverKeyword:
+                    return neverType;
+                case SyntaxKind.ThisType:
+                case SyntaxKind.ThisKeyword:
+                    return getTypeFromThisTypeNode(node);
+                case SyntaxKind.LiteralType:
+                    return getTypeFromLiteralTypeNode(<LiteralTypeNode>node);
+                case SyntaxKind.JSDocLiteralType:
+                    return getTypeFromLiteralTypeNode((<JSDocLiteralType>node).literal);
+                case SyntaxKind.TypeReference:
+                case SyntaxKind.JSDocTypeReference:
+                    return getTypeFromTypeReference(<TypeReferenceNode>node);
+                case SyntaxKind.TypePredicate:
+                    return booleanType;
+                case SyntaxKind.ExpressionWithTypeArguments:
+                    return getTypeFromTypeReference(<ExpressionWithTypeArguments>node);
+                case SyntaxKind.TypeQuery:
+                    return getTypeFromTypeQueryNode(<TypeQueryNode>node);
+                case SyntaxKind.ArrayType:
+                case SyntaxKind.JSDocArrayType:
+                    return getTypeFromArrayTypeNode(<ArrayTypeNode>node);
+                case SyntaxKind.TupleType:
+                    return getTypeFromTupleTypeNode(<TupleTypeNode>node);
+                case SyntaxKind.UnionType:
+                case SyntaxKind.JSDocUnionType:
+                    return getTypeFromUnionTypeNode(<UnionTypeNode>node, aliasSymbol, aliasTypeArguments);
+                case SyntaxKind.IntersectionType:
+                    return getTypeFromIntersectionTypeNode(<IntersectionTypeNode>node, aliasSymbol, aliasTypeArguments);
+                case SyntaxKind.ParenthesizedType:
+                case SyntaxKind.JSDocNullableType:
+                case SyntaxKind.JSDocNonNullableType:
+                case SyntaxKind.JSDocConstructorType:
+                case SyntaxKind.JSDocThisType:
+                case SyntaxKind.JSDocOptionalType:
+                    return getTypeFromTypeNode((<ParenthesizedTypeNode | JSDocTypeReferencingNode>node).type);
+                case SyntaxKind.JSDocRecordType:
+                    return getTypeFromTypeNode((node as JSDocRecordType).literal);
+                case SyntaxKind.FunctionType:
+                case SyntaxKind.ConstructorType:
+                case SyntaxKind.TypeLiteral:
+                case SyntaxKind.JSDocTypeLiteral:
+                case SyntaxKind.JSDocFunctionType:
+                    return getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node, aliasSymbol, aliasTypeArguments);
+                // This function assumes that an identifier or qualified name is a type expression
+                // Callers should first ensure this by calling isTypeNode
+                case SyntaxKind.Identifier:
+                case SyntaxKind.QualifiedName:
+                    const symbol = getSymbolAtLocation(node);
+                    return symbol && getDeclaredTypeOfSymbol(symbol);
+                case SyntaxKind.JSDocTupleType:
+                    return getTypeFromJSDocTupleType(<JSDocTupleType>node);
+                case SyntaxKind.JSDocVariadicType:
+                    return getTypeFromJSDocVariadicType(<JSDocVariadicType>node);
+                default:
+                    return unknownType;
+            }
+        }
+
         function instantiateList<T>(items: T[], mapper: TypeMapper, instantiator: (item: T, mapper: TypeMapper) => T): T[] {
             if (items && items.length) {
                 const result: T[] = [];
@@ -15181,31 +15265,24 @@ namespace ts {
         }
 
         /**
-          * Checks the return type of an async function to ensure it is a compatible
-          * Promise implementation.
-          * @param node The signature to check
-          * @param returnType The return type for the function
-          * @remarks
-          * This checks that an async function has a valid Promise-compatible return type,
-          * and returns the *awaited type* of the promise. An async function has a valid
-          * Promise-compatible return type if the resolved value of the return type has a
-          * construct signature that takes in an `initializer` function that in turn supplies
-          * a `resolve` function as one of its arguments and results in an object with a
-          * callable `then` signature.
-          */
+         * Checks the return type of an async function to ensure it is a compatible
+         * Promise implementation.
+         *
+         * This checks that an async function has a valid Promise-compatible return type,
+         * and returns the *awaited type* of the promise. An async function has a valid
+         * Promise-compatible return type if the resolved value of the return type has a
+         * construct signature that takes in an `initializer` function that in turn supplies
+         * a `resolve` function as one of its arguments and results in an object with a
+         * callable `then` signature.
+         *
+         * @param node The signature to check
+         */
         function checkAsyncFunctionReturnType(node: FunctionLikeDeclaration): Type {
             if (languageVersion >= ScriptTarget.ES6) {
                 const returnType = getTypeFromTypeNode(node.type);
                 return checkCorrectPromiseType(returnType, node.type, Diagnostics.The_return_type_of_an_async_function_or_method_must_be_the_global_Promise_T_type);
             }
 
-            const globalPromiseConstructorLikeType = getGlobalPromiseConstructorLikeType();
-            if (globalPromiseConstructorLikeType === emptyObjectType) {
-                // If we couldn't resolve the global PromiseConstructorLike type we cannot verify
-                // compatibility with __awaiter.
-                return unknownType;
-            }
-
             // As part of our emit for an async function, we will need to emit the entity name of
             // the return type annotation as an expression. To meet the necessary runtime semantics
             // for __awaiter, we must also check that the type of the declaration (e.g. the static
@@ -15230,18 +15307,35 @@ namespace ts {
             //      then<U>(...): Promise<U>;
             //  }
             //
-            // When we get the type of the `Promise` symbol here, we get the type of the static
-            // side of the `Promise` class, which would be `{ new <T>(...): Promise<T> }`.
+
+            const promiseName = getEntityNameFromTypeNode(node.type);
+            const rootName = getFirstIdentifier(promiseName);
+
+            // Mark the root symbol as referenced.
+            getSymbolLinks(rootName.symbol).referenced = true;
 
             const promiseType = getTypeFromTypeNode(node.type);
             if (promiseType === unknownType && compilerOptions.isolatedModules) {
                 // If we are compiling with isolatedModules, we may not be able to resolve the
-                // type as a value. As such, we will just return unknownType;
+                // type as a value. As such, we will just return unknownType.
                 return unknownType;
             }
 
+            const promiseConstructorType = getStaticTypeFromTypeNode(node.type);
+
+            const globalPromiseConstructorLikeType = getGlobalPromiseConstructorLikeType();
+            if (globalPromiseConstructorLikeType === emptyObjectType) {
+                // If we couldn't resolve the global PromiseConstructorLike type we cannot verify
+                // compatibility with __awaiter.
+                error(node.type || node.name || node, Diagnostics.An_async_function_or_method_must_have_a_valid_awaitable_return_type);
+                return unknownType;
+            }
+
+            // When we get the type of the `Promise` symbol here, we get the type of the static
+            // side of the `Promise` class, which would be `{ new <T>(...): Promise<T> }`.
+
             const promiseConstructor = getNodeLinks(node.type).resolvedSymbol;
-            if (!promiseConstructor || !symbolIsValue(promiseConstructor)) {
+            if (!promiseConstructor) {
                 // try to fall back to global promise type.
                 const typeName = promiseConstructor
                     ? symbolToString(promiseConstructor)
@@ -15259,12 +15353,10 @@ namespace ts {
             }
 
             // Verify there is no local declaration that could collide with the promise constructor.
-            const promiseName = getEntityNameFromTypeNode(node.type);
-            const promiseNameOrNamespaceRoot = getFirstIdentifier(promiseName);
-            const rootSymbol = getSymbol(node.locals, promiseNameOrNamespaceRoot.text, SymbolFlags.Value);
+            const rootSymbol = getSymbol(node.locals, rootName.text, SymbolFlags.Value);
             if (rootSymbol) {
                 error(rootSymbol.valueDeclaration, Diagnostics.Duplicate_identifier_0_Compiler_uses_declaration_1_to_support_async_functions,
-                    promiseNameOrNamespaceRoot.text,
+                    rootName.text,
                     getFullyQualifiedName(promiseConstructor));
                 return unknownType;
             }
@@ -18086,9 +18178,33 @@ namespace ts {
         function getDiagnosticsWorker(sourceFile: SourceFile): Diagnostic[] {
             throwIfNonDiagnosticsProducing();
             if (sourceFile) {
+                // Some global diagnostics are deferred until they are needed and
+                // may not be reported in the firt call to getGlobalDiagnostics.
+                // We should catch these changes and report them.
+                const previousGlobalDiagnostics = diagnostics.getGlobalDiagnostics();
+                const previousGlobalDiagnosticsSize = previousGlobalDiagnostics.length;
+
                 checkSourceFile(sourceFile);
-                return diagnostics.getDiagnostics(sourceFile.fileName);
+
+                const semanticDiagnostics = diagnostics.getDiagnostics(sourceFile.fileName);
+                const currentGlobalDiagnostics = diagnostics.getGlobalDiagnostics();
+                if (currentGlobalDiagnostics !== previousGlobalDiagnostics) {
+                    // If the arrays are not the same reference, new diagnostics were added.
+                    const deferredGlobalDiagnostics = relativeComplement(previousGlobalDiagnostics, currentGlobalDiagnostics, compareDiagnostics);
+                    return concatenate(deferredGlobalDiagnostics, semanticDiagnostics);
+                }
+                else if (previousGlobalDiagnosticsSize === 0 && currentGlobalDiagnostics.length > 0) {
+                    // If the arrays are the same reference, but the length has changed, a single
+                    // new diagnostic was added as DiagnosticCollection attempts to reuse the
+                    // same array.
+                    return concatenate(currentGlobalDiagnostics, semanticDiagnostics);
+                }
+
+                return semanticDiagnostics;
             }
+
+            // Global diagnostics are always added when a file is not provided to
+            // getDiagnostics
             forEach(host.getSourceFiles(), checkSourceFile);
             return diagnostics.getDiagnostics();
         }
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index e63bcbf8474b4..439e56095664f 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -400,8 +400,8 @@ namespace ts {
     }
 
     export function concatenate<T>(array1: T[], array2: T[]): T[] {
-        if (!array2 || !array2.length) return array1;
-        if (!array1 || !array1.length) return array2;
+        if (isEmptyArray(array2)) return array1;
+        if (isEmptyArray(array1)) return array2;
         return [...array1, ...array2];
     }
 
@@ -443,6 +443,27 @@ namespace ts {
         return result || array;
     }
 
+    /**
+     * Gets the relative complement of `arrayA` with respect to `b`, returning the elements that
+     * are not present in `arrayA` but are present in `arrayB`. Assumes both arrays are sorted
+     * based on the provided comparer.
+     */
+    export function relativeComplement<T>(arrayA: T[] | undefined, arrayB: T[] | undefined, comparer: (x: T, y: T) => Comparison = compareValues, offsetA: number = 0, offsetB: number = 0): T[] | undefined {
+        if (!arrayB || !arrayA || arrayB.length === 0 || arrayA.length === 0) return arrayB;
+        const result: T[] = [];
+        outer: for (; offsetB < arrayB.length; offsetB++) {
+            inner: for (; offsetA < arrayA.length; offsetA++) {
+                switch (comparer(arrayB[offsetB], arrayA[offsetA])) {
+                    case Comparison.LessThan: break inner;
+                    case Comparison.EqualTo: continue outer;
+                    case Comparison.GreaterThan: continue inner;
+                }
+            }
+            result.push(arrayB[offsetB]);
+        }
+        return result;
+    }
+
     export function sum(array: any[], prop: string): number {
         let result = 0;
         for (const v of array) {
@@ -505,12 +526,12 @@ namespace ts {
      * @param array A sorted array whose first element must be no larger than number
      * @param number The value to be searched for in the array.
      */
-    export function binarySearch<T>(array: T[], value: T, comparer?: (v1: T, v2: T) => number): number {
+    export function binarySearch<T>(array: T[], value: T, comparer?: (v1: T, v2: T) => number, offset?: number): number {
         if (!array || array.length === 0) {
             return -1;
         }
 
-        let low = 0;
+        let low = offset || 0;
         let high = array.length - 1;
         comparer = comparer !== undefined
             ? comparer
@@ -829,6 +850,10 @@ namespace ts {
         return Array.isArray ? Array.isArray(value) : value instanceof Array;
     }
 
+    export function isEmptyArray(value: any[] | undefined): boolean {
+        return !value || !value.length;
+    }
+
     export function memoize<T>(callback: () => T): () => T {
         let value: T;
         return () => {

From 763e78dc066bc26e2e4caa08d600b702e1f2fd4f Mon Sep 17 00:00:00 2001
From: Ron Buckton <rbuckton@microsoft.com>
Date: Thu, 6 Oct 2016 10:33:44 -0700
Subject: [PATCH 020/224] Simplify async return type checking

---
 src/compiler/checker.ts                       | 209 +++++-------------
 src/compiler/diagnosticMessages.json          |   2 +-
 src/compiler/transformers/ts.ts               |  15 +-
 src/compiler/utilities.ts                     |  35 ++-
 .../asyncAliasReturnType_es5.errors.txt       |  10 +
 .../asyncAwaitIsolatedModules_es5.js          |   1 +
 .../asyncFunctionDeclaration15_es5.errors.txt |  24 +-
 7 files changed, 108 insertions(+), 188 deletions(-)
 create mode 100644 tests/baselines/reference/asyncAliasReturnType_es5.errors.txt

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 9840df7d805f8..da5bd3a659038 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5787,90 +5787,6 @@ namespace ts {
             }
         }
 
-        function getStaticTypeFromTypeNode(node: TypeNode) {
-            switch (node.kind) {
-                case SyntaxKind.AnyKeyword:
-                case SyntaxKind.JSDocAllType:
-                case SyntaxKind.JSDocUnknownType:
-                    return anyType;
-                case SyntaxKind.StringKeyword:
-                    return stringType;
-                case SyntaxKind.NumberKeyword:
-                    return numberType;
-                case SyntaxKind.BooleanKeyword:
-                    return booleanType;
-                case SyntaxKind.SymbolKeyword:
-                    return esSymbolType;
-                case SyntaxKind.VoidKeyword:
-                    return voidType;
-                case SyntaxKind.UndefinedKeyword:
-                    return undefinedType;
-                case SyntaxKind.NullKeyword:
-                    return nullType;
-                case SyntaxKind.NeverKeyword:
-                    return neverType;
-                case SyntaxKind.JSDocNullKeyword:
-                    return nullType;
-                case SyntaxKind.JSDocUndefinedKeyword:
-                    return undefinedType;
-                case SyntaxKind.JSDocNeverKeyword:
-                    return neverType;
-                case SyntaxKind.ThisType:
-                case SyntaxKind.ThisKeyword:
-                    return getTypeFromThisTypeNode(node);
-                case SyntaxKind.LiteralType:
-                    return getTypeFromLiteralTypeNode(<LiteralTypeNode>node);
-                case SyntaxKind.JSDocLiteralType:
-                    return getTypeFromLiteralTypeNode((<JSDocLiteralType>node).literal);
-                case SyntaxKind.TypeReference:
-                case SyntaxKind.JSDocTypeReference:
-                    return getTypeFromTypeReference(<TypeReferenceNode>node);
-                case SyntaxKind.TypePredicate:
-                    return booleanType;
-                case SyntaxKind.ExpressionWithTypeArguments:
-                    return getTypeFromTypeReference(<ExpressionWithTypeArguments>node);
-                case SyntaxKind.TypeQuery:
-                    return getTypeFromTypeQueryNode(<TypeQueryNode>node);
-                case SyntaxKind.ArrayType:
-                case SyntaxKind.JSDocArrayType:
-                    return getTypeFromArrayTypeNode(<ArrayTypeNode>node);
-                case SyntaxKind.TupleType:
-                    return getTypeFromTupleTypeNode(<TupleTypeNode>node);
-                case SyntaxKind.UnionType:
-                case SyntaxKind.JSDocUnionType:
-                    return getTypeFromUnionTypeNode(<UnionTypeNode>node, aliasSymbol, aliasTypeArguments);
-                case SyntaxKind.IntersectionType:
-                    return getTypeFromIntersectionTypeNode(<IntersectionTypeNode>node, aliasSymbol, aliasTypeArguments);
-                case SyntaxKind.ParenthesizedType:
-                case SyntaxKind.JSDocNullableType:
-                case SyntaxKind.JSDocNonNullableType:
-                case SyntaxKind.JSDocConstructorType:
-                case SyntaxKind.JSDocThisType:
-                case SyntaxKind.JSDocOptionalType:
-                    return getTypeFromTypeNode((<ParenthesizedTypeNode | JSDocTypeReferencingNode>node).type);
-                case SyntaxKind.JSDocRecordType:
-                    return getTypeFromTypeNode((node as JSDocRecordType).literal);
-                case SyntaxKind.FunctionType:
-                case SyntaxKind.ConstructorType:
-                case SyntaxKind.TypeLiteral:
-                case SyntaxKind.JSDocTypeLiteral:
-                case SyntaxKind.JSDocFunctionType:
-                    return getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node, aliasSymbol, aliasTypeArguments);
-                // This function assumes that an identifier or qualified name is a type expression
-                // Callers should first ensure this by calling isTypeNode
-                case SyntaxKind.Identifier:
-                case SyntaxKind.QualifiedName:
-                    const symbol = getSymbolAtLocation(node);
-                    return symbol && getDeclaredTypeOfSymbol(symbol);
-                case SyntaxKind.JSDocTupleType:
-                    return getTypeFromJSDocTupleType(<JSDocTupleType>node);
-                case SyntaxKind.JSDocVariadicType:
-                    return getTypeFromJSDocVariadicType(<JSDocVariadicType>node);
-                default:
-                    return unknownType;
-            }
-        }
-
         function instantiateList<T>(items: T[], mapper: TypeMapper, instantiator: (item: T, mapper: TypeMapper) => T): T[] {
             if (items && items.length) {
                 const result: T[] = [];
@@ -15308,56 +15224,55 @@ namespace ts {
             //  }
             //
 
-            const promiseName = getEntityNameFromTypeNode(node.type);
-            const rootName = getFirstIdentifier(promiseName);
-
-            // Mark the root symbol as referenced.
-            getSymbolLinks(rootName.symbol).referenced = true;
+            // Always mark the type node as referenced if it points to a value
+            markTypeNodeAsReferenced(node.type);
 
+            const promiseConstructorName = getEntityNameFromTypeNode(node.type);
             const promiseType = getTypeFromTypeNode(node.type);
-            if (promiseType === unknownType && compilerOptions.isolatedModules) {
-                // If we are compiling with isolatedModules, we may not be able to resolve the
-                // type as a value. As such, we will just return unknownType.
+            if (promiseType === unknownType) {
+                if (!compilerOptions.isolatedModules) {
+                    if (promiseConstructorName) {
+                        error(node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, entityNameToString(promiseConstructorName));
+                    }
+                    else {
+                        error(node.type, Diagnostics.An_async_function_or_method_must_have_a_valid_awaitable_return_type);
+                    }
+                }
+                return unknownType;
+            }
+
+            if (promiseConstructorName === undefined) {
+                error(node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, typeToString(promiseType));
                 return unknownType;
             }
 
-            const promiseConstructorType = getStaticTypeFromTypeNode(node.type);
+            const promiseConstructorSymbol = resolveEntityName(promiseConstructorName, SymbolFlags.Value, /*ignoreErrors*/ true);
+            const promiseConstructorType = promiseConstructorSymbol ? getTypeOfSymbol(promiseConstructorSymbol) : unknownType;
+            if (promiseConstructorType === unknownType) {
+                error(node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, entityNameToString(promiseConstructorName));
+                return unknownType;
+            }
 
             const globalPromiseConstructorLikeType = getGlobalPromiseConstructorLikeType();
             if (globalPromiseConstructorLikeType === emptyObjectType) {
                 // If we couldn't resolve the global PromiseConstructorLike type we cannot verify
                 // compatibility with __awaiter.
-                error(node.type || node.name || node, Diagnostics.An_async_function_or_method_must_have_a_valid_awaitable_return_type);
+                error(node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, entityNameToString(promiseConstructorName));
                 return unknownType;
             }
 
-            // When we get the type of the `Promise` symbol here, we get the type of the static
-            // side of the `Promise` class, which would be `{ new <T>(...): Promise<T> }`.
-
-            const promiseConstructor = getNodeLinks(node.type).resolvedSymbol;
-            if (!promiseConstructor) {
-                // try to fall back to global promise type.
-                const typeName = promiseConstructor
-                    ? symbolToString(promiseConstructor)
-                    : typeToString(promiseType);
-                return checkCorrectPromiseType(promiseType, node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type, typeName);
-            }
-
-            // If the Promise constructor, resolved locally, is an alias symbol we should mark it as referenced.
-            checkReturnTypeAnnotationAsExpression(node);
-
-            // Validate the promise constructor type.
-            const promiseConstructorType = getTypeOfSymbol(promiseConstructor);
-            if (!checkTypeAssignableTo(promiseConstructorType, globalPromiseConstructorLikeType, node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type)) {
+            if (!checkTypeAssignableTo(promiseConstructorType, globalPromiseConstructorLikeType, node.type,
+                Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value)) {
                 return unknownType;
             }
 
             // Verify there is no local declaration that could collide with the promise constructor.
-            const rootSymbol = getSymbol(node.locals, rootName.text, SymbolFlags.Value);
-            if (rootSymbol) {
-                error(rootSymbol.valueDeclaration, Diagnostics.Duplicate_identifier_0_Compiler_uses_declaration_1_to_support_async_functions,
+            const rootName = promiseConstructorName && getFirstIdentifier(promiseConstructorName);
+            const collidingSymbol = getSymbol(node.locals, rootName.text, SymbolFlags.Value);
+            if (collidingSymbol) {
+                error(collidingSymbol.valueDeclaration, Diagnostics.Duplicate_identifier_0_Compiler_uses_declaration_1_to_support_async_functions,
                     rootName.text,
-                    getFullyQualifiedName(promiseConstructor));
+                    entityNameToString(promiseConstructorName));
                 return unknownType;
             }
 
@@ -15415,44 +15330,19 @@ namespace ts {
                 errorInfo);
         }
 
-        /** Checks a type reference node as an expression. */
-        function checkTypeNodeAsExpression(node: TypeNode) {
-            // When we are emitting type metadata for decorators, we need to try to check the type
-            // as if it were an expression so that we can emit the type in a value position when we
-            // serialize the type metadata.
-            if (node && node.kind === SyntaxKind.TypeReference) {
-                const root = getFirstIdentifier((<TypeReferenceNode>node).typeName);
-                const meaning = root.parent.kind === SyntaxKind.TypeReference ? SymbolFlags.Type : SymbolFlags.Namespace;
-                // Resolve type so we know which symbol is referenced
-                const rootSymbol = resolveName(root, root.text, meaning | SymbolFlags.Alias, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined);
-                // Resolved symbol is alias
-                if (rootSymbol && rootSymbol.flags & SymbolFlags.Alias) {
-                    const aliasTarget = resolveAlias(rootSymbol);
-                    // If alias has value symbol - mark alias as referenced
-                    if (aliasTarget.flags & SymbolFlags.Value && !isConstEnumOrConstEnumOnlyModule(resolveAlias(rootSymbol))) {
-                        markAliasSymbolAsReferenced(rootSymbol);
-                    }
-                }
-            }
-        }
-
         /**
-          * Checks the type annotation of an accessor declaration or property declaration as
-          * an expression if it is a type reference to a type with a value declaration.
-          */
-        function checkTypeAnnotationAsExpression(node: VariableLikeDeclaration) {
-            checkTypeNodeAsExpression((<PropertyDeclaration>node).type);
-        }
-
-        function checkReturnTypeAnnotationAsExpression(node: FunctionLikeDeclaration) {
-            checkTypeNodeAsExpression(node.type);
-        }
-
-        /** Checks the type annotation of the parameters of a function/method or the constructor of a class as expressions */
-        function checkParameterTypeAnnotationsAsExpressions(node: FunctionLikeDeclaration) {
-            // ensure all type annotations with a value declaration are checked as an expression
-            for (const parameter of node.parameters) {
-                checkTypeAnnotationAsExpression(parameter);
+         * If a TypeNode can be resolved to a value symbol imported from an external module, it is
+         * marked as referenced to prevent import elision.
+         */
+        function markTypeNodeAsReferenced(node: TypeNode) {
+            const typeName = node && getEntityNameFromTypeNode(node);
+            const rootName = typeName && getFirstIdentifier(typeName);
+            const rootSymbol = rootName && resolveName(rootName, rootName.text, (typeName.kind === SyntaxKind.Identifier ? SymbolFlags.Type : SymbolFlags.Namespace) | SymbolFlags.Alias, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined);
+            if (rootSymbol
+                && rootSymbol.flags & SymbolFlags.Alias
+                && symbolIsValue(rootSymbol)
+                && !isConstEnumOrConstEnumOnlyModule(resolveAlias(rootSymbol))) {
+                markAliasSymbolAsReferenced(rootSymbol);
             }
         }
 
@@ -15478,20 +15368,25 @@ namespace ts {
                     case SyntaxKind.ClassDeclaration:
                         const constructor = getFirstConstructorWithBody(<ClassDeclaration>node);
                         if (constructor) {
-                            checkParameterTypeAnnotationsAsExpressions(constructor);
+                            for (const parameter of constructor.parameters) {
+                                markTypeNodeAsReferenced(parameter.type);
+                            }
                         }
                         break;
 
                     case SyntaxKind.MethodDeclaration:
                     case SyntaxKind.GetAccessor:
                     case SyntaxKind.SetAccessor:
-                        checkParameterTypeAnnotationsAsExpressions(<FunctionLikeDeclaration>node);
-                        checkReturnTypeAnnotationAsExpression(<FunctionLikeDeclaration>node);
+                        for (const parameter of (<FunctionLikeDeclaration>node).parameters) {
+                            markTypeNodeAsReferenced(parameter.type);
+                        }
+
+                        markTypeNodeAsReferenced((<FunctionLikeDeclaration>node).type);
                         break;
 
                     case SyntaxKind.PropertyDeclaration:
                     case SyntaxKind.Parameter:
-                        checkTypeAnnotationAsExpression(<PropertyDeclaration | ParameterDeclaration>node);
+                        markTypeNodeAsReferenced((<PropertyDeclaration | ParameterDeclaration>node).type);
                         break;
                 }
             }
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 71d7a978d1ba0..815ca9a9d6773 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -163,7 +163,7 @@
         "category": "Error",
         "code": 1054
     },
-    "Type '{0}' is not a valid async function return type.": {
+    "Type '{0}' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.": {
         "category": "Error",
         "code": 1055
     },
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 2419ffa4c3b73..352d6f6f1dc8b 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -2329,15 +2329,16 @@ namespace ts {
         }
 
         function getPromiseConstructor(type: TypeNode) {
-            const typeName = getEntityNameFromTypeNode(type);
-            if (typeName && isEntityName(typeName)) {
-                const serializationKind = resolver.getTypeReferenceSerializationKind(typeName);
-                if (serializationKind === TypeReferenceSerializationKind.TypeWithConstructSignatureAndValue
-                    || serializationKind === TypeReferenceSerializationKind.Unknown) {
-                    return typeName;
+            if (type) {
+                const typeName = getEntityNameFromTypeNode(type);
+                if (typeName && isEntityName(typeName)) {
+                    const serializationKind = resolver.getTypeReferenceSerializationKind(typeName);
+                    if (serializationKind === TypeReferenceSerializationKind.TypeWithConstructSignatureAndValue
+                        || serializationKind === TypeReferenceSerializationKind.Unknown) {
+                        return typeName;
+                    }
                 }
             }
-
             return undefined;
         }
 
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 62813e9447c87..b6d81e3f242cf 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -503,6 +503,17 @@ namespace ts {
         return getFullWidth(name) === 0 ? "(Missing)" : getTextOfNode(name);
     }
 
+    export function entityNameToString(name: EntityNameOrEntityNameExpression): string {
+        switch (name.kind) {
+            case SyntaxKind.Identifier:
+                return getFullWidth(name) === 0 ? unescapeIdentifier((<Identifier>name).text) : getTextOfNode(name);
+            case SyntaxKind.QualifiedName:
+                return entityNameToString((<QualifiedName>name).left) + "." + entityNameToString((<QualifiedName>name).right);
+            case SyntaxKind.PropertyAccessExpression:
+                return entityNameToString((<PropertyAccessEntityNameExpression>name).expression) + "." + entityNameToString((<PropertyAccessEntityNameExpression>name).name);
+        }
+    }
+
     export function createDiagnosticForNode(node: Node, message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any): Diagnostic {
         const sourceFile = getSourceFileOfNode(node);
         const span = getErrorSpanForNode(sourceFile, node);
@@ -1054,17 +1065,19 @@ namespace ts {
     }
 
     export function getEntityNameFromTypeNode(node: TypeNode): EntityNameOrEntityNameExpression {
-        if (node) {
-            switch (node.kind) {
-                case SyntaxKind.TypeReference:
-                    return (<TypeReferenceNode>node).typeName;
-                case SyntaxKind.ExpressionWithTypeArguments:
-                    Debug.assert(isEntityNameExpression((<ExpressionWithTypeArguments>node).expression));
-                    return <EntityNameExpression>(<ExpressionWithTypeArguments>node).expression;
-                case SyntaxKind.Identifier:
-                case SyntaxKind.QualifiedName:
-                    return (<EntityName><Node>node);
-            }
+        switch (node.kind) {
+            case SyntaxKind.TypeReference:
+            case SyntaxKind.JSDocTypeReference:
+                return (<TypeReferenceNode>node).typeName;
+
+            case SyntaxKind.ExpressionWithTypeArguments:
+                return isEntityNameExpression((<ExpressionWithTypeArguments>node).expression)
+                    ? <EntityNameExpression>(<ExpressionWithTypeArguments>node).expression
+                    : undefined;
+
+            case SyntaxKind.Identifier:
+            case SyntaxKind.QualifiedName:
+                return (<EntityName><Node>node);
         }
 
         return undefined;
diff --git a/tests/baselines/reference/asyncAliasReturnType_es5.errors.txt b/tests/baselines/reference/asyncAliasReturnType_es5.errors.txt
new file mode 100644
index 0000000000000..5e524e265e229
--- /dev/null
+++ b/tests/baselines/reference/asyncAliasReturnType_es5.errors.txt
@@ -0,0 +1,10 @@
+tests/cases/conformance/async/es5/asyncAliasReturnType_es5.ts(3,21): error TS1055: Type 'PromiseAlias' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+
+
+==== tests/cases/conformance/async/es5/asyncAliasReturnType_es5.ts (1 errors) ====
+    type PromiseAlias<T> = Promise<T>;
+    
+    async function f(): PromiseAlias<void> {
+                        ~~~~~~~~~~~~~~~~~~
+!!! error TS1055: Type 'PromiseAlias' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/asyncAwaitIsolatedModules_es5.js b/tests/baselines/reference/asyncAwaitIsolatedModules_es5.js
index 7eb2157c02663..d1d1db3e32979 100644
--- a/tests/baselines/reference/asyncAwaitIsolatedModules_es5.js
+++ b/tests/baselines/reference/asyncAwaitIsolatedModules_es5.js
@@ -77,6 +77,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var _this = this;
+var missing_1 = require("missing");
 function f0() {
     return __awaiter(this, void 0, void 0, function () { return __generator(this, function (_a) {
         return [2 /*return*/];
diff --git a/tests/baselines/reference/asyncFunctionDeclaration15_es5.errors.txt b/tests/baselines/reference/asyncFunctionDeclaration15_es5.errors.txt
index 3ea03927aa9ba..5fa332339124a 100644
--- a/tests/baselines/reference/asyncFunctionDeclaration15_es5.errors.txt
+++ b/tests/baselines/reference/asyncFunctionDeclaration15_es5.errors.txt
@@ -1,9 +1,9 @@
-tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(6,23): error TS1055: Type '{}' is not a valid async function return type.
-tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(7,23): error TS1055: Type 'any' is not a valid async function return type.
-tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(8,23): error TS1055: Type 'number' is not a valid async function return type.
-tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(9,23): error TS1055: Type 'PromiseLike' is not a valid async function return type.
-tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(10,23): error TS1055: Type 'typeof Thenable' is not a valid async function return type.
-tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(10,23): error TS1055: Type 'typeof Thenable' is not a valid async function return type.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(6,23): error TS1055: Type '{}' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(7,23): error TS1055: Type 'any' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(8,23): error TS1055: Type 'number' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(9,23): error TS1055: Type 'PromiseLike' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(10,23): error TS1055: Type 'typeof Thenable' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(10,23): error TS1055: Type 'typeof Thenable' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
   Type 'Thenable' is not assignable to type 'PromiseLike<any>'.
     Types of property 'then' are incompatible.
       Type '() => void' is not assignable to type '{ (onfulfilled?: (value: any) => any, onrejected?: (reason: any) => any): PromiseLike<any>; <TResult>(onfulfilled: (value: any) => any, onrejected: (reason: any) => TResult | PromiseLike<TResult>): PromiseLike<any>; <TResult>(onfulfilled: (value: any) => TResult | PromiseLike<TResult>, onrejected?: (reason: any) => TResult | PromiseLike<TResult>): PromiseLike<TResult>; <TResult1, TResult2>(onfulfilled: (value: any) => TResult1 | PromiseLike<TResult1>, onrejected: (reason: any) => TResult2 | PromiseLike<TResult2>): PromiseLike<TResult1 | TResult2>; }'.
@@ -20,21 +20,21 @@ tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration1
     async function fn1() { } // valid: Promise<void>
     async function fn2(): { } { } // error
                           ~~~
-!!! error TS1055: Type '{}' is not a valid async function return type.
+!!! error TS1055: Type '{}' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
     async function fn3(): any { } // error
                           ~~~
-!!! error TS1055: Type 'any' is not a valid async function return type.
+!!! error TS1055: Type 'any' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
     async function fn4(): number { } // error
                           ~~~~~~
-!!! error TS1055: Type 'number' is not a valid async function return type.
+!!! error TS1055: Type 'number' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
     async function fn5(): PromiseLike<void> { } // error
                           ~~~~~~~~~~~~~~~~~
-!!! error TS1055: Type 'PromiseLike' is not a valid async function return type.
+!!! error TS1055: Type 'PromiseLike' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
     async function fn6(): Thenable { } // error
                           ~~~~~~~~
-!!! error TS1055: Type 'typeof Thenable' is not a valid async function return type.
+!!! error TS1055: Type 'typeof Thenable' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
                           ~~~~~~~~
-!!! error TS1055: Type 'typeof Thenable' is not a valid async function return type.
+!!! error TS1055: Type 'typeof Thenable' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
 !!! error TS1055:   Type 'Thenable' is not assignable to type 'PromiseLike<any>'.
 !!! error TS1055:     Types of property 'then' are incompatible.
 !!! error TS1055:       Type '() => void' is not assignable to type '{ (onfulfilled?: (value: any) => any, onrejected?: (reason: any) => any): PromiseLike<any>; <TResult>(onfulfilled: (value: any) => any, onrejected: (reason: any) => TResult | PromiseLike<TResult>): PromiseLike<any>; <TResult>(onfulfilled: (value: any) => TResult | PromiseLike<TResult>, onrejected?: (reason: any) => TResult | PromiseLike<TResult>): PromiseLike<TResult>; <TResult1, TResult2>(onfulfilled: (value: any) => TResult1 | PromiseLike<TResult1>, onrejected: (reason: any) => TResult2 | PromiseLike<TResult2>): PromiseLike<TResult1 | TResult2>; }'.

From aadcbcc083d984f266cfb6188c5dc4dd2cd908fa Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Mon, 26 Sep 2016 11:33:25 -0700
Subject: [PATCH 021/224] Use native maps when they're available

---
 Jakefile.js                                   |   2 +
 scripts/processDiagnosticMessages.ts          |  18 +-
 src/compiler/binder.ts                        |  44 +-
 src/compiler/checker.ts                       | 480 +++++++-------
 src/compiler/commandLineParser.ts             | 130 ++--
 src/compiler/core.ts                          | 287 +-------
 src/compiler/dataStructures.ts                | 624 ++++++++++++++++++
 src/compiler/declarationEmitter.ts            |  18 +-
 src/compiler/emitter.ts                       |  18 +-
 src/compiler/factory.ts                       |  18 +-
 src/compiler/parser.ts                        |   6 +-
 src/compiler/performance.ts                   |  30 +-
 src/compiler/program.ts                       |  72 +-
 src/compiler/scanner.ts                       |  21 +-
 src/compiler/sourcemap.ts                     |   2 +-
 src/compiler/sys.ts                           |  21 +-
 src/compiler/transformer.ts                   |  20 +-
 src/compiler/transformers/es6.ts              |  31 +-
 src/compiler/transformers/generators.ts       |  32 +-
 src/compiler/transformers/jsx.ts              |   8 +-
 src/compiler/transformers/module/module.ts    |  48 +-
 src/compiler/transformers/module/system.ts    |  12 +-
 src/compiler/transformers/ts.ts               |  20 +-
 src/compiler/tsc.ts                           |  34 +-
 src/compiler/tsconfig.json                    |   1 +
 src/compiler/types.ts                         |  69 +-
 src/compiler/utilities.ts                     |  56 +-
 src/compiler/visitor.ts                       |  54 +-
 src/harness/fourslash.ts                      |  46 +-
 src/harness/harness.ts                        |  27 +-
 src/harness/harnessLanguageService.ts         |   4 +-
 src/harness/loggedIO.ts                       |  10 +-
 src/harness/projectsRunner.ts                 |  21 +-
 .../unittests/cachingInServerLSHost.ts        |  23 +-
 src/harness/unittests/moduleResolution.ts     |  64 +-
 .../unittests/reuseProgramStructure.ts        |  27 +-
 src/harness/unittests/session.ts              |  22 +-
 .../unittests/tsserverProjectSystem.ts        |  39 +-
 src/server/builder.ts                         |  15 +-
 src/server/client.ts                          |   8 +-
 src/server/editorServices.ts                  |  57 +-
 src/server/lsHost.ts                          |  20 +-
 src/server/project.ts                         |  51 +-
 src/server/scriptInfo.ts                      |   4 +-
 src/server/session.ts                         |  10 +-
 src/server/tsconfig.library.json              |   2 +-
 src/server/typingsCache.ts                    |  27 +-
 .../typingsInstaller/typingsInstaller.ts      |  42 +-
 src/server/utilities.ts                       |  43 +-
 src/services/classifier.ts                    |   6 +-
 src/services/completions.ts                   |  55 +-
 src/services/documentHighlights.ts            |   6 +-
 src/services/documentRegistry.ts              |  39 +-
 src/services/findAllReferences.ts             |  31 +-
 src/services/formatting/rules.ts              |   2 +-
 src/services/goToDefinition.ts                |   2 +-
 src/services/jsTyping.ts                      |  45 +-
 src/services/navigateTo.ts                    |  19 +-
 src/services/navigationBar.ts                 |   8 +-
 src/services/patternMatcher.ts                |   8 +-
 src/services/services.ts                      |  28 +-
 src/services/shims.ts                         |   2 +-
 src/services/signatureHelp.ts                 |   2 +-
 src/services/transpile.ts                     |   6 +-
 src/services/types.ts                         |   4 +-
 tslint.json                                   |   3 +-
 66 files changed, 1678 insertions(+), 1326 deletions(-)
 create mode 100644 src/compiler/dataStructures.ts

diff --git a/Jakefile.js b/Jakefile.js
index 64a8553ef39dc..2e4a30c90c61a 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -57,6 +57,7 @@ function measure(marker) {
 }
 
 var compilerSources = [
+    "dataStructures.ts",
     "core.ts",
     "performance.ts",
     "sys.ts",
@@ -91,6 +92,7 @@ var compilerSources = [
 });
 
 var servicesSources = [
+    "dataStructures.ts",
     "core.ts",
     "performance.ts",
     "sys.ts",
diff --git a/scripts/processDiagnosticMessages.ts b/scripts/processDiagnosticMessages.ts
index e5eaa46c8e5b9..d6133e6dab0a5 100644
--- a/scripts/processDiagnosticMessages.ts
+++ b/scripts/processDiagnosticMessages.ts
@@ -27,7 +27,7 @@ function main(): void {
 
     var inputFilePath = sys.args[0].replace(/\\/g, "/");
     var inputStr = sys.readFile(inputFilePath);
-    
+
     var diagnosticMessages: InputDiagnosticMessageTable = JSON.parse(inputStr);
 
     var names = Utilities.getObjectKeys(diagnosticMessages);
@@ -44,7 +44,7 @@ function main(): void {
 function checkForUniqueCodes(messages: string[], diagnosticTable: InputDiagnosticMessageTable) {
     const originalMessageForCode: string[] = [];
     let numConflicts = 0;
-    
+
     for (const currentMessage of messages) {
         const code = diagnosticTable[currentMessage].code;
 
@@ -68,19 +68,19 @@ function checkForUniqueCodes(messages: string[], diagnosticTable: InputDiagnosti
     }
 }
 
-function buildUniqueNameMap(names: string[]): ts.Map<string> {
-    var nameMap = ts.createMap<string>();
+function buildUniqueNameMap(names: string[]): ts.Map<string, string> {
+    var nameMap = new ts.StringMap<string>();
 
     var uniqueNames = NameGenerator.ensureUniqueness(names, /* isCaseSensitive */ false, /* isFixed */ undefined);
 
     for (var i = 0; i < names.length; i++) {
-        nameMap[names[i]] = uniqueNames[i];
+        nameMap.set(names[i], uniqueNames[i]);
     }
 
     return nameMap;
 }
 
-function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable, nameMap: ts.Map<string>): string {
+function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable, nameMap: ts.Map<string, string>): string {
     var result =
         '// <auto-generated />\r\n' +
         '/// <reference path="types.ts" />\r\n' +
@@ -91,7 +91,7 @@ function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable, nameMap:
     for (var i = 0; i < names.length; i++) {
         var name = names[i];
         var diagnosticDetails = messageTable[name];
-        var propName = convertPropertyName(nameMap[name]);
+        var propName = convertPropertyName(nameMap.get(name));
 
         result +=
         '        ' + propName +
@@ -107,14 +107,14 @@ function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable, nameMap:
     return result;
 }
 
-function buildDiagnosticMessageOutput(messageTable: InputDiagnosticMessageTable, nameMap: ts.Map<string>): string {
+function buildDiagnosticMessageOutput(messageTable: InputDiagnosticMessageTable, nameMap: ts.Map<string, string>): string {
     var result =
         '{';
     var names = Utilities.getObjectKeys(messageTable);
     for (var i = 0; i < names.length; i++) {
         var name = names[i];
         var diagnosticDetails = messageTable[name];
-        var propName = convertPropertyName(nameMap[name]);
+        var propName = convertPropertyName(nameMap.get(name));
 
         result += '\r\n  "' + createKey(propName, diagnosticDetails.code) + '"' + ' : "' + name.replace(/[\"]/g, '\\"') + '"';
         if (i !== names.length - 1) {
diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 04b115b4dd9dd..deee2061005c0 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -126,7 +126,7 @@ namespace ts {
 
         let symbolCount = 0;
         let Symbol: { new (flags: SymbolFlags, name: string): Symbol };
-        let classifiableNames: Map<string>;
+        let classifiableNames: Set<string>;
 
         const unreachableFlow: FlowNode = { flags: FlowFlags.Unreachable };
         const reportedUnreachableFlow: FlowNode = { flags: FlowFlags.Unreachable };
@@ -140,7 +140,7 @@ namespace ts {
             options = opts;
             languageVersion = getEmitScriptTarget(options);
             inStrictMode = !!file.externalModuleIndicator;
-            classifiableNames = createMap<string>();
+            classifiableNames = new StringSet();
             symbolCount = 0;
             skipTransformFlagAggregation = isDeclarationFile(file);
 
@@ -190,11 +190,11 @@ namespace ts {
             symbol.declarations.push(node);
 
             if (symbolFlags & SymbolFlags.HasExports && !symbol.exports) {
-                symbol.exports = createMap<Symbol>();
+                symbol.exports = new StringMap<Symbol>();
             }
 
             if (symbolFlags & SymbolFlags.HasMembers && !symbol.members) {
-                symbol.members = createMap<Symbol>();
+                symbol.members = new StringMap<Symbol>();
             }
 
             if (symbolFlags & SymbolFlags.Value) {
@@ -332,17 +332,17 @@ namespace ts {
                 // Otherwise, we'll be merging into a compatible existing symbol (for example when
                 // you have multiple 'vars' with the same name in the same container).  In this case
                 // just add this node into the declarations list of the symbol.
-                symbol = symbolTable[name] || (symbolTable[name] = createSymbol(SymbolFlags.None, name));
+                symbol = getOrUpdate(symbolTable, name, name => createSymbol(SymbolFlags.None, name));
 
                 if (name && (includes & SymbolFlags.Classifiable)) {
-                    classifiableNames[name] = name;
+                    classifiableNames.add(name);
                 }
 
                 if (symbol.flags & excludes) {
                     if (symbol.isReplaceableByMethod) {
                         // Javascript constructor-declared symbols can be discarded in favor of
                         // prototype symbols like methods.
-                        symbol = symbolTable[name] = createSymbol(SymbolFlags.None, name);
+                        symbol = setAndReturn(symbolTable, name, createSymbol(SymbolFlags.None, name));
                     }
                     else {
                         if (node.name) {
@@ -450,7 +450,7 @@ namespace ts {
             if (containerFlags & ContainerFlags.IsContainer) {
                 container = blockScopeContainer = node;
                 if (containerFlags & ContainerFlags.HasLocals) {
-                    container.locals = createMap<Symbol>();
+                    container.locals = new StringMap<Symbol>();
                 }
                 addToContainerChain(container);
             }
@@ -1447,8 +1447,7 @@ namespace ts {
 
             const typeLiteralSymbol = createSymbol(SymbolFlags.TypeLiteral, "__type");
             addDeclarationToSymbol(typeLiteralSymbol, node, SymbolFlags.TypeLiteral);
-            typeLiteralSymbol.members = createMap<Symbol>();
-            typeLiteralSymbol.members[symbol.name] = symbol;
+            typeLiteralSymbol.members = createMapWithEntry(symbol.name, symbol);
         }
 
         function bindObjectLiteralExpression(node: ObjectLiteralExpression) {
@@ -1458,7 +1457,7 @@ namespace ts {
             }
 
             if (inStrictMode) {
-                const seen = createMap<ElementKind>();
+                const seen = new StringMap<ElementKind>();
 
                 for (const prop of node.properties) {
                     if (prop.name.kind !== SyntaxKind.Identifier) {
@@ -1479,9 +1478,9 @@ namespace ts {
                         ? ElementKind.Property
                         : ElementKind.Accessor;
 
-                    const existingKind = seen[identifier.text];
+                    const existingKind = seen.get(identifier.text);
                     if (!existingKind) {
-                        seen[identifier.text] = currentKind;
+                        seen.set(identifier.text, currentKind);
                         continue;
                     }
 
@@ -1514,7 +1513,7 @@ namespace ts {
                 // fall through.
                 default:
                     if (!blockScopeContainer.locals) {
-                        blockScopeContainer.locals = createMap<Symbol>();
+                        blockScopeContainer.locals = new StringMap<Symbol>();
                         addToContainerChain(blockScopeContainer);
                     }
                     declareSymbol(blockScopeContainer.locals, undefined, node, symbolFlags, symbolExcludes);
@@ -1976,7 +1975,7 @@ namespace ts {
                 }
             }
 
-            file.symbol.globalExports = file.symbol.globalExports || createMap<Symbol>();
+            file.symbol.globalExports = file.symbol.globalExports || new StringMap<Symbol>();
             declareSymbol(file.symbol.globalExports, file.symbol, node, SymbolFlags.Alias, SymbolFlags.AliasExcludes);
         }
 
@@ -2021,7 +2020,7 @@ namespace ts {
             Debug.assert(isInJavaScriptFile(node));
             // Declare a 'member' if the container is an ES5 class or ES6 constructor
             if (container.kind === SyntaxKind.FunctionDeclaration || container.kind === SyntaxKind.FunctionExpression) {
-                container.symbol.members = container.symbol.members || createMap<Symbol>();
+                container.symbol.members = container.symbol.members || new StringMap<Symbol>();
                 // It's acceptable for multiple 'this' assignments of the same identifier to occur
                 declareSymbol(container.symbol.members, container.symbol, node, SymbolFlags.Property, SymbolFlags.PropertyExcludes & ~SymbolFlags.Property);
             }
@@ -2053,14 +2052,14 @@ namespace ts {
             constructorFunction.parent = classPrototype;
             classPrototype.parent = leftSideOfAssignment;
 
-            const funcSymbol = container.locals[constructorFunction.text];
+            const funcSymbol = container.locals.get(constructorFunction.text);
             if (!funcSymbol || !(funcSymbol.flags & SymbolFlags.Function || isDeclarationOfFunctionExpression(funcSymbol))) {
                 return;
             }
 
             // Set up the members collection if it doesn't exist already
             if (!funcSymbol.members) {
-                funcSymbol.members = createMap<Symbol>();
+                funcSymbol.members = new StringMap<Symbol>();
             }
 
             // Declare the method/property
@@ -2093,7 +2092,7 @@ namespace ts {
                 bindAnonymousDeclaration(node, SymbolFlags.Class, bindingName);
                 // Add name of class expression into the map for semantic classifier
                 if (node.name) {
-                    classifiableNames[node.name.text] = node.name.text;
+                    classifiableNames.add(node.name.text);
                 }
             }
 
@@ -2109,14 +2108,15 @@ namespace ts {
             // module might have an exported variable called 'prototype'.  We can't allow that as
             // that would clash with the built-in 'prototype' for the class.
             const prototypeSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Prototype, "prototype");
-            if (symbol.exports[prototypeSymbol.name]) {
+            const symbolExport = symbol.exports.get(prototypeSymbol.name);
+            if (symbolExport) {
                 if (node.name) {
                     node.name.parent = node;
                 }
-                file.bindDiagnostics.push(createDiagnosticForNode(symbol.exports[prototypeSymbol.name].declarations[0],
+                file.bindDiagnostics.push(createDiagnosticForNode(symbolExport.declarations[0],
                     Diagnostics.Duplicate_identifier_0, prototypeSymbol.name));
             }
-            symbol.exports[prototypeSymbol.name] = prototypeSymbol;
+            symbol.exports.set(prototypeSymbol.name, prototypeSymbol);
             prototypeSymbol.parent = symbol;
         }
 
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 8fef558968e34..941bfdfac8bbd 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -47,7 +47,7 @@ namespace ts {
         let symbolCount = 0;
 
         const emptyArray: any[] = [];
-        const emptySymbols = createMap<Symbol>();
+        const emptySymbols = new StringMap<Symbol>();
 
         const compilerOptions = host.getCompilerOptions();
         const languageVersion = compilerOptions.target || ScriptTarget.ES3;
@@ -111,10 +111,10 @@ namespace ts {
         };
 
         const tupleTypes: GenericType[] = [];
-        const unionTypes = createMap<UnionType>();
-        const intersectionTypes = createMap<IntersectionType>();
-        const stringLiteralTypes = createMap<LiteralType>();
-        const numericLiteralTypes = createMap<LiteralType>();
+        const unionTypes = new StringMap<UnionType>();
+        const intersectionTypes = new StringMap<IntersectionType>();
+        const stringLiteralTypes = new StringMap<LiteralType>();
+        const numericLiteralTypes = new StringMap<LiteralType>();
 
         const unknownSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Transient, "unknown");
         const resolvingSymbol = createSymbol(SymbolFlags.Transient, "__resolving__");
@@ -137,7 +137,7 @@ namespace ts {
 
         const emptyObjectType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
         const emptyGenericType = <GenericType><ObjectType>createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
-        emptyGenericType.instantiations = createMap<TypeReference>();
+        emptyGenericType.instantiations = new StringMap<TypeReference>();
 
         const anyFunctionType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
         // The anyFunctionType contains the anyFunctionType by definition. The flag is further propagated
@@ -153,7 +153,7 @@ namespace ts {
 
         const enumNumberIndexInfo = createIndexInfo(stringType, /*isReadonly*/ true);
 
-        const globals = createMap<Symbol>();
+        const globals = new StringMap<Symbol>();
         /**
          * List of every ambient module with a "*" wildcard.
          * Unlike other ambient modules, these can't be stored in `globals` because symbol tables only deal with exact matches.
@@ -218,7 +218,7 @@ namespace ts {
         const mergedSymbols: Symbol[] = [];
         const symbolLinks: SymbolLinks[] = [];
         const nodeLinks: NodeLinks[] = [];
-        const flowLoopCaches: Map<Type>[] = [];
+        const flowLoopCaches: Map<string, Type>[] = [];
         const flowLoopNodes: FlowNode[] = [];
         const flowLoopKeys: string[] = [];
         const flowLoopTypes: Type[][] = [];
@@ -292,7 +292,7 @@ namespace ts {
             NullFacts = TypeofEQObject | TypeofNEString | TypeofNENumber | TypeofNEBoolean | TypeofNESymbol | TypeofNEFunction | TypeofNEHostObject | EQNull | EQUndefinedOrNull | NEUndefined | Falsy,
         }
 
-        const typeofEQFacts = createMap({
+        const typeofEQFacts = mapOfMapLike({
             "string": TypeFacts.TypeofEQString,
             "number": TypeFacts.TypeofEQNumber,
             "boolean": TypeFacts.TypeofEQBoolean,
@@ -302,7 +302,7 @@ namespace ts {
             "function": TypeFacts.TypeofEQFunction
         });
 
-        const typeofNEFacts = createMap({
+        const typeofNEFacts = mapOfMapLike({
             "string": TypeFacts.TypeofNEString,
             "number": TypeFacts.TypeofNENumber,
             "boolean": TypeFacts.TypeofNEBoolean,
@@ -312,7 +312,7 @@ namespace ts {
             "function": TypeFacts.TypeofNEFunction
         });
 
-        const typeofTypesByName = createMap<Type>({
+        const typeofTypesByName = mapOfMapLike<Type>({
             "string": stringType,
             "number": numberType,
             "boolean": booleanType,
@@ -322,7 +322,7 @@ namespace ts {
 
         let jsxElementType: ObjectType;
         /** Things we lazy load from the JSX namespace */
-        const jsxTypes = createMap<ObjectType>();
+        const jsxTypes = new StringMap<ObjectType>();
         const JsxNames = {
             JSX: "JSX",
             IntrinsicElements: "IntrinsicElements",
@@ -333,11 +333,11 @@ namespace ts {
             IntrinsicClassAttributes: "IntrinsicClassAttributes"
         };
 
-        const subtypeRelation = createMap<RelationComparisonResult>();
-        const assignableRelation = createMap<RelationComparisonResult>();
-        const comparableRelation = createMap<RelationComparisonResult>();
-        const identityRelation = createMap<RelationComparisonResult>();
-        const enumRelation = createMap<boolean>();
+        const subtypeRelation = new StringMap<RelationComparisonResult>();
+        const assignableRelation = new StringMap<RelationComparisonResult>();
+        const comparableRelation = new StringMap<RelationComparisonResult>();
+        const identityRelation = new StringMap<RelationComparisonResult>();
+        const enumRelation = new StringMap<boolean>();
 
         // This is for caching the result of getSymbolDisplayBuilder. Do not access directly.
         let _displayBuilder: SymbolDisplayBuilder;
@@ -351,8 +351,7 @@ namespace ts {
             ResolvedReturnType
         }
 
-        const builtinGlobals = createMap<Symbol>();
-        builtinGlobals[undefinedSymbol.name] = undefinedSymbol;
+        const builtinGlobals = createMapWithEntry(undefinedSymbol.name, undefinedSymbol);
 
         initializeTypeChecker();
 
@@ -435,11 +434,11 @@ namespace ts {
                     target.declarations.push(node);
                 });
                 if (source.members) {
-                    if (!target.members) target.members = createMap<Symbol>();
+                    if (!target.members) target.members = new StringMap<Symbol>();
                     mergeSymbolTable(target.members, source.members);
                 }
                 if (source.exports) {
-                    if (!target.exports) target.exports = createMap<Symbol>();
+                    if (!target.exports) target.exports = new StringMap<Symbol>();
                     mergeSymbolTable(target.exports, source.exports);
                 }
                 recordMergedSymbol(target, source);
@@ -457,18 +456,18 @@ namespace ts {
         }
 
         function mergeSymbolTable(target: SymbolTable, source: SymbolTable) {
-            for (const id in source) {
-                let targetSymbol = target[id];
+            source.forEach((sourceSymbol, id) => {
+                let targetSymbol = target.get(id);
                 if (!targetSymbol) {
-                    target[id] = source[id];
+                    target.set(id, sourceSymbol);
                 }
                 else {
                     if (!(targetSymbol.flags & SymbolFlags.Merged)) {
-                        target[id] = targetSymbol = cloneSymbol(targetSymbol);
+                        target.set(id, targetSymbol = cloneSymbol(targetSymbol));
                     }
-                    mergeSymbol(targetSymbol, source[id]);
+                    mergeSymbol(targetSymbol, sourceSymbol);
                 }
-            }
+            });
         }
 
         function mergeModuleAugmentation(moduleName: LiteralExpression): void {
@@ -509,15 +508,16 @@ namespace ts {
         }
 
         function addToSymbolTable(target: SymbolTable, source: SymbolTable, message: DiagnosticMessage) {
-            for (const id in source) {
-                if (target[id]) {
+            source.forEach((sourceSymbol, id) => {
+                const symbol = target.get(id);
+                if (symbol) {
                     // Error on redeclarations
-                    forEach(target[id].declarations, addDeclarationDiagnostic(id, message));
+                    forEach(symbol.declarations, addDeclarationDiagnostic(id, message));
                 }
                 else {
-                    target[id] = source[id];
+                    target.set(id, sourceSymbol);
                 }
-            }
+            });
 
             function addDeclarationDiagnostic(id: string, message: DiagnosticMessage) {
                 return (declaration: Declaration) => diagnostics.add(createDiagnosticForNode(declaration, message, id));
@@ -541,7 +541,7 @@ namespace ts {
 
         function getSymbol(symbols: SymbolTable, name: string, meaning: SymbolFlags): Symbol {
             if (meaning) {
-                const symbol = symbols[name];
+                const symbol = symbols.get(name);
                 if (symbol) {
                     Debug.assert((symbol.flags & SymbolFlags.Instantiated) === 0, "Should never get an instantiated symbol here.");
                     if (symbol.flags & meaning) {
@@ -722,7 +722,7 @@ namespace ts {
 
                             // It's an external module. First see if the module has an export default and if the local
                             // name of that export default matches.
-                            if (result = moduleExports["default"]) {
+                            if (result = moduleExports.get("default")) {
                                 const localSymbol = getLocalSymbolForExportDefault(result);
                                 if (localSymbol && (result.flags & meaning) && localSymbol.name === name) {
                                     break loop;
@@ -741,9 +741,10 @@ namespace ts {
                             //     2. We check === SymbolFlags.Alias in order to check that the symbol is *purely*
                             //        an alias. If we used &, we'd be throwing out symbols that have non alias aspects,
                             //        which is not the desired behavior.
-                            if (moduleExports[name] &&
-                                moduleExports[name].flags === SymbolFlags.Alias &&
-                                getDeclarationOfKind(moduleExports[name], SyntaxKind.ExportSpecifier)) {
+                            const moduleExport = moduleExports.get(name);
+                            if (moduleExport &&
+                                moduleExport.flags === SymbolFlags.Alias &&
+                                getDeclarationOfKind(moduleExport, SyntaxKind.ExportSpecifier)) {
                                 break;
                             }
                         }
@@ -1058,11 +1059,16 @@ namespace ts {
             const moduleSymbol = resolveExternalModuleName(node, (<ImportDeclaration>node.parent).moduleSpecifier);
 
             if (moduleSymbol) {
-                const exportDefaultSymbol = isShorthandAmbientModuleSymbol(moduleSymbol) ?
-                    moduleSymbol :
-                    moduleSymbol.exports["export="] ?
-                        getPropertyOfType(getTypeOfSymbol(moduleSymbol.exports["export="]), "default") :
-                        resolveSymbol(moduleSymbol.exports["default"]);
+                let exportDefaultSymbol: Symbol;
+                if (isShorthandAmbientModuleSymbol(moduleSymbol)) {
+                    exportDefaultSymbol = moduleSymbol;
+                }
+                else {
+                    const exportValue = moduleSymbol.exports.get("export=");
+                    exportDefaultSymbol = exportValue
+                        ? getPropertyOfType(getTypeOfSymbol(exportValue), "default")
+                        : resolveSymbol(moduleSymbol.exports.get("default"));
+                }
 
                 if (!exportDefaultSymbol && !allowSyntheticDefaultImports) {
                     error(node.name, Diagnostics.Module_0_has_no_default_export, symbolToString(moduleSymbol));
@@ -1112,7 +1118,7 @@ namespace ts {
 
         function getExportOfModule(symbol: Symbol, name: string): Symbol {
             if (symbol.flags & SymbolFlags.Module) {
-                const exportedSymbol = getExportsOfSymbol(symbol)[name];
+                const exportedSymbol = getExportsOfSymbol(symbol).get(name);
                 if (exportedSymbol) {
                     return resolveSymbol(exportedSymbol);
                 }
@@ -1140,7 +1146,7 @@ namespace ts {
 
                     let symbolFromVariable: Symbol;
                     // First check if module was specified with "export=". If so, get the member from the resolved type
-                    if (moduleSymbol && moduleSymbol.exports && moduleSymbol.exports["export="]) {
+                    if (moduleSymbol && moduleSymbol.exports && moduleSymbol.exports.get("export=")) {
                         symbolFromVariable = getPropertyOfType(getTypeOfSymbol(targetSymbol), name.text);
                     }
                     else {
@@ -1400,7 +1406,7 @@ namespace ts {
         // An external module with an 'export =' declaration resolves to the target of the 'export =' declaration,
         // and an external module with no 'export =' declaration resolves to the module itself.
         function resolveExternalModuleSymbol(moduleSymbol: Symbol): Symbol {
-            return moduleSymbol && getMergedSymbol(resolveSymbol(moduleSymbol.exports["export="])) || moduleSymbol;
+            return moduleSymbol && getMergedSymbol(resolveSymbol(moduleSymbol.exports.get("export="))) || moduleSymbol;
         }
 
         // An external module with an 'export =' declaration may be referenced as an ES6 module provided the 'export ='
@@ -1416,7 +1422,7 @@ namespace ts {
         }
 
         function hasExportAssignmentSymbol(moduleSymbol: Symbol): boolean {
-            return moduleSymbol.exports["export="] !== undefined;
+            return moduleSymbol.exports.get("export=") !== undefined;
         }
 
         function getExportsOfModuleAsArray(moduleSymbol: Symbol): Symbol[] {
@@ -1441,25 +1447,29 @@ namespace ts {
          * Extends one symbol table with another while collecting information on name collisions for error message generation into the `lookupTable` argument
          * Not passing `lookupTable` and `exportNode` disables this collection, and just extends the tables
          */
-        function extendExportSymbols(target: SymbolTable, source: SymbolTable, lookupTable?: Map<ExportCollisionTracker>, exportNode?: ExportDeclaration) {
-            for (const id in source) {
-                if (id !== "default" && !target[id]) {
-                    target[id] = source[id];
+        function extendExportSymbols(target: SymbolTable, source: SymbolTable, lookupTable?: Map<string, ExportCollisionTracker>, exportNode?: ExportDeclaration) {
+            if (!source) return;
+
+            source.forEach((sourceSymbol, id) => {
+                const targetSymbol = target.get(id);
+                if (id !== "default" && !targetSymbol) {
+                    target.set(id, sourceSymbol);
                     if (lookupTable && exportNode) {
-                        lookupTable[id] = {
+                        lookupTable.set(id, {
                             specifierText: getTextOfNode(exportNode.moduleSpecifier)
-                        } as ExportCollisionTracker;
+                        } as ExportCollisionTracker);
                     }
                 }
-                else if (lookupTable && exportNode && id !== "default" && target[id] && resolveSymbol(target[id]) !== resolveSymbol(source[id])) {
-                    if (!lookupTable[id].exportsWithDuplicate) {
-                        lookupTable[id].exportsWithDuplicate = [exportNode];
+                else if (lookupTable && exportNode && id !== "default" && targetSymbol && resolveSymbol(targetSymbol) !== resolveSymbol(sourceSymbol)) {
+                    const collisionTracker = lookupTable.get(id);
+                    if (!collisionTracker.exportsWithDuplicate) {
+                        collisionTracker.exportsWithDuplicate = [exportNode];
                     }
                     else {
-                        lookupTable[id].exportsWithDuplicate.push(exportNode);
+                        collisionTracker.exportsWithDuplicate.push(exportNode);
                     }
                 }
-            }
+            });
         }
 
         function getExportsForModule(moduleSymbol: Symbol): SymbolTable {
@@ -1475,10 +1485,10 @@ namespace ts {
                 visitedSymbols.push(symbol);
                 const symbols = cloneMap(symbol.exports);
                 // All export * declarations are collected in an __export symbol by the binder
-                const exportStars = symbol.exports["__export"];
+                const exportStars = symbol.exports.get("__export");
                 if (exportStars) {
-                    const nestedSymbols = createMap<Symbol>();
-                    const lookupTable = createMap<ExportCollisionTracker>();
+                    const nestedSymbols = new StringMap<Symbol>();
+                    const lookupTable = new StringMap<ExportCollisionTracker>();
                     for (const node of exportStars.declarations) {
                         const resolvedModule = resolveExternalModuleName(node, (node as ExportDeclaration).moduleSpecifier);
                         const exportedSymbols = visit(resolvedModule);
@@ -1489,21 +1499,20 @@ namespace ts {
                             node as ExportDeclaration
                         );
                     }
-                    for (const id in lookupTable) {
-                        const { exportsWithDuplicate } = lookupTable[id];
+                    lookupTable.forEach(({ exportsWithDuplicate }, id) => {
                         // It's not an error if the file with multiple `export *`s with duplicate names exports a member with that name itself
-                        if (id === "export=" || !(exportsWithDuplicate && exportsWithDuplicate.length) || symbols[id]) {
-                            continue;
+                        if (id === "export=" || !(exportsWithDuplicate && exportsWithDuplicate.length) || symbols.get(id)) {
+                            return;
                         }
                         for (const node of exportsWithDuplicate) {
                             diagnostics.add(createDiagnosticForNode(
                                 node,
                                 Diagnostics.Module_0_has_already_exported_a_member_named_1_Consider_explicitly_re_exporting_to_resolve_the_ambiguity,
-                                lookupTable[id].specifierText,
+                                lookupTable.get(id).specifierText,
                                 id
                             ));
                         }
-                    }
+                    });
                     extendExportSymbols(symbols, nestedSymbols);
                 }
                 return symbols;
@@ -1597,15 +1606,14 @@ namespace ts {
 
         function getNamedMembers(members: SymbolTable): Symbol[] {
             let result: Symbol[];
-            for (const id in members) {
+            members.forEach((symbol, id) => {
                 if (!isReservedMemberName(id)) {
                     if (!result) result = [];
-                    const symbol = members[id];
                     if (symbolIsValue(symbol)) {
                         result.push(symbol);
                     }
                 }
-            }
+            });
             return result || emptyArray;
         }
 
@@ -1678,12 +1686,12 @@ namespace ts {
                 }
 
                 // If symbol is directly available by its name in the symbol table
-                if (isAccessible(symbols[symbol.name])) {
+                if (isAccessible(symbols.get(symbol.name))) {
                     return [symbol];
                 }
 
                 // Check if symbol is any of the alias
-                return forEachProperty(symbols, symbolFromSymbolTable => {
+                return findInMap(symbols, symbolFromSymbolTable => {
                     if (symbolFromSymbolTable.flags & SymbolFlags.Alias
                         && symbolFromSymbolTable.name !== "export="
                         && !getDeclarationOfKind(symbolFromSymbolTable, SyntaxKind.ExportSpecifier)) {
@@ -1718,7 +1726,7 @@ namespace ts {
             let qualify = false;
             forEachSymbolTableInScope(enclosingDeclaration, symbolTable => {
                 // If symbol of this name is not available in the symbol table we are ok
-                let symbolFromSymbolTable = symbolTable[symbol.name];
+                let symbolFromSymbolTable = symbolTable.get(symbol.name);
                 if (!symbolFromSymbolTable) {
                     // Continue to the next symbol table
                     return false;
@@ -2455,7 +2463,7 @@ namespace ts {
                     }
                     writeIndexSignature(resolved.stringIndexInfo, SyntaxKind.StringKeyword);
                     writeIndexSignature(resolved.numberIndexInfo, SyntaxKind.NumberKeyword);
-                    for (const p of resolved.properties) {
+                    for (const p of sortInV8ObjectInsertionOrder(resolved.properties, p => p.name)) {
                         const t = getTypeOfSymbol(p);
                         if (p.flags & (SymbolFlags.Function | SymbolFlags.Method) && !getPropertiesOfObjectType(t).length) {
                             const signatures = getSignaturesOfType(t, SignatureKind.Call);
@@ -3162,7 +3170,7 @@ namespace ts {
 
         // Return the type implied by an object binding pattern
         function getTypeFromObjectBindingPattern(pattern: ObjectBindingPattern, includePatternInType: boolean, reportErrors: boolean): Type {
-            const members = createMap<Symbol>();
+            const members = new StringMap<Symbol>();
             let hasComputedProperties = false;
             forEach(pattern.elements, e => {
                 const name = e.propertyName || <Identifier>e.name;
@@ -3177,7 +3185,7 @@ namespace ts {
                 const symbol = <TransientSymbol>createSymbol(flags, text);
                 symbol.type = getTypeFromBindingElement(e, includePatternInType, reportErrors);
                 symbol.bindingElement = e;
-                members[symbol.name] = symbol;
+                members.set(symbol.name, symbol);
             });
             const result = createAnonymousType(undefined, members, emptyArray, emptyArray, undefined, undefined);
             if (includePatternInType) {
@@ -3767,8 +3775,7 @@ namespace ts {
                     type.typeParameters = concatenate(outerTypeParameters, localTypeParameters);
                     type.outerTypeParameters = outerTypeParameters;
                     type.localTypeParameters = localTypeParameters;
-                    (<GenericType>type).instantiations = createMap<TypeReference>();
-                    (<GenericType>type).instantiations[getTypeListId(type.typeParameters)] = <GenericType>type;
+                    (<GenericType>type).instantiations = createMapWithEntry(getTypeListId(type.typeParameters), <GenericType>type);
                     (<GenericType>type).target = <GenericType>type;
                     (<GenericType>type).typeArguments = type.typeParameters;
                     type.thisType = <TypeParameter>createType(TypeFlags.TypeParameter);
@@ -3810,8 +3817,7 @@ namespace ts {
                     if (typeParameters) {
                         // Initialize the instantiation cache for generic type aliases. The declared type corresponds to
                         // an instantiation of the type alias with the type parameters supplied as type arguments.
-                        links.instantiations = createMap<Type>();
-                        links.instantiations[getTypeListId(links.typeParameters)] = type;
+                        links.instantiations = createMapWithEntry(getTypeListId(links.typeParameters), type);
                     }
                 }
                 else {
@@ -3831,7 +3837,7 @@ namespace ts {
             return expr.kind === SyntaxKind.NumericLiteral ||
                 expr.kind === SyntaxKind.PrefixUnaryExpression && (<PrefixUnaryExpression>expr).operator === SyntaxKind.MinusToken &&
                 (<PrefixUnaryExpression>expr).operand.kind === SyntaxKind.NumericLiteral ||
-                expr.kind === SyntaxKind.Identifier && !!symbol.exports[(<Identifier>expr).text];
+                expr.kind === SyntaxKind.Identifier && !!symbol.exports.get((<Identifier>expr).text);
         }
 
         function enumHasLiteralMembers(symbol: Symbol) {
@@ -3862,16 +3868,15 @@ namespace ts {
                 enumType.symbol = symbol;
                 if (enumHasLiteralMembers(symbol)) {
                     const memberTypeList: Type[] = [];
-                    const memberTypes = createMap<EnumLiteralType>();
+                    const memberTypes = new NumberMap<number, EnumLiteralType>();
                     for (const declaration of enumType.symbol.declarations) {
                         if (declaration.kind === SyntaxKind.EnumDeclaration) {
                             computeEnumMemberValues(<EnumDeclaration>declaration);
                             for (const member of (<EnumDeclaration>declaration).members) {
                                 const memberSymbol = getSymbolOfNode(member);
                                 const value = getEnumMemberValue(member);
-                                if (!memberTypes[value]) {
-                                    const memberType = memberTypes[value] = createEnumLiteralType(memberSymbol, enumType, "" + value);
-                                    memberTypeList.push(memberType);
+                                if (!memberTypes.get(value)) {
+                                    memberTypeList.push(setAndReturn(memberTypes, value, createEnumLiteralType(memberSymbol, enumType, "" + value)));
                                 }
                             }
                         }
@@ -3880,7 +3885,7 @@ namespace ts {
                     if (memberTypeList.length > 1) {
                         enumType.flags |= TypeFlags.Union;
                         (<EnumType & UnionType>enumType).types = memberTypeList;
-                        unionTypes[getTypeListId(memberTypeList)] = <EnumType & UnionType>enumType;
+                        unionTypes.set(getTypeListId(memberTypeList), <EnumType & UnionType>enumType);
                     }
                 }
             }
@@ -3892,7 +3897,7 @@ namespace ts {
             if (!links.declaredType) {
                 const enumType = <EnumType>getDeclaredTypeOfEnum(getParentOfSymbol(symbol));
                 links.declaredType = enumType.flags & TypeFlags.Union ?
-                    enumType.memberTypes[getEnumMemberValue(<EnumDeclaration>symbol.valueDeclaration)] :
+                    enumType.memberTypes.get(getEnumMemberValue(<EnumDeclaration>symbol.valueDeclaration)) :
                     enumType;
             }
             return links.declaredType;
@@ -4022,27 +4027,19 @@ namespace ts {
         }
 
         function createSymbolTable(symbols: Symbol[]): SymbolTable {
-            const result = createMap<Symbol>();
-            for (const symbol of symbols) {
-                result[symbol.name] = symbol;
-            }
-            return result;
+            return arrayToMap(symbols, symbol => symbol.name);
         }
 
         // The mappingThisOnly flag indicates that the only type parameter being mapped is "this". When the flag is true,
         // we check symbols to see if we can quickly conclude they are free of "this" references, thus needing no instantiation.
         function createInstantiatedSymbolTable(symbols: Symbol[], mapper: TypeMapper, mappingThisOnly: boolean): SymbolTable {
-            const result = createMap<Symbol>();
-            for (const symbol of symbols) {
-                result[symbol.name] = mappingThisOnly && isIndependentMember(symbol) ? symbol : instantiateSymbol(symbol, mapper);
-            }
-            return result;
+            return arrayToMap(symbols, symbol => symbol.name, symbol => mappingThisOnly && isIndependentMember(symbol) ? symbol : instantiateSymbol(symbol, mapper));
         }
 
         function addInheritedMembers(symbols: SymbolTable, baseSymbols: Symbol[]) {
             for (const s of baseSymbols) {
-                if (!symbols[s.name]) {
-                    symbols[s.name] = s;
+                if (!symbols.get(s.name)) {
+                    symbols.set(s.name, s);
                 }
             }
         }
@@ -4051,8 +4048,8 @@ namespace ts {
             if (!(<InterfaceTypeWithDeclaredMembers>type).declaredProperties) {
                 const symbol = type.symbol;
                 (<InterfaceTypeWithDeclaredMembers>type).declaredProperties = getNamedMembers(symbol.members);
-                (<InterfaceTypeWithDeclaredMembers>type).declaredCallSignatures = getSignaturesOfSymbol(symbol.members["__call"]);
-                (<InterfaceTypeWithDeclaredMembers>type).declaredConstructSignatures = getSignaturesOfSymbol(symbol.members["__new"]);
+                (<InterfaceTypeWithDeclaredMembers>type).declaredCallSignatures = getSignaturesOfSymbol(symbol.members.get("__call"));
+                (<InterfaceTypeWithDeclaredMembers>type).declaredConstructSignatures = getSignaturesOfSymbol(symbol.members.get("__new"));
                 (<InterfaceTypeWithDeclaredMembers>type).declaredStringIndexInfo = getIndexInfoOfSymbol(symbol, IndexKind.String);
                 (<InterfaceTypeWithDeclaredMembers>type).declaredNumberIndexInfo = getIndexInfoOfSymbol(symbol, IndexKind.Number);
             }
@@ -4292,8 +4289,8 @@ namespace ts {
             }
             else if (symbol.flags & SymbolFlags.TypeLiteral) {
                 const members = symbol.members;
-                const callSignatures = getSignaturesOfSymbol(members["__call"]);
-                const constructSignatures = getSignaturesOfSymbol(members["__new"]);
+                const callSignatures = getSignaturesOfSymbol(members.get("__call"));
+                const constructSignatures = getSignaturesOfSymbol(members.get("__new"));
                 const stringIndexInfo = getIndexInfoOfSymbol(symbol, IndexKind.String);
                 const numberIndexInfo = getIndexInfoOfSymbol(symbol, IndexKind.Number);
                 setObjectTypeMembers(type, members, callSignatures, constructSignatures, stringIndexInfo, numberIndexInfo);
@@ -4307,7 +4304,7 @@ namespace ts {
                 }
                 if (symbol.flags & SymbolFlags.Class) {
                     const classType = getDeclaredTypeOfClassOrInterface(symbol);
-                    constructSignatures = getSignaturesOfSymbol(symbol.members["__constructor"]);
+                    constructSignatures = getSignaturesOfSymbol(symbol.members.get("__constructor"));
                     if (!constructSignatures.length) {
                         constructSignatures = getDefaultConstructSignatures(classType);
                     }
@@ -4363,7 +4360,7 @@ namespace ts {
         function getPropertyOfObjectType(type: Type, name: string): Symbol {
             if (type.flags & TypeFlags.ObjectType) {
                 const resolved = resolveStructuredTypeMembers(<ObjectType>type);
-                const symbol = resolved.members[name];
+                const symbol = resolved.members.get(name);
                 if (symbol && symbolIsValue(symbol)) {
                     return symbol;
                 }
@@ -4384,13 +4381,12 @@ namespace ts {
             const props = type.resolvedProperties;
             if (props) {
                 const result: Symbol[] = [];
-                for (const key in props) {
-                    const prop = props[key];
+                props.forEach((prop, key) =>  {
                     // We need to filter out partial properties in union types
                     if (!(prop.flags & SymbolFlags.SyntheticProperty && (<TransientSymbol>prop).isPartial)) {
                         result.push(prop);
                     }
-                }
+                });
                 return result;
             }
             return emptyArray;
@@ -4507,12 +4503,12 @@ namespace ts {
         // these partial properties when identifying discriminant properties, but otherwise they are filtered out
         // and do not appear to be present in the union type.
         function getUnionOrIntersectionProperty(type: UnionOrIntersectionType, name: string): Symbol {
-            const properties = type.resolvedProperties || (type.resolvedProperties = createMap<Symbol>());
-            let property = properties[name];
+            const properties = type.resolvedProperties || (type.resolvedProperties = new StringMap<Symbol>());
+            let property = properties.get(name);
             if (!property) {
                 property = createUnionOrIntersectionProperty(type, name);
                 if (property) {
-                    properties[name] = property;
+                    properties.set(name, property);
                 }
             }
             return property;
@@ -4536,7 +4532,7 @@ namespace ts {
             type = getApparentType(type);
             if (type.flags & TypeFlags.ObjectType) {
                 const resolved = resolveStructuredTypeMembers(type);
-                const symbol = resolved.members[name];
+                const symbol = resolved.members.get(name);
                 if (symbol && symbolIsValue(symbol)) {
                     return symbol;
                 }
@@ -4635,11 +4631,11 @@ namespace ts {
 
         function symbolsToArray(symbols: SymbolTable): Symbol[] {
             const result: Symbol[] = [];
-            for (const id in symbols) {
+            symbols.forEach((symbol, id) => {
                 if (!isReservedMemberName(id)) {
-                    result.push(symbols[id]);
+                    result.push(symbol);
                 }
-            }
+            });
             return result;
         }
 
@@ -4934,7 +4930,7 @@ namespace ts {
         }
 
         function getIndexSymbol(symbol: Symbol): Symbol {
-            return symbol.members["__index"];
+            return symbol.members.get("__index");
         }
 
         function getIndexDeclarationOfSymbol(symbol: Symbol, kind: IndexKind): SignatureDeclaration {
@@ -5048,11 +5044,11 @@ namespace ts {
 
         function createTypeReference(target: GenericType, typeArguments: Type[]): TypeReference {
             const id = getTypeListId(typeArguments);
-            let type = target.instantiations[id];
+            let type = target.instantiations.get(id);
             if (!type) {
                 const propagatedFlags = typeArguments ? getPropagatingFlagsOfTypes(typeArguments, /*excludeKinds*/ 0) : 0;
                 const flags = TypeFlags.Reference | propagatedFlags;
-                type = target.instantiations[id] = <TypeReference>createObjectType(flags, target.symbol);
+                type = setAndReturn(target.instantiations, id, <TypeReference>createObjectType(flags, target.symbol));
                 type.target = target;
                 type.typeArguments = typeArguments;
             }
@@ -5105,7 +5101,7 @@ namespace ts {
                 }
                 const typeArguments = map(node.typeArguments, getTypeFromTypeNodeNoAlias);
                 const id = getTypeListId(typeArguments);
-                return links.instantiations[id] || (links.instantiations[id] = instantiateType(type, createTypeMapper(typeParameters, typeArguments)));
+                return links.instantiations.get(id) || setAndReturn(links.instantiations, id, instantiateType(type, createTypeMapper(typeParameters, typeArguments)));
             }
             if (node.typeArguments) {
                 error(node, Diagnostics.Type_0_is_not_generic, symbolToString(symbol));
@@ -5333,8 +5329,7 @@ namespace ts {
             type.typeParameters = typeParameters;
             type.outerTypeParameters = undefined;
             type.localTypeParameters = typeParameters;
-            type.instantiations = createMap<TypeReference>();
-            type.instantiations[getTypeListId(type.typeParameters)] = <GenericType>type;
+            type.instantiations = createMapWithEntry(getTypeListId(type.typeParameters), <GenericType>type);
             type.target = <GenericType>type;
             type.typeArguments = type.typeParameters;
             type.thisType = <TypeParameter>createType(TypeFlags.TypeParameter);
@@ -5537,10 +5532,10 @@ namespace ts {
                 return types[0];
             }
             const id = getTypeListId(types);
-            let type = unionTypes[id];
+            let type = unionTypes.get(id);
             if (!type) {
                 const propagatedFlags = getPropagatingFlagsOfTypes(types, /*excludeKinds*/ TypeFlags.Nullable);
-                type = unionTypes[id] = <UnionType>createObjectType(TypeFlags.Union | propagatedFlags);
+                type = setAndReturn(unionTypes, id, <UnionType>createObjectType(TypeFlags.Union | propagatedFlags));
                 type.types = types;
                 type.aliasSymbol = aliasSymbol;
                 type.aliasTypeArguments = aliasTypeArguments;
@@ -5594,10 +5589,10 @@ namespace ts {
                 return typeSet[0];
             }
             const id = getTypeListId(typeSet);
-            let type = intersectionTypes[id];
+            let type = intersectionTypes.get(id);
             if (!type) {
                 const propagatedFlags = getPropagatingFlagsOfTypes(typeSet, /*excludeKinds*/ TypeFlags.Nullable);
-                type = intersectionTypes[id] = <IntersectionType>createObjectType(TypeFlags.Intersection | propagatedFlags);
+                type = setAndReturn(intersectionTypes, id, <IntersectionType>createObjectType(TypeFlags.Intersection | propagatedFlags));
                 type.types = typeSet;
                 type.aliasSymbol = aliasSymbol;
                 type.aliasTypeArguments = aliasTypeArguments;
@@ -5649,7 +5644,7 @@ namespace ts {
 
         function getLiteralTypeForText(flags: TypeFlags, text: string) {
             const map = flags & TypeFlags.StringLiteral ? stringLiteralTypes : numericLiteralTypes;
-            return map[text] || (map[text] = createLiteralType(flags, text));
+            return map.get(text) || setAndReturn(map, text, createLiteralType(flags, text));
         }
 
         function getTypeFromLiteralTypeNode(node: LiteralTypeNode): Type {
@@ -6328,13 +6323,14 @@ namespace ts {
                 return true;
             }
             const id = source.id + "," + target.id;
-            if (enumRelation[id] !== undefined) {
-                return enumRelation[id];
+            const relation = enumRelation.get(id);
+            if (relation !== undefined) {
+                return relation;
             }
             if (source.symbol.name !== target.symbol.name ||
                 !(source.symbol.flags & SymbolFlags.RegularEnum) || !(target.symbol.flags & SymbolFlags.RegularEnum) ||
                 (source.flags & TypeFlags.Union) !== (target.flags & TypeFlags.Union)) {
-                return enumRelation[id] = false;
+                return setAndReturn(enumRelation, id, false);
             }
             const targetEnumType = getTypeOfSymbol(target.symbol);
             for (const property of getPropertiesOfType(getTypeOfSymbol(source.symbol))) {
@@ -6345,14 +6341,14 @@ namespace ts {
                             errorReporter(Diagnostics.Property_0_is_missing_in_type_1, property.name,
                                 typeToString(target, /*enclosingDeclaration*/ undefined, TypeFormatFlags.UseFullyQualifiedType));
                         }
-                        return enumRelation[id] = false;
+                        return setAndReturn(enumRelation, id, false);
                     }
                 }
             }
-            return enumRelation[id] = true;
+            return setAndReturn(enumRelation, id, true);
         }
 
-        function isSimpleTypeRelatedTo(source: Type, target: Type, relation: Map<RelationComparisonResult>, errorReporter?: ErrorReporter) {
+        function isSimpleTypeRelatedTo(source: Type, target: Type, relation: Map<string, RelationComparisonResult>, errorReporter?: ErrorReporter) {
             if (target.flags & TypeFlags.Never) return false;
             if (target.flags & TypeFlags.Any || source.flags & TypeFlags.Never) return true;
             if (source.flags & TypeFlags.StringLike && target.flags & TypeFlags.String) return true;
@@ -6380,7 +6376,7 @@ namespace ts {
             return false;
         }
 
-        function isTypeRelatedTo(source: Type, target: Type, relation: Map<RelationComparisonResult>) {
+        function isTypeRelatedTo(source: Type, target: Type, relation: Map<string, RelationComparisonResult>) {
             if (source.flags & TypeFlags.StringOrNumberLiteral && source.flags & TypeFlags.FreshLiteral) {
                 source = (<LiteralType>source).regularType;
             }
@@ -6392,7 +6388,7 @@ namespace ts {
             }
             if (source.flags & TypeFlags.ObjectType && target.flags & TypeFlags.ObjectType) {
                 const id = relation !== identityRelation || source.id < target.id ? source.id + "," + target.id : target.id + "," + source.id;
-                const related = relation[id];
+                const related = relation.get(id);
                 if (related !== undefined) {
                     return related === RelationComparisonResult.Succeeded;
                 }
@@ -6416,7 +6412,7 @@ namespace ts {
         function checkTypeRelatedTo(
             source: Type,
             target: Type,
-            relation: Map<RelationComparisonResult>,
+            relation: Map<string, RelationComparisonResult>,
             errorNode: Node,
             headMessage?: DiagnosticMessage,
             containingMessageChain?: DiagnosticMessageChain): boolean {
@@ -6424,7 +6420,7 @@ namespace ts {
             let errorInfo: DiagnosticMessageChain;
             let sourceStack: ObjectType[];
             let targetStack: ObjectType[];
-            let maybeStack: Map<RelationComparisonResult>[];
+            let maybeStack: Map<string, RelationComparisonResult>[];
             let expandingFlags: number;
             let depth = 0;
             let overflow = false;
@@ -6790,12 +6786,12 @@ namespace ts {
                     return Ternary.False;
                 }
                 const id = relation !== identityRelation || source.id < target.id ? source.id + "," + target.id : target.id + "," + source.id;
-                const related = relation[id];
+                const related = relation.get(id);
                 if (related !== undefined) {
                     if (reportErrors && related === RelationComparisonResult.Failed) {
                         // We are elaborating errors and the cached result is an unreported failure. Record the result as a reported
                         // failure and continue computing the relation such that errors get reported.
-                        relation[id] = RelationComparisonResult.FailedAndReported;
+                        relation.set(id, RelationComparisonResult.FailedAndReported);
                     }
                     else {
                         return related === RelationComparisonResult.Succeeded ? Ternary.True : Ternary.False;
@@ -6804,7 +6800,7 @@ namespace ts {
                 if (depth > 0) {
                     for (let i = 0; i < depth; i++) {
                         // If source and target are already being compared, consider them related with assumptions
-                        if (maybeStack[i][id]) {
+                        if (maybeStack[i].get(id)) {
                             return Ternary.Maybe;
                         }
                     }
@@ -6821,8 +6817,7 @@ namespace ts {
                 }
                 sourceStack[depth] = source;
                 targetStack[depth] = target;
-                maybeStack[depth] = createMap<RelationComparisonResult>();
-                maybeStack[depth][id] = RelationComparisonResult.Succeeded;
+                maybeStack[depth] = createMapWithEntry(id, RelationComparisonResult.Succeeded);
                 depth++;
                 const saveExpandingFlags = expandingFlags;
                 if (!(expandingFlags & 1) && isDeeplyNestedGeneric(source, sourceStack, depth)) expandingFlags |= 1;
@@ -6852,12 +6847,12 @@ namespace ts {
                     const maybeCache = maybeStack[depth];
                     // If result is definitely true, copy assumptions to global cache, else copy to next level up
                     const destinationCache = (result === Ternary.True || depth === 0) ? relation : maybeStack[depth - 1];
-                    copyProperties(maybeCache, destinationCache);
+                    copyMapEntriesFromTo(maybeCache, destinationCache);
                 }
                 else {
                     // A false result goes straight into global cache (when something is false under assumptions it
                     // will also be false without assumptions)
-                    relation[id] = reportErrors ? RelationComparisonResult.FailedAndReported : RelationComparisonResult.Failed;
+                    relation.set(id, reportErrors ? RelationComparisonResult.FailedAndReported : RelationComparisonResult.Failed);
                 }
                 return result;
             }
@@ -7046,14 +7041,29 @@ namespace ts {
                 return result;
             }
 
-            function eachPropertyRelatedTo(source: Type, target: Type, kind: IndexKind, reportErrors: boolean): Ternary {
+            /**
+             * For consistency we report the first error in V8 object insertion order.
+             * Since that's slow and there usually isn't an error, we only sort properties the second time around.
+             */
+            function eachPropertyRelatedTo(source: Type, target: Type, kind: IndexKind, reportErrors: boolean, redoingInV8ObjectInsertionOrder?: boolean): Ternary {
                 let result = Ternary.True;
-                for (const prop of getPropertiesOfObjectType(source)) {
+                let properties = getPropertiesOfObjectType(source);
+                if (redoingInV8ObjectInsertionOrder) {
+                    properties = sortInV8ObjectInsertionOrder(properties, prop => prop.name);
+                }
+                for (const prop of properties) {
                     if (kind === IndexKind.String || isNumericLiteralName(prop.name)) {
-                        const related = isRelatedTo(getTypeOfSymbol(prop), target, reportErrors);
+                        const related = isRelatedTo(getTypeOfSymbol(prop), target, reportErrors && redoingInV8ObjectInsertionOrder);
                         if (!related) {
                             if (reportErrors) {
-                                reportError(Diagnostics.Property_0_is_incompatible_with_index_signature, symbolToString(prop));
+                                // For consistency, if we report errors we make sure to report the first error in V8's object insertion order.
+                                if (!redoingInV8ObjectInsertionOrder) {
+                                    const related = eachPropertyRelatedTo(source,  target, kind, reportErrors, /*redoingInV8ObjectInsertionOrder*/ true);
+                                    Debug.assert(related === Ternary.False);
+                                }
+                                else {
+                                    reportError(Diagnostics.Property_0_is_incompatible_with_index_signature, symbolToString(prop));
+                                }
                             }
                             return Ternary.False;
                         }
@@ -7492,11 +7502,11 @@ namespace ts {
         }
 
         function transformTypeOfMembers(type: Type, f: (propertyType: Type) => Type) {
-            const members = createMap<Symbol>();
+            const members = new StringMap<Symbol>();
             for (const property of getPropertiesOfObjectType(type)) {
                 const original = getTypeOfSymbol(property);
                 const updated = f(original);
-                members[property.name] = updated === original ? property : createTransientSymbol(property, updated);
+                members.set(property.name, updated === original ? property : createTransientSymbol(property, updated));
             };
             return members;
         }
@@ -7714,7 +7724,7 @@ namespace ts {
             let targetStack: Type[];
             let depth = 0;
             let inferiority = 0;
-            const visited = createMap<boolean>();
+            const visited = new StringSet();
             inferFromTypes(originalSource, originalTarget);
 
             function isInProcess(source: Type, target: Type) {
@@ -7850,10 +7860,10 @@ namespace ts {
                             return;
                         }
                         const key = source.id + "," + target.id;
-                        if (visited[key]) {
+                        if (visited.has(key)) {
                             return;
                         }
-                        visited[key] = true;
+                        visited.add(key);
                         if (depth === 0) {
                             sourceStack = [];
                             targetStack = [];
@@ -8204,7 +8214,7 @@ namespace ts {
             // check. This gives us a quicker out in the common case where an object type is not a function.
             const resolved = resolveStructuredTypeMembers(type);
             return !!(resolved.callSignatures.length || resolved.constructSignatures.length ||
-                resolved.members["bind"] && isTypeSubtypeOf(type, globalFunctionType));
+                resolved.members.get("bind") && isTypeSubtypeOf(type, globalFunctionType));
         }
 
         function getTypeFacts(type: Type): TypeFacts {
@@ -8617,12 +8627,13 @@ namespace ts {
                 // If we have previously computed the control flow type for the reference at
                 // this flow loop junction, return the cached type.
                 const id = getFlowNodeId(flow);
-                const cache = flowLoopCaches[id] || (flowLoopCaches[id] = createMap<Type>());
+                const cache = flowLoopCaches[id] || (flowLoopCaches[id] = new StringMap<Type>());
                 if (!key) {
                     key = getFlowCacheKey(reference);
                 }
-                if (cache[key]) {
-                    return cache[key];
+                const cached = cache.get(key);
+                if (cached) {
+                    return cached;
                 }
                 // If this flow loop junction and reference are already being processed, return
                 // the union of the types computed for each branch so far, marked as incomplete.
@@ -8652,8 +8663,9 @@ namespace ts {
                     // If we see a value appear in the cache it is a sign that control flow  analysis
                     // was restarted and completed by checkExpressionCached. We can simply pick up
                     // the resulting type and bail out.
-                    if (cache[key]) {
-                        return cache[key];
+                    const cached = cache.get(key);
+                    if (cached) {
+                        return cached;
                     }
                     if (!contains(antecedentTypes, type)) {
                         antecedentTypes.push(type);
@@ -8677,7 +8689,7 @@ namespace ts {
                 if (isIncomplete(firstAntecedentType)) {
                     return createFlowType(result, /*incomplete*/ true);
                 }
-                return cache[key] = result;
+                return setAndReturn(cache, key, result);
             }
 
             function isMatchingReferenceDiscriminant(expr: Expression) {
@@ -8800,14 +8812,14 @@ namespace ts {
                     // We narrow a non-union type to an exact primitive type if the non-union type
                     // is a supertype of that primitive type. For example, type 'any' can be narrowed
                     // to one of the primitive types.
-                    const targetType = typeofTypesByName[literal.text];
+                    const targetType = typeofTypesByName.get(literal.text);
                     if (targetType && isTypeSubtypeOf(targetType, type)) {
                         return targetType;
                     }
                 }
                 const facts = assumeTrue ?
-                    typeofEQFacts[literal.text] || TypeFacts.TypeofEQHostObject :
-                    typeofNEFacts[literal.text] || TypeFacts.TypeofNEHostObject;
+                    typeofEQFacts.get(literal.text) || TypeFacts.TypeofEQHostObject :
+                    typeofNEFacts.get(literal.text) || TypeFacts.TypeofNEHostObject;
                 return getTypeWithFacts(type, facts);
             }
 
@@ -10293,7 +10305,7 @@ namespace ts {
             // Grammar checking
             checkGrammarObjectLiteralExpression(node, inDestructuringPattern);
 
-            const propertiesTable = createMap<Symbol>();
+            const propertiesTable = new StringMap<Symbol>();
             const propertiesArray: Symbol[] = [];
             const contextualType = getApparentTypeOfContextualType(node);
             const contextualTypeHasPattern = contextualType && contextualType.pattern &&
@@ -10376,7 +10388,7 @@ namespace ts {
                     }
                 }
                 else {
-                    propertiesTable[member.name] = member;
+                    propertiesTable.set(member.name, member);
                 }
                 propertiesArray.push(member);
             }
@@ -10385,12 +10397,12 @@ namespace ts {
             // type with those properties for which the binding pattern specifies a default value.
             if (contextualTypeHasPattern) {
                 for (const prop of getPropertiesOfType(contextualType)) {
-                    if (!propertiesTable[prop.name]) {
+                    if (!propertiesTable.get(prop.name)) {
                         if (!(prop.flags & SymbolFlags.Optional)) {
                             error(prop.valueDeclaration || (<TransientSymbol>prop).bindingElement,
                                 Diagnostics.Initializer_provides_no_value_for_this_binding_element_and_the_binding_element_has_no_default_value);
                         }
-                        propertiesTable[prop.name] = prop;
+                        propertiesTable.set(prop.name, prop);
                         propertiesArray.push(prop);
                     }
                 }
@@ -10466,7 +10478,7 @@ namespace ts {
             }
         }
 
-        function checkJsxAttribute(node: JsxAttribute, elementAttributesType: Type, nameTable: Map<boolean>) {
+        function checkJsxAttribute(node: JsxAttribute, elementAttributesType: Type, nameTable: Set<string>) {
             let correspondingPropType: Type = undefined;
 
             // Look up the corresponding property for this attribute
@@ -10505,34 +10517,35 @@ namespace ts {
                 checkTypeAssignableTo(exprType, correspondingPropType, node);
             }
 
-            nameTable[node.name.text] = true;
+            nameTable.add(node.name.text);
             return exprType;
         }
 
-        function checkJsxSpreadAttribute(node: JsxSpreadAttribute, elementAttributesType: Type, nameTable: Map<boolean>) {
+        function checkJsxSpreadAttribute(node: JsxSpreadAttribute, elementAttributesType: Type, nameTable: Set<string>) {
             const type = checkExpression(node.expression);
             const props = getPropertiesOfType(type);
             for (const prop of props) {
                 // Is there a corresponding property in the element attributes type? Skip checking of properties
                 // that have already been assigned to, as these are not actually pushed into the resulting type
-                if (!nameTable[prop.name]) {
+                if (!nameTable.has(prop.name)) {
                     const targetPropSym = getPropertyOfType(elementAttributesType, prop.name);
                     if (targetPropSym) {
                         const msg = chainDiagnosticMessages(undefined, Diagnostics.Property_0_of_JSX_spread_attribute_is_not_assignable_to_target_property, prop.name);
                         checkTypeAssignableTo(getTypeOfSymbol(prop), getTypeOfSymbol(targetPropSym), node, undefined, msg);
                     }
 
-                    nameTable[prop.name] = true;
+                    nameTable.add(prop.name);
                 }
             }
             return type;
         }
 
         function getJsxType(name: string) {
-            if (jsxTypes[name] === undefined) {
-                return jsxTypes[name] = getExportedTypeFromNamespace(JsxNames.JSX, name) || unknownType;
+            const jsxType = jsxTypes.get(name);
+            if (jsxType === undefined) {
+                return setAndReturn(jsxTypes, name, getExportedTypeFromNamespace(JsxNames.JSX, name) || unknownType);
             }
-            return jsxTypes[name];
+            return jsxType;
         }
 
         /**
@@ -10837,7 +10850,7 @@ namespace ts {
 
             const targetAttributesType = getJsxElementAttributesType(node);
 
-            const nameTable = createMap<boolean>();
+            const nameTable = new StringSet();
             // Process this array in right-to-left order so we know which
             // attributes (mostly from spreads) are being overwritten and
             // thus should have their types ignored
@@ -10861,7 +10874,7 @@ namespace ts {
                 const targetProperties = getPropertiesOfType(targetAttributesType);
                 for (let i = 0; i < targetProperties.length; i++) {
                     if (!(targetProperties[i].flags & SymbolFlags.Optional) &&
-                        !nameTable[targetProperties[i].name]) {
+                        !nameTable.has(targetProperties[i].name)) {
 
                         error(node, Diagnostics.Property_0_is_missing_in_type_1, targetProperties[i].name, typeToString(targetAttributesType));
                     }
@@ -11591,7 +11604,7 @@ namespace ts {
             return typeArgumentsAreAssignable;
         }
 
-        function checkApplicableSignature(node: CallLikeExpression, args: Expression[], signature: Signature, relation: Map<RelationComparisonResult>, excludeArgument: boolean[], reportErrors: boolean) {
+        function checkApplicableSignature(node: CallLikeExpression, args: Expression[], signature: Signature, relation: Map<string, RelationComparisonResult>, excludeArgument: boolean[], reportErrors: boolean) {
             const thisType = getThisTypeOfSignature(signature);
             if (thisType && thisType !== voidType && node.kind !== SyntaxKind.NewExpression) {
                 // If the called expression is not of the form `x.f` or `x["f"]`, then sourceType = voidType
@@ -12125,7 +12138,7 @@ namespace ts {
                 diagnostics.add(createDiagnosticForNodeFromMessageChain(node, errorInfo));
             }
 
-            function chooseOverload(candidates: Signature[], relation: Map<RelationComparisonResult>, signatureHelpTrailingComma = false) {
+            function chooseOverload(candidates: Signature[], relation: Map<string, RelationComparisonResult>, signatureHelpTrailingComma = false) {
                 for (const originalCandidate of candidates) {
                     if (!hasCorrectArity(node, args, originalCandidate, signatureHelpTrailingComma)) {
                         continue;
@@ -14271,8 +14284,8 @@ namespace ts {
                 Property = Getter | Setter
             }
 
-            const instanceNames = createMap<Accessor>();
-            const staticNames = createMap<Accessor>();
+            const instanceNames = new StringMap<Accessor>();
+            const staticNames = new StringMap<Accessor>();
             for (const member of node.members) {
                 if (member.kind === SyntaxKind.Constructor) {
                     for (const param of (member as ConstructorDeclaration).parameters) {
@@ -14304,24 +14317,24 @@ namespace ts {
                 }
             }
 
-            function addName(names: Map<Accessor>, location: Node, name: string, meaning: Accessor) {
-                const prev = names[name];
+            function addName(names: Map<string, Accessor>, location: Node, name: string, meaning: Accessor) {
+                const prev = names.get(name);
                 if (prev) {
                     if (prev & meaning) {
                         error(location, Diagnostics.Duplicate_identifier_0, getTextOfNode(location));
                     }
                     else {
-                        names[name] = prev | meaning;
+                        names.set(name, prev | meaning);
                     }
                 }
                 else {
-                    names[name] = meaning;
+                    names.set(name, meaning);
                 }
             }
         }
 
         function checkObjectTypeForDuplicateDeclarations(node: TypeLiteralNode | InterfaceDeclaration) {
-            const names = createMap<boolean>();
+            const names = new StringSet();
             for (const member of node.members) {
                 if (member.kind == SyntaxKind.PropertySignature) {
                     let memberName: string;
@@ -14335,12 +14348,12 @@ namespace ts {
                             continue;
                     }
 
-                    if (names[memberName]) {
+                    if (names.has(memberName)) {
                         error(member.symbol.valueDeclaration.name, Diagnostics.Duplicate_identifier_0, memberName);
                         error(member.name, Diagnostics.Duplicate_identifier_0, memberName);
                     }
                     else {
-                        names[memberName] = true;
+                        names.add(memberName);
                     }
                 }
             }
@@ -15545,8 +15558,7 @@ namespace ts {
 
         function checkUnusedLocalsAndParameters(node: Node): void {
             if (node.parent.kind !== SyntaxKind.InterfaceDeclaration && noUnusedIdentifiers && !isInAmbientContext(node)) {
-                for (const key in node.locals) {
-                    const local = node.locals[key];
+                node.locals.forEach(local => {
                     if (!local.isReferenced) {
                         if (local.valueDeclaration && local.valueDeclaration.kind === SyntaxKind.Parameter) {
                             const parameter = <ParameterDeclaration>local.valueDeclaration;
@@ -15561,7 +15573,7 @@ namespace ts {
                             forEach(local.declarations, d => error(d.name || d, Diagnostics._0_is_declared_but_never_used, local.name));
                         }
                     }
-                }
+                });
             }
         }
 
@@ -15611,8 +15623,7 @@ namespace ts {
 
         function checkUnusedModuleMembers(node: ModuleDeclaration | SourceFile): void {
             if (compilerOptions.noUnusedLocals && !isInAmbientContext(node)) {
-                for (const key in node.locals) {
-                    const local = node.locals[key];
+                node.locals.forEach(local => {
                     if (!local.isReferenced && !local.exportSymbol) {
                         for (const declaration of local.declarations) {
                             if (!isAmbientModule(declaration)) {
@@ -15620,7 +15631,7 @@ namespace ts {
                             }
                         }
                     }
-                }
+                });
             }
         }
 
@@ -16637,7 +16648,7 @@ namespace ts {
                         const identifierName = (<Identifier>catchClause.variableDeclaration.name).text;
                         const locals = catchClause.block.locals;
                         if (locals) {
-                            const localSymbol = locals[identifierName];
+                            const localSymbol = locals.get(identifierName);
                             if (localSymbol && (localSymbol.flags & SymbolFlags.BlockScopedVariable) !== 0) {
                                 grammarErrorOnNode(localSymbol.valueDeclaration, Diagnostics.Cannot_redeclare_identifier_0_in_catch_clause, identifierName);
                             }
@@ -17057,16 +17068,15 @@ namespace ts {
                 return true;
             }
 
-            const seen = createMap<{ prop: Symbol; containingType: Type }>();
-            forEach(resolveDeclaredMembers(type).declaredProperties, p => { seen[p.name] = { prop: p, containingType: type }; });
+            const seen: Map<string, { prop: Symbol; containingType: Type }> = arrayToMap(resolveDeclaredMembers(type).declaredProperties, p => p.name, p => ({ prop: p, containingType: type }));
             let ok = true;
 
             for (const base of baseTypes) {
                 const properties = getPropertiesOfObjectType(getTypeWithThisArgument(base, type.thisType));
                 for (const prop of properties) {
-                    const existing = seen[prop.name];
+                    const existing = seen.get(prop.name);
                     if (!existing) {
-                        seen[prop.name] = { prop: prop, containingType: base };
+                        seen.set(prop.name, { prop, containingType: base });
                     }
                     else {
                         const isInheritedProperty = existing.containingType !== type;
@@ -17804,19 +17814,14 @@ namespace ts {
         }
 
         function hasExportedMembers(moduleSymbol: Symbol) {
-            for (const id in moduleSymbol.exports) {
-                if (id !== "export=") {
-                    return true;
-                }
-            }
-            return false;
+            return someKeyInMap(moduleSymbol.exports, id => id !== "export=");
         }
 
         function checkExternalModuleExports(node: SourceFile | ModuleDeclaration) {
             const moduleSymbol = getSymbolOfNode(node);
             const links = getSymbolLinks(moduleSymbol);
             if (!links.exportsChecked) {
-                const exportEqualsSymbol = moduleSymbol.exports["export="];
+                const exportEqualsSymbol = moduleSymbol.exports.get("export=");
                 if (exportEqualsSymbol && hasExportedMembers(moduleSymbol)) {
                     const declaration = getDeclarationOfAliasSymbol(exportEqualsSymbol) || exportEqualsSymbol.valueDeclaration;
                     if (!isTopLevelInExternalModuleAugmentation(declaration)) {
@@ -17825,21 +17830,20 @@ namespace ts {
                 }
                 // Checks for export * conflicts
                 const exports = getExportsOfModule(moduleSymbol);
-                for (const id in exports) {
+                exports.forEach(({ declarations, flags }, id) => {
                     if (id === "__export") {
-                        continue;
+                        return;
                     }
-                    const { declarations, flags } = exports[id];
                     // ECMA262: 15.2.1.1 It is a Syntax Error if the ExportedNames of ModuleItemList contains any duplicate entries.
                     // (TS Exceptions: namespaces, function overloads, enums, and interfaces)
                     if (flags & (SymbolFlags.Namespace | SymbolFlags.Interface | SymbolFlags.Enum)) {
-                        continue;
+                        return;
                     }
                     const exportedDeclarationsCount = countWhere(declarations, isNotOverload);
                     if (flags & SymbolFlags.TypeAlias && exportedDeclarationsCount <= 2) {
                         // it is legal to merge type alias with other values
                         // so count should be either 1 (just type alias) or 2 (type alias + merged value)
-                        continue;
+                        return;
                     }
                     if (exportedDeclarationsCount > 1) {
                         for (const declaration of declarations) {
@@ -17848,7 +17852,7 @@ namespace ts {
                             }
                         }
                     }
-                }
+                });
                 links.exportsChecked = true;
             }
 
@@ -18123,7 +18127,7 @@ namespace ts {
         }
 
         function getSymbolsInScope(location: Node, meaning: SymbolFlags): Symbol[] {
-            const symbols = createMap<Symbol>();
+            const symbols = new StringMap<Symbol>();
             let memberFlags: ModifierFlags = ModifierFlags.None;
 
             if (isInsideWithStatementBody(location)) {
@@ -18201,18 +18205,17 @@ namespace ts {
                     // We will copy all symbol regardless of its reserved name because
                     // symbolsToArray will check whether the key is a reserved name and
                     // it will not copy symbol with reserved name to the array
-                    if (!symbols[id]) {
-                        symbols[id] = symbol;
+                    if (!symbols.get(id)) {
+                        symbols.set(id, symbol);
                     }
                 }
             }
 
             function copySymbols(source: SymbolTable, meaning: SymbolFlags): void {
                 if (meaning) {
-                    for (const id in source) {
-                        const symbol = source[id];
+                    source.forEach((symbol, id) => {
                         copySymbol(symbol, meaning);
-                    }
+                    });
                 }
             }
         }
@@ -18623,8 +18626,8 @@ namespace ts {
             const propsByName = createSymbolTable(getPropertiesOfType(type));
             if (getSignaturesOfType(type, SignatureKind.Call).length || getSignaturesOfType(type, SignatureKind.Construct).length) {
                 forEach(getPropertiesOfType(globalFunctionType), p => {
-                    if (!propsByName[p.name]) {
-                        propsByName[p.name] = p;
+                    if (!propsByName.get(p.name)) {
+                        propsByName.set(p.name, p);
                     }
                 });
             }
@@ -18687,7 +18690,7 @@ namespace ts {
                 // otherwise - check if at least one export is value
                 symbolLinks.exportsSomeValue = hasExportAssignment
                     ? !!(moduleSymbol.flags & SymbolFlags.Value)
-                    : forEachProperty(getExportsOfModule(moduleSymbol), isValue);
+                    : someValueInMap(getExportsOfModule(moduleSymbol), isValue);
             }
 
             return symbolLinks.exportsSomeValue;
@@ -19037,7 +19040,7 @@ namespace ts {
         }
 
         function hasGlobalName(name: string): boolean {
-            return !!globals[name];
+            return !!globals.get(name);
         }
 
         function getReferencedValueSymbol(reference: Identifier, startInDeclarationContainer?: boolean): Symbol {
@@ -19094,14 +19097,13 @@ namespace ts {
             if (resolvedTypeReferenceDirectives) {
                 // populate reverse mapping: file path -> type reference directive that was resolved to this file
                 fileToDirective = createFileMap<string>();
-                for (const key in resolvedTypeReferenceDirectives) {
-                    const resolvedDirective = resolvedTypeReferenceDirectives[key];
+                resolvedTypeReferenceDirectives.forEach((resolvedDirective, key) => {
                     if (!resolvedDirective) {
-                        continue;
+                        return;
                     }
                     const file = host.getSourceFile(resolvedDirective.resolvedFileName);
                     fileToDirective.set(file.path, key);
-                }
+                });
             }
             return {
                 getReferencedExportContainer,
@@ -19242,11 +19244,9 @@ namespace ts {
                 if (file.symbol && file.symbol.globalExports) {
                     // Merge in UMD exports with first-in-wins semantics (see #9771)
                     const source = file.symbol.globalExports;
-                    for (const id in source) {
-                        if (!(id in globals)) {
-                            globals[id] = source[id];
-                        }
-                    }
+                    source.forEach((sourceSymbol, id) => {
+                        setIfNotSet(globals, id, sourceSymbol);
+                    });
                 }
                 if ((compilerOptions.isolatedModules || isExternalModule(file)) && !file.isDeclarationFile) {
                     const fileRequestedExternalEmitHelpers = file.flags & NodeFlags.EmitHelperFlags;
@@ -19943,7 +19943,7 @@ namespace ts {
         }
 
         function checkGrammarObjectLiteralExpression(node: ObjectLiteralExpression, inDestructuring: boolean) {
-            const seen = createMap<SymbolFlags>();
+            const seen = new StringMap<SymbolFlags>();
             const Property = 1;
             const GetAccessor = 2;
             const SetAccessor = 4;
@@ -20007,17 +20007,17 @@ namespace ts {
                     continue;
                 }
 
-                if (!seen[effectiveName]) {
-                    seen[effectiveName] = currentKind;
+                const existingKind = seen.get(effectiveName);
+                if (!existingKind) {
+                    seen.set(effectiveName, currentKind);
                 }
                 else {
-                    const existingKind = seen[effectiveName];
                     if (currentKind === Property && existingKind === Property) {
                         grammarErrorOnNode(name, Diagnostics.Duplicate_identifier_0, getTextOfNode(name));
                     }
                     else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
                         if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
-                            seen[effectiveName] = currentKind | existingKind;
+                            seen.set(effectiveName, currentKind | existingKind);
                         }
                         else {
                             return grammarErrorOnNode(name, Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
@@ -20031,7 +20031,7 @@ namespace ts {
         }
 
         function checkGrammarJsxElement(node: JsxOpeningLikeElement) {
-            const seen = createMap<boolean>();
+            const seen = new StringSet();
             for (const attr of node.attributes) {
                 if (attr.kind === SyntaxKind.JsxSpreadAttribute) {
                     continue;
@@ -20039,8 +20039,8 @@ namespace ts {
 
                 const jsxAttr = (<JsxAttribute>attr);
                 const name = jsxAttr.name;
-                if (!seen[name.text]) {
-                    seen[name.text] = true;
+                if (!seen.has(name.text)) {
+                    seen.add(name.text);
                 }
                 else {
                     return grammarErrorOnNode(name, Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
@@ -20534,11 +20534,11 @@ namespace ts {
 
         function getAmbientModules(): Symbol[] {
             const result: Symbol[] = [];
-            for (const sym in globals) {
+            globals.forEach((global, sym) => {
                 if (ambientModuleSymbolRegex.test(sym)) {
-                    result.push(globals[sym]);
+                    result.push(global);
                 }
-            }
+            });
             return result;
         }
     }
diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 648447ac26ac4..12e36f7534a7e 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -65,7 +65,7 @@ namespace ts {
         },
         {
             name: "jsx",
-            type: createMap({
+            type: mapOfMapLike({
                 "preserve": JsxEmit.Preserve,
                 "react": JsxEmit.React
             }),
@@ -95,7 +95,7 @@ namespace ts {
         {
             name: "module",
             shortName: "m",
-            type: createMap({
+            type: mapOfMapLike({
                 "none": ModuleKind.None,
                 "commonjs": ModuleKind.CommonJS,
                 "amd": ModuleKind.AMD,
@@ -109,7 +109,7 @@ namespace ts {
         },
         {
             name: "newLine",
-            type: createMap({
+            type: mapOfMapLike({
                 "crlf": NewLineKind.CarriageReturnLineFeed,
                 "lf": NewLineKind.LineFeed
             }),
@@ -258,7 +258,7 @@ namespace ts {
         {
             name: "target",
             shortName: "t",
-            type: createMap({
+            type: mapOfMapLike({
                 "es3": ScriptTarget.ES3,
                 "es5": ScriptTarget.ES5,
                 "es6": ScriptTarget.ES6,
@@ -292,7 +292,7 @@ namespace ts {
         },
         {
             name: "moduleResolution",
-            type: createMap({
+            type: mapOfMapLike({
                 "node": ModuleResolutionKind.NodeJs,
                 "classic": ModuleResolutionKind.Classic,
             }),
@@ -401,7 +401,7 @@ namespace ts {
             type: "list",
             element: {
                 name: "lib",
-                type: createMap({
+                type: mapOfMapLike({
                     // JavaScript only
                     "es5": "lib.es5.d.ts",
                     "es6": "lib.es2015.d.ts",
@@ -473,8 +473,8 @@ namespace ts {
 
     /* @internal */
     export interface OptionNameMap {
-        optionNameMap: Map<CommandLineOption>;
-        shortOptionNames: Map<string>;
+        optionNameMap: Map<string, CommandLineOption>;
+        shortOptionNames: Map<string, string>;
     }
 
     /* @internal */
@@ -493,12 +493,12 @@ namespace ts {
             return optionNameMapCache;
         }
 
-        const optionNameMap = createMap<CommandLineOption>();
-        const shortOptionNames = createMap<string>();
+        const optionNameMap = new StringMap<CommandLineOption>();
+        const shortOptionNames = new StringMap<string>();
         forEach(optionDeclarations, option => {
-            optionNameMap[option.name.toLowerCase()] = option;
+            optionNameMap.set(option.name.toLowerCase(), option);
             if (option.shortName) {
-                shortOptionNames[option.shortName] = option.name;
+                shortOptionNames.set(option.shortName, option.name);
             }
         });
 
@@ -509,18 +509,16 @@ namespace ts {
     /* @internal */
     export function createCompilerDiagnosticForInvalidCustomType(opt: CommandLineOptionOfCustomType): Diagnostic {
         const namesOfType: string[] = [];
-        for (const key in opt.type) {
-            namesOfType.push(` '${key}'`);
-        }
+        forEachKeyInMap(opt.type, key => namesOfType.push(` '${key}'`));
         return createCompilerDiagnostic(Diagnostics.Argument_for_0_option_must_be_Colon_1, `--${opt.name}`, namesOfType);
     }
 
     /* @internal */
     export function parseCustomTypeOption(opt: CommandLineOptionOfCustomType, value: string, errors: Diagnostic[]) {
         const key = trimString((value || "")).toLowerCase();
-        const map = opt.type;
-        if (key in map) {
-            return map[key];
+        const customType = opt.type.get(key);
+        if (customType !== undefined) {
+            return customType;
         }
         else {
             errors.push(createCompilerDiagnosticForInvalidCustomType(opt));
@@ -573,13 +571,13 @@ namespace ts {
                     s = s.slice(s.charCodeAt(1) === CharacterCodes.minus ? 2 : 1).toLowerCase();
 
                     // Try to translate short option names to their full equivalents.
-                    if (s in shortOptionNames) {
-                        s = shortOptionNames[s];
+                    const short = shortOptionNames.get(s);
+                    if (short !== undefined) {
+                        s = short;
                     }
 
-                    if (s in optionNameMap) {
-                        const opt = optionNameMap[s];
-
+                    const opt = optionNameMap.get(s);
+                    if (opt !== undefined) {
                         if (opt.isTSConfigOnly) {
                             errors.push(createCompilerDiagnostic(Diagnostics.Option_0_can_only_be_specified_in_tsconfig_json_file, opt.name));
                         }
@@ -696,7 +694,7 @@ namespace ts {
      * @param fileNames array of filenames to be generated into tsconfig.json
      */
     /* @internal */
-    export function generateTSConfig(options: CompilerOptions, fileNames: string[]): { compilerOptions: Map<CompilerOptionsValue> } {
+    export function generateTSConfig(options: CompilerOptions, fileNames: string[]): { compilerOptions: MapLike<CompilerOptionsValue> } {
         const compilerOptions = extend(options, defaultInitCompilerOptions);
         const configurations: any = {
             compilerOptions: serializeCompilerOptions(compilerOptions)
@@ -708,7 +706,7 @@ namespace ts {
 
         return configurations;
 
-        function getCustomTypeMapOfCommandLineOption(optionDefinition: CommandLineOption): Map<string | number> | undefined {
+        function getCustomTypeMapOfCommandLineOption(optionDefinition: CommandLineOption): Map<string, string | number> | undefined {
             if (optionDefinition.type === "string" || optionDefinition.type === "number" || optionDefinition.type === "boolean") {
                 // this is of a type CommandLineOptionOfPrimitiveType
                 return undefined;
@@ -721,18 +719,17 @@ namespace ts {
             }
         }
 
-        function getNameOfCompilerOptionValue(value: CompilerOptionsValue, customTypeMap: MapLike<string | number>): string | undefined {
+        function getNameOfCompilerOptionValue(value: CompilerOptionsValue, customTypeMap: Map<string, string | number>): string | undefined {
             // There is a typeMap associated with this command-line option so use it to map value back to its name
-            for (const key in customTypeMap) {
-                if (customTypeMap[key] === value) {
+            return findInMap(customTypeMap, (customValue, key) => {
+                if (customValue === value) {
                     return key;
                 }
-            }
-            return undefined;
+            });
         }
 
-        function serializeCompilerOptions(options: CompilerOptions): Map<CompilerOptionsValue> {
-            const result = createMap<CompilerOptionsValue>();
+        function serializeCompilerOptions(options: CompilerOptions): MapLike<CompilerOptionsValue> {
+            const result = new StringMap<CompilerOptionsValue>();
             const optionsNameMap = getOptionNameMap().optionNameMap;
 
             for (const name in options) {
@@ -748,13 +745,13 @@ namespace ts {
                             break;
                         default:
                             const value = options[name];
-                            let optionDefinition = optionsNameMap[name.toLowerCase()];
+                            let optionDefinition = optionsNameMap.get(name.toLowerCase());
                             if (optionDefinition) {
                                 const customTypeMap = getCustomTypeMapOfCommandLineOption(optionDefinition);
                                 if (!customTypeMap) {
                                     // There is no map associated with this compiler option then use the value as-is
                                     // This is the case if the value is expect to be string, number, boolean or list of string
-                                    result[name] = value;
+                                    result.set(name, value);
                                 }
                                 else {
                                     if (optionDefinition.type === "list") {
@@ -762,11 +759,11 @@ namespace ts {
                                         for (const element of value as (string | number)[]) {
                                             convertedValue.push(getNameOfCompilerOptionValue(element, customTypeMap));
                                         }
-                                        result[name] = convertedValue;
+                                        result.set(name, convertedValue);
                                     }
                                     else {
                                         // There is a typeMap associated with this command-line option so use it to map value back to its name
-                                        result[name] = getNameOfCompilerOptionValue(value, customTypeMap);
+                                        result.set(name, getNameOfCompilerOptionValue(value, customTypeMap));
                                     }
                                 }
                             }
@@ -774,7 +771,7 @@ namespace ts {
                     }
                 }
             }
-            return result;
+            return mapLikeOfMap(result);
         }
     }
 
@@ -1001,8 +998,8 @@ namespace ts {
         const optionNameMap = arrayToMap(optionDeclarations, opt => opt.name);
 
         for (const id in jsonOptions) {
-            if (id in optionNameMap) {
-                const opt = optionNameMap[id];
+            const opt = optionNameMap.get(id);
+            if (opt !== undefined) {
                 defaultOptions[opt.name] = convertJsonOption(opt, jsonOptions[id], basePath, errors);
             }
             else {
@@ -1038,8 +1035,9 @@ namespace ts {
 
     function convertJsonOptionOfCustomType(opt: CommandLineOptionOfCustomType, value: string, errors: Diagnostic[]) {
         const key = value.toLowerCase();
-        if (key in opt.type) {
-            return opt.type[key];
+        const val = opt.type.get(key);
+        if (val !== undefined) {
+            return val;
         }
         else {
             errors.push(createCompilerDiagnosticForInvalidCustomType(opt));
@@ -1148,12 +1146,12 @@ namespace ts {
         // Literal file names (provided via the "files" array in tsconfig.json) are stored in a
         // file map with a possibly case insensitive key. We use this map later when when including
         // wildcard paths.
-        const literalFileMap = createMap<string>();
+        const literalFileMap = new StringMap<string>();
 
         // Wildcard paths (provided via the "includes" array in tsconfig.json) are stored in a
         // file map with a possibly case insensitive key. We use this map to store paths matched
         // via wildcard, and to handle extension priority.
-        const wildcardFileMap = createMap<string>();
+        const wildcardFileMap = new StringMap<string>();
 
         if (include) {
             include = validateSpecs(include, errors, /*allowTrailingRecursion*/ false);
@@ -1167,7 +1165,7 @@ namespace ts {
         // file map that marks whether it was a regular wildcard match (with a `*` or `?` token),
         // or a recursive directory. This information is used by filesystem watchers to monitor for
         // new entries in these paths.
-        const wildcardDirectories: Map<WatchDirectoryFlags> = getWildcardDirectories(include, exclude, basePath, host.useCaseSensitiveFileNames);
+        const wildcardDirectories: Map<string, WatchDirectoryFlags> = getWildcardDirectories(include, exclude, basePath, host.useCaseSensitiveFileNames);
 
         // Rather than requery this for each file and filespec, we query the supported extensions
         // once and store it on the expansion context.
@@ -1178,7 +1176,7 @@ namespace ts {
         if (fileNames) {
             for (const fileName of fileNames) {
                 const file = combinePaths(basePath, fileName);
-                literalFileMap[keyMapper(file)] = file;
+                literalFileMap.set(keyMapper(file), file);
             }
         }
 
@@ -1201,18 +1199,17 @@ namespace ts {
                 removeWildcardFilesWithLowerPriorityExtension(file, wildcardFileMap, supportedExtensions, keyMapper);
 
                 const key = keyMapper(file);
-                if (!(key in literalFileMap) && !(key in wildcardFileMap)) {
-                    wildcardFileMap[key] = file;
+                if (!literalFileMap.has(key)) {
+                    setIfNotSet(wildcardFileMap, key, file);
                 }
             }
         }
 
-        const literalFiles = reduceProperties(literalFileMap, addFileToOutput, []);
-        const wildcardFiles = reduceProperties(wildcardFileMap, addFileToOutput, []);
-        wildcardFiles.sort(host.useCaseSensitiveFileNames ? compareStrings : compareStringsCaseInsensitive);
+        const literalFiles = valuesOfMap(literalFileMap);
+        const wildcardFiles = valuesOfMap(wildcardFileMap).sort(host.useCaseSensitiveFileNames ? compareStrings : compareStringsCaseInsensitive);
         return {
             fileNames: literalFiles.concat(wildcardFiles),
-            wildcardDirectories
+            wildcardDirectories: mapLikeOfMap(wildcardDirectories)
         };
     }
 
@@ -1253,7 +1250,7 @@ namespace ts {
         //  /a/b/a?z    - Watch /a/b directly to catch any new file matching a?z
         const rawExcludeRegex = getRegularExpressionForWildcard(exclude, path, "exclude");
         const excludeRegex = rawExcludeRegex && new RegExp(rawExcludeRegex, useCaseSensitiveFileNames ? "" : "i");
-        const wildcardDirectories = createMap<WatchDirectoryFlags>();
+        const wildcardDirectories = new StringMap<WatchDirectoryFlags>();
         if (include !== undefined) {
             const recursiveKeys: string[] = [];
             for (const file of include) {
@@ -1266,9 +1263,9 @@ namespace ts {
                 if (match) {
                     const key = useCaseSensitiveFileNames ? match[0] : match[0].toLowerCase();
                     const flags = watchRecursivePattern.test(name) ? WatchDirectoryFlags.Recursive : WatchDirectoryFlags.None;
-                    const existingFlags = wildcardDirectories[key];
+                    const existingFlags = wildcardDirectories.get(key);
                     if (existingFlags === undefined || existingFlags < flags) {
-                        wildcardDirectories[key] = flags;
+                        wildcardDirectories.set(key, flags);
                         if (flags === WatchDirectoryFlags.Recursive) {
                             recursiveKeys.push(key);
                         }
@@ -1277,13 +1274,13 @@ namespace ts {
             }
 
             // Remove any subpaths under an existing recursively watched directory.
-            for (const key in wildcardDirectories) {
+            forEachKeyInMap(wildcardDirectories, key => {
                 for (const recursiveKey of recursiveKeys) {
                     if (key !== recursiveKey && containsPath(recursiveKey, key, path, !useCaseSensitiveFileNames)) {
-                        delete wildcardDirectories[key];
+                        wildcardDirectories.delete(key);
                     }
                 }
-            }
+            });
         }
 
         return wildcardDirectories;
@@ -1297,13 +1294,13 @@ namespace ts {
      * @param extensionPriority The priority of the extension.
      * @param context The expansion context.
      */
-    function hasFileWithHigherPriorityExtension(file: string, literalFiles: Map<string>, wildcardFiles: Map<string>, extensions: string[], keyMapper: (value: string) => string) {
+    function hasFileWithHigherPriorityExtension(file: string, literalFiles: Map<string, string>, wildcardFiles: Map<string, string>, extensions: string[], keyMapper: (value: string) => string) {
         const extensionPriority = getExtensionPriority(file, extensions);
         const adjustedExtensionPriority = adjustExtensionPriority(extensionPriority);
         for (let i = ExtensionPriority.Highest; i < adjustedExtensionPriority; i++) {
             const higherPriorityExtension = extensions[i];
             const higherPriorityPath = keyMapper(changeExtension(file, higherPriorityExtension));
-            if (higherPriorityPath in literalFiles || higherPriorityPath in wildcardFiles) {
+            if (literalFiles.has(higherPriorityPath) || wildcardFiles.has(higherPriorityPath)) {
                 return true;
             }
         }
@@ -1319,27 +1316,16 @@ namespace ts {
      * @param extensionPriority The priority of the extension.
      * @param context The expansion context.
      */
-    function removeWildcardFilesWithLowerPriorityExtension(file: string, wildcardFiles: Map<string>, extensions: string[], keyMapper: (value: string) => string) {
+    function removeWildcardFilesWithLowerPriorityExtension(file: string, wildcardFiles: Map<string, string>, extensions: string[], keyMapper: (value: string) => string) {
         const extensionPriority = getExtensionPriority(file, extensions);
         const nextExtensionPriority = getNextLowestExtensionPriority(extensionPriority);
         for (let i = nextExtensionPriority; i < extensions.length; i++) {
             const lowerPriorityExtension = extensions[i];
             const lowerPriorityPath = keyMapper(changeExtension(file, lowerPriorityExtension));
-            delete wildcardFiles[lowerPriorityPath];
+            wildcardFiles.delete(lowerPriorityPath);
         }
     }
 
-    /**
-     * Adds a file to an array of files.
-     *
-     * @param output The output array.
-     * @param file The file path.
-     */
-    function addFileToOutput(output: string[], file: string) {
-        output.push(file);
-        return output;
-    }
-
     /**
      * Gets a case sensitive key.
      *
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index e63bcbf8474b4..4a9c8d7f771ee 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -1,4 +1,5 @@
-/// <reference path="types.ts"/>
+/// <reference path="dataStructures.ts" />
+/// <reference path="types.ts"/>
 /// <reference path="performance.ts" />
 
 /* @internal */
@@ -18,28 +19,8 @@ namespace ts {
         True = -1
     }
 
-    const createObject = Object.create;
-
-    export function createMap<T>(template?: MapLike<T>): Map<T> {
-        const map: Map<T> = createObject(null); // tslint:disable-line:no-null-keyword
-
-        // Using 'delete' on an object causes V8 to put the object in dictionary mode.
-        // This disables creation of hidden classes, which are expensive when an object is
-        // constantly changing shape.
-        map["__"] = undefined;
-        delete map["__"];
-
-        // Copies keys/values from template. Note that for..in will not throw if
-        // template is undefined, and instead will just exit the loop.
-        for (const key in template) if (hasOwnProperty.call(template, key)) {
-            map[key] = template[key];
-        }
-
-        return map;
-    }
-
     export function createFileMap<T>(keyMapper?: (key: string) => string): FileMap<T> {
-        let files = createMap<T>();
+        const files = new StringMap<T>();
         return {
             get,
             set,
@@ -51,39 +32,33 @@ namespace ts {
         };
 
         function forEachValueInMap(f: (key: Path, value: T) => void) {
-            for (const key in files) {
-                f(<Path>key, files[key]);
-            }
+            files.forEach((value, key) => f(key as Path, value));
         }
 
-        function getKeys() {
-            const keys: Path[] = [];
-            for (const key in files) {
-                keys.push(<Path>key);
-            }
-            return keys;
+        function getKeys(): Path[] {
+            return keysOfMap(files) as Path[];
         }
 
         // path should already be well-formed so it does not need to be normalized
         function get(path: Path): T {
-            return files[toKey(path)];
+            return files.get(toKey(path));
         }
 
         function set(path: Path, value: T) {
-            files[toKey(path)] = value;
+            files.set(toKey(path), value);
         }
 
         function contains(path: Path) {
-            return toKey(path) in files;
+            return files.has(toKey(path));
         }
 
         function remove(path: Path) {
             const key = toKey(path);
-            delete files[key];
+            files.delete(key);
         }
 
         function clear() {
-            files = createMap<T>();
+            files.clear();
         }
 
         function toKey(path: Path): string {
@@ -586,242 +561,6 @@ namespace ts {
         return initial;
     }
 
-    const hasOwnProperty = Object.prototype.hasOwnProperty;
-
-    /**
-     * Indicates whether a map-like contains an own property with the specified key.
-     *
-     * NOTE: This is intended for use only with MapLike<T> objects. For Map<T> objects, use
-     *       the 'in' operator.
-     *
-     * @param map A map-like.
-     * @param key A property key.
-     */
-    export function hasProperty<T>(map: MapLike<T>, key: string): boolean {
-        return hasOwnProperty.call(map, key);
-    }
-
-    /**
-     * Gets the value of an owned property in a map-like.
-     *
-     * NOTE: This is intended for use only with MapLike<T> objects. For Map<T> objects, use
-     *       an indexer.
-     *
-     * @param map A map-like.
-     * @param key A property key.
-     */
-    export function getProperty<T>(map: MapLike<T>, key: string): T | undefined {
-        return hasOwnProperty.call(map, key) ? map[key] : undefined;
-    }
-
-    /**
-     * Gets the owned, enumerable property keys of a map-like.
-     *
-     * NOTE: This is intended for use with MapLike<T> objects. For Map<T> objects, use
-     *       Object.keys instead as it offers better performance.
-     *
-     * @param map A map-like.
-     */
-    export function getOwnKeys<T>(map: MapLike<T>): string[] {
-        const keys: string[] = [];
-        for (const key in map) if (hasOwnProperty.call(map, key)) {
-            keys.push(key);
-        }
-        return keys;
-    }
-
-    /**
-     * Enumerates the properties of a Map<T>, invoking a callback and returning the first truthy result.
-     *
-     * @param map A map for which properties should be enumerated.
-     * @param callback A callback to invoke for each property.
-     */
-    export function forEachProperty<T, U>(map: Map<T>, callback: (value: T, key: string) => U): U {
-        let result: U;
-        for (const key in map) {
-            if (result = callback(map[key], key)) break;
-        }
-        return result;
-    }
-
-    /**
-     * Returns true if a Map<T> has some matching property.
-     *
-     * @param map A map whose properties should be tested.
-     * @param predicate An optional callback used to test each property.
-     */
-    export function someProperties<T>(map: Map<T>, predicate?: (value: T, key: string) => boolean) {
-        for (const key in map) {
-            if (!predicate || predicate(map[key], key)) return true;
-        }
-        return false;
-    }
-
-    /**
-     * Performs a shallow copy of the properties from a source Map<T> to a target MapLike<T>
-     *
-     * @param source A map from which properties should be copied.
-     * @param target A map to which properties should be copied.
-     */
-    export function copyProperties<T>(source: Map<T>, target: MapLike<T>): void {
-        for (const key in source) {
-            target[key] = source[key];
-        }
-    }
-
-    export function assign<T1 extends MapLike<{}>, T2, T3>(t: T1, arg1: T2, arg2: T3): T1 & T2 & T3;
-    export function assign<T1 extends MapLike<{}>, T2>(t: T1, arg1: T2): T1 & T2;
-    export function assign<T1 extends MapLike<{}>>(t: T1, ...args: any[]): any;
-    export function assign<T1 extends MapLike<{}>>(t: T1, ...args: any[]) {
-        for (const arg of args) {
-            for (const p of getOwnKeys(arg)) {
-                t[p] = arg[p];
-            }
-        }
-        return t;
-    }
-
-    /**
-     * Reduce the properties of a map.
-     *
-     * NOTE: This is intended for use with Map<T> objects. For MapLike<T> objects, use
-     *       reduceOwnProperties instead as it offers better runtime safety.
-     *
-     * @param map The map to reduce
-     * @param callback An aggregation function that is called for each entry in the map
-     * @param initial The initial value for the reduction.
-     */
-    export function reduceProperties<T, U>(map: Map<T>, callback: (aggregate: U, value: T, key: string) => U, initial: U): U {
-        let result = initial;
-        for (const key in map) {
-            result = callback(result, map[key], String(key));
-        }
-        return result;
-    }
-
-    /**
-     * Reduce the properties defined on a map-like (but not from its prototype chain).
-     *
-     * NOTE: This is intended for use with MapLike<T> objects. For Map<T> objects, use
-     *       reduceProperties instead as it offers better performance.
-     *
-     * @param map The map-like to reduce
-     * @param callback An aggregation function that is called for each entry in the map
-     * @param initial The initial value for the reduction.
-     */
-    export function reduceOwnProperties<T, U>(map: MapLike<T>, callback: (aggregate: U, value: T, key: string) => U, initial: U): U {
-        let result = initial;
-        for (const key in map) if (hasOwnProperty.call(map, key)) {
-            result = callback(result, map[key], String(key));
-        }
-        return result;
-    }
-
-    /**
-     * Performs a shallow equality comparison of the contents of two map-likes.
-     *
-     * @param left A map-like whose properties should be compared.
-     * @param right A map-like whose properties should be compared.
-     */
-    export function equalOwnProperties<T>(left: MapLike<T>, right: MapLike<T>, equalityComparer?: (left: T, right: T) => boolean) {
-        if (left === right) return true;
-        if (!left || !right) return false;
-        for (const key in left) if (hasOwnProperty.call(left, key)) {
-            if (!hasOwnProperty.call(right, key) === undefined) return false;
-            if (equalityComparer ? !equalityComparer(left[key], right[key]) : left[key] !== right[key]) return false;
-        }
-        for (const key in right) if (hasOwnProperty.call(right, key)) {
-            if (!hasOwnProperty.call(left, key)) return false;
-        }
-        return true;
-    }
-
-    /**
-     * Creates a map from the elements of an array.
-     *
-     * @param array the array of input elements.
-     * @param makeKey a function that produces a key for a given element.
-     *
-     * This function makes no effort to avoid collisions; if any two elements produce
-     * the same key with the given 'makeKey' function, then the element with the higher
-     * index in the array will be the one associated with the produced key.
-     */
-    export function arrayToMap<T>(array: T[], makeKey: (value: T) => string): Map<T>;
-    export function arrayToMap<T, U>(array: T[], makeKey: (value: T) => string, makeValue: (value: T) => U): Map<U>;
-    export function arrayToMap<T, U>(array: T[], makeKey: (value: T) => string, makeValue?: (value: T) => U): Map<T | U> {
-        const result = createMap<T | U>();
-        for (const value of array) {
-            result[makeKey(value)] = makeValue ? makeValue(value) : value;
-        }
-        return result;
-    }
-
-    export function isEmpty<T>(map: Map<T>) {
-        for (const id in map) {
-            if (hasProperty(map, id)) {
-                return false;
-            }
-        }
-        return true;
-    }
-
-    export function cloneMap<T>(map: Map<T>) {
-        const clone = createMap<T>();
-        copyProperties(map, clone);
-        return clone;
-    }
-
-    export function clone<T>(object: T): T {
-        const result: any = {};
-        for (const id in object) {
-            if (hasOwnProperty.call(object, id)) {
-                result[id] = (<any>object)[id];
-            }
-        }
-        return result;
-    }
-
-    export function extend<T1, T2>(first: T1 , second: T2): T1 & T2 {
-        const result: T1 & T2 = <any>{};
-        for (const id in second) if (hasOwnProperty.call(second, id)) {
-            (result as any)[id] = (second as any)[id];
-        }
-        for (const id in first) if (hasOwnProperty.call(first, id)) {
-            (result as any)[id] = (first as any)[id];
-        }
-        return result;
-    }
-
-    /**
-     * Adds the value to an array of values associated with the key, and returns the array.
-     * Creates the array if it does not already exist.
-     */
-    export function multiMapAdd<V>(map: Map<V[]>, key: string, value: V): V[] {
-        const values = map[key];
-        if (values) {
-            values.push(value);
-            return values;
-        }
-        else {
-            return map[key] = [value];
-        }
-    }
-
-    /**
-     * Removes a value from an array of values associated with the key.
-     * Does not preserve the order of those values.
-     * Does nothing if `key` is not in `map`, or `value` is not in `map[key]`.
-     */
-    export function multiMapRemove<V>(map: Map<V[]>, key: string, value: V): void {
-        const values = map[key];
-        if (values) {
-            unorderedRemoveItem(values, value);
-            if (!values.length) {
-                delete map[key];
-            }
-        }
-    }
-
     /**
      * Tests whether a value is an array.
      */
@@ -912,10 +651,10 @@ namespace ts {
         return text.replace(/{(\d+)}/g, (match, index?) => args[+index + baseIndex]);
     }
 
-    export let localizedDiagnosticMessages: Map<string> = undefined;
+    export let localizedDiagnosticMessages: Map<string, string> = undefined;
 
     export function getLocaleSpecificMessage(message: DiagnosticMessage) {
-        return localizedDiagnosticMessages && localizedDiagnosticMessages[message.key] || message.message;
+        return localizedDiagnosticMessages && localizedDiagnosticMessages.get(message.key) || message.message;
     }
 
     export function createFileDiagnostic(file: SourceFile, start: number, length: number, message: DiagnosticMessage, ...args: any[]): Diagnostic;
diff --git a/src/compiler/dataStructures.ts b/src/compiler/dataStructures.ts
new file mode 100644
index 0000000000000..57874c0f6c1ba
--- /dev/null
+++ b/src/compiler/dataStructures.ts
@@ -0,0 +1,624 @@
+// NumberMap, StringMap, and StringSet shims
+/* @internal */
+namespace ts {
+    // The global Map object. This may not be available, so we must test for it.
+    declare const Map: NumberMapConstructor & StringMapConstructor | undefined;
+    const usingNativeMaps = typeof Map !== "undefined";
+    // tslint:disable-next-line:no-in-operator
+    const fullyFeaturedMaps = usingNativeMaps && "keys" in Map.prototype && "values" in Map.prototype && "entries" in Map.prototype;
+
+    /** Extra Map methods that may not be available, so we must provide fallbacks. */
+    interface FullyFeaturedMap<K, V> extends Map<K, V> {
+        keys(): Iterator<K>;
+        values(): Iterator<V>;
+        entries(): Iterator<[K, V]>;
+    }
+
+    /** Simplified ES6 Iterator interface. */
+    interface Iterator<T> {
+        next(): { value: T, done: false } | { value: never, done: true };
+    }
+
+    export interface NumberMapConstructor {
+        /**
+         * Creates a new Map with number keys.
+         * If `pairs` is provided, each [key, value] pair will be added to the map.
+         */
+        new<K extends number, V>(pairs?: [K, V][]): Map<K, V>;
+    }
+
+    /**
+     * In runtimes without Maps, this is implemented using a sparse array.
+     * This is generic over the key type because it is usually an enum.
+     */
+    export const NumberMap: NumberMapConstructor = usingNativeMaps ? Map : class ShimNumberMap<K extends number, V> implements Map<K, V> {
+        private data: { [key: number]: V } = [];
+
+        constructor(pairs?: [K, V][]) {
+            if (pairs) {
+                for (const [key, value] of pairs) {
+                    this.data[key as number] = value;
+                }
+            }
+        }
+
+        clear() {
+            this.data = [];
+        }
+
+        delete(key: K) {
+            delete this.data[key as number];
+        }
+
+        get(key: K) {
+            return this.data[key as number];
+        }
+
+        has(key: K) {
+            // tslint:disable-next-line:no-in-operator
+            return (key as number) in this.data;
+        }
+
+        set(key: K, value: V) {
+            this.data[key as number] = value;
+        }
+
+        forEach(action: (value: V, key: K) => void) {
+            for (const key in this.data) {
+                action(this.data[key], key as any as K);
+            }
+        }
+    };
+
+    export interface StringMapConstructor {
+        new<T>(): Map<string, T>;
+    }
+    /** In runtimes without Maps, this is implemented using an object. */
+    export const StringMap: StringMapConstructor = usingNativeMaps ? Map : class ShimStringMap<T> implements Map<string, T> {
+        private data = createDictionaryModeObject<T>();
+
+        constructor() {}
+
+        clear() {
+            this.data = createDictionaryModeObject<T>();
+        }
+
+        delete(key: string) {
+            delete this.data[key];
+        }
+
+        get(key: string) {
+            return this.data[key];
+        }
+
+        has(key: string) {
+            // tslint:disable-next-line:no-in-operator
+            return key in this.data;
+        }
+
+        set(key: string, value: T) {
+            this.data[key] = value;
+        }
+
+        forEach(f: (value: T, key: string) => void) {
+            for (const key in this.data) {
+                f(this.data[key], key);
+            }
+        }
+    };
+
+    const createObject = Object.create;
+    function createDictionaryModeObject<T>(): MapLike<T> {
+        const map = createObject(null); // tslint:disable-line:no-null-keyword
+
+        // Using 'delete' on an object causes V8 to put the object in dictionary mode.
+        // This disables creation of hidden classes, which are expensive when an object is
+        // constantly changing shape.
+        map["__"] = undefined;
+        delete map["__"];
+
+        return map;
+    }
+
+    /** Iterates over entries in the map, returning the first output of `getResult` that is not `undefined`. */
+    export const findInMap: <K, V, U>(map: Map<K, V>, getResult: (value: V, key: K) => U | undefined) => U | undefined = fullyFeaturedMaps
+        ? <K, V, U>(map: FullyFeaturedMap<K, V>, f: (value: V, key: K) => U | undefined) => {
+            const iter = map.entries();
+            while (true) {
+                const { value: pair, done } = iter.next();
+                if (done) {
+                    return undefined;
+                }
+                const [key, value] = pair;
+                const result = f(value, key);
+                if (result !== undefined) {
+                    return result;
+                }
+            }
+        }
+        : <K, V, U>(map: Map<K, V>, f: (value: V, key: K) => U | undefined) => {
+            let result: U | undefined;
+            map.forEach((value, key) => {
+                if (result === undefined)
+                    result = f(value, key);
+            });
+            return result;
+        };
+
+    /** Whether `predicate` is true for at least one entry in the map. */
+    export const someInMap: <K, V>(map: Map<K, V>, predicate: (value: V, key: K) => boolean) => boolean = fullyFeaturedMaps
+        ? <K, V>(map: FullyFeaturedMap<K, V>, predicate: (value: V, key: K) => boolean) =>
+            someInIterator(map.entries(), ([key, value]) => predicate(value, key))
+        : <K, V>(map: Map<K, V>, predicate: (value: V, key: K) => boolean) => {
+            let found = false;
+            map.forEach((value, key) => {
+                found = found || predicate(value, key);
+            });
+            return found;
+        };
+
+    /** Whether `predicate` is true for at least one key in the map. */
+    export const someKeyInMap: <K>(map: Map<K, any>, predicate: (key: K) => boolean) => boolean = fullyFeaturedMaps
+        ? <K>(map: FullyFeaturedMap<K, any>, predicate: (key: K) => boolean) => someInIterator(map.keys(), predicate)
+        : <K>(map: Map<K, any>, predicate: (key: K) => boolean) =>
+            someInMap(map, (_value, key) => predicate(key));
+
+    /** Whether `predicate` is true for at least one value in the map. */
+    export const someValueInMap: <T>(map: Map<any, T>, predicate: (value: T) => boolean) => boolean = fullyFeaturedMaps
+        ? <T>(map: FullyFeaturedMap<any, T>, predicate: (value: T) => boolean) =>
+            someInIterator(map.values(), predicate)
+        : someInMap;
+
+    function someInIterator<T>(iterator: Iterator<T>, predicate: (value: T) => boolean): boolean {
+        while (true) {
+            const { value, done } = iterator.next();
+            if (done) {
+                return false;
+            }
+            if (predicate(value)) {
+                return true;
+            }
+        }
+    }
+
+    /**
+     * Equivalent to the ES6 code:
+     * `for (const key of map.keys()) action(key);`
+     */
+    export const forEachKeyInMap: <K>(map: Map<K, any>, action: (key: K) => void) => void = fullyFeaturedMaps
+        ? <K>(map: FullyFeaturedMap<K, any>, f: (key: K) => void) => {
+            const iter: Iterator<K> = map.keys();
+            while (true) {
+                const { value: key, done } = iter.next();
+                if (done) {
+                    return;
+                }
+                f(key);
+            }
+        }
+        : <K>(map: Map<K, any>, action: (key: K) => void) => {
+            map.forEach((_value, key) => action(key));
+        };
+
+    /** Size of a map. */
+    export const mapSize: (map: Map<any, any>) => number = usingNativeMaps
+        ? map => (map as any).size
+        : map => {
+            let size = 0;
+            map.forEach(() => { size++; });
+            return size;
+        };
+
+    /** Convert a Map to a MapLike. */
+    export function mapLikeOfMap<T>(map: Map<string, T>): MapLike<T> {
+        const obj = createDictionaryModeObject<T>();
+        map.forEach((value, key) => {
+            obj[key] = value;
+        });
+        return obj;
+    }
+
+    /** Create a map from a MapLike. This is useful for writing large maps as object literals. */
+    export function mapOfMapLike<T>(object: MapLike<T>): Map<string, T> {
+        const map = new StringMap<T>();
+        // Copies keys/values from template. Note that for..in will not throw if
+        // template is undefined, and instead will just exit the loop.
+        for (const key in object) if (hasProperty(object, key)) {
+            map.set(key, object[key]);
+        }
+        return map;
+    }
+
+    class ShimStringSet implements Set<string> {
+        private data = createDictionaryModeObject<true>();
+
+        constructor() {}
+
+        add(value: string) {
+            this.data[value] = true;
+        }
+
+        clear() {
+            this.data = createDictionaryModeObject<true>();
+        }
+
+        delete(value: string) {
+            delete this.data[value];
+        }
+
+        forEach(action: (value: string) => void) {
+            for (const value in this.data) {
+                action(value);
+            }
+        }
+
+        has(value: string) {
+            // tslint:disable-next-line:no-in-operator
+            return value in this.data;
+        }
+
+        isEmpty() {
+            // tslint:disable-next-line:no-unused-variable
+            for (const _ in this.data) {
+                return false;
+            }
+            return true;
+        }
+    }
+
+    declare const Set: { new(): Set<string> } | undefined;
+    const usingNativeSets = typeof Set !== "undefined";
+
+    /** In runtimes without Sets, this is implemented using an object. */
+    export const StringSet: { new(): Set<string> } = usingNativeSets ? Set : ShimStringSet;
+
+    /** False if there are any values in the set. */
+    export const setIsEmpty: (set: Set<string>) => boolean = usingNativeSets
+        ? set => (set as any).size === 0
+        : (set: ShimStringSet) => set.isEmpty();
+}
+
+// Map utilities
+namespace ts {
+    /** Create a map containing a single entry key -> value. */
+    export function createMapWithEntry<T>(key: string, value: T): Map<string, T> {
+        const map = new StringMap<T>();
+        map.set(key, value);
+        return map;
+    }
+
+    /** Set a value in a map, then return that value. */
+    export function setAndReturn<K, V>(map: Map<K, V>, key: K, value: V): V {
+        map.set(key, value);
+        return value;
+    }
+
+    /** False if there are any entries in the map. */
+    export function mapIsEmpty(map: Map<any, any>): boolean {
+        return !someKeyInMap(map, () => true);
+    }
+
+    /** Create a new copy of a Map. */
+    export function cloneMap<T>(map: Map<string, T>) {
+        const clone = new StringMap<T>();
+        copyMapEntriesFromTo(map, clone);
+        return clone;
+    }
+
+    /**
+     * Performs a shallow copy of the properties from a source Map to a target Map
+     *
+     * @param source A map from which properties should be copied.
+     * @param target A map to which properties should be copied.
+     */
+    export function copyMapEntriesFromTo<K, V>(source: Map<K, V>, target: Map<K, V>): void {
+        source.forEach((value, key) => {
+            target.set(key, value);
+        });
+    }
+
+    /** Equivalent to `Array.from(map.keys())`. */
+    export function keysOfMap<K>(map: Map<K, any>): K[] {
+        const keys: K[] = [];
+        forEachKeyInMap(map, key => { keys.push(key); });
+        return keys;
+    }
+
+    /** Equivalent to `Array.from(map.values())`. */
+    export function valuesOfMap<V>(map: Map<any, V>): V[] {
+        const values: V[] = [];
+        map.forEach((value) => { values.push(value); });
+        return values;
+    }
+
+    /** Return a new map with each key transformed by `getNewKey`. */
+    export function transformKeys<T>(map: Map<string, T>, getNewKey: (key: string) => string): Map<string, T> {
+        const newMap = new StringMap<T>();
+        map.forEach((value, key) => {
+            newMap.set(getNewKey(key), value);
+        });
+        return newMap;
+    }
+
+    /** Replace each value with the result of calling `getNewValue`. */
+    export function updateMapValues<V>(map: Map<any, V>, getNewValue: (value: V) => V): void {
+        map.forEach((value, key) => {
+            map.set(key, getNewValue(value));
+        });
+    }
+
+    /**
+     * Change the value at `key` by applying the given function to it.
+     * If there is no value at `key` then `getNewValue` will be passed `undefined`.
+     */
+    export function modifyValue<K, V>(map: Map<K, V>, key: K, getNewValue: (value: V) => V) {
+        map.set(key, getNewValue(map.get(key)));
+    }
+
+    /**
+     * Get a value in the map, or if not already present, set and return it.
+     * Treats entries set to `undefined` as equivalent to not being set (saving a call to `has`).
+     */
+    export function getOrUpdate<K, V>(map: Map<K, V>, key: K, getValue: (key: K) => V): V {
+        const value = map.get(key);
+        return value !== undefined ? value : setAndReturn(map, key, getValue(key));
+    }
+
+    /** Like `getOrUpdate`, but recognizes `undefined` as having been already set. */
+    export function getOrUpdateAndAllowUndefined<K, V>(map: Map<K, V>, key: K, getValue: (key: K) => V): V {
+        return map.has(key) ? map.get(key) : setAndReturn(map, key, getValue(key));
+    }
+
+    /**
+     * Sets the the value if the key is not already in the map.
+     * Returns whether the value was set.
+     */
+    export function setIfNotSet<K, V>(map: Map<K, V>, key: K, value: V): boolean {
+        const shouldSet = !map.has(key);
+        if (shouldSet) {
+            map.set(key, value);
+        }
+        return shouldSet;
+    }
+
+    /** Deletes an entry from a map and returns it; or returns undefined if the key was not in the map. */
+    export function tryDelete<K, V>(map: Map<K, V>, key: K): V | undefined {
+        const current = map.get(key);
+        if (current !== undefined) {
+            map.delete(key);
+            return current;
+        }
+        else {
+            return undefined;
+        }
+    }
+
+    /**
+     * Creates a map from the elements of an array.
+     *
+     * @param array the array of input elements.
+     * @param makeKey a function that produces a key for a given element.
+     *
+     * This function makes no effort to avoid collisions; if any two elements produce
+     * the same key with the given 'makeKey' function, then the element with the higher
+     * index in the array will be the one associated with the produced key.
+     */
+    export function arrayToMap<T>(array: T[], makeKey: (value: T) => string): Map<string, T>;
+    export function arrayToMap<T, U>(array: T[], makeKey: (value: T) => string, makeValue: (value: T) => U): Map<string, U>;
+    export function arrayToMap<T, U>(array: T[], makeKey: (value: T) => string, makeValue?: (value: T) => U): Map<string, T | U> {
+        const result = new StringMap<T | U>();
+        for (const value of array) {
+            result.set(makeKey(value), makeValue ? makeValue(value) : value);
+        }
+        return result;
+    }
+
+    /**
+     * Adds the value to an array of values associated with the key, and returns the array.
+     * Creates the array if it does not already exist.
+     */
+    export function multiMapAdd<K, V>(map: Map<K, V[]>, key: K, value: V): V[] {
+        const values = map.get(key);
+        if (values) {
+            values.push(value);
+            return values;
+        }
+        else {
+            return setAndReturn(map, key, [value]);
+        }
+    }
+
+    /**
+     * Removes a value from an array of values associated with the key.
+     * Does not preserve the order of those values.
+     * Does nothing if `key` is not in `map`, or `value` is not in `map[key]`.
+     */
+    export function multiMapRemove<K, V>(map: Map<K, V[]>, key: K, value: V): void {
+        const values = map.get(key);
+        if (values) {
+            unorderedRemoveItem(values, value);
+            if (!values.length) {
+                map.delete(key);
+            }
+        }
+    }
+
+    /** True if the maps have the same keys and values. */
+    export function mapsAreEqual<K, V>(left: Map<K, V>, right: Map<K, V>, valuesAreEqual?: (left: V, right: V) => boolean): boolean {
+        if (left === right) return true;
+        if (!left || !right) return false;
+        const someInLeftHasNoMatch = someInMap(left, (leftValue, leftKey) => {
+            if (!right.has(leftKey)) return true;
+            const rightValue = right.get(leftKey);
+            return !(valuesAreEqual ? valuesAreEqual(leftValue, rightValue) : leftValue === rightValue);
+        });
+        if (someInLeftHasNoMatch) return false;
+        const someInRightHasNoMatch = someKeyInMap(right, rightKey => !left.has(rightKey));
+        return !someInRightHasNoMatch;
+    }
+
+    /**
+     * Creates a sorted array of keys.
+     * Sorts keys according to the iteration order they would have if they were in an object, instead of from a Map.
+     * This is so that tests run consistently whether or not we have a Map shim in place.
+     * The difference between Map iteration order and V8 object insertion order is that V8 moves natrual-number-like keys to the front.
+     */
+    export function sortInV8ObjectInsertionOrder<T>(values: T[], toKey: (t: T) => string): T[] {
+        const naturalNumberKeys: T[] = [];
+        const allOtherKeys: T[] = [];
+        for (const value of values) {
+            // "0" looks like a natural but "08" doesn't.
+            const looksLikeNatural = /^(0|([1-9]\d*))$/.test(toKey(value));
+            (looksLikeNatural ? naturalNumberKeys : allOtherKeys).push(value);
+        }
+        function toInt(value: T): number {
+            return parseInt(toKey(value), 10);
+        }
+        naturalNumberKeys.sort((a, b) => toInt(a) - toInt(b));
+        return naturalNumberKeys.concat(allOtherKeys);
+    }
+}
+
+// Set utilities
+/* @internal */
+namespace ts {
+    /** Union of the `getSet` of each element in the array. */
+    export function setAggregate<T>(array: T[], getSet: (t: T) => Set<string>): Set<string> {
+        const result = new StringSet();
+        for (const value of array) {
+            copySetValuesFromTo(getSet(value), result);
+        }
+        return result;
+    }
+
+    /** Adds all values in `source` to `target`. */
+    function copySetValuesFromTo<T>(source: Set<T>, target: Set<T>): void {
+        source.forEach(value => target.add(value));
+    }
+
+    /** Returns the values in `set` satisfying `predicate`. */
+    export function filterSetToArray<T>(set: Set<T>, predicate: (value: T) => boolean): T[] {
+        const result: T[] = [];
+        set.forEach(value => {
+            if (predicate(value)) {
+                result.push(value);
+            }
+        });
+        return result;
+    }
+}
+
+// MapLike utilities
+/* @internal */
+namespace ts {
+    const hasOwnProperty = Object.prototype.hasOwnProperty;
+
+    export function clone<T>(object: T): T {
+        const result: any = {};
+        for (const id in object) {
+            if (hasOwnProperty.call(object, id)) {
+                result[id] = (<any>object)[id];
+            }
+        }
+        return result;
+    }
+
+    /**
+     * Indicates whether a map-like contains an own property with the specified key.
+     *
+     * NOTE: This is intended for use only with MapLike<T> objects. For Map<T> objects, use
+     *       the 'in' operator.
+     *
+     * @param map A map-like.
+     * @param key A property key.
+     */
+    export function hasProperty<T>(map: MapLike<T>, key: string): boolean {
+        return hasOwnProperty.call(map, key);
+    }
+
+    /**
+     * Gets the value of an owned property in a map-like.
+     *
+     * NOTE: This is intended for use only with MapLike<T> objects. For Map<T> objects, use
+     *       an indexer.
+     *
+     * @param map A map-like.
+     * @param key A property key.
+     */
+    export function getProperty<T>(map: MapLike<T>, key: string): T | undefined {
+        return hasOwnProperty.call(map, key) ? map[key] : undefined;
+    }
+
+    /**
+     * Gets the owned, enumerable property keys of a map-like.
+     *
+     * NOTE: This is intended for use with MapLike<T> objects. For Map<T> objects, use
+     *       Object.keys instead as it offers better performance.
+     *
+     * @param map A map-like.
+     */
+    export function getOwnKeys<T>(map: MapLike<T>): string[] {
+        const keys: string[] = [];
+        for (const key in map) if (hasOwnProperty.call(map, key)) {
+            keys.push(key);
+        }
+        return keys;
+    }
+
+    export function assign<T1 extends MapLike<{}>, T2, T3>(t: T1, arg1: T2, arg2: T3): T1 & T2 & T3;
+    export function assign<T1 extends MapLike<{}>, T2>(t: T1, arg1: T2): T1 & T2;
+    export function assign<T1 extends MapLike<{}>>(t: T1, ...args: any[]): any;
+    export function assign<T1 extends MapLike<{}>>(t: T1, ...args: any[]) {
+        for (const arg of args) {
+            for (const p of getOwnKeys(arg)) {
+                t[p] = arg[p];
+            }
+        }
+        return t;
+    }
+
+    /**
+     * Reduce the properties defined on a map-like (but not from its prototype chain).
+     *
+     * @param map The map-like to reduce
+     * @param callback An aggregation function that is called for each entry in the map
+     * @param initial The initial value for the reduction.
+     */
+    export function reduceOwnProperties<T, U>(map: MapLike<T>, callback: (aggregate: U, value: T, key: string) => U, initial: U): U {
+        let result = initial;
+        for (const key in map) if (hasOwnProperty.call(map, key)) {
+            result = callback(result, map[key], String(key));
+        }
+        return result;
+    }
+
+    /**
+     * Performs a shallow equality comparison of the contents of two map-likes.
+     *
+     * @param left A map-like whose properties should be compared.
+     * @param right A map-like whose properties should be compared.
+     */
+    export function equalOwnProperties<T>(left: MapLike<T>, right: MapLike<T>, equalityComparer?: (left: T, right: T) => boolean) {
+        if (left === right) return true;
+        if (!left || !right) return false;
+        for (const key in left) if (hasOwnProperty.call(left, key)) {
+            if (!hasOwnProperty.call(right, key) === undefined) return false;
+            if (equalityComparer ? !equalityComparer(left[key], right[key]) : left[key] !== right[key]) return false;
+        }
+        for (const key in right) if (hasOwnProperty.call(right, key)) {
+            if (!hasOwnProperty.call(left, key)) return false;
+        }
+        return true;
+    }
+
+    export function extend<T1, T2>(first: T1 , second: T2): T1 & T2 {
+        const result: T1 & T2 = <any>{};
+        for (const id in second) if (hasOwnProperty.call(second, id)) {
+            (result as any)[id] = (second as any)[id];
+        }
+        for (const id in first) if (hasOwnProperty.call(first, id)) {
+            (result as any)[id] = (first as any)[id];
+        }
+        return result;
+    }
+}
diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index 4e19aafa4848b..8e55df7fcf3ce 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -59,7 +59,7 @@ namespace ts {
         let resultHasExternalModuleIndicator: boolean;
         let currentText: string;
         let currentLineMap: number[];
-        let currentIdentifiers: Map<string>;
+        let currentIdentifiers: Map<string, string>;
         let isCurrentFileExternalModule: boolean;
         let reportedDeclarationError = false;
         let errorNameNode: DeclarationName;
@@ -75,7 +75,7 @@ namespace ts {
         // and we could be collecting these paths from multiple files into single one with --out option
         let referencesOutput = "";
 
-        let usedTypeDirectiveReferences: Map<string>;
+        let usedTypeDirectiveReferences: Set<string>;
 
         // Emit references corresponding to each file
         const emittedReferencedFiles: SourceFile[] = [];
@@ -156,9 +156,9 @@ namespace ts {
         });
 
         if (usedTypeDirectiveReferences) {
-            for (const directive in usedTypeDirectiveReferences) {
+            usedTypeDirectiveReferences.forEach(directive => {
                 referencesOutput += `/// <reference types="${directive}" />${newLine}`;
-            }
+            });
         }
 
         return {
@@ -267,11 +267,11 @@ namespace ts {
             }
 
             if (!usedTypeDirectiveReferences) {
-                usedTypeDirectiveReferences = createMap<string>();
+                usedTypeDirectiveReferences = new StringSet();
             }
             for (const directive of typeReferenceDirectives) {
-                if (!(directive in usedTypeDirectiveReferences)) {
-                    usedTypeDirectiveReferences[directive] = directive;
+                if (!usedTypeDirectiveReferences.has(directive)) {
+                    usedTypeDirectiveReferences.add(directive);
                 }
             }
         }
@@ -535,14 +535,14 @@ namespace ts {
         // do not need to keep track of created temp names.
         function getExportDefaultTempVariableName(): string {
             const baseName = "_default";
-            if (!(baseName in currentIdentifiers)) {
+            if (!currentIdentifiers.has(baseName)) {
                 return baseName;
             }
             let count = 0;
             while (true) {
                 count++;
                 const name = baseName + "_" + count;
-                if (!(name in currentIdentifiers)) {
+                if (!currentIdentifiers.has(name)) {
                     return name;
                 }
             }
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index b3242e211de92..4881bfcf3ef76 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -219,11 +219,11 @@ const _super = (function (geti, seti) {
 
         let nodeIdToGeneratedName: string[];
         let autoGeneratedIdToGeneratedName: string[];
-        let generatedNameSet: Map<string>;
+        let generatedNameSet: Set<string>;
         let tempFlags: TempFlags;
         let currentSourceFile: SourceFile;
         let currentText: string;
-        let currentFileIdentifiers: Map<string>;
+        let currentFileIdentifiers: Map<string, string>;
         let extendsEmitted: boolean;
         let assignEmitted: boolean;
         let decorateEmitted: boolean;
@@ -292,7 +292,7 @@ const _super = (function (geti, seti) {
             sourceMap.initialize(jsFilePath, sourceMapFilePath, sourceFiles, isBundledEmit);
             nodeIdToGeneratedName = [];
             autoGeneratedIdToGeneratedName = [];
-            generatedNameSet = createMap<string>();
+            generatedNameSet = new StringSet();
             isOwnFileEmit = !isBundledEmit;
 
             // Emit helpers from all the files
@@ -2621,15 +2621,16 @@ const _super = (function (geti, seti) {
 
         function isUniqueName(name: string): boolean {
             return !resolver.hasGlobalName(name) &&
-                !hasProperty(currentFileIdentifiers, name) &&
-                !hasProperty(generatedNameSet, name);
+                !currentFileIdentifiers.has(name) &&
+                !generatedNameSet.has(name);
         }
 
         function isUniqueLocalName(name: string, container: Node): boolean {
             for (let node = container; isNodeDescendantOf(node, container); node = node.nextContainer) {
-                if (node.locals && hasProperty(node.locals, name)) {
+                if (node.locals) {
+                    const local = node.locals.get(name);
                     // We conservatively include alias symbols to cover cases where they're emitted as locals
-                    if (node.locals[name].flags & (SymbolFlags.Value | SymbolFlags.ExportValue | SymbolFlags.Alias)) {
+                    if (local && local.flags & (SymbolFlags.Value | SymbolFlags.ExportValue | SymbolFlags.Alias)) {
                         return false;
                     }
                 }
@@ -2678,7 +2679,8 @@ const _super = (function (geti, seti) {
             while (true) {
                 const generatedName = baseName + i;
                 if (isUniqueName(generatedName)) {
-                    return generatedNameSet[generatedName] = generatedName;
+                    generatedNameSet.add(generatedName);
+                    return generatedName;
                 }
                 i++;
             }
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index d873c3ef87777..93e830fa1f36a 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -2659,9 +2659,9 @@ namespace ts {
         return destEmitNode;
     }
 
-    function mergeTokenSourceMapRanges(sourceRanges: Map<TextRange>, destRanges: Map<TextRange>) {
-        if (!destRanges) destRanges = createMap<TextRange>();
-        copyProperties(sourceRanges, destRanges);
+    function mergeTokenSourceMapRanges(sourceRanges: Map<SyntaxKind, TextRange>, destRanges: Map<SyntaxKind, TextRange>): Map<SyntaxKind, TextRange> {
+        if (!destRanges) destRanges = new NumberMap<SyntaxKind, TextRange>();
+        copyMapEntriesFromTo(sourceRanges, destRanges);
         return destRanges;
     }
 
@@ -2753,8 +2753,8 @@ namespace ts {
      */
     export function setTokenSourceMapRange<T extends Node>(node: T, token: SyntaxKind, range: TextRange) {
         const emitNode = getOrCreateEmitNode(node);
-        const tokenSourceMapRanges = emitNode.tokenSourceMapRanges || (emitNode.tokenSourceMapRanges = createMap<TextRange>());
-        tokenSourceMapRanges[token] = range;
+        const tokenSourceMapRanges = emitNode.tokenSourceMapRanges || (emitNode.tokenSourceMapRanges = new NumberMap<SyntaxKind, TextRange>());
+        tokenSourceMapRanges.set(token, range);
         return node;
     }
 
@@ -2795,7 +2795,7 @@ namespace ts {
     export function getTokenSourceMapRange(node: Node, token: SyntaxKind) {
         const emitNode = node.emitNode;
         const tokenSourceMapRanges = emitNode && emitNode.tokenSourceMapRanges;
-        return tokenSourceMapRanges && tokenSourceMapRanges[token];
+        return tokenSourceMapRanges && tokenSourceMapRanges.get(token);
     }
 
     /**
@@ -2880,10 +2880,8 @@ namespace ts {
      * Here we check if alternative name was provided for a given moduleName and return it if possible.
      */
     function tryRenameExternalModule(moduleName: LiteralExpression, sourceFile: SourceFile) {
-        if (sourceFile.renamedDependencies && hasProperty(sourceFile.renamedDependencies, moduleName.text)) {
-            return createLiteral(sourceFile.renamedDependencies[moduleName.text]);
-        }
-        return undefined;
+        const rename = sourceFile.renamedDependencies && sourceFile.renamedDependencies.get(moduleName.text);
+        return rename && createLiteral(rename);
     }
 
     /**
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 51afa9b0a8943..9ff3f78998420 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -490,7 +490,7 @@ namespace ts {
         let currentToken: SyntaxKind;
         let sourceText: string;
         let nodeCount: number;
-        let identifiers: Map<string>;
+        let identifiers: Map<string, string>;
         let identifierCount: number;
 
         let parsingContext: ParsingContext;
@@ -600,7 +600,7 @@ namespace ts {
 
             parseDiagnostics = [];
             parsingContext = 0;
-            identifiers = createMap<string>();
+            identifiers = new StringMap<string>();
             identifierCount = 0;
             nodeCount = 0;
 
@@ -1101,7 +1101,7 @@ namespace ts {
 
         function internIdentifier(text: string): string {
             text = escapeIdentifier(text);
-            return identifiers[text] || (identifiers[text] = text);
+            return getOrUpdate(identifiers, text, text => text);
         }
 
         // An identifier that starts with two underscores has an extra underscore character prepended to it to avoid issues
diff --git a/src/compiler/performance.ts b/src/compiler/performance.ts
index e8f064e81cdf3..b94386acc87a6 100644
--- a/src/compiler/performance.ts
+++ b/src/compiler/performance.ts
@@ -16,9 +16,9 @@ namespace ts.performance {
 
     let enabled = false;
     let profilerStart = 0;
-    let counts: Map<number>;
-    let marks: Map<number>;
-    let measures: Map<number>;
+    let counts: Map<string, number>;
+    let marks: Map<string, number>;
+    let measures: Map<string, number>;
 
     /**
      * Marks a performance event.
@@ -27,8 +27,8 @@ namespace ts.performance {
      */
     export function mark(markName: string) {
         if (enabled) {
-            marks[markName] = timestamp();
-            counts[markName] = (counts[markName] || 0) + 1;
+            marks.set(markName, timestamp());
+            counts.set(markName, (counts.get(markName) || 0) + 1);
             profilerEvent(markName);
         }
     }
@@ -44,9 +44,9 @@ namespace ts.performance {
      */
     export function measure(measureName: string, startMarkName?: string, endMarkName?: string) {
         if (enabled) {
-            const end = endMarkName && marks[endMarkName] || timestamp();
-            const start = startMarkName && marks[startMarkName] || profilerStart;
-            measures[measureName] = (measures[measureName] || 0) + (end - start);
+            const end = endMarkName && marks.get(endMarkName) || timestamp();
+            const start = startMarkName && marks.get(startMarkName) || profilerStart;
+            measures.set(measureName, (measures.get(measureName) || 0) + (end - start));
         }
     }
 
@@ -56,7 +56,7 @@ namespace ts.performance {
      * @param markName The name of the mark.
      */
     export function getCount(markName: string) {
-        return counts && counts[markName] || 0;
+        return counts && counts.get(markName) || 0;
     }
 
     /**
@@ -65,7 +65,7 @@ namespace ts.performance {
      * @param measureName The name of the measure whose durations should be accumulated.
      */
     export function getDuration(measureName: string) {
-        return measures && measures[measureName] || 0;
+        return measures && measures.get(measureName) || 0;
     }
 
     /**
@@ -74,16 +74,14 @@ namespace ts.performance {
      * @param cb The action to perform for each measure
      */
     export function forEachMeasure(cb: (measureName: string, duration: number) => void) {
-        for (const key in measures) {
-            cb(key, measures[key]);
-        }
+        measures.forEach((duration, measureName) => cb(measureName, duration));
     }
 
     /** Enables (and resets) performance measurements for the compiler. */
     export function enable() {
-        counts = createMap<number>();
-        marks = createMap<number>();
-        measures = createMap<number>();
+        counts = new StringMap<number>();
+        marks = new StringMap<number>();
+        measures = new StringMap<number>();
         enabled = true;
         profilerStart = timestamp();
     }
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index e300ac22fe59e..cdadbe2a259ff 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -82,7 +82,7 @@ namespace ts {
     }
 
     export function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost {
-        const existingDirectories = createMap<boolean>();
+        const existingDirectories = new StringSet();
 
         function getCanonicalFileName(fileName: string): string {
             // if underlying system can distinguish between two files whose names differs only in cases then file name already in canonical form.
@@ -114,11 +114,11 @@ namespace ts {
         }
 
         function directoryExists(directoryPath: string): boolean {
-            if (directoryPath in existingDirectories) {
+            if (existingDirectories.has(directoryPath)) {
                 return true;
             }
             if (sys.directoryExists(directoryPath)) {
-                existingDirectories[directoryPath] = true;
+                existingDirectories.add(directoryPath);
                 return true;
             }
             return false;
@@ -132,21 +132,21 @@ namespace ts {
             }
         }
 
-        let outputFingerprints: Map<OutputFingerprint>;
+        let outputFingerprints: Map<string, OutputFingerprint>;
 
         function writeFileIfUpdated(fileName: string, data: string, writeByteOrderMark: boolean): void {
             if (!outputFingerprints) {
-                outputFingerprints = createMap<OutputFingerprint>();
+                outputFingerprints = new StringMap<OutputFingerprint>();
             }
 
             const hash = sys.createHash(data);
             const mtimeBefore = sys.getModifiedTime(fileName);
 
-            if (mtimeBefore && fileName in outputFingerprints) {
-                const fingerprint = outputFingerprints[fileName];
+            if (mtimeBefore) {
+                const fingerprint = outputFingerprints.get(fileName);
 
                 // If output has not been changed, and the file has no external modification
-                if (fingerprint.byteOrderMark === writeByteOrderMark &&
+                if (fingerprint !== undefined && fingerprint.byteOrderMark === writeByteOrderMark &&
                     fingerprint.hash === hash &&
                     fingerprint.mtime.getTime() === mtimeBefore.getTime()) {
                     return;
@@ -157,11 +157,11 @@ namespace ts {
 
             const mtimeAfter = sys.getModifiedTime(fileName);
 
-            outputFingerprints[fileName] = {
+            outputFingerprints.set(fileName, {
                 hash,
                 byteOrderMark: writeByteOrderMark,
                 mtime: mtimeAfter
-            };
+            });
         }
 
         function writeFile(fileName: string, data: string, writeByteOrderMark: boolean, onError?: (message: string) => void) {
@@ -279,11 +279,11 @@ namespace ts {
             return [];
         }
         const resolutions: T[] = [];
-        const cache = createMap<T>();
+        const cache = new StringMap<T>();
         for (const name of names) {
-            const result = name in cache
-                ? cache[name]
-                : cache[name] = loader(name, containingFile);
+            const result = cache.has(name)
+                ? cache.get(name)
+                : setAndReturn(cache, name, loader(name, containingFile));
             resolutions.push(result);
         }
         return resolutions;
@@ -295,9 +295,9 @@ namespace ts {
         let commonSourceDirectory: string;
         let diagnosticsProducingTypeChecker: TypeChecker;
         let noDiagnosticsTypeChecker: TypeChecker;
-        let classifiableNames: Map<string>;
+        let classifiableNames: Set<string>;
 
-        let resolvedTypeReferenceDirectives = createMap<ResolvedTypeReferenceDirective>();
+        let resolvedTypeReferenceDirectives = new StringMap<ResolvedTypeReferenceDirective>();
         let fileProcessingDiagnostics = createDiagnosticCollection();
 
         // The below settings are to track if a .js file should be add to the program if loaded via searching under node_modules.
@@ -312,10 +312,10 @@ namespace ts {
 
         // If a module has some of its imports skipped due to being at the depth limit under node_modules, then track
         // this, as it may be imported at a shallower depth later, and then it will need its skipped imports processed.
-        const modulesWithElidedImports = createMap<boolean>();
+        const modulesWithElidedImports = new StringMap<boolean>();
 
         // Track source files that are source files found by searching under node_modules, as these shouldn't be compiled.
-        const sourceFilesFoundSearchingNodeModules = createMap<boolean>();
+        const sourceFilesFoundSearchingNodeModules = new StringMap<boolean>();
 
         performance.mark("beforeProgram");
 
@@ -440,15 +440,11 @@ namespace ts {
             return commonSourceDirectory;
         }
 
-        function getClassifiableNames() {
+        function getClassifiableNames(): Set<string> {
             if (!classifiableNames) {
                 // Initialize a checker so that all our files are bound.
                 getTypeChecker();
-                classifiableNames = createMap<string>();
-
-                for (const sourceFile of files) {
-                    copyProperties(sourceFile.classifiableNames, classifiableNames);
-                }
+                classifiableNames = setAggregate(files, sourceFile => sourceFile.classifiableNames);
             }
 
             return classifiableNames;
@@ -598,7 +594,7 @@ namespace ts {
                 getSourceFile: program.getSourceFile,
                 getSourceFileByPath: program.getSourceFileByPath,
                 getSourceFiles: program.getSourceFiles,
-                isSourceFileFromExternalLibrary: (file: SourceFile) => !!sourceFilesFoundSearchingNodeModules[file.path],
+                isSourceFileFromExternalLibrary: (file: SourceFile) => !!sourceFilesFoundSearchingNodeModules.get(file.path),
                 writeFile: writeFileCallback || (
                     (fileName, data, writeByteOrderMark, onError, sourceFiles) => host.writeFile(fileName, data, writeByteOrderMark, onError, sourceFiles)),
                 isEmitBlocked,
@@ -1142,8 +1138,8 @@ namespace ts {
 
         // Get source file from normalized fileName
         function findSourceFile(fileName: string, path: Path, isDefaultLib: boolean, isReference: boolean, refFile?: SourceFile, refPos?: number, refEnd?: number): SourceFile {
-            if (filesByName.contains(path)) {
-                const file = filesByName.get(path);
+            let file = filesByName.get(path);
+            if (file !== undefined) {
                 // try to check if we've already seen this file but with a different casing in path
                 // NOTE: this only makes sense for case-insensitive file systems
                 if (file && options.forceConsistentCasingInFileNames && getNormalizedAbsolutePath(file.fileName, currentDirectory) !== getNormalizedAbsolutePath(fileName, currentDirectory)) {
@@ -1152,20 +1148,20 @@ namespace ts {
 
                 // If the file was previously found via a node_modules search, but is now being processed as a root file,
                 // then everything it sucks in may also be marked incorrectly, and needs to be checked again.
-                if (file && sourceFilesFoundSearchingNodeModules[file.path] && currentNodeModulesDepth == 0) {
-                    sourceFilesFoundSearchingNodeModules[file.path] = false;
+                if (file && sourceFilesFoundSearchingNodeModules.get(file.path) && currentNodeModulesDepth == 0) {
+                    sourceFilesFoundSearchingNodeModules.set(file.path, false);
                     if (!options.noResolve) {
                         processReferencedFiles(file, getDirectoryPath(fileName), isDefaultLib);
                         processTypeReferenceDirectives(file);
                     }
 
-                    modulesWithElidedImports[file.path] = false;
+                    modulesWithElidedImports.set(file.path, false);
                     processImportedModules(file, getDirectoryPath(fileName));
                 }
                 // See if we need to reprocess the imports due to prior skipped imports
-                else if (file && modulesWithElidedImports[file.path]) {
+                else if (file && modulesWithElidedImports.get(file.path)) {
                     if (currentNodeModulesDepth < maxNodeModulesJsDepth) {
-                        modulesWithElidedImports[file.path] = false;
+                        modulesWithElidedImports.set(file.path, false);
                         processImportedModules(file, getDirectoryPath(fileName));
                     }
                 }
@@ -1174,7 +1170,7 @@ namespace ts {
             }
 
             // We haven't looked for this file, do so now and cache result
-            const file = host.getSourceFile(fileName, options.target, hostErrorMessage => {
+            file = host.getSourceFile(fileName, options.target, hostErrorMessage => {
                 if (refFile !== undefined && refPos !== undefined && refEnd !== undefined) {
                     fileProcessingDiagnostics.add(createFileDiagnostic(refFile, refPos, refEnd - refPos,
                         Diagnostics.Cannot_read_file_0_Colon_1, fileName, hostErrorMessage));
@@ -1186,7 +1182,7 @@ namespace ts {
 
             filesByName.set(path, file);
             if (file) {
-                sourceFilesFoundSearchingNodeModules[path] = (currentNodeModulesDepth > 0);
+                sourceFilesFoundSearchingNodeModules.set(path, currentNodeModulesDepth > 0);
                 file.path = path;
 
                 if (host.useCaseSensitiveFileNames()) {
@@ -1248,7 +1244,7 @@ namespace ts {
             refFile?: SourceFile, refPos?: number, refEnd?: number): void {
 
             // If we already found this library as a primary reference - nothing to do
-            const previousResolution = resolvedTypeReferenceDirectives[typeReferenceDirective];
+            const previousResolution = resolvedTypeReferenceDirectives.get(typeReferenceDirective);
             if (previousResolution && previousResolution.primary) {
                 return;
             }
@@ -1285,7 +1281,7 @@ namespace ts {
             }
 
             if (saveResolution) {
-                resolvedTypeReferenceDirectives[typeReferenceDirective] = resolvedTypeReferenceDirective;
+                resolvedTypeReferenceDirectives.set(typeReferenceDirective, resolvedTypeReferenceDirective);
             }
         }
 
@@ -1305,7 +1301,7 @@ namespace ts {
         function processImportedModules(file: SourceFile, basePath: string) {
             collectExternalModuleReferences(file);
             if (file.imports.length || file.moduleAugmentations.length) {
-                file.resolvedModules = createMap<ResolvedModule>();
+                file.resolvedModules = new StringMap<ResolvedModule>();
                 const moduleNames = map(concatenate(file.imports, file.moduleAugmentations), getTextOfLiteral);
                 const resolutions = resolveModuleNamesWorker(moduleNames, getNormalizedAbsolutePath(file.fileName, currentDirectory));
                 for (let i = 0; i < moduleNames.length; i++) {
@@ -1329,7 +1325,7 @@ namespace ts {
                     const shouldAddFile = resolution && !options.noResolve && i < file.imports.length && !elideImport;
 
                     if (elideImport) {
-                        modulesWithElidedImports[file.path] = true;
+                        modulesWithElidedImports.set(file.path, true);
                     }
                     else if (shouldAddFile) {
                         findSourceFile(resolution.resolvedFileName,
diff --git a/src/compiler/scanner.ts b/src/compiler/scanner.ts
index e7b3872f2e3bb..ccf3fa38950d5 100644
--- a/src/compiler/scanner.ts
+++ b/src/compiler/scanner.ts
@@ -56,7 +56,7 @@ namespace ts {
         tryScan<T>(callback: () => T): T;
     }
 
-    const textToToken = createMap({
+    const textToToken = mapOfMapLike({
         "abstract": SyntaxKind.AbstractKeyword,
         "any": SyntaxKind.AnyKeyword,
         "as": SyntaxKind.AsKeyword,
@@ -272,11 +272,11 @@ namespace ts {
             lookupInUnicodeMap(code, unicodeES3IdentifierPart);
     }
 
-    function makeReverseMap(source: Map<number>): string[] {
+    function makeReverseMap(source: Map<string, number>): string[] {
         const result: string[] = [];
-        for (const name in source) {
-            result[source[name]] = name;
-        }
+        source.forEach((num, name) => {
+            result[num] = name;
+        });
         return result;
     }
 
@@ -288,7 +288,7 @@ namespace ts {
 
     /* @internal */
     export function stringToToken(s: string): SyntaxKind {
-        return textToToken[s];
+        return textToToken.get(s);
     }
 
     /* @internal */
@@ -362,8 +362,6 @@ namespace ts {
         return computeLineAndCharacterOfPosition(getLineStarts(sourceFile), position);
     }
 
-    const hasOwnProperty = Object.prototype.hasOwnProperty;
-
     export function isWhiteSpace(ch: number): boolean {
         return isWhiteSpaceSingleLine(ch) || isLineBreak(ch);
     }
@@ -1182,8 +1180,11 @@ namespace ts {
             const len = tokenValue.length;
             if (len >= 2 && len <= 11) {
                 const ch = tokenValue.charCodeAt(0);
-                if (ch >= CharacterCodes.a && ch <= CharacterCodes.z && hasOwnProperty.call(textToToken, tokenValue)) {
-                    return token = textToToken[tokenValue];
+                if (ch >= CharacterCodes.a && ch <= CharacterCodes.z) {
+                    token = textToToken.get(tokenValue);
+                    if (token !== undefined) {
+                        return token;
+                    }
                 }
             }
             return token = SyntaxKind.Identifier;
diff --git a/src/compiler/sourcemap.ts b/src/compiler/sourcemap.ts
index 46db5188e339c..fcf85aa86a676 100644
--- a/src/compiler/sourcemap.ts
+++ b/src/compiler/sourcemap.ts
@@ -362,7 +362,7 @@ namespace ts {
 
             const emitNode = node && node.emitNode;
             const emitFlags = emitNode && emitNode.flags;
-            const range = emitNode && emitNode.tokenSourceMapRanges && emitNode.tokenSourceMapRanges[token];
+            const range = emitNode && emitNode.tokenSourceMapRanges && emitNode.tokenSourceMapRanges.get(token);
 
             tokenPos = skipTrivia(currentSourceText, range ? range.pos : tokenPos);
             if ((emitFlags & EmitFlags.NoTokenLeadingSourceMaps) === 0 && tokenPos >= 0) {
diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index 7cf7d75bc02e2..784c40f4d224d 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -239,25 +239,25 @@ namespace ts {
             const useNonPollingWatchers = process.env["TSC_NONPOLLING_WATCHER"];
 
             function createWatchedFileSet() {
-                const dirWatchers = createMap<DirectoryWatcher>();
+                const dirWatchers = new StringMap<DirectoryWatcher>();
                 // One file can have multiple watchers
-                const fileWatcherCallbacks = createMap<FileWatcherCallback[]>();
+                const fileWatcherCallbacks = new StringMap<FileWatcherCallback[]>();
                 return { addFile, removeFile };
 
                 function reduceDirWatcherRefCountForFile(fileName: string) {
                     const dirName = getDirectoryPath(fileName);
-                    const watcher = dirWatchers[dirName];
+                    const watcher = dirWatchers.get(dirName);
                     if (watcher) {
                         watcher.referenceCount -= 1;
                         if (watcher.referenceCount <= 0) {
                             watcher.close();
-                            delete dirWatchers[dirName];
+                            dirWatchers.delete(dirName);
                         }
                     }
                 }
 
                 function addDirWatcher(dirPath: string): void {
-                    let watcher = dirWatchers[dirPath];
+                    let watcher = dirWatchers.get(dirPath);
                     if (watcher) {
                         watcher.referenceCount += 1;
                         return;
@@ -268,7 +268,7 @@ namespace ts {
                         (eventName: string, relativeFileName: string) => fileEventHandler(eventName, relativeFileName, dirPath)
                     );
                     watcher.referenceCount = 1;
-                    dirWatchers[dirPath] = watcher;
+                    dirWatchers.set(dirPath, watcher);
                     return;
                 }
 
@@ -298,9 +298,12 @@ namespace ts {
                         ? undefined
                         : ts.getNormalizedAbsolutePath(relativeFileName, baseDirPath);
                     // Some applications save a working file via rename operations
-                    if ((eventName === "change" || eventName === "rename") && fileWatcherCallbacks[fileName]) {
-                        for (const fileCallback of fileWatcherCallbacks[fileName]) {
-                            fileCallback(fileName);
+                    if ((eventName === "change" || eventName === "rename")) {
+                        const callbacks = fileWatcherCallbacks.get(fileName);
+                        if (callbacks) {
+                            for (const fileCallback of fileWatcherCallbacks.get(fileName)) {
+                                fileCallback(fileName);
+                           }
                         }
                     }
                 }
diff --git a/src/compiler/transformer.ts b/src/compiler/transformer.ts
index 92407af2bb9fe..e341fd6f69f04 100644
--- a/src/compiler/transformer.ts
+++ b/src/compiler/transformer.ts
@@ -10,14 +10,14 @@
 
 /* @internal */
 namespace ts {
-    const moduleTransformerMap = createMap<Transformer>({
-        [ModuleKind.ES6]: transformES6Module,
-        [ModuleKind.System]: transformSystemModule,
-        [ModuleKind.AMD]: transformModule,
-        [ModuleKind.CommonJS]: transformModule,
-        [ModuleKind.UMD]: transformModule,
-        [ModuleKind.None]: transformModule,
-    });
+    const moduleTransformerMap = new NumberMap<ModuleKind, Transformer>([
+        [ModuleKind.ES6, transformES6Module],
+        [ModuleKind.System, transformSystemModule],
+        [ModuleKind.AMD, transformModule],
+        [ModuleKind.CommonJS, transformModule],
+        [ModuleKind.UMD, transformModule],
+        [ModuleKind.None, transformModule],
+    ]);
 
     const enum SyntaxKindFeatureFlags {
         Substitution = 1 << 0,
@@ -109,7 +109,7 @@ namespace ts {
         const transformers: Transformer[] = [];
 
         transformers.push(transformTypeScript);
-        transformers.push(moduleTransformerMap[moduleKind] || moduleTransformerMap[ModuleKind.None]);
+        transformers.push(moduleTransformerMap.get(moduleKind) || moduleTransformerMap.get(ModuleKind.None));
 
         if (jsx === JsxEmit.React) {
             transformers.push(transformJsx);
@@ -339,4 +339,4 @@ namespace ts {
             return statements;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/compiler/transformers/es6.ts b/src/compiler/transformers/es6.ts
index 7fb0594a6ccba..12ce9d53fd008 100644
--- a/src/compiler/transformers/es6.ts
+++ b/src/compiler/transformers/es6.ts
@@ -70,15 +70,15 @@ namespace ts {
          * set of labels that occurred inside the converted loop
          * used to determine if labeled jump can be emitted as is or it should be dispatched to calling code
          */
-        labels?: Map<string>;
+        labels?: Map<string, string>;
         /*
          * collection of labeled jumps that transfer control outside the converted loop.
          * maps store association 'label -> labelMarker' where
          * - label - value of label as it appear in code
          * - label marker - return value that should be interpreted by calling code as 'jump to <label>'
          */
-        labeledNonLocalBreaks?: Map<string>;
-        labeledNonLocalContinues?: Map<string>;
+        labeledNonLocalBreaks?: Map<string, string>;
+        labeledNonLocalContinues?: Map<string, string>;
 
         /*
          * set of non-labeled jumps that transfer control outside the converted loop
@@ -521,7 +521,7 @@ namespace ts {
                 //   - break/continue is non-labeled and located in non-converted loop/switch statement
                 const jump = node.kind === SyntaxKind.BreakStatement ? Jump.Break : Jump.Continue;
                 const canUseBreakOrContinue =
-                    (node.label && convertedLoopState.labels && convertedLoopState.labels[node.label.text]) ||
+                    (node.label && convertedLoopState.labels && convertedLoopState.labels.get(node.label.text)) ||
                     (!node.label && (convertedLoopState.allowedNonLabeledJumps & jump));
 
                 if (!canUseBreakOrContinue) {
@@ -1849,9 +1849,9 @@ namespace ts {
         function visitLabeledStatement(node: LabeledStatement): VisitResult<Statement> {
             if (convertedLoopState) {
                 if (!convertedLoopState.labels) {
-                    convertedLoopState.labels = createMap<string>();
+                    convertedLoopState.labels = new StringMap<string>();
                 }
-                convertedLoopState.labels[node.label.text] = node.label.text;
+                convertedLoopState.labels.set(node.label.text, node.label.text);
             }
 
             let result: VisitResult<Statement>;
@@ -1863,7 +1863,7 @@ namespace ts {
             }
 
             if (convertedLoopState) {
-                convertedLoopState.labels[node.label.text] = undefined;
+                convertedLoopState.labels.set(node.label.text, undefined);
             }
 
             return result;
@@ -2457,29 +2457,28 @@ namespace ts {
         function setLabeledJump(state: ConvertedLoopState, isBreak: boolean, labelText: string, labelMarker: string): void {
             if (isBreak) {
                 if (!state.labeledNonLocalBreaks) {
-                    state.labeledNonLocalBreaks = createMap<string>();
+                    state.labeledNonLocalBreaks = new StringMap<string>();
                 }
-                state.labeledNonLocalBreaks[labelText] = labelMarker;
+                state.labeledNonLocalBreaks.set(labelText, labelMarker);
             }
             else {
                 if (!state.labeledNonLocalContinues) {
-                    state.labeledNonLocalContinues = createMap<string>();
+                    state.labeledNonLocalContinues = new StringMap<string>();
                 }
-                state.labeledNonLocalContinues[labelText] = labelMarker;
+                state.labeledNonLocalContinues.set(labelText, labelMarker);
             }
         }
 
-        function processLabeledJumps(table: Map<string>, isBreak: boolean, loopResultName: Identifier, outerLoop: ConvertedLoopState, caseClauses: CaseClause[]): void {
+        function processLabeledJumps(table: Map<string, string>, isBreak: boolean, loopResultName: Identifier, outerLoop: ConvertedLoopState, caseClauses: CaseClause[]): void {
             if (!table) {
                 return;
             }
-            for (const labelText in table) {
-                const labelMarker = table[labelText];
+            table.forEach((labelMarker, labelText) => {
                 const statements: Statement[] = [];
                 // if there are no outer converted loop or outer label in question is located inside outer converted loop
                 // then emit labeled break\continue
                 // otherwise propagate pair 'label -> marker' to outer converted loop and emit 'return labelMarker' so outer loop can later decide what to do
-                if (!outerLoop || (outerLoop.labels && outerLoop.labels[labelText])) {
+                if (!outerLoop || (outerLoop.labels && outerLoop.labels.get(labelText))) {
                     const label = createIdentifier(labelText);
                     statements.push(isBreak ? createBreak(label) : createContinue(label));
                 }
@@ -2488,7 +2487,7 @@ namespace ts {
                     statements.push(createReturn(loopResultName));
                 }
                 caseClauses.push(createCaseClause(createLiteral(labelMarker), statements));
-            }
+            });
         }
 
         function processLoopVariableDeclaration(decl: VariableDeclaration | BindingElement, loopParameters: ParameterDeclaration[], loopOutParameters: LoopOutParameter[]) {
diff --git a/src/compiler/transformers/generators.ts b/src/compiler/transformers/generators.ts
index f3a47f037cadd..581ea8438ebb8 100644
--- a/src/compiler/transformers/generators.ts
+++ b/src/compiler/transformers/generators.ts
@@ -217,13 +217,13 @@ namespace ts {
         Endfinally = 7,
     }
 
-    const instructionNames = createMap<string>({
-        [Instruction.Return]: "return",
-        [Instruction.Break]: "break",
-        [Instruction.Yield]: "yield",
-        [Instruction.YieldStar]: "yield*",
-        [Instruction.Endfinally]: "endfinally",
-    });
+    const instructionNames = new NumberMap<Instruction, string>([
+        [Instruction.Return, "return"],
+        [Instruction.Break, "break"],
+        [Instruction.Yield, "yield"],
+        [Instruction.YieldStar, "yield*"],
+        [Instruction.Endfinally, "endfinally"],
+    ]);
 
     export function transformGenerators(context: TransformationContext) {
         const {
@@ -240,8 +240,8 @@ namespace ts {
         context.onSubstituteNode = onSubstituteNode;
 
         let currentSourceFile: SourceFile;
-        let renamedCatchVariables: Map<boolean>;
-        let renamedCatchVariableDeclarations: Map<Identifier>;
+        let renamedCatchVariables: Set<string>;
+        let renamedCatchVariableDeclarations: Map<number, Identifier>;
 
         let inGeneratorFunctionBody: boolean;
         let inStatementContainingYield: boolean;
@@ -1907,12 +1907,12 @@ namespace ts {
         }
 
         function substituteExpressionIdentifier(node: Identifier) {
-            if (renamedCatchVariables && hasProperty(renamedCatchVariables, node.text)) {
+            if (renamedCatchVariables && renamedCatchVariables.has(node.text)) {
                 const original = getOriginalNode(node);
                 if (isIdentifier(original) && original.parent) {
                     const declaration = resolver.getReferencedValueDeclaration(original);
                     if (declaration) {
-                        const name = getProperty(renamedCatchVariableDeclarations, String(getOriginalNodeId(declaration)));
+                        const name = renamedCatchVariableDeclarations.get(getOriginalNodeId(declaration));
                         if (name) {
                             const clone = getMutableClone(name);
                             setSourceMapRange(clone, node);
@@ -2077,13 +2077,13 @@ namespace ts {
             const name = declareLocal(text);
 
             if (!renamedCatchVariables) {
-                renamedCatchVariables = createMap<boolean>();
-                renamedCatchVariableDeclarations = createMap<Identifier>();
+                renamedCatchVariables = new StringSet();
+                renamedCatchVariableDeclarations = new NumberMap<number, Identifier>();
                 context.enableSubstitution(SyntaxKind.Identifier);
             }
 
-            renamedCatchVariables[text] = true;
-            renamedCatchVariableDeclarations[getOriginalNodeId(variable)] = name;
+            renamedCatchVariables.add(text);
+            renamedCatchVariableDeclarations.set(getOriginalNodeId(variable), name);
 
             const exception = <ExceptionBlock>peekBlock();
             Debug.assert(exception.state < ExceptionBlockState.Catch);
@@ -2387,7 +2387,7 @@ namespace ts {
          */
         function createInstruction(instruction: Instruction): NumericLiteral {
             const literal = createLiteral(instruction);
-            literal.trailingComment = instructionNames[instruction];
+            literal.trailingComment = instructionNames.get(instruction);
             return literal;
         }
 
diff --git a/src/compiler/transformers/jsx.ts b/src/compiler/transformers/jsx.ts
index 95a4016bb0aeb..5464325eb5b1e 100644
--- a/src/compiler/transformers/jsx.ts
+++ b/src/compiler/transformers/jsx.ts
@@ -3,7 +3,7 @@
 
 /*@internal*/
 namespace ts {
-    const entities: Map<number> = createEntitiesMap();
+    const entities: Map<string, number> = createEntitiesMap();
 
     export function transformJsx(context: TransformationContext) {
         const compilerOptions = context.getCompilerOptions();
@@ -227,7 +227,7 @@ namespace ts {
                     return String.fromCharCode(parseInt(hex, 16));
                 }
                 else {
-                    const ch = entities[word];
+                    const ch = entities.get(word);
                     // If this is not a valid entity, then just use `match` (replace it with itself, i.e. don't replace)
                     return ch ? String.fromCharCode(ch) : match;
                 }
@@ -275,8 +275,8 @@ namespace ts {
         }
     }
 
-    function createEntitiesMap(): Map<number> {
-        return createMap<number>({
+    function createEntitiesMap(): Map<string, number> {
+        return mapOfMapLike<number>({
             "quot": 0x0022,
             "amp": 0x0026,
             "apos": 0x0027,
diff --git a/src/compiler/transformers/module/module.ts b/src/compiler/transformers/module/module.ts
index c4e9b4c31c802..284dbe852d180 100644
--- a/src/compiler/transformers/module/module.ts
+++ b/src/compiler/transformers/module/module.ts
@@ -4,12 +4,12 @@
 /*@internal*/
 namespace ts {
     export function transformModule(context: TransformationContext) {
-        const transformModuleDelegates = createMap<(node: SourceFile) => SourceFile>({
-            [ModuleKind.None]: transformCommonJSModule,
-            [ModuleKind.CommonJS]: transformCommonJSModule,
-            [ModuleKind.AMD]: transformAMDModule,
-            [ModuleKind.UMD]: transformUMDModule,
-        });
+        const transformModuleDelegates = new NumberMap<ModuleKind, (node: SourceFile) => SourceFile>([
+            [ModuleKind.None, transformCommonJSModule],
+            [ModuleKind.CommonJS, transformCommonJSModule],
+            [ModuleKind.AMD, transformAMDModule],
+            [ModuleKind.UMD, transformUMDModule],
+        ]);
 
         const {
             startLexicalEnvironment,
@@ -35,12 +35,12 @@ namespace ts {
 
         let currentSourceFile: SourceFile;
         let externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[];
-        let exportSpecifiers: Map<ExportSpecifier[]>;
+        let exportSpecifiers: Map<string, ExportSpecifier[]>;
         let exportEquals: ExportAssignment;
-        let bindingNameExportSpecifiersMap: Map<ExportSpecifier[]>;
+        let bindingNameExportSpecifiersMap: Map<string, ExportSpecifier[]>;
         // Subset of exportSpecifiers that is a binding-name.
         // This is to reduce amount of memory we have to keep around even after we done with module-transformer
-        const bindingNameExportSpecifiersForFileMap = createMap<Map<ExportSpecifier[]>>();
+        const bindingNameExportSpecifiersForFileMap = new NumberMap<number, Map<string, ExportSpecifier[]>>();
         let hasExportStarsToExportValues: boolean;
 
         return transformSourceFile;
@@ -62,7 +62,7 @@ namespace ts {
                 ({ externalImports, exportSpecifiers, exportEquals, hasExportStarsToExportValues } = collectExternalModuleInfo(node, resolver));
 
                 // Perform the transformation.
-                const transformModule = transformModuleDelegates[moduleKind] || transformModuleDelegates[ModuleKind.None];
+                const transformModule = transformModuleDelegates.get(moduleKind) || transformModuleDelegates.get(ModuleKind.None);
                 const updated = transformModule(node);
                 aggregateTransformFlags(updated);
 
@@ -524,7 +524,7 @@ namespace ts {
             const original = getOriginalNode(currentSourceFile);
             Debug.assert(original.kind === SyntaxKind.SourceFile);
 
-            if (!original.symbol.exports["___esModule"]) {
+            if (!original.symbol.exports.get("___esModule")) {
                 if (languageVersion === ScriptTarget.ES3) {
                     statements.push(
                         createStatement(
@@ -579,8 +579,9 @@ namespace ts {
         }
 
         function addExportMemberAssignments(statements: Statement[], name: Identifier): void {
-            if (!exportEquals && exportSpecifiers && hasProperty(exportSpecifiers, name.text)) {
-                for (const specifier of exportSpecifiers[name.text]) {
+            const specifiers = !exportEquals && exportSpecifiers && exportSpecifiers.get(name.text);
+            if (specifiers) {
+                for (const specifier of exportSpecifiers.get(name.text)) {
                     statements.push(
                         startOnNewLine(
                             createStatement(
@@ -667,12 +668,11 @@ namespace ts {
                 }
             }
             else {
-                if (!exportEquals && exportSpecifiers && hasProperty(exportSpecifiers, name.text)) {
+                const specifiers = !exportEquals && exportSpecifiers && exportSpecifiers.get(name.text);
+                if (specifiers) {
                     const sourceFileId = getOriginalNodeId(currentSourceFile);
-                    if (!bindingNameExportSpecifiersForFileMap[sourceFileId]) {
-                        bindingNameExportSpecifiersForFileMap[sourceFileId] = createMap<ExportSpecifier[]>();
-                    }
-                    bindingNameExportSpecifiersForFileMap[sourceFileId][name.text] = exportSpecifiers[name.text];
+                    const bindingNameExportSpecifiers = getOrUpdate(bindingNameExportSpecifiersForFileMap, sourceFileId, () => new StringMap());
+                    bindingNameExportSpecifiers.set(name.text, exportSpecifiers.get(name.text));
                     addExportMemberAssignments(resultStatements, name);
                 }
             }
@@ -824,7 +824,7 @@ namespace ts {
 
         function onEmitNode(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void {
             if (node.kind === SyntaxKind.SourceFile) {
-                bindingNameExportSpecifiersMap = bindingNameExportSpecifiersForFileMap[getOriginalNodeId(node)];
+                bindingNameExportSpecifiersMap = bindingNameExportSpecifiersForFileMap.get(getOriginalNodeId(node));
                 previousOnEmitNode(emitContext, node, emitCallback);
                 bindingNameExportSpecifiersMap = undefined;
             }
@@ -890,10 +890,11 @@ namespace ts {
             const left = node.left;
             // If the left-hand-side of the binaryExpression is an identifier and its is export through export Specifier
             if (isIdentifier(left) && isAssignmentOperator(node.operatorToken.kind)) {
-                if (bindingNameExportSpecifiersMap && hasProperty(bindingNameExportSpecifiersMap, left.text)) {
+                const bindingNameExportSpecifiers = bindingNameExportSpecifiersMap && bindingNameExportSpecifiersMap.get(left.text);
+                if (bindingNameExportSpecifiers) {
                     setEmitFlags(node, EmitFlags.NoSubstitution);
                     let nestedExportAssignment: BinaryExpression;
-                    for (const specifier of bindingNameExportSpecifiersMap[left.text]) {
+                    for (const specifier of bindingNameExportSpecifiers) {
                         nestedExportAssignment = nestedExportAssignment ?
                             createExportAssignment(specifier.name, nestedExportAssignment) :
                             createExportAssignment(specifier.name, node);
@@ -910,7 +911,8 @@ namespace ts {
             const operator = node.operator;
             const operand = node.operand;
             if (isIdentifier(operand) && bindingNameExportSpecifiersForFileMap) {
-                if (bindingNameExportSpecifiersMap && hasProperty(bindingNameExportSpecifiersMap, operand.text)) {
+                const bindingNameExportSpecifiers = bindingNameExportSpecifiersMap && bindingNameExportSpecifiersMap.get(operand.text);
+                if (bindingNameExportSpecifiers) {
                     setEmitFlags(node, EmitFlags.NoSubstitution);
                     let transformedUnaryExpression: BinaryExpression;
                     if (node.kind === SyntaxKind.PostfixUnaryExpression) {
@@ -924,7 +926,7 @@ namespace ts {
                         setEmitFlags(transformedUnaryExpression, EmitFlags.NoSubstitution);
                     }
                     let nestedExportAssignment: BinaryExpression;
-                    for (const specifier of bindingNameExportSpecifiersMap[operand.text]) {
+                    for (const specifier of bindingNameExportSpecifiersMap.get(operand.text)) {
                         nestedExportAssignment = nestedExportAssignment ?
                             createExportAssignment(specifier.name, nestedExportAssignment) :
                             createExportAssignment(specifier.name, transformedUnaryExpression || node);
diff --git a/src/compiler/transformers/module/system.ts b/src/compiler/transformers/module/system.ts
index 4a137c89a9336..a160def69412b 100644
--- a/src/compiler/transformers/module/system.ts
+++ b/src/compiler/transformers/module/system.ts
@@ -33,7 +33,7 @@ namespace ts {
         const exportFunctionForFileMap: Identifier[] = [];
         let currentSourceFile: SourceFile;
         let externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[];
-        let exportSpecifiers: Map<ExportSpecifier[]>;
+        let exportSpecifiers: Map<string, ExportSpecifier[]>;
         let exportEquals: ExportAssignment;
         let hasExportStarsToExportValues: boolean;
         let exportFunctionForFile: Identifier;
@@ -273,7 +273,7 @@ namespace ts {
             // this set is used to filter names brought by star expors.
 
             // local names set should only be added if we have anything exported
-            if (!exportedLocalNames && isEmpty(exportSpecifiers)) {
+            if (!exportedLocalNames && mapIsEmpty(exportSpecifiers)) {
                 // no exported declarations (export var ...) or export specifiers (export {x})
                 // check if we have any non star export declarations.
                 let hasExportDeclarationWithExportClause = false;
@@ -1326,20 +1326,20 @@ namespace ts {
         }
 
         function collectDependencyGroups(externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[]) {
-            const groupIndices = createMap<number>();
+            const groupIndices = new StringMap<number>();
             const dependencyGroups: DependencyGroup[] = [];
             for (let i = 0; i < externalImports.length; i++) {
                 const externalImport = externalImports[i];
                 const externalModuleName = getExternalModuleNameLiteral(externalImport, currentSourceFile, host, resolver, compilerOptions);
                 const text = externalModuleName.text;
-                if (hasProperty(groupIndices, text)) {
+                const groupIndex = groupIndices.get(text);
+                if (groupIndex !== undefined) {
                     // deduplicate/group entries in dependency list by the dependency name
-                    const groupIndex = groupIndices[text];
                     dependencyGroups[groupIndex].externalImports.push(externalImport);
                     continue;
                 }
                 else {
-                    groupIndices[text] = dependencyGroups.length;
+                    groupIndices.set(text, dependencyGroups.length);
                     dependencyGroups.push({
                         name: externalModuleName,
                         externalImports: [externalImport]
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 2419ffa4c3b73..56f7dc278ac8f 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -51,7 +51,7 @@ namespace ts {
         let currentNamespace: ModuleDeclaration;
         let currentNamespaceContainerName: Identifier;
         let currentScope: SourceFile | Block | ModuleBlock | CaseBlock;
-        let currentScopeFirstDeclarationsOfName: Map<Node>;
+        let currentScopeFirstDeclarationsOfName: Map<string, Node> | undefined;
         let currentSourceFileExternalHelpersModuleName: Identifier;
 
         /**
@@ -64,7 +64,7 @@ namespace ts {
          * A map that keeps track of aliases created for classes with decorators to avoid issues
          * with the double-binding behavior of classes.
          */
-        let classAliases: Map<Identifier>;
+        let classAliases: Map<number, Identifier>;
 
         /**
          * Keeps track of whether  we are within any containing namespaces when performing
@@ -706,7 +706,7 @@ namespace ts {
             if (resolver.getNodeCheckFlags(node) & NodeCheckFlags.ClassWithConstructorReference) {
                 enableSubstitutionForClassAliases();
                 classAlias = createUniqueName(node.name && !isGeneratedIdentifier(node.name) ? node.name.text : "default");
-                classAliases[getOriginalNodeId(node)] = classAlias;
+                classAliases.set(getOriginalNodeId(node), classAlias);
             }
 
             const declaredName = getDeclarationName(node, /*allowComments*/ true);
@@ -790,7 +790,7 @@ namespace ts {
                 if (resolver.getNodeCheckFlags(node) & NodeCheckFlags.ClassWithConstructorReference) {
                     // record an alias as the class name is not in scope for statics.
                     enableSubstitutionForClassAliases();
-                    classAliases[getOriginalNodeId(node)] = getSynthesizedClone(temp);
+                    classAliases.set(getOriginalNodeId(node), getSynthesizedClone(temp));
                 }
 
                 // To preserve the behavior of the old emitter, we explicitly indent
@@ -2744,12 +2744,10 @@ namespace ts {
             const name = node.symbol && node.symbol.name;
             if (name) {
                 if (!currentScopeFirstDeclarationsOfName) {
-                    currentScopeFirstDeclarationsOfName = createMap<Node>();
+                    currentScopeFirstDeclarationsOfName = new StringMap<Node>();
                 }
 
-                if (!(name in currentScopeFirstDeclarationsOfName)) {
-                    currentScopeFirstDeclarationsOfName[name] = node;
-                }
+                setIfNotSet(currentScopeFirstDeclarationsOfName, name, node);
             }
         }
 
@@ -2761,7 +2759,7 @@ namespace ts {
             if (currentScopeFirstDeclarationsOfName) {
                 const name = node.symbol && node.symbol.name;
                 if (name) {
-                    return currentScopeFirstDeclarationsOfName[name] === node;
+                    return currentScopeFirstDeclarationsOfName.get(name) === node;
                 }
             }
 
@@ -3276,7 +3274,7 @@ namespace ts {
                 context.enableSubstitution(SyntaxKind.Identifier);
 
                 // Keep track of class aliases.
-                classAliases = createMap<Identifier>();
+                classAliases = new NumberMap<number, Identifier>();
             }
         }
 
@@ -3410,7 +3408,7 @@ namespace ts {
                     // constructor references in static property initializers.
                     const declaration = resolver.getReferencedValueDeclaration(node);
                     if (declaration) {
-                        const classAlias = classAliases[declaration.id];
+                        const classAlias = classAliases.get(declaration.id);
                         if (classAlias) {
                             const clone = getSynthesizedClone(classAlias);
                             setSourceMapRange(clone, node);
diff --git a/src/compiler/tsc.ts b/src/compiler/tsc.ts
index b39c017384e16..048e7d8349628 100644
--- a/src/compiler/tsc.ts
+++ b/src/compiler/tsc.ts
@@ -93,7 +93,7 @@ namespace ts {
             return false;
         }
         try {
-            ts.localizedDiagnosticMessages = JSON.parse(fileContents);
+            ts.localizedDiagnosticMessages = mapOfMapLike<string>(JSON.parse(fileContents));
         }
         catch (e) {
             errors.push(createCompilerDiagnostic(Diagnostics.Corrupted_locale_file_0, filePath));
@@ -127,11 +127,11 @@ namespace ts {
     const gutterSeparator = " ";
     const resetEscapeSequence = "\u001b[0m";
     const ellipsis = "...";
-    const categoryFormatMap = createMap<string>({
-        [DiagnosticCategory.Warning]: yellowForegroundEscapeSequence,
-        [DiagnosticCategory.Error]: redForegroundEscapeSequence,
-        [DiagnosticCategory.Message]: blueForegroundEscapeSequence,
-    });
+    const categoryFormatMap = new NumberMap<DiagnosticCategory, string>([
+        [DiagnosticCategory.Warning, yellowForegroundEscapeSequence],
+        [DiagnosticCategory.Error, redForegroundEscapeSequence],
+        [DiagnosticCategory.Message, blueForegroundEscapeSequence],
+    ]);
 
     function formatAndReset(text: string, formatStyle: string) {
         return formatStyle + text + resetEscapeSequence;
@@ -199,7 +199,7 @@ namespace ts {
             output += `${ relativeFileName }(${ firstLine + 1 },${ firstLineChar + 1 }): `;
         }
 
-        const categoryColor = categoryFormatMap[diagnostic.category];
+        const categoryColor = categoryFormatMap.get(diagnostic.category);
         const category = DiagnosticCategory[diagnostic.category].toLowerCase();
         output += `${ formatAndReset(category, categoryColor) } TS${ diagnostic.code }: ${ flattenDiagnosticMessageText(diagnostic.messageText, sys.newLine) }`;
         output += sys.newLine + sys.newLine;
@@ -255,7 +255,7 @@ namespace ts {
 
         // This map stores and reuses results of fileExists check that happen inside 'createProgram'
         // This allows to save time in module resolution heavy scenarios when existence of the same file might be checked multiple times.
-        let cachedExistingFiles: Map<boolean>;
+        let cachedExistingFiles: Map<string, boolean>;
         let hostFileExists: typeof compilerHost.fileExists;
 
         if (commandLine.options.locale) {
@@ -425,7 +425,7 @@ namespace ts {
             }
 
             // reset the cache of existing files
-            cachedExistingFiles = createMap<boolean>();
+            cachedExistingFiles = new StringMap<boolean>();
 
             const compileResult = compile(rootFileNames, compilerOptions, compilerHost);
 
@@ -438,9 +438,7 @@ namespace ts {
         }
 
         function cachedFileExists(fileName: string): boolean {
-            return fileName in cachedExistingFiles
-                ? cachedExistingFiles[fileName]
-                : cachedExistingFiles[fileName] = hostFileExists(fileName);
+            return getOrUpdate(cachedExistingFiles, fileName, hostFileExists);
         }
 
         function getSourceFile(fileName: string, languageVersion: ScriptTarget, onError?: (message: string) => void) {
@@ -700,7 +698,7 @@ namespace ts {
         const usageColumn: string[] = []; // Things like "-d, --declaration" go in here.
         const descriptionColumn: string[] = [];
 
-        const optionsDescriptionMap = createMap<string[]>();  // Map between option.description and list of option.type if it is a kind
+        const optionsDescriptionMap = new StringMap<string[]>();  // Map between option.description and list of option.type if it is a kind
 
         for (let i = 0; i < optsList.length; i++) {
             const option = optsList[i];
@@ -728,11 +726,11 @@ namespace ts {
                 description = getDiagnosticText(option.description);
                 const options: string[] = [];
                 const element = (<CommandLineOptionOfListType>option).element;
-                const typeMap = <Map<number | string>>element.type;
-                for (const key in typeMap) {
+                const typeMap = <Map<string, number | string>>element.type;
+                forEachKeyInMap(typeMap, key => {
                     options.push(`'${key}'`);
-                }
-                optionsDescriptionMap[description] = options;
+                });
+                optionsDescriptionMap.set(description, options);
             }
             else {
                 description = getDiagnosticText(option.description);
@@ -754,7 +752,7 @@ namespace ts {
         for (let i = 0; i < usageColumn.length; i++) {
             const usage = usageColumn[i];
             const description = descriptionColumn[i];
-            const kindsList = optionsDescriptionMap[description];
+            const kindsList = optionsDescriptionMap.get(description);
             output.push(usage + makePadding(marginLength - usage.length + 2) + description + sys.newLine);
 
             if (kindsList) {
diff --git a/src/compiler/tsconfig.json b/src/compiler/tsconfig.json
index f128c994af12b..8dfa32b488486 100644
--- a/src/compiler/tsconfig.json
+++ b/src/compiler/tsconfig.json
@@ -12,6 +12,7 @@
     },
     "files": [
         "core.ts",
+        "dataStructures.ts",
         "performance.ts",
         "sys.ts",
         "types.ts",
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 4a4a25fd62755..3a92904fd7e7d 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -1,11 +1,42 @@
 namespace ts {
-
+    /**
+     * Type of objects whose values are all of the same type.
+     * The `in` and `for-in` operators can *not* be safely used,
+     * since `Object.prototype` may be modified by outside code.
+    */
     export interface MapLike<T> {
         [index: string]: T;
     }
 
-    export interface Map<T> extends MapLike<T> {
-        __mapBrand: any;
+    /**
+     * This contains just the parts of ES6's `Map` interface that we allow.
+     * Map can only be instantiated using NumberMap and StringMap, which come with shims.
+     *
+     * Internet Explorer does not support iterator-returning methods, so those are not allowed here.
+     * But map-using functions in dataStructures.ts check for these features and use them where possible.
+     */
+    export interface Map<K, V> {
+        clear(): void;
+        delete(key: K): void;
+        forEach(action: (value: V, key: K) => void): void;
+        get(key: K): V;
+        /**
+         * Whether the key is in the map.
+         * Note: It is better to ask forgiveness than permission. Consider calling `get` and checking if the result is undefined.
+         */
+        has(key: K): boolean;
+        set(key: K, value: V): void;
+    }
+
+    /**
+     * This contains just the parts of ES6's `Set` interface that we allow.
+     */
+    export interface Set<T> {
+        add(value: T): void;
+        clear(): void;
+        delete(value: T): void;
+        forEach(action: (value: T) => void): void;
+        has(value: T): boolean;
     }
 
     // branded string type used to store absolute, normalized and canonicalized paths
@@ -1757,7 +1788,7 @@ namespace ts {
 
         // this map is used by transpiler to supply alternative names for dependencies (i.e. in case of bundling)
         /* @internal */
-        renamedDependencies?: Map<string>;
+        renamedDependencies?: Map<string, string>;
 
         /**
          * lib.d.ts should have a reference comment like
@@ -1777,7 +1808,7 @@ namespace ts {
         // The first node that causes this file to be a CommonJS module
         /* @internal */ commonJsModuleIndicator: Node;
 
-        /* @internal */ identifiers: Map<string>;
+        /* @internal */ identifiers: Map<string, string>;
         /* @internal */ nodeCount: number;
         /* @internal */ identifierCount: number;
         /* @internal */ symbolCount: number;
@@ -1792,12 +1823,12 @@ namespace ts {
         // Stores a line map for the file.
         // This field should never be used directly to obtain line map, use getLineMap function instead.
         /* @internal */ lineMap: number[];
-        /* @internal */ classifiableNames?: Map<string>;
+        /* @internal */ classifiableNames?: Set<string>;
         // Stores a mapping 'external module reference text' -> 'resolved file name' | undefined
         // It is used to resolve module names in the checker.
         // Content of this field should never be used directly - use getResolvedModuleFileName/setResolvedModuleFileName functions instead
-        /* @internal */ resolvedModules: Map<ResolvedModule>;
-        /* @internal */ resolvedTypeReferenceDirectiveNames: Map<ResolvedTypeReferenceDirective>;
+        /* @internal */ resolvedModules: Map<string, ResolvedModule>;
+        /* @internal */ resolvedTypeReferenceDirectiveNames: Map<string, ResolvedTypeReferenceDirective>;
         /* @internal */ imports: LiteralExpression[];
         /* @internal */ moduleAugmentations: LiteralExpression[];
         /* @internal */ patternAmbientModules?: PatternAmbientModule[];
@@ -1881,7 +1912,7 @@ namespace ts {
         /* @internal */ getDiagnosticsProducingTypeChecker(): TypeChecker;
         /* @internal */ dropDiagnosticsProducingTypeChecker(): void;
 
-        /* @internal */ getClassifiableNames(): Map<string>;
+        /* @internal */ getClassifiableNames(): Set<string>;
 
         /* @internal */ getNodeCount(): number;
         /* @internal */ getIdentifierCount(): number;
@@ -1889,7 +1920,7 @@ namespace ts {
         /* @internal */ getTypeCount(): number;
 
         /* @internal */ getFileProcessingDiagnostics(): DiagnosticCollection;
-        /* @internal */ getResolvedTypeReferenceDirectives(): Map<ResolvedTypeReferenceDirective>;
+        /* @internal */ getResolvedTypeReferenceDirectives(): Map<string, ResolvedTypeReferenceDirective>;
         // For testing purposes only.
         /* @internal */ structureIsReused?: boolean;
     }
@@ -1950,7 +1981,7 @@ namespace ts {
 
         getSourceFiles(): SourceFile[];
         getSourceFile(fileName: string): SourceFile;
-        getResolvedTypeReferenceDirectives(): Map<ResolvedTypeReferenceDirective>;
+        getResolvedTypeReferenceDirectives(): Map<string, ResolvedTypeReferenceDirective>;
     }
 
     export interface TypeChecker {
@@ -2285,7 +2316,7 @@ namespace ts {
         declaredType?: Type;                // Type of class, interface, enum, type alias, or type parameter
         typeParameters?: TypeParameter[];   // Type parameters of type alias (undefined if non-generic)
         inferredClassType?: Type;           // Type of an inferred ES5 class
-        instantiations?: Map<Type>;         // Instantiations of generic type alias (undefined if non-generic)
+        instantiations?: Map<string, Type>;         // Instantiations of generic type alias (undefined if non-generic)
         mapper?: TypeMapper;                // Type mapper for instantiation alias
         referenced?: boolean;               // True if alias symbol has been referenced as a value
         containingType?: UnionOrIntersectionType; // Containing union or intersection type for synthetic property
@@ -2302,7 +2333,7 @@ namespace ts {
     /* @internal */
     export interface TransientSymbol extends Symbol, SymbolLinks { }
 
-    export type SymbolTable = Map<Symbol>;
+    export type SymbolTable = Map<string, Symbol>;
 
     /** Represents a "prefix*suffix" pattern. */
     /* @internal */
@@ -2452,7 +2483,7 @@ namespace ts {
 
     // Enum types (TypeFlags.Enum)
     export interface EnumType extends Type {
-        memberTypes: Map<EnumLiteralType>;
+        memberTypes: Map<number, EnumLiteralType>;
     }
 
     // Enum types (TypeFlags.EnumLiteral)
@@ -2501,7 +2532,7 @@ namespace ts {
     // Generic class and interface types
     export interface GenericType extends InterfaceType, TypeReference {
         /* @internal */
-        instantiations: Map<TypeReference>;   // Generic instantiation cache
+        instantiations: Map<string, TypeReference>;   // Generic instantiation cache
     }
 
     export interface UnionOrIntersectionType extends Type {
@@ -2785,7 +2816,7 @@ namespace ts {
         fileNames: string[];                            // The file names that belong to the same project.
         projectRootPath: string;                        // The path to the project root directory
         safeListPath: string;                           // The path used to retrieve the safe list
-        packageNameToTypingLocation: Map<string>;       // The map of package names to their cached typing locations
+        packageNameToTypingLocation: MapLike<string>;   // The map of package names to their cached typing locations
         typingOptions: TypingOptions;                   // Used to customize the typing inference process
         compilerOptions: CompilerOptions;               // Used as a source for typing inference
     }
@@ -2869,7 +2900,7 @@ namespace ts {
     /* @internal */
     export interface CommandLineOptionBase {
         name: string;
-        type: "string" | "number" | "boolean" | "object" | "list" | Map<number | string>;    // a value of a primitive type, or an object literal mapping named values to actual values
+        type: "string" | "number" | "boolean" | "object" | "list" | Map<string, number | string>;    // a value of a primitive type, or an object literal mapping named values to actual values
         isFilePath?: boolean;                                   // True if option value is a path or fileName
         shortName?: string;                                     // A short mnemonic for convenience - for instance, 'h' can be used in place of 'help'
         description?: DiagnosticMessage;                        // The message describing what the command line switch does
@@ -2885,7 +2916,7 @@ namespace ts {
 
     /* @internal */
     export interface CommandLineOptionOfCustomType extends CommandLineOptionBase {
-        type: Map<number | string>;  // an object literal mapping named values to actual values
+        type: Map<string, number | string>;  // an object literal mapping named values to actual values
     }
 
     /* @internal */
@@ -3178,7 +3209,7 @@ namespace ts {
         flags?: EmitFlags;
         commentRange?: TextRange;
         sourceMapRange?: TextRange;
-        tokenSourceMapRanges?: Map<TextRange>;
+        tokenSourceMapRanges?: Map<SyntaxKind, TextRange>;
         annotatedNodes?: Node[];                // Tracks Parse-tree nodes with EmitNodes for eventual cleanup.
         constantValue?: number;
     }
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 62813e9447c87..bafc0361dc69e 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -103,27 +103,27 @@ namespace ts {
     }
 
     export function hasResolvedModule(sourceFile: SourceFile, moduleNameText: string): boolean {
-        return !!(sourceFile && sourceFile.resolvedModules && sourceFile.resolvedModules[moduleNameText]);
+        return !!(sourceFile && sourceFile.resolvedModules && sourceFile.resolvedModules.get(moduleNameText));
     }
 
     export function getResolvedModule(sourceFile: SourceFile, moduleNameText: string): ResolvedModule {
-        return hasResolvedModule(sourceFile, moduleNameText) ? sourceFile.resolvedModules[moduleNameText] : undefined;
+        return hasResolvedModule(sourceFile, moduleNameText) ? sourceFile.resolvedModules.get(moduleNameText) : undefined;
     }
 
     export function setResolvedModule(sourceFile: SourceFile, moduleNameText: string, resolvedModule: ResolvedModule): void {
         if (!sourceFile.resolvedModules) {
-            sourceFile.resolvedModules = createMap<ResolvedModule>();
+            sourceFile.resolvedModules = new StringMap<ResolvedModule>();
         }
 
-        sourceFile.resolvedModules[moduleNameText] = resolvedModule;
+        sourceFile.resolvedModules.set(moduleNameText, resolvedModule);
     }
 
     export function setResolvedTypeReferenceDirective(sourceFile: SourceFile, typeReferenceDirectiveName: string, resolvedTypeReferenceDirective: ResolvedTypeReferenceDirective): void {
         if (!sourceFile.resolvedTypeReferenceDirectiveNames) {
-            sourceFile.resolvedTypeReferenceDirectiveNames = createMap<ResolvedTypeReferenceDirective>();
+            sourceFile.resolvedTypeReferenceDirectiveNames = new StringMap<ResolvedTypeReferenceDirective>();
         }
 
-        sourceFile.resolvedTypeReferenceDirectiveNames[typeReferenceDirectiveName] = resolvedTypeReferenceDirective;
+        sourceFile.resolvedTypeReferenceDirectiveNames.set(typeReferenceDirectiveName, resolvedTypeReferenceDirective);
     }
 
     /* @internal */
@@ -137,13 +137,13 @@ namespace ts {
     }
 
     /* @internal */
-    export function hasChangesInResolutions<T>(names: string[], newResolutions: T[], oldResolutions: Map<T>, comparer: (oldResolution: T, newResolution: T) => boolean): boolean {
+    export function hasChangesInResolutions<T>(names: string[], newResolutions: T[], oldResolutions: Map<string, T>, comparer: (oldResolution: T, newResolution: T) => boolean): boolean {
         if (names.length !== newResolutions.length) {
             return false;
         }
         for (let i = 0; i < names.length; i++) {
             const newResolution = newResolutions[i];
-            const oldResolution = oldResolutions && oldResolutions[names[i]];
+            const oldResolution = oldResolutions && oldResolutions.get(names[i]);
             const changed =
                 oldResolution
                     ? !newResolution || !comparer(oldResolution, newResolution)
@@ -2207,7 +2207,7 @@ namespace ts {
 
     export function createDiagnosticCollection(): DiagnosticCollection {
         let nonFileDiagnostics: Diagnostic[] = [];
-        const fileDiagnostics = createMap<Diagnostic[]>();
+        const fileDiagnostics = new StringMap<Diagnostic[]>();
 
         let diagnosticsModified = false;
         let modificationCount = 0;
@@ -2225,11 +2225,12 @@ namespace ts {
         }
 
         function reattachFileDiagnostics(newFile: SourceFile): void {
-            if (!hasProperty(fileDiagnostics, newFile.fileName)) {
+            const diagnostics = fileDiagnostics.get(newFile.fileName);
+            if (!diagnostics) {
                 return;
             }
 
-            for (const diagnostic of fileDiagnostics[newFile.fileName]) {
+            for (const diagnostic of diagnostics) {
                 diagnostic.file = newFile;
             }
         }
@@ -2237,10 +2238,10 @@ namespace ts {
         function add(diagnostic: Diagnostic): void {
             let diagnostics: Diagnostic[];
             if (diagnostic.file) {
-                diagnostics = fileDiagnostics[diagnostic.file.fileName];
+                diagnostics = fileDiagnostics.get(diagnostic.file.fileName);
                 if (!diagnostics) {
                     diagnostics = [];
-                    fileDiagnostics[diagnostic.file.fileName] = diagnostics;
+                    fileDiagnostics.set(diagnostic.file.fileName, diagnostics);
                 }
             }
             else {
@@ -2260,7 +2261,7 @@ namespace ts {
         function getDiagnostics(fileName?: string): Diagnostic[] {
             sortAndDeduplicate();
             if (fileName) {
-                return fileDiagnostics[fileName] || [];
+                return fileDiagnostics.get(fileName) || [];
             }
 
             const allDiagnostics: Diagnostic[] = [];
@@ -2270,9 +2271,9 @@ namespace ts {
 
             forEach(nonFileDiagnostics, pushDiagnostic);
 
-            for (const key in fileDiagnostics) {
-                forEach(fileDiagnostics[key], pushDiagnostic);
-            }
+            fileDiagnostics.forEach(diagnostics => {
+                forEach(diagnostics, pushDiagnostic);
+            });
 
             return sortAndDeduplicateDiagnostics(allDiagnostics);
         }
@@ -2285,9 +2286,7 @@ namespace ts {
             diagnosticsModified = false;
             nonFileDiagnostics = sortAndDeduplicateDiagnostics(nonFileDiagnostics);
 
-            for (const key in fileDiagnostics) {
-                fileDiagnostics[key] = sortAndDeduplicateDiagnostics(fileDiagnostics[key]);
-            }
+            updateMapValues(fileDiagnostics, sortAndDeduplicateDiagnostics);
         }
     }
 
@@ -2297,7 +2296,7 @@ namespace ts {
     // the map below must be updated. Note that this regexp *does not* include the 'delete' character.
     // There is no reason for this other than that JSON.stringify does not handle it either.
     const escapedCharsRegExp = /[\\\"\u0000-\u001f\t\v\f\b\r\n\u2028\u2029\u0085]/g;
-    const escapedCharsMap = createMap({
+    const escapedCharsMap = mapOfMapLike({
         "\0": "\\0",
         "\t": "\\t",
         "\v": "\\v",
@@ -2324,7 +2323,7 @@ namespace ts {
         return s;
 
         function getReplacement(c: string) {
-            return escapedCharsMap[c] || get16BitUnicodeEscapeSequence(c.charCodeAt(0));
+            return escapedCharsMap.get(c) || get16BitUnicodeEscapeSequence(c.charCodeAt(0));
         }
     }
 
@@ -3350,18 +3349,19 @@ namespace ts {
         return false;
     }
 
-    const syntaxKindCache = createMap<string>();
+    const syntaxKindCache = new NumberMap<SyntaxKind, string>();
 
     export function formatSyntaxKind(kind: SyntaxKind): string {
         const syntaxKindEnum = (<any>ts).SyntaxKind;
         if (syntaxKindEnum) {
-            if (syntaxKindCache[kind]) {
-                return syntaxKindCache[kind];
+            const cached = syntaxKindCache.get(kind);
+            if (cached !== undefined) {
+                return cached;
             }
 
             for (const name in syntaxKindEnum) {
                 if (syntaxKindEnum[name] === kind) {
-                    return syntaxKindCache[kind] = kind.toString() + " (" + name + ")";
+                    return setAndReturn(syntaxKindCache, kind, `${kind}(${name})`);
                 }
             }
         }
@@ -3498,7 +3498,7 @@ namespace ts {
 
     export function collectExternalModuleInfo(sourceFile: SourceFile, resolver: EmitResolver) {
         const externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[] = [];
-        const exportSpecifiers = createMap<ExportSpecifier[]>();
+        const exportSpecifiers = new StringMap<ExportSpecifier[]>();
         let exportEquals: ExportAssignment = undefined;
         let hasExportStarsToExportValues = false;
         for (const node of sourceFile.statements) {
@@ -3539,7 +3539,7 @@ namespace ts {
                         // export { x, y }
                         for (const specifier of (<ExportDeclaration>node).exportClause.elements) {
                             const name = (specifier.propertyName || specifier.name).text;
-                            (exportSpecifiers[name] || (exportSpecifiers[name] = [])).push(specifier);
+                            multiMapAdd(exportSpecifiers, name, specifier);
                         }
                     }
                     break;
diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index e147eda8535a6..bfb8cb2605eab 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -46,54 +46,54 @@ namespace ts {
      *       supplant the existing `forEachChild` implementation if performance is not
      *       significantly impacted.
      */
-    const nodeEdgeTraversalMap = createMap<NodeTraversalPath>({
-        [SyntaxKind.QualifiedName]: [
+    const nodeEdgeTraversalMap = new NumberMap<SyntaxKind, NodeTraversalPath>([
+        [SyntaxKind.QualifiedName, [
             { name: "left", test: isEntityName },
             { name: "right", test: isIdentifier }
-        ],
-        [SyntaxKind.Decorator]: [
+        ]],
+        [SyntaxKind.Decorator, [
             { name: "expression", test: isLeftHandSideExpression }
-        ],
-        [SyntaxKind.TypeAssertionExpression]: [
+        ]],
+        [SyntaxKind.TypeAssertionExpression, [
             { name: "type", test: isTypeNode },
             { name: "expression", test: isUnaryExpression }
-        ],
-        [SyntaxKind.AsExpression]: [
+        ]],
+        [SyntaxKind.AsExpression, [
             { name: "expression", test: isExpression },
             { name: "type", test: isTypeNode }
-        ],
-        [SyntaxKind.NonNullExpression]: [
+        ]],
+        [SyntaxKind.NonNullExpression, [
             { name: "expression", test: isLeftHandSideExpression }
-        ],
-        [SyntaxKind.EnumDeclaration]: [
+        ]],
+        [SyntaxKind.EnumDeclaration, [
             { name: "decorators", test: isDecorator },
             { name: "modifiers", test: isModifier },
             { name: "name", test: isIdentifier },
             { name: "members", test: isEnumMember }
-        ],
-        [SyntaxKind.ModuleDeclaration]: [
+        ]],
+        [SyntaxKind.ModuleDeclaration, [
             { name: "decorators", test: isDecorator },
             { name: "modifiers", test: isModifier },
             { name: "name", test: isModuleName },
             { name: "body", test: isModuleBody }
-        ],
-        [SyntaxKind.ModuleBlock]: [
+        ]],
+        [SyntaxKind.ModuleBlock, [
             { name: "statements", test: isStatement }
-        ],
-        [SyntaxKind.ImportEqualsDeclaration]: [
+        ]],
+        [SyntaxKind.ImportEqualsDeclaration, [
             { name: "decorators", test: isDecorator },
             { name: "modifiers", test: isModifier },
             { name: "name", test: isIdentifier },
             { name: "moduleReference", test: isModuleReference }
-        ],
-        [SyntaxKind.ExternalModuleReference]: [
+        ]],
+        [SyntaxKind.ExternalModuleReference, [
             { name: "expression", test: isExpression, optional: true }
-        ],
-        [SyntaxKind.EnumMember]: [
+        ]],
+        [SyntaxKind.EnumMember, [
             { name: "name", test: isPropertyName },
             { name: "initializer", test: isExpression, optional: true, parenthesize: parenthesizeExpressionForList }
-        ]
-    });
+        ]]
+    ]);
 
     function reduceNode<T>(node: Node, f: (memo: T, node: Node) => T, initial: T) {
         return node ? f(initial, node) : initial;
@@ -520,7 +520,7 @@ namespace ts {
                 break;
 
             default:
-                const edgeTraversalPath = nodeEdgeTraversalMap[kind];
+                const edgeTraversalPath = nodeEdgeTraversalMap.get(kind);
                 if (edgeTraversalPath) {
                     for (const edge of edgeTraversalPath) {
                         const value = (<MapLike<any>>node)[edge.name];
@@ -1141,10 +1141,10 @@ namespace ts {
 
             default:
                 let updated: Node & MapLike<any>;
-                const edgeTraversalPath = nodeEdgeTraversalMap[kind];
+                const edgeTraversalPath = nodeEdgeTraversalMap.get(kind);
                 if (edgeTraversalPath) {
                     for (const edge of edgeTraversalPath) {
-                        const value = <Node | NodeArray<Node>>(<Node & Map<any>>node)[edge.name];
+                        const value = <Node | NodeArray<Node>>(<Node & MapLike<any>>node)[edge.name];
                         if (value !== undefined) {
                             const visited = isArray(value)
                                 ? visitNodes(value, visitor, edge.test, 0, value.length, edge.parenthesize, node)
diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index 49f834963ee1e..7f6c1f47cbf38 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -99,7 +99,7 @@ namespace FourSlash {
 
     export import IndentStyle = ts.IndentStyle;
 
-    const entityMap = ts.createMap({
+    const entityMap = ts.mapOfMapLike({
         "&": "&amp;",
         "\"": "&quot;",
         "'": "&#39;",
@@ -109,7 +109,7 @@ namespace FourSlash {
     });
 
     export function escapeXmlAttributeValue(s: string) {
-        return s.replace(/[&<>"'\/]/g, ch => entityMap[ch]);
+        return s.replace(/[&<>"'\/]/g, ch => entityMap.get(ch));
     }
 
     // Name of testcase metadata including ts.CompilerOptions properties that will be used by globalOptions
@@ -208,7 +208,7 @@ namespace FourSlash {
 
         public formatCodeSettings: ts.FormatCodeSettings;
 
-        private inputFiles = ts.createMap<string>();  // Map between inputFile's fileName and its content for easily looking up when resolving references
+        private inputFiles = new ts.StringMap<string>();  // Map between inputFile's fileName and its content for easily looking up when resolving references
 
         private static getDisplayPartsJson(displayParts: ts.SymbolDisplayPart[]) {
             let result = "";
@@ -241,7 +241,7 @@ namespace FourSlash {
             }
 
             function tryAdd(path: string) {
-                const inputFile = inputFiles[path];
+                const inputFile = inputFiles.get(path);
                 if (inputFile && !Harness.isDefaultLibraryFile(path)) {
                     languageServiceAdapterHost.addScript(path, inputFile, /*isRootFile*/ true);
                     return true;
@@ -275,7 +275,7 @@ namespace FourSlash {
 
             ts.forEach(testData.files, file => {
                 // Create map between fileName and its content for easily looking up when resolveReference flag is specified
-                this.inputFiles[file.fileName] = file.content;
+                this.inputFiles.set(file.fileName, file.content);
 
                 if (ts.getBaseFileName(file.fileName).toLowerCase() === "tsconfig.json") {
                     const configJson = ts.parseConfigFileTextToJson(file.fileName, file.content);
@@ -341,11 +341,11 @@ namespace FourSlash {
             }
             else {
                 // resolveReference file-option is not specified then do not resolve any files and include all inputFiles
-                for (const fileName in this.inputFiles) {
+                this.inputFiles.forEach((inputFile, fileName) => {
                     if (!Harness.isDefaultLibraryFile(fileName)) {
-                        this.languageServiceAdapterHost.addScript(fileName, this.inputFiles[fileName], /*isRootFile*/ true);
+                        this.languageServiceAdapterHost.addScript(fileName, inputFile, /*isRootFile*/ true);
                     }
-                }
+                });
                 this.languageServiceAdapterHost.addScript(Harness.Compiler.defaultLibFileName,
                     Harness.Compiler.getDefaultLibrarySourceFile().text, /*isRootFile*/ false);
             }
@@ -697,13 +697,10 @@ namespace FourSlash {
 
         public noItemsWithSameNameButDifferentKind(): void {
             const completions = this.getCompletionListAtCaret();
-            const uniqueItems = ts.createMap<string>();
+            const uniqueItems = new ts.StringMap<string>();
             for (const item of completions.entries) {
-                if (!(item.name in uniqueItems)) {
-                    uniqueItems[item.name] = item.kind;
-                }
-                else {
-                    assert.equal(item.kind, uniqueItems[item.name], `Items should have the same kind, got ${item.kind} and ${uniqueItems[item.name]}`);
+                if (!ts.setIfNotSet(uniqueItems, item.name, item.kind)) {
+                    assert.equal(item.kind, uniqueItems.get(item.name), `Items should have the same kind, got ${item.kind} and ${uniqueItems.get(item.name)}`);
                 }
             }
         }
@@ -895,7 +892,7 @@ namespace FourSlash {
         }
 
         public verifyRangesWithSameTextReferenceEachOther() {
-            ts.forEachProperty(this.rangesByText(), ranges => this.verifyRangesReferenceEachOther(ranges));
+            this.rangesByTextMap().forEach(ranges => this.verifyRangesReferenceEachOther(ranges));
         }
 
         public verifyDisplayPartsOfReferencedSymbol(expected: ts.SymbolDisplayPart[]) {
@@ -972,7 +969,8 @@ namespace FourSlash {
         }
 
         public verifyQuickInfos(namesAndTexts: { [name: string]: string | [string, string] }) {
-            ts.forEachProperty(ts.createMap(namesAndTexts), (text, name) => {
+            for (const name in namesAndTexts) {
+                const text = namesAndTexts[name];
                 if (text instanceof Array) {
                     assert(text.length === 2);
                     const [expectedText, expectedDocumentation] = text;
@@ -981,7 +979,7 @@ namespace FourSlash {
                 else {
                     this.verifyQuickInfoAt(name, text);
                 }
-            });
+            }
         }
 
         public verifyQuickInfoString(expectedText: string, expectedDocumentation?: string) {
@@ -1818,8 +1816,8 @@ namespace FourSlash {
             return this.testData.ranges;
         }
 
-        public rangesByText(): ts.Map<Range[]> {
-            const result = ts.createMap<Range[]>();
+        private rangesByTextMap(): ts.Map<string, Range[]> {
+            const result = new ts.StringMap<Range[]>();
             for (const range of this.getRanges()) {
                 const text = this.rangeText(range);
                 ts.multiMapAdd(result, text, range);
@@ -1827,6 +1825,10 @@ namespace FourSlash {
             return result;
         }
 
+        public rangesByText(): ts.MapLike<Range[]> {
+            return ts.mapLikeOfMap(this.rangesByTextMap());
+        }
+
         private rangeText({fileName, start, end}: Range, more = false): string {
             return this.getFileContent(fileName).slice(start, end);
         }
@@ -2073,7 +2075,7 @@ namespace FourSlash {
 
         public verifyBraceCompletionAtPosition(negative: boolean, openingBrace: string) {
 
-            const openBraceMap = ts.createMap<ts.CharacterCodes>({
+            const openBraceMap = ts.mapOfMapLike<ts.CharacterCodes>({
                 "(": ts.CharacterCodes.openParen,
                 "{": ts.CharacterCodes.openBrace,
                 "[": ts.CharacterCodes.openBracket,
@@ -2083,7 +2085,7 @@ namespace FourSlash {
                 "<": ts.CharacterCodes.lessThan
             });
 
-            const charCode = openBraceMap[openingBrace];
+            const charCode = openBraceMap.get(openingBrace);
 
             if (!charCode) {
                 this.raiseError(`Invalid openingBrace '${openingBrace}' specified.`);
@@ -2950,7 +2952,7 @@ namespace FourSlashInterface {
             return this.state.getRanges();
         }
 
-        public rangesByText(): ts.Map<FourSlash.Range[]> {
+        public rangesByText(): ts.MapLike<FourSlash.Range[]> {
             return this.state.rangesByText();
         }
 
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index 7c82aeece788c..7f471ba2b19e6 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -925,19 +925,18 @@ namespace Harness {
         export const defaultLibFileName = "lib.d.ts";
         export const es2015DefaultLibFileName = "lib.es2015.d.ts";
 
-        const libFileNameSourceFileMap = ts.createMap<ts.SourceFile>({
-            [defaultLibFileName]: createSourceFileAndAssertInvariants(defaultLibFileName, IO.readFile(libFolder + "lib.es5.d.ts"), /*languageVersion*/ ts.ScriptTarget.Latest)
-        });
+        const libFileNameSourceFileMap = ts.createMapWithEntry<ts.SourceFile>(defaultLibFileName,
+            createSourceFileAndAssertInvariants(defaultLibFileName, IO.readFile(libFolder + "lib.es5.d.ts"), /*languageVersion*/ ts.ScriptTarget.Latest));
 
         export function getDefaultLibrarySourceFile(fileName = defaultLibFileName): ts.SourceFile {
             if (!isDefaultLibraryFile(fileName)) {
                 return undefined;
             }
 
-            if (!libFileNameSourceFileMap[fileName]) {
-                libFileNameSourceFileMap[fileName] = createSourceFileAndAssertInvariants(fileName, IO.readFile(libFolder + fileName), ts.ScriptTarget.Latest);
+            if (!libFileNameSourceFileMap.get(fileName)) {
+                libFileNameSourceFileMap.set(fileName, createSourceFileAndAssertInvariants(fileName, IO.readFile(libFolder + fileName), ts.ScriptTarget.Latest));
             }
-            return libFileNameSourceFileMap[fileName];
+            return libFileNameSourceFileMap.get(fileName);
         }
 
         export function getDefaultLibFileName(options: ts.CompilerOptions): string {
@@ -1079,16 +1078,16 @@ namespace Harness {
             { name: "symlink", type: "string" }
         ];
 
-        let optionsIndex: ts.Map<ts.CommandLineOption>;
+        let optionsIndex: ts.Map<string, ts.CommandLineOption>;
         function getCommandLineOption(name: string): ts.CommandLineOption {
             if (!optionsIndex) {
-                optionsIndex = ts.createMap<ts.CommandLineOption>();
+                optionsIndex = new ts.StringMap<ts.CommandLineOption>();
                 const optionDeclarations = harnessOptionDeclarations.concat(ts.optionDeclarations);
                 for (const option of optionDeclarations) {
-                    optionsIndex[option.name.toLowerCase()] = option;
+                    optionsIndex.set(option.name.toLowerCase(), option);
                 }
             }
-            return optionsIndex[name.toLowerCase()];
+            return optionsIndex.get(name.toLowerCase());
         }
 
         export function setCompilerOptionsFromHarnessSetting(settings: Harness.TestCaseParser.CompilerSettings, options: ts.CompilerOptions & HarnessOptions): void {
@@ -1439,10 +1438,10 @@ namespace Harness {
 
             const fullWalker = new TypeWriterWalker(program, /*fullTypeCheck*/ true);
 
-            const fullResults = ts.createMap<TypeWriterResult[]>();
+            const fullResults = new ts.StringMap<TypeWriterResult[]>();
 
             for (const sourceFile of allFiles) {
-                fullResults[sourceFile.unitName] = fullWalker.getTypeAndSymbols(sourceFile.unitName);
+                fullResults.set(sourceFile.unitName, fullWalker.getTypeAndSymbols(sourceFile.unitName));
             }
 
             // Produce baselines.  The first gives the types for all expressions.
@@ -1489,13 +1488,13 @@ namespace Harness {
                 Harness.Baseline.runBaseline(outputFileName, () => fullBaseLine, opts);
             }
 
-            function generateBaseLine(typeWriterResults: ts.Map<TypeWriterResult[]>, isSymbolBaseline: boolean): string {
+            function generateBaseLine(typeWriterResults: ts.Map<string, TypeWriterResult[]>, isSymbolBaseline: boolean): string {
                 const typeLines: string[] = [];
                 const typeMap: { [fileName: string]: { [lineNum: number]: string[]; } } = {};
 
                 allFiles.forEach(file => {
                     const codeLines = file.content.split("\n");
-                    typeWriterResults[file.unitName].forEach(result => {
+                    typeWriterResults.get(file.unitName).forEach(result => {
                         if (isSymbolBaseline && !result.symbol) {
                             return;
                         }
diff --git a/src/harness/harnessLanguageService.ts b/src/harness/harnessLanguageService.ts
index 8d90166ea8442..38b780c5900a0 100644
--- a/src/harness/harnessLanguageService.ts
+++ b/src/harness/harnessLanguageService.ts
@@ -262,7 +262,7 @@ namespace Harness.LanguageService {
                 this.getModuleResolutionsForFile = (fileName) => {
                     const scriptInfo = this.getScriptInfo(fileName);
                     const preprocessInfo = ts.preProcessFile(scriptInfo.content, /*readImportFiles*/ true);
-                    const imports = ts.createMap<string>();
+                    const imports: ts.MapLike<string> = {};
                     for (const module of preprocessInfo.importedFiles) {
                         const resolutionInfo = ts.resolveModuleName(module.fileName, fileName, compilerOptions, moduleResolutionHost);
                         if (resolutionInfo.resolvedModule) {
@@ -275,7 +275,7 @@ namespace Harness.LanguageService {
                     const scriptInfo = this.getScriptInfo(fileName);
                     if (scriptInfo) {
                         const preprocessInfo = ts.preProcessFile(scriptInfo.content, /*readImportFiles*/ false);
-                        const resolutions = ts.createMap<ts.ResolvedTypeReferenceDirective>();
+                        const resolutions: ts.MapLike<ts.ResolvedTypeReferenceDirective> = {};
                         const settings = this.nativeHost.getCompilationSettings();
                         for (const typeReferenceDirective of preprocessInfo.typeReferenceDirectives) {
                             const resolutionInfo = ts.resolveTypeReferenceDirective(typeReferenceDirective.fileName, fileName, settings, moduleResolutionHost);
diff --git a/src/harness/loggedIO.ts b/src/harness/loggedIO.ts
index 07dbf4a4e1c43..a4cab886727ba 100644
--- a/src/harness/loggedIO.ts
+++ b/src/harness/loggedIO.ts
@@ -91,13 +91,11 @@ namespace Playback {
     }
 
     function memoize<T>(func: (s: string) => T): Memoized<T> {
-        let lookup: { [s: string]: T } = {};
-        const run: Memoized<T> = <Memoized<T>>((s: string) => {
-            if (lookup.hasOwnProperty(s)) return lookup[s];
-            return lookup[s] = func(s);
-        });
+        const lookup = new ts.StringMap<T>();
+        const run: Memoized<T> = <Memoized<T>>((s: string) =>
+            ts.getOrUpdateAndAllowUndefined(lookup, s, func));
         run.reset = () => {
-            lookup = undefined;
+            lookup.clear();
         };
 
         return run;
diff --git a/src/harness/projectsRunner.ts b/src/harness/projectsRunner.ts
index 415c09caff6d9..5f98320b84863 100644
--- a/src/harness/projectsRunner.ts
+++ b/src/harness/projectsRunner.ts
@@ -256,17 +256,20 @@ class ProjectRunner extends RunnerBase {
                 // Set the values specified using json
                 const optionNameMap = ts.arrayToMap(ts.optionDeclarations, option => option.name);
                 for (const name in testCase) {
-                    if (name !== "mapRoot" && name !== "sourceRoot" && name in optionNameMap) {
-                        const option = optionNameMap[name];
-                        const optType = option.type;
-                        let value = <any>testCase[name];
-                        if (typeof optType !== "string") {
-                            const key = value.toLowerCase();
-                            if (key in optType) {
-                                value = optType[key];
+                    if (name !== "mapRoot" && name !== "sourceRoot") {
+                        const option = optionNameMap.get(name);
+                        if (option !== undefined) {
+                            const optType = option.type;
+                            let value = <any>testCase[name];
+                            if (typeof optType !== "string") {
+                                const key = value.toLowerCase();
+                                const translation = optType.get(key);
+                                if (translation !== undefined) {
+                                    value = translation;
+                                }
                             }
+                            compilerOptions[option.name] = value;
                         }
-                        compilerOptions[option.name] = value;
                     }
                 }
 
diff --git a/src/harness/unittests/cachingInServerLSHost.ts b/src/harness/unittests/cachingInServerLSHost.ts
index 9489feb43e9d4..97a0adf6964d5 100644
--- a/src/harness/unittests/cachingInServerLSHost.ts
+++ b/src/harness/unittests/cachingInServerLSHost.ts
@@ -6,17 +6,17 @@ namespace ts {
         content: string;
     }
 
-    function createDefaultServerHost(fileMap: Map<File>): server.ServerHost {
-        const existingDirectories = createMap<boolean>();
-        for (const name in fileMap) {
+    function createDefaultServerHost(fileMap: Map<string, File>): server.ServerHost {
+        const existingDirectories = new StringSet();
+        forEachKeyInMap(fileMap, name => {
             let dir = getDirectoryPath(name);
             let previous: string;
             do {
-                existingDirectories[dir] = true;
+                existingDirectories.add(dir);
                 previous = dir;
                 dir = getDirectoryPath(dir);
             } while (dir !== previous);
-        }
+        });
         return {
             args: <string[]>[],
             newLine: "\r\n",
@@ -24,7 +24,8 @@ namespace ts {
             write: (s: string) => {
             },
             readFile: (path: string, encoding?: string): string => {
-                return path in fileMap ? fileMap[path].content : undefined;
+                const file = fileMap.get(path);
+                return file !== undefined ? file.content : undefined;
             },
             writeFile: (path: string, data: string, writeByteOrderMark?: boolean) => {
                 throw new Error("NYI");
@@ -33,10 +34,10 @@ namespace ts {
                 throw new Error("NYI");
             },
             fileExists: (path: string): boolean => {
-                return path in fileMap;
+                return fileMap.has(path);
             },
             directoryExists: (path: string): boolean => {
-                return existingDirectories[path] || false;
+                return existingDirectories.has(path);
             },
             createDirectory: (path: string) => {
             },
@@ -105,7 +106,7 @@ namespace ts {
                 content: `foo()`
             };
 
-            const serverHost = createDefaultServerHost(createMap({ [root.name]: root, [imported.name]: imported }));
+            const serverHost = createDefaultServerHost(mapOfMapLike({ [root.name]: root, [imported.name]: imported }));
             const { project, rootScriptInfo } = createProject(root.name, serverHost);
 
             // ensure that imported file was found
@@ -192,7 +193,7 @@ namespace ts {
                 content: `export var y = 1`
             };
 
-            const fileMap = createMap({ [root.name]: root });
+            const fileMap = mapOfMapLike({ [root.name]: root });
             const serverHost = createDefaultServerHost(fileMap);
             const originalFileExists = serverHost.fileExists;
 
@@ -216,7 +217,7 @@ namespace ts {
             assert.isTrue(typeof diags[0].messageText === "string" && ((<string>diags[0].messageText).indexOf("Cannot find module") === 0), "should be 'cannot find module' message");
 
             // assert that import will success once file appear on disk
-            fileMap[imported.name] = imported;
+            fileMap.set(imported.name, imported);
             fileExistsCalledForBar = false;
             rootScriptInfo.editContent(0, root.content.length, `import {y} from "bar"`);
 
diff --git a/src/harness/unittests/moduleResolution.ts b/src/harness/unittests/moduleResolution.ts
index 3e1ac171216e0..a3f8367bb4a08 100644
--- a/src/harness/unittests/moduleResolution.ts
+++ b/src/harness/unittests/moduleResolution.ts
@@ -10,11 +10,11 @@ namespace ts {
         const map = arrayToMap(files, f => f.name);
 
         if (hasDirectoryExists) {
-            const directories = createMap<string>();
+            const directories = new StringSet();
             for (const f of files) {
                 let name = getDirectoryPath(f.name);
                 while (true) {
-                    directories[name] = name;
+                    directories.add(name);
                     const baseName = getDirectoryPath(name);
                     if (baseName === name) {
                         break;
@@ -24,20 +24,19 @@ namespace ts {
             }
             return {
                 readFile,
-                directoryExists: path => {
-                    return path in directories;
-                },
+                directoryExists: path => directories.has(path),
                 fileExists: path => {
-                    assert.isTrue(getDirectoryPath(path) in directories, `'fileExists' '${path}' request in non-existing directory`);
-                    return path in map;
+                    assert.isTrue(directories.has(getDirectoryPath(path)), `'fileExists' '${path}' request in non-existing directory`);
+                    return map.has(path);
                 }
             };
         }
         else {
-            return { readFile, fileExists: path => path in map, };
+            return { readFile, fileExists: path => map.has(path) };
         }
         function readFile(path: string): string {
-            return path in map ? map[path].content : undefined;
+            const file = map.get(path);
+            return file !== undefined ? file.content : undefined;
         }
     }
 
@@ -282,12 +281,13 @@ namespace ts {
     });
 
     describe("Module resolution - relative imports", () => {
-        function test(files: Map<string>, currentDirectory: string, rootFiles: string[], expectedFilesCount: number, relativeNamesToCheck: string[]) {
+        function test(files: Map<string, string>, currentDirectory: string, rootFiles: string[], expectedFilesCount: number, relativeNamesToCheck: string[]) {
             const options: CompilerOptions = { module: ModuleKind.CommonJS };
             const host: CompilerHost = {
                 getSourceFile: (fileName: string, languageVersion: ScriptTarget) => {
                     const path = normalizePath(combinePaths(currentDirectory, fileName));
-                    return path in files ? createSourceFile(fileName, files[path], languageVersion) : undefined;
+                    const file = files.get(path);
+                    return file !== undefined ? createSourceFile(fileName, file, languageVersion) : undefined;
                 },
                 getDefaultLibFileName: () => "lib.d.ts",
                 writeFile: (fileName, content): void => { throw new Error("NotImplemented"); },
@@ -298,7 +298,7 @@ namespace ts {
                 useCaseSensitiveFileNames: () => false,
                 fileExists: fileName => {
                     const path = normalizePath(combinePaths(currentDirectory, fileName));
-                    return path in files;
+                    return files.has(path);
                 },
                 readFile: (fileName): string => { throw new Error("NotImplemented"); }
             };
@@ -318,7 +318,7 @@ namespace ts {
         }
 
         it("should find all modules", () => {
-            const files = createMap({
+            const files = mapOfMapLike({
                 "/a/b/c/first/shared.ts": `
 class A {}
 export = A`,
@@ -337,7 +337,7 @@ export = C;
         });
 
         it("should find modules in node_modules", () => {
-            const files = createMap({
+            const files = mapOfMapLike({
                 "/parent/node_modules/mod/index.d.ts": "export var x",
                 "/parent/app/myapp.ts": `import {x} from "mod"`
             });
@@ -345,7 +345,7 @@ export = C;
         });
 
         it("should find file referenced via absolute and relative names", () => {
-            const files = createMap({
+            const files = mapOfMapLike({
                 "/a/b/c.ts": `/// <reference path="b.ts"/>`,
                 "/a/b/b.ts": "var x"
             });
@@ -355,10 +355,10 @@ export = C;
 
     describe("Files with different casing", () => {
         const library = createSourceFile("lib.d.ts", "", ScriptTarget.ES5);
-        function test(files: Map<string>, options: CompilerOptions, currentDirectory: string, useCaseSensitiveFileNames: boolean, rootFiles: string[], diagnosticCodes: number[]): void {
+        function test(files: Map<string, string>, options: CompilerOptions, currentDirectory: string, useCaseSensitiveFileNames: boolean, rootFiles: string[], diagnosticCodes: number[]): void {
             const getCanonicalFileName = createGetCanonicalFileName(useCaseSensitiveFileNames);
             if (!useCaseSensitiveFileNames) {
-                files = reduceProperties(files, (files, file, fileName) => (files[getCanonicalFileName(fileName)] = file, files), createMap<string>());
+                files = transformKeys(files, getCanonicalFileName);
             }
 
             const host: CompilerHost = {
@@ -367,7 +367,8 @@ export = C;
                         return library;
                     }
                     const path = getCanonicalFileName(normalizePath(combinePaths(currentDirectory, fileName)));
-                    return path in files ? createSourceFile(fileName, files[path], languageVersion) : undefined;
+                    const file = files.get(path);
+                    return file !== undefined ? createSourceFile(fileName, file, languageVersion) : undefined;
                 },
                 getDefaultLibFileName: () => "lib.d.ts",
                 writeFile: (fileName, content): void => { throw new Error("NotImplemented"); },
@@ -378,7 +379,7 @@ export = C;
                 useCaseSensitiveFileNames: () => useCaseSensitiveFileNames,
                 fileExists: fileName => {
                     const path = getCanonicalFileName(normalizePath(combinePaths(currentDirectory, fileName)));
-                    return path in files;
+                    return files.has(path);
                 },
                 readFile: (fileName): string => { throw new Error("NotImplemented"); }
             };
@@ -391,7 +392,7 @@ export = C;
         }
 
         it("should succeed when the same file is referenced using absolute and relative names", () => {
-            const files = createMap({
+            const files = mapOfMapLike({
                 "/a/b/c.ts": `/// <reference path="d.ts"/>`,
                 "/a/b/d.ts": "var x"
             });
@@ -399,7 +400,7 @@ export = C;
         });
 
         it("should fail when two files used in program differ only in casing (tripleslash references)", () => {
-            const files = createMap({
+            const files = mapOfMapLike({
                 "/a/b/c.ts": `/// <reference path="D.ts"/>`,
                 "/a/b/d.ts": "var x"
             });
@@ -407,7 +408,7 @@ export = C;
         });
 
         it("should fail when two files used in program differ only in casing (imports)", () => {
-            const files = createMap({
+            const files = mapOfMapLike({
                 "/a/b/c.ts": `import {x} from "D"`,
                 "/a/b/d.ts": "export var x"
             });
@@ -415,7 +416,7 @@ export = C;
         });
 
         it("should fail when two files used in program differ only in casing (imports, relative module names)", () => {
-            const files = createMap({
+            const files = mapOfMapLike({
                 "moduleA.ts": `import {x} from "./ModuleB"`,
                 "moduleB.ts": "export var x"
             });
@@ -423,7 +424,7 @@ export = C;
         });
 
         it("should fail when two files exist on disk that differs only in casing", () => {
-            const files = createMap({
+            const files = mapOfMapLike({
                 "/a/b/c.ts": `import {x} from "D"`,
                 "/a/b/D.ts": "export var x",
                 "/a/b/d.ts": "export var y"
@@ -432,7 +433,7 @@ export = C;
         });
 
         it("should fail when module name in 'require' calls has inconsistent casing", () => {
-            const files = createMap({
+            const files = mapOfMapLike({
                 "moduleA.ts": `import a = require("./ModuleC")`,
                 "moduleB.ts": `import a = require("./moduleC")`,
                 "moduleC.ts": "export var x"
@@ -441,7 +442,7 @@ export = C;
         });
 
         it("should fail when module names in 'require' calls has inconsistent casing and current directory has uppercase chars", () => {
-            const files = createMap({
+            const files = mapOfMapLike({
                 "/a/B/c/moduleA.ts": `import a = require("./ModuleC")`,
                 "/a/B/c/moduleB.ts": `import a = require("./moduleC")`,
                 "/a/B/c/moduleC.ts": "export var x",
@@ -453,7 +454,7 @@ import b = require("./moduleB");
             test(files, { module: ts.ModuleKind.CommonJS, forceConsistentCasingInFileNames: true },  "/a/B/c", /*useCaseSensitiveFileNames*/ false, ["moduleD.ts"], [1149]);
         });
         it("should not fail when module names in 'require' calls has consistent casing and current directory has uppercase chars", () => {
-            const files = createMap({
+            const files = mapOfMapLike({
                 "/a/B/c/moduleA.ts": `import a = require("./moduleC")`,
                 "/a/B/c/moduleB.ts": `import a = require("./moduleC")`,
                 "/a/B/c/moduleC.ts": "export var x",
@@ -1019,8 +1020,8 @@ import b = require("./moduleB");
             const names = map(files, f => f.name);
             const sourceFiles = arrayToMap(map(files, f => createSourceFile(f.name, f.content, ScriptTarget.ES6)), f => f.fileName);
             const compilerHost: CompilerHost = {
-                fileExists : fileName => fileName in sourceFiles,
-                getSourceFile: fileName => sourceFiles[fileName],
+                fileExists : fileName => sourceFiles.has(fileName),
+                getSourceFile: fileName => sourceFiles.get(fileName),
                 getDefaultLibFileName: () => "lib.d.ts",
                 writeFile(file, text) {
                     throw new Error("NYI");
@@ -1030,7 +1031,10 @@ import b = require("./moduleB");
                 getCanonicalFileName: f => f.toLowerCase(),
                 getNewLine: () => "\r\n",
                 useCaseSensitiveFileNames: () => false,
-                readFile: fileName => fileName in sourceFiles ? sourceFiles[fileName].text : undefined
+                readFile: fileName => {
+                    const file = sourceFiles.get(fileName);
+                    return file !== undefined ? file.text : undefined;
+                }
             };
             const program1 = createProgram(names, {}, compilerHost);
             const diagnostics1 = program1.getFileProcessingDiagnostics().getDiagnostics();
diff --git a/src/harness/unittests/reuseProgramStructure.ts b/src/harness/unittests/reuseProgramStructure.ts
index 60687d34c55af..ba3923aeb3723 100644
--- a/src/harness/unittests/reuseProgramStructure.ts
+++ b/src/harness/unittests/reuseProgramStructure.ts
@@ -106,7 +106,7 @@ namespace ts {
 
         return {
             getSourceFile(fileName): SourceFile {
-                return files[fileName];
+                return files.get(fileName);
             },
             getDefaultLibFileName(): string {
                 return "lib.d.ts";
@@ -129,9 +129,10 @@ namespace ts {
             getNewLine(): string {
                 return sys ? sys.newLine : newLine;
             },
-            fileExists: fileName => fileName in files,
+            fileExists: fileName => files.has(fileName),
             readFile: fileName => {
-                return fileName in files ? files[fileName].text : undefined;
+                const file = files.get(fileName);
+                return file !== undefined ? file.text : undefined;
             }
         };
     }
@@ -174,7 +175,7 @@ namespace ts {
         return false;
     }
 
-    function checkCache<T>(caption: string, program: Program, fileName: string, expectedContent: Map<T>, getCache: (f: SourceFile) => Map<T>, entryChecker: (expected: T, original: T) => boolean): void {
+    function checkCache<T>(caption: string, program: Program, fileName: string, expectedContent: Map<string, T>, getCache: (f: SourceFile) => Map<string, T>, entryChecker: (expected: T, original: T) => boolean): void {
         const file = program.getSourceFile(fileName);
         assert.isTrue(file !== undefined, `cannot find file ${fileName}`);
         const cache = getCache(file);
@@ -183,15 +184,15 @@ namespace ts {
         }
         else {
             assert.isTrue(cache !== undefined, `expected ${caption} to be set`);
-            assert.isTrue(equalOwnProperties(expectedContent, cache, entryChecker), `contents of ${caption} did not match the expected contents.`);
+            assert.isTrue(mapsAreEqual(expectedContent, cache, entryChecker), `contents of ${caption} did not match the expected contents.`);
         }
     }
 
-    function checkResolvedModulesCache(program: Program, fileName: string, expectedContent: Map<ResolvedModule>): void {
+    function checkResolvedModulesCache(program: Program, fileName: string, expectedContent: Map<string, ResolvedModule>): void {
         checkCache("resolved modules", program, fileName, expectedContent, f => f.resolvedModules, checkResolvedModule);
     }
 
-    function checkResolvedTypeDirectivesCache(program: Program, fileName: string, expectedContent: Map<ResolvedTypeReferenceDirective>): void {
+    function checkResolvedTypeDirectivesCache(program: Program, fileName: string, expectedContent: Map<string, ResolvedTypeReferenceDirective>): void {
         checkCache("resolved type directives", program, fileName, expectedContent, f => f.resolvedTypeReferenceDirectiveNames, checkResolvedTypeDirective);
     }
 
@@ -306,7 +307,7 @@ namespace ts {
             const options: CompilerOptions = { target };
 
             const program_1 = newProgram(files, ["a.ts"], options);
-            checkResolvedModulesCache(program_1, "a.ts", createMap({ "b": { resolvedFileName: "b.ts" } }));
+            checkResolvedModulesCache(program_1, "a.ts", mapOfMapLike({ "b": { resolvedFileName: "b.ts" } }));
             checkResolvedModulesCache(program_1, "b.ts", undefined);
 
             const program_2 = updateProgram(program_1, ["a.ts"], options, files => {
@@ -315,7 +316,7 @@ namespace ts {
             assert.isTrue(program_1.structureIsReused);
 
             // content of resolution cache should not change
-            checkResolvedModulesCache(program_1, "a.ts", createMap({ "b": { resolvedFileName: "b.ts" } }));
+            checkResolvedModulesCache(program_1, "a.ts", mapOfMapLike({ "b": { resolvedFileName: "b.ts" } }));
             checkResolvedModulesCache(program_1, "b.ts", undefined);
 
             // imports has changed - program is not reused
@@ -332,7 +333,7 @@ namespace ts {
                 files[0].text = files[0].text.updateImportsAndExports(newImports);
             });
             assert.isTrue(!program_3.structureIsReused);
-            checkResolvedModulesCache(program_4, "a.ts", createMap({ "b": { resolvedFileName: "b.ts" }, "c": undefined }));
+            checkResolvedModulesCache(program_4, "a.ts", mapOfMapLike({ "b": { resolvedFileName: "b.ts" }, "c": undefined }));
         });
 
         it("resolved type directives cache follows type directives", () => {
@@ -343,7 +344,7 @@ namespace ts {
             const options: CompilerOptions = { target, typeRoots: ["/types"] };
 
             const program_1 = newProgram(files, ["/a.ts"], options);
-            checkResolvedTypeDirectivesCache(program_1, "/a.ts", createMap({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
+            checkResolvedTypeDirectivesCache(program_1, "/a.ts", mapOfMapLike({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
             checkResolvedTypeDirectivesCache(program_1, "/types/typedefs/index.d.ts", undefined);
 
             const program_2 = updateProgram(program_1, ["/a.ts"], options, files => {
@@ -352,7 +353,7 @@ namespace ts {
             assert.isTrue(program_1.structureIsReused);
 
             // content of resolution cache should not change
-            checkResolvedTypeDirectivesCache(program_1, "/a.ts", createMap({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
+            checkResolvedTypeDirectivesCache(program_1, "/a.ts", mapOfMapLike({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
             checkResolvedTypeDirectivesCache(program_1, "/types/typedefs/index.d.ts", undefined);
 
             // type reference directives has changed - program is not reused
@@ -370,7 +371,7 @@ namespace ts {
                 files[0].text = files[0].text.updateReferences(newReferences);
             });
             assert.isTrue(!program_3.structureIsReused);
-            checkResolvedTypeDirectivesCache(program_1, "/a.ts", createMap({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
+            checkResolvedTypeDirectivesCache(program_1, "/a.ts", mapOfMapLike({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
         });
     });
 
diff --git a/src/harness/unittests/session.ts b/src/harness/unittests/session.ts
index badbbaf526b7a..e83e9b55f04d5 100644
--- a/src/harness/unittests/session.ts
+++ b/src/harness/unittests/session.ts
@@ -112,9 +112,6 @@ namespace ts.server {
             it("should not throw when commands are executed with invalid arguments", () => {
                 let i = 0;
                 for (const name in CommandNames) {
-                    if (!Object.prototype.hasOwnProperty.call(CommandNames, name)) {
-                        continue;
-                    }
                     const req: protocol.Request = {
                         command: name,
                         seq: i,
@@ -367,15 +364,15 @@ namespace ts.server {
         class InProcClient {
             private server: InProcSession;
             private seq = 0;
-            private callbacks = createMap<(resp: protocol.Response) => void>();
-            private eventHandlers = createMap<(args: any) => void>();
+            private callbacks = new NumberMap<number, (resp: protocol.Response) => void>();
+            private eventHandlers = new StringMap<(args: any) => void>();
 
             handle(msg: protocol.Message): void {
                 if (msg.type === "response") {
                     const response = <protocol.Response>msg;
-                    if (response.request_seq in this.callbacks) {
-                        this.callbacks[response.request_seq](response);
-                        delete this.callbacks[response.request_seq];
+                    const callback = tryDelete(this.callbacks, response.request_seq);
+                    if (callback !== undefined) {
+                        callback(response);
                     }
                 }
                 else if (msg.type === "event") {
@@ -385,13 +382,14 @@ namespace ts.server {
             }
 
             emit(name: string, args: any): void {
-                if (name in this.eventHandlers) {
-                    this.eventHandlers[name](args);
+                const handler = this.eventHandlers.get(name);
+                if (handler !== undefined) {
+                    handler(args);
                 }
             }
 
             on(name: string, handler: (args: any) => void): void {
-                this.eventHandlers[name] = handler;
+                this.eventHandlers.set(name, handler);
             }
 
             connect(session: InProcSession): void {
@@ -409,7 +407,7 @@ namespace ts.server {
                     command,
                     arguments: args
                 });
-                this.callbacks[this.seq] = callback;
+                this.callbacks.set(this.seq, callback);
             }
         };
 
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index 9f0d6ae6a17d4..ce46fe02e2960 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -238,10 +238,10 @@ namespace ts.projectSystem {
         return entry;
     }
 
-    export function checkMapKeys(caption: string, map: Map<any>, expectedKeys: string[]) {
-        assert.equal(reduceProperties(map, count => count + 1, 0), expectedKeys.length, `${caption}: incorrect size of map`);
+    export function checkMapKeys(caption: string, map: Map<string, any>, expectedKeys: string[]) {
+        assert.equal(mapSize(map), expectedKeys.length, `${caption}: incorrect size of map`);
         for (const name of expectedKeys) {
-            assert.isTrue(name in map, `${caption} is expected to contain ${name}, actual keys: ${Object.keys(map)}`);
+            assert.isTrue(map.has(name), `${caption} is expected to contain ${name}, actual keys: ${keysOfMap(map)}`);
         }
     }
 
@@ -287,38 +287,28 @@ namespace ts.projectSystem {
     }
 
     export class Callbacks {
-        private map: { [n: number]: TimeOutCallback } = {};
+        private map = new NumberMap<number, TimeOutCallback>();
         private nextId = 1;
 
         register(cb: (...args: any[]) => void, args: any[]) {
             const timeoutId = this.nextId;
             this.nextId++;
-            this.map[timeoutId] = cb.bind(undefined, ...args);
+            this.map.set(timeoutId, cb.bind(undefined, ...args));
             return timeoutId;
         }
         unregister(id: any) {
             if (typeof id === "number") {
-                delete this.map[id];
+                this.map.delete(id);
             }
         }
 
         count() {
-            let n = 0;
-/* tslint:disable:no-unused-variable */
-            for (const _ in this.map) {
-/* tslint:enable:no-unused-variable */
-                n++;
-            }
-            return n;
+            return mapSize(this.map);
         }
 
         invoke() {
-            for (const id in this.map) {
-                if (hasProperty(this.map, id)) {
-                    this.map[id]();
-                }
-            }
-            this.map = {};
+            this.map.forEach(callback => { callback(); });
+            this.map.clear();
         }
     }
 
@@ -334,8 +324,9 @@ namespace ts.projectSystem {
         private timeoutCallbacks = new Callbacks();
         private immediateCallbacks = new Callbacks();
 
-        readonly watchedDirectories = createMap<{ cb: DirectoryWatcherCallback, recursive: boolean }[]>();
-        readonly watchedFiles = createMap<FileWatcherCallback[]>();
+        readonly watchedDirectories = new StringMap<{ cb: DirectoryWatcherCallback, recursive: boolean }[]>();
+        readonly watchedFiles = new StringMap<FileWatcherCallback[]>();
+
 
         private filesOrFolders: FileOrFolder[];
 
@@ -430,7 +421,7 @@ namespace ts.projectSystem {
 
         triggerDirectoryWatcherCallback(directoryName: string, fileName: string): void {
             const path = this.toPath(directoryName);
-            const callbacks = this.watchedDirectories[path];
+            const callbacks = this.watchedDirectories.get(path);
             if (callbacks) {
                 for (const callback of callbacks) {
                     callback.cb(fileName);
@@ -440,7 +431,7 @@ namespace ts.projectSystem {
 
         triggerFileWatcherCallback(fileName: string, removed?: boolean): void {
             const path = this.toPath(fileName);
-            const callbacks = this.watchedFiles[path];
+            const callbacks = this.watchedFiles.get(path);
             if (callbacks) {
                 for (const callback of callbacks) {
                     callback(path, removed);
@@ -2084,7 +2075,7 @@ namespace ts.projectSystem {
             const projectFileName = "externalProject";
             const host = createServerHost([f]);
             const projectService = createProjectService(host);
-            // create a project 
+            // create a project
             projectService.openExternalProject({ projectFileName, rootFiles: [toExternalFile(f.path)], options: {} });
             projectService.checkNumberOfProjects({ externalProjects: 1 });
 
diff --git a/src/server/builder.ts b/src/server/builder.ts
index 639c41d2b63e5..bb898cdee9c8f 100644
--- a/src/server/builder.ts
+++ b/src/server/builder.ts
@@ -347,25 +347,26 @@ namespace ts.server {
 
             // Use slice to clone the array to avoid manipulating in place
             const queue = fileInfo.referencedBy.slice(0);
-            const fileNameSet = createMap<ScriptInfo>();
-            fileNameSet[scriptInfo.fileName] = scriptInfo;
+            const fileNameSet = new StringMap<ScriptInfo>();
+            fileNameSet.set(scriptInfo.fileName, scriptInfo);
             while (queue.length > 0) {
                 const processingFileInfo = queue.pop();
                 if (processingFileInfo.updateShapeSignature() && processingFileInfo.referencedBy.length > 0) {
                     for (const potentialFileInfo of processingFileInfo.referencedBy) {
-                        if (!fileNameSet[potentialFileInfo.scriptInfo.fileName]) {
+                        if (!fileNameSet.get(potentialFileInfo.scriptInfo.fileName)) {
                             queue.push(potentialFileInfo);
                         }
                     }
                 }
-                fileNameSet[processingFileInfo.scriptInfo.fileName] = processingFileInfo.scriptInfo;
+                fileNameSet.set(processingFileInfo.scriptInfo.fileName, processingFileInfo.scriptInfo);
             }
+
             const result: string[] = [];
-            for (const fileName in fileNameSet) {
-                if (shouldEmitFile(fileNameSet[fileName])) {
+            fileNameSet.forEach((scriptInfo, fileName) => {
+                if (shouldEmitFile(scriptInfo)) {
                     result.push(fileName);
                 }
-            }
+            });
             return result;
         }
     }
diff --git a/src/server/client.ts b/src/server/client.ts
index 688408dfb88d3..0b82073fb3217 100644
--- a/src/server/client.ts
+++ b/src/server/client.ts
@@ -21,7 +21,7 @@ namespace ts.server {
 
     export class SessionClient implements LanguageService {
         private sequence: number = 0;
-        private lineMaps: ts.Map<number[]> = ts.createMap<number[]>();
+        private lineMaps = new ts.StringMap<number[]>();
         private messages: string[] = [];
         private lastRenameEntry: RenameEntry;
 
@@ -37,10 +37,10 @@ namespace ts.server {
         }
 
         private getLineMap(fileName: string): number[] {
-            let lineMap = this.lineMaps[fileName];
+            let lineMap = this.lineMaps.get(fileName);
             if (!lineMap) {
                 const scriptSnapshot = this.host.getScriptSnapshot(fileName);
-                lineMap = this.lineMaps[fileName] = ts.computeLineStarts(scriptSnapshot.getText(0, scriptSnapshot.getLength()));
+                lineMap = setAndReturn(this.lineMaps, fileName, ts.computeLineStarts(scriptSnapshot.getText(0, scriptSnapshot.getLength())));
             }
             return lineMap;
         }
@@ -146,7 +146,7 @@ namespace ts.server {
 
         changeFile(fileName: string, start: number, end: number, newText: string): void {
             // clear the line map after an edit
-            this.lineMaps[fileName] = undefined;
+            this.lineMaps.set(fileName, undefined);
 
             const lineOffset = this.positionToOneBasedLineOffset(fileName, start);
             const endLineOffset = this.positionToOneBasedLineOffset(fileName, end);
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index 51310c90a6b99..5b0f2d81d3915 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -98,23 +98,24 @@ namespace ts.server {
         /**
          * a path to directory watcher map that detects added tsconfig files
          **/
-        private readonly directoryWatchersForTsconfig: Map<FileWatcher> = createMap<FileWatcher>();
+        private readonly directoryWatchersForTsconfig = new StringMap<FileWatcher>();
         /**
          * count of how many projects are using the directory watcher.
          * If the number becomes 0 for a watcher, then we should close it.
          **/
-        private readonly directoryWatchersRefCount: Map<number> = createMap<number>();
+        private readonly directoryWatchersRefCount = new StringMap<number>();
 
         constructor(private readonly projectService: ProjectService) {
         }
 
         stopWatchingDirectory(directory: string) {
             // if the ref count for this directory watcher drops to 0, it's time to close it
-            this.directoryWatchersRefCount[directory]--;
-            if (this.directoryWatchersRefCount[directory] === 0) {
+            const refCount = this.directoryWatchersRefCount.get(directory) - 1;
+            this.directoryWatchersRefCount.set(directory, refCount);
+            if (refCount === 0) {
                 this.projectService.logger.info(`Close directory watcher for: ${directory}`);
-                this.directoryWatchersForTsconfig[directory].close();
-                delete this.directoryWatchersForTsconfig[directory];
+                this.directoryWatchersForTsconfig.get(directory).close();
+                this.directoryWatchersForTsconfig.delete(directory);
             }
         }
 
@@ -122,13 +123,13 @@ namespace ts.server {
             let currentPath = getDirectoryPath(fileName);
             let parentPath = getDirectoryPath(currentPath);
             while (currentPath != parentPath) {
-                if (!this.directoryWatchersForTsconfig[currentPath]) {
+                if (!this.directoryWatchersForTsconfig.get(currentPath)) {
                     this.projectService.logger.info(`Add watcher for: ${currentPath}`);
-                    this.directoryWatchersForTsconfig[currentPath] = this.projectService.host.watchDirectory(currentPath, callback);
-                    this.directoryWatchersRefCount[currentPath] = 1;
+                    this.directoryWatchersForTsconfig.set(currentPath, this.projectService.host.watchDirectory(currentPath, callback));
+                    this.directoryWatchersRefCount.set(currentPath, 1);
                 }
                 else {
-                    this.directoryWatchersRefCount[currentPath] += 1;
+                    modifyValue(this.directoryWatchersRefCount, currentPath, count => count + 1);
                 }
                 project.directoriesWatchedForTsconfig.push(currentPath);
                 currentPath = parentPath;
@@ -150,7 +151,7 @@ namespace ts.server {
         /**
          * maps external project file name to list of config files that were the part of this project
          */
-        private readonly externalProjectToConfiguredProjectMap: Map<NormalizedPath[]> = createMap<NormalizedPath[]>();
+        private readonly externalProjectToConfiguredProjectMap = new StringMap<NormalizedPath[]>();
 
         /**
          * external projects (configuration and list of root files is not controlled by tsserver)
@@ -325,7 +326,7 @@ namespace ts.server {
             }
             else {
                 if (info && (!info.isOpen)) {
-                    // file has been changed which might affect the set of referenced files in projects that include 
+                    // file has been changed which might affect the set of referenced files in projects that include
                     // this file and set of inferred projects
                     info.reloadFromFile();
                     this.updateProjectGraphs(info.containingProjects);
@@ -343,7 +344,7 @@ namespace ts.server {
             if (!info.isOpen) {
                 this.filenameToScriptInfo.remove(info.path);
 
-                // capture list of projects since detachAllProjects will wipe out original list 
+                // capture list of projects since detachAllProjects will wipe out original list
                 const containingProjects = info.containingProjects.slice();
 
                 info.detachAllProjects();
@@ -493,7 +494,7 @@ namespace ts.server {
                 const inferredProject = this.createInferredProjectWithRootFileIfNecessary(info);
                 if (!this.useSingleInferredProject) {
                     // if useOneInferredProject is not set then try to fixup ownership of open files
-                    // check 'defaultProject !== inferredProject' is necessary to handle cases 
+                    // check 'defaultProject !== inferredProject' is necessary to handle cases
                     // when creation inferred project for some file has added other open files into this project (i.e. as referenced files)
                     // we definitely don't want to delete the project that was just created
                     for (const f of this.openFiles) {
@@ -503,7 +504,7 @@ namespace ts.server {
                         }
                         const defaultProject = f.getDefaultProject();
                         if (isRootFileInInferredProject(info) && defaultProject !== inferredProject && inferredProject.containsScriptInfo(f)) {
-                            // open file used to be root in inferred project, 
+                            // open file used to be root in inferred project,
                             // this inferred project is different from the one we've just created for current file
                             // and new inferred project references this open file.
                             // We should delete old inferred project and attach open file to the new one
@@ -715,7 +716,7 @@ namespace ts.server {
                 files: parsedCommandLine.fileNames,
                 compilerOptions: parsedCommandLine.options,
                 configHasFilesProperty: config["files"] !== undefined,
-                wildcardDirectories: createMap(parsedCommandLine.wildcardDirectories),
+                wildcardDirectories: parsedCommandLine.wildcardDirectories,
                 typingOptions: parsedCommandLine.typingOptions,
                 compileOnSave: parsedCommandLine.compileOnSave
             };
@@ -771,7 +772,7 @@ namespace ts.server {
                 this.documentRegistry,
                 projectOptions.configHasFilesProperty,
                 projectOptions.compilerOptions,
-                projectOptions.wildcardDirectories,
+                mapOfMapLike(projectOptions.wildcardDirectories),
                 /*languageServiceEnabled*/ !sizeLimitExceeded,
                 projectOptions.compileOnSave === undefined ? false : projectOptions.compileOnSave);
 
@@ -829,7 +830,7 @@ namespace ts.server {
         private updateNonInferredProject<T>(project: ExternalProject | ConfiguredProject, newUncheckedFiles: T[], propertyReader: FilePropertyReader<T>, newOptions: CompilerOptions, newTypingOptions: TypingOptions, compileOnSave: boolean, configFileErrors: Diagnostic[]) {
             const oldRootScriptInfos = project.getRootScriptInfos();
             const newRootScriptInfos: ScriptInfo[] = [];
-            const newRootScriptInfoMap: NormalizedPathMap<ScriptInfo> = createNormalizedPathMap<ScriptInfo>();
+            const newRootScriptInfoMap: Map<NormalizedPath, ScriptInfo> = new StringMap<ScriptInfo>();
 
             let projectErrors: Diagnostic[];
             let rootFilesChanged = false;
@@ -857,7 +858,7 @@ namespace ts.server {
                 let toAdd: ScriptInfo[];
                 let toRemove: ScriptInfo[];
                 for (const oldFile of oldRootScriptInfos) {
-                    if (!newRootScriptInfoMap.contains(oldFile.fileName)) {
+                    if (!newRootScriptInfoMap.has(oldFile.fileName)) {
                         (toRemove || (toRemove = [])).push(oldFile);
                     }
                 }
@@ -874,7 +875,7 @@ namespace ts.server {
                 if (toAdd) {
                     for (const f of toAdd) {
                         if (f.isOpen && isRootFileInInferredProject(f)) {
-                            // if file is already root in some inferred project 
+                            // if file is already root in some inferred project
                             // - remove the file from that project and delete the project if necessary
                             const inferredProject = f.containingProjects[0];
                             inferredProject.removeFile(f);
@@ -1023,7 +1024,7 @@ namespace ts.server {
                     this.logger.info(`Host information ${args.hostInfo}`);
                 }
                 if (args.formatOptions) {
-                    mergeMaps(this.hostConfiguration.formatCodeOptions, args.formatOptions);
+                    mergeMapLikes(this.hostConfiguration.formatCodeOptions, args.formatOptions);
                     this.logger.info("Format host information updated");
                 }
             }
@@ -1145,7 +1146,7 @@ namespace ts.server {
                 for (const file of changedFiles) {
                     const scriptInfo = this.getScriptInfo(file.fileName);
                     Debug.assert(!!scriptInfo);
-                    // apply changes in reverse order 
+                    // apply changes in reverse order
                     for (let i = file.changes.length - 1; i >= 0; i--) {
                         const change = file.changes[i];
                         scriptInfo.editContent(change.span.start, change.span.start + change.span.length, change.newText);
@@ -1182,7 +1183,7 @@ namespace ts.server {
 
         closeExternalProject(uncheckedFileName: string, suppressRefresh = false): void {
             const fileName = toNormalizedPath(uncheckedFileName);
-            const configFiles = this.externalProjectToConfiguredProjectMap[fileName];
+            const configFiles = this.externalProjectToConfiguredProjectMap.get(fileName);
             if (configFiles) {
                 let shouldRefreshInferredProjects = false;
                 for (const configFile of configFiles) {
@@ -1190,7 +1191,7 @@ namespace ts.server {
                         shouldRefreshInferredProjects = true;
                     }
                 }
-                delete this.externalProjectToConfiguredProjectMap[fileName];
+                this.externalProjectToConfiguredProjectMap.delete(fileName);
                 if (shouldRefreshInferredProjects && !suppressRefresh) {
                     this.refreshInferredProjects();
                 }
@@ -1237,7 +1238,7 @@ namespace ts.server {
                 // close existing project and later we'll open a set of configured projects for these files
                 this.closeExternalProject(proj.projectFileName, /*suppressRefresh*/ true);
             }
-            else if (this.externalProjectToConfiguredProjectMap[proj.projectFileName]) {
+            else if (this.externalProjectToConfiguredProjectMap.get(proj.projectFileName)) {
                 // this project used to include config files
                 if (!tsConfigFiles) {
                     // config files were removed from the project - close existing external project which in turn will close configured projects
@@ -1245,7 +1246,7 @@ namespace ts.server {
                 }
                 else {
                     // project previously had some config files - compare them with new set of files and close all configured projects that correspond to unused files
-                    const oldConfigFiles = this.externalProjectToConfiguredProjectMap[proj.projectFileName];
+                    const oldConfigFiles = this.externalProjectToConfiguredProjectMap.get(proj.projectFileName);
                     let iNew = 0;
                     let iOld = 0;
                     while (iNew < tsConfigFiles.length && iOld < oldConfigFiles.length) {
@@ -1273,7 +1274,7 @@ namespace ts.server {
             }
             if (tsConfigFiles) {
                 // store the list of tsconfig files that belong to the external project
-                this.externalProjectToConfiguredProjectMap[proj.projectFileName] = tsConfigFiles;
+                this.externalProjectToConfiguredProjectMap.set(proj.projectFileName, tsConfigFiles);
                 for (const tsconfigFile of tsConfigFiles) {
                     let project = this.findConfiguredProjectByProjectName(tsconfigFile);
                     if (!project) {
@@ -1289,7 +1290,7 @@ namespace ts.server {
             }
             else {
                 // no config files - remove the item from the collection
-                delete this.externalProjectToConfiguredProjectMap[proj.projectFileName];
+                this.externalProjectToConfiguredProjectMap.delete(proj.projectFileName);
                 this.createAndAddExternalProject(proj.projectFileName, rootFiles, proj.options, proj.typingOptions);
             }
             this.refreshInferredProjects();
diff --git a/src/server/lsHost.ts b/src/server/lsHost.ts
index 5b33770ce28b1..6585a267b848b 100644
--- a/src/server/lsHost.ts
+++ b/src/server/lsHost.ts
@@ -5,8 +5,8 @@
 namespace ts.server {
     export class LSHost implements ts.LanguageServiceHost, ModuleResolutionHost, ServerLanguageServiceHost {
         private compilationSettings: ts.CompilerOptions;
-        private readonly resolvedModuleNames: ts.FileMap<Map<ResolvedModuleWithFailedLookupLocations>>;
-        private readonly resolvedTypeReferenceDirectives: ts.FileMap<Map<ResolvedTypeReferenceDirectiveWithFailedLookupLocations>>;
+        private readonly resolvedModuleNames: ts.FileMap<Map<string, ResolvedModuleWithFailedLookupLocations>>;
+        private readonly resolvedTypeReferenceDirectives: ts.FileMap<Map<string, ResolvedTypeReferenceDirectiveWithFailedLookupLocations>>;
         private readonly getCanonicalFileName: (fileName: string) => string;
 
         private readonly resolveModuleName: typeof resolveModuleName;
@@ -14,8 +14,8 @@ namespace ts.server {
 
         constructor(private readonly host: ServerHost, private readonly project: Project, private readonly cancellationToken: HostCancellationToken) {
             this.getCanonicalFileName = ts.createGetCanonicalFileName(this.host.useCaseSensitiveFileNames);
-            this.resolvedModuleNames = createFileMap<Map<ResolvedModuleWithFailedLookupLocations>>();
-            this.resolvedTypeReferenceDirectives = createFileMap<Map<ResolvedTypeReferenceDirectiveWithFailedLookupLocations>>();
+            this.resolvedModuleNames = createFileMap<Map<string, ResolvedModuleWithFailedLookupLocations>>();
+            this.resolvedTypeReferenceDirectives = createFileMap<Map<string, ResolvedTypeReferenceDirectiveWithFailedLookupLocations>>();
 
             if (host.trace) {
                 this.trace = s => host.trace(s);
@@ -31,7 +31,7 @@ namespace ts.server {
                     }
                 }
                 // create different collection of failed lookup locations for second pass
-                // if it will fail and we've already found something during the first pass - we don't want to pollute its results 
+                // if it will fail and we've already found something during the first pass - we don't want to pollute its results
                 const secondaryLookupFailedLookupLocations: string[] = [];
                 const globalCache = this.project.projectService.typingsInstaller.globalTypingsCacheLocation;
                 if (this.project.getTypingOptions().enableAutoDiscovery && globalCache) {
@@ -55,28 +55,28 @@ namespace ts.server {
         private resolveNamesWithLocalCache<T extends { failedLookupLocations: string[] }, R>(
             names: string[],
             containingFile: string,
-            cache: ts.FileMap<Map<T>>,
+            cache: ts.FileMap<Map<string, T>>,
             loader: (name: string, containingFile: string, options: CompilerOptions, host: ModuleResolutionHost) => T,
             getResult: (s: T) => R): R[] {
 
             const path = toPath(containingFile, this.host.getCurrentDirectory(), this.getCanonicalFileName);
             const currentResolutionsInFile = cache.get(path);
 
-            const newResolutions: Map<T> = createMap<T>();
+            const newResolutions = new StringMap<T>();
             const resolvedModules: R[] = [];
             const compilerOptions = this.getCompilationSettings();
 
             for (const name of names) {
                 // check if this is a duplicate entry in the list
-                let resolution = newResolutions[name];
+                let resolution = newResolutions.get(name);
                 if (!resolution) {
-                    const existingResolution = currentResolutionsInFile && currentResolutionsInFile[name];
+                    const existingResolution = currentResolutionsInFile && currentResolutionsInFile.get(name);
                     if (moduleResolutionIsValid(existingResolution)) {
                         // ok, it is safe to use existing name resolution results
                         resolution = existingResolution;
                     }
                     else {
-                        newResolutions[name] = resolution = loader(name, containingFile, compilerOptions, this);
+                        newResolutions.set(name, resolution = loader(name, containingFile, compilerOptions, this));
                     }
                 }
 
diff --git a/src/server/project.ts b/src/server/project.ts
index b59efb03cfd54..4d65e59d59a9c 100644
--- a/src/server/project.ts
+++ b/src/server/project.ts
@@ -47,7 +47,7 @@ namespace ts.server {
         /**
          * Set of files that was returned from the last call to getChangesSinceVersion.
          */
-        private lastReportedFileNames: Map<string>;
+        private lastReportedFileNames: Map<string, string>;
         /**
          * Last version that was reported.
          */
@@ -437,16 +437,16 @@ namespace ts.server {
 
                 const added: string[] = [];
                 const removed: string[] = [];
-                for (const id in currentFiles) {
-                    if (!hasProperty(lastReportedFileNames, id)) {
+                forEachKeyInMap(currentFiles, id => {
+                    if (!lastReportedFileNames.has(id)) {
                         added.push(id);
                     }
-                }
-                for (const id in lastReportedFileNames) {
-                    if (!hasProperty(currentFiles, id)) {
+                });
+                forEachKeyInMap(lastReportedFileNames, id => {
+                    if (!currentFiles.has(id)) {
                         removed.push(id);
                     }
-                }
+                });
                 this.lastReportedFileNames = currentFiles;
                 this.lastReportedVersion = this.projectStructureVersion;
                 return { info, changes: { added, removed }, projectErrors: this.projectErrors };
@@ -472,7 +472,7 @@ namespace ts.server {
             // We need to use a set here since the code can contain the same import twice,
             // but that will only be one dependency.
             // To avoid invernal conversion, the key of the referencedFiles map must be of type Path
-            const referencedFiles = createMap<boolean>();
+            const referencedFiles = new StringSet();
             if (sourceFile.imports && sourceFile.imports.length > 0) {
                 const checker: TypeChecker = this.program.getTypeChecker();
                 for (const importName of sourceFile.imports) {
@@ -480,7 +480,7 @@ namespace ts.server {
                     if (symbol && symbol.declarations && symbol.declarations[0]) {
                         const declarationSourceFile = symbol.declarations[0].getSourceFile();
                         if (declarationSourceFile) {
-                            referencedFiles[declarationSourceFile.path] = true;
+                            referencedFiles.add(declarationSourceFile.path);
                         }
                     }
                 }
@@ -492,26 +492,24 @@ namespace ts.server {
             if (sourceFile.referencedFiles && sourceFile.referencedFiles.length > 0) {
                 for (const referencedFile of sourceFile.referencedFiles) {
                     const referencedPath = toPath(referencedFile.fileName, currentDirectory, getCanonicalFileName);
-                    referencedFiles[referencedPath] = true;
+                    referencedFiles.add(referencedPath);
                 }
             }
 
             // Handle type reference directives
             if (sourceFile.resolvedTypeReferenceDirectiveNames) {
-                for (const typeName in sourceFile.resolvedTypeReferenceDirectiveNames) {
-                    const resolvedTypeReferenceDirective = sourceFile.resolvedTypeReferenceDirectiveNames[typeName];
+                sourceFile.resolvedTypeReferenceDirectiveNames.forEach(resolvedTypeReferenceDirective => {
                     if (!resolvedTypeReferenceDirective) {
-                        continue;
+                        return;
                     }
 
                     const fileName = resolvedTypeReferenceDirective.resolvedFileName;
                     const typeFilePath = toPath(fileName, currentDirectory, getCanonicalFileName);
-                    referencedFiles[typeFilePath] = true;
-                }
+                    referencedFiles.add(typeFilePath);
+                });
             }
 
-            const allFileNames = map(Object.keys(referencedFiles), key => <Path>key);
-            return filter(allFileNames, file => this.projectService.host.fileExists(file));
+            return filterSetToArray(referencedFiles, file => this.projectService.host.fileExists(file)) as Path[];
         }
 
         // remove a root file from project
@@ -582,7 +580,7 @@ namespace ts.server {
         private typingOptions: TypingOptions;
         private projectFileWatcher: FileWatcher;
         private directoryWatcher: FileWatcher;
-        private directoriesWatchedForWildcards: Map<FileWatcher>;
+        private directoriesWatchedForWildcards: Map<string, FileWatcher>;
         private typeRootsWatchers: FileWatcher[];
 
         /** Used for configured projects which may have multiple open roots */
@@ -593,7 +591,7 @@ namespace ts.server {
             documentRegistry: ts.DocumentRegistry,
             hasExplicitListOfFiles: boolean,
             compilerOptions: CompilerOptions,
-            private wildcardDirectories: Map<WatchDirectoryFlags>,
+            private wildcardDirectories: Map<string, WatchDirectoryFlags>,
             languageServiceEnabled: boolean,
             public compileOnSaveEnabled: boolean) {
             super(ProjectKind.Configured, projectService, documentRegistry, hasExplicitListOfFiles, languageServiceEnabled, compilerOptions, compileOnSaveEnabled);
@@ -648,18 +646,19 @@ namespace ts.server {
                 return;
             }
             const configDirectoryPath = getDirectoryPath(this.configFileName);
-            this.directoriesWatchedForWildcards = reduceProperties(this.wildcardDirectories, (watchers, flag, directory) => {
+
+            this.directoriesWatchedForWildcards = new StringMap<FileWatcher>();
+            this.wildcardDirectories.forEach((flag, directory) => {
                 if (comparePaths(configDirectoryPath, directory, ".", !this.projectService.host.useCaseSensitiveFileNames) !== Comparison.EqualTo) {
                     const recursive = (flag & WatchDirectoryFlags.Recursive) !== 0;
                     this.projectService.logger.info(`Add ${recursive ? "recursive " : ""}watcher for: ${directory}`);
-                    watchers[directory] = this.projectService.host.watchDirectory(
+                    this.directoriesWatchedForWildcards.set(directory, this.projectService.host.watchDirectory(
                         directory,
                         path => callback(this, path),
                         recursive
-                    );
+                    ));
                 }
-                return watchers;
-            }, <Map<FileWatcher>>{});
+            });
         }
 
         stopWatchingDirectory() {
@@ -683,9 +682,7 @@ namespace ts.server {
                 this.typeRootsWatchers = undefined;
             }
 
-            for (const id in this.directoriesWatchedForWildcards) {
-                this.directoriesWatchedForWildcards[id].close();
-            }
+            this.directoriesWatchedForWildcards.forEach(watcher => { watcher.close(); });
             this.directoriesWatchedForWildcards = undefined;
 
             this.stopWatchingDirectory();
diff --git a/src/server/scriptInfo.ts b/src/server/scriptInfo.ts
index 410382a9ca4ff..e974f28c1155a 100644
--- a/src/server/scriptInfo.ts
+++ b/src/server/scriptInfo.ts
@@ -4,7 +4,7 @@ namespace ts.server {
 
     export class ScriptInfo {
         /**
-         * All projects that include this file 
+         * All projects that include this file
          */
         readonly containingProjects: Project[] = [];
         private formatCodeSettings: ts.FormatCodeSettings;
@@ -96,7 +96,7 @@ namespace ts.server {
                 if (!this.formatCodeSettings) {
                     this.formatCodeSettings = getDefaultFormatCodeSettings(this.host);
                 }
-                mergeMaps(this.formatCodeSettings, formatSettings);
+                mergeMapLikes(this.formatCodeSettings, formatSettings);
             }
         }
 
diff --git a/src/server/session.ts b/src/server/session.ts
index edb79e3a0efc1..957258e3072b7 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -547,7 +547,7 @@ namespace ts.server {
                 const scriptInfo = this.projectService.getScriptInfo(args.file);
                 projects = scriptInfo.containingProjects;
             }
-            // ts.filter handles case when 'projects' is undefined 
+            // ts.filter handles case when 'projects' is undefined
             projects = filter(projects, p => p.languageServiceEnabled);
             if (!projects || !projects.length) {
                 return Errors.ThrowNoProject();
@@ -1279,7 +1279,7 @@ namespace ts.server {
             return { response, responseRequired: true };
         }
 
-        private handlers = createMap<(request: protocol.Request) => { response?: any, responseRequired?: boolean }>({
+        private handlers = mapOfMapLike<(request: protocol.Request) => { response?: any, responseRequired?: boolean }>({
             [CommandNames.OpenExternalProject]: (request: protocol.OpenExternalProjectRequest) => {
                 this.projectService.openExternalProject(request.arguments);
                 // TODO: report errors
@@ -1525,14 +1525,14 @@ namespace ts.server {
         });
 
         public addProtocolHandler(command: string, handler: (request: protocol.Request) => { response?: any, responseRequired: boolean }) {
-            if (command in this.handlers) {
+            if (this.handlers.has(command)) {
                 throw new Error(`Protocol handler already exists for command "${command}"`);
             }
-            this.handlers[command] = handler;
+            this.handlers.set(command, handler);
         }
 
         public executeCommand(request: protocol.Request): { response?: any, responseRequired?: boolean } {
-            const handler = this.handlers[request.command];
+            const handler = this.handlers.get(request.command);
             if (handler) {
                 return handler(request);
             }
diff --git a/src/server/tsconfig.library.json b/src/server/tsconfig.library.json
index a450b591a7e96..6ee6b5a6630a2 100644
--- a/src/server/tsconfig.library.json
+++ b/src/server/tsconfig.library.json
@@ -15,7 +15,7 @@
         "utilities.ts",
         "scriptVersionCache.ts",
         "scriptInfo.ts",
-        "lshost.ts",
+        "lsHost.ts",
         "typingsCache.ts",
         "project.ts",
         "editorServices.ts",
diff --git a/src/server/typingsCache.ts b/src/server/typingsCache.ts
index 889cfe1fb8f67..edca4230afeb0 100644
--- a/src/server/typingsCache.ts
+++ b/src/server/typingsCache.ts
@@ -29,21 +29,22 @@ namespace ts.server {
         if ((arr1 || emptyArray).length === 0 && (arr2 || emptyArray).length === 0) {
             return true;
         }
-        const set: Map<boolean> = createMap<boolean>();
+        const set = new StringMap<boolean>();
         let unique = 0;
 
         for (const v of arr1) {
-            if (set[v] !== true) {
-                set[v] = true;
+            if (set.get(v) !== true) {
+                set.set(v, true);
                 unique++;
             }
         }
         for (const v of arr2) {
-            if (!hasProperty(set, v)) {
+            const isSet = set.get(v);
+            if (isSet === undefined) {
                 return false;
             }
-            if (set[v] === true) {
-                set[v] = false;
+            if (isSet === true) {
+                set.set(v, false);
                 unique--;
             }
         }
@@ -71,7 +72,7 @@ namespace ts.server {
     }
 
     export class TypingsCache {
-        private readonly perProjectCache: Map<TypingsCacheEntry> = createMap<TypingsCacheEntry>();
+        private readonly perProjectCache = new StringMap<TypingsCacheEntry>();
 
         constructor(private readonly installer: ITypingsInstaller) {
         }
@@ -83,17 +84,17 @@ namespace ts.server {
                 return <any>emptyArray;
             }
 
-            const entry = this.perProjectCache[project.getProjectName()];
+            const entry = this.perProjectCache.get(project.getProjectName());
             const result: TypingsArray = entry ? entry.typings : <any>emptyArray;
             if (forceRefresh || !entry || typingOptionsChanged(typingOptions, entry.typingOptions) || compilerOptionsChanged(project.getCompilerOptions(), entry.compilerOptions)) {
                 // Note: entry is now poisoned since it does not really contain typings for a given combination of compiler options\typings options.
                 // instead it acts as a placeholder to prevent issuing multiple requests
-                this.perProjectCache[project.getProjectName()] = {
+                this.perProjectCache.set(project.getProjectName(), {
                     compilerOptions: project.getCompilerOptions(),
                     typingOptions,
                     typings: result,
                     poisoned: true
-                };
+                });
                 // something has been changed, issue a request to update typings
                 this.installer.enqueueInstallTypingsRequest(project, typingOptions);
             }
@@ -109,16 +110,16 @@ namespace ts.server {
         }
 
         updateTypingsForProject(projectName: string, compilerOptions: CompilerOptions, typingOptions: TypingOptions, newTypings: string[]) {
-            this.perProjectCache[projectName] = {
+            this.perProjectCache.set(projectName, {
                 compilerOptions,
                 typingOptions,
                 typings: toTypingsArray(newTypings),
                 poisoned: false
-            };
+            });
         }
 
         onProjectClosed(project: Project) {
-            delete this.perProjectCache[project.getProjectName()];
+            this.perProjectCache.delete(project.getProjectName());
             this.installer.onProjectClosed(project);
         }
     }
diff --git a/src/server/typingsInstaller/typingsInstaller.ts b/src/server/typingsInstaller/typingsInstaller.ts
index 0ed2ccce99d34..e574a4f7911b4 100644
--- a/src/server/typingsInstaller/typingsInstaller.ts
+++ b/src/server/typingsInstaller/typingsInstaller.ts
@@ -35,7 +35,7 @@ namespace ts.server.typingsInstaller {
 
     export const MaxPackageNameLength = 214;
     /**
-     * Validates package name using rules defined at https://docs.npmjs.com/files/package.json 
+     * Validates package name using rules defined at https://docs.npmjs.com/files/package.json
      */
     export function validatePackageName(packageName: string): PackageNameValidationResult {
         Debug.assert(!!packageName, "Package name is not specified");
@@ -75,10 +75,10 @@ namespace ts.server.typingsInstaller {
     };
 
     export abstract class TypingsInstaller {
-        private readonly packageNameToTypingLocation: Map<string> = createMap<string>();
-        private readonly missingTypingsSet: Map<true> = createMap<true>();
-        private readonly knownCachesSet: Map<true> = createMap<true>();
-        private readonly projectWatchers: Map<FileWatcher[]> = createMap<FileWatcher[]>();
+        private readonly packageNameToTypingLocation = new StringMap<string>();
+        private readonly missingTypingsSet = new StringSet();
+        private readonly knownCachesSet = new StringSet();
+        private readonly projectWatchers = new StringMap<FileWatcher[]>();
         readonly pendingRunRequests: PendingRequest[] = [];
 
         private installRunCount = 1;
@@ -109,7 +109,7 @@ namespace ts.server.typingsInstaller {
             if (this.log.isEnabled()) {
                 this.log.writeLine(`Closing file watchers for project '${projectName}'`);
             }
-            const watchers = this.projectWatchers[projectName];
+            const watchers = this.projectWatchers.get(projectName);
             if (!watchers) {
                 if (this.log.isEnabled()) {
                     this.log.writeLine(`No watchers are registered for project '${projectName}'`);
@@ -120,7 +120,7 @@ namespace ts.server.typingsInstaller {
                 w.close();
             }
 
-            delete this.projectWatchers[projectName];
+            this.projectWatchers.delete(projectName);
 
             if (this.log.isEnabled()) {
                 this.log.writeLine(`Closing file watchers for project '${projectName}' - done.`);
@@ -132,7 +132,7 @@ namespace ts.server.typingsInstaller {
                 this.log.writeLine(`Got install request ${JSON.stringify(req)}`);
             }
 
-            // load existing typing information from the cache 
+            // load existing typing information from the cache
             if (req.cachePath) {
                 if (this.log.isEnabled()) {
                     this.log.writeLine(`Request specifies cache path '${req.cachePath}', loading cached information...`);
@@ -174,7 +174,7 @@ namespace ts.server.typingsInstaller {
             if (this.log.isEnabled()) {
                 this.log.writeLine(`Processing cache location '${cacheLocation}'`);
             }
-            if (this.knownCachesSet[cacheLocation]) {
+            if (this.knownCachesSet.has(cacheLocation)) {
                 if (this.log.isEnabled()) {
                     this.log.writeLine(`Cache location was already processed...`);
                 }
@@ -200,7 +200,7 @@ namespace ts.server.typingsInstaller {
                         if (!typingFile) {
                             continue;
                         }
-                        const existingTypingFile = this.packageNameToTypingLocation[packageName];
+                        const existingTypingFile = this.packageNameToTypingLocation.get(packageName);
                         if (existingTypingFile === typingFile) {
                             continue;
                         }
@@ -212,14 +212,14 @@ namespace ts.server.typingsInstaller {
                         if (this.log.isEnabled()) {
                             this.log.writeLine(`Adding entry into typings cache: '${packageName}' => '${typingFile}'`);
                         }
-                        this.packageNameToTypingLocation[packageName] = typingFile;
+                        this.packageNameToTypingLocation.set(packageName, typingFile);
                     }
                 }
             }
             if (this.log.isEnabled()) {
                 this.log.writeLine(`Finished processing cache location '${cacheLocation}'`);
             }
-            this.knownCachesSet[cacheLocation] = true;
+            this.knownCachesSet.add(cacheLocation);
         }
 
         private filterTypings(typingsToInstall: string[]) {
@@ -228,7 +228,7 @@ namespace ts.server.typingsInstaller {
             }
             const result: string[] = [];
             for (const typing of typingsToInstall) {
-                if (this.missingTypingsSet[typing]) {
+                if (this.missingTypingsSet.has(typing)) {
                     continue;
                 }
                 const validationResult = validatePackageName(typing);
@@ -237,7 +237,7 @@ namespace ts.server.typingsInstaller {
                 }
                 else {
                     // add typing name to missing set so we won't process it again
-                    this.missingTypingsSet[typing] = true;
+                    this.missingTypingsSet.add(typing);
                     if (this.log.isEnabled()) {
                         switch (validationResult) {
                             case PackageNameValidationResult.NameTooLong:
@@ -291,20 +291,20 @@ namespace ts.server.typingsInstaller {
                 if (this.log.isEnabled()) {
                     this.log.writeLine(`Requested to install typings ${JSON.stringify(typingsToInstall)}, installed typings ${JSON.stringify(installedTypings)}`);
                 }
-                const installedPackages: Map<true> = createMap<true>();
+                const installedPackages = new StringSet();
                 const installedTypingFiles: string[] = [];
                 for (const t of installedTypings) {
                     const packageName = getBaseFileName(t);
                     if (!packageName) {
                         continue;
                     }
-                    installedPackages[packageName] = true;
+                    installedPackages.add(packageName);
                     const typingFile = typingToFileName(cachePath, packageName, this.installTypingHost);
                     if (!typingFile) {
                         continue;
                     }
-                    if (!this.packageNameToTypingLocation[packageName]) {
-                        this.packageNameToTypingLocation[packageName] = typingFile;
+                    if (!this.packageNameToTypingLocation.get(packageName)) {
+                        this.packageNameToTypingLocation.set(packageName, typingFile);
                     }
                     installedTypingFiles.push(typingFile);
                 }
@@ -312,11 +312,11 @@ namespace ts.server.typingsInstaller {
                     this.log.writeLine(`Installed typing files ${JSON.stringify(installedTypingFiles)}`);
                 }
                 for (const toInstall of typingsToInstall) {
-                    if (!installedPackages[toInstall]) {
+                    if (!installedPackages.has(toInstall)) {
                         if (this.log.isEnabled()) {
                             this.log.writeLine(`New missing typing package '${toInstall}'`);
                         }
-                        this.missingTypingsSet[toInstall] = true;
+                        this.missingTypingsSet.add(toInstall);
                     }
                 }
 
@@ -390,7 +390,7 @@ namespace ts.server.typingsInstaller {
                 });
                 watchers.push(w);
             }
-            this.projectWatchers[projectName] = watchers;
+            this.projectWatchers.set(projectName, watchers);
         }
 
         private createSetTypings(request: DiscoverTypings, typings: string[]): SetTypings {
diff --git a/src/server/utilities.ts b/src/server/utilities.ts
index 3f99da9977ea0..97bad9be9deb3 100644
--- a/src/server/utilities.ts
+++ b/src/server/utilities.ts
@@ -90,7 +90,7 @@ namespace ts.server {
         };
     }
 
-    export function mergeMaps(target: MapLike<any>, source: MapLike <any>): void {
+    export function mergeMapLikes(target: MapLike<any>, source: MapLike <any>): void {
         for (const key in source) {
             if (hasProperty(source, key)) {
                 target[key] = source[key];
@@ -131,32 +131,6 @@ namespace ts.server {
         return <NormalizedPath>fileName;
     }
 
-    export interface NormalizedPathMap<T> {
-        get(path: NormalizedPath): T;
-        set(path: NormalizedPath, value: T): void;
-        contains(path: NormalizedPath): boolean;
-        remove(path: NormalizedPath): void;
-    }
-
-    export function createNormalizedPathMap<T>(): NormalizedPathMap<T> {
-/* tslint:disable:no-null-keyword */
-        const map: Map<T> = Object.create(null);
-/* tslint:enable:no-null-keyword */
-        return {
-            get(path) {
-                return map[path];
-            },
-            set(path, value) {
-                map[path] = value;
-            },
-            contains(path) {
-                return hasProperty(map, path);
-            },
-            remove(path) {
-                delete map[path];
-            }
-        };
-    }
     function throwLanguageServiceIsDisabledError() {
         throw new Error("LanguageService is disabled");
     }
@@ -223,7 +197,7 @@ namespace ts.server {
          * these fields can be present in the project file
          **/
         files?: string[];
-        wildcardDirectories?: Map<WatchDirectoryFlags>;
+        wildcardDirectories?: MapLike<WatchDirectoryFlags>;
         compilerOptions?: CompilerOptions;
         typingOptions?: TypingOptions;
         compileOnSave?: boolean;
@@ -239,21 +213,22 @@ namespace ts.server {
     }
 
     export class ThrottledOperations {
-        private pendingTimeouts: Map<any> = createMap<any>();
+        private pendingTimeouts = new StringMap<any>();
         constructor(private readonly host: ServerHost) {
         }
 
         public schedule(operationId: string, delay: number, cb: () => void) {
-            if (hasProperty(this.pendingTimeouts, operationId)) {
+            const pendingTimeout = this.pendingTimeouts.get(operationId);
+            if (pendingTimeout !== undefined) {
                 // another operation was already scheduled for this id - cancel it
-                this.host.clearTimeout(this.pendingTimeouts[operationId]);
+                this.host.clearTimeout(pendingTimeout);
             }
-            // schedule new operation, pass arguments  
-            this.pendingTimeouts[operationId] = this.host.setTimeout(ThrottledOperations.run, delay, this, operationId, cb);
+            // schedule new operation, pass arguments
+            this.pendingTimeouts.set(operationId, this.host.setTimeout(ThrottledOperations.run, delay, this, operationId, cb));
         }
 
         private static run(self: ThrottledOperations, operationId: string, cb: () => void) {
-            delete self.pendingTimeouts[operationId];
+            self.pendingTimeouts.delete(operationId);
             cb();
         }
     }
diff --git a/src/services/classifier.ts b/src/services/classifier.ts
index c22aec6a78655..553d184eb9560 100644
--- a/src/services/classifier.ts
+++ b/src/services/classifier.ts
@@ -462,7 +462,7 @@ namespace ts {
     }
 
     /* @internal */
-    export function getSemanticClassifications(typeChecker: TypeChecker, cancellationToken: CancellationToken, sourceFile: SourceFile, classifiableNames: Map<string>, span: TextSpan): ClassifiedSpan[] {
+    export function getSemanticClassifications(typeChecker: TypeChecker, cancellationToken: CancellationToken, sourceFile: SourceFile, classifiableNames: Set<string>, span: TextSpan): ClassifiedSpan[] {
         return convertClassifications(getEncodedSemanticClassifications(typeChecker, cancellationToken, sourceFile, classifiableNames, span));
     }
 
@@ -487,7 +487,7 @@ namespace ts {
     }
 
     /* @internal */
-    export function getEncodedSemanticClassifications(typeChecker: TypeChecker, cancellationToken: CancellationToken, sourceFile: SourceFile, classifiableNames: Map<string>, span: TextSpan): Classifications {
+    export function getEncodedSemanticClassifications(typeChecker: TypeChecker, cancellationToken: CancellationToken, sourceFile: SourceFile, classifiableNames: Set<string>, span: TextSpan): Classifications {
         const result: number[] = [];
         processNode(sourceFile);
 
@@ -557,7 +557,7 @@ namespace ts {
                     // Only bother calling into the typechecker if this is an identifier that
                     // could possibly resolve to a type name.  This makes classification run
                     // in a third of the time it would normally take.
-                    if (classifiableNames[identifier.text]) {
+                    if (classifiableNames.has(identifier.text)) {
                         const symbol = typeChecker.getSymbolAtLocation(node);
                         if (symbol) {
                             const type = classifySymbol(symbol, getMeaningFromLocation(node));
diff --git a/src/services/completions.ts b/src/services/completions.ts
index 3fff0df5f9e28..c0560e011eb60 100644
--- a/src/services/completions.ts
+++ b/src/services/completions.ts
@@ -58,18 +58,17 @@ namespace ts.Completions {
 
         return { isGlobalCompletion, isMemberCompletion, isNewIdentifierLocation: isNewIdentifierLocation, entries };
 
-        function getJavaScriptCompletionEntries(sourceFile: SourceFile, position: number, uniqueNames: Map<string>): CompletionEntry[] {
+        function getJavaScriptCompletionEntries(sourceFile: SourceFile, position: number, uniqueNames: Set<string>): CompletionEntry[] {
             const entries: CompletionEntry[] = [];
 
-            const nameTable = getNameTable(sourceFile);
-            for (const name in nameTable) {
+            getNameTable(sourceFile).forEach((nameTablePosition, name) => {
                 // Skip identifiers produced only from the current location
-                if (nameTable[name] === position) {
-                    continue;
+                if (nameTablePosition === position) {
+                    return;
                 }
 
-                if (!uniqueNames[name]) {
-                    uniqueNames[name] = name;
+                if (!uniqueNames.has(name)) {
+                    uniqueNames.add(name);
                     const displayName = getCompletionEntryDisplayName(unescapeIdentifier(name), compilerOptions.target, /*performCharacterChecks*/ true);
                     if (displayName) {
                         const entry = {
@@ -81,7 +80,7 @@ namespace ts.Completions {
                         entries.push(entry);
                     }
                 }
-            }
+            });
 
             return entries;
         }
@@ -112,17 +111,17 @@ namespace ts.Completions {
 
         }
 
-        function getCompletionEntriesFromSymbols(symbols: Symbol[], entries: CompletionEntry[], location: Node, performCharacterChecks: boolean): Map<string> {
+        function getCompletionEntriesFromSymbols(symbols: Symbol[], entries: CompletionEntry[], location: Node, performCharacterChecks: boolean): Set<string> {
             const start = timestamp();
-            const uniqueNames = createMap<string>();
+            const uniqueNames = new StringSet();
             if (symbols) {
                 for (const symbol of symbols) {
                     const entry = createCompletionEntry(symbol, location, performCharacterChecks);
                     if (entry) {
                         const id = escapeIdentifier(entry.name);
-                        if (!uniqueNames[id]) {
+                        if (!uniqueNames.has(id)) {
                             entries.push(entry);
-                            uniqueNames[id] = id;
+                            uniqueNames.add(id);
                         }
                     }
                 }
@@ -343,7 +342,7 @@ namespace ts.Completions {
                 const files = tryReadDirectory(host, baseDirectory, extensions, /*exclude*/undefined, /*include*/["./*"]);
 
                 if (files) {
-                    const foundFiles = createMap<boolean>();
+                    const foundFiles = new StringSet();
                     for (let filePath of files) {
                         filePath = normalizePath(filePath);
                         if (exclude && comparePaths(filePath, exclude, scriptPath, ignoreCase) === Comparison.EqualTo) {
@@ -352,14 +351,14 @@ namespace ts.Completions {
 
                         const foundFileName = includeExtensions ? getBaseFileName(filePath) : removeFileExtension(getBaseFileName(filePath));
 
-                        if (!foundFiles[foundFileName]) {
-                            foundFiles[foundFileName] = true;
+                        if (!foundFiles.has(foundFileName)) {
+                            foundFiles.add(foundFileName);
                         }
                     }
 
-                    for (const foundFile in foundFiles) {
+                    foundFiles.forEach(foundFile => {
                         result.push(createCompletionEntryForModule(foundFile, ScriptElementKind.scriptElement, span));
-                    }
+                    });
                 }
 
                 // If possible, get folder completion as well
@@ -397,7 +396,7 @@ namespace ts.Completions {
 
                 if (paths) {
                     for (const path in paths) {
-                        if (paths.hasOwnProperty(path)) {
+                        if (hasProperty(paths, path)) {
                             if (path === "*") {
                                 if (paths[path]) {
                                     for (const pattern of paths[path]) {
@@ -1521,7 +1520,7 @@ namespace ts.Completions {
          *          do not occur at the current position and have not otherwise been typed.
          */
         function filterNamedImportOrExportCompletionItems(exportsOfModule: Symbol[], namedImportsOrExports: ImportOrExportSpecifier[]): Symbol[] {
-            const existingImportsOrExports = createMap<boolean>();
+            const existingImportsOrExports = new StringSet();
 
             for (const element of namedImportsOrExports) {
                 // If this is the current item we are editing right now, do not filter it out
@@ -1530,14 +1529,14 @@ namespace ts.Completions {
                 }
 
                 const name = element.propertyName || element.name;
-                existingImportsOrExports[name.text] = true;
+                existingImportsOrExports.add(name.text);
             }
 
-            if (!someProperties(existingImportsOrExports)) {
+            if (setIsEmpty(existingImportsOrExports)) {
                 return filter(exportsOfModule, e => e.name !== "default");
             }
 
-            return filter(exportsOfModule, e => e.name !== "default" && !existingImportsOrExports[e.name]);
+            return filter(exportsOfModule, e => e.name !== "default" && !existingImportsOrExports.has(e.name));
         }
 
         /**
@@ -1551,7 +1550,7 @@ namespace ts.Completions {
                 return contextualMemberSymbols;
             }
 
-            const existingMemberNames = createMap<boolean>();
+            const existingMemberNames = new StringSet();
             for (const m of existingMembers) {
                 // Ignore omitted expressions for missing members
                 if (m.kind !== SyntaxKind.PropertyAssignment &&
@@ -1581,10 +1580,10 @@ namespace ts.Completions {
                     existingName = (<Identifier>m.name).text;
                 }
 
-                existingMemberNames[existingName] = true;
+                existingMemberNames.add(existingName);
             }
 
-            return filter(contextualMemberSymbols, m => !existingMemberNames[m.name]);
+            return filter(contextualMemberSymbols, m => !existingMemberNames.has(m.name));
         }
 
         /**
@@ -1594,7 +1593,7 @@ namespace ts.Completions {
          *          do not occur at the current position and have not otherwise been typed.
          */
         function filterJsxAttributes(symbols: Symbol[], attributes: NodeArray<JsxAttribute | JsxSpreadAttribute>): Symbol[] {
-            const seenNames = createMap<boolean>();
+            const seenNames = new StringSet();
             for (const attr of attributes) {
                 // If this is the current item we are editing right now, do not filter it out
                 if (attr.getStart() <= position && position <= attr.getEnd()) {
@@ -1602,11 +1601,11 @@ namespace ts.Completions {
                 }
 
                 if (attr.kind === SyntaxKind.JsxAttribute) {
-                    seenNames[(<JsxAttribute>attr).name.text] = true;
+                    seenNames.add((<JsxAttribute>attr).name.text);
                 }
             }
 
-            return filter(symbols, a => !seenNames[a.name]);
+            return filter(symbols, a => !seenNames.has(a.name));
         }
     }
 
diff --git a/src/services/documentHighlights.ts b/src/services/documentHighlights.ts
index 0f18427e56885..d2c9ff5df7f34 100644
--- a/src/services/documentHighlights.ts
+++ b/src/services/documentHighlights.ts
@@ -39,16 +39,16 @@ namespace ts.DocumentHighlights {
                     return undefined;
                 }
 
-                const fileNameToDocumentHighlights = createMap<DocumentHighlights>();
+                const fileNameToDocumentHighlights = new StringMap<DocumentHighlights>();
                 const result: DocumentHighlights[] = [];
                 for (const referencedSymbol of referencedSymbols) {
                     for (const referenceEntry of referencedSymbol.references) {
                         const fileName = referenceEntry.fileName;
-                        let documentHighlights = fileNameToDocumentHighlights[fileName];
+                        let documentHighlights = fileNameToDocumentHighlights.get(fileName);
                         if (!documentHighlights) {
                             documentHighlights = { fileName, highlightSpans: [] };
 
-                            fileNameToDocumentHighlights[fileName] = documentHighlights;
+                            fileNameToDocumentHighlights.set(fileName, documentHighlights);
                             result.push(documentHighlights);
                         }
 
diff --git a/src/services/documentRegistry.ts b/src/services/documentRegistry.ts
index d73e4d3b0a125..7179daeae3a50 100644
--- a/src/services/documentRegistry.ts
+++ b/src/services/documentRegistry.ts
@@ -105,7 +105,7 @@ namespace ts {
     export function createDocumentRegistry(useCaseSensitiveFileNames?: boolean, currentDirectory = ""): DocumentRegistry {
         // Maps from compiler setting target (ES3, ES5, etc.) to all the cached documents we have
         // for those settings.
-        const buckets = createMap<FileMap<DocumentRegistryEntry>>();
+        const buckets = new StringMap<FileMap<DocumentRegistryEntry>>();
         const getCanonicalFileName = createGetCanonicalFileName(!!useCaseSensitiveFileNames);
 
         function getKeyForCompilationSettings(settings: CompilerOptions): DocumentRegistryBucketKey {
@@ -113,30 +113,35 @@ namespace ts {
         }
 
         function getBucketForCompilationSettings(key: DocumentRegistryBucketKey, createIfMissing: boolean): FileMap<DocumentRegistryEntry> {
-            let bucket = buckets[key];
+            let bucket = buckets.get(key);
             if (!bucket && createIfMissing) {
-                buckets[key] = bucket = createFileMap<DocumentRegistryEntry>();
+                buckets.set(key, bucket = createFileMap<DocumentRegistryEntry>());
             }
             return bucket;
         }
 
         function reportStats() {
-            const bucketInfoArray = Object.keys(buckets).filter(name => name && name.charAt(0) === "_").map(name => {
-                const entries = buckets[name];
-                const sourceFiles: { name: string; refCount: number; references: string[]; }[] = [];
-                entries.forEachValue((key, entry) => {
-                    sourceFiles.push({
-                        name: key,
-                        refCount: entry.languageServiceRefCount,
-                        references: entry.owners.slice(0)
+            type Info = {
+                bucket: string;
+                sourceFiles: { name: string, refCount: number, references: string[] }[]
+            };
+
+            const bucketInfoArray: Info[] = [];
+            buckets.forEach((entries, name) => {
+                if (name && name.charAt(0) === "_") {
+                    const sourceFiles: { name: string; refCount: number; references: string[]; }[] = [];
+                    entries.forEachValue((key, entry) => {
+                        sourceFiles.push({
+                            name: key,
+                            refCount: entry.languageServiceRefCount,
+                            references: entry.owners
+                        });
                     });
-                });
-                sourceFiles.sort((x, y) => y.refCount - x.refCount);
-                return {
-                    bucket: name,
-                    sourceFiles
-                };
+                    sourceFiles.sort((x, y) => y.refCount - x.refCount);
+                    bucketInfoArray.push({ bucket: name, sourceFiles });
+                }
             });
+
             return JSON.stringify(bucketInfoArray, undefined, 2);
         }
 
diff --git a/src/services/findAllReferences.ts b/src/services/findAllReferences.ts
index dcda3e40b1a67..95bf9084d798e 100644
--- a/src/services/findAllReferences.ts
+++ b/src/services/findAllReferences.ts
@@ -96,7 +96,7 @@ namespace ts.FindAllReferences {
 
                 const nameTable = getNameTable(sourceFile);
 
-                if (nameTable[internedName] !== undefined) {
+                if (nameTable.get(internedName) !== undefined) {
                     result = result || [];
                     getReferencesInNode(sourceFile, symbol, declaredName, node, searchMeaning, findInStrings, findInComments, result, symbolToIndex);
                 }
@@ -378,7 +378,7 @@ namespace ts.FindAllReferences {
             const possiblePositions = getPossibleSymbolReferencePositions(sourceFile, searchText, start, container.getEnd());
 
             const parents = getParentSymbolsOfPropertyAccess();
-            const inheritsFromCache: Map<boolean> = createMap<boolean>();
+            const inheritsFromCache = new StringMap<boolean>();
 
             if (possiblePositions.length) {
                 // Build the set of symbols to search for, initially it has only the current symbol
@@ -501,14 +501,14 @@ namespace ts.FindAllReferences {
             function findOwnConstructorCalls(classSymbol: Symbol): Node[] {
                 const result: Node[] = [];
 
-                for (const decl of classSymbol.members["__constructor"].declarations) {
+                for (const decl of classSymbol.members.get("__constructor").declarations) {
                     Debug.assert(decl.kind === SyntaxKind.Constructor);
                     const ctrKeyword = decl.getChildAt(0);
                     Debug.assert(ctrKeyword.kind === SyntaxKind.ConstructorKeyword);
                     result.push(ctrKeyword);
                 }
 
-                forEachProperty(classSymbol.exports, member => {
+                classSymbol.exports.forEach(member => {
                     const decl = member.valueDeclaration;
                     if (decl && decl.kind === SyntaxKind.MethodDeclaration) {
                         const body = (<MethodDeclaration>decl).body;
@@ -528,7 +528,7 @@ namespace ts.FindAllReferences {
             /** Find references to `super` in the constructor of an extending class.  */
             function superConstructorAccesses(cls: ClassLikeDeclaration): Node[] {
                 const symbol = cls.symbol;
-                const ctr = symbol.members["__constructor"];
+                const ctr = symbol.members.get("__constructor");
                 if (!ctr) {
                     return [];
                 }
@@ -705,7 +705,7 @@ namespace ts.FindAllReferences {
          * @param parent        Another class or interface Symbol
          * @param cachedResults A map of symbol id pairs (i.e. "child,parent") to booleans indicating previous results
          */
-        function explicitlyInheritsFrom(child: Symbol, parent: Symbol, cachedResults: Map<boolean>): boolean {
+        function explicitlyInheritsFrom(child: Symbol, parent: Symbol, cachedResults: Map<string, boolean>): boolean {
             const parentIsInterface = parent.getFlags() & SymbolFlags.Interface;
             return searchHierarchy(child);
 
@@ -715,12 +715,13 @@ namespace ts.FindAllReferences {
                 }
 
                 const key = getSymbolId(symbol) + "," + getSymbolId(parent);
-                if (key in cachedResults) {
-                    return cachedResults[key];
+                const cachedResult = cachedResults.get(key);
+                if (cachedResult !== undefined) {
+                    return cachedResult;
                 }
 
                 // Set the key so that we don't infinitely recurse
-                cachedResults[key] = false;
+                cachedResults.set(key, false);
 
                 const inherits = forEach(symbol.getDeclarations(), declaration => {
                     if (isClassLike(declaration)) {
@@ -744,7 +745,7 @@ namespace ts.FindAllReferences {
                     return false;
                 });
 
-                cachedResults[key] = inherits;
+                cachedResults.set(key, inherits);
                 return inherits;
             }
 
@@ -1046,7 +1047,7 @@ namespace ts.FindAllReferences {
 
                 // Add symbol of properties/methods of the same name in base classes and implemented interfaces definitions
                 if (!implementations && rootSymbol.parent && rootSymbol.parent.flags & (SymbolFlags.Class | SymbolFlags.Interface)) {
-                    getPropertySymbolsFromBaseTypes(rootSymbol.parent, rootSymbol.getName(), result, /*previousIterationSymbolsCache*/ createMap<Symbol>());
+                    getPropertySymbolsFromBaseTypes(rootSymbol.parent, rootSymbol.getName(), result, /*previousIterationSymbolsCache*/ new StringMap<Symbol>());
                 }
             });
 
@@ -1078,7 +1079,7 @@ namespace ts.FindAllReferences {
             // the function will add any found symbol of the property-name, then its sub-routine will call
             // getPropertySymbolsFromBaseTypes again to walk up any base types to prevent revisiting already
             // visited symbol, interface "C", the sub-routine will pass the current symbol as previousIterationSymbol.
-            if (symbol.name in previousIterationSymbolsCache) {
+            if (previousIterationSymbolsCache.has(symbol.name)) {
                 return;
             }
 
@@ -1105,14 +1106,14 @@ namespace ts.FindAllReferences {
                         }
 
                         // Visit the typeReference as well to see if it directly or indirectly use that property
-                        previousIterationSymbolsCache[symbol.name] = symbol;
+                        previousIterationSymbolsCache.set(symbol.name, symbol);
                         getPropertySymbolsFromBaseTypes(type.symbol, propertyName, result, previousIterationSymbolsCache);
                     }
                 }
             }
         }
 
-        function getRelatedSymbol(searchSymbols: Symbol[], referenceSymbol: Symbol, referenceLocation: Node, searchLocationIsConstructor: boolean, parents: Symbol[] | undefined, cache: Map<boolean>): Symbol {
+        function getRelatedSymbol(searchSymbols: Symbol[], referenceSymbol: Symbol, referenceLocation: Node, searchLocationIsConstructor: boolean, parents: Symbol[] | undefined, cache: Map<string, boolean>): Symbol {
             if (contains(searchSymbols, referenceSymbol)) {
                 // If we are searching for constructor uses, they must be 'new' expressions.
                 return (!searchLocationIsConstructor || isNewExpressionTarget(referenceLocation)) && referenceSymbol;
@@ -1176,7 +1177,7 @@ namespace ts.FindAllReferences {
                     }
 
                     const result: Symbol[] = [];
-                    getPropertySymbolsFromBaseTypes(rootSymbol.parent, rootSymbol.getName(), result, /*previousIterationSymbolsCache*/ createMap<Symbol>());
+                    getPropertySymbolsFromBaseTypes(rootSymbol.parent, rootSymbol.getName(), result, /*previousIterationSymbolsCache*/ new StringMap<Symbol>());
                     return forEach(result, s => searchSymbols.indexOf(s) >= 0 ? s : undefined);
                 }
 
diff --git a/src/services/formatting/rules.ts b/src/services/formatting/rules.ts
index 2095f062bd103..215289159c289 100644
--- a/src/services/formatting/rules.ts
+++ b/src/services/formatting/rules.ts
@@ -4,7 +4,7 @@
 namespace ts.formatting {
     export class Rules {
         public getRuleName(rule: Rule) {
-            const o: ts.Map<any> = <any>this;
+            const o: ts.MapLike<any> = <any>this;
             for (const name in o) {
                 if (o[name] === rule) {
                     return name;
diff --git a/src/services/goToDefinition.ts b/src/services/goToDefinition.ts
index 4c005640d6ae8..d6ade7aed6bd9 100644
--- a/src/services/goToDefinition.ts
+++ b/src/services/goToDefinition.ts
@@ -14,7 +14,7 @@ namespace ts.GoToDefinition {
         // Type reference directives
         const typeReferenceDirective = findReferenceInPosition(sourceFile.typeReferenceDirectives, position);
         if (typeReferenceDirective) {
-            const referenceFile = program.getResolvedTypeReferenceDirectives()[typeReferenceDirective.fileName];
+            const referenceFile = program.getResolvedTypeReferenceDirectives().get(typeReferenceDirective.fileName);
             if (referenceFile && referenceFile.resolvedFileName) {
                 return [getDefinitionInfoForFileReference(typeReferenceDirective.fileName, referenceFile.resolvedFileName)];
             }
diff --git a/src/services/jsTyping.ts b/src/services/jsTyping.ts
index d50e26c61941b..8023cba86b19d 100644
--- a/src/services/jsTyping.ts
+++ b/src/services/jsTyping.ts
@@ -17,19 +17,19 @@ namespace ts.JsTyping {
 
     interface PackageJson {
         _requiredBy?: string[];
-        dependencies?: Map<string>;
-        devDependencies?: Map<string>;
+        dependencies?: MapLike<string>;
+        devDependencies?: MapLike<string>;
         name?: string;
-        optionalDependencies?: Map<string>;
-        peerDependencies?: Map<string>;
+        optionalDependencies?: MapLike<string>;
+        peerDependencies?: MapLike<string>;
         typings?: string;
     };
 
     // A map of loose file names to library names
     // that we are confident require typings
-    let safeList: Map<string>;
+    let safeList: Map<string, string>;
 
-    const EmptySafeList: Map<string> = createMap<string>();
+    const EmptySafeList = new StringMap<string>();
 
     /**
      * @param host is the object providing I/O related operations.
@@ -45,13 +45,13 @@ namespace ts.JsTyping {
         fileNames: string[],
         projectRootPath: Path,
         safeListPath: Path,
-        packageNameToTypingLocation: Map<string>,
+        packageNameToTypingLocation: Map<string, string>,
         typingOptions: TypingOptions,
         compilerOptions: CompilerOptions):
         { cachedTypingPaths: string[], newTypingNames: string[], filesToWatch: string[] } {
 
         // A typing name to typing file path mapping
-        const inferredTypings = createMap<string>();
+        const inferredTypings = new StringMap<string | undefined>();
 
         if (!typingOptions || !typingOptions.enableAutoDiscovery) {
             return { cachedTypingPaths: [], newTypingNames: [], filesToWatch: [] };
@@ -65,7 +65,7 @@ namespace ts.JsTyping {
 
         if (!safeList) {
             const result = readConfigFile(safeListPath, (path: string) => host.readFile(path));
-            safeList = result.config ? createMap<string>(result.config) : EmptySafeList;
+            safeList = result.config ? mapOfMapLike<string>(result.config) : EmptySafeList;
         }
 
         const filesToWatch: string[] = [];
@@ -94,27 +94,28 @@ namespace ts.JsTyping {
         getTypingNamesFromSourceFileNames(fileNames);
 
         // Add the cached typing locations for inferred typings that are already installed
-        for (const name in packageNameToTypingLocation) {
-            if (name in inferredTypings && !inferredTypings[name]) {
-                inferredTypings[name] = packageNameToTypingLocation[name];
+        packageNameToTypingLocation.forEach((typingLocation, name) => {
+            if (inferredTypings.has(name) && inferredTypings.get(name) === undefined) {
+                inferredTypings.set(name, typingLocation);
             }
-        }
+        });
 
         // Remove typings that the user has added to the exclude list
         for (const excludeTypingName of exclude) {
-            delete inferredTypings[excludeTypingName];
+            inferredTypings.delete(excludeTypingName);
         }
 
         const newTypingNames: string[] = [];
         const cachedTypingPaths: string[] = [];
-        for (const typing in inferredTypings) {
-            if (inferredTypings[typing] !== undefined) {
-                cachedTypingPaths.push(inferredTypings[typing]);
+
+        inferredTypings.forEach((inferredTyping, typing) => {
+            if (inferredTyping !== undefined) {
+                cachedTypingPaths.push(inferredTyping);
             }
             else {
                 newTypingNames.push(typing);
             }
-        }
+        });
         return { cachedTypingPaths, newTypingNames, filesToWatch };
 
         /**
@@ -126,8 +127,8 @@ namespace ts.JsTyping {
             }
 
             for (const typing of typingNames) {
-                if (!(typing in inferredTypings)) {
-                    inferredTypings[typing] = undefined;
+                if (!inferredTypings.has(typing)) {
+                    inferredTypings.set(typing, undefined);
                 }
             }
         }
@@ -167,7 +168,7 @@ namespace ts.JsTyping {
             const cleanedTypingNames = map(inferredTypingNames, f => f.replace(/((?:\.|-)min(?=\.|$))|((?:-|\.)\d+)/g, ""));
 
             if (safeList !== EmptySafeList) {
-                mergeTypings(filter(cleanedTypingNames, f => f in safeList));
+                mergeTypings(filter(cleanedTypingNames, f => safeList.has(f)));
             }
 
             const hasJsxFile = forEach(fileNames, f => ensureScriptKind(f, getScriptKindFromFileName(f)) === ScriptKind.JSX);
@@ -214,7 +215,7 @@ namespace ts.JsTyping {
                 }
                 if (packageJson.typings) {
                     const absolutePath = getNormalizedAbsolutePath(packageJson.typings, getDirectoryPath(normalizedFileName));
-                    inferredTypings[packageJson.name] = absolutePath;
+                    inferredTypings.set(packageJson.name, absolutePath);
                 }
                 else {
                     typingNames.push(packageJson.name);
diff --git a/src/services/navigateTo.ts b/src/services/navigateTo.ts
index 44aa25f500572..0e5f9f9741696 100644
--- a/src/services/navigateTo.ts
+++ b/src/services/navigateTo.ts
@@ -10,23 +10,22 @@ namespace ts.NavigateTo {
         const baseSensitivity: Intl.CollatorOptions = { sensitivity: "base" };
 
         // Search the declarations in all files and output matched NavigateToItem into array of NavigateToItem[]
-        forEach(sourceFiles, sourceFile => {
+        for (const sourceFile of sourceFiles) {
             cancellationToken.throwIfCancellationRequested();
 
             if (excludeDtsFiles && fileExtensionIs(sourceFile.fileName, ".d.ts")) {
-                return;
+                continue;
             }
 
-            const nameToDeclarations = sourceFile.getNamedDeclarations();
-            for (const name in nameToDeclarations) {
-                const declarations = nameToDeclarations[name];
+            // Use `someInMap` to break out early.
+            someInMap(sourceFile.getNamedDeclarations(), (declarations, name) => {
                 if (declarations) {
                     // First do a quick check to see if the name of the declaration matches the
                     // last portion of the (possibly) dotted name they're searching for.
                     let matches = patternMatcher.getMatchesForLastSegmentOfPattern(name);
 
                     if (!matches) {
-                        continue;
+                        return false;
                     }
 
                     for (const declaration of declarations) {
@@ -35,13 +34,13 @@ namespace ts.NavigateTo {
                         if (patternMatcher.patternContainsDots) {
                             const containers = getContainers(declaration);
                             if (!containers) {
-                                return undefined;
+                                return true; // Go to the next source file.
                             }
 
                             matches = patternMatcher.getMatches(containers, name);
 
                             if (!matches) {
-                                continue;
+                                return false;
                             }
                         }
 
@@ -50,8 +49,8 @@ namespace ts.NavigateTo {
                         rawItems.push({ name, fileName, matchKind, isCaseSensitive: allMatchesAreCaseSensitive(matches), declaration });
                     }
                 }
-            }
-        });
+            });
+        }
 
         // Remove imports when the imported declaration is already in the list and has the same name.
         rawItems = filter(rawItems, item => {
diff --git a/src/services/navigationBar.ts b/src/services/navigationBar.ts
index 5c8c47e96665a..f3b91068d9462 100644
--- a/src/services/navigationBar.ts
+++ b/src/services/navigationBar.ts
@@ -232,7 +232,7 @@ namespace ts.NavigationBar {
 
     /** Merge declarations of the same kind. */
     function mergeChildren(children: NavigationBarNode[]): void {
-        const nameToItems = createMap<NavigationBarNode | NavigationBarNode[]>();
+        const nameToItems = new StringMap<NavigationBarNode | NavigationBarNode[]>();
         filterMutate(children, child => {
             const decl = <Declaration>child.node;
             const name = decl.name && nodeText(decl.name);
@@ -241,9 +241,9 @@ namespace ts.NavigationBar {
                 return true;
             }
 
-            const itemsWithSameName = nameToItems[name];
+            const itemsWithSameName = nameToItems.get(name);
             if (!itemsWithSameName) {
-                nameToItems[name] = child;
+                nameToItems.set(name, child);
                 return true;
             }
 
@@ -261,7 +261,7 @@ namespace ts.NavigationBar {
                 if (tryMerge(itemWithSameName, child)) {
                     return false;
                 }
-                nameToItems[name] = [itemWithSameName, child];
+                nameToItems.set(name, [itemWithSameName, child]);
                 return true;
             }
 
diff --git a/src/services/patternMatcher.ts b/src/services/patternMatcher.ts
index b4f67ca056ddb..ec7a2bbfa124f 100644
--- a/src/services/patternMatcher.ts
+++ b/src/services/patternMatcher.ts
@@ -113,7 +113,7 @@ namespace ts {
         // we see the name of a module that is used everywhere, or the name of an overload).  As
         // such, we cache the information we compute about the candidate for the life of this
         // pattern matcher so we don't have to compute it multiple times.
-        const stringToWordSpans = createMap<TextSpan[]>();
+        const stringToWordSpans = new StringMap<TextSpan[]>();
 
         pattern = pattern.trim();
 
@@ -188,11 +188,7 @@ namespace ts {
         }
 
         function getWordSpans(word: string): TextSpan[] {
-            if (!(word in stringToWordSpans)) {
-                stringToWordSpans[word] = breakIntoWordSpans(word);
-            }
-
-            return stringToWordSpans[word];
+            return getOrUpdate(stringToWordSpans, word, breakIntoWordSpans);
         }
 
         function matchTextChunk(candidate: string, chunk: TextChunk, punctuationStripped: boolean): PatternMatch {
diff --git a/src/services/services.ts b/src/services/services.ts
index e98e63f926ede..7e96e17003eeb 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -456,13 +456,13 @@ namespace ts {
         public scriptKind: ScriptKind;
         public languageVersion: ScriptTarget;
         public languageVariant: LanguageVariant;
-        public identifiers: Map<string>;
-        public nameTable: Map<number>;
-        public resolvedModules: Map<ResolvedModule>;
-        public resolvedTypeReferenceDirectiveNames: Map<ResolvedTypeReferenceDirective>;
+        public identifiers: Map<string, string>;
+        public nameTable: Map<string, number>;
+        public resolvedModules: Map<string, ResolvedModule>;
+        public resolvedTypeReferenceDirectiveNames: Map<string, ResolvedTypeReferenceDirective>;
         public imports: LiteralExpression[];
         public moduleAugmentations: LiteralExpression[];
-        private namedDeclarations: Map<Declaration[]>;
+        private namedDeclarations: Map<string, Declaration[]>;
 
         constructor(kind: SyntaxKind, pos: number, end: number) {
             super(kind, pos, end);
@@ -484,7 +484,7 @@ namespace ts {
             return ts.getPositionOfLineAndCharacter(this, line, character);
         }
 
-        public getNamedDeclarations(): Map<Declaration[]> {
+        public getNamedDeclarations(): Map<string, Declaration[]> {
             if (!this.namedDeclarations) {
                 this.namedDeclarations = this.computeNamedDeclarations();
             }
@@ -492,8 +492,8 @@ namespace ts {
             return this.namedDeclarations;
         }
 
-        private computeNamedDeclarations(): Map<Declaration[]> {
-            const result = createMap<Declaration[]>();
+        private computeNamedDeclarations(): Map<string, Declaration[]> {
+            const result = new StringMap<Declaration[]>();
 
             forEachChild(this, visit);
 
@@ -507,7 +507,7 @@ namespace ts {
             }
 
             function getDeclarations(name: string) {
-                return result[name] || (result[name] = []);
+                return getOrUpdate(result, name, () => []);
             }
 
             function getDeclarationName(declaration: Declaration) {
@@ -953,7 +953,7 @@ namespace ts {
         const currentDirectory = host.getCurrentDirectory();
         // Check if the localized messages json is set, otherwise query the host for it
         if (!localizedDiagnosticMessages && host.getLocalizedDiagnosticMessages) {
-            localizedDiagnosticMessages = host.getLocalizedDiagnosticMessages();
+            localizedDiagnosticMessages = mapOfMapLike<string>(host.getLocalizedDiagnosticMessages());
         }
 
         function log(message: string) {
@@ -1876,7 +1876,7 @@ namespace ts {
     }
 
     /* @internal */
-    export function getNameTable(sourceFile: SourceFile): Map<number> {
+    export function getNameTable(sourceFile: SourceFile): Map<string, number> {
         if (!sourceFile.nameTable) {
             initializeNameTable(sourceFile);
         }
@@ -1885,7 +1885,7 @@ namespace ts {
     }
 
     function initializeNameTable(sourceFile: SourceFile): void {
-        const nameTable = createMap<number>();
+        const nameTable = new StringMap<number>();
 
         walk(sourceFile);
         sourceFile.nameTable = nameTable;
@@ -1893,7 +1893,7 @@ namespace ts {
         function walk(node: Node) {
             switch (node.kind) {
                 case SyntaxKind.Identifier:
-                    nameTable[(<Identifier>node).text] = nameTable[(<Identifier>node).text] === undefined ? node.pos : -1;
+                    nameTable.set((<Identifier>node).text, nameTable.get((<Identifier>node).text) === undefined ? node.pos : -1);
                     break;
                 case SyntaxKind.StringLiteral:
                 case SyntaxKind.NumericLiteral:
@@ -1906,7 +1906,7 @@ namespace ts {
                         isArgumentOfElementAccessExpression(node) ||
                         isLiteralComputedPropertyDeclarationName(node)) {
 
-                        nameTable[(<LiteralExpression>node).text] = nameTable[(<LiteralExpression>node).text] === undefined ? node.pos : -1;
+                        nameTable.set((<LiteralExpression>node).text, nameTable.get((<LiteralExpression>node).text) === undefined ? node.pos : -1);
                     }
                     break;
                 default:
diff --git a/src/services/shims.ts b/src/services/shims.ts
index 56ab852606cd7..b4fff2ee54cd9 100644
--- a/src/services/shims.ts
+++ b/src/services/shims.ts
@@ -1157,7 +1157,7 @@ namespace ts {
                     info.fileNames,
                     toPath(info.projectRootPath, info.projectRootPath, getCanonicalFileName),
                     toPath(info.safeListPath, info.safeListPath, getCanonicalFileName),
-                    info.packageNameToTypingLocation,
+                    mapOfMapLike(info.packageNameToTypingLocation),
                     info.typingOptions,
                     info.compilerOptions);
             });
diff --git a/src/services/signatureHelp.ts b/src/services/signatureHelp.ts
index 211e55b23ba5e..3562169ac7af6 100644
--- a/src/services/signatureHelp.ts
+++ b/src/services/signatureHelp.ts
@@ -237,7 +237,7 @@ namespace ts.SignatureHelp {
         const typeChecker = program.getTypeChecker();
         for (const sourceFile of program.getSourceFiles()) {
             const nameToDeclarations = sourceFile.getNamedDeclarations();
-            const declarations = nameToDeclarations[name.text];
+            const declarations = nameToDeclarations.get(name.text);
 
             if (declarations) {
                 for (const declaration of declarations) {
diff --git a/src/services/transpile.ts b/src/services/transpile.ts
index 303ca0d4173a2..4a8d5886ff693 100644
--- a/src/services/transpile.ts
+++ b/src/services/transpile.ts
@@ -63,7 +63,7 @@ namespace ts {
         }
 
         if (transpileOptions.renamedDependencies) {
-            sourceFile.renamedDependencies = createMap(transpileOptions.renamedDependencies);
+            sourceFile.renamedDependencies = mapOfMapLike(transpileOptions.renamedDependencies);
         }
 
         const newLine = getNewLineCharacter(options);
@@ -126,7 +126,7 @@ namespace ts {
     function fixupCompilerOptions(options: CompilerOptions, diagnostics: Diagnostic[]): CompilerOptions {
         // Lazily create this value to fix module loading errors.
         commandLineOptionsStringToEnum = commandLineOptionsStringToEnum || <CommandLineOptionOfCustomType[]>filter(optionDeclarations, o =>
-            typeof o.type === "object" && !forEachProperty(o.type, v => typeof v !== "number"));
+            typeof o.type === "object" && !someValueInMap(o.type, v => typeof v !== "number"));
 
         options = clone(options);
 
@@ -142,7 +142,7 @@ namespace ts {
                 options[opt.name] = parseCustomTypeOption(opt, value, diagnostics);
             }
             else {
-                if (!forEachProperty(opt.type, v => v === value)) {
+                if (!someValueInMap(opt.type, v => v === value)) {
                     // Supplied value isn't a valid enum value.
                     diagnostics.push(createCompilerDiagnosticForInvalidCustomType(opt));
                 }
diff --git a/src/services/types.ts b/src/services/types.ts
index f84986bb534e7..7b8a8f9b1666a 100644
--- a/src/services/types.ts
+++ b/src/services/types.ts
@@ -48,9 +48,9 @@ namespace ts {
     export interface SourceFile {
         /* @internal */ version: string;
         /* @internal */ scriptSnapshot: IScriptSnapshot;
-        /* @internal */ nameTable: Map<number>;
+        /* @internal */ nameTable: Map<string, number>;
 
-        /* @internal */ getNamedDeclarations(): Map<Declaration[]>;
+        /* @internal */ getNamedDeclarations(): Map<string, Declaration[]>;
 
         getLineAndCharacterOfPosition(pos: number): LineAndCharacter;
         getLineStarts(): number[];
diff --git a/tslint.json b/tslint.json
index 81990190ddbda..d33b87381c859 100644
--- a/tslint.json
+++ b/tslint.json
@@ -47,6 +47,7 @@
         "prefer-const": true,
         "no-increment-decrement": true,
         "object-literal-surrounding-space": true,
-        "no-type-assertion-whitespace": true
+        "no-type-assertion-whitespace": true,
+        "no-in-operator": true
   }
 }

From 3b7a1a8e22511946211c3cc86e0d2c071b552dc8 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Tue, 4 Oct 2016 08:46:48 -0700
Subject: [PATCH 022/224] Remove more uses of 'get'

---
 src/compiler/sys.ts                        |  2 +-
 src/compiler/transformers/module/module.ts |  6 +--
 src/harness/fourslash.ts                   |  3 +-
 src/harness/harness.ts                     |  7 ++-
 src/server/editorServices.ts               | 61 ++++++++++++----------
 5 files changed, 41 insertions(+), 38 deletions(-)

diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index 784c40f4d224d..4ec88f55736fd 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -301,7 +301,7 @@ namespace ts {
                     if ((eventName === "change" || eventName === "rename")) {
                         const callbacks = fileWatcherCallbacks.get(fileName);
                         if (callbacks) {
-                            for (const fileCallback of fileWatcherCallbacks.get(fileName)) {
+                            for (const fileCallback of callbacks) {
                                 fileCallback(fileName);
                            }
                         }
diff --git a/src/compiler/transformers/module/module.ts b/src/compiler/transformers/module/module.ts
index 284dbe852d180..4003e8ce78bd2 100644
--- a/src/compiler/transformers/module/module.ts
+++ b/src/compiler/transformers/module/module.ts
@@ -581,7 +581,7 @@ namespace ts {
         function addExportMemberAssignments(statements: Statement[], name: Identifier): void {
             const specifiers = !exportEquals && exportSpecifiers && exportSpecifiers.get(name.text);
             if (specifiers) {
-                for (const specifier of exportSpecifiers.get(name.text)) {
+                for (const specifier of specifiers) {
                     statements.push(
                         startOnNewLine(
                             createStatement(
@@ -672,7 +672,7 @@ namespace ts {
                 if (specifiers) {
                     const sourceFileId = getOriginalNodeId(currentSourceFile);
                     const bindingNameExportSpecifiers = getOrUpdate(bindingNameExportSpecifiersForFileMap, sourceFileId, () => new StringMap());
-                    bindingNameExportSpecifiers.set(name.text, exportSpecifiers.get(name.text));
+                    bindingNameExportSpecifiers.set(name.text, specifiers);
                     addExportMemberAssignments(resultStatements, name);
                 }
             }
@@ -926,7 +926,7 @@ namespace ts {
                         setEmitFlags(transformedUnaryExpression, EmitFlags.NoSubstitution);
                     }
                     let nestedExportAssignment: BinaryExpression;
-                    for (const specifier of bindingNameExportSpecifiersMap.get(operand.text)) {
+                    for (const specifier of bindingNameExportSpecifiers) {
                         nestedExportAssignment = nestedExportAssignment ?
                             createExportAssignment(specifier.name, nestedExportAssignment) :
                             createExportAssignment(specifier.name, transformedUnaryExpression || node);
diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index 7f6c1f47cbf38..eb957ae49d01e 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -700,7 +700,8 @@ namespace FourSlash {
             const uniqueItems = new ts.StringMap<string>();
             for (const item of completions.entries) {
                 if (!ts.setIfNotSet(uniqueItems, item.name, item.kind)) {
-                    assert.equal(item.kind, uniqueItems.get(item.name), `Items should have the same kind, got ${item.kind} and ${uniqueItems.get(item.name)}`);
+                    const uniqueItem = uniqueItems.get(item.name);
+                    assert.equal(item.kind, uniqueItem, `Items should have the same kind, got ${item.kind} and ${uniqueItem}`);
                 }
             }
         }
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index 7f471ba2b19e6..ab7133b94a454 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -933,10 +933,9 @@ namespace Harness {
                 return undefined;
             }
 
-            if (!libFileNameSourceFileMap.get(fileName)) {
-                libFileNameSourceFileMap.set(fileName, createSourceFileAndAssertInvariants(fileName, IO.readFile(libFolder + fileName), ts.ScriptTarget.Latest));
-            }
-            return libFileNameSourceFileMap.get(fileName);
+            const sourceFile = libFileNameSourceFileMap.get(fileName);
+            return sourceFile || ts.setAndReturn(libFileNameSourceFileMap, fileName,
+                createSourceFileAndAssertInvariants(fileName, IO.readFile(libFolder + fileName), ts.ScriptTarget.Latest));
         }
 
         export function getDefaultLibFileName(options: ts.CompilerOptions): string {
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index 5b0f2d81d3915..ebc7a389706f4 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -1238,40 +1238,43 @@ namespace ts.server {
                 // close existing project and later we'll open a set of configured projects for these files
                 this.closeExternalProject(proj.projectFileName, /*suppressRefresh*/ true);
             }
-            else if (this.externalProjectToConfiguredProjectMap.get(proj.projectFileName)) {
-                // this project used to include config files
-                if (!tsConfigFiles) {
-                    // config files were removed from the project - close existing external project which in turn will close configured projects
-                    this.closeExternalProject(proj.projectFileName, /*suppressRefresh*/ true);
-                }
-                else {
-                    // project previously had some config files - compare them with new set of files and close all configured projects that correspond to unused files
-                    const oldConfigFiles = this.externalProjectToConfiguredProjectMap.get(proj.projectFileName);
-                    let iNew = 0;
-                    let iOld = 0;
-                    while (iNew < tsConfigFiles.length && iOld < oldConfigFiles.length) {
-                        const newConfig = tsConfigFiles[iNew];
-                        const oldConfig = oldConfigFiles[iOld];
-                        if (oldConfig < newConfig) {
-                            this.closeConfiguredProject(oldConfig);
-                            iOld++;
-                        }
-                        else if (oldConfig > newConfig) {
-                            iNew++;
+            else  {
+                const oldConfigFiles = this.externalProjectToConfiguredProjectMap.get(proj.projectFileName);
+                if (oldConfigFiles) {
+                    // this project used to include config files
+                    if (!tsConfigFiles) {
+                        // config files were removed from the project - close existing external project which in turn will close configured projects
+                        this.closeExternalProject(proj.projectFileName, /*suppressRefresh*/ true);
+                    }
+                    else {
+                        // project previously had some config files - compare them with new set of files and close all configured projects that correspond to unused files
+                        let iNew = 0;
+                        let iOld = 0;
+                        while (iNew < tsConfigFiles.length && iOld < oldConfigFiles.length) {
+                            const newConfig = tsConfigFiles[iNew];
+                            const oldConfig = oldConfigFiles[iOld];
+                            if (oldConfig < newConfig) {
+                                this.closeConfiguredProject(oldConfig);
+                                iOld++;
+                            }
+                            else if (oldConfig > newConfig) {
+                                iNew++;
+                            }
+                            else {
+                                // record existing config files so avoid extra add-refs
+                                (exisingConfigFiles || (exisingConfigFiles = [])).push(oldConfig);
+                                iOld++;
+                                iNew++;
+                            }
                         }
-                        else {
-                            // record existing config files so avoid extra add-refs
-                            (exisingConfigFiles || (exisingConfigFiles = [])).push(oldConfig);
-                            iOld++;
-                            iNew++;
+                        for (let i = iOld; i < oldConfigFiles.length; i++) {
+                            // projects for all remaining old config files should be closed
+                            this.closeConfiguredProject(oldConfigFiles[i]);
                         }
                     }
-                    for (let i = iOld; i < oldConfigFiles.length; i++) {
-                        // projects for all remaining old config files should be closed
-                        this.closeConfiguredProject(oldConfigFiles[i]);
-                    }
                 }
             }
+
             if (tsConfigFiles) {
                 // store the list of tsconfig files that belong to the external project
                 this.externalProjectToConfiguredProjectMap.set(proj.projectFileName, tsConfigFiles);

From 2622331c9c216378d03a9473719e9adfcfd3e52c Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Wed, 5 Oct 2016 07:58:03 -0700
Subject: [PATCH 023/224] Add heap performance markers

---
 src/compiler/checker.ts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 941bfdfac8bbd..78408e13af712 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -19223,6 +19223,8 @@ namespace ts {
 
         function initializeTypeChecker() {
             // Bind all source files and propagate errors
+            performance.mark("heapBeforeBind");
+
             for (const file of host.getSourceFiles()) {
                 bindSourceFile(file, compilerOptions);
             }
@@ -19272,6 +19274,8 @@ namespace ts {
             // Setup global builtins
             addToSymbolTable(globals, builtinGlobals, Diagnostics.Declaration_name_conflicts_with_built_in_global_identifier_0);
 
+            performance.mark("heapAfterBind");
+
             getSymbolLinks(undefinedSymbol).type = undefinedWideningType;
             getSymbolLinks(argumentsSymbol).type = getGlobalType("IArguments");
             getSymbolLinks(unknownSymbol).type = unknownType;

From 499ca7969c9d8469091b171e2f4f4b8ae714cf03 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Wed, 5 Oct 2016 10:57:16 -0700
Subject: [PATCH 024/224] Change the memberTypes of an EnumType to a (possibly
 sparse, but probably not ) array.

---
 src/compiler/checker.ts | 8 ++++----
 src/compiler/types.ts   | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 78408e13af712..e8d2bacac63ef 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -3868,15 +3868,15 @@ namespace ts {
                 enumType.symbol = symbol;
                 if (enumHasLiteralMembers(symbol)) {
                     const memberTypeList: Type[] = [];
-                    const memberTypes = new NumberMap<number, EnumLiteralType>();
+                    const memberTypes: { [enumMemberValue: number]: EnumLiteralType } = [];
                     for (const declaration of enumType.symbol.declarations) {
                         if (declaration.kind === SyntaxKind.EnumDeclaration) {
                             computeEnumMemberValues(<EnumDeclaration>declaration);
                             for (const member of (<EnumDeclaration>declaration).members) {
                                 const memberSymbol = getSymbolOfNode(member);
                                 const value = getEnumMemberValue(member);
-                                if (!memberTypes.get(value)) {
-                                    memberTypeList.push(setAndReturn(memberTypes, value, createEnumLiteralType(memberSymbol, enumType, "" + value)));
+                                if (!memberTypes[value]) {
+                                    memberTypeList.push(memberTypes[value] = createEnumLiteralType(memberSymbol, enumType, "" + value));
                                 }
                             }
                         }
@@ -3897,7 +3897,7 @@ namespace ts {
             if (!links.declaredType) {
                 const enumType = <EnumType>getDeclaredTypeOfEnum(getParentOfSymbol(symbol));
                 links.declaredType = enumType.flags & TypeFlags.Union ?
-                    enumType.memberTypes.get(getEnumMemberValue(<EnumDeclaration>symbol.valueDeclaration)) :
+                    enumType.memberTypes[getEnumMemberValue(<EnumDeclaration>symbol.valueDeclaration)] :
                     enumType;
             }
             return links.declaredType;
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 3a92904fd7e7d..1b180c923c112 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2483,7 +2483,7 @@ namespace ts {
 
     // Enum types (TypeFlags.Enum)
     export interface EnumType extends Type {
-        memberTypes: Map<number, EnumLiteralType>;
+        memberTypes: { [enumMemberValue: number]: EnumLiteralType };
     }
 
     // Enum types (TypeFlags.EnumLiteral)

From 5f401dac703536b0fb5109eab98242ebe9cd9804 Mon Sep 17 00:00:00 2001
From: Ron Buckton <rbuckton@microsoft.com>
Date: Thu, 6 Oct 2016 17:55:47 -0700
Subject: [PATCH 025/224] Fix lint warnings.

---
 src/compiler/core.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 439e56095664f..e81e4d470e295 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -448,7 +448,7 @@ namespace ts {
      * are not present in `arrayA` but are present in `arrayB`. Assumes both arrays are sorted
      * based on the provided comparer.
      */
-    export function relativeComplement<T>(arrayA: T[] | undefined, arrayB: T[] | undefined, comparer: (x: T, y: T) => Comparison = compareValues, offsetA: number = 0, offsetB: number = 0): T[] | undefined {
+    export function relativeComplement<T>(arrayA: T[] | undefined, arrayB: T[] | undefined, comparer: (x: T, y: T) => Comparison = compareValues, offsetA = 0, offsetB = 0): T[] | undefined {
         if (!arrayB || !arrayA || arrayB.length === 0 || arrayA.length === 0) return arrayB;
         const result: T[] = [];
         outer: for (; offsetB < arrayB.length; offsetB++) {

From 221054db5162b83304db760dfcee5949cd5d131d Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Fri, 7 Oct 2016 06:20:50 -0700
Subject: [PATCH 026/224] Respond to PR comments

---
 Jakefile.js                                        |  4 ++--
 src/compiler/{dataStructures.ts => collections.ts} | 12 ++++++------
 src/compiler/core.ts                               |  4 ++--
 src/compiler/tsconfig.json                         |  2 +-
 src/compiler/types.ts                              |  2 +-
 5 files changed, 12 insertions(+), 12 deletions(-)
 rename src/compiler/{dataStructures.ts => collections.ts} (95%)

diff --git a/Jakefile.js b/Jakefile.js
index 2e4a30c90c61a..e55933ac03dc5 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -57,7 +57,7 @@ function measure(marker) {
 }
 
 var compilerSources = [
-    "dataStructures.ts",
+    "collections.ts",
     "core.ts",
     "performance.ts",
     "sys.ts",
@@ -92,7 +92,7 @@ var compilerSources = [
 });
 
 var servicesSources = [
-    "dataStructures.ts",
+    "collections.ts",
     "core.ts",
     "performance.ts",
     "sys.ts",
diff --git a/src/compiler/dataStructures.ts b/src/compiler/collections.ts
similarity index 95%
rename from src/compiler/dataStructures.ts
rename to src/compiler/collections.ts
index 57874c0f6c1ba..e553363e380e6 100644
--- a/src/compiler/dataStructures.ts
+++ b/src/compiler/collections.ts
@@ -8,7 +8,7 @@ namespace ts {
     const fullyFeaturedMaps = usingNativeMaps && "keys" in Map.prototype && "values" in Map.prototype && "entries" in Map.prototype;
 
     /** Extra Map methods that may not be available, so we must provide fallbacks. */
-    interface FullyFeaturedMap<K, V> extends Map<K, V> {
+    interface ES6Map<K, V> extends Map<K, V> {
         keys(): Iterator<K>;
         values(): Iterator<V>;
         entries(): Iterator<[K, V]>;
@@ -122,7 +122,7 @@ namespace ts {
 
     /** Iterates over entries in the map, returning the first output of `getResult` that is not `undefined`. */
     export const findInMap: <K, V, U>(map: Map<K, V>, getResult: (value: V, key: K) => U | undefined) => U | undefined = fullyFeaturedMaps
-        ? <K, V, U>(map: FullyFeaturedMap<K, V>, f: (value: V, key: K) => U | undefined) => {
+        ? <K, V, U>(map: ES6Map<K, V>, f: (value: V, key: K) => U | undefined) => {
             const iter = map.entries();
             while (true) {
                 const { value: pair, done } = iter.next();
@@ -147,7 +147,7 @@ namespace ts {
 
     /** Whether `predicate` is true for at least one entry in the map. */
     export const someInMap: <K, V>(map: Map<K, V>, predicate: (value: V, key: K) => boolean) => boolean = fullyFeaturedMaps
-        ? <K, V>(map: FullyFeaturedMap<K, V>, predicate: (value: V, key: K) => boolean) =>
+        ? <K, V>(map: ES6Map<K, V>, predicate: (value: V, key: K) => boolean) =>
             someInIterator(map.entries(), ([key, value]) => predicate(value, key))
         : <K, V>(map: Map<K, V>, predicate: (value: V, key: K) => boolean) => {
             let found = false;
@@ -159,13 +159,13 @@ namespace ts {
 
     /** Whether `predicate` is true for at least one key in the map. */
     export const someKeyInMap: <K>(map: Map<K, any>, predicate: (key: K) => boolean) => boolean = fullyFeaturedMaps
-        ? <K>(map: FullyFeaturedMap<K, any>, predicate: (key: K) => boolean) => someInIterator(map.keys(), predicate)
+        ? <K>(map: ES6Map<K, any>, predicate: (key: K) => boolean) => someInIterator(map.keys(), predicate)
         : <K>(map: Map<K, any>, predicate: (key: K) => boolean) =>
             someInMap(map, (_value, key) => predicate(key));
 
     /** Whether `predicate` is true for at least one value in the map. */
     export const someValueInMap: <T>(map: Map<any, T>, predicate: (value: T) => boolean) => boolean = fullyFeaturedMaps
-        ? <T>(map: FullyFeaturedMap<any, T>, predicate: (value: T) => boolean) =>
+        ? <T>(map: ES6Map<any, T>, predicate: (value: T) => boolean) =>
             someInIterator(map.values(), predicate)
         : someInMap;
 
@@ -186,7 +186,7 @@ namespace ts {
      * `for (const key of map.keys()) action(key);`
      */
     export const forEachKeyInMap: <K>(map: Map<K, any>, action: (key: K) => void) => void = fullyFeaturedMaps
-        ? <K>(map: FullyFeaturedMap<K, any>, f: (key: K) => void) => {
+        ? <K>(map: ES6Map<K, any>, f: (key: K) => void) => {
             const iter: Iterator<K> = map.keys();
             while (true) {
                 const { value: key, done } = iter.next();
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 65cbae6a7d28f..8c06856d1b2bd 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -1,4 +1,4 @@
-/// <reference path="dataStructures.ts" />
+/// <reference path="collections.ts" />
 /// <reference path="types.ts"/>
 /// <reference path="performance.ts" />
 
@@ -916,7 +916,7 @@ namespace ts {
 
     /**
      * Returns the path except for its basename. Eg:
-     * 
+     *
      * /path/to/file.ext -> /path/to
      */
     export function getDirectoryPath(path: Path): Path;
diff --git a/src/compiler/tsconfig.json b/src/compiler/tsconfig.json
index 8dfa32b488486..19540367686a3 100644
--- a/src/compiler/tsconfig.json
+++ b/src/compiler/tsconfig.json
@@ -12,7 +12,7 @@
     },
     "files": [
         "core.ts",
-        "dataStructures.ts",
+        "collections.ts",
         "performance.ts",
         "sys.ts",
         "types.ts",
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 419971a865439..69061d42d6dc4 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -13,7 +13,7 @@ namespace ts {
      * Map can only be instantiated using NumberMap and StringMap, which come with shims.
      *
      * Internet Explorer does not support iterator-returning methods, so those are not allowed here.
-     * But map-using functions in dataStructures.ts check for these features and use them where possible.
+     * But map-using functions in collections.ts check for these features and use them where possible.
      */
     export interface Map<K, V> {
         clear(): void;

From d770c568743d6cc7ae6e5c21387ba8d0bb9d419f Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 7 Oct 2016 08:55:02 -0700
Subject: [PATCH 027/224] Switch spread types to a binary representation.

This allows much easier creation of spread types. Spread type creation
is now much smarter, and creates object types when possible. When
it's not, it produces a spread type that simplifies its input into a
standard structure for containing type parameters.

The spread type is no longer related to union or intersection types.
Spread types containing union and intersection types are not yet
correctly handled.
---
 src/compiler/checker.ts | 387 +++++++++++++++++++++++-----------------
 src/compiler/types.ts   |  21 ++-
 2 files changed, 232 insertions(+), 176 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 44784c4ab2320..0e7266b223ccd 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2310,33 +2310,40 @@ namespace ts {
                     writePunctuation(writer, SyntaxKind.OpenBraceToken);
                     writer.writeLine();
                     writer.increaseIndent();
-                    let printFollowingPunctuation = false;
-                    for (const t of type.types) {
-                        if (printFollowingPunctuation) {
-                            writePunctuation(writer, SyntaxKind.SemicolonToken);
-                            writer.writeLine();
-                        }
-                        if (t.isDeclaredProperty) {
-                            const saveInObjectTypeLiteral = inObjectTypeLiteral;
-                            inObjectTypeLiteral = true;
-                            writeObjectLiteralType(resolveStructuredTypeMembers(t));
-                            printFollowingPunctuation = false;
-                            inObjectTypeLiteral = saveInObjectTypeLiteral;
+
+                    writeSpreadTypeWorker(type, /*atEnd*/true, type.symbol);
+
+                    writer.decreaseIndent();
+                    writePunctuation(writer, SyntaxKind.CloseBraceToken);
+                }
+
+                function writeSpreadTypeWorker(type: SpreadType, atEnd: boolean, container: Symbol): void {
+                    if (type.left.flags & TypeFlags.Spread) {
+                        writeSpreadTypeWorker(type.left as SpreadType, /*atEnd*/false, container);
+                    }
+                    else {
+                        const saveInObjectTypeLiteral = inObjectTypeLiteral;
+                        inObjectTypeLiteral = true;
+                        writeObjectLiteralType(resolveStructuredTypeMembers(type.left));
+                        inObjectTypeLiteral = saveInObjectTypeLiteral;
+                    }
+                    if (type.right.symbol === container) {
+                        const saveInObjectTypeLiteral = inObjectTypeLiteral;
+                        inObjectTypeLiteral = true;
+                        writeObjectLiteralType(resolveStructuredTypeMembers(type.right));
+                        inObjectTypeLiteral = saveInObjectTypeLiteral;
+                    }
+                    else {
+                        writePunctuation(writer, SyntaxKind.DotDotDotToken);
+                        writeType(type.right, TypeFormatFlags.None);
+                        if (atEnd) {
+                            writeSpace(writer);
                         }
                         else {
-                            writePunctuation(writer, SyntaxKind.DotDotDotToken);
-                            writeType(t, TypeFormatFlags.None);
-                            printFollowingPunctuation = true;
+                            writePunctuation(writer, SyntaxKind.SemicolonToken);
+                            writer.writeLine();
                         }
                     }
-                    const resolved = resolveStructuredTypeMembers(type);
-                    writeIndexSignature(resolved.stringIndexInfo, SyntaxKind.StringKeyword);
-                    writeIndexSignature(resolved.numberIndexInfo, SyntaxKind.NumberKeyword);
-                    writer.decreaseIndent();
-                    if (printFollowingPunctuation) {
-                        writeSpace(writer);
-                    }
-                    writePunctuation(writer, SyntaxKind.CloseBraceToken);
                 }
 
                 function writeAnonymousType(type: ObjectType, flags: TypeFormatFlags) {
@@ -3522,6 +3529,9 @@ namespace ts {
             if (symbol.flags & SymbolFlags.Instantiated) {
                 return getTypeOfInstantiatedSymbol(symbol);
             }
+            if (symbol.flags & SymbolFlags.SyntheticProperty && symbol.syntheticKind === SyntheticSymbolKind.Spread) {
+                return getTypeOfSpreadProperty(symbol);
+            }
             if (symbol.flags & (SymbolFlags.Variable | SymbolFlags.Property)) {
                 return getTypeOfVariableOrParameterOrProperty(symbol);
             }
@@ -3540,6 +3550,15 @@ namespace ts {
             return unknownType;
         }
 
+        function getTypeOfSpreadProperty(symbol: Symbol) {
+            const links = getSymbolLinks(symbol);
+            if (!links.type) {
+                links.type = getUnionType([getTypeOfSymbol(links.leftSpread), getTypeOfSymbol(links.rightSpread)]);
+            }
+            return links.type;
+
+        }
+
         function getTargetType(type: ObjectType): Type {
             return type.flags & TypeFlags.Reference ? (<TypeReference>type).target : type;
         }
@@ -4340,21 +4359,6 @@ namespace ts {
             setObjectTypeMembers(type, emptySymbols, callSignatures, constructSignatures, stringIndexInfo, numberIndexInfo);
         }
 
-        function resolveSpreadTypeMembers(type: SpreadType) {
-            // The members and properties collections are empty for spread types. To get all properties of an
-            // spread type use getPropertiesOfType.
-            let stringIndexInfo: IndexInfo = getIndexInfoOfSymbol(type.symbol, IndexKind.String);
-            let numberIndexInfo: IndexInfo = getIndexInfoOfSymbol(type.symbol, IndexKind.Number);
-            for (let i = type.types.length - 1; i > -1; i--) {
-                const t = type.types[i];
-                if (!t.isDeclaredProperty) {
-                    stringIndexInfo = unionIndexInfos(stringIndexInfo, getIndexInfoOfType(t, IndexKind.String));
-                    numberIndexInfo = unionIndexInfos(numberIndexInfo, getIndexInfoOfType(t, IndexKind.Number));
-                }
-            }
-            setObjectTypeMembers(type, emptySymbols, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
-        }
-
         function resolveAnonymousTypeMembers(type: AnonymousType) {
             const symbol = type.symbol;
             if (type.target) {
@@ -4421,9 +4425,6 @@ namespace ts {
                 else if (type.flags & TypeFlags.Intersection) {
                     resolveIntersectionTypeMembers(<IntersectionType>type);
                 }
-                else if (type.flags & TypeFlags.Spread) {
-                    resolveSpreadTypeMembers(<SpreadType>type);
-                }
             }
             return <ResolvedType>type;
         }
@@ -4433,9 +4434,6 @@ namespace ts {
             if (type.flags & TypeFlags.ObjectType) {
                 return resolveStructuredTypeMembers(<ObjectType>type).properties;
             }
-            if (type.flags & TypeFlags.Spread) {
-                return getPropertiesOfType(type);
-            }
             return emptyArray;
         }
 
@@ -4451,11 +4449,10 @@ namespace ts {
             }
         }
 
-        function getPropertiesOfUnionOrIntersectionOrSpreadType(type: TypeOperatorType): Symbol[] {
-            const getProperty = type.flags & TypeFlags.Spread ? getPropertyOfSpreadType : getUnionOrIntersectionProperty;
+        function getPropertiesOfUnionOrIntersectionType(type: TypeOperatorType): Symbol[] {
             for (const current of type.types) {
                 for (const prop of getPropertiesOfType(current)) {
-                    getProperty(type, prop.name);
+                    getUnionOrIntersectionProperty(type, prop.name);
                 }
                 // The properties of a union type are those that are present in all constituent types, so
                 // we only need to check the properties of the first type
@@ -4480,8 +4477,10 @@ namespace ts {
 
         function getPropertiesOfType(type: Type): Symbol[] {
             type = getApparentType(type);
-            return type.flags & (TypeFlags.UnionOrIntersection | TypeFlags.Spread) ? getPropertiesOfUnionOrIntersectionOrSpreadType(<UnionType>type) :
-                getPropertiesOfObjectType(type);
+            if (type.flags & TypeFlags.UnionOrIntersection) {
+                return getPropertiesOfUnionOrIntersectionType(<UnionType>type);
+            }
+            return getPropertiesOfObjectType(type);
         }
 
         /**
@@ -4499,6 +4498,10 @@ namespace ts {
             return type.resolvedApparentType;
         }
 
+        function getApparentTypeOfSpread(type: SpreadType) {
+            return getSpreadType([getApparentType(type.left), getApparentType(type.right)], type.symbol, undefined, undefined);
+        }
+
         /**
          * For a type parameter, return the base constraint of the type parameter. For the string, number,
          * boolean, and symbol primitive types, return the corresponding object types. Otherwise return the
@@ -4507,7 +4510,10 @@ namespace ts {
         function getApparentType(type: Type): Type {
             if (type.flags & TypeFlags.TypeParameter) {
                 type = getApparentTypeOfTypeParameter(<TypeParameter>type);
-          }
+            }
+            if (type.flags & TypeFlags.Spread) {
+                type = getApparentTypeOfSpread(type as SpreadType);
+            }
             if (type.flags & TypeFlags.StringLike) {
                 type = globalStringType;
             }
@@ -4585,6 +4591,7 @@ namespace ts {
                 propTypes.push(type);
             }
             const result = <TransientSymbol>createSymbol(SymbolFlags.Property | SymbolFlags.Transient | SymbolFlags.SyntheticProperty | flags, name);
+            result.syntheticKind === SyntheticSymbolKind.UnionOrIntersection;
             result.containingType = containingType;
             result.hasNonUniformType = hasNonUniformType;
             result.isPartial = isPartial;
@@ -4614,61 +4621,6 @@ namespace ts {
             return property;
         }
 
-        function createSpreadProperty(containingType: SpreadType, name: string): Symbol {
-            const types = containingType.types;
-            return createUnionOrIntersectionOrSpreadPropertySymbol(containingType, name, () => {
-                let props: Symbol[];
-                // Result is readonly if any source is readonly
-                let isReadonly = false;
-                // Result is optional if all sources are optional
-                let commonFlags = SymbolFlags.Optional;
-                for (let i = types.length - 1; i > -1; i--) {
-                    const type = getApparentType(types[i]);
-                    if (type !== unknownType) {
-                        const prop = getPropertyOfType(type, name);
-                        if (prop) {
-                            if (prop.flags & SymbolFlags.Method && !types[i].isDeclaredProperty ||
-                                prop.flags & SymbolFlags.SetAccessor && !(prop.flags & SymbolFlags.GetAccessor)) {
-                                // skip non-object-literal methods and set-only properties and keep looking
-                                continue;
-                            }
-                            if (!props) {
-                                props = [prop];
-                            }
-                            else if (!contains(props, prop)) {
-                                props.unshift(prop);
-                            }
-                            if (isReadonlySymbol(prop)) {
-                                isReadonly = true;
-                            }
-                            if (getDeclarationModifierFlagsFromSymbol(prop) & (ModifierFlags.Private | ModifierFlags.Protected)) {
-                                // return immediately because even if prop is optional, it would make the unioned spread property private
-                                return [undefined, false, false, 0];
-                            }
-                            if (!(prop.flags & SymbolFlags.Optional)) {
-                                // Reset extraFlags to None since we found a non-optional property
-                                commonFlags = SymbolFlags.None;
-                                break;
-                            }
-                        }
-                    }
-                }
-                return [props, isReadonly, /*isPartial*/ false, commonFlags];
-            });
-        }
-
-        function getPropertyOfSpreadType(type: TypeOperatorType, name: string): Symbol {
-            const properties = type.resolvedProperties || (type.resolvedProperties = createMap<Symbol>());
-            let property = properties[name];
-            if (!property) {
-                property = createSpreadProperty(type as SpreadType, name);
-                if (property) {
-                    properties[name] = property;
-                }
-            }
-            return property;
-        }
-
         function getPropertyOfUnionOrIntersectionType(type: TypeOperatorType, name: string): Symbol {
             const property = getUnionOrIntersectionProperty(type, name);
             // We need to filter out partial properties in union types
@@ -4702,9 +4654,6 @@ namespace ts {
             if (type.flags & TypeFlags.UnionOrIntersection) {
                 return getPropertyOfUnionOrIntersectionType(<TypeOperatorType>type, name);
             }
-            if (type.flags & TypeFlags.Spread) {
-                return getPropertyOfSpreadType(<SpreadType>type, name);
-            }
             return undefined;
         }
 
@@ -5775,16 +5724,14 @@ namespace ts {
                 let type: ObjectType;
                 if (isSpread) {
                     let members: Map<Symbol>;
-                    const spreads: SpreadElementType[] = [];
+                    const spreads: Type[] = [];
                     for (const member of (node as TypeLiteralNode).members) {
                         if (member.kind === SyntaxKind.SpreadTypeElement) {
                             if (members) {
-                                const t = createAnonymousType(undefined, members, emptyArray, emptyArray, undefined, undefined) as SpreadElementType;
-                                t.isDeclaredProperty = true;
-                                spreads.push(t);
+                                spreads.push(createAnonymousType(node.symbol, members, emptyArray, emptyArray, undefined, undefined));
                                 members = undefined;
                             }
-                            spreads.push(getTypeFromTypeNode((member as SpreadTypeElement).type) as SpreadElementType);
+                            spreads.push(getTypeFromTypeNode((member as SpreadTypeElement).type));
                         }
                         else if (member.kind !== SyntaxKind.CallSignature &&
                                  member.kind !== SyntaxKind.ConstructSignature &&
@@ -5803,11 +5750,9 @@ namespace ts {
                         }
                     }
                     if (members) {
-                        const t = createAnonymousType(undefined, members, emptyArray, emptyArray, undefined, undefined) as SpreadElementType;
-                        t.isDeclaredProperty = true;
-                        spreads.push(t);
+                        spreads.push(createAnonymousType(node.symbol, members, emptyArray, emptyArray, undefined, undefined));
                     }
-                    return getSpreadType(spreads, node.symbol);
+                    return getSpreadType(spreads, node.symbol, aliasSymbol, aliasTypeArguments);
                 }
                 else {
                     type = createObjectType(TypeFlags.Anonymous, node.symbol);
@@ -5819,13 +5764,94 @@ namespace ts {
             return links.resolvedType;
         }
 
-        function getSpreadType(types: SpreadElementType[], symbol: Symbol, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
+        function getSpreadType(types: Type[], symbol: Symbol, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
+            if (types.length === 0) {
+                return emptyObjectType;
+            }
             const id = getTypeListId(types);
             if (id in spreadTypes) {
                 return spreadTypes[id];
             }
+            const right = types.pop();
+            if (right.flags & TypeFlags.Spread) {
+                // spread is right associative and associativity applies, so transform
+                // (T ... U) ... V to T ... (U ... V)
+                const rspread = right as SpreadType;
+                if (rspread.left !== emptyObjectType) {
+                    types.push(rspread.left);
+                }
+                types.push(rspread.right);
+                return getSpreadType(types, symbol, aliasSymbol, aliasTypeArguments);
+            }
+            const atBeginning = types.length === 0;
+            const left = getSpreadType(types, symbol, aliasSymbol, aliasTypeArguments);
+            if (right.flags & (TypeFlags.Null | TypeFlags.Undefined)) {
+                return left;
+            }
+            if (right.flags & TypeFlags.TypeParameter &&
+                left.flags & TypeFlags.Spread &&
+                (left as SpreadType).right.flags & TypeFlags.TypeParameter &&
+                right.symbol === (left as SpreadType).right.symbol) {
+                // for types like T ... T, just return ... T
+                return left;
+            }
+            if (!(right.flags & (TypeFlags.Union | TypeFlags.Intersection | TypeFlags.TypeParameter | TypeFlags.Spread))
+                && !(left.flags & (TypeFlags.Union | TypeFlags.Intersection | TypeFlags.TypeParameter | TypeFlags.Spread))) {
+                const members = createMap<Symbol | undefined>();
+                const skippedPrivateMembers = createMap<boolean>();
+                let stringIndexInfo = unionIndexInfos(getIndexInfoOfType(left, IndexKind.String), getIndexInfoOfType(right, IndexKind.String));
+                let numberIndexInfo = unionIndexInfos(getIndexInfoOfType(left, IndexKind.Number), getIndexInfoOfType(right, IndexKind.Number));
+                if (atBeginning) {
+                    // only get index info from the entire type once per spread type
+                    stringIndexInfo = unionIndexInfos(stringIndexInfo, getIndexInfoOfSymbol(symbol, IndexKind.String));
+                    numberIndexInfo = unionIndexInfos(numberIndexInfo, getIndexInfoOfSymbol(symbol, IndexKind.Number));
+                }
+                const isFromSpread = right.symbol !== symbol;
+                for (const rightProp of getPropertiesOfType(right)) {
+                    if (getDeclarationModifierFlagsFromSymbol(rightProp) & (ModifierFlags.Private | ModifierFlags.Protected)) {
+                        skippedPrivateMembers[rightProp.name] = true;
+                    }
+                    else if (!(rightProp.flags & SymbolFlags.Method && isFromSpread) &&
+                             !(rightProp.flags & SymbolFlags.SetAccessor && !(rightProp.flags & SymbolFlags.GetAccessor))) {
+                        // skip methods from spreads and accessors with setters but no getters
+                        members[rightProp.name] = rightProp;
+                    }
+                }
+                for (const leftProp of getPropertiesOfType(left)) {
+                    if (leftProp.flags & SymbolFlags.SetAccessor && !(leftProp.flags & SymbolFlags.GetAccessor)
+                       || leftProp.name in skippedPrivateMembers) {
+                        // skip set-only properties (methods have already been skipped by the recursive call to getSpreadType)
+                        continue;
+                    }
+                    if (leftProp.name in members) {
+                        const rightProp = members[leftProp.name];
+                        if (rightProp.flags & SymbolFlags.Optional) {
+                            const declarations: Declaration[] = concatenate(leftProp.declarations, rightProp.declarations);
+                            const flags = SymbolFlags.Property | SymbolFlags.Transient | SymbolFlags.SyntheticProperty | (leftProp.flags & SymbolFlags.Optional);
+                            const result = <TransientSymbol>createSymbol(flags, leftProp.name);
+                            result.syntheticKind = SyntheticSymbolKind.Spread;
+                            result.leftSpread = leftProp;
+                            result.rightSpread = rightProp;
+                            result.declarations = declarations;
+                            if (declarations.length) {
+                                result.valueDeclaration = declarations[0];
+                            }
+                            result.isReadonly = isReadonlySymbol(rightProp) || isReadonlySymbol(leftProp);
+                            members[leftProp.name] = result;
+                        }
+                    }
+                    else {
+                        members[leftProp.name] = leftProp;
+                    }
+                }
+                return createAnonymousType(symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
+            }
+            // one side is a type parameter (TODO: Or union or intersection)
             const spread = spreadTypes[id] = createObjectType(TypeFlags.Spread, symbol) as SpreadType;
-            spread.types = filter(types, t => !(t.flags & (TypeFlags.Null | TypeFlags.Undefined)));
+            Debug.assert(!!(left.flags & (TypeFlags.Spread | TypeFlags.ObjectType)));
+            Debug.assert(!!(right.flags & (TypeFlags.TypeParameter | TypeFlags.ObjectType)));
+            spread.left = left as SpreadType | ResolvedType;
+            spread.right = right as TypeParameter | ResolvedType;
             spread.aliasSymbol = aliasSymbol;
             spread.aliasTypeArguments = aliasTypeArguments;
             return spread;
@@ -6238,7 +6264,8 @@ namespace ts {
                     return getIntersectionType(instantiateList((<IntersectionType>type).types, mapper, instantiateType), type.aliasSymbol, mapper.targetTypes);
                 }
                 if (type.flags & TypeFlags.Spread) {
-                    return getSpreadType(instantiateList((type as SpreadType).types, mapper, instantiateType) as SpreadElementType[], type.symbol, type.aliasSymbol, mapper.targetTypes);
+                    const spread = type as SpreadType;
+                    return getSpreadType([instantiateType(spread.left, mapper), instantiateType(spread.right, mapper)], type.symbol, type.aliasSymbol, mapper.targetTypes);
                 }
             }
             return type;
@@ -6776,38 +6803,15 @@ namespace ts {
                 }
 
                 if (source.flags & TypeFlags.Spread) {
-                    if (target.flags & TypeFlags.TypeParameter) {
-                        let hasTypeParameter = false;
-                        let typeParametersAreEqual = true;
-                        for (const t of (source as SpreadType).types) {
-                            if (t.flags & TypeFlags.TypeParameter) {
-                                hasTypeParameter = true;
-                                if (t !== target) {
-                                    typeParametersAreEqual = false;
-                                    break;
-                                }
-                            }
-                        }
-                        if (hasTypeParameter && typeParametersAreEqual) {
-                            errorInfo = saveErrorInfo;
-                            return Ternary.True;
-                        }
-                    }
-                    else if (target.flags & TypeFlags.Spread) {
-                        const sourceParameters = filter((source as SpreadType).types, t => !!(t.flags & TypeFlags.TypeParameter));
-                        const targetParameters = filter((target as SpreadType).types, t => !!(t.flags & TypeFlags.TypeParameter));
-                        if (sourceParameters.length !== targetParameters.length) {
+                    // you only see this for spreads with type parameters (TODO: and unions/intersections)
+                    if (target.flags & TypeFlags.Spread) {
+                        if (!(spreadTypeRelatedTo(source as SpreadType, target as SpreadType))) {
                             reportRelationError(headMessage, source, target);
                             return Ternary.False;
                         }
-                        for (let i = 0; i < sourceParameters.length; i++) {
-                            if (sourceParameters[i].symbol !== targetParameters[i].symbol) {
-                                reportRelationError(headMessage, source, target);
-                                return Ternary.False;
-                            }
-                        }
                         const reportStructuralErrors = reportErrors && errorInfo === saveErrorInfo;
-                        if (result = objectTypeRelatedTo(source, source, target, reportStructuralErrors)) {
+                        const apparentSource = getApparentType(source);
+                        if (result = objectTypeRelatedTo(apparentSource, source, getApparentType(target), reportStructuralErrors)) {
                             errorInfo = saveErrorInfo;
                             return result;
                         }
@@ -6815,6 +6819,13 @@ namespace ts {
                 }
 
                 if (source.flags & TypeFlags.TypeParameter) {
+                    if (target.flags & TypeFlags.Spread) {
+                        // T is assignable to ...T
+                        if (source.symbol === (target as SpreadType).right.symbol
+                            && (target as SpreadType).left === emptyObjectType) {
+                            return Ternary.True;
+                        }
+                    }
                     let constraint = getConstraintOfTypeParameter(<TypeParameter>source);
 
                     if (!constraint || constraint.flags & TypeFlags.Any) {
@@ -6844,7 +6855,7 @@ namespace ts {
                     // In a check of the form X = A & B, we will have previously checked if A relates to X or B relates
                     // to X. Failing both of those we want to check if the aggregation of A and B's members structurally
                     // relates to X. Thus, we include intersection types on the source side here.
-                    if (apparentSource.flags & (TypeFlags.ObjectType | TypeFlags.Intersection | TypeFlags.Spread) && target.flags & TypeFlags.ObjectType) {
+                    if (apparentSource.flags & (TypeFlags.ObjectType | TypeFlags.Intersection) && target.flags & TypeFlags.ObjectType) {
                         // Report structural errors only if we haven't reported any errors yet
                         const reportStructuralErrors = reportErrors && errorInfo === saveErrorInfo && !(source.flags & TypeFlags.Primitive);
                         if (result = objectTypeRelatedTo(apparentSource, source, target, reportStructuralErrors)) {
@@ -6866,6 +6877,43 @@ namespace ts {
                 return Ternary.False;
             }
 
+            function spreadTypeRelatedTo(source: SpreadType, target: SpreadType): boolean {
+                // (Spread ... Object) | (Spread | Object ... TypeParameter)
+                // in other words, if the right side is Object, then the left side must be a Spread.
+                if (source.right.flags & TypeFlags.ObjectType &&
+                    target.right.flags & TypeFlags.ObjectType) {
+                    return spreadTypeRelatedTo(source.left as SpreadType, target.left as SpreadType);
+                }
+                if (source.right.flags & TypeFlags.ObjectType) {
+                    /// target.right is TypeParameter, skip source.right, but keep looking at target
+                    return spreadTypeRelatedTo(source.left as SpreadType, target);
+                }
+                if (target.right.flags & TypeFlags.ObjectType) {
+                    /// source.right is TypeParameter, skip target.right, but keep looking at source
+                    return spreadTypeRelatedTo(source, target.left as SpreadType);
+                }
+                else {
+                    // both rights are type parameters, so they must be identical
+                    // and both lefts must be the same:
+                    // if one left is object and the other is spread, that means the second has another type parameter. which isn't allowed
+                    if (target.right.symbol !== source.right.symbol) {
+                        return false;
+                    }
+                    if (source.left.flags & TypeFlags.Spread && target.left.flags & TypeFlags.Spread) {
+                        return spreadTypeRelatedTo(source.left as SpreadType, target.left as SpreadType);
+                    }
+                    else if (source.left.flags & TypeFlags.ObjectType && target.left.flags & TypeFlags.ObjectType) {
+                        return true; // let structural compatibility figure it out later
+                    }
+                    else {
+                        // one side is a spread, so it must have more type parameters, which will not be matched by the other side
+                        // return false immediately instead of descending to find this out.
+                        return false;
+                    }
+                }
+
+            }
+
             function isIdenticalTo(source: Type, target: Type): Ternary {
                 let result: Ternary;
                 if (source.flags & TypeFlags.ObjectType && target.flags & TypeFlags.ObjectType) {
@@ -10558,7 +10606,7 @@ namespace ts {
 
             let propertiesTable = createMap<Symbol>();
             let propertiesArray: Symbol[] = [];
-            const spreads: SpreadElementType[] = [];
+            const spreads: Type[] = [];
             const contextualType = getApparentTypeOfContextualType(node);
             const contextualTypeHasPattern = contextualType && contextualType.pattern &&
                 (contextualType.pattern.kind === SyntaxKind.ObjectBindingPattern || contextualType.pattern.kind === SyntaxKind.ObjectLiteralExpression);
@@ -10631,15 +10679,13 @@ namespace ts {
                 }
                 else if (memberDecl.kind === SyntaxKind.SpreadElementExpression) {
                     if (propertiesArray.length > 0) {
-                        const t = createObjectLiteralType() as SpreadElementType;
-                        t.isDeclaredProperty = true;
-                        spreads.push(t);
+                        spreads.push(createObjectLiteralType());
                         propertiesArray = [];
                         propertiesTable = createMap<Symbol>();
                         hasComputedStringProperty = false;
                         hasComputedNumberProperty = false;
                     }
-                    spreads.push(checkExpression((memberDecl as SpreadElementExpression).expression) as SpreadElementType);
+                    spreads.push(checkExpression((memberDecl as SpreadElementExpression).expression));
                     continue;
                 }
                 else {
@@ -10683,17 +10729,16 @@ namespace ts {
 
             if (spreads.length > 0) {
                 if (propertiesArray.length > 0) {
-                    const t = createObjectLiteralType() as SpreadElementType;
-                    t.isDeclaredProperty = true;
-                    spreads.push(t);
+                    spreads.push(createObjectLiteralType());
                 }
                 const propagatedFlags = getPropagatingFlagsOfTypes(spreads, /*excludeKinds*/ TypeFlags.Nullable);
-                const spread = getSpreadType(spreads, node.symbol);
+                const spread = getSpreadType(spreads, node.symbol, undefined, undefined);
                 spread.flags |= propagatedFlags;
                 return spread;
             }
 
             return createObjectLiteralType();
+
             function createObjectLiteralType() {
                 const stringIndexInfo = hasComputedStringProperty ? getObjectLiteralIndexInfo(node, propertiesArray, IndexKind.String) : undefined;
                 const numberIndexInfo = hasComputedNumberProperty ? getObjectLiteralIndexInfo(node, propertiesArray, IndexKind.Number) : undefined;
@@ -10708,7 +10753,6 @@ namespace ts {
                 }
                 return result;
             }
-
        }
 
         function checkJsxSelfClosingElement(node: JsxSelfClosingElement) {
@@ -18943,15 +18987,22 @@ namespace ts {
 
         function getRootSymbols(symbol: Symbol): Symbol[] {
             if (symbol.flags & SymbolFlags.SyntheticProperty) {
-                const symbols: Symbol[] = [];
-                const name = symbol.name;
-                forEach(getSymbolLinks(symbol).containingType.types, t => {
-                    const symbol = getPropertyOfType(t, name);
-                    if (symbol) {
-                        symbols.push(symbol);
-                    }
-                });
-                return symbols;
+                if (symbol.syntheticKind === SyntheticSymbolKind.Spread) {
+                    const name = symbol.name;
+                    const links = getSymbolLinks(symbol);
+                    return [links.leftSpread, links.rightSpread];
+                }
+                else {
+                    const symbols: Symbol[] = [];
+                    const name = symbol.name;
+                    forEach(getSymbolLinks(symbol).containingType.types, t => {
+                        const symbol = getPropertyOfType(t, name);
+                        if (symbol) {
+                            symbols.push(symbol);
+                        }
+                    });
+                    return symbols;
+                }
             }
             else if (symbol.flags & SymbolFlags.Transient) {
                 let target: Symbol;
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 685b94f9d8e06..75aaf03f08b19 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2318,6 +2318,12 @@ namespace ts {
         CannotBeNamed
     }
 
+    /* @internal */
+    export const enum SyntheticSymbolKind {
+        UnionOrIntersection,
+        Spread
+    }
+
     export const enum TypePredicateKind {
         This,
         Identifier
@@ -2442,7 +2448,7 @@ namespace ts {
         Merged                  = 0x02000000,  // Merged symbol (created during program binding)
         Transient               = 0x04000000,  // Transient symbol (created during type check)
         Prototype               = 0x08000000,  // Prototype property (no source representation)
-        SyntheticProperty       = 0x10000000,  // Property in union or intersection type
+        SyntheticProperty       = 0x10000000,  // Property in union, intersection or spread type
         Optional                = 0x20000000,  // Optional property
         ExportStar              = 0x40000000,  // Export * declaration
 
@@ -2517,6 +2523,7 @@ namespace ts {
         /* @internal */ isReferenced?: boolean; // True if the symbol is referenced elsewhere
         /* @internal */ isReplaceableByMethod?: boolean; // Can this Javascript class property be replaced by a method symbol?
         /* @internal */ isAssigned?: boolean;   // True if the symbol is a parameter with assignments
+        /* @internal */ syntheticKind?: SyntheticSymbolKind; // Synthetic symbols are either spread or union/intersection
     }
 
     /* @internal */
@@ -2530,6 +2537,8 @@ namespace ts {
         mapper?: TypeMapper;                // Type mapper for instantiation alias
         referenced?: boolean;               // True if alias symbol has been referenced as a value
         containingType?: TypeOperatorType;  // Containing union or intersection type for synthetic property
+        leftSpread?: Symbol;                // Left source for synthetic spread property
+        rightSpread?: Symbol;               // Right source for synthetic spread property
         hasNonUniformType?: boolean;        // True if constituents have non-uniform types
         isPartial?: boolean;                // True if syntheric property of union type occurs in some but not all constituents
         isDiscriminantProperty?: boolean;   // True if discriminant synthetic property
@@ -2759,13 +2768,9 @@ namespace ts {
     export interface IntersectionType extends TypeOperatorType { }
 
     /* @internal */
-    export interface SpreadType extends TypeOperatorType {
-        types: SpreadElementType[];       // Constituent types
-    }
-
-    /* @internal */
-    export interface SpreadElementType extends ResolvedType {
-        isDeclaredProperty?: boolean;
+    export interface SpreadType extends Type {
+        left: SpreadType | ResolvedType;
+        right: TypeParameter | ResolvedType;
     }
 
     /* @internal */

From 98720755bdb0f6858905d32ed149a2a85cafe7b2 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 7 Oct 2016 08:58:50 -0700
Subject: [PATCH 028/224] Spread type:new assignability+simplification tests

---
 .../conformance/types/spread/objectSpreadGeneric.ts | 13 ++++++-------
 .../types/spread/objectSpreadNegative.ts            |  7 +++----
 .../types/spread/objectSpreadScenarios.ts           |  2 +-
 tests/cases/fourslash/findAllRefsForObjectSpread.ts |  2 +-
 4 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/tests/cases/conformance/types/spread/objectSpreadGeneric.ts b/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
index a6919ce814931..e3bd1ab7bb32a 100644
--- a/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
@@ -1,13 +1,12 @@
 function f<T, U, V>(t: T, u: U, v: V): void {
     let o: { ...T, ...U, ...V };
-    let uu: { ...U, ...U};
-    let u: { ...U };
-    let u0: U;
-    uu = u; // ok, multiple spreads are equivalent to a single one
-    u = uu; // ok, multiple spreads are equivalent to a single one
-    u0 = u; // error, might be missing a ton of stuff
-    u = u0; // ok, type has at least all the properties of the spread
+    let uus: { ...U, ...U};
+    let us: { ...U };
     const same: { ...T, ...U, ...V } = o; // ok
+    uus = us; // ok, multiple spreads are equivalent to a single one
+    us = uus; // ok, multiple spreads are equivalent to a single one
+    us = u;   // ok, type has at least all the properties of the spread
+    u = us;   // error, might be missing a ton of stuff
     const reversed: { ...V, ...U, ...T } = o; // error, reversed
     const reversed2: { ...U, ...T, ...V } = o; // error, U and T are still reversed
     const missingT: { ...U, ...V } = o; // error, missing T
diff --git a/tests/cases/conformance/types/spread/objectSpreadNegative.ts b/tests/cases/conformance/types/spread/objectSpreadNegative.ts
index 4d1cfbe398c32..d492db4c638b9 100644
--- a/tests/cases/conformance/types/spread/objectSpreadNegative.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadNegative.ts
@@ -8,10 +8,8 @@ class PrivateOptionalX {
 class PublicX {
     public x: number;
 }
-let privateOptionalx: PrivateOptionalX;
-let publicx: PublicX;
-let o3 = { ...publicx, ...privateOptionalx };
-let sn: string | number = o3.x; // error, x is private
+let o3: { ...PublicX, ...PrivateOptionalX };
+let sn: number = o3.x; // error, x is private
 let optionalString: { sn?: string };
 let optionalNumber: { sn?: number };
 let allOptional: { sn: string | number } = { ...optionalString, ...optionalNumber };
@@ -46,6 +44,7 @@ let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: numb
 callableConstructableSpread(12); // error, no call signature
 new callableConstructableSpread(12); // error, no construct signature
 
+let publicx: PublicX;
 let callableSpread = { ...publicx, ...(n => n + 1) }; // error, can't spread functions
 
 // { ...U } is not assignable to U
diff --git a/tests/cases/conformance/types/spread/objectSpreadScenarios.ts b/tests/cases/conformance/types/spread/objectSpreadScenarios.ts
index c80cffa44e701..1db930cb71c51 100644
--- a/tests/cases/conformance/types/spread/objectSpreadScenarios.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadScenarios.ts
@@ -3,7 +3,7 @@ interface B1 { b: number };
 function override<U>(initial: U, override: U): { ...U, ...U } {
     return { ...initial, ...override };
 }
-function update<U>(this: { u: U }, override: U): void {
+function update<U>(this: { u: { ...U } }, override: U): void {
     this.u = { ...this.u, ...override };
 }
 function mixin<T, U>(one: T, two: U): { ...T, ...U } {
diff --git a/tests/cases/fourslash/findAllRefsForObjectSpread.ts b/tests/cases/fourslash/findAllRefsForObjectSpread.ts
index fe0a7f9c20195..650324a5d8467 100644
--- a/tests/cases/fourslash/findAllRefsForObjectSpread.ts
+++ b/tests/cases/fourslash/findAllRefsForObjectSpread.ts
@@ -1,6 +1,6 @@
 /// <reference path='fourslash.ts'/>
 
-////interface A1 { [|a|]: number };
+////interface A1 { [|a|]: string };
 ////interface A2 { [|a|]?: number };
 ////let a12: { ...A1, ...A2 };
 ////a12.[|a|];

From df735795e53821575488dcc5d6cf95f1ef96b63a Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 7 Oct 2016 08:59:46 -0700
Subject: [PATCH 029/224] Update baselines

---
 tests/baselines/reference/objectSpread.types  | 72 +++++++++----------
 .../reference/objectSpreadGeneric.errors.txt  | 43 ++++++-----
 .../reference/objectSpreadGeneric.js          | 12 ++++
 .../objectSpreadIndexSignature.types          | 16 ++---
 .../reference/objectSpreadNegative.errors.txt | 67 +++++++++--------
 .../reference/objectSpreadNegative.js         | 21 ++++--
 .../reference/objectSpreadScenarios.js        |  2 +-
 .../reference/objectSpreadScenarios.symbols   |  4 +-
 .../reference/objectSpreadScenarios.types     | 50 ++++++-------
 ...ariableDeclarationInStrictMode1.errors.txt |  2 +-
 10 files changed, 164 insertions(+), 125 deletions(-)

diff --git a/tests/baselines/reference/objectSpread.types b/tests/baselines/reference/objectSpread.types
index 1a053a22670c0..86d04eb4588be 100644
--- a/tests/baselines/reference/objectSpread.types
+++ b/tests/baselines/reference/objectSpread.types
@@ -31,7 +31,7 @@ let addAfter: { a: number, b: string, c: boolean } =
 >c : boolean
 
     { ...o, c: false }
->{ ...o, c: false } : { ...{ a: number; b: string; }; c: false; }
+>{ ...o, c: false } : { c: false; a: number; b: string; }
 >o : any
 >c : boolean
 >false : false
@@ -43,7 +43,7 @@ let addBefore: { a: number, b: string, c: boolean } =
 >c : boolean
 
     { c: false, ...o }
->{ c: false, ...o } : { c: false; ...{ a: number; b: string; } }
+>{ c: false, ...o } : { a: number; b: string; c: false; }
 >c : boolean
 >false : false
 >o : any
@@ -55,7 +55,7 @@ let ignore: { a: number, b: string } =
 >b : string
 
     { b: 'ignored', ...o }
->{ b: 'ignored', ...o } : { b: string; ...{ a: number; b: string; } }
+>{ b: 'ignored', ...o } : { a: number; b: string; }
 >b : string
 >'ignored' : "ignored"
 >o : any
@@ -66,7 +66,7 @@ let override: { a: number, b: string } =
 >b : string
 
     { ...o, b: 'override' }
->{ ...o, b: 'override' } : { ...{ a: number; b: string; }; b: string; }
+>{ ...o, b: 'override' } : { b: string; a: number; }
 >o : any
 >b : string
 >'override' : "override"
@@ -78,8 +78,8 @@ let nested: { a: number, b: boolean, c: string } =
 >c : string
 
     { ...{ a: 3, ...{ b: false, c: 'overriden' } }, c: 'whatever' }
->{ ...{ a: 3, ...{ b: false, c: 'overriden' } }, c: 'whatever' } : { ...{ a: number; ...{ b: boolean; c: string; } }; c: string; }
->{ a: 3, ...{ b: false, c: 'overriden' } } : { a: number; ...{ b: boolean; c: string; } }
+>{ ...{ a: 3, ...{ b: false, c: 'overriden' } }, c: 'whatever' } : { c: string; b: boolean; a: number; }
+>{ a: 3, ...{ b: false, c: 'overriden' } } : { b: boolean; c: string; a: number; }
 >a : number
 >3 : 3
 >{ b: false, c: 'overriden' } : { b: boolean; c: string; }
@@ -97,7 +97,7 @@ let combined: { a: number, b: string, c: boolean } =
 >c : boolean
 
     { ...o, ...o2 }
->{ ...o, ...o2 } : { ...{ a: number; b: string; }; ...{ b: string; c: boolean; } }
+>{ ...o, ...o2 } : { b: string; c: boolean; a: number; }
 >o : any
 >o2 : any
 
@@ -108,7 +108,7 @@ let combinedBefore: { a: number, b: string, c: boolean } =
 >c : boolean
 
     { b: 'ok', ...o, ...o2 }
->{ b: 'ok', ...o, ...o2 } : { b: string; ...{ a: number; b: string; }; ...{ b: string; c: boolean; } }
+>{ b: 'ok', ...o, ...o2 } : { b: string; c: boolean; a: number; }
 >b : string
 >'ok' : "ok"
 >o : any
@@ -121,7 +121,7 @@ let combinedMid: { a: number, b: string, c: boolean } =
 >c : boolean
 
     { ...o, b: 'ok', ...o2 }
->{ ...o, b: 'ok', ...o2 } : { ...{ a: number; b: string; }; b: string; ...{ b: string; c: boolean; } }
+>{ ...o, b: 'ok', ...o2 } : { b: string; c: boolean; a: number; }
 >o : any
 >b : string
 >'ok' : "ok"
@@ -134,7 +134,7 @@ let combinedAfter: { a: number, b: string, c: boolean } =
 >c : boolean
 
     { ...o, ...o2, b: 'ok' }
->{ ...o, ...o2, b: 'ok' } : { ...{ a: number; b: string; }; ...{ b: string; c: boolean; }; b: string; }
+>{ ...o, ...o2, b: 'ok' } : { b: string; c: boolean; a: number; }
 >o : any
 >o2 : any
 >b : string
@@ -148,8 +148,8 @@ let combinedNested: { a: number, b: boolean, c: string, d: string } =
 >d : string
 
     { ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } }
->{ ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } } : { ...{ a: number; ...{ b: boolean; c: string; } }; d: string; ...{ a: number; d: string; } }
->{ a: 4, ...{ b: false, c: 'overriden' } } : { a: number; ...{ b: boolean; c: string; } }
+>{ ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } } : { a: number; d: string; b: boolean; c: string; }
+>{ a: 4, ...{ b: false, c: 'overriden' } } : { b: boolean; c: string; a: number; }
 >a : number
 >4 : 4
 >{ b: false, c: 'overriden' } : { b: boolean; c: string; }
@@ -172,8 +172,8 @@ let combinedNestedChangeType: { a: number, b: boolean, c: number } =
 >c : number
 
     { ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 }
->{ ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 } : { ...{ a: number; ...{ b: boolean; c: string; } }; c: number; }
->{ a: 1, ...{ b: false, c: 'overriden' } } : { a: number; ...{ b: boolean; c: string; } }
+>{ ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 } : { c: number; b: boolean; a: number; }
+>{ a: 1, ...{ b: false, c: 'overriden' } } : { b: boolean; c: string; a: number; }
 >a : number
 >1 : 1
 >{ b: false, c: 'overriden' } : { b: boolean; c: string; }
@@ -192,9 +192,9 @@ let propertyNested: { a: { a: number, b: string } } =
 >b : string
 
     { a: { ... o } }
->{ a: { ... o } } : { a: { ...{ a: number; b: string; } }; }
->a : { ...{ a: number; b: string; } }
->{ ... o } : { ...{ a: number; b: string; } }
+>{ a: { ... o } } : { a: { a: number; b: string; }; }
+>a : { a: number; b: string; }
+>{ ... o } : { a: number; b: string; }
 >o : any
 
 // accessors don't copy the descriptor
@@ -211,7 +211,7 @@ let getter: { a: number, c: number } =
 >c : number
 
     { ...op, c: 7 }
->{ ...op, c: 7 } : { ...{ readonly a: number; }; c: number; }
+>{ ...op, c: 7 } : { c: number; readonly a: number; }
 >op : any
 >c : number
 >7 : 7
@@ -260,7 +260,7 @@ let c: C = new C()
 let spreadC: { p: number } = { ...c }
 >spreadC : { p: number; }
 >p : number
->{ ...c } : { ...C }
+>{ ...c } : { p: number; }
 >c : any
 
 // own methods are enumerable
@@ -268,7 +268,7 @@ let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } }
 >cplus : { p: number; plus(): void; }
 >p : number
 >plus : () => void
->{ ...c, plus() { return this.p + 1; } } : { ...C; plus(): any; }
+>{ ...c, plus() { return this.p + 1; } } : { plus(): any; p: number; }
 >c : any
 >plus : () => any
 >this.p + 1 : any
@@ -290,7 +290,7 @@ let changeTypeAfter: { a: string, b: string } =
 >b : string
 
     { ...o, a: 'wrong type?' }
->{ ...o, a: 'wrong type?' } : { ...{ a: number; b: string; }; a: string; }
+>{ ...o, a: 'wrong type?' } : { a: string; b: string; }
 >o : any
 >a : string
 >'wrong type?' : "wrong type?"
@@ -301,7 +301,7 @@ let changeTypeBefore: { a: number, b: string } =
 >b : string
 
     { a: 'wrong type?', ...o };
->{ a: 'wrong type?', ...o } : { a: string; ...{ a: number; b: string; } }
+>{ a: 'wrong type?', ...o } : { a: number; b: string; }
 >a : string
 >'wrong type?' : "wrong type?"
 >o : any
@@ -312,7 +312,7 @@ let changeTypeBoth: { a: string, b: number } =
 >b : number
 
     { ...o, ...swap };
->{ ...o, ...swap } : { ...{ a: number; b: string; }; ...{ a: string; b: number; } }
+>{ ...o, ...swap } : { a: string; b: number; }
 >o : any
 >swap : any
 
@@ -336,7 +336,7 @@ let optionalNumber: { sn?: number };
 let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
 >optionalUnionStops : { sn: string | number | boolean; }
 >sn : string | number | boolean
->{ ...definiteBoolean, ...definiteString, ...optionalNumber } : { ...{ sn: boolean; }; ...{ sn: string; }; ...{ sn?: number; } }
+>{ ...definiteBoolean, ...definiteString, ...optionalNumber } : { sn: string | number; }
 >definiteBoolean : any
 >definiteString : any
 >optionalNumber : any
@@ -344,7 +344,7 @@ let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean
 let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
 >optionalUnionDuplicates : { sn: string | number; }
 >sn : string | number
->{ ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber } : { ...{ sn: boolean; }; ...{ sn: string; }; ...{ sn?: string; }; ...{ sn?: number; } }
+>{ ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber } : { sn: string | number; }
 >definiteBoolean : any
 >definiteString : any
 >optionalString : any
@@ -353,7 +353,7 @@ let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...
 let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
 >allOptional : { sn?: string | number; }
 >sn : string | number
->{ ...optionalString, ...optionalNumber } : { ...{ sn?: string; }; ...{ sn?: number; } }
+>{ ...optionalString, ...optionalNumber } : { sn?: string | number; }
 >optionalString : any
 >optionalNumber : any
 
@@ -364,7 +364,7 @@ let computedFirst: { a: number, b: string, "before everything": number } =
 >b : string
 
     { ['before everything']: 12, ...o, b: 'yes' }
->{ ['before everything']: 12, ...o, b: 'yes' } : { ['before everything']: number; ...{ a: number; b: string; }; b: string; }
+>{ ['before everything']: 12, ...o, b: 'yes' } : { b: string; a: number; ['before everything']: number; }
 >'before everything' : "before everything"
 >12 : 12
 >o : any
@@ -378,7 +378,7 @@ let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number
 >c : boolean
 
     { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
->{ ...o, ['in the middle']: 13, b: 'maybe?', ...o2 } : { ...{ a: number; b: string; }; ['in the middle']: number; b: string; ...{ b: string; c: boolean; } }
+>{ ...o, ['in the middle']: 13, b: 'maybe?', ...o2 } : { b: string; c: boolean; ['in the middle']: number; a: number; }
 >o : any
 >'in the middle' : "in the middle"
 >13 : 13
@@ -392,7 +392,7 @@ let computedAfter: { a: number, b: string, "at the end": number } =
 >b : string
 
     { ...o, b: 'yeah', ['at the end']: 14 }
->{ ...o, b: 'yeah', ['at the end']: 14 } : { ...{ a: number; b: string; }; b: string; ['at the end']: number; }
+>{ ...o, b: 'yeah', ['at the end']: 14 } : { b: string; ['at the end']: number; a: number; }
 >o : any
 >b : string
 >'yeah' : "yeah"
@@ -408,7 +408,7 @@ let shortCutted: { a: number, b: string } = { ...o, a }
 >shortCutted : { a: number; b: string; }
 >a : number
 >b : string
->{ ...o, a } : { ...{ a: number; b: string; }; a: number; }
+>{ ...o, a } : { a: number; b: string; }
 >o : any
 >a : number
 
@@ -441,7 +441,7 @@ let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
 >d : boolean
 
     f({ a: 1, b: 'yes' }, { c: 'no', d: false })
->f({ a: 1, b: 'yes' }, { c: 'no', d: false }) : { id: string; ...{ a: number; b: string; }; ...{ c: string; d: boolean; } }
+>f({ a: 1, b: 'yes' }, { c: 'no', d: false }) : { c: string; d: boolean; a: number; b: string; id: string; }
 >f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
 >{ a: 1, b: 'yes' } : { a: number; b: string; }
 >a : number
@@ -461,7 +461,7 @@ let overlap: { id: string, a: number, b: string } =
 >b : string
 
     f({ a: 1 }, { a: 2, b: 'extra' })
->f({ a: 1 }, { a: 2, b: 'extra' }) : { id: string; ...{ a: number; }; ...{ a: number; b: string; } }
+>f({ a: 1 }, { a: 2, b: 'extra' }) : { a: number; b: string; id: string; }
 >f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
 >{ a: 1 } : { a: number; }
 >a : number
@@ -478,7 +478,7 @@ let overlapConflict: { id:string, a: string } =
 >a : string
 
     f({ a: 1 }, { a: 'mismatch' })
->f({ a: 1 }, { a: 'mismatch' }) : { id: string; ...{ a: number; }; ...{ a: string; } }
+>f({ a: 1 }, { a: 'mismatch' }) : { a: string; id: string; }
 >f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
 >{ a: 1 } : { a: number; }
 >a : number
@@ -495,7 +495,7 @@ let overwriteId: { id: boolean, a: number, c: number, d: string } =
 >d : string
 
     f({ a: 1, id: true }, { c: 1, d: 'no' })
->f({ a: 1, id: true }, { c: 1, d: 'no' }) : { id: string; ...{ a: number; id: boolean; }; ...{ c: number; d: string; } }
+>f({ a: 1, id: true }, { c: 1, d: 'no' }) : { c: number; d: string; a: number; id: boolean; }
 >f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
 >{ a: 1, id: true } : { a: number; id: true; }
 >a : number
@@ -515,13 +515,13 @@ class D { m() { }; q = 2; }
 >2 : 2
 
 let classesAreWrong: { id: string, ...C, ...D } =
->classesAreWrong : { id: string; ...C; ...D }
+>classesAreWrong : { q: number; p: number; id: string; }
 >id : string
 >C : C
 >D : D
 
     f(new C(), new D())
->f(new C(), new D()) : { id: string; ...C; ...D }
+>f(new C(), new D()) : { q: number; p: number; id: string; }
 >f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
 >new C() : C
 >C : typeof C
diff --git a/tests/baselines/reference/objectSpreadGeneric.errors.txt b/tests/baselines/reference/objectSpreadGeneric.errors.txt
index 16dfc835d2607..6e55040f22391 100644
--- a/tests/baselines/reference/objectSpreadGeneric.errors.txt
+++ b/tests/baselines/reference/objectSpreadGeneric.errors.txt
@@ -1,22 +1,31 @@
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(4,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...V; ...U; ...T }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(5,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...T; ...V }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(6,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...V }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(7,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...V }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(8,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...U }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(13,11): error TS2322: Type '{}' is not assignable to type '{ ...T; ...U }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(26,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; second: string; ...T; third: string; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(34,11): error TS2322: Type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-  Property 'first' is missing in type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(36,11): error TS2322: Type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-  Property 'second' is missing in type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(38,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-  Property 'third' is missing in type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(9,5): error TS2322: Type '{ ...U }' is not assignable to type 'U'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(10,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...V; ...U; ...T }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(11,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...T; ...V }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(12,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...V }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(13,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...V }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(14,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...U }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(19,11): error TS2322: Type '{}' is not assignable to type '{ ...T; ...U }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(32,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; second: string; ...T; third: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(40,11): error TS2322: Type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+  Property 'first' is missing in type '{ third: string; second: string; firrrrrrst: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(42,11): error TS2322: Type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+  Property 'second' is missing in type '{ third: string; ssssssssecond: string; first: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(44,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+  Property 'third' is missing in type '{ thirrrrrrrd: string; second: string; first: string; }'.
 
 
-==== tests/cases/conformance/types/spread/objectSpreadGeneric.ts (10 errors) ====
+==== tests/cases/conformance/types/spread/objectSpreadGeneric.ts (11 errors) ====
     function f<T, U, V>(t: T, u: U, v: V): void {
         let o: { ...T, ...U, ...V };
+        let uus: { ...U, ...U};
+        let us: { ...U };
         const same: { ...T, ...U, ...V } = o; // ok
+        uus = us; // ok, multiple spreads are equivalent to a single one
+        us = uus; // ok, multiple spreads are equivalent to a single one
+        us = u;   // ok, type has at least all the properties of the spread
+        u = us;   // error, might be missing a ton of stuff
+        ~
+!!! error TS2322: Type '{ ...U }' is not assignable to type 'U'.
         const reversed: { ...V, ...U, ...T } = o; // error, reversed
               ~~~~~~~~
 !!! error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...V; ...U; ...T }'.
@@ -64,17 +73,17 @@ tests/cases/conformance/types/spread/objectSpreadGeneric.ts(38,11): error TS2322
         const mismatchFirst: { first: string, ...T, second: string, ...U, third: string } =
               ~~~~~~~~~~~~~
 !!! error TS2322: Type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-!!! error TS2322:   Property 'first' is missing in type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }'.
+!!! error TS2322:   Property 'first' is missing in type '{ third: string; second: string; firrrrrrst: string; }'.
             { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, 'first' not found
         const mismatchSecond: { first: string, ...T, second: string, ...U, third: string } =
               ~~~~~~~~~~~~~~
 !!! error TS2322: Type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-!!! error TS2322:   Property 'second' is missing in type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }'.
+!!! error TS2322:   Property 'second' is missing in type '{ third: string; ssssssssecond: string; first: string; }'.
             { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, 'second' not found
         const mismatchLast: { first: string, ...T, second: string, ...U, third: string } =
               ~~~~~~~~~~~~
 !!! error TS2322: Type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-!!! error TS2322:   Property 'third' is missing in type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }'.
+!!! error TS2322:   Property 'third' is missing in type '{ thirrrrrrrd: string; second: string; first: string; }'.
             { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, 'third' not found
     }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadGeneric.js b/tests/baselines/reference/objectSpreadGeneric.js
index 593ab73f98fac..9414b9ef76e86 100644
--- a/tests/baselines/reference/objectSpreadGeneric.js
+++ b/tests/baselines/reference/objectSpreadGeneric.js
@@ -1,7 +1,13 @@
 //// [objectSpreadGeneric.ts]
 function f<T, U, V>(t: T, u: U, v: V): void {
     let o: { ...T, ...U, ...V };
+    let uus: { ...U, ...U};
+    let us: { ...U };
     const same: { ...T, ...U, ...V } = o; // ok
+    uus = us; // ok, multiple spreads are equivalent to a single one
+    us = uus; // ok, multiple spreads are equivalent to a single one
+    us = u;   // ok, type has at least all the properties of the spread
+    u = us;   // error, might be missing a ton of stuff
     const reversed: { ...V, ...U, ...T } = o; // error, reversed
     const reversed2: { ...U, ...T, ...V } = o; // error, U and T are still reversed
     const missingT: { ...U, ...V } = o; // error, missing T
@@ -52,7 +58,13 @@ var __assign = (this && this.__assign) || Object.assign || function(t) {
 };
 function f(t, u, v) {
     var o;
+    var uus;
+    var us;
     var same = o; // ok
+    uus = us; // ok, multiple spreads are equivalent to a single one
+    us = uus; // ok, multiple spreads are equivalent to a single one
+    us = u; // ok, type has at least all the properties of the spread
+    u = us; // error, might be missing a ton of stuff
     var reversed = o; // error, reversed
     var reversed2 = o; // error, U and T are still reversed
     var missingT = o; // error, missing T
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.types b/tests/baselines/reference/objectSpreadIndexSignature.types
index 9a31b0c44512b..6e9ba881db1fb 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.types
+++ b/tests/baselines/reference/objectSpreadIndexSignature.types
@@ -9,7 +9,7 @@ class C {
 >c : boolean
 }
 let c: { ...C, b: string, c?: string, [n: number]: string };
->c : { ...C; b: string; c?: string; [n: number]: string; }
+>c : { [n: number]: string; b: string; c: string | boolean; a: number; }
 >C : C
 >b : string
 >c : string
@@ -18,13 +18,13 @@ let c: { ...C, b: string, c?: string, [n: number]: string };
 let n: number = c.a;
 >n : number
 >c.a : number
->c : { ...C; b: string; c?: string; [n: number]: string; }
+>c : { [n: number]: string; b: string; c: string | boolean; a: number; }
 >a : number
 
 let s: string = c[12];
 >s : string
 >c[12] : string
->c : { ...C; b: string; c?: string; [n: number]: string; }
+>c : { [n: number]: string; b: string; c: string | boolean; a: number; }
 >12 : 12
 
 interface Indexed {
@@ -37,7 +37,7 @@ interface Indexed {
 >a : number
 }
 let i: { ...Indexed, b: number };
->i : { ...Indexed; b: number; [n: string]: number; }
+>i : { [n: string]: number; b: number; a: number; }
 >Indexed : Indexed
 >b : number
 
@@ -45,14 +45,14 @@ n = i[101];
 >n = i[101] : number
 >n : number
 >i[101] : number
->i : { ...Indexed; b: number; [n: string]: number; }
+>i : { [n: string]: number; b: number; a: number; }
 >101 : 101
 
 n = i.b;
 >n = i.b : number
 >n : number
 >i.b : number
->i : { ...Indexed; b: number; [n: string]: number; }
+>i : { [n: string]: number; b: number; a: number; }
 >b : number
 
 interface Indexed2 {
@@ -65,7 +65,7 @@ interface Indexed2 {
 >c : boolean
 }
 let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
->ii : { ...Indexed; ...Indexed2; b: boolean; d: number; [x: string]: number | boolean; }
+>ii : { [x: string]: number | boolean; b: boolean; d: number; c: boolean; a: number; }
 >Indexed : Indexed
 >Indexed2 : Indexed2
 >b : boolean
@@ -74,6 +74,6 @@ let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
 let nb: number | boolean = ii[1001];
 >nb : number | boolean
 >ii[1001] : number | boolean
->ii : { ...Indexed; ...Indexed2; b: boolean; d: number; [x: string]: number | boolean; }
+>ii : { [x: string]: number | boolean; b: boolean; d: number; c: boolean; a: number; }
 >1001 : 1001
 
diff --git a/tests/baselines/reference/objectSpreadNegative.errors.txt b/tests/baselines/reference/objectSpreadNegative.errors.txt
index 1ee3acb823c6a..38e564c3b5d4f 100644
--- a/tests/baselines/reference/objectSpreadNegative.errors.txt
+++ b/tests/baselines/reference/objectSpreadNegative.errors.txt
@@ -1,20 +1,23 @@
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(13,30): error TS2339: Property 'x' does not exist on type '{ ...PublicX; ...PrivateOptionalX }'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(16,5): error TS2322: Type '{ ...{ sn?: string; }; ...{ sn?: number; } }' is not assignable to type '{ sn: string | number; }'.
-  Property 'sn' is optional in type '{ ...{ sn?: string; }; ...{ sn?: number; } }' but required in type '{ sn: string | number; }'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(22,5): error TS2322: Type '{ s: string; }' is not assignable to type '{ ...Bool; ...Str }'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(24,1): error TS2322: Type 'Bool' is not assignable to type '{ ...Bool; ...Str }'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(27,15): error TS2697: Spread properties must be identifiers, property accesses, or object literals.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(28,15): error TS2697: Spread properties must be identifiers, property accesses, or object literals.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(31,36): error TS2300: Duplicate identifier 'b'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(31,53): error TS2300: Duplicate identifier 'b'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(36,12): error TS2339: Property 'b' does not exist on type '{ ...{ b: number; } }'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(42,9): error TS2339: Property 'm' does not exist on type '{ ...C }'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(45,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ ...PublicX }' has no compatible call signatures.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(46,1): error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(48,39): error TS2697: Spread properties must be identifiers, property accesses, or object literals.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(11,21): error TS2339: Property 'x' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(14,5): error TS2322: Type '{ sn?: string | number; }' is not assignable to type '{ sn: string | number; }'.
+  Property 'sn' is optional in type '{ sn?: string | number; }' but required in type '{ sn: string | number; }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(20,5): error TS2322: Type '{ s: string; }' is not assignable to type '{ s: string; b: boolean; }'.
+  Property 'b' is missing in type '{ s: string; }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(22,1): error TS2322: Type 'Bool' is not assignable to type '{ s: string; b: boolean; }'.
+  Property 's' is missing in type 'Bool'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(25,15): error TS2697: Spread properties must be identifiers, property accesses, or object literals.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(26,15): error TS2697: Spread properties must be identifiers, property accesses, or object literals.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(29,36): error TS2300: Duplicate identifier 'b'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(29,53): error TS2300: Duplicate identifier 'b'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(34,12): error TS2339: Property 'b' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(40,9): error TS2339: Property 'm' does not exist on type '{ p: number; }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(43,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ x: number; }' has no compatible call signatures.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(44,1): error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(47,39): error TS2697: Spread properties must be identifiers, property accesses, or object literals.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(51,12): error TS2322: Type '{ ...U }' is not assignable to type 'U'.
 
 
-==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (13 errors) ====
+==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (14 errors) ====
     let o = { a: 1, b: 'no' }
     
     /// private propagates
@@ -24,18 +27,16 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(48,39): error TS269
     class PublicX {
         public x: number;
     }
-    let privateOptionalx: PrivateOptionalX;
-    let publicx: PublicX;
-    let o3 = { ...publicx, ...privateOptionalx };
-    let sn: string | number = o3.x; // error, x is private
-                                 ~
-!!! error TS2339: Property 'x' does not exist on type '{ ...PublicX; ...PrivateOptionalX }'.
+    let o3: { ...PublicX, ...PrivateOptionalX };
+    let sn: number = o3.x; // error, x is private
+                        ~
+!!! error TS2339: Property 'x' does not exist on type '{}'.
     let optionalString: { sn?: string };
     let optionalNumber: { sn?: number };
     let allOptional: { sn: string | number } = { ...optionalString, ...optionalNumber };
         ~~~~~~~~~~~
-!!! error TS2322: Type '{ ...{ sn?: string; }; ...{ sn?: number; } }' is not assignable to type '{ sn: string | number; }'.
-!!! error TS2322:   Property 'sn' is optional in type '{ ...{ sn?: string; }; ...{ sn?: number; } }' but required in type '{ sn: string | number; }'.
+!!! error TS2322: Type '{ sn?: string | number; }' is not assignable to type '{ sn: string | number; }'.
+!!! error TS2322:   Property 'sn' is optional in type '{ sn?: string | number; }' but required in type '{ sn: string | number; }'.
     // error, 'sn' is optional in source, required in target
     
     // assignability as target
@@ -43,11 +44,13 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(48,39): error TS269
     interface Str { s: string };
     let spread: { ...Bool, ...Str } = { s: 'foo' }; // error, missing 'b'
         ~~~~~~
-!!! error TS2322: Type '{ s: string; }' is not assignable to type '{ ...Bool; ...Str }'.
+!!! error TS2322: Type '{ s: string; }' is not assignable to type '{ s: string; b: boolean; }'.
+!!! error TS2322:   Property 'b' is missing in type '{ s: string; }'.
     let b: Bool;
     spread = b; // error, missing 's'
     ~~~~~~
-!!! error TS2322: Type 'Bool' is not assignable to type '{ ...Bool; ...Str }'.
+!!! error TS2322: Type 'Bool' is not assignable to type '{ s: string; b: boolean; }'.
+!!! error TS2322:   Property 's' is missing in type 'Bool'.
     
     // expressions are not allowed
     let o1 = { ...1 + 1 };
@@ -69,7 +72,7 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(48,39): error TS269
     let setterOnly = { ...{ set b (bad: number) { } } };
     setterOnly.b = 12; // error, 'b' does not exist
                ~
-!!! error TS2339: Property 'b' does not exist on type '{ ...{ b: number; } }'.
+!!! error TS2339: Property 'b' does not exist on type '{}'.
     
     // methods are skipped because they aren't enumerable
     class C { p = 1; m() { } }
@@ -77,17 +80,25 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(48,39): error TS269
     let spreadC = { ...c }
     spreadC.m(); // error 'm' is not in '{ ... c }'
             ~
-!!! error TS2339: Property 'm' does not exist on type '{ ...C }'.
+!!! error TS2339: Property 'm' does not exist on type '{ p: number; }'.
     
     let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: number) };
     callableConstructableSpread(12); // error, no call signature
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ ...PublicX }' has no compatible call signatures.
+!!! error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ x: number; }' has no compatible call signatures.
     new callableConstructableSpread(12); // error, no construct signature
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
     
+    let publicx: PublicX;
     let callableSpread = { ...publicx, ...(n => n + 1) }; // error, can't spread functions
                                           ~~~~~~~~~~~~
 !!! error TS2697: Spread properties must be identifiers, property accesses, or object literals.
+    
+    // { ...U } is not assignable to U
+    function override<U>(initial: U, override: U): U {
+        return { ...initial, ...override };
+               ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2322: Type '{ ...U }' is not assignable to type 'U'.
+    }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadNegative.js b/tests/baselines/reference/objectSpreadNegative.js
index 685760f944467..6874380599b61 100644
--- a/tests/baselines/reference/objectSpreadNegative.js
+++ b/tests/baselines/reference/objectSpreadNegative.js
@@ -8,10 +8,8 @@ class PrivateOptionalX {
 class PublicX {
     public x: number;
 }
-let privateOptionalx: PrivateOptionalX;
-let publicx: PublicX;
-let o3 = { ...publicx, ...privateOptionalx };
-let sn: string | number = o3.x; // error, x is private
+let o3: { ...PublicX, ...PrivateOptionalX };
+let sn: number = o3.x; // error, x is private
 let optionalString: { sn?: string };
 let optionalNumber: { sn?: number };
 let allOptional: { sn: string | number } = { ...optionalString, ...optionalNumber };
@@ -46,7 +44,13 @@ let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: numb
 callableConstructableSpread(12); // error, no call signature
 new callableConstructableSpread(12); // error, no construct signature
 
+let publicx: PublicX;
 let callableSpread = { ...publicx, ...(n => n + 1) }; // error, can't spread functions
+
+// { ...U } is not assignable to U
+function override<U>(initial: U, override: U): U {
+    return { ...initial, ...override };
+}
 
 
 //// [objectSpreadNegative.js]
@@ -70,9 +74,7 @@ var PublicX = (function () {
     }
     return PublicX;
 }());
-var privateOptionalx;
-var publicx;
-var o3 = __assign({}, publicx, privateOptionalx);
+var o3;
 var sn = o3.x; // error, x is private
 var optionalString;
 var optionalNumber;
@@ -105,4 +107,9 @@ spreadC.m(); // error 'm' is not in '{ ... c }'
 var callableConstructableSpread;
 callableConstructableSpread(12); // error, no call signature
 new callableConstructableSpread(12); // error, no construct signature
+var publicx;
 var callableSpread = __assign({}, publicx, (function (n) { return n + 1; })); // error, can't spread functions
+// { ...U } is not assignable to U
+function override(initial, override) {
+    return __assign({}, initial, override);
+}
diff --git a/tests/baselines/reference/objectSpreadScenarios.js b/tests/baselines/reference/objectSpreadScenarios.js
index 64739a2b298b0..96ac98d2d3593 100644
--- a/tests/baselines/reference/objectSpreadScenarios.js
+++ b/tests/baselines/reference/objectSpreadScenarios.js
@@ -4,7 +4,7 @@ interface B1 { b: number };
 function override<U>(initial: U, override: U): { ...U, ...U } {
     return { ...initial, ...override };
 }
-function update<U>(this: { u: U }, override: U): void {
+function update<U>(this: { u: { ...U } }, override: U): void {
     this.u = { ...this.u, ...override };
 }
 function mixin<T, U>(one: T, two: U): { ...T, ...U } {
diff --git a/tests/baselines/reference/objectSpreadScenarios.symbols b/tests/baselines/reference/objectSpreadScenarios.symbols
index 784e340a10ce2..cf1e1833ac968 100644
--- a/tests/baselines/reference/objectSpreadScenarios.symbols
+++ b/tests/baselines/reference/objectSpreadScenarios.symbols
@@ -19,13 +19,13 @@ function override<U>(initial: U, override: U): { ...U, ...U } {
 
     return { ...initial, ...override };
 }
-function update<U>(this: { u: U }, override: U): void {
+function update<U>(this: { u: { ...U } }, override: U): void {
 >update : Symbol(update, Decl(objectSpreadScenarios.ts, 4, 1))
 >U : Symbol(U, Decl(objectSpreadScenarios.ts, 5, 16))
 >this : Symbol(this, Decl(objectSpreadScenarios.ts, 5, 19))
 >u : Symbol(u, Decl(objectSpreadScenarios.ts, 5, 26))
 >U : Symbol(U, Decl(objectSpreadScenarios.ts, 5, 16))
->override : Symbol(override, Decl(objectSpreadScenarios.ts, 5, 34))
+>override : Symbol(override, Decl(objectSpreadScenarios.ts, 5, 41))
 >U : Symbol(U, Decl(objectSpreadScenarios.ts, 5, 16))
 
     this.u = { ...this.u, ...override };
diff --git a/tests/baselines/reference/objectSpreadScenarios.types b/tests/baselines/reference/objectSpreadScenarios.types
index 5330029afe127..2d1aa47bd50a8 100644
--- a/tests/baselines/reference/objectSpreadScenarios.types
+++ b/tests/baselines/reference/objectSpreadScenarios.types
@@ -8,7 +8,7 @@ interface B1 { b: number };
 >b : number
 
 function override<U>(initial: U, override: U): { ...U, ...U } {
->override : <U>(initial: U, override: U) => { ...U; ...U }
+>override : <U>(initial: U, override: U) => { ...U }
 >U : U
 >initial : U
 >U : U
@@ -18,28 +18,28 @@ function override<U>(initial: U, override: U): { ...U, ...U } {
 >U : U
 
     return { ...initial, ...override };
->{ ...initial, ...override } : { ...U; ...U }
+>{ ...initial, ...override } : { ...U }
 >initial : any
 >override : any
 }
-function update<U>(this: { u: U }, override: U): void {
->update : <U>(this: { u: U; }, override: U) => void
+function update<U>(this: { u: { ...U } }, override: U): void {
+>update : <U>(this: { u: { ...U }; }, override: U) => void
 >U : U
->this : { u: U; }
->u : U
+>this : { u: { ...U }; }
+>u : { ...U }
 >U : U
 >override : U
 >U : U
 
     this.u = { ...this.u, ...override };
->this.u = { ...this.u, ...override } : { ...U; ...U }
->this.u : U
->this : { u: U; }
->u : U
->{ ...this.u, ...override } : { ...U; ...U }
->this.u : U
->this : { u: U; }
->u : U
+>this.u = { ...this.u, ...override } : { ...U }
+>this.u : { ...U }
+>this : { u: { ...U }; }
+>u : { ...U }
+>{ ...this.u, ...override } : { ...U }
+>this.u : { ...U }
+>this : { u: { ...U }; }
+>u : { ...U }
 >override : any
 }
 function mixin<T, U>(one: T, two: U): { ...T, ...U } {
@@ -73,34 +73,34 @@ let b1: B1 = { b: 101 };
 >101 : 101
 
 a1 = override(a1, { a: false });
->a1 = override(a1, { a: false }) : { ...A1; ...A1 }
+>a1 = override(a1, { a: false }) : { a: boolean; }
 >a1 : A1
->override(a1, { a: false }) : { ...A1; ...A1 }
->override : <U>(initial: U, override: U) => { ...U; ...U }
+>override(a1, { a: false }) : { a: boolean; }
+>override : <U>(initial: U, override: U) => { ...U }
 >a1 : A1
 >{ a: false } : { a: false; }
 >a : boolean
 >false : false
 
 let host = { u: a1, update };
->host : { u: A1; update: <U>(this: { u: U; }, override: U) => void; }
->{ u: a1, update } : { u: A1; update: <U>(this: { u: U; }, override: U) => void; }
+>host : { u: A1; update: <U>(this: { u: { ...U }; }, override: U) => void; }
+>{ u: a1, update } : { u: A1; update: <U>(this: { u: { ...U }; }, override: U) => void; }
 >u : A1
 >a1 : A1
->update : <U>(this: { u: U; }, override: U) => void
+>update : <U>(this: { u: { ...U }; }, override: U) => void
 
 host.update({ a: false });
 >host.update({ a: false }) : void
->host.update : <U>(this: { u: U; }, override: U) => void
->host : { u: A1; update: <U>(this: { u: U; }, override: U) => void; }
->update : <U>(this: { u: U; }, override: U) => void
+>host.update : <U>(this: { u: { ...U }; }, override: U) => void
+>host : { u: A1; update: <U>(this: { u: { ...U }; }, override: U) => void; }
+>update : <U>(this: { u: { ...U }; }, override: U) => void
 >{ a: false } : { a: false; }
 >a : boolean
 >false : false
 
 let mixed = mixin(a1, b1);
->mixed : { ...A1; ...B1 }
->mixin(a1, b1) : { ...A1; ...B1 }
+>mixed : { b: number; a: boolean; }
+>mixin(a1, b1) : { b: number; a: boolean; }
 >mixin : <T, U>(one: T, two: U) => { ...T; ...U }
 >a1 : A1
 >b1 : B1
diff --git a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
index 9dd9a8d41a1bf..46782aaa1d69d 100644
--- a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
+++ b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
@@ -1,4 +1,4 @@
-lib.d.ts(28,18): error TS2300: Duplicate identifier 'eval'.
+lib.d.ts(32,18): error TS2300: Duplicate identifier 'eval'.
 tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS1100: Invalid use of 'eval' in strict mode.
 tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS2300: Duplicate identifier 'eval'.
 

From 4eedfea81f4603d307829268ea934b7ccf725a3e Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 10 Oct 2016 10:05:31 -0700
Subject: [PATCH 030/224] Support unions/intersections in spread types

1. Lift unions and intersections above spread types when creating them
in getSpreadType.
2. Cleanup now-unneeded changes to existing union/intersection code.
3. Cleanup some incorrect errors I added earlier.
---
 src/compiler/checker.ts              | 263 +++++++++++++--------------
 src/compiler/diagnosticMessages.json |  10 +-
 src/compiler/types.ts                |  12 +-
 src/services/findAllReferences.ts    |   6 +-
 4 files changed, 134 insertions(+), 157 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 0e7266b223ccd..9d8ea29a3819b 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2197,7 +2197,7 @@ namespace ts {
                         writeSymbolTypeReference(type.aliasSymbol, typeArguments, 0, typeArguments ? typeArguments.length : 0, nextFlags);
                     }
                     else if (type.flags & TypeFlags.UnionOrIntersection) {
-                        writeUnionOrIntersectionType(<TypeOperatorType>type, nextFlags);
+                        writeUnionOrIntersectionType(<UnionOrIntersectionType>type, nextFlags);
                     }
                     else if (type.flags & TypeFlags.Spread) {
                         writeSpreadType(<SpreadType>type, nextFlags);
@@ -2291,7 +2291,7 @@ namespace ts {
                     }
                 }
 
-                function writeUnionOrIntersectionType(type: TypeOperatorType, flags: TypeFormatFlags) {
+                function writeUnionOrIntersectionType(type: UnionOrIntersectionType, flags: TypeFormatFlags) {
                     if (flags & TypeFormatFlags.InElementType) {
                         writePunctuation(writer, SyntaxKind.OpenParenToken);
                     }
@@ -4449,7 +4449,7 @@ namespace ts {
             }
         }
 
-        function getPropertiesOfUnionOrIntersectionType(type: TypeOperatorType): Symbol[] {
+        function getPropertiesOfUnionOrIntersectionType(type: UnionOrIntersectionType): Symbol[] {
             for (const current of type.types) {
                 for (const prop of getPropertiesOfType(current)) {
                     getUnionOrIntersectionProperty(type, prop.name);
@@ -4499,7 +4499,7 @@ namespace ts {
         }
 
         function getApparentTypeOfSpread(type: SpreadType) {
-            return getSpreadType([getApparentType(type.left), getApparentType(type.right)], type.symbol, undefined, undefined);
+            return getSpreadType([getApparentType(type.left), getApparentType(type.right)], type.symbol);
         }
 
         /**
@@ -4529,44 +4529,35 @@ namespace ts {
             return type;
         }
 
-        function createUnionOrIntersectionProperty(containingType: TypeOperatorType, name: string): Symbol {
+        function createUnionOrIntersectionProperty(containingType: UnionOrIntersectionType, name: string) {
             const types = containingType.types;
-            return createUnionOrIntersectionOrSpreadPropertySymbol(containingType, name, () => {
-                let props: Symbol[];
-                // Flags we want to propagate to the result if they exist in all source symbols
-                let commonFlags = (containingType.flags & TypeFlags.Intersection) ? SymbolFlags.Optional : SymbolFlags.None;
-                let isReadonly = false;
-                let isPartial = false;
-                for (const current of types) {
-                    const type = getApparentType(current);
-                    if (type !== unknownType) {
-                        const prop = getPropertyOfType(type, name);
-                        if (prop && !(getDeclarationModifierFlagsFromSymbol(prop) & (ModifierFlags.Private | ModifierFlags.Protected))) {
-                            commonFlags &= prop.flags;
-                            if (!props) {
-                                props = [prop];
-                            }
-                            else if (!contains(props, prop)) {
-                                props.push(prop);
-                            }
-                            if (isReadonlySymbol(prop)) {
-                                isReadonly = true;
-                            }
-
+            let props: Symbol[];
+            // Flags we want to propagate to the result if they exist in all source symbols
+            let commonFlags = (containingType.flags & TypeFlags.Intersection) ? SymbolFlags.Optional : SymbolFlags.None;
+            let isReadonly = false;
+            let isPartial = false;
+            for (const current of types) {
+                const type = getApparentType(current);
+                if (type !== unknownType) {
+                    const prop = getPropertyOfType(type, name);
+                    if (prop && !(getDeclarationModifierFlagsFromSymbol(prop) & (ModifierFlags.Private | ModifierFlags.Protected))) {
+                        commonFlags &= prop.flags;
+                        if (!props) {
+                            props = [prop];
+                        }
+                        else if (!contains(props, prop)) {
+                            props.push(prop);
                         }
-                        else if (containingType.flags & TypeFlags.Union) {
-                            isPartial = true;
+                        if (isReadonlySymbol(prop)) {
+                            isReadonly = true;
                         }
+
+                    }
+                    else if (containingType.flags & TypeFlags.Union) {
+                        isPartial = true;
                     }
                 }
-                return [props, isReadonly, isPartial, commonFlags];
-            });
-        }
-
-        function createUnionOrIntersectionOrSpreadPropertySymbol(containingType: TypeOperatorType,
-                                                                 name: string,
-                                                                 symbolCreator: () => [Symbol[], boolean, boolean, SymbolFlags]) {
-            const [props, isReadonly, isPartial, flags] = symbolCreator();
+            }
             if (!props) {
                 return undefined;
             }
@@ -4590,7 +4581,7 @@ namespace ts {
                 }
                 propTypes.push(type);
             }
-            const result = <TransientSymbol>createSymbol(SymbolFlags.Property | SymbolFlags.Transient | SymbolFlags.SyntheticProperty | flags, name);
+            const result = <TransientSymbol>createSymbol(SymbolFlags.Property | SymbolFlags.Transient | SymbolFlags.SyntheticProperty | commonFlags, name);
             result.syntheticKind === SyntheticSymbolKind.UnionOrIntersection;
             result.containingType = containingType;
             result.hasNonUniformType = hasNonUniformType;
@@ -4609,7 +4600,7 @@ namespace ts {
         // constituents, in which case the isPartial flag is set when the containing type is union type. We need
         // these partial properties when identifying discriminant properties, but otherwise they are filtered out
         // and do not appear to be present in the union type.
-        function getUnionOrIntersectionProperty(type: TypeOperatorType, name: string): Symbol {
+        function getUnionOrIntersectionProperty(type: UnionOrIntersectionType, name: string): Symbol {
             const properties = type.resolvedProperties || (type.resolvedProperties = createMap<Symbol>());
             let property = properties[name];
             if (!property) {
@@ -4621,7 +4612,7 @@ namespace ts {
             return property;
         }
 
-        function getPropertyOfUnionOrIntersectionType(type: TypeOperatorType, name: string): Symbol {
+        function getPropertyOfUnionOrIntersectionType(type: UnionOrIntersectionType, name: string): Symbol {
             const property = getUnionOrIntersectionProperty(type, name);
             // We need to filter out partial properties in union types
             return property && !(property.flags & SymbolFlags.SyntheticProperty && (<TransientSymbol>property).isPartial) ? property : undefined;
@@ -4652,7 +4643,7 @@ namespace ts {
                 return getPropertyOfObjectType(globalObjectType, name);
             }
             if (type.flags & TypeFlags.UnionOrIntersection) {
-                return getPropertyOfUnionOrIntersectionType(<TypeOperatorType>type, name);
+                return getPropertyOfUnionOrIntersectionType(<UnionOrIntersectionType>type, name);
             }
             return undefined;
         }
@@ -5773,6 +5764,9 @@ namespace ts {
                 return spreadTypes[id];
             }
             const right = types.pop();
+            if (right.flags & TypeFlags.Any) {
+                return anyType;
+            }
             if (right.flags & TypeFlags.Spread) {
                 // spread is right associative and associativity applies, so transform
                 // (T ... U) ... V to T ... (U ... V)
@@ -5783,9 +5777,22 @@ namespace ts {
                 types.push(rspread.right);
                 return getSpreadType(types, symbol, aliasSymbol, aliasTypeArguments);
             }
+            if (right.flags & TypeFlags.Intersection) {
+                const spreads = map((right as IntersectionType).types,
+                                    t => getSpreadType(types.slice().concat([t]), symbol, aliasSymbol, aliasTypeArguments));
+                return getIntersectionType(spreads, aliasSymbol, aliasTypeArguments);
+            }
+            if (right.flags & TypeFlags.Union) {
+                // TODO: types is mutable, so this block has to happen before the call to `const left = getSpreadType(...)`
+                // because that call consumes the array. It might be worthwhile to use a simple linked list here instead.
+                // It would avoid the slice+concat call that is needed here for multiple calls to getSpreadType.
+                const spreads = map((right as UnionType).types,
+                                    t => getSpreadType(types.slice().concat([t]), symbol, aliasSymbol, aliasTypeArguments));
+                return getUnionType(spreads, /*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
+            }
             const atBeginning = types.length === 0;
             const left = getSpreadType(types, symbol, aliasSymbol, aliasTypeArguments);
-            if (right.flags & (TypeFlags.Null | TypeFlags.Undefined)) {
+            if (right.flags & TypeFlags.Primitive || left.flags & TypeFlags.Any) {
                 return left;
             }
             if (right.flags & TypeFlags.TypeParameter &&
@@ -5795,9 +5802,18 @@ namespace ts {
                 // for types like T ... T, just return ... T
                 return left;
             }
-            if (!(right.flags & (TypeFlags.Union | TypeFlags.Intersection | TypeFlags.TypeParameter | TypeFlags.Spread))
-                && !(left.flags & (TypeFlags.Union | TypeFlags.Intersection | TypeFlags.TypeParameter | TypeFlags.Spread))) {
-                const members = createMap<Symbol | undefined>();
+            if (left.flags & TypeFlags.Intersection) {
+                const spreads = map((left as IntersectionType).types,
+                                  t => getSpreadType(types.slice().concat([t, right]), symbol, aliasSymbol, aliasTypeArguments));
+                return getIntersectionType(spreads, aliasSymbol, aliasTypeArguments);
+            }
+            if (left.flags & TypeFlags.Union) {
+                const spreads = map((left as UnionType).types,
+                                  t => getSpreadType(types.slice().concat([t, right]), symbol, aliasSymbol, aliasTypeArguments));
+                return getUnionType(spreads, /*subTypeReduction*/ false, aliasSymbol, aliasTypeArguments);
+            }
+            if (right.flags & TypeFlags.ObjectType && left.flags & TypeFlags.ObjectType) {
+                const members = createMap<Symbol>();
                 const skippedPrivateMembers = createMap<boolean>();
                 let stringIndexInfo = unionIndexInfos(getIndexInfoOfType(left, IndexKind.String), getIndexInfoOfType(right, IndexKind.String));
                 let numberIndexInfo = unionIndexInfos(getIndexInfoOfType(left, IndexKind.Number), getIndexInfoOfType(right, IndexKind.Number));
@@ -5820,7 +5836,6 @@ namespace ts {
                 for (const leftProp of getPropertiesOfType(left)) {
                     if (leftProp.flags & SymbolFlags.SetAccessor && !(leftProp.flags & SymbolFlags.GetAccessor)
                        || leftProp.name in skippedPrivateMembers) {
-                        // skip set-only properties (methods have already been skipped by the recursive call to getSpreadType)
                         continue;
                     }
                     if (leftProp.name in members) {
@@ -5836,7 +5851,7 @@ namespace ts {
                             if (declarations.length) {
                                 result.valueDeclaration = declarations[0];
                             }
-                            result.isReadonly = isReadonlySymbol(rightProp) || isReadonlySymbol(leftProp);
+                            result.isReadonly = isReadonlySymbol(leftProp) || isReadonlySymbol(rightProp);
                             members[leftProp.name] = result;
                         }
                     }
@@ -5846,10 +5861,9 @@ namespace ts {
                 }
                 return createAnonymousType(symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
             }
-            // one side is a type parameter (TODO: Or union or intersection)
             const spread = spreadTypes[id] = createObjectType(TypeFlags.Spread, symbol) as SpreadType;
-            Debug.assert(!!(left.flags & (TypeFlags.Spread | TypeFlags.ObjectType)));
-            Debug.assert(!!(right.flags & (TypeFlags.TypeParameter | TypeFlags.ObjectType)));
+            Debug.assert(!!(left.flags & (TypeFlags.Spread | TypeFlags.ObjectType)), "Left flags: " + left.flags.toString(2));
+            Debug.assert(!!(right.flags & (TypeFlags.TypeParameter | TypeFlags.ObjectType)), "Right flags: " + right.flags.toString(2));
             spread.left = left as SpreadType | ResolvedType;
             spread.right = right as TypeParameter | ResolvedType;
             spread.aliasSymbol = aliasSymbol;
@@ -6802,19 +6816,19 @@ namespace ts {
                     }
                 }
 
-                if (source.flags & TypeFlags.Spread) {
-                    // you only see this for spreads with type parameters (TODO: and unions/intersections)
-                    if (target.flags & TypeFlags.Spread) {
-                        if (!(spreadTypeRelatedTo(source as SpreadType, target as SpreadType))) {
+                if (source.flags & TypeFlags.Spread && target.flags & TypeFlags.Spread) {
+                    // you only see this for spreads with type parameters
+                    if (!(spreadTypeRelatedTo(source as SpreadType, target as SpreadType))) {
+                        if (reportErrors) {
                             reportRelationError(headMessage, source, target);
-                            return Ternary.False;
-                        }
-                        const reportStructuralErrors = reportErrors && errorInfo === saveErrorInfo;
-                        const apparentSource = getApparentType(source);
-                        if (result = objectTypeRelatedTo(apparentSource, source, getApparentType(target), reportStructuralErrors)) {
-                            errorInfo = saveErrorInfo;
-                            return result;
                         }
+                        return Ternary.False;
+                    }
+                    const reportStructuralErrors = reportErrors && errorInfo === saveErrorInfo;
+                    const apparentSource = getApparentType(source);
+                    if (result = objectTypeRelatedTo(apparentSource, source, getApparentType(target), reportStructuralErrors)) {
+                        errorInfo = saveErrorInfo;
+                        return result;
                     }
                 }
 
@@ -6878,40 +6892,27 @@ namespace ts {
             }
 
             function spreadTypeRelatedTo(source: SpreadType, target: SpreadType): boolean {
-                // (Spread ... Object) | (Spread | Object ... TypeParameter)
-                // in other words, if the right side is Object, then the left side must be a Spread.
-                if (source.right.flags & TypeFlags.ObjectType &&
-                    target.right.flags & TypeFlags.ObjectType) {
-                    return spreadTypeRelatedTo(source.left as SpreadType, target.left as SpreadType);
-                }
-                if (source.right.flags & TypeFlags.ObjectType) {
-                    /// target.right is TypeParameter, skip source.right, but keep looking at target
-                    return spreadTypeRelatedTo(source.left as SpreadType, target);
-                }
-                if (target.right.flags & TypeFlags.ObjectType) {
-                    /// source.right is TypeParameter, skip target.right, but keep looking at source
-                    return spreadTypeRelatedTo(source, target.left as SpreadType);
+                // If the right side of a spread type is ObjectType, then the left side must be a Spread.
+                // Structural compatibility of the spreads' object types are checked separately in isRelatedTo,
+                // so just skip them for now.
+                if (source.right.flags & TypeFlags.ObjectType || target.right.flags & TypeFlags.ObjectType) {
+                    return spreadTypeRelatedTo(source.right.flags & TypeFlags.ObjectType ? source.left as SpreadType : source,
+                                               target.right.flags & TypeFlags.ObjectType ? target.left as SpreadType : target);
+                }
+                // If both right sides are type parameters, then they must be identical for the spread types to be related.
+                // It also means that the left sides are either spread types or object types.
+
+                // if one left is object and the other is spread, that means the second has another type parameter. which isn't allowed
+                if (target.right.symbol !== source.right.symbol) {
+                    return false;
                 }
-                else {
-                    // both rights are type parameters, so they must be identical
-                    // and both lefts must be the same:
-                    // if one left is object and the other is spread, that means the second has another type parameter. which isn't allowed
-                    if (target.right.symbol !== source.right.symbol) {
-                        return false;
-                    }
-                    if (source.left.flags & TypeFlags.Spread && target.left.flags & TypeFlags.Spread) {
-                        return spreadTypeRelatedTo(source.left as SpreadType, target.left as SpreadType);
-                    }
-                    else if (source.left.flags & TypeFlags.ObjectType && target.left.flags & TypeFlags.ObjectType) {
-                        return true; // let structural compatibility figure it out later
-                    }
-                    else {
-                        // one side is a spread, so it must have more type parameters, which will not be matched by the other side
-                        // return false immediately instead of descending to find this out.
-                        return false;
-                    }
+                if (source.left.flags & TypeFlags.Spread && target.left.flags & TypeFlags.Spread) {
+                    // If the left sides are both spread types, then recursively check them.
+                    return spreadTypeRelatedTo(source.left as SpreadType, target.left as SpreadType);
                 }
-
+                // If the left sides are both object types, then isRelatedTo will check the structural compatibility next.
+                // Otherwise, one side has more type parameters than the other and the spread types are not related.
+                return !!(source.left.flags & TypeFlags.ObjectType && target.left.flags & TypeFlags.ObjectType);
             }
 
             function isIdenticalTo(source: Type, target: Type): Ternary {
@@ -6927,8 +6928,8 @@ namespace ts {
                 }
                 if (source.flags & TypeFlags.Union && target.flags & TypeFlags.Union ||
                     source.flags & TypeFlags.Intersection && target.flags & TypeFlags.Intersection) {
-                    if (result = eachTypeRelatedToSomeType(<TypeOperatorType>source, <TypeOperatorType>target, /*reportErrors*/ false)) {
-                        if (result &= eachTypeRelatedToSomeType(<TypeOperatorType>target, <TypeOperatorType>source, /*reportErrors*/ false)) {
+                    if (result = eachTypeRelatedToSomeType(<UnionOrIntersectionType>source, <UnionOrIntersectionType>target, /*reportErrors*/ false)) {
+                        if (result &= eachTypeRelatedToSomeType(<UnionOrIntersectionType>target, <UnionOrIntersectionType>source, /*reportErrors*/ false)) {
                             return result;
                         }
                     }
@@ -6951,7 +6952,7 @@ namespace ts {
                     }
                 }
                 else if (type.flags & TypeFlags.UnionOrIntersection) {
-                    for (const t of (<TypeOperatorType>type).types) {
+                    for (const t of (<UnionOrIntersectionType>type).types) {
                         if (isKnownProperty(t, name)) {
                             return true;
                         }
@@ -6989,7 +6990,7 @@ namespace ts {
                 return false;
             }
 
-            function eachTypeRelatedToSomeType(source: TypeOperatorType, target: TypeOperatorType, reportErrors: boolean): Ternary {
+            function eachTypeRelatedToSomeType(source: UnionOrIntersectionType, target: UnionOrIntersectionType, reportErrors: boolean): Ternary {
                 let result = Ternary.True;
                 const sourceTypes = source.types;
                 for (const sourceType of sourceTypes) {
@@ -7002,7 +7003,7 @@ namespace ts {
                 return result;
             }
 
-            function typeRelatedToSomeType(source: Type, target: TypeOperatorType, reportErrors: boolean): Ternary {
+            function typeRelatedToSomeType(source: Type, target: UnionOrIntersectionType, reportErrors: boolean): Ternary {
                 const targetTypes = target.types;
                 if (target.flags & TypeFlags.Union && containsType(targetTypes, source)) {
                     return Ternary.True;
@@ -7017,7 +7018,7 @@ namespace ts {
                 return Ternary.False;
             }
 
-            function typeRelatedToEachType(source: Type, target: TypeOperatorType, reportErrors: boolean): Ternary {
+            function typeRelatedToEachType(source: Type, target: UnionOrIntersectionType, reportErrors: boolean): Ternary {
                 let result = Ternary.True;
                 const targetTypes = target.types;
                 for (const targetType of targetTypes) {
@@ -7030,7 +7031,7 @@ namespace ts {
                 return result;
             }
 
-            function someTypeRelatedToType(source: TypeOperatorType, target: Type, reportErrors: boolean): Ternary {
+            function someTypeRelatedToType(source: UnionOrIntersectionType, target: Type, reportErrors: boolean): Ternary {
                 const sourceTypes = source.types;
                 if (source.flags & TypeFlags.Union && containsType(sourceTypes, target)) {
                     return Ternary.True;
@@ -7045,7 +7046,7 @@ namespace ts {
                 return Ternary.False;
             }
 
-            function eachTypeRelatedToType(source: TypeOperatorType, target: Type, reportErrors: boolean): Ternary {
+            function eachTypeRelatedToType(source: UnionOrIntersectionType, target: Type, reportErrors: boolean): Ternary {
                 let result = Ternary.True;
                 const sourceTypes = source.types;
                 for (const sourceType of sourceTypes) {
@@ -7990,10 +7991,10 @@ namespace ts {
             return !!(type.flags & TypeFlags.TypeParameter ||
                 type.flags & TypeFlags.Reference && forEach((<TypeReference>type).typeArguments, couldContainTypeParameters) ||
                 type.flags & TypeFlags.Anonymous && type.symbol && type.symbol.flags & (SymbolFlags.Method | SymbolFlags.TypeLiteral | SymbolFlags.Class) ||
-                type.flags & TypeFlags.UnionOrIntersection && couldUnionOrIntersectionContainTypeParameters(<TypeOperatorType>type));
+                type.flags & TypeFlags.UnionOrIntersection && couldUnionOrIntersectionContainTypeParameters(<UnionOrIntersectionType>type));
         }
 
-        function couldUnionOrIntersectionContainTypeParameters(type: TypeOperatorType): boolean {
+        function couldUnionOrIntersectionContainTypeParameters(type: UnionOrIntersectionType): boolean {
             if (type.couldContainTypeParameters === undefined) {
                 type.couldContainTypeParameters = forEach(type.types, couldContainTypeParameters);
             }
@@ -8001,7 +8002,7 @@ namespace ts {
         }
 
         function isTypeParameterAtTopLevel(type: Type, typeParameter: TypeParameter): boolean {
-            return type === typeParameter || type.flags & TypeFlags.UnionOrIntersection && forEach((<TypeOperatorType>type).types, t => isTypeParameterAtTopLevel(t, typeParameter));
+            return type === typeParameter || type.flags & TypeFlags.UnionOrIntersection && forEach((<UnionOrIntersectionType>type).types, t => isTypeParameterAtTopLevel(t, typeParameter));
         }
 
         function inferTypes(context: InferenceContext, originalSource: Type, originalTarget: Type) {
@@ -8031,7 +8032,7 @@ namespace ts {
                     // Source and target are both unions or both intersections. If source and target
                     // are the same type, just relate each constituent type to itself.
                     if (source === target) {
-                        for (const t of (<TypeOperatorType>source).types) {
+                        for (const t of (<UnionOrIntersectionType>source).types) {
                             inferFromTypes(t, t);
                         }
                         return;
@@ -8043,14 +8044,14 @@ namespace ts {
                     // and string literals because the number and string types are not represented as unions
                     // of all their possible values.
                     let matchingTypes: Type[];
-                    for (const t of (<TypeOperatorType>source).types) {
-                        if (typeIdenticalToSomeType(t, (<TypeOperatorType>target).types)) {
+                    for (const t of (<UnionOrIntersectionType>source).types) {
+                        if (typeIdenticalToSomeType(t, (<UnionOrIntersectionType>target).types)) {
                             (matchingTypes || (matchingTypes = [])).push(t);
                             inferFromTypes(t, t);
                         }
                         else if (t.flags & (TypeFlags.NumberLiteral | TypeFlags.StringLiteral)) {
                             const b = getBaseTypeOfLiteralType(t);
-                            if (typeIdenticalToSomeType(b, (<TypeOperatorType>target).types)) {
+                            if (typeIdenticalToSomeType(b, (<UnionOrIntersectionType>target).types)) {
                                 (matchingTypes || (matchingTypes = [])).push(t, b);
                             }
                         }
@@ -8059,8 +8060,8 @@ namespace ts {
                     // removing the identically matched constituents. For example, when inferring from
                     // 'string | string[]' to 'string | T' we reduce the types to 'string[]' and 'T'.
                     if (matchingTypes) {
-                        source = removeTypesFromUnionOrIntersection(<TypeOperatorType>source, matchingTypes);
-                        target = removeTypesFromUnionOrIntersection(<TypeOperatorType>target, matchingTypes);
+                        source = removeTypesFromUnionOrIntersection(<UnionOrIntersectionType>source, matchingTypes);
+                        target = removeTypesFromUnionOrIntersection(<UnionOrIntersectionType>target, matchingTypes);
                     }
                 }
                 if (target.flags & TypeFlags.TypeParameter) {
@@ -8107,7 +8108,7 @@ namespace ts {
                     }
                 }
                 else if (target.flags & TypeFlags.UnionOrIntersection) {
-                    const targetTypes = (<TypeOperatorType>target).types;
+                    const targetTypes = (<UnionOrIntersectionType>target).types;
                     let typeParameterCount = 0;
                     let typeParameter: TypeParameter;
                     // First infer to each type in union or intersection that isn't a type parameter
@@ -8131,7 +8132,7 @@ namespace ts {
                 }
                 else if (source.flags & TypeFlags.UnionOrIntersection) {
                     // Source is a union or intersection type, infer from each constituent type
-                    const sourceTypes = (<TypeOperatorType>source).types;
+                    const sourceTypes = (<UnionOrIntersectionType>source).types;
                     for (const sourceType of sourceTypes) {
                         inferFromTypes(sourceType, target);
                     }
@@ -8236,7 +8237,7 @@ namespace ts {
          * Return a new union or intersection type computed by removing a given set of types
          * from a given union or intersection type.
          */
-        function removeTypesFromUnionOrIntersection(type: TypeOperatorType, typesToRemove: Type[]) {
+        function removeTypesFromUnionOrIntersection(type: UnionOrIntersectionType, typesToRemove: Type[]) {
             const reducedTypes: Type[] = [];
             for (const t of type.types) {
                 if (!typeIdenticalToSomeType(t, typesToRemove)) {
@@ -8549,7 +8550,7 @@ namespace ts {
                 return getTypeFacts(constraint || emptyObjectType);
             }
             if (flags & TypeFlags.UnionOrIntersection) {
-                return getTypeFactsOfTypes((<TypeOperatorType>type).types);
+                return getTypeFactsOfTypes((<UnionOrIntersectionType>type).types);
             }
             return TypeFacts.All;
         }
@@ -10632,13 +10633,6 @@ namespace ts {
                         type = checkExpressionForMutableLocation((<ShorthandPropertyAssignment>memberDecl).name, contextualMapper);
                     }
 
-                    if (hasProperty(propertiesTable, member.name)) {
-                        const existingPropType = getTypeOfSymbol(propertiesTable[member.name]);
-                        if (!isTypeIdenticalTo(existingPropType, type)) {
-                            error(memberDecl.name, Diagnostics.Cannot_change_type_of_property_0_from_1_to_2, member.name, typeToString(existingPropType), typeToString(type));
-                        }
-                    }
-
                     typeFlags |= type.flags;
                     const prop = <TransientSymbol>createSymbol(SymbolFlags.Property | SymbolFlags.Transient | member.flags, member.name);
                     if (inDestructuringPattern) {
@@ -10992,7 +10986,7 @@ namespace ts {
                 elemType = checkExpression(node.tagName);
             }
             if (elemType.flags & TypeFlags.Union) {
-                const types = (<TypeOperatorType>elemType).types;
+                const types = (<UnionOrIntersectionType>elemType).types;
                 return getUnionType(types.map(type => {
                     return getResolvedJsxType(node, type, elemClassType);
                 }), /*subtypeReduction*/ true);
@@ -13557,7 +13551,7 @@ namespace ts {
                 return true;
             }
             if (type.flags & TypeFlags.UnionOrIntersection) {
-                const types = (<TypeOperatorType>type).types;
+                const types = (<UnionOrIntersectionType>type).types;
                 for (const t of types) {
                     if (maybeTypeOfKind(t, kind)) {
                         return true;
@@ -13575,7 +13569,7 @@ namespace ts {
                 return true;
             }
             if (type.flags & TypeFlags.Union) {
-                const types = (<TypeOperatorType>type).types;
+                const types = (<UnionOrIntersectionType>type).types;
                 for (const t of types) {
                     if (!isTypeOfKind(t, kind)) {
                         return false;
@@ -13584,7 +13578,7 @@ namespace ts {
                 return true;
             }
             if (type.flags & TypeFlags.Intersection) {
-                const types = (<TypeOperatorType>type).types;
+                const types = (<UnionOrIntersectionType>type).types;
                 for (const t of types) {
                     if (isTypeOfKind(t, kind)) {
                         return true;
@@ -14980,9 +14974,11 @@ namespace ts {
             forEach(node.members, checkSourceElement);
             if (produceDiagnostics) {
                 const type = getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node);
-                checkIndexConstraints(type);
-                checkTypeForDuplicateIndexSignatures(node);
-                checkObjectTypeForDuplicateDeclarations(node);
+                if (type.flags & TypeFlags.ObjectType) {
+                    checkIndexConstraints(type);
+                    checkTypeForDuplicateIndexSignatures(node);
+                    checkObjectTypeForDuplicateDeclarations(node);
+                }
             }
         }
 
@@ -20317,17 +20313,6 @@ namespace ts {
 
             for (const prop of node.properties) {
                 if (prop.kind === SyntaxKind.SpreadElementExpression) {
-                    const target = (prop as SpreadElementExpression).expression;
-                    switch (target.kind) {
-                        case SyntaxKind.Identifier:
-                        case SyntaxKind.PropertyAccessExpression:
-                        case SyntaxKind.ObjectLiteralExpression:
-                        case SyntaxKind.NullKeyword:
-                            break;
-                        default:
-                            grammarErrorOnNode(target, Diagnostics.Spread_properties_must_be_identifiers_property_accesses_or_object_literals);
-                    }
-
                     continue;
                 }
                 const name = prop.name;
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 37a335f67cf54..65d67b6bf8392 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1967,17 +1967,9 @@
         "category": "Error",
         "code": 2696
     },
-    "Spread properties must be identifiers, property accesses, or object literals.": {
-        "category": "Error",
-        "code": 2697
-    },
-    "Cannot change type of property '{0}' from '{1}' to '{2}'.": {
-        "category": "Error",
-        "code": 2698
-    },
     "Interface declaration cannot contain a spread property.": {
         "category": "Error",
-        "code": 2699
+        "code": 2697
     },
 
     "Import declaration '{0}' is using private name '{1}'.": {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 75aaf03f08b19..0914f0ba41403 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -1802,7 +1802,7 @@ namespace ts {
 
     export interface JSDocRecordType extends JSDocType {
         kind: SyntaxKind.JSDocRecordType;
-        literal: TypeLiteralNode;

+        literal: TypeLiteralNode;
     }
 
     export interface JSDocTypeReference extends JSDocType {
@@ -2536,7 +2536,7 @@ namespace ts {
         instantiations?: Map<Type>;         // Instantiations of generic type alias (undefined if non-generic)
         mapper?: TypeMapper;                // Type mapper for instantiation alias
         referenced?: boolean;               // True if alias symbol has been referenced as a value
-        containingType?: TypeOperatorType;  // Containing union or intersection type for synthetic property
+        containingType?: UnionOrIntersectionType;  // Containing union or intersection type for synthetic property
         leftSpread?: Symbol;                // Left source for synthetic spread property
         rightSpread?: Symbol;               // Right source for synthetic spread property
         hasNonUniformType?: boolean;        // True if constituents have non-uniform types
@@ -2755,7 +2755,7 @@ namespace ts {
         instantiations: Map<TypeReference>;   // Generic instantiation cache
     }
 
-    export interface TypeOperatorType extends Type {
+    export interface UnionOrIntersectionType extends Type {
         types: Type[];                    // Constituent types
         /* @internal */
         resolvedProperties: SymbolTable;  // Cache of resolved properties
@@ -2763,9 +2763,9 @@ namespace ts {
         couldContainTypeParameters: boolean;
     }
 
-    export interface UnionType extends TypeOperatorType { }
+    export interface UnionType extends UnionOrIntersectionType { }
 
-    export interface IntersectionType extends TypeOperatorType { }
+    export interface IntersectionType extends UnionOrIntersectionType { }
 
     /* @internal */
     export interface SpreadType extends Type {
@@ -2782,7 +2782,7 @@ namespace ts {
 
     /* @internal */
     // Resolved object, spread, union, or intersection type
-    export interface ResolvedType extends ObjectType, TypeOperatorType {
+    export interface ResolvedType extends ObjectType, UnionOrIntersectionType {
         members: SymbolTable;              // Properties by name
         properties: Symbol[];              // Properties
         callSignatures: Signature[];       // Call signatures of type
diff --git a/src/services/findAllReferences.ts b/src/services/findAllReferences.ts
index 8766937c00851..dcda3e40b1a67 100644
--- a/src/services/findAllReferences.ts
+++ b/src/services/findAllReferences.ts
@@ -458,7 +458,7 @@ namespace ts.FindAllReferences {
                                 return [localParentType.symbol];
                             }
                             else if (localParentType.flags & TypeFlags.UnionOrIntersection) {
-                                return getSymbolsForClassAndInterfaceComponents(<TypeOperatorType>localParentType);
+                                return getSymbolsForClassAndInterfaceComponents(<UnionOrIntersectionType>localParentType);
                             }
                         }
                     }
@@ -630,13 +630,13 @@ namespace ts.FindAllReferences {
             }
         }
 
-        function getSymbolsForClassAndInterfaceComponents(type: TypeOperatorType, result: Symbol[] = []): Symbol[] {
+        function getSymbolsForClassAndInterfaceComponents(type: UnionOrIntersectionType, result: Symbol[] = []): Symbol[] {
             for (const componentType of type.types) {
                 if (componentType.symbol && componentType.symbol.getFlags() & (SymbolFlags.Class | SymbolFlags.Interface)) {
                     result.push(componentType.symbol);
                 }
                 if (componentType.getFlags() & TypeFlags.UnionOrIntersection) {
-                    getSymbolsForClassAndInterfaceComponents(<TypeOperatorType>componentType, result);
+                    getSymbolsForClassAndInterfaceComponents(<UnionOrIntersectionType>componentType, result);
                 }
             }
             return result;

From 0dd1f0c00f641b98de531c165d884cfe2728927a Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 10 Oct 2016 10:07:41 -0700
Subject: [PATCH 031/224] Add tests and update baselines.

1. Union/intersection tests.
2. Primitive tests.
3. Update baselines after removing errors.
---
 .../duplicateObjectLiteralProperty.errors.txt |   8 +-
 .../reference/interfaceSpread.errors.txt      |   4 +-
 .../lastPropertyInLiteralWins.errors.txt      |   8 +-
 .../reference/memberOverride.errors.txt       |   5 +-
 .../reference/objectLiteralErrors.errors.txt  |   5 +-
 ...tiesErrorFromNotUsingIdentifier.errors.txt |   8 +-
 tests/baselines/reference/objectSpread.js     |  22 +-
 .../baselines/reference/objectSpread.symbols  | 258 +++++++++---------
 tests/baselines/reference/objectSpread.types  |  43 +--
 .../reference/objectSpreadIntersection.js     |  79 ++++++
 .../objectSpreadIntersection.symbols          | 219 +++++++++++++++
 .../reference/objectSpreadIntersection.types  | 236 ++++++++++++++++
 .../reference/objectSpreadNegative.errors.txt |  76 ++++--
 .../reference/objectSpreadNegative.js         |  56 ++--
 .../baselines/reference/objectSpreadUnion.js  |  52 ++++
 .../reference/objectSpreadUnion.symbols       | 122 +++++++++
 .../reference/objectSpreadUnion.types         | 131 +++++++++
 .../conformance/types/spread/objectSpread.ts  |  12 +-
 .../types/spread/objectSpreadIntersection.ts  |  36 +++
 .../types/spread/objectSpreadNegative.ts      |  30 +-
 .../types/spread/objectSpreadUnion.ts         |  23 ++
 21 files changed, 1194 insertions(+), 239 deletions(-)
 create mode 100644 tests/baselines/reference/objectSpreadIntersection.js
 create mode 100644 tests/baselines/reference/objectSpreadIntersection.symbols
 create mode 100644 tests/baselines/reference/objectSpreadIntersection.types
 create mode 100644 tests/baselines/reference/objectSpreadUnion.js
 create mode 100644 tests/baselines/reference/objectSpreadUnion.symbols
 create mode 100644 tests/baselines/reference/objectSpreadUnion.types
 create mode 100644 tests/cases/conformance/types/spread/objectSpreadIntersection.ts
 create mode 100644 tests/cases/conformance/types/spread/objectSpreadUnion.ts

diff --git a/tests/baselines/reference/duplicateObjectLiteralProperty.errors.txt b/tests/baselines/reference/duplicateObjectLiteralProperty.errors.txt
index 926a707122293..abc56a6f8fce7 100644
--- a/tests/baselines/reference/duplicateObjectLiteralProperty.errors.txt
+++ b/tests/baselines/reference/duplicateObjectLiteralProperty.errors.txt
@@ -1,8 +1,6 @@
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(4,5): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(5,5): error TS2300: Duplicate identifier '\u0061'.
-tests/cases/compiler/duplicateObjectLiteralProperty.ts(5,5): error TS2698: Cannot change type of property 'a' from 'number' to 'string'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(6,5): error TS2300: Duplicate identifier 'a'.
-tests/cases/compiler/duplicateObjectLiteralProperty.ts(6,5): error TS2698: Cannot change type of property 'a' from 'string' to '{ c: number; }'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(8,9): error TS2300: Duplicate identifier '"c"'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(14,9): error TS2300: Duplicate identifier 'a'.
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(15,9): error TS2300: Duplicate identifier 'a'.
@@ -10,7 +8,7 @@ tests/cases/compiler/duplicateObjectLiteralProperty.ts(16,9): error TS1118: An o
 tests/cases/compiler/duplicateObjectLiteralProperty.ts(16,9): error TS2300: Duplicate identifier 'a'.
 
 
-==== tests/cases/compiler/duplicateObjectLiteralProperty.ts (10 errors) ====
+==== tests/cases/compiler/duplicateObjectLiteralProperty.ts (8 errors) ====
     var x = {
         a: 1,
         b: true, // OK
@@ -20,13 +18,9 @@ tests/cases/compiler/duplicateObjectLiteralProperty.ts(16,9): error TS2300: Dupl
         \u0061: "ss", // Duplicate
         ~~~~~~
 !!! error TS2300: Duplicate identifier '\u0061'.
-        ~~~~~~
-!!! error TS2698: Cannot change type of property 'a' from 'number' to 'string'.
         a: {
         ~
 !!! error TS2300: Duplicate identifier 'a'.
-        ~
-!!! error TS2698: Cannot change type of property 'a' from 'string' to '{ c: number; }'.
             c: 1,
             "c": 56, // Duplicate
             ~~~
diff --git a/tests/baselines/reference/interfaceSpread.errors.txt b/tests/baselines/reference/interfaceSpread.errors.txt
index 2b27c972cc895..d8556de9f9379 100644
--- a/tests/baselines/reference/interfaceSpread.errors.txt
+++ b/tests/baselines/reference/interfaceSpread.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/types/spread/interfaceSpread.ts(2,5): error TS2699: Interface declaration cannot contain a spread property.
+tests/cases/conformance/types/spread/interfaceSpread.ts(2,5): error TS2697: Interface declaration cannot contain a spread property.
 tests/cases/conformance/types/spread/interfaceSpread.ts(7,10): error TS2339: Property 'jam' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
 tests/cases/conformance/types/spread/interfaceSpread.ts(8,10): error TS2339: Property 'peanutButter' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
 
@@ -7,7 +7,7 @@ tests/cases/conformance/types/spread/interfaceSpread.ts(8,10): error TS2339: Pro
     interface Congealed<T, U> {
         ...T
         ~~~~
-!!! error TS2699: Interface declaration cannot contain a spread property.
+!!! error TS2697: Interface declaration cannot contain a spread property.
         ...U
     }
     
diff --git a/tests/baselines/reference/lastPropertyInLiteralWins.errors.txt b/tests/baselines/reference/lastPropertyInLiteralWins.errors.txt
index c8844f2c5721f..2b4a694975b4c 100644
--- a/tests/baselines/reference/lastPropertyInLiteralWins.errors.txt
+++ b/tests/baselines/reference/lastPropertyInLiteralWins.errors.txt
@@ -4,12 +4,10 @@ tests/cases/compiler/lastPropertyInLiteralWins.ts(7,6): error TS2345: Argument o
       Types of parameters 'num' and 'str' are incompatible.
         Type 'string' is not assignable to type 'number'.
 tests/cases/compiler/lastPropertyInLiteralWins.ts(9,5): error TS2300: Duplicate identifier 'thunk'.
-tests/cases/compiler/lastPropertyInLiteralWins.ts(9,5): error TS2698: Cannot change type of property 'thunk' from '(str: string) => void' to '(num: number) => void'.
 tests/cases/compiler/lastPropertyInLiteralWins.ts(14,5): error TS2300: Duplicate identifier 'thunk'.
-tests/cases/compiler/lastPropertyInLiteralWins.ts(14,5): error TS2698: Cannot change type of property 'thunk' from '(num: number) => void' to '(str: string) => void'.
 
 
-==== tests/cases/compiler/lastPropertyInLiteralWins.ts (5 errors) ====
+==== tests/cases/compiler/lastPropertyInLiteralWins.ts (3 errors) ====
     interface Thing {
         thunk: (str: string) => void;
     }
@@ -24,8 +22,6 @@ tests/cases/compiler/lastPropertyInLiteralWins.ts(14,5): error TS2698: Cannot ch
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
         ~~~~~
 !!! error TS2300: Duplicate identifier 'thunk'.
-        ~~~~~
-!!! error TS2698: Cannot change type of property 'thunk' from '(str: string) => void' to '(num: number) => void'.
     });
     ~
 !!! error TS2345: Argument of type '{ thunk: (num: number) => void; }' is not assignable to parameter of type 'Thing'.
@@ -39,7 +35,5 @@ tests/cases/compiler/lastPropertyInLiteralWins.ts(14,5): error TS2698: Cannot ch
         thunk: (str: string) => {}
         ~~~~~
 !!! error TS2300: Duplicate identifier 'thunk'.
-        ~~~~~
-!!! error TS2698: Cannot change type of property 'thunk' from '(num: number) => void' to '(str: string) => void'.
     });
     
\ No newline at end of file
diff --git a/tests/baselines/reference/memberOverride.errors.txt b/tests/baselines/reference/memberOverride.errors.txt
index 355db0015057f..15c4b2ad37bb8 100644
--- a/tests/baselines/reference/memberOverride.errors.txt
+++ b/tests/baselines/reference/memberOverride.errors.txt
@@ -1,8 +1,7 @@
 tests/cases/compiler/memberOverride.ts(5,5): error TS2300: Duplicate identifier 'a'.
-tests/cases/compiler/memberOverride.ts(5,5): error TS2698: Cannot change type of property 'a' from 'string' to 'number'.
 
 
-==== tests/cases/compiler/memberOverride.ts (2 errors) ====
+==== tests/cases/compiler/memberOverride.ts (1 errors) ====
     // An object initialiser accepts the first definition for the same property with a different type signature
     // Should compile, since the second declaration of a overrides the first
     var x = {
@@ -10,8 +9,6 @@ tests/cases/compiler/memberOverride.ts(5,5): error TS2698: Cannot change type of
         a: 5
         ~
 !!! error TS2300: Duplicate identifier 'a'.
-        ~
-!!! error TS2698: Cannot change type of property 'a' from 'string' to 'number'.
     }
     
     var n: number = x.a;
\ No newline at end of file
diff --git a/tests/baselines/reference/objectLiteralErrors.errors.txt b/tests/baselines/reference/objectLiteralErrors.errors.txt
index f70f255df05b8..234ac24a8fdc5 100644
--- a/tests/baselines/reference/objectLiteralErrors.errors.txt
+++ b/tests/baselines/reference/objectLiteralErrors.errors.txt
@@ -1,7 +1,6 @@
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(3,18): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(4,19): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(5,18): error TS2300: Duplicate identifier 'a'.
-tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(5,18): error TS2698: Cannot change type of property 'a' from 'number' to 'string'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(6,21): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(7,19): error TS2300: Duplicate identifier 'a'.
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(8,18): error TS2300: Duplicate identifier ''a''.
@@ -79,7 +78,7 @@ tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(45,16)
 tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(45,55): error TS2380: 'get' and 'set' accessor must have the same type.
 
 
-==== tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts (79 errors) ====
+==== tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts (78 errors) ====
     
     // Multiple properties with the same name
     var e1 = { a: 0, a: 0 };
@@ -91,8 +90,6 @@ tests/cases/conformance/expressions/objectLiterals/objectLiteralErrors.ts(45,55)
     var e3 = { a: 0, a: '' };
                      ~
 !!! error TS2300: Duplicate identifier 'a'.
-                     ~
-!!! error TS2698: Cannot change type of property 'a' from 'number' to 'string'.
     var e4 = { a: true, a: false };
                         ~
 !!! error TS2300: Duplicate identifier 'a'.
diff --git a/tests/baselines/reference/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.errors.txt b/tests/baselines/reference/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.errors.txt
index cbe19cab2d25b..5fa8a12e87559 100644
--- a/tests/baselines/reference/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.errors.txt
+++ b/tests/baselines/reference/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.errors.txt
@@ -8,14 +8,12 @@ tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPr
 tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(10,10): error TS1005: ':' expected.
 tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(12,1): error TS1005: ':' expected.
 tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(15,6): error TS1005: ':' expected.
-tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(16,5): error TS2698: Cannot change type of property 'a' from 'any' to 'string[]'.
 tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(16,6): error TS1005: ':' expected.
-tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(17,5): error TS2698: Cannot change type of property 'a' from 'string[]' to 'number[]'.
 tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(17,6): error TS1005: ':' expected.
 tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts(20,17): error TS1005: ':' expected.
 
 
-==== tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts (15 errors) ====
+==== tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.ts (13 errors) ====
     // errors
     var y = {
         "stringLiteral",
@@ -52,13 +50,9 @@ tests/cases/conformance/es6/shorthandPropertyAssignment/objectLiteralShorthandPr
          ~
 !!! error TS1005: ':' expected.
         a["ss"],
-        ~
-!!! error TS2698: Cannot change type of property 'a' from 'any' to 'string[]'.
          ~
 !!! error TS1005: ':' expected.
         a[1],
-        ~
-!!! error TS2698: Cannot change type of property 'a' from 'string[]' to 'number[]'.
          ~
 !!! error TS1005: ':' expected.
     };
diff --git a/tests/baselines/reference/objectSpread.js b/tests/baselines/reference/objectSpread.js
index a59577fe9dece..a09f5aa0fbb1a 100644
--- a/tests/baselines/reference/objectSpread.js
+++ b/tests/baselines/reference/objectSpread.js
@@ -35,11 +35,13 @@ let getter: { a: number, c: number } =
     { ...op, c: 7 }
 getter.a = 12;
 
-// null and undefined are just skipped
-let spreadNull: { a: number } =
-    { a: 7, ...null }
-let spreadUndefined: { a: number } =
-    { a: 7, ...undefined }
+// null, undefined, functions and primitives result in { }
+let spreadNull = { ...null };
+let spreadUndefind = { ...undefined };
+let spreadNum = { ...12 };
+let spreadStr = { ...'foo' };
+let spreadBool = { ...false };
+let spreadFunc = { ...(function () { }) };
 
 // methods are not enumerable
 class C { p = 1; m() { } }
@@ -126,9 +128,13 @@ var propertyNested = __assign({ a: __assign({}, o) });
 var op = { get a() { return 6; } };
 var getter = __assign({}, op, { c: 7 });
 getter.a = 12;
-// null and undefined are just skipped
-var spreadNull = __assign({ a: 7 }, null);
-var spreadUndefined = __assign({ a: 7 }, undefined);
+// null, undefined, functions and primitives result in { }
+var spreadNull = __assign({}, null);
+var spreadUndefind = __assign({}, undefined);
+var spreadNum = __assign({}, 12);
+var spreadStr = __assign({}, 'foo');
+var spreadBool = __assign({}, false);
+var spreadFunc = __assign({}, (function () { }));
 // methods are not enumerable
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/objectSpread.symbols b/tests/baselines/reference/objectSpread.symbols
index 001c42804d2b4..edb0b4c2f0813 100644
--- a/tests/baselines/reference/objectSpread.symbols
+++ b/tests/baselines/reference/objectSpread.symbols
@@ -150,220 +150,224 @@ getter.a = 12;
 >getter : Symbol(getter, Decl(objectSpread.ts, 32, 3))
 >a : Symbol(a, Decl(objectSpread.ts, 32, 13))
 
-// null and undefined are just skipped
-let spreadNull: { a: number } =
+// null, undefined, functions and primitives result in { }
+let spreadNull = { ...null };
 >spreadNull : Symbol(spreadNull, Decl(objectSpread.ts, 37, 3))
->a : Symbol(a, Decl(objectSpread.ts, 37, 17))
 
-    { a: 7, ...null }
->a : Symbol(a, Decl(objectSpread.ts, 38, 5))
+let spreadUndefind = { ...undefined };
+>spreadUndefind : Symbol(spreadUndefind, Decl(objectSpread.ts, 38, 3))
 
-let spreadUndefined: { a: number } =
->spreadUndefined : Symbol(spreadUndefined, Decl(objectSpread.ts, 39, 3))
->a : Symbol(a, Decl(objectSpread.ts, 39, 22))
+let spreadNum = { ...12 };
+>spreadNum : Symbol(spreadNum, Decl(objectSpread.ts, 39, 3))
 
-    { a: 7, ...undefined }
->a : Symbol(a, Decl(objectSpread.ts, 40, 5))
+let spreadStr = { ...'foo' };
+>spreadStr : Symbol(spreadStr, Decl(objectSpread.ts, 40, 3))
+
+let spreadBool = { ...false };
+>spreadBool : Symbol(spreadBool, Decl(objectSpread.ts, 41, 3))
+
+let spreadFunc = { ...(function () { }) };
+>spreadFunc : Symbol(spreadFunc, Decl(objectSpread.ts, 42, 3))
 
 // methods are not enumerable
 class C { p = 1; m() { } }
->C : Symbol(C, Decl(objectSpread.ts, 40, 26))
->p : Symbol(C.p, Decl(objectSpread.ts, 43, 9))
->m : Symbol(C.m, Decl(objectSpread.ts, 43, 16))
+>C : Symbol(C, Decl(objectSpread.ts, 42, 42))
+>p : Symbol(C.p, Decl(objectSpread.ts, 45, 9))
+>m : Symbol(C.m, Decl(objectSpread.ts, 45, 16))
 
 let c: C = new C()
->c : Symbol(c, Decl(objectSpread.ts, 44, 3))
->C : Symbol(C, Decl(objectSpread.ts, 40, 26))
->C : Symbol(C, Decl(objectSpread.ts, 40, 26))
+>c : Symbol(c, Decl(objectSpread.ts, 46, 3))
+>C : Symbol(C, Decl(objectSpread.ts, 42, 42))
+>C : Symbol(C, Decl(objectSpread.ts, 42, 42))
 
 let spreadC: { p: number } = { ...c }
->spreadC : Symbol(spreadC, Decl(objectSpread.ts, 45, 3))
->p : Symbol(p, Decl(objectSpread.ts, 45, 14))
+>spreadC : Symbol(spreadC, Decl(objectSpread.ts, 47, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 47, 14))
 
 // own methods are enumerable
 let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } };
->cplus : Symbol(cplus, Decl(objectSpread.ts, 48, 3))
->p : Symbol(p, Decl(objectSpread.ts, 48, 12))
->plus : Symbol(plus, Decl(objectSpread.ts, 48, 23))
->plus : Symbol(plus, Decl(objectSpread.ts, 48, 48))
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 50, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 50, 12))
+>plus : Symbol(plus, Decl(objectSpread.ts, 50, 23))
+>plus : Symbol(plus, Decl(objectSpread.ts, 50, 48))
 
 cplus.plus();
->cplus.plus : Symbol(plus, Decl(objectSpread.ts, 48, 23))
->cplus : Symbol(cplus, Decl(objectSpread.ts, 48, 3))
->plus : Symbol(plus, Decl(objectSpread.ts, 48, 23))
+>cplus.plus : Symbol(plus, Decl(objectSpread.ts, 50, 23))
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 50, 3))
+>plus : Symbol(plus, Decl(objectSpread.ts, 50, 23))
 
 // new field's type conflicting with existing field is OK
 let changeTypeAfter: { a: string, b: string } =
->changeTypeAfter : Symbol(changeTypeAfter, Decl(objectSpread.ts, 52, 3))
->a : Symbol(a, Decl(objectSpread.ts, 52, 22))
->b : Symbol(b, Decl(objectSpread.ts, 52, 33))
+>changeTypeAfter : Symbol(changeTypeAfter, Decl(objectSpread.ts, 54, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 54, 22))
+>b : Symbol(b, Decl(objectSpread.ts, 54, 33))
 
     { ...o, a: 'wrong type?' }
->a : Symbol(a, Decl(objectSpread.ts, 53, 11))
+>a : Symbol(a, Decl(objectSpread.ts, 55, 11))
 
 let changeTypeBefore: { a: number, b: string } =
->changeTypeBefore : Symbol(changeTypeBefore, Decl(objectSpread.ts, 54, 3))
->a : Symbol(a, Decl(objectSpread.ts, 54, 23))
->b : Symbol(b, Decl(objectSpread.ts, 54, 34))
+>changeTypeBefore : Symbol(changeTypeBefore, Decl(objectSpread.ts, 56, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 56, 23))
+>b : Symbol(b, Decl(objectSpread.ts, 56, 34))
 
     { a: 'wrong type?', ...o };
->a : Symbol(a, Decl(objectSpread.ts, 55, 5))
+>a : Symbol(a, Decl(objectSpread.ts, 57, 5))
 
 let changeTypeBoth: { a: string, b: number } =
->changeTypeBoth : Symbol(changeTypeBoth, Decl(objectSpread.ts, 56, 3))
->a : Symbol(a, Decl(objectSpread.ts, 56, 21))
->b : Symbol(b, Decl(objectSpread.ts, 56, 32))
+>changeTypeBoth : Symbol(changeTypeBoth, Decl(objectSpread.ts, 58, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 58, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 58, 32))
 
     { ...o, ...swap };
 
 // optional
 let definiteBoolean: { sn: boolean };
->definiteBoolean : Symbol(definiteBoolean, Decl(objectSpread.ts, 60, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 60, 22))
+>definiteBoolean : Symbol(definiteBoolean, Decl(objectSpread.ts, 62, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 62, 22))
 
 let definiteString: { sn: string };
->definiteString : Symbol(definiteString, Decl(objectSpread.ts, 61, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 61, 21))
+>definiteString : Symbol(definiteString, Decl(objectSpread.ts, 63, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 63, 21))
 
 let optionalString: { sn?: string };
->optionalString : Symbol(optionalString, Decl(objectSpread.ts, 62, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 62, 21))
+>optionalString : Symbol(optionalString, Decl(objectSpread.ts, 64, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 64, 21))
 
 let optionalNumber: { sn?: number };
->optionalNumber : Symbol(optionalNumber, Decl(objectSpread.ts, 63, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 63, 21))
+>optionalNumber : Symbol(optionalNumber, Decl(objectSpread.ts, 65, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 65, 21))
 
 let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
->optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpread.ts, 64, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 64, 25))
+>optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpread.ts, 66, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 66, 25))
 
 let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
->optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpread.ts, 65, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 65, 30))
+>optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpread.ts, 67, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 67, 30))
 
 let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
->allOptional : Symbol(allOptional, Decl(objectSpread.ts, 66, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 66, 18))
+>allOptional : Symbol(allOptional, Decl(objectSpread.ts, 68, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 68, 18))
 
 // computed property
 let computedFirst: { a: number, b: string, "before everything": number } =
->computedFirst : Symbol(computedFirst, Decl(objectSpread.ts, 69, 3))
->a : Symbol(a, Decl(objectSpread.ts, 69, 20))
->b : Symbol(b, Decl(objectSpread.ts, 69, 31))
+>computedFirst : Symbol(computedFirst, Decl(objectSpread.ts, 71, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 71, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 71, 31))
 
     { ['before everything']: 12, ...o, b: 'yes' }
->'before everything' : Symbol(['before everything'], Decl(objectSpread.ts, 70, 5))
->b : Symbol(b, Decl(objectSpread.ts, 70, 38))
+>'before everything' : Symbol(['before everything'], Decl(objectSpread.ts, 72, 5))
+>b : Symbol(b, Decl(objectSpread.ts, 72, 38))
 
 let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
->computedMiddle : Symbol(computedMiddle, Decl(objectSpread.ts, 71, 3))
->a : Symbol(a, Decl(objectSpread.ts, 71, 21))
->b : Symbol(b, Decl(objectSpread.ts, 71, 32))
->c : Symbol(c, Decl(objectSpread.ts, 71, 43))
+>computedMiddle : Symbol(computedMiddle, Decl(objectSpread.ts, 73, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 73, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 73, 32))
+>c : Symbol(c, Decl(objectSpread.ts, 73, 43))
 
     { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
->'in the middle' : Symbol(['in the middle'], Decl(objectSpread.ts, 72, 11))
->b : Symbol(b, Decl(objectSpread.ts, 72, 34))
+>'in the middle' : Symbol(['in the middle'], Decl(objectSpread.ts, 74, 11))
+>b : Symbol(b, Decl(objectSpread.ts, 74, 34))
 
 let computedAfter: { a: number, b: string, "at the end": number } =
->computedAfter : Symbol(computedAfter, Decl(objectSpread.ts, 73, 3))
->a : Symbol(a, Decl(objectSpread.ts, 73, 20))
->b : Symbol(b, Decl(objectSpread.ts, 73, 31))
+>computedAfter : Symbol(computedAfter, Decl(objectSpread.ts, 75, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 75, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 75, 31))
 
     { ...o, b: 'yeah', ['at the end']: 14 }
->b : Symbol(b, Decl(objectSpread.ts, 74, 11))
->'at the end' : Symbol(['at the end'], Decl(objectSpread.ts, 74, 22))
+>b : Symbol(b, Decl(objectSpread.ts, 76, 11))
+>'at the end' : Symbol(['at the end'], Decl(objectSpread.ts, 76, 22))
 
 // shortcut syntax
 let a = 12;
->a : Symbol(a, Decl(objectSpread.ts, 76, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 78, 3))
 
 let shortCutted: { a: number, b: string } = { ...o, a }
->shortCutted : Symbol(shortCutted, Decl(objectSpread.ts, 77, 3))
->a : Symbol(a, Decl(objectSpread.ts, 77, 18))
->b : Symbol(b, Decl(objectSpread.ts, 77, 29))
->a : Symbol(a, Decl(objectSpread.ts, 77, 51))
+>shortCutted : Symbol(shortCutted, Decl(objectSpread.ts, 79, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 79, 18))
+>b : Symbol(b, Decl(objectSpread.ts, 79, 29))
+>a : Symbol(a, Decl(objectSpread.ts, 79, 51))
 
 // generics
 function f<T, U>(t: T, u: U): { id: string, ...T, ...U } {
->f : Symbol(f, Decl(objectSpread.ts, 77, 55))
->T : Symbol(T, Decl(objectSpread.ts, 80, 11))
->U : Symbol(U, Decl(objectSpread.ts, 80, 13))
->t : Symbol(t, Decl(objectSpread.ts, 80, 17))
->T : Symbol(T, Decl(objectSpread.ts, 80, 11))
->u : Symbol(u, Decl(objectSpread.ts, 80, 22))
->U : Symbol(U, Decl(objectSpread.ts, 80, 13))
->id : Symbol(id, Decl(objectSpread.ts, 80, 31))
->T : Symbol(T, Decl(objectSpread.ts, 80, 11))
->U : Symbol(U, Decl(objectSpread.ts, 80, 13))
+>f : Symbol(f, Decl(objectSpread.ts, 79, 55))
+>T : Symbol(T, Decl(objectSpread.ts, 82, 11))
+>U : Symbol(U, Decl(objectSpread.ts, 82, 13))
+>t : Symbol(t, Decl(objectSpread.ts, 82, 17))
+>T : Symbol(T, Decl(objectSpread.ts, 82, 11))
+>u : Symbol(u, Decl(objectSpread.ts, 82, 22))
+>U : Symbol(U, Decl(objectSpread.ts, 82, 13))
+>id : Symbol(id, Decl(objectSpread.ts, 82, 31))
+>T : Symbol(T, Decl(objectSpread.ts, 82, 11))
+>U : Symbol(U, Decl(objectSpread.ts, 82, 13))
 
     return { id: 'id', ...t, ...u };
->id : Symbol(id, Decl(objectSpread.ts, 81, 12))
+>id : Symbol(id, Decl(objectSpread.ts, 83, 12))
 }
 let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
->exclusive : Symbol(exclusive, Decl(objectSpread.ts, 83, 3))
->id : Symbol(id, Decl(objectSpread.ts, 83, 16))
->a : Symbol(a, Decl(objectSpread.ts, 83, 28))
->b : Symbol(b, Decl(objectSpread.ts, 83, 39))
->c : Symbol(c, Decl(objectSpread.ts, 83, 50))
->d : Symbol(d, Decl(objectSpread.ts, 83, 61))
+>exclusive : Symbol(exclusive, Decl(objectSpread.ts, 85, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 85, 16))
+>a : Symbol(a, Decl(objectSpread.ts, 85, 28))
+>b : Symbol(b, Decl(objectSpread.ts, 85, 39))
+>c : Symbol(c, Decl(objectSpread.ts, 85, 50))
+>d : Symbol(d, Decl(objectSpread.ts, 85, 61))
 
     f({ a: 1, b: 'yes' }, { c: 'no', d: false })
->f : Symbol(f, Decl(objectSpread.ts, 77, 55))
->a : Symbol(a, Decl(objectSpread.ts, 84, 7))
->b : Symbol(b, Decl(objectSpread.ts, 84, 13))
->c : Symbol(c, Decl(objectSpread.ts, 84, 27))
->d : Symbol(d, Decl(objectSpread.ts, 84, 36))
+>f : Symbol(f, Decl(objectSpread.ts, 79, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 86, 7))
+>b : Symbol(b, Decl(objectSpread.ts, 86, 13))
+>c : Symbol(c, Decl(objectSpread.ts, 86, 27))
+>d : Symbol(d, Decl(objectSpread.ts, 86, 36))
 
 let overlap: { id: string, a: number, b: string } =
->overlap : Symbol(overlap, Decl(objectSpread.ts, 85, 3))
->id : Symbol(id, Decl(objectSpread.ts, 85, 14))
->a : Symbol(a, Decl(objectSpread.ts, 85, 26))
->b : Symbol(b, Decl(objectSpread.ts, 85, 37))
+>overlap : Symbol(overlap, Decl(objectSpread.ts, 87, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 87, 14))
+>a : Symbol(a, Decl(objectSpread.ts, 87, 26))
+>b : Symbol(b, Decl(objectSpread.ts, 87, 37))
 
     f({ a: 1 }, { a: 2, b: 'extra' })
->f : Symbol(f, Decl(objectSpread.ts, 77, 55))
->a : Symbol(a, Decl(objectSpread.ts, 86, 7))
->a : Symbol(a, Decl(objectSpread.ts, 86, 17))
->b : Symbol(b, Decl(objectSpread.ts, 86, 23))
+>f : Symbol(f, Decl(objectSpread.ts, 79, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 88, 7))
+>a : Symbol(a, Decl(objectSpread.ts, 88, 17))
+>b : Symbol(b, Decl(objectSpread.ts, 88, 23))
 
 let overlapConflict: { id:string, a: string } =
->overlapConflict : Symbol(overlapConflict, Decl(objectSpread.ts, 87, 3))
->id : Symbol(id, Decl(objectSpread.ts, 87, 22))
->a : Symbol(a, Decl(objectSpread.ts, 87, 33))
+>overlapConflict : Symbol(overlapConflict, Decl(objectSpread.ts, 89, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 89, 22))
+>a : Symbol(a, Decl(objectSpread.ts, 89, 33))
 
     f({ a: 1 }, { a: 'mismatch' })
->f : Symbol(f, Decl(objectSpread.ts, 77, 55))
->a : Symbol(a, Decl(objectSpread.ts, 88, 7))
->a : Symbol(a, Decl(objectSpread.ts, 88, 17))
+>f : Symbol(f, Decl(objectSpread.ts, 79, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 90, 7))
+>a : Symbol(a, Decl(objectSpread.ts, 90, 17))
 
 let overwriteId: { id: boolean, a: number, c: number, d: string } =
->overwriteId : Symbol(overwriteId, Decl(objectSpread.ts, 89, 3))
->id : Symbol(id, Decl(objectSpread.ts, 89, 18))
->a : Symbol(a, Decl(objectSpread.ts, 89, 31))
->c : Symbol(c, Decl(objectSpread.ts, 89, 42))
->d : Symbol(d, Decl(objectSpread.ts, 89, 53))
+>overwriteId : Symbol(overwriteId, Decl(objectSpread.ts, 91, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 91, 18))
+>a : Symbol(a, Decl(objectSpread.ts, 91, 31))
+>c : Symbol(c, Decl(objectSpread.ts, 91, 42))
+>d : Symbol(d, Decl(objectSpread.ts, 91, 53))
 
     f({ a: 1, id: true }, { c: 1, d: 'no' })
->f : Symbol(f, Decl(objectSpread.ts, 77, 55))
->a : Symbol(a, Decl(objectSpread.ts, 90, 7))
->id : Symbol(id, Decl(objectSpread.ts, 90, 13))
->c : Symbol(c, Decl(objectSpread.ts, 90, 27))
->d : Symbol(d, Decl(objectSpread.ts, 90, 33))
+>f : Symbol(f, Decl(objectSpread.ts, 79, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 92, 7))
+>id : Symbol(id, Decl(objectSpread.ts, 92, 13))
+>c : Symbol(c, Decl(objectSpread.ts, 92, 27))
+>d : Symbol(d, Decl(objectSpread.ts, 92, 33))
 
 class D { m() { }; q = 2; }
->D : Symbol(D, Decl(objectSpread.ts, 90, 44))
->m : Symbol(D.m, Decl(objectSpread.ts, 92, 9))
->q : Symbol(D.q, Decl(objectSpread.ts, 92, 18))
+>D : Symbol(D, Decl(objectSpread.ts, 92, 44))
+>m : Symbol(D.m, Decl(objectSpread.ts, 94, 9))
+>q : Symbol(D.q, Decl(objectSpread.ts, 94, 18))
 
 let classesAreWrong: { id: string, ...C, ...D } =
->classesAreWrong : Symbol(classesAreWrong, Decl(objectSpread.ts, 93, 3))
->id : Symbol(id, Decl(objectSpread.ts, 93, 22))
->C : Symbol(C, Decl(objectSpread.ts, 40, 26))
->D : Symbol(D, Decl(objectSpread.ts, 90, 44))
+>classesAreWrong : Symbol(classesAreWrong, Decl(objectSpread.ts, 95, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 95, 22))
+>C : Symbol(C, Decl(objectSpread.ts, 42, 42))
+>D : Symbol(D, Decl(objectSpread.ts, 92, 44))
 
     f(new C(), new D())
->f : Symbol(f, Decl(objectSpread.ts, 77, 55))
->C : Symbol(C, Decl(objectSpread.ts, 40, 26))
->D : Symbol(D, Decl(objectSpread.ts, 90, 44))
+>f : Symbol(f, Decl(objectSpread.ts, 79, 55))
+>C : Symbol(C, Decl(objectSpread.ts, 42, 42))
+>D : Symbol(D, Decl(objectSpread.ts, 92, 44))
 
diff --git a/tests/baselines/reference/objectSpread.types b/tests/baselines/reference/objectSpread.types
index 86d04eb4588be..2b13af1d3d6e7 100644
--- a/tests/baselines/reference/objectSpread.types
+++ b/tests/baselines/reference/objectSpread.types
@@ -223,27 +223,36 @@ getter.a = 12;
 >a : number
 >12 : 12
 
-// null and undefined are just skipped
-let spreadNull: { a: number } =
->spreadNull : { a: number; }
->a : number
-
-    { a: 7, ...null }
->{ a: 7, ...null } : { a: number; }
->a : number
->7 : 7
+// null, undefined, functions and primitives result in { }
+let spreadNull = { ...null };
+>spreadNull : {}
+>{ ...null } : {}
 >null : null
 
-let spreadUndefined: { a: number } =
->spreadUndefined : { a: number; }
->a : number
-
-    { a: 7, ...undefined }
->{ a: 7, ...undefined } : { a: number; }
->a : number
->7 : 7
+let spreadUndefind = { ...undefined };
+>spreadUndefind : {}
+>{ ...undefined } : {}
 >undefined : any
 
+let spreadNum = { ...12 };
+>spreadNum : {}
+>{ ...12 } : {}
+
+let spreadStr = { ...'foo' };
+>spreadStr : {}
+>{ ...'foo' } : {}
+
+let spreadBool = { ...false };
+>spreadBool : {}
+>{ ...false } : {}
+>false : false
+
+let spreadFunc = { ...(function () { }) };
+>spreadFunc : {}
+>{ ...(function () { }) } : {}
+>(function () { }) : () => void
+>function () { } : () => void
+
 // methods are not enumerable
 class C { p = 1; m() { } }
 >C : C
diff --git a/tests/baselines/reference/objectSpreadIntersection.js b/tests/baselines/reference/objectSpreadIntersection.js
new file mode 100644
index 0000000000000..cb93c54796334
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadIntersection.js
@@ -0,0 +1,79 @@
+//// [objectSpreadIntersection.ts]
+function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
+    let tu: T | U;
+    let uv: U & V;
+    let result = { id: 'bar', ...tu, ...uv };
+    let expected: ({ id: string, ...T, ...U } & { id: string, ...T, ...V }) | ({ id: string, ...U } & { id: string, ...U, ...V });
+    let assignable: { id: string, ...(T | U), ...(U & V) } = result;
+}
+// concrete types work
+interface A1 { a: number }
+interface A2 { a: string }
+let a12: A1 & A2;
+let result = { ...a12 };
+let sn: number & string = result.a;
+let assignable: { ...(A1 & A2) } = result;
+
+function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
+    let tuv: T & U & V;
+    let result = { id: 'foo', ...tuv };
+    let expected: { id: string, ...T } & { id: string, ...U } & { id: string, ...V } = result;
+    let assignable: { id: string, ...(T & U & V) } = result;
+}
+function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
+    let tu: T & U;
+    let uv: U & V;
+    let result = { id: 'bar', ...tu, ...uv };
+    let expected: { id: string, ...T, ...U } & { id: string, ...T, ...V } & { id: string, ...U } & { id: string, ...U, ...V };
+    let assignable: { id: string, ...(T & U), ...(U & V) } = result;
+}
+function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
+    let tu: T & U;
+    let uv: U | V;
+    let result = { id: 'bar', ...tu, ...uv };
+    let expected: ({ id: string, ...T, ...U } & { id: string, ...U }) | ({ id: string, ...T, ...V } & { id: string, ...U, ...V });
+    let assignable: { id: string, ...(T & U), ...(U | V) } = result;
+}
+
+
+
+//// [objectSpreadIntersection.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+function iteratedUnionIntersection(t, u, v) {
+    var tu;
+    var uv;
+    var result = __assign({ id: 'bar' }, tu, uv);
+    var expected;
+    var assignable = result;
+}
+var a12;
+var result = __assign({}, a12);
+var sn = result.a;
+var assignable = result;
+function tripleIntersection(t, u, v) {
+    var tuv;
+    var result = __assign({ id: 'foo' }, tuv);
+    var expected = result;
+    var assignable = result;
+}
+function iteratedDoubleIntersection(t, u, v) {
+    var tu;
+    var uv;
+    var result = __assign({ id: 'bar' }, tu, uv);
+    var expected;
+    var assignable = result;
+}
+function iteratedIntersectionUnion(t, u, v) {
+    var tu;
+    var uv;
+    var result = __assign({ id: 'bar' }, tu, uv);
+    var expected;
+    var assignable = result;
+}
diff --git a/tests/baselines/reference/objectSpreadIntersection.symbols b/tests/baselines/reference/objectSpreadIntersection.symbols
new file mode 100644
index 0000000000000..f45b04a20a51c
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadIntersection.symbols
@@ -0,0 +1,219 @@
+=== tests/cases/conformance/types/spread/objectSpreadIntersection.ts ===
+function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
+>iteratedUnionIntersection : Symbol(iteratedUnionIntersection, Decl(objectSpreadIntersection.ts, 0, 0))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 0, 44))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 0, 49))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 0, 55))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
+
+    let tu: T | U;
+>tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 1, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+
+    let uv: U & V;
+>uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 2, 7))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
+
+    let result = { id: 'bar', ...tu, ...uv };
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 3, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 3, 18))
+
+    let expected: ({ id: string, ...T, ...U } & { id: string, ...T, ...V }) | ({ id: string, ...U } & { id: string, ...U, ...V });
+>expected : Symbol(expected, Decl(objectSpreadIntersection.ts, 4, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 20))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 49))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 80))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 103))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
+
+    let assignable: { id: string, ...(T | U), ...(U & V) } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 5, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 5, 21))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 3, 7))
+}
+// concrete types work
+interface A1 { a: number }
+>A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 6, 1))
+>a : Symbol(A1.a, Decl(objectSpreadIntersection.ts, 8, 14))
+
+interface A2 { a: string }
+>A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 8, 26))
+>a : Symbol(A2.a, Decl(objectSpreadIntersection.ts, 9, 14))
+
+let a12: A1 & A2;
+>a12 : Symbol(a12, Decl(objectSpreadIntersection.ts, 10, 3))
+>A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 6, 1))
+>A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 8, 26))
+
+let result = { ...a12 };
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 11, 3))
+
+let sn: number & string = result.a;
+>sn : Symbol(sn, Decl(objectSpreadIntersection.ts, 12, 3))
+>result.a : Symbol(a, Decl(objectSpreadIntersection.ts, 8, 14), Decl(objectSpreadIntersection.ts, 9, 14))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 11, 3))
+>a : Symbol(a, Decl(objectSpreadIntersection.ts, 8, 14), Decl(objectSpreadIntersection.ts, 9, 14))
+
+let assignable: { ...(A1 & A2) } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 13, 3))
+>A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 6, 1))
+>A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 8, 26))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 11, 3))
+
+function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
+>tripleIntersection : Symbol(tripleIntersection, Decl(objectSpreadIntersection.ts, 13, 42))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 15, 28))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 15, 37))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 15, 28))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 15, 42))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 15, 48))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
+
+    let tuv: T & U & V;
+>tuv : Symbol(tuv, Decl(objectSpreadIntersection.ts, 16, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 15, 28))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
+
+    let result = { id: 'foo', ...tuv };
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 17, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 17, 18))
+
+    let expected: { id: string, ...T } & { id: string, ...U } & { id: string, ...V } = result;
+>expected : Symbol(expected, Decl(objectSpreadIntersection.ts, 18, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 18, 19))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 15, 28))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 18, 42))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 18, 65))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 17, 7))
+
+    let assignable: { id: string, ...(T & U & V) } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 19, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 19, 21))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 15, 28))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 17, 7))
+}
+function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
+>iteratedDoubleIntersection : Symbol(iteratedDoubleIntersection, Decl(objectSpreadIntersection.ts, 20, 1))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 21, 45))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 21, 50))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 21, 56))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
+
+    let tu: T & U;
+>tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 22, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
+
+    let uv: U & V;
+>uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 23, 7))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
+
+    let result = { id: 'bar', ...tu, ...uv };
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 24, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 24, 18))
+
+    let expected: { id: string, ...T, ...U } & { id: string, ...T, ...V } & { id: string, ...U } & { id: string, ...U, ...V };
+>expected : Symbol(expected, Decl(objectSpreadIntersection.ts, 25, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 19))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 48))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 77))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 100))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
+
+    let assignable: { id: string, ...(T & U), ...(U & V) } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 26, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 26, 21))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 24, 7))
+}
+function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
+>iteratedIntersectionUnion : Symbol(iteratedIntersectionUnion, Decl(objectSpreadIntersection.ts, 27, 1))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 28, 44))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 28, 49))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 28, 55))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
+
+    let tu: T & U;
+>tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 29, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
+
+    let uv: U | V;
+>uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 30, 7))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
+
+    let result = { id: 'bar', ...tu, ...uv };
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 31, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 31, 18))
+
+    let expected: ({ id: string, ...T, ...U } & { id: string, ...U }) | ({ id: string, ...T, ...V } & { id: string, ...U, ...V });
+>expected : Symbol(expected, Decl(objectSpreadIntersection.ts, 32, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 20))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 49))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 74))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 103))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
+
+    let assignable: { id: string, ...(T & U), ...(U | V) } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 33, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 33, 21))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 31, 7))
+}
+
+
diff --git a/tests/baselines/reference/objectSpreadIntersection.types b/tests/baselines/reference/objectSpreadIntersection.types
new file mode 100644
index 0000000000000..7700d8aa384d3
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadIntersection.types
@@ -0,0 +1,236 @@
+=== tests/cases/conformance/types/spread/objectSpreadIntersection.ts ===
+function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
+>iteratedUnionIntersection : <T, U, V>(t: T, u: U, v: V) => void
+>T : T
+>U : U
+>V : V
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+    let tu: T | U;
+>tu : T | U
+>T : T
+>U : U
+
+    let uv: U & V;
+>uv : U & V
+>U : U
+>V : V
+
+    let result = { id: 'bar', ...tu, ...uv };
+>result : ({ id: string; ...T; ...U } | { id: string; ...U }) & ({ id: string; ...T; ...V } | { id: string; ...U; ...V })
+>{ id: 'bar', ...tu, ...uv } : ({ id: string; ...T; ...U } | { id: string; ...U }) & ({ id: string; ...T; ...V } | { id: string; ...U; ...V })
+>id : string
+>'bar' : "bar"
+>tu : any
+>uv : any
+
+    let expected: ({ id: string, ...T, ...U } & { id: string, ...T, ...V }) | ({ id: string, ...U } & { id: string, ...U, ...V });
+>expected : ({ id: string; ...T; ...U } & { id: string; ...T; ...V }) | ({ id: string; ...U } & { id: string; ...U; ...V })
+>id : string
+>T : T
+>U : U
+>id : string
+>T : T
+>V : V
+>id : string
+>U : U
+>id : string
+>U : U
+>V : V
+
+    let assignable: { id: string, ...(T | U), ...(U & V) } = result;
+>assignable : ({ id: string; ...T; ...U } | { id: string; ...U }) & ({ id: string; ...T; ...V } | { id: string; ...U; ...V })
+>id : string
+>T : T
+>U : U
+>U : U
+>V : V
+>result : ({ id: string; ...T; ...U } | { id: string; ...U }) & ({ id: string; ...T; ...V } | { id: string; ...U; ...V })
+}
+// concrete types work
+interface A1 { a: number }
+>A1 : A1
+>a : number
+
+interface A2 { a: string }
+>A2 : A2
+>a : string
+
+let a12: A1 & A2;
+>a12 : A1 & A2
+>A1 : A1
+>A2 : A2
+
+let result = { ...a12 };
+>result : { a: number; } & { a: string; }
+>{ ...a12 } : { a: number; } & { a: string; }
+>a12 : any
+
+let sn: number & string = result.a;
+>sn : number & string
+>result.a : number & string
+>result : { a: number; } & { a: string; }
+>a : number & string
+
+let assignable: { ...(A1 & A2) } = result;
+>assignable : { a: number; } & { a: string; }
+>A1 : A1
+>A2 : A2
+>result : { a: number; } & { a: string; }
+
+function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
+>tripleIntersection : <T, U, V>(t: T, u: U, v: V) => void
+>T : T
+>U : U
+>V : V
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+    let tuv: T & U & V;
+>tuv : T & U & V
+>T : T
+>U : U
+>V : V
+
+    let result = { id: 'foo', ...tuv };
+>result : { id: string; ...T } & { id: string; ...U } & { id: string; ...V }
+>{ id: 'foo', ...tuv } : { id: string; ...T } & { id: string; ...U } & { id: string; ...V }
+>id : string
+>'foo' : "foo"
+>tuv : any
+
+    let expected: { id: string, ...T } & { id: string, ...U } & { id: string, ...V } = result;
+>expected : { id: string; ...T } & { id: string; ...U } & { id: string; ...V }
+>id : string
+>T : T
+>id : string
+>U : U
+>id : string
+>V : V
+>result : { id: string; ...T } & { id: string; ...U } & { id: string; ...V }
+
+    let assignable: { id: string, ...(T & U & V) } = result;
+>assignable : { id: string; ...T } & { id: string; ...U } & { id: string; ...V }
+>id : string
+>T : T
+>U : U
+>V : V
+>result : { id: string; ...T } & { id: string; ...U } & { id: string; ...V }
+}
+function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
+>iteratedDoubleIntersection : <T, U, V>(t: T, u: U, v: V) => void
+>T : T
+>U : U
+>V : V
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+    let tu: T & U;
+>tu : T & U
+>T : T
+>U : U
+
+    let uv: U & V;
+>uv : U & V
+>U : U
+>V : V
+
+    let result = { id: 'bar', ...tu, ...uv };
+>result : { id: string; ...T; ...U } & { id: string; ...U } & { id: string; ...T; ...V } & { id: string; ...U; ...V }
+>{ id: 'bar', ...tu, ...uv } : { id: string; ...T; ...U } & { id: string; ...U } & { id: string; ...T; ...V } & { id: string; ...U; ...V }
+>id : string
+>'bar' : "bar"
+>tu : any
+>uv : any
+
+    let expected: { id: string, ...T, ...U } & { id: string, ...T, ...V } & { id: string, ...U } & { id: string, ...U, ...V };
+>expected : { id: string; ...T; ...U } & { id: string; ...T; ...V } & { id: string; ...U } & { id: string; ...U; ...V }
+>id : string
+>T : T
+>U : U
+>id : string
+>T : T
+>V : V
+>id : string
+>U : U
+>id : string
+>U : U
+>V : V
+
+    let assignable: { id: string, ...(T & U), ...(U & V) } = result;
+>assignable : { id: string; ...T; ...U } & { id: string; ...U } & { id: string; ...T; ...V } & { id: string; ...U; ...V }
+>id : string
+>T : T
+>U : U
+>U : U
+>V : V
+>result : { id: string; ...T; ...U } & { id: string; ...U } & { id: string; ...T; ...V } & { id: string; ...U; ...V }
+}
+function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
+>iteratedIntersectionUnion : <T, U, V>(t: T, u: U, v: V) => void
+>T : T
+>U : U
+>V : V
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+    let tu: T & U;
+>tu : T & U
+>T : T
+>U : U
+
+    let uv: U | V;
+>uv : U | V
+>U : U
+>V : V
+
+    let result = { id: 'bar', ...tu, ...uv };
+>result : ({ id: string; ...T; ...U } & { id: string; ...U }) | ({ id: string; ...T; ...V } & { id: string; ...U; ...V })
+>{ id: 'bar', ...tu, ...uv } : ({ id: string; ...T; ...U } & { id: string; ...U }) | ({ id: string; ...T; ...V } & { id: string; ...U; ...V })
+>id : string
+>'bar' : "bar"
+>tu : any
+>uv : any
+
+    let expected: ({ id: string, ...T, ...U } & { id: string, ...U }) | ({ id: string, ...T, ...V } & { id: string, ...U, ...V });
+>expected : ({ id: string; ...T; ...U } & { id: string; ...U }) | ({ id: string; ...T; ...V } & { id: string; ...U; ...V })
+>id : string
+>T : T
+>U : U
+>id : string
+>U : U
+>id : string
+>T : T
+>V : V
+>id : string
+>U : U
+>V : V
+
+    let assignable: { id: string, ...(T & U), ...(U | V) } = result;
+>assignable : ({ id: string; ...T; ...U } & { id: string; ...U }) | ({ id: string; ...T; ...V } & { id: string; ...U; ...V })
+>id : string
+>T : T
+>U : U
+>U : U
+>V : V
+>result : ({ id: string; ...T; ...U } & { id: string; ...U }) | ({ id: string; ...T; ...V } & { id: string; ...U; ...V })
+}
+
+
diff --git a/tests/baselines/reference/objectSpreadNegative.errors.txt b/tests/baselines/reference/objectSpreadNegative.errors.txt
index 38e564c3b5d4f..84fb1cc4a76c1 100644
--- a/tests/baselines/reference/objectSpreadNegative.errors.txt
+++ b/tests/baselines/reference/objectSpreadNegative.errors.txt
@@ -5,19 +5,23 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(20,5): error TS2322
   Property 'b' is missing in type '{ s: string; }'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(22,1): error TS2322: Type 'Bool' is not assignable to type '{ s: string; b: boolean; }'.
   Property 's' is missing in type 'Bool'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(25,15): error TS2697: Spread properties must be identifiers, property accesses, or object literals.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(26,15): error TS2697: Spread properties must be identifiers, property accesses, or object literals.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(29,36): error TS2300: Duplicate identifier 'b'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(29,53): error TS2300: Duplicate identifier 'b'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(34,12): error TS2339: Property 'b' does not exist on type '{}'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(40,9): error TS2339: Property 'm' does not exist on type '{ p: number; }'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(43,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ x: number; }' has no compatible call signatures.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(44,1): error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(47,39): error TS2697: Spread properties must be identifiers, property accesses, or object literals.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(51,12): error TS2322: Type '{ ...U }' is not assignable to type 'U'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(25,36): error TS2300: Duplicate identifier 'b'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(25,53): error TS2300: Duplicate identifier 'b'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(30,12): error TS2339: Property 'null' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(32,17): error TS2339: Property 'undefined' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(36,11): error TS2339: Property 'toFixed' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(38,11): error TS2339: Property 'toFixed' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(40,11): error TS2339: Property 'length' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(41,11): error TS2339: Property 'charAt' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(45,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{}' has no compatible call signatures.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(49,12): error TS2339: Property 'b' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(55,9): error TS2339: Property 'm' does not exist on type '{ p: number; }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(58,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ x: number; }' has no compatible call signatures.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(59,1): error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(63,12): error TS2322: Type '{ ...U }' is not assignable to type 'U'.
 
 
-==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (14 errors) ====
+==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (18 errors) ====
     let o = { a: 1, b: 'no' }
     
     /// private propagates
@@ -27,8 +31,8 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(51,12): error TS232
     class PublicX {
         public x: number;
     }
-    let o3: { ...PublicX, ...PrivateOptionalX };
-    let sn: number = o3.x; // error, x is private
+    let o2: { ...PublicX, ...PrivateOptionalX };
+    let sn: number = o2.x; // error, x is private
                         ~
 !!! error TS2339: Property 'x' does not exist on type '{}'.
     let optionalString: { sn?: string };
@@ -52,14 +56,6 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(51,12): error TS232
 !!! error TS2322: Type 'Bool' is not assignable to type '{ s: string; b: boolean; }'.
 !!! error TS2322:   Property 's' is missing in type 'Bool'.
     
-    // expressions are not allowed
-    let o1 = { ...1 + 1 };
-                  ~~~~~
-!!! error TS2697: Spread properties must be identifiers, property accesses, or object literals.
-    let o2 = { ...(1 + 1) };
-                  ~~~~~~~
-!!! error TS2697: Spread properties must be identifiers, property accesses, or object literals.
-    
     // literal repeats are not allowed, but spread repeats are fine
     let duplicated = { b: 'bad', ...o, b: 'bad', ...o2, b: 'bad' }
                                        ~
@@ -68,6 +64,39 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(51,12): error TS232
 !!! error TS2300: Duplicate identifier 'b'.
     let duplicatedSpread = { ...o, ...o }
     
+    // null and undefined are just skipped
+    let spreadNull = { ...null }
+    spreadNull.null;
+               ~~~~
+!!! error TS2339: Property 'null' does not exist on type '{}'.
+    let spreadUndefined = { ...undefined }
+    spreadUndefined.undefined;
+                    ~~~~~~~~~
+!!! error TS2339: Property 'undefined' does not exist on type '{}'.
+    
+    // primitives and functions are skipped
+    let spreadNum = { ...12 };
+    spreadNum.toFixed(); // error, no methods from number
+              ~~~~~~~
+!!! error TS2339: Property 'toFixed' does not exist on type '{}'.
+    let spreadSum = { ...1 + 1 };
+    spreadSum.toFixed(); // error, no methods from number
+              ~~~~~~~
+!!! error TS2339: Property 'toFixed' does not exist on type '{}'.
+    let spreadStr = { ...'foo' };
+    spreadStr.length; // error, no 'length'
+              ~~~~~~
+!!! error TS2339: Property 'length' does not exist on type '{}'.
+    spreadStr.charAt(1); // error, no methods either
+              ~~~~~~
+!!! error TS2339: Property 'charAt' does not exist on type '{}'.
+    let spreadBool = { ...true };
+    spreadBool.valueOf(); // error, what were you thinking?
+    let spreadFunc = { ...function () { } }
+    spreadFunc(); // error, no call signature
+    ~~~~~~~~~~~~
+!!! error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{}' has no compatible call signatures.
+    
     // write-only properties get skipped
     let setterOnly = { ...{ set b (bad: number) { } } };
     setterOnly.b = 12; // error, 'b' does not exist
@@ -90,11 +119,6 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(51,12): error TS232
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
     
-    let publicx: PublicX;
-    let callableSpread = { ...publicx, ...(n => n + 1) }; // error, can't spread functions
-                                          ~~~~~~~~~~~~
-!!! error TS2697: Spread properties must be identifiers, property accesses, or object literals.
-    
     // { ...U } is not assignable to U
     function override<U>(initial: U, override: U): U {
         return { ...initial, ...override };
diff --git a/tests/baselines/reference/objectSpreadNegative.js b/tests/baselines/reference/objectSpreadNegative.js
index 6874380599b61..452ec457e9ae3 100644
--- a/tests/baselines/reference/objectSpreadNegative.js
+++ b/tests/baselines/reference/objectSpreadNegative.js
@@ -8,8 +8,8 @@ class PrivateOptionalX {
 class PublicX {
     public x: number;
 }
-let o3: { ...PublicX, ...PrivateOptionalX };
-let sn: number = o3.x; // error, x is private
+let o2: { ...PublicX, ...PrivateOptionalX };
+let sn: number = o2.x; // error, x is private
 let optionalString: { sn?: string };
 let optionalNumber: { sn?: number };
 let allOptional: { sn: string | number } = { ...optionalString, ...optionalNumber };
@@ -22,14 +22,29 @@ let spread: { ...Bool, ...Str } = { s: 'foo' }; // error, missing 'b'
 let b: Bool;
 spread = b; // error, missing 's'
 
-// expressions are not allowed
-let o1 = { ...1 + 1 };
-let o2 = { ...(1 + 1) };
-
 // literal repeats are not allowed, but spread repeats are fine
 let duplicated = { b: 'bad', ...o, b: 'bad', ...o2, b: 'bad' }
 let duplicatedSpread = { ...o, ...o }
 
+// null and undefined are just skipped
+let spreadNull = { ...null }
+spreadNull.null;
+let spreadUndefined = { ...undefined }
+spreadUndefined.undefined;
+
+// primitives and functions are skipped
+let spreadNum = { ...12 };
+spreadNum.toFixed(); // error, no methods from number
+let spreadSum = { ...1 + 1 };
+spreadSum.toFixed(); // error, no methods from number
+let spreadStr = { ...'foo' };
+spreadStr.length; // error, no 'length'
+spreadStr.charAt(1); // error, no methods either
+let spreadBool = { ...true };
+spreadBool.valueOf(); // error, what were you thinking?
+let spreadFunc = { ...function () { } }
+spreadFunc(); // error, no call signature
+
 // write-only properties get skipped
 let setterOnly = { ...{ set b (bad: number) { } } };
 setterOnly.b = 12; // error, 'b' does not exist
@@ -44,9 +59,6 @@ let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: numb
 callableConstructableSpread(12); // error, no call signature
 new callableConstructableSpread(12); // error, no construct signature
 
-let publicx: PublicX;
-let callableSpread = { ...publicx, ...(n => n + 1) }; // error, can't spread functions
-
 // { ...U } is not assignable to U
 function override<U>(initial: U, override: U): U {
     return { ...initial, ...override };
@@ -74,8 +86,8 @@ var PublicX = (function () {
     }
     return PublicX;
 }());
-var o3;
-var sn = o3.x; // error, x is private
+var o2;
+var sn = o2.x; // error, x is private
 var optionalString;
 var optionalNumber;
 var allOptional = __assign({}, optionalString, optionalNumber);
@@ -84,12 +96,26 @@ var allOptional = __assign({}, optionalString, optionalNumber);
 var spread = { s: 'foo' }; // error, missing 'b'
 var b;
 spread = b; // error, missing 's'
-// expressions are not allowed
-var o1 = __assign({}, 1 + 1);
-var o2 = __assign({}, (1 + 1));
 // literal repeats are not allowed, but spread repeats are fine
 var duplicated = __assign({ b: 'bad' }, o, { b: 'bad' }, o2, { b: 'bad' });
 var duplicatedSpread = __assign({}, o, o);
+// null and undefined are just skipped
+var spreadNull = __assign({}, null);
+spreadNull.null;
+var spreadUndefined = __assign({}, undefined);
+spreadUndefined.undefined;
+// primitives and functions are skipped
+var spreadNum = __assign({}, 12);
+spreadNum.toFixed(); // error, no methods from number
+var spreadSum = __assign({}, 1 + 1);
+spreadSum.toFixed(); // error, no methods from number
+var spreadStr = __assign({}, 'foo');
+spreadStr.length; // error, no 'length'
+spreadStr.charAt(1); // error, no methods either
+var spreadBool = __assign({}, true);
+spreadBool.valueOf(); // error, what were you thinking?
+var spreadFunc = __assign({}, function () { });
+spreadFunc(); // error, no call signature
 // write-only properties get skipped
 var setterOnly = __assign({ set b(bad: number) { } });
 setterOnly.b = 12; // error, 'b' does not exist
@@ -107,8 +133,6 @@ spreadC.m(); // error 'm' is not in '{ ... c }'
 var callableConstructableSpread;
 callableConstructableSpread(12); // error, no call signature
 new callableConstructableSpread(12); // error, no construct signature
-var publicx;
-var callableSpread = __assign({}, publicx, (function (n) { return n + 1; })); // error, can't spread functions
 // { ...U } is not assignable to U
 function override(initial, override) {
     return __assign({}, initial, override);
diff --git a/tests/baselines/reference/objectSpreadUnion.js b/tests/baselines/reference/objectSpreadUnion.js
new file mode 100644
index 0000000000000..500b8a5ddc7ca
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadUnion.js
@@ -0,0 +1,52 @@
+//// [objectSpreadUnion.ts]
+// concrete types work
+interface A1 { a: number }
+interface A2 { a: string }
+let a12: A1 | A2;
+let result = { ...a12 };
+let sn: number | string = result.a;
+let assignable: { ...(A1 | A2) } = result;
+
+function tripleUnion<T, U, V>(t: T, u: U, v: V): void {
+    let tuv: T | U | V;
+    let result = { id: 'foo', ...tuv };
+    let expected: { id: string, ...T } | { id: string, ...U } | { id: string, ...V } = result;
+    let assignable: { id: string, ...(T | U | V) } = result;
+}
+function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
+    let tu: T | U;
+    let uv: U | V;
+    let result = { id: 'bar', ...tu, ...uv };
+    let expected: { id: string, ...T, ...U } | { id: string, ...T, ...V } | { id: string, ...U } | { id: string, ...U, ...V };
+    let assignable: { id: string, ...(T | U), ...(U | V) } = result;
+}
+
+
+
+
+//// [objectSpreadUnion.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+var a12;
+var result = __assign({}, a12);
+var sn = result.a;
+var assignable = result;
+function tripleUnion(t, u, v) {
+    var tuv;
+    var result = __assign({ id: 'foo' }, tuv);
+    var expected = result;
+    var assignable = result;
+}
+function iteratedDoubleUnion(t, u, v) {
+    var tu;
+    var uv;
+    var result = __assign({ id: 'bar' }, tu, uv);
+    var expected;
+    var assignable = result;
+}
diff --git a/tests/baselines/reference/objectSpreadUnion.symbols b/tests/baselines/reference/objectSpreadUnion.symbols
new file mode 100644
index 0000000000000..eea9e65185d0a
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadUnion.symbols
@@ -0,0 +1,122 @@
+=== tests/cases/conformance/types/spread/objectSpreadUnion.ts ===
+// concrete types work
+interface A1 { a: number }
+>A1 : Symbol(A1, Decl(objectSpreadUnion.ts, 0, 0))
+>a : Symbol(A1.a, Decl(objectSpreadUnion.ts, 1, 14))
+
+interface A2 { a: string }
+>A2 : Symbol(A2, Decl(objectSpreadUnion.ts, 1, 26))
+>a : Symbol(A2.a, Decl(objectSpreadUnion.ts, 2, 14))
+
+let a12: A1 | A2;
+>a12 : Symbol(a12, Decl(objectSpreadUnion.ts, 3, 3))
+>A1 : Symbol(A1, Decl(objectSpreadUnion.ts, 0, 0))
+>A2 : Symbol(A2, Decl(objectSpreadUnion.ts, 1, 26))
+
+let result = { ...a12 };
+>result : Symbol(result, Decl(objectSpreadUnion.ts, 4, 3))
+
+let sn: number | string = result.a;
+>sn : Symbol(sn, Decl(objectSpreadUnion.ts, 5, 3))
+>result.a : Symbol(a, Decl(objectSpreadUnion.ts, 1, 14), Decl(objectSpreadUnion.ts, 2, 14))
+>result : Symbol(result, Decl(objectSpreadUnion.ts, 4, 3))
+>a : Symbol(a, Decl(objectSpreadUnion.ts, 1, 14), Decl(objectSpreadUnion.ts, 2, 14))
+
+let assignable: { ...(A1 | A2) } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadUnion.ts, 6, 3))
+>A1 : Symbol(A1, Decl(objectSpreadUnion.ts, 0, 0))
+>A2 : Symbol(A2, Decl(objectSpreadUnion.ts, 1, 26))
+>result : Symbol(result, Decl(objectSpreadUnion.ts, 4, 3))
+
+function tripleUnion<T, U, V>(t: T, u: U, v: V): void {
+>tripleUnion : Symbol(tripleUnion, Decl(objectSpreadUnion.ts, 6, 42))
+>T : Symbol(T, Decl(objectSpreadUnion.ts, 8, 21))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 8, 23))
+>V : Symbol(V, Decl(objectSpreadUnion.ts, 8, 26))
+>t : Symbol(t, Decl(objectSpreadUnion.ts, 8, 30))
+>T : Symbol(T, Decl(objectSpreadUnion.ts, 8, 21))
+>u : Symbol(u, Decl(objectSpreadUnion.ts, 8, 35))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 8, 23))
+>v : Symbol(v, Decl(objectSpreadUnion.ts, 8, 41))
+>V : Symbol(V, Decl(objectSpreadUnion.ts, 8, 26))
+
+    let tuv: T | U | V;
+>tuv : Symbol(tuv, Decl(objectSpreadUnion.ts, 9, 7))
+>T : Symbol(T, Decl(objectSpreadUnion.ts, 8, 21))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 8, 23))
+>V : Symbol(V, Decl(objectSpreadUnion.ts, 8, 26))
+
+    let result = { id: 'foo', ...tuv };
+>result : Symbol(result, Decl(objectSpreadUnion.ts, 10, 7))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 10, 18))
+
+    let expected: { id: string, ...T } | { id: string, ...U } | { id: string, ...V } = result;
+>expected : Symbol(expected, Decl(objectSpreadUnion.ts, 11, 7))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 11, 19))
+>T : Symbol(T, Decl(objectSpreadUnion.ts, 8, 21))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 11, 42))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 8, 23))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 11, 65))
+>V : Symbol(V, Decl(objectSpreadUnion.ts, 8, 26))
+>result : Symbol(result, Decl(objectSpreadUnion.ts, 10, 7))
+
+    let assignable: { id: string, ...(T | U | V) } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadUnion.ts, 12, 7))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 12, 21))
+>T : Symbol(T, Decl(objectSpreadUnion.ts, 8, 21))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 8, 23))
+>V : Symbol(V, Decl(objectSpreadUnion.ts, 8, 26))
+>result : Symbol(result, Decl(objectSpreadUnion.ts, 10, 7))
+}
+function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
+>iteratedDoubleUnion : Symbol(iteratedDoubleUnion, Decl(objectSpreadUnion.ts, 13, 1))
+>T : Symbol(T, Decl(objectSpreadUnion.ts, 14, 29))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
+>V : Symbol(V, Decl(objectSpreadUnion.ts, 14, 34))
+>t : Symbol(t, Decl(objectSpreadUnion.ts, 14, 38))
+>T : Symbol(T, Decl(objectSpreadUnion.ts, 14, 29))
+>u : Symbol(u, Decl(objectSpreadUnion.ts, 14, 43))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
+>v : Symbol(v, Decl(objectSpreadUnion.ts, 14, 49))
+>V : Symbol(V, Decl(objectSpreadUnion.ts, 14, 34))
+
+    let tu: T | U;
+>tu : Symbol(tu, Decl(objectSpreadUnion.ts, 15, 7))
+>T : Symbol(T, Decl(objectSpreadUnion.ts, 14, 29))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
+
+    let uv: U | V;
+>uv : Symbol(uv, Decl(objectSpreadUnion.ts, 16, 7))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
+>V : Symbol(V, Decl(objectSpreadUnion.ts, 14, 34))
+
+    let result = { id: 'bar', ...tu, ...uv };
+>result : Symbol(result, Decl(objectSpreadUnion.ts, 17, 7))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 17, 18))
+
+    let expected: { id: string, ...T, ...U } | { id: string, ...T, ...V } | { id: string, ...U } | { id: string, ...U, ...V };
+>expected : Symbol(expected, Decl(objectSpreadUnion.ts, 18, 7))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 18, 19))
+>T : Symbol(T, Decl(objectSpreadUnion.ts, 14, 29))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 18, 48))
+>T : Symbol(T, Decl(objectSpreadUnion.ts, 14, 29))
+>V : Symbol(V, Decl(objectSpreadUnion.ts, 14, 34))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 18, 77))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 18, 100))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
+>V : Symbol(V, Decl(objectSpreadUnion.ts, 14, 34))
+
+    let assignable: { id: string, ...(T | U), ...(U | V) } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadUnion.ts, 19, 7))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 19, 21))
+>T : Symbol(T, Decl(objectSpreadUnion.ts, 14, 29))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
+>U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
+>V : Symbol(V, Decl(objectSpreadUnion.ts, 14, 34))
+>result : Symbol(result, Decl(objectSpreadUnion.ts, 17, 7))
+}
+
+
+
diff --git a/tests/baselines/reference/objectSpreadUnion.types b/tests/baselines/reference/objectSpreadUnion.types
new file mode 100644
index 0000000000000..7cbffcf0a584c
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadUnion.types
@@ -0,0 +1,131 @@
+=== tests/cases/conformance/types/spread/objectSpreadUnion.ts ===
+// concrete types work
+interface A1 { a: number }
+>A1 : A1
+>a : number
+
+interface A2 { a: string }
+>A2 : A2
+>a : string
+
+let a12: A1 | A2;
+>a12 : A1 | A2
+>A1 : A1
+>A2 : A2
+
+let result = { ...a12 };
+>result : { a: number; } | { a: string; }
+>{ ...a12 } : { a: number; } | { a: string; }
+>a12 : any
+
+let sn: number | string = result.a;
+>sn : string | number
+>result.a : string | number
+>result : { a: number; } | { a: string; }
+>a : string | number
+
+let assignable: { ...(A1 | A2) } = result;
+>assignable : { a: number; } | { a: string; }
+>A1 : A1
+>A2 : A2
+>result : { a: number; } | { a: string; }
+
+function tripleUnion<T, U, V>(t: T, u: U, v: V): void {
+>tripleUnion : <T, U, V>(t: T, u: U, v: V) => void
+>T : T
+>U : U
+>V : V
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+    let tuv: T | U | V;
+>tuv : T | U | V
+>T : T
+>U : U
+>V : V
+
+    let result = { id: 'foo', ...tuv };
+>result : { id: string; ...T } | { id: string; ...U } | { id: string; ...V }
+>{ id: 'foo', ...tuv } : { id: string; ...T } | { id: string; ...U } | { id: string; ...V }
+>id : string
+>'foo' : "foo"
+>tuv : any
+
+    let expected: { id: string, ...T } | { id: string, ...U } | { id: string, ...V } = result;
+>expected : { id: string; ...T } | { id: string; ...U } | { id: string; ...V }
+>id : string
+>T : T
+>id : string
+>U : U
+>id : string
+>V : V
+>result : { id: string; ...T } | { id: string; ...U } | { id: string; ...V }
+
+    let assignable: { id: string, ...(T | U | V) } = result;
+>assignable : { id: string; ...T } | { id: string; ...U } | { id: string; ...V }
+>id : string
+>T : T
+>U : U
+>V : V
+>result : { id: string; ...T } | { id: string; ...U } | { id: string; ...V }
+}
+function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
+>iteratedDoubleUnion : <T, U, V>(t: T, u: U, v: V) => void
+>T : T
+>U : U
+>V : V
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+    let tu: T | U;
+>tu : T | U
+>T : T
+>U : U
+
+    let uv: U | V;
+>uv : U | V
+>U : U
+>V : V
+
+    let result = { id: 'bar', ...tu, ...uv };
+>result : { id: string; ...T; ...U } | { id: string; ...U } | { id: string; ...T; ...V } | { id: string; ...U; ...V }
+>{ id: 'bar', ...tu, ...uv } : { id: string; ...T; ...U } | { id: string; ...U } | { id: string; ...T; ...V } | { id: string; ...U; ...V }
+>id : string
+>'bar' : "bar"
+>tu : any
+>uv : any
+
+    let expected: { id: string, ...T, ...U } | { id: string, ...T, ...V } | { id: string, ...U } | { id: string, ...U, ...V };
+>expected : { id: string; ...T; ...U } | { id: string; ...T; ...V } | { id: string; ...U } | { id: string; ...U; ...V }
+>id : string
+>T : T
+>U : U
+>id : string
+>T : T
+>V : V
+>id : string
+>U : U
+>id : string
+>U : U
+>V : V
+
+    let assignable: { id: string, ...(T | U), ...(U | V) } = result;
+>assignable : { id: string; ...T; ...U } | { id: string; ...U } | { id: string; ...T; ...V } | { id: string; ...U; ...V }
+>id : string
+>T : T
+>U : U
+>U : U
+>V : V
+>result : { id: string; ...T; ...U } | { id: string; ...U } | { id: string; ...T; ...V } | { id: string; ...U; ...V }
+}
+
+
+
diff --git a/tests/cases/conformance/types/spread/objectSpread.ts b/tests/cases/conformance/types/spread/objectSpread.ts
index 9828e86f0a6bc..e94775649e701 100644
--- a/tests/cases/conformance/types/spread/objectSpread.ts
+++ b/tests/cases/conformance/types/spread/objectSpread.ts
@@ -35,11 +35,13 @@ let getter: { a: number, c: number } =
     { ...op, c: 7 }
 getter.a = 12;
 
-// null and undefined are just skipped
-let spreadNull: { a: number } =
-    { a: 7, ...null }
-let spreadUndefined: { a: number } =
-    { a: 7, ...undefined }
+// null, undefined, functions and primitives result in { }
+let spreadNull = { ...null };
+let spreadUndefind = { ...undefined };
+let spreadNum = { ...12 };
+let spreadStr = { ...'foo' };
+let spreadBool = { ...false };
+let spreadFunc = { ...(function () { }) };
 
 // methods are not enumerable
 class C { p = 1; m() { } }
diff --git a/tests/cases/conformance/types/spread/objectSpreadIntersection.ts b/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
new file mode 100644
index 0000000000000..6471e622b68a4
--- /dev/null
+++ b/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
@@ -0,0 +1,36 @@
+function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
+    let tu: T | U;
+    let uv: U & V;
+    let result = { id: 'bar', ...tu, ...uv };
+    let expected: ({ id: string, ...T, ...U } & { id: string, ...T, ...V }) | ({ id: string, ...U } & { id: string, ...U, ...V });
+    let assignable: { id: string, ...(T | U), ...(U & V) } = result;
+}
+// concrete types work
+interface A1 { a: number }
+interface A2 { a: string }
+let a12: A1 & A2;
+let result = { ...a12 };
+let sn: number & string = result.a;
+let assignable: { ...(A1 & A2) } = result;
+
+function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
+    let tuv: T & U & V;
+    let result = { id: 'foo', ...tuv };
+    let expected: { id: string, ...T } & { id: string, ...U } & { id: string, ...V } = result;
+    let assignable: { id: string, ...(T & U & V) } = result;
+}
+function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
+    let tu: T & U;
+    let uv: U & V;
+    let result = { id: 'bar', ...tu, ...uv };
+    let expected: { id: string, ...T, ...U } & { id: string, ...T, ...V } & { id: string, ...U } & { id: string, ...U, ...V };
+    let assignable: { id: string, ...(T & U), ...(U & V) } = result;
+}
+function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
+    let tu: T & U;
+    let uv: U | V;
+    let result = { id: 'bar', ...tu, ...uv };
+    let expected: ({ id: string, ...T, ...U } & { id: string, ...U }) | ({ id: string, ...T, ...V } & { id: string, ...U, ...V });
+    let assignable: { id: string, ...(T & U), ...(U | V) } = result;
+}
+
diff --git a/tests/cases/conformance/types/spread/objectSpreadNegative.ts b/tests/cases/conformance/types/spread/objectSpreadNegative.ts
index d492db4c638b9..04a88d2a42738 100644
--- a/tests/cases/conformance/types/spread/objectSpreadNegative.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadNegative.ts
@@ -8,8 +8,8 @@ class PrivateOptionalX {
 class PublicX {
     public x: number;
 }
-let o3: { ...PublicX, ...PrivateOptionalX };
-let sn: number = o3.x; // error, x is private
+let o2: { ...PublicX, ...PrivateOptionalX };
+let sn: number = o2.x; // error, x is private
 let optionalString: { sn?: string };
 let optionalNumber: { sn?: number };
 let allOptional: { sn: string | number } = { ...optionalString, ...optionalNumber };
@@ -22,14 +22,29 @@ let spread: { ...Bool, ...Str } = { s: 'foo' }; // error, missing 'b'
 let b: Bool;
 spread = b; // error, missing 's'
 
-// expressions are not allowed
-let o1 = { ...1 + 1 };
-let o2 = { ...(1 + 1) };
-
 // literal repeats are not allowed, but spread repeats are fine
 let duplicated = { b: 'bad', ...o, b: 'bad', ...o2, b: 'bad' }
 let duplicatedSpread = { ...o, ...o }
 
+// null and undefined are just skipped
+let spreadNull = { ...null }
+spreadNull.null;
+let spreadUndefined = { ...undefined }
+spreadUndefined.undefined;
+
+// primitives and functions are skipped
+let spreadNum = { ...12 };
+spreadNum.toFixed(); // error, no methods from number
+let spreadSum = { ...1 + 1 };
+spreadSum.toFixed(); // error, no methods from number
+let spreadStr = { ...'foo' };
+spreadStr.length; // error, no 'length'
+spreadStr.charAt(1); // error, no methods either
+let spreadBool = { ...true };
+spreadBool.valueOf(); // error, what were you thinking?
+let spreadFunc = { ...function () { } }
+spreadFunc(); // error, no call signature
+
 // write-only properties get skipped
 let setterOnly = { ...{ set b (bad: number) { } } };
 setterOnly.b = 12; // error, 'b' does not exist
@@ -44,9 +59,6 @@ let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: numb
 callableConstructableSpread(12); // error, no call signature
 new callableConstructableSpread(12); // error, no construct signature
 
-let publicx: PublicX;
-let callableSpread = { ...publicx, ...(n => n + 1) }; // error, can't spread functions
-
 // { ...U } is not assignable to U
 function override<U>(initial: U, override: U): U {
     return { ...initial, ...override };
diff --git a/tests/cases/conformance/types/spread/objectSpreadUnion.ts b/tests/cases/conformance/types/spread/objectSpreadUnion.ts
new file mode 100644
index 0000000000000..03a4251ca8172
--- /dev/null
+++ b/tests/cases/conformance/types/spread/objectSpreadUnion.ts
@@ -0,0 +1,23 @@
+// concrete types work
+interface A1 { a: number }
+interface A2 { a: string }
+let a12: A1 | A2;
+let result = { ...a12 };
+let sn: number | string = result.a;
+let assignable: { ...(A1 | A2) } = result;
+
+function tripleUnion<T, U, V>(t: T, u: U, v: V): void {
+    let tuv: T | U | V;
+    let result = { id: 'foo', ...tuv };
+    let expected: { id: string, ...T } | { id: string, ...U } | { id: string, ...V } = result;
+    let assignable: { id: string, ...(T | U | V) } = result;
+}
+function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
+    let tu: T | U;
+    let uv: U | V;
+    let result = { id: 'bar', ...tu, ...uv };
+    let expected: { id: string, ...T, ...U } | { id: string, ...T, ...V } | { id: string, ...U } | { id: string, ...U, ...V };
+    let assignable: { id: string, ...(T | U), ...(U | V) } = result;
+}
+
+

From 2f77a54ea4196df86e3d215f3a1913bd9aede6c4 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Fri, 7 Oct 2016 09:29:11 -0700
Subject: [PATCH 032/224] Implicitly consider an extensionless file in
 "includes" to be a recursive directory glob

---
 src/compiler/commandLineParser.ts   |  28 ++--
 src/compiler/core.ts                | 173 ++++++++++++---------
 src/compiler/types.ts               |   1 +
 src/harness/unittests/matchFiles.ts | 228 +++++++++-------------------
 4 files changed, 197 insertions(+), 233 deletions(-)

diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 648447ac26ac4..135cec842e03c 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -984,9 +984,7 @@ namespace ts {
     function convertTypingOptionsFromJsonWorker(jsonOptions: any,
         basePath: string, errors: Diagnostic[], configFileName?: string): TypingOptions {
 
-        const options: TypingOptions = getBaseFileName(configFileName) === "jsconfig.json"
-            ? { enableAutoDiscovery: true, include: [], exclude: [] }
-            : { enableAutoDiscovery: false, include: [], exclude: [] };
+        const options: TypingOptions = { enableAutoDiscovery: getBaseFileName(configFileName) === "jsconfig.json", include: [], exclude: [] };
         convertOptionsFromJson(typingOptionDeclarations, jsonOptions, basePath, options, Diagnostics.Unknown_typing_option_0, errors);
         return options;
     }
@@ -1239,12 +1237,13 @@ namespace ts {
     /**
      * Gets directories in a set of include patterns that should be watched for changes.
      */
-    function getWildcardDirectories(include: string[], exclude: string[], path: string, useCaseSensitiveFileNames: boolean) {
+    function getWildcardDirectories(include: string[], exclude: string[], path: string, useCaseSensitiveFileNames: boolean): Map<WatchDirectoryFlags> {
         // We watch a directory recursively if it contains a wildcard anywhere in a directory segment
         // of the pattern:
         //
         //  /a/b/**/d   - Watch /a/b recursively to catch changes to any d in any subfolder recursively
         //  /a/b/*/d    - Watch /a/b recursively to catch any d in any immediate subfolder, even if a new subfolder is added
+        //  /a/b        - Watch /a/b recursively to catch changes to anything in any recursive subfoler
         //
         // We watch a directory without recursion if it contains a wildcard in the file segment of
         // the pattern:
@@ -1257,15 +1256,14 @@ namespace ts {
         if (include !== undefined) {
             const recursiveKeys: string[] = [];
             for (const file of include) {
-                const name = normalizePath(combinePaths(path, file));
-                if (excludeRegex && excludeRegex.test(name)) {
+                const spec = normalizePath(combinePaths(path, file));
+                if (excludeRegex && excludeRegex.test(spec)) {
                     continue;
                 }
 
-                const match = wildcardDirectoryPattern.exec(name);
+                const match = getWildcardDirectoryFromSpec(spec, useCaseSensitiveFileNames);
                 if (match) {
-                    const key = useCaseSensitiveFileNames ? match[0] : match[0].toLowerCase();
-                    const flags = watchRecursivePattern.test(name) ? WatchDirectoryFlags.Recursive : WatchDirectoryFlags.None;
+                    const { key, flags } = match;
                     const existingFlags = wildcardDirectories[key];
                     if (existingFlags === undefined || existingFlags < flags) {
                         wildcardDirectories[key] = flags;
@@ -1289,6 +1287,18 @@ namespace ts {
         return wildcardDirectories;
     }
 
+    function getWildcardDirectoryFromSpec(spec: string, useCaseSensitiveFileNames: boolean): { key: string, flags: WatchDirectoryFlags } | undefined {
+        const match = wildcardDirectoryPattern.exec(spec);
+        return match
+            ? {
+                key: useCaseSensitiveFileNames ? match[0] : match[0].toLowerCase(),
+                flags: watchRecursivePattern.test(spec) ? WatchDirectoryFlags.Recursive : WatchDirectoryFlags.None
+            }
+            : isImplicitGlob(spec)
+            ? { key: spec, flags: WatchDirectoryFlags.Recursive }
+            : undefined;
+    }
+
     /**
      * Determines whether a literal or wildcard file has already been included that has a higher
      * extension priority.
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 7c68306211a78..81662af91cf83 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -1177,7 +1177,7 @@ namespace ts {
 
     /**
      * Returns the path except for its basename. Eg:
-     * 
+     *
      * /path/to/file.ext -> /path/to
      */
     export function getDirectoryPath(path: Path): Path;
@@ -1186,6 +1186,12 @@ namespace ts {
         return path.substr(0, Math.max(getRootLength(path), path.lastIndexOf(directorySeparator)));
     }
 
+    function getBasename(path: Path): Path;
+    function getBasename(path: string): string;
+    function getBasename(path: string): any {
+        return path.substr(Math.max(getRootLength(path), path.lastIndexOf(directorySeparator)));
+    }
+
     export function isUrl(path: string) {
         return path && !isRootedDiskPath(path) && path.indexOf("://") !== -1;
     }
@@ -1476,7 +1482,7 @@ namespace ts {
             return undefined;
         }
 
-        const replaceWildcardCharacter =  usage === "files" ? replaceWildCardCharacterFiles : replaceWildCardCharacterOther;
+        const replaceWildcardCharacter = usage === "files" ? replaceWildCardCharacterFiles : replaceWildCardCharacterOther;
         const singleAsteriskRegexFragment = usage === "files" ? singleAsteriskRegexFragmentFiles : singleAsteriskRegexFragmentOther;
 
         /**
@@ -1487,81 +1493,103 @@ namespace ts {
 
         let pattern = "";
         let hasWrittenSubpattern = false;
-        spec: for (const spec of specs) {
+        for (const spec of specs) {
             if (!spec) {
                 continue;
             }
 
-            let subpattern = "";
-            let hasRecursiveDirectoryWildcard = false;
-            let hasWrittenComponent = false;
-            const components = getNormalizedPathComponents(spec, basePath);
-            if (usage !== "exclude" && components[components.length - 1] === "**") {
-                continue spec;
+            const subPattern = getSubPatternFromSpec(spec, basePath, usage, singleAsteriskRegexFragment, doubleAsteriskRegexFragment, replaceWildcardCharacter);
+            if (subPattern === undefined) {
+                continue;
             }
 
-            // getNormalizedPathComponents includes the separator for the root component.
-            // We need to remove to create our regex correctly.
-            components[0] = removeTrailingDirectorySeparator(components[0]);
+            if (hasWrittenSubpattern) {
+                pattern += "|";
+            }
 
-            let optionalCount = 0;
-            for (let component of components) {
-                if (component === "**") {
-                    if (hasRecursiveDirectoryWildcard) {
-                        continue spec;
-                    }
+            pattern += "(" + subPattern + ")";
+            hasWrittenSubpattern = true;
+        }
 
-                    subpattern += doubleAsteriskRegexFragment;
-                    hasRecursiveDirectoryWildcard = true;
-                    hasWrittenComponent = true;
-                }
-                else {
-                    if (usage === "directories") {
-                        subpattern += "(";
-                        optionalCount++;
-                    }
+        if (!pattern) {
+            return undefined;
+        }
 
-                    if (hasWrittenComponent) {
-                        subpattern += directorySeparator;
-                    }
+        return "^(" + pattern + (usage === "exclude" ? ")($|/)" : ")$");
+    }
 
-                    if (usage !== "exclude") {
-                        // The * and ? wildcards should not match directories or files that start with . if they
-                        // appear first in a component. Dotted directories and files can be included explicitly
-                        // like so: **/.*/.*
-                        if (component.charCodeAt(0) === CharacterCodes.asterisk) {
-                            subpattern += "([^./]" + singleAsteriskRegexFragment + ")?";
-                            component = component.substr(1);
-                        }
-                        else if (component.charCodeAt(0) === CharacterCodes.question) {
-                            subpattern += "[^./]";
-                            component = component.substr(1);
-                        }
-                    }
+    /**
+     * An "includes" path "foo" is implicitly a glob "foo\**\*" (replace \ with /) if its last component has no extension,
+     * and does not contain any glob characters itself.
+     */
+    export function isImplicitGlob(lastPathComponent: string): boolean {
+        return !/[.*?]/.test(lastPathComponent);
+    }
+
+    function getSubPatternFromSpec(spec: string, basePath: string, usage: "files" | "directories" | "exclude", singleAsteriskRegexFragment: string, doubleAsteriskRegexFragment: string, replaceWildcardCharacter: (match: string) => string): string | undefined {
+        let subpattern = "";
+        let hasRecursiveDirectoryWildcard = false;
+        let hasWrittenComponent = false;
+        const components = getNormalizedPathComponents(spec, basePath);
+        const lastComponent = lastOrUndefined(components);
+        if (usage !== "exclude" && lastComponent === "**") {
+            return undefined;
+        }
+
+        // getNormalizedPathComponents includes the separator for the root component.
+        // We need to remove to create our regex correctly.
+        components[0] = removeTrailingDirectorySeparator(components[0]);
 
-                    subpattern += component.replace(reservedCharacterPattern, replaceWildcardCharacter);
-                    hasWrittenComponent = true;
+        if (isImplicitGlob(lastComponent)) {
+            components.push("**", "*");
+        }
+
+        let optionalCount = 0;
+        for (let component of components) {
+            if (component === "**") {
+                if (hasRecursiveDirectoryWildcard) {
+                    return undefined;
                 }
-            }
 
-            while (optionalCount > 0) {
-                subpattern += ")?";
-                optionalCount--;
+                subpattern += doubleAsteriskRegexFragment;
+                hasRecursiveDirectoryWildcard = true;
             }
+            else {
+                if (usage === "directories") {
+                    subpattern += "(";
+                    optionalCount++;
+                }
 
-            if (hasWrittenSubpattern) {
-                pattern += "|";
+                if (hasWrittenComponent) {
+                    subpattern += directorySeparator;
+                }
+
+                if (usage !== "exclude") {
+                    // The * and ? wildcards should not match directories or files that start with . if they
+                    // appear first in a component. Dotted directories and files can be included explicitly
+                    // like so: **/.*/.*
+                    if (component.charCodeAt(0) === CharacterCodes.asterisk) {
+                        subpattern += "([^./]" + singleAsteriskRegexFragment + ")?";
+                        component = component.substr(1);
+                    }
+                    else if (component.charCodeAt(0) === CharacterCodes.question) {
+                        subpattern += "[^./]";
+                        component = component.substr(1);
+                    }
+                }
+
+                subpattern += component.replace(reservedCharacterPattern, replaceWildcardCharacter);
             }
 
-            pattern += "(" + subpattern + ")";
-            hasWrittenSubpattern = true;
+            hasWrittenComponent = true;
         }
 
-        if (!pattern) {
-            return undefined;
+        while (optionalCount > 0) {
+            subpattern += ")?";
+            optionalCount--;
         }
 
-        return "^(" + pattern + (usage === "exclude" ? ")($|/)" : ")$");
+        return subpattern;
     }
 
     function replaceWildCardCharacterFiles(match: string) {
@@ -1648,6 +1676,7 @@ namespace ts {
     function getBasePaths(path: string, includes: string[], useCaseSensitiveFileNames: boolean) {
         // Storage for our results in the form of literal paths (e.g. the paths as written by the user).
         const basePaths: string[] = [path];
+
         if (includes) {
             // Storage for literal base paths amongst the include patterns.
             const includeBasePaths: string[] = [];
@@ -1655,14 +1684,8 @@ namespace ts {
                 // We also need to check the relative paths by converting them to absolute and normalizing
                 // in case they escape the base path (e.g "..\somedirectory")
                 const absolute: string = isRootedDiskPath(include) ? include : normalizePath(combinePaths(path, include));
-
-                const wildcardOffset = indexOfAnyCharCode(absolute, wildcardCharCodes);
-                const includeBasePath = wildcardOffset < 0
-                    ? removeTrailingDirectorySeparator(getDirectoryPath(absolute))
-                    : absolute.substring(0, absolute.lastIndexOf(directorySeparator, wildcardOffset));
-
                 // Append the literal and canonical candidate base paths.
-                includeBasePaths.push(includeBasePath);
+                includeBasePaths.push(getIncludeBasePath(absolute));
             }
 
             // Sort the offsets array using either the literal or canonical path representations.
@@ -1670,21 +1693,29 @@ namespace ts {
 
             // Iterate over each include base path and include unique base paths that are not a
             // subpath of an existing base path
-            include: for (let i = 0; i < includeBasePaths.length; i++) {
-                const includeBasePath = includeBasePaths[i];
-                for (let j = 0; j < basePaths.length; j++) {
-                    if (containsPath(basePaths[j], includeBasePath, path, !useCaseSensitiveFileNames)) {
-                        continue include;
-                    }
+            for (const includeBasePath of includeBasePaths) {
+                if (ts.every(basePaths, basePath => !containsPath(basePath, includeBasePath, path, !useCaseSensitiveFileNames))) {
+                    basePaths.push(includeBasePath);
                 }
-
-                basePaths.push(includeBasePath);
             }
         }
 
         return basePaths;
     }
 
+    function getIncludeBasePath(absolute: string): string {
+        const wildcardOffset = indexOfAnyCharCode(absolute, wildcardCharCodes);
+        if (wildcardOffset < 0) {
+            // No "*" in the path
+            return isImplicitGlob(getBasename(absolute))
+                ? absolute
+                : removeTrailingDirectorySeparator(getDirectoryPath(absolute));
+        }
+        else {
+            return absolute.substring(0, absolute.lastIndexOf(directorySeparator, wildcardOffset));
+        }
+    }
+
     export function ensureScriptKind(fileName: string, scriptKind?: ScriptKind): ScriptKind {
         // Using scriptKind as a condition handles both:
         // - 'scriptKind' is unspecified and thus it is `undefined`
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 638504e613f11..cb64fdbc61a29 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -3073,6 +3073,7 @@ namespace ts {
         Pretty,
     }
 
+    /** Either a parsed command line or a parsed tsconfig.json */
     export interface ParsedCommandLine {
         options: CompilerOptions;
         typingOptions?: TypingOptions;
diff --git a/src/harness/unittests/matchFiles.ts b/src/harness/unittests/matchFiles.ts
index 6b499e5698909..115d822c9b8bd 100644
--- a/src/harness/unittests/matchFiles.ts
+++ b/src/harness/unittests/matchFiles.ts
@@ -88,6 +88,12 @@ namespace ts {
         "c:/dev/g.min.js/.g/g.ts"
     ]);
 
+    function assertParsed(actual: ts.ParsedCommandLine, expected: ts.ParsedCommandLine): void {
+        assert.deepEqual(actual.fileNames, expected.fileNames);
+        assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
+        assert.deepEqual(actual.errors, expected.errors);
+    }
+
     describe("matchFiles", () => {
         describe("with literal file list", () => {
             it("without exclusions", () => {
@@ -107,9 +113,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("missing files are still present", () => {
                 const json = {
@@ -128,9 +132,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("are not removed due to excludes", () => {
                 const json = {
@@ -152,9 +154,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
         });
 
@@ -176,9 +176,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with non .ts file extensions are excluded", () => {
                 const json = {
@@ -194,9 +192,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with missing files are excluded", () => {
                 const json = {
@@ -212,9 +208,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with literal excludes", () => {
                 const json = {
@@ -235,9 +229,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with wildcard excludes", () => {
                 const json = {
@@ -265,9 +257,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with recursive excludes", () => {
                 const json = {
@@ -294,9 +284,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with case sensitive exclude", () => {
                 const json = {
@@ -316,9 +304,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseSensitiveHost, caseSensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with common package folders and no exclusions", () => {
                 const json = {
@@ -340,9 +326,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveCommonFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with common package folders and exclusions", () => {
                 const json = {
@@ -369,9 +353,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveCommonFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with common package folders and empty exclude", () => {
                 const json = {
@@ -397,9 +379,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveCommonFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
         });
 
@@ -423,9 +403,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("`*` matches only ts files", () => {
                 const json = {
@@ -446,9 +424,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("`?` matches only a single character", () => {
                 const json = {
@@ -468,9 +444,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with recursive directory", () => {
                 const json = {
@@ -492,9 +466,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with multiple recursive directories", () => {
                 const json = {
@@ -518,9 +490,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("case sensitive", () => {
                 const json = {
@@ -539,9 +509,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseSensitiveHost, caseSensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with missing files are excluded", () => {
                 const json = {
@@ -558,9 +526,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("always include literal files", () => {
                 const json = {
@@ -585,9 +551,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("exclude folders", () => {
                 const json = {
@@ -612,9 +576,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with common package folders and no exclusions", () => {
                 const json = {
@@ -633,9 +595,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveCommonFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with common package folders and exclusions", () => {
                 const json = {
@@ -659,9 +619,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveCommonFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with common package folders and empty exclude", () => {
                 const json = {
@@ -684,9 +642,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveCommonFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("exclude .js files when allowJs=false", () => {
                 const json = {
@@ -708,9 +664,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("include .js files when allowJs=true", () => {
                 const json = {
@@ -735,9 +689,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("include explicitly listed .min.js files when allowJs=true", () => {
                 const json = {
@@ -762,9 +714,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("include paths outside of the project", () => {
                 const json = {
@@ -788,9 +738,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("include paths outside of the project using relative paths", () => {
                 const json = {
@@ -813,9 +761,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("exclude paths outside of the project using relative paths", () => {
                 const json = {
@@ -833,9 +779,7 @@ namespace ts {
                     wildcardDirectories: {}
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("include files with .. in their name", () => {
                 const json = {
@@ -855,9 +799,7 @@ namespace ts {
                     wildcardDirectories: {}
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("exclude files with .. in their name", () => {
                 const json = {
@@ -879,9 +821,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with jsx=none, allowJs=false", () => {
                 const json = {
@@ -904,9 +844,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveMixedExtensionHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with jsx=preserve, allowJs=false", () => {
                 const json = {
@@ -931,9 +869,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveMixedExtensionHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with jsx=none, allowJs=true", () => {
                 const json = {
@@ -958,9 +894,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveMixedExtensionHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with jsx=preserve, allowJs=true", () => {
                 const json = {
@@ -987,9 +921,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveMixedExtensionHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("exclude .min.js files using wildcards", () => {
                 const json = {
@@ -1016,9 +948,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             describe("with trailing recursive directory", () => {
                 it("in includes", () => {
@@ -1036,9 +966,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
                 it("in excludes", () => {
                     const json = {
@@ -1056,9 +984,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
             });
             describe("with multiple recursive directory patterns", () => {
@@ -1077,9 +1003,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
                 it("in excludes", () => {
                     const json = {
@@ -1106,9 +1030,7 @@ namespace ts {
                         }
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
             });
 
@@ -1128,9 +1050,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
 
                 it("in includes after a subdirectory", () => {
@@ -1148,9 +1068,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
 
                 it("in excludes immediately after", () => {
@@ -1178,9 +1096,7 @@ namespace ts {
                         }
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
 
                 it("in excludes after a subdirectory", () => {
@@ -1208,9 +1124,25 @@ namespace ts {
                         }
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
+                });
+            });
+
+            describe("with implicit globbification", () => {
+                it("Expands 'z' to 'z/**/*'", () => {
+                    const json = {
+                        include: ["z"]
+                    };
+                    const expected: ts.ParsedCommandLine = {
+                        options: {},
+                        errors: [],
+                        fileNames: [ "a.ts", "aba.ts", "abz.ts", "b.ts", "bba.ts", "bbz.ts" ].map(x => `c:/dev/z/${x}`),
+                        wildcardDirectories: {
+                            "c:/dev/z": ts.WatchDirectoryFlags.Recursive
+                        }
+                    };
+                    const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
+                    assertParsed(actual, expected);
                 });
             });
         });
@@ -1235,9 +1167,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveDottedFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             describe("that are explicitly included", () => {
                 it("without wildcards", () => {
@@ -1257,9 +1187,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveDottedFoldersHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
                 it("with recursive wildcards that match directories", () => {
                     const json = {
@@ -1281,9 +1209,7 @@ namespace ts {
                         }
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveDottedFoldersHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
                 it("with recursive wildcards that match nothing", () => {
                     const json = {
@@ -1305,9 +1231,7 @@ namespace ts {
                         }
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveDottedFoldersHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
                 it("with wildcard excludes that implicitly exclude dotted files", () => {
                     const json = {
@@ -1325,9 +1249,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveDottedFoldersHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
             });
         });

From 14701e3067a94a8ebc299a498581469f63025c96 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Tue, 11 Oct 2016 13:44:20 -0700
Subject: [PATCH 033/224] Respond to some PR comments

---
 src/compiler/binder.ts      |  2 +-
 src/compiler/checker.ts     | 10 +++++-----
 src/compiler/collections.ts | 32 +++++++++++++-------------------
 src/compiler/program.ts     |  2 +-
 src/harness/harness.ts      |  6 ++++--
 5 files changed, 24 insertions(+), 28 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index bb7166beeec24..efc1e53efb8c5 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -1460,7 +1460,7 @@ namespace ts {
 
             const typeLiteralSymbol = createSymbol(SymbolFlags.TypeLiteral, "__type");
             addDeclarationToSymbol(typeLiteralSymbol, node, SymbolFlags.TypeLiteral);
-            typeLiteralSymbol.members = createMapWithEntry(symbol.name, symbol);
+            typeLiteralSymbol.members = new StringMap([[symbol.name, symbol]]);
         }
 
         function bindObjectLiteralExpression(node: ObjectLiteralExpression) {
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 514d225139e84..a01c3d9f975ec 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -352,7 +352,7 @@ namespace ts {
             ResolvedReturnType
         }
 
-        const builtinGlobals = createMapWithEntry(undefinedSymbol.name, undefinedSymbol);
+        const builtinGlobals = new StringMap([[undefinedSymbol.name, undefinedSymbol]]);
 
         initializeTypeChecker();
 
@@ -3789,7 +3789,7 @@ namespace ts {
                     type.typeParameters = concatenate(outerTypeParameters, localTypeParameters);
                     type.outerTypeParameters = outerTypeParameters;
                     type.localTypeParameters = localTypeParameters;
-                    (<GenericType>type).instantiations = createMapWithEntry(getTypeListId(type.typeParameters), <GenericType>type);
+                    (<GenericType>type).instantiations = new StringMap([[getTypeListId(type.typeParameters), <GenericType>type]]);
                     (<GenericType>type).target = <GenericType>type;
                     (<GenericType>type).typeArguments = type.typeParameters;
                     type.thisType = <TypeParameter>createType(TypeFlags.TypeParameter);
@@ -3831,7 +3831,7 @@ namespace ts {
                     if (typeParameters) {
                         // Initialize the instantiation cache for generic type aliases. The declared type corresponds to
                         // an instantiation of the type alias with the type parameters supplied as type arguments.
-                        links.instantiations = createMapWithEntry(getTypeListId(links.typeParameters), type);
+                        links.instantiations = new StringMap([[getTypeListId(links.typeParameters), type]]);
                     }
                 }
                 else {
@@ -5343,7 +5343,7 @@ namespace ts {
             type.typeParameters = typeParameters;
             type.outerTypeParameters = undefined;
             type.localTypeParameters = typeParameters;
-            type.instantiations = createMapWithEntry(getTypeListId(type.typeParameters), <GenericType>type);
+            type.instantiations = new StringMap([[getTypeListId(type.typeParameters), <GenericType>type]]);
             type.target = <GenericType>type;
             type.typeArguments = type.typeParameters;
             type.thisType = <TypeParameter>createType(TypeFlags.TypeParameter);
@@ -6831,7 +6831,7 @@ namespace ts {
                 }
                 sourceStack[depth] = source;
                 targetStack[depth] = target;
-                maybeStack[depth] = createMapWithEntry(id, RelationComparisonResult.Succeeded);
+                maybeStack[depth] = new StringMap([[id, RelationComparisonResult.Succeeded]]);
                 depth++;
                 const saveExpandingFlags = expandingFlags;
                 if (!(expandingFlags & 1) && isDeeplyNestedGeneric(source, sourceStack, depth)) expandingFlags |= 1;
diff --git a/src/compiler/collections.ts b/src/compiler/collections.ts
index e553363e380e6..40ae40bad0598 100644
--- a/src/compiler/collections.ts
+++ b/src/compiler/collections.ts
@@ -71,13 +71,19 @@ namespace ts {
     };
 
     export interface StringMapConstructor {
-        new<T>(): Map<string, T>;
+        new<T>(pairs?: [string, T][]): Map<string, T>;
     }
     /** In runtimes without Maps, this is implemented using an object. */
     export const StringMap: StringMapConstructor = usingNativeMaps ? Map : class ShimStringMap<T> implements Map<string, T> {
         private data = createDictionaryModeObject<T>();
 
-        constructor() {}
+        constructor(pairs?: [string, T][]) {
+            if (pairs) {
+                for (const [key, value] of pairs) {
+                    this.data[key] = value;
+                }
+            }
+        }
 
         clear() {
             this.data = createDictionaryModeObject<T>();
@@ -276,16 +282,8 @@ namespace ts {
     export const setIsEmpty: (set: Set<string>) => boolean = usingNativeSets
         ? set => (set as any).size === 0
         : (set: ShimStringSet) => set.isEmpty();
-}
 
-// Map utilities
-namespace ts {
-    /** Create a map containing a single entry key -> value. */
-    export function createMapWithEntry<T>(key: string, value: T): Map<string, T> {
-        const map = new StringMap<T>();
-        map.set(key, value);
-        return map;
-    }
+    // Map utilities
 
     /** Set a value in a map, then return that value. */
     export function setAndReturn<K, V>(map: Map<K, V>, key: K, value: V): V {
@@ -477,11 +475,9 @@ namespace ts {
         naturalNumberKeys.sort((a, b) => toInt(a) - toInt(b));
         return naturalNumberKeys.concat(allOtherKeys);
     }
-}
 
-// Set utilities
-/* @internal */
-namespace ts {
+    // Set utilities
+
     /** Union of the `getSet` of each element in the array. */
     export function setAggregate<T>(array: T[], getSet: (t: T) => Set<string>): Set<string> {
         const result = new StringSet();
@@ -506,11 +502,9 @@ namespace ts {
         });
         return result;
     }
-}
 
-// MapLike utilities
-/* @internal */
-namespace ts {
+    // MapLike utilities
+
     const hasOwnProperty = Object.prototype.hasOwnProperty;
 
     export function clone<T>(object: T): T {
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index cdadbe2a259ff..ff58f2ca4bba7 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -146,7 +146,7 @@ namespace ts {
                 const fingerprint = outputFingerprints.get(fileName);
 
                 // If output has not been changed, and the file has no external modification
-                if (fingerprint !== undefined && fingerprint.byteOrderMark === writeByteOrderMark &&
+                if (fingerprint && fingerprint.byteOrderMark === writeByteOrderMark &&
                     fingerprint.hash === hash &&
                     fingerprint.mtime.getTime() === mtimeBefore.getTime()) {
                     return;
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index ab7133b94a454..889dd6738b3f8 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -925,8 +925,10 @@ namespace Harness {
         export const defaultLibFileName = "lib.d.ts";
         export const es2015DefaultLibFileName = "lib.es2015.d.ts";
 
-        const libFileNameSourceFileMap = ts.createMapWithEntry<ts.SourceFile>(defaultLibFileName,
-            createSourceFileAndAssertInvariants(defaultLibFileName, IO.readFile(libFolder + "lib.es5.d.ts"), /*languageVersion*/ ts.ScriptTarget.Latest));
+        const libFileNameSourceFileMap = new ts.StringMap<ts.SourceFile>([[
+            defaultLibFileName,
+            createSourceFileAndAssertInvariants(defaultLibFileName, IO.readFile(libFolder + "lib.es5.d.ts"), /*languageVersion*/ ts.ScriptTarget.Latest)
+        ]]);
 
         export function getDefaultLibrarySourceFile(fileName = defaultLibFileName): ts.SourceFile {
             if (!isDefaultLibraryFile(fileName)) {

From 1b3b35f3e0be5c880c01b262f6731659dc4725dd Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 11 Oct 2016 16:12:57 -0700
Subject: [PATCH 034/224] Type inference for spread types

Also:
1. Fix missing spread index signatures in getTypeFromTypeLiteral
2. Spread adjacent object types during spread type creation.
---
 src/compiler/checker.ts | 129 ++++++++++++++++++++++++++++++----------
 1 file changed, 99 insertions(+), 30 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 9d8ea29a3819b..93d9c19a71bc7 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5715,19 +5715,37 @@ namespace ts {
                 let type: ObjectType;
                 if (isSpread) {
                     let members: Map<Symbol>;
+                    let stringIndexInfo: IndexInfo;
+                    let numberIndexInfo: IndexInfo;
                     const spreads: Type[] = [];
                     for (const member of (node as TypeLiteralNode).members) {
                         if (member.kind === SyntaxKind.SpreadTypeElement) {
                             if (members) {
-                                spreads.push(createAnonymousType(node.symbol, members, emptyArray, emptyArray, undefined, undefined));
+                                spreads.push(createAnonymousType(node.symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo));
                                 members = undefined;
+                                stringIndexInfo = undefined;
+                                numberIndexInfo = undefined;
                             }
                             spreads.push(getTypeFromTypeNode((member as SpreadTypeElement).type));
                         }
-                        else if (member.kind !== SyntaxKind.CallSignature &&
-                                 member.kind !== SyntaxKind.ConstructSignature &&
-                                 member.kind !== SyntaxKind.IndexSignature) {
-                            // note that spread types don't include call and construct signatures, and index signatures are resolved later
+                        else if (member.kind === SyntaxKind.IndexSignature) {
+                            const index = member as IndexSignatureDeclaration;
+                            if (index.parameters.length === 1) {
+                                const parameter = index.parameters[0];
+                                if (parameter && parameter.type) {
+                                    const indexInfo = createIndexInfo(index.type ? getTypeFromTypeNode(index.type) : anyType,
+                                                                      (getModifierFlags(index) & ModifierFlags.Readonly) !== 0, index);
+                                    if (parameter.type.kind === SyntaxKind.StringKeyword) {
+                                        stringIndexInfo = indexInfo;
+                                    }
+                                    else {
+                                        numberIndexInfo = indexInfo;
+                                    }
+                                }
+                            }
+                        }
+                        else if (member.kind !== SyntaxKind.CallSignature && member.kind !== SyntaxKind.ConstructSignature) {
+                            // note that spread types don't include call and construct signatures
                             const flags = SymbolFlags.Property | SymbolFlags.Transient | (member.questionToken ? SymbolFlags.Optional : 0);
                             const text = getTextOfPropertyName(member.name);
                             const symbol = <TransientSymbol>createSymbol(flags, text);
@@ -5740,8 +5758,8 @@ namespace ts {
                             members[symbol.name] = symbol;
                         }
                     }
-                    if (members) {
-                        spreads.push(createAnonymousType(node.symbol, members, emptyArray, emptyArray, undefined, undefined));
+                    if (members || stringIndexInfo || numberIndexInfo) {
+                        spreads.push(createAnonymousType(node.symbol, members || emptySymbols, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo));
                     }
                     return getSpreadType(spreads, node.symbol, aliasSymbol, aliasTypeArguments);
                 }
@@ -5802,6 +5820,15 @@ namespace ts {
                 // for types like T ... T, just return ... T
                 return left;
             }
+
+            if (right.flags & TypeFlags.ObjectType &&
+                left.flags & TypeFlags.Spread &&
+                (left as SpreadType).right.flags & TypeFlags.ObjectType) {
+                // simplify two adjacent object types: T ... { x } ... { y } becomes T ... { x, y }
+                // Note: left.left is always a spread type. Can we use this fact to avoid calling getSpreadType again?
+                return getSpreadType([getSpreadType([right, (left as SpreadType).right], symbol, aliasSymbol, aliasTypeArguments),
+                                      (left as SpreadType).left], symbol, aliasSymbol, aliasTypeArguments);
+            }
             if (left.flags & TypeFlags.Intersection) {
                 const spreads = map((left as IntersectionType).types,
                                   t => getSpreadType(types.slice().concat([t, right]), symbol, aliasSymbol, aliasTypeArguments));
@@ -7991,7 +8018,8 @@ namespace ts {
             return !!(type.flags & TypeFlags.TypeParameter ||
                 type.flags & TypeFlags.Reference && forEach((<TypeReference>type).typeArguments, couldContainTypeParameters) ||
                 type.flags & TypeFlags.Anonymous && type.symbol && type.symbol.flags & (SymbolFlags.Method | SymbolFlags.TypeLiteral | SymbolFlags.Class) ||
-                type.flags & TypeFlags.UnionOrIntersection && couldUnionOrIntersectionContainTypeParameters(<UnionOrIntersectionType>type));
+                type.flags & TypeFlags.UnionOrIntersection && couldUnionOrIntersectionContainTypeParameters(<UnionOrIntersectionType>type) ||
+                type.flags & TypeFlags.Spread && couldSpreadContainTypeParameters(type as SpreadType));
         }
 
         function couldUnionOrIntersectionContainTypeParameters(type: UnionOrIntersectionType): boolean {
@@ -8001,6 +8029,11 @@ namespace ts {
             return type.couldContainTypeParameters;
         }
 
+        function couldSpreadContainTypeParameters(type: SpreadType): boolean {
+            return !!(type.right.flags & TypeFlags.TypeParameter ||
+                      type.left.flags & TypeFlags.Spread && (type.left as SpreadType).right.flags & TypeFlags.TypeParameter);
+        }
+
         function isTypeParameterAtTopLevel(type: Type, typeParameter: TypeParameter): boolean {
             return type === typeParameter || type.flags & TypeFlags.UnionOrIntersection && forEach((<UnionOrIntersectionType>type).types, t => isTypeParameterAtTopLevel(t, typeParameter));
         }
@@ -8064,6 +8097,16 @@ namespace ts {
                         target = removeTypesFromUnionOrIntersection(<UnionOrIntersectionType>target, matchingTypes);
                     }
                 }
+                if (source.flags & TypeFlags.Spread && target.flags & TypeFlags.Spread) {
+                    // only the last type parameter is a valid inference site,
+                    // and only if not followed by object literal properties.
+                    if((source as SpreadType).right.flags & TypeFlags.TypeParameter &&
+                       (target as SpreadType).right.flags & TypeFlags.TypeParameter) {
+                        inferFromTypes((source as SpreadType).right, (target as SpreadType).right);
+                    }
+
+                    return;
+                }
                 if (target.flags & TypeFlags.TypeParameter) {
                     // If target is a type parameter, make an inference, unless the source type contains
                     // the anyFunctionType (the wildcard type that's used to avoid contextually typing functions).
@@ -8140,31 +8183,57 @@ namespace ts {
                 else {
                     source = getApparentType(source);
                     if (source.flags & TypeFlags.ObjectType) {
-                        if (isInProcess(source, target)) {
-                            return;
-                        }
-                        if (isDeeplyNestedGeneric(source, sourceStack, depth) && isDeeplyNestedGeneric(target, targetStack, depth)) {
-                            return;
-                        }
-                        const key = source.id + "," + target.id;
-                        if (visited[key]) {
-                            return;
+                        if (target.flags & TypeFlags.Spread) {
+                            // with an object type as source, a spread target infers to its last type parameter it
+                            // contains, after removing any properties from a object type that precedes the type parameter
+                            // Note that the call to `typeDifference` creates a new anonymous type.
+                            const spread = target as SpreadType;
+                            const parameter = spread.right.flags & TypeFlags.TypeParameter ? spread.right : (spread.left as SpreadType).right;
+                            const object = spread.right.flags & TypeFlags.TypeParameter ? emptyObjectType : spread.right as ResolvedType;
+                            inferFromTypes(getTypeDifference(source, object), parameter);
+                            target = object;
                         }
-                        visited[key] = true;
-                        if (depth === 0) {
-                            sourceStack = [];
-                            targetStack = [];
-                        }
-                        sourceStack[depth] = source;
-                        targetStack[depth] = target;
-                        depth++;
-                        inferFromProperties(source, target);
-                        inferFromSignatures(source, target, SignatureKind.Call);
-                        inferFromSignatures(source, target, SignatureKind.Construct);
-                        inferFromIndexTypes(source, target);
-                        depth--;
+                        inferFromStructure(source, target);
+                    }
+                }
+            }
+
+            function inferFromStructure(source: Type, target: Type) {
+                if (isInProcess(source, target)) {
+                    return;
+                }
+                if (isDeeplyNestedGeneric(source, sourceStack, depth) && isDeeplyNestedGeneric(target, targetStack, depth)) {
+                    return;
+                }
+                const key = source.id + "," + target.id;
+                if (visited[key]) {
+                    return;
+                }
+                visited[key] = true;
+                if (depth === 0) {
+                    sourceStack = [];
+                    targetStack = [];
+                }
+                sourceStack[depth] = source;
+                targetStack[depth] = target;
+                depth++;
+                inferFromProperties(source, target);
+                inferFromSignatures(source, target, SignatureKind.Call);
+                inferFromSignatures(source, target, SignatureKind.Construct);
+                inferFromIndexTypes(source, target);
+                depth--;
+            }
+
+            function getTypeDifference(type: ObjectType, diff: ResolvedType): ResolvedType {
+                const members = createMap<Symbol>();
+                for (const prop of getPropertiesOfObjectType(type)) {
+                    if (!(prop.name in diff.members)) {
+                        members[prop.name] = prop;
                     }
                 }
+                const stringIndexInfo = getIndexInfoOfType(diff, IndexKind.String) ? undefined : getIndexInfoOfType(type, IndexKind.String);
+                const numberIndexInfo = getIndexInfoOfType(diff, IndexKind.Number) ? undefined : getIndexInfoOfType(type, IndexKind.Number);
+                return createAnonymousType(type.symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
             }
 
             function inferFromProperties(source: Type, target: Type) {

From 4bc4a008bbc9c8fdb55e3a2f7bf9e8c2745ed30e Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 11 Oct 2016 16:14:47 -0700
Subject: [PATCH 035/224] Test spread type inference+more index signature tests

---
 .../spread/objectSpreadIndexSignature.ts      |  4 ++
 .../types/spread/objectSpreadInference.ts     | 59 +++++++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 tests/cases/conformance/types/spread/objectSpreadInference.ts

diff --git a/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts b/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
index d6f9f511c7b9e..daf8e4e63c573 100644
--- a/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
@@ -18,3 +18,7 @@ interface Indexed2 {
 }
 let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
 let nb: number | boolean = ii[1001];
+
+function f<T>(t: T) {
+    let i: { ...T, [n: number]: string };
+}
diff --git a/tests/cases/conformance/types/spread/objectSpreadInference.ts b/tests/cases/conformance/types/spread/objectSpreadInference.ts
new file mode 100644
index 0000000000000..1984193241988
--- /dev/null
+++ b/tests/cases/conformance/types/spread/objectSpreadInference.ts
@@ -0,0 +1,59 @@
+interface Result<T,U,V> {
+    t: T;
+    u: U;
+    v: V;
+}
+declare function infer<T,U,V>(tuv: { ...T, ...U, a: V }): { t: T, u: U, v: V };
+declare function infer2<T,U,V>(utv: { ...U, a: V, ...T }): { t: T, u: U, v: V };
+function generic<W, X, Y>(w: W, x: X, y: Y) {
+    // should infer { t: {}, u: {}, v: {} } because there is no trailing type parameter
+    return infer({ ...w, ...x, a: y, b: "different type" });
+}
+let b: { b: number };
+let c: { c: number };
+// should infer { t: {}, u: { b: number, c: number }, v: number }
+let i1 = infer({ ...b, ...c, a: 12 });
+// should infer { t: { a: number, b: number, c: number }, u: {}, v: {} }
+let i2 = infer2({ ...b, ...c, a: 12 });
+// should infer { t: {}, u: {}, v: {} }
+let i3 = generic(b, c, { a: 12 });
+
+interface Preserved {
+    kind: 0 | 1 | 2 | 3;
+}
+class C implements Preserved {
+    kind: 0 = 0;
+    a = 1;
+    method() { return "C"; }
+}
+declare function revive<T extends Preserved>(t: { ...T }): T;
+function genericRevive<U extends Preserved>(u: U) {
+    let us: { ...U };
+    return revive(us);
+}
+// result should not have `method`
+let result = revive({ a: 12, kind: 0 });
+// result2 should be of type C and have `method`
+let result2 = revive<C>({ a: 12, kind: 0 });
+
+declare function destructureRevive<T extends Preserved>(t: { ...T, a: number }): T;
+function genericDestructureRevive<U extends Preserved & { a: number }>(u: U) {
+    let us: { ...U };
+    return destructureRevive(us);
+}
+// result3 is just `Preserved` because `a` and `method` both get removed
+let result3 = destructureRevive({ a: 12, kind: 0 });
+// result4 is still C -- a is not removed -- because we specified the argument explicitly
+let result4 = destructureRevive<C>({ a: 12, kind: 0 });
+result4.method();
+result4.a;
+
+declare function removeIndexSignature<T>(t: { ...T, a: number, [s: string]: number, [n: number]: number }): T;
+interface I {
+    a: number;
+    b: number;
+    [s: string]: number;
+    [n: number]: number;
+}
+let i: I;
+let result5 = removeIndexSignature(i);

From 7417af6f15cb0abfd547932378f78250d92838d0 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 11 Oct 2016 16:15:37 -0700
Subject: [PATCH 036/224] Update baselines

---
 .../reference/objectSpreadIndexSignature.js   |   7 +
 .../objectSpreadIndexSignature.symbols        |  12 +
 .../objectSpreadIndexSignature.types          |  18 +-
 .../reference/objectSpreadInference.js        | 111 +++++++
 .../reference/objectSpreadInference.symbols   | 241 +++++++++++++++
 .../reference/objectSpreadInference.types     | 282 ++++++++++++++++++
 6 files changed, 668 insertions(+), 3 deletions(-)
 create mode 100644 tests/baselines/reference/objectSpreadInference.js
 create mode 100644 tests/baselines/reference/objectSpreadInference.symbols
 create mode 100644 tests/baselines/reference/objectSpreadInference.types

diff --git a/tests/baselines/reference/objectSpreadIndexSignature.js b/tests/baselines/reference/objectSpreadIndexSignature.js
index b5ec35277e0c3..709cd9446d8da 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.js
+++ b/tests/baselines/reference/objectSpreadIndexSignature.js
@@ -19,6 +19,10 @@ interface Indexed2 {
 }
 let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
 let nb: number | boolean = ii[1001];
+
+function f<T>(t: T) {
+    let i: { ...T, [n: number]: string };
+}
 
 
 //// [objectSpreadIndexSignature.js]
@@ -35,3 +39,6 @@ n = i[101];
 n = i.b;
 var ii;
 var nb = ii[1001];
+function f(t) {
+    var i;
+}
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.symbols b/tests/baselines/reference/objectSpreadIndexSignature.symbols
index a3510f9865830..e76ad3e1b1362 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.symbols
+++ b/tests/baselines/reference/objectSpreadIndexSignature.symbols
@@ -69,3 +69,15 @@ let nb: number | boolean = ii[1001];
 >nb : Symbol(nb, Decl(objectSpreadIndexSignature.ts, 19, 3))
 >ii : Symbol(ii, Decl(objectSpreadIndexSignature.ts, 18, 3))
 
+function f<T>(t: T) {
+>f : Symbol(f, Decl(objectSpreadIndexSignature.ts, 19, 36))
+>T : Symbol(T, Decl(objectSpreadIndexSignature.ts, 21, 11))
+>t : Symbol(t, Decl(objectSpreadIndexSignature.ts, 21, 14))
+>T : Symbol(T, Decl(objectSpreadIndexSignature.ts, 21, 11))
+
+    let i: { ...T, [n: number]: string };
+>i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 22, 7))
+>T : Symbol(T, Decl(objectSpreadIndexSignature.ts, 21, 11))
+>n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 22, 20))
+}
+
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.types b/tests/baselines/reference/objectSpreadIndexSignature.types
index 6e9ba881db1fb..f646361765d4b 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.types
+++ b/tests/baselines/reference/objectSpreadIndexSignature.types
@@ -9,7 +9,7 @@ class C {
 >c : boolean
 }
 let c: { ...C, b: string, c?: string, [n: number]: string };
->c : { [n: number]: string; b: string; c: string | boolean; a: number; }
+>c : { [x: number]: string; b: string; c: string | boolean; a: number; }
 >C : C
 >b : string
 >c : string
@@ -18,13 +18,13 @@ let c: { ...C, b: string, c?: string, [n: number]: string };
 let n: number = c.a;
 >n : number
 >c.a : number
->c : { [n: number]: string; b: string; c: string | boolean; a: number; }
+>c : { [x: number]: string; b: string; c: string | boolean; a: number; }
 >a : number
 
 let s: string = c[12];
 >s : string
 >c[12] : string
->c : { [n: number]: string; b: string; c: string | boolean; a: number; }
+>c : { [x: number]: string; b: string; c: string | boolean; a: number; }
 >12 : 12
 
 interface Indexed {
@@ -77,3 +77,15 @@ let nb: number | boolean = ii[1001];
 >ii : { [x: string]: number | boolean; b: boolean; d: number; c: boolean; a: number; }
 >1001 : 1001
 
+function f<T>(t: T) {
+>f : <T>(t: T) => void
+>T : T
+>t : T
+>T : T
+
+    let i: { ...T, [n: number]: string };
+>i : { ...T; [n: number]: string; }
+>T : T
+>n : number
+}
+
diff --git a/tests/baselines/reference/objectSpreadInference.js b/tests/baselines/reference/objectSpreadInference.js
new file mode 100644
index 0000000000000..06b17cfa1f948
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadInference.js
@@ -0,0 +1,111 @@
+//// [objectSpreadInference.ts]
+interface Result<T,U,V> {
+    t: T;
+    u: U;
+    v: V;
+}
+declare function infer<T,U,V>(tuv: { ...T, ...U, a: V }): { t: T, u: U, v: V };
+declare function infer2<T,U,V>(utv: { ...U, a: V, ...T }): { t: T, u: U, v: V };
+function generic<W, X, Y>(w: W, x: X, y: Y) {
+    // should infer { t: {}, u: {}, v: {} } because there is no trailing type parameter
+    return infer({ ...w, ...x, a: y, b: "different type" });
+}
+let b: { b: number };
+let c: { c: number };
+// should infer { t: {}, u: { b: number, c: number }, v: number }
+let i1 = infer({ ...b, ...c, a: 12 });
+// should infer { t: { a: number, b: number, c: number }, u: {}, v: {} }
+let i2 = infer2({ ...b, ...c, a: 12 });
+// should infer { t: {}, u: {}, v: {} }
+let i3 = generic(b, c, { a: 12 });
+
+interface Preserved {
+    kind: 0 | 1 | 2 | 3;
+}
+class C implements Preserved {
+    kind: 0 = 0;
+    a = 1;
+    method() { return "C"; }
+}
+declare function revive<T extends Preserved>(t: { ...T }): T;
+function genericRevive<U extends Preserved>(u: U) {
+    let us: { ...U };
+    return revive(us);
+}
+// result should not have `method`
+let result = revive({ a: 12, kind: 0 });
+// result2 should be of type C and have `method`
+let result2 = revive<C>({ a: 12, kind: 0 });
+
+declare function destructureRevive<T extends Preserved>(t: { ...T, a: number }): T;
+function genericDestructureRevive<U extends Preserved & { a: number }>(u: U) {
+    let us: { ...U };
+    return destructureRevive(us);
+}
+// result3 is just `Preserved` because `a` and `method` both get removed
+let result3 = destructureRevive({ a: 12, kind: 0 });
+// result4 is still C -- a is not removed -- because we specified the argument explicitly
+let result4 = destructureRevive<C>({ a: 12, kind: 0 });
+result4.method();
+result4.a;
+
+declare function removeIndexSignature<T>(t: { ...T, a: number, [s: string]: number, [n: number]: number }): T;
+interface I {
+    a: number;
+    b: number;
+    [s: string]: number;
+    [n: number]: number;
+}
+let i: I;
+let result5 = removeIndexSignature(i);
+
+
+//// [objectSpreadInference.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+function generic(w, x, y) {
+    // should infer { t: {}, u: {}, v: {} } because there is no trailing type parameter
+    return infer(__assign({}, w, x, { a: y, b: "different type" }));
+}
+var b;
+var c;
+// should infer { t: {}, u: { b: number, c: number }, v: number }
+var i1 = infer(__assign({}, b, c, { a: 12 }));
+// should infer { t: { a: number, b: number, c: number }, u: {}, v: {} }
+var i2 = infer2(__assign({}, b, c, { a: 12 }));
+// should infer { t: {}, u: {}, v: {} }
+var i3 = generic(b, c, { a: 12 });
+var C = (function () {
+    function C() {
+        this.kind = 0;
+        this.a = 1;
+    }
+    C.prototype.method = function () { return "C"; };
+    return C;
+}());
+function genericRevive(u) {
+    var us;
+    return revive(us);
+}
+// result should not have `method`
+var result = revive({ a: 12, kind: 0 });
+// result2 should be of type C and have `method`
+var result2 = revive({ a: 12, kind: 0 });
+function genericDestructureRevive(u) {
+    var us;
+    return destructureRevive(us);
+}
+// result3 is just `Preserved` because `a` and `method` both get removed
+var result3 = destructureRevive({ a: 12, kind: 0 });
+// result4 is still C -- a is not removed -- because we specified the argument explicitly
+var result4 = destructureRevive({ a: 12, kind: 0 });
+result4.method();
+result4.a;
+var i;
+var result5 = removeIndexSignature(i);
diff --git a/tests/baselines/reference/objectSpreadInference.symbols b/tests/baselines/reference/objectSpreadInference.symbols
new file mode 100644
index 0000000000000..f03cd6b44e11a
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadInference.symbols
@@ -0,0 +1,241 @@
+=== tests/cases/conformance/types/spread/objectSpreadInference.ts ===
+interface Result<T,U,V> {
+>Result : Symbol(Result, Decl(objectSpreadInference.ts, 0, 0))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 0, 17))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 0, 19))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 0, 21))
+
+    t: T;
+>t : Symbol(Result.t, Decl(objectSpreadInference.ts, 0, 25))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 0, 17))
+
+    u: U;
+>u : Symbol(Result.u, Decl(objectSpreadInference.ts, 1, 9))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 0, 19))
+
+    v: V;
+>v : Symbol(Result.v, Decl(objectSpreadInference.ts, 2, 9))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 0, 21))
+}
+declare function infer<T,U,V>(tuv: { ...T, ...U, a: V }): { t: T, u: U, v: V };
+>infer : Symbol(infer, Decl(objectSpreadInference.ts, 4, 1))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 5, 23))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 5, 25))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 5, 27))
+>tuv : Symbol(tuv, Decl(objectSpreadInference.ts, 5, 30))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 5, 23))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 5, 25))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 5, 48))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 5, 27))
+>t : Symbol(t, Decl(objectSpreadInference.ts, 5, 59))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 5, 23))
+>u : Symbol(u, Decl(objectSpreadInference.ts, 5, 65))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 5, 25))
+>v : Symbol(v, Decl(objectSpreadInference.ts, 5, 71))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 5, 27))
+
+declare function infer2<T,U,V>(utv: { ...U, a: V, ...T }): { t: T, u: U, v: V };
+>infer2 : Symbol(infer2, Decl(objectSpreadInference.ts, 5, 79))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 6, 24))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 6, 26))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 6, 28))
+>utv : Symbol(utv, Decl(objectSpreadInference.ts, 6, 31))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 6, 26))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 6, 43))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 6, 28))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 6, 24))
+>t : Symbol(t, Decl(objectSpreadInference.ts, 6, 60))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 6, 24))
+>u : Symbol(u, Decl(objectSpreadInference.ts, 6, 66))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 6, 26))
+>v : Symbol(v, Decl(objectSpreadInference.ts, 6, 72))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 6, 28))
+
+function generic<W, X, Y>(w: W, x: X, y: Y) {
+>generic : Symbol(generic, Decl(objectSpreadInference.ts, 6, 80))
+>W : Symbol(W, Decl(objectSpreadInference.ts, 7, 17))
+>X : Symbol(X, Decl(objectSpreadInference.ts, 7, 19))
+>Y : Symbol(Y, Decl(objectSpreadInference.ts, 7, 22))
+>w : Symbol(w, Decl(objectSpreadInference.ts, 7, 26))
+>W : Symbol(W, Decl(objectSpreadInference.ts, 7, 17))
+>x : Symbol(x, Decl(objectSpreadInference.ts, 7, 31))
+>X : Symbol(X, Decl(objectSpreadInference.ts, 7, 19))
+>y : Symbol(y, Decl(objectSpreadInference.ts, 7, 37))
+>Y : Symbol(Y, Decl(objectSpreadInference.ts, 7, 22))
+
+    // should infer { t: {}, u: {}, v: {} } because there is no trailing type parameter
+    return infer({ ...w, ...x, a: y, b: "different type" });
+>infer : Symbol(infer, Decl(objectSpreadInference.ts, 4, 1))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 9, 30))
+>y : Symbol(y, Decl(objectSpreadInference.ts, 7, 37))
+>b : Symbol(b, Decl(objectSpreadInference.ts, 9, 36))
+}
+let b: { b: number };
+>b : Symbol(b, Decl(objectSpreadInference.ts, 11, 3))
+>b : Symbol(b, Decl(objectSpreadInference.ts, 11, 8))
+
+let c: { c: number };
+>c : Symbol(c, Decl(objectSpreadInference.ts, 12, 3))
+>c : Symbol(c, Decl(objectSpreadInference.ts, 12, 8))
+
+// should infer { t: {}, u: { b: number, c: number }, v: number }
+let i1 = infer({ ...b, ...c, a: 12 });
+>i1 : Symbol(i1, Decl(objectSpreadInference.ts, 14, 3))
+>infer : Symbol(infer, Decl(objectSpreadInference.ts, 4, 1))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 14, 28))
+
+// should infer { t: { a: number, b: number, c: number }, u: {}, v: {} }
+let i2 = infer2({ ...b, ...c, a: 12 });
+>i2 : Symbol(i2, Decl(objectSpreadInference.ts, 16, 3))
+>infer2 : Symbol(infer2, Decl(objectSpreadInference.ts, 5, 79))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 16, 29))
+
+// should infer { t: {}, u: {}, v: {} }
+let i3 = generic(b, c, { a: 12 });
+>i3 : Symbol(i3, Decl(objectSpreadInference.ts, 18, 3))
+>generic : Symbol(generic, Decl(objectSpreadInference.ts, 6, 80))
+>b : Symbol(b, Decl(objectSpreadInference.ts, 11, 3))
+>c : Symbol(c, Decl(objectSpreadInference.ts, 12, 3))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 18, 24))
+
+interface Preserved {
+>Preserved : Symbol(Preserved, Decl(objectSpreadInference.ts, 18, 34))
+
+    kind: 0 | 1 | 2 | 3;
+>kind : Symbol(Preserved.kind, Decl(objectSpreadInference.ts, 20, 21))
+}
+class C implements Preserved {
+>C : Symbol(C, Decl(objectSpreadInference.ts, 22, 1))
+>Preserved : Symbol(Preserved, Decl(objectSpreadInference.ts, 18, 34))
+
+    kind: 0 = 0;
+>kind : Symbol(C.kind, Decl(objectSpreadInference.ts, 23, 30))
+
+    a = 1;
+>a : Symbol(C.a, Decl(objectSpreadInference.ts, 24, 16))
+
+    method() { return "C"; }
+>method : Symbol(C.method, Decl(objectSpreadInference.ts, 25, 10))
+}
+declare function revive<T extends Preserved>(t: { ...T }): T;
+>revive : Symbol(revive, Decl(objectSpreadInference.ts, 27, 1))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 28, 24))
+>Preserved : Symbol(Preserved, Decl(objectSpreadInference.ts, 18, 34))
+>t : Symbol(t, Decl(objectSpreadInference.ts, 28, 45))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 28, 24))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 28, 24))
+
+function genericRevive<U extends Preserved>(u: U) {
+>genericRevive : Symbol(genericRevive, Decl(objectSpreadInference.ts, 28, 61))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 29, 23))
+>Preserved : Symbol(Preserved, Decl(objectSpreadInference.ts, 18, 34))
+>u : Symbol(u, Decl(objectSpreadInference.ts, 29, 44))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 29, 23))
+
+    let us: { ...U };
+>us : Symbol(us, Decl(objectSpreadInference.ts, 30, 7))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 29, 23))
+
+    return revive(us);
+>revive : Symbol(revive, Decl(objectSpreadInference.ts, 27, 1))
+>us : Symbol(us, Decl(objectSpreadInference.ts, 30, 7))
+}
+// result should not have `method`
+let result = revive({ a: 12, kind: 0 });
+>result : Symbol(result, Decl(objectSpreadInference.ts, 34, 3))
+>revive : Symbol(revive, Decl(objectSpreadInference.ts, 27, 1))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 34, 21))
+>kind : Symbol(kind, Decl(objectSpreadInference.ts, 34, 28))
+
+// result2 should be of type C and have `method`
+let result2 = revive<C>({ a: 12, kind: 0 });
+>result2 : Symbol(result2, Decl(objectSpreadInference.ts, 36, 3))
+>revive : Symbol(revive, Decl(objectSpreadInference.ts, 27, 1))
+>C : Symbol(C, Decl(objectSpreadInference.ts, 22, 1))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 36, 25))
+>kind : Symbol(kind, Decl(objectSpreadInference.ts, 36, 32))
+
+declare function destructureRevive<T extends Preserved>(t: { ...T, a: number }): T;
+>destructureRevive : Symbol(destructureRevive, Decl(objectSpreadInference.ts, 36, 44))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 38, 35))
+>Preserved : Symbol(Preserved, Decl(objectSpreadInference.ts, 18, 34))
+>t : Symbol(t, Decl(objectSpreadInference.ts, 38, 56))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 38, 35))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 38, 66))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 38, 35))
+
+function genericDestructureRevive<U extends Preserved & { a: number }>(u: U) {
+>genericDestructureRevive : Symbol(genericDestructureRevive, Decl(objectSpreadInference.ts, 38, 83))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 39, 34))
+>Preserved : Symbol(Preserved, Decl(objectSpreadInference.ts, 18, 34))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 39, 57))
+>u : Symbol(u, Decl(objectSpreadInference.ts, 39, 71))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 39, 34))
+
+    let us: { ...U };
+>us : Symbol(us, Decl(objectSpreadInference.ts, 40, 7))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 39, 34))
+
+    return destructureRevive(us);
+>destructureRevive : Symbol(destructureRevive, Decl(objectSpreadInference.ts, 36, 44))
+>us : Symbol(us, Decl(objectSpreadInference.ts, 40, 7))
+}
+// result3 is just `Preserved` because `a` and `method` both get removed
+let result3 = destructureRevive({ a: 12, kind: 0 });
+>result3 : Symbol(result3, Decl(objectSpreadInference.ts, 44, 3))
+>destructureRevive : Symbol(destructureRevive, Decl(objectSpreadInference.ts, 36, 44))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 44, 33))
+>kind : Symbol(kind, Decl(objectSpreadInference.ts, 44, 40))
+
+// result4 is still C -- a is not removed -- because we specified the argument explicitly
+let result4 = destructureRevive<C>({ a: 12, kind: 0 });
+>result4 : Symbol(result4, Decl(objectSpreadInference.ts, 46, 3))
+>destructureRevive : Symbol(destructureRevive, Decl(objectSpreadInference.ts, 36, 44))
+>C : Symbol(C, Decl(objectSpreadInference.ts, 22, 1))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 46, 36))
+>kind : Symbol(kind, Decl(objectSpreadInference.ts, 46, 43))
+
+result4.method();
+>result4.method : Symbol(C.method, Decl(objectSpreadInference.ts, 25, 10))
+>result4 : Symbol(result4, Decl(objectSpreadInference.ts, 46, 3))
+>method : Symbol(C.method, Decl(objectSpreadInference.ts, 25, 10))
+
+result4.a;
+>result4.a : Symbol(C.a, Decl(objectSpreadInference.ts, 24, 16))
+>result4 : Symbol(result4, Decl(objectSpreadInference.ts, 46, 3))
+>a : Symbol(C.a, Decl(objectSpreadInference.ts, 24, 16))
+
+declare function removeIndexSignature<T>(t: { ...T, a: number, [s: string]: number, [n: number]: number }): T;
+>removeIndexSignature : Symbol(removeIndexSignature, Decl(objectSpreadInference.ts, 48, 10))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 50, 38))
+>t : Symbol(t, Decl(objectSpreadInference.ts, 50, 41))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 50, 38))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 50, 51))
+>s : Symbol(s, Decl(objectSpreadInference.ts, 50, 64))
+>n : Symbol(n, Decl(objectSpreadInference.ts, 50, 85))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 50, 38))
+
+interface I {
+>I : Symbol(I, Decl(objectSpreadInference.ts, 50, 110))
+
+    a: number;
+>a : Symbol(I.a, Decl(objectSpreadInference.ts, 51, 13))
+
+    b: number;
+>b : Symbol(I.b, Decl(objectSpreadInference.ts, 52, 14))
+
+    [s: string]: number;
+>s : Symbol(s, Decl(objectSpreadInference.ts, 54, 5))
+
+    [n: number]: number;
+>n : Symbol(n, Decl(objectSpreadInference.ts, 55, 5))
+}
+let i: I;
+>i : Symbol(i, Decl(objectSpreadInference.ts, 57, 3))
+>I : Symbol(I, Decl(objectSpreadInference.ts, 50, 110))
+
+let result5 = removeIndexSignature(i);
+>result5 : Symbol(result5, Decl(objectSpreadInference.ts, 58, 3))
+>removeIndexSignature : Symbol(removeIndexSignature, Decl(objectSpreadInference.ts, 48, 10))
+>i : Symbol(i, Decl(objectSpreadInference.ts, 57, 3))
+
diff --git a/tests/baselines/reference/objectSpreadInference.types b/tests/baselines/reference/objectSpreadInference.types
new file mode 100644
index 0000000000000..55303119932e1
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadInference.types
@@ -0,0 +1,282 @@
+=== tests/cases/conformance/types/spread/objectSpreadInference.ts ===
+interface Result<T,U,V> {
+>Result : Result<T, U, V>
+>T : T
+>U : U
+>V : V
+
+    t: T;
+>t : T
+>T : T
+
+    u: U;
+>u : U
+>U : U
+
+    v: V;
+>v : V
+>V : V
+}
+declare function infer<T,U,V>(tuv: { ...T, ...U, a: V }): { t: T, u: U, v: V };
+>infer : <T, U, V>(tuv: { ...T; ...U; a: V; }) => { t: T; u: U; v: V; }
+>T : T
+>U : U
+>V : V
+>tuv : { ...T; ...U; a: V; }
+>T : T
+>U : U
+>a : V
+>V : V
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+declare function infer2<T,U,V>(utv: { ...U, a: V, ...T }): { t: T, u: U, v: V };
+>infer2 : <T, U, V>(utv: { ...U; a: V; ...T }) => { t: T; u: U; v: V; }
+>T : T
+>U : U
+>V : V
+>utv : { ...U; a: V; ...T }
+>U : U
+>a : V
+>V : V
+>T : T
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+function generic<W, X, Y>(w: W, x: X, y: Y) {
+>generic : <W, X, Y>(w: W, x: X, y: Y) => { t: {}; u: {}; v: {}; }
+>W : W
+>X : X
+>Y : Y
+>w : W
+>W : W
+>x : X
+>X : X
+>y : Y
+>Y : Y
+
+    // should infer { t: {}, u: {}, v: {} } because there is no trailing type parameter
+    return infer({ ...w, ...x, a: y, b: "different type" });
+>infer({ ...w, ...x, a: y, b: "different type" }) : { t: {}; u: {}; v: {}; }
+>infer : <T, U, V>(tuv: { ...T; ...U; a: V; }) => { t: T; u: U; v: V; }
+>{ ...w, ...x, a: y, b: "different type" } : { ...W; ...X; a: Y; b: string; }
+>w : any
+>x : any
+>a : Y
+>y : Y
+>b : string
+>"different type" : "different type"
+}
+let b: { b: number };
+>b : { b: number; }
+>b : number
+
+let c: { c: number };
+>c : { c: number; }
+>c : number
+
+// should infer { t: {}, u: { b: number, c: number }, v: number }
+let i1 = infer({ ...b, ...c, a: 12 });
+>i1 : { t: {}; u: { c: number; b: number; }; v: number; }
+>infer({ ...b, ...c, a: 12 }) : { t: {}; u: { c: number; b: number; }; v: number; }
+>infer : <T, U, V>(tuv: { ...T; ...U; a: V; }) => { t: T; u: U; v: V; }
+>{ ...b, ...c, a: 12 } : { a: number; c: number; b: number; }
+>b : any
+>c : any
+>a : number
+>12 : 12
+
+// should infer { t: { a: number, b: number, c: number }, u: {}, v: {} }
+let i2 = infer2({ ...b, ...c, a: 12 });
+>i2 : { t: { a: number; c: number; b: number; }; u: {}; v: {}; }
+>infer2({ ...b, ...c, a: 12 }) : { t: { a: number; c: number; b: number; }; u: {}; v: {}; }
+>infer2 : <T, U, V>(utv: { ...U; a: V; ...T }) => { t: T; u: U; v: V; }
+>{ ...b, ...c, a: 12 } : { a: number; c: number; b: number; }
+>b : any
+>c : any
+>a : number
+>12 : 12
+
+// should infer { t: {}, u: {}, v: {} }
+let i3 = generic(b, c, { a: 12 });
+>i3 : { t: {}; u: {}; v: {}; }
+>generic(b, c, { a: 12 }) : { t: {}; u: {}; v: {}; }
+>generic : <W, X, Y>(w: W, x: X, y: Y) => { t: {}; u: {}; v: {}; }
+>b : { b: number; }
+>c : { c: number; }
+>{ a: 12 } : { a: number; }
+>a : number
+>12 : 12
+
+interface Preserved {
+>Preserved : Preserved
+
+    kind: 0 | 1 | 2 | 3;
+>kind : 0 | 1 | 2 | 3
+}
+class C implements Preserved {
+>C : C
+>Preserved : Preserved
+
+    kind: 0 = 0;
+>kind : 0
+>0 : 0
+
+    a = 1;
+>a : number
+>1 : 1
+
+    method() { return "C"; }
+>method : () => string
+>"C" : "C"
+}
+declare function revive<T extends Preserved>(t: { ...T }): T;
+>revive : <T extends Preserved>(t: { ...T }) => T
+>T : T
+>Preserved : Preserved
+>t : { ...T }
+>T : T
+>T : T
+
+function genericRevive<U extends Preserved>(u: U) {
+>genericRevive : <U extends Preserved>(u: U) => U
+>U : U
+>Preserved : Preserved
+>u : U
+>U : U
+
+    let us: { ...U };
+>us : { ...U }
+>U : U
+
+    return revive(us);
+>revive(us) : U
+>revive : <T extends Preserved>(t: { ...T }) => T
+>us : { ...U }
+}
+// result should not have `method`
+let result = revive({ a: 12, kind: 0 });
+>result : { a: number; kind: 0; }
+>revive({ a: 12, kind: 0 }) : { a: number; kind: 0; }
+>revive : <T extends Preserved>(t: { ...T }) => T
+>{ a: 12, kind: 0 } : { a: number; kind: 0; }
+>a : number
+>12 : 12
+>kind : number
+>0 : 0
+
+// result2 should be of type C and have `method`
+let result2 = revive<C>({ a: 12, kind: 0 });
+>result2 : C
+>revive<C>({ a: 12, kind: 0 }) : C
+>revive : <T extends Preserved>(t: { ...T }) => T
+>C : C
+>{ a: 12, kind: 0 } : { a: number; kind: 0; }
+>a : number
+>12 : 12
+>kind : number
+>0 : 0
+
+declare function destructureRevive<T extends Preserved>(t: { ...T, a: number }): T;
+>destructureRevive : <T extends Preserved>(t: { ...T; a: number; }) => T
+>T : T
+>Preserved : Preserved
+>t : { ...T; a: number; }
+>T : T
+>a : number
+>T : T
+
+function genericDestructureRevive<U extends Preserved & { a: number }>(u: U) {
+>genericDestructureRevive : <U extends Preserved & { a: number; }>(u: U) => Preserved
+>U : U
+>Preserved : Preserved
+>a : number
+>u : U
+>U : U
+
+    let us: { ...U };
+>us : { ...U }
+>U : U
+
+    return destructureRevive(us);
+>destructureRevive(us) : Preserved
+>destructureRevive : <T extends Preserved>(t: { ...T; a: number; }) => T
+>us : { ...U }
+}
+// result3 is just `Preserved` because `a` and `method` both get removed
+let result3 = destructureRevive({ a: 12, kind: 0 });
+>result3 : { kind: 0; }
+>destructureRevive({ a: 12, kind: 0 }) : { kind: 0; }
+>destructureRevive : <T extends Preserved>(t: { ...T; a: number; }) => T
+>{ a: 12, kind: 0 } : { a: number; kind: 0; }
+>a : number
+>12 : 12
+>kind : number
+>0 : 0
+
+// result4 is still C -- a is not removed -- because we specified the argument explicitly
+let result4 = destructureRevive<C>({ a: 12, kind: 0 });
+>result4 : C
+>destructureRevive<C>({ a: 12, kind: 0 }) : C
+>destructureRevive : <T extends Preserved>(t: { ...T; a: number; }) => T
+>C : C
+>{ a: 12, kind: 0 } : { a: number; kind: 0; }
+>a : number
+>12 : 12
+>kind : number
+>0 : 0
+
+result4.method();
+>result4.method() : string
+>result4.method : () => string
+>result4 : C
+>method : () => string
+
+result4.a;
+>result4.a : number
+>result4 : C
+>a : number
+
+declare function removeIndexSignature<T>(t: { ...T, a: number, [s: string]: number, [n: number]: number }): T;
+>removeIndexSignature : <T>(t: { ...T; [s: string]: number; [n: number]: number; a: number; }) => T
+>T : T
+>t : { ...T; [s: string]: number; [n: number]: number; a: number; }
+>T : T
+>a : number
+>s : string
+>n : number
+>T : T
+
+interface I {
+>I : I
+
+    a: number;
+>a : number
+
+    b: number;
+>b : number
+
+    [s: string]: number;
+>s : string
+
+    [n: number]: number;
+>n : number
+}
+let i: I;
+>i : I
+>I : I
+
+let result5 = removeIndexSignature(i);
+>result5 : { b: number; }
+>removeIndexSignature(i) : { b: number; }
+>removeIndexSignature : <T>(t: { ...T; [s: string]: number; [n: number]: number; a: number; }) => T
+>i : I
+

From ce373d904a0dc6abd79736ac8bac12af647f8572 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 11 Oct 2016 16:16:36 -0700
Subject: [PATCH 037/224] Revert lib.d.ts error message baseline (unrelated)

It should fixed in a separate PR.
---
 .../reference/variableDeclarationInStrictMode1.errors.txt     | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
index 46782aaa1d69d..c47ac71f74869 100644
--- a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
+++ b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
@@ -1,4 +1,4 @@
-lib.d.ts(32,18): error TS2300: Duplicate identifier 'eval'.
+lib.d.ts(28,18): error TS2300: Duplicate identifier 'eval'.
 tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS1100: Invalid use of 'eval' in strict mode.
 tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS2300: Duplicate identifier 'eval'.
 
@@ -9,4 +9,4 @@ tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS2300: Dup
         ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
         ~~~~
-!!! error TS2300: Duplicate identifier 'eval'.
\ No newline at end of file
+!!! error TS2300: Duplicate identifier 'eval'.

From f73d906f18d2ba7f653e964739ed9cd9a4edc0f9 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Wed, 12 Oct 2016 07:56:05 -0700
Subject: [PATCH 038/224] Use a single ShimMap class, and indicate that
 iteration always yields string keys (which it did before too)

---
 src/compiler/collections.ts | 155 +++++++++++++++---------------------
 src/compiler/types.ts       |   6 +-
 2 files changed, 71 insertions(+), 90 deletions(-)

diff --git a/src/compiler/collections.ts b/src/compiler/collections.ts
index 40ae40bad0598..f7b23fe77c321 100644
--- a/src/compiler/collections.ts
+++ b/src/compiler/collections.ts
@@ -2,7 +2,7 @@
 /* @internal */
 namespace ts {
     // The global Map object. This may not be available, so we must test for it.
-    declare const Map: NumberMapConstructor & StringMapConstructor | undefined;
+    declare const Map: { new<K, V>(pairs?: [K, V][]): Map<K, V> } | undefined;
     const usingNativeMaps = typeof Map !== "undefined";
     // tslint:disable-next-line:no-in-operator
     const fullyFeaturedMaps = usingNativeMaps && "keys" in Map.prototype && "values" in Map.prototype && "entries" in Map.prototype;
@@ -19,99 +19,63 @@ namespace ts {
         next(): { value: T, done: false } | { value: never, done: true };
     }
 
-    export interface NumberMapConstructor {
-        /**
-         * Creates a new Map with number keys.
-         * If `pairs` is provided, each [key, value] pair will be added to the map.
-         */
-        new<K extends number, V>(pairs?: [K, V][]): Map<K, V>;
-    }
-
     /**
-     * In runtimes without Maps, this is implemented using a sparse array.
-     * This is generic over the key type because it is usually an enum.
+     * Provides Map-like functionality for ES5 runtimes.
+     * This is intentionally *not* a full Map shim, and doesn't provide iterators (which aren't available for IE Maps anyway).
+     * We can only efficiently support strings and number keys, and iteration will always yield stringified keys.
      */
-    export const NumberMap: NumberMapConstructor = usingNativeMaps ? Map : class ShimNumberMap<K extends number, V> implements Map<K, V> {
-        private data: { [key: number]: V } = [];
+    class ShimMap<K extends string | number, V> implements Map<K, V> {
+        private data = createDictionaryModeObject<V>();
+
+        /*
+        So long as `K extends string | number`, we can cast `key as string` and insert it into the map.
+        However, `forEach` will iterate over strings because values are stringified before being put in the map.
+        */
 
         constructor(pairs?: [K, V][]) {
             if (pairs) {
                 for (const [key, value] of pairs) {
-                    this.data[key as number] = value;
+                    this.data[key as string] = value;
                 }
             }
         }
 
-        clear() {
-            this.data = [];
+        clear(): void {
+            this.data = createDictionaryModeObject<V>();
         }
 
-        delete(key: K) {
-            delete this.data[key as number];
+        delete(key: K): void {
+            delete this.data[key as string];
         }
 
-        get(key: K) {
-            return this.data[key as number];
+        get(key: K): V {
+            return this.data[key as string];
         }
 
-        has(key: K) {
+        has(key: K): boolean {
             // tslint:disable-next-line:no-in-operator
-            return (key as number) in this.data;
+            return (key as string) in this.data;
         }
 
-        set(key: K, value: V) {
-            this.data[key as number] = value;
+        set(key: K, value: V): void {
+            this.data[key as string] = value;
         }
 
-        forEach(action: (value: V, key: K) => void) {
+        forEach(action: (value: V, key: string) => void): void {
             for (const key in this.data) {
-                action(this.data[key], key as any as K);
+                action(this.data[key], key);
             }
         }
-    };
-
-    export interface StringMapConstructor {
-        new<T>(pairs?: [string, T][]): Map<string, T>;
     }
-    /** In runtimes without Maps, this is implemented using an object. */
-    export const StringMap: StringMapConstructor = usingNativeMaps ? Map : class ShimStringMap<T> implements Map<string, T> {
-        private data = createDictionaryModeObject<T>();
-
-        constructor(pairs?: [string, T][]) {
-            if (pairs) {
-                for (const [key, value] of pairs) {
-                    this.data[key] = value;
-                }
-            }
-        }
-
-        clear() {
-            this.data = createDictionaryModeObject<T>();
-        }
-
-        delete(key: string) {
-            delete this.data[key];
-        }
-
-        get(key: string) {
-            return this.data[key];
-        }
 
-        has(key: string) {
-            // tslint:disable-next-line:no-in-operator
-            return key in this.data;
-        }
-
-        set(key: string, value: T) {
-            this.data[key] = value;
-        }
+    /**
+     * In runtimes without Maps, this is implemented using an object.
+     * `pairs` is an optional list of entries to add to the new map.
+     */
+    export const StringMap: { new<T>(pairs?: [string, T][]): Map<string, T>; } = usingNativeMaps ? Map : ShimMap;
 
-        forEach(f: (value: T, key: string) => void) {
-            for (const key in this.data) {
-                f(this.data[key], key);
-            }
-        }
-    };
+    /** This is generic over the key type because it is usually an enum. */
+    export const NumberMap: { new<K extends number, V>(pairs?: [K, V][]): Map<K, V> } = usingNativeMaps ? Map : ShimMap;
 
     const createObject = Object.create;
     function createDictionaryModeObject<T>(): MapLike<T> {
@@ -126,9 +90,12 @@ namespace ts {
         return map;
     }
 
-    /** Iterates over entries in the map, returning the first output of `getResult` that is not `undefined`. */
-    export const findInMap: <K, V, U>(map: Map<K, V>, getResult: (value: V, key: K) => U | undefined) => U | undefined = fullyFeaturedMaps
-        ? <K, V, U>(map: ES6Map<K, V>, f: (value: V, key: K) => U | undefined) => {
+    /**
+     * Iterates over entries in the map, returning the first output of `getResult` that is not `undefined`.
+     * Only works for strings because shims iterate with `for-in`.
+     */
+    export const findInMap: <V, U>(map: Map<string, V>, getResult: (value: V, key: string) => U | undefined) => U | undefined = fullyFeaturedMaps
+        ? <V, U>(map: ES6Map<string, V>, f: (value: V, key: string) => U | undefined) => {
             const iter = map.entries();
             while (true) {
                 const { value: pair, done } = iter.next();
@@ -142,7 +109,7 @@ namespace ts {
                 }
             }
         }
-        : <K, V, U>(map: Map<K, V>, f: (value: V, key: K) => U | undefined) => {
+        : <V, U>(map: Map<string, V>, f: (value: V, key: string) => U | undefined) => {
             let result: U | undefined;
             map.forEach((value, key) => {
                 if (result === undefined)
@@ -151,11 +118,14 @@ namespace ts {
             return result;
         };
 
-    /** Whether `predicate` is true for at least one entry in the map. */
-    export const someInMap: <K, V>(map: Map<K, V>, predicate: (value: V, key: K) => boolean) => boolean = fullyFeaturedMaps
-        ? <K, V>(map: ES6Map<K, V>, predicate: (value: V, key: K) => boolean) =>
+    /**
+     * Whether `predicate` is true for at least one entry in the map.
+     * Only works for strings because shims iterate with `for-in`.
+     */
+    export const someInMap: <V>(map: Map<string, V>, predicate: (value: V, key: string) => boolean) => boolean = fullyFeaturedMaps
+        ? <V>(map: ES6Map<string, V>, predicate: (value: V, key: string) => boolean) =>
             someInIterator(map.entries(), ([key, value]) => predicate(value, key))
-        : <K, V>(map: Map<K, V>, predicate: (value: V, key: K) => boolean) => {
+        : <V>(map: Map<string, V>, predicate: (value: V, key: string) => boolean) => {
             let found = false;
             map.forEach((value, key) => {
                 found = found || predicate(value, key);
@@ -163,10 +133,13 @@ namespace ts {
             return found;
         };
 
-    /** Whether `predicate` is true for at least one key in the map. */
-    export const someKeyInMap: <K>(map: Map<K, any>, predicate: (key: K) => boolean) => boolean = fullyFeaturedMaps
-        ? <K>(map: ES6Map<K, any>, predicate: (key: K) => boolean) => someInIterator(map.keys(), predicate)
-        : <K>(map: Map<K, any>, predicate: (key: K) => boolean) =>
+    /**
+     * Whether `predicate` is true for at least one key in the map.
+     * Only works for strings because shims iterate with `for-in`.
+     */
+    export const someKeyInMap: (map: Map<string, any>, predicate: (key: string) => boolean) => boolean = fullyFeaturedMaps
+        ? (map: ES6Map<string, any>, predicate: (key: string) => boolean) => someInIterator(map.keys(), predicate)
+        : (map: Map<string, any>, predicate: (key: string) => boolean) =>
             someInMap(map, (_value, key) => predicate(key));
 
     /** Whether `predicate` is true for at least one value in the map. */
@@ -190,19 +163,20 @@ namespace ts {
     /**
      * Equivalent to the ES6 code:
      * `for (const key of map.keys()) action(key);`
+     * Only works for strings because shims iterate with `for-in`.
      */
-    export const forEachKeyInMap: <K>(map: Map<K, any>, action: (key: K) => void) => void = fullyFeaturedMaps
-        ? <K>(map: ES6Map<K, any>, f: (key: K) => void) => {
-            const iter: Iterator<K> = map.keys();
+    export const forEachKeyInMap: (map: Map<string, any>, action: (key: string) => void) => void = fullyFeaturedMaps
+        ? (map: ES6Map<string, any>, action: (key: string) => void) => {
+            const iter: Iterator<string> = map.keys();
             while (true) {
                 const { value: key, done } = iter.next();
                 if (done) {
                     return;
                 }
-                f(key);
+                action(key);
             }
         }
-        : <K>(map: Map<K, any>, action: (key: K) => void) => {
+        : (map: Map<string, any>, action: (key: string) => void) => {
             map.forEach((_value, key) => action(key));
         };
 
@@ -310,14 +284,17 @@ namespace ts {
      * @param target A map to which properties should be copied.
      */
     export function copyMapEntriesFromTo<K, V>(source: Map<K, V>, target: Map<K, V>): void {
-        source.forEach((value, key) => {
+        source.forEach((value: V, key: K) => {
             target.set(key, value);
         });
     }
 
-    /** Equivalent to `Array.from(map.keys())`. */
-    export function keysOfMap<K>(map: Map<K, any>): K[] {
-        const keys: K[] = [];
+    /**
+     * Equivalent to `Array.from(map.keys())`.
+     * Only works for strings because shims iterate with `for-in`.
+     */
+    export function keysOfMap(map: Map<string, any>): string[] {
+        const keys: string[] = [];
         forEachKeyInMap(map, key => { keys.push(key); });
         return keys;
     }
@@ -442,7 +419,7 @@ namespace ts {
     }
 
     /** True if the maps have the same keys and values. */
-    export function mapsAreEqual<K, V>(left: Map<K, V>, right: Map<K, V>, valuesAreEqual?: (left: V, right: V) => boolean): boolean {
+    export function mapsAreEqual<V>(left: Map<string, V>, right: Map<string, V>, valuesAreEqual?: (left: V, right: V) => boolean): boolean {
         if (left === right) return true;
         if (!left || !right) return false;
         const someInLeftHasNoMatch = someInMap(left, (leftValue, leftKey) => {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 69061d42d6dc4..0e7f2fbc21360 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -18,7 +18,11 @@ namespace ts {
     export interface Map<K, V> {
         clear(): void;
         delete(key: K): void;
-        forEach(action: (value: V, key: K) => void): void;
+        /**
+         * Call `action` for each entry in the map.
+         * Since we use a `for-in` loop for our shims, `key` may be a string.
+         */
+        forEach(action: (value: V, key: K | string) => void): void;
         get(key: K): V;
         /**
          * Whether the key is in the map.

From 97dda6e0eb8568871cb38ede8cd90303beb7cade Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 12 Oct 2016 08:40:08 -0700
Subject: [PATCH 039/224] Remove emacs-added newline at end of baseline

---
 .../reference/variableDeclarationInStrictMode1.errors.txt       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
index c47ac71f74869..15c79179f70fd 100644
--- a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
+++ b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
@@ -9,4 +9,4 @@ tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS2300: Dup
         ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
         ~~~~
-!!! error TS2300: Duplicate identifier 'eval'.
+!!! error TS2300: Duplicate identifier 'eval'. 
\ No newline at end of file

From c5228d3435b3b7d528520f74735e354559879574 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 12 Oct 2016 08:58:49 -0700
Subject: [PATCH 040/224] Remove space at end of line in baseline

---
 .../reference/variableDeclarationInStrictMode1.errors.txt       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
index 15c79179f70fd..9dd9a8d41a1bf 100644
--- a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
+++ b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
@@ -9,4 +9,4 @@ tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS2300: Dup
         ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
         ~~~~
-!!! error TS2300: Duplicate identifier 'eval'. 
\ No newline at end of file
+!!! error TS2300: Duplicate identifier 'eval'.
\ No newline at end of file

From 5a037ad36867b5b5f8aad51bb12e9dd18005cf99 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 12 Oct 2016 09:00:17 -0700
Subject: [PATCH 041/224] Add numeric indexer to strings and remove lint

---
 src/compiler/checker.ts | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 93d9c19a71bc7..bfd6d78e89164 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5781,7 +5781,10 @@ namespace ts {
             if (id in spreadTypes) {
                 return spreadTypes[id];
             }
-            const right = types.pop();
+            let right = types.pop();
+            if (right.flags & TypeFlags.StringLike) {
+                right = createAnonymousType(symbol, emptySymbols, emptyArray, emptyArray, undefined, createIndexInfo(stringType, /*isReadonly*/ false));
+            }
             if (right.flags & TypeFlags.Any) {
                 return anyType;
             }
@@ -5801,16 +5804,13 @@ namespace ts {
                 return getIntersectionType(spreads, aliasSymbol, aliasTypeArguments);
             }
             if (right.flags & TypeFlags.Union) {
-                // TODO: types is mutable, so this block has to happen before the call to `const left = getSpreadType(...)`
-                // because that call consumes the array. It might be worthwhile to use a simple linked list here instead.
-                // It would avoid the slice+concat call that is needed here for multiple calls to getSpreadType.
                 const spreads = map((right as UnionType).types,
                                     t => getSpreadType(types.slice().concat([t]), symbol, aliasSymbol, aliasTypeArguments));
                 return getUnionType(spreads, /*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
             }
             const atBeginning = types.length === 0;
             const left = getSpreadType(types, symbol, aliasSymbol, aliasTypeArguments);
-            if (right.flags & TypeFlags.Primitive || left.flags & TypeFlags.Any) {
+            if (right.flags & (TypeFlags.Primitive & ~TypeFlags.StringLike) || left.flags & TypeFlags.Any) {
                 return left;
             }
             if (right.flags & TypeFlags.TypeParameter &&
@@ -5837,7 +5837,7 @@ namespace ts {
             if (left.flags & TypeFlags.Union) {
                 const spreads = map((left as UnionType).types,
                                   t => getSpreadType(types.slice().concat([t, right]), symbol, aliasSymbol, aliasTypeArguments));
-                return getUnionType(spreads, /*subTypeReduction*/ false, aliasSymbol, aliasTypeArguments);
+                return getUnionType(spreads, /*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
             }
             if (right.flags & TypeFlags.ObjectType && left.flags & TypeFlags.ObjectType) {
                 const members = createMap<Symbol>();
@@ -8100,7 +8100,7 @@ namespace ts {
                 if (source.flags & TypeFlags.Spread && target.flags & TypeFlags.Spread) {
                     // only the last type parameter is a valid inference site,
                     // and only if not followed by object literal properties.
-                    if((source as SpreadType).right.flags & TypeFlags.TypeParameter &&
+                    if ((source as SpreadType).right.flags & TypeFlags.TypeParameter &&
                        (target as SpreadType).right.flags & TypeFlags.TypeParameter) {
                         inferFromTypes((source as SpreadType).right, (target as SpreadType).right);
                     }
@@ -19053,7 +19053,6 @@ namespace ts {
         function getRootSymbols(symbol: Symbol): Symbol[] {
             if (symbol.flags & SymbolFlags.SyntheticProperty) {
                 if (symbol.syntheticKind === SyntheticSymbolKind.Spread) {
-                    const name = symbol.name;
                     const links = getSymbolLinks(symbol);
                     return [links.leftSpread, links.rightSpread];
                 }

From 1728ae1cbc0d454e6e47292e22dd6a6d885f74fa Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 12 Oct 2016 09:01:14 -0700
Subject: [PATCH 042/224] Update baselines with spread string's numeric
 indexers

---
 tests/baselines/reference/objectSpread.js     |  11 +-
 .../baselines/reference/objectSpread.symbols  | 247 +++++++++---------
 tests/baselines/reference/objectSpread.types  |  11 +-
 .../reference/objectSpreadNegative.errors.txt |   8 +-
 ...ariableDeclarationInStrictMode1.errors.txt |   2 +-
 .../conformance/types/spread/objectSpread.ts  |   6 +-
 6 files changed, 146 insertions(+), 139 deletions(-)

diff --git a/tests/baselines/reference/objectSpread.js b/tests/baselines/reference/objectSpread.js
index a09f5aa0fbb1a..efb73bcb35399 100644
--- a/tests/baselines/reference/objectSpread.js
+++ b/tests/baselines/reference/objectSpread.js
@@ -35,14 +35,16 @@ let getter: { a: number, c: number } =
     { ...op, c: 7 }
 getter.a = 12;
 
-// null, undefined, functions and primitives result in { }
+// null, undefined, functions and primitives besides string result in { }
 let spreadNull = { ...null };
 let spreadUndefind = { ...undefined };
 let spreadNum = { ...12 };
-let spreadStr = { ...'foo' };
 let spreadBool = { ...false };
 let spreadFunc = { ...(function () { }) };
 
+// strings get a numeric indexer: [n: number]: string
+let spreadStr = { ...'foo' };
+
 // methods are not enumerable
 class C { p = 1; m() { } }
 let c: C = new C()
@@ -128,13 +130,14 @@ var propertyNested = __assign({ a: __assign({}, o) });
 var op = { get a() { return 6; } };
 var getter = __assign({}, op, { c: 7 });
 getter.a = 12;
-// null, undefined, functions and primitives result in { }
+// null, undefined, functions and primitives besides string result in { }
 var spreadNull = __assign({}, null);
 var spreadUndefind = __assign({}, undefined);
 var spreadNum = __assign({}, 12);
-var spreadStr = __assign({}, 'foo');
 var spreadBool = __assign({}, false);
 var spreadFunc = __assign({}, (function () { }));
+// strings get a numeric indexer: [n: number]: string
+var spreadStr = __assign({}, 'foo');
 // methods are not enumerable
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/objectSpread.symbols b/tests/baselines/reference/objectSpread.symbols
index edb0b4c2f0813..d23016ddb1e15 100644
--- a/tests/baselines/reference/objectSpread.symbols
+++ b/tests/baselines/reference/objectSpread.symbols
@@ -150,7 +150,7 @@ getter.a = 12;
 >getter : Symbol(getter, Decl(objectSpread.ts, 32, 3))
 >a : Symbol(a, Decl(objectSpread.ts, 32, 13))
 
-// null, undefined, functions and primitives result in { }
+// null, undefined, functions and primitives besides string result in { }
 let spreadNull = { ...null };
 >spreadNull : Symbol(spreadNull, Decl(objectSpread.ts, 37, 3))
 
@@ -160,214 +160,215 @@ let spreadUndefind = { ...undefined };
 let spreadNum = { ...12 };
 >spreadNum : Symbol(spreadNum, Decl(objectSpread.ts, 39, 3))
 
-let spreadStr = { ...'foo' };
->spreadStr : Symbol(spreadStr, Decl(objectSpread.ts, 40, 3))
-
 let spreadBool = { ...false };
->spreadBool : Symbol(spreadBool, Decl(objectSpread.ts, 41, 3))
+>spreadBool : Symbol(spreadBool, Decl(objectSpread.ts, 40, 3))
 
 let spreadFunc = { ...(function () { }) };
->spreadFunc : Symbol(spreadFunc, Decl(objectSpread.ts, 42, 3))
+>spreadFunc : Symbol(spreadFunc, Decl(objectSpread.ts, 41, 3))
+
+// strings get a numeric indexer: [n: number]: string
+let spreadStr = { ...'foo' };
+>spreadStr : Symbol(spreadStr, Decl(objectSpread.ts, 44, 3))
 
 // methods are not enumerable
 class C { p = 1; m() { } }
->C : Symbol(C, Decl(objectSpread.ts, 42, 42))
->p : Symbol(C.p, Decl(objectSpread.ts, 45, 9))
->m : Symbol(C.m, Decl(objectSpread.ts, 45, 16))
+>C : Symbol(C, Decl(objectSpread.ts, 44, 29))
+>p : Symbol(C.p, Decl(objectSpread.ts, 47, 9))
+>m : Symbol(C.m, Decl(objectSpread.ts, 47, 16))
 
 let c: C = new C()
->c : Symbol(c, Decl(objectSpread.ts, 46, 3))
->C : Symbol(C, Decl(objectSpread.ts, 42, 42))
->C : Symbol(C, Decl(objectSpread.ts, 42, 42))
+>c : Symbol(c, Decl(objectSpread.ts, 48, 3))
+>C : Symbol(C, Decl(objectSpread.ts, 44, 29))
+>C : Symbol(C, Decl(objectSpread.ts, 44, 29))
 
 let spreadC: { p: number } = { ...c }
->spreadC : Symbol(spreadC, Decl(objectSpread.ts, 47, 3))
->p : Symbol(p, Decl(objectSpread.ts, 47, 14))
+>spreadC : Symbol(spreadC, Decl(objectSpread.ts, 49, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 49, 14))
 
 // own methods are enumerable
 let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } };
->cplus : Symbol(cplus, Decl(objectSpread.ts, 50, 3))
->p : Symbol(p, Decl(objectSpread.ts, 50, 12))
->plus : Symbol(plus, Decl(objectSpread.ts, 50, 23))
->plus : Symbol(plus, Decl(objectSpread.ts, 50, 48))
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 52, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 52, 12))
+>plus : Symbol(plus, Decl(objectSpread.ts, 52, 23))
+>plus : Symbol(plus, Decl(objectSpread.ts, 52, 48))
 
 cplus.plus();
->cplus.plus : Symbol(plus, Decl(objectSpread.ts, 50, 23))
->cplus : Symbol(cplus, Decl(objectSpread.ts, 50, 3))
->plus : Symbol(plus, Decl(objectSpread.ts, 50, 23))
+>cplus.plus : Symbol(plus, Decl(objectSpread.ts, 52, 23))
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 52, 3))
+>plus : Symbol(plus, Decl(objectSpread.ts, 52, 23))
 
 // new field's type conflicting with existing field is OK
 let changeTypeAfter: { a: string, b: string } =
->changeTypeAfter : Symbol(changeTypeAfter, Decl(objectSpread.ts, 54, 3))
->a : Symbol(a, Decl(objectSpread.ts, 54, 22))
->b : Symbol(b, Decl(objectSpread.ts, 54, 33))
+>changeTypeAfter : Symbol(changeTypeAfter, Decl(objectSpread.ts, 56, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 56, 22))
+>b : Symbol(b, Decl(objectSpread.ts, 56, 33))
 
     { ...o, a: 'wrong type?' }
->a : Symbol(a, Decl(objectSpread.ts, 55, 11))
+>a : Symbol(a, Decl(objectSpread.ts, 57, 11))
 
 let changeTypeBefore: { a: number, b: string } =
->changeTypeBefore : Symbol(changeTypeBefore, Decl(objectSpread.ts, 56, 3))
->a : Symbol(a, Decl(objectSpread.ts, 56, 23))
->b : Symbol(b, Decl(objectSpread.ts, 56, 34))
+>changeTypeBefore : Symbol(changeTypeBefore, Decl(objectSpread.ts, 58, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 58, 23))
+>b : Symbol(b, Decl(objectSpread.ts, 58, 34))
 
     { a: 'wrong type?', ...o };
->a : Symbol(a, Decl(objectSpread.ts, 57, 5))
+>a : Symbol(a, Decl(objectSpread.ts, 59, 5))
 
 let changeTypeBoth: { a: string, b: number } =
->changeTypeBoth : Symbol(changeTypeBoth, Decl(objectSpread.ts, 58, 3))
->a : Symbol(a, Decl(objectSpread.ts, 58, 21))
->b : Symbol(b, Decl(objectSpread.ts, 58, 32))
+>changeTypeBoth : Symbol(changeTypeBoth, Decl(objectSpread.ts, 60, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 60, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 60, 32))
 
     { ...o, ...swap };
 
 // optional
 let definiteBoolean: { sn: boolean };
->definiteBoolean : Symbol(definiteBoolean, Decl(objectSpread.ts, 62, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 62, 22))
+>definiteBoolean : Symbol(definiteBoolean, Decl(objectSpread.ts, 64, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 64, 22))
 
 let definiteString: { sn: string };
->definiteString : Symbol(definiteString, Decl(objectSpread.ts, 63, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 63, 21))
+>definiteString : Symbol(definiteString, Decl(objectSpread.ts, 65, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 65, 21))
 
 let optionalString: { sn?: string };
->optionalString : Symbol(optionalString, Decl(objectSpread.ts, 64, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 64, 21))
+>optionalString : Symbol(optionalString, Decl(objectSpread.ts, 66, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 66, 21))
 
 let optionalNumber: { sn?: number };
->optionalNumber : Symbol(optionalNumber, Decl(objectSpread.ts, 65, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 65, 21))
+>optionalNumber : Symbol(optionalNumber, Decl(objectSpread.ts, 67, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 67, 21))
 
 let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
->optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpread.ts, 66, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 66, 25))
+>optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpread.ts, 68, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 68, 25))
 
 let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
->optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpread.ts, 67, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 67, 30))
+>optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpread.ts, 69, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 69, 30))
 
 let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
->allOptional : Symbol(allOptional, Decl(objectSpread.ts, 68, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 68, 18))
+>allOptional : Symbol(allOptional, Decl(objectSpread.ts, 70, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 70, 18))
 
 // computed property
 let computedFirst: { a: number, b: string, "before everything": number } =
->computedFirst : Symbol(computedFirst, Decl(objectSpread.ts, 71, 3))
->a : Symbol(a, Decl(objectSpread.ts, 71, 20))
->b : Symbol(b, Decl(objectSpread.ts, 71, 31))
+>computedFirst : Symbol(computedFirst, Decl(objectSpread.ts, 73, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 73, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 73, 31))
 
     { ['before everything']: 12, ...o, b: 'yes' }
->'before everything' : Symbol(['before everything'], Decl(objectSpread.ts, 72, 5))
->b : Symbol(b, Decl(objectSpread.ts, 72, 38))
+>'before everything' : Symbol(['before everything'], Decl(objectSpread.ts, 74, 5))
+>b : Symbol(b, Decl(objectSpread.ts, 74, 38))
 
 let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
->computedMiddle : Symbol(computedMiddle, Decl(objectSpread.ts, 73, 3))
->a : Symbol(a, Decl(objectSpread.ts, 73, 21))
->b : Symbol(b, Decl(objectSpread.ts, 73, 32))
->c : Symbol(c, Decl(objectSpread.ts, 73, 43))
+>computedMiddle : Symbol(computedMiddle, Decl(objectSpread.ts, 75, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 75, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 75, 32))
+>c : Symbol(c, Decl(objectSpread.ts, 75, 43))
 
     { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
->'in the middle' : Symbol(['in the middle'], Decl(objectSpread.ts, 74, 11))
->b : Symbol(b, Decl(objectSpread.ts, 74, 34))
+>'in the middle' : Symbol(['in the middle'], Decl(objectSpread.ts, 76, 11))
+>b : Symbol(b, Decl(objectSpread.ts, 76, 34))
 
 let computedAfter: { a: number, b: string, "at the end": number } =
->computedAfter : Symbol(computedAfter, Decl(objectSpread.ts, 75, 3))
->a : Symbol(a, Decl(objectSpread.ts, 75, 20))
->b : Symbol(b, Decl(objectSpread.ts, 75, 31))
+>computedAfter : Symbol(computedAfter, Decl(objectSpread.ts, 77, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 77, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 77, 31))
 
     { ...o, b: 'yeah', ['at the end']: 14 }
->b : Symbol(b, Decl(objectSpread.ts, 76, 11))
->'at the end' : Symbol(['at the end'], Decl(objectSpread.ts, 76, 22))
+>b : Symbol(b, Decl(objectSpread.ts, 78, 11))
+>'at the end' : Symbol(['at the end'], Decl(objectSpread.ts, 78, 22))
 
 // shortcut syntax
 let a = 12;
->a : Symbol(a, Decl(objectSpread.ts, 78, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 80, 3))
 
 let shortCutted: { a: number, b: string } = { ...o, a }
->shortCutted : Symbol(shortCutted, Decl(objectSpread.ts, 79, 3))
->a : Symbol(a, Decl(objectSpread.ts, 79, 18))
->b : Symbol(b, Decl(objectSpread.ts, 79, 29))
->a : Symbol(a, Decl(objectSpread.ts, 79, 51))
+>shortCutted : Symbol(shortCutted, Decl(objectSpread.ts, 81, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 81, 18))
+>b : Symbol(b, Decl(objectSpread.ts, 81, 29))
+>a : Symbol(a, Decl(objectSpread.ts, 81, 51))
 
 // generics
 function f<T, U>(t: T, u: U): { id: string, ...T, ...U } {
->f : Symbol(f, Decl(objectSpread.ts, 79, 55))
->T : Symbol(T, Decl(objectSpread.ts, 82, 11))
->U : Symbol(U, Decl(objectSpread.ts, 82, 13))
->t : Symbol(t, Decl(objectSpread.ts, 82, 17))
->T : Symbol(T, Decl(objectSpread.ts, 82, 11))
->u : Symbol(u, Decl(objectSpread.ts, 82, 22))
->U : Symbol(U, Decl(objectSpread.ts, 82, 13))
->id : Symbol(id, Decl(objectSpread.ts, 82, 31))
->T : Symbol(T, Decl(objectSpread.ts, 82, 11))
->U : Symbol(U, Decl(objectSpread.ts, 82, 13))
+>f : Symbol(f, Decl(objectSpread.ts, 81, 55))
+>T : Symbol(T, Decl(objectSpread.ts, 84, 11))
+>U : Symbol(U, Decl(objectSpread.ts, 84, 13))
+>t : Symbol(t, Decl(objectSpread.ts, 84, 17))
+>T : Symbol(T, Decl(objectSpread.ts, 84, 11))
+>u : Symbol(u, Decl(objectSpread.ts, 84, 22))
+>U : Symbol(U, Decl(objectSpread.ts, 84, 13))
+>id : Symbol(id, Decl(objectSpread.ts, 84, 31))
+>T : Symbol(T, Decl(objectSpread.ts, 84, 11))
+>U : Symbol(U, Decl(objectSpread.ts, 84, 13))
 
     return { id: 'id', ...t, ...u };
->id : Symbol(id, Decl(objectSpread.ts, 83, 12))
+>id : Symbol(id, Decl(objectSpread.ts, 85, 12))
 }
 let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
->exclusive : Symbol(exclusive, Decl(objectSpread.ts, 85, 3))
->id : Symbol(id, Decl(objectSpread.ts, 85, 16))
->a : Symbol(a, Decl(objectSpread.ts, 85, 28))
->b : Symbol(b, Decl(objectSpread.ts, 85, 39))
->c : Symbol(c, Decl(objectSpread.ts, 85, 50))
->d : Symbol(d, Decl(objectSpread.ts, 85, 61))
+>exclusive : Symbol(exclusive, Decl(objectSpread.ts, 87, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 87, 16))
+>a : Symbol(a, Decl(objectSpread.ts, 87, 28))
+>b : Symbol(b, Decl(objectSpread.ts, 87, 39))
+>c : Symbol(c, Decl(objectSpread.ts, 87, 50))
+>d : Symbol(d, Decl(objectSpread.ts, 87, 61))
 
     f({ a: 1, b: 'yes' }, { c: 'no', d: false })
->f : Symbol(f, Decl(objectSpread.ts, 79, 55))
->a : Symbol(a, Decl(objectSpread.ts, 86, 7))
->b : Symbol(b, Decl(objectSpread.ts, 86, 13))
->c : Symbol(c, Decl(objectSpread.ts, 86, 27))
->d : Symbol(d, Decl(objectSpread.ts, 86, 36))
+>f : Symbol(f, Decl(objectSpread.ts, 81, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 88, 7))
+>b : Symbol(b, Decl(objectSpread.ts, 88, 13))
+>c : Symbol(c, Decl(objectSpread.ts, 88, 27))
+>d : Symbol(d, Decl(objectSpread.ts, 88, 36))
 
 let overlap: { id: string, a: number, b: string } =
->overlap : Symbol(overlap, Decl(objectSpread.ts, 87, 3))
->id : Symbol(id, Decl(objectSpread.ts, 87, 14))
->a : Symbol(a, Decl(objectSpread.ts, 87, 26))
->b : Symbol(b, Decl(objectSpread.ts, 87, 37))
+>overlap : Symbol(overlap, Decl(objectSpread.ts, 89, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 89, 14))
+>a : Symbol(a, Decl(objectSpread.ts, 89, 26))
+>b : Symbol(b, Decl(objectSpread.ts, 89, 37))
 
     f({ a: 1 }, { a: 2, b: 'extra' })
->f : Symbol(f, Decl(objectSpread.ts, 79, 55))
->a : Symbol(a, Decl(objectSpread.ts, 88, 7))
->a : Symbol(a, Decl(objectSpread.ts, 88, 17))
->b : Symbol(b, Decl(objectSpread.ts, 88, 23))
+>f : Symbol(f, Decl(objectSpread.ts, 81, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 90, 7))
+>a : Symbol(a, Decl(objectSpread.ts, 90, 17))
+>b : Symbol(b, Decl(objectSpread.ts, 90, 23))
 
 let overlapConflict: { id:string, a: string } =
->overlapConflict : Symbol(overlapConflict, Decl(objectSpread.ts, 89, 3))
->id : Symbol(id, Decl(objectSpread.ts, 89, 22))
->a : Symbol(a, Decl(objectSpread.ts, 89, 33))
+>overlapConflict : Symbol(overlapConflict, Decl(objectSpread.ts, 91, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 91, 22))
+>a : Symbol(a, Decl(objectSpread.ts, 91, 33))
 
     f({ a: 1 }, { a: 'mismatch' })
->f : Symbol(f, Decl(objectSpread.ts, 79, 55))
->a : Symbol(a, Decl(objectSpread.ts, 90, 7))
->a : Symbol(a, Decl(objectSpread.ts, 90, 17))
+>f : Symbol(f, Decl(objectSpread.ts, 81, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 92, 7))
+>a : Symbol(a, Decl(objectSpread.ts, 92, 17))
 
 let overwriteId: { id: boolean, a: number, c: number, d: string } =
->overwriteId : Symbol(overwriteId, Decl(objectSpread.ts, 91, 3))
->id : Symbol(id, Decl(objectSpread.ts, 91, 18))
->a : Symbol(a, Decl(objectSpread.ts, 91, 31))
->c : Symbol(c, Decl(objectSpread.ts, 91, 42))
->d : Symbol(d, Decl(objectSpread.ts, 91, 53))
+>overwriteId : Symbol(overwriteId, Decl(objectSpread.ts, 93, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 93, 18))
+>a : Symbol(a, Decl(objectSpread.ts, 93, 31))
+>c : Symbol(c, Decl(objectSpread.ts, 93, 42))
+>d : Symbol(d, Decl(objectSpread.ts, 93, 53))
 
     f({ a: 1, id: true }, { c: 1, d: 'no' })
->f : Symbol(f, Decl(objectSpread.ts, 79, 55))
->a : Symbol(a, Decl(objectSpread.ts, 92, 7))
->id : Symbol(id, Decl(objectSpread.ts, 92, 13))
->c : Symbol(c, Decl(objectSpread.ts, 92, 27))
->d : Symbol(d, Decl(objectSpread.ts, 92, 33))
+>f : Symbol(f, Decl(objectSpread.ts, 81, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 94, 7))
+>id : Symbol(id, Decl(objectSpread.ts, 94, 13))
+>c : Symbol(c, Decl(objectSpread.ts, 94, 27))
+>d : Symbol(d, Decl(objectSpread.ts, 94, 33))
 
 class D { m() { }; q = 2; }
->D : Symbol(D, Decl(objectSpread.ts, 92, 44))
->m : Symbol(D.m, Decl(objectSpread.ts, 94, 9))
->q : Symbol(D.q, Decl(objectSpread.ts, 94, 18))
+>D : Symbol(D, Decl(objectSpread.ts, 94, 44))
+>m : Symbol(D.m, Decl(objectSpread.ts, 96, 9))
+>q : Symbol(D.q, Decl(objectSpread.ts, 96, 18))
 
 let classesAreWrong: { id: string, ...C, ...D } =
->classesAreWrong : Symbol(classesAreWrong, Decl(objectSpread.ts, 95, 3))
->id : Symbol(id, Decl(objectSpread.ts, 95, 22))
->C : Symbol(C, Decl(objectSpread.ts, 42, 42))
->D : Symbol(D, Decl(objectSpread.ts, 92, 44))
+>classesAreWrong : Symbol(classesAreWrong, Decl(objectSpread.ts, 97, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 97, 22))
+>C : Symbol(C, Decl(objectSpread.ts, 44, 29))
+>D : Symbol(D, Decl(objectSpread.ts, 94, 44))
 
     f(new C(), new D())
->f : Symbol(f, Decl(objectSpread.ts, 79, 55))
->C : Symbol(C, Decl(objectSpread.ts, 42, 42))
->D : Symbol(D, Decl(objectSpread.ts, 92, 44))
+>f : Symbol(f, Decl(objectSpread.ts, 81, 55))
+>C : Symbol(C, Decl(objectSpread.ts, 44, 29))
+>D : Symbol(D, Decl(objectSpread.ts, 94, 44))
 
diff --git a/tests/baselines/reference/objectSpread.types b/tests/baselines/reference/objectSpread.types
index 2b13af1d3d6e7..efab098fd6e22 100644
--- a/tests/baselines/reference/objectSpread.types
+++ b/tests/baselines/reference/objectSpread.types
@@ -223,7 +223,7 @@ getter.a = 12;
 >a : number
 >12 : 12
 
-// null, undefined, functions and primitives result in { }
+// null, undefined, functions and primitives besides string result in { }
 let spreadNull = { ...null };
 >spreadNull : {}
 >{ ...null } : {}
@@ -238,10 +238,6 @@ let spreadNum = { ...12 };
 >spreadNum : {}
 >{ ...12 } : {}
 
-let spreadStr = { ...'foo' };
->spreadStr : {}
->{ ...'foo' } : {}
-
 let spreadBool = { ...false };
 >spreadBool : {}
 >{ ...false } : {}
@@ -253,6 +249,11 @@ let spreadFunc = { ...(function () { }) };
 >(function () { }) : () => void
 >function () { } : () => void
 
+// strings get a numeric indexer: [n: number]: string
+let spreadStr = { ...'foo' };
+>spreadStr : { [x: number]: string; }
+>{ ...'foo' } : { [x: number]: string; }
+
 // methods are not enumerable
 class C { p = 1; m() { } }
 >C : C
diff --git a/tests/baselines/reference/objectSpreadNegative.errors.txt b/tests/baselines/reference/objectSpreadNegative.errors.txt
index 84fb1cc4a76c1..b79354c4a9487 100644
--- a/tests/baselines/reference/objectSpreadNegative.errors.txt
+++ b/tests/baselines/reference/objectSpreadNegative.errors.txt
@@ -11,8 +11,8 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(30,12): error TS233
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(32,17): error TS2339: Property 'undefined' does not exist on type '{}'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(36,11): error TS2339: Property 'toFixed' does not exist on type '{}'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(38,11): error TS2339: Property 'toFixed' does not exist on type '{}'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(40,11): error TS2339: Property 'length' does not exist on type '{}'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(41,11): error TS2339: Property 'charAt' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(40,11): error TS2339: Property 'length' does not exist on type '{ [x: number]: string; }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(41,11): error TS2339: Property 'charAt' does not exist on type '{ [x: number]: string; }'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(45,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{}' has no compatible call signatures.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(49,12): error TS2339: Property 'b' does not exist on type '{}'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(55,9): error TS2339: Property 'm' does not exist on type '{ p: number; }'.
@@ -86,10 +86,10 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(63,12): error TS232
     let spreadStr = { ...'foo' };
     spreadStr.length; // error, no 'length'
               ~~~~~~
-!!! error TS2339: Property 'length' does not exist on type '{}'.
+!!! error TS2339: Property 'length' does not exist on type '{ [x: number]: string; }'.
     spreadStr.charAt(1); // error, no methods either
               ~~~~~~
-!!! error TS2339: Property 'charAt' does not exist on type '{}'.
+!!! error TS2339: Property 'charAt' does not exist on type '{ [x: number]: string; }'.
     let spreadBool = { ...true };
     spreadBool.valueOf(); // error, what were you thinking?
     let spreadFunc = { ...function () { } }
diff --git a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
index 9dd9a8d41a1bf..46782aaa1d69d 100644
--- a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
+++ b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
@@ -1,4 +1,4 @@
-lib.d.ts(28,18): error TS2300: Duplicate identifier 'eval'.
+lib.d.ts(32,18): error TS2300: Duplicate identifier 'eval'.
 tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS1100: Invalid use of 'eval' in strict mode.
 tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS2300: Duplicate identifier 'eval'.
 
diff --git a/tests/cases/conformance/types/spread/objectSpread.ts b/tests/cases/conformance/types/spread/objectSpread.ts
index e94775649e701..fc076e79543de 100644
--- a/tests/cases/conformance/types/spread/objectSpread.ts
+++ b/tests/cases/conformance/types/spread/objectSpread.ts
@@ -35,14 +35,16 @@ let getter: { a: number, c: number } =
     { ...op, c: 7 }
 getter.a = 12;
 
-// null, undefined, functions and primitives result in { }
+// null, undefined, functions and primitives besides string result in { }
 let spreadNull = { ...null };
 let spreadUndefind = { ...undefined };
 let spreadNum = { ...12 };
-let spreadStr = { ...'foo' };
 let spreadBool = { ...false };
 let spreadFunc = { ...(function () { }) };
 
+// strings get a numeric indexer: [n: number]: string
+let spreadStr = { ...'foo' };
+
 // methods are not enumerable
 class C { p = 1; m() { } }
 let c: C = new C()

From ab1b2bb2a94ee6a44d4d3e343d5077b39bbb2d98 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 12 Oct 2016 09:20:12 -0700
Subject: [PATCH 043/224] Reset baseline line number to the locally incorrect
 value

---
 .../reference/variableDeclarationInStrictMode1.errors.txt     | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
index 46782aaa1d69d..c47ac71f74869 100644
--- a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
+++ b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
@@ -1,4 +1,4 @@
-lib.d.ts(32,18): error TS2300: Duplicate identifier 'eval'.
+lib.d.ts(28,18): error TS2300: Duplicate identifier 'eval'.
 tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS1100: Invalid use of 'eval' in strict mode.
 tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS2300: Duplicate identifier 'eval'.
 
@@ -9,4 +9,4 @@ tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS2300: Dup
         ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
         ~~~~
-!!! error TS2300: Duplicate identifier 'eval'.
\ No newline at end of file
+!!! error TS2300: Duplicate identifier 'eval'.

From 3a85312dd816de4031fa1aae1ccccb53eca67e46 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 12 Oct 2016 10:11:33 -0700
Subject: [PATCH 044/224] Remove trailing newline from baseline again

---
 .../reference/variableDeclarationInStrictMode1.errors.txt       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
index c47ac71f74869..9dd9a8d41a1bf 100644
--- a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
+++ b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
@@ -9,4 +9,4 @@ tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS2300: Dup
         ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
         ~~~~
-!!! error TS2300: Duplicate identifier 'eval'.
+!!! error TS2300: Duplicate identifier 'eval'.
\ No newline at end of file

From 9b2e6a33cfe0348fc59e89050fa14e911ae3f8ec Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Wed, 12 Oct 2016 10:08:43 -0700
Subject: [PATCH 045/224] Respond to PR comments

---
 src/compiler/commandLineParser.ts | 16 ++++++++++------
 src/compiler/core.ts              |  6 +++---
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 135cec842e03c..8ffae3b8680dc 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -1289,14 +1289,18 @@ namespace ts {
 
     function getWildcardDirectoryFromSpec(spec: string, useCaseSensitiveFileNames: boolean): { key: string, flags: WatchDirectoryFlags } | undefined {
         const match = wildcardDirectoryPattern.exec(spec);
-        return match
-            ? {
+        if (match) {
+            return {
                 key: useCaseSensitiveFileNames ? match[0] : match[0].toLowerCase(),
                 flags: watchRecursivePattern.test(spec) ? WatchDirectoryFlags.Recursive : WatchDirectoryFlags.None
-            }
-            : isImplicitGlob(spec)
-            ? { key: spec, flags: WatchDirectoryFlags.Recursive }
-            : undefined;
+            };
+        }
+        else if (isImplicitGlob(spec)) {
+            return { key: spec, flags: WatchDirectoryFlags.Recursive };
+        }
+        else {
+            return undefined;
+        }
     }
 
     /**
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 81662af91cf83..0164d0f43339a 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -1182,13 +1182,13 @@ namespace ts {
      */
     export function getDirectoryPath(path: Path): Path;
     export function getDirectoryPath(path: string): string;
-    export function getDirectoryPath(path: string): any {
+    export function getDirectoryPath(path: string): string {
         return path.substr(0, Math.max(getRootLength(path), path.lastIndexOf(directorySeparator)));
     }
 
     function getBasename(path: Path): Path;
     function getBasename(path: string): string;
-    function getBasename(path: string): any {
+    function getBasename(path: string): string {
         return path.substr(Math.max(getRootLength(path), path.lastIndexOf(directorySeparator)));
     }
 
@@ -1519,7 +1519,7 @@ namespace ts {
     }
 
     /**
-     * An "includes" path "foo" is implicitly a glob "foo\**\*" (replace \ with /) if its last component has no extension,
+     * An "includes" path "foo" is implicitly a glob "foo/** /*" (without the space) if its last component has no extension,
      * and does not contain any glob characters itself.
      */
     export function isImplicitGlob(lastPathComponent: string): boolean {

From dceebcdc47d8f3cec9c05735a3df6f5882fb9743 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 12 Oct 2016 11:36:40 -0700
Subject: [PATCH 046/224] Refactor getTypeFromTypeLiteral, from PR comments

---
 src/compiler/checker.ts | 110 ++++++++++++++++++++--------------------
 1 file changed, 56 insertions(+), 54 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index bfd6d78e89164..13de95485c8ce 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5710,67 +5710,69 @@ namespace ts {
         function getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node: Node, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
             const links = getNodeLinks(node);
             if (!links.resolvedType) {
-                const isSpread = (node.kind === SyntaxKind.TypeLiteral &&
-                                  find((node as TypeLiteralNode).members, elt => elt.kind === SyntaxKind.SpreadTypeElement));
-                let type: ObjectType;
-                if (isSpread) {
-                    let members: Map<Symbol>;
-                    let stringIndexInfo: IndexInfo;
-                    let numberIndexInfo: IndexInfo;
-                    const spreads: Type[] = [];
-                    for (const member of (node as TypeLiteralNode).members) {
-                        if (member.kind === SyntaxKind.SpreadTypeElement) {
-                            if (members) {
-                                spreads.push(createAnonymousType(node.symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo));
-                                members = undefined;
-                                stringIndexInfo = undefined;
-                                numberIndexInfo = undefined;
-                            }
-                            spreads.push(getTypeFromTypeNode((member as SpreadTypeElement).type));
-                        }
-                        else if (member.kind === SyntaxKind.IndexSignature) {
-                            const index = member as IndexSignatureDeclaration;
-                            if (index.parameters.length === 1) {
-                                const parameter = index.parameters[0];
-                                if (parameter && parameter.type) {
-                                    const indexInfo = createIndexInfo(index.type ? getTypeFromTypeNode(index.type) : anyType,
-                                                                      (getModifierFlags(index) & ModifierFlags.Readonly) !== 0, index);
-                                    if (parameter.type.kind === SyntaxKind.StringKeyword) {
-                                        stringIndexInfo = indexInfo;
-                                    }
-                                    else {
-                                        numberIndexInfo = indexInfo;
-                                    }
-                                }
+                const hasSpread = (node.kind === SyntaxKind.TypeLiteral &&
+                                   find((node as TypeLiteralNode).members, elt => elt.kind === SyntaxKind.SpreadTypeElement));
+                if (hasSpread) {
+                    return getTypeFromSpreadTypeLiteral(node, aliasSymbol, aliasTypeArguments);
+                }
+
+                let type = createObjectType(TypeFlags.Anonymous, node.symbol);
+                type.aliasSymbol = aliasSymbol;
+                type.aliasTypeArguments = aliasTypeArguments;
+                links.resolvedType = type;
+            }
+            return links.resolvedType;
+        }
+
+        function getTypeFromSpreadTypeLiteral(node: Node, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
+            let members: Map<Symbol>;
+            let stringIndexInfo: IndexInfo;
+            let numberIndexInfo: IndexInfo;
+            const spreads: Type[] = [];
+            for (const member of (node as TypeLiteralNode).members) {
+                if (member.kind === SyntaxKind.SpreadTypeElement) {
+                    if (members) {
+                        spreads.push(createAnonymousType(node.symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo));
+                        members = undefined;
+                        stringIndexInfo = undefined;
+                        numberIndexInfo = undefined;
+                    }
+                    spreads.push(getTypeFromTypeNode((member as SpreadTypeElement).type));
+                }
+                else if (member.kind === SyntaxKind.IndexSignature) {
+                    const index = member as IndexSignatureDeclaration;
+                    if (index.parameters.length === 1) {
+                        const parameter = index.parameters[0];
+                        if (parameter && parameter.type) {
+                            const indexInfo = createIndexInfo(index.type ? getTypeFromTypeNode(index.type) : anyType,
+                                                              (getModifierFlags(index) & ModifierFlags.Readonly) !== 0, index);
+                            if (parameter.type.kind === SyntaxKind.StringKeyword) {
+                                stringIndexInfo = indexInfo;
                             }
-                        }
-                        else if (member.kind !== SyntaxKind.CallSignature && member.kind !== SyntaxKind.ConstructSignature) {
-                            // note that spread types don't include call and construct signatures
-                            const flags = SymbolFlags.Property | SymbolFlags.Transient | (member.questionToken ? SymbolFlags.Optional : 0);
-                            const text = getTextOfPropertyName(member.name);
-                            const symbol = <TransientSymbol>createSymbol(flags, text);
-                            symbol.declarations = [member];
-                            symbol.valueDeclaration = member;
-                            symbol.type = getTypeFromTypeNodeNoAlias((member as IndexSignatureDeclaration | PropertySignature | MethodSignature).type);
-                            if (!members) {
-                                members = createMap<Symbol>();
+                            else {
+                                numberIndexInfo = indexInfo;
                             }
-                            members[symbol.name] = symbol;
                         }
                     }
-                    if (members || stringIndexInfo || numberIndexInfo) {
-                        spreads.push(createAnonymousType(node.symbol, members || emptySymbols, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo));
-                    }
-                    return getSpreadType(spreads, node.symbol, aliasSymbol, aliasTypeArguments);
                 }
-                else {
-                    type = createObjectType(TypeFlags.Anonymous, node.symbol);
+                else if (member.kind !== SyntaxKind.CallSignature && member.kind !== SyntaxKind.ConstructSignature) {
+                    // note that spread types don't include call and construct signatures
+                    const flags = SymbolFlags.Property | SymbolFlags.Transient | (member.questionToken ? SymbolFlags.Optional : 0);
+                    const text = getTextOfPropertyName(member.name);
+                    const symbol = <TransientSymbol>createSymbol(flags, text);
+                    symbol.declarations = [member];
+                    symbol.valueDeclaration = member;
+                    symbol.type = getTypeFromTypeNodeNoAlias((member as IndexSignatureDeclaration | PropertySignature | MethodSignature).type);
+                    if (!members) {
+                        members = createMap<Symbol>();
+                    }
+                    members[symbol.name] = symbol;
                 }
-                type.aliasSymbol = aliasSymbol;
-                type.aliasTypeArguments = aliasTypeArguments;
-                links.resolvedType = type;
             }
-            return links.resolvedType;
+            if (members || stringIndexInfo || numberIndexInfo) {
+                spreads.push(createAnonymousType(node.symbol, members || emptySymbols, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo));
+            }
+            return getSpreadType(spreads, node.symbol, aliasSymbol, aliasTypeArguments);
         }
 
         function getSpreadType(types: Type[], symbol: Symbol, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {

From ce84cee0f26192eed2aac3c405b06514fd7485a1 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 12 Oct 2016 11:53:54 -0700
Subject: [PATCH 047/224] Fix lint

---
 src/compiler/checker.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 13de95485c8ce..9a30fe435ae13 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5716,7 +5716,7 @@ namespace ts {
                     return getTypeFromSpreadTypeLiteral(node, aliasSymbol, aliasTypeArguments);
                 }
 
-                let type = createObjectType(TypeFlags.Anonymous, node.symbol);
+                const type = createObjectType(TypeFlags.Anonymous, node.symbol);
                 type.aliasSymbol = aliasSymbol;
                 type.aliasTypeArguments = aliasTypeArguments;
                 links.resolvedType = type;

From 00ebf59b500d064524af5ddfef87b6c45b53e655 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 13 Oct 2016 16:26:44 -0700
Subject: [PATCH 048/224] Use same literal comparison rules for switch/===

switch was missing the rule for converting literal types to the literal
base type if needed.
---
 src/compiler/checker.ts | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 30a0bbd2042c8..6df09cca70493 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -16584,7 +16584,7 @@ namespace ts {
             let firstDefaultClause: CaseOrDefaultClause;
             let hasDuplicateDefaultClause = false;
 
-            const expressionType = checkExpression(node.expression);
+            let expressionType = checkExpression(node.expression);
             forEach(node.caseBlock.clauses, clause => {
                 // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
                 if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -16605,7 +16605,13 @@ namespace ts {
                     // TypeScript 1.0 spec (April 2014): 5.9
                     // In a 'switch' statement, each 'case' expression must be of a type that is comparable
                     // to or from the type of the 'switch' expression.
-                    const caseType = checkExpression(caseClause.expression);
+                    let caseType = checkExpression(caseClause.expression);
+                    const expressionIsLiteral = isLiteralType(expressionType);
+                    const caseIsLiteral = isLiteralType(caseType);
+                    if (!expressionIsLiteral || !caseIsLiteral) {
+                        expressionType = expressionIsLiteral ? getBaseTypeOfLiteralType(expressionType) : expressionType;
+                        caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
+                    }
                     if (!isTypeEqualityComparableTo(expressionType, caseType)) {
                         // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
                         checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);

From 982abc29442fc145e9364aa7fad510c15f1008ac Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 13 Oct 2016 16:29:35 -0700
Subject: [PATCH 049/224] Add switch comparability test and update baselines

---
 .../switchAssignmentCompat.errors.txt         |  4 +--
 .../switchCaseCircularRefeference.errors.txt  | 10 +++----
 ...itchCasesExpressionTypeMismatch.errors.txt | 17 +++++------
 .../switchComparableCompatForBrands.js        | 29 +++++++++++++++++++
 .../switchComparableCompatForBrands.symbols   | 22 ++++++++++++++
 .../switchComparableCompatForBrands.types     | 26 +++++++++++++++++
 .../switchComparableCompatForBrands.ts        | 13 +++++++++
 7 files changed, 103 insertions(+), 18 deletions(-)
 create mode 100644 tests/baselines/reference/switchComparableCompatForBrands.js
 create mode 100644 tests/baselines/reference/switchComparableCompatForBrands.symbols
 create mode 100644 tests/baselines/reference/switchComparableCompatForBrands.types
 create mode 100644 tests/cases/compiler/switchComparableCompatForBrands.ts

diff --git a/tests/baselines/reference/switchAssignmentCompat.errors.txt b/tests/baselines/reference/switchAssignmentCompat.errors.txt
index 46c89fa5b52d2..747a1035b6846 100644
--- a/tests/baselines/reference/switchAssignmentCompat.errors.txt
+++ b/tests/baselines/reference/switchAssignmentCompat.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 
 
 ==== tests/cases/compiler/switchAssignmentCompat.ts (1 errors) ====
@@ -7,6 +7,6 @@ tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof
     switch (0) {
         case Foo: break; // Error expected
              ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
     }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/switchCaseCircularRefeference.errors.txt b/tests/baselines/reference/switchCaseCircularRefeference.errors.txt
index 9ee571de468ce..bc576f8e723b8 100644
--- a/tests/baselines/reference/switchCaseCircularRefeference.errors.txt
+++ b/tests/baselines/reference/switchCaseCircularRefeference.errors.txt
@@ -1,6 +1,5 @@
-tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-  Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-    Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+  Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
 
 
 ==== tests/cases/compiler/switchCaseCircularRefeference.ts (1 errors) ====
@@ -10,9 +9,8 @@ tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type
         switch (x.a) {
         case x:
              ~
-!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678:   Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678:     Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+!!! error TS2678:   Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
             break;
         }
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt b/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt
index 3ea12e2460f65..26d39efef48ec 100644
--- a/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt
+++ b/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt
@@ -1,25 +1,22 @@
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type '"sss"' is not comparable to type '0'.
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(6,10): error TS2678: Type '123' is not comparable to type '0'.
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'true' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type 'string' is not comparable to type 'number'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'boolean' is not comparable to type 'number'.
 
 
-==== tests/cases/compiler/switchCasesExpressionTypeMismatch.ts (4 errors) ====
+==== tests/cases/compiler/switchCasesExpressionTypeMismatch.ts (3 errors) ====
     class Foo { }
     
     switch (0) {
         case Foo: break;    // Error
              ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
         case "sss": break;  // Error
              ~~~~~
-!!! error TS2678: Type '"sss"' is not comparable to type '0'.
+!!! error TS2678: Type 'string' is not comparable to type 'number'.
         case 123: break;    // No Error
-             ~~~
-!!! error TS2678: Type '123' is not comparable to type '0'.
         case true: break;   // Error
              ~~~~
-!!! error TS2678: Type 'true' is not comparable to type '0'.
+!!! error TS2678: Type 'boolean' is not comparable to type 'number'.
     }
     
     var s: any = 0;
diff --git a/tests/baselines/reference/switchComparableCompatForBrands.js b/tests/baselines/reference/switchComparableCompatForBrands.js
new file mode 100644
index 0000000000000..316edfc9c31b1
--- /dev/null
+++ b/tests/baselines/reference/switchComparableCompatForBrands.js
@@ -0,0 +1,29 @@
+//// [switchComparableCompatForBrands.ts]
+class MyBrand
+{
+    private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+    switch(strInput)
+    {
+        case "a":
+        return 1;
+    }
+    return 0;
+}
+
+
+//// [switchComparableCompatForBrands.js]
+var MyBrand = (function () {
+    function MyBrand() {
+    }
+    return MyBrand;
+}());
+function test(strInput) {
+    switch (strInput) {
+        case "a":
+            return 1;
+    }
+    return 0;
+}
diff --git a/tests/baselines/reference/switchComparableCompatForBrands.symbols b/tests/baselines/reference/switchComparableCompatForBrands.symbols
new file mode 100644
index 0000000000000..adf6a5174adf3
--- /dev/null
+++ b/tests/baselines/reference/switchComparableCompatForBrands.symbols
@@ -0,0 +1,22 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+{
+    private _a: number;
+>_a : Symbol(MyBrand._a, Decl(switchComparableCompatForBrands.ts, 1, 1))
+}
+
+function test(strInput: string & MyBrand) {
+>test : Symbol(test, Decl(switchComparableCompatForBrands.ts, 3, 1))
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+>MyBrand : Symbol(MyBrand, Decl(switchComparableCompatForBrands.ts, 0, 0))
+
+    switch(strInput)
+>strInput : Symbol(strInput, Decl(switchComparableCompatForBrands.ts, 5, 14))
+    {
+        case "a":
+        return 1;
+    }
+    return 0;
+}
+
diff --git a/tests/baselines/reference/switchComparableCompatForBrands.types b/tests/baselines/reference/switchComparableCompatForBrands.types
new file mode 100644
index 0000000000000..5e479ee29dc2e
--- /dev/null
+++ b/tests/baselines/reference/switchComparableCompatForBrands.types
@@ -0,0 +1,26 @@
+=== tests/cases/compiler/switchComparableCompatForBrands.ts ===
+class MyBrand
+>MyBrand : MyBrand
+{
+    private _a: number;
+>_a : number
+}
+
+function test(strInput: string & MyBrand) {
+>test : (strInput: string & MyBrand) => 1 | 0
+>strInput : string & MyBrand
+>MyBrand : MyBrand
+
+    switch(strInput)
+>strInput : string & MyBrand
+    {
+        case "a":
+>"a" : "a"
+
+        return 1;
+>1 : 1
+    }
+    return 0;
+>0 : 0
+}
+
diff --git a/tests/cases/compiler/switchComparableCompatForBrands.ts b/tests/cases/compiler/switchComparableCompatForBrands.ts
new file mode 100644
index 0000000000000..4b90db40e1db8
--- /dev/null
+++ b/tests/cases/compiler/switchComparableCompatForBrands.ts
@@ -0,0 +1,13 @@
+class MyBrand
+{
+    private _a: number;
+}
+
+function test(strInput: string & MyBrand) {
+    switch(strInput)
+    {
+        case "a":
+        return 1;
+    }
+    return 0;
+}

From 0168f67f63c1180caca7c1d3500773e64580d952 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 14 Oct 2016 08:55:01 -0700
Subject: [PATCH 050/224] Push eitherIsNotLiteral check into
 isTypeEqualityComparableTo

Since all callers need this check -- it's how equality is supposed to
work everywhere.
---
 src/compiler/checker.ts | 22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 6df09cca70493..24f71ee41ed13 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -13532,6 +13532,12 @@ namespace ts {
         }
 
         function isTypeEqualityComparableTo(source: Type, target: Type) {
+            const sourceIsLiteral = isLiteralType(source);
+            const targetIsLiteral = isLiteralType(target);
+            if (!sourceIsLiteral || !targetIsLiteral) {
+                source = sourceIsLiteral ? getBaseTypeOfLiteralType(source) : source;
+                target = targetIsLiteral ? getBaseTypeOfLiteralType(target) : target;
+            }
             return (target.flags & TypeFlags.Nullable) !== 0 || isTypeComparableTo(source, target);
         }
 
@@ -13672,12 +13678,6 @@ namespace ts {
                 case SyntaxKind.ExclamationEqualsToken:
                 case SyntaxKind.EqualsEqualsEqualsToken:
                 case SyntaxKind.ExclamationEqualsEqualsToken:
-                    const leftIsLiteral = isLiteralType(leftType);
-                    const rightIsLiteral = isLiteralType(rightType);
-                    if (!leftIsLiteral || !rightIsLiteral) {
-                        leftType = leftIsLiteral ? getBaseTypeOfLiteralType(leftType) : leftType;
-                        rightType = rightIsLiteral ? getBaseTypeOfLiteralType(rightType) : rightType;
-                    }
                     if (!isTypeEqualityComparableTo(leftType, rightType) && !isTypeEqualityComparableTo(rightType, leftType)) {
                         reportOperatorError();
                     }
@@ -16584,7 +16584,7 @@ namespace ts {
             let firstDefaultClause: CaseOrDefaultClause;
             let hasDuplicateDefaultClause = false;
 
-            let expressionType = checkExpression(node.expression);
+            const expressionType = checkExpression(node.expression);
             forEach(node.caseBlock.clauses, clause => {
                 // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
                 if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -16605,13 +16605,7 @@ namespace ts {
                     // TypeScript 1.0 spec (April 2014): 5.9
                     // In a 'switch' statement, each 'case' expression must be of a type that is comparable
                     // to or from the type of the 'switch' expression.
-                    let caseType = checkExpression(caseClause.expression);
-                    const expressionIsLiteral = isLiteralType(expressionType);
-                    const caseIsLiteral = isLiteralType(caseType);
-                    if (!expressionIsLiteral || !caseIsLiteral) {
-                        expressionType = expressionIsLiteral ? getBaseTypeOfLiteralType(expressionType) : expressionType;
-                        caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
-                    }
+                    const caseType = checkExpression(caseClause.expression);
                     if (!isTypeEqualityComparableTo(expressionType, caseType)) {
                         // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
                         checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);

From 83d6abcd9eb829c9ac01376d27741228e09d1ae6 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 14 Oct 2016 08:59:00 -0700
Subject: [PATCH 051/224] Update baselines

There are more literal types in error messages because error reporting
no longer has the advantage of calls to getBaseLiteralType
---
 tests/baselines/reference/expr.errors.txt       |  8 ++++----
 .../for-inStatementsArrayErrors.errors.txt      |  4 ++--
 ...AssertionsInEqualityComparisons02.errors.txt |  4 ++--
 .../reference/switchAssignmentCompat.errors.txt |  4 ++--
 .../switchCaseCircularRefeference.errors.txt    | 10 ++++++----
 ...switchCasesExpressionTypeMismatch.errors.txt | 17 ++++++++++-------
 .../baselines/reference/symbolType9.errors.txt  | 16 ++++++++--------
 7 files changed, 34 insertions(+), 29 deletions(-)

diff --git a/tests/baselines/reference/expr.errors.txt b/tests/baselines/reference/expr.errors.txt
index 23215cac6bae2..52f6f64fef287 100644
--- a/tests/baselines/reference/expr.errors.txt
+++ b/tests/baselines/reference/expr.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/compiler/expr.ts(87,5): error TS2365: Operator '==' cannot be applied to types 'number' and 'string'.
-tests/cases/compiler/expr.ts(88,5): error TS2365: Operator '==' cannot be applied to types 'number' and 'boolean'.
+tests/cases/compiler/expr.ts(88,5): error TS2365: Operator '==' cannot be applied to types 'number' and 'false'.
 tests/cases/compiler/expr.ts(94,5): error TS2365: Operator '==' cannot be applied to types 'string' and 'number'.
-tests/cases/compiler/expr.ts(95,5): error TS2365: Operator '==' cannot be applied to types 'string' and 'boolean'.
+tests/cases/compiler/expr.ts(95,5): error TS2365: Operator '==' cannot be applied to types 'string' and 'false'.
 tests/cases/compiler/expr.ts(98,5): error TS2365: Operator '==' cannot be applied to types 'string' and 'E'.
 tests/cases/compiler/expr.ts(115,5): error TS2365: Operator '==' cannot be applied to types 'E' and 'string'.
 tests/cases/compiler/expr.ts(116,5): error TS2365: Operator '==' cannot be applied to types 'E' and 'false'.
@@ -161,7 +161,7 @@ tests/cases/compiler/expr.ts(242,7): error TS2363: The right-hand side of an ari
 !!! error TS2365: Operator '==' cannot be applied to types 'number' and 'string'.
         n==b;
         ~~~~
-!!! error TS2365: Operator '==' cannot be applied to types 'number' and 'boolean'.
+!!! error TS2365: Operator '==' cannot be applied to types 'number' and 'false'.
         n==i;
         n==n;
         n==e;
@@ -172,7 +172,7 @@ tests/cases/compiler/expr.ts(242,7): error TS2363: The right-hand side of an ari
 !!! error TS2365: Operator '==' cannot be applied to types 'string' and 'number'.
         s==b;
         ~~~~
-!!! error TS2365: Operator '==' cannot be applied to types 'string' and 'boolean'.
+!!! error TS2365: Operator '==' cannot be applied to types 'string' and 'false'.
         s==i;
         s==s;
         s==e;
diff --git a/tests/baselines/reference/for-inStatementsArrayErrors.errors.txt b/tests/baselines/reference/for-inStatementsArrayErrors.errors.txt
index 6886d992bb2e5..e639d8452de21 100644
--- a/tests/baselines/reference/for-inStatementsArrayErrors.errors.txt
+++ b/tests/baselines/reference/for-inStatementsArrayErrors.errors.txt
@@ -1,6 +1,6 @@
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(5,14): error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(6,16): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(7,9): error TS2365: Operator '===' cannot be applied to types 'string' and 'number'.
+tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(7,9): error TS2365: Operator '===' cannot be applied to types 'string' and '1'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(9,16): error TS2339: Property 'unknownProperty' does not exist on type 'string'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(13,10): error TS2403: Subsequent variable declarations must have the same type.  Variable 'i' must be of type 'number', but here has type 'string'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(17,10): error TS2403: Subsequent variable declarations must have the same type.  Variable 'j' must be of type 'any', but here has type 'string'.
@@ -19,7 +19,7 @@ tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
         if (x === 1) {
             ~~~~~~~
-!!! error TS2365: Operator '===' cannot be applied to types 'string' and 'number'.
+!!! error TS2365: Operator '===' cannot be applied to types 'string' and '1'.
         }
         let a3 = x.unknownProperty;
                    ~~~~~~~~~~~~~~~
diff --git a/tests/baselines/reference/stringLiteralsAssertionsInEqualityComparisons02.errors.txt b/tests/baselines/reference/stringLiteralsAssertionsInEqualityComparisons02.errors.txt
index fd92af4e84f63..81adf58dbde90 100644
--- a/tests/baselines/reference/stringLiteralsAssertionsInEqualityComparisons02.errors.txt
+++ b/tests/baselines/reference/stringLiteralsAssertionsInEqualityComparisons02.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/types/literal/stringLiteralsAssertionsInEqualityComparisons02.ts(3,9): error TS2365: Operator '===' cannot be applied to types '"foo"' and '"baz"'.
-tests/cases/conformance/types/literal/stringLiteralsAssertionsInEqualityComparisons02.ts(5,9): error TS2365: Operator '==' cannot be applied to types 'string' and 'number'.
+tests/cases/conformance/types/literal/stringLiteralsAssertionsInEqualityComparisons02.ts(5,9): error TS2365: Operator '==' cannot be applied to types '"foo"' and 'number'.
 tests/cases/conformance/types/literal/stringLiteralsAssertionsInEqualityComparisons02.ts(5,19): error TS2352: Type 'string' cannot be converted to type 'number'.
 
 
@@ -12,7 +12,7 @@ tests/cases/conformance/types/literal/stringLiteralsAssertionsInEqualityComparis
     var b = "foo" !== ("bar" as "foo");
     var c = "foo" == (<number>"bar");
             ~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2365: Operator '==' cannot be applied to types 'string' and 'number'.
+!!! error TS2365: Operator '==' cannot be applied to types '"foo"' and 'number'.
                       ~~~~~~~~~~~~~
 !!! error TS2352: Type 'string' cannot be converted to type 'number'.
     var d = "foo" === ("bar" as EnhancedString);
\ No newline at end of file
diff --git a/tests/baselines/reference/switchAssignmentCompat.errors.txt b/tests/baselines/reference/switchAssignmentCompat.errors.txt
index 747a1035b6846..46c89fa5b52d2 100644
--- a/tests/baselines/reference/switchAssignmentCompat.errors.txt
+++ b/tests/baselines/reference/switchAssignmentCompat.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
+tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
 
 
 ==== tests/cases/compiler/switchAssignmentCompat.ts (1 errors) ====
@@ -7,6 +7,6 @@ tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof
     switch (0) {
         case Foo: break; // Error expected
              ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
     }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/switchCaseCircularRefeference.errors.txt b/tests/baselines/reference/switchCaseCircularRefeference.errors.txt
index bc576f8e723b8..9ee571de468ce 100644
--- a/tests/baselines/reference/switchCaseCircularRefeference.errors.txt
+++ b/tests/baselines/reference/switchCaseCircularRefeference.errors.txt
@@ -1,5 +1,6 @@
-tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
-  Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
+tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
+  Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
+    Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
 
 
 ==== tests/cases/compiler/switchCaseCircularRefeference.ts (1 errors) ====
@@ -9,8 +10,9 @@ tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type
         switch (x.a) {
         case x:
              ~
-!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
-!!! error TS2678:   Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
+!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
+!!! error TS2678:   Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
+!!! error TS2678:     Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
             break;
         }
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt b/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt
index 26d39efef48ec..3ea12e2460f65 100644
--- a/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt
+++ b/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt
@@ -1,22 +1,25 @@
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type 'string' is not comparable to type 'number'.
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'boolean' is not comparable to type 'number'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type '"sss"' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(6,10): error TS2678: Type '123' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'true' is not comparable to type '0'.
 
 
-==== tests/cases/compiler/switchCasesExpressionTypeMismatch.ts (3 errors) ====
+==== tests/cases/compiler/switchCasesExpressionTypeMismatch.ts (4 errors) ====
     class Foo { }
     
     switch (0) {
         case Foo: break;    // Error
              ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
         case "sss": break;  // Error
              ~~~~~
-!!! error TS2678: Type 'string' is not comparable to type 'number'.
+!!! error TS2678: Type '"sss"' is not comparable to type '0'.
         case 123: break;    // No Error
+             ~~~
+!!! error TS2678: Type '123' is not comparable to type '0'.
         case true: break;   // Error
              ~~~~
-!!! error TS2678: Type 'boolean' is not comparable to type 'number'.
+!!! error TS2678: Type 'true' is not comparable to type '0'.
     }
     
     var s: any = 0;
diff --git a/tests/baselines/reference/symbolType9.errors.txt b/tests/baselines/reference/symbolType9.errors.txt
index 5506fdc6f9dac..55a766a379e80 100644
--- a/tests/baselines/reference/symbolType9.errors.txt
+++ b/tests/baselines/reference/symbolType9.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/conformance/es6/Symbols/symbolType9.ts(3,1): error TS2365: Operator '==' cannot be applied to types 'symbol' and 'boolean'.
-tests/cases/conformance/es6/Symbols/symbolType9.ts(5,1): error TS2365: Operator '!=' cannot be applied to types 'number' and 'symbol'.
-tests/cases/conformance/es6/Symbols/symbolType9.ts(7,1): error TS2365: Operator '===' cannot be applied to types 'symbol' and 'number'.
-tests/cases/conformance/es6/Symbols/symbolType9.ts(9,1): error TS2365: Operator '!==' cannot be applied to types 'boolean' and 'symbol'.
+tests/cases/conformance/es6/Symbols/symbolType9.ts(3,1): error TS2365: Operator '==' cannot be applied to types 'symbol' and 'true'.
+tests/cases/conformance/es6/Symbols/symbolType9.ts(5,1): error TS2365: Operator '!=' cannot be applied to types '0' and 'symbol'.
+tests/cases/conformance/es6/Symbols/symbolType9.ts(7,1): error TS2365: Operator '===' cannot be applied to types 'symbol' and '1'.
+tests/cases/conformance/es6/Symbols/symbolType9.ts(9,1): error TS2365: Operator '!==' cannot be applied to types 'false' and 'symbol'.
 
 
 ==== tests/cases/conformance/es6/Symbols/symbolType9.ts (4 errors) ====
@@ -9,16 +9,16 @@ tests/cases/conformance/es6/Symbols/symbolType9.ts(9,1): error TS2365: Operator
     s == s;
     s == true;
     ~~~~~~~~~
-!!! error TS2365: Operator '==' cannot be applied to types 'symbol' and 'boolean'.
+!!! error TS2365: Operator '==' cannot be applied to types 'symbol' and 'true'.
     s != s;
     0 != s;
     ~~~~~~
-!!! error TS2365: Operator '!=' cannot be applied to types 'number' and 'symbol'.
+!!! error TS2365: Operator '!=' cannot be applied to types '0' and 'symbol'.
     s === s;
     s === 1;
     ~~~~~~~
-!!! error TS2365: Operator '===' cannot be applied to types 'symbol' and 'number'.
+!!! error TS2365: Operator '===' cannot be applied to types 'symbol' and '1'.
     s !== s;
     false !== s;
     ~~~~~~~~~~~
-!!! error TS2365: Operator '!==' cannot be applied to types 'boolean' and 'symbol'.
\ No newline at end of file
+!!! error TS2365: Operator '!==' cannot be applied to types 'false' and 'symbol'.
\ No newline at end of file

From e97368bb3f01c1cfa314e7546b1794efa5b095e8 Mon Sep 17 00:00:00 2001
From: Ron Buckton <rbuckton@microsoft.com>
Date: Thu, 13 Oct 2016 17:53:44 -0700
Subject: [PATCH 052/224] Adds ES5 to ES3 transformer for reserved words

---
 Jakefile.js                                   |  13 +-
 src/compiler/transformer.ts                   |   5 +
 src/compiler/transformers/es5.ts              |  83 ++++++++++
 src/compiler/transformers/module/module.ts    |  53 ++-----
 src/compiler/transformers/module/system.ts    |   8 +-
 src/compiler/tsconfig.json                    |   1 +
 src/harness/tsconfig.json                     |   1 +
 src/services/tsconfig.json                    |   1 +
 .../allowSyntheticDefaultImports10.js         |   4 +-
 .../baselines/reference/bluebirdStaticThis.js |   6 +-
 .../reference/classMethodWithKeywordName1.js  |   2 +-
 ...constructorWithIncompleteTypeAnnotation.js |  10 +-
 .../baselines/reference/convertKeywordsYes.js | 144 +++++++++---------
 .../destructuringParameterDeclaration6.js     |   8 +-
 tests/baselines/reference/es6ClassTest5.js    |   2 +-
 .../reference/fatarrowfunctionsErrors.js      |   2 +-
 tests/baselines/reference/keywordField.js     |   6 +-
 .../reference/keywordInJsxIdentifier.js       |   4 +-
 .../reference/nestedClassDeclaration.js       |   2 +-
 ...bjectBindingPatternKeywordIdentifiers01.js |   2 +-
 ...bjectBindingPatternKeywordIdentifiers02.js |   2 +-
 ...bjectBindingPatternKeywordIdentifiers03.js |   2 +-
 ...bjectBindingPatternKeywordIdentifiers04.js |   2 +-
 ...ndPropertiesErrorFromNotUsingIdentifier.js |  12 +-
 ...ctTypesIdentityWithConstructSignatures2.js |   2 +-
 ...ConstructSignaturesDifferingParamCounts.js |   2 +-
 ...nstructSignaturesDifferingByConstraints.js |   2 +-
 ...structSignaturesDifferingByConstraints2.js |   2 +-
 ...structSignaturesDifferingByConstraints3.js |   2 +-
 ...onstructSignaturesDifferingByReturnType.js |   2 +-
 ...nstructSignaturesDifferingByReturnType2.js |   2 +-
 ...tSignaturesDifferingTypeParameterCounts.js |   2 +-
 ...ctSignaturesDifferingTypeParameterNames.js |   2 +-
 ...enericConstructSignaturesOptionalParams.js |   2 +-
 ...nericConstructSignaturesOptionalParams2.js |   2 +-
 ...nericConstructSignaturesOptionalParams3.js |   2 +-
 .../parserErrorRecovery_ObjectLiteral2.js     |   2 +-
 .../parserErrorRecovery_ObjectLiteral3.js     |   2 +-
 .../parserErrorRecovery_ObjectLiteral4.js     |   2 +-
 .../parserErrorRecovery_ObjectLiteral5.js     |   2 +-
 .../parserExportAsFunctionIdentifier.js       |   2 +-
 .../parserKeywordsAsIdentifierName1.js        |   6 +-
 .../parserShorthandPropertyAssignment2.js     |   2 +-
 .../reference/parserSuperExpression3.js       |   2 +-
 .../prototypeOnConstructorFunctions.js        |   2 +-
 tests/baselines/reference/reservedWords.js    |  18 +--
 tests/baselines/reference/reservedWords2.js   |   4 +-
 tests/baselines/reference/super1.js           |   2 +-
 .../reference/tsxReactEmitNesting.js          |  24 +--
 .../reference/typeQueryWithReservedWords.js   |   4 +-
 50 files changed, 267 insertions(+), 206 deletions(-)
 create mode 100644 src/compiler/transformers/es5.ts

diff --git a/Jakefile.js b/Jakefile.js
index 76ac1b19b2c82..c561b72f472b6 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -70,14 +70,15 @@ var compilerSources = [
     "visitor.ts",
     "transformers/destructuring.ts",
     "transformers/ts.ts",
-    "transformers/module/es2015.ts",
-    "transformers/module/system.ts",
-    "transformers/module/module.ts",
     "transformers/jsx.ts",
     "transformers/es2017.ts",
     "transformers/es2016.ts",
     "transformers/es2015.ts",
+    "transformers/es5.ts",
     "transformers/generators.ts",
+    "transformers/module/es2015.ts",
+    "transformers/module/system.ts",
+    "transformers/module/module.ts",
     "transformer.ts",
     "sourcemap.ts",
     "comments.ts",
@@ -105,14 +106,14 @@ var servicesSources = [
     "visitor.ts",
     "transformers/destructuring.ts",
     "transformers/ts.ts",
-    "transformers/module/es2015.ts",
-    "transformers/module/system.ts",
-    "transformers/module/module.ts",
     "transformers/jsx.ts",
     "transformers/es2017.ts",
     "transformers/es2016.ts",
     "transformers/es2015.ts",
     "transformers/generators.ts",
+    "transformers/module/es2015.ts",
+    "transformers/module/system.ts",
+    "transformers/module/module.ts",
     "transformer.ts",
     "sourcemap.ts",
     "comments.ts",
diff --git a/src/compiler/transformer.ts b/src/compiler/transformer.ts
index fc656e08bf9ae..82e1843b70bbe 100644
--- a/src/compiler/transformer.ts
+++ b/src/compiler/transformer.ts
@@ -4,6 +4,7 @@
 /// <reference path="transformers/es2017.ts" />
 /// <reference path="transformers/es2016.ts" />
 /// <reference path="transformers/es2015.ts" />
+/// <reference path="transformers/es5.ts" />
 /// <reference path="transformers/generators.ts" />
 /// <reference path="transformers/module/module.ts" />
 /// <reference path="transformers/module/system.ts" />
@@ -129,6 +130,10 @@ namespace ts {
             transformers.push(transformGenerators);
         }
 
+        if (languageVersion < ScriptTarget.ES5) {
+            transformers.push(transformES5);
+        }
+
         return transformers;
     }
 
diff --git a/src/compiler/transformers/es5.ts b/src/compiler/transformers/es5.ts
new file mode 100644
index 0000000000000..9e5a72c2bad6f
--- /dev/null
+++ b/src/compiler/transformers/es5.ts
@@ -0,0 +1,83 @@
+/// <reference path="../factory.ts" />
+/// <reference path="../visitor.ts" />
+
+/*@internal*/
+namespace ts {
+    /**
+     * Transforms ES5 syntax into ES3 syntax.
+     *
+     * @param context Context and state information for the transformation.
+     */
+    export function transformES5(context: TransformationContext) {
+        const previousOnSubstituteNode = context.onSubstituteNode;
+        context.onSubstituteNode = onSubstituteNode;
+        context.enableSubstitution(SyntaxKind.PropertyAccessExpression);
+        context.enableSubstitution(SyntaxKind.PropertyAssignment);
+        return transformSourceFile;
+
+        /**
+         * Transforms an ES5 source file to ES3.
+         *
+         * @param node A SourceFile
+         */
+        function transformSourceFile(node: SourceFile) {
+            return node;
+        }
+
+        /**
+         * Hooks node substitutions.
+         *
+         * @param emitContext The context for the emitter.
+         * @param node The node to substitute.
+         */
+        function onSubstituteNode(emitContext: EmitContext, node: Node) {
+            node = previousOnSubstituteNode(emitContext, node);
+            if (isPropertyAccessExpression(node)) {
+                return substitutePropertyAccessExpression(node);
+            }
+            else if (isPropertyAssignment(node)) {
+                return substitutePropertyAssignment(node);
+            }
+            return node;
+        }
+
+        /**
+         * Substitutes a PropertyAccessExpression whose name is a reserved word.
+         *
+         * @param node A PropertyAccessExpression
+         */
+        function substitutePropertyAccessExpression(node: PropertyAccessExpression): Expression {
+            const literalName = trySubstituteReservedName(node.name);
+            if (literalName) {
+                return createElementAccess(node.expression, literalName, /*location*/ node);
+            }
+            return node;
+        }
+
+        /**
+         * Substitutes a PropertyAssignment whose name is a reserved word.
+         *
+         * @param node A PropertyAssignment
+         */
+        function substitutePropertyAssignment(node: PropertyAssignment): PropertyAssignment {
+            const literalName = isIdentifier(node.name) && trySubstituteReservedName(node.name);
+            if (literalName) {
+                return updatePropertyAssignment(node, literalName, node.initializer);
+            }
+            return node;
+        }
+
+        /**
+         * If an identifier name is a reserved word, returns a string literal for the name.
+         *
+         * @param name An Identifier
+         */
+        function trySubstituteReservedName(name: Identifier) {
+            const token = name.originalKeywordKind || (nodeIsSynthesized(name) ? stringToToken(name.text) : undefined);
+            if (token >= SyntaxKind.FirstReservedWord && token <= SyntaxKind.LastReservedWord) {
+                return createLiteral(name, /*location*/ name);
+            }
+            return undefined;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/compiler/transformers/module/module.ts b/src/compiler/transformers/module/module.ts
index b91f67382cd1f..1cca7a21777f5 100644
--- a/src/compiler/transformers/module/module.ts
+++ b/src/compiler/transformers/module/module.ts
@@ -958,39 +958,19 @@ namespace ts {
                 const declaration = resolver.getReferencedImportDeclaration(node);
                 if (declaration) {
                     if (isImportClause(declaration)) {
-                        if (languageVersion >= ScriptTarget.ES5) {
-                            return createPropertyAccess(
-                                getGeneratedNameForNode(declaration.parent),
-                                createIdentifier("default"),
-                                /*location*/ node
-                            );
-                        }
-                        else {
-                            // TODO: ES3 transform to handle x.default -> x["default"]
-                            return createElementAccess(
-                                getGeneratedNameForNode(declaration.parent),
-                                createLiteral("default"),
-                                /*location*/ node
-                            );
-                        }
+                        return createPropertyAccess(
+                            getGeneratedNameForNode(declaration.parent),
+                            createIdentifier("default"),
+                            /*location*/ node
+                        );
                     }
                     else if (isImportSpecifier(declaration)) {
                         const name = declaration.propertyName || declaration.name;
-                        if (name.originalKeywordKind === SyntaxKind.DefaultKeyword && languageVersion <= ScriptTarget.ES3) {
-                            // TODO: ES3 transform to handle x.default -> x["default"]
-                            return createElementAccess(
-                                getGeneratedNameForNode(declaration.parent.parent.parent),
-                                createLiteral(name.text),
-                                /*location*/ node
-                            );
-                        }
-                        else {
-                            return createPropertyAccess(
-                                getGeneratedNameForNode(declaration.parent.parent.parent),
-                                getSynthesizedClone(name),
-                                /*location*/ node
-                            );
-                        }
+                        return createPropertyAccess(
+                            getGeneratedNameForNode(declaration.parent.parent.parent),
+                            getSynthesizedClone(name),
+                            /*location*/ node
+                        );
                     }
                 }
             }
@@ -1027,15 +1007,10 @@ namespace ts {
 
         function createExportAssignment(name: Identifier, value: Expression) {
             return createAssignment(
-                name.originalKeywordKind === SyntaxKind.DefaultKeyword && languageVersion === ScriptTarget.ES3
-                    ? createElementAccess(
-                        createIdentifier("exports"),
-                        createLiteral(name.text)
-                    )
-                    : createPropertyAccess(
-                        createIdentifier("exports"),
-                        getSynthesizedClone(name)
-                    ),
+                createPropertyAccess(
+                    createIdentifier("exports"),
+                    getSynthesizedClone(name)
+                ),
                 value
             );
         }
diff --git a/src/compiler/transformers/module/system.ts b/src/compiler/transformers/module/system.ts
index b33b3058f8caf..775d8fc34f9b5 100644
--- a/src/compiler/transformers/module/system.ts
+++ b/src/compiler/transformers/module/system.ts
@@ -19,7 +19,6 @@ namespace ts {
         const compilerOptions = context.getCompilerOptions();
         const resolver = context.getEmitResolver();
         const host = context.getEmitHost();
-        const languageVersion = getEmitScriptTarget(compilerOptions);
         const previousOnSubstituteNode = context.onSubstituteNode;
         const previousOnEmitNode = context.onEmitNode;
         context.onSubstituteNode = onSubstituteNode;
@@ -1317,12 +1316,7 @@ namespace ts {
                 return undefined;
             }
 
-            if (name.originalKeywordKind && languageVersion === ScriptTarget.ES3) {
-                return createElementAccess(importAlias, createLiteral(name.text));
-            }
-            else {
-                return createPropertyAccess(importAlias, getSynthesizedClone(name));
-            }
+            return createPropertyAccess(importAlias, getSynthesizedClone(name));
         }
 
         function collectDependencyGroups(externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[]) {
diff --git a/src/compiler/tsconfig.json b/src/compiler/tsconfig.json
index da356c0b4d327..cc1f3125166eb 100644
--- a/src/compiler/tsconfig.json
+++ b/src/compiler/tsconfig.json
@@ -27,6 +27,7 @@
         "transformers/es2017.ts",
         "transformers/es2016.ts",
         "transformers/es2015.ts",
+        "transformers/es5.ts",
         "transformers/generators.ts",
         "transformers/destructuring.ts",
         "transformers/module/module.ts",
diff --git a/src/harness/tsconfig.json b/src/harness/tsconfig.json
index 5d7a81d1a7447..e5e14266ec740 100644
--- a/src/harness/tsconfig.json
+++ b/src/harness/tsconfig.json
@@ -29,6 +29,7 @@
         "../compiler/transformers/es2017.ts",
         "../compiler/transformers/es2016.ts",
         "../compiler/transformers/es2015.ts",
+        "../compiler/transformers/es5.ts",
         "../compiler/transformers/generators.ts",
         "../compiler/transformers/destructuring.ts",
         "../compiler/transformers/module/module.ts",
diff --git a/src/services/tsconfig.json b/src/services/tsconfig.json
index 03d04935068c0..1033a3aa55390 100644
--- a/src/services/tsconfig.json
+++ b/src/services/tsconfig.json
@@ -28,6 +28,7 @@
         "../compiler/transformers/es2017.ts",
         "../compiler/transformers/es2016.ts",
         "../compiler/transformers/es2015.ts",
+        "../compiler/transformers/es5.ts",
         "../compiler/transformers/generators.ts",
         "../compiler/transformers/destructuring.ts",
         "../compiler/transformers/module/module.ts",
diff --git a/tests/baselines/reference/allowSyntheticDefaultImports10.js b/tests/baselines/reference/allowSyntheticDefaultImports10.js
index 746997c4c8941..396cd75b57461 100644
--- a/tests/baselines/reference/allowSyntheticDefaultImports10.js
+++ b/tests/baselines/reference/allowSyntheticDefaultImports10.js
@@ -13,5 +13,5 @@ Foo.default.default.foo();
 //// [a.js]
 "use strict";
 var Foo = require("./b");
-Foo.default.bar();
-Foo.default.default.foo();
+Foo["default"].bar();
+Foo["default"]["default"].foo();
diff --git a/tests/baselines/reference/bluebirdStaticThis.js b/tests/baselines/reference/bluebirdStaticThis.js
index 301f32319a7b4..606f778323fdb 100644
--- a/tests/baselines/reference/bluebirdStaticThis.js
+++ b/tests/baselines/reference/bluebirdStaticThis.js
@@ -146,12 +146,12 @@ var x;
 var arr;
 var foo;
 var fooProm;
-fooProm = Promise.try(Promise, function () {
+fooProm = Promise["try"](Promise, function () {
     return foo;
 });
-fooProm = Promise.try(Promise, function () {
+fooProm = Promise["try"](Promise, function () {
     return foo;
 }, arr);
-fooProm = Promise.try(Promise, function () {
+fooProm = Promise["try"](Promise, function () {
     return foo;
 }, arr, x);
diff --git a/tests/baselines/reference/classMethodWithKeywordName1.js b/tests/baselines/reference/classMethodWithKeywordName1.js
index 6e1faee005cc0..a7cb994bfb397 100644
--- a/tests/baselines/reference/classMethodWithKeywordName1.js
+++ b/tests/baselines/reference/classMethodWithKeywordName1.js
@@ -7,6 +7,6 @@ class C {
 var C = (function () {
     function C() {
     }
-    C.try = function () { };
+    C["try"] = function () { };
     return C;
 }());
diff --git a/tests/baselines/reference/constructorWithIncompleteTypeAnnotation.js b/tests/baselines/reference/constructorWithIncompleteTypeAnnotation.js
index 2e3190c15c825..1ee309b0eb424 100644
--- a/tests/baselines/reference/constructorWithIncompleteTypeAnnotation.js
+++ b/tests/baselines/reference/constructorWithIncompleteTypeAnnotation.js
@@ -292,7 +292,7 @@ var TypeScriptAllInOne;
 (function (TypeScriptAllInOne) {
     var Program = (function () {
         function Program() {
-            this.case = bfs.STATEMENTS(4);
+            this["case"] = bfs.STATEMENTS(4);
         }
         Program.Main = function () {
             var args = [];
@@ -305,13 +305,13 @@ var TypeScriptAllInOne;
                 retValue = bfs.VARIABLES();
                 if (retValue != 0)
                      ^= {
-                        return: 1
+                        "return": 1
                     };
             }
             finally {
             }
         };
-        Program.prototype.if = function (retValue) {
+        Program.prototype["if"] = function (retValue) {
             if (retValue === void 0) { retValue =  != 0; }
             return 1;
                 ^
@@ -327,7 +327,7 @@ var TypeScriptAllInOne;
                 return 1;
             }
         };
-        Program.prototype.catch = function (e) {
+        Program.prototype["catch"] = function (e) {
             console.log(e);
         };
         return Program;
@@ -364,7 +364,7 @@ var BasicFeatures = (function () {
         ;
         var quoted = '"', quoted2 = "'";
         var reg = /\w*/;
-        var objLit = { "var": number = 42, equals: function (x) { return x["var"] === 42; }, instanceof: function () { return 'objLit{42}'; } };
+        var objLit = { "var": number = 42, equals: function (x) { return x["var"] === 42; }, "instanceof": function () { return 'objLit{42}'; } };
         var weekday = Weekdays.Monday;
         var con = char + f + hexchar + float.toString() + float2.toString() + reg.toString() + objLit + weekday;
         //
diff --git a/tests/baselines/reference/convertKeywordsYes.js b/tests/baselines/reference/convertKeywordsYes.js
index ba3c661d1d031..b7bd60e4a9535 100644
--- a/tests/baselines/reference/convertKeywordsYes.js
+++ b/tests/baselines/reference/convertKeywordsYes.js
@@ -344,43 +344,43 @@ var bigObject = {
     string: 0,
     get: 0,
     yield: 0,
-    break: 0,
-    case: 0,
-    catch: 0,
-    class: 0,
-    continue: 0,
-    const: 0,
-    debugger: 0,
+    "break": 0,
+    "case": 0,
+    "catch": 0,
+    "class": 0,
+    "continue": 0,
+    "const": 0,
+    "debugger": 0,
     declare: 0,
-    default: 0,
-    delete: 0,
-    do: 0,
-    else: 0,
-    enum: 0,
-    export: 0,
-    extends: 0,
-    false: 0,
-    finally: 0,
-    for: 0,
-    function: 0,
-    if: 0,
-    import: 0,
-    in: 0,
-    instanceof: 0,
-    new: 0,
-    null: 0,
-    return: 0,
-    super: 0,
-    switch: 0,
-    this: 0,
-    throw: 0,
-    true: 0,
-    try: 0,
-    typeof: 0,
-    var: 0,
-    void: 0,
-    while: 0,
-    with: 0
+    "default": 0,
+    "delete": 0,
+    "do": 0,
+    "else": 0,
+    "enum": 0,
+    "export": 0,
+    "extends": 0,
+    "false": 0,
+    "finally": 0,
+    "for": 0,
+    "function": 0,
+    "if": 0,
+    "import": 0,
+    "in": 0,
+    "instanceof": 0,
+    "new": 0,
+    "null": 0,
+    "return": 0,
+    "super": 0,
+    "switch": 0,
+    "this": 0,
+    "throw": 0,
+    "true": 0,
+    "try": 0,
+    "typeof": 0,
+    "var": 0,
+    "void": 0,
+    "while": 0,
+    "with": 0
 };
 var bigClass = (function () {
     function bigClass() {
@@ -401,43 +401,43 @@ var bigClass = (function () {
         this.string = 0;
         this.get = 0;
         this.yield = 0;
-        this.break = 0;
-        this.case = 0;
-        this.catch = 0;
-        this.class = 0;
-        this.continue = 0;
-        this.const = 0;
-        this.debugger = 0;
+        this["break"] = 0;
+        this["case"] = 0;
+        this["catch"] = 0;
+        this["class"] = 0;
+        this["continue"] = 0;
+        this["const"] = 0;
+        this["debugger"] = 0;
         this.declare = 0;
-        this.default = 0;
-        this.delete = 0;
-        this.do = 0;
-        this.else = 0;
-        this.enum = 0;
-        this.export = 0;
-        this.extends = 0;
-        this.false = 0;
-        this.finally = 0;
-        this.for = 0;
-        this.function = 0;
-        this.if = 0;
-        this.import = 0;
-        this.in = 0;
-        this.instanceof = 0;
-        this.new = 0;
-        this.null = 0;
-        this.return = 0;
-        this.super = 0;
-        this.switch = 0;
-        this.this = 0;
-        this.throw = 0;
-        this.true = 0;
-        this.try = 0;
-        this.typeof = 0;
-        this.var = 0;
-        this.void = 0;
-        this.while = 0;
-        this.with = 0;
+        this["default"] = 0;
+        this["delete"] = 0;
+        this["do"] = 0;
+        this["else"] = 0;
+        this["enum"] = 0;
+        this["export"] = 0;
+        this["extends"] = 0;
+        this["false"] = 0;
+        this["finally"] = 0;
+        this["for"] = 0;
+        this["function"] = 0;
+        this["if"] = 0;
+        this["import"] = 0;
+        this["in"] = 0;
+        this["instanceof"] = 0;
+        this["new"] = 0;
+        this["null"] = 0;
+        this["return"] = 0;
+        this["super"] = 0;
+        this["switch"] = 0;
+        this["this"] = 0;
+        this["throw"] = 0;
+        this["true"] = 0;
+        this["try"] = 0;
+        this["typeof"] = 0;
+        this["var"] = 0;
+        this["void"] = 0;
+        this["while"] = 0;
+        this["with"] = 0;
     }
     return bigClass;
 }());
diff --git a/tests/baselines/reference/destructuringParameterDeclaration6.js b/tests/baselines/reference/destructuringParameterDeclaration6.js
index ad86b2983b3c3..03307415b6514 100644
--- a/tests/baselines/reference/destructuringParameterDeclaration6.js
+++ b/tests/baselines/reference/destructuringParameterDeclaration6.js
@@ -27,7 +27,7 @@ b2({ while: 1 });
 "use strict";
 // Error
 function a(_a) {
-    var  = _a.while;
+    var  = _a["while"];
 }
 function a1(_a) {
     var public = _a.public;
@@ -56,13 +56,13 @@ function a7() {
         a[_i - 0] = arguments[_i];
     }
 }
-a({ while: 1 });
+a({ "while": 1 });
 // No Error
 function b1(_a) {
     var x = _a.public;
 }
 function b2(_a) {
-    var y = _a.while;
+    var y = _a["while"];
 }
 b1({ public: 1 });
-b2({ while: 1 });
+b2({ "while": 1 });
diff --git a/tests/baselines/reference/es6ClassTest5.js b/tests/baselines/reference/es6ClassTest5.js
index b909fac58b50f..7d4238fda65b1 100644
--- a/tests/baselines/reference/es6ClassTest5.js
+++ b/tests/baselines/reference/es6ClassTest5.js
@@ -23,7 +23,7 @@ var C1T5 = (function () {
 }());
 var bigClass = (function () {
     function bigClass() {
-        this.break = 1;
+        this["break"] = 1;
     }
     return bigClass;
 }());
diff --git a/tests/baselines/reference/fatarrowfunctionsErrors.js b/tests/baselines/reference/fatarrowfunctionsErrors.js
index 2ac20f1966ade..ced4660d8d10b 100644
--- a/tests/baselines/reference/fatarrowfunctionsErrors.js
+++ b/tests/baselines/reference/fatarrowfunctionsErrors.js
@@ -20,7 +20,7 @@ foo(function () {
     }
     return 0;
 });
-foo((1), { return: 0 });
+foo((1), { "return": 0 });
 foo(function (x) { return x; });
 foo(function (x) {
     if (x === void 0) { x = 0; }
diff --git a/tests/baselines/reference/keywordField.js b/tests/baselines/reference/keywordField.js
index 581d5afa14a38..a146cffade84f 100644
--- a/tests/baselines/reference/keywordField.js
+++ b/tests/baselines/reference/keywordField.js
@@ -12,7 +12,7 @@ var q = a["if"];
 
 //// [keywordField.js]
 var obj = {};
-obj.if = 1;
-var a = { if: "test" };
-var n = a.if;
+obj["if"] = 1;
+var a = { "if": "test" };
+var n = a["if"];
 var q = a["if"];
diff --git a/tests/baselines/reference/keywordInJsxIdentifier.js b/tests/baselines/reference/keywordInJsxIdentifier.js
index 6009e1980e639..d9c3b51e9a30b 100644
--- a/tests/baselines/reference/keywordInJsxIdentifier.js
+++ b/tests/baselines/reference/keywordInJsxIdentifier.js
@@ -9,6 +9,6 @@ declare var React: any;
 
 //// [keywordInJsxIdentifier.js]
 React.createElement("foo", { "class-id": true });
-React.createElement("foo", { class: true });
+React.createElement("foo", { "class": true });
 React.createElement("foo", { "class-id": "1" });
-React.createElement("foo", { class: "1" });
+React.createElement("foo", { "class": "1" });
diff --git a/tests/baselines/reference/nestedClassDeclaration.js b/tests/baselines/reference/nestedClassDeclaration.js
index 04e2f6348efb6..cc300ec75a31c 100644
--- a/tests/baselines/reference/nestedClassDeclaration.js
+++ b/tests/baselines/reference/nestedClassDeclaration.js
@@ -38,5 +38,5 @@ function foo() {
     }());
 }
 var x = {
-    class: C4
+    "class": C4
 }, _a = void 0;
diff --git a/tests/baselines/reference/objectBindingPatternKeywordIdentifiers01.js b/tests/baselines/reference/objectBindingPatternKeywordIdentifiers01.js
index cd339bb590716..a905e53f22122 100644
--- a/tests/baselines/reference/objectBindingPatternKeywordIdentifiers01.js
+++ b/tests/baselines/reference/objectBindingPatternKeywordIdentifiers01.js
@@ -3,4 +3,4 @@
 var { while } = { while: 1 }
 
 //// [objectBindingPatternKeywordIdentifiers01.js]
-var  = { while: 1 }.while;
+var  = { "while": 1 }["while"];
diff --git a/tests/baselines/reference/objectBindingPatternKeywordIdentifiers02.js b/tests/baselines/reference/objectBindingPatternKeywordIdentifiers02.js
index 0286a78ba8227..5bc6e1f996367 100644
--- a/tests/baselines/reference/objectBindingPatternKeywordIdentifiers02.js
+++ b/tests/baselines/reference/objectBindingPatternKeywordIdentifiers02.js
@@ -3,4 +3,4 @@
 var { while: while } = { while: 1 }
 
 //// [objectBindingPatternKeywordIdentifiers02.js]
-var _a = { while: 1 },  = _a.while,  = _a.while;
+var _a = { "while": 1 },  = _a["while"],  = _a["while"];
diff --git a/tests/baselines/reference/objectBindingPatternKeywordIdentifiers03.js b/tests/baselines/reference/objectBindingPatternKeywordIdentifiers03.js
index 4bbb1afb4cb5b..3d8643d63ce28 100644
--- a/tests/baselines/reference/objectBindingPatternKeywordIdentifiers03.js
+++ b/tests/baselines/reference/objectBindingPatternKeywordIdentifiers03.js
@@ -3,4 +3,4 @@
 var { "while" } = { while: 1 }
 
 //// [objectBindingPatternKeywordIdentifiers03.js]
-var  = { while: 1 }["while"];
+var  = { "while": 1 }["while"];
diff --git a/tests/baselines/reference/objectBindingPatternKeywordIdentifiers04.js b/tests/baselines/reference/objectBindingPatternKeywordIdentifiers04.js
index 4e53b13c0a6ba..de7608a77d22d 100644
--- a/tests/baselines/reference/objectBindingPatternKeywordIdentifiers04.js
+++ b/tests/baselines/reference/objectBindingPatternKeywordIdentifiers04.js
@@ -3,4 +3,4 @@
 var { "while": while } = { while: 1 }
 
 //// [objectBindingPatternKeywordIdentifiers04.js]
-var _a = { while: 1 },  = _a["while"],  = _a.while;
+var _a = { "while": 1 },  = _a["while"],  = _a["while"];
diff --git a/tests/baselines/reference/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.js b/tests/baselines/reference/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.js
index b72f0351b9c82..7b9c9f5d32850 100644
--- a/tests/baselines/reference/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.js
+++ b/tests/baselines/reference/objectLiteralShorthandPropertiesErrorFromNotUsingIdentifier.js
@@ -27,15 +27,15 @@ var y = {
     42: ,
     get e() { },
     set f() { },
-    this: ,
-    super: ,
-    var: ,
-    class: ,
-    typeof: 
+    "this": ,
+    "super": ,
+    "var": ,
+    "class": ,
+    "typeof": 
 };
 var x = {
     a: .b,
     a: ["ss"],
     a: [1]
 };
-var v = { class:  }; // error
+var v = { "class":  }; // error
diff --git a/tests/baselines/reference/objectTypesIdentityWithConstructSignatures2.js b/tests/baselines/reference/objectTypesIdentityWithConstructSignatures2.js
index 315e079d429bf..0a422dbda6f0f 100644
--- a/tests/baselines/reference/objectTypesIdentityWithConstructSignatures2.js
+++ b/tests/baselines/reference/objectTypesIdentityWithConstructSignatures2.js
@@ -91,7 +91,7 @@ var C = (function () {
     return C;
 }());
 var a;
-var b = { new: function (x) { return ''; } }; // not a construct signature, function called new
+var b = { "new": function (x) { return ''; } }; // not a construct signature, function called new
 function foo1b(x) { }
 function foo1c(x) { }
 function foo2(x) { }
diff --git a/tests/baselines/reference/objectTypesIdentityWithConstructSignaturesDifferingParamCounts.js b/tests/baselines/reference/objectTypesIdentityWithConstructSignaturesDifferingParamCounts.js
index a61bedfd52f23..5fa148b541d45 100644
--- a/tests/baselines/reference/objectTypesIdentityWithConstructSignaturesDifferingParamCounts.js
+++ b/tests/baselines/reference/objectTypesIdentityWithConstructSignaturesDifferingParamCounts.js
@@ -91,7 +91,7 @@ var C = (function () {
     return C;
 }());
 var a;
-var b = { new: function (x) { return ''; } }; // not a construct signature, function called new
+var b = { "new": function (x) { return ''; } }; // not a construct signature, function called new
 function foo1b(x) { }
 function foo1c(x) { }
 function foo2(x) { }
diff --git a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByConstraints.js b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByConstraints.js
index c15c53b9bf80d..6a66e8bbda3b9 100644
--- a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByConstraints.js
+++ b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByConstraints.js
@@ -92,7 +92,7 @@ var C = (function () {
     return C;
 }());
 var a;
-var b = { new: function (x) { return ''; } }; // not a construct signature, function called new
+var b = { "new": function (x) { return ''; } }; // not a construct signature, function called new
 function foo1b(x) { }
 function foo1c(x) { }
 function foo2(x) { }
diff --git a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByConstraints2.js b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByConstraints2.js
index f8aff596dc9c5..e19837a9f7f2c 100644
--- a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByConstraints2.js
+++ b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByConstraints2.js
@@ -109,7 +109,7 @@ var D = (function () {
     return D;
 }());
 var a;
-var b = { new: function (x, y) { return ''; } }; // not a construct signature, function called new
+var b = { "new": function (x, y) { return ''; } }; // not a construct signature, function called new
 function foo1b(x) { }
 function foo1c(x) { }
 function foo2(x) { }
diff --git a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByConstraints3.js b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByConstraints3.js
index 141aa86823b27..735c5bdc2d69c 100644
--- a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByConstraints3.js
+++ b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByConstraints3.js
@@ -128,7 +128,7 @@ var D = (function () {
     return D;
 }());
 var a;
-var b = { new: function (x, y) { return ''; } }; // not a construct signature, function called new
+var b = { "new": function (x, y) { return ''; } }; // not a construct signature, function called new
 function foo1b(x) { }
 function foo1c(x) { }
 function foo2(x) { }
diff --git a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByReturnType.js b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByReturnType.js
index b651d368f334b..6eab84a49ddb4 100644
--- a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByReturnType.js
+++ b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByReturnType.js
@@ -99,7 +99,7 @@ var C = (function () {
     return C;
 }());
 var a;
-var b = { new: function (x) { return null; } }; // not a construct signature, function called new
+var b = { "new": function (x) { return null; } }; // not a construct signature, function called new
 function foo1b(x) { }
 function foo1c(x) { }
 function foo2(x) { }
diff --git a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByReturnType2.js b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByReturnType2.js
index ff7095c4ea1a1..d927a8e082a22 100644
--- a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByReturnType2.js
+++ b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingByReturnType2.js
@@ -95,7 +95,7 @@ var C = (function () {
     return C;
 }());
 var a;
-var b = { new: function (x) { return null; } }; // not a construct signature, function called new
+var b = { "new": function (x) { return null; } }; // not a construct signature, function called new
 function foo1b(x) { }
 function foo1c(x) { }
 function foo2(x) { }
diff --git a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingTypeParameterCounts.js b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingTypeParameterCounts.js
index 314eb700c4b19..512bebb3b0e8d 100644
--- a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingTypeParameterCounts.js
+++ b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingTypeParameterCounts.js
@@ -87,7 +87,7 @@ var C = (function () {
     return C;
 }());
 var a;
-var b = { new: function (x) { return x; } };
+var b = { "new": function (x) { return x; } };
 function foo1b(x) { }
 function foo1c(x) { }
 function foo2(x) { }
diff --git a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingTypeParameterNames.js b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingTypeParameterNames.js
index 182cf8263b779..80cfcd23ec9c3 100644
--- a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingTypeParameterNames.js
+++ b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesDifferingTypeParameterNames.js
@@ -87,7 +87,7 @@ var C = (function () {
     return C;
 }());
 var a;
-var b = { new: function (x) { return new C(x); } };
+var b = { "new": function (x) { return new C(x); } };
 function foo1b(x) { }
 function foo1c(x) { }
 function foo2(x) { }
diff --git a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesOptionalParams.js b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesOptionalParams.js
index 5c5dd26c33171..87cb0b33531e5 100644
--- a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesOptionalParams.js
+++ b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesOptionalParams.js
@@ -91,7 +91,7 @@ var C = (function () {
     return C;
 }());
 var a;
-var b = { new: function (x, y) { return new C(x, y); } }; // not a construct signature, function called new
+var b = { "new": function (x, y) { return new C(x, y); } }; // not a construct signature, function called new
 function foo1b(x) { }
 function foo1c(x) { }
 function foo2(x) { }
diff --git a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesOptionalParams2.js b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesOptionalParams2.js
index 14b2ec3c0ca0a..6b0e91f817ff9 100644
--- a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesOptionalParams2.js
+++ b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesOptionalParams2.js
@@ -91,7 +91,7 @@ var C = (function () {
     return C;
 }());
 var a;
-var b = { new: function (x, y) { return new C(x, y); } }; // not a construct signature, function called new
+var b = { "new": function (x, y) { return new C(x, y); } }; // not a construct signature, function called new
 function foo1b(x) { }
 function foo1c(x) { }
 function foo2(x) { }
diff --git a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesOptionalParams3.js b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesOptionalParams3.js
index ffc238cacae09..55f2a0217e934 100644
--- a/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesOptionalParams3.js
+++ b/tests/baselines/reference/objectTypesIdentityWithGenericConstructSignaturesOptionalParams3.js
@@ -91,7 +91,7 @@ var C = (function () {
     return C;
 }());
 var a;
-var b = { new: function (x, y) { return new C(x, y); } }; // not a construct signature, function called new
+var b = { "new": function (x, y) { return new C(x, y); } }; // not a construct signature, function called new
 function foo1b(x) { }
 function foo1c(x) { }
 function foo2(x) { }
diff --git a/tests/baselines/reference/parserErrorRecovery_ObjectLiteral2.js b/tests/baselines/reference/parserErrorRecovery_ObjectLiteral2.js
index 6a703759fff75..c206a30237a5e 100644
--- a/tests/baselines/reference/parserErrorRecovery_ObjectLiteral2.js
+++ b/tests/baselines/reference/parserErrorRecovery_ObjectLiteral2.js
@@ -4,4 +4,4 @@ return;
 
 //// [parserErrorRecovery_ObjectLiteral2.js]
 var v = { a: ,
-    return:  };
+    "return":  };
diff --git a/tests/baselines/reference/parserErrorRecovery_ObjectLiteral3.js b/tests/baselines/reference/parserErrorRecovery_ObjectLiteral3.js
index eecf45fea4fa0..6cee2b4272519 100644
--- a/tests/baselines/reference/parserErrorRecovery_ObjectLiteral3.js
+++ b/tests/baselines/reference/parserErrorRecovery_ObjectLiteral3.js
@@ -4,4 +4,4 @@ return;
 
 //// [parserErrorRecovery_ObjectLiteral3.js]
 var v = { a: ,
-    return:  };
+    "return":  };
diff --git a/tests/baselines/reference/parserErrorRecovery_ObjectLiteral4.js b/tests/baselines/reference/parserErrorRecovery_ObjectLiteral4.js
index 87a1a31437ef7..23d17c8047b5c 100644
--- a/tests/baselines/reference/parserErrorRecovery_ObjectLiteral4.js
+++ b/tests/baselines/reference/parserErrorRecovery_ObjectLiteral4.js
@@ -4,4 +4,4 @@ return;
 
 //// [parserErrorRecovery_ObjectLiteral4.js]
 var v = { a: 1,
-    return:  };
+    "return":  };
diff --git a/tests/baselines/reference/parserErrorRecovery_ObjectLiteral5.js b/tests/baselines/reference/parserErrorRecovery_ObjectLiteral5.js
index 97e618946a0e2..7b83132bf0fb4 100644
--- a/tests/baselines/reference/parserErrorRecovery_ObjectLiteral5.js
+++ b/tests/baselines/reference/parserErrorRecovery_ObjectLiteral5.js
@@ -4,4 +4,4 @@ return;
 
 //// [parserErrorRecovery_ObjectLiteral5.js]
 var v = { a: 1,
-    return:  };
+    "return":  };
diff --git a/tests/baselines/reference/parserExportAsFunctionIdentifier.js b/tests/baselines/reference/parserExportAsFunctionIdentifier.js
index 7ed76bb87d945..62429c76855c7 100644
--- a/tests/baselines/reference/parserExportAsFunctionIdentifier.js
+++ b/tests/baselines/reference/parserExportAsFunctionIdentifier.js
@@ -9,4 +9,4 @@ var x = f.export();
 
 //// [parserExportAsFunctionIdentifier.js]
 var f;
-var x = f.export();
+var x = f["export"]();
diff --git a/tests/baselines/reference/parserKeywordsAsIdentifierName1.js b/tests/baselines/reference/parserKeywordsAsIdentifierName1.js
index c0c8c8443647f..a717abcc08ba0 100644
--- a/tests/baselines/reference/parserKeywordsAsIdentifierName1.js
+++ b/tests/baselines/reference/parserKeywordsAsIdentifierName1.js
@@ -8,7 +8,7 @@ var big = {
 
 //// [parserKeywordsAsIdentifierName1.js]
 var big = {
-    break: 0,
-    super: 0,
-    const: 0
+    "break": 0,
+    "super": 0,
+    "const": 0
 };
diff --git a/tests/baselines/reference/parserShorthandPropertyAssignment2.js b/tests/baselines/reference/parserShorthandPropertyAssignment2.js
index 0de0fa3829fc6..95d2f32ffad0e 100644
--- a/tests/baselines/reference/parserShorthandPropertyAssignment2.js
+++ b/tests/baselines/reference/parserShorthandPropertyAssignment2.js
@@ -2,4 +2,4 @@
 var v = { class };
 
 //// [parserShorthandPropertyAssignment2.js]
-var v = { class:  };
+var v = { "class":  };
diff --git a/tests/baselines/reference/parserSuperExpression3.js b/tests/baselines/reference/parserSuperExpression3.js
index f311efcd0f6a8..064353669c80c 100644
--- a/tests/baselines/reference/parserSuperExpression3.js
+++ b/tests/baselines/reference/parserSuperExpression3.js
@@ -10,7 +10,7 @@ var C = (function () {
     function C() {
     }
     C.prototype.M = function () {
-        this.super(0);
+        this["super"](0);
     };
     return C;
 }());
diff --git a/tests/baselines/reference/prototypeOnConstructorFunctions.js b/tests/baselines/reference/prototypeOnConstructorFunctions.js
index d2e5ddde9251f..de1fec1f7e8ac 100644
--- a/tests/baselines/reference/prototypeOnConstructorFunctions.js
+++ b/tests/baselines/reference/prototypeOnConstructorFunctions.js
@@ -12,4 +12,4 @@ i.const.prototype.prop = "yo";
 
 //// [prototypeOnConstructorFunctions.js]
 var i;
-i.const.prototype.prop = "yo";
+i["const"].prototype.prop = "yo";
diff --git a/tests/baselines/reference/reservedWords.js b/tests/baselines/reference/reservedWords.js
index 12fbcae0c651e..3424c05418175 100644
--- a/tests/baselines/reference/reservedWords.js
+++ b/tests/baselines/reference/reservedWords.js
@@ -19,16 +19,16 @@ var obj2 = {
 
 //// [reservedWords.js]
 var obj = {
-    if: 0,
-    debugger: 2,
-    break: 3,
-    function: 4
+    "if": 0,
+    "debugger": 2,
+    "break": 3,
+    "function": 4
 };
 //This compiles.
 var obj2 = {
-    if: 0,
-    while: 1,
-    debugger: 2,
-    break: 3,
-    function: 4
+    "if": 0,
+    "while": 1,
+    "debugger": 2,
+    "break": 3,
+    "function": 4
 };
diff --git a/tests/baselines/reference/reservedWords2.js b/tests/baselines/reference/reservedWords2.js
index a79a0564c788d..d9c8105c35f5b 100644
--- a/tests/baselines/reference/reservedWords2.js
+++ b/tests/baselines/reference/reservedWords2.js
@@ -27,8 +27,8 @@ function () { }
 throw function () { };
 module;
 void {};
-var _a = { while: 1, return: 2 },  = _a.while,  = _a.return;
-var _b = { this: 1, switch: { continue: 2 } },  = _b.this,  = _b.switch.continue;
+var _a = { "while": 1, "return": 2 },  = _a["while"],  = _a["return"];
+var _b = { "this": 1, "switch": { "continue": 2 } },  = _b["this"],  = _b["switch"]["continue"];
 var _c = void 0;
 debugger;
 if ()
diff --git a/tests/baselines/reference/super1.js b/tests/baselines/reference/super1.js
index 9f1289dce554c..0094f696fafb5 100644
--- a/tests/baselines/reference/super1.js
+++ b/tests/baselines/reference/super1.js
@@ -97,7 +97,7 @@ var SubSub1 = (function (_super) {
         return _super.apply(this, arguments) || this;
     }
     SubSub1.prototype.bar = function () {
-        return _super.prototype.super.foo;
+        return _super.prototype["super"].foo;
     };
     return SubSub1;
 }(Sub1));
diff --git a/tests/baselines/reference/tsxReactEmitNesting.js b/tests/baselines/reference/tsxReactEmitNesting.js
index 29e948f687b32..eaee315c340cb 100644
--- a/tests/baselines/reference/tsxReactEmitNesting.js
+++ b/tests/baselines/reference/tsxReactEmitNesting.js
@@ -38,21 +38,21 @@ let render = (ctrl, model) =>
 //// [file.js]
 // A simple render function with nesting and control statements
 var render = function (ctrl, model) {
-    return vdom.createElement("section", { class: "todoapp" },
-        vdom.createElement("header", { class: "header" },
+    return vdom.createElement("section", { "class": "todoapp" },
+        vdom.createElement("header", { "class": "header" },
             vdom.createElement("h1", null, "todos <x>"),
-            vdom.createElement("input", { class: "new-todo", autofocus: true, autocomplete: "off", placeholder: "What needs to be done?", value: model.newTodo, onKeyup: ctrl.addTodo.bind(ctrl, model) })),
-        vdom.createElement("section", { class: "main", style: { display: (model.todos && model.todos.length) ? "block" : "none" } },
-            vdom.createElement("input", { class: "toggle-all", type: "checkbox", onChange: ctrl.toggleAll.bind(ctrl) }),
-            vdom.createElement("ul", { class: "todo-list" }, model.filteredTodos.map(function (todo) {
-                return vdom.createElement("li", { class: { todo: true, completed: todo.completed, editing: todo == model.editedTodo } },
-                    vdom.createElement("div", { class: "view" },
+            vdom.createElement("input", { "class": "new-todo", autofocus: true, autocomplete: "off", placeholder: "What needs to be done?", value: model.newTodo, onKeyup: ctrl.addTodo.bind(ctrl, model) })),
+        vdom.createElement("section", { "class": "main", style: { display: (model.todos && model.todos.length) ? "block" : "none" } },
+            vdom.createElement("input", { "class": "toggle-all", type: "checkbox", onChange: ctrl.toggleAll.bind(ctrl) }),
+            vdom.createElement("ul", { "class": "todo-list" }, model.filteredTodos.map(function (todo) {
+                return vdom.createElement("li", { "class": { todo: true, completed: todo.completed, editing: todo == model.editedTodo } },
+                    vdom.createElement("div", { "class": "view" },
                         (!todo.editable) ?
-                            vdom.createElement("input", { class: "toggle", type: "checkbox" })
+                            vdom.createElement("input", { "class": "toggle", type: "checkbox" })
                             : null,
                         vdom.createElement("label", { onDoubleClick: function () { ctrl.editTodo(todo); } }, todo.title),
-                        vdom.createElement("button", { class: "destroy", onClick: ctrl.removeTodo.bind(ctrl, todo) }),
-                        vdom.createElement("div", { class: "iconBorder" },
-                            vdom.createElement("div", { class: "icon" }))));
+                        vdom.createElement("button", { "class": "destroy", onClick: ctrl.removeTodo.bind(ctrl, todo) }),
+                        vdom.createElement("div", { "class": "iconBorder" },
+                            vdom.createElement("div", { "class": "icon" }))));
             }))));
 };
diff --git a/tests/baselines/reference/typeQueryWithReservedWords.js b/tests/baselines/reference/typeQueryWithReservedWords.js
index 7561eeddb7528..09c3b642a36d0 100644
--- a/tests/baselines/reference/typeQueryWithReservedWords.js
+++ b/tests/baselines/reference/typeQueryWithReservedWords.js
@@ -21,9 +21,9 @@ var Controller = (function () {
     }
     Controller.prototype.create = function () {
     };
-    Controller.prototype.delete = function () {
+    Controller.prototype["delete"] = function () {
     };
-    Controller.prototype.var = function () {
+    Controller.prototype["var"] = function () {
     };
     return Controller;
 }());

From f025e0caede7f9d2891c0e98c6e171c45864195e Mon Sep 17 00:00:00 2001
From: Ron Buckton <rbuckton@microsoft.com>
Date: Sun, 16 Oct 2016 15:19:02 -0700
Subject: [PATCH 053/224] Minor cleanup

---
 src/compiler/factory.ts                    |  62 +++-------
 src/compiler/transformers/es2015.ts        |  17 ++-
 src/compiler/transformers/generators.ts    |   6 +-
 src/compiler/transformers/module/module.ts |  25 ++---
 src/compiler/transformers/module/system.ts | 125 +++++++++------------
 src/compiler/transformers/ts.ts            |  51 ++++-----
 src/compiler/types.ts                      |   8 ++
 src/compiler/utilities.ts                  |   2 +-
 src/compiler/visitor.ts                    |   2 +-
 9 files changed, 136 insertions(+), 162 deletions(-)

diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 4194b7aaf5f4e..c42b16c5b8f3f 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -109,12 +109,12 @@ namespace ts {
     export function createLiteral(value: string | number | boolean, location?: TextRange): PrimaryExpression;
     export function createLiteral(value: string | number | boolean | StringLiteral | Identifier, location?: TextRange): PrimaryExpression {
         if (typeof value === "number") {
-            const node = <LiteralExpression>createNode(SyntaxKind.NumericLiteral, location, /*flags*/ undefined);
+            const node = <NumericLiteral>createNode(SyntaxKind.NumericLiteral, location, /*flags*/ undefined);
             node.text = value.toString();
             return node;
         }
         else if (typeof value === "boolean") {
-            return <PrimaryExpression>createNode(value ? SyntaxKind.TrueKeyword : SyntaxKind.FalseKeyword, location, /*flags*/ undefined);
+            return <BooleanLiteral>createNode(value ? SyntaxKind.TrueKeyword : SyntaxKind.FalseKeyword, location, /*flags*/ undefined);
         }
         else if (typeof value === "string") {
             const node = <StringLiteral>createNode(SyntaxKind.StringLiteral, location, /*flags*/ undefined);
@@ -226,20 +226,7 @@ namespace ts {
 
     // Signature elements
 
-    export function createParameter(name: string | Identifier | BindingPattern, initializer?: Expression, location?: TextRange) {
-        return createParameterDeclaration(
-            /*decorators*/ undefined,
-            /*modifiers*/ undefined,
-            /*dotDotDotToken*/ undefined,
-            name,
-            /*questionToken*/ undefined,
-            /*type*/ undefined,
-            initializer,
-            location
-        );
-    }
-
-    export function createParameterDeclaration(decorators: Decorator[], modifiers: Modifier[], dotDotDotToken: DotDotDotToken, name: string | Identifier | BindingPattern, questionToken: QuestionToken, type: TypeNode, initializer: Expression, location?: TextRange, flags?: NodeFlags) {
+    export function createParameter(decorators: Decorator[], modifiers: Modifier[], dotDotDotToken: DotDotDotToken, name: string | Identifier | BindingPattern, questionToken?: QuestionToken, type?: TypeNode, initializer?: Expression, location?: TextRange, flags?: NodeFlags) {
         const node = <ParameterDeclaration>createNode(SyntaxKind.Parameter, location, flags);
         node.decorators = decorators ? createNodeArray(decorators) : undefined;
         node.modifiers = modifiers ? createNodeArray(modifiers) : undefined;
@@ -251,9 +238,9 @@ namespace ts {
         return node;
     }
 
-    export function updateParameterDeclaration(node: ParameterDeclaration, decorators: Decorator[], modifiers: Modifier[], name: BindingName, type: TypeNode, initializer: Expression) {
+    export function updateParameter(node: ParameterDeclaration, decorators: Decorator[], modifiers: Modifier[], name: BindingName, type: TypeNode, initializer: Expression) {
         if (node.decorators !== decorators || node.modifiers !== modifiers || node.name !== name || node.type !== type || node.initializer !== initializer) {
-            return updateNode(createParameterDeclaration(decorators, modifiers, node.dotDotDotToken, name, node.questionToken, type, initializer, /*location*/ node, /*flags*/ node.flags), node);
+            return updateNode(createParameter(decorators, modifiers, node.dotDotDotToken, name, node.questionToken, type, initializer, /*location*/ node, /*flags*/ node.flags), node);
         }
 
         return node;
@@ -1557,18 +1544,6 @@ namespace ts {
         }
     }
 
-    export function createRestParameter(name: string | Identifier) {
-        return createParameterDeclaration(
-            /*decorators*/ undefined,
-            /*modifiers*/ undefined,
-            createToken(SyntaxKind.DotDotDotToken),
-            name,
-            /*questionToken*/ undefined,
-            /*type*/ undefined,
-            /*initializer*/ undefined
-        );
-    }
-
     export function createFunctionCall(func: Expression, thisArg: Expression, argumentsList: Expression[], location?: TextRange) {
         return createCall(
             createPropertyAccess(func, "call"),
@@ -1781,13 +1756,10 @@ namespace ts {
         return createArrowFunction(
             /*modifiers*/ undefined,
             /*typeParameters*/ undefined,
-            [createParameter("name")],
+            [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "name")],
             /*type*/ undefined,
-            /*equalsGreaterThanToken*/ undefined,
-            createElementAccess(
-                target,
-                createIdentifier("name")
-            )
+            createToken(SyntaxKind.EqualsGreaterThanToken),
+            createElementAccess(target, createIdentifier("name"))
         );
     }
 
@@ -1797,11 +1769,11 @@ namespace ts {
             /*modifiers*/ undefined,
             /*typeParameters*/ undefined,
             [
-                createParameter("name"),
-                createParameter("value")
+                createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "name"),
+                createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "value")
             ],
             /*type*/ undefined,
-            /*equalsGreaterThanToken*/ undefined,
+            createToken(SyntaxKind.EqualsGreaterThanToken),
             createAssignment(
                 createElementAccess(
                     target,
@@ -1853,7 +1825,7 @@ namespace ts {
             /*decorators*/ undefined,
             /*modifiers*/ undefined,
             "value",
-            [createParameter("v")],
+            [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "v")],
             createBlock([
                 createStatement(
                     createCall(
@@ -1873,9 +1845,9 @@ namespace ts {
             createArrowFunction(
                 /*modifiers*/ undefined,
                 /*typeParameters*/ undefined,
-                [createParameter("name")],
+                [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "name")],
                 /*type*/ undefined,
-                /*equalsGreaterThanToken*/ undefined,
+                createToken(SyntaxKind.EqualsGreaterThanToken),
                 createLogicalOr(
                     createElementAccess(
                         createIdentifier("cache"),
@@ -1915,8 +1887,8 @@ namespace ts {
                                 /*name*/ undefined,
                                 /*typeParameters*/ undefined,
                                 [
-                                    createParameter("geti"),
-                                    createParameter("seti")
+                                    createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "geti"),
+                                    createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "seti")
                                 ],
                                 /*type*/ undefined,
                                 createBlock([
@@ -2246,7 +2218,7 @@ namespace ts {
 
     /**
      * Ensures "use strict" directive is added
-     * 
+     *
      * @param node source file
      */
     export function ensureUseStrict(node: SourceFile): SourceFile {
diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
index bb2e8ac2aa501..22203876df400 100644
--- a/src/compiler/transformers/es2015.ts
+++ b/src/compiler/transformers/es2015.ts
@@ -685,7 +685,7 @@ namespace ts {
                 /*asteriskToken*/ undefined,
                 /*name*/ undefined,
                 /*typeParameters*/ undefined,
-                extendsClauseElement ? [createParameter("_super")] : [],
+                extendsClauseElement ? [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "_super")] : [],
                 /*type*/ undefined,
                 transformClassBody(node, extendsClauseElement)
             );
@@ -1035,7 +1035,12 @@ namespace ts {
                 // evaluated inside the function body.
                 return setOriginalNode(
                     createParameter(
+                        /*decorators*/ undefined,
+                        /*modifiers*/ undefined,
+                        /*dotDotDotToken*/ undefined,
                         getGeneratedNameForNode(node),
+                        /*questionToken*/ undefined,
+                        /*type*/ undefined,
                         /*initializer*/ undefined,
                         /*location*/ node
                     ),
@@ -1046,7 +1051,12 @@ namespace ts {
                 // Initializers are elided
                 return setOriginalNode(
                     createParameter(
+                        /*decorators*/ undefined,
+                        /*modifiers*/ undefined,
+                        /*dotDotDotToken*/ undefined,
                         node.name,
+                        /*questionToken*/ undefined,
+                        /*type*/ undefined,
                         /*initializer*/ undefined,
                         /*location*/ node
                     ),
@@ -2506,7 +2516,7 @@ namespace ts {
                 }
             }
             else {
-                loopParameters.push(createParameter(name));
+                loopParameters.push(createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, name));
                 if (resolver.getNodeCheckFlags(decl) & NodeCheckFlags.NeedsLoopOutParameter) {
                     const outParamName = createUniqueName("out_" + name.text);
                     loopOutParameters.push({ originalName: name, outParamName });
@@ -3081,9 +3091,8 @@ namespace ts {
         /**
          * Hooks node substitutions.
          *
+         * @param emitContext The context for the emitter.
          * @param node The node to substitute.
-         * @param isExpression A value indicating whether the node is to be used in an expression
-         *                     position.
          */
         function onSubstituteNode(emitContext: EmitContext, node: Node) {
             node = previousOnSubstituteNode(emitContext, node);
diff --git a/src/compiler/transformers/generators.ts b/src/compiler/transformers/generators.ts
index aaf9014c5cc6a..46c8ef5b7a32e 100644
--- a/src/compiler/transformers/generators.ts
+++ b/src/compiler/transformers/generators.ts
@@ -2369,7 +2369,7 @@ namespace ts {
                     labelExpressions = [];
                 }
 
-                const expression = <LiteralExpression>createSynthesizedNode(SyntaxKind.NumericLiteral);
+                const expression = createLiteral(-1);
                 if (labelExpressions[label] === undefined) {
                     labelExpressions[label] = [expression];
                 }
@@ -2380,7 +2380,7 @@ namespace ts {
                 return expression;
             }
 
-            return <OmittedExpression>createNode(SyntaxKind.OmittedExpression);
+            return createOmittedExpression();
         }
 
         /**
@@ -2596,7 +2596,7 @@ namespace ts {
                             /*asteriskToken*/ undefined,
                             /*name*/ undefined,
                             /*typeParameters*/ undefined,
-                            [createParameter(state)],
+                            [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, state)],
                             /*type*/ undefined,
                             createBlock(
                                 buildResult,
diff --git a/src/compiler/transformers/module/module.ts b/src/compiler/transformers/module/module.ts
index 1cca7a21777f5..f551f44dad168 100644
--- a/src/compiler/transformers/module/module.ts
+++ b/src/compiler/transformers/module/module.ts
@@ -91,7 +91,7 @@ namespace ts {
             addRange(statements, endLexicalEnvironment());
             addExportEqualsIfNeeded(statements, /*emitAsReturn*/ false);
 
-            const updated = updateSourceFile(node, statements);
+            const updated = updateSourceFileNode(node, createNodeArray(statements, node.statements));
             if (hasExportStarsToExportValues) {
                 setEmitFlags(updated, EmitFlags.EmitExportStar | getEmitFlags(node));
             }
@@ -156,7 +156,8 @@ namespace ts {
             // Create an updated SourceFile:
             //
             //     define(moduleName?, ["module1", "module2"], function ...
-            return updateSourceFile(node, [
+            return updateSourceFileNode(node, createNodeArray(
+                [
                 createStatement(
                     createCall(
                         define,
@@ -184,8 +185,8 @@ namespace ts {
                                 /*name*/ undefined,
                                 /*typeParameters*/ undefined,
                                 [
-                                    createParameter("require"),
-                                    createParameter("exports"),
+                                        createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "require"),
+                                        createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "exports"),
                                     ...importAliasNames
                                 ],
                                 /*type*/ undefined,
@@ -194,7 +195,9 @@ namespace ts {
                         ]
                     )
                 )
-            ]);
+                ],
+                /*location*/ node.statements)
+            );
         }
 
         /**
@@ -988,7 +991,7 @@ namespace ts {
         function createRequireCall(importNode: ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration) {
             const moduleName = getExternalModuleNameLiteral(importNode, currentSourceFile, host, resolver, compilerOptions);
             const args: Expression[] = [];
-            if (isDefined(moduleName)) {
+            if (moduleName) {
                 args.push(moduleName);
             }
 
@@ -1037,7 +1040,7 @@ namespace ts {
             for (const amdDependency of node.amdDependencies) {
                 if (amdDependency.name) {
                     aliasedModuleNames.push(createLiteral(amdDependency.path));
-                    importAliasNames.push(createParameter(amdDependency.name));
+                    importAliasNames.push(createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, amdDependency.name));
                 }
                 else {
                     unaliasedModuleNames.push(createLiteral(amdDependency.path));
@@ -1055,7 +1058,7 @@ namespace ts {
                     // This is so that when printer will not substitute the identifier
                     setEmitFlags(importAliasName, EmitFlags.NoSubstitution);
                     aliasedModuleNames.push(externalModuleName);
-                    importAliasNames.push(createParameter(importAliasName));
+                    importAliasNames.push(createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, importAliasName));
                 }
                 else {
                     unaliasedModuleNames.push(externalModuleName);
@@ -1064,11 +1067,5 @@ namespace ts {
 
             return { aliasedModuleNames, unaliasedModuleNames, importAliasNames };
         }
-
-        function updateSourceFile(node: SourceFile, statements: Statement[]) {
-            const updated = getMutableClone(node);
-            updated.statements = createNodeArray(statements, node.statements);
-            return updated;
-        }
     }
 }
diff --git a/src/compiler/transformers/module/system.ts b/src/compiler/transformers/module/system.ts
index 775d8fc34f9b5..d2903ba927aac 100644
--- a/src/compiler/transformers/module/system.ts
+++ b/src/compiler/transformers/module/system.ts
@@ -114,8 +114,8 @@ namespace ts {
                 /*name*/ undefined,
                 /*typeParameters*/ undefined,
                 [
-                    createParameter(exportFunctionForFile),
-                    createParameter(contextObjectForFile)
+                    createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, exportFunctionForFile),
+                    createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, contextObjectForFile)
                 ],
                 /*type*/ undefined,
                 setEmitFlags(
@@ -435,7 +435,7 @@ namespace ts {
                         /*asteriskToken*/ undefined,
                         /*name*/ undefined,
                         /*typeParameters*/ undefined,
-                        [createParameter(parameterName)],
+                        [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, parameterName)],
                         /*type*/ undefined,
                         createBlock(statements, /*location*/ undefined, /*multiLine*/ true)
                     )
@@ -771,7 +771,7 @@ namespace ts {
                 return createFor(
                     expressions.length
                         ? inlineExpressions(expressions)
-                        : <OmittedExpression>createSynthesizedNode(SyntaxKind.OmittedExpression),
+                        : createOmittedExpression(),
                     node.condition,
                     node.incrementor,
                     visitNode(node.statement, visitNestedNode, isStatement),
@@ -806,10 +806,12 @@ namespace ts {
         function visitForInStatement(node: ForInStatement): ForInStatement {
             const initializer = node.initializer;
             if (shouldHoistLoopInitializer(initializer)) {
-                const updated = getMutableClone(node);
-                updated.initializer = transformForBinding(<VariableDeclarationList>initializer);
-                updated.statement = visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock);
-                return updated;
+                return updateForIn(
+                    node,
+                    transformForBinding(<VariableDeclarationList>initializer),
+                    node.expression,
+                    visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock)
+                );
             }
             else {
                 return visitEachChild(node, visitNestedNode, context);
@@ -824,10 +826,12 @@ namespace ts {
         function visitForOfStatement(node: ForOfStatement): ForOfStatement {
             const initializer = node.initializer;
             if (shouldHoistLoopInitializer(initializer)) {
-                const updated = getMutableClone(node);
-                updated.initializer = transformForBinding(<VariableDeclarationList>initializer);
-                updated.statement = visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock);
-                return updated;
+                return updateForOf(
+                    node,
+                    transformForBinding(<VariableDeclarationList>initializer),
+                    node.expression,
+                    visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock)
+                );
             }
             else {
                 return visitEachChild(node, visitNestedNode, context);
@@ -840,14 +844,12 @@ namespace ts {
          * @param node The statement to visit.
          */
         function visitDoStatement(node: DoStatement) {
-            const statement = visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock);
-            if (statement !== node.statement) {
-                const updated = getMutableClone(node);
-                updated.statement = statement;
-                return updated;
+            return updateDo(
+                node,
+                visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock),
+                node.expression
+            );
             }
-            return node;
-        }
 
         /**
          * Visits the body of a WhileStatement to hoist declarations.
@@ -855,14 +857,12 @@ namespace ts {
          * @param node The statement to visit.
          */
         function visitWhileStatement(node: WhileStatement) {
-            const statement = visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock);
-            if (statement !== node.statement) {
-                const updated = getMutableClone(node);
-                updated.statement = statement;
-                return updated;
+            return updateWhile(
+                node,
+                node.expression,
+                visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock)
+            );
             }
-            return node;
-        }
 
         /**
          * Visits the body of a LabeledStatement to hoist declarations.
@@ -870,13 +870,11 @@ namespace ts {
          * @param node The statement to visit.
          */
         function visitLabeledStatement(node: LabeledStatement) {
-            const statement = visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock);
-            if (statement !== node.statement) {
-                const updated = getMutableClone(node);
-                updated.statement = statement;
-                return updated;
-            }
-            return node;
+            return updateLabel(
+                node,
+                node.label,
+                visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock)
+            );
         }
 
         /**
@@ -885,13 +883,11 @@ namespace ts {
          * @param node The statement to visit.
          */
         function visitWithStatement(node: WithStatement) {
-            const statement = visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock);
-            if (statement !== node.statement) {
-                const updated = getMutableClone(node);
-                updated.statement = statement;
-                return updated;
-            }
-            return node;
+            return updateWith(
+                node,
+                node.expression,
+                visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock)
+            );
         }
 
         /**
@@ -900,13 +896,11 @@ namespace ts {
          * @param node The statement to visit.
          */
         function visitSwitchStatement(node: SwitchStatement) {
-            const caseBlock = visitNode(node.caseBlock, visitNestedNode, isCaseBlock);
-            if (caseBlock !== node.caseBlock) {
-                const updated = getMutableClone(node);
-                updated.caseBlock = caseBlock;
-                return updated;
-            }
-            return node;
+            return updateSwitch(
+                node,
+                node.expression,
+                visitNode(node.caseBlock, visitNestedNode, isCaseBlock)
+            );
         }
 
         /**
@@ -915,13 +909,10 @@ namespace ts {
          * @param node The node to visit.
          */
         function visitCaseBlock(node: CaseBlock) {
-            const clauses = visitNodes(node.clauses, visitNestedNode, isCaseOrDefaultClause);
-            if (clauses !== node.clauses) {
-                const updated = getMutableClone(node);
-                updated.clauses = clauses;
-                return updated;
-            }
-            return node;
+            return updateCaseBlock(
+                node,
+                visitNodes(node.clauses, visitNestedNode, isCaseOrDefaultClause)
+            );
         }
 
         /**
@@ -930,13 +921,11 @@ namespace ts {
          * @param node The clause to visit.
          */
         function visitCaseClause(node: CaseClause) {
-            const statements = visitNodes(node.statements, visitNestedNode, isStatement);
-            if (statements !== node.statements) {
-                const updated = getMutableClone(node);
-                updated.statements = statements;
-                return updated;
-            }
-            return node;
+            return updateCaseClause(
+                node,
+                node.expression,
+                visitNodes(node.statements, visitNestedNode, isStatement)
+            );
         }
 
         /**
@@ -963,13 +952,11 @@ namespace ts {
          * @param node The clause to visit.
          */
         function visitCatchClause(node: CatchClause) {
-            const block = visitNode(node.block, visitNestedNode, isBlock);
-            if (block !== node.block) {
-                const updated = getMutableClone(node);
-                updated.block = block;
-                return updated;
-            }
-            return node;
+            return updateCatchClause(
+                node,
+                node.variableDeclaration,
+                visitNode(node.block, visitNestedNode, isBlock)
+            );
         }
 
         /**
@@ -1223,7 +1210,7 @@ namespace ts {
                     /*asteriskToken*/ undefined,
                     exportStarFunction,
                     /*typeParameters*/ undefined,
-                    [createParameter(m)],
+                    [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, m)],
                     /*type*/ undefined,
                     createBlock([
                         createVariableStatement(
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 1d930c3c21e6e..55e35106189ba 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -48,7 +48,7 @@ namespace ts {
         let currentNamespaceContainerName: Identifier;
         let currentScope: SourceFile | Block | ModuleBlock | CaseBlock;
         let currentScopeFirstDeclarationsOfName: Map<Node>;
-        let currentSourceFileExternalHelpersModuleName: Identifier;
+        let currentExternalHelpersModuleName: Identifier;
 
         /**
          * Keeps track of whether expression substitution has been enabled for specific edge cases.
@@ -475,16 +475,16 @@ namespace ts {
                     /*decorators*/ undefined,
                     /*modifiers*/ undefined,
                     createImportClause(/*name*/ undefined, createNamespaceImport(externalHelpersModuleName)),
-                    createLiteral(externalHelpersModuleNameText)
-                );
+                    createLiteral(externalHelpersModuleNameText));
+
                 externalHelpersModuleImport.parent = node;
                 externalHelpersModuleImport.flags &= ~NodeFlags.Synthesized;
                 statements.push(externalHelpersModuleImport);
 
-                currentSourceFileExternalHelpersModuleName = externalHelpersModuleName;
+                currentExternalHelpersModuleName = externalHelpersModuleName;
                 addRange(statements, visitNodes(node.statements, sourceElementVisitor, isStatement, statementOffset));
                 addRange(statements, endLexicalEnvironment());
-                currentSourceFileExternalHelpersModuleName = undefined;
+                currentExternalHelpersModuleName = undefined;
 
                 node = updateSourceFileNode(node, createNodeArray(statements, node.statements));
                 node.externalHelpersModuleName = externalHelpersModuleName;
@@ -614,9 +614,10 @@ namespace ts {
          * Transforms a decorated class declaration and appends the resulting statements. If
          * the class requires an alias to avoid issues with double-binding, the alias is returned.
          *
+         * @param statements A statement list to which to add the declaration.
          * @param node A ClassDeclaration node.
          * @param name The name of the class.
-         * @param hasExtendsClause A value indicating whether
+         * @param hasExtendsClause A value indicating whether the class has an extends clause.
          */
         function addClassDeclarationHeadWithDecorators(statements: Statement[], node: ClassDeclaration, name: Identifier, hasExtendsClause: boolean) {
             // When we emit an ES6 class that has a class decorator, we must tailor the
@@ -1454,7 +1455,7 @@ namespace ts {
                 : undefined;
 
             const helper = createDecorateHelper(
-                currentSourceFileExternalHelpersModuleName,
+                currentExternalHelpersModuleName,
                 decoratorExpressions,
                 prefix,
                 memberName,
@@ -1504,7 +1505,7 @@ namespace ts {
                 const expression = createAssignment(
                     decoratedClassAlias,
                     createDecorateHelper(
-                        currentSourceFileExternalHelpersModuleName,
+                        currentExternalHelpersModuleName,
                         decoratorExpressions,
                         getDeclarationName(node)
                     )
@@ -1528,7 +1529,7 @@ namespace ts {
                 const result = createAssignment(
                     getDeclarationName(node),
                     createDecorateHelper(
-                        currentSourceFileExternalHelpersModuleName,
+                        currentExternalHelpersModuleName,
                         decoratorExpressions,
                         getDeclarationName(node)
                     ),
@@ -1561,7 +1562,7 @@ namespace ts {
                 expressions = [];
                 for (const decorator of decorators) {
                     const helper = createParamHelper(
-                        currentSourceFileExternalHelpersModuleName,
+                        currentExternalHelpersModuleName,
                         transformDecorator(decorator),
                         parameterOffset,
                         /*location*/ decorator.expression);
@@ -1591,13 +1592,13 @@ namespace ts {
         function addOldTypeMetadata(node: Declaration, decoratorExpressions: Expression[]) {
             if (compilerOptions.emitDecoratorMetadata) {
                 if (shouldAddTypeMetadata(node)) {
-                    decoratorExpressions.push(createMetadataHelper(currentSourceFileExternalHelpersModuleName, "design:type", serializeTypeOfNode(node)));
+                    decoratorExpressions.push(createMetadataHelper(currentExternalHelpersModuleName, "design:type", serializeTypeOfNode(node)));
                 }
                 if (shouldAddParamTypesMetadata(node)) {
-                    decoratorExpressions.push(createMetadataHelper(currentSourceFileExternalHelpersModuleName, "design:paramtypes", serializeParameterTypesOfNode(node)));
+                    decoratorExpressions.push(createMetadataHelper(currentExternalHelpersModuleName, "design:paramtypes", serializeParameterTypesOfNode(node)));
                 }
                 if (shouldAddReturnTypeMetadata(node)) {
-                    decoratorExpressions.push(createMetadataHelper(currentSourceFileExternalHelpersModuleName, "design:returntype", serializeReturnTypeOfNode(node)));
+                    decoratorExpressions.push(createMetadataHelper(currentExternalHelpersModuleName, "design:returntype", serializeReturnTypeOfNode(node)));
                 }
             }
         }
@@ -1606,16 +1607,16 @@ namespace ts {
             if (compilerOptions.emitDecoratorMetadata) {
                 let properties: ObjectLiteralElementLike[];
                 if (shouldAddTypeMetadata(node)) {
-                    (properties || (properties = [])).push(createPropertyAssignment("type", createArrowFunction(/*modifiers*/ undefined, /*typeParameters*/ undefined, [], /*type*/ undefined, /*equalsGreaterThanToken*/ undefined, serializeTypeOfNode(node))));
+                    (properties || (properties = [])).push(createPropertyAssignment("type", createArrowFunction(/*modifiers*/ undefined, /*typeParameters*/ undefined, [], /*type*/ undefined, createToken(SyntaxKind.EqualsGreaterThanToken), serializeTypeOfNode(node))));
                 }
                 if (shouldAddParamTypesMetadata(node)) {
-                    (properties || (properties = [])).push(createPropertyAssignment("paramTypes", createArrowFunction(/*modifiers*/ undefined, /*typeParameters*/ undefined, [], /*type*/ undefined, /*equalsGreaterThanToken*/ undefined, serializeParameterTypesOfNode(node))));
+                    (properties || (properties = [])).push(createPropertyAssignment("paramTypes", createArrowFunction(/*modifiers*/ undefined, /*typeParameters*/ undefined, [], /*type*/ undefined, createToken(SyntaxKind.EqualsGreaterThanToken), serializeParameterTypesOfNode(node))));
                 }
                 if (shouldAddReturnTypeMetadata(node)) {
-                    (properties || (properties = [])).push(createPropertyAssignment("returnType", createArrowFunction(/*modifiers*/ undefined, /*typeParameters*/ undefined, [], /*type*/ undefined, /*equalsGreaterThanToken*/ undefined, serializeReturnTypeOfNode(node))));
+                    (properties || (properties = [])).push(createPropertyAssignment("returnType", createArrowFunction(/*modifiers*/ undefined, /*typeParameters*/ undefined, [], /*type*/ undefined, createToken(SyntaxKind.EqualsGreaterThanToken), serializeReturnTypeOfNode(node))));
                 }
                 if (properties) {
-                    decoratorExpressions.push(createMetadataHelper(currentSourceFileExternalHelpersModuleName, "design:typeinfo", createObjectLiteral(properties, /*location*/ undefined, /*multiLine*/ true)));
+                    decoratorExpressions.push(createMetadataHelper(currentExternalHelpersModuleName, "design:typeinfo", createObjectLiteral(properties, /*location*/ undefined, /*multiLine*/ true)));
                 }
             }
         }
@@ -2188,9 +2189,9 @@ namespace ts {
 
             // While we emit the source map for the node after skipping decorators and modifiers,
             // we need to emit the comments for the original range.
+            setOriginalNode(accessor, node);
             setCommentRange(accessor, node);
             setSourceMapRange(accessor, moveRangePastDecorators(node));
-            setOriginalNode(accessor, node);
 
             return accessor;
         }
@@ -2220,9 +2221,9 @@ namespace ts {
 
             // While we emit the source map for the node after skipping decorators and modifiers,
             // we need to emit the comments for the original range.
+            setOriginalNode(accessor, node);
             setCommentRange(accessor, node);
             setSourceMapRange(accessor, moveRangePastDecorators(node));
-            setOriginalNode(accessor, node);
 
             return accessor;
         }
@@ -2372,7 +2373,7 @@ namespace ts {
                 return undefined;
             }
 
-            const parameter = createParameterDeclaration(
+            const parameter = createParameter(
                 /*decorators*/ undefined,
                 /*modifiers*/ undefined,
                 node.dotDotDotToken,
@@ -2590,7 +2591,7 @@ namespace ts {
                         /*asteriskToken*/ undefined,
                         /*name*/ undefined,
                         /*typeParameters*/ undefined,
-                        [createParameter(parameterName)],
+                        [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, parameterName)],
                         /*type*/ undefined,
                         transformEnumBody(node, containerName)
                     ),
@@ -2758,7 +2759,7 @@ namespace ts {
                 ]
             );
 
-            setOriginalNode(statement, /*original*/ node);
+            setOriginalNode(statement, node);
 
             // Adjust the source map emit to match the old emitter.
             if (node.kind === SyntaxKind.EnumDeclaration) {
@@ -2862,7 +2863,7 @@ namespace ts {
                         /*asteriskToken*/ undefined,
                         /*name*/ undefined,
                         /*typeParameters*/ undefined,
-                        [createParameter(parameterName)],
+                        [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, parameterName)],
                         /*type*/ undefined,
                         transformModuleBody(node, containerName)
                     ),
@@ -3387,6 +3388,7 @@ namespace ts {
         /**
          * Hook for node emit.
          *
+         * @param emitContext A context hint for the emitter.
          * @param node The node to emit.
          * @param emit A callback used to emit the node in the printer.
          */
@@ -3409,9 +3411,8 @@ namespace ts {
         /**
          * Hooks node substitutions.
          *
+         * @param emitContext A context hint for the emitter.
          * @param node The node to substitute.
-         * @param isExpression A value indicating whether the node is to be used in an expression
-         *                     position.
          */
         function onSubstituteNode(emitContext: EmitContext, node: Node) {
             node = previousOnSubstituteNode(emitContext, node);
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 3840401daca60..d031188571db6 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -552,6 +552,14 @@ namespace ts {
         resolvedSymbol: Symbol;
     }
 
+    /*@internal*/
+    export interface GeneratedIdentifier extends Identifier {
+        autoGenerateKind: GeneratedIdentifierKind.Auto
+                        | GeneratedIdentifierKind.Loop
+                        | GeneratedIdentifierKind.Unique
+                        | GeneratedIdentifierKind.Node;
+    }
+
     export interface QualifiedName extends Node {
         kind: SyntaxKind.QualifiedName;
         left: EntityName;
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 7d4a144407462..c4e6712015cb9 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -3646,7 +3646,7 @@ namespace ts {
         return node.kind === SyntaxKind.Identifier;
     }
 
-    export function isGeneratedIdentifier(node: Node): boolean {
+    export function isGeneratedIdentifier(node: Node): node is GeneratedIdentifier {
         // Using `>` here catches both `GeneratedIdentifierKind.None` and `undefined`.
         return isIdentifier(node) && node.autoGenerateKind > GeneratedIdentifierKind.None;
     }
diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index 8dca78fec9794..0155e1b1511aa 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -692,7 +692,7 @@ namespace ts {
 
             // Signature elements
             case SyntaxKind.Parameter:
-                return updateParameterDeclaration(<ParameterDeclaration>node,
+                return updateParameter(<ParameterDeclaration>node,
                     visitNodes((<ParameterDeclaration>node).decorators, visitor, isDecorator),
                     visitNodes((<ParameterDeclaration>node).modifiers, visitor, isModifier),
                     visitNode((<ParameterDeclaration>node).name, visitor, isBindingName),

From bb8a3c41dbaf49008d375753233da11529a819f7 Mon Sep 17 00:00:00 2001
From: Ron Buckton <rbuckton@microsoft.com>
Date: Mon, 17 Oct 2016 00:43:02 -0700
Subject: [PATCH 054/224] Cleaned up emit of enum declaration

---
 src/compiler/transformers/module/module.ts    |  6 --
 src/compiler/transformers/module/system.ts    | 10 +--
 src/compiler/transformers/ts.ts               | 63 +++++++------------
 .../ModuleWithExportedAndNonExportedEnums.js  |  4 +-
 .../reference/amdImportAsPrimaryExpression.js |  4 +-
 .../amdImportNotAsPrimaryExpression.js        |  4 +-
 .../collisionExportsRequireAndEnum.js         | 24 +++----
 .../commentOnExportEnumDeclaration.js         |  4 +-
 .../commonJSImportNotAsPrimaryExpression.js   |  4 +-
 .../declFileTypeofInAnonymousType.js          |  4 +-
 .../declarationEmitNameConflicts2.js          |  4 +-
 .../declarationEmitNameConflicts3.js          |  4 +-
 .../disallowLineTerminatorBeforeArrow.js      |  4 +-
 .../reference/enumAssignmentCompat3.js        | 35 +++++------
 .../reference/enumAssignmentCompat4.js        |  8 +--
 .../reference/enumFromExternalModule.js       |  4 +-
 .../enumLiteralAssignableToEnumInsideUnion.js | 16 ++---
 tests/baselines/reference/enumMerging.js      | 30 +++++----
 .../baselines/reference/enumMergingErrors.js  | 60 +++++++++---------
 .../es5ModuleInternalNamedImports.js          |  4 +-
 .../es6ModuleConstEnumDeclaration2.js         |  8 +--
 .../reference/es6ModuleEnumDeclaration.js     |  8 +--
 .../es6ModuleInternalNamedImports.js          |  4 +-
 .../es6ModuleInternalNamedImports2.js         |  4 +-
 .../exportAssignmentAndDeclaration.js         |  4 +-
 tests/baselines/reference/exportCodeGen.js    |  4 +-
 .../reference/exportsAndImports3-amd.js       |  4 +-
 .../reference/exportsAndImports3-es6.js       |  4 +-
 .../baselines/reference/exportsAndImports3.js |  4 +-
 ...ericRecursiveImplicitConstructorErrors2.js |  4 +-
 .../baselines/reference/instantiatedModule.js |  4 +-
 .../reference/interfaceAssignmentCompat.js    |  4 +-
 .../baselines/reference/internalAliasEnum.js  |  4 +-
 ...nalAliasEnumInsideLocalModuleWithExport.js |  4 +-
 ...AliasEnumInsideLocalModuleWithoutExport.js |  4 +-
 ...sideLocalModuleWithoutExportAccessError.js |  4 +-
 ...AliasEnumInsideTopLevelModuleWithExport.js |  4 +-
 ...asEnumInsideTopLevelModuleWithoutExport.js |  4 +-
 .../reference/localImportNameVsGlobalName.js  |  4 +-
 .../reference/mergeWithImportedType.js        |  4 +-
 .../reference/mergedDeclarations3.js          |  4 +-
 .../mergedModuleDeclarationCodeGen5.js        |  4 +-
 .../baselines/reference/moduleCodeGenTest5.js |  4 +-
 .../reference/moduleDuplicateIdentifiers.js   |  6 +-
 ...duleSameValueDuplicateExportedBindings2.js |  4 +-
 .../reference/moduleVisibilityTest1.js        |  4 +-
 .../moduleWithStatementsOfEveryKind.js        |  4 +-
 tests/baselines/reference/nameCollision.js    |  4 +-
 tests/baselines/reference/parserEnum1.js      |  4 +-
 tests/baselines/reference/parserEnum2.js      |  4 +-
 tests/baselines/reference/parserEnum3.js      |  4 +-
 tests/baselines/reference/parserEnum4.js      |  4 +-
 .../baselines/reference/parserRealSource10.js | 16 ++---
 .../baselines/reference/parserRealSource14.js |  4 +-
 .../baselines/reference/parserRealSource2.js  | 56 ++++++++---------
 .../baselines/reference/parserRealSource3.js  |  4 +-
 ...yLocalInternalReferenceImportWithExport.js |  8 +--
 ...calInternalReferenceImportWithoutExport.js |  8 +--
 ...pLevelInternalReferenceImportWithExport.js |  8 +--
 ...velInternalReferenceImportWithoutExport.js |  8 +--
 tests/baselines/reference/scannerEnum1.js     |  4 +-
 ...stemModuleConstEnumsSeparateCompilation.js |  4 +-
 .../systemModuleDeclarationMerging.js         |  2 +-
 .../systemModuleNonTopLevelModuleMembers.js   |  6 +-
 .../reference/typeofAnExportedType.js         |  4 +-
 65 files changed, 266 insertions(+), 300 deletions(-)

diff --git a/src/compiler/transformers/module/module.ts b/src/compiler/transformers/module/module.ts
index f551f44dad168..51b03b43c94da 100644
--- a/src/compiler/transformers/module/module.ts
+++ b/src/compiler/transformers/module/module.ts
@@ -792,12 +792,6 @@ namespace ts {
         function visitExpressionStatementForEnumOrNamespaceDeclaration(node: ExpressionStatement, original: EnumDeclaration | ModuleDeclaration): VisitResult<Statement> {
             const statements: Statement[] = [node];
 
-            // Preserve old behavior for enums in which a variable statement is emitted after the body itself.
-            if (hasModifier(original, ModifierFlags.Export) &&
-                original.kind === SyntaxKind.EnumDeclaration &&
-                isFirstDeclarationOfKind(original, SyntaxKind.EnumDeclaration)) {
-                addVarForExportedEnumOrNamespaceDeclaration(statements, original);
-            }
 
             addExportMemberAssignments(statements, <Identifier>original.name);
 
diff --git a/src/compiler/transformers/module/system.ts b/src/compiler/transformers/module/system.ts
index d2903ba927aac..acd25a41a090f 100644
--- a/src/compiler/transformers/module/system.ts
+++ b/src/compiler/transformers/module/system.ts
@@ -692,12 +692,6 @@ namespace ts {
             const originalNode = getOriginalNode(node);
             if ((originalNode.kind === SyntaxKind.ModuleDeclaration || originalNode.kind === SyntaxKind.EnumDeclaration) && hasModifier(originalNode, ModifierFlags.Export)) {
                 const name = getDeclarationName(<ModuleDeclaration | EnumDeclaration>originalNode);
-                // We only need to hoistVariableDeclaration for EnumDeclaration
-                // as ModuleDeclaration is already hoisted when the transformer call visitVariableStatement
-                // which then call transformsVariable for each declaration in declarationList
-                if (originalNode.kind === SyntaxKind.EnumDeclaration) {
-                    hoistVariableDeclaration(name);
-                }
                 return [
                     node,
                     createExportStatement(name, name)
@@ -849,7 +843,7 @@ namespace ts {
                 visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock),
                 node.expression
             );
-            }
+        }
 
         /**
          * Visits the body of a WhileStatement to hoist declarations.
@@ -862,7 +856,7 @@ namespace ts {
                 node.expression,
                 visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock)
             );
-            }
+        }
 
         /**
          * Visits the body of a LabeledStatement to hoist declarations.
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 55e35106189ba..fdb3f7b208d9a 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -2517,29 +2517,6 @@ namespace ts {
                 || compilerOptions.isolatedModules;
         }
 
-        function shouldEmitVarForEnumDeclaration(node: EnumDeclaration | ModuleDeclaration) {
-            return isFirstEmittedDeclarationInScope(node)
-                && (!hasModifier(node, ModifierFlags.Export)
-                    || isES6ExportedDeclaration(node));
-        }
-
-
-        /*
-         * Adds a trailing VariableStatement for an enum or module declaration.
-         */
-        function addVarForEnumExportedFromNamespace(statements: Statement[], node: EnumDeclaration | ModuleDeclaration) {
-            const statement = createVariableStatement(
-                /*modifiers*/ undefined,
-                [createVariableDeclaration(
-                    getDeclarationName(node),
-                    /*type*/ undefined,
-                    getExportName(node)
-                )]
-            );
-            setSourceMapRange(statement, node);
-            statements.push(statement);
-        }
-
         /**
          * Visits an enum declaration.
          *
@@ -2562,7 +2539,7 @@ namespace ts {
             // a leading variable declaration, we should not emit leading comments for the
             // enum body.
             recordEmittedDeclarationInScope(node);
-            if (shouldEmitVarForEnumDeclaration(node)) {
+            if (isFirstEmittedDeclarationInScope(node)) {
                 addVarForEnumOrModuleDeclaration(statements, node);
 
                 // We should still emit the comments if we are emitting a system module.
@@ -2580,6 +2557,25 @@ namespace ts {
             // `exportName` is the expression used within this node's container for any exported references.
             const exportName = getExportName(node);
 
+            //  x || (x = {})
+            //  exports.x || (exports.x = {})
+            let moduleArg =
+                createLogicalOr(
+                    exportName,
+                    createAssignment(
+                        exportName,
+                        createObjectLiteral()
+                    )
+                );
+
+            if (hasModifier(node, ModifierFlags.Export) && !isES6ExportedDeclaration(node)) {
+                // `localName` is the expression used within this node's containing scope for any local references.
+                const localName = getLocalName(node);
+
+                //  x = (exports.x || (exports.x = {}))
+                moduleArg = createAssignment(localName, moduleArg);
+            }
+
             //  (function (x) {
             //      x[x["y"] = 0] = "y";
             //      ...
@@ -2596,13 +2592,7 @@ namespace ts {
                         transformEnumBody(node, containerName)
                     ),
                     /*typeArguments*/ undefined,
-                    [createLogicalOr(
-                        exportName,
-                        createAssignment(
-                            exportName,
-                            createObjectLiteral()
-                        )
-                    )]
+                    [moduleArg]
                 ),
                 /*location*/ node
             );
@@ -2610,11 +2600,6 @@ namespace ts {
             setOriginalNode(enumStatement, node);
             setEmitFlags(enumStatement, emitFlags);
             statements.push(enumStatement);
-
-            if (isNamespaceExport(node)) {
-                addVarForEnumExportedFromNamespace(statements, node);
-            }
-
             return statements;
         }
 
@@ -2739,10 +2724,6 @@ namespace ts {
             return false;
         }
 
-        function shouldEmitVarForModuleDeclaration(node: ModuleDeclaration) {
-            return isFirstEmittedDeclarationInScope(node);
-        }
-
         /**
          * Adds a leading VariableStatement for a enum or module declaration.
          */
@@ -2817,7 +2798,7 @@ namespace ts {
             // a leading variable declaration, we should not emit leading comments for the
             // module body.
             recordEmittedDeclarationInScope(node);
-            if (shouldEmitVarForModuleDeclaration(node)) {
+            if (isFirstEmittedDeclarationInScope(node)) {
                 addVarForEnumOrModuleDeclaration(statements, node);
                 // We should still emit the comments if we are emitting a system module.
                 if (moduleKind !== ModuleKind.System || currentScope !== currentSourceFile) {
diff --git a/tests/baselines/reference/ModuleWithExportedAndNonExportedEnums.js b/tests/baselines/reference/ModuleWithExportedAndNonExportedEnums.js
index 3cd522d3c2c2f..713d2ac7f1870 100644
--- a/tests/baselines/reference/ModuleWithExportedAndNonExportedEnums.js
+++ b/tests/baselines/reference/ModuleWithExportedAndNonExportedEnums.js
@@ -14,11 +14,11 @@ var b = A.Day.Monday;
 //// [ModuleWithExportedAndNonExportedEnums.js]
 var A;
 (function (A) {
+    var Color;
     (function (Color) {
         Color[Color["Red"] = 0] = "Red";
         Color[Color["Blue"] = 1] = "Blue";
-    })(A.Color || (A.Color = {}));
-    var Color = A.Color;
+    })(Color = A.Color || (A.Color = {}));
     var Day;
     (function (Day) {
         Day[Day["Monday"] = 0] = "Monday";
diff --git a/tests/baselines/reference/amdImportAsPrimaryExpression.js b/tests/baselines/reference/amdImportAsPrimaryExpression.js
index 1281b7f7f4757..3c2e9c041fac0 100644
--- a/tests/baselines/reference/amdImportAsPrimaryExpression.js
+++ b/tests/baselines/reference/amdImportAsPrimaryExpression.js
@@ -15,12 +15,12 @@ if(foo.E1.A === 0){
 //// [foo_0.js]
 define(["require", "exports"], function (require, exports) {
     "use strict";
+    var E1;
     (function (E1) {
         E1[E1["A"] = 0] = "A";
         E1[E1["B"] = 1] = "B";
         E1[E1["C"] = 2] = "C";
-    })(exports.E1 || (exports.E1 = {}));
-    var E1 = exports.E1;
+    })(E1 = exports.E1 || (exports.E1 = {}));
 });
 //// [foo_1.js]
 define(["require", "exports", "./foo_0"], function (require, exports, foo) {
diff --git a/tests/baselines/reference/amdImportNotAsPrimaryExpression.js b/tests/baselines/reference/amdImportNotAsPrimaryExpression.js
index b8e9f5346b07e..efd1c2aa909fa 100644
--- a/tests/baselines/reference/amdImportNotAsPrimaryExpression.js
+++ b/tests/baselines/reference/amdImportNotAsPrimaryExpression.js
@@ -42,12 +42,12 @@ define(["require", "exports"], function (require, exports) {
     }());
     exports.C1 = C1;
     C1.s1 = true;
+    var E1;
     (function (E1) {
         E1[E1["A"] = 0] = "A";
         E1[E1["B"] = 1] = "B";
         E1[E1["C"] = 2] = "C";
-    })(exports.E1 || (exports.E1 = {}));
-    var E1 = exports.E1;
+    })(E1 = exports.E1 || (exports.E1 = {}));
 });
 //// [foo_1.js]
 define(["require", "exports"], function (require, exports) {
diff --git a/tests/baselines/reference/collisionExportsRequireAndEnum.js b/tests/baselines/reference/collisionExportsRequireAndEnum.js
index 3935ee312fb73..47d127e8a67f7 100644
--- a/tests/baselines/reference/collisionExportsRequireAndEnum.js
+++ b/tests/baselines/reference/collisionExportsRequireAndEnum.js
@@ -63,16 +63,16 @@ module m4 {
 //// [collisionExportsRequireAndEnum_externalmodule.js]
 define(["require", "exports"], function (require, exports) {
     "use strict";
+    var require;
     (function (require) {
         require[require["_thisVal1"] = 0] = "_thisVal1";
         require[require["_thisVal2"] = 1] = "_thisVal2";
-    })(exports.require || (exports.require = {}));
-    var require = exports.require;
+    })(require = exports.require || (exports.require = {}));
+    var exports;
     (function (exports) {
         exports[exports["_thisVal1"] = 0] = "_thisVal1";
         exports[exports["_thisVal2"] = 1] = "_thisVal2";
-    })(exports.exports || (exports.exports = {}));
-    var exports = exports.exports;
+    })(exports = exports.exports || (exports.exports = {}));
     var m1;
     (function (m1) {
         var require;
@@ -88,16 +88,16 @@ define(["require", "exports"], function (require, exports) {
     })(m1 || (m1 = {}));
     var m2;
     (function (m2) {
+        var require;
         (function (require) {
             require[require["_thisVal1"] = 0] = "_thisVal1";
             require[require["_thisVal2"] = 1] = "_thisVal2";
-        })(m2.require || (m2.require = {}));
-        var require = m2.require;
+        })(require = m2.require || (m2.require = {}));
+        var exports;
         (function (exports) {
             exports[exports["_thisVal1"] = 0] = "_thisVal1";
             exports[exports["_thisVal2"] = 1] = "_thisVal2";
-        })(m2.exports || (m2.exports = {}));
-        var exports = m2.exports;
+        })(exports = m2.exports || (m2.exports = {}));
     })(m2 || (m2 = {}));
 });
 //// [collisionExportsRequireAndEnum_globalFile.js]
@@ -126,14 +126,14 @@ var m3;
 })(m3 || (m3 = {}));
 var m4;
 (function (m4) {
+    var require;
     (function (require) {
         require[require["_thisVal1"] = 0] = "_thisVal1";
         require[require["_thisVal2"] = 1] = "_thisVal2";
-    })(m4.require || (m4.require = {}));
-    var require = m4.require;
+    })(require = m4.require || (m4.require = {}));
+    var exports;
     (function (exports) {
         exports[exports["_thisVal1"] = 0] = "_thisVal1";
         exports[exports["_thisVal2"] = 1] = "_thisVal2";
-    })(m4.exports || (m4.exports = {}));
-    var exports = m4.exports;
+    })(exports = m4.exports || (m4.exports = {}));
 })(m4 || (m4 = {}));
diff --git a/tests/baselines/reference/commentOnExportEnumDeclaration.js b/tests/baselines/reference/commentOnExportEnumDeclaration.js
index 6ded51456d881..61307b95b1c91 100644
--- a/tests/baselines/reference/commentOnExportEnumDeclaration.js
+++ b/tests/baselines/reference/commentOnExportEnumDeclaration.js
@@ -11,9 +11,9 @@ export enum Color {
 /**
  * comment
  */
+var Color;
 (function (Color) {
     Color[Color["r"] = 0] = "r";
     Color[Color["g"] = 1] = "g";
     Color[Color["b"] = 2] = "b";
-})(exports.Color || (exports.Color = {}));
-var Color = exports.Color;
+})(Color = exports.Color || (exports.Color = {}));
diff --git a/tests/baselines/reference/commonJSImportNotAsPrimaryExpression.js b/tests/baselines/reference/commonJSImportNotAsPrimaryExpression.js
index e7496f3445fc9..a66d04a2ddedb 100644
--- a/tests/baselines/reference/commonJSImportNotAsPrimaryExpression.js
+++ b/tests/baselines/reference/commonJSImportNotAsPrimaryExpression.js
@@ -41,12 +41,12 @@ var C1 = (function () {
 }());
 exports.C1 = C1;
 C1.s1 = true;
+var E1;
 (function (E1) {
     E1[E1["A"] = 0] = "A";
     E1[E1["B"] = 1] = "B";
     E1[E1["C"] = 2] = "C";
-})(exports.E1 || (exports.E1 = {}));
-var E1 = exports.E1;
+})(E1 = exports.E1 || (exports.E1 = {}));
 //// [foo_1.js]
 "use strict";
 var i;
diff --git a/tests/baselines/reference/declFileTypeofInAnonymousType.js b/tests/baselines/reference/declFileTypeofInAnonymousType.js
index 68db3d120cdfa..656cd49ebfaea 100644
--- a/tests/baselines/reference/declFileTypeofInAnonymousType.js
+++ b/tests/baselines/reference/declFileTypeofInAnonymousType.js
@@ -31,12 +31,12 @@ var m1;
         return c;
     }());
     m1.c = c;
+    var e;
     (function (e) {
         e[e["weekday"] = 0] = "weekday";
         e[e["weekend"] = 1] = "weekend";
         e[e["holiday"] = 2] = "holiday";
-    })(m1.e || (m1.e = {}));
-    var e = m1.e;
+    })(e = m1.e || (m1.e = {}));
 })(m1 || (m1 = {}));
 var a;
 var b = {
diff --git a/tests/baselines/reference/declarationEmitNameConflicts2.js b/tests/baselines/reference/declarationEmitNameConflicts2.js
index 41dcec4690f2a..05529fbf5befe 100644
--- a/tests/baselines/reference/declarationEmitNameConflicts2.js
+++ b/tests/baselines/reference/declarationEmitNameConflicts2.js
@@ -33,9 +33,9 @@ var X;
             var M;
             (function (M) {
             })(M = base.M || (base.M = {}));
+            var E;
             (function (E) {
-            })(base.E || (base.E = {}));
-            var E = base.E;
+            })(E = base.E || (base.E = {}));
         })(base = Y.base || (Y.base = {}));
     })(Y = X.Y || (X.Y = {}));
 })(X || (X = {}));
diff --git a/tests/baselines/reference/declarationEmitNameConflicts3.js b/tests/baselines/reference/declarationEmitNameConflicts3.js
index b0a87e6448338..ffcfead83bf0f 100644
--- a/tests/baselines/reference/declarationEmitNameConflicts3.js
+++ b/tests/baselines/reference/declarationEmitNameConflicts3.js
@@ -68,10 +68,10 @@ var M;
             return E;
         }(C));
         P.E = E;
+        var D;
         (function (D) {
             D[D["f"] = 0] = "f";
-        })(P.D || (P.D = {}));
-        var D = P.D;
+        })(D = P.D || (P.D = {}));
         P.w = M.D.f; // error, should be typeof M.D.f
         P.x = M.C.f; // error, should be typeof M.C.f
         P.x = M.E.f; // error, should be typeof M.E.f
diff --git a/tests/baselines/reference/disallowLineTerminatorBeforeArrow.js b/tests/baselines/reference/disallowLineTerminatorBeforeArrow.js
index 1044146ccd0c2..0c6b98def4fd1 100644
--- a/tests/baselines/reference/disallowLineTerminatorBeforeArrow.js
+++ b/tests/baselines/reference/disallowLineTerminatorBeforeArrow.js
@@ -138,9 +138,9 @@ var m;
         }
         return City;
     }());
+    var Enum;
     (function (Enum) {
         Enum[Enum["claw"] = (function () { return 10; })()] = "claw";
-    })(m.Enum || (m.Enum = {}));
-    var Enum = m.Enum;
+    })(Enum = m.Enum || (m.Enum = {}));
     m.v = function (x) { return new City(Enum.claw); };
 })(m || (m = {}));
diff --git a/tests/baselines/reference/enumAssignmentCompat3.js b/tests/baselines/reference/enumAssignmentCompat3.js
index 62f05c18b5fff..accaaa7a99e20 100644
--- a/tests/baselines/reference/enumAssignmentCompat3.js
+++ b/tests/baselines/reference/enumAssignmentCompat3.js
@@ -92,78 +92,77 @@ merged2 = abc; // ok
 //// [enumAssignmentCompat3.js]
 var First;
 (function (First) {
+    var E;
     (function (E) {
         E[E["a"] = 0] = "a";
         E[E["b"] = 1] = "b";
         E[E["c"] = 2] = "c";
-    })(First.E || (First.E = {}));
-    var E = First.E;
+    })(E = First.E || (First.E = {}));
 })(First || (First = {}));
 var Abc;
 (function (Abc) {
+    var E;
     (function (E) {
         E[E["a"] = 0] = "a";
         E[E["b"] = 1] = "b";
         E[E["c"] = 2] = "c";
-    })(Abc.E || (Abc.E = {}));
-    var E = Abc.E;
+    })(E = Abc.E || (Abc.E = {}));
+    var Nope;
     (function (Nope) {
         Nope[Nope["a"] = 0] = "a";
         Nope[Nope["b"] = 1] = "b";
         Nope[Nope["c"] = 2] = "c";
-    })(Abc.Nope || (Abc.Nope = {}));
-    var Nope = Abc.Nope;
+    })(Nope = Abc.Nope || (Abc.Nope = {}));
 })(Abc || (Abc = {}));
 var Abcd;
 (function (Abcd) {
+    var E;
     (function (E) {
         E[E["a"] = 0] = "a";
         E[E["b"] = 1] = "b";
         E[E["c"] = 2] = "c";
         E[E["d"] = 3] = "d";
-    })(Abcd.E || (Abcd.E = {}));
-    var E = Abcd.E;
+    })(E = Abcd.E || (Abcd.E = {}));
 })(Abcd || (Abcd = {}));
 var Ab;
 (function (Ab) {
+    var E;
     (function (E) {
         E[E["a"] = 0] = "a";
         E[E["b"] = 1] = "b";
-    })(Ab.E || (Ab.E = {}));
-    var E = Ab.E;
+    })(E = Ab.E || (Ab.E = {}));
 })(Ab || (Ab = {}));
 var Cd;
 (function (Cd) {
+    var E;
     (function (E) {
         E[E["c"] = 0] = "c";
         E[E["d"] = 1] = "d";
-    })(Cd.E || (Cd.E = {}));
-    var E = Cd.E;
+    })(E = Cd.E || (Cd.E = {}));
 })(Cd || (Cd = {}));
 var Decl;
 (function (Decl) {
 })(Decl || (Decl = {}));
 var Merged;
 (function (Merged) {
+    var E;
     (function (E) {
         E[E["a"] = 0] = "a";
         E[E["b"] = 1] = "b";
-    })(Merged.E || (Merged.E = {}));
-    var E = Merged.E;
+    })(E = Merged.E || (Merged.E = {}));
     (function (E) {
         E[E["c"] = 3] = "c";
         E[E["d"] = 4] = "d";
-    })(Merged.E || (Merged.E = {}));
-    var E = Merged.E;
+    })(E = Merged.E || (Merged.E = {}));
 })(Merged || (Merged = {}));
 var Merged2;
 (function (Merged2) {
+    var E;
     (function (E) {
         E[E["a"] = 0] = "a";
         E[E["b"] = 1] = "b";
         E[E["c"] = 2] = "c";
-    })(Merged2.E || (Merged2.E = {}));
-    var E = Merged2.E;
+    })(E = Merged2.E || (Merged2.E = {}));
     (function (E) {
         E.d = 5;
     })(E = Merged2.E || (Merged2.E = {}));
diff --git a/tests/baselines/reference/enumAssignmentCompat4.js b/tests/baselines/reference/enumAssignmentCompat4.js
index ad28324ce0fe1..35bc9319ce9c3 100644
--- a/tests/baselines/reference/enumAssignmentCompat4.js
+++ b/tests/baselines/reference/enumAssignmentCompat4.js
@@ -26,20 +26,20 @@ let broken = [
 //// [enumAssignmentCompat4.js]
 var M;
 (function (M) {
+    var MyEnum;
     (function (MyEnum) {
         MyEnum[MyEnum["BAR"] = 0] = "BAR";
-    })(M.MyEnum || (M.MyEnum = {}));
-    var MyEnum = M.MyEnum;
+    })(MyEnum = M.MyEnum || (M.MyEnum = {}));
     M.object2 = {
         foo: MyEnum.BAR
     };
 })(M || (M = {}));
 var N;
 (function (N) {
+    var MyEnum;
     (function (MyEnum) {
         MyEnum[MyEnum["FOO"] = 0] = "FOO";
-    })(N.MyEnum || (N.MyEnum = {}));
-    var MyEnum = N.MyEnum;
+    })(MyEnum = N.MyEnum || (N.MyEnum = {}));
     ;
     N.object1 = {
         foo: MyEnum.FOO
diff --git a/tests/baselines/reference/enumFromExternalModule.js b/tests/baselines/reference/enumFromExternalModule.js
index 77f0e643969cc..a6e9f6b60762e 100644
--- a/tests/baselines/reference/enumFromExternalModule.js
+++ b/tests/baselines/reference/enumFromExternalModule.js
@@ -12,10 +12,10 @@ var x = f.Mode.Open;
 
 //// [enumFromExternalModule_0.js]
 "use strict";
+var Mode;
 (function (Mode) {
     Mode[Mode["Open"] = 0] = "Open";
-})(exports.Mode || (exports.Mode = {}));
-var Mode = exports.Mode;
+})(Mode = exports.Mode || (exports.Mode = {}));
 //// [enumFromExternalModule_1.js]
 "use strict";
 ///<reference path='enumFromExternalModule_0.ts'/>
diff --git a/tests/baselines/reference/enumLiteralAssignableToEnumInsideUnion.js b/tests/baselines/reference/enumLiteralAssignableToEnumInsideUnion.js
index 8786745a5044d..077e5690dd84d 100644
--- a/tests/baselines/reference/enumLiteralAssignableToEnumInsideUnion.js
+++ b/tests/baselines/reference/enumLiteralAssignableToEnumInsideUnion.js
@@ -32,35 +32,35 @@ const e5: Ka.Foo | boolean = Z.Foo.A; // ok
 //// [enumLiteralAssignableToEnumInsideUnion.js]
 var X;
 (function (X) {
+    var Foo;
     (function (Foo) {
         Foo[Foo["A"] = 0] = "A";
         Foo[Foo["B"] = 1] = "B";
-    })(X.Foo || (X.Foo = {}));
-    var Foo = X.Foo;
+    })(Foo = X.Foo || (X.Foo = {}));
 })(X || (X = {}));
 var Y;
 (function (Y) {
+    var Foo;
     (function (Foo) {
         Foo[Foo["A"] = 0] = "A";
         Foo[Foo["B"] = 1] = "B";
-    })(Y.Foo || (Y.Foo = {}));
-    var Foo = Y.Foo;
+    })(Foo = Y.Foo || (Y.Foo = {}));
 })(Y || (Y = {}));
 var Z;
 (function (Z) {
+    var Foo;
     (function (Foo) {
         Foo[Foo["A"] = 2] = "A";
         Foo[Foo["B"] = 4] = "B";
-    })(Z.Foo || (Z.Foo = {}));
-    var Foo = Z.Foo;
+    })(Foo = Z.Foo || (Z.Foo = {}));
 })(Z || (Z = {}));
 var Ka;
 (function (Ka) {
+    var Foo;
     (function (Foo) {
         Foo[Foo["A"] = 1024] = "A";
         Foo[Foo["B"] = 2048] = "B";
-    })(Ka.Foo || (Ka.Foo = {}));
-    var Foo = Ka.Foo;
+    })(Foo = Ka.Foo || (Ka.Foo = {}));
 })(Ka || (Ka = {}));
 var e0 = Y.Foo.A; // ok
 var e1 = Z.Foo.A; // not legal, Z is computed
diff --git a/tests/baselines/reference/enumMerging.js b/tests/baselines/reference/enumMerging.js
index d830b03cac997..c3fa7fffeb30e 100644
--- a/tests/baselines/reference/enumMerging.js
+++ b/tests/baselines/reference/enumMerging.js
@@ -82,35 +82,33 @@ var M1;
         EImpl1[EImpl1["E"] = 2] = "E";
         EImpl1[EImpl1["F"] = 3] = "F";
     })(EImpl1 || (EImpl1 = {}));
+    var EConst1;
     (function (EConst1) {
         EConst1[EConst1["A"] = 3] = "A";
         EConst1[EConst1["B"] = 2] = "B";
         EConst1[EConst1["C"] = 1] = "C";
-    })(M1.EConst1 || (M1.EConst1 = {}));
-    var EConst1 = M1.EConst1;
+    })(EConst1 = M1.EConst1 || (M1.EConst1 = {}));
     (function (EConst1) {
         EConst1[EConst1["D"] = 7] = "D";
         EConst1[EConst1["E"] = 9] = "E";
         EConst1[EConst1["F"] = 8] = "F";
-    })(M1.EConst1 || (M1.EConst1 = {}));
-    var EConst1 = M1.EConst1;
+    })(EConst1 = M1.EConst1 || (M1.EConst1 = {}));
     var x = [EConst1.A, EConst1.B, EConst1.C, EConst1.D, EConst1.E, EConst1.F];
 })(M1 || (M1 = {}));
 // Enum with only computed members across 2 declarations with the same root module 
 var M2;
 (function (M2) {
+    var EComp2;
     (function (EComp2) {
         EComp2[EComp2["A"] = 'foo'.length] = "A";
         EComp2[EComp2["B"] = 'foo'.length] = "B";
         EComp2[EComp2["C"] = 'foo'.length] = "C";
-    })(M2.EComp2 || (M2.EComp2 = {}));
-    var EComp2 = M2.EComp2;
+    })(EComp2 = M2.EComp2 || (M2.EComp2 = {}));
     (function (EComp2) {
         EComp2[EComp2["D"] = 'foo'.length] = "D";
         EComp2[EComp2["E"] = 'foo'.length] = "E";
         EComp2[EComp2["F"] = 'foo'.length] = "F";
-    })(M2.EComp2 || (M2.EComp2 = {}));
-    var EComp2 = M2.EComp2;
+    })(EComp2 = M2.EComp2 || (M2.EComp2 = {}));
     var x = [EComp2.A, EComp2.B, EComp2.C, EComp2.D, EComp2.E, EComp2.F];
 })(M2 || (M2 = {}));
 // Enum with initializer in only one of two declarations with constant members with the same root module
@@ -130,41 +128,41 @@ var M3;
 // Enums with same name but different root module
 var M4;
 (function (M4) {
+    var Color;
     (function (Color) {
         Color[Color["Red"] = 0] = "Red";
         Color[Color["Green"] = 1] = "Green";
         Color[Color["Blue"] = 2] = "Blue";
-    })(M4.Color || (M4.Color = {}));
-    var Color = M4.Color;
+    })(Color = M4.Color || (M4.Color = {}));
 })(M4 || (M4 = {}));
 var M5;
 (function (M5) {
+    var Color;
     (function (Color) {
         Color[Color["Red"] = 0] = "Red";
         Color[Color["Green"] = 1] = "Green";
         Color[Color["Blue"] = 2] = "Blue";
-    })(M5.Color || (M5.Color = {}));
-    var Color = M5.Color;
+    })(Color = M5.Color || (M5.Color = {}));
 })(M5 || (M5 = {}));
 var M6;
 (function (M6) {
     var A;
     (function (A) {
+        var Color;
         (function (Color) {
             Color[Color["Red"] = 0] = "Red";
             Color[Color["Green"] = 1] = "Green";
             Color[Color["Blue"] = 2] = "Blue";
-        })(A.Color || (A.Color = {}));
-        var Color = A.Color;
+        })(Color = A.Color || (A.Color = {}));
     })(A = M6.A || (M6.A = {}));
 })(M6 || (M6 = {}));
 (function (M6) {
     var A;
     (function (A) {
+        var Color;
         (function (Color) {
             Color[Color["Yellow"] = 1] = "Yellow";
-        })(A.Color || (A.Color = {}));
-        var Color = A.Color;
+        })(Color = A.Color || (A.Color = {}));
     })(A = M6.A || (M6.A = {}));
     var t = A.Color.Yellow;
     t = A.Color.Red;
diff --git a/tests/baselines/reference/enumMergingErrors.js b/tests/baselines/reference/enumMergingErrors.js
index c9b4aaef75417..05482f48377d9 100644
--- a/tests/baselines/reference/enumMergingErrors.js
+++ b/tests/baselines/reference/enumMergingErrors.js
@@ -46,84 +46,84 @@ module M2 {
 // Enum with constant, computed, constant members split across 3 declarations with the same root module
 var M;
 (function (M) {
+    var E1;
     (function (E1) {
         E1[E1["A"] = 0] = "A";
-    })(M.E1 || (M.E1 = {}));
-    var E1 = M.E1;
+    })(E1 = M.E1 || (M.E1 = {}));
+    var E2;
     (function (E2) {
         E2[E2["C"] = 0] = "C";
-    })(M.E2 || (M.E2 = {}));
-    var E2 = M.E2;
+    })(E2 = M.E2 || (M.E2 = {}));
+    var E3;
     (function (E3) {
         E3[E3["A"] = 0] = "A";
-    })(M.E3 || (M.E3 = {}));
-    var E3 = M.E3;
+    })(E3 = M.E3 || (M.E3 = {}));
 })(M || (M = {}));
 (function (M) {
+    var E1;
     (function (E1) {
         E1[E1["B"] = 'foo'.length] = "B";
-    })(M.E1 || (M.E1 = {}));
-    var E1 = M.E1;
+    })(E1 = M.E1 || (M.E1 = {}));
+    var E2;
     (function (E2) {
         E2[E2["B"] = 'foo'.length] = "B";
-    })(M.E2 || (M.E2 = {}));
-    var E2 = M.E2;
+    })(E2 = M.E2 || (M.E2 = {}));
+    var E3;
     (function (E3) {
         E3[E3["C"] = 0] = "C";
-    })(M.E3 || (M.E3 = {}));
-    var E3 = M.E3;
+    })(E3 = M.E3 || (M.E3 = {}));
 })(M || (M = {}));
 (function (M) {
+    var E1;
     (function (E1) {
         E1[E1["C"] = 0] = "C";
-    })(M.E1 || (M.E1 = {}));
-    var E1 = M.E1;
+    })(E1 = M.E1 || (M.E1 = {}));
+    var E2;
     (function (E2) {
         E2[E2["A"] = 0] = "A";
-    })(M.E2 || (M.E2 = {}));
-    var E2 = M.E2;
+    })(E2 = M.E2 || (M.E2 = {}));
+    var E3;
     (function (E3) {
         E3[E3["B"] = 'foo'.length] = "B";
-    })(M.E3 || (M.E3 = {}));
-    var E3 = M.E3;
+    })(E3 = M.E3 || (M.E3 = {}));
 })(M || (M = {}));
 // Enum with no initializer in either declaration with constant members with the same root module
 var M1;
 (function (M1) {
+    var E1;
     (function (E1) {
         E1[E1["A"] = 0] = "A";
-    })(M1.E1 || (M1.E1 = {}));
-    var E1 = M1.E1;
+    })(E1 = M1.E1 || (M1.E1 = {}));
 })(M1 || (M1 = {}));
 (function (M1) {
+    var E1;
     (function (E1) {
         E1[E1["B"] = 0] = "B";
-    })(M1.E1 || (M1.E1 = {}));
-    var E1 = M1.E1;
+    })(E1 = M1.E1 || (M1.E1 = {}));
 })(M1 || (M1 = {}));
 (function (M1) {
+    var E1;
     (function (E1) {
         E1[E1["C"] = 0] = "C";
-    })(M1.E1 || (M1.E1 = {}));
-    var E1 = M1.E1;
+    })(E1 = M1.E1 || (M1.E1 = {}));
 })(M1 || (M1 = {}));
 // Enum with initializer in only one of three declarations with constant members with the same root module
 var M2;
 (function (M2) {
+    var E1;
     (function (E1) {
         E1[E1["A"] = 0] = "A";
-    })(M2.E1 || (M2.E1 = {}));
-    var E1 = M2.E1;
+    })(E1 = M2.E1 || (M2.E1 = {}));
 })(M2 || (M2 = {}));
 (function (M2) {
+    var E1;
     (function (E1) {
         E1[E1["B"] = 0] = "B";
-    })(M2.E1 || (M2.E1 = {}));
-    var E1 = M2.E1;
+    })(E1 = M2.E1 || (M2.E1 = {}));
 })(M2 || (M2 = {}));
 (function (M2) {
+    var E1;
     (function (E1) {
         E1[E1["C"] = 0] = "C";
-    })(M2.E1 || (M2.E1 = {}));
-    var E1 = M2.E1;
+    })(E1 = M2.E1 || (M2.E1 = {}));
 })(M2 || (M2 = {}));
diff --git a/tests/baselines/reference/es5ModuleInternalNamedImports.js b/tests/baselines/reference/es5ModuleInternalNamedImports.js
index 2fcbd5a53d885..cc596980889f2 100644
--- a/tests/baselines/reference/es5ModuleInternalNamedImports.js
+++ b/tests/baselines/reference/es5ModuleInternalNamedImports.js
@@ -59,9 +59,9 @@ define(["require", "exports"], function (require, exports) {
         function M_F() { }
         M.M_F = M_F;
         // enum
+        var M_E;
         (function (M_E) {
-        })(M.M_E || (M.M_E = {}));
-        var M_E = M.M_E;
+        })(M_E = M.M_E || (M.M_E = {}));
         // alias
         M.M_A = M_M;
     })(M = exports.M || (exports.M = {}));
diff --git a/tests/baselines/reference/es6ModuleConstEnumDeclaration2.js b/tests/baselines/reference/es6ModuleConstEnumDeclaration2.js
index 539ec121b6b57..3e4475f2ffa2c 100644
--- a/tests/baselines/reference/es6ModuleConstEnumDeclaration2.js
+++ b/tests/baselines/reference/es6ModuleConstEnumDeclaration2.js
@@ -63,12 +63,12 @@ var x = 0 /* a */;
 var y = 0 /* x */;
 export var m1;
 (function (m1) {
+    var e3;
     (function (e3) {
         e3[e3["a"] = 0] = "a";
         e3[e3["b"] = 1] = "b";
         e3[e3["c"] = 2] = "c";
-    })(m1.e3 || (m1.e3 = {}));
-    var e3 = m1.e3;
+    })(e3 = m1.e3 || (m1.e3 = {}));
     var e4;
     (function (e4) {
         e4[e4["x"] = 0] = "x";
@@ -82,12 +82,12 @@ export var m1;
 })(m1 || (m1 = {}));
 var m2;
 (function (m2) {
+    var e5;
     (function (e5) {
         e5[e5["a"] = 0] = "a";
         e5[e5["b"] = 1] = "b";
         e5[e5["c"] = 2] = "c";
-    })(m2.e5 || (m2.e5 = {}));
-    var e5 = m2.e5;
+    })(e5 = m2.e5 || (m2.e5 = {}));
     var e6;
     (function (e6) {
         e6[e6["x"] = 0] = "x";
diff --git a/tests/baselines/reference/es6ModuleEnumDeclaration.js b/tests/baselines/reference/es6ModuleEnumDeclaration.js
index 30c382a4508bc..91ba2efe8d386 100644
--- a/tests/baselines/reference/es6ModuleEnumDeclaration.js
+++ b/tests/baselines/reference/es6ModuleEnumDeclaration.js
@@ -62,12 +62,12 @@ var x = e1.a;
 var y = e2.x;
 export var m1;
 (function (m1) {
+    var e3;
     (function (e3) {
         e3[e3["a"] = 0] = "a";
         e3[e3["b"] = 1] = "b";
         e3[e3["c"] = 2] = "c";
-    })(m1.e3 || (m1.e3 = {}));
-    var e3 = m1.e3;
+    })(e3 = m1.e3 || (m1.e3 = {}));
     var e4;
     (function (e4) {
         e4[e4["x"] = 0] = "x";
@@ -81,12 +81,12 @@ export var m1;
 })(m1 || (m1 = {}));
 var m2;
 (function (m2) {
+    var e5;
     (function (e5) {
         e5[e5["a"] = 0] = "a";
         e5[e5["b"] = 1] = "b";
         e5[e5["c"] = 2] = "c";
-    })(m2.e5 || (m2.e5 = {}));
-    var e5 = m2.e5;
+    })(e5 = m2.e5 || (m2.e5 = {}));
     var e6;
     (function (e6) {
         e6[e6["x"] = 0] = "x";
diff --git a/tests/baselines/reference/es6ModuleInternalNamedImports.js b/tests/baselines/reference/es6ModuleInternalNamedImports.js
index 22d15b9fd61b3..fe2e0217795c2 100644
--- a/tests/baselines/reference/es6ModuleInternalNamedImports.js
+++ b/tests/baselines/reference/es6ModuleInternalNamedImports.js
@@ -50,9 +50,9 @@ export var M;
     function M_F() { }
     M.M_F = M_F;
     // enum
+    var M_E;
     (function (M_E) {
-    })(M.M_E || (M.M_E = {}));
-    var M_E = M.M_E;
+    })(M_E = M.M_E || (M.M_E = {}));
     // alias
     M.M_A = M_M;
 })(M || (M = {}));
diff --git a/tests/baselines/reference/es6ModuleInternalNamedImports2.js b/tests/baselines/reference/es6ModuleInternalNamedImports2.js
index 35eabc9a65e02..93d8f40c1d272 100644
--- a/tests/baselines/reference/es6ModuleInternalNamedImports2.js
+++ b/tests/baselines/reference/es6ModuleInternalNamedImports2.js
@@ -52,9 +52,9 @@ export var M;
     function M_F() { }
     M.M_F = M_F;
     // enum
+    var M_E;
     (function (M_E) {
-    })(M.M_E || (M.M_E = {}));
-    var M_E = M.M_E;
+    })(M_E = M.M_E || (M.M_E = {}));
     // alias
     M.M_A = M_M;
 })(M || (M = {}));
diff --git a/tests/baselines/reference/exportAssignmentAndDeclaration.js b/tests/baselines/reference/exportAssignmentAndDeclaration.js
index 9e87d733c6be0..df1f2ef0d0add 100644
--- a/tests/baselines/reference/exportAssignmentAndDeclaration.js
+++ b/tests/baselines/reference/exportAssignmentAndDeclaration.js
@@ -13,12 +13,12 @@ export = C1;
 //// [foo_0.js]
 define(["require", "exports"], function (require, exports) {
     "use strict";
+    var E1;
     (function (E1) {
         E1[E1["A"] = 0] = "A";
         E1[E1["B"] = 1] = "B";
         E1[E1["C"] = 2] = "C";
-    })(exports.E1 || (exports.E1 = {}));
-    var E1 = exports.E1;
+    })(E1 = exports.E1 || (exports.E1 = {}));
     var C1 = (function () {
         function C1() {
         }
diff --git a/tests/baselines/reference/exportCodeGen.js b/tests/baselines/reference/exportCodeGen.js
index 41564c35d1a68..d72c633731df5 100644
--- a/tests/baselines/reference/exportCodeGen.js
+++ b/tests/baselines/reference/exportCodeGen.js
@@ -90,10 +90,10 @@ var D;
 // validate all exportable statements
 var E;
 (function (E) {
+    var Color;
     (function (Color) {
         Color[Color["Red"] = 0] = "Red";
-    })(E.Color || (E.Color = {}));
-    var Color = E.Color;
+    })(Color = E.Color || (E.Color = {}));
     function fn() { }
     E.fn = fn;
     var C = (function () {
diff --git a/tests/baselines/reference/exportsAndImports3-amd.js b/tests/baselines/reference/exportsAndImports3-amd.js
index 0e315f1f18b23..cbf30735182db 100644
--- a/tests/baselines/reference/exportsAndImports3-amd.js
+++ b/tests/baselines/reference/exportsAndImports3-amd.js
@@ -49,12 +49,12 @@ define(["require", "exports"], function (require, exports) {
     }());
     exports.C = C;
     exports.C1 = C;
+    var E;
     (function (E) {
         E[E["A"] = 0] = "A";
         E[E["B"] = 1] = "B";
         E[E["C"] = 2] = "C";
-    })(exports.E || (exports.E = {}));
-    var E = exports.E;
+    })(E = exports.E || (exports.E = {}));
     exports.E1 = E;
     var M;
     (function (M) {
diff --git a/tests/baselines/reference/exportsAndImports3-es6.js b/tests/baselines/reference/exportsAndImports3-es6.js
index ea16836b1f202..85daa3f0f5ccd 100644
--- a/tests/baselines/reference/exportsAndImports3-es6.js
+++ b/tests/baselines/reference/exportsAndImports3-es6.js
@@ -45,12 +45,12 @@ class C {
 }
 exports.C = C;
 exports.C1 = C;
+var E;
 (function (E) {
     E[E["A"] = 0] = "A";
     E[E["B"] = 1] = "B";
     E[E["C"] = 2] = "C";
-})(exports.E || (exports.E = {}));
-var E = exports.E;
+})(E = exports.E || (exports.E = {}));
 exports.E1 = E;
 var M;
 (function (M) {
diff --git a/tests/baselines/reference/exportsAndImports3.js b/tests/baselines/reference/exportsAndImports3.js
index 16115a192da28..dbcd94862153c 100644
--- a/tests/baselines/reference/exportsAndImports3.js
+++ b/tests/baselines/reference/exportsAndImports3.js
@@ -48,12 +48,12 @@ var C = (function () {
 }());
 exports.C = C;
 exports.C1 = C;
+var E;
 (function (E) {
     E[E["A"] = 0] = "A";
     E[E["B"] = 1] = "B";
     E[E["C"] = 2] = "C";
-})(exports.E || (exports.E = {}));
-var E = exports.E;
+})(E = exports.E || (exports.E = {}));
 exports.E1 = E;
 var M;
 (function (M) {
diff --git a/tests/baselines/reference/genericRecursiveImplicitConstructorErrors2.js b/tests/baselines/reference/genericRecursiveImplicitConstructorErrors2.js
index 6d65ee5531b6d..401a2e94b6819 100644
--- a/tests/baselines/reference/genericRecursiveImplicitConstructorErrors2.js
+++ b/tests/baselines/reference/genericRecursiveImplicitConstructorErrors2.js
@@ -37,11 +37,11 @@ var TypeScript2;
     ;
     ;
     ;
+    var PullSymbolVisibility;
     (function (PullSymbolVisibility) {
         PullSymbolVisibility[PullSymbolVisibility["Private"] = 0] = "Private";
         PullSymbolVisibility[PullSymbolVisibility["Public"] = 1] = "Public";
-    })(TypeScript2.PullSymbolVisibility || (TypeScript2.PullSymbolVisibility = {}));
-    var PullSymbolVisibility = TypeScript2.PullSymbolVisibility;
+    })(PullSymbolVisibility = TypeScript2.PullSymbolVisibility || (TypeScript2.PullSymbolVisibility = {}));
     var PullSymbol = (function () {
         function PullSymbol(name, declKind) {
         }
diff --git a/tests/baselines/reference/instantiatedModule.js b/tests/baselines/reference/instantiatedModule.js
index d8ef427619ab1..8e7027d5fd7a9 100644
--- a/tests/baselines/reference/instantiatedModule.js
+++ b/tests/baselines/reference/instantiatedModule.js
@@ -101,11 +101,11 @@ var p2 = new m2.Point();
 var p2 = new M2.Point();
 var M3;
 (function (M3) {
+    var Color;
     (function (Color) {
         Color[Color["Blue"] = 0] = "Blue";
         Color[Color["Red"] = 1] = "Red";
-    })(M3.Color || (M3.Color = {}));
-    var Color = M3.Color;
+    })(Color = M3.Color || (M3.Color = {}));
 })(M3 || (M3 = {}));
 var m3;
 var m3 = M3;
diff --git a/tests/baselines/reference/interfaceAssignmentCompat.js b/tests/baselines/reference/interfaceAssignmentCompat.js
index edaebbd38a25b..98586da24e5a9 100644
--- a/tests/baselines/reference/interfaceAssignmentCompat.js
+++ b/tests/baselines/reference/interfaceAssignmentCompat.js
@@ -55,12 +55,12 @@ M.test();
 //// [interfaceAssignmentCompat.js]
 var M;
 (function (M) {
+    var Color;
     (function (Color) {
         Color[Color["Green"] = 0] = "Green";
         Color[Color["Blue"] = 1] = "Blue";
         Color[Color["Brown"] = 2] = "Brown";
-    })(M.Color || (M.Color = {}));
-    var Color = M.Color;
+    })(Color = M.Color || (M.Color = {}));
     function CompareEyes(a, b) {
         return a.color - b.color;
     }
diff --git a/tests/baselines/reference/internalAliasEnum.js b/tests/baselines/reference/internalAliasEnum.js
index 6400cf26ddcff..40fac82eb4d46 100644
--- a/tests/baselines/reference/internalAliasEnum.js
+++ b/tests/baselines/reference/internalAliasEnum.js
@@ -16,12 +16,12 @@ module c {
 //// [internalAliasEnum.js]
 var a;
 (function (a) {
+    var weekend;
     (function (weekend) {
         weekend[weekend["Friday"] = 0] = "Friday";
         weekend[weekend["Saturday"] = 1] = "Saturday";
         weekend[weekend["Sunday"] = 2] = "Sunday";
-    })(a.weekend || (a.weekend = {}));
-    var weekend = a.weekend;
+    })(weekend = a.weekend || (a.weekend = {}));
 })(a || (a = {}));
 var c;
 (function (c) {
diff --git a/tests/baselines/reference/internalAliasEnumInsideLocalModuleWithExport.js b/tests/baselines/reference/internalAliasEnumInsideLocalModuleWithExport.js
index dd30dc814aed3..c7b8bf2cacc32 100644
--- a/tests/baselines/reference/internalAliasEnumInsideLocalModuleWithExport.js
+++ b/tests/baselines/reference/internalAliasEnumInsideLocalModuleWithExport.js
@@ -17,12 +17,12 @@ export module c {
 "use strict";
 var a;
 (function (a) {
+    var weekend;
     (function (weekend) {
         weekend[weekend["Friday"] = 0] = "Friday";
         weekend[weekend["Saturday"] = 1] = "Saturday";
         weekend[weekend["Sunday"] = 2] = "Sunday";
-    })(a.weekend || (a.weekend = {}));
-    var weekend = a.weekend;
+    })(weekend = a.weekend || (a.weekend = {}));
 })(a = exports.a || (exports.a = {}));
 var c;
 (function (c) {
diff --git a/tests/baselines/reference/internalAliasEnumInsideLocalModuleWithoutExport.js b/tests/baselines/reference/internalAliasEnumInsideLocalModuleWithoutExport.js
index 7f00d69a8d6f9..267fffc7b7098 100644
--- a/tests/baselines/reference/internalAliasEnumInsideLocalModuleWithoutExport.js
+++ b/tests/baselines/reference/internalAliasEnumInsideLocalModuleWithoutExport.js
@@ -17,12 +17,12 @@ export module c {
 "use strict";
 var a;
 (function (a) {
+    var weekend;
     (function (weekend) {
         weekend[weekend["Friday"] = 0] = "Friday";
         weekend[weekend["Saturday"] = 1] = "Saturday";
         weekend[weekend["Sunday"] = 2] = "Sunday";
-    })(a.weekend || (a.weekend = {}));
-    var weekend = a.weekend;
+    })(weekend = a.weekend || (a.weekend = {}));
 })(a = exports.a || (exports.a = {}));
 var c;
 (function (c) {
diff --git a/tests/baselines/reference/internalAliasEnumInsideLocalModuleWithoutExportAccessError.js b/tests/baselines/reference/internalAliasEnumInsideLocalModuleWithoutExportAccessError.js
index 8612e74f82955..a44298b6864ba 100644
--- a/tests/baselines/reference/internalAliasEnumInsideLocalModuleWithoutExportAccessError.js
+++ b/tests/baselines/reference/internalAliasEnumInsideLocalModuleWithoutExportAccessError.js
@@ -18,12 +18,12 @@ var happyFriday = c.b.Friday;
 "use strict";
 var a;
 (function (a) {
+    var weekend;
     (function (weekend) {
         weekend[weekend["Friday"] = 0] = "Friday";
         weekend[weekend["Saturday"] = 1] = "Saturday";
         weekend[weekend["Sunday"] = 2] = "Sunday";
-    })(a.weekend || (a.weekend = {}));
-    var weekend = a.weekend;
+    })(weekend = a.weekend || (a.weekend = {}));
 })(a = exports.a || (exports.a = {}));
 var c;
 (function (c) {
diff --git a/tests/baselines/reference/internalAliasEnumInsideTopLevelModuleWithExport.js b/tests/baselines/reference/internalAliasEnumInsideTopLevelModuleWithExport.js
index c7396fded2ac2..8e11f60dcc71c 100644
--- a/tests/baselines/reference/internalAliasEnumInsideTopLevelModuleWithExport.js
+++ b/tests/baselines/reference/internalAliasEnumInsideTopLevelModuleWithExport.js
@@ -16,12 +16,12 @@ define(["require", "exports"], function (require, exports) {
     "use strict";
     var a;
     (function (a) {
+        var weekend;
         (function (weekend) {
             weekend[weekend["Friday"] = 0] = "Friday";
             weekend[weekend["Saturday"] = 1] = "Saturday";
             weekend[weekend["Sunday"] = 2] = "Sunday";
-        })(a.weekend || (a.weekend = {}));
-        var weekend = a.weekend;
+        })(weekend = a.weekend || (a.weekend = {}));
     })(a = exports.a || (exports.a = {}));
     exports.b = a.weekend;
     exports.bVal = exports.b.Sunday;
diff --git a/tests/baselines/reference/internalAliasEnumInsideTopLevelModuleWithoutExport.js b/tests/baselines/reference/internalAliasEnumInsideTopLevelModuleWithoutExport.js
index 1cf1b0b8b1633..8ec0dcea81575 100644
--- a/tests/baselines/reference/internalAliasEnumInsideTopLevelModuleWithoutExport.js
+++ b/tests/baselines/reference/internalAliasEnumInsideTopLevelModuleWithoutExport.js
@@ -16,12 +16,12 @@ define(["require", "exports"], function (require, exports) {
     "use strict";
     var a;
     (function (a) {
+        var weekend;
         (function (weekend) {
             weekend[weekend["Friday"] = 0] = "Friday";
             weekend[weekend["Saturday"] = 1] = "Saturday";
             weekend[weekend["Sunday"] = 2] = "Sunday";
-        })(a.weekend || (a.weekend = {}));
-        var weekend = a.weekend;
+        })(weekend = a.weekend || (a.weekend = {}));
     })(a = exports.a || (exports.a = {}));
     var b = a.weekend;
     exports.bVal = b.Sunday;
diff --git a/tests/baselines/reference/localImportNameVsGlobalName.js b/tests/baselines/reference/localImportNameVsGlobalName.js
index 45ecdc4745e36..916bdcc296050 100644
--- a/tests/baselines/reference/localImportNameVsGlobalName.js
+++ b/tests/baselines/reference/localImportNameVsGlobalName.js
@@ -16,13 +16,13 @@ module App {
 //// [localImportNameVsGlobalName.js]
 var Keyboard;
 (function (Keyboard) {
+    var Key;
     (function (Key) {
         Key[Key["UP"] = 0] = "UP";
         Key[Key["DOWN"] = 1] = "DOWN";
         Key[Key["LEFT"] = 2] = "LEFT";
         Key[Key["RIGHT"] = 3] = "RIGHT";
-    })(Keyboard.Key || (Keyboard.Key = {}));
-    var Key = Keyboard.Key;
+    })(Key = Keyboard.Key || (Keyboard.Key = {}));
 })(Keyboard || (Keyboard = {}));
 var App;
 (function (App) {
diff --git a/tests/baselines/reference/mergeWithImportedType.js b/tests/baselines/reference/mergeWithImportedType.js
index 89fc353d395da..e8dc5a3c2f37b 100644
--- a/tests/baselines/reference/mergeWithImportedType.js
+++ b/tests/baselines/reference/mergeWithImportedType.js
@@ -10,9 +10,9 @@ export type E = E;
 
 //// [f1.js]
 "use strict";
+var E;
 (function (E) {
     E[E["X"] = 0] = "X";
-})(exports.E || (exports.E = {}));
-var E = exports.E;
+})(E = exports.E || (exports.E = {}));
 //// [f2.js]
 "use strict";
diff --git a/tests/baselines/reference/mergedDeclarations3.js b/tests/baselines/reference/mergedDeclarations3.js
index ddf94b46e81c9..d3b4e8fc9d579 100644
--- a/tests/baselines/reference/mergedDeclarations3.js
+++ b/tests/baselines/reference/mergedDeclarations3.js
@@ -42,11 +42,11 @@ M.foo.z // error
 //// [mergedDeclarations3.js]
 var M;
 (function (M) {
+    var Color;
     (function (Color) {
         Color[Color["Red"] = 0] = "Red";
         Color[Color["Green"] = 1] = "Green";
-    })(M.Color || (M.Color = {}));
-    var Color = M.Color;
+    })(Color = M.Color || (M.Color = {}));
 })(M || (M = {}));
 (function (M) {
     var Color;
diff --git a/tests/baselines/reference/mergedModuleDeclarationCodeGen5.js b/tests/baselines/reference/mergedModuleDeclarationCodeGen5.js
index 11a4773d63a50..8891dbf61e22c 100644
--- a/tests/baselines/reference/mergedModuleDeclarationCodeGen5.js
+++ b/tests/baselines/reference/mergedModuleDeclarationCodeGen5.js
@@ -45,9 +45,9 @@ var M;
                 return fudge;
             }());
             plop_1.fudge = fudge;
+            var plop;
             (function (plop) {
-            })(plop_1.plop || (plop_1.plop = {}));
-            var plop = plop_1.plop;
+            })(plop = plop_1.plop || (plop_1.plop = {}));
             // Emit these references as follows
             var v1 = gunk; // gunk
             var v2 = buz; // buz
diff --git a/tests/baselines/reference/moduleCodeGenTest5.js b/tests/baselines/reference/moduleCodeGenTest5.js
index fa09b432ab7ac..6a7113c03688e 100644
--- a/tests/baselines/reference/moduleCodeGenTest5.js
+++ b/tests/baselines/reference/moduleCodeGenTest5.js
@@ -43,10 +43,10 @@ var C2 = (function () {
     C2.prototype.p2 = function () { };
     return C2;
 }());
+var E1;
 (function (E1) {
     E1[E1["A"] = 0] = "A";
-})(exports.E1 || (exports.E1 = {}));
-var E1 = exports.E1;
+})(E1 = exports.E1 || (exports.E1 = {}));
 var u = E1.A;
 var E2;
 (function (E2) {
diff --git a/tests/baselines/reference/moduleDuplicateIdentifiers.js b/tests/baselines/reference/moduleDuplicateIdentifiers.js
index 097192ac73c79..64b82f82500ee 100644
--- a/tests/baselines/reference/moduleDuplicateIdentifiers.js
+++ b/tests/baselines/reference/moduleDuplicateIdentifiers.js
@@ -67,12 +67,12 @@ var Kettle = (function () {
 exports.Kettle = Kettle;
 exports.Pot = 2;
 exports.Pot = 42; // Shouldn't error
+var Utensils;
 (function (Utensils) {
     Utensils[Utensils["Spoon"] = 0] = "Spoon";
     Utensils[Utensils["Fork"] = 1] = "Fork";
     Utensils[Utensils["Knife"] = 2] = "Knife";
-})(exports.Utensils || (exports.Utensils = {}));
-var Utensils = exports.Utensils;
+})(Utensils = exports.Utensils || (exports.Utensils = {}));
 (function (Utensils) {
     Utensils[Utensils["Spork"] = 3] = "Spork";
-})(exports.Utensils || (exports.Utensils = {}));
+})(Utensils = exports.Utensils || (exports.Utensils = {}));
diff --git a/tests/baselines/reference/moduleSameValueDuplicateExportedBindings2.js b/tests/baselines/reference/moduleSameValueDuplicateExportedBindings2.js
index 99a09af149ada..208e90c69d8c8 100644
--- a/tests/baselines/reference/moduleSameValueDuplicateExportedBindings2.js
+++ b/tests/baselines/reference/moduleSameValueDuplicateExportedBindings2.js
@@ -15,11 +15,11 @@ export enum Animals {
 
 //// [c.js]
 "use strict";
+var Animals;
 (function (Animals) {
     Animals[Animals["Cat"] = 0] = "Cat";
     Animals[Animals["Dog"] = 1] = "Dog";
-})(exports.Animals || (exports.Animals = {}));
-var Animals = exports.Animals;
+})(Animals = exports.Animals || (exports.Animals = {}));
 ;
 //// [b.js]
 "use strict";
diff --git a/tests/baselines/reference/moduleVisibilityTest1.js b/tests/baselines/reference/moduleVisibilityTest1.js
index 52afcf169d91b..537ec23b3937c 100644
--- a/tests/baselines/reference/moduleVisibilityTest1.js
+++ b/tests/baselines/reference/moduleVisibilityTest1.js
@@ -86,12 +86,12 @@ var M;
         function someExportedInnerFunc() { return -2; }
         InnerMod.someExportedInnerFunc = someExportedInnerFunc;
     })(InnerMod = M.InnerMod || (M.InnerMod = {}));
+    var E;
     (function (E) {
         E[E["A"] = 0] = "A";
         E[E["B"] = 1] = "B";
         E[E["C"] = 2] = "C";
-    })(M.E || (M.E = {}));
-    var E = M.E;
+    })(E = M.E || (M.E = {}));
     M.x = 5;
     var y = M.x + M.x;
     var B = (function () {
diff --git a/tests/baselines/reference/moduleWithStatementsOfEveryKind.js b/tests/baselines/reference/moduleWithStatementsOfEveryKind.js
index 1558ef742ab14..4243c9849cf7f 100644
--- a/tests/baselines/reference/moduleWithStatementsOfEveryKind.js
+++ b/tests/baselines/reference/moduleWithStatementsOfEveryKind.js
@@ -151,11 +151,11 @@ var Y;
             return A;
         }());
     })(Module = Y.Module || (Y.Module = {}));
+    var Color;
     (function (Color) {
         Color[Color["Blue"] = 0] = "Blue";
         Color[Color["Red"] = 1] = "Red";
-    })(Y.Color || (Y.Color = {}));
-    var Color = Y.Color;
+    })(Color = Y.Color || (Y.Color = {}));
     Y.x = 12;
     function F(s) {
         return 2;
diff --git a/tests/baselines/reference/nameCollision.js b/tests/baselines/reference/nameCollision.js
index e51bd5e7c6904..bb4f4a092f9d7 100644
--- a/tests/baselines/reference/nameCollision.js
+++ b/tests/baselines/reference/nameCollision.js
@@ -85,11 +85,11 @@ var Y;
 (function (Y_2) {
     var Y;
     (function (Y_3) {
+        var Y;
         (function (Y) {
             Y[Y["Red"] = 0] = "Red";
             Y[Y["Blue"] = 1] = "Blue";
-        })(Y_3.Y || (Y_3.Y = {}));
-        var Y = Y_3.Y;
+        })(Y = Y_3.Y || (Y_3.Y = {}));
     })(Y = Y_2.Y || (Y_2.Y = {}));
 })(Y || (Y = {}));
 // no collision, since interface doesn't
diff --git a/tests/baselines/reference/parserEnum1.js b/tests/baselines/reference/parserEnum1.js
index e54fff50c7392..d2c29d847cd79 100644
--- a/tests/baselines/reference/parserEnum1.js
+++ b/tests/baselines/reference/parserEnum1.js
@@ -10,10 +10,10 @@
 
 //// [parserEnum1.js]
 "use strict";
+var SignatureFlags;
 (function (SignatureFlags) {
     SignatureFlags[SignatureFlags["None"] = 0] = "None";
     SignatureFlags[SignatureFlags["IsIndexer"] = 1] = "IsIndexer";
     SignatureFlags[SignatureFlags["IsStringIndexer"] = 2] = "IsStringIndexer";
     SignatureFlags[SignatureFlags["IsNumberIndexer"] = 4] = "IsNumberIndexer";
-})(exports.SignatureFlags || (exports.SignatureFlags = {}));
-var SignatureFlags = exports.SignatureFlags;
+})(SignatureFlags = exports.SignatureFlags || (exports.SignatureFlags = {}));
diff --git a/tests/baselines/reference/parserEnum2.js b/tests/baselines/reference/parserEnum2.js
index 8e7da5c73cd8d..f5888addf7539 100644
--- a/tests/baselines/reference/parserEnum2.js
+++ b/tests/baselines/reference/parserEnum2.js
@@ -10,10 +10,10 @@
 
 //// [parserEnum2.js]
 "use strict";
+var SignatureFlags;
 (function (SignatureFlags) {
     SignatureFlags[SignatureFlags["None"] = 0] = "None";
     SignatureFlags[SignatureFlags["IsIndexer"] = 1] = "IsIndexer";
     SignatureFlags[SignatureFlags["IsStringIndexer"] = 2] = "IsStringIndexer";
     SignatureFlags[SignatureFlags["IsNumberIndexer"] = 4] = "IsNumberIndexer";
-})(exports.SignatureFlags || (exports.SignatureFlags = {}));
-var SignatureFlags = exports.SignatureFlags;
+})(SignatureFlags = exports.SignatureFlags || (exports.SignatureFlags = {}));
diff --git a/tests/baselines/reference/parserEnum3.js b/tests/baselines/reference/parserEnum3.js
index 1d0c445d3a0d0..602171e8d9449 100644
--- a/tests/baselines/reference/parserEnum3.js
+++ b/tests/baselines/reference/parserEnum3.js
@@ -6,6 +6,6 @@
 
 //// [parserEnum3.js]
 "use strict";
+var SignatureFlags;
 (function (SignatureFlags) {
-})(exports.SignatureFlags || (exports.SignatureFlags = {}));
-var SignatureFlags = exports.SignatureFlags;
+})(SignatureFlags = exports.SignatureFlags || (exports.SignatureFlags = {}));
diff --git a/tests/baselines/reference/parserEnum4.js b/tests/baselines/reference/parserEnum4.js
index 1a207960714a3..6af07b0a1c79a 100644
--- a/tests/baselines/reference/parserEnum4.js
+++ b/tests/baselines/reference/parserEnum4.js
@@ -7,6 +7,6 @@
 
 //// [parserEnum4.js]
 "use strict";
+var SignatureFlags;
 (function (SignatureFlags) {
-})(exports.SignatureFlags || (exports.SignatureFlags = {}));
-var SignatureFlags = exports.SignatureFlags;
+})(SignatureFlags = exports.SignatureFlags || (exports.SignatureFlags = {}));
diff --git a/tests/baselines/reference/parserRealSource10.js b/tests/baselines/reference/parserRealSource10.js
index 253f856a9900f..11cfbdfa1f21e 100644
--- a/tests/baselines/reference/parserRealSource10.js
+++ b/tests/baselines/reference/parserRealSource10.js
@@ -466,6 +466,7 @@ var __extends = (this && this.__extends) || function (d, b) {
 ///<reference path='typescript.ts' />
 var TypeScript;
 (function (TypeScript) {
+    var TokenID;
     (function (TokenID) {
         // Keywords
         TokenID[TokenID["Any"] = 0] = "Any";
@@ -584,8 +585,7 @@ var TypeScript;
         TokenID[TokenID["Lim"] = 112] = "Lim";
         TokenID[TokenID["LimFixed"] = 105] = "LimFixed";
         TokenID[TokenID["LimKeyword"] = 53] = "LimKeyword";
-    })(TypeScript.TokenID || (TypeScript.TokenID = {}));
-    var TokenID = TypeScript.TokenID;
+    })(TokenID = TypeScript.TokenID || (TypeScript.TokenID = {}));
     TypeScript.tokenTable = new TokenInfo[];
     TypeScript.nodeTypeTable = new string[];
     TypeScript.nodeTypeToTokTable = new number[];
@@ -602,6 +602,7 @@ var TypeScript;
     TypeScript.noRegexTable[TokenID.CloseBrace] = true;
     TypeScript.noRegexTable[TokenID.True] = true;
     TypeScript.noRegexTable[TokenID.False] = true;
+    var OperatorPrecedence;
     (function (OperatorPrecedence) {
         OperatorPrecedence[OperatorPrecedence["None"] = 0] = "None";
         OperatorPrecedence[OperatorPrecedence["Comma"] = 1] = "Comma";
@@ -619,8 +620,8 @@ var TypeScript;
         OperatorPrecedence[OperatorPrecedence["Multiplicative"] = 13] = "Multiplicative";
         OperatorPrecedence[OperatorPrecedence["Unary"] = 14] = "Unary";
         OperatorPrecedence[OperatorPrecedence["Lim"] = 15] = "Lim";
-    })(TypeScript.OperatorPrecedence || (TypeScript.OperatorPrecedence = {}));
-    var OperatorPrecedence = TypeScript.OperatorPrecedence;
+    })(OperatorPrecedence = TypeScript.OperatorPrecedence || (TypeScript.OperatorPrecedence = {}));
+    var Reservation;
     (function (Reservation) {
         Reservation[Reservation["None"] = 0] = "None";
         Reservation[Reservation["Javascript"] = 1] = "Javascript";
@@ -630,8 +631,7 @@ var TypeScript;
         Reservation[Reservation["TypeScriptAndJS"] = 5] = "TypeScriptAndJS";
         Reservation[Reservation["TypeScriptAndJSFuture"] = 6] = "TypeScriptAndJSFuture";
         Reservation[Reservation["TypeScriptAndJSFutureStrict"] = 12] = "TypeScriptAndJSFutureStrict";
-    })(TypeScript.Reservation || (TypeScript.Reservation = {}));
-    var Reservation = TypeScript.Reservation;
+    })(Reservation = TypeScript.Reservation || (TypeScript.Reservation = {}));
     var TokenInfo = (function () {
         function TokenInfo(tokenId, reservation, binopPrecedence, binopNodeType, unopPrecedence, unopNodeType, text, ers) {
             this.tokenId = tokenId;
@@ -773,6 +773,7 @@ var TypeScript;
         return TypeScript.tokenTable[tokenId];
     }
     TypeScript.lookupToken = lookupToken;
+    var TokenClass;
     (function (TokenClass) {
         TokenClass[TokenClass["Punctuation"] = 0] = "Punctuation";
         TokenClass[TokenClass["Keyword"] = 1] = "Keyword";
@@ -781,8 +782,7 @@ var TypeScript;
         TokenClass[TokenClass["Whitespace"] = 4] = "Whitespace";
         TokenClass[TokenClass["Identifier"] = 5] = "Identifier";
         TokenClass[TokenClass["Literal"] = 6] = "Literal";
-    })(TypeScript.TokenClass || (TypeScript.TokenClass = {}));
-    var TokenClass = TypeScript.TokenClass;
+    })(TokenClass = TypeScript.TokenClass || (TypeScript.TokenClass = {}));
     var SavedToken = (function () {
         function SavedToken(tok, minChar, limChar) {
             this.tok = tok;
diff --git a/tests/baselines/reference/parserRealSource14.js b/tests/baselines/reference/parserRealSource14.js
index c31a9dd6c7244..907efc6f26a1e 100644
--- a/tests/baselines/reference/parserRealSource14.js
+++ b/tests/baselines/reference/parserRealSource14.js
@@ -957,6 +957,7 @@ var TypeScript;
         return AstPathContext;
     }());
     TypeScript.AstPathContext = AstPathContext;
+    var GetAstPathOptions;
     (function (GetAstPathOptions) {
         GetAstPathOptions[GetAstPathOptions["Default"] = 0] = "Default";
         GetAstPathOptions[GetAstPathOptions["EdgeInclusive"] = 1] = "EdgeInclusive";
@@ -968,8 +969,7 @@ var TypeScript;
         // we don't find the "precomment" attached to the errorneous empty stmt.
         //TODO: It would be nice to be able to get rid of this.
         GetAstPathOptions[GetAstPathOptions["DontPruneSearchBasedOnPosition"] = 2] = "DontPruneSearchBasedOnPosition";
-    })(TypeScript.GetAstPathOptions || (TypeScript.GetAstPathOptions = {}));
-    var GetAstPathOptions = TypeScript.GetAstPathOptions;
+    })(GetAstPathOptions = TypeScript.GetAstPathOptions || (TypeScript.GetAstPathOptions = {}));
     ///
     /// Return the stack of AST nodes containing "position"
     ///
diff --git a/tests/baselines/reference/parserRealSource2.js b/tests/baselines/reference/parserRealSource2.js
index c41f88bc9c20c..2028cbd4efe35 100644
--- a/tests/baselines/reference/parserRealSource2.js
+++ b/tests/baselines/reference/parserRealSource2.js
@@ -281,6 +281,7 @@ var TypeScript;
         return (val & flag) != 0;
     }
     TypeScript.hasFlag = hasFlag;
+    var ErrorRecoverySet;
     (function (ErrorRecoverySet) {
         ErrorRecoverySet[ErrorRecoverySet["None"] = 0] = "None";
         ErrorRecoverySet[ErrorRecoverySet["Comma"] = 1] = "Comma";
@@ -320,8 +321,8 @@ var TypeScript;
         ErrorRecoverySet[ErrorRecoverySet["ExprStart"] = 520158210] = "ExprStart";
         ErrorRecoverySet[ErrorRecoverySet["StmtStart"] = 1608580098] = "StmtStart";
         ErrorRecoverySet[ErrorRecoverySet["Postfix"] = 49280] = "Postfix";
-    })(TypeScript.ErrorRecoverySet || (TypeScript.ErrorRecoverySet = {}));
-    var ErrorRecoverySet = TypeScript.ErrorRecoverySet;
+    })(ErrorRecoverySet = TypeScript.ErrorRecoverySet || (TypeScript.ErrorRecoverySet = {}));
+    var AllowedElements;
     (function (AllowedElements) {
         AllowedElements[AllowedElements["None"] = 0] = "None";
         AllowedElements[AllowedElements["ModuleDeclarations"] = 4] = "ModuleDeclarations";
@@ -331,8 +332,8 @@ var TypeScript;
         AllowedElements[AllowedElements["Properties"] = 2048] = "Properties";
         AllowedElements[AllowedElements["Global"] = 1052] = "Global";
         AllowedElements[AllowedElements["QuickParse"] = 3100] = "QuickParse";
-    })(TypeScript.AllowedElements || (TypeScript.AllowedElements = {}));
-    var AllowedElements = TypeScript.AllowedElements;
+    })(AllowedElements = TypeScript.AllowedElements || (TypeScript.AllowedElements = {}));
+    var Modifiers;
     (function (Modifiers) {
         Modifiers[Modifiers["None"] = 0] = "None";
         Modifiers[Modifiers["Private"] = 1] = "Private";
@@ -343,8 +344,8 @@ var TypeScript;
         Modifiers[Modifiers["Getter"] = 32] = "Getter";
         Modifiers[Modifiers["Setter"] = 64] = "Setter";
         Modifiers[Modifiers["Static"] = 128] = "Static";
-    })(TypeScript.Modifiers || (TypeScript.Modifiers = {}));
-    var Modifiers = TypeScript.Modifiers;
+    })(Modifiers = TypeScript.Modifiers || (TypeScript.Modifiers = {}));
+    var ASTFlags;
     (function (ASTFlags) {
         ASTFlags[ASTFlags["None"] = 0] = "None";
         ASTFlags[ASTFlags["ExplicitSemicolon"] = 1] = "ExplicitSemicolon";
@@ -362,8 +363,8 @@ var TypeScript;
         //         The flag is used to communicate this piece of information to the calling parseTerm, which intern will remove it.
         //         Once we have a better way to associate information with nodes, this flag should not be used.
         ASTFlags[ASTFlags["SkipNextRParen"] = 2048] = "SkipNextRParen";
-    })(TypeScript.ASTFlags || (TypeScript.ASTFlags = {}));
-    var ASTFlags = TypeScript.ASTFlags;
+    })(ASTFlags = TypeScript.ASTFlags || (TypeScript.ASTFlags = {}));
+    var DeclFlags;
     (function (DeclFlags) {
         DeclFlags[DeclFlags["None"] = 0] = "None";
         DeclFlags[DeclFlags["Exported"] = 1] = "Exported";
@@ -374,8 +375,8 @@ var TypeScript;
         DeclFlags[DeclFlags["LocalStatic"] = 32] = "LocalStatic";
         DeclFlags[DeclFlags["GetAccessor"] = 64] = "GetAccessor";
         DeclFlags[DeclFlags["SetAccessor"] = 128] = "SetAccessor";
-    })(TypeScript.DeclFlags || (TypeScript.DeclFlags = {}));
-    var DeclFlags = TypeScript.DeclFlags;
+    })(DeclFlags = TypeScript.DeclFlags || (TypeScript.DeclFlags = {}));
+    var ModuleFlags;
     (function (ModuleFlags) {
         ModuleFlags[ModuleFlags["None"] = 0] = "None";
         ModuleFlags[ModuleFlags["Exported"] = 1] = "Exported";
@@ -391,8 +392,8 @@ var TypeScript;
         ModuleFlags[ModuleFlags["IsWholeFile"] = 1024] = "IsWholeFile";
         ModuleFlags[ModuleFlags["IsDynamic"] = 2048] = "IsDynamic";
         ModuleFlags[ModuleFlags["MustCaptureThis"] = 4096] = "MustCaptureThis";
-    })(TypeScript.ModuleFlags || (TypeScript.ModuleFlags = {}));
-    var ModuleFlags = TypeScript.ModuleFlags;
+    })(ModuleFlags = TypeScript.ModuleFlags || (TypeScript.ModuleFlags = {}));
+    var SymbolFlags;
     (function (SymbolFlags) {
         SymbolFlags[SymbolFlags["None"] = 0] = "None";
         SymbolFlags[SymbolFlags["Exported"] = 1] = "Exported";
@@ -415,8 +416,8 @@ var TypeScript;
         SymbolFlags[SymbolFlags["RecursivelyReferenced"] = 131072] = "RecursivelyReferenced";
         SymbolFlags[SymbolFlags["Bound"] = 262144] = "Bound";
         SymbolFlags[SymbolFlags["CompilerGenerated"] = 524288] = "CompilerGenerated";
-    })(TypeScript.SymbolFlags || (TypeScript.SymbolFlags = {}));
-    var SymbolFlags = TypeScript.SymbolFlags;
+    })(SymbolFlags = TypeScript.SymbolFlags || (TypeScript.SymbolFlags = {}));
+    var VarFlags;
     (function (VarFlags) {
         VarFlags[VarFlags["None"] = 0] = "None";
         VarFlags[VarFlags["Exported"] = 1] = "Exported";
@@ -437,8 +438,8 @@ var TypeScript;
         VarFlags[VarFlags["ClassSuperMustBeFirstCallInConstructor"] = 32768] = "ClassSuperMustBeFirstCallInConstructor";
         VarFlags[VarFlags["Constant"] = 65536] = "Constant";
         VarFlags[VarFlags["MustCaptureThis"] = 131072] = "MustCaptureThis";
-    })(TypeScript.VarFlags || (TypeScript.VarFlags = {}));
-    var VarFlags = TypeScript.VarFlags;
+    })(VarFlags = TypeScript.VarFlags || (TypeScript.VarFlags = {}));
+    var FncFlags;
     (function (FncFlags) {
         FncFlags[FncFlags["None"] = 0] = "None";
         FncFlags[FncFlags["Exported"] = 1] = "Exported";
@@ -461,19 +462,19 @@ var TypeScript;
         FncFlags[FncFlags["IsFunctionExpression"] = 131072] = "IsFunctionExpression";
         FncFlags[FncFlags["ClassMethod"] = 262144] = "ClassMethod";
         FncFlags[FncFlags["ClassPropertyMethodExported"] = 524288] = "ClassPropertyMethodExported";
-    })(TypeScript.FncFlags || (TypeScript.FncFlags = {}));
-    var FncFlags = TypeScript.FncFlags;
+    })(FncFlags = TypeScript.FncFlags || (TypeScript.FncFlags = {}));
+    var SignatureFlags;
     (function (SignatureFlags) {
         SignatureFlags[SignatureFlags["None"] = 0] = "None";
         SignatureFlags[SignatureFlags["IsIndexer"] = 1] = "IsIndexer";
         SignatureFlags[SignatureFlags["IsStringIndexer"] = 2] = "IsStringIndexer";
         SignatureFlags[SignatureFlags["IsNumberIndexer"] = 4] = "IsNumberIndexer";
-    })(TypeScript.SignatureFlags || (TypeScript.SignatureFlags = {}));
-    var SignatureFlags = TypeScript.SignatureFlags;
+    })(SignatureFlags = TypeScript.SignatureFlags || (TypeScript.SignatureFlags = {}));
     function ToDeclFlags(fncOrVarOrSymbolOrModuleFlags) {
         return fncOrVarOrSymbolOrModuleFlags;
     }
     TypeScript.ToDeclFlags = ToDeclFlags;
+    var TypeFlags;
     (function (TypeFlags) {
         TypeFlags[TypeFlags["None"] = 0] = "None";
         TypeFlags[TypeFlags["HasImplementation"] = 1] = "HasImplementation";
@@ -484,8 +485,8 @@ var TypeScript;
         TypeFlags[TypeFlags["HasBaseType"] = 32] = "HasBaseType";
         TypeFlags[TypeFlags["HasBaseTypeOfObject"] = 64] = "HasBaseTypeOfObject";
         TypeFlags[TypeFlags["IsClass"] = 128] = "IsClass";
-    })(TypeScript.TypeFlags || (TypeScript.TypeFlags = {}));
-    var TypeFlags = TypeScript.TypeFlags;
+    })(TypeFlags = TypeScript.TypeFlags || (TypeScript.TypeFlags = {}));
+    var TypeRelationshipFlags;
     (function (TypeRelationshipFlags) {
         TypeRelationshipFlags[TypeRelationshipFlags["SuccessfulComparison"] = 0] = "SuccessfulComparison";
         TypeRelationshipFlags[TypeRelationshipFlags["SourceIsNullTargetIsVoidOrUndefined"] = 1] = "SourceIsNullTargetIsVoidOrUndefined";
@@ -495,19 +496,18 @@ var TypeScript;
         TypeRelationshipFlags[TypeRelationshipFlags["IncompatibleReturnTypes"] = 16] = "IncompatibleReturnTypes";
         TypeRelationshipFlags[TypeRelationshipFlags["IncompatiblePropertyTypes"] = 32] = "IncompatiblePropertyTypes";
         TypeRelationshipFlags[TypeRelationshipFlags["IncompatibleParameterTypes"] = 64] = "IncompatibleParameterTypes";
-    })(TypeScript.TypeRelationshipFlags || (TypeScript.TypeRelationshipFlags = {}));
-    var TypeRelationshipFlags = TypeScript.TypeRelationshipFlags;
+    })(TypeRelationshipFlags = TypeScript.TypeRelationshipFlags || (TypeScript.TypeRelationshipFlags = {}));
+    var CodeGenTarget;
     (function (CodeGenTarget) {
         CodeGenTarget[CodeGenTarget["ES3"] = 0] = "ES3";
         CodeGenTarget[CodeGenTarget["ES5"] = 1] = "ES5";
-    })(TypeScript.CodeGenTarget || (TypeScript.CodeGenTarget = {}));
-    var CodeGenTarget = TypeScript.CodeGenTarget;
+    })(CodeGenTarget = TypeScript.CodeGenTarget || (TypeScript.CodeGenTarget = {}));
+    var ModuleGenTarget;
     (function (ModuleGenTarget) {
         ModuleGenTarget[ModuleGenTarget["Synchronous"] = 0] = "Synchronous";
         ModuleGenTarget[ModuleGenTarget["Asynchronous"] = 1] = "Asynchronous";
         ModuleGenTarget[ModuleGenTarget["Local"] = 2] = "Local";
-    })(TypeScript.ModuleGenTarget || (TypeScript.ModuleGenTarget = {}));
-    var ModuleGenTarget = TypeScript.ModuleGenTarget;
+    })(ModuleGenTarget = TypeScript.ModuleGenTarget || (TypeScript.ModuleGenTarget = {}));
     // Compiler defaults to generating ES5-compliant code for
     //  - getters and setters
     TypeScript.codeGenTarget = CodeGenTarget.ES3;
diff --git a/tests/baselines/reference/parserRealSource3.js b/tests/baselines/reference/parserRealSource3.js
index 38e9028297bc9..f0e22395cfe5e 100644
--- a/tests/baselines/reference/parserRealSource3.js
+++ b/tests/baselines/reference/parserRealSource3.js
@@ -126,6 +126,7 @@ module TypeScript {
 var TypeScript;
 (function (TypeScript) {
     // Note: Any addition to the NodeType should also be supported with addition to AstWalkerDetailCallback
+    var NodeType;
     (function (NodeType) {
         NodeType[NodeType["None"] = 0] = "None";
         NodeType[NodeType["Empty"] = 1] = "Empty";
@@ -236,6 +237,5 @@ var TypeScript;
         NodeType[NodeType["Debugger"] = 106] = "Debugger";
         NodeType[NodeType["GeneralNode"] = 71] = "GeneralNode";
         NodeType[NodeType["LastAsg"] = 41] = "LastAsg";
-    })(TypeScript.NodeType || (TypeScript.NodeType = {}));
-    var NodeType = TypeScript.NodeType;
+    })(NodeType = TypeScript.NodeType || (TypeScript.NodeType = {}));
 })(TypeScript || (TypeScript = {}));
diff --git a/tests/baselines/reference/privacyLocalInternalReferenceImportWithExport.js b/tests/baselines/reference/privacyLocalInternalReferenceImportWithExport.js
index 0ab6d3e531e70..b328e8b303693 100644
--- a/tests/baselines/reference/privacyLocalInternalReferenceImportWithExport.js
+++ b/tests/baselines/reference/privacyLocalInternalReferenceImportWithExport.js
@@ -163,11 +163,11 @@ var m_private;
         return c_private;
     }());
     m_private.c_private = c_private;
+    var e_private;
     (function (e_private) {
         e_private[e_private["Happy"] = 0] = "Happy";
         e_private[e_private["Grumpy"] = 1] = "Grumpy";
-    })(m_private.e_private || (m_private.e_private = {}));
-    var e_private = m_private.e_private;
+    })(e_private = m_private.e_private || (m_private.e_private = {}));
     function f_private() {
         return new c_private();
     }
@@ -192,11 +192,11 @@ var m_public;
         return c_public;
     }());
     m_public.c_public = c_public;
+    var e_public;
     (function (e_public) {
         e_public[e_public["Happy"] = 0] = "Happy";
         e_public[e_public["Grumpy"] = 1] = "Grumpy";
-    })(m_public.e_public || (m_public.e_public = {}));
-    var e_public = m_public.e_public;
+    })(e_public = m_public.e_public || (m_public.e_public = {}));
     function f_public() {
         return new c_public();
     }
diff --git a/tests/baselines/reference/privacyLocalInternalReferenceImportWithoutExport.js b/tests/baselines/reference/privacyLocalInternalReferenceImportWithoutExport.js
index 96f7b74b474c2..7d4a80a0d29e8 100644
--- a/tests/baselines/reference/privacyLocalInternalReferenceImportWithoutExport.js
+++ b/tests/baselines/reference/privacyLocalInternalReferenceImportWithoutExport.js
@@ -164,11 +164,11 @@ define(["require", "exports"], function (require, exports) {
             return c_private;
         }());
         m_private.c_private = c_private;
+        var e_private;
         (function (e_private) {
             e_private[e_private["Happy"] = 0] = "Happy";
             e_private[e_private["Grumpy"] = 1] = "Grumpy";
-        })(m_private.e_private || (m_private.e_private = {}));
-        var e_private = m_private.e_private;
+        })(e_private = m_private.e_private || (m_private.e_private = {}));
         function f_private() {
             return new c_private();
         }
@@ -193,11 +193,11 @@ define(["require", "exports"], function (require, exports) {
             return c_public;
         }());
         m_public.c_public = c_public;
+        var e_public;
         (function (e_public) {
             e_public[e_public["Happy"] = 0] = "Happy";
             e_public[e_public["Grumpy"] = 1] = "Grumpy";
-        })(m_public.e_public || (m_public.e_public = {}));
-        var e_public = m_public.e_public;
+        })(e_public = m_public.e_public || (m_public.e_public = {}));
         function f_public() {
             return new c_public();
         }
diff --git a/tests/baselines/reference/privacyTopLevelInternalReferenceImportWithExport.js b/tests/baselines/reference/privacyTopLevelInternalReferenceImportWithExport.js
index 852ae4d3f1998..a01f1ef611f88 100644
--- a/tests/baselines/reference/privacyTopLevelInternalReferenceImportWithExport.js
+++ b/tests/baselines/reference/privacyTopLevelInternalReferenceImportWithExport.js
@@ -111,11 +111,11 @@ define(["require", "exports"], function (require, exports) {
             return c_private;
         }());
         m_private.c_private = c_private;
+        var e_private;
         (function (e_private) {
             e_private[e_private["Happy"] = 0] = "Happy";
             e_private[e_private["Grumpy"] = 1] = "Grumpy";
-        })(m_private.e_private || (m_private.e_private = {}));
-        var e_private = m_private.e_private;
+        })(e_private = m_private.e_private || (m_private.e_private = {}));
         function f_private() {
             return new c_private();
         }
@@ -140,11 +140,11 @@ define(["require", "exports"], function (require, exports) {
             return c_public;
         }());
         m_public.c_public = c_public;
+        var e_public;
         (function (e_public) {
             e_public[e_public["Happy"] = 0] = "Happy";
             e_public[e_public["Grumpy"] = 1] = "Grumpy";
-        })(m_public.e_public || (m_public.e_public = {}));
-        var e_public = m_public.e_public;
+        })(e_public = m_public.e_public || (m_public.e_public = {}));
         function f_public() {
             return new c_public();
         }
diff --git a/tests/baselines/reference/privacyTopLevelInternalReferenceImportWithoutExport.js b/tests/baselines/reference/privacyTopLevelInternalReferenceImportWithoutExport.js
index 1241165a8dcd3..2554085b94b41 100644
--- a/tests/baselines/reference/privacyTopLevelInternalReferenceImportWithoutExport.js
+++ b/tests/baselines/reference/privacyTopLevelInternalReferenceImportWithoutExport.js
@@ -112,11 +112,11 @@ define(["require", "exports"], function (require, exports) {
             return c_private;
         }());
         m_private.c_private = c_private;
+        var e_private;
         (function (e_private) {
             e_private[e_private["Happy"] = 0] = "Happy";
             e_private[e_private["Grumpy"] = 1] = "Grumpy";
-        })(m_private.e_private || (m_private.e_private = {}));
-        var e_private = m_private.e_private;
+        })(e_private = m_private.e_private || (m_private.e_private = {}));
         function f_private() {
             return new c_private();
         }
@@ -141,11 +141,11 @@ define(["require", "exports"], function (require, exports) {
             return c_public;
         }());
         m_public.c_public = c_public;
+        var e_public;
         (function (e_public) {
             e_public[e_public["Happy"] = 0] = "Happy";
             e_public[e_public["Grumpy"] = 1] = "Grumpy";
-        })(m_public.e_public || (m_public.e_public = {}));
-        var e_public = m_public.e_public;
+        })(e_public = m_public.e_public || (m_public.e_public = {}));
         function f_public() {
             return new c_public();
         }
diff --git a/tests/baselines/reference/scannerEnum1.js b/tests/baselines/reference/scannerEnum1.js
index e785a07ace2f6..5d8b506e62f02 100644
--- a/tests/baselines/reference/scannerEnum1.js
+++ b/tests/baselines/reference/scannerEnum1.js
@@ -6,8 +6,8 @@
 
 //// [scannerEnum1.js]
 "use strict";
+var CodeGenTarget;
 (function (CodeGenTarget) {
     CodeGenTarget[CodeGenTarget["ES3"] = 0] = "ES3";
     CodeGenTarget[CodeGenTarget["ES5"] = 1] = "ES5";
-})(exports.CodeGenTarget || (exports.CodeGenTarget = {}));
-var CodeGenTarget = exports.CodeGenTarget;
+})(CodeGenTarget = exports.CodeGenTarget || (exports.CodeGenTarget = {}));
diff --git a/tests/baselines/reference/systemModuleConstEnumsSeparateCompilation.js b/tests/baselines/reference/systemModuleConstEnumsSeparateCompilation.js
index 0cd6f472bdbc6..ca68d952ab3ab 100644
--- a/tests/baselines/reference/systemModuleConstEnumsSeparateCompilation.js
+++ b/tests/baselines/reference/systemModuleConstEnumsSeparateCompilation.js
@@ -29,10 +29,10 @@ System.register([], function (exports_1, context_1) {
                 TopLevelConstEnum[TopLevelConstEnum["X"] = 0] = "X";
             })(TopLevelConstEnum || (TopLevelConstEnum = {}));
             (function (M) {
+                var NonTopLevelConstEnum;
                 (function (NonTopLevelConstEnum) {
                     NonTopLevelConstEnum[NonTopLevelConstEnum["X"] = 0] = "X";
-                })(M.NonTopLevelConstEnum || (M.NonTopLevelConstEnum = {}));
-                var NonTopLevelConstEnum = M.NonTopLevelConstEnum;
+                })(NonTopLevelConstEnum = M.NonTopLevelConstEnum || (M.NonTopLevelConstEnum = {}));
             })(M || (M = {}));
         }
     };
diff --git a/tests/baselines/reference/systemModuleDeclarationMerging.js b/tests/baselines/reference/systemModuleDeclarationMerging.js
index 4dac69c2641b2..88b1b20149512 100644
--- a/tests/baselines/reference/systemModuleDeclarationMerging.js
+++ b/tests/baselines/reference/systemModuleDeclarationMerging.js
@@ -34,7 +34,7 @@ System.register([], function (exports_1, context_1) {
             })(C = C || (C = {}));
             exports_1("C", C);
             (function (E) {
-            })(E || (E = {}));
+            })(E = E || (E = {}));
             exports_1("E", E);
             (function (E) {
                 var x;
diff --git a/tests/baselines/reference/systemModuleNonTopLevelModuleMembers.js b/tests/baselines/reference/systemModuleNonTopLevelModuleMembers.js
index b0498b23f79ac..db907c49d911b 100644
--- a/tests/baselines/reference/systemModuleNonTopLevelModuleMembers.js
+++ b/tests/baselines/reference/systemModuleNonTopLevelModuleMembers.js
@@ -34,7 +34,7 @@ System.register([], function (exports_1, context_1) {
             exports_1("TopLevelModule", TopLevelModule);
             (function (TopLevelEnum) {
                 TopLevelEnum[TopLevelEnum["E"] = 0] = "E";
-            })(TopLevelEnum || (TopLevelEnum = {}));
+            })(TopLevelEnum = TopLevelEnum || (TopLevelEnum = {}));
             exports_1("TopLevelEnum", TopLevelEnum);
             (function (TopLevelModule2) {
                 var NonTopLevelClass = (function () {
@@ -49,10 +49,10 @@ System.register([], function (exports_1, context_1) {
                 })(NonTopLevelModule = TopLevelModule2.NonTopLevelModule || (TopLevelModule2.NonTopLevelModule = {}));
                 function NonTopLevelFunction() { }
                 TopLevelModule2.NonTopLevelFunction = NonTopLevelFunction;
+                var NonTopLevelEnum;
                 (function (NonTopLevelEnum) {
                     NonTopLevelEnum[NonTopLevelEnum["E"] = 0] = "E";
-                })(TopLevelModule2.NonTopLevelEnum || (TopLevelModule2.NonTopLevelEnum = {}));
-                var NonTopLevelEnum = TopLevelModule2.NonTopLevelEnum;
+                })(NonTopLevelEnum = TopLevelModule2.NonTopLevelEnum || (TopLevelModule2.NonTopLevelEnum = {}));
             })(TopLevelModule2 = TopLevelModule2 || (TopLevelModule2 = {}));
             exports_1("TopLevelModule2", TopLevelModule2);
         }
diff --git a/tests/baselines/reference/typeofAnExportedType.js b/tests/baselines/reference/typeofAnExportedType.js
index 91b19d9bebd46..69602d3e4c339 100644
--- a/tests/baselines/reference/typeofAnExportedType.js
+++ b/tests/baselines/reference/typeofAnExportedType.js
@@ -74,10 +74,10 @@ var M;
     M.C = C;
 })(M = exports.M || (exports.M = {}));
 exports.Z = M;
+var E;
 (function (E) {
     E[E["A"] = 0] = "A";
-})(exports.E || (exports.E = {}));
-var E = exports.E;
+})(E = exports.E || (exports.E = {}));
 function foo() { }
 exports.foo = foo;
 (function (foo) {

From b557211a375bd47d11b42aa6ee29f5c741439fb3 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 13 Oct 2016 13:02:22 -0700
Subject: [PATCH 055/224] Return both ts and js results from module resolution,
 and don't have moduleNameResolver responsible for omitting files based on
 compiler options

---
 src/compiler/checker.ts                       |  18 +-
 src/compiler/core.ts                          |   6 +-
 src/compiler/diagnosticMessages.json          |  12 +-
 src/compiler/moduleNameResolver.ts            | 314 +++++++++++-------
 src/compiler/program.ts                       |  65 ++--
 src/compiler/types.ts                         |  33 +-
 src/compiler/utilities.ts                     |  30 +-
 src/harness/unittests/moduleResolution.ts     | 253 +++++++++++---
 .../unittests/reuseProgramStructure.ts        |  17 +-
 src/server/lsHost.ts                          |  51 +--
 .../typingsInstaller/typingsInstaller.ts      |   4 +-
 src/services/shims.ts                         |   2 +-
 ...portWithTrailingSlash_noResolve.trace.json |   2 +
 .../reference/library-reference-11.trace.json |   5 -
 .../reference/library-reference-12.trace.json |   5 -
 .../reference/library-reference-3.trace.json  |   2 -
 .../reference/library-reference-4.trace.json  |  16 -
 .../reference/library-reference-5.trace.json  |  16 -
 .../reference/library-reference-7.trace.json  |   2 -
 .../reference/moduleResolutionNoTs.js         |   2 +-
 .../moduleResolutionWithExtensions.trace.json |   4 +
 ...tionWithExtensions_notSupported.errors.txt |  23 ++
 ...leResolutionWithExtensions_notSupported.js |  17 +
 ...tionWithExtensions_notSupported.trace.json |  40 +++
 ...ionWithExtensions_notSupported2.errors.txt |  12 +
 ...eResolutionWithExtensions_notSupported2.js |  12 +
 ...ionWithExtensions_notSupported2.trace.json |  18 +
 ...moduleResolutionWithExtensions_preferTs.js |  18 +
 ...eResolutionWithExtensions_preferTs.symbols |   8 +
 ...solutionWithExtensions_preferTs.trace.json |  14 +
 ...uleResolutionWithExtensions_preferTs.types |   8 +
 ...lutionWithExtensions_withAmbientPresent.js |  18 +
 ...nWithExtensions_withAmbientPresent.symbols |  11 +
 ...thExtensions_withAmbientPresent.trace.json |  28 ++
 ...ionWithExtensions_withAmbientPresent.types |  12 +
 .../moduleResolutionWithSymlinks.trace.json   |  28 ++
 ...gBasedModuleResolution3_classic.trace.json |   9 +
 ...pingBasedModuleResolution3_node.trace.json |  22 ++
 ...gBasedModuleResolution4_classic.trace.json |   9 +
 ...pingBasedModuleResolution4_node.trace.json |  22 ++
 ...gBasedModuleResolution5_classic.trace.json |  15 +
 ...pingBasedModuleResolution5_node.trace.json |  30 ++
 ...gBasedModuleResolution6_classic.trace.json |   7 +
 ...pingBasedModuleResolution6_node.trace.json |  10 +
 ...gBasedModuleResolution7_classic.trace.json |  24 ++
 ...pingBasedModuleResolution7_node.trace.json |  40 +++
 ...mMultipleNodeModulesDirectories.trace.json |  72 ++++
 ...romNodeModulesInParentDirectory.trace.json |  16 +
 .../reference/typingsLookup4.trace.json       |  35 +-
 .../reference/typingsLookupAmd.trace.json     |  56 ++++
 tests/cases/compiler/moduleResolutionNoTs.ts  |   1 +
 ...leResolutionWithExtensions_notSupported.ts |  13 +
 ...eResolutionWithExtensions_notSupported2.ts |   9 +
 ...moduleResolutionWithExtensions_preferTs.ts |  10 +
 ...lutionWithExtensions_withAmbientPresent.ts |  14 +
 .../references/library-reference-11.ts        |   1 +
 56 files changed, 1223 insertions(+), 318 deletions(-)
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_notSupported.errors.txt
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_notSupported.js
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_notSupported.trace.json
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.errors.txt
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.js
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.trace.json
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_preferTs.js
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_preferTs.symbols
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_preferTs.trace.json
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_preferTs.types
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.js
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.symbols
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.trace.json
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.types
 create mode 100644 tests/cases/compiler/moduleResolutionWithExtensions_notSupported.ts
 create mode 100644 tests/cases/compiler/moduleResolutionWithExtensions_notSupported2.ts
 create mode 100644 tests/cases/compiler/moduleResolutionWithExtensions_preferTs.ts
 create mode 100644 tests/cases/compiler/moduleResolutionWithExtensions_withAmbientPresent.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index d3f15f2367bc6..ebf86484c4505 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -1366,7 +1366,8 @@ namespace ts {
             }
 
             const resolvedModule = getResolvedModule(getSourceFileOfNode(location), moduleReference);
-            const sourceFile = resolvedModule && host.getSourceFile(resolvedModule.resolvedFileName);
+            const resolvedOrDiagnostic = resolvedModule && getResolutionOrDiagnostic(compilerOptions, resolvedModule);
+            const sourceFile = typeof resolvedOrDiagnostic === "string" && resolvedModule && host.getSourceFile(resolvedModule.resolvedFileName);
             if (sourceFile) {
                 if (sourceFile.symbol) {
                     // merged symbol is module declaration symbol combined with all augmentations
@@ -1388,13 +1389,18 @@ namespace ts {
 
             if (moduleNotFoundError) {
                 // report errors only if it was requested
-                const tsExtension = tryExtractTypeScriptExtension(moduleName);
-                if (tsExtension) {
-                    const diag = Diagnostics.An_import_path_cannot_end_with_a_0_extension_Consider_importing_1_instead;
-                    error(errorNode, diag, tsExtension, removeExtension(moduleName, tsExtension));
+                if (resolvedOrDiagnostic && typeof resolvedOrDiagnostic !== "string") {
+                    error(errorNode, resolvedOrDiagnostic.diag, moduleName, resolvedOrDiagnostic.file);
                 }
                 else {
-                    error(errorNode, moduleNotFoundError, moduleName);
+                    const tsExtension = tryExtractTypeScriptExtension(moduleName);
+                    if (tsExtension) {
+                        const diag = Diagnostics.An_import_path_cannot_end_with_a_0_extension_Consider_importing_1_instead;
+                        error(errorNode, diag, tsExtension, removeExtension(moduleName, tsExtension));
+                    }
+                    else {
+                        error(errorNode, moduleNotFoundError, moduleName);
+                    }
                 }
             }
             return undefined;
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index befa30b600618..66179a8ce3a92 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -1753,7 +1753,7 @@ namespace ts {
     /** Must have ".d.ts" first because if ".ts" goes first, that will be detected as the extension instead of ".d.ts". */
     export const supportedTypescriptExtensionsForExtractExtension = [".d.ts", ".ts", ".tsx"];
     export const supportedJavascriptExtensions = [".js", ".jsx"];
-    const allSupportedExtensions  = supportedTypeScriptExtensions.concat(supportedJavascriptExtensions);
+    export const allSupportedExtensions  = supportedTypeScriptExtensions.concat(supportedJavascriptExtensions);
 
     export function getSupportedExtensions(options?: CompilerOptions): string[] {
         return options && options.allowJs ? allSupportedExtensions : supportedTypeScriptExtensions;
@@ -1850,10 +1850,6 @@ namespace ts {
         return path.substring(0, path.length - extension.length);
     }
 
-    export function isJsxOrTsxExtension(ext: string): boolean {
-        return ext === ".jsx" || ext === ".tsx";
-    }
-
     export function changeExtension<T extends string | Path>(path: T, newExtension: string): T {
         return <T>(removeFileExtension(path) + newExtension);
     }
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 21f04da488d9b..5629e1e270f54 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -2697,7 +2697,7 @@
         "category": "Message",
         "code": 6099
     },
-    "'package.json' does not have 'types' field.": {
+    "'package.json' does not have a 'types' or 'main' field.": {
         "category": "Message",
         "code": 6100
     },
@@ -2845,7 +2845,7 @@
         "category": "Message",
         "code": 6136
     },
-    "No types specified in 'package.json' but 'allowJs' is set, so returning 'main' value of '{0}'": {
+    "No types specified in 'package.json', so returning 'main' value of '{0}'": {
         "category": "Message",
         "code": 6137
     },
@@ -2865,6 +2865,14 @@
         "category": "Message",
         "code": 6141
     },
+    "Module '{0}' was resolved to '{1}', but '--jsx' is not set.": {
+        "category": "Error",
+        "code": 6142
+    },
+    "Module '{0}' was resolved to '{1}', but '--allowJs' is not set.": {
+        "category": "Error",
+        "code": 6143
+    },
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005
diff --git a/src/compiler/moduleNameResolver.ts b/src/compiler/moduleNameResolver.ts
index 4ebdc59e6ddfd..b7b322096a8b8 100644
--- a/src/compiler/moduleNameResolver.ts
+++ b/src/compiler/moduleNameResolver.ts
@@ -2,10 +2,8 @@
 /// <reference path="diagnosticInformationMap.generated.ts" />
 
 namespace ts {
-
-    /* @internal */
-    export function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void;
-    export function trace(host: ModuleResolutionHost, message: DiagnosticMessage): void {
+    function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void;
+    function trace(host: ModuleResolutionHost, message: DiagnosticMessage): void {
         host.trace(formatMessage.apply(undefined, arguments));
     }
 
@@ -14,22 +12,102 @@ namespace ts {
         return compilerOptions.traceResolution && host.trace !== undefined;
     }
 
+    /**
+     * Result of trying to resolve a module.
+     * At least one of `ts` and `js` should be defined, or the whole thing should be `undefined`.
+     */
+    interface Resolved {
+        ts: string | undefined;
+        js: string | undefined;
+    }
+
+    /**
+     * Given a resolution result which does not have a resolvedTsFileName, combine it with second attempt.
+     * This should be used in the following pattern:
+     *
+     * const attemptA = foo();
+     * return attemptA && attemptA.ts ? attemptA : combineAttempts(attemptA, bar());
+     *
+     * Meaning, we stop early if we found a typed result.
+     */
+    function combineAttempts(firstAttempt: Resolved | undefined, secondAttempt: Resolved | undefined): Resolved | undefined {
+        Debug.assert(!(firstAttempt && firstAttempt.ts));
+        return firstAttempt && secondAttempt
+            ? { ts: secondAttempt.ts, js: firstAttempt.js }
+            : (firstAttempt || secondAttempt);
+    }
+
+    /**
+     * Whether we are looking for all supported extensions or only `.d.ts` files.
+     * We look for tsx/jsx/js files even if the compiler settings do not allow them -- this will be a checker error.
+     */
+    enum Extensions { All, DtsOnly }
+
+    /** Used with `Extensions.DtsOnly` to use just the `ts` component, since `js` can't possibly be defined. */
+    function resolvedTsOnly(resolved: Resolved | undefined): string | undefined {
+        Debug.assert(!(resolved && resolved.js));
+        return resolved && resolved.ts;
+    }
+
+    /** Create Resolved from a file with unknown extension. */
+    function resolvedFromAnyFile(path: string): Resolved | undefined {
+        return fileExtensionIsAny(path, supportedTypeScriptExtensions) ? { ts: path, js: undefined } : { ts: undefined, js: path };
+    }
+
     /* @internal */
-    export function createResolvedModule(resolvedFileName: string, isExternalLibraryImport: boolean, failedLookupLocations: string[]): ResolvedModuleWithFailedLookupLocations {
-        return { resolvedModule: resolvedFileName ? { resolvedFileName, isExternalLibraryImport } : undefined, failedLookupLocations };
+    export function resolvedModuleFromAnyFile(fileName: string, isExternalLibraryImport: boolean): ResolvedModule {
+        return resolvedModuleFromResolved(resolvedFromAnyFile(fileName), isExternalLibraryImport);
+    }
+
+    /** Adds `isExernalLibraryImport` to a Resolved to get a ResolvedModule. */
+    function resolvedModuleFromResolved({ ts, js }: Resolved, isExternalLibraryImport: boolean): ResolvedModule {
+        return { resolvedFileName: ts || js, resolvedTsFileName: ts, resolvedJsFileName: js, isExternalLibraryImport };
+    }
+
+    function createResolvedModuleWithFailedLookupLocations(resolved: Resolved | undefined, isExternalLibraryImport: boolean, failedLookupLocations: string[]): ResolvedModuleWithFailedLookupLocations {
+        return { resolvedModule: resolved && resolvedModuleFromResolved(resolved, isExternalLibraryImport), failedLookupLocations };
     }
 
     function moduleHasNonRelativeName(moduleName: string): boolean {
         return !(isRootedDiskPath(moduleName) || isExternalModuleNameRelative(moduleName));
     }
 
-    /* @internal */
-    export interface ModuleResolutionState {
+    interface ModuleResolutionState {
         host: ModuleResolutionHost;
-        compilerOptions: CompilerOptions;
+        // We only use this subset of the compiler options.
+        compilerOptions: { rootDirs?: string[], baseUrl?: string, paths?: MapLike<string[]>; };
         traceEnabled: boolean;
-        // skip .tsx files if jsx is not enabled
-        skipTsx: boolean;
+    }
+
+    /** LsHost uses a global cache of automatically-installed typings to help it resolve modules. */
+    /* @internal */
+    export function resolveModuleNameForLsHost(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost, globalCache: string | undefined, projectName: string): ResolvedModuleWithFailedLookupLocations {
+        const primaryResult = resolveModuleName(moduleName, containingFile, compilerOptions, host);
+        if (primaryResult.resolvedModule && primaryResult.resolvedModule.resolvedTsFileName) {
+            // return result immediately only if it is .ts, .tsx or .d.ts
+            // otherwise try to load typings from @types
+            return primaryResult;
+        }
+
+        // create different collection of failed lookup locations for second pass
+        // if it will fail and we've already found something during the first pass - we don't want to pollute its results
+        const secondaryLookupFailedLookupLocations: string[] = [];
+        if (globalCache !== undefined) {
+            const traceEnabled = isTraceEnabled(compilerOptions, host);
+            if (traceEnabled) {
+                trace(host, Diagnostics.Auto_discovery_for_typings_is_enabled_in_project_0_Running_extra_resolution_pass_for_module_1_using_cache_location_2, projectName, moduleName, globalCache);
+            }
+            const state: ModuleResolutionState = { compilerOptions, host, traceEnabled };
+            const resolved = loadModuleFromNodeModules(Extensions.All, moduleName, globalCache, secondaryLookupFailedLookupLocations, state, /*checkOneLevel*/ true);
+            if (resolved) {
+                return createResolvedModuleWithFailedLookupLocations(resolved, /*isExternalLibraryImport*/ true, primaryResult.failedLookupLocations.concat(secondaryLookupFailedLookupLocations));
+            }
+        }
+
+        if (!primaryResult.resolvedModule && secondaryLookupFailedLookupLocations.length) {
+            primaryResult.failedLookupLocations = primaryResult.failedLookupLocations.concat(secondaryLookupFailedLookupLocations);
+        }
+        return primaryResult;
     }
 
     function tryReadTypesSection(packageJsonPath: string, baseDirectory: string, state: ModuleResolutionState): string {
@@ -59,12 +137,11 @@ namespace ts {
         }
 
         // Use the main module for inferring types if no types package specified and the allowJs is set
-        if (state.compilerOptions.allowJs && jsonContent.main && typeof jsonContent.main === "string") {
+        if (typeof jsonContent.main === "string") {
             if (state.traceEnabled) {
-                trace(state.host, Diagnostics.No_types_specified_in_package_json_but_allowJs_is_set_so_returning_main_value_of_0, jsonContent.main);
+                trace(state.host, Diagnostics.No_types_specified_in_package_json_so_returning_main_value_of_0, jsonContent.main);
             }
-            const mainFilePath = normalizePath(combinePaths(baseDirectory, jsonContent.main));
-            return mainFilePath;
+            return normalizePath(combinePaths(baseDirectory, jsonContent.main));
         }
         return undefined;
     }
@@ -80,8 +157,6 @@ namespace ts {
         }
     }
 
-    const typeReferenceExtensions = [".d.ts"];
-
     export function getEffectiveTypeRoots(options: CompilerOptions, host: { directoryExists?: (directoryName: string) => boolean, getCurrentDirectory?: () => string }): string[] | undefined {
         if (options.typeRoots) {
             return options.typeRoots;
@@ -132,12 +207,11 @@ namespace ts {
      * This is possible in case if resolution is performed for directives specified via 'types' parameter. In this case initial path for secondary lookups
      * is assumed to be the same as root directory of the project.
      */
-    export function resolveTypeReferenceDirective(typeReferenceDirectiveName: string, containingFile: string, options: CompilerOptions, host: ModuleResolutionHost): ResolvedTypeReferenceDirectiveWithFailedLookupLocations {
+    export function resolveTypeReferenceDirective(typeReferenceDirectiveName: string, containingFile: string | undefined, options: CompilerOptions, host: ModuleResolutionHost): ResolvedTypeReferenceDirectiveWithFailedLookupLocations {
         const traceEnabled = isTraceEnabled(options, host);
         const moduleResolutionState: ModuleResolutionState = {
             compilerOptions: options,
             host: host,
-            skipTsx: true,
             traceEnabled
         };
 
@@ -168,19 +242,20 @@ namespace ts {
             if (traceEnabled) {
                 trace(host, Diagnostics.Resolving_with_primary_search_path_0, typeRoots.join(", "));
             }
-            const primarySearchPaths = typeRoots;
-            for (const typeRoot of primarySearchPaths) {
+            for (const typeRoot of typeRoots) {
                 const candidate = combinePaths(typeRoot, typeReferenceDirectiveName);
                 const candidateDirectory = getDirectoryPath(candidate);
-                const resolvedFile = loadNodeModuleFromDirectory(typeReferenceExtensions, candidate, failedLookupLocations,
-                    !directoryProbablyExists(candidateDirectory, host), moduleResolutionState);
 
-                if (resolvedFile) {
+                const resolved = resolvedTsOnly(
+                    loadNodeModuleFromDirectory(Extensions.DtsOnly, candidate, failedLookupLocations,
+                        !directoryProbablyExists(candidateDirectory, host), moduleResolutionState));
+
+                if (resolved) {
                     if (traceEnabled) {
-                        trace(host, Diagnostics.Type_reference_directive_0_was_successfully_resolved_to_1_primary_Colon_2, typeReferenceDirectiveName, resolvedFile, true);
+                        trace(host, Diagnostics.Type_reference_directive_0_was_successfully_resolved_to_1_primary_Colon_2, typeReferenceDirectiveName, resolved, true);
                     }
                     return {
-                        resolvedTypeReferenceDirective: { primary: true, resolvedFileName: resolvedFile },
+                        resolvedTypeReferenceDirective: { primary: true, resolvedFileName: resolved },
                         failedLookupLocations
                     };
                 }
@@ -193,17 +268,14 @@ namespace ts {
         }
 
         let resolvedFile: string;
-        let initialLocationForSecondaryLookup: string;
-        if (containingFile) {
-            initialLocationForSecondaryLookup = getDirectoryPath(containingFile);
-        }
+        const initialLocationForSecondaryLookup = containingFile && getDirectoryPath(containingFile);
 
         if (initialLocationForSecondaryLookup !== undefined) {
             // check secondary locations
             if (traceEnabled) {
                 trace(host, Diagnostics.Looking_up_in_node_modules_folder_initial_location_0, initialLocationForSecondaryLookup);
             }
-            resolvedFile = loadModuleFromNodeModules(typeReferenceDirectiveName, initialLocationForSecondaryLookup, failedLookupLocations, moduleResolutionState, /*checkOneLevel*/ false);
+            resolvedFile = resolvedTsOnly(loadModuleFromNodeModules(Extensions.DtsOnly, typeReferenceDirectiveName, initialLocationForSecondaryLookup, failedLookupLocations, moduleResolutionState, /*checkOneLevel*/ false));
             if (traceEnabled) {
                 if (resolvedFile) {
                     trace(host, Diagnostics.Type_reference_directive_0_was_successfully_resolved_to_1_primary_Colon_2, typeReferenceDirectiveName, resolvedFile, false);
@@ -219,9 +291,7 @@ namespace ts {
             }
         }
         return {
-            resolvedTypeReferenceDirective: resolvedFile
-                ? { primary: false, resolvedFileName: resolvedFile }
-                : undefined,
+            resolvedTypeReferenceDirective: resolvedFile ? { primary: false, resolvedFileName: resolvedFile } : undefined,
             failedLookupLocations
         };
     }
@@ -313,7 +383,7 @@ namespace ts {
      * 'typings' entry or file 'index' with some supported extension
      * - Classic loader will only try to interpret '/a/b/c' as file.
      */
-    type ResolutionKindSpecificLoader = (candidate: string, extensions: string[], failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState) => string;
+    type ResolutionKindSpecificLoader = (candidate: string, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState) => Resolved | undefined;
 
     /**
      * Any module resolution kind can be augmented with optional settings: 'baseUrl', 'paths' and 'rootDirs' - they are used to
@@ -376,18 +446,18 @@ namespace ts {
      * entries in 'rootDirs', use them to build absolute path out of (*) and try to resolve module from this location.
      */
     function tryLoadModuleUsingOptionalResolutionSettings(moduleName: string, containingDirectory: string, loader: ResolutionKindSpecificLoader,
-        failedLookupLocations: string[], supportedExtensions: string[], state: ModuleResolutionState): string {
+        failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
 
         if (moduleHasNonRelativeName(moduleName)) {
-            return tryLoadModuleUsingBaseUrl(moduleName, loader, failedLookupLocations, supportedExtensions, state);
+            return tryLoadModuleUsingBaseUrl(moduleName, loader, failedLookupLocations, state);
         }
         else {
-            return tryLoadModuleUsingRootDirs(moduleName, containingDirectory, loader, failedLookupLocations, supportedExtensions, state);
+            return tryLoadModuleUsingRootDirs(moduleName, containingDirectory, loader, failedLookupLocations, state);
         }
     }
 
     function tryLoadModuleUsingRootDirs(moduleName: string, containingDirectory: string, loader: ResolutionKindSpecificLoader,
-        failedLookupLocations: string[], supportedExtensions: string[], state: ModuleResolutionState): string {
+        failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
 
         if (!state.compilerOptions.rootDirs) {
             return undefined;
@@ -432,7 +502,7 @@ namespace ts {
             if (state.traceEnabled) {
                 trace(state.host, Diagnostics.Loading_0_from_the_root_dir_1_candidate_location_2, suffix, matchedNormalizedPrefix, candidate);
             }
-            const resolvedFileName = loader(candidate, supportedExtensions, failedLookupLocations, !directoryProbablyExists(containingDirectory, state.host), state);
+            const resolvedFileName = loader(candidate, failedLookupLocations, !directoryProbablyExists(containingDirectory, state.host), state);
             if (resolvedFileName) {
                 return resolvedFileName;
             }
@@ -451,7 +521,7 @@ namespace ts {
                     trace(state.host, Diagnostics.Loading_0_from_the_root_dir_1_candidate_location_2, suffix, rootDir, candidate);
                 }
                 const baseDirectory = getDirectoryPath(candidate);
-                const resolvedFileName = loader(candidate, supportedExtensions, failedLookupLocations, !directoryProbablyExists(baseDirectory, state.host), state);
+                const resolvedFileName = loader(candidate, failedLookupLocations, !directoryProbablyExists(baseDirectory, state.host), state);
                 if (resolvedFileName) {
                     return resolvedFileName;
                 }
@@ -463,9 +533,7 @@ namespace ts {
         return undefined;
     }
 
-    function tryLoadModuleUsingBaseUrl(moduleName: string, loader: ResolutionKindSpecificLoader, failedLookupLocations: string[],
-        supportedExtensions: string[], state: ModuleResolutionState): string {
-
+    function tryLoadModuleUsingBaseUrl(moduleName: string, loader: ResolutionKindSpecificLoader, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
         if (!state.compilerOptions.baseUrl) {
             return undefined;
         }
@@ -494,9 +562,9 @@ namespace ts {
                 if (state.traceEnabled) {
                     trace(state.host, Diagnostics.Trying_substitution_0_candidate_module_location_Colon_1, subst, path);
                 }
-                const resolvedFileName = loader(candidate, supportedExtensions, failedLookupLocations, !directoryProbablyExists(getDirectoryPath(candidate), state.host), state);
-                if (resolvedFileName) {
-                    return resolvedFileName;
+                const resolved = loader(candidate, failedLookupLocations, !directoryProbablyExists(getDirectoryPath(candidate), state.host), state);
+                if (resolved) {
+                    return resolved;
                 }
             }
             return undefined;
@@ -508,56 +576,58 @@ namespace ts {
                 trace(state.host, Diagnostics.Resolving_module_name_0_relative_to_base_url_1_2, moduleName, state.compilerOptions.baseUrl, candidate);
             }
 
-            return loader(candidate, supportedExtensions, failedLookupLocations, !directoryProbablyExists(getDirectoryPath(candidate), state.host), state);
+            return loader(candidate, failedLookupLocations, !directoryProbablyExists(getDirectoryPath(candidate), state.host), state);
         }
     }
 
     export function nodeModuleNameResolver(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost): ResolvedModuleWithFailedLookupLocations {
         const containingDirectory = getDirectoryPath(containingFile);
-        const supportedExtensions = getSupportedExtensions(compilerOptions);
         const traceEnabled = isTraceEnabled(compilerOptions, host);
 
         const failedLookupLocations: string[] = [];
-        const state = { compilerOptions, host, traceEnabled, skipTsx: false };
-        let resolvedFileName = tryLoadModuleUsingOptionalResolutionSettings(moduleName, containingDirectory, nodeLoadModuleByRelativeName,
-            failedLookupLocations, supportedExtensions, state);
+        const state: ModuleResolutionState = { compilerOptions, host, traceEnabled };
+        let resolved = tryLoadModuleUsingOptionalResolutionSettings(moduleName, containingDirectory, nodeLoadModuleByRelativeName, failedLookupLocations, state);
 
         let isExternalLibraryImport = false;
-        if (!resolvedFileName) {
+        if (!resolved) {
             if (moduleHasNonRelativeName(moduleName)) {
                 if (traceEnabled) {
                     trace(host, Diagnostics.Loading_module_0_from_node_modules_folder, moduleName);
                 }
-                resolvedFileName = loadModuleFromNodeModules(moduleName, containingDirectory, failedLookupLocations, state, /*checkOneLevel*/ false);
-                isExternalLibraryImport = resolvedFileName !== undefined;
+                resolved = loadModuleFromNodeModules(Extensions.All, moduleName, containingDirectory, failedLookupLocations, state, /*checkOneLevel*/ false);
+                isExternalLibraryImport = resolved !== undefined;
             }
             else {
                 const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
-                resolvedFileName = nodeLoadModuleByRelativeName(candidate, supportedExtensions, failedLookupLocations, /*onlyRecordFailures*/ false, state);
+                resolved = nodeLoadModuleByRelativeName(candidate, failedLookupLocations, /*onlyRecordFailures*/ false, state);
             }
         }
 
-        if (resolvedFileName && host.realpath) {
-            const originalFileName = resolvedFileName;
-            resolvedFileName = normalizePath(host.realpath(resolvedFileName));
+        return createResolvedModuleWithFailedLookupLocations(resolved && resolvedWithRealpath(resolved, host, traceEnabled), isExternalLibraryImport, failedLookupLocations);
+    }
+
+    function resolvedWithRealpath(resolved: Resolved, host: ModuleResolutionHost, traceEnabled: boolean): Resolved {
+        return host.realpath ? { ts: resolved.ts && realpath(resolved.ts), js: resolved.js && realpath(resolved.js) } : resolved;
+
+        function realpath(path: string): string {
+            const real = normalizePath(host.realpath(path));
             if (traceEnabled) {
-                trace(host, Diagnostics.Resolving_real_path_for_0_result_1, originalFileName, resolvedFileName);
+                trace(host, Diagnostics.Resolving_real_path_for_0_result_1, path, real);
             }
+            return real;
         }
-
-        return createResolvedModule(resolvedFileName, isExternalLibraryImport, failedLookupLocations);
     }
 
-    function nodeLoadModuleByRelativeName(candidate: string, supportedExtensions: string[], failedLookupLocations: string[],
-        onlyRecordFailures: boolean, state: ModuleResolutionState): string {
-
+    function nodeLoadModuleByRelativeName(candidate: string, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
         if (state.traceEnabled) {
             trace(state.host, Diagnostics.Loading_module_as_file_Slash_folder_candidate_module_location_0, candidate);
         }
 
-        const resolvedFileName = !pathEndsWithDirectorySeparator(candidate) && loadModuleFromFile(candidate, supportedExtensions, failedLookupLocations, onlyRecordFailures, state);
-
-        return resolvedFileName || loadNodeModuleFromDirectory(supportedExtensions, candidate, failedLookupLocations, onlyRecordFailures, state);
+        const resolvedFromFile = !pathEndsWithDirectorySeparator(candidate) && loadModuleFromFile(Extensions.All, candidate, failedLookupLocations, onlyRecordFailures, state);
+        return resolvedFromFile && resolvedFromFile.ts
+            ? resolvedFromFile
+            : combineAttempts(resolvedFromFile,
+                loadNodeModuleFromDirectory(Extensions.All, candidate, failedLookupLocations, onlyRecordFailures, state));
     }
 
     /* @internal */
@@ -566,13 +636,17 @@ namespace ts {
         return !host.directoryExists || host.directoryExists(directoryName);
     }
 
+    function loadModuleFromFileAnyExtension(candidate: string, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
+        return loadModuleFromFile(Extensions.All, candidate, failedLookupLocations, onlyRecordFailures, state);
+    }
+
     /**
      * @param {boolean} onlyRecordFailures - if true then function won't try to actually load files but instead record all attempts as failures. This flag is necessary
      * in cases when we know upfront that all load attempts will fail (because containing folder does not exists) however we still need to record all failed lookup locations.
      */
-    function loadModuleFromFile(candidate: string, extensions: string[], failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string | undefined {
+    function loadModuleFromFile(extensions: Extensions, candidate: string, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
         // First, try adding an extension. An import of "foo" could be matched by a file "foo.ts", or "foo.js" by "foo.js.ts"
-        const resolvedByAddingExtension = tryAddingExtensions(candidate, extensions, failedLookupLocation, onlyRecordFailures, state);
+        const resolvedByAddingExtension = tryAddingExtensions(candidate, extensions, failedLookupLocations, onlyRecordFailures, state);
         if (resolvedByAddingExtension) {
             return resolvedByAddingExtension;
         }
@@ -585,12 +659,12 @@ namespace ts {
                 const extension = candidate.substring(extensionless.length);
                 trace(state.host, Diagnostics.File_name_0_has_a_1_extension_stripping_it, candidate, extension);
             }
-            return tryAddingExtensions(extensionless, extensions, failedLookupLocation, onlyRecordFailures, state);
+            return tryAddingExtensions(extensionless, Extensions.All, failedLookupLocations, onlyRecordFailures, state);
         }
     }
 
     /** Try to return an existing file that adds one of the `extensions` to `candidate`. */
-    function tryAddingExtensions(candidate: string, extensions: string[], failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string | undefined {
+    function tryAddingExtensions(candidate: string, extensions: Extensions, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
         if (!onlyRecordFailures) {
             // check if containing folder exists - if it doesn't then just record failures for all supported extensions without disk probing
             const directory = getDirectoryPath(candidate);
@@ -598,8 +672,26 @@ namespace ts {
                 onlyRecordFailures = !directoryProbablyExists(directory, state.host);
             }
         }
-        return forEach(extensions, ext =>
-            !(state.skipTsx && isJsxOrTsxExtension(ext)) && tryFile(candidate + ext, failedLookupLocation, onlyRecordFailures, state));
+
+        switch (extensions) {
+            case Extensions.DtsOnly: {
+                const dts = tryExtension(".d.ts");
+                return dts && { ts: dts, js: undefined };
+            }
+            case Extensions.All: {
+                const ts = forEach(supportedTypeScriptExtensions, tryExtension);
+                if (ts) {
+                    return { ts, js: undefined };
+                }
+
+                const js = forEach(supportedJavascriptExtensions, tryExtension);
+                return js && { ts: undefined, js };
+            }
+        }
+
+        function tryExtension(ext: string): string | undefined {
+            return tryFile(candidate + ext, failedLookupLocations, onlyRecordFailures, state);
+        }
     }
 
     /** Return the file if it exists. */
@@ -619,9 +711,12 @@ namespace ts {
         }
     }
 
-    function loadNodeModuleFromDirectory(extensions: string[], candidate: string, failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string {
+    function loadNodeModuleFromDirectory(extensions: Extensions, candidate: string, failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
         const packageJsonPath = pathToPackageJson(candidate);
         const directoryExists = !onlyRecordFailures && directoryProbablyExists(candidate, state.host);
+
+        let fromPackageJson: Resolved | undefined;
+
         if (directoryExists && state.host.fileExists(packageJsonPath)) {
             if (state.traceEnabled) {
                 trace(state.host, Diagnostics.Found_package_json_at_0, packageJsonPath);
@@ -630,15 +725,18 @@ namespace ts {
             if (typesFile) {
                 const onlyRecordFailures = !directoryProbablyExists(getDirectoryPath(typesFile), state.host);
                 // A package.json "typings" may specify an exact filename, or may choose to omit an extension.
-                const result = tryFile(typesFile, failedLookupLocation, onlyRecordFailures, state) ||
-                    tryAddingExtensions(typesFile, extensions, failedLookupLocation, onlyRecordFailures, state);
-                if (result) {
-                    return result;
+                const fromFile = tryFile(typesFile, failedLookupLocation, onlyRecordFailures, state);
+                if (fromFile) {
+                    return resolvedFromAnyFile(fromFile);
+                }
+                fromPackageJson = tryAddingExtensions(typesFile, Extensions.All, failedLookupLocation, onlyRecordFailures, state);
+                if (fromPackageJson && fromPackageJson.ts) {
+                    return fromPackageJson;
                 }
             }
             else {
                 if (state.traceEnabled) {
-                    trace(state.host, Diagnostics.package_json_does_not_have_types_field);
+                    trace(state.host, Diagnostics.package_json_does_not_have_a_types_or_main_field);
                 }
             }
         }
@@ -650,58 +748,56 @@ namespace ts {
             failedLookupLocation.push(packageJsonPath);
         }
 
-        return loadModuleFromFile(combinePaths(candidate, "index"), extensions, failedLookupLocation, !directoryExists, state);
+        return combineAttempts(fromPackageJson, loadModuleFromFile(extensions, combinePaths(candidate, "index"), failedLookupLocation, !directoryExists, state));
     }
 
     function pathToPackageJson(directory: string): string {
         return combinePaths(directory, "package.json");
     }
 
-    function loadModuleFromNodeModulesFolder(moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState): string {
+    function loadModuleFromNodeModulesFolder(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
         const nodeModulesFolder = combinePaths(directory, "node_modules");
         const nodeModulesFolderExists = directoryProbablyExists(nodeModulesFolder, state.host);
         const candidate = normalizePath(combinePaths(nodeModulesFolder, moduleName));
-        const supportedExtensions = getSupportedExtensions(state.compilerOptions);
 
-        let result = loadModuleFromFile(candidate, supportedExtensions, failedLookupLocations, !nodeModulesFolderExists, state);
+        let result = loadModuleFromFile(extensions, candidate, failedLookupLocations, !nodeModulesFolderExists, state);
         if (result) {
             return result;
         }
-        result = loadNodeModuleFromDirectory(supportedExtensions, candidate, failedLookupLocations, !nodeModulesFolderExists, state);
+        result = loadNodeModuleFromDirectory(extensions, candidate, failedLookupLocations, !nodeModulesFolderExists, state);
         if (result) {
             return result;
         }
     }
 
-    /* @internal */
-    export function loadModuleFromNodeModules(moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState, checkOneLevel: boolean): string {
-        return loadModuleFromNodeModulesWorker(moduleName, directory, failedLookupLocations, state, checkOneLevel, /*typesOnly*/ false);
+    function loadModuleFromNodeModules(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState, checkOneLevel: boolean): Resolved | undefined {
+        return loadModuleFromNodeModulesWorker(extensions, moduleName, directory, failedLookupLocations, state, checkOneLevel, /*typesOnly*/ false);
     }
-
-    function loadModuleFromNodeModulesAtTypes(moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState): string {
-        return loadModuleFromNodeModulesWorker(moduleName, directory, failedLookupLocations, state, /*checkOneLevel*/ false, /*typesOnly*/ true);
+    function loadModuleFromNodeModulesAtTypes(moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
+        return loadModuleFromNodeModulesWorker(Extensions.All, moduleName, directory, failedLookupLocations, state, /*checkOneLevel*/ false, /*typesOnly*/ true);
     }
 
-    function loadModuleFromNodeModulesWorker(moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState, checkOneLevel: boolean, typesOnly: boolean): string {
+    function loadModuleFromNodeModulesWorker(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState, checkOneLevel: boolean, typesOnly: boolean): Resolved | undefined {
         directory = normalizeSlashes(directory);
         while (true) {
             const baseName = getBaseFileName(directory);
             if (baseName !== "node_modules") {
-                let packageResult: string | undefined;
+                let packageResult: Resolved | undefined;
                 if (!typesOnly) {
                     // Try to load source from the package
-                    packageResult = loadModuleFromNodeModulesFolder(moduleName, directory, failedLookupLocations, state);
-                    if (packageResult && hasTypeScriptFileExtension(packageResult)) {
+                    packageResult = loadModuleFromNodeModulesFolder(extensions, moduleName, directory, failedLookupLocations, state);
+                    if (packageResult && packageResult.ts) {
                         // Always prefer a TypeScript (.ts, .tsx, .d.ts) file shipped with the package
                         return packageResult;
                     }
                 }
 
                 // Else prefer a types package over non-TypeScript results (e.g. JavaScript files)
-                const typesResult = loadModuleFromNodeModulesFolder(combinePaths("@types", moduleName), directory, failedLookupLocations, state);
+                const typesResult = loadModuleFromNodeModulesFolder(extensions, combinePaths("@types", moduleName), directory, failedLookupLocations, state);
                 if (typesResult || packageResult) {
-                    return typesResult || packageResult;
+                    return combineAttempts(packageResult, typesResult);
                 }
+                // TODO (anhans): We should remember JS results and use them for untyped results.
             }
 
             const parentPath = getDirectoryPath(directory);
@@ -716,38 +812,34 @@ namespace ts {
 
     export function classicNameResolver(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost): ResolvedModuleWithFailedLookupLocations {
         const traceEnabled = isTraceEnabled(compilerOptions, host);
-        const state = { compilerOptions, host, traceEnabled, skipTsx: !compilerOptions.jsx };
+        const state: ModuleResolutionState = { compilerOptions, host, traceEnabled };
         const failedLookupLocations: string[] = [];
-        const supportedExtensions = getSupportedExtensions(compilerOptions);
         const containingDirectory = getDirectoryPath(containingFile);
 
-        const resolvedFileName = tryLoadModuleUsingOptionalResolutionSettings(moduleName, containingDirectory, loadModuleFromFile, failedLookupLocations, supportedExtensions, state);
-        if (resolvedFileName) {
-            return createResolvedModule(resolvedFileName, /*isExternalLibraryImport*/false, failedLookupLocations);
+        const resolvedUsingSettings = tryLoadModuleUsingOptionalResolutionSettings(moduleName, containingDirectory, loadModuleFromFileAnyExtension, failedLookupLocations, state);
+        if (resolvedUsingSettings) {
+            return createResolvedModuleWithFailedLookupLocations(resolvedUsingSettings, /*isExternalLibraryImport*/ false, failedLookupLocations);
         }
 
-        let referencedSourceFile: string;
+        let resolved: Resolved | undefined;
         if (moduleHasNonRelativeName(moduleName)) {
-            referencedSourceFile = referencedSourceFile = loadModuleFromAncestorDirectories(moduleName, containingDirectory, supportedExtensions, failedLookupLocations, state) ||
+            resolved = loadModuleFromAncestorDirectories(moduleName, containingDirectory, failedLookupLocations, state) ||
                 // If we didn't find the file normally, look it up in @types.
                 loadModuleFromNodeModulesAtTypes(moduleName, containingDirectory, failedLookupLocations, state);
         }
         else {
             const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
-            referencedSourceFile = loadModuleFromFile(candidate, supportedExtensions, failedLookupLocations, /*onlyRecordFailures*/ false, state);
+            resolved = loadModuleFromFileAnyExtension(candidate, failedLookupLocations, /*onlyRecordFailures*/ false, state);
         }
 
-
-        return referencedSourceFile
-            ? { resolvedModule: { resolvedFileName: referencedSourceFile }, failedLookupLocations }
-            : { resolvedModule: undefined, failedLookupLocations };
+        return createResolvedModuleWithFailedLookupLocations(resolved, /*isExternalLibraryImport*/ false, failedLookupLocations);
     }
 
     /** Climb up parent directories looking for a module. */
-    function loadModuleFromAncestorDirectories(moduleName: string, containingDirectory: string, supportedExtensions: string[], failedLookupLocations: string[], state: ModuleResolutionState): string | undefined {
+    function loadModuleFromAncestorDirectories(moduleName: string, containingDirectory: string, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
         while (true) {
             const searchName = normalizePath(combinePaths(containingDirectory, moduleName));
-            const referencedSourceFile = loadModuleFromFile(searchName, supportedExtensions, failedLookupLocations, /*onlyRecordFailures*/ false, state);
+            const referencedSourceFile = loadModuleFromFileAnyExtension(searchName, failedLookupLocations, /*onlyRecordFailures*/ false, state);
             if (referencedSourceFile) {
                 return referencedSourceFile;
             }
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 50e53ab9484b2..43bc877bc583a 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -307,7 +307,7 @@ namespace ts {
         // - This calls resolveModuleNames, and then calls findSourceFile for each resolved module.
         // As all these operations happen - and are nested - within the createProgram call, they close over the below variables.
         // The current resolution depth is tracked by incrementing/decrementing as the depth first search progresses.
-        const maxNodeModulesJsDepth = typeof options.maxNodeModuleJsDepth === "number" ? options.maxNodeModuleJsDepth : 0;
+        const maxNodeModuleJsDepth = typeof options.maxNodeModuleJsDepth === "number" ? options.maxNodeModuleJsDepth : 0;
         let currentNodeModulesDepth = 0;
 
         // If a module has some of its imports skipped due to being at the depth limit under node_modules, then track
@@ -331,7 +331,7 @@ namespace ts {
 
         let resolveModuleNamesWorker: (moduleNames: string[], containingFile: string) => ResolvedModule[];
         if (host.resolveModuleNames) {
-            resolveModuleNamesWorker = (moduleNames, containingFile) => host.resolveModuleNames(moduleNames, containingFile);
+            resolveModuleNamesWorker = (moduleNames, containingFile) => host.resolveModuleNames(moduleNames, containingFile).map(convertResolvedModuleFromHost);
         }
         else {
             const loader = (moduleName: string, containingFile: string) => resolveModuleName(moduleName, containingFile, options, host).resolvedModule;
@@ -1164,7 +1164,7 @@ namespace ts {
                 }
                 // See if we need to reprocess the imports due to prior skipped imports
                 else if (file && modulesWithElidedImports[file.path]) {
-                    if (currentNodeModulesDepth < maxNodeModulesJsDepth) {
+                    if (currentNodeModulesDepth < maxNodeModuleJsDepth) {
                         modulesWithElidedImports[file.path] = false;
                         processImportedModules(file, getDirectoryPath(fileName));
                     }
@@ -1308,35 +1308,40 @@ namespace ts {
                 file.resolvedModules = createMap<ResolvedModule>();
                 const moduleNames = map(concatenate(file.imports, file.moduleAugmentations), getTextOfLiteral);
                 const resolutions = resolveModuleNamesWorker(moduleNames, getNormalizedAbsolutePath(file.fileName, currentDirectory));
+                Debug.assert(resolutions.length === moduleNames.length);
                 for (let i = 0; i < moduleNames.length; i++) {
                     const resolution = resolutions[i];
                     setResolvedModule(file, moduleNames[i], resolution);
 
-                    // add file to program only if:
-                    // - resolution was successful
-                    // - noResolve is falsy
-                    // - module name comes from the list of imports
-                    // - it's not a top level JavaScript module that exceeded the search max
-                    const isFromNodeModulesSearch = resolution && resolution.isExternalLibraryImport;
-                    const isJsFileFromNodeModules = isFromNodeModulesSearch && hasJavaScriptFileExtension(resolution.resolvedFileName);
+                    if (!resolution) {
+                        continue;
+                    }
+
+                    const isFromNodeModulesSearch = resolution.isExternalLibraryImport;
+                    const isJsFileFromNodeModules = !resolution.resolvedTsFileName;
+                    const resolvedOrDiagnostic = getResolutionOrDiagnostic(options, resolution);
+                    // Ignore it if it has a bad extension (e.g. 'tsx' if we don't have '--allowJs') -- this will be reported by the checker, so just return undefined for now.
+                    const resolvedFileName = typeof resolvedOrDiagnostic === "string" ? resolvedOrDiagnostic : undefined;
 
                     if (isFromNodeModulesSearch) {
                         currentNodeModulesDepth++;
                     }
 
-                    const elideImport = isJsFileFromNodeModules && currentNodeModulesDepth > maxNodeModulesJsDepth;
-                    const shouldAddFile = resolution && !options.noResolve && i < file.imports.length && !elideImport;
+                    // add file to program only if:
+                    // - resolution was successful
+                    // - noResolve is falsy
+                    // - module name comes from the list of imports
+                    // - it's not a top level JavaScript module that exceeded the search max
+                    const elideImport = isJsFileFromNodeModules && currentNodeModulesDepth > maxNodeModuleJsDepth;
+                    const shouldAddFile = resolvedFileName && !options.noResolve && i < file.imports.length && !elideImport;
 
                     if (elideImport) {
                         modulesWithElidedImports[file.path] = true;
                     }
                     else if (shouldAddFile) {
-                        findSourceFile(resolution.resolvedFileName,
-                                toPath(resolution.resolvedFileName, currentDirectory, getCanonicalFileName),
-                                /*isDefaultLib*/ false, /*isReference*/ false,
-                                file,
-                                skipTrivia(file.text, file.imports[i].pos),
-                                file.imports[i].end);
+                        const path = toPath(resolvedFileName, currentDirectory, getCanonicalFileName);
+                        const pos = skipTrivia(file.text, file.imports[i].pos);
+                        findSourceFile(resolvedFileName, path, /*isDefaultLib*/ false, /*isReference*/ false, file, pos, file.imports[i].end);
                     }
 
                     if (isFromNodeModulesSearch) {
@@ -1348,7 +1353,6 @@ namespace ts {
                 // no imports - drop cached module resolutions
                 file.resolvedModules = undefined;
             }
-            return;
         }
 
         function computeCommonSourceDirectory(sourceFiles: SourceFile[]): string {
@@ -1573,4 +1577,27 @@ namespace ts {
             programDiagnostics.add(createCompilerDiagnostic(message, emitFileName));
         }
     }
+
+    /* @internal */
+    /**
+     * Extracts the file name from a ResolvedModule, or returns a DiagnosticMessage if we are not set up to use that kind of file.
+     * The DiagnosticMessage's parameters are the imported module name, and the filename it resolved to.
+     */
+    export function getResolutionOrDiagnostic(options: CompilerOptions, { resolvedTsFileName: ts, resolvedJsFileName: js }: ResolvedModule): string | { file: string, diag: DiagnosticMessage } {
+        if (ts) {
+            return !options.jsx && fileExtensionIs(ts, ".tsx")
+                ? { file: ts, diag: Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set }
+                : ts;
+        }
+        else {
+            if (!options.allowJs) {
+                return { file: js!, diag: Diagnostics.Module_0_was_resolved_to_1_but_allowJs_is_not_set };
+            }
+            else if (!options.jsx && fileExtensionIs(js!, ".jsx")) {
+                return { file: js!, diag: Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set };
+            }
+            else
+                return js!;
+        }
+    }
 }
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index dd1878f36a7f1..bc1a11febb14c 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -3287,19 +3287,42 @@ namespace ts {
         getDirectories?(path: string): string[];
     }
 
+    /**
+     * Represents the result of module resolution.
+     * Module resolution will pick up tsx/jsx/js files even if '--jsx' and '--allowJs' are turned off.
+     * The Program will then filter results based on these flags.
+     *
+     * At least one of `resolvedTsFileName` or `resolvedJsFileName` must be defined,
+     * else resolution should just return `undefined` instead of a ResolvedModule.
+     */
     export interface ResolvedModule {
+        /**
+         * This should always be set to `resolvedTsFileName || resolvedJsFileName`.
+         * Present for backwards compatibility.
+         */
         resolvedFileName: string;
-        /*
-         * Denotes if 'resolvedFileName' is isExternalLibraryImport and thus should be proper external module:
+        /** TypeScript (.d.ts, .ts, .tsx) file that the module was resolved to. This will be preferred over a JS file. */
+        resolvedTsFileName: string | undefined;
+        /** JavaScript (or .jsx) file that the module was resolved to. This should be returned even if '--allowJs' (or '--jsx') is disabled. */
+        resolvedJsFileName: string | undefined;
+        /**
+         * Denotes if 'resolvedFileName' is isExternalLibraryImport and thus should be a proper external module:
          * - be a .d.ts file
          * - use top level imports\exports
          * - don't use tripleslash references
          */
-        isExternalLibraryImport?: boolean;
+        isExternalLibraryImport: boolean;
     }
 
+    /**
+     * For backwards compatibility, a host may choose not to return `resolvedTsFileName` and `resolvedJsFileName` from a result ResolvedModule,
+     * in which case they will be inferred from the file extension.
+     * Prefer to return a full ResolvedModule.
+     */
+    export type ResolvedModuleFromHost = { resolvedFileName: string; isExternalLibraryImport: boolean } | ResolvedModule;
+
     export interface ResolvedModuleWithFailedLookupLocations {
-        resolvedModule: ResolvedModule;
+        resolvedModule: ResolvedModule | undefined;
         failedLookupLocations: string[];
     }
 
@@ -3335,7 +3358,7 @@ namespace ts {
          * If resolveModuleNames is implemented then implementation for members from ModuleResolutionHost can be just
          * 'throw new Error("NotImplemented")'
          */
-        resolveModuleNames?(moduleNames: string[], containingFile: string): ResolvedModule[];
+        resolveModuleNames?(moduleNames: string[], containingFile: string): ResolvedModuleFromHost[];
         /**
          * This method is a companion for 'resolveModuleNames' and is used to resolve 'types' references to actual type declaration files
          */
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 952a32052508e..bcb57d93ab6a9 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -118,6 +118,29 @@ namespace ts {
         sourceFile.resolvedModules[moduleNameText] = resolvedModule;
     }
 
+    /** Host may have omitted resolvedTsFileName and resolvedJsFileName, in which case we should infer them from the file extension of resolvedFileName. */
+    export function convertResolvedModuleFromHost(resolved: ResolvedModuleFromHost | undefined): ResolvedModule | undefined {
+        if (resolved === undefined) {
+            return undefined;
+        }
+        // `resolvedTsFileName` and `resolvedJsFileName` should be present as properties even if undefined.
+        else if ("resolvedTsFileName" in resolved) {
+            const { resolvedFileName, resolvedTsFileName, resolvedJsFileName } = resolved as ResolvedModule;
+            Debug.assert(resolvedFileName === (resolvedTsFileName || resolvedJsFileName));
+            return resolved as ResolvedModule;
+        }
+        else {
+            const { resolvedFileName, isExternalLibraryImport } = resolved;
+            if (fileExtensionIsAny(resolvedFileName, supportedTypeScriptExtensions)) {
+                return { resolvedFileName, resolvedTsFileName: resolvedFileName, resolvedJsFileName: undefined, isExternalLibraryImport };
+            }
+            else {
+                Debug.assert(fileExtensionIsAny(resolvedFileName, supportedJavascriptExtensions));
+                return { resolvedFileName, resolvedTsFileName: undefined, resolvedJsFileName: resolvedFileName, isExternalLibraryImport };
+            }
+        }
+    }
+
     export function setResolvedTypeReferenceDirective(sourceFile: SourceFile, typeReferenceDirectiveName: string, resolvedTypeReferenceDirective: ResolvedTypeReferenceDirective): void {
         if (!sourceFile.resolvedTypeReferenceDirectiveNames) {
             sourceFile.resolvedTypeReferenceDirectiveNames = createMap<ResolvedTypeReferenceDirective>();
@@ -127,8 +150,13 @@ namespace ts {
     }
 
     /* @internal */
+    /**
+     * Considers two ResolvedModules equal if they have the same `resolvedFileName`.
+     * Thus `{ ts: foo, js: bar }` is equal to `{ ts: foo, js: baz }` because `ts` is preferred.
+     */
     export function moduleResolutionIsEqualTo(oldResolution: ResolvedModule, newResolution: ResolvedModule): boolean {
-        return oldResolution.resolvedFileName === newResolution.resolvedFileName && oldResolution.isExternalLibraryImport === newResolution.isExternalLibraryImport;
+        return oldResolution.isExternalLibraryImport === newResolution.isExternalLibraryImport &&
+            oldResolution.resolvedFileName === newResolution.resolvedFileName;
     }
 
     /* @internal */
diff --git a/src/harness/unittests/moduleResolution.ts b/src/harness/unittests/moduleResolution.ts
index b2f7d0c224d3d..21e7f6f990d4c 100644
--- a/src/harness/unittests/moduleResolution.ts
+++ b/src/harness/unittests/moduleResolution.ts
@@ -1,6 +1,28 @@
 /// <reference path="..\harness.ts" />
 
 namespace ts {
+    export function checkResolvedModule(expected: ResolvedModule, actual: ResolvedModule): boolean {
+        if (!expected === !actual) {
+            if (expected) {
+                assert.isTrue(expected.resolvedTsFileName === actual.resolvedTsFileName, `'resolvedTsFileName': expected '${expected.resolvedTsFileName}' to be equal to '${actual.resolvedTsFileName}'`);
+                assert.isTrue(expected.resolvedJsFileName === actual.resolvedJsFileName, `'resolvedTsFileName': expected '${expected.resolvedJsFileName}' to be equal to '${actual.resolvedJsFileName}'`);
+                assert.isTrue(expected.isExternalLibraryImport === actual.isExternalLibraryImport, `'isExternalLibraryImport': expected '${expected.isExternalLibraryImport}' to be equal to '${actual.isExternalLibraryImport}'`);
+            }
+            return true;
+        }
+        return false;
+    }
+
+    export function checkResolvedModuleWithFailedLookupLocations(actual: ResolvedModuleWithFailedLookupLocations, expectedResolvedModule: ResolvedModule, expectedFailedLookupLocations: string[]): void {
+        assert.isTrue(actual.resolvedModule !== undefined, "module should be resolved");
+        checkResolvedModule(actual.resolvedModule, expectedResolvedModule);
+        assert.deepEqual(actual.failedLookupLocations, expectedFailedLookupLocations);
+    }
+
+    export function createTsResolvedModule(resolvedTsFileName: string, isExternalLibraryImport = false): ResolvedModule {
+        return { resolvedFileName: resolvedTsFileName, resolvedTsFileName, resolvedJsFileName: undefined, isExternalLibraryImport };
+    }
+
     interface File {
         name: string;
         content?: string;
@@ -53,8 +75,7 @@ namespace ts {
                 const containingFile = { name: containingFileName };
                 const moduleFile = { name: moduleFileNameNoExt + ext };
                 const resolution = nodeModuleNameResolver(moduleName, containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, moduleFile));
-                assert.equal(resolution.resolvedModule.resolvedFileName, moduleFile.name);
-                assert.equal(!!resolution.resolvedModule.isExternalLibraryImport, false);
+                checkResolvedModule(resolution.resolvedModule, createTsResolvedModule(moduleFile.name));
 
                 const failedLookupLocations: string[] = [];
                 const dir = getDirectoryPath(containingFileName);
@@ -97,10 +118,9 @@ namespace ts {
                 const packageJson = { name: packageJsonFileName, content: JSON.stringify({ "typings": fieldRef }) };
                 const moduleFile = { name: moduleFileName };
                 const resolution = nodeModuleNameResolver(moduleName, containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, packageJson, moduleFile));
-                assert.equal(resolution.resolvedModule.resolvedFileName, moduleFile.name);
-                assert.equal(!!resolution.resolvedModule.isExternalLibraryImport, false);
+                checkResolvedModule(resolution.resolvedModule, createTsResolvedModule(moduleFile.name));
                 // expect three failed lookup location - attempt to load module as file with all supported extensions
-                assert.equal(resolution.failedLookupLocations.length, supportedTypeScriptExtensions.length);
+                assert.equal(resolution.failedLookupLocations.length, allSupportedExtensions.length);
             }
         }
 
@@ -125,7 +145,7 @@ namespace ts {
 
                 const resolution = nodeModuleNameResolver("b", containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, packageJson, moduleFile, indexFile));
 
-                assert.equal(resolution.resolvedModule.resolvedFileName, indexPath);
+                checkResolvedModule(resolution.resolvedModule, createTsResolvedModule(indexPath, /*isExternalLibraryImport*/true));
             }
         }
 
@@ -138,7 +158,6 @@ namespace ts {
             /* tslint:enable no-null-keyword */
             testTypingsIgnored(undefined);
         });
-
         it("module name as directory - load index.d.ts", () => {
             test(/*hasDirectoryExists*/ false);
             test(/*hasDirectoryExists*/ true);
@@ -148,12 +167,18 @@ namespace ts {
                 const packageJson = { name: "/a/b/foo/package.json", content: JSON.stringify({ main: "/c/d" }) };
                 const indexFile = { name: "/a/b/foo/index.d.ts" };
                 const resolution = nodeModuleNameResolver("./foo", containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, packageJson, indexFile));
-                assert.equal(resolution.resolvedModule.resolvedFileName, indexFile.name);
-                assert.equal(!!resolution.resolvedModule.isExternalLibraryImport, false);
-                assert.deepEqual(resolution.failedLookupLocations, [
+                checkResolvedModuleWithFailedLookupLocations(resolution, createTsResolvedModule(indexFile.name), [
                     "/a/b/foo.ts",
                     "/a/b/foo.tsx",
                     "/a/b/foo.d.ts",
+                    "/a/b/foo.js",
+                    "/a/b/foo.jsx",
+                    "/c/d",
+                    "/c/d.ts",
+                    "/c/d.tsx",
+                    "/c/d.d.ts",
+                    "/c/d.js",
+                    "/c/d.jsx",
                     "/a/b/foo/index.ts",
                     "/a/b/foo/index.tsx",
                 ]);
@@ -170,36 +195,58 @@ namespace ts {
                 const containingFile = { name: "/a/b/c/d/e.ts" };
                 const moduleFile = { name: "/a/b/node_modules/foo.ts" };
                 const resolution = nodeModuleNameResolver("foo", containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, moduleFile));
-                assert.equal(resolution.resolvedModule.resolvedFileName, moduleFile.name);
-                assert.deepEqual(resolution.failedLookupLocations, [
+                checkResolvedModuleWithFailedLookupLocations(resolution, createTsResolvedModule(moduleFile.name, /*isExternalLibraryImport*/ true), [
                     "/a/b/c/d/node_modules/foo.ts",
                     "/a/b/c/d/node_modules/foo.tsx",
                     "/a/b/c/d/node_modules/foo.d.ts",
+                    "/a/b/c/d/node_modules/foo.js",
+                    "/a/b/c/d/node_modules/foo.jsx",
                     "/a/b/c/d/node_modules/foo/package.json",
+
                     "/a/b/c/d/node_modules/foo/index.ts",
                     "/a/b/c/d/node_modules/foo/index.tsx",
                     "/a/b/c/d/node_modules/foo/index.d.ts",
+                    "/a/b/c/d/node_modules/foo/index.js",
+                    "/a/b/c/d/node_modules/foo/index.jsx",
+
                     "/a/b/c/d/node_modules/@types/foo.ts",
                     "/a/b/c/d/node_modules/@types/foo.tsx",
                     "/a/b/c/d/node_modules/@types/foo.d.ts",
+                    "/a/b/c/d/node_modules/@types/foo.js",
+                    "/a/b/c/d/node_modules/@types/foo.jsx",
                     "/a/b/c/d/node_modules/@types/foo/package.json",
+
                     "/a/b/c/d/node_modules/@types/foo/index.ts",
                     "/a/b/c/d/node_modules/@types/foo/index.tsx",
                     "/a/b/c/d/node_modules/@types/foo/index.d.ts",
+                    "/a/b/c/d/node_modules/@types/foo/index.js",
+                    "/a/b/c/d/node_modules/@types/foo/index.jsx",
+
                     "/a/b/c/node_modules/foo.ts",
                     "/a/b/c/node_modules/foo.tsx",
                     "/a/b/c/node_modules/foo.d.ts",
+                    "/a/b/c/node_modules/foo.js",
+                    "/a/b/c/node_modules/foo.jsx",
                     "/a/b/c/node_modules/foo/package.json",
+
                     "/a/b/c/node_modules/foo/index.ts",
                     "/a/b/c/node_modules/foo/index.tsx",
                     "/a/b/c/node_modules/foo/index.d.ts",
+                    "/a/b/c/node_modules/foo/index.js",
+                    "/a/b/c/node_modules/foo/index.jsx",
+
                     "/a/b/c/node_modules/@types/foo.ts",
                     "/a/b/c/node_modules/@types/foo.tsx",
                     "/a/b/c/node_modules/@types/foo.d.ts",
+                    "/a/b/c/node_modules/@types/foo.js",
+                    "/a/b/c/node_modules/@types/foo.jsx",
                     "/a/b/c/node_modules/@types/foo/package.json",
+
                     "/a/b/c/node_modules/@types/foo/index.ts",
                     "/a/b/c/node_modules/@types/foo/index.tsx",
                     "/a/b/c/node_modules/@types/foo/index.d.ts",
+                    "/a/b/c/node_modules/@types/foo/index.js",
+                    "/a/b/c/node_modules/@types/foo/index.jsx",
                 ]);
             }
         });
@@ -212,8 +259,7 @@ namespace ts {
                 const containingFile = { name: "/a/b/c/d/e.ts" };
                 const moduleFile = { name: "/a/b/node_modules/foo.d.ts" };
                 const resolution = nodeModuleNameResolver("foo", containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, moduleFile));
-                assert.equal(resolution.resolvedModule.resolvedFileName, moduleFile.name);
-                assert.equal(resolution.resolvedModule.isExternalLibraryImport, true);
+                checkResolvedModule(resolution.resolvedModule, createTsResolvedModule(moduleFile.name, /*isExternalLibraryImport*/ true));
             }
         });
 
@@ -225,55 +271,92 @@ namespace ts {
                 const containingFile = { name: "/a/node_modules/b/c/node_modules/d/e.ts" };
                 const moduleFile = { name: "/a/node_modules/foo/index.d.ts" };
                 const resolution = nodeModuleNameResolver("foo", containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, moduleFile));
-                assert.equal(resolution.resolvedModule.resolvedFileName, moduleFile.name);
-                assert.equal(resolution.resolvedModule.isExternalLibraryImport, true);
-                assert.deepEqual(resolution.failedLookupLocations, [
+                checkResolvedModuleWithFailedLookupLocations(resolution, createTsResolvedModule(moduleFile.name, /*isExternalLibraryImport*/ true), [
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo.ts",
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo.tsx",
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo.d.ts",
+                    "/a/node_modules/b/c/node_modules/d/node_modules/foo.js",
+                    "/a/node_modules/b/c/node_modules/d/node_modules/foo.jsx",
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo/package.json",
+
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo/index.ts",
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo/index.tsx",
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo/index.d.ts",
+                    "/a/node_modules/b/c/node_modules/d/node_modules/foo/index.js",
+                    "/a/node_modules/b/c/node_modules/d/node_modules/foo/index.jsx",
+
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo.ts",
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo.tsx",
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo.d.ts",
+                    "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo.js",
+                    "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo.jsx",
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo/package.json",
+
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo/index.ts",
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo/index.tsx",
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo/index.d.ts",
+                    "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo/index.js",
+                    "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo/index.jsx",
+
                     "/a/node_modules/b/c/node_modules/foo.ts",
                     "/a/node_modules/b/c/node_modules/foo.tsx",
                     "/a/node_modules/b/c/node_modules/foo.d.ts",
+                    "/a/node_modules/b/c/node_modules/foo.js",
+                    "/a/node_modules/b/c/node_modules/foo.jsx",
                     "/a/node_modules/b/c/node_modules/foo/package.json",
+
                     "/a/node_modules/b/c/node_modules/foo/index.ts",
                     "/a/node_modules/b/c/node_modules/foo/index.tsx",
                     "/a/node_modules/b/c/node_modules/foo/index.d.ts",
+                    "/a/node_modules/b/c/node_modules/foo/index.js",
+                    "/a/node_modules/b/c/node_modules/foo/index.jsx",
+
                     "/a/node_modules/b/c/node_modules/@types/foo.ts",
                     "/a/node_modules/b/c/node_modules/@types/foo.tsx",
                     "/a/node_modules/b/c/node_modules/@types/foo.d.ts",
+                    "/a/node_modules/b/c/node_modules/@types/foo.js",
+                    "/a/node_modules/b/c/node_modules/@types/foo.jsx",
                     "/a/node_modules/b/c/node_modules/@types/foo/package.json",
+
                     "/a/node_modules/b/c/node_modules/@types/foo/index.ts",
                     "/a/node_modules/b/c/node_modules/@types/foo/index.tsx",
                     "/a/node_modules/b/c/node_modules/@types/foo/index.d.ts",
+                    "/a/node_modules/b/c/node_modules/@types/foo/index.js",
+                    "/a/node_modules/b/c/node_modules/@types/foo/index.jsx",
+
                     "/a/node_modules/b/node_modules/foo.ts",
                     "/a/node_modules/b/node_modules/foo.tsx",
                     "/a/node_modules/b/node_modules/foo.d.ts",
+                    "/a/node_modules/b/node_modules/foo.js",
+                    "/a/node_modules/b/node_modules/foo.jsx",
                     "/a/node_modules/b/node_modules/foo/package.json",
+
                     "/a/node_modules/b/node_modules/foo/index.ts",
                     "/a/node_modules/b/node_modules/foo/index.tsx",
                     "/a/node_modules/b/node_modules/foo/index.d.ts",
+                    "/a/node_modules/b/node_modules/foo/index.js",
+                    "/a/node_modules/b/node_modules/foo/index.jsx",
+
                     "/a/node_modules/b/node_modules/@types/foo.ts",
                     "/a/node_modules/b/node_modules/@types/foo.tsx",
                     "/a/node_modules/b/node_modules/@types/foo.d.ts",
+                    "/a/node_modules/b/node_modules/@types/foo.js",
+                    "/a/node_modules/b/node_modules/@types/foo.jsx",
                     "/a/node_modules/b/node_modules/@types/foo/package.json",
+
                     "/a/node_modules/b/node_modules/@types/foo/index.ts",
                     "/a/node_modules/b/node_modules/@types/foo/index.tsx",
                     "/a/node_modules/b/node_modules/@types/foo/index.d.ts",
+                    "/a/node_modules/b/node_modules/@types/foo/index.js",
+                    "/a/node_modules/b/node_modules/@types/foo/index.jsx",
+
                     "/a/node_modules/foo.ts",
                     "/a/node_modules/foo.tsx",
                     "/a/node_modules/foo.d.ts",
+                    "/a/node_modules/foo.js",
+                    "/a/node_modules/foo.jsx",
                     "/a/node_modules/foo/package.json",
+
                     "/a/node_modules/foo/index.ts",
                     "/a/node_modules/foo/index.tsx"
                 ]);
@@ -481,21 +564,15 @@ import b = require("./moduleB");
                     const options: CompilerOptions = { moduleResolution, baseUrl: "/root" };
                     {
                         const result = resolveModuleName("folder2/file2", file1.name, options, host);
-                        assert.isTrue(result.resolvedModule !== undefined, "module should be resolved");
-                        assert.equal(result.resolvedModule.resolvedFileName, file2.name);
-                        assert.deepEqual(result.failedLookupLocations, []);
+                        checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(file2.name), []);
                     }
                     {
                         const result = resolveModuleName("./file3", file2.name, options, host);
-                        assert.isTrue(result.resolvedModule !== undefined, "module should be resolved");
-                        assert.equal(result.resolvedModule.resolvedFileName, file3.name);
-                        assert.deepEqual(result.failedLookupLocations, []);
+                        checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(file3.name), []);
                     }
                     {
                         const result = resolveModuleName("/root/folder1/file1", file2.name, options, host);
-                        assert.isTrue(result.resolvedModule !== undefined, "module should be resolved");
-                        assert.equal(result.resolvedModule.resolvedFileName, file1.name);
-                        assert.deepEqual(result.failedLookupLocations, []);
+                        checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(file1.name), []);
                     }
                 }
             }
@@ -520,12 +597,11 @@ import b = require("./moduleB");
                 check("m1", main, m1);
                 check("m2", main, m2);
                 check("m3", main, m3Typings);
-                check("m4", main, m4);
+                check("m4", main, m4, /*isExternalLibraryImport*/true);
 
-                function check(name: string, caller: File, expected: File) {
+                function check(name: string, caller: File, expected: File, isExternalLibraryImport = false) {
                     const result = resolveModuleName(name, caller.name, options, host);
-                    assert.isTrue(result.resolvedModule !== undefined);
-                    assert.equal(result.resolvedModule.resolvedFileName, expected.name);
+                    checkResolvedModule(result.resolvedModule, createTsResolvedModule(expected.name, isExternalLibraryImport));
                 }
             }
         });
@@ -547,8 +623,7 @@ import b = require("./moduleB");
 
                 function check(name: string, caller: File, expected: File) {
                     const result = resolveModuleName(name, caller.name, options, host);
-                    assert.isTrue(result.resolvedModule !== undefined);
-                    assert.equal(result.resolvedModule.resolvedFileName, expected.name);
+                    checkResolvedModule(result.resolvedModule, createTsResolvedModule(expected.name));
                 }
             }
         });
@@ -589,10 +664,15 @@ import b = require("./moduleB");
                     "/root/folder1/file2.ts",
                     "/root/folder1/file2.tsx",
                     "/root/folder1/file2.d.ts",
+                    "/root/folder1/file2.js",
+                    "/root/folder1/file2.jsx",
                     "/root/folder1/file2/package.json",
+
                     "/root/folder1/file2/index.ts",
                     "/root/folder1/file2/index.tsx",
-                    "/root/folder1/file2/index.d.ts"
+                    "/root/folder1/file2/index.d.ts",
+                    "/root/folder1/file2/index.js",
+                    "/root/folder1/file2/index.jsx",
                     // then first attempt on 'generated/*' was successful
                 ]);
                 check("folder2/file3", file3, [
@@ -600,15 +680,24 @@ import b = require("./moduleB");
                     "/root/folder2/file3.ts",
                     "/root/folder2/file3.tsx",
                     "/root/folder2/file3.d.ts",
+                    "/root/folder2/file3.js",
+                    "/root/folder2/file3.jsx",
                     "/root/folder2/file3/package.json",
+
                     "/root/folder2/file3/index.ts",
                     "/root/folder2/file3/index.tsx",
                     "/root/folder2/file3/index.d.ts",
+                    "/root/folder2/file3/index.js",
+                    "/root/folder2/file3/index.jsx",
+
                     // then use remapped location
                     "/root/generated/folder2/file3.ts",
                     "/root/generated/folder2/file3.tsx",
                     "/root/generated/folder2/file3.d.ts",
+                    "/root/generated/folder2/file3.js",
+                    "/root/generated/folder2/file3.jsx",
                     "/root/generated/folder2/file3/package.json",
+
                     "/root/generated/folder2/file3/index.ts",
                     "/root/generated/folder2/file3/index.tsx",
                     // success on index.d.ts
@@ -618,14 +707,22 @@ import b = require("./moduleB");
                     "/root/folder2/file4.ts",
                     "/root/folder2/file4.tsx",
                     "/root/folder2/file4.d.ts",
+                    "/root/folder2/file4.js",
+                    "/root/folder2/file4.jsx",
                     "/root/folder2/file4/package.json",
+
                     "/root/folder2/file4/index.ts",
                     "/root/folder2/file4/index.tsx",
                     "/root/folder2/file4/index.d.ts",
+                    "/root/folder2/file4/index.js",
+                    "/root/folder2/file4/index.jsx",
+
                     // try to load from file from remapped location
                     "/root/generated/folder2/file4.ts",
                     "/root/generated/folder2/file4.tsx",
-                    "/root/generated/folder2/file4.d.ts"
+                    "/root/generated/folder2/file4.d.ts",
+                    "/root/generated/folder2/file4.js",
+                    "/root/generated/folder2/file4.jsx",
                     // success on loading as from folder
                 ]);
                 check("somefolder/file5", file5, [
@@ -634,6 +731,9 @@ import b = require("./moduleB");
                     "/root/someanotherfolder/file5.ts",
                     "/root/someanotherfolder/file5.tsx",
                     "/root/someanotherfolder/file5.d.ts",
+                    "/root/someanotherfolder/file5.js",
+                    "/root/someanotherfolder/file5.jsx",
+
                     // load from folder
                     "/root/someanotherfolder/file5/package.json",
                     "/root/someanotherfolder/file5/index.ts",
@@ -646,46 +746,67 @@ import b = require("./moduleB");
                     "/root/file6.ts",
                     "/root/file6.tsx",
                     "/root/file6.d.ts",
+                    "/root/file6.js",
+                    "/root/file6.jsx",
+
                     // load from folder
                     "/root/file6/package.json",
                     "/root/file6/index.ts",
                     "/root/file6/index.tsx",
                     "/root/file6/index.d.ts",
+                    "/root/file6/index.js",
+                    "/root/file6/index.jsx",
+
                     // then try 'generated/*'
                     // load from file
                     "/root/generated/file6.ts",
                     "/root/generated/file6.tsx",
                     "/root/generated/file6.d.ts",
+                    "/root/generated/file6.js",
+                    "/root/generated/file6.jsx",
+
                     // load from folder
                     "/root/generated/file6/package.json",
                     "/root/generated/file6/index.ts",
                     "/root/generated/file6/index.tsx",
                     "/root/generated/file6/index.d.ts",
+                    "/root/generated/file6/index.js",
+                    "/root/generated/file6/index.jsx",
+
                     // fallback to standard node behavior
                     // load from file
                     "/root/folder1/node_modules/file6.ts",
                     "/root/folder1/node_modules/file6.tsx",
                     "/root/folder1/node_modules/file6.d.ts",
+                    "/root/folder1/node_modules/file6.js",
+                    "/root/folder1/node_modules/file6.jsx",
+
                     // load from folder
                     "/root/folder1/node_modules/file6/package.json",
                     "/root/folder1/node_modules/file6/index.ts",
                     "/root/folder1/node_modules/file6/index.tsx",
                     "/root/folder1/node_modules/file6/index.d.ts",
+                    "/root/folder1/node_modules/file6/index.js",
+                    "/root/folder1/node_modules/file6/index.jsx",
+
                     "/root/folder1/node_modules/@types/file6.ts",
                     "/root/folder1/node_modules/@types/file6.tsx",
                     "/root/folder1/node_modules/@types/file6.d.ts",
+                    "/root/folder1/node_modules/@types/file6.js",
+                    "/root/folder1/node_modules/@types/file6.jsx",
+
                     "/root/folder1/node_modules/@types/file6/package.json",
                     "/root/folder1/node_modules/@types/file6/index.ts",
                     "/root/folder1/node_modules/@types/file6/index.tsx",
-                    "/root/folder1/node_modules/@types/file6/index.d.ts"
+                    "/root/folder1/node_modules/@types/file6/index.d.ts",
+                    "/root/folder1/node_modules/@types/file6/index.js",
+                    "/root/folder1/node_modules/@types/file6/index.jsx",
                     // success on /root/node_modules/file6.ts
-                ]);
+                ], /*isExternalLibraryImport*/ true);
 
-                function check(name: string, expected: File, expectedFailedLookups: string[]) {
+                function check(name: string, expected: File, expectedFailedLookups: string[], isExternalLibraryImport = false) {
                     const result = resolveModuleName(name, main.name, options, host);
-                    assert.isTrue(result.resolvedModule !== undefined, "module should be resolved");
-                    assert.equal(result.resolvedModule.resolvedFileName, expected.name);
-                    assert.deepEqual(result.failedLookupLocations, expectedFailedLookups);
+                    checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(expected.name, isExternalLibraryImport), expectedFailedLookups);
                 }
             }
         });
@@ -722,6 +843,8 @@ import b = require("./moduleB");
                     "/root/folder1/file2.ts",
                     "/root/folder1/file2.tsx",
                     "/root/folder1/file2.d.ts",
+                    "/root/folder1/file2.js",
+                    "/root/folder1/file2.jsx",
                     // success when using 'generated/*'
                 ]);
                 check("folder1/file3", file3, [
@@ -729,24 +852,30 @@ import b = require("./moduleB");
                     "/root/folder1/file3.ts",
                     "/root/folder1/file3.tsx",
                     "/root/folder1/file3.d.ts",
+                    "/root/folder1/file3.js",
+                    "/root/folder1/file3.jsx",
                     // then try 'generated/*'
                     "/root/generated/folder1/file3.ts",
                     "/root/generated/folder1/file3.tsx",
                     "/root/generated/folder1/file3.d.ts",
+                    "/root/generated/folder1/file3.js",
+                    "/root/generated/folder1/file3.jsx",
                     // fallback to classic
                     "/root/folder1/folder1/file3.ts",
                     "/root/folder1/folder1/file3.tsx",
                     "/root/folder1/folder1/file3.d.ts",
+                    "/root/folder1/folder1/file3.js",
+                    "/root/folder1/folder1/file3.jsx",
                     "/root/folder1/file3.ts",
                     "/root/folder1/file3.tsx",
                     "/root/folder1/file3.d.ts",
+                    "/root/folder1/file3.js",
+                    "/root/folder1/file3.jsx",
                 ]);
 
                 function check(name: string, expected: File, expectedFailedLookups: string[]) {
                     const result = resolveModuleName(name, main.name, options, host);
-                    assert.isTrue(result.resolvedModule !== undefined, "module should be resolved");
-                    assert.equal(result.resolvedModule.resolvedFileName, expected.name);
-                    assert.deepEqual(result.failedLookupLocations, expectedFailedLookups);
+                    checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(expected.name), expectedFailedLookups);
                 }
             }
         });
@@ -774,11 +903,15 @@ import b = require("./moduleB");
                     "/root/folder1/file2.ts",
                     "/root/folder1/file2.tsx",
                     "/root/folder1/file2.d.ts",
+                    "/root/folder1/file2.js",
+                    "/root/folder1/file2.jsx",
                     // load from folder
                     "/root/folder1/file2/package.json",
                     "/root/folder1/file2/index.ts",
                     "/root/folder1/file2/index.tsx",
                     "/root/folder1/file2/index.d.ts",
+                    "/root/folder1/file2/index.js",
+                    "/root/folder1/file2/index.jsx",
                     // success after using alternative rootDir entry
                 ]);
                 check("../folder1/file1", file3, file1, [
@@ -787,11 +920,15 @@ import b = require("./moduleB");
                     "/root/generated/folder1/file1.ts",
                     "/root/generated/folder1/file1.tsx",
                     "/root/generated/folder1/file1.d.ts",
+                    "/root/generated/folder1/file1.js",
+                    "/root/generated/folder1/file1.jsx",
                     // load from module
                     "/root/generated/folder1/file1/package.json",
                     "/root/generated/folder1/file1/index.ts",
                     "/root/generated/folder1/file1/index.tsx",
                     "/root/generated/folder1/file1/index.d.ts",
+                    "/root/generated/folder1/file1/index.js",
+                    "/root/generated/folder1/file1/index.jsx",
                     // success after using alternative rootDir entry
                 ]);
                 check("../folder1/file1_1", file3, file1_1, [
@@ -800,16 +937,22 @@ import b = require("./moduleB");
                     "/root/generated/folder1/file1_1.ts",
                     "/root/generated/folder1/file1_1.tsx",
                     "/root/generated/folder1/file1_1.d.ts",
+                    "/root/generated/folder1/file1_1.js",
+                    "/root/generated/folder1/file1_1.jsx",
                     // load from folder
                     "/root/generated/folder1/file1_1/package.json",
                     "/root/generated/folder1/file1_1/index.ts",
                     "/root/generated/folder1/file1_1/index.tsx",
                     "/root/generated/folder1/file1_1/index.d.ts",
+                    "/root/generated/folder1/file1_1/index.js",
+                    "/root/generated/folder1/file1_1/index.jsx",
                     // try alternative rootDir entry
                     // load from file
                     "/root/folder1/file1_1.ts",
                     "/root/folder1/file1_1.tsx",
                     "/root/folder1/file1_1.d.ts",
+                    "/root/folder1/file1_1.js",
+                    "/root/folder1/file1_1.jsx",
                     // load from directory
                     "/root/folder1/file1_1/package.json",
                     "/root/folder1/file1_1/index.ts",
@@ -819,9 +962,7 @@ import b = require("./moduleB");
 
                 function check(name: string, container: File, expected: File, expectedFailedLookups: string[]) {
                     const result = resolveModuleName(name, container.name, options, host);
-                    assert.isTrue(result.resolvedModule !== undefined, "module should be resolved");
-                    assert.equal(result.resolvedModule.resolvedFileName, expected.name);
-                    assert.deepEqual(result.failedLookupLocations, expectedFailedLookups);
+                    checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(expected.name), expectedFailedLookups);
                 }
             }
         });
@@ -848,6 +989,8 @@ import b = require("./moduleB");
                     "/root/folder1/file2.ts",
                     "/root/folder1/file2.tsx",
                     "/root/folder1/file2.d.ts",
+                    "/root/folder1/file2.js",
+                    "/root/folder1/file2.jsx",
                     // then try alternative rootDir entry
                 ]);
                 check("../folder1/file1", file3, file1, [
@@ -855,6 +998,8 @@ import b = require("./moduleB");
                     "/root/generated/folder1/file1.ts",
                     "/root/generated/folder1/file1.tsx",
                     "/root/generated/folder1/file1.d.ts",
+                    "/root/generated/folder1/file1.js",
+                    "/root/generated/folder1/file1.jsx",
                     // then try alternative rootDir entry
                 ]);
                 check("folder1/file1_1", file3, file4, [
@@ -862,22 +1007,26 @@ import b = require("./moduleB");
                     "/root/generated/folder2/folder1/file1_1.ts",
                     "/root/generated/folder2/folder1/file1_1.tsx",
                     "/root/generated/folder2/folder1/file1_1.d.ts",
+                    "/root/generated/folder2/folder1/file1_1.js",
+                    "/root/generated/folder2/folder1/file1_1.jsx",
                     // other entry in rootDirs
                     "/root/generated/folder1/file1_1.ts",
                     "/root/generated/folder1/file1_1.tsx",
                     "/root/generated/folder1/file1_1.d.ts",
+                    "/root/generated/folder1/file1_1.js",
+                    "/root/generated/folder1/file1_1.jsx",
                     // fallback
                     "/root/folder1/file1_1.ts",
                     "/root/folder1/file1_1.tsx",
                     "/root/folder1/file1_1.d.ts",
+                    "/root/folder1/file1_1.js",
+                    "/root/folder1/file1_1.jsx",
                     // found one
                 ]);
 
                 function check(name: string, container: File, expected: File, expectedFailedLookups: string[]) {
                     const result = resolveModuleName(name, container.name, options, host);
-                    assert.isTrue(result.resolvedModule !== undefined, "module should be resolved");
-                    assert.equal(result.resolvedModule.resolvedFileName, expected.name);
-                    assert.deepEqual(result.failedLookupLocations, expectedFailedLookups);
+                    checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(expected.name), expectedFailedLookups);
                 }
             }
         });
@@ -899,13 +1048,13 @@ import b = require("./moduleB");
                     }
                  };
                 const result = resolveModuleName("libs/guid", app.name, options, host);
-                assert.isTrue(result.resolvedModule !== undefined, "module should be resolved");
-                assert.equal(result.resolvedModule.resolvedFileName, libsTypings.name);
-                assert.deepEqual(result.failedLookupLocations, [
+                checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(libsTypings.name), [
                     // first try to load module as file
                     "/root/src/libs/guid.ts",
                     "/root/src/libs/guid.tsx",
                     "/root/src/libs/guid.d.ts",
+                    "/root/src/libs/guid.js",
+                    "/root/src/libs/guid.jsx",
                 ]);
             }
         });
diff --git a/src/harness/unittests/reuseProgramStructure.ts b/src/harness/unittests/reuseProgramStructure.ts
index 60687d34c55af..66b966aed16ff 100644
--- a/src/harness/unittests/reuseProgramStructure.ts
+++ b/src/harness/unittests/reuseProgramStructure.ts
@@ -152,17 +152,6 @@ namespace ts {
         return program;
     }
 
-    function checkResolvedModule(expected: ResolvedModule, actual: ResolvedModule): boolean {
-        if (!expected === !actual) {
-            if (expected) {
-                assert.isTrue(expected.resolvedFileName === actual.resolvedFileName, `'resolvedFileName': expected '${expected.resolvedFileName}' to be equal to '${actual.resolvedFileName}'`);
-                assert.isTrue(expected.isExternalLibraryImport === actual.isExternalLibraryImport, `'isExternalLibraryImport': expected '${expected.isExternalLibraryImport}' to be equal to '${actual.isExternalLibraryImport}'`);
-            }
-            return true;
-        }
-        return false;
-    }
-
     function checkResolvedTypeDirective(expected: ResolvedTypeReferenceDirective, actual: ResolvedTypeReferenceDirective): boolean {
         if (!expected === !actual) {
             if (expected) {
@@ -306,7 +295,7 @@ namespace ts {
             const options: CompilerOptions = { target };
 
             const program_1 = newProgram(files, ["a.ts"], options);
-            checkResolvedModulesCache(program_1, "a.ts", createMap({ "b": { resolvedFileName: "b.ts" } }));
+            checkResolvedModulesCache(program_1, "a.ts", createMap({ "b": createTsResolvedModule("b.ts") }));
             checkResolvedModulesCache(program_1, "b.ts", undefined);
 
             const program_2 = updateProgram(program_1, ["a.ts"], options, files => {
@@ -315,7 +304,7 @@ namespace ts {
             assert.isTrue(program_1.structureIsReused);
 
             // content of resolution cache should not change
-            checkResolvedModulesCache(program_1, "a.ts", createMap({ "b": { resolvedFileName: "b.ts" } }));
+            checkResolvedModulesCache(program_1, "a.ts", createMap({ "b": createTsResolvedModule("b.ts") }));
             checkResolvedModulesCache(program_1, "b.ts", undefined);
 
             // imports has changed - program is not reused
@@ -332,7 +321,7 @@ namespace ts {
                 files[0].text = files[0].text.updateImportsAndExports(newImports);
             });
             assert.isTrue(!program_3.structureIsReused);
-            checkResolvedModulesCache(program_4, "a.ts", createMap({ "b": { resolvedFileName: "b.ts" }, "c": undefined }));
+            checkResolvedModulesCache(program_4, "a.ts", createMap({ "b": createTsResolvedModule("b.ts"), "c": undefined }));
         });
 
         it("resolved type directives cache follows type directives", () => {
diff --git a/src/server/lsHost.ts b/src/server/lsHost.ts
index b36f73a19c545..d6dfb67ed04b7 100644
--- a/src/server/lsHost.ts
+++ b/src/server/lsHost.ts
@@ -5,8 +5,8 @@
 namespace ts.server {
     export class LSHost implements ts.LanguageServiceHost, ModuleResolutionHost, ServerLanguageServiceHost {
         private compilationSettings: ts.CompilerOptions;
-        private readonly resolvedModuleNames: ts.FileMap<Map<ResolvedModuleWithFailedLookupLocations>>;
-        private readonly resolvedTypeReferenceDirectives: ts.FileMap<Map<ResolvedTypeReferenceDirectiveWithFailedLookupLocations>>;
+        private readonly resolvedModuleNames= createFileMap<Map<ResolvedModuleWithFailedLookupLocations>>();
+        private readonly resolvedTypeReferenceDirectives = createFileMap<Map<ResolvedTypeReferenceDirectiveWithFailedLookupLocations>>();
         private readonly getCanonicalFileName: (fileName: string) => string;
 
         private readonly resolveModuleName: typeof resolveModuleName;
@@ -14,50 +14,26 @@ namespace ts.server {
 
         constructor(private readonly host: ServerHost, private readonly project: Project, private readonly cancellationToken: HostCancellationToken) {
             this.getCanonicalFileName = ts.createGetCanonicalFileName(this.host.useCaseSensitiveFileNames);
-            this.resolvedModuleNames = createFileMap<Map<ResolvedModuleWithFailedLookupLocations>>();
-            this.resolvedTypeReferenceDirectives = createFileMap<Map<ResolvedTypeReferenceDirectiveWithFailedLookupLocations>>();
 
             if (host.trace) {
                 this.trace = s => host.trace(s);
             }
 
             this.resolveModuleName = (moduleName, containingFile, compilerOptions, host) => {
-                const primaryResult = resolveModuleName(moduleName, containingFile, compilerOptions, host);
-                if (primaryResult.resolvedModule) {
-                    // return result immediately only if it is .ts, .tsx or .d.ts
-                    // otherwise try to load typings from @types
-                    if (fileExtensionIsAny(primaryResult.resolvedModule.resolvedFileName, supportedTypeScriptExtensions)) {
-                        return primaryResult;
-                    }
-                }
-                // create different collection of failed lookup locations for second pass
-                // if it will fail and we've already found something during the first pass - we don't want to pollute its results 
-                const secondaryLookupFailedLookupLocations: string[] = [];
-                const globalCache = this.project.projectService.typingsInstaller.globalTypingsCacheLocation;
-                if (this.project.getTypingOptions().enableAutoDiscovery && globalCache) {
-                    const traceEnabled = isTraceEnabled(compilerOptions, host);
-                    if (traceEnabled) {
-                        trace(host, Diagnostics.Auto_discovery_for_typings_is_enabled_in_project_0_Running_extra_resolution_pass_for_module_1_using_cache_location_2, this.project.getProjectName(), moduleName, globalCache);
-                    }
-                    const state: ModuleResolutionState = { compilerOptions, host, skipTsx: false, traceEnabled };
-                    const resolvedName = loadModuleFromNodeModules(moduleName, globalCache, secondaryLookupFailedLookupLocations, state, /*checkOneLevel*/ true);
-                    if (resolvedName) {
-                        return createResolvedModule(resolvedName, /*isExternalLibraryImport*/ true, primaryResult.failedLookupLocations.concat(secondaryLookupFailedLookupLocations));
-                    }
-                }
-                if (!primaryResult.resolvedModule && secondaryLookupFailedLookupLocations.length) {
-                    primaryResult.failedLookupLocations = primaryResult.failedLookupLocations.concat(secondaryLookupFailedLookupLocations);
-                }
-                return primaryResult;
+                const globalCache = this.project.getTypingOptions().enableAutoDiscovery
+                    ? this.project.projectService.typingsInstaller.globalTypingsCacheLocation
+                    : undefined;
+                return resolveModuleNameForLsHost(moduleName, containingFile, compilerOptions, host, globalCache, this.project.getProjectName());
             };
         }
 
-        private resolveNamesWithLocalCache<T extends { failedLookupLocations: string[] }, R extends { resolvedFileName?: string }>(
+        private resolveNamesWithLocalCache<T extends { failedLookupLocations: string[] }, R>(
             names: string[],
             containingFile: string,
             cache: ts.FileMap<Map<T>>,
             loader: (name: string, containingFile: string, options: CompilerOptions, host: ModuleResolutionHost) => T,
-            getResult: (s: T) => R): R[] {
+            getResult: (s: T) => R,
+            getResultFileName: (result: R) => string): R[] {
 
             const path = toPath(containingFile, this.host.getCurrentDirectory(), this.getCanonicalFileName);
             const currentResolutionsInFile = cache.get(path);
@@ -97,10 +73,7 @@ namespace ts.server {
 
                 const result = getResult(resolution);
                 if (result) {
-                    if (result.resolvedFileName && result.resolvedFileName === lastDeletedFileName) {
-                        return false;
-                    }
-                    return true;
+                    return getResultFileName(result) !== lastDeletedFileName;
                 }
 
                 // consider situation if we have no candidate locations as valid resolution.
@@ -126,11 +99,11 @@ namespace ts.server {
         }
 
         resolveTypeReferenceDirectives(typeDirectiveNames: string[], containingFile: string): ResolvedTypeReferenceDirective[] {
-            return this.resolveNamesWithLocalCache(typeDirectiveNames, containingFile, this.resolvedTypeReferenceDirectives, resolveTypeReferenceDirective, m => m.resolvedTypeReferenceDirective);
+            return this.resolveNamesWithLocalCache(typeDirectiveNames, containingFile, this.resolvedTypeReferenceDirectives, resolveTypeReferenceDirective, m => m.resolvedTypeReferenceDirective, r => r.resolvedFileName);
         }
 
         resolveModuleNames(moduleNames: string[], containingFile: string): ResolvedModule[] {
-            return this.resolveNamesWithLocalCache(moduleNames, containingFile, this.resolvedModuleNames, this.resolveModuleName, m => m.resolvedModule);
+            return this.resolveNamesWithLocalCache(moduleNames, containingFile, this.resolvedModuleNames, this.resolveModuleName, m => m.resolvedModule, r => r.resolvedFileName);
         }
 
         getDefaultLibFileName() {
diff --git a/src/server/typingsInstaller/typingsInstaller.ts b/src/server/typingsInstaller/typingsInstaller.ts
index f62f5fc4abe5c..546e4bf2c1194 100644
--- a/src/server/typingsInstaller/typingsInstaller.ts
+++ b/src/server/typingsInstaller/typingsInstaller.ts
@@ -35,7 +35,7 @@ namespace ts.server.typingsInstaller {
 
     export const MaxPackageNameLength = 214;
     /**
-     * Validates package name using rules defined at https://docs.npmjs.com/files/package.json 
+     * Validates package name using rules defined at https://docs.npmjs.com/files/package.json
      */
     export function validatePackageName(packageName: string): PackageNameValidationResult {
         Debug.assert(!!packageName, "Package name is not specified");
@@ -131,7 +131,7 @@ namespace ts.server.typingsInstaller {
                 this.log.writeLine(`Got install request ${JSON.stringify(req)}`);
             }
 
-            // load existing typing information from the cache 
+            // load existing typing information from the cache
             if (req.cachePath) {
                 if (this.log.isEnabled()) {
                     this.log.writeLine(`Request specifies cache path '${req.cachePath}', loading cached information...`);
diff --git a/src/services/shims.ts b/src/services/shims.ts
index 7ed1786640d7f..709aeb88496e5 100644
--- a/src/services/shims.ts
+++ b/src/services/shims.ts
@@ -328,7 +328,7 @@ namespace ts {
                     const resolutionsInFile = <MapLike<string>>JSON.parse(this.shimHost.getModuleResolutionsForFile(containingFile));
                     return map(moduleNames, name => {
                         const result = getProperty(resolutionsInFile, name);
-                        return result ? { resolvedFileName: result } : undefined;
+                        return result ? resolvedModuleFromAnyFile(result, /*isExternalLibraryImport*/ false) : undefined;
                     });
                 };
             }
diff --git a/tests/baselines/reference/importWithTrailingSlash_noResolve.trace.json b/tests/baselines/reference/importWithTrailingSlash_noResolve.trace.json
index e010603106f4c..db316e5db74cd 100644
--- a/tests/baselines/reference/importWithTrailingSlash_noResolve.trace.json
+++ b/tests/baselines/reference/importWithTrailingSlash_noResolve.trace.json
@@ -6,5 +6,7 @@
     "File '/foo/index.ts' does not exist.",
     "File '/foo/index.tsx' does not exist.",
     "File '/foo/index.d.ts' does not exist.",
+    "File '/foo/index.js' does not exist.",
+    "File '/foo/index.jsx' does not exist.",
     "======== Module name './foo/' was not resolved. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/library-reference-11.trace.json b/tests/baselines/reference/library-reference-11.trace.json
index e0af1e39c5ac8..6428f421d7e30 100644
--- a/tests/baselines/reference/library-reference-11.trace.json
+++ b/tests/baselines/reference/library-reference-11.trace.json
@@ -2,17 +2,12 @@
     "======== Resolving type reference directive 'jquery', containing file '/a/b/consumer.ts', root directory not set. ========",
     "Root directory cannot be determined, skipping primary search paths.",
     "Looking up in 'node_modules' folder, initial location '/a/b'",
-    "File '/a/b/node_modules/jquery.ts' does not exist.",
     "File '/a/b/node_modules/jquery.d.ts' does not exist.",
     "File '/a/b/node_modules/jquery/package.json' does not exist.",
-    "File '/a/b/node_modules/jquery/index.ts' does not exist.",
     "File '/a/b/node_modules/jquery/index.d.ts' does not exist.",
-    "File '/a/b/node_modules/@types/jquery.ts' does not exist.",
     "File '/a/b/node_modules/@types/jquery.d.ts' does not exist.",
     "File '/a/b/node_modules/@types/jquery/package.json' does not exist.",
-    "File '/a/b/node_modules/@types/jquery/index.ts' does not exist.",
     "File '/a/b/node_modules/@types/jquery/index.d.ts' does not exist.",
-    "File '/a/node_modules/jquery.ts' does not exist.",
     "File '/a/node_modules/jquery.d.ts' does not exist.",
     "Found 'package.json' at '/a/node_modules/jquery/package.json'.",
     "'package.json' has 'typings' field 'jquery.d.ts' that references '/a/node_modules/jquery/jquery.d.ts'.",
diff --git a/tests/baselines/reference/library-reference-12.trace.json b/tests/baselines/reference/library-reference-12.trace.json
index 2cdf1f5f20ace..37017c86f0c9e 100644
--- a/tests/baselines/reference/library-reference-12.trace.json
+++ b/tests/baselines/reference/library-reference-12.trace.json
@@ -2,17 +2,12 @@
     "======== Resolving type reference directive 'jquery', containing file '/a/b/consumer.ts', root directory not set. ========",
     "Root directory cannot be determined, skipping primary search paths.",
     "Looking up in 'node_modules' folder, initial location '/a/b'",
-    "File '/a/b/node_modules/jquery.ts' does not exist.",
     "File '/a/b/node_modules/jquery.d.ts' does not exist.",
     "File '/a/b/node_modules/jquery/package.json' does not exist.",
-    "File '/a/b/node_modules/jquery/index.ts' does not exist.",
     "File '/a/b/node_modules/jquery/index.d.ts' does not exist.",
-    "File '/a/b/node_modules/@types/jquery.ts' does not exist.",
     "File '/a/b/node_modules/@types/jquery.d.ts' does not exist.",
     "File '/a/b/node_modules/@types/jquery/package.json' does not exist.",
-    "File '/a/b/node_modules/@types/jquery/index.ts' does not exist.",
     "File '/a/b/node_modules/@types/jquery/index.d.ts' does not exist.",
-    "File '/a/node_modules/jquery.ts' does not exist.",
     "File '/a/node_modules/jquery.d.ts' does not exist.",
     "Found 'package.json' at '/a/node_modules/jquery/package.json'.",
     "'package.json' has 'types' field 'dist/jquery.d.ts' that references '/a/node_modules/jquery/dist/jquery.d.ts'.",
diff --git a/tests/baselines/reference/library-reference-3.trace.json b/tests/baselines/reference/library-reference-3.trace.json
index 419fe6d055d72..72cc8c950779b 100644
--- a/tests/baselines/reference/library-reference-3.trace.json
+++ b/tests/baselines/reference/library-reference-3.trace.json
@@ -2,10 +2,8 @@
     "======== Resolving type reference directive 'jquery', containing file '/src/consumer.ts', root directory not set. ========",
     "Root directory cannot be determined, skipping primary search paths.",
     "Looking up in 'node_modules' folder, initial location '/src'",
-    "File '/src/node_modules/jquery.ts' does not exist.",
     "File '/src/node_modules/jquery.d.ts' does not exist.",
     "File '/src/node_modules/jquery/package.json' does not exist.",
-    "File '/src/node_modules/jquery/index.ts' does not exist.",
     "File '/src/node_modules/jquery/index.d.ts' exist - use it as a name resolution result.",
     "======== Type reference directive 'jquery' was successfully resolved to '/src/node_modules/jquery/index.d.ts', primary: false. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/library-reference-4.trace.json b/tests/baselines/reference/library-reference-4.trace.json
index 5df7320d3223c..2a128b4fcbef4 100644
--- a/tests/baselines/reference/library-reference-4.trace.json
+++ b/tests/baselines/reference/library-reference-4.trace.json
@@ -4,20 +4,14 @@
     "File '/src/foo/package.json' does not exist.",
     "File '/src/foo/index.d.ts' does not exist.",
     "Looking up in 'node_modules' folder, initial location '/src'",
-    "File '/src/node_modules/foo.ts' does not exist.",
     "File '/src/node_modules/foo.d.ts' does not exist.",
     "File '/src/node_modules/foo/package.json' does not exist.",
-    "File '/src/node_modules/foo/index.ts' does not exist.",
     "File '/src/node_modules/foo/index.d.ts' does not exist.",
-    "File '/src/node_modules/@types/foo.ts' does not exist.",
     "File '/src/node_modules/@types/foo.d.ts' does not exist.",
     "File '/src/node_modules/@types/foo/package.json' does not exist.",
-    "File '/src/node_modules/@types/foo/index.ts' does not exist.",
     "File '/src/node_modules/@types/foo/index.d.ts' does not exist.",
-    "File '/node_modules/foo.ts' does not exist.",
     "File '/node_modules/foo.d.ts' does not exist.",
     "File '/node_modules/foo/package.json' does not exist.",
-    "File '/node_modules/foo/index.ts' does not exist.",
     "File '/node_modules/foo/index.d.ts' exist - use it as a name resolution result.",
     "======== Type reference directive 'foo' was successfully resolved to '/node_modules/foo/index.d.ts', primary: false. ========",
     "======== Resolving type reference directive 'bar', containing file '/src/root.ts', root directory '/src'. ========",
@@ -25,20 +19,14 @@
     "File '/src/bar/package.json' does not exist.",
     "File '/src/bar/index.d.ts' does not exist.",
     "Looking up in 'node_modules' folder, initial location '/src'",
-    "File '/src/node_modules/bar.ts' does not exist.",
     "File '/src/node_modules/bar.d.ts' does not exist.",
     "File '/src/node_modules/bar/package.json' does not exist.",
-    "File '/src/node_modules/bar/index.ts' does not exist.",
     "File '/src/node_modules/bar/index.d.ts' does not exist.",
-    "File '/src/node_modules/@types/bar.ts' does not exist.",
     "File '/src/node_modules/@types/bar.d.ts' does not exist.",
     "File '/src/node_modules/@types/bar/package.json' does not exist.",
-    "File '/src/node_modules/@types/bar/index.ts' does not exist.",
     "File '/src/node_modules/@types/bar/index.d.ts' does not exist.",
-    "File '/node_modules/bar.ts' does not exist.",
     "File '/node_modules/bar.d.ts' does not exist.",
     "File '/node_modules/bar/package.json' does not exist.",
-    "File '/node_modules/bar/index.ts' does not exist.",
     "File '/node_modules/bar/index.d.ts' exist - use it as a name resolution result.",
     "======== Type reference directive 'bar' was successfully resolved to '/node_modules/bar/index.d.ts', primary: false. ========",
     "======== Resolving type reference directive 'alpha', containing file '/node_modules/foo/index.d.ts', root directory '/src'. ========",
@@ -46,10 +34,8 @@
     "File '/src/alpha/package.json' does not exist.",
     "File '/src/alpha/index.d.ts' does not exist.",
     "Looking up in 'node_modules' folder, initial location '/node_modules/foo'",
-    "File '/node_modules/foo/node_modules/alpha.ts' does not exist.",
     "File '/node_modules/foo/node_modules/alpha.d.ts' does not exist.",
     "File '/node_modules/foo/node_modules/alpha/package.json' does not exist.",
-    "File '/node_modules/foo/node_modules/alpha/index.ts' does not exist.",
     "File '/node_modules/foo/node_modules/alpha/index.d.ts' exist - use it as a name resolution result.",
     "======== Type reference directive 'alpha' was successfully resolved to '/node_modules/foo/node_modules/alpha/index.d.ts', primary: false. ========",
     "======== Resolving type reference directive 'alpha', containing file '/node_modules/bar/index.d.ts', root directory '/src'. ========",
@@ -57,10 +43,8 @@
     "File '/src/alpha/package.json' does not exist.",
     "File '/src/alpha/index.d.ts' does not exist.",
     "Looking up in 'node_modules' folder, initial location '/node_modules/bar'",
-    "File '/node_modules/bar/node_modules/alpha.ts' does not exist.",
     "File '/node_modules/bar/node_modules/alpha.d.ts' does not exist.",
     "File '/node_modules/bar/node_modules/alpha/package.json' does not exist.",
-    "File '/node_modules/bar/node_modules/alpha/index.ts' does not exist.",
     "File '/node_modules/bar/node_modules/alpha/index.d.ts' exist - use it as a name resolution result.",
     "======== Type reference directive 'alpha' was successfully resolved to '/node_modules/bar/node_modules/alpha/index.d.ts', primary: false. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/library-reference-5.trace.json b/tests/baselines/reference/library-reference-5.trace.json
index 9b8705f032311..dc9bff30b274e 100644
--- a/tests/baselines/reference/library-reference-5.trace.json
+++ b/tests/baselines/reference/library-reference-5.trace.json
@@ -4,20 +4,14 @@
     "File 'types/foo/package.json' does not exist.",
     "File 'types/foo/index.d.ts' does not exist.",
     "Looking up in 'node_modules' folder, initial location '/src'",
-    "File '/src/node_modules/foo.ts' does not exist.",
     "File '/src/node_modules/foo.d.ts' does not exist.",
     "File '/src/node_modules/foo/package.json' does not exist.",
-    "File '/src/node_modules/foo/index.ts' does not exist.",
     "File '/src/node_modules/foo/index.d.ts' does not exist.",
-    "File '/src/node_modules/@types/foo.ts' does not exist.",
     "File '/src/node_modules/@types/foo.d.ts' does not exist.",
     "File '/src/node_modules/@types/foo/package.json' does not exist.",
-    "File '/src/node_modules/@types/foo/index.ts' does not exist.",
     "File '/src/node_modules/@types/foo/index.d.ts' does not exist.",
-    "File '/node_modules/foo.ts' does not exist.",
     "File '/node_modules/foo.d.ts' does not exist.",
     "File '/node_modules/foo/package.json' does not exist.",
-    "File '/node_modules/foo/index.ts' does not exist.",
     "File '/node_modules/foo/index.d.ts' exist - use it as a name resolution result.",
     "======== Type reference directive 'foo' was successfully resolved to '/node_modules/foo/index.d.ts', primary: false. ========",
     "======== Resolving type reference directive 'bar', containing file '/src/root.ts', root directory 'types'. ========",
@@ -25,20 +19,14 @@
     "File 'types/bar/package.json' does not exist.",
     "File 'types/bar/index.d.ts' does not exist.",
     "Looking up in 'node_modules' folder, initial location '/src'",
-    "File '/src/node_modules/bar.ts' does not exist.",
     "File '/src/node_modules/bar.d.ts' does not exist.",
     "File '/src/node_modules/bar/package.json' does not exist.",
-    "File '/src/node_modules/bar/index.ts' does not exist.",
     "File '/src/node_modules/bar/index.d.ts' does not exist.",
-    "File '/src/node_modules/@types/bar.ts' does not exist.",
     "File '/src/node_modules/@types/bar.d.ts' does not exist.",
     "File '/src/node_modules/@types/bar/package.json' does not exist.",
-    "File '/src/node_modules/@types/bar/index.ts' does not exist.",
     "File '/src/node_modules/@types/bar/index.d.ts' does not exist.",
-    "File '/node_modules/bar.ts' does not exist.",
     "File '/node_modules/bar.d.ts' does not exist.",
     "File '/node_modules/bar/package.json' does not exist.",
-    "File '/node_modules/bar/index.ts' does not exist.",
     "File '/node_modules/bar/index.d.ts' exist - use it as a name resolution result.",
     "======== Type reference directive 'bar' was successfully resolved to '/node_modules/bar/index.d.ts', primary: false. ========",
     "======== Resolving type reference directive 'alpha', containing file '/node_modules/foo/index.d.ts', root directory 'types'. ========",
@@ -46,10 +34,8 @@
     "File 'types/alpha/package.json' does not exist.",
     "File 'types/alpha/index.d.ts' does not exist.",
     "Looking up in 'node_modules' folder, initial location '/node_modules/foo'",
-    "File '/node_modules/foo/node_modules/alpha.ts' does not exist.",
     "File '/node_modules/foo/node_modules/alpha.d.ts' does not exist.",
     "File '/node_modules/foo/node_modules/alpha/package.json' does not exist.",
-    "File '/node_modules/foo/node_modules/alpha/index.ts' does not exist.",
     "File '/node_modules/foo/node_modules/alpha/index.d.ts' exist - use it as a name resolution result.",
     "======== Type reference directive 'alpha' was successfully resolved to '/node_modules/foo/node_modules/alpha/index.d.ts', primary: false. ========",
     "======== Resolving type reference directive 'alpha', containing file '/node_modules/bar/index.d.ts', root directory 'types'. ========",
@@ -57,10 +43,8 @@
     "File 'types/alpha/package.json' does not exist.",
     "File 'types/alpha/index.d.ts' does not exist.",
     "Looking up in 'node_modules' folder, initial location '/node_modules/bar'",
-    "File '/node_modules/bar/node_modules/alpha.ts' does not exist.",
     "File '/node_modules/bar/node_modules/alpha.d.ts' does not exist.",
     "File '/node_modules/bar/node_modules/alpha/package.json' does not exist.",
-    "File '/node_modules/bar/node_modules/alpha/index.ts' does not exist.",
     "File '/node_modules/bar/node_modules/alpha/index.d.ts' exist - use it as a name resolution result.",
     "======== Type reference directive 'alpha' was successfully resolved to '/node_modules/bar/node_modules/alpha/index.d.ts', primary: false. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/library-reference-7.trace.json b/tests/baselines/reference/library-reference-7.trace.json
index 419fe6d055d72..72cc8c950779b 100644
--- a/tests/baselines/reference/library-reference-7.trace.json
+++ b/tests/baselines/reference/library-reference-7.trace.json
@@ -2,10 +2,8 @@
     "======== Resolving type reference directive 'jquery', containing file '/src/consumer.ts', root directory not set. ========",
     "Root directory cannot be determined, skipping primary search paths.",
     "Looking up in 'node_modules' folder, initial location '/src'",
-    "File '/src/node_modules/jquery.ts' does not exist.",
     "File '/src/node_modules/jquery.d.ts' does not exist.",
     "File '/src/node_modules/jquery/package.json' does not exist.",
-    "File '/src/node_modules/jquery/index.ts' does not exist.",
     "File '/src/node_modules/jquery/index.d.ts' exist - use it as a name resolution result.",
     "======== Type reference directive 'jquery' was successfully resolved to '/src/node_modules/jquery/index.d.ts', primary: false. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionNoTs.js b/tests/baselines/reference/moduleResolutionNoTs.js
index 9ff33d688ea24..a17f108d87238 100644
--- a/tests/baselines/reference/moduleResolutionNoTs.js
+++ b/tests/baselines/reference/moduleResolutionNoTs.js
@@ -25,7 +25,7 @@ import z2 from "./z";
 "use strict";
 exports.__esModule = true;
 exports["default"] = 0;
-//// [y.js]
+//// [y.jsx]
 "use strict";
 exports.__esModule = true;
 exports["default"] = 0;
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions.trace.json
index 5060006ac56bd..924860326b891 100644
--- a/tests/baselines/reference/moduleResolutionWithExtensions.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithExtensions.trace.json
@@ -11,6 +11,8 @@
     "File '/src/a.js.ts' does not exist.",
     "File '/src/a.js.tsx' does not exist.",
     "File '/src/a.js.d.ts' does not exist.",
+    "File '/src/a.js.js' does not exist.",
+    "File '/src/a.js.jsx' does not exist.",
     "File name '/src/a.js' has a '.js' extension - stripping it",
     "File '/src/a.ts' exist - use it as a name resolution result.",
     "Resolving real path for '/src/a.ts', result '/src/a.ts'",
@@ -21,6 +23,8 @@
     "File '/src/jquery.js.ts' does not exist.",
     "File '/src/jquery.js.tsx' does not exist.",
     "File '/src/jquery.js.d.ts' does not exist.",
+    "File '/src/jquery.js.js' does not exist.",
+    "File '/src/jquery.js.jsx' does not exist.",
     "File name '/src/jquery.js' has a '.js' extension - stripping it",
     "File '/src/jquery.ts' does not exist.",
     "File '/src/jquery.tsx' does not exist.",
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.errors.txt b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.errors.txt
new file mode 100644
index 0000000000000..f1da7b7728dc2
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.errors.txt
@@ -0,0 +1,23 @@
+/a.ts(1,17): error TS6142: Module './tsx' was resolved to '/tsx.tsx', but '--jsx' is not set.
+/a.ts(2,17): error TS6143: Module './jsx' was resolved to '/jsx.jsx', but '--allowJs' is not set.
+/a.ts(3,16): error TS6143: Module './js' was resolved to '/js.js', but '--allowJs' is not set.
+
+
+==== /a.ts (3 errors) ====
+    import tsx from "./tsx";
+                    ~~~~~~~
+!!! error TS6142: Module './tsx' was resolved to '/tsx.tsx', but '--jsx' is not set.
+    import jsx from "./jsx";
+                    ~~~~~~~
+!!! error TS6143: Module './jsx' was resolved to '/jsx.jsx', but '--allowJs' is not set.
+    import js from "./js";
+                   ~~~~~~
+!!! error TS6143: Module './js' was resolved to '/js.js', but '--allowJs' is not set.
+    
+==== /tsx.tsx (0 errors) ====
+    
+    
+==== /jsx.jsx (0 errors) ====
+    
+==== /js.js (0 errors) ====
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.js b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.js
new file mode 100644
index 0000000000000..2e5297bdf65f8
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.js
@@ -0,0 +1,17 @@
+//// [tests/cases/compiler/moduleResolutionWithExtensions_notSupported.ts] ////
+
+//// [tsx.tsx]
+
+
+//// [jsx.jsx]
+
+//// [js.js]
+
+//// [a.ts]
+import tsx from "./tsx";
+import jsx from "./jsx";
+import js from "./js";
+
+
+//// [a.js]
+"use strict";
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.trace.json
new file mode 100644
index 0000000000000..5628c6fb7afc5
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.trace.json
@@ -0,0 +1,40 @@
+[
+    "======== Resolving module './tsx' from '/a.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module as file / folder, candidate module location '/tsx'.",
+    "File '/tsx.ts' does not exist.",
+    "File '/tsx.tsx' exist - use it as a name resolution result.",
+    "Resolving real path for '/tsx.tsx', result '/tsx.tsx'",
+    "======== Module name './tsx' was successfully resolved to '/tsx.tsx'. ========",
+    "======== Resolving module './jsx' from '/a.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module as file / folder, candidate module location '/jsx'.",
+    "File '/jsx.ts' does not exist.",
+    "File '/jsx.tsx' does not exist.",
+    "File '/jsx.d.ts' does not exist.",
+    "File '/jsx.js' does not exist.",
+    "File '/jsx.jsx' exist - use it as a name resolution result.",
+    "File '/jsx/package.json' does not exist.",
+    "File '/jsx/index.ts' does not exist.",
+    "File '/jsx/index.tsx' does not exist.",
+    "File '/jsx/index.d.ts' does not exist.",
+    "File '/jsx/index.js' does not exist.",
+    "File '/jsx/index.jsx' does not exist.",
+    "Resolving real path for '/jsx.jsx', result '/jsx.jsx'",
+    "======== Module name './jsx' was successfully resolved to '/jsx.jsx'. ========",
+    "======== Resolving module './js' from '/a.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module as file / folder, candidate module location '/js'.",
+    "File '/js.ts' does not exist.",
+    "File '/js.tsx' does not exist.",
+    "File '/js.d.ts' does not exist.",
+    "File '/js.js' exist - use it as a name resolution result.",
+    "File '/js/package.json' does not exist.",
+    "File '/js/index.ts' does not exist.",
+    "File '/js/index.tsx' does not exist.",
+    "File '/js/index.d.ts' does not exist.",
+    "File '/js/index.js' does not exist.",
+    "File '/js/index.jsx' does not exist.",
+    "Resolving real path for '/js.js', result '/js.js'",
+    "======== Module name './js' was successfully resolved to '/js.js'. ========"
+]
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.errors.txt b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.errors.txt
new file mode 100644
index 0000000000000..bb8a0664ed6ff
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.errors.txt
@@ -0,0 +1,12 @@
+/a.ts(1,17): error TS6142: Module './jsx' was resolved to '/jsx.jsx', but '--jsx' is not set.
+
+
+==== /a.ts (1 errors) ====
+    import jsx from "./jsx";
+                    ~~~~~~~
+!!! error TS6142: Module './jsx' was resolved to '/jsx.jsx', but '--jsx' is not set.
+    
+==== /jsx.jsx (0 errors) ====
+    // Test the error message if we have `--allowJs` but not `--jsx`.
+    
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.js b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.js
new file mode 100644
index 0000000000000..c340f65f251d7
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.js
@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/moduleResolutionWithExtensions_notSupported2.ts] ////
+
+//// [jsx.jsx]
+// Test the error message if we have `--allowJs` but not `--jsx`.
+
+
+//// [a.ts]
+import jsx from "./jsx";
+
+
+//// [a.js]
+"use strict";
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.trace.json
new file mode 100644
index 0000000000000..2d6170f9946b4
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.trace.json
@@ -0,0 +1,18 @@
+[
+    "======== Resolving module './jsx' from '/a.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module as file / folder, candidate module location '/jsx'.",
+    "File '/jsx.ts' does not exist.",
+    "File '/jsx.tsx' does not exist.",
+    "File '/jsx.d.ts' does not exist.",
+    "File '/jsx.js' does not exist.",
+    "File '/jsx.jsx' exist - use it as a name resolution result.",
+    "File '/jsx/package.json' does not exist.",
+    "File '/jsx/index.ts' does not exist.",
+    "File '/jsx/index.tsx' does not exist.",
+    "File '/jsx/index.d.ts' does not exist.",
+    "File '/jsx/index.js' does not exist.",
+    "File '/jsx/index.jsx' does not exist.",
+    "Resolving real path for '/jsx.jsx', result '/jsx.jsx'",
+    "======== Module name './jsx' was successfully resolved to '/jsx.jsx'. ========"
+]
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.js b/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.js
new file mode 100644
index 0000000000000..177321c7d0819
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.js
@@ -0,0 +1,18 @@
+//// [tests/cases/compiler/moduleResolutionWithExtensions_preferTs.ts] ////
+
+//// [b.js]
+
+
+//// [index.ts]
+export default 0;
+
+//// [a.ts]
+import b from "./b";
+
+
+//// [index.js]
+"use strict";
+exports.__esModule = true;
+exports["default"] = 0;
+//// [a.js]
+"use strict";
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.symbols b/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.symbols
new file mode 100644
index 0000000000000..af9dc4154d443
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.symbols
@@ -0,0 +1,8 @@
+=== /a.ts ===
+import b from "./b";
+>b : Symbol(b, Decl(a.ts, 0, 6))
+
+=== /b/index.ts ===
+export default 0;
+No type information for this code.
+No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.trace.json
new file mode 100644
index 0000000000000..150d492145c8c
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.trace.json
@@ -0,0 +1,14 @@
+[
+    "======== Resolving module './b' from '/a.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module as file / folder, candidate module location '/b'.",
+    "File '/b.ts' does not exist.",
+    "File '/b.tsx' does not exist.",
+    "File '/b.d.ts' does not exist.",
+    "File '/b.js' exist - use it as a name resolution result.",
+    "File '/b/package.json' does not exist.",
+    "File '/b/index.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/b/index.ts', result '/b/index.ts'",
+    "Resolving real path for '/b.js', result '/b.js'",
+    "======== Module name './b' was successfully resolved to '/b/index.ts'. ========"
+]
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.types b/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.types
new file mode 100644
index 0000000000000..0e418c5dc143c
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.types
@@ -0,0 +1,8 @@
+=== /a.ts ===
+import b from "./b";
+>b : 0
+
+=== /b/index.ts ===
+export default 0;
+No type information for this code.
+No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.js b/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.js
new file mode 100644
index 0000000000000..51d476338c024
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.js
@@ -0,0 +1,18 @@
+//// [tests/cases/compiler/moduleResolutionWithExtensions_withAmbientPresent.ts] ////
+
+//// [index.js]
+// Allowjs is false, but this should *not* warn about the unused 'index.js'
+
+
+//// [declarations.d.ts]
+declare module "js" {
+    export const x = 0;
+}
+
+//// [a.ts]
+/// <reference path="declarations.d.ts" />
+import { x } from "js";
+
+
+//// [a.js]
+"use strict";
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.symbols b/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.symbols
new file mode 100644
index 0000000000000..1259c83ccdea3
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.symbols
@@ -0,0 +1,11 @@
+=== /a.ts ===
+/// <reference path="declarations.d.ts" />
+import { x } from "js";
+>x : Symbol(x, Decl(a.ts, 1, 8))
+
+=== /declarations.d.ts ===
+declare module "js" {
+    export const x = 0;
+>x : Symbol(x, Decl(declarations.d.ts, 1, 16))
+}
+
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.trace.json
new file mode 100644
index 0000000000000..b2b46649529e2
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.trace.json
@@ -0,0 +1,28 @@
+[
+    "======== Resolving module 'js' from '/a.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module 'js' from 'node_modules' folder.",
+    "File '/node_modules/js.ts' does not exist.",
+    "File '/node_modules/js.tsx' does not exist.",
+    "File '/node_modules/js.d.ts' does not exist.",
+    "File '/node_modules/js.js' does not exist.",
+    "File '/node_modules/js.jsx' does not exist.",
+    "File '/node_modules/js/package.json' does not exist.",
+    "File '/node_modules/js/index.ts' does not exist.",
+    "File '/node_modules/js/index.tsx' does not exist.",
+    "File '/node_modules/js/index.d.ts' does not exist.",
+    "File '/node_modules/js/index.js' exist - use it as a name resolution result.",
+    "File '/node_modules/@types/js.ts' does not exist.",
+    "File '/node_modules/@types/js.tsx' does not exist.",
+    "File '/node_modules/@types/js.d.ts' does not exist.",
+    "File '/node_modules/@types/js.js' does not exist.",
+    "File '/node_modules/@types/js.jsx' does not exist.",
+    "File '/node_modules/@types/js/package.json' does not exist.",
+    "File '/node_modules/@types/js/index.ts' does not exist.",
+    "File '/node_modules/@types/js/index.tsx' does not exist.",
+    "File '/node_modules/@types/js/index.d.ts' does not exist.",
+    "File '/node_modules/@types/js/index.js' does not exist.",
+    "File '/node_modules/@types/js/index.jsx' does not exist.",
+    "Resolving real path for '/node_modules/js/index.js', result '/node_modules/js/index.js'",
+    "======== Module name 'js' was successfully resolved to '/node_modules/js/index.js'. ========"
+]
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.types b/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.types
new file mode 100644
index 0000000000000..1e5af4e7579ec
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.types
@@ -0,0 +1,12 @@
+=== /a.ts ===
+/// <reference path="declarations.d.ts" />
+import { x } from "js";
+>x : 0
+
+=== /declarations.d.ts ===
+declare module "js" {
+    export const x = 0;
+>x : 0
+>0 : 0
+}
+
diff --git a/tests/baselines/reference/moduleResolutionWithSymlinks.trace.json b/tests/baselines/reference/moduleResolutionWithSymlinks.trace.json
index f3bfae4b17346..d69fa7bfb50db 100644
--- a/tests/baselines/reference/moduleResolutionWithSymlinks.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithSymlinks.trace.json
@@ -5,6 +5,8 @@
     "File '/src/library-a.ts' does not exist.",
     "File '/src/library-a.tsx' does not exist.",
     "File '/src/library-a.d.ts' does not exist.",
+    "File '/src/library-a.js' does not exist.",
+    "File '/src/library-a.jsx' does not exist.",
     "File '/src/library-a/package.json' does not exist.",
     "File '/src/library-a/index.ts' exist - use it as a name resolution result.",
     "Resolving real path for '/src/library-a/index.ts', result '/src/library-a/index.ts'",
@@ -15,6 +17,8 @@
     "File '/src/library-b.ts' does not exist.",
     "File '/src/library-b.tsx' does not exist.",
     "File '/src/library-b.d.ts' does not exist.",
+    "File '/src/library-b.js' does not exist.",
+    "File '/src/library-b.jsx' does not exist.",
     "File '/src/library-b/package.json' does not exist.",
     "File '/src/library-b/index.ts' exist - use it as a name resolution result.",
     "Resolving real path for '/src/library-b/index.ts', result '/src/library-b/index.ts'",
@@ -25,44 +29,68 @@
     "File '/src/library-b/node_modules/library-a.ts' does not exist.",
     "File '/src/library-b/node_modules/library-a.tsx' does not exist.",
     "File '/src/library-b/node_modules/library-a.d.ts' does not exist.",
+    "File '/src/library-b/node_modules/library-a.js' does not exist.",
+    "File '/src/library-b/node_modules/library-a.jsx' does not exist.",
     "File '/src/library-b/node_modules/library-a/package.json' does not exist.",
     "File '/src/library-b/node_modules/library-a/index.ts' does not exist.",
     "File '/src/library-b/node_modules/library-a/index.tsx' does not exist.",
     "File '/src/library-b/node_modules/library-a/index.d.ts' does not exist.",
+    "File '/src/library-b/node_modules/library-a/index.js' does not exist.",
+    "File '/src/library-b/node_modules/library-a/index.jsx' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a.ts' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a.tsx' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a.d.ts' does not exist.",
+    "File '/src/library-b/node_modules/@types/library-a.js' does not exist.",
+    "File '/src/library-b/node_modules/@types/library-a.jsx' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a/package.json' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a/index.ts' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a/index.tsx' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a/index.d.ts' does not exist.",
+    "File '/src/library-b/node_modules/@types/library-a/index.js' does not exist.",
+    "File '/src/library-b/node_modules/@types/library-a/index.jsx' does not exist.",
     "File '/src/node_modules/library-a.ts' does not exist.",
     "File '/src/node_modules/library-a.tsx' does not exist.",
     "File '/src/node_modules/library-a.d.ts' does not exist.",
+    "File '/src/node_modules/library-a.js' does not exist.",
+    "File '/src/node_modules/library-a.jsx' does not exist.",
     "File '/src/node_modules/library-a/package.json' does not exist.",
     "File '/src/node_modules/library-a/index.ts' does not exist.",
     "File '/src/node_modules/library-a/index.tsx' does not exist.",
     "File '/src/node_modules/library-a/index.d.ts' does not exist.",
+    "File '/src/node_modules/library-a/index.js' does not exist.",
+    "File '/src/node_modules/library-a/index.jsx' does not exist.",
     "File '/src/node_modules/@types/library-a.ts' does not exist.",
     "File '/src/node_modules/@types/library-a.tsx' does not exist.",
     "File '/src/node_modules/@types/library-a.d.ts' does not exist.",
+    "File '/src/node_modules/@types/library-a.js' does not exist.",
+    "File '/src/node_modules/@types/library-a.jsx' does not exist.",
     "File '/src/node_modules/@types/library-a/package.json' does not exist.",
     "File '/src/node_modules/@types/library-a/index.ts' does not exist.",
     "File '/src/node_modules/@types/library-a/index.tsx' does not exist.",
     "File '/src/node_modules/@types/library-a/index.d.ts' does not exist.",
+    "File '/src/node_modules/@types/library-a/index.js' does not exist.",
+    "File '/src/node_modules/@types/library-a/index.jsx' does not exist.",
     "File '/node_modules/library-a.ts' does not exist.",
     "File '/node_modules/library-a.tsx' does not exist.",
     "File '/node_modules/library-a.d.ts' does not exist.",
+    "File '/node_modules/library-a.js' does not exist.",
+    "File '/node_modules/library-a.jsx' does not exist.",
     "File '/node_modules/library-a/package.json' does not exist.",
     "File '/node_modules/library-a/index.ts' does not exist.",
     "File '/node_modules/library-a/index.tsx' does not exist.",
     "File '/node_modules/library-a/index.d.ts' does not exist.",
+    "File '/node_modules/library-a/index.js' does not exist.",
+    "File '/node_modules/library-a/index.jsx' does not exist.",
     "File '/node_modules/@types/library-a.ts' does not exist.",
     "File '/node_modules/@types/library-a.tsx' does not exist.",
     "File '/node_modules/@types/library-a.d.ts' does not exist.",
+    "File '/node_modules/@types/library-a.js' does not exist.",
+    "File '/node_modules/@types/library-a.jsx' does not exist.",
     "File '/node_modules/@types/library-a/package.json' does not exist.",
     "File '/node_modules/@types/library-a/index.ts' does not exist.",
     "File '/node_modules/@types/library-a/index.tsx' does not exist.",
     "File '/node_modules/@types/library-a/index.d.ts' does not exist.",
+    "File '/node_modules/@types/library-a/index.js' does not exist.",
+    "File '/node_modules/@types/library-a/index.jsx' does not exist.",
     "======== Module name 'library-a' was not resolved. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution3_classic.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution3_classic.trace.json
index 8b003e05e8f04..22d93809b1bdd 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution3_classic.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution3_classic.trace.json
@@ -14,11 +14,20 @@
     "'baseUrl' option is set to 'c:/root', using this value to resolve non-relative module name 'file4'",
     "Resolving module name 'file4' relative to base url 'c:/root' - 'c:/root/file4'.",
     "File 'c:/root/file4.ts' does not exist.",
+    "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
+    "File 'c:/root/file4.js' does not exist.",
+    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/root/folder2/file4.ts' does not exist.",
+    "File 'c:/root/folder2/file4.tsx' does not exist.",
     "File 'c:/root/folder2/file4.d.ts' does not exist.",
+    "File 'c:/root/folder2/file4.js' does not exist.",
+    "File 'c:/root/folder2/file4.jsx' does not exist.",
     "File 'c:/root/file4.ts' does not exist.",
+    "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
+    "File 'c:/root/file4.js' does not exist.",
+    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/file4.ts' exist - use it as a name resolution result.",
     "======== Module name 'file4' was successfully resolved to 'c:/file4.ts'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution3_node.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution3_node.trace.json
index ab7210d7d020c..220f0f9c04b04 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution3_node.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution3_node.trace.json
@@ -21,42 +21,64 @@
     "File 'c:/root/file4.ts' does not exist.",
     "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
+    "File 'c:/root/file4.js' does not exist.",
+    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/root/file4/package.json' does not exist.",
     "File 'c:/root/file4/index.ts' does not exist.",
     "File 'c:/root/file4/index.tsx' does not exist.",
     "File 'c:/root/file4/index.d.ts' does not exist.",
+    "File 'c:/root/file4/index.js' does not exist.",
+    "File 'c:/root/file4/index.jsx' does not exist.",
     "Loading module 'file4' from 'node_modules' folder.",
     "File 'c:/root/folder2/node_modules/file4.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/file4.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/file4.d.ts' does not exist.",
+    "File 'c:/root/folder2/node_modules/file4.js' does not exist.",
+    "File 'c:/root/folder2/node_modules/file4.jsx' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/package.json' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/index.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/index.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/index.d.ts' does not exist.",
+    "File 'c:/root/folder2/node_modules/file4/index.js' does not exist.",
+    "File 'c:/root/folder2/node_modules/file4/index.jsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4.d.ts' does not exist.",
+    "File 'c:/root/folder2/node_modules/@types/file4.js' does not exist.",
+    "File 'c:/root/folder2/node_modules/@types/file4.jsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/package.json' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/index.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/index.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/index.d.ts' does not exist.",
+    "File 'c:/root/folder2/node_modules/@types/file4/index.js' does not exist.",
+    "File 'c:/root/folder2/node_modules/@types/file4/index.jsx' does not exist.",
     "File 'c:/root/node_modules/file4.ts' does not exist.",
     "File 'c:/root/node_modules/file4.tsx' does not exist.",
     "File 'c:/root/node_modules/file4.d.ts' does not exist.",
+    "File 'c:/root/node_modules/file4.js' does not exist.",
+    "File 'c:/root/node_modules/file4.jsx' does not exist.",
     "File 'c:/root/node_modules/file4/package.json' does not exist.",
     "File 'c:/root/node_modules/file4/index.ts' does not exist.",
     "File 'c:/root/node_modules/file4/index.tsx' does not exist.",
     "File 'c:/root/node_modules/file4/index.d.ts' does not exist.",
+    "File 'c:/root/node_modules/file4/index.js' does not exist.",
+    "File 'c:/root/node_modules/file4/index.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4.ts' does not exist.",
     "File 'c:/root/node_modules/@types/file4.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4.d.ts' does not exist.",
+    "File 'c:/root/node_modules/@types/file4.js' does not exist.",
+    "File 'c:/root/node_modules/@types/file4.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4/package.json' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.ts' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.d.ts' does not exist.",
+    "File 'c:/root/node_modules/@types/file4/index.js' does not exist.",
+    "File 'c:/root/node_modules/@types/file4/index.jsx' does not exist.",
     "File 'c:/node_modules/file4.ts' does not exist.",
     "File 'c:/node_modules/file4.tsx' does not exist.",
     "File 'c:/node_modules/file4.d.ts' does not exist.",
+    "File 'c:/node_modules/file4.js' does not exist.",
+    "File 'c:/node_modules/file4.jsx' does not exist.",
     "File 'c:/node_modules/file4/package.json' does not exist.",
     "File 'c:/node_modules/file4/index.ts' does not exist.",
     "File 'c:/node_modules/file4/index.tsx' does not exist.",
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution4_classic.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution4_classic.trace.json
index 8b003e05e8f04..22d93809b1bdd 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution4_classic.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution4_classic.trace.json
@@ -14,11 +14,20 @@
     "'baseUrl' option is set to 'c:/root', using this value to resolve non-relative module name 'file4'",
     "Resolving module name 'file4' relative to base url 'c:/root' - 'c:/root/file4'.",
     "File 'c:/root/file4.ts' does not exist.",
+    "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
+    "File 'c:/root/file4.js' does not exist.",
+    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/root/folder2/file4.ts' does not exist.",
+    "File 'c:/root/folder2/file4.tsx' does not exist.",
     "File 'c:/root/folder2/file4.d.ts' does not exist.",
+    "File 'c:/root/folder2/file4.js' does not exist.",
+    "File 'c:/root/folder2/file4.jsx' does not exist.",
     "File 'c:/root/file4.ts' does not exist.",
+    "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
+    "File 'c:/root/file4.js' does not exist.",
+    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/file4.ts' exist - use it as a name resolution result.",
     "======== Module name 'file4' was successfully resolved to 'c:/file4.ts'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution4_node.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution4_node.trace.json
index ab7210d7d020c..220f0f9c04b04 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution4_node.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution4_node.trace.json
@@ -21,42 +21,64 @@
     "File 'c:/root/file4.ts' does not exist.",
     "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
+    "File 'c:/root/file4.js' does not exist.",
+    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/root/file4/package.json' does not exist.",
     "File 'c:/root/file4/index.ts' does not exist.",
     "File 'c:/root/file4/index.tsx' does not exist.",
     "File 'c:/root/file4/index.d.ts' does not exist.",
+    "File 'c:/root/file4/index.js' does not exist.",
+    "File 'c:/root/file4/index.jsx' does not exist.",
     "Loading module 'file4' from 'node_modules' folder.",
     "File 'c:/root/folder2/node_modules/file4.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/file4.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/file4.d.ts' does not exist.",
+    "File 'c:/root/folder2/node_modules/file4.js' does not exist.",
+    "File 'c:/root/folder2/node_modules/file4.jsx' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/package.json' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/index.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/index.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/index.d.ts' does not exist.",
+    "File 'c:/root/folder2/node_modules/file4/index.js' does not exist.",
+    "File 'c:/root/folder2/node_modules/file4/index.jsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4.d.ts' does not exist.",
+    "File 'c:/root/folder2/node_modules/@types/file4.js' does not exist.",
+    "File 'c:/root/folder2/node_modules/@types/file4.jsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/package.json' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/index.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/index.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/index.d.ts' does not exist.",
+    "File 'c:/root/folder2/node_modules/@types/file4/index.js' does not exist.",
+    "File 'c:/root/folder2/node_modules/@types/file4/index.jsx' does not exist.",
     "File 'c:/root/node_modules/file4.ts' does not exist.",
     "File 'c:/root/node_modules/file4.tsx' does not exist.",
     "File 'c:/root/node_modules/file4.d.ts' does not exist.",
+    "File 'c:/root/node_modules/file4.js' does not exist.",
+    "File 'c:/root/node_modules/file4.jsx' does not exist.",
     "File 'c:/root/node_modules/file4/package.json' does not exist.",
     "File 'c:/root/node_modules/file4/index.ts' does not exist.",
     "File 'c:/root/node_modules/file4/index.tsx' does not exist.",
     "File 'c:/root/node_modules/file4/index.d.ts' does not exist.",
+    "File 'c:/root/node_modules/file4/index.js' does not exist.",
+    "File 'c:/root/node_modules/file4/index.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4.ts' does not exist.",
     "File 'c:/root/node_modules/@types/file4.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4.d.ts' does not exist.",
+    "File 'c:/root/node_modules/@types/file4.js' does not exist.",
+    "File 'c:/root/node_modules/@types/file4.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4/package.json' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.ts' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.d.ts' does not exist.",
+    "File 'c:/root/node_modules/@types/file4/index.js' does not exist.",
+    "File 'c:/root/node_modules/@types/file4/index.jsx' does not exist.",
     "File 'c:/node_modules/file4.ts' does not exist.",
     "File 'c:/node_modules/file4.tsx' does not exist.",
     "File 'c:/node_modules/file4.d.ts' does not exist.",
+    "File 'c:/node_modules/file4.js' does not exist.",
+    "File 'c:/node_modules/file4.jsx' does not exist.",
     "File 'c:/node_modules/file4/package.json' does not exist.",
     "File 'c:/node_modules/file4/index.ts' does not exist.",
     "File 'c:/node_modules/file4/index.tsx' does not exist.",
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution5_classic.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution5_classic.trace.json
index d1709c82dc676..8fd0dee8e747e 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution5_classic.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution5_classic.trace.json
@@ -14,7 +14,10 @@
     "Module name 'folder3/file2', matched pattern '*'.",
     "Trying substitution '*', candidate module location: 'folder3/file2'.",
     "File 'c:/root/folder3/file2.ts' does not exist.",
+    "File 'c:/root/folder3/file2.tsx' does not exist.",
     "File 'c:/root/folder3/file2.d.ts' does not exist.",
+    "File 'c:/root/folder3/file2.js' does not exist.",
+    "File 'c:/root/folder3/file2.jsx' does not exist.",
     "Trying substitution 'generated/*', candidate module location: 'generated/folder3/file2'.",
     "File 'c:/root/generated/folder3/file2.ts' exist - use it as a name resolution result.",
     "======== Module name 'folder3/file2' was successfully resolved to 'c:/root/generated/folder3/file2.ts'. ========",
@@ -33,14 +36,26 @@
     "Module name 'file4', matched pattern '*'.",
     "Trying substitution '*', candidate module location: 'file4'.",
     "File 'c:/root/file4.ts' does not exist.",
+    "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
+    "File 'c:/root/file4.js' does not exist.",
+    "File 'c:/root/file4.jsx' does not exist.",
     "Trying substitution 'generated/*', candidate module location: 'generated/file4'.",
     "File 'c:/root/generated/file4.ts' does not exist.",
+    "File 'c:/root/generated/file4.tsx' does not exist.",
     "File 'c:/root/generated/file4.d.ts' does not exist.",
+    "File 'c:/root/generated/file4.js' does not exist.",
+    "File 'c:/root/generated/file4.jsx' does not exist.",
     "File 'c:/root/folder1/file4.ts' does not exist.",
+    "File 'c:/root/folder1/file4.tsx' does not exist.",
     "File 'c:/root/folder1/file4.d.ts' does not exist.",
+    "File 'c:/root/folder1/file4.js' does not exist.",
+    "File 'c:/root/folder1/file4.jsx' does not exist.",
     "File 'c:/root/file4.ts' does not exist.",
+    "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
+    "File 'c:/root/file4.js' does not exist.",
+    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/file4.ts' exist - use it as a name resolution result.",
     "======== Module name 'file4' was successfully resolved to 'c:/file4.ts'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution5_node.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution5_node.trace.json
index 2efeefa24e5ca..8201ed793523e 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution5_node.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution5_node.trace.json
@@ -19,10 +19,14 @@
     "File 'c:/root/folder3/file2.ts' does not exist.",
     "File 'c:/root/folder3/file2.tsx' does not exist.",
     "File 'c:/root/folder3/file2.d.ts' does not exist.",
+    "File 'c:/root/folder3/file2.js' does not exist.",
+    "File 'c:/root/folder3/file2.jsx' does not exist.",
     "File 'c:/root/folder3/file2/package.json' does not exist.",
     "File 'c:/root/folder3/file2/index.ts' does not exist.",
     "File 'c:/root/folder3/file2/index.tsx' does not exist.",
     "File 'c:/root/folder3/file2/index.d.ts' does not exist.",
+    "File 'c:/root/folder3/file2/index.js' does not exist.",
+    "File 'c:/root/folder3/file2/index.jsx' does not exist.",
     "Trying substitution 'generated/*', candidate module location: 'generated/folder3/file2'.",
     "Loading module as file / folder, candidate module location 'c:/root/generated/folder3/file2'.",
     "File 'c:/root/generated/folder3/file2.ts' exist - use it as a name resolution result.",
@@ -38,6 +42,8 @@
     "File 'c:/root/shared/components/file3.ts' does not exist.",
     "File 'c:/root/shared/components/file3.tsx' does not exist.",
     "File 'c:/root/shared/components/file3.d.ts' does not exist.",
+    "File 'c:/root/shared/components/file3.js' does not exist.",
+    "File 'c:/root/shared/components/file3.jsx' does not exist.",
     "File 'c:/root/shared/components/file3/package.json' does not exist.",
     "File 'c:/root/shared/components/file3/index.ts' does not exist.",
     "File 'c:/root/shared/components/file3/index.tsx' does not exist.",
@@ -54,48 +60,72 @@
     "File 'c:/root/file4.ts' does not exist.",
     "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
+    "File 'c:/root/file4.js' does not exist.",
+    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/root/file4/package.json' does not exist.",
     "File 'c:/root/file4/index.ts' does not exist.",
     "File 'c:/root/file4/index.tsx' does not exist.",
     "File 'c:/root/file4/index.d.ts' does not exist.",
+    "File 'c:/root/file4/index.js' does not exist.",
+    "File 'c:/root/file4/index.jsx' does not exist.",
     "Trying substitution 'generated/*', candidate module location: 'generated/file4'.",
     "Loading module as file / folder, candidate module location 'c:/root/generated/file4'.",
     "File 'c:/root/generated/file4.ts' does not exist.",
     "File 'c:/root/generated/file4.tsx' does not exist.",
     "File 'c:/root/generated/file4.d.ts' does not exist.",
+    "File 'c:/root/generated/file4.js' does not exist.",
+    "File 'c:/root/generated/file4.jsx' does not exist.",
     "File 'c:/root/generated/file4/package.json' does not exist.",
     "File 'c:/root/generated/file4/index.ts' does not exist.",
     "File 'c:/root/generated/file4/index.tsx' does not exist.",
     "File 'c:/root/generated/file4/index.d.ts' does not exist.",
+    "File 'c:/root/generated/file4/index.js' does not exist.",
+    "File 'c:/root/generated/file4/index.jsx' does not exist.",
     "Loading module 'file4' from 'node_modules' folder.",
     "File 'c:/root/folder1/node_modules/file4.ts' does not exist.",
     "File 'c:/root/folder1/node_modules/file4.tsx' does not exist.",
     "File 'c:/root/folder1/node_modules/file4.d.ts' does not exist.",
+    "File 'c:/root/folder1/node_modules/file4.js' does not exist.",
+    "File 'c:/root/folder1/node_modules/file4.jsx' does not exist.",
     "File 'c:/root/folder1/node_modules/file4/package.json' does not exist.",
     "File 'c:/root/folder1/node_modules/file4/index.ts' does not exist.",
     "File 'c:/root/folder1/node_modules/file4/index.tsx' does not exist.",
     "File 'c:/root/folder1/node_modules/file4/index.d.ts' does not exist.",
+    "File 'c:/root/folder1/node_modules/file4/index.js' does not exist.",
+    "File 'c:/root/folder1/node_modules/file4/index.jsx' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4.ts' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4.tsx' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4.d.ts' does not exist.",
+    "File 'c:/root/folder1/node_modules/@types/file4.js' does not exist.",
+    "File 'c:/root/folder1/node_modules/@types/file4.jsx' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4/package.json' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4/index.ts' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4/index.tsx' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4/index.d.ts' does not exist.",
+    "File 'c:/root/folder1/node_modules/@types/file4/index.js' does not exist.",
+    "File 'c:/root/folder1/node_modules/@types/file4/index.jsx' does not exist.",
     "File 'c:/root/node_modules/file4.ts' does not exist.",
     "File 'c:/root/node_modules/file4.tsx' does not exist.",
     "File 'c:/root/node_modules/file4.d.ts' does not exist.",
+    "File 'c:/root/node_modules/file4.js' does not exist.",
+    "File 'c:/root/node_modules/file4.jsx' does not exist.",
     "File 'c:/root/node_modules/file4/package.json' does not exist.",
     "File 'c:/root/node_modules/file4/index.ts' does not exist.",
     "File 'c:/root/node_modules/file4/index.tsx' does not exist.",
     "File 'c:/root/node_modules/file4/index.d.ts' does not exist.",
+    "File 'c:/root/node_modules/file4/index.js' does not exist.",
+    "File 'c:/root/node_modules/file4/index.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4.ts' does not exist.",
     "File 'c:/root/node_modules/@types/file4.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4.d.ts' does not exist.",
+    "File 'c:/root/node_modules/@types/file4.js' does not exist.",
+    "File 'c:/root/node_modules/@types/file4.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4/package.json' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.ts' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.d.ts' does not exist.",
+    "File 'c:/root/node_modules/@types/file4/index.js' does not exist.",
+    "File 'c:/root/node_modules/@types/file4/index.jsx' does not exist.",
     "File 'c:/node_modules/file4.ts' exist - use it as a name resolution result.",
     "Resolving real path for 'c:/node_modules/file4.ts', result 'c:/node_modules/file4.ts'",
     "======== Module name 'file4' was successfully resolved to 'c:/node_modules/file4.ts'. ========"
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution6_classic.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution6_classic.trace.json
index 20fc416ccd479..d6c6b1a45bcc7 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution6_classic.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution6_classic.trace.json
@@ -7,7 +7,10 @@
     "Longest matching prefix for 'c:/root/src/project/file3' is 'c:/root/src/'",
     "Loading 'project/file3' from the root dir 'c:/root/src/', candidate location 'c:/root/src/project/file3'",
     "File 'c:/root/src/project/file3.ts' does not exist.",
+    "File 'c:/root/src/project/file3.tsx' does not exist.",
     "File 'c:/root/src/project/file3.d.ts' does not exist.",
+    "File 'c:/root/src/project/file3.js' does not exist.",
+    "File 'c:/root/src/project/file3.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'project/file3' from the root dir 'c:/root/generated/src', candidate location 'c:/root/generated/src/project/file3'",
     "File 'c:/root/generated/src/project/file3.ts' exist - use it as a name resolution result.",
@@ -20,10 +23,14 @@
     "Longest matching prefix for 'c:/root/generated/src/file2' is 'c:/root/generated/src/'",
     "Loading 'file2' from the root dir 'c:/root/generated/src/', candidate location 'c:/root/generated/src/file2'",
     "File 'c:/root/generated/src/file2.ts' does not exist.",
+    "File 'c:/root/generated/src/file2.tsx' does not exist.",
     "File 'c:/root/generated/src/file2.d.ts' does not exist.",
+    "File 'c:/root/generated/src/file2.js' does not exist.",
+    "File 'c:/root/generated/src/file2.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'file2' from the root dir 'c:/root/src', candidate location 'c:/root/src/file2'",
     "File 'c:/root/src/file2.ts' does not exist.",
+    "File 'c:/root/src/file2.tsx' does not exist.",
     "File 'c:/root/src/file2.d.ts' exist - use it as a name resolution result.",
     "======== Module name '../file2' was successfully resolved to 'c:/root/src/file2.d.ts'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution6_node.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution6_node.trace.json
index 28e51a119152d..92eb9ad072cb2 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution6_node.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution6_node.trace.json
@@ -10,10 +10,14 @@
     "File 'c:/root/src/project/file3.ts' does not exist.",
     "File 'c:/root/src/project/file3.tsx' does not exist.",
     "File 'c:/root/src/project/file3.d.ts' does not exist.",
+    "File 'c:/root/src/project/file3.js' does not exist.",
+    "File 'c:/root/src/project/file3.jsx' does not exist.",
     "File 'c:/root/src/project/file3/package.json' does not exist.",
     "File 'c:/root/src/project/file3/index.ts' does not exist.",
     "File 'c:/root/src/project/file3/index.tsx' does not exist.",
     "File 'c:/root/src/project/file3/index.d.ts' does not exist.",
+    "File 'c:/root/src/project/file3/index.js' does not exist.",
+    "File 'c:/root/src/project/file3/index.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'project/file3' from the root dir 'c:/root/generated/src', candidate location 'c:/root/generated/src/project/file3'",
     "Loading module as file / folder, candidate module location 'c:/root/generated/src/project/file3'.",
@@ -31,16 +35,22 @@
     "File 'c:/root/generated/src/file2.ts' does not exist.",
     "File 'c:/root/generated/src/file2.tsx' does not exist.",
     "File 'c:/root/generated/src/file2.d.ts' does not exist.",
+    "File 'c:/root/generated/src/file2.js' does not exist.",
+    "File 'c:/root/generated/src/file2.jsx' does not exist.",
     "File 'c:/root/generated/src/file2/package.json' does not exist.",
     "File 'c:/root/generated/src/file2/index.ts' does not exist.",
     "File 'c:/root/generated/src/file2/index.tsx' does not exist.",
     "File 'c:/root/generated/src/file2/index.d.ts' does not exist.",
+    "File 'c:/root/generated/src/file2/index.js' does not exist.",
+    "File 'c:/root/generated/src/file2/index.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'file2' from the root dir 'c:/root/src', candidate location 'c:/root/src/file2'",
     "Loading module as file / folder, candidate module location 'c:/root/src/file2'.",
     "File 'c:/root/src/file2.ts' does not exist.",
     "File 'c:/root/src/file2.tsx' does not exist.",
     "File 'c:/root/src/file2.d.ts' does not exist.",
+    "File 'c:/root/src/file2.js' does not exist.",
+    "File 'c:/root/src/file2.jsx' does not exist.",
     "File 'c:/root/src/file2/package.json' does not exist.",
     "File 'c:/root/src/file2/index.ts' does not exist.",
     "File 'c:/root/src/file2/index.tsx' does not exist.",
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution7_classic.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution7_classic.trace.json
index a8cadb8f0671a..24d43809bab14 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution7_classic.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution7_classic.trace.json
@@ -7,7 +7,10 @@
     "Longest matching prefix for 'c:/root/src/project/file2' is 'c:/root/src/'",
     "Loading 'project/file2' from the root dir 'c:/root/src/', candidate location 'c:/root/src/project/file2'",
     "File 'c:/root/src/project/file2.ts' does not exist.",
+    "File 'c:/root/src/project/file2.tsx' does not exist.",
     "File 'c:/root/src/project/file2.d.ts' does not exist.",
+    "File 'c:/root/src/project/file2.js' does not exist.",
+    "File 'c:/root/src/project/file2.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'project/file2' from the root dir 'c:/root/generated/src', candidate location 'c:/root/generated/src/project/file2'",
     "File 'c:/root/generated/src/project/file2.ts' exist - use it as a name resolution result.",
@@ -19,15 +22,28 @@
     "Module name 'module3', matched pattern '*'.",
     "Trying substitution '*', candidate module location: 'module3'.",
     "File 'c:/root/module3.ts' does not exist.",
+    "File 'c:/root/module3.tsx' does not exist.",
     "File 'c:/root/module3.d.ts' does not exist.",
+    "File 'c:/root/module3.js' does not exist.",
+    "File 'c:/root/module3.jsx' does not exist.",
     "Trying substitution 'c:/shared/*', candidate module location: 'c:/shared/module3'.",
     "File 'c:/shared/module3.ts' does not exist.",
+    "File 'c:/shared/module3.tsx' does not exist.",
     "File 'c:/shared/module3.d.ts' does not exist.",
+    "File 'c:/shared/module3.js' does not exist.",
+    "File 'c:/shared/module3.jsx' does not exist.",
     "File 'c:/root/src/module3.ts' does not exist.",
+    "File 'c:/root/src/module3.tsx' does not exist.",
     "File 'c:/root/src/module3.d.ts' does not exist.",
+    "File 'c:/root/src/module3.js' does not exist.",
+    "File 'c:/root/src/module3.jsx' does not exist.",
     "File 'c:/root/module3.ts' does not exist.",
+    "File 'c:/root/module3.tsx' does not exist.",
     "File 'c:/root/module3.d.ts' does not exist.",
+    "File 'c:/root/module3.js' does not exist.",
+    "File 'c:/root/module3.jsx' does not exist.",
     "File 'c:/module3.ts' does not exist.",
+    "File 'c:/module3.tsx' does not exist.",
     "File 'c:/module3.d.ts' exist - use it as a name resolution result.",
     "======== Module name 'module3' was successfully resolved to 'c:/module3.d.ts'. ========",
     "======== Resolving module 'module1' from 'c:/root/generated/src/project/file2.ts'. ========",
@@ -37,9 +53,13 @@
     "Module name 'module1', matched pattern '*'.",
     "Trying substitution '*', candidate module location: 'module1'.",
     "File 'c:/root/module1.ts' does not exist.",
+    "File 'c:/root/module1.tsx' does not exist.",
     "File 'c:/root/module1.d.ts' does not exist.",
+    "File 'c:/root/module1.js' does not exist.",
+    "File 'c:/root/module1.jsx' does not exist.",
     "Trying substitution 'c:/shared/*', candidate module location: 'c:/shared/module1'.",
     "File 'c:/shared/module1.ts' does not exist.",
+    "File 'c:/shared/module1.tsx' does not exist.",
     "File 'c:/shared/module1.d.ts' exist - use it as a name resolution result.",
     "======== Module name 'module1' was successfully resolved to 'c:/shared/module1.d.ts'. ========",
     "======== Resolving module 'templates/module2' from 'c:/root/generated/src/project/file2.ts'. ========",
@@ -58,10 +78,14 @@
     "Longest matching prefix for 'c:/root/generated/src/file3' is 'c:/root/generated/src/'",
     "Loading 'file3' from the root dir 'c:/root/generated/src/', candidate location 'c:/root/generated/src/file3'",
     "File 'c:/root/generated/src/file3.ts' does not exist.",
+    "File 'c:/root/generated/src/file3.tsx' does not exist.",
     "File 'c:/root/generated/src/file3.d.ts' does not exist.",
+    "File 'c:/root/generated/src/file3.js' does not exist.",
+    "File 'c:/root/generated/src/file3.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'file3' from the root dir 'c:/root/src', candidate location 'c:/root/src/file3'",
     "File 'c:/root/src/file3.ts' does not exist.",
+    "File 'c:/root/src/file3.tsx' does not exist.",
     "File 'c:/root/src/file3.d.ts' exist - use it as a name resolution result.",
     "======== Module name '../file3' was successfully resolved to 'c:/root/src/file3.d.ts'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution7_node.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution7_node.trace.json
index 48633c85e3b48..003f56463fb05 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution7_node.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution7_node.trace.json
@@ -10,10 +10,14 @@
     "File 'c:/root/src/project/file2.ts' does not exist.",
     "File 'c:/root/src/project/file2.tsx' does not exist.",
     "File 'c:/root/src/project/file2.d.ts' does not exist.",
+    "File 'c:/root/src/project/file2.js' does not exist.",
+    "File 'c:/root/src/project/file2.jsx' does not exist.",
     "File 'c:/root/src/project/file2/package.json' does not exist.",
     "File 'c:/root/src/project/file2/index.ts' does not exist.",
     "File 'c:/root/src/project/file2/index.tsx' does not exist.",
     "File 'c:/root/src/project/file2/index.d.ts' does not exist.",
+    "File 'c:/root/src/project/file2/index.js' does not exist.",
+    "File 'c:/root/src/project/file2/index.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'project/file2' from the root dir 'c:/root/generated/src', candidate location 'c:/root/generated/src/project/file2'",
     "Loading module as file / folder, candidate module location 'c:/root/generated/src/project/file2'.",
@@ -30,48 +34,72 @@
     "File 'c:/root/module3.ts' does not exist.",
     "File 'c:/root/module3.tsx' does not exist.",
     "File 'c:/root/module3.d.ts' does not exist.",
+    "File 'c:/root/module3.js' does not exist.",
+    "File 'c:/root/module3.jsx' does not exist.",
     "File 'c:/root/module3/package.json' does not exist.",
     "File 'c:/root/module3/index.ts' does not exist.",
     "File 'c:/root/module3/index.tsx' does not exist.",
     "File 'c:/root/module3/index.d.ts' does not exist.",
+    "File 'c:/root/module3/index.js' does not exist.",
+    "File 'c:/root/module3/index.jsx' does not exist.",
     "Trying substitution 'c:/shared/*', candidate module location: 'c:/shared/module3'.",
     "Loading module as file / folder, candidate module location 'c:/shared/module3'.",
     "File 'c:/shared/module3.ts' does not exist.",
     "File 'c:/shared/module3.tsx' does not exist.",
     "File 'c:/shared/module3.d.ts' does not exist.",
+    "File 'c:/shared/module3.js' does not exist.",
+    "File 'c:/shared/module3.jsx' does not exist.",
     "File 'c:/shared/module3/package.json' does not exist.",
     "File 'c:/shared/module3/index.ts' does not exist.",
     "File 'c:/shared/module3/index.tsx' does not exist.",
     "File 'c:/shared/module3/index.d.ts' does not exist.",
+    "File 'c:/shared/module3/index.js' does not exist.",
+    "File 'c:/shared/module3/index.jsx' does not exist.",
     "Loading module 'module3' from 'node_modules' folder.",
     "File 'c:/root/src/node_modules/module3.ts' does not exist.",
     "File 'c:/root/src/node_modules/module3.tsx' does not exist.",
     "File 'c:/root/src/node_modules/module3.d.ts' does not exist.",
+    "File 'c:/root/src/node_modules/module3.js' does not exist.",
+    "File 'c:/root/src/node_modules/module3.jsx' does not exist.",
     "File 'c:/root/src/node_modules/module3/package.json' does not exist.",
     "File 'c:/root/src/node_modules/module3/index.ts' does not exist.",
     "File 'c:/root/src/node_modules/module3/index.tsx' does not exist.",
     "File 'c:/root/src/node_modules/module3/index.d.ts' does not exist.",
+    "File 'c:/root/src/node_modules/module3/index.js' does not exist.",
+    "File 'c:/root/src/node_modules/module3/index.jsx' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3.ts' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3.tsx' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3.d.ts' does not exist.",
+    "File 'c:/root/src/node_modules/@types/module3.js' does not exist.",
+    "File 'c:/root/src/node_modules/@types/module3.jsx' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3/package.json' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3/index.ts' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3/index.tsx' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3/index.d.ts' does not exist.",
+    "File 'c:/root/src/node_modules/@types/module3/index.js' does not exist.",
+    "File 'c:/root/src/node_modules/@types/module3/index.jsx' does not exist.",
     "File 'c:/root/node_modules/module3.ts' does not exist.",
     "File 'c:/root/node_modules/module3.tsx' does not exist.",
     "File 'c:/root/node_modules/module3.d.ts' does not exist.",
+    "File 'c:/root/node_modules/module3.js' does not exist.",
+    "File 'c:/root/node_modules/module3.jsx' does not exist.",
     "File 'c:/root/node_modules/module3/package.json' does not exist.",
     "File 'c:/root/node_modules/module3/index.ts' does not exist.",
     "File 'c:/root/node_modules/module3/index.tsx' does not exist.",
     "File 'c:/root/node_modules/module3/index.d.ts' does not exist.",
+    "File 'c:/root/node_modules/module3/index.js' does not exist.",
+    "File 'c:/root/node_modules/module3/index.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/module3.ts' does not exist.",
     "File 'c:/root/node_modules/@types/module3.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/module3.d.ts' does not exist.",
+    "File 'c:/root/node_modules/@types/module3.js' does not exist.",
+    "File 'c:/root/node_modules/@types/module3.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/module3/package.json' does not exist.",
     "File 'c:/root/node_modules/@types/module3/index.ts' does not exist.",
     "File 'c:/root/node_modules/@types/module3/index.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/module3/index.d.ts' does not exist.",
+    "File 'c:/root/node_modules/@types/module3/index.js' does not exist.",
+    "File 'c:/root/node_modules/@types/module3/index.jsx' does not exist.",
     "File 'c:/node_modules/module3.ts' does not exist.",
     "File 'c:/node_modules/module3.tsx' does not exist.",
     "File 'c:/node_modules/module3.d.ts' exist - use it as a name resolution result.",
@@ -87,15 +115,21 @@
     "File 'c:/root/module1.ts' does not exist.",
     "File 'c:/root/module1.tsx' does not exist.",
     "File 'c:/root/module1.d.ts' does not exist.",
+    "File 'c:/root/module1.js' does not exist.",
+    "File 'c:/root/module1.jsx' does not exist.",
     "File 'c:/root/module1/package.json' does not exist.",
     "File 'c:/root/module1/index.ts' does not exist.",
     "File 'c:/root/module1/index.tsx' does not exist.",
     "File 'c:/root/module1/index.d.ts' does not exist.",
+    "File 'c:/root/module1/index.js' does not exist.",
+    "File 'c:/root/module1/index.jsx' does not exist.",
     "Trying substitution 'c:/shared/*', candidate module location: 'c:/shared/module1'.",
     "Loading module as file / folder, candidate module location 'c:/shared/module1'.",
     "File 'c:/shared/module1.ts' does not exist.",
     "File 'c:/shared/module1.tsx' does not exist.",
     "File 'c:/shared/module1.d.ts' does not exist.",
+    "File 'c:/shared/module1.js' does not exist.",
+    "File 'c:/shared/module1.jsx' does not exist.",
     "File 'c:/shared/module1/package.json' does not exist.",
     "File 'c:/shared/module1/index.ts' does not exist.",
     "File 'c:/shared/module1/index.tsx' does not exist.",
@@ -123,16 +157,22 @@
     "File 'c:/root/generated/src/file3.ts' does not exist.",
     "File 'c:/root/generated/src/file3.tsx' does not exist.",
     "File 'c:/root/generated/src/file3.d.ts' does not exist.",
+    "File 'c:/root/generated/src/file3.js' does not exist.",
+    "File 'c:/root/generated/src/file3.jsx' does not exist.",
     "File 'c:/root/generated/src/file3/package.json' does not exist.",
     "File 'c:/root/generated/src/file3/index.ts' does not exist.",
     "File 'c:/root/generated/src/file3/index.tsx' does not exist.",
     "File 'c:/root/generated/src/file3/index.d.ts' does not exist.",
+    "File 'c:/root/generated/src/file3/index.js' does not exist.",
+    "File 'c:/root/generated/src/file3/index.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'file3' from the root dir 'c:/root/src', candidate location 'c:/root/src/file3'",
     "Loading module as file / folder, candidate module location 'c:/root/src/file3'.",
     "File 'c:/root/src/file3.ts' does not exist.",
     "File 'c:/root/src/file3.tsx' does not exist.",
     "File 'c:/root/src/file3.d.ts' does not exist.",
+    "File 'c:/root/src/file3.js' does not exist.",
+    "File 'c:/root/src/file3.jsx' does not exist.",
     "File 'c:/root/src/file3/package.json' does not exist.",
     "File 'c:/root/src/file3/index.ts' does not exist.",
     "File 'c:/root/src/file3/index.tsx' does not exist.",
diff --git a/tests/baselines/reference/typeRootsFromMultipleNodeModulesDirectories.trace.json b/tests/baselines/reference/typeRootsFromMultipleNodeModulesDirectories.trace.json
index c734e57cda24f..a541ee310ef7a 100644
--- a/tests/baselines/reference/typeRootsFromMultipleNodeModulesDirectories.trace.json
+++ b/tests/baselines/reference/typeRootsFromMultipleNodeModulesDirectories.trace.json
@@ -5,45 +5,69 @@
     "File '/foo/bar/node_modules/xyz.ts' does not exist.",
     "File '/foo/bar/node_modules/xyz.tsx' does not exist.",
     "File '/foo/bar/node_modules/xyz.d.ts' does not exist.",
+    "File '/foo/bar/node_modules/xyz.js' does not exist.",
+    "File '/foo/bar/node_modules/xyz.jsx' does not exist.",
     "File '/foo/bar/node_modules/xyz/package.json' does not exist.",
     "File '/foo/bar/node_modules/xyz/index.ts' does not exist.",
     "File '/foo/bar/node_modules/xyz/index.tsx' does not exist.",
     "File '/foo/bar/node_modules/xyz/index.d.ts' does not exist.",
+    "File '/foo/bar/node_modules/xyz/index.js' does not exist.",
+    "File '/foo/bar/node_modules/xyz/index.jsx' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz.ts' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz.tsx' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz.d.ts' does not exist.",
+    "File '/foo/bar/node_modules/@types/xyz.js' does not exist.",
+    "File '/foo/bar/node_modules/@types/xyz.jsx' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz/package.json' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz/index.ts' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz/index.tsx' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz/index.d.ts' does not exist.",
+    "File '/foo/bar/node_modules/@types/xyz/index.js' does not exist.",
+    "File '/foo/bar/node_modules/@types/xyz/index.jsx' does not exist.",
     "File '/foo/node_modules/xyz.ts' does not exist.",
     "File '/foo/node_modules/xyz.tsx' does not exist.",
     "File '/foo/node_modules/xyz.d.ts' does not exist.",
+    "File '/foo/node_modules/xyz.js' does not exist.",
+    "File '/foo/node_modules/xyz.jsx' does not exist.",
     "File '/foo/node_modules/xyz/package.json' does not exist.",
     "File '/foo/node_modules/xyz/index.ts' does not exist.",
     "File '/foo/node_modules/xyz/index.tsx' does not exist.",
     "File '/foo/node_modules/xyz/index.d.ts' does not exist.",
+    "File '/foo/node_modules/xyz/index.js' does not exist.",
+    "File '/foo/node_modules/xyz/index.jsx' does not exist.",
     "File '/foo/node_modules/@types/xyz.ts' does not exist.",
     "File '/foo/node_modules/@types/xyz.tsx' does not exist.",
     "File '/foo/node_modules/@types/xyz.d.ts' does not exist.",
+    "File '/foo/node_modules/@types/xyz.js' does not exist.",
+    "File '/foo/node_modules/@types/xyz.jsx' does not exist.",
     "File '/foo/node_modules/@types/xyz/package.json' does not exist.",
     "File '/foo/node_modules/@types/xyz/index.ts' does not exist.",
     "File '/foo/node_modules/@types/xyz/index.tsx' does not exist.",
     "File '/foo/node_modules/@types/xyz/index.d.ts' does not exist.",
+    "File '/foo/node_modules/@types/xyz/index.js' does not exist.",
+    "File '/foo/node_modules/@types/xyz/index.jsx' does not exist.",
     "File '/node_modules/xyz.ts' does not exist.",
     "File '/node_modules/xyz.tsx' does not exist.",
     "File '/node_modules/xyz.d.ts' does not exist.",
+    "File '/node_modules/xyz.js' does not exist.",
+    "File '/node_modules/xyz.jsx' does not exist.",
     "File '/node_modules/xyz/package.json' does not exist.",
     "File '/node_modules/xyz/index.ts' does not exist.",
     "File '/node_modules/xyz/index.tsx' does not exist.",
     "File '/node_modules/xyz/index.d.ts' does not exist.",
+    "File '/node_modules/xyz/index.js' does not exist.",
+    "File '/node_modules/xyz/index.jsx' does not exist.",
     "File '/node_modules/@types/xyz.ts' does not exist.",
     "File '/node_modules/@types/xyz.tsx' does not exist.",
     "File '/node_modules/@types/xyz.d.ts' does not exist.",
+    "File '/node_modules/@types/xyz.js' does not exist.",
+    "File '/node_modules/@types/xyz.jsx' does not exist.",
     "File '/node_modules/@types/xyz/package.json' does not exist.",
     "File '/node_modules/@types/xyz/index.ts' does not exist.",
     "File '/node_modules/@types/xyz/index.tsx' does not exist.",
     "File '/node_modules/@types/xyz/index.d.ts' does not exist.",
+    "File '/node_modules/@types/xyz/index.js' does not exist.",
+    "File '/node_modules/@types/xyz/index.jsx' does not exist.",
     "======== Module name 'xyz' was not resolved. ========",
     "======== Resolving module 'pdq' from '/foo/bar/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
@@ -51,45 +75,69 @@
     "File '/foo/bar/node_modules/pdq.ts' does not exist.",
     "File '/foo/bar/node_modules/pdq.tsx' does not exist.",
     "File '/foo/bar/node_modules/pdq.d.ts' does not exist.",
+    "File '/foo/bar/node_modules/pdq.js' does not exist.",
+    "File '/foo/bar/node_modules/pdq.jsx' does not exist.",
     "File '/foo/bar/node_modules/pdq/package.json' does not exist.",
     "File '/foo/bar/node_modules/pdq/index.ts' does not exist.",
     "File '/foo/bar/node_modules/pdq/index.tsx' does not exist.",
     "File '/foo/bar/node_modules/pdq/index.d.ts' does not exist.",
+    "File '/foo/bar/node_modules/pdq/index.js' does not exist.",
+    "File '/foo/bar/node_modules/pdq/index.jsx' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq.ts' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq.tsx' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq.d.ts' does not exist.",
+    "File '/foo/bar/node_modules/@types/pdq.js' does not exist.",
+    "File '/foo/bar/node_modules/@types/pdq.jsx' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq/package.json' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq/index.ts' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq/index.tsx' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq/index.d.ts' does not exist.",
+    "File '/foo/bar/node_modules/@types/pdq/index.js' does not exist.",
+    "File '/foo/bar/node_modules/@types/pdq/index.jsx' does not exist.",
     "File '/foo/node_modules/pdq.ts' does not exist.",
     "File '/foo/node_modules/pdq.tsx' does not exist.",
     "File '/foo/node_modules/pdq.d.ts' does not exist.",
+    "File '/foo/node_modules/pdq.js' does not exist.",
+    "File '/foo/node_modules/pdq.jsx' does not exist.",
     "File '/foo/node_modules/pdq/package.json' does not exist.",
     "File '/foo/node_modules/pdq/index.ts' does not exist.",
     "File '/foo/node_modules/pdq/index.tsx' does not exist.",
     "File '/foo/node_modules/pdq/index.d.ts' does not exist.",
+    "File '/foo/node_modules/pdq/index.js' does not exist.",
+    "File '/foo/node_modules/pdq/index.jsx' does not exist.",
     "File '/foo/node_modules/@types/pdq.ts' does not exist.",
     "File '/foo/node_modules/@types/pdq.tsx' does not exist.",
     "File '/foo/node_modules/@types/pdq.d.ts' does not exist.",
+    "File '/foo/node_modules/@types/pdq.js' does not exist.",
+    "File '/foo/node_modules/@types/pdq.jsx' does not exist.",
     "File '/foo/node_modules/@types/pdq/package.json' does not exist.",
     "File '/foo/node_modules/@types/pdq/index.ts' does not exist.",
     "File '/foo/node_modules/@types/pdq/index.tsx' does not exist.",
     "File '/foo/node_modules/@types/pdq/index.d.ts' does not exist.",
+    "File '/foo/node_modules/@types/pdq/index.js' does not exist.",
+    "File '/foo/node_modules/@types/pdq/index.jsx' does not exist.",
     "File '/node_modules/pdq.ts' does not exist.",
     "File '/node_modules/pdq.tsx' does not exist.",
     "File '/node_modules/pdq.d.ts' does not exist.",
+    "File '/node_modules/pdq.js' does not exist.",
+    "File '/node_modules/pdq.jsx' does not exist.",
     "File '/node_modules/pdq/package.json' does not exist.",
     "File '/node_modules/pdq/index.ts' does not exist.",
     "File '/node_modules/pdq/index.tsx' does not exist.",
     "File '/node_modules/pdq/index.d.ts' does not exist.",
+    "File '/node_modules/pdq/index.js' does not exist.",
+    "File '/node_modules/pdq/index.jsx' does not exist.",
     "File '/node_modules/@types/pdq.ts' does not exist.",
     "File '/node_modules/@types/pdq.tsx' does not exist.",
     "File '/node_modules/@types/pdq.d.ts' does not exist.",
+    "File '/node_modules/@types/pdq.js' does not exist.",
+    "File '/node_modules/@types/pdq.jsx' does not exist.",
     "File '/node_modules/@types/pdq/package.json' does not exist.",
     "File '/node_modules/@types/pdq/index.ts' does not exist.",
     "File '/node_modules/@types/pdq/index.tsx' does not exist.",
     "File '/node_modules/@types/pdq/index.d.ts' does not exist.",
+    "File '/node_modules/@types/pdq/index.js' does not exist.",
+    "File '/node_modules/@types/pdq/index.jsx' does not exist.",
     "======== Module name 'pdq' was not resolved. ========",
     "======== Resolving module 'abc' from '/foo/bar/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
@@ -97,45 +145,69 @@
     "File '/foo/bar/node_modules/abc.ts' does not exist.",
     "File '/foo/bar/node_modules/abc.tsx' does not exist.",
     "File '/foo/bar/node_modules/abc.d.ts' does not exist.",
+    "File '/foo/bar/node_modules/abc.js' does not exist.",
+    "File '/foo/bar/node_modules/abc.jsx' does not exist.",
     "File '/foo/bar/node_modules/abc/package.json' does not exist.",
     "File '/foo/bar/node_modules/abc/index.ts' does not exist.",
     "File '/foo/bar/node_modules/abc/index.tsx' does not exist.",
     "File '/foo/bar/node_modules/abc/index.d.ts' does not exist.",
+    "File '/foo/bar/node_modules/abc/index.js' does not exist.",
+    "File '/foo/bar/node_modules/abc/index.jsx' does not exist.",
     "File '/foo/bar/node_modules/@types/abc.ts' does not exist.",
     "File '/foo/bar/node_modules/@types/abc.tsx' does not exist.",
     "File '/foo/bar/node_modules/@types/abc.d.ts' does not exist.",
+    "File '/foo/bar/node_modules/@types/abc.js' does not exist.",
+    "File '/foo/bar/node_modules/@types/abc.jsx' does not exist.",
     "File '/foo/bar/node_modules/@types/abc/package.json' does not exist.",
     "File '/foo/bar/node_modules/@types/abc/index.ts' does not exist.",
     "File '/foo/bar/node_modules/@types/abc/index.tsx' does not exist.",
     "File '/foo/bar/node_modules/@types/abc/index.d.ts' does not exist.",
+    "File '/foo/bar/node_modules/@types/abc/index.js' does not exist.",
+    "File '/foo/bar/node_modules/@types/abc/index.jsx' does not exist.",
     "File '/foo/node_modules/abc.ts' does not exist.",
     "File '/foo/node_modules/abc.tsx' does not exist.",
     "File '/foo/node_modules/abc.d.ts' does not exist.",
+    "File '/foo/node_modules/abc.js' does not exist.",
+    "File '/foo/node_modules/abc.jsx' does not exist.",
     "File '/foo/node_modules/abc/package.json' does not exist.",
     "File '/foo/node_modules/abc/index.ts' does not exist.",
     "File '/foo/node_modules/abc/index.tsx' does not exist.",
     "File '/foo/node_modules/abc/index.d.ts' does not exist.",
+    "File '/foo/node_modules/abc/index.js' does not exist.",
+    "File '/foo/node_modules/abc/index.jsx' does not exist.",
     "File '/foo/node_modules/@types/abc.ts' does not exist.",
     "File '/foo/node_modules/@types/abc.tsx' does not exist.",
     "File '/foo/node_modules/@types/abc.d.ts' does not exist.",
+    "File '/foo/node_modules/@types/abc.js' does not exist.",
+    "File '/foo/node_modules/@types/abc.jsx' does not exist.",
     "File '/foo/node_modules/@types/abc/package.json' does not exist.",
     "File '/foo/node_modules/@types/abc/index.ts' does not exist.",
     "File '/foo/node_modules/@types/abc/index.tsx' does not exist.",
     "File '/foo/node_modules/@types/abc/index.d.ts' does not exist.",
+    "File '/foo/node_modules/@types/abc/index.js' does not exist.",
+    "File '/foo/node_modules/@types/abc/index.jsx' does not exist.",
     "File '/node_modules/abc.ts' does not exist.",
     "File '/node_modules/abc.tsx' does not exist.",
     "File '/node_modules/abc.d.ts' does not exist.",
+    "File '/node_modules/abc.js' does not exist.",
+    "File '/node_modules/abc.jsx' does not exist.",
     "File '/node_modules/abc/package.json' does not exist.",
     "File '/node_modules/abc/index.ts' does not exist.",
     "File '/node_modules/abc/index.tsx' does not exist.",
     "File '/node_modules/abc/index.d.ts' does not exist.",
+    "File '/node_modules/abc/index.js' does not exist.",
+    "File '/node_modules/abc/index.jsx' does not exist.",
     "File '/node_modules/@types/abc.ts' does not exist.",
     "File '/node_modules/@types/abc.tsx' does not exist.",
     "File '/node_modules/@types/abc.d.ts' does not exist.",
+    "File '/node_modules/@types/abc.js' does not exist.",
+    "File '/node_modules/@types/abc.jsx' does not exist.",
     "File '/node_modules/@types/abc/package.json' does not exist.",
     "File '/node_modules/@types/abc/index.ts' does not exist.",
     "File '/node_modules/@types/abc/index.tsx' does not exist.",
     "File '/node_modules/@types/abc/index.d.ts' does not exist.",
+    "File '/node_modules/@types/abc/index.js' does not exist.",
+    "File '/node_modules/@types/abc/index.jsx' does not exist.",
     "======== Module name 'abc' was not resolved. ========",
     "======== Resolving type reference directive 'grumpy', containing file '/src/__inferred type names__.ts', root directory '/foo/node_modules/@types,/node_modules/@types'. ========",
     "Resolving with primary search path '/foo/node_modules/@types, /node_modules/@types'",
diff --git a/tests/baselines/reference/typeRootsFromNodeModulesInParentDirectory.trace.json b/tests/baselines/reference/typeRootsFromNodeModulesInParentDirectory.trace.json
index 7782ffc4ebf86..12a0bc0d23ab9 100644
--- a/tests/baselines/reference/typeRootsFromNodeModulesInParentDirectory.trace.json
+++ b/tests/baselines/reference/typeRootsFromNodeModulesInParentDirectory.trace.json
@@ -5,31 +5,47 @@
     "File '/src/node_modules/xyz.ts' does not exist.",
     "File '/src/node_modules/xyz.tsx' does not exist.",
     "File '/src/node_modules/xyz.d.ts' does not exist.",
+    "File '/src/node_modules/xyz.js' does not exist.",
+    "File '/src/node_modules/xyz.jsx' does not exist.",
     "File '/src/node_modules/xyz/package.json' does not exist.",
     "File '/src/node_modules/xyz/index.ts' does not exist.",
     "File '/src/node_modules/xyz/index.tsx' does not exist.",
     "File '/src/node_modules/xyz/index.d.ts' does not exist.",
+    "File '/src/node_modules/xyz/index.js' does not exist.",
+    "File '/src/node_modules/xyz/index.jsx' does not exist.",
     "File '/src/node_modules/@types/xyz.ts' does not exist.",
     "File '/src/node_modules/@types/xyz.tsx' does not exist.",
     "File '/src/node_modules/@types/xyz.d.ts' does not exist.",
+    "File '/src/node_modules/@types/xyz.js' does not exist.",
+    "File '/src/node_modules/@types/xyz.jsx' does not exist.",
     "File '/src/node_modules/@types/xyz/package.json' does not exist.",
     "File '/src/node_modules/@types/xyz/index.ts' does not exist.",
     "File '/src/node_modules/@types/xyz/index.tsx' does not exist.",
     "File '/src/node_modules/@types/xyz/index.d.ts' does not exist.",
+    "File '/src/node_modules/@types/xyz/index.js' does not exist.",
+    "File '/src/node_modules/@types/xyz/index.jsx' does not exist.",
     "File '/node_modules/xyz.ts' does not exist.",
     "File '/node_modules/xyz.tsx' does not exist.",
     "File '/node_modules/xyz.d.ts' does not exist.",
+    "File '/node_modules/xyz.js' does not exist.",
+    "File '/node_modules/xyz.jsx' does not exist.",
     "File '/node_modules/xyz/package.json' does not exist.",
     "File '/node_modules/xyz/index.ts' does not exist.",
     "File '/node_modules/xyz/index.tsx' does not exist.",
     "File '/node_modules/xyz/index.d.ts' does not exist.",
+    "File '/node_modules/xyz/index.js' does not exist.",
+    "File '/node_modules/xyz/index.jsx' does not exist.",
     "File '/node_modules/@types/xyz.ts' does not exist.",
     "File '/node_modules/@types/xyz.tsx' does not exist.",
     "File '/node_modules/@types/xyz.d.ts' does not exist.",
+    "File '/node_modules/@types/xyz.js' does not exist.",
+    "File '/node_modules/@types/xyz.jsx' does not exist.",
     "File '/node_modules/@types/xyz/package.json' does not exist.",
     "File '/node_modules/@types/xyz/index.ts' does not exist.",
     "File '/node_modules/@types/xyz/index.tsx' does not exist.",
     "File '/node_modules/@types/xyz/index.d.ts' does not exist.",
+    "File '/node_modules/@types/xyz/index.js' does not exist.",
+    "File '/node_modules/@types/xyz/index.jsx' does not exist.",
     "======== Module name 'xyz' was not resolved. ========",
     "======== Resolving type reference directive 'foo', containing file '/src/__inferred type names__.ts', root directory '/node_modules/@types'. ========",
     "Resolving with primary search path '/node_modules/@types'",
diff --git a/tests/baselines/reference/typingsLookup4.trace.json b/tests/baselines/reference/typingsLookup4.trace.json
index 4bca8456f5846..e5ad33fd0d2d4 100644
--- a/tests/baselines/reference/typingsLookup4.trace.json
+++ b/tests/baselines/reference/typingsLookup4.trace.json
@@ -5,13 +5,19 @@
     "File '/node_modules/jquery.ts' does not exist.",
     "File '/node_modules/jquery.tsx' does not exist.",
     "File '/node_modules/jquery.d.ts' does not exist.",
+    "File '/node_modules/jquery.js' does not exist.",
+    "File '/node_modules/jquery.jsx' does not exist.",
     "File '/node_modules/jquery/package.json' does not exist.",
     "File '/node_modules/jquery/index.ts' does not exist.",
     "File '/node_modules/jquery/index.tsx' does not exist.",
     "File '/node_modules/jquery/index.d.ts' does not exist.",
+    "File '/node_modules/jquery/index.js' does not exist.",
+    "File '/node_modules/jquery/index.jsx' does not exist.",
     "File '/node_modules/@types/jquery.ts' does not exist.",
     "File '/node_modules/@types/jquery.tsx' does not exist.",
     "File '/node_modules/@types/jquery.d.ts' does not exist.",
+    "File '/node_modules/@types/jquery.js' does not exist.",
+    "File '/node_modules/@types/jquery.jsx' does not exist.",
     "Found 'package.json' at '/node_modules/@types/jquery/package.json'.",
     "'package.json' has 'typings' field 'jquery.d.ts' that references '/node_modules/@types/jquery/jquery.d.ts'.",
     "File '/node_modules/@types/jquery/jquery.d.ts' exist - use it as a name resolution result.",
@@ -23,13 +29,19 @@
     "File '/node_modules/kquery.ts' does not exist.",
     "File '/node_modules/kquery.tsx' does not exist.",
     "File '/node_modules/kquery.d.ts' does not exist.",
+    "File '/node_modules/kquery.js' does not exist.",
+    "File '/node_modules/kquery.jsx' does not exist.",
     "File '/node_modules/kquery/package.json' does not exist.",
     "File '/node_modules/kquery/index.ts' does not exist.",
     "File '/node_modules/kquery/index.tsx' does not exist.",
     "File '/node_modules/kquery/index.d.ts' does not exist.",
+    "File '/node_modules/kquery/index.js' does not exist.",
+    "File '/node_modules/kquery/index.jsx' does not exist.",
     "File '/node_modules/@types/kquery.ts' does not exist.",
     "File '/node_modules/@types/kquery.tsx' does not exist.",
     "File '/node_modules/@types/kquery.d.ts' does not exist.",
+    "File '/node_modules/@types/kquery.js' does not exist.",
+    "File '/node_modules/@types/kquery.jsx' does not exist.",
     "Found 'package.json' at '/node_modules/@types/kquery/package.json'.",
     "'package.json' has 'typings' field 'kquery' that references '/node_modules/@types/kquery/kquery'.",
     "File '/node_modules/@types/kquery/kquery' does not exist.",
@@ -44,13 +56,19 @@
     "File '/node_modules/lquery.ts' does not exist.",
     "File '/node_modules/lquery.tsx' does not exist.",
     "File '/node_modules/lquery.d.ts' does not exist.",
+    "File '/node_modules/lquery.js' does not exist.",
+    "File '/node_modules/lquery.jsx' does not exist.",
     "File '/node_modules/lquery/package.json' does not exist.",
     "File '/node_modules/lquery/index.ts' does not exist.",
     "File '/node_modules/lquery/index.tsx' does not exist.",
     "File '/node_modules/lquery/index.d.ts' does not exist.",
+    "File '/node_modules/lquery/index.js' does not exist.",
+    "File '/node_modules/lquery/index.jsx' does not exist.",
     "File '/node_modules/@types/lquery.ts' does not exist.",
     "File '/node_modules/@types/lquery.tsx' does not exist.",
     "File '/node_modules/@types/lquery.d.ts' does not exist.",
+    "File '/node_modules/@types/lquery.js' does not exist.",
+    "File '/node_modules/@types/lquery.jsx' does not exist.",
     "Found 'package.json' at '/node_modules/@types/lquery/package.json'.",
     "'package.json' has 'typings' field 'lquery' that references '/node_modules/@types/lquery/lquery'.",
     "File '/node_modules/@types/lquery/lquery' does not exist.",
@@ -68,6 +86,8 @@
     "Found 'package.json' at '/node_modules/@types/kquery/package.json'.",
     "'package.json' has 'typings' field 'kquery' that references '/node_modules/@types/kquery/kquery'.",
     "File '/node_modules/@types/kquery/kquery' does not exist.",
+    "File '/node_modules/@types/kquery/kquery.ts' does not exist.",
+    "File '/node_modules/@types/kquery/kquery.tsx' does not exist.",
     "File '/node_modules/@types/kquery/kquery.d.ts' exist - use it as a name resolution result.",
     "======== Type reference directive 'kquery' was successfully resolved to '/node_modules/@types/kquery/kquery.d.ts', primary: true. ========",
     "======== Resolving type reference directive 'lquery', containing file '/__inferred type names__.ts', root directory '/node_modules/@types'. ========",
@@ -75,19 +95,6 @@
     "Found 'package.json' at '/node_modules/@types/lquery/package.json'.",
     "'package.json' has 'typings' field 'lquery' that references '/node_modules/@types/lquery/lquery'.",
     "File '/node_modules/@types/lquery/lquery' does not exist.",
-    "File '/node_modules/@types/lquery/lquery.d.ts' does not exist.",
-    "File '/node_modules/@types/lquery/index.d.ts' does not exist.",
-    "Looking up in 'node_modules' folder, initial location '/'",
-    "File '/node_modules/lquery.ts' does not exist.",
-    "File '/node_modules/lquery.d.ts' does not exist.",
-    "File '/node_modules/lquery/package.json' does not exist.",
-    "File '/node_modules/lquery/index.ts' does not exist.",
-    "File '/node_modules/lquery/index.d.ts' does not exist.",
-    "File '/node_modules/@types/lquery.ts' does not exist.",
-    "File '/node_modules/@types/lquery.d.ts' does not exist.",
-    "Found 'package.json' at '/node_modules/@types/lquery/package.json'.",
-    "'package.json' has 'typings' field 'lquery' that references '/node_modules/@types/lquery/lquery'.",
-    "File '/node_modules/@types/lquery/lquery' does not exist.",
     "File '/node_modules/@types/lquery/lquery.ts' exist - use it as a name resolution result.",
-    "======== Type reference directive 'lquery' was successfully resolved to '/node_modules/@types/lquery/lquery.ts', primary: false. ========"
+    "======== Type reference directive 'lquery' was successfully resolved to '/node_modules/@types/lquery/lquery.ts', primary: true. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/typingsLookupAmd.trace.json b/tests/baselines/reference/typingsLookupAmd.trace.json
index 5c83757454c4b..732e990065841 100644
--- a/tests/baselines/reference/typingsLookupAmd.trace.json
+++ b/tests/baselines/reference/typingsLookupAmd.trace.json
@@ -2,53 +2,109 @@
     "======== Resolving module 'b' from '/x/y/foo.ts'. ========",
     "Module resolution kind is not specified, using 'Classic'.",
     "File '/x/y/b.ts' does not exist.",
+    "File '/x/y/b.tsx' does not exist.",
     "File '/x/y/b.d.ts' does not exist.",
+    "File '/x/y/b.js' does not exist.",
+    "File '/x/y/b.jsx' does not exist.",
     "File '/x/b.ts' does not exist.",
+    "File '/x/b.tsx' does not exist.",
     "File '/x/b.d.ts' does not exist.",
+    "File '/x/b.js' does not exist.",
+    "File '/x/b.jsx' does not exist.",
     "File '/b.ts' does not exist.",
+    "File '/b.tsx' does not exist.",
     "File '/b.d.ts' does not exist.",
+    "File '/b.js' does not exist.",
+    "File '/b.jsx' does not exist.",
     "File '/x/y/node_modules/@types/b.ts' does not exist.",
+    "File '/x/y/node_modules/@types/b.tsx' does not exist.",
     "File '/x/y/node_modules/@types/b.d.ts' does not exist.",
+    "File '/x/y/node_modules/@types/b.js' does not exist.",
+    "File '/x/y/node_modules/@types/b.jsx' does not exist.",
     "File '/x/y/node_modules/@types/b/package.json' does not exist.",
     "File '/x/y/node_modules/@types/b/index.ts' does not exist.",
+    "File '/x/y/node_modules/@types/b/index.tsx' does not exist.",
     "File '/x/y/node_modules/@types/b/index.d.ts' does not exist.",
+    "File '/x/y/node_modules/@types/b/index.js' does not exist.",
+    "File '/x/y/node_modules/@types/b/index.jsx' does not exist.",
     "File '/x/node_modules/@types/b.ts' does not exist.",
+    "File '/x/node_modules/@types/b.tsx' does not exist.",
     "File '/x/node_modules/@types/b.d.ts' does not exist.",
+    "File '/x/node_modules/@types/b.js' does not exist.",
+    "File '/x/node_modules/@types/b.jsx' does not exist.",
     "File '/x/node_modules/@types/b/package.json' does not exist.",
     "File '/x/node_modules/@types/b/index.ts' does not exist.",
+    "File '/x/node_modules/@types/b/index.tsx' does not exist.",
     "File '/x/node_modules/@types/b/index.d.ts' exist - use it as a name resolution result.",
     "======== Module name 'b' was successfully resolved to '/x/node_modules/@types/b/index.d.ts'. ========",
     "======== Resolving module 'a' from '/x/node_modules/@types/b/index.d.ts'. ========",
     "Module resolution kind is not specified, using 'Classic'.",
     "File '/x/node_modules/@types/b/a.ts' does not exist.",
+    "File '/x/node_modules/@types/b/a.tsx' does not exist.",
     "File '/x/node_modules/@types/b/a.d.ts' does not exist.",
+    "File '/x/node_modules/@types/b/a.js' does not exist.",
+    "File '/x/node_modules/@types/b/a.jsx' does not exist.",
     "File '/x/node_modules/@types/a.ts' does not exist.",
+    "File '/x/node_modules/@types/a.tsx' does not exist.",
     "File '/x/node_modules/@types/a.d.ts' does not exist.",
+    "File '/x/node_modules/@types/a.js' does not exist.",
+    "File '/x/node_modules/@types/a.jsx' does not exist.",
     "File '/x/node_modules/a.ts' does not exist.",
+    "File '/x/node_modules/a.tsx' does not exist.",
     "File '/x/node_modules/a.d.ts' does not exist.",
+    "File '/x/node_modules/a.js' does not exist.",
+    "File '/x/node_modules/a.jsx' does not exist.",
     "File '/x/a.ts' does not exist.",
+    "File '/x/a.tsx' does not exist.",
     "File '/x/a.d.ts' does not exist.",
+    "File '/x/a.js' does not exist.",
+    "File '/x/a.jsx' does not exist.",
     "File '/a.ts' does not exist.",
+    "File '/a.tsx' does not exist.",
     "File '/a.d.ts' does not exist.",
+    "File '/a.js' does not exist.",
+    "File '/a.jsx' does not exist.",
     "File '/x/node_modules/@types/b/node_modules/@types/a.ts' does not exist.",
+    "File '/x/node_modules/@types/b/node_modules/@types/a.tsx' does not exist.",
     "File '/x/node_modules/@types/b/node_modules/@types/a.d.ts' does not exist.",
+    "File '/x/node_modules/@types/b/node_modules/@types/a.js' does not exist.",
+    "File '/x/node_modules/@types/b/node_modules/@types/a.jsx' does not exist.",
     "File '/x/node_modules/@types/b/node_modules/@types/a/package.json' does not exist.",
     "File '/x/node_modules/@types/b/node_modules/@types/a/index.ts' does not exist.",
+    "File '/x/node_modules/@types/b/node_modules/@types/a/index.tsx' does not exist.",
     "File '/x/node_modules/@types/b/node_modules/@types/a/index.d.ts' does not exist.",
+    "File '/x/node_modules/@types/b/node_modules/@types/a/index.js' does not exist.",
+    "File '/x/node_modules/@types/b/node_modules/@types/a/index.jsx' does not exist.",
     "File '/x/node_modules/@types/node_modules/@types/a.ts' does not exist.",
+    "File '/x/node_modules/@types/node_modules/@types/a.tsx' does not exist.",
     "File '/x/node_modules/@types/node_modules/@types/a.d.ts' does not exist.",
+    "File '/x/node_modules/@types/node_modules/@types/a.js' does not exist.",
+    "File '/x/node_modules/@types/node_modules/@types/a.jsx' does not exist.",
     "File '/x/node_modules/@types/node_modules/@types/a/package.json' does not exist.",
     "File '/x/node_modules/@types/node_modules/@types/a/index.ts' does not exist.",
+    "File '/x/node_modules/@types/node_modules/@types/a/index.tsx' does not exist.",
     "File '/x/node_modules/@types/node_modules/@types/a/index.d.ts' does not exist.",
+    "File '/x/node_modules/@types/node_modules/@types/a/index.js' does not exist.",
+    "File '/x/node_modules/@types/node_modules/@types/a/index.jsx' does not exist.",
     "File '/x/node_modules/@types/a.ts' does not exist.",
+    "File '/x/node_modules/@types/a.tsx' does not exist.",
     "File '/x/node_modules/@types/a.d.ts' does not exist.",
+    "File '/x/node_modules/@types/a.js' does not exist.",
+    "File '/x/node_modules/@types/a.jsx' does not exist.",
     "File '/x/node_modules/@types/a/package.json' does not exist.",
     "File '/x/node_modules/@types/a/index.ts' does not exist.",
+    "File '/x/node_modules/@types/a/index.tsx' does not exist.",
     "File '/x/node_modules/@types/a/index.d.ts' does not exist.",
+    "File '/x/node_modules/@types/a/index.js' does not exist.",
+    "File '/x/node_modules/@types/a/index.jsx' does not exist.",
     "File '/node_modules/@types/a.ts' does not exist.",
+    "File '/node_modules/@types/a.tsx' does not exist.",
     "File '/node_modules/@types/a.d.ts' does not exist.",
+    "File '/node_modules/@types/a.js' does not exist.",
+    "File '/node_modules/@types/a.jsx' does not exist.",
     "File '/node_modules/@types/a/package.json' does not exist.",
     "File '/node_modules/@types/a/index.ts' does not exist.",
+    "File '/node_modules/@types/a/index.tsx' does not exist.",
     "File '/node_modules/@types/a/index.d.ts' exist - use it as a name resolution result.",
     "======== Module name 'a' was successfully resolved to '/node_modules/@types/a/index.d.ts'. ========",
     "======== Resolving type reference directive 'a', containing file '/__inferred type names__.ts', root directory '/node_modules/@types'. ========",
diff --git a/tests/cases/compiler/moduleResolutionNoTs.ts b/tests/cases/compiler/moduleResolutionNoTs.ts
index 2051bc259bf0e..fc92d72946432 100644
--- a/tests/cases/compiler/moduleResolutionNoTs.ts
+++ b/tests/cases/compiler/moduleResolutionNoTs.ts
@@ -1,3 +1,4 @@
+// @jsx: Preserve
 // @filename: x.ts
 export default 0;
 
diff --git a/tests/cases/compiler/moduleResolutionWithExtensions_notSupported.ts b/tests/cases/compiler/moduleResolutionWithExtensions_notSupported.ts
new file mode 100644
index 0000000000000..58b039ad8c2d6
--- /dev/null
+++ b/tests/cases/compiler/moduleResolutionWithExtensions_notSupported.ts
@@ -0,0 +1,13 @@
+// @noImplicitReferences: true
+// @traceResolution: true
+
+// @Filename: /tsx.tsx
+
+// @Filename: /jsx.jsx
+
+// @Filename: /js.js
+
+// @Filename: /a.ts
+import tsx from "./tsx";
+import jsx from "./jsx";
+import js from "./js";
diff --git a/tests/cases/compiler/moduleResolutionWithExtensions_notSupported2.ts b/tests/cases/compiler/moduleResolutionWithExtensions_notSupported2.ts
new file mode 100644
index 0000000000000..42741fabad6c0
--- /dev/null
+++ b/tests/cases/compiler/moduleResolutionWithExtensions_notSupported2.ts
@@ -0,0 +1,9 @@
+// @noImplicitReferences: true
+// @allowJs: true
+// @traceResolution: true
+// Test the error message if we have `--allowJs` but not `--jsx`.
+
+// @Filename: /jsx.jsx
+
+// @Filename: /a.ts
+import jsx from "./jsx";
diff --git a/tests/cases/compiler/moduleResolutionWithExtensions_preferTs.ts b/tests/cases/compiler/moduleResolutionWithExtensions_preferTs.ts
new file mode 100644
index 0000000000000..5688408b72b43
--- /dev/null
+++ b/tests/cases/compiler/moduleResolutionWithExtensions_preferTs.ts
@@ -0,0 +1,10 @@
+// @noImplicitReferences: true
+// @traceResolution: true
+
+// @Filename: /b.js
+
+// @Filename: /b/index.ts
+export default 0;
+
+// @Filename: /a.ts
+import b from "./b";
diff --git a/tests/cases/compiler/moduleResolutionWithExtensions_withAmbientPresent.ts b/tests/cases/compiler/moduleResolutionWithExtensions_withAmbientPresent.ts
new file mode 100644
index 0000000000000..b41a7e52bd8bd
--- /dev/null
+++ b/tests/cases/compiler/moduleResolutionWithExtensions_withAmbientPresent.ts
@@ -0,0 +1,14 @@
+// @noImplicitReferences: true
+// @traceResolution: true
+// Allowjs is false, but this should *not* warn about the unused 'index.js'
+
+// @Filename: /node_modules/js/index.js
+
+// @Filename: /declarations.d.ts
+declare module "js" {
+    export const x = 0;
+}
+
+// @Filename: /a.ts
+/// <reference path="declarations.d.ts" />
+import { x } from "js";
diff --git a/tests/cases/conformance/references/library-reference-11.ts b/tests/cases/conformance/references/library-reference-11.ts
index 6708ceb4ab3fb..ec1de6e0e9df2 100644
--- a/tests/cases/conformance/references/library-reference-11.ts
+++ b/tests/cases/conformance/references/library-reference-11.ts
@@ -1,3 +1,4 @@
+// @allowJs: true
 // @noImplicitReferences: true
 // @traceResolution: true
 // @currentDirectory: /

From 7c53a1deb28775dc0a57509d653c93dbfe41fd76 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Tue, 18 Oct 2016 14:22:43 -0700
Subject: [PATCH 056/224] Instead of getResolutionOrDiagnostic, use
 getResolutionDiagnostic and avoid using resolution.resolvedFileName if the
 diagnostic is defined.

---
 src/compiler/checker.ts | 10 +++++-----
 src/compiler/program.ts | 26 ++++++++++++--------------
 2 files changed, 17 insertions(+), 19 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index ebf86484c4505..aec9cbec41db8 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -1366,8 +1366,8 @@ namespace ts {
             }
 
             const resolvedModule = getResolvedModule(getSourceFileOfNode(location), moduleReference);
-            const resolvedOrDiagnostic = resolvedModule && getResolutionOrDiagnostic(compilerOptions, resolvedModule);
-            const sourceFile = typeof resolvedOrDiagnostic === "string" && resolvedModule && host.getSourceFile(resolvedModule.resolvedFileName);
+            const resolutionDiagnostic = resolvedModule && getResolutionDiagnostic(compilerOptions, resolvedModule);
+            const sourceFile = resolvedModule && !resolutionDiagnostic && host.getSourceFile(resolvedModule.resolvedFileName);
             if (sourceFile) {
                 if (sourceFile.symbol) {
                     // merged symbol is module declaration symbol combined with all augmentations
@@ -1389,8 +1389,8 @@ namespace ts {
 
             if (moduleNotFoundError) {
                 // report errors only if it was requested
-                if (resolvedOrDiagnostic && typeof resolvedOrDiagnostic !== "string") {
-                    error(errorNode, resolvedOrDiagnostic.diag, moduleName, resolvedOrDiagnostic.file);
+                if (resolutionDiagnostic) {
+                    error(errorNode, resolutionDiagnostic, moduleName, resolvedModule.resolvedFileName);
                 }
                 else {
                     const tsExtension = tryExtractTypeScriptExtension(moduleName);
@@ -8543,7 +8543,7 @@ namespace ts {
         // An evolving array type tracks the element types that have so far been seen in an
         // 'x.push(value)' or 'x[n] = value' operation along the control flow graph. Evolving
         // array types are ultimately converted into manifest array types (using getFinalArrayType)
-        // and never escape the getFlowTypeOfReference function. 
+        // and never escape the getFlowTypeOfReference function.
         function createEvolvingArrayType(elementType: Type): AnonymousType {
             const result = <AnonymousType>createObjectType(TypeFlags.Anonymous);
             result.elementType = elementType;
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 43bc877bc583a..71ad88fea5ae9 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1318,10 +1318,8 @@ namespace ts {
                     }
 
                     const isFromNodeModulesSearch = resolution.isExternalLibraryImport;
-                    const isJsFileFromNodeModules = !resolution.resolvedTsFileName;
-                    const resolvedOrDiagnostic = getResolutionOrDiagnostic(options, resolution);
-                    // Ignore it if it has a bad extension (e.g. 'tsx' if we don't have '--allowJs') -- this will be reported by the checker, so just return undefined for now.
-                    const resolvedFileName = typeof resolvedOrDiagnostic === "string" ? resolvedOrDiagnostic : undefined;
+                    const isJsFileFromNodeModules = isFromNodeModulesSearch && !resolution.resolvedTsFileName;
+                    const resolvedFileName = resolution.resolvedFileName;
 
                     if (isFromNodeModulesSearch) {
                         currentNodeModulesDepth++;
@@ -1333,7 +1331,8 @@ namespace ts {
                     // - module name comes from the list of imports
                     // - it's not a top level JavaScript module that exceeded the search max
                     const elideImport = isJsFileFromNodeModules && currentNodeModulesDepth > maxNodeModuleJsDepth;
-                    const shouldAddFile = resolvedFileName && !options.noResolve && i < file.imports.length && !elideImport;
+                    // Don't add the file if it has a bad extension (e.g. 'tsx' if we don't have '--allowJs')
+                    const shouldAddFile = resolvedFileName && !getResolutionDiagnostic(options, resolution) && !options.noResolve && i < file.imports.length && !elideImport;
 
                     if (elideImport) {
                         modulesWithElidedImports[file.path] = true;
@@ -1580,24 +1579,23 @@ namespace ts {
 
     /* @internal */
     /**
-     * Extracts the file name from a ResolvedModule, or returns a DiagnosticMessage if we are not set up to use that kind of file.
+     * Returns a DiagnosticMessage if we can't use a resolved module due to its extension.
      * The DiagnosticMessage's parameters are the imported module name, and the filename it resolved to.
      */
-    export function getResolutionOrDiagnostic(options: CompilerOptions, { resolvedTsFileName: ts, resolvedJsFileName: js }: ResolvedModule): string | { file: string, diag: DiagnosticMessage } {
+    export function getResolutionDiagnostic(options: CompilerOptions, { resolvedTsFileName: ts, resolvedJsFileName: js }: ResolvedModule): DiagnosticMessage | undefined {
         if (ts) {
-            return !options.jsx && fileExtensionIs(ts, ".tsx")
-                ? { file: ts, diag: Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set }
-                : ts;
+            return !options.jsx && fileExtensionIs(ts, ".tsx") ? Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set : undefined;
         }
         else {
             if (!options.allowJs) {
-                return { file: js!, diag: Diagnostics.Module_0_was_resolved_to_1_but_allowJs_is_not_set };
+                return Diagnostics.Module_0_was_resolved_to_1_but_allowJs_is_not_set;
             }
             else if (!options.jsx && fileExtensionIs(js!, ".jsx")) {
-                return { file: js!, diag: Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set };
+                return Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set;
+            }
+            else {
+                return undefined;
             }
-            else
-                return js!;
         }
     }
 }

From df20cf33f1e166d86a6d45df9cf776665278938b Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Wed, 19 Oct 2016 12:55:57 -0700
Subject: [PATCH 057/224] Remove "ResolvedModuleFromHost" type and just make
 `resolvedTsFileName` and `resolvedJsFileName` optional properties

(but still automatically infer one of them to supply if the host supplied neither)
---
 src/compiler/types.ts     | 13 +++----------
 src/compiler/utilities.ts | 11 ++++++-----
 2 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index bc1a11febb14c..3e43d3ddf1052 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -3302,9 +3302,9 @@ namespace ts {
          */
         resolvedFileName: string;
         /** TypeScript (.d.ts, .ts, .tsx) file that the module was resolved to. This will be preferred over a JS file. */
-        resolvedTsFileName: string | undefined;
+        resolvedTsFileName?: string;
         /** JavaScript (or .jsx) file that the module was resolved to. This should be returned even if '--allowJs' (or '--jsx') is disabled. */
-        resolvedJsFileName: string | undefined;
+        resolvedJsFileName?: string;
         /**
          * Denotes if 'resolvedFileName' is isExternalLibraryImport and thus should be a proper external module:
          * - be a .d.ts file
@@ -3314,13 +3314,6 @@ namespace ts {
         isExternalLibraryImport: boolean;
     }
 
-    /**
-     * For backwards compatibility, a host may choose not to return `resolvedTsFileName` and `resolvedJsFileName` from a result ResolvedModule,
-     * in which case they will be inferred from the file extension.
-     * Prefer to return a full ResolvedModule.
-     */
-    export type ResolvedModuleFromHost = { resolvedFileName: string; isExternalLibraryImport: boolean } | ResolvedModule;
-
     export interface ResolvedModuleWithFailedLookupLocations {
         resolvedModule: ResolvedModule | undefined;
         failedLookupLocations: string[];
@@ -3358,7 +3351,7 @@ namespace ts {
          * If resolveModuleNames is implemented then implementation for members from ModuleResolutionHost can be just
          * 'throw new Error("NotImplemented")'
          */
-        resolveModuleNames?(moduleNames: string[], containingFile: string): ResolvedModuleFromHost[];
+        resolveModuleNames?(moduleNames: string[], containingFile: string): ResolvedModule[];
         /**
          * This method is a companion for 'resolveModuleNames' and is used to resolve 'types' references to actual type declaration files
          */
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 8f00987f7edd2..cd75ca6d4d488 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -118,18 +118,19 @@ namespace ts {
         sourceFile.resolvedModules[moduleNameText] = resolvedModule;
     }
 
-    /** Host may have omitted resolvedTsFileName and resolvedJsFileName, in which case we should infer them from the file extension of resolvedFileName. */
-    export function convertResolvedModuleFromHost(resolved: ResolvedModuleFromHost | undefined): ResolvedModule | undefined {
+    /** An older host may have omitted resolvedTsFileName and resolvedJsFileName, in which case we should infer them from the file extension of resolvedFileName. */
+    export function convertResolvedModuleFromHost(resolved: ResolvedModule | undefined): ResolvedModule | undefined {
         if (resolved === undefined) {
             return undefined;
         }
-        // `resolvedTsFileName` and `resolvedJsFileName` should be present as properties even if undefined.
-        else if ("resolvedTsFileName" in resolved) {
+        // At least one of `resolevdTsFileName` or `resolvedJsFileName` should be defined.
+        else if (resolved.resolvedTsFileName || resolved.resolvedJsFileName) {
             const { resolvedFileName, resolvedTsFileName, resolvedJsFileName } = resolved as ResolvedModule;
             Debug.assert(resolvedFileName === (resolvedTsFileName || resolvedJsFileName));
-            return resolved as ResolvedModule;
+            return resolved;
         }
         else {
+            // For backwards compatibility, if both `resolvedTsFileName` and `resolvedJsFileName` are undefined, we infer one of them to define.
             const { resolvedFileName, isExternalLibraryImport } = resolved;
             if (fileExtensionIsAny(resolvedFileName, supportedTypeScriptExtensions)) {
                 return { resolvedFileName, resolvedTsFileName: resolvedFileName, resolvedJsFileName: undefined, isExternalLibraryImport };

From 18c692a429421d7231d8a58b784c452e40176d82 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 19 Oct 2016 13:14:06 -0700
Subject: [PATCH 058/224] Remove type inference for spread types

---
 src/compiler/checker.ts | 88 +++++++++++------------------------------
 1 file changed, 23 insertions(+), 65 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 55d4361dc3e66..8e196da87de29 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -8045,8 +8045,7 @@ namespace ts {
             return !!(type.flags & TypeFlags.TypeParameter ||
                 type.flags & TypeFlags.Reference && forEach((<TypeReference>type).typeArguments, couldContainTypeParameters) ||
                 type.flags & TypeFlags.Anonymous && type.symbol && type.symbol.flags & (SymbolFlags.Method | SymbolFlags.TypeLiteral | SymbolFlags.Class) ||
-                type.flags & TypeFlags.UnionOrIntersection && couldUnionOrIntersectionContainTypeParameters(<UnionOrIntersectionType>type) ||
-                type.flags & TypeFlags.Spread && couldSpreadContainTypeParameters(type as SpreadType));
+                type.flags & TypeFlags.UnionOrIntersection && couldUnionOrIntersectionContainTypeParameters(<UnionOrIntersectionType>type));
         }
 
         function couldUnionOrIntersectionContainTypeParameters(type: UnionOrIntersectionType): boolean {
@@ -8056,11 +8055,6 @@ namespace ts {
             return type.couldContainTypeParameters;
         }
 
-        function couldSpreadContainTypeParameters(type: SpreadType): boolean {
-            return !!(type.right.flags & TypeFlags.TypeParameter ||
-                      type.left.flags & TypeFlags.Spread && (type.left as SpreadType).right.flags & TypeFlags.TypeParameter);
-        }
-
         function isTypeParameterAtTopLevel(type: Type, typeParameter: TypeParameter): boolean {
             return type === typeParameter || type.flags & TypeFlags.UnionOrIntersection && forEach((<UnionOrIntersectionType>type).types, t => isTypeParameterAtTopLevel(t, typeParameter));
         }
@@ -8124,16 +8118,6 @@ namespace ts {
                         target = removeTypesFromUnionOrIntersection(<UnionOrIntersectionType>target, matchingTypes);
                     }
                 }
-                if (source.flags & TypeFlags.Spread && target.flags & TypeFlags.Spread) {
-                    // only the last type parameter is a valid inference site,
-                    // and only if not followed by object literal properties.
-                    if ((source as SpreadType).right.flags & TypeFlags.TypeParameter &&
-                       (target as SpreadType).right.flags & TypeFlags.TypeParameter) {
-                        inferFromTypes((source as SpreadType).right, (target as SpreadType).right);
-                    }
-
-                    return;
-                }
                 if (target.flags & TypeFlags.TypeParameter) {
                     // If target is a type parameter, make an inference, unless the source type contains
                     // the anyFunctionType (the wildcard type that's used to avoid contextually typing functions).
@@ -8210,57 +8194,31 @@ namespace ts {
                 else {
                     source = getApparentType(source);
                     if (source.flags & TypeFlags.ObjectType) {
-                        if (target.flags & TypeFlags.Spread) {
-                            // with an object type as source, a spread target infers to its last type parameter it
-                            // contains, after removing any properties from a object type that precedes the type parameter
-                            // Note that the call to `typeDifference` creates a new anonymous type.
-                            const spread = target as SpreadType;
-                            const parameter = spread.right.flags & TypeFlags.TypeParameter ? spread.right : (spread.left as SpreadType).right;
-                            const object = spread.right.flags & TypeFlags.TypeParameter ? emptyObjectType : spread.right as ResolvedType;
-                            inferFromTypes(getTypeDifference(source, object), parameter);
-                            target = object;
+                        if (isInProcess(source, target)) {
+                            return;
                         }
-                        inferFromStructure(source, target);
-                    }
-                }
-            }
-
-            function inferFromStructure(source: Type, target: Type) {
-                if (isInProcess(source, target)) {
-                    return;
-                }
-                if (isDeeplyNestedGeneric(source, sourceStack, depth) && isDeeplyNestedGeneric(target, targetStack, depth)) {
-                    return;
-                }
-                const key = source.id + "," + target.id;
-                if (visited[key]) {
-                    return;
-                }
-                visited[key] = true;
-                if (depth === 0) {
-                    sourceStack = [];
-                    targetStack = [];
-                }
-                sourceStack[depth] = source;
-                targetStack[depth] = target;
-                depth++;
-                inferFromProperties(source, target);
-                inferFromSignatures(source, target, SignatureKind.Call);
-                inferFromSignatures(source, target, SignatureKind.Construct);
-                inferFromIndexTypes(source, target);
-                depth--;
-            }
-
-            function getTypeDifference(type: ObjectType, diff: ResolvedType): ResolvedType {
-                const members = createMap<Symbol>();
-                for (const prop of getPropertiesOfObjectType(type)) {
-                    if (!(prop.name in diff.members)) {
-                        members[prop.name] = prop;
+                        if (isDeeplyNestedGeneric(source, sourceStack, depth) && isDeeplyNestedGeneric(target, targetStack, depth)) {
+                            return;
+                        }
+                        const key = source.id + "," + target.id;
+                        if (visited[key]) {
+                            return;
+                        }
+                        visited[key] = true;
+                        if (depth === 0) {
+                            sourceStack = [];
+                            targetStack = [];
+                        }
+                        sourceStack[depth] = source;
+                        targetStack[depth] = target;
+                        depth++;
+                        inferFromProperties(source, target);
+                        inferFromSignatures(source, target, SignatureKind.Call);
+                        inferFromSignatures(source, target, SignatureKind.Construct);
+                        inferFromIndexTypes(source, target);
+                        depth--;
                     }
                 }
-                const stringIndexInfo = getIndexInfoOfType(diff, IndexKind.String) ? undefined : getIndexInfoOfType(type, IndexKind.String);
-                const numberIndexInfo = getIndexInfoOfType(diff, IndexKind.Number) ? undefined : getIndexInfoOfType(type, IndexKind.Number);
-                return createAnonymousType(type.symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
             }
 
             function inferFromProperties(source: Type, target: Type) {

From 62c186872d986dabf770dc7877de0f1167537af0 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 19 Oct 2016 13:14:20 -0700
Subject: [PATCH 059/224] Update inference test for spread types

---
 .../reference/objectSpreadInference.js        |  80 +-------
 .../reference/objectSpreadInference.symbols   | 147 +--------------
 .../reference/objectSpreadInference.types     | 178 +-----------------
 .../types/spread/objectSpreadInference.ts     |  46 +----
 4 files changed, 19 insertions(+), 432 deletions(-)

diff --git a/tests/baselines/reference/objectSpreadInference.js b/tests/baselines/reference/objectSpreadInference.js
index 06b17cfa1f948..77930e565118e 100644
--- a/tests/baselines/reference/objectSpreadInference.js
+++ b/tests/baselines/reference/objectSpreadInference.js
@@ -12,52 +12,12 @@ function generic<W, X, Y>(w: W, x: X, y: Y) {
 }
 let b: { b: number };
 let c: { c: number };
-// should infer { t: {}, u: { b: number, c: number }, v: number }
+// can only infer { t: {}, u: {}, v: {} }
 let i1 = infer({ ...b, ...c, a: 12 });
-// should infer { t: { a: number, b: number, c: number }, u: {}, v: {} }
+// can only infer { t: {}, u: {}, v: {} }
 let i2 = infer2({ ...b, ...c, a: 12 });
-// should infer { t: {}, u: {}, v: {} }
+// can only infer { t: {}, u: {}, v: {} }
 let i3 = generic(b, c, { a: 12 });
-
-interface Preserved {
-    kind: 0 | 1 | 2 | 3;
-}
-class C implements Preserved {
-    kind: 0 = 0;
-    a = 1;
-    method() { return "C"; }
-}
-declare function revive<T extends Preserved>(t: { ...T }): T;
-function genericRevive<U extends Preserved>(u: U) {
-    let us: { ...U };
-    return revive(us);
-}
-// result should not have `method`
-let result = revive({ a: 12, kind: 0 });
-// result2 should be of type C and have `method`
-let result2 = revive<C>({ a: 12, kind: 0 });
-
-declare function destructureRevive<T extends Preserved>(t: { ...T, a: number }): T;
-function genericDestructureRevive<U extends Preserved & { a: number }>(u: U) {
-    let us: { ...U };
-    return destructureRevive(us);
-}
-// result3 is just `Preserved` because `a` and `method` both get removed
-let result3 = destructureRevive({ a: 12, kind: 0 });
-// result4 is still C -- a is not removed -- because we specified the argument explicitly
-let result4 = destructureRevive<C>({ a: 12, kind: 0 });
-result4.method();
-result4.a;
-
-declare function removeIndexSignature<T>(t: { ...T, a: number, [s: string]: number, [n: number]: number }): T;
-interface I {
-    a: number;
-    b: number;
-    [s: string]: number;
-    [n: number]: number;
-}
-let i: I;
-let result5 = removeIndexSignature(i);
 
 
 //// [objectSpreadInference.js]
@@ -75,37 +35,9 @@ function generic(w, x, y) {
 }
 var b;
 var c;
-// should infer { t: {}, u: { b: number, c: number }, v: number }
+// can only infer { t: {}, u: {}, v: {} }
 var i1 = infer(__assign({}, b, c, { a: 12 }));
-// should infer { t: { a: number, b: number, c: number }, u: {}, v: {} }
+// can only infer { t: {}, u: {}, v: {} }
 var i2 = infer2(__assign({}, b, c, { a: 12 }));
-// should infer { t: {}, u: {}, v: {} }
+// can only infer { t: {}, u: {}, v: {} }
 var i3 = generic(b, c, { a: 12 });
-var C = (function () {
-    function C() {
-        this.kind = 0;
-        this.a = 1;
-    }
-    C.prototype.method = function () { return "C"; };
-    return C;
-}());
-function genericRevive(u) {
-    var us;
-    return revive(us);
-}
-// result should not have `method`
-var result = revive({ a: 12, kind: 0 });
-// result2 should be of type C and have `method`
-var result2 = revive({ a: 12, kind: 0 });
-function genericDestructureRevive(u) {
-    var us;
-    return destructureRevive(us);
-}
-// result3 is just `Preserved` because `a` and `method` both get removed
-var result3 = destructureRevive({ a: 12, kind: 0 });
-// result4 is still C -- a is not removed -- because we specified the argument explicitly
-var result4 = destructureRevive({ a: 12, kind: 0 });
-result4.method();
-result4.a;
-var i;
-var result5 = removeIndexSignature(i);
diff --git a/tests/baselines/reference/objectSpreadInference.symbols b/tests/baselines/reference/objectSpreadInference.symbols
index f03cd6b44e11a..ddecc4d7e5d3f 100644
--- a/tests/baselines/reference/objectSpreadInference.symbols
+++ b/tests/baselines/reference/objectSpreadInference.symbols
@@ -78,19 +78,19 @@ let c: { c: number };
 >c : Symbol(c, Decl(objectSpreadInference.ts, 12, 3))
 >c : Symbol(c, Decl(objectSpreadInference.ts, 12, 8))
 
-// should infer { t: {}, u: { b: number, c: number }, v: number }
+// can only infer { t: {}, u: {}, v: {} }
 let i1 = infer({ ...b, ...c, a: 12 });
 >i1 : Symbol(i1, Decl(objectSpreadInference.ts, 14, 3))
 >infer : Symbol(infer, Decl(objectSpreadInference.ts, 4, 1))
 >a : Symbol(a, Decl(objectSpreadInference.ts, 14, 28))
 
-// should infer { t: { a: number, b: number, c: number }, u: {}, v: {} }
+// can only infer { t: {}, u: {}, v: {} }
 let i2 = infer2({ ...b, ...c, a: 12 });
 >i2 : Symbol(i2, Decl(objectSpreadInference.ts, 16, 3))
 >infer2 : Symbol(infer2, Decl(objectSpreadInference.ts, 5, 79))
 >a : Symbol(a, Decl(objectSpreadInference.ts, 16, 29))
 
-// should infer { t: {}, u: {}, v: {} }
+// can only infer { t: {}, u: {}, v: {} }
 let i3 = generic(b, c, { a: 12 });
 >i3 : Symbol(i3, Decl(objectSpreadInference.ts, 18, 3))
 >generic : Symbol(generic, Decl(objectSpreadInference.ts, 6, 80))
@@ -98,144 +98,3 @@ let i3 = generic(b, c, { a: 12 });
 >c : Symbol(c, Decl(objectSpreadInference.ts, 12, 3))
 >a : Symbol(a, Decl(objectSpreadInference.ts, 18, 24))
 
-interface Preserved {
->Preserved : Symbol(Preserved, Decl(objectSpreadInference.ts, 18, 34))
-
-    kind: 0 | 1 | 2 | 3;
->kind : Symbol(Preserved.kind, Decl(objectSpreadInference.ts, 20, 21))
-}
-class C implements Preserved {
->C : Symbol(C, Decl(objectSpreadInference.ts, 22, 1))
->Preserved : Symbol(Preserved, Decl(objectSpreadInference.ts, 18, 34))
-
-    kind: 0 = 0;
->kind : Symbol(C.kind, Decl(objectSpreadInference.ts, 23, 30))
-
-    a = 1;
->a : Symbol(C.a, Decl(objectSpreadInference.ts, 24, 16))
-
-    method() { return "C"; }
->method : Symbol(C.method, Decl(objectSpreadInference.ts, 25, 10))
-}
-declare function revive<T extends Preserved>(t: { ...T }): T;
->revive : Symbol(revive, Decl(objectSpreadInference.ts, 27, 1))
->T : Symbol(T, Decl(objectSpreadInference.ts, 28, 24))
->Preserved : Symbol(Preserved, Decl(objectSpreadInference.ts, 18, 34))
->t : Symbol(t, Decl(objectSpreadInference.ts, 28, 45))
->T : Symbol(T, Decl(objectSpreadInference.ts, 28, 24))
->T : Symbol(T, Decl(objectSpreadInference.ts, 28, 24))
-
-function genericRevive<U extends Preserved>(u: U) {
->genericRevive : Symbol(genericRevive, Decl(objectSpreadInference.ts, 28, 61))
->U : Symbol(U, Decl(objectSpreadInference.ts, 29, 23))
->Preserved : Symbol(Preserved, Decl(objectSpreadInference.ts, 18, 34))
->u : Symbol(u, Decl(objectSpreadInference.ts, 29, 44))
->U : Symbol(U, Decl(objectSpreadInference.ts, 29, 23))
-
-    let us: { ...U };
->us : Symbol(us, Decl(objectSpreadInference.ts, 30, 7))
->U : Symbol(U, Decl(objectSpreadInference.ts, 29, 23))
-
-    return revive(us);
->revive : Symbol(revive, Decl(objectSpreadInference.ts, 27, 1))
->us : Symbol(us, Decl(objectSpreadInference.ts, 30, 7))
-}
-// result should not have `method`
-let result = revive({ a: 12, kind: 0 });
->result : Symbol(result, Decl(objectSpreadInference.ts, 34, 3))
->revive : Symbol(revive, Decl(objectSpreadInference.ts, 27, 1))
->a : Symbol(a, Decl(objectSpreadInference.ts, 34, 21))
->kind : Symbol(kind, Decl(objectSpreadInference.ts, 34, 28))
-
-// result2 should be of type C and have `method`
-let result2 = revive<C>({ a: 12, kind: 0 });
->result2 : Symbol(result2, Decl(objectSpreadInference.ts, 36, 3))
->revive : Symbol(revive, Decl(objectSpreadInference.ts, 27, 1))
->C : Symbol(C, Decl(objectSpreadInference.ts, 22, 1))
->a : Symbol(a, Decl(objectSpreadInference.ts, 36, 25))
->kind : Symbol(kind, Decl(objectSpreadInference.ts, 36, 32))
-
-declare function destructureRevive<T extends Preserved>(t: { ...T, a: number }): T;
->destructureRevive : Symbol(destructureRevive, Decl(objectSpreadInference.ts, 36, 44))
->T : Symbol(T, Decl(objectSpreadInference.ts, 38, 35))
->Preserved : Symbol(Preserved, Decl(objectSpreadInference.ts, 18, 34))
->t : Symbol(t, Decl(objectSpreadInference.ts, 38, 56))
->T : Symbol(T, Decl(objectSpreadInference.ts, 38, 35))
->a : Symbol(a, Decl(objectSpreadInference.ts, 38, 66))
->T : Symbol(T, Decl(objectSpreadInference.ts, 38, 35))
-
-function genericDestructureRevive<U extends Preserved & { a: number }>(u: U) {
->genericDestructureRevive : Symbol(genericDestructureRevive, Decl(objectSpreadInference.ts, 38, 83))
->U : Symbol(U, Decl(objectSpreadInference.ts, 39, 34))
->Preserved : Symbol(Preserved, Decl(objectSpreadInference.ts, 18, 34))
->a : Symbol(a, Decl(objectSpreadInference.ts, 39, 57))
->u : Symbol(u, Decl(objectSpreadInference.ts, 39, 71))
->U : Symbol(U, Decl(objectSpreadInference.ts, 39, 34))
-
-    let us: { ...U };
->us : Symbol(us, Decl(objectSpreadInference.ts, 40, 7))
->U : Symbol(U, Decl(objectSpreadInference.ts, 39, 34))
-
-    return destructureRevive(us);
->destructureRevive : Symbol(destructureRevive, Decl(objectSpreadInference.ts, 36, 44))
->us : Symbol(us, Decl(objectSpreadInference.ts, 40, 7))
-}
-// result3 is just `Preserved` because `a` and `method` both get removed
-let result3 = destructureRevive({ a: 12, kind: 0 });
->result3 : Symbol(result3, Decl(objectSpreadInference.ts, 44, 3))
->destructureRevive : Symbol(destructureRevive, Decl(objectSpreadInference.ts, 36, 44))
->a : Symbol(a, Decl(objectSpreadInference.ts, 44, 33))
->kind : Symbol(kind, Decl(objectSpreadInference.ts, 44, 40))
-
-// result4 is still C -- a is not removed -- because we specified the argument explicitly
-let result4 = destructureRevive<C>({ a: 12, kind: 0 });
->result4 : Symbol(result4, Decl(objectSpreadInference.ts, 46, 3))
->destructureRevive : Symbol(destructureRevive, Decl(objectSpreadInference.ts, 36, 44))
->C : Symbol(C, Decl(objectSpreadInference.ts, 22, 1))
->a : Symbol(a, Decl(objectSpreadInference.ts, 46, 36))
->kind : Symbol(kind, Decl(objectSpreadInference.ts, 46, 43))
-
-result4.method();
->result4.method : Symbol(C.method, Decl(objectSpreadInference.ts, 25, 10))
->result4 : Symbol(result4, Decl(objectSpreadInference.ts, 46, 3))
->method : Symbol(C.method, Decl(objectSpreadInference.ts, 25, 10))
-
-result4.a;
->result4.a : Symbol(C.a, Decl(objectSpreadInference.ts, 24, 16))
->result4 : Symbol(result4, Decl(objectSpreadInference.ts, 46, 3))
->a : Symbol(C.a, Decl(objectSpreadInference.ts, 24, 16))
-
-declare function removeIndexSignature<T>(t: { ...T, a: number, [s: string]: number, [n: number]: number }): T;
->removeIndexSignature : Symbol(removeIndexSignature, Decl(objectSpreadInference.ts, 48, 10))
->T : Symbol(T, Decl(objectSpreadInference.ts, 50, 38))
->t : Symbol(t, Decl(objectSpreadInference.ts, 50, 41))
->T : Symbol(T, Decl(objectSpreadInference.ts, 50, 38))
->a : Symbol(a, Decl(objectSpreadInference.ts, 50, 51))
->s : Symbol(s, Decl(objectSpreadInference.ts, 50, 64))
->n : Symbol(n, Decl(objectSpreadInference.ts, 50, 85))
->T : Symbol(T, Decl(objectSpreadInference.ts, 50, 38))
-
-interface I {
->I : Symbol(I, Decl(objectSpreadInference.ts, 50, 110))
-
-    a: number;
->a : Symbol(I.a, Decl(objectSpreadInference.ts, 51, 13))
-
-    b: number;
->b : Symbol(I.b, Decl(objectSpreadInference.ts, 52, 14))
-
-    [s: string]: number;
->s : Symbol(s, Decl(objectSpreadInference.ts, 54, 5))
-
-    [n: number]: number;
->n : Symbol(n, Decl(objectSpreadInference.ts, 55, 5))
-}
-let i: I;
->i : Symbol(i, Decl(objectSpreadInference.ts, 57, 3))
->I : Symbol(I, Decl(objectSpreadInference.ts, 50, 110))
-
-let result5 = removeIndexSignature(i);
->result5 : Symbol(result5, Decl(objectSpreadInference.ts, 58, 3))
->removeIndexSignature : Symbol(removeIndexSignature, Decl(objectSpreadInference.ts, 48, 10))
->i : Symbol(i, Decl(objectSpreadInference.ts, 57, 3))
-
diff --git a/tests/baselines/reference/objectSpreadInference.types b/tests/baselines/reference/objectSpreadInference.types
index 55303119932e1..3e71e29b83c48 100644
--- a/tests/baselines/reference/objectSpreadInference.types
+++ b/tests/baselines/reference/objectSpreadInference.types
@@ -83,10 +83,10 @@ let c: { c: number };
 >c : { c: number; }
 >c : number
 
-// should infer { t: {}, u: { b: number, c: number }, v: number }
+// can only infer { t: {}, u: {}, v: {} }
 let i1 = infer({ ...b, ...c, a: 12 });
->i1 : { t: {}; u: { c: number; b: number; }; v: number; }
->infer({ ...b, ...c, a: 12 }) : { t: {}; u: { c: number; b: number; }; v: number; }
+>i1 : { t: {}; u: {}; v: {}; }
+>infer({ ...b, ...c, a: 12 }) : { t: {}; u: {}; v: {}; }
 >infer : <T, U, V>(tuv: { ...T; ...U; a: V; }) => { t: T; u: U; v: V; }
 >{ ...b, ...c, a: 12 } : { a: number; c: number; b: number; }
 >b : any
@@ -94,10 +94,10 @@ let i1 = infer({ ...b, ...c, a: 12 });
 >a : number
 >12 : 12
 
-// should infer { t: { a: number, b: number, c: number }, u: {}, v: {} }
+// can only infer { t: {}, u: {}, v: {} }
 let i2 = infer2({ ...b, ...c, a: 12 });
->i2 : { t: { a: number; c: number; b: number; }; u: {}; v: {}; }
->infer2({ ...b, ...c, a: 12 }) : { t: { a: number; c: number; b: number; }; u: {}; v: {}; }
+>i2 : { t: {}; u: {}; v: {}; }
+>infer2({ ...b, ...c, a: 12 }) : { t: {}; u: {}; v: {}; }
 >infer2 : <T, U, V>(utv: { ...U; a: V; ...T }) => { t: T; u: U; v: V; }
 >{ ...b, ...c, a: 12 } : { a: number; c: number; b: number; }
 >b : any
@@ -105,7 +105,7 @@ let i2 = infer2({ ...b, ...c, a: 12 });
 >a : number
 >12 : 12
 
-// should infer { t: {}, u: {}, v: {} }
+// can only infer { t: {}, u: {}, v: {} }
 let i3 = generic(b, c, { a: 12 });
 >i3 : { t: {}; u: {}; v: {}; }
 >generic(b, c, { a: 12 }) : { t: {}; u: {}; v: {}; }
@@ -116,167 +116,3 @@ let i3 = generic(b, c, { a: 12 });
 >a : number
 >12 : 12
 
-interface Preserved {
->Preserved : Preserved
-
-    kind: 0 | 1 | 2 | 3;
->kind : 0 | 1 | 2 | 3
-}
-class C implements Preserved {
->C : C
->Preserved : Preserved
-
-    kind: 0 = 0;
->kind : 0
->0 : 0
-
-    a = 1;
->a : number
->1 : 1
-
-    method() { return "C"; }
->method : () => string
->"C" : "C"
-}
-declare function revive<T extends Preserved>(t: { ...T }): T;
->revive : <T extends Preserved>(t: { ...T }) => T
->T : T
->Preserved : Preserved
->t : { ...T }
->T : T
->T : T
-
-function genericRevive<U extends Preserved>(u: U) {
->genericRevive : <U extends Preserved>(u: U) => U
->U : U
->Preserved : Preserved
->u : U
->U : U
-
-    let us: { ...U };
->us : { ...U }
->U : U
-
-    return revive(us);
->revive(us) : U
->revive : <T extends Preserved>(t: { ...T }) => T
->us : { ...U }
-}
-// result should not have `method`
-let result = revive({ a: 12, kind: 0 });
->result : { a: number; kind: 0; }
->revive({ a: 12, kind: 0 }) : { a: number; kind: 0; }
->revive : <T extends Preserved>(t: { ...T }) => T
->{ a: 12, kind: 0 } : { a: number; kind: 0; }
->a : number
->12 : 12
->kind : number
->0 : 0
-
-// result2 should be of type C and have `method`
-let result2 = revive<C>({ a: 12, kind: 0 });
->result2 : C
->revive<C>({ a: 12, kind: 0 }) : C
->revive : <T extends Preserved>(t: { ...T }) => T
->C : C
->{ a: 12, kind: 0 } : { a: number; kind: 0; }
->a : number
->12 : 12
->kind : number
->0 : 0
-
-declare function destructureRevive<T extends Preserved>(t: { ...T, a: number }): T;
->destructureRevive : <T extends Preserved>(t: { ...T; a: number; }) => T
->T : T
->Preserved : Preserved
->t : { ...T; a: number; }
->T : T
->a : number
->T : T
-
-function genericDestructureRevive<U extends Preserved & { a: number }>(u: U) {
->genericDestructureRevive : <U extends Preserved & { a: number; }>(u: U) => Preserved
->U : U
->Preserved : Preserved
->a : number
->u : U
->U : U
-
-    let us: { ...U };
->us : { ...U }
->U : U
-
-    return destructureRevive(us);
->destructureRevive(us) : Preserved
->destructureRevive : <T extends Preserved>(t: { ...T; a: number; }) => T
->us : { ...U }
-}
-// result3 is just `Preserved` because `a` and `method` both get removed
-let result3 = destructureRevive({ a: 12, kind: 0 });
->result3 : { kind: 0; }
->destructureRevive({ a: 12, kind: 0 }) : { kind: 0; }
->destructureRevive : <T extends Preserved>(t: { ...T; a: number; }) => T
->{ a: 12, kind: 0 } : { a: number; kind: 0; }
->a : number
->12 : 12
->kind : number
->0 : 0
-
-// result4 is still C -- a is not removed -- because we specified the argument explicitly
-let result4 = destructureRevive<C>({ a: 12, kind: 0 });
->result4 : C
->destructureRevive<C>({ a: 12, kind: 0 }) : C
->destructureRevive : <T extends Preserved>(t: { ...T; a: number; }) => T
->C : C
->{ a: 12, kind: 0 } : { a: number; kind: 0; }
->a : number
->12 : 12
->kind : number
->0 : 0
-
-result4.method();
->result4.method() : string
->result4.method : () => string
->result4 : C
->method : () => string
-
-result4.a;
->result4.a : number
->result4 : C
->a : number
-
-declare function removeIndexSignature<T>(t: { ...T, a: number, [s: string]: number, [n: number]: number }): T;
->removeIndexSignature : <T>(t: { ...T; [s: string]: number; [n: number]: number; a: number; }) => T
->T : T
->t : { ...T; [s: string]: number; [n: number]: number; a: number; }
->T : T
->a : number
->s : string
->n : number
->T : T
-
-interface I {
->I : I
-
-    a: number;
->a : number
-
-    b: number;
->b : number
-
-    [s: string]: number;
->s : string
-
-    [n: number]: number;
->n : number
-}
-let i: I;
->i : I
->I : I
-
-let result5 = removeIndexSignature(i);
->result5 : { b: number; }
->removeIndexSignature(i) : { b: number; }
->removeIndexSignature : <T>(t: { ...T; [s: string]: number; [n: number]: number; a: number; }) => T
->i : I
-
diff --git a/tests/cases/conformance/types/spread/objectSpreadInference.ts b/tests/cases/conformance/types/spread/objectSpreadInference.ts
index 1984193241988..9608f0a16cb95 100644
--- a/tests/cases/conformance/types/spread/objectSpreadInference.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadInference.ts
@@ -11,49 +11,9 @@ function generic<W, X, Y>(w: W, x: X, y: Y) {
 }
 let b: { b: number };
 let c: { c: number };
-// should infer { t: {}, u: { b: number, c: number }, v: number }
+// can only infer { t: {}, u: {}, v: {} }
 let i1 = infer({ ...b, ...c, a: 12 });
-// should infer { t: { a: number, b: number, c: number }, u: {}, v: {} }
+// can only infer { t: {}, u: {}, v: {} }
 let i2 = infer2({ ...b, ...c, a: 12 });
-// should infer { t: {}, u: {}, v: {} }
+// can only infer { t: {}, u: {}, v: {} }
 let i3 = generic(b, c, { a: 12 });
-
-interface Preserved {
-    kind: 0 | 1 | 2 | 3;
-}
-class C implements Preserved {
-    kind: 0 = 0;
-    a = 1;
-    method() { return "C"; }
-}
-declare function revive<T extends Preserved>(t: { ...T }): T;
-function genericRevive<U extends Preserved>(u: U) {
-    let us: { ...U };
-    return revive(us);
-}
-// result should not have `method`
-let result = revive({ a: 12, kind: 0 });
-// result2 should be of type C and have `method`
-let result2 = revive<C>({ a: 12, kind: 0 });
-
-declare function destructureRevive<T extends Preserved>(t: { ...T, a: number }): T;
-function genericDestructureRevive<U extends Preserved & { a: number }>(u: U) {
-    let us: { ...U };
-    return destructureRevive(us);
-}
-// result3 is just `Preserved` because `a` and `method` both get removed
-let result3 = destructureRevive({ a: 12, kind: 0 });
-// result4 is still C -- a is not removed -- because we specified the argument explicitly
-let result4 = destructureRevive<C>({ a: 12, kind: 0 });
-result4.method();
-result4.a;
-
-declare function removeIndexSignature<T>(t: { ...T, a: number, [s: string]: number, [n: number]: number }): T;
-interface I {
-    a: number;
-    b: number;
-    [s: string]: number;
-    [n: number]: number;
-}
-let i: I;
-let result5 = removeIndexSignature(i);

From a90905358d5baf6224392bac9ba62394e102d07e Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 19 Oct 2016 15:04:30 -0700
Subject: [PATCH 060/224] Make spread assignability and apparent type stricter

Assignability now does not allow properties to the left of a type
parameter.
Apparent type now only returns the apparent type of the right-most
spread member.
---
 src/compiler/checker.ts | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 8e196da87de29..e3651f6cf3014 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4515,7 +4515,7 @@ namespace ts {
         }
 
         function getApparentTypeOfSpread(type: SpreadType) {
-            return getSpreadType([getApparentType(type.left), getApparentType(type.right)], type.symbol);
+            return getApparentType(type.right);
         }
 
         /**
@@ -5837,9 +5837,8 @@ namespace ts {
                 left.flags & TypeFlags.Spread &&
                 (left as SpreadType).right.flags & TypeFlags.ObjectType) {
                 // simplify two adjacent object types: T ... { x } ... { y } becomes T ... { x, y }
-                // Note: left.left is always a spread type. Can we use this fact to avoid calling getSpreadType again?
-                return getSpreadType([getSpreadType([right, (left as SpreadType).right], symbol, aliasSymbol, aliasTypeArguments),
-                                      (left as SpreadType).left], symbol, aliasSymbol, aliasTypeArguments);
+                const simplified = getSpreadType([right, (left as SpreadType).right], symbol, aliasSymbol, aliasTypeArguments);
+                return getSpreadType([(left as SpreadType).left, simplified], symbol, aliasSymbol, aliasTypeArguments);
             }
             if (left.flags & TypeFlags.Intersection) {
                 const spreads = map((left as IntersectionType).types,
@@ -6872,7 +6871,7 @@ namespace ts {
 
                 if (source.flags & TypeFlags.Spread && target.flags & TypeFlags.Spread) {
                     // you only see this for spreads with type parameters
-                    if (!(spreadTypeRelatedTo(source as SpreadType, target as SpreadType))) {
+                    if (!(spreadTypeRelatedTo(source as SpreadType, target as SpreadType, /*atRightEdge*/ true))) {
                         if (reportErrors) {
                             reportRelationError(headMessage, source, target);
                         }
@@ -6945,13 +6944,14 @@ namespace ts {
                 return Ternary.False;
             }
 
-            function spreadTypeRelatedTo(source: SpreadType, target: SpreadType): boolean {
+            function spreadTypeRelatedTo(source: SpreadType, target: SpreadType, atRightEdge?: boolean): boolean {
                 // If the right side of a spread type is ObjectType, then the left side must be a Spread.
                 // Structural compatibility of the spreads' object types are checked separately in isRelatedTo,
                 // so just skip them for now.
                 if (source.right.flags & TypeFlags.ObjectType || target.right.flags & TypeFlags.ObjectType) {
-                    return spreadTypeRelatedTo(source.right.flags & TypeFlags.ObjectType ? source.left as SpreadType : source,
-                                               target.right.flags & TypeFlags.ObjectType ? target.left as SpreadType : target);
+                    return atRightEdge &&
+                        spreadTypeRelatedTo(source.right.flags & TypeFlags.ObjectType ? source.left as SpreadType : source,
+                                            target.right.flags & TypeFlags.ObjectType ? target.left as SpreadType : target);
                 }
                 // If both right sides are type parameters, then they must be identical for the spread types to be related.
                 // It also means that the left sides are either spread types or object types.
@@ -6964,9 +6964,9 @@ namespace ts {
                     // If the left sides are both spread types, then recursively check them.
                     return spreadTypeRelatedTo(source.left as SpreadType, target.left as SpreadType);
                 }
-                // If the left sides are both object types, then isRelatedTo will check the structural compatibility next.
-                // Otherwise, one side has more type parameters than the other and the spread types are not related.
-                return !!(source.left.flags & TypeFlags.ObjectType && target.left.flags & TypeFlags.ObjectType);
+                // If the left sides are both object types, then we should be at the end and both should be emptyObjectType.
+                // If not, we can't know what properties might have been overwritten, so fail.
+                return source.left === emptyObjectType && target.left === emptyObjectType;
             }
 
             function isIdenticalTo(source: Type, target: Type): Ternary {

From ad10ec56c1214ee5a52f1de3f2dce00f0ca3d025 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 19 Oct 2016 15:05:42 -0700
Subject: [PATCH 061/224] Update tests w/spread assignability+apparent type

---
 tests/baselines/reference/objectSpread.js     |  8 +-
 .../baselines/reference/objectSpread.symbols  | 16 +--
 tests/baselines/reference/objectSpread.types  | 40 ++++----
 .../reference/objectSpreadGeneric.errors.txt  | 49 ++++++----
 .../reference/objectSpreadGeneric.js          | 36 ++++---
 .../reference/objectSpreadIntersection.js     | 32 +++---
 .../objectSpreadIntersection.symbols          | 70 ++++++-------
 .../reference/objectSpreadIntersection.types  | 98 +++++++++----------
 .../baselines/reference/objectSpreadUnion.js  | 16 +--
 .../reference/objectSpreadUnion.symbols       | 34 +++----
 .../reference/objectSpreadUnion.types         | 48 ++++-----
 .../conformance/types/spread/objectSpread.ts  |  6 +-
 .../types/spread/objectSpreadGeneric.ts       | 18 ++--
 .../types/spread/objectSpreadIntersection.ts  | 24 ++---
 .../types/spread/objectSpreadUnion.ts         | 12 +--
 15 files changed, 262 insertions(+), 245 deletions(-)

diff --git a/tests/baselines/reference/objectSpread.js b/tests/baselines/reference/objectSpread.js
index efb73bcb35399..359284f9c6c51 100644
--- a/tests/baselines/reference/objectSpread.js
+++ b/tests/baselines/reference/objectSpread.js
@@ -83,8 +83,8 @@ let a = 12;
 let shortCutted: { a: number, b: string } = { ...o, a }
 
 // generics
-function f<T, U>(t: T, u: U): { id: string, ...T, ...U } {
-    return { id: 'id', ...t, ...u };
+function f<T, U>(t: T, u: U): { ...T, ...U, id: string } {
+    return { ...t, ...u, id: 'id' };
 }
 let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
     f({ a: 1, b: 'yes' }, { c: 'no', d: false })
@@ -92,7 +92,7 @@ let overlap: { id: string, a: number, b: string } =
     f({ a: 1 }, { a: 2, b: 'extra' })
 let overlapConflict: { id:string, a: string } =
     f({ a: 1 }, { a: 'mismatch' })
-let overwriteId: { id: boolean, a: number, c: number, d: string } =
+let overwriteId: { id: string, a: number, c: number, d: string } =
     f({ a: 1, id: true }, { c: 1, d: 'no' })
 
 class D { m() { }; q = 2; }
@@ -172,7 +172,7 @@ var a = 12;
 var shortCutted = __assign({}, o, { a: a });
 // generics
 function f(t, u) {
-    return __assign({ id: 'id' }, t, u);
+    return __assign({}, t, u, { id: 'id' });
 }
 var exclusive = f({ a: 1, b: 'yes' }, { c: 'no', d: false });
 var overlap = f({ a: 1 }, { a: 2, b: 'extra' });
diff --git a/tests/baselines/reference/objectSpread.symbols b/tests/baselines/reference/objectSpread.symbols
index d23016ddb1e15..fb7a1e22b33f3 100644
--- a/tests/baselines/reference/objectSpread.symbols
+++ b/tests/baselines/reference/objectSpread.symbols
@@ -290,7 +290,7 @@ let shortCutted: { a: number, b: string } = { ...o, a }
 >a : Symbol(a, Decl(objectSpread.ts, 81, 51))
 
 // generics
-function f<T, U>(t: T, u: U): { id: string, ...T, ...U } {
+function f<T, U>(t: T, u: U): { ...T, ...U, id: string } {
 >f : Symbol(f, Decl(objectSpread.ts, 81, 55))
 >T : Symbol(T, Decl(objectSpread.ts, 84, 11))
 >U : Symbol(U, Decl(objectSpread.ts, 84, 13))
@@ -298,12 +298,12 @@ function f<T, U>(t: T, u: U): { id: string, ...T, ...U } {
 >T : Symbol(T, Decl(objectSpread.ts, 84, 11))
 >u : Symbol(u, Decl(objectSpread.ts, 84, 22))
 >U : Symbol(U, Decl(objectSpread.ts, 84, 13))
->id : Symbol(id, Decl(objectSpread.ts, 84, 31))
 >T : Symbol(T, Decl(objectSpread.ts, 84, 11))
 >U : Symbol(U, Decl(objectSpread.ts, 84, 13))
+>id : Symbol(id, Decl(objectSpread.ts, 84, 43))
 
-    return { id: 'id', ...t, ...u };
->id : Symbol(id, Decl(objectSpread.ts, 85, 12))
+    return { ...t, ...u, id: 'id' };
+>id : Symbol(id, Decl(objectSpread.ts, 85, 24))
 }
 let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
 >exclusive : Symbol(exclusive, Decl(objectSpread.ts, 87, 3))
@@ -342,12 +342,12 @@ let overlapConflict: { id:string, a: string } =
 >a : Symbol(a, Decl(objectSpread.ts, 92, 7))
 >a : Symbol(a, Decl(objectSpread.ts, 92, 17))
 
-let overwriteId: { id: boolean, a: number, c: number, d: string } =
+let overwriteId: { id: string, a: number, c: number, d: string } =
 >overwriteId : Symbol(overwriteId, Decl(objectSpread.ts, 93, 3))
 >id : Symbol(id, Decl(objectSpread.ts, 93, 18))
->a : Symbol(a, Decl(objectSpread.ts, 93, 31))
->c : Symbol(c, Decl(objectSpread.ts, 93, 42))
->d : Symbol(d, Decl(objectSpread.ts, 93, 53))
+>a : Symbol(a, Decl(objectSpread.ts, 93, 30))
+>c : Symbol(c, Decl(objectSpread.ts, 93, 41))
+>d : Symbol(d, Decl(objectSpread.ts, 93, 52))
 
     f({ a: 1, id: true }, { c: 1, d: 'no' })
 >f : Symbol(f, Decl(objectSpread.ts, 81, 55))
diff --git a/tests/baselines/reference/objectSpread.types b/tests/baselines/reference/objectSpread.types
index efab098fd6e22..b6fcb9150bf3a 100644
--- a/tests/baselines/reference/objectSpread.types
+++ b/tests/baselines/reference/objectSpread.types
@@ -423,24 +423,24 @@ let shortCutted: { a: number, b: string } = { ...o, a }
 >a : number
 
 // generics
-function f<T, U>(t: T, u: U): { id: string, ...T, ...U } {
->f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
+function f<T, U>(t: T, u: U): { ...T, ...U, id: string } {
+>f : <T, U>(t: T, u: U) => { ...T; ...U; id: string; }
 >T : T
 >U : U
 >t : T
 >T : T
 >u : U
 >U : U
->id : string
 >T : T
 >U : U
-
-    return { id: 'id', ...t, ...u };
->{ id: 'id', ...t, ...u } : { id: string; ...T; ...U }
 >id : string
->'id' : "id"
+
+    return { ...t, ...u, id: 'id' };
+>{ ...t, ...u, id: 'id' } : { ...T; ...U; id: string; }
 >t : any
 >u : any
+>id : string
+>'id' : "id"
 }
 let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
 >exclusive : { id: string; a: number; b: string; c: string; d: boolean; }
@@ -451,8 +451,8 @@ let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
 >d : boolean
 
     f({ a: 1, b: 'yes' }, { c: 'no', d: false })
->f({ a: 1, b: 'yes' }, { c: 'no', d: false }) : { c: string; d: boolean; a: number; b: string; id: string; }
->f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
+>f({ a: 1, b: 'yes' }, { c: 'no', d: false }) : { id: string; c: string; d: boolean; a: number; b: string; }
+>f : <T, U>(t: T, u: U) => { ...T; ...U; id: string; }
 >{ a: 1, b: 'yes' } : { a: number; b: string; }
 >a : number
 >1 : 1
@@ -471,8 +471,8 @@ let overlap: { id: string, a: number, b: string } =
 >b : string
 
     f({ a: 1 }, { a: 2, b: 'extra' })
->f({ a: 1 }, { a: 2, b: 'extra' }) : { a: number; b: string; id: string; }
->f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
+>f({ a: 1 }, { a: 2, b: 'extra' }) : { id: string; a: number; b: string; }
+>f : <T, U>(t: T, u: U) => { ...T; ...U; id: string; }
 >{ a: 1 } : { a: number; }
 >a : number
 >1 : 1
@@ -488,8 +488,8 @@ let overlapConflict: { id:string, a: string } =
 >a : string
 
     f({ a: 1 }, { a: 'mismatch' })
->f({ a: 1 }, { a: 'mismatch' }) : { a: string; id: string; }
->f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
+>f({ a: 1 }, { a: 'mismatch' }) : { id: string; a: string; }
+>f : <T, U>(t: T, u: U) => { ...T; ...U; id: string; }
 >{ a: 1 } : { a: number; }
 >a : number
 >1 : 1
@@ -497,16 +497,16 @@ let overlapConflict: { id:string, a: string } =
 >a : string
 >'mismatch' : "mismatch"
 
-let overwriteId: { id: boolean, a: number, c: number, d: string } =
->overwriteId : { id: boolean; a: number; c: number; d: string; }
->id : boolean
+let overwriteId: { id: string, a: number, c: number, d: string } =
+>overwriteId : { id: string; a: number; c: number; d: string; }
+>id : string
 >a : number
 >c : number
 >d : string
 
     f({ a: 1, id: true }, { c: 1, d: 'no' })
->f({ a: 1, id: true }, { c: 1, d: 'no' }) : { c: number; d: string; a: number; id: boolean; }
->f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
+>f({ a: 1, id: true }, { c: 1, d: 'no' }) : { id: string; c: number; d: string; a: number; }
+>f : <T, U>(t: T, u: U) => { ...T; ...U; id: string; }
 >{ a: 1, id: true } : { a: number; id: true; }
 >a : number
 >1 : 1
@@ -531,8 +531,8 @@ let classesAreWrong: { id: string, ...C, ...D } =
 >D : D
 
     f(new C(), new D())
->f(new C(), new D()) : { q: number; p: number; id: string; }
->f : <T, U>(t: T, u: U) => { id: string; ...T; ...U }
+>f(new C(), new D()) : { id: string; q: number; p: number; }
+>f : <T, U>(t: T, u: U) => { ...T; ...U; id: string; }
 >new C() : C
 >C : typeof C
 >new D() : D
diff --git a/tests/baselines/reference/objectSpreadGeneric.errors.txt b/tests/baselines/reference/objectSpreadGeneric.errors.txt
index 6e55040f22391..8b9c767f6de3d 100644
--- a/tests/baselines/reference/objectSpreadGeneric.errors.txt
+++ b/tests/baselines/reference/objectSpreadGeneric.errors.txt
@@ -4,17 +4,19 @@ tests/cases/conformance/types/spread/objectSpreadGeneric.ts(11,11): error TS2322
 tests/cases/conformance/types/spread/objectSpreadGeneric.ts(12,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...V }'.
 tests/cases/conformance/types/spread/objectSpreadGeneric.ts(13,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...V }'.
 tests/cases/conformance/types/spread/objectSpreadGeneric.ts(14,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...U }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(16,11): error TS2322: Type '{ first: string; ...T; ...U }' is not assignable to type '{ first: string; ...T; ...U }'.
 tests/cases/conformance/types/spread/objectSpreadGeneric.ts(19,11): error TS2322: Type '{}' is not assignable to type '{ ...T; ...U }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(32,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; second: string; ...T; third: string; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(40,11): error TS2322: Type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-  Property 'first' is missing in type '{ third: string; second: string; firrrrrrst: string; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(42,11): error TS2322: Type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-  Property 'second' is missing in type '{ third: string; ssssssssecond: string; first: string; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(44,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-  Property 'third' is missing in type '{ thirrrrrrrd: string; second: string; first: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(26,11): error TS2322: Type '{ sn?: boolean; ...T; sn?: string | number; }' is not assignable to type '{ ...T; sn?: string | number | boolean; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(32,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(34,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; second: string; ...T; third: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(36,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; secondsecond: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; secondsecond: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(38,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; secondsecond: string; }' is not assignable to type '{ first: string; second: string; secondsecond: string; third: string; ...T; ...U }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(42,11): error TS2322: Type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(44,11): error TS2322: Type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(46,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
 
 
-==== tests/cases/conformance/types/spread/objectSpreadGeneric.ts (11 errors) ====
+==== tests/cases/conformance/types/spread/objectSpreadGeneric.ts (16 errors) ====
     function f<T, U, V>(t: T, u: U, v: V): void {
         let o: { ...T, ...U, ...V };
         let uus: { ...U, ...U};
@@ -42,48 +44,57 @@ tests/cases/conformance/types/spread/objectSpreadGeneric.ts(44,11): error TS2322
               ~~~~~~~~
 !!! error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...U }'.
         const atEnd: { ...T, ...U, second: string } = { ...t, ...u, second: 'foo' }; // ok
-        const atBeginning: { first: string, ...T, ...U, } = { first: 'foo', ...t, ...u }; // ok
+        const atBeginning: { first: string, ...T, ...U, } = { first: 'foo', ...t, ...u }; // error, not assignable
+              ~~~~~~~~~~~
+!!! error TS2322: Type '{ first: string; ...T; ...U }' is not assignable to type '{ first: string; ...T; ...U }'.
     
         const emptyTarget: { } = { ...t, ...u } // ok
         const emptySource: { ...T, ...U } = { }; // error, {} is not assignable to U (or T)
               ~~~~~~~~~~~
 !!! error TS2322: Type '{}' is not assignable to type '{ ...T; ...U }'.
     
+        // error, { sn?: boolean } ...T ... { sn?: number | string } is not assignable to
+        //        T ... { sn?: number | string | boolean }
         let optionalNumber: { sn?: number };
         let optionalString: { sn?: string };
         let optionalBoolean: { sn?: boolean };
         const unionCutoff: { ...T, sn?: number | string | boolean } =
-            { ...optionalBoolean, ...t, ...optionalString, ...optionalNumber } // ok
+              ~~~~~~~~~~~
+!!! error TS2322: Type '{ sn?: boolean; ...T; sn?: string | number; }' is not assignable to type '{ ...T; sn?: string | number | boolean; }'.
+            { ...optionalBoolean, ...t, ...optionalString, ...optionalNumber }
         unionCutoff.sn; // ok
         const optionalCutoff = { ...t, ...optionalNumber }; // ok
         optionalCutoff.sn; // ok
     
         const interspersed: { first: string, ...T, second: string, ...U, third: string } =
-            { first: '1', ...t, second: '2', ...u, third: '3' }; // ok
+              ~~~~~~~~~~~~
+!!! error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+            { first: '1', ...t, second: '2', ...u, third: '3' }; // error, not assignable
         const interspersedMissingU: { first: string, second: string, ...T, third: string } =
               ~~~~~~~~~~~~~~~~~~~~
 !!! error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; second: string; ...T; third: string; }'.
             { first: '1', ...t, second: '2', ...u, third: '3' }; // error, 'U' is missing
         const interspersedOrder1: { first: string, ...T, second: string, ...U, third: string, secondsecond: string } =
-            { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // ok
+              ~~~~~~~~~~~~~~~~~~
+!!! error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; secondsecond: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; secondsecond: string; }'.
+            { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // error, not assignable
         const interspersedOrder2: { first: string, second: string, secondsecond: string, third: string, ...T, ...U } =
-            { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // ok
+              ~~~~~~~~~~~~~~~~~~
+!!! error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; secondsecond: string; }' is not assignable to type '{ first: string; second: string; secondsecond: string; third: string; ...T; ...U }'.
+            { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // error, not assignable
     
     
         const mismatchFirst: { first: string, ...T, second: string, ...U, third: string } =
               ~~~~~~~~~~~~~
 !!! error TS2322: Type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-!!! error TS2322:   Property 'first' is missing in type '{ third: string; second: string; firrrrrrst: string; }'.
-            { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, 'first' not found
+            { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, not assignable
         const mismatchSecond: { first: string, ...T, second: string, ...U, third: string } =
               ~~~~~~~~~~~~~~
 !!! error TS2322: Type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-!!! error TS2322:   Property 'second' is missing in type '{ third: string; ssssssssecond: string; first: string; }'.
-            { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, 'second' not found
+            { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, not assignable
         const mismatchLast: { first: string, ...T, second: string, ...U, third: string } =
               ~~~~~~~~~~~~
 !!! error TS2322: Type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-!!! error TS2322:   Property 'third' is missing in type '{ thirrrrrrrd: string; second: string; first: string; }'.
-            { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, 'third' not found
+            { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, not assignable
     }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadGeneric.js b/tests/baselines/reference/objectSpreadGeneric.js
index 9414b9ef76e86..fa19e47df39e7 100644
--- a/tests/baselines/reference/objectSpreadGeneric.js
+++ b/tests/baselines/reference/objectSpreadGeneric.js
@@ -14,36 +14,38 @@ function f<T, U, V>(t: T, u: U, v: V): void {
     const missingU: { ...T, ...V } = o; // error, missing U
     const missingV: { ...T, ...U } = o; // error, missing V
     const atEnd: { ...T, ...U, second: string } = { ...t, ...u, second: 'foo' }; // ok
-    const atBeginning: { first: string, ...T, ...U, } = { first: 'foo', ...t, ...u }; // ok
+    const atBeginning: { first: string, ...T, ...U, } = { first: 'foo', ...t, ...u }; // error, not assignable
 
     const emptyTarget: { } = { ...t, ...u } // ok
     const emptySource: { ...T, ...U } = { }; // error, {} is not assignable to U (or T)
 
+    // error, { sn?: boolean } ...T ... { sn?: number | string } is not assignable to
+    //        T ... { sn?: number | string | boolean }
     let optionalNumber: { sn?: number };
     let optionalString: { sn?: string };
     let optionalBoolean: { sn?: boolean };
     const unionCutoff: { ...T, sn?: number | string | boolean } =
-        { ...optionalBoolean, ...t, ...optionalString, ...optionalNumber } // ok
+        { ...optionalBoolean, ...t, ...optionalString, ...optionalNumber }
     unionCutoff.sn; // ok
     const optionalCutoff = { ...t, ...optionalNumber }; // ok
     optionalCutoff.sn; // ok
 
     const interspersed: { first: string, ...T, second: string, ...U, third: string } =
-        { first: '1', ...t, second: '2', ...u, third: '3' }; // ok
+        { first: '1', ...t, second: '2', ...u, third: '3' }; // error, not assignable
     const interspersedMissingU: { first: string, second: string, ...T, third: string } =
         { first: '1', ...t, second: '2', ...u, third: '3' }; // error, 'U' is missing
     const interspersedOrder1: { first: string, ...T, second: string, ...U, third: string, secondsecond: string } =
-        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // ok
+        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // error, not assignable
     const interspersedOrder2: { first: string, second: string, secondsecond: string, third: string, ...T, ...U } =
-        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // ok
+        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // error, not assignable
 
 
     const mismatchFirst: { first: string, ...T, second: string, ...U, third: string } =
-        { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, 'first' not found
+        { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, not assignable
     const mismatchSecond: { first: string, ...T, second: string, ...U, third: string } =
-        { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, 'second' not found
+        { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, not assignable
     const mismatchLast: { first: string, ...T, second: string, ...U, third: string } =
-        { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, 'third' not found
+        { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, not assignable
 }
 
 
@@ -71,21 +73,23 @@ function f(t, u, v) {
     var missingU = o; // error, missing U
     var missingV = o; // error, missing V
     var atEnd = __assign({}, t, u, { second: 'foo' }); // ok
-    var atBeginning = __assign({ first: 'foo' }, t, u); // ok
+    var atBeginning = __assign({ first: 'foo' }, t, u); // error, not assignable
     var emptyTarget = __assign({}, t, u); // ok
     var emptySource = {}; // error, {} is not assignable to U (or T)
+    // error, { sn?: boolean } ...T ... { sn?: number | string } is not assignable to
+    //        T ... { sn?: number | string | boolean }
     var optionalNumber;
     var optionalString;
     var optionalBoolean;
-    var unionCutoff = __assign({}, optionalBoolean, t, optionalString, optionalNumber); // ok
+    var unionCutoff = __assign({}, optionalBoolean, t, optionalString, optionalNumber);
     unionCutoff.sn; // ok
     var optionalCutoff = __assign({}, t, optionalNumber); // ok
     optionalCutoff.sn; // ok
-    var interspersed = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3' }); // ok
+    var interspersed = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3' }); // error, not assignable
     var interspersedMissingU = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3' }); // error, 'U' is missing
-    var interspersedOrder1 = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3', secondsecond: 'false' }); // ok
-    var interspersedOrder2 = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3', secondsecond: 'false' }); // ok
-    var mismatchFirst = __assign({ firrrrrrst: '1' }, t, { second: '2' }, u, { third: '3' }); // error, 'first' not found
-    var mismatchSecond = __assign({ first: '1' }, t, { ssssssssecond: '2' }, u, { third: '3' }); // error, 'second' not found
-    var mismatchLast = __assign({ first: '1' }, t, { second: '2' }, u, { thirrrrrrrd: '3' }); // error, 'third' not found
+    var interspersedOrder1 = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3', secondsecond: 'false' }); // error, not assignable
+    var interspersedOrder2 = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3', secondsecond: 'false' }); // error, not assignable
+    var mismatchFirst = __assign({ firrrrrrst: '1' }, t, { second: '2' }, u, { third: '3' }); // error, not assignable
+    var mismatchSecond = __assign({ first: '1' }, t, { ssssssssecond: '2' }, u, { third: '3' }); // error, not assignable
+    var mismatchLast = __assign({ first: '1' }, t, { second: '2' }, u, { thirrrrrrrd: '3' }); // error, not assignable
 }
diff --git a/tests/baselines/reference/objectSpreadIntersection.js b/tests/baselines/reference/objectSpreadIntersection.js
index cb93c54796334..0a7f1ddfcee43 100644
--- a/tests/baselines/reference/objectSpreadIntersection.js
+++ b/tests/baselines/reference/objectSpreadIntersection.js
@@ -2,9 +2,9 @@
 function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tu: T | U;
     let uv: U & V;
-    let result = { id: 'bar', ...tu, ...uv };
-    let expected: ({ id: string, ...T, ...U } & { id: string, ...T, ...V }) | ({ id: string, ...U } & { id: string, ...U, ...V });
-    let assignable: { id: string, ...(T | U), ...(U & V) } = result;
+    let result = { ...tu, ...uv, id: 'foo' };
+    let expected: ({ ...T, ...U, id: string } & { ...T, ...V, id: string }) | ({ ...U, id: string } & { ...U, ...V, id: string });
+    let assignable: { ...(T | U), ...(U & V), id: string } = result;
 }
 // concrete types work
 interface A1 { a: number }
@@ -16,23 +16,23 @@ let assignable: { ...(A1 & A2) } = result;
 
 function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tuv: T & U & V;
-    let result = { id: 'foo', ...tuv };
-    let expected: { id: string, ...T } & { id: string, ...U } & { id: string, ...V } = result;
-    let assignable: { id: string, ...(T & U & V) } = result;
+    let result = { ...tuv, id: 'bar' };
+    let expected: { ...T, id: string } & { ...U, id: string } & { ...V, id: string } = result;
+    let assignable: { ...(T & U & V), id: string } = result;
 }
 function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tu: T & U;
     let uv: U & V;
-    let result = { id: 'bar', ...tu, ...uv };
-    let expected: { id: string, ...T, ...U } & { id: string, ...T, ...V } & { id: string, ...U } & { id: string, ...U, ...V };
-    let assignable: { id: string, ...(T & U), ...(U & V) } = result;
+    let result = { ...tu, ...uv, id: 'baz' };
+    let expected: { ...T, ...U, id: string } & { ...T, ...V, id: string } & { ...U, id: string } & { ...U, ...V, id: string };
+    let assignable: { ...(T & U), ...(U & V), id: string } = result;
 }
 function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
     let tu: T & U;
     let uv: U | V;
-    let result = { id: 'bar', ...tu, ...uv };
-    let expected: ({ id: string, ...T, ...U } & { id: string, ...U }) | ({ id: string, ...T, ...V } & { id: string, ...U, ...V });
-    let assignable: { id: string, ...(T & U), ...(U | V) } = result;
+    let result = { ...tu, ...uv, id: 'qux' };
+    let expected: ({ ...T, ...U, id: string } & { ...U, id: string }) | ({ ...T, ...V, id: string } & { ...U, ...V, id: string });
+    let assignable: { ...(T & U), ...(U | V), id: string } = result;
 }
 
 
@@ -49,7 +49,7 @@ var __assign = (this && this.__assign) || Object.assign || function(t) {
 function iteratedUnionIntersection(t, u, v) {
     var tu;
     var uv;
-    var result = __assign({ id: 'bar' }, tu, uv);
+    var result = __assign({}, tu, uv, { id: 'foo' });
     var expected;
     var assignable = result;
 }
@@ -59,21 +59,21 @@ var sn = result.a;
 var assignable = result;
 function tripleIntersection(t, u, v) {
     var tuv;
-    var result = __assign({ id: 'foo' }, tuv);
+    var result = __assign({}, tuv, { id: 'bar' });
     var expected = result;
     var assignable = result;
 }
 function iteratedDoubleIntersection(t, u, v) {
     var tu;
     var uv;
-    var result = __assign({ id: 'bar' }, tu, uv);
+    var result = __assign({}, tu, uv, { id: 'baz' });
     var expected;
     var assignable = result;
 }
 function iteratedIntersectionUnion(t, u, v) {
     var tu;
     var uv;
-    var result = __assign({ id: 'bar' }, tu, uv);
+    var result = __assign({}, tu, uv, { id: 'qux' });
     var expected;
     var assignable = result;
 }
diff --git a/tests/baselines/reference/objectSpreadIntersection.symbols b/tests/baselines/reference/objectSpreadIntersection.symbols
index f45b04a20a51c..c59c37670b25d 100644
--- a/tests/baselines/reference/objectSpreadIntersection.symbols
+++ b/tests/baselines/reference/objectSpreadIntersection.symbols
@@ -21,31 +21,31 @@ function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
 
-    let result = { id: 'bar', ...tu, ...uv };
+    let result = { ...tu, ...uv, id: 'foo' };
 >result : Symbol(result, Decl(objectSpreadIntersection.ts, 3, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 3, 18))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 3, 32))
 
-    let expected: ({ id: string, ...T, ...U } & { id: string, ...T, ...V }) | ({ id: string, ...U } & { id: string, ...U, ...V });
+    let expected: ({ ...T, ...U, id: string } & { ...T, ...V, id: string }) | ({ ...U, id: string } & { ...U, ...V, id: string });
 >expected : Symbol(expected, Decl(objectSpreadIntersection.ts, 4, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 20))
 >T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 49))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 32))
 >T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 80))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 61))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 103))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 86))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 115))
 
-    let assignable: { id: string, ...(T | U), ...(U & V) } = result;
+    let assignable: { ...(T | U), ...(U & V), id: string } = result;
 >assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 5, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 5, 21))
 >T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 5, 45))
 >result : Symbol(result, Decl(objectSpreadIntersection.ts, 3, 7))
 }
 // concrete types work
@@ -95,26 +95,26 @@ function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
 
-    let result = { id: 'foo', ...tuv };
+    let result = { ...tuv, id: 'bar' };
 >result : Symbol(result, Decl(objectSpreadIntersection.ts, 17, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 17, 18))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 17, 26))
 
-    let expected: { id: string, ...T } & { id: string, ...U } & { id: string, ...V } = result;
+    let expected: { ...T, id: string } & { ...U, id: string } & { ...V, id: string } = result;
 >expected : Symbol(expected, Decl(objectSpreadIntersection.ts, 18, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 18, 19))
 >T : Symbol(T, Decl(objectSpreadIntersection.ts, 15, 28))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 18, 42))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 18, 25))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 18, 65))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 18, 48))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 18, 71))
 >result : Symbol(result, Decl(objectSpreadIntersection.ts, 17, 7))
 
-    let assignable: { id: string, ...(T & U & V) } = result;
+    let assignable: { ...(T & U & V), id: string } = result;
 >assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 19, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 19, 21))
 >T : Symbol(T, Decl(objectSpreadIntersection.ts, 15, 28))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 19, 37))
 >result : Symbol(result, Decl(objectSpreadIntersection.ts, 17, 7))
 }
 function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
@@ -139,31 +139,31 @@ function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
 
-    let result = { id: 'bar', ...tu, ...uv };
+    let result = { ...tu, ...uv, id: 'baz' };
 >result : Symbol(result, Decl(objectSpreadIntersection.ts, 24, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 24, 18))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 24, 32))
 
-    let expected: { id: string, ...T, ...U } & { id: string, ...T, ...V } & { id: string, ...U } & { id: string, ...U, ...V };
+    let expected: { ...T, ...U, id: string } & { ...T, ...V, id: string } & { ...U, id: string } & { ...U, ...V, id: string };
 >expected : Symbol(expected, Decl(objectSpreadIntersection.ts, 25, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 19))
 >T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 48))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 31))
 >T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 77))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 60))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 100))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 83))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 112))
 
-    let assignable: { id: string, ...(T & U), ...(U & V) } = result;
+    let assignable: { ...(T & U), ...(U & V), id: string } = result;
 >assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 26, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 26, 21))
 >T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 26, 45))
 >result : Symbol(result, Decl(objectSpreadIntersection.ts, 24, 7))
 }
 function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
@@ -188,31 +188,31 @@ function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
 
-    let result = { id: 'bar', ...tu, ...uv };
+    let result = { ...tu, ...uv, id: 'qux' };
 >result : Symbol(result, Decl(objectSpreadIntersection.ts, 31, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 31, 18))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 31, 32))
 
-    let expected: ({ id: string, ...T, ...U } & { id: string, ...U }) | ({ id: string, ...T, ...V } & { id: string, ...U, ...V });
+    let expected: ({ ...T, ...U, id: string } & { ...U, id: string }) | ({ ...T, ...V, id: string } & { ...U, ...V, id: string });
 >expected : Symbol(expected, Decl(objectSpreadIntersection.ts, 32, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 20))
 >T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 49))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 32))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 74))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 55))
 >T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 103))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 86))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 115))
 
-    let assignable: { id: string, ...(T & U), ...(U | V) } = result;
+    let assignable: { ...(T & U), ...(U | V), id: string } = result;
 >assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 33, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 33, 21))
 >T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 33, 45))
 >result : Symbol(result, Decl(objectSpreadIntersection.ts, 31, 7))
 }
 
diff --git a/tests/baselines/reference/objectSpreadIntersection.types b/tests/baselines/reference/objectSpreadIntersection.types
index 7700d8aa384d3..308200179166c 100644
--- a/tests/baselines/reference/objectSpreadIntersection.types
+++ b/tests/baselines/reference/objectSpreadIntersection.types
@@ -21,17 +21,16 @@ function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
 >U : U
 >V : V
 
-    let result = { id: 'bar', ...tu, ...uv };
->result : ({ id: string; ...T; ...U } | { id: string; ...U }) & ({ id: string; ...T; ...V } | { id: string; ...U; ...V })
->{ id: 'bar', ...tu, ...uv } : ({ id: string; ...T; ...U } | { id: string; ...U }) & ({ id: string; ...T; ...V } | { id: string; ...U; ...V })
->id : string
->'bar' : "bar"
+    let result = { ...tu, ...uv, id: 'foo' };
+>result : ({ ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...U; ...T; ...U; id: string; }) & ({ ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; } | { ...T; ...U; ...T; ...V; id: string; } | { ...U; ...T; ...U; ...V; id: string; })
+>{ ...tu, ...uv, id: 'foo' } : ({ ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...U; ...T; ...U; id: string; }) & ({ ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; } | { ...T; ...U; ...T; ...V; id: string; } | { ...U; ...T; ...U; ...V; id: string; })
 >tu : any
 >uv : any
-
-    let expected: ({ id: string, ...T, ...U } & { id: string, ...T, ...V }) | ({ id: string, ...U } & { id: string, ...U, ...V });
->expected : ({ id: string; ...T; ...U } & { id: string; ...T; ...V }) | ({ id: string; ...U } & { id: string; ...U; ...V })
 >id : string
+>'foo' : "foo"
+
+    let expected: ({ ...T, ...U, id: string } & { ...T, ...V, id: string }) | ({ ...U, id: string } & { ...U, ...V, id: string });
+>expected : ({ ...T; ...U; id: string; } & { ...T; ...V; id: string; }) | ({ ...U; id: string; } & { ...U; ...V; id: string; })
 >T : T
 >U : U
 >id : string
@@ -42,15 +41,16 @@ function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
 >id : string
 >U : U
 >V : V
-
-    let assignable: { id: string, ...(T | U), ...(U & V) } = result;
->assignable : ({ id: string; ...T; ...U } | { id: string; ...U }) & ({ id: string; ...T; ...V } | { id: string; ...U; ...V })
 >id : string
+
+    let assignable: { ...(T | U), ...(U & V), id: string } = result;
+>assignable : ({ ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...U; ...T; ...U; id: string; }) & ({ ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; } | { ...T; ...U; ...T; ...V; id: string; } | { ...U; ...T; ...U; ...V; id: string; })
 >T : T
 >U : U
 >U : U
 >V : V
->result : ({ id: string; ...T; ...U } | { id: string; ...U }) & ({ id: string; ...T; ...V } | { id: string; ...U; ...V })
+>id : string
+>result : ({ ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...U; ...T; ...U; id: string; }) & ({ ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; } | { ...T; ...U; ...T; ...V; id: string; } | { ...U; ...T; ...U; ...V; id: string; })
 }
 // concrete types work
 interface A1 { a: number }
@@ -101,30 +101,30 @@ function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
 >U : U
 >V : V
 
-    let result = { id: 'foo', ...tuv };
->result : { id: string; ...T } & { id: string; ...U } & { id: string; ...V }
->{ id: 'foo', ...tuv } : { id: string; ...T } & { id: string; ...U } & { id: string; ...V }
->id : string
->'foo' : "foo"
+    let result = { ...tuv, id: 'bar' };
+>result : { ...T; id: string; } & { ...U; id: string; } & { ...V; id: string; }
+>{ ...tuv, id: 'bar' } : { ...T; id: string; } & { ...U; id: string; } & { ...V; id: string; }
 >tuv : any
-
-    let expected: { id: string, ...T } & { id: string, ...U } & { id: string, ...V } = result;
->expected : { id: string; ...T } & { id: string; ...U } & { id: string; ...V }
 >id : string
+>'bar' : "bar"
+
+    let expected: { ...T, id: string } & { ...U, id: string } & { ...V, id: string } = result;
+>expected : { ...T; id: string; } & { ...U; id: string; } & { ...V; id: string; }
 >T : T
 >id : string
 >U : U
 >id : string
 >V : V
->result : { id: string; ...T } & { id: string; ...U } & { id: string; ...V }
-
-    let assignable: { id: string, ...(T & U & V) } = result;
->assignable : { id: string; ...T } & { id: string; ...U } & { id: string; ...V }
 >id : string
+>result : { ...T; id: string; } & { ...U; id: string; } & { ...V; id: string; }
+
+    let assignable: { ...(T & U & V), id: string } = result;
+>assignable : { ...T; id: string; } & { ...U; id: string; } & { ...V; id: string; }
 >T : T
 >U : U
 >V : V
->result : { id: string; ...T } & { id: string; ...U } & { id: string; ...V }
+>id : string
+>result : { ...T; id: string; } & { ...U; id: string; } & { ...V; id: string; }
 }
 function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
 >iteratedDoubleIntersection : <T, U, V>(t: T, u: U, v: V) => void
@@ -148,17 +148,16 @@ function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
 >U : U
 >V : V
 
-    let result = { id: 'bar', ...tu, ...uv };
->result : { id: string; ...T; ...U } & { id: string; ...U } & { id: string; ...T; ...V } & { id: string; ...U; ...V }
->{ id: 'bar', ...tu, ...uv } : { id: string; ...T; ...U } & { id: string; ...U } & { id: string; ...T; ...V } & { id: string; ...U; ...V }
->id : string
->'bar' : "bar"
+    let result = { ...tu, ...uv, id: 'baz' };
+>result : { ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...U; id: string; } & { ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; }
+>{ ...tu, ...uv, id: 'baz' } : { ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...U; id: string; } & { ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; }
 >tu : any
 >uv : any
-
-    let expected: { id: string, ...T, ...U } & { id: string, ...T, ...V } & { id: string, ...U } & { id: string, ...U, ...V };
->expected : { id: string; ...T; ...U } & { id: string; ...T; ...V } & { id: string; ...U } & { id: string; ...U; ...V }
 >id : string
+>'baz' : "baz"
+
+    let expected: { ...T, ...U, id: string } & { ...T, ...V, id: string } & { ...U, id: string } & { ...U, ...V, id: string };
+>expected : { ...T; ...U; id: string; } & { ...T; ...V; id: string; } & { ...U; id: string; } & { ...U; ...V; id: string; }
 >T : T
 >U : U
 >id : string
@@ -169,15 +168,16 @@ function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
 >id : string
 >U : U
 >V : V
-
-    let assignable: { id: string, ...(T & U), ...(U & V) } = result;
->assignable : { id: string; ...T; ...U } & { id: string; ...U } & { id: string; ...T; ...V } & { id: string; ...U; ...V }
 >id : string
+
+    let assignable: { ...(T & U), ...(U & V), id: string } = result;
+>assignable : { ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...U; id: string; } & { ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; }
 >T : T
 >U : U
 >U : U
 >V : V
->result : { id: string; ...T; ...U } & { id: string; ...U } & { id: string; ...T; ...V } & { id: string; ...U; ...V }
+>id : string
+>result : { ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...U; id: string; } & { ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; }
 }
 function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
 >iteratedIntersectionUnion : <T, U, V>(t: T, u: U, v: V) => void
@@ -201,17 +201,16 @@ function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
 >U : U
 >V : V
 
-    let result = { id: 'bar', ...tu, ...uv };
->result : ({ id: string; ...T; ...U } & { id: string; ...U }) | ({ id: string; ...T; ...V } & { id: string; ...U; ...V })
->{ id: 'bar', ...tu, ...uv } : ({ id: string; ...T; ...U } & { id: string; ...U }) | ({ id: string; ...T; ...V } & { id: string; ...U; ...V })
->id : string
->'bar' : "bar"
+    let result = { ...tu, ...uv, id: 'qux' };
+>result : ({ ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...T; ...U; ...T; ...U; id: string; } & { ...U; id: string; }) | ({ ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; })
+>{ ...tu, ...uv, id: 'qux' } : ({ ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...T; ...U; ...T; ...U; id: string; } & { ...U; id: string; }) | ({ ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; })
 >tu : any
 >uv : any
-
-    let expected: ({ id: string, ...T, ...U } & { id: string, ...U }) | ({ id: string, ...T, ...V } & { id: string, ...U, ...V });
->expected : ({ id: string; ...T; ...U } & { id: string; ...U }) | ({ id: string; ...T; ...V } & { id: string; ...U; ...V })
 >id : string
+>'qux' : "qux"
+
+    let expected: ({ ...T, ...U, id: string } & { ...U, id: string }) | ({ ...T, ...V, id: string } & { ...U, ...V, id: string });
+>expected : ({ ...T; ...U; id: string; } & { ...U; id: string; }) | ({ ...T; ...V; id: string; } & { ...U; ...V; id: string; })
 >T : T
 >U : U
 >id : string
@@ -222,15 +221,16 @@ function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
 >id : string
 >U : U
 >V : V
-
-    let assignable: { id: string, ...(T & U), ...(U | V) } = result;
->assignable : ({ id: string; ...T; ...U } & { id: string; ...U }) | ({ id: string; ...T; ...V } & { id: string; ...U; ...V })
 >id : string
+
+    let assignable: { ...(T & U), ...(U | V), id: string } = result;
+>assignable : ({ ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...T; ...U; ...T; ...U; id: string; } & { ...U; id: string; }) | ({ ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; })
 >T : T
 >U : U
 >U : U
 >V : V
->result : ({ id: string; ...T; ...U } & { id: string; ...U }) | ({ id: string; ...T; ...V } & { id: string; ...U; ...V })
+>id : string
+>result : ({ ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...T; ...U; ...T; ...U; id: string; } & { ...U; id: string; }) | ({ ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; })
 }
 
 
diff --git a/tests/baselines/reference/objectSpreadUnion.js b/tests/baselines/reference/objectSpreadUnion.js
index 500b8a5ddc7ca..b3a114c772218 100644
--- a/tests/baselines/reference/objectSpreadUnion.js
+++ b/tests/baselines/reference/objectSpreadUnion.js
@@ -9,16 +9,16 @@ let assignable: { ...(A1 | A2) } = result;
 
 function tripleUnion<T, U, V>(t: T, u: U, v: V): void {
     let tuv: T | U | V;
-    let result = { id: 'foo', ...tuv };
-    let expected: { id: string, ...T } | { id: string, ...U } | { id: string, ...V } = result;
-    let assignable: { id: string, ...(T | U | V) } = result;
+    let result = { ...tuv, id: 'foo' };
+    let expected: { ...T, id: string } | { ...U, id: string } | { ...V, id: string } = result;
+    let assignable: { ...(T | U | V), id: string } = result;
 }
 function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
     let tu: T | U;
     let uv: U | V;
-    let result = { id: 'bar', ...tu, ...uv };
-    let expected: { id: string, ...T, ...U } | { id: string, ...T, ...V } | { id: string, ...U } | { id: string, ...U, ...V };
-    let assignable: { id: string, ...(T | U), ...(U | V) } = result;
+    let result = { ...tu, ...uv, id: 'bar' };
+    let expected: { ...T, ...U, id: string } | { ...T, ...V, id: string } | { ...U, id: string } | { ...U, ...V, id: string };
+    let assignable: { ...(T | U), ...(U | V), id: string } = result;
 }
 
 
@@ -39,14 +39,14 @@ var sn = result.a;
 var assignable = result;
 function tripleUnion(t, u, v) {
     var tuv;
-    var result = __assign({ id: 'foo' }, tuv);
+    var result = __assign({}, tuv, { id: 'foo' });
     var expected = result;
     var assignable = result;
 }
 function iteratedDoubleUnion(t, u, v) {
     var tu;
     var uv;
-    var result = __assign({ id: 'bar' }, tu, uv);
+    var result = __assign({}, tu, uv, { id: 'bar' });
     var expected;
     var assignable = result;
 }
diff --git a/tests/baselines/reference/objectSpreadUnion.symbols b/tests/baselines/reference/objectSpreadUnion.symbols
index eea9e65185d0a..d630fde518b52 100644
--- a/tests/baselines/reference/objectSpreadUnion.symbols
+++ b/tests/baselines/reference/objectSpreadUnion.symbols
@@ -46,26 +46,26 @@ function tripleUnion<T, U, V>(t: T, u: U, v: V): void {
 >U : Symbol(U, Decl(objectSpreadUnion.ts, 8, 23))
 >V : Symbol(V, Decl(objectSpreadUnion.ts, 8, 26))
 
-    let result = { id: 'foo', ...tuv };
+    let result = { ...tuv, id: 'foo' };
 >result : Symbol(result, Decl(objectSpreadUnion.ts, 10, 7))
->id : Symbol(id, Decl(objectSpreadUnion.ts, 10, 18))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 10, 26))
 
-    let expected: { id: string, ...T } | { id: string, ...U } | { id: string, ...V } = result;
+    let expected: { ...T, id: string } | { ...U, id: string } | { ...V, id: string } = result;
 >expected : Symbol(expected, Decl(objectSpreadUnion.ts, 11, 7))
->id : Symbol(id, Decl(objectSpreadUnion.ts, 11, 19))
 >T : Symbol(T, Decl(objectSpreadUnion.ts, 8, 21))
->id : Symbol(id, Decl(objectSpreadUnion.ts, 11, 42))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 11, 25))
 >U : Symbol(U, Decl(objectSpreadUnion.ts, 8, 23))
->id : Symbol(id, Decl(objectSpreadUnion.ts, 11, 65))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 11, 48))
 >V : Symbol(V, Decl(objectSpreadUnion.ts, 8, 26))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 11, 71))
 >result : Symbol(result, Decl(objectSpreadUnion.ts, 10, 7))
 
-    let assignable: { id: string, ...(T | U | V) } = result;
+    let assignable: { ...(T | U | V), id: string } = result;
 >assignable : Symbol(assignable, Decl(objectSpreadUnion.ts, 12, 7))
->id : Symbol(id, Decl(objectSpreadUnion.ts, 12, 21))
 >T : Symbol(T, Decl(objectSpreadUnion.ts, 8, 21))
 >U : Symbol(U, Decl(objectSpreadUnion.ts, 8, 23))
 >V : Symbol(V, Decl(objectSpreadUnion.ts, 8, 26))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 12, 37))
 >result : Symbol(result, Decl(objectSpreadUnion.ts, 10, 7))
 }
 function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
@@ -90,31 +90,31 @@ function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
 >U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
 >V : Symbol(V, Decl(objectSpreadUnion.ts, 14, 34))
 
-    let result = { id: 'bar', ...tu, ...uv };
+    let result = { ...tu, ...uv, id: 'bar' };
 >result : Symbol(result, Decl(objectSpreadUnion.ts, 17, 7))
->id : Symbol(id, Decl(objectSpreadUnion.ts, 17, 18))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 17, 32))
 
-    let expected: { id: string, ...T, ...U } | { id: string, ...T, ...V } | { id: string, ...U } | { id: string, ...U, ...V };
+    let expected: { ...T, ...U, id: string } | { ...T, ...V, id: string } | { ...U, id: string } | { ...U, ...V, id: string };
 >expected : Symbol(expected, Decl(objectSpreadUnion.ts, 18, 7))
->id : Symbol(id, Decl(objectSpreadUnion.ts, 18, 19))
 >T : Symbol(T, Decl(objectSpreadUnion.ts, 14, 29))
 >U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
->id : Symbol(id, Decl(objectSpreadUnion.ts, 18, 48))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 18, 31))
 >T : Symbol(T, Decl(objectSpreadUnion.ts, 14, 29))
 >V : Symbol(V, Decl(objectSpreadUnion.ts, 14, 34))
->id : Symbol(id, Decl(objectSpreadUnion.ts, 18, 77))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 18, 60))
 >U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
->id : Symbol(id, Decl(objectSpreadUnion.ts, 18, 100))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 18, 83))
 >U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
 >V : Symbol(V, Decl(objectSpreadUnion.ts, 14, 34))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 18, 112))
 
-    let assignable: { id: string, ...(T | U), ...(U | V) } = result;
+    let assignable: { ...(T | U), ...(U | V), id: string } = result;
 >assignable : Symbol(assignable, Decl(objectSpreadUnion.ts, 19, 7))
->id : Symbol(id, Decl(objectSpreadUnion.ts, 19, 21))
 >T : Symbol(T, Decl(objectSpreadUnion.ts, 14, 29))
 >U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
 >U : Symbol(U, Decl(objectSpreadUnion.ts, 14, 31))
 >V : Symbol(V, Decl(objectSpreadUnion.ts, 14, 34))
+>id : Symbol(id, Decl(objectSpreadUnion.ts, 19, 45))
 >result : Symbol(result, Decl(objectSpreadUnion.ts, 17, 7))
 }
 
diff --git a/tests/baselines/reference/objectSpreadUnion.types b/tests/baselines/reference/objectSpreadUnion.types
index 7cbffcf0a584c..5d8cdbae24a70 100644
--- a/tests/baselines/reference/objectSpreadUnion.types
+++ b/tests/baselines/reference/objectSpreadUnion.types
@@ -48,30 +48,30 @@ function tripleUnion<T, U, V>(t: T, u: U, v: V): void {
 >U : U
 >V : V
 
-    let result = { id: 'foo', ...tuv };
->result : { id: string; ...T } | { id: string; ...U } | { id: string; ...V }
->{ id: 'foo', ...tuv } : { id: string; ...T } | { id: string; ...U } | { id: string; ...V }
+    let result = { ...tuv, id: 'foo' };
+>result : { ...T; id: string; } | { ...U; id: string; } | { ...V; id: string; }
+>{ ...tuv, id: 'foo' } : { ...T; id: string; } | { ...U; id: string; } | { ...V; id: string; }
+>tuv : any
 >id : string
 >'foo' : "foo"
->tuv : any
 
-    let expected: { id: string, ...T } | { id: string, ...U } | { id: string, ...V } = result;
->expected : { id: string; ...T } | { id: string; ...U } | { id: string; ...V }
->id : string
+    let expected: { ...T, id: string } | { ...U, id: string } | { ...V, id: string } = result;
+>expected : { ...T; id: string; } | { ...U; id: string; } | { ...V; id: string; }
 >T : T
 >id : string
 >U : U
 >id : string
 >V : V
->result : { id: string; ...T } | { id: string; ...U } | { id: string; ...V }
-
-    let assignable: { id: string, ...(T | U | V) } = result;
->assignable : { id: string; ...T } | { id: string; ...U } | { id: string; ...V }
 >id : string
+>result : { ...T; id: string; } | { ...U; id: string; } | { ...V; id: string; }
+
+    let assignable: { ...(T | U | V), id: string } = result;
+>assignable : { ...T; id: string; } | { ...U; id: string; } | { ...V; id: string; }
 >T : T
 >U : U
 >V : V
->result : { id: string; ...T } | { id: string; ...U } | { id: string; ...V }
+>id : string
+>result : { ...T; id: string; } | { ...U; id: string; } | { ...V; id: string; }
 }
 function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
 >iteratedDoubleUnion : <T, U, V>(t: T, u: U, v: V) => void
@@ -95,17 +95,16 @@ function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
 >U : U
 >V : V
 
-    let result = { id: 'bar', ...tu, ...uv };
->result : { id: string; ...T; ...U } | { id: string; ...U } | { id: string; ...T; ...V } | { id: string; ...U; ...V }
->{ id: 'bar', ...tu, ...uv } : { id: string; ...T; ...U } | { id: string; ...U } | { id: string; ...T; ...V } | { id: string; ...U; ...V }
->id : string
->'bar' : "bar"
+    let result = { ...tu, ...uv, id: 'bar' };
+>result : { ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; }
+>{ ...tu, ...uv, id: 'bar' } : { ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; }
 >tu : any
 >uv : any
-
-    let expected: { id: string, ...T, ...U } | { id: string, ...T, ...V } | { id: string, ...U } | { id: string, ...U, ...V };
->expected : { id: string; ...T; ...U } | { id: string; ...T; ...V } | { id: string; ...U } | { id: string; ...U; ...V }
 >id : string
+>'bar' : "bar"
+
+    let expected: { ...T, ...U, id: string } | { ...T, ...V, id: string } | { ...U, id: string } | { ...U, ...V, id: string };
+>expected : { ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; id: string; } | { ...U; ...V; id: string; }
 >T : T
 >U : U
 >id : string
@@ -116,15 +115,16 @@ function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
 >id : string
 >U : U
 >V : V
-
-    let assignable: { id: string, ...(T | U), ...(U | V) } = result;
->assignable : { id: string; ...T; ...U } | { id: string; ...U } | { id: string; ...T; ...V } | { id: string; ...U; ...V }
 >id : string
+
+    let assignable: { ...(T | U), ...(U | V), id: string } = result;
+>assignable : { ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; }
 >T : T
 >U : U
 >U : U
 >V : V
->result : { id: string; ...T; ...U } | { id: string; ...U } | { id: string; ...T; ...V } | { id: string; ...U; ...V }
+>id : string
+>result : { ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; }
 }
 
 
diff --git a/tests/cases/conformance/types/spread/objectSpread.ts b/tests/cases/conformance/types/spread/objectSpread.ts
index fc076e79543de..e35a84956c00a 100644
--- a/tests/cases/conformance/types/spread/objectSpread.ts
+++ b/tests/cases/conformance/types/spread/objectSpread.ts
@@ -83,8 +83,8 @@ let a = 12;
 let shortCutted: { a: number, b: string } = { ...o, a }
 
 // generics
-function f<T, U>(t: T, u: U): { id: string, ...T, ...U } {
-    return { id: 'id', ...t, ...u };
+function f<T, U>(t: T, u: U): { ...T, ...U, id: string } {
+    return { ...t, ...u, id: 'id' };
 }
 let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
     f({ a: 1, b: 'yes' }, { c: 'no', d: false })
@@ -92,7 +92,7 @@ let overlap: { id: string, a: number, b: string } =
     f({ a: 1 }, { a: 2, b: 'extra' })
 let overlapConflict: { id:string, a: string } =
     f({ a: 1 }, { a: 'mismatch' })
-let overwriteId: { id: boolean, a: number, c: number, d: string } =
+let overwriteId: { id: string, a: number, c: number, d: string } =
     f({ a: 1, id: true }, { c: 1, d: 'no' })
 
 class D { m() { }; q = 2; }
diff --git a/tests/cases/conformance/types/spread/objectSpreadGeneric.ts b/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
index e3bd1ab7bb32a..63e9f00aaae62 100644
--- a/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
@@ -13,34 +13,36 @@ function f<T, U, V>(t: T, u: U, v: V): void {
     const missingU: { ...T, ...V } = o; // error, missing U
     const missingV: { ...T, ...U } = o; // error, missing V
     const atEnd: { ...T, ...U, second: string } = { ...t, ...u, second: 'foo' }; // ok
-    const atBeginning: { first: string, ...T, ...U, } = { first: 'foo', ...t, ...u }; // ok
+    const atBeginning: { first: string, ...T, ...U, } = { first: 'foo', ...t, ...u }; // error, not assignable
 
     const emptyTarget: { } = { ...t, ...u } // ok
     const emptySource: { ...T, ...U } = { }; // error, {} is not assignable to U (or T)
 
+    // error, { sn?: boolean } ...T ... { sn?: number | string } is not assignable to
+    //        T ... { sn?: number | string | boolean }
     let optionalNumber: { sn?: number };
     let optionalString: { sn?: string };
     let optionalBoolean: { sn?: boolean };
     const unionCutoff: { ...T, sn?: number | string | boolean } =
-        { ...optionalBoolean, ...t, ...optionalString, ...optionalNumber } // ok
+        { ...optionalBoolean, ...t, ...optionalString, ...optionalNumber }
     unionCutoff.sn; // ok
     const optionalCutoff = { ...t, ...optionalNumber }; // ok
     optionalCutoff.sn; // ok
 
     const interspersed: { first: string, ...T, second: string, ...U, third: string } =
-        { first: '1', ...t, second: '2', ...u, third: '3' }; // ok
+        { first: '1', ...t, second: '2', ...u, third: '3' }; // error, not assignable
     const interspersedMissingU: { first: string, second: string, ...T, third: string } =
         { first: '1', ...t, second: '2', ...u, third: '3' }; // error, 'U' is missing
     const interspersedOrder1: { first: string, ...T, second: string, ...U, third: string, secondsecond: string } =
-        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // ok
+        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // error, not assignable
     const interspersedOrder2: { first: string, second: string, secondsecond: string, third: string, ...T, ...U } =
-        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // ok
+        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // error, not assignable
 
 
     const mismatchFirst: { first: string, ...T, second: string, ...U, third: string } =
-        { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, 'first' not found
+        { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, not assignable
     const mismatchSecond: { first: string, ...T, second: string, ...U, third: string } =
-        { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, 'second' not found
+        { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, not assignable
     const mismatchLast: { first: string, ...T, second: string, ...U, third: string } =
-        { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, 'third' not found
+        { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, not assignable
 }
diff --git a/tests/cases/conformance/types/spread/objectSpreadIntersection.ts b/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
index 6471e622b68a4..f70995cb4b2fc 100644
--- a/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
@@ -1,9 +1,9 @@
 function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tu: T | U;
     let uv: U & V;
-    let result = { id: 'bar', ...tu, ...uv };
-    let expected: ({ id: string, ...T, ...U } & { id: string, ...T, ...V }) | ({ id: string, ...U } & { id: string, ...U, ...V });
-    let assignable: { id: string, ...(T | U), ...(U & V) } = result;
+    let result = { ...tu, ...uv, id: 'foo' };
+    let expected: ({ ...T, ...U, id: string } & { ...T, ...V, id: string }) | ({ ...U, id: string } & { ...U, ...V, id: string });
+    let assignable: { ...(T | U), ...(U & V), id: string } = result;
 }
 // concrete types work
 interface A1 { a: number }
@@ -15,22 +15,22 @@ let assignable: { ...(A1 & A2) } = result;
 
 function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tuv: T & U & V;
-    let result = { id: 'foo', ...tuv };
-    let expected: { id: string, ...T } & { id: string, ...U } & { id: string, ...V } = result;
-    let assignable: { id: string, ...(T & U & V) } = result;
+    let result = { ...tuv, id: 'bar' };
+    let expected: { ...T, id: string } & { ...U, id: string } & { ...V, id: string } = result;
+    let assignable: { ...(T & U & V), id: string } = result;
 }
 function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tu: T & U;
     let uv: U & V;
-    let result = { id: 'bar', ...tu, ...uv };
-    let expected: { id: string, ...T, ...U } & { id: string, ...T, ...V } & { id: string, ...U } & { id: string, ...U, ...V };
-    let assignable: { id: string, ...(T & U), ...(U & V) } = result;
+    let result = { ...tu, ...uv, id: 'baz' };
+    let expected: { ...T, ...U, id: string } & { ...T, ...V, id: string } & { ...U, id: string } & { ...U, ...V, id: string };
+    let assignable: { ...(T & U), ...(U & V), id: string } = result;
 }
 function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
     let tu: T & U;
     let uv: U | V;
-    let result = { id: 'bar', ...tu, ...uv };
-    let expected: ({ id: string, ...T, ...U } & { id: string, ...U }) | ({ id: string, ...T, ...V } & { id: string, ...U, ...V });
-    let assignable: { id: string, ...(T & U), ...(U | V) } = result;
+    let result = { ...tu, ...uv, id: 'qux' };
+    let expected: ({ ...T, ...U, id: string } & { ...U, id: string }) | ({ ...T, ...V, id: string } & { ...U, ...V, id: string });
+    let assignable: { ...(T & U), ...(U | V), id: string } = result;
 }
 
diff --git a/tests/cases/conformance/types/spread/objectSpreadUnion.ts b/tests/cases/conformance/types/spread/objectSpreadUnion.ts
index 03a4251ca8172..cd490d76bdaf4 100644
--- a/tests/cases/conformance/types/spread/objectSpreadUnion.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadUnion.ts
@@ -8,16 +8,16 @@ let assignable: { ...(A1 | A2) } = result;
 
 function tripleUnion<T, U, V>(t: T, u: U, v: V): void {
     let tuv: T | U | V;
-    let result = { id: 'foo', ...tuv };
-    let expected: { id: string, ...T } | { id: string, ...U } | { id: string, ...V } = result;
-    let assignable: { id: string, ...(T | U | V) } = result;
+    let result = { ...tuv, id: 'foo' };
+    let expected: { ...T, id: string } | { ...U, id: string } | { ...V, id: string } = result;
+    let assignable: { ...(T | U | V), id: string } = result;
 }
 function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
     let tu: T | U;
     let uv: U | V;
-    let result = { id: 'bar', ...tu, ...uv };
-    let expected: { id: string, ...T, ...U } | { id: string, ...T, ...V } | { id: string, ...U } | { id: string, ...U, ...V };
-    let assignable: { id: string, ...(T | U), ...(U | V) } = result;
+    let result = { ...tu, ...uv, id: 'bar' };
+    let expected: { ...T, ...U, id: string } | { ...T, ...V, id: string } | { ...U, id: string } | { ...U, ...V, id: string };
+    let assignable: { ...(T | U), ...(U | V), id: string } = result;
 }
 
 

From 84dc99ba1e187cb9530696349cff7f10fea5c435 Mon Sep 17 00:00:00 2001
From: Ron Buckton <rbuckton@microsoft.com>
Date: Mon, 17 Oct 2016 13:49:15 -0700
Subject: [PATCH 062/224] Moved AMD/CJS/UMD transform to end

---
 src/compiler/binder.ts                        |   21 +-
 src/compiler/core.ts                          |    9 +-
 src/compiler/factory.ts                       |  149 +++
 src/compiler/transformer.ts                   |    9 +-
 src/compiler/transformers/es2015.ts           |  166 +--
 src/compiler/transformers/module/module.ts    | 1090 ++++++++++-------
 src/compiler/transformers/module/system.ts    |    2 +-
 src/compiler/transformers/ts.ts               |  492 +++-----
 src/compiler/types.ts                         |   21 +-
 src/compiler/utilities.ts                     |  134 +-
 .../baselines/reference/ExportAssignment7.js  |    1 -
 .../baselines/reference/ExportAssignment8.js  |    1 -
 .../amdImportNotAsPrimaryExpression.js        |    2 +-
 .../commonJSImportAsPrimaryExpression.js      |    2 +-
 .../commonJSImportNotAsPrimaryExpression.js   |    2 +-
 .../decoratedClassExportsCommonJS1.js         |    4 +-
 .../decoratedClassExportsCommonJS2.js         |    4 +-
 .../reference/decoratedClassExportsSystem1.js |    5 +-
 .../reference/decoratedClassExportsSystem2.js |    5 +-
 .../decoratorMetadataOnInferredType.js        |    2 +-
 .../decoratorMetadataWithConstructorType.js   |    2 +-
 .../reference/decoratorOnClass5.es6.js        |    4 +-
 .../reference/decoratorOnClass6.es6.js        |    4 +-
 .../reference/decoratorOnClass7.es6.js        |    4 +-
 .../reference/defaultExportsCannotMerge02.js  |    2 +-
 .../reference/defaultExportsCannotMerge04.js  |    4 +-
 .../reference/dottedNamesInSystem.js          |    2 +-
 .../reference/es3defaultAliasIsQuoted.js      |    2 +-
 tests/baselines/reference/es5ExportEquals.js  |    1 -
 .../reference/es6modulekindWithES5Target.js   |    3 +-
 .../reference/es6modulekindWithES5Target12.js |    3 +-
 .../reference/exportAssignmentWithExports.js  |    1 -
 tests/baselines/reference/exportEqualsAmd.js  |    2 +-
 .../reference/exportEqualsCommonJs.js         |    2 +-
 tests/baselines/reference/exportEqualsUmd.js  |    2 +-
 tests/baselines/reference/externModule.js     |    3 +-
 .../reference/importImportOnlyModule.js       |    2 +-
 tests/baselines/reference/innerModExport1.js  |    5 +-
 tests/baselines/reference/innerModExport2.js  |    5 +-
 .../invalidModuleWithVarStatements.js         |    4 +-
 .../moduleElementsInWrongContext3.js          |    5 +-
 .../reference/outModuleConcatAmd.js.map       |    2 +-
 .../outModuleConcatAmd.sourcemap.txt          |   12 +-
 .../reference/outModuleTripleSlashRefs.js.map |    2 +-
 .../outModuleTripleSlashRefs.sourcemap.txt    |   14 +-
 .../reference/parserExportAssignment7.js      |    1 -
 .../reference/parserExportAssignment8.js      |    1 -
 .../privacyCannotNameVarTypeDeclFile.js       |    4 +-
 .../amd/ref/m2.js.map                         |    2 +-
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 .../outputdir_module_multifolder/test.js.map  |    2 +-
 .../m2.js.map                                 |    2 +-
 .../ref/m1.js.map                             |    2 +-
 .../outputdir_module_multifolder/test.js.map  |    2 +-
 .../m2.js.map                                 |    2 +-
 .../amd/bin/test.js.map                       |    2 +-
 .../amd/m1.js.map                             |    2 +-
 .../amd/test.js.map                           |    2 +-
 .../node/m1.js.map                            |    2 +-
 .../node/test.js.map                          |    2 +-
 .../amd/outdir/simple/m1.js.map               |    2 +-
 .../amd/outdir/simple/test.js.map             |    2 +-
 .../node/outdir/simple/m1.js.map              |    2 +-
 .../node/outdir/simple/test.js.map            |    2 +-
 .../amd/bin/test.js.map                       |    2 +-
 .../amd/ref/m1.js.map                         |    2 +-
 .../amd/test.js.map                           |    2 +-
 .../node/ref/m1.js.map                        |    2 +-
 .../node/test.js.map                          |    2 +-
 .../amd/outdir/simple/ref/m1.js.map           |    2 +-
 .../amd/outdir/simple/test.js.map             |    2 +-
 .../node/outdir/simple/ref/m1.js.map          |    2 +-
 .../node/outdir/simple/test.js.map            |    2 +-
 .../amd/bin/test.js.map                       |    2 +-
 .../sourceMapValidationDecorators.js.map      |    2 +-
 ...ourceMapValidationDecorators.sourcemap.txt |  112 +-
 tests/baselines/reference/systemModule7.js    |    2 +-
 .../systemModuleDeclarationMerging.js         |    8 +-
 .../systemModuleNonTopLevelModuleMembers.js   |    6 +-
 .../baselines/reference/tsxDefaultImports.js  |    2 +-
 350 files changed, 1647 insertions(+), 1296 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 4711d54e0b267..2b3584be9e0da 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -2566,9 +2566,9 @@ namespace ts {
 
             // A class with a parameter property assignment, property initializer, or decorator is
             // TypeScript syntax.
-            // An exported declaration may be TypeScript syntax.
+            // An exported declaration may be TypeScript syntax, but is handled by the visitor
+            // for a namespace declaration.
             if ((subtreeFlags & TransformFlags.TypeScriptClassSyntaxMask)
-                || (modifierFlags & ModifierFlags.Export)
                 || node.typeParameters) {
                 transformFlags |= TransformFlags.AssertTypeScript;
             }
@@ -2727,11 +2727,6 @@ namespace ts {
         else {
             transformFlags = subtreeFlags | TransformFlags.ContainsHoistedDeclarationOrCompletion;
 
-            // If a FunctionDeclaration is exported, then it is either ES6 or TypeScript syntax.
-            if (modifierFlags & ModifierFlags.Export) {
-                transformFlags |= TransformFlags.AssertTypeScript | TransformFlags.AssertES2015;
-            }
-
             // TypeScript-specific modifiers, type parameters, and type annotations are TypeScript
             // syntax.
             if (modifierFlags & ModifierFlags.TypeScriptModifier
@@ -2873,11 +2868,6 @@ namespace ts {
         else {
             transformFlags = subtreeFlags;
 
-            // If a VariableStatement is exported, then it is either ES6 or TypeScript syntax.
-            if (modifierFlags & ModifierFlags.Export) {
-                transformFlags |= TransformFlags.AssertES2015 | TransformFlags.AssertTypeScript;
-            }
-
             if (declarationListTransformFlags & TransformFlags.ContainsBindingPattern) {
                 transformFlags |= TransformFlags.AssertES2015;
             }
@@ -2994,12 +2984,6 @@ namespace ts {
                 transformFlags |= TransformFlags.AssertJsx;
                 break;
 
-            case SyntaxKind.ExportKeyword:
-                // This node is both ES6 and TypeScript syntax.
-                transformFlags |= TransformFlags.AssertES2015 | TransformFlags.AssertTypeScript;
-                break;
-
-            case SyntaxKind.DefaultKeyword:
             case SyntaxKind.NoSubstitutionTemplateLiteral:
             case SyntaxKind.TemplateHead:
             case SyntaxKind.TemplateMiddle:
@@ -3008,6 +2992,7 @@ namespace ts {
             case SyntaxKind.TaggedTemplateExpression:
             case SyntaxKind.ShorthandPropertyAssignment:
             case SyntaxKind.ForOfStatement:
+            case SyntaxKind.StaticKeyword:
                 // These nodes are ES6 syntax.
                 transformFlags |= TransformFlags.AssertES2015;
                 break;
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index befa30b600618..1dd8ed8ff7f9a 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -485,6 +485,13 @@ namespace ts {
         return result;
     }
 
+    export function append<T>(to: T[] | undefined, value: T | undefined): T[] | undefined {
+        if (value === undefined) return to;
+        if (to === undefined) to = [];
+        to.push(value);
+        return to;
+    }
+
     export function addRange<T>(to: T[], from: T[]): void {
         if (to && from) {
             for (const v of from) {
@@ -830,7 +837,7 @@ namespace ts {
      * Adds the value to an array of values associated with the key, and returns the array.
      * Creates the array if it does not already exist.
      */
-    export function multiMapAdd<V>(map: Map<V[]>, key: string, value: V): V[] {
+    export function multiMapAdd<V>(map: Map<V[]>, key: string | number, value: V): V[] {
         const values = map[key];
         if (values) {
             values.push(value);
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index c42b16c5b8f3f..530d64e8aebe3 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -1461,6 +1461,17 @@ namespace ts {
         return node;
     }
 
+    /**
+     * Creates a synthetic element to act as a placeholder for the end of an emitted declaration in
+     * order to properly emit exports.
+     */
+    export function createEndOfDeclarationMarker(original: Node) {
+        const node = <EndOfDeclarationMarker>createNode(SyntaxKind.EndOfDeclarationMarker);
+        node.emitNode = {};
+        node.original = original;
+        return node;
+    }
+
     /**
      * Creates a synthetic expression to act as a placeholder for a not-emitted expression in
      * order to preserve comments or sourcemap positions.
@@ -1637,6 +1648,18 @@ namespace ts {
         );
     }
 
+    export function createExportDefault(expression: Expression) {
+        return createExportAssignment(/*decorators*/ undefined, /*modifiers*/ undefined, /*isExportEquals*/ false, expression);
+    }
+
+    export function createExternalModuleExport(exportName: Identifier) {
+        return createExportDeclaration(/*decorators*/ undefined, /*modifiers*/ undefined, createNamedExports([createExportSpecifier(exportName)]));
+    }
+
+    export function createLetStatement(name: Identifier, initializer: Expression, location?: TextRange) {
+        return createVariableStatement(/*modifiers*/ undefined, createLetDeclarationList([createVariableDeclaration(name, /*type*/ undefined, initializer)]), location);
+    }
+
     export function createLetDeclarationList(declarations: VariableDeclaration[], location?: TextRange) {
         return createVariableDeclarationList(declarations, location, NodeFlags.Let);
     }
@@ -2165,6 +2188,132 @@ namespace ts {
         );
     }
 
+    /**
+     * Gets the local name of a declaration. This is primarily used for declarations that can be
+     * referred to by name in the declaration's immediate scope (classes, enums, namespaces). A
+     * local name will *never* be prefixed with an module or namespace export modifier like
+     * "exports." when emitted as an expression.
+     *
+     * @param node The declaration.
+     * @param allowComments A value indicating whether comments may be emitted for the name.
+     * @param allowSourceMaps A value indicating whether source maps may be emitted for the name.
+     */
+    export function getLocalName(node: Declaration, allowComments?: boolean, allowSourceMaps?: boolean) {
+        return getName(node, allowComments, allowSourceMaps, EmitFlags.LocalName);
+    }
+
+    /**
+     * Gets whether an identifier should only be referred to by its local name.
+     */
+    export function isLocalName(node: Identifier) {
+        return (getEmitFlags(node) & EmitFlags.ExportBindingName) === EmitFlags.LocalName;
+    }
+
+    /**
+     * Gets the export name of a declaration. This is primarily used for declarations that can be
+     * referred to by name in the declaration's immediate scope (classes, enums, namespaces). An
+     * export name will *always* be prefixed with an module or namespace export modifier like
+     * `"exports."` when emitted as an expression if the name points to an exported symbol.
+     *
+     * @param node The declaration.
+     * @param allowComments A value indicating whether comments may be emitted for the name.
+     * @param allowSourceMaps A value indicating whether source maps may be emitted for the name.
+     */
+    export function getExportName(node: Declaration, allowComments?: boolean, allowSourceMaps?: boolean): Identifier {
+        return getName(node, allowComments, allowSourceMaps, EmitFlags.ExportName);
+    }
+
+    /**
+     * Gets whether an identifier should only be referred to by its export representation if the
+     * name points to an exported symbol.
+     */
+    export function isExportName(node: Identifier) {
+        return (getEmitFlags(node) & EmitFlags.ExportBindingName) === EmitFlags.ExportName;
+    }
+
+    /**
+     * Gets the export binding name of a declaration for use in the left-hand side of assignment
+     * expressions. This is primarily used for declarations that can be referred to by name in the
+     * declaration's immediate scope (classes, enums, namespaces). If the declaration is exported
+     * and the name is the target of an assignment expression, its export binding name should be
+     * substituted with an expression that assigns *both* the local *and* export names of the
+     * declaration. If an export binding name appears in any other position it should be treated
+     * as a local name.
+     *
+     * @param node The declaration.
+     * @param allowComments A value indicating whether comments may be emitted for the name.
+     * @param allowSourceMaps A value indicating whether source maps may be emitted for the name.
+     */
+    export function getExportBindingName(node: Declaration, allowComments?: boolean, allowSourceMaps?: boolean): Identifier {
+        return getName(node, allowComments, allowSourceMaps, EmitFlags.ExportBindingName);
+    }
+
+    /**
+     * Gets whether an identifier should be treated as both an export name and a local name when
+     * it is the target of an assignment expression.
+     */
+    export function isExportBindingName(node: Identifier) {
+        return (getEmitFlags(node) & EmitFlags.ExportBindingName) === EmitFlags.ExportBindingName;
+    }
+
+    /**
+     * Gets the name of a declaration for use in declarations.
+     *
+     * @param node The declaration.
+     * @param allowComments A value indicating whether comments may be emitted for the name.
+     * @param allowSourceMaps A value indicating whether source maps may be emitted for the name.
+     */
+    export function getDeclarationName(node: Declaration, allowComments?: boolean, allowSourceMaps?: boolean) {
+        return getName(node, allowComments, allowSourceMaps);
+    }
+
+    function getName(node: Declaration, allowComments?: boolean, allowSourceMaps?: boolean, emitFlags?: EmitFlags) {
+        if (node.name && isIdentifier(node.name) && !isGeneratedIdentifier(node.name)) {
+            const name = getMutableClone(node.name);
+            emitFlags |= getEmitFlags(node.name);
+            if (!allowSourceMaps) emitFlags |= EmitFlags.NoSourceMap;
+            if (!allowComments) emitFlags |= EmitFlags.NoComments;
+            if (emitFlags) setEmitFlags(name, emitFlags);
+            return name;
+        }
+        return getGeneratedNameForNode(node);
+    }
+
+    /**
+     * Gets the exported name of a declaration for use in expressions.
+     *
+     * An exported name will *always* be prefixed with an module or namespace export modifier like
+     * "exports." if the name points to an exported symbol.
+     *
+     * @param ns The namespace identifier.
+     * @param node The declaration.
+     * @param allowComments A value indicating whether comments may be emitted for the name.
+     * @param allowSourceMaps A value indicating whether source maps may be emitted for the name.
+     */
+    export function getExternalModuleOrNamespaceExportName(ns: Identifier | undefined, node: Declaration, allowComments?: boolean, allowSourceMaps?: boolean): Identifier | PropertyAccessExpression {
+        if (ns && hasModifier(node, ModifierFlags.Export)) {
+            return getNamespaceMemberName(ns, getName(node), allowComments, allowSourceMaps);
+        }
+        return getExportName(node, allowComments, allowSourceMaps);
+    }
+
+    /**
+     * Gets a namespace-qualified name for use in expressions.
+     *
+     * @param ns The namespace identifier.
+     * @param name The name.
+     * @param allowComments A value indicating whether comments may be emitted for the name.
+     * @param allowSourceMaps A value indicating whether source maps may be emitted for the name.
+     */
+    export function getNamespaceMemberName(ns: Identifier, name: Identifier, allowComments?: boolean, allowSourceMaps?: boolean): PropertyAccessExpression {
+        const qualifiedName = createPropertyAccess(ns, nodeIsSynthesized(name) ? name : getSynthesizedClone(name), /*location*/ name);
+        let emitFlags: EmitFlags;
+        if (!allowSourceMaps) emitFlags |= EmitFlags.NoSourceMap;
+        if (!allowComments) emitFlags |= EmitFlags.NoComments;
+        if (emitFlags) setEmitFlags(qualifiedName, emitFlags);
+        return qualifiedName;
+    }
+
     // Utilities
 
     function isUseStrictPrologue(node: ExpressionStatement): boolean {
diff --git a/src/compiler/transformer.ts b/src/compiler/transformer.ts
index 82e1843b70bbe..08ff4a55a1a65 100644
--- a/src/compiler/transformer.ts
+++ b/src/compiler/transformer.ts
@@ -111,7 +111,10 @@ namespace ts {
         const transformers: Transformer[] = [];
 
         transformers.push(transformTypeScript);
-        transformers.push(moduleTransformerMap[moduleKind] || moduleTransformerMap[ModuleKind.None]);
+
+        if (moduleKind === ModuleKind.System) {
+            transformers.push(moduleTransformerMap[moduleKind] || moduleTransformerMap[ModuleKind.None]);
+        }
 
         if (jsx === JsxEmit.React) {
             transformers.push(transformJsx);
@@ -130,6 +133,10 @@ namespace ts {
             transformers.push(transformGenerators);
         }
 
+        if (moduleKind !== ModuleKind.System) {
+            transformers.push(moduleTransformerMap[moduleKind] || moduleTransformerMap[ModuleKind.None]);
+        }
+
         if (languageVersion < ScriptTarget.ES5) {
             transformers.push(transformES5);
         }
diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
index 22203876df400..8d158cd665eb5 100644
--- a/src/compiler/transformers/es2015.ts
+++ b/src/compiler/transformers/es2015.ts
@@ -308,8 +308,8 @@ namespace ts {
 
         function visitJavaScript(node: Node): VisitResult<Node> {
             switch (node.kind) {
-                case SyntaxKind.ExportKeyword:
-                    return node;
+                case SyntaxKind.StaticKeyword:
+                    return undefined; // elide static keyword
 
                 case SyntaxKind.ClassDeclaration:
                     return visitClassDeclaration(<ClassDeclaration>node);
@@ -584,47 +584,41 @@ namespace ts {
             //          return C;
             //      }());
 
-            const modifierFlags = getModifierFlags(node);
-            const isExported = modifierFlags & ModifierFlags.Export;
-            const isDefault = modifierFlags & ModifierFlags.Default;
+            const variable = createVariableDeclaration(
+                getDeclarationName(node, /*allowComments*/ true),
+                /*type*/ undefined,
+                transformClassLikeDeclarationToExpression(node)
+            );
 
-            // Add an `export` modifier to the statement if needed (for `--target es5 --module es6`)
-            const modifiers = isExported && !isDefault
-                ? filter(node.modifiers, isExportModifier)
-                : undefined;
+            setOriginalNode(variable, node);
 
-            const statement = createVariableStatement(
-                modifiers,
-                createVariableDeclarationList([
-                    createVariableDeclaration(
-                        getDeclarationName(node, /*allowComments*/ true),
-                        /*type*/ undefined,
-                        transformClassLikeDeclarationToExpression(node)
-                    )
-                ]),
-                /*location*/ node
-            );
+            const statements: Statement[] = [];
+            const statement = createVariableStatement(/*modifiers*/ undefined, createVariableDeclarationList([variable]), /*location*/ node);
 
             setOriginalNode(statement, node);
             startOnNewLine(statement);
+            statements.push(statement);
 
             // Add an `export default` statement for default exports (for `--target es5 --module es6`)
-            if (isExported && isDefault) {
-                const statements: Statement[] = [statement];
-                statements.push(createExportAssignment(
-                    /*decorators*/ undefined,
-                    /*modifiers*/ undefined,
-                    /*isExportEquals*/ false,
-                    getDeclarationName(node, /*allowComments*/ false)
-                ));
-                return statements;
+            if (hasModifier(node, ModifierFlags.Export)) {
+                if (hasModifier(node, ModifierFlags.Default)) {
+                    const exportStatement = createExportDefault(getLocalName(node));
+                    setOriginalNode(exportStatement, statement);
+                    statements.push(exportStatement);
+                }
+                else {
+                    statements.push(createExternalModuleExport(getLocalName(node)));
+                }
             }
 
-            return statement;
-        }
+            const emitFlags = getEmitFlags(node);
+            if ((emitFlags & EmitFlags.HasEndOfDeclarationMarker) === 0) {
+                // Add a DeclarationMarker as a marker for the end of the declaration
+                statements.push(createEndOfDeclarationMarker(node));
+                setEmitFlags(statement, emitFlags | EmitFlags.HasEndOfDeclarationMarker);
+            }
 
-        function isExportModifier(node: Modifier) {
-            return node.kind === SyntaxKind.ExportKeyword;
+            return singleOrMany(statements);
         }
 
         /**
@@ -1984,13 +1978,16 @@ namespace ts {
                     statements.push(
                         createVariableStatement(
                             /*modifiers*/ undefined,
-                            createVariableDeclarationList([
-                                createVariableDeclaration(
-                                    firstOriginalDeclaration ? firstOriginalDeclaration.name : createTempVariable(/*recordTempVariable*/ undefined),
-                                    /*type*/ undefined,
-                                    createElementAccess(rhsReference, counter)
-                                )
-                            ], /*location*/ moveRangePos(initializer, -1)),
+                            setOriginalNode(
+                                createVariableDeclarationList([
+                                    createVariableDeclaration(
+                                        firstOriginalDeclaration ? firstOriginalDeclaration.name : createTempVariable(/*recordTempVariable*/ undefined),
+                                        /*type*/ undefined,
+                                        createElementAccess(rhsReference, counter)
+                                    )
+                                ], /*location*/ moveRangePos(initializer, -1)),
+                                initializer
+                            ),
                             /*location*/ moveRangeEnd(initializer, -1)
                         )
                     );
@@ -2052,10 +2049,13 @@ namespace ts {
             setEmitFlags(body, EmitFlags.NoSourceMap | EmitFlags.NoTokenSourceMaps);
 
             const forStatement = createFor(
-                createVariableDeclarationList([
-                    createVariableDeclaration(counter, /*type*/ undefined, createLiteral(0), /*location*/ moveRangePos(node.expression, -1)),
-                    createVariableDeclaration(rhsReference, /*type*/ undefined, expression, /*location*/ node.expression)
-                ], /*location*/ node.expression),
+                setEmitFlags(
+                    createVariableDeclarationList([
+                        createVariableDeclaration(counter, /*type*/ undefined, createLiteral(0), /*location*/ moveRangePos(node.expression, -1)),
+                        createVariableDeclaration(rhsReference, /*type*/ undefined, expression, /*location*/ node.expression)
+                    ], /*location*/ node.expression),
+                    EmitFlags.NoHoisting
+                ),
                 createLessThan(
                     counter,
                     createPropertyAccess(rhsReference, "length"),
@@ -2247,25 +2247,28 @@ namespace ts {
             const convertedLoopVariable =
                 createVariableStatement(
                     /*modifiers*/ undefined,
-                    createVariableDeclarationList(
-                        [
-                            createVariableDeclaration(
-                                functionName,
-                                /*type*/ undefined,
-                                setEmitFlags(
-                                    createFunctionExpression(
-                                        /*modifiers*/ undefined,
-                                        isAsyncBlockContainingAwait ? createToken(SyntaxKind.AsteriskToken) : undefined,
-                                        /*name*/ undefined,
-                                        /*typeParameters*/ undefined,
-                                        loopParameters,
-                                        /*type*/ undefined,
-                                        <Block>loopBody
-                                    ),
-                                    loopBodyFlags
+                    setEmitFlags(
+                        createVariableDeclarationList(
+                            [
+                                createVariableDeclaration(
+                                    functionName,
+                                    /*type*/ undefined,
+                                    setEmitFlags(
+                                        createFunctionExpression(
+                                            /*modifiers*/ undefined,
+                                            isAsyncBlockContainingAwait ? createToken(SyntaxKind.AsteriskToken) : undefined,
+                                            /*name*/ undefined,
+                                            /*typeParameters*/ undefined,
+                                            loopParameters,
+                                            /*type*/ undefined,
+                                            <Block>loopBody
+                                        ),
+                                        loopBodyFlags
+                                    )
                                 )
-                            )
-                        ]
+                            ]
+                        ),
+                        EmitFlags.NoHoisting
                     )
                 );
 
@@ -3192,45 +3195,6 @@ namespace ts {
             return node;
         }
 
-        /**
-         * Gets the local name for a declaration for use in expressions.
-         *
-         * A local name will *never* be prefixed with an module or namespace export modifier like
-         * "exports.".
-         *
-         * @param node The declaration.
-         * @param allowComments A value indicating whether comments may be emitted for the name.
-         * @param allowSourceMaps A value indicating whether source maps may be emitted for the name.
-         */
-        function getLocalName(node: ClassDeclaration | ClassExpression | FunctionDeclaration, allowComments?: boolean, allowSourceMaps?: boolean) {
-            return getDeclarationName(node, allowComments, allowSourceMaps, EmitFlags.LocalName);
-        }
-
-        /**
-         * Gets the name of a declaration, without source map or comments.
-         *
-         * @param node The declaration.
-         * @param allowComments Allow comments for the name.
-         */
-        function getDeclarationName(node: ClassDeclaration | ClassExpression | FunctionDeclaration, allowComments?: boolean, allowSourceMaps?: boolean, emitFlags?: EmitFlags) {
-            if (node.name && !isGeneratedIdentifier(node.name)) {
-                const name = getMutableClone(node.name);
-                emitFlags |= getEmitFlags(node.name);
-                if (!allowSourceMaps) {
-                    emitFlags |= EmitFlags.NoSourceMap;
-                }
-                if (!allowComments) {
-                    emitFlags |= EmitFlags.NoComments;
-                }
-                if (emitFlags) {
-                    setEmitFlags(name, emitFlags);
-                }
-                return name;
-            }
-
-            return getGeneratedNameForNode(node);
-        }
-
         function getClassMemberPrefix(node: ClassExpression | ClassDeclaration, member: ClassElement) {
             const expression = getLocalName(node);
             return hasModifier(member, ModifierFlags.Static) ? expression : createPropertyAccess(expression, "prototype");
diff --git a/src/compiler/transformers/module/module.ts b/src/compiler/transformers/module/module.ts
index 51b03b43c94da..2d8a513cc8845 100644
--- a/src/compiler/transformers/module/module.ts
+++ b/src/compiler/transformers/module/module.ts
@@ -26,22 +26,19 @@ namespace ts {
         const previousOnEmitNode = context.onEmitNode;
         context.onSubstituteNode = onSubstituteNode;
         context.onEmitNode = onEmitNode;
-        context.enableSubstitution(SyntaxKind.Identifier);
-        context.enableSubstitution(SyntaxKind.BinaryExpression);
-        context.enableSubstitution(SyntaxKind.PrefixUnaryExpression);
-        context.enableSubstitution(SyntaxKind.PostfixUnaryExpression);
-        context.enableSubstitution(SyntaxKind.ShorthandPropertyAssignment);
-        context.enableEmitNotification(SyntaxKind.SourceFile);
-
-        let currentSourceFile: SourceFile;
-        let externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[];
-        let exportSpecifiers: Map<ExportSpecifier[]>;
-        let exportEquals: ExportAssignment;
-        let bindingNameExportSpecifiersMap: Map<ExportSpecifier[]>;
-        // Subset of exportSpecifiers that is a binding-name.
-        // This is to reduce amount of memory we have to keep around even after we done with module-transformer
-        const bindingNameExportSpecifiersForFileMap = createMap<Map<ExportSpecifier[]>>();
-        let hasExportStarsToExportValues: boolean;
+        context.enableSubstitution(SyntaxKind.Identifier); // Substitutes expression identifiers with imported/exported symbols.
+        context.enableSubstitution(SyntaxKind.BinaryExpression); // Substitutes assignments to exported symbols.
+        context.enableSubstitution(SyntaxKind.PrefixUnaryExpression); // Substitutes updates to exported symbols.
+        context.enableSubstitution(SyntaxKind.PostfixUnaryExpression); // Substitutes updates to exported symbols.
+        context.enableSubstitution(SyntaxKind.ShorthandPropertyAssignment); // Substitutes shorthand property assignments for imported/exported symbols.
+        context.enableEmitNotification(SyntaxKind.SourceFile); // Restore state when substituting nodes in a file.
+
+        const moduleInfoMap = createMap<ExternalModuleInfo>(); // The ExternalModuleInfo for each file.
+        const deferredExports = createMap<Statement[]>(); // Exports to defer until an EndOfDeclarationMarker is found.
+
+        let currentSourceFile: SourceFile; // The current file.
+        let currentModuleInfo: ExternalModuleInfo; // The ExternalModuleInfo for the current file.
+        let noSubstitution: Map<boolean>; // Set of nodes for which substitution rules should be ignored.
 
         return transformSourceFile;
 
@@ -57,9 +54,7 @@ namespace ts {
 
             if (isExternalModule(node) || compilerOptions.isolatedModules) {
                 currentSourceFile = node;
-
-                // Collect information about the external module.
-                ({ externalImports, exportSpecifiers, exportEquals, hasExportStarsToExportValues } = collectExternalModuleInfo(node));
+                currentModuleInfo = moduleInfoMap[getOriginalNodeId(node)] = collectExternalModuleInfo(node, resolver);
 
                 // Perform the transformation.
                 const transformModule = transformModuleDelegates[moduleKind] || transformModuleDelegates[ModuleKind.None];
@@ -67,10 +62,7 @@ namespace ts {
                 aggregateTransformFlags(updated);
 
                 currentSourceFile = undefined;
-                externalImports = undefined;
-                exportSpecifiers = undefined;
-                exportEquals = undefined;
-                hasExportStarsToExportValues = false;
+                currentModuleInfo = undefined;
                 return updated;
             }
 
@@ -92,7 +84,7 @@ namespace ts {
             addExportEqualsIfNeeded(statements, /*emitAsReturn*/ false);
 
             const updated = updateSourceFileNode(node, createNodeArray(statements, node.statements));
-            if (hasExportStarsToExportValues) {
+            if (currentModuleInfo.hasExportStarsToExportValues) {
                 setEmitFlags(updated, EmitFlags.EmitExportStar | getEmitFlags(node));
             }
 
@@ -158,43 +150,43 @@ namespace ts {
             //     define(moduleName?, ["module1", "module2"], function ...
             return updateSourceFileNode(node, createNodeArray(
                 [
-                createStatement(
-                    createCall(
-                        define,
-                        /*typeArguments*/ undefined,
-                        [
-                            // Add the module name (if provided).
-                            ...(moduleName ? [moduleName] : []),
-
-                            // Add the dependency array argument:
-                            //
-                            //     ["require", "exports", module1", "module2", ...]
-                            createArrayLiteral([
-                                createLiteral("require"),
-                                createLiteral("exports"),
-                                ...aliasedModuleNames,
-                                ...unaliasedModuleNames
-                            ]),
-
-                            // Add the module body function argument:
-                            //
-                            //     function (require, exports, module1, module2) ...
-                            createFunctionExpression(
-                                /*modifiers*/ undefined,
-                                /*asteriskToken*/ undefined,
-                                /*name*/ undefined,
-                                /*typeParameters*/ undefined,
-                                [
+                    createStatement(
+                        createCall(
+                            define,
+                            /*typeArguments*/ undefined,
+                            [
+                                // Add the module name (if provided).
+                                ...(moduleName ? [moduleName] : []),
+
+                                // Add the dependency array argument:
+                                //
+                                //     ["require", "exports", module1", "module2", ...]
+                                createArrayLiteral([
+                                    createLiteral("require"),
+                                    createLiteral("exports"),
+                                    ...aliasedModuleNames,
+                                    ...unaliasedModuleNames
+                                ]),
+
+                                // Add the module body function argument:
+                                //
+                                //     function (require, exports, module1, module2) ...
+                                createFunctionExpression(
+                                    /*modifiers*/ undefined,
+                                    /*asteriskToken*/ undefined,
+                                    /*name*/ undefined,
+                                    /*typeParameters*/ undefined,
+                                    [
                                         createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "require"),
                                         createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, "exports"),
-                                    ...importAliasNames
-                                ],
-                                /*type*/ undefined,
-                                transformAsynchronousModuleBody(node)
-                            )
-                        ]
+                                        ...importAliasNames
+                                    ],
+                                    /*type*/ undefined,
+                                    transformAsynchronousModuleBody(node)
+                                )
+                            ]
+                        )
                     )
-                )
                 ],
                 /*location*/ node.statements)
             );
@@ -222,7 +214,7 @@ namespace ts {
             addExportEqualsIfNeeded(statements, /*emitAsReturn*/ true);
 
             const body = createBlock(statements, /*location*/ undefined, /*multiLine*/ true);
-            if (hasExportStarsToExportValues) {
+            if (currentModuleInfo.hasExportStarsToExportValues) {
                 // If we have any `export * from ...` declarations
                 // we need to inform the emitter to add the __export helper.
                 setEmitFlags(body, EmitFlags.EmitExportStar);
@@ -231,35 +223,6 @@ namespace ts {
             return body;
         }
 
-        function addExportEqualsIfNeeded(statements: Statement[], emitAsReturn: boolean) {
-            if (exportEquals) {
-                if (emitAsReturn) {
-                    const statement = createReturn(
-                        exportEquals.expression,
-                        /*location*/ exportEquals
-                    );
-
-                    setEmitFlags(statement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoComments);
-                    statements.push(statement);
-                }
-                else {
-                    const statement = createStatement(
-                        createAssignment(
-                            createPropertyAccess(
-                                createIdentifier("module"),
-                                "exports"
-                            ),
-                            exportEquals.expression
-                        ),
-                        /*location*/ exportEquals
-                    );
-
-                    setEmitFlags(statement, EmitFlags.NoComments);
-                    statements.push(statement);
-                }
-            }
-        }
-
         /**
          * Visits a node at the top level of the source file.
          *
@@ -288,8 +251,11 @@ namespace ts {
                 case SyntaxKind.ClassDeclaration:
                     return visitClassDeclaration(<ClassDeclaration>node);
 
-                case SyntaxKind.ExpressionStatement:
-                    return visitExpressionStatement(<ExpressionStatement>node);
+                case SyntaxKind.NotEmittedStatement:
+                    return visitNotEmittedStatement(<NotEmittedStatement>node);
+
+                case SyntaxKind.EndOfDeclarationMarker:
+                    return visitEndOfDeclarationMarker(<EndOfDeclarationMarker>node);
 
                 default:
                     // This visitor does not descend into the tree, as export/import statements
@@ -299,26 +265,33 @@ namespace ts {
         }
 
         /**
-         * Visits an ImportDeclaration node.
+         * Visits a modifier.
          *
-         * @param node The ImportDeclaration node.
+         * @param node The modifier.
          */
-        function visitImportDeclaration(node: ImportDeclaration): VisitResult<Statement> {
-            if (!contains(externalImports, node)) {
-                return undefined;
+        function modifierVisitor(node: Node): VisitResult<Node> {
+            // Elide module-specific modifiers.
+            switch (node.kind) {
+                case SyntaxKind.ExportKeyword:
+                case SyntaxKind.DefaultKeyword:
+                    return undefined;
             }
 
-            const statements: Statement[] = [];
+            return node;
+        }
+
+        /**
+         * Visits an ImportDeclaration node.
+         *
+         * @param node The ImportDeclaration node
+         */
+        function visitImportDeclaration(node: ImportDeclaration): VisitResult<Statement> {
+            let statements: Statement[];
             const namespaceDeclaration = getNamespaceDeclarationNode(node);
             if (moduleKind !== ModuleKind.AMD) {
                 if (!node.importClause) {
                     // import "mod";
-                    statements.push(
-                        createStatement(
-                            createRequireCall(node),
-                            /*location*/ node
-                        )
-                    );
+                    return createStatement(createRequireCall(node), /*location*/ node);
                 }
                 else {
                     const variables: VariableDeclaration[] = [];
@@ -356,10 +329,14 @@ namespace ts {
                         }
                     }
 
-                    statements.push(
+                    statements = append(statements,
                         createVariableStatement(
                             /*modifiers*/ undefined,
-                            createConstDeclarationList(variables),
+                            createVariableDeclarationList(
+                                variables,
+                                /*location*/ undefined,
+                                languageVersion >= ScriptTarget.ES2015 ? NodeFlags.Const : NodeFlags.None
+                            ),
                             /*location*/ node
                         )
                     );
@@ -367,37 +344,41 @@ namespace ts {
             }
             else if (namespaceDeclaration && isDefaultImport(node)) {
                 // import d, * as n from "mod";
-                statements.push(
+                statements = append(statements,
                     createVariableStatement(
                         /*modifiers*/ undefined,
-                        createVariableDeclarationList([
-                            createVariableDeclaration(
-                                getSynthesizedClone(namespaceDeclaration.name),
-                                /*type*/ undefined,
-                                getGeneratedNameForNode(node),
-                                /*location*/ node
-                            )
-                        ])
+                        createVariableDeclarationList(
+                            [
+                                createVariableDeclaration(
+                                    getSynthesizedClone(namespaceDeclaration.name),
+                                    /*type*/ undefined,
+                                    getGeneratedNameForNode(node),
+                                    /*location*/ node
+                                )
+                            ],
+                            /*location*/ undefined,
+                            languageVersion >= ScriptTarget.ES2015 ? NodeFlags.Const : NodeFlags.None
+                        )
                     )
                 );
             }
 
-            addExportImportAssignments(statements, node);
+            statements = appendExportsOfImportDeclaration(statements, node);
             return singleOrMany(statements);
         }
 
+        /**
+         * Visits an ImportEqualsDeclaration node.
+         *
+         * @param node The ImportEqualsDeclaration node
+         */
         function visitImportEqualsDeclaration(node: ImportEqualsDeclaration): VisitResult<Statement> {
-            if (!contains(externalImports, node)) {
-                return undefined;
-            }
+            Debug.assert(isExternalModuleImportEqualsDeclaration(node), "import= for internal module references should be handled in an earlier transformer.");
 
-            // Set emitFlags on the name of the importEqualsDeclaration
-            // This is so the printer will not substitute the identifier
-            setEmitFlags(node.name, EmitFlags.NoSubstitution);
-            const statements: Statement[] = [];
+            let statements: Statement[];
             if (moduleKind !== ModuleKind.AMD) {
                 if (hasModifier(node, ModifierFlags.Export)) {
-                    statements.push(
+                    statements = append(statements,
                         createStatement(
                             createExportAssignment(
                                 node.name,
@@ -408,18 +389,20 @@ namespace ts {
                     );
                 }
                 else {
-                    statements.push(
+                    statements = append(statements,
                         createVariableStatement(
                             /*modifiers*/ undefined,
-                            createVariableDeclarationList([
-                                createVariableDeclaration(
-                                    getSynthesizedClone(node.name),
-                                    /*type*/ undefined,
-                                    createRequireCall(node)
-                                )
-                            ],
-                            /*location*/ undefined,
-                            /*flags*/ languageVersion >= ScriptTarget.ES2015 ? NodeFlags.Const : NodeFlags.None),
+                            createVariableDeclarationList(
+                                [
+                                    createVariableDeclaration(
+                                        getSynthesizedClone(node.name),
+                                        /*type*/ undefined,
+                                        createRequireCall(node)
+                                    )
+                                ],
+                                /*location*/ undefined,
+                                /*flags*/ languageVersion >= ScriptTarget.ES2015 ? NodeFlags.Const : NodeFlags.None
+                            ),
                             /*location*/ node
                         )
                     );
@@ -427,21 +410,35 @@ namespace ts {
             }
             else {
                 if (hasModifier(node, ModifierFlags.Export)) {
-                    statements.push(
+                    statements = append(statements,
                         createStatement(
-                            createExportAssignment(node.name, node.name),
+                            createExportAssignment(getExportName(node), getLocalName(node)),
                             /*location*/ node
                         )
                     );
                 }
             }
 
-            addExportImportAssignments(statements, node);
-            return statements;
+            if (hasAssociatedEndOfDeclarationMarker(node)) {
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportsOfImportEqualsDeclaration(deferredExports[id], node);
+            }
+            else {
+                statements = appendExportsOfImportEqualsDeclaration(statements, node);
+            }
+
+            return singleOrMany(statements);
         }
 
+        /**
+         * Visits an ExportDeclaration node.
+         *
+         * @param The ExportDeclaration node
+         */
         function visitExportDeclaration(node: ExportDeclaration): VisitResult<Statement> {
-            if (!contains(externalImports, node)) {
+            if (!node.moduleSpecifier) {
+                // Elide export declarations with no module specifier as they are handled
+                // elsewhere.
                 return undefined;
             }
 
@@ -471,7 +468,7 @@ namespace ts {
                     );
                     statements.push(
                         createStatement(
-                            createExportAssignment(specifier.name, exportedValue),
+                            createExportAssignment(getExportName(specifier), exportedValue),
                             /*location*/ specifier
                         )
                     );
@@ -496,189 +493,87 @@ namespace ts {
             }
         }
 
+        /**
+         * Visits an ExportAssignment node.
+         *
+         * @param node The ExportAssignment node
+         */
         function visitExportAssignment(node: ExportAssignment): VisitResult<Statement> {
             if (node.isExportEquals) {
-                // Elide as `export=` is handled in addExportEqualsIfNeeded
                 return undefined;
             }
 
-            const statements: Statement[] = [];
-            addExportDefault(statements, node.expression, /*location*/ node);
-            return statements;
-        }
-
-        function addExportDefault(statements: Statement[], expression: Expression, location: TextRange): void {
-            tryAddExportDefaultCompat(statements);
-
-            statements.push(
-                createStatement(
-                    createExportAssignment(
-                        createIdentifier("default"),
-                        expression
-                    ),
-                    location
-                )
-            );
-        }
-
-        function tryAddExportDefaultCompat(statements: Statement[]) {
-            const original = getOriginalNode(currentSourceFile);
-            Debug.assert(original.kind === SyntaxKind.SourceFile);
-
-            if (!original.symbol.exports["___esModule"]) {
-                if (languageVersion === ScriptTarget.ES3) {
-                    statements.push(
-                        createStatement(
-                            createExportAssignment(
-                                createIdentifier("__esModule"),
-                                createLiteral(true)
-                            )
-                        )
-                    );
-                }
-                else {
-                    statements.push(
-                        createStatement(
-                            createCall(
-                                createPropertyAccess(createIdentifier("Object"), "defineProperty"),
-                                /*typeArguments*/ undefined,
-                                [
-                                    createIdentifier("exports"),
-                                    createLiteral("__esModule"),
-                                    createObjectLiteral([
-                                        createPropertyAssignment("value", createLiteral(true))
-                                    ])
-                                ]
-                            )
-                        )
-                    );
-                }
-            }
-        }
-
-        function addExportImportAssignments(statements: Statement[], node: ImportEqualsDeclaration | ImportDeclaration) {
-            if (isImportEqualsDeclaration(node)) {
-                addExportMemberAssignments(statements, node.name);
+            let statements: Statement[];
+            const original = node.original;
+            if (original && hasAssociatedEndOfDeclarationMarker(original)) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportStatement(deferredExports[id], createIdentifier("default"), node.expression, /*location*/ node, /*allowComments*/ true);
             }
             else {
-                const names = reduceEachChild(node, collectExportMembers, []);
-                for (const name of names) {
-                    addExportMemberAssignments(statements, name);
-                }
+                statements = appendExportStatement(statements, createIdentifier("default"), node.expression, /*location*/ node, /*allowComments*/ true);
             }
-        }
 
-        function collectExportMembers(names: Identifier[], node: Node): Identifier[] {
-            if (isAliasSymbolDeclaration(node) && isDeclaration(node)) {
-                const name = node.name;
-                if (isIdentifier(name)) {
-                    names.push(name);
-                }
-            }
-
-            return reduceEachChild(node, collectExportMembers, names);
-        }
-
-        function addExportMemberAssignments(statements: Statement[], name: Identifier): void {
-            if (!exportEquals && exportSpecifiers && hasProperty(exportSpecifiers, name.text)) {
-                for (const specifier of exportSpecifiers[name.text]) {
-                    statements.push(
-                        startOnNewLine(
-                            createStatement(
-                                createExportAssignment(specifier.name, name),
-                                /*location*/ specifier.name
-                            )
-                        )
-                    );
-                }
-            }
-        }
-
-        function addExportMemberAssignment(statements: Statement[], node: DeclarationStatement) {
-            if (hasModifier(node, ModifierFlags.Default)) {
-                addExportDefault(statements, getDeclarationName(node), /*location*/ node);
-            }
-            else {
-                statements.push(
-                    createExportStatement(<Identifier>node.name, setEmitFlags(getSynthesizedClone(node.name), EmitFlags.LocalName), /*location*/ node)
-                );
-            }
+            return singleOrMany(statements);
         }
 
+        /**
+         * Visits a VariableStatement.
+         *
+         * @param node A VariableStatement node.
+         */
         function visitVariableStatement(node: VariableStatement): VisitResult<Statement> {
-            // If the variable is for a generated declaration,
-            // we should maintain it and just strip off the 'export' modifier if necessary.
-            const originalKind = getOriginalNode(node).kind;
-            if (originalKind === SyntaxKind.ModuleDeclaration ||
-                originalKind === SyntaxKind.EnumDeclaration ||
-                originalKind === SyntaxKind.ClassDeclaration) {
-
-                if (!hasModifier(node, ModifierFlags.Export)) {
-                    return node;
-                }
+            let statements: Statement[];
+            let variables: VariableDeclaration[];
+            let expressions: Expression[];
+            if (hasModifier(node, ModifierFlags.Export)) {
+                let modifiers: NodeArray<Modifier>;
+
+                // If we're exporting these variables, then these just become assignments to 'exports.x'.
+                // We only want to emit assignments for variables with initializers.
+                for (const variable of node.declarationList.declarations) {
+                    if (isIdentifier(variable.name) && isLocalName(variable.name)) {
+                        if (!modifiers) {
+                            modifiers = visitNodes(node.modifiers, modifierVisitor, isModifier);
+                        }
 
-                return setOriginalNode(
-                    createVariableStatement(
-                        /*modifiers*/ undefined,
-                        node.declarationList
-                    ),
-                    node
-                );
-            }
+                        variables = append(variables, variable);
+                    }
+                    else if (variable.initializer) {
+                        expressions = append(expressions, transformInitializedVariable(variable));
+                    }
+                }
 
-            const resultStatements: Statement[] = [];
+                if (variables) {
+                    statements = append(statements, updateVariableStatement(node, modifiers, updateVariableDeclarationList(node.declarationList, variables)));
+                }
 
-            // If we're exporting these variables, then these just become assignments to 'exports.blah'.
-            // We only want to emit assignments for variables with initializers.
-            if (hasModifier(node, ModifierFlags.Export)) {
-                const variables = getInitializedVariables(node.declarationList);
-                if (variables.length > 0) {
-                    const inlineAssignments = createStatement(
-                        inlineExpressions(
-                            map(variables, transformInitializedVariable)
-                        ),
-                        node
-                    );
-                    resultStatements.push(inlineAssignments);
+                if (expressions) {
+                    statements = append(statements, createStatement(inlineExpressions(expressions), /*location*/ node));
                 }
             }
             else {
-                resultStatements.push(node);
+                statements = append(statements, node);
             }
 
-            // While we might not have been exported here, each variable might have been exported
-            // later on in an export specifier (e.g. `export {foo as blah, bar}`).
-            for (const decl of node.declarationList.declarations) {
-                addExportMemberAssignmentsForBindingName(resultStatements, decl.name);
+            if (hasAssociatedEndOfDeclarationMarker(node)) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], node);
+            }
+            else {
+                statements = appendExportsOfVariableStatement(statements, node);
             }
 
-            return resultStatements;
+            // statements = addExportsOfVariableStatement(statements, node);
+            return singleOrMany(statements);
         }
 
         /**
-         * Creates appropriate assignments for each binding identifier that is exported in an export specifier,
-         * and inserts it into 'resultStatements'.
+         * Transforms an exported variable with an initializer into an expression.
+         *
+         * @param node The variable to transform.
          */
-        function addExportMemberAssignmentsForBindingName(resultStatements: Statement[], name: BindingName): void {
-            if (isBindingPattern(name)) {
-                for (const element of name.elements) {
-                    if (!isOmittedExpression(element)) {
-                        addExportMemberAssignmentsForBindingName(resultStatements, element.name);
-                    }
-                }
-            }
-            else {
-                if (!exportEquals && exportSpecifiers && hasProperty(exportSpecifiers, name.text)) {
-                    const sourceFileId = getOriginalNodeId(currentSourceFile);
-                    if (!bindingNameExportSpecifiersForFileMap[sourceFileId]) {
-                        bindingNameExportSpecifiersForFileMap[sourceFileId] = createMap<ExportSpecifier[]>();
-                    }
-                    bindingNameExportSpecifiersForFileMap[sourceFileId][name.text] = exportSpecifiers[name.text];
-                    addExportMemberAssignments(resultStatements, name);
-                }
-            }
-        }
-
         function transformInitializedVariable(node: VariableDeclaration): Expression {
             const name = node.name;
             if (isBindingPattern(name)) {
@@ -686,31 +581,32 @@ namespace ts {
                     context,
                     node,
                     hoistVariableDeclaration,
-                    getModuleMemberName,
-                    visitor
+                    getModuleMemberName
                 );
             }
             else {
                 return createAssignment(
                     getModuleMemberName(name),
-                    visitNode(node.initializer, visitor, isExpression)
+                    node.initializer
                 );
             }
         }
 
+        /**
+         * Visits a FunctionDeclaration.
+         *
+         * @param node A FunctionDeclaration node.
+         */
         function visitFunctionDeclaration(node: FunctionDeclaration): VisitResult<Statement> {
-            const statements: Statement[] = [];
-            const name = node.name || getGeneratedNameForNode(node);
+            let statements: Statement[];
             if (hasModifier(node, ModifierFlags.Export)) {
-                // Keep async modifier for ES2017 transformer
-                const isAsync = hasModifier(node, ModifierFlags.Async);
-                statements.push(
+                statements = append(statements,
                     setOriginalNode(
                         createFunctionDeclaration(
                             /*decorators*/ undefined,
-                            isAsync ? [<Modifier>createNode(SyntaxKind.AsyncKeyword)] : undefined,
+                            visitNodes(node.modifiers, modifierVisitor, isModifier),
                             node.asteriskToken,
-                            name,
+                            getDeclarationName(node, /*allowComments*/ true, /*allowSourceMaps*/ true),
                             /*typeParameters*/ undefined,
                             node.parameters,
                             /*type*/ undefined,
@@ -720,30 +616,37 @@ namespace ts {
                         /*original*/ node
                     )
                 );
-
-                addExportMemberAssignment(statements, node);
             }
             else {
-                statements.push(node);
+                statements = append(statements, node);
             }
 
-            if (node.name) {
-                addExportMemberAssignments(statements, node.name);
+            if (hasAssociatedEndOfDeclarationMarker(node)) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportsOfHoistedDeclaration(deferredExports[id], node);
+            }
+            else {
+                statements = appendExportsOfHoistedDeclaration(statements, node);
             }
 
             return singleOrMany(statements);
         }
 
+        /**
+         * Visits a ClassDeclaration.
+         *
+         * @param node A ClassDeclaration node.
+         */
         function visitClassDeclaration(node: ClassDeclaration): VisitResult<Statement> {
-            const statements: Statement[] = [];
-            const name = node.name || getGeneratedNameForNode(node);
+            let statements: Statement[];
             if (hasModifier(node, ModifierFlags.Export)) {
-                statements.push(
+                statements = append(statements,
                     setOriginalNode(
                         createClassDeclaration(
                             /*decorators*/ undefined,
-                            /*modifiers*/ undefined,
-                            name,
+                            visitNodes(node.modifiers, modifierVisitor, isModifier),
+                            getDeclarationName(node, /*allowComments*/ true, /*allowSourceMaps*/ true),
                             /*typeParameters*/ undefined,
                             node.heritageClauses,
                             node.members,
@@ -752,78 +655,333 @@ namespace ts {
                         /*original*/ node
                     )
                 );
-
-                addExportMemberAssignment(statements, node);
             }
             else {
-                statements.push(node);
+                statements = append(statements, node);
             }
 
-            // Decorators end up creating a series of assignment expressions which overwrite
-            // the local binding that we export, so we need to defer from exporting decorated classes
-            // until the decoration assignments take place. We do this when visiting expression-statements.
-            if (node.name && !(node.decorators && node.decorators.length)) {
-                addExportMemberAssignments(statements, node.name);
+            if (hasAssociatedEndOfDeclarationMarker(node)) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportsOfHoistedDeclaration(deferredExports[id], node);
+            }
+            else {
+                statements = appendExportsOfHoistedDeclaration(statements, node);
             }
 
             return singleOrMany(statements);
         }
 
-        function visitExpressionStatement(node: ExpressionStatement): VisitResult<Statement> {
-            const original = getOriginalNode(node);
-            const origKind = original.kind;
+        /**
+         * Visits a NotEmittedStatement.
+         *
+         * @param node A NotEmittedStatement node.
+         */
+        function visitNotEmittedStatement(node: NotEmittedStatement): VisitResult<Statement> {
+            // For an EnumDeclaration or ModuleDeclaration that merges with a preceeding
+            // declaration we do not emit a leading variable declaration. To preserve the
+            // begin/end semantics of the declararation and to properly handle exports
+            // we wrap the leading variable declaration in a `NotEmittedStatement`.
+            //
+            // To balance the declaration, add the exports of the elided variable
+            // statement.
+            if (hasAssociatedEndOfDeclarationMarker(node.original) && node.original.kind === SyntaxKind.VariableStatement) {
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], <VariableStatement>node.original);
+            }
+
+            return node;
+        }
+
+        /**
+         * Visits a DeclarationMarker used as a placeholder for the end of a transformed declaration.
+         *
+         * @param node A DeclarationMarker node.
+         */
+        function visitEndOfDeclarationMarker(node: EndOfDeclarationMarker): VisitResult<Statement> {
+            // For some transformations we emit an `EndOfDeclarationMarker` to mark the actual
+            // end of the transformed declaration. We use this marker to emit any deferred exports
+            // of the declaration.
+            const id = getOriginalNodeId(node);
+            const statements = deferredExports[id];
+            if (statements) {
+                delete deferredExports[id];
+                return append(statements, node);
+            }
+
+            return node;
+        }
 
-            if (origKind === SyntaxKind.EnumDeclaration || origKind === SyntaxKind.ModuleDeclaration) {
-                return visitExpressionStatementForEnumOrNamespaceDeclaration(node, <EnumDeclaration | ModuleDeclaration>original);
+        /**
+         * Appends the exports of an ImportDeclaration to a statement list, returning the
+         * statement list.
+         *
+         * If `statements` is `undefined`, a new array is allocated if statements are appended.
+         *
+         * @param statements A statement list to which the down-level export statements are to be
+         *  appended.
+         * @param decl The declaration whose exports are to be recorded.
+         */
+        function appendExportsOfImportDeclaration(statements: Statement[] | undefined, decl: ImportDeclaration): Statement[] | undefined {
+            if (currentModuleInfo.exportEquals) {
+                return statements;
             }
-            else if (origKind === SyntaxKind.ClassDeclaration) {
-                // The decorated assignment for a class name may need to be transformed.
-                const classDecl = original as ClassDeclaration;
-                if (classDecl.name) {
-                    const statements = [node];
-                    addExportMemberAssignments(statements, classDecl.name);
-                    return statements;
+
+            const importClause = decl.importClause;
+            if (importClause) {
+                if (importClause.name) {
+                    statements = appendExportsOfDeclaration(statements, importClause);
+                }
+
+                const namedBindings = importClause.namedBindings;
+                if (namedBindings) {
+                    switch (namedBindings.kind) {
+                        case SyntaxKind.NamespaceImport:
+                            statements = appendExportsOfDeclaration(statements, namedBindings);
+                            break;
+
+                        case SyntaxKind.NamedImports:
+                            for (const importBinding of namedBindings.elements) {
+                                statements = appendExportsOfDeclaration(statements, importBinding);
+                            }
+
+                            break;
+                    }
                 }
             }
 
-            return node;
+            return statements;
         }
 
-        function visitExpressionStatementForEnumOrNamespaceDeclaration(node: ExpressionStatement, original: EnumDeclaration | ModuleDeclaration): VisitResult<Statement> {
-            const statements: Statement[] = [node];
+        /**
+         * Appends the exports of an ImportEqualsDeclaration to a statement list, returning the
+         * statement list.
+         *
+         * If `statements` is `undefined`, a new array is allocated if statements are appended.
+         *
+         * @param statements A statement list to which the down-level export statements are to be
+         *  appended.
+         * @param decl The declaration whose exports are to be recorded.
+         */
+        function appendExportsOfImportEqualsDeclaration(statements: Statement[] | undefined, decl: ImportEqualsDeclaration): Statement[] | undefined {
+            if (currentModuleInfo.exportEquals) {
+                return statements;
+            }
 
+            return appendExportsOfDeclaration(statements, decl);
+        }
 
-            addExportMemberAssignments(statements, <Identifier>original.name);
+        /**
+         * Appends the exports of a VariableStatement to a statement list, returning the statement
+         * list.
+         *
+         * If `statements` is `undefined`, a new array is allocated if statements are appended.
+         *
+         * @param statements A statement list to which the down-level export statements are to be
+         *  appended.
+         * @param node The VariableStatement whose exports are to be recorded.
+         */
+        function appendExportsOfVariableStatement(statements: Statement[] | undefined, node: VariableStatement): Statement[] | undefined {
+            if (currentModuleInfo.exportEquals) {
+                return statements;
+            }
+
+            for (const decl of node.declarationList.declarations) {
+                statements = appendExportsOfBindingElement(statements, decl);
+            }
 
             return statements;
         }
 
         /**
-         * Adds a trailing VariableStatement for an enum or module declaration.
+         * Appends the exports of a VariableDeclaration or BindingElement to a statement list,
+         * returning the statement list.
+         *
+         * If `statements` is `undefined`, a new array is allocated if statements are appended.
+         *
+         * @param statements A statement list to which the down-level export statements are to be
+         *  appended.
+         * @param decl The declaration whose exports are to be recorded.
          */
-        function addVarForExportedEnumOrNamespaceDeclaration(statements: Statement[], node: EnumDeclaration | ModuleDeclaration) {
-            const transformedStatement = createVariableStatement(
-                /*modifiers*/ undefined,
-                [createVariableDeclaration(
-                    getDeclarationName(node),
-                        /*type*/ undefined,
-                    createPropertyAccess(createIdentifier("exports"), getDeclarationName(node))
-                )],
-                    /*location*/ node
-            );
-            setEmitFlags(transformedStatement, EmitFlags.NoComments);
-            statements.push(transformedStatement);
+        function appendExportsOfBindingElement(statements: Statement[] | undefined, decl: VariableDeclaration | BindingElement): Statement[] | undefined {
+            if (currentModuleInfo.exportEquals) {
+                return statements;
+            }
+
+            if (isBindingPattern(decl.name)) {
+                for (const element of decl.name.elements) {
+                    if (!isOmittedExpression(element)) {
+                        statements = appendExportsOfBindingElement(statements, element);
+                    }
+                }
+            }
+            else if (!isGeneratedIdentifier(decl.name)) {
+                statements = appendExportsOfDeclaration(statements, decl);
+            }
+
+            return statements;
+        }
+
+        /**
+         * Appends the exports of a ClassDeclaration or FunctionDeclaration to a statement list,
+         * returning the statement list.
+         *
+         * If `statements` is `undefined`, a new array is allocated if statements are appended.
+         *
+         * @param statements A statement list to which the down-level export statements are to be
+         * appended.
+         * @param decl The declaration whose exports are to be recorded.
+         */
+        function appendExportsOfHoistedDeclaration(statements: Statement[] | undefined, decl: ClassDeclaration | FunctionDeclaration): Statement[] | undefined {
+            if (currentModuleInfo.exportEquals) {
+                return statements;
+            }
+
+            if (hasModifier(decl, ModifierFlags.Export)) {
+                const exportName = hasModifier(decl, ModifierFlags.Default) ? createIdentifier("default") : decl.name;
+                statements = appendExportStatement(statements, exportName, getLocalName(decl), /*location*/ decl);
+            }
+
+            if (decl.name) {
+                statements = appendExportsOfDeclaration(statements, decl);
+            }
+
+            return statements;
+        }
+
+        /**
+         * Appends the exports of a declaration to a statement list, returning the statement list.
+         *
+         * If `statements` is `undefined`, a new array is allocated if statements are appended.
+         *
+         * @param statements A statement list to which the down-level export statements are to be
+         *  appended.
+         * @param decl The declaration to export.
+         */
+        function appendExportsOfDeclaration(statements: Statement[] | undefined, decl: Declaration): Statement[] | undefined {
+            const name = getDeclarationName(decl);
+            const exportSpecifiers = currentModuleInfo.exportSpecifiers[name.text];
+            if (exportSpecifiers) {
+                for (const exportSpecifier of exportSpecifiers) {
+                    statements = appendExportStatement(statements, exportSpecifier.name, name, /*location*/ exportSpecifier.name);
+                }
+            }
+            return statements;
         }
 
-        function getDeclarationName(node: DeclarationStatement) {
-            return node.name ? getSynthesizedClone(<Identifier>node.name) : getGeneratedNameForNode(node);
+        /**
+         * Appends the down-level representation of an export to a statement list, returning the
+         * statement list.
+         *
+         * If `statements` is `undefined`, a new array is allocated if statements are appended.
+         *
+         * @param statements The statement list to modify.
+         * @param exportName The name of the export.
+         * @param expression The expression to export.
+         * @param location The location to use for source maps and comments for the export.
+         * @param allowComments Whether to allow comments on the export.
+         */
+        function appendExportStatement(statements: Statement[] | undefined, exportName: Identifier, expression: Expression, location?: TextRange, allowComments?: boolean): Statement[] | undefined {
+            if (exportName.text === "default") {
+                const sourceFile = getOriginalNode(currentSourceFile, isSourceFile);
+                if (sourceFile && !sourceFile.symbol.exports["___esModule"]) {
+                    if (languageVersion === ScriptTarget.ES3) {
+                        statements = append(statements,
+                            createStatement(
+                                createExportAssignment(
+                                    createIdentifier("__esModule"),
+                                    createLiteral(true)
+                                )
+                            )
+                        );
+                    }
+                    else {
+                        statements = append(statements,
+                            createStatement(
+                                createCall(
+                                    createPropertyAccess(createIdentifier("Object"), "defineProperty"),
+                                    /*typeArguments*/ undefined,
+                                    [
+                                        createIdentifier("exports"),
+                                        createLiteral("__esModule"),
+                                        createObjectLiteral([
+                                            createPropertyAssignment("value", createLiteral(true))
+                                        ])
+                                    ]
+                                )
+                            )
+                        );
+                    }
+                }
+            }
+
+            statements = append(statements, createExportStatement(exportName, expression, location, allowComments));
+            return statements;
         }
 
+        /**
+         * Adds the down-level representation of `export=` to the statement list if one exists
+         * in the source file.
+         *
+         * @param statements The Statement list to modify.
+         * @param emitAsReturn A value indicating whether to emit the `export=` statement as a
+         *  return statement.
+         */
+        function addExportEqualsIfNeeded(statements: Statement[], emitAsReturn: boolean) {
+            if (currentModuleInfo.exportEquals) {
+                if (emitAsReturn) {
+                    const statement = createReturn(
+                        currentModuleInfo.exportEquals.expression,
+                        /*location*/ currentModuleInfo.exportEquals
+                    );
+
+                    setEmitFlags(statement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoComments);
+                    statements.push(statement);
+                }
+                else {
+                    const statement = createStatement(
+                        createAssignment(
+                            createPropertyAccess(
+                                createIdentifier("module"),
+                                "exports"
+                            ),
+                            currentModuleInfo.exportEquals.expression
+                        ),
+                        /*location*/ currentModuleInfo.exportEquals
+                    );
+
+                    setEmitFlags(statement, EmitFlags.NoComments);
+                    statements.push(statement);
+                }
+            }
+        }
+
+        /**
+         * Determines whether a node has an associated EndDeclarationMarker.
+         *
+         * @param node The node to test.
+         */
+        function hasAssociatedEndOfDeclarationMarker(node: Node) {
+            return (getEmitFlags(node) & EmitFlags.HasEndOfDeclarationMarker) !== 0;
+        }
+
+        /**
+         * Hook for node emit.
+         *
+         * @param node The node to emit.
+         * @param emitCallback A callback used to emit the node in the printer.
+         */
         function onEmitNode(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void {
             if (node.kind === SyntaxKind.SourceFile) {
-                bindingNameExportSpecifiersMap = bindingNameExportSpecifiersForFileMap[getOriginalNodeId(node)];
+                currentSourceFile = <SourceFile>node;
+                currentModuleInfo = moduleInfoMap[getOriginalNodeId(currentSourceFile)];
+                noSubstitution = createMap<boolean>();
+
                 previousOnEmitNode(emitContext, node, emitCallback);
-                bindingNameExportSpecifiersMap = undefined;
+
+                currentSourceFile = undefined;
+                currentModuleInfo = undefined;
+                noSubstitution = undefined;
             }
             else {
                 previousOnEmitNode(emitContext, node, emitCallback);
@@ -839,15 +997,26 @@ namespace ts {
          */
         function onSubstituteNode(emitContext: EmitContext, node: Node) {
             node = previousOnSubstituteNode(emitContext, node);
+            if (node.id && noSubstitution[node.id]) {
+                return node;
+            }
+
             if (emitContext === EmitContext.Expression) {
                 return substituteExpression(<Expression>node);
             }
             else if (isShorthandPropertyAssignment(node)) {
                 return substituteShorthandPropertyAssignment(node);
             }
+
             return node;
         }
 
+        /**
+         * Substitution for a ShorthandPropertyAssignment whose declaration name is an imported
+         * or exported symbol.
+         *
+         * @param node A ShorthandPropertyAssignment
+         */
         function substituteShorthandPropertyAssignment(node: ShorthandPropertyAssignment): ObjectLiteralElementLike {
             const name = node.name;
             const exportedOrImportedName = substituteExpressionIdentifier(name);
@@ -863,6 +1032,11 @@ namespace ts {
             return node;
         }
 
+        /**
+         * Substitution for an Expression that may contain an imported or exported symbol.
+         *
+         * @param node An Expression
+         */
         function substituteExpression(node: Expression) {
             switch (node.kind) {
                 case SyntaxKind.Identifier:
@@ -877,101 +1051,147 @@ namespace ts {
             return node;
         }
 
+        /**
+         * Substitution for an Identifier expression that may contain an imported or exported symbol.
+         *
+         * @param node An Identifier expression
+         */
         function substituteExpressionIdentifier(node: Identifier): Expression {
-            return trySubstituteExportedName(node)
-                || trySubstituteImportedName(node)
-                || node;
-        }
+            const emitFlags = getEmitFlags(node);
+            if ((emitFlags & EmitFlags.LocalName) === 0) {
+                const exportContainer = resolver.getReferencedExportContainer(node, (emitFlags & EmitFlags.ExportName) !== 0);
+                if (exportContainer && exportContainer.kind === SyntaxKind.SourceFile) {
+                    return createPropertyAccess(
+                        createIdentifier("exports"),
+                        getSynthesizedClone(node),
+                        /*location*/ node
+                    );
+                }
 
-        function substituteBinaryExpression(node: BinaryExpression): Expression {
-            const left = node.left;
-            // If the left-hand-side of the binaryExpression is an identifier and its is export through export Specifier
-            if (isIdentifier(left) && isAssignmentOperator(node.operatorToken.kind)) {
-                if (bindingNameExportSpecifiersMap && hasProperty(bindingNameExportSpecifiersMap, left.text)) {
-                    setEmitFlags(node, EmitFlags.NoSubstitution);
-                    let nestedExportAssignment: BinaryExpression;
-                    for (const specifier of bindingNameExportSpecifiersMap[left.text]) {
-                        nestedExportAssignment = nestedExportAssignment ?
-                            createExportAssignment(specifier.name, nestedExportAssignment) :
-                            createExportAssignment(specifier.name, node);
+                const importDeclaration = resolver.getReferencedImportDeclaration(node);
+                if (importDeclaration) {
+                    if (isImportClause(importDeclaration)) {
+                        return createPropertyAccess(
+                            getGeneratedNameForNode(importDeclaration.parent),
+                            createIdentifier("default"),
+                            /*location*/ node
+                        );
+                    }
+                    else if (isImportSpecifier(importDeclaration)) {
+                        const name = importDeclaration.propertyName || importDeclaration.name;
+                        return createPropertyAccess(
+                            getGeneratedNameForNode(importDeclaration.parent.parent.parent),
+                            getSynthesizedClone(name),
+                            /*location*/ node
+                        );
                     }
-                    return nestedExportAssignment;
                 }
             }
             return node;
         }
 
-        function substituteUnaryExpression(node: PrefixUnaryExpression | PostfixUnaryExpression): Expression {
-            // Because how the compiler only parse plusplus and minusminus to be either prefixUnaryExpression or postFixUnaryExpression depended on where they are
-            // We don't need to check that the operator has SyntaxKind.plusplus or SyntaxKind.minusminus
-            const operator = node.operator;
-            const operand = node.operand;
-            if (isIdentifier(operand) && bindingNameExportSpecifiersForFileMap) {
-                if (bindingNameExportSpecifiersMap && hasProperty(bindingNameExportSpecifiersMap, operand.text)) {
-                    setEmitFlags(node, EmitFlags.NoSubstitution);
-                    let transformedUnaryExpression: BinaryExpression;
-                    if (node.kind === SyntaxKind.PostfixUnaryExpression) {
-                        transformedUnaryExpression = createBinary(
-                            operand,
-                            createToken(operator === SyntaxKind.PlusPlusToken ? SyntaxKind.PlusEqualsToken : SyntaxKind.MinusEqualsToken),
-                            createLiteral(1),
-                            /*location*/ node
-                        );
-                        // We have to set no substitution flag here to prevent visit the binary expression and substitute it again as we will preform all necessary substitution in here
-                        setEmitFlags(transformedUnaryExpression, EmitFlags.NoSubstitution);
-                    }
-                    let nestedExportAssignment: BinaryExpression;
-                    for (const specifier of bindingNameExportSpecifiersMap[operand.text]) {
-                        nestedExportAssignment = nestedExportAssignment ?
-                            createExportAssignment(specifier.name, nestedExportAssignment) :
-                            createExportAssignment(specifier.name, transformedUnaryExpression || node);
+        /**
+         * Substitution for a BinaryExpression that may contain an imported or exported symbol.
+         *
+         * @param node A BinaryExpression
+         */
+        function substituteBinaryExpression(node: BinaryExpression): Expression {
+            // When we see an assignment expression whose left-hand side is an exported symbol,
+            // we should ensure all exports of that symbol are updated with the correct value.
+            //
+            // - We do not substitute generated identifiers for any reason.
+            // - We do not substitute identifiers tagged with the LocalName flag.
+            // - We do not substitute identifiers that were originally the name of an enum or
+            //   namespace due to how they are transformed in TypeScript.
+            // - We only substitute identifiers that are exported at the top level.
+            if (isAssignmentOperator(node.operatorToken.kind)
+                && isIdentifier(node.left)
+                && !isGeneratedIdentifier(node.left)
+                && !isLocalName(node.left)
+                && !isDeclarationNameOfEnumOrNamespace(node.left)) {
+                const exportedNames = getExportsOfName(node.left);
+                if (exportedNames) {
+                    // Since we will be reusing this node as part of the substitution, we
+                    // mark it to prevent triggering this rule again.
+                    noSubstitution[getNodeId(node)] = true;
+
+                    let expression: Expression = node;
+                    for (const exportName of exportedNames) {
+                        expression = createExportAssignment(exportName, expression);
+
+                        // Mark the transformed node to prevent possibly triggering this rule
+                        // again.
+                        noSubstitution[getNodeId(expression)] = true;
                     }
-                    return nestedExportAssignment;
+
+                    return expression;
                 }
             }
+
             return node;
         }
 
-        function trySubstituteExportedName(node: Identifier) {
-            const emitFlags = getEmitFlags(node);
-            if ((emitFlags & EmitFlags.LocalName) === 0) {
-                const container = resolver.getReferencedExportContainer(node, (emitFlags & EmitFlags.ExportName) !== 0);
-                if (container) {
-                    if (container.kind === SyntaxKind.SourceFile) {
-                        return createPropertyAccess(
-                            createIdentifier("exports"),
-                            getSynthesizedClone(node),
-                            /*location*/ node
-                        );
+        /**
+         * Substitution for a UnaryExpression that may contain an imported or exported symbol.
+         *
+         * @param node A UnaryExpression.
+         */
+        function substituteUnaryExpression(node: PrefixUnaryExpression | PostfixUnaryExpression): Expression {
+            // When we see a prefix or postfix increment expression whose operand is an exported
+            // symbol, we should ensure all exports of that symbol are updated with the correct
+            // value.
+            //
+            // - We do not substitute generated identifiers for any reason.
+            // - We do not substitute identifiers tagged with the LocalName flag.
+            // - We do not substitute identifiers that were originally the name of an enum or
+            //   namespace due to how they are transformed in TypeScript.
+            // - We only substitute identifiers that are exported at the top level.
+            if (isIdentifier(node.operand)
+                && !isGeneratedIdentifier(node.operand)
+                && !isLocalName(node.operand)
+                && !isDeclarationNameOfEnumOrNamespace(node.operand)) {
+                const exportedNames = getExportsOfName(node.operand);
+                if (exportedNames) {
+                    let expression = node.kind === SyntaxKind.PostfixUnaryExpression
+                        ? createBinary(
+                            node.operand,
+                            createToken(node.operator === SyntaxKind.PlusPlusToken ? SyntaxKind.PlusEqualsToken : SyntaxKind.MinusEqualsToken),
+                            createLiteral(1),
+                            /*location*/ node)
+                        : node;
+
+                    // Since we will be reusing this node as part of the substitution, we
+                    // mark it to prevent triggering this rule again.
+                    noSubstitution[getNodeId(expression)] = true;
+
+                    for (const exportName of exportedNames) {
+                        expression = createExportAssignment(exportName, expression);
+                        // Mark the transformed node to prevent triggering the assignment
+                        // expression substitution in `substituteBinaryExpression`.
+                        noSubstitution[getNodeId(expression)] = true;
                     }
+
+                    return expression;
                 }
             }
 
-            return undefined;
+            return node;
         }
 
-        function trySubstituteImportedName(node: Identifier): Expression {
-            if ((getEmitFlags(node) & EmitFlags.LocalName) === 0) {
-                const declaration = resolver.getReferencedImportDeclaration(node);
-                if (declaration) {
-                    if (isImportClause(declaration)) {
-                        return createPropertyAccess(
-                            getGeneratedNameForNode(declaration.parent),
-                            createIdentifier("default"),
-                            /*location*/ node
-                        );
-                    }
-                    else if (isImportSpecifier(declaration)) {
-                        const name = declaration.propertyName || declaration.name;
-                        return createPropertyAccess(
-                            getGeneratedNameForNode(declaration.parent.parent.parent),
-                            getSynthesizedClone(name),
-                            /*location*/ node
-                        );
-                    }
+        /**
+         * Gets the exports of a name.
+         *
+         * @param name The name.
+         */
+        function getExportsOfName(name: Identifier): Identifier[] | undefined {
+            if (!isGeneratedIdentifier(name)) {
+                const valueDeclaration = resolver.getReferencedImportDeclaration(name)
+                    || resolver.getReferencedValueDeclaration(name);
+                if (valueDeclaration) {
+                    return currentModuleInfo
+                        && currentModuleInfo.exportedBindings[getOriginalNodeId(valueDeclaration)];
                 }
             }
-            return undefined;
         }
 
         function getModuleMemberName(name: Identifier) {
@@ -992,11 +1212,11 @@ namespace ts {
             return createCall(createIdentifier("require"), /*typeArguments*/ undefined, args);
         }
 
-        function createExportStatement(name: Identifier, value: Expression, location?: TextRange) {
-            const statement = createStatement(createExportAssignment(name, value));
-            statement.startsOnNewLine = true;
-            if (location) {
-                setSourceMapRange(statement, location);
+        function createExportStatement(name: Identifier, value: Expression, location?: TextRange, allowComments?: boolean) {
+            const statement = createStatement(createExportAssignment(name, value), location);
+            startOnNewLine(statement);
+            if (!allowComments) {
+                setEmitFlags(statement, EmitFlags.NoComments);
             }
 
             return statement;
@@ -1041,7 +1261,7 @@ namespace ts {
                 }
             }
 
-            for (const importNode of externalImports) {
+            for (const importNode of currentModuleInfo.externalImports) {
                 // Find the name of the external module
                 const externalModuleName = getExternalModuleNameLiteral(importNode, currentSourceFile, host, resolver, compilerOptions);
 
diff --git a/src/compiler/transformers/module/system.ts b/src/compiler/transformers/module/system.ts
index acd25a41a090f..8bea1e3d28a3c 100644
--- a/src/compiler/transformers/module/system.ts
+++ b/src/compiler/transformers/module/system.ts
@@ -90,7 +90,7 @@ namespace ts {
             Debug.assert(!exportFunctionForFile);
 
             // Collect information about the external module and dependency groups.
-            ({ externalImports, exportSpecifiers, exportEquals, hasExportStarsToExportValues } = collectExternalModuleInfo(node));
+            ({ externalImports, exportSpecifiers, exportEquals, hasExportStarsToExportValues } = collectExternalModuleInfo(node, resolver));
 
             // Make sure that the name of the 'exports' function does not conflict with
             // existing identifiers.
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index fdb3f7b208d9a..0e1821159bec0 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -241,6 +241,18 @@ namespace ts {
             }
         }
 
+        function modifierVisitor(node: Node): VisitResult<Node> {
+            if (modifierToFlag(node.kind) & ModifierFlags.TypeScriptModifier) {
+                return undefined;
+            }
+            else if (currentNamespace && node.kind === SyntaxKind.ExportKeyword) {
+                return undefined;
+            }
+
+            return node;
+        }
+
+
         /**
          * Branching visitor, visits a TypeScript syntax node.
          *
@@ -535,7 +547,6 @@ namespace ts {
             const staticProperties = getInitializedProperties(node, /*isStatic*/ true);
             const hasExtendsClause = getClassExtendsHeritageClauseElement(node) !== undefined;
             const isDecoratedClass = shouldEmitDecorateCallForClass(node);
-            let classAlias: Identifier;
 
             // emit name if
             // - node has a name
@@ -546,33 +557,11 @@ namespace ts {
                 name = getGeneratedNameForNode(node);
             }
 
-            const statements: Statement[] = [];
-            if (!isDecoratedClass) {
-                //  ${modifiers} class ${name} ${heritageClauses} {
-                //      ${members}
-                //  }
-                const classDeclaration = createClassDeclaration(
-                    /*decorators*/ undefined,
-                    visitNodes(node.modifiers, visitor, isModifier),
-                    name,
-                    /*typeParameters*/ undefined,
-                    visitNodes(node.heritageClauses, visitor, isHeritageClause),
-                    transformClassMembers(node, hasExtendsClause),
-                    /*location*/ node
-                );
-                setOriginalNode(classDeclaration, node);
+            const classStatement = isDecoratedClass
+                ? createClassDeclarationHeadWithDecorators(node, name, hasExtendsClause)
+                : createClassDeclarationHeadWithoutDecorators(node, name, hasExtendsClause, staticProperties.length > 0);
 
-                // To better align with the old emitter, we should not emit a trailing source map
-                // entry if the class has static properties.
-                if (staticProperties.length > 0) {
-                    setEmitFlags(classDeclaration, EmitFlags.NoTrailingSourceMap | getEmitFlags(classDeclaration));
-                }
-
-                statements.push(classDeclaration);
-            }
-            else {
-                classAlias = addClassDeclarationHeadWithDecorators(statements, node, name, hasExtendsClause);
-            }
+            const statements: Statement[] = [classStatement];
 
             // Emit static property assignment. Because classDeclaration is lexically evaluated,
             // it is safe to emit static property assignment after classDeclaration
@@ -580,13 +569,13 @@ namespace ts {
             //      HasLexicalDeclaration (N) : Determines if the argument identifier has a binding in this environment record that was created using
             //                                  a lexical declaration such as a LexicalDeclaration or a ClassDeclaration.
             if (staticProperties.length) {
-                addInitializedPropertyStatements(statements, node, staticProperties, getLocalName(node, /*noSourceMaps*/ true));
+                addInitializedPropertyStatements(statements, node, staticProperties, getLocalName(node));
             }
 
             // Write any decorators of the node.
             addClassElementDecorationStatements(statements, node, /*isStatic*/ false);
             addClassElementDecorationStatements(statements, node, /*isStatic*/ true);
-            addConstructorDecorationStatement(statements, node, classAlias);
+            addConstructorDecorationStatement(statements, node);
 
             // If the class is exported as part of a TypeScript namespace, emit the namespace export.
             // Otherwise, if the class was exported at the top level and was decorated, emit an export
@@ -596,18 +585,54 @@ namespace ts {
             }
             else if (isDecoratedClass) {
                 if (isDefaultExternalModuleExport(node)) {
-                    statements.push(createExportAssignment(
-                        /*decorators*/ undefined,
-                        /*modifiers*/ undefined,
-                        /*isExportEquals*/ false,
-                        getLocalName(node)));
+                    statements.push(createExportDefault(getLocalName(node, /*allowComments*/ false, /*allowSourceMaps*/ true)));
                 }
                 else if (isNamedExternalModuleExport(node)) {
-                    statements.push(createExternalModuleExport(name));
+                    statements.push(createExternalModuleExport(getLocalName(node, /*allowComments*/ false, /*allowSourceMaps*/ true)));
                 }
             }
 
-            return statements;
+            if (statements.length > 1) {
+                // Add a DeclarationMarker as a marker for the end of the declaration
+                statements.push(createEndOfDeclarationMarker(node));
+                setEmitFlags(classStatement, getEmitFlags(classStatement) | EmitFlags.HasEndOfDeclarationMarker);
+            }
+
+            return singleOrMany(statements);
+        }
+
+        /**
+         * Transforms a non-decorated class declaration and appends the resulting statements.
+         *
+         * @param node A ClassDeclaration node.
+         * @param name The name of the class.
+         * @param hasExtendsClause A value indicating whether the class has an extends clause.
+         * @param hasStaticProperties A value indicating whether the class has static properties.
+         */
+        function createClassDeclarationHeadWithoutDecorators(node: ClassDeclaration, name: Identifier, hasExtendsClause: boolean, hasStaticProperties: boolean) {
+            //  ${modifiers} class ${name} ${heritageClauses} {
+            //      ${members}
+            //  }
+            const classDeclaration = createClassDeclaration(
+                /*decorators*/ undefined,
+                visitNodes(node.modifiers, modifierVisitor, isModifier),
+                name,
+                /*typeParameters*/ undefined,
+                visitNodes(node.heritageClauses, visitor, isHeritageClause),
+                transformClassMembers(node, hasExtendsClause),
+                node);
+
+            let emitFlags = getEmitFlags(node);
+
+            // To better align with the old emitter, we should not emit a trailing source map
+            // entry if the class has static properties.
+            if (hasStaticProperties) {
+                emitFlags |= EmitFlags.NoTrailingSourceMap;
+            }
+
+            setOriginalNode(classDeclaration, node);
+            setEmitFlags(classDeclaration, emitFlags);
+            return classDeclaration;
         }
 
         /**
@@ -619,7 +644,7 @@ namespace ts {
          * @param name The name of the class.
          * @param hasExtendsClause A value indicating whether the class has an extends clause.
          */
-        function addClassDeclarationHeadWithDecorators(statements: Statement[], node: ClassDeclaration, name: Identifier, hasExtendsClause: boolean) {
+        function createClassDeclarationHeadWithDecorators(node: ClassDeclaration, name: Identifier, hasExtendsClause: boolean) {
             // When we emit an ES6 class that has a class decorator, we must tailor the
             // emit to certain specific cases.
             //
@@ -654,20 +679,20 @@ namespace ts {
             //  ---------------------------------------------------------------------
             //  TypeScript                      | Javascript
             //  ---------------------------------------------------------------------
-            //  @dec                            | let C_1 = class C {
+            //  @dec                            | let C = C_1 = class C {
             //  class C {                       |   static x() { return C_1.y; }
             //    static x() { return C.y; }    | }
-            //    static y = 1;                 | let C = C_1;
-            //  }                               | C.y = 1;
-            //                                  | C = C_1 = __decorate([dec], C);
+            //    static y = 1;                 | C.y = 1;
+            //  }                               | C = C_1 = __decorate([dec], C);
+            //                                  | var C_1;
             //  ---------------------------------------------------------------------
-            //  @dec                            | let C_1 = class C {
+            //  @dec                            | let C = class C {
             //  export class C {                |   static x() { return C_1.y; }
             //    static x() { return C.y; }    | }
-            //    static y = 1;                 | let C = C_1;
-            //  }                               | C.y = 1;
-            //                                  | C = C_1 = __decorate([dec], C);
+            //    static y = 1;                 | C.y = 1;
+            //  }                               | C = C_1 = __decorate([dec], C);
             //                                  | export { C };
+            //                                  | var C_1;
             //  ---------------------------------------------------------------------
             //
             // If a class declaration is the default export of a module, we instead emit
@@ -696,92 +721,34 @@ namespace ts {
             //  ---------------------------------------------------------------------
             //  TypeScript                      | Javascript
             //  ---------------------------------------------------------------------
-            //  @dec                            | let C_1 = class C {
+            //  @dec                            | let C = class C {
             //  export default class C {        |   static x() { return C_1.y; }
             //    static x() { return C.y; }    | }
-            //    static y = 1;                 | let C = C_1;
-            //  }                               | C.y = 1;
-            //                                  | C = C_1 = __decorate([dec], C);
+            //    static y = 1;                 | C.y = 1;
+            //  }                               | C = C_1 = __decorate([dec], C);
             //                                  | export default C;
+            //                                  | var C_1;
             //  ---------------------------------------------------------------------
             //
 
             const location = moveRangePastDecorators(node);
+            const classAlias = getClassAliasIfNeeded(node);
+            const declName = getLocalName(node, /*allowComments*/ false, /*allowSourceMaps*/ true);
 
             //  ... = class ${name} ${heritageClauses} {
             //      ${members}
             //  }
-            const classExpression: Expression = setOriginalNode(
-                createClassExpression(
-                    /*modifiers*/ undefined,
-                    name,
-                    /*typeParameters*/ undefined,
-                    visitNodes(node.heritageClauses, visitor, isHeritageClause),
-                    transformClassMembers(node, hasExtendsClause),
-                    /*location*/ location
-                ),
-                node
-            );
-
-            if (!name) {
-                name = getGeneratedNameForNode(node);
-            }
-
-            // Record an alias to avoid class double-binding.
-            let classAlias: Identifier;
-            if (resolver.getNodeCheckFlags(node) & NodeCheckFlags.ClassWithConstructorReference) {
-                enableSubstitutionForClassAliases();
-                classAlias = createUniqueName(node.name && !isGeneratedIdentifier(node.name) ? node.name.text : "default");
-                classAliases[getOriginalNodeId(node)] = classAlias;
-            }
-
-            const declaredName = getDeclarationName(node, /*allowComments*/ true);
+            const heritageClauses = visitNodes(node.heritageClauses, visitor, isHeritageClause);
+            const members = transformClassMembers(node, hasExtendsClause);
+            const classExpression = createClassExpression(/*modifiers*/ undefined, name, /*typeParameters*/ undefined, heritageClauses, members, location);
+            setOriginalNode(classExpression, node);
 
             //  let ${name} = ${classExpression} where name is either declaredName if the class doesn't contain self-reference
             //                                         or decoratedClassAlias if the class contain self-reference.
-            const transformedClassExpression = createVariableStatement(
-                /*modifiers*/ undefined,
-                createLetDeclarationList([
-                    createVariableDeclaration(
-                        classAlias || declaredName,
-                        /*type*/ undefined,
-                        classExpression
-                    )
-                ]),
-                /*location*/ location
-            );
-            setCommentRange(transformedClassExpression, node);
-            statements.push(
-                setOriginalNode(
-                    /*node*/ transformedClassExpression,
-                    /*original*/ node
-                )
-            );
-
-            if (classAlias) {
-                // We emit the class alias as a `let` declaration here so that it has the same
-                // TDZ as the class.
-
-                // let ${declaredName} = ${decoratedClassAlias}
-                statements.push(
-                    setOriginalNode(
-                        createVariableStatement(
-                            /*modifiers*/ undefined,
-                            createLetDeclarationList([
-                                createVariableDeclaration(
-                                    declaredName,
-                                    /*type*/ undefined,
-                                    classAlias
-                                )
-                            ]),
-                            /*location*/ location
-                        ),
-                        /*original*/ node
-                    )
-                );
-            }
-
-            return classAlias;
+            const statement = createLetStatement(declName, classAlias ? createAssignment(classAlias, classExpression) : classExpression, location);
+            setOriginalNode(statement, node);
+            setCommentRange(statement, node);
+            return statement;
         }
 
         /**
@@ -992,7 +959,7 @@ namespace ts {
                         statements,
                         /*location*/ constructor ? constructor.body.statements : node.members
                     ),
-                    /*location*/ constructor ? constructor.body : undefined
+                    /*location*/ constructor ? constructor.body : /*location*/ undefined
                 ),
                 true
             );
@@ -1472,8 +1439,8 @@ namespace ts {
          *
          * @param node The class node.
          */
-        function addConstructorDecorationStatement(statements: Statement[], node: ClassDeclaration, decoratedClassAlias: Identifier) {
-            const expression = generateConstructorDecorationExpression(node, decoratedClassAlias);
+        function addConstructorDecorationStatement(statements: Statement[], node: ClassDeclaration) {
+            const expression = generateConstructorDecorationExpression(node);
             if (expression) {
                 statements.push(setOriginalNode(createStatement(expression), node));
             }
@@ -1484,61 +1451,20 @@ namespace ts {
          *
          * @param node The class node.
          */
-        function generateConstructorDecorationExpression(node: ClassExpression | ClassDeclaration, decoratedClassAlias: Identifier) {
+        function generateConstructorDecorationExpression(node: ClassExpression | ClassDeclaration) {
             const allDecorators = getAllDecoratorsOfConstructor(node);
             const decoratorExpressions = transformAllDecoratorsOfDeclaration(node, allDecorators);
             if (!decoratorExpressions) {
                 return undefined;
             }
 
-            // Emit the call to __decorate. Given the class:
-            //
-            //   @dec
-            //   class C {
-            //   }
-            //
-            // The emit for the class is:
-            //
-            //   C = C_1 = __decorate([dec], C);
-            //
-            if (decoratedClassAlias) {
-                const expression = createAssignment(
-                    decoratedClassAlias,
-                    createDecorateHelper(
-                        currentExternalHelpersModuleName,
-                        decoratorExpressions,
-                        getDeclarationName(node)
-                    )
-                );
-
-                const result = createAssignment(getDeclarationName(node), expression, moveRangePastDecorators(node));
-                setEmitFlags(result, EmitFlags.NoComments);
-                return result;
-            }
-            // Emit the call to __decorate. Given the class:
-            //
-            //   @dec
-            //   export declare class C {
-            //   }
-            //
-            // The emit for the class is:
-            //
-            //   C = __decorate([dec], C);
-            //
-            else {
-                const result = createAssignment(
-                    getDeclarationName(node),
-                    createDecorateHelper(
-                        currentExternalHelpersModuleName,
-                        decoratorExpressions,
-                        getDeclarationName(node)
-                    ),
-                    moveRangePastDecorators(node)
-                );
-
-                setEmitFlags(result, EmitFlags.NoComments);
-                return result;
-            }
+            const classAlias = classAliases && classAliases[getOriginalNodeId(node)];
+            const localName = getLocalName(node, /*allowComments*/ false, /*allowSourceMaps*/ true);
+            const decorate = createDecorateHelper(currentExternalHelpersModuleName, decoratorExpressions, localName);
+            const expression = createAssignment(localName, classAlias ? createAssignment(classAlias, decorate) : decorate);
+            setEmitFlags(expression, EmitFlags.NoComments);
+            setSourceMapRange(expression, moveRangePastDecorators(node));
+            return expression;
         }
 
         /**
@@ -2134,7 +2060,7 @@ namespace ts {
 
             const method = createMethod(
                 /*decorators*/ undefined,
-                visitNodes(node.modifiers, visitor, isModifier),
+                visitNodes(node.modifiers, modifierVisitor, isModifier),
                 node.asteriskToken,
                 visitPropertyNameOfClassElement(node),
                 /*typeParameters*/ undefined,
@@ -2179,7 +2105,7 @@ namespace ts {
 
             const accessor = createGetAccessor(
                 /*decorators*/ undefined,
-                visitNodes(node.modifiers, visitor, isModifier),
+                visitNodes(node.modifiers, modifierVisitor, isModifier),
                 visitPropertyNameOfClassElement(node),
                 visitNodes(node.parameters, visitor, isParameter),
                 /*type*/ undefined,
@@ -2212,7 +2138,7 @@ namespace ts {
 
             const accessor = createSetAccessor(
                 /*decorators*/ undefined,
-                visitNodes(node.modifiers, visitor, isModifier),
+                visitNodes(node.modifiers, modifierVisitor, isModifier),
                 visitPropertyNameOfClassElement(node),
                 visitNodes(node.parameters, visitor, isParameter),
                 node.body ? visitEachChild(node.body, visitor, context) : createBlock([]),
@@ -2245,7 +2171,7 @@ namespace ts {
 
             const func = createFunctionDeclaration(
                 /*decorators*/ undefined,
-                visitNodes(node.modifiers, visitor, isModifier),
+                visitNodes(node.modifiers, modifierVisitor, isModifier),
                 node.asteriskToken,
                 node.name,
                 /*typeParameters*/ undefined,
@@ -2279,7 +2205,7 @@ namespace ts {
             }
 
             const func = createFunctionExpression(
-                visitNodes(node.modifiers, visitor, isModifier),
+                visitNodes(node.modifiers, modifierVisitor, isModifier),
                 node.asteriskToken,
                 node.name,
                 /*typeParameters*/ undefined,
@@ -2301,7 +2227,7 @@ namespace ts {
          */
         function visitArrowFunction(node: ArrowFunction) {
             const func = createArrowFunction(
-                visitNodes(node.modifiers, visitor, isModifier),
+                visitNodes(node.modifiers, modifierVisitor, isModifier),
                 /*typeParameters*/ undefined,
                 visitNodes(node.parameters, visitor, isParameter),
                 /*type*/ undefined,
@@ -2538,10 +2464,7 @@ namespace ts {
             // If needed, we should emit a variable declaration for the enum. If we emit
             // a leading variable declaration, we should not emit leading comments for the
             // enum body.
-            recordEmittedDeclarationInScope(node);
-            if (isFirstEmittedDeclarationInScope(node)) {
-                addVarForEnumOrModuleDeclaration(statements, node);
-
+            if (addVarForEnumOrModuleDeclaration(statements, node)) {
                 // We should still emit the comments if we are emitting a system module.
                 if (moduleKind !== ModuleKind.System || currentScope !== currentSourceFile) {
                     emitFlags |= EmitFlags.NoLeadingComments;
@@ -2555,7 +2478,9 @@ namespace ts {
             const containerName = getNamespaceContainerName(node);
 
             // `exportName` is the expression used within this node's container for any exported references.
-            const exportName = getExportName(node);
+            const exportName = hasModifier(node, ModifierFlags.Export)
+                ? getExternalModuleOrNamespaceExportName(currentNamespaceContainerName, node, /*allowComments*/ false, /*allowSourceMaps*/ true)
+                : getLocalName(node, /*allowComments*/ false, /*allowSourceMaps*/ true);
 
             //  x || (x = {})
             //  exports.x || (exports.x = {})
@@ -2568,9 +2493,9 @@ namespace ts {
                     )
                 );
 
-            if (hasModifier(node, ModifierFlags.Export) && !isES6ExportedDeclaration(node)) {
+            if (hasNamespaceQualifiedExportName(node)) {
                 // `localName` is the expression used within this node's containing scope for any local references.
-                const localName = getLocalName(node);
+                const localName = getLocalName(node, /*allowComments*/ false, /*allowSourceMaps*/ true);
 
                 //  x = (exports.x || (exports.x = {}))
                 moduleArg = createAssignment(localName, moduleArg);
@@ -2600,6 +2525,10 @@ namespace ts {
             setOriginalNode(enumStatement, node);
             setEmitFlags(enumStatement, emitFlags);
             statements.push(enumStatement);
+
+            // Add a DeclarationMarker for the enum to preserve trailing comments and mark
+            // the end of the declaration.
+            statements.push(createEndOfDeclarationMarker(node));
             return statements;
         }
 
@@ -2684,9 +2613,15 @@ namespace ts {
             return isInstantiatedModule(node, compilerOptions.preserveConstEnums || compilerOptions.isolatedModules);
         }
 
-        function isES6ExportedDeclaration(node: Node) {
-            return isExternalModuleExport(node)
-                && moduleKind === ModuleKind.ES2015;
+        /**
+         * Determines whether an exported declaration will have a qualified export name (e.g. `f.x`
+         * or `exports.x`).
+         */
+        function hasNamespaceQualifiedExportName(node: Node) {
+            return isNamespaceExport(node)
+                || (isExternalModuleExport(node)
+                    && moduleKind !== ModuleKind.ES2015
+                    && moduleKind !== ModuleKind.System);
         }
 
         /**
@@ -2730,47 +2665,55 @@ namespace ts {
         function addVarForEnumOrModuleDeclaration(statements: Statement[], node: ModuleDeclaration | EnumDeclaration) {
             // Emit a variable statement for the module.
             const statement = createVariableStatement(
-                isES6ExportedDeclaration(node)
-                    ? visitNodes(node.modifiers, visitor, isModifier)
-                    : undefined,
+                visitNodes(node.modifiers, modifierVisitor, isModifier),
                 [
                     createVariableDeclaration(
-                        getDeclarationName(node, /*allowComments*/ false, /*allowSourceMaps*/ true)
+                        getLocalName(node, /*allowComments*/ false, /*allowSourceMaps*/ true)
                     )
                 ]
             );
 
             setOriginalNode(statement, node);
 
-            // Adjust the source map emit to match the old emitter.
-            if (node.kind === SyntaxKind.EnumDeclaration) {
-                setSourceMapRange(statement.declarationList, node);
+            recordEmittedDeclarationInScope(node);
+            if (isFirstEmittedDeclarationInScope(node)) {
+                // Adjust the source map emit to match the old emitter.
+                if (node.kind === SyntaxKind.EnumDeclaration) {
+                    setSourceMapRange(statement.declarationList, node);
+                }
+                else {
+                    setSourceMapRange(statement, node);
+                }
+
+                // Trailing comments for module declaration should be emitted after the function closure
+                // instead of the variable statement:
+                //
+                //     /** Module comment*/
+                //     module m1 {
+                //         function foo4Export() {
+                //         }
+                //     } // trailing comment module
+                //
+                // Should emit:
+                //
+                //     /** Module comment*/
+                //     var m1;
+                //     (function (m1) {
+                //         function foo4Export() {
+                //         }
+                //     })(m1 || (m1 = {})); // trailing comment module
+                //
+                setCommentRange(statement, node);
+                setEmitFlags(statement, EmitFlags.NoTrailingComments | EmitFlags.HasEndOfDeclarationMarker);
+                statements.push(statement);
+                return true;
             }
             else {
-                setSourceMapRange(statement, node);
+                const notEmittedStatement = createNotEmittedStatement(statement);
+                setEmitFlags(notEmittedStatement, EmitFlags.NoComments);
+                statements.push(notEmittedStatement);
+                return false;
             }
-
-            // Trailing comments for module declaration should be emitted after the function closure
-            // instead of the variable statement:
-            //
-            //     /** Module comment*/
-            //     module m1 {
-            //         function foo4Export() {
-            //         }
-            //     } // trailing comment module
-            //
-            // Should emit:
-            //
-            //     /** Module comment*/
-            //     var m1;
-            //     (function (m1) {
-            //         function foo4Export() {
-            //         }
-            //     })(m1 || (m1 = {})); // trailing comment module
-            //
-            setCommentRange(statement, node);
-            setEmitFlags(statement, EmitFlags.NoTrailingComments);
-            statements.push(statement);
         }
 
         /**
@@ -2797,9 +2740,7 @@ namespace ts {
             // If needed, we should emit a variable declaration for the module. If we emit
             // a leading variable declaration, we should not emit leading comments for the
             // module body.
-            recordEmittedDeclarationInScope(node);
-            if (isFirstEmittedDeclarationInScope(node)) {
-                addVarForEnumOrModuleDeclaration(statements, node);
+            if (addVarForEnumOrModuleDeclaration(statements, node)) {
                 // We should still emit the comments if we are emitting a system module.
                 if (moduleKind !== ModuleKind.System || currentScope !== currentSourceFile) {
                     emitFlags |= EmitFlags.NoLeadingComments;
@@ -2813,7 +2754,9 @@ namespace ts {
             const containerName = getNamespaceContainerName(node);
 
             // `exportName` is the expression used within this node's container for any exported references.
-            const exportName = getExportName(node);
+            const exportName = hasModifier(node, ModifierFlags.Export)
+                ? getExternalModuleOrNamespaceExportName(currentNamespaceContainerName, node, /*allowComments*/ false, /*allowSourceMaps*/ true)
+                : getLocalName(node, /*allowComments*/ false, /*allowSourceMaps*/ true);
 
             //  x || (x = {})
             //  exports.x || (exports.x = {})
@@ -2826,9 +2769,9 @@ namespace ts {
                     )
                 );
 
-            if (hasModifier(node, ModifierFlags.Export) && !isES6ExportedDeclaration(node)) {
+            if (hasNamespaceQualifiedExportName(node)) {
                 // `localName` is the expression used within this node's containing scope for any local references.
-                const localName = getLocalName(node);
+                const localName = getLocalName(node, /*allowComments*/ false, /*allowSourceMaps*/ true);
 
                 //  x = (exports.x || (exports.x = {}))
                 moduleArg = createAssignment(localName, moduleArg);
@@ -2857,6 +2800,10 @@ namespace ts {
             setOriginalNode(moduleStatement, node);
             setEmitFlags(moduleStatement, emitFlags);
             statements.push(moduleStatement);
+
+            // Add a DeclarationMarker for the namespace to preserve trailing comments and mark
+            // the end of the declaration.
+            statements.push(createEndOfDeclarationMarker(node));
             return statements;
         }
 
@@ -3112,7 +3059,7 @@ namespace ts {
                 //  var ${name} = ${moduleReference};
                 return setOriginalNode(
                     createVariableStatement(
-                        visitNodes(node.modifiers, visitor, isModifier),
+                        visitNodes(node.modifiers, modifierVisitor, isModifier),
                         createVariableDeclarationList([
                             createVariableDeclaration(
                                 node.name,
@@ -3185,8 +3132,8 @@ namespace ts {
 
         function addExportMemberAssignment(statements: Statement[], node: ClassDeclaration | FunctionDeclaration) {
             const expression = createAssignment(
-                getExportName(node),
-                getLocalName(node, /*noSourceMaps*/ true)
+                getExternalModuleOrNamespaceExportName(currentNamespaceContainerName, node, /*allowComments*/ false, /*allowSourceMaps*/ true),
+                getLocalName(node)
             );
             setSourceMapRange(expression, createRange(node.name.pos, node.end));
 
@@ -3198,40 +3145,15 @@ namespace ts {
         function createNamespaceExport(exportName: Identifier, exportValue: Expression, location?: TextRange) {
             return createStatement(
                 createAssignment(
-                    getNamespaceMemberName(exportName, /*allowComments*/ false, /*allowSourceMaps*/ true),
+                    getNamespaceMemberName(currentNamespaceContainerName, exportName, /*allowComments*/ false, /*allowSourceMaps*/ true),
                     exportValue
                 ),
                 location
             );
         }
 
-        function createExternalModuleExport(exportName: Identifier) {
-            return createExportDeclaration(
-                /*decorators*/ undefined,
-                /*modifiers*/ undefined,
-                createNamedExports([
-                    createExportSpecifier(exportName)
-                ])
-            );
-        }
-
-        function getNamespaceMemberName(name: Identifier, allowComments?: boolean, allowSourceMaps?: boolean): Expression {
-            const qualifiedName = createPropertyAccess(currentNamespaceContainerName, getSynthesizedClone(name), /*location*/ name);
-            let emitFlags: EmitFlags;
-            if (!allowComments) {
-                emitFlags |= EmitFlags.NoComments;
-            }
-            if (!allowSourceMaps) {
-                emitFlags |= EmitFlags.NoSourceMap;
-            }
-            if (emitFlags) {
-                setEmitFlags(qualifiedName, emitFlags);
-            }
-            return qualifiedName;
-        }
-
         function getNamespaceMemberNameWithSourceMapsAndWithoutComments(name: Identifier) {
-            return getNamespaceMemberName(name, /*allowComments*/ false, /*allowSourceMaps*/ true);
+            return getNamespaceMemberName(currentNamespaceContainerName, name, /*allowComments*/ false, /*allowSourceMaps*/ true);
         }
 
         /**
@@ -3252,65 +3174,17 @@ namespace ts {
         }
 
         /**
-         * Gets the local name for a declaration for use in expressions.
-         *
-         * A local name will *never* be prefixed with an module or namespace export modifier like
-         * "exports.".
-         *
-         * @param node The declaration.
-         * @param noSourceMaps A value indicating whether source maps may not be emitted for the name.
-         * @param allowComments A value indicating whether comments may be emitted for the name.
-         */
-        function getLocalName(node: FunctionDeclaration | ClassDeclaration | ClassExpression | ModuleDeclaration | EnumDeclaration, noSourceMaps?: boolean, allowComments?: boolean) {
-            return getDeclarationName(node, allowComments, !noSourceMaps, EmitFlags.LocalName);
-        }
-
-        /**
-         * Gets the export name for a declaration for use in expressions.
-         *
-         * An export name will *always* be prefixed with an module or namespace export modifier
-         * like "exports." if one is required.
-         *
-         * @param node The declaration.
-         * @param noSourceMaps A value indicating whether source maps may not be emitted for the name.
-         * @param allowComments A value indicating whether comments may be emitted for the name.
-         */
-        function getExportName(node: FunctionDeclaration | ClassDeclaration | ClassExpression | ModuleDeclaration | EnumDeclaration, noSourceMaps?: boolean, allowComments?: boolean) {
-            if (isNamespaceExport(node)) {
-                return getNamespaceMemberName(getDeclarationName(node), allowComments, !noSourceMaps);
-            }
-
-            return getDeclarationName(node, allowComments, !noSourceMaps, EmitFlags.ExportName);
-        }
-
-        /**
-         * Gets the name for a declaration for use in declarations.
-         *
-         * @param node The declaration.
-         * @param allowComments A value indicating whether comments may be emitted for the name.
-         * @param allowSourceMaps A value indicating whether source maps may be emitted for the name.
-         * @param emitFlags Additional NodeEmitFlags to specify for the name.
+         * Gets a local alias for a class declaration if it is a decorated class with an internal
+         * reference to the static side of the class. This is necessary to avoid issues with
+         * double-binding semantics for the class name.
          */
-        function getDeclarationName(node: FunctionDeclaration | ClassDeclaration | ClassExpression | ModuleDeclaration | EnumDeclaration, allowComments?: boolean, allowSourceMaps?: boolean, emitFlags?: EmitFlags) {
-            if (node.name) {
-                const name = getMutableClone(<Identifier>node.name);
-                emitFlags |= getEmitFlags(node.name);
-                if (!allowSourceMaps) {
-                    emitFlags |= EmitFlags.NoSourceMap;
-                }
-
-                if (!allowComments) {
-                    emitFlags |= EmitFlags.NoComments;
-                }
-
-                if (emitFlags) {
-                    setEmitFlags(name, emitFlags);
-                }
-
-                return name;
-            }
-            else {
-                return getGeneratedNameForNode(node);
+        function getClassAliasIfNeeded(node: ClassDeclaration) {
+            if (resolver.getNodeCheckFlags(node) & NodeCheckFlags.ClassWithConstructorReference) {
+                enableSubstitutionForClassAliases();
+                const classAlias = createUniqueName(node.name && !isGeneratedIdentifier(node.name) ? node.name.text : "default");
+                classAliases[getOriginalNodeId(node)] = classAlias;
+                hoistVariableDeclaration(classAlias);
+                return classAlias;
             }
         }
 
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index d031188571db6..93fd9afb79c0e 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -362,6 +362,7 @@ namespace ts {
         // Transformation nodes
         NotEmittedStatement,
         PartiallyEmittedExpression,
+        EndOfDeclarationMarker,
 
         // Enum value count
         Count,
@@ -457,7 +458,8 @@ namespace ts {
         ParameterPropertyModifier = AccessibilityModifier | Readonly,
         NonPublicAccessibilityModifier = Private | Protected,
 
-        TypeScriptModifier = Ambient | Public | Private | Protected | Readonly | Abstract | Const
+        TypeScriptModifier = Ambient | Public | Private | Protected | Readonly | Abstract | Const,
+        ExportDefault = Export | Default,
     }
 
     export const enum JsxFlags {
@@ -1426,6 +1428,14 @@ namespace ts {
         kind: SyntaxKind.NotEmittedStatement;
     }
 
+    /**
+     * Marks the end of transformed declaration to properly emit exports.
+     */
+    /* @internal */
+    export interface EndOfDeclarationMarker extends Statement {
+        kind: SyntaxKind.EndOfDeclarationMarker;
+    }
+
     export interface EmptyStatement extends Statement {
         kind: SyntaxKind.EmptyStatement;
     }
@@ -3367,9 +3377,9 @@ namespace ts {
         ContainsES2016 = 1 << 7,
         ES2015 = 1 << 8,
         ContainsES2015 = 1 << 9,
-        DestructuringAssignment = 1 << 10,
-        Generator = 1 << 11,
-        ContainsGenerator = 1 << 12,
+        Generator = 1 << 10,
+        ContainsGenerator = 1 << 11,
+        DestructuringAssignment = 1 << 12,
 
         // Markers
         // - Flags used to indicate that a subtree contains a specific transformation.
@@ -3454,11 +3464,14 @@ namespace ts {
         NoNestedComments = 1 << 16,
         ExportName = 1 << 17,                    // Ensure an export prefix is added for an identifier that points to an exported declaration with a local name (see SymbolFlags.ExportHasLocal).
         LocalName = 1 << 18,                     // Ensure an export prefix is not added for an identifier that points to an exported declaration.
+        ExportBindingName = LocalName | ExportName,
         Indented = 1 << 19,                      // Adds an explicit extra indentation level for class and function bodies when printing (used to match old emitter).
         NoIndentation = 1 << 20,                 // Do not indent the node.
         AsyncFunctionBody = 1 << 21,
         ReuseTempVariableScope = 1 << 22,        // Reuse the existing temp variable scope during emit.
         CustomPrologue = 1 << 23,                // Treat the statement as if it were a prologue directive (NOTE: Prologue directives are *not* transformed).
+        NoHoisting = 1 << 24,                    // Do not hoist this declaration in --module system
+        HasEndOfDeclarationMarker = 1 << 25,     // Declaration has an associated NotEmittedStatement to mark the end of the declaration
     }
 
     /* @internal */
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index c4e6712015cb9..ac0dd1af72062 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -1953,14 +1953,16 @@ namespace ts {
             || positionIsSynthesized(node.end);
     }
 
-    export function getOriginalNode(node: Node): Node {
+    export function getOriginalNode(node: Node): Node;
+    export function getOriginalNode<T extends Node>(node: Node, nodeTest: (node: Node) => node is T): T;
+    export function getOriginalNode(node: Node, nodeTest?: (node: Node) => boolean): Node {
         if (node) {
             while (node.original !== undefined) {
                 node = node.original;
             }
         }
 
-        return node;
+        return !nodeTest || nodeTest(node) ? node : undefined;
     }
 
     /**
@@ -3506,9 +3508,20 @@ namespace ts {
         return positionIsSynthesized(range.pos) ? -1 : skipTrivia(sourceFile.text, range.pos);
     }
 
-    export function collectExternalModuleInfo(sourceFile: SourceFile) {
+    export interface ExternalModuleInfo {
+        externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[]; // imports of other external modules
+        exportSpecifiers: Map<ExportSpecifier[]>; // export specifiers by name
+        exportedBindings: Map<Identifier[]>; // exported names of local declarations
+        exportedNames: Identifier[]; // all exported names local to module
+        exportEquals: ExportAssignment | undefined; // an export= declaration if one was present
+        hasExportStarsToExportValues: boolean; // whether this module contains export*
+    }
+
+    export function collectExternalModuleInfo(sourceFile: SourceFile, resolver: EmitResolver): ExternalModuleInfo {
         const externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[] = [];
         const exportSpecifiers = createMap<ExportSpecifier[]>();
+        const exportedBindings = createMap<Identifier[]>();
+        const uniqueExports = createMap<Identifier>();
         let exportEquals: ExportAssignment = undefined;
         let hasExportStarsToExportValues = false;
         for (const node of sourceFile.statements) {
@@ -3526,6 +3539,16 @@ namespace ts {
                         // import x = require("mod")
                         externalImports.push(<ImportEqualsDeclaration>node);
                     }
+
+                    if (hasModifier(node, ModifierFlags.Export)) {
+                        // export import x = ...
+                        const name = (<ImportEqualsDeclaration>node).name;
+                        if (!uniqueExports[name.text]) {
+                            multiMapAdd(exportedBindings, getOriginalNodeId(node), name);
+                            uniqueExports[name.text] = name;
+                        }
+                    }
+
                     break;
 
                 case SyntaxKind.ExportDeclaration:
@@ -3543,8 +3566,19 @@ namespace ts {
                     else {
                         // export { x, y }
                         for (const specifier of (<ExportDeclaration>node).exportClause.elements) {
-                            const name = (specifier.propertyName || specifier.name).text;
-                            (exportSpecifiers[name] || (exportSpecifiers[name] = [])).push(specifier);
+                            if (!uniqueExports[specifier.name.text]) {
+                                const name = specifier.propertyName || specifier.name;
+                                multiMapAdd(exportSpecifiers, name.text, specifier);
+
+                                const decl = resolver.getReferencedImportDeclaration(name)
+                                    || resolver.getReferencedValueDeclaration(name);
+
+                                if (decl) {
+                                    multiMapAdd(exportedBindings, getOriginalNodeId(decl), specifier.name);
+                                }
+
+                                uniqueExports[specifier.name.text] = specifier.name;
+                            }
                         }
                     }
                     break;
@@ -3555,10 +3589,95 @@ namespace ts {
                         exportEquals = <ExportAssignment>node;
                     }
                     break;
+
+                case SyntaxKind.VariableDeclaration:
+                    // export var x
+                    if (hasModifier(node, ModifierFlags.Export)) {
+                        for (const decl of (<VariableStatement>node).declarationList.declarations) {
+                            collectExportedVariableInfo(decl, exportedBindings, uniqueExports);
+                        }
+                    }
+                    break;
+
+                case SyntaxKind.FunctionDeclaration:
+                    if (hasModifier(node, ModifierFlags.Export)) {
+                        if (hasModifier(node, ModifierFlags.Default)) {
+                            // export default function() { }
+                            if (!uniqueExports["default"]) {
+                                multiMapAdd(exportedBindings, getOriginalNodeId(node), getDeclarationName(<FunctionDeclaration>node));
+                                uniqueExports["default"] = createIdentifier("default");
+                            }
+                        }
+                        else {
+                            // export function x() { }
+                            const name = (<FunctionDeclaration>node).name;
+                            if (!uniqueExports[name.text]) {
+                                multiMapAdd(exportedBindings, getOriginalNodeId(node), name);
+                                uniqueExports[name.text] = name;
+                            }
+                        }
+                    }
+                    break;
+
+                case SyntaxKind.ClassDeclaration:
+                    if (hasModifier(node, ModifierFlags.Export)) {
+                        if (hasModifier(node, ModifierFlags.Default)) {
+                            // export default class { }
+                            if (!uniqueExports["default"]) {
+                                multiMapAdd(exportedBindings, getOriginalNodeId(node), getDeclarationName(<ClassDeclaration>node));
+                            }
+                        }
+                        else {
+                            // export class x { }
+                            const name = (<ClassDeclaration>node).name;
+                            if (!uniqueExports[name.text]) {
+                                multiMapAdd(exportedBindings, getOriginalNodeId(node), name);
+                                uniqueExports[name.text] = name;
+                            }
+                        }
+                    }
+                    break;
             }
         }
 
-        return { externalImports, exportSpecifiers, exportEquals, hasExportStarsToExportValues };
+        const exportedNames: Identifier[] = [];
+        for (const key in uniqueExports) {
+            exportedNames.push(uniqueExports[key]);
+        }
+
+        return { externalImports, exportSpecifiers, exportEquals, hasExportStarsToExportValues, exportedBindings, exportedNames };
+    }
+
+    function collectExportedVariableInfo(decl: VariableDeclaration | BindingElement, exportedNames: Map<Identifier[]>, uniqueExports: Map<Identifier>) {
+        if (isBindingPattern(decl.name)) {
+            for (const element of decl.name.elements) {
+                if (!isOmittedExpression(element)) {
+                    collectExportedVariableInfo(element, exportedNames, uniqueExports);
+                }
+            }
+        }
+        else if (!isGeneratedIdentifier(decl.name)) {
+            if (!uniqueExports[decl.name.text]) {
+                multiMapAdd(exportedNames, getOriginalNodeId(decl), decl.name);
+                uniqueExports[decl.name.text] = decl.name;
+            }
+        }
+    }
+
+    /**
+     * Determines whether a name was originally the declaration name of an enum or namespace
+     * declaration.
+     */
+    export function isDeclarationNameOfEnumOrNamespace(node: Identifier) {
+        const parseNode = getParseTreeNode(node);
+        if (parseNode) {
+            switch (parseNode.parent.kind) {
+                case SyntaxKind.EnumDeclaration:
+                case SyntaxKind.ModuleDeclaration:
+                    return parseNode === (<EnumDeclaration | ModuleDeclaration>parseNode.parent).name;
+            }
+        }
+        return false;
     }
 
     export function getInitializedVariables(node: VariableDeclarationList) {
@@ -4041,7 +4160,8 @@ namespace ts {
             || kind === SyntaxKind.VariableStatement
             || kind === SyntaxKind.WhileStatement
             || kind === SyntaxKind.WithStatement
-            || kind === SyntaxKind.NotEmittedStatement;
+            || kind === SyntaxKind.NotEmittedStatement
+            || kind === SyntaxKind.EndOfDeclarationMarker;
     }
 
     export function isDeclaration(node: Node): node is Declaration {
diff --git a/tests/baselines/reference/ExportAssignment7.js b/tests/baselines/reference/ExportAssignment7.js
index bc7cee12b1dca..461631e0e7d0d 100644
--- a/tests/baselines/reference/ExportAssignment7.js
+++ b/tests/baselines/reference/ExportAssignment7.js
@@ -11,5 +11,4 @@ var C = (function () {
     }
     return C;
 }());
-exports.C = C;
 module.exports = B;
diff --git a/tests/baselines/reference/ExportAssignment8.js b/tests/baselines/reference/ExportAssignment8.js
index e31a38c651c75..d09630080125a 100644
--- a/tests/baselines/reference/ExportAssignment8.js
+++ b/tests/baselines/reference/ExportAssignment8.js
@@ -11,5 +11,4 @@ var C = (function () {
     }
     return C;
 }());
-exports.C = C;
 module.exports = B;
diff --git a/tests/baselines/reference/amdImportNotAsPrimaryExpression.js b/tests/baselines/reference/amdImportNotAsPrimaryExpression.js
index efd1c2aa909fa..a0bd7c83d64e5 100644
--- a/tests/baselines/reference/amdImportNotAsPrimaryExpression.js
+++ b/tests/baselines/reference/amdImportNotAsPrimaryExpression.js
@@ -40,8 +40,8 @@ define(["require", "exports"], function (require, exports) {
         }
         return C1;
     }());
-    exports.C1 = C1;
     C1.s1 = true;
+    exports.C1 = C1;
     var E1;
     (function (E1) {
         E1[E1["A"] = 0] = "A";
diff --git a/tests/baselines/reference/commonJSImportAsPrimaryExpression.js b/tests/baselines/reference/commonJSImportAsPrimaryExpression.js
index d22b5b2855b22..b8cf42ea7622a 100644
--- a/tests/baselines/reference/commonJSImportAsPrimaryExpression.js
+++ b/tests/baselines/reference/commonJSImportAsPrimaryExpression.js
@@ -21,8 +21,8 @@ var C1 = (function () {
     }
     return C1;
 }());
-exports.C1 = C1;
 C1.s1 = true;
+exports.C1 = C1;
 //// [foo_1.js]
 "use strict";
 var foo = require("./foo_0");
diff --git a/tests/baselines/reference/commonJSImportNotAsPrimaryExpression.js b/tests/baselines/reference/commonJSImportNotAsPrimaryExpression.js
index a66d04a2ddedb..eb77d1baa3cb5 100644
--- a/tests/baselines/reference/commonJSImportNotAsPrimaryExpression.js
+++ b/tests/baselines/reference/commonJSImportNotAsPrimaryExpression.js
@@ -39,8 +39,8 @@ var C1 = (function () {
     }
     return C1;
 }());
-exports.C1 = C1;
 C1.s1 = true;
+exports.C1 = C1;
 var E1;
 (function (E1) {
     E1[E1["A"] = 0] = "A";
diff --git a/tests/baselines/reference/decoratedClassExportsCommonJS1.js b/tests/baselines/reference/decoratedClassExportsCommonJS1.js
index 9674d7853d5d8..2b20c7ec168b8 100644
--- a/tests/baselines/reference/decoratedClassExportsCommonJS1.js
+++ b/tests/baselines/reference/decoratedClassExportsCommonJS1.js
@@ -17,12 +17,12 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
 var __metadata = (this && this.__metadata) || function (k, v) {
     if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
 };
-let Testing123_1 = class Testing123 {
+let Testing123 = Testing123_1 = class Testing123 {
 };
-let Testing123 = Testing123_1;
 Testing123.prop1 = Testing123_1.prop0;
 Testing123 = Testing123_1 = __decorate([
     Something({ v: () => Testing123_1 }),
     __metadata("design:paramtypes", [])
 ], Testing123);
 exports.Testing123 = Testing123;
+var Testing123_1;
diff --git a/tests/baselines/reference/decoratedClassExportsCommonJS2.js b/tests/baselines/reference/decoratedClassExportsCommonJS2.js
index 3ca6fa2d70e31..9e8b8693109b6 100644
--- a/tests/baselines/reference/decoratedClassExportsCommonJS2.js
+++ b/tests/baselines/reference/decoratedClassExportsCommonJS2.js
@@ -16,11 +16,11 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
 var __metadata = (this && this.__metadata) || function (k, v) {
     if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
 };
-let Testing123_1 = class Testing123 {
+let Testing123 = Testing123_1 = class Testing123 {
 };
-let Testing123 = Testing123_1;
 Testing123 = Testing123_1 = __decorate([
     Something({ v: () => Testing123_1 }),
     __metadata("design:paramtypes", [])
 ], Testing123);
 exports.Testing123 = Testing123;
+var Testing123_1;
diff --git a/tests/baselines/reference/decoratedClassExportsSystem1.js b/tests/baselines/reference/decoratedClassExportsSystem1.js
index 43a4421642e1a..6f7fcbd144aae 100644
--- a/tests/baselines/reference/decoratedClassExportsSystem1.js
+++ b/tests/baselines/reference/decoratedClassExportsSystem1.js
@@ -21,13 +21,12 @@ System.register([], function (exports_1, context_1) {
         if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
     };
     var __moduleName = context_1 && context_1.id;
-    var Testing123_1, Testing123;
+    var Testing123, Testing123_1;
     return {
         setters: [],
         execute: function () {
-            Testing123_1 = class Testing123 {
+            Testing123 = Testing123_1 = class Testing123 {
             };
-            Testing123 = Testing123_1;
             Testing123.prop1 = Testing123_1.prop0;
             Testing123 = Testing123_1 = __decorate([
                 Something({ v: () => Testing123_1 }),
diff --git a/tests/baselines/reference/decoratedClassExportsSystem2.js b/tests/baselines/reference/decoratedClassExportsSystem2.js
index cbb592539cf7d..2a1a394a1f39c 100644
--- a/tests/baselines/reference/decoratedClassExportsSystem2.js
+++ b/tests/baselines/reference/decoratedClassExportsSystem2.js
@@ -18,13 +18,12 @@ System.register([], function (exports_1, context_1) {
         if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
     };
     var __moduleName = context_1 && context_1.id;
-    var Testing123_1, Testing123;
+    var Testing123, Testing123_1;
     return {
         setters: [],
         execute: function () {
-            Testing123_1 = class Testing123 {
+            Testing123 = Testing123_1 = class Testing123 {
             };
-            Testing123 = Testing123_1;
             Testing123 = Testing123_1 = __decorate([
                 Something({ v: () => Testing123_1 }),
                 __metadata("design:paramtypes", [])
diff --git a/tests/baselines/reference/decoratorMetadataOnInferredType.js b/tests/baselines/reference/decoratorMetadataOnInferredType.js
index 0c63bcf49daea..43cdaa79ab8c4 100644
--- a/tests/baselines/reference/decoratorMetadataOnInferredType.js
+++ b/tests/baselines/reference/decoratorMetadataOnInferredType.js
@@ -33,8 +33,8 @@ var B = (function () {
     }
     return B;
 }());
-exports.B = B;
 __decorate([
     decorator,
     __metadata("design:type", Object)
 ], B.prototype, "x", void 0);
+exports.B = B;
diff --git a/tests/baselines/reference/decoratorMetadataWithConstructorType.js b/tests/baselines/reference/decoratorMetadataWithConstructorType.js
index 49b72e39a097b..2c14c9b5bdabb 100644
--- a/tests/baselines/reference/decoratorMetadataWithConstructorType.js
+++ b/tests/baselines/reference/decoratorMetadataWithConstructorType.js
@@ -33,8 +33,8 @@ var B = (function () {
     }
     return B;
 }());
-exports.B = B;
 __decorate([
     decorator,
     __metadata("design:type", A)
 ], B.prototype, "x", void 0);
+exports.B = B;
diff --git a/tests/baselines/reference/decoratorOnClass5.es6.js b/tests/baselines/reference/decoratorOnClass5.es6.js
index e34740d651721..426a93668e7e0 100644
--- a/tests/baselines/reference/decoratorOnClass5.es6.js
+++ b/tests/baselines/reference/decoratorOnClass5.es6.js
@@ -16,12 +16,12 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
     else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
     return c > 3 && r && Object.defineProperty(target, key, r), r;
 };
-let C_1 = class C {
+let C = C_1 = class C {
     static x() { return C_1.y; }
 };
-let C = C_1;
 C.y = 1;
 C = C_1 = __decorate([
     dec
 ], C);
 let c = new C();
+var C_1;
diff --git a/tests/baselines/reference/decoratorOnClass6.es6.js b/tests/baselines/reference/decoratorOnClass6.es6.js
index fff39d8591661..7da4a20bb9331 100644
--- a/tests/baselines/reference/decoratorOnClass6.es6.js
+++ b/tests/baselines/reference/decoratorOnClass6.es6.js
@@ -16,13 +16,13 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
     else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
     return c > 3 && r && Object.defineProperty(target, key, r), r;
 };
-let C_1 = class C {
+let C = C_1 = class C {
     static x() { return C_1.y; }
 };
-let C = C_1;
 C.y = 1;
 C = C_1 = __decorate([
     dec
 ], C);
 export { C };
 let c = new C();
+var C_1;
diff --git a/tests/baselines/reference/decoratorOnClass7.es6.js b/tests/baselines/reference/decoratorOnClass7.es6.js
index 7f111ea4abf97..92ee02c899e4f 100644
--- a/tests/baselines/reference/decoratorOnClass7.es6.js
+++ b/tests/baselines/reference/decoratorOnClass7.es6.js
@@ -16,13 +16,13 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
     else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
     return c > 3 && r && Object.defineProperty(target, key, r), r;
 };
-let C_1 = class C {
+let C = C_1 = class C {
     static x() { return C_1.y; }
 };
-let C = C_1;
 C.y = 1;
 C = C_1 = __decorate([
     dec
 ], C);
 export default C;
 let c = new C();
+var C_1;
diff --git a/tests/baselines/reference/defaultExportsCannotMerge02.js b/tests/baselines/reference/defaultExportsCannotMerge02.js
index ae5701b86bc79..f327c62e5714e 100644
--- a/tests/baselines/reference/defaultExportsCannotMerge02.js
+++ b/tests/baselines/reference/defaultExportsCannotMerge02.js
@@ -33,7 +33,7 @@ var Decl = (function () {
     return Decl;
 }());
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.default = exports.Decl;
+exports.default = Decl;
 //// [m2.js]
 "use strict";
 var m1_1 = require("m1");
diff --git a/tests/baselines/reference/defaultExportsCannotMerge04.js b/tests/baselines/reference/defaultExportsCannotMerge04.js
index ef8d6853d9809..7c9bd88bc16df 100644
--- a/tests/baselines/reference/defaultExportsCannotMerge04.js
+++ b/tests/baselines/reference/defaultExportsCannotMerge04.js
@@ -18,7 +18,7 @@ export interface Foo {
 function Foo() {
 }
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.default = exports.Foo;
+exports.default = Foo;
 var Foo;
 (function (Foo) {
-})(exports.Foo || (exports.Foo = {}));
+})(Foo || (Foo = {}));
diff --git a/tests/baselines/reference/dottedNamesInSystem.js b/tests/baselines/reference/dottedNamesInSystem.js
index c4bb44f03cf2c..e337e8cb1238a 100644
--- a/tests/baselines/reference/dottedNamesInSystem.js
+++ b/tests/baselines/reference/dottedNamesInSystem.js
@@ -28,7 +28,7 @@ System.register([], function (exports_1, context_1) {
                         C.foo = foo;
                     })(C = B.C || (B.C = {}));
                 })(B = A.B || (A.B = {}));
-            })(A = A || (A = {}));
+            })(A || (A = {}));
             exports_1("A", A);
         }
     };
diff --git a/tests/baselines/reference/es3defaultAliasIsQuoted.js b/tests/baselines/reference/es3defaultAliasIsQuoted.js
index 2ce6113b4fe25..89fd0c47a7e94 100644
--- a/tests/baselines/reference/es3defaultAliasIsQuoted.js
+++ b/tests/baselines/reference/es3defaultAliasIsQuoted.js
@@ -21,8 +21,8 @@ var Foo = (function () {
     }
     return Foo;
 }());
-exports.Foo = Foo;
 Foo.CONSTANT = "Foo";
+exports.Foo = Foo;
 function assert(value) {
     if (!value)
         throw new Error("Assertion failed!");
diff --git a/tests/baselines/reference/es5ExportEquals.js b/tests/baselines/reference/es5ExportEquals.js
index 4697c61976b88..3a1ae6fe242c2 100644
--- a/tests/baselines/reference/es5ExportEquals.js
+++ b/tests/baselines/reference/es5ExportEquals.js
@@ -8,7 +8,6 @@ export = f;
 //// [es5ExportEquals.js]
 "use strict";
 function f() { }
-exports.f = f;
 module.exports = f;
 
 
diff --git a/tests/baselines/reference/es6modulekindWithES5Target.js b/tests/baselines/reference/es6modulekindWithES5Target.js
index 10d9cd2e36f32..66967cbc89fc9 100644
--- a/tests/baselines/reference/es6modulekindWithES5Target.js
+++ b/tests/baselines/reference/es6modulekindWithES5Target.js
@@ -27,13 +27,14 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
     else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
     return c > 3 && r && Object.defineProperty(target, key, r), r;
 };
-export var C = (function () {
+var C = (function () {
     function C() {
         this.p = 1;
     }
     C.prototype.method = function () { };
     return C;
 }());
+export { C };
 C.s = 0;
 export { C as C2 };
 var D = (function () {
diff --git a/tests/baselines/reference/es6modulekindWithES5Target12.js b/tests/baselines/reference/es6modulekindWithES5Target12.js
index 316718e6f8083..74646f73e556a 100644
--- a/tests/baselines/reference/es6modulekindWithES5Target12.js
+++ b/tests/baselines/reference/es6modulekindWithES5Target12.js
@@ -38,11 +38,12 @@ export namespace F {
 }
 
 //// [es6modulekindWithES5Target12.js]
-export var C = (function () {
+var C = (function () {
     function C() {
     }
     return C;
 }());
+export { C };
 (function (C) {
     C.x = 1;
 })(C || (C = {}));
diff --git a/tests/baselines/reference/exportAssignmentWithExports.js b/tests/baselines/reference/exportAssignmentWithExports.js
index 626e7881548d7..8441b7b4320d9 100644
--- a/tests/baselines/reference/exportAssignmentWithExports.js
+++ b/tests/baselines/reference/exportAssignmentWithExports.js
@@ -10,7 +10,6 @@ var C = (function () {
     }
     return C;
 }());
-exports.C = C;
 var D = (function () {
     function D() {
     }
diff --git a/tests/baselines/reference/exportEqualsAmd.js b/tests/baselines/reference/exportEqualsAmd.js
index 385012a6e0f0f..8b66b8896e315 100644
--- a/tests/baselines/reference/exportEqualsAmd.js
+++ b/tests/baselines/reference/exportEqualsAmd.js
@@ -4,6 +4,6 @@ export = { ["hi"]: "there" };
 //// [exportEqualsAmd.js]
 define(["require", "exports"], function (require, exports) {
     "use strict";
-    return _a = {}, _a["hi"] = "there", _a;
     var _a;
+    return _a = {}, _a["hi"] = "there", _a;
 });
diff --git a/tests/baselines/reference/exportEqualsCommonJs.js b/tests/baselines/reference/exportEqualsCommonJs.js
index 01b7a43b31033..03202239b1727 100644
--- a/tests/baselines/reference/exportEqualsCommonJs.js
+++ b/tests/baselines/reference/exportEqualsCommonJs.js
@@ -3,5 +3,5 @@ export = { ["hi"]: "there" };
 
 //// [exportEqualsCommonJs.js]
 "use strict";
-module.exports = (_a = {}, _a["hi"] = "there", _a);
 var _a;
+module.exports = (_a = {}, _a["hi"] = "there", _a);
diff --git a/tests/baselines/reference/exportEqualsUmd.js b/tests/baselines/reference/exportEqualsUmd.js
index cd4c99f504d12..500c8795dc7c0 100644
--- a/tests/baselines/reference/exportEqualsUmd.js
+++ b/tests/baselines/reference/exportEqualsUmd.js
@@ -11,6 +11,6 @@ export = { ["hi"]: "there" };
     }
 })(["require", "exports"], function (require, exports) {
     "use strict";
-    return _a = {}, _a["hi"] = "there", _a;
     var _a;
+    return _a = {}, _a["hi"] = "there", _a;
 });
diff --git a/tests/baselines/reference/externModule.js b/tests/baselines/reference/externModule.js
index ff83d07ef981b..f7edc1283df8f 100644
--- a/tests/baselines/reference/externModule.js
+++ b/tests/baselines/reference/externModule.js
@@ -43,11 +43,12 @@ n=XDate.UTC(1964,2,1);
 declare;
 module;
 {
-    export var XDate = (function () {
+    var XDate = (function () {
         function XDate() {
         }
         return XDate;
     }());
+    export { XDate };
 }
 var d = new XDate();
 d.getDay();
diff --git a/tests/baselines/reference/importImportOnlyModule.js b/tests/baselines/reference/importImportOnlyModule.js
index 38ffc08d65e00..013999321f959 100644
--- a/tests/baselines/reference/importImportOnlyModule.js
+++ b/tests/baselines/reference/importImportOnlyModule.js
@@ -24,8 +24,8 @@ define(["require", "exports"], function (require, exports) {
         }
         return C1;
     }());
-    exports.C1 = C1;
     C1.s1 = true;
+    exports.C1 = C1;
 });
 //// [foo_1.js]
 define(["require", "exports"], function (require, exports) {
diff --git a/tests/baselines/reference/innerModExport1.js b/tests/baselines/reference/innerModExport1.js
index cbeced3704629..285120c7462cd 100644
--- a/tests/baselines/reference/innerModExport1.js
+++ b/tests/baselines/reference/innerModExport1.js
@@ -27,10 +27,9 @@ var Outer;
     module;
     {
         var non_export_var = 0;
-        Outer.export_var = 1;
+        export var export_var = 1;
         function NonExportFunc() { return 0; }
-        function ExportFunc() { return 0; }
-        Outer.ExportFunc = ExportFunc;
+        export function ExportFunc() { return 0; }
     }
     Outer.outer_var_export = 0;
     function outerFuncExport() { return 0; }
diff --git a/tests/baselines/reference/innerModExport2.js b/tests/baselines/reference/innerModExport2.js
index a1526daf6f3d9..2024cd8284fa9 100644
--- a/tests/baselines/reference/innerModExport2.js
+++ b/tests/baselines/reference/innerModExport2.js
@@ -28,10 +28,9 @@ var Outer;
     module;
     {
         var non_export_var = 0;
-        Outer.export_var = 1;
+        export var export_var = 1;
         function NonExportFunc() { return 0; }
-        function ExportFunc() { return 0; }
-        Outer.ExportFunc = ExportFunc;
+        export function ExportFunc() { return 0; }
     }
     var export_var;
     Outer.outer_var_export = 0;
diff --git a/tests/baselines/reference/invalidModuleWithVarStatements.js b/tests/baselines/reference/invalidModuleWithVarStatements.js
index ce5fbd54ed152..caa6b24f00ff6 100644
--- a/tests/baselines/reference/invalidModuleWithVarStatements.js
+++ b/tests/baselines/reference/invalidModuleWithVarStatements.js
@@ -39,11 +39,11 @@ var Y2;
 })(Y2 || (Y2 = {}));
 var Y4;
 (function (Y4) {
-    static var x = 0;
+    var x = 0;
 })(Y4 || (Y4 = {}));
 var YY;
 (function (YY) {
-    static function fn(x) { }
+    function fn(x) { }
 })(YY || (YY = {}));
 var YY2;
 (function (YY2) {
diff --git a/tests/baselines/reference/moduleElementsInWrongContext3.js b/tests/baselines/reference/moduleElementsInWrongContext3.js
index 76220eab251a1..851ad654494b4 100644
--- a/tests/baselines/reference/moduleElementsInWrongContext3.js
+++ b/tests/baselines/reference/moduleElementsInWrongContext3.js
@@ -47,9 +47,8 @@ var P;
             }
             return C;
         }());
-        P.C = C;
-        function bee() { }
-        P.bee = bee;
+        export default C;
+        export function bee() { }
         import I2 = require("foo");
         import * as Foo from "ambient";
         import bar from "ambient";
diff --git a/tests/baselines/reference/outModuleConcatAmd.js.map b/tests/baselines/reference/outModuleConcatAmd.js.map
index e987d5deb8a10..9187aca0646db 100644
--- a/tests/baselines/reference/outModuleConcatAmd.js.map
+++ b/tests/baselines/reference/outModuleConcatAmd.js.map
@@ -1,2 +1,2 @@
 //// [all.js.map]
-{"version":3,"file":"all.js","sourceRoot":"","sources":["tests/cases/compiler/ref/a.ts","tests/cases/compiler/b.ts"],"names":[],"mappings":";;;;;;;IACA;QAAA;QAAiB,CAAC;QAAD,QAAC;IAAD,CAAC,AAAlB,IAAkB;IAAlB,cAAkB;;;;ICAlB;QAAuB,qBAAC;QAAxB;;QAA2B,CAAC;QAAD,QAAC;IAAD,CAAC,AAA5B,CAAuB,KAAC,GAAI;IAA5B,cAA4B"}
\ No newline at end of file
+{"version":3,"file":"all.js","sourceRoot":"","sources":["tests/cases/compiler/ref/a.ts","tests/cases/compiler/b.ts"],"names":[],"mappings":";;;;;;;IACA;QAAA;QAAiB,CAAC;QAAD,QAAC;IAAD,CAAC,AAAlB,IAAkB;IAAL,cAAC;;;;ICAd;QAAuB,qBAAC;QAAxB;;QAA2B,CAAC;QAAD,QAAC;IAAD,CAAC,AAA5B,CAAuB,KAAC,GAAI;IAAf,cAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/outModuleConcatAmd.sourcemap.txt b/tests/baselines/reference/outModuleConcatAmd.sourcemap.txt
index 1bfda04977630..34ab74816ade5 100644
--- a/tests/baselines/reference/outModuleConcatAmd.sourcemap.txt
+++ b/tests/baselines/reference/outModuleConcatAmd.sourcemap.txt
@@ -64,9 +64,9 @@ sourceFile:tests/cases/compiler/ref/a.ts
 1->^^^^
 2 >    ^^^^^^^^^^^^^^
 1->
-2 >    export class A { }
-1->Emitted(13, 5) Source(2, 1) + SourceIndex(0)
-2 >Emitted(13, 19) Source(2, 19) + SourceIndex(0)
+2 >    A
+1->Emitted(13, 5) Source(2, 14) + SourceIndex(0)
+2 >Emitted(13, 19) Source(2, 15) + SourceIndex(0)
 ---
 -------------------------------------------------------------------
 emittedFile:all.js
@@ -139,9 +139,9 @@ sourceFile:tests/cases/compiler/b.ts
 1->^^^^
 2 >    ^^^^^^^^^^^^^^
 1->
-2 >    export class B extends A { }
-1->Emitted(24, 5) Source(2, 1) + SourceIndex(1)
-2 >Emitted(24, 19) Source(2, 29) + SourceIndex(1)
+2 >    B
+1->Emitted(24, 5) Source(2, 14) + SourceIndex(1)
+2 >Emitted(24, 19) Source(2, 15) + SourceIndex(1)
 ---
 >>>});
 >>>//# sourceMappingURL=all.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/outModuleTripleSlashRefs.js.map b/tests/baselines/reference/outModuleTripleSlashRefs.js.map
index 45d5799045001..5ccc59aeabfb3 100644
--- a/tests/baselines/reference/outModuleTripleSlashRefs.js.map
+++ b/tests/baselines/reference/outModuleTripleSlashRefs.js.map
@@ -1,2 +1,2 @@
 //// [all.js.map]
-{"version":3,"file":"all.js","sourceRoot":"","sources":["tests/cases/compiler/ref/b.ts","tests/cases/compiler/ref/a.ts","tests/cases/compiler/b.ts"],"names":[],"mappings":";;;;;AAAA,iCAAiC;AACjC;IAAA;IAEA,CAAC;IAAD,UAAC;AAAD,CAAC,AAFD,IAEC;;;ICFD,+BAA+B;IAC/B;QAAA;QAEA,CAAC;QAAD,QAAC;IAAD,CAAC,AAFD,IAEC;IAFD,cAEC;;;;ICHD;QAAuB,qBAAC;QAAxB;;QAA2B,CAAC;QAAD,QAAC;IAAD,CAAC,AAA5B,CAAuB,KAAC,GAAI;IAA5B,cAA4B"}
\ No newline at end of file
+{"version":3,"file":"all.js","sourceRoot":"","sources":["tests/cases/compiler/ref/b.ts","tests/cases/compiler/ref/a.ts","tests/cases/compiler/b.ts"],"names":[],"mappings":";;;;;AAAA,iCAAiC;AACjC;IAAA;IAEA,CAAC;IAAD,UAAC;AAAD,CAAC,AAFD,IAEC;;;ICFD,+BAA+B;IAC/B;QAAA;QAEA,CAAC;QAAD,QAAC;IAAD,CAAC,AAFD,IAEC;IAFY,cAAC;;;;ICDd;QAAuB,qBAAC;QAAxB;;QAA2B,CAAC;QAAD,QAAC;IAAD,CAAC,AAA5B,CAAuB,KAAC,GAAI;IAAf,cAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/outModuleTripleSlashRefs.sourcemap.txt b/tests/baselines/reference/outModuleTripleSlashRefs.sourcemap.txt
index 482c898e0cb03..ce41bae6de338 100644
--- a/tests/baselines/reference/outModuleTripleSlashRefs.sourcemap.txt
+++ b/tests/baselines/reference/outModuleTripleSlashRefs.sourcemap.txt
@@ -138,11 +138,9 @@ sourceFile:tests/cases/compiler/ref/a.ts
 1->^^^^
 2 >    ^^^^^^^^^^^^^^
 1->
-2 >    export class A {
-  >    	member: typeof GlobalFoo;
-  >    }
-1->Emitted(20, 5) Source(3, 1) + SourceIndex(1)
-2 >Emitted(20, 19) Source(5, 2) + SourceIndex(1)
+2 >    A
+1->Emitted(20, 5) Source(3, 14) + SourceIndex(1)
+2 >Emitted(20, 19) Source(3, 15) + SourceIndex(1)
 ---
 -------------------------------------------------------------------
 emittedFile:all.js
@@ -215,9 +213,9 @@ sourceFile:tests/cases/compiler/b.ts
 1->^^^^
 2 >    ^^^^^^^^^^^^^^
 1->
-2 >    export class B extends A { }
-1->Emitted(31, 5) Source(2, 1) + SourceIndex(2)
-2 >Emitted(31, 19) Source(2, 29) + SourceIndex(2)
+2 >    B
+1->Emitted(31, 5) Source(2, 14) + SourceIndex(2)
+2 >Emitted(31, 19) Source(2, 15) + SourceIndex(2)
 ---
 >>>});
 >>>//# sourceMappingURL=all.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/parserExportAssignment7.js b/tests/baselines/reference/parserExportAssignment7.js
index f359ada1e91ba..dd6750bec323c 100644
--- a/tests/baselines/reference/parserExportAssignment7.js
+++ b/tests/baselines/reference/parserExportAssignment7.js
@@ -11,5 +11,4 @@ var C = (function () {
     }
     return C;
 }());
-exports.C = C;
 module.exports = B;
diff --git a/tests/baselines/reference/parserExportAssignment8.js b/tests/baselines/reference/parserExportAssignment8.js
index 16a50a30b3c52..07ff257fb6193 100644
--- a/tests/baselines/reference/parserExportAssignment8.js
+++ b/tests/baselines/reference/parserExportAssignment8.js
@@ -11,5 +11,4 @@ var C = (function () {
     }
     return C;
 }());
-exports.C = C;
 module.exports = B;
diff --git a/tests/baselines/reference/privacyCannotNameVarTypeDeclFile.js b/tests/baselines/reference/privacyCannotNameVarTypeDeclFile.js
index cebf700aa5923..c139b6279fd1d 100644
--- a/tests/baselines/reference/privacyCannotNameVarTypeDeclFile.js
+++ b/tests/baselines/reference/privacyCannotNameVarTypeDeclFile.js
@@ -161,11 +161,11 @@ var publicClassWithWithPrivatePropertyTypes = (function () {
     }
     return publicClassWithWithPrivatePropertyTypes;
 }());
-exports.publicClassWithWithPrivatePropertyTypes = publicClassWithWithPrivatePropertyTypes;
 publicClassWithWithPrivatePropertyTypes.myPublicStaticProperty = exporter.createExportedWidget1(); // Error
 publicClassWithWithPrivatePropertyTypes.myPrivateStaticProperty = exporter.createExportedWidget1();
 publicClassWithWithPrivatePropertyTypes.myPublicStaticProperty1 = exporter.createExportedWidget3(); // Error
 publicClassWithWithPrivatePropertyTypes.myPrivateStaticProperty1 = exporter.createExportedWidget3();
+exports.publicClassWithWithPrivatePropertyTypes = publicClassWithWithPrivatePropertyTypes;
 var privateClassWithWithPrivatePropertyTypes = (function () {
     function privateClassWithWithPrivatePropertyTypes() {
         this.myPublicProperty = exporter.createExportedWidget1();
@@ -190,9 +190,9 @@ var publicClassWithPrivateModulePropertyTypes = (function () {
     }
     return publicClassWithPrivateModulePropertyTypes;
 }());
-exports.publicClassWithPrivateModulePropertyTypes = publicClassWithPrivateModulePropertyTypes;
 publicClassWithPrivateModulePropertyTypes.myPublicStaticProperty = exporter.createExportedWidget2(); // Error
 publicClassWithPrivateModulePropertyTypes.myPublicStaticProperty1 = exporter.createExportedWidget4(); // Error
+exports.publicClassWithPrivateModulePropertyTypes = publicClassWithPrivateModulePropertyTypes;
 exports.publicVarWithPrivateModulePropertyTypes = exporter.createExportedWidget2(); // Error
 exports.publicVarWithPrivateModulePropertyTypes1 = exporter.createExportedWidget4(); // Error
 var privateClassWithPrivateModulePropertyTypes = (function () {
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderNoOutdir/amd/ref/m2.js.map b/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderNoOutdir/amd/ref/m2.js.map
index c0e40d9e56ccd..891c03b13f2e4 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderNoOutdir/amd/ref/m2.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderNoOutdir/amd/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderNoOutdir/node/ref/m2.js.map b/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderNoOutdir/node/ref/m2.js.map
index 5f6fc59aa0ec9..30f6e242bc8aa 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderNoOutdir/node/ref/m2.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderNoOutdir/node/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
index c0e40d9e56ccd..891c03b13f2e4 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
index 5f6fc59aa0ec9..30f6e242bc8aa 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
index 06567a4fddd7a..dce282ee37f08 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../ref/m1.ts","../ref/m2.ts","../test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"","sources":["../ref/m1.ts","../ref/m2.ts","../test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map b/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
index d3c0e8697cd34..1316ec7465939 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
@@ -1 +1 @@
-{"version":3,"file":"outAndOutDirFile.js","sourceRoot":"","sources":["../ref/m1.ts","../ref/m2.ts","../test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/amd/diskFile0.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/amd/diskFile0.js.map
index 048c281681125..5db5f8f1bfb54 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/amd/diskFile0.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/amd/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/amd/ref/m1.js.map
index 8e4c69b85cad6..28136d8ffc30a 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/amd/test.js.map
index adc497fc60ffb..dd409b9f2c3b1 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../../test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"","sources":["../../test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFY,gBAAE;IAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/node/diskFile0.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/node/diskFile0.js.map
index 3c11f6387b31a..78b4b9fcfe113 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/node/diskFile0.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/node/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/node/ref/m1.js.map
index f102ba902d9de..f5f5dfcd793b1 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/node/test.js.map
index c84a8f5c8357f..6ba04afda9e2a 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderNoOutdir/node/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../../test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"","sources":["../../test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFY,gBAAE;AAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index 8e4c69b85cad6..28136d8ffc30a 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
index adc497fc60ffb..dd409b9f2c3b1 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../../test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"","sources":["../../test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFY,gBAAE;IAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index 048c281681125..5db5f8f1bfb54 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index f102ba902d9de..f5f5dfcd793b1 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
index c84a8f5c8357f..6ba04afda9e2a 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../../test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"","sources":["../../test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFY,gBAAE;AAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index 3c11f6387b31a..78b4b9fcfe113 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
index 5132061665307..d9151baabe48c 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/amd/m1.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/amd/m1.js.map
index cb20dafd0e677..43b1caa625e11 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/amd/m1.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/amd/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/amd/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/amd/test.js.map
index 379e5b9d7b255..ba491a3c6fa57 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/node/m1.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/node/m1.js.map
index 2a7d88eea534a..02f7bbcbb676a 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/node/m1.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/node/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/node/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/node/test.js.map
index 99658249a0947..766ff607b5482 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
index cb20dafd0e677..43b1caa625e11 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index 379e5b9d7b255..ba491a3c6fa57 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
index 2a7d88eea534a..02f7bbcbb676a 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
index 99658249a0947..766ff607b5482 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
index 105ebefb06ec7..a910ecda80eb3 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../m1.ts","../test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICPU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/amd/ref/m1.js.map
index 9eb482b6438ac..a6d24f0f0204d 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/amd/test.js.map
index 379e5b9d7b255..ba491a3c6fa57 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"","sources":["../test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFY,gBAAE;IAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/node/ref/m1.js.map
index 764cd7db3b422..a23c18711264e 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/node/test.js.map
index 48a5bd9efa8a3..a758d2a1cd03e 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderNoOutdir/node/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AACnB,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
index 9eb482b6438ac..a6d24f0f0204d 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index 379e5b9d7b255..ba491a3c6fa57 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
index 764cd7db3b422..a23c18711264e 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
index 48a5bd9efa8a3..a758d2a1cd03e 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AACnB,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
index 12c15dd7143ae..a3532b9e4ce85 100644
--- a/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/mapRootAbsolutePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../ref/m1.ts","../test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICPU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderNoOutdir/amd/ref/m2.js.map b/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderNoOutdir/amd/ref/m2.js.map
index 26b3342e168e2..0dab151470606 100644
--- a/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderNoOutdir/amd/ref/m2.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderNoOutdir/amd/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderNoOutdir/node/ref/m2.js.map b/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderNoOutdir/node/ref/m2.js.map
index 2137f48e86baf..14104ec68b946 100644
--- a/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderNoOutdir/node/ref/m2.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderNoOutdir/node/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
index 26b3342e168e2..0dab151470606 100644
--- a/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
index 2137f48e86baf..14104ec68b946 100644
--- a/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
index 6e903b7c3707d..d8fff48f73ee0 100644
--- a/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../outputdir_mixed_subfolder/ref/m1.ts","../outputdir_mixed_subfolder/ref/m2.ts","../outputdir_mixed_subfolder/test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"","sources":["../outputdir_mixed_subfolder/ref/m1.ts","../outputdir_mixed_subfolder/ref/m2.ts","../outputdir_mixed_subfolder/test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map b/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
index 4767cb6f4255c..bb9e992d47128 100644
--- a/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
@@ -1 +1 @@
-{"version":3,"file":"outAndOutDirFile.js","sourceRoot":"","sources":["../outputdir_mixed_subfolder/ref/m1.ts","../outputdir_mixed_subfolder/ref/m2.ts","../outputdir_mixed_subfolder/test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
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diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/amd/diskFile0.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/amd/diskFile0.js.map
index 60700ad9d1740..4f51d470c8238 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/amd/diskFile0.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/amd/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../projects/outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/amd/ref/m1.js.map
index 1c3270c1034f3..ee8a26cafcfb4 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/amd/test.js.map
index eb045bec338dd..e60e0fbfa7afc 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/node/diskFile0.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/node/diskFile0.js.map
index 4b491bfe9bb93..3c653ded70050 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/node/diskFile0.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/node/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../projects/outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/node/ref/m1.js.map
index 70285d9fdb407..5f97087307dc1 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../projects/outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/node/test.js.map
index 3b815b5296131..8c64bacf53325 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"","sources":["../../projects/outputdir_module_multifolder/test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFY,gBAAE;AAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index 1c3270c1034f3..ee8a26cafcfb4 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../projects/outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
index eb045bec338dd..e60e0fbfa7afc 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../../projects/outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index 60700ad9d1740..4f51d470c8238 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../projects/outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index 70285d9fdb407..5f97087307dc1 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../projects/outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
index 3b815b5296131..8c64bacf53325 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../../projects/outputdir_module_multifolder/test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index 4b491bfe9bb93..3c653ded70050 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
index e5f2d235179c4..ae1d6457599bf 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/amd/m1.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/amd/m1.js.map
index a623d2caaa6ae..611b73c5c7daf 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/amd/m1.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/amd/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/amd/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/amd/test.js.map
index 579a6a187e3b5..a6d5cebe7f182 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/node/m1.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/node/m1.js.map
index 3a1b7b27c5841..733fa0fc069d6 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/node/m1.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/node/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/node/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/node/test.js.map
index a9589e1fed81f..86cfbeb5b6365 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
index a623d2caaa6ae..611b73c5c7daf 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index 579a6a187e3b5..a6d5cebe7f182 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
index 3a1b7b27c5841..733fa0fc069d6 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
index a9589e1fed81f..86cfbeb5b6365 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
index 5ac4a707e3977..3542da2fe04c7 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/amd/ref/m1.js.map
index 943ae3c5b8ed4..dbfe0b5d9270f 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/amd/test.js.map
index 478bae202d610..a8d6293492c13 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/node/ref/m1.js.map
index 9fea18a6b0227..172c4d4804a02 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/node/test.js.map
index e96624acd65ec..ef62267d9579b 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
index 943ae3c5b8ed4..dbfe0b5d9270f 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../outputdir_module_subfolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index 478bae202d610..a8d6293492c13 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../outputdir_module_subfolder/test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
index 9fea18a6b0227..172c4d4804a02 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../outputdir_module_subfolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../outputdir_module_subfolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
index e96624acd65ec..ef62267d9579b 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
index 4c60ddd29d42e..3096c61023772 100644
--- a/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/mapRootRelativePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../outputdir_module_subfolder/ref/m1.ts","../outputdir_module_subfolder/test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICPU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlMixedSubfolderNoOutdir/amd/ref/m2.js.map b/tests/baselines/reference/project/maprootUrlMixedSubfolderNoOutdir/amd/ref/m2.js.map
index a1de0913da583..c657ed8edce0c 100644
--- a/tests/baselines/reference/project/maprootUrlMixedSubfolderNoOutdir/amd/ref/m2.js.map
+++ b/tests/baselines/reference/project/maprootUrlMixedSubfolderNoOutdir/amd/ref/m2.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlMixedSubfolderNoOutdir/node/ref/m2.js.map b/tests/baselines/reference/project/maprootUrlMixedSubfolderNoOutdir/node/ref/m2.js.map
index 861972de2097e..56f12c2290391 100644
--- a/tests/baselines/reference/project/maprootUrlMixedSubfolderNoOutdir/node/ref/m2.js.map
+++ b/tests/baselines/reference/project/maprootUrlMixedSubfolderNoOutdir/node/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
index a1de0913da583..c657ed8edce0c 100644
--- a/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
index 861972de2097e..56f12c2290391 100644
--- a/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_mixed_subfolder/ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
index 64ad8eb164287..eececdeabfdf5 100644
--- a/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_mixed_subfolder/ref/m1.ts","file:///tests/cases/projects/outputdir_mixed_subfolder/ref/m2.ts","file:///tests/cases/projects/outputdir_mixed_subfolder/test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map b/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
index 63bc893832b84..4bdde30882427 100644
--- a/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
+++ b/tests/baselines/reference/project/maprootUrlMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
@@ -1 +1 @@
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\ No newline at end of file
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diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/amd/diskFile0.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/amd/diskFile0.js.map
index 7a4095156075d..3c1c9b64dc299 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/amd/diskFile0.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/amd/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/amd/ref/m1.js.map
index 3343670eb846e..9bdc7ad550474 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/amd/test.js.map
index 57bb373e05407..3a4d618044a38 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/node/diskFile0.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/node/diskFile0.js.map
index 2da721ff1a0c1..4103e499cbdef 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/node/diskFile0.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/node/diskFile0.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/node/ref/m1.js.map
index c1f7e172c9d2a..49f97b88a3888 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/node/test.js.map
index 474dd10752984..830a0ddd3e5fc 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index 3343670eb846e..9bdc7ad550474 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
index 57bb373e05407..3a4d618044a38 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index 7a4095156075d..3c1c9b64dc299 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index c1f7e172c9d2a..49f97b88a3888 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
index 474dd10752984..830a0ddd3e5fc 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index 2da721ff1a0c1..4103e499cbdef 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
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\ No newline at end of file
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diff --git a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
index 155baf7912b7c..6b934e00e04a4 100644
--- a/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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diff --git a/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/amd/m1.js.map b/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/amd/m1.js.map
index e9f1d54cc8741..eceec7b450a5e 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/amd/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/amd/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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diff --git a/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/amd/test.js.map b/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/amd/test.js.map
index 4c83678dafdb9..d68dbf6eb9e6d 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/amd/test.js.map
@@ -1 +1 @@
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diff --git a/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/node/m1.js.map b/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/node/m1.js.map
index e96a1a904e70c..b9de639cb1d4b 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/node/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/node/m1.js.map
@@ -1 +1 @@
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diff --git a/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/node/test.js.map b/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/node/test.js.map
index e0513a8b07bee..826729aba8749 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSimpleNoOutdir/node/test.js.map
@@ -1 +1 @@
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diff --git a/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map b/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
index e9f1d54cc8741..eceec7b450a5e 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index 4c83678dafdb9..d68dbf6eb9e6d 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map b/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
index e96a1a904e70c..b9de639cb1d4b 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
index e0513a8b07bee..826729aba8749 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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diff --git a/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
index ecbd039578c4a..5396cab1d7c10 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/amd/ref/m1.js.map
index 94b0fd005cbfa..755cc1d0aaf44 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/amd/test.js.map
index 76cc81a74f445..957a73c648a60 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/node/ref/m1.js.map
index 637153a8c7a52..f7e4388304886 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/node/test.js.map
index 99312830f1c3a..8baefdad92bbe 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSubfolderNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
index 94b0fd005cbfa..755cc1d0aaf44 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index 76cc81a74f445..957a73c648a60 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
index 637153a8c7a52..f7e4388304886 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_module_subfolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
index 99312830f1c3a..8baefdad92bbe 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
index d962fcf11cb75..308dbbfaa67c8 100644
--- a/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["file:///tests/cases/projects/outputdir_module_subfolder/ref/m1.ts","file:///tests/cases/projects/outputdir_module_subfolder/test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICPU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderNoOutdir/amd/ref/m2.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderNoOutdir/amd/ref/m2.js.map
index e68a248d5d7dc..a1c9985be48e4 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderNoOutdir/amd/ref/m2.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderNoOutdir/amd/ref/m2.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderNoOutdir/node/ref/m2.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderNoOutdir/node/ref/m2.js.map
index c6ff2cc27ce1e..9ccd44f3a018a 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderNoOutdir/node/ref/m2.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderNoOutdir/node/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
index e68a248d5d7dc..a1c9985be48e4 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
index c6ff2cc27ce1e..9ccd44f3a018a 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
index 35e555688e090..26353fdf396cc 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m1.ts","ref/m2.ts","test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m1.ts","ref/m2.ts","test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
index 19bcc3ee32a40..ec57587014d89 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/amd/diskFile0.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/amd/diskFile0.js.map
index a8c35bc15c620..59ebd34cfe355 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/amd/diskFile0.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/amd/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/amd/ref/m1.js.map
index f1623c531a61c..9afdf343f77e1 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/amd/test.js.map
index b199c0dc1adfd..5000f3a49b9f2 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/node/diskFile0.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/node/diskFile0.js.map
index ef338fcc8875e..866e1007e240c 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/node/diskFile0.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/node/diskFile0.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/node/ref/m1.js.map
index 10777c25bd48c..0f5e28ddbf724 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"http://typescript.codeplex.com/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/node/test.js.map
index dbab2cdf457a2..a39cd29ba7764 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index f1623c531a61c..9afdf343f77e1 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"http://typescript.codeplex.com/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
index b199c0dc1adfd..5000f3a49b9f2 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index a8c35bc15c620..59ebd34cfe355 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index 10777c25bd48c..0f5e28ddbf724 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"http://typescript.codeplex.com/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"http://typescript.codeplex.com/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
index dbab2cdf457a2..a39cd29ba7764 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index ef338fcc8875e..866e1007e240c 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
index 5a120cbe80072..c4facdba9364e 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/amd/m1.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/amd/m1.js.map
index 26e7b01ccdba5..1706ba768171b 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/amd/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/amd/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"http://typescript.codeplex.com/","sources":["m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/amd/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/amd/test.js.map
index f92c491640f17..07e9825a93a7a 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/node/m1.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/node/m1.js.map
index 1b563cf259d6d..d134ab774afff 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/node/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/node/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"http://typescript.codeplex.com/","sources":["m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/node/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/node/test.js.map
index 46e8000caa09c..d07c1aa067898 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
index 26e7b01ccdba5..1706ba768171b 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index f92c491640f17..07e9825a93a7a 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
index 1b563cf259d6d..d134ab774afff 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"http://typescript.codeplex.com/","sources":["m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
index 46e8000caa09c..d07c1aa067898 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
index 28d5511a5ee6f..64c90d05e8808 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/amd/ref/m1.js.map
index 88ce97eeeffa7..7e2762b41a45b 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/amd/test.js.map
index f92c491640f17..07e9825a93a7a 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/node/ref/m1.js.map
index e28d378dfc002..eb8832755683f 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/node/test.js.map
index c956b034f6f9d..4f024886c03bb 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
index 88ce97eeeffa7..7e2762b41a45b 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index f92c491640f17..07e9825a93a7a 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
index e28d378dfc002..eb8832755683f 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
index c956b034f6f9d..4f024886c03bb 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
index a46d68e9b0541..6d26d850e1924 100644
--- a/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/maprootUrlsourcerootUrlModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderNoOutdir/amd/ref/m2.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderNoOutdir/amd/ref/m2.js.map
index fa8f5c4613ebb..e9a80c428b2b4 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderNoOutdir/amd/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderNoOutdir/amd/ref/m2.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderNoOutdir/node/ref/m2.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderNoOutdir/node/ref/m2.js.map
index 3d7c6263ee65c..9f1206b5b146f 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderNoOutdir/node/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderNoOutdir/node/ref/m2.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
index fa8f5c4613ebb..e9a80c428b2b4 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"/tests/cases/projects/outputdir_mixed_subfolder/src/","sources":["ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
index 3d7c6263ee65c..9f1206b5b146f 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
index 28783dfb98362..650c9d1e5d59d 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_mixed_subfolder/src/","sources":["ref/m1.ts","ref/m2.ts","test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
index 1361d34702bd9..6113c44d85d98 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
@@ -1 +1 @@
-{"version":3,"file":"outAndOutDirFile.js","sourceRoot":"/tests/cases/projects/outputdir_mixed_subfolder/src/","sources":["ref/m1.ts","ref/m2.ts","test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
+{"version":3,"file":"outAndOutDirFile.js","sourceRoot":"/tests/cases/projects/outputdir_mixed_subfolder/src/","sources":["ref/m1.ts","ref/m2.ts","test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/amd/diskFile0.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/amd/diskFile0.js.map
index 90860d39fe511..ab7082a2e8e1a 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/amd/diskFile0.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/amd/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/amd/ref/m1.js.map
index b9400dc56242b..6bebdd113b6f3 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/amd/test.js.map
index c50aee154a247..21c996978fdcc 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFY,gBAAE;IAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/node/diskFile0.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/node/diskFile0.js.map
index 11747238b4e01..06c30f32eaf7c 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/node/diskFile0.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/node/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/node/ref/m1.js.map
index 186a8fb37535e..b757263c8667e 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/node/test.js.map
index 450cff64fa113..b123ccf13c8f4 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderNoOutdir/node/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFY,gBAAE;AAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index b9400dc56242b..6bebdd113b6f3 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
index c50aee154a247..21c996978fdcc 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFY,gBAAE;IAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index 90860d39fe511..ab7082a2e8e1a 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index 186a8fb37535e..b757263c8667e 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
index 450cff64fa113..b123ccf13c8f4 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index 11747238b4e01..06c30f32eaf7c 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
index c1afcd019cc18..baeea1e93dc19 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/ref/m1.ts","outputdir_module_multifolder_ref/m2.ts","outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICNU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_multifolder/src/","sources":["outputdir_module_multifolder/ref/m1.ts","outputdir_module_multifolder_ref/m2.ts","outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICNU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFY,gBAAE;IAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/amd/m1.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/amd/m1.js.map
index 3539fcb8d17fa..ffc39be804440 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/amd/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/amd/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/amd/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/amd/test.js.map
index 6355e10911480..6366b8c2d8595 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/amd/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/node/m1.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/node/m1.js.map
index 4347d2eb3ea8c..04bd4e10a3b47 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/node/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/node/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/node/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/node/test.js.map
index 647c302260c3d..9dc457a016701 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleNoOutdir/node/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["test.ts"],"names":[],"mappings":";AAAA,uBAA0B;AACf,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
index 3539fcb8d17fa..ffc39be804440 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index 6355e10911480..6366b8c2d8595 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
index 4347d2eb3ea8c..04bd4e10a3b47 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
index 647c302260c3d..9dc457a016701 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["test.ts"],"names":[],"mappings":";AAAA,uBAA0B;AACf,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["test.ts"],"names":[],"mappings":";AAAA,uBAA0B;AACf,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFY,gBAAE;AAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
index 13c43235b2b95..aa0c2ca28b2a1 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["m1.ts","test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICPU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_simple/src/","sources":["m1.ts","test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICPU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFY,gBAAE;IAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/amd/ref/m1.js.map
index d39589e4f3e7b..cd798e72d8902 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_subfolder/src/","sources":["ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_subfolder/src/","sources":["ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/amd/test.js.map
index 63351122f3e51..6738a871942dd 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_subfolder/src/","sources":["test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/node/ref/m1.js.map
index 4cd2a39d1c1b4..81d64320d78de 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_subfolder/src/","sources":["ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/node/test.js.map
index 993894958b0c9..b2ea9133dfcb9 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderNoOutdir/node/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_subfolder/src/","sources":["test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AACnB,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
index d39589e4f3e7b..cd798e72d8902 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_subfolder/src/","sources":["ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_subfolder/src/","sources":["ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index 63351122f3e51..6738a871942dd 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_subfolder/src/","sources":["test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
index 4cd2a39d1c1b4..81d64320d78de 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"/tests/cases/projects/outputdir_module_subfolder/src/","sources":["ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
index 993894958b0c9..b2ea9133dfcb9 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_subfolder/src/","sources":["test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AACnB,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
index 8dca8ba1a6c53..27b41a837a976 100644
--- a/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourceRootAbsolutePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"/tests/cases/projects/outputdir_module_subfolder/src/","sources":["ref/m1.ts","test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICPU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderNoOutdir/amd/ref/m2.js.map b/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderNoOutdir/amd/ref/m2.js.map
index 5685e41f2bb55..560075530f1ae 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderNoOutdir/amd/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderNoOutdir/amd/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderNoOutdir/node/ref/m2.js.map b/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderNoOutdir/node/ref/m2.js.map
index ea96dcd448f95..27abb47a45bbe 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderNoOutdir/node/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderNoOutdir/node/ref/m2.js.map
@@ -1 +1 @@
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\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
index 5685e41f2bb55..560075530f1ae 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
index ea96dcd448f95..27abb47a45bbe 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
index f9f1f0cd10ebf..9a9586bd20ded 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map b/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
index 19977a8159bae..16e3437b61c59 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
@@ -1 +1 @@
-{"version":3,"file":"outAndOutDirFile.js","sourceRoot":"../src/","sources":["ref/m1.ts","ref/m2.ts","test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
+{"version":3,"file":"outAndOutDirFile.js","sourceRoot":"../src/","sources":["ref/m1.ts","ref/m2.ts","test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/amd/diskFile0.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/amd/diskFile0.js.map
index 0f5e1f6de5c06..6b4ece94c1588 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/amd/diskFile0.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/amd/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/amd/ref/m1.js.map
index 453bd03628699..8271bf25be1bd 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/amd/test.js.map
index 019c9ca53da98..8be239f355348 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFY,gBAAE;IAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/node/diskFile0.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/node/diskFile0.js.map
index d32dfbe0fa377..c7ae549832a57 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/node/diskFile0.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/node/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/node/ref/m1.js.map
index a923e39f3eb8d..37adc61e54fdd 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/node/test.js.map
index faf9a0a8d5059..79b428ca3a1de 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderNoOutdir/node/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFY,gBAAE;AAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index 453bd03628699..8271bf25be1bd 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
index 019c9ca53da98..8be239f355348 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFY,gBAAE;IAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index 0f5e1f6de5c06..6b4ece94c1588 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index a923e39f3eb8d..37adc61e54fdd 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
index faf9a0a8d5059..79b428ca3a1de 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index d32dfbe0fa377..c7ae549832a57 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
index bb8c756a0b94c..4d37f7bfbf5fd 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"../src/","sources":["outputdir_module_multifolder/ref/m1.ts","outputdir_module_multifolder_ref/m2.ts","outputdir_module_multifolder/test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICNU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/amd/m1.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/amd/m1.js.map
index 05d9f8cb3dacd..29c8533aded52 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/amd/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/amd/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/amd/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/amd/test.js.map
index e446b64679d5f..d713f6b7f5ee5 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/node/m1.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/node/m1.js.map
index cca0e50d76211..8086d9c04da05 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/node/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/node/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/node/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/node/test.js.map
index 46798ce7bb461..0d24a0e332a2a 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
index 05d9f8cb3dacd..29c8533aded52 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index e446b64679d5f..d713f6b7f5ee5 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"../src/","sources":["test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
index cca0e50d76211..8086d9c04da05 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
index 46798ce7bb461..0d24a0e332a2a 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
index d70e1816041b8..7e83d4cd269e8 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/amd/ref/m1.js.map
index 43194290d9d6c..91793ab100241 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/amd/test.js.map
index e446b64679d5f..d713f6b7f5ee5 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"../src/","sources":["test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/node/ref/m1.js.map
index cd7b5d10db425..00e388b171e2f 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/node/test.js.map
index b77575bb8b5cf..07178ab519f00 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
index 43194290d9d6c..91793ab100241 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index e446b64679d5f..d713f6b7f5ee5 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"../src/","sources":["test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
index cd7b5d10db425..00e388b171e2f 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"../src/","sources":["ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
index b77575bb8b5cf..07178ab519f00 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
index 3c2cbaf1342d2..223d2cfdad30c 100644
--- a/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourceRootRelativePathModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"../src/","sources":["ref/m1.ts","test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICPU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"../src/","sources":["ref/m1.ts","test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICPU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFY,gBAAE;IAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapMixedSubfolderNoOutdir/amd/ref/m2.js.map b/tests/baselines/reference/project/sourcemapMixedSubfolderNoOutdir/amd/ref/m2.js.map
index b7c7a76331897..c4bc3c327089b 100644
--- a/tests/baselines/reference/project/sourcemapMixedSubfolderNoOutdir/amd/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourcemapMixedSubfolderNoOutdir/amd/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapMixedSubfolderNoOutdir/node/ref/m2.js.map b/tests/baselines/reference/project/sourcemapMixedSubfolderNoOutdir/node/ref/m2.js.map
index 57aea3578c6d5..208dd329040a0 100644
--- a/tests/baselines/reference/project/sourcemapMixedSubfolderNoOutdir/node/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourcemapMixedSubfolderNoOutdir/node/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
index af5f11f8dd381..c0b56df8d9001 100644
--- a/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
index 3d8629098dcc8..5e34d4494ddc1 100644
--- a/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
index 06567a4fddd7a..dce282ee37f08 100644
--- a/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../ref/m1.ts","../ref/m2.ts","../test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"","sources":["../ref/m1.ts","../ref/m2.ts","../test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map b/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
index d3c0e8697cd34..1316ec7465939 100644
--- a/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
+++ b/tests/baselines/reference/project/sourcemapMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
@@ -1 +1 @@
-{"version":3,"file":"outAndOutDirFile.js","sourceRoot":"","sources":["../ref/m1.ts","../ref/m2.ts","../test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
+{"version":3,"file":"outAndOutDirFile.js","sourceRoot":"","sources":["../ref/m1.ts","../ref/m2.ts","../test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/amd/diskFile0.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/amd/diskFile0.js.map
index b7c7a76331897..c4bc3c327089b 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/amd/diskFile0.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/amd/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/amd/ref/m1.js.map
index 41a7fb93ee628..dcdf5faf89716 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/amd/test.js.map
index dc6ab342a5191..096386e968d05 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["test.ts"],"names":[],"mappings":";;IAEW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;IACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/node/diskFile0.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/node/diskFile0.js.map
index 57aea3578c6d5..208dd329040a0 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/node/diskFile0.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/node/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/node/ref/m1.js.map
index 6af45080bd6c1..87fa414a454ee 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/node/test.js.map
index c51718c91d88f..a9dba1be1ddbd 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index a77c789e625bf..2293c1a7c9602 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../../ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../../ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
index 5890568ea24c1..d21a585cc41d5 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index 502b9145dc80d..5d8cf325d5277 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../../outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../../outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index 1bc2118f2b757..49bb95f32d517 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../../ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../../ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
index 48cc4f7aa985d..a48d929a86067 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../../../test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"","sources":["../../../test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AAC9B,2DAA8D;AACnD,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFY,gBAAE;AAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC;AACd,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index 476d3d9396665..b9e5ddb335f92 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../../outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"","sources":["../../../../outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
index 5132061665307..d9151baabe48c 100644
--- a/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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diff --git a/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/amd/m1.js.map b/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/amd/m1.js.map
index 41a7fb93ee628..dcdf5faf89716 100644
--- a/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/amd/m1.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/amd/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/amd/test.js.map b/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/amd/test.js.map
index 0deeb01864d89..9a899efce6487 100644
--- a/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/node/m1.js.map b/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/node/m1.js.map
index 6af45080bd6c1..87fa414a454ee 100644
--- a/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/node/m1.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/node/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/node/test.js.map b/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/node/test.js.map
index 40fdb33821b7c..57b2f0a9935b7 100644
--- a/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSimpleNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map b/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
index 761471d9d8204..128c9957bf43b 100644
--- a/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index d3fedc589bffa..50263c64897cd 100644
--- a/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map b/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
index 2923aa0a0140a..40d0111893e18 100644
--- a/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
index 8cd970cb557aa..cc2b2e9b918e4 100644
--- a/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
index 105ebefb06ec7..a910ecda80eb3 100644
--- a/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/amd/ref/m1.js.map
index 41a7fb93ee628..dcdf5faf89716 100644
--- a/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/amd/test.js.map
index 0deeb01864d89..9a899efce6487 100644
--- a/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/node/ref/m1.js.map
index 6af45080bd6c1..87fa414a454ee 100644
--- a/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/node/test.js.map
index 92ae347312c14..6f71fb82f4c2d 100644
--- a/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSubfolderNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
index 8e4c69b85cad6..28136d8ffc30a 100644
--- a/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index d3fedc589bffa..50263c64897cd 100644
--- a/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../../test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
index f102ba902d9de..f5f5dfcd793b1 100644
--- a/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"","sources":["../../../ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
index be65d1d02a5d2..9c9d3ffec9263 100644
--- a/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"","sources":["../../test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AACnB,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
index 12c15dd7143ae..a3532b9e4ce85 100644
--- a/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourcemapModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlMixedSubfolderNoOutdir/amd/ref/m2.js.map b/tests/baselines/reference/project/sourcerootUrlMixedSubfolderNoOutdir/amd/ref/m2.js.map
index e68a248d5d7dc..a1c9985be48e4 100644
--- a/tests/baselines/reference/project/sourcerootUrlMixedSubfolderNoOutdir/amd/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlMixedSubfolderNoOutdir/amd/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlMixedSubfolderNoOutdir/node/ref/m2.js.map b/tests/baselines/reference/project/sourcerootUrlMixedSubfolderNoOutdir/node/ref/m2.js.map
index c6ff2cc27ce1e..9ccd44f3a018a 100644
--- a/tests/baselines/reference/project/sourcerootUrlMixedSubfolderNoOutdir/node/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlMixedSubfolderNoOutdir/node/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
index e68a248d5d7dc..a1c9985be48e4 100644
--- a/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map b/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
index c6ff2cc27ce1e..9ccd44f3a018a 100644
--- a/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m2.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m2.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
index 35e555688e090..26353fdf396cc 100644
--- a/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m1.ts","ref/m2.ts","test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m1.ts","ref/m2.ts","test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map b/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
index 19bcc3ee32a40..ec57587014d89 100644
--- a/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlMixedSubfolderSpecifyOutputFileAndOutputDirectory/amd/bin/outAndOutDirFile.js.map
@@ -1 +1 @@
-{"version":3,"file":"outAndOutDirFile.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m1.ts","ref/m2.ts","test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
+{"version":3,"file":"outAndOutDirFile.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m1.ts","ref/m2.ts","test.ts"],"names":[],"mappings":"AAAA,IAAI,KAAK,GAAG,EAAE,CAAC;AACf;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AAC/B;IACI,MAAM,CAAC,YAAY,CAAC;AACxB,CAAC;;;ICRU,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;ACRD,iCAAiC;AACjC,iCAAiC;AACjC,IAAI,EAAE,GAAG,EAAE,CAAC;AACZ;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAED,IAAI,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AACzB;IACI,MAAM,CAAC,SAAS,CAAC;AACrB,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/amd/diskFile0.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/amd/diskFile0.js.map
index a8c35bc15c620..59ebd34cfe355 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/amd/diskFile0.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/amd/diskFile0.js.map
@@ -1 +1 @@
-{"version":3,"file":"m2.js","sourceRoot":"http://typescript.codeplex.com/","sources":["outputdir_module_multifolder_ref/m2.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/amd/ref/m1.js.map
index f1623c531a61c..9afdf343f77e1 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/amd/test.js.map
index b199c0dc1adfd..5000f3a49b9f2 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/node/diskFile0.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/node/diskFile0.js.map
index ef338fcc8875e..866e1007e240c 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/node/diskFile0.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/node/diskFile0.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/node/ref/m1.js.map
index 10777c25bd48c..0f5e28ddbf724 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/node/test.js.map
index dbab2cdf457a2..a39cd29ba7764 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderNoOutdir/node/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index f1623c531a61c..9afdf343f77e1 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
index b199c0dc1adfd..5000f3a49b9f2 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index a8c35bc15c620..59ebd34cfe355 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/amd/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
index 10777c25bd48c..0f5e28ddbf724 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"http://typescript.codeplex.com/","sources":["outputdir_module_multifolder/ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
index dbab2cdf457a2..a39cd29ba7764 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
index ef338fcc8875e..866e1007e240c 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputDirectory/node/outdir/simple/outputdir_module_multifolder_ref/m2.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
index 5a120cbe80072..c4facdba9364e 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleMultifolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/amd/m1.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/amd/m1.js.map
index 26e7b01ccdba5..1706ba768171b 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/amd/m1.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/amd/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/amd/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/amd/test.js.map
index f92c491640f17..07e9825a93a7a 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/node/m1.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/node/m1.js.map
index 1b563cf259d6d..d134ab774afff 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/node/m1.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/node/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/node/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/node/test.js.map
index 46e8000caa09c..d07c1aa067898 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSimpleNoOutdir/node/test.js.map
@@ -1 +1 @@
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diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
index 26e7b01ccdba5..1706ba768171b 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index f92c491640f17..07e9825a93a7a 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
index 1b563cf259d6d..d134ab774afff 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
index 46e8000caa09c..d07c1aa067898 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
index 28d5511a5ee6f..64c90d05e8808 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSimpleSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/amd/ref/m1.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/amd/ref/m1.js.map
index 88ce97eeeffa7..7e2762b41a45b 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/amd/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/amd/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/amd/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/amd/test.js.map
index f92c491640f17..07e9825a93a7a 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/amd/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/amd/test.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/node/ref/m1.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/node/ref/m1.js.map
index e28d378dfc002..eb8832755683f 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/node/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/node/ref/m1.js.map
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/node/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/node/test.js.map
index c956b034f6f9d..4f024886c03bb 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/node/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderNoOutdir/node/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AACnB,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AACnB,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFY,gBAAE;AAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
index 88ce97eeeffa7..7e2762b41a45b 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m1.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
index f92c491640f17..07e9825a93a7a 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/amd/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["test.ts"],"names":[],"mappings":";;IACW,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFY,gBAAE;IAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
index e28d378dfc002..eb8832755683f 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/ref/m1.js.map
@@ -1 +1 @@
-{"version":3,"file":"m1.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFD,sBAEC;AAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
+{"version":3,"file":"m1.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m1.ts"],"names":[],"mappings":";AAAW,QAAA,KAAK,GAAG,EAAE,CAAC;AACtB;IAAA;IAEA,CAAC;IAAD,YAAC;AAAD,CAAC,AAFD,IAEC;AAFY,sBAAK;AAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;AACtC;IACI,MAAM,CAAC,oBAAY,CAAC;AACxB,CAAC;AAFD,sBAEC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
index c956b034f6f9d..4f024886c03bb 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputDirectory/node/outdir/simple/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AACnB,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFD,gBAEC;AAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["test.ts"],"names":[],"mappings":";AAAA,2BAA8B;AACnB,QAAA,EAAE,GAAG,EAAE,CAAC;AACnB;IAAA;IAEA,CAAC;IAAD,SAAC;AAAD,CAAC,AAFD,IAEC;AAFY,gBAAE;AAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;AAChC;IACI,MAAM,CAAC,iBAAS,CAAC;AACrB,CAAC;AAFD,gBAEC;AAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
index a46d68e9b0541..6d26d850e1924 100644
--- a/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
+++ b/tests/baselines/reference/project/sourcerootUrlModuleSubfolderSpecifyOutputFile/amd/bin/test.js.map
@@ -1 +1 @@
-{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m1.ts","test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFD,sBAEC;IAEU,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICPU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFD,gBAEC;IAEU,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
+{"version":3,"file":"test.js","sourceRoot":"http://typescript.codeplex.com/","sources":["ref/m1.ts","test.ts"],"names":[],"mappings":";;IAAW,QAAA,KAAK,GAAG,EAAE,CAAC;IACtB;QAAA;QAEA,CAAC;QAAD,YAAC;IAAD,CAAC,AAFD,IAEC;IAFY,sBAAK;IAIP,QAAA,YAAY,GAAG,IAAI,KAAK,EAAE,CAAC;IACtC;QACI,MAAM,CAAC,oBAAY,CAAC;IACxB,CAAC;IAFD,sBAEC;;;;ICPU,QAAA,EAAE,GAAG,EAAE,CAAC;IACnB;QAAA;QAEA,CAAC;QAAD,SAAC;IAAD,CAAC,AAFD,IAEC;IAFY,gBAAE;IAIJ,QAAA,SAAS,GAAG,IAAI,EAAE,EAAE,CAAC;IAChC;QACI,MAAM,CAAC,iBAAS,CAAC;IACrB,CAAC;IAFD,gBAEC;IAEU,QAAA,EAAE,GAAG,EAAE,CAAC,KAAK,CAAC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/sourceMapValidationDecorators.js.map b/tests/baselines/reference/sourceMapValidationDecorators.js.map
index 535d6603d8c02..ac635a518f157 100644
--- a/tests/baselines/reference/sourceMapValidationDecorators.js.map
+++ b/tests/baselines/reference/sourceMapValidationDecorators.js.map
@@ -1,2 +1,2 @@
 //// [sourceMapValidationDecorators.js.map]
-{"version":3,"file":"sourceMapValidationDecorators.js","sourceRoot":"","sources":["sourceMapValidationDecorators.ts"],"names":[],"mappings":";;;;;;;;;AASA;IACI,iBAGS,QAAgB;QAIvB,WAAc;aAAd,UAAc,EAAd,qBAAc,EAAd,IAAc;YAAd,0BAAc;;QAJP,aAAQ,GAAR,QAAQ,CAAQ;IAKzB,CAAC;IAID,uBAAK,GAAL;QACI,MAAM,CAAC,MAAM,GAAG,IAAI,CAAC,QAAQ,GAAG,OAAO,CAAC;IAC5C,CAAC;IAUO,oBAAE,GAAV,UAGE,CAAS;QACP,MAAM,CAAC,IAAI,CAAC,QAAQ,CAAC;IACzB,CAAC;IAID,sBAAI,8BAAS;aAAb;YACI,MAAM,CAAC,IAAI,CAAC,QAAQ,CAAC;QACzB,CAAC;aAED,UAGE,SAAiB;YACf,IAAI,CAAC,QAAQ,GAAG,SAAS,CAAC;QAC9B,CAAC;;;OAPA;IAQL,cAAC;AAAD,CAAC,AA5CD,IA4CC;AArBkB,UAAE,GAAW,EAAE,CAAC;AAV/B;IAFC,kBAAkB;IAClB,kBAAkB,CAAC,EAAE,CAAC;oCAGtB;AAID;IAFC,kBAAkB;IAClB,kBAAkB,CAAC,EAAE,CAAC;kCACL;AAMlB;IACG,WAAA,mBAAmB,CAAA;IACnB,WAAA,mBAAmB,CAAC,EAAE,CAAC,CAAA;iCAGzB;AAID;IAFC,kBAAkB;IAClB,kBAAkB,CAAC,EAAE,CAAC;IAMpB,WAAA,mBAAmB,CAAA;IACnB,WAAA,mBAAmB,CAAC,EAAE,CAAC,CAAA;wCAJzB;AAbD;IAFC,kBAAkB;IAClB,kBAAkB,CAAC,EAAE,CAAC;yBACQ;AAvBnC;IAFC,eAAe;IACf,eAAe,CAAC,EAAE,CAAC;IAGb,WAAA,mBAAmB,CAAA;IACnB,WAAA,mBAAmB,CAAC,EAAE,CAAC,CAAA;IAGvB,WAAA,mBAAmB,CAAA;IACnB,WAAA,mBAAmB,CAAC,EAAE,CAAC,CAAA;WAqC7B"}
\ No newline at end of file
+{"version":3,"file":"sourceMapValidationDecorators.js","sourceRoot":"","sources":["sourceMapValidationDecorators.ts"],"names":[],"mappings":";;;;;;;;;AASA,IAAM,OAAO;IACT,iBAGS,QAAgB;QAIvB,WAAc;aAAd,UAAc,EAAd,qBAAc,EAAd,IAAc;YAAd,0BAAc;;QAJP,aAAQ,GAAR,QAAQ,CAAQ;IAKzB,CAAC;IAID,uBAAK,GAAL;QACI,MAAM,CAAC,MAAM,GAAG,IAAI,CAAC,QAAQ,GAAG,OAAO,CAAC;IAC5C,CAAC;IAUO,oBAAE,GAAV,UAGE,CAAS;QACP,MAAM,CAAC,IAAI,CAAC,QAAQ,CAAC;IACzB,CAAC;IAID,sBAAI,8BAAS;aAAb;YACI,MAAM,CAAC,IAAI,CAAC,QAAQ,CAAC;QACzB,CAAC;aAED,UAGE,SAAiB;YACf,IAAI,CAAC,QAAQ,GAAG,SAAS,CAAC;QAC9B,CAAC;;;OAPA;IAQL,cAAC;AAAD,CAAC,AA5CD,IA4CC;AArBkB,UAAE,GAAW,EAAE,CAAC;AAV/B;IAFC,kBAAkB;IAClB,kBAAkB,CAAC,EAAE,CAAC;oCAGtB;AAID;IAFC,kBAAkB;IAClB,kBAAkB,CAAC,EAAE,CAAC;kCACL;AAMlB;IACG,WAAA,mBAAmB,CAAA;IACnB,WAAA,mBAAmB,CAAC,EAAE,CAAC,CAAA;iCAGzB;AAID;IAFC,kBAAkB;IAClB,kBAAkB,CAAC,EAAE,CAAC;IAMpB,WAAA,mBAAmB,CAAA;IACnB,WAAA,mBAAmB,CAAC,EAAE,CAAC,CAAA;wCAJzB;AAbD;IAFC,kBAAkB;IAClB,kBAAkB,CAAC,EAAE,CAAC;yBACQ;AAvB7B,OAAO;IAFZ,eAAe;IACf,eAAe,CAAC,EAAE,CAAC;IAGb,WAAA,mBAAmB,CAAA;IACnB,WAAA,mBAAmB,CAAC,EAAE,CAAC,CAAA;IAGvB,WAAA,mBAAmB,CAAA;IACnB,WAAA,mBAAmB,CAAC,EAAE,CAAC,CAAA;GAPxB,OAAO,CA4CZ"}
\ No newline at end of file
diff --git a/tests/baselines/reference/sourceMapValidationDecorators.sourcemap.txt b/tests/baselines/reference/sourceMapValidationDecorators.sourcemap.txt
index 37f6a4bea0805..d581fdef88634 100644
--- a/tests/baselines/reference/sourceMapValidationDecorators.sourcemap.txt
+++ b/tests/baselines/reference/sourceMapValidationDecorators.sourcemap.txt
@@ -19,7 +19,9 @@ sourceFile:sourceMapValidationDecorators.ts
 >>>};
 >>>var Greeter = (function () {
 1 >
-2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+2 >^^^^
+3 >    ^^^^^^^
+4 >           ^^^^^^^^^^^^^^^^^^^^^^->
 1 >declare function ClassDecorator1(target: Function): void;
   >declare function ClassDecorator2(x: number): (target: Function) => void;
   >declare function PropertyDecorator1(target: Object, key: string | symbol, descriptor?: PropertyDescriptor): void;
@@ -30,13 +32,17 @@ sourceFile:sourceMapValidationDecorators.ts
   >@ClassDecorator1
   >@ClassDecorator2(10)
   >
+2 >class 
+3 >    Greeter
 1 >Emitted(10, 1) Source(10, 1) + SourceIndex(0)
+2 >Emitted(10, 5) Source(10, 7) + SourceIndex(0)
+3 >Emitted(10, 12) Source(10, 14) + SourceIndex(0)
 ---
 >>>    function Greeter(greeting) {
 1->^^^^
 2 >    ^^^^^^^^^^^^^^^^^
 3 >                     ^^^^^^^^
-1->class Greeter {
+1-> {
   >    
 2 >    constructor(
   >          @ParameterDecorator1 
@@ -729,9 +735,12 @@ sourceFile:sourceMapValidationDecorators.ts
 ---
 >>>Greeter = __decorate([
 1 >
-2 >^^^^^^^^^^^^^^^^^^^^^->
+2 >^^^^^^^
+3 >       ^^^^^^^^^^^^^^->
 1 >
-1 >Emitted(59, 1) Source(10, 1) + SourceIndex(0)
+2 >Greeter
+1 >Emitted(59, 1) Source(10, 7) + SourceIndex(0)
+2 >Emitted(59, 8) Source(10, 14) + SourceIndex(0)
 ---
 >>>    ClassDecorator1,
 1->^^^^
@@ -846,46 +855,59 @@ sourceFile:sourceMapValidationDecorators.ts
 7 >Emitted(65, 40) Source(17, 31) + SourceIndex(0)
 ---
 >>>], Greeter);
-1 >^^^^^^^^^^^
-2 >           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
-1 > 
-  >      ...b: string[]) {
-  >    }
-  >    
-  >    @PropertyDecorator1
-  >    @PropertyDecorator2(40)
-  >    greet() {
-  >        return "<h1>" + this.greeting + "</h1>";
-  >    }
-  >
-  >    @PropertyDecorator1
-  >    @PropertyDecorator2(50)
-  >    private x: string;
-  >
-  >    @PropertyDecorator1
-  >    @PropertyDecorator2(60)
-  >    private static x1: number = 10;
-  >    
-  >    private fn(
-  >      @ParameterDecorator1 
-  >      @ParameterDecorator2(70) 
-  >      x: number) {
-  >        return this.greeting;
-  >    }
-  >
-  >    @PropertyDecorator1
-  >    @PropertyDecorator2(80)
-  >    get greetings() {
-  >        return this.greeting;
-  >    }
-  >
-  >    set greetings(
-  >      @ParameterDecorator1 
-  >      @ParameterDecorator2(90) 
-  >      greetings: string) {
-  >        this.greeting = greetings;
-  >    }    
-  >}
-1 >Emitted(66, 12) Source(54, 2) + SourceIndex(0)
+1 >^^^
+2 >   ^^^^^^^
+3 >          ^
+4 >           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+2 >   Greeter
+3 >           {
+  >              constructor(
+  >                @ParameterDecorator1 
+  >                @ParameterDecorator2(20) 
+  >                public greeting: string, 
+  >                
+  >                @ParameterDecorator1 
+  >                @ParameterDecorator2(30) 
+  >                ...b: string[]) {
+  >              }
+  >              
+  >              @PropertyDecorator1
+  >              @PropertyDecorator2(40)
+  >              greet() {
+  >                  return "<h1>" + this.greeting + "</h1>";
+  >              }
+  >          
+  >              @PropertyDecorator1
+  >              @PropertyDecorator2(50)
+  >              private x: string;
+  >          
+  >              @PropertyDecorator1
+  >              @PropertyDecorator2(60)
+  >              private static x1: number = 10;
+  >              
+  >              private fn(
+  >                @ParameterDecorator1 
+  >                @ParameterDecorator2(70) 
+  >                x: number) {
+  >                  return this.greeting;
+  >              }
+  >          
+  >              @PropertyDecorator1
+  >              @PropertyDecorator2(80)
+  >              get greetings() {
+  >                  return this.greeting;
+  >              }
+  >          
+  >              set greetings(
+  >                @ParameterDecorator1 
+  >                @ParameterDecorator2(90) 
+  >                greetings: string) {
+  >                  this.greeting = greetings;
+  >              }    
+  >          }
+1 >Emitted(66, 4) Source(10, 7) + SourceIndex(0)
+2 >Emitted(66, 11) Source(10, 14) + SourceIndex(0)
+3 >Emitted(66, 12) Source(54, 2) + SourceIndex(0)
 ---
 >>>//# sourceMappingURL=sourceMapValidationDecorators.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/systemModule7.js b/tests/baselines/reference/systemModule7.js
index bf34e3f786ccb..d25ca627e441b 100644
--- a/tests/baselines/reference/systemModule7.js
+++ b/tests/baselines/reference/systemModule7.js
@@ -21,7 +21,7 @@ System.register([], function (exports_1, context_1) {
             // filename: instantiatedModule.ts
             (function (M) {
                 var x = 1;
-            })(M = M || (M = {}));
+            })(M || (M = {}));
             exports_1("M", M);
         }
     };
diff --git a/tests/baselines/reference/systemModuleDeclarationMerging.js b/tests/baselines/reference/systemModuleDeclarationMerging.js
index 88b1b20149512..27cdd9f157274 100644
--- a/tests/baselines/reference/systemModuleDeclarationMerging.js
+++ b/tests/baselines/reference/systemModuleDeclarationMerging.js
@@ -21,7 +21,7 @@ System.register([], function (exports_1, context_1) {
         execute: function () {
             (function (F) {
                 var x;
-            })(F = F || (F = {}));
+            })(F || (F = {}));
             exports_1("F", F);
             C = (function () {
                 function C() {
@@ -31,14 +31,14 @@ System.register([], function (exports_1, context_1) {
             exports_1("C", C);
             (function (C) {
                 var x;
-            })(C = C || (C = {}));
+            })(C || (C = {}));
             exports_1("C", C);
             (function (E) {
-            })(E = E || (E = {}));
+            })(E || (E = {}));
             exports_1("E", E);
             (function (E) {
                 var x;
-            })(E = E || (E = {}));
+            })(E || (E = {}));
             exports_1("E", E);
         }
     };
diff --git a/tests/baselines/reference/systemModuleNonTopLevelModuleMembers.js b/tests/baselines/reference/systemModuleNonTopLevelModuleMembers.js
index db907c49d911b..c6d3c8295e01f 100644
--- a/tests/baselines/reference/systemModuleNonTopLevelModuleMembers.js
+++ b/tests/baselines/reference/systemModuleNonTopLevelModuleMembers.js
@@ -30,11 +30,11 @@ System.register([], function (exports_1, context_1) {
             exports_1("TopLevelClass", TopLevelClass);
             (function (TopLevelModule) {
                 var v;
-            })(TopLevelModule = TopLevelModule || (TopLevelModule = {}));
+            })(TopLevelModule || (TopLevelModule = {}));
             exports_1("TopLevelModule", TopLevelModule);
             (function (TopLevelEnum) {
                 TopLevelEnum[TopLevelEnum["E"] = 0] = "E";
-            })(TopLevelEnum = TopLevelEnum || (TopLevelEnum = {}));
+            })(TopLevelEnum || (TopLevelEnum = {}));
             exports_1("TopLevelEnum", TopLevelEnum);
             (function (TopLevelModule2) {
                 var NonTopLevelClass = (function () {
@@ -53,7 +53,7 @@ System.register([], function (exports_1, context_1) {
                 (function (NonTopLevelEnum) {
                     NonTopLevelEnum[NonTopLevelEnum["E"] = 0] = "E";
                 })(NonTopLevelEnum = TopLevelModule2.NonTopLevelEnum || (TopLevelModule2.NonTopLevelEnum = {}));
-            })(TopLevelModule2 = TopLevelModule2 || (TopLevelModule2 = {}));
+            })(TopLevelModule2 || (TopLevelModule2 = {}));
             exports_1("TopLevelModule2", TopLevelModule2);
         }
     };
diff --git a/tests/baselines/reference/tsxDefaultImports.js b/tests/baselines/reference/tsxDefaultImports.js
index e7e0a13860d83..46a94dea92fcf 100644
--- a/tests/baselines/reference/tsxDefaultImports.js
+++ b/tests/baselines/reference/tsxDefaultImports.js
@@ -25,9 +25,9 @@ var SomeClass = (function () {
     }
     return SomeClass;
 }());
+SomeClass.E = SomeEnum;
 exports.__esModule = true;
 exports["default"] = SomeClass;
-SomeClass.E = SomeEnum;
 //// [b.js]
 "use strict";
 var a_1 = require("./a");

From 76d194440c2586557b73bb15cb40dd9550ff3a0b Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 20 Oct 2016 09:06:36 -0700
Subject: [PATCH 063/224] Spread no longer distributes intersections

---
 src/compiler/checker.ts | 18 ++++--------------
 src/compiler/types.ts   |  2 +-
 2 files changed, 5 insertions(+), 15 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index e3651f6cf3014..f0ad77cd5c471 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5810,11 +5810,6 @@ namespace ts {
                 types.push(rspread.right);
                 return getSpreadType(types, symbol, aliasSymbol, aliasTypeArguments);
             }
-            if (right.flags & TypeFlags.Intersection) {
-                const spreads = map((right as IntersectionType).types,
-                                    t => getSpreadType(types.slice().concat([t]), symbol, aliasSymbol, aliasTypeArguments));
-                return getIntersectionType(spreads, aliasSymbol, aliasTypeArguments);
-            }
             if (right.flags & TypeFlags.Union) {
                 const spreads = map((right as UnionType).types,
                                     t => getSpreadType(types.slice().concat([t]), symbol, aliasSymbol, aliasTypeArguments));
@@ -5840,11 +5835,6 @@ namespace ts {
                 const simplified = getSpreadType([right, (left as SpreadType).right], symbol, aliasSymbol, aliasTypeArguments);
                 return getSpreadType([(left as SpreadType).left, simplified], symbol, aliasSymbol, aliasTypeArguments);
             }
-            if (left.flags & TypeFlags.Intersection) {
-                const spreads = map((left as IntersectionType).types,
-                                  t => getSpreadType(types.slice().concat([t, right]), symbol, aliasSymbol, aliasTypeArguments));
-                return getIntersectionType(spreads, aliasSymbol, aliasTypeArguments);
-            }
             if (left.flags & TypeFlags.Union) {
                 const spreads = map((left as UnionType).types,
                                   t => getSpreadType(types.slice().concat([t, right]), symbol, aliasSymbol, aliasTypeArguments));
@@ -5901,9 +5891,9 @@ namespace ts {
             }
             const spread = spreadTypes[id] = createObjectType(TypeFlags.Spread, symbol) as SpreadType;
             Debug.assert(!!(left.flags & (TypeFlags.Spread | TypeFlags.ObjectType)), "Left flags: " + left.flags.toString(2));
-            Debug.assert(!!(right.flags & (TypeFlags.TypeParameter | TypeFlags.ObjectType)), "Right flags: " + right.flags.toString(2));
+            Debug.assert(!!(right.flags & (TypeFlags.TypeParameter | TypeFlags.Intersection | TypeFlags.ObjectType)), "Right flags: " + right.flags.toString(2));
             spread.left = left as SpreadType | ResolvedType;
-            spread.right = right as TypeParameter | ResolvedType;
+            spread.right = right as TypeParameter | IntersectionType | ResolvedType;
             spread.aliasSymbol = aliasSymbol;
             spread.aliasTypeArguments = aliasTypeArguments;
             return spread;
@@ -6953,11 +6943,11 @@ namespace ts {
                         spreadTypeRelatedTo(source.right.flags & TypeFlags.ObjectType ? source.left as SpreadType : source,
                                             target.right.flags & TypeFlags.ObjectType ? target.left as SpreadType : target);
                 }
-                // If both right sides are type parameters, then they must be identical for the spread types to be related.
+                // If both right sides are type parameters or intersections, then they must be identical for the spread types to be related.
                 // It also means that the left sides are either spread types or object types.
 
                 // if one left is object and the other is spread, that means the second has another type parameter. which isn't allowed
-                if (target.right.symbol !== source.right.symbol) {
+                if (target.right !== source.right) {
                     return false;
                 }
                 if (source.left.flags & TypeFlags.Spread && target.left.flags & TypeFlags.Spread) {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 10c9abbd1ca21..3dbfba72acbd0 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2780,7 +2780,7 @@ namespace ts {
     /* @internal */
     export interface SpreadType extends Type {
         left: SpreadType | ResolvedType;
-        right: TypeParameter | ResolvedType;
+        right: TypeParameter | IntersectionType | ResolvedType;
     }
 
     /* @internal */

From d9afa34be18a2ab55a321f605de78315fbb57143 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 20 Oct 2016 09:07:01 -0700
Subject: [PATCH 064/224] Update spread w/intersection tests

---
 .../reference/objectSpreadIntersection.js     |   8 -
 .../objectSpreadIntersection.symbols          | 232 +++++++-----------
 .../reference/objectSpreadIntersection.types  |  94 ++-----
 .../reference/objectSpreadNegative.errors.txt |  14 +-
 .../reference/objectSpreadNegative.js         |  14 +-
 .../types/spread/objectSpreadIntersection.ts  |   4 -
 .../types/spread/objectSpreadNegative.ts      |   7 +-
 7 files changed, 136 insertions(+), 237 deletions(-)

diff --git a/tests/baselines/reference/objectSpreadIntersection.js b/tests/baselines/reference/objectSpreadIntersection.js
index 0a7f1ddfcee43..d86b7bfca584c 100644
--- a/tests/baselines/reference/objectSpreadIntersection.js
+++ b/tests/baselines/reference/objectSpreadIntersection.js
@@ -3,7 +3,6 @@ function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tu: T | U;
     let uv: U & V;
     let result = { ...tu, ...uv, id: 'foo' };
-    let expected: ({ ...T, ...U, id: string } & { ...T, ...V, id: string }) | ({ ...U, id: string } & { ...U, ...V, id: string });
     let assignable: { ...(T | U), ...(U & V), id: string } = result;
 }
 // concrete types work
@@ -17,21 +16,18 @@ let assignable: { ...(A1 & A2) } = result;
 function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tuv: T & U & V;
     let result = { ...tuv, id: 'bar' };
-    let expected: { ...T, id: string } & { ...U, id: string } & { ...V, id: string } = result;
     let assignable: { ...(T & U & V), id: string } = result;
 }
 function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tu: T & U;
     let uv: U & V;
     let result = { ...tu, ...uv, id: 'baz' };
-    let expected: { ...T, ...U, id: string } & { ...T, ...V, id: string } & { ...U, id: string } & { ...U, ...V, id: string };
     let assignable: { ...(T & U), ...(U & V), id: string } = result;
 }
 function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
     let tu: T & U;
     let uv: U | V;
     let result = { ...tu, ...uv, id: 'qux' };
-    let expected: ({ ...T, ...U, id: string } & { ...U, id: string }) | ({ ...T, ...V, id: string } & { ...U, ...V, id: string });
     let assignable: { ...(T & U), ...(U | V), id: string } = result;
 }
 
@@ -50,7 +46,6 @@ function iteratedUnionIntersection(t, u, v) {
     var tu;
     var uv;
     var result = __assign({}, tu, uv, { id: 'foo' });
-    var expected;
     var assignable = result;
 }
 var a12;
@@ -60,20 +55,17 @@ var assignable = result;
 function tripleIntersection(t, u, v) {
     var tuv;
     var result = __assign({}, tuv, { id: 'bar' });
-    var expected = result;
     var assignable = result;
 }
 function iteratedDoubleIntersection(t, u, v) {
     var tu;
     var uv;
     var result = __assign({}, tu, uv, { id: 'baz' });
-    var expected;
     var assignable = result;
 }
 function iteratedIntersectionUnion(t, u, v) {
     var tu;
     var uv;
     var result = __assign({}, tu, uv, { id: 'qux' });
-    var expected;
     var assignable = result;
 }
diff --git a/tests/baselines/reference/objectSpreadIntersection.symbols b/tests/baselines/reference/objectSpreadIntersection.symbols
index c59c37670b25d..6dd27645ddf13 100644
--- a/tests/baselines/reference/objectSpreadIntersection.symbols
+++ b/tests/baselines/reference/objectSpreadIntersection.symbols
@@ -25,195 +25,143 @@ function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
 >result : Symbol(result, Decl(objectSpreadIntersection.ts, 3, 7))
 >id : Symbol(id, Decl(objectSpreadIntersection.ts, 3, 32))
 
-    let expected: ({ ...T, ...U, id: string } & { ...T, ...V, id: string }) | ({ ...U, id: string } & { ...U, ...V, id: string });
->expected : Symbol(expected, Decl(objectSpreadIntersection.ts, 4, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 32))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 61))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 86))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 115))
-
     let assignable: { ...(T | U), ...(U & V), id: string } = result;
->assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 5, 7))
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 4, 7))
 >T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
 >U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
 >V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 5, 45))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 45))
 >result : Symbol(result, Decl(objectSpreadIntersection.ts, 3, 7))
 }
 // concrete types work
 interface A1 { a: number }
->A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 6, 1))
->a : Symbol(A1.a, Decl(objectSpreadIntersection.ts, 8, 14))
+>A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 5, 1))
+>a : Symbol(A1.a, Decl(objectSpreadIntersection.ts, 7, 14))
 
 interface A2 { a: string }
->A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 8, 26))
->a : Symbol(A2.a, Decl(objectSpreadIntersection.ts, 9, 14))
+>A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 7, 26))
+>a : Symbol(A2.a, Decl(objectSpreadIntersection.ts, 8, 14))
 
 let a12: A1 & A2;
->a12 : Symbol(a12, Decl(objectSpreadIntersection.ts, 10, 3))
->A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 6, 1))
->A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 8, 26))
+>a12 : Symbol(a12, Decl(objectSpreadIntersection.ts, 9, 3))
+>A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 5, 1))
+>A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 7, 26))
 
 let result = { ...a12 };
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 11, 3))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 10, 3))
 
 let sn: number & string = result.a;
->sn : Symbol(sn, Decl(objectSpreadIntersection.ts, 12, 3))
->result.a : Symbol(a, Decl(objectSpreadIntersection.ts, 8, 14), Decl(objectSpreadIntersection.ts, 9, 14))
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 11, 3))
->a : Symbol(a, Decl(objectSpreadIntersection.ts, 8, 14), Decl(objectSpreadIntersection.ts, 9, 14))
+>sn : Symbol(sn, Decl(objectSpreadIntersection.ts, 11, 3))
+>result.a : Symbol(a, Decl(objectSpreadIntersection.ts, 7, 14), Decl(objectSpreadIntersection.ts, 8, 14))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 10, 3))
+>a : Symbol(a, Decl(objectSpreadIntersection.ts, 7, 14), Decl(objectSpreadIntersection.ts, 8, 14))
 
 let assignable: { ...(A1 & A2) } = result;
->assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 13, 3))
->A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 6, 1))
->A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 8, 26))
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 11, 3))
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 12, 3))
+>A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 5, 1))
+>A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 7, 26))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 10, 3))
 
 function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
->tripleIntersection : Symbol(tripleIntersection, Decl(objectSpreadIntersection.ts, 13, 42))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 15, 28))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
->t : Symbol(t, Decl(objectSpreadIntersection.ts, 15, 37))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 15, 28))
->u : Symbol(u, Decl(objectSpreadIntersection.ts, 15, 42))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
->v : Symbol(v, Decl(objectSpreadIntersection.ts, 15, 48))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
+>tripleIntersection : Symbol(tripleIntersection, Decl(objectSpreadIntersection.ts, 12, 42))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 14, 28))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 14, 30))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 14, 33))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 14, 37))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 14, 28))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 14, 42))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 14, 30))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 14, 48))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 14, 33))
 
     let tuv: T & U & V;
->tuv : Symbol(tuv, Decl(objectSpreadIntersection.ts, 16, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 15, 28))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
+>tuv : Symbol(tuv, Decl(objectSpreadIntersection.ts, 15, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 14, 28))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 14, 30))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 14, 33))
 
     let result = { ...tuv, id: 'bar' };
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 17, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 17, 26))
-
-    let expected: { ...T, id: string } & { ...U, id: string } & { ...V, id: string } = result;
->expected : Symbol(expected, Decl(objectSpreadIntersection.ts, 18, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 15, 28))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 18, 25))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 18, 48))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 18, 71))
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 17, 7))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 16, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 16, 26))
 
     let assignable: { ...(T & U & V), id: string } = result;
->assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 19, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 15, 28))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 15, 30))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 15, 33))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 19, 37))
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 17, 7))
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 17, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 14, 28))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 14, 30))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 14, 33))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 17, 37))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 16, 7))
 }
 function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
->iteratedDoubleIntersection : Symbol(iteratedDoubleIntersection, Decl(objectSpreadIntersection.ts, 20, 1))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
->t : Symbol(t, Decl(objectSpreadIntersection.ts, 21, 45))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
->u : Symbol(u, Decl(objectSpreadIntersection.ts, 21, 50))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
->v : Symbol(v, Decl(objectSpreadIntersection.ts, 21, 56))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
+>iteratedDoubleIntersection : Symbol(iteratedDoubleIntersection, Decl(objectSpreadIntersection.ts, 18, 1))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 19, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 19, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 19, 41))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 19, 45))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 19, 36))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 19, 50))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 19, 38))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 19, 56))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 19, 41))
 
     let tu: T & U;
->tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 22, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
+>tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 20, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 19, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 19, 38))
 
     let uv: U & V;
->uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 23, 7))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
+>uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 21, 7))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 19, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 19, 41))
 
     let result = { ...tu, ...uv, id: 'baz' };
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 24, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 24, 32))
-
-    let expected: { ...T, ...U, id: string } & { ...T, ...V, id: string } & { ...U, id: string } & { ...U, ...V, id: string };
->expected : Symbol(expected, Decl(objectSpreadIntersection.ts, 25, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 31))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 60))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 83))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 25, 112))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 22, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 22, 32))
 
     let assignable: { ...(T & U), ...(U & V), id: string } = result;
->assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 26, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 21, 36))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 21, 38))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 21, 41))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 26, 45))
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 24, 7))
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 23, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 19, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 19, 38))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 19, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 19, 41))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 23, 45))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 22, 7))
 }
 function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
->iteratedIntersectionUnion : Symbol(iteratedIntersectionUnion, Decl(objectSpreadIntersection.ts, 27, 1))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
->t : Symbol(t, Decl(objectSpreadIntersection.ts, 28, 44))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
->u : Symbol(u, Decl(objectSpreadIntersection.ts, 28, 49))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
->v : Symbol(v, Decl(objectSpreadIntersection.ts, 28, 55))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
+>iteratedIntersectionUnion : Symbol(iteratedIntersectionUnion, Decl(objectSpreadIntersection.ts, 24, 1))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 25, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 25, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 25, 40))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 25, 44))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 25, 35))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 25, 49))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 25, 37))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 25, 55))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 25, 40))
 
     let tu: T & U;
->tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 29, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
+>tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 26, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 25, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 25, 37))
 
     let uv: U | V;
->uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 30, 7))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
+>uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 27, 7))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 25, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 25, 40))
 
     let result = { ...tu, ...uv, id: 'qux' };
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 31, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 31, 32))
-
-    let expected: ({ ...T, ...U, id: string } & { ...U, id: string }) | ({ ...T, ...V, id: string } & { ...U, ...V, id: string });
->expected : Symbol(expected, Decl(objectSpreadIntersection.ts, 32, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 32))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 55))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 86))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 115))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 28, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 28, 32))
 
     let assignable: { ...(T & U), ...(U | V), id: string } = result;
->assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 33, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 28, 35))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 28, 37))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 28, 40))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 33, 45))
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 31, 7))
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 29, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 25, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 25, 37))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 25, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 25, 40))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 29, 45))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 28, 7))
 }
 
 
diff --git a/tests/baselines/reference/objectSpreadIntersection.types b/tests/baselines/reference/objectSpreadIntersection.types
index 308200179166c..0e21f42a76bea 100644
--- a/tests/baselines/reference/objectSpreadIntersection.types
+++ b/tests/baselines/reference/objectSpreadIntersection.types
@@ -22,35 +22,21 @@ function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
 >V : V
 
     let result = { ...tu, ...uv, id: 'foo' };
->result : ({ ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...U; ...T; ...U; id: string; }) & ({ ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; } | { ...T; ...U; ...T; ...V; id: string; } | { ...U; ...T; ...U; ...V; id: string; })
->{ ...tu, ...uv, id: 'foo' } : ({ ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...U; ...T; ...U; id: string; }) & ({ ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; } | { ...T; ...U; ...T; ...V; id: string; } | { ...U; ...T; ...U; ...V; id: string; })
+>result : { ...T; ...U & V; id: string; } | { ...U; ...U & V; id: string; }
+>{ ...tu, ...uv, id: 'foo' } : { ...T; ...U & V; id: string; } | { ...U; ...U & V; id: string; }
 >tu : any
 >uv : any
 >id : string
 >'foo' : "foo"
 
-    let expected: ({ ...T, ...U, id: string } & { ...T, ...V, id: string }) | ({ ...U, id: string } & { ...U, ...V, id: string });
->expected : ({ ...T; ...U; id: string; } & { ...T; ...V; id: string; }) | ({ ...U; id: string; } & { ...U; ...V; id: string; })
->T : T
->U : U
->id : string
->T : T
->V : V
->id : string
->U : U
->id : string
->U : U
->V : V
->id : string
-
     let assignable: { ...(T | U), ...(U & V), id: string } = result;
->assignable : ({ ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...U; ...T; ...U; id: string; }) & ({ ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; } | { ...T; ...U; ...T; ...V; id: string; } | { ...U; ...T; ...U; ...V; id: string; })
+>assignable : { ...T; ...U & V; id: string; } | { ...U; ...U & V; id: string; }
 >T : T
 >U : U
 >U : U
 >V : V
 >id : string
->result : ({ ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...U; ...T; ...U; id: string; }) & ({ ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; } | { ...T; ...U; ...T; ...V; id: string; } | { ...U; ...T; ...U; ...V; id: string; })
+>result : { ...T; ...U & V; id: string; } | { ...U; ...U & V; id: string; }
 }
 // concrete types work
 interface A1 { a: number }
@@ -67,21 +53,21 @@ let a12: A1 & A2;
 >A2 : A2
 
 let result = { ...a12 };
->result : { a: number; } & { a: string; }
->{ ...a12 } : { a: number; } & { a: string; }
+>result : { ...A1 & A2 }
+>{ ...a12 } : { ...A1 & A2 }
 >a12 : any
 
 let sn: number & string = result.a;
 >sn : number & string
 >result.a : number & string
->result : { a: number; } & { a: string; }
+>result : { ...A1 & A2 }
 >a : number & string
 
 let assignable: { ...(A1 & A2) } = result;
->assignable : { a: number; } & { a: string; }
+>assignable : { ...A1 & A2 }
 >A1 : A1
 >A2 : A2
->result : { a: number; } & { a: string; }
+>result : { ...A1 & A2 }
 
 function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
 >tripleIntersection : <T, U, V>(t: T, u: U, v: V) => void
@@ -102,29 +88,19 @@ function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
 >V : V
 
     let result = { ...tuv, id: 'bar' };
->result : { ...T; id: string; } & { ...U; id: string; } & { ...V; id: string; }
->{ ...tuv, id: 'bar' } : { ...T; id: string; } & { ...U; id: string; } & { ...V; id: string; }
+>result : { ...T & U & V; id: string; }
+>{ ...tuv, id: 'bar' } : { ...T & U & V; id: string; }
 >tuv : any
 >id : string
 >'bar' : "bar"
 
-    let expected: { ...T, id: string } & { ...U, id: string } & { ...V, id: string } = result;
->expected : { ...T; id: string; } & { ...U; id: string; } & { ...V; id: string; }
->T : T
->id : string
->U : U
->id : string
->V : V
->id : string
->result : { ...T; id: string; } & { ...U; id: string; } & { ...V; id: string; }
-
     let assignable: { ...(T & U & V), id: string } = result;
->assignable : { ...T; id: string; } & { ...U; id: string; } & { ...V; id: string; }
+>assignable : { ...T & U & V; id: string; }
 >T : T
 >U : U
 >V : V
 >id : string
->result : { ...T; id: string; } & { ...U; id: string; } & { ...V; id: string; }
+>result : { ...T & U & V; id: string; }
 }
 function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
 >iteratedDoubleIntersection : <T, U, V>(t: T, u: U, v: V) => void
@@ -149,35 +125,21 @@ function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
 >V : V
 
     let result = { ...tu, ...uv, id: 'baz' };
->result : { ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...U; id: string; } & { ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; }
->{ ...tu, ...uv, id: 'baz' } : { ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...U; id: string; } & { ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; }
+>result : { ...T & U; ...U & V; id: string; }
+>{ ...tu, ...uv, id: 'baz' } : { ...T & U; ...U & V; id: string; }
 >tu : any
 >uv : any
 >id : string
 >'baz' : "baz"
 
-    let expected: { ...T, ...U, id: string } & { ...T, ...V, id: string } & { ...U, id: string } & { ...U, ...V, id: string };
->expected : { ...T; ...U; id: string; } & { ...T; ...V; id: string; } & { ...U; id: string; } & { ...U; ...V; id: string; }
->T : T
->U : U
->id : string
->T : T
->V : V
->id : string
->U : U
->id : string
->U : U
->V : V
->id : string
-
     let assignable: { ...(T & U), ...(U & V), id: string } = result;
->assignable : { ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...U; id: string; } & { ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; }
+>assignable : { ...T & U; ...U & V; id: string; }
 >T : T
 >U : U
 >U : U
 >V : V
 >id : string
->result : { ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...U; id: string; } & { ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; }
+>result : { ...T & U; ...U & V; id: string; }
 }
 function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
 >iteratedIntersectionUnion : <T, U, V>(t: T, u: U, v: V) => void
@@ -202,35 +164,21 @@ function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
 >V : V
 
     let result = { ...tu, ...uv, id: 'qux' };
->result : ({ ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...T; ...U; ...T; ...U; id: string; } & { ...U; id: string; }) | ({ ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; })
->{ ...tu, ...uv, id: 'qux' } : ({ ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...T; ...U; ...T; ...U; id: string; } & { ...U; id: string; }) | ({ ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; })
+>result : { ...T & U; ...T & U; ...U; id: string; } | { ...T & U; ...T & U; ...V; id: string; }
+>{ ...tu, ...uv, id: 'qux' } : { ...T & U; ...T & U; ...U; id: string; } | { ...T & U; ...T & U; ...V; id: string; }
 >tu : any
 >uv : any
 >id : string
 >'qux' : "qux"
 
-    let expected: ({ ...T, ...U, id: string } & { ...U, id: string }) | ({ ...T, ...V, id: string } & { ...U, ...V, id: string });
->expected : ({ ...T; ...U; id: string; } & { ...U; id: string; }) | ({ ...T; ...V; id: string; } & { ...U; ...V; id: string; })
->T : T
->U : U
->id : string
->U : U
->id : string
->T : T
->V : V
->id : string
->U : U
->V : V
->id : string
-
     let assignable: { ...(T & U), ...(U | V), id: string } = result;
->assignable : ({ ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...T; ...U; ...T; ...U; id: string; } & { ...U; id: string; }) | ({ ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; })
+>assignable : { ...T & U; ...T & U; ...U; id: string; } | { ...T & U; ...T & U; ...V; id: string; }
 >T : T
 >U : U
 >U : U
 >V : V
 >id : string
->result : ({ ...T; ...U; id: string; } & { ...U; ...T; ...U; id: string; } & { ...T; ...U; ...T; ...U; id: string; } & { ...U; id: string; }) | ({ ...T; ...V; id: string; } & { ...U; ...T; ...V; id: string; } & { ...T; ...U; ...T; ...V; id: string; } & { ...T; ...U; ...V; id: string; } & { ...U; ...T; ...U; ...V; id: string; } & { ...U; ...V; id: string; })
+>result : { ...T & U; ...T & U; ...U; id: string; } | { ...T & U; ...T & U; ...V; id: string; }
 }
 
 
diff --git a/tests/baselines/reference/objectSpreadNegative.errors.txt b/tests/baselines/reference/objectSpreadNegative.errors.txt
index b79354c4a9487..64928782280ae 100644
--- a/tests/baselines/reference/objectSpreadNegative.errors.txt
+++ b/tests/baselines/reference/objectSpreadNegative.errors.txt
@@ -18,10 +18,11 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(49,12): error TS233
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(55,9): error TS2339: Property 'm' does not exist on type '{ p: number; }'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(58,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ x: number; }' has no compatible call signatures.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(59,1): error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(63,12): error TS2322: Type '{ ...U }' is not assignable to type 'U'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(64,9): error TS2322: Type '{ ...T & V }' is not assignable to type '{ ...T & U }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(66,12): error TS2322: Type '{ ...U }' is not assignable to type 'U'.
 
 
-==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (18 errors) ====
+==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (19 errors) ====
     let o = { a: 1, b: 'no' }
     
     /// private propagates
@@ -119,8 +120,13 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(63,12): error TS232
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
     
-    // { ...U } is not assignable to U
-    function override<U>(initial: U, override: U): U {
+    function override<T,U,V>(initial: U, override: U, t: T, v: V): U {
+        // { ... T & V } is not assignable to { ... T & U }
+        let tvs: { ...T & V };
+        let mistake: { ...T & U } = tvs;
+            ~~~~~~~
+!!! error TS2322: Type '{ ...T & V }' is not assignable to type '{ ...T & U }'.
+        // { ...U } is not assignable to U
         return { ...initial, ...override };
                ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2322: Type '{ ...U }' is not assignable to type 'U'.
diff --git a/tests/baselines/reference/objectSpreadNegative.js b/tests/baselines/reference/objectSpreadNegative.js
index 452ec457e9ae3..7187b6009bd39 100644
--- a/tests/baselines/reference/objectSpreadNegative.js
+++ b/tests/baselines/reference/objectSpreadNegative.js
@@ -59,8 +59,11 @@ let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: numb
 callableConstructableSpread(12); // error, no call signature
 new callableConstructableSpread(12); // error, no construct signature
 
-// { ...U } is not assignable to U
-function override<U>(initial: U, override: U): U {
+function override<T,U,V>(initial: U, override: U, t: T, v: V): U {
+    // { ... T & V } is not assignable to { ... T & U }
+    let tvs: { ...T & V };
+    let mistake: { ...T & U } = tvs;
+    // { ...U } is not assignable to U
     return { ...initial, ...override };
 }
 
@@ -133,7 +136,10 @@ spreadC.m(); // error 'm' is not in '{ ... c }'
 var callableConstructableSpread;
 callableConstructableSpread(12); // error, no call signature
 new callableConstructableSpread(12); // error, no construct signature
-// { ...U } is not assignable to U
-function override(initial, override) {
+function override(initial, override, t, v) {
+    // { ... T & V } is not assignable to { ... T & U }
+    var tvs;
+    var mistake = tvs;
+    // { ...U } is not assignable to U
     return __assign({}, initial, override);
 }
diff --git a/tests/cases/conformance/types/spread/objectSpreadIntersection.ts b/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
index f70995cb4b2fc..636283dd71545 100644
--- a/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
@@ -2,7 +2,6 @@ function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tu: T | U;
     let uv: U & V;
     let result = { ...tu, ...uv, id: 'foo' };
-    let expected: ({ ...T, ...U, id: string } & { ...T, ...V, id: string }) | ({ ...U, id: string } & { ...U, ...V, id: string });
     let assignable: { ...(T | U), ...(U & V), id: string } = result;
 }
 // concrete types work
@@ -16,21 +15,18 @@ let assignable: { ...(A1 & A2) } = result;
 function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tuv: T & U & V;
     let result = { ...tuv, id: 'bar' };
-    let expected: { ...T, id: string } & { ...U, id: string } & { ...V, id: string } = result;
     let assignable: { ...(T & U & V), id: string } = result;
 }
 function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tu: T & U;
     let uv: U & V;
     let result = { ...tu, ...uv, id: 'baz' };
-    let expected: { ...T, ...U, id: string } & { ...T, ...V, id: string } & { ...U, id: string } & { ...U, ...V, id: string };
     let assignable: { ...(T & U), ...(U & V), id: string } = result;
 }
 function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
     let tu: T & U;
     let uv: U | V;
     let result = { ...tu, ...uv, id: 'qux' };
-    let expected: ({ ...T, ...U, id: string } & { ...U, id: string }) | ({ ...T, ...V, id: string } & { ...U, ...V, id: string });
     let assignable: { ...(T & U), ...(U | V), id: string } = result;
 }
 
diff --git a/tests/cases/conformance/types/spread/objectSpreadNegative.ts b/tests/cases/conformance/types/spread/objectSpreadNegative.ts
index 04a88d2a42738..146ab072bbf17 100644
--- a/tests/cases/conformance/types/spread/objectSpreadNegative.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadNegative.ts
@@ -59,7 +59,10 @@ let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: numb
 callableConstructableSpread(12); // error, no call signature
 new callableConstructableSpread(12); // error, no construct signature
 
-// { ...U } is not assignable to U
-function override<U>(initial: U, override: U): U {
+function override<T,U,V>(initial: U, override: U, t: T, v: V): U {
+    // { ... T & V } is not assignable to { ... T & U }
+    let tvs: { ...T & V };
+    let mistake: { ...T & U } = tvs;
+    // { ...U } is not assignable to U
     return { ...initial, ...override };
 }

From 5e2bd6b063a935d5cb5eda00d200a951cca662bf Mon Sep 17 00:00:00 2001
From: Ron Buckton <rbuckton@microsoft.com>
Date: Thu, 20 Oct 2016 16:44:51 -0700
Subject: [PATCH 065/224] Move System module transform to end.

---
 src/compiler/binder.ts                        |    2 +-
 src/compiler/core.ts                          |   67 +-
 src/compiler/factory.ts                       |   40 +-
 src/compiler/transformer.ts                   |   10 +-
 src/compiler/transformers/destructuring.ts    |   18 +-
 src/compiler/transformers/es2015.ts           |   20 +-
 src/compiler/transformers/module/module.ts    |  683 +++---
 src/compiler/transformers/module/system.ts    | 1967 ++++++++++-------
 src/compiler/transformers/ts.ts               |   31 +-
 src/compiler/types.ts                         |   53 +-
 src/compiler/utilities.ts                     |   50 +-
 .../reference/capturedLetConstInLoop4.js      |    4 +-
 .../reference/dottedNamesInSystem.js          |    2 +-
 .../outFilerootDirModuleNamesSystem.js        |    2 +-
 tests/baselines/reference/systemModule10.js   |    4 +-
 .../baselines/reference/systemModule10_ES5.js |    4 +-
 tests/baselines/reference/systemModule11.js   |   10 +-
 tests/baselines/reference/systemModule13.js   |    6 +-
 tests/baselines/reference/systemModule14.js   |    4 +-
 tests/baselines/reference/systemModule17.js   |    8 +-
 tests/baselines/reference/systemModule3.js    |    4 +-
 tests/baselines/reference/systemModule8.js    |    2 +-
 tests/baselines/reference/systemModule9.js    |    1 -
 ...stemModuleConstEnumsSeparateCompilation.js |    2 +-
 .../systemModuleDeclarationMerging.js         |    2 +-
 .../reference/systemModuleExportDefault.js    |    4 +-
 .../systemModuleNonTopLevelModuleMembers.js   |    2 +-
 .../reference/systemModuleTargetES6.js        |    6 +-
 28 files changed, 1735 insertions(+), 1273 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 2b3584be9e0da..97644000b80b5 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -2485,7 +2485,7 @@ namespace ts {
             && (leftKind === SyntaxKind.ObjectLiteralExpression
                 || leftKind === SyntaxKind.ArrayLiteralExpression)) {
             // Destructuring assignments are ES6 syntax.
-            transformFlags |= TransformFlags.AssertES2015 | TransformFlags.DestructuringAssignment;
+            transformFlags |= TransformFlags.AssertES2015 | TransformFlags.AssertDestructuringAssignment;
         }
         else if (operatorTokenKind === SyntaxKind.AsteriskAsteriskToken
             || operatorTokenKind === SyntaxKind.AsteriskAsteriskEqualsToken) {
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 1dd8ed8ff7f9a..e143d4c434520 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -424,11 +424,16 @@ namespace ts {
 
     export function some<T>(array: T[], predicate?: (value: T) => boolean): boolean {
         if (array) {
-            for (const v of array) {
-                if (!predicate || predicate(v)) {
-                    return true;
+            if (predicate) {
+                for (const v of array) {
+                    if (predicate(v)) {
+                        return true;
+                    }
                 }
             }
+            else {
+                return array.length > 0;
+            }
         }
         return false;
     }
@@ -485,6 +490,14 @@ namespace ts {
         return result;
     }
 
+    /**
+     * Appends a value to an array, returning the array.
+     *
+     * @param to The array to which `value` is to be appended. If `to` is `undefined`, a new array
+     * is created if `value` was appended.
+     * @param value The value to append to the array. If `value` is `undefined`, nothing is
+     * appended.
+     */
     export function append<T>(to: T[] | undefined, value: T | undefined): T[] | undefined {
         if (value === undefined) return to;
         if (to === undefined) to = [];
@@ -492,14 +505,20 @@ namespace ts {
         return to;
     }
 
-    export function addRange<T>(to: T[], from: T[]): void {
-        if (to && from) {
-            for (const v of from) {
-                if (v !== undefined) {
-                    to.push(v);
-                }
-            }
+    /**
+     * Appends a range of value to an array, returning the array.
+     *
+     * @param to The array to which `value` is to be appended. If `to` is `undefined`, a new array
+     * is created if `value` was appended.
+     * @param from The values to append to the array. If `from` is `undefined`, nothing is
+     * appended. If an element of `from` is `undefined`, that element is not appended.
+     */
+    export function addRange<T>(to: T[] | undefined, from: T[] | undefined): T[] | undefined {
+        if (from === undefined) return to;
+        for (const v of from) {
+            to = append(to, v);
         }
+        return to;
     }
 
     export function rangeEquals<T>(array1: T[], array2: T[], pos: number, end: number) {
@@ -512,33 +531,43 @@ namespace ts {
         return true;
     }
 
+    /**
+     * Returns the first element of an array if non-empty, `undefined` otherwise.
+     */
     export function firstOrUndefined<T>(array: T[]): T {
         return array && array.length > 0
             ? array[0]
             : undefined;
     }
 
+    /**
+     * Returns the last element of an array if non-empty, `undefined` otherwise.
+     */
+    export function lastOrUndefined<T>(array: T[]): T {
+        return array && array.length > 0
+            ? array[array.length - 1]
+            : undefined;
+    }
+
+    /**
+     * Returns the only element of an array if it contains only one element, `undefined` otherwise.
+     */
     export function singleOrUndefined<T>(array: T[]): T {
         return array && array.length === 1
             ? array[0]
             : undefined;
     }
 
+    /**
+     * Returns the only element of an array if it contains only one element; otheriwse, returns the
+     * array.
+     */
     export function singleOrMany<T>(array: T[]): T | T[] {
         return array && array.length === 1
             ? array[0]
             : array;
     }
 
-    /**
-     * Returns the last element of an array if non-empty, undefined otherwise.
-     */
-    export function lastOrUndefined<T>(array: T[]): T {
-        return array && array.length > 0
-            ? array[array.length - 1]
-            : undefined;
-    }
-
     /**
      * Performs a binary search, finding the index at which 'value' occurs in 'array'.
      * If no such index is found, returns the 2's-complement of first index at which
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 530d64e8aebe3..2b36afa297c2e 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -1472,6 +1472,17 @@ namespace ts {
         return node;
     }
 
+    /**
+     * Creates a synthetic element to act as a placeholder for the beginning of a merged declaration in
+     * order to properly emit exports.
+     */
+    export function createMergeDeclarationMarker(original: Node) {
+        const node = <MergeDeclarationMarker>createNode(SyntaxKind.MergeDeclarationMarker);
+        node.emitNode = {};
+        node.original = original;
+        return node;
+    }
+
     /**
      * Creates a synthetic expression to act as a placeholder for a not-emitted expression in
      * order to preserve comments or sourcemap positions.
@@ -2206,7 +2217,7 @@ namespace ts {
      * Gets whether an identifier should only be referred to by its local name.
      */
     export function isLocalName(node: Identifier) {
-        return (getEmitFlags(node) & EmitFlags.ExportBindingName) === EmitFlags.LocalName;
+        return (getEmitFlags(node) & EmitFlags.LocalName) !== 0;
     }
 
     /**
@@ -2228,32 +2239,7 @@ namespace ts {
      * name points to an exported symbol.
      */
     export function isExportName(node: Identifier) {
-        return (getEmitFlags(node) & EmitFlags.ExportBindingName) === EmitFlags.ExportName;
-    }
-
-    /**
-     * Gets the export binding name of a declaration for use in the left-hand side of assignment
-     * expressions. This is primarily used for declarations that can be referred to by name in the
-     * declaration's immediate scope (classes, enums, namespaces). If the declaration is exported
-     * and the name is the target of an assignment expression, its export binding name should be
-     * substituted with an expression that assigns *both* the local *and* export names of the
-     * declaration. If an export binding name appears in any other position it should be treated
-     * as a local name.
-     *
-     * @param node The declaration.
-     * @param allowComments A value indicating whether comments may be emitted for the name.
-     * @param allowSourceMaps A value indicating whether source maps may be emitted for the name.
-     */
-    export function getExportBindingName(node: Declaration, allowComments?: boolean, allowSourceMaps?: boolean): Identifier {
-        return getName(node, allowComments, allowSourceMaps, EmitFlags.ExportBindingName);
-    }
-
-    /**
-     * Gets whether an identifier should be treated as both an export name and a local name when
-     * it is the target of an assignment expression.
-     */
-    export function isExportBindingName(node: Identifier) {
-        return (getEmitFlags(node) & EmitFlags.ExportBindingName) === EmitFlags.ExportBindingName;
+        return (getEmitFlags(node) & EmitFlags.ExportName) !== 0;
     }
 
     /**
diff --git a/src/compiler/transformer.ts b/src/compiler/transformer.ts
index 08ff4a55a1a65..6da6a54313b20 100644
--- a/src/compiler/transformer.ts
+++ b/src/compiler/transformer.ts
@@ -112,10 +112,6 @@ namespace ts {
 
         transformers.push(transformTypeScript);
 
-        if (moduleKind === ModuleKind.System) {
-            transformers.push(moduleTransformerMap[moduleKind] || moduleTransformerMap[ModuleKind.None]);
-        }
-
         if (jsx === JsxEmit.React) {
             transformers.push(transformJsx);
         }
@@ -133,10 +129,10 @@ namespace ts {
             transformers.push(transformGenerators);
         }
 
-        if (moduleKind !== ModuleKind.System) {
-            transformers.push(moduleTransformerMap[moduleKind] || moduleTransformerMap[ModuleKind.None]);
-        }
+        transformers.push(moduleTransformerMap[moduleKind] || moduleTransformerMap[ModuleKind.None]);
 
+        // The ES5 transformer is last so that it can substitute expressions like `exports.default`
+        // for ES3.
         if (languageVersion < ScriptTarget.ES5) {
             transformers.push(transformES5);
         }
diff --git a/src/compiler/transformers/destructuring.ts b/src/compiler/transformers/destructuring.ts
index c7219866df7a9..96e9ea23ab778 100644
--- a/src/compiler/transformers/destructuring.ts
+++ b/src/compiler/transformers/destructuring.ts
@@ -176,14 +176,15 @@ namespace ts {
      *
      * @param node The VariableDeclaration to flatten.
      * @param recordTempVariable A callback used to record new temporary variables.
-     * @param nameSubstitution An optional callback used to substitute binding names.
+     * @param createAssignmentCallback An optional callback used to create assignment expressions
+     * for non-temporary variables.
      * @param visitor An optional visitor to use to visit expressions.
      */
     export function flattenVariableDestructuringToExpression(
         context: TransformationContext,
         node: VariableDeclaration,
         recordTempVariable: (name: Identifier) => void,
-        nameSubstitution?: (name: Identifier) => Expression,
+        createAssignmentCallback?: (name: Identifier, value: Expression, location?: TextRange) => Expression,
         visitor?: (node: Node) => VisitResult<Node>) {
 
         const pendingAssignments: Expression[] = [];
@@ -195,18 +196,20 @@ namespace ts {
         return expression;
 
         function emitAssignment(name: Identifier, value: Expression, location: TextRange, original: Node) {
-            const left = nameSubstitution && nameSubstitution(name) || name;
-            emitPendingAssignment(left, value, location, original);
+            const expression = createAssignmentCallback
+                ? createAssignmentCallback(name, value, location)
+                : createAssignment(name, value, location);
+
+            emitPendingAssignment(expression, original);
         }
 
         function emitTempVariableAssignment(value: Expression, location: TextRange) {
             const name = createTempVariable(recordTempVariable);
-            emitPendingAssignment(name, value, location, /*original*/ undefined);
+            emitPendingAssignment(createAssignment(name, value, location), /*original*/ undefined);
             return name;
         }
 
-        function emitPendingAssignment(name: Expression, value: Expression, location: TextRange, original: Node) {
-            const expression = createAssignment(name, value, location);
+        function emitPendingAssignment(expression: Expression, original: Node) {
             expression.original = original;
 
             // NOTE: this completely disables source maps, but aligns with the behavior of
@@ -214,7 +217,6 @@ namespace ts {
             setEmitFlags(expression, EmitFlags.NoNestedSourceMaps);
 
             pendingAssignments.push(expression);
-            return expression;
         }
     }
 
diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
index 8d158cd665eb5..8ba416919fc77 100644
--- a/src/compiler/transformers/es2015.ts
+++ b/src/compiler/transformers/es2015.ts
@@ -585,7 +585,7 @@ namespace ts {
             //      }());
 
             const variable = createVariableDeclaration(
-                getDeclarationName(node, /*allowComments*/ true),
+                getLocalName(node, /*allowComments*/ true),
                 /*type*/ undefined,
                 transformClassLikeDeclarationToExpression(node)
             );
@@ -601,14 +601,12 @@ namespace ts {
 
             // Add an `export default` statement for default exports (for `--target es5 --module es6`)
             if (hasModifier(node, ModifierFlags.Export)) {
-                if (hasModifier(node, ModifierFlags.Default)) {
-                    const exportStatement = createExportDefault(getLocalName(node));
-                    setOriginalNode(exportStatement, statement);
-                    statements.push(exportStatement);
-                }
-                else {
-                    statements.push(createExternalModuleExport(getLocalName(node)));
-                }
+                const exportStatement = hasModifier(node, ModifierFlags.Default)
+                    ? createExportDefault(getLocalName(node))
+                    : createExternalModuleExport(getLocalName(node));
+
+                setOriginalNode(exportStatement, statement);
+                statements.push(exportStatement);
             }
 
             const emitFlags = getEmitFlags(node);
@@ -758,7 +756,7 @@ namespace ts {
             if (extendsClauseElement) {
                 statements.push(
                     createStatement(
-                        createExtendsHelper(currentSourceFile.externalHelpersModuleName, getDeclarationName(node)),
+                        createExtendsHelper(currentSourceFile.externalHelpersModuleName, getLocalName(node)),
                         /*location*/ extendsClauseElement
                     )
                 );
@@ -1694,7 +1692,7 @@ namespace ts {
                     if (decl.initializer) {
                         let assignment: Expression;
                         if (isBindingPattern(decl.name)) {
-                            assignment = flattenVariableDestructuringToExpression(context, decl, hoistVariableDeclaration, /*nameSubstitution*/ undefined, visitor);
+                            assignment = flattenVariableDestructuringToExpression(context, decl, hoistVariableDeclaration, /*createAssignmentCallback*/ undefined, visitor);
                         }
                         else {
                             assignment = createBinary(<Identifier>decl.name, SyntaxKind.EqualsToken, visitNode(decl.initializer, visitor, isExpression));
diff --git a/src/compiler/transformers/module/module.ts b/src/compiler/transformers/module/module.ts
index 2d8a513cc8845..fc193a7850df2 100644
--- a/src/compiler/transformers/module/module.ts
+++ b/src/compiler/transformers/module/module.ts
@@ -4,6 +4,12 @@
 /*@internal*/
 namespace ts {
     export function transformModule(context: TransformationContext) {
+        interface AsynchronousDependencies {
+            aliasedModuleNames: Expression[];
+            unaliasedModuleNames: Expression[];
+            importAliasNames: ParameterDeclaration[];
+        }
+
         const transformModuleDelegates = createMap<(node: SourceFile) => SourceFile>({
             [ModuleKind.None]: transformCommonJSModule,
             [ModuleKind.CommonJS]: transformCommonJSModule,
@@ -48,25 +54,22 @@ namespace ts {
          * @param node The SourceFile node.
          */
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node)) {
+            if (isDeclarationFile(node)
+                || !(isExternalModule(node)
+                    || compilerOptions.isolatedModules)) {
                 return node;
             }
 
-            if (isExternalModule(node) || compilerOptions.isolatedModules) {
-                currentSourceFile = node;
-                currentModuleInfo = moduleInfoMap[getOriginalNodeId(node)] = collectExternalModuleInfo(node, resolver);
-
-                // Perform the transformation.
-                const transformModule = transformModuleDelegates[moduleKind] || transformModuleDelegates[ModuleKind.None];
-                const updated = transformModule(node);
-                aggregateTransformFlags(updated);
+            currentSourceFile = node;
+            currentModuleInfo = moduleInfoMap[getOriginalNodeId(node)] = collectExternalModuleInfo(node, resolver);
 
-                currentSourceFile = undefined;
-                currentModuleInfo = undefined;
-                return updated;
-            }
+            // Perform the transformation.
+            const transformModule = transformModuleDelegates[moduleKind] || transformModuleDelegates[ModuleKind.None];
+            const updated = transformModule(node);
 
-            return node;
+            currentSourceFile = undefined;
+            currentModuleInfo = undefined;
+            return aggregateTransformFlags(updated);
         }
 
         /**
@@ -78,8 +81,8 @@ namespace ts {
             startLexicalEnvironment();
 
             const statements: Statement[] = [];
-            const statementOffset = addPrologueDirectives(statements, node.statements, /*ensureUseStrict*/ !compilerOptions.noImplicitUseStrict, visitor);
-            addRange(statements, visitNodes(node.statements, visitor, isStatement, statementOffset));
+            const statementOffset = addPrologueDirectives(statements, node.statements, /*ensureUseStrict*/ !compilerOptions.noImplicitUseStrict, sourceElementVisitor);
+            addRange(statements, visitNodes(node.statements, sourceElementVisitor, isStatement, statementOffset));
             addRange(statements, endLexicalEnvironment());
             addExportEqualsIfNeeded(statements, /*emitAsReturn*/ false);
 
@@ -192,6 +195,56 @@ namespace ts {
             );
         }
 
+        /**
+         * Collect the additional asynchronous dependencies for the module.
+         *
+         * @param node The source file.
+         * @param includeNonAmdDependencies A value indicating whether to include non-AMD dependencies.
+         */
+        function collectAsynchronousDependencies(node: SourceFile, includeNonAmdDependencies: boolean): AsynchronousDependencies {
+            // names of modules with corresponding parameter in the factory function
+            const aliasedModuleNames: Expression[] = [];
+
+            // names of modules with no corresponding parameters in factory function
+            const unaliasedModuleNames: Expression[] = [];
+
+            // names of the parameters in the factory function; these
+            // parameters need to match the indexes of the corresponding
+            // module names in aliasedModuleNames.
+            const importAliasNames: ParameterDeclaration[] = [];
+
+            // Fill in amd-dependency tags
+            for (const amdDependency of node.amdDependencies) {
+                if (amdDependency.name) {
+                    aliasedModuleNames.push(createLiteral(amdDependency.path));
+                    importAliasNames.push(createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, amdDependency.name));
+                }
+                else {
+                    unaliasedModuleNames.push(createLiteral(amdDependency.path));
+                }
+            }
+
+            for (const importNode of currentModuleInfo.externalImports) {
+                // Find the name of the external module
+                const externalModuleName = getExternalModuleNameLiteral(importNode, currentSourceFile, host, resolver, compilerOptions);
+
+                // Find the name of the module alias, if there is one
+                const importAliasName = getLocalNameForExternalImport(importNode, currentSourceFile);
+                if (includeNonAmdDependencies && importAliasName) {
+                    // Set emitFlags on the name of the classDeclaration
+                    // This is so that when printer will not substitute the identifier
+                    setEmitFlags(importAliasName, EmitFlags.NoSubstitution);
+                    aliasedModuleNames.push(externalModuleName);
+                    importAliasNames.push(createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, importAliasName));
+                }
+                else {
+                    unaliasedModuleNames.push(externalModuleName);
+                }
+            }
+
+            return { aliasedModuleNames, unaliasedModuleNames, importAliasNames };
+        }
+
         /**
          * Transforms a SourceFile into an AMD or UMD module body.
          *
@@ -201,10 +254,10 @@ namespace ts {
             startLexicalEnvironment();
 
             const statements: Statement[] = [];
-            const statementOffset = addPrologueDirectives(statements, node.statements, /*ensureUseStrict*/ !compilerOptions.noImplicitUseStrict, visitor);
+            const statementOffset = addPrologueDirectives(statements, node.statements, /*ensureUseStrict*/ !compilerOptions.noImplicitUseStrict, sourceElementVisitor);
 
             // Visit each statement of the module body.
-            addRange(statements, visitNodes(node.statements, visitor, isStatement, statementOffset));
+            addRange(statements, visitNodes(node.statements, sourceElementVisitor, isStatement, statementOffset));
 
             // End the lexical environment for the module body
             // and merge any new lexical declarations.
@@ -223,12 +276,53 @@ namespace ts {
             return body;
         }
 
+        /**
+         * Adds the down-level representation of `export=` to the statement list if one exists
+         * in the source file.
+         *
+         * @param statements The Statement list to modify.
+         * @param emitAsReturn A value indicating whether to emit the `export=` statement as a
+         * return statement.
+         */
+        function addExportEqualsIfNeeded(statements: Statement[], emitAsReturn: boolean) {
+            if (currentModuleInfo.exportEquals) {
+                if (emitAsReturn) {
+                    const statement = createReturn(
+                        currentModuleInfo.exportEquals.expression,
+                        /*location*/ currentModuleInfo.exportEquals
+                    );
+
+                    setEmitFlags(statement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoComments);
+                    statements.push(statement);
+                }
+                else {
+                    const statement = createStatement(
+                        createAssignment(
+                            createPropertyAccess(
+                                createIdentifier("module"),
+                                "exports"
+                            ),
+                            currentModuleInfo.exportEquals.expression
+                        ),
+                        /*location*/ currentModuleInfo.exportEquals
+                    );
+
+                    setEmitFlags(statement, EmitFlags.NoComments);
+                    statements.push(statement);
+                }
+            }
+        }
+
+        //
+        // Top-Level Source Element Visitors
+        //
+
         /**
          * Visits a node at the top level of the source file.
          *
-         * @param node The node.
+         * @param node The node to visit.
          */
-        function visitor(node: Node): VisitResult<Node> {
+        function sourceElementVisitor(node: Node): VisitResult<Node> {
             switch (node.kind) {
                 case SyntaxKind.ImportDeclaration:
                     return visitImportDeclaration(<ImportDeclaration>node);
@@ -251,8 +345,8 @@ namespace ts {
                 case SyntaxKind.ClassDeclaration:
                     return visitClassDeclaration(<ClassDeclaration>node);
 
-                case SyntaxKind.NotEmittedStatement:
-                    return visitNotEmittedStatement(<NotEmittedStatement>node);
+                case SyntaxKind.MergeDeclarationMarker:
+                    return visitMergeDeclarationMarker(<MergeDeclarationMarker>node);
 
                 case SyntaxKind.EndOfDeclarationMarker:
                     return visitEndOfDeclarationMarker(<EndOfDeclarationMarker>node);
@@ -264,26 +358,10 @@ namespace ts {
             }
         }
 
-        /**
-         * Visits a modifier.
-         *
-         * @param node The modifier.
-         */
-        function modifierVisitor(node: Node): VisitResult<Node> {
-            // Elide module-specific modifiers.
-            switch (node.kind) {
-                case SyntaxKind.ExportKeyword:
-                case SyntaxKind.DefaultKeyword:
-                    return undefined;
-            }
-
-            return node;
-        }
-
         /**
          * Visits an ImportDeclaration node.
          *
-         * @param node The ImportDeclaration node
+         * @param node The node to visit.
          */
         function visitImportDeclaration(node: ImportDeclaration): VisitResult<Statement> {
             let statements: Statement[];
@@ -363,14 +441,37 @@ namespace ts {
                 );
             }
 
-            statements = appendExportsOfImportDeclaration(statements, node);
+            if (hasAssociatedEndOfDeclarationMarker(node)) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportsOfImportDeclaration(deferredExports[id], node);
+            }
+            else {
+                statements = appendExportsOfImportDeclaration(statements, node);
+            }
+
             return singleOrMany(statements);
         }
 
+        /**
+         * Creates a `require()` call to import an external module.
+         *
+         * @param importNode The declararation to import.
+         */
+        function createRequireCall(importNode: ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration) {
+            const moduleName = getExternalModuleNameLiteral(importNode, currentSourceFile, host, resolver, compilerOptions);
+            const args: Expression[] = [];
+            if (moduleName) {
+                args.push(moduleName);
+            }
+
+            return createCall(createIdentifier("require"), /*typeArguments*/ undefined, args);
+        }
+
         /**
          * Visits an ImportEqualsDeclaration node.
          *
-         * @param node The ImportEqualsDeclaration node
+         * @param node The node to visit.
          */
         function visitImportEqualsDeclaration(node: ImportEqualsDeclaration): VisitResult<Statement> {
             Debug.assert(isExternalModuleImportEqualsDeclaration(node), "import= for internal module references should be handled in an earlier transformer.");
@@ -380,7 +481,7 @@ namespace ts {
                 if (hasModifier(node, ModifierFlags.Export)) {
                     statements = append(statements,
                         createStatement(
-                            createExportAssignment(
+                            createExportExpression(
                                 node.name,
                                 createRequireCall(node)
                             ),
@@ -412,7 +513,7 @@ namespace ts {
                 if (hasModifier(node, ModifierFlags.Export)) {
                     statements = append(statements,
                         createStatement(
-                            createExportAssignment(getExportName(node), getLocalName(node)),
+                            createExportExpression(getExportName(node), getLocalName(node)),
                             /*location*/ node
                         )
                     );
@@ -420,6 +521,7 @@ namespace ts {
             }
 
             if (hasAssociatedEndOfDeclarationMarker(node)) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
                 deferredExports[id] = appendExportsOfImportEqualsDeclaration(deferredExports[id], node);
             }
@@ -433,7 +535,7 @@ namespace ts {
         /**
          * Visits an ExportDeclaration node.
          *
-         * @param The ExportDeclaration node
+         * @param The node to visit.
          */
         function visitExportDeclaration(node: ExportDeclaration): VisitResult<Statement> {
             if (!node.moduleSpecifier) {
@@ -468,7 +570,7 @@ namespace ts {
                     );
                     statements.push(
                         createStatement(
-                            createExportAssignment(getExportName(specifier), exportedValue),
+                            createExportExpression(getExportName(specifier), exportedValue),
                             /*location*/ specifier
                         )
                     );
@@ -496,7 +598,7 @@ namespace ts {
         /**
          * Visits an ExportAssignment node.
          *
-         * @param node The ExportAssignment node
+         * @param node The node to visit.
          */
         function visitExportAssignment(node: ExportAssignment): VisitResult<Statement> {
             if (node.isExportEquals) {
@@ -518,84 +620,9 @@ namespace ts {
         }
 
         /**
-         * Visits a VariableStatement.
-         *
-         * @param node A VariableStatement node.
-         */
-        function visitVariableStatement(node: VariableStatement): VisitResult<Statement> {
-            let statements: Statement[];
-            let variables: VariableDeclaration[];
-            let expressions: Expression[];
-            if (hasModifier(node, ModifierFlags.Export)) {
-                let modifiers: NodeArray<Modifier>;
-
-                // If we're exporting these variables, then these just become assignments to 'exports.x'.
-                // We only want to emit assignments for variables with initializers.
-                for (const variable of node.declarationList.declarations) {
-                    if (isIdentifier(variable.name) && isLocalName(variable.name)) {
-                        if (!modifiers) {
-                            modifiers = visitNodes(node.modifiers, modifierVisitor, isModifier);
-                        }
-
-                        variables = append(variables, variable);
-                    }
-                    else if (variable.initializer) {
-                        expressions = append(expressions, transformInitializedVariable(variable));
-                    }
-                }
-
-                if (variables) {
-                    statements = append(statements, updateVariableStatement(node, modifiers, updateVariableDeclarationList(node.declarationList, variables)));
-                }
-
-                if (expressions) {
-                    statements = append(statements, createStatement(inlineExpressions(expressions), /*location*/ node));
-                }
-            }
-            else {
-                statements = append(statements, node);
-            }
-
-            if (hasAssociatedEndOfDeclarationMarker(node)) {
-                // Defer exports until we encounter an EndOfDeclarationMarker node
-                const id = getOriginalNodeId(node);
-                deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], node);
-            }
-            else {
-                statements = appendExportsOfVariableStatement(statements, node);
-            }
-
-            // statements = addExportsOfVariableStatement(statements, node);
-            return singleOrMany(statements);
-        }
-
-        /**
-         * Transforms an exported variable with an initializer into an expression.
-         *
-         * @param node The variable to transform.
-         */
-        function transformInitializedVariable(node: VariableDeclaration): Expression {
-            const name = node.name;
-            if (isBindingPattern(name)) {
-                return flattenVariableDestructuringToExpression(
-                    context,
-                    node,
-                    hoistVariableDeclaration,
-                    getModuleMemberName
-                );
-            }
-            else {
-                return createAssignment(
-                    getModuleMemberName(name),
-                    node.initializer
-                );
-            }
-        }
-
-        /**
-         * Visits a FunctionDeclaration.
+         * Visits a FunctionDeclaration node.
          *
-         * @param node A FunctionDeclaration node.
+         * @param node The node to visit.
          */
         function visitFunctionDeclaration(node: FunctionDeclaration): VisitResult<Statement> {
             let statements: Statement[];
@@ -634,9 +661,9 @@ namespace ts {
         }
 
         /**
-         * Visits a ClassDeclaration.
+         * Visits a ClassDeclaration node.
          *
-         * @param node A ClassDeclaration node.
+         * @param node The node to visit.
          */
         function visitClassDeclaration(node: ClassDeclaration): VisitResult<Statement> {
             let statements: Statement[];
@@ -673,19 +700,97 @@ namespace ts {
         }
 
         /**
-         * Visits a NotEmittedStatement.
+         * Visits a VariableStatement node.
          *
-         * @param node A NotEmittedStatement node.
+         * @param node The node to visit.
          */
-        function visitNotEmittedStatement(node: NotEmittedStatement): VisitResult<Statement> {
+        function visitVariableStatement(node: VariableStatement): VisitResult<Statement> {
+            let statements: Statement[];
+            let variables: VariableDeclaration[];
+            let expressions: Expression[];
+            if (hasModifier(node, ModifierFlags.Export)) {
+                let modifiers: NodeArray<Modifier>;
+
+                // If we're exporting these variables, then these just become assignments to 'exports.x'.
+                // We only want to emit assignments for variables with initializers.
+                for (const variable of node.declarationList.declarations) {
+                    if (isIdentifier(variable.name) && isLocalName(variable.name)) {
+                        if (!modifiers) {
+                            modifiers = visitNodes(node.modifiers, modifierVisitor, isModifier);
+                        }
+
+                        variables = append(variables, variable);
+                    }
+                    else if (variable.initializer) {
+                        expressions = append(expressions, transformInitializedVariable(variable));
+                    }
+                }
+
+                if (variables) {
+                    statements = append(statements, updateVariableStatement(node, modifiers, updateVariableDeclarationList(node.declarationList, variables)));
+                }
+
+                if (expressions) {
+                    statements = append(statements, createStatement(inlineExpressions(expressions), /*location*/ node));
+                }
+            }
+            else {
+                statements = append(statements, node);
+            }
+
+            if (hasAssociatedEndOfDeclarationMarker(node)) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], node);
+            }
+            else {
+                statements = appendExportsOfVariableStatement(statements, node);
+            }
+
+            return singleOrMany(statements);
+        }
+
+        /**
+         * Transforms an exported variable with an initializer into an expression.
+         *
+         * @param node The node to transform.
+         */
+        function transformInitializedVariable(node: VariableDeclaration): Expression {
+            if (isBindingPattern(node.name)) {
+                return flattenVariableDestructuringToExpression(
+                    context,
+                    node,
+                    hoistVariableDeclaration,
+                    createExportExpression
+                );
+            }
+            else {
+                return createAssignment(
+                    createPropertyAccess(
+                        createIdentifier("exports"),
+                        node.name,
+                        /*location*/ node.name
+                    ),
+                    node.initializer
+                );
+            }
+        }
+
+        /**
+         * Visits a MergeDeclarationMarker used as a placeholder for the beginning of a merged
+         * and transformed declaration.
+         *
+         * @param node The node to visit.
+         */
+        function visitMergeDeclarationMarker(node: MergeDeclarationMarker): VisitResult<Statement> {
             // For an EnumDeclaration or ModuleDeclaration that merges with a preceeding
             // declaration we do not emit a leading variable declaration. To preserve the
             // begin/end semantics of the declararation and to properly handle exports
-            // we wrap the leading variable declaration in a `NotEmittedStatement`.
+            // we wrapped the leading variable declaration in a `MergeDeclarationMarker`.
             //
             // To balance the declaration, add the exports of the elided variable
             // statement.
-            if (hasAssociatedEndOfDeclarationMarker(node.original) && node.original.kind === SyntaxKind.VariableStatement) {
+            if (hasAssociatedEndOfDeclarationMarker(node) && node.original.kind === SyntaxKind.VariableStatement) {
                 const id = getOriginalNodeId(node);
                 deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], <VariableStatement>node.original);
             }
@@ -694,9 +799,19 @@ namespace ts {
         }
 
         /**
-         * Visits a DeclarationMarker used as a placeholder for the end of a transformed declaration.
+         * Determines whether a node has an associated EndOfDeclarationMarker.
+         *
+         * @param node The node to test.
+         */
+        function hasAssociatedEndOfDeclarationMarker(node: Node) {
+            return (getEmitFlags(node) & EmitFlags.HasEndOfDeclarationMarker) !== 0;
+        }
+
+        /**
+         * Visits a DeclarationMarker used as a placeholder for the end of a transformed
+         * declaration.
          *
-         * @param node A DeclarationMarker node.
+         * @param node The node to visit.
          */
         function visitEndOfDeclarationMarker(node: EndOfDeclarationMarker): VisitResult<Statement> {
             // For some transformations we emit an `EndOfDeclarationMarker` to mark the actual
@@ -716,10 +831,9 @@ namespace ts {
          * Appends the exports of an ImportDeclaration to a statement list, returning the
          * statement list.
          *
-         * If `statements` is `undefined`, a new array is allocated if statements are appended.
-         *
          * @param statements A statement list to which the down-level export statements are to be
-         *  appended.
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
          * @param decl The declaration whose exports are to be recorded.
          */
         function appendExportsOfImportDeclaration(statements: Statement[] | undefined, decl: ImportDeclaration): Statement[] | undefined {
@@ -728,25 +842,27 @@ namespace ts {
             }
 
             const importClause = decl.importClause;
-            if (importClause) {
-                if (importClause.name) {
-                    statements = appendExportsOfDeclaration(statements, importClause);
-                }
+            if (!importClause) {
+                return statements;
+            }
 
-                const namedBindings = importClause.namedBindings;
-                if (namedBindings) {
-                    switch (namedBindings.kind) {
-                        case SyntaxKind.NamespaceImport:
-                            statements = appendExportsOfDeclaration(statements, namedBindings);
-                            break;
+            if (importClause.name) {
+                statements = appendExportsOfDeclaration(statements, importClause);
+            }
 
-                        case SyntaxKind.NamedImports:
-                            for (const importBinding of namedBindings.elements) {
-                                statements = appendExportsOfDeclaration(statements, importBinding);
-                            }
+            const namedBindings = importClause.namedBindings;
+            if (namedBindings) {
+                switch (namedBindings.kind) {
+                    case SyntaxKind.NamespaceImport:
+                        statements = appendExportsOfDeclaration(statements, namedBindings);
+                        break;
 
-                            break;
-                    }
+                    case SyntaxKind.NamedImports:
+                        for (const importBinding of namedBindings.elements) {
+                            statements = appendExportsOfDeclaration(statements, importBinding);
+                        }
+
+                        break;
                 }
             }
 
@@ -757,10 +873,9 @@ namespace ts {
          * Appends the exports of an ImportEqualsDeclaration to a statement list, returning the
          * statement list.
          *
-         * If `statements` is `undefined`, a new array is allocated if statements are appended.
-         *
          * @param statements A statement list to which the down-level export statements are to be
-         *  appended.
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
          * @param decl The declaration whose exports are to be recorded.
          */
         function appendExportsOfImportEqualsDeclaration(statements: Statement[] | undefined, decl: ImportEqualsDeclaration): Statement[] | undefined {
@@ -775,10 +890,9 @@ namespace ts {
          * Appends the exports of a VariableStatement to a statement list, returning the statement
          * list.
          *
-         * If `statements` is `undefined`, a new array is allocated if statements are appended.
-         *
          * @param statements A statement list to which the down-level export statements are to be
-         *  appended.
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
          * @param node The VariableStatement whose exports are to be recorded.
          */
         function appendExportsOfVariableStatement(statements: Statement[] | undefined, node: VariableStatement): Statement[] | undefined {
@@ -797,10 +911,9 @@ namespace ts {
          * Appends the exports of a VariableDeclaration or BindingElement to a statement list,
          * returning the statement list.
          *
-         * If `statements` is `undefined`, a new array is allocated if statements are appended.
-         *
          * @param statements A statement list to which the down-level export statements are to be
-         *  appended.
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
          * @param decl The declaration whose exports are to be recorded.
          */
         function appendExportsOfBindingElement(statements: Statement[] | undefined, decl: VariableDeclaration | BindingElement): Statement[] | undefined {
@@ -826,9 +939,8 @@ namespace ts {
          * Appends the exports of a ClassDeclaration or FunctionDeclaration to a statement list,
          * returning the statement list.
          *
-         * If `statements` is `undefined`, a new array is allocated if statements are appended.
-         *
          * @param statements A statement list to which the down-level export statements are to be
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
          * appended.
          * @param decl The declaration whose exports are to be recorded.
          */
@@ -852,10 +964,9 @@ namespace ts {
         /**
          * Appends the exports of a declaration to a statement list, returning the statement list.
          *
-         * If `statements` is `undefined`, a new array is allocated if statements are appended.
-         *
          * @param statements A statement list to which the down-level export statements are to be
-         *  appended.
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
          * @param decl The declaration to export.
          */
         function appendExportsOfDeclaration(statements: Statement[] | undefined, decl: Declaration): Statement[] | undefined {
@@ -873,9 +984,9 @@ namespace ts {
          * Appends the down-level representation of an export to a statement list, returning the
          * statement list.
          *
-         * If `statements` is `undefined`, a new array is allocated if statements are appended.
-         *
-         * @param statements The statement list to modify.
+         * @param statements A statement list to which the down-level export statements are to be
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
          * @param exportName The name of the export.
          * @param expression The expression to export.
          * @param location The location to use for source maps and comments for the export.
@@ -888,7 +999,7 @@ namespace ts {
                     if (languageVersion === ScriptTarget.ES3) {
                         statements = append(statements,
                             createStatement(
-                                createExportAssignment(
+                                createExportExpression(
                                     createIdentifier("__esModule"),
                                     createLiteral(true)
                                 )
@@ -920,56 +1031,71 @@ namespace ts {
         }
 
         /**
-         * Adds the down-level representation of `export=` to the statement list if one exists
-         * in the source file.
+         * Creates a call to the current file's export function to export a value.
          *
-         * @param statements The Statement list to modify.
-         * @param emitAsReturn A value indicating whether to emit the `export=` statement as a
-         *  return statement.
+         * @param name The bound name of the export.
+         * @param value The exported value.
+         * @param location The location to use for source maps and comments for the export.
+         * @param allowComments An optional value indicating whether to emit comments for the statement.
          */
-        function addExportEqualsIfNeeded(statements: Statement[], emitAsReturn: boolean) {
-            if (currentModuleInfo.exportEquals) {
-                if (emitAsReturn) {
-                    const statement = createReturn(
-                        currentModuleInfo.exportEquals.expression,
-                        /*location*/ currentModuleInfo.exportEquals
-                    );
+        function createExportStatement(name: Identifier, value: Expression, location?: TextRange, allowComments?: boolean) {
+            const statement = createStatement(createExportExpression(name, value), location);
+            startOnNewLine(statement);
+            if (!allowComments) {
+                setEmitFlags(statement, EmitFlags.NoComments);
+            }
 
-                    setEmitFlags(statement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoComments);
-                    statements.push(statement);
-                }
-                else {
-                    const statement = createStatement(
-                        createAssignment(
-                            createPropertyAccess(
-                                createIdentifier("module"),
-                                "exports"
-                            ),
-                            currentModuleInfo.exportEquals.expression
-                        ),
-                        /*location*/ currentModuleInfo.exportEquals
-                    );
+            return statement;
+        }
 
-                    setEmitFlags(statement, EmitFlags.NoComments);
-                    statements.push(statement);
-                }
-            }
+        /**
+         * Creates a call to the current file's export function to export a value.
+         *
+         * @param name The bound name of the export.
+         * @param value The exported value.
+         * @param location The location to use for source maps and comments for the export.
+         */
+        function createExportExpression(name: Identifier, value: Expression, location?: TextRange) {
+            return createAssignment(
+                createPropertyAccess(
+                    createIdentifier("exports"),
+                    getSynthesizedClone(name)
+                ),
+                value,
+                location
+            );
         }
 
+        //
+        // Modifier Visitors
+        //
+
         /**
-         * Determines whether a node has an associated EndDeclarationMarker.
+         * Visit nodes to elide module-specific modifiers.
          *
-         * @param node The node to test.
+         * @param node The node to visit.
          */
-        function hasAssociatedEndOfDeclarationMarker(node: Node) {
-            return (getEmitFlags(node) & EmitFlags.HasEndOfDeclarationMarker) !== 0;
+        function modifierVisitor(node: Node): VisitResult<Node> {
+            // Elide module-specific modifiers.
+            switch (node.kind) {
+                case SyntaxKind.ExportKeyword:
+                case SyntaxKind.DefaultKeyword:
+                    return undefined;
+            }
+
+            return node;
         }
 
+        //
+        // Emit Notification
+        //
+
         /**
-         * Hook for node emit.
+         * Hook for node emit notifications.
          *
+         * @param emitContext A context hint for the emitter.
          * @param node The node to emit.
-         * @param emitCallback A callback used to emit the node in the printer.
+         * @param emit A callback used to emit the node in the printer.
          */
         function onEmitNode(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void {
             if (node.kind === SyntaxKind.SourceFile) {
@@ -988,12 +1114,15 @@ namespace ts {
             }
         }
 
+        //
+        // Substitutions
+        //
+
         /**
          * Hooks node substitutions.
          *
+         * @param emitContext A context hint for the emitter.
          * @param node The node to substitute.
-         * @param isExpression A value indicating whether the node is to be used in an expression
-         *                     position.
          */
         function onSubstituteNode(emitContext: EmitContext, node: Node) {
             node = previousOnSubstituteNode(emitContext, node);
@@ -1015,7 +1144,7 @@ namespace ts {
          * Substitution for a ShorthandPropertyAssignment whose declaration name is an imported
          * or exported symbol.
          *
-         * @param node A ShorthandPropertyAssignment
+         * @param node The node to substitute.
          */
         function substituteShorthandPropertyAssignment(node: ShorthandPropertyAssignment): ObjectLiteralElementLike {
             const name = node.name;
@@ -1035,7 +1164,7 @@ namespace ts {
         /**
          * Substitution for an Expression that may contain an imported or exported symbol.
          *
-         * @param node An Expression
+         * @param node The node to substitute.
          */
         function substituteExpression(node: Expression) {
             switch (node.kind) {
@@ -1052,14 +1181,14 @@ namespace ts {
         }
 
         /**
-         * Substitution for an Identifier expression that may contain an imported or exported symbol.
+         * Substitution for an Identifier expression that may contain an imported or exported
+         * symbol.
          *
-         * @param node An Identifier expression
+         * @param node The node to substitute.
          */
         function substituteExpressionIdentifier(node: Identifier): Expression {
-            const emitFlags = getEmitFlags(node);
-            if ((emitFlags & EmitFlags.LocalName) === 0) {
-                const exportContainer = resolver.getReferencedExportContainer(node, (emitFlags & EmitFlags.ExportName) !== 0);
+            if (!isGeneratedIdentifier(node) && !isLocalName(node)) {
+                const exportContainer = resolver.getReferencedExportContainer(node, isExportName(node));
                 if (exportContainer && exportContainer.kind === SyntaxKind.SourceFile) {
                     return createPropertyAccess(
                         createIdentifier("exports"),
@@ -1093,7 +1222,7 @@ namespace ts {
         /**
          * Substitution for a BinaryExpression that may contain an imported or exported symbol.
          *
-         * @param node A BinaryExpression
+         * @param node The node to substitute.
          */
         function substituteBinaryExpression(node: BinaryExpression): Expression {
             // When we see an assignment expression whose left-hand side is an exported symbol,
@@ -1109,19 +1238,14 @@ namespace ts {
                 && !isGeneratedIdentifier(node.left)
                 && !isLocalName(node.left)
                 && !isDeclarationNameOfEnumOrNamespace(node.left)) {
-                const exportedNames = getExportsOfName(node.left);
+                const exportedNames = getExports(node.left);
                 if (exportedNames) {
-                    // Since we will be reusing this node as part of the substitution, we
-                    // mark it to prevent triggering this rule again.
-                    noSubstitution[getNodeId(node)] = true;
-
+                    // For each additional export of the declaration, apply an export assignment.
                     let expression: Expression = node;
                     for (const exportName of exportedNames) {
-                        expression = createExportAssignment(exportName, expression);
-
-                        // Mark the transformed node to prevent possibly triggering this rule
-                        // again.
+                        // Mark the node to prevent triggering this rule again.
                         noSubstitution[getNodeId(expression)] = true;
+                        expression = createExportExpression(exportName, expression, /*location*/ node);
                     }
 
                     return expression;
@@ -1134,7 +1258,7 @@ namespace ts {
         /**
          * Substitution for a UnaryExpression that may contain an imported or exported symbol.
          *
-         * @param node A UnaryExpression.
+         * @param node The node to substitute.
          */
         function substituteUnaryExpression(node: PrefixUnaryExpression | PostfixUnaryExpression): Expression {
             // When we see a prefix or postfix increment expression whose operand is an exported
@@ -1146,29 +1270,24 @@ namespace ts {
             // - We do not substitute identifiers that were originally the name of an enum or
             //   namespace due to how they are transformed in TypeScript.
             // - We only substitute identifiers that are exported at the top level.
-            if (isIdentifier(node.operand)
+            if ((node.operator === SyntaxKind.PlusPlusToken || node.operator === SyntaxKind.MinusMinusToken)
+                && isIdentifier(node.operand)
                 && !isGeneratedIdentifier(node.operand)
                 && !isLocalName(node.operand)
                 && !isDeclarationNameOfEnumOrNamespace(node.operand)) {
-                const exportedNames = getExportsOfName(node.operand);
+                const exportedNames = getExports(node.operand);
                 if (exportedNames) {
-                    let expression = node.kind === SyntaxKind.PostfixUnaryExpression
+                    let expression: Expression = node.kind === SyntaxKind.PostfixUnaryExpression
                         ? createBinary(
                             node.operand,
                             createToken(node.operator === SyntaxKind.PlusPlusToken ? SyntaxKind.PlusEqualsToken : SyntaxKind.MinusEqualsToken),
                             createLiteral(1),
                             /*location*/ node)
                         : node;
-
-                    // Since we will be reusing this node as part of the substitution, we
-                    // mark it to prevent triggering this rule again.
-                    noSubstitution[getNodeId(expression)] = true;
-
                     for (const exportName of exportedNames) {
-                        expression = createExportAssignment(exportName, expression);
-                        // Mark the transformed node to prevent triggering the assignment
-                        // expression substitution in `substituteBinaryExpression`.
+                        // Mark the node to prevent triggering this rule again.
                         noSubstitution[getNodeId(expression)] = true;
+                        expression = createExportExpression(exportName, expression);
                     }
 
                     return expression;
@@ -1179,11 +1298,11 @@ namespace ts {
         }
 
         /**
-         * Gets the exports of a name.
+         * Gets the additional exports of a name.
          *
          * @param name The name.
          */
-        function getExportsOfName(name: Identifier): Identifier[] | undefined {
+        function getExports(name: Identifier): Identifier[] | undefined {
             if (!isGeneratedIdentifier(name)) {
                 const valueDeclaration = resolver.getReferencedImportDeclaration(name)
                     || resolver.getReferencedValueDeclaration(name);
@@ -1193,93 +1312,5 @@ namespace ts {
                 }
             }
         }
-
-        function getModuleMemberName(name: Identifier) {
-            return createPropertyAccess(
-                createIdentifier("exports"),
-                name,
-                /*location*/ name
-            );
-        }
-
-        function createRequireCall(importNode: ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration) {
-            const moduleName = getExternalModuleNameLiteral(importNode, currentSourceFile, host, resolver, compilerOptions);
-            const args: Expression[] = [];
-            if (moduleName) {
-                args.push(moduleName);
-            }
-
-            return createCall(createIdentifier("require"), /*typeArguments*/ undefined, args);
-        }
-
-        function createExportStatement(name: Identifier, value: Expression, location?: TextRange, allowComments?: boolean) {
-            const statement = createStatement(createExportAssignment(name, value), location);
-            startOnNewLine(statement);
-            if (!allowComments) {
-                setEmitFlags(statement, EmitFlags.NoComments);
-            }
-
-            return statement;
-        }
-
-        function createExportAssignment(name: Identifier, value: Expression) {
-            return createAssignment(
-                createPropertyAccess(
-                    createIdentifier("exports"),
-                    getSynthesizedClone(name)
-                ),
-                value
-            );
-        }
-
-        interface AsynchronousDependencies {
-            aliasedModuleNames: Expression[];
-            unaliasedModuleNames: Expression[];
-            importAliasNames: ParameterDeclaration[];
-        }
-
-        function collectAsynchronousDependencies(node: SourceFile, includeNonAmdDependencies: boolean): AsynchronousDependencies {
-            // names of modules with corresponding parameter in the factory function
-            const aliasedModuleNames: Expression[] = [];
-
-            // names of modules with no corresponding parameters in factory function
-            const unaliasedModuleNames: Expression[] = [];
-
-            // names of the parameters in the factory function; these
-            // parameters need to match the indexes of the corresponding
-            // module names in aliasedModuleNames.
-            const importAliasNames: ParameterDeclaration[] = [];
-
-            // Fill in amd-dependency tags
-            for (const amdDependency of node.amdDependencies) {
-                if (amdDependency.name) {
-                    aliasedModuleNames.push(createLiteral(amdDependency.path));
-                    importAliasNames.push(createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, amdDependency.name));
-                }
-                else {
-                    unaliasedModuleNames.push(createLiteral(amdDependency.path));
-                }
-            }
-
-            for (const importNode of currentModuleInfo.externalImports) {
-                // Find the name of the external module
-                const externalModuleName = getExternalModuleNameLiteral(importNode, currentSourceFile, host, resolver, compilerOptions);
-
-                // Find the name of the module alias, if there is one
-                const importAliasName = getLocalNameForExternalImport(importNode, currentSourceFile);
-                if (includeNonAmdDependencies && importAliasName) {
-                    // Set emitFlags on the name of the classDeclaration
-                    // This is so that when printer will not substitute the identifier
-                    setEmitFlags(importAliasName, EmitFlags.NoSubstitution);
-                    aliasedModuleNames.push(externalModuleName);
-                    importAliasNames.push(createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, importAliasName));
-                }
-                else {
-                    unaliasedModuleNames.push(externalModuleName);
-                }
-            }
-
-            return { aliasedModuleNames, unaliasedModuleNames, importAliasNames };
-        }
     }
 }
diff --git a/src/compiler/transformers/module/system.ts b/src/compiler/transformers/module/system.ts
index 8bea1e3d28a3c..f1267831719c6 100644
--- a/src/compiler/transformers/module/system.ts
+++ b/src/compiler/transformers/module/system.ts
@@ -12,8 +12,7 @@ namespace ts {
         const {
             startLexicalEnvironment,
             endLexicalEnvironment,
-            hoistVariableDeclaration,
-            hoistFunctionDeclaration,
+            hoistVariableDeclaration
         } = context;
 
         const compilerOptions = context.getCompilerOptions();
@@ -23,58 +22,43 @@ namespace ts {
         const previousOnEmitNode = context.onEmitNode;
         context.onSubstituteNode = onSubstituteNode;
         context.onEmitNode = onEmitNode;
-        context.enableSubstitution(SyntaxKind.Identifier);
-        context.enableSubstitution(SyntaxKind.BinaryExpression);
-        context.enableSubstitution(SyntaxKind.PrefixUnaryExpression);
-        context.enableSubstitution(SyntaxKind.PostfixUnaryExpression);
-        context.enableEmitNotification(SyntaxKind.SourceFile);
-
-        const exportFunctionForFileMap: Identifier[] = [];
-        let currentSourceFile: SourceFile;
-        let externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[];
-        let exportSpecifiers: Map<ExportSpecifier[]>;
-        let exportEquals: ExportAssignment;
-        let hasExportStarsToExportValues: boolean;
-        let exportFunctionForFile: Identifier;
-        let contextObjectForFile: Identifier;
-        let exportedLocalNames: Identifier[];
-        let exportedFunctionDeclarations: ExpressionStatement[];
-
+        context.enableSubstitution(SyntaxKind.Identifier); // Substitutes expression identifiers for imported symbols.
+        context.enableSubstitution(SyntaxKind.BinaryExpression); // Substitutes assignments to exported symbols.
+        context.enableSubstitution(SyntaxKind.PrefixUnaryExpression); // Substitutes updates to exported symbols.
+        context.enableSubstitution(SyntaxKind.PostfixUnaryExpression); // Substitutes updates to exported symbols.
+        context.enableEmitNotification(SyntaxKind.SourceFile); // Restore state when substituting nodes in a file.
+
+        const moduleInfoMap = createMap<ExternalModuleInfo>(); // The ExternalModuleInfo for each file.
+        const deferredExports = createMap<Statement[]>(); // Exports to defer until an EndOfDeclarationMarker is found.
+        const exportFunctionsMap = createMap<Identifier>(); // The export function associated with a source file.
+        const noSubstitutionMap = createMap<Map<boolean>>(); // Set of nodes for which substitution rules should be ignored for each file.
+
+        let currentSourceFile: SourceFile; // The current file.
+        let moduleInfo: ExternalModuleInfo; // ExternalModuleInfo for the current file.
+        let exportFunction: Identifier; // The export function for the current file.
+        let contextObject: Identifier; // The context object for the current file.
+        let hoistedStatements: Statement[];
         let enclosingBlockScopedContainer: Node;
-        let currentParent: Node;
-        let currentNode: Node;
+        let noSubstitution: Map<boolean>; // Set of nodes for which substitution rules should be ignored.
 
         return transformSourceFile;
 
+        /**
+         * Transforms the module aspects of a SourceFile.
+         *
+         * @param node The SourceFile node.
+         */
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node)) {
+            if (isDeclarationFile(node)
+                || !(isExternalModule(node)
+                    || compilerOptions.isolatedModules)) {
                 return node;
             }
 
-            if (isExternalModule(node) || compilerOptions.isolatedModules) {
-                currentSourceFile = node;
-                currentNode = node;
-
-                // Perform the transformation.
-                const updated = transformSystemModuleWorker(node);
-                aggregateTransformFlags(updated);
-
-                currentSourceFile = undefined;
-                externalImports = undefined;
-                exportSpecifiers = undefined;
-                exportEquals = undefined;
-                hasExportStarsToExportValues = false;
-                exportFunctionForFile = undefined;
-                contextObjectForFile = undefined;
-                exportedLocalNames = undefined;
-                exportedFunctionDeclarations = undefined;
-                return updated;
-            }
-
-            return node;
-        }
+            const id = getOriginalNodeId(node);
+            currentSourceFile = node;
+            enclosingBlockScopedContainer = node;
 
-        function transformSystemModuleWorker(node: SourceFile) {
             // System modules have the following shape:
             //
             //     System.register(['dep-1', ... 'dep-n'], function(exports) {/* module body function */})
@@ -87,67 +71,103 @@ namespace ts {
             //
             // The only exception in this rule is postfix unary operators,
             // see comment to 'substitutePostfixUnaryExpression' for more details
-            Debug.assert(!exportFunctionForFile);
 
             // Collect information about the external module and dependency groups.
-            ({ externalImports, exportSpecifiers, exportEquals, hasExportStarsToExportValues } = collectExternalModuleInfo(node, resolver));
+            moduleInfo = moduleInfoMap[id] = collectExternalModuleInfo(node, resolver);
 
             // Make sure that the name of the 'exports' function does not conflict with
             // existing identifiers.
-            exportFunctionForFile = createUniqueName("exports");
-            contextObjectForFile = createUniqueName("context");
-
-            exportFunctionForFileMap[getOriginalNodeId(node)] = exportFunctionForFile;
-
-            const dependencyGroups = collectDependencyGroups(externalImports);
-
-            const statements: Statement[] = [];
+            exportFunction = exportFunctionsMap[id] = createUniqueName("exports");
+            contextObject = createUniqueName("context");
 
             // Add the body of the module.
-            addSystemModuleBody(statements, node, dependencyGroups);
-
-            const moduleName = tryGetModuleNameFromFile(node, host, compilerOptions);
-            const dependencies = createArrayLiteral(map(dependencyGroups, getNameOfDependencyGroup));
-            const body = createFunctionExpression(
+            const dependencyGroups = collectDependencyGroups(moduleInfo.externalImports);
+            const moduleBodyFunction = createFunctionExpression(
                 /*modifiers*/ undefined,
                 /*asteriskToken*/ undefined,
                 /*name*/ undefined,
                 /*typeParameters*/ undefined,
                 [
-                    createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, exportFunctionForFile),
-                    createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, contextObjectForFile)
+                    createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, exportFunction),
+                    createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, contextObject)
                 ],
                 /*type*/ undefined,
-                setEmitFlags(
-                    createBlock(statements, /*location*/ undefined, /*multiLine*/ true),
-                    EmitFlags.EmitEmitHelpers
-                )
+                createSystemModuleBody(node, dependencyGroups)
             );
 
             // Write the call to `System.register`
             // Clear the emit-helpers flag for later passes since we'll have already used it in the module body
             // So the helper will be emit at the correct position instead of at the top of the source-file
-            return updateSourceFile(node, [
-                createStatement(
-                    createCall(
-                        createPropertyAccess(createIdentifier("System"), "register"),
-                        /*typeArguments*/ undefined,
-                        moduleName
-                            ? [moduleName, dependencies, body]
-                            : [dependencies, body]
+            const moduleName = tryGetModuleNameFromFile(node, host, compilerOptions);
+            const dependencies = createArrayLiteral(map(dependencyGroups, dependencyGroup => dependencyGroup.name));
+            const updated = updateSourceFileNode(
+                node,
+                createNodeArray([
+                    createStatement(
+                        createCall(
+                            createPropertyAccess(createIdentifier("System"), "register"),
+                            /*typeArguments*/ undefined,
+                            moduleName
+                                ? [moduleName, dependencies, moduleBodyFunction]
+                                : [dependencies, moduleBodyFunction]
+                        )
                     )
-                )
-            ], /*nodeEmitFlags*/ ~EmitFlags.EmitEmitHelpers & getEmitFlags(node));
+                ], node.statements)
+            );
+
+            setEmitFlags(updated, getEmitFlags(node) & ~EmitFlags.EmitEmitHelpers);
+
+            if (noSubstitution) {
+                noSubstitutionMap[id] = noSubstitution;
+                noSubstitution = undefined;
+            }
+
+            currentSourceFile = undefined;
+            moduleInfo = undefined;
+            exportFunction = undefined;
+            contextObject = undefined;
+            hoistedStatements = undefined;
+            enclosingBlockScopedContainer = undefined;
+
+            return aggregateTransformFlags(updated);
+        }
+
+        /**
+         * Collects the dependency groups for this files imports.
+         *
+         * @param externalImports The imports for the file.
+         */
+        function collectDependencyGroups(externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[]) {
+            const groupIndices = createMap<number>();
+            const dependencyGroups: DependencyGroup[] = [];
+            for (let i = 0; i < externalImports.length; i++) {
+                const externalImport = externalImports[i];
+                const externalModuleName = getExternalModuleNameLiteral(externalImport, currentSourceFile, host, resolver, compilerOptions);
+                const text = externalModuleName.text;
+                if (hasProperty(groupIndices, text)) {
+                    // deduplicate/group entries in dependency list by the dependency name
+                    const groupIndex = groupIndices[text];
+                    dependencyGroups[groupIndex].externalImports.push(externalImport);
+                }
+                else {
+                    groupIndices[text] = dependencyGroups.length;
+                    dependencyGroups.push({
+                        name: externalModuleName,
+                        externalImports: [externalImport]
+                    });
+                }
+            }
+
+            return dependencyGroups;
         }
 
         /**
          * Adds the statements for the module body function for the source file.
          *
-         * @param statements The output statements for the module body.
          * @param node The source file for the module.
-         * @param statementOffset The offset at which to begin visiting the statements of the SourceFile.
+         * @param dependencyGroups The grouped dependencies of the module.
          */
-        function addSystemModuleBody(statements: Statement[], node: SourceFile, dependencyGroups: DependencyGroup[]) {
+        function createSystemModuleBody(node: SourceFile, dependencyGroups: DependencyGroup[]) {
             // Shape of the body in system modules:
             //
             //  function (exports) {
@@ -175,10 +195,9 @@ namespace ts {
             // Will be transformed to:
             //
             //  function(exports) {
-            //      var file_1; // local alias
-            //      var y;
             //      function foo() { return y + file_1.x(); }
             //      exports("foo", foo);
+            //      var file_1, y;
             //      return {
             //          setters: [
             //              function(v) { file_1 = v }
@@ -190,13 +209,15 @@ namespace ts {
             //      };
             //  }
 
+            const statements: Statement[] = [];
+
             // We start a new lexical environment in this function body, but *not* in the
             // body of the execute function. This allows us to emit temporary declarations
             // only in the outer module body and not in the inner one.
             startLexicalEnvironment();
 
             // Add any prologue directives.
-            const statementOffset = addPrologueDirectives(statements, node.statements, /*ensureUseStrict*/ !compilerOptions.noImplicitUseStrict, visitSourceElement);
+            const statementOffset = addPrologueDirectives(statements, node.statements, /*ensureUseStrict*/ !compilerOptions.noImplicitUseStrict, sourceElementVisitor);
 
             // var __moduleName = context_1 && context_1.id;
             statements.push(
@@ -207,8 +228,8 @@ namespace ts {
                             "__moduleName",
                             /*type*/ undefined,
                             createLogicalAnd(
-                                contextObjectForFile,
-                                createPropertyAccess(contextObjectForFile, "id")
+                                contextObject,
+                                createPropertyAccess(contextObject, "id")
                             )
                         )
                     ])
@@ -220,27 +241,23 @@ namespace ts {
             // as we both emit transformations as well as aggregate some data used when creating
             // setters. This allows us to reduce the number of times we need to loop through the
             // statements of the source file.
-            const executeStatements = visitNodes(node.statements, visitSourceElement, isStatement, statementOffset);
+            const executeStatements = visitNodes(node.statements, sourceElementVisitor, isStatement, statementOffset);
+
+            // Emit early exports for function declarations.
+            addRange(statements, hoistedStatements);
 
-            // We emit the lexical environment (hoisted variables and function declarations)
-            // early to align roughly with our previous emit output.
+            // We emit hoisted variables early to align roughly with our previous emit output.
             // Two key differences in this approach are:
             // - Temporary variables will appear at the top rather than at the bottom of the file
-            // - Calls to the exporter for exported function declarations are grouped after
-            //   the declarations.
             addRange(statements, endLexicalEnvironment());
 
-            // Emit early exports for function declarations.
-            addRange(statements, exportedFunctionDeclarations);
-
             const exportStarFunction = addExportStarIfNeeded(statements);
-
             statements.push(
                 createReturn(
                     setMultiLine(
                         createObjectLiteral([
                             createPropertyAssignment("setters",
-                                generateSetters(exportStarFunction, dependencyGroups)
+                                createSettersArray(exportStarFunction, dependencyGroups)
                             ),
                             createPropertyAssignment("execute",
                                 createFunctionExpression(
@@ -262,24 +279,34 @@ namespace ts {
                     )
                 )
             );
+
+            const body = createBlock(statements, /*location*/ undefined, /*multiLine*/ true);
+            setEmitFlags(body, EmitFlags.EmitEmitHelpers);
+            return body;
         }
 
+        /**
+         * Adds an exportStar function to a statement list if it is needed for the file.
+         *
+         * @param statements A statement list.
+         */
         function addExportStarIfNeeded(statements: Statement[]) {
-            if (!hasExportStarsToExportValues) {
+            if (!moduleInfo.hasExportStarsToExportValues) {
                 return;
             }
+
             // when resolving exports local exported entries/indirect exported entries in the module
             // should always win over entries with similar names that were added via star exports
             // to support this we store names of local/indirect exported entries in a set.
             // this set is used to filter names brought by star expors.
 
             // local names set should only be added if we have anything exported
-            if (!exportedLocalNames && isEmpty(exportSpecifiers)) {
+            if (!moduleInfo.exportedNames && isEmpty(moduleInfo.exportSpecifiers)) {
                 // no exported declarations (export var ...) or export specifiers (export {x})
                 // check if we have any non star export declarations.
                 let hasExportDeclarationWithExportClause = false;
-                for (const externalImport of externalImports) {
-                    if (externalImport.kind === SyntaxKind.ExportDeclaration && (<ExportDeclaration>externalImport).exportClause) {
+                for (const externalImport of moduleInfo.externalImports) {
+                    if (externalImport.kind === SyntaxKind.ExportDeclaration && externalImport.exportClause) {
                         hasExportDeclarationWithExportClause = true;
                         break;
                     }
@@ -287,24 +314,30 @@ namespace ts {
 
                 if (!hasExportDeclarationWithExportClause) {
                     // we still need to emit exportStar helper
-                    return addExportStarFunction(statements, /*localNames*/ undefined);
+                    const exportStarFunction = createExportStarFunction(/*localNames*/ undefined);
+                    statements.push(exportStarFunction);
+                    return exportStarFunction.name;
                 }
             }
 
             const exportedNames: ObjectLiteralElementLike[] = [];
-            if (exportedLocalNames) {
-                for (const exportedLocalName of exportedLocalNames) {
+            if (moduleInfo.exportedNames) {
+                for (const exportedLocalName of moduleInfo.exportedNames) {
+                    if (exportedLocalName.text === "default") {
+                        continue;
+                    }
+
                     // write name of exported declaration, i.e 'export var x...'
                     exportedNames.push(
                         createPropertyAssignment(
-                            createLiteral(exportedLocalName.text),
+                            createLiteral(exportedLocalName),
                             createLiteral(true)
                         )
                     );
                 }
             }
 
-            for (const externalImport of externalImports) {
+            for (const externalImport of moduleInfo.externalImports) {
                 if (externalImport.kind !== SyntaxKind.ExportDeclaration) {
                     continue;
                 }
@@ -340,14 +373,90 @@ namespace ts {
                 )
             );
 
-            return addExportStarFunction(statements, exportedNamesStorageRef);
+            const exportStarFunction = createExportStarFunction(exportedNamesStorageRef);
+            statements.push(exportStarFunction);
+            return exportStarFunction.name;
+        }
+
+        /**
+         * Creates an exportStar function for the file, with an optional set of excluded local
+         * names.
+         *
+         * @param localNames An optional reference to an object containing a set of excluded local
+         * names.
+         */
+        function createExportStarFunction(localNames: Identifier | undefined) {
+            const exportStarFunction = createUniqueName("exportStar");
+            const m = createIdentifier("m");
+            const n = createIdentifier("n");
+            const exports = createIdentifier("exports");
+            let condition: Expression = createStrictInequality(n, createLiteral("default"));
+            if (localNames) {
+                condition = createLogicalAnd(
+                    condition,
+                    createLogicalNot(createHasOwnProperty(localNames, n))
+                );
+            }
+
+            return createFunctionDeclaration(
+                /*decorators*/ undefined,
+                /*modifiers*/ undefined,
+                /*asteriskToken*/ undefined,
+                exportStarFunction,
+                /*typeParameters*/ undefined,
+                [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, m)],
+                /*type*/ undefined,
+                createBlock([
+                    createVariableStatement(
+                        /*modifiers*/ undefined,
+                        createVariableDeclarationList([
+                            createVariableDeclaration(
+                                exports,
+                                /*type*/ undefined,
+                                createObjectLiteral([])
+                            )
+                        ])
+                    ),
+                    createForIn(
+                        createVariableDeclarationList([
+                            createVariableDeclaration(n, /*type*/ undefined)
+                        ]),
+                        m,
+                        createBlock([
+                            setEmitFlags(
+                                createIf(
+                                    condition,
+                                    createStatement(
+                                        createAssignment(
+                                            createElementAccess(exports, n),
+                                            createElementAccess(m, n)
+                                        )
+                                    )
+                                ),
+                                EmitFlags.SingleLine
+                            )
+                        ])
+                    ),
+                    createStatement(
+                        createCall(
+                            exportFunction,
+                            /*typeArguments*/ undefined,
+                            [exports]
+                        )
+                    )
+                ],
+                /*location*/ undefined,
+                /*multiline*/ true)
+            );
         }
 
         /**
-         * Emits a setter callback for each dependency group.
-         * @param write The callback used to write each callback.
+         * Creates an array setter callbacks for each dependency group.
+         *
+         * @param exportStarFunction A reference to an exportStarFunction for the file.
+         * @param dependencyGroups An array of grouped dependencies.
          */
-        function generateSetters(exportStarFunction: Identifier, dependencyGroups: DependencyGroup[]) {
+        function createSettersArray(exportStarFunction: Identifier, dependencyGroups: DependencyGroup[]) {
             const setters: Expression[] = [];
             for (const group of dependencyGroups) {
                 // derive a unique name for parameter from the first named entry in the group
@@ -402,7 +511,7 @@ namespace ts {
                                 statements.push(
                                     createStatement(
                                         createCall(
-                                            exportFunctionForFile,
+                                            exportFunction,
                                             /*typeArguments*/ undefined,
                                             [createObjectLiteral(properties, /*location*/ undefined, /*multiline*/ true)]
                                         )
@@ -445,7 +554,16 @@ namespace ts {
             return createArrayLiteral(setters, /*location*/ undefined, /*multiLine*/ true);
         }
 
-        function visitSourceElement(node: Node): VisitResult<Node> {
+        //
+        // Top-level Source Element Visitors
+        //
+
+        /**
+         * Visit source elements at the top-level of a module.
+         *
+         * @param node The node to visit.
+         */
+        function sourceElementVisitor(node: Node): VisitResult<Node> {
             switch (node.kind) {
                 case SyntaxKind.ImportDeclaration:
                     return visitImportDeclaration(<ImportDeclaration>node);
@@ -460,260 +578,137 @@ namespace ts {
                     return visitExportAssignment(<ExportAssignment>node);
 
                 default:
-                    return visitNestedNode(node);
+                    return nestedElementVisitor(node);
             }
         }
 
-        function visitNestedNode(node: Node): VisitResult<Node> {
-            const savedEnclosingBlockScopedContainer = enclosingBlockScopedContainer;
-            const savedCurrentParent = currentParent;
-            const savedCurrentNode = currentNode;
-
-            const currentGrandparent = currentParent;
-            currentParent = currentNode;
-            currentNode = node;
-
-            if (currentParent && isBlockScope(currentParent, currentGrandparent)) {
-                enclosingBlockScopedContainer = currentParent;
+        /**
+         * Visits an ImportDeclaration node.
+         *
+         * @param node The node to visit.
+         */
+        function visitImportDeclaration(node: ImportDeclaration): VisitResult<Statement> {
+            let statements: Statement[];
+            if (node.importClause) {
+                hoistVariableDeclaration(getLocalNameForExternalImport(node, currentSourceFile));
             }
 
-            const result = visitNestedNodeWorker(node);
-
-            enclosingBlockScopedContainer = savedEnclosingBlockScopedContainer;
-            currentParent = savedCurrentParent;
-            currentNode = savedCurrentNode;
-
-            return result;
-        }
-
-        function visitNestedNodeWorker(node: Node): VisitResult<Node> {
-            switch (node.kind) {
-                case SyntaxKind.VariableStatement:
-                    return visitVariableStatement(<VariableStatement>node);
-
-                case SyntaxKind.FunctionDeclaration:
-                    return visitFunctionDeclaration(<FunctionDeclaration>node);
-
-                case SyntaxKind.ClassDeclaration:
-                    return visitClassDeclaration(<ClassDeclaration>node);
-
-                case SyntaxKind.ForStatement:
-                    return visitForStatement(<ForStatement>node);
-
-                case SyntaxKind.ForInStatement:
-                    return visitForInStatement(<ForInStatement>node);
-
-                case SyntaxKind.ForOfStatement:
-                    return visitForOfStatement(<ForOfStatement>node);
-
-                case SyntaxKind.DoStatement:
-                    return visitDoStatement(<DoStatement>node);
-
-                case SyntaxKind.WhileStatement:
-                    return visitWhileStatement(<WhileStatement>node);
-
-                case SyntaxKind.LabeledStatement:
-                    return visitLabeledStatement(<LabeledStatement>node);
-
-                case SyntaxKind.WithStatement:
-                    return visitWithStatement(<WithStatement>node);
-
-                case SyntaxKind.SwitchStatement:
-                    return visitSwitchStatement(<SwitchStatement>node);
-
-                case SyntaxKind.CaseBlock:
-                    return visitCaseBlock(<CaseBlock>node);
-
-                case SyntaxKind.CaseClause:
-                    return visitCaseClause(<CaseClause>node);
-
-                case SyntaxKind.DefaultClause:
-                    return visitDefaultClause(<DefaultClause>node);
-
-                case SyntaxKind.TryStatement:
-                    return visitTryStatement(<TryStatement>node);
-
-                case SyntaxKind.CatchClause:
-                    return visitCatchClause(<CatchClause>node);
-
-                case SyntaxKind.Block:
-                    return visitBlock(<Block>node);
-
-                case SyntaxKind.ExpressionStatement:
-                    return visitExpressionStatement(<ExpressionStatement>node);
-
-                default:
-                    return node;
+            if (hasAssociatedEndOfDeclarationMarker(node)) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportsOfImportDeclaration(deferredExports[id], node);
             }
-        }
-
-        function visitImportDeclaration(node: ImportDeclaration): Node {
-            if (node.importClause && contains(externalImports, node)) {
-                hoistVariableDeclaration(getLocalNameForExternalImport(node, currentSourceFile));
+            else {
+                statements = appendExportsOfImportDeclaration(statements, node);
             }
 
-            return undefined;
+            return singleOrMany(statements);
         }
 
-        function visitImportEqualsDeclaration(node: ImportEqualsDeclaration): Node {
-            if (contains(externalImports, node)) {
-                hoistVariableDeclaration(getLocalNameForExternalImport(node, currentSourceFile));
-            }
+        /**
+         * Visits an ImportEqualsDeclaration node.
+         *
+         * @param node The node to visit.
+         */
+        function visitImportEqualsDeclaration(node: ImportEqualsDeclaration): VisitResult<Statement> {
+            Debug.assert(isExternalModuleImportEqualsDeclaration(node), "import= for internal module references should be handled in an earlier transformer.");
 
-            // NOTE(rbuckton): Do we support export import = require('') in System?
-            return undefined;
-        }
+            let statements: Statement[];
+            hoistVariableDeclaration(getLocalNameForExternalImport(node, currentSourceFile));
 
-        function visitExportDeclaration(node: ExportDeclaration): VisitResult<Statement> {
-            if (!node.moduleSpecifier) {
-                const statements: Statement[] = [];
-                addRange(statements, map(node.exportClause.elements, visitExportSpecifier));
-                return statements;
+            if (hasAssociatedEndOfDeclarationMarker(node)) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportsOfImportEqualsDeclaration(deferredExports[id], node);
             }
-
-            return undefined;
-        }
-
-        function visitExportSpecifier(specifier: ExportSpecifier): Statement {
-            recordExportName(specifier.name);
-            return createExportStatement(
-                specifier.name,
-                specifier.propertyName || specifier.name
-            );
-        }
-
-        function visitExportAssignment(node: ExportAssignment): Statement {
-            if (node.isExportEquals) {
-                // Elide `export=` as it is illegal in a SystemJS module.
-                return undefined;
+            else {
+                statements = appendExportsOfImportEqualsDeclaration(statements, node);
             }
 
-            return createExportStatement(
-                createLiteral("default"),
-                node.expression
-            );
+            return singleOrMany(statements);
         }
 
         /**
-         * Visits a variable statement, hoisting declared names to the top-level module body.
-         * Each declaration is rewritten into an assignment expression.
+         * Visits an ExportDeclaration node. ExportDeclarations are elided as they are handled via
+         * `appendExportsOfDeclaration`.
          *
-         * @param node The variable statement to visit.
+         * @param The node to visit.
          */
-        function visitVariableStatement(node: VariableStatement): VisitResult<Statement> {
-            // hoist only non-block scoped declarations or block scoped declarations parented by source file
-            const shouldHoist =
-                ((getCombinedNodeFlags(getOriginalNode(node.declarationList)) & NodeFlags.BlockScoped) == 0) ||
-                enclosingBlockScopedContainer.kind === SyntaxKind.SourceFile;
-            if (!shouldHoist) {
-                return node;
-            }
-            const isExported = hasModifier(node, ModifierFlags.Export);
-            const expressions: Expression[] = [];
-            for (const variable of node.declarationList.declarations) {
-                const visited = <Expression>transformVariable(variable, isExported);
-                if (visited) {
-                    expressions.push(visited);
-                }
-            }
-
-            if (expressions.length) {
-                return createStatement(inlineExpressions(expressions), node);
-            }
-
+        function visitExportDeclaration(node: ExportDeclaration): VisitResult<Statement> {
             return undefined;
         }
 
         /**
-         * Transforms a VariableDeclaration into one or more assignment expressions.
+         * Visits an ExportAssignment node.
          *
-         * @param node The VariableDeclaration to transform.
-         * @param isExported A value used to indicate whether the containing statement was exported.
+         * @param node The node to visit.
          */
-        function transformVariable(node: VariableDeclaration, isExported: boolean): VariableDeclaration | Expression {
-            // Hoist any bound names within the declaration.
-            hoistBindingElement(node, isExported);
-
-            if (!node.initializer) {
-                // If the variable has no initializer, ignore it.
-                return;
+        function visitExportAssignment(node: ExportAssignment): VisitResult<Statement> {
+            if (node.isExportEquals) {
+                // Elide `export=` as it is illegal in a SystemJS module.
+                return undefined;
             }
 
-            const name = node.name;
-            if (isIdentifier(name)) {
-                // If the variable has an IdentifierName, write out an assignment expression in its place.
-                return createAssignment(name, node.initializer);
+            const expression = visitNode(node.expression, destructuringVisitor, isExpression);
+            const original = node.original;
+            if (original && hasAssociatedEndOfDeclarationMarker(original)) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportStatement(deferredExports[id], createIdentifier("default"), expression, /*allowComments*/ true);
             }
             else {
-                // If the variable has a BindingPattern, flatten the variable into multiple assignment expressions.
-                return flattenVariableDestructuringToExpression(context, node, hoistVariableDeclaration);
+                return createExportStatement(createIdentifier("default"), expression, /*allowComments*/ true);
             }
         }
 
         /**
          * Visits a FunctionDeclaration, hoisting it to the outer module body function.
          *
-         * @param node The function declaration to visit.
+         * @param node The node to visit.
          */
-        function visitFunctionDeclaration(node: FunctionDeclaration): Node {
+        function visitFunctionDeclaration(node: FunctionDeclaration): VisitResult<Statement> {
             if (hasModifier(node, ModifierFlags.Export)) {
-                // If the function is exported, ensure it has a name and rewrite the function without any export flags.
-                const name = node.name || getGeneratedNameForNode(node);
-                // Keep async modifier for ES2017 transformer
-                const isAsync = hasModifier(node, ModifierFlags.Async);
-                const newNode = createFunctionDeclaration(
-                    /*decorators*/ undefined,
-                    isAsync ? [<Modifier>createNode(SyntaxKind.AsyncKeyword)] : undefined,
-                    node.asteriskToken,
-                    name,
-                    /*typeParameters*/ undefined,
-                    node.parameters,
-                    /*type*/ undefined,
-                    node.body,
-                    /*location*/ node);
-
-                // Record a declaration export in the outer module body function.
-                recordExportedFunctionDeclaration(node);
-
-                if (!hasModifier(node, ModifierFlags.Default)) {
-                    recordExportName(name);
-                }
+                hoistedStatements = append(hoistedStatements,
+                    updateFunctionDeclaration(
+                        node,
+                        node.decorators,
+                        visitNodes(node.modifiers, modifierVisitor, isModifier),
+                        getDeclarationName(node, /*allowComments*/ true, /*allowSourceMaps*/ true),
+                        /*typeParameters*/ undefined,
+                        visitNodes(node.parameters, destructuringVisitor, isParameterDeclaration),
+                        /*type*/ undefined,
+                        visitNode(node.body, destructuringVisitor, isBlock)));
+            }
+            else {
+                hoistedStatements = append(hoistedStatements, node);
+            }
 
-                setOriginalNode(newNode, node);
-                node = newNode;
+            if (hasAssociatedEndOfDeclarationMarker(node)) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportsOfHoistedDeclaration(deferredExports[id], node);
+            }
+            else {
+                hoistedStatements = appendExportsOfHoistedDeclaration(hoistedStatements, node);
             }
 
-            // Hoist the function declaration to the outer module body function.
-            hoistFunctionDeclaration(node);
             return undefined;
         }
 
-        function visitExpressionStatement(node: ExpressionStatement): VisitResult<Statement> {
-            const originalNode = getOriginalNode(node);
-            if ((originalNode.kind === SyntaxKind.ModuleDeclaration || originalNode.kind === SyntaxKind.EnumDeclaration) && hasModifier(originalNode, ModifierFlags.Export)) {
-                const name = getDeclarationName(<ModuleDeclaration | EnumDeclaration>originalNode);
-                return [
-                    node,
-                    createExportStatement(name, name)
-                ];
-            }
-            return node;
-        }
-
         /**
          * Visits a ClassDeclaration, hoisting its name to the outer module body function.
          *
-         * @param node The class declaration to visit.
+         * @param node The node to visit.
          */
         function visitClassDeclaration(node: ClassDeclaration): VisitResult<Statement> {
+            let statements: Statement[];
+
             // Hoist the name of the class declaration to the outer module body function.
-            const name = getDeclarationName(node);
+            const name = getLocalName(node);
             hoistVariableDeclaration(name);
 
-            const statements: Statement[] = [];
-
             // Rewrite the class declaration into an assignment of a class expression.
-            statements.push(
+            statements = append(statements,
                 createStatement(
                     createAssignment(
                         name,
@@ -721,8 +716,8 @@ namespace ts {
                             /*modifiers*/ undefined,
                             node.name,
                             /*typeParameters*/ undefined,
-                            node.heritageClauses,
-                            node.members,
+                            visitNodes(node.heritageClauses, destructuringVisitor, isHeritageClause),
+                            visitNodes(node.members, destructuringVisitor, isClassElement),
                             /*location*/ node
                         )
                     ),
@@ -730,651 +725,1039 @@ namespace ts {
                 )
             );
 
-            // If the class was exported, write a declaration export to the inner module body function.
-            if (hasModifier(node, ModifierFlags.Export)) {
-                if (!hasModifier(node, ModifierFlags.Default)) {
-                    recordExportName(name);
-                }
-
-                statements.push(createDeclarationExport(node));
+            if (hasAssociatedEndOfDeclarationMarker(node)) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportsOfHoistedDeclaration(deferredExports[id], node);
+            }
+            else {
+                statements = appendExportsOfHoistedDeclaration(statements, node);
             }
 
-            return statements;
-        }
-
-        function shouldHoistLoopInitializer(node: VariableDeclarationList | Expression) {
-            return isVariableDeclarationList(node) && (getCombinedNodeFlags(node) & NodeFlags.BlockScoped) === 0;
+            return singleOrMany(statements);
         }
 
         /**
-         * Visits the body of a ForStatement to hoist declarations.
+         * Visits a variable statement, hoisting declared names to the top-level module body.
+         * Each declaration is rewritten into an assignment expression.
          *
-         * @param node The statement to visit.
+         * @param node The node to visit.
          */
-        function visitForStatement(node: ForStatement): ForStatement {
-            const initializer = node.initializer;
-            if (shouldHoistLoopInitializer(initializer)) {
-                const expressions: Expression[] = [];
-                for (const variable of (<VariableDeclarationList>initializer).declarations) {
-                    const visited = <Expression>transformVariable(variable, /*isExported*/ false);
-                    if (visited) {
-                        expressions.push(visited);
-                    }
-                };
-
-                return createFor(
-                    expressions.length
-                        ? inlineExpressions(expressions)
-                        : createOmittedExpression(),
-                    node.condition,
-                    node.incrementor,
-                    visitNode(node.statement, visitNestedNode, isStatement),
-                    /*location*/ node
-                );
+        function visitVariableStatement(node: VariableStatement): VisitResult<Statement> {
+            if (!shouldHoistVariableDeclarationList(node.declarationList)) {
+                return visitNode(node, destructuringVisitor, isStatement);
             }
-            else {
-                return visitEachChild(node, visitNestedNode, context);
+
+            let expressions: Expression[];
+            const isExportedDeclaration = hasModifier(node, ModifierFlags.Export);
+            const isMarkedDeclaration = hasAssociatedEndOfDeclarationMarker(node);
+            for (const variable of node.declarationList.declarations) {
+                if (variable.initializer) {
+                    expressions = append(expressions, transformInitializedVariable(variable, isExportedDeclaration && !isMarkedDeclaration));
+                }
+                else {
+                    hoistBindingElement(variable);
+                }
             }
-        }
 
-        /**
-         * Transforms and hoists the declaration list of a ForInStatement or ForOfStatement into an expression.
-         *
-         * @param node The decalaration list to transform.
-         */
-        function transformForBinding(node: VariableDeclarationList): Expression {
-            const firstDeclaration = firstOrUndefined(node.declarations);
-            hoistBindingElement(firstDeclaration, /*isExported*/ false);
-
-            const name = firstDeclaration.name;
-            return isIdentifier(name)
-                ? name
-                : flattenVariableDestructuringToExpression(context, firstDeclaration, hoistVariableDeclaration);
-        }
+            let statements: Statement[];
+            if (expressions) {
+                statements = append(statements, createStatement(inlineExpressions(expressions), /*location*/ node));
+            }
 
-        /**
-         * Visits the body of a ForInStatement to hoist declarations.
-         *
-         * @param node The statement to visit.
-         */
-        function visitForInStatement(node: ForInStatement): ForInStatement {
-            const initializer = node.initializer;
-            if (shouldHoistLoopInitializer(initializer)) {
-                return updateForIn(
-                    node,
-                    transformForBinding(<VariableDeclarationList>initializer),
-                    node.expression,
-                    visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock)
-                );
+            if (isMarkedDeclaration) {
+                // Defer exports until we encounter an EndOfDeclarationMarker node
+                const id = getOriginalNodeId(node);
+                deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], node, isExportedDeclaration);
             }
             else {
-                return visitEachChild(node, visitNestedNode, context);
+                statements = appendExportsOfVariableStatement(statements, node, /*exportSelf*/ false);
             }
+
+            return singleOrMany(statements);
         }
 
         /**
-         * Visits the body of a ForOfStatement to hoist declarations.
+         * Hoists the declared names of a VariableDeclaration or BindingElement.
          *
-         * @param node The statement to visit.
+         * @param node The declaration to hoist.
          */
-        function visitForOfStatement(node: ForOfStatement): ForOfStatement {
-            const initializer = node.initializer;
-            if (shouldHoistLoopInitializer(initializer)) {
-                return updateForOf(
-                    node,
-                    transformForBinding(<VariableDeclarationList>initializer),
-                    node.expression,
-                    visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock)
-                );
+        function hoistBindingElement(node: VariableDeclaration | BindingElement): void {
+            if (isBindingPattern(node.name)) {
+                for (const element of node.name.elements) {
+                    if (!isOmittedExpression(element)) {
+                        hoistBindingElement(element);
+                    }
+                }
             }
             else {
-                return visitEachChild(node, visitNestedNode, context);
+                hoistVariableDeclaration(getSynthesizedClone(node.name));
             }
         }
 
         /**
-         * Visits the body of a DoStatement to hoist declarations.
+         * Determines whether a VariableDeclarationList should be hoisted.
          *
-         * @param node The statement to visit.
+         * @param node The node to test.
          */
-        function visitDoStatement(node: DoStatement) {
-            return updateDo(
-                node,
-                visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock),
-                node.expression
-            );
+        function shouldHoistVariableDeclarationList(node: VariableDeclarationList) {
+            // hoist only non-block scoped declarations or block scoped declarations parented by source file
+            return (getEmitFlags(node) & EmitFlags.NoHoisting) === 0
+                && (enclosingBlockScopedContainer.kind === SyntaxKind.SourceFile
+                    || (getOriginalNode(node).flags & NodeFlags.BlockScoped) === 0);
         }
 
         /**
-         * Visits the body of a WhileStatement to hoist declarations.
+         * Transform an initialized variable declaration into an expression.
          *
-         * @param node The statement to visit.
+         * @param node The node to transform.
+         * @param isExportedDeclaration A value indicating whether the variable is exported.
          */
-        function visitWhileStatement(node: WhileStatement) {
-            return updateWhile(
-                node,
-                node.expression,
-                visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock)
-            );
+        function transformInitializedVariable(node: VariableDeclaration, isExportedDeclaration: boolean): Expression {
+            const createAssignment = isExportedDeclaration ? createExportedVariableAssignment : createNonExportedVariableAssignment;
+            return isBindingPattern(node.name)
+                ? flattenVariableDestructuringToExpression(context, node, hoistVariableDeclaration, createAssignment, destructuringVisitor)
+                : createAssignment(node.name, visitNode(node.initializer, destructuringVisitor, isExpression));
         }
 
         /**
-         * Visits the body of a LabeledStatement to hoist declarations.
+         * Creates an assignment expression for an exported variable declaration.
          *
-         * @param node The statement to visit.
+         * @param name The name of the variable.
+         * @param value The value of the variable's initializer.
+         * @param location The source map location for the assignment.
          */
-        function visitLabeledStatement(node: LabeledStatement) {
-            return updateLabel(
-                node,
-                node.label,
-                visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock)
-            );
+        function createExportedVariableAssignment(name: Identifier, value: Expression, location?: TextRange) {
+            return createVariableAssignment(name, value, location, /*isExportedDeclaration*/ true);
         }
 
         /**
-         * Visits the body of a WithStatement to hoist declarations.
+         * Creates an assignment expression for a non-exported variable declaration.
          *
-         * @param node The statement to visit.
+         * @param name The name of the variable.
+         * @param value The value of the variable's initializer.
+         * @param location The source map location for the assignment.
          */
-        function visitWithStatement(node: WithStatement) {
-            return updateWith(
-                node,
-                node.expression,
-                visitNode(node.statement, visitNestedNode, isStatement, /*optional*/ false, liftToBlock)
-            );
+        function createNonExportedVariableAssignment(name: Identifier, value: Expression, location?: TextRange) {
+            return createVariableAssignment(name, value, location, /*isExportedDeclaration*/ false);
         }
 
         /**
-         * Visits the body of a SwitchStatement to hoist declarations.
+         * Creates an assignment expression for a variable declaration.
          *
-         * @param node The statement to visit.
+         * @param name The name of the variable.
+         * @param value The value of the variable's initializer.
+         * @param location The source map location for the assignment.
+         * @param isExportedDeclaration A value indicating whether the variable is exported.
          */
-        function visitSwitchStatement(node: SwitchStatement) {
-            return updateSwitch(
-                node,
-                node.expression,
-                visitNode(node.caseBlock, visitNestedNode, isCaseBlock)
-            );
+        function createVariableAssignment(name: Identifier, value: Expression, location: TextRange, isExportedDeclaration: boolean) {
+            hoistVariableDeclaration(getSynthesizedClone(name));
+            return isExportedDeclaration
+                ? createExportExpression(name, preventSubstitution(createAssignment(name, value, location)))
+                : preventSubstitution(createAssignment(name, value, location));
         }
 
         /**
-         * Visits the body of a CaseBlock to hoist declarations.
+         * Visits a MergeDeclarationMarker used as a placeholder for the beginning of a merged
+         * and transformed declaration.
          *
          * @param node The node to visit.
          */
-        function visitCaseBlock(node: CaseBlock) {
-            return updateCaseBlock(
-                node,
-                visitNodes(node.clauses, visitNestedNode, isCaseOrDefaultClause)
-            );
-        }
+        function visitMergeDeclarationMarker(node: MergeDeclarationMarker): VisitResult<Statement> {
+            // For an EnumDeclaration or ModuleDeclaration that merges with a preceeding
+            // declaration we do not emit a leading variable declaration. To preserve the
+            // begin/end semantics of the declararation and to properly handle exports
+            // we wrapped the leading variable declaration in a `MergeDeclarationMarker`.
+            //
+            // To balance the declaration, we defer the exports of the elided variable
+            // statement until we visit this declaration's `EndOfDeclarationMarker`.
+            if (hasAssociatedEndOfDeclarationMarker(node) && node.original.kind === SyntaxKind.VariableStatement) {
+                const id = getOriginalNodeId(node);
+                const isExportedDeclaration = hasModifier(node.original, ModifierFlags.Export);
+                deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], <VariableStatement>node.original, isExportedDeclaration);
+            }
 
-        /**
-         * Visits the body of a CaseClause to hoist declarations.
-         *
-         * @param node The clause to visit.
-         */
-        function visitCaseClause(node: CaseClause) {
-            return updateCaseClause(
-                node,
-                node.expression,
-                visitNodes(node.statements, visitNestedNode, isStatement)
-            );
+            return node;
         }
 
         /**
-         * Visits the body of a DefaultClause to hoist declarations.
+         * Determines whether a node has an associated EndOfDeclarationMarker.
          *
-         * @param node The clause to visit.
+         * @param node The node to test.
          */
-        function visitDefaultClause(node: DefaultClause) {
-            return visitEachChild(node, visitNestedNode, context);
+        function hasAssociatedEndOfDeclarationMarker(node: Node) {
+            return (getEmitFlags(node) & EmitFlags.HasEndOfDeclarationMarker) !== 0;
         }
 
         /**
-         * Visits the body of a TryStatement to hoist declarations.
+         * Visits a DeclarationMarker used as a placeholder for the end of a transformed
+         * declaration.
          *
-         * @param node The statement to visit.
+         * @param node The node to visit.
          */
-        function visitTryStatement(node: TryStatement) {
-            return visitEachChild(node, visitNestedNode, context);
-        }
+        function visitEndOfDeclarationMarker(node: EndOfDeclarationMarker): VisitResult<Statement> {
+            // For some transformations we emit an `EndOfDeclarationMarker` to mark the actual
+            // end of the transformed declaration. We use this marker to emit any deferred exports
+            // of the declaration.
+            const id = getOriginalNodeId(node);
+            const statements = deferredExports[id];
+            if (statements) {
+                delete deferredExports[id];
+                return append(statements, node);
+            }
 
-        /**
-         * Visits the body of a CatchClause to hoist declarations.
-         *
-         * @param node The clause to visit.
-         */
-        function visitCatchClause(node: CatchClause) {
-            return updateCatchClause(
-                node,
-                node.variableDeclaration,
-                visitNode(node.block, visitNestedNode, isBlock)
-            );
+            return node;
         }
 
         /**
-         * Visits the body of a Block to hoist declarations.
+         * Appends the exports of an ImportDeclaration to a statement list, returning the
+         * statement list.
          *
-         * @param node The block to visit.
+         * @param statements A statement list to which the down-level export statements are to be
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
+         * @param decl The declaration whose exports are to be recorded.
          */
-        function visitBlock(node: Block) {
-            return visitEachChild(node, visitNestedNode, context);
-        }
+        function appendExportsOfImportDeclaration(statements: Statement[], decl: ImportDeclaration) {
+            if (moduleInfo.exportEquals) {
+                return statements;
+            }
 
-        //
-        // Substitutions
-        //
+            const importClause = decl.importClause;
+            if (!importClause) {
+                return statements;
+            }
 
-        function onEmitNode(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void {
-            if (node.kind === SyntaxKind.SourceFile) {
-                exportFunctionForFile = exportFunctionForFileMap[getOriginalNodeId(node)];
-                previousOnEmitNode(emitContext, node, emitCallback);
-                exportFunctionForFile = undefined;
+            if (importClause.name) {
+                statements = appendExportsOfDeclaration(statements, importClause);
             }
-            else {
-                previousOnEmitNode(emitContext, node, emitCallback);
+
+            const namedBindings = importClause.namedBindings;
+            if (namedBindings) {
+                switch (namedBindings.kind) {
+                    case SyntaxKind.NamespaceImport:
+                        statements = appendExportsOfDeclaration(statements, namedBindings);
+                        break;
+
+                    case SyntaxKind.NamedImports:
+                        for (const importBinding of namedBindings.elements) {
+                            statements = appendExportsOfDeclaration(statements, importBinding);
+                        }
+
+                        break;
+                }
             }
+
+            return statements;
         }
 
         /**
-         * Hooks node substitutions.
+         * Appends the export of an ImportEqualsDeclaration to a statement list, returning the
+         * statement list.
          *
-         * @param node The node to substitute.
-         * @param isExpression A value indicating whether the node is to be used in an expression
-         *                     position.
+         * @param statements A statement list to which the down-level export statements are to be
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
+         * @param decl The declaration whose exports are to be recorded.
          */
-        function onSubstituteNode(emitContext: EmitContext, node: Node) {
-            node = previousOnSubstituteNode(emitContext, node);
-            if (emitContext === EmitContext.Expression) {
-                return substituteExpression(<Expression>node);
+        function appendExportsOfImportEqualsDeclaration(statements: Statement[], decl: ImportEqualsDeclaration): Statement[] | undefined {
+            if (moduleInfo.exportEquals) {
+                return statements;
             }
 
-            return node;
+            return appendExportsOfDeclaration(statements, decl);
         }
 
         /**
-         * Substitute the expression, if necessary.
+         * Appends the exports of a VariableStatement to a statement list, returning the statement
+         * list.
          *
-         * @param node The node to substitute.
+         * @param statements A statement list to which the down-level export statements are to be
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
+         * @param node The VariableStatement whose exports are to be recorded.
+         * @param exportSelf A value indicating whether to also export each VariableDeclaration of
+         * `nodes` declaration list.
          */
-        function substituteExpression(node: Expression) {
-            switch (node.kind) {
-                case SyntaxKind.Identifier:
-                    return substituteExpressionIdentifier(<Identifier>node);
-                case SyntaxKind.BinaryExpression:
-                    return substituteBinaryExpression(<BinaryExpression>node);
-                case SyntaxKind.PrefixUnaryExpression:
-                case SyntaxKind.PostfixUnaryExpression:
-                    return substituteUnaryExpression(<PrefixUnaryExpression | PostfixUnaryExpression>node);
+        function appendExportsOfVariableStatement(statements: Statement[] | undefined, node: VariableStatement, exportSelf: boolean): Statement[] | undefined {
+            if (moduleInfo.exportEquals) {
+                return statements;
             }
-            return node;
-        }
 
-        /**
-         * Substitution for identifiers exported at the top level of a module.
-         */
-        function substituteExpressionIdentifier(node: Identifier): Expression {
-            const importDeclaration = resolver.getReferencedImportDeclaration(node);
-            if (importDeclaration) {
-                const importBinding = createImportBinding(importDeclaration);
-                if (importBinding) {
-                    return importBinding;
+            for (const decl of node.declarationList.declarations) {
+                if (decl.initializer || exportSelf) {
+                    statements = appendExportsOfBindingElement(statements, decl, exportSelf);
                 }
             }
 
-            return node;
+            return statements;
         }
 
-        function substituteBinaryExpression(node: BinaryExpression): Expression {
-            if (isAssignmentOperator(node.operatorToken.kind)) {
-                return substituteAssignmentExpression(node);
+        /**
+         * Appends the exports of a VariableDeclaration or BindingElement to a statement list,
+         * returning the statement list.
+         *
+         * @param statements A statement list to which the down-level export statements are to be
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
+         * @param decl The declaration whose exports are to be recorded.
+         * @param exportSelf A value indicating whether to also export the declaration itself.
+         */
+        function appendExportsOfBindingElement(statements: Statement[] | undefined, decl: VariableDeclaration | BindingElement, exportSelf: boolean): Statement[] | undefined {
+            if (moduleInfo.exportEquals) {
+                return statements;
             }
 
-            return node;
-        }
-
-        function substituteAssignmentExpression(node: BinaryExpression): Expression {
-            setEmitFlags(node, EmitFlags.NoSubstitution);
-
-            const left = node.left;
-            switch (left.kind) {
-                case SyntaxKind.Identifier:
-                    const exportDeclaration = resolver.getReferencedExportContainer(<Identifier>left);
-                    if (exportDeclaration) {
-                        return createExportExpression(<Identifier>left, node);
-                    }
-                    break;
-
-                case SyntaxKind.ObjectLiteralExpression:
-                case SyntaxKind.ArrayLiteralExpression:
-                    if (hasExportedReferenceInDestructuringPattern(<ObjectLiteralExpression | ArrayLiteralExpression>left)) {
-                        return substituteDestructuring(node);
+            if (isBindingPattern(decl.name)) {
+                for (const element of decl.name.elements) {
+                    if (!isOmittedExpression(element)) {
+                        statements = appendExportsOfBindingElement(statements, element, exportSelf);
                     }
-                    break;
+                }
             }
+            else if (!isGeneratedIdentifier(decl.name)) {
+                let excludeName: string;
+                if (exportSelf) {
+                    statements = appendExportStatement(statements, decl.name, getLocalName(decl));
+                    excludeName = decl.name.text;
+                }
 
-            return node;
-        }
-
-        function isExportedBinding(name: Identifier) {
-            const container = resolver.getReferencedExportContainer(name);
-            return container && container.kind === SyntaxKind.SourceFile;
-        }
-
-        function hasExportedReferenceInDestructuringPattern(node: ObjectLiteralExpression | ArrayLiteralExpression | Identifier): boolean {
-            switch (node.kind) {
-                case SyntaxKind.Identifier:
-                    return isExportedBinding(<Identifier>node);
-
-                case SyntaxKind.ObjectLiteralExpression:
-                    for (const property of (<ObjectLiteralExpression>node).properties) {
-                        if (hasExportedReferenceInObjectDestructuringElement(property)) {
-                            return true;
-                        }
-                    }
-
-                    break;
-
-                case SyntaxKind.ArrayLiteralExpression:
-                    for (const element of (<ArrayLiteralExpression>node).elements) {
-                        if (hasExportedReferenceInArrayDestructuringElement(element)) {
-                            return true;
-                        }
-                    }
-
-                    break;
+                statements = appendExportsOfDeclaration(statements, decl, excludeName);
             }
 
-            return false;
+            return statements;
         }
 
-        function hasExportedReferenceInObjectDestructuringElement(node: ObjectLiteralElementLike): boolean {
-            if (isShorthandPropertyAssignment(node)) {
-                return isExportedBinding(node.name);
-            }
-            else if (isPropertyAssignment(node)) {
-                return hasExportedReferenceInDestructuringElement(node.initializer);
-            }
-            else {
-                return false;
+        /**
+         * Appends the exports of a ClassDeclaration or FunctionDeclaration to a statement list,
+         * returning the statement list.
+         *
+         * @param statements A statement list to which the down-level export statements are to be
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
+         * @param decl The declaration whose exports are to be recorded.
+         */
+        function appendExportsOfHoistedDeclaration(statements: Statement[] | undefined, decl: ClassDeclaration | FunctionDeclaration): Statement[] | undefined {
+            if (moduleInfo.exportEquals) {
+                return statements;
             }
-        }
 
-        function hasExportedReferenceInArrayDestructuringElement(node: Expression): boolean {
-            if (isSpreadElementExpression(node)) {
-                const expression = node.expression;
-                return isIdentifier(expression) && isExportedBinding(expression);
-            }
-            else {
-                return hasExportedReferenceInDestructuringElement(node);
+            let excludeName: string;
+            if (hasModifier(decl, ModifierFlags.Export)) {
+                const exportName = hasModifier(decl, ModifierFlags.Default) ? createLiteral("default") : decl.name;
+                statements = appendExportStatement(statements, exportName, getLocalName(decl));
+                excludeName = exportName.text;
             }
-        }
 
-        function hasExportedReferenceInDestructuringElement(node: Expression): boolean {
-            if (isBinaryExpression(node)) {
-                const left = node.left;
-                return node.operatorToken.kind === SyntaxKind.EqualsToken
-                    && isDestructuringPattern(left)
-                    && hasExportedReferenceInDestructuringPattern(left);
-            }
-            else if (isIdentifier(node)) {
-                return isExportedBinding(node);
-            }
-            else if (isSpreadElementExpression(node)) {
-                const expression = node.expression;
-                return isIdentifier(expression) && isExportedBinding(expression);
-            }
-            else if (isDestructuringPattern(node)) {
-                return hasExportedReferenceInDestructuringPattern(node);
-            }
-            else {
-                return false;
+            if (decl.name) {
+                statements = appendExportsOfDeclaration(statements, decl, excludeName);
             }
-        }
-
-        function isDestructuringPattern(node: Expression): node is ObjectLiteralExpression | ArrayLiteralExpression | Identifier {
-            const kind = node.kind;
-            return kind === SyntaxKind.Identifier
-                || kind === SyntaxKind.ObjectLiteralExpression
-                || kind === SyntaxKind.ArrayLiteralExpression;
-        }
 
-        function substituteDestructuring(node: BinaryExpression) {
-            return flattenDestructuringAssignment(context, node, /*needsValue*/ true, hoistVariableDeclaration);
+            return statements;
         }
 
-        function substituteUnaryExpression(node: PrefixUnaryExpression | PostfixUnaryExpression): Expression {
-            const operand = node.operand;
-            const operator = node.operator;
-            const substitute =
-                isIdentifier(operand) &&
-                (
-                    node.kind === SyntaxKind.PostfixUnaryExpression ||
-                    (node.kind === SyntaxKind.PrefixUnaryExpression && (operator === SyntaxKind.PlusPlusToken || operator === SyntaxKind.MinusMinusToken))
-                );
+        /**
+         * Appends the exports of a declaration to a statement list, returning the statement list.
+         *
+         * @param statements A statement list to which the down-level export statements are to be
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
+         * @param decl The declaration to export.
+         * @param excludeName An optional name to exclude from exports.
+         */
+        function appendExportsOfDeclaration(statements: Statement[] | undefined, decl: Declaration, excludeName?: string): Statement[] | undefined {
+            if (moduleInfo.exportEquals) {
+                return statements;
+            }
 
-            if (substitute) {
-                const exportDeclaration = resolver.getReferencedExportContainer(<Identifier>operand);
-                if (exportDeclaration) {
-                    const expr = createPrefix(node.operator, operand, node);
-                    setEmitFlags(expr, EmitFlags.NoSubstitution);
-                    const call = createExportExpression(<Identifier>operand, expr);
-                    if (node.kind === SyntaxKind.PrefixUnaryExpression) {
-                        return call;
-                    }
-                    else {
-                        // export function returns the value that was passes as the second argument
-                        // however for postfix unary expressions result value should be the value before modification.
-                        // emit 'x++' as '(export('x', ++x) - 1)' and 'x--' as '(export('x', --x) + 1)'
-                        return operator === SyntaxKind.PlusPlusToken
-                            ? createSubtract(call, createLiteral(1))
-                            : createAdd(call, createLiteral(1));
+            const name = getDeclarationName(decl);
+            const exportSpecifiers = moduleInfo.exportSpecifiers[name.text];
+            if (exportSpecifiers) {
+                for (const exportSpecifier of exportSpecifiers) {
+                    if (exportSpecifier.name.text !== excludeName) {
+                        statements = appendExportStatement(statements, exportSpecifier.name, name);
                     }
                 }
             }
-            return node;
+            return statements;
         }
 
         /**
-         * Gets a name to use for a DeclarationStatement.
-         * @param node The declaration statement.
+         * Appends the down-level representation of an export to a statement list, returning the
+         * statement list.
+         *
+         * @param statements A statement list to which the down-level export statements are to be
+         * appended. If `statements` is `undefined`, a new array is allocated if statements are
+         * appended.
+         * @param exportName The name of the export.
+         * @param expression The expression to export.
+         * @param allowComments Whether to allow comments on the export.
          */
-        function getDeclarationName(node: DeclarationStatement) {
-            return node.name ? getSynthesizedClone(<Identifier>node.name) : getGeneratedNameForNode(node);
-        }
-
-        function addExportStarFunction(statements: Statement[], localNames: Identifier) {
-            const exportStarFunction = createUniqueName("exportStar");
-            const m = createIdentifier("m");
-            const n = createIdentifier("n");
-            const exports = createIdentifier("exports");
-            let condition: Expression = createStrictInequality(n, createLiteral("default"));
-            if (localNames) {
-                condition = createLogicalAnd(
-                    condition,
-                    createLogicalNot(createHasOwnProperty(localNames, n))
-                );
-            }
-
-            statements.push(
-                createFunctionDeclaration(
-                    /*decorators*/ undefined,
-                    /*modifiers*/ undefined,
-                    /*asteriskToken*/ undefined,
-                    exportStarFunction,
-                    /*typeParameters*/ undefined,
-                    [createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, m)],
-                    /*type*/ undefined,
-                    createBlock([
-                        createVariableStatement(
-                            /*modifiers*/ undefined,
-                            createVariableDeclarationList([
-                                createVariableDeclaration(
-                                    exports,
-                                    /*type*/ undefined,
-                                    createObjectLiteral([])
-                                )
-                            ])
-                        ),
-                        createForIn(
-                            createVariableDeclarationList([
-                                createVariableDeclaration(n, /*type*/ undefined)
-                            ]),
-                            m,
-                            createBlock([
-                                setEmitFlags(
-                                    createIf(
-                                        condition,
-                                        createStatement(
-                                            createAssignment(
-                                                createElementAccess(exports, n),
-                                                createElementAccess(m, n)
-                                            )
-                                        )
-                                    ),
-                                    EmitFlags.SingleLine
-                                )
-                            ])
-                        ),
-                        createStatement(
-                            createCall(
-                                exportFunctionForFile,
-                                /*typeArguments*/ undefined,
-                                [exports]
-                            )
-                        )
-                    ],
-                    /*location*/ undefined,
-                    /*multiline*/ true)
-                )
-            );
-
-            return exportStarFunction;
+        function appendExportStatement(statements: Statement[] | undefined, exportName: Identifier | StringLiteral, expression: Expression, allowComments?: boolean): Statement[] | undefined {
+            statements = append(statements, createExportStatement(exportName, expression, allowComments));
+            return statements;
         }
 
         /**
          * Creates a call to the current file's export function to export a value.
+         *
          * @param name The bound name of the export.
          * @param value The exported value.
+         * @param allowComments An optional value indicating whether to emit comments for the statement.
          */
-        function createExportExpression(name: Identifier | StringLiteral, value: Expression) {
-            const exportName = isIdentifier(name) ? createLiteral(name.text) : name;
-            return createCall(exportFunctionForFile, /*typeArguments*/ undefined, [exportName, value]);
+        function createExportStatement(name: Identifier | StringLiteral, value: Expression, allowComments?: boolean) {
+            const statement = createStatement(createExportExpression(name, value));
+            startOnNewLine(statement);
+            if (!allowComments) {
+                setEmitFlags(statement, EmitFlags.NoComments);
+            }
+
+            return statement;
         }
 
         /**
          * Creates a call to the current file's export function to export a value.
+         *
          * @param name The bound name of the export.
          * @param value The exported value.
          */
-        function createExportStatement(name: Identifier | StringLiteral, value: Expression) {
-            return createStatement(createExportExpression(name, value));
+        function createExportExpression(name: Identifier | StringLiteral, value: Expression) {
+            const exportName = isIdentifier(name) ? createLiteral(name) : name;
+            return createCall(exportFunction, /*typeArguments*/ undefined, [exportName, value]);
         }
 
+        //
+        // Top-Level or Nested Source Element Visitors
+        //
+
         /**
-         * Creates a call to the current file's export function to export a declaration.
-         * @param node The declaration to export.
+         * Visit nested elements at the top-level of a module.
+         *
+         * @param node The node to visit.
          */
-        function createDeclarationExport(node: DeclarationStatement) {
-            const declarationName = getDeclarationName(node);
-            const exportName = hasModifier(node, ModifierFlags.Default) ? createLiteral("default") : declarationName;
-            return createExportStatement(exportName, declarationName);
-        }
+        function nestedElementVisitor(node: Node): VisitResult<Node> {
+            switch (node.kind) {
+                case SyntaxKind.VariableStatement:
+                    return visitVariableStatement(<VariableStatement>node);
 
-        function createImportBinding(importDeclaration: Declaration): LeftHandSideExpression {
-            let importAlias: Identifier;
-            let name: Identifier;
-            if (isImportClause(importDeclaration)) {
-                importAlias = getGeneratedNameForNode(importDeclaration.parent);
-                name = createIdentifier("default");
-            }
-            else if (isImportSpecifier(importDeclaration)) {
-                importAlias = getGeneratedNameForNode(importDeclaration.parent.parent.parent);
-                name = importDeclaration.propertyName || importDeclaration.name;
-            }
-            else {
-                return undefined;
-            }
+                case SyntaxKind.FunctionDeclaration:
+                    return visitFunctionDeclaration(<FunctionDeclaration>node);
 
-            return createPropertyAccess(importAlias, getSynthesizedClone(name));
-        }
+                case SyntaxKind.ClassDeclaration:
+                    return visitClassDeclaration(<ClassDeclaration>node);
 
-        function collectDependencyGroups(externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[]) {
-            const groupIndices = createMap<number>();
-            const dependencyGroups: DependencyGroup[] = [];
-            for (let i = 0; i < externalImports.length; i++) {
-                const externalImport = externalImports[i];
-                const externalModuleName = getExternalModuleNameLiteral(externalImport, currentSourceFile, host, resolver, compilerOptions);
-                const text = externalModuleName.text;
-                if (hasProperty(groupIndices, text)) {
-                    // deduplicate/group entries in dependency list by the dependency name
-                    const groupIndex = groupIndices[text];
-                    dependencyGroups[groupIndex].externalImports.push(externalImport);
-                    continue;
-                }
-                else {
-                    groupIndices[text] = dependencyGroups.length;
-                    dependencyGroups.push({
-                        name: externalModuleName,
-                        externalImports: [externalImport]
-                    });
+                case SyntaxKind.ForStatement:
+                    return visitForStatement(<ForStatement>node);
+
+                case SyntaxKind.ForInStatement:
+                    return visitForInStatement(<ForInStatement>node);
+
+                case SyntaxKind.ForOfStatement:
+                    return visitForOfStatement(<ForOfStatement>node);
+
+                case SyntaxKind.DoStatement:
+                    return visitDoStatement(<DoStatement>node);
+
+                case SyntaxKind.WhileStatement:
+                    return visitWhileStatement(<WhileStatement>node);
+
+                case SyntaxKind.LabeledStatement:
+                    return visitLabeledStatement(<LabeledStatement>node);
+
+                case SyntaxKind.WithStatement:
+                    return visitWithStatement(<WithStatement>node);
+
+                case SyntaxKind.SwitchStatement:
+                    return visitSwitchStatement(<SwitchStatement>node);
+
+                case SyntaxKind.CaseBlock:
+                    return visitCaseBlock(<CaseBlock>node);
+
+                case SyntaxKind.CaseClause:
+                    return visitCaseClause(<CaseClause>node);
+
+                case SyntaxKind.DefaultClause:
+                    return visitDefaultClause(<DefaultClause>node);
+
+                case SyntaxKind.TryStatement:
+                    return visitTryStatement(<TryStatement>node);
+
+                case SyntaxKind.CatchClause:
+                    return visitCatchClause(<CatchClause>node);
+
+                case SyntaxKind.Block:
+                    return visitBlock(<Block>node);
+
+                case SyntaxKind.MergeDeclarationMarker:
+                    return visitMergeDeclarationMarker(<MergeDeclarationMarker>node);
+
+                case SyntaxKind.EndOfDeclarationMarker:
+                    return visitEndOfDeclarationMarker(<EndOfDeclarationMarker>node);
+
+                default:
+                    return destructuringVisitor(node);
+            }
+        }
+
+        /**
+         * Visits the body of a ForStatement to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitForStatement(node: ForStatement): VisitResult<Statement> {
+            const savedEnclosingBlockScopedContainer = enclosingBlockScopedContainer;
+            enclosingBlockScopedContainer = node;
+
+            node = updateFor(
+                node,
+                visitForInitializer(node.initializer),
+                visitNode(node.condition, destructuringVisitor, isExpression, /*optional*/ true),
+                visitNode(node.incrementor, destructuringVisitor, isExpression, /*optional*/ true),
+                visitNode(node.statement, nestedElementVisitor, isStatement)
+            );
+
+            enclosingBlockScopedContainer = savedEnclosingBlockScopedContainer;
+            return node;
+        }
+
+        /**
+         * Visits the body of a ForInStatement to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitForInStatement(node: ForInStatement): VisitResult<Statement> {
+            const savedEnclosingBlockScopedContainer = enclosingBlockScopedContainer;
+            enclosingBlockScopedContainer = node;
+
+            node = updateForIn(
+                node,
+                visitForInitializer(node.initializer),
+                visitNode(node.expression, destructuringVisitor, isExpression),
+                visitNode(node.statement, nestedElementVisitor, isStatement, /*optional*/ false, liftToBlock)
+            );
+
+            enclosingBlockScopedContainer = savedEnclosingBlockScopedContainer;
+            return node;
+        }
+
+        /**
+         * Visits the body of a ForOfStatement to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitForOfStatement(node: ForOfStatement): VisitResult<Statement> {
+            const savedEnclosingBlockScopedContainer = enclosingBlockScopedContainer;
+            enclosingBlockScopedContainer = node;
+
+            node = updateForOf(
+                node,
+                visitForInitializer(node.initializer),
+                visitNode(node.expression, destructuringVisitor, isExpression),
+                visitNode(node.statement, nestedElementVisitor, isStatement, /*optional*/ false, liftToBlock)
+            );
+
+            enclosingBlockScopedContainer = savedEnclosingBlockScopedContainer;
+            return node;
+        }
+
+        /**
+         * Determines whether to hoist the initializer of a ForStatement, ForInStatement, or
+         * ForOfStatement.
+         *
+         * @param node The node to test.
+         */
+        function shouldHoistForInitializer(node: ForInitializer): node is VariableDeclarationList {
+            return isVariableDeclarationList(node)
+                && shouldHoistVariableDeclarationList(node);
+        }
+
+        /**
+         * Visits the initializer of a ForStatement, ForInStatement, or ForOfStatement
+         *
+         * @param node The node to visit.
+         */
+        function visitForInitializer(node: ForInitializer): ForInitializer {
+            if (shouldHoistForInitializer(node)) {
+                let expressions: Expression[];
+                for (const variable of node.declarations) {
+                    expressions = append(expressions, transformInitializedVariable(variable, /*isExportedDeclaration*/ false));
                 }
+
+                return expressions ? inlineExpressions(expressions) : createOmittedExpression();
+            }
+            else {
+                return visitEachChild(node, nestedElementVisitor, context);
             }
+        }
 
-            return dependencyGroups;
+        /**
+         * Visits the body of a DoStatement to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitDoStatement(node: DoStatement): VisitResult<Statement> {
+            return updateDo(
+                node,
+                visitNode(node.statement, nestedElementVisitor, isStatement, /*optional*/ false, liftToBlock),
+                visitNode(node.expression, destructuringVisitor, isExpression)
+            );
+        }
+
+        /**
+         * Visits the body of a WhileStatement to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitWhileStatement(node: WhileStatement): VisitResult<Statement> {
+            return updateWhile(
+                node,
+                visitNode(node.expression, destructuringVisitor, isExpression),
+                visitNode(node.statement, nestedElementVisitor, isStatement, /*optional*/ false, liftToBlock)
+            );
         }
 
-        function getNameOfDependencyGroup(dependencyGroup: DependencyGroup) {
-            return dependencyGroup.name;
+        /**
+         * Visits the body of a LabeledStatement to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitLabeledStatement(node: LabeledStatement): VisitResult<Statement> {
+            return updateLabel(
+                node,
+                node.label,
+                visitNode(node.statement, nestedElementVisitor, isStatement, /*optional*/ false, liftToBlock)
+            );
         }
 
-        function recordExportName(name: Identifier) {
-            if (!exportedLocalNames) {
-                exportedLocalNames = [];
+        /**
+         * Visits the body of a WithStatement to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitWithStatement(node: WithStatement): VisitResult<Statement> {
+            return updateWith(
+                node,
+                visitNode(node.expression, destructuringVisitor, isExpression),
+                visitNode(node.statement, nestedElementVisitor, isStatement, /*optional*/ false, liftToBlock)
+            );
+        }
+
+        /**
+         * Visits the body of a SwitchStatement to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitSwitchStatement(node: SwitchStatement): VisitResult<Statement> {
+            return updateSwitch(
+                node,
+                visitNode(node.expression, destructuringVisitor, isExpression),
+                visitNode(node.caseBlock, nestedElementVisitor, isCaseBlock)
+            );
+        }
+
+        /**
+         * Visits the body of a CaseBlock to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitCaseBlock(node: CaseBlock): CaseBlock {
+            const savedEnclosingBlockScopedContainer = enclosingBlockScopedContainer;
+            enclosingBlockScopedContainer = node;
+
+            node = updateCaseBlock(
+                node,
+                visitNodes(node.clauses, nestedElementVisitor, isCaseOrDefaultClause)
+            );
+
+            enclosingBlockScopedContainer = savedEnclosingBlockScopedContainer;
+            return node;
+        }
+
+        /**
+         * Visits the body of a CaseClause to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitCaseClause(node: CaseClause): VisitResult<CaseOrDefaultClause> {
+            return updateCaseClause(
+                node,
+                visitNode(node.expression, destructuringVisitor, isExpression),
+                visitNodes(node.statements, nestedElementVisitor, isStatement)
+            );
+        }
+
+        /**
+         * Visits the body of a DefaultClause to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitDefaultClause(node: DefaultClause): VisitResult<CaseOrDefaultClause> {
+            return visitEachChild(node, nestedElementVisitor, context);
+        }
+
+        /**
+         * Visits the body of a TryStatement to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitTryStatement(node: TryStatement): VisitResult<Statement> {
+            return visitEachChild(node, nestedElementVisitor, context);
+        }
+
+        /**
+         * Visits the body of a CatchClause to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitCatchClause(node: CatchClause): CatchClause {
+            const savedEnclosingBlockScopedContainer = enclosingBlockScopedContainer;
+            enclosingBlockScopedContainer = node;
+
+            node = updateCatchClause(
+                node,
+                node.variableDeclaration,
+                visitNode(node.block, nestedElementVisitor, isBlock)
+            );
+
+            enclosingBlockScopedContainer = savedEnclosingBlockScopedContainer;
+            return node;
+        }
+
+        /**
+         * Visits the body of a Block to hoist declarations.
+         *
+         * @param node The node to visit.
+         */
+        function visitBlock(node: Block): Block {
+            const savedEnclosingBlockScopedContainer = enclosingBlockScopedContainer;
+            enclosingBlockScopedContainer = node;
+
+            node = visitEachChild(node, nestedElementVisitor, context);
+
+            enclosingBlockScopedContainer = savedEnclosingBlockScopedContainer;
+            return node;
+        }
+
+        //
+        // Destructuring Assignment Visitors
+        //
+
+        /**
+         * Visit nodes to flatten destructuring assignments to exported symbols.
+         *
+         * @param node The node to visit.
+         */
+        function destructuringVisitor(node: Node): VisitResult<Node> {
+            if (node.transformFlags & TransformFlags.DestructuringAssignment
+                && node.kind === SyntaxKind.BinaryExpression) {
+                return visitDestructuringAssignment(<DestructuringAssignment>node);
+            }
+            else if (node.transformFlags & TransformFlags.ContainsDestructuringAssignment) {
+                return visitEachChild(node, destructuringVisitor, context);
+            }
+            else {
+                return node;
             }
+        }
 
-            exportedLocalNames.push(name);
+        /**
+         * Visits a DestructuringAssignment to flatten destructuring to exported symbols.
+         *
+         * @param node The node to visit.
+         */
+        function visitDestructuringAssignment(node: DestructuringAssignment): VisitResult<Expression> {
+            if (hasExportedReferenceInDestructuringTarget(node.left)) {
+                return flattenDestructuringAssignment(context, node, /*needsValue*/ true, hoistVariableDeclaration, destructuringVisitor);
+            }
+
+            return visitEachChild(node, destructuringVisitor, context);
         }
 
-        function recordExportedFunctionDeclaration(node: FunctionDeclaration) {
-            if (!exportedFunctionDeclarations) {
-                exportedFunctionDeclarations = [];
+        /**
+         * Determines whether the target of a destructuring assigment refers to an exported symbol.
+         *
+         * @param node The destructuring target.
+         */
+        function hasExportedReferenceInDestructuringTarget(node: Expression | ObjectLiteralElementLike): boolean {
+            if (isAssignmentExpression(node)) {
+                return hasExportedReferenceInDestructuringTarget(node.left);
+            }
+            else if (isSpreadElementExpression(node)) {
+                return hasExportedReferenceInDestructuringTarget(node.expression);
+            }
+            else if (isObjectLiteralExpression(node)) {
+                return some(node.properties, hasExportedReferenceInDestructuringTarget);
+            }
+            else if (isArrayLiteralExpression(node)) {
+                return some(node.elements, hasExportedReferenceInDestructuringTarget);
+            }
+            else if (isShorthandPropertyAssignment(node)) {
+                return hasExportedReferenceInDestructuringTarget(node.name);
+            }
+            else if (isPropertyAssignment(node)) {
+                return hasExportedReferenceInDestructuringTarget(node.initializer);
             }
+            else if (isIdentifier(node)) {
+                const container = resolver.getReferencedExportContainer(node);
+                return container !== undefined && container.kind === SyntaxKind.SourceFile;
+            }
+            else {
+                return false;
+            }
+        }
 
-            exportedFunctionDeclarations.push(createDeclarationExport(node));
+        //
+        // Modifier Visitors
+        //
+
+        /**
+         * Visit nodes to elide module-specific modifiers.
+         *
+         * @param node The node to visit.
+         */
+        function modifierVisitor(node: Node): VisitResult<Node> {
+            switch (node.kind) {
+                case SyntaxKind.ExportKeyword:
+                case SyntaxKind.DefaultKeyword:
+                    return undefined;
+            }
+            return node;
         }
 
-        function hoistBindingElement(node: VariableDeclaration | ArrayBindingElement, isExported: boolean): void {
-            if (isOmittedExpression(node)) {
-                return;
+        //
+        // Emit Notification
+        //
+
+        /**
+         * Hook for node emit notifications.
+         *
+         * @param emitContext A context hint for the emitter.
+         * @param node The node to emit.
+         * @param emit A callback used to emit the node in the printer.
+         */
+        function onEmitNode(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void {
+            if (node.kind === SyntaxKind.SourceFile) {
+                const id = getOriginalNodeId(node);
+                currentSourceFile = <SourceFile>node;
+                moduleInfo = moduleInfoMap[id];
+                exportFunction = exportFunctionsMap[id];
+                noSubstitution = noSubstitutionMap[id];
+
+                if (noSubstitution) {
+                    delete noSubstitutionMap[id];
+                }
+
+                previousOnEmitNode(emitContext, node, emitCallback);
+
+                currentSourceFile = undefined;
+                moduleInfo = undefined;
+                exportFunction = undefined;
+                noSubstitution = undefined;
+            }
+            else {
+                previousOnEmitNode(emitContext, node, emitCallback);
+            }
+        }
+
+        //
+        // Substitutions
+        //
+
+        /**
+         * Hooks node substitutions.
+         *
+         * @param emitContext A context hint for the emitter.
+         * @param node The node to substitute.
+         */
+        function onSubstituteNode(emitContext: EmitContext, node: Node) {
+            node = previousOnSubstituteNode(emitContext, node);
+            if (isSubstitutionPrevented(node)) {
+                return node;
+            }
+
+            if (emitContext === EmitContext.Expression) {
+                return substituteExpression(<Expression>node);
+            }
+
+            return node;
+        }
+
+        /**
+         * Substitute the expression, if necessary.
+         *
+         * @param node The node to substitute.
+         */
+        function substituteExpression(node: Expression) {
+            switch (node.kind) {
+                case SyntaxKind.Identifier:
+                    return substituteExpressionIdentifier(<Identifier>node);
+                case SyntaxKind.BinaryExpression:
+                    return substituteBinaryExpression(<BinaryExpression>node);
+                case SyntaxKind.PrefixUnaryExpression:
+                case SyntaxKind.PostfixUnaryExpression:
+                    return substituteUnaryExpression(<PrefixUnaryExpression | PostfixUnaryExpression>node);
             }
 
-            const name = node.name;
-            if (isIdentifier(name)) {
-                hoistVariableDeclaration(getSynthesizedClone(name));
-                if (isExported) {
-                    recordExportName(name);
+            return node;
+        }
+
+        /**
+         * Substitution for an Identifier expression that may contain an imported or exported symbol.
+         *
+         * @param node The node to substitute.
+         */
+        function substituteExpressionIdentifier(node: Identifier): Expression {
+            // When we see an identifier in an expression position that
+            // points to an imported symbol, we should substitute a qualified
+            // reference to the imported symbol if one is needed.
+            //
+            // - We do not substitute generated identifiers for any reason.
+            // - We do not substitute identifiers tagged with the LocalName flag.
+            if (!isGeneratedIdentifier(node) && !isLocalName(node)) {
+                const importDeclaration = resolver.getReferencedImportDeclaration(node);
+                if (importDeclaration) {
+                    if (isImportClause(importDeclaration)) {
+                        return createPropertyAccess(
+                            getGeneratedNameForNode(importDeclaration.parent),
+                            createIdentifier("default"),
+                            /*location*/ node
+                        );
+                    }
+                    else if (isImportSpecifier(importDeclaration)) {
+                        return createPropertyAccess(
+                            getGeneratedNameForNode(importDeclaration.parent.parent.parent),
+                            getSynthesizedClone(importDeclaration.propertyName || importDeclaration.name),
+                            /*location*/ node
+                        );
+                    }
                 }
             }
-            else if (isBindingPattern(name)) {
-                forEach(name.elements, isExported ? hoistExportedBindingElement : hoistNonExportedBindingElement);
+
+            return node;
+        }
+
+        /**
+         * Substitution for a BinaryExpression that may contain an imported or exported symbol.
+         *
+         * @param node The node to substitute.
+         */
+        function substituteBinaryExpression(node: BinaryExpression): Expression {
+            // When we see an assignment expression whose left-hand side is an exported symbol,
+            // we should ensure all exports of that symbol are updated with the correct value.
+            //
+            // - We do not substitute generated identifiers for any reason.
+            // - We do not substitute identifiers tagged with the LocalName flag.
+            // - We do not substitute identifiers that were originally the name of an enum or
+            //   namespace due to how they are transformed in TypeScript.
+            // - We only substitute identifiers that are exported at the top level.
+            if (isAssignmentOperator(node.operatorToken.kind)
+                && isIdentifier(node.left)
+                && !isGeneratedIdentifier(node.left)
+                && !isLocalName(node.left)
+                && !isDeclarationNameOfEnumOrNamespace(node.left)) {
+                const exportedNames = getExports(node.left);
+                if (exportedNames) {
+                    // For each additional export of the declaration, apply an export assignment.
+                    let expression: Expression = node;
+                    for (const exportName of exportedNames) {
+                        expression = createExportExpression(exportName, preventSubstitution(expression));
+                    }
+
+                    return expression;
+                }
             }
+
+            return node;
         }
 
-        function hoistExportedBindingElement(node: VariableDeclaration | ArrayBindingElement) {
-            hoistBindingElement(node, /*isExported*/ true);
+        /**
+         * Substitution for a UnaryExpression that may contain an imported or exported symbol.
+         *
+         * @param node The node to substitute.
+         */
+        function substituteUnaryExpression(node: PrefixUnaryExpression | PostfixUnaryExpression): Expression {
+            // When we see a prefix or postfix increment expression whose operand is an exported
+            // symbol, we should ensure all exports of that symbol are updated with the correct
+            // value.
+            //
+            // - We do not substitute generated identifiers for any reason.
+            // - We do not substitute identifiers tagged with the LocalName flag.
+            // - We do not substitute identifiers that were originally the name of an enum or
+            //   namespace due to how they are transformed in TypeScript.
+            // - We only substitute identifiers that are exported at the top level.
+            if ((node.operator === SyntaxKind.PlusPlusToken || node.operator === SyntaxKind.MinusMinusToken)
+                && isIdentifier(node.operand)
+                && !isGeneratedIdentifier(node.operand)
+                && !isLocalName(node.operand)
+                && !isDeclarationNameOfEnumOrNamespace(node.operand)) {
+                const exportedNames = getExports(node.operand);
+                if (exportedNames) {
+                    let expression: Expression = node.kind === SyntaxKind.PostfixUnaryExpression
+                        ? createPrefix(
+                            node.operator,
+                            node.operand,
+                            /*location*/ node)
+                        : node;
+
+                    for (const exportName of exportedNames) {
+                        expression = createExportExpression(exportName, preventSubstitution(expression));
+                    }
+
+                    if (node.kind === SyntaxKind.PostfixUnaryExpression) {
+                        expression = node.operator === SyntaxKind.PlusPlusToken
+                            ? createSubtract(preventSubstitution(expression), createLiteral(1))
+                            : createAdd(preventSubstitution(expression), createLiteral(1));
+                    }
+
+                    return expression;
+                }
+            }
+
+            return node;
         }
 
-        function hoistNonExportedBindingElement(node: VariableDeclaration | ArrayBindingElement) {
-            hoistBindingElement(node, /*isExported*/ false);
+        /**
+         * Gets the exports of a name.
+         *
+         * @param name The name.
+         */
+        function getExports(name: Identifier) {
+            let exportedNames: Identifier[];
+            if (!isGeneratedIdentifier(name)) {
+                const valueDeclaration = resolver.getReferencedImportDeclaration(name)
+                    || resolver.getReferencedValueDeclaration(name);
+
+                if (valueDeclaration) {
+                    const exportContainer = resolver.getReferencedExportContainer(name, /*prefixLocals*/ false);
+                    if (exportContainer && exportContainer.kind === SyntaxKind.SourceFile) {
+                        exportedNames = append(exportedNames, getDeclarationName(valueDeclaration));
+                    }
+
+                    exportedNames = addRange(exportedNames, moduleInfo && moduleInfo.exportedBindings[getOriginalNodeId(valueDeclaration)]);
+                }
+            }
+
+            return exportedNames;
         }
 
-        function updateSourceFile(node: SourceFile, statements: Statement[], nodeEmitFlags: EmitFlags) {
-            const updated = getMutableClone(node);
-            updated.statements = createNodeArray(statements, node.statements);
-            setEmitFlags(updated, nodeEmitFlags);
-            return updated;
+        /**
+         * Prevent substitution of a node for this transformer.
+         *
+         * @param node The node which should not be substituted.
+         */
+        function preventSubstitution<T extends Node>(node: T): T {
+            if (noSubstitution === undefined) noSubstitution = createMap<boolean>();
+            noSubstitution[getNodeId(node)] = true;
+            return node;
+        }
+
+        /**
+         * Determines whether a node should not be substituted.
+         *
+         * @param node The node to test.
+         */
+        function isSubstitutionPrevented(node: Node) {
+            return noSubstitution && node.id && noSubstitution[node.id];
         }
     }
 }
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 0e1821159bec0..6d2d70e7fbda1 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -2353,7 +2353,7 @@ namespace ts {
                     context,
                     node,
                     hoistVariableDeclaration,
-                    getNamespaceMemberNameWithSourceMapsAndWithoutComments,
+                    createNamespaceExportExpression,
                     visitor
                 );
             }
@@ -2709,9 +2709,13 @@ namespace ts {
                 return true;
             }
             else {
-                const notEmittedStatement = createNotEmittedStatement(statement);
-                setEmitFlags(notEmittedStatement, EmitFlags.NoComments);
-                statements.push(notEmittedStatement);
+                // For an EnumDeclaration or ModuleDeclaration that merges with a preceeding
+                // declaration we do not emit a leading variable declaration. To preserve the
+                // begin/end semantics of the declararation and to properly handle exports
+                // we wrap the leading variable declaration in a `MergeDeclarationMarker`.
+                const mergeMarker = createMergeDeclarationMarker(statement);
+                setEmitFlags(mergeMarker, EmitFlags.NoComments | EmitFlags.HasEndOfDeclarationMarker);
+                statements.push(mergeMarker);
                 return false;
             }
         }
@@ -3061,10 +3065,13 @@ namespace ts {
                     createVariableStatement(
                         visitNodes(node.modifiers, modifierVisitor, isModifier),
                         createVariableDeclarationList([
-                            createVariableDeclaration(
-                                node.name,
-                                /*type*/ undefined,
-                                moduleReference
+                            setOriginalNode(
+                                createVariableDeclaration(
+                                    node.name,
+                                    /*type*/ undefined,
+                                    moduleReference
+                                ),
+                                node
                             )
                         ]),
                         node
@@ -3152,6 +3159,10 @@ namespace ts {
             );
         }
 
+        function createNamespaceExportExpression(exportName: Identifier, exportValue: Expression, location?: TextRange) {
+            return createAssignment(getNamespaceMemberNameWithSourceMapsAndWithoutComments(exportName), exportValue, location);
+        }
+
         function getNamespaceMemberNameWithSourceMapsAndWithoutComments(name: Identifier) {
             return getNamespaceMemberName(currentNamespaceContainerName, name, /*allowComments*/ false, /*allowSourceMaps*/ true);
         }
@@ -3343,11 +3354,11 @@ namespace ts {
 
         function trySubstituteNamespaceExportedName(node: Identifier): Expression {
             // If this is explicitly a local name, do not substitute.
-            if (enabledSubstitutions & applicableSubstitutions && (getEmitFlags(node) & EmitFlags.LocalName) === 0) {
+            if (enabledSubstitutions & applicableSubstitutions && !isLocalName(node)) {
                 // If we are nested within a namespace declaration, we may need to qualifiy
                 // an identifier that is exported from a merged namespace.
                 const container = resolver.getReferencedExportContainer(node, /*prefixLocals*/ false);
-                if (container) {
+                if (container && container.kind !== SyntaxKind.SourceFile) {
                     const substitute =
                         (applicableSubstitutions & TypeScriptSubstitutionFlags.NamespaceExports && container.kind === SyntaxKind.ModuleDeclaration) ||
                         (applicableSubstitutions & TypeScriptSubstitutionFlags.NonQualifiedEnumMembers && container.kind === SyntaxKind.EnumDeclaration);
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 93fd9afb79c0e..2c3765210e758 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -362,6 +362,7 @@ namespace ts {
         // Transformation nodes
         NotEmittedStatement,
         PartiallyEmittedExpression,
+        MergeDeclarationMarker,
         EndOfDeclarationMarker,
 
         // Enum value count
@@ -1156,6 +1157,21 @@ namespace ts {
         right: Expression;
     }
 
+    export interface AssignmentExpression extends BinaryExpression {
+        left: LeftHandSideExpression;
+        operatorToken: Token<SyntaxKind.EqualsToken>;
+    }
+
+    export interface ObjectDestructuringAssignment extends AssignmentExpression {
+        left: ObjectLiteralExpression;
+    }
+
+    export interface ArrayDestructuringAssignment extends AssignmentExpression {
+        left: ArrayLiteralExpression;
+    }
+
+    export type DestructuringAssignment = ObjectDestructuringAssignment | ArrayDestructuringAssignment;
+
     export interface ConditionalExpression extends Expression {
         kind: SyntaxKind.ConditionalExpression;
         condition: Expression;
@@ -1436,6 +1452,14 @@ namespace ts {
         kind: SyntaxKind.EndOfDeclarationMarker;
     }
 
+    /**
+     * Marks the beginning of a merged transformed declaration.
+     */
+    /* @internal */
+    export interface MergeDeclarationMarker extends Statement {
+        kind: SyntaxKind.MergeDeclarationMarker;
+    }
+
     export interface EmptyStatement extends Statement {
         kind: SyntaxKind.EmptyStatement;
     }
@@ -3380,22 +3404,23 @@ namespace ts {
         Generator = 1 << 10,
         ContainsGenerator = 1 << 11,
         DestructuringAssignment = 1 << 12,
+        ContainsDestructuringAssignment = 1 << 13,
 
         // Markers
         // - Flags used to indicate that a subtree contains a specific transformation.
-        ContainsDecorators = 1 << 13,
-        ContainsPropertyInitializer = 1 << 14,
-        ContainsLexicalThis = 1 << 15,
-        ContainsCapturedLexicalThis = 1 << 16,
-        ContainsLexicalThisInComputedPropertyName = 1 << 17,
-        ContainsDefaultValueAssignments = 1 << 18,
-        ContainsParameterPropertyAssignments = 1 << 19,
-        ContainsSpreadElementExpression = 1 << 20,
-        ContainsComputedPropertyName = 1 << 21,
-        ContainsBlockScopedBinding = 1 << 22,
-        ContainsBindingPattern = 1 << 23,
-        ContainsYield = 1 << 24,
-        ContainsHoistedDeclarationOrCompletion = 1 << 25,
+        ContainsDecorators = 1 << 14,
+        ContainsPropertyInitializer = 1 << 15,
+        ContainsLexicalThis = 1 << 16,
+        ContainsCapturedLexicalThis = 1 << 17,
+        ContainsLexicalThisInComputedPropertyName = 1 << 18,
+        ContainsDefaultValueAssignments = 1 << 19,
+        ContainsParameterPropertyAssignments = 1 << 20,
+        ContainsSpreadElementExpression = 1 << 21,
+        ContainsComputedPropertyName = 1 << 22,
+        ContainsBlockScopedBinding = 1 << 23,
+        ContainsBindingPattern = 1 << 24,
+        ContainsYield = 1 << 25,
+        ContainsHoistedDeclarationOrCompletion = 1 << 26,
 
         HasComputedFlags = 1 << 29, // Transform flags have been computed.
 
@@ -3407,6 +3432,7 @@ namespace ts {
         AssertES2016 = ES2016 | ContainsES2016,
         AssertES2015 = ES2015 | ContainsES2015,
         AssertGenerator = Generator | ContainsGenerator,
+        AssertDestructuringAssignment = DestructuringAssignment | ContainsDestructuringAssignment,
 
         // Scope Exclusions
         // - Bitmasks that exclude flags from propagating out of a specific context
@@ -3464,7 +3490,6 @@ namespace ts {
         NoNestedComments = 1 << 16,
         ExportName = 1 << 17,                    // Ensure an export prefix is added for an identifier that points to an exported declaration with a local name (see SymbolFlags.ExportHasLocal).
         LocalName = 1 << 18,                     // Ensure an export prefix is not added for an identifier that points to an exported declaration.
-        ExportBindingName = LocalName | ExportName,
         Indented = 1 << 19,                      // Adds an explicit extra indentation level for class and function bodies when printing (used to match old emitter).
         NoIndentation = 1 << 20,                 // Do not indent the node.
         AsyncFunctionBody = 1 << 21,
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index ac0dd1af72062..91e95873a3f62 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -3084,7 +3084,13 @@ namespace ts {
         }
     }
 
-    export function isDestructuringAssignment(node: Node): node is BinaryExpression {
+    export function isAssignmentExpression(node: Node): node is AssignmentExpression {
+        return isBinaryExpression(node)
+            && isAssignmentOperator(node.operatorToken.kind)
+            && isLeftHandSideExpression(node.left);
+    }
+
+    export function isDestructuringAssignment(node: Node): node is DestructuringAssignment {
         if (isBinaryExpression(node)) {
             if (node.operatorToken.kind === SyntaxKind.EqualsToken) {
                 const kind = node.left.kind;
@@ -3522,6 +3528,7 @@ namespace ts {
         const exportSpecifiers = createMap<ExportSpecifier[]>();
         const exportedBindings = createMap<Identifier[]>();
         const uniqueExports = createMap<Identifier>();
+        let hasExportDefault = false;
         let exportEquals: ExportAssignment = undefined;
         let hasExportStarsToExportValues = false;
         for (const node of sourceFile.statements) {
@@ -3540,15 +3547,6 @@ namespace ts {
                         externalImports.push(<ImportEqualsDeclaration>node);
                     }
 
-                    if (hasModifier(node, ModifierFlags.Export)) {
-                        // export import x = ...
-                        const name = (<ImportEqualsDeclaration>node).name;
-                        if (!uniqueExports[name.text]) {
-                            multiMapAdd(exportedBindings, getOriginalNodeId(node), name);
-                            uniqueExports[name.text] = name;
-                        }
-                    }
-
                     break;
 
                 case SyntaxKind.ExportDeclaration:
@@ -3590,11 +3588,10 @@ namespace ts {
                     }
                     break;
 
-                case SyntaxKind.VariableDeclaration:
-                    // export var x
+                case SyntaxKind.VariableStatement:
                     if (hasModifier(node, ModifierFlags.Export)) {
                         for (const decl of (<VariableStatement>node).declarationList.declarations) {
-                            collectExportedVariableInfo(decl, exportedBindings, uniqueExports);
+                            collectExportedVariableInfo(decl, uniqueExports);
                         }
                     }
                     break;
@@ -3603,9 +3600,9 @@ namespace ts {
                     if (hasModifier(node, ModifierFlags.Export)) {
                         if (hasModifier(node, ModifierFlags.Default)) {
                             // export default function() { }
-                            if (!uniqueExports["default"]) {
+                            if (!hasExportDefault) {
                                 multiMapAdd(exportedBindings, getOriginalNodeId(node), getDeclarationName(<FunctionDeclaration>node));
-                                uniqueExports["default"] = createIdentifier("default");
+                                hasExportDefault = true;
                             }
                         }
                         else {
@@ -3623,8 +3620,9 @@ namespace ts {
                     if (hasModifier(node, ModifierFlags.Export)) {
                         if (hasModifier(node, ModifierFlags.Default)) {
                             // export default class { }
-                            if (!uniqueExports["default"]) {
+                            if (!hasExportDefault) {
                                 multiMapAdd(exportedBindings, getOriginalNodeId(node), getDeclarationName(<ClassDeclaration>node));
+                                hasExportDefault = true;
                             }
                         }
                         else {
@@ -3640,25 +3638,24 @@ namespace ts {
             }
         }
 
-        const exportedNames: Identifier[] = [];
+        let exportedNames: Identifier[];
         for (const key in uniqueExports) {
-            exportedNames.push(uniqueExports[key]);
+            exportedNames = ts.append(exportedNames, uniqueExports[key]);
         }
 
         return { externalImports, exportSpecifiers, exportEquals, hasExportStarsToExportValues, exportedBindings, exportedNames };
     }
 
-    function collectExportedVariableInfo(decl: VariableDeclaration | BindingElement, exportedNames: Map<Identifier[]>, uniqueExports: Map<Identifier>) {
+    function collectExportedVariableInfo(decl: VariableDeclaration | BindingElement, uniqueExports: Map<Identifier>) {
         if (isBindingPattern(decl.name)) {
             for (const element of decl.name.elements) {
                 if (!isOmittedExpression(element)) {
-                    collectExportedVariableInfo(element, exportedNames, uniqueExports);
+                    collectExportedVariableInfo(element, uniqueExports);
                 }
             }
         }
         else if (!isGeneratedIdentifier(decl.name)) {
             if (!uniqueExports[decl.name.text]) {
-                multiMapAdd(exportedNames, getOriginalNodeId(decl), decl.name);
                 uniqueExports[decl.name.text] = decl.name;
             }
         }
@@ -3901,6 +3898,14 @@ namespace ts {
 
     // Expression
 
+    export function isArrayLiteralExpression(node: Node): node is ArrayLiteralExpression {
+        return node.kind === SyntaxKind.ArrayLiteralExpression;
+    }
+
+    export function isObjectLiteralExpression(node: Node): node is ObjectLiteralExpression {
+        return node.kind === SyntaxKind.ObjectLiteralExpression;
+    }
+
     export function isPropertyAccessExpression(node: Node): node is PropertyAccessExpression {
         return node.kind === SyntaxKind.PropertyAccessExpression;
     }
@@ -4161,7 +4166,8 @@ namespace ts {
             || kind === SyntaxKind.WhileStatement
             || kind === SyntaxKind.WithStatement
             || kind === SyntaxKind.NotEmittedStatement
-            || kind === SyntaxKind.EndOfDeclarationMarker;
+            || kind === SyntaxKind.EndOfDeclarationMarker
+            || kind === SyntaxKind.MergeDeclarationMarker;
     }
 
     export function isDeclaration(node: Node): node is Declaration {
diff --git a/tests/baselines/reference/capturedLetConstInLoop4.js b/tests/baselines/reference/capturedLetConstInLoop4.js
index e3587ad64c6a3..2cade08f0a6d6 100644
--- a/tests/baselines/reference/capturedLetConstInLoop4.js
+++ b/tests/baselines/reference/capturedLetConstInLoop4.js
@@ -151,13 +151,13 @@ System.register([], function (exports_1, context_1) {
     function exportedFoo() {
         return v0 + v00 + v1 + v2 + v3 + v4 + v5 + v6 + v7 + v8;
     }
+    exports_1("exportedFoo", exportedFoo);
     //======const
     function exportedFoo2() {
         return v0_c + v00_c + v1_c + v2_c + v3_c + v4_c + v5_c + v6_c + v7_c + v8_c;
     }
-    var v0, v00, v1, v2, v3, v4, v5, v6, v7, v8, v0_c, v00_c, v1_c, v2_c, v3_c, v4_c, v5_c, v6_c, v7_c, v8_c;
-    exports_1("exportedFoo", exportedFoo);
     exports_1("exportedFoo2", exportedFoo2);
+    var v0, v00, v1, v2, v3, v4, v5, v6, v7, v8, v0_c, v00_c, v1_c, v2_c, v3_c, v4_c, v5_c, v6_c, v7_c, v8_c;
     return {
         setters: [],
         execute: function () {
diff --git a/tests/baselines/reference/dottedNamesInSystem.js b/tests/baselines/reference/dottedNamesInSystem.js
index e337e8cb1238a..257d7e616afe8 100644
--- a/tests/baselines/reference/dottedNamesInSystem.js
+++ b/tests/baselines/reference/dottedNamesInSystem.js
@@ -14,8 +14,8 @@ System.register([], function (exports_1, context_1) {
     function bar() {
         return A.B.C.foo();
     }
-    var A;
     exports_1("bar", bar);
+    var A;
     return {
         setters: [],
         execute: function () {
diff --git a/tests/baselines/reference/outFilerootDirModuleNamesSystem.js b/tests/baselines/reference/outFilerootDirModuleNamesSystem.js
index 6754f3ef89a29..efc49f9020962 100644
--- a/tests/baselines/reference/outFilerootDirModuleNamesSystem.js
+++ b/tests/baselines/reference/outFilerootDirModuleNamesSystem.js
@@ -15,8 +15,8 @@ System.register("b", ["a"], function (exports_1, context_1) {
     "use strict";
     var __moduleName = context_1 && context_1.id;
     function foo() { new a_1.default(); }
-    var a_1;
     exports_1("default", foo);
+    var a_1;
     return {
         setters: [
             function (a_1_1) {
diff --git a/tests/baselines/reference/systemModule10.js b/tests/baselines/reference/systemModule10.js
index 10afa784ebb8b..a54afee15d79e 100644
--- a/tests/baselines/reference/systemModule10.js
+++ b/tests/baselines/reference/systemModule10.js
@@ -24,10 +24,10 @@ System.register(["file1", "file2"], function (exports_1, context_1) {
             }
         ],
         execute: function () {
-            exports_1("x", file1_1.x);
-            exports_1("y", file1_1.x);
             exports_1("n", file1_1["default"]);
             exports_1("n1", file1_1["default"]);
+            exports_1("x", file1_1.x);
+            exports_1("y", file1_1.x);
             exports_1("n2", n2);
             exports_1("n3", n2);
         }
diff --git a/tests/baselines/reference/systemModule10_ES5.js b/tests/baselines/reference/systemModule10_ES5.js
index 830c611bd3886..bac2a6003a421 100644
--- a/tests/baselines/reference/systemModule10_ES5.js
+++ b/tests/baselines/reference/systemModule10_ES5.js
@@ -24,10 +24,10 @@ System.register(["file1", "file2"], function (exports_1, context_1) {
             }
         ],
         execute: function () {
-            exports_1("x", file1_1.x);
-            exports_1("y", file1_1.x);
             exports_1("n", file1_1.default);
             exports_1("n1", file1_1.default);
+            exports_1("x", file1_1.x);
+            exports_1("y", file1_1.x);
             exports_1("n2", n2);
             exports_1("n3", n2);
         }
diff --git a/tests/baselines/reference/systemModule11.js b/tests/baselines/reference/systemModule11.js
index 7f120cec40d25..41574af1d9aa5 100644
--- a/tests/baselines/reference/systemModule11.js
+++ b/tests/baselines/reference/systemModule11.js
@@ -46,8 +46,8 @@ System.register(["bar"], function (exports_1, context_1) {
     "use strict";
     var __moduleName = context_1 && context_1.id;
     function foo() { }
-    var x;
     exports_1("foo", foo);
+    var x;
     var exportedNames_1 = {
         "x": true,
         "foo": true
@@ -95,8 +95,6 @@ System.register(["bar"], function (exports_1, context_1) {
             }
         ],
         execute: function () {
-            exports_1("x", x);
-            exports_1("y1", y);
         }
     };
 });
@@ -139,10 +137,10 @@ System.register(["a"], function (exports_1, context_1) {
     "use strict";
     var __moduleName = context_1 && context_1.id;
     function foo() { }
-    function default_1() { }
-    var x, z, z1;
     exports_1("foo", foo);
+    function default_1() { }
     exports_1("default", default_1);
+    var x, z, z1;
     return {
         setters: [
             function (a_1_1) {
@@ -153,8 +151,6 @@ System.register(["a"], function (exports_1, context_1) {
             }
         ],
         execute: function () {
-            exports_1("z", z);
-            exports_1("z2", z1);
         }
     };
 });
diff --git a/tests/baselines/reference/systemModule13.js b/tests/baselines/reference/systemModule13.js
index c527fd3e81183..d3fee049e0490 100644
--- a/tests/baselines/reference/systemModule13.js
+++ b/tests/baselines/reference/systemModule13.js
@@ -8,12 +8,12 @@ for ([x] of [[1]]) {}
 System.register([], function (exports_1, context_1) {
     "use strict";
     var __moduleName = context_1 && context_1.id;
-    var x, y, z, _a, z0, z1, _b;
+    var x, y, z, z0, z1, _a, _b;
     return {
         setters: [],
         execute: function () {
-            _a = [1, 2, 3], exports_1("x", x = _a[0]), exports_1("y", y = _a[1]), exports_1("z", z = _a[2]);
-            _b = { a: true, b: { c: "123" } }, exports_1("z0", z0 = _b.a), exports_1("z1", z1 = _b.b.c);
+            exports_1("x", x = (_a = [1, 2, 3], _a[0])), exports_1("y", y = _a[1]), exports_1("z", z = _a[2]);
+            exports_1("z0", z0 = (_b = { a: true, b: { c: "123" } }, _b.a)), exports_1("z1", z1 = _b.b.c);
             for (var _i = 0, _a = [[1]]; _i < _a.length; _i++) {
                 exports_1("x", x = _a[_i][0]);
             }
diff --git a/tests/baselines/reference/systemModule14.js b/tests/baselines/reference/systemModule14.js
index bebe9244e0731..ba4adc7aabcef 100644
--- a/tests/baselines/reference/systemModule14.js
+++ b/tests/baselines/reference/systemModule14.js
@@ -17,6 +17,8 @@ System.register(["foo"], function (exports_1, context_1) {
     function foo() {
         return foo_1.a;
     }
+    exports_1("foo", foo);
+    exports_1("b", foo);
     var foo_1, x;
     return {
         setters: [
@@ -25,9 +27,7 @@ System.register(["foo"], function (exports_1, context_1) {
             }
         ],
         execute: function () {
-            exports_1("foo", foo);
             x = 1;
-            exports_1("b", foo);
         }
     };
 });
diff --git a/tests/baselines/reference/systemModule17.js b/tests/baselines/reference/systemModule17.js
index df3d722f3d23c..bcdf661235639 100644
--- a/tests/baselines/reference/systemModule17.js
+++ b/tests/baselines/reference/systemModule17.js
@@ -71,18 +71,18 @@ System.register(["f1"], function (exports_1, context_1) {
         ],
         execute: function () {
             x = 1;
+            exports_1("x", x);
+            exports_1("x1", x);
             (function (N) {
                 N.x = 1;
             })(N || (N = {}));
             IX = N.x;
-            exports_1("x", x);
-            exports_1("x1", x);
+            exports_1("IX", IX);
+            exports_1("IX1", IX);
             exports_1("A", f1_1.A);
             exports_1("A1", f1_1.A);
             exports_1("EA", f1_1.A);
             exports_1("EA1", f1_1.A);
-            exports_1("IX", IX);
-            exports_1("IX1", IX);
         }
     };
 });
diff --git a/tests/baselines/reference/systemModule3.js b/tests/baselines/reference/systemModule3.js
index a8f93941c89d8..109cbb7187cf3 100644
--- a/tests/baselines/reference/systemModule3.js
+++ b/tests/baselines/reference/systemModule3.js
@@ -67,9 +67,9 @@ System.register([], function (exports_1, context_1) {
         setters: [],
         execute: function () {
             default_1 = (function () {
-                function class_1() {
+                function default_1() {
                 }
-                return class_1;
+                return default_1;
             }());
             exports_1("default", default_1);
         }
diff --git a/tests/baselines/reference/systemModule8.js b/tests/baselines/reference/systemModule8.js
index 467c52298fb33..3065d4f35b301 100644
--- a/tests/baselines/reference/systemModule8.js
+++ b/tests/baselines/reference/systemModule8.js
@@ -62,7 +62,7 @@ System.register([], function (exports_1, context_1) {
             for (exports_1("x", x = 18);; exports_1("x", --x)) { }
             for (var x_1 = 50;;) { }
             exports_1("y", y = [1][0]);
-            _a = { a: true, b: { c: "123" } }, exports_1("z0", z0 = _a.a), exports_1("z1", z1 = _a.b.c);
+            exports_1("z0", z0 = (_a = { a: true, b: { c: "123" } }, _a.a)), exports_1("z1", z1 = _a.b.c);
             for (var _i = 0, _a = [[1]]; _i < _a.length; _i++) {
                 exports_1("x", x = _a[_i][0]);
             }
diff --git a/tests/baselines/reference/systemModule9.js b/tests/baselines/reference/systemModule9.js
index e46b97a71a272..9e497140083ec 100644
--- a/tests/baselines/reference/systemModule9.js
+++ b/tests/baselines/reference/systemModule9.js
@@ -70,7 +70,6 @@ System.register(["file1", "file2", "file3", "file4", "file5", "file6", "file7"],
             ns2.f();
             ns3.f();
             y = true;
-            exports_1("x", x);
             exports_1("z", y);
         }
     };
diff --git a/tests/baselines/reference/systemModuleConstEnumsSeparateCompilation.js b/tests/baselines/reference/systemModuleConstEnumsSeparateCompilation.js
index ca68d952ab3ab..132d27a4ea03c 100644
--- a/tests/baselines/reference/systemModuleConstEnumsSeparateCompilation.js
+++ b/tests/baselines/reference/systemModuleConstEnumsSeparateCompilation.js
@@ -20,8 +20,8 @@ System.register([], function (exports_1, context_1) {
         use(TopLevelConstEnum.X);
         use(M.NonTopLevelConstEnum.X);
     }
-    var TopLevelConstEnum, M;
     exports_1("foo", foo);
+    var TopLevelConstEnum, M;
     return {
         setters: [],
         execute: function () {
diff --git a/tests/baselines/reference/systemModuleDeclarationMerging.js b/tests/baselines/reference/systemModuleDeclarationMerging.js
index 27cdd9f157274..d60a315b0a67b 100644
--- a/tests/baselines/reference/systemModuleDeclarationMerging.js
+++ b/tests/baselines/reference/systemModuleDeclarationMerging.js
@@ -14,8 +14,8 @@ System.register([], function (exports_1, context_1) {
     "use strict";
     var __moduleName = context_1 && context_1.id;
     function F() { }
-    var C, E;
     exports_1("F", F);
+    var C, E;
     return {
         setters: [],
         execute: function () {
diff --git a/tests/baselines/reference/systemModuleExportDefault.js b/tests/baselines/reference/systemModuleExportDefault.js
index 53f63ecb027e2..67341a04a0b92 100644
--- a/tests/baselines/reference/systemModuleExportDefault.js
+++ b/tests/baselines/reference/systemModuleExportDefault.js
@@ -48,9 +48,9 @@ System.register([], function (exports_1, context_1) {
         setters: [],
         execute: function () {
             default_1 = (function () {
-                function class_1() {
+                function default_1() {
                 }
-                return class_1;
+                return default_1;
             }());
             exports_1("default", default_1);
         }
diff --git a/tests/baselines/reference/systemModuleNonTopLevelModuleMembers.js b/tests/baselines/reference/systemModuleNonTopLevelModuleMembers.js
index c6d3c8295e01f..df68f32b3bd73 100644
--- a/tests/baselines/reference/systemModuleNonTopLevelModuleMembers.js
+++ b/tests/baselines/reference/systemModuleNonTopLevelModuleMembers.js
@@ -17,8 +17,8 @@ System.register([], function (exports_1, context_1) {
     "use strict";
     var __moduleName = context_1 && context_1.id;
     function TopLevelFunction() { }
-    var TopLevelClass, TopLevelModule, TopLevelEnum, TopLevelModule2;
     exports_1("TopLevelFunction", TopLevelFunction);
+    var TopLevelClass, TopLevelModule, TopLevelEnum, TopLevelModule2;
     return {
         setters: [],
         execute: function () {
diff --git a/tests/baselines/reference/systemModuleTargetES6.js b/tests/baselines/reference/systemModuleTargetES6.js
index a049ea78395b6..2fe48f4c57b5d 100644
--- a/tests/baselines/reference/systemModuleTargetES6.js
+++ b/tests/baselines/reference/systemModuleTargetES6.js
@@ -20,12 +20,12 @@ System.register([], function (exports_1, context_1) {
     function myFunction() {
         return new MyClass();
     }
+    exports_1("myFunction", myFunction);
     function myFunction2() {
         return new MyClass2();
     }
-    var MyClass, MyClass2;
-    exports_1("myFunction", myFunction);
     exports_1("myFunction2", myFunction2);
+    var MyClass, MyClass2;
     return {
         setters: [],
         execute: function () {
@@ -35,8 +35,8 @@ System.register([], function (exports_1, context_1) {
             MyClass2 = class MyClass2 {
                 static getInstance() { return MyClass2.value; }
             };
-            exports_1("MyClass2", MyClass2);
             MyClass2.value = 42;
+            exports_1("MyClass2", MyClass2);
         }
     };
 });

From 35acd00fdb0a83861e1d94e2ab7cf730e0eb2ede Mon Sep 17 00:00:00 2001
From: Ron Buckton <rbuckton@microsoft.com>
Date: Thu, 20 Oct 2016 17:15:23 -0700
Subject: [PATCH 066/224] Update baseline

---
 .../reference/variableDeclarationInStrictMode1.errors.txt       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
index 46782aaa1d69d..9dd9a8d41a1bf 100644
--- a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
+++ b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
@@ -1,4 +1,4 @@
-lib.d.ts(32,18): error TS2300: Duplicate identifier 'eval'.
+lib.d.ts(28,18): error TS2300: Duplicate identifier 'eval'.
 tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS1100: Invalid use of 'eval' in strict mode.
 tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS2300: Duplicate identifier 'eval'.
 

From 82c300ab98052b5f5d99e8be0511cc0cb9aeb90e Mon Sep 17 00:00:00 2001
From: Ron Buckton <rbuckton@microsoft.com>
Date: Thu, 20 Oct 2016 17:26:58 -0700
Subject: [PATCH 067/224] Revert baseline change due to stale output

---
 .../reference/variableDeclarationInStrictMode1.errors.txt       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
index 9dd9a8d41a1bf..46782aaa1d69d 100644
--- a/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
+++ b/tests/baselines/reference/variableDeclarationInStrictMode1.errors.txt
@@ -1,4 +1,4 @@
-lib.d.ts(28,18): error TS2300: Duplicate identifier 'eval'.
+lib.d.ts(32,18): error TS2300: Duplicate identifier 'eval'.
 tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS1100: Invalid use of 'eval' in strict mode.
 tests/cases/compiler/variableDeclarationInStrictMode1.ts(2,5): error TS2300: Duplicate identifier 'eval'.
 

From ce61b341599263f2caf68f34c644038f410ddb76 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 21 Oct 2016 10:53:19 -0700
Subject: [PATCH 068/224] Resolve all-object intersections inside spreads

This means that getSpreadType will return an object type, even when
spreading two intersections, as long as those intersections contain
nothing but object types themselves.
---
 src/compiler/checker.ts | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index bf81d64ea0622..5da7cc7e66786 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5828,13 +5828,16 @@ namespace ts {
                 types.push(rspread.right);
                 return getSpreadType(types, symbol, aliasSymbol, aliasTypeArguments);
             }
+            if (right.flags & TypeFlags.Intersection) {
+                right = resolveObjectIntersection(right as IntersectionType);
+            }
             if (right.flags & TypeFlags.Union) {
                 const spreads = map((right as UnionType).types,
                                     t => getSpreadType(types.slice().concat([t]), symbol, aliasSymbol, aliasTypeArguments));
                 return getUnionType(spreads, /*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
             }
             const atBeginning = types.length === 0;
-            const left = getSpreadType(types, symbol, aliasSymbol, aliasTypeArguments);
+            let left = getSpreadType(types, symbol, aliasSymbol, aliasTypeArguments);
             if (right.flags & (TypeFlags.Primitive & ~TypeFlags.StringLike) || left.flags & TypeFlags.Any) {
                 return left;
             }
@@ -5853,6 +5856,9 @@ namespace ts {
                 const simplified = getSpreadType([right, (left as SpreadType).right], symbol, aliasSymbol, aliasTypeArguments);
                 return getSpreadType([(left as SpreadType).left, simplified], symbol, aliasSymbol, aliasTypeArguments);
             }
+            if (left.flags & TypeFlags.Intersection) {
+                left = resolveObjectIntersection(left as IntersectionType);
+            }
             if (left.flags & TypeFlags.Union) {
                 const spreads = map((left as UnionType).types,
                                   t => getSpreadType(types.slice().concat([t, right]), symbol, aliasSymbol, aliasTypeArguments));
@@ -5917,6 +5923,20 @@ namespace ts {
             return spread;
         }
 
+        function resolveObjectIntersection(intersection: IntersectionType): IntersectionType | ResolvedType {
+            if (find(intersection.types, t => !(t.flags & TypeFlags.ObjectType && !couldContainTypeParameters(t)))) {
+                return intersection;
+            }
+            const properties = getPropertiesOfType(intersection);
+            const members = createMap<Symbol>();
+            for (const property of properties) {
+                members[property.name] = property;
+            }
+            const stringIndex = getIndexInfoOfType(intersection, IndexKind.String);
+            const numberIndex = getIndexInfoOfType(intersection, IndexKind.Number);
+            return createAnonymousType(undefined, members, emptyArray, emptyArray, stringIndex, numberIndex);
+        }
+
         function createLiteralType(flags: TypeFlags, text: string) {
             const type = <LiteralType>createType(flags);
             type.text = text;

From 422f73b1a99eedc80dd70a7d97c49467b05172e3 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 21 Oct 2016 10:54:53 -0700
Subject: [PATCH 069/224] Update and improve spread intersection tests

---
 .../reference/objectSpreadIntersection.js     |  12 +-
 .../objectSpreadIntersection.symbols          | 181 ++++++++++--------
 .../reference/objectSpreadIntersection.types  |  37 +++-
 .../types/spread/objectSpreadIntersection.ts  |   8 +-
 4 files changed, 146 insertions(+), 92 deletions(-)

diff --git a/tests/baselines/reference/objectSpreadIntersection.js b/tests/baselines/reference/objectSpreadIntersection.js
index d86b7bfca584c..2ec6ad35413a3 100644
--- a/tests/baselines/reference/objectSpreadIntersection.js
+++ b/tests/baselines/reference/objectSpreadIntersection.js
@@ -8,10 +8,14 @@ function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
 // concrete types work
 interface A1 { a: number }
 interface A2 { a: string }
+interface B1 { b: number }
+interface B2 { b: string }
 let a12: A1 & A2;
-let result = { ...a12 };
+let b12: B1 & B2;
+let result = { ...a12, ...b12 };
 let sn: number & string = result.a;
-let assignable: { ...(A1 & A2) } = result;
+sn = result.b;
+let assignable: { ...(A1 & A2), ...(B1 & B2) } = result;
 
 function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tuv: T & U & V;
@@ -49,8 +53,10 @@ function iteratedUnionIntersection(t, u, v) {
     var assignable = result;
 }
 var a12;
-var result = __assign({}, a12);
+var b12;
+var result = __assign({}, a12, b12);
 var sn = result.a;
+sn = result.b;
 var assignable = result;
 function tripleIntersection(t, u, v) {
     var tuv;
diff --git a/tests/baselines/reference/objectSpreadIntersection.symbols b/tests/baselines/reference/objectSpreadIntersection.symbols
index 6dd27645ddf13..bc63cb11348e4 100644
--- a/tests/baselines/reference/objectSpreadIntersection.symbols
+++ b/tests/baselines/reference/objectSpreadIntersection.symbols
@@ -43,125 +43,146 @@ interface A2 { a: string }
 >A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 7, 26))
 >a : Symbol(A2.a, Decl(objectSpreadIntersection.ts, 8, 14))
 
+interface B1 { b: number }
+>B1 : Symbol(B1, Decl(objectSpreadIntersection.ts, 8, 26))
+>b : Symbol(B1.b, Decl(objectSpreadIntersection.ts, 9, 14))
+
+interface B2 { b: string }
+>B2 : Symbol(B2, Decl(objectSpreadIntersection.ts, 9, 26))
+>b : Symbol(B2.b, Decl(objectSpreadIntersection.ts, 10, 14))
+
 let a12: A1 & A2;
->a12 : Symbol(a12, Decl(objectSpreadIntersection.ts, 9, 3))
+>a12 : Symbol(a12, Decl(objectSpreadIntersection.ts, 11, 3))
 >A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 5, 1))
 >A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 7, 26))
 
-let result = { ...a12 };
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 10, 3))
+let b12: B1 & B2;
+>b12 : Symbol(b12, Decl(objectSpreadIntersection.ts, 12, 3))
+>B1 : Symbol(B1, Decl(objectSpreadIntersection.ts, 8, 26))
+>B2 : Symbol(B2, Decl(objectSpreadIntersection.ts, 9, 26))
+
+let result = { ...a12, ...b12 };
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 13, 3))
 
 let sn: number & string = result.a;
->sn : Symbol(sn, Decl(objectSpreadIntersection.ts, 11, 3))
+>sn : Symbol(sn, Decl(objectSpreadIntersection.ts, 14, 3))
 >result.a : Symbol(a, Decl(objectSpreadIntersection.ts, 7, 14), Decl(objectSpreadIntersection.ts, 8, 14))
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 10, 3))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 13, 3))
 >a : Symbol(a, Decl(objectSpreadIntersection.ts, 7, 14), Decl(objectSpreadIntersection.ts, 8, 14))
 
-let assignable: { ...(A1 & A2) } = result;
->assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 12, 3))
+sn = result.b;
+>sn : Symbol(sn, Decl(objectSpreadIntersection.ts, 14, 3))
+>result.b : Symbol(b, Decl(objectSpreadIntersection.ts, 9, 14), Decl(objectSpreadIntersection.ts, 10, 14))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 13, 3))
+>b : Symbol(b, Decl(objectSpreadIntersection.ts, 9, 14), Decl(objectSpreadIntersection.ts, 10, 14))
+
+let assignable: { ...(A1 & A2), ...(B1 & B2) } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 16, 3))
 >A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 5, 1))
 >A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 7, 26))
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 10, 3))
+>B1 : Symbol(B1, Decl(objectSpreadIntersection.ts, 8, 26))
+>B2 : Symbol(B2, Decl(objectSpreadIntersection.ts, 9, 26))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 13, 3))
 
 function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
->tripleIntersection : Symbol(tripleIntersection, Decl(objectSpreadIntersection.ts, 12, 42))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 14, 28))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 14, 30))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 14, 33))
->t : Symbol(t, Decl(objectSpreadIntersection.ts, 14, 37))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 14, 28))
->u : Symbol(u, Decl(objectSpreadIntersection.ts, 14, 42))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 14, 30))
->v : Symbol(v, Decl(objectSpreadIntersection.ts, 14, 48))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 14, 33))
+>tripleIntersection : Symbol(tripleIntersection, Decl(objectSpreadIntersection.ts, 16, 56))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 18, 28))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 18, 30))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 18, 33))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 18, 37))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 18, 28))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 18, 42))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 18, 30))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 18, 48))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 18, 33))
 
     let tuv: T & U & V;
->tuv : Symbol(tuv, Decl(objectSpreadIntersection.ts, 15, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 14, 28))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 14, 30))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 14, 33))
+>tuv : Symbol(tuv, Decl(objectSpreadIntersection.ts, 19, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 18, 28))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 18, 30))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 18, 33))
 
     let result = { ...tuv, id: 'bar' };
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 16, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 16, 26))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 20, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 20, 26))
 
     let assignable: { ...(T & U & V), id: string } = result;
->assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 17, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 14, 28))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 14, 30))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 14, 33))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 17, 37))
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 16, 7))
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 21, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 18, 28))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 18, 30))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 18, 33))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 21, 37))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 20, 7))
 }
 function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
->iteratedDoubleIntersection : Symbol(iteratedDoubleIntersection, Decl(objectSpreadIntersection.ts, 18, 1))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 19, 36))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 19, 38))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 19, 41))
->t : Symbol(t, Decl(objectSpreadIntersection.ts, 19, 45))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 19, 36))
->u : Symbol(u, Decl(objectSpreadIntersection.ts, 19, 50))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 19, 38))
->v : Symbol(v, Decl(objectSpreadIntersection.ts, 19, 56))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 19, 41))
+>iteratedDoubleIntersection : Symbol(iteratedDoubleIntersection, Decl(objectSpreadIntersection.ts, 22, 1))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 23, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 23, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 23, 41))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 23, 45))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 23, 36))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 23, 50))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 23, 38))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 23, 56))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 23, 41))
 
     let tu: T & U;
->tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 20, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 19, 36))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 19, 38))
+>tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 24, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 23, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 23, 38))
 
     let uv: U & V;
->uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 21, 7))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 19, 38))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 19, 41))
+>uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 25, 7))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 23, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 23, 41))
 
     let result = { ...tu, ...uv, id: 'baz' };
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 22, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 22, 32))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 26, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 26, 32))
 
     let assignable: { ...(T & U), ...(U & V), id: string } = result;
->assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 23, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 19, 36))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 19, 38))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 19, 38))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 19, 41))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 23, 45))
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 22, 7))
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 27, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 23, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 23, 38))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 23, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 23, 41))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 27, 45))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 26, 7))
 }
 function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
->iteratedIntersectionUnion : Symbol(iteratedIntersectionUnion, Decl(objectSpreadIntersection.ts, 24, 1))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 25, 35))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 25, 37))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 25, 40))
->t : Symbol(t, Decl(objectSpreadIntersection.ts, 25, 44))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 25, 35))
->u : Symbol(u, Decl(objectSpreadIntersection.ts, 25, 49))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 25, 37))
->v : Symbol(v, Decl(objectSpreadIntersection.ts, 25, 55))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 25, 40))
+>iteratedIntersectionUnion : Symbol(iteratedIntersectionUnion, Decl(objectSpreadIntersection.ts, 28, 1))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 29, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 29, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 29, 40))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 29, 44))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 29, 35))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 29, 49))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 29, 37))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 29, 55))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 29, 40))
 
     let tu: T & U;
->tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 26, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 25, 35))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 25, 37))
+>tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 30, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 29, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 29, 37))
 
     let uv: U | V;
->uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 27, 7))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 25, 37))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 25, 40))
+>uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 31, 7))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 29, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 29, 40))
 
     let result = { ...tu, ...uv, id: 'qux' };
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 28, 7))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 28, 32))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 32, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 32))
 
     let assignable: { ...(T & U), ...(U | V), id: string } = result;
->assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 29, 7))
->T : Symbol(T, Decl(objectSpreadIntersection.ts, 25, 35))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 25, 37))
->U : Symbol(U, Decl(objectSpreadIntersection.ts, 25, 37))
->V : Symbol(V, Decl(objectSpreadIntersection.ts, 25, 40))
->id : Symbol(id, Decl(objectSpreadIntersection.ts, 29, 45))
->result : Symbol(result, Decl(objectSpreadIntersection.ts, 28, 7))
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 33, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 29, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 29, 37))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 29, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 29, 40))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 33, 45))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 32, 7))
 }
 
 
diff --git a/tests/baselines/reference/objectSpreadIntersection.types b/tests/baselines/reference/objectSpreadIntersection.types
index 0e21f42a76bea..13c1384698f08 100644
--- a/tests/baselines/reference/objectSpreadIntersection.types
+++ b/tests/baselines/reference/objectSpreadIntersection.types
@@ -47,27 +47,50 @@ interface A2 { a: string }
 >A2 : A2
 >a : string
 
+interface B1 { b: number }
+>B1 : B1
+>b : number
+
+interface B2 { b: string }
+>B2 : B2
+>b : string
+
 let a12: A1 & A2;
 >a12 : A1 & A2
 >A1 : A1
 >A2 : A2
 
-let result = { ...a12 };
->result : { ...A1 & A2 }
->{ ...a12 } : { ...A1 & A2 }
+let b12: B1 & B2;
+>b12 : B1 & B2
+>B1 : B1
+>B2 : B2
+
+let result = { ...a12, ...b12 };
+>result : { b: number & string; a: number & string; }
+>{ ...a12, ...b12 } : { b: number & string; a: number & string; }
 >a12 : any
+>b12 : any
 
 let sn: number & string = result.a;
 >sn : number & string
 >result.a : number & string
->result : { ...A1 & A2 }
+>result : { b: number & string; a: number & string; }
 >a : number & string
 
-let assignable: { ...(A1 & A2) } = result;
->assignable : { ...A1 & A2 }
+sn = result.b;
+>sn = result.b : number & string
+>sn : number & string
+>result.b : number & string
+>result : { b: number & string; a: number & string; }
+>b : number & string
+
+let assignable: { ...(A1 & A2), ...(B1 & B2) } = result;
+>assignable : { b: number & string; a: number & string; }
 >A1 : A1
 >A2 : A2
->result : { ...A1 & A2 }
+>B1 : B1
+>B2 : B2
+>result : { b: number & string; a: number & string; }
 
 function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
 >tripleIntersection : <T, U, V>(t: T, u: U, v: V) => void
diff --git a/tests/cases/conformance/types/spread/objectSpreadIntersection.ts b/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
index 636283dd71545..3bedacca89fac 100644
--- a/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
@@ -7,10 +7,14 @@ function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
 // concrete types work
 interface A1 { a: number }
 interface A2 { a: string }
+interface B1 { b: number }
+interface B2 { b: string }
 let a12: A1 & A2;
-let result = { ...a12 };
+let b12: B1 & B2;
+let result = { ...a12, ...b12 };
 let sn: number & string = result.a;
-let assignable: { ...(A1 & A2) } = result;
+sn = result.b;
+let assignable: { ...(A1 & A2), ...(B1 & B2) } = result;
 
 function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
     let tuv: T & U & V;

From fdfb159024047fff8980391653cda6419046fa36 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 21 Oct 2016 13:38:24 -0700
Subject: [PATCH 070/224] Simplify expression in resolveObjectIntersection

---
 src/compiler/checker.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 5da7cc7e66786..9df086f1bb70f 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5924,7 +5924,7 @@ namespace ts {
         }
 
         function resolveObjectIntersection(intersection: IntersectionType): IntersectionType | ResolvedType {
-            if (find(intersection.types, t => !(t.flags & TypeFlags.ObjectType && !couldContainTypeParameters(t)))) {
+            if (find(intersection.types, t => !(t.flags & TypeFlags.ObjectType) || couldContainTypeParameters(t))) {
                 return intersection;
             }
             const properties = getPropertiesOfType(intersection);

From ff92afd47bd6a5295cd84e129fea7212f65e3283 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 21 Oct 2016 16:27:32 -0700
Subject: [PATCH 071/224] Update baselines with new index signature rules

---
 tests/baselines/reference/objectSpread.js     |   7 +-
 .../baselines/reference/objectSpread.symbols  | 239 +++++++++---------
 tests/baselines/reference/objectSpread.types  |   7 +-
 .../objectSpreadIndexSignature.errors.txt     |  35 +++
 .../reference/objectSpreadIndexSignature.js   |   2 +
 .../objectSpreadIndexSignature.symbols        |  83 ------
 .../objectSpreadIndexSignature.types          |  91 -------
 .../reference/objectSpreadIntersection.types  |   8 +-
 .../reference/objectSpreadNegative.errors.txt |   8 +-
 .../reference/objectSpreadUnion.types         |   8 +-
 .../conformance/types/spread/objectSpread.ts  |   4 +-
 .../spread/objectSpreadIndexSignature.ts      |   1 +
 12 files changed, 175 insertions(+), 318 deletions(-)
 create mode 100644 tests/baselines/reference/objectSpreadIndexSignature.errors.txt
 delete mode 100644 tests/baselines/reference/objectSpreadIndexSignature.symbols
 delete mode 100644 tests/baselines/reference/objectSpreadIndexSignature.types

diff --git a/tests/baselines/reference/objectSpread.js b/tests/baselines/reference/objectSpread.js
index 359284f9c6c51..23729d4cd6f21 100644
--- a/tests/baselines/reference/objectSpread.js
+++ b/tests/baselines/reference/objectSpread.js
@@ -35,14 +35,12 @@ let getter: { a: number, c: number } =
     { ...op, c: 7 }
 getter.a = 12;
 
-// null, undefined, functions and primitives besides string result in { }
+// null, undefined, functions and primitives result in { }
 let spreadNull = { ...null };
 let spreadUndefind = { ...undefined };
 let spreadNum = { ...12 };
 let spreadBool = { ...false };
 let spreadFunc = { ...(function () { }) };
-
-// strings get a numeric indexer: [n: number]: string
 let spreadStr = { ...'foo' };
 
 // methods are not enumerable
@@ -130,13 +128,12 @@ var propertyNested = __assign({ a: __assign({}, o) });
 var op = { get a() { return 6; } };
 var getter = __assign({}, op, { c: 7 });
 getter.a = 12;
-// null, undefined, functions and primitives besides string result in { }
+// null, undefined, functions and primitives result in { }
 var spreadNull = __assign({}, null);
 var spreadUndefind = __assign({}, undefined);
 var spreadNum = __assign({}, 12);
 var spreadBool = __assign({}, false);
 var spreadFunc = __assign({}, (function () { }));
-// strings get a numeric indexer: [n: number]: string
 var spreadStr = __assign({}, 'foo');
 // methods are not enumerable
 var C = (function () {
diff --git a/tests/baselines/reference/objectSpread.symbols b/tests/baselines/reference/objectSpread.symbols
index fb7a1e22b33f3..039be9e0d7df5 100644
--- a/tests/baselines/reference/objectSpread.symbols
+++ b/tests/baselines/reference/objectSpread.symbols
@@ -150,7 +150,7 @@ getter.a = 12;
 >getter : Symbol(getter, Decl(objectSpread.ts, 32, 3))
 >a : Symbol(a, Decl(objectSpread.ts, 32, 13))
 
-// null, undefined, functions and primitives besides string result in { }
+// null, undefined, functions and primitives result in { }
 let spreadNull = { ...null };
 >spreadNull : Symbol(spreadNull, Decl(objectSpread.ts, 37, 3))
 
@@ -166,209 +166,208 @@ let spreadBool = { ...false };
 let spreadFunc = { ...(function () { }) };
 >spreadFunc : Symbol(spreadFunc, Decl(objectSpread.ts, 41, 3))
 
-// strings get a numeric indexer: [n: number]: string
 let spreadStr = { ...'foo' };
->spreadStr : Symbol(spreadStr, Decl(objectSpread.ts, 44, 3))
+>spreadStr : Symbol(spreadStr, Decl(objectSpread.ts, 42, 3))
 
 // methods are not enumerable
 class C { p = 1; m() { } }
->C : Symbol(C, Decl(objectSpread.ts, 44, 29))
->p : Symbol(C.p, Decl(objectSpread.ts, 47, 9))
->m : Symbol(C.m, Decl(objectSpread.ts, 47, 16))
+>C : Symbol(C, Decl(objectSpread.ts, 42, 29))
+>p : Symbol(C.p, Decl(objectSpread.ts, 45, 9))
+>m : Symbol(C.m, Decl(objectSpread.ts, 45, 16))
 
 let c: C = new C()
->c : Symbol(c, Decl(objectSpread.ts, 48, 3))
->C : Symbol(C, Decl(objectSpread.ts, 44, 29))
->C : Symbol(C, Decl(objectSpread.ts, 44, 29))
+>c : Symbol(c, Decl(objectSpread.ts, 46, 3))
+>C : Symbol(C, Decl(objectSpread.ts, 42, 29))
+>C : Symbol(C, Decl(objectSpread.ts, 42, 29))
 
 let spreadC: { p: number } = { ...c }
->spreadC : Symbol(spreadC, Decl(objectSpread.ts, 49, 3))
->p : Symbol(p, Decl(objectSpread.ts, 49, 14))
+>spreadC : Symbol(spreadC, Decl(objectSpread.ts, 47, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 47, 14))
 
 // own methods are enumerable
 let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } };
->cplus : Symbol(cplus, Decl(objectSpread.ts, 52, 3))
->p : Symbol(p, Decl(objectSpread.ts, 52, 12))
->plus : Symbol(plus, Decl(objectSpread.ts, 52, 23))
->plus : Symbol(plus, Decl(objectSpread.ts, 52, 48))
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 50, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 50, 12))
+>plus : Symbol(plus, Decl(objectSpread.ts, 50, 23))
+>plus : Symbol(plus, Decl(objectSpread.ts, 50, 48))
 
 cplus.plus();
->cplus.plus : Symbol(plus, Decl(objectSpread.ts, 52, 23))
->cplus : Symbol(cplus, Decl(objectSpread.ts, 52, 3))
->plus : Symbol(plus, Decl(objectSpread.ts, 52, 23))
+>cplus.plus : Symbol(plus, Decl(objectSpread.ts, 50, 23))
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 50, 3))
+>plus : Symbol(plus, Decl(objectSpread.ts, 50, 23))
 
 // new field's type conflicting with existing field is OK
 let changeTypeAfter: { a: string, b: string } =
->changeTypeAfter : Symbol(changeTypeAfter, Decl(objectSpread.ts, 56, 3))
->a : Symbol(a, Decl(objectSpread.ts, 56, 22))
->b : Symbol(b, Decl(objectSpread.ts, 56, 33))
+>changeTypeAfter : Symbol(changeTypeAfter, Decl(objectSpread.ts, 54, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 54, 22))
+>b : Symbol(b, Decl(objectSpread.ts, 54, 33))
 
     { ...o, a: 'wrong type?' }
->a : Symbol(a, Decl(objectSpread.ts, 57, 11))
+>a : Symbol(a, Decl(objectSpread.ts, 55, 11))
 
 let changeTypeBefore: { a: number, b: string } =
->changeTypeBefore : Symbol(changeTypeBefore, Decl(objectSpread.ts, 58, 3))
->a : Symbol(a, Decl(objectSpread.ts, 58, 23))
->b : Symbol(b, Decl(objectSpread.ts, 58, 34))
+>changeTypeBefore : Symbol(changeTypeBefore, Decl(objectSpread.ts, 56, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 56, 23))
+>b : Symbol(b, Decl(objectSpread.ts, 56, 34))
 
     { a: 'wrong type?', ...o };
->a : Symbol(a, Decl(objectSpread.ts, 59, 5))
+>a : Symbol(a, Decl(objectSpread.ts, 57, 5))
 
 let changeTypeBoth: { a: string, b: number } =
->changeTypeBoth : Symbol(changeTypeBoth, Decl(objectSpread.ts, 60, 3))
->a : Symbol(a, Decl(objectSpread.ts, 60, 21))
->b : Symbol(b, Decl(objectSpread.ts, 60, 32))
+>changeTypeBoth : Symbol(changeTypeBoth, Decl(objectSpread.ts, 58, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 58, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 58, 32))
 
     { ...o, ...swap };
 
 // optional
 let definiteBoolean: { sn: boolean };
->definiteBoolean : Symbol(definiteBoolean, Decl(objectSpread.ts, 64, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 64, 22))
+>definiteBoolean : Symbol(definiteBoolean, Decl(objectSpread.ts, 62, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 62, 22))
 
 let definiteString: { sn: string };
->definiteString : Symbol(definiteString, Decl(objectSpread.ts, 65, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 65, 21))
+>definiteString : Symbol(definiteString, Decl(objectSpread.ts, 63, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 63, 21))
 
 let optionalString: { sn?: string };
->optionalString : Symbol(optionalString, Decl(objectSpread.ts, 66, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 66, 21))
+>optionalString : Symbol(optionalString, Decl(objectSpread.ts, 64, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 64, 21))
 
 let optionalNumber: { sn?: number };
->optionalNumber : Symbol(optionalNumber, Decl(objectSpread.ts, 67, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 67, 21))
+>optionalNumber : Symbol(optionalNumber, Decl(objectSpread.ts, 65, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 65, 21))
 
 let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
->optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpread.ts, 68, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 68, 25))
+>optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpread.ts, 66, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 66, 25))
 
 let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
->optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpread.ts, 69, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 69, 30))
+>optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpread.ts, 67, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 67, 30))
 
 let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
->allOptional : Symbol(allOptional, Decl(objectSpread.ts, 70, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 70, 18))
+>allOptional : Symbol(allOptional, Decl(objectSpread.ts, 68, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 68, 18))
 
 // computed property
 let computedFirst: { a: number, b: string, "before everything": number } =
->computedFirst : Symbol(computedFirst, Decl(objectSpread.ts, 73, 3))
->a : Symbol(a, Decl(objectSpread.ts, 73, 20))
->b : Symbol(b, Decl(objectSpread.ts, 73, 31))
+>computedFirst : Symbol(computedFirst, Decl(objectSpread.ts, 71, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 71, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 71, 31))
 
     { ['before everything']: 12, ...o, b: 'yes' }
->'before everything' : Symbol(['before everything'], Decl(objectSpread.ts, 74, 5))
->b : Symbol(b, Decl(objectSpread.ts, 74, 38))
+>'before everything' : Symbol(['before everything'], Decl(objectSpread.ts, 72, 5))
+>b : Symbol(b, Decl(objectSpread.ts, 72, 38))
 
 let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
->computedMiddle : Symbol(computedMiddle, Decl(objectSpread.ts, 75, 3))
->a : Symbol(a, Decl(objectSpread.ts, 75, 21))
->b : Symbol(b, Decl(objectSpread.ts, 75, 32))
->c : Symbol(c, Decl(objectSpread.ts, 75, 43))
+>computedMiddle : Symbol(computedMiddle, Decl(objectSpread.ts, 73, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 73, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 73, 32))
+>c : Symbol(c, Decl(objectSpread.ts, 73, 43))
 
     { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
->'in the middle' : Symbol(['in the middle'], Decl(objectSpread.ts, 76, 11))
->b : Symbol(b, Decl(objectSpread.ts, 76, 34))
+>'in the middle' : Symbol(['in the middle'], Decl(objectSpread.ts, 74, 11))
+>b : Symbol(b, Decl(objectSpread.ts, 74, 34))
 
 let computedAfter: { a: number, b: string, "at the end": number } =
->computedAfter : Symbol(computedAfter, Decl(objectSpread.ts, 77, 3))
->a : Symbol(a, Decl(objectSpread.ts, 77, 20))
->b : Symbol(b, Decl(objectSpread.ts, 77, 31))
+>computedAfter : Symbol(computedAfter, Decl(objectSpread.ts, 75, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 75, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 75, 31))
 
     { ...o, b: 'yeah', ['at the end']: 14 }
->b : Symbol(b, Decl(objectSpread.ts, 78, 11))
->'at the end' : Symbol(['at the end'], Decl(objectSpread.ts, 78, 22))
+>b : Symbol(b, Decl(objectSpread.ts, 76, 11))
+>'at the end' : Symbol(['at the end'], Decl(objectSpread.ts, 76, 22))
 
 // shortcut syntax
 let a = 12;
->a : Symbol(a, Decl(objectSpread.ts, 80, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 78, 3))
 
 let shortCutted: { a: number, b: string } = { ...o, a }
->shortCutted : Symbol(shortCutted, Decl(objectSpread.ts, 81, 3))
->a : Symbol(a, Decl(objectSpread.ts, 81, 18))
->b : Symbol(b, Decl(objectSpread.ts, 81, 29))
->a : Symbol(a, Decl(objectSpread.ts, 81, 51))
+>shortCutted : Symbol(shortCutted, Decl(objectSpread.ts, 79, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 79, 18))
+>b : Symbol(b, Decl(objectSpread.ts, 79, 29))
+>a : Symbol(a, Decl(objectSpread.ts, 79, 51))
 
 // generics
 function f<T, U>(t: T, u: U): { ...T, ...U, id: string } {
->f : Symbol(f, Decl(objectSpread.ts, 81, 55))
->T : Symbol(T, Decl(objectSpread.ts, 84, 11))
->U : Symbol(U, Decl(objectSpread.ts, 84, 13))
->t : Symbol(t, Decl(objectSpread.ts, 84, 17))
->T : Symbol(T, Decl(objectSpread.ts, 84, 11))
->u : Symbol(u, Decl(objectSpread.ts, 84, 22))
->U : Symbol(U, Decl(objectSpread.ts, 84, 13))
->T : Symbol(T, Decl(objectSpread.ts, 84, 11))
->U : Symbol(U, Decl(objectSpread.ts, 84, 13))
->id : Symbol(id, Decl(objectSpread.ts, 84, 43))
+>f : Symbol(f, Decl(objectSpread.ts, 79, 55))
+>T : Symbol(T, Decl(objectSpread.ts, 82, 11))
+>U : Symbol(U, Decl(objectSpread.ts, 82, 13))
+>t : Symbol(t, Decl(objectSpread.ts, 82, 17))
+>T : Symbol(T, Decl(objectSpread.ts, 82, 11))
+>u : Symbol(u, Decl(objectSpread.ts, 82, 22))
+>U : Symbol(U, Decl(objectSpread.ts, 82, 13))
+>T : Symbol(T, Decl(objectSpread.ts, 82, 11))
+>U : Symbol(U, Decl(objectSpread.ts, 82, 13))
+>id : Symbol(id, Decl(objectSpread.ts, 82, 43))
 
     return { ...t, ...u, id: 'id' };
->id : Symbol(id, Decl(objectSpread.ts, 85, 24))
+>id : Symbol(id, Decl(objectSpread.ts, 83, 24))
 }
 let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
->exclusive : Symbol(exclusive, Decl(objectSpread.ts, 87, 3))
->id : Symbol(id, Decl(objectSpread.ts, 87, 16))
->a : Symbol(a, Decl(objectSpread.ts, 87, 28))
->b : Symbol(b, Decl(objectSpread.ts, 87, 39))
->c : Symbol(c, Decl(objectSpread.ts, 87, 50))
->d : Symbol(d, Decl(objectSpread.ts, 87, 61))
+>exclusive : Symbol(exclusive, Decl(objectSpread.ts, 85, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 85, 16))
+>a : Symbol(a, Decl(objectSpread.ts, 85, 28))
+>b : Symbol(b, Decl(objectSpread.ts, 85, 39))
+>c : Symbol(c, Decl(objectSpread.ts, 85, 50))
+>d : Symbol(d, Decl(objectSpread.ts, 85, 61))
 
     f({ a: 1, b: 'yes' }, { c: 'no', d: false })
->f : Symbol(f, Decl(objectSpread.ts, 81, 55))
->a : Symbol(a, Decl(objectSpread.ts, 88, 7))
->b : Symbol(b, Decl(objectSpread.ts, 88, 13))
->c : Symbol(c, Decl(objectSpread.ts, 88, 27))
->d : Symbol(d, Decl(objectSpread.ts, 88, 36))
+>f : Symbol(f, Decl(objectSpread.ts, 79, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 86, 7))
+>b : Symbol(b, Decl(objectSpread.ts, 86, 13))
+>c : Symbol(c, Decl(objectSpread.ts, 86, 27))
+>d : Symbol(d, Decl(objectSpread.ts, 86, 36))
 
 let overlap: { id: string, a: number, b: string } =
->overlap : Symbol(overlap, Decl(objectSpread.ts, 89, 3))
->id : Symbol(id, Decl(objectSpread.ts, 89, 14))
->a : Symbol(a, Decl(objectSpread.ts, 89, 26))
->b : Symbol(b, Decl(objectSpread.ts, 89, 37))
+>overlap : Symbol(overlap, Decl(objectSpread.ts, 87, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 87, 14))
+>a : Symbol(a, Decl(objectSpread.ts, 87, 26))
+>b : Symbol(b, Decl(objectSpread.ts, 87, 37))
 
     f({ a: 1 }, { a: 2, b: 'extra' })
->f : Symbol(f, Decl(objectSpread.ts, 81, 55))
->a : Symbol(a, Decl(objectSpread.ts, 90, 7))
->a : Symbol(a, Decl(objectSpread.ts, 90, 17))
->b : Symbol(b, Decl(objectSpread.ts, 90, 23))
+>f : Symbol(f, Decl(objectSpread.ts, 79, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 88, 7))
+>a : Symbol(a, Decl(objectSpread.ts, 88, 17))
+>b : Symbol(b, Decl(objectSpread.ts, 88, 23))
 
 let overlapConflict: { id:string, a: string } =
->overlapConflict : Symbol(overlapConflict, Decl(objectSpread.ts, 91, 3))
->id : Symbol(id, Decl(objectSpread.ts, 91, 22))
->a : Symbol(a, Decl(objectSpread.ts, 91, 33))
+>overlapConflict : Symbol(overlapConflict, Decl(objectSpread.ts, 89, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 89, 22))
+>a : Symbol(a, Decl(objectSpread.ts, 89, 33))
 
     f({ a: 1 }, { a: 'mismatch' })
->f : Symbol(f, Decl(objectSpread.ts, 81, 55))
->a : Symbol(a, Decl(objectSpread.ts, 92, 7))
->a : Symbol(a, Decl(objectSpread.ts, 92, 17))
+>f : Symbol(f, Decl(objectSpread.ts, 79, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 90, 7))
+>a : Symbol(a, Decl(objectSpread.ts, 90, 17))
 
 let overwriteId: { id: string, a: number, c: number, d: string } =
->overwriteId : Symbol(overwriteId, Decl(objectSpread.ts, 93, 3))
->id : Symbol(id, Decl(objectSpread.ts, 93, 18))
->a : Symbol(a, Decl(objectSpread.ts, 93, 30))
->c : Symbol(c, Decl(objectSpread.ts, 93, 41))
->d : Symbol(d, Decl(objectSpread.ts, 93, 52))
+>overwriteId : Symbol(overwriteId, Decl(objectSpread.ts, 91, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 91, 18))
+>a : Symbol(a, Decl(objectSpread.ts, 91, 30))
+>c : Symbol(c, Decl(objectSpread.ts, 91, 41))
+>d : Symbol(d, Decl(objectSpread.ts, 91, 52))
 
     f({ a: 1, id: true }, { c: 1, d: 'no' })
->f : Symbol(f, Decl(objectSpread.ts, 81, 55))
->a : Symbol(a, Decl(objectSpread.ts, 94, 7))
->id : Symbol(id, Decl(objectSpread.ts, 94, 13))
->c : Symbol(c, Decl(objectSpread.ts, 94, 27))
->d : Symbol(d, Decl(objectSpread.ts, 94, 33))
+>f : Symbol(f, Decl(objectSpread.ts, 79, 55))
+>a : Symbol(a, Decl(objectSpread.ts, 92, 7))
+>id : Symbol(id, Decl(objectSpread.ts, 92, 13))
+>c : Symbol(c, Decl(objectSpread.ts, 92, 27))
+>d : Symbol(d, Decl(objectSpread.ts, 92, 33))
 
 class D { m() { }; q = 2; }
->D : Symbol(D, Decl(objectSpread.ts, 94, 44))
->m : Symbol(D.m, Decl(objectSpread.ts, 96, 9))
->q : Symbol(D.q, Decl(objectSpread.ts, 96, 18))
+>D : Symbol(D, Decl(objectSpread.ts, 92, 44))
+>m : Symbol(D.m, Decl(objectSpread.ts, 94, 9))
+>q : Symbol(D.q, Decl(objectSpread.ts, 94, 18))
 
 let classesAreWrong: { id: string, ...C, ...D } =
->classesAreWrong : Symbol(classesAreWrong, Decl(objectSpread.ts, 97, 3))
->id : Symbol(id, Decl(objectSpread.ts, 97, 22))
->C : Symbol(C, Decl(objectSpread.ts, 44, 29))
->D : Symbol(D, Decl(objectSpread.ts, 94, 44))
+>classesAreWrong : Symbol(classesAreWrong, Decl(objectSpread.ts, 95, 3))
+>id : Symbol(id, Decl(objectSpread.ts, 95, 22))
+>C : Symbol(C, Decl(objectSpread.ts, 42, 29))
+>D : Symbol(D, Decl(objectSpread.ts, 92, 44))
 
     f(new C(), new D())
->f : Symbol(f, Decl(objectSpread.ts, 81, 55))
->C : Symbol(C, Decl(objectSpread.ts, 44, 29))
->D : Symbol(D, Decl(objectSpread.ts, 94, 44))
+>f : Symbol(f, Decl(objectSpread.ts, 79, 55))
+>C : Symbol(C, Decl(objectSpread.ts, 42, 29))
+>D : Symbol(D, Decl(objectSpread.ts, 92, 44))
 
diff --git a/tests/baselines/reference/objectSpread.types b/tests/baselines/reference/objectSpread.types
index b6fcb9150bf3a..78f4f7583d939 100644
--- a/tests/baselines/reference/objectSpread.types
+++ b/tests/baselines/reference/objectSpread.types
@@ -223,7 +223,7 @@ getter.a = 12;
 >a : number
 >12 : 12
 
-// null, undefined, functions and primitives besides string result in { }
+// null, undefined, functions and primitives result in { }
 let spreadNull = { ...null };
 >spreadNull : {}
 >{ ...null } : {}
@@ -249,10 +249,9 @@ let spreadFunc = { ...(function () { }) };
 >(function () { }) : () => void
 >function () { } : () => void
 
-// strings get a numeric indexer: [n: number]: string
 let spreadStr = { ...'foo' };
->spreadStr : { [x: number]: string; }
->{ ...'foo' } : { [x: number]: string; }
+>spreadStr : {}
+>{ ...'foo' } : {}
 
 // methods are not enumerable
 class C { p = 1; m() { } }
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.errors.txt b/tests/baselines/reference/objectSpreadIndexSignature.errors.txt
new file mode 100644
index 0000000000000..3909c46695291
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadIndexSignature.errors.txt
@@ -0,0 +1,35 @@
+tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts(6,39): error TS2698: Type literals with spreads cannot contain an index signature.
+tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts(24,20): error TS2698: Type literals with spreads cannot contain an index signature.
+
+
+==== tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts (2 errors) ====
+    class C {
+        a: number;
+        c: boolean;
+    }
+    // index signatures are not allowed in object literals with spread types
+    let c: { ...C, b: string, c?: string, [n: number]: string };
+                                          ~~~~~~~~~~~~~~~~~~~
+!!! error TS2698: Type literals with spreads cannot contain an index signature.
+    let n: number = c.a;
+    let s: string = c[12];
+    interface Indexed {
+        [n: string]: number;
+        a: number;
+    }
+    let i: { ...Indexed, b: number };
+    n = i[101];
+    n = i.b;
+    interface Indexed2 {
+        [n: string]: boolean;
+        c: boolean;
+    }
+    let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
+    let nb: number | boolean = ii[1001];
+    
+    function f<T>(t: T) {
+        let i: { ...T, [n: number]: string };
+                       ~~~~~~~~~~~~~~~~~~~
+!!! error TS2698: Type literals with spreads cannot contain an index signature.
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.js b/tests/baselines/reference/objectSpreadIndexSignature.js
index 709cd9446d8da..ab18c0f24a942 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.js
+++ b/tests/baselines/reference/objectSpreadIndexSignature.js
@@ -3,6 +3,7 @@ class C {
     a: number;
     c: boolean;
 }
+// index signatures are not allowed in object literals with spread types
 let c: { ...C, b: string, c?: string, [n: number]: string };
 let n: number = c.a;
 let s: string = c[12];
@@ -31,6 +32,7 @@ var C = (function () {
     }
     return C;
 }());
+// index signatures are not allowed in object literals with spread types
 var c;
 var n = c.a;
 var s = c[12];
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.symbols b/tests/baselines/reference/objectSpreadIndexSignature.symbols
deleted file mode 100644
index e76ad3e1b1362..0000000000000
--- a/tests/baselines/reference/objectSpreadIndexSignature.symbols
+++ /dev/null
@@ -1,83 +0,0 @@
-=== tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts ===
-class C {
->C : Symbol(C, Decl(objectSpreadIndexSignature.ts, 0, 0))
-
-    a: number;
->a : Symbol(C.a, Decl(objectSpreadIndexSignature.ts, 0, 9))
-
-    c: boolean;
->c : Symbol(C.c, Decl(objectSpreadIndexSignature.ts, 1, 14))
-}
-let c: { ...C, b: string, c?: string, [n: number]: string };
->c : Symbol(c, Decl(objectSpreadIndexSignature.ts, 4, 3))
->C : Symbol(C, Decl(objectSpreadIndexSignature.ts, 0, 0))
->b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 4, 14))
->c : Symbol(c, Decl(objectSpreadIndexSignature.ts, 4, 25))
->n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 4, 39))
-
-let n: number = c.a;
->n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 5, 3))
->c.a : Symbol(C.a, Decl(objectSpreadIndexSignature.ts, 0, 9))
->c : Symbol(c, Decl(objectSpreadIndexSignature.ts, 4, 3))
->a : Symbol(C.a, Decl(objectSpreadIndexSignature.ts, 0, 9))
-
-let s: string = c[12];
->s : Symbol(s, Decl(objectSpreadIndexSignature.ts, 6, 3))
->c : Symbol(c, Decl(objectSpreadIndexSignature.ts, 4, 3))
-
-interface Indexed {
->Indexed : Symbol(Indexed, Decl(objectSpreadIndexSignature.ts, 6, 22))
-
-    [n: string]: number;
->n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 8, 5))
-
-    a: number;
->a : Symbol(Indexed.a, Decl(objectSpreadIndexSignature.ts, 8, 24))
-}
-let i: { ...Indexed, b: number };
->i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 11, 3))
->Indexed : Symbol(Indexed, Decl(objectSpreadIndexSignature.ts, 6, 22))
->b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 11, 20))
-
-n = i[101];
->n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 5, 3))
->i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 11, 3))
-
-n = i.b;
->n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 5, 3))
->i.b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 11, 20))
->i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 11, 3))
->b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 11, 20))
-
-interface Indexed2 {
->Indexed2 : Symbol(Indexed2, Decl(objectSpreadIndexSignature.ts, 13, 8))
-
-    [n: string]: boolean;
->n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 15, 5))
-
-    c: boolean;
->c : Symbol(Indexed2.c, Decl(objectSpreadIndexSignature.ts, 15, 25))
-}
-let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
->ii : Symbol(ii, Decl(objectSpreadIndexSignature.ts, 18, 3))
->Indexed : Symbol(Indexed, Decl(objectSpreadIndexSignature.ts, 6, 22))
->Indexed2 : Symbol(Indexed2, Decl(objectSpreadIndexSignature.ts, 13, 8))
->b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 18, 34))
->d : Symbol(d, Decl(objectSpreadIndexSignature.ts, 18, 46))
-
-let nb: number | boolean = ii[1001];
->nb : Symbol(nb, Decl(objectSpreadIndexSignature.ts, 19, 3))
->ii : Symbol(ii, Decl(objectSpreadIndexSignature.ts, 18, 3))
-
-function f<T>(t: T) {
->f : Symbol(f, Decl(objectSpreadIndexSignature.ts, 19, 36))
->T : Symbol(T, Decl(objectSpreadIndexSignature.ts, 21, 11))
->t : Symbol(t, Decl(objectSpreadIndexSignature.ts, 21, 14))
->T : Symbol(T, Decl(objectSpreadIndexSignature.ts, 21, 11))
-
-    let i: { ...T, [n: number]: string };
->i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 22, 7))
->T : Symbol(T, Decl(objectSpreadIndexSignature.ts, 21, 11))
->n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 22, 20))
-}
-
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.types b/tests/baselines/reference/objectSpreadIndexSignature.types
deleted file mode 100644
index f646361765d4b..0000000000000
--- a/tests/baselines/reference/objectSpreadIndexSignature.types
+++ /dev/null
@@ -1,91 +0,0 @@
-=== tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts ===
-class C {
->C : C
-
-    a: number;
->a : number
-
-    c: boolean;
->c : boolean
-}
-let c: { ...C, b: string, c?: string, [n: number]: string };
->c : { [x: number]: string; b: string; c: string | boolean; a: number; }
->C : C
->b : string
->c : string
->n : number
-
-let n: number = c.a;
->n : number
->c.a : number
->c : { [x: number]: string; b: string; c: string | boolean; a: number; }
->a : number
-
-let s: string = c[12];
->s : string
->c[12] : string
->c : { [x: number]: string; b: string; c: string | boolean; a: number; }
->12 : 12
-
-interface Indexed {
->Indexed : Indexed
-
-    [n: string]: number;
->n : string
-
-    a: number;
->a : number
-}
-let i: { ...Indexed, b: number };
->i : { [n: string]: number; b: number; a: number; }
->Indexed : Indexed
->b : number
-
-n = i[101];
->n = i[101] : number
->n : number
->i[101] : number
->i : { [n: string]: number; b: number; a: number; }
->101 : 101
-
-n = i.b;
->n = i.b : number
->n : number
->i.b : number
->i : { [n: string]: number; b: number; a: number; }
->b : number
-
-interface Indexed2 {
->Indexed2 : Indexed2
-
-    [n: string]: boolean;
->n : string
-
-    c: boolean;
->c : boolean
-}
-let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
->ii : { [x: string]: number | boolean; b: boolean; d: number; c: boolean; a: number; }
->Indexed : Indexed
->Indexed2 : Indexed2
->b : boolean
->d : number
-
-let nb: number | boolean = ii[1001];
->nb : number | boolean
->ii[1001] : number | boolean
->ii : { [x: string]: number | boolean; b: boolean; d: number; c: boolean; a: number; }
->1001 : 1001
-
-function f<T>(t: T) {
->f : <T>(t: T) => void
->T : T
->t : T
->T : T
-
-    let i: { ...T, [n: number]: string };
->i : { ...T; [n: number]: string; }
->T : T
->n : number
-}
-
diff --git a/tests/baselines/reference/objectSpreadIntersection.types b/tests/baselines/reference/objectSpreadIntersection.types
index 13c1384698f08..e6a7b7c19ee7f 100644
--- a/tests/baselines/reference/objectSpreadIntersection.types
+++ b/tests/baselines/reference/objectSpreadIntersection.types
@@ -187,21 +187,21 @@ function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
 >V : V
 
     let result = { ...tu, ...uv, id: 'qux' };
->result : { ...T & U; ...T & U; ...U; id: string; } | { ...T & U; ...T & U; ...V; id: string; }
->{ ...tu, ...uv, id: 'qux' } : { ...T & U; ...T & U; ...U; id: string; } | { ...T & U; ...T & U; ...V; id: string; }
+>result : { ...T & U; ...U; id: string; } | { ...T & U; ...V; id: string; }
+>{ ...tu, ...uv, id: 'qux' } : { ...T & U; ...U; id: string; } | { ...T & U; ...V; id: string; }
 >tu : any
 >uv : any
 >id : string
 >'qux' : "qux"
 
     let assignable: { ...(T & U), ...(U | V), id: string } = result;
->assignable : { ...T & U; ...T & U; ...U; id: string; } | { ...T & U; ...T & U; ...V; id: string; }
+>assignable : { ...T & U; ...U; id: string; } | { ...T & U; ...V; id: string; }
 >T : T
 >U : U
 >U : U
 >V : V
 >id : string
->result : { ...T & U; ...T & U; ...U; id: string; } | { ...T & U; ...T & U; ...V; id: string; }
+>result : { ...T & U; ...U; id: string; } | { ...T & U; ...V; id: string; }
 }
 
 
diff --git a/tests/baselines/reference/objectSpreadNegative.errors.txt b/tests/baselines/reference/objectSpreadNegative.errors.txt
index 64928782280ae..16c257b104419 100644
--- a/tests/baselines/reference/objectSpreadNegative.errors.txt
+++ b/tests/baselines/reference/objectSpreadNegative.errors.txt
@@ -11,8 +11,8 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(30,12): error TS233
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(32,17): error TS2339: Property 'undefined' does not exist on type '{}'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(36,11): error TS2339: Property 'toFixed' does not exist on type '{}'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(38,11): error TS2339: Property 'toFixed' does not exist on type '{}'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(40,11): error TS2339: Property 'length' does not exist on type '{ [x: number]: string; }'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(41,11): error TS2339: Property 'charAt' does not exist on type '{ [x: number]: string; }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(40,11): error TS2339: Property 'length' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(41,11): error TS2339: Property 'charAt' does not exist on type '{}'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(45,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{}' has no compatible call signatures.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(49,12): error TS2339: Property 'b' does not exist on type '{}'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(55,9): error TS2339: Property 'm' does not exist on type '{ p: number; }'.
@@ -87,10 +87,10 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(66,12): error TS232
     let spreadStr = { ...'foo' };
     spreadStr.length; // error, no 'length'
               ~~~~~~
-!!! error TS2339: Property 'length' does not exist on type '{ [x: number]: string; }'.
+!!! error TS2339: Property 'length' does not exist on type '{}'.
     spreadStr.charAt(1); // error, no methods either
               ~~~~~~
-!!! error TS2339: Property 'charAt' does not exist on type '{ [x: number]: string; }'.
+!!! error TS2339: Property 'charAt' does not exist on type '{}'.
     let spreadBool = { ...true };
     spreadBool.valueOf(); // error, what were you thinking?
     let spreadFunc = { ...function () { } }
diff --git a/tests/baselines/reference/objectSpreadUnion.types b/tests/baselines/reference/objectSpreadUnion.types
index 5d8cdbae24a70..20633295acba3 100644
--- a/tests/baselines/reference/objectSpreadUnion.types
+++ b/tests/baselines/reference/objectSpreadUnion.types
@@ -96,8 +96,8 @@ function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
 >V : V
 
     let result = { ...tu, ...uv, id: 'bar' };
->result : { ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; }
->{ ...tu, ...uv, id: 'bar' } : { ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; }
+>result : { ...U; id: string; } | { ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; ...V; id: string; }
+>{ ...tu, ...uv, id: 'bar' } : { ...U; id: string; } | { ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; ...V; id: string; }
 >tu : any
 >uv : any
 >id : string
@@ -118,13 +118,13 @@ function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
 >id : string
 
     let assignable: { ...(T | U), ...(U | V), id: string } = result;
->assignable : { ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; }
+>assignable : { ...U; id: string; } | { ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; ...V; id: string; }
 >T : T
 >U : U
 >U : U
 >V : V
 >id : string
->result : { ...U; id: string; } | { ...T; ...U; id: string; } | { ...U; ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; ...T; ...V; id: string; } | { ...U; ...V; id: string; } | { ...T; ...U; ...V; id: string; }
+>result : { ...U; id: string; } | { ...T; ...U; id: string; } | { ...T; ...V; id: string; } | { ...U; ...V; id: string; }
 }
 
 
diff --git a/tests/cases/conformance/types/spread/objectSpread.ts b/tests/cases/conformance/types/spread/objectSpread.ts
index e35a84956c00a..daadb1e3270e5 100644
--- a/tests/cases/conformance/types/spread/objectSpread.ts
+++ b/tests/cases/conformance/types/spread/objectSpread.ts
@@ -35,14 +35,12 @@ let getter: { a: number, c: number } =
     { ...op, c: 7 }
 getter.a = 12;
 
-// null, undefined, functions and primitives besides string result in { }
+// null, undefined, functions and primitives result in { }
 let spreadNull = { ...null };
 let spreadUndefind = { ...undefined };
 let spreadNum = { ...12 };
 let spreadBool = { ...false };
 let spreadFunc = { ...(function () { }) };
-
-// strings get a numeric indexer: [n: number]: string
 let spreadStr = { ...'foo' };
 
 // methods are not enumerable
diff --git a/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts b/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
index daf8e4e63c573..8c9194d2d4cdc 100644
--- a/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
@@ -2,6 +2,7 @@ class C {
     a: number;
     c: boolean;
 }
+// index signatures are not allowed in object literals with spread types
 let c: { ...C, b: string, c?: string, [n: number]: string };
 let n: number = c.a;
 let s: string = c[12];

From 510ab1c42ff4652f7209efa69846b6c8fc75fb42 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 21 Oct 2016 16:33:28 -0700
Subject: [PATCH 072/224] Move n-ary spread handling into separate function.

To be moved to callers in the next step.
---
 src/compiler/checker.ts              | 63 ++++++++++++++++++----------
 src/compiler/diagnosticMessages.json |  4 ++
 2 files changed, 46 insertions(+), 21 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 9df086f1bb70f..abc70d49a435b 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5803,7 +5803,8 @@ namespace ts {
             return getSpreadType(spreads, node.symbol, aliasSymbol, aliasTypeArguments);
         }
 
-        function getSpreadType(types: Type[], symbol: Symbol, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
+        function getSpreadType(types: Type[], symbol: Symbol, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]) {
+            // TODO: Move this function's body into callers, except for caching, and leave that back in getSpreadType proper
             if (types.length === 0) {
                 return emptyObjectType;
             }
@@ -5811,9 +5812,18 @@ namespace ts {
             if (id in spreadTypes) {
                 return spreadTypes[id];
             }
-            let right = types.pop();
-            if (right.flags & TypeFlags.StringLike) {
-                right = createAnonymousType(symbol, emptySymbols, emptyArray, emptyArray, undefined, createIndexInfo(stringType, /*isReadonly*/ false));
+            let spread: Type = emptyObjectType;
+            for (const left of types) {
+                spread = getSpreadTypeWorker(spread, left, symbol, aliasSymbol, aliasTypeArguments);
+            }
+            return spread;
+        }
+
+        function getSpreadTypeWorker(left: Type, right: Type, symbol: Symbol, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
+            // TODO: Reorder everything now that it's order independent, to be easier to read
+            const id = getTypeListId([left, right]);
+            if (id in spreadTypes) {
+                return spreadTypes[id];
             }
             if (right.flags & TypeFlags.Any) {
                 return anyType;
@@ -5822,23 +5832,21 @@ namespace ts {
                 // spread is right associative and associativity applies, so transform
                 // (T ... U) ... V to T ... (U ... V)
                 const rspread = right as SpreadType;
-                if (rspread.left !== emptyObjectType) {
-                    types.push(rspread.left);
+                if (rspread.left === emptyObjectType) {
+                    return getSpreadTypeWorker(left, rspread.right, symbol, aliasSymbol, aliasTypeArguments);
                 }
-                types.push(rspread.right);
-                return getSpreadType(types, symbol, aliasSymbol, aliasTypeArguments);
+                return getSpreadTypeWorker(getSpreadTypeWorker(left, rspread.left, symbol, aliasSymbol, aliasTypeArguments),
+                                           rspread.right, symbol, aliasSymbol, aliasTypeArguments);
             }
             if (right.flags & TypeFlags.Intersection) {
                 right = resolveObjectIntersection(right as IntersectionType);
             }
             if (right.flags & TypeFlags.Union) {
                 const spreads = map((right as UnionType).types,
-                                    t => getSpreadType(types.slice().concat([t]), symbol, aliasSymbol, aliasTypeArguments));
+                                    t => getSpreadTypeWorker(left, t, symbol, aliasSymbol, aliasTypeArguments));
                 return getUnionType(spreads, /*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
             }
-            const atBeginning = types.length === 0;
-            let left = getSpreadType(types, symbol, aliasSymbol, aliasTypeArguments);
-            if (right.flags & (TypeFlags.Primitive & ~TypeFlags.StringLike) || left.flags & TypeFlags.Any) {
+            if (right.flags & TypeFlags.Primitive || left.flags & TypeFlags.Any) {
                 return left;
             }
             if (right.flags & TypeFlags.TypeParameter &&
@@ -5861,19 +5869,21 @@ namespace ts {
             }
             if (left.flags & TypeFlags.Union) {
                 const spreads = map((left as UnionType).types,
-                                  t => getSpreadType(types.slice().concat([t, right]), symbol, aliasSymbol, aliasTypeArguments));
+                                    t => getSpreadTypeWorker(t, right, symbol, aliasSymbol, aliasTypeArguments));
                 return getUnionType(spreads, /*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
             }
             if (right.flags & TypeFlags.ObjectType && left.flags & TypeFlags.ObjectType) {
                 const members = createMap<Symbol>();
                 const skippedPrivateMembers = createMap<boolean>();
-                let stringIndexInfo = unionIndexInfos(getIndexInfoOfType(left, IndexKind.String), getIndexInfoOfType(right, IndexKind.String));
-                let numberIndexInfo = unionIndexInfos(getIndexInfoOfType(left, IndexKind.Number), getIndexInfoOfType(right, IndexKind.Number));
-                if (atBeginning) {
-                    // only get index info from the entire type once per spread type
-                    stringIndexInfo = unionIndexInfos(stringIndexInfo, getIndexInfoOfSymbol(symbol, IndexKind.String));
-                    numberIndexInfo = unionIndexInfos(numberIndexInfo, getIndexInfoOfSymbol(symbol, IndexKind.Number));
-                }
+
+                // TODO: This is pretty ugly
+                const leftString = getIndexInfoOfType(left, IndexKind.String);
+                const rightString = getIndexInfoOfType(right, IndexKind.String);
+                const leftNumber = getIndexInfoOfType(left, IndexKind.Number);
+                const rightNumber = getIndexInfoOfType(right, IndexKind.Number);
+                const stringIndexInfo = leftString && rightString && unionIndexInfos(leftString, rightString);
+                const numberIndexInfo = leftNumber && rightNumber && unionIndexInfos(leftNumber, rightNumber);
+
                 const isFromSpread = right.symbol !== symbol;
                 for (const rightProp of getPropertiesOfType(right)) {
                     if (getDeclarationModifierFlagsFromSymbol(rightProp) & (ModifierFlags.Private | ModifierFlags.Protected)) {
@@ -5924,7 +5934,7 @@ namespace ts {
         }
 
         function resolveObjectIntersection(intersection: IntersectionType): IntersectionType | ResolvedType {
-            if (find(intersection.types, t => !(t.flags & TypeFlags.ObjectType) || couldContainTypeParameters(t))) {
+            if (find(intersection.types, t => !(t.flags & TypeFlags.ObjectType))) {
                 return intersection;
             }
             const properties = getPropertiesOfType(intersection);
@@ -15267,6 +15277,17 @@ namespace ts {
                     checkTypeForDuplicateIndexSignatures(node);
                     checkObjectTypeForDuplicateDeclarations(node);
                 }
+                if (type.flags & (TypeFlags.ObjectType | TypeFlags.Spread) &&
+                    find(node.members, p => p.kind === SyntaxKind.SpreadTypeElement)) {
+                    const declaredNumberIndexer = getIndexDeclarationOfSymbol(type.symbol, IndexKind.Number);
+                    const declaredStringIndexer = getIndexDeclarationOfSymbol(type.symbol, IndexKind.String);
+                    if (declaredStringIndexer) {
+                        error(declaredStringIndexer, Diagnostics.Type_literals_with_spreads_cannot_contain_an_index_signature);
+                    }
+                    if (declaredNumberIndexer) {
+                        error(declaredNumberIndexer, Diagnostics.Type_literals_with_spreads_cannot_contain_an_index_signature);
+                    }
+                }
             }
         }
 
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index bfc6dabfb9d1d..424d6f59ca0a0 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1971,6 +1971,10 @@
         "category": "Error",
         "code": 2697
     },
+    "Type literals with spreads cannot contain an index signature.": {
+        "category": "Error",
+        "code": 2698
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

From 485e2490e77c2aad766375e3981360bbe4fc9c4e Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Sat, 22 Oct 2016 09:07:48 -0700
Subject: [PATCH 073/224] Move multiple-spread handling out of getSpreadType

---
 src/compiler/checker.ts | 50 +++++++++++++++++------------------------
 1 file changed, 20 insertions(+), 30 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index abc70d49a435b..a610dcf2f36e9 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5753,19 +5753,19 @@ namespace ts {
         }
 
         function getTypeFromSpreadTypeLiteral(node: Node, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
+            let spread: Type = emptyObjectType;
             let members: Map<Symbol>;
             let stringIndexInfo: IndexInfo;
             let numberIndexInfo: IndexInfo;
-            const spreads: Type[] = [];
             for (const member of (node as TypeLiteralNode).members) {
                 if (member.kind === SyntaxKind.SpreadTypeElement) {
                     if (members) {
-                        spreads.push(createAnonymousType(node.symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo));
+                        spread = getSpreadTypeWorker(spread, createAnonymousType(node.symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo), node.symbol, aliasSymbol, aliasTypeArguments);
                         members = undefined;
                         stringIndexInfo = undefined;
                         numberIndexInfo = undefined;
                     }
-                    spreads.push(getTypeFromTypeNode((member as SpreadTypeElement).type));
+                    spread = getSpreadTypeWorker(spread, getTypeFromTypeNode((member as SpreadTypeElement).type), node.symbol, aliasSymbol, aliasTypeArguments);
                 }
                 else if (member.kind === SyntaxKind.IndexSignature) {
                     const index = member as IndexSignatureDeclaration;
@@ -5798,23 +5798,7 @@ namespace ts {
                 }
             }
             if (members || stringIndexInfo || numberIndexInfo) {
-                spreads.push(createAnonymousType(node.symbol, members || emptySymbols, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo));
-            }
-            return getSpreadType(spreads, node.symbol, aliasSymbol, aliasTypeArguments);
-        }
-
-        function getSpreadType(types: Type[], symbol: Symbol, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]) {
-            // TODO: Move this function's body into callers, except for caching, and leave that back in getSpreadType proper
-            if (types.length === 0) {
-                return emptyObjectType;
-            }
-            const id = getTypeListId(types);
-            if (id in spreadTypes) {
-                return spreadTypes[id];
-            }
-            let spread: Type = emptyObjectType;
-            for (const left of types) {
-                spread = getSpreadTypeWorker(spread, left, symbol, aliasSymbol, aliasTypeArguments);
+                spread = getSpreadTypeWorker(spread, createAnonymousType(node.symbol, members || emptySymbols, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo), node.symbol, aliasSymbol, aliasTypeArguments);
             }
             return spread;
         }
@@ -5861,8 +5845,8 @@ namespace ts {
                 left.flags & TypeFlags.Spread &&
                 (left as SpreadType).right.flags & TypeFlags.ObjectType) {
                 // simplify two adjacent object types: T ... { x } ... { y } becomes T ... { x, y }
-                const simplified = getSpreadType([right, (left as SpreadType).right], symbol, aliasSymbol, aliasTypeArguments);
-                return getSpreadType([(left as SpreadType).left, simplified], symbol, aliasSymbol, aliasTypeArguments);
+                const simplified = getSpreadTypeWorker(right, (left as SpreadType).right, symbol, aliasSymbol, aliasTypeArguments);
+                return getSpreadTypeWorker((left as SpreadType).left, simplified, symbol, aliasSymbol, aliasTypeArguments);
             }
             if (left.flags & TypeFlags.Intersection) {
                 left = resolveObjectIntersection(left as IntersectionType);
@@ -6355,7 +6339,7 @@ namespace ts {
                 }
                 if (type.flags & TypeFlags.Spread) {
                     const spread = type as SpreadType;
-                    return getSpreadType([instantiateType(spread.left, mapper), instantiateType(spread.right, mapper)], type.symbol, type.aliasSymbol, mapper.targetTypes);
+                    return getSpreadTypeWorker(instantiateType(spread.left, mapper), instantiateType(spread.right, mapper), type.symbol, type.aliasSymbol, mapper.targetTypes);
                 }
             }
             return type;
@@ -10881,7 +10865,9 @@ namespace ts {
 
             let propertiesTable = createMap<Symbol>();
             let propertiesArray: Symbol[] = [];
-            const spreads: Type[] = [];
+            let spread: Type = emptyObjectType;
+            let propagatedFlags: TypeFlags = 0;
+
             const contextualType = getApparentTypeOfContextualType(node);
             const contextualTypeHasPattern = contextualType && contextualType.pattern &&
                 (contextualType.pattern.kind === SyntaxKind.ObjectBindingPattern || contextualType.pattern.kind === SyntaxKind.ObjectLiteralExpression);
@@ -10947,13 +10933,15 @@ namespace ts {
                 }
                 else if (memberDecl.kind === SyntaxKind.SpreadElementExpression) {
                     if (propertiesArray.length > 0) {
-                        spreads.push(createObjectLiteralType());
+                        spread = getSpreadTypeWorker(spread, createObjectLiteralType(), node.symbol);
                         propertiesArray = [];
                         propertiesTable = createMap<Symbol>();
                         hasComputedStringProperty = false;
                         hasComputedNumberProperty = false;
+                        typeFlags = 0;
                     }
-                    spreads.push(checkExpression((memberDecl as SpreadElementExpression).expression));
+                    const type = checkExpression((memberDecl as SpreadElementExpression).expression);
+                    spread = getSpreadTypeWorker(spread, type, node.symbol);
                     continue;
                 }
                 else {
@@ -10995,12 +10983,11 @@ namespace ts {
                 }
             }
 
-            if (spreads.length > 0) {
+            if (spread !== emptyObjectType) {
                 if (propertiesArray.length > 0) {
-                    spreads.push(createObjectLiteralType());
+                    spread = getSpreadTypeWorker(spread, createObjectLiteralType(), node.symbol);
                 }
-                const propagatedFlags = getPropagatingFlagsOfTypes(spreads, /*excludeKinds*/ TypeFlags.Nullable);
-                const spread = getSpreadType(spreads, node.symbol, undefined, undefined);
+                // TODO: REname getSpreadTypeWorker back to getSpreadType
                 spread.flags |= propagatedFlags;
                 return spread;
             }
@@ -11019,6 +11006,9 @@ namespace ts {
                 if (inDestructuringPattern) {
                     result.pattern = node;
                 }
+                if (!(result.flags & TypeFlags.Nullable)) {
+                    propagatedFlags |= (result.flags & TypeFlags.PropagatingFlags);
+                }
                 return result;
             }
        }

From 16dfdc49dc25d11a51a60225b5aee63ef890b8ca Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Sat, 22 Oct 2016 10:08:58 -0700
Subject: [PATCH 074/224] Clean up and reorder getSpreadType body

---
 src/compiler/checker.ts | 93 +++++++++++++++++++++--------------------
 1 file changed, 48 insertions(+), 45 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index a610dcf2f36e9..2560b12597d64 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4358,8 +4358,8 @@ namespace ts {
                 getIntersectionType([info1.type, info2.type]), info1.isReadonly && info2.isReadonly);
         }
 
-        function unionIndexInfos(info1: IndexInfo, info2: IndexInfo): IndexInfo {
-            return !info1 ? info2 : !info2 ? info1 : createIndexInfo(
+        function unionSpreadIndexInfos(info1: IndexInfo, info2: IndexInfo): IndexInfo {
+            return info1 && info2 && createIndexInfo(
                 getUnionType([info1.type, info2.type]), info1.isReadonly || info2.isReadonly);
         }
 
@@ -5760,12 +5760,14 @@ namespace ts {
             for (const member of (node as TypeLiteralNode).members) {
                 if (member.kind === SyntaxKind.SpreadTypeElement) {
                     if (members) {
-                        spread = getSpreadTypeWorker(spread, createAnonymousType(node.symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo), node.symbol, aliasSymbol, aliasTypeArguments);
+                        const type = createAnonymousType(node.symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
+                        spread = getSpreadType(spread, type, node.symbol, aliasSymbol, aliasTypeArguments);
                         members = undefined;
                         stringIndexInfo = undefined;
                         numberIndexInfo = undefined;
                     }
-                    spread = getSpreadTypeWorker(spread, getTypeFromTypeNode((member as SpreadTypeElement).type), node.symbol, aliasSymbol, aliasTypeArguments);
+                    const type = getTypeFromTypeNode((member as SpreadTypeElement).type);
+                    spread = getSpreadType(spread, type, node.symbol, aliasSymbol, aliasTypeArguments);
                 }
                 else if (member.kind === SyntaxKind.IndexSignature) {
                     const index = member as IndexSignatureDeclaration;
@@ -5798,75 +5800,77 @@ namespace ts {
                 }
             }
             if (members || stringIndexInfo || numberIndexInfo) {
-                spread = getSpreadTypeWorker(spread, createAnonymousType(node.symbol, members || emptySymbols, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo), node.symbol, aliasSymbol, aliasTypeArguments);
+                const type = createAnonymousType(node.symbol, members || emptySymbols, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
+                spread = getSpreadType(spread, type, node.symbol, aliasSymbol, aliasTypeArguments);
             }
             return spread;
         }
 
-        function getSpreadTypeWorker(left: Type, right: Type, symbol: Symbol, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
+        function getSpreadType(left: Type, right: Type, symbol: Symbol, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
             // TODO: Reorder everything now that it's order independent, to be easier to read
             const id = getTypeListId([left, right]);
             if (id in spreadTypes) {
                 return spreadTypes[id];
             }
-            if (right.flags & TypeFlags.Any) {
+
+            // non-spreadable types
+            if (left.flags & TypeFlags.Any || right.flags & TypeFlags.Any) {
                 return anyType;
             }
-            if (right.flags & TypeFlags.Spread) {
-                // spread is right associative and associativity applies, so transform
-                // (T ... U) ... V to T ... (U ... V)
-                const rspread = right as SpreadType;
-                if (rspread.left === emptyObjectType) {
-                    return getSpreadTypeWorker(left, rspread.right, symbol, aliasSymbol, aliasTypeArguments);
-                }
-                return getSpreadTypeWorker(getSpreadTypeWorker(left, rspread.left, symbol, aliasSymbol, aliasTypeArguments),
-                                           rspread.right, symbol, aliasSymbol, aliasTypeArguments);
+            if (left.flags & TypeFlags.Intersection) {
+                left = resolveObjectIntersection(left as IntersectionType);
             }
             if (right.flags & TypeFlags.Intersection) {
                 right = resolveObjectIntersection(right as IntersectionType);
             }
+            if (left.flags & TypeFlags.Union) {
+                const spreads = map((left as UnionType).types,
+                                    t => getSpreadType(t, right, symbol, aliasSymbol, aliasTypeArguments));
+                return getUnionType(spreads, /*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
+            }
             if (right.flags & TypeFlags.Union) {
                 const spreads = map((right as UnionType).types,
-                                    t => getSpreadTypeWorker(left, t, symbol, aliasSymbol, aliasTypeArguments));
+                                    t => getSpreadType(left, t, symbol, aliasSymbol, aliasTypeArguments));
                 return getUnionType(spreads, /*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
             }
-            if (right.flags & TypeFlags.Primitive || left.flags & TypeFlags.Any) {
+            if (right.flags & TypeFlags.Primitive) {
                 return left;
             }
-            if (right.flags & TypeFlags.TypeParameter &&
-                left.flags & TypeFlags.Spread &&
+
+            // spread simplifications
+            if (left.flags & TypeFlags.Spread &&
+                right.flags & TypeFlags.TypeParameter &&
                 (left as SpreadType).right.flags & TypeFlags.TypeParameter &&
                 right.symbol === (left as SpreadType).right.symbol) {
                 // for types like T ... T, just return ... T
                 return left;
             }
-
-            if (right.flags & TypeFlags.ObjectType &&
-                left.flags & TypeFlags.Spread &&
+            if (left.flags & TypeFlags.Spread &&
+                right.flags & TypeFlags.ObjectType &&
                 (left as SpreadType).right.flags & TypeFlags.ObjectType) {
                 // simplify two adjacent object types: T ... { x } ... { y } becomes T ... { x, y }
-                const simplified = getSpreadTypeWorker(right, (left as SpreadType).right, symbol, aliasSymbol, aliasTypeArguments);
-                return getSpreadTypeWorker((left as SpreadType).left, simplified, symbol, aliasSymbol, aliasTypeArguments);
-            }
-            if (left.flags & TypeFlags.Intersection) {
-                left = resolveObjectIntersection(left as IntersectionType);
+                const simplified = getSpreadType(right, (left as SpreadType).right, symbol, aliasSymbol, aliasTypeArguments);
+                return getSpreadType((left as SpreadType).left, simplified, symbol, aliasSymbol, aliasTypeArguments);
             }
-            if (left.flags & TypeFlags.Union) {
-                const spreads = map((left as UnionType).types,
-                                    t => getSpreadTypeWorker(t, right, symbol, aliasSymbol, aliasTypeArguments));
-                return getUnionType(spreads, /*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
+            if (right.flags & TypeFlags.Spread) {
+                // spread is right associative and associativity applies, so transform
+                // (T ... U) ... V to T ... (U ... V)
+                const rspread = right as SpreadType;
+                if (rspread.left === emptyObjectType) {
+                    // U ... ({} ... T) => (U ... T)
+                    return getSpreadType(left, rspread.right, symbol, aliasSymbol, aliasTypeArguments);
+                }
+                return getSpreadType(getSpreadType(left, rspread.left, symbol, aliasSymbol, aliasTypeArguments),
+                                     rspread.right, symbol, aliasSymbol, aliasTypeArguments);
             }
+
+            // create an object type if left and right are both objects,
+            // otherwise create a spread type
             if (right.flags & TypeFlags.ObjectType && left.flags & TypeFlags.ObjectType) {
                 const members = createMap<Symbol>();
                 const skippedPrivateMembers = createMap<boolean>();
-
-                // TODO: This is pretty ugly
-                const leftString = getIndexInfoOfType(left, IndexKind.String);
-                const rightString = getIndexInfoOfType(right, IndexKind.String);
-                const leftNumber = getIndexInfoOfType(left, IndexKind.Number);
-                const rightNumber = getIndexInfoOfType(right, IndexKind.Number);
-                const stringIndexInfo = leftString && rightString && unionIndexInfos(leftString, rightString);
-                const numberIndexInfo = leftNumber && rightNumber && unionIndexInfos(leftNumber, rightNumber);
+                const stringIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.String), getIndexInfoOfType(right, IndexKind.String));
+                const numberIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.Number), getIndexInfoOfType(right, IndexKind.Number));
 
                 const isFromSpread = right.symbol !== symbol;
                 for (const rightProp of getPropertiesOfType(right)) {
@@ -6339,7 +6343,7 @@ namespace ts {
                 }
                 if (type.flags & TypeFlags.Spread) {
                     const spread = type as SpreadType;
-                    return getSpreadTypeWorker(instantiateType(spread.left, mapper), instantiateType(spread.right, mapper), type.symbol, type.aliasSymbol, mapper.targetTypes);
+                    return getSpreadType(instantiateType(spread.left, mapper), instantiateType(spread.right, mapper), type.symbol, type.aliasSymbol, mapper.targetTypes);
                 }
             }
             return type;
@@ -10933,7 +10937,7 @@ namespace ts {
                 }
                 else if (memberDecl.kind === SyntaxKind.SpreadElementExpression) {
                     if (propertiesArray.length > 0) {
-                        spread = getSpreadTypeWorker(spread, createObjectLiteralType(), node.symbol);
+                        spread = getSpreadType(spread, createObjectLiteralType(), node.symbol);
                         propertiesArray = [];
                         propertiesTable = createMap<Symbol>();
                         hasComputedStringProperty = false;
@@ -10941,7 +10945,7 @@ namespace ts {
                         typeFlags = 0;
                     }
                     const type = checkExpression((memberDecl as SpreadElementExpression).expression);
-                    spread = getSpreadTypeWorker(spread, type, node.symbol);
+                    spread = getSpreadType(spread, type, node.symbol);
                     continue;
                 }
                 else {
@@ -10985,9 +10989,8 @@ namespace ts {
 
             if (spread !== emptyObjectType) {
                 if (propertiesArray.length > 0) {
-                    spread = getSpreadTypeWorker(spread, createObjectLiteralType(), node.symbol);
+                    spread = getSpreadType(spread, createObjectLiteralType(), node.symbol);
                 }
-                // TODO: REname getSpreadTypeWorker back to getSpreadType
                 spread.flags |= propagatedFlags;
                 return spread;
             }

From 71576921913f9f4e5004f5395a7dcce37b17a989 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Mon, 24 Oct 2016 06:48:05 -0700
Subject: [PATCH 075/224] Respond to PR comments

---
 src/compiler/commandLineParser.ts | 6 ++----
 src/compiler/core.ts              | 8 ++++----
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 8ffae3b8680dc..6105ae32ba5fc 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -1295,12 +1295,10 @@ namespace ts {
                 flags: watchRecursivePattern.test(spec) ? WatchDirectoryFlags.Recursive : WatchDirectoryFlags.None
             };
         }
-        else if (isImplicitGlob(spec)) {
+        if (isImplicitGlob(spec)) {
             return { key: spec, flags: WatchDirectoryFlags.Recursive };
         }
-        else {
-            return undefined;
-        }
+        return undefined;
     }
 
     /**
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 0164d0f43339a..1eb0614a8a391 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -1515,7 +1515,9 @@ namespace ts {
             return undefined;
         }
 
-        return "^(" + pattern + (usage === "exclude" ? ")($|/)" : ")$");
+        // If excluding, match "foo/bar/baz...", but if including, only allow "foo".
+        const terminator = usage === "exclude" ? "($|/)" : "$";
+        return `^(${pattern})${terminator}`;
     }
 
     /**
@@ -1711,9 +1713,7 @@ namespace ts {
                 ? absolute
                 : removeTrailingDirectorySeparator(getDirectoryPath(absolute));
         }
-        else {
-            return absolute.substring(0, absolute.lastIndexOf(directorySeparator, wildcardOffset));
-        }
+        return absolute.substring(0, absolute.lastIndexOf(directorySeparator, wildcardOffset));
     }
 
     export function ensureScriptKind(fileName: string, scriptKind?: ScriptKind): ScriptKind {

From 66d4798145ae9b7af5633b64f228f149e10a4fee Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 24 Oct 2016 09:21:23 -0700
Subject: [PATCH 076/224] Error for call/construct signatures in spread type

1. Simplify the error reporting code to handle all kinds of signatures.
2. Remove index signature handling code when creating a spread type
since it's an error anyway.
---
 src/compiler/checker.ts              | 36 +++++++---------------------
 src/compiler/diagnosticMessages.json |  2 +-
 2 files changed, 10 insertions(+), 28 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 2560b12597d64..e19c779b35a84 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5769,24 +5769,10 @@ namespace ts {
                     const type = getTypeFromTypeNode((member as SpreadTypeElement).type);
                     spread = getSpreadType(spread, type, node.symbol, aliasSymbol, aliasTypeArguments);
                 }
-                else if (member.kind === SyntaxKind.IndexSignature) {
-                    const index = member as IndexSignatureDeclaration;
-                    if (index.parameters.length === 1) {
-                        const parameter = index.parameters[0];
-                        if (parameter && parameter.type) {
-                            const indexInfo = createIndexInfo(index.type ? getTypeFromTypeNode(index.type) : anyType,
-                                                              (getModifierFlags(index) & ModifierFlags.Readonly) !== 0, index);
-                            if (parameter.type.kind === SyntaxKind.StringKeyword) {
-                                stringIndexInfo = indexInfo;
-                            }
-                            else {
-                                numberIndexInfo = indexInfo;
-                            }
-                        }
-                    }
-                }
-                else if (member.kind !== SyntaxKind.CallSignature && member.kind !== SyntaxKind.ConstructSignature) {
-                    // note that spread types don't include call and construct signatures
+                else if (member.kind !== SyntaxKind.IndexSignature &&
+                         member.kind !== SyntaxKind.CallSignature &&
+                         member.kind !== SyntaxKind.ConstructSignature) {
+                    // it is an error for spread types to include index, call or construct signatures
                     const flags = SymbolFlags.Property | SymbolFlags.Transient | (member.questionToken ? SymbolFlags.Optional : 0);
                     const text = getTextOfPropertyName(member.name);
                     const symbol = <TransientSymbol>createSymbol(flags, text);
@@ -15270,15 +15256,11 @@ namespace ts {
                     checkTypeForDuplicateIndexSignatures(node);
                     checkObjectTypeForDuplicateDeclarations(node);
                 }
-                if (type.flags & (TypeFlags.ObjectType | TypeFlags.Spread) &&
-                    find(node.members, p => p.kind === SyntaxKind.SpreadTypeElement)) {
-                    const declaredNumberIndexer = getIndexDeclarationOfSymbol(type.symbol, IndexKind.Number);
-                    const declaredStringIndexer = getIndexDeclarationOfSymbol(type.symbol, IndexKind.String);
-                    if (declaredStringIndexer) {
-                        error(declaredStringIndexer, Diagnostics.Type_literals_with_spreads_cannot_contain_an_index_signature);
-                    }
-                    if (declaredNumberIndexer) {
-                        error(declaredNumberIndexer, Diagnostics.Type_literals_with_spreads_cannot_contain_an_index_signature);
+                if (find(node.members, p => p.kind === SyntaxKind.SpreadTypeElement)) {
+                    for (const signature of filter(node.members, p => p.kind === SyntaxKind.IndexSignature ||
+                                                                      p.kind === SyntaxKind.CallSignature ||
+                                                                      p.kind === SyntaxKind.ConstructSignature)) {
+                        error(signature, Diagnostics.Type_literals_with_spreads_cannot_contain_index_call_or_construct_signatures);
                     }
                 }
             }
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 424d6f59ca0a0..68206196dff18 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1971,7 +1971,7 @@
         "category": "Error",
         "code": 2697
     },
-    "Type literals with spreads cannot contain an index signature.": {
+    "Type literals with spreads cannot contain index, call or construct signatures.": {
         "category": "Error",
         "code": 2698
     },

From 24300932cfea12050748522f380bc53ee504f0b2 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 24 Oct 2016 09:22:40 -0700
Subject: [PATCH 077/224] Update baselines with new spread type index errors

---
 .../reference/objectSpreadIndexSignature.errors.txt       | 8 ++++----
 tests/baselines/reference/objectSpreadNegative.errors.txt | 8 +++++++-
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/tests/baselines/reference/objectSpreadIndexSignature.errors.txt b/tests/baselines/reference/objectSpreadIndexSignature.errors.txt
index 3909c46695291..fa4d4c28aecaf 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.errors.txt
+++ b/tests/baselines/reference/objectSpreadIndexSignature.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts(6,39): error TS2698: Type literals with spreads cannot contain an index signature.
-tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts(24,20): error TS2698: Type literals with spreads cannot contain an index signature.
+tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts(6,39): error TS2698: Type literals with spreads cannot contain index, call or construct signatures.
+tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts(24,20): error TS2698: Type literals with spreads cannot contain index, call or construct signatures.
 
 
 ==== tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts (2 errors) ====
@@ -10,7 +10,7 @@ tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts(24,20): error
     // index signatures are not allowed in object literals with spread types
     let c: { ...C, b: string, c?: string, [n: number]: string };
                                           ~~~~~~~~~~~~~~~~~~~
-!!! error TS2698: Type literals with spreads cannot contain an index signature.
+!!! error TS2698: Type literals with spreads cannot contain index, call or construct signatures.
     let n: number = c.a;
     let s: string = c[12];
     interface Indexed {
@@ -30,6 +30,6 @@ tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts(24,20): error
     function f<T>(t: T) {
         let i: { ...T, [n: number]: string };
                        ~~~~~~~~~~~~~~~~~~~
-!!! error TS2698: Type literals with spreads cannot contain an index signature.
+!!! error TS2698: Type literals with spreads cannot contain index, call or construct signatures.
     }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadNegative.errors.txt b/tests/baselines/reference/objectSpreadNegative.errors.txt
index 16c257b104419..90cd2405c24e0 100644
--- a/tests/baselines/reference/objectSpreadNegative.errors.txt
+++ b/tests/baselines/reference/objectSpreadNegative.errors.txt
@@ -16,13 +16,15 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(41,11): error TS233
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(45,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{}' has no compatible call signatures.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(49,12): error TS2339: Property 'b' does not exist on type '{}'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(55,9): error TS2339: Property 'm' does not exist on type '{ p: number; }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(57,48): error TS2698: Type literals with spreads cannot contain index, call or construct signatures.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(57,69): error TS2698: Type literals with spreads cannot contain index, call or construct signatures.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(58,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ x: number; }' has no compatible call signatures.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(59,1): error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(64,9): error TS2322: Type '{ ...T & V }' is not assignable to type '{ ...T & U }'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(66,12): error TS2322: Type '{ ...U }' is not assignable to type 'U'.
 
 
-==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (19 errors) ====
+==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (21 errors) ====
     let o = { a: 1, b: 'no' }
     
     /// private propagates
@@ -113,6 +115,10 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(66,12): error TS232
 !!! error TS2339: Property 'm' does not exist on type '{ p: number; }'.
     
     let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: number) };
+                                                   ~~~~~~~~~~~~~~~~~~~~
+!!! error TS2698: Type literals with spreads cannot contain index, call or construct signatures.
+                                                                        ~~~~~~~~~~~~~~~
+!!! error TS2698: Type literals with spreads cannot contain index, call or construct signatures.
     callableConstructableSpread(12); // error, no call signature
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ x: number; }' has no compatible call signatures.

From a94fb2f5a3103b26eda73b02b0cb6554d371212f Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 24 Oct 2016 09:40:10 -0700
Subject: [PATCH 078/224] Explain writeSpreadType a little better

---
 src/compiler/checker.ts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index e19c779b35a84..cfe33252d67b8 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2338,6 +2338,8 @@ namespace ts {
                         inObjectTypeLiteral = saveInObjectTypeLiteral;
                     }
                     if (type.right.symbol === container) {
+                        // if type.right was written as part of the spread type, don't surround with ...{ }.
+                        // this gives { a: number, ... T } instead of { ...{ a: number }, ...T }
                         const saveInObjectTypeLiteral = inObjectTypeLiteral;
                         inObjectTypeLiteral = true;
                         writeObjectLiteralType(resolveStructuredTypeMembers(type.right));

From 35be8c351cadbc0fcb63d7370316db7856c31331 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 24 Oct 2016 10:02:04 -0700
Subject: [PATCH 079/224] Add more commentary to getSpreadType

---
 src/compiler/checker.ts | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index cfe33252d67b8..2378c65f6c3ba 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5794,23 +5794,29 @@ namespace ts {
             return spread;
         }
 
+        /**
+         * Since the source of spread types are object literals and type literals, which are not binary,
+         * this function should be called in a left folding style, with left = previous result of getSpreadType
+         * and right = the new element to be spread.
+         */
         function getSpreadType(left: Type, right: Type, symbol: Symbol, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
-            // TODO: Reorder everything now that it's order independent, to be easier to read
             const id = getTypeListId([left, right]);
             if (id in spreadTypes) {
                 return spreadTypes[id];
             }
 
-            // non-spreadable types
+            // any spreads to any
             if (left.flags & TypeFlags.Any || right.flags & TypeFlags.Any) {
                 return anyType;
             }
+            // flatten intersections to objects if all member types are objects
             if (left.flags & TypeFlags.Intersection) {
                 left = resolveObjectIntersection(left as IntersectionType);
             }
             if (right.flags & TypeFlags.Intersection) {
                 right = resolveObjectIntersection(right as IntersectionType);
             }
+            // distribute unions
             if (left.flags & TypeFlags.Union) {
                 const spreads = map((left as UnionType).types,
                                     t => getSpreadType(t, right, symbol, aliasSymbol, aliasTypeArguments));
@@ -5821,7 +5827,14 @@ namespace ts {
                                     t => getSpreadType(left, t, symbol, aliasSymbol, aliasTypeArguments));
                 return getUnionType(spreads, /*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
             }
-            if (right.flags & TypeFlags.Primitive) {
+            // skip primitives
+            if (left.flags & TypeFlags.Primitive && right.flags & TypeFlags.Primitive) {
+                return emptyObjectType;
+            }
+            else if (left.flags & TypeFlags.Primitive) {
+                return right;
+            }
+            else if (right.flags & TypeFlags.Primitive) {
                 return left;
             }
 
@@ -5845,7 +5858,7 @@ namespace ts {
                 // (T ... U) ... V to T ... (U ... V)
                 const rspread = right as SpreadType;
                 if (rspread.left === emptyObjectType) {
-                    // U ... ({} ... T) => (U ... T)
+                    // ... U ... ({} ... T) => ... U ... T
                     return getSpreadType(left, rspread.right, symbol, aliasSymbol, aliasTypeArguments);
                 }
                 return getSpreadType(getSpreadType(left, rspread.left, symbol, aliasSymbol, aliasTypeArguments),

From ad881094208ea08f942618bf765fcca855f3280a Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 24 Oct 2016 15:24:26 -0700
Subject: [PATCH 080/224] Initial implementation of 'keyof T' type operator

---
 src/compiler/binder.ts             |  1 +
 src/compiler/checker.ts            | 25 ++++++++++++++++++++++++-
 src/compiler/declarationEmitter.ts |  8 ++++++++
 src/compiler/emitter.ts            |  8 ++++++++
 src/compiler/parser.ts             | 21 +++++++++++++++++++--
 src/compiler/scanner.ts            |  1 +
 src/compiler/transformers/ts.ts    |  2 ++
 src/compiler/types.ts              |  8 ++++++++
 8 files changed, 71 insertions(+), 3 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index a256b632fac26..714967d7f1326 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -3066,6 +3066,7 @@ namespace ts {
             case SyntaxKind.InterfaceDeclaration:
             case SyntaxKind.TypeAliasDeclaration:
             case SyntaxKind.ThisType:
+            case SyntaxKind.TypeOperator:
             case SyntaxKind.LiteralType:
                 // Types and signatures are TypeScript syntax, and exclude all other facts.
                 transformFlags = TransformFlags.AssertTypeScript;
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 5b85a932c0597..e964824ca6205 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5663,6 +5663,26 @@ namespace ts {
             return links.resolvedType;
         }
 
+        function getLiteralTypeFromPropertyName(prop: Symbol) {
+            return startsWith(prop.name, "__@") ? neverType : getLiteralTypeForText(TypeFlags.StringLiteral, unescapeIdentifier(prop.name));
+        }
+
+        function getKeyOfType(type: Type): Type {
+            if (getIndexInfoOfType(type, IndexKind.String)) {
+                return getUnionType([stringType, numberType]);
+            }
+            const propKeysType = getUnionType(map(getPropertiesOfType(type), getLiteralTypeFromPropertyName));
+            return getIndexInfoOfType(type, IndexKind.Number) ? getUnionType([numberType, propKeysType]) : propKeysType;
+        }
+
+        function getTypeFromTypeOperatorNode(node: TypeOperatorNode) {
+            const links = getNodeLinks(node);
+            if (!links.resolvedType) {
+                links.resolvedType = getKeyOfType(getTypeFromTypeNodeNoAlias(node.type));
+            }
+            return links.resolvedType;
+        }
+
         function getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node: Node, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
             const links = getNodeLinks(node);
             if (!links.resolvedType) {
@@ -5822,6 +5842,8 @@ namespace ts {
                 case SyntaxKind.JSDocTypeLiteral:
                 case SyntaxKind.JSDocFunctionType:
                     return getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node, aliasSymbol, aliasTypeArguments);
+                case SyntaxKind.TypeOperator:
+                    return getTypeFromTypeOperatorNode(<TypeOperatorNode>node);
                 // This function assumes that an identifier or qualified name is a type expression
                 // Callers should first ensure this by calling isTypeNode
                 case SyntaxKind.Identifier:
@@ -18225,7 +18247,8 @@ namespace ts {
                 case SyntaxKind.IntersectionType:
                     return checkUnionOrIntersectionType(<UnionOrIntersectionTypeNode>node);
                 case SyntaxKind.ParenthesizedType:
-                    return checkSourceElement((<ParenthesizedTypeNode>node).type);
+                case SyntaxKind.TypeOperator:
+                    return checkSourceElement((<ParenthesizedTypeNode | TypeOperatorNode>node).type);
                 case SyntaxKind.FunctionDeclaration:
                     return checkFunctionDeclaration(<FunctionDeclaration>node);
                 case SyntaxKind.Block:
diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index 6458183b23c90..6fa1bf118aacb 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -413,6 +413,8 @@ namespace ts {
                     return emitIntersectionType(<IntersectionTypeNode>type);
                 case SyntaxKind.ParenthesizedType:
                     return emitParenType(<ParenthesizedTypeNode>type);
+                case SyntaxKind.TypeOperator:
+                    return emitTypeOperator(<TypeOperatorNode>type);
                 case SyntaxKind.FunctionType:
                 case SyntaxKind.ConstructorType:
                     return emitSignatureDeclarationWithJsDocComments(<FunctionOrConstructorTypeNode>type);
@@ -506,6 +508,12 @@ namespace ts {
                 write(")");
             }
 
+            function emitTypeOperator(type: TypeOperatorNode) {
+                write(tokenToString(type.operator));
+                write(" ");
+                emitType(type.type);
+            }
+
             function emitTypeLiteral(type: TypeLiteralNode) {
                 write("{");
                 if (type.members.length) {
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 1051c9adca961..71b181b26af21 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -594,6 +594,8 @@ const _super = (function (geti, seti) {
                     return emitExpressionWithTypeArguments(<ExpressionWithTypeArguments>node);
                 case SyntaxKind.ThisType:
                     return emitThisType();
+                case SyntaxKind.TypeOperator:
+                    return emitTypeOperator(<TypeOperatorNode>node);
                 case SyntaxKind.LiteralType:
                     return emitLiteralType(<LiteralTypeNode>node);
 
@@ -1088,6 +1090,12 @@ const _super = (function (geti, seti) {
             write("this");
         }
 
+        function emitTypeOperator(node: TypeOperatorNode) {
+            writeTokenText(node.operator);
+            write(" ");
+            emit(node.type);
+        }
+
         function emitLiteralType(node: LiteralTypeNode) {
             emitExpression(node.literal);
         }
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 8cdbf956d42a8..404cabfae551c 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -134,7 +134,8 @@ namespace ts {
             case SyntaxKind.IntersectionType:
                 return visitNodes(cbNodes, (<UnionOrIntersectionTypeNode>node).types);
             case SyntaxKind.ParenthesizedType:
-                return visitNode(cbNode, (<ParenthesizedTypeNode>node).type);
+            case SyntaxKind.TypeOperator:
+                return visitNode(cbNode, (<ParenthesizedTypeNode | TypeOperatorNode>node).type);
             case SyntaxKind.LiteralType:
                 return visitNode(cbNode, (<LiteralTypeNode>node).literal);
             case SyntaxKind.ObjectBindingPattern:
@@ -2526,6 +2527,22 @@ namespace ts {
             return type;
         }
 
+        function parseTypeOperator(operator: SyntaxKind.KeyOfKeyword) {
+            const node = <TypeOperatorNode>createNode(SyntaxKind.TypeOperator);
+            parseExpected(operator);
+            node.operator = operator;
+            node.type = parseTypeOperatorOrHigher();
+            return finishNode(node);
+        }
+
+        function parseTypeOperatorOrHigher(): TypeNode {
+            switch (token()) {
+                case SyntaxKind.KeyOfKeyword:
+                    return parseTypeOperator(SyntaxKind.KeyOfKeyword);
+            }
+            return parseArrayTypeOrHigher();
+        }
+
         function parseUnionOrIntersectionType(kind: SyntaxKind, parseConstituentType: () => TypeNode, operator: SyntaxKind): TypeNode {
             let type = parseConstituentType();
             if (token() === operator) {
@@ -2542,7 +2559,7 @@ namespace ts {
         }
 
         function parseIntersectionTypeOrHigher(): TypeNode {
-            return parseUnionOrIntersectionType(SyntaxKind.IntersectionType, parseArrayTypeOrHigher, SyntaxKind.AmpersandToken);
+            return parseUnionOrIntersectionType(SyntaxKind.IntersectionType, parseTypeOperatorOrHigher, SyntaxKind.AmpersandToken);
         }
 
         function parseUnionTypeOrHigher(): TypeNode {
diff --git a/src/compiler/scanner.ts b/src/compiler/scanner.ts
index ab76c7ffa19a4..d0b051049de38 100644
--- a/src/compiler/scanner.ts
+++ b/src/compiler/scanner.ts
@@ -90,6 +90,7 @@ namespace ts {
         "instanceof": SyntaxKind.InstanceOfKeyword,
         "interface": SyntaxKind.InterfaceKeyword,
         "is": SyntaxKind.IsKeyword,
+        "keyof": SyntaxKind.KeyOfKeyword,
         "let": SyntaxKind.LetKeyword,
         "module": SyntaxKind.ModuleKeyword,
         "namespace": SyntaxKind.NamespaceKeyword,
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 925869da3857f..4c8e79703e743 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -288,6 +288,7 @@ namespace ts {
                 case SyntaxKind.IntersectionType:
                 case SyntaxKind.ParenthesizedType:
                 case SyntaxKind.ThisType:
+                case SyntaxKind.TypeOperator:
                 case SyntaxKind.LiteralType:
                     // TypeScript type nodes are elided.
 
@@ -1856,6 +1857,7 @@ namespace ts {
                     }
                     // Fallthrough
                 case SyntaxKind.TypeQuery:
+                case SyntaxKind.TypeOperator:
                 case SyntaxKind.TypeLiteral:
                 case SyntaxKind.AnyKeyword:
                 case SyntaxKind.ThisType:
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index f9ec3e9f268cc..b1299fc01fa9d 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -168,6 +168,7 @@ namespace ts {
         DeclareKeyword,
         GetKeyword,
         IsKeyword,
+        KeyOfKeyword,
         ModuleKeyword,
         NamespaceKeyword,
         NeverKeyword,
@@ -216,6 +217,7 @@ namespace ts {
         IntersectionType,
         ParenthesizedType,
         ThisType,
+        TypeOperator,
         LiteralType,
         // Binding patterns
         ObjectBindingPattern,
@@ -870,6 +872,12 @@ namespace ts {
         type: TypeNode;
     }
 
+    export interface TypeOperatorNode extends TypeNode {
+        kind: SyntaxKind.TypeOperator;
+        operator: SyntaxKind.KeyOfKeyword;
+        type: TypeNode;
+    }
+
     export interface LiteralTypeNode extends TypeNode {
         kind: SyntaxKind.LiteralType;
         literal: Expression;

From 07478aae149fbb94aca2c13a2cb497dc6dd2f1e9 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Tue, 25 Oct 2016 06:35:35 -0700
Subject: [PATCH 081/224] Introduce PropertyNameType

---
 src/compiler/checker.ts | 26 ++++++++++++++++++++------
 src/compiler/types.ts   | 17 ++++++++++++-----
 2 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index e964824ca6205..bc42d7be3a152 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2219,6 +2219,11 @@ namespace ts {
                     else if (type.flags & TypeFlags.StringOrNumberLiteral) {
                         writer.writeStringLiteral(literalTypeToString(<LiteralType>type));
                     }
+                    else if (type.flags & TypeFlags.PropertyName) {
+                        writer.writeKeyword("keyof");
+                        writeSpace(writer);
+                        writeType((<PropertyNameType>type).type, TypeFormatFlags.None);
+                    }
                     else {
                         // Should never get here
                         // { ... }
@@ -5667,18 +5672,24 @@ namespace ts {
             return startsWith(prop.name, "__@") ? neverType : getLiteralTypeForText(TypeFlags.StringLiteral, unescapeIdentifier(prop.name));
         }
 
-        function getKeyOfType(type: Type): Type {
-            if (getIndexInfoOfType(type, IndexKind.String)) {
-                return getUnionType([stringType, numberType]);
+        function getPropertyNameTypeForTypeParameter(type: TypeParameter) {
+            if (!type.resolvedPropertyNameType) {
+                type.resolvedPropertyNameType = <PropertyNameType>createType(TypeFlags.PropertyName);
+                type.resolvedPropertyNameType.type = type;
             }
-            const propKeysType = getUnionType(map(getPropertiesOfType(type), getLiteralTypeFromPropertyName));
-            return getIndexInfoOfType(type, IndexKind.Number) ? getUnionType([numberType, propKeysType]) : propKeysType;
+            return type.resolvedPropertyNameType;
+        }
+
+        function getPropertyNameType(type: Type): Type {
+            return type.flags & TypeFlags.TypeParameter ?
+                getPropertyNameTypeForTypeParameter(<TypeParameter>type) :
+                getUnionType(map(getPropertiesOfType(type), getLiteralTypeFromPropertyName));
         }
 
         function getTypeFromTypeOperatorNode(node: TypeOperatorNode) {
             const links = getNodeLinks(node);
             if (!links.resolvedType) {
-                links.resolvedType = getKeyOfType(getTypeFromTypeNodeNoAlias(node.type));
+                links.resolvedType = getPropertyNameType(getTypeFromTypeNodeNoAlias(node.type));
             }
             return links.resolvedType;
         }
@@ -6105,6 +6116,9 @@ namespace ts {
                 if (type.flags & TypeFlags.Intersection) {
                     return getIntersectionType(instantiateList((<IntersectionType>type).types, mapper, instantiateType), type.aliasSymbol, mapper.targetTypes);
                 }
+                if (type.flags & TypeFlags.PropertyName) {
+                    return getPropertyNameType(instantiateType((<PropertyNameType>type).type, mapper));
+                }
             }
             return type;
         }
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index b1299fc01fa9d..1d61e79c77518 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2623,14 +2623,15 @@ namespace ts {
         Object                  = 1 << 15,  // Object type
         Union                   = 1 << 16,  // Union (T | U)
         Intersection            = 1 << 17,  // Intersection (T & U)
+        PropertyName            = 1 << 18,  // keyof T
         /* @internal */
-        FreshLiteral            = 1 << 18,  // Fresh literal type
+        FreshLiteral            = 1 << 19,  // Fresh literal type
         /* @internal */
-        ContainsWideningType    = 1 << 19,  // Type is or contains undefined or null widening type
+        ContainsWideningType    = 1 << 20,  // Type is or contains undefined or null widening type
         /* @internal */
-        ContainsObjectLiteral   = 1 << 20,  // Type is or contains object literal type
+        ContainsObjectLiteral   = 1 << 21,  // Type is or contains object literal type
         /* @internal */
-        ContainsAnyFunctionType = 1 << 21,  // Type is or contains object literal type
+        ContainsAnyFunctionType = 1 << 22,  // Type is or contains object literal type
 
         /* @internal */
         Nullable = Undefined | Null,
@@ -2643,7 +2644,7 @@ namespace ts {
         Intrinsic = Any | String | Number | Boolean | BooleanLiteral | ESSymbol | Void | Undefined | Null | Never,
         /* @internal */
         Primitive = String | Number | Boolean | Enum | ESSymbol | Void | Undefined | Null | Literal,
-        StringLike = String | StringLiteral,
+        StringLike = String | StringLiteral | PropertyName,
         NumberLike = Number | NumberLiteral | Enum | EnumLiteral,
         BooleanLike = Boolean | BooleanLiteral,
         EnumLike = Enum | EnumLiteral,
@@ -2816,9 +2817,15 @@ namespace ts {
         /* @internal */
         resolvedApparentType: Type;
         /* @internal */
+        resolvedPropertyNameType: PropertyNameType;
+        /* @internal */
         isThisType?: boolean;
     }
 
+    export interface PropertyNameType extends Type {
+        type: TypeParameter;
+    }
+
     export const enum SignatureKind {
         Call,
         Construct,

From dc99355b5d44c5d2122c1262c3c1bb56e1a788a5 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Tue, 25 Oct 2016 08:02:16 -0700
Subject: [PATCH 082/224] Move most of resolveModuleNameForLsHost to lsHost

---
 src/compiler/moduleNameResolver.ts | 50 ++++++++++--------------------
 src/server/lsHost.ts               | 14 ++++++++-
 2 files changed, 30 insertions(+), 34 deletions(-)

diff --git a/src/compiler/moduleNameResolver.ts b/src/compiler/moduleNameResolver.ts
index f518070ad19b9..33b1db24fcecb 100644
--- a/src/compiler/moduleNameResolver.ts
+++ b/src/compiler/moduleNameResolver.ts
@@ -7,8 +7,7 @@ namespace ts {
         host.trace(formatMessage.apply(undefined, arguments));
     }
 
-    /* @internal */
-    export function isTraceEnabled(compilerOptions: CompilerOptions, host: ModuleResolutionHost): boolean {
+    function isTraceEnabled(compilerOptions: CompilerOptions, host: ModuleResolutionHost): boolean {
         return compilerOptions.traceResolution && host.trace !== undefined;
     }
 
@@ -79,37 +78,6 @@ namespace ts {
         traceEnabled: boolean;
     }
 
-    /** LsHost uses a global cache of automatically-installed typings to help it resolve modules. */
-    /* @internal */
-    export function resolveModuleNameForLsHost(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost, globalCache: string | undefined, projectName: string): ResolvedModuleWithFailedLookupLocations {
-        const primaryResult = resolveModuleName(moduleName, containingFile, compilerOptions, host);
-        if (primaryResult.resolvedModule && primaryResult.resolvedModule.resolvedTsFileName) {
-            // return result immediately only if it is .ts, .tsx or .d.ts
-            // otherwise try to load typings from @types
-            return primaryResult;
-        }
-
-        // create different collection of failed lookup locations for second pass
-        // if it will fail and we've already found something during the first pass - we don't want to pollute its results
-        const secondaryLookupFailedLookupLocations: string[] = [];
-        if (globalCache !== undefined) {
-            const traceEnabled = isTraceEnabled(compilerOptions, host);
-            if (traceEnabled) {
-                trace(host, Diagnostics.Auto_discovery_for_typings_is_enabled_in_project_0_Running_extra_resolution_pass_for_module_1_using_cache_location_2, projectName, moduleName, globalCache);
-            }
-            const state: ModuleResolutionState = { compilerOptions, host, traceEnabled };
-            const resolved = loadModuleFromNodeModules(Extensions.All, moduleName, globalCache, secondaryLookupFailedLookupLocations, state, /*checkOneLevel*/ true);
-            if (resolved) {
-                return createResolvedModuleWithFailedLookupLocations(resolved, /*isExternalLibraryImport*/ true, primaryResult.failedLookupLocations.concat(secondaryLookupFailedLookupLocations));
-            }
-        }
-
-        if (!primaryResult.resolvedModule && secondaryLookupFailedLookupLocations.length) {
-            primaryResult.failedLookupLocations = primaryResult.failedLookupLocations.concat(secondaryLookupFailedLookupLocations);
-        }
-        return primaryResult;
-    }
-
     function tryReadTypesSection(packageJsonPath: string, baseDirectory: string, state: ModuleResolutionState): string {
         const jsonContent = readJson(packageJsonPath, state.host);
 
@@ -850,4 +818,20 @@ namespace ts {
             containingDirectory = parentPath;
         }
     }
+
+    /**
+     * LSHost may load a module from a global cache of typings.
+     * This is the minumum code needed to expose that functionality; the rest is in LSHost.
+     */
+    /* @internal */
+    export function loadModuleFromGlobalCache(moduleName: string, projectName: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost, globalCache: string): ResolvedModuleWithFailedLookupLocations {
+        const traceEnabled = isTraceEnabled(compilerOptions, host);
+        if (traceEnabled) {
+            trace(host, Diagnostics.Auto_discovery_for_typings_is_enabled_in_project_0_Running_extra_resolution_pass_for_module_1_using_cache_location_2, projectName, moduleName, globalCache);
+        }
+        const state: ModuleResolutionState = { compilerOptions, host, traceEnabled };
+        const failedLookupLocations: string[] = [];
+        const resolved = loadModuleFromNodeModules(Extensions.All, moduleName, globalCache, failedLookupLocations, state, /*checkOneLevel*/ true);
+        return createResolvedModuleWithFailedLookupLocations(resolved, /*isExternalLibraryImport*/ true, failedLookupLocations);
+    }
 }
\ No newline at end of file
diff --git a/src/server/lsHost.ts b/src/server/lsHost.ts
index d6dfb67ed04b7..c95b834b8ebf6 100644
--- a/src/server/lsHost.ts
+++ b/src/server/lsHost.ts
@@ -23,7 +23,19 @@ namespace ts.server {
                 const globalCache = this.project.getTypingOptions().enableAutoDiscovery
                     ? this.project.projectService.typingsInstaller.globalTypingsCacheLocation
                     : undefined;
-                return resolveModuleNameForLsHost(moduleName, containingFile, compilerOptions, host, globalCache, this.project.getProjectName());
+                const primaryResult = resolveModuleName(moduleName, containingFile, compilerOptions, host);
+                // return result immediately only if it is .ts, .tsx or .d.ts
+                if (!(primaryResult.resolvedModule && primaryResult.resolvedModule.resolvedTsFileName) && globalCache !== undefined) {
+                    // otherwise try to load typings from @types
+
+                    // create different collection of failed lookup locations for second pass
+                    // if it will fail and we've already found something during the first pass - we don't want to pollute its results
+                    const { resolvedModule, failedLookupLocations } = loadModuleFromGlobalCache(moduleName, this.project.getProjectName(), compilerOptions, host, globalCache);
+                    if (resolvedModule) {
+                        return { resolvedModule, failedLookupLocations: primaryResult.failedLookupLocations.concat(failedLookupLocations) };
+                    }
+                }
+                return primaryResult;
             };
         }
 

From 1b15646c4195acf4221e5a7698d651854891a66b Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Tue, 25 Oct 2016 08:13:07 -0700
Subject: [PATCH 083/224] Simplify isImplicitGlob test

---
 src/compiler/core.ts    | 8 ++++++--
 src/compiler/program.ts | 4 ----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 1eb0614a8a391..3ee4e57727223 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -1448,6 +1448,10 @@ namespace ts {
         return expectedPos >= 0 && str.indexOf(suffix, expectedPos) === expectedPos;
     }
 
+    export function hasExtension(fileName: string): boolean {
+        return getBaseFileName(fileName).indexOf(".") >= 0;
+    }
+
     export function fileExtensionIs(path: string, extension: string): boolean {
         return path.length > extension.length && endsWith(path, extension);
     }
@@ -1708,8 +1712,8 @@ namespace ts {
     function getIncludeBasePath(absolute: string): string {
         const wildcardOffset = indexOfAnyCharCode(absolute, wildcardCharCodes);
         if (wildcardOffset < 0) {
-            // No "*" in the path
-            return isImplicitGlob(getBasename(absolute))
+            // No "*" or "?" in the path
+            return !hasExtension(absolute)
                 ? absolute
                 : removeTrailingDirectorySeparator(getDirectoryPath(absolute));
         }
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index a52ffc85452ef..7af5630158392 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -972,10 +972,6 @@ namespace ts {
             return sortAndDeduplicateDiagnostics(allDiagnostics);
         }
 
-        function hasExtension(fileName: string): boolean {
-            return getBaseFileName(fileName).indexOf(".") >= 0;
-        }
-
         function processRootFile(fileName: string, isDefaultLib: boolean) {
             processSourceFile(normalizePath(fileName), isDefaultLib, /*isReference*/ true);
         }

From c21592ede15454bf3dbea735250a38c94d867726 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Tue, 25 Oct 2016 14:32:20 -0700
Subject: [PATCH 084/224] Initial implementation of 'T[K]' property access
 types

---
 src/compiler/binder.ts               |  1 +
 src/compiler/checker.ts              | 68 +++++++++++++++++++++++++++-
 src/compiler/declarationEmitter.ts   |  9 ++++
 src/compiler/diagnosticMessages.json |  4 ++
 src/compiler/emitter.ts              |  9 ++++
 src/compiler/parser.ts               | 20 ++++++--
 src/compiler/transformers/ts.ts      |  2 +
 src/compiler/types.ts                | 25 ++++++++--
 8 files changed, 127 insertions(+), 11 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 714967d7f1326..5318595aecae7 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -3067,6 +3067,7 @@ namespace ts {
             case SyntaxKind.TypeAliasDeclaration:
             case SyntaxKind.ThisType:
             case SyntaxKind.TypeOperator:
+            case SyntaxKind.PropertyAccessType:
             case SyntaxKind.LiteralType:
                 // Types and signatures are TypeScript syntax, and exclude all other facts.
                 transformFlags = TransformFlags.AssertTypeScript;
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index bc42d7be3a152..0f18c795ae396 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2222,7 +2222,13 @@ namespace ts {
                     else if (type.flags & TypeFlags.PropertyName) {
                         writer.writeKeyword("keyof");
                         writeSpace(writer);
-                        writeType((<PropertyNameType>type).type, TypeFormatFlags.None);
+                        writeType((<PropertyNameType>type).type, TypeFormatFlags.InElementType);
+                    }
+                    else if (type.flags & TypeFlags.PropertyAccess) {
+                        writeType((<PropertyAccessType>type).objectType, TypeFormatFlags.InElementType);
+                        writePunctuation(writer, SyntaxKind.OpenBracketToken);
+                        writeType((<PropertyAccessType>type).keyType, TypeFormatFlags.None);
+                        writePunctuation(writer, SyntaxKind.CloseBracketToken);
                     }
                     else {
                         // Should never get here
@@ -5694,6 +5700,55 @@ namespace ts {
             return links.resolvedType;
         }
 
+        function createPropertyAccessType(objectType: Type, keyType: TypeParameter) {
+            const type = <PropertyAccessType>createType(TypeFlags.PropertyAccess);
+            type.objectType = objectType;
+            type.keyType = keyType;
+            return type;
+        }
+
+        function getPropertyAccessTypeForTypeParameter(objectType: Type, keyType: TypeParameter) {
+            const propertyAccessTypes = keyType.resolvedPropertyAccessTypes || (keyType.resolvedPropertyAccessTypes = []);
+            return propertyAccessTypes[objectType.id] || (propertyAccessTypes[objectType.id] = createPropertyAccessType(objectType, keyType));
+        }
+
+        function getPropertyAccessType(objectType: Type, keyType: Type) {
+            if (keyType.flags & TypeFlags.TypeParameter) {
+                return getPropertyAccessTypeForTypeParameter(objectType, <TypeParameter>keyType);
+            }
+            if (isTypeOfKind(keyType, TypeFlags.StringLiteral) && !(keyType.flags & TypeFlags.Intersection)) {
+                return mapType(keyType, t => getTypeOfPropertyOfType(objectType, escapeIdentifier((<LiteralType>t).text)) || unknownType);
+            }
+            return keyType.flags & TypeFlags.Any ? anyType : unknownType;
+        }
+
+        function resolvePropertyAccessTypeNode(node: PropertyAccessTypeNode) {
+            const objectType = getTypeFromTypeNodeNoAlias(node.objectType);
+            const keyType = getTypeFromTypeNodeNoAlias(node.keyType);
+            if (keyType.flags & TypeFlags.TypeParameter &&
+                getConstraintOfTypeParameter(<TypeParameter>keyType) === getPropertyNameType(objectType)) {
+                return getPropertyAccessType(objectType, keyType);
+            }
+            if (isTypeOfKind(keyType, TypeFlags.StringLiteral) && !(keyType.flags & TypeFlags.Intersection)) {
+                const missing = forEachType(keyType, t => getTypeOfPropertyOfType(objectType, escapeIdentifier((<LiteralType>t).text)) ? undefined : (<LiteralType>t).text);
+                if (missing) {
+                    error(node.keyType, Diagnostics.Property_0_is_missing_in_type_1, missing, typeToString(objectType));
+                    return unknownType;
+                }
+                return getPropertyAccessType(objectType, keyType);
+            }
+            error(node.keyType, Diagnostics.Property_access_element_type_must_be_a_string_literal_type_or_a_type_parameter_constrained_to_keyof_0, typeToString(objectType));
+            return unknownType;
+        }
+
+        function getTypeFromPropertyAccessTypeNode(node: PropertyAccessTypeNode) {
+            const links = getNodeLinks(node);
+            if (!links.resolvedType) {
+                links.resolvedType = resolvePropertyAccessTypeNode(node);
+            }
+            return links.resolvedType;
+        }
+
         function getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node: Node, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
             const links = getNodeLinks(node);
             if (!links.resolvedType) {
@@ -5855,6 +5910,8 @@ namespace ts {
                     return getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node, aliasSymbol, aliasTypeArguments);
                 case SyntaxKind.TypeOperator:
                     return getTypeFromTypeOperatorNode(<TypeOperatorNode>node);
+                case SyntaxKind.PropertyAccessType:
+                    return getTypeFromPropertyAccessTypeNode(<PropertyAccessTypeNode>node);
                 // This function assumes that an identifier or qualified name is a type expression
                 // Callers should first ensure this by calling isTypeNode
                 case SyntaxKind.Identifier:
@@ -6119,6 +6176,9 @@ namespace ts {
                 if (type.flags & TypeFlags.PropertyName) {
                     return getPropertyNameType(instantiateType((<PropertyNameType>type).type, mapper));
                 }
+                if (type.flags & TypeFlags.PropertyAccess) {
+                    return getPropertyAccessType(instantiateType((<PropertyAccessType>type).objectType, mapper), instantiateType((<PropertyAccessType>type).keyType, mapper));
+                }
             }
             return type;
         }
@@ -8054,7 +8114,7 @@ namespace ts {
 
         function hasPrimitiveConstraint(type: TypeParameter): boolean {
             const constraint = getConstraintOfTypeParameter(type);
-            return constraint && maybeTypeOfKind(constraint, TypeFlags.Primitive);
+            return constraint && maybeTypeOfKind(constraint, TypeFlags.Primitive | TypeFlags.PropertyName);
         }
 
         function getInferredType(context: InferenceContext, index: number): Type {
@@ -8546,6 +8606,10 @@ namespace ts {
             return containsType(target.types, source);
         }
 
+        function forEachType<T>(type: Type, f: (t: Type) => T): T {
+            return type.flags & TypeFlags.Union ? forEach((<UnionType>type).types, f) : f(type);
+        }
+
         function filterType(type: Type, f: (t: Type) => boolean): Type {
             if (type.flags & TypeFlags.Union) {
                 const types = (<UnionType>type).types;
diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index 6fa1bf118aacb..271e020c3896b 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -415,6 +415,8 @@ namespace ts {
                     return emitParenType(<ParenthesizedTypeNode>type);
                 case SyntaxKind.TypeOperator:
                     return emitTypeOperator(<TypeOperatorNode>type);
+                case SyntaxKind.PropertyAccessType:
+                    return emitPropertyAccessType(<PropertyAccessTypeNode>type);
                 case SyntaxKind.FunctionType:
                 case SyntaxKind.ConstructorType:
                     return emitSignatureDeclarationWithJsDocComments(<FunctionOrConstructorTypeNode>type);
@@ -514,6 +516,13 @@ namespace ts {
                 emitType(type.type);
             }
 
+            function emitPropertyAccessType(node: PropertyAccessTypeNode) {
+                emitType(node.objectType);
+                write("[");
+                emitType(node.keyType);
+                write("]");
+            }
+
             function emitTypeLiteral(type: TypeLiteralNode) {
                 write("{");
                 if (type.members.length) {
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 21f04da488d9b..81882e0c3bba2 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1751,6 +1751,10 @@
         "category": "Error",
         "code": 2535
     },
+    "Property access element type must be a string literal type or a type parameter constrained to 'keyof {0}'.": {
+        "category": "Error",
+        "code": 2536
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 71b181b26af21..dde921765dfa2 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -596,6 +596,8 @@ const _super = (function (geti, seti) {
                     return emitThisType();
                 case SyntaxKind.TypeOperator:
                     return emitTypeOperator(<TypeOperatorNode>node);
+                case SyntaxKind.PropertyAccessType:
+                    return emitPropertyAccessType(<PropertyAccessTypeNode>node);
                 case SyntaxKind.LiteralType:
                     return emitLiteralType(<LiteralTypeNode>node);
 
@@ -1096,6 +1098,13 @@ const _super = (function (geti, seti) {
             emit(node.type);
         }
 
+        function emitPropertyAccessType(node: PropertyAccessTypeNode) {
+            emit(node.objectType);
+            write("[");
+            emit(node.keyType);
+            write("]");
+        }
+
         function emitLiteralType(node: LiteralTypeNode) {
             emitExpression(node.literal);
         }
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 404cabfae551c..8fadb259184df 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -136,6 +136,9 @@ namespace ts {
             case SyntaxKind.ParenthesizedType:
             case SyntaxKind.TypeOperator:
                 return visitNode(cbNode, (<ParenthesizedTypeNode | TypeOperatorNode>node).type);
+            case SyntaxKind.PropertyAccessType:
+                return visitNode(cbNode, (<PropertyAccessTypeNode>node).objectType) ||
+                    visitNode(cbNode, (<PropertyAccessTypeNode>node).keyType);
             case SyntaxKind.LiteralType:
                 return visitNode(cbNode, (<LiteralTypeNode>node).literal);
             case SyntaxKind.ObjectBindingPattern:
@@ -2519,10 +2522,19 @@ namespace ts {
         function parseArrayTypeOrHigher(): TypeNode {
             let type = parseNonArrayType();
             while (!scanner.hasPrecedingLineBreak() && parseOptional(SyntaxKind.OpenBracketToken)) {
-                parseExpected(SyntaxKind.CloseBracketToken);
-                const node = <ArrayTypeNode>createNode(SyntaxKind.ArrayType, type.pos);
-                node.elementType = type;
-                type = finishNode(node);
+                if (isStartOfType()) {
+                    const node = <PropertyAccessTypeNode>createNode(SyntaxKind.PropertyAccessType, type.pos);
+                    node.objectType = type;
+                    node.keyType = parseType();
+                    parseExpected(SyntaxKind.CloseBracketToken);
+                    type = finishNode(node);
+                }
+                else {
+                    const node = <ArrayTypeNode>createNode(SyntaxKind.ArrayType, type.pos);
+                    node.elementType = type;
+                    parseExpected(SyntaxKind.CloseBracketToken);
+                    type = finishNode(node);
+                }
             }
             return type;
         }
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 4c8e79703e743..6b0c92e3c8ea9 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -289,6 +289,7 @@ namespace ts {
                 case SyntaxKind.ParenthesizedType:
                 case SyntaxKind.ThisType:
                 case SyntaxKind.TypeOperator:
+                case SyntaxKind.PropertyAccessType:
                 case SyntaxKind.LiteralType:
                     // TypeScript type nodes are elided.
 
@@ -1858,6 +1859,7 @@ namespace ts {
                     // Fallthrough
                 case SyntaxKind.TypeQuery:
                 case SyntaxKind.TypeOperator:
+                case SyntaxKind.PropertyAccessType:
                 case SyntaxKind.TypeLiteral:
                 case SyntaxKind.AnyKeyword:
                 case SyntaxKind.ThisType:
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 1d61e79c77518..3912c6e464278 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -218,6 +218,7 @@ namespace ts {
         ParenthesizedType,
         ThisType,
         TypeOperator,
+        PropertyAccessType,
         LiteralType,
         // Binding patterns
         ObjectBindingPattern,
@@ -878,6 +879,12 @@ namespace ts {
         type: TypeNode;
     }
 
+    export interface PropertyAccessTypeNode extends TypeNode {
+        kind: SyntaxKind.PropertyAccessType;
+        objectType: TypeNode;
+        keyType: TypeNode;
+    }
+
     export interface LiteralTypeNode extends TypeNode {
         kind: SyntaxKind.LiteralType;
         literal: Expression;
@@ -2624,14 +2631,15 @@ namespace ts {
         Union                   = 1 << 16,  // Union (T | U)
         Intersection            = 1 << 17,  // Intersection (T & U)
         PropertyName            = 1 << 18,  // keyof T
+        PropertyAccess          = 1 << 19,  // T[K]
         /* @internal */
-        FreshLiteral            = 1 << 19,  // Fresh literal type
+        FreshLiteral            = 1 << 20,  // Fresh literal type
         /* @internal */
-        ContainsWideningType    = 1 << 20,  // Type is or contains undefined or null widening type
+        ContainsWideningType    = 1 << 21,  // Type is or contains undefined or null widening type
         /* @internal */
-        ContainsObjectLiteral   = 1 << 21,  // Type is or contains object literal type
+        ContainsObjectLiteral   = 1 << 22,  // Type is or contains object literal type
         /* @internal */
-        ContainsAnyFunctionType = 1 << 22,  // Type is or contains object literal type
+        ContainsAnyFunctionType = 1 << 23,  // Type is or contains object literal type
 
         /* @internal */
         Nullable = Undefined | Null,
@@ -2654,7 +2662,7 @@ namespace ts {
 
         // 'Narrowable' types are types where narrowing actually narrows.
         // This *should* be every type other than null, undefined, void, and never
-        Narrowable = Any | StructuredType | TypeParameter | StringLike | NumberLike | BooleanLike | ESSymbol,
+        Narrowable = Any | StructuredType | TypeParameter | PropertyAccess | StringLike | NumberLike | BooleanLike | ESSymbol,
         NotUnionOrUnit = Any | ESSymbol | Object,
         /* @internal */
         RequiresWidening = ContainsWideningType | ContainsObjectLiteral,
@@ -2819,6 +2827,8 @@ namespace ts {
         /* @internal */
         resolvedPropertyNameType: PropertyNameType;
         /* @internal */
+        resolvedPropertyAccessTypes: PropertyAccessType[];
+        /* @internal */
         isThisType?: boolean;
     }
 
@@ -2826,6 +2836,11 @@ namespace ts {
         type: TypeParameter;
     }
 
+    export interface PropertyAccessType extends Type {
+        objectType: Type;
+        keyType: TypeParameter;
+    }
+
     export const enum SignatureKind {
         Call,
         Construct,

From f6b82d5e9ff4ee5a9e2188536b9d6dcf57d3c893 Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Tue, 25 Oct 2016 16:36:02 -0700
Subject: [PATCH 085/224] add a fallback logic for older versions of node that
 don't support 'homedir' (#11845)

* add a fallback logic for older versions of node that don't support 'homedir'

* try os.homedir first
---
 src/server/server.ts | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/src/server/server.ts b/src/server/server.ts
index 4bab628f9a534..5057a13dbd1bc 100644
--- a/src/server/server.ts
+++ b/src/server/server.ts
@@ -14,21 +14,33 @@ namespace ts.server {
     } = require("child_process");
 
     const os: {
-        homedir(): string
+        homedir?(): string;
+        tmpdir(): string;
     } = require("os");
 
-
     function getGlobalTypingsCacheLocation() {
         let basePath: string;
         switch (process.platform) {
             case "win32":
-                basePath = process.env.LOCALAPPDATA || process.env.APPDATA || os.homedir();
+                basePath = process.env.LOCALAPPDATA ||
+                    process.env.APPDATA ||
+                    (os.homedir && os.homedir()) ||
+                    process.env.USERPROFILE ||
+                    (process.env.HOMEDRIVE && process.env.HOMEPATH && normalizeSlashes(process.env.HOMEDRIVE + process.env.HOMEPATH)) ||
+                    os.tmpdir();
                 break;
             case "linux":
-                basePath = os.homedir();
+                basePath = (os.homedir && os.homedir()) ||
+                    process.env.HOME ||
+                    ((process.env.LOGNAME || process.env.USER) && `/home/${process.env.LOGNAME || process.env.USER}`) ||
+                    os.tmpdir();
                 break;
             case "darwin":
-                basePath = combinePaths(os.homedir(), "Library/Application Support/");
+                const homeDir = (os.homedir && os.homedir()) ||
+                        process.env.HOME ||
+                        ((process.env.LOGNAME || process.env.USER) && `/Users/${process.env.LOGNAME || process.env.USER}`) ||
+                        os.tmpdir();
+                basePath = combinePaths(homeDir, "Library/Application Support/");
                 break;
         }
 

From 1b16c0b94b299aefd80ea647cfddda5340e35397 Mon Sep 17 00:00:00 2001
From: Jason Ramsay <jasonra@microsoft.com>
Date: Mon, 24 Oct 2016 16:57:43 -0700
Subject: [PATCH 086/224] For JavaScript files, we report semantic errors for
 using TypeScript-only constructs 
from within a JavaScript file as syntactic
 errors.

---
 src/compiler/program.ts                       | 16 +++++---
 src/compiler/types.ts                         |  3 ++
 ... => getJavaScriptSyntacticDiagnostics1.ts} |  2 +-
 ...=> getJavaScriptSyntacticDiagnostics10.ts} |  2 +-
 ...=> getJavaScriptSyntacticDiagnostics11.ts} |  2 +-
 ...=> getJavaScriptSyntacticDiagnostics12.ts} |  2 +-
 ...=> getJavaScriptSyntacticDiagnostics13.ts} |  2 +-
 ...=> getJavaScriptSyntacticDiagnostics14.ts} |  2 +-
 ...=> getJavaScriptSyntacticDiagnostics15.ts} |  2 +-
 ...=> getJavaScriptSyntacticDiagnostics16.ts} |  2 +-
 ...=> getJavaScriptSyntacticDiagnostics17.ts} |  2 +-
 ...=> getJavaScriptSyntacticDiagnostics18.ts} |  4 +-
 ...=> getJavaScriptSyntacticDiagnostics19.ts} |  2 +-
 ... => getJavaScriptSyntacticDiagnostics2.ts} |  2 +-
 ...=> getJavaScriptSyntacticDiagnostics21.ts} |  0
 ...=> getJavaScriptSyntacticDiagnostics22.ts} |  0
 ...=> getJavaScriptSyntacticDiagnostics23.ts} |  0
 ...=> getJavaScriptSyntacticDiagnostics24.ts} |  0
 ... => getJavaScriptSyntacticDiagnostics3.ts} |  2 +-
 ... => getJavaScriptSyntacticDiagnostics4.ts} |  2 +-
 ... => getJavaScriptSyntacticDiagnostics5.ts} |  2 +-
 ... => getJavaScriptSyntacticDiagnostics6.ts} |  2 +-
 ... => getJavaScriptSyntacticDiagnostics7.ts} |  2 +-
 ... => getJavaScriptSyntacticDiagnostics8.ts} |  2 +-
 ... => getJavaScriptSyntacticDiagnostics9.ts} |  2 +-
 .../getJavaScriptSyntacticDiagnostics02.ts    | 40 +++++++++++++++++++
 26 files changed, 73 insertions(+), 26 deletions(-)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics1.ts => getJavaScriptSyntacticDiagnostics1.ts} (83%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics10.ts => getJavaScriptSyntacticDiagnostics10.ts} (84%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics11.ts => getJavaScriptSyntacticDiagnostics11.ts} (84%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics12.ts => getJavaScriptSyntacticDiagnostics12.ts} (83%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics13.ts => getJavaScriptSyntacticDiagnostics13.ts} (83%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics14.ts => getJavaScriptSyntacticDiagnostics14.ts} (83%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics15.ts => getJavaScriptSyntacticDiagnostics15.ts} (84%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics16.ts => getJavaScriptSyntacticDiagnostics16.ts} (83%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics17.ts => getJavaScriptSyntacticDiagnostics17.ts} (84%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics18.ts => getJavaScriptSyntacticDiagnostics18.ts} (86%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics19.ts => getJavaScriptSyntacticDiagnostics19.ts} (83%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics2.ts => getJavaScriptSyntacticDiagnostics2.ts} (83%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics21.ts => getJavaScriptSyntacticDiagnostics21.ts} (100%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics22.ts => getJavaScriptSyntacticDiagnostics22.ts} (100%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics23.ts => getJavaScriptSyntacticDiagnostics23.ts} (100%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics24.ts => getJavaScriptSyntacticDiagnostics24.ts} (100%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics3.ts => getJavaScriptSyntacticDiagnostics3.ts} (84%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics4.ts => getJavaScriptSyntacticDiagnostics4.ts} (83%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics5.ts => getJavaScriptSyntacticDiagnostics5.ts} (84%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics6.ts => getJavaScriptSyntacticDiagnostics6.ts} (84%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics7.ts => getJavaScriptSyntacticDiagnostics7.ts} (84%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics8.ts => getJavaScriptSyntacticDiagnostics8.ts} (83%)
 rename tests/cases/fourslash/{getJavaScriptSemanticDiagnostics9.ts => getJavaScriptSyntacticDiagnostics9.ts} (84%)
 create mode 100644 tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index a9c64f3ecbe3a..6c06664d5898d 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -725,6 +725,12 @@ namespace ts {
         }
 
         function getSyntacticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
+            // For JavaScript files, we report semantic errors for using TypeScript-only
+            // constructs from within a JavaScript file as syntactic errors.
+            if (isSourceFileJavaScript(sourceFile) && !sourceFile.parseJavaScriptDiagnostics) {
+                sourceFile.parseJavaScriptDiagnostics = getJavaScriptSemanticDiagnosticsForFile(sourceFile);
+                sourceFile.parseDiagnostics = sourceFile.parseDiagnostics.concat(sourceFile.parseJavaScriptDiagnostics);
+            }
             return sourceFile.parseDiagnostics;
         }
 
@@ -757,12 +763,10 @@ namespace ts {
 
                 Debug.assert(!!sourceFile.bindDiagnostics);
                 const bindDiagnostics = sourceFile.bindDiagnostics;
-                // For JavaScript files, we don't want to report the normal typescript semantic errors.
-                // Instead, we just report errors for using TypeScript-only constructs from within a
-                // JavaScript file.
-                const checkDiagnostics = isSourceFileJavaScript(sourceFile) ?
-                    getJavaScriptSemanticDiagnosticsForFile(sourceFile) :
-                    typeChecker.getDiagnostics(sourceFile, cancellationToken);
+                // For JavaScript files, we don't want to report semantic errors.
+                // Instead, we'll report errors for using TypeScript-only constructs from within a
+                // JavaScript file when we get syntactic diagnostics for the file.
+                const checkDiagnostics = isSourceFileJavaScript(sourceFile) ? [] : typeChecker.getDiagnostics(sourceFile, cancellationToken);
                 const fileProcessingDiagnosticsInFile = fileProcessingDiagnostics.getDiagnostics(sourceFile.fileName);
                 const programDiagnosticsInFile = programDiagnostics.getDiagnostics(sourceFile.fileName);
 
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index f9ec3e9f268cc..bda350347c27c 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2024,6 +2024,9 @@ namespace ts {
         // as well as code diagnostics).
         /* @internal */ parseDiagnostics: Diagnostic[];
 
+        // Stores file level JavaScript diagnostics reported by the program
+        /* @internal */ parseJavaScriptDiagnostics?: Diagnostic[];
+
         // File level diagnostics reported by the binder.
         /* @internal */ bindDiagnostics: Diagnostic[];
 
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics1.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics1.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics1.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics1.ts
index a94318c84fde9..8c151742b752b 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics1.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics1.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// import a = b;
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'import ... =' can only be used in a .ts file.",
     "start": 0,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics10.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics10.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics10.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics10.ts
index 957357fc2c110..206c1a6e2cfc0 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics10.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics10.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// function F<T>() { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'type parameter declarations' can only be used in a .ts file.",
     "start": 11,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics11.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics11.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics11.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics11.ts
index d9c16fca65164..d9b1d35b5c65b 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics11.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics11.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// function F(): number { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'types' can only be used in a .ts file.",
     "start": 14,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics12.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics12.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics12.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics12.ts
index b4dcf07674323..cf244f7cfa25f 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics12.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics12.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// declare var v;
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'declare' can only be used in a .ts file.",
     "start": 0,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics13.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics13.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics13.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics13.ts
index a20bccc088763..aaf3289fcfe4c 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics13.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics13.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// var v: () => number;
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'types' can only be used in a .ts file.",
     "start": 7,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics14.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics14.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics14.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics14.ts
index 4f7673be38455..a41d88dd6757f 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics14.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics14.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// Foo<number>();
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'type arguments' can only be used in a .ts file.",
     "start": 4,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics15.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics15.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics15.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics15.ts
index f7cd4db362621..93430a9a004d6 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics15.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics15.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// function F(public p) { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'parameter modifiers' can only be used in a .ts file.",
     "start": 11,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics16.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics16.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics16.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics16.ts
index cd19bd580cc25..60e0684b10628 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics16.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics16.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// function F(p?) { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'?' can only be used in a .ts file.",
     "start": 12,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics17.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics17.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics17.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics17.ts
index 5a1ec6d92cf24..3a57917b2ac56 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics17.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics17.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// function F(a: number) { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'types' can only be used in a .ts file.",
     "start": 14,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics18.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics18.ts
similarity index 86%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics18.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics18.ts
index 707d1537fc5c7..d253cb636114d 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics18.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics18.ts
@@ -9,7 +9,7 @@
 ////}
 
 goTo.file("a.js");
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "\'public\' can only be used in a .ts file.",
     "start": 93,
@@ -25,7 +25,7 @@ verify.getSemanticDiagnostics(`[
 ////}
 
 goTo.file("b.js");
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'types' can only be used in a .ts file.",
     "start": 17,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics19.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics19.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics19.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics19.ts
index a7fbe3e0ecc64..7729a6ea47020 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics19.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics19.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// enum E { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'enum declarations' can only be used in a .ts file.",
     "start": 5,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics2.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics2.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics2.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics2.ts
index 9ab29b417984b..74e6a9ab089b6 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics2.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics2.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// export = b;
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'export=' can only be used in a .ts file.",
     "start": 0,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics21.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics21.ts
similarity index 100%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics21.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics21.ts
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics22.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics22.ts
similarity index 100%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics22.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics22.ts
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics23.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics23.ts
similarity index 100%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics23.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics23.ts
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics24.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics24.ts
similarity index 100%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics24.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics24.ts
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics3.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics3.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics3.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics3.ts
index 3aff51d881b09..3528f33332975 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics3.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics3.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// class C<T> { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'type parameter declarations' can only be used in a .ts file.",
     "start": 8,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics4.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics4.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics4.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics4.ts
index 99319b047e63c..3b849b08ae070 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics4.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics4.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// public class C { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'public' can only be used in a .ts file.",
     "start": 0,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics5.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics5.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics5.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics5.ts
index 18df3500bd975..985e3284025d8 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics5.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics5.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// class C implements D { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'implements clauses' can only be used in a .ts file.",
     "start": 8,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics6.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics6.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics6.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics6.ts
index e18f8f9be52c4..a0042a0529b7d 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics6.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics6.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// interface I { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'interface declarations' can only be used in a .ts file.",
     "start": 10,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics7.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics7.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics7.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics7.ts
index 32cad0e5a07bf..64216d1e36488 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics7.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics7.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// module M { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'module declarations' can only be used in a .ts file.",
     "start": 7,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics8.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics8.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics8.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics8.ts
index 562f42124aeae..296f4f7445e76 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics8.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics8.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// type a = b;
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'type aliases' can only be used in a .ts file.",
     "start": 5,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics9.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics9.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics9.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics9.ts
index 4c531b5255b92..f2c20a52ee971 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics9.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics9.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// public function F() { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'public' can only be used in a .ts file.",
     "start": 0,
diff --git a/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts b/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts
new file mode 100644
index 0000000000000..3439162e6916a
--- /dev/null
+++ b/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts
@@ -0,0 +1,40 @@
+/// <reference path="../fourslash.ts" />
+
+// @allowJs: true
+// @Filename: b.js
+//// var a = "a";
+//// var b: boolean = true;
+//// function foo(): string { }
+//// var var = "c";
+
+verify.getSyntacticDiagnostics(`[
+  {
+    "message": "Variable declaration expected.",
+    "start": 67,
+    "length": 3,
+    "category": "error",
+    "code": 1134
+  },
+  {
+    "message": "Variable declaration expected.",
+    "start": 71,
+    "length": 1,
+    "category": "error",
+    "code": 1134
+  },
+  {
+    "message": "Variable declaration expected.",
+    "start": 73,
+    "length": 3,
+    "category": "error",
+    "code": 1134
+  },
+  {
+    "message": "\'types\' can only be used in a .ts file.",
+    "start": 20,
+    "length": 7,
+    "category": "error",
+    "code": 8010
+  }
+]`);
+verify.getSemanticDiagnostics(`[]`);
\ No newline at end of file

From 07bb2582b6d40108873664aa7ddcc1a109530408 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Tue, 25 Oct 2016 12:38:59 -0700
Subject: [PATCH 087/224] Don't require `resolvedTsFileName` and
 `resolvedJsFileName`, just `resolvedFileName` and `extension`. Also, change
 search order to do all TS searching before searching for JS.

---
 src/compiler/moduleNameResolver.ts            | 283 ++++++++----------
 src/compiler/program.ts                       |  37 ++-
 src/compiler/types.ts                         |  22 +-
 src/compiler/utilities.ts                     |  54 ++--
 src/harness/unittests/moduleResolution.ts     | 164 ++--------
 .../unittests/reuseProgramStructure.ts        |   6 +-
 .../unittests/tsserverProjectSystem.ts        |  57 ++--
 src/server/lsHost.ts                          |   2 +-
 src/services/shims.ts                         |   2 +-
 ...portWithTrailingSlash_noResolve.trace.json |   2 +
 ...NodeModuleJsDepthDefaultsToZero.trace.json |  12 +-
 .../moduleResolutionWithExtensions.trace.json |   4 -
 ...tionWithExtensions_notSupported.errors.txt |   4 +-
 ...tionWithExtensions_notSupported.trace.json |  12 +-
 ...ionWithExtensions_notSupported2.trace.json |   7 +-
 ...solutionWithExtensions_preferTs.trace.json |   2 -
 ...thExtensions_withAmbientPresent.trace.json |  12 +-
 .../moduleResolutionWithSymlinks.trace.json   |  55 ++--
 ...gBasedModuleResolution3_classic.trace.json |   6 -
 ...pingBasedModuleResolution3_node.trace.json |  22 --
 ...gBasedModuleResolution4_classic.trace.json |   6 -
 ...pingBasedModuleResolution4_node.trace.json |  22 --
 ...gBasedModuleResolution5_classic.trace.json |  10 -
 ...pingBasedModuleResolution5_node.trace.json |  30 --
 ...gBasedModuleResolution6_classic.trace.json |   4 -
 ...pingBasedModuleResolution6_node.trace.json |  10 -
 ...gBasedModuleResolution7_classic.trace.json |  14 -
 ...pingBasedModuleResolution7_node.trace.json |  40 ---
 ...mMultipleNodeModulesDirectories.trace.json | 153 ++++++----
 ...romNodeModulesInParentDirectory.trace.json |  33 +-
 .../reference/typingsLookup4.trace.json       |  18 --
 .../reference/typingsLookupAmd.trace.json     |  36 ---
 32 files changed, 407 insertions(+), 734 deletions(-)

diff --git a/src/compiler/moduleNameResolver.ts b/src/compiler/moduleNameResolver.ts
index 33b1db24fcecb..1b0a579180270 100644
--- a/src/compiler/moduleNameResolver.ts
+++ b/src/compiler/moduleNameResolver.ts
@@ -16,51 +16,37 @@ namespace ts {
      * At least one of `ts` and `js` should be defined, or the whole thing should be `undefined`.
      */
     interface Resolved {
-        ts: string | undefined;
-        js: string | undefined;
+        path: string;
+        extension: Extension;
     }
 
     /**
-     * Given a resolution result which does not have a resolvedTsFileName, combine it with second attempt.
-     * This should be used in the following pattern:
-     *
-     * const attemptA = foo();
-     * return attemptA && attemptA.ts ? attemptA : combineAttempts(attemptA, bar());
-     *
-     * Meaning, we stop early if we found a typed result.
+     * Kinds of file that we are currently looking for.
+     * Typically there is one pass with Extensions.TypeScript, then a second pass with Extensions.JavaScript.
      */
-    function combineAttempts(firstAttempt: Resolved | undefined, secondAttempt: Resolved | undefined): Resolved | undefined {
-        Debug.assert(!(firstAttempt && firstAttempt.ts));
-        return firstAttempt && secondAttempt
-            ? { ts: secondAttempt.ts, js: firstAttempt.js }
-            : (firstAttempt || secondAttempt);
+    const enum Extensions {
+        TypeScript, /** '.ts', '.tsx', or '.d.ts' */
+        JavaScript, /** '.js' or '.jsx' */
+        DtsOnly /** Only '.d.ts' */
     }
 
-    /**
-     * Whether we are looking for all supported extensions or only `.d.ts` files.
-     * We look for tsx/jsx/js files even if the compiler settings do not allow them -- this will be a checker error.
-     */
-    enum Extensions { All, DtsOnly }
-
-    /** Used with `Extensions.DtsOnly` to use just the `ts` component, since `js` can't possibly be defined. */
-    function resolvedTsOnly(resolved: Resolved | undefined): string | undefined {
-        Debug.assert(!(resolved && resolved.js));
-        return resolved && resolved.ts;
+    /** Used with `Extensions.DtsOnly` to extract the path from TypeScript results. */
+    function resolvedTypeScriptOnly(resolved: Resolved | undefined): string | undefined {
+        if (!resolved) {
+            return undefined;
+        }
+        Debug.assert(extensionIsTypeScript(resolved.extension));
+        return resolved.path;
     }
 
     /** Create Resolved from a file with unknown extension. */
     function resolvedFromAnyFile(path: string): Resolved | undefined {
-        return fileExtensionIsAny(path, supportedTypeScriptExtensions) ? { ts: path, js: undefined } : { ts: undefined, js: path };
-    }
-
-    /* @internal */
-    export function resolvedModuleFromAnyFile(fileName: string, isExternalLibraryImport: boolean): ResolvedModule {
-        return resolvedModuleFromResolved(resolvedFromAnyFile(fileName), isExternalLibraryImport);
+        return { path, extension: extensionFromPath(path) };
     }
 
     /** Adds `isExernalLibraryImport` to a Resolved to get a ResolvedModule. */
-    function resolvedModuleFromResolved({ ts, js }: Resolved, isExternalLibraryImport: boolean): ResolvedModule {
-        return { resolvedFileName: ts || js, resolvedTsFileName: ts, resolvedJsFileName: js, isExternalLibraryImport };
+    function resolvedModuleFromResolved({ path, extension }: Resolved, isExternalLibraryImport: boolean): ResolvedModule {
+        return { resolvedFileName: path, extension, isExternalLibraryImport };
     }
 
     function createResolvedModuleWithFailedLookupLocations(resolved: Resolved | undefined, isExternalLibraryImport: boolean, failedLookupLocations: string[]): ResolvedModuleWithFailedLookupLocations {
@@ -74,13 +60,28 @@ namespace ts {
     interface ModuleResolutionState {
         host: ModuleResolutionHost;
         // We only use this subset of the compiler options.
-        compilerOptions: { rootDirs?: string[], baseUrl?: string, paths?: MapLike<string[]>; };
+        compilerOptions: { rootDirs?: string[], baseUrl?: string, paths?: MapLike<string[]> };
         traceEnabled: boolean;
     }
 
-    function tryReadTypesSection(packageJsonPath: string, baseDirectory: string, state: ModuleResolutionState): string {
+    function tryReadTypesSection(extensions: Extensions, packageJsonPath: string, baseDirectory: string, state: ModuleResolutionState): string {
         const jsonContent = readJson(packageJsonPath, state.host);
 
+        switch (extensions) {
+            case Extensions.DtsOnly:
+            case Extensions.TypeScript:
+                return tryReadFromField("typings") || tryReadFromField("types");
+
+            case Extensions.JavaScript:
+                if (typeof jsonContent.main === "string") {
+                    if (state.traceEnabled) {
+                        trace(state.host, Diagnostics.No_types_specified_in_package_json_so_returning_main_value_of_0, jsonContent.main);
+                    }
+                    return normalizePath(combinePaths(baseDirectory, jsonContent.main));
+                }
+                return undefined;
+        }
+
         function tryReadFromField(fieldName: string) {
             if (hasProperty(jsonContent, fieldName)) {
                 const typesFile = (<any>jsonContent)[fieldName];
@@ -98,20 +99,6 @@ namespace ts {
                 }
             }
         }
-
-        const typesFilePath = tryReadFromField("typings") || tryReadFromField("types");
-        if (typesFilePath) {
-            return typesFilePath;
-        }
-
-        // Use the main module for inferring types if no types package specified and the allowJs is set
-        if (typeof jsonContent.main === "string") {
-            if (state.traceEnabled) {
-                trace(state.host, Diagnostics.No_types_specified_in_package_json_so_returning_main_value_of_0, jsonContent.main);
-            }
-            return normalizePath(combinePaths(baseDirectory, jsonContent.main));
-        }
-        return undefined;
     }
 
     function readJson(path: string, host: ModuleResolutionHost): { typings?: string, types?: string, main?: string } {
@@ -214,7 +201,7 @@ namespace ts {
                 const candidate = combinePaths(typeRoot, typeReferenceDirectiveName);
                 const candidateDirectory = getDirectoryPath(candidate);
 
-                const resolved = resolvedTsOnly(
+                const resolved = resolvedTypeScriptOnly(
                     loadNodeModuleFromDirectory(Extensions.DtsOnly, candidate, failedLookupLocations,
                         !directoryProbablyExists(candidateDirectory, host), moduleResolutionState));
 
@@ -243,7 +230,7 @@ namespace ts {
             if (traceEnabled) {
                 trace(host, Diagnostics.Looking_up_in_node_modules_folder_initial_location_0, initialLocationForSecondaryLookup);
             }
-            resolvedFile = resolvedTsOnly(loadModuleFromNodeModules(Extensions.DtsOnly, typeReferenceDirectiveName, initialLocationForSecondaryLookup, failedLookupLocations, moduleResolutionState, /*checkOneLevel*/ false));
+            resolvedFile = resolvedTypeScriptOnly(loadModuleFromNodeModules(Extensions.DtsOnly, typeReferenceDirectiveName, initialLocationForSecondaryLookup, failedLookupLocations, moduleResolutionState, /*checkOneLevel*/ false));
             if (traceEnabled) {
                 if (resolvedFile) {
                     trace(host, Diagnostics.Type_reference_directive_0_was_successfully_resolved_to_1_primary_Colon_2, typeReferenceDirectiveName, resolvedFile, false);
@@ -351,7 +338,7 @@ namespace ts {
      * 'typings' entry or file 'index' with some supported extension
      * - Classic loader will only try to interpret '/a/b/c' as file.
      */
-    type ResolutionKindSpecificLoader = (candidate: string, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState) => Resolved | undefined;
+    type ResolutionKindSpecificLoader = (extensions: Extensions, candidate: string, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState) => Resolved | undefined;
 
     /**
      * Any module resolution kind can be augmented with optional settings: 'baseUrl', 'paths' and 'rootDirs' - they are used to
@@ -413,18 +400,18 @@ namespace ts {
      * be converted to a path relative to found rootDir entry './content/protocols/file2' (*). As a last step compiler will check all remaining
      * entries in 'rootDirs', use them to build absolute path out of (*) and try to resolve module from this location.
      */
-    function tryLoadModuleUsingOptionalResolutionSettings(moduleName: string, containingDirectory: string, loader: ResolutionKindSpecificLoader,
+    function tryLoadModuleUsingOptionalResolutionSettings(extensions: Extensions, moduleName: string, containingDirectory: string, loader: ResolutionKindSpecificLoader,
         failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
 
         if (moduleHasNonRelativeName(moduleName)) {
-            return tryLoadModuleUsingBaseUrl(moduleName, loader, failedLookupLocations, state);
+            return tryLoadModuleUsingBaseUrl(extensions, moduleName, loader, failedLookupLocations, state);
         }
         else {
-            return tryLoadModuleUsingRootDirs(moduleName, containingDirectory, loader, failedLookupLocations, state);
+            return tryLoadModuleUsingRootDirs(extensions, moduleName, containingDirectory, loader, failedLookupLocations, state);
         }
     }
 
-    function tryLoadModuleUsingRootDirs(moduleName: string, containingDirectory: string, loader: ResolutionKindSpecificLoader,
+    function tryLoadModuleUsingRootDirs(extensions: Extensions, moduleName: string, containingDirectory: string, loader: ResolutionKindSpecificLoader,
         failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
 
         if (!state.compilerOptions.rootDirs) {
@@ -470,7 +457,7 @@ namespace ts {
             if (state.traceEnabled) {
                 trace(state.host, Diagnostics.Loading_0_from_the_root_dir_1_candidate_location_2, suffix, matchedNormalizedPrefix, candidate);
             }
-            const resolvedFileName = loader(candidate, failedLookupLocations, !directoryProbablyExists(containingDirectory, state.host), state);
+            const resolvedFileName = loader(extensions, candidate, failedLookupLocations, !directoryProbablyExists(containingDirectory, state.host), state);
             if (resolvedFileName) {
                 return resolvedFileName;
             }
@@ -489,7 +476,7 @@ namespace ts {
                     trace(state.host, Diagnostics.Loading_0_from_the_root_dir_1_candidate_location_2, suffix, rootDir, candidate);
                 }
                 const baseDirectory = getDirectoryPath(candidate);
-                const resolvedFileName = loader(candidate, failedLookupLocations, !directoryProbablyExists(baseDirectory, state.host), state);
+                const resolvedFileName = loader(extensions, candidate, failedLookupLocations, !directoryProbablyExists(baseDirectory, state.host), state);
                 if (resolvedFileName) {
                     return resolvedFileName;
                 }
@@ -501,7 +488,7 @@ namespace ts {
         return undefined;
     }
 
-    function tryLoadModuleUsingBaseUrl(moduleName: string, loader: ResolutionKindSpecificLoader, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
+    function tryLoadModuleUsingBaseUrl(extensions: Extensions, moduleName: string, loader: ResolutionKindSpecificLoader, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
         if (!state.compilerOptions.baseUrl) {
             return undefined;
         }
@@ -530,7 +517,7 @@ namespace ts {
                 if (state.traceEnabled) {
                     trace(state.host, Diagnostics.Trying_substitution_0_candidate_module_location_Colon_1, subst, path);
                 }
-                const resolved = loader(candidate, failedLookupLocations, !directoryProbablyExists(getDirectoryPath(candidate), state.host), state);
+                const resolved = loader(extensions, candidate, failedLookupLocations, !directoryProbablyExists(getDirectoryPath(candidate), state.host), state);
                 if (resolved) {
                     return resolved;
                 }
@@ -544,7 +531,7 @@ namespace ts {
                 trace(state.host, Diagnostics.Resolving_module_name_0_relative_to_base_url_1_2, moduleName, state.compilerOptions.baseUrl, candidate);
             }
 
-            return loader(candidate, failedLookupLocations, !directoryProbablyExists(getDirectoryPath(candidate), state.host), state);
+            return loader(extensions, candidate, failedLookupLocations, !directoryProbablyExists(getDirectoryPath(candidate), state.host), state);
         }
     }
 
@@ -554,48 +541,54 @@ namespace ts {
 
         const failedLookupLocations: string[] = [];
         const state: ModuleResolutionState = { compilerOptions, host, traceEnabled };
-        let resolved = tryLoadModuleUsingOptionalResolutionSettings(moduleName, containingDirectory, nodeLoadModuleByRelativeName, failedLookupLocations, state);
 
-        let isExternalLibraryImport = false;
-        if (!resolved) {
+        const result = tryResolve(Extensions.TypeScript) || tryResolve(Extensions.JavaScript);
+        if (result) {
+            const { resolved, isExternalLibraryImport } = result;
+            return createResolvedModuleWithFailedLookupLocations(resolved && resolvedWithRealpath(resolved, host, traceEnabled), isExternalLibraryImport, failedLookupLocations);
+        }
+        return { resolvedModule: undefined, failedLookupLocations };
+
+        function tryResolve(extensions: Extensions): { resolved: Resolved, isExternalLibraryImport: boolean } | undefined {
+            const resolved = tryLoadModuleUsingOptionalResolutionSettings(extensions, moduleName, containingDirectory, nodeLoadModuleByRelativeName, failedLookupLocations, state);
+            if (resolved) {
+                return { resolved, isExternalLibraryImport: false };
+            }
+
             if (moduleHasNonRelativeName(moduleName)) {
                 if (traceEnabled) {
                     trace(host, Diagnostics.Loading_module_0_from_node_modules_folder, moduleName);
                 }
-                resolved = loadModuleFromNodeModules(Extensions.All, moduleName, containingDirectory, failedLookupLocations, state, /*checkOneLevel*/ false);
-                isExternalLibraryImport = resolved !== undefined;
+                const resolved = loadModuleFromNodeModules(extensions, moduleName, containingDirectory, failedLookupLocations, state, /*checkOneLevel*/ false);
+                return resolved && { resolved, isExternalLibraryImport: true };
             }
             else {
                 const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
-                resolved = nodeLoadModuleByRelativeName(candidate, failedLookupLocations, /*onlyRecordFailures*/ false, state);
+                const resolved = nodeLoadModuleByRelativeName(extensions, candidate, failedLookupLocations, /*onlyRecordFailures*/ false, state);
+                return resolved && { resolved, isExternalLibraryImport: false };
             }
         }
-
-        return createResolvedModuleWithFailedLookupLocations(resolved && resolvedWithRealpath(resolved, host, traceEnabled), isExternalLibraryImport, failedLookupLocations);
     }
 
     function resolvedWithRealpath(resolved: Resolved, host: ModuleResolutionHost, traceEnabled: boolean): Resolved {
-        return host.realpath ? { ts: resolved.ts && realpath(resolved.ts), js: resolved.js && realpath(resolved.js) } : resolved;
+        if (!host.realpath) {
+            return resolved;
+        }
 
-        function realpath(path: string): string {
-            const real = normalizePath(host.realpath(path));
-            if (traceEnabled) {
-                trace(host, Diagnostics.Resolving_real_path_for_0_result_1, path, real);
-            }
-            return real;
+        const real = normalizePath(host.realpath(resolved.path));
+        if (traceEnabled) {
+            trace(host, Diagnostics.Resolving_real_path_for_0_result_1, resolved.path, real);
         }
+        return { path: real, extension: resolved.extension };
     }
 
-    function nodeLoadModuleByRelativeName(candidate: string, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
+    function nodeLoadModuleByRelativeName(extensions: Extensions, candidate: string, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
         if (state.traceEnabled) {
             trace(state.host, Diagnostics.Loading_module_as_file_Slash_folder_candidate_module_location_0, candidate);
         }
 
-        const resolvedFromFile = !pathEndsWithDirectorySeparator(candidate) && loadModuleFromFile(Extensions.All, candidate, failedLookupLocations, onlyRecordFailures, state);
-        return resolvedFromFile && resolvedFromFile.ts
-            ? resolvedFromFile
-            : combineAttempts(resolvedFromFile,
-                loadNodeModuleFromDirectory(Extensions.All, candidate, failedLookupLocations, onlyRecordFailures, state));
+        const resolvedFromFile = !pathEndsWithDirectorySeparator(candidate) && loadModuleFromFile(extensions, candidate, failedLookupLocations, onlyRecordFailures, state);
+        return resolvedFromFile || loadNodeModuleFromDirectory(extensions, candidate, failedLookupLocations, onlyRecordFailures, state);
     }
 
     /* @internal */
@@ -604,10 +597,6 @@ namespace ts {
         return !host.directoryExists || host.directoryExists(directoryName);
     }
 
-    function loadModuleFromFileAnyExtension(candidate: string, failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
-        return loadModuleFromFile(Extensions.All, candidate, failedLookupLocations, onlyRecordFailures, state);
-    }
-
     /**
      * @param {boolean} onlyRecordFailures - if true then function won't try to actually load files but instead record all attempts as failures. This flag is necessary
      * in cases when we know upfront that all load attempts will fail (because containing folder does not exists) however we still need to record all failed lookup locations.
@@ -627,7 +616,7 @@ namespace ts {
                 const extension = candidate.substring(extensionless.length);
                 trace(state.host, Diagnostics.File_name_0_has_a_1_extension_stripping_it, candidate, extension);
             }
-            return tryAddingExtensions(extensionless, Extensions.All, failedLookupLocations, onlyRecordFailures, state);
+            return tryAddingExtensions(extensionless, extensions, failedLookupLocations, onlyRecordFailures, state);
         }
     }
 
@@ -642,23 +631,17 @@ namespace ts {
         }
 
         switch (extensions) {
-            case Extensions.DtsOnly: {
-                const dts = tryExtension(".d.ts");
-                return dts && { ts: dts, js: undefined };
-            }
-            case Extensions.All: {
-                const ts = forEach(supportedTypeScriptExtensions, tryExtension);
-                if (ts) {
-                    return { ts, js: undefined };
-                }
-
-                const js = forEach(supportedJavascriptExtensions, tryExtension);
-                return js && { ts: undefined, js };
-            }
+            case Extensions.DtsOnly:
+                return tryExtension(".d.ts", Extension.Dts);
+            case Extensions.TypeScript:
+                return tryExtension(".ts", Extension.Ts) || tryExtension(".tsx", Extension.Tsx) || tryExtension(".d.ts", Extension.Dts);
+            case Extensions.JavaScript:
+                return tryExtension(".js", Extension.Js) || tryExtension(".jsx", Extension.Jsx);
         }
 
-        function tryExtension(ext: string): string | undefined {
-            return tryFile(candidate + ext, failedLookupLocations, onlyRecordFailures, state);
+        function tryExtension(ext: string, extension: Extension): Resolved | undefined {
+            const path = tryFile(candidate + ext, failedLookupLocations, onlyRecordFailures, state);
+            return path && { path, extension };
         }
     }
 
@@ -683,23 +666,22 @@ namespace ts {
         const packageJsonPath = pathToPackageJson(candidate);
         const directoryExists = !onlyRecordFailures && directoryProbablyExists(candidate, state.host);
 
-        let fromPackageJson: Resolved | undefined;
-
         if (directoryExists && state.host.fileExists(packageJsonPath)) {
             if (state.traceEnabled) {
                 trace(state.host, Diagnostics.Found_package_json_at_0, packageJsonPath);
             }
-            const typesFile = tryReadTypesSection(packageJsonPath, candidate, state);
+            const typesFile = tryReadTypesSection(extensions, packageJsonPath, candidate, state);
             if (typesFile) {
                 const onlyRecordFailures = !directoryProbablyExists(getDirectoryPath(typesFile), state.host);
                 // A package.json "typings" may specify an exact filename, or may choose to omit an extension.
                 const fromFile = tryFile(typesFile, failedLookupLocation, onlyRecordFailures, state);
                 if (fromFile) {
+                    // Note: this would allow a package.json to specify a ".js" file as typings. Maybe that should be forbidden.
                     return resolvedFromAnyFile(fromFile);
                 }
-                fromPackageJson = tryAddingExtensions(typesFile, Extensions.All, failedLookupLocation, onlyRecordFailures, state);
-                if (fromPackageJson && fromPackageJson.ts) {
-                    return fromPackageJson;
+                const x = tryAddingExtensions(typesFile, Extensions.TypeScript, failedLookupLocation, onlyRecordFailures, state);
+                if (x) {
+                    return x;
                 }
             }
             else {
@@ -716,7 +698,7 @@ namespace ts {
             failedLookupLocation.push(packageJsonPath);
         }
 
-        return combineAttempts(fromPackageJson, loadModuleFromFile(extensions, combinePaths(candidate, "index"), failedLookupLocation, !directoryExists, state));
+        return loadModuleFromFile(extensions, combinePaths(candidate, "index"), failedLookupLocation, !directoryExists, state);
     }
 
     function pathToPackageJson(directory: string): string {
@@ -728,54 +710,39 @@ namespace ts {
         const nodeModulesFolderExists = directoryProbablyExists(nodeModulesFolder, state.host);
         const candidate = normalizePath(combinePaths(nodeModulesFolder, moduleName));
 
-        let result = loadModuleFromFile(extensions, candidate, failedLookupLocations, !nodeModulesFolderExists, state);
-        if (result) {
-            return result;
-        }
-        result = loadNodeModuleFromDirectory(extensions, candidate, failedLookupLocations, !nodeModulesFolderExists, state);
-        if (result) {
-            return result;
-        }
+        return loadModuleFromFile(extensions, candidate, failedLookupLocations, !nodeModulesFolderExists, state) ||
+            loadNodeModuleFromDirectory(extensions, candidate, failedLookupLocations, !nodeModulesFolderExists, state);
     }
 
     function loadModuleFromNodeModules(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState, checkOneLevel: boolean): Resolved | undefined {
         return loadModuleFromNodeModulesWorker(extensions, moduleName, directory, failedLookupLocations, state, checkOneLevel, /*typesOnly*/ false);
     }
     function loadModuleFromNodeModulesAtTypes(moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
-        return loadModuleFromNodeModulesWorker(Extensions.All, moduleName, directory, failedLookupLocations, state, /*checkOneLevel*/ false, /*typesOnly*/ true);
+        return loadModuleFromNodeModulesWorker(Extensions.TypeScript, moduleName, directory, failedLookupLocations, state, /*checkOneLevel*/ false, /*typesOnly*/ true);
     }
 
     function loadModuleFromNodeModulesWorker(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState, checkOneLevel: boolean, typesOnly: boolean): Resolved | undefined {
         directory = normalizeSlashes(directory);
         while (true) {
-            const baseName = getBaseFileName(directory);
-            if (baseName !== "node_modules") {
-                let packageResult: Resolved | undefined;
-                if (!typesOnly) {
-                    // Try to load source from the package
-                    packageResult = loadModuleFromNodeModulesFolder(extensions, moduleName, directory, failedLookupLocations, state);
-                    if (packageResult && packageResult.ts) {
-                        // Always prefer a TypeScript (.ts, .tsx, .d.ts) file shipped with the package
-                        return packageResult;
-                    }
-                }
-
-                // Else prefer a types package over non-TypeScript results (e.g. JavaScript files)
-                const typesResult = loadModuleFromNodeModulesFolder(extensions, combinePaths("@types", moduleName), directory, failedLookupLocations, state);
-                if (typesResult || packageResult) {
-                    return combineAttempts(packageResult, typesResult);
+            if (getBaseFileName(directory) !== "node_modules") {
+                const resolved = tryInDirectory();
+                if (resolved) {
+                    return resolved;
                 }
-                // TODO (anhans): We should remember JS results and use them for untyped results.
             }
 
             const parentPath = getDirectoryPath(directory);
             if (parentPath === directory || checkOneLevel) {
-                break;
+                return undefined;
             }
 
             directory = parentPath;
         }
-        return undefined;
+
+        function tryInDirectory(): Resolved | undefined {
+            const packageResult = typesOnly ? undefined : loadModuleFromNodeModulesFolder(extensions, moduleName, directory, failedLookupLocations, state);
+            return packageResult || loadModuleFromNodeModulesFolder(extensions, combinePaths("@types", moduleName), directory, failedLookupLocations, state);
+        }
     }
 
     export function classicNameResolver(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost): ResolvedModuleWithFailedLookupLocations {
@@ -784,30 +751,37 @@ namespace ts {
         const failedLookupLocations: string[] = [];
         const containingDirectory = getDirectoryPath(containingFile);
 
-        const resolvedUsingSettings = tryLoadModuleUsingOptionalResolutionSettings(moduleName, containingDirectory, loadModuleFromFileAnyExtension, failedLookupLocations, state);
-        if (resolvedUsingSettings) {
-            return createResolvedModuleWithFailedLookupLocations(resolvedUsingSettings, /*isExternalLibraryImport*/ false, failedLookupLocations);
-        }
+        const resolved = tryResolve(Extensions.TypeScript) || tryResolve(Extensions.JavaScript);
+        return createResolvedModuleWithFailedLookupLocations(resolved, /*isExternalLibraryImport*/ false, failedLookupLocations);
 
-        let resolved: Resolved | undefined;
-        if (moduleHasNonRelativeName(moduleName)) {
-            resolved = loadModuleFromAncestorDirectories(moduleName, containingDirectory, failedLookupLocations, state) ||
-                // If we didn't find the file normally, look it up in @types.
-                loadModuleFromNodeModulesAtTypes(moduleName, containingDirectory, failedLookupLocations, state);
-        }
-        else {
-            const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
-            resolved = loadModuleFromFileAnyExtension(candidate, failedLookupLocations, /*onlyRecordFailures*/ false, state);
-        }
+        function tryResolve(extensions: Extensions): Resolved | undefined {
+            const resolvedUsingSettings = tryLoadModuleUsingOptionalResolutionSettings(extensions, moduleName, containingDirectory, loadModuleFromFile, failedLookupLocations, state);
+            if (resolvedUsingSettings) {
+                return resolvedUsingSettings;
+            }
 
-        return createResolvedModuleWithFailedLookupLocations(resolved, /*isExternalLibraryImport*/ false, failedLookupLocations);
+            if (moduleHasNonRelativeName(moduleName)) {
+                const resolved = loadModuleFromAncestorDirectories(extensions, moduleName, containingDirectory, failedLookupLocations, state);
+                if (resolved) {
+                    return resolved;
+                }
+                if (extensions === Extensions.TypeScript) {
+                    // If we didn't find the file normally, look it up in @types.
+                    return loadModuleFromNodeModulesAtTypes(moduleName, containingDirectory, failedLookupLocations, state);
+                }
+            }
+            else {
+                const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
+                return loadModuleFromFile(extensions, candidate, failedLookupLocations, /*onlyRecordFailures*/ false, state);
+            }
+        }
     }
 
     /** Climb up parent directories looking for a module. */
-    function loadModuleFromAncestorDirectories(moduleName: string, containingDirectory: string, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
+    function loadModuleFromAncestorDirectories(extensions: Extensions, moduleName: string, containingDirectory: string, failedLookupLocations: string[], state: ModuleResolutionState): Resolved | undefined {
         while (true) {
             const searchName = normalizePath(combinePaths(containingDirectory, moduleName));
-            const referencedSourceFile = loadModuleFromFileAnyExtension(searchName, failedLookupLocations, /*onlyRecordFailures*/ false, state);
+            const referencedSourceFile = loadModuleFromFile(extensions, searchName, failedLookupLocations, /*onlyRecordFailures*/ false, state);
             if (referencedSourceFile) {
                 return referencedSourceFile;
             }
@@ -831,7 +805,8 @@ namespace ts {
         }
         const state: ModuleResolutionState = { compilerOptions, host, traceEnabled };
         const failedLookupLocations: string[] = [];
-        const resolved = loadModuleFromNodeModules(Extensions.All, moduleName, globalCache, failedLookupLocations, state, /*checkOneLevel*/ true);
+        const resolved = loadModuleFromNodeModules(Extensions.TypeScript, moduleName, globalCache, failedLookupLocations, state, /*checkOneLevel*/ true) ||
+            loadModuleFromNodeModules(Extensions.JavaScript, moduleName, globalCache, failedLookupLocations, state, /*checkOneLevel*/ true);
         return createResolvedModuleWithFailedLookupLocations(resolved, /*isExternalLibraryImport*/ true, failedLookupLocations);
     }
 }
\ No newline at end of file
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index a0cfe222c09d2..b2f8ab98f810b 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -331,7 +331,15 @@ namespace ts {
 
         let resolveModuleNamesWorker: (moduleNames: string[], containingFile: string) => ResolvedModule[];
         if (host.resolveModuleNames) {
-            resolveModuleNamesWorker = (moduleNames, containingFile) => host.resolveModuleNames(moduleNames, containingFile).map(convertResolvedModuleFromHost);
+            resolveModuleNamesWorker = (moduleNames, containingFile) => host.resolveModuleNames(moduleNames, containingFile).map(resolved => {
+                // An older host may have omitted extension, in which case we should infer it from the file extension of resolvedFileName.
+                if (!resolved || resolved.extension) {
+                    return resolved;
+                }
+                resolved = clone(resolved);
+                resolved.extension = extensionFromPath(resolved.resolvedFileName);
+                return resolved;
+            });
         }
         else {
             const loader = (moduleName: string, containingFile: string) => resolveModuleName(moduleName, containingFile, options, host).resolvedModule;
@@ -1317,7 +1325,7 @@ namespace ts {
                     }
 
                     const isFromNodeModulesSearch = resolution.isExternalLibraryImport;
-                    const isJsFileFromNodeModules = isFromNodeModulesSearch && !resolution.resolvedTsFileName;
+                    const isJsFileFromNodeModules = isFromNodeModulesSearch && !extensionIsTypeScript(resolution.extension);
                     const resolvedFileName = resolution.resolvedFileName;
 
                     if (isFromNodeModulesSearch) {
@@ -1581,20 +1589,19 @@ namespace ts {
      * Returns a DiagnosticMessage if we can't use a resolved module due to its extension.
      * The DiagnosticMessage's parameters are the imported module name, and the filename it resolved to.
      */
-    export function getResolutionDiagnostic(options: CompilerOptions, { resolvedTsFileName: ts, resolvedJsFileName: js }: ResolvedModule): DiagnosticMessage | undefined {
-        if (ts) {
-            return !options.jsx && fileExtensionIs(ts, ".tsx") ? Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set : undefined;
-        }
-        else {
-            if (!options.allowJs) {
-                return Diagnostics.Module_0_was_resolved_to_1_but_allowJs_is_not_set;
-            }
-            else if (!options.jsx && fileExtensionIs(js!, ".jsx")) {
-                return Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set;
-            }
-            else {
+    export function getResolutionDiagnostic(options: CompilerOptions, { extension }: ResolvedModule): DiagnosticMessage | undefined {
+        switch (extension) {
+            case Extension.Ts:
+            case Extension.Dts:
+                // These are always allowed.
                 return undefined;
-            }
+
+            case Extension.Tsx:
+            case Extension.Jsx:
+                return options.jsx ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set;
+
+            case Extension.Js:
+                return options.allowJs ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_allowJs_is_not_set;
         }
     }
 }
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 3e43d3ddf1052..88e42c0388a63 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -3296,22 +3296,26 @@ namespace ts {
      * else resolution should just return `undefined` instead of a ResolvedModule.
      */
     export interface ResolvedModule {
-        /**
-         * This should always be set to `resolvedTsFileName || resolvedJsFileName`.
-         * Present for backwards compatibility.
-         */
+        /** Path of the file the module was resolved to. */
         resolvedFileName: string;
-        /** TypeScript (.d.ts, .ts, .tsx) file that the module was resolved to. This will be preferred over a JS file. */
-        resolvedTsFileName?: string;
-        /** JavaScript (or .jsx) file that the module was resolved to. This should be returned even if '--allowJs' (or '--jsx') is disabled. */
-        resolvedJsFileName?: string;
+        /** Extension of resolvedFileName. This must match what's at the end of resolvedFileName. */
+        extension: Extension;
         /**
          * Denotes if 'resolvedFileName' is isExternalLibraryImport and thus should be a proper external module:
          * - be a .d.ts file
          * - use top level imports\exports
          * - don't use tripleslash references
          */
-        isExternalLibraryImport: boolean;
+        isExternalLibraryImport?: boolean;
+    }
+
+    export enum Extension {
+        Ts,
+        Tsx,
+        Dts,
+        Js,
+        Jsx,
+        LastTypeScriptExtension = Dts
     }
 
     export interface ResolvedModuleWithFailedLookupLocations {
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index cd75ca6d4d488..8398aa1aa1962 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -118,30 +118,6 @@ namespace ts {
         sourceFile.resolvedModules[moduleNameText] = resolvedModule;
     }
 
-    /** An older host may have omitted resolvedTsFileName and resolvedJsFileName, in which case we should infer them from the file extension of resolvedFileName. */
-    export function convertResolvedModuleFromHost(resolved: ResolvedModule | undefined): ResolvedModule | undefined {
-        if (resolved === undefined) {
-            return undefined;
-        }
-        // At least one of `resolevdTsFileName` or `resolvedJsFileName` should be defined.
-        else if (resolved.resolvedTsFileName || resolved.resolvedJsFileName) {
-            const { resolvedFileName, resolvedTsFileName, resolvedJsFileName } = resolved as ResolvedModule;
-            Debug.assert(resolvedFileName === (resolvedTsFileName || resolvedJsFileName));
-            return resolved;
-        }
-        else {
-            // For backwards compatibility, if both `resolvedTsFileName` and `resolvedJsFileName` are undefined, we infer one of them to define.
-            const { resolvedFileName, isExternalLibraryImport } = resolved;
-            if (fileExtensionIsAny(resolvedFileName, supportedTypeScriptExtensions)) {
-                return { resolvedFileName, resolvedTsFileName: resolvedFileName, resolvedJsFileName: undefined, isExternalLibraryImport };
-            }
-            else {
-                Debug.assert(fileExtensionIsAny(resolvedFileName, supportedJavascriptExtensions));
-                return { resolvedFileName, resolvedTsFileName: undefined, resolvedJsFileName: resolvedFileName, isExternalLibraryImport };
-            }
-        }
-    }
-
     export function setResolvedTypeReferenceDirective(sourceFile: SourceFile, typeReferenceDirectiveName: string, resolvedTypeReferenceDirective: ResolvedTypeReferenceDirective): void {
         if (!sourceFile.resolvedTypeReferenceDirectiveNames) {
             sourceFile.resolvedTypeReferenceDirectiveNames = createMap<ResolvedTypeReferenceDirective>();
@@ -157,9 +133,39 @@ namespace ts {
      */
     export function moduleResolutionIsEqualTo(oldResolution: ResolvedModule, newResolution: ResolvedModule): boolean {
         return oldResolution.isExternalLibraryImport === newResolution.isExternalLibraryImport &&
+            oldResolution.extension === newResolution.extension &&
             oldResolution.resolvedFileName === newResolution.resolvedFileName;
     }
 
+    /** True if an extension is one of the supported TypeScript extensions. */
+    export function extensionIsTypeScript(ext: Extension): boolean {
+        return ext <= Extension.LastTypeScriptExtension;
+    }
+
+    /**
+     * Gets the extension from a path.
+     * Path must have a valid extension.
+     */
+    export function extensionFromPath(path: string): Extension {
+        if (fileExtensionIs(path, ".d.ts")) {
+            return Extension.Dts;
+        }
+        if (fileExtensionIs(path, ".ts")) {
+            return Extension.Ts;
+        }
+        if (fileExtensionIs(path, ".tsx")) {
+            return Extension.Tsx;
+        }
+        if (fileExtensionIs(path, ".js")) {
+            return Extension.Js;
+        }
+        if (fileExtensionIs(path, ".jsx")) {
+            return Extension.Jsx;
+        }
+        Debug.fail(`File ${path} has unknown extension.`);
+        return Extension.Js;
+    }
+
     /* @internal */
     export function typeDirectiveIsEqualTo(oldResolution: ResolvedTypeReferenceDirective, newResolution: ResolvedTypeReferenceDirective): boolean {
         return oldResolution.resolvedFileName === newResolution.resolvedFileName && oldResolution.primary === newResolution.primary;
diff --git a/src/harness/unittests/moduleResolution.ts b/src/harness/unittests/moduleResolution.ts
index 21e7f6f990d4c..a713d93cfe072 100644
--- a/src/harness/unittests/moduleResolution.ts
+++ b/src/harness/unittests/moduleResolution.ts
@@ -4,8 +4,8 @@ namespace ts {
     export function checkResolvedModule(expected: ResolvedModule, actual: ResolvedModule): boolean {
         if (!expected === !actual) {
             if (expected) {
-                assert.isTrue(expected.resolvedTsFileName === actual.resolvedTsFileName, `'resolvedTsFileName': expected '${expected.resolvedTsFileName}' to be equal to '${actual.resolvedTsFileName}'`);
-                assert.isTrue(expected.resolvedJsFileName === actual.resolvedJsFileName, `'resolvedTsFileName': expected '${expected.resolvedJsFileName}' to be equal to '${actual.resolvedJsFileName}'`);
+                assert.isTrue(expected.resolvedFileName === actual.resolvedFileName, `'resolvedFileName': expected '${expected.resolvedFileName}' to be equal to '${actual.resolvedFileName}'`);
+                assert.isTrue(expected.extension === actual.extension, `'ext': expected '${Extension[expected.extension]}' to be equal to '${Extension[actual.extension]}'`);
                 assert.isTrue(expected.isExternalLibraryImport === actual.isExternalLibraryImport, `'isExternalLibraryImport': expected '${expected.isExternalLibraryImport}' to be equal to '${actual.isExternalLibraryImport}'`);
             }
             return true;
@@ -19,8 +19,8 @@ namespace ts {
         assert.deepEqual(actual.failedLookupLocations, expectedFailedLookupLocations);
     }
 
-    export function createTsResolvedModule(resolvedTsFileName: string, isExternalLibraryImport = false): ResolvedModule {
-        return { resolvedFileName: resolvedTsFileName, resolvedTsFileName, resolvedJsFileName: undefined, isExternalLibraryImport };
+    export function createResolvedModule(resolvedFileName: string, isExternalLibraryImport = false): ResolvedModule {
+        return { resolvedFileName, extension: extensionFromPath(resolvedFileName), isExternalLibraryImport };
     }
 
     interface File {
@@ -75,7 +75,7 @@ namespace ts {
                 const containingFile = { name: containingFileName };
                 const moduleFile = { name: moduleFileNameNoExt + ext };
                 const resolution = nodeModuleNameResolver(moduleName, containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, moduleFile));
-                checkResolvedModule(resolution.resolvedModule, createTsResolvedModule(moduleFile.name));
+                checkResolvedModule(resolution.resolvedModule, createResolvedModule(moduleFile.name));
 
                 const failedLookupLocations: string[] = [];
                 const dir = getDirectoryPath(containingFileName);
@@ -118,9 +118,9 @@ namespace ts {
                 const packageJson = { name: packageJsonFileName, content: JSON.stringify({ "typings": fieldRef }) };
                 const moduleFile = { name: moduleFileName };
                 const resolution = nodeModuleNameResolver(moduleName, containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, packageJson, moduleFile));
-                checkResolvedModule(resolution.resolvedModule, createTsResolvedModule(moduleFile.name));
+                checkResolvedModule(resolution.resolvedModule, createResolvedModule(moduleFile.name));
                 // expect three failed lookup location - attempt to load module as file with all supported extensions
-                assert.equal(resolution.failedLookupLocations.length, allSupportedExtensions.length);
+                assert.equal(resolution.failedLookupLocations.length, supportedTypeScriptExtensions.length);
             }
         }
 
@@ -145,7 +145,7 @@ namespace ts {
 
                 const resolution = nodeModuleNameResolver("b", containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, packageJson, moduleFile, indexFile));
 
-                checkResolvedModule(resolution.resolvedModule, createTsResolvedModule(indexPath, /*isExternalLibraryImport*/true));
+                checkResolvedModule(resolution.resolvedModule, createResolvedModule(indexPath, /*isExternalLibraryImport*/true));
             }
         }
 
@@ -167,18 +167,10 @@ namespace ts {
                 const packageJson = { name: "/a/b/foo/package.json", content: JSON.stringify({ main: "/c/d" }) };
                 const indexFile = { name: "/a/b/foo/index.d.ts" };
                 const resolution = nodeModuleNameResolver("./foo", containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, packageJson, indexFile));
-                checkResolvedModuleWithFailedLookupLocations(resolution, createTsResolvedModule(indexFile.name), [
+                checkResolvedModuleWithFailedLookupLocations(resolution, createResolvedModule(indexFile.name), [
                     "/a/b/foo.ts",
                     "/a/b/foo.tsx",
                     "/a/b/foo.d.ts",
-                    "/a/b/foo.js",
-                    "/a/b/foo.jsx",
-                    "/c/d",
-                    "/c/d.ts",
-                    "/c/d.tsx",
-                    "/c/d.d.ts",
-                    "/c/d.js",
-                    "/c/d.jsx",
                     "/a/b/foo/index.ts",
                     "/a/b/foo/index.tsx",
                 ]);
@@ -195,58 +187,42 @@ namespace ts {
                 const containingFile = { name: "/a/b/c/d/e.ts" };
                 const moduleFile = { name: "/a/b/node_modules/foo.ts" };
                 const resolution = nodeModuleNameResolver("foo", containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, moduleFile));
-                checkResolvedModuleWithFailedLookupLocations(resolution, createTsResolvedModule(moduleFile.name, /*isExternalLibraryImport*/ true), [
+                checkResolvedModuleWithFailedLookupLocations(resolution, createResolvedModule(moduleFile.name, /*isExternalLibraryImport*/ true), [
                     "/a/b/c/d/node_modules/foo.ts",
                     "/a/b/c/d/node_modules/foo.tsx",
                     "/a/b/c/d/node_modules/foo.d.ts",
-                    "/a/b/c/d/node_modules/foo.js",
-                    "/a/b/c/d/node_modules/foo.jsx",
                     "/a/b/c/d/node_modules/foo/package.json",
 
                     "/a/b/c/d/node_modules/foo/index.ts",
                     "/a/b/c/d/node_modules/foo/index.tsx",
                     "/a/b/c/d/node_modules/foo/index.d.ts",
-                    "/a/b/c/d/node_modules/foo/index.js",
-                    "/a/b/c/d/node_modules/foo/index.jsx",
 
                     "/a/b/c/d/node_modules/@types/foo.ts",
                     "/a/b/c/d/node_modules/@types/foo.tsx",
                     "/a/b/c/d/node_modules/@types/foo.d.ts",
-                    "/a/b/c/d/node_modules/@types/foo.js",
-                    "/a/b/c/d/node_modules/@types/foo.jsx",
                     "/a/b/c/d/node_modules/@types/foo/package.json",
 
                     "/a/b/c/d/node_modules/@types/foo/index.ts",
                     "/a/b/c/d/node_modules/@types/foo/index.tsx",
                     "/a/b/c/d/node_modules/@types/foo/index.d.ts",
-                    "/a/b/c/d/node_modules/@types/foo/index.js",
-                    "/a/b/c/d/node_modules/@types/foo/index.jsx",
 
                     "/a/b/c/node_modules/foo.ts",
                     "/a/b/c/node_modules/foo.tsx",
                     "/a/b/c/node_modules/foo.d.ts",
-                    "/a/b/c/node_modules/foo.js",
-                    "/a/b/c/node_modules/foo.jsx",
                     "/a/b/c/node_modules/foo/package.json",
 
                     "/a/b/c/node_modules/foo/index.ts",
                     "/a/b/c/node_modules/foo/index.tsx",
                     "/a/b/c/node_modules/foo/index.d.ts",
-                    "/a/b/c/node_modules/foo/index.js",
-                    "/a/b/c/node_modules/foo/index.jsx",
 
                     "/a/b/c/node_modules/@types/foo.ts",
                     "/a/b/c/node_modules/@types/foo.tsx",
                     "/a/b/c/node_modules/@types/foo.d.ts",
-                    "/a/b/c/node_modules/@types/foo.js",
-                    "/a/b/c/node_modules/@types/foo.jsx",
                     "/a/b/c/node_modules/@types/foo/package.json",
 
                     "/a/b/c/node_modules/@types/foo/index.ts",
                     "/a/b/c/node_modules/@types/foo/index.tsx",
                     "/a/b/c/node_modules/@types/foo/index.d.ts",
-                    "/a/b/c/node_modules/@types/foo/index.js",
-                    "/a/b/c/node_modules/@types/foo/index.jsx",
                 ]);
             }
         });
@@ -259,7 +235,7 @@ namespace ts {
                 const containingFile = { name: "/a/b/c/d/e.ts" };
                 const moduleFile = { name: "/a/b/node_modules/foo.d.ts" };
                 const resolution = nodeModuleNameResolver("foo", containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, moduleFile));
-                checkResolvedModule(resolution.resolvedModule, createTsResolvedModule(moduleFile.name, /*isExternalLibraryImport*/ true));
+                checkResolvedModule(resolution.resolvedModule, createResolvedModule(moduleFile.name, /*isExternalLibraryImport*/ true));
             }
         });
 
@@ -271,90 +247,64 @@ namespace ts {
                 const containingFile = { name: "/a/node_modules/b/c/node_modules/d/e.ts" };
                 const moduleFile = { name: "/a/node_modules/foo/index.d.ts" };
                 const resolution = nodeModuleNameResolver("foo", containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, moduleFile));
-                checkResolvedModuleWithFailedLookupLocations(resolution, createTsResolvedModule(moduleFile.name, /*isExternalLibraryImport*/ true), [
+                checkResolvedModuleWithFailedLookupLocations(resolution, createResolvedModule(moduleFile.name, /*isExternalLibraryImport*/ true), [
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo.ts",
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo.tsx",
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo.d.ts",
-                    "/a/node_modules/b/c/node_modules/d/node_modules/foo.js",
-                    "/a/node_modules/b/c/node_modules/d/node_modules/foo.jsx",
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo/package.json",
 
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo/index.ts",
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo/index.tsx",
                     "/a/node_modules/b/c/node_modules/d/node_modules/foo/index.d.ts",
-                    "/a/node_modules/b/c/node_modules/d/node_modules/foo/index.js",
-                    "/a/node_modules/b/c/node_modules/d/node_modules/foo/index.jsx",
 
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo.ts",
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo.tsx",
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo.d.ts",
-                    "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo.js",
-                    "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo.jsx",
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo/package.json",
 
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo/index.ts",
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo/index.tsx",
                     "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo/index.d.ts",
-                    "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo/index.js",
-                    "/a/node_modules/b/c/node_modules/d/node_modules/@types/foo/index.jsx",
 
                     "/a/node_modules/b/c/node_modules/foo.ts",
                     "/a/node_modules/b/c/node_modules/foo.tsx",
                     "/a/node_modules/b/c/node_modules/foo.d.ts",
-                    "/a/node_modules/b/c/node_modules/foo.js",
-                    "/a/node_modules/b/c/node_modules/foo.jsx",
                     "/a/node_modules/b/c/node_modules/foo/package.json",
 
                     "/a/node_modules/b/c/node_modules/foo/index.ts",
                     "/a/node_modules/b/c/node_modules/foo/index.tsx",
                     "/a/node_modules/b/c/node_modules/foo/index.d.ts",
-                    "/a/node_modules/b/c/node_modules/foo/index.js",
-                    "/a/node_modules/b/c/node_modules/foo/index.jsx",
 
                     "/a/node_modules/b/c/node_modules/@types/foo.ts",
                     "/a/node_modules/b/c/node_modules/@types/foo.tsx",
                     "/a/node_modules/b/c/node_modules/@types/foo.d.ts",
-                    "/a/node_modules/b/c/node_modules/@types/foo.js",
-                    "/a/node_modules/b/c/node_modules/@types/foo.jsx",
                     "/a/node_modules/b/c/node_modules/@types/foo/package.json",
 
                     "/a/node_modules/b/c/node_modules/@types/foo/index.ts",
                     "/a/node_modules/b/c/node_modules/@types/foo/index.tsx",
                     "/a/node_modules/b/c/node_modules/@types/foo/index.d.ts",
-                    "/a/node_modules/b/c/node_modules/@types/foo/index.js",
-                    "/a/node_modules/b/c/node_modules/@types/foo/index.jsx",
 
                     "/a/node_modules/b/node_modules/foo.ts",
                     "/a/node_modules/b/node_modules/foo.tsx",
                     "/a/node_modules/b/node_modules/foo.d.ts",
-                    "/a/node_modules/b/node_modules/foo.js",
-                    "/a/node_modules/b/node_modules/foo.jsx",
                     "/a/node_modules/b/node_modules/foo/package.json",
 
                     "/a/node_modules/b/node_modules/foo/index.ts",
                     "/a/node_modules/b/node_modules/foo/index.tsx",
                     "/a/node_modules/b/node_modules/foo/index.d.ts",
-                    "/a/node_modules/b/node_modules/foo/index.js",
-                    "/a/node_modules/b/node_modules/foo/index.jsx",
 
                     "/a/node_modules/b/node_modules/@types/foo.ts",
                     "/a/node_modules/b/node_modules/@types/foo.tsx",
                     "/a/node_modules/b/node_modules/@types/foo.d.ts",
-                    "/a/node_modules/b/node_modules/@types/foo.js",
-                    "/a/node_modules/b/node_modules/@types/foo.jsx",
                     "/a/node_modules/b/node_modules/@types/foo/package.json",
 
                     "/a/node_modules/b/node_modules/@types/foo/index.ts",
                     "/a/node_modules/b/node_modules/@types/foo/index.tsx",
                     "/a/node_modules/b/node_modules/@types/foo/index.d.ts",
-                    "/a/node_modules/b/node_modules/@types/foo/index.js",
-                    "/a/node_modules/b/node_modules/@types/foo/index.jsx",
 
                     "/a/node_modules/foo.ts",
                     "/a/node_modules/foo.tsx",
                     "/a/node_modules/foo.d.ts",
-                    "/a/node_modules/foo.js",
-                    "/a/node_modules/foo.jsx",
                     "/a/node_modules/foo/package.json",
 
                     "/a/node_modules/foo/index.ts",
@@ -564,15 +514,15 @@ import b = require("./moduleB");
                     const options: CompilerOptions = { moduleResolution, baseUrl: "/root" };
                     {
                         const result = resolveModuleName("folder2/file2", file1.name, options, host);
-                        checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(file2.name), []);
+                        checkResolvedModuleWithFailedLookupLocations(result, createResolvedModule(file2.name), []);
                     }
                     {
                         const result = resolveModuleName("./file3", file2.name, options, host);
-                        checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(file3.name), []);
+                        checkResolvedModuleWithFailedLookupLocations(result, createResolvedModule(file3.name), []);
                     }
                     {
                         const result = resolveModuleName("/root/folder1/file1", file2.name, options, host);
-                        checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(file1.name), []);
+                        checkResolvedModuleWithFailedLookupLocations(result, createResolvedModule(file1.name), []);
                     }
                 }
             }
@@ -601,7 +551,7 @@ import b = require("./moduleB");
 
                 function check(name: string, caller: File, expected: File, isExternalLibraryImport = false) {
                     const result = resolveModuleName(name, caller.name, options, host);
-                    checkResolvedModule(result.resolvedModule, createTsResolvedModule(expected.name, isExternalLibraryImport));
+                    checkResolvedModule(result.resolvedModule, createResolvedModule(expected.name, isExternalLibraryImport));
                 }
             }
         });
@@ -623,7 +573,7 @@ import b = require("./moduleB");
 
                 function check(name: string, caller: File, expected: File) {
                     const result = resolveModuleName(name, caller.name, options, host);
-                    checkResolvedModule(result.resolvedModule, createTsResolvedModule(expected.name));
+                    checkResolvedModule(result.resolvedModule, createResolvedModule(expected.name));
                 }
             }
         });
@@ -664,15 +614,11 @@ import b = require("./moduleB");
                     "/root/folder1/file2.ts",
                     "/root/folder1/file2.tsx",
                     "/root/folder1/file2.d.ts",
-                    "/root/folder1/file2.js",
-                    "/root/folder1/file2.jsx",
                     "/root/folder1/file2/package.json",
 
                     "/root/folder1/file2/index.ts",
                     "/root/folder1/file2/index.tsx",
                     "/root/folder1/file2/index.d.ts",
-                    "/root/folder1/file2/index.js",
-                    "/root/folder1/file2/index.jsx",
                     // then first attempt on 'generated/*' was successful
                 ]);
                 check("folder2/file3", file3, [
@@ -680,22 +626,16 @@ import b = require("./moduleB");
                     "/root/folder2/file3.ts",
                     "/root/folder2/file3.tsx",
                     "/root/folder2/file3.d.ts",
-                    "/root/folder2/file3.js",
-                    "/root/folder2/file3.jsx",
                     "/root/folder2/file3/package.json",
 
                     "/root/folder2/file3/index.ts",
                     "/root/folder2/file3/index.tsx",
                     "/root/folder2/file3/index.d.ts",
-                    "/root/folder2/file3/index.js",
-                    "/root/folder2/file3/index.jsx",
 
                     // then use remapped location
                     "/root/generated/folder2/file3.ts",
                     "/root/generated/folder2/file3.tsx",
                     "/root/generated/folder2/file3.d.ts",
-                    "/root/generated/folder2/file3.js",
-                    "/root/generated/folder2/file3.jsx",
                     "/root/generated/folder2/file3/package.json",
 
                     "/root/generated/folder2/file3/index.ts",
@@ -707,22 +647,16 @@ import b = require("./moduleB");
                     "/root/folder2/file4.ts",
                     "/root/folder2/file4.tsx",
                     "/root/folder2/file4.d.ts",
-                    "/root/folder2/file4.js",
-                    "/root/folder2/file4.jsx",
                     "/root/folder2/file4/package.json",
 
                     "/root/folder2/file4/index.ts",
                     "/root/folder2/file4/index.tsx",
                     "/root/folder2/file4/index.d.ts",
-                    "/root/folder2/file4/index.js",
-                    "/root/folder2/file4/index.jsx",
 
                     // try to load from file from remapped location
                     "/root/generated/folder2/file4.ts",
                     "/root/generated/folder2/file4.tsx",
                     "/root/generated/folder2/file4.d.ts",
-                    "/root/generated/folder2/file4.js",
-                    "/root/generated/folder2/file4.jsx",
                     // success on loading as from folder
                 ]);
                 check("somefolder/file5", file5, [
@@ -731,8 +665,6 @@ import b = require("./moduleB");
                     "/root/someanotherfolder/file5.ts",
                     "/root/someanotherfolder/file5.tsx",
                     "/root/someanotherfolder/file5.d.ts",
-                    "/root/someanotherfolder/file5.js",
-                    "/root/someanotherfolder/file5.jsx",
 
                     // load from folder
                     "/root/someanotherfolder/file5/package.json",
@@ -746,67 +678,51 @@ import b = require("./moduleB");
                     "/root/file6.ts",
                     "/root/file6.tsx",
                     "/root/file6.d.ts",
-                    "/root/file6.js",
-                    "/root/file6.jsx",
 
                     // load from folder
                     "/root/file6/package.json",
                     "/root/file6/index.ts",
                     "/root/file6/index.tsx",
                     "/root/file6/index.d.ts",
-                    "/root/file6/index.js",
-                    "/root/file6/index.jsx",
 
                     // then try 'generated/*'
                     // load from file
                     "/root/generated/file6.ts",
                     "/root/generated/file6.tsx",
                     "/root/generated/file6.d.ts",
-                    "/root/generated/file6.js",
-                    "/root/generated/file6.jsx",
 
                     // load from folder
                     "/root/generated/file6/package.json",
                     "/root/generated/file6/index.ts",
                     "/root/generated/file6/index.tsx",
                     "/root/generated/file6/index.d.ts",
-                    "/root/generated/file6/index.js",
-                    "/root/generated/file6/index.jsx",
 
                     // fallback to standard node behavior
                     // load from file
                     "/root/folder1/node_modules/file6.ts",
                     "/root/folder1/node_modules/file6.tsx",
                     "/root/folder1/node_modules/file6.d.ts",
-                    "/root/folder1/node_modules/file6.js",
-                    "/root/folder1/node_modules/file6.jsx",
 
                     // load from folder
                     "/root/folder1/node_modules/file6/package.json",
                     "/root/folder1/node_modules/file6/index.ts",
                     "/root/folder1/node_modules/file6/index.tsx",
                     "/root/folder1/node_modules/file6/index.d.ts",
-                    "/root/folder1/node_modules/file6/index.js",
-                    "/root/folder1/node_modules/file6/index.jsx",
 
                     "/root/folder1/node_modules/@types/file6.ts",
                     "/root/folder1/node_modules/@types/file6.tsx",
                     "/root/folder1/node_modules/@types/file6.d.ts",
-                    "/root/folder1/node_modules/@types/file6.js",
-                    "/root/folder1/node_modules/@types/file6.jsx",
 
                     "/root/folder1/node_modules/@types/file6/package.json",
                     "/root/folder1/node_modules/@types/file6/index.ts",
                     "/root/folder1/node_modules/@types/file6/index.tsx",
                     "/root/folder1/node_modules/@types/file6/index.d.ts",
-                    "/root/folder1/node_modules/@types/file6/index.js",
-                    "/root/folder1/node_modules/@types/file6/index.jsx",
                     // success on /root/node_modules/file6.ts
                 ], /*isExternalLibraryImport*/ true);
 
                 function check(name: string, expected: File, expectedFailedLookups: string[], isExternalLibraryImport = false) {
                     const result = resolveModuleName(name, main.name, options, host);
-                    checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(expected.name, isExternalLibraryImport), expectedFailedLookups);
+                    checkResolvedModuleWithFailedLookupLocations(result, createResolvedModule(expected.name, isExternalLibraryImport), expectedFailedLookups);
                 }
             }
         });
@@ -843,8 +759,6 @@ import b = require("./moduleB");
                     "/root/folder1/file2.ts",
                     "/root/folder1/file2.tsx",
                     "/root/folder1/file2.d.ts",
-                    "/root/folder1/file2.js",
-                    "/root/folder1/file2.jsx",
                     // success when using 'generated/*'
                 ]);
                 check("folder1/file3", file3, [
@@ -852,30 +766,22 @@ import b = require("./moduleB");
                     "/root/folder1/file3.ts",
                     "/root/folder1/file3.tsx",
                     "/root/folder1/file3.d.ts",
-                    "/root/folder1/file3.js",
-                    "/root/folder1/file3.jsx",
                     // then try 'generated/*'
                     "/root/generated/folder1/file3.ts",
                     "/root/generated/folder1/file3.tsx",
                     "/root/generated/folder1/file3.d.ts",
-                    "/root/generated/folder1/file3.js",
-                    "/root/generated/folder1/file3.jsx",
                     // fallback to classic
                     "/root/folder1/folder1/file3.ts",
                     "/root/folder1/folder1/file3.tsx",
                     "/root/folder1/folder1/file3.d.ts",
-                    "/root/folder1/folder1/file3.js",
-                    "/root/folder1/folder1/file3.jsx",
                     "/root/folder1/file3.ts",
                     "/root/folder1/file3.tsx",
                     "/root/folder1/file3.d.ts",
-                    "/root/folder1/file3.js",
-                    "/root/folder1/file3.jsx",
                 ]);
 
                 function check(name: string, expected: File, expectedFailedLookups: string[]) {
                     const result = resolveModuleName(name, main.name, options, host);
-                    checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(expected.name), expectedFailedLookups);
+                    checkResolvedModuleWithFailedLookupLocations(result, createResolvedModule(expected.name), expectedFailedLookups);
                 }
             }
         });
@@ -903,15 +809,11 @@ import b = require("./moduleB");
                     "/root/folder1/file2.ts",
                     "/root/folder1/file2.tsx",
                     "/root/folder1/file2.d.ts",
-                    "/root/folder1/file2.js",
-                    "/root/folder1/file2.jsx",
                     // load from folder
                     "/root/folder1/file2/package.json",
                     "/root/folder1/file2/index.ts",
                     "/root/folder1/file2/index.tsx",
                     "/root/folder1/file2/index.d.ts",
-                    "/root/folder1/file2/index.js",
-                    "/root/folder1/file2/index.jsx",
                     // success after using alternative rootDir entry
                 ]);
                 check("../folder1/file1", file3, file1, [
@@ -920,15 +822,11 @@ import b = require("./moduleB");
                     "/root/generated/folder1/file1.ts",
                     "/root/generated/folder1/file1.tsx",
                     "/root/generated/folder1/file1.d.ts",
-                    "/root/generated/folder1/file1.js",
-                    "/root/generated/folder1/file1.jsx",
                     // load from module
                     "/root/generated/folder1/file1/package.json",
                     "/root/generated/folder1/file1/index.ts",
                     "/root/generated/folder1/file1/index.tsx",
                     "/root/generated/folder1/file1/index.d.ts",
-                    "/root/generated/folder1/file1/index.js",
-                    "/root/generated/folder1/file1/index.jsx",
                     // success after using alternative rootDir entry
                 ]);
                 check("../folder1/file1_1", file3, file1_1, [
@@ -937,22 +835,16 @@ import b = require("./moduleB");
                     "/root/generated/folder1/file1_1.ts",
                     "/root/generated/folder1/file1_1.tsx",
                     "/root/generated/folder1/file1_1.d.ts",
-                    "/root/generated/folder1/file1_1.js",
-                    "/root/generated/folder1/file1_1.jsx",
                     // load from folder
                     "/root/generated/folder1/file1_1/package.json",
                     "/root/generated/folder1/file1_1/index.ts",
                     "/root/generated/folder1/file1_1/index.tsx",
                     "/root/generated/folder1/file1_1/index.d.ts",
-                    "/root/generated/folder1/file1_1/index.js",
-                    "/root/generated/folder1/file1_1/index.jsx",
                     // try alternative rootDir entry
                     // load from file
                     "/root/folder1/file1_1.ts",
                     "/root/folder1/file1_1.tsx",
                     "/root/folder1/file1_1.d.ts",
-                    "/root/folder1/file1_1.js",
-                    "/root/folder1/file1_1.jsx",
                     // load from directory
                     "/root/folder1/file1_1/package.json",
                     "/root/folder1/file1_1/index.ts",
@@ -962,7 +854,7 @@ import b = require("./moduleB");
 
                 function check(name: string, container: File, expected: File, expectedFailedLookups: string[]) {
                     const result = resolveModuleName(name, container.name, options, host);
-                    checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(expected.name), expectedFailedLookups);
+                    checkResolvedModuleWithFailedLookupLocations(result, createResolvedModule(expected.name), expectedFailedLookups);
                 }
             }
         });
@@ -989,8 +881,6 @@ import b = require("./moduleB");
                     "/root/folder1/file2.ts",
                     "/root/folder1/file2.tsx",
                     "/root/folder1/file2.d.ts",
-                    "/root/folder1/file2.js",
-                    "/root/folder1/file2.jsx",
                     // then try alternative rootDir entry
                 ]);
                 check("../folder1/file1", file3, file1, [
@@ -998,8 +888,6 @@ import b = require("./moduleB");
                     "/root/generated/folder1/file1.ts",
                     "/root/generated/folder1/file1.tsx",
                     "/root/generated/folder1/file1.d.ts",
-                    "/root/generated/folder1/file1.js",
-                    "/root/generated/folder1/file1.jsx",
                     // then try alternative rootDir entry
                 ]);
                 check("folder1/file1_1", file3, file4, [
@@ -1007,26 +895,20 @@ import b = require("./moduleB");
                     "/root/generated/folder2/folder1/file1_1.ts",
                     "/root/generated/folder2/folder1/file1_1.tsx",
                     "/root/generated/folder2/folder1/file1_1.d.ts",
-                    "/root/generated/folder2/folder1/file1_1.js",
-                    "/root/generated/folder2/folder1/file1_1.jsx",
                     // other entry in rootDirs
                     "/root/generated/folder1/file1_1.ts",
                     "/root/generated/folder1/file1_1.tsx",
                     "/root/generated/folder1/file1_1.d.ts",
-                    "/root/generated/folder1/file1_1.js",
-                    "/root/generated/folder1/file1_1.jsx",
                     // fallback
                     "/root/folder1/file1_1.ts",
                     "/root/folder1/file1_1.tsx",
                     "/root/folder1/file1_1.d.ts",
-                    "/root/folder1/file1_1.js",
-                    "/root/folder1/file1_1.jsx",
                     // found one
                 ]);
 
                 function check(name: string, container: File, expected: File, expectedFailedLookups: string[]) {
                     const result = resolveModuleName(name, container.name, options, host);
-                    checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(expected.name), expectedFailedLookups);
+                    checkResolvedModuleWithFailedLookupLocations(result, createResolvedModule(expected.name), expectedFailedLookups);
                 }
             }
         });
@@ -1048,13 +930,11 @@ import b = require("./moduleB");
                     }
                  };
                 const result = resolveModuleName("libs/guid", app.name, options, host);
-                checkResolvedModuleWithFailedLookupLocations(result, createTsResolvedModule(libsTypings.name), [
+                checkResolvedModuleWithFailedLookupLocations(result, createResolvedModule(libsTypings.name), [
                     // first try to load module as file
                     "/root/src/libs/guid.ts",
                     "/root/src/libs/guid.tsx",
                     "/root/src/libs/guid.d.ts",
-                    "/root/src/libs/guid.js",
-                    "/root/src/libs/guid.jsx",
                 ]);
             }
         });
diff --git a/src/harness/unittests/reuseProgramStructure.ts b/src/harness/unittests/reuseProgramStructure.ts
index 66b966aed16ff..f3457b61145a7 100644
--- a/src/harness/unittests/reuseProgramStructure.ts
+++ b/src/harness/unittests/reuseProgramStructure.ts
@@ -295,7 +295,7 @@ namespace ts {
             const options: CompilerOptions = { target };
 
             const program_1 = newProgram(files, ["a.ts"], options);
-            checkResolvedModulesCache(program_1, "a.ts", createMap({ "b": createTsResolvedModule("b.ts") }));
+            checkResolvedModulesCache(program_1, "a.ts", createMap({ "b": createResolvedModule("b.ts") }));
             checkResolvedModulesCache(program_1, "b.ts", undefined);
 
             const program_2 = updateProgram(program_1, ["a.ts"], options, files => {
@@ -304,7 +304,7 @@ namespace ts {
             assert.isTrue(program_1.structureIsReused);
 
             // content of resolution cache should not change
-            checkResolvedModulesCache(program_1, "a.ts", createMap({ "b": createTsResolvedModule("b.ts") }));
+            checkResolvedModulesCache(program_1, "a.ts", createMap({ "b": createResolvedModule("b.ts") }));
             checkResolvedModulesCache(program_1, "b.ts", undefined);
 
             // imports has changed - program is not reused
@@ -321,7 +321,7 @@ namespace ts {
                 files[0].text = files[0].text.updateImportsAndExports(newImports);
             });
             assert.isTrue(!program_3.structureIsReused);
-            checkResolvedModulesCache(program_4, "a.ts", createMap({ "b": createTsResolvedModule("b.ts"), "c": undefined }));
+            checkResolvedModulesCache(program_4, "a.ts", createMap({ "b": createResolvedModule("b.ts"), "c": undefined }));
         });
 
         it("resolved type directives cache follows type directives", () => {
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index c3962c7749419..c65d85c9405ed 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -1667,67 +1667,74 @@ namespace ts.projectSystem {
                 "File '/a/b/node_modules/lib.ts' does not exist.",
                 "File '/a/b/node_modules/lib.tsx' does not exist.",
                 "File '/a/b/node_modules/lib.d.ts' does not exist.",
-                "File '/a/b/node_modules/lib.js' does not exist.",
-                "File '/a/b/node_modules/lib.jsx' does not exist.",
                 "File '/a/b/node_modules/lib/package.json' does not exist.",
                 "File '/a/b/node_modules/lib/index.ts' does not exist.",
                 "File '/a/b/node_modules/lib/index.tsx' does not exist.",
                 "File '/a/b/node_modules/lib/index.d.ts' does not exist.",
-                "File '/a/b/node_modules/lib/index.js' does not exist.",
-                "File '/a/b/node_modules/lib/index.jsx' does not exist.",
                 "File '/a/b/node_modules/@types/lib.ts' does not exist.",
                 "File '/a/b/node_modules/@types/lib.tsx' does not exist.",
                 "File '/a/b/node_modules/@types/lib.d.ts' does not exist.",
-                "File '/a/b/node_modules/@types/lib.js' does not exist.",
-                "File '/a/b/node_modules/@types/lib.jsx' does not exist.",
                 "File '/a/b/node_modules/@types/lib/package.json' does not exist.",
                 "File '/a/b/node_modules/@types/lib/index.ts' does not exist.",
                 "File '/a/b/node_modules/@types/lib/index.tsx' does not exist.",
                 "File '/a/b/node_modules/@types/lib/index.d.ts' does not exist.",
-                "File '/a/b/node_modules/@types/lib/index.js' does not exist.",
-                "File '/a/b/node_modules/@types/lib/index.jsx' does not exist.",
                 "File '/a/node_modules/lib.ts' does not exist.",
                 "File '/a/node_modules/lib.tsx' does not exist.",
                 "File '/a/node_modules/lib.d.ts' does not exist.",
-                "File '/a/node_modules/lib.js' does not exist.",
-                "File '/a/node_modules/lib.jsx' does not exist.",
                 "File '/a/node_modules/lib/package.json' does not exist.",
                 "File '/a/node_modules/lib/index.ts' does not exist.",
                 "File '/a/node_modules/lib/index.tsx' does not exist.",
                 "File '/a/node_modules/lib/index.d.ts' does not exist.",
-                "File '/a/node_modules/lib/index.js' does not exist.",
-                "File '/a/node_modules/lib/index.jsx' does not exist.",
                 "File '/a/node_modules/@types/lib.ts' does not exist.",
                 "File '/a/node_modules/@types/lib.tsx' does not exist.",
                 "File '/a/node_modules/@types/lib.d.ts' does not exist.",
-                "File '/a/node_modules/@types/lib.js' does not exist.",
-                "File '/a/node_modules/@types/lib.jsx' does not exist.",
                 "File '/a/node_modules/@types/lib/package.json' does not exist.",
                 "File '/a/node_modules/@types/lib/index.ts' does not exist.",
                 "File '/a/node_modules/@types/lib/index.tsx' does not exist.",
                 "File '/a/node_modules/@types/lib/index.d.ts' does not exist.",
-                "File '/a/node_modules/@types/lib/index.js' does not exist.",
-                "File '/a/node_modules/@types/lib/index.jsx' does not exist.",
                 "File '/node_modules/lib.ts' does not exist.",
                 "File '/node_modules/lib.tsx' does not exist.",
                 "File '/node_modules/lib.d.ts' does not exist.",
-                "File '/node_modules/lib.js' does not exist.",
-                "File '/node_modules/lib.jsx' does not exist.",
                 "File '/node_modules/lib/package.json' does not exist.",
                 "File '/node_modules/lib/index.ts' does not exist.",
                 "File '/node_modules/lib/index.tsx' does not exist.",
                 "File '/node_modules/lib/index.d.ts' does not exist.",
-                "File '/node_modules/lib/index.js' does not exist.",
-                "File '/node_modules/lib/index.jsx' does not exist.",
                 "File '/node_modules/@types/lib.ts' does not exist.",
                 "File '/node_modules/@types/lib.tsx' does not exist.",
                 "File '/node_modules/@types/lib.d.ts' does not exist.",
-                "File '/node_modules/@types/lib.js' does not exist.",
-                "File '/node_modules/@types/lib.jsx' does not exist.",
                 "File '/node_modules/@types/lib/package.json' does not exist.",
                 "File '/node_modules/@types/lib/index.ts' does not exist.",
                 "File '/node_modules/@types/lib/index.tsx' does not exist.",
                 "File '/node_modules/@types/lib/index.d.ts' does not exist.",
+                "Loading module 'lib' from 'node_modules' folder.",
+                "File '/a/b/node_modules/lib.js' does not exist.",
+                "File '/a/b/node_modules/lib.jsx' does not exist.",
+                "File '/a/b/node_modules/lib/package.json' does not exist.",
+                "File '/a/b/node_modules/lib/index.js' does not exist.",
+                "File '/a/b/node_modules/lib/index.jsx' does not exist.",
+                "File '/a/b/node_modules/@types/lib.js' does not exist.",
+                "File '/a/b/node_modules/@types/lib.jsx' does not exist.",
+                "File '/a/b/node_modules/@types/lib/package.json' does not exist.",
+                "File '/a/b/node_modules/@types/lib/index.js' does not exist.",
+                "File '/a/b/node_modules/@types/lib/index.jsx' does not exist.",
+                "File '/a/node_modules/lib.js' does not exist.",
+                "File '/a/node_modules/lib.jsx' does not exist.",
+                "File '/a/node_modules/lib/package.json' does not exist.",
+                "File '/a/node_modules/lib/index.js' does not exist.",
+                "File '/a/node_modules/lib/index.jsx' does not exist.",
+                "File '/a/node_modules/@types/lib.js' does not exist.",
+                "File '/a/node_modules/@types/lib.jsx' does not exist.",
+                "File '/a/node_modules/@types/lib/package.json' does not exist.",
+                "File '/a/node_modules/@types/lib/index.js' does not exist.",
+                "File '/a/node_modules/@types/lib/index.jsx' does not exist.",
+                "File '/node_modules/lib.js' does not exist.",
+                "File '/node_modules/lib.jsx' does not exist.",
+                "File '/node_modules/lib/package.json' does not exist.",
+                "File '/node_modules/lib/index.js' does not exist.",
+                "File '/node_modules/lib/index.jsx' does not exist.",
+                "File '/node_modules/@types/lib.js' does not exist.",
+                "File '/node_modules/@types/lib.jsx' does not exist.",
+                "File '/node_modules/@types/lib/package.json' does not exist.",
                 "File '/node_modules/@types/lib/index.js' does not exist.",
                 "File '/node_modules/@types/lib/index.jsx' does not exist.",
                 "======== Module name 'lib' was not resolved. ========",
@@ -1735,19 +1742,13 @@ namespace ts.projectSystem {
                 "File '/a/cache/node_modules/lib.ts' does not exist.",
                 "File '/a/cache/node_modules/lib.tsx' does not exist.",
                 "File '/a/cache/node_modules/lib.d.ts' does not exist.",
-                "File '/a/cache/node_modules/lib.js' does not exist.",
-                "File '/a/cache/node_modules/lib.jsx' does not exist.",
                 "File '/a/cache/node_modules/lib/package.json' does not exist.",
                 "File '/a/cache/node_modules/lib/index.ts' does not exist.",
                 "File '/a/cache/node_modules/lib/index.tsx' does not exist.",
                 "File '/a/cache/node_modules/lib/index.d.ts' does not exist.",
-                "File '/a/cache/node_modules/lib/index.js' does not exist.",
-                "File '/a/cache/node_modules/lib/index.jsx' does not exist.",
                 "File '/a/cache/node_modules/@types/lib.ts' does not exist.",
                 "File '/a/cache/node_modules/@types/lib.tsx' does not exist.",
                 "File '/a/cache/node_modules/@types/lib.d.ts' does not exist.",
-                "File '/a/cache/node_modules/@types/lib.js' does not exist.",
-                "File '/a/cache/node_modules/@types/lib.jsx' does not exist.",
                 "File '/a/cache/node_modules/@types/lib/package.json' does not exist.",
                 "File '/a/cache/node_modules/@types/lib/index.ts' does not exist.",
                 "File '/a/cache/node_modules/@types/lib/index.tsx' does not exist.",
diff --git a/src/server/lsHost.ts b/src/server/lsHost.ts
index c95b834b8ebf6..8a8861e412e4a 100644
--- a/src/server/lsHost.ts
+++ b/src/server/lsHost.ts
@@ -25,7 +25,7 @@ namespace ts.server {
                     : undefined;
                 const primaryResult = resolveModuleName(moduleName, containingFile, compilerOptions, host);
                 // return result immediately only if it is .ts, .tsx or .d.ts
-                if (!(primaryResult.resolvedModule && primaryResult.resolvedModule.resolvedTsFileName) && globalCache !== undefined) {
+                if (!(primaryResult.resolvedModule && extensionIsTypeScript(primaryResult.resolvedModule.extension)) && globalCache !== undefined) {
                     // otherwise try to load typings from @types
 
                     // create different collection of failed lookup locations for second pass
diff --git a/src/services/shims.ts b/src/services/shims.ts
index a525ff4398638..82e3d5971f3fb 100644
--- a/src/services/shims.ts
+++ b/src/services/shims.ts
@@ -328,7 +328,7 @@ namespace ts {
                     const resolutionsInFile = <MapLike<string>>JSON.parse(this.shimHost.getModuleResolutionsForFile(containingFile));
                     return map(moduleNames, name => {
                         const result = getProperty(resolutionsInFile, name);
-                        return result ? resolvedModuleFromAnyFile(result, /*isExternalLibraryImport*/ false) : undefined;
+                        return result ? { resolvedFileName: result, extension: extensionFromPath(result), isExternalLibraryImport: false } : undefined;
                     });
                 };
             }
diff --git a/tests/baselines/reference/importWithTrailingSlash_noResolve.trace.json b/tests/baselines/reference/importWithTrailingSlash_noResolve.trace.json
index db316e5db74cd..55b75c57dde4b 100644
--- a/tests/baselines/reference/importWithTrailingSlash_noResolve.trace.json
+++ b/tests/baselines/reference/importWithTrailingSlash_noResolve.trace.json
@@ -6,6 +6,8 @@
     "File '/foo/index.ts' does not exist.",
     "File '/foo/index.tsx' does not exist.",
     "File '/foo/index.d.ts' does not exist.",
+    "Loading module as file / folder, candidate module location '/foo/'.",
+    "File '/foo/package.json' does not exist.",
     "File '/foo/index.js' does not exist.",
     "File '/foo/index.jsx' does not exist.",
     "======== Module name './foo/' was not resolved. ========"
diff --git a/tests/baselines/reference/maxNodeModuleJsDepthDefaultsToZero.trace.json b/tests/baselines/reference/maxNodeModuleJsDepthDefaultsToZero.trace.json
index e53b2a0934fe7..3a9d8c4ea79b1 100644
--- a/tests/baselines/reference/maxNodeModuleJsDepthDefaultsToZero.trace.json
+++ b/tests/baselines/reference/maxNodeModuleJsDepthDefaultsToZero.trace.json
@@ -5,24 +5,22 @@
     "File '/node_modules/shortid.ts' does not exist.",
     "File '/node_modules/shortid.tsx' does not exist.",
     "File '/node_modules/shortid.d.ts' does not exist.",
-    "File '/node_modules/shortid.js' does not exist.",
-    "File '/node_modules/shortid.jsx' does not exist.",
     "File '/node_modules/shortid/package.json' does not exist.",
     "File '/node_modules/shortid/index.ts' does not exist.",
     "File '/node_modules/shortid/index.tsx' does not exist.",
     "File '/node_modules/shortid/index.d.ts' does not exist.",
-    "File '/node_modules/shortid/index.js' exist - use it as a name resolution result.",
     "File '/node_modules/@types/shortid.ts' does not exist.",
     "File '/node_modules/@types/shortid.tsx' does not exist.",
     "File '/node_modules/@types/shortid.d.ts' does not exist.",
-    "File '/node_modules/@types/shortid.js' does not exist.",
-    "File '/node_modules/@types/shortid.jsx' does not exist.",
     "File '/node_modules/@types/shortid/package.json' does not exist.",
     "File '/node_modules/@types/shortid/index.ts' does not exist.",
     "File '/node_modules/@types/shortid/index.tsx' does not exist.",
     "File '/node_modules/@types/shortid/index.d.ts' does not exist.",
-    "File '/node_modules/@types/shortid/index.js' does not exist.",
-    "File '/node_modules/@types/shortid/index.jsx' does not exist.",
+    "Loading module 'shortid' from 'node_modules' folder.",
+    "File '/node_modules/shortid.js' does not exist.",
+    "File '/node_modules/shortid.jsx' does not exist.",
+    "File '/node_modules/shortid/package.json' does not exist.",
+    "File '/node_modules/shortid/index.js' exist - use it as a name resolution result.",
     "Resolving real path for '/node_modules/shortid/index.js', result '/node_modules/shortid/index.js'",
     "======== Module name 'shortid' was successfully resolved to '/node_modules/shortid/index.js'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions.trace.json
index 924860326b891..5060006ac56bd 100644
--- a/tests/baselines/reference/moduleResolutionWithExtensions.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithExtensions.trace.json
@@ -11,8 +11,6 @@
     "File '/src/a.js.ts' does not exist.",
     "File '/src/a.js.tsx' does not exist.",
     "File '/src/a.js.d.ts' does not exist.",
-    "File '/src/a.js.js' does not exist.",
-    "File '/src/a.js.jsx' does not exist.",
     "File name '/src/a.js' has a '.js' extension - stripping it",
     "File '/src/a.ts' exist - use it as a name resolution result.",
     "Resolving real path for '/src/a.ts', result '/src/a.ts'",
@@ -23,8 +21,6 @@
     "File '/src/jquery.js.ts' does not exist.",
     "File '/src/jquery.js.tsx' does not exist.",
     "File '/src/jquery.js.d.ts' does not exist.",
-    "File '/src/jquery.js.js' does not exist.",
-    "File '/src/jquery.js.jsx' does not exist.",
     "File name '/src/jquery.js' has a '.js' extension - stripping it",
     "File '/src/jquery.ts' does not exist.",
     "File '/src/jquery.tsx' does not exist.",
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.errors.txt b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.errors.txt
index f1da7b7728dc2..aa415a95b1b90 100644
--- a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.errors.txt
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.errors.txt
@@ -1,5 +1,5 @@
 /a.ts(1,17): error TS6142: Module './tsx' was resolved to '/tsx.tsx', but '--jsx' is not set.
-/a.ts(2,17): error TS6143: Module './jsx' was resolved to '/jsx.jsx', but '--allowJs' is not set.
+/a.ts(2,17): error TS6142: Module './jsx' was resolved to '/jsx.jsx', but '--jsx' is not set.
 /a.ts(3,16): error TS6143: Module './js' was resolved to '/js.js', but '--allowJs' is not set.
 
 
@@ -9,7 +9,7 @@
 !!! error TS6142: Module './tsx' was resolved to '/tsx.tsx', but '--jsx' is not set.
     import jsx from "./jsx";
                     ~~~~~~~
-!!! error TS6143: Module './jsx' was resolved to '/jsx.jsx', but '--allowJs' is not set.
+!!! error TS6142: Module './jsx' was resolved to '/jsx.jsx', but '--jsx' is not set.
     import js from "./js";
                    ~~~~~~
 !!! error TS6143: Module './js' was resolved to '/js.js', but '--allowJs' is not set.
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.trace.json
index 5628c6fb7afc5..0073abaca3a8a 100644
--- a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported.trace.json
@@ -12,14 +12,13 @@
     "File '/jsx.ts' does not exist.",
     "File '/jsx.tsx' does not exist.",
     "File '/jsx.d.ts' does not exist.",
-    "File '/jsx.js' does not exist.",
-    "File '/jsx.jsx' exist - use it as a name resolution result.",
     "File '/jsx/package.json' does not exist.",
     "File '/jsx/index.ts' does not exist.",
     "File '/jsx/index.tsx' does not exist.",
     "File '/jsx/index.d.ts' does not exist.",
-    "File '/jsx/index.js' does not exist.",
-    "File '/jsx/index.jsx' does not exist.",
+    "Loading module as file / folder, candidate module location '/jsx'.",
+    "File '/jsx.js' does not exist.",
+    "File '/jsx.jsx' exist - use it as a name resolution result.",
     "Resolving real path for '/jsx.jsx', result '/jsx.jsx'",
     "======== Module name './jsx' was successfully resolved to '/jsx.jsx'. ========",
     "======== Resolving module './js' from '/a.ts'. ========",
@@ -28,13 +27,12 @@
     "File '/js.ts' does not exist.",
     "File '/js.tsx' does not exist.",
     "File '/js.d.ts' does not exist.",
-    "File '/js.js' exist - use it as a name resolution result.",
     "File '/js/package.json' does not exist.",
     "File '/js/index.ts' does not exist.",
     "File '/js/index.tsx' does not exist.",
     "File '/js/index.d.ts' does not exist.",
-    "File '/js/index.js' does not exist.",
-    "File '/js/index.jsx' does not exist.",
+    "Loading module as file / folder, candidate module location '/js'.",
+    "File '/js.js' exist - use it as a name resolution result.",
     "Resolving real path for '/js.js', result '/js.js'",
     "======== Module name './js' was successfully resolved to '/js.js'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.trace.json
index 2d6170f9946b4..c366843ce86e6 100644
--- a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported2.trace.json
@@ -5,14 +5,13 @@
     "File '/jsx.ts' does not exist.",
     "File '/jsx.tsx' does not exist.",
     "File '/jsx.d.ts' does not exist.",
-    "File '/jsx.js' does not exist.",
-    "File '/jsx.jsx' exist - use it as a name resolution result.",
     "File '/jsx/package.json' does not exist.",
     "File '/jsx/index.ts' does not exist.",
     "File '/jsx/index.tsx' does not exist.",
     "File '/jsx/index.d.ts' does not exist.",
-    "File '/jsx/index.js' does not exist.",
-    "File '/jsx/index.jsx' does not exist.",
+    "Loading module as file / folder, candidate module location '/jsx'.",
+    "File '/jsx.js' does not exist.",
+    "File '/jsx.jsx' exist - use it as a name resolution result.",
     "Resolving real path for '/jsx.jsx', result '/jsx.jsx'",
     "======== Module name './jsx' was successfully resolved to '/jsx.jsx'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.trace.json
index 150d492145c8c..292472c710c7d 100644
--- a/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_preferTs.trace.json
@@ -5,10 +5,8 @@
     "File '/b.ts' does not exist.",
     "File '/b.tsx' does not exist.",
     "File '/b.d.ts' does not exist.",
-    "File '/b.js' exist - use it as a name resolution result.",
     "File '/b/package.json' does not exist.",
     "File '/b/index.ts' exist - use it as a name resolution result.",
     "Resolving real path for '/b/index.ts', result '/b/index.ts'",
-    "Resolving real path for '/b.js', result '/b.js'",
     "======== Module name './b' was successfully resolved to '/b/index.ts'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.trace.json
index b2b46649529e2..9c6d96fc1907f 100644
--- a/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_withAmbientPresent.trace.json
@@ -5,24 +5,22 @@
     "File '/node_modules/js.ts' does not exist.",
     "File '/node_modules/js.tsx' does not exist.",
     "File '/node_modules/js.d.ts' does not exist.",
-    "File '/node_modules/js.js' does not exist.",
-    "File '/node_modules/js.jsx' does not exist.",
     "File '/node_modules/js/package.json' does not exist.",
     "File '/node_modules/js/index.ts' does not exist.",
     "File '/node_modules/js/index.tsx' does not exist.",
     "File '/node_modules/js/index.d.ts' does not exist.",
-    "File '/node_modules/js/index.js' exist - use it as a name resolution result.",
     "File '/node_modules/@types/js.ts' does not exist.",
     "File '/node_modules/@types/js.tsx' does not exist.",
     "File '/node_modules/@types/js.d.ts' does not exist.",
-    "File '/node_modules/@types/js.js' does not exist.",
-    "File '/node_modules/@types/js.jsx' does not exist.",
     "File '/node_modules/@types/js/package.json' does not exist.",
     "File '/node_modules/@types/js/index.ts' does not exist.",
     "File '/node_modules/@types/js/index.tsx' does not exist.",
     "File '/node_modules/@types/js/index.d.ts' does not exist.",
-    "File '/node_modules/@types/js/index.js' does not exist.",
-    "File '/node_modules/@types/js/index.jsx' does not exist.",
+    "Loading module 'js' from 'node_modules' folder.",
+    "File '/node_modules/js.js' does not exist.",
+    "File '/node_modules/js.jsx' does not exist.",
+    "File '/node_modules/js/package.json' does not exist.",
+    "File '/node_modules/js/index.js' exist - use it as a name resolution result.",
     "Resolving real path for '/node_modules/js/index.js', result '/node_modules/js/index.js'",
     "======== Module name 'js' was successfully resolved to '/node_modules/js/index.js'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithSymlinks.trace.json b/tests/baselines/reference/moduleResolutionWithSymlinks.trace.json
index d69fa7bfb50db..0f4dd90569a05 100644
--- a/tests/baselines/reference/moduleResolutionWithSymlinks.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithSymlinks.trace.json
@@ -5,8 +5,6 @@
     "File '/src/library-a.ts' does not exist.",
     "File '/src/library-a.tsx' does not exist.",
     "File '/src/library-a.d.ts' does not exist.",
-    "File '/src/library-a.js' does not exist.",
-    "File '/src/library-a.jsx' does not exist.",
     "File '/src/library-a/package.json' does not exist.",
     "File '/src/library-a/index.ts' exist - use it as a name resolution result.",
     "Resolving real path for '/src/library-a/index.ts', result '/src/library-a/index.ts'",
@@ -17,8 +15,6 @@
     "File '/src/library-b.ts' does not exist.",
     "File '/src/library-b.tsx' does not exist.",
     "File '/src/library-b.d.ts' does not exist.",
-    "File '/src/library-b.js' does not exist.",
-    "File '/src/library-b.jsx' does not exist.",
     "File '/src/library-b/package.json' does not exist.",
     "File '/src/library-b/index.ts' exist - use it as a name resolution result.",
     "Resolving real path for '/src/library-b/index.ts', result '/src/library-b/index.ts'",
@@ -29,67 +25,74 @@
     "File '/src/library-b/node_modules/library-a.ts' does not exist.",
     "File '/src/library-b/node_modules/library-a.tsx' does not exist.",
     "File '/src/library-b/node_modules/library-a.d.ts' does not exist.",
-    "File '/src/library-b/node_modules/library-a.js' does not exist.",
-    "File '/src/library-b/node_modules/library-a.jsx' does not exist.",
     "File '/src/library-b/node_modules/library-a/package.json' does not exist.",
     "File '/src/library-b/node_modules/library-a/index.ts' does not exist.",
     "File '/src/library-b/node_modules/library-a/index.tsx' does not exist.",
     "File '/src/library-b/node_modules/library-a/index.d.ts' does not exist.",
-    "File '/src/library-b/node_modules/library-a/index.js' does not exist.",
-    "File '/src/library-b/node_modules/library-a/index.jsx' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a.ts' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a.tsx' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a.d.ts' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a.js' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a.jsx' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a/package.json' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a/index.ts' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a/index.tsx' does not exist.",
     "File '/src/library-b/node_modules/@types/library-a/index.d.ts' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a/index.js' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a/index.jsx' does not exist.",
     "File '/src/node_modules/library-a.ts' does not exist.",
     "File '/src/node_modules/library-a.tsx' does not exist.",
     "File '/src/node_modules/library-a.d.ts' does not exist.",
-    "File '/src/node_modules/library-a.js' does not exist.",
-    "File '/src/node_modules/library-a.jsx' does not exist.",
     "File '/src/node_modules/library-a/package.json' does not exist.",
     "File '/src/node_modules/library-a/index.ts' does not exist.",
     "File '/src/node_modules/library-a/index.tsx' does not exist.",
     "File '/src/node_modules/library-a/index.d.ts' does not exist.",
-    "File '/src/node_modules/library-a/index.js' does not exist.",
-    "File '/src/node_modules/library-a/index.jsx' does not exist.",
     "File '/src/node_modules/@types/library-a.ts' does not exist.",
     "File '/src/node_modules/@types/library-a.tsx' does not exist.",
     "File '/src/node_modules/@types/library-a.d.ts' does not exist.",
-    "File '/src/node_modules/@types/library-a.js' does not exist.",
-    "File '/src/node_modules/@types/library-a.jsx' does not exist.",
     "File '/src/node_modules/@types/library-a/package.json' does not exist.",
     "File '/src/node_modules/@types/library-a/index.ts' does not exist.",
     "File '/src/node_modules/@types/library-a/index.tsx' does not exist.",
     "File '/src/node_modules/@types/library-a/index.d.ts' does not exist.",
-    "File '/src/node_modules/@types/library-a/index.js' does not exist.",
-    "File '/src/node_modules/@types/library-a/index.jsx' does not exist.",
     "File '/node_modules/library-a.ts' does not exist.",
     "File '/node_modules/library-a.tsx' does not exist.",
     "File '/node_modules/library-a.d.ts' does not exist.",
-    "File '/node_modules/library-a.js' does not exist.",
-    "File '/node_modules/library-a.jsx' does not exist.",
     "File '/node_modules/library-a/package.json' does not exist.",
     "File '/node_modules/library-a/index.ts' does not exist.",
     "File '/node_modules/library-a/index.tsx' does not exist.",
     "File '/node_modules/library-a/index.d.ts' does not exist.",
-    "File '/node_modules/library-a/index.js' does not exist.",
-    "File '/node_modules/library-a/index.jsx' does not exist.",
     "File '/node_modules/@types/library-a.ts' does not exist.",
     "File '/node_modules/@types/library-a.tsx' does not exist.",
     "File '/node_modules/@types/library-a.d.ts' does not exist.",
-    "File '/node_modules/@types/library-a.js' does not exist.",
-    "File '/node_modules/@types/library-a.jsx' does not exist.",
     "File '/node_modules/@types/library-a/package.json' does not exist.",
     "File '/node_modules/@types/library-a/index.ts' does not exist.",
     "File '/node_modules/@types/library-a/index.tsx' does not exist.",
     "File '/node_modules/@types/library-a/index.d.ts' does not exist.",
+    "Loading module 'library-a' from 'node_modules' folder.",
+    "File '/src/library-b/node_modules/library-a.js' does not exist.",
+    "File '/src/library-b/node_modules/library-a.jsx' does not exist.",
+    "File '/src/library-b/node_modules/library-a/package.json' does not exist.",
+    "File '/src/library-b/node_modules/library-a/index.js' does not exist.",
+    "File '/src/library-b/node_modules/library-a/index.jsx' does not exist.",
+    "File '/src/library-b/node_modules/@types/library-a.js' does not exist.",
+    "File '/src/library-b/node_modules/@types/library-a.jsx' does not exist.",
+    "File '/src/library-b/node_modules/@types/library-a/package.json' does not exist.",
+    "File '/src/library-b/node_modules/@types/library-a/index.js' does not exist.",
+    "File '/src/library-b/node_modules/@types/library-a/index.jsx' does not exist.",
+    "File '/src/node_modules/library-a.js' does not exist.",
+    "File '/src/node_modules/library-a.jsx' does not exist.",
+    "File '/src/node_modules/library-a/package.json' does not exist.",
+    "File '/src/node_modules/library-a/index.js' does not exist.",
+    "File '/src/node_modules/library-a/index.jsx' does not exist.",
+    "File '/src/node_modules/@types/library-a.js' does not exist.",
+    "File '/src/node_modules/@types/library-a.jsx' does not exist.",
+    "File '/src/node_modules/@types/library-a/package.json' does not exist.",
+    "File '/src/node_modules/@types/library-a/index.js' does not exist.",
+    "File '/src/node_modules/@types/library-a/index.jsx' does not exist.",
+    "File '/node_modules/library-a.js' does not exist.",
+    "File '/node_modules/library-a.jsx' does not exist.",
+    "File '/node_modules/library-a/package.json' does not exist.",
+    "File '/node_modules/library-a/index.js' does not exist.",
+    "File '/node_modules/library-a/index.jsx' does not exist.",
+    "File '/node_modules/@types/library-a.js' does not exist.",
+    "File '/node_modules/@types/library-a.jsx' does not exist.",
+    "File '/node_modules/@types/library-a/package.json' does not exist.",
     "File '/node_modules/@types/library-a/index.js' does not exist.",
     "File '/node_modules/@types/library-a/index.jsx' does not exist.",
     "======== Module name 'library-a' was not resolved. ========"
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution3_classic.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution3_classic.trace.json
index 22d93809b1bdd..90b8620e36cf9 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution3_classic.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution3_classic.trace.json
@@ -16,18 +16,12 @@
     "File 'c:/root/file4.ts' does not exist.",
     "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
-    "File 'c:/root/file4.js' does not exist.",
-    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/root/folder2/file4.ts' does not exist.",
     "File 'c:/root/folder2/file4.tsx' does not exist.",
     "File 'c:/root/folder2/file4.d.ts' does not exist.",
-    "File 'c:/root/folder2/file4.js' does not exist.",
-    "File 'c:/root/folder2/file4.jsx' does not exist.",
     "File 'c:/root/file4.ts' does not exist.",
     "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
-    "File 'c:/root/file4.js' does not exist.",
-    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/file4.ts' exist - use it as a name resolution result.",
     "======== Module name 'file4' was successfully resolved to 'c:/file4.ts'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution3_node.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution3_node.trace.json
index 220f0f9c04b04..ab7210d7d020c 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution3_node.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution3_node.trace.json
@@ -21,64 +21,42 @@
     "File 'c:/root/file4.ts' does not exist.",
     "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
-    "File 'c:/root/file4.js' does not exist.",
-    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/root/file4/package.json' does not exist.",
     "File 'c:/root/file4/index.ts' does not exist.",
     "File 'c:/root/file4/index.tsx' does not exist.",
     "File 'c:/root/file4/index.d.ts' does not exist.",
-    "File 'c:/root/file4/index.js' does not exist.",
-    "File 'c:/root/file4/index.jsx' does not exist.",
     "Loading module 'file4' from 'node_modules' folder.",
     "File 'c:/root/folder2/node_modules/file4.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/file4.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/file4.d.ts' does not exist.",
-    "File 'c:/root/folder2/node_modules/file4.js' does not exist.",
-    "File 'c:/root/folder2/node_modules/file4.jsx' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/package.json' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/index.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/index.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/index.d.ts' does not exist.",
-    "File 'c:/root/folder2/node_modules/file4/index.js' does not exist.",
-    "File 'c:/root/folder2/node_modules/file4/index.jsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4.d.ts' does not exist.",
-    "File 'c:/root/folder2/node_modules/@types/file4.js' does not exist.",
-    "File 'c:/root/folder2/node_modules/@types/file4.jsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/package.json' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/index.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/index.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/index.d.ts' does not exist.",
-    "File 'c:/root/folder2/node_modules/@types/file4/index.js' does not exist.",
-    "File 'c:/root/folder2/node_modules/@types/file4/index.jsx' does not exist.",
     "File 'c:/root/node_modules/file4.ts' does not exist.",
     "File 'c:/root/node_modules/file4.tsx' does not exist.",
     "File 'c:/root/node_modules/file4.d.ts' does not exist.",
-    "File 'c:/root/node_modules/file4.js' does not exist.",
-    "File 'c:/root/node_modules/file4.jsx' does not exist.",
     "File 'c:/root/node_modules/file4/package.json' does not exist.",
     "File 'c:/root/node_modules/file4/index.ts' does not exist.",
     "File 'c:/root/node_modules/file4/index.tsx' does not exist.",
     "File 'c:/root/node_modules/file4/index.d.ts' does not exist.",
-    "File 'c:/root/node_modules/file4/index.js' does not exist.",
-    "File 'c:/root/node_modules/file4/index.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4.ts' does not exist.",
     "File 'c:/root/node_modules/@types/file4.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4.d.ts' does not exist.",
-    "File 'c:/root/node_modules/@types/file4.js' does not exist.",
-    "File 'c:/root/node_modules/@types/file4.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4/package.json' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.ts' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.d.ts' does not exist.",
-    "File 'c:/root/node_modules/@types/file4/index.js' does not exist.",
-    "File 'c:/root/node_modules/@types/file4/index.jsx' does not exist.",
     "File 'c:/node_modules/file4.ts' does not exist.",
     "File 'c:/node_modules/file4.tsx' does not exist.",
     "File 'c:/node_modules/file4.d.ts' does not exist.",
-    "File 'c:/node_modules/file4.js' does not exist.",
-    "File 'c:/node_modules/file4.jsx' does not exist.",
     "File 'c:/node_modules/file4/package.json' does not exist.",
     "File 'c:/node_modules/file4/index.ts' does not exist.",
     "File 'c:/node_modules/file4/index.tsx' does not exist.",
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution4_classic.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution4_classic.trace.json
index 22d93809b1bdd..90b8620e36cf9 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution4_classic.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution4_classic.trace.json
@@ -16,18 +16,12 @@
     "File 'c:/root/file4.ts' does not exist.",
     "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
-    "File 'c:/root/file4.js' does not exist.",
-    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/root/folder2/file4.ts' does not exist.",
     "File 'c:/root/folder2/file4.tsx' does not exist.",
     "File 'c:/root/folder2/file4.d.ts' does not exist.",
-    "File 'c:/root/folder2/file4.js' does not exist.",
-    "File 'c:/root/folder2/file4.jsx' does not exist.",
     "File 'c:/root/file4.ts' does not exist.",
     "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
-    "File 'c:/root/file4.js' does not exist.",
-    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/file4.ts' exist - use it as a name resolution result.",
     "======== Module name 'file4' was successfully resolved to 'c:/file4.ts'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution4_node.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution4_node.trace.json
index 220f0f9c04b04..ab7210d7d020c 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution4_node.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution4_node.trace.json
@@ -21,64 +21,42 @@
     "File 'c:/root/file4.ts' does not exist.",
     "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
-    "File 'c:/root/file4.js' does not exist.",
-    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/root/file4/package.json' does not exist.",
     "File 'c:/root/file4/index.ts' does not exist.",
     "File 'c:/root/file4/index.tsx' does not exist.",
     "File 'c:/root/file4/index.d.ts' does not exist.",
-    "File 'c:/root/file4/index.js' does not exist.",
-    "File 'c:/root/file4/index.jsx' does not exist.",
     "Loading module 'file4' from 'node_modules' folder.",
     "File 'c:/root/folder2/node_modules/file4.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/file4.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/file4.d.ts' does not exist.",
-    "File 'c:/root/folder2/node_modules/file4.js' does not exist.",
-    "File 'c:/root/folder2/node_modules/file4.jsx' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/package.json' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/index.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/index.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/file4/index.d.ts' does not exist.",
-    "File 'c:/root/folder2/node_modules/file4/index.js' does not exist.",
-    "File 'c:/root/folder2/node_modules/file4/index.jsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4.d.ts' does not exist.",
-    "File 'c:/root/folder2/node_modules/@types/file4.js' does not exist.",
-    "File 'c:/root/folder2/node_modules/@types/file4.jsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/package.json' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/index.ts' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/index.tsx' does not exist.",
     "File 'c:/root/folder2/node_modules/@types/file4/index.d.ts' does not exist.",
-    "File 'c:/root/folder2/node_modules/@types/file4/index.js' does not exist.",
-    "File 'c:/root/folder2/node_modules/@types/file4/index.jsx' does not exist.",
     "File 'c:/root/node_modules/file4.ts' does not exist.",
     "File 'c:/root/node_modules/file4.tsx' does not exist.",
     "File 'c:/root/node_modules/file4.d.ts' does not exist.",
-    "File 'c:/root/node_modules/file4.js' does not exist.",
-    "File 'c:/root/node_modules/file4.jsx' does not exist.",
     "File 'c:/root/node_modules/file4/package.json' does not exist.",
     "File 'c:/root/node_modules/file4/index.ts' does not exist.",
     "File 'c:/root/node_modules/file4/index.tsx' does not exist.",
     "File 'c:/root/node_modules/file4/index.d.ts' does not exist.",
-    "File 'c:/root/node_modules/file4/index.js' does not exist.",
-    "File 'c:/root/node_modules/file4/index.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4.ts' does not exist.",
     "File 'c:/root/node_modules/@types/file4.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4.d.ts' does not exist.",
-    "File 'c:/root/node_modules/@types/file4.js' does not exist.",
-    "File 'c:/root/node_modules/@types/file4.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4/package.json' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.ts' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.d.ts' does not exist.",
-    "File 'c:/root/node_modules/@types/file4/index.js' does not exist.",
-    "File 'c:/root/node_modules/@types/file4/index.jsx' does not exist.",
     "File 'c:/node_modules/file4.ts' does not exist.",
     "File 'c:/node_modules/file4.tsx' does not exist.",
     "File 'c:/node_modules/file4.d.ts' does not exist.",
-    "File 'c:/node_modules/file4.js' does not exist.",
-    "File 'c:/node_modules/file4.jsx' does not exist.",
     "File 'c:/node_modules/file4/package.json' does not exist.",
     "File 'c:/node_modules/file4/index.ts' does not exist.",
     "File 'c:/node_modules/file4/index.tsx' does not exist.",
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution5_classic.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution5_classic.trace.json
index 8fd0dee8e747e..6c899bf028e62 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution5_classic.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution5_classic.trace.json
@@ -16,8 +16,6 @@
     "File 'c:/root/folder3/file2.ts' does not exist.",
     "File 'c:/root/folder3/file2.tsx' does not exist.",
     "File 'c:/root/folder3/file2.d.ts' does not exist.",
-    "File 'c:/root/folder3/file2.js' does not exist.",
-    "File 'c:/root/folder3/file2.jsx' does not exist.",
     "Trying substitution 'generated/*', candidate module location: 'generated/folder3/file2'.",
     "File 'c:/root/generated/folder3/file2.ts' exist - use it as a name resolution result.",
     "======== Module name 'folder3/file2' was successfully resolved to 'c:/root/generated/folder3/file2.ts'. ========",
@@ -38,24 +36,16 @@
     "File 'c:/root/file4.ts' does not exist.",
     "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
-    "File 'c:/root/file4.js' does not exist.",
-    "File 'c:/root/file4.jsx' does not exist.",
     "Trying substitution 'generated/*', candidate module location: 'generated/file4'.",
     "File 'c:/root/generated/file4.ts' does not exist.",
     "File 'c:/root/generated/file4.tsx' does not exist.",
     "File 'c:/root/generated/file4.d.ts' does not exist.",
-    "File 'c:/root/generated/file4.js' does not exist.",
-    "File 'c:/root/generated/file4.jsx' does not exist.",
     "File 'c:/root/folder1/file4.ts' does not exist.",
     "File 'c:/root/folder1/file4.tsx' does not exist.",
     "File 'c:/root/folder1/file4.d.ts' does not exist.",
-    "File 'c:/root/folder1/file4.js' does not exist.",
-    "File 'c:/root/folder1/file4.jsx' does not exist.",
     "File 'c:/root/file4.ts' does not exist.",
     "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
-    "File 'c:/root/file4.js' does not exist.",
-    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/file4.ts' exist - use it as a name resolution result.",
     "======== Module name 'file4' was successfully resolved to 'c:/file4.ts'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution5_node.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution5_node.trace.json
index 8201ed793523e..2efeefa24e5ca 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution5_node.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution5_node.trace.json
@@ -19,14 +19,10 @@
     "File 'c:/root/folder3/file2.ts' does not exist.",
     "File 'c:/root/folder3/file2.tsx' does not exist.",
     "File 'c:/root/folder3/file2.d.ts' does not exist.",
-    "File 'c:/root/folder3/file2.js' does not exist.",
-    "File 'c:/root/folder3/file2.jsx' does not exist.",
     "File 'c:/root/folder3/file2/package.json' does not exist.",
     "File 'c:/root/folder3/file2/index.ts' does not exist.",
     "File 'c:/root/folder3/file2/index.tsx' does not exist.",
     "File 'c:/root/folder3/file2/index.d.ts' does not exist.",
-    "File 'c:/root/folder3/file2/index.js' does not exist.",
-    "File 'c:/root/folder3/file2/index.jsx' does not exist.",
     "Trying substitution 'generated/*', candidate module location: 'generated/folder3/file2'.",
     "Loading module as file / folder, candidate module location 'c:/root/generated/folder3/file2'.",
     "File 'c:/root/generated/folder3/file2.ts' exist - use it as a name resolution result.",
@@ -42,8 +38,6 @@
     "File 'c:/root/shared/components/file3.ts' does not exist.",
     "File 'c:/root/shared/components/file3.tsx' does not exist.",
     "File 'c:/root/shared/components/file3.d.ts' does not exist.",
-    "File 'c:/root/shared/components/file3.js' does not exist.",
-    "File 'c:/root/shared/components/file3.jsx' does not exist.",
     "File 'c:/root/shared/components/file3/package.json' does not exist.",
     "File 'c:/root/shared/components/file3/index.ts' does not exist.",
     "File 'c:/root/shared/components/file3/index.tsx' does not exist.",
@@ -60,72 +54,48 @@
     "File 'c:/root/file4.ts' does not exist.",
     "File 'c:/root/file4.tsx' does not exist.",
     "File 'c:/root/file4.d.ts' does not exist.",
-    "File 'c:/root/file4.js' does not exist.",
-    "File 'c:/root/file4.jsx' does not exist.",
     "File 'c:/root/file4/package.json' does not exist.",
     "File 'c:/root/file4/index.ts' does not exist.",
     "File 'c:/root/file4/index.tsx' does not exist.",
     "File 'c:/root/file4/index.d.ts' does not exist.",
-    "File 'c:/root/file4/index.js' does not exist.",
-    "File 'c:/root/file4/index.jsx' does not exist.",
     "Trying substitution 'generated/*', candidate module location: 'generated/file4'.",
     "Loading module as file / folder, candidate module location 'c:/root/generated/file4'.",
     "File 'c:/root/generated/file4.ts' does not exist.",
     "File 'c:/root/generated/file4.tsx' does not exist.",
     "File 'c:/root/generated/file4.d.ts' does not exist.",
-    "File 'c:/root/generated/file4.js' does not exist.",
-    "File 'c:/root/generated/file4.jsx' does not exist.",
     "File 'c:/root/generated/file4/package.json' does not exist.",
     "File 'c:/root/generated/file4/index.ts' does not exist.",
     "File 'c:/root/generated/file4/index.tsx' does not exist.",
     "File 'c:/root/generated/file4/index.d.ts' does not exist.",
-    "File 'c:/root/generated/file4/index.js' does not exist.",
-    "File 'c:/root/generated/file4/index.jsx' does not exist.",
     "Loading module 'file4' from 'node_modules' folder.",
     "File 'c:/root/folder1/node_modules/file4.ts' does not exist.",
     "File 'c:/root/folder1/node_modules/file4.tsx' does not exist.",
     "File 'c:/root/folder1/node_modules/file4.d.ts' does not exist.",
-    "File 'c:/root/folder1/node_modules/file4.js' does not exist.",
-    "File 'c:/root/folder1/node_modules/file4.jsx' does not exist.",
     "File 'c:/root/folder1/node_modules/file4/package.json' does not exist.",
     "File 'c:/root/folder1/node_modules/file4/index.ts' does not exist.",
     "File 'c:/root/folder1/node_modules/file4/index.tsx' does not exist.",
     "File 'c:/root/folder1/node_modules/file4/index.d.ts' does not exist.",
-    "File 'c:/root/folder1/node_modules/file4/index.js' does not exist.",
-    "File 'c:/root/folder1/node_modules/file4/index.jsx' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4.ts' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4.tsx' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4.d.ts' does not exist.",
-    "File 'c:/root/folder1/node_modules/@types/file4.js' does not exist.",
-    "File 'c:/root/folder1/node_modules/@types/file4.jsx' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4/package.json' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4/index.ts' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4/index.tsx' does not exist.",
     "File 'c:/root/folder1/node_modules/@types/file4/index.d.ts' does not exist.",
-    "File 'c:/root/folder1/node_modules/@types/file4/index.js' does not exist.",
-    "File 'c:/root/folder1/node_modules/@types/file4/index.jsx' does not exist.",
     "File 'c:/root/node_modules/file4.ts' does not exist.",
     "File 'c:/root/node_modules/file4.tsx' does not exist.",
     "File 'c:/root/node_modules/file4.d.ts' does not exist.",
-    "File 'c:/root/node_modules/file4.js' does not exist.",
-    "File 'c:/root/node_modules/file4.jsx' does not exist.",
     "File 'c:/root/node_modules/file4/package.json' does not exist.",
     "File 'c:/root/node_modules/file4/index.ts' does not exist.",
     "File 'c:/root/node_modules/file4/index.tsx' does not exist.",
     "File 'c:/root/node_modules/file4/index.d.ts' does not exist.",
-    "File 'c:/root/node_modules/file4/index.js' does not exist.",
-    "File 'c:/root/node_modules/file4/index.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4.ts' does not exist.",
     "File 'c:/root/node_modules/@types/file4.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4.d.ts' does not exist.",
-    "File 'c:/root/node_modules/@types/file4.js' does not exist.",
-    "File 'c:/root/node_modules/@types/file4.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4/package.json' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.ts' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/file4/index.d.ts' does not exist.",
-    "File 'c:/root/node_modules/@types/file4/index.js' does not exist.",
-    "File 'c:/root/node_modules/@types/file4/index.jsx' does not exist.",
     "File 'c:/node_modules/file4.ts' exist - use it as a name resolution result.",
     "Resolving real path for 'c:/node_modules/file4.ts', result 'c:/node_modules/file4.ts'",
     "======== Module name 'file4' was successfully resolved to 'c:/node_modules/file4.ts'. ========"
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution6_classic.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution6_classic.trace.json
index d6c6b1a45bcc7..d50a6c78ed710 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution6_classic.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution6_classic.trace.json
@@ -9,8 +9,6 @@
     "File 'c:/root/src/project/file3.ts' does not exist.",
     "File 'c:/root/src/project/file3.tsx' does not exist.",
     "File 'c:/root/src/project/file3.d.ts' does not exist.",
-    "File 'c:/root/src/project/file3.js' does not exist.",
-    "File 'c:/root/src/project/file3.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'project/file3' from the root dir 'c:/root/generated/src', candidate location 'c:/root/generated/src/project/file3'",
     "File 'c:/root/generated/src/project/file3.ts' exist - use it as a name resolution result.",
@@ -25,8 +23,6 @@
     "File 'c:/root/generated/src/file2.ts' does not exist.",
     "File 'c:/root/generated/src/file2.tsx' does not exist.",
     "File 'c:/root/generated/src/file2.d.ts' does not exist.",
-    "File 'c:/root/generated/src/file2.js' does not exist.",
-    "File 'c:/root/generated/src/file2.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'file2' from the root dir 'c:/root/src', candidate location 'c:/root/src/file2'",
     "File 'c:/root/src/file2.ts' does not exist.",
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution6_node.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution6_node.trace.json
index 92eb9ad072cb2..28e51a119152d 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution6_node.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution6_node.trace.json
@@ -10,14 +10,10 @@
     "File 'c:/root/src/project/file3.ts' does not exist.",
     "File 'c:/root/src/project/file3.tsx' does not exist.",
     "File 'c:/root/src/project/file3.d.ts' does not exist.",
-    "File 'c:/root/src/project/file3.js' does not exist.",
-    "File 'c:/root/src/project/file3.jsx' does not exist.",
     "File 'c:/root/src/project/file3/package.json' does not exist.",
     "File 'c:/root/src/project/file3/index.ts' does not exist.",
     "File 'c:/root/src/project/file3/index.tsx' does not exist.",
     "File 'c:/root/src/project/file3/index.d.ts' does not exist.",
-    "File 'c:/root/src/project/file3/index.js' does not exist.",
-    "File 'c:/root/src/project/file3/index.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'project/file3' from the root dir 'c:/root/generated/src', candidate location 'c:/root/generated/src/project/file3'",
     "Loading module as file / folder, candidate module location 'c:/root/generated/src/project/file3'.",
@@ -35,22 +31,16 @@
     "File 'c:/root/generated/src/file2.ts' does not exist.",
     "File 'c:/root/generated/src/file2.tsx' does not exist.",
     "File 'c:/root/generated/src/file2.d.ts' does not exist.",
-    "File 'c:/root/generated/src/file2.js' does not exist.",
-    "File 'c:/root/generated/src/file2.jsx' does not exist.",
     "File 'c:/root/generated/src/file2/package.json' does not exist.",
     "File 'c:/root/generated/src/file2/index.ts' does not exist.",
     "File 'c:/root/generated/src/file2/index.tsx' does not exist.",
     "File 'c:/root/generated/src/file2/index.d.ts' does not exist.",
-    "File 'c:/root/generated/src/file2/index.js' does not exist.",
-    "File 'c:/root/generated/src/file2/index.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'file2' from the root dir 'c:/root/src', candidate location 'c:/root/src/file2'",
     "Loading module as file / folder, candidate module location 'c:/root/src/file2'.",
     "File 'c:/root/src/file2.ts' does not exist.",
     "File 'c:/root/src/file2.tsx' does not exist.",
     "File 'c:/root/src/file2.d.ts' does not exist.",
-    "File 'c:/root/src/file2.js' does not exist.",
-    "File 'c:/root/src/file2.jsx' does not exist.",
     "File 'c:/root/src/file2/package.json' does not exist.",
     "File 'c:/root/src/file2/index.ts' does not exist.",
     "File 'c:/root/src/file2/index.tsx' does not exist.",
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution7_classic.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution7_classic.trace.json
index 24d43809bab14..85373855eb584 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution7_classic.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution7_classic.trace.json
@@ -9,8 +9,6 @@
     "File 'c:/root/src/project/file2.ts' does not exist.",
     "File 'c:/root/src/project/file2.tsx' does not exist.",
     "File 'c:/root/src/project/file2.d.ts' does not exist.",
-    "File 'c:/root/src/project/file2.js' does not exist.",
-    "File 'c:/root/src/project/file2.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'project/file2' from the root dir 'c:/root/generated/src', candidate location 'c:/root/generated/src/project/file2'",
     "File 'c:/root/generated/src/project/file2.ts' exist - use it as a name resolution result.",
@@ -24,24 +22,16 @@
     "File 'c:/root/module3.ts' does not exist.",
     "File 'c:/root/module3.tsx' does not exist.",
     "File 'c:/root/module3.d.ts' does not exist.",
-    "File 'c:/root/module3.js' does not exist.",
-    "File 'c:/root/module3.jsx' does not exist.",
     "Trying substitution 'c:/shared/*', candidate module location: 'c:/shared/module3'.",
     "File 'c:/shared/module3.ts' does not exist.",
     "File 'c:/shared/module3.tsx' does not exist.",
     "File 'c:/shared/module3.d.ts' does not exist.",
-    "File 'c:/shared/module3.js' does not exist.",
-    "File 'c:/shared/module3.jsx' does not exist.",
     "File 'c:/root/src/module3.ts' does not exist.",
     "File 'c:/root/src/module3.tsx' does not exist.",
     "File 'c:/root/src/module3.d.ts' does not exist.",
-    "File 'c:/root/src/module3.js' does not exist.",
-    "File 'c:/root/src/module3.jsx' does not exist.",
     "File 'c:/root/module3.ts' does not exist.",
     "File 'c:/root/module3.tsx' does not exist.",
     "File 'c:/root/module3.d.ts' does not exist.",
-    "File 'c:/root/module3.js' does not exist.",
-    "File 'c:/root/module3.jsx' does not exist.",
     "File 'c:/module3.ts' does not exist.",
     "File 'c:/module3.tsx' does not exist.",
     "File 'c:/module3.d.ts' exist - use it as a name resolution result.",
@@ -55,8 +45,6 @@
     "File 'c:/root/module1.ts' does not exist.",
     "File 'c:/root/module1.tsx' does not exist.",
     "File 'c:/root/module1.d.ts' does not exist.",
-    "File 'c:/root/module1.js' does not exist.",
-    "File 'c:/root/module1.jsx' does not exist.",
     "Trying substitution 'c:/shared/*', candidate module location: 'c:/shared/module1'.",
     "File 'c:/shared/module1.ts' does not exist.",
     "File 'c:/shared/module1.tsx' does not exist.",
@@ -80,8 +68,6 @@
     "File 'c:/root/generated/src/file3.ts' does not exist.",
     "File 'c:/root/generated/src/file3.tsx' does not exist.",
     "File 'c:/root/generated/src/file3.d.ts' does not exist.",
-    "File 'c:/root/generated/src/file3.js' does not exist.",
-    "File 'c:/root/generated/src/file3.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'file3' from the root dir 'c:/root/src', candidate location 'c:/root/src/file3'",
     "File 'c:/root/src/file3.ts' does not exist.",
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution7_node.trace.json b/tests/baselines/reference/pathMappingBasedModuleResolution7_node.trace.json
index 003f56463fb05..48633c85e3b48 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution7_node.trace.json
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution7_node.trace.json
@@ -10,14 +10,10 @@
     "File 'c:/root/src/project/file2.ts' does not exist.",
     "File 'c:/root/src/project/file2.tsx' does not exist.",
     "File 'c:/root/src/project/file2.d.ts' does not exist.",
-    "File 'c:/root/src/project/file2.js' does not exist.",
-    "File 'c:/root/src/project/file2.jsx' does not exist.",
     "File 'c:/root/src/project/file2/package.json' does not exist.",
     "File 'c:/root/src/project/file2/index.ts' does not exist.",
     "File 'c:/root/src/project/file2/index.tsx' does not exist.",
     "File 'c:/root/src/project/file2/index.d.ts' does not exist.",
-    "File 'c:/root/src/project/file2/index.js' does not exist.",
-    "File 'c:/root/src/project/file2/index.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'project/file2' from the root dir 'c:/root/generated/src', candidate location 'c:/root/generated/src/project/file2'",
     "Loading module as file / folder, candidate module location 'c:/root/generated/src/project/file2'.",
@@ -34,72 +30,48 @@
     "File 'c:/root/module3.ts' does not exist.",
     "File 'c:/root/module3.tsx' does not exist.",
     "File 'c:/root/module3.d.ts' does not exist.",
-    "File 'c:/root/module3.js' does not exist.",
-    "File 'c:/root/module3.jsx' does not exist.",
     "File 'c:/root/module3/package.json' does not exist.",
     "File 'c:/root/module3/index.ts' does not exist.",
     "File 'c:/root/module3/index.tsx' does not exist.",
     "File 'c:/root/module3/index.d.ts' does not exist.",
-    "File 'c:/root/module3/index.js' does not exist.",
-    "File 'c:/root/module3/index.jsx' does not exist.",
     "Trying substitution 'c:/shared/*', candidate module location: 'c:/shared/module3'.",
     "Loading module as file / folder, candidate module location 'c:/shared/module3'.",
     "File 'c:/shared/module3.ts' does not exist.",
     "File 'c:/shared/module3.tsx' does not exist.",
     "File 'c:/shared/module3.d.ts' does not exist.",
-    "File 'c:/shared/module3.js' does not exist.",
-    "File 'c:/shared/module3.jsx' does not exist.",
     "File 'c:/shared/module3/package.json' does not exist.",
     "File 'c:/shared/module3/index.ts' does not exist.",
     "File 'c:/shared/module3/index.tsx' does not exist.",
     "File 'c:/shared/module3/index.d.ts' does not exist.",
-    "File 'c:/shared/module3/index.js' does not exist.",
-    "File 'c:/shared/module3/index.jsx' does not exist.",
     "Loading module 'module3' from 'node_modules' folder.",
     "File 'c:/root/src/node_modules/module3.ts' does not exist.",
     "File 'c:/root/src/node_modules/module3.tsx' does not exist.",
     "File 'c:/root/src/node_modules/module3.d.ts' does not exist.",
-    "File 'c:/root/src/node_modules/module3.js' does not exist.",
-    "File 'c:/root/src/node_modules/module3.jsx' does not exist.",
     "File 'c:/root/src/node_modules/module3/package.json' does not exist.",
     "File 'c:/root/src/node_modules/module3/index.ts' does not exist.",
     "File 'c:/root/src/node_modules/module3/index.tsx' does not exist.",
     "File 'c:/root/src/node_modules/module3/index.d.ts' does not exist.",
-    "File 'c:/root/src/node_modules/module3/index.js' does not exist.",
-    "File 'c:/root/src/node_modules/module3/index.jsx' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3.ts' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3.tsx' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3.d.ts' does not exist.",
-    "File 'c:/root/src/node_modules/@types/module3.js' does not exist.",
-    "File 'c:/root/src/node_modules/@types/module3.jsx' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3/package.json' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3/index.ts' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3/index.tsx' does not exist.",
     "File 'c:/root/src/node_modules/@types/module3/index.d.ts' does not exist.",
-    "File 'c:/root/src/node_modules/@types/module3/index.js' does not exist.",
-    "File 'c:/root/src/node_modules/@types/module3/index.jsx' does not exist.",
     "File 'c:/root/node_modules/module3.ts' does not exist.",
     "File 'c:/root/node_modules/module3.tsx' does not exist.",
     "File 'c:/root/node_modules/module3.d.ts' does not exist.",
-    "File 'c:/root/node_modules/module3.js' does not exist.",
-    "File 'c:/root/node_modules/module3.jsx' does not exist.",
     "File 'c:/root/node_modules/module3/package.json' does not exist.",
     "File 'c:/root/node_modules/module3/index.ts' does not exist.",
     "File 'c:/root/node_modules/module3/index.tsx' does not exist.",
     "File 'c:/root/node_modules/module3/index.d.ts' does not exist.",
-    "File 'c:/root/node_modules/module3/index.js' does not exist.",
-    "File 'c:/root/node_modules/module3/index.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/module3.ts' does not exist.",
     "File 'c:/root/node_modules/@types/module3.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/module3.d.ts' does not exist.",
-    "File 'c:/root/node_modules/@types/module3.js' does not exist.",
-    "File 'c:/root/node_modules/@types/module3.jsx' does not exist.",
     "File 'c:/root/node_modules/@types/module3/package.json' does not exist.",
     "File 'c:/root/node_modules/@types/module3/index.ts' does not exist.",
     "File 'c:/root/node_modules/@types/module3/index.tsx' does not exist.",
     "File 'c:/root/node_modules/@types/module3/index.d.ts' does not exist.",
-    "File 'c:/root/node_modules/@types/module3/index.js' does not exist.",
-    "File 'c:/root/node_modules/@types/module3/index.jsx' does not exist.",
     "File 'c:/node_modules/module3.ts' does not exist.",
     "File 'c:/node_modules/module3.tsx' does not exist.",
     "File 'c:/node_modules/module3.d.ts' exist - use it as a name resolution result.",
@@ -115,21 +87,15 @@
     "File 'c:/root/module1.ts' does not exist.",
     "File 'c:/root/module1.tsx' does not exist.",
     "File 'c:/root/module1.d.ts' does not exist.",
-    "File 'c:/root/module1.js' does not exist.",
-    "File 'c:/root/module1.jsx' does not exist.",
     "File 'c:/root/module1/package.json' does not exist.",
     "File 'c:/root/module1/index.ts' does not exist.",
     "File 'c:/root/module1/index.tsx' does not exist.",
     "File 'c:/root/module1/index.d.ts' does not exist.",
-    "File 'c:/root/module1/index.js' does not exist.",
-    "File 'c:/root/module1/index.jsx' does not exist.",
     "Trying substitution 'c:/shared/*', candidate module location: 'c:/shared/module1'.",
     "Loading module as file / folder, candidate module location 'c:/shared/module1'.",
     "File 'c:/shared/module1.ts' does not exist.",
     "File 'c:/shared/module1.tsx' does not exist.",
     "File 'c:/shared/module1.d.ts' does not exist.",
-    "File 'c:/shared/module1.js' does not exist.",
-    "File 'c:/shared/module1.jsx' does not exist.",
     "File 'c:/shared/module1/package.json' does not exist.",
     "File 'c:/shared/module1/index.ts' does not exist.",
     "File 'c:/shared/module1/index.tsx' does not exist.",
@@ -157,22 +123,16 @@
     "File 'c:/root/generated/src/file3.ts' does not exist.",
     "File 'c:/root/generated/src/file3.tsx' does not exist.",
     "File 'c:/root/generated/src/file3.d.ts' does not exist.",
-    "File 'c:/root/generated/src/file3.js' does not exist.",
-    "File 'c:/root/generated/src/file3.jsx' does not exist.",
     "File 'c:/root/generated/src/file3/package.json' does not exist.",
     "File 'c:/root/generated/src/file3/index.ts' does not exist.",
     "File 'c:/root/generated/src/file3/index.tsx' does not exist.",
     "File 'c:/root/generated/src/file3/index.d.ts' does not exist.",
-    "File 'c:/root/generated/src/file3/index.js' does not exist.",
-    "File 'c:/root/generated/src/file3/index.jsx' does not exist.",
     "Trying other entries in 'rootDirs'",
     "Loading 'file3' from the root dir 'c:/root/src', candidate location 'c:/root/src/file3'",
     "Loading module as file / folder, candidate module location 'c:/root/src/file3'.",
     "File 'c:/root/src/file3.ts' does not exist.",
     "File 'c:/root/src/file3.tsx' does not exist.",
     "File 'c:/root/src/file3.d.ts' does not exist.",
-    "File 'c:/root/src/file3.js' does not exist.",
-    "File 'c:/root/src/file3.jsx' does not exist.",
     "File 'c:/root/src/file3/package.json' does not exist.",
     "File 'c:/root/src/file3/index.ts' does not exist.",
     "File 'c:/root/src/file3/index.tsx' does not exist.",
diff --git a/tests/baselines/reference/typeRootsFromMultipleNodeModulesDirectories.trace.json b/tests/baselines/reference/typeRootsFromMultipleNodeModulesDirectories.trace.json
index a541ee310ef7a..eec78e4019200 100644
--- a/tests/baselines/reference/typeRootsFromMultipleNodeModulesDirectories.trace.json
+++ b/tests/baselines/reference/typeRootsFromMultipleNodeModulesDirectories.trace.json
@@ -5,67 +5,74 @@
     "File '/foo/bar/node_modules/xyz.ts' does not exist.",
     "File '/foo/bar/node_modules/xyz.tsx' does not exist.",
     "File '/foo/bar/node_modules/xyz.d.ts' does not exist.",
-    "File '/foo/bar/node_modules/xyz.js' does not exist.",
-    "File '/foo/bar/node_modules/xyz.jsx' does not exist.",
     "File '/foo/bar/node_modules/xyz/package.json' does not exist.",
     "File '/foo/bar/node_modules/xyz/index.ts' does not exist.",
     "File '/foo/bar/node_modules/xyz/index.tsx' does not exist.",
     "File '/foo/bar/node_modules/xyz/index.d.ts' does not exist.",
-    "File '/foo/bar/node_modules/xyz/index.js' does not exist.",
-    "File '/foo/bar/node_modules/xyz/index.jsx' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz.ts' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz.tsx' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz.d.ts' does not exist.",
-    "File '/foo/bar/node_modules/@types/xyz.js' does not exist.",
-    "File '/foo/bar/node_modules/@types/xyz.jsx' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz/package.json' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz/index.ts' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz/index.tsx' does not exist.",
     "File '/foo/bar/node_modules/@types/xyz/index.d.ts' does not exist.",
-    "File '/foo/bar/node_modules/@types/xyz/index.js' does not exist.",
-    "File '/foo/bar/node_modules/@types/xyz/index.jsx' does not exist.",
     "File '/foo/node_modules/xyz.ts' does not exist.",
     "File '/foo/node_modules/xyz.tsx' does not exist.",
     "File '/foo/node_modules/xyz.d.ts' does not exist.",
-    "File '/foo/node_modules/xyz.js' does not exist.",
-    "File '/foo/node_modules/xyz.jsx' does not exist.",
     "File '/foo/node_modules/xyz/package.json' does not exist.",
     "File '/foo/node_modules/xyz/index.ts' does not exist.",
     "File '/foo/node_modules/xyz/index.tsx' does not exist.",
     "File '/foo/node_modules/xyz/index.d.ts' does not exist.",
-    "File '/foo/node_modules/xyz/index.js' does not exist.",
-    "File '/foo/node_modules/xyz/index.jsx' does not exist.",
     "File '/foo/node_modules/@types/xyz.ts' does not exist.",
     "File '/foo/node_modules/@types/xyz.tsx' does not exist.",
     "File '/foo/node_modules/@types/xyz.d.ts' does not exist.",
-    "File '/foo/node_modules/@types/xyz.js' does not exist.",
-    "File '/foo/node_modules/@types/xyz.jsx' does not exist.",
     "File '/foo/node_modules/@types/xyz/package.json' does not exist.",
     "File '/foo/node_modules/@types/xyz/index.ts' does not exist.",
     "File '/foo/node_modules/@types/xyz/index.tsx' does not exist.",
     "File '/foo/node_modules/@types/xyz/index.d.ts' does not exist.",
-    "File '/foo/node_modules/@types/xyz/index.js' does not exist.",
-    "File '/foo/node_modules/@types/xyz/index.jsx' does not exist.",
     "File '/node_modules/xyz.ts' does not exist.",
     "File '/node_modules/xyz.tsx' does not exist.",
     "File '/node_modules/xyz.d.ts' does not exist.",
-    "File '/node_modules/xyz.js' does not exist.",
-    "File '/node_modules/xyz.jsx' does not exist.",
     "File '/node_modules/xyz/package.json' does not exist.",
     "File '/node_modules/xyz/index.ts' does not exist.",
     "File '/node_modules/xyz/index.tsx' does not exist.",
     "File '/node_modules/xyz/index.d.ts' does not exist.",
-    "File '/node_modules/xyz/index.js' does not exist.",
-    "File '/node_modules/xyz/index.jsx' does not exist.",
     "File '/node_modules/@types/xyz.ts' does not exist.",
     "File '/node_modules/@types/xyz.tsx' does not exist.",
     "File '/node_modules/@types/xyz.d.ts' does not exist.",
-    "File '/node_modules/@types/xyz.js' does not exist.",
-    "File '/node_modules/@types/xyz.jsx' does not exist.",
     "File '/node_modules/@types/xyz/package.json' does not exist.",
     "File '/node_modules/@types/xyz/index.ts' does not exist.",
     "File '/node_modules/@types/xyz/index.tsx' does not exist.",
     "File '/node_modules/@types/xyz/index.d.ts' does not exist.",
+    "Loading module 'xyz' from 'node_modules' folder.",
+    "File '/foo/bar/node_modules/xyz.js' does not exist.",
+    "File '/foo/bar/node_modules/xyz.jsx' does not exist.",
+    "File '/foo/bar/node_modules/xyz/package.json' does not exist.",
+    "File '/foo/bar/node_modules/xyz/index.js' does not exist.",
+    "File '/foo/bar/node_modules/xyz/index.jsx' does not exist.",
+    "File '/foo/bar/node_modules/@types/xyz.js' does not exist.",
+    "File '/foo/bar/node_modules/@types/xyz.jsx' does not exist.",
+    "File '/foo/bar/node_modules/@types/xyz/package.json' does not exist.",
+    "File '/foo/bar/node_modules/@types/xyz/index.js' does not exist.",
+    "File '/foo/bar/node_modules/@types/xyz/index.jsx' does not exist.",
+    "File '/foo/node_modules/xyz.js' does not exist.",
+    "File '/foo/node_modules/xyz.jsx' does not exist.",
+    "File '/foo/node_modules/xyz/package.json' does not exist.",
+    "File '/foo/node_modules/xyz/index.js' does not exist.",
+    "File '/foo/node_modules/xyz/index.jsx' does not exist.",
+    "File '/foo/node_modules/@types/xyz.js' does not exist.",
+    "File '/foo/node_modules/@types/xyz.jsx' does not exist.",
+    "File '/foo/node_modules/@types/xyz/package.json' does not exist.",
+    "File '/foo/node_modules/@types/xyz/index.js' does not exist.",
+    "File '/foo/node_modules/@types/xyz/index.jsx' does not exist.",
+    "File '/node_modules/xyz.js' does not exist.",
+    "File '/node_modules/xyz.jsx' does not exist.",
+    "File '/node_modules/xyz/package.json' does not exist.",
+    "File '/node_modules/xyz/index.js' does not exist.",
+    "File '/node_modules/xyz/index.jsx' does not exist.",
+    "File '/node_modules/@types/xyz.js' does not exist.",
+    "File '/node_modules/@types/xyz.jsx' does not exist.",
+    "File '/node_modules/@types/xyz/package.json' does not exist.",
     "File '/node_modules/@types/xyz/index.js' does not exist.",
     "File '/node_modules/@types/xyz/index.jsx' does not exist.",
     "======== Module name 'xyz' was not resolved. ========",
@@ -75,67 +82,74 @@
     "File '/foo/bar/node_modules/pdq.ts' does not exist.",
     "File '/foo/bar/node_modules/pdq.tsx' does not exist.",
     "File '/foo/bar/node_modules/pdq.d.ts' does not exist.",
-    "File '/foo/bar/node_modules/pdq.js' does not exist.",
-    "File '/foo/bar/node_modules/pdq.jsx' does not exist.",
     "File '/foo/bar/node_modules/pdq/package.json' does not exist.",
     "File '/foo/bar/node_modules/pdq/index.ts' does not exist.",
     "File '/foo/bar/node_modules/pdq/index.tsx' does not exist.",
     "File '/foo/bar/node_modules/pdq/index.d.ts' does not exist.",
-    "File '/foo/bar/node_modules/pdq/index.js' does not exist.",
-    "File '/foo/bar/node_modules/pdq/index.jsx' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq.ts' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq.tsx' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq.d.ts' does not exist.",
-    "File '/foo/bar/node_modules/@types/pdq.js' does not exist.",
-    "File '/foo/bar/node_modules/@types/pdq.jsx' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq/package.json' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq/index.ts' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq/index.tsx' does not exist.",
     "File '/foo/bar/node_modules/@types/pdq/index.d.ts' does not exist.",
-    "File '/foo/bar/node_modules/@types/pdq/index.js' does not exist.",
-    "File '/foo/bar/node_modules/@types/pdq/index.jsx' does not exist.",
     "File '/foo/node_modules/pdq.ts' does not exist.",
     "File '/foo/node_modules/pdq.tsx' does not exist.",
     "File '/foo/node_modules/pdq.d.ts' does not exist.",
-    "File '/foo/node_modules/pdq.js' does not exist.",
-    "File '/foo/node_modules/pdq.jsx' does not exist.",
     "File '/foo/node_modules/pdq/package.json' does not exist.",
     "File '/foo/node_modules/pdq/index.ts' does not exist.",
     "File '/foo/node_modules/pdq/index.tsx' does not exist.",
     "File '/foo/node_modules/pdq/index.d.ts' does not exist.",
-    "File '/foo/node_modules/pdq/index.js' does not exist.",
-    "File '/foo/node_modules/pdq/index.jsx' does not exist.",
     "File '/foo/node_modules/@types/pdq.ts' does not exist.",
     "File '/foo/node_modules/@types/pdq.tsx' does not exist.",
     "File '/foo/node_modules/@types/pdq.d.ts' does not exist.",
-    "File '/foo/node_modules/@types/pdq.js' does not exist.",
-    "File '/foo/node_modules/@types/pdq.jsx' does not exist.",
     "File '/foo/node_modules/@types/pdq/package.json' does not exist.",
     "File '/foo/node_modules/@types/pdq/index.ts' does not exist.",
     "File '/foo/node_modules/@types/pdq/index.tsx' does not exist.",
     "File '/foo/node_modules/@types/pdq/index.d.ts' does not exist.",
-    "File '/foo/node_modules/@types/pdq/index.js' does not exist.",
-    "File '/foo/node_modules/@types/pdq/index.jsx' does not exist.",
     "File '/node_modules/pdq.ts' does not exist.",
     "File '/node_modules/pdq.tsx' does not exist.",
     "File '/node_modules/pdq.d.ts' does not exist.",
-    "File '/node_modules/pdq.js' does not exist.",
-    "File '/node_modules/pdq.jsx' does not exist.",
     "File '/node_modules/pdq/package.json' does not exist.",
     "File '/node_modules/pdq/index.ts' does not exist.",
     "File '/node_modules/pdq/index.tsx' does not exist.",
     "File '/node_modules/pdq/index.d.ts' does not exist.",
-    "File '/node_modules/pdq/index.js' does not exist.",
-    "File '/node_modules/pdq/index.jsx' does not exist.",
     "File '/node_modules/@types/pdq.ts' does not exist.",
     "File '/node_modules/@types/pdq.tsx' does not exist.",
     "File '/node_modules/@types/pdq.d.ts' does not exist.",
-    "File '/node_modules/@types/pdq.js' does not exist.",
-    "File '/node_modules/@types/pdq.jsx' does not exist.",
     "File '/node_modules/@types/pdq/package.json' does not exist.",
     "File '/node_modules/@types/pdq/index.ts' does not exist.",
     "File '/node_modules/@types/pdq/index.tsx' does not exist.",
     "File '/node_modules/@types/pdq/index.d.ts' does not exist.",
+    "Loading module 'pdq' from 'node_modules' folder.",
+    "File '/foo/bar/node_modules/pdq.js' does not exist.",
+    "File '/foo/bar/node_modules/pdq.jsx' does not exist.",
+    "File '/foo/bar/node_modules/pdq/package.json' does not exist.",
+    "File '/foo/bar/node_modules/pdq/index.js' does not exist.",
+    "File '/foo/bar/node_modules/pdq/index.jsx' does not exist.",
+    "File '/foo/bar/node_modules/@types/pdq.js' does not exist.",
+    "File '/foo/bar/node_modules/@types/pdq.jsx' does not exist.",
+    "File '/foo/bar/node_modules/@types/pdq/package.json' does not exist.",
+    "File '/foo/bar/node_modules/@types/pdq/index.js' does not exist.",
+    "File '/foo/bar/node_modules/@types/pdq/index.jsx' does not exist.",
+    "File '/foo/node_modules/pdq.js' does not exist.",
+    "File '/foo/node_modules/pdq.jsx' does not exist.",
+    "File '/foo/node_modules/pdq/package.json' does not exist.",
+    "File '/foo/node_modules/pdq/index.js' does not exist.",
+    "File '/foo/node_modules/pdq/index.jsx' does not exist.",
+    "File '/foo/node_modules/@types/pdq.js' does not exist.",
+    "File '/foo/node_modules/@types/pdq.jsx' does not exist.",
+    "File '/foo/node_modules/@types/pdq/package.json' does not exist.",
+    "File '/foo/node_modules/@types/pdq/index.js' does not exist.",
+    "File '/foo/node_modules/@types/pdq/index.jsx' does not exist.",
+    "File '/node_modules/pdq.js' does not exist.",
+    "File '/node_modules/pdq.jsx' does not exist.",
+    "File '/node_modules/pdq/package.json' does not exist.",
+    "File '/node_modules/pdq/index.js' does not exist.",
+    "File '/node_modules/pdq/index.jsx' does not exist.",
+    "File '/node_modules/@types/pdq.js' does not exist.",
+    "File '/node_modules/@types/pdq.jsx' does not exist.",
+    "File '/node_modules/@types/pdq/package.json' does not exist.",
     "File '/node_modules/@types/pdq/index.js' does not exist.",
     "File '/node_modules/@types/pdq/index.jsx' does not exist.",
     "======== Module name 'pdq' was not resolved. ========",
@@ -145,67 +159,74 @@
     "File '/foo/bar/node_modules/abc.ts' does not exist.",
     "File '/foo/bar/node_modules/abc.tsx' does not exist.",
     "File '/foo/bar/node_modules/abc.d.ts' does not exist.",
-    "File '/foo/bar/node_modules/abc.js' does not exist.",
-    "File '/foo/bar/node_modules/abc.jsx' does not exist.",
     "File '/foo/bar/node_modules/abc/package.json' does not exist.",
     "File '/foo/bar/node_modules/abc/index.ts' does not exist.",
     "File '/foo/bar/node_modules/abc/index.tsx' does not exist.",
     "File '/foo/bar/node_modules/abc/index.d.ts' does not exist.",
-    "File '/foo/bar/node_modules/abc/index.js' does not exist.",
-    "File '/foo/bar/node_modules/abc/index.jsx' does not exist.",
     "File '/foo/bar/node_modules/@types/abc.ts' does not exist.",
     "File '/foo/bar/node_modules/@types/abc.tsx' does not exist.",
     "File '/foo/bar/node_modules/@types/abc.d.ts' does not exist.",
-    "File '/foo/bar/node_modules/@types/abc.js' does not exist.",
-    "File '/foo/bar/node_modules/@types/abc.jsx' does not exist.",
     "File '/foo/bar/node_modules/@types/abc/package.json' does not exist.",
     "File '/foo/bar/node_modules/@types/abc/index.ts' does not exist.",
     "File '/foo/bar/node_modules/@types/abc/index.tsx' does not exist.",
     "File '/foo/bar/node_modules/@types/abc/index.d.ts' does not exist.",
-    "File '/foo/bar/node_modules/@types/abc/index.js' does not exist.",
-    "File '/foo/bar/node_modules/@types/abc/index.jsx' does not exist.",
     "File '/foo/node_modules/abc.ts' does not exist.",
     "File '/foo/node_modules/abc.tsx' does not exist.",
     "File '/foo/node_modules/abc.d.ts' does not exist.",
-    "File '/foo/node_modules/abc.js' does not exist.",
-    "File '/foo/node_modules/abc.jsx' does not exist.",
     "File '/foo/node_modules/abc/package.json' does not exist.",
     "File '/foo/node_modules/abc/index.ts' does not exist.",
     "File '/foo/node_modules/abc/index.tsx' does not exist.",
     "File '/foo/node_modules/abc/index.d.ts' does not exist.",
-    "File '/foo/node_modules/abc/index.js' does not exist.",
-    "File '/foo/node_modules/abc/index.jsx' does not exist.",
     "File '/foo/node_modules/@types/abc.ts' does not exist.",
     "File '/foo/node_modules/@types/abc.tsx' does not exist.",
     "File '/foo/node_modules/@types/abc.d.ts' does not exist.",
-    "File '/foo/node_modules/@types/abc.js' does not exist.",
-    "File '/foo/node_modules/@types/abc.jsx' does not exist.",
     "File '/foo/node_modules/@types/abc/package.json' does not exist.",
     "File '/foo/node_modules/@types/abc/index.ts' does not exist.",
     "File '/foo/node_modules/@types/abc/index.tsx' does not exist.",
     "File '/foo/node_modules/@types/abc/index.d.ts' does not exist.",
-    "File '/foo/node_modules/@types/abc/index.js' does not exist.",
-    "File '/foo/node_modules/@types/abc/index.jsx' does not exist.",
     "File '/node_modules/abc.ts' does not exist.",
     "File '/node_modules/abc.tsx' does not exist.",
     "File '/node_modules/abc.d.ts' does not exist.",
-    "File '/node_modules/abc.js' does not exist.",
-    "File '/node_modules/abc.jsx' does not exist.",
     "File '/node_modules/abc/package.json' does not exist.",
     "File '/node_modules/abc/index.ts' does not exist.",
     "File '/node_modules/abc/index.tsx' does not exist.",
     "File '/node_modules/abc/index.d.ts' does not exist.",
-    "File '/node_modules/abc/index.js' does not exist.",
-    "File '/node_modules/abc/index.jsx' does not exist.",
     "File '/node_modules/@types/abc.ts' does not exist.",
     "File '/node_modules/@types/abc.tsx' does not exist.",
     "File '/node_modules/@types/abc.d.ts' does not exist.",
-    "File '/node_modules/@types/abc.js' does not exist.",
-    "File '/node_modules/@types/abc.jsx' does not exist.",
     "File '/node_modules/@types/abc/package.json' does not exist.",
     "File '/node_modules/@types/abc/index.ts' does not exist.",
     "File '/node_modules/@types/abc/index.tsx' does not exist.",
     "File '/node_modules/@types/abc/index.d.ts' does not exist.",
+    "Loading module 'abc' from 'node_modules' folder.",
+    "File '/foo/bar/node_modules/abc.js' does not exist.",
+    "File '/foo/bar/node_modules/abc.jsx' does not exist.",
+    "File '/foo/bar/node_modules/abc/package.json' does not exist.",
+    "File '/foo/bar/node_modules/abc/index.js' does not exist.",
+    "File '/foo/bar/node_modules/abc/index.jsx' does not exist.",
+    "File '/foo/bar/node_modules/@types/abc.js' does not exist.",
+    "File '/foo/bar/node_modules/@types/abc.jsx' does not exist.",
+    "File '/foo/bar/node_modules/@types/abc/package.json' does not exist.",
+    "File '/foo/bar/node_modules/@types/abc/index.js' does not exist.",
+    "File '/foo/bar/node_modules/@types/abc/index.jsx' does not exist.",
+    "File '/foo/node_modules/abc.js' does not exist.",
+    "File '/foo/node_modules/abc.jsx' does not exist.",
+    "File '/foo/node_modules/abc/package.json' does not exist.",
+    "File '/foo/node_modules/abc/index.js' does not exist.",
+    "File '/foo/node_modules/abc/index.jsx' does not exist.",
+    "File '/foo/node_modules/@types/abc.js' does not exist.",
+    "File '/foo/node_modules/@types/abc.jsx' does not exist.",
+    "File '/foo/node_modules/@types/abc/package.json' does not exist.",
+    "File '/foo/node_modules/@types/abc/index.js' does not exist.",
+    "File '/foo/node_modules/@types/abc/index.jsx' does not exist.",
+    "File '/node_modules/abc.js' does not exist.",
+    "File '/node_modules/abc.jsx' does not exist.",
+    "File '/node_modules/abc/package.json' does not exist.",
+    "File '/node_modules/abc/index.js' does not exist.",
+    "File '/node_modules/abc/index.jsx' does not exist.",
+    "File '/node_modules/@types/abc.js' does not exist.",
+    "File '/node_modules/@types/abc.jsx' does not exist.",
+    "File '/node_modules/@types/abc/package.json' does not exist.",
     "File '/node_modules/@types/abc/index.js' does not exist.",
     "File '/node_modules/@types/abc/index.jsx' does not exist.",
     "======== Module name 'abc' was not resolved. ========",
diff --git a/tests/baselines/reference/typeRootsFromNodeModulesInParentDirectory.trace.json b/tests/baselines/reference/typeRootsFromNodeModulesInParentDirectory.trace.json
index 12a0bc0d23ab9..4bb62bc255a0e 100644
--- a/tests/baselines/reference/typeRootsFromNodeModulesInParentDirectory.trace.json
+++ b/tests/baselines/reference/typeRootsFromNodeModulesInParentDirectory.trace.json
@@ -5,45 +5,50 @@
     "File '/src/node_modules/xyz.ts' does not exist.",
     "File '/src/node_modules/xyz.tsx' does not exist.",
     "File '/src/node_modules/xyz.d.ts' does not exist.",
-    "File '/src/node_modules/xyz.js' does not exist.",
-    "File '/src/node_modules/xyz.jsx' does not exist.",
     "File '/src/node_modules/xyz/package.json' does not exist.",
     "File '/src/node_modules/xyz/index.ts' does not exist.",
     "File '/src/node_modules/xyz/index.tsx' does not exist.",
     "File '/src/node_modules/xyz/index.d.ts' does not exist.",
-    "File '/src/node_modules/xyz/index.js' does not exist.",
-    "File '/src/node_modules/xyz/index.jsx' does not exist.",
     "File '/src/node_modules/@types/xyz.ts' does not exist.",
     "File '/src/node_modules/@types/xyz.tsx' does not exist.",
     "File '/src/node_modules/@types/xyz.d.ts' does not exist.",
-    "File '/src/node_modules/@types/xyz.js' does not exist.",
-    "File '/src/node_modules/@types/xyz.jsx' does not exist.",
     "File '/src/node_modules/@types/xyz/package.json' does not exist.",
     "File '/src/node_modules/@types/xyz/index.ts' does not exist.",
     "File '/src/node_modules/@types/xyz/index.tsx' does not exist.",
     "File '/src/node_modules/@types/xyz/index.d.ts' does not exist.",
-    "File '/src/node_modules/@types/xyz/index.js' does not exist.",
-    "File '/src/node_modules/@types/xyz/index.jsx' does not exist.",
     "File '/node_modules/xyz.ts' does not exist.",
     "File '/node_modules/xyz.tsx' does not exist.",
     "File '/node_modules/xyz.d.ts' does not exist.",
-    "File '/node_modules/xyz.js' does not exist.",
-    "File '/node_modules/xyz.jsx' does not exist.",
     "File '/node_modules/xyz/package.json' does not exist.",
     "File '/node_modules/xyz/index.ts' does not exist.",
     "File '/node_modules/xyz/index.tsx' does not exist.",
     "File '/node_modules/xyz/index.d.ts' does not exist.",
-    "File '/node_modules/xyz/index.js' does not exist.",
-    "File '/node_modules/xyz/index.jsx' does not exist.",
     "File '/node_modules/@types/xyz.ts' does not exist.",
     "File '/node_modules/@types/xyz.tsx' does not exist.",
     "File '/node_modules/@types/xyz.d.ts' does not exist.",
-    "File '/node_modules/@types/xyz.js' does not exist.",
-    "File '/node_modules/@types/xyz.jsx' does not exist.",
     "File '/node_modules/@types/xyz/package.json' does not exist.",
     "File '/node_modules/@types/xyz/index.ts' does not exist.",
     "File '/node_modules/@types/xyz/index.tsx' does not exist.",
     "File '/node_modules/@types/xyz/index.d.ts' does not exist.",
+    "Loading module 'xyz' from 'node_modules' folder.",
+    "File '/src/node_modules/xyz.js' does not exist.",
+    "File '/src/node_modules/xyz.jsx' does not exist.",
+    "File '/src/node_modules/xyz/package.json' does not exist.",
+    "File '/src/node_modules/xyz/index.js' does not exist.",
+    "File '/src/node_modules/xyz/index.jsx' does not exist.",
+    "File '/src/node_modules/@types/xyz.js' does not exist.",
+    "File '/src/node_modules/@types/xyz.jsx' does not exist.",
+    "File '/src/node_modules/@types/xyz/package.json' does not exist.",
+    "File '/src/node_modules/@types/xyz/index.js' does not exist.",
+    "File '/src/node_modules/@types/xyz/index.jsx' does not exist.",
+    "File '/node_modules/xyz.js' does not exist.",
+    "File '/node_modules/xyz.jsx' does not exist.",
+    "File '/node_modules/xyz/package.json' does not exist.",
+    "File '/node_modules/xyz/index.js' does not exist.",
+    "File '/node_modules/xyz/index.jsx' does not exist.",
+    "File '/node_modules/@types/xyz.js' does not exist.",
+    "File '/node_modules/@types/xyz.jsx' does not exist.",
+    "File '/node_modules/@types/xyz/package.json' does not exist.",
     "File '/node_modules/@types/xyz/index.js' does not exist.",
     "File '/node_modules/@types/xyz/index.jsx' does not exist.",
     "======== Module name 'xyz' was not resolved. ========",
diff --git a/tests/baselines/reference/typingsLookup4.trace.json b/tests/baselines/reference/typingsLookup4.trace.json
index e5ad33fd0d2d4..bb9d94f43b510 100644
--- a/tests/baselines/reference/typingsLookup4.trace.json
+++ b/tests/baselines/reference/typingsLookup4.trace.json
@@ -5,19 +5,13 @@
     "File '/node_modules/jquery.ts' does not exist.",
     "File '/node_modules/jquery.tsx' does not exist.",
     "File '/node_modules/jquery.d.ts' does not exist.",
-    "File '/node_modules/jquery.js' does not exist.",
-    "File '/node_modules/jquery.jsx' does not exist.",
     "File '/node_modules/jquery/package.json' does not exist.",
     "File '/node_modules/jquery/index.ts' does not exist.",
     "File '/node_modules/jquery/index.tsx' does not exist.",
     "File '/node_modules/jquery/index.d.ts' does not exist.",
-    "File '/node_modules/jquery/index.js' does not exist.",
-    "File '/node_modules/jquery/index.jsx' does not exist.",
     "File '/node_modules/@types/jquery.ts' does not exist.",
     "File '/node_modules/@types/jquery.tsx' does not exist.",
     "File '/node_modules/@types/jquery.d.ts' does not exist.",
-    "File '/node_modules/@types/jquery.js' does not exist.",
-    "File '/node_modules/@types/jquery.jsx' does not exist.",
     "Found 'package.json' at '/node_modules/@types/jquery/package.json'.",
     "'package.json' has 'typings' field 'jquery.d.ts' that references '/node_modules/@types/jquery/jquery.d.ts'.",
     "File '/node_modules/@types/jquery/jquery.d.ts' exist - use it as a name resolution result.",
@@ -29,19 +23,13 @@
     "File '/node_modules/kquery.ts' does not exist.",
     "File '/node_modules/kquery.tsx' does not exist.",
     "File '/node_modules/kquery.d.ts' does not exist.",
-    "File '/node_modules/kquery.js' does not exist.",
-    "File '/node_modules/kquery.jsx' does not exist.",
     "File '/node_modules/kquery/package.json' does not exist.",
     "File '/node_modules/kquery/index.ts' does not exist.",
     "File '/node_modules/kquery/index.tsx' does not exist.",
     "File '/node_modules/kquery/index.d.ts' does not exist.",
-    "File '/node_modules/kquery/index.js' does not exist.",
-    "File '/node_modules/kquery/index.jsx' does not exist.",
     "File '/node_modules/@types/kquery.ts' does not exist.",
     "File '/node_modules/@types/kquery.tsx' does not exist.",
     "File '/node_modules/@types/kquery.d.ts' does not exist.",
-    "File '/node_modules/@types/kquery.js' does not exist.",
-    "File '/node_modules/@types/kquery.jsx' does not exist.",
     "Found 'package.json' at '/node_modules/@types/kquery/package.json'.",
     "'package.json' has 'typings' field 'kquery' that references '/node_modules/@types/kquery/kquery'.",
     "File '/node_modules/@types/kquery/kquery' does not exist.",
@@ -56,19 +44,13 @@
     "File '/node_modules/lquery.ts' does not exist.",
     "File '/node_modules/lquery.tsx' does not exist.",
     "File '/node_modules/lquery.d.ts' does not exist.",
-    "File '/node_modules/lquery.js' does not exist.",
-    "File '/node_modules/lquery.jsx' does not exist.",
     "File '/node_modules/lquery/package.json' does not exist.",
     "File '/node_modules/lquery/index.ts' does not exist.",
     "File '/node_modules/lquery/index.tsx' does not exist.",
     "File '/node_modules/lquery/index.d.ts' does not exist.",
-    "File '/node_modules/lquery/index.js' does not exist.",
-    "File '/node_modules/lquery/index.jsx' does not exist.",
     "File '/node_modules/@types/lquery.ts' does not exist.",
     "File '/node_modules/@types/lquery.tsx' does not exist.",
     "File '/node_modules/@types/lquery.d.ts' does not exist.",
-    "File '/node_modules/@types/lquery.js' does not exist.",
-    "File '/node_modules/@types/lquery.jsx' does not exist.",
     "Found 'package.json' at '/node_modules/@types/lquery/package.json'.",
     "'package.json' has 'typings' field 'lquery' that references '/node_modules/@types/lquery/lquery'.",
     "File '/node_modules/@types/lquery/lquery' does not exist.",
diff --git a/tests/baselines/reference/typingsLookupAmd.trace.json b/tests/baselines/reference/typingsLookupAmd.trace.json
index 732e990065841..496166926a804 100644
--- a/tests/baselines/reference/typingsLookupAmd.trace.json
+++ b/tests/baselines/reference/typingsLookupAmd.trace.json
@@ -4,34 +4,22 @@
     "File '/x/y/b.ts' does not exist.",
     "File '/x/y/b.tsx' does not exist.",
     "File '/x/y/b.d.ts' does not exist.",
-    "File '/x/y/b.js' does not exist.",
-    "File '/x/y/b.jsx' does not exist.",
     "File '/x/b.ts' does not exist.",
     "File '/x/b.tsx' does not exist.",
     "File '/x/b.d.ts' does not exist.",
-    "File '/x/b.js' does not exist.",
-    "File '/x/b.jsx' does not exist.",
     "File '/b.ts' does not exist.",
     "File '/b.tsx' does not exist.",
     "File '/b.d.ts' does not exist.",
-    "File '/b.js' does not exist.",
-    "File '/b.jsx' does not exist.",
     "File '/x/y/node_modules/@types/b.ts' does not exist.",
     "File '/x/y/node_modules/@types/b.tsx' does not exist.",
     "File '/x/y/node_modules/@types/b.d.ts' does not exist.",
-    "File '/x/y/node_modules/@types/b.js' does not exist.",
-    "File '/x/y/node_modules/@types/b.jsx' does not exist.",
     "File '/x/y/node_modules/@types/b/package.json' does not exist.",
     "File '/x/y/node_modules/@types/b/index.ts' does not exist.",
     "File '/x/y/node_modules/@types/b/index.tsx' does not exist.",
     "File '/x/y/node_modules/@types/b/index.d.ts' does not exist.",
-    "File '/x/y/node_modules/@types/b/index.js' does not exist.",
-    "File '/x/y/node_modules/@types/b/index.jsx' does not exist.",
     "File '/x/node_modules/@types/b.ts' does not exist.",
     "File '/x/node_modules/@types/b.tsx' does not exist.",
     "File '/x/node_modules/@types/b.d.ts' does not exist.",
-    "File '/x/node_modules/@types/b.js' does not exist.",
-    "File '/x/node_modules/@types/b.jsx' does not exist.",
     "File '/x/node_modules/@types/b/package.json' does not exist.",
     "File '/x/node_modules/@types/b/index.ts' does not exist.",
     "File '/x/node_modules/@types/b/index.tsx' does not exist.",
@@ -42,66 +30,42 @@
     "File '/x/node_modules/@types/b/a.ts' does not exist.",
     "File '/x/node_modules/@types/b/a.tsx' does not exist.",
     "File '/x/node_modules/@types/b/a.d.ts' does not exist.",
-    "File '/x/node_modules/@types/b/a.js' does not exist.",
-    "File '/x/node_modules/@types/b/a.jsx' does not exist.",
     "File '/x/node_modules/@types/a.ts' does not exist.",
     "File '/x/node_modules/@types/a.tsx' does not exist.",
     "File '/x/node_modules/@types/a.d.ts' does not exist.",
-    "File '/x/node_modules/@types/a.js' does not exist.",
-    "File '/x/node_modules/@types/a.jsx' does not exist.",
     "File '/x/node_modules/a.ts' does not exist.",
     "File '/x/node_modules/a.tsx' does not exist.",
     "File '/x/node_modules/a.d.ts' does not exist.",
-    "File '/x/node_modules/a.js' does not exist.",
-    "File '/x/node_modules/a.jsx' does not exist.",
     "File '/x/a.ts' does not exist.",
     "File '/x/a.tsx' does not exist.",
     "File '/x/a.d.ts' does not exist.",
-    "File '/x/a.js' does not exist.",
-    "File '/x/a.jsx' does not exist.",
     "File '/a.ts' does not exist.",
     "File '/a.tsx' does not exist.",
     "File '/a.d.ts' does not exist.",
-    "File '/a.js' does not exist.",
-    "File '/a.jsx' does not exist.",
     "File '/x/node_modules/@types/b/node_modules/@types/a.ts' does not exist.",
     "File '/x/node_modules/@types/b/node_modules/@types/a.tsx' does not exist.",
     "File '/x/node_modules/@types/b/node_modules/@types/a.d.ts' does not exist.",
-    "File '/x/node_modules/@types/b/node_modules/@types/a.js' does not exist.",
-    "File '/x/node_modules/@types/b/node_modules/@types/a.jsx' does not exist.",
     "File '/x/node_modules/@types/b/node_modules/@types/a/package.json' does not exist.",
     "File '/x/node_modules/@types/b/node_modules/@types/a/index.ts' does not exist.",
     "File '/x/node_modules/@types/b/node_modules/@types/a/index.tsx' does not exist.",
     "File '/x/node_modules/@types/b/node_modules/@types/a/index.d.ts' does not exist.",
-    "File '/x/node_modules/@types/b/node_modules/@types/a/index.js' does not exist.",
-    "File '/x/node_modules/@types/b/node_modules/@types/a/index.jsx' does not exist.",
     "File '/x/node_modules/@types/node_modules/@types/a.ts' does not exist.",
     "File '/x/node_modules/@types/node_modules/@types/a.tsx' does not exist.",
     "File '/x/node_modules/@types/node_modules/@types/a.d.ts' does not exist.",
-    "File '/x/node_modules/@types/node_modules/@types/a.js' does not exist.",
-    "File '/x/node_modules/@types/node_modules/@types/a.jsx' does not exist.",
     "File '/x/node_modules/@types/node_modules/@types/a/package.json' does not exist.",
     "File '/x/node_modules/@types/node_modules/@types/a/index.ts' does not exist.",
     "File '/x/node_modules/@types/node_modules/@types/a/index.tsx' does not exist.",
     "File '/x/node_modules/@types/node_modules/@types/a/index.d.ts' does not exist.",
-    "File '/x/node_modules/@types/node_modules/@types/a/index.js' does not exist.",
-    "File '/x/node_modules/@types/node_modules/@types/a/index.jsx' does not exist.",
     "File '/x/node_modules/@types/a.ts' does not exist.",
     "File '/x/node_modules/@types/a.tsx' does not exist.",
     "File '/x/node_modules/@types/a.d.ts' does not exist.",
-    "File '/x/node_modules/@types/a.js' does not exist.",
-    "File '/x/node_modules/@types/a.jsx' does not exist.",
     "File '/x/node_modules/@types/a/package.json' does not exist.",
     "File '/x/node_modules/@types/a/index.ts' does not exist.",
     "File '/x/node_modules/@types/a/index.tsx' does not exist.",
     "File '/x/node_modules/@types/a/index.d.ts' does not exist.",
-    "File '/x/node_modules/@types/a/index.js' does not exist.",
-    "File '/x/node_modules/@types/a/index.jsx' does not exist.",
     "File '/node_modules/@types/a.ts' does not exist.",
     "File '/node_modules/@types/a.tsx' does not exist.",
     "File '/node_modules/@types/a.d.ts' does not exist.",
-    "File '/node_modules/@types/a.js' does not exist.",
-    "File '/node_modules/@types/a.jsx' does not exist.",
     "File '/node_modules/@types/a/package.json' does not exist.",
     "File '/node_modules/@types/a/index.ts' does not exist.",
     "File '/node_modules/@types/a/index.tsx' does not exist.",

From 8ad68adac956eafa865b78c9c45cae1958c963cd Mon Sep 17 00:00:00 2001
From: Alexander Rusakov <a_s_rusakov@mail.ru>
Date: Wed, 26 Oct 2016 20:01:23 +0300
Subject: [PATCH 088/224] Fix #10108 (Completion suggestion for object literal
 with getter) (#11808)

* Fix #10108 (Completion suggestion for object literal with getter)

* completions for setter
---
 src/services/completions.ts                   |  4 +++-
 tests/cases/fourslash/server/completions03.ts | 20 +++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 tests/cases/fourslash/server/completions03.ts

diff --git a/src/services/completions.ts b/src/services/completions.ts
index ba5d150307519..b710aa8cd78bb 100644
--- a/src/services/completions.ts
+++ b/src/services/completions.ts
@@ -1590,7 +1590,9 @@ namespace ts.Completions {
                 if (m.kind !== SyntaxKind.PropertyAssignment &&
                     m.kind !== SyntaxKind.ShorthandPropertyAssignment &&
                     m.kind !== SyntaxKind.BindingElement &&
-                    m.kind !== SyntaxKind.MethodDeclaration) {
+                    m.kind !== SyntaxKind.MethodDeclaration &&
+                    m.kind !== SyntaxKind.GetAccessor &&
+                    m.kind !== SyntaxKind.SetAccessor) {
                     continue;
                 }
 
diff --git a/tests/cases/fourslash/server/completions03.ts b/tests/cases/fourslash/server/completions03.ts
new file mode 100644
index 0000000000000..ef5f165195126
--- /dev/null
+++ b/tests/cases/fourslash/server/completions03.ts
@@ -0,0 +1,20 @@
+/// <reference path="../fourslash.ts"/>
+
+// issue: https://github.com/Microsoft/TypeScript/issues/10108
+
+//// interface Foo {
+////    one: any;
+////    two: any;
+////    three: any;
+//// }
+////
+//// let x: Foo = {
+////     get one() { return "" },
+////     set two(t) {},
+////     /**/
+//// }
+
+goTo.marker("");
+verify.completionListContains("three");
+verify.not.completionListContains("one");
+verify.not.completionListContains("two");

From 718d57ff3c0f2dc20cc30bed8dee271b6813801e Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Wed, 26 Oct 2016 10:13:34 -0700
Subject: [PATCH 089/224] Move helper functions to core (fix build)

---
 src/compiler/core.ts      | 29 +++++++++++++++++++++++++++++
 src/compiler/utilities.ts | 29 -----------------------------
 2 files changed, 29 insertions(+), 29 deletions(-)

diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index ff32f48e65ed1..001401a8a965a 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -2094,4 +2094,33 @@ namespace ts {
         //  pos === undefined || pos === null || isNaN(pos) || pos < 0;
         return !(pos >= 0);
     }
+
+    /** True if an extension is one of the supported TypeScript extensions. */
+    export function extensionIsTypeScript(ext: Extension): boolean {
+        return ext <= Extension.LastTypeScriptExtension;
+    }
+
+    /**
+     * Gets the extension from a path.
+     * Path must have a valid extension.
+     */
+    export function extensionFromPath(path: string): Extension {
+        if (fileExtensionIs(path, ".d.ts")) {
+            return Extension.Dts;
+        }
+        if (fileExtensionIs(path, ".ts")) {
+            return Extension.Ts;
+        }
+        if (fileExtensionIs(path, ".tsx")) {
+            return Extension.Tsx;
+        }
+        if (fileExtensionIs(path, ".js")) {
+            return Extension.Js;
+        }
+        if (fileExtensionIs(path, ".jsx")) {
+            return Extension.Jsx;
+        }
+        Debug.fail(`File ${path} has unknown extension.`);
+        return Extension.Js;
+    }
 }
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index a29007edc014e..5f7c91b3b1c9e 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -118,35 +118,6 @@ namespace ts {
             oldResolution.resolvedFileName === newResolution.resolvedFileName;
     }
 
-    /** True if an extension is one of the supported TypeScript extensions. */
-    export function extensionIsTypeScript(ext: Extension): boolean {
-        return ext <= Extension.LastTypeScriptExtension;
-    }
-
-    /**
-     * Gets the extension from a path.
-     * Path must have a valid extension.
-     */
-    export function extensionFromPath(path: string): Extension {
-        if (fileExtensionIs(path, ".d.ts")) {
-            return Extension.Dts;
-        }
-        if (fileExtensionIs(path, ".ts")) {
-            return Extension.Ts;
-        }
-        if (fileExtensionIs(path, ".tsx")) {
-            return Extension.Tsx;
-        }
-        if (fileExtensionIs(path, ".js")) {
-            return Extension.Js;
-        }
-        if (fileExtensionIs(path, ".jsx")) {
-            return Extension.Jsx;
-        }
-        Debug.fail(`File ${path} has unknown extension.`);
-        return Extension.Js;
-    }
-
     /* @internal */
     export function typeDirectiveIsEqualTo(oldResolution: ResolvedTypeReferenceDirective, newResolution: ResolvedTypeReferenceDirective): boolean {
         return oldResolution.resolvedFileName === newResolution.resolvedFileName && oldResolution.primary === newResolution.primary;

From e7cfbfe185010cb7287c0bc33efd4a8f1b34145e Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Wed, 26 Oct 2016 13:39:12 -0700
Subject: [PATCH 090/224] Support parametric property access expressions + some
 renaming

---
 src/compiler/binder.ts             |  2 +-
 src/compiler/checker.ts            | 90 +++++++++++++++++-------------
 src/compiler/declarationEmitter.ts |  8 +--
 src/compiler/emitter.ts            |  8 +--
 src/compiler/parser.ts             | 10 ++--
 src/compiler/transformers/ts.ts    |  4 +-
 src/compiler/types.ts              | 26 ++++-----
 7 files changed, 80 insertions(+), 68 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 5318595aecae7..c05d0135f1448 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -3067,7 +3067,7 @@ namespace ts {
             case SyntaxKind.TypeAliasDeclaration:
             case SyntaxKind.ThisType:
             case SyntaxKind.TypeOperator:
-            case SyntaxKind.PropertyAccessType:
+            case SyntaxKind.IndexedAccessType:
             case SyntaxKind.LiteralType:
                 // Types and signatures are TypeScript syntax, and exclude all other facts.
                 transformFlags = TransformFlags.AssertTypeScript;
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 0f18c795ae396..0d23fbb44a5ce 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2219,15 +2219,15 @@ namespace ts {
                     else if (type.flags & TypeFlags.StringOrNumberLiteral) {
                         writer.writeStringLiteral(literalTypeToString(<LiteralType>type));
                     }
-                    else if (type.flags & TypeFlags.PropertyName) {
+                    else if (type.flags & TypeFlags.Index) {
                         writer.writeKeyword("keyof");
                         writeSpace(writer);
-                        writeType((<PropertyNameType>type).type, TypeFormatFlags.InElementType);
+                        writeType((<IndexType>type).type, TypeFormatFlags.InElementType);
                     }
-                    else if (type.flags & TypeFlags.PropertyAccess) {
-                        writeType((<PropertyAccessType>type).objectType, TypeFormatFlags.InElementType);
+                    else if (type.flags & TypeFlags.IndexedAccess) {
+                        writeType((<IndexedAccessType>type).objectType, TypeFormatFlags.InElementType);
                         writePunctuation(writer, SyntaxKind.OpenBracketToken);
-                        writeType((<PropertyAccessType>type).keyType, TypeFormatFlags.None);
+                        writeType((<IndexedAccessType>type).indexType, TypeFormatFlags.None);
                         writePunctuation(writer, SyntaxKind.CloseBracketToken);
                     }
                     else {
@@ -5678,43 +5678,43 @@ namespace ts {
             return startsWith(prop.name, "__@") ? neverType : getLiteralTypeForText(TypeFlags.StringLiteral, unescapeIdentifier(prop.name));
         }
 
-        function getPropertyNameTypeForTypeParameter(type: TypeParameter) {
-            if (!type.resolvedPropertyNameType) {
-                type.resolvedPropertyNameType = <PropertyNameType>createType(TypeFlags.PropertyName);
-                type.resolvedPropertyNameType.type = type;
+        function getIndexTypeForTypeParameter(type: TypeParameter) {
+            if (!type.resolvedIndexType) {
+                type.resolvedIndexType = <IndexType>createType(TypeFlags.Index);
+                type.resolvedIndexType.type = type;
             }
-            return type.resolvedPropertyNameType;
+            return type.resolvedIndexType;
         }
 
-        function getPropertyNameType(type: Type): Type {
+        function getIndexType(type: Type): Type {
             return type.flags & TypeFlags.TypeParameter ?
-                getPropertyNameTypeForTypeParameter(<TypeParameter>type) :
+                getIndexTypeForTypeParameter(<TypeParameter>type) :
                 getUnionType(map(getPropertiesOfType(type), getLiteralTypeFromPropertyName));
         }
 
         function getTypeFromTypeOperatorNode(node: TypeOperatorNode) {
             const links = getNodeLinks(node);
             if (!links.resolvedType) {
-                links.resolvedType = getPropertyNameType(getTypeFromTypeNodeNoAlias(node.type));
+                links.resolvedType = getIndexType(getTypeFromTypeNodeNoAlias(node.type));
             }
             return links.resolvedType;
         }
 
-        function createPropertyAccessType(objectType: Type, keyType: TypeParameter) {
-            const type = <PropertyAccessType>createType(TypeFlags.PropertyAccess);
+        function createIndexedAccessType(objectType: Type, keyType: TypeParameter) {
+            const type = <IndexedAccessType>createType(TypeFlags.IndexedAccess);
             type.objectType = objectType;
-            type.keyType = keyType;
+            type.indexType = keyType;
             return type;
         }
 
-        function getPropertyAccessTypeForTypeParameter(objectType: Type, keyType: TypeParameter) {
-            const propertyAccessTypes = keyType.resolvedPropertyAccessTypes || (keyType.resolvedPropertyAccessTypes = []);
-            return propertyAccessTypes[objectType.id] || (propertyAccessTypes[objectType.id] = createPropertyAccessType(objectType, keyType));
+        function getIndexedAccessTypeForTypeParameter(objectType: Type, keyType: TypeParameter) {
+            const indexedAccessTypes = keyType.resolvedIndexedAccessTypes || (keyType.resolvedIndexedAccessTypes = []);
+            return indexedAccessTypes[objectType.id] || (indexedAccessTypes[objectType.id] = createIndexedAccessType(objectType, keyType));
         }
 
-        function getPropertyAccessType(objectType: Type, keyType: Type) {
+        function getIndexedAccessType(objectType: Type, keyType: Type) {
             if (keyType.flags & TypeFlags.TypeParameter) {
-                return getPropertyAccessTypeForTypeParameter(objectType, <TypeParameter>keyType);
+                return getIndexedAccessTypeForTypeParameter(objectType, <TypeParameter>keyType);
             }
             if (isTypeOfKind(keyType, TypeFlags.StringLiteral) && !(keyType.flags & TypeFlags.Intersection)) {
                 return mapType(keyType, t => getTypeOfPropertyOfType(objectType, escapeIdentifier((<LiteralType>t).text)) || unknownType);
@@ -5722,29 +5722,29 @@ namespace ts {
             return keyType.flags & TypeFlags.Any ? anyType : unknownType;
         }
 
-        function resolvePropertyAccessTypeNode(node: PropertyAccessTypeNode) {
+        function resolveIndexedAccessTypeNode(node: IndexedAccessTypeNode) {
             const objectType = getTypeFromTypeNodeNoAlias(node.objectType);
-            const keyType = getTypeFromTypeNodeNoAlias(node.keyType);
+            const keyType = getTypeFromTypeNodeNoAlias(node.indexType);
             if (keyType.flags & TypeFlags.TypeParameter &&
-                getConstraintOfTypeParameter(<TypeParameter>keyType) === getPropertyNameType(objectType)) {
-                return getPropertyAccessType(objectType, keyType);
+                getConstraintOfTypeParameter(<TypeParameter>keyType) === getIndexType(objectType)) {
+                return getIndexedAccessType(objectType, keyType);
             }
             if (isTypeOfKind(keyType, TypeFlags.StringLiteral) && !(keyType.flags & TypeFlags.Intersection)) {
                 const missing = forEachType(keyType, t => getTypeOfPropertyOfType(objectType, escapeIdentifier((<LiteralType>t).text)) ? undefined : (<LiteralType>t).text);
                 if (missing) {
-                    error(node.keyType, Diagnostics.Property_0_is_missing_in_type_1, missing, typeToString(objectType));
+                    error(node.indexType, Diagnostics.Property_0_is_missing_in_type_1, missing, typeToString(objectType));
                     return unknownType;
                 }
-                return getPropertyAccessType(objectType, keyType);
+                return getIndexedAccessType(objectType, keyType);
             }
-            error(node.keyType, Diagnostics.Property_access_element_type_must_be_a_string_literal_type_or_a_type_parameter_constrained_to_keyof_0, typeToString(objectType));
+            error(node.indexType, Diagnostics.Property_access_element_type_must_be_a_string_literal_type_or_a_type_parameter_constrained_to_keyof_0, typeToString(objectType));
             return unknownType;
         }
 
-        function getTypeFromPropertyAccessTypeNode(node: PropertyAccessTypeNode) {
+        function getTypeFromIndexedAccessTypeNode(node: IndexedAccessTypeNode) {
             const links = getNodeLinks(node);
             if (!links.resolvedType) {
-                links.resolvedType = resolvePropertyAccessTypeNode(node);
+                links.resolvedType = resolveIndexedAccessTypeNode(node);
             }
             return links.resolvedType;
         }
@@ -5910,8 +5910,8 @@ namespace ts {
                     return getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node, aliasSymbol, aliasTypeArguments);
                 case SyntaxKind.TypeOperator:
                     return getTypeFromTypeOperatorNode(<TypeOperatorNode>node);
-                case SyntaxKind.PropertyAccessType:
-                    return getTypeFromPropertyAccessTypeNode(<PropertyAccessTypeNode>node);
+                case SyntaxKind.IndexedAccessType:
+                    return getTypeFromIndexedAccessTypeNode(<IndexedAccessTypeNode>node);
                 // This function assumes that an identifier or qualified name is a type expression
                 // Callers should first ensure this by calling isTypeNode
                 case SyntaxKind.Identifier:
@@ -6173,11 +6173,11 @@ namespace ts {
                 if (type.flags & TypeFlags.Intersection) {
                     return getIntersectionType(instantiateList((<IntersectionType>type).types, mapper, instantiateType), type.aliasSymbol, mapper.targetTypes);
                 }
-                if (type.flags & TypeFlags.PropertyName) {
-                    return getPropertyNameType(instantiateType((<PropertyNameType>type).type, mapper));
+                if (type.flags & TypeFlags.Index) {
+                    return getIndexType(instantiateType((<IndexType>type).type, mapper));
                 }
-                if (type.flags & TypeFlags.PropertyAccess) {
-                    return getPropertyAccessType(instantiateType((<PropertyAccessType>type).objectType, mapper), instantiateType((<PropertyAccessType>type).keyType, mapper));
+                if (type.flags & TypeFlags.IndexedAccess) {
+                    return getIndexedAccessType(instantiateType((<IndexedAccessType>type).objectType, mapper), instantiateType((<IndexedAccessType>type).indexType, mapper));
                 }
             }
             return type;
@@ -8114,7 +8114,7 @@ namespace ts {
 
         function hasPrimitiveConstraint(type: TypeParameter): boolean {
             const constraint = getConstraintOfTypeParameter(type);
-            return constraint && maybeTypeOfKind(constraint, TypeFlags.Primitive | TypeFlags.PropertyName);
+            return constraint && maybeTypeOfKind(constraint, TypeFlags.Primitive | TypeFlags.Index);
         }
 
         function getInferredType(context: InferenceContext, index: number): Type {
@@ -11520,14 +11520,20 @@ namespace ts {
                 }
             }
 
-            // Obtain base constraint such that we can bail out if the constraint is an unknown type
-            const objectType = getApparentType(checkNonNullExpression(node.expression));
+            let objectType = checkNonNullExpression(node.expression);
             const indexType = node.argumentExpression ? checkExpression(node.argumentExpression) : unknownType;
 
             if (objectType === unknownType || objectType === silentNeverType) {
                 return objectType;
             }
 
+            if (indexType.flags & TypeFlags.TypeParameter &&
+                isTypeAssignableTo(getConstraintOfTypeParameter(<TypeParameter>indexType), getIndexType(objectType))) {
+                return getIndexedAccessType(objectType, indexType);
+            }
+
+            objectType = getApparentType(objectType);
+
             const isConstEnum = isConstEnumObjectType(objectType);
             if (isConstEnum &&
                 (!node.argumentExpression || node.argumentExpression.kind !== SyntaxKind.StringLiteral)) {
@@ -15043,6 +15049,10 @@ namespace ts {
             forEach(node.types, checkSourceElement);
         }
 
+        function checkIndexedAccessType(node: IndexedAccessTypeNode) {
+            getTypeFromIndexedAccessTypeNode(node);
+        }
+
         function isPrivateWithinAmbient(node: Node): boolean {
             return (getModifierFlags(node) & ModifierFlags.Private) && isInAmbientContext(node);
         }
@@ -18327,6 +18337,8 @@ namespace ts {
                 case SyntaxKind.ParenthesizedType:
                 case SyntaxKind.TypeOperator:
                     return checkSourceElement((<ParenthesizedTypeNode | TypeOperatorNode>node).type);
+                case SyntaxKind.IndexedAccessType:
+                    return checkIndexedAccessType(<IndexedAccessTypeNode>node);
                 case SyntaxKind.FunctionDeclaration:
                     return checkFunctionDeclaration(<FunctionDeclaration>node);
                 case SyntaxKind.Block:
diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index 271e020c3896b..0bba375a2cb2e 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -415,8 +415,8 @@ namespace ts {
                     return emitParenType(<ParenthesizedTypeNode>type);
                 case SyntaxKind.TypeOperator:
                     return emitTypeOperator(<TypeOperatorNode>type);
-                case SyntaxKind.PropertyAccessType:
-                    return emitPropertyAccessType(<PropertyAccessTypeNode>type);
+                case SyntaxKind.IndexedAccessType:
+                    return emitPropertyAccessType(<IndexedAccessTypeNode>type);
                 case SyntaxKind.FunctionType:
                 case SyntaxKind.ConstructorType:
                     return emitSignatureDeclarationWithJsDocComments(<FunctionOrConstructorTypeNode>type);
@@ -516,10 +516,10 @@ namespace ts {
                 emitType(type.type);
             }
 
-            function emitPropertyAccessType(node: PropertyAccessTypeNode) {
+            function emitPropertyAccessType(node: IndexedAccessTypeNode) {
                 emitType(node.objectType);
                 write("[");
-                emitType(node.keyType);
+                emitType(node.indexType);
                 write("]");
             }
 
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index dde921765dfa2..f29ef0f4cf1e2 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -596,8 +596,8 @@ const _super = (function (geti, seti) {
                     return emitThisType();
                 case SyntaxKind.TypeOperator:
                     return emitTypeOperator(<TypeOperatorNode>node);
-                case SyntaxKind.PropertyAccessType:
-                    return emitPropertyAccessType(<PropertyAccessTypeNode>node);
+                case SyntaxKind.IndexedAccessType:
+                    return emitPropertyAccessType(<IndexedAccessTypeNode>node);
                 case SyntaxKind.LiteralType:
                     return emitLiteralType(<LiteralTypeNode>node);
 
@@ -1098,10 +1098,10 @@ const _super = (function (geti, seti) {
             emit(node.type);
         }
 
-        function emitPropertyAccessType(node: PropertyAccessTypeNode) {
+        function emitPropertyAccessType(node: IndexedAccessTypeNode) {
             emit(node.objectType);
             write("[");
-            emit(node.keyType);
+            emit(node.indexType);
             write("]");
         }
 
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 8fadb259184df..7b09327c1b882 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -136,9 +136,9 @@ namespace ts {
             case SyntaxKind.ParenthesizedType:
             case SyntaxKind.TypeOperator:
                 return visitNode(cbNode, (<ParenthesizedTypeNode | TypeOperatorNode>node).type);
-            case SyntaxKind.PropertyAccessType:
-                return visitNode(cbNode, (<PropertyAccessTypeNode>node).objectType) ||
-                    visitNode(cbNode, (<PropertyAccessTypeNode>node).keyType);
+            case SyntaxKind.IndexedAccessType:
+                return visitNode(cbNode, (<IndexedAccessTypeNode>node).objectType) ||
+                    visitNode(cbNode, (<IndexedAccessTypeNode>node).indexType);
             case SyntaxKind.LiteralType:
                 return visitNode(cbNode, (<LiteralTypeNode>node).literal);
             case SyntaxKind.ObjectBindingPattern:
@@ -2523,9 +2523,9 @@ namespace ts {
             let type = parseNonArrayType();
             while (!scanner.hasPrecedingLineBreak() && parseOptional(SyntaxKind.OpenBracketToken)) {
                 if (isStartOfType()) {
-                    const node = <PropertyAccessTypeNode>createNode(SyntaxKind.PropertyAccessType, type.pos);
+                    const node = <IndexedAccessTypeNode>createNode(SyntaxKind.IndexedAccessType, type.pos);
                     node.objectType = type;
-                    node.keyType = parseType();
+                    node.indexType = parseType();
                     parseExpected(SyntaxKind.CloseBracketToken);
                     type = finishNode(node);
                 }
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 6b0c92e3c8ea9..188364e0bd715 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -289,7 +289,7 @@ namespace ts {
                 case SyntaxKind.ParenthesizedType:
                 case SyntaxKind.ThisType:
                 case SyntaxKind.TypeOperator:
-                case SyntaxKind.PropertyAccessType:
+                case SyntaxKind.IndexedAccessType:
                 case SyntaxKind.LiteralType:
                     // TypeScript type nodes are elided.
 
@@ -1859,7 +1859,7 @@ namespace ts {
                     // Fallthrough
                 case SyntaxKind.TypeQuery:
                 case SyntaxKind.TypeOperator:
-                case SyntaxKind.PropertyAccessType:
+                case SyntaxKind.IndexedAccessType:
                 case SyntaxKind.TypeLiteral:
                 case SyntaxKind.AnyKeyword:
                 case SyntaxKind.ThisType:
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 3912c6e464278..54aabcc6a81eb 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -218,7 +218,7 @@ namespace ts {
         ParenthesizedType,
         ThisType,
         TypeOperator,
-        PropertyAccessType,
+        IndexedAccessType,
         LiteralType,
         // Binding patterns
         ObjectBindingPattern,
@@ -879,10 +879,10 @@ namespace ts {
         type: TypeNode;
     }
 
-    export interface PropertyAccessTypeNode extends TypeNode {
-        kind: SyntaxKind.PropertyAccessType;
+    export interface IndexedAccessTypeNode extends TypeNode {
+        kind: SyntaxKind.IndexedAccessType;
         objectType: TypeNode;
-        keyType: TypeNode;
+        indexType: TypeNode;
     }
 
     export interface LiteralTypeNode extends TypeNode {
@@ -2630,8 +2630,8 @@ namespace ts {
         Object                  = 1 << 15,  // Object type
         Union                   = 1 << 16,  // Union (T | U)
         Intersection            = 1 << 17,  // Intersection (T & U)
-        PropertyName            = 1 << 18,  // keyof T
-        PropertyAccess          = 1 << 19,  // T[K]
+        Index                   = 1 << 18,  // keyof T
+        IndexedAccess           = 1 << 19,  // T[K]
         /* @internal */
         FreshLiteral            = 1 << 20,  // Fresh literal type
         /* @internal */
@@ -2652,7 +2652,7 @@ namespace ts {
         Intrinsic = Any | String | Number | Boolean | BooleanLiteral | ESSymbol | Void | Undefined | Null | Never,
         /* @internal */
         Primitive = String | Number | Boolean | Enum | ESSymbol | Void | Undefined | Null | Literal,
-        StringLike = String | StringLiteral | PropertyName,
+        StringLike = String | StringLiteral | Index,
         NumberLike = Number | NumberLiteral | Enum | EnumLiteral,
         BooleanLike = Boolean | BooleanLiteral,
         EnumLike = Enum | EnumLiteral,
@@ -2662,7 +2662,7 @@ namespace ts {
 
         // 'Narrowable' types are types where narrowing actually narrows.
         // This *should* be every type other than null, undefined, void, and never
-        Narrowable = Any | StructuredType | TypeParameter | PropertyAccess | StringLike | NumberLike | BooleanLike | ESSymbol,
+        Narrowable = Any | StructuredType | TypeParameter | IndexedAccess | StringLike | NumberLike | BooleanLike | ESSymbol,
         NotUnionOrUnit = Any | ESSymbol | Object,
         /* @internal */
         RequiresWidening = ContainsWideningType | ContainsObjectLiteral,
@@ -2825,20 +2825,20 @@ namespace ts {
         /* @internal */
         resolvedApparentType: Type;
         /* @internal */
-        resolvedPropertyNameType: PropertyNameType;
+        resolvedIndexType: IndexType;
         /* @internal */
-        resolvedPropertyAccessTypes: PropertyAccessType[];
+        resolvedIndexedAccessTypes: IndexedAccessType[];
         /* @internal */
         isThisType?: boolean;
     }
 
-    export interface PropertyNameType extends Type {
+    export interface IndexType extends Type {
         type: TypeParameter;
     }
 
-    export interface PropertyAccessType extends Type {
+    export interface IndexedAccessType extends Type {
         objectType: Type;
-        keyType: TypeParameter;
+        indexType: TypeParameter;
     }
 
     export const enum SignatureKind {

From 3e18aba36adb7cca5b3376fb8eddf72a8f46d679 Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Wed, 26 Oct 2016 16:48:29 -0700
Subject: [PATCH 091/224] rewrite void-returning statements in constructors
 that capture result of super call (#11868)

* rewrite void-returning statements in constructors that capture result of super call

* linter
---
 src/compiler/transformers/es2015.ts           |  30 ++++-
 .../reference/constructorWithCapturedSuper.js | 123 ++++++++++++++++++
 .../constructorWithCapturedSuper.symbols      |  96 ++++++++++++++
 .../constructorWithCapturedSuper.types        | 113 ++++++++++++++++
 .../compiler/constructorWithCapturedSuper.ts  |  52 ++++++++
 5 files changed, 410 insertions(+), 4 deletions(-)
 create mode 100644 tests/baselines/reference/constructorWithCapturedSuper.js
 create mode 100644 tests/baselines/reference/constructorWithCapturedSuper.symbols
 create mode 100644 tests/baselines/reference/constructorWithCapturedSuper.types
 create mode 100644 tests/cases/compiler/constructorWithCapturedSuper.ts

diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
index b48539e872200..c0916d3233987 100644
--- a/src/compiler/transformers/es2015.ts
+++ b/src/compiler/transformers/es2015.ts
@@ -186,6 +186,7 @@ namespace ts {
         let enclosingFunction: FunctionLikeDeclaration;
         let enclosingNonArrowFunction: FunctionLikeDeclaration;
         let enclosingNonAsyncFunctionBody: FunctionLikeDeclaration | ClassElement;
+        let isInConstructorWithCapturedSuper: boolean;
 
         /**
          * Used to track if we are emitting body of the converted loop
@@ -231,14 +232,17 @@ namespace ts {
             const savedCurrentParent = currentParent;
             const savedCurrentNode = currentNode;
             const savedConvertedLoopState = convertedLoopState;
+            const savedIsInConstructorWithCapturedSuper = isInConstructorWithCapturedSuper;
             if (nodeStartsNewLexicalEnvironment(node)) {
-                // don't treat content of nodes that start new lexical environment as part of converted loop copy
+                // don't treat content of nodes that start new lexical environment as part of converted loop copy or constructor body
+                isInConstructorWithCapturedSuper = false;
                 convertedLoopState = undefined;
             }
 
             onBeforeVisitNode(node);
             const visited = f(node);
 
+            isInConstructorWithCapturedSuper = savedIsInConstructorWithCapturedSuper;
             convertedLoopState = savedConvertedLoopState;
             enclosingFunction = savedEnclosingFunction;
             enclosingNonArrowFunction = savedEnclosingNonArrowFunction;
@@ -251,6 +255,14 @@ namespace ts {
             return visited;
         }
 
+        function returnCapturedThis(node: Node): Node {
+            return setOriginalNode(createReturn(createIdentifier("_this")), node);
+        }
+
+        function isReturnVoidStatementInConstructorWithCapturedSuper(node: Node): boolean {
+            return isInConstructorWithCapturedSuper && node.kind === SyntaxKind.ReturnStatement && !(<ReturnStatement>node).expression;
+        }
+
         function shouldCheckNode(node: Node): boolean {
             return (node.transformFlags & TransformFlags.ES2015) !== 0 ||
                 node.kind === SyntaxKind.LabeledStatement ||
@@ -258,10 +270,16 @@ namespace ts {
         }
 
         function visitorWorker(node: Node): VisitResult<Node> {
-            if (shouldCheckNode(node)) {
+            if (isReturnVoidStatementInConstructorWithCapturedSuper(node)) {
+                return returnCapturedThis(<ReturnStatement>node);
+            }
+            else if (shouldCheckNode(node)) {
                 return visitJavaScript(node);
             }
-            else if (node.transformFlags & TransformFlags.ContainsES2015) {
+            else if (node.transformFlags & TransformFlags.ContainsES2015 || (isInConstructorWithCapturedSuper && !isExpression(node))) {
+                // we want to dive in this branch either if node has children with ES2015 specific syntax
+                // or we are inside constructor that captures result of the super call so all returns without expression should be
+                // rewritten. Note: we skip expressions since returns should never appear there 
                 return visitEachChild(node, visitor, context);
             }
             else {
@@ -283,6 +301,7 @@ namespace ts {
         function visitNodesInConvertedLoop(node: Node): VisitResult<Node> {
             switch (node.kind) {
                 case SyntaxKind.ReturnStatement:
+                    node = isReturnVoidStatementInConstructorWithCapturedSuper(node) ? returnCapturedThis(node) : node;
                     return visitReturnStatement(<ReturnStatement>node);
 
                 case SyntaxKind.VariableStatement:
@@ -864,7 +883,10 @@ namespace ts {
             }
 
             if (constructor) {
-                const body = saveStateAndInvoke(constructor, constructor => visitNodes(constructor.body.statements, visitor, isStatement, /*start*/ statementOffset));
+                const body = saveStateAndInvoke(constructor, constructor => {
+                    isInConstructorWithCapturedSuper = superCaptureStatus === SuperCaptureResult.ReplaceSuperCapture;
+                    return visitNodes(constructor.body.statements, visitor, isStatement, /*start*/ statementOffset);
+                });
                 addRange(statements, body);
             }
 
diff --git a/tests/baselines/reference/constructorWithCapturedSuper.js b/tests/baselines/reference/constructorWithCapturedSuper.js
new file mode 100644
index 0000000000000..895f78eb04b8b
--- /dev/null
+++ b/tests/baselines/reference/constructorWithCapturedSuper.js
@@ -0,0 +1,123 @@
+//// [constructorWithCapturedSuper.ts]
+let oneA: A;
+
+class A {
+    constructor() {
+        return oneA;
+    }
+}
+
+class B extends A {
+    constructor(x: number) {
+        super();
+        if (x === 1) {
+            return;
+        }
+        while (x < 2) {
+            return;
+        }
+        try {
+            return
+        }
+        catch (e) {
+            return;
+        }
+        finally {
+            return;
+        }
+    }
+}
+
+class C extends A {
+    constructor(x: number) {
+        super();
+        for (let i = 0; i < 10; ++i) {
+            () => i + x;
+            if (x === 1) {
+                return;
+            } 
+        }
+    }
+}
+
+class D extends A {
+    constructor(x: number) {
+        super();
+        () => {
+            return;
+        }
+        function foo() {
+            return;
+        }
+    }
+}
+
+//// [constructorWithCapturedSuper.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var oneA;
+var A = (function () {
+    function A() {
+        return oneA;
+    }
+    return A;
+}());
+var B = (function (_super) {
+    __extends(B, _super);
+    function B(x) {
+        var _this = _super.call(this) || this;
+        if (x === 1) {
+            return _this;
+        }
+        while (x < 2) {
+            return _this;
+        }
+        try {
+            return _this;
+        }
+        catch (e) {
+            return _this;
+        }
+        finally {
+            return _this;
+        }
+        return _this;
+    }
+    return B;
+}(A));
+var C = (function (_super) {
+    __extends(C, _super);
+    function C(x) {
+        var _this = _super.call(this) || this;
+        var _loop_1 = function (i) {
+            (function () { return i + x; });
+            if (x === 1) {
+                return { value: _this };
+            }
+        };
+        for (var i = 0; i < 10; ++i) {
+            var state_1 = _loop_1(i);
+            if (typeof state_1 === "object")
+                return state_1.value;
+        }
+        return _this;
+    }
+    return C;
+}(A));
+var D = (function (_super) {
+    __extends(D, _super);
+    function D(x) {
+        var _this = _super.call(this) || this;
+        (function () {
+            return;
+        });
+        function foo() {
+            return;
+        }
+        return _this;
+    }
+    return D;
+}(A));
diff --git a/tests/baselines/reference/constructorWithCapturedSuper.symbols b/tests/baselines/reference/constructorWithCapturedSuper.symbols
new file mode 100644
index 0000000000000..1743ee61612e0
--- /dev/null
+++ b/tests/baselines/reference/constructorWithCapturedSuper.symbols
@@ -0,0 +1,96 @@
+=== tests/cases/compiler/constructorWithCapturedSuper.ts ===
+let oneA: A;
+>oneA : Symbol(oneA, Decl(constructorWithCapturedSuper.ts, 0, 3))
+>A : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+class A {
+>A : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+    constructor() {
+        return oneA;
+>oneA : Symbol(oneA, Decl(constructorWithCapturedSuper.ts, 0, 3))
+    }
+}
+
+class B extends A {
+>B : Symbol(B, Decl(constructorWithCapturedSuper.ts, 6, 1))
+>A : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+    constructor(x: number) {
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 9, 16))
+
+        super();
+>super : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+        if (x === 1) {
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 9, 16))
+
+            return;
+        }
+        while (x < 2) {
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 9, 16))
+
+            return;
+        }
+        try {
+            return
+        }
+        catch (e) {
+>e : Symbol(e, Decl(constructorWithCapturedSuper.ts, 20, 15))
+
+            return;
+        }
+        finally {
+            return;
+        }
+    }
+}
+
+class C extends A {
+>C : Symbol(C, Decl(constructorWithCapturedSuper.ts, 27, 1))
+>A : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+    constructor(x: number) {
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 30, 16))
+
+        super();
+>super : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+        for (let i = 0; i < 10; ++i) {
+>i : Symbol(i, Decl(constructorWithCapturedSuper.ts, 32, 16))
+>i : Symbol(i, Decl(constructorWithCapturedSuper.ts, 32, 16))
+>i : Symbol(i, Decl(constructorWithCapturedSuper.ts, 32, 16))
+
+            () => i + x;
+>i : Symbol(i, Decl(constructorWithCapturedSuper.ts, 32, 16))
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 30, 16))
+
+            if (x === 1) {
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 30, 16))
+
+                return;
+            } 
+        }
+    }
+}
+
+class D extends A {
+>D : Symbol(D, Decl(constructorWithCapturedSuper.ts, 39, 1))
+>A : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+    constructor(x: number) {
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 42, 16))
+
+        super();
+>super : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+        () => {
+            return;
+        }
+        function foo() {
+>foo : Symbol(foo, Decl(constructorWithCapturedSuper.ts, 46, 9))
+
+            return;
+        }
+    }
+}
diff --git a/tests/baselines/reference/constructorWithCapturedSuper.types b/tests/baselines/reference/constructorWithCapturedSuper.types
new file mode 100644
index 0000000000000..13696029d536f
--- /dev/null
+++ b/tests/baselines/reference/constructorWithCapturedSuper.types
@@ -0,0 +1,113 @@
+=== tests/cases/compiler/constructorWithCapturedSuper.ts ===
+let oneA: A;
+>oneA : A
+>A : A
+
+class A {
+>A : A
+
+    constructor() {
+        return oneA;
+>oneA : A
+    }
+}
+
+class B extends A {
+>B : B
+>A : A
+
+    constructor(x: number) {
+>x : number
+
+        super();
+>super() : void
+>super : typeof A
+
+        if (x === 1) {
+>x === 1 : boolean
+>x : number
+>1 : 1
+
+            return;
+        }
+        while (x < 2) {
+>x < 2 : boolean
+>x : number
+>2 : 2
+
+            return;
+        }
+        try {
+            return
+        }
+        catch (e) {
+>e : any
+
+            return;
+        }
+        finally {
+            return;
+        }
+    }
+}
+
+class C extends A {
+>C : C
+>A : A
+
+    constructor(x: number) {
+>x : number
+
+        super();
+>super() : void
+>super : typeof A
+
+        for (let i = 0; i < 10; ++i) {
+>i : number
+>0 : 0
+>i < 10 : boolean
+>i : number
+>10 : 10
+>++i : number
+>i : number
+
+            () => i + x;
+>() => i + x : () => number
+>i + x : number
+>i : number
+>x : number
+
+            if (x === 1) {
+>x === 1 : boolean
+>x : number
+>1 : 1
+
+                return;
+            } 
+        }
+    }
+}
+
+class D extends A {
+>D : D
+>A : A
+
+    constructor(x: number) {
+>x : number
+
+        super();
+>super() : void
+>super : typeof A
+
+        () => {
+>() => {            return;        } : () => void
+
+            return;
+        }
+        function foo() {
+>foo : () => void
+
+            return;
+        }
+    }
+}
diff --git a/tests/cases/compiler/constructorWithCapturedSuper.ts b/tests/cases/compiler/constructorWithCapturedSuper.ts
new file mode 100644
index 0000000000000..942803e771de6
--- /dev/null
+++ b/tests/cases/compiler/constructorWithCapturedSuper.ts
@@ -0,0 +1,52 @@
+let oneA: A;
+
+class A {
+    constructor() {
+        return oneA;
+    }
+}
+
+class B extends A {
+    constructor(x: number) {
+        super();
+        if (x === 1) {
+            return;
+        }
+        while (x < 2) {
+            return;
+        }
+        try {
+            return
+        }
+        catch (e) {
+            return;
+        }
+        finally {
+            return;
+        }
+    }
+}
+
+class C extends A {
+    constructor(x: number) {
+        super();
+        for (let i = 0; i < 10; ++i) {
+            () => i + x;
+            if (x === 1) {
+                return;
+            } 
+        }
+    }
+}
+
+class D extends A {
+    constructor(x: number) {
+        super();
+        () => {
+            return;
+        }
+        function foo() {
+            return;
+        }
+    }
+}
\ No newline at end of file

From 50e2fd87daf9b0f7fceaae27661b42c5b3240256 Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Wed, 26 Oct 2016 17:15:04 -0700
Subject: [PATCH 092/224] only emit /// types reference for a symbol in d.ts
 file if all declarations of a symbol come from type reference directives
 (#11872)

* only emit /// types reference for a symbol in d.ts file if all declarations of a symbol come from type reference directives

* pass proper value for current directory when compiling .d.ts files
---
 src/compiler/checker.ts                       |  4 ++++
 src/harness/harness.ts                        |  2 +-
 .../declarationFilesWithTypeReferences1.js    | 22 +++++++++++++++++
 ...eclarationFilesWithTypeReferences1.symbols | 18 ++++++++++++++
 .../declarationFilesWithTypeReferences1.types | 18 ++++++++++++++
 .../declarationFilesWithTypeReferences2.js    | 23 ++++++++++++++++++
 ...eclarationFilesWithTypeReferences2.symbols | 18 ++++++++++++++
 .../declarationFilesWithTypeReferences2.types | 18 ++++++++++++++
 .../declarationFilesWithTypeReferences3.js    | 24 +++++++++++++++++++
 ...eclarationFilesWithTypeReferences3.symbols | 18 ++++++++++++++
 .../declarationFilesWithTypeReferences3.types | 18 ++++++++++++++
 .../declarationFilesWithTypeReferences4.js    | 23 ++++++++++++++++++
 ...eclarationFilesWithTypeReferences4.symbols | 18 ++++++++++++++
 .../declarationFilesWithTypeReferences4.types | 18 ++++++++++++++
 .../declarationFilesWithTypeReferences1.ts    | 14 +++++++++++
 .../declarationFilesWithTypeReferences2.ts    | 14 +++++++++++
 .../declarationFilesWithTypeReferences3.ts    | 12 ++++++++++
 .../declarationFilesWithTypeReferences4.ts    | 12 ++++++++++
 18 files changed, 293 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/declarationFilesWithTypeReferences1.js
 create mode 100644 tests/baselines/reference/declarationFilesWithTypeReferences1.symbols
 create mode 100644 tests/baselines/reference/declarationFilesWithTypeReferences1.types
 create mode 100644 tests/baselines/reference/declarationFilesWithTypeReferences2.js
 create mode 100644 tests/baselines/reference/declarationFilesWithTypeReferences2.symbols
 create mode 100644 tests/baselines/reference/declarationFilesWithTypeReferences2.types
 create mode 100644 tests/baselines/reference/declarationFilesWithTypeReferences3.js
 create mode 100644 tests/baselines/reference/declarationFilesWithTypeReferences3.symbols
 create mode 100644 tests/baselines/reference/declarationFilesWithTypeReferences3.types
 create mode 100644 tests/baselines/reference/declarationFilesWithTypeReferences4.js
 create mode 100644 tests/baselines/reference/declarationFilesWithTypeReferences4.symbols
 create mode 100644 tests/baselines/reference/declarationFilesWithTypeReferences4.types
 create mode 100644 tests/cases/compiler/declarationFilesWithTypeReferences1.ts
 create mode 100644 tests/cases/compiler/declarationFilesWithTypeReferences2.ts
 create mode 100644 tests/cases/compiler/declarationFilesWithTypeReferences3.ts
 create mode 100644 tests/cases/compiler/declarationFilesWithTypeReferences4.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 3c98513423af2..4fa146584943b 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -19505,6 +19505,10 @@ namespace ts {
                         if (typeReferenceDirective) {
                             (typeReferenceDirectives || (typeReferenceDirectives = [])).push(typeReferenceDirective);
                         }
+                        else {
+                            // found at least one entry that does not originate from type reference directive 
+                            return undefined;
+                        }
                     }
                 }
                 return typeReferenceDirectives;
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index 409ab9e2fcc9a..47b76793af6af 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -1238,7 +1238,7 @@ namespace Harness {
             if (options.declaration && result.errors.length === 0 && result.declFilesCode.length > 0) {
                 ts.forEach(inputFiles, file => addDtsFile(file, declInputFiles));
                 ts.forEach(otherFiles, file => addDtsFile(file, declOtherFiles));
-                const output = compileFiles(declInputFiles, declOtherFiles, harnessSettings, options, currentDirectory);
+                const output = compileFiles(declInputFiles, declOtherFiles, harnessSettings, options, currentDirectory || harnessSettings["currentDirectory"]);
                 return { declInputFiles, declOtherFiles, declResult: output.result };
             }
 
diff --git a/tests/baselines/reference/declarationFilesWithTypeReferences1.js b/tests/baselines/reference/declarationFilesWithTypeReferences1.js
new file mode 100644
index 0000000000000..b4695f28f134f
--- /dev/null
+++ b/tests/baselines/reference/declarationFilesWithTypeReferences1.js
@@ -0,0 +1,22 @@
+//// [tests/cases/compiler/declarationFilesWithTypeReferences1.ts] ////
+
+//// [index.d.ts]
+
+interface Error {
+    stack2: string;
+}
+
+//// [app.ts]
+
+function foo(): Error {
+    return undefined;
+}
+
+//// [app.js]
+function foo() {
+    return undefined;
+}
+
+
+//// [app.d.ts]
+declare function foo(): Error;
diff --git a/tests/baselines/reference/declarationFilesWithTypeReferences1.symbols b/tests/baselines/reference/declarationFilesWithTypeReferences1.symbols
new file mode 100644
index 0000000000000..3d3df3c162280
--- /dev/null
+++ b/tests/baselines/reference/declarationFilesWithTypeReferences1.symbols
@@ -0,0 +1,18 @@
+=== /node_modules/@types/node/index.d.ts ===
+
+interface Error {
+>Error : Symbol(Error, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(index.d.ts, 0, 0))
+
+    stack2: string;
+>stack2 : Symbol(Error.stack2, Decl(index.d.ts, 1, 17))
+}
+
+=== /app.ts ===
+
+function foo(): Error {
+>foo : Symbol(foo, Decl(app.ts, 0, 0))
+>Error : Symbol(Error, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(index.d.ts, 0, 0))
+
+    return undefined;
+>undefined : Symbol(undefined)
+}
diff --git a/tests/baselines/reference/declarationFilesWithTypeReferences1.types b/tests/baselines/reference/declarationFilesWithTypeReferences1.types
new file mode 100644
index 0000000000000..7837b7b3a6c0e
--- /dev/null
+++ b/tests/baselines/reference/declarationFilesWithTypeReferences1.types
@@ -0,0 +1,18 @@
+=== /node_modules/@types/node/index.d.ts ===
+
+interface Error {
+>Error : Error
+
+    stack2: string;
+>stack2 : string
+}
+
+=== /app.ts ===
+
+function foo(): Error {
+>foo : () => Error
+>Error : Error
+
+    return undefined;
+>undefined : undefined
+}
diff --git a/tests/baselines/reference/declarationFilesWithTypeReferences2.js b/tests/baselines/reference/declarationFilesWithTypeReferences2.js
new file mode 100644
index 0000000000000..b85dcc4510757
--- /dev/null
+++ b/tests/baselines/reference/declarationFilesWithTypeReferences2.js
@@ -0,0 +1,23 @@
+//// [tests/cases/compiler/declarationFilesWithTypeReferences2.ts] ////
+
+//// [index.d.ts]
+
+interface Error2 {
+    stack2: string;
+}
+
+//// [app.ts]
+
+function foo(): Error2 {
+    return undefined;
+}
+
+//// [app.js]
+function foo() {
+    return undefined;
+}
+
+
+//// [app.d.ts]
+/// <reference types="node" />
+declare function foo(): Error2;
diff --git a/tests/baselines/reference/declarationFilesWithTypeReferences2.symbols b/tests/baselines/reference/declarationFilesWithTypeReferences2.symbols
new file mode 100644
index 0000000000000..dc6d8a3a6de2b
--- /dev/null
+++ b/tests/baselines/reference/declarationFilesWithTypeReferences2.symbols
@@ -0,0 +1,18 @@
+=== /node_modules/@types/node/index.d.ts ===
+
+interface Error2 {
+>Error2 : Symbol(Error2, Decl(index.d.ts, 0, 0))
+
+    stack2: string;
+>stack2 : Symbol(Error2.stack2, Decl(index.d.ts, 1, 18))
+}
+
+=== /app.ts ===
+
+function foo(): Error2 {
+>foo : Symbol(foo, Decl(app.ts, 0, 0))
+>Error2 : Symbol(Error2, Decl(index.d.ts, 0, 0))
+
+    return undefined;
+>undefined : Symbol(undefined)
+}
diff --git a/tests/baselines/reference/declarationFilesWithTypeReferences2.types b/tests/baselines/reference/declarationFilesWithTypeReferences2.types
new file mode 100644
index 0000000000000..c56f4ba6a67d2
--- /dev/null
+++ b/tests/baselines/reference/declarationFilesWithTypeReferences2.types
@@ -0,0 +1,18 @@
+=== /node_modules/@types/node/index.d.ts ===
+
+interface Error2 {
+>Error2 : Error2
+
+    stack2: string;
+>stack2 : string
+}
+
+=== /app.ts ===
+
+function foo(): Error2 {
+>foo : () => Error2
+>Error2 : Error2
+
+    return undefined;
+>undefined : undefined
+}
diff --git a/tests/baselines/reference/declarationFilesWithTypeReferences3.js b/tests/baselines/reference/declarationFilesWithTypeReferences3.js
new file mode 100644
index 0000000000000..3a18859c61090
--- /dev/null
+++ b/tests/baselines/reference/declarationFilesWithTypeReferences3.js
@@ -0,0 +1,24 @@
+//// [tests/cases/compiler/declarationFilesWithTypeReferences3.ts] ////
+
+//// [index.d.ts]
+
+interface Error2 {
+    stack2: string;
+}
+
+//// [app.ts]
+/// <reference types="node"/>
+function foo(): Error2 {
+    return undefined;
+}
+
+//// [app.js]
+/// <reference types="node"/>
+function foo() {
+    return undefined;
+}
+
+
+//// [app.d.ts]
+/// <reference types="node" />
+declare function foo(): Error2;
diff --git a/tests/baselines/reference/declarationFilesWithTypeReferences3.symbols b/tests/baselines/reference/declarationFilesWithTypeReferences3.symbols
new file mode 100644
index 0000000000000..78335f988e9b7
--- /dev/null
+++ b/tests/baselines/reference/declarationFilesWithTypeReferences3.symbols
@@ -0,0 +1,18 @@
+=== /a/node_modules/@types/node/index.d.ts ===
+
+interface Error2 {
+>Error2 : Symbol(Error2, Decl(index.d.ts, 0, 0))
+
+    stack2: string;
+>stack2 : Symbol(Error2.stack2, Decl(index.d.ts, 1, 18))
+}
+
+=== /a/app.ts ===
+/// <reference types="node"/>
+function foo(): Error2 {
+>foo : Symbol(foo, Decl(app.ts, 0, 0))
+>Error2 : Symbol(Error2, Decl(index.d.ts, 0, 0))
+
+    return undefined;
+>undefined : Symbol(undefined)
+}
diff --git a/tests/baselines/reference/declarationFilesWithTypeReferences3.types b/tests/baselines/reference/declarationFilesWithTypeReferences3.types
new file mode 100644
index 0000000000000..9ac0105890abc
--- /dev/null
+++ b/tests/baselines/reference/declarationFilesWithTypeReferences3.types
@@ -0,0 +1,18 @@
+=== /a/node_modules/@types/node/index.d.ts ===
+
+interface Error2 {
+>Error2 : Error2
+
+    stack2: string;
+>stack2 : string
+}
+
+=== /a/app.ts ===
+/// <reference types="node"/>
+function foo(): Error2 {
+>foo : () => Error2
+>Error2 : Error2
+
+    return undefined;
+>undefined : undefined
+}
diff --git a/tests/baselines/reference/declarationFilesWithTypeReferences4.js b/tests/baselines/reference/declarationFilesWithTypeReferences4.js
new file mode 100644
index 0000000000000..b45860be9bb82
--- /dev/null
+++ b/tests/baselines/reference/declarationFilesWithTypeReferences4.js
@@ -0,0 +1,23 @@
+//// [tests/cases/compiler/declarationFilesWithTypeReferences4.ts] ////
+
+//// [index.d.ts]
+
+interface Error {
+    stack2: string;
+}
+
+//// [app.ts]
+/// <reference types="node"/>
+function foo(): Error {
+    return undefined;
+}
+
+//// [app.js]
+/// <reference types="node"/>
+function foo() {
+    return undefined;
+}
+
+
+//// [app.d.ts]
+declare function foo(): Error;
diff --git a/tests/baselines/reference/declarationFilesWithTypeReferences4.symbols b/tests/baselines/reference/declarationFilesWithTypeReferences4.symbols
new file mode 100644
index 0000000000000..216bd2a6a1c7d
--- /dev/null
+++ b/tests/baselines/reference/declarationFilesWithTypeReferences4.symbols
@@ -0,0 +1,18 @@
+=== /a/node_modules/@types/node/index.d.ts ===
+
+interface Error {
+>Error : Symbol(Error, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(index.d.ts, 0, 0))
+
+    stack2: string;
+>stack2 : Symbol(Error.stack2, Decl(index.d.ts, 1, 17))
+}
+
+=== /a/app.ts ===
+/// <reference types="node"/>
+function foo(): Error {
+>foo : Symbol(foo, Decl(app.ts, 0, 0))
+>Error : Symbol(Error, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(index.d.ts, 0, 0))
+
+    return undefined;
+>undefined : Symbol(undefined)
+}
diff --git a/tests/baselines/reference/declarationFilesWithTypeReferences4.types b/tests/baselines/reference/declarationFilesWithTypeReferences4.types
new file mode 100644
index 0000000000000..0ae603716b100
--- /dev/null
+++ b/tests/baselines/reference/declarationFilesWithTypeReferences4.types
@@ -0,0 +1,18 @@
+=== /a/node_modules/@types/node/index.d.ts ===
+
+interface Error {
+>Error : Error
+
+    stack2: string;
+>stack2 : string
+}
+
+=== /a/app.ts ===
+/// <reference types="node"/>
+function foo(): Error {
+>foo : () => Error
+>Error : Error
+
+    return undefined;
+>undefined : undefined
+}
diff --git a/tests/cases/compiler/declarationFilesWithTypeReferences1.ts b/tests/cases/compiler/declarationFilesWithTypeReferences1.ts
new file mode 100644
index 0000000000000..e499543057e97
--- /dev/null
+++ b/tests/cases/compiler/declarationFilesWithTypeReferences1.ts
@@ -0,0 +1,14 @@
+// @types: node
+// @declaration: true
+// @currentDirectory: /
+
+// @filename: /node_modules/@types/node/index.d.ts
+interface Error {
+    stack2: string;
+}
+
+// @filename: /app.ts
+
+function foo(): Error {
+    return undefined;
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/declarationFilesWithTypeReferences2.ts b/tests/cases/compiler/declarationFilesWithTypeReferences2.ts
new file mode 100644
index 0000000000000..0514895563774
--- /dev/null
+++ b/tests/cases/compiler/declarationFilesWithTypeReferences2.ts
@@ -0,0 +1,14 @@
+// @types: node
+// @declaration: true
+// @currentDirectory: /
+
+// @filename: /node_modules/@types/node/index.d.ts
+interface Error2 {
+    stack2: string;
+}
+
+// @filename: /app.ts
+
+function foo(): Error2 {
+    return undefined;
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/declarationFilesWithTypeReferences3.ts b/tests/cases/compiler/declarationFilesWithTypeReferences3.ts
new file mode 100644
index 0000000000000..6653fb11f8b44
--- /dev/null
+++ b/tests/cases/compiler/declarationFilesWithTypeReferences3.ts
@@ -0,0 +1,12 @@
+// @declaration: true
+
+// @filename: /a/node_modules/@types/node/index.d.ts
+interface Error2 {
+    stack2: string;
+}
+
+// @filename: /a/app.ts
+/// <reference types="node"/>
+function foo(): Error2 {
+    return undefined;
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/declarationFilesWithTypeReferences4.ts b/tests/cases/compiler/declarationFilesWithTypeReferences4.ts
new file mode 100644
index 0000000000000..4719feb56642e
--- /dev/null
+++ b/tests/cases/compiler/declarationFilesWithTypeReferences4.ts
@@ -0,0 +1,12 @@
+// @declaration: true
+
+// @filename: /a/node_modules/@types/node/index.d.ts
+interface Error {
+    stack2: string;
+}
+
+// @filename: /a/app.ts
+/// <reference types="node"/>
+function foo(): Error {
+    return undefined;
+}
\ No newline at end of file

From 8448e741c924ebe56a029f53cd5bd3e9f5b6a226 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 27 Oct 2016 08:08:02 -0700
Subject: [PATCH 093/224] Fix bug: Return a resolution diagnostic for a `.jsx`
 import if `--allowJs` is turned off

---
 src/compiler/program.ts                         | 14 ++++++++++----
 ...utionWithExtensions_notSupported3.errors.txt | 12 ++++++++++++
 ...uleResolutionWithExtensions_notSupported3.js | 12 ++++++++++++
 ...utionWithExtensions_notSupported3.trace.json | 17 +++++++++++++++++
 ...uleResolutionWithExtensions_notSupported3.ts |  9 +++++++++
 5 files changed, 60 insertions(+), 4 deletions(-)
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.errors.txt
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.js
 create mode 100644 tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.trace.json
 create mode 100644 tests/cases/compiler/moduleResolutionWithExtensions_notSupported3.ts

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index fab35141ba4af..431479752d1c3 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1580,13 +1580,19 @@ namespace ts {
             case Extension.Dts:
                 // These are always allowed.
                 return undefined;
-
             case Extension.Tsx:
+                return needJsx();
             case Extension.Jsx:
-                return options.jsx ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set;
-
+                return needJsx() || needAllowJs();
             case Extension.Js:
-                return options.allowJs ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_allowJs_is_not_set;
+                return needAllowJs();
+        }
+
+        function needJsx() {
+            return options.jsx ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set;
+        }
+        function needAllowJs() {
+            return options.allowJs ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_allowJs_is_not_set;
         }
     }
 }
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.errors.txt b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.errors.txt
new file mode 100644
index 0000000000000..45e058bae54ed
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.errors.txt
@@ -0,0 +1,12 @@
+/a.ts(1,17): error TS6143: Module './jsx' was resolved to '/jsx.jsx', but '--allowJs' is not set.
+
+
+==== /a.ts (1 errors) ====
+    import jsx from "./jsx";
+                    ~~~~~~~
+!!! error TS6143: Module './jsx' was resolved to '/jsx.jsx', but '--allowJs' is not set.
+    
+==== /jsx.jsx (0 errors) ====
+    // Test the error message if we have `--jsx` but not `--allowJw`.
+    
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.js b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.js
new file mode 100644
index 0000000000000..f362701bbda71
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.js
@@ -0,0 +1,12 @@
+//// [tests/cases/compiler/moduleResolutionWithExtensions_notSupported3.ts] ////
+
+//// [jsx.jsx]
+// Test the error message if we have `--jsx` but not `--allowJw`.
+
+
+//// [a.ts]
+import jsx from "./jsx";
+
+
+//// [a.js]
+"use strict";
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.trace.json
new file mode 100644
index 0000000000000..c366843ce86e6
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.trace.json
@@ -0,0 +1,17 @@
+[
+    "======== Resolving module './jsx' from '/a.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module as file / folder, candidate module location '/jsx'.",
+    "File '/jsx.ts' does not exist.",
+    "File '/jsx.tsx' does not exist.",
+    "File '/jsx.d.ts' does not exist.",
+    "File '/jsx/package.json' does not exist.",
+    "File '/jsx/index.ts' does not exist.",
+    "File '/jsx/index.tsx' does not exist.",
+    "File '/jsx/index.d.ts' does not exist.",
+    "Loading module as file / folder, candidate module location '/jsx'.",
+    "File '/jsx.js' does not exist.",
+    "File '/jsx.jsx' exist - use it as a name resolution result.",
+    "Resolving real path for '/jsx.jsx', result '/jsx.jsx'",
+    "======== Module name './jsx' was successfully resolved to '/jsx.jsx'. ========"
+]
\ No newline at end of file
diff --git a/tests/cases/compiler/moduleResolutionWithExtensions_notSupported3.ts b/tests/cases/compiler/moduleResolutionWithExtensions_notSupported3.ts
new file mode 100644
index 0000000000000..e06f603377c19
--- /dev/null
+++ b/tests/cases/compiler/moduleResolutionWithExtensions_notSupported3.ts
@@ -0,0 +1,9 @@
+// @noImplicitReferences: true
+// @jsx: preserve
+// @traceResolution: true
+// Test the error message if we have `--jsx` but not `--allowJw`.
+
+// @Filename: /jsx.jsx
+
+// @Filename: /a.ts
+import jsx from "./jsx";

From 91885266acea1fb835eec00c066c20ef12e0ca49 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 27 Oct 2016 08:09:59 -0700
Subject: [PATCH 094/224] Remove a comment about a parameter that no longer
 exists

---
 src/compiler/program.ts | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index fab35141ba4af..6f6c5e3ee3b86 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1078,9 +1078,6 @@ namespace ts {
             }
         }
 
-        /**
-          * 'isReference' indicates whether the file was brought in via a reference directive (rather than an import declaration)
-          */
         function processSourceFile(fileName: string, isDefaultLib: boolean, refFile?: SourceFile, refPos?: number, refEnd?: number) {
             let diagnosticArgument: string[];
             let diagnostic: DiagnosticMessage;

From ed82fddb8cc540966f109d486de950a29132814d Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 27 Oct 2016 08:14:08 -0700
Subject: [PATCH 095/224] Fix bug: We want to test for existence of the enum
 value, not whether it's non-zero

---
 src/compiler/program.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index fab35141ba4af..6273d2b3117cd 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -333,7 +333,7 @@ namespace ts {
         if (host.resolveModuleNames) {
             resolveModuleNamesWorker = (moduleNames, containingFile) => host.resolveModuleNames(moduleNames, containingFile).map(resolved => {
                 // An older host may have omitted extension, in which case we should infer it from the file extension of resolvedFileName.
-                if (!resolved || resolved.extension) {
+                if (!resolved || resolved.extension === undefined) {
                     return resolved;
                 }
                 resolved = clone(resolved);

From 4e20882ac01df80fff4b9ab97fca968bc0bcc3bf Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 27 Oct 2016 08:43:22 -0700
Subject: [PATCH 096/224] Fix: test for presence, not absence

---
 src/compiler/program.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 6273d2b3117cd..8c0da2562e91e 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -333,7 +333,7 @@ namespace ts {
         if (host.resolveModuleNames) {
             resolveModuleNamesWorker = (moduleNames, containingFile) => host.resolveModuleNames(moduleNames, containingFile).map(resolved => {
                 // An older host may have omitted extension, in which case we should infer it from the file extension of resolvedFileName.
-                if (!resolved || resolved.extension === undefined) {
+                if (!resolved || resolved.extension !== undefined) {
                     return resolved;
                 }
                 resolved = clone(resolved);

From 4937d9c8b45e950cdd1095be0afeb07fe032aa6f Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 27 Oct 2016 07:19:37 -0700
Subject: [PATCH 097/224] Allow untyped imports

---
 src/compiler/checker.ts                       | 35 ++++++++++++++---
 src/compiler/diagnosticMessages.json          |  4 ++
 src/compiler/program.ts                       |  4 +-
 src/compiler/utilities.ts                     |  5 ++-
 src/harness/harness.ts                        | 38 +++++++++++--------
 .../reference/untypedModuleImport.js          | 37 ++++++++++++++++++
 .../reference/untypedModuleImport.symbols     | 25 ++++++++++++
 .../reference/untypedModuleImport.types       | 31 +++++++++++++++
 .../reference/untypedModuleImport_allowJs.js  | 16 ++++++++
 .../untypedModuleImport_allowJs.symbols       | 17 +++++++++
 .../untypedModuleImport_allowJs.types         | 22 +++++++++++
 ...typedModuleImport_noImplicitAny.errors.txt | 13 +++++++
 .../untypedModuleImport_noImplicitAny.js      | 13 +++++++
 ...ypedModuleImport_noLocalImports.errors.txt | 13 +++++++
 .../untypedModuleImport_noLocalImports.js     | 13 +++++++
 .../untypedModuleImport_vsAmbient.js          | 23 +++++++++++
 .../untypedModuleImport_vsAmbient.symbols     | 14 +++++++
 .../untypedModuleImport_vsAmbient.types       | 14 +++++++
 .../moduleResolution/untypedModuleImport.ts   | 21 ++++++++++
 .../untypedModuleImport_allowJs.ts            | 12 ++++++
 .../untypedModuleImport_noImplicitAny.ts      | 10 +++++
 .../untypedModuleImport_noLocalImports.ts     |  9 +++++
 .../untypedModuleImport_vsAmbient.ts          | 16 ++++++++
 tests/cases/fourslash/untypedModuleImport.ts  | 22 +++++++++++
 24 files changed, 402 insertions(+), 25 deletions(-)
 create mode 100644 tests/baselines/reference/untypedModuleImport.js
 create mode 100644 tests/baselines/reference/untypedModuleImport.symbols
 create mode 100644 tests/baselines/reference/untypedModuleImport.types
 create mode 100644 tests/baselines/reference/untypedModuleImport_allowJs.js
 create mode 100644 tests/baselines/reference/untypedModuleImport_allowJs.symbols
 create mode 100644 tests/baselines/reference/untypedModuleImport_allowJs.types
 create mode 100644 tests/baselines/reference/untypedModuleImport_noImplicitAny.errors.txt
 create mode 100644 tests/baselines/reference/untypedModuleImport_noImplicitAny.js
 create mode 100644 tests/baselines/reference/untypedModuleImport_noLocalImports.errors.txt
 create mode 100644 tests/baselines/reference/untypedModuleImport_noLocalImports.js
 create mode 100644 tests/baselines/reference/untypedModuleImport_vsAmbient.js
 create mode 100644 tests/baselines/reference/untypedModuleImport_vsAmbient.symbols
 create mode 100644 tests/baselines/reference/untypedModuleImport_vsAmbient.types
 create mode 100644 tests/cases/conformance/moduleResolution/untypedModuleImport.ts
 create mode 100644 tests/cases/conformance/moduleResolution/untypedModuleImport_allowJs.ts
 create mode 100644 tests/cases/conformance/moduleResolution/untypedModuleImport_noImplicitAny.ts
 create mode 100644 tests/cases/conformance/moduleResolution/untypedModuleImport_noLocalImports.ts
 create mode 100644 tests/cases/conformance/moduleResolution/untypedModuleImport_vsAmbient.ts
 create mode 100644 tests/cases/fourslash/untypedModuleImport.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 4aee170f195d4..f9c00b5c1587f 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -1069,7 +1069,7 @@ namespace ts {
             const moduleSymbol = resolveExternalModuleName(node, (<ImportDeclaration>node.parent).moduleSpecifier);
 
             if (moduleSymbol) {
-                const exportDefaultSymbol = isShorthandAmbientModuleSymbol(moduleSymbol) ?
+                const exportDefaultSymbol = isUntypedModuleSymbol(moduleSymbol) ?
                     moduleSymbol :
                     moduleSymbol.exports["export="] ?
                         getPropertyOfType(getTypeOfSymbol(moduleSymbol.exports["export="]), "default") :
@@ -1145,7 +1145,7 @@ namespace ts {
             if (targetSymbol) {
                 const name = specifier.propertyName || specifier.name;
                 if (name.text) {
-                    if (isShorthandAmbientModuleSymbol(moduleSymbol)) {
+                    if (isUntypedModuleSymbol(moduleSymbol)) {
                         return moduleSymbol;
                     }
 
@@ -1365,8 +1365,9 @@ namespace ts {
             }
 
             const isRelative = isExternalModuleNameRelative(moduleName);
+            const quotedName = '"' + moduleName + '"';
             if (!isRelative) {
-                const symbol = getSymbol(globals, '"' + moduleName + '"', SymbolFlags.ValueModule);
+                const symbol = getSymbol(globals, quotedName, SymbolFlags.ValueModule);
                 if (symbol) {
                     // merged symbol is module declaration symbol combined with all augmentations
                     return getMergedSymbol(symbol);
@@ -1395,6 +1396,28 @@ namespace ts {
                 }
             }
 
+             // May be an untyped module. If so, ignore resolutionDiagnostic.
+            if (!isRelative && resolvedModule && !extensionIsTypeScript(resolvedModule.extension)) {
+                if (compilerOptions.noImplicitAny) {
+                    if (moduleNotFoundError) {
+                        error(errorNode,
+                            Diagnostics.A_package_for_0_was_found_at_1_but_is_untyped_Because_noImplicitAny_is_enabled_this_package_must_have_a_declaration,
+                            moduleReference,
+                            resolvedModule.resolvedFileName);
+                    }
+                    return undefined;
+                }
+
+                // Create a new symbol to represent the untyped module and store it in globals.
+                // This provides a name to the module. See the test tests/cases/fourslash/untypedModuleImport.ts
+                const newSymbol = createSymbol(SymbolFlags.ValueModule, quotedName);
+                // Module symbols are expected to have 'exports', although since this is an untyped module it can be empty.
+                newSymbol.exports = createMap<Symbol>();
+                // Cache it so subsequent accesses will return the same module.
+                globals[quotedName] = newSymbol;
+                return newSymbol;
+            }
+
             if (moduleNotFoundError) {
                 // report errors only if it was requested
                 if (resolutionDiagnostic) {
@@ -3462,7 +3485,7 @@ namespace ts {
         function getTypeOfFuncClassEnumModule(symbol: Symbol): Type {
             const links = getSymbolLinks(symbol);
             if (!links.type) {
-                if (symbol.valueDeclaration.kind === SyntaxKind.ModuleDeclaration && isShorthandAmbientModuleSymbol(symbol)) {
+                if (symbol.flags & SymbolFlags.Module && isUntypedModuleSymbol(symbol)) {
                     links.type = anyType;
                 }
                 else {
@@ -19011,7 +19034,7 @@ namespace ts {
 
         function moduleExportsSomeValue(moduleReferenceExpression: Expression): boolean {
             let moduleSymbol = resolveExternalModuleName(moduleReferenceExpression.parent, moduleReferenceExpression);
-            if (!moduleSymbol || isShorthandAmbientModuleSymbol(moduleSymbol)) {
+            if (!moduleSymbol || isUntypedModuleSymbol(moduleSymbol)) {
                 // If the module is not found or is shorthand, assume that it may export a value.
                 return true;
             }
@@ -19512,7 +19535,7 @@ namespace ts {
                             (typeReferenceDirectives || (typeReferenceDirectives = [])).push(typeReferenceDirective);
                         }
                         else {
-                            // found at least one entry that does not originate from type reference directive 
+                            // found at least one entry that does not originate from type reference directive
                             return undefined;
                         }
                     }
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 0580f7db541e3..1c14d005cb222 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -2869,6 +2869,10 @@
         "category": "Error",
         "code": 6143
     },
+    "A package for '{0}' was found at '{1}', but is untyped. Because '--noImplicitAny' is enabled, this package must have a declaration.": {
+        "category": "Error",
+        "code": 6144
+    },
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index fab35141ba4af..9e89644f4f18e 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1324,6 +1324,7 @@ namespace ts {
                     // - it's not a top level JavaScript module that exceeded the search max
                     const elideImport = isJsFileFromNodeModules && currentNodeModulesDepth > maxNodeModuleJsDepth;
                     // Don't add the file if it has a bad extension (e.g. 'tsx' if we don't have '--allowJs')
+                    // This may still end up being an untyped module -- the file won't be included but imports will be allowed.
                     const shouldAddFile = resolvedFileName && !getResolutionDiagnostic(options, resolution) && !options.noResolve && i < file.imports.length && !elideImport;
 
                     if (elideImport) {
@@ -1571,8 +1572,9 @@ namespace ts {
 
     /* @internal */
     /**
-     * Returns a DiagnosticMessage if we can't use a resolved module due to its extension.
+     * Returns a DiagnosticMessage if we won't include a resolved module due to its extension.
      * The DiagnosticMessage's parameters are the imported module name, and the filename it resolved to.
+     * This returns a diagnostic even if the module will be an untyped module.
      */
     export function getResolutionDiagnostic(options: CompilerOptions, { extension }: ResolvedModule): DiagnosticMessage | undefined {
         switch (extension) {
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 3da6cf7aa3713..bbffdd470d790 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -406,8 +406,9 @@ namespace ts {
             ((<ModuleDeclaration>node).name.kind === SyntaxKind.StringLiteral || isGlobalScopeAugmentation(<ModuleDeclaration>node));
     }
 
-    export function isShorthandAmbientModuleSymbol(moduleSymbol: Symbol): boolean {
-        return isShorthandAmbientModule(moduleSymbol.valueDeclaration);
+    /** Given a symbol for a module, checks that it is either an untyped import or a shorthand ambient module. */
+    export function isUntypedModuleSymbol(moduleSymbol: Symbol): boolean {
+        return !moduleSymbol.valueDeclaration || isShorthandAmbientModule(moduleSymbol.valueDeclaration);
     }
 
     function isShorthandAmbientModule(node: Node): boolean {
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index 47b76793af6af..17e67b053a3ee 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -1108,22 +1108,7 @@ namespace Harness {
                     const option = getCommandLineOption(name);
                     if (option) {
                         const errors: ts.Diagnostic[] = [];
-                        switch (option.type) {
-                            case "boolean":
-                                options[option.name] = value.toLowerCase() === "true";
-                                break;
-                            case "string":
-                                options[option.name] = value;
-                                break;
-                            // If not a primitive, the possible types are specified in what is effectively a map of options.
-                            case "list":
-                                options[option.name] = ts.parseListTypeOption(<ts.CommandLineOptionOfListType>option, value, errors);
-                                break;
-                            default:
-                                options[option.name] = ts.parseCustomTypeOption(<ts.CommandLineOptionOfCustomType>option, value, errors);
-                                break;
-                        }
-
+                        options[option.name] = optionValue(option, value, errors);
                         if (errors.length > 0) {
                             throw new Error(`Unknown value '${value}' for compiler option '${name}'.`);
                         }
@@ -1135,6 +1120,27 @@ namespace Harness {
             }
         }
 
+        function optionValue(option: ts.CommandLineOption, value: string, errors: ts.Diagnostic[]): any {
+            switch (option.type) {
+                case "boolean":
+                    return value.toLowerCase() === "true";
+                case "string":
+                    return value;
+                case "number": {
+                    const number = parseInt(value, 10);
+                    if (isNaN(number)) {
+                        throw new Error(`Value must be a number, got: ${JSON.stringify(value)}`);
+                    }
+                    return number;
+                }
+                // If not a primitive, the possible types are specified in what is effectively a map of options.
+                case "list":
+                    return ts.parseListTypeOption(<ts.CommandLineOptionOfListType>option, value, errors);
+                default:
+                    return ts.parseCustomTypeOption(<ts.CommandLineOptionOfCustomType>option, value, errors);
+            }
+        }
+
         export interface TestFile {
             unitName: string;
             content: string;
diff --git a/tests/baselines/reference/untypedModuleImport.js b/tests/baselines/reference/untypedModuleImport.js
new file mode 100644
index 0000000000000..e3548856411ee
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport.js
@@ -0,0 +1,37 @@
+//// [tests/cases/conformance/moduleResolution/untypedModuleImport.ts] ////
+
+//// [index.js]
+// This tests that importing from a JS file globally works in an untyped way.
+// (Assuming we don't have `--noImplicitAny` or `--allowJs`.)
+
+This file is not processed.
+
+//// [a.ts]
+import * as foo from "foo";
+foo.bar();
+
+//// [b.ts]
+import foo = require("foo");
+foo();
+
+//// [c.ts]
+import foo, { bar } from "foo";
+import "./a";
+import "./b";
+foo(bar());
+
+
+//// [a.js]
+"use strict";
+var foo = require("foo");
+foo.bar();
+//// [b.js]
+"use strict";
+var foo = require("foo");
+foo();
+//// [c.js]
+"use strict";
+var foo_1 = require("foo");
+require("./a");
+require("./b");
+foo_1["default"](foo_1.bar());
diff --git a/tests/baselines/reference/untypedModuleImport.symbols b/tests/baselines/reference/untypedModuleImport.symbols
new file mode 100644
index 0000000000000..2cc04ed6efab2
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport.symbols
@@ -0,0 +1,25 @@
+=== /c.ts ===
+import foo, { bar } from "foo";
+>foo : Symbol(foo, Decl(c.ts, 0, 6))
+>bar : Symbol(bar, Decl(c.ts, 0, 13))
+
+import "./a";
+import "./b";
+foo(bar());
+>foo : Symbol(foo, Decl(c.ts, 0, 6))
+>bar : Symbol(bar, Decl(c.ts, 0, 13))
+
+=== /a.ts ===
+import * as foo from "foo";
+>foo : Symbol(foo, Decl(a.ts, 0, 6))
+
+foo.bar();
+>foo : Symbol(foo, Decl(a.ts, 0, 6))
+
+=== /b.ts ===
+import foo = require("foo");
+>foo : Symbol(foo, Decl(b.ts, 0, 0))
+
+foo();
+>foo : Symbol(foo, Decl(b.ts, 0, 0))
+
diff --git a/tests/baselines/reference/untypedModuleImport.types b/tests/baselines/reference/untypedModuleImport.types
new file mode 100644
index 0000000000000..8a0c7e97ede11
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport.types
@@ -0,0 +1,31 @@
+=== /c.ts ===
+import foo, { bar } from "foo";
+>foo : any
+>bar : any
+
+import "./a";
+import "./b";
+foo(bar());
+>foo(bar()) : any
+>foo : any
+>bar() : any
+>bar : any
+
+=== /a.ts ===
+import * as foo from "foo";
+>foo : any
+
+foo.bar();
+>foo.bar() : any
+>foo.bar : any
+>foo : any
+>bar : any
+
+=== /b.ts ===
+import foo = require("foo");
+>foo : any
+
+foo();
+>foo() : any
+>foo : any
+
diff --git a/tests/baselines/reference/untypedModuleImport_allowJs.js b/tests/baselines/reference/untypedModuleImport_allowJs.js
new file mode 100644
index 0000000000000..8ca5115a386e2
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport_allowJs.js
@@ -0,0 +1,16 @@
+//// [tests/cases/conformance/moduleResolution/untypedModuleImport_allowJs.ts] ////
+
+//// [index.js]
+// Same as untypedModuleImport.ts but with --allowJs, so the package will actually be typed.
+
+exports.default = { bar() { return 0; } }
+
+//// [a.ts]
+import foo from "foo";
+foo.bar();
+
+
+//// [a.js]
+"use strict";
+var foo_1 = require("foo");
+foo_1["default"].bar();
diff --git a/tests/baselines/reference/untypedModuleImport_allowJs.symbols b/tests/baselines/reference/untypedModuleImport_allowJs.symbols
new file mode 100644
index 0000000000000..d660e8116309d
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport_allowJs.symbols
@@ -0,0 +1,17 @@
+=== /a.ts ===
+import foo from "foo";
+>foo : Symbol(foo, Decl(a.ts, 0, 6))
+
+foo.bar();
+>foo.bar : Symbol(bar, Decl(index.js, 2, 19))
+>foo : Symbol(foo, Decl(a.ts, 0, 6))
+>bar : Symbol(bar, Decl(index.js, 2, 19))
+
+=== /node_modules/foo/index.js ===
+// Same as untypedModuleImport.ts but with --allowJs, so the package will actually be typed.
+
+exports.default = { bar() { return 0; } }
+>exports : Symbol(default, Decl(index.js, 0, 0))
+>default : Symbol(default, Decl(index.js, 0, 0))
+>bar : Symbol(bar, Decl(index.js, 2, 19))
+
diff --git a/tests/baselines/reference/untypedModuleImport_allowJs.types b/tests/baselines/reference/untypedModuleImport_allowJs.types
new file mode 100644
index 0000000000000..5a34fdcb646ff
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport_allowJs.types
@@ -0,0 +1,22 @@
+=== /a.ts ===
+import foo from "foo";
+>foo : { bar(): number; }
+
+foo.bar();
+>foo.bar() : number
+>foo.bar : () => number
+>foo : { bar(): number; }
+>bar : () => number
+
+=== /node_modules/foo/index.js ===
+// Same as untypedModuleImport.ts but with --allowJs, so the package will actually be typed.
+
+exports.default = { bar() { return 0; } }
+>exports.default = { bar() { return 0; } } : { bar(): number; }
+>exports.default : any
+>exports : any
+>default : any
+>{ bar() { return 0; } } : { bar(): number; }
+>bar : () => number
+>0 : 0
+
diff --git a/tests/baselines/reference/untypedModuleImport_noImplicitAny.errors.txt b/tests/baselines/reference/untypedModuleImport_noImplicitAny.errors.txt
new file mode 100644
index 0000000000000..7f846c1cd2e7f
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport_noImplicitAny.errors.txt
@@ -0,0 +1,13 @@
+/a.ts(1,22): error TS6144: A package for 'foo' was found at '/node_modules/foo/index.js', but is untyped. Because '--noImplicitAny' is enabled, this package must have a declaration.
+
+
+==== /a.ts (1 errors) ====
+    import * as foo from "foo";
+                         ~~~~~
+!!! error TS6144: A package for 'foo' was found at '/node_modules/foo/index.js', but is untyped. Because '--noImplicitAny' is enabled, this package must have a declaration.
+    
+==== /node_modules/foo/index.js (0 errors) ====
+    // This tests that `--noImplicitAny` disables untyped modules.
+    
+    This file is not processed.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/untypedModuleImport_noImplicitAny.js b/tests/baselines/reference/untypedModuleImport_noImplicitAny.js
new file mode 100644
index 0000000000000..ab1e1940e3625
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport_noImplicitAny.js
@@ -0,0 +1,13 @@
+//// [tests/cases/conformance/moduleResolution/untypedModuleImport_noImplicitAny.ts] ////
+
+//// [index.js]
+// This tests that `--noImplicitAny` disables untyped modules.
+
+This file is not processed.
+
+//// [a.ts]
+import * as foo from "foo";
+
+
+//// [a.js]
+"use strict";
diff --git a/tests/baselines/reference/untypedModuleImport_noLocalImports.errors.txt b/tests/baselines/reference/untypedModuleImport_noLocalImports.errors.txt
new file mode 100644
index 0000000000000..0f376ea61ec20
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport_noLocalImports.errors.txt
@@ -0,0 +1,13 @@
+/a.ts(1,22): error TS6143: Module './foo' was resolved to '/foo.js', but '--allowJs' is not set.
+
+
+==== /a.ts (1 errors) ====
+    import * as foo from "./foo";
+                         ~~~~~~~
+!!! error TS6143: Module './foo' was resolved to '/foo.js', but '--allowJs' is not set.
+    
+==== /foo.js (0 errors) ====
+    // This tests that untyped module imports don't happen with local imports.
+    
+    This file is not processed.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/untypedModuleImport_noLocalImports.js b/tests/baselines/reference/untypedModuleImport_noLocalImports.js
new file mode 100644
index 0000000000000..8fa67a0857f21
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport_noLocalImports.js
@@ -0,0 +1,13 @@
+//// [tests/cases/conformance/moduleResolution/untypedModuleImport_noLocalImports.ts] ////
+
+//// [foo.js]
+// This tests that untyped module imports don't happen with local imports.
+
+This file is not processed.
+
+//// [a.ts]
+import * as foo from "./foo";
+
+
+//// [a.js]
+"use strict";
diff --git a/tests/baselines/reference/untypedModuleImport_vsAmbient.js b/tests/baselines/reference/untypedModuleImport_vsAmbient.js
new file mode 100644
index 0000000000000..080cd4433754b
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport_vsAmbient.js
@@ -0,0 +1,23 @@
+//// [tests/cases/conformance/moduleResolution/untypedModuleImport_vsAmbient.ts] ////
+
+//// [index.js]
+// This tests that an ambient module declaration overrides an untyped import.
+
+This file is not processed.
+
+//// [declarations.d.ts]
+declare module "foo" {
+    export const x: number;
+}
+
+//// [a.ts]
+/// <reference path="./declarations.d.ts" />
+import { x } from "foo";
+x;
+
+
+//// [a.js]
+"use strict";
+/// <reference path="./declarations.d.ts" />
+var foo_1 = require("foo");
+foo_1.x;
diff --git a/tests/baselines/reference/untypedModuleImport_vsAmbient.symbols b/tests/baselines/reference/untypedModuleImport_vsAmbient.symbols
new file mode 100644
index 0000000000000..8def3c6a09b6c
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport_vsAmbient.symbols
@@ -0,0 +1,14 @@
+=== /a.ts ===
+/// <reference path="./declarations.d.ts" />
+import { x } from "foo";
+>x : Symbol(x, Decl(a.ts, 1, 8))
+
+x;
+>x : Symbol(x, Decl(a.ts, 1, 8))
+
+=== /declarations.d.ts ===
+declare module "foo" {
+    export const x: number;
+>x : Symbol(x, Decl(declarations.d.ts, 1, 16))
+}
+
diff --git a/tests/baselines/reference/untypedModuleImport_vsAmbient.types b/tests/baselines/reference/untypedModuleImport_vsAmbient.types
new file mode 100644
index 0000000000000..58b0eabefdfe3
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport_vsAmbient.types
@@ -0,0 +1,14 @@
+=== /a.ts ===
+/// <reference path="./declarations.d.ts" />
+import { x } from "foo";
+>x : number
+
+x;
+>x : number
+
+=== /declarations.d.ts ===
+declare module "foo" {
+    export const x: number;
+>x : number
+}
+
diff --git a/tests/cases/conformance/moduleResolution/untypedModuleImport.ts b/tests/cases/conformance/moduleResolution/untypedModuleImport.ts
new file mode 100644
index 0000000000000..2ea07db3ee496
--- /dev/null
+++ b/tests/cases/conformance/moduleResolution/untypedModuleImport.ts
@@ -0,0 +1,21 @@
+// @noImplicitReferences: true
+// @currentDirectory: /
+// This tests that importing from a JS file globally works in an untyped way.
+// (Assuming we don't have `--noImplicitAny` or `--allowJs`.)
+
+// @filename: /node_modules/foo/index.js
+This file is not processed.
+
+// @filename: /a.ts
+import * as foo from "foo";
+foo.bar();
+
+// @filename: /b.ts
+import foo = require("foo");
+foo();
+
+// @filename: /c.ts
+import foo, { bar } from "foo";
+import "./a";
+import "./b";
+foo(bar());
diff --git a/tests/cases/conformance/moduleResolution/untypedModuleImport_allowJs.ts b/tests/cases/conformance/moduleResolution/untypedModuleImport_allowJs.ts
new file mode 100644
index 0000000000000..fe509189d9667
--- /dev/null
+++ b/tests/cases/conformance/moduleResolution/untypedModuleImport_allowJs.ts
@@ -0,0 +1,12 @@
+// @noImplicitReferences: true
+// @currentDirectory: /
+// @allowJs: true
+// @maxNodeModuleJsDepth: 1
+// Same as untypedModuleImport.ts but with --allowJs, so the package will actually be typed.
+
+// @filename: /node_modules/foo/index.js
+exports.default = { bar() { return 0; } }
+
+// @filename: /a.ts
+import foo from "foo";
+foo.bar();
diff --git a/tests/cases/conformance/moduleResolution/untypedModuleImport_noImplicitAny.ts b/tests/cases/conformance/moduleResolution/untypedModuleImport_noImplicitAny.ts
new file mode 100644
index 0000000000000..1aee7c069dedf
--- /dev/null
+++ b/tests/cases/conformance/moduleResolution/untypedModuleImport_noImplicitAny.ts
@@ -0,0 +1,10 @@
+// @noImplicitReferences: true
+// @currentDirectory: /
+// @noImplicitAny: true
+// This tests that `--noImplicitAny` disables untyped modules.
+
+// @filename: /node_modules/foo/index.js
+This file is not processed.
+
+// @filename: /a.ts
+import * as foo from "foo";
diff --git a/tests/cases/conformance/moduleResolution/untypedModuleImport_noLocalImports.ts b/tests/cases/conformance/moduleResolution/untypedModuleImport_noLocalImports.ts
new file mode 100644
index 0000000000000..8313628e6d7ee
--- /dev/null
+++ b/tests/cases/conformance/moduleResolution/untypedModuleImport_noLocalImports.ts
@@ -0,0 +1,9 @@
+// @noImplicitReferences: true
+// @currentDirectory: /
+// This tests that untyped module imports don't happen with local imports.
+
+// @filename: /foo.js
+This file is not processed.
+
+// @filename: /a.ts
+import * as foo from "./foo";
diff --git a/tests/cases/conformance/moduleResolution/untypedModuleImport_vsAmbient.ts b/tests/cases/conformance/moduleResolution/untypedModuleImport_vsAmbient.ts
new file mode 100644
index 0000000000000..e157772a5edad
--- /dev/null
+++ b/tests/cases/conformance/moduleResolution/untypedModuleImport_vsAmbient.ts
@@ -0,0 +1,16 @@
+// @noImplicitReferences: true
+// @currentDirectory: /
+// This tests that an ambient module declaration overrides an untyped import.
+
+// @filename: /node_modules/foo/index.js
+This file is not processed.
+
+// @filename: /declarations.d.ts
+declare module "foo" {
+    export const x: number;
+}
+
+// @filename: /a.ts
+/// <reference path="./declarations.d.ts" />
+import { x } from "foo";
+x;
diff --git a/tests/cases/fourslash/untypedModuleImport.ts b/tests/cases/fourslash/untypedModuleImport.ts
new file mode 100644
index 0000000000000..3fd209d480d31
--- /dev/null
+++ b/tests/cases/fourslash/untypedModuleImport.ts
@@ -0,0 +1,22 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: node_modules/foo/index.js
+////{}
+
+// @Filename: a.ts
+////import /*foo*/[|foo|] from /*fooModule*/"foo";
+////[|foo|]();
+
+goTo.file("a.ts");
+debug.printErrorList();
+verify.numberOfErrorsInCurrentFile(0);
+
+goTo.marker("fooModule");
+verify.goToDefinitionIs([]);
+verify.quickInfoIs('module "foo"');
+verify.referencesAre([])
+
+goTo.marker("foo");
+verify.goToDefinitionIs([]);
+verify.quickInfoIs("import foo");
+verify.rangesReferenceEachOther();

From ca09ef4499d845c0f9d44df898ccd3b842391d24 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 27 Oct 2016 06:36:39 -0700
Subject: [PATCH 098/224] Simplify for loops in fourslash.ts

---
 src/compiler/core.ts     |   7 ++
 src/harness/fourslash.ts | 141 +++++++++++++--------------------------
 2 files changed, 55 insertions(+), 93 deletions(-)

diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index c143caa974bfb..7d3949e981fb4 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -124,6 +124,13 @@ namespace ts {
         return undefined;
     }
 
+    export function zip<T, U>(arrayA: T[], arrayB: U[], callback: (a: T, b: U, index: number) => void): void {
+        Debug.assert(arrayA.length === arrayB.length);
+        for (let i = 0; i < arrayA.length; i++) {
+            callback(arrayA[i], arrayB[i], i);
+        }
+    }
+
     /**
      * Iterates through `array` by index and performs the callback on each element of array until the callback
      * returns a falsey value, then returns false.
diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index e9fa5d6be2e80..b50c12b816f54 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -438,9 +438,8 @@ namespace FourSlash {
         private getAllDiagnostics(): ts.Diagnostic[] {
             const diagnostics: ts.Diagnostic[] = [];
 
-            const fileNames = this.languageServiceAdapterHost.getFilenames();
-            for (let i = 0, n = fileNames.length; i < n; i++) {
-                diagnostics.push.apply(this.getDiagnostics(fileNames[i]));
+            for (const fileName of this.languageServiceAdapterHost.getFilenames()) {
+                diagnostics.push.apply(this.getDiagnostics(fileName));
             }
 
             return diagnostics;
@@ -580,12 +579,12 @@ namespace FourSlash {
                 this.raiseError(`goToDefinitions failed - expected to find ${endMarkers.length} definitions but got ${definitions.length}`);
             }
 
-            for (let i = 0; i < endMarkers.length; i++) {
-                const marker = this.getMarkerByName(endMarkers[i]), definition = definitions[i];
+            ts.zip(endMarkers, definitions, (endMarker, definition, i) => {
+                const marker = this.getMarkerByName(endMarker);
                 if (marker.fileName !== definition.fileName || marker.position !== definition.textSpan.start) {
                     this.raiseError(`goToDefinition failed for definition ${i}: expected ${marker.fileName} at ${marker.position}, got ${definition.fileName} at ${definition.textSpan.start}`);
                 }
-            }
+            });
         }
 
         public verifyGetEmitOutputForCurrentFile(expected: string): void {
@@ -602,10 +601,10 @@ namespace FourSlash {
         public verifyGetEmitOutputContentsForCurrentFile(expected: ts.OutputFile[]): void {
             const emit = this.languageService.getEmitOutput(this.activeFile.fileName);
             assert.equal(emit.outputFiles.length, expected.length, "Number of emit output files");
-            for (let i = 0; i < emit.outputFiles.length; i++) {
-                assert.equal(emit.outputFiles[i].name, expected[i].name, "FileName");
-                assert.equal(emit.outputFiles[i].text, expected[i].text, "Content");
-            }
+            ts.zip(emit.outputFiles, expected, (outputFile, expected) => {
+                assert.equal(outputFile.name, expected.name, "FileName");
+                assert.equal(outputFile.text, expected.text, "Content");
+            });
         }
 
         public verifyMemberListContains(symbol: string, text?: string, documentation?: string, kind?: string) {
@@ -668,9 +667,9 @@ namespace FourSlash {
 
             const entries = this.getCompletionListAtCaret().entries;
             assert.isTrue(items.length <= entries.length, `Amount of expected items in completion list [ ${items.length} ] is greater than actual number of items in list [ ${entries.length} ]`);
-            for (let i = 0; i < items.length; i++) {
-                assert.equal(entries[i].name, items[i], `Unexpected item in completion list`);
-            }
+            ts.zip(entries, items, (entry, item) => {
+                assert.equal(entry.name, item, `Unexpected item in completion list`);
+            });
         }
 
         public noItemsWithSameNameButDifferentKind(): void {
@@ -692,15 +691,7 @@ namespace FourSlash {
                 this.raiseError("Member list is empty at Caret");
             }
             else if ((members && members.entries.length !== 0) && !negative) {
-
-                let errorMsg = "\n" + "Member List contains: [" + members.entries[0].name;
-                for (let i = 1; i < members.entries.length; i++) {
-                    errorMsg += ", " + members.entries[i].name;
-                }
-                errorMsg += "]\n";
-
-                this.raiseError("Member list is not empty at Caret: " + errorMsg);
-
+                this.raiseError(`Member list is not empty at Caret:\nMember List contains: ${stringify(members.entries.map(e => e.name))}`);
             }
         }
 
@@ -710,13 +701,8 @@ namespace FourSlash {
                 this.raiseError("Completion list is empty at caret at position " + this.activeFile.fileName + " " + this.currentCaretPosition);
             }
             else if (completions && completions.entries.length !== 0 && !negative) {
-                let errorMsg = "\n" + "Completion List contains: [" + completions.entries[0].name;
-                for (let i = 1; i < completions.entries.length; i++) {
-                    errorMsg += ", " + completions.entries[i].name;
-                }
-                errorMsg += "]\n";
-
-                this.raiseError("Completion list is not empty at caret at position " + this.activeFile.fileName + " " + this.currentCaretPosition + errorMsg);
+                this.raiseError(`Completion list is not empty at caret at position ${this.activeFile.fileName} ${this.currentCaretPosition}\n` +
+                    `Completion List contains: ${stringify(completions.entries.map(e => e.name))}`);
             }
         }
 
@@ -890,8 +876,7 @@ namespace FourSlash {
         }
 
         private verifyReferencesWorker(references: ts.ReferenceEntry[], fileName: string, start: number, end: number, isWriteAccess?: boolean, isDefinition?: boolean) {
-            for (let i = 0; i < references.length; i++) {
-                const reference = references[i];
+            for (const reference of references) {
                 if (reference && reference.fileName === fileName && reference.textSpan.start === start && ts.textSpanEnd(reference.textSpan) === end) {
                     if (typeof isWriteAccess !== "undefined" && reference.isWriteAccess !== isWriteAccess) {
                         this.raiseError(`verifyReferencesAtPositionListContains failed - item isWriteAccess value does not match, actual: ${reference.isWriteAccess}, expected: ${isWriteAccess}.`);
@@ -1008,16 +993,11 @@ namespace FourSlash {
                 ranges = ranges.sort((r1, r2) => r1.start - r2.start);
                 references = references.sort((r1, r2) => r1.textSpan.start - r2.textSpan.start);
 
-                for (let i = 0, n = ranges.length; i < n; i++) {
-                    const reference = references[i];
-                    const range = ranges[i];
-
-                    if (reference.textSpan.start !== range.start ||
-                        ts.textSpanEnd(reference.textSpan) !== range.end) {
-
+                ts.zip(references, ranges, (reference, range) => {
+                    if (reference.textSpan.start !== range.start || ts.textSpanEnd(reference.textSpan) !== range.end) {
                         this.raiseError("Rename location results do not match.\n\nExpected: " + stringify(ranges) + "\n\nActual:" + JSON.stringify(references));
                     }
-                }
+                });
             }
             else {
                 this.raiseError("Expected rename to succeed, but it actually failed.");
@@ -1247,8 +1227,7 @@ namespace FourSlash {
             const emitFiles: FourSlashFile[] = [];  // List of FourSlashFile that has emitThisFile flag on
 
             const allFourSlashFiles = this.testData.files;
-            for (let idx = 0; idx < allFourSlashFiles.length; idx++) {
-                const file = allFourSlashFiles[idx];
+            for (const file of allFourSlashFiles) {
                 if (file.fileOptions[metadataOptionNames.emitThisFile] === "true") {
                     // Find a file with the flag emitThisFile turned on
                     emitFiles.push(file);
@@ -1273,8 +1252,8 @@ namespace FourSlash {
                         if (emitOutput.emitSkipped) {
                             resultString += "Diagnostics:" + Harness.IO.newLine();
                             const diagnostics = ts.getPreEmitDiagnostics(this.languageService.getProgram());
-                            for (let i = 0, n = diagnostics.length; i < n; i++) {
-                                resultString += "  " + diagnostics[0].messageText + Harness.IO.newLine();
+                            for (const diagnostic of diagnostics) {
+                                resultString += "  " + diagnostic.messageText + Harness.IO.newLine();
                             }
                         }
 
@@ -1340,8 +1319,7 @@ namespace FourSlash {
         }
 
         public printCurrentFileState(makeWhitespaceVisible = false, makeCaretVisible = true) {
-            for (let i = 0; i < this.testData.files.length; i++) {
-                const file = this.testData.files[i];
+            for (const file of this.testData.files) {
                 const active = (this.activeFile === file);
                 Harness.IO.log(`=== Script (${file.fileName}) ${(active ? "(active, cursor at |)" : "")} ===`);
                 let content = this.getFileContent(file.fileName);
@@ -1576,10 +1554,10 @@ namespace FourSlash {
             edits = edits.sort((a, b) => a.span.start - b.span.start);
             // Get a snapshot of the content of the file so we can make sure any formatting edits didn't destroy non-whitespace characters
             const oldContent = this.getFileContent(this.activeFile.fileName);
-            for (let j = 0; j < edits.length; j++) {
-                this.languageServiceAdapterHost.editScript(fileName, edits[j].span.start + runningOffset, ts.textSpanEnd(edits[j].span) + runningOffset, edits[j].newText);
-                this.updateMarkersForEdit(fileName, edits[j].span.start + runningOffset, ts.textSpanEnd(edits[j].span) + runningOffset, edits[j].newText);
-                const change = (edits[j].span.start - ts.textSpanEnd(edits[j].span)) + edits[j].newText.length;
+            for (const edit of edits) {
+                this.languageServiceAdapterHost.editScript(fileName, edit.span.start + runningOffset, ts.textSpanEnd(edit.span) + runningOffset, edit.newText);
+                this.updateMarkersForEdit(fileName, edit.span.start + runningOffset, ts.textSpanEnd(edit.span) + runningOffset, edit.newText);
+                const change = (edit.span.start - ts.textSpanEnd(edit.span)) + edit.newText.length;
                 runningOffset += change;
                 // TODO: Consider doing this at least some of the time for higher fidelity. Currently causes a failure (bug 707150)
                 // this.languageService.getScriptLexicalStructure(fileName);
@@ -1913,10 +1891,7 @@ namespace FourSlash {
                     jsonMismatchString());
             }
 
-            for (let i = 0; i < expected.length; i++) {
-                const expectedClassification = expected[i];
-                const actualClassification = actual[i];
-
+            ts.zip(expected, actual, (expectedClassification, actualClassification) => {
                 const expectedType: string = (<any>ts.ClassificationTypeNames)[expectedClassification.classificationType];
                 if (expectedType !== actualClassification.classificationType) {
                     this.raiseError("verifyClassifications failed - expected classifications type to be " +
@@ -1946,7 +1921,7 @@ namespace FourSlash {
                         actualText +
                         jsonMismatchString());
                 }
-            }
+            });
 
             function jsonMismatchString() {
                 return Harness.IO.newLine() +
@@ -1991,13 +1966,11 @@ namespace FourSlash {
                 this.raiseError(`verifyOutliningSpans failed - expected total spans to be ${spans.length}, but was ${actual.length}`);
             }
 
-            for (let i = 0; i < spans.length; i++) {
-                const expectedSpan = spans[i];
-                const actualSpan = actual[i];
+            ts.zip(spans, actual, (expectedSpan, actualSpan, i) => {
                 if (expectedSpan.start !== actualSpan.textSpan.start || expectedSpan.end !== ts.textSpanEnd(actualSpan.textSpan)) {
                     this.raiseError(`verifyOutliningSpans failed - span ${(i + 1)} expected: (${expectedSpan.start},${expectedSpan.end}),  actual: (${actualSpan.textSpan.start},${ts.textSpanEnd(actualSpan.textSpan)})`);
                 }
-            }
+            });
         }
 
         public verifyTodoComments(descriptors: string[], spans: TextSpan[]) {
@@ -2008,15 +1981,13 @@ namespace FourSlash {
                 this.raiseError(`verifyTodoComments failed - expected total spans to be ${spans.length}, but was ${actual.length}`);
             }
 
-            for (let i = 0; i < spans.length; i++) {
-                const expectedSpan = spans[i];
-                const actualComment = actual[i];
+            ts.zip(spans, actual, (expectedSpan, actualComment, i) => {
                 const actualCommentSpan = ts.createTextSpan(actualComment.position, actualComment.message.length);
 
                 if (expectedSpan.start !== actualCommentSpan.start || expectedSpan.end !== ts.textSpanEnd(actualCommentSpan)) {
                     this.raiseError(`verifyOutliningSpans failed - span ${(i + 1)} expected: (${expectedSpan.start},${expectedSpan.end}),  actual: (${actualCommentSpan.start},${ts.textSpanEnd(actualCommentSpan)})`);
                 }
-            }
+            });
         }
 
         private getCodeFixes(errorCode?: number) {
@@ -2163,11 +2134,9 @@ namespace FourSlash {
         public verifyNavigationItemsCount(expected: number, searchValue: string, matchKind?: string, fileName?: string) {
             const items = this.languageService.getNavigateToItems(searchValue, /*maxResultCount*/ undefined, fileName);
             let actual = 0;
-            let item: ts.NavigateToItem;
 
             // Count only the match that match the same MatchKind
-            for (let i = 0; i < items.length; i++) {
-                item = items[i];
+            for (const item of items) {
                 if (!matchKind || item.matchKind === matchKind) {
                     actual++;
                 }
@@ -2195,8 +2164,7 @@ namespace FourSlash {
                 this.raiseError("verifyNavigationItemsListContains failed - found 0 navigation items, expected at least one.");
             }
 
-            for (let i = 0; i < items.length; i++) {
-                const item = items[i];
+            for (const item of items) {
                 if (item && item.name === name && item.kind === kind &&
                     (matchKind === undefined || item.matchKind === matchKind) &&
                     (fileName === undefined || item.fileName === fileName) &&
@@ -2247,24 +2215,16 @@ namespace FourSlash {
 
         public printNavigationItems(searchValue: string) {
             const items = this.languageService.getNavigateToItems(searchValue);
-            const length = items && items.length;
-
-            Harness.IO.log(`NavigationItems list (${length} items)`);
-
-            for (let i = 0; i < length; i++) {
-                const item = items[i];
+            Harness.IO.log(`NavigationItems list (${items.length} items)`);
+            for (const item of items) {
                 Harness.IO.log(`name: ${item.name}, kind: ${item.kind}, parentName: ${item.containerName}, fileName: ${item.fileName}`);
             }
         }
 
         public printNavigationBar() {
             const items = this.languageService.getNavigationBarItems(this.activeFile.fileName);
-            const length = items && items.length;
-
-            Harness.IO.log(`Navigation bar (${length} items)`);
-
-            for (let i = 0; i < length; i++) {
-                const item = items[i];
+            Harness.IO.log(`Navigation bar (${items.length} items)`);
+            for (const item of items) {
                 Harness.IO.log(`${repeatString(item.indent, " ")}name: ${item.text}, kind: ${item.kind}, childItems: ${item.childItems.map(child => child.text)}`);
             }
         }
@@ -2385,8 +2345,7 @@ namespace FourSlash {
         }
 
         private assertItemInCompletionList(items: ts.CompletionEntry[], name: string, text?: string, documentation?: string, kind?: string, spanIndex?: number) {
-            for (let i = 0; i < items.length; i++) {
-                const item = items[i];
+            for (const item of items) {
                 if (item.name === name) {
                     if (documentation != undefined || text !== undefined) {
                         const details = this.getCompletionEntryDetails(item.name);
@@ -2435,20 +2394,17 @@ namespace FourSlash {
                 name = name.indexOf("/") === -1 ? (this.basePath + "/" + name) : name;
 
                 const availableNames: string[] = [];
-                let foundIt = false;
-                for (let i = 0; i < this.testData.files.length; i++) {
-                    const fn = this.testData.files[i].fileName;
+                result = ts.forEach(this.testData.files, file => {
+                    const fn = file.fileName;
                     if (fn) {
                         if (fn === name) {
-                            result = this.testData.files[i];
-                            foundIt = true;
-                            break;
+                            return file;
                         }
                         availableNames.push(fn);
                     }
-                }
+                });
 
-                if (!foundIt) {
+                if (!result) {
                     throw new Error(`No test file named "${name}" exists. Available file names are: ${availableNames.join(", ")}`);
                 }
             }
@@ -2549,8 +2505,8 @@ ${code}
 
     function chompLeadingSpace(content: string) {
         const lines = content.split("\n");
-        for (let i = 0; i < lines.length; i++) {
-            if ((lines[i].length !== 0) && (lines[i].charAt(0) !== " ")) {
+        for (const line of lines) {
+            if ((line.length !== 0) && (line.charAt(0) !== " ")) {
                 return content;
             }
         }
@@ -2588,8 +2544,7 @@ ${code}
             currentFileName = fileName;
         }
 
-        for (let i = 0; i < lines.length; i++) {
-            let line = lines[i];
+        for (let line of lines) {
             const lineLength = line.length;
 
             if (lineLength > 0 && line.charAt(lineLength - 1) === "\r") {

From eb45962e20486984b3193a7cd0f2fc4a4bf6b7c2 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 27 Oct 2016 10:26:46 -0700
Subject: [PATCH 099/224] Rename to zipWith

---
 src/compiler/core.ts     |  2 +-
 src/harness/fourslash.ts | 14 +++++++-------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 7d3949e981fb4..f207cf010e2a5 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -124,7 +124,7 @@ namespace ts {
         return undefined;
     }
 
-    export function zip<T, U>(arrayA: T[], arrayB: U[], callback: (a: T, b: U, index: number) => void): void {
+    export function zipWith<T, U>(arrayA: T[], arrayB: U[], callback: (a: T, b: U, index: number) => void): void {
         Debug.assert(arrayA.length === arrayB.length);
         for (let i = 0; i < arrayA.length; i++) {
             callback(arrayA[i], arrayB[i], i);
diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index b50c12b816f54..b008ca653702d 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -579,7 +579,7 @@ namespace FourSlash {
                 this.raiseError(`goToDefinitions failed - expected to find ${endMarkers.length} definitions but got ${definitions.length}`);
             }
 
-            ts.zip(endMarkers, definitions, (endMarker, definition, i) => {
+            ts.zipWith(endMarkers, definitions, (endMarker, definition, i) => {
                 const marker = this.getMarkerByName(endMarker);
                 if (marker.fileName !== definition.fileName || marker.position !== definition.textSpan.start) {
                     this.raiseError(`goToDefinition failed for definition ${i}: expected ${marker.fileName} at ${marker.position}, got ${definition.fileName} at ${definition.textSpan.start}`);
@@ -601,7 +601,7 @@ namespace FourSlash {
         public verifyGetEmitOutputContentsForCurrentFile(expected: ts.OutputFile[]): void {
             const emit = this.languageService.getEmitOutput(this.activeFile.fileName);
             assert.equal(emit.outputFiles.length, expected.length, "Number of emit output files");
-            ts.zip(emit.outputFiles, expected, (outputFile, expected) => {
+            ts.zipWith(emit.outputFiles, expected, (outputFile, expected) => {
                 assert.equal(outputFile.name, expected.name, "FileName");
                 assert.equal(outputFile.text, expected.text, "Content");
             });
@@ -667,7 +667,7 @@ namespace FourSlash {
 
             const entries = this.getCompletionListAtCaret().entries;
             assert.isTrue(items.length <= entries.length, `Amount of expected items in completion list [ ${items.length} ] is greater than actual number of items in list [ ${entries.length} ]`);
-            ts.zip(entries, items, (entry, item) => {
+            ts.zipWith(entries, items, (entry, item) => {
                 assert.equal(entry.name, item, `Unexpected item in completion list`);
             });
         }
@@ -993,7 +993,7 @@ namespace FourSlash {
                 ranges = ranges.sort((r1, r2) => r1.start - r2.start);
                 references = references.sort((r1, r2) => r1.textSpan.start - r2.textSpan.start);
 
-                ts.zip(references, ranges, (reference, range) => {
+                ts.zipWith(references, ranges, (reference, range) => {
                     if (reference.textSpan.start !== range.start || ts.textSpanEnd(reference.textSpan) !== range.end) {
                         this.raiseError("Rename location results do not match.\n\nExpected: " + stringify(ranges) + "\n\nActual:" + JSON.stringify(references));
                     }
@@ -1891,7 +1891,7 @@ namespace FourSlash {
                     jsonMismatchString());
             }
 
-            ts.zip(expected, actual, (expectedClassification, actualClassification) => {
+            ts.zipWith(expected, actual, (expectedClassification, actualClassification) => {
                 const expectedType: string = (<any>ts.ClassificationTypeNames)[expectedClassification.classificationType];
                 if (expectedType !== actualClassification.classificationType) {
                     this.raiseError("verifyClassifications failed - expected classifications type to be " +
@@ -1966,7 +1966,7 @@ namespace FourSlash {
                 this.raiseError(`verifyOutliningSpans failed - expected total spans to be ${spans.length}, but was ${actual.length}`);
             }
 
-            ts.zip(spans, actual, (expectedSpan, actualSpan, i) => {
+            ts.zipWith(spans, actual, (expectedSpan, actualSpan, i) => {
                 if (expectedSpan.start !== actualSpan.textSpan.start || expectedSpan.end !== ts.textSpanEnd(actualSpan.textSpan)) {
                     this.raiseError(`verifyOutliningSpans failed - span ${(i + 1)} expected: (${expectedSpan.start},${expectedSpan.end}),  actual: (${actualSpan.textSpan.start},${ts.textSpanEnd(actualSpan.textSpan)})`);
                 }
@@ -1981,7 +1981,7 @@ namespace FourSlash {
                 this.raiseError(`verifyTodoComments failed - expected total spans to be ${spans.length}, but was ${actual.length}`);
             }
 
-            ts.zip(spans, actual, (expectedSpan, actualComment, i) => {
+            ts.zipWith(spans, actual, (expectedSpan, actualComment, i) => {
                 const actualCommentSpan = ts.createTextSpan(actualComment.position, actualComment.message.length);
 
                 if (expectedSpan.start !== actualCommentSpan.start || expectedSpan.end !== ts.textSpanEnd(actualCommentSpan)) {

From ce099e5374cd0a1b598728fd4aa2dfe6caceeb66 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 27 Oct 2016 11:10:18 -0700
Subject: [PATCH 100/224] Change diagnostic message

---
 src/compiler/checker.ts                                   | 2 +-
 src/compiler/diagnosticMessages.json                      | 8 ++++----
 .../untypedModuleImport_noImplicitAny.errors.txt          | 4 ++--
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index f9c00b5c1587f..4f8f9b3f68c7c 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -1401,7 +1401,7 @@ namespace ts {
                 if (compilerOptions.noImplicitAny) {
                     if (moduleNotFoundError) {
                         error(errorNode,
-                            Diagnostics.A_package_for_0_was_found_at_1_but_is_untyped_Because_noImplicitAny_is_enabled_this_package_must_have_a_declaration,
+                            Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type,
                             moduleReference,
                             resolvedModule.resolvedFileName);
                     }
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 1c14d005cb222..e2a2a4b9a0cf4 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -2869,10 +2869,6 @@
         "category": "Error",
         "code": 6143
     },
-    "A package for '{0}' was found at '{1}', but is untyped. Because '--noImplicitAny' is enabled, this package must have a declaration.": {
-        "category": "Error",
-        "code": 6144
-    },
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005
@@ -2905,6 +2901,10 @@
         "category": "Error",
         "code": 7015
     },
+    "Could not find a declaration file for module '{0}'. '{1}' implicitly has an 'any' type.": {
+        "category": "Error",
+        "code": 7016
+    },
     "Index signature of object type implicitly has an 'any' type.": {
         "category": "Error",
         "code": 7017
diff --git a/tests/baselines/reference/untypedModuleImport_noImplicitAny.errors.txt b/tests/baselines/reference/untypedModuleImport_noImplicitAny.errors.txt
index 7f846c1cd2e7f..349a944deebb2 100644
--- a/tests/baselines/reference/untypedModuleImport_noImplicitAny.errors.txt
+++ b/tests/baselines/reference/untypedModuleImport_noImplicitAny.errors.txt
@@ -1,10 +1,10 @@
-/a.ts(1,22): error TS6144: A package for 'foo' was found at '/node_modules/foo/index.js', but is untyped. Because '--noImplicitAny' is enabled, this package must have a declaration.
+/a.ts(1,22): error TS7016: Could not find a declaration file for module 'foo'. '/node_modules/foo/index.js' implicitly has an 'any' type.
 
 
 ==== /a.ts (1 errors) ====
     import * as foo from "foo";
                          ~~~~~
-!!! error TS6144: A package for 'foo' was found at '/node_modules/foo/index.js', but is untyped. Because '--noImplicitAny' is enabled, this package must have a declaration.
+!!! error TS7016: Could not find a declaration file for module 'foo'. '/node_modules/foo/index.js' implicitly has an 'any' type.
     
 ==== /node_modules/foo/index.js (0 errors) ====
     // This tests that `--noImplicitAny` disables untyped modules.

From 0f8003fb39392b93b94d493ea5925d4e9f320fb5 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 27 Oct 2016 11:33:01 -0700
Subject: [PATCH 101/224] Make `extension` property of `ResolvedModule`
 optional; introduce `ResolvedModuleFull` interface for when the extension is
 provided.

---
 src/compiler/moduleNameResolver.ts        |  2 +-
 src/compiler/program.ts                   | 16 ++++++++--------
 src/compiler/types.ts                     | 23 ++++++++++++++++-------
 src/compiler/utilities.ts                 | 12 ++++--------
 src/harness/unittests/moduleResolution.ts |  6 +++---
 src/server/lsHost.ts                      |  2 +-
 src/services/services.ts                  |  2 +-
 src/services/shims.ts                     |  2 +-
 8 files changed, 35 insertions(+), 30 deletions(-)

diff --git a/src/compiler/moduleNameResolver.ts b/src/compiler/moduleNameResolver.ts
index 1b0a579180270..9e159a356c7c7 100644
--- a/src/compiler/moduleNameResolver.ts
+++ b/src/compiler/moduleNameResolver.ts
@@ -45,7 +45,7 @@ namespace ts {
     }
 
     /** Adds `isExernalLibraryImport` to a Resolved to get a ResolvedModule. */
-    function resolvedModuleFromResolved({ path, extension }: Resolved, isExternalLibraryImport: boolean): ResolvedModule {
+    function resolvedModuleFromResolved({ path, extension }: Resolved, isExternalLibraryImport: boolean): ResolvedModuleFull {
         return { resolvedFileName: path, extension, isExternalLibraryImport };
     }
 
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 6b5a09bfbc3e8..fc481510e8568 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -329,16 +329,16 @@ namespace ts {
         // Map storing if there is emit blocking diagnostics for given input
         const hasEmitBlockingDiagnostics = createFileMap<boolean>(getCanonicalFileName);
 
-        let resolveModuleNamesWorker: (moduleNames: string[], containingFile: string) => ResolvedModule[];
+        let resolveModuleNamesWorker: (moduleNames: string[], containingFile: string) => ResolvedModuleFull[];
         if (host.resolveModuleNames) {
             resolveModuleNamesWorker = (moduleNames, containingFile) => host.resolveModuleNames(moduleNames, containingFile).map(resolved => {
                 // An older host may have omitted extension, in which case we should infer it from the file extension of resolvedFileName.
-                if (!resolved || resolved.extension !== undefined) {
-                    return resolved;
+                if (!resolved || (resolved as ResolvedModuleFull).extension !== undefined) {
+                    return resolved as ResolvedModuleFull;
                 }
-                resolved = clone(resolved);
-                resolved.extension = extensionFromPath(resolved.resolvedFileName);
-                return resolved;
+                const withExtension = clone(resolved) as ResolvedModuleFull;
+                withExtension.extension = extensionFromPath(resolved.resolvedFileName);
+                return withExtension;
             });
         }
         else {
@@ -1294,7 +1294,7 @@ namespace ts {
         function processImportedModules(file: SourceFile) {
             collectExternalModuleReferences(file);
             if (file.imports.length || file.moduleAugmentations.length) {
-                file.resolvedModules = createMap<ResolvedModule>();
+                file.resolvedModules = createMap<ResolvedModuleFull>();
                 const moduleNames = map(concatenate(file.imports, file.moduleAugmentations), getTextOfLiteral);
                 const resolutions = resolveModuleNamesWorker(moduleNames, getNormalizedAbsolutePath(file.fileName, currentDirectory));
                 Debug.assert(resolutions.length === moduleNames.length);
@@ -1571,7 +1571,7 @@ namespace ts {
      * Returns a DiagnosticMessage if we can't use a resolved module due to its extension.
      * The DiagnosticMessage's parameters are the imported module name, and the filename it resolved to.
      */
-    export function getResolutionDiagnostic(options: CompilerOptions, { extension }: ResolvedModule): DiagnosticMessage | undefined {
+    export function getResolutionDiagnostic(options: CompilerOptions, { extension }: ResolvedModuleFull): DiagnosticMessage | undefined {
         switch (extension) {
             case Extension.Ts:
             case Extension.Dts:
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 9034ca32e4e91..419d062bb7f9e 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -423,7 +423,7 @@ namespace ts {
         ThisNodeHasError =   1 << 19, // If the parser encountered an error when parsing the code that created this node
         JavaScriptFile =     1 << 20, // If node was parsed in a JavaScript
         ThisNodeOrAnySubNodesHasError = 1 << 21, // If this node or any of its children had an error
-        HasAggregatedChildData = 1 << 22, // If we've computed data from children and cached it in this node 
+        HasAggregatedChildData = 1 << 22, // If we've computed data from children and cached it in this node
 
         BlockScoped = Let | Const,
 
@@ -2083,7 +2083,7 @@ namespace ts {
         // Stores a mapping 'external module reference text' -> 'resolved file name' | undefined
         // It is used to resolve module names in the checker.
         // Content of this field should never be used directly - use getResolvedModuleFileName/setResolvedModuleFileName functions instead
-        /* @internal */ resolvedModules: Map<ResolvedModule>;
+        /* @internal */ resolvedModules: Map<ResolvedModuleFull>;
         /* @internal */ resolvedTypeReferenceDirectiveNames: Map<ResolvedTypeReferenceDirective>;
         /* @internal */ imports: LiteralExpression[];
         /* @internal */ moduleAugmentations: LiteralExpression[];
@@ -3352,14 +3352,11 @@ namespace ts {
      * Module resolution will pick up tsx/jsx/js files even if '--jsx' and '--allowJs' are turned off.
      * The Program will then filter results based on these flags.
      *
-     * At least one of `resolvedTsFileName` or `resolvedJsFileName` must be defined,
-     * else resolution should just return `undefined` instead of a ResolvedModule.
+     * Prefer to return a `ResolvedModuleFull` so that the file type does not have to be inferred.
      */
     export interface ResolvedModule {
         /** Path of the file the module was resolved to. */
         resolvedFileName: string;
-        /** Extension of resolvedFileName. This must match what's at the end of resolvedFileName. */
-        extension: Extension;
         /**
          * Denotes if 'resolvedFileName' is isExternalLibraryImport and thus should be a proper external module:
          * - be a .d.ts file
@@ -3369,6 +3366,18 @@ namespace ts {
         isExternalLibraryImport?: boolean;
     }
 
+    /**
+     * ResolvedModule with an explicitly provided `extension` property.
+     * Prefer this over `ResolvedModule`.
+     */
+    export interface ResolvedModuleFull extends ResolvedModule {
+        /**
+         * Extension of resolvedFileName. This must match what's at the end of resolvedFileName.
+         * This is optional for backwards-compatibility, but will be added if not provided.
+         */
+        extension: Extension;
+    }
+
     export enum Extension {
         Ts,
         Tsx,
@@ -3379,7 +3388,7 @@ namespace ts {
     }
 
     export interface ResolvedModuleWithFailedLookupLocations {
-        resolvedModule: ResolvedModule | undefined;
+        resolvedModule: ResolvedModuleFull | undefined;
         failedLookupLocations: string[];
     }
 
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 3da6cf7aa3713..6b635e37bc389 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -87,13 +87,13 @@ namespace ts {
         return !!(sourceFile && sourceFile.resolvedModules && sourceFile.resolvedModules[moduleNameText]);
     }
 
-    export function getResolvedModule(sourceFile: SourceFile, moduleNameText: string): ResolvedModule {
+    export function getResolvedModule(sourceFile: SourceFile, moduleNameText: string): ResolvedModuleFull {
         return hasResolvedModule(sourceFile, moduleNameText) ? sourceFile.resolvedModules[moduleNameText] : undefined;
     }
 
-    export function setResolvedModule(sourceFile: SourceFile, moduleNameText: string, resolvedModule: ResolvedModule): void {
+    export function setResolvedModule(sourceFile: SourceFile, moduleNameText: string, resolvedModule: ResolvedModuleFull): void {
         if (!sourceFile.resolvedModules) {
-            sourceFile.resolvedModules = createMap<ResolvedModule>();
+            sourceFile.resolvedModules = createMap<ResolvedModuleFull>();
         }
 
         sourceFile.resolvedModules[moduleNameText] = resolvedModule;
@@ -108,11 +108,7 @@ namespace ts {
     }
 
     /* @internal */
-    /**
-     * Considers two ResolvedModules equal if they have the same `resolvedFileName`.
-     * Thus `{ ts: foo, js: bar }` is equal to `{ ts: foo, js: baz }` because `ts` is preferred.
-     */
-    export function moduleResolutionIsEqualTo(oldResolution: ResolvedModule, newResolution: ResolvedModule): boolean {
+    export function moduleResolutionIsEqualTo(oldResolution: ResolvedModuleFull, newResolution: ResolvedModuleFull): boolean {
         return oldResolution.isExternalLibraryImport === newResolution.isExternalLibraryImport &&
             oldResolution.extension === newResolution.extension &&
             oldResolution.resolvedFileName === newResolution.resolvedFileName;
diff --git a/src/harness/unittests/moduleResolution.ts b/src/harness/unittests/moduleResolution.ts
index 0c1934bb01c24..104d9f9e394eb 100644
--- a/src/harness/unittests/moduleResolution.ts
+++ b/src/harness/unittests/moduleResolution.ts
@@ -1,7 +1,7 @@
 /// <reference path="..\harness.ts" />
 
 namespace ts {
-    export function checkResolvedModule(expected: ResolvedModule, actual: ResolvedModule): boolean {
+    export function checkResolvedModule(expected: ResolvedModuleFull, actual: ResolvedModuleFull): boolean {
         if (!expected === !actual) {
             if (expected) {
                 assert.isTrue(expected.resolvedFileName === actual.resolvedFileName, `'resolvedFileName': expected '${expected.resolvedFileName}' to be equal to '${actual.resolvedFileName}'`);
@@ -13,13 +13,13 @@ namespace ts {
         return false;
     }
 
-    export function checkResolvedModuleWithFailedLookupLocations(actual: ResolvedModuleWithFailedLookupLocations, expectedResolvedModule: ResolvedModule, expectedFailedLookupLocations: string[]): void {
+    export function checkResolvedModuleWithFailedLookupLocations(actual: ResolvedModuleWithFailedLookupLocations, expectedResolvedModule: ResolvedModuleFull, expectedFailedLookupLocations: string[]): void {
         assert.isTrue(actual.resolvedModule !== undefined, "module should be resolved");
         checkResolvedModule(actual.resolvedModule, expectedResolvedModule);
         assert.deepEqual(actual.failedLookupLocations, expectedFailedLookupLocations);
     }
 
-    export function createResolvedModule(resolvedFileName: string, isExternalLibraryImport = false): ResolvedModule {
+    export function createResolvedModule(resolvedFileName: string, isExternalLibraryImport = false): ResolvedModuleFull {
         return { resolvedFileName, extension: extensionFromPath(resolvedFileName), isExternalLibraryImport };
     }
 
diff --git a/src/server/lsHost.ts b/src/server/lsHost.ts
index 641f8dbabe742..628de71bb7a91 100644
--- a/src/server/lsHost.ts
+++ b/src/server/lsHost.ts
@@ -151,7 +151,7 @@ namespace ts.server {
                 m => m.resolvedTypeReferenceDirective, r => r.resolvedFileName,  /*logChanges*/ false);
         }
 
-        resolveModuleNames(moduleNames: string[], containingFile: string): ResolvedModule[] {
+        resolveModuleNames(moduleNames: string[], containingFile: string): ResolvedModuleFull[] {
             return this.resolveNamesWithLocalCache(moduleNames, containingFile, this.resolvedModuleNames, this.resolveModuleName,
                 m => m.resolvedModule, r => r.resolvedFileName, /*logChanges*/ true);
         }
diff --git a/src/services/services.ts b/src/services/services.ts
index 5669134d37e75..8c11c707e5d60 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -467,7 +467,7 @@ namespace ts {
         public languageVariant: LanguageVariant;
         public identifiers: Map<string>;
         public nameTable: Map<number>;
-        public resolvedModules: Map<ResolvedModule>;
+        public resolvedModules: Map<ResolvedModuleFull>;
         public resolvedTypeReferenceDirectiveNames: Map<ResolvedTypeReferenceDirective>;
         public imports: LiteralExpression[];
         public moduleAugmentations: LiteralExpression[];
diff --git a/src/services/shims.ts b/src/services/shims.ts
index a3b99f81158c9..b1fac14674c32 100644
--- a/src/services/shims.ts
+++ b/src/services/shims.ts
@@ -316,7 +316,7 @@ namespace ts {
         private loggingEnabled = false;
         private tracingEnabled = false;
 
-        public resolveModuleNames: (moduleName: string[], containingFile: string) => ResolvedModule[];
+        public resolveModuleNames: (moduleName: string[], containingFile: string) => ResolvedModuleFull[];
         public resolveTypeReferenceDirectives: (typeDirectiveNames: string[], containingFile: string) => ResolvedTypeReferenceDirective[];
         public directoryExists: (directoryName: string) => boolean;
 

From 4b50ef35859a1f1c1cf07e65439e12aa4c350596 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 27 Oct 2016 13:07:36 -0700
Subject: [PATCH 102/224] Consider index signatures in type produced by 'keyof
 T'

---
 src/compiler/checker.ts              | 97 +++++++++++++++-------------
 src/compiler/diagnosticMessages.json | 10 ++-
 src/compiler/types.ts                |  4 +-
 3 files changed, 62 insertions(+), 49 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 0d23fbb44a5ce..680147a5b6f92 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -136,6 +136,7 @@ namespace ts {
         const voidType = createIntrinsicType(TypeFlags.Void, "void");
         const neverType = createIntrinsicType(TypeFlags.Never, "never");
         const silentNeverType = createIntrinsicType(TypeFlags.Never, "never");
+        const stringOrNumberType = getUnionType([stringType, numberType]);
 
         const emptyObjectType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
         const emptyGenericType = <GenericType><ObjectType>createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
@@ -4473,22 +4474,13 @@ namespace ts {
          * type itself. Note that the apparent type of a union type is the union type itself.
          */
         function getApparentType(type: Type): Type {
-            if (type.flags & TypeFlags.TypeParameter) {
-                type = getApparentTypeOfTypeParameter(<TypeParameter>type);
-            }
-            if (type.flags & TypeFlags.StringLike) {
-                type = globalStringType;
-            }
-            else if (type.flags & TypeFlags.NumberLike) {
-                type = globalNumberType;
-            }
-            else if (type.flags & TypeFlags.BooleanLike) {
-                type = globalBooleanType;
-            }
-            else if (type.flags & TypeFlags.ESSymbol) {
-                type = getGlobalESSymbolType();
-            }
-            return type;
+            const t = type.flags & TypeFlags.TypeParameter ? getApparentTypeOfTypeParameter(<TypeParameter>type) : type;
+            return t.flags & TypeFlags.StringLike ? globalStringType :
+                t.flags & TypeFlags.NumberLike ? globalNumberType :
+                t.flags & TypeFlags.BooleanLike ? globalBooleanType :
+                t.flags & TypeFlags.ESSymbol ? getGlobalESSymbolType() :
+                t.flags & TypeFlags.Index ? stringOrNumberType :
+                t;
         }
 
         function createUnionOrIntersectionProperty(containingType: UnionOrIntersectionType, name: string): Symbol {
@@ -5674,10 +5666,6 @@ namespace ts {
             return links.resolvedType;
         }
 
-        function getLiteralTypeFromPropertyName(prop: Symbol) {
-            return startsWith(prop.name, "__@") ? neverType : getLiteralTypeForText(TypeFlags.StringLiteral, unescapeIdentifier(prop.name));
-        }
-
         function getIndexTypeForTypeParameter(type: TypeParameter) {
             if (!type.resolvedIndexType) {
                 type.resolvedIndexType = <IndexType>createType(TypeFlags.Index);
@@ -5686,10 +5674,19 @@ namespace ts {
             return type.resolvedIndexType;
         }
 
+        function getLiteralTypeFromPropertyName(prop: Symbol) {
+            return startsWith(prop.name, "__@") ? neverType : getLiteralTypeForText(TypeFlags.StringLiteral, unescapeIdentifier(prop.name));
+        }
+
+        function getLiteralTypeFromPropertyNames(type: Type) {
+            return getUnionType(map(getPropertiesOfType(type), getLiteralTypeFromPropertyName));
+        }
+
         function getIndexType(type: Type): Type {
-            return type.flags & TypeFlags.TypeParameter ?
-                getIndexTypeForTypeParameter(<TypeParameter>type) :
-                getUnionType(map(getPropertiesOfType(type), getLiteralTypeFromPropertyName));
+            return type.flags & TypeFlags.TypeParameter ? getIndexTypeForTypeParameter(<TypeParameter>type) :
+                getIndexInfoOfType(type, IndexKind.String) ? stringOrNumberType :
+                getIndexInfoOfType(type, IndexKind.Number) ? getUnionType([numberType, getLiteralTypeFromPropertyNames(type)]) :
+                getLiteralTypeFromPropertyNames(type);
         }
 
         function getTypeFromTypeOperatorNode(node: TypeOperatorNode) {
@@ -5712,33 +5709,45 @@ namespace ts {
             return indexedAccessTypes[objectType.id] || (indexedAccessTypes[objectType.id] = createIndexedAccessType(objectType, keyType));
         }
 
+        function getPropertyTypeForIndexType(objectType: Type, indexType: Type) {
+            return indexType.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral | TypeFlags.EnumLiteral) && getTypeOfPropertyOfType(objectType, escapeIdentifier((<LiteralType>indexType).text)) ||
+                isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.NumberLike) && getIndexTypeOfType(objectType, IndexKind.Number) ||
+                isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.StringLike | TypeFlags.NumberLike) && getIndexTypeOfType(objectType, IndexKind.String) ||
+                undefined;
+        }
+
         function getIndexedAccessType(objectType: Type, keyType: Type) {
-            if (keyType.flags & TypeFlags.TypeParameter) {
-                return getIndexedAccessTypeForTypeParameter(objectType, <TypeParameter>keyType);
-            }
-            if (isTypeOfKind(keyType, TypeFlags.StringLiteral) && !(keyType.flags & TypeFlags.Intersection)) {
-                return mapType(keyType, t => getTypeOfPropertyOfType(objectType, escapeIdentifier((<LiteralType>t).text)) || unknownType);
-            }
-            return keyType.flags & TypeFlags.Any ? anyType : unknownType;
+            return keyType.flags & TypeFlags.Any ? anyType :
+                keyType.flags & TypeFlags.TypeParameter ? getIndexedAccessTypeForTypeParameter(objectType, <TypeParameter>keyType) :
+                mapType(keyType, t => getPropertyTypeForIndexType(objectType, t) || unknownType);
         }
 
         function resolveIndexedAccessTypeNode(node: IndexedAccessTypeNode) {
             const objectType = getTypeFromTypeNodeNoAlias(node.objectType);
-            const keyType = getTypeFromTypeNodeNoAlias(node.indexType);
-            if (keyType.flags & TypeFlags.TypeParameter &&
-                getConstraintOfTypeParameter(<TypeParameter>keyType) === getIndexType(objectType)) {
-                return getIndexedAccessType(objectType, keyType);
-            }
-            if (isTypeOfKind(keyType, TypeFlags.StringLiteral) && !(keyType.flags & TypeFlags.Intersection)) {
-                const missing = forEachType(keyType, t => getTypeOfPropertyOfType(objectType, escapeIdentifier((<LiteralType>t).text)) ? undefined : (<LiteralType>t).text);
-                if (missing) {
-                    error(node.indexType, Diagnostics.Property_0_is_missing_in_type_1, missing, typeToString(objectType));
+            const indexType = getTypeFromTypeNodeNoAlias(node.indexType);
+            if (indexType.flags & TypeFlags.TypeParameter) {
+                if (!isTypeAssignableTo(getConstraintOfTypeParameter(<TypeParameter>indexType), getIndexType(objectType))) {
+                    error(node.indexType, Diagnostics.Type_0_is_not_constrained_to_keyof_1, typeToString(indexType), typeToString(objectType));
                     return unknownType;
                 }
-                return getIndexedAccessType(objectType, keyType);
+                return getIndexedAccessType(objectType, indexType);
             }
-            error(node.indexType, Diagnostics.Property_access_element_type_must_be_a_string_literal_type_or_a_type_parameter_constrained_to_keyof_0, typeToString(objectType));
-            return unknownType;
+            const indexTypes = indexType.flags & TypeFlags.Union && !(indexType.flags & TypeFlags.Primitive) ? (<UnionType>indexType).types : [indexType];
+            for (const t of indexTypes) {
+                if (!getPropertyTypeForIndexType(objectType, t)) {
+                    if (t.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) {
+                        error(node.indexType, Diagnostics.Property_0_does_not_exist_on_type_1, (<LiteralType>t).text, typeToString(objectType))
+                    }
+                    else if (t.flags & (TypeFlags.String | TypeFlags.Number)) {
+                        error(node.indexType, Diagnostics.Type_0_has_no_matching_index_signature_for_type_1, typeToString(objectType), typeToString(t));
+                    }
+                    else {
+                        error(node.indexType, Diagnostics.Type_0_cannot_be_used_as_an_index_type, typeToString(t));
+                    }
+                    return unknownType;
+                }
+            }
+            return getIndexedAccessType(objectType, indexType);
         }
 
         function getTypeFromIndexedAccessTypeNode(node: IndexedAccessTypeNode) {
@@ -8606,10 +8615,6 @@ namespace ts {
             return containsType(target.types, source);
         }
 
-        function forEachType<T>(type: Type, f: (t: Type) => T): T {
-            return type.flags & TypeFlags.Union ? forEach((<UnionType>type).types, f) : f(type);
-        }
-
         function filterType(type: Type, f: (t: Type) => boolean): Type {
             if (type.flags & TypeFlags.Union) {
                 const types = (<UnionType>type).types;
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 81882e0c3bba2..c08245eee91a6 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1751,10 +1751,18 @@
         "category": "Error",
         "code": 2535
     },
-    "Property access element type must be a string literal type or a type parameter constrained to 'keyof {0}'.": {
+    "Type '{0}' is not constrained to 'keyof {1}'.": {
         "category": "Error",
         "code": 2536
     },
+    "Type '{0}' has no matching index signature for type '{1}'.": {
+        "category": "Error",
+        "code": 2537
+    },
+    "Type '{0}' cannot be used as an index type.": {
+        "category": "Error",
+        "code": 2538
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 54aabcc6a81eb..2ea4dc71d886d 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2652,7 +2652,7 @@ namespace ts {
         Intrinsic = Any | String | Number | Boolean | BooleanLiteral | ESSymbol | Void | Undefined | Null | Never,
         /* @internal */
         Primitive = String | Number | Boolean | Enum | ESSymbol | Void | Undefined | Null | Literal,
-        StringLike = String | StringLiteral | Index,
+        StringLike = String | StringLiteral,
         NumberLike = Number | NumberLiteral | Enum | EnumLiteral,
         BooleanLike = Boolean | BooleanLiteral,
         EnumLike = Enum | EnumLiteral,
@@ -2662,7 +2662,7 @@ namespace ts {
 
         // 'Narrowable' types are types where narrowing actually narrows.
         // This *should* be every type other than null, undefined, void, and never
-        Narrowable = Any | StructuredType | TypeParameter | IndexedAccess | StringLike | NumberLike | BooleanLike | ESSymbol,
+        Narrowable = Any | StructuredType | TypeParameter | Index | IndexedAccess | StringLike | NumberLike | BooleanLike | ESSymbol,
         NotUnionOrUnit = Any | ESSymbol | Object,
         /* @internal */
         RequiresWidening = ContainsWideningType | ContainsObjectLiteral,

From bcc0807198ca89a80878e50bb9fd9258c6970d07 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 27 Oct 2016 13:14:56 -0700
Subject: [PATCH 103/224] Respond to PR comments

---
 scripts/processDiagnosticMessages.ts          |  2 +-
 src/compiler/binder.ts                        | 20 +++---
 src/compiler/checker.ts                       | 72 +++++++++----------
 src/compiler/collections.ts                   | 71 ++++++++++--------
 src/compiler/commandLineParser.ts             | 12 ++--
 src/compiler/core.ts                          |  2 +-
 src/compiler/declarationEmitter.ts            |  2 +-
 src/compiler/emitter.ts                       |  2 +-
 src/compiler/factory.ts                       |  6 +-
 src/compiler/parser.ts                        |  2 +-
 src/compiler/performance.ts                   |  6 +-
 src/compiler/program.ts                       | 14 ++--
 src/compiler/sys.ts                           |  4 +-
 src/compiler/transformer.ts                   |  2 +-
 src/compiler/transformers/es2015.ts           |  8 +--
 src/compiler/transformers/generators.ts       |  6 +-
 src/compiler/transformers/module/module.ts    |  8 +--
 src/compiler/transformers/module/system.ts    | 12 ++--
 src/compiler/transformers/ts.ts               |  6 +-
 src/compiler/tsc.ts                           |  6 +-
 src/compiler/types.ts                         |  4 +-
 src/compiler/utilities.ts                     | 14 ++--
 src/compiler/visitor.ts                       |  2 +-
 src/harness/fourslash.ts                      |  6 +-
 src/harness/harness.ts                        |  6 +-
 src/harness/loggedIO.ts                       |  2 +-
 .../unittests/cachingInServerLSHost.ts        |  2 +-
 src/harness/unittests/moduleResolution.ts     |  2 +-
 src/harness/unittests/session.ts              |  4 +-
 .../unittests/tsserverProjectSystem.ts        |  6 +-
 src/harness/unittests/typingsInstaller.ts     |  2 +-
 src/server/builder.ts                         |  2 +-
 src/server/client.ts                          |  2 +-
 src/server/editorServices.ts                  | 10 +--
 src/server/lsHost.ts                          |  2 +-
 src/server/project.ts                         |  4 +-
 src/server/typingsCache.ts                    |  4 +-
 .../typingsInstaller/typingsInstaller.ts      | 10 +--
 src/server/utilities.ts                       |  2 +-
 src/services/codefixes/codeFixProvider.ts     |  2 +-
 src/services/completions.ts                   | 10 +--
 src/services/documentHighlights.ts            |  2 +-
 src/services/documentRegistry.ts              |  2 +-
 src/services/findAllReferences.ts             |  6 +-
 src/services/jsTyping.ts                      |  4 +-
 src/services/navigationBar.ts                 | 12 ++--
 src/services/patternMatcher.ts                |  2 +-
 src/services/services.ts                      |  4 +-
 48 files changed, 203 insertions(+), 190 deletions(-)

diff --git a/scripts/processDiagnosticMessages.ts b/scripts/processDiagnosticMessages.ts
index d6133e6dab0a5..a7e2f24fdb885 100644
--- a/scripts/processDiagnosticMessages.ts
+++ b/scripts/processDiagnosticMessages.ts
@@ -69,7 +69,7 @@ function checkForUniqueCodes(messages: string[], diagnosticTable: InputDiagnosti
 }
 
 function buildUniqueNameMap(names: string[]): ts.Map<string, string> {
-    var nameMap = new ts.StringMap<string>();
+    var nameMap = ts.createMap<string, string>();
 
     var uniqueNames = NameGenerator.ensureUniqueness(names, /* isCaseSensitive */ false, /* isFixed */ undefined);
 
diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index e3c460ad2ad6f..9bf8d4846ce12 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -147,7 +147,7 @@ namespace ts {
             options = opts;
             languageVersion = getEmitScriptTarget(options);
             inStrictMode = bindInStrictMode(file, opts);
-            classifiableNames = new StringSet();
+            classifiableNames = createSet();
             symbolCount = 0;
             skipTransformFlagAggregation = isDeclarationFile(file);
 
@@ -207,11 +207,11 @@ namespace ts {
             symbol.declarations.push(node);
 
             if (symbolFlags & SymbolFlags.HasExports && !symbol.exports) {
-                symbol.exports = new StringMap<Symbol>();
+                symbol.exports = createMap<string, Symbol>();
             }
 
             if (symbolFlags & SymbolFlags.HasMembers && !symbol.members) {
-                symbol.members = new StringMap<Symbol>();
+                symbol.members = createMap<string, Symbol>();
             }
 
             if (symbolFlags & SymbolFlags.Value) {
@@ -484,7 +484,7 @@ namespace ts {
             if (containerFlags & ContainerFlags.IsContainer) {
                 container = blockScopeContainer = node;
                 if (containerFlags & ContainerFlags.HasLocals) {
-                    container.locals = new StringMap<Symbol>();
+                    container.locals = createMap<string, Symbol>();
                 }
                 addToContainerChain(container);
             }
@@ -1525,7 +1525,7 @@ namespace ts {
 
             const typeLiteralSymbol = createSymbol(SymbolFlags.TypeLiteral, "__type");
             addDeclarationToSymbol(typeLiteralSymbol, node, SymbolFlags.TypeLiteral);
-            typeLiteralSymbol.members = new StringMap([[symbol.name, symbol]]);
+            typeLiteralSymbol.members = createMap([[symbol.name, symbol]]);
         }
 
         function bindObjectLiteralExpression(node: ObjectLiteralExpression) {
@@ -1535,7 +1535,7 @@ namespace ts {
             }
 
             if (inStrictMode) {
-                const seen = new StringMap<ElementKind>();
+                const seen = createMap<string, ElementKind>();
 
                 for (const prop of node.properties) {
                     if (prop.name.kind !== SyntaxKind.Identifier) {
@@ -1591,7 +1591,7 @@ namespace ts {
                 // fall through.
                 default:
                     if (!blockScopeContainer.locals) {
-                        blockScopeContainer.locals = new StringMap<Symbol>();
+                        blockScopeContainer.locals = createMap<string, Symbol>();
                         addToContainerChain(blockScopeContainer);
                     }
                     declareSymbol(blockScopeContainer.locals, undefined, node, symbolFlags, symbolExcludes);
@@ -2071,7 +2071,7 @@ namespace ts {
                 }
             }
 
-            file.symbol.globalExports = file.symbol.globalExports || new StringMap<Symbol>();
+            file.symbol.globalExports = file.symbol.globalExports || createMap<string, Symbol>();
             declareSymbol(file.symbol.globalExports, file.symbol, node, SymbolFlags.Alias, SymbolFlags.AliasExcludes);
         }
 
@@ -2118,7 +2118,7 @@ namespace ts {
             Debug.assert(isInJavaScriptFile(node));
             // Declare a 'member' if the container is an ES5 class or ES6 constructor
             if (container.kind === SyntaxKind.FunctionDeclaration || container.kind === SyntaxKind.FunctionExpression) {
-                container.symbol.members = container.symbol.members || new StringMap<Symbol>();
+                container.symbol.members = container.symbol.members || createMap<string, Symbol>();
                 // It's acceptable for multiple 'this' assignments of the same identifier to occur
                 declareSymbol(container.symbol.members, container.symbol, node, SymbolFlags.Property, SymbolFlags.PropertyExcludes & ~SymbolFlags.Property);
             }
@@ -2157,7 +2157,7 @@ namespace ts {
 
             // Set up the members collection if it doesn't exist already
             if (!funcSymbol.members) {
-                funcSymbol.members = new StringMap<Symbol>();
+                funcSymbol.members = createMap<string, Symbol>();
             }
 
             // Declare the method/property
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index fbb155a1d5a6b..281190d325653 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -47,7 +47,7 @@ namespace ts {
         let symbolCount = 0;
 
         const emptyArray: any[] = [];
-        const emptySymbols = new StringMap<Symbol>();
+        const emptySymbols = createMap<string, Symbol>();
 
         const compilerOptions = host.getCompilerOptions();
         const languageVersion = compilerOptions.target || ScriptTarget.ES3;
@@ -111,10 +111,10 @@ namespace ts {
         };
 
         const tupleTypes: GenericType[] = [];
-        const unionTypes = new StringMap<UnionType>();
-        const intersectionTypes = new StringMap<IntersectionType>();
-        const stringLiteralTypes = new StringMap<LiteralType>();
-        const numericLiteralTypes = new StringMap<LiteralType>();
+        const unionTypes = createMap<string, UnionType>();
+        const intersectionTypes = createMap<string, IntersectionType>();
+        const stringLiteralTypes = createMap<string, LiteralType>();
+        const numericLiteralTypes = createMap<string, LiteralType>();
         const evolvingArrayTypes: EvolvingArrayType[] = [];
 
         const unknownSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Transient, "unknown");
@@ -139,7 +139,7 @@ namespace ts {
 
         const emptyObjectType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
         const emptyGenericType = <GenericType><ObjectType>createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
-        emptyGenericType.instantiations = new StringMap<TypeReference>();
+        emptyGenericType.instantiations = createMap<string, TypeReference>();
 
         const anyFunctionType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
         // The anyFunctionType contains the anyFunctionType by definition. The flag is further propagated
@@ -155,7 +155,7 @@ namespace ts {
 
         const enumNumberIndexInfo = createIndexInfo(stringType, /*isReadonly*/ true);
 
-        const globals = new StringMap<Symbol>();
+        const globals = createMap<string, Symbol>();
         /**
          * List of every ambient module with a "*" wildcard.
          * Unlike other ambient modules, these can't be stored in `globals` because symbol tables only deal with exact matches.
@@ -325,7 +325,7 @@ namespace ts {
 
         let jsxElementType: Type;
         /** Things we lazy load from the JSX namespace */
-        const jsxTypes = new StringMap<Type>();
+        const jsxTypes = createMap<string, Type>();
         const JsxNames = {
             JSX: "JSX",
             IntrinsicElements: "IntrinsicElements",
@@ -336,11 +336,11 @@ namespace ts {
             IntrinsicClassAttributes: "IntrinsicClassAttributes"
         };
 
-        const subtypeRelation = new StringMap<RelationComparisonResult>();
-        const assignableRelation = new StringMap<RelationComparisonResult>();
-        const comparableRelation = new StringMap<RelationComparisonResult>();
-        const identityRelation = new StringMap<RelationComparisonResult>();
-        const enumRelation = new StringMap<boolean>();
+        const subtypeRelation = createMap<string, RelationComparisonResult>();
+        const assignableRelation = createMap<string, RelationComparisonResult>();
+        const comparableRelation = createMap<string, RelationComparisonResult>();
+        const identityRelation = createMap<string, RelationComparisonResult>();
+        const enumRelation = createMap<string, boolean>();
 
         // This is for caching the result of getSymbolDisplayBuilder. Do not access directly.
         let _displayBuilder: SymbolDisplayBuilder;
@@ -354,7 +354,7 @@ namespace ts {
             ResolvedReturnType
         }
 
-        const builtinGlobals = new StringMap([[undefinedSymbol.name, undefinedSymbol]]);
+        const builtinGlobals = createMap([[undefinedSymbol.name, undefinedSymbol]]);
 
         initializeTypeChecker();
 
@@ -437,11 +437,11 @@ namespace ts {
                     target.declarations.push(node);
                 });
                 if (source.members) {
-                    if (!target.members) target.members = new StringMap<Symbol>();
+                    if (!target.members) target.members = createMap<string, Symbol>();
                     mergeSymbolTable(target.members, source.members);
                 }
                 if (source.exports) {
-                    if (!target.exports) target.exports = new StringMap<Symbol>();
+                    if (!target.exports) target.exports = createMap<string, Symbol>();
                     mergeSymbolTable(target.exports, source.exports);
                 }
                 recordMergedSymbol(target, source);
@@ -1418,7 +1418,7 @@ namespace ts {
                 // This provides a name to the module. See the test tests/cases/fourslash/untypedModuleImport.ts
                 const newSymbol = createSymbol(SymbolFlags.ValueModule, quotedName);
                 // Module symbols are expected to have 'exports', although since this is an untyped module it can be empty.
-                newSymbol.exports = new StringMap<Symbol>();
+                newSymbol.exports = createMap<string, Symbol>();
                 // Cache it so subsequent accesses will return the same module.
                 globals.set(quotedName, newSymbol);
                 return newSymbol;
@@ -1531,8 +1531,8 @@ namespace ts {
                 // All export * declarations are collected in an __export symbol by the binder
                 const exportStars = symbol.exports.get("__export");
                 if (exportStars) {
-                    const nestedSymbols = new StringMap<Symbol>();
-                    const lookupTable = new StringMap<ExportCollisionTracker>();
+                    const nestedSymbols = createMap<string, Symbol>();
+                    const lookupTable = createMap<string, ExportCollisionTracker>();
                     for (const node of exportStars.declarations) {
                         const resolvedModule = resolveExternalModuleName(node, (node as ExportDeclaration).moduleSpecifier);
                         const exportedSymbols = visit(resolvedModule);
@@ -3237,7 +3237,7 @@ namespace ts {
 
         // Return the type implied by an object binding pattern
         function getTypeFromObjectBindingPattern(pattern: ObjectBindingPattern, includePatternInType: boolean, reportErrors: boolean): Type {
-            const members = new StringMap<Symbol>();
+            const members = createMap<string, Symbol>();
             let hasComputedProperties = false;
             forEach(pattern.elements, e => {
                 const name = e.propertyName || <Identifier>e.name;
@@ -3842,7 +3842,7 @@ namespace ts {
                     type.typeParameters = concatenate(outerTypeParameters, localTypeParameters);
                     type.outerTypeParameters = outerTypeParameters;
                     type.localTypeParameters = localTypeParameters;
-                    (<GenericType>type).instantiations = new StringMap([[getTypeListId(type.typeParameters), <GenericType>type]]);
+                    (<GenericType>type).instantiations = createMap([[getTypeListId(type.typeParameters), <GenericType>type]]);
                     (<GenericType>type).target = <GenericType>type;
                     (<GenericType>type).typeArguments = type.typeParameters;
                     type.thisType = <TypeParameter>createType(TypeFlags.TypeParameter);
@@ -3884,7 +3884,7 @@ namespace ts {
                     if (typeParameters) {
                         // Initialize the instantiation cache for generic type aliases. The declared type corresponds to
                         // an instantiation of the type alias with the type parameters supplied as type arguments.
-                        links.instantiations = new StringMap([[getTypeListId(links.typeParameters), type]]);
+                        links.instantiations = createMap([[getTypeListId(links.typeParameters), type]]);
                     }
                 }
                 else {
@@ -4572,7 +4572,7 @@ namespace ts {
         // these partial properties when identifying discriminant properties, but otherwise they are filtered out
         // and do not appear to be present in the union type.
         function getUnionOrIntersectionProperty(type: UnionOrIntersectionType, name: string): Symbol {
-            const properties = type.resolvedProperties || (type.resolvedProperties = new StringMap<Symbol>());
+            const properties = type.resolvedProperties || (type.resolvedProperties = createMap<string, Symbol>());
             let property = properties.get(name);
             if (!property) {
                 property = createUnionOrIntersectionProperty(type, name);
@@ -5393,7 +5393,7 @@ namespace ts {
             type.typeParameters = typeParameters;
             type.outerTypeParameters = undefined;
             type.localTypeParameters = typeParameters;
-            type.instantiations = new StringMap([[getTypeListId(type.typeParameters), <GenericType>type]]);
+            type.instantiations = createMap([[getTypeListId(type.typeParameters), <GenericType>type]]);
             type.target = <GenericType>type;
             type.typeArguments = type.typeParameters;
             type.thisType = <TypeParameter>createType(TypeFlags.TypeParameter);
@@ -6906,7 +6906,7 @@ namespace ts {
                 }
                 sourceStack[depth] = source;
                 targetStack[depth] = target;
-                maybeStack[depth] = new StringMap([[id, RelationComparisonResult.Succeeded]]);
+                maybeStack[depth] = createMap([[id, RelationComparisonResult.Succeeded]]);
                 depth++;
                 const saveExpandingFlags = expandingFlags;
                 if (!(expandingFlags & 1) && isDeeplyNestedGeneric(source, sourceStack, depth)) expandingFlags |= 1;
@@ -7591,7 +7591,7 @@ namespace ts {
         }
 
         function transformTypeOfMembers(type: Type, f: (propertyType: Type) => Type) {
-            const members = new StringMap<Symbol>();
+            const members = createMap<string, Symbol>();
             for (const property of getPropertiesOfObjectType(type)) {
                 const original = getTypeOfSymbol(property);
                 const updated = f(original);
@@ -7814,7 +7814,7 @@ namespace ts {
             let targetStack: Type[];
             let depth = 0;
             let inferiority = 0;
-            const visited = new StringSet();
+            const visited = createSet();
             inferFromTypes(originalSource, originalTarget);
 
             function isInProcess(source: Type, target: Type) {
@@ -8894,7 +8894,7 @@ namespace ts {
                 // If we have previously computed the control flow type for the reference at
                 // this flow loop junction, return the cached type.
                 const id = getFlowNodeId(flow);
-                const cache = flowLoopCaches[id] || (flowLoopCaches[id] = new StringMap<Type>());
+                const cache = flowLoopCaches[id] || (flowLoopCaches[id] = createMap<string, Type>());
                 if (!key) {
                     key = getFlowCacheKey(reference);
                 }
@@ -10594,7 +10594,7 @@ namespace ts {
             // Grammar checking
             checkGrammarObjectLiteralExpression(node, inDestructuringPattern);
 
-            const propertiesTable = new StringMap<Symbol>();
+            const propertiesTable = createMap<string, Symbol>();
             const propertiesArray: Symbol[] = [];
             const contextualType = getApparentTypeOfContextualType(node);
             const contextualTypeHasPattern = contextualType && contextualType.pattern &&
@@ -11145,7 +11145,7 @@ namespace ts {
 
             const targetAttributesType = getJsxElementAttributesType(node);
 
-            const nameTable = new StringSet();
+            const nameTable = createSet();
             // Process this array in right-to-left order so we know which
             // attributes (mostly from spreads) are being overwritten and
             // thus should have their types ignored
@@ -14622,8 +14622,8 @@ namespace ts {
                 Property = Getter | Setter
             }
 
-            const instanceNames = new StringMap<Accessor>();
-            const staticNames = new StringMap<Accessor>();
+            const instanceNames = createMap<string, Accessor>();
+            const staticNames = createMap<string, Accessor>();
             for (const member of node.members) {
                 if (member.kind === SyntaxKind.Constructor) {
                     for (const param of (member as ConstructorDeclaration).parameters) {
@@ -14672,7 +14672,7 @@ namespace ts {
         }
 
         function checkObjectTypeForDuplicateDeclarations(node: TypeLiteralNode | InterfaceDeclaration) {
-            const names = new StringSet();
+            const names = createSet();
             for (const member of node.members) {
                 if (member.kind == SyntaxKind.PropertySignature) {
                     let memberName: string;
@@ -18490,7 +18490,7 @@ namespace ts {
         }
 
         function getSymbolsInScope(location: Node, meaning: SymbolFlags): Symbol[] {
-            const symbols = new StringMap<Symbol>();
+            const symbols = createMap<string, Symbol>();
             let memberFlags: ModifierFlags = ModifierFlags.None;
 
             if (isInsideWithStatementBody(location)) {
@@ -20315,7 +20315,7 @@ namespace ts {
         }
 
         function checkGrammarObjectLiteralExpression(node: ObjectLiteralExpression, inDestructuring: boolean) {
-            const seen = new StringMap<SymbolFlags>();
+            const seen = createMap<string, SymbolFlags>();
             const Property = 1;
             const GetAccessor = 2;
             const SetAccessor = 4;
@@ -20402,7 +20402,7 @@ namespace ts {
         }
 
         function checkGrammarJsxElement(node: JsxOpeningLikeElement) {
-            const seen = new StringSet();
+            const seen = createSet();
             for (const attr of node.attributes) {
                 if (attr.kind === SyntaxKind.JsxSpreadAttribute) {
                     continue;
diff --git a/src/compiler/collections.ts b/src/compiler/collections.ts
index 5aa4c010875d8..01f3da2b9d342 100644
--- a/src/compiler/collections.ts
+++ b/src/compiler/collections.ts
@@ -2,10 +2,11 @@
 /* @internal */
 namespace ts {
     // The global Map object. This may not be available, so we must test for it.
-    declare const Map: { new<K, V>(pairs?: [K, V][]): Map<K, V> } | undefined;
+    // Non-ES6 native maps don't support constructor arguments, so `createMap` must provide that functionality.
+    declare const Map: { new<K, V>(): Map<K, V> } | undefined;
     const usingNativeMaps = typeof Map !== "undefined";
     // tslint:disable-next-line:no-in-operator
-    const fullyFeaturedMaps = usingNativeMaps && "keys" in Map.prototype && "values" in Map.prototype && "entries" in Map.prototype;
+    const usingES6NativeMaps = usingNativeMaps && "keys" in Map.prototype && "values" in Map.prototype && "entries" in Map.prototype;
 
     /** Extra Map methods that may not be available, so we must provide fallbacks. */
     interface ES6Map<K, V> extends Map<K, V> {
@@ -32,20 +33,18 @@ namespace ts {
         However, `forEach` will iterate over strings because values are stringified before being put in the map.
         */
 
-        constructor(pairs?: [K, V][]) {
-            if (pairs) {
-                for (const [key, value] of pairs) {
-                    this.data[key as string] = value;
-                }
-            }
-        }
+        constructor() {}
 
         clear(): void {
             this.data = createDictionaryModeObject<V>();
         }
 
-        delete(key: K): void {
-            delete this.data[key as string];
+        delete(key: K): boolean {
+            const had = this.has(key);
+            if (had) {
+                delete this.data[key as string];
+            }
+            return had;
         }
 
         get(key: K): V {
@@ -68,14 +67,22 @@ namespace ts {
         }
     }
 
+    const MapCtr = usingNativeMaps ? Map : ShimMap;
     /**
      * In runtimes without Maps, this is implemented using an object.
      * `pairs` is an optional list of entries to add to the new map.
      */
-    export const StringMap: { new<T>(pairs?: [string, T][]): Map<string, T>; } = usingNativeMaps ? Map : ShimMap;
+    export function createMap<K extends string | number, V>(pairs?: [K, V][]): Map<K, V> {
+        const map = new MapCtr<K, V>();
+
+        if (pairs) {
+            for (const [key, value] of pairs) {
+                map.set(key, value);
+            }
+        }
 
-    /** This is generic over the key type because it is usually an enum. */
-    export const NumberMap: { new<K extends number, V>(pairs?: [K, V][]): Map<K, V> } = usingNativeMaps ? Map : ShimMap;
+        return map;
+    }
 
     const createObject = Object.create;
     function createDictionaryModeObject<T>(): MapLike<T> {
@@ -94,7 +101,7 @@ namespace ts {
      * Iterates over entries in the map, returning the first output of `getResult` that is not `undefined`.
      * Only works for strings because shims iterate with `for-in`.
      */
-    export const findInMap: <V, U>(map: Map<string, V>, getResult: (value: V, key: string) => U | undefined) => U | undefined = fullyFeaturedMaps
+    export const findInMap: <V, U>(map: Map<string, V>, getResult: (value: V, key: string) => U | undefined) => U | undefined = usingES6NativeMaps
         ? <V, U>(map: ES6Map<string, V>, f: (value: V, key: string) => U | undefined) => {
             const iter = map.entries();
             while (true) {
@@ -122,7 +129,7 @@ namespace ts {
      * Whether `predicate` is true for at least one entry in the map.
      * Only works for strings because shims iterate with `for-in`.
      */
-    export const someInMap: <V>(map: Map<string, V>, predicate: (value: V, key: string) => boolean) => boolean = fullyFeaturedMaps
+    export const someInMap: <V>(map: Map<string, V>, predicate: (value: V, key: string) => boolean) => boolean = usingES6NativeMaps
         ? <V>(map: ES6Map<string, V>, predicate: (value: V, key: string) => boolean) =>
             someInIterator(map.entries(), ([key, value]) => predicate(value, key))
         : <V>(map: Map<string, V>, predicate: (value: V, key: string) => boolean) => {
@@ -137,13 +144,13 @@ namespace ts {
      * Whether `predicate` is true for at least one key in the map.
      * Only works for strings because shims iterate with `for-in`.
      */
-    export const someKeyInMap: (map: Map<string, any>, predicate: (key: string) => boolean) => boolean = fullyFeaturedMaps
+    export const someKeyInMap: (map: Map<string, any>, predicate: (key: string) => boolean) => boolean = usingES6NativeMaps
         ? (map: ES6Map<string, any>, predicate: (key: string) => boolean) => someInIterator(map.keys(), predicate)
         : (map: Map<string, any>, predicate: (key: string) => boolean) =>
             someInMap(map, (_value, key) => predicate(key));
 
     /** Whether `predicate` is true for at least one value in the map. */
-    export const someValueInMap: <T>(map: Map<any, T>, predicate: (value: T) => boolean) => boolean = fullyFeaturedMaps
+    export const someValueInMap: <T>(map: Map<any, T>, predicate: (value: T) => boolean) => boolean = usingES6NativeMaps
         ? <T>(map: ES6Map<any, T>, predicate: (value: T) => boolean) =>
             someInIterator(map.values(), predicate)
         : someInMap;
@@ -165,7 +172,7 @@ namespace ts {
      * `for (const key of map.keys()) action(key);`
      * Only works for strings because shims iterate with `for-in`.
      */
-    export const forEachKeyInMap: (map: Map<string, any>, action: (key: string) => void) => void = fullyFeaturedMaps
+    export const forEachKeyInMap: (map: Map<string, any>, action: (key: string) => void) => void = usingES6NativeMaps
         ? (map: ES6Map<string, any>, action: (key: string) => void) => {
             const iter: Iterator<string> = map.keys();
             while (true) {
@@ -200,7 +207,7 @@ namespace ts {
 
     /** Create a map from a MapLike. This is useful for writing large maps as object literals. */
     export function mapOfMapLike<T>(object: MapLike<T>): Map<string, T> {
-        const map = new StringMap<T>();
+        const map = createMap<string, T>();
         // Copies keys/values from template. Note that for..in will not throw if
         // template is undefined, and instead will just exit the loop.
         for (const key in object) if (hasProperty(object, key)) {
@@ -222,8 +229,12 @@ namespace ts {
             this.data = createDictionaryModeObject<true>();
         }
 
-        delete(value: string) {
-            delete this.data[value];
+        delete(value: string): boolean {
+            const had = this.has(value);
+            if (had) {
+                delete this.data[value];
+            }
+            return had;
         }
 
         forEach(action: (value: string) => void) {
@@ -250,8 +261,10 @@ namespace ts {
     declare const Set: { new(): Set<string> } | undefined;
     const usingNativeSets = typeof Set !== "undefined";
 
-    /** In runtimes without Sets, this is implemented using an object. */
-    export const StringSet: { new(): Set<string> } = usingNativeSets ? Set : ShimStringSet;
+    const SetCtr = usingNativeSets ? Set : ShimStringSet;
+    export function createSet(): Set<string> {
+        return new SetCtr();
+    }
 
     /** False if there are any values in the set. */
     export const setIsEmpty: (set: Set<string>) => boolean = usingNativeSets
@@ -273,7 +286,7 @@ namespace ts {
 
     /** Create a new copy of a Map. */
     export function cloneMap<T>(map: Map<string, T>) {
-        const clone = new StringMap<T>();
+        const clone = createMap<string, T>();
         copyMapEntriesFromTo(map, clone);
         return clone;
     }
@@ -309,7 +322,7 @@ namespace ts {
 
     /** Return a new map with each key transformed by `getNewKey`. */
     export function transformKeys<T>(map: Map<string, T>, getNewKey: (key: string) => string): Map<string, T> {
-        const newMap = new StringMap<T>();
+        const newMap = createMap<string, T>();
         map.forEach((value, key) => {
             newMap.set(getNewKey(key), value);
         });
@@ -382,7 +395,7 @@ namespace ts {
     export function arrayToMap<T>(array: T[], makeKey: (value: T) => string): Map<string, T>;
     export function arrayToMap<T, U>(array: T[], makeKey: (value: T) => string, makeValue: (value: T) => U): Map<string, U>;
     export function arrayToMap<T, U>(array: T[], makeKey: (value: T) => string, makeValue?: (value: T) => U): Map<string, T | U> {
-        const result = new StringMap<T | U>();
+        const result = createMap<string, T | U>();
         for (const value of array) {
             result.set(makeKey(value), makeValue ? makeValue(value) : value);
         }
@@ -437,7 +450,7 @@ namespace ts {
      * Creates a sorted array of keys.
      * Sorts keys according to the iteration order they would have if they were in an object, instead of from a Map.
      * This is so that tests run consistently whether or not we have a Map shim in place.
-     * The difference between Map iteration order and V8 object insertion order is that V8 moves natrual-number-like keys to the front.
+     * The difference between Map iteration order and V8 object insertion order is that V8 moves natural-number-like keys to the front.
      */
     export function sortInV8ObjectInsertionOrder<T>(values: T[], toKey: (t: T) => string): T[] {
         const naturalNumberKeys: T[] = [];
@@ -458,7 +471,7 @@ namespace ts {
 
     /** Union of the `getSet` of each element in the array. */
     export function setAggregate<T>(array: T[], getSet: (t: T) => Set<string>): Set<string> {
-        const result = new StringSet();
+        const result = createSet();
         for (const value of array) {
             copySetValuesFromTo(getSet(value), result);
         }
diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 691d9f60c9418..87337cb1e2e5c 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -500,8 +500,8 @@ namespace ts {
             return optionNameMapCache;
         }
 
-        const optionNameMap = new StringMap<CommandLineOption>();
-        const shortOptionNames = new StringMap<string>();
+        const optionNameMap = createMap<string, CommandLineOption>();
+        const shortOptionNames = createMap<string, string>();
         forEach(optionDeclarations, option => {
             optionNameMap.set(option.name.toLowerCase(), option);
             if (option.shortName) {
@@ -741,7 +741,7 @@ namespace ts {
         }
 
         function serializeCompilerOptions(options: CompilerOptions): MapLike<CompilerOptionsValue> {
-            const result = new StringMap<CompilerOptionsValue>();
+            const result = createMap<string, CompilerOptionsValue>();
             const optionsNameMap = getOptionNameMap().optionNameMap;
 
             for (const name in options) {
@@ -1172,12 +1172,12 @@ namespace ts {
         // Literal file names (provided via the "files" array in tsconfig.json) are stored in a
         // file map with a possibly case insensitive key. We use this map later when when including
         // wildcard paths.
-        const literalFileMap = new StringMap<string>();
+        const literalFileMap = createMap<string, string>();
 
         // Wildcard paths (provided via the "includes" array in tsconfig.json) are stored in a
         // file map with a possibly case insensitive key. We use this map to store paths matched
         // via wildcard, and to handle extension priority.
-        const wildcardFileMap = new StringMap<string>();
+        const wildcardFileMap = createMap<string, string>();
 
         if (include) {
             include = validateSpecs(include, errors, /*allowTrailingRecursion*/ false);
@@ -1276,7 +1276,7 @@ namespace ts {
         //  /a/b/a?z    - Watch /a/b directly to catch any new file matching a?z
         const rawExcludeRegex = getRegularExpressionForWildcard(exclude, path, "exclude");
         const excludeRegex = rawExcludeRegex && new RegExp(rawExcludeRegex, useCaseSensitiveFileNames ? "" : "i");
-        const wildcardDirectories = new StringMap<WatchDirectoryFlags>();
+        const wildcardDirectories = createMap<string, WatchDirectoryFlags>();
         if (include !== undefined) {
             const recursiveKeys: string[] = [];
             for (const file of include) {
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 3784a3d0fc712..208b4d0931a82 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -23,7 +23,7 @@ namespace ts {
     export const collator: { compare(a: string, b: string): number } = typeof Intl === "object" && typeof Intl.Collator === "function" ? new Intl.Collator() : undefined;
 
     export function createFileMap<T>(keyMapper?: (key: string) => string): FileMap<T> {
-        const files = new StringMap<T>();
+        const files = createMap<string, T>();
         return {
             get,
             set,
diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index 63d5864b5b229..0c3b2abf3f04d 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -267,7 +267,7 @@ namespace ts {
             }
 
             if (!usedTypeDirectiveReferences) {
-                usedTypeDirectiveReferences = new StringSet();
+                usedTypeDirectiveReferences = createSet();
             }
             for (const directive of typeReferenceDirectives) {
                 if (!usedTypeDirectiveReferences.has(directive)) {
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index be9cb8914288f..d0568293eb7a5 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -292,7 +292,7 @@ const _super = (function (geti, seti) {
             sourceMap.initialize(jsFilePath, sourceMapFilePath, sourceFiles, isBundledEmit);
             nodeIdToGeneratedName = [];
             autoGeneratedIdToGeneratedName = [];
-            generatedNameSet = new StringSet();
+            generatedNameSet = createSet();
             isOwnFileEmit = !isBundledEmit;
 
             // Emit helpers from all the files
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index d121755013a77..13f1230896e84 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -1622,7 +1622,7 @@ namespace ts {
         // flag and setting a parent node.
         const react = createIdentifier(reactNamespace || "React");
         react.flags &= ~NodeFlags.Synthesized;
-        // Set the parent that is in parse tree 
+        // Set the parent that is in parse tree
         // this makes sure that parent chain is intact for checker to traverse complete scope tree
         react.parent = getParseTreeNode(parent);
         return react;
@@ -2806,7 +2806,7 @@ namespace ts {
     }
 
     function mergeTokenSourceMapRanges(sourceRanges: Map<SyntaxKind, TextRange>, destRanges: Map<SyntaxKind, TextRange>): Map<SyntaxKind, TextRange> {
-        if (!destRanges) destRanges = new NumberMap<SyntaxKind, TextRange>();
+        if (!destRanges) destRanges = createMap<SyntaxKind, TextRange>();
         copyMapEntriesFromTo(sourceRanges, destRanges);
         return destRanges;
     }
@@ -2899,7 +2899,7 @@ namespace ts {
      */
     export function setTokenSourceMapRange<T extends Node>(node: T, token: SyntaxKind, range: TextRange) {
         const emitNode = getOrCreateEmitNode(node);
-        const tokenSourceMapRanges = emitNode.tokenSourceMapRanges || (emitNode.tokenSourceMapRanges = new NumberMap<SyntaxKind, TextRange>());
+        const tokenSourceMapRanges = emitNode.tokenSourceMapRanges || (emitNode.tokenSourceMapRanges = createMap<SyntaxKind, TextRange>());
         tokenSourceMapRanges.set(token, range);
         return node;
     }
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 6eab34e622c7f..ea33473fe40a6 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -601,7 +601,7 @@ namespace ts {
 
             parseDiagnostics = [];
             parsingContext = 0;
-            identifiers = new StringMap<string>();
+            identifiers = createMap<string, string>();
             identifierCount = 0;
             nodeCount = 0;
 
diff --git a/src/compiler/performance.ts b/src/compiler/performance.ts
index 9ac9b755570c7..6cb73e4d058c7 100644
--- a/src/compiler/performance.ts
+++ b/src/compiler/performance.ts
@@ -79,9 +79,9 @@ namespace ts.performance {
 
     /** Enables (and resets) performance measurements for the compiler. */
     export function enable() {
-        counts = new StringMap<number>();
-        marks = new StringMap<number>();
-        measures = new StringMap<number>();
+        counts = createMap<string, number>();
+        marks = createMap<string, number>();
+        measures = createMap<string, number>();
         enabled = true;
         profilerStart = timestamp();
     }
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 5d19f2a908c3b..8a2b4d86671bf 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -82,7 +82,7 @@ namespace ts {
     }
 
     export function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost {
-        const existingDirectories = new StringSet();
+        const existingDirectories = createSet();
 
         function getCanonicalFileName(fileName: string): string {
             // if underlying system can distinguish between two files whose names differs only in cases then file name already in canonical form.
@@ -136,7 +136,7 @@ namespace ts {
 
         function writeFileIfUpdated(fileName: string, data: string, writeByteOrderMark: boolean): void {
             if (!outputFingerprints) {
-                outputFingerprints = new StringMap<OutputFingerprint>();
+                outputFingerprints = createMap<string, OutputFingerprint>();
             }
 
             const hash = sys.createHash(data);
@@ -279,7 +279,7 @@ namespace ts {
             return [];
         }
         const resolutions: T[] = [];
-        const cache = new StringMap<T>();
+        const cache = createMap<string, T>();
         for (const name of names) {
             const result = cache.has(name)
                 ? cache.get(name)
@@ -297,7 +297,7 @@ namespace ts {
         let noDiagnosticsTypeChecker: TypeChecker;
         let classifiableNames: Set<string>;
 
-        let resolvedTypeReferenceDirectives = new StringMap<ResolvedTypeReferenceDirective>();
+        let resolvedTypeReferenceDirectives = createMap<string, ResolvedTypeReferenceDirective>();
         let fileProcessingDiagnostics = createDiagnosticCollection();
 
         // The below settings are to track if a .js file should be add to the program if loaded via searching under node_modules.
@@ -312,10 +312,10 @@ namespace ts {
 
         // If a module has some of its imports skipped due to being at the depth limit under node_modules, then track
         // this, as it may be imported at a shallower depth later, and then it will need its skipped imports processed.
-        const modulesWithElidedImports = new StringMap<boolean>();
+        const modulesWithElidedImports = createMap<string, boolean>();
 
         // Track source files that are source files found by searching under node_modules, as these shouldn't be compiled.
-        const sourceFilesFoundSearchingNodeModules = new StringMap<boolean>();
+        const sourceFilesFoundSearchingNodeModules = createMap<string, boolean>();
 
         performance.mark("beforeProgram");
 
@@ -1290,7 +1290,7 @@ namespace ts {
         function processImportedModules(file: SourceFile) {
             collectExternalModuleReferences(file);
             if (file.imports.length || file.moduleAugmentations.length) {
-                file.resolvedModules = new StringMap<ResolvedModuleFull>();
+                file.resolvedModules = createMap<string, ResolvedModuleFull>();
                 const moduleNames = map(concatenate(file.imports, file.moduleAugmentations), getTextOfLiteral);
                 const resolutions = resolveModuleNamesWorker(moduleNames, getNormalizedAbsolutePath(file.fileName, currentDirectory));
                 Debug.assert(resolutions.length === moduleNames.length);
diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index a35692c48f8b3..5df1976f98e34 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -237,9 +237,9 @@ namespace ts {
             const useNonPollingWatchers = process.env["TSC_NONPOLLING_WATCHER"];
 
             function createWatchedFileSet() {
-                const dirWatchers = new StringMap<DirectoryWatcher>();
+                const dirWatchers = createMap<string, DirectoryWatcher>();
                 // One file can have multiple watchers
-                const fileWatcherCallbacks = new StringMap<FileWatcherCallback[]>();
+                const fileWatcherCallbacks = createMap<string, FileWatcherCallback[]>();
                 return { addFile, removeFile };
 
                 function reduceDirWatcherRefCountForFile(fileName: string) {
diff --git a/src/compiler/transformer.ts b/src/compiler/transformer.ts
index cb501bdb6e40b..4534564a854a4 100644
--- a/src/compiler/transformer.ts
+++ b/src/compiler/transformer.ts
@@ -12,7 +12,7 @@
 
 /* @internal */
 namespace ts {
-    const moduleTransformerMap = new NumberMap<ModuleKind, Transformer>([
+    const moduleTransformerMap = createMap<ModuleKind, Transformer>([
         [ModuleKind.ES2015, transformES2015Module],
         [ModuleKind.System, transformSystemModule],
         [ModuleKind.AMD, transformModule],
diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
index 54c61819d7d96..4e0b0749d3a97 100644
--- a/src/compiler/transformers/es2015.ts
+++ b/src/compiler/transformers/es2015.ts
@@ -279,7 +279,7 @@ namespace ts {
             else if (node.transformFlags & TransformFlags.ContainsES2015 || (isInConstructorWithCapturedSuper && !isExpression(node))) {
                 // we want to dive in this branch either if node has children with ES2015 specific syntax
                 // or we are inside constructor that captures result of the super call so all returns without expression should be
-                // rewritten. Note: we skip expressions since returns should never appear there 
+                // rewritten. Note: we skip expressions since returns should never appear there
                 return visitEachChild(node, visitor, context);
             }
             else {
@@ -1880,7 +1880,7 @@ namespace ts {
         function visitLabeledStatement(node: LabeledStatement): VisitResult<Statement> {
             if (convertedLoopState) {
                 if (!convertedLoopState.labels) {
-                    convertedLoopState.labels = new StringMap<string>();
+                    convertedLoopState.labels = createMap<string, string>();
                 }
                 convertedLoopState.labels.set(node.label.text, node.label.text);
             }
@@ -2497,13 +2497,13 @@ namespace ts {
         function setLabeledJump(state: ConvertedLoopState, isBreak: boolean, labelText: string, labelMarker: string): void {
             if (isBreak) {
                 if (!state.labeledNonLocalBreaks) {
-                    state.labeledNonLocalBreaks = new StringMap<string>();
+                    state.labeledNonLocalBreaks = createMap<string, string>();
                 }
                 state.labeledNonLocalBreaks.set(labelText, labelMarker);
             }
             else {
                 if (!state.labeledNonLocalContinues) {
-                    state.labeledNonLocalContinues = new StringMap<string>();
+                    state.labeledNonLocalContinues = createMap<string, string>();
                 }
                 state.labeledNonLocalContinues.set(labelText, labelMarker);
             }
diff --git a/src/compiler/transformers/generators.ts b/src/compiler/transformers/generators.ts
index 37629bfc6a042..74bc4ef4f0a56 100644
--- a/src/compiler/transformers/generators.ts
+++ b/src/compiler/transformers/generators.ts
@@ -217,7 +217,7 @@ namespace ts {
         Endfinally = 7,
     }
 
-    const instructionNames = new NumberMap<Instruction, string>([
+    const instructionNames = createMap<Instruction, string>([
         [Instruction.Return, "return"],
         [Instruction.Break, "break"],
         [Instruction.Yield, "yield"],
@@ -2078,8 +2078,8 @@ namespace ts {
             const name = declareLocal(text);
 
             if (!renamedCatchVariables) {
-                renamedCatchVariables = new StringSet();
-                renamedCatchVariableDeclarations = new NumberMap<number, Identifier>();
+                renamedCatchVariables = createSet();
+                renamedCatchVariableDeclarations = createMap<number, Identifier>();
                 context.enableSubstitution(SyntaxKind.Identifier);
             }
 
diff --git a/src/compiler/transformers/module/module.ts b/src/compiler/transformers/module/module.ts
index d26958bb90220..11a2a3dccad96 100644
--- a/src/compiler/transformers/module/module.ts
+++ b/src/compiler/transformers/module/module.ts
@@ -10,7 +10,7 @@ namespace ts {
             importAliasNames: ParameterDeclaration[];
         }
 
-        const transformModuleDelegates = new NumberMap<ModuleKind, (node: SourceFile) => SourceFile>([
+        const transformModuleDelegates = createMap<ModuleKind, (node: SourceFile) => SourceFile>([
             [ModuleKind.None, transformCommonJSModule],
             [ModuleKind.CommonJS, transformCommonJSModule],
             [ModuleKind.AMD, transformAMDModule],
@@ -40,8 +40,8 @@ namespace ts {
         context.enableSubstitution(SyntaxKind.ShorthandPropertyAssignment); // Substitutes shorthand property assignments for imported/exported symbols.
         context.enableEmitNotification(SyntaxKind.SourceFile); // Restore state when substituting nodes in a file.
 
-        const moduleInfoMap = new NumberMap<number, ExternalModuleInfo>(); // The ExternalModuleInfo for each file.
-        const deferredExports = new NumberMap<number, Statement[]>(); // Exports to defer until an EndOfDeclarationMarker is found.
+        const moduleInfoMap = createMap<number, ExternalModuleInfo>(); // The ExternalModuleInfo for each file.
+        const deferredExports = createMap<number, Statement[]>(); // Exports to defer until an EndOfDeclarationMarker is found.
 
         let currentSourceFile: SourceFile; // The current file.
         let currentModuleInfo: ExternalModuleInfo; // The ExternalModuleInfo for the current file.
@@ -1101,7 +1101,7 @@ namespace ts {
             if (node.kind === SyntaxKind.SourceFile) {
                 currentSourceFile = <SourceFile>node;
                 currentModuleInfo = moduleInfoMap.get(getOriginalNodeId(currentSourceFile));
-                noSubstitution = new NumberMap<number, boolean>();
+                noSubstitution = createMap<number, boolean>();
 
                 previousOnEmitNode(emitContext, node, emitCallback);
 
diff --git a/src/compiler/transformers/module/system.ts b/src/compiler/transformers/module/system.ts
index ca3db346a23ba..f3db63287b238 100644
--- a/src/compiler/transformers/module/system.ts
+++ b/src/compiler/transformers/module/system.ts
@@ -28,10 +28,10 @@ namespace ts {
         context.enableSubstitution(SyntaxKind.PostfixUnaryExpression); // Substitutes updates to exported symbols.
         context.enableEmitNotification(SyntaxKind.SourceFile); // Restore state when substituting nodes in a file.
 
-        const moduleInfoMap = new NumberMap<number, ExternalModuleInfo>(); // The ExternalModuleInfo for each file.
-        const deferredExports = new NumberMap<number, Statement[]>(); // Exports to defer until an EndOfDeclarationMarker is found.
-        const exportFunctionsMap = new NumberMap<number, Identifier>(); // The export function associated with a source file.
-        const noSubstitutionMap = new NumberMap<number, Map<number, boolean>>(); // Set of nodes for which substitution rules should be ignored for each file.
+        const moduleInfoMap = createMap<number, ExternalModuleInfo>(); // The ExternalModuleInfo for each file.
+        const deferredExports = createMap<number, Statement[]>(); // Exports to defer until an EndOfDeclarationMarker is found.
+        const exportFunctionsMap = createMap<number, Identifier>(); // The export function associated with a source file.
+        const noSubstitutionMap = createMap<number, Map<number, boolean>>(); // Set of nodes for which substitution rules should be ignored for each file.
 
         let currentSourceFile: SourceFile; // The current file.
         let moduleInfo: ExternalModuleInfo; // ExternalModuleInfo for the current file.
@@ -138,7 +138,7 @@ namespace ts {
          * @param externalImports The imports for the file.
          */
         function collectDependencyGroups(externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[]) {
-            const groupIndices = new StringMap<number>();
+            const groupIndices = createMap<string, number>();
             const dependencyGroups: DependencyGroup[] = [];
             for (let i = 0; i < externalImports.length; i++) {
                 const externalImport = externalImports[i];
@@ -1739,7 +1739,7 @@ namespace ts {
          * @param node The node which should not be substituted.
          */
         function preventSubstitution<T extends Node>(node: T): T {
-            if (noSubstitution === undefined) noSubstitution = new NumberMap<number, boolean>();
+            if (noSubstitution === undefined) noSubstitution = createMap<number, boolean>();
             noSubstitution.set(getNodeId(node), true);
             return node;
         }
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 6d22dc12bc7f7..3e9a9855f7e7a 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -2245,7 +2245,7 @@ namespace ts {
             const savedCurrentScope = currentScope;
             const savedCurrentScopeFirstDeclarationsOfName = currentScopeFirstDeclarationsOfName;
             currentScope = body;
-            currentScopeFirstDeclarationsOfName = new StringMap<Node>();
+            currentScopeFirstDeclarationsOfName = createMap<string, Node>();
             startLexicalEnvironment();
 
             const statements = visitNodes(body.statements, visitor, isStatement, start);
@@ -2630,7 +2630,7 @@ namespace ts {
             const name = node.symbol && node.symbol.name;
             if (name) {
                 if (!currentScopeFirstDeclarationsOfName) {
-                    currentScopeFirstDeclarationsOfName = new StringMap<Node>();
+                    currentScopeFirstDeclarationsOfName = createMap<string, Node>();
                 }
 
                 setIfNotSet(currentScopeFirstDeclarationsOfName, name, node);
@@ -3218,7 +3218,7 @@ namespace ts {
                 context.enableSubstitution(SyntaxKind.Identifier);
 
                 // Keep track of class aliases.
-                classAliases = new NumberMap<number, Identifier>();
+                classAliases = createMap<number, Identifier>();
             }
         }
 
diff --git a/src/compiler/tsc.ts b/src/compiler/tsc.ts
index 5286c24d1f6b9..28b3b9f3068b9 100644
--- a/src/compiler/tsc.ts
+++ b/src/compiler/tsc.ts
@@ -127,7 +127,7 @@ namespace ts {
     const gutterSeparator = " ";
     const resetEscapeSequence = "\u001b[0m";
     const ellipsis = "...";
-    const categoryFormatMap = new NumberMap<DiagnosticCategory, string>([
+    const categoryFormatMap = createMap<DiagnosticCategory, string>([
         [DiagnosticCategory.Warning, yellowForegroundEscapeSequence],
         [DiagnosticCategory.Error, redForegroundEscapeSequence],
         [DiagnosticCategory.Message, blueForegroundEscapeSequence],
@@ -425,7 +425,7 @@ namespace ts {
             }
 
             // reset the cache of existing files
-            cachedExistingFiles = new StringMap<boolean>();
+            cachedExistingFiles = createMap<string, boolean>();
 
             const compileResult = compile(rootFileNames, compilerOptions, compilerHost);
 
@@ -706,7 +706,7 @@ namespace ts {
         const usageColumn: string[] = []; // Things like "-d, --declaration" go in here.
         const descriptionColumn: string[] = [];
 
-        const optionsDescriptionMap = new StringMap<string[]>();  // Map between option.description and list of option.type if it is a kind
+        const optionsDescriptionMap = createMap<string, string[]>();  // Map between option.description and list of option.type if it is a kind
 
         for (let i = 0; i < optsList.length; i++) {
             const option = optsList[i];
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index a14586daf65f7..12f46751f6414 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -17,7 +17,7 @@ namespace ts {
      */
     export interface Map<K, V> {
         clear(): void;
-        delete(key: K): void;
+        delete(key: K): boolean;
         /**
          * Call `action` for each entry in the map.
          * Since we use a `for-in` loop for our shims, `key` may be a string.
@@ -38,7 +38,7 @@ namespace ts {
     export interface Set<T> {
         add(value: T): void;
         clear(): void;
-        delete(value: T): void;
+        delete(value: T): boolean;
         forEach(action: (value: T) => void): void;
         has(value: T): boolean;
     }
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index d6bb132c2afb4..bd77d5b2138f3 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -93,7 +93,7 @@ namespace ts {
 
     export function setResolvedModule(sourceFile: SourceFile, moduleNameText: string, resolvedModule: ResolvedModuleFull): void {
         if (!sourceFile.resolvedModules) {
-            sourceFile.resolvedModules = new StringMap<ResolvedModuleFull>();
+            sourceFile.resolvedModules = createMap<string, ResolvedModuleFull>();
         }
 
         sourceFile.resolvedModules.set(moduleNameText, resolvedModule);
@@ -101,7 +101,7 @@ namespace ts {
 
     export function setResolvedTypeReferenceDirective(sourceFile: SourceFile, typeReferenceDirectiveName: string, resolvedTypeReferenceDirective: ResolvedTypeReferenceDirective): void {
         if (!sourceFile.resolvedTypeReferenceDirectiveNames) {
-            sourceFile.resolvedTypeReferenceDirectiveNames = new StringMap<ResolvedTypeReferenceDirective>();
+            sourceFile.resolvedTypeReferenceDirectiveNames = createMap<string, ResolvedTypeReferenceDirective>();
         }
 
         sourceFile.resolvedTypeReferenceDirectiveNames.set(typeReferenceDirectiveName, resolvedTypeReferenceDirective);
@@ -2201,7 +2201,7 @@ namespace ts {
 
     export function createDiagnosticCollection(): DiagnosticCollection {
         let nonFileDiagnostics: Diagnostic[] = [];
-        const fileDiagnostics = new StringMap<Diagnostic[]>();
+        const fileDiagnostics = createMap<string, Diagnostic[]>();
 
         let diagnosticsModified = false;
         let modificationCount = 0;
@@ -3349,7 +3349,7 @@ namespace ts {
         return false;
     }
 
-    const syntaxKindCache = new NumberMap<SyntaxKind, string>();
+    const syntaxKindCache = createMap<SyntaxKind, string>();
 
     export function formatSyntaxKind(kind: SyntaxKind): string {
         const syntaxKindEnum = (<any>ts).SyntaxKind;
@@ -3507,9 +3507,9 @@ namespace ts {
 
     export function collectExternalModuleInfo(sourceFile: SourceFile, resolver: EmitResolver): ExternalModuleInfo {
         const externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[] = [];
-        const exportSpecifiers = new StringMap<ExportSpecifier[]>();
-        const exportedBindings = new NumberMap<number, Identifier[]>();
-        const uniqueExports = new StringMap<Identifier>();
+        const exportSpecifiers = createMap<string, ExportSpecifier[]>();
+        const exportedBindings = createMap<number, Identifier[]>();
+        const uniqueExports = createMap<string, Identifier>();
         let hasExportDefault = false;
         let exportEquals: ExportAssignment = undefined;
         let hasExportStarsToExportValues = false;
diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index fabd5079bfc96..fb1c572f08241 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -46,7 +46,7 @@ namespace ts {
      *       supplant the existing `forEachChild` implementation if performance is not
      *       significantly impacted.
      */
-    const nodeEdgeTraversalMap = new NumberMap<SyntaxKind, NodeTraversalPath>([
+    const nodeEdgeTraversalMap = createMap<SyntaxKind, NodeTraversalPath>([
         [SyntaxKind.QualifiedName, [
             { name: "left", test: isEntityName },
             { name: "right", test: isIdentifier }
diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index 3b64092f2eae4..88181d5edd27b 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -189,7 +189,7 @@ namespace FourSlash {
 
         public formatCodeSettings: ts.FormatCodeSettings;
 
-        private inputFiles = new ts.StringMap<string>();  // Map between inputFile's fileName and its content for easily looking up when resolving references
+        private inputFiles = ts.createMap<string, string>();  // Map between inputFile's fileName and its content for easily looking up when resolving references
 
         private static getDisplayPartsJson(displayParts: ts.SymbolDisplayPart[]) {
             let result = "";
@@ -674,7 +674,7 @@ namespace FourSlash {
 
         public noItemsWithSameNameButDifferentKind(): void {
             const completions = this.getCompletionListAtCaret();
-            const uniqueItems = new ts.StringMap<string>();
+            const uniqueItems = ts.createMap<string, string>();
             for (const item of completions.entries) {
                 if (!ts.setIfNotSet(uniqueItems, item.name, item.kind)) {
                     const uniqueItem = uniqueItems.get(item.name);
@@ -1777,7 +1777,7 @@ namespace FourSlash {
         }
 
         private rangesByTextMap(): ts.Map<string, Range[]> {
-            const result = new ts.StringMap<Range[]>();
+            const result = ts.createMap<string, Range[]>();
             for (const range of this.getRanges()) {
                 const text = this.rangeText(range);
                 ts.multiMapAdd(result, text, range);
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index 8cdaa326cea75..a029dfc38014d 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -922,7 +922,7 @@ namespace Harness {
         export const defaultLibFileName = "lib.d.ts";
         export const es2015DefaultLibFileName = "lib.es2015.d.ts";
 
-        const libFileNameSourceFileMap = new ts.StringMap<ts.SourceFile>([[
+        const libFileNameSourceFileMap = ts.createMap<string, ts.SourceFile>([[
             defaultLibFileName,
             createSourceFileAndAssertInvariants(defaultLibFileName, IO.readFile(libFolder + "lib.es5.d.ts"), /*languageVersion*/ ts.ScriptTarget.Latest)
         ]]);
@@ -1089,7 +1089,7 @@ namespace Harness {
         let optionsIndex: ts.Map<string, ts.CommandLineOption>;
         function getCommandLineOption(name: string): ts.CommandLineOption {
             if (!optionsIndex) {
-                optionsIndex = new ts.StringMap<ts.CommandLineOption>();
+                optionsIndex = ts.createMap<string, ts.CommandLineOption>();
                 const optionDeclarations = harnessOptionDeclarations.concat(ts.optionDeclarations);
                 for (const option of optionDeclarations) {
                     optionsIndex.set(option.name.toLowerCase(), option);
@@ -1452,7 +1452,7 @@ namespace Harness {
 
             const fullWalker = new TypeWriterWalker(program, /*fullTypeCheck*/ true);
 
-            const fullResults = new ts.StringMap<TypeWriterResult[]>();
+            const fullResults = ts.createMap<string, TypeWriterResult[]>();
 
             for (const sourceFile of allFiles) {
                 fullResults.set(sourceFile.unitName, fullWalker.getTypeAndSymbols(sourceFile.unitName));
diff --git a/src/harness/loggedIO.ts b/src/harness/loggedIO.ts
index 1b1c8130ba376..a4cd4d36b39da 100644
--- a/src/harness/loggedIO.ts
+++ b/src/harness/loggedIO.ts
@@ -91,7 +91,7 @@ namespace Playback {
     }
 
     function memoize<T>(func: (s: string) => T): Memoized<T> {
-        const lookup = new ts.StringMap<T>();
+        const lookup = ts.createMap<string, T>();
         const run: Memoized<T> = <Memoized<T>>((s: string) =>
             ts.getOrUpdateAndAllowUndefined(lookup, s, func));
         run.reset = () => {
diff --git a/src/harness/unittests/cachingInServerLSHost.ts b/src/harness/unittests/cachingInServerLSHost.ts
index ec009e118fbc1..1bfff0bf6a920 100644
--- a/src/harness/unittests/cachingInServerLSHost.ts
+++ b/src/harness/unittests/cachingInServerLSHost.ts
@@ -7,7 +7,7 @@ namespace ts {
     }
 
     function createDefaultServerHost(fileMap: Map<string, File>): server.ServerHost {
-        const existingDirectories = new StringSet();
+        const existingDirectories = createSet();
         forEachKeyInMap(fileMap, name => {
             let dir = getDirectoryPath(name);
             let previous: string;
diff --git a/src/harness/unittests/moduleResolution.ts b/src/harness/unittests/moduleResolution.ts
index d732f8ddabec4..5f07e46cbcfca 100644
--- a/src/harness/unittests/moduleResolution.ts
+++ b/src/harness/unittests/moduleResolution.ts
@@ -32,7 +32,7 @@ namespace ts {
         const map = arrayToMap(files, f => f.name);
 
         if (hasDirectoryExists) {
-            const directories = new StringSet();
+            const directories = createSet();
             for (const f of files) {
                 let name = getDirectoryPath(f.name);
                 while (true) {
diff --git a/src/harness/unittests/session.ts b/src/harness/unittests/session.ts
index 8d1b01ebfda2e..53f3ec3deb287 100644
--- a/src/harness/unittests/session.ts
+++ b/src/harness/unittests/session.ts
@@ -411,8 +411,8 @@ namespace ts.server {
         class InProcClient {
             private server: InProcSession;
             private seq = 0;
-            private callbacks = new NumberMap<number, (resp: protocol.Response) => void>();
-            private eventHandlers = new StringMap<(args: any) => void>();
+            private callbacks = createMap<number, (resp: protocol.Response) => void>();
+            private eventHandlers = createMap<string, (args: any) => void>();
 
             handle(msg: protocol.Message): void {
                 if (msg.type === "response") {
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index b18a21350e103..8972da33bb1eb 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -298,7 +298,7 @@ namespace ts.projectSystem {
     }
 
     export class Callbacks {
-        private map = new NumberMap<number, TimeOutCallback>();
+        private map = createMap<number, TimeOutCallback>();
         private nextId = 1;
 
         register(cb: (...args: any[]) => void, args: any[]) {
@@ -335,8 +335,8 @@ namespace ts.projectSystem {
         private timeoutCallbacks = new Callbacks();
         private immediateCallbacks = new Callbacks();
 
-        readonly watchedDirectories = new StringMap<{ cb: DirectoryWatcherCallback, recursive: boolean }[]>();
-        readonly watchedFiles = new StringMap<FileWatcherCallback[]>();
+        readonly watchedDirectories = createMap<string, { cb: DirectoryWatcherCallback, recursive: boolean }[]>();
+        readonly watchedFiles = createMap<string, FileWatcherCallback[]>();
 
 
         private filesOrFolders: FileOrFolder[];
diff --git a/src/harness/unittests/typingsInstaller.ts b/src/harness/unittests/typingsInstaller.ts
index 121de92a2ed76..e101b932ef9f3 100644
--- a/src/harness/unittests/typingsInstaller.ts
+++ b/src/harness/unittests/typingsInstaller.ts
@@ -955,7 +955,7 @@ namespace ts.projectSystem {
                 content: ""
             };
             const host = createServerHost([f]);
-            const cache = new StringMap<string>();
+            const cache = createMap<string, string>();
             for (const name of JsTyping.nodeCoreModuleList) {
                 const result = JsTyping.discoverTypings(host, [f.path], getDirectoryPath(<Path>f.path), /*safeListPath*/ undefined, cache, { enableAutoDiscovery: true }, [name, "somename"]);
                 assert.deepEqual(result.newTypingNames.sort(), ["node", "somename"]);
diff --git a/src/server/builder.ts b/src/server/builder.ts
index 915d2e01efeee..59948f32df6f5 100644
--- a/src/server/builder.ts
+++ b/src/server/builder.ts
@@ -346,7 +346,7 @@ namespace ts.server {
 
             // Use slice to clone the array to avoid manipulating in place
             const queue = fileInfo.referencedBy.slice(0);
-            const fileNameSet = new StringMap<ScriptInfo>();
+            const fileNameSet = createMap<string, ScriptInfo>();
             fileNameSet.set(scriptInfo.fileName, scriptInfo);
             while (queue.length > 0) {
                 const processingFileInfo = queue.pop();
diff --git a/src/server/client.ts b/src/server/client.ts
index 3989161c9611f..f4912025527e5 100644
--- a/src/server/client.ts
+++ b/src/server/client.ts
@@ -15,7 +15,7 @@ namespace ts.server {
 
     export class SessionClient implements LanguageService {
         private sequence: number = 0;
-        private lineMaps = new ts.StringMap<number[]>();
+        private lineMaps = ts.createMap<string, number[]>();
         private messages: string[] = [];
         private lastRenameEntry: RenameEntry;
 
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index 8ddd659aad393..109a372f8312a 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -18,7 +18,7 @@ namespace ts.server {
     }
 
     function prepareConvertersForEnumLikeCompilerOptions(commandLineOptions: CommandLineOption[]): Map<string, Map<string, number>> {
-        const map = new StringMap<Map<string, number>>();
+        const map = createMap<string, Map<string, number>>();
         for (const option of commandLineOptions) {
             if (typeof option.type === "object") {
                 const optionMap = <Map<string, number>>option.type;
@@ -159,12 +159,12 @@ namespace ts.server {
         /**
          * a path to directory watcher map that detects added tsconfig files
          **/
-        private readonly directoryWatchersForTsconfig = new StringMap<FileWatcher>();
+        private readonly directoryWatchersForTsconfig = createMap<string, FileWatcher>();
         /**
          * count of how many projects are using the directory watcher.
          * If the number becomes 0 for a watcher, then we should close it.
          **/
-        private readonly directoryWatchersRefCount = new StringMap<number>();
+        private readonly directoryWatchersRefCount = createMap<string, number>();
 
         constructor(private readonly projectService: ProjectService) {
         }
@@ -212,7 +212,7 @@ namespace ts.server {
         /**
          * maps external project file name to list of config files that were the part of this project
          */
-        private readonly externalProjectToConfiguredProjectMap = new StringMap<NormalizedPath[]>();
+        private readonly externalProjectToConfiguredProjectMap = createMap<string, NormalizedPath[]>();
 
         /**
          * external projects (configuration and list of root files is not controlled by tsserver)
@@ -902,7 +902,7 @@ namespace ts.server {
         private updateNonInferredProject<T>(project: ExternalProject | ConfiguredProject, newUncheckedFiles: T[], propertyReader: FilePropertyReader<T>, newOptions: CompilerOptions, newTypingOptions: TypingOptions, compileOnSave: boolean, configFileErrors: Diagnostic[]) {
             const oldRootScriptInfos = project.getRootScriptInfos();
             const newRootScriptInfos: ScriptInfo[] = [];
-            const newRootScriptInfoMap: Map<NormalizedPath, ScriptInfo> = new StringMap<ScriptInfo>();
+            const newRootScriptInfoMap: Map<NormalizedPath, ScriptInfo> = createMap<string, ScriptInfo>();
 
             let projectErrors: Diagnostic[];
             let rootFilesChanged = false;
diff --git a/src/server/lsHost.ts b/src/server/lsHost.ts
index b59a53e649d23..26da70c53899d 100644
--- a/src/server/lsHost.ts
+++ b/src/server/lsHost.ts
@@ -63,7 +63,7 @@ namespace ts.server {
             const path = toPath(containingFile, this.host.getCurrentDirectory(), this.getCanonicalFileName);
             const currentResolutionsInFile = cache.get(path);
 
-            const newResolutions = new StringMap<T>();
+            const newResolutions = createMap<string, T>();
             const resolvedModules: R[] = [];
             const compilerOptions = this.getCompilationSettings();
             const lastDeletedFileName = this.project.projectService.lastDeletedFile && this.project.projectService.lastDeletedFile.fileName;
diff --git a/src/server/project.ts b/src/server/project.ts
index 7181448bee19a..92431c08543b4 100644
--- a/src/server/project.ts
+++ b/src/server/project.ts
@@ -603,7 +603,7 @@ namespace ts.server {
             // We need to use a set here since the code can contain the same import twice,
             // but that will only be one dependency.
             // To avoid invernal conversion, the key of the referencedFiles map must be of type Path
-            const referencedFiles = new StringSet();
+            const referencedFiles = createSet();
             if (sourceFile.imports && sourceFile.imports.length > 0) {
                 const checker: TypeChecker = this.program.getTypeChecker();
                 for (const importName of sourceFile.imports) {
@@ -778,7 +778,7 @@ namespace ts.server {
             }
             const configDirectoryPath = getDirectoryPath(this.configFileName);
 
-            this.directoriesWatchedForWildcards = new StringMap<FileWatcher>();
+            this.directoriesWatchedForWildcards = createMap<string, FileWatcher>();
             this.wildcardDirectories.forEach((flag, directory) => {
                 if (comparePaths(configDirectoryPath, directory, ".", !this.projectService.host.useCaseSensitiveFileNames) !== Comparison.EqualTo) {
                     const recursive = (flag & WatchDirectoryFlags.Recursive) !== 0;
diff --git a/src/server/typingsCache.ts b/src/server/typingsCache.ts
index 577589c9c3677..399a0788c4744 100644
--- a/src/server/typingsCache.ts
+++ b/src/server/typingsCache.ts
@@ -31,7 +31,7 @@ namespace ts.server {
         if ((arr1 || emptyArray).length === 0 && (arr2 || emptyArray).length === 0) {
             return true;
         }
-        const set = new StringMap<boolean>();
+        const set = createMap<string, boolean>();
         let unique = 0;
 
         for (const v of arr1) {
@@ -72,7 +72,7 @@ namespace ts.server {
     }
 
     export class TypingsCache {
-        private readonly perProjectCache = new StringMap<TypingsCacheEntry>();
+        private readonly perProjectCache = createMap<string, TypingsCacheEntry>();
 
         constructor(private readonly installer: ITypingsInstaller) {
         }
diff --git a/src/server/typingsInstaller/typingsInstaller.ts b/src/server/typingsInstaller/typingsInstaller.ts
index dbebcd7567f8a..18c16b0d90ca5 100644
--- a/src/server/typingsInstaller/typingsInstaller.ts
+++ b/src/server/typingsInstaller/typingsInstaller.ts
@@ -78,10 +78,10 @@ namespace ts.server.typingsInstaller {
     };
 
     export abstract class TypingsInstaller {
-        private readonly packageNameToTypingLocation = new StringMap<string>();
-        private readonly missingTypingsSet = new StringSet();
-        private readonly knownCachesSet = new StringSet();
-        private readonly projectWatchers = new StringMap<FileWatcher[]>();
+        private readonly packageNameToTypingLocation = createMap<string, string>();
+        private readonly missingTypingsSet = createSet();
+        private readonly knownCachesSet = createSet();
+        private readonly projectWatchers = createMap<string, FileWatcher[]>();
         readonly pendingRunRequests: PendingRequest[] = [];
 
         private installRunCount = 1;
@@ -296,7 +296,7 @@ namespace ts.server.typingsInstaller {
                 if (this.log.isEnabled()) {
                     this.log.writeLine(`Requested to install typings ${JSON.stringify(typingsToInstall)}, installed typings ${JSON.stringify(installedTypings)}`);
                 }
-                const installedPackages = new StringSet();
+                const installedPackages = createSet();
                 const installedTypingFiles: string[] = [];
                 for (const t of installedTypings) {
                     const packageName = getBaseFileName(t);
diff --git a/src/server/utilities.ts b/src/server/utilities.ts
index 291058a973ec2..8cf2fbfe24218 100644
--- a/src/server/utilities.ts
+++ b/src/server/utilities.ts
@@ -225,7 +225,7 @@ namespace ts.server {
     }
 
     export class ThrottledOperations {
-        private pendingTimeouts = new StringMap<any>();
+        private pendingTimeouts = createMap<string, any>();
         constructor(private readonly host: ServerHost) {
         }
 
diff --git a/src/services/codefixes/codeFixProvider.ts b/src/services/codefixes/codeFixProvider.ts
index 6571f11f79ee9..6b27b11e4369f 100644
--- a/src/services/codefixes/codeFixProvider.ts
+++ b/src/services/codefixes/codeFixProvider.ts
@@ -14,7 +14,7 @@ namespace ts {
     }
 
     export namespace codefix {
-        const codeFixes = new NumberMap<number, CodeFix[]>();
+        const codeFixes = createMap<number, CodeFix[]>();
 
         export function registerCodeFix(action: CodeFix) {
             forEach(action.errorCodes, error => {
diff --git a/src/services/completions.ts b/src/services/completions.ts
index 4e7e27f771a5d..5005343ca9273 100644
--- a/src/services/completions.ts
+++ b/src/services/completions.ts
@@ -115,7 +115,7 @@ namespace ts.Completions {
 
         function getCompletionEntriesFromSymbols(symbols: Symbol[], entries: CompletionEntry[], location: Node, performCharacterChecks: boolean): Set<string> {
             const start = timestamp();
-            const uniqueNames = new StringSet();
+            const uniqueNames = createSet();
             if (symbols) {
                 for (const symbol of symbols) {
                     const entry = createCompletionEntry(symbol, location, performCharacterChecks);
@@ -363,7 +363,7 @@ namespace ts.Completions {
                      *
                      * both foo.ts and foo.tsx become foo
                      */
-                    const foundFiles = new StringSet();
+                    const foundFiles = createSet();
                     for (let filePath of files) {
                         filePath = normalizePath(filePath);
                         if (exclude && comparePaths(filePath, exclude, scriptPath, ignoreCase) === Comparison.EqualTo) {
@@ -1553,7 +1553,7 @@ namespace ts.Completions {
          *          do not occur at the current position and have not otherwise been typed.
          */
         function filterNamedImportOrExportCompletionItems(exportsOfModule: Symbol[], namedImportsOrExports: ImportOrExportSpecifier[]): Symbol[] {
-            const existingImportsOrExports = new StringSet();
+            const existingImportsOrExports = createSet();
 
             for (const element of namedImportsOrExports) {
                 // If this is the current item we are editing right now, do not filter it out
@@ -1583,7 +1583,7 @@ namespace ts.Completions {
                 return contextualMemberSymbols;
             }
 
-            const existingMemberNames = new StringSet();
+            const existingMemberNames = createSet();
             for (const m of existingMembers) {
                 // Ignore omitted expressions for missing members
                 if (m.kind !== SyntaxKind.PropertyAssignment &&
@@ -1628,7 +1628,7 @@ namespace ts.Completions {
          *          do not occur at the current position and have not otherwise been typed.
          */
         function filterJsxAttributes(symbols: Symbol[], attributes: NodeArray<JsxAttribute | JsxSpreadAttribute>): Symbol[] {
-            const seenNames = new StringSet();
+            const seenNames = createSet();
             for (const attr of attributes) {
                 // If this is the current item we are editing right now, do not filter it out
                 if (attr.getStart() <= position && position <= attr.getEnd()) {
diff --git a/src/services/documentHighlights.ts b/src/services/documentHighlights.ts
index d2c9ff5df7f34..791ad48d9d682 100644
--- a/src/services/documentHighlights.ts
+++ b/src/services/documentHighlights.ts
@@ -39,7 +39,7 @@ namespace ts.DocumentHighlights {
                     return undefined;
                 }
 
-                const fileNameToDocumentHighlights = new StringMap<DocumentHighlights>();
+                const fileNameToDocumentHighlights = createMap<string, DocumentHighlights>();
                 const result: DocumentHighlights[] = [];
                 for (const referencedSymbol of referencedSymbols) {
                     for (const referenceEntry of referencedSymbol.references) {
diff --git a/src/services/documentRegistry.ts b/src/services/documentRegistry.ts
index 7179daeae3a50..5c5a7797d2d09 100644
--- a/src/services/documentRegistry.ts
+++ b/src/services/documentRegistry.ts
@@ -105,7 +105,7 @@ namespace ts {
     export function createDocumentRegistry(useCaseSensitiveFileNames?: boolean, currentDirectory = ""): DocumentRegistry {
         // Maps from compiler setting target (ES3, ES5, etc.) to all the cached documents we have
         // for those settings.
-        const buckets = new StringMap<FileMap<DocumentRegistryEntry>>();
+        const buckets = createMap<string, FileMap<DocumentRegistryEntry>>();
         const getCanonicalFileName = createGetCanonicalFileName(!!useCaseSensitiveFileNames);
 
         function getKeyForCompilationSettings(settings: CompilerOptions): DocumentRegistryBucketKey {
diff --git a/src/services/findAllReferences.ts b/src/services/findAllReferences.ts
index 597eda404e282..fa86aba26aaa4 100644
--- a/src/services/findAllReferences.ts
+++ b/src/services/findAllReferences.ts
@@ -378,7 +378,7 @@ namespace ts.FindAllReferences {
             const possiblePositions = getPossibleSymbolReferencePositions(sourceFile, searchText, start, container.getEnd());
 
             const parents = getParentSymbolsOfPropertyAccess();
-            const inheritsFromCache = new StringMap<boolean>();
+            const inheritsFromCache = createMap<string, boolean>();
 
             if (possiblePositions.length) {
                 // Build the set of symbols to search for, initially it has only the current symbol
@@ -1047,7 +1047,7 @@ namespace ts.FindAllReferences {
 
                 // Add symbol of properties/methods of the same name in base classes and implemented interfaces definitions
                 if (!implementations && rootSymbol.parent && rootSymbol.parent.flags & (SymbolFlags.Class | SymbolFlags.Interface)) {
-                    getPropertySymbolsFromBaseTypes(rootSymbol.parent, rootSymbol.getName(), result, /*previousIterationSymbolsCache*/ new StringMap<Symbol>());
+                    getPropertySymbolsFromBaseTypes(rootSymbol.parent, rootSymbol.getName(), result, /*previousIterationSymbolsCache*/ createMap<string, Symbol>());
                 }
             });
 
@@ -1177,7 +1177,7 @@ namespace ts.FindAllReferences {
                     }
 
                     const result: Symbol[] = [];
-                    getPropertySymbolsFromBaseTypes(rootSymbol.parent, rootSymbol.getName(), result, /*previousIterationSymbolsCache*/ new StringMap<Symbol>());
+                    getPropertySymbolsFromBaseTypes(rootSymbol.parent, rootSymbol.getName(), result, /*previousIterationSymbolsCache*/ createMap<string, Symbol>());
                     return forEach(result, s => searchSymbols.indexOf(s) >= 0 ? s : undefined);
                 }
 
diff --git a/src/services/jsTyping.ts b/src/services/jsTyping.ts
index 5e021c3b058ed..a4841a17752b0 100644
--- a/src/services/jsTyping.ts
+++ b/src/services/jsTyping.ts
@@ -29,7 +29,7 @@ namespace ts.JsTyping {
     // that we are confident require typings
     let safeList: Map<string, string>;
 
-    const EmptySafeList = new StringMap<string>();
+    const EmptySafeList = createMap<string, string>();
 
     /* @internal */
     export const nodeCoreModuleList: ReadonlyArray<string> = [
@@ -62,7 +62,7 @@ namespace ts.JsTyping {
         { cachedTypingPaths: string[], newTypingNames: string[], filesToWatch: string[] } {
 
         // A typing name to typing file path mapping
-        const inferredTypings = new StringMap<string | undefined>();
+        const inferredTypings = createMap<string, string | undefined>();
 
         if (!typingOptions || !typingOptions.enableAutoDiscovery) {
             return { cachedTypingPaths: [], newTypingNames: [], filesToWatch: [] };
diff --git a/src/services/navigationBar.ts b/src/services/navigationBar.ts
index 26b9d3d979832..00472f46c74bb 100644
--- a/src/services/navigationBar.ts
+++ b/src/services/navigationBar.ts
@@ -239,7 +239,7 @@ namespace ts.NavigationBar {
 
     /** Merge declarations of the same kind. */
     function mergeChildren(children: NavigationBarNode[]): void {
-        const nameToItems = new StringMap<NavigationBarNode | NavigationBarNode[]>();
+        const nameToItems = createMap<string, NavigationBarNode | NavigationBarNode[]>();
         filterMutate(children, child => {
             const decl = <Declaration>child.node;
             const name = decl.name && nodeText(decl.name);
@@ -626,15 +626,15 @@ namespace ts.NavigationBar {
 
     /**
      * Matches all whitespace characters in a string. Eg:
-     * 
+     *
      * "app.
-     * 
+     *
      * onactivated"
-     * 
+     *
      * matches because of the newline, whereas
-     * 
+     *
      * "app.onactivated"
-     * 
+     *
      * does not match.
      */
     const whiteSpaceRegex = /\s+/g;
diff --git a/src/services/patternMatcher.ts b/src/services/patternMatcher.ts
index ec7a2bbfa124f..cf107d8984bf3 100644
--- a/src/services/patternMatcher.ts
+++ b/src/services/patternMatcher.ts
@@ -113,7 +113,7 @@ namespace ts {
         // we see the name of a module that is used everywhere, or the name of an overload).  As
         // such, we cache the information we compute about the candidate for the life of this
         // pattern matcher so we don't have to compute it multiple times.
-        const stringToWordSpans = new StringMap<TextSpan[]>();
+        const stringToWordSpans = createMap<string, TextSpan[]>();
 
         pattern = pattern.trim();
 
diff --git a/src/services/services.ts b/src/services/services.ts
index 5cde409a01123..ac77391cc1211 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -502,7 +502,7 @@ namespace ts {
         }
 
         private computeNamedDeclarations(): Map<string, Declaration[]> {
-            const result = new StringMap<Declaration[]>();
+            const result = createMap<string, Declaration[]>();
 
             forEachChild(this, visit);
 
@@ -1931,7 +1931,7 @@ namespace ts {
     }
 
     function initializeNameTable(sourceFile: SourceFile): void {
-        const nameTable = new StringMap<number>();
+        const nameTable = createMap<string, number>();
 
         walk(sourceFile);
         sourceFile.nameTable = nameTable;

From ece1f19099fb079390177ae9f8c70d5c49045cef Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 27 Oct 2016 13:54:26 -0700
Subject: [PATCH 104/224] Refactor getIndexedAccessType to be reusable from
 checkIndexedAccess

---
 src/compiler/checker.ts | 87 ++++++++++++++++++++++++-----------------
 1 file changed, 52 insertions(+), 35 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 680147a5b6f92..40e5a890f2ec6 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5697,63 +5697,80 @@ namespace ts {
             return links.resolvedType;
         }
 
-        function createIndexedAccessType(objectType: Type, keyType: TypeParameter) {
+        function createIndexedAccessType(objectType: Type, indexType: TypeParameter) {
             const type = <IndexedAccessType>createType(TypeFlags.IndexedAccess);
             type.objectType = objectType;
-            type.indexType = keyType;
+            type.indexType = indexType;
             return type;
         }
 
-        function getIndexedAccessTypeForTypeParameter(objectType: Type, keyType: TypeParameter) {
-            const indexedAccessTypes = keyType.resolvedIndexedAccessTypes || (keyType.resolvedIndexedAccessTypes = []);
-            return indexedAccessTypes[objectType.id] || (indexedAccessTypes[objectType.id] = createIndexedAccessType(objectType, keyType));
+        function getIndexedAccessTypeForTypeParameter(objectType: Type, indexType: TypeParameter) {
+            const indexedAccessTypes = indexType.resolvedIndexedAccessTypes || (indexType.resolvedIndexedAccessTypes = []);
+            return indexedAccessTypes[objectType.id] || (indexedAccessTypes[objectType.id] = createIndexedAccessType(objectType, indexType));
         }
 
-        function getPropertyTypeForIndexType(objectType: Type, indexType: Type) {
-            return indexType.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral | TypeFlags.EnumLiteral) && getTypeOfPropertyOfType(objectType, escapeIdentifier((<LiteralType>indexType).text)) ||
-                isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.NumberLike) && getIndexTypeOfType(objectType, IndexKind.Number) ||
-                isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.StringLike | TypeFlags.NumberLike) && getIndexTypeOfType(objectType, IndexKind.String) ||
-                undefined;
-        }
-
-        function getIndexedAccessType(objectType: Type, keyType: Type) {
-            return keyType.flags & TypeFlags.Any ? anyType :
-                keyType.flags & TypeFlags.TypeParameter ? getIndexedAccessTypeForTypeParameter(objectType, <TypeParameter>keyType) :
-                mapType(keyType, t => getPropertyTypeForIndexType(objectType, t) || unknownType);
+        function getPropertyTypeForIndexType(objectType: Type, indexType: Type, errorNode?: Node) {
+            if (indexType.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral | TypeFlags.EnumLiteral)) {
+                const propType = getTypeOfPropertyOfType(objectType, escapeIdentifier((<LiteralType>indexType).text));
+                if (propType) {
+                    return propType;
+                }
+            }
+            if (isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.NumberLike)) {
+                const numberIndexType = getIndexTypeOfType(objectType, IndexKind.Number);
+                if (numberIndexType) {
+                    return numberIndexType;
+                }
+            }
+            if (isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.StringLike | TypeFlags.NumberLike)) {
+                const stringIndexType = getIndexTypeOfType(objectType, IndexKind.String);
+                if (stringIndexType) {
+                    return stringIndexType;
+                }
+            }
+            if (errorNode) {
+                if (indexType.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) {
+                    error(errorNode, Diagnostics.Property_0_does_not_exist_on_type_1, (<LiteralType>indexType).text, typeToString(objectType));
+                }
+                else if (indexType.flags & (TypeFlags.String | TypeFlags.Number)) {
+                    error(errorNode, Diagnostics.Type_0_has_no_matching_index_signature_for_type_1, typeToString(objectType), typeToString(indexType));
+                }
+                else {
+                    error(errorNode, Diagnostics.Type_0_cannot_be_used_as_an_index_type, typeToString(indexType));
+                }
+            }
+            return unknownType;
         }
 
-        function resolveIndexedAccessTypeNode(node: IndexedAccessTypeNode) {
-            const objectType = getTypeFromTypeNodeNoAlias(node.objectType);
-            const indexType = getTypeFromTypeNodeNoAlias(node.indexType);
+        function getIndexedAccessType(objectType: Type, indexType: Type, errorNode?: Node) {
             if (indexType.flags & TypeFlags.TypeParameter) {
                 if (!isTypeAssignableTo(getConstraintOfTypeParameter(<TypeParameter>indexType), getIndexType(objectType))) {
-                    error(node.indexType, Diagnostics.Type_0_is_not_constrained_to_keyof_1, typeToString(indexType), typeToString(objectType));
+                    if (errorNode) {
+                        error(errorNode, Diagnostics.Type_0_is_not_constrained_to_keyof_1, typeToString(indexType), typeToString(objectType));
+                    }
                     return unknownType;
                 }
-                return getIndexedAccessType(objectType, indexType);
+                return getIndexedAccessTypeForTypeParameter(objectType, <TypeParameter>indexType);
             }
-            const indexTypes = indexType.flags & TypeFlags.Union && !(indexType.flags & TypeFlags.Primitive) ? (<UnionType>indexType).types : [indexType];
-            for (const t of indexTypes) {
-                if (!getPropertyTypeForIndexType(objectType, t)) {
-                    if (t.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) {
-                        error(node.indexType, Diagnostics.Property_0_does_not_exist_on_type_1, (<LiteralType>t).text, typeToString(objectType))
-                    }
-                    else if (t.flags & (TypeFlags.String | TypeFlags.Number)) {
-                        error(node.indexType, Diagnostics.Type_0_has_no_matching_index_signature_for_type_1, typeToString(objectType), typeToString(t));
-                    }
-                    else {
-                        error(node.indexType, Diagnostics.Type_0_cannot_be_used_as_an_index_type, typeToString(t));
+            if (indexType.flags & TypeFlags.Union && !(indexType.flags & TypeFlags.Primitive)) {
+                const propTypes: Type[] = [];
+                for (const t of (<UnionType>indexType).types) {
+                    const propType = getPropertyTypeForIndexType(objectType, t, errorNode);
+                    if (propType === unknownType) {
+                        return unknownType;
                     }
-                    return unknownType;
+                    propTypes.push(propType);
                 }
+                return getUnionType(propTypes);
             }
-            return getIndexedAccessType(objectType, indexType);
+            return getPropertyTypeForIndexType(objectType, indexType, errorNode);
         }
 
         function getTypeFromIndexedAccessTypeNode(node: IndexedAccessTypeNode) {
             const links = getNodeLinks(node);
             if (!links.resolvedType) {
-                links.resolvedType = resolveIndexedAccessTypeNode(node);
+                links.resolvedType = getIndexedAccessType(getTypeFromTypeNodeNoAlias(node.objectType),
+                    getTypeFromTypeNodeNoAlias(node.indexType), node.indexType);
             }
             return links.resolvedType;
         }

From 83fdecf86a77f5ed5470e91029b0730dcdfaed83 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 27 Oct 2016 14:41:40 -0700
Subject: [PATCH 105/224] Skip overloads with too-short function parameters

If the parameter of an overload is a function and the argument is also a
function, skip the overload if the parameter has fewer arguments than
the argument does. That overload cannot possibly apply, and should not
participate in, for example, contextual typing.

Example:

```ts
interface I {
  (a: number): void;
  (b: string, c): void;
}
declare function f(i: I): void;
f((x, y) => {});
```

This code now skips the first overload instead of considering.

This was a longstanding bug but was only uncovered now that more
functions expressions are context sensitive.
---
 src/compiler/checker.ts | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 4aee170f195d4..7cf61a7131786 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -11890,6 +11890,11 @@ namespace ts {
                     // If the effective argument type is 'undefined', there is no synthetic type
                     // for the argument. In that case, we should check the argument.
                     if (argType === undefined) {
+                        // If the parameter and argument are both functions and the parameter has fewer arguments than the argument,
+                        // then this signature is not applicable. Exit early.
+                        if (!reportErrors && isAritySmaller(paramType, arg)) {
+                            return false;
+                        }
                         argType = checkExpressionWithContextualType(arg, paramType, excludeArgument && excludeArgument[i] ? identityMapper : undefined);
                     }
 
@@ -11904,6 +11909,21 @@ namespace ts {
             return true;
         }
 
+        function isAritySmaller(sourceType: Type, target: Expression) {
+            if (isFunctionExpressionOrArrowFunction(target) && isFunctionType(sourceType)) {
+                let targetParameterCount = 0;
+                for (; targetParameterCount < target.parameters.length; targetParameterCount++) {
+                    const param = target.parameters[targetParameterCount];
+                    if (param.initializer || param.questionToken || param.dotDotDotToken || isJSDocOptionalParameter(param)) {
+                        break;
+                    }
+                }
+                const sourceSignatures = getSignaturesOfType(sourceType, SignatureKind.Call);
+                const sourceLengths = sourceSignatures.map(sig => !sig.hasRestParameter ? sig.parameters.length : Number.MAX_VALUE);
+                return forEach(sourceLengths, len => len < targetParameterCount);
+            }
+        }
+
         /**
          * Returns the this argument in calls like x.f(...) and x[f](...). Undefined otherwise.
          */

From cff586d4adaf4b776904f1cb645c8101034c7fbb Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 27 Oct 2016 14:44:54 -0700
Subject: [PATCH 106/224] Test skip overloads w/too-short function params

1. Update changed baseline.
2. Add a new test with baseline.
---
 .../contextualTypingOfTooShortOverloads.js    |  59 ++++++++
 ...ontextualTypingOfTooShortOverloads.symbols | 139 +++++++++++++++++
 .../contextualTypingOfTooShortOverloads.types | 143 ++++++++++++++++++
 ...AnnotatedFunctionInferenceError.errors.txt |   8 +-
 .../contextualTypingOfTooShortOverloads.ts    |  49 ++++++
 5 files changed, 394 insertions(+), 4 deletions(-)
 create mode 100644 tests/baselines/reference/contextualTypingOfTooShortOverloads.js
 create mode 100644 tests/baselines/reference/contextualTypingOfTooShortOverloads.symbols
 create mode 100644 tests/baselines/reference/contextualTypingOfTooShortOverloads.types
 create mode 100644 tests/cases/compiler/contextualTypingOfTooShortOverloads.ts

diff --git a/tests/baselines/reference/contextualTypingOfTooShortOverloads.js b/tests/baselines/reference/contextualTypingOfTooShortOverloads.js
new file mode 100644
index 0000000000000..55f1361f5a857
--- /dev/null
+++ b/tests/baselines/reference/contextualTypingOfTooShortOverloads.js
@@ -0,0 +1,59 @@
+//// [contextualTypingOfTooShortOverloads.ts]
+// small repro from #11875
+var use: Overload;
+use((req, res) => {});
+
+interface Overload {
+    (handler1: (req1: string) => void): void;
+    (handler2: (req2: number, res2: number) => void): void;
+}
+// larger repro from #11875
+let app: MyApp;
+app.use((err: any, req, res, next) => { return; });
+
+
+interface MyApp {
+    use: IRouterHandler<this> & IRouterMatcher<this>;
+}
+
+interface IRouterHandler<T> {
+    (...handlers: RequestHandler[]): T;
+    (...handlers: RequestHandlerParams[]): T;
+}
+
+interface IRouterMatcher<T> {
+    (path: PathParams, ...handlers: RequestHandler[]): T;
+    (path: PathParams, ...handlers: RequestHandlerParams[]): T;
+}
+
+type PathParams = string | RegExp | (string | RegExp)[];
+type RequestHandlerParams = RequestHandler | ErrorRequestHandler | (RequestHandler | ErrorRequestHandler)[];
+
+interface RequestHandler {
+    (req: Request, res: Response, next: NextFunction): any;
+}
+
+interface ErrorRequestHandler {
+    (err: any, req: Request, res: Response, next: NextFunction): any;
+}
+
+interface Request {
+    method: string;
+}
+
+interface Response {
+    statusCode: number;
+}
+
+interface NextFunction {
+    (err?: any): void;
+}
+
+
+//// [contextualTypingOfTooShortOverloads.js]
+// small repro from #11875
+var use;
+use(function (req, res) { });
+// larger repro from #11875
+var app;
+app.use(function (err, req, res, next) { return; });
diff --git a/tests/baselines/reference/contextualTypingOfTooShortOverloads.symbols b/tests/baselines/reference/contextualTypingOfTooShortOverloads.symbols
new file mode 100644
index 0000000000000..8f196cf48252d
--- /dev/null
+++ b/tests/baselines/reference/contextualTypingOfTooShortOverloads.symbols
@@ -0,0 +1,139 @@
+=== tests/cases/compiler/contextualTypingOfTooShortOverloads.ts ===
+// small repro from #11875
+var use: Overload;
+>use : Symbol(use, Decl(contextualTypingOfTooShortOverloads.ts, 1, 3))
+>Overload : Symbol(Overload, Decl(contextualTypingOfTooShortOverloads.ts, 2, 22))
+
+use((req, res) => {});
+>use : Symbol(use, Decl(contextualTypingOfTooShortOverloads.ts, 1, 3))
+>req : Symbol(req, Decl(contextualTypingOfTooShortOverloads.ts, 2, 5))
+>res : Symbol(res, Decl(contextualTypingOfTooShortOverloads.ts, 2, 9))
+
+interface Overload {
+>Overload : Symbol(Overload, Decl(contextualTypingOfTooShortOverloads.ts, 2, 22))
+
+    (handler1: (req1: string) => void): void;
+>handler1 : Symbol(handler1, Decl(contextualTypingOfTooShortOverloads.ts, 5, 5))
+>req1 : Symbol(req1, Decl(contextualTypingOfTooShortOverloads.ts, 5, 16))
+
+    (handler2: (req2: number, res2: number) => void): void;
+>handler2 : Symbol(handler2, Decl(contextualTypingOfTooShortOverloads.ts, 6, 5))
+>req2 : Symbol(req2, Decl(contextualTypingOfTooShortOverloads.ts, 6, 16))
+>res2 : Symbol(res2, Decl(contextualTypingOfTooShortOverloads.ts, 6, 29))
+}
+// larger repro from #11875
+let app: MyApp;
+>app : Symbol(app, Decl(contextualTypingOfTooShortOverloads.ts, 9, 3))
+>MyApp : Symbol(MyApp, Decl(contextualTypingOfTooShortOverloads.ts, 10, 51))
+
+app.use((err: any, req, res, next) => { return; });
+>app.use : Symbol(MyApp.use, Decl(contextualTypingOfTooShortOverloads.ts, 13, 17))
+>app : Symbol(app, Decl(contextualTypingOfTooShortOverloads.ts, 9, 3))
+>use : Symbol(MyApp.use, Decl(contextualTypingOfTooShortOverloads.ts, 13, 17))
+>err : Symbol(err, Decl(contextualTypingOfTooShortOverloads.ts, 10, 9))
+>req : Symbol(req, Decl(contextualTypingOfTooShortOverloads.ts, 10, 18))
+>res : Symbol(res, Decl(contextualTypingOfTooShortOverloads.ts, 10, 23))
+>next : Symbol(next, Decl(contextualTypingOfTooShortOverloads.ts, 10, 28))
+
+
+interface MyApp {
+>MyApp : Symbol(MyApp, Decl(contextualTypingOfTooShortOverloads.ts, 10, 51))
+
+    use: IRouterHandler<this> & IRouterMatcher<this>;
+>use : Symbol(MyApp.use, Decl(contextualTypingOfTooShortOverloads.ts, 13, 17))
+>IRouterHandler : Symbol(IRouterHandler, Decl(contextualTypingOfTooShortOverloads.ts, 15, 1))
+>IRouterMatcher : Symbol(IRouterMatcher, Decl(contextualTypingOfTooShortOverloads.ts, 20, 1))
+}
+
+interface IRouterHandler<T> {
+>IRouterHandler : Symbol(IRouterHandler, Decl(contextualTypingOfTooShortOverloads.ts, 15, 1))
+>T : Symbol(T, Decl(contextualTypingOfTooShortOverloads.ts, 17, 25))
+
+    (...handlers: RequestHandler[]): T;
+>handlers : Symbol(handlers, Decl(contextualTypingOfTooShortOverloads.ts, 18, 5))
+>RequestHandler : Symbol(RequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 28, 108))
+>T : Symbol(T, Decl(contextualTypingOfTooShortOverloads.ts, 17, 25))
+
+    (...handlers: RequestHandlerParams[]): T;
+>handlers : Symbol(handlers, Decl(contextualTypingOfTooShortOverloads.ts, 19, 5))
+>RequestHandlerParams : Symbol(RequestHandlerParams, Decl(contextualTypingOfTooShortOverloads.ts, 27, 56))
+>T : Symbol(T, Decl(contextualTypingOfTooShortOverloads.ts, 17, 25))
+}
+
+interface IRouterMatcher<T> {
+>IRouterMatcher : Symbol(IRouterMatcher, Decl(contextualTypingOfTooShortOverloads.ts, 20, 1))
+>T : Symbol(T, Decl(contextualTypingOfTooShortOverloads.ts, 22, 25))
+
+    (path: PathParams, ...handlers: RequestHandler[]): T;
+>path : Symbol(path, Decl(contextualTypingOfTooShortOverloads.ts, 23, 5))
+>PathParams : Symbol(PathParams, Decl(contextualTypingOfTooShortOverloads.ts, 25, 1))
+>handlers : Symbol(handlers, Decl(contextualTypingOfTooShortOverloads.ts, 23, 22))
+>RequestHandler : Symbol(RequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 28, 108))
+>T : Symbol(T, Decl(contextualTypingOfTooShortOverloads.ts, 22, 25))
+
+    (path: PathParams, ...handlers: RequestHandlerParams[]): T;
+>path : Symbol(path, Decl(contextualTypingOfTooShortOverloads.ts, 24, 5))
+>PathParams : Symbol(PathParams, Decl(contextualTypingOfTooShortOverloads.ts, 25, 1))
+>handlers : Symbol(handlers, Decl(contextualTypingOfTooShortOverloads.ts, 24, 22))
+>RequestHandlerParams : Symbol(RequestHandlerParams, Decl(contextualTypingOfTooShortOverloads.ts, 27, 56))
+>T : Symbol(T, Decl(contextualTypingOfTooShortOverloads.ts, 22, 25))
+}
+
+type PathParams = string | RegExp | (string | RegExp)[];
+>PathParams : Symbol(PathParams, Decl(contextualTypingOfTooShortOverloads.ts, 25, 1))
+>RegExp : Symbol(RegExp, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>RegExp : Symbol(RegExp, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+type RequestHandlerParams = RequestHandler | ErrorRequestHandler | (RequestHandler | ErrorRequestHandler)[];
+>RequestHandlerParams : Symbol(RequestHandlerParams, Decl(contextualTypingOfTooShortOverloads.ts, 27, 56))
+>RequestHandler : Symbol(RequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 28, 108))
+>ErrorRequestHandler : Symbol(ErrorRequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 32, 1))
+>RequestHandler : Symbol(RequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 28, 108))
+>ErrorRequestHandler : Symbol(ErrorRequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 32, 1))
+
+interface RequestHandler {
+>RequestHandler : Symbol(RequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 28, 108))
+
+    (req: Request, res: Response, next: NextFunction): any;
+>req : Symbol(req, Decl(contextualTypingOfTooShortOverloads.ts, 31, 5))
+>Request : Symbol(Request, Decl(contextualTypingOfTooShortOverloads.ts, 36, 1))
+>res : Symbol(res, Decl(contextualTypingOfTooShortOverloads.ts, 31, 18))
+>Response : Symbol(Response, Decl(contextualTypingOfTooShortOverloads.ts, 40, 1))
+>next : Symbol(next, Decl(contextualTypingOfTooShortOverloads.ts, 31, 33))
+>NextFunction : Symbol(NextFunction, Decl(contextualTypingOfTooShortOverloads.ts, 44, 1))
+}
+
+interface ErrorRequestHandler {
+>ErrorRequestHandler : Symbol(ErrorRequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 32, 1))
+
+    (err: any, req: Request, res: Response, next: NextFunction): any;
+>err : Symbol(err, Decl(contextualTypingOfTooShortOverloads.ts, 35, 5))
+>req : Symbol(req, Decl(contextualTypingOfTooShortOverloads.ts, 35, 14))
+>Request : Symbol(Request, Decl(contextualTypingOfTooShortOverloads.ts, 36, 1))
+>res : Symbol(res, Decl(contextualTypingOfTooShortOverloads.ts, 35, 28))
+>Response : Symbol(Response, Decl(contextualTypingOfTooShortOverloads.ts, 40, 1))
+>next : Symbol(next, Decl(contextualTypingOfTooShortOverloads.ts, 35, 43))
+>NextFunction : Symbol(NextFunction, Decl(contextualTypingOfTooShortOverloads.ts, 44, 1))
+}
+
+interface Request {
+>Request : Symbol(Request, Decl(contextualTypingOfTooShortOverloads.ts, 36, 1))
+
+    method: string;
+>method : Symbol(Request.method, Decl(contextualTypingOfTooShortOverloads.ts, 38, 19))
+}
+
+interface Response {
+>Response : Symbol(Response, Decl(contextualTypingOfTooShortOverloads.ts, 40, 1))
+
+    statusCode: number;
+>statusCode : Symbol(Response.statusCode, Decl(contextualTypingOfTooShortOverloads.ts, 42, 20))
+}
+
+interface NextFunction {
+>NextFunction : Symbol(NextFunction, Decl(contextualTypingOfTooShortOverloads.ts, 44, 1))
+
+    (err?: any): void;
+>err : Symbol(err, Decl(contextualTypingOfTooShortOverloads.ts, 47, 5))
+}
+
diff --git a/tests/baselines/reference/contextualTypingOfTooShortOverloads.types b/tests/baselines/reference/contextualTypingOfTooShortOverloads.types
new file mode 100644
index 0000000000000..9e306da3e61ef
--- /dev/null
+++ b/tests/baselines/reference/contextualTypingOfTooShortOverloads.types
@@ -0,0 +1,143 @@
+=== tests/cases/compiler/contextualTypingOfTooShortOverloads.ts ===
+// small repro from #11875
+var use: Overload;
+>use : Overload
+>Overload : Overload
+
+use((req, res) => {});
+>use((req, res) => {}) : void
+>use : Overload
+>(req, res) => {} : (req: number, res: number) => void
+>req : number
+>res : number
+
+interface Overload {
+>Overload : Overload
+
+    (handler1: (req1: string) => void): void;
+>handler1 : (req1: string) => void
+>req1 : string
+
+    (handler2: (req2: number, res2: number) => void): void;
+>handler2 : (req2: number, res2: number) => void
+>req2 : number
+>res2 : number
+}
+// larger repro from #11875
+let app: MyApp;
+>app : MyApp
+>MyApp : MyApp
+
+app.use((err: any, req, res, next) => { return; });
+>app.use((err: any, req, res, next) => { return; }) : MyApp
+>app.use : IRouterHandler<MyApp> & IRouterMatcher<MyApp>
+>app : MyApp
+>use : IRouterHandler<MyApp> & IRouterMatcher<MyApp>
+>(err: any, req, res, next) => { return; } : (err: any, req: any, res: any, next: any) => void
+>err : any
+>req : any
+>res : any
+>next : any
+
+
+interface MyApp {
+>MyApp : MyApp
+
+    use: IRouterHandler<this> & IRouterMatcher<this>;
+>use : IRouterHandler<this> & IRouterMatcher<this>
+>IRouterHandler : IRouterHandler<T>
+>IRouterMatcher : IRouterMatcher<T>
+}
+
+interface IRouterHandler<T> {
+>IRouterHandler : IRouterHandler<T>
+>T : T
+
+    (...handlers: RequestHandler[]): T;
+>handlers : RequestHandler[]
+>RequestHandler : RequestHandler
+>T : T
+
+    (...handlers: RequestHandlerParams[]): T;
+>handlers : RequestHandlerParams[]
+>RequestHandlerParams : RequestHandlerParams
+>T : T
+}
+
+interface IRouterMatcher<T> {
+>IRouterMatcher : IRouterMatcher<T>
+>T : T
+
+    (path: PathParams, ...handlers: RequestHandler[]): T;
+>path : PathParams
+>PathParams : PathParams
+>handlers : RequestHandler[]
+>RequestHandler : RequestHandler
+>T : T
+
+    (path: PathParams, ...handlers: RequestHandlerParams[]): T;
+>path : PathParams
+>PathParams : PathParams
+>handlers : RequestHandlerParams[]
+>RequestHandlerParams : RequestHandlerParams
+>T : T
+}
+
+type PathParams = string | RegExp | (string | RegExp)[];
+>PathParams : PathParams
+>RegExp : RegExp
+>RegExp : RegExp
+
+type RequestHandlerParams = RequestHandler | ErrorRequestHandler | (RequestHandler | ErrorRequestHandler)[];
+>RequestHandlerParams : RequestHandlerParams
+>RequestHandler : RequestHandler
+>ErrorRequestHandler : ErrorRequestHandler
+>RequestHandler : RequestHandler
+>ErrorRequestHandler : ErrorRequestHandler
+
+interface RequestHandler {
+>RequestHandler : RequestHandler
+
+    (req: Request, res: Response, next: NextFunction): any;
+>req : Request
+>Request : Request
+>res : Response
+>Response : Response
+>next : NextFunction
+>NextFunction : NextFunction
+}
+
+interface ErrorRequestHandler {
+>ErrorRequestHandler : ErrorRequestHandler
+
+    (err: any, req: Request, res: Response, next: NextFunction): any;
+>err : any
+>req : Request
+>Request : Request
+>res : Response
+>Response : Response
+>next : NextFunction
+>NextFunction : NextFunction
+}
+
+interface Request {
+>Request : Request
+
+    method: string;
+>method : string
+}
+
+interface Response {
+>Response : Response
+
+    statusCode: number;
+>statusCode : number
+}
+
+interface NextFunction {
+>NextFunction : NextFunction
+
+    (err?: any): void;
+>err : any
+}
+
diff --git a/tests/baselines/reference/partiallyAnnotatedFunctionInferenceError.errors.txt b/tests/baselines/reference/partiallyAnnotatedFunctionInferenceError.errors.txt
index a9fc9b68cf899..d1e84494fa914 100644
--- a/tests/baselines/reference/partiallyAnnotatedFunctionInferenceError.errors.txt
+++ b/tests/baselines/reference/partiallyAnnotatedFunctionInferenceError.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(12,11): error TS2345: Argument of type '(t1: D, t2: D, t3: any) => void' is not assignable to parameter of type '(t: D, t1: D) => void'.
-tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(13,11): error TS2345: Argument of type '(t1: D, t2: D, t3: any) => void' is not assignable to parameter of type '(t: D, t1: D) => void'.
+tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(12,11): error TS2345: Argument of type '(t1: D, t2: C, t3: any) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.
+tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(13,11): error TS2345: Argument of type '(t1: C, t2: D, t3: any) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.
 tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(14,11): error TS2345: Argument of type '(t1: C, t2: C, t3: D) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.
 
 
@@ -17,10 +17,10 @@ tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partial
     // more args
     testError((t1: D, t2, t3) => {})
               ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2345: Argument of type '(t1: D, t2: D, t3: any) => void' is not assignable to parameter of type '(t: D, t1: D) => void'.
+!!! error TS2345: Argument of type '(t1: D, t2: C, t3: any) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.
     testError((t1, t2: D, t3) => {})
               ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2345: Argument of type '(t1: D, t2: D, t3: any) => void' is not assignable to parameter of type '(t: D, t1: D) => void'.
+!!! error TS2345: Argument of type '(t1: C, t2: D, t3: any) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.
     testError((t1, t2, t3: D) => {})
               ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(t1: C, t2: C, t3: D) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.
diff --git a/tests/cases/compiler/contextualTypingOfTooShortOverloads.ts b/tests/cases/compiler/contextualTypingOfTooShortOverloads.ts
new file mode 100644
index 0000000000000..6fa88a1e5595a
--- /dev/null
+++ b/tests/cases/compiler/contextualTypingOfTooShortOverloads.ts
@@ -0,0 +1,49 @@
+// small repro from #11875
+var use: Overload;
+use((req, res) => {});
+
+interface Overload {
+    (handler1: (req1: string) => void): void;
+    (handler2: (req2: number, res2: number) => void): void;
+}
+// larger repro from #11875
+let app: MyApp;
+app.use((err: any, req, res, next) => { return; });
+
+
+interface MyApp {
+    use: IRouterHandler<this> & IRouterMatcher<this>;
+}
+
+interface IRouterHandler<T> {
+    (...handlers: RequestHandler[]): T;
+    (...handlers: RequestHandlerParams[]): T;
+}
+
+interface IRouterMatcher<T> {
+    (path: PathParams, ...handlers: RequestHandler[]): T;
+    (path: PathParams, ...handlers: RequestHandlerParams[]): T;
+}
+
+type PathParams = string | RegExp | (string | RegExp)[];
+type RequestHandlerParams = RequestHandler | ErrorRequestHandler | (RequestHandler | ErrorRequestHandler)[];
+
+interface RequestHandler {
+    (req: Request, res: Response, next: NextFunction): any;
+}
+
+interface ErrorRequestHandler {
+    (err: any, req: Request, res: Response, next: NextFunction): any;
+}
+
+interface Request {
+    method: string;
+}
+
+interface Response {
+    statusCode: number;
+}
+
+interface NextFunction {
+    (err?: any): void;
+}

From 5a336fedbaf6d87896c1b3bc928ceb5377c99fec Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 27 Oct 2016 15:38:29 -0700
Subject: [PATCH 107/224] Minor style improvements

---
 src/compiler/checker.ts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 7cf61a7131786..db1f3a5bd8f80 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -11891,7 +11891,8 @@ namespace ts {
                     // for the argument. In that case, we should check the argument.
                     if (argType === undefined) {
                         // If the parameter and argument are both functions and the parameter has fewer arguments than the argument,
-                        // then this signature is not applicable. Exit early.
+                        // then this signature is not applicable. Exit early to avoid fixing incorrect
+                        // contextual types to the function expression parameters.
                         if (!reportErrors && isAritySmaller(paramType, arg)) {
                             return false;
                         }
@@ -11922,6 +11923,8 @@ namespace ts {
                 const sourceLengths = sourceSignatures.map(sig => !sig.hasRestParameter ? sig.parameters.length : Number.MAX_VALUE);
                 return forEach(sourceLengths, len => len < targetParameterCount);
             }
+
+            return false;
         }
 
         /**

From 3e71d50708759c0180e45657fe7714036e3f0415 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 27 Oct 2016 15:42:41 -0700
Subject: [PATCH 108/224] Ignore optionality when skipping overloads

---
 src/compiler/checker.ts                                  | 9 +--------
 ...genericCallWithOverloadedFunctionTypedArguments.types | 4 ++--
 2 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index db1f3a5bd8f80..812c55d0ea252 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -11912,16 +11912,9 @@ namespace ts {
 
         function isAritySmaller(sourceType: Type, target: Expression) {
             if (isFunctionExpressionOrArrowFunction(target) && isFunctionType(sourceType)) {
-                let targetParameterCount = 0;
-                for (; targetParameterCount < target.parameters.length; targetParameterCount++) {
-                    const param = target.parameters[targetParameterCount];
-                    if (param.initializer || param.questionToken || param.dotDotDotToken || isJSDocOptionalParameter(param)) {
-                        break;
-                    }
-                }
                 const sourceSignatures = getSignaturesOfType(sourceType, SignatureKind.Call);
                 const sourceLengths = sourceSignatures.map(sig => !sig.hasRestParameter ? sig.parameters.length : Number.MAX_VALUE);
-                return forEach(sourceLengths, len => len < targetParameterCount);
+                return forEach(sourceLengths, len => len < target.parameters.length);
             }
 
             return false;
diff --git a/tests/baselines/reference/genericCallWithOverloadedFunctionTypedArguments.types b/tests/baselines/reference/genericCallWithOverloadedFunctionTypedArguments.types
index ab07e9c880a61..c26370a7640a5 100644
--- a/tests/baselines/reference/genericCallWithOverloadedFunctionTypedArguments.types
+++ b/tests/baselines/reference/genericCallWithOverloadedFunctionTypedArguments.types
@@ -122,8 +122,8 @@ module GenericParameter {
 >'' : ""
 
     var r11 = foo6(<T>(x: T, y?: T) => ''); // any => string (+1 overload)
->r11 : { (x: any): string; (x: any, y?: any): string; }
->foo6(<T>(x: T, y?: T) => '') : { (x: any): string; (x: any, y?: any): string; }
+>r11 : any
+>foo6(<T>(x: T, y?: T) => '') : any
 >foo6 : <T>(cb: { (x: T): string; (x: T, y?: T): string; }) => { (x: T): string; (x: T, y?: T): string; }
 ><T>(x: T, y?: T) => '' : <T>(x: T, y?: T) => string
 >T : T

From 12f6dcefa1d31379ae25563967457e87ac8ad772 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 27 Oct 2016 15:50:21 -0700
Subject: [PATCH 109/224] Revert "Merge pull request #11354 from
 Microsoft/map4"

This reverts commit adfdae0dc47db5ad8248d26929a7b31cb895a539, reversing
changes made to aad663cebf6a89f7029af57d8cb6a0a011854978.
---
 Jakefile.js                                   |   2 -
 scripts/processDiagnosticMessages.ts          |  18 +-
 src/compiler/binder.ts                        |  44 +-
 src/compiler/checker.ts                       | 488 +++++++-------
 src/compiler/collections.ts                   | 609 ------------------
 src/compiler/commandLineParser.ts             | 128 ++--
 src/compiler/core.ts                          | 287 ++++++++-
 src/compiler/declarationEmitter.ts            |  18 +-
 src/compiler/emitter.ts                       |  18 +-
 src/compiler/factory.ts                       |  20 +-
 src/compiler/parser.ts                        |   6 +-
 src/compiler/performance.ts                   |  30 +-
 src/compiler/program.ts                       |  72 ++-
 src/compiler/scanner.ts                       |  21 +-
 src/compiler/sourcemap.ts                     |   2 +-
 src/compiler/sys.ts                           |  21 +-
 src/compiler/transformer.ts                   |  18 +-
 src/compiler/transformers/es2015.ts           |  33 +-
 src/compiler/transformers/generators.ts       |  32 +-
 src/compiler/transformers/jsx.ts              |   8 +-
 src/compiler/transformers/module/module.ts    |  57 +-
 src/compiler/transformers/module/system.ts    |  63 +-
 src/compiler/transformers/ts.ts               |  24 +-
 src/compiler/tsc.ts                           |  34 +-
 src/compiler/tsconfig.json                    |   1 -
 src/compiler/types.ts                         |  73 +--
 src/compiler/utilities.ts                     |  86 +--
 src/compiler/visitor.ts                       |  54 +-
 src/harness/fourslash.ts                      |  47 +-
 src/harness/harness.ts                        |  30 +-
 src/harness/harnessLanguageService.ts         |   4 +-
 src/harness/loggedIO.ts                       |  10 +-
 src/harness/projectsRunner.ts                 |  21 +-
 .../unittests/cachingInServerLSHost.ts        |  23 +-
 src/harness/unittests/moduleResolution.ts     |  64 +-
 .../unittests/reuseProgramStructure.ts        |  27 +-
 src/harness/unittests/session.ts              |  22 +-
 .../unittests/tsserverProjectSystem.ts        |  37 +-
 src/harness/unittests/typingsInstaller.ts     |   4 +-
 src/server/builder.ts                         |  15 +-
 src/server/client.ts                          |   8 +-
 src/server/editorServices.ts                  | 140 ++--
 src/server/lsHost.ts                          |  14 +-
 src/server/project.ts                         |  59 +-
 src/server/scriptInfo.ts                      |   2 +-
 src/server/session.ts                         |   8 +-
 src/server/tsconfig.library.json              |   2 +-
 src/server/typingsCache.ts                    |  29 +-
 .../typingsInstaller/typingsInstaller.ts      |  38 +-
 src/server/utilities.ts                       |  41 +-
 src/services/classifier.ts                    |   6 +-
 src/services/codefixes/codeFixProvider.ts     |  17 +-
 src/services/completions.ts                   |  55 +-
 src/services/documentHighlights.ts            |   6 +-
 src/services/documentRegistry.ts              |  39 +-
 src/services/findAllReferences.ts             |  31 +-
 src/services/formatting/rules.ts              |   2 +-
 src/services/goToDefinition.ts                |   2 +-
 src/services/jsTyping.ts                      |  51 +-
 src/services/navigateTo.ts                    |  19 +-
 src/services/navigationBar.ts                 |  18 +-
 src/services/patternMatcher.ts                |   8 +-
 src/services/services.ts                      |  28 +-
 src/services/shims.ts                         |   2 +-
 src/services/signatureHelp.ts                 |   2 +-
 src/services/transpile.ts                     |   6 +-
 src/services/types.ts                         |   4 +-
 tslint.json                                   |   3 +-
 68 files changed, 1430 insertions(+), 1781 deletions(-)
 delete mode 100644 src/compiler/collections.ts

diff --git a/Jakefile.js b/Jakefile.js
index 8425751c4d41c..8ce70eb353f9e 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -57,7 +57,6 @@ function measure(marker) {
 }
 
 var compilerSources = [
-    "collections.ts",
     "core.ts",
     "performance.ts",
     "sys.ts",
@@ -94,7 +93,6 @@ var compilerSources = [
 });
 
 var servicesSources = [
-    "collections.ts",
     "core.ts",
     "performance.ts",
     "sys.ts",
diff --git a/scripts/processDiagnosticMessages.ts b/scripts/processDiagnosticMessages.ts
index a7e2f24fdb885..e5eaa46c8e5b9 100644
--- a/scripts/processDiagnosticMessages.ts
+++ b/scripts/processDiagnosticMessages.ts
@@ -27,7 +27,7 @@ function main(): void {
 
     var inputFilePath = sys.args[0].replace(/\\/g, "/");
     var inputStr = sys.readFile(inputFilePath);
-
+    
     var diagnosticMessages: InputDiagnosticMessageTable = JSON.parse(inputStr);
 
     var names = Utilities.getObjectKeys(diagnosticMessages);
@@ -44,7 +44,7 @@ function main(): void {
 function checkForUniqueCodes(messages: string[], diagnosticTable: InputDiagnosticMessageTable) {
     const originalMessageForCode: string[] = [];
     let numConflicts = 0;
-
+    
     for (const currentMessage of messages) {
         const code = diagnosticTable[currentMessage].code;
 
@@ -68,19 +68,19 @@ function checkForUniqueCodes(messages: string[], diagnosticTable: InputDiagnosti
     }
 }
 
-function buildUniqueNameMap(names: string[]): ts.Map<string, string> {
-    var nameMap = ts.createMap<string, string>();
+function buildUniqueNameMap(names: string[]): ts.Map<string> {
+    var nameMap = ts.createMap<string>();
 
     var uniqueNames = NameGenerator.ensureUniqueness(names, /* isCaseSensitive */ false, /* isFixed */ undefined);
 
     for (var i = 0; i < names.length; i++) {
-        nameMap.set(names[i], uniqueNames[i]);
+        nameMap[names[i]] = uniqueNames[i];
     }
 
     return nameMap;
 }
 
-function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable, nameMap: ts.Map<string, string>): string {
+function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable, nameMap: ts.Map<string>): string {
     var result =
         '// <auto-generated />\r\n' +
         '/// <reference path="types.ts" />\r\n' +
@@ -91,7 +91,7 @@ function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable, nameMap:
     for (var i = 0; i < names.length; i++) {
         var name = names[i];
         var diagnosticDetails = messageTable[name];
-        var propName = convertPropertyName(nameMap.get(name));
+        var propName = convertPropertyName(nameMap[name]);
 
         result +=
         '        ' + propName +
@@ -107,14 +107,14 @@ function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable, nameMap:
     return result;
 }
 
-function buildDiagnosticMessageOutput(messageTable: InputDiagnosticMessageTable, nameMap: ts.Map<string, string>): string {
+function buildDiagnosticMessageOutput(messageTable: InputDiagnosticMessageTable, nameMap: ts.Map<string>): string {
     var result =
         '{';
     var names = Utilities.getObjectKeys(messageTable);
     for (var i = 0; i < names.length; i++) {
         var name = names[i];
         var diagnosticDetails = messageTable[name];
-        var propName = convertPropertyName(nameMap.get(name));
+        var propName = convertPropertyName(nameMap[name]);
 
         result += '\r\n  "' + createKey(propName, diagnosticDetails.code) + '"' + ' : "' + name.replace(/[\"]/g, '\\"') + '"';
         if (i !== names.length - 1) {
diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 9bf8d4846ce12..9c2c749e112a6 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -133,7 +133,7 @@ namespace ts {
 
         let symbolCount = 0;
         let Symbol: { new (flags: SymbolFlags, name: string): Symbol };
-        let classifiableNames: Set<string>;
+        let classifiableNames: Map<string>;
 
         const unreachableFlow: FlowNode = { flags: FlowFlags.Unreachable };
         const reportedUnreachableFlow: FlowNode = { flags: FlowFlags.Unreachable };
@@ -147,7 +147,7 @@ namespace ts {
             options = opts;
             languageVersion = getEmitScriptTarget(options);
             inStrictMode = bindInStrictMode(file, opts);
-            classifiableNames = createSet();
+            classifiableNames = createMap<string>();
             symbolCount = 0;
             skipTransformFlagAggregation = isDeclarationFile(file);
 
@@ -207,11 +207,11 @@ namespace ts {
             symbol.declarations.push(node);
 
             if (symbolFlags & SymbolFlags.HasExports && !symbol.exports) {
-                symbol.exports = createMap<string, Symbol>();
+                symbol.exports = createMap<Symbol>();
             }
 
             if (symbolFlags & SymbolFlags.HasMembers && !symbol.members) {
-                symbol.members = createMap<string, Symbol>();
+                symbol.members = createMap<Symbol>();
             }
 
             if (symbolFlags & SymbolFlags.Value) {
@@ -349,17 +349,17 @@ namespace ts {
                 // Otherwise, we'll be merging into a compatible existing symbol (for example when
                 // you have multiple 'vars' with the same name in the same container).  In this case
                 // just add this node into the declarations list of the symbol.
-                symbol = getOrUpdate(symbolTable, name, name => createSymbol(SymbolFlags.None, name));
+                symbol = symbolTable[name] || (symbolTable[name] = createSymbol(SymbolFlags.None, name));
 
                 if (name && (includes & SymbolFlags.Classifiable)) {
-                    classifiableNames.add(name);
+                    classifiableNames[name] = name;
                 }
 
                 if (symbol.flags & excludes) {
                     if (symbol.isReplaceableByMethod) {
                         // Javascript constructor-declared symbols can be discarded in favor of
                         // prototype symbols like methods.
-                        symbol = setAndReturn(symbolTable, name, createSymbol(SymbolFlags.None, name));
+                        symbol = symbolTable[name] = createSymbol(SymbolFlags.None, name);
                     }
                     else {
                         if (node.name) {
@@ -484,7 +484,7 @@ namespace ts {
             if (containerFlags & ContainerFlags.IsContainer) {
                 container = blockScopeContainer = node;
                 if (containerFlags & ContainerFlags.HasLocals) {
-                    container.locals = createMap<string, Symbol>();
+                    container.locals = createMap<Symbol>();
                 }
                 addToContainerChain(container);
             }
@@ -1525,7 +1525,8 @@ namespace ts {
 
             const typeLiteralSymbol = createSymbol(SymbolFlags.TypeLiteral, "__type");
             addDeclarationToSymbol(typeLiteralSymbol, node, SymbolFlags.TypeLiteral);
-            typeLiteralSymbol.members = createMap([[symbol.name, symbol]]);
+            typeLiteralSymbol.members = createMap<Symbol>();
+            typeLiteralSymbol.members[symbol.name] = symbol;
         }
 
         function bindObjectLiteralExpression(node: ObjectLiteralExpression) {
@@ -1535,7 +1536,7 @@ namespace ts {
             }
 
             if (inStrictMode) {
-                const seen = createMap<string, ElementKind>();
+                const seen = createMap<ElementKind>();
 
                 for (const prop of node.properties) {
                     if (prop.name.kind !== SyntaxKind.Identifier) {
@@ -1556,9 +1557,9 @@ namespace ts {
                         ? ElementKind.Property
                         : ElementKind.Accessor;
 
-                    const existingKind = seen.get(identifier.text);
+                    const existingKind = seen[identifier.text];
                     if (!existingKind) {
-                        seen.set(identifier.text, currentKind);
+                        seen[identifier.text] = currentKind;
                         continue;
                     }
 
@@ -1591,7 +1592,7 @@ namespace ts {
                 // fall through.
                 default:
                     if (!blockScopeContainer.locals) {
-                        blockScopeContainer.locals = createMap<string, Symbol>();
+                        blockScopeContainer.locals = createMap<Symbol>();
                         addToContainerChain(blockScopeContainer);
                     }
                     declareSymbol(blockScopeContainer.locals, undefined, node, symbolFlags, symbolExcludes);
@@ -2071,7 +2072,7 @@ namespace ts {
                 }
             }
 
-            file.symbol.globalExports = file.symbol.globalExports || createMap<string, Symbol>();
+            file.symbol.globalExports = file.symbol.globalExports || createMap<Symbol>();
             declareSymbol(file.symbol.globalExports, file.symbol, node, SymbolFlags.Alias, SymbolFlags.AliasExcludes);
         }
 
@@ -2118,7 +2119,7 @@ namespace ts {
             Debug.assert(isInJavaScriptFile(node));
             // Declare a 'member' if the container is an ES5 class or ES6 constructor
             if (container.kind === SyntaxKind.FunctionDeclaration || container.kind === SyntaxKind.FunctionExpression) {
-                container.symbol.members = container.symbol.members || createMap<string, Symbol>();
+                container.symbol.members = container.symbol.members || createMap<Symbol>();
                 // It's acceptable for multiple 'this' assignments of the same identifier to occur
                 declareSymbol(container.symbol.members, container.symbol, node, SymbolFlags.Property, SymbolFlags.PropertyExcludes & ~SymbolFlags.Property);
             }
@@ -2150,14 +2151,14 @@ namespace ts {
             constructorFunction.parent = classPrototype;
             classPrototype.parent = leftSideOfAssignment;
 
-            const funcSymbol = container.locals.get(constructorFunction.text);
+            const funcSymbol = container.locals[constructorFunction.text];
             if (!funcSymbol || !(funcSymbol.flags & SymbolFlags.Function || isDeclarationOfFunctionExpression(funcSymbol))) {
                 return;
             }
 
             // Set up the members collection if it doesn't exist already
             if (!funcSymbol.members) {
-                funcSymbol.members = createMap<string, Symbol>();
+                funcSymbol.members = createMap<Symbol>();
             }
 
             // Declare the method/property
@@ -2190,7 +2191,7 @@ namespace ts {
                 bindAnonymousDeclaration(node, SymbolFlags.Class, bindingName);
                 // Add name of class expression into the map for semantic classifier
                 if (node.name) {
-                    classifiableNames.add(node.name.text);
+                    classifiableNames[node.name.text] = node.name.text;
                 }
             }
 
@@ -2206,15 +2207,14 @@ namespace ts {
             // module might have an exported variable called 'prototype'.  We can't allow that as
             // that would clash with the built-in 'prototype' for the class.
             const prototypeSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Prototype, "prototype");
-            const symbolExport = symbol.exports.get(prototypeSymbol.name);
-            if (symbolExport) {
+            if (symbol.exports[prototypeSymbol.name]) {
                 if (node.name) {
                     node.name.parent = node;
                 }
-                file.bindDiagnostics.push(createDiagnosticForNode(symbolExport.declarations[0],
+                file.bindDiagnostics.push(createDiagnosticForNode(symbol.exports[prototypeSymbol.name].declarations[0],
                     Diagnostics.Duplicate_identifier_0, prototypeSymbol.name));
             }
-            symbol.exports.set(prototypeSymbol.name, prototypeSymbol);
+            symbol.exports[prototypeSymbol.name] = prototypeSymbol;
             prototypeSymbol.parent = symbol;
         }
 
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 281190d325653..4f8f9b3f68c7c 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -47,7 +47,7 @@ namespace ts {
         let symbolCount = 0;
 
         const emptyArray: any[] = [];
-        const emptySymbols = createMap<string, Symbol>();
+        const emptySymbols = createMap<Symbol>();
 
         const compilerOptions = host.getCompilerOptions();
         const languageVersion = compilerOptions.target || ScriptTarget.ES3;
@@ -111,10 +111,10 @@ namespace ts {
         };
 
         const tupleTypes: GenericType[] = [];
-        const unionTypes = createMap<string, UnionType>();
-        const intersectionTypes = createMap<string, IntersectionType>();
-        const stringLiteralTypes = createMap<string, LiteralType>();
-        const numericLiteralTypes = createMap<string, LiteralType>();
+        const unionTypes = createMap<UnionType>();
+        const intersectionTypes = createMap<IntersectionType>();
+        const stringLiteralTypes = createMap<LiteralType>();
+        const numericLiteralTypes = createMap<LiteralType>();
         const evolvingArrayTypes: EvolvingArrayType[] = [];
 
         const unknownSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Transient, "unknown");
@@ -139,7 +139,7 @@ namespace ts {
 
         const emptyObjectType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
         const emptyGenericType = <GenericType><ObjectType>createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
-        emptyGenericType.instantiations = createMap<string, TypeReference>();
+        emptyGenericType.instantiations = createMap<TypeReference>();
 
         const anyFunctionType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
         // The anyFunctionType contains the anyFunctionType by definition. The flag is further propagated
@@ -155,7 +155,7 @@ namespace ts {
 
         const enumNumberIndexInfo = createIndexInfo(stringType, /*isReadonly*/ true);
 
-        const globals = createMap<string, Symbol>();
+        const globals = createMap<Symbol>();
         /**
          * List of every ambient module with a "*" wildcard.
          * Unlike other ambient modules, these can't be stored in `globals` because symbol tables only deal with exact matches.
@@ -221,7 +221,7 @@ namespace ts {
         const mergedSymbols: Symbol[] = [];
         const symbolLinks: SymbolLinks[] = [];
         const nodeLinks: NodeLinks[] = [];
-        const flowLoopCaches: Map<string, Type>[] = [];
+        const flowLoopCaches: Map<Type>[] = [];
         const flowLoopNodes: FlowNode[] = [];
         const flowLoopKeys: string[] = [];
         const flowLoopTypes: Type[][] = [];
@@ -295,7 +295,7 @@ namespace ts {
             NullFacts = TypeofEQObject | TypeofNEString | TypeofNENumber | TypeofNEBoolean | TypeofNESymbol | TypeofNEFunction | TypeofNEHostObject | EQNull | EQUndefinedOrNull | NEUndefined | Falsy,
         }
 
-        const typeofEQFacts = mapOfMapLike({
+        const typeofEQFacts = createMap({
             "string": TypeFacts.TypeofEQString,
             "number": TypeFacts.TypeofEQNumber,
             "boolean": TypeFacts.TypeofEQBoolean,
@@ -305,7 +305,7 @@ namespace ts {
             "function": TypeFacts.TypeofEQFunction
         });
 
-        const typeofNEFacts = mapOfMapLike({
+        const typeofNEFacts = createMap({
             "string": TypeFacts.TypeofNEString,
             "number": TypeFacts.TypeofNENumber,
             "boolean": TypeFacts.TypeofNEBoolean,
@@ -315,7 +315,7 @@ namespace ts {
             "function": TypeFacts.TypeofNEFunction
         });
 
-        const typeofTypesByName = mapOfMapLike<Type>({
+        const typeofTypesByName = createMap<Type>({
             "string": stringType,
             "number": numberType,
             "boolean": booleanType,
@@ -325,7 +325,7 @@ namespace ts {
 
         let jsxElementType: Type;
         /** Things we lazy load from the JSX namespace */
-        const jsxTypes = createMap<string, Type>();
+        const jsxTypes = createMap<Type>();
         const JsxNames = {
             JSX: "JSX",
             IntrinsicElements: "IntrinsicElements",
@@ -336,11 +336,11 @@ namespace ts {
             IntrinsicClassAttributes: "IntrinsicClassAttributes"
         };
 
-        const subtypeRelation = createMap<string, RelationComparisonResult>();
-        const assignableRelation = createMap<string, RelationComparisonResult>();
-        const comparableRelation = createMap<string, RelationComparisonResult>();
-        const identityRelation = createMap<string, RelationComparisonResult>();
-        const enumRelation = createMap<string, boolean>();
+        const subtypeRelation = createMap<RelationComparisonResult>();
+        const assignableRelation = createMap<RelationComparisonResult>();
+        const comparableRelation = createMap<RelationComparisonResult>();
+        const identityRelation = createMap<RelationComparisonResult>();
+        const enumRelation = createMap<boolean>();
 
         // This is for caching the result of getSymbolDisplayBuilder. Do not access directly.
         let _displayBuilder: SymbolDisplayBuilder;
@@ -354,7 +354,8 @@ namespace ts {
             ResolvedReturnType
         }
 
-        const builtinGlobals = createMap([[undefinedSymbol.name, undefinedSymbol]]);
+        const builtinGlobals = createMap<Symbol>();
+        builtinGlobals[undefinedSymbol.name] = undefinedSymbol;
 
         initializeTypeChecker();
 
@@ -437,11 +438,11 @@ namespace ts {
                     target.declarations.push(node);
                 });
                 if (source.members) {
-                    if (!target.members) target.members = createMap<string, Symbol>();
+                    if (!target.members) target.members = createMap<Symbol>();
                     mergeSymbolTable(target.members, source.members);
                 }
                 if (source.exports) {
-                    if (!target.exports) target.exports = createMap<string, Symbol>();
+                    if (!target.exports) target.exports = createMap<Symbol>();
                     mergeSymbolTable(target.exports, source.exports);
                 }
                 recordMergedSymbol(target, source);
@@ -459,18 +460,18 @@ namespace ts {
         }
 
         function mergeSymbolTable(target: SymbolTable, source: SymbolTable) {
-            source.forEach((sourceSymbol, id) => {
-                let targetSymbol = target.get(id);
+            for (const id in source) {
+                let targetSymbol = target[id];
                 if (!targetSymbol) {
-                    target.set(id, sourceSymbol);
+                    target[id] = source[id];
                 }
                 else {
                     if (!(targetSymbol.flags & SymbolFlags.Merged)) {
-                        target.set(id, targetSymbol = cloneSymbol(targetSymbol));
+                        target[id] = targetSymbol = cloneSymbol(targetSymbol);
                     }
-                    mergeSymbol(targetSymbol, sourceSymbol);
+                    mergeSymbol(targetSymbol, source[id]);
                 }
-            });
+            }
         }
 
         function mergeModuleAugmentation(moduleName: LiteralExpression): void {
@@ -511,16 +512,15 @@ namespace ts {
         }
 
         function addToSymbolTable(target: SymbolTable, source: SymbolTable, message: DiagnosticMessage) {
-            source.forEach((sourceSymbol, id) => {
-                const symbol = target.get(id);
-                if (symbol) {
+            for (const id in source) {
+                if (target[id]) {
                     // Error on redeclarations
-                    forEach(symbol.declarations, addDeclarationDiagnostic(id, message));
+                    forEach(target[id].declarations, addDeclarationDiagnostic(id, message));
                 }
                 else {
-                    target.set(id, sourceSymbol);
+                    target[id] = source[id];
                 }
-            });
+            }
 
             function addDeclarationDiagnostic(id: string, message: DiagnosticMessage) {
                 return (declaration: Declaration) => diagnostics.add(createDiagnosticForNode(declaration, message, id));
@@ -548,7 +548,7 @@ namespace ts {
 
         function getSymbol(symbols: SymbolTable, name: string, meaning: SymbolFlags): Symbol {
             if (meaning) {
-                const symbol = symbols.get(name);
+                const symbol = symbols[name];
                 if (symbol) {
                     Debug.assert((symbol.flags & SymbolFlags.Instantiated) === 0, "Should never get an instantiated symbol here.");
                     if (symbol.flags & meaning) {
@@ -733,7 +733,7 @@ namespace ts {
 
                             // It's an external module. First see if the module has an export default and if the local
                             // name of that export default matches.
-                            if (result = moduleExports.get("default")) {
+                            if (result = moduleExports["default"]) {
                                 const localSymbol = getLocalSymbolForExportDefault(result);
                                 if (localSymbol && (result.flags & meaning) && localSymbol.name === name) {
                                     break loop;
@@ -752,10 +752,9 @@ namespace ts {
                             //     2. We check === SymbolFlags.Alias in order to check that the symbol is *purely*
                             //        an alias. If we used &, we'd be throwing out symbols that have non alias aspects,
                             //        which is not the desired behavior.
-                            const moduleExport = moduleExports.get(name);
-                            if (moduleExport &&
-                                moduleExport.flags === SymbolFlags.Alias &&
-                                getDeclarationOfKind(moduleExport, SyntaxKind.ExportSpecifier)) {
+                            if (moduleExports[name] &&
+                                moduleExports[name].flags === SymbolFlags.Alias &&
+                                getDeclarationOfKind(moduleExports[name], SyntaxKind.ExportSpecifier)) {
                                 break;
                             }
                         }
@@ -1070,16 +1069,11 @@ namespace ts {
             const moduleSymbol = resolveExternalModuleName(node, (<ImportDeclaration>node.parent).moduleSpecifier);
 
             if (moduleSymbol) {
-                let exportDefaultSymbol: Symbol;
-                if (isUntypedModuleSymbol(moduleSymbol)) {
-                    exportDefaultSymbol = moduleSymbol;
-                }
-                else {
-                    const exportValue = moduleSymbol.exports.get("export=");
-                    exportDefaultSymbol = exportValue
-                        ? getPropertyOfType(getTypeOfSymbol(exportValue), "default")
-                        : resolveSymbol(moduleSymbol.exports.get("default"));
-                }
+                const exportDefaultSymbol = isUntypedModuleSymbol(moduleSymbol) ?
+                    moduleSymbol :
+                    moduleSymbol.exports["export="] ?
+                        getPropertyOfType(getTypeOfSymbol(moduleSymbol.exports["export="]), "default") :
+                        resolveSymbol(moduleSymbol.exports["default"]);
 
                 if (!exportDefaultSymbol && !allowSyntheticDefaultImports) {
                     error(node.name, Diagnostics.Module_0_has_no_default_export, symbolToString(moduleSymbol));
@@ -1129,7 +1123,7 @@ namespace ts {
 
         function getExportOfModule(symbol: Symbol, name: string): Symbol {
             if (symbol.flags & SymbolFlags.Module) {
-                const exportedSymbol = getExportsOfSymbol(symbol).get(name);
+                const exportedSymbol = getExportsOfSymbol(symbol)[name];
                 if (exportedSymbol) {
                     return resolveSymbol(exportedSymbol);
                 }
@@ -1157,7 +1151,7 @@ namespace ts {
 
                     let symbolFromVariable: Symbol;
                     // First check if module was specified with "export=". If so, get the member from the resolved type
-                    if (moduleSymbol && moduleSymbol.exports && moduleSymbol.exports.get("export=")) {
+                    if (moduleSymbol && moduleSymbol.exports && moduleSymbol.exports["export="]) {
                         symbolFromVariable = getPropertyOfType(getTypeOfSymbol(targetSymbol), name.text);
                     }
                     else {
@@ -1418,9 +1412,9 @@ namespace ts {
                 // This provides a name to the module. See the test tests/cases/fourslash/untypedModuleImport.ts
                 const newSymbol = createSymbol(SymbolFlags.ValueModule, quotedName);
                 // Module symbols are expected to have 'exports', although since this is an untyped module it can be empty.
-                newSymbol.exports = createMap<string, Symbol>();
+                newSymbol.exports = createMap<Symbol>();
                 // Cache it so subsequent accesses will return the same module.
-                globals.set(quotedName, newSymbol);
+                globals[quotedName] = newSymbol;
                 return newSymbol;
             }
 
@@ -1446,7 +1440,7 @@ namespace ts {
         // An external module with an 'export =' declaration resolves to the target of the 'export =' declaration,
         // and an external module with no 'export =' declaration resolves to the module itself.
         function resolveExternalModuleSymbol(moduleSymbol: Symbol): Symbol {
-            return moduleSymbol && getMergedSymbol(resolveSymbol(moduleSymbol.exports.get("export="))) || moduleSymbol;
+            return moduleSymbol && getMergedSymbol(resolveSymbol(moduleSymbol.exports["export="])) || moduleSymbol;
         }
 
         // An external module with an 'export =' declaration may be referenced as an ES6 module provided the 'export ='
@@ -1462,7 +1456,7 @@ namespace ts {
         }
 
         function hasExportAssignmentSymbol(moduleSymbol: Symbol): boolean {
-            return moduleSymbol.exports.get("export=") !== undefined;
+            return moduleSymbol.exports["export="] !== undefined;
         }
 
         function getExportsOfModuleAsArray(moduleSymbol: Symbol): Symbol[] {
@@ -1487,29 +1481,25 @@ namespace ts {
          * Extends one symbol table with another while collecting information on name collisions for error message generation into the `lookupTable` argument
          * Not passing `lookupTable` and `exportNode` disables this collection, and just extends the tables
          */
-        function extendExportSymbols(target: SymbolTable, source: SymbolTable, lookupTable?: Map<string, ExportCollisionTracker>, exportNode?: ExportDeclaration) {
-            if (!source) return;
-
-            source.forEach((sourceSymbol, id) => {
-                const targetSymbol = target.get(id);
-                if (id !== "default" && !targetSymbol) {
-                    target.set(id, sourceSymbol);
+        function extendExportSymbols(target: SymbolTable, source: SymbolTable, lookupTable?: Map<ExportCollisionTracker>, exportNode?: ExportDeclaration) {
+            for (const id in source) {
+                if (id !== "default" && !target[id]) {
+                    target[id] = source[id];
                     if (lookupTable && exportNode) {
-                        lookupTable.set(id, {
+                        lookupTable[id] = {
                             specifierText: getTextOfNode(exportNode.moduleSpecifier)
-                        } as ExportCollisionTracker);
+                        } as ExportCollisionTracker;
                     }
                 }
-                else if (lookupTable && exportNode && id !== "default" && targetSymbol && resolveSymbol(targetSymbol) !== resolveSymbol(sourceSymbol)) {
-                    const collisionTracker = lookupTable.get(id);
-                    if (!collisionTracker.exportsWithDuplicate) {
-                        collisionTracker.exportsWithDuplicate = [exportNode];
+                else if (lookupTable && exportNode && id !== "default" && target[id] && resolveSymbol(target[id]) !== resolveSymbol(source[id])) {
+                    if (!lookupTable[id].exportsWithDuplicate) {
+                        lookupTable[id].exportsWithDuplicate = [exportNode];
                     }
                     else {
-                        collisionTracker.exportsWithDuplicate.push(exportNode);
+                        lookupTable[id].exportsWithDuplicate.push(exportNode);
                     }
                 }
-            });
+            }
         }
 
         function getExportsForModule(moduleSymbol: Symbol): SymbolTable {
@@ -1529,10 +1519,10 @@ namespace ts {
                 visitedSymbols.push(symbol);
                 const symbols = cloneMap(symbol.exports);
                 // All export * declarations are collected in an __export symbol by the binder
-                const exportStars = symbol.exports.get("__export");
+                const exportStars = symbol.exports["__export"];
                 if (exportStars) {
-                    const nestedSymbols = createMap<string, Symbol>();
-                    const lookupTable = createMap<string, ExportCollisionTracker>();
+                    const nestedSymbols = createMap<Symbol>();
+                    const lookupTable = createMap<ExportCollisionTracker>();
                     for (const node of exportStars.declarations) {
                         const resolvedModule = resolveExternalModuleName(node, (node as ExportDeclaration).moduleSpecifier);
                         const exportedSymbols = visit(resolvedModule);
@@ -1543,20 +1533,21 @@ namespace ts {
                             node as ExportDeclaration
                         );
                     }
-                    lookupTable.forEach(({ exportsWithDuplicate }, id) => {
+                    for (const id in lookupTable) {
+                        const { exportsWithDuplicate } = lookupTable[id];
                         // It's not an error if the file with multiple `export *`s with duplicate names exports a member with that name itself
-                        if (id === "export=" || !(exportsWithDuplicate && exportsWithDuplicate.length) || symbols.get(id)) {
-                            return;
+                        if (id === "export=" || !(exportsWithDuplicate && exportsWithDuplicate.length) || symbols[id]) {
+                            continue;
                         }
                         for (const node of exportsWithDuplicate) {
                             diagnostics.add(createDiagnosticForNode(
                                 node,
                                 Diagnostics.Module_0_has_already_exported_a_member_named_1_Consider_explicitly_re_exporting_to_resolve_the_ambiguity,
-                                lookupTable.get(id).specifierText,
+                                lookupTable[id].specifierText,
                                 id
                             ));
                         }
-                    });
+                    }
                     extendExportSymbols(symbols, nestedSymbols);
                 }
                 return symbols;
@@ -1651,14 +1642,15 @@ namespace ts {
 
         function getNamedMembers(members: SymbolTable): Symbol[] {
             let result: Symbol[];
-            members.forEach((symbol, id) => {
+            for (const id in members) {
                 if (!isReservedMemberName(id)) {
                     if (!result) result = [];
+                    const symbol = members[id];
                     if (symbolIsValue(symbol)) {
                         result.push(symbol);
                     }
                 }
-            });
+            }
             return result || emptyArray;
         }
 
@@ -1731,12 +1723,12 @@ namespace ts {
                 }
 
                 // If symbol is directly available by its name in the symbol table
-                if (isAccessible(symbols.get(symbol.name))) {
+                if (isAccessible(symbols[symbol.name])) {
                     return [symbol];
                 }
 
                 // Check if symbol is any of the alias
-                return findInMap(symbols, symbolFromSymbolTable => {
+                return forEachProperty(symbols, symbolFromSymbolTable => {
                     if (symbolFromSymbolTable.flags & SymbolFlags.Alias
                         && symbolFromSymbolTable.name !== "export="
                         && !getDeclarationOfKind(symbolFromSymbolTable, SyntaxKind.ExportSpecifier)) {
@@ -1771,7 +1763,7 @@ namespace ts {
             let qualify = false;
             forEachSymbolTableInScope(enclosingDeclaration, symbolTable => {
                 // If symbol of this name is not available in the symbol table we are ok
-                let symbolFromSymbolTable = symbolTable.get(symbol.name);
+                let symbolFromSymbolTable = symbolTable[symbol.name];
                 if (!symbolFromSymbolTable) {
                     // Continue to the next symbol table
                     return false;
@@ -2508,7 +2500,7 @@ namespace ts {
                     }
                     writeIndexSignature(resolved.stringIndexInfo, SyntaxKind.StringKeyword);
                     writeIndexSignature(resolved.numberIndexInfo, SyntaxKind.NumberKeyword);
-                    for (const p of sortInV8ObjectInsertionOrder(resolved.properties, p => p.name)) {
+                    for (const p of resolved.properties) {
                         const t = getTypeOfSymbol(p);
                         if (p.flags & (SymbolFlags.Function | SymbolFlags.Method) && !getPropertiesOfObjectType(t).length) {
                             const signatures = getSignaturesOfType(t, SignatureKind.Call);
@@ -3237,7 +3229,7 @@ namespace ts {
 
         // Return the type implied by an object binding pattern
         function getTypeFromObjectBindingPattern(pattern: ObjectBindingPattern, includePatternInType: boolean, reportErrors: boolean): Type {
-            const members = createMap<string, Symbol>();
+            const members = createMap<Symbol>();
             let hasComputedProperties = false;
             forEach(pattern.elements, e => {
                 const name = e.propertyName || <Identifier>e.name;
@@ -3252,7 +3244,7 @@ namespace ts {
                 const symbol = <TransientSymbol>createSymbol(flags, text);
                 symbol.type = getTypeFromBindingElement(e, includePatternInType, reportErrors);
                 symbol.bindingElement = e;
-                members.set(symbol.name, symbol);
+                members[symbol.name] = symbol;
             });
             const result = createAnonymousType(undefined, members, emptyArray, emptyArray, undefined, undefined);
             if (includePatternInType) {
@@ -3842,7 +3834,8 @@ namespace ts {
                     type.typeParameters = concatenate(outerTypeParameters, localTypeParameters);
                     type.outerTypeParameters = outerTypeParameters;
                     type.localTypeParameters = localTypeParameters;
-                    (<GenericType>type).instantiations = createMap([[getTypeListId(type.typeParameters), <GenericType>type]]);
+                    (<GenericType>type).instantiations = createMap<TypeReference>();
+                    (<GenericType>type).instantiations[getTypeListId(type.typeParameters)] = <GenericType>type;
                     (<GenericType>type).target = <GenericType>type;
                     (<GenericType>type).typeArguments = type.typeParameters;
                     type.thisType = <TypeParameter>createType(TypeFlags.TypeParameter);
@@ -3884,7 +3877,8 @@ namespace ts {
                     if (typeParameters) {
                         // Initialize the instantiation cache for generic type aliases. The declared type corresponds to
                         // an instantiation of the type alias with the type parameters supplied as type arguments.
-                        links.instantiations = createMap([[getTypeListId(links.typeParameters), type]]);
+                        links.instantiations = createMap<Type>();
+                        links.instantiations[getTypeListId(links.typeParameters)] = type;
                     }
                 }
                 else {
@@ -3904,7 +3898,7 @@ namespace ts {
             return expr.kind === SyntaxKind.NumericLiteral ||
                 expr.kind === SyntaxKind.PrefixUnaryExpression && (<PrefixUnaryExpression>expr).operator === SyntaxKind.MinusToken &&
                 (<PrefixUnaryExpression>expr).operand.kind === SyntaxKind.NumericLiteral ||
-                expr.kind === SyntaxKind.Identifier && !!symbol.exports.get((<Identifier>expr).text);
+                expr.kind === SyntaxKind.Identifier && !!symbol.exports[(<Identifier>expr).text];
         }
 
         function enumHasLiteralMembers(symbol: Symbol) {
@@ -3935,7 +3929,7 @@ namespace ts {
                 enumType.symbol = symbol;
                 if (enumHasLiteralMembers(symbol)) {
                     const memberTypeList: Type[] = [];
-                    const memberTypes: { [enumMemberValue: number]: EnumLiteralType } = [];
+                    const memberTypes = createMap<EnumLiteralType>();
                     for (const declaration of enumType.symbol.declarations) {
                         if (declaration.kind === SyntaxKind.EnumDeclaration) {
                             computeEnumMemberValues(<EnumDeclaration>declaration);
@@ -3943,7 +3937,8 @@ namespace ts {
                                 const memberSymbol = getSymbolOfNode(member);
                                 const value = getEnumMemberValue(member);
                                 if (!memberTypes[value]) {
-                                    memberTypeList.push(memberTypes[value] = createEnumLiteralType(memberSymbol, enumType, "" + value));
+                                    const memberType = memberTypes[value] = createEnumLiteralType(memberSymbol, enumType, "" + value);
+                                    memberTypeList.push(memberType);
                                 }
                             }
                         }
@@ -3952,7 +3947,7 @@ namespace ts {
                     if (memberTypeList.length > 1) {
                         enumType.flags |= TypeFlags.Union;
                         (<EnumType & UnionType>enumType).types = memberTypeList;
-                        unionTypes.set(getTypeListId(memberTypeList), <EnumType & UnionType>enumType);
+                        unionTypes[getTypeListId(memberTypeList)] = <EnumType & UnionType>enumType;
                     }
                 }
             }
@@ -4094,19 +4089,27 @@ namespace ts {
         }
 
         function createSymbolTable(symbols: Symbol[]): SymbolTable {
-            return arrayToMap(symbols, symbol => symbol.name);
+            const result = createMap<Symbol>();
+            for (const symbol of symbols) {
+                result[symbol.name] = symbol;
+            }
+            return result;
         }
 
         // The mappingThisOnly flag indicates that the only type parameter being mapped is "this". When the flag is true,
         // we check symbols to see if we can quickly conclude they are free of "this" references, thus needing no instantiation.
         function createInstantiatedSymbolTable(symbols: Symbol[], mapper: TypeMapper, mappingThisOnly: boolean): SymbolTable {
-            return arrayToMap(symbols, symbol => symbol.name, symbol => mappingThisOnly && isIndependentMember(symbol) ? symbol : instantiateSymbol(symbol, mapper));
+            const result = createMap<Symbol>();
+            for (const symbol of symbols) {
+                result[symbol.name] = mappingThisOnly && isIndependentMember(symbol) ? symbol : instantiateSymbol(symbol, mapper);
+            }
+            return result;
         }
 
         function addInheritedMembers(symbols: SymbolTable, baseSymbols: Symbol[]) {
             for (const s of baseSymbols) {
-                if (!symbols.get(s.name)) {
-                    symbols.set(s.name, s);
+                if (!symbols[s.name]) {
+                    symbols[s.name] = s;
                 }
             }
         }
@@ -4115,8 +4118,8 @@ namespace ts {
             if (!(<InterfaceTypeWithDeclaredMembers>type).declaredProperties) {
                 const symbol = type.symbol;
                 (<InterfaceTypeWithDeclaredMembers>type).declaredProperties = getNamedMembers(symbol.members);
-                (<InterfaceTypeWithDeclaredMembers>type).declaredCallSignatures = getSignaturesOfSymbol(symbol.members.get("__call"));
-                (<InterfaceTypeWithDeclaredMembers>type).declaredConstructSignatures = getSignaturesOfSymbol(symbol.members.get("__new"));
+                (<InterfaceTypeWithDeclaredMembers>type).declaredCallSignatures = getSignaturesOfSymbol(symbol.members["__call"]);
+                (<InterfaceTypeWithDeclaredMembers>type).declaredConstructSignatures = getSignaturesOfSymbol(symbol.members["__new"]);
                 (<InterfaceTypeWithDeclaredMembers>type).declaredStringIndexInfo = getIndexInfoOfSymbol(symbol, IndexKind.String);
                 (<InterfaceTypeWithDeclaredMembers>type).declaredNumberIndexInfo = getIndexInfoOfSymbol(symbol, IndexKind.Number);
             }
@@ -4356,8 +4359,8 @@ namespace ts {
             }
             else if (symbol.flags & SymbolFlags.TypeLiteral) {
                 const members = symbol.members;
-                const callSignatures = getSignaturesOfSymbol(members.get("__call"));
-                const constructSignatures = getSignaturesOfSymbol(members.get("__new"));
+                const callSignatures = getSignaturesOfSymbol(members["__call"]);
+                const constructSignatures = getSignaturesOfSymbol(members["__new"]);
                 const stringIndexInfo = getIndexInfoOfSymbol(symbol, IndexKind.String);
                 const numberIndexInfo = getIndexInfoOfSymbol(symbol, IndexKind.Number);
                 setStructuredTypeMembers(type, members, callSignatures, constructSignatures, stringIndexInfo, numberIndexInfo);
@@ -4371,7 +4374,7 @@ namespace ts {
                 }
                 if (symbol.flags & SymbolFlags.Class) {
                     const classType = getDeclaredTypeOfClassOrInterface(symbol);
-                    constructSignatures = getSignaturesOfSymbol(symbol.members.get("__constructor"));
+                    constructSignatures = getSignaturesOfSymbol(symbol.members["__constructor"]);
                     if (!constructSignatures.length) {
                         constructSignatures = getDefaultConstructSignatures(classType);
                     }
@@ -4429,7 +4432,7 @@ namespace ts {
         function getPropertyOfObjectType(type: Type, name: string): Symbol {
             if (type.flags & TypeFlags.Object) {
                 const resolved = resolveStructuredTypeMembers(<ObjectType>type);
-                const symbol = resolved.members.get(name);
+                const symbol = resolved.members[name];
                 if (symbol && symbolIsValue(symbol)) {
                     return symbol;
                 }
@@ -4450,12 +4453,13 @@ namespace ts {
             const props = type.resolvedProperties;
             if (props) {
                 const result: Symbol[] = [];
-                props.forEach(prop =>  {
+                for (const key in props) {
+                    const prop = props[key];
                     // We need to filter out partial properties in union types
                     if (!(prop.flags & SymbolFlags.SyntheticProperty && (<TransientSymbol>prop).isPartial)) {
                         result.push(prop);
                     }
-                });
+                }
                 return result;
             }
             return emptyArray;
@@ -4572,12 +4576,12 @@ namespace ts {
         // these partial properties when identifying discriminant properties, but otherwise they are filtered out
         // and do not appear to be present in the union type.
         function getUnionOrIntersectionProperty(type: UnionOrIntersectionType, name: string): Symbol {
-            const properties = type.resolvedProperties || (type.resolvedProperties = createMap<string, Symbol>());
-            let property = properties.get(name);
+            const properties = type.resolvedProperties || (type.resolvedProperties = createMap<Symbol>());
+            let property = properties[name];
             if (!property) {
                 property = createUnionOrIntersectionProperty(type, name);
                 if (property) {
-                    properties.set(name, property);
+                    properties[name] = property;
                 }
             }
             return property;
@@ -4601,7 +4605,7 @@ namespace ts {
             type = getApparentType(type);
             if (type.flags & TypeFlags.Object) {
                 const resolved = resolveStructuredTypeMembers(<ObjectType>type);
-                const symbol = resolved.members.get(name);
+                const symbol = resolved.members[name];
                 if (symbol && symbolIsValue(symbol)) {
                     return symbol;
                 }
@@ -4700,11 +4704,11 @@ namespace ts {
 
         function symbolsToArray(symbols: SymbolTable): Symbol[] {
             const result: Symbol[] = [];
-            symbols.forEach((symbol, id) => {
+            for (const id in symbols) {
                 if (!isReservedMemberName(id)) {
-                    result.push(symbol);
+                    result.push(symbols[id]);
                 }
-            });
+            }
             return result;
         }
 
@@ -4996,7 +5000,7 @@ namespace ts {
         }
 
         function getIndexSymbol(symbol: Symbol): Symbol {
-            return symbol.members.get("__index");
+            return symbol.members["__index"];
         }
 
         function getIndexDeclarationOfSymbol(symbol: Symbol, kind: IndexKind): SignatureDeclaration {
@@ -5110,9 +5114,9 @@ namespace ts {
 
         function createTypeReference(target: GenericType, typeArguments: Type[]): TypeReference {
             const id = getTypeListId(typeArguments);
-            let type = target.instantiations.get(id);
+            let type = target.instantiations[id];
             if (!type) {
-                type = setAndReturn(target.instantiations, id, <TypeReference>createObjectType(ObjectFlags.Reference, target.symbol));
+                type = target.instantiations[id] = <TypeReference>createObjectType(ObjectFlags.Reference, target.symbol);
                 type.flags |= typeArguments ? getPropagatingFlagsOfTypes(typeArguments, /*excludeKinds*/ 0) : 0;
                 type.target = target;
                 type.typeArguments = typeArguments;
@@ -5168,7 +5172,7 @@ namespace ts {
                 }
                 const typeArguments = map(node.typeArguments, getTypeFromTypeNodeNoAlias);
                 const id = getTypeListId(typeArguments);
-                return links.instantiations.get(id) || setAndReturn(links.instantiations, id, instantiateType(type, createTypeMapper(typeParameters, typeArguments)));
+                return links.instantiations[id] || (links.instantiations[id] = instantiateType(type, createTypeMapper(typeParameters, typeArguments)));
             }
             if (node.typeArguments) {
                 error(node, Diagnostics.Type_0_is_not_generic, symbolToString(symbol));
@@ -5393,7 +5397,8 @@ namespace ts {
             type.typeParameters = typeParameters;
             type.outerTypeParameters = undefined;
             type.localTypeParameters = typeParameters;
-            type.instantiations = createMap([[getTypeListId(type.typeParameters), <GenericType>type]]);
+            type.instantiations = createMap<TypeReference>();
+            type.instantiations[getTypeListId(type.typeParameters)] = <GenericType>type;
             type.target = <GenericType>type;
             type.typeArguments = type.typeParameters;
             type.thisType = <TypeParameter>createType(TypeFlags.TypeParameter);
@@ -5597,10 +5602,10 @@ namespace ts {
                 return types[0];
             }
             const id = getTypeListId(types);
-            let type = unionTypes.get(id);
+            let type = unionTypes[id];
             if (!type) {
                 const propagatedFlags = getPropagatingFlagsOfTypes(types, /*excludeKinds*/ TypeFlags.Nullable);
-                type = setAndReturn(unionTypes, id, <UnionType>createType(TypeFlags.Union | propagatedFlags));
+                type = unionTypes[id] = <UnionType>createType(TypeFlags.Union | propagatedFlags);
                 type.types = types;
                 type.aliasSymbol = aliasSymbol;
                 type.aliasTypeArguments = aliasTypeArguments;
@@ -5668,10 +5673,10 @@ namespace ts {
                 return typeSet[0];
             }
             const id = getTypeListId(typeSet);
-            let type = intersectionTypes.get(id);
+            let type = intersectionTypes[id];
             if (!type) {
                 const propagatedFlags = getPropagatingFlagsOfTypes(typeSet, /*excludeKinds*/ TypeFlags.Nullable);
-                type = setAndReturn(intersectionTypes, id, <IntersectionType>createType(TypeFlags.Intersection | propagatedFlags));
+                type = intersectionTypes[id] = <IntersectionType>createType(TypeFlags.Intersection | propagatedFlags);
                 type.types = typeSet;
                 type.aliasSymbol = aliasSymbol;
                 type.aliasTypeArguments = aliasTypeArguments;
@@ -5723,7 +5728,7 @@ namespace ts {
 
         function getLiteralTypeForText(flags: TypeFlags, text: string) {
             const map = flags & TypeFlags.StringLiteral ? stringLiteralTypes : numericLiteralTypes;
-            return map.get(text) || setAndReturn(map, text, createLiteralType(flags, text));
+            return map[text] || (map[text] = createLiteralType(flags, text));
         }
 
         function getTypeFromLiteralTypeNode(node: LiteralTypeNode): Type {
@@ -6419,14 +6424,13 @@ namespace ts {
                 return true;
             }
             const id = source.id + "," + target.id;
-            const relation = enumRelation.get(id);
-            if (relation !== undefined) {
-                return relation;
+            if (enumRelation[id] !== undefined) {
+                return enumRelation[id];
             }
             if (source.symbol.name !== target.symbol.name ||
                 !(source.symbol.flags & SymbolFlags.RegularEnum) || !(target.symbol.flags & SymbolFlags.RegularEnum) ||
                 (source.flags & TypeFlags.Union) !== (target.flags & TypeFlags.Union)) {
-                return setAndReturn(enumRelation, id, false);
+                return enumRelation[id] = false;
             }
             const targetEnumType = getTypeOfSymbol(target.symbol);
             for (const property of getPropertiesOfType(getTypeOfSymbol(source.symbol))) {
@@ -6437,14 +6441,14 @@ namespace ts {
                             errorReporter(Diagnostics.Property_0_is_missing_in_type_1, property.name,
                                 typeToString(target, /*enclosingDeclaration*/ undefined, TypeFormatFlags.UseFullyQualifiedType));
                         }
-                        return setAndReturn(enumRelation, id, false);
+                        return enumRelation[id] = false;
                     }
                 }
             }
-            return setAndReturn(enumRelation, id, true);
+            return enumRelation[id] = true;
         }
 
-        function isSimpleTypeRelatedTo(source: Type, target: Type, relation: Map<string, RelationComparisonResult>, errorReporter?: ErrorReporter) {
+        function isSimpleTypeRelatedTo(source: Type, target: Type, relation: Map<RelationComparisonResult>, errorReporter?: ErrorReporter) {
             if (target.flags & TypeFlags.Never) return false;
             if (target.flags & TypeFlags.Any || source.flags & TypeFlags.Never) return true;
             if (source.flags & TypeFlags.StringLike && target.flags & TypeFlags.String) return true;
@@ -6472,7 +6476,7 @@ namespace ts {
             return false;
         }
 
-        function isTypeRelatedTo(source: Type, target: Type, relation: Map<string, RelationComparisonResult>) {
+        function isTypeRelatedTo(source: Type, target: Type, relation: Map<RelationComparisonResult>) {
             if (source.flags & TypeFlags.StringOrNumberLiteral && source.flags & TypeFlags.FreshLiteral) {
                 source = (<LiteralType>source).regularType;
             }
@@ -6484,7 +6488,7 @@ namespace ts {
             }
             if (source.flags & TypeFlags.Object && target.flags & TypeFlags.Object) {
                 const id = relation !== identityRelation || source.id < target.id ? source.id + "," + target.id : target.id + "," + source.id;
-                const related = relation.get(id);
+                const related = relation[id];
                 if (related !== undefined) {
                     return related === RelationComparisonResult.Succeeded;
                 }
@@ -6508,7 +6512,7 @@ namespace ts {
         function checkTypeRelatedTo(
             source: Type,
             target: Type,
-            relation: Map<string, RelationComparisonResult>,
+            relation: Map<RelationComparisonResult>,
             errorNode: Node,
             headMessage?: DiagnosticMessage,
             containingMessageChain?: DiagnosticMessageChain): boolean {
@@ -6516,7 +6520,7 @@ namespace ts {
             let errorInfo: DiagnosticMessageChain;
             let sourceStack: Type[];
             let targetStack: Type[];
-            let maybeStack: Map<string, RelationComparisonResult>[];
+            let maybeStack: Map<RelationComparisonResult>[];
             let expandingFlags: number;
             let depth = 0;
             let overflow = false;
@@ -6875,12 +6879,12 @@ namespace ts {
                     return Ternary.False;
                 }
                 const id = relation !== identityRelation || source.id < target.id ? source.id + "," + target.id : target.id + "," + source.id;
-                const related = relation.get(id);
+                const related = relation[id];
                 if (related !== undefined) {
                     if (reportErrors && related === RelationComparisonResult.Failed) {
                         // We are elaborating errors and the cached result is an unreported failure. Record the result as a reported
                         // failure and continue computing the relation such that errors get reported.
-                        relation.set(id, RelationComparisonResult.FailedAndReported);
+                        relation[id] = RelationComparisonResult.FailedAndReported;
                     }
                     else {
                         return related === RelationComparisonResult.Succeeded ? Ternary.True : Ternary.False;
@@ -6889,7 +6893,7 @@ namespace ts {
                 if (depth > 0) {
                     for (let i = 0; i < depth; i++) {
                         // If source and target are already being compared, consider them related with assumptions
-                        if (maybeStack[i].get(id)) {
+                        if (maybeStack[i][id]) {
                             return Ternary.Maybe;
                         }
                     }
@@ -6906,7 +6910,8 @@ namespace ts {
                 }
                 sourceStack[depth] = source;
                 targetStack[depth] = target;
-                maybeStack[depth] = createMap([[id, RelationComparisonResult.Succeeded]]);
+                maybeStack[depth] = createMap<RelationComparisonResult>();
+                maybeStack[depth][id] = RelationComparisonResult.Succeeded;
                 depth++;
                 const saveExpandingFlags = expandingFlags;
                 if (!(expandingFlags & 1) && isDeeplyNestedGeneric(source, sourceStack, depth)) expandingFlags |= 1;
@@ -6936,12 +6941,12 @@ namespace ts {
                     const maybeCache = maybeStack[depth];
                     // If result is definitely true, copy assumptions to global cache, else copy to next level up
                     const destinationCache = (result === Ternary.True || depth === 0) ? relation : maybeStack[depth - 1];
-                    copyMapEntriesFromTo(maybeCache, destinationCache);
+                    copyProperties(maybeCache, destinationCache);
                 }
                 else {
                     // A false result goes straight into global cache (when something is false under assumptions it
                     // will also be false without assumptions)
-                    relation.set(id, reportErrors ? RelationComparisonResult.FailedAndReported : RelationComparisonResult.Failed);
+                    relation[id] = reportErrors ? RelationComparisonResult.FailedAndReported : RelationComparisonResult.Failed;
                 }
                 return result;
             }
@@ -7130,29 +7135,14 @@ namespace ts {
                 return result;
             }
 
-            /**
-             * For consistency we report the first error in V8 object insertion order.
-             * Since that's slow and there usually isn't an error, we only sort properties the second time around.
-             */
-            function eachPropertyRelatedTo(source: Type, target: Type, kind: IndexKind, reportErrors: boolean, redoingInV8ObjectInsertionOrder?: boolean): Ternary {
+            function eachPropertyRelatedTo(source: Type, target: Type, kind: IndexKind, reportErrors: boolean): Ternary {
                 let result = Ternary.True;
-                let properties = getPropertiesOfObjectType(source);
-                if (redoingInV8ObjectInsertionOrder) {
-                    properties = sortInV8ObjectInsertionOrder(properties, prop => prop.name);
-                }
-                for (const prop of properties) {
+                for (const prop of getPropertiesOfObjectType(source)) {
                     if (kind === IndexKind.String || isNumericLiteralName(prop.name)) {
-                        const related = isRelatedTo(getTypeOfSymbol(prop), target, reportErrors && redoingInV8ObjectInsertionOrder);
+                        const related = isRelatedTo(getTypeOfSymbol(prop), target, reportErrors);
                         if (!related) {
                             if (reportErrors) {
-                                // For consistency, if we report errors we make sure to report the first error in V8's object insertion order.
-                                if (!redoingInV8ObjectInsertionOrder) {
-                                    const related = eachPropertyRelatedTo(source,  target, kind, reportErrors, /*redoingInV8ObjectInsertionOrder*/ true);
-                                    Debug.assert(related === Ternary.False);
-                                }
-                                else {
-                                    reportError(Diagnostics.Property_0_is_incompatible_with_index_signature, symbolToString(prop));
-                                }
+                                reportError(Diagnostics.Property_0_is_incompatible_with_index_signature, symbolToString(prop));
                             }
                             return Ternary.False;
                         }
@@ -7591,11 +7581,11 @@ namespace ts {
         }
 
         function transformTypeOfMembers(type: Type, f: (propertyType: Type) => Type) {
-            const members = createMap<string, Symbol>();
+            const members = createMap<Symbol>();
             for (const property of getPropertiesOfObjectType(type)) {
                 const original = getTypeOfSymbol(property);
                 const updated = f(original);
-                members.set(property.name, updated === original ? property : createTransientSymbol(property, updated));
+                members[property.name] = updated === original ? property : createTransientSymbol(property, updated);
             };
             return members;
         }
@@ -7814,7 +7804,7 @@ namespace ts {
             let targetStack: Type[];
             let depth = 0;
             let inferiority = 0;
-            const visited = createSet();
+            const visited = createMap<boolean>();
             inferFromTypes(originalSource, originalTarget);
 
             function isInProcess(source: Type, target: Type) {
@@ -7950,10 +7940,10 @@ namespace ts {
                             return;
                         }
                         const key = source.id + "," + target.id;
-                        if (visited.has(key)) {
+                        if (visited[key]) {
                             return;
                         }
-                        visited.add(key);
+                        visited[key] = true;
                         if (depth === 0) {
                             sourceStack = [];
                             targetStack = [];
@@ -8304,7 +8294,7 @@ namespace ts {
             // check. This gives us a quicker out in the common case where an object type is not a function.
             const resolved = resolveStructuredTypeMembers(type);
             return !!(resolved.callSignatures.length || resolved.constructSignatures.length ||
-                resolved.members.get("bind") && isTypeSubtypeOf(type, globalFunctionType));
+                resolved.members["bind"] && isTypeSubtypeOf(type, globalFunctionType));
         }
 
         function getTypeFacts(type: Type): TypeFacts {
@@ -8894,13 +8884,12 @@ namespace ts {
                 // If we have previously computed the control flow type for the reference at
                 // this flow loop junction, return the cached type.
                 const id = getFlowNodeId(flow);
-                const cache = flowLoopCaches[id] || (flowLoopCaches[id] = createMap<string, Type>());
+                const cache = flowLoopCaches[id] || (flowLoopCaches[id] = createMap<Type>());
                 if (!key) {
                     key = getFlowCacheKey(reference);
                 }
-                const cached = cache.get(key);
-                if (cached) {
-                    return cached;
+                if (cache[key]) {
+                    return cache[key];
                 }
                 // If this flow loop junction and reference are already being processed, return
                 // the union of the types computed for each branch so far, marked as incomplete.
@@ -8934,9 +8923,8 @@ namespace ts {
                     // If we see a value appear in the cache it is a sign that control flow  analysis
                     // was restarted and completed by checkExpressionCached. We can simply pick up
                     // the resulting type and bail out.
-                    const cached = cache.get(key);
-                    if (cached) {
-                        return cached;
+                    if (cache[key]) {
+                        return cache[key];
                     }
                     if (!contains(antecedentTypes, type)) {
                         antecedentTypes.push(type);
@@ -8960,7 +8948,7 @@ namespace ts {
                 if (isIncomplete(firstAntecedentType)) {
                     return createFlowType(result, /*incomplete*/ true);
                 }
-                return setAndReturn(cache, key, result);
+                return cache[key] = result;
             }
 
             function isMatchingReferenceDiscriminant(expr: Expression) {
@@ -9083,14 +9071,14 @@ namespace ts {
                     // We narrow a non-union type to an exact primitive type if the non-union type
                     // is a supertype of that primitive type. For example, type 'any' can be narrowed
                     // to one of the primitive types.
-                    const targetType = typeofTypesByName.get(literal.text);
+                    const targetType = typeofTypesByName[literal.text];
                     if (targetType && isTypeSubtypeOf(targetType, type)) {
                         return targetType;
                     }
                 }
                 const facts = assumeTrue ?
-                    typeofEQFacts.get(literal.text) || TypeFacts.TypeofEQHostObject :
-                    typeofNEFacts.get(literal.text) || TypeFacts.TypeofNEHostObject;
+                    typeofEQFacts[literal.text] || TypeFacts.TypeofEQHostObject :
+                    typeofNEFacts[literal.text] || TypeFacts.TypeofNEHostObject;
                 return getTypeWithFacts(type, facts);
             }
 
@@ -10594,7 +10582,7 @@ namespace ts {
             // Grammar checking
             checkGrammarObjectLiteralExpression(node, inDestructuringPattern);
 
-            const propertiesTable = createMap<string, Symbol>();
+            const propertiesTable = createMap<Symbol>();
             const propertiesArray: Symbol[] = [];
             const contextualType = getApparentTypeOfContextualType(node);
             const contextualTypeHasPattern = contextualType && contextualType.pattern &&
@@ -10676,7 +10664,7 @@ namespace ts {
                     }
                 }
                 else {
-                    propertiesTable.set(member.name, member);
+                    propertiesTable[member.name] = member;
                 }
                 propertiesArray.push(member);
             }
@@ -10685,12 +10673,12 @@ namespace ts {
             // type with those properties for which the binding pattern specifies a default value.
             if (contextualTypeHasPattern) {
                 for (const prop of getPropertiesOfType(contextualType)) {
-                    if (!propertiesTable.get(prop.name)) {
+                    if (!propertiesTable[prop.name]) {
                         if (!(prop.flags & SymbolFlags.Optional)) {
                             error(prop.valueDeclaration || (<TransientSymbol>prop).bindingElement,
                                 Diagnostics.Initializer_provides_no_value_for_this_binding_element_and_the_binding_element_has_no_default_value);
                         }
-                        propertiesTable.set(prop.name, prop);
+                        propertiesTable[prop.name] = prop;
                         propertiesArray.push(prop);
                     }
                 }
@@ -10767,7 +10755,7 @@ namespace ts {
             }
         }
 
-        function checkJsxAttribute(node: JsxAttribute, elementAttributesType: Type, nameTable: Set<string>) {
+        function checkJsxAttribute(node: JsxAttribute, elementAttributesType: Type, nameTable: Map<boolean>) {
             let correspondingPropType: Type = undefined;
 
             // Look up the corresponding property for this attribute
@@ -10806,35 +10794,34 @@ namespace ts {
                 checkTypeAssignableTo(exprType, correspondingPropType, node);
             }
 
-            nameTable.add(node.name.text);
+            nameTable[node.name.text] = true;
             return exprType;
         }
 
-        function checkJsxSpreadAttribute(node: JsxSpreadAttribute, elementAttributesType: Type, nameTable: Set<string>) {
+        function checkJsxSpreadAttribute(node: JsxSpreadAttribute, elementAttributesType: Type, nameTable: Map<boolean>) {
             const type = checkExpression(node.expression);
             const props = getPropertiesOfType(type);
             for (const prop of props) {
                 // Is there a corresponding property in the element attributes type? Skip checking of properties
                 // that have already been assigned to, as these are not actually pushed into the resulting type
-                if (!nameTable.has(prop.name)) {
+                if (!nameTable[prop.name]) {
                     const targetPropSym = getPropertyOfType(elementAttributesType, prop.name);
                     if (targetPropSym) {
                         const msg = chainDiagnosticMessages(undefined, Diagnostics.Property_0_of_JSX_spread_attribute_is_not_assignable_to_target_property, prop.name);
                         checkTypeAssignableTo(getTypeOfSymbol(prop), getTypeOfSymbol(targetPropSym), node, undefined, msg);
                     }
 
-                    nameTable.add(prop.name);
+                    nameTable[prop.name] = true;
                 }
             }
             return type;
         }
 
         function getJsxType(name: string) {
-            const jsxType = jsxTypes.get(name);
-            if (jsxType === undefined) {
-                return setAndReturn(jsxTypes, name, getExportedTypeFromNamespace(JsxNames.JSX, name) || unknownType);
+            if (jsxTypes[name] === undefined) {
+                return jsxTypes[name] = getExportedTypeFromNamespace(JsxNames.JSX, name) || unknownType;
             }
-            return jsxType;
+            return jsxTypes[name];
         }
 
         /**
@@ -11145,7 +11132,7 @@ namespace ts {
 
             const targetAttributesType = getJsxElementAttributesType(node);
 
-            const nameTable = createSet();
+            const nameTable = createMap<boolean>();
             // Process this array in right-to-left order so we know which
             // attributes (mostly from spreads) are being overwritten and
             // thus should have their types ignored
@@ -11169,7 +11156,7 @@ namespace ts {
                 const targetProperties = getPropertiesOfType(targetAttributesType);
                 for (let i = 0; i < targetProperties.length; i++) {
                     if (!(targetProperties[i].flags & SymbolFlags.Optional) &&
-                        !nameTable.has(targetProperties[i].name)) {
+                        !nameTable[targetProperties[i].name]) {
 
                         error(node, Diagnostics.Property_0_is_missing_in_type_1, targetProperties[i].name, typeToString(targetAttributesType));
                     }
@@ -11899,7 +11886,7 @@ namespace ts {
             return typeArgumentsAreAssignable;
         }
 
-        function checkApplicableSignature(node: CallLikeExpression, args: Expression[], signature: Signature, relation: Map<string, RelationComparisonResult>, excludeArgument: boolean[], reportErrors: boolean) {
+        function checkApplicableSignature(node: CallLikeExpression, args: Expression[], signature: Signature, relation: Map<RelationComparisonResult>, excludeArgument: boolean[], reportErrors: boolean) {
             const thisType = getThisTypeOfSignature(signature);
             if (thisType && thisType !== voidType && node.kind !== SyntaxKind.NewExpression) {
                 // If the called expression is not of the form `x.f` or `x["f"]`, then sourceType = voidType
@@ -12433,7 +12420,7 @@ namespace ts {
                 diagnostics.add(createDiagnosticForNodeFromMessageChain(node, errorInfo));
             }
 
-            function chooseOverload(candidates: Signature[], relation: Map<string, RelationComparisonResult>, signatureHelpTrailingComma = false) {
+            function chooseOverload(candidates: Signature[], relation: Map<RelationComparisonResult>, signatureHelpTrailingComma = false) {
                 for (const originalCandidate of candidates) {
                     if (!hasCorrectArity(node, args, originalCandidate, signatureHelpTrailingComma)) {
                         continue;
@@ -14622,8 +14609,8 @@ namespace ts {
                 Property = Getter | Setter
             }
 
-            const instanceNames = createMap<string, Accessor>();
-            const staticNames = createMap<string, Accessor>();
+            const instanceNames = createMap<Accessor>();
+            const staticNames = createMap<Accessor>();
             for (const member of node.members) {
                 if (member.kind === SyntaxKind.Constructor) {
                     for (const param of (member as ConstructorDeclaration).parameters) {
@@ -14655,24 +14642,24 @@ namespace ts {
                 }
             }
 
-            function addName(names: Map<string, Accessor>, location: Node, name: string, meaning: Accessor) {
-                const prev = names.get(name);
+            function addName(names: Map<Accessor>, location: Node, name: string, meaning: Accessor) {
+                const prev = names[name];
                 if (prev) {
                     if (prev & meaning) {
                         error(location, Diagnostics.Duplicate_identifier_0, getTextOfNode(location));
                     }
                     else {
-                        names.set(name, prev | meaning);
+                        names[name] = prev | meaning;
                     }
                 }
                 else {
-                    names.set(name, meaning);
+                    names[name] = meaning;
                 }
             }
         }
 
         function checkObjectTypeForDuplicateDeclarations(node: TypeLiteralNode | InterfaceDeclaration) {
-            const names = createSet();
+            const names = createMap<boolean>();
             for (const member of node.members) {
                 if (member.kind == SyntaxKind.PropertySignature) {
                     let memberName: string;
@@ -14686,12 +14673,12 @@ namespace ts {
                             continue;
                     }
 
-                    if (names.has(memberName)) {
+                    if (names[memberName]) {
                         error(member.symbol.valueDeclaration.name, Diagnostics.Duplicate_identifier_0, memberName);
                         error(member.name, Diagnostics.Duplicate_identifier_0, memberName);
                     }
                     else {
-                        names.add(memberName);
+                        names[memberName] = true;
                     }
                 }
             }
@@ -15896,7 +15883,8 @@ namespace ts {
 
         function checkUnusedLocalsAndParameters(node: Node): void {
             if (node.parent.kind !== SyntaxKind.InterfaceDeclaration && noUnusedIdentifiers && !isInAmbientContext(node)) {
-                node.locals.forEach(local => {
+                for (const key in node.locals) {
+                    const local = node.locals[key];
                     if (!local.isReferenced) {
                         if (local.valueDeclaration && getRootDeclaration(local.valueDeclaration).kind === SyntaxKind.Parameter) {
                             const parameter = <ParameterDeclaration>getRootDeclaration(local.valueDeclaration);
@@ -15911,7 +15899,7 @@ namespace ts {
                             forEach(local.declarations, d => errorUnusedLocal(d.name || d, local.name));
                         }
                     }
-                });
+                }
             }
         }
 
@@ -15977,7 +15965,8 @@ namespace ts {
 
         function checkUnusedModuleMembers(node: ModuleDeclaration | SourceFile): void {
             if (compilerOptions.noUnusedLocals && !isInAmbientContext(node)) {
-                node.locals.forEach(local => {
+                for (const key in node.locals) {
+                    const local = node.locals[key];
                     if (!local.isReferenced && !local.exportSymbol) {
                         for (const declaration of local.declarations) {
                             if (!isAmbientModule(declaration)) {
@@ -15985,7 +15974,7 @@ namespace ts {
                             }
                         }
                     }
-                });
+                }
             }
         }
 
@@ -17002,12 +16991,12 @@ namespace ts {
                     else {
                         const blockLocals = catchClause.block.locals;
                         if (blockLocals) {
-                            forEachKeyInMap(catchClause.locals, caughtName => {
-                                const blockLocal = blockLocals.get(caughtName);
+                            for (const caughtName in catchClause.locals) {
+                                const blockLocal = blockLocals[caughtName];
                                 if (blockLocal && (blockLocal.flags & SymbolFlags.BlockScopedVariable) !== 0) {
                                     grammarErrorOnNode(blockLocal.valueDeclaration, Diagnostics.Cannot_redeclare_identifier_0_in_catch_clause, caughtName);
                                 }
-                            });
+                            }
                         }
                     }
                 }
@@ -17426,15 +17415,16 @@ namespace ts {
                 return true;
             }
 
-            const seen: Map<string, { prop: Symbol; containingType: Type }> = arrayToMap(resolveDeclaredMembers(type).declaredProperties, p => p.name, p => ({ prop: p, containingType: type }));
+            const seen = createMap<{ prop: Symbol; containingType: Type }>();
+            forEach(resolveDeclaredMembers(type).declaredProperties, p => { seen[p.name] = { prop: p, containingType: type }; });
             let ok = true;
 
             for (const base of baseTypes) {
                 const properties = getPropertiesOfObjectType(getTypeWithThisArgument(base, type.thisType));
                 for (const prop of properties) {
-                    const existing = seen.get(prop.name);
+                    const existing = seen[prop.name];
                     if (!existing) {
-                        seen.set(prop.name, { prop, containingType: base });
+                        seen[prop.name] = { prop: prop, containingType: base };
                     }
                     else {
                         const isInheritedProperty = existing.containingType !== type;
@@ -18176,14 +18166,19 @@ namespace ts {
         }
 
         function hasExportedMembers(moduleSymbol: Symbol) {
-            return someKeyInMap(moduleSymbol.exports, id => id !== "export=");
+            for (const id in moduleSymbol.exports) {
+                if (id !== "export=") {
+                    return true;
+                }
+            }
+            return false;
         }
 
         function checkExternalModuleExports(node: SourceFile | ModuleDeclaration) {
             const moduleSymbol = getSymbolOfNode(node);
             const links = getSymbolLinks(moduleSymbol);
             if (!links.exportsChecked) {
-                const exportEqualsSymbol = moduleSymbol.exports.get("export=");
+                const exportEqualsSymbol = moduleSymbol.exports["export="];
                 if (exportEqualsSymbol && hasExportedMembers(moduleSymbol)) {
                     const declaration = getDeclarationOfAliasSymbol(exportEqualsSymbol) || exportEqualsSymbol.valueDeclaration;
                     if (!isTopLevelInExternalModuleAugmentation(declaration)) {
@@ -18192,20 +18187,21 @@ namespace ts {
                 }
                 // Checks for export * conflicts
                 const exports = getExportsOfModule(moduleSymbol);
-                exports && exports.forEach(({ declarations, flags }, id) => {
+                for (const id in exports) {
                     if (id === "__export") {
-                        return;
+                        continue;
                     }
+                    const { declarations, flags } = exports[id];
                     // ECMA262: 15.2.1.1 It is a Syntax Error if the ExportedNames of ModuleItemList contains any duplicate entries.
                     // (TS Exceptions: namespaces, function overloads, enums, and interfaces)
                     if (flags & (SymbolFlags.Namespace | SymbolFlags.Interface | SymbolFlags.Enum)) {
-                        return;
+                        continue;
                     }
                     const exportedDeclarationsCount = countWhere(declarations, isNotOverload);
                     if (flags & SymbolFlags.TypeAlias && exportedDeclarationsCount <= 2) {
                         // it is legal to merge type alias with other values
                         // so count should be either 1 (just type alias) or 2 (type alias + merged value)
-                        return;
+                        continue;
                     }
                     if (exportedDeclarationsCount > 1) {
                         for (const declaration of declarations) {
@@ -18214,7 +18210,7 @@ namespace ts {
                             }
                         }
                     }
-                });
+                }
                 links.exportsChecked = true;
             }
 
@@ -18490,7 +18486,7 @@ namespace ts {
         }
 
         function getSymbolsInScope(location: Node, meaning: SymbolFlags): Symbol[] {
-            const symbols = createMap<string, Symbol>();
+            const symbols = createMap<Symbol>();
             let memberFlags: ModifierFlags = ModifierFlags.None;
 
             if (isInsideWithStatementBody(location)) {
@@ -18568,17 +18564,18 @@ namespace ts {
                     // We will copy all symbol regardless of its reserved name because
                     // symbolsToArray will check whether the key is a reserved name and
                     // it will not copy symbol with reserved name to the array
-                    if (!symbols.get(id)) {
-                        symbols.set(id, symbol);
+                    if (!symbols[id]) {
+                        symbols[id] = symbol;
                     }
                 }
             }
 
             function copySymbols(source: SymbolTable, meaning: SymbolFlags): void {
                 if (meaning) {
-                    source.forEach(symbol => {
+                    for (const id in source) {
+                        const symbol = source[id];
                         copySymbol(symbol, meaning);
-                    });
+                    }
                 }
             }
         }
@@ -18989,8 +18986,8 @@ namespace ts {
             const propsByName = createSymbolTable(getPropertiesOfType(type));
             if (getSignaturesOfType(type, SignatureKind.Call).length || getSignaturesOfType(type, SignatureKind.Construct).length) {
                 forEach(getPropertiesOfType(globalFunctionType), p => {
-                    if (!propsByName.get(p.name)) {
-                        propsByName.set(p.name, p);
+                    if (!propsByName[p.name]) {
+                        propsByName[p.name] = p;
                     }
                 });
             }
@@ -19053,7 +19050,7 @@ namespace ts {
                 // otherwise - check if at least one export is value
                 symbolLinks.exportsSomeValue = hasExportAssignment
                     ? !!(moduleSymbol.flags & SymbolFlags.Value)
-                    : someValueInMap(getExportsOfModule(moduleSymbol), isValue);
+                    : forEachProperty(getExportsOfModule(moduleSymbol), isValue);
             }
 
             return symbolLinks.exportsSomeValue;
@@ -19403,7 +19400,7 @@ namespace ts {
         }
 
         function hasGlobalName(name: string): boolean {
-            return !!globals.get(name);
+            return !!globals[name];
         }
 
         function getReferencedValueSymbol(reference: Identifier, startInDeclarationContainer?: boolean): Symbol {
@@ -19460,13 +19457,14 @@ namespace ts {
             if (resolvedTypeReferenceDirectives) {
                 // populate reverse mapping: file path -> type reference directive that was resolved to this file
                 fileToDirective = createFileMap<string>();
-                resolvedTypeReferenceDirectives.forEach((resolvedDirective, key) => {
+                for (const key in resolvedTypeReferenceDirectives) {
+                    const resolvedDirective = resolvedTypeReferenceDirectives[key];
                     if (!resolvedDirective) {
-                        return;
+                        continue;
                     }
                     const file = host.getSourceFile(resolvedDirective.resolvedFileName);
                     fileToDirective.set(file.path, key);
-                });
+                }
             }
             return {
                 getReferencedExportContainer,
@@ -19590,8 +19588,6 @@ namespace ts {
 
         function initializeTypeChecker() {
             // Bind all source files and propagate errors
-            performance.mark("heapBeforeBind");
-
             for (const file of host.getSourceFiles()) {
                 bindSourceFile(file, compilerOptions);
             }
@@ -19613,9 +19609,11 @@ namespace ts {
                 if (file.symbol && file.symbol.globalExports) {
                     // Merge in UMD exports with first-in-wins semantics (see #9771)
                     const source = file.symbol.globalExports;
-                    source.forEach((sourceSymbol, id) => {
-                        setIfNotSet(globals, id, sourceSymbol);
-                    });
+                    for (const id in source) {
+                        if (!(id in globals)) {
+                            globals[id] = source[id];
+                        }
+                    }
                 }
                 if ((compilerOptions.isolatedModules || isExternalModule(file)) && !file.isDeclarationFile) {
                     const fileRequestedExternalEmitHelpers = file.flags & NodeFlags.EmitHelperFlags;
@@ -19641,8 +19639,6 @@ namespace ts {
             // Setup global builtins
             addToSymbolTable(globals, builtinGlobals, Diagnostics.Declaration_name_conflicts_with_built_in_global_identifier_0);
 
-            performance.mark("heapAfterBind");
-
             getSymbolLinks(undefinedSymbol).type = undefinedWideningType;
             getSymbolLinks(argumentsSymbol).type = getGlobalType("IArguments");
             getSymbolLinks(unknownSymbol).type = unknownType;
@@ -20315,7 +20311,7 @@ namespace ts {
         }
 
         function checkGrammarObjectLiteralExpression(node: ObjectLiteralExpression, inDestructuring: boolean) {
-            const seen = createMap<string, SymbolFlags>();
+            const seen = createMap<SymbolFlags>();
             const Property = 1;
             const GetAccessor = 2;
             const SetAccessor = 4;
@@ -20378,17 +20374,17 @@ namespace ts {
                     continue;
                 }
 
-                const existingKind = seen.get(effectiveName);
-                if (!existingKind) {
-                    seen.set(effectiveName, currentKind);
+                if (!seen[effectiveName]) {
+                    seen[effectiveName] = currentKind;
                 }
                 else {
+                    const existingKind = seen[effectiveName];
                     if (currentKind === Property && existingKind === Property) {
                         grammarErrorOnNode(name, Diagnostics.Duplicate_identifier_0, getTextOfNode(name));
                     }
                     else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
                         if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
-                            seen.set(effectiveName, currentKind | existingKind);
+                            seen[effectiveName] = currentKind | existingKind;
                         }
                         else {
                             return grammarErrorOnNode(name, Diagnostics.An_object_literal_cannot_have_multiple_get_Slashset_accessors_with_the_same_name);
@@ -20402,7 +20398,7 @@ namespace ts {
         }
 
         function checkGrammarJsxElement(node: JsxOpeningLikeElement) {
-            const seen = createSet();
+            const seen = createMap<boolean>();
             for (const attr of node.attributes) {
                 if (attr.kind === SyntaxKind.JsxSpreadAttribute) {
                     continue;
@@ -20410,8 +20406,8 @@ namespace ts {
 
                 const jsxAttr = (<JsxAttribute>attr);
                 const name = jsxAttr.name;
-                if (!seen.has(name.text)) {
-                    seen.add(name.text);
+                if (!seen[name.text]) {
+                    seen[name.text] = true;
                 }
                 else {
                     return grammarErrorOnNode(name, Diagnostics.JSX_elements_cannot_have_multiple_attributes_with_the_same_name);
@@ -20905,11 +20901,11 @@ namespace ts {
 
         function getAmbientModules(): Symbol[] {
             const result: Symbol[] = [];
-            globals.forEach((global, sym) => {
+            for (const sym in globals) {
                 if (ambientModuleSymbolRegex.test(sym)) {
-                    result.push(global);
+                    result.push(globals[sym]);
                 }
-            });
+            }
             return result;
         }
     }
diff --git a/src/compiler/collections.ts b/src/compiler/collections.ts
deleted file mode 100644
index 01f3da2b9d342..0000000000000
--- a/src/compiler/collections.ts
+++ /dev/null
@@ -1,609 +0,0 @@
-// NumberMap, StringMap, and StringSet shims
-/* @internal */
-namespace ts {
-    // The global Map object. This may not be available, so we must test for it.
-    // Non-ES6 native maps don't support constructor arguments, so `createMap` must provide that functionality.
-    declare const Map: { new<K, V>(): Map<K, V> } | undefined;
-    const usingNativeMaps = typeof Map !== "undefined";
-    // tslint:disable-next-line:no-in-operator
-    const usingES6NativeMaps = usingNativeMaps && "keys" in Map.prototype && "values" in Map.prototype && "entries" in Map.prototype;
-
-    /** Extra Map methods that may not be available, so we must provide fallbacks. */
-    interface ES6Map<K, V> extends Map<K, V> {
-        keys(): Iterator<K>;
-        values(): Iterator<V>;
-        entries(): Iterator<[K, V]>;
-    }
-
-    /** Simplified ES6 Iterator interface. */
-    interface Iterator<T> {
-        next(): { value: T, done: false } | { value: never, done: true };
-    }
-
-    /**
-     * Provides Map-like functionality for ES5 runtimes.
-     * This is intentionally *not* a full Map shim, and doesn't provide iterators (which aren't available for IE Maps anyway).
-     * We can only efficiently support strings and number keys, and iteration will always yield stringified keys.
-     */
-    class ShimMap<K extends string | number, V> implements Map<K, V> {
-        private data = createDictionaryModeObject<V>();
-
-        /*
-        So long as `K extends string | number`, we can cast `key as string` and insert it into the map.
-        However, `forEach` will iterate over strings because values are stringified before being put in the map.
-        */
-
-        constructor() {}
-
-        clear(): void {
-            this.data = createDictionaryModeObject<V>();
-        }
-
-        delete(key: K): boolean {
-            const had = this.has(key);
-            if (had) {
-                delete this.data[key as string];
-            }
-            return had;
-        }
-
-        get(key: K): V {
-            return this.data[key as string];
-        }
-
-        has(key: K): boolean {
-            // tslint:disable-next-line:no-in-operator
-            return (key as string) in this.data;
-        }
-
-        set(key: K, value: V): void {
-            this.data[key as string] = value;
-        }
-
-        forEach(action: (value: V, key: string) => void): void {
-            for (const key in this.data) {
-                action(this.data[key], key);
-            }
-        }
-    }
-
-    const MapCtr = usingNativeMaps ? Map : ShimMap;
-    /**
-     * In runtimes without Maps, this is implemented using an object.
-     * `pairs` is an optional list of entries to add to the new map.
-     */
-    export function createMap<K extends string | number, V>(pairs?: [K, V][]): Map<K, V> {
-        const map = new MapCtr<K, V>();
-
-        if (pairs) {
-            for (const [key, value] of pairs) {
-                map.set(key, value);
-            }
-        }
-
-        return map;
-    }
-
-    const createObject = Object.create;
-    function createDictionaryModeObject<T>(): MapLike<T> {
-        const map = createObject(null); // tslint:disable-line:no-null-keyword
-
-        // Using 'delete' on an object causes V8 to put the object in dictionary mode.
-        // This disables creation of hidden classes, which are expensive when an object is
-        // constantly changing shape.
-        map["__"] = undefined;
-        delete map["__"];
-
-        return map;
-    }
-
-    /**
-     * Iterates over entries in the map, returning the first output of `getResult` that is not `undefined`.
-     * Only works for strings because shims iterate with `for-in`.
-     */
-    export const findInMap: <V, U>(map: Map<string, V>, getResult: (value: V, key: string) => U | undefined) => U | undefined = usingES6NativeMaps
-        ? <V, U>(map: ES6Map<string, V>, f: (value: V, key: string) => U | undefined) => {
-            const iter = map.entries();
-            while (true) {
-                const { value: pair, done } = iter.next();
-                if (done) {
-                    return undefined;
-                }
-                const [key, value] = pair;
-                const result = f(value, key);
-                if (result !== undefined) {
-                    return result;
-                }
-            }
-        }
-        : <V, U>(map: Map<string, V>, f: (value: V, key: string) => U | undefined) => {
-            let result: U | undefined;
-            map.forEach((value, key) => {
-                if (result === undefined)
-                    result = f(value, key);
-            });
-            return result;
-        };
-
-    /**
-     * Whether `predicate` is true for at least one entry in the map.
-     * Only works for strings because shims iterate with `for-in`.
-     */
-    export const someInMap: <V>(map: Map<string, V>, predicate: (value: V, key: string) => boolean) => boolean = usingES6NativeMaps
-        ? <V>(map: ES6Map<string, V>, predicate: (value: V, key: string) => boolean) =>
-            someInIterator(map.entries(), ([key, value]) => predicate(value, key))
-        : <V>(map: Map<string, V>, predicate: (value: V, key: string) => boolean) => {
-            let found = false;
-            map.forEach((value, key) => {
-                found = found || predicate(value, key);
-            });
-            return found;
-        };
-
-    /**
-     * Whether `predicate` is true for at least one key in the map.
-     * Only works for strings because shims iterate with `for-in`.
-     */
-    export const someKeyInMap: (map: Map<string, any>, predicate: (key: string) => boolean) => boolean = usingES6NativeMaps
-        ? (map: ES6Map<string, any>, predicate: (key: string) => boolean) => someInIterator(map.keys(), predicate)
-        : (map: Map<string, any>, predicate: (key: string) => boolean) =>
-            someInMap(map, (_value, key) => predicate(key));
-
-    /** Whether `predicate` is true for at least one value in the map. */
-    export const someValueInMap: <T>(map: Map<any, T>, predicate: (value: T) => boolean) => boolean = usingES6NativeMaps
-        ? <T>(map: ES6Map<any, T>, predicate: (value: T) => boolean) =>
-            someInIterator(map.values(), predicate)
-        : someInMap;
-
-    function someInIterator<T>(iterator: Iterator<T>, predicate: (value: T) => boolean): boolean {
-        while (true) {
-            const { value, done } = iterator.next();
-            if (done) {
-                return false;
-            }
-            if (predicate(value)) {
-                return true;
-            }
-        }
-    }
-
-    /**
-     * Equivalent to the ES6 code:
-     * `for (const key of map.keys()) action(key);`
-     * Only works for strings because shims iterate with `for-in`.
-     */
-    export const forEachKeyInMap: (map: Map<string, any>, action: (key: string) => void) => void = usingES6NativeMaps
-        ? (map: ES6Map<string, any>, action: (key: string) => void) => {
-            const iter: Iterator<string> = map.keys();
-            while (true) {
-                const { value: key, done } = iter.next();
-                if (done) {
-                    return;
-                }
-                action(key);
-            }
-        }
-        : (map: Map<string, any>, action: (key: string) => void) => {
-            map.forEach((_value, key) => action(key));
-        };
-
-    /** Size of a map. */
-    export const mapSize: (map: Map<any, any>) => number = usingNativeMaps
-        ? map => (map as any).size
-        : map => {
-            let size = 0;
-            map.forEach(() => { size++; });
-            return size;
-        };
-
-    /** Convert a Map to a MapLike. */
-    export function mapLikeOfMap<T>(map: Map<string, T>): MapLike<T> {
-        const obj = createDictionaryModeObject<T>();
-        map.forEach((value, key) => {
-            obj[key] = value;
-        });
-        return obj;
-    }
-
-    /** Create a map from a MapLike. This is useful for writing large maps as object literals. */
-    export function mapOfMapLike<T>(object: MapLike<T>): Map<string, T> {
-        const map = createMap<string, T>();
-        // Copies keys/values from template. Note that for..in will not throw if
-        // template is undefined, and instead will just exit the loop.
-        for (const key in object) if (hasProperty(object, key)) {
-            map.set(key, object[key]);
-        }
-        return map;
-    }
-
-    class ShimStringSet implements Set<string> {
-        private data = createDictionaryModeObject<true>();
-
-        constructor() {}
-
-        add(value: string) {
-            this.data[value] = true;
-        }
-
-        clear() {
-            this.data = createDictionaryModeObject<true>();
-        }
-
-        delete(value: string): boolean {
-            const had = this.has(value);
-            if (had) {
-                delete this.data[value];
-            }
-            return had;
-        }
-
-        forEach(action: (value: string) => void) {
-            for (const value in this.data) {
-                action(value);
-            }
-        }
-
-        has(value: string) {
-            // tslint:disable-next-line:no-in-operator
-            return value in this.data;
-        }
-
-        isEmpty() {
-            for (const _ in this.data) {
-                // TODO: GH#11734
-                _;
-                return false;
-            }
-            return true;
-        }
-    }
-
-    declare const Set: { new(): Set<string> } | undefined;
-    const usingNativeSets = typeof Set !== "undefined";
-
-    const SetCtr = usingNativeSets ? Set : ShimStringSet;
-    export function createSet(): Set<string> {
-        return new SetCtr();
-    }
-
-    /** False if there are any values in the set. */
-    export const setIsEmpty: (set: Set<string>) => boolean = usingNativeSets
-        ? set => (set as any).size === 0
-        : (set: ShimStringSet) => set.isEmpty();
-
-    // Map utilities
-
-    /** Set a value in a map, then return that value. */
-    export function setAndReturn<K, V>(map: Map<K, V>, key: K, value: V): V {
-        map.set(key, value);
-        return value;
-    }
-
-    /** False if there are any entries in the map. */
-    export function mapIsEmpty(map: Map<any, any>): boolean {
-        return !someKeyInMap(map, () => true);
-    }
-
-    /** Create a new copy of a Map. */
-    export function cloneMap<T>(map: Map<string, T>) {
-        const clone = createMap<string, T>();
-        copyMapEntriesFromTo(map, clone);
-        return clone;
-    }
-
-    /**
-     * Performs a shallow copy of the properties from a source Map to a target Map
-     *
-     * @param source A map from which properties should be copied.
-     * @param target A map to which properties should be copied.
-     */
-    export function copyMapEntriesFromTo<K, V>(source: Map<K, V>, target: Map<K, V>): void {
-        source.forEach((value: V, key: K) => {
-            target.set(key, value);
-        });
-    }
-
-    /**
-     * Equivalent to `Array.from(map.keys())`.
-     * Only works for strings because shims iterate with `for-in`.
-     */
-    export function keysOfMap(map: Map<string, any>): string[] {
-        const keys: string[] = [];
-        forEachKeyInMap(map, key => { keys.push(key); });
-        return keys;
-    }
-
-    /** Equivalent to `Array.from(map.values())`. */
-    export function valuesOfMap<V>(map: Map<any, V>): V[] {
-        const values: V[] = [];
-        map.forEach((value) => { values.push(value); });
-        return values;
-    }
-
-    /** Return a new map with each key transformed by `getNewKey`. */
-    export function transformKeys<T>(map: Map<string, T>, getNewKey: (key: string) => string): Map<string, T> {
-        const newMap = createMap<string, T>();
-        map.forEach((value, key) => {
-            newMap.set(getNewKey(key), value);
-        });
-        return newMap;
-    }
-
-    /** Replace each value with the result of calling `getNewValue`. */
-    export function updateMapValues<V>(map: Map<any, V>, getNewValue: (value: V) => V): void {
-        map.forEach((value, key) => {
-            map.set(key, getNewValue(value));
-        });
-    }
-
-    /**
-     * Change the value at `key` by applying the given function to it.
-     * If there is no value at `key` then `getNewValue` will be passed `undefined`.
-     */
-    export function modifyValue<K, V>(map: Map<K, V>, key: K, getNewValue: (value: V) => V) {
-        map.set(key, getNewValue(map.get(key)));
-    }
-
-    /**
-     * Get a value in the map, or if not already present, set and return it.
-     * Treats entries set to `undefined` as equivalent to not being set (saving a call to `has`).
-     */
-    export function getOrUpdate<K, V>(map: Map<K, V>, key: K, getValue: (key: K) => V): V {
-        const value = map.get(key);
-        return value !== undefined ? value : setAndReturn(map, key, getValue(key));
-    }
-
-    /** Like `getOrUpdate`, but recognizes `undefined` as having been already set. */
-    export function getOrUpdateAndAllowUndefined<K, V>(map: Map<K, V>, key: K, getValue: (key: K) => V): V {
-        return map.has(key) ? map.get(key) : setAndReturn(map, key, getValue(key));
-    }
-
-    /**
-     * Sets the the value if the key is not already in the map.
-     * Returns whether the value was set.
-     */
-    export function setIfNotSet<K, V>(map: Map<K, V>, key: K, value: V): boolean {
-        const shouldSet = !map.has(key);
-        if (shouldSet) {
-            map.set(key, value);
-        }
-        return shouldSet;
-    }
-
-    /** Deletes an entry from a map and returns it; or returns undefined if the key was not in the map. */
-    export function tryDelete<K, V>(map: Map<K, V>, key: K): V | undefined {
-        const current = map.get(key);
-        if (current !== undefined) {
-            map.delete(key);
-            return current;
-        }
-        else {
-            return undefined;
-        }
-    }
-
-    /**
-     * Creates a map from the elements of an array.
-     *
-     * @param array the array of input elements.
-     * @param makeKey a function that produces a key for a given element.
-     *
-     * This function makes no effort to avoid collisions; if any two elements produce
-     * the same key with the given 'makeKey' function, then the element with the higher
-     * index in the array will be the one associated with the produced key.
-     */
-    export function arrayToMap<T>(array: T[], makeKey: (value: T) => string): Map<string, T>;
-    export function arrayToMap<T, U>(array: T[], makeKey: (value: T) => string, makeValue: (value: T) => U): Map<string, U>;
-    export function arrayToMap<T, U>(array: T[], makeKey: (value: T) => string, makeValue?: (value: T) => U): Map<string, T | U> {
-        const result = createMap<string, T | U>();
-        for (const value of array) {
-            result.set(makeKey(value), makeValue ? makeValue(value) : value);
-        }
-        return result;
-    }
-
-    /**
-     * Adds the value to an array of values associated with the key, and returns the array.
-     * Creates the array if it does not already exist.
-     */
-    export function multiMapAdd<K, V>(map: Map<K, V[]>, key: K, value: V): V[] {
-        const values = map.get(key);
-        if (values) {
-            values.push(value);
-            return values;
-        }
-        else {
-            return setAndReturn(map, key, [value]);
-        }
-    }
-
-    /**
-     * Removes a value from an array of values associated with the key.
-     * Does not preserve the order of those values.
-     * Does nothing if `key` is not in `map`, or `value` is not in `map[key]`.
-     */
-    export function multiMapRemove<K, V>(map: Map<K, V[]>, key: K, value: V): void {
-        const values = map.get(key);
-        if (values) {
-            unorderedRemoveItem(values, value);
-            if (!values.length) {
-                map.delete(key);
-            }
-        }
-    }
-
-    /** True if the maps have the same keys and values. */
-    export function mapsAreEqual<V>(left: Map<string, V>, right: Map<string, V>, valuesAreEqual?: (left: V, right: V) => boolean): boolean {
-        if (left === right) return true;
-        if (!left || !right) return false;
-        const someInLeftHasNoMatch = someInMap(left, (leftValue, leftKey) => {
-            if (!right.has(leftKey)) return true;
-            const rightValue = right.get(leftKey);
-            return !(valuesAreEqual ? valuesAreEqual(leftValue, rightValue) : leftValue === rightValue);
-        });
-        if (someInLeftHasNoMatch) return false;
-        const someInRightHasNoMatch = someKeyInMap(right, rightKey => !left.has(rightKey));
-        return !someInRightHasNoMatch;
-    }
-
-    /**
-     * Creates a sorted array of keys.
-     * Sorts keys according to the iteration order they would have if they were in an object, instead of from a Map.
-     * This is so that tests run consistently whether or not we have a Map shim in place.
-     * The difference between Map iteration order and V8 object insertion order is that V8 moves natural-number-like keys to the front.
-     */
-    export function sortInV8ObjectInsertionOrder<T>(values: T[], toKey: (t: T) => string): T[] {
-        const naturalNumberKeys: T[] = [];
-        const allOtherKeys: T[] = [];
-        for (const value of values) {
-            // "0" looks like a natural but "08" doesn't.
-            const looksLikeNatural = /^(0|([1-9]\d*))$/.test(toKey(value));
-            (looksLikeNatural ? naturalNumberKeys : allOtherKeys).push(value);
-        }
-        function toInt(value: T): number {
-            return parseInt(toKey(value), 10);
-        }
-        naturalNumberKeys.sort((a, b) => toInt(a) - toInt(b));
-        return naturalNumberKeys.concat(allOtherKeys);
-    }
-
-    // Set utilities
-
-    /** Union of the `getSet` of each element in the array. */
-    export function setAggregate<T>(array: T[], getSet: (t: T) => Set<string>): Set<string> {
-        const result = createSet();
-        for (const value of array) {
-            copySetValuesFromTo(getSet(value), result);
-        }
-        return result;
-    }
-
-    /** Adds all values in `source` to `target`. */
-    function copySetValuesFromTo<T>(source: Set<T>, target: Set<T>): void {
-        source.forEach(value => target.add(value));
-    }
-
-    /** Returns the values in `set` satisfying `predicate`. */
-    export function filterSetToArray<T>(set: Set<T>, predicate: (value: T) => boolean): T[] {
-        const result: T[] = [];
-        set.forEach(value => {
-            if (predicate(value)) {
-                result.push(value);
-            }
-        });
-        return result;
-    }
-
-    // MapLike utilities
-
-    const hasOwnProperty = Object.prototype.hasOwnProperty;
-
-    export function clone<T>(object: T): T {
-        const result: any = {};
-        for (const id in object) {
-            if (hasOwnProperty.call(object, id)) {
-                result[id] = (<any>object)[id];
-            }
-        }
-        return result;
-    }
-
-    /**
-     * Indicates whether a map-like contains an own property with the specified key.
-     *
-     * NOTE: This is intended for use only with MapLike<T> objects. For Map<T> objects, use
-     *       the 'in' operator.
-     *
-     * @param map A map-like.
-     * @param key A property key.
-     */
-    export function hasProperty<T>(map: MapLike<T>, key: string): boolean {
-        return hasOwnProperty.call(map, key);
-    }
-
-    /**
-     * Gets the value of an owned property in a map-like.
-     *
-     * NOTE: This is intended for use only with MapLike<T> objects. For Map<T> objects, use
-     *       an indexer.
-     *
-     * @param map A map-like.
-     * @param key A property key.
-     */
-    export function getProperty<T>(map: MapLike<T>, key: string): T | undefined {
-        return hasOwnProperty.call(map, key) ? map[key] : undefined;
-    }
-
-    /**
-     * Gets the owned, enumerable property keys of a map-like.
-     *
-     * NOTE: This is intended for use with MapLike<T> objects. For Map<T> objects, use
-     *       Object.keys instead as it offers better performance.
-     *
-     * @param map A map-like.
-     */
-    export function getOwnKeys<T>(map: MapLike<T>): string[] {
-        const keys: string[] = [];
-        for (const key in map) if (hasOwnProperty.call(map, key)) {
-            keys.push(key);
-        }
-        return keys;
-    }
-
-    export function assign<T1 extends MapLike<{}>, T2, T3>(t: T1, arg1: T2, arg2: T3): T1 & T2 & T3;
-    export function assign<T1 extends MapLike<{}>, T2>(t: T1, arg1: T2): T1 & T2;
-    export function assign<T1 extends MapLike<{}>>(t: T1, ...args: any[]): any;
-    export function assign<T1 extends MapLike<{}>>(t: T1, ...args: any[]) {
-        for (const arg of args) {
-            for (const p of getOwnKeys(arg)) {
-                t[p] = arg[p];
-            }
-        }
-        return t;
-    }
-
-    /**
-     * Reduce the properties defined on a map-like (but not from its prototype chain).
-     *
-     * @param map The map-like to reduce
-     * @param callback An aggregation function that is called for each entry in the map
-     * @param initial The initial value for the reduction.
-     */
-    export function reduceOwnProperties<T, U>(map: MapLike<T>, callback: (aggregate: U, value: T, key: string) => U, initial: U): U {
-        let result = initial;
-        for (const key in map) if (hasOwnProperty.call(map, key)) {
-            result = callback(result, map[key], String(key));
-        }
-        return result;
-    }
-
-    /**
-     * Performs a shallow equality comparison of the contents of two map-likes.
-     *
-     * @param left A map-like whose properties should be compared.
-     * @param right A map-like whose properties should be compared.
-     */
-    export function equalOwnProperties<T>(left: MapLike<T>, right: MapLike<T>, equalityComparer?: (left: T, right: T) => boolean) {
-        if (left === right) return true;
-        if (!left || !right) return false;
-        for (const key in left) if (hasOwnProperty.call(left, key)) {
-            if (!hasOwnProperty.call(right, key) === undefined) return false;
-            if (equalityComparer ? !equalityComparer(left[key], right[key]) : left[key] !== right[key]) return false;
-        }
-        for (const key in right) if (hasOwnProperty.call(right, key)) {
-            if (!hasOwnProperty.call(left, key)) return false;
-        }
-        return true;
-    }
-
-    export function extend<T1, T2>(first: T1, second: T2): T1 & T2 {
-        const result: T1 & T2 = <any>{};
-        for (const id in second) if (hasOwnProperty.call(second, id)) {
-            (result as any)[id] = (second as any)[id];
-        }
-        for (const id in first) if (hasOwnProperty.call(first, id)) {
-            (result as any)[id] = (first as any)[id];
-        }
-        return result;
-    }
-}
diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 87337cb1e2e5c..686af79a6cca0 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -65,7 +65,7 @@ namespace ts {
         },
         {
             name: "jsx",
-            type: mapOfMapLike({
+            type: createMap({
                 "preserve": JsxEmit.Preserve,
                 "react": JsxEmit.React
             }),
@@ -95,7 +95,7 @@ namespace ts {
         {
             name: "module",
             shortName: "m",
-            type: mapOfMapLike({
+            type: createMap({
                 "none": ModuleKind.None,
                 "commonjs": ModuleKind.CommonJS,
                 "amd": ModuleKind.AMD,
@@ -109,7 +109,7 @@ namespace ts {
         },
         {
             name: "newLine",
-            type: mapOfMapLike({
+            type: createMap({
                 "crlf": NewLineKind.CarriageReturnLineFeed,
                 "lf": NewLineKind.LineFeed
             }),
@@ -258,7 +258,7 @@ namespace ts {
         {
             name: "target",
             shortName: "t",
-            type: mapOfMapLike({
+            type: createMap({
                 "es3": ScriptTarget.ES3,
                 "es5": ScriptTarget.ES5,
                 "es6": ScriptTarget.ES2015,
@@ -294,7 +294,7 @@ namespace ts {
         },
         {
             name: "moduleResolution",
-            type: mapOfMapLike({
+            type: createMap({
                 "node": ModuleResolutionKind.NodeJs,
                 "classic": ModuleResolutionKind.Classic,
             }),
@@ -403,7 +403,7 @@ namespace ts {
             type: "list",
             element: {
                 name: "lib",
-                type: mapOfMapLike({
+                type: createMap({
                     // JavaScript only
                     "es5": "lib.es5.d.ts",
                     "es6": "lib.es2015.d.ts",
@@ -480,8 +480,8 @@ namespace ts {
 
     /* @internal */
     export interface OptionNameMap {
-        optionNameMap: Map<string, CommandLineOption>;
-        shortOptionNames: Map<string, string>;
+        optionNameMap: Map<CommandLineOption>;
+        shortOptionNames: Map<string>;
     }
 
     /* @internal */
@@ -500,12 +500,12 @@ namespace ts {
             return optionNameMapCache;
         }
 
-        const optionNameMap = createMap<string, CommandLineOption>();
-        const shortOptionNames = createMap<string, string>();
+        const optionNameMap = createMap<CommandLineOption>();
+        const shortOptionNames = createMap<string>();
         forEach(optionDeclarations, option => {
-            optionNameMap.set(option.name.toLowerCase(), option);
+            optionNameMap[option.name.toLowerCase()] = option;
             if (option.shortName) {
-                shortOptionNames.set(option.shortName, option.name);
+                shortOptionNames[option.shortName] = option.name;
             }
         });
 
@@ -515,16 +515,16 @@ namespace ts {
 
     /* @internal */
     export function createCompilerDiagnosticForInvalidCustomType(opt: CommandLineOptionOfCustomType): Diagnostic {
-        const namesOfType = keysOfMap(opt.type).map(key => `'${key}'`).join(", ");
+        const namesOfType = Object.keys(opt.type).map(key => `'${key}'`).join(", ");
         return createCompilerDiagnostic(Diagnostics.Argument_for_0_option_must_be_Colon_1, `--${opt.name}`, namesOfType);
     }
 
     /* @internal */
     export function parseCustomTypeOption(opt: CommandLineOptionOfCustomType, value: string, errors: Diagnostic[]) {
         const key = trimString((value || "")).toLowerCase();
-        const customType = opt.type.get(key);
-        if (customType !== undefined) {
-            return customType;
+        const map = opt.type;
+        if (key in map) {
+            return map[key];
         }
         else {
             errors.push(createCompilerDiagnosticForInvalidCustomType(opt));
@@ -577,13 +577,13 @@ namespace ts {
                     s = s.slice(s.charCodeAt(1) === CharacterCodes.minus ? 2 : 1).toLowerCase();
 
                     // Try to translate short option names to their full equivalents.
-                    const short = shortOptionNames.get(s);
-                    if (short !== undefined) {
-                        s = short;
+                    if (s in shortOptionNames) {
+                        s = shortOptionNames[s];
                     }
 
-                    const opt = optionNameMap.get(s);
-                    if (opt !== undefined) {
+                    if (s in optionNameMap) {
+                        const opt = optionNameMap[s];
+
                         if (opt.isTSConfigOnly) {
                             errors.push(createCompilerDiagnostic(Diagnostics.Option_0_can_only_be_specified_in_tsconfig_json_file, opt.name));
                         }
@@ -706,7 +706,7 @@ namespace ts {
      * @param fileNames array of filenames to be generated into tsconfig.json
      */
     /* @internal */
-    export function generateTSConfig(options: CompilerOptions, fileNames: string[]): { compilerOptions: MapLike<CompilerOptionsValue> } {
+    export function generateTSConfig(options: CompilerOptions, fileNames: string[]): { compilerOptions: Map<CompilerOptionsValue> } {
         const compilerOptions = extend(options, defaultInitCompilerOptions);
         const configurations: any = {
             compilerOptions: serializeCompilerOptions(compilerOptions)
@@ -718,7 +718,7 @@ namespace ts {
 
         return configurations;
 
-        function getCustomTypeMapOfCommandLineOption(optionDefinition: CommandLineOption): Map<string, string | number> | undefined {
+        function getCustomTypeMapOfCommandLineOption(optionDefinition: CommandLineOption): Map<string | number> | undefined {
             if (optionDefinition.type === "string" || optionDefinition.type === "number" || optionDefinition.type === "boolean") {
                 // this is of a type CommandLineOptionOfPrimitiveType
                 return undefined;
@@ -731,17 +731,18 @@ namespace ts {
             }
         }
 
-        function getNameOfCompilerOptionValue(value: CompilerOptionsValue, customTypeMap: Map<string, string | number>): string | undefined {
+        function getNameOfCompilerOptionValue(value: CompilerOptionsValue, customTypeMap: MapLike<string | number>): string | undefined {
             // There is a typeMap associated with this command-line option so use it to map value back to its name
-            return findInMap(customTypeMap, (customValue, key) => {
-                if (customValue === value) {
+            for (const key in customTypeMap) {
+                if (customTypeMap[key] === value) {
                     return key;
                 }
-            });
+            }
+            return undefined;
         }
 
-        function serializeCompilerOptions(options: CompilerOptions): MapLike<CompilerOptionsValue> {
-            const result = createMap<string, CompilerOptionsValue>();
+        function serializeCompilerOptions(options: CompilerOptions): Map<CompilerOptionsValue> {
+            const result = createMap<CompilerOptionsValue>();
             const optionsNameMap = getOptionNameMap().optionNameMap;
 
             for (const name in options) {
@@ -757,13 +758,13 @@ namespace ts {
                             break;
                         default:
                             const value = options[name];
-                            let optionDefinition = optionsNameMap.get(name.toLowerCase());
+                            let optionDefinition = optionsNameMap[name.toLowerCase()];
                             if (optionDefinition) {
                                 const customTypeMap = getCustomTypeMapOfCommandLineOption(optionDefinition);
                                 if (!customTypeMap) {
                                     // There is no map associated with this compiler option then use the value as-is
                                     // This is the case if the value is expect to be string, number, boolean or list of string
-                                    result.set(name, value);
+                                    result[name] = value;
                                 }
                                 else {
                                     if (optionDefinition.type === "list") {
@@ -771,11 +772,11 @@ namespace ts {
                                         for (const element of value as (string | number)[]) {
                                             convertedValue.push(getNameOfCompilerOptionValue(element, customTypeMap));
                                         }
-                                        result.set(name, convertedValue);
+                                        result[name] = convertedValue;
                                     }
                                     else {
                                         // There is a typeMap associated with this command-line option so use it to map value back to its name
-                                        result.set(name, getNameOfCompilerOptionValue(value, customTypeMap));
+                                        result[name] = getNameOfCompilerOptionValue(value, customTypeMap);
                                     }
                                 }
                             }
@@ -783,7 +784,7 @@ namespace ts {
                     }
                 }
             }
-            return mapLikeOfMap(result);
+            return result;
         }
     }
 
@@ -1024,8 +1025,8 @@ namespace ts {
         const optionNameMap = arrayToMap(optionDeclarations, opt => opt.name);
 
         for (const id in jsonOptions) {
-            const opt = optionNameMap.get(id);
-            if (opt !== undefined) {
+            if (id in optionNameMap) {
+                const opt = optionNameMap[id];
                 defaultOptions[opt.name] = convertJsonOption(opt, jsonOptions[id], basePath, errors);
             }
             else {
@@ -1061,9 +1062,8 @@ namespace ts {
 
     function convertJsonOptionOfCustomType(opt: CommandLineOptionOfCustomType, value: string, errors: Diagnostic[]) {
         const key = value.toLowerCase();
-        const val = opt.type.get(key);
-        if (val !== undefined) {
-            return val;
+        if (key in opt.type) {
+            return opt.type[key];
         }
         else {
             errors.push(createCompilerDiagnosticForInvalidCustomType(opt));
@@ -1172,12 +1172,12 @@ namespace ts {
         // Literal file names (provided via the "files" array in tsconfig.json) are stored in a
         // file map with a possibly case insensitive key. We use this map later when when including
         // wildcard paths.
-        const literalFileMap = createMap<string, string>();
+        const literalFileMap = createMap<string>();
 
         // Wildcard paths (provided via the "includes" array in tsconfig.json) are stored in a
         // file map with a possibly case insensitive key. We use this map to store paths matched
         // via wildcard, and to handle extension priority.
-        const wildcardFileMap = createMap<string, string>();
+        const wildcardFileMap = createMap<string>();
 
         if (include) {
             include = validateSpecs(include, errors, /*allowTrailingRecursion*/ false);
@@ -1191,7 +1191,7 @@ namespace ts {
         // file map that marks whether it was a regular wildcard match (with a `*` or `?` token),
         // or a recursive directory. This information is used by filesystem watchers to monitor for
         // new entries in these paths.
-        const wildcardDirectories: Map<string, WatchDirectoryFlags> = getWildcardDirectories(include, exclude, basePath, host.useCaseSensitiveFileNames);
+        const wildcardDirectories: Map<WatchDirectoryFlags> = getWildcardDirectories(include, exclude, basePath, host.useCaseSensitiveFileNames);
 
         // Rather than requery this for each file and filespec, we query the supported extensions
         // once and store it on the expansion context.
@@ -1202,7 +1202,7 @@ namespace ts {
         if (fileNames) {
             for (const fileName of fileNames) {
                 const file = combinePaths(basePath, fileName);
-                literalFileMap.set(keyMapper(file), file);
+                literalFileMap[keyMapper(file)] = file;
             }
         }
 
@@ -1225,17 +1225,18 @@ namespace ts {
                 removeWildcardFilesWithLowerPriorityExtension(file, wildcardFileMap, supportedExtensions, keyMapper);
 
                 const key = keyMapper(file);
-                if (!literalFileMap.has(key)) {
-                    setIfNotSet(wildcardFileMap, key, file);
+                if (!(key in literalFileMap) && !(key in wildcardFileMap)) {
+                    wildcardFileMap[key] = file;
                 }
             }
         }
 
-        const literalFiles = valuesOfMap(literalFileMap);
-        const wildcardFiles = valuesOfMap(wildcardFileMap).sort(host.useCaseSensitiveFileNames ? compareStrings : compareStringsCaseInsensitive);
+        const literalFiles = reduceProperties(literalFileMap, addFileToOutput, []);
+        const wildcardFiles = reduceProperties(wildcardFileMap, addFileToOutput, []);
+        wildcardFiles.sort(host.useCaseSensitiveFileNames ? compareStrings : compareStringsCaseInsensitive);
         return {
             fileNames: literalFiles.concat(wildcardFiles),
-            wildcardDirectories: mapLikeOfMap(wildcardDirectories)
+            wildcardDirectories
         };
     }
 
@@ -1276,7 +1277,7 @@ namespace ts {
         //  /a/b/a?z    - Watch /a/b directly to catch any new file matching a?z
         const rawExcludeRegex = getRegularExpressionForWildcard(exclude, path, "exclude");
         const excludeRegex = rawExcludeRegex && new RegExp(rawExcludeRegex, useCaseSensitiveFileNames ? "" : "i");
-        const wildcardDirectories = createMap<string, WatchDirectoryFlags>();
+        const wildcardDirectories = createMap<WatchDirectoryFlags>();
         if (include !== undefined) {
             const recursiveKeys: string[] = [];
             for (const file of include) {
@@ -1289,9 +1290,9 @@ namespace ts {
                 if (match) {
                     const key = useCaseSensitiveFileNames ? match[0] : match[0].toLowerCase();
                     const flags = watchRecursivePattern.test(name) ? WatchDirectoryFlags.Recursive : WatchDirectoryFlags.None;
-                    const existingFlags = wildcardDirectories.get(key);
+                    const existingFlags = wildcardDirectories[key];
                     if (existingFlags === undefined || existingFlags < flags) {
-                        wildcardDirectories.set(key, flags);
+                        wildcardDirectories[key] = flags;
                         if (flags === WatchDirectoryFlags.Recursive) {
                             recursiveKeys.push(key);
                         }
@@ -1300,13 +1301,13 @@ namespace ts {
             }
 
             // Remove any subpaths under an existing recursively watched directory.
-            forEachKeyInMap(wildcardDirectories, key => {
+            for (const key in wildcardDirectories) {
                 for (const recursiveKey of recursiveKeys) {
                     if (key !== recursiveKey && containsPath(recursiveKey, key, path, !useCaseSensitiveFileNames)) {
-                        wildcardDirectories.delete(key);
+                        delete wildcardDirectories[key];
                     }
                 }
-            });
+            }
         }
 
         return wildcardDirectories;
@@ -1320,13 +1321,13 @@ namespace ts {
      * @param extensionPriority The priority of the extension.
      * @param context The expansion context.
      */
-    function hasFileWithHigherPriorityExtension(file: string, literalFiles: Map<string, string>, wildcardFiles: Map<string, string>, extensions: string[], keyMapper: (value: string) => string) {
+    function hasFileWithHigherPriorityExtension(file: string, literalFiles: Map<string>, wildcardFiles: Map<string>, extensions: string[], keyMapper: (value: string) => string) {
         const extensionPriority = getExtensionPriority(file, extensions);
         const adjustedExtensionPriority = adjustExtensionPriority(extensionPriority);
         for (let i = ExtensionPriority.Highest; i < adjustedExtensionPriority; i++) {
             const higherPriorityExtension = extensions[i];
             const higherPriorityPath = keyMapper(changeExtension(file, higherPriorityExtension));
-            if (literalFiles.has(higherPriorityPath) || wildcardFiles.has(higherPriorityPath)) {
+            if (higherPriorityPath in literalFiles || higherPriorityPath in wildcardFiles) {
                 return true;
             }
         }
@@ -1342,16 +1343,27 @@ namespace ts {
      * @param extensionPriority The priority of the extension.
      * @param context The expansion context.
      */
-    function removeWildcardFilesWithLowerPriorityExtension(file: string, wildcardFiles: Map<string, string>, extensions: string[], keyMapper: (value: string) => string) {
+    function removeWildcardFilesWithLowerPriorityExtension(file: string, wildcardFiles: Map<string>, extensions: string[], keyMapper: (value: string) => string) {
         const extensionPriority = getExtensionPriority(file, extensions);
         const nextExtensionPriority = getNextLowestExtensionPriority(extensionPriority);
         for (let i = nextExtensionPriority; i < extensions.length; i++) {
             const lowerPriorityExtension = extensions[i];
             const lowerPriorityPath = keyMapper(changeExtension(file, lowerPriorityExtension));
-            wildcardFiles.delete(lowerPriorityPath);
+            delete wildcardFiles[lowerPriorityPath];
         }
     }
 
+    /**
+     * Adds a file to an array of files.
+     *
+     * @param output The output array.
+     * @param file The file path.
+     */
+    function addFileToOutput(output: string[], file: string) {
+        output.push(file);
+        return output;
+    }
+
     /**
      * Gets a case sensitive key.
      *
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 208b4d0931a82..f207cf010e2a5 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -1,5 +1,4 @@
-/// <reference path="collections.ts" />
-/// <reference path="types.ts"/>
+/// <reference path="types.ts"/>
 /// <reference path="performance.ts" />
 
 /* @internal */
@@ -19,11 +18,31 @@ namespace ts {
         True = -1
     }
 
+    const createObject = Object.create;
+
     // More efficient to create a collator once and use its `compare` than to call `a.localeCompare(b)` many times.
     export const collator: { compare(a: string, b: string): number } = typeof Intl === "object" && typeof Intl.Collator === "function" ? new Intl.Collator() : undefined;
 
+    export function createMap<T>(template?: MapLike<T>): Map<T> {
+        const map: Map<T> = createObject(null); // tslint:disable-line:no-null-keyword
+
+        // Using 'delete' on an object causes V8 to put the object in dictionary mode.
+        // This disables creation of hidden classes, which are expensive when an object is
+        // constantly changing shape.
+        map["__"] = undefined;
+        delete map["__"];
+
+        // Copies keys/values from template. Note that for..in will not throw if
+        // template is undefined, and instead will just exit the loop.
+        for (const key in template) if (hasOwnProperty.call(template, key)) {
+            map[key] = template[key];
+        }
+
+        return map;
+    }
+
     export function createFileMap<T>(keyMapper?: (key: string) => string): FileMap<T> {
-        const files = createMap<string, T>();
+        let files = createMap<T>();
         return {
             get,
             set,
@@ -35,33 +54,39 @@ namespace ts {
         };
 
         function forEachValueInMap(f: (key: Path, value: T) => void) {
-            files.forEach((value, key) => f(key as Path, value));
+            for (const key in files) {
+                f(<Path>key, files[key]);
+            }
         }
 
-        function getKeys(): Path[] {
-            return keysOfMap(files) as Path[];
+        function getKeys() {
+            const keys: Path[] = [];
+            for (const key in files) {
+                keys.push(<Path>key);
+            }
+            return keys;
         }
 
         // path should already be well-formed so it does not need to be normalized
         function get(path: Path): T {
-            return files.get(toKey(path));
+            return files[toKey(path)];
         }
 
         function set(path: Path, value: T) {
-            files.set(toKey(path), value);
+            files[toKey(path)] = value;
         }
 
         function contains(path: Path) {
-            return files.has(toKey(path));
+            return toKey(path) in files;
         }
 
         function remove(path: Path) {
             const key = toKey(path);
-            files.delete(key);
+            delete files[key];
         }
 
         function clear() {
-            files.clear();
+            files = createMap<T>();
         }
 
         function toKey(path: Path): string {
@@ -682,6 +707,242 @@ namespace ts {
         return initial;
     }
 
+    const hasOwnProperty = Object.prototype.hasOwnProperty;
+
+    /**
+     * Indicates whether a map-like contains an own property with the specified key.
+     *
+     * NOTE: This is intended for use only with MapLike<T> objects. For Map<T> objects, use
+     *       the 'in' operator.
+     *
+     * @param map A map-like.
+     * @param key A property key.
+     */
+    export function hasProperty<T>(map: MapLike<T>, key: string): boolean {
+        return hasOwnProperty.call(map, key);
+    }
+
+    /**
+     * Gets the value of an owned property in a map-like.
+     *
+     * NOTE: This is intended for use only with MapLike<T> objects. For Map<T> objects, use
+     *       an indexer.
+     *
+     * @param map A map-like.
+     * @param key A property key.
+     */
+    export function getProperty<T>(map: MapLike<T>, key: string): T | undefined {
+        return hasOwnProperty.call(map, key) ? map[key] : undefined;
+    }
+
+    /**
+     * Gets the owned, enumerable property keys of a map-like.
+     *
+     * NOTE: This is intended for use with MapLike<T> objects. For Map<T> objects, use
+     *       Object.keys instead as it offers better performance.
+     *
+     * @param map A map-like.
+     */
+    export function getOwnKeys<T>(map: MapLike<T>): string[] {
+        const keys: string[] = [];
+        for (const key in map) if (hasOwnProperty.call(map, key)) {
+            keys.push(key);
+        }
+        return keys;
+    }
+
+    /**
+     * Enumerates the properties of a Map<T>, invoking a callback and returning the first truthy result.
+     *
+     * @param map A map for which properties should be enumerated.
+     * @param callback A callback to invoke for each property.
+     */
+    export function forEachProperty<T, U>(map: Map<T>, callback: (value: T, key: string) => U): U {
+        let result: U;
+        for (const key in map) {
+            if (result = callback(map[key], key)) break;
+        }
+        return result;
+    }
+
+    /**
+     * Returns true if a Map<T> has some matching property.
+     *
+     * @param map A map whose properties should be tested.
+     * @param predicate An optional callback used to test each property.
+     */
+    export function someProperties<T>(map: Map<T>, predicate?: (value: T, key: string) => boolean) {
+        for (const key in map) {
+            if (!predicate || predicate(map[key], key)) return true;
+        }
+        return false;
+    }
+
+    /**
+     * Performs a shallow copy of the properties from a source Map<T> to a target MapLike<T>
+     *
+     * @param source A map from which properties should be copied.
+     * @param target A map to which properties should be copied.
+     */
+    export function copyProperties<T>(source: Map<T>, target: MapLike<T>): void {
+        for (const key in source) {
+            target[key] = source[key];
+        }
+    }
+
+    export function assign<T1 extends MapLike<{}>, T2, T3>(t: T1, arg1: T2, arg2: T3): T1 & T2 & T3;
+    export function assign<T1 extends MapLike<{}>, T2>(t: T1, arg1: T2): T1 & T2;
+    export function assign<T1 extends MapLike<{}>>(t: T1, ...args: any[]): any;
+    export function assign<T1 extends MapLike<{}>>(t: T1, ...args: any[]) {
+        for (const arg of args) {
+            for (const p of getOwnKeys(arg)) {
+                t[p] = arg[p];
+            }
+        }
+        return t;
+    }
+
+    /**
+     * Reduce the properties of a map.
+     *
+     * NOTE: This is intended for use with Map<T> objects. For MapLike<T> objects, use
+     *       reduceOwnProperties instead as it offers better runtime safety.
+     *
+     * @param map The map to reduce
+     * @param callback An aggregation function that is called for each entry in the map
+     * @param initial The initial value for the reduction.
+     */
+    export function reduceProperties<T, U>(map: Map<T>, callback: (aggregate: U, value: T, key: string) => U, initial: U): U {
+        let result = initial;
+        for (const key in map) {
+            result = callback(result, map[key], String(key));
+        }
+        return result;
+    }
+
+    /**
+     * Reduce the properties defined on a map-like (but not from its prototype chain).
+     *
+     * NOTE: This is intended for use with MapLike<T> objects. For Map<T> objects, use
+     *       reduceProperties instead as it offers better performance.
+     *
+     * @param map The map-like to reduce
+     * @param callback An aggregation function that is called for each entry in the map
+     * @param initial The initial value for the reduction.
+     */
+    export function reduceOwnProperties<T, U>(map: MapLike<T>, callback: (aggregate: U, value: T, key: string) => U, initial: U): U {
+        let result = initial;
+        for (const key in map) if (hasOwnProperty.call(map, key)) {
+            result = callback(result, map[key], String(key));
+        }
+        return result;
+    }
+
+    /**
+     * Performs a shallow equality comparison of the contents of two map-likes.
+     *
+     * @param left A map-like whose properties should be compared.
+     * @param right A map-like whose properties should be compared.
+     */
+    export function equalOwnProperties<T>(left: MapLike<T>, right: MapLike<T>, equalityComparer?: (left: T, right: T) => boolean) {
+        if (left === right) return true;
+        if (!left || !right) return false;
+        for (const key in left) if (hasOwnProperty.call(left, key)) {
+            if (!hasOwnProperty.call(right, key) === undefined) return false;
+            if (equalityComparer ? !equalityComparer(left[key], right[key]) : left[key] !== right[key]) return false;
+        }
+        for (const key in right) if (hasOwnProperty.call(right, key)) {
+            if (!hasOwnProperty.call(left, key)) return false;
+        }
+        return true;
+    }
+
+    /**
+     * Creates a map from the elements of an array.
+     *
+     * @param array the array of input elements.
+     * @param makeKey a function that produces a key for a given element.
+     *
+     * This function makes no effort to avoid collisions; if any two elements produce
+     * the same key with the given 'makeKey' function, then the element with the higher
+     * index in the array will be the one associated with the produced key.
+     */
+    export function arrayToMap<T>(array: T[], makeKey: (value: T) => string): Map<T>;
+    export function arrayToMap<T, U>(array: T[], makeKey: (value: T) => string, makeValue: (value: T) => U): Map<U>;
+    export function arrayToMap<T, U>(array: T[], makeKey: (value: T) => string, makeValue?: (value: T) => U): Map<T | U> {
+        const result = createMap<T | U>();
+        for (const value of array) {
+            result[makeKey(value)] = makeValue ? makeValue(value) : value;
+        }
+        return result;
+    }
+
+    export function isEmpty<T>(map: Map<T>) {
+        for (const id in map) {
+            if (hasProperty(map, id)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    export function cloneMap<T>(map: Map<T>) {
+        const clone = createMap<T>();
+        copyProperties(map, clone);
+        return clone;
+    }
+
+    export function clone<T>(object: T): T {
+        const result: any = {};
+        for (const id in object) {
+            if (hasOwnProperty.call(object, id)) {
+                result[id] = (<any>object)[id];
+            }
+        }
+        return result;
+    }
+
+    export function extend<T1, T2>(first: T1, second: T2): T1 & T2 {
+        const result: T1 & T2 = <any>{};
+        for (const id in second) if (hasOwnProperty.call(second, id)) {
+            (result as any)[id] = (second as any)[id];
+        }
+        for (const id in first) if (hasOwnProperty.call(first, id)) {
+            (result as any)[id] = (first as any)[id];
+        }
+        return result;
+    }
+
+    /**
+     * Adds the value to an array of values associated with the key, and returns the array.
+     * Creates the array if it does not already exist.
+     */
+    export function multiMapAdd<V>(map: Map<V[]>, key: string | number, value: V): V[] {
+        const values = map[key];
+        if (values) {
+            values.push(value);
+            return values;
+        }
+        else {
+            return map[key] = [value];
+        }
+    }
+
+    /**
+     * Removes a value from an array of values associated with the key.
+     * Does not preserve the order of those values.
+     * Does nothing if `key` is not in `map`, or `value` is not in `map[key]`.
+     */
+    export function multiMapRemove<V>(map: Map<V[]>, key: string, value: V): void {
+        const values = map[key];
+        if (values) {
+            unorderedRemoveItem(values, value);
+            if (!values.length) {
+                delete map[key];
+            }
+        }
+    }
+
     /**
      * Tests whether a value is an array.
      */
@@ -780,10 +1041,10 @@ namespace ts {
         return text.replace(/{(\d+)}/g, (_match, index?) => args[+index + baseIndex]);
     }
 
-    export let localizedDiagnosticMessages: Map<string, string> = undefined;
+    export let localizedDiagnosticMessages: Map<string> = undefined;
 
     export function getLocaleSpecificMessage(message: DiagnosticMessage) {
-        return localizedDiagnosticMessages && localizedDiagnosticMessages.get(message.key) || message.message;
+        return localizedDiagnosticMessages && localizedDiagnosticMessages[message.key] || message.message;
     }
 
     export function createFileDiagnostic(file: SourceFile, start: number, length: number, message: DiagnosticMessage, ...args: (string | number)[]): Diagnostic;
diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index 0c3b2abf3f04d..6458183b23c90 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -59,7 +59,7 @@ namespace ts {
         let resultHasExternalModuleIndicator: boolean;
         let currentText: string;
         let currentLineMap: number[];
-        let currentIdentifiers: Map<string, string>;
+        let currentIdentifiers: Map<string>;
         let isCurrentFileExternalModule: boolean;
         let reportedDeclarationError = false;
         let errorNameNode: DeclarationName;
@@ -75,7 +75,7 @@ namespace ts {
         // and we could be collecting these paths from multiple files into single one with --out option
         let referencesOutput = "";
 
-        let usedTypeDirectiveReferences: Set<string>;
+        let usedTypeDirectiveReferences: Map<string>;
 
         // Emit references corresponding to each file
         const emittedReferencedFiles: SourceFile[] = [];
@@ -156,9 +156,9 @@ namespace ts {
         });
 
         if (usedTypeDirectiveReferences) {
-            usedTypeDirectiveReferences.forEach(directive => {
+            for (const directive in usedTypeDirectiveReferences) {
                 referencesOutput += `/// <reference types="${directive}" />${newLine}`;
-            });
+            }
         }
 
         return {
@@ -267,11 +267,11 @@ namespace ts {
             }
 
             if (!usedTypeDirectiveReferences) {
-                usedTypeDirectiveReferences = createSet();
+                usedTypeDirectiveReferences = createMap<string>();
             }
             for (const directive of typeReferenceDirectives) {
-                if (!usedTypeDirectiveReferences.has(directive)) {
-                    usedTypeDirectiveReferences.add(directive);
+                if (!(directive in usedTypeDirectiveReferences)) {
+                    usedTypeDirectiveReferences[directive] = directive;
                 }
             }
         }
@@ -535,14 +535,14 @@ namespace ts {
         // do not need to keep track of created temp names.
         function getExportDefaultTempVariableName(): string {
             const baseName = "_default";
-            if (!currentIdentifiers.has(baseName)) {
+            if (!(baseName in currentIdentifiers)) {
                 return baseName;
             }
             let count = 0;
             while (true) {
                 count++;
                 const name = baseName + "_" + count;
-                if (!currentIdentifiers.has(name)) {
+                if (!(name in currentIdentifiers)) {
                     return name;
                 }
             }
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index d0568293eb7a5..1051c9adca961 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -219,11 +219,11 @@ const _super = (function (geti, seti) {
 
         let nodeIdToGeneratedName: string[];
         let autoGeneratedIdToGeneratedName: string[];
-        let generatedNameSet: Set<string>;
+        let generatedNameSet: Map<string>;
         let tempFlags: TempFlags;
         let currentSourceFile: SourceFile;
         let currentText: string;
-        let currentFileIdentifiers: Map<string, string>;
+        let currentFileIdentifiers: Map<string>;
         let extendsEmitted: boolean;
         let assignEmitted: boolean;
         let decorateEmitted: boolean;
@@ -292,7 +292,7 @@ const _super = (function (geti, seti) {
             sourceMap.initialize(jsFilePath, sourceMapFilePath, sourceFiles, isBundledEmit);
             nodeIdToGeneratedName = [];
             autoGeneratedIdToGeneratedName = [];
-            generatedNameSet = createSet();
+            generatedNameSet = createMap<string>();
             isOwnFileEmit = !isBundledEmit;
 
             // Emit helpers from all the files
@@ -2645,16 +2645,15 @@ const _super = (function (geti, seti) {
 
         function isUniqueName(name: string): boolean {
             return !resolver.hasGlobalName(name) &&
-                !currentFileIdentifiers.has(name) &&
-                !generatedNameSet.has(name);
+                !hasProperty(currentFileIdentifiers, name) &&
+                !hasProperty(generatedNameSet, name);
         }
 
         function isUniqueLocalName(name: string, container: Node): boolean {
             for (let node = container; isNodeDescendantOf(node, container); node = node.nextContainer) {
-                if (node.locals) {
-                    const local = node.locals.get(name);
+                if (node.locals && hasProperty(node.locals, name)) {
                     // We conservatively include alias symbols to cover cases where they're emitted as locals
-                    if (local && local.flags & (SymbolFlags.Value | SymbolFlags.ExportValue | SymbolFlags.Alias)) {
+                    if (node.locals[name].flags & (SymbolFlags.Value | SymbolFlags.ExportValue | SymbolFlags.Alias)) {
                         return false;
                     }
                 }
@@ -2703,8 +2702,7 @@ const _super = (function (geti, seti) {
             while (true) {
                 const generatedName = baseName + i;
                 if (isUniqueName(generatedName)) {
-                    generatedNameSet.add(generatedName);
-                    return generatedName;
+                    return generatedNameSet[generatedName] = generatedName;
                 }
                 i++;
             }
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 13f1230896e84..c557e3514a5de 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -1622,7 +1622,7 @@ namespace ts {
         // flag and setting a parent node.
         const react = createIdentifier(reactNamespace || "React");
         react.flags &= ~NodeFlags.Synthesized;
-        // Set the parent that is in parse tree
+        // Set the parent that is in parse tree 
         // this makes sure that parent chain is intact for checker to traverse complete scope tree
         react.parent = getParseTreeNode(parent);
         return react;
@@ -2805,9 +2805,9 @@ namespace ts {
         return destEmitNode;
     }
 
-    function mergeTokenSourceMapRanges(sourceRanges: Map<SyntaxKind, TextRange>, destRanges: Map<SyntaxKind, TextRange>): Map<SyntaxKind, TextRange> {
-        if (!destRanges) destRanges = createMap<SyntaxKind, TextRange>();
-        copyMapEntriesFromTo(sourceRanges, destRanges);
+    function mergeTokenSourceMapRanges(sourceRanges: Map<TextRange>, destRanges: Map<TextRange>) {
+        if (!destRanges) destRanges = createMap<TextRange>();
+        copyProperties(sourceRanges, destRanges);
         return destRanges;
     }
 
@@ -2899,8 +2899,8 @@ namespace ts {
      */
     export function setTokenSourceMapRange<T extends Node>(node: T, token: SyntaxKind, range: TextRange) {
         const emitNode = getOrCreateEmitNode(node);
-        const tokenSourceMapRanges = emitNode.tokenSourceMapRanges || (emitNode.tokenSourceMapRanges = createMap<SyntaxKind, TextRange>());
-        tokenSourceMapRanges.set(token, range);
+        const tokenSourceMapRanges = emitNode.tokenSourceMapRanges || (emitNode.tokenSourceMapRanges = createMap<TextRange>());
+        tokenSourceMapRanges[token] = range;
         return node;
     }
 
@@ -2941,7 +2941,7 @@ namespace ts {
     export function getTokenSourceMapRange(node: Node, token: SyntaxKind) {
         const emitNode = node.emitNode;
         const tokenSourceMapRanges = emitNode && emitNode.tokenSourceMapRanges;
-        return tokenSourceMapRanges && tokenSourceMapRanges.get(token);
+        return tokenSourceMapRanges && tokenSourceMapRanges[token];
     }
 
     /**
@@ -3026,8 +3026,10 @@ namespace ts {
      * Here we check if alternative name was provided for a given moduleName and return it if possible.
      */
     function tryRenameExternalModule(moduleName: LiteralExpression, sourceFile: SourceFile) {
-        const rename = sourceFile.renamedDependencies && sourceFile.renamedDependencies.get(moduleName.text);
-        return rename && createLiteral(rename);
+        if (sourceFile.renamedDependencies && hasProperty(sourceFile.renamedDependencies, moduleName.text)) {
+            return createLiteral(sourceFile.renamedDependencies[moduleName.text]);
+        }
+        return undefined;
     }
 
     /**
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index ea33473fe40a6..a5b02f98fd382 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -491,7 +491,7 @@ namespace ts {
         let currentToken: SyntaxKind;
         let sourceText: string;
         let nodeCount: number;
-        let identifiers: Map<string, string>;
+        let identifiers: Map<string>;
         let identifierCount: number;
 
         let parsingContext: ParsingContext;
@@ -601,7 +601,7 @@ namespace ts {
 
             parseDiagnostics = [];
             parsingContext = 0;
-            identifiers = createMap<string, string>();
+            identifiers = createMap<string>();
             identifierCount = 0;
             nodeCount = 0;
 
@@ -1104,7 +1104,7 @@ namespace ts {
 
         function internIdentifier(text: string): string {
             text = escapeIdentifier(text);
-            return getOrUpdate(identifiers, text, text => text);
+            return identifiers[text] || (identifiers[text] = text);
         }
 
         // An identifier that starts with two underscores has an extra underscore character prepended to it to avoid issues
diff --git a/src/compiler/performance.ts b/src/compiler/performance.ts
index 6cb73e4d058c7..a48eb117e28b9 100644
--- a/src/compiler/performance.ts
+++ b/src/compiler/performance.ts
@@ -16,9 +16,9 @@ namespace ts.performance {
 
     let enabled = false;
     let profilerStart = 0;
-    let counts: Map<string, number>;
-    let marks: Map<string, number>;
-    let measures: Map<string, number>;
+    let counts: Map<number>;
+    let marks: Map<number>;
+    let measures: Map<number>;
 
     /**
      * Marks a performance event.
@@ -27,8 +27,8 @@ namespace ts.performance {
      */
     export function mark(markName: string) {
         if (enabled) {
-            marks.set(markName, timestamp());
-            counts.set(markName, (counts.get(markName) || 0) + 1);
+            marks[markName] = timestamp();
+            counts[markName] = (counts[markName] || 0) + 1;
             profilerEvent(markName);
         }
     }
@@ -44,9 +44,9 @@ namespace ts.performance {
      */
     export function measure(measureName: string, startMarkName?: string, endMarkName?: string) {
         if (enabled) {
-            const end = endMarkName && marks.get(endMarkName) || timestamp();
-            const start = startMarkName && marks.get(startMarkName) || profilerStart;
-            measures.set(measureName, (measures.get(measureName) || 0) + (end - start));
+            const end = endMarkName && marks[endMarkName] || timestamp();
+            const start = startMarkName && marks[startMarkName] || profilerStart;
+            measures[measureName] = (measures[measureName] || 0) + (end - start);
         }
     }
 
@@ -56,7 +56,7 @@ namespace ts.performance {
      * @param markName The name of the mark.
      */
     export function getCount(markName: string) {
-        return counts && counts.get(markName) || 0;
+        return counts && counts[markName] || 0;
     }
 
     /**
@@ -65,7 +65,7 @@ namespace ts.performance {
      * @param measureName The name of the measure whose durations should be accumulated.
      */
     export function getDuration(measureName: string) {
-        return measures && measures.get(measureName) || 0;
+        return measures && measures[measureName] || 0;
     }
 
     /**
@@ -74,14 +74,16 @@ namespace ts.performance {
      * @param cb The action to perform for each measure
      */
     export function forEachMeasure(cb: (measureName: string, duration: number) => void) {
-        measures.forEach((duration, measureName) => cb(measureName, duration));
+        for (const key in measures) {
+            cb(key, measures[key]);
+        }
     }
 
     /** Enables (and resets) performance measurements for the compiler. */
     export function enable() {
-        counts = createMap<string, number>();
-        marks = createMap<string, number>();
-        measures = createMap<string, number>();
+        counts = createMap<number>();
+        marks = createMap<number>();
+        measures = createMap<number>();
         enabled = true;
         profilerStart = timestamp();
     }
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 8a2b4d86671bf..532c90f38ec61 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -82,7 +82,7 @@ namespace ts {
     }
 
     export function createCompilerHost(options: CompilerOptions, setParentNodes?: boolean): CompilerHost {
-        const existingDirectories = createSet();
+        const existingDirectories = createMap<boolean>();
 
         function getCanonicalFileName(fileName: string): string {
             // if underlying system can distinguish between two files whose names differs only in cases then file name already in canonical form.
@@ -114,11 +114,11 @@ namespace ts {
         }
 
         function directoryExists(directoryPath: string): boolean {
-            if (existingDirectories.has(directoryPath)) {
+            if (directoryPath in existingDirectories) {
                 return true;
             }
             if (sys.directoryExists(directoryPath)) {
-                existingDirectories.add(directoryPath);
+                existingDirectories[directoryPath] = true;
                 return true;
             }
             return false;
@@ -132,21 +132,21 @@ namespace ts {
             }
         }
 
-        let outputFingerprints: Map<string, OutputFingerprint>;
+        let outputFingerprints: Map<OutputFingerprint>;
 
         function writeFileIfUpdated(fileName: string, data: string, writeByteOrderMark: boolean): void {
             if (!outputFingerprints) {
-                outputFingerprints = createMap<string, OutputFingerprint>();
+                outputFingerprints = createMap<OutputFingerprint>();
             }
 
             const hash = sys.createHash(data);
             const mtimeBefore = sys.getModifiedTime(fileName);
 
-            if (mtimeBefore) {
-                const fingerprint = outputFingerprints.get(fileName);
+            if (mtimeBefore && fileName in outputFingerprints) {
+                const fingerprint = outputFingerprints[fileName];
 
                 // If output has not been changed, and the file has no external modification
-                if (fingerprint && fingerprint.byteOrderMark === writeByteOrderMark &&
+                if (fingerprint.byteOrderMark === writeByteOrderMark &&
                     fingerprint.hash === hash &&
                     fingerprint.mtime.getTime() === mtimeBefore.getTime()) {
                     return;
@@ -157,11 +157,11 @@ namespace ts {
 
             const mtimeAfter = sys.getModifiedTime(fileName);
 
-            outputFingerprints.set(fileName, {
+            outputFingerprints[fileName] = {
                 hash,
                 byteOrderMark: writeByteOrderMark,
                 mtime: mtimeAfter
-            });
+            };
         }
 
         function writeFile(fileName: string, data: string, writeByteOrderMark: boolean, onError?: (message: string) => void) {
@@ -279,11 +279,11 @@ namespace ts {
             return [];
         }
         const resolutions: T[] = [];
-        const cache = createMap<string, T>();
+        const cache = createMap<T>();
         for (const name of names) {
-            const result = cache.has(name)
-                ? cache.get(name)
-                : setAndReturn(cache, name, loader(name, containingFile));
+            const result = name in cache
+                ? cache[name]
+                : cache[name] = loader(name, containingFile);
             resolutions.push(result);
         }
         return resolutions;
@@ -295,9 +295,9 @@ namespace ts {
         let commonSourceDirectory: string;
         let diagnosticsProducingTypeChecker: TypeChecker;
         let noDiagnosticsTypeChecker: TypeChecker;
-        let classifiableNames: Set<string>;
+        let classifiableNames: Map<string>;
 
-        let resolvedTypeReferenceDirectives = createMap<string, ResolvedTypeReferenceDirective>();
+        let resolvedTypeReferenceDirectives = createMap<ResolvedTypeReferenceDirective>();
         let fileProcessingDiagnostics = createDiagnosticCollection();
 
         // The below settings are to track if a .js file should be add to the program if loaded via searching under node_modules.
@@ -312,10 +312,10 @@ namespace ts {
 
         // If a module has some of its imports skipped due to being at the depth limit under node_modules, then track
         // this, as it may be imported at a shallower depth later, and then it will need its skipped imports processed.
-        const modulesWithElidedImports = createMap<string, boolean>();
+        const modulesWithElidedImports = createMap<boolean>();
 
         // Track source files that are source files found by searching under node_modules, as these shouldn't be compiled.
-        const sourceFilesFoundSearchingNodeModules = createMap<string, boolean>();
+        const sourceFilesFoundSearchingNodeModules = createMap<boolean>();
 
         performance.mark("beforeProgram");
 
@@ -448,11 +448,15 @@ namespace ts {
             return commonSourceDirectory;
         }
 
-        function getClassifiableNames(): Set<string> {
+        function getClassifiableNames() {
             if (!classifiableNames) {
                 // Initialize a checker so that all our files are bound.
                 getTypeChecker();
-                classifiableNames = setAggregate(files, sourceFile => sourceFile.classifiableNames);
+                classifiableNames = createMap<string>();
+
+                for (const sourceFile of files) {
+                    copyProperties(sourceFile.classifiableNames, classifiableNames);
+                }
             }
 
             return classifiableNames;
@@ -588,7 +592,7 @@ namespace ts {
                 getSourceFile: program.getSourceFile,
                 getSourceFileByPath: program.getSourceFileByPath,
                 getSourceFiles: program.getSourceFiles,
-                isSourceFileFromExternalLibrary: (file: SourceFile) => !!sourceFilesFoundSearchingNodeModules.get(file.path),
+                isSourceFileFromExternalLibrary: (file: SourceFile) => !!sourceFilesFoundSearchingNodeModules[file.path],
                 writeFile: writeFileCallback || (
                     (fileName, data, writeByteOrderMark, onError, sourceFiles) => host.writeFile(fileName, data, writeByteOrderMark, onError, sourceFiles)),
                 isEmitBlocked,
@@ -1128,8 +1132,8 @@ namespace ts {
 
         // Get source file from normalized fileName
         function findSourceFile(fileName: string, path: Path, isDefaultLib: boolean, refFile?: SourceFile, refPos?: number, refEnd?: number): SourceFile {
-            let file = filesByName.get(path);
-            if (file !== undefined) {
+            if (filesByName.contains(path)) {
+                const file = filesByName.get(path);
                 // try to check if we've already seen this file but with a different casing in path
                 // NOTE: this only makes sense for case-insensitive file systems
                 if (file && options.forceConsistentCasingInFileNames && getNormalizedAbsolutePath(file.fileName, currentDirectory) !== getNormalizedAbsolutePath(fileName, currentDirectory)) {
@@ -1138,20 +1142,20 @@ namespace ts {
 
                 // If the file was previously found via a node_modules search, but is now being processed as a root file,
                 // then everything it sucks in may also be marked incorrectly, and needs to be checked again.
-                if (file && sourceFilesFoundSearchingNodeModules.get(file.path) && currentNodeModulesDepth == 0) {
-                    sourceFilesFoundSearchingNodeModules.set(file.path, false);
+                if (file && sourceFilesFoundSearchingNodeModules[file.path] && currentNodeModulesDepth == 0) {
+                    sourceFilesFoundSearchingNodeModules[file.path] = false;
                     if (!options.noResolve) {
                         processReferencedFiles(file, isDefaultLib);
                         processTypeReferenceDirectives(file);
                     }
 
-                    modulesWithElidedImports.set(file.path, false);
+                    modulesWithElidedImports[file.path] = false;
                     processImportedModules(file);
                 }
                 // See if we need to reprocess the imports due to prior skipped imports
-                else if (file && modulesWithElidedImports.get(file.path)) {
+                else if (file && modulesWithElidedImports[file.path]) {
                     if (currentNodeModulesDepth < maxNodeModuleJsDepth) {
-                        modulesWithElidedImports.set(file.path, false);
+                        modulesWithElidedImports[file.path] = false;
                         processImportedModules(file);
                     }
                 }
@@ -1160,7 +1164,7 @@ namespace ts {
             }
 
             // We haven't looked for this file, do so now and cache result
-            file = host.getSourceFile(fileName, options.target, hostErrorMessage => {
+            const file = host.getSourceFile(fileName, options.target, hostErrorMessage => {
                 if (refFile !== undefined && refPos !== undefined && refEnd !== undefined) {
                     fileProcessingDiagnostics.add(createFileDiagnostic(refFile, refPos, refEnd - refPos,
                         Diagnostics.Cannot_read_file_0_Colon_1, fileName, hostErrorMessage));
@@ -1172,7 +1176,7 @@ namespace ts {
 
             filesByName.set(path, file);
             if (file) {
-                sourceFilesFoundSearchingNodeModules.set(path, currentNodeModulesDepth > 0);
+                sourceFilesFoundSearchingNodeModules[path] = (currentNodeModulesDepth > 0);
                 file.path = path;
 
                 if (host.useCaseSensitiveFileNames()) {
@@ -1233,7 +1237,7 @@ namespace ts {
             refFile?: SourceFile, refPos?: number, refEnd?: number): void {
 
             // If we already found this library as a primary reference - nothing to do
-            const previousResolution = resolvedTypeReferenceDirectives.get(typeReferenceDirective);
+            const previousResolution = resolvedTypeReferenceDirectives[typeReferenceDirective];
             if (previousResolution && previousResolution.primary) {
                 return;
             }
@@ -1270,7 +1274,7 @@ namespace ts {
             }
 
             if (saveResolution) {
-                resolvedTypeReferenceDirectives.set(typeReferenceDirective, resolvedTypeReferenceDirective);
+                resolvedTypeReferenceDirectives[typeReferenceDirective] = resolvedTypeReferenceDirective;
             }
         }
 
@@ -1290,7 +1294,7 @@ namespace ts {
         function processImportedModules(file: SourceFile) {
             collectExternalModuleReferences(file);
             if (file.imports.length || file.moduleAugmentations.length) {
-                file.resolvedModules = createMap<string, ResolvedModuleFull>();
+                file.resolvedModules = createMap<ResolvedModuleFull>();
                 const moduleNames = map(concatenate(file.imports, file.moduleAugmentations), getTextOfLiteral);
                 const resolutions = resolveModuleNamesWorker(moduleNames, getNormalizedAbsolutePath(file.fileName, currentDirectory));
                 Debug.assert(resolutions.length === moduleNames.length);
@@ -1321,7 +1325,7 @@ namespace ts {
                     const shouldAddFile = resolvedFileName && !getResolutionDiagnostic(options, resolution) && !options.noResolve && i < file.imports.length && !elideImport;
 
                     if (elideImport) {
-                        modulesWithElidedImports.set(file.path, true);
+                        modulesWithElidedImports[file.path] = true;
                     }
                     else if (shouldAddFile) {
                         const path = toPath(resolvedFileName, currentDirectory, getCanonicalFileName);
diff --git a/src/compiler/scanner.ts b/src/compiler/scanner.ts
index dec76d2b926b6..1c0baa457f4af 100644
--- a/src/compiler/scanner.ts
+++ b/src/compiler/scanner.ts
@@ -56,7 +56,7 @@ namespace ts {
         tryScan<T>(callback: () => T): T;
     }
 
-    const textToToken = mapOfMapLike({
+    const textToToken = createMap({
         "abstract": SyntaxKind.AbstractKeyword,
         "any": SyntaxKind.AnyKeyword,
         "as": SyntaxKind.AsKeyword,
@@ -272,11 +272,11 @@ namespace ts {
             lookupInUnicodeMap(code, unicodeES3IdentifierPart);
     }
 
-    function makeReverseMap(source: Map<string, number>): string[] {
+    function makeReverseMap(source: Map<number>): string[] {
         const result: string[] = [];
-        source.forEach((num, name) => {
-            result[num] = name;
-        });
+        for (const name in source) {
+            result[source[name]] = name;
+        }
         return result;
     }
 
@@ -288,7 +288,7 @@ namespace ts {
 
     /* @internal */
     export function stringToToken(s: string): SyntaxKind {
-        return textToToken.get(s);
+        return textToToken[s];
     }
 
     /* @internal */
@@ -362,6 +362,8 @@ namespace ts {
         return computeLineAndCharacterOfPosition(getLineStarts(sourceFile), position);
     }
 
+    const hasOwnProperty = Object.prototype.hasOwnProperty;
+
     export function isWhiteSpace(ch: number): boolean {
         return isWhiteSpaceSingleLine(ch) || isLineBreak(ch);
     }
@@ -1180,11 +1182,8 @@ namespace ts {
             const len = tokenValue.length;
             if (len >= 2 && len <= 11) {
                 const ch = tokenValue.charCodeAt(0);
-                if (ch >= CharacterCodes.a && ch <= CharacterCodes.z) {
-                    token = textToToken.get(tokenValue);
-                    if (token !== undefined) {
-                        return token;
-                    }
+                if (ch >= CharacterCodes.a && ch <= CharacterCodes.z && hasOwnProperty.call(textToToken, tokenValue)) {
+                    return token = textToToken[tokenValue];
                 }
             }
             return token = SyntaxKind.Identifier;
diff --git a/src/compiler/sourcemap.ts b/src/compiler/sourcemap.ts
index fcf85aa86a676..46db5188e339c 100644
--- a/src/compiler/sourcemap.ts
+++ b/src/compiler/sourcemap.ts
@@ -362,7 +362,7 @@ namespace ts {
 
             const emitNode = node && node.emitNode;
             const emitFlags = emitNode && emitNode.flags;
-            const range = emitNode && emitNode.tokenSourceMapRanges && emitNode.tokenSourceMapRanges.get(token);
+            const range = emitNode && emitNode.tokenSourceMapRanges && emitNode.tokenSourceMapRanges[token];
 
             tokenPos = skipTrivia(currentSourceText, range ? range.pos : tokenPos);
             if ((emitFlags & EmitFlags.NoTokenLeadingSourceMaps) === 0 && tokenPos >= 0) {
diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index 5df1976f98e34..13bbfc2ab153f 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -237,25 +237,25 @@ namespace ts {
             const useNonPollingWatchers = process.env["TSC_NONPOLLING_WATCHER"];
 
             function createWatchedFileSet() {
-                const dirWatchers = createMap<string, DirectoryWatcher>();
+                const dirWatchers = createMap<DirectoryWatcher>();
                 // One file can have multiple watchers
-                const fileWatcherCallbacks = createMap<string, FileWatcherCallback[]>();
+                const fileWatcherCallbacks = createMap<FileWatcherCallback[]>();
                 return { addFile, removeFile };
 
                 function reduceDirWatcherRefCountForFile(fileName: string) {
                     const dirName = getDirectoryPath(fileName);
-                    const watcher = dirWatchers.get(dirName);
+                    const watcher = dirWatchers[dirName];
                     if (watcher) {
                         watcher.referenceCount -= 1;
                         if (watcher.referenceCount <= 0) {
                             watcher.close();
-                            dirWatchers.delete(dirName);
+                            delete dirWatchers[dirName];
                         }
                     }
                 }
 
                 function addDirWatcher(dirPath: string): void {
-                    let watcher = dirWatchers.get(dirPath);
+                    let watcher = dirWatchers[dirPath];
                     if (watcher) {
                         watcher.referenceCount += 1;
                         return;
@@ -266,7 +266,7 @@ namespace ts {
                         (eventName: string, relativeFileName: string) => fileEventHandler(eventName, relativeFileName, dirPath)
                     );
                     watcher.referenceCount = 1;
-                    dirWatchers.set(dirPath, watcher);
+                    dirWatchers[dirPath] = watcher;
                     return;
                 }
 
@@ -296,12 +296,9 @@ namespace ts {
                         ? undefined
                         : ts.getNormalizedAbsolutePath(relativeFileName, baseDirPath);
                     // Some applications save a working file via rename operations
-                    if ((eventName === "change" || eventName === "rename")) {
-                        const callbacks = fileWatcherCallbacks.get(fileName);
-                        if (callbacks) {
-                            for (const fileCallback of callbacks) {
-                                fileCallback(fileName);
-                           }
+                    if ((eventName === "change" || eventName === "rename") && fileWatcherCallbacks[fileName]) {
+                        for (const fileCallback of fileWatcherCallbacks[fileName]) {
+                            fileCallback(fileName);
                         }
                     }
                 }
diff --git a/src/compiler/transformer.ts b/src/compiler/transformer.ts
index 4534564a854a4..ee9c081e6ebd8 100644
--- a/src/compiler/transformer.ts
+++ b/src/compiler/transformer.ts
@@ -12,14 +12,14 @@
 
 /* @internal */
 namespace ts {
-    const moduleTransformerMap = createMap<ModuleKind, Transformer>([
-        [ModuleKind.ES2015, transformES2015Module],
-        [ModuleKind.System, transformSystemModule],
-        [ModuleKind.AMD, transformModule],
-        [ModuleKind.CommonJS, transformModule],
-        [ModuleKind.UMD, transformModule],
-        [ModuleKind.None, transformModule],
-    ]);
+    const moduleTransformerMap = createMap<Transformer>({
+        [ModuleKind.ES2015]: transformES2015Module,
+        [ModuleKind.System]: transformSystemModule,
+        [ModuleKind.AMD]: transformModule,
+        [ModuleKind.CommonJS]: transformModule,
+        [ModuleKind.UMD]: transformModule,
+        [ModuleKind.None]: transformModule,
+    });
 
     const enum SyntaxKindFeatureFlags {
         Substitution = 1 << 0,
@@ -129,7 +129,7 @@ namespace ts {
             transformers.push(transformGenerators);
         }
 
-        transformers.push(moduleTransformerMap.get(moduleKind) || moduleTransformerMap.get(ModuleKind.None));
+        transformers.push(moduleTransformerMap[moduleKind] || moduleTransformerMap[ModuleKind.None]);
 
         // The ES5 transformer is last so that it can substitute expressions like `exports.default`
         // for ES3.
diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
index 4e0b0749d3a97..25c15305c4aa2 100644
--- a/src/compiler/transformers/es2015.ts
+++ b/src/compiler/transformers/es2015.ts
@@ -70,15 +70,15 @@ namespace ts {
          * set of labels that occurred inside the converted loop
          * used to determine if labeled jump can be emitted as is or it should be dispatched to calling code
          */
-        labels?: Map<string, string>;
+        labels?: Map<string>;
         /*
          * collection of labeled jumps that transfer control outside the converted loop.
          * maps store association 'label -> labelMarker' where
          * - label - value of label as it appear in code
          * - label marker - return value that should be interpreted by calling code as 'jump to <label>'
          */
-        labeledNonLocalBreaks?: Map<string, string>;
-        labeledNonLocalContinues?: Map<string, string>;
+        labeledNonLocalBreaks?: Map<string>;
+        labeledNonLocalContinues?: Map<string>;
 
         /*
          * set of non-labeled jumps that transfer control outside the converted loop
@@ -279,7 +279,7 @@ namespace ts {
             else if (node.transformFlags & TransformFlags.ContainsES2015 || (isInConstructorWithCapturedSuper && !isExpression(node))) {
                 // we want to dive in this branch either if node has children with ES2015 specific syntax
                 // or we are inside constructor that captures result of the super call so all returns without expression should be
-                // rewritten. Note: we skip expressions since returns should never appear there
+                // rewritten. Note: we skip expressions since returns should never appear there 
                 return visitEachChild(node, visitor, context);
             }
             else {
@@ -543,7 +543,7 @@ namespace ts {
                 //   - break/continue is non-labeled and located in non-converted loop/switch statement
                 const jump = node.kind === SyntaxKind.BreakStatement ? Jump.Break : Jump.Continue;
                 const canUseBreakOrContinue =
-                    (node.label && convertedLoopState.labels && convertedLoopState.labels.get(node.label.text)) ||
+                    (node.label && convertedLoopState.labels && convertedLoopState.labels[node.label.text]) ||
                     (!node.label && (convertedLoopState.allowedNonLabeledJumps & jump));
 
                 if (!canUseBreakOrContinue) {
@@ -1880,9 +1880,9 @@ namespace ts {
         function visitLabeledStatement(node: LabeledStatement): VisitResult<Statement> {
             if (convertedLoopState) {
                 if (!convertedLoopState.labels) {
-                    convertedLoopState.labels = createMap<string, string>();
+                    convertedLoopState.labels = createMap<string>();
                 }
-                convertedLoopState.labels.set(node.label.text, node.label.text);
+                convertedLoopState.labels[node.label.text] = node.label.text;
             }
 
             let result: VisitResult<Statement>;
@@ -1894,7 +1894,7 @@ namespace ts {
             }
 
             if (convertedLoopState) {
-                convertedLoopState.labels.set(node.label.text, undefined);
+                convertedLoopState.labels[node.label.text] = undefined;
             }
 
             return result;
@@ -2497,28 +2497,29 @@ namespace ts {
         function setLabeledJump(state: ConvertedLoopState, isBreak: boolean, labelText: string, labelMarker: string): void {
             if (isBreak) {
                 if (!state.labeledNonLocalBreaks) {
-                    state.labeledNonLocalBreaks = createMap<string, string>();
+                    state.labeledNonLocalBreaks = createMap<string>();
                 }
-                state.labeledNonLocalBreaks.set(labelText, labelMarker);
+                state.labeledNonLocalBreaks[labelText] = labelMarker;
             }
             else {
                 if (!state.labeledNonLocalContinues) {
-                    state.labeledNonLocalContinues = createMap<string, string>();
+                    state.labeledNonLocalContinues = createMap<string>();
                 }
-                state.labeledNonLocalContinues.set(labelText, labelMarker);
+                state.labeledNonLocalContinues[labelText] = labelMarker;
             }
         }
 
-        function processLabeledJumps(table: Map<string, string>, isBreak: boolean, loopResultName: Identifier, outerLoop: ConvertedLoopState, caseClauses: CaseClause[]): void {
+        function processLabeledJumps(table: Map<string>, isBreak: boolean, loopResultName: Identifier, outerLoop: ConvertedLoopState, caseClauses: CaseClause[]): void {
             if (!table) {
                 return;
             }
-            table.forEach((labelMarker, labelText) => {
+            for (const labelText in table) {
+                const labelMarker = table[labelText];
                 const statements: Statement[] = [];
                 // if there are no outer converted loop or outer label in question is located inside outer converted loop
                 // then emit labeled break\continue
                 // otherwise propagate pair 'label -> marker' to outer converted loop and emit 'return labelMarker' so outer loop can later decide what to do
-                if (!outerLoop || (outerLoop.labels && outerLoop.labels.get(labelText))) {
+                if (!outerLoop || (outerLoop.labels && outerLoop.labels[labelText])) {
                     const label = createIdentifier(labelText);
                     statements.push(isBreak ? createBreak(label) : createContinue(label));
                 }
@@ -2527,7 +2528,7 @@ namespace ts {
                     statements.push(createReturn(loopResultName));
                 }
                 caseClauses.push(createCaseClause(createLiteral(labelMarker), statements));
-            });
+            }
         }
 
         function processLoopVariableDeclaration(decl: VariableDeclaration | BindingElement, loopParameters: ParameterDeclaration[], loopOutParameters: LoopOutParameter[]) {
diff --git a/src/compiler/transformers/generators.ts b/src/compiler/transformers/generators.ts
index 74bc4ef4f0a56..7c9cde59fde74 100644
--- a/src/compiler/transformers/generators.ts
+++ b/src/compiler/transformers/generators.ts
@@ -217,13 +217,13 @@ namespace ts {
         Endfinally = 7,
     }
 
-    const instructionNames = createMap<Instruction, string>([
-        [Instruction.Return, "return"],
-        [Instruction.Break, "break"],
-        [Instruction.Yield, "yield"],
-        [Instruction.YieldStar, "yield*"],
-        [Instruction.Endfinally, "endfinally"],
-    ]);
+    const instructionNames = createMap<string>({
+        [Instruction.Return]: "return",
+        [Instruction.Break]: "break",
+        [Instruction.Yield]: "yield",
+        [Instruction.YieldStar]: "yield*",
+        [Instruction.Endfinally]: "endfinally",
+    });
 
     export function transformGenerators(context: TransformationContext) {
         const {
@@ -240,8 +240,8 @@ namespace ts {
         context.onSubstituteNode = onSubstituteNode;
 
         let currentSourceFile: SourceFile;
-        let renamedCatchVariables: Set<string>;
-        let renamedCatchVariableDeclarations: Map<number, Identifier>;
+        let renamedCatchVariables: Map<boolean>;
+        let renamedCatchVariableDeclarations: Map<Identifier>;
 
         let inGeneratorFunctionBody: boolean;
         let inStatementContainingYield: boolean;
@@ -1908,12 +1908,12 @@ namespace ts {
         }
 
         function substituteExpressionIdentifier(node: Identifier) {
-            if (renamedCatchVariables && renamedCatchVariables.has(node.text)) {
+            if (renamedCatchVariables && hasProperty(renamedCatchVariables, node.text)) {
                 const original = getOriginalNode(node);
                 if (isIdentifier(original) && original.parent) {
                     const declaration = resolver.getReferencedValueDeclaration(original);
                     if (declaration) {
-                        const name = renamedCatchVariableDeclarations.get(getOriginalNodeId(declaration));
+                        const name = getProperty(renamedCatchVariableDeclarations, String(getOriginalNodeId(declaration)));
                         if (name) {
                             const clone = getMutableClone(name);
                             setSourceMapRange(clone, node);
@@ -2078,13 +2078,13 @@ namespace ts {
             const name = declareLocal(text);
 
             if (!renamedCatchVariables) {
-                renamedCatchVariables = createSet();
-                renamedCatchVariableDeclarations = createMap<number, Identifier>();
+                renamedCatchVariables = createMap<boolean>();
+                renamedCatchVariableDeclarations = createMap<Identifier>();
                 context.enableSubstitution(SyntaxKind.Identifier);
             }
 
-            renamedCatchVariables.add(text);
-            renamedCatchVariableDeclarations.set(getOriginalNodeId(variable), name);
+            renamedCatchVariables[text] = true;
+            renamedCatchVariableDeclarations[getOriginalNodeId(variable)] = name;
 
             const exception = <ExceptionBlock>peekBlock();
             Debug.assert(exception.state < ExceptionBlockState.Catch);
@@ -2388,7 +2388,7 @@ namespace ts {
          */
         function createInstruction(instruction: Instruction): NumericLiteral {
             const literal = createLiteral(instruction);
-            literal.trailingComment = instructionNames.get(instruction);
+            literal.trailingComment = instructionNames[instruction];
             return literal;
         }
 
diff --git a/src/compiler/transformers/jsx.ts b/src/compiler/transformers/jsx.ts
index 5464325eb5b1e..95a4016bb0aeb 100644
--- a/src/compiler/transformers/jsx.ts
+++ b/src/compiler/transformers/jsx.ts
@@ -3,7 +3,7 @@
 
 /*@internal*/
 namespace ts {
-    const entities: Map<string, number> = createEntitiesMap();
+    const entities: Map<number> = createEntitiesMap();
 
     export function transformJsx(context: TransformationContext) {
         const compilerOptions = context.getCompilerOptions();
@@ -227,7 +227,7 @@ namespace ts {
                     return String.fromCharCode(parseInt(hex, 16));
                 }
                 else {
-                    const ch = entities.get(word);
+                    const ch = entities[word];
                     // If this is not a valid entity, then just use `match` (replace it with itself, i.e. don't replace)
                     return ch ? String.fromCharCode(ch) : match;
                 }
@@ -275,8 +275,8 @@ namespace ts {
         }
     }
 
-    function createEntitiesMap(): Map<string, number> {
-        return mapOfMapLike<number>({
+    function createEntitiesMap(): Map<number> {
+        return createMap<number>({
             "quot": 0x0022,
             "amp": 0x0026,
             "apos": 0x0027,
diff --git a/src/compiler/transformers/module/module.ts b/src/compiler/transformers/module/module.ts
index 11a2a3dccad96..87d02b4402548 100644
--- a/src/compiler/transformers/module/module.ts
+++ b/src/compiler/transformers/module/module.ts
@@ -10,12 +10,12 @@ namespace ts {
             importAliasNames: ParameterDeclaration[];
         }
 
-        const transformModuleDelegates = createMap<ModuleKind, (node: SourceFile) => SourceFile>([
-            [ModuleKind.None, transformCommonJSModule],
-            [ModuleKind.CommonJS, transformCommonJSModule],
-            [ModuleKind.AMD, transformAMDModule],
-            [ModuleKind.UMD, transformUMDModule],
-        ]);
+        const transformModuleDelegates = createMap<(node: SourceFile) => SourceFile>({
+            [ModuleKind.None]: transformCommonJSModule,
+            [ModuleKind.CommonJS]: transformCommonJSModule,
+            [ModuleKind.AMD]: transformAMDModule,
+            [ModuleKind.UMD]: transformUMDModule,
+        });
 
         const {
             startLexicalEnvironment,
@@ -32,7 +32,6 @@ namespace ts {
         const previousOnEmitNode = context.onEmitNode;
         context.onSubstituteNode = onSubstituteNode;
         context.onEmitNode = onEmitNode;
-
         context.enableSubstitution(SyntaxKind.Identifier); // Substitutes expression identifiers with imported/exported symbols.
         context.enableSubstitution(SyntaxKind.BinaryExpression); // Substitutes assignments to exported symbols.
         context.enableSubstitution(SyntaxKind.PrefixUnaryExpression); // Substitutes updates to exported symbols.
@@ -40,12 +39,12 @@ namespace ts {
         context.enableSubstitution(SyntaxKind.ShorthandPropertyAssignment); // Substitutes shorthand property assignments for imported/exported symbols.
         context.enableEmitNotification(SyntaxKind.SourceFile); // Restore state when substituting nodes in a file.
 
-        const moduleInfoMap = createMap<number, ExternalModuleInfo>(); // The ExternalModuleInfo for each file.
-        const deferredExports = createMap<number, Statement[]>(); // Exports to defer until an EndOfDeclarationMarker is found.
+        const moduleInfoMap = createMap<ExternalModuleInfo>(); // The ExternalModuleInfo for each file.
+        const deferredExports = createMap<Statement[]>(); // Exports to defer until an EndOfDeclarationMarker is found.
 
         let currentSourceFile: SourceFile; // The current file.
         let currentModuleInfo: ExternalModuleInfo; // The ExternalModuleInfo for the current file.
-        let noSubstitution: Map<number, boolean>; // Set of nodes for which substitution rules should be ignored.
+        let noSubstitution: Map<boolean>; // Set of nodes for which substitution rules should be ignored.
 
         return transformSourceFile;
 
@@ -62,10 +61,10 @@ namespace ts {
             }
 
             currentSourceFile = node;
-            currentModuleInfo = setAndReturn(moduleInfoMap, getOriginalNodeId(node), collectExternalModuleInfo(node, resolver));
+            currentModuleInfo = moduleInfoMap[getOriginalNodeId(node)] = collectExternalModuleInfo(node, resolver);
 
             // Perform the transformation.
-            const transformModule = transformModuleDelegates.get(moduleKind) || transformModuleDelegates.get(ModuleKind.None);
+            const transformModule = transformModuleDelegates[moduleKind] || transformModuleDelegates[ModuleKind.None];
             const updated = transformModule(node);
 
             currentSourceFile = undefined;
@@ -445,7 +444,7 @@ namespace ts {
             if (hasAssociatedEndOfDeclarationMarker(node)) {
                 // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportsOfImportDeclaration(deferredExports.get(id), node));
+                deferredExports[id] = appendExportsOfImportDeclaration(deferredExports[id], node);
             }
             else {
                 statements = appendExportsOfImportDeclaration(statements, node);
@@ -524,7 +523,7 @@ namespace ts {
             if (hasAssociatedEndOfDeclarationMarker(node)) {
                 // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportsOfImportEqualsDeclaration(deferredExports.get(id), node));
+                deferredExports[id] = appendExportsOfImportEqualsDeclaration(deferredExports[id], node);
             }
             else {
                 statements = appendExportsOfImportEqualsDeclaration(statements, node);
@@ -611,7 +610,7 @@ namespace ts {
             if (original && hasAssociatedEndOfDeclarationMarker(original)) {
                 // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportStatement(deferredExports.get(id), createIdentifier("default"), node.expression, /*location*/ node, /*allowComments*/ true));
+                deferredExports[id] = appendExportStatement(deferredExports[id], createIdentifier("default"), node.expression, /*location*/ node, /*allowComments*/ true);
             }
             else {
                 statements = appendExportStatement(statements, createIdentifier("default"), node.expression, /*location*/ node, /*allowComments*/ true);
@@ -652,7 +651,7 @@ namespace ts {
             if (hasAssociatedEndOfDeclarationMarker(node)) {
                 // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportsOfHoistedDeclaration(deferredExports.get(id), node));
+                deferredExports[id] = appendExportsOfHoistedDeclaration(deferredExports[id], node);
             }
             else {
                 statements = appendExportsOfHoistedDeclaration(statements, node);
@@ -691,7 +690,7 @@ namespace ts {
             if (hasAssociatedEndOfDeclarationMarker(node)) {
                 // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportsOfHoistedDeclaration(deferredExports.get(id), node));
+                deferredExports[id] = appendExportsOfHoistedDeclaration(deferredExports[id], node);
             }
             else {
                 statements = appendExportsOfHoistedDeclaration(statements, node);
@@ -742,7 +741,7 @@ namespace ts {
             if (hasAssociatedEndOfDeclarationMarker(node)) {
                 // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportsOfVariableStatement(deferredExports.get(id), node));
+                deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], node);
             }
             else {
                 statements = appendExportsOfVariableStatement(statements, node);
@@ -792,7 +791,7 @@ namespace ts {
             // statement.
             if (hasAssociatedEndOfDeclarationMarker(node) && node.original.kind === SyntaxKind.VariableStatement) {
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportsOfVariableStatement(deferredExports.get(id), <VariableStatement>node.original));
+                deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], <VariableStatement>node.original);
             }
 
             return node;
@@ -818,9 +817,9 @@ namespace ts {
             // end of the transformed declaration. We use this marker to emit any deferred exports
             // of the declaration.
             const id = getOriginalNodeId(node);
-            const statements = deferredExports.get(id);
+            const statements = deferredExports[id];
             if (statements) {
-                deferredExports.delete(id);
+                delete deferredExports[id];
                 return append(statements, node);
             }
 
@@ -971,7 +970,7 @@ namespace ts {
          */
         function appendExportsOfDeclaration(statements: Statement[] | undefined, decl: Declaration): Statement[] | undefined {
             const name = getDeclarationName(decl);
-            const exportSpecifiers = currentModuleInfo.exportSpecifiers.get(name.text);
+            const exportSpecifiers = currentModuleInfo.exportSpecifiers[name.text];
             if (exportSpecifiers) {
                 for (const exportSpecifier of exportSpecifiers) {
                     statements = appendExportStatement(statements, exportSpecifier.name, name, /*location*/ exportSpecifier.name);
@@ -995,7 +994,7 @@ namespace ts {
         function appendExportStatement(statements: Statement[] | undefined, exportName: Identifier, expression: Expression, location?: TextRange, allowComments?: boolean): Statement[] | undefined {
             if (exportName.text === "default") {
                 const sourceFile = getOriginalNode(currentSourceFile, isSourceFile);
-                if (sourceFile && !sourceFile.symbol.exports.get("___esModule")) {
+                if (sourceFile && !sourceFile.symbol.exports["___esModule"]) {
                     if (languageVersion === ScriptTarget.ES3) {
                         statements = append(statements,
                             createStatement(
@@ -1100,8 +1099,8 @@ namespace ts {
         function onEmitNode(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void {
             if (node.kind === SyntaxKind.SourceFile) {
                 currentSourceFile = <SourceFile>node;
-                currentModuleInfo = moduleInfoMap.get(getOriginalNodeId(currentSourceFile));
-                noSubstitution = createMap<number, boolean>();
+                currentModuleInfo = moduleInfoMap[getOriginalNodeId(currentSourceFile)];
+                noSubstitution = createMap<boolean>();
 
                 previousOnEmitNode(emitContext, node, emitCallback);
 
@@ -1126,7 +1125,7 @@ namespace ts {
          */
         function onSubstituteNode(emitContext: EmitContext, node: Node) {
             node = previousOnSubstituteNode(emitContext, node);
-            if (node.id && noSubstitution.get(node.id)) {
+            if (node.id && noSubstitution[node.id]) {
                 return node;
             }
 
@@ -1244,7 +1243,7 @@ namespace ts {
                     let expression: Expression = node;
                     for (const exportName of exportedNames) {
                         // Mark the node to prevent triggering this rule again.
-                        noSubstitution.set(getNodeId(expression), true);
+                        noSubstitution[getNodeId(expression)] = true;
                         expression = createExportExpression(exportName, expression, /*location*/ node);
                     }
 
@@ -1286,7 +1285,7 @@ namespace ts {
                         : node;
                     for (const exportName of exportedNames) {
                         // Mark the node to prevent triggering this rule again.
-                        noSubstitution.set(getNodeId(expression), true);
+                        noSubstitution[getNodeId(expression)] = true;
                         expression = createExportExpression(exportName, expression);
                     }
 
@@ -1308,7 +1307,7 @@ namespace ts {
                     || resolver.getReferencedValueDeclaration(name);
                 if (valueDeclaration) {
                     return currentModuleInfo
-                        && currentModuleInfo.exportedBindings.get(getOriginalNodeId(valueDeclaration));
+                        && currentModuleInfo.exportedBindings[getOriginalNodeId(valueDeclaration)];
                 }
             }
         }
diff --git a/src/compiler/transformers/module/system.ts b/src/compiler/transformers/module/system.ts
index f3db63287b238..adc9385935b0b 100644
--- a/src/compiler/transformers/module/system.ts
+++ b/src/compiler/transformers/module/system.ts
@@ -28,10 +28,10 @@ namespace ts {
         context.enableSubstitution(SyntaxKind.PostfixUnaryExpression); // Substitutes updates to exported symbols.
         context.enableEmitNotification(SyntaxKind.SourceFile); // Restore state when substituting nodes in a file.
 
-        const moduleInfoMap = createMap<number, ExternalModuleInfo>(); // The ExternalModuleInfo for each file.
-        const deferredExports = createMap<number, Statement[]>(); // Exports to defer until an EndOfDeclarationMarker is found.
-        const exportFunctionsMap = createMap<number, Identifier>(); // The export function associated with a source file.
-        const noSubstitutionMap = createMap<number, Map<number, boolean>>(); // Set of nodes for which substitution rules should be ignored for each file.
+        const moduleInfoMap = createMap<ExternalModuleInfo>(); // The ExternalModuleInfo for each file.
+        const deferredExports = createMap<Statement[]>(); // Exports to defer until an EndOfDeclarationMarker is found.
+        const exportFunctionsMap = createMap<Identifier>(); // The export function associated with a source file.
+        const noSubstitutionMap = createMap<Map<boolean>>(); // Set of nodes for which substitution rules should be ignored for each file.
 
         let currentSourceFile: SourceFile; // The current file.
         let moduleInfo: ExternalModuleInfo; // ExternalModuleInfo for the current file.
@@ -39,7 +39,7 @@ namespace ts {
         let contextObject: Identifier; // The context object for the current file.
         let hoistedStatements: Statement[];
         let enclosingBlockScopedContainer: Node;
-        let noSubstitution: Map<number, boolean>; // Set of nodes for which substitution rules should be ignored.
+        let noSubstitution: Map<boolean>; // Set of nodes for which substitution rules should be ignored.
 
         return transformSourceFile;
 
@@ -73,11 +73,11 @@ namespace ts {
             // see comment to 'substitutePostfixUnaryExpression' for more details
 
             // Collect information about the external module and dependency groups.
-            moduleInfo = setAndReturn(moduleInfoMap, id, collectExternalModuleInfo(node, resolver));
+            moduleInfo = moduleInfoMap[id] = collectExternalModuleInfo(node, resolver);
 
             // Make sure that the name of the 'exports' function does not conflict with
             // existing identifiers.
-            exportFunction = setAndReturn(exportFunctionsMap, id, createUniqueName("exports"));
+            exportFunction = exportFunctionsMap[id] = createUniqueName("exports");
             contextObject = createUniqueName("context");
 
             // Add the body of the module.
@@ -118,7 +118,7 @@ namespace ts {
             setEmitFlags(updated, getEmitFlags(node) & ~EmitFlags.EmitEmitHelpers);
 
             if (noSubstitution) {
-                noSubstitutionMap.set(id, noSubstitution);
+                noSubstitutionMap[id] = noSubstitution;
                 noSubstitution = undefined;
             }
 
@@ -138,19 +138,19 @@ namespace ts {
          * @param externalImports The imports for the file.
          */
         function collectDependencyGroups(externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[]) {
-            const groupIndices = createMap<string, number>();
+            const groupIndices = createMap<number>();
             const dependencyGroups: DependencyGroup[] = [];
             for (let i = 0; i < externalImports.length; i++) {
                 const externalImport = externalImports[i];
                 const externalModuleName = getExternalModuleNameLiteral(externalImport, currentSourceFile, host, resolver, compilerOptions);
                 const text = externalModuleName.text;
-                const groupIndex = groupIndices.get(text);
-                if (groupIndex !== undefined) {
+                if (hasProperty(groupIndices, text)) {
                     // deduplicate/group entries in dependency list by the dependency name
+                    const groupIndex = groupIndices[text];
                     dependencyGroups[groupIndex].externalImports.push(externalImport);
                 }
                 else {
-                    groupIndices.set(text, dependencyGroups.length);
+                    groupIndices[text] = dependencyGroups.length;
                     dependencyGroups.push({
                         name: externalModuleName,
                         externalImports: [externalImport]
@@ -301,8 +301,7 @@ namespace ts {
             // this set is used to filter names brought by star expors.
 
             // local names set should only be added if we have anything exported
-
-            if (!moduleInfo.exportedNames && mapIsEmpty(moduleInfo.exportSpecifiers)) {
+            if (!moduleInfo.exportedNames && isEmpty(moduleInfo.exportSpecifiers)) {
                 // no exported declarations (export var ...) or export specifiers (export {x})
                 // check if we have any non star export declarations.
                 let hasExportDeclarationWithExportClause = false;
@@ -599,7 +598,7 @@ namespace ts {
             if (hasAssociatedEndOfDeclarationMarker(node)) {
                 // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportsOfImportDeclaration(deferredExports.get(id), node));
+                deferredExports[id] = appendExportsOfImportDeclaration(deferredExports[id], node);
             }
             else {
                 statements = appendExportsOfImportDeclaration(statements, node);
@@ -622,7 +621,7 @@ namespace ts {
             if (hasAssociatedEndOfDeclarationMarker(node)) {
                 // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportsOfImportEqualsDeclaration(deferredExports.get(id), node));
+                deferredExports[id] = appendExportsOfImportEqualsDeclaration(deferredExports[id], node);
             }
             else {
                 statements = appendExportsOfImportEqualsDeclaration(statements, node);
@@ -647,7 +646,7 @@ namespace ts {
             if (original && hasAssociatedEndOfDeclarationMarker(original)) {
                 // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportStatement(deferredExports.get(id), createIdentifier("default"), expression, /*allowComments*/ true));
+                deferredExports[id] = appendExportStatement(deferredExports[id], createIdentifier("default"), expression, /*allowComments*/ true);
             }
             else {
                 return createExportStatement(createIdentifier("default"), expression, /*allowComments*/ true);
@@ -679,7 +678,7 @@ namespace ts {
             if (hasAssociatedEndOfDeclarationMarker(node)) {
                 // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportsOfHoistedDeclaration(deferredExports.get(id), node));
+                deferredExports[id] = appendExportsOfHoistedDeclaration(deferredExports[id], node);
             }
             else {
                 hoistedStatements = appendExportsOfHoistedDeclaration(hoistedStatements, node);
@@ -721,7 +720,7 @@ namespace ts {
             if (hasAssociatedEndOfDeclarationMarker(node)) {
                 // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportsOfHoistedDeclaration(deferredExports.get(id), node));
+                deferredExports[id] = appendExportsOfHoistedDeclaration(deferredExports[id], node);
             }
             else {
                 statements = appendExportsOfHoistedDeclaration(statements, node);
@@ -761,7 +760,7 @@ namespace ts {
             if (isMarkedDeclaration) {
                 // Defer exports until we encounter an EndOfDeclarationMarker node
                 const id = getOriginalNodeId(node);
-                deferredExports.set(id, appendExportsOfVariableStatement(deferredExports.get(id), node, isExportedDeclaration));
+                deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], node, isExportedDeclaration);
             }
             else {
                 statements = appendExportsOfVariableStatement(statements, node, /*exportSelf*/ false);
@@ -867,7 +866,7 @@ namespace ts {
             if (hasAssociatedEndOfDeclarationMarker(node) && node.original.kind === SyntaxKind.VariableStatement) {
                 const id = getOriginalNodeId(node);
                 const isExportedDeclaration = hasModifier(node.original, ModifierFlags.Export);
-                deferredExports.set(id, appendExportsOfVariableStatement(deferredExports.get(id), <VariableStatement>node.original, isExportedDeclaration));
+                deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], <VariableStatement>node.original, isExportedDeclaration);
             }
 
             return node;
@@ -893,9 +892,9 @@ namespace ts {
             // end of the transformed declaration. We use this marker to emit any deferred exports
             // of the declaration.
             const id = getOriginalNodeId(node);
-            const statements = deferredExports.get(id);
+            const statements = deferredExports[id];
             if (statements) {
-                deferredExports.delete(id);
+                delete deferredExports[id];
                 return append(statements, node);
             }
 
@@ -1064,7 +1063,7 @@ namespace ts {
             }
 
             const name = getDeclarationName(decl);
-            const exportSpecifiers = moduleInfo.exportSpecifiers.get(name.text);
+            const exportSpecifiers = moduleInfo.exportSpecifiers[name.text];
             if (exportSpecifiers) {
                 for (const exportSpecifier of exportSpecifiers) {
                     if (exportSpecifier.name.text !== excludeName) {
@@ -1532,12 +1531,12 @@ namespace ts {
             if (node.kind === SyntaxKind.SourceFile) {
                 const id = getOriginalNodeId(node);
                 currentSourceFile = <SourceFile>node;
-                moduleInfo = moduleInfoMap.get(id);
-                exportFunction = exportFunctionsMap.get(id);
-                noSubstitution = noSubstitutionMap.get(id);
+                moduleInfo = moduleInfoMap[id];
+                exportFunction = exportFunctionsMap[id];
+                noSubstitution = noSubstitutionMap[id];
 
                 if (noSubstitution) {
-                    noSubstitutionMap.delete(id);
+                    delete noSubstitutionMap[id];
                 }
 
                 previousOnEmitNode(emitContext, node, emitCallback);
@@ -1726,7 +1725,7 @@ namespace ts {
                         exportedNames = append(exportedNames, getDeclarationName(valueDeclaration));
                     }
 
-                    exportedNames = addRange(exportedNames, moduleInfo && moduleInfo.exportedBindings.get(getOriginalNodeId(valueDeclaration)));
+                    exportedNames = addRange(exportedNames, moduleInfo && moduleInfo.exportedBindings[getOriginalNodeId(valueDeclaration)]);
                 }
             }
 
@@ -1739,8 +1738,8 @@ namespace ts {
          * @param node The node which should not be substituted.
          */
         function preventSubstitution<T extends Node>(node: T): T {
-            if (noSubstitution === undefined) noSubstitution = createMap<number, boolean>();
-            noSubstitution.set(getNodeId(node), true);
+            if (noSubstitution === undefined) noSubstitution = createMap<boolean>();
+            noSubstitution[getNodeId(node)] = true;
             return node;
         }
 
@@ -1750,7 +1749,7 @@ namespace ts {
          * @param node The node to test.
          */
         function isSubstitutionPrevented(node: Node) {
-            return noSubstitution && node.id && noSubstitution.get(node.id);
+            return noSubstitution && node.id && noSubstitution[node.id];
         }
     }
 }
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 3e9a9855f7e7a..fe264876b2581 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -47,7 +47,7 @@ namespace ts {
         let currentNamespace: ModuleDeclaration;
         let currentNamespaceContainerName: Identifier;
         let currentScope: SourceFile | Block | ModuleBlock | CaseBlock;
-        let currentScopeFirstDeclarationsOfName: Map<string, Node>;
+        let currentScopeFirstDeclarationsOfName: Map<Node>;
         let currentExternalHelpersModuleName: Identifier;
 
         /**
@@ -60,7 +60,7 @@ namespace ts {
          * A map that keeps track of aliases created for classes with decorators to avoid issues
          * with the double-binding behavior of classes.
          */
-        let classAliases: Map<number, Identifier>;
+        let classAliases: Map<Identifier>;
 
         /**
          * Keeps track of whether  we are within any containing namespaces when performing
@@ -783,7 +783,7 @@ namespace ts {
                 if (resolver.getNodeCheckFlags(node) & NodeCheckFlags.ClassWithConstructorReference) {
                     // record an alias as the class name is not in scope for statics.
                     enableSubstitutionForClassAliases();
-                    classAliases.set(getOriginalNodeId(node), getSynthesizedClone(temp));
+                    classAliases[getOriginalNodeId(node)] = getSynthesizedClone(temp);
                 }
 
                 // To preserve the behavior of the old emitter, we explicitly indent
@@ -1454,7 +1454,7 @@ namespace ts {
                 return undefined;
             }
 
-            const classAlias = classAliases && classAliases.get(getOriginalNodeId(node));
+            const classAlias = classAliases && classAliases[getOriginalNodeId(node)];
             const localName = getLocalName(node, /*allowComments*/ false, /*allowSourceMaps*/ true);
             const decorate = createDecorateHelper(currentExternalHelpersModuleName, decoratorExpressions, localName);
             const expression = createAssignment(localName, classAlias ? createAssignment(classAlias, decorate) : decorate);
@@ -2245,7 +2245,7 @@ namespace ts {
             const savedCurrentScope = currentScope;
             const savedCurrentScopeFirstDeclarationsOfName = currentScopeFirstDeclarationsOfName;
             currentScope = body;
-            currentScopeFirstDeclarationsOfName = createMap<string, Node>();
+            currentScopeFirstDeclarationsOfName = createMap<Node>();
             startLexicalEnvironment();
 
             const statements = visitNodes(body.statements, visitor, isStatement, start);
@@ -2630,10 +2630,12 @@ namespace ts {
             const name = node.symbol && node.symbol.name;
             if (name) {
                 if (!currentScopeFirstDeclarationsOfName) {
-                    currentScopeFirstDeclarationsOfName = createMap<string, Node>();
+                    currentScopeFirstDeclarationsOfName = createMap<Node>();
                 }
 
-                setIfNotSet(currentScopeFirstDeclarationsOfName, name, node);
+                if (!(name in currentScopeFirstDeclarationsOfName)) {
+                    currentScopeFirstDeclarationsOfName[name] = node;
+                }
             }
         }
 
@@ -2645,7 +2647,7 @@ namespace ts {
             if (currentScopeFirstDeclarationsOfName) {
                 const name = node.symbol && node.symbol.name;
                 if (name) {
-                    return currentScopeFirstDeclarationsOfName.get(name) === node;
+                    return currentScopeFirstDeclarationsOfName[name] === node;
                 }
             }
 
@@ -3186,7 +3188,7 @@ namespace ts {
             if (resolver.getNodeCheckFlags(node) & NodeCheckFlags.ClassWithConstructorReference) {
                 enableSubstitutionForClassAliases();
                 const classAlias = createUniqueName(node.name && !isGeneratedIdentifier(node.name) ? node.name.text : "default");
-                classAliases.set(getOriginalNodeId(node), classAlias);
+                classAliases[getOriginalNodeId(node)] = classAlias;
                 hoistVariableDeclaration(classAlias);
                 return classAlias;
             }
@@ -3218,7 +3220,7 @@ namespace ts {
                 context.enableSubstitution(SyntaxKind.Identifier);
 
                 // Keep track of class aliases.
-                classAliases = createMap<number, Identifier>();
+                classAliases = createMap<Identifier>();
             }
         }
 
@@ -3331,7 +3333,7 @@ namespace ts {
                     // constructor references in static property initializers.
                     const declaration = resolver.getReferencedValueDeclaration(node);
                     if (declaration) {
-                        const classAlias = classAliases.get(declaration.id);
+                        const classAlias = classAliases[declaration.id];
                         if (classAlias) {
                             const clone = getSynthesizedClone(classAlias);
                             setSourceMapRange(clone, node);
diff --git a/src/compiler/tsc.ts b/src/compiler/tsc.ts
index 28b3b9f3068b9..10d4a0c1d3679 100644
--- a/src/compiler/tsc.ts
+++ b/src/compiler/tsc.ts
@@ -93,7 +93,7 @@ namespace ts {
             return false;
         }
         try {
-            ts.localizedDiagnosticMessages = mapOfMapLike<string>(JSON.parse(fileContents));
+            ts.localizedDiagnosticMessages = JSON.parse(fileContents);
         }
         catch (e) {
             errors.push(createCompilerDiagnostic(Diagnostics.Corrupted_locale_file_0, filePath));
@@ -127,11 +127,11 @@ namespace ts {
     const gutterSeparator = " ";
     const resetEscapeSequence = "\u001b[0m";
     const ellipsis = "...";
-    const categoryFormatMap = createMap<DiagnosticCategory, string>([
-        [DiagnosticCategory.Warning, yellowForegroundEscapeSequence],
-        [DiagnosticCategory.Error, redForegroundEscapeSequence],
-        [DiagnosticCategory.Message, blueForegroundEscapeSequence],
-    ]);
+    const categoryFormatMap = createMap<string>({
+        [DiagnosticCategory.Warning]: yellowForegroundEscapeSequence,
+        [DiagnosticCategory.Error]: redForegroundEscapeSequence,
+        [DiagnosticCategory.Message]: blueForegroundEscapeSequence,
+    });
 
     function formatAndReset(text: string, formatStyle: string) {
         return formatStyle + text + resetEscapeSequence;
@@ -199,7 +199,7 @@ namespace ts {
             output += `${ relativeFileName }(${ firstLine + 1 },${ firstLineChar + 1 }): `;
         }
 
-        const categoryColor = categoryFormatMap.get(diagnostic.category);
+        const categoryColor = categoryFormatMap[diagnostic.category];
         const category = DiagnosticCategory[diagnostic.category].toLowerCase();
         output += `${ formatAndReset(category, categoryColor) } TS${ diagnostic.code }: ${ flattenDiagnosticMessageText(diagnostic.messageText, sys.newLine) }`;
         output += sys.newLine + sys.newLine;
@@ -255,7 +255,7 @@ namespace ts {
 
         // This map stores and reuses results of fileExists check that happen inside 'createProgram'
         // This allows to save time in module resolution heavy scenarios when existence of the same file might be checked multiple times.
-        let cachedExistingFiles: Map<string, boolean>;
+        let cachedExistingFiles: Map<boolean>;
         let hostFileExists: typeof compilerHost.fileExists;
 
         if (commandLine.options.locale) {
@@ -425,7 +425,7 @@ namespace ts {
             }
 
             // reset the cache of existing files
-            cachedExistingFiles = createMap<string, boolean>();
+            cachedExistingFiles = createMap<boolean>();
 
             const compileResult = compile(rootFileNames, compilerOptions, compilerHost);
 
@@ -438,7 +438,9 @@ namespace ts {
         }
 
         function cachedFileExists(fileName: string): boolean {
-            return getOrUpdate(cachedExistingFiles, fileName, hostFileExists);
+            return fileName in cachedExistingFiles
+                ? cachedExistingFiles[fileName]
+                : cachedExistingFiles[fileName] = hostFileExists(fileName);
         }
 
         function getSourceFile(fileName: string, languageVersion: ScriptTarget, onError?: (message: string) => void) {
@@ -706,7 +708,7 @@ namespace ts {
         const usageColumn: string[] = []; // Things like "-d, --declaration" go in here.
         const descriptionColumn: string[] = [];
 
-        const optionsDescriptionMap = createMap<string, string[]>();  // Map between option.description and list of option.type if it is a kind
+        const optionsDescriptionMap = createMap<string[]>();  // Map between option.description and list of option.type if it is a kind
 
         for (let i = 0; i < optsList.length; i++) {
             const option = optsList[i];
@@ -734,11 +736,11 @@ namespace ts {
                 description = getDiagnosticText(option.description);
                 const options: string[] = [];
                 const element = (<CommandLineOptionOfListType>option).element;
-                const typeMap = <Map<string, number | string>>element.type;
-                forEachKeyInMap(typeMap, key => {
+                const typeMap = <Map<number | string>>element.type;
+                for (const key in typeMap) {
                     options.push(`'${key}'`);
-                });
-                optionsDescriptionMap.set(description, options);
+                }
+                optionsDescriptionMap[description] = options;
             }
             else {
                 description = getDiagnosticText(option.description);
@@ -760,7 +762,7 @@ namespace ts {
         for (let i = 0; i < usageColumn.length; i++) {
             const usage = usageColumn[i];
             const description = descriptionColumn[i];
-            const kindsList = optionsDescriptionMap.get(description);
+            const kindsList = optionsDescriptionMap[description];
             output.push(usage + makePadding(marginLength - usage.length + 2) + description + sys.newLine);
 
             if (kindsList) {
diff --git a/src/compiler/tsconfig.json b/src/compiler/tsconfig.json
index d048ec2f891a6..f63bdf20e341e 100644
--- a/src/compiler/tsconfig.json
+++ b/src/compiler/tsconfig.json
@@ -15,7 +15,6 @@
     },
     "files": [
         "core.ts",
-        "collections.ts",
         "performance.ts",
         "sys.ts",
         "types.ts",
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 12f46751f6414..419d062bb7f9e 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -1,46 +1,11 @@
 namespace ts {
-    /**
-     * Type of objects whose values are all of the same type.
-     * The `in` and `for-in` operators can *not* be safely used,
-     * since `Object.prototype` may be modified by outside code.
-    */
+
     export interface MapLike<T> {
         [index: string]: T;
     }
 
-    /**
-     * This contains just the parts of ES6's `Map` interface that we allow.
-     * Map can only be instantiated using NumberMap and StringMap, which come with shims.
-     *
-     * Internet Explorer does not support iterator-returning methods, so those are not allowed here.
-     * But map-using functions in collections.ts check for these features and use them where possible.
-     */
-    export interface Map<K, V> {
-        clear(): void;
-        delete(key: K): boolean;
-        /**
-         * Call `action` for each entry in the map.
-         * Since we use a `for-in` loop for our shims, `key` may be a string.
-         */
-        forEach(action: (value: V, key: K | string) => void): void;
-        get(key: K): V;
-        /**
-         * Whether the key is in the map.
-         * Note: It is better to ask forgiveness than permission. Consider calling `get` and checking if the result is undefined.
-         */
-        has(key: K): boolean;
-        set(key: K, value: V): void;
-    }
-
-    /**
-     * This contains just the parts of ES6's `Set` interface that we allow.
-     */
-    export interface Set<T> {
-        add(value: T): void;
-        clear(): void;
-        delete(value: T): boolean;
-        forEach(action: (value: T) => void): void;
-        has(value: T): boolean;
+    export interface Map<T> extends MapLike<T> {
+        __mapBrand: any;
     }
 
     // branded string type used to store absolute, normalized and canonicalized paths
@@ -2079,7 +2044,7 @@ namespace ts {
 
         // this map is used by transpiler to supply alternative names for dependencies (i.e. in case of bundling)
         /* @internal */
-        renamedDependencies?: Map<string, string>;
+        renamedDependencies?: Map<string>;
 
         /**
          * lib.d.ts should have a reference comment like
@@ -2099,7 +2064,7 @@ namespace ts {
         // The first node that causes this file to be a CommonJS module
         /* @internal */ commonJsModuleIndicator: Node;
 
-        /* @internal */ identifiers: Map<string, string>;
+        /* @internal */ identifiers: Map<string>;
         /* @internal */ nodeCount: number;
         /* @internal */ identifierCount: number;
         /* @internal */ symbolCount: number;
@@ -2114,12 +2079,12 @@ namespace ts {
         // Stores a line map for the file.
         // This field should never be used directly to obtain line map, use getLineMap function instead.
         /* @internal */ lineMap: number[];
-        /* @internal */ classifiableNames?: Set<string>;
+        /* @internal */ classifiableNames?: Map<string>;
         // Stores a mapping 'external module reference text' -> 'resolved file name' | undefined
         // It is used to resolve module names in the checker.
         // Content of this field should never be used directly - use getResolvedModuleFileName/setResolvedModuleFileName functions instead
-        /* @internal */ resolvedModules: Map<string, ResolvedModuleFull>;
-        /* @internal */ resolvedTypeReferenceDirectiveNames: Map<string, ResolvedTypeReferenceDirective>;
+        /* @internal */ resolvedModules: Map<ResolvedModuleFull>;
+        /* @internal */ resolvedTypeReferenceDirectiveNames: Map<ResolvedTypeReferenceDirective>;
         /* @internal */ imports: LiteralExpression[];
         /* @internal */ moduleAugmentations: LiteralExpression[];
         /* @internal */ patternAmbientModules?: PatternAmbientModule[];
@@ -2203,7 +2168,7 @@ namespace ts {
         /* @internal */ getDiagnosticsProducingTypeChecker(): TypeChecker;
         /* @internal */ dropDiagnosticsProducingTypeChecker(): void;
 
-        /* @internal */ getClassifiableNames(): Set<string>;
+        /* @internal */ getClassifiableNames(): Map<string>;
 
         /* @internal */ getNodeCount(): number;
         /* @internal */ getIdentifierCount(): number;
@@ -2211,7 +2176,7 @@ namespace ts {
         /* @internal */ getTypeCount(): number;
 
         /* @internal */ getFileProcessingDiagnostics(): DiagnosticCollection;
-        /* @internal */ getResolvedTypeReferenceDirectives(): Map<string, ResolvedTypeReferenceDirective>;
+        /* @internal */ getResolvedTypeReferenceDirectives(): Map<ResolvedTypeReferenceDirective>;
         // For testing purposes only.
         /* @internal */ structureIsReused?: boolean;
     }
@@ -2272,7 +2237,7 @@ namespace ts {
 
         getSourceFiles(): SourceFile[];
         getSourceFile(fileName: string): SourceFile;
-        getResolvedTypeReferenceDirectives(): Map<string, ResolvedTypeReferenceDirective>;
+        getResolvedTypeReferenceDirectives(): Map<ResolvedTypeReferenceDirective>;
     }
 
     export interface TypeChecker {
@@ -2606,7 +2571,7 @@ namespace ts {
         declaredType?: Type;                // Type of class, interface, enum, type alias, or type parameter
         typeParameters?: TypeParameter[];   // Type parameters of type alias (undefined if non-generic)
         inferredClassType?: Type;           // Type of an inferred ES5 class
-        instantiations?: Map<string, Type>;         // Instantiations of generic type alias (undefined if non-generic)
+        instantiations?: Map<Type>;         // Instantiations of generic type alias (undefined if non-generic)
         mapper?: TypeMapper;                // Type mapper for instantiation alias
         referenced?: boolean;               // True if alias symbol has been referenced as a value
         containingType?: UnionOrIntersectionType; // Containing union or intersection type for synthetic property
@@ -2623,7 +2588,7 @@ namespace ts {
     /* @internal */
     export interface TransientSymbol extends Symbol, SymbolLinks { }
 
-    export type SymbolTable = Map<string, Symbol>;
+    export type SymbolTable = Map<Symbol>;
 
     /** Represents a "prefix*suffix" pattern. */
     /* @internal */
@@ -2765,7 +2730,7 @@ namespace ts {
 
     // Enum types (TypeFlags.Enum)
     export interface EnumType extends Type {
-        memberTypes: { [enumMemberValue: number]: EnumLiteralType };
+        memberTypes: Map<EnumLiteralType>;
     }
 
     // Enum types (TypeFlags.EnumLiteral)
@@ -2827,7 +2792,7 @@ namespace ts {
     // Generic class and interface types
     export interface GenericType extends InterfaceType, TypeReference {
         /* @internal */
-        instantiations: Map<string, TypeReference>;   // Generic instantiation cache
+        instantiations: Map<TypeReference>;   // Generic instantiation cache
     }
 
     export interface UnionOrIntersectionType extends Type {
@@ -3115,7 +3080,7 @@ namespace ts {
         fileNames: string[];                            // The file names that belong to the same project.
         projectRootPath: string;                        // The path to the project root directory
         safeListPath: string;                           // The path used to retrieve the safe list
-        packageNameToTypingLocation: MapLike<string>;   // The map of package names to their cached typing locations
+        packageNameToTypingLocation: Map<string>;       // The map of package names to their cached typing locations
         typingOptions: TypingOptions;                   // Used to customize the typing inference process
         compilerOptions: CompilerOptions;               // Used as a source for typing inference
         unresolvedImports: ReadonlyArray<string>;       // List of unresolved module ids from imports
@@ -3200,7 +3165,7 @@ namespace ts {
     /* @internal */
     export interface CommandLineOptionBase {
         name: string;
-        type: "string" | "number" | "boolean" | "object" | "list" | Map<string, number | string>;    // a value of a primitive type, or an object literal mapping named values to actual values
+        type: "string" | "number" | "boolean" | "object" | "list" | Map<number | string>;    // a value of a primitive type, or an object literal mapping named values to actual values
         isFilePath?: boolean;                                   // True if option value is a path or fileName
         shortName?: string;                                     // A short mnemonic for convenience - for instance, 'h' can be used in place of 'help'
         description?: DiagnosticMessage;                        // The message describing what the command line switch does
@@ -3216,7 +3181,7 @@ namespace ts {
 
     /* @internal */
     export interface CommandLineOptionOfCustomType extends CommandLineOptionBase {
-        type: Map<string, number | string>;  // an object literal mapping named values to actual values
+        type: Map<number | string>;  // an object literal mapping named values to actual values
     }
 
     /* @internal */
@@ -3543,7 +3508,7 @@ namespace ts {
         flags?: EmitFlags;
         commentRange?: TextRange;
         sourceMapRange?: TextRange;
-        tokenSourceMapRanges?: Map<SyntaxKind, TextRange>;
+        tokenSourceMapRanges?: Map<TextRange>;
         annotatedNodes?: Node[];                // Tracks Parse-tree nodes with EmitNodes for eventual cleanup.
         constantValue?: number;
     }
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index bd77d5b2138f3..f86a87e19eef4 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -84,27 +84,27 @@ namespace ts {
     }
 
     export function hasResolvedModule(sourceFile: SourceFile, moduleNameText: string): boolean {
-        return !!(sourceFile && sourceFile.resolvedModules && sourceFile.resolvedModules.get(moduleNameText));
+        return !!(sourceFile && sourceFile.resolvedModules && sourceFile.resolvedModules[moduleNameText]);
     }
 
     export function getResolvedModule(sourceFile: SourceFile, moduleNameText: string): ResolvedModuleFull {
-        return hasResolvedModule(sourceFile, moduleNameText) ? sourceFile.resolvedModules.get(moduleNameText) : undefined;
+        return hasResolvedModule(sourceFile, moduleNameText) ? sourceFile.resolvedModules[moduleNameText] : undefined;
     }
 
     export function setResolvedModule(sourceFile: SourceFile, moduleNameText: string, resolvedModule: ResolvedModuleFull): void {
         if (!sourceFile.resolvedModules) {
-            sourceFile.resolvedModules = createMap<string, ResolvedModuleFull>();
+            sourceFile.resolvedModules = createMap<ResolvedModuleFull>();
         }
 
-        sourceFile.resolvedModules.set(moduleNameText, resolvedModule);
+        sourceFile.resolvedModules[moduleNameText] = resolvedModule;
     }
 
     export function setResolvedTypeReferenceDirective(sourceFile: SourceFile, typeReferenceDirectiveName: string, resolvedTypeReferenceDirective: ResolvedTypeReferenceDirective): void {
         if (!sourceFile.resolvedTypeReferenceDirectiveNames) {
-            sourceFile.resolvedTypeReferenceDirectiveNames = createMap<string, ResolvedTypeReferenceDirective>();
+            sourceFile.resolvedTypeReferenceDirectiveNames = createMap<ResolvedTypeReferenceDirective>();
         }
 
-        sourceFile.resolvedTypeReferenceDirectiveNames.set(typeReferenceDirectiveName, resolvedTypeReferenceDirective);
+        sourceFile.resolvedTypeReferenceDirectiveNames[typeReferenceDirectiveName] = resolvedTypeReferenceDirective;
     }
 
     /* @internal */
@@ -120,13 +120,13 @@ namespace ts {
     }
 
     /* @internal */
-    export function hasChangesInResolutions<T>(names: string[], newResolutions: T[], oldResolutions: Map<string, T>, comparer: (oldResolution: T, newResolution: T) => boolean): boolean {
+    export function hasChangesInResolutions<T>(names: string[], newResolutions: T[], oldResolutions: Map<T>, comparer: (oldResolution: T, newResolution: T) => boolean): boolean {
         if (names.length !== newResolutions.length) {
             return false;
         }
         for (let i = 0; i < names.length; i++) {
             const newResolution = newResolutions[i];
-            const oldResolution = oldResolutions && oldResolutions.get(names[i]);
+            const oldResolution = oldResolutions && oldResolutions[names[i]];
             const changed =
                 oldResolution
                     ? !newResolution || !comparer(oldResolution, newResolution)
@@ -2201,7 +2201,7 @@ namespace ts {
 
     export function createDiagnosticCollection(): DiagnosticCollection {
         let nonFileDiagnostics: Diagnostic[] = [];
-        const fileDiagnostics = createMap<string, Diagnostic[]>();
+        const fileDiagnostics = createMap<Diagnostic[]>();
 
         let diagnosticsModified = false;
         let modificationCount = 0;
@@ -2219,12 +2219,11 @@ namespace ts {
         }
 
         function reattachFileDiagnostics(newFile: SourceFile): void {
-            const diagnostics = fileDiagnostics.get(newFile.fileName);
-            if (!diagnostics) {
+            if (!hasProperty(fileDiagnostics, newFile.fileName)) {
                 return;
             }
 
-            for (const diagnostic of diagnostics) {
+            for (const diagnostic of fileDiagnostics[newFile.fileName]) {
                 diagnostic.file = newFile;
             }
         }
@@ -2232,10 +2231,10 @@ namespace ts {
         function add(diagnostic: Diagnostic): void {
             let diagnostics: Diagnostic[];
             if (diagnostic.file) {
-                diagnostics = fileDiagnostics.get(diagnostic.file.fileName);
+                diagnostics = fileDiagnostics[diagnostic.file.fileName];
                 if (!diagnostics) {
                     diagnostics = [];
-                    fileDiagnostics.set(diagnostic.file.fileName, diagnostics);
+                    fileDiagnostics[diagnostic.file.fileName] = diagnostics;
                 }
             }
             else {
@@ -2255,7 +2254,7 @@ namespace ts {
         function getDiagnostics(fileName?: string): Diagnostic[] {
             sortAndDeduplicate();
             if (fileName) {
-                return fileDiagnostics.get(fileName) || [];
+                return fileDiagnostics[fileName] || [];
             }
 
             const allDiagnostics: Diagnostic[] = [];
@@ -2265,9 +2264,9 @@ namespace ts {
 
             forEach(nonFileDiagnostics, pushDiagnostic);
 
-            fileDiagnostics.forEach(diagnostics => {
-                forEach(diagnostics, pushDiagnostic);
-            });
+            for (const key in fileDiagnostics) {
+                forEach(fileDiagnostics[key], pushDiagnostic);
+            }
 
             return sortAndDeduplicateDiagnostics(allDiagnostics);
         }
@@ -2280,7 +2279,9 @@ namespace ts {
             diagnosticsModified = false;
             nonFileDiagnostics = sortAndDeduplicateDiagnostics(nonFileDiagnostics);
 
-            updateMapValues(fileDiagnostics, sortAndDeduplicateDiagnostics);
+            for (const key in fileDiagnostics) {
+                fileDiagnostics[key] = sortAndDeduplicateDiagnostics(fileDiagnostics[key]);
+            }
         }
     }
 
@@ -2290,7 +2291,7 @@ namespace ts {
     // the map below must be updated. Note that this regexp *does not* include the 'delete' character.
     // There is no reason for this other than that JSON.stringify does not handle it either.
     const escapedCharsRegExp = /[\\\"\u0000-\u001f\t\v\f\b\r\n\u2028\u2029\u0085]/g;
-    const escapedCharsMap = mapOfMapLike({
+    const escapedCharsMap = createMap({
         "\0": "\\0",
         "\t": "\\t",
         "\v": "\\v",
@@ -2317,7 +2318,7 @@ namespace ts {
         return s;
 
         function getReplacement(c: string) {
-            return escapedCharsMap.get(c) || get16BitUnicodeEscapeSequence(c.charCodeAt(0));
+            return escapedCharsMap[c] || get16BitUnicodeEscapeSequence(c.charCodeAt(0));
         }
     }
 
@@ -3349,19 +3350,18 @@ namespace ts {
         return false;
     }
 
-    const syntaxKindCache = createMap<SyntaxKind, string>();
+    const syntaxKindCache = createMap<string>();
 
     export function formatSyntaxKind(kind: SyntaxKind): string {
         const syntaxKindEnum = (<any>ts).SyntaxKind;
         if (syntaxKindEnum) {
-            const cached = syntaxKindCache.get(kind);
-            if (cached !== undefined) {
-                return cached;
+            if (syntaxKindCache[kind]) {
+                return syntaxKindCache[kind];
             }
 
             for (const name in syntaxKindEnum) {
                 if (syntaxKindEnum[name] === kind) {
-                    return setAndReturn(syntaxKindCache, kind, `${kind}(${name})`);
+                    return syntaxKindCache[kind] = kind.toString() + " (" + name + ")";
                 }
             }
         }
@@ -3498,8 +3498,8 @@ namespace ts {
 
     export interface ExternalModuleInfo {
         externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[]; // imports of other external modules
-        exportSpecifiers: Map<string, ExportSpecifier[]>; // export specifiers by name
-        exportedBindings: Map<number, Identifier[]>; // exported names of local declarations
+        exportSpecifiers: Map<ExportSpecifier[]>; // export specifiers by name
+        exportedBindings: Map<Identifier[]>; // exported names of local declarations
         exportedNames: Identifier[]; // all exported names local to module
         exportEquals: ExportAssignment | undefined; // an export= declaration if one was present
         hasExportStarsToExportValues: boolean; // whether this module contains export*
@@ -3507,9 +3507,9 @@ namespace ts {
 
     export function collectExternalModuleInfo(sourceFile: SourceFile, resolver: EmitResolver): ExternalModuleInfo {
         const externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[] = [];
-        const exportSpecifiers = createMap<string, ExportSpecifier[]>();
-        const exportedBindings = createMap<number, Identifier[]>();
-        const uniqueExports = createMap<string, Identifier>();
+        const exportSpecifiers = createMap<ExportSpecifier[]>();
+        const exportedBindings = createMap<Identifier[]>();
+        const uniqueExports = createMap<Identifier>();
         let hasExportDefault = false;
         let exportEquals: ExportAssignment = undefined;
         let hasExportStarsToExportValues = false;
@@ -3546,7 +3546,7 @@ namespace ts {
                     else {
                         // export { x, y }
                         for (const specifier of (<ExportDeclaration>node).exportClause.elements) {
-                            if (!uniqueExports.has(specifier.name.text)) {
+                            if (!uniqueExports[specifier.name.text]) {
                                 const name = specifier.propertyName || specifier.name;
                                 multiMapAdd(exportSpecifiers, name.text, specifier);
 
@@ -3557,7 +3557,7 @@ namespace ts {
                                     multiMapAdd(exportedBindings, getOriginalNodeId(decl), specifier.name);
                                 }
 
-                                uniqueExports.set(specifier.name.text, specifier.name);
+                                uniqueExports[specifier.name.text] = specifier.name;
                             }
                         }
                     }
@@ -3590,9 +3590,9 @@ namespace ts {
                         else {
                             // export function x() { }
                             const name = (<FunctionDeclaration>node).name;
-                            if (!uniqueExports.has(name.text)) {
+                            if (!uniqueExports[name.text]) {
                                 multiMapAdd(exportedBindings, getOriginalNodeId(node), name);
-                                uniqueExports.set(name.text, name);
+                                uniqueExports[name.text] = name;
                             }
                         }
                     }
@@ -3610,9 +3610,9 @@ namespace ts {
                         else {
                             // export class x { }
                             const name = (<ClassDeclaration>node).name;
-                            if (!uniqueExports.has(name.text)) {
+                            if (!uniqueExports[name.text]) {
                                 multiMapAdd(exportedBindings, getOriginalNodeId(node), name);
-                                uniqueExports.set(name.text, name);
+                                uniqueExports[name.text] = name;
                             }
                         }
                     }
@@ -3621,14 +3621,14 @@ namespace ts {
         }
 
         let exportedNames: Identifier[];
-        uniqueExports.forEach(exported => {
-            exportedNames = ts.append(exportedNames, exported);
-        });
+        for (const key in uniqueExports) {
+            exportedNames = ts.append(exportedNames, uniqueExports[key]);
+        }
 
         return { externalImports, exportSpecifiers, exportEquals, hasExportStarsToExportValues, exportedBindings, exportedNames };
     }
 
-    function collectExportedVariableInfo(decl: VariableDeclaration | BindingElement, uniqueExports: Map<string, Identifier>) {
+    function collectExportedVariableInfo(decl: VariableDeclaration | BindingElement, uniqueExports: Map<Identifier>) {
         if (isBindingPattern(decl.name)) {
             for (const element of decl.name.elements) {
                 if (!isOmittedExpression(element)) {
@@ -3637,8 +3637,8 @@ namespace ts {
             }
         }
         else if (!isGeneratedIdentifier(decl.name)) {
-            if (!uniqueExports.has(decl.name.text)) {
-                uniqueExports.set(decl.name.text, decl.name);
+            if (!uniqueExports[decl.name.text]) {
+                uniqueExports[decl.name.text] = decl.name;
             }
         }
     }
diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index fb1c572f08241..609031a82215a 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -46,54 +46,54 @@ namespace ts {
      *       supplant the existing `forEachChild` implementation if performance is not
      *       significantly impacted.
      */
-    const nodeEdgeTraversalMap = createMap<SyntaxKind, NodeTraversalPath>([
-        [SyntaxKind.QualifiedName, [
+    const nodeEdgeTraversalMap = createMap<NodeTraversalPath>({
+        [SyntaxKind.QualifiedName]: [
             { name: "left", test: isEntityName },
             { name: "right", test: isIdentifier }
-        ]],
-        [SyntaxKind.Decorator, [
+        ],
+        [SyntaxKind.Decorator]: [
             { name: "expression", test: isLeftHandSideExpression }
-        ]],
-        [SyntaxKind.TypeAssertionExpression, [
+        ],
+        [SyntaxKind.TypeAssertionExpression]: [
             { name: "type", test: isTypeNode },
             { name: "expression", test: isUnaryExpression }
-        ]],
-        [SyntaxKind.AsExpression, [
+        ],
+        [SyntaxKind.AsExpression]: [
             { name: "expression", test: isExpression },
             { name: "type", test: isTypeNode }
-        ]],
-        [SyntaxKind.NonNullExpression, [
+        ],
+        [SyntaxKind.NonNullExpression]: [
             { name: "expression", test: isLeftHandSideExpression }
-        ]],
-        [SyntaxKind.EnumDeclaration, [
+        ],
+        [SyntaxKind.EnumDeclaration]: [
             { name: "decorators", test: isDecorator },
             { name: "modifiers", test: isModifier },
             { name: "name", test: isIdentifier },
             { name: "members", test: isEnumMember }
-        ]],
-        [SyntaxKind.ModuleDeclaration, [
+        ],
+        [SyntaxKind.ModuleDeclaration]: [
             { name: "decorators", test: isDecorator },
             { name: "modifiers", test: isModifier },
             { name: "name", test: isModuleName },
             { name: "body", test: isModuleBody }
-        ]],
-        [SyntaxKind.ModuleBlock, [
+        ],
+        [SyntaxKind.ModuleBlock]: [
             { name: "statements", test: isStatement }
-        ]],
-        [SyntaxKind.ImportEqualsDeclaration, [
+        ],
+        [SyntaxKind.ImportEqualsDeclaration]: [
             { name: "decorators", test: isDecorator },
             { name: "modifiers", test: isModifier },
             { name: "name", test: isIdentifier },
             { name: "moduleReference", test: isModuleReference }
-        ]],
-        [SyntaxKind.ExternalModuleReference, [
+        ],
+        [SyntaxKind.ExternalModuleReference]: [
             { name: "expression", test: isExpression, optional: true }
-        ]],
-        [SyntaxKind.EnumMember, [
+        ],
+        [SyntaxKind.EnumMember]: [
             { name: "name", test: isPropertyName },
             { name: "initializer", test: isExpression, optional: true, parenthesize: parenthesizeExpressionForList }
-        ]]
-    ]);
+        ]
+    });
 
     function reduceNode<T>(node: Node, f: (memo: T, node: Node) => T, initial: T) {
         return node ? f(initial, node) : initial;
@@ -520,7 +520,7 @@ namespace ts {
                 break;
 
             default:
-                const edgeTraversalPath = nodeEdgeTraversalMap.get(kind);
+                const edgeTraversalPath = nodeEdgeTraversalMap[kind];
                 if (edgeTraversalPath) {
                     for (const edge of edgeTraversalPath) {
                         const value = (<MapLike<any>>node)[edge.name];
@@ -1142,10 +1142,10 @@ namespace ts {
 
             default:
                 let updated: Node & MapLike<any>;
-                const edgeTraversalPath = nodeEdgeTraversalMap.get(kind);
+                const edgeTraversalPath = nodeEdgeTraversalMap[kind];
                 if (edgeTraversalPath) {
                     for (const edge of edgeTraversalPath) {
-                        const value = <Node | NodeArray<Node>>(<Node & MapLike<any>>node)[edge.name];
+                        const value = <Node | NodeArray<Node>>(<Node & Map<any>>node)[edge.name];
                         if (value !== undefined) {
                             const visited = isArray(value)
                                 ? visitNodes(value, visitor, edge.test, 0, value.length, edge.parenthesize, node)
diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index 88181d5edd27b..b008ca653702d 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -86,7 +86,7 @@ namespace FourSlash {
 
     export import IndentStyle = ts.IndentStyle;
 
-    const entityMap = ts.mapOfMapLike({
+    const entityMap = ts.createMap({
         "&": "&amp;",
         "\"": "&quot;",
         "'": "&#39;",
@@ -96,7 +96,7 @@ namespace FourSlash {
     });
 
     export function escapeXmlAttributeValue(s: string) {
-        return s.replace(/[&<>"'\/]/g, ch => entityMap.get(ch));
+        return s.replace(/[&<>"'\/]/g, ch => entityMap[ch]);
     }
 
     // Name of testcase metadata including ts.CompilerOptions properties that will be used by globalOptions
@@ -189,7 +189,7 @@ namespace FourSlash {
 
         public formatCodeSettings: ts.FormatCodeSettings;
 
-        private inputFiles = ts.createMap<string, string>();  // Map between inputFile's fileName and its content for easily looking up when resolving references
+        private inputFiles = ts.createMap<string>();  // Map between inputFile's fileName and its content for easily looking up when resolving references
 
         private static getDisplayPartsJson(displayParts: ts.SymbolDisplayPart[]) {
             let result = "";
@@ -222,7 +222,7 @@ namespace FourSlash {
             }
 
             function tryAdd(path: string) {
-                const inputFile = inputFiles.get(path);
+                const inputFile = inputFiles[path];
                 if (inputFile && !Harness.isDefaultLibraryFile(path)) {
                     languageServiceAdapterHost.addScript(path, inputFile, /*isRootFile*/ true);
                     return true;
@@ -256,7 +256,7 @@ namespace FourSlash {
 
             ts.forEach(testData.files, file => {
                 // Create map between fileName and its content for easily looking up when resolveReference flag is specified
-                this.inputFiles.set(file.fileName, file.content);
+                this.inputFiles[file.fileName] = file.content;
 
                 if (ts.getBaseFileName(file.fileName).toLowerCase() === "tsconfig.json") {
                     const configJson = ts.parseConfigFileTextToJson(file.fileName, file.content);
@@ -322,11 +322,11 @@ namespace FourSlash {
             }
             else {
                 // resolveReference file-option is not specified then do not resolve any files and include all inputFiles
-                this.inputFiles.forEach((inputFile, fileName) => {
+                for (const fileName in this.inputFiles) {
                     if (!Harness.isDefaultLibraryFile(fileName)) {
-                        this.languageServiceAdapterHost.addScript(fileName, inputFile, /*isRootFile*/ true);
+                        this.languageServiceAdapterHost.addScript(fileName, this.inputFiles[fileName], /*isRootFile*/ true);
                     }
-                });
+                }
                 this.languageServiceAdapterHost.addScript(Harness.Compiler.defaultLibFileName,
                     Harness.Compiler.getDefaultLibrarySourceFile().text, /*isRootFile*/ false);
             }
@@ -674,11 +674,13 @@ namespace FourSlash {
 
         public noItemsWithSameNameButDifferentKind(): void {
             const completions = this.getCompletionListAtCaret();
-            const uniqueItems = ts.createMap<string, string>();
+            const uniqueItems = ts.createMap<string>();
             for (const item of completions.entries) {
-                if (!ts.setIfNotSet(uniqueItems, item.name, item.kind)) {
-                    const uniqueItem = uniqueItems.get(item.name);
-                    assert.equal(item.kind, uniqueItem, `Items should have the same kind, got ${item.kind} and ${uniqueItem}`);
+                if (!(item.name in uniqueItems)) {
+                    uniqueItems[item.name] = item.kind;
+                }
+                else {
+                    assert.equal(item.kind, uniqueItems[item.name], `Items should have the same kind, got ${item.kind} and ${uniqueItems[item.name]}`);
                 }
             }
         }
@@ -856,7 +858,7 @@ namespace FourSlash {
         }
 
         public verifyRangesWithSameTextReferenceEachOther() {
-            this.rangesByTextMap().forEach(ranges => this.verifyRangesReferenceEachOther(ranges));
+            ts.forEachProperty(this.rangesByText(), ranges => this.verifyRangesReferenceEachOther(ranges));
         }
 
         public verifyDisplayPartsOfReferencedSymbol(expected: ts.SymbolDisplayPart[]) {
@@ -932,8 +934,7 @@ namespace FourSlash {
         }
 
         public verifyQuickInfos(namesAndTexts: { [name: string]: string | [string, string] }) {
-            for (const name in namesAndTexts) {
-                const text = namesAndTexts[name];
+            ts.forEachProperty(ts.createMap(namesAndTexts), (text, name) => {
                 if (text instanceof Array) {
                     assert(text.length === 2);
                     const [expectedText, expectedDocumentation] = text;
@@ -942,7 +943,7 @@ namespace FourSlash {
                 else {
                     this.verifyQuickInfoAt(name, text);
                 }
-            }
+            });
         }
 
         public verifyQuickInfoString(expectedText: string, expectedDocumentation?: string) {
@@ -1776,8 +1777,8 @@ namespace FourSlash {
             return this.testData.ranges;
         }
 
-        private rangesByTextMap(): ts.Map<string, Range[]> {
-            const result = ts.createMap<string, Range[]>();
+        public rangesByText(): ts.Map<Range[]> {
+            const result = ts.createMap<Range[]>();
             for (const range of this.getRanges()) {
                 const text = this.rangeText(range);
                 ts.multiMapAdd(result, text, range);
@@ -1785,10 +1786,6 @@ namespace FourSlash {
             return result;
         }
 
-        public rangesByText(): ts.MapLike<Range[]> {
-            return ts.mapLikeOfMap(this.rangesByTextMap());
-        }
-
         private rangeText({fileName, start, end}: Range): string {
             return this.getFileContent(fileName).slice(start, end);
         }
@@ -2069,7 +2066,7 @@ namespace FourSlash {
 
         public verifyBraceCompletionAtPosition(negative: boolean, openingBrace: string) {
 
-            const openBraceMap = ts.mapOfMapLike<ts.CharacterCodes>({
+            const openBraceMap = ts.createMap<ts.CharacterCodes>({
                 "(": ts.CharacterCodes.openParen,
                 "{": ts.CharacterCodes.openBrace,
                 "[": ts.CharacterCodes.openBracket,
@@ -2079,7 +2076,7 @@ namespace FourSlash {
                 "<": ts.CharacterCodes.lessThan
             });
 
-            const charCode = openBraceMap.get(openingBrace);
+            const charCode = openBraceMap[openingBrace];
 
             if (!charCode) {
                 this.raiseError(`Invalid openingBrace '${openingBrace}' specified.`);
@@ -2954,7 +2951,7 @@ namespace FourSlashInterface {
             return this.state.getRanges();
         }
 
-        public rangesByText(): ts.MapLike<FourSlash.Range[]> {
+        public rangesByText(): ts.Map<FourSlash.Range[]> {
             return this.state.rangesByText();
         }
 
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index a029dfc38014d..17e67b053a3ee 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -922,19 +922,19 @@ namespace Harness {
         export const defaultLibFileName = "lib.d.ts";
         export const es2015DefaultLibFileName = "lib.es2015.d.ts";
 
-        const libFileNameSourceFileMap = ts.createMap<string, ts.SourceFile>([[
-            defaultLibFileName,
-            createSourceFileAndAssertInvariants(defaultLibFileName, IO.readFile(libFolder + "lib.es5.d.ts"), /*languageVersion*/ ts.ScriptTarget.Latest)
-        ]]);
+        const libFileNameSourceFileMap = ts.createMap<ts.SourceFile>({
+            [defaultLibFileName]: createSourceFileAndAssertInvariants(defaultLibFileName, IO.readFile(libFolder + "lib.es5.d.ts"), /*languageVersion*/ ts.ScriptTarget.Latest)
+        });
 
         export function getDefaultLibrarySourceFile(fileName = defaultLibFileName): ts.SourceFile {
             if (!isDefaultLibraryFile(fileName)) {
                 return undefined;
             }
 
-            const sourceFile = libFileNameSourceFileMap.get(fileName);
-            return sourceFile || ts.setAndReturn(libFileNameSourceFileMap, fileName,
-                createSourceFileAndAssertInvariants(fileName, IO.readFile(libFolder + fileName), ts.ScriptTarget.Latest));
+            if (!libFileNameSourceFileMap[fileName]) {
+                libFileNameSourceFileMap[fileName] = createSourceFileAndAssertInvariants(fileName, IO.readFile(libFolder + fileName), ts.ScriptTarget.Latest);
+            }
+            return libFileNameSourceFileMap[fileName];
         }
 
         export function getDefaultLibFileName(options: ts.CompilerOptions): string {
@@ -1086,16 +1086,16 @@ namespace Harness {
             { name: "symlink", type: "string" }
         ];
 
-        let optionsIndex: ts.Map<string, ts.CommandLineOption>;
+        let optionsIndex: ts.Map<ts.CommandLineOption>;
         function getCommandLineOption(name: string): ts.CommandLineOption {
             if (!optionsIndex) {
-                optionsIndex = ts.createMap<string, ts.CommandLineOption>();
+                optionsIndex = ts.createMap<ts.CommandLineOption>();
                 const optionDeclarations = harnessOptionDeclarations.concat(ts.optionDeclarations);
                 for (const option of optionDeclarations) {
-                    optionsIndex.set(option.name.toLowerCase(), option);
+                    optionsIndex[option.name.toLowerCase()] = option;
                 }
             }
-            return optionsIndex.get(name.toLowerCase());
+            return optionsIndex[name.toLowerCase()];
         }
 
         export function setCompilerOptionsFromHarnessSetting(settings: Harness.TestCaseParser.CompilerSettings, options: ts.CompilerOptions & HarnessOptions): void {
@@ -1452,10 +1452,10 @@ namespace Harness {
 
             const fullWalker = new TypeWriterWalker(program, /*fullTypeCheck*/ true);
 
-            const fullResults = ts.createMap<string, TypeWriterResult[]>();
+            const fullResults = ts.createMap<TypeWriterResult[]>();
 
             for (const sourceFile of allFiles) {
-                fullResults.set(sourceFile.unitName, fullWalker.getTypeAndSymbols(sourceFile.unitName));
+                fullResults[sourceFile.unitName] = fullWalker.getTypeAndSymbols(sourceFile.unitName);
             }
 
             // Produce baselines.  The first gives the types for all expressions.
@@ -1502,13 +1502,13 @@ namespace Harness {
                 Harness.Baseline.runBaseline(outputFileName, () => fullBaseLine, opts);
             }
 
-            function generateBaseLine(typeWriterResults: ts.Map<string, TypeWriterResult[]>, isSymbolBaseline: boolean): string {
+            function generateBaseLine(typeWriterResults: ts.Map<TypeWriterResult[]>, isSymbolBaseline: boolean): string {
                 const typeLines: string[] = [];
                 const typeMap: { [fileName: string]: { [lineNum: number]: string[]; } } = {};
 
                 allFiles.forEach(file => {
                     const codeLines = file.content.split("\n");
-                    typeWriterResults.get(file.unitName).forEach(result => {
+                    typeWriterResults[file.unitName].forEach(result => {
                         if (isSymbolBaseline && !result.symbol) {
                             return;
                         }
diff --git a/src/harness/harnessLanguageService.ts b/src/harness/harnessLanguageService.ts
index ee7bc43ac2aec..889d4f28ce9a9 100644
--- a/src/harness/harnessLanguageService.ts
+++ b/src/harness/harnessLanguageService.ts
@@ -262,7 +262,7 @@ namespace Harness.LanguageService {
                 this.getModuleResolutionsForFile = (fileName) => {
                     const scriptInfo = this.getScriptInfo(fileName);
                     const preprocessInfo = ts.preProcessFile(scriptInfo.content, /*readImportFiles*/ true);
-                    const imports: ts.MapLike<string> = {};
+                    const imports = ts.createMap<string>();
                     for (const module of preprocessInfo.importedFiles) {
                         const resolutionInfo = ts.resolveModuleName(module.fileName, fileName, compilerOptions, moduleResolutionHost);
                         if (resolutionInfo.resolvedModule) {
@@ -275,7 +275,7 @@ namespace Harness.LanguageService {
                     const scriptInfo = this.getScriptInfo(fileName);
                     if (scriptInfo) {
                         const preprocessInfo = ts.preProcessFile(scriptInfo.content, /*readImportFiles*/ false);
-                        const resolutions: ts.MapLike<ts.ResolvedTypeReferenceDirective> = {};
+                        const resolutions = ts.createMap<ts.ResolvedTypeReferenceDirective>();
                         const settings = this.nativeHost.getCompilationSettings();
                         for (const typeReferenceDirective of preprocessInfo.typeReferenceDirectives) {
                             const resolutionInfo = ts.resolveTypeReferenceDirective(typeReferenceDirective.fileName, fileName, settings, moduleResolutionHost);
diff --git a/src/harness/loggedIO.ts b/src/harness/loggedIO.ts
index a4cd4d36b39da..eeb47f0cfa03c 100644
--- a/src/harness/loggedIO.ts
+++ b/src/harness/loggedIO.ts
@@ -91,11 +91,13 @@ namespace Playback {
     }
 
     function memoize<T>(func: (s: string) => T): Memoized<T> {
-        const lookup = ts.createMap<string, T>();
-        const run: Memoized<T> = <Memoized<T>>((s: string) =>
-            ts.getOrUpdateAndAllowUndefined(lookup, s, func));
+        let lookup: { [s: string]: T } = {};
+        const run: Memoized<T> = <Memoized<T>>((s: string) => {
+            if (lookup.hasOwnProperty(s)) return lookup[s];
+            return lookup[s] = func(s);
+        });
         run.reset = () => {
-            lookup.clear();
+            lookup = undefined;
         };
 
         return run;
diff --git a/src/harness/projectsRunner.ts b/src/harness/projectsRunner.ts
index 99c395f16996b..f7541dc9bfe9e 100644
--- a/src/harness/projectsRunner.ts
+++ b/src/harness/projectsRunner.ts
@@ -256,20 +256,17 @@ class ProjectRunner extends RunnerBase {
                 // Set the values specified using json
                 const optionNameMap = ts.arrayToMap(ts.optionDeclarations, option => option.name);
                 for (const name in testCase) {
-                    if (name !== "mapRoot" && name !== "sourceRoot") {
-                        const option = optionNameMap.get(name);
-                        if (option !== undefined) {
-                            const optType = option.type;
-                            let value = <any>testCase[name];
-                            if (typeof optType !== "string") {
-                                const key = value.toLowerCase();
-                                const translation = optType.get(key);
-                                if (translation !== undefined) {
-                                    value = translation;
-                                }
+                    if (name !== "mapRoot" && name !== "sourceRoot" && name in optionNameMap) {
+                        const option = optionNameMap[name];
+                        const optType = option.type;
+                        let value = <any>testCase[name];
+                        if (typeof optType !== "string") {
+                            const key = value.toLowerCase();
+                            if (key in optType) {
+                                value = optType[key];
                             }
-                            compilerOptions[option.name] = value;
                         }
+                        compilerOptions[option.name] = value;
                     }
                 }
 
diff --git a/src/harness/unittests/cachingInServerLSHost.ts b/src/harness/unittests/cachingInServerLSHost.ts
index 1bfff0bf6a920..953edd98b6ab4 100644
--- a/src/harness/unittests/cachingInServerLSHost.ts
+++ b/src/harness/unittests/cachingInServerLSHost.ts
@@ -6,25 +6,24 @@ namespace ts {
         content: string;
     }
 
-    function createDefaultServerHost(fileMap: Map<string, File>): server.ServerHost {
-        const existingDirectories = createSet();
-        forEachKeyInMap(fileMap, name => {
+    function createDefaultServerHost(fileMap: Map<File>): server.ServerHost {
+        const existingDirectories = createMap<boolean>();
+        for (const name in fileMap) {
             let dir = getDirectoryPath(name);
             let previous: string;
             do {
-                existingDirectories.add(dir);
+                existingDirectories[dir] = true;
                 previous = dir;
                 dir = getDirectoryPath(dir);
             } while (dir !== previous);
-        });
+        }
         return {
             args: <string[]>[],
             newLine: "\r\n",
             useCaseSensitiveFileNames: false,
             write: noop,
             readFile: (path: string): string => {
-                const file = fileMap.get(path);
-                return file !== undefined ? file.content : undefined;
+                return path in fileMap ? fileMap[path].content : undefined;
             },
             writeFile: (_path: string, _data: string, _writeByteOrderMark?: boolean) => {
                 return ts.notImplemented();
@@ -33,10 +32,10 @@ namespace ts {
                 return ts.notImplemented();
             },
             fileExists: (path: string): boolean => {
-                return fileMap.has(path);
+                return path in fileMap;
             },
             directoryExists: (path: string): boolean => {
-                return existingDirectories.has(path);
+                return existingDirectories[path] || false;
             },
             createDirectory: noop,
             getExecutingFilePath: (): string => {
@@ -99,7 +98,7 @@ namespace ts {
                 content: `foo()`
             };
 
-            const serverHost = createDefaultServerHost(mapOfMapLike({ [root.name]: root, [imported.name]: imported }));
+            const serverHost = createDefaultServerHost(createMap({ [root.name]: root, [imported.name]: imported }));
             const { project, rootScriptInfo } = createProject(root.name, serverHost);
 
             // ensure that imported file was found
@@ -183,7 +182,7 @@ namespace ts {
                 content: `export var y = 1`
             };
 
-            const fileMap = mapOfMapLike({ [root.name]: root });
+            const fileMap = createMap({ [root.name]: root });
             const serverHost = createDefaultServerHost(fileMap);
             const originalFileExists = serverHost.fileExists;
 
@@ -207,7 +206,7 @@ namespace ts {
             assert.isTrue(typeof diags[0].messageText === "string" && ((<string>diags[0].messageText).indexOf("Cannot find module") === 0), "should be 'cannot find module' message");
 
             // assert that import will success once file appear on disk
-            fileMap.set(imported.name, imported);
+            fileMap[imported.name] = imported;
             fileExistsCalledForBar = false;
             rootScriptInfo.editContent(0, root.content.length, `import {y} from "bar"`);
 
diff --git a/src/harness/unittests/moduleResolution.ts b/src/harness/unittests/moduleResolution.ts
index 5f07e46cbcfca..104d9f9e394eb 100644
--- a/src/harness/unittests/moduleResolution.ts
+++ b/src/harness/unittests/moduleResolution.ts
@@ -32,11 +32,11 @@ namespace ts {
         const map = arrayToMap(files, f => f.name);
 
         if (hasDirectoryExists) {
-            const directories = createSet();
+            const directories = createMap<string>();
             for (const f of files) {
                 let name = getDirectoryPath(f.name);
                 while (true) {
-                    directories.add(name);
+                    directories[name] = name;
                     const baseName = getDirectoryPath(name);
                     if (baseName === name) {
                         break;
@@ -46,19 +46,20 @@ namespace ts {
             }
             return {
                 readFile,
-                directoryExists: path => directories.has(path),
+                directoryExists: path => {
+                    return path in directories;
+                },
                 fileExists: path => {
-                    assert.isTrue(directories.has(getDirectoryPath(path)), `'fileExists' '${path}' request in non-existing directory`);
-                    return map.has(path);
+                    assert.isTrue(getDirectoryPath(path) in directories, `'fileExists' '${path}' request in non-existing directory`);
+                    return path in map;
                 }
             };
         }
         else {
-            return { readFile, fileExists: path => map.has(path) };
+            return { readFile, fileExists: path => path in map, };
         }
         function readFile(path: string): string {
-            const file = map.get(path);
-            return file !== undefined ? file.content : undefined;
+            return path in map ? map[path].content : undefined;
         }
     }
 
@@ -314,13 +315,12 @@ namespace ts {
     });
 
     describe("Module resolution - relative imports", () => {
-        function test(files: Map<string, string>, currentDirectory: string, rootFiles: string[], expectedFilesCount: number, relativeNamesToCheck: string[]) {
+        function test(files: Map<string>, currentDirectory: string, rootFiles: string[], expectedFilesCount: number, relativeNamesToCheck: string[]) {
             const options: CompilerOptions = { module: ModuleKind.CommonJS };
             const host: CompilerHost = {
                 getSourceFile: (fileName: string, languageVersion: ScriptTarget) => {
                     const path = normalizePath(combinePaths(currentDirectory, fileName));
-                    const file = files.get(path);
-                    return file !== undefined ? createSourceFile(fileName, file, languageVersion) : undefined;
+                    return path in files ? createSourceFile(fileName, files[path], languageVersion) : undefined;
                 },
                 getDefaultLibFileName: () => "lib.d.ts",
                 writeFile: notImplemented,
@@ -331,7 +331,7 @@ namespace ts {
                 useCaseSensitiveFileNames: () => false,
                 fileExists: fileName => {
                     const path = normalizePath(combinePaths(currentDirectory, fileName));
-                    return files.has(path);
+                    return path in files;
                 },
                 readFile: notImplemented
             };
@@ -351,7 +351,7 @@ namespace ts {
         }
 
         it("should find all modules", () => {
-            const files = mapOfMapLike({
+            const files = createMap({
                 "/a/b/c/first/shared.ts": `
 class A {}
 export = A`,
@@ -370,7 +370,7 @@ export = C;
         });
 
         it("should find modules in node_modules", () => {
-            const files = mapOfMapLike({
+            const files = createMap({
                 "/parent/node_modules/mod/index.d.ts": "export var x",
                 "/parent/app/myapp.ts": `import {x} from "mod"`
             });
@@ -378,7 +378,7 @@ export = C;
         });
 
         it("should find file referenced via absolute and relative names", () => {
-            const files = mapOfMapLike({
+            const files = createMap({
                 "/a/b/c.ts": `/// <reference path="b.ts"/>`,
                 "/a/b/b.ts": "var x"
             });
@@ -388,10 +388,10 @@ export = C;
 
     describe("Files with different casing", () => {
         const library = createSourceFile("lib.d.ts", "", ScriptTarget.ES5);
-        function test(files: Map<string, string>, options: CompilerOptions, currentDirectory: string, useCaseSensitiveFileNames: boolean, rootFiles: string[], diagnosticCodes: number[]): void {
+        function test(files: Map<string>, options: CompilerOptions, currentDirectory: string, useCaseSensitiveFileNames: boolean, rootFiles: string[], diagnosticCodes: number[]): void {
             const getCanonicalFileName = createGetCanonicalFileName(useCaseSensitiveFileNames);
             if (!useCaseSensitiveFileNames) {
-                files = transformKeys(files, getCanonicalFileName);
+                files = reduceProperties(files, (files, file, fileName) => (files[getCanonicalFileName(fileName)] = file, files), createMap<string>());
             }
 
             const host: CompilerHost = {
@@ -400,8 +400,7 @@ export = C;
                         return library;
                     }
                     const path = getCanonicalFileName(normalizePath(combinePaths(currentDirectory, fileName)));
-                    const file = files.get(path);
-                    return file !== undefined ? createSourceFile(fileName, file, languageVersion) : undefined;
+                    return path in files ? createSourceFile(fileName, files[path], languageVersion) : undefined;
                 },
                 getDefaultLibFileName: () => "lib.d.ts",
                 writeFile: notImplemented,
@@ -412,7 +411,7 @@ export = C;
                 useCaseSensitiveFileNames: () => useCaseSensitiveFileNames,
                 fileExists: fileName => {
                     const path = getCanonicalFileName(normalizePath(combinePaths(currentDirectory, fileName)));
-                    return files.has(path);
+                    return path in files;
                 },
                 readFile: notImplemented
             };
@@ -425,7 +424,7 @@ export = C;
         }
 
         it("should succeed when the same file is referenced using absolute and relative names", () => {
-            const files = mapOfMapLike({
+            const files = createMap({
                 "/a/b/c.ts": `/// <reference path="d.ts"/>`,
                 "/a/b/d.ts": "var x"
             });
@@ -433,7 +432,7 @@ export = C;
         });
 
         it("should fail when two files used in program differ only in casing (tripleslash references)", () => {
-            const files = mapOfMapLike({
+            const files = createMap({
                 "/a/b/c.ts": `/// <reference path="D.ts"/>`,
                 "/a/b/d.ts": "var x"
             });
@@ -441,7 +440,7 @@ export = C;
         });
 
         it("should fail when two files used in program differ only in casing (imports)", () => {
-            const files = mapOfMapLike({
+            const files = createMap({
                 "/a/b/c.ts": `import {x} from "D"`,
                 "/a/b/d.ts": "export var x"
             });
@@ -449,7 +448,7 @@ export = C;
         });
 
         it("should fail when two files used in program differ only in casing (imports, relative module names)", () => {
-            const files = mapOfMapLike({
+            const files = createMap({
                 "moduleA.ts": `import {x} from "./ModuleB"`,
                 "moduleB.ts": "export var x"
             });
@@ -457,7 +456,7 @@ export = C;
         });
 
         it("should fail when two files exist on disk that differs only in casing", () => {
-            const files = mapOfMapLike({
+            const files = createMap({
                 "/a/b/c.ts": `import {x} from "D"`,
                 "/a/b/D.ts": "export var x",
                 "/a/b/d.ts": "export var y"
@@ -466,7 +465,7 @@ export = C;
         });
 
         it("should fail when module name in 'require' calls has inconsistent casing", () => {
-            const files = mapOfMapLike({
+            const files = createMap({
                 "moduleA.ts": `import a = require("./ModuleC")`,
                 "moduleB.ts": `import a = require("./moduleC")`,
                 "moduleC.ts": "export var x"
@@ -475,7 +474,7 @@ export = C;
         });
 
         it("should fail when module names in 'require' calls has inconsistent casing and current directory has uppercase chars", () => {
-            const files = mapOfMapLike({
+            const files = createMap({
                 "/a/B/c/moduleA.ts": `import a = require("./ModuleC")`,
                 "/a/B/c/moduleB.ts": `import a = require("./moduleC")`,
                 "/a/B/c/moduleC.ts": "export var x",
@@ -487,7 +486,7 @@ import b = require("./moduleB");
             test(files, { module: ts.ModuleKind.CommonJS, forceConsistentCasingInFileNames: true },  "/a/B/c", /*useCaseSensitiveFileNames*/ false, ["moduleD.ts"], [1149]);
         });
         it("should not fail when module names in 'require' calls has consistent casing and current directory has uppercase chars", () => {
-            const files = mapOfMapLike({
+            const files = createMap({
                 "/a/B/c/moduleA.ts": `import a = require("./moduleC")`,
                 "/a/B/c/moduleB.ts": `import a = require("./moduleC")`,
                 "/a/B/c/moduleC.ts": "export var x",
@@ -1045,8 +1044,8 @@ import b = require("./moduleB");
             const names = map(files, f => f.name);
             const sourceFiles = arrayToMap(map(files, f => createSourceFile(f.name, f.content, ScriptTarget.ES2015)), f => f.fileName);
             const compilerHost: CompilerHost = {
-                fileExists : fileName => sourceFiles.has(fileName),
-                getSourceFile: fileName => sourceFiles.get(fileName),
+                fileExists : fileName => fileName in sourceFiles,
+                getSourceFile: fileName => sourceFiles[fileName],
                 getDefaultLibFileName: () => "lib.d.ts",
                 writeFile: notImplemented,
                 getCurrentDirectory: () => "/",
@@ -1054,10 +1053,7 @@ import b = require("./moduleB");
                 getCanonicalFileName: f => f.toLowerCase(),
                 getNewLine: () => "\r\n",
                 useCaseSensitiveFileNames: () => false,
-                readFile: fileName => {
-                    const file = sourceFiles.get(fileName);
-                    return file !== undefined ? file.text : undefined;
-                }
+                readFile: fileName => fileName in sourceFiles ? sourceFiles[fileName].text : undefined
             };
             const program1 = createProgram(names, {}, compilerHost);
             const diagnostics1 = program1.getFileProcessingDiagnostics().getDiagnostics();
diff --git a/src/harness/unittests/reuseProgramStructure.ts b/src/harness/unittests/reuseProgramStructure.ts
index 6a34bbd193c87..215e05658a964 100644
--- a/src/harness/unittests/reuseProgramStructure.ts
+++ b/src/harness/unittests/reuseProgramStructure.ts
@@ -106,7 +106,7 @@ namespace ts {
 
         return {
             getSourceFile(fileName): SourceFile {
-                return files.get(fileName);
+                return files[fileName];
             },
             getDefaultLibFileName(): string {
                 return "lib.d.ts";
@@ -127,10 +127,9 @@ namespace ts {
             getNewLine(): string {
                 return sys ? sys.newLine : newLine;
             },
-            fileExists: fileName => files.has(fileName),
+            fileExists: fileName => fileName in files,
             readFile: fileName => {
-                const file = files.get(fileName);
-                return file !== undefined ? file.text : undefined;
+                return fileName in files ? files[fileName].text : undefined;
             }
         };
     }
@@ -162,7 +161,7 @@ namespace ts {
         return false;
     }
 
-    function checkCache<T>(caption: string, program: Program, fileName: string, expectedContent: Map<string, T>, getCache: (f: SourceFile) => Map<string, T>, entryChecker: (expected: T, original: T) => boolean): void {
+    function checkCache<T>(caption: string, program: Program, fileName: string, expectedContent: Map<T>, getCache: (f: SourceFile) => Map<T>, entryChecker: (expected: T, original: T) => boolean): void {
         const file = program.getSourceFile(fileName);
         assert.isTrue(file !== undefined, `cannot find file ${fileName}`);
         const cache = getCache(file);
@@ -171,15 +170,15 @@ namespace ts {
         }
         else {
             assert.isTrue(cache !== undefined, `expected ${caption} to be set`);
-            assert.isTrue(mapsAreEqual(expectedContent, cache, entryChecker), `contents of ${caption} did not match the expected contents.`);
+            assert.isTrue(equalOwnProperties(expectedContent, cache, entryChecker), `contents of ${caption} did not match the expected contents.`);
         }
     }
 
-    function checkResolvedModulesCache(program: Program, fileName: string, expectedContent: Map<string, ResolvedModule>): void {
+    function checkResolvedModulesCache(program: Program, fileName: string, expectedContent: Map<ResolvedModule>): void {
         checkCache("resolved modules", program, fileName, expectedContent, f => f.resolvedModules, checkResolvedModule);
     }
 
-    function checkResolvedTypeDirectivesCache(program: Program, fileName: string, expectedContent: Map<string, ResolvedTypeReferenceDirective>): void {
+    function checkResolvedTypeDirectivesCache(program: Program, fileName: string, expectedContent: Map<ResolvedTypeReferenceDirective>): void {
         checkCache("resolved type directives", program, fileName, expectedContent, f => f.resolvedTypeReferenceDirectiveNames, checkResolvedTypeDirective);
     }
 
@@ -290,7 +289,7 @@ namespace ts {
             const options: CompilerOptions = { target };
 
             const program_1 = newProgram(files, ["a.ts"], options);
-            checkResolvedModulesCache(program_1, "a.ts", mapOfMapLike({ "b": createResolvedModule("b.ts") }));
+            checkResolvedModulesCache(program_1, "a.ts", createMap({ "b": createResolvedModule("b.ts") }));
             checkResolvedModulesCache(program_1, "b.ts", undefined);
 
             const program_2 = updateProgram(program_1, ["a.ts"], options, files => {
@@ -299,7 +298,7 @@ namespace ts {
             assert.isTrue(program_1.structureIsReused);
 
             // content of resolution cache should not change
-            checkResolvedModulesCache(program_1, "a.ts", mapOfMapLike({ "b": createResolvedModule("b.ts") }));
+            checkResolvedModulesCache(program_1, "a.ts", createMap({ "b": createResolvedModule("b.ts") }));
             checkResolvedModulesCache(program_1, "b.ts", undefined);
 
             // imports has changed - program is not reused
@@ -316,7 +315,7 @@ namespace ts {
                 files[0].text = files[0].text.updateImportsAndExports(newImports);
             });
             assert.isTrue(!program_3.structureIsReused);
-            checkResolvedModulesCache(program_4, "a.ts", mapOfMapLike({ "b": createResolvedModule("b.ts"), "c": undefined }));
+            checkResolvedModulesCache(program_4, "a.ts", createMap({ "b": createResolvedModule("b.ts"), "c": undefined }));
         });
 
         it("resolved type directives cache follows type directives", () => {
@@ -327,7 +326,7 @@ namespace ts {
             const options: CompilerOptions = { target, typeRoots: ["/types"] };
 
             const program_1 = newProgram(files, ["/a.ts"], options);
-            checkResolvedTypeDirectivesCache(program_1, "/a.ts", mapOfMapLike({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
+            checkResolvedTypeDirectivesCache(program_1, "/a.ts", createMap({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
             checkResolvedTypeDirectivesCache(program_1, "/types/typedefs/index.d.ts", undefined);
 
             const program_2 = updateProgram(program_1, ["/a.ts"], options, files => {
@@ -336,7 +335,7 @@ namespace ts {
             assert.isTrue(program_1.structureIsReused);
 
             // content of resolution cache should not change
-            checkResolvedTypeDirectivesCache(program_1, "/a.ts", mapOfMapLike({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
+            checkResolvedTypeDirectivesCache(program_1, "/a.ts", createMap({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
             checkResolvedTypeDirectivesCache(program_1, "/types/typedefs/index.d.ts", undefined);
 
             // type reference directives has changed - program is not reused
@@ -354,7 +353,7 @@ namespace ts {
                 files[0].text = files[0].text.updateReferences(newReferences);
             });
             assert.isTrue(!program_3.structureIsReused);
-            checkResolvedTypeDirectivesCache(program_1, "/a.ts", mapOfMapLike({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
+            checkResolvedTypeDirectivesCache(program_1, "/a.ts", createMap({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
         });
     });
 
diff --git a/src/harness/unittests/session.ts b/src/harness/unittests/session.ts
index 53f3ec3deb287..dd9efe51a4aee 100644
--- a/src/harness/unittests/session.ts
+++ b/src/harness/unittests/session.ts
@@ -159,6 +159,9 @@ namespace ts.server {
             it("should not throw when commands are executed with invalid arguments", () => {
                 let i = 0;
                 for (const name in CommandNames) {
+                    if (!Object.prototype.hasOwnProperty.call(CommandNames, name)) {
+                        continue;
+                    }
                     const req: protocol.Request = {
                         command: name,
                         seq: i,
@@ -411,15 +414,15 @@ namespace ts.server {
         class InProcClient {
             private server: InProcSession;
             private seq = 0;
-            private callbacks = createMap<number, (resp: protocol.Response) => void>();
-            private eventHandlers = createMap<string, (args: any) => void>();
+            private callbacks = createMap<(resp: protocol.Response) => void>();
+            private eventHandlers = createMap<(args: any) => void>();
 
             handle(msg: protocol.Message): void {
                 if (msg.type === "response") {
                     const response = <protocol.Response>msg;
-                    const callback = tryDelete(this.callbacks, response.request_seq);
-                    if (callback !== undefined) {
-                        callback(response);
+                    if (response.request_seq in this.callbacks) {
+                        this.callbacks[response.request_seq](response);
+                        delete this.callbacks[response.request_seq];
                     }
                 }
                 else if (msg.type === "event") {
@@ -429,14 +432,13 @@ namespace ts.server {
             }
 
             emit(name: string, args: any): void {
-                const handler = this.eventHandlers.get(name);
-                if (handler !== undefined) {
-                    handler(args);
+                if (name in this.eventHandlers) {
+                    this.eventHandlers[name](args);
                 }
             }
 
             on(name: string, handler: (args: any) => void): void {
-                this.eventHandlers.set(name, handler);
+                this.eventHandlers[name] = handler;
             }
 
             connect(session: InProcSession): void {
@@ -454,7 +456,7 @@ namespace ts.server {
                     command,
                     arguments: args
                 });
-                this.callbacks.set(this.seq, callback);
+                this.callbacks[this.seq] = callback;
             }
         };
 
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index 8972da33bb1eb..5ac1892157856 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -249,10 +249,10 @@ namespace ts.projectSystem {
         return entry;
     }
 
-    export function checkMapKeys(caption: string, map: Map<string, any>, expectedKeys: string[]) {
-        assert.equal(mapSize(map), expectedKeys.length, `${caption}: incorrect size of map`);
+    export function checkMapKeys(caption: string, map: Map<any>, expectedKeys: string[]) {
+        assert.equal(reduceProperties(map, count => count + 1, 0), expectedKeys.length, `${caption}: incorrect size of map`);
         for (const name of expectedKeys) {
-            assert.isTrue(map.has(name), `${caption} is expected to contain ${name}, actual keys: ${keysOfMap(map)}`);
+            assert.isTrue(name in map, `${caption} is expected to contain ${name}, actual keys: ${Object.keys(map)}`);
         }
     }
 
@@ -298,28 +298,38 @@ namespace ts.projectSystem {
     }
 
     export class Callbacks {
-        private map = createMap<number, TimeOutCallback>();
+        private map: { [n: number]: TimeOutCallback } = {};
         private nextId = 1;
 
         register(cb: (...args: any[]) => void, args: any[]) {
             const timeoutId = this.nextId;
             this.nextId++;
-            this.map.set(timeoutId, cb.bind(undefined, ...args));
+            this.map[timeoutId] = cb.bind(undefined, ...args);
             return timeoutId;
         }
         unregister(id: any) {
             if (typeof id === "number") {
-                this.map.delete(id);
+                delete this.map[id];
             }
         }
 
         count() {
-            return mapSize(this.map);
+            let n = 0;
+            for (const _ in this.map) {
+                // TODO: GH#11734
+                _;
+                n++;
+            }
+            return n;
         }
 
         invoke() {
-            this.map.forEach(callback => { callback(); });
-            this.map.clear();
+            for (const id in this.map) {
+                if (hasProperty(this.map, id)) {
+                    this.map[id]();
+                }
+            }
+            this.map = {};
         }
     }
 
@@ -335,9 +345,8 @@ namespace ts.projectSystem {
         private timeoutCallbacks = new Callbacks();
         private immediateCallbacks = new Callbacks();
 
-        readonly watchedDirectories = createMap<string, { cb: DirectoryWatcherCallback, recursive: boolean }[]>();
-        readonly watchedFiles = createMap<string, FileWatcherCallback[]>();
-
+        readonly watchedDirectories = createMap<{ cb: DirectoryWatcherCallback, recursive: boolean }[]>();
+        readonly watchedFiles = createMap<FileWatcherCallback[]>();
 
         private filesOrFolders: FileOrFolder[];
 
@@ -432,7 +441,7 @@ namespace ts.projectSystem {
 
         triggerDirectoryWatcherCallback(directoryName: string, fileName: string): void {
             const path = this.toPath(directoryName);
-            const callbacks = this.watchedDirectories.get(path);
+            const callbacks = this.watchedDirectories[path];
             if (callbacks) {
                 for (const callback of callbacks) {
                     callback.cb(fileName);
@@ -442,7 +451,7 @@ namespace ts.projectSystem {
 
         triggerFileWatcherCallback(fileName: string, removed?: boolean): void {
             const path = this.toPath(fileName);
-            const callbacks = this.watchedFiles.get(path);
+            const callbacks = this.watchedFiles[path];
             if (callbacks) {
                 for (const callback of callbacks) {
                     callback(path, removed);
diff --git a/src/harness/unittests/typingsInstaller.ts b/src/harness/unittests/typingsInstaller.ts
index e101b932ef9f3..356992d57176e 100644
--- a/src/harness/unittests/typingsInstaller.ts
+++ b/src/harness/unittests/typingsInstaller.ts
@@ -955,7 +955,7 @@ namespace ts.projectSystem {
                 content: ""
             };
             const host = createServerHost([f]);
-            const cache = createMap<string, string>();
+            const cache = createMap<string>();
             for (const name of JsTyping.nodeCoreModuleList) {
                 const result = JsTyping.discoverTypings(host, [f.path], getDirectoryPath(<Path>f.path), /*safeListPath*/ undefined, cache, { enableAutoDiscovery: true }, [name, "somename"]);
                 assert.deepEqual(result.newTypingNames.sort(), ["node", "somename"]);
@@ -972,7 +972,7 @@ namespace ts.projectSystem {
                 content: ""
             };
             const host = createServerHost([f, node]);
-            const cache = mapOfMapLike({ "node": node.path });
+            const cache = createMap<string>({ "node": node.path });
             const result = JsTyping.discoverTypings(host, [f.path], getDirectoryPath(<Path>f.path), /*safeListPath*/ undefined, cache, { enableAutoDiscovery: true }, ["fs", "bar"]);
             assert.deepEqual(result.cachedTypingPaths, [node.path]);
             assert.deepEqual(result.newTypingNames, ["bar"]);
diff --git a/src/server/builder.ts b/src/server/builder.ts
index 59948f32df6f5..548a3ac854c0e 100644
--- a/src/server/builder.ts
+++ b/src/server/builder.ts
@@ -346,26 +346,25 @@ namespace ts.server {
 
             // Use slice to clone the array to avoid manipulating in place
             const queue = fileInfo.referencedBy.slice(0);
-            const fileNameSet = createMap<string, ScriptInfo>();
-            fileNameSet.set(scriptInfo.fileName, scriptInfo);
+            const fileNameSet = createMap<ScriptInfo>();
+            fileNameSet[scriptInfo.fileName] = scriptInfo;
             while (queue.length > 0) {
                 const processingFileInfo = queue.pop();
                 if (processingFileInfo.updateShapeSignature() && processingFileInfo.referencedBy.length > 0) {
                     for (const potentialFileInfo of processingFileInfo.referencedBy) {
-                        if (!fileNameSet.get(potentialFileInfo.scriptInfo.fileName)) {
+                        if (!fileNameSet[potentialFileInfo.scriptInfo.fileName]) {
                             queue.push(potentialFileInfo);
                         }
                     }
                 }
-                fileNameSet.set(processingFileInfo.scriptInfo.fileName, processingFileInfo.scriptInfo);
+                fileNameSet[processingFileInfo.scriptInfo.fileName] = processingFileInfo.scriptInfo;
             }
-
             const result: string[] = [];
-            fileNameSet.forEach((scriptInfo, fileName) => {
-                if (shouldEmitFile(scriptInfo)) {
+            for (const fileName in fileNameSet) {
+                if (shouldEmitFile(fileNameSet[fileName])) {
                     result.push(fileName);
                 }
-            });
+            }
             return result;
         }
     }
diff --git a/src/server/client.ts b/src/server/client.ts
index f4912025527e5..3b09a92675497 100644
--- a/src/server/client.ts
+++ b/src/server/client.ts
@@ -15,7 +15,7 @@ namespace ts.server {
 
     export class SessionClient implements LanguageService {
         private sequence: number = 0;
-        private lineMaps = ts.createMap<string, number[]>();
+        private lineMaps: ts.Map<number[]> = ts.createMap<number[]>();
         private messages: string[] = [];
         private lastRenameEntry: RenameEntry;
 
@@ -31,10 +31,10 @@ namespace ts.server {
         }
 
         private getLineMap(fileName: string): number[] {
-            let lineMap = this.lineMaps.get(fileName);
+            let lineMap = this.lineMaps[fileName];
             if (!lineMap) {
                 const scriptSnapshot = this.host.getScriptSnapshot(fileName);
-                lineMap = setAndReturn(this.lineMaps, fileName, ts.computeLineStarts(scriptSnapshot.getText(0, scriptSnapshot.getLength())));
+                lineMap = this.lineMaps[fileName] = ts.computeLineStarts(scriptSnapshot.getText(0, scriptSnapshot.getLength()));
             }
             return lineMap;
         }
@@ -140,7 +140,7 @@ namespace ts.server {
 
         changeFile(fileName: string, start: number, end: number, newText: string): void {
             // clear the line map after an edit
-            this.lineMaps.set(fileName, undefined);
+            this.lineMaps[fileName] = undefined;
 
             const lineOffset = this.positionToOneBasedLineOffset(fileName, start);
             const endLineOffset = this.positionToOneBasedLineOffset(fileName, end);
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index 109a372f8312a..6565940c22d08 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -17,23 +17,23 @@ namespace ts.server {
         (event: ProjectServiceEvent): void;
     }
 
-    function prepareConvertersForEnumLikeCompilerOptions(commandLineOptions: CommandLineOption[]): Map<string, Map<string, number>> {
-        const map = createMap<string, Map<string, number>>();
+    function prepareConvertersForEnumLikeCompilerOptions(commandLineOptions: CommandLineOption[]): Map<Map<number>> {
+        const map: Map<Map<number>> = createMap<Map<number>>();
         for (const option of commandLineOptions) {
             if (typeof option.type === "object") {
-                const optionMap = <Map<string, number>>option.type;
+                const optionMap = <Map<number>>option.type;
                 // verify that map contains only numbers
-                optionMap.forEach(value => {
-                    Debug.assert(typeof value  === "number");
-                });
-                map.set(option.name, optionMap);
+                for (const id in optionMap) {
+                    Debug.assert(typeof optionMap[id] === "number");
+                }
+                map[option.name] = optionMap;
             }
         }
         return map;
     }
 
     const compilerOptionConverters = prepareConvertersForEnumLikeCompilerOptions(optionDeclarations);
-    const indentStyle = mapOfMapLike({
+    const indentStyle = createMap({
         "none": IndentStyle.None,
         "block": IndentStyle.Block,
         "smart": IndentStyle.Smart
@@ -41,20 +41,20 @@ namespace ts.server {
 
     export function convertFormatOptions(protocolOptions: protocol.FormatCodeSettings): FormatCodeSettings {
         if (typeof protocolOptions.indentStyle === "string") {
-            protocolOptions.indentStyle = indentStyle.get(protocolOptions.indentStyle.toLowerCase());
+            protocolOptions.indentStyle = indentStyle[protocolOptions.indentStyle.toLowerCase()];
             Debug.assert(protocolOptions.indentStyle !== undefined);
         }
         return <any>protocolOptions;
     }
 
     export function convertCompilerOptions(protocolOptions: protocol.ExternalProjectCompilerOptions): CompilerOptions & protocol.CompileOnSaveMixin {
-        forEachKeyInMap(compilerOptionConverters, id => {
+        for (const id in compilerOptionConverters) {
             const propertyValue = protocolOptions[id];
             if (typeof propertyValue === "string") {
-                const mappedValues = compilerOptionConverters.get(id);
-                protocolOptions[id] = mappedValues.get(propertyValue.toLowerCase());
+                const mappedValues = compilerOptionConverters[id];
+                protocolOptions[id] = mappedValues[propertyValue.toLowerCase()];
             }
-        });
+        }
         return <any>protocolOptions;
     }
 
@@ -159,24 +159,23 @@ namespace ts.server {
         /**
          * a path to directory watcher map that detects added tsconfig files
          **/
-        private readonly directoryWatchersForTsconfig = createMap<string, FileWatcher>();
+        private readonly directoryWatchersForTsconfig: Map<FileWatcher> = createMap<FileWatcher>();
         /**
          * count of how many projects are using the directory watcher.
          * If the number becomes 0 for a watcher, then we should close it.
          **/
-        private readonly directoryWatchersRefCount = createMap<string, number>();
+        private readonly directoryWatchersRefCount: Map<number> = createMap<number>();
 
         constructor(private readonly projectService: ProjectService) {
         }
 
         stopWatchingDirectory(directory: string) {
             // if the ref count for this directory watcher drops to 0, it's time to close it
-            const refCount = this.directoryWatchersRefCount.get(directory) - 1;
-            this.directoryWatchersRefCount.set(directory, refCount);
-            if (refCount === 0) {
+            this.directoryWatchersRefCount[directory]--;
+            if (this.directoryWatchersRefCount[directory] === 0) {
                 this.projectService.logger.info(`Close directory watcher for: ${directory}`);
-                this.directoryWatchersForTsconfig.get(directory).close();
-                this.directoryWatchersForTsconfig.delete(directory);
+                this.directoryWatchersForTsconfig[directory].close();
+                delete this.directoryWatchersForTsconfig[directory];
             }
         }
 
@@ -184,13 +183,13 @@ namespace ts.server {
             let currentPath = getDirectoryPath(fileName);
             let parentPath = getDirectoryPath(currentPath);
             while (currentPath != parentPath) {
-                if (!this.directoryWatchersForTsconfig.get(currentPath)) {
+                if (!this.directoryWatchersForTsconfig[currentPath]) {
                     this.projectService.logger.info(`Add watcher for: ${currentPath}`);
-                    this.directoryWatchersForTsconfig.set(currentPath, this.projectService.host.watchDirectory(currentPath, callback));
-                    this.directoryWatchersRefCount.set(currentPath, 1);
+                    this.directoryWatchersForTsconfig[currentPath] = this.projectService.host.watchDirectory(currentPath, callback);
+                    this.directoryWatchersRefCount[currentPath] = 1;
                 }
                 else {
-                    modifyValue(this.directoryWatchersRefCount, currentPath, count => count + 1);
+                    this.directoryWatchersRefCount[currentPath] += 1;
                 }
                 project.directoriesWatchedForTsconfig.push(currentPath);
                 currentPath = parentPath;
@@ -212,7 +211,7 @@ namespace ts.server {
         /**
          * maps external project file name to list of config files that were the part of this project
          */
-        private readonly externalProjectToConfiguredProjectMap = createMap<string, NormalizedPath[]>();
+        private readonly externalProjectToConfiguredProjectMap: Map<NormalizedPath[]> = createMap<NormalizedPath[]>();
 
         /**
          * external projects (configuration and list of root files is not controlled by tsserver)
@@ -393,7 +392,7 @@ namespace ts.server {
             }
             else {
                 if (info && (!info.isOpen)) {
-                    // file has been changed which might affect the set of referenced files in projects that include
+                    // file has been changed which might affect the set of referenced files in projects that include 
                     // this file and set of inferred projects
                     info.reloadFromFile();
                     this.updateProjectGraphs(info.containingProjects);
@@ -412,7 +411,7 @@ namespace ts.server {
                 this.filenameToScriptInfo.remove(info.path);
                 this.lastDeletedFile = info;
 
-                // capture list of projects since detachAllProjects will wipe out original list
+                // capture list of projects since detachAllProjects will wipe out original list 
                 const containingProjects = info.containingProjects.slice();
 
                 info.detachAllProjects();
@@ -563,7 +562,7 @@ namespace ts.server {
                 const inferredProject = this.createInferredProjectWithRootFileIfNecessary(info);
                 if (!this.useSingleInferredProject) {
                     // if useOneInferredProject is not set then try to fixup ownership of open files
-                    // check 'defaultProject !== inferredProject' is necessary to handle cases
+                    // check 'defaultProject !== inferredProject' is necessary to handle cases 
                     // when creation inferred project for some file has added other open files into this project (i.e. as referenced files)
                     // we definitely don't want to delete the project that was just created
                     for (const f of this.openFiles) {
@@ -573,7 +572,7 @@ namespace ts.server {
                         }
                         const defaultProject = f.getDefaultProject();
                         if (isRootFileInInferredProject(info) && defaultProject !== inferredProject && inferredProject.containsScriptInfo(f)) {
-                            // open file used to be root in inferred project,
+                            // open file used to be root in inferred project, 
                             // this inferred project is different from the one we've just created for current file
                             // and new inferred project references this open file.
                             // We should delete old inferred project and attach open file to the new one
@@ -785,7 +784,7 @@ namespace ts.server {
                 files: parsedCommandLine.fileNames,
                 compilerOptions: parsedCommandLine.options,
                 configHasFilesProperty: config["files"] !== undefined,
-                wildcardDirectories: parsedCommandLine.wildcardDirectories,
+                wildcardDirectories: createMap(parsedCommandLine.wildcardDirectories),
                 typingOptions: parsedCommandLine.typingOptions,
                 compileOnSave: parsedCommandLine.compileOnSave
             };
@@ -844,7 +843,7 @@ namespace ts.server {
                 this.documentRegistry,
                 projectOptions.configHasFilesProperty,
                 projectOptions.compilerOptions,
-                mapOfMapLike(projectOptions.wildcardDirectories),
+                projectOptions.wildcardDirectories,
                 /*languageServiceEnabled*/ !sizeLimitExceeded,
                 projectOptions.compileOnSave === undefined ? false : projectOptions.compileOnSave);
 
@@ -902,7 +901,7 @@ namespace ts.server {
         private updateNonInferredProject<T>(project: ExternalProject | ConfiguredProject, newUncheckedFiles: T[], propertyReader: FilePropertyReader<T>, newOptions: CompilerOptions, newTypingOptions: TypingOptions, compileOnSave: boolean, configFileErrors: Diagnostic[]) {
             const oldRootScriptInfos = project.getRootScriptInfos();
             const newRootScriptInfos: ScriptInfo[] = [];
-            const newRootScriptInfoMap: Map<NormalizedPath, ScriptInfo> = createMap<string, ScriptInfo>();
+            const newRootScriptInfoMap: NormalizedPathMap<ScriptInfo> = createNormalizedPathMap<ScriptInfo>();
 
             let projectErrors: Diagnostic[];
             let rootFilesChanged = false;
@@ -930,7 +929,7 @@ namespace ts.server {
                 let toAdd: ScriptInfo[];
                 let toRemove: ScriptInfo[];
                 for (const oldFile of oldRootScriptInfos) {
-                    if (!newRootScriptInfoMap.has(oldFile.fileName)) {
+                    if (!newRootScriptInfoMap.contains(oldFile.fileName)) {
                         (toRemove || (toRemove = [])).push(oldFile);
                     }
                 }
@@ -947,7 +946,7 @@ namespace ts.server {
                 if (toAdd) {
                     for (const f of toAdd) {
                         if (f.isOpen && isRootFileInInferredProject(f)) {
-                            // if file is already root in some inferred project
+                            // if file is already root in some inferred project 
                             // - remove the file from that project and delete the project if necessary
                             const inferredProject = f.containingProjects[0];
                             inferredProject.removeFile(f);
@@ -1096,7 +1095,7 @@ namespace ts.server {
                     this.logger.info(`Host information ${args.hostInfo}`);
                 }
                 if (args.formatOptions) {
-                    mergeMapLikes(this.hostConfiguration.formatCodeOptions, convertFormatOptions(args.formatOptions));
+                    mergeMaps(this.hostConfiguration.formatCodeOptions, convertFormatOptions(args.formatOptions));
                     this.logger.info("Format host information updated");
                 }
             }
@@ -1218,7 +1217,7 @@ namespace ts.server {
                 for (const file of changedFiles) {
                     const scriptInfo = this.getScriptInfo(file.fileName);
                     Debug.assert(!!scriptInfo);
-                    // apply changes in reverse order
+                    // apply changes in reverse order 
                     for (let i = file.changes.length - 1; i >= 0; i--) {
                         const change = file.changes[i];
                         scriptInfo.editContent(change.span.start, change.span.start + change.span.length, change.newText);
@@ -1255,7 +1254,7 @@ namespace ts.server {
 
         closeExternalProject(uncheckedFileName: string, suppressRefresh = false): void {
             const fileName = toNormalizedPath(uncheckedFileName);
-            const configFiles = this.externalProjectToConfiguredProjectMap.get(fileName);
+            const configFiles = this.externalProjectToConfiguredProjectMap[fileName];
             if (configFiles) {
                 let shouldRefreshInferredProjects = false;
                 for (const configFile of configFiles) {
@@ -1263,7 +1262,7 @@ namespace ts.server {
                         shouldRefreshInferredProjects = true;
                     }
                 }
-                this.externalProjectToConfiguredProjectMap.delete(fileName);
+                delete this.externalProjectToConfiguredProjectMap[fileName];
                 if (shouldRefreshInferredProjects && !suppressRefresh) {
                     this.refreshInferredProjects();
                 }
@@ -1310,46 +1309,43 @@ namespace ts.server {
                 // close existing project and later we'll open a set of configured projects for these files
                 this.closeExternalProject(proj.projectFileName, /*suppressRefresh*/ true);
             }
-            else  {
-                const oldConfigFiles = this.externalProjectToConfiguredProjectMap.get(proj.projectFileName);
-                if (oldConfigFiles) {
-                    // this project used to include config files
-                    if (!tsConfigFiles) {
-                        // config files were removed from the project - close existing external project which in turn will close configured projects
-                        this.closeExternalProject(proj.projectFileName, /*suppressRefresh*/ true);
-                    }
-                    else {
-                        // project previously had some config files - compare them with new set of files and close all configured projects that correspond to unused files
-                        let iNew = 0;
-                        let iOld = 0;
-                        while (iNew < tsConfigFiles.length && iOld < oldConfigFiles.length) {
-                            const newConfig = tsConfigFiles[iNew];
-                            const oldConfig = oldConfigFiles[iOld];
-                            if (oldConfig < newConfig) {
-                                this.closeConfiguredProject(oldConfig);
-                                iOld++;
-                            }
-                            else if (oldConfig > newConfig) {
-                                iNew++;
-                            }
-                            else {
-                                // record existing config files so avoid extra add-refs
-                                (exisingConfigFiles || (exisingConfigFiles = [])).push(oldConfig);
-                                iOld++;
-                                iNew++;
-                            }
+            else if (this.externalProjectToConfiguredProjectMap[proj.projectFileName]) {
+                // this project used to include config files
+                if (!tsConfigFiles) {
+                    // config files were removed from the project - close existing external project which in turn will close configured projects
+                    this.closeExternalProject(proj.projectFileName, /*suppressRefresh*/ true);
+                }
+                else {
+                    // project previously had some config files - compare them with new set of files and close all configured projects that correspond to unused files
+                    const oldConfigFiles = this.externalProjectToConfiguredProjectMap[proj.projectFileName];
+                    let iNew = 0;
+                    let iOld = 0;
+                    while (iNew < tsConfigFiles.length && iOld < oldConfigFiles.length) {
+                        const newConfig = tsConfigFiles[iNew];
+                        const oldConfig = oldConfigFiles[iOld];
+                        if (oldConfig < newConfig) {
+                            this.closeConfiguredProject(oldConfig);
+                            iOld++;
                         }
-                        for (let i = iOld; i < oldConfigFiles.length; i++) {
-                            // projects for all remaining old config files should be closed
-                            this.closeConfiguredProject(oldConfigFiles[i]);
+                        else if (oldConfig > newConfig) {
+                            iNew++;
                         }
+                        else {
+                            // record existing config files so avoid extra add-refs
+                            (exisingConfigFiles || (exisingConfigFiles = [])).push(oldConfig);
+                            iOld++;
+                            iNew++;
+                        }
+                    }
+                    for (let i = iOld; i < oldConfigFiles.length; i++) {
+                        // projects for all remaining old config files should be closed
+                        this.closeConfiguredProject(oldConfigFiles[i]);
                     }
                 }
             }
-
             if (tsConfigFiles) {
                 // store the list of tsconfig files that belong to the external project
-                this.externalProjectToConfiguredProjectMap.set(proj.projectFileName, tsConfigFiles);
+                this.externalProjectToConfiguredProjectMap[proj.projectFileName] = tsConfigFiles;
                 for (const tsconfigFile of tsConfigFiles) {
                     let project = this.findConfiguredProjectByProjectName(tsconfigFile);
                     if (!project) {
@@ -1365,7 +1361,7 @@ namespace ts.server {
             }
             else {
                 // no config files - remove the item from the collection
-                this.externalProjectToConfiguredProjectMap.delete(proj.projectFileName);
+                delete this.externalProjectToConfiguredProjectMap[proj.projectFileName];
                 this.createAndAddExternalProject(proj.projectFileName, rootFiles, proj.options, proj.typingOptions);
             }
             this.refreshInferredProjects();
diff --git a/src/server/lsHost.ts b/src/server/lsHost.ts
index 26da70c53899d..628de71bb7a91 100644
--- a/src/server/lsHost.ts
+++ b/src/server/lsHost.ts
@@ -5,8 +5,8 @@
 namespace ts.server {
     export class LSHost implements ts.LanguageServiceHost, ModuleResolutionHost, ServerLanguageServiceHost {
         private compilationSettings: ts.CompilerOptions;
-        private readonly resolvedModuleNames = createFileMap<Map<string, ResolvedModuleWithFailedLookupLocations>>();
-        private readonly resolvedTypeReferenceDirectives = createFileMap<Map<string, ResolvedTypeReferenceDirectiveWithFailedLookupLocations>>();
+        private readonly resolvedModuleNames= createFileMap<Map<ResolvedModuleWithFailedLookupLocations>>();
+        private readonly resolvedTypeReferenceDirectives = createFileMap<Map<ResolvedTypeReferenceDirectiveWithFailedLookupLocations>>();
         private readonly getCanonicalFileName: (fileName: string) => string;
 
         private filesWithChangedSetOfUnresolvedImports: Path[];
@@ -54,7 +54,7 @@ namespace ts.server {
         private resolveNamesWithLocalCache<T extends { failedLookupLocations: string[] }, R>(
             names: string[],
             containingFile: string,
-            cache: ts.FileMap<Map<string, T>>,
+            cache: ts.FileMap<Map<T>>,
             loader: (name: string, containingFile: string, options: CompilerOptions, host: ModuleResolutionHost) => T,
             getResult: (s: T) => R,
             getResultFileName: (result: R) => string | undefined,
@@ -63,22 +63,22 @@ namespace ts.server {
             const path = toPath(containingFile, this.host.getCurrentDirectory(), this.getCanonicalFileName);
             const currentResolutionsInFile = cache.get(path);
 
-            const newResolutions = createMap<string, T>();
+            const newResolutions: Map<T> = createMap<T>();
             const resolvedModules: R[] = [];
             const compilerOptions = this.getCompilationSettings();
             const lastDeletedFileName = this.project.projectService.lastDeletedFile && this.project.projectService.lastDeletedFile.fileName;
 
             for (const name of names) {
                 // check if this is a duplicate entry in the list
-                let resolution = newResolutions.get(name);
+                let resolution = newResolutions[name];
                 if (!resolution) {
-                    const existingResolution = currentResolutionsInFile && currentResolutionsInFile.get(name);
+                    const existingResolution = currentResolutionsInFile && currentResolutionsInFile[name];
                     if (moduleResolutionIsValid(existingResolution)) {
                         // ok, it is safe to use existing name resolution results
                         resolution = existingResolution;
                     }
                     else {
-                        newResolutions.set(name, resolution = loader(name, containingFile, compilerOptions, this));
+                        newResolutions[name] = resolution = loader(name, containingFile, compilerOptions, this);
                     }
                     if (logChanges && this.filesWithChangedSetOfUnresolvedImports && !resolutionIsEqualTo(existingResolution, resolution)) {
                         this.filesWithChangedSetOfUnresolvedImports.push(path);
diff --git a/src/server/project.ts b/src/server/project.ts
index 92431c08543b4..5f4f8d4049027 100644
--- a/src/server/project.ts
+++ b/src/server/project.ts
@@ -104,7 +104,7 @@ namespace ts.server {
         /**
          * Set of files that was returned from the last call to getChangesSinceVersion.
          */
-        private lastReportedFileNames: Map<string, string>;
+        private lastReportedFileNames: Map<string>;
         /**
          * Last version that was reported.
          */
@@ -385,9 +385,9 @@ namespace ts.server {
             }
             let unresolvedImports: string[];
             if (file.resolvedModules) {
-                file.resolvedModules.forEach((resolvedModule, name) => {
+                for (const name in file.resolvedModules) {
                     // pick unresolved non-relative names
-                    if (!resolvedModule && !isExternalModuleNameRelative(name)) {
+                    if (!file.resolvedModules[name] && !isExternalModuleNameRelative(name)) {
                         // for non-scoped names extract part up-to the first slash
                         // for scoped names - extract up to the second slash
                         let trimmed = name.trim();
@@ -401,7 +401,7 @@ namespace ts.server {
                         (unresolvedImports || (unresolvedImports = [])).push(trimmed);
                         result.push(trimmed);
                     }
-                });
+                }
             }
             this.cachedUnresolvedImportsPerFile.set(file.path, unresolvedImports || emptyArray);
         }
@@ -427,7 +427,7 @@ namespace ts.server {
             }
 
             // 1. no changes in structure, no changes in unresolved imports - do nothing
-            // 2. no changes in structure, unresolved imports were changed - collect unresolved imports for all files
+            // 2. no changes in structure, unresolved imports were changed - collect unresolved imports for all files 
             // (can reuse cached imports for files that were not changed)
             // 3. new files were added/removed, but compilation settings stays the same - collect unresolved imports for all new/modified files
             // (can reuse cached imports for files that were not changed)
@@ -568,16 +568,16 @@ namespace ts.server {
 
                 const added: string[] = [];
                 const removed: string[] = [];
-                forEachKeyInMap(currentFiles, id => {
-                    if (!lastReportedFileNames.has(id)) {
+                for (const id in currentFiles) {
+                    if (!hasProperty(lastReportedFileNames, id)) {
                         added.push(id);
                     }
-                });
-                forEachKeyInMap(lastReportedFileNames, id => {
-                    if (!currentFiles.has(id)) {
+                }
+                for (const id in lastReportedFileNames) {
+                    if (!hasProperty(currentFiles, id)) {
                         removed.push(id);
                     }
-                });
+                }
                 this.lastReportedFileNames = currentFiles;
                 this.lastReportedVersion = this.projectStructureVersion;
                 return { info, changes: { added, removed }, projectErrors: this.projectErrors };
@@ -603,7 +603,7 @@ namespace ts.server {
             // We need to use a set here since the code can contain the same import twice,
             // but that will only be one dependency.
             // To avoid invernal conversion, the key of the referencedFiles map must be of type Path
-            const referencedFiles = createSet();
+            const referencedFiles = createMap<boolean>();
             if (sourceFile.imports && sourceFile.imports.length > 0) {
                 const checker: TypeChecker = this.program.getTypeChecker();
                 for (const importName of sourceFile.imports) {
@@ -611,7 +611,7 @@ namespace ts.server {
                     if (symbol && symbol.declarations && symbol.declarations[0]) {
                         const declarationSourceFile = symbol.declarations[0].getSourceFile();
                         if (declarationSourceFile) {
-                            referencedFiles.add(declarationSourceFile.path);
+                            referencedFiles[declarationSourceFile.path] = true;
                         }
                     }
                 }
@@ -623,24 +623,26 @@ namespace ts.server {
             if (sourceFile.referencedFiles && sourceFile.referencedFiles.length > 0) {
                 for (const referencedFile of sourceFile.referencedFiles) {
                     const referencedPath = toPath(referencedFile.fileName, currentDirectory, getCanonicalFileName);
-                    referencedFiles.add(referencedPath);
+                    referencedFiles[referencedPath] = true;
                 }
             }
 
             // Handle type reference directives
             if (sourceFile.resolvedTypeReferenceDirectiveNames) {
-                sourceFile.resolvedTypeReferenceDirectiveNames.forEach(resolvedTypeReferenceDirective => {
+                for (const typeName in sourceFile.resolvedTypeReferenceDirectiveNames) {
+                    const resolvedTypeReferenceDirective = sourceFile.resolvedTypeReferenceDirectiveNames[typeName];
                     if (!resolvedTypeReferenceDirective) {
-                        return;
+                        continue;
                     }
 
                     const fileName = resolvedTypeReferenceDirective.resolvedFileName;
                     const typeFilePath = toPath(fileName, currentDirectory, getCanonicalFileName);
-                    referencedFiles.add(typeFilePath);
-                });
+                    referencedFiles[typeFilePath] = true;
+                }
             }
 
-            return filterSetToArray(referencedFiles, file => this.projectService.host.fileExists(file)) as Path[];
+            const allFileNames = map(Object.keys(referencedFiles), key => <Path>key);
+            return filter(allFileNames, file => this.projectService.host.fileExists(file));
         }
 
         // remove a root file from project
@@ -711,7 +713,7 @@ namespace ts.server {
         private typingOptions: TypingOptions;
         private projectFileWatcher: FileWatcher;
         private directoryWatcher: FileWatcher;
-        private directoriesWatchedForWildcards: Map<string, FileWatcher>;
+        private directoriesWatchedForWildcards: Map<FileWatcher>;
         private typeRootsWatchers: FileWatcher[];
 
         /** Used for configured projects which may have multiple open roots */
@@ -722,7 +724,7 @@ namespace ts.server {
             documentRegistry: ts.DocumentRegistry,
             hasExplicitListOfFiles: boolean,
             compilerOptions: CompilerOptions,
-            private wildcardDirectories: Map<string, WatchDirectoryFlags>,
+            private wildcardDirectories: Map<WatchDirectoryFlags>,
             languageServiceEnabled: boolean,
             public compileOnSaveEnabled: boolean) {
             super(ProjectKind.Configured, projectService, documentRegistry, hasExplicitListOfFiles, languageServiceEnabled, compilerOptions, compileOnSaveEnabled);
@@ -777,19 +779,18 @@ namespace ts.server {
                 return;
             }
             const configDirectoryPath = getDirectoryPath(this.configFileName);
-
-            this.directoriesWatchedForWildcards = createMap<string, FileWatcher>();
-            this.wildcardDirectories.forEach((flag, directory) => {
+            this.directoriesWatchedForWildcards = reduceProperties(this.wildcardDirectories, (watchers, flag, directory) => {
                 if (comparePaths(configDirectoryPath, directory, ".", !this.projectService.host.useCaseSensitiveFileNames) !== Comparison.EqualTo) {
                     const recursive = (flag & WatchDirectoryFlags.Recursive) !== 0;
                     this.projectService.logger.info(`Add ${recursive ? "recursive " : ""}watcher for: ${directory}`);
-                    this.directoriesWatchedForWildcards.set(directory, this.projectService.host.watchDirectory(
+                    watchers[directory] = this.projectService.host.watchDirectory(
                         directory,
                         path => callback(this, path),
                         recursive
-                    ));
+                    );
                 }
-            });
+                return watchers;
+            }, <Map<FileWatcher>>{});
         }
 
         stopWatchingDirectory() {
@@ -813,7 +814,9 @@ namespace ts.server {
                 this.typeRootsWatchers = undefined;
             }
 
-            this.directoriesWatchedForWildcards.forEach(watcher => { watcher.close(); });
+            for (const id in this.directoriesWatchedForWildcards) {
+                this.directoriesWatchedForWildcards[id].close();
+            }
             this.directoriesWatchedForWildcards = undefined;
 
             this.stopWatchingDirectory();
diff --git a/src/server/scriptInfo.ts b/src/server/scriptInfo.ts
index fa9eac0e8e399..84649863a7b3a 100644
--- a/src/server/scriptInfo.ts
+++ b/src/server/scriptInfo.ts
@@ -95,7 +95,7 @@ namespace ts.server {
                 if (!this.formatCodeSettings) {
                     this.formatCodeSettings = getDefaultFormatCodeSettings(this.host);
                 }
-                mergeMapLikes(this.formatCodeSettings, formatSettings);
+                mergeMaps(this.formatCodeSettings, formatSettings);
             }
         }
 
diff --git a/src/server/session.ts b/src/server/session.ts
index 4c9990f22843b..545701f1449fa 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -1351,7 +1351,7 @@ namespace ts.server {
             return { response, responseRequired: true };
         }
 
-        private handlers = mapOfMapLike<(request: protocol.Request) => { response?: any, responseRequired?: boolean }>({
+        private handlers = createMap<(request: protocol.Request) => { response?: any, responseRequired?: boolean }>({
             [CommandNames.OpenExternalProject]: (request: protocol.OpenExternalProjectRequest) => {
                 this.projectService.openExternalProject(request.arguments);
                 // TODO: report errors
@@ -1597,14 +1597,14 @@ namespace ts.server {
         });
 
         public addProtocolHandler(command: string, handler: (request: protocol.Request) => { response?: any, responseRequired: boolean }) {
-            if (this.handlers.has(command)) {
+            if (command in this.handlers) {
                 throw new Error(`Protocol handler already exists for command "${command}"`);
             }
-            this.handlers.set(command, handler);
+            this.handlers[command] = handler;
         }
 
         public executeCommand(request: protocol.Request): { response?: any, responseRequired?: boolean } {
-            const handler = this.handlers.get(request.command);
+            const handler = this.handlers[request.command];
             if (handler) {
                 return handler(request);
             }
diff --git a/src/server/tsconfig.library.json b/src/server/tsconfig.library.json
index b5b3bf2328c23..e269629b55898 100644
--- a/src/server/tsconfig.library.json
+++ b/src/server/tsconfig.library.json
@@ -18,7 +18,7 @@
         "utilities.ts",
         "scriptVersionCache.ts",
         "scriptInfo.ts",
-        "lsHost.ts",
+        "lshost.ts",
         "typingsCache.ts",
         "project.ts",
         "editorServices.ts",
diff --git a/src/server/typingsCache.ts b/src/server/typingsCache.ts
index 399a0788c4744..9013622e24ada 100644
--- a/src/server/typingsCache.ts
+++ b/src/server/typingsCache.ts
@@ -31,22 +31,21 @@ namespace ts.server {
         if ((arr1 || emptyArray).length === 0 && (arr2 || emptyArray).length === 0) {
             return true;
         }
-        const set = createMap<string, boolean>();
+        const set: Map<boolean> = createMap<boolean>();
         let unique = 0;
 
         for (const v of arr1) {
-            if (set.get(v) !== true) {
-                set.set(v, true);
+            if (set[v] !== true) {
+                set[v] = true;
                 unique++;
             }
         }
         for (const v of arr2) {
-            const isSet = set.get(v);
-            if (isSet === undefined) {
+            if (!hasProperty(set, v)) {
                 return false;
             }
-            if (isSet === true) {
-                set.set(v, false);
+            if (set[v] === true) {
+                set[v] = false;
                 unique--;
             }
         }
@@ -72,7 +71,7 @@ namespace ts.server {
     }
 
     export class TypingsCache {
-        private readonly perProjectCache = createMap<string, TypingsCacheEntry>();
+        private readonly perProjectCache: Map<TypingsCacheEntry> = createMap<TypingsCacheEntry>();
 
         constructor(private readonly installer: ITypingsInstaller) {
         }
@@ -84,7 +83,7 @@ namespace ts.server {
                 return <any>emptyArray;
             }
 
-            const entry = this.perProjectCache.get(project.getProjectName());
+            const entry = this.perProjectCache[project.getProjectName()];
             const result: SortedReadonlyArray<string> = entry ? entry.typings : <any>emptyArray;
             if (forceRefresh ||
                 !entry ||
@@ -93,13 +92,13 @@ namespace ts.server {
                 unresolvedImportsChanged(unresolvedImports, entry.unresolvedImports)) {
                 // Note: entry is now poisoned since it does not really contain typings for a given combination of compiler options\typings options.
                 // instead it acts as a placeholder to prevent issuing multiple requests
-                this.perProjectCache.set(project.getProjectName(), {
+                this.perProjectCache[project.getProjectName()] = {
                     compilerOptions: project.getCompilerOptions(),
                     typingOptions,
                     typings: result,
                     unresolvedImports,
                     poisoned: true
-                });
+                };
                 // something has been changed, issue a request to update typings
                 this.installer.enqueueInstallTypingsRequest(project, typingOptions, unresolvedImports);
             }
@@ -107,21 +106,21 @@ namespace ts.server {
         }
 
         updateTypingsForProject(projectName: string, compilerOptions: CompilerOptions, typingOptions: TypingOptions, unresolvedImports: SortedReadonlyArray<string>, newTypings: string[]) {
-            this.perProjectCache.set(projectName, {
+            this.perProjectCache[projectName] = {
                 compilerOptions,
                 typingOptions,
                 typings: toSortedReadonlyArray(newTypings),
                 unresolvedImports,
                 poisoned: false
-            });
+            };
         }
 
         deleteTypingsForProject(projectName: string) {
-            this.perProjectCache.delete(projectName);
+            delete this.perProjectCache[projectName];
         }
 
         onProjectClosed(project: Project) {
-            this.perProjectCache.delete(project.getProjectName());
+            delete this.perProjectCache[project.getProjectName()];
             this.installer.onProjectClosed(project);
         }
     }
diff --git a/src/server/typingsInstaller/typingsInstaller.ts b/src/server/typingsInstaller/typingsInstaller.ts
index 18c16b0d90ca5..df043fc26ae06 100644
--- a/src/server/typingsInstaller/typingsInstaller.ts
+++ b/src/server/typingsInstaller/typingsInstaller.ts
@@ -78,10 +78,10 @@ namespace ts.server.typingsInstaller {
     };
 
     export abstract class TypingsInstaller {
-        private readonly packageNameToTypingLocation = createMap<string, string>();
-        private readonly missingTypingsSet = createSet();
-        private readonly knownCachesSet = createSet();
-        private readonly projectWatchers = createMap<string, FileWatcher[]>();
+        private readonly packageNameToTypingLocation: Map<string> = createMap<string>();
+        private readonly missingTypingsSet: Map<true> = createMap<true>();
+        private readonly knownCachesSet: Map<true> = createMap<true>();
+        private readonly projectWatchers: Map<FileWatcher[]> = createMap<FileWatcher[]>();
         readonly pendingRunRequests: PendingRequest[] = [];
 
         private installRunCount = 1;
@@ -111,7 +111,7 @@ namespace ts.server.typingsInstaller {
             if (this.log.isEnabled()) {
                 this.log.writeLine(`Closing file watchers for project '${projectName}'`);
             }
-            const watchers = this.projectWatchers.get(projectName);
+            const watchers = this.projectWatchers[projectName];
             if (!watchers) {
                 if (this.log.isEnabled()) {
                     this.log.writeLine(`No watchers are registered for project '${projectName}'`);
@@ -122,7 +122,7 @@ namespace ts.server.typingsInstaller {
                 w.close();
             }
 
-            this.projectWatchers.delete(projectName);
+            delete this.projectWatchers[projectName];
 
             if (this.log.isEnabled()) {
                 this.log.writeLine(`Closing file watchers for project '${projectName}' - done.`);
@@ -176,7 +176,7 @@ namespace ts.server.typingsInstaller {
             if (this.log.isEnabled()) {
                 this.log.writeLine(`Processing cache location '${cacheLocation}'`);
             }
-            if (this.knownCachesSet.has(cacheLocation)) {
+            if (this.knownCachesSet[cacheLocation]) {
                 if (this.log.isEnabled()) {
                     this.log.writeLine(`Cache location was already processed...`);
                 }
@@ -202,7 +202,7 @@ namespace ts.server.typingsInstaller {
                         if (!typingFile) {
                             continue;
                         }
-                        const existingTypingFile = this.packageNameToTypingLocation.get(packageName);
+                        const existingTypingFile = this.packageNameToTypingLocation[packageName];
                         if (existingTypingFile === typingFile) {
                             continue;
                         }
@@ -214,14 +214,14 @@ namespace ts.server.typingsInstaller {
                         if (this.log.isEnabled()) {
                             this.log.writeLine(`Adding entry into typings cache: '${packageName}' => '${typingFile}'`);
                         }
-                        this.packageNameToTypingLocation.set(packageName, typingFile);
+                        this.packageNameToTypingLocation[packageName] = typingFile;
                     }
                 }
             }
             if (this.log.isEnabled()) {
                 this.log.writeLine(`Finished processing cache location '${cacheLocation}'`);
             }
-            this.knownCachesSet.add(cacheLocation);
+            this.knownCachesSet[cacheLocation] = true;
         }
 
         private filterTypings(typingsToInstall: string[]) {
@@ -230,7 +230,7 @@ namespace ts.server.typingsInstaller {
             }
             const result: string[] = [];
             for (const typing of typingsToInstall) {
-                if (this.missingTypingsSet.has(typing)) {
+                if (this.missingTypingsSet[typing]) {
                     continue;
                 }
                 const validationResult = validatePackageName(typing);
@@ -239,7 +239,7 @@ namespace ts.server.typingsInstaller {
                 }
                 else {
                     // add typing name to missing set so we won't process it again
-                    this.missingTypingsSet.add(typing);
+                    this.missingTypingsSet[typing] = true;
                     if (this.log.isEnabled()) {
                         switch (validationResult) {
                             case PackageNameValidationResult.EmptyName:
@@ -296,20 +296,20 @@ namespace ts.server.typingsInstaller {
                 if (this.log.isEnabled()) {
                     this.log.writeLine(`Requested to install typings ${JSON.stringify(typingsToInstall)}, installed typings ${JSON.stringify(installedTypings)}`);
                 }
-                const installedPackages = createSet();
+                const installedPackages: Map<true> = createMap<true>();
                 const installedTypingFiles: string[] = [];
                 for (const t of installedTypings) {
                     const packageName = getBaseFileName(t);
                     if (!packageName) {
                         continue;
                     }
-                    installedPackages.add(packageName);
+                    installedPackages[packageName] = true;
                     const typingFile = typingToFileName(cachePath, packageName, this.installTypingHost);
                     if (!typingFile) {
                         continue;
                     }
-                    if (!this.packageNameToTypingLocation.get(packageName)) {
-                        this.packageNameToTypingLocation.set(packageName, typingFile);
+                    if (!this.packageNameToTypingLocation[packageName]) {
+                        this.packageNameToTypingLocation[packageName] = typingFile;
                     }
                     installedTypingFiles.push(typingFile);
                 }
@@ -317,11 +317,11 @@ namespace ts.server.typingsInstaller {
                     this.log.writeLine(`Installed typing files ${JSON.stringify(installedTypingFiles)}`);
                 }
                 for (const toInstall of typingsToInstall) {
-                    if (!installedPackages.has(toInstall)) {
+                    if (!installedPackages[toInstall]) {
                         if (this.log.isEnabled()) {
                             this.log.writeLine(`New missing typing package '${toInstall}'`);
                         }
-                        this.missingTypingsSet.add(toInstall);
+                        this.missingTypingsSet[toInstall] = true;
                     }
                 }
 
@@ -395,7 +395,7 @@ namespace ts.server.typingsInstaller {
                 });
                 watchers.push(w);
             }
-            this.projectWatchers.set(projectName, watchers);
+            this.projectWatchers[projectName] = watchers;
         }
 
         private createSetTypings(request: DiscoverTypings, typings: string[]): SetTypings {
diff --git a/src/server/utilities.ts b/src/server/utilities.ts
index 8cf2fbfe24218..8806b759e3f8d 100644
--- a/src/server/utilities.ts
+++ b/src/server/utilities.ts
@@ -91,7 +91,7 @@ namespace ts.server {
         };
     }
 
-    export function mergeMapLikes(target: MapLike<any>, source: MapLike <any>): void {
+    export function mergeMaps(target: MapLike<any>, source: MapLike <any>): void {
         for (const key in source) {
             if (hasProperty(source, key)) {
                 target[key] = source[key];
@@ -132,6 +132,32 @@ namespace ts.server {
         return <NormalizedPath>fileName;
     }
 
+    export interface NormalizedPathMap<T> {
+        get(path: NormalizedPath): T;
+        set(path: NormalizedPath, value: T): void;
+        contains(path: NormalizedPath): boolean;
+        remove(path: NormalizedPath): void;
+    }
+
+    export function createNormalizedPathMap<T>(): NormalizedPathMap<T> {
+/* tslint:disable:no-null-keyword */
+        const map: Map<T> = Object.create(null);
+/* tslint:enable:no-null-keyword */
+        return {
+            get(path) {
+                return map[path];
+            },
+            set(path, value) {
+                map[path] = value;
+            },
+            contains(path) {
+                return hasProperty(map, path);
+            },
+            remove(path) {
+                delete map[path];
+            }
+        };
+    }
     function throwLanguageServiceIsDisabledError(): never {
         throw new Error("LanguageService is disabled");
     }
@@ -204,7 +230,7 @@ namespace ts.server {
          * these fields can be present in the project file
          **/
         files?: string[];
-        wildcardDirectories?: MapLike<WatchDirectoryFlags>;
+        wildcardDirectories?: Map<WatchDirectoryFlags>;
         compilerOptions?: CompilerOptions;
         typingOptions?: TypingOptions;
         compileOnSave?: boolean;
@@ -225,22 +251,21 @@ namespace ts.server {
     }
 
     export class ThrottledOperations {
-        private pendingTimeouts = createMap<string, any>();
+        private pendingTimeouts: Map<any> = createMap<any>();
         constructor(private readonly host: ServerHost) {
         }
 
         public schedule(operationId: string, delay: number, cb: () => void) {
-            const pendingTimeout = this.pendingTimeouts.get(operationId);
-            if (pendingTimeout !== undefined) {
+            if (hasProperty(this.pendingTimeouts, operationId)) {
                 // another operation was already scheduled for this id - cancel it
-                this.host.clearTimeout(pendingTimeout);
+                this.host.clearTimeout(this.pendingTimeouts[operationId]);
             }
             // schedule new operation, pass arguments
-            this.pendingTimeouts.set(operationId, this.host.setTimeout(ThrottledOperations.run, delay, this, operationId, cb));
+            this.pendingTimeouts[operationId] = this.host.setTimeout(ThrottledOperations.run, delay, this, operationId, cb);
         }
 
         private static run(self: ThrottledOperations, operationId: string, cb: () => void) {
-            self.pendingTimeouts.delete(operationId);
+            delete self.pendingTimeouts[operationId];
             cb();
         }
     }
diff --git a/src/services/classifier.ts b/src/services/classifier.ts
index 553d184eb9560..c22aec6a78655 100644
--- a/src/services/classifier.ts
+++ b/src/services/classifier.ts
@@ -462,7 +462,7 @@ namespace ts {
     }
 
     /* @internal */
-    export function getSemanticClassifications(typeChecker: TypeChecker, cancellationToken: CancellationToken, sourceFile: SourceFile, classifiableNames: Set<string>, span: TextSpan): ClassifiedSpan[] {
+    export function getSemanticClassifications(typeChecker: TypeChecker, cancellationToken: CancellationToken, sourceFile: SourceFile, classifiableNames: Map<string>, span: TextSpan): ClassifiedSpan[] {
         return convertClassifications(getEncodedSemanticClassifications(typeChecker, cancellationToken, sourceFile, classifiableNames, span));
     }
 
@@ -487,7 +487,7 @@ namespace ts {
     }
 
     /* @internal */
-    export function getEncodedSemanticClassifications(typeChecker: TypeChecker, cancellationToken: CancellationToken, sourceFile: SourceFile, classifiableNames: Set<string>, span: TextSpan): Classifications {
+    export function getEncodedSemanticClassifications(typeChecker: TypeChecker, cancellationToken: CancellationToken, sourceFile: SourceFile, classifiableNames: Map<string>, span: TextSpan): Classifications {
         const result: number[] = [];
         processNode(sourceFile);
 
@@ -557,7 +557,7 @@ namespace ts {
                     // Only bother calling into the typechecker if this is an identifier that
                     // could possibly resolve to a type name.  This makes classification run
                     // in a third of the time it would normally take.
-                    if (classifiableNames.has(identifier.text)) {
+                    if (classifiableNames[identifier.text]) {
                         const symbol = typeChecker.getSymbolAtLocation(node);
                         if (symbol) {
                             const type = classifySymbol(symbol, getMeaningFromLocation(node));
diff --git a/src/services/codefixes/codeFixProvider.ts b/src/services/codefixes/codeFixProvider.ts
index 6b27b11e4369f..c61cbe1b19ea5 100644
--- a/src/services/codefixes/codeFixProvider.ts
+++ b/src/services/codefixes/codeFixProvider.ts
@@ -14,24 +14,25 @@ namespace ts {
     }
 
     export namespace codefix {
-        const codeFixes = createMap<number, CodeFix[]>();
+        const codeFixes = createMap<CodeFix[]>();
 
         export function registerCodeFix(action: CodeFix) {
             forEach(action.errorCodes, error => {
-                multiMapAdd(codeFixes, error, action);
+                let fixes = codeFixes[error];
+                if (!fixes) {
+                    fixes = [];
+                    codeFixes[error] = fixes;
+                }
+                fixes.push(action);
             });
         }
 
         export function getSupportedErrorCodes() {
-            const supportedErrorCodes: string[] = [];
-            codeFixes.forEach((_, key) => {
-                supportedErrorCodes.push(key.toString());
-            });
-            return supportedErrorCodes;
+            return Object.keys(codeFixes);
         }
 
         export function getFixes(context: CodeFixContext): CodeAction[] {
-            const fixes = codeFixes.get(context.errorCode);
+            const fixes = codeFixes[context.errorCode];
             let allActions: CodeAction[] = [];
 
             forEach(fixes, f => {
diff --git a/src/services/completions.ts b/src/services/completions.ts
index 5005343ca9273..b710aa8cd78bb 100644
--- a/src/services/completions.ts
+++ b/src/services/completions.ts
@@ -60,17 +60,18 @@ namespace ts.Completions {
 
         return { isGlobalCompletion, isMemberCompletion, isNewIdentifierLocation: isNewIdentifierLocation, entries };
 
-        function getJavaScriptCompletionEntries(sourceFile: SourceFile, position: number, uniqueNames: Set<string>): CompletionEntry[] {
+        function getJavaScriptCompletionEntries(sourceFile: SourceFile, position: number, uniqueNames: Map<string>): CompletionEntry[] {
             const entries: CompletionEntry[] = [];
 
-            getNameTable(sourceFile).forEach((nameTablePosition, name) => {
+            const nameTable = getNameTable(sourceFile);
+            for (const name in nameTable) {
                 // Skip identifiers produced only from the current location
-                if (nameTablePosition === position) {
-                    return;
+                if (nameTable[name] === position) {
+                    continue;
                 }
 
-                if (!uniqueNames.has(name)) {
-                    uniqueNames.add(name);
+                if (!uniqueNames[name]) {
+                    uniqueNames[name] = name;
                     const displayName = getCompletionEntryDisplayName(unescapeIdentifier(name), compilerOptions.target, /*performCharacterChecks*/ true);
                     if (displayName) {
                         const entry = {
@@ -82,7 +83,7 @@ namespace ts.Completions {
                         entries.push(entry);
                     }
                 }
-            });
+            }
 
             return entries;
         }
@@ -113,17 +114,17 @@ namespace ts.Completions {
 
         }
 
-        function getCompletionEntriesFromSymbols(symbols: Symbol[], entries: CompletionEntry[], location: Node, performCharacterChecks: boolean): Set<string> {
+        function getCompletionEntriesFromSymbols(symbols: Symbol[], entries: CompletionEntry[], location: Node, performCharacterChecks: boolean): Map<string> {
             const start = timestamp();
-            const uniqueNames = createSet();
+            const uniqueNames = createMap<string>();
             if (symbols) {
                 for (const symbol of symbols) {
                     const entry = createCompletionEntry(symbol, location, performCharacterChecks);
                     if (entry) {
                         const id = escapeIdentifier(entry.name);
-                        if (!uniqueNames.has(id)) {
+                        if (!uniqueNames[id]) {
                             entries.push(entry);
-                            uniqueNames.add(id);
+                            uniqueNames[id] = id;
                         }
                     }
                 }
@@ -363,7 +364,7 @@ namespace ts.Completions {
                      *
                      * both foo.ts and foo.tsx become foo
                      */
-                    const foundFiles = createSet();
+                    const foundFiles = createMap<boolean>();
                     for (let filePath of files) {
                         filePath = normalizePath(filePath);
                         if (exclude && comparePaths(filePath, exclude, scriptPath, ignoreCase) === Comparison.EqualTo) {
@@ -372,14 +373,14 @@ namespace ts.Completions {
 
                         const foundFileName = includeExtensions ? getBaseFileName(filePath) : removeFileExtension(getBaseFileName(filePath));
 
-                        if (!foundFiles.has(foundFileName)) {
-                            foundFiles.add(foundFileName);
+                        if (!foundFiles[foundFileName]) {
+                            foundFiles[foundFileName] = true;
                         }
                     }
 
-                    foundFiles.forEach(foundFile => {
+                    for (const foundFile in foundFiles) {
                         result.push(createCompletionEntryForModule(foundFile, ScriptElementKind.scriptElement, span));
-                    });
+                    }
                 }
 
                 // If possible, get folder completion as well
@@ -417,7 +418,7 @@ namespace ts.Completions {
 
                 if (paths) {
                     for (const path in paths) {
-                        if (hasProperty(paths, path)) {
+                        if (paths.hasOwnProperty(path)) {
                             if (path === "*") {
                                 if (paths[path]) {
                                     for (const pattern of paths[path]) {
@@ -1553,7 +1554,7 @@ namespace ts.Completions {
          *          do not occur at the current position and have not otherwise been typed.
          */
         function filterNamedImportOrExportCompletionItems(exportsOfModule: Symbol[], namedImportsOrExports: ImportOrExportSpecifier[]): Symbol[] {
-            const existingImportsOrExports = createSet();
+            const existingImportsOrExports = createMap<boolean>();
 
             for (const element of namedImportsOrExports) {
                 // If this is the current item we are editing right now, do not filter it out
@@ -1562,14 +1563,14 @@ namespace ts.Completions {
                 }
 
                 const name = element.propertyName || element.name;
-                existingImportsOrExports.add(name.text);
+                existingImportsOrExports[name.text] = true;
             }
 
-            if (setIsEmpty(existingImportsOrExports)) {
+            if (!someProperties(existingImportsOrExports)) {
                 return filter(exportsOfModule, e => e.name !== "default");
             }
 
-            return filter(exportsOfModule, e => e.name !== "default" && !existingImportsOrExports.has(e.name));
+            return filter(exportsOfModule, e => e.name !== "default" && !existingImportsOrExports[e.name]);
         }
 
         /**
@@ -1583,7 +1584,7 @@ namespace ts.Completions {
                 return contextualMemberSymbols;
             }
 
-            const existingMemberNames = createSet();
+            const existingMemberNames = createMap<boolean>();
             for (const m of existingMembers) {
                 // Ignore omitted expressions for missing members
                 if (m.kind !== SyntaxKind.PropertyAssignment &&
@@ -1615,10 +1616,10 @@ namespace ts.Completions {
                     existingName = (<Identifier>m.name).text;
                 }
 
-                existingMemberNames.add(existingName);
+                existingMemberNames[existingName] = true;
             }
 
-            return filter(contextualMemberSymbols, m => !existingMemberNames.has(m.name));
+            return filter(contextualMemberSymbols, m => !existingMemberNames[m.name]);
         }
 
         /**
@@ -1628,7 +1629,7 @@ namespace ts.Completions {
          *          do not occur at the current position and have not otherwise been typed.
          */
         function filterJsxAttributes(symbols: Symbol[], attributes: NodeArray<JsxAttribute | JsxSpreadAttribute>): Symbol[] {
-            const seenNames = createSet();
+            const seenNames = createMap<boolean>();
             for (const attr of attributes) {
                 // If this is the current item we are editing right now, do not filter it out
                 if (attr.getStart() <= position && position <= attr.getEnd()) {
@@ -1636,11 +1637,11 @@ namespace ts.Completions {
                 }
 
                 if (attr.kind === SyntaxKind.JsxAttribute) {
-                    seenNames.add((<JsxAttribute>attr).name.text);
+                    seenNames[(<JsxAttribute>attr).name.text] = true;
                 }
             }
 
-            return filter(symbols, a => !seenNames.has(a.name));
+            return filter(symbols, a => !seenNames[a.name]);
         }
     }
 
diff --git a/src/services/documentHighlights.ts b/src/services/documentHighlights.ts
index 791ad48d9d682..0f18427e56885 100644
--- a/src/services/documentHighlights.ts
+++ b/src/services/documentHighlights.ts
@@ -39,16 +39,16 @@ namespace ts.DocumentHighlights {
                     return undefined;
                 }
 
-                const fileNameToDocumentHighlights = createMap<string, DocumentHighlights>();
+                const fileNameToDocumentHighlights = createMap<DocumentHighlights>();
                 const result: DocumentHighlights[] = [];
                 for (const referencedSymbol of referencedSymbols) {
                     for (const referenceEntry of referencedSymbol.references) {
                         const fileName = referenceEntry.fileName;
-                        let documentHighlights = fileNameToDocumentHighlights.get(fileName);
+                        let documentHighlights = fileNameToDocumentHighlights[fileName];
                         if (!documentHighlights) {
                             documentHighlights = { fileName, highlightSpans: [] };
 
-                            fileNameToDocumentHighlights.set(fileName, documentHighlights);
+                            fileNameToDocumentHighlights[fileName] = documentHighlights;
                             result.push(documentHighlights);
                         }
 
diff --git a/src/services/documentRegistry.ts b/src/services/documentRegistry.ts
index 5c5a7797d2d09..d73e4d3b0a125 100644
--- a/src/services/documentRegistry.ts
+++ b/src/services/documentRegistry.ts
@@ -105,7 +105,7 @@ namespace ts {
     export function createDocumentRegistry(useCaseSensitiveFileNames?: boolean, currentDirectory = ""): DocumentRegistry {
         // Maps from compiler setting target (ES3, ES5, etc.) to all the cached documents we have
         // for those settings.
-        const buckets = createMap<string, FileMap<DocumentRegistryEntry>>();
+        const buckets = createMap<FileMap<DocumentRegistryEntry>>();
         const getCanonicalFileName = createGetCanonicalFileName(!!useCaseSensitiveFileNames);
 
         function getKeyForCompilationSettings(settings: CompilerOptions): DocumentRegistryBucketKey {
@@ -113,35 +113,30 @@ namespace ts {
         }
 
         function getBucketForCompilationSettings(key: DocumentRegistryBucketKey, createIfMissing: boolean): FileMap<DocumentRegistryEntry> {
-            let bucket = buckets.get(key);
+            let bucket = buckets[key];
             if (!bucket && createIfMissing) {
-                buckets.set(key, bucket = createFileMap<DocumentRegistryEntry>());
+                buckets[key] = bucket = createFileMap<DocumentRegistryEntry>();
             }
             return bucket;
         }
 
         function reportStats() {
-            type Info = {
-                bucket: string;
-                sourceFiles: { name: string, refCount: number, references: string[] }[]
-            };
-
-            const bucketInfoArray: Info[] = [];
-            buckets.forEach((entries, name) => {
-                if (name && name.charAt(0) === "_") {
-                    const sourceFiles: { name: string; refCount: number; references: string[]; }[] = [];
-                    entries.forEachValue((key, entry) => {
-                        sourceFiles.push({
-                            name: key,
-                            refCount: entry.languageServiceRefCount,
-                            references: entry.owners
-                        });
+            const bucketInfoArray = Object.keys(buckets).filter(name => name && name.charAt(0) === "_").map(name => {
+                const entries = buckets[name];
+                const sourceFiles: { name: string; refCount: number; references: string[]; }[] = [];
+                entries.forEachValue((key, entry) => {
+                    sourceFiles.push({
+                        name: key,
+                        refCount: entry.languageServiceRefCount,
+                        references: entry.owners.slice(0)
                     });
-                    sourceFiles.sort((x, y) => y.refCount - x.refCount);
-                    bucketInfoArray.push({ bucket: name, sourceFiles });
-                }
+                });
+                sourceFiles.sort((x, y) => y.refCount - x.refCount);
+                return {
+                    bucket: name,
+                    sourceFiles
+                };
             });
-
             return JSON.stringify(bucketInfoArray, undefined, 2);
         }
 
diff --git a/src/services/findAllReferences.ts b/src/services/findAllReferences.ts
index fa86aba26aaa4..9765780ee7c8f 100644
--- a/src/services/findAllReferences.ts
+++ b/src/services/findAllReferences.ts
@@ -96,7 +96,7 @@ namespace ts.FindAllReferences {
 
                 const nameTable = getNameTable(sourceFile);
 
-                if (nameTable.get(internedName) !== undefined) {
+                if (nameTable[internedName] !== undefined) {
                     result = result || [];
                     getReferencesInNode(sourceFile, symbol, declaredName, node, searchMeaning, findInStrings, findInComments, result, symbolToIndex);
                 }
@@ -378,7 +378,7 @@ namespace ts.FindAllReferences {
             const possiblePositions = getPossibleSymbolReferencePositions(sourceFile, searchText, start, container.getEnd());
 
             const parents = getParentSymbolsOfPropertyAccess();
-            const inheritsFromCache = createMap<string, boolean>();
+            const inheritsFromCache: Map<boolean> = createMap<boolean>();
 
             if (possiblePositions.length) {
                 // Build the set of symbols to search for, initially it has only the current symbol
@@ -501,14 +501,14 @@ namespace ts.FindAllReferences {
             function findOwnConstructorCalls(classSymbol: Symbol): Node[] {
                 const result: Node[] = [];
 
-                for (const decl of classSymbol.members.get("__constructor").declarations) {
+                for (const decl of classSymbol.members["__constructor"].declarations) {
                     Debug.assert(decl.kind === SyntaxKind.Constructor);
                     const ctrKeyword = decl.getChildAt(0);
                     Debug.assert(ctrKeyword.kind === SyntaxKind.ConstructorKeyword);
                     result.push(ctrKeyword);
                 }
 
-                classSymbol.exports.forEach(member => {
+                forEachProperty(classSymbol.exports, member => {
                     const decl = member.valueDeclaration;
                     if (decl && decl.kind === SyntaxKind.MethodDeclaration) {
                         const body = (<MethodDeclaration>decl).body;
@@ -528,7 +528,7 @@ namespace ts.FindAllReferences {
             /** Find references to `super` in the constructor of an extending class.  */
             function superConstructorAccesses(cls: ClassLikeDeclaration): Node[] {
                 const symbol = cls.symbol;
-                const ctr = symbol.members.get("__constructor");
+                const ctr = symbol.members["__constructor"];
                 if (!ctr) {
                     return [];
                 }
@@ -705,7 +705,7 @@ namespace ts.FindAllReferences {
          * @param parent        Another class or interface Symbol
          * @param cachedResults A map of symbol id pairs (i.e. "child,parent") to booleans indicating previous results
          */
-        function explicitlyInheritsFrom(child: Symbol, parent: Symbol, cachedResults: Map<string, boolean>): boolean {
+        function explicitlyInheritsFrom(child: Symbol, parent: Symbol, cachedResults: Map<boolean>): boolean {
             const parentIsInterface = parent.getFlags() & SymbolFlags.Interface;
             return searchHierarchy(child);
 
@@ -715,13 +715,12 @@ namespace ts.FindAllReferences {
                 }
 
                 const key = getSymbolId(symbol) + "," + getSymbolId(parent);
-                const cachedResult = cachedResults.get(key);
-                if (cachedResult !== undefined) {
-                    return cachedResult;
+                if (key in cachedResults) {
+                    return cachedResults[key];
                 }
 
                 // Set the key so that we don't infinitely recurse
-                cachedResults.set(key, false);
+                cachedResults[key] = false;
 
                 const inherits = forEach(symbol.getDeclarations(), declaration => {
                     if (isClassLike(declaration)) {
@@ -745,7 +744,7 @@ namespace ts.FindAllReferences {
                     return false;
                 });
 
-                cachedResults.set(key, inherits);
+                cachedResults[key] = inherits;
                 return inherits;
             }
 
@@ -1047,7 +1046,7 @@ namespace ts.FindAllReferences {
 
                 // Add symbol of properties/methods of the same name in base classes and implemented interfaces definitions
                 if (!implementations && rootSymbol.parent && rootSymbol.parent.flags & (SymbolFlags.Class | SymbolFlags.Interface)) {
-                    getPropertySymbolsFromBaseTypes(rootSymbol.parent, rootSymbol.getName(), result, /*previousIterationSymbolsCache*/ createMap<string, Symbol>());
+                    getPropertySymbolsFromBaseTypes(rootSymbol.parent, rootSymbol.getName(), result, /*previousIterationSymbolsCache*/ createMap<Symbol>());
                 }
             });
 
@@ -1079,7 +1078,7 @@ namespace ts.FindAllReferences {
             // the function will add any found symbol of the property-name, then its sub-routine will call
             // getPropertySymbolsFromBaseTypes again to walk up any base types to prevent revisiting already
             // visited symbol, interface "C", the sub-routine will pass the current symbol as previousIterationSymbol.
-            if (previousIterationSymbolsCache.has(symbol.name)) {
+            if (symbol.name in previousIterationSymbolsCache) {
                 return;
             }
 
@@ -1106,14 +1105,14 @@ namespace ts.FindAllReferences {
                         }
 
                         // Visit the typeReference as well to see if it directly or indirectly use that property
-                        previousIterationSymbolsCache.set(symbol.name, symbol);
+                        previousIterationSymbolsCache[symbol.name] = symbol;
                         getPropertySymbolsFromBaseTypes(type.symbol, propertyName, result, previousIterationSymbolsCache);
                     }
                 }
             }
         }
 
-        function getRelatedSymbol(searchSymbols: Symbol[], referenceSymbol: Symbol, referenceLocation: Node, searchLocationIsConstructor: boolean, parents: Symbol[] | undefined, cache: Map<string, boolean>): Symbol {
+        function getRelatedSymbol(searchSymbols: Symbol[], referenceSymbol: Symbol, referenceLocation: Node, searchLocationIsConstructor: boolean, parents: Symbol[] | undefined, cache: Map<boolean>): Symbol {
             if (contains(searchSymbols, referenceSymbol)) {
                 // If we are searching for constructor uses, they must be 'new' expressions.
                 return (!searchLocationIsConstructor || isNewExpressionTarget(referenceLocation)) && referenceSymbol;
@@ -1177,7 +1176,7 @@ namespace ts.FindAllReferences {
                     }
 
                     const result: Symbol[] = [];
-                    getPropertySymbolsFromBaseTypes(rootSymbol.parent, rootSymbol.getName(), result, /*previousIterationSymbolsCache*/ createMap<string, Symbol>());
+                    getPropertySymbolsFromBaseTypes(rootSymbol.parent, rootSymbol.getName(), result, /*previousIterationSymbolsCache*/ createMap<Symbol>());
                     return forEach(result, s => searchSymbols.indexOf(s) >= 0 ? s : undefined);
                 }
 
diff --git a/src/services/formatting/rules.ts b/src/services/formatting/rules.ts
index 215289159c289..2095f062bd103 100644
--- a/src/services/formatting/rules.ts
+++ b/src/services/formatting/rules.ts
@@ -4,7 +4,7 @@
 namespace ts.formatting {
     export class Rules {
         public getRuleName(rule: Rule) {
-            const o: ts.MapLike<any> = <any>this;
+            const o: ts.Map<any> = <any>this;
             for (const name in o) {
                 if (o[name] === rule) {
                     return name;
diff --git a/src/services/goToDefinition.ts b/src/services/goToDefinition.ts
index d6ade7aed6bd9..4c005640d6ae8 100644
--- a/src/services/goToDefinition.ts
+++ b/src/services/goToDefinition.ts
@@ -14,7 +14,7 @@ namespace ts.GoToDefinition {
         // Type reference directives
         const typeReferenceDirective = findReferenceInPosition(sourceFile.typeReferenceDirectives, position);
         if (typeReferenceDirective) {
-            const referenceFile = program.getResolvedTypeReferenceDirectives().get(typeReferenceDirective.fileName);
+            const referenceFile = program.getResolvedTypeReferenceDirectives()[typeReferenceDirective.fileName];
             if (referenceFile && referenceFile.resolvedFileName) {
                 return [getDefinitionInfoForFileReference(typeReferenceDirective.fileName, referenceFile.resolvedFileName)];
             }
diff --git a/src/services/jsTyping.ts b/src/services/jsTyping.ts
index a4841a17752b0..0f635c151740a 100644
--- a/src/services/jsTyping.ts
+++ b/src/services/jsTyping.ts
@@ -17,19 +17,19 @@ namespace ts.JsTyping {
 
     interface PackageJson {
         _requiredBy?: string[];
-        dependencies?: MapLike<string>;
-        devDependencies?: MapLike<string>;
+        dependencies?: Map<string>;
+        devDependencies?: Map<string>;
         name?: string;
-        optionalDependencies?: MapLike<string>;
-        peerDependencies?: MapLike<string>;
+        optionalDependencies?: Map<string>;
+        peerDependencies?: Map<string>;
         typings?: string;
     };
 
     // A map of loose file names to library names
     // that we are confident require typings
-    let safeList: Map<string, string>;
+    let safeList: Map<string>;
 
-    const EmptySafeList = createMap<string, string>();
+    const EmptySafeList: Map<string> = createMap<string>();
 
     /* @internal */
     export const nodeCoreModuleList: ReadonlyArray<string> = [
@@ -56,13 +56,13 @@ namespace ts.JsTyping {
         fileNames: string[],
         projectRootPath: Path,
         safeListPath: Path,
-        packageNameToTypingLocation: Map<string, string>,
+        packageNameToTypingLocation: Map<string>,
         typingOptions: TypingOptions,
         unresolvedImports: ReadonlyArray<string>):
         { cachedTypingPaths: string[], newTypingNames: string[], filesToWatch: string[] } {
 
         // A typing name to typing file path mapping
-        const inferredTypings = createMap<string, string | undefined>();
+        const inferredTypings = createMap<string>();
 
         if (!typingOptions || !typingOptions.enableAutoDiscovery) {
             return { cachedTypingPaths: [], newTypingNames: [], filesToWatch: [] };
@@ -76,7 +76,7 @@ namespace ts.JsTyping {
 
         if (!safeList) {
             const result = readConfigFile(safeListPath, (path: string) => host.readFile(path));
-            safeList = result.config ? mapOfMapLike<string>(result.config) : EmptySafeList;
+            safeList = result.config ? createMap<string>(result.config) : EmptySafeList;
         }
 
         const filesToWatch: string[] = [];
@@ -107,35 +107,34 @@ namespace ts.JsTyping {
         // add typings for unresolved imports
         if (unresolvedImports) {
             for (const moduleId of unresolvedImports) {
-                const typingName = nodeCoreModules.has(moduleId) ? "node" : moduleId;
-                if (!inferredTypings.has(typingName)) {
-                    inferredTypings.set(typingName, undefined);
+                const typingName = moduleId in nodeCoreModules ? "node" : moduleId;
+                if (!(typingName in inferredTypings)) {
+                    inferredTypings[typingName] = undefined;
                 }
             }
         }
         // Add the cached typing locations for inferred typings that are already installed
-        packageNameToTypingLocation.forEach((typingLocation, name) => {
-            if (inferredTypings.has(name) && inferredTypings.get(name) === undefined) {
-                inferredTypings.set(name, typingLocation);
+        for (const name in packageNameToTypingLocation) {
+            if (name in inferredTypings && !inferredTypings[name]) {
+                inferredTypings[name] = packageNameToTypingLocation[name];
             }
-        });
+        }
 
         // Remove typings that the user has added to the exclude list
         for (const excludeTypingName of exclude) {
-            inferredTypings.delete(excludeTypingName);
+            delete inferredTypings[excludeTypingName];
         }
 
         const newTypingNames: string[] = [];
         const cachedTypingPaths: string[] = [];
-
-        inferredTypings.forEach((inferredTyping, typing) => {
-            if (inferredTyping !== undefined) {
-                cachedTypingPaths.push(inferredTyping);
+        for (const typing in inferredTypings) {
+            if (inferredTypings[typing] !== undefined) {
+                cachedTypingPaths.push(inferredTypings[typing]);
             }
             else {
                 newTypingNames.push(typing);
             }
-        });
+        }
         return { cachedTypingPaths, newTypingNames, filesToWatch };
 
         /**
@@ -147,8 +146,8 @@ namespace ts.JsTyping {
             }
 
             for (const typing of typingNames) {
-                if (!inferredTypings.has(typing)) {
-                    inferredTypings.set(typing, undefined);
+                if (!(typing in inferredTypings)) {
+                    inferredTypings[typing] = undefined;
                 }
             }
         }
@@ -190,7 +189,7 @@ namespace ts.JsTyping {
             const cleanedTypingNames = map(inferredTypingNames, f => f.replace(/((?:\.|-)min(?=\.|$))|((?:-|\.)\d+)/g, ""));
 
             if (safeList !== EmptySafeList) {
-                mergeTypings(filter(cleanedTypingNames, f => safeList.has(f)));
+                mergeTypings(filter(cleanedTypingNames, f => f in safeList));
             }
 
             const hasJsxFile = forEach(fileNames, f => ensureScriptKind(f, getScriptKindFromFileName(f)) === ScriptKind.JSX);
@@ -237,7 +236,7 @@ namespace ts.JsTyping {
                 }
                 if (packageJson.typings) {
                     const absolutePath = getNormalizedAbsolutePath(packageJson.typings, getDirectoryPath(normalizedFileName));
-                    inferredTypings.set(packageJson.name, absolutePath);
+                    inferredTypings[packageJson.name] = absolutePath;
                 }
                 else {
                     typingNames.push(packageJson.name);
diff --git a/src/services/navigateTo.ts b/src/services/navigateTo.ts
index dbe32d84baf18..82f4dd49f2b73 100644
--- a/src/services/navigateTo.ts
+++ b/src/services/navigateTo.ts
@@ -7,22 +7,23 @@ namespace ts.NavigateTo {
         let rawItems: RawNavigateToItem[] = [];
 
         // Search the declarations in all files and output matched NavigateToItem into array of NavigateToItem[]
-        for (const sourceFile of sourceFiles) {
+        forEach(sourceFiles, sourceFile => {
             cancellationToken.throwIfCancellationRequested();
 
             if (excludeDtsFiles && fileExtensionIs(sourceFile.fileName, ".d.ts")) {
-                continue;
+                return;
             }
 
-            // Use `someInMap` to break out early.
-            someInMap(sourceFile.getNamedDeclarations(), (declarations, name) => {
+            const nameToDeclarations = sourceFile.getNamedDeclarations();
+            for (const name in nameToDeclarations) {
+                const declarations = nameToDeclarations[name];
                 if (declarations) {
                     // First do a quick check to see if the name of the declaration matches the
                     // last portion of the (possibly) dotted name they're searching for.
                     let matches = patternMatcher.getMatchesForLastSegmentOfPattern(name);
 
                     if (!matches) {
-                        return false;
+                        continue;
                     }
 
                     for (const declaration of declarations) {
@@ -31,13 +32,13 @@ namespace ts.NavigateTo {
                         if (patternMatcher.patternContainsDots) {
                             const containers = getContainers(declaration);
                             if (!containers) {
-                                return true; // Go to the next source file.
+                                return undefined;
                             }
 
                             matches = patternMatcher.getMatches(containers, name);
 
                             if (!matches) {
-                                return false;
+                                continue;
                             }
                         }
 
@@ -46,8 +47,8 @@ namespace ts.NavigateTo {
                         rawItems.push({ name, fileName, matchKind, isCaseSensitive: allMatchesAreCaseSensitive(matches), declaration });
                     }
                 }
-            });
-        }
+            }
+        });
 
         // Remove imports when the imported declaration is already in the list and has the same name.
         rawItems = filter(rawItems, item => {
diff --git a/src/services/navigationBar.ts b/src/services/navigationBar.ts
index 00472f46c74bb..51ce9b6001d53 100644
--- a/src/services/navigationBar.ts
+++ b/src/services/navigationBar.ts
@@ -239,7 +239,7 @@ namespace ts.NavigationBar {
 
     /** Merge declarations of the same kind. */
     function mergeChildren(children: NavigationBarNode[]): void {
-        const nameToItems = createMap<string, NavigationBarNode | NavigationBarNode[]>();
+        const nameToItems = createMap<NavigationBarNode | NavigationBarNode[]>();
         filterMutate(children, child => {
             const decl = <Declaration>child.node;
             const name = decl.name && nodeText(decl.name);
@@ -248,9 +248,9 @@ namespace ts.NavigationBar {
                 return true;
             }
 
-            const itemsWithSameName = nameToItems.get(name);
+            const itemsWithSameName = nameToItems[name];
             if (!itemsWithSameName) {
-                nameToItems.set(name, child);
+                nameToItems[name] = child;
                 return true;
             }
 
@@ -268,7 +268,7 @@ namespace ts.NavigationBar {
                 if (tryMerge(itemWithSameName, child)) {
                     return false;
                 }
-                nameToItems.set(name, [itemWithSameName, child]);
+                nameToItems[name] = [itemWithSameName, child];
                 return true;
             }
 
@@ -626,15 +626,15 @@ namespace ts.NavigationBar {
 
     /**
      * Matches all whitespace characters in a string. Eg:
-     *
+     * 
      * "app.
-     *
+     * 
      * onactivated"
-     *
+     * 
      * matches because of the newline, whereas
-     *
+     * 
      * "app.onactivated"
-     *
+     * 
      * does not match.
      */
     const whiteSpaceRegex = /\s+/g;
diff --git a/src/services/patternMatcher.ts b/src/services/patternMatcher.ts
index cf107d8984bf3..b4f67ca056ddb 100644
--- a/src/services/patternMatcher.ts
+++ b/src/services/patternMatcher.ts
@@ -113,7 +113,7 @@ namespace ts {
         // we see the name of a module that is used everywhere, or the name of an overload).  As
         // such, we cache the information we compute about the candidate for the life of this
         // pattern matcher so we don't have to compute it multiple times.
-        const stringToWordSpans = createMap<string, TextSpan[]>();
+        const stringToWordSpans = createMap<TextSpan[]>();
 
         pattern = pattern.trim();
 
@@ -188,7 +188,11 @@ namespace ts {
         }
 
         function getWordSpans(word: string): TextSpan[] {
-            return getOrUpdate(stringToWordSpans, word, breakIntoWordSpans);
+            if (!(word in stringToWordSpans)) {
+                stringToWordSpans[word] = breakIntoWordSpans(word);
+            }
+
+            return stringToWordSpans[word];
         }
 
         function matchTextChunk(candidate: string, chunk: TextChunk, punctuationStripped: boolean): PatternMatch {
diff --git a/src/services/services.ts b/src/services/services.ts
index ac77391cc1211..8c11c707e5d60 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -465,13 +465,13 @@ namespace ts {
         public scriptKind: ScriptKind;
         public languageVersion: ScriptTarget;
         public languageVariant: LanguageVariant;
-        public identifiers: Map<string, string>;
-        public nameTable: Map<string, number>;
-        public resolvedModules: Map<string, ResolvedModuleFull>;
-        public resolvedTypeReferenceDirectiveNames: Map<string, ResolvedTypeReferenceDirective>;
+        public identifiers: Map<string>;
+        public nameTable: Map<number>;
+        public resolvedModules: Map<ResolvedModuleFull>;
+        public resolvedTypeReferenceDirectiveNames: Map<ResolvedTypeReferenceDirective>;
         public imports: LiteralExpression[];
         public moduleAugmentations: LiteralExpression[];
-        private namedDeclarations: Map<string, Declaration[]>;
+        private namedDeclarations: Map<Declaration[]>;
 
         constructor(kind: SyntaxKind, pos: number, end: number) {
             super(kind, pos, end);
@@ -493,7 +493,7 @@ namespace ts {
             return ts.getPositionOfLineAndCharacter(this, line, character);
         }
 
-        public getNamedDeclarations(): Map<string, Declaration[]> {
+        public getNamedDeclarations(): Map<Declaration[]> {
             if (!this.namedDeclarations) {
                 this.namedDeclarations = this.computeNamedDeclarations();
             }
@@ -501,8 +501,8 @@ namespace ts {
             return this.namedDeclarations;
         }
 
-        private computeNamedDeclarations(): Map<string, Declaration[]> {
-            const result = createMap<string, Declaration[]>();
+        private computeNamedDeclarations(): Map<Declaration[]> {
+            const result = createMap<Declaration[]>();
 
             forEachChild(this, visit);
 
@@ -516,7 +516,7 @@ namespace ts {
             }
 
             function getDeclarations(name: string) {
-                return getOrUpdate(result, name, () => []);
+                return result[name] || (result[name] = []);
             }
 
             function getDeclarationName(declaration: Declaration) {
@@ -967,7 +967,7 @@ namespace ts {
         const currentDirectory = host.getCurrentDirectory();
         // Check if the localized messages json is set, otherwise query the host for it
         if (!localizedDiagnosticMessages && host.getLocalizedDiagnosticMessages) {
-            localizedDiagnosticMessages = mapOfMapLike<string>(host.getLocalizedDiagnosticMessages());
+            localizedDiagnosticMessages = host.getLocalizedDiagnosticMessages();
         }
 
         function log(message: string) {
@@ -1922,7 +1922,7 @@ namespace ts {
     }
 
     /* @internal */
-    export function getNameTable(sourceFile: SourceFile): Map<string, number> {
+    export function getNameTable(sourceFile: SourceFile): Map<number> {
         if (!sourceFile.nameTable) {
             initializeNameTable(sourceFile);
         }
@@ -1931,7 +1931,7 @@ namespace ts {
     }
 
     function initializeNameTable(sourceFile: SourceFile): void {
-        const nameTable = createMap<string, number>();
+        const nameTable = createMap<number>();
 
         walk(sourceFile);
         sourceFile.nameTable = nameTable;
@@ -1939,7 +1939,7 @@ namespace ts {
         function walk(node: Node) {
             switch (node.kind) {
                 case SyntaxKind.Identifier:
-                    nameTable.set((<Identifier>node).text, nameTable.get((<Identifier>node).text) === undefined ? node.pos : -1);
+                    nameTable[(<Identifier>node).text] = nameTable[(<Identifier>node).text] === undefined ? node.pos : -1;
                     break;
                 case SyntaxKind.StringLiteral:
                 case SyntaxKind.NumericLiteral:
@@ -1952,7 +1952,7 @@ namespace ts {
                         isArgumentOfElementAccessExpression(node) ||
                         isLiteralComputedPropertyDeclarationName(node)) {
 
-                        nameTable.set((<LiteralExpression>node).text, nameTable.get((<LiteralExpression>node).text) === undefined ? node.pos : -1);
+                        nameTable[(<LiteralExpression>node).text] = nameTable[(<LiteralExpression>node).text] === undefined ? node.pos : -1;
                     }
                     break;
                 default:
diff --git a/src/services/shims.ts b/src/services/shims.ts
index 8e9155d3eede2..b1fac14674c32 100644
--- a/src/services/shims.ts
+++ b/src/services/shims.ts
@@ -1167,7 +1167,7 @@ namespace ts {
                     info.fileNames,
                     toPath(info.projectRootPath, info.projectRootPath, getCanonicalFileName),
                     toPath(info.safeListPath, info.safeListPath, getCanonicalFileName),
-                    mapOfMapLike(info.packageNameToTypingLocation),
+                    info.packageNameToTypingLocation,
                     info.typingOptions,
                     info.unresolvedImports);
             });
diff --git a/src/services/signatureHelp.ts b/src/services/signatureHelp.ts
index 3562169ac7af6..211e55b23ba5e 100644
--- a/src/services/signatureHelp.ts
+++ b/src/services/signatureHelp.ts
@@ -237,7 +237,7 @@ namespace ts.SignatureHelp {
         const typeChecker = program.getTypeChecker();
         for (const sourceFile of program.getSourceFiles()) {
             const nameToDeclarations = sourceFile.getNamedDeclarations();
-            const declarations = nameToDeclarations.get(name.text);
+            const declarations = nameToDeclarations[name.text];
 
             if (declarations) {
                 for (const declaration of declarations) {
diff --git a/src/services/transpile.ts b/src/services/transpile.ts
index c327186613fb6..da54faed1a2f7 100644
--- a/src/services/transpile.ts
+++ b/src/services/transpile.ts
@@ -63,7 +63,7 @@ namespace ts {
         }
 
         if (transpileOptions.renamedDependencies) {
-            sourceFile.renamedDependencies = mapOfMapLike(transpileOptions.renamedDependencies);
+            sourceFile.renamedDependencies = createMap(transpileOptions.renamedDependencies);
         }
 
         const newLine = getNewLineCharacter(options);
@@ -126,7 +126,7 @@ namespace ts {
     function fixupCompilerOptions(options: CompilerOptions, diagnostics: Diagnostic[]): CompilerOptions {
         // Lazily create this value to fix module loading errors.
         commandLineOptionsStringToEnum = commandLineOptionsStringToEnum || <CommandLineOptionOfCustomType[]>filter(optionDeclarations, o =>
-            typeof o.type === "object" && !someValueInMap(o.type, v => typeof v !== "number"));
+            typeof o.type === "object" && !forEachProperty(o.type, v => typeof v !== "number"));
 
         options = clone(options);
 
@@ -142,7 +142,7 @@ namespace ts {
                 options[opt.name] = parseCustomTypeOption(opt, value, diagnostics);
             }
             else {
-                if (!someValueInMap(opt.type, v => v === value)) {
+                if (!forEachProperty(opt.type, v => v === value)) {
                     // Supplied value isn't a valid enum value.
                     diagnostics.push(createCompilerDiagnosticForInvalidCustomType(opt));
                 }
diff --git a/src/services/types.ts b/src/services/types.ts
index 9989aebaec6c8..4e04df3fc7caf 100644
--- a/src/services/types.ts
+++ b/src/services/types.ts
@@ -48,9 +48,9 @@ namespace ts {
     export interface SourceFile {
         /* @internal */ version: string;
         /* @internal */ scriptSnapshot: IScriptSnapshot;
-        /* @internal */ nameTable: Map<string, number>;
+        /* @internal */ nameTable: Map<number>;
 
-        /* @internal */ getNamedDeclarations(): Map<string, Declaration[]>;
+        /* @internal */ getNamedDeclarations(): Map<Declaration[]>;
 
         getLineAndCharacterOfPosition(pos: number): LineAndCharacter;
         getLineStarts(): number[];
diff --git a/tslint.json b/tslint.json
index d33b87381c859..81990190ddbda 100644
--- a/tslint.json
+++ b/tslint.json
@@ -47,7 +47,6 @@
         "prefer-const": true,
         "no-increment-decrement": true,
         "object-literal-surrounding-space": true,
-        "no-type-assertion-whitespace": true,
-        "no-in-operator": true
+        "no-type-assertion-whitespace": true
   }
 }

From 39b9163715fac6975c5691ae4d85afbc2eabcb62 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 27 Oct 2016 16:03:01 -0700
Subject: [PATCH 110/224] Rename Experimental transform to ESNext

1. Spread/rest are no longer experimental.
2. We need a place to put stage 3 ES features.
---
 Jakefile.js                                              | 4 ++--
 src/compiler/transformer.ts                              | 4 ++--
 src/compiler/transformers/{experimental.ts => esnext.ts} | 2 +-
 src/compiler/tsconfig.json                               | 2 +-
 src/harness/tsconfig.json                                | 2 +-
 src/services/tsconfig.json                               | 2 +-
 6 files changed, 8 insertions(+), 8 deletions(-)
 rename src/compiler/transformers/{experimental.ts => esnext.ts} (95%)

diff --git a/Jakefile.js b/Jakefile.js
index e6698474a22c3..85f5ef681e84d 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -71,7 +71,7 @@ var compilerSources = [
     "transformers/destructuring.ts",
     "transformers/ts.ts",
     "transformers/jsx.ts",
-    "transformers/experimental.ts",
+    "transformers/esnext.ts",
     "transformers/es2017.ts",
     "transformers/es2016.ts",
     "transformers/es2015.ts",
@@ -108,7 +108,7 @@ var servicesSources = [
     "transformers/destructuring.ts",
     "transformers/ts.ts",
     "transformers/jsx.ts",
-    "transformers/experimental.ts",
+    "transformers/esnext.ts",
     "transformers/es2017.ts",
     "transformers/es2016.ts",
     "transformers/es2015.ts",
diff --git a/src/compiler/transformer.ts b/src/compiler/transformer.ts
index 467d57a0983fe..069b1e46af56b 100644
--- a/src/compiler/transformer.ts
+++ b/src/compiler/transformer.ts
@@ -1,7 +1,7 @@
 /// <reference path="visitor.ts" />
 /// <reference path="transformers/ts.ts" />
 /// <reference path="transformers/jsx.ts" />
-/// <reference path="transformers/experimental.ts" />
+/// <reference path="transformers/esnext.ts" />
 /// <reference path="transformers/es2017.ts" />
 /// <reference path="transformers/es2016.ts" />
 /// <reference path="transformers/es2015.ts" />
@@ -117,7 +117,7 @@ namespace ts {
             transformers.push(transformJsx);
         }
 
-        transformers.push(transformExperimental);
+        transformers.push(transformESNext);
         if (languageVersion < ScriptTarget.ES2017) {
             transformers.push(transformES2017);
         }
diff --git a/src/compiler/transformers/experimental.ts b/src/compiler/transformers/esnext.ts
similarity index 95%
rename from src/compiler/transformers/experimental.ts
rename to src/compiler/transformers/esnext.ts
index 2ee623db43aed..58cf1a1c01aeb 100644
--- a/src/compiler/transformers/experimental.ts
+++ b/src/compiler/transformers/esnext.ts
@@ -3,7 +3,7 @@
 
 /*@internal*/
 namespace ts {
-    export function transformExperimental(context: TransformationContext) {
+    export function transformESNext(context: TransformationContext) {
         return transformSourceFile;
 
         function transformSourceFile(node: SourceFile) {
diff --git a/src/compiler/tsconfig.json b/src/compiler/tsconfig.json
index 3e9b6a765bdeb..bd70a0afb10ed 100644
--- a/src/compiler/tsconfig.json
+++ b/src/compiler/tsconfig.json
@@ -27,7 +27,7 @@
         "visitor.ts",
         "transformers/ts.ts",
         "transformers/jsx.ts",
-        "transformers/experimental.ts",
+        "transformers/esnext.ts",
         "transformers/es2017.ts",
         "transformers/es2016.ts",
         "transformers/es2015.ts",
diff --git a/src/harness/tsconfig.json b/src/harness/tsconfig.json
index 9b174236cbcdc..d3a814f26caf0 100644
--- a/src/harness/tsconfig.json
+++ b/src/harness/tsconfig.json
@@ -29,7 +29,7 @@
         "../compiler/visitor.ts",
         "../compiler/transformers/ts.ts",
         "../compiler/transformers/jsx.ts",
-        "../compiler/transformers/experimental.ts",
+        "../compiler/transformers/esnext.ts",
         "../compiler/transformers/es2017.ts",
         "../compiler/transformers/es2016.ts",
         "../compiler/transformers/es2015.ts",
diff --git a/src/services/tsconfig.json b/src/services/tsconfig.json
index 2b947d60cf247..9c3e068918d5e 100644
--- a/src/services/tsconfig.json
+++ b/src/services/tsconfig.json
@@ -28,7 +28,7 @@
         "../compiler/visitor.ts",
         "../compiler/transformers/ts.ts",
         "../compiler/transformers/jsx.ts",
-        "../compiler/transformers/experimental.ts",
+        "../compiler/transformers/esnext.ts",
         "../compiler/transformers/es2017.ts",
         "../compiler/transformers/es2016.ts",
         "../compiler/transformers/es2015.ts",

From 43bd2d8747e92aea869d55685365dd7ead53a065 Mon Sep 17 00:00:00 2001
From: Jason Ramsay <jasonra@microsoft.com>
Date: Thu, 27 Oct 2016 16:38:59 -0700
Subject: [PATCH 111/224] Changes from CR feedback

---
 src/compiler/program.ts | 10 ++++++----
 src/compiler/types.ts   |  4 ++--
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 6c06664d5898d..b7830653c861d 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -727,9 +727,11 @@ namespace ts {
         function getSyntacticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
             // For JavaScript files, we report semantic errors for using TypeScript-only
             // constructs from within a JavaScript file as syntactic errors.
-            if (isSourceFileJavaScript(sourceFile) && !sourceFile.parseJavaScriptDiagnostics) {
-                sourceFile.parseJavaScriptDiagnostics = getJavaScriptSemanticDiagnosticsForFile(sourceFile);
-                sourceFile.parseDiagnostics = sourceFile.parseDiagnostics.concat(sourceFile.parseJavaScriptDiagnostics);
+            if (isSourceFileJavaScript(sourceFile)) {
+                if (!sourceFile.additionalSyntacticDiagnostics) {
+                    sourceFile.additionalSyntacticDiagnostics = getJavaScriptSyntacticDiagnosticsForFile(sourceFile);
+                }
+                return concatenate(sourceFile.additionalSyntacticDiagnostics, sourceFile.parseDiagnostics);
             }
             return sourceFile.parseDiagnostics;
         }
@@ -774,7 +776,7 @@ namespace ts {
             });
         }
 
-        function getJavaScriptSemanticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
+        function getJavaScriptSyntacticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
             return runWithCancellationToken(() => {
                 const diagnostics: Diagnostic[] = [];
                 walk(sourceFile);
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index bda350347c27c..ff0ba2fde867b 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2024,8 +2024,8 @@ namespace ts {
         // as well as code diagnostics).
         /* @internal */ parseDiagnostics: Diagnostic[];
 
-        // Stores file level JavaScript diagnostics reported by the program
-        /* @internal */ parseJavaScriptDiagnostics?: Diagnostic[];
+        // Stores additional file level diagnostics reported by the program
+        /* @internal */ additionalSyntacticDiagnostics?: Diagnostic[];
 
         // File level diagnostics reported by the binder.
         /* @internal */ bindDiagnostics: Diagnostic[];

From 4513ae3034a21c728d610a74c39ab833646024e9 Mon Sep 17 00:00:00 2001
From: Zhengbo Li <zhengbli@microsoft.com>
Date: Thu, 27 Oct 2016 18:00:21 -0700
Subject: [PATCH 112/224] disable CoS for inferred projects (#11909)

---
 src/server/editorServices.ts | 2 +-
 src/server/project.ts        | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index 6565940c22d08..f80305efafa52 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -1008,7 +1008,7 @@ namespace ts.server {
             const useExistingProject = this.useSingleInferredProject && this.inferredProjects.length;
             const project = useExistingProject
                 ? this.inferredProjects[0]
-                : new InferredProject(this, this.documentRegistry, /*languageServiceEnabled*/ true, this.compilerOptionsForInferredProjects, /*compileOnSaveEnabled*/ this.compileOnSaveForInferredProjects);
+                : new InferredProject(this, this.documentRegistry, /*languageServiceEnabled*/ true, this.compilerOptionsForInferredProjects);
 
             project.addRoot(root);
 
diff --git a/src/server/project.ts b/src/server/project.ts
index 5f4f8d4049027..457f5e2b261df 100644
--- a/src/server/project.ts
+++ b/src/server/project.ts
@@ -666,14 +666,14 @@ namespace ts.server {
         // Used to keep track of what directories are watched for this project
         directoriesWatchedForTsconfig: string[] = [];
 
-        constructor(projectService: ProjectService, documentRegistry: ts.DocumentRegistry, languageServiceEnabled: boolean, compilerOptions: CompilerOptions, public compileOnSaveEnabled: boolean) {
+        constructor(projectService: ProjectService, documentRegistry: ts.DocumentRegistry, languageServiceEnabled: boolean, compilerOptions: CompilerOptions) {
             super(ProjectKind.Inferred,
                 projectService,
                 documentRegistry,
                 /*files*/ undefined,
                 languageServiceEnabled,
                 compilerOptions,
-                compileOnSaveEnabled);
+                /*compileOnSaveEnabled*/ false);
 
             this.inferredProjectName = makeInferredProjectName(InferredProject.NextId);
             InferredProject.NextId++;

From 05c2c9b67bdbdda06ca11d9b5c81604a6209caf8 Mon Sep 17 00:00:00 2001
From: Jason Ramsay <jasonra@microsoft.com>
Date: Thu, 27 Oct 2016 19:20:14 -0700
Subject: [PATCH 113/224] Updating test due to CR changes.  The order of the
 diagnostic messages has changed due to concatenation changes

---
 .../server/getJavaScriptSyntacticDiagnostics02.ts  | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts b/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts
index 3439162e6916a..dd9becad10b70 100644
--- a/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts
+++ b/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts
@@ -8,6 +8,13 @@
 //// var var = "c";
 
 verify.getSyntacticDiagnostics(`[
+  {
+    "message": "\'types\' can only be used in a .ts file.",
+    "start": 20,
+    "length": 7,
+    "category": "error",
+    "code": 8010
+  },
   {
     "message": "Variable declaration expected.",
     "start": 67,
@@ -28,13 +35,6 @@ verify.getSyntacticDiagnostics(`[
     "length": 3,
     "category": "error",
     "code": 1134
-  },
-  {
-    "message": "\'types\' can only be used in a .ts file.",
-    "start": 20,
-    "length": 7,
-    "category": "error",
-    "code": 8010
   }
 ]`);
 verify.getSemanticDiagnostics(`[]`);
\ No newline at end of file

From 278d0a4665a5ac9a2a821f890fcb42a6e12202bf Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 27 Oct 2016 22:52:01 -0700
Subject: [PATCH 114/224] Do not use contextual signatures with too few
 parameters

---
 src/compiler/checker.ts                       | 40 +++++++++++--------
 .../contextualTypingOfTooShortOverloads.types |  6 +--
 ...WithOverloadedFunctionTypedArguments.types |  4 +-
 ...AnnotatedFunctionInferenceError.errors.txt | 12 +++---
 4 files changed, 35 insertions(+), 27 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 812c55d0ea252..b188fec8b4d26 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -10343,6 +10343,10 @@ namespace ts {
             if (!type) {
                 return undefined;
             }
+            // If the contextual signature has fewer parameters than the function expression, do not use it
+            if (isFunctionExpressionOrArrowFunction(node) && isAritySmaller(type, node)) {
+                return undefined;
+            }
             if (!(type.flags & TypeFlags.Union)) {
                 return getNonGenericSignature(type);
             }
@@ -10377,6 +10381,26 @@ namespace ts {
             return result;
         }
 
+        function isAritySmaller(sourceType: Type, target: FunctionExpression | ArrowFunction) {
+            if (isFunctionType(sourceType)) {
+                let targetParameterCount = 0;
+                for (; targetParameterCount < target.parameters.length; targetParameterCount++) {
+                    const param = target.parameters[targetParameterCount];
+                    if (param.initializer || param.questionToken || param.dotDotDotToken || isJSDocOptionalParameter(param)) {
+                        break;
+                    }
+                }
+                if (target.parameters.length && parameterIsThisKeyword(target.parameters[0])) {
+                    targetParameterCount--;
+                }
+                const sourceSignatures = getSignaturesOfType(sourceType, SignatureKind.Call);
+                const sourceLengths = sourceSignatures.map(sig => !sig.hasRestParameter ? sig.parameters.length : Number.MAX_VALUE);
+                return forEach(sourceLengths, len => len < targetParameterCount);
+            }
+
+            return false;
+        }
+
         /**
          * Detect if the mapper implies an inference context. Specifically, there are 4 possible values
          * for a mapper. Let's go through each one of them:
@@ -11890,12 +11914,6 @@ namespace ts {
                     // If the effective argument type is 'undefined', there is no synthetic type
                     // for the argument. In that case, we should check the argument.
                     if (argType === undefined) {
-                        // If the parameter and argument are both functions and the parameter has fewer arguments than the argument,
-                        // then this signature is not applicable. Exit early to avoid fixing incorrect
-                        // contextual types to the function expression parameters.
-                        if (!reportErrors && isAritySmaller(paramType, arg)) {
-                            return false;
-                        }
                         argType = checkExpressionWithContextualType(arg, paramType, excludeArgument && excludeArgument[i] ? identityMapper : undefined);
                     }
 
@@ -11910,16 +11928,6 @@ namespace ts {
             return true;
         }
 
-        function isAritySmaller(sourceType: Type, target: Expression) {
-            if (isFunctionExpressionOrArrowFunction(target) && isFunctionType(sourceType)) {
-                const sourceSignatures = getSignaturesOfType(sourceType, SignatureKind.Call);
-                const sourceLengths = sourceSignatures.map(sig => !sig.hasRestParameter ? sig.parameters.length : Number.MAX_VALUE);
-                return forEach(sourceLengths, len => len < target.parameters.length);
-            }
-
-            return false;
-        }
-
         /**
          * Returns the this argument in calls like x.f(...) and x[f](...). Undefined otherwise.
          */
diff --git a/tests/baselines/reference/contextualTypingOfTooShortOverloads.types b/tests/baselines/reference/contextualTypingOfTooShortOverloads.types
index 9e306da3e61ef..769bd55d4b57b 100644
--- a/tests/baselines/reference/contextualTypingOfTooShortOverloads.types
+++ b/tests/baselines/reference/contextualTypingOfTooShortOverloads.types
@@ -7,9 +7,9 @@ var use: Overload;
 use((req, res) => {});
 >use((req, res) => {}) : void
 >use : Overload
->(req, res) => {} : (req: number, res: number) => void
->req : number
->res : number
+>(req, res) => {} : (req: any, res: any) => void
+>req : any
+>res : any
 
 interface Overload {
 >Overload : Overload
diff --git a/tests/baselines/reference/genericCallWithOverloadedFunctionTypedArguments.types b/tests/baselines/reference/genericCallWithOverloadedFunctionTypedArguments.types
index c26370a7640a5..ab07e9c880a61 100644
--- a/tests/baselines/reference/genericCallWithOverloadedFunctionTypedArguments.types
+++ b/tests/baselines/reference/genericCallWithOverloadedFunctionTypedArguments.types
@@ -122,8 +122,8 @@ module GenericParameter {
 >'' : ""
 
     var r11 = foo6(<T>(x: T, y?: T) => ''); // any => string (+1 overload)
->r11 : any
->foo6(<T>(x: T, y?: T) => '') : any
+>r11 : { (x: any): string; (x: any, y?: any): string; }
+>foo6(<T>(x: T, y?: T) => '') : { (x: any): string; (x: any, y?: any): string; }
 >foo6 : <T>(cb: { (x: T): string; (x: T, y?: T): string; }) => { (x: T): string; (x: T, y?: T): string; }
 ><T>(x: T, y?: T) => '' : <T>(x: T, y?: T) => string
 >T : T
diff --git a/tests/baselines/reference/partiallyAnnotatedFunctionInferenceError.errors.txt b/tests/baselines/reference/partiallyAnnotatedFunctionInferenceError.errors.txt
index d1e84494fa914..a6a4524592993 100644
--- a/tests/baselines/reference/partiallyAnnotatedFunctionInferenceError.errors.txt
+++ b/tests/baselines/reference/partiallyAnnotatedFunctionInferenceError.errors.txt
@@ -1,6 +1,6 @@
-tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(12,11): error TS2345: Argument of type '(t1: D, t2: C, t3: any) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.
-tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(13,11): error TS2345: Argument of type '(t1: C, t2: D, t3: any) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.
-tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(14,11): error TS2345: Argument of type '(t1: C, t2: C, t3: D) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.
+tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(12,11): error TS2345: Argument of type '(t1: D, t2: any, t3: any) => void' is not assignable to parameter of type '(t: any, t1: any) => void'.
+tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(13,11): error TS2345: Argument of type '(t1: any, t2: D, t3: any) => void' is not assignable to parameter of type '(t: any, t1: any) => void'.
+tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(14,11): error TS2345: Argument of type '(t1: any, t2: any, t3: D) => void' is not assignable to parameter of type '(t: any, t1: any) => void'.
 
 
 ==== tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts (3 errors) ====
@@ -17,11 +17,11 @@ tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partial
     // more args
     testError((t1: D, t2, t3) => {})
               ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2345: Argument of type '(t1: D, t2: C, t3: any) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.
+!!! error TS2345: Argument of type '(t1: D, t2: any, t3: any) => void' is not assignable to parameter of type '(t: any, t1: any) => void'.
     testError((t1, t2: D, t3) => {})
               ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2345: Argument of type '(t1: C, t2: D, t3: any) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.
+!!! error TS2345: Argument of type '(t1: any, t2: D, t3: any) => void' is not assignable to parameter of type '(t: any, t1: any) => void'.
     testError((t1, t2, t3: D) => {})
               ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2345: Argument of type '(t1: C, t2: C, t3: D) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.
+!!! error TS2345: Argument of type '(t1: any, t2: any, t3: D) => void' is not assignable to parameter of type '(t: any, t1: any) => void'.
     
\ No newline at end of file

From 179682610f723b5dfe5660e5162a44046294cf9f Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 28 Oct 2016 08:57:19 -0700
Subject: [PATCH 115/224] isAritySmaller runs later: getNonGenericSignature

---
 src/compiler/checker.ts | 48 +++++++++++++++++------------------------
 1 file changed, 20 insertions(+), 28 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index b188fec8b4d26..474861589d2b1 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -10305,16 +10305,32 @@ namespace ts {
 
         // If the given type is an object or union type, if that type has a single signature, and if
         // that signature is non-generic, return the signature. Otherwise return undefined.
-        function getNonGenericSignature(type: Type): Signature {
+        function getNonGenericSignature(type: Type, node: FunctionExpression | ArrowFunction | MethodDeclaration): Signature {
             const signatures = getSignaturesOfStructuredType(type, SignatureKind.Call);
             if (signatures.length === 1) {
                 const signature = signatures[0];
-                if (!signature.typeParameters) {
+                if (!signature.typeParameters && !isAritySmaller(signature, node)) {
                     return signature;
                 }
             }
         }
 
+        /** If the contextual signature has fewer parameters than the function expression, do not use it */
+        function isAritySmaller(signature: Signature, target: FunctionExpression | ArrowFunction | MethodDeclaration) {
+            let targetParameterCount = 0;
+            for (; targetParameterCount < target.parameters.length; targetParameterCount++) {
+                const param = target.parameters[targetParameterCount];
+                if (param.initializer || param.questionToken || param.dotDotDotToken || isJSDocOptionalParameter(param)) {
+                    break;
+                }
+            }
+            if (target.parameters.length && parameterIsThisKeyword(target.parameters[0])) {
+                targetParameterCount--;
+            }
+            const sourceLength = signature.hasRestParameter ? Number.MAX_VALUE : signature.parameters.length;
+            return sourceLength < targetParameterCount;
+        }
+
         function isFunctionExpressionOrArrowFunction(node: Node): node is FunctionExpression | ArrowFunction {
             return node.kind === SyntaxKind.FunctionExpression || node.kind === SyntaxKind.ArrowFunction;
         }
@@ -10343,17 +10359,13 @@ namespace ts {
             if (!type) {
                 return undefined;
             }
-            // If the contextual signature has fewer parameters than the function expression, do not use it
-            if (isFunctionExpressionOrArrowFunction(node) && isAritySmaller(type, node)) {
-                return undefined;
-            }
             if (!(type.flags & TypeFlags.Union)) {
-                return getNonGenericSignature(type);
+                return getNonGenericSignature(type, node);
             }
             let signatureList: Signature[];
             const types = (<UnionType>type).types;
             for (const current of types) {
-                const signature = getNonGenericSignature(current);
+                const signature = getNonGenericSignature(current, node);
                 if (signature) {
                     if (!signatureList) {
                         // This signature will contribute to contextual union signature
@@ -10381,26 +10393,6 @@ namespace ts {
             return result;
         }
 
-        function isAritySmaller(sourceType: Type, target: FunctionExpression | ArrowFunction) {
-            if (isFunctionType(sourceType)) {
-                let targetParameterCount = 0;
-                for (; targetParameterCount < target.parameters.length; targetParameterCount++) {
-                    const param = target.parameters[targetParameterCount];
-                    if (param.initializer || param.questionToken || param.dotDotDotToken || isJSDocOptionalParameter(param)) {
-                        break;
-                    }
-                }
-                if (target.parameters.length && parameterIsThisKeyword(target.parameters[0])) {
-                    targetParameterCount--;
-                }
-                const sourceSignatures = getSignaturesOfType(sourceType, SignatureKind.Call);
-                const sourceLengths = sourceSignatures.map(sig => !sig.hasRestParameter ? sig.parameters.length : Number.MAX_VALUE);
-                return forEach(sourceLengths, len => len < targetParameterCount);
-            }
-
-            return false;
-        }
-
         /**
          * Detect if the mapper implies an inference context. Specifically, there are 4 possible values
          * for a mapper. Let's go through each one of them:

From 988bf1fc69fbcdbd06e07dd5d988f1d221ab73cf Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 28 Oct 2016 10:24:30 -0700
Subject: [PATCH 116/224] Rename TransformFlags.Experimental -> ESNext

---
 src/compiler/binder.ts              | 4 ++--
 src/compiler/transformers/esnext.ts | 4 ++--
 src/compiler/types.ts               | 8 ++++----
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 0b8f59a82ef71..35844095da46b 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -3160,8 +3160,8 @@ namespace ts {
 
                 if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
                     // If an ObjectLiteralExpression contains a spread element, then it
-                    // is an ES experimental node.
-                    transformFlags |= TransformFlags.AssertExperimental;
+                    // is an ES next node.
+                    transformFlags |= TransformFlags.AssertESNext;
                 }
 
                 break;
diff --git a/src/compiler/transformers/esnext.ts b/src/compiler/transformers/esnext.ts
index 58cf1a1c01aeb..1a8ed7da5eb4a 100644
--- a/src/compiler/transformers/esnext.ts
+++ b/src/compiler/transformers/esnext.ts
@@ -11,10 +11,10 @@ namespace ts {
         }
 
         function visitor(node: Node): VisitResult<Node> {
-            if (node.transformFlags & TransformFlags.Experimental) {
+            if (node.transformFlags & TransformFlags.ESNext) {
                 return visitorWorker(node);
             }
-            else if (node.transformFlags & TransformFlags.ContainsExperimental) {
+            else if (node.transformFlags & TransformFlags.ContainsESNext) {
                 return visitEachChild(node, visitor, context);
             }
             else {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index c9a51a9622baf..e331ebc02f6fa 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -3463,8 +3463,8 @@ namespace ts {
         ContainsTypeScript = 1 << 1,
         Jsx = 1 << 2,
         ContainsJsx = 1 << 3,
-        Experimental = 1 << 4,
-        ContainsExperimental = 1 << 5,
+        ESNext = 1 << 4,
+        ContainsESNext = 1 << 5,
         ES2017 = 1 << 6,
         ContainsES2017 = 1 << 7,
         ES2016 = 1 << 8,
@@ -3498,7 +3498,7 @@ namespace ts {
         // - Bitmasks that are used to assert facts about the syntax of a node and its subtree.
         AssertTypeScript = TypeScript | ContainsTypeScript,
         AssertJsx = Jsx | ContainsJsx,
-        AssertExperimental = Experimental | ContainsExperimental,
+        AssertESNext = ESNext | ContainsESNext,
         AssertES2017 = ES2017 | ContainsES2017,
         AssertES2016 = ES2016 | ContainsES2016,
         AssertES2015 = ES2015 | ContainsES2015,
@@ -3508,7 +3508,7 @@ namespace ts {
         // Scope Exclusions
         // - Bitmasks that exclude flags from propagating out of a specific context
         //   into the subtree flags of their container.
-        NodeExcludes = TypeScript | Jsx | Experimental | ES2017 | ES2016 | ES2015 | DestructuringAssignment | Generator | HasComputedFlags,
+        NodeExcludes = TypeScript | Jsx | ESNext | ES2017 | ES2016 | ES2015 | DestructuringAssignment | Generator | HasComputedFlags,
         ArrowFunctionExcludes = NodeExcludes | ContainsDecorators | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsParameterPropertyAssignments | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,
         FunctionExcludes = NodeExcludes | ContainsDecorators | ContainsDefaultValueAssignments | ContainsCapturedLexicalThis | ContainsLexicalThis | ContainsParameterPropertyAssignments | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,
         ConstructorExcludes = NodeExcludes | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,

From fdb3b6857d0f03693d53868c8a7752ce2801ea7a Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Thu, 27 Oct 2016 14:52:09 -0700
Subject: [PATCH 117/224] enable non-ts extensions in inferred projects by
 default

---
 src/harness/unittests/session.ts              |  3 +-
 .../unittests/tsserverProjectSystem.ts        | 34 +++++++++++++++++++
 src/server/editorServices.ts                  |  3 ++
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/src/harness/unittests/session.ts b/src/harness/unittests/session.ts
index dd9efe51a4aee..05f62c4b9f622 100644
--- a/src/harness/unittests/session.ts
+++ b/src/harness/unittests/session.ts
@@ -150,7 +150,8 @@ namespace ts.server {
                         target: ScriptTarget.ES5,
                         jsx: JsxEmit.React,
                         newLine: NewLineKind.LineFeed,
-                        moduleResolution: ModuleResolutionKind.NodeJs
+                        moduleResolution: ModuleResolutionKind.NodeJs,
+                        allowNonTsExtensions: true // injected by tsserver
                     });
             });
         });
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index 5ac1892157856..870926a8c5595 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -2471,4 +2471,38 @@ namespace ts.projectSystem {
 
         });
     });
+
+    describe("Inferred projects", () => {
+        it("should support files without extensions", () => {
+            const f = {
+                path: "/a/compile",
+                content: "let x = 1"
+            };
+            const host = createServerHost([f]);
+            const session = createSession(host);
+            session.executeCommand(<server.protocol.SetCompilerOptionsForInferredProjectsRequest>{
+                seq: 1,
+                type: "request",
+                command: "compilerOptionsForInferredProjects",
+                arguments: {
+                    options: {
+                        allowJs: true
+                    }
+                }
+            });
+            session.executeCommand(<server.protocol.OpenRequest>{
+                seq: 2,
+                type: "request",
+                command: "open",
+                arguments: {
+                    file: f.path,
+                    fileContent: f.content,
+                    scriptKindName: "JS"
+                }
+            });
+            const projectService = session.getProjectService();
+            checkNumberOfProjects(projectService, { inferredProjects: 1 });
+            checkProjectActualFiles(projectService.inferredProjects[0], [f.path]);
+        });
+    });
 }
\ No newline at end of file
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index f80305efafa52..a02becd87c486 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -298,6 +298,9 @@ namespace ts.server {
 
         setCompilerOptionsForInferredProjects(projectCompilerOptions: protocol.ExternalProjectCompilerOptions): void {
             this.compilerOptionsForInferredProjects = convertCompilerOptions(projectCompilerOptions);
+            // always set 'allowNonTsExtensions' for inferred projects since user cannot configure it from the outside
+            // previously we did not expose a way for user to change these settings and this option was enabled by default
+            this.compilerOptionsForInferredProjects.allowNonTsExtensions = true;
             this.compileOnSaveForInferredProjects = projectCompilerOptions.compileOnSave;
             for (const proj of this.inferredProjects) {
                 proj.setCompilerOptions(this.compilerOptionsForInferredProjects);

From fc93e8f6f4affbde41f6e152b9d2bdd3e92b634d Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Fri, 28 Oct 2016 14:17:01 -0700
Subject: [PATCH 118/224] update CFG to properly handle do statements

---
 src/compiler/binder.ts                        | 16 ++++++---
 .../reference/doWhileUnreachableCode.js       | 26 ++++++++++++++
 .../reference/doWhileUnreachableCode.symbols  | 22 ++++++++++++
 .../reference/doWhileUnreachableCode.types    | 34 +++++++++++++++++++
 .../cases/compiler/doWhileUnreachableCode.ts  | 12 +++++++
 5 files changed, 106 insertions(+), 4 deletions(-)
 create mode 100644 tests/baselines/reference/doWhileUnreachableCode.js
 create mode 100644 tests/baselines/reference/doWhileUnreachableCode.symbols
 create mode 100644 tests/baselines/reference/doWhileUnreachableCode.types
 create mode 100644 tests/cases/compiler/doWhileUnreachableCode.ts

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 9c2c749e112a6..613a50c6d3d61 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -892,8 +892,13 @@ namespace ts {
 
         function bindDoStatement(node: DoStatement): void {
             const preDoLabel = createLoopLabel();
-            const preConditionLabel = createBranchLabel();
-            const postDoLabel = createBranchLabel();
+            const enclosingLabeledStatement = node.parent.kind === SyntaxKind.LabeledStatement
+                ? lastOrUndefined(activeLabels)
+                : undefined;
+            // if do statement is wrapped in labeled statement then target labels for break/continue with or without 
+            // label should be the same 
+            const preConditionLabel = enclosingLabeledStatement ? enclosingLabeledStatement.continueTarget : createBranchLabel();
+            const postDoLabel = enclosingLabeledStatement ? enclosingLabeledStatement.breakTarget : createBranchLabel();
             addAntecedent(preDoLabel, currentFlow);
             currentFlow = preDoLabel;
             bindIterativeStatement(node.statement, postDoLabel, preConditionLabel);
@@ -1111,8 +1116,11 @@ namespace ts {
             if (!activeLabel.referenced && !options.allowUnusedLabels) {
                 file.bindDiagnostics.push(createDiagnosticForNode(node.label, Diagnostics.Unused_label));
             }
-            addAntecedent(postStatementLabel, currentFlow);
-            currentFlow = finishFlowLabel(postStatementLabel);
+            if (!node.statement || node.statement.kind !== SyntaxKind.DoStatement) {
+                // do statement sets current flow inside bindDoStatement
+                addAntecedent(postStatementLabel, currentFlow);
+                currentFlow = finishFlowLabel(postStatementLabel);
+            }
         }
 
         function bindDestructuringTargetFlow(node: Expression) {
diff --git a/tests/baselines/reference/doWhileUnreachableCode.js b/tests/baselines/reference/doWhileUnreachableCode.js
new file mode 100644
index 0000000000000..3434a93f52dfb
--- /dev/null
+++ b/tests/baselines/reference/doWhileUnreachableCode.js
@@ -0,0 +1,26 @@
+//// [doWhileUnreachableCode.ts]
+function test() {
+    let foo = 0;
+    testLoop: do {
+        foo++;
+        continue testLoop;
+    } while (function() {
+        var x = 1;
+        return false;
+    }());
+
+    return foo;
+}
+
+//// [doWhileUnreachableCode.js]
+function test() {
+    var foo = 0;
+    testLoop: do {
+        foo++;
+        continue testLoop;
+    } while (function () {
+        var x = 1;
+        return false;
+    }());
+    return foo;
+}
diff --git a/tests/baselines/reference/doWhileUnreachableCode.symbols b/tests/baselines/reference/doWhileUnreachableCode.symbols
new file mode 100644
index 0000000000000..571976490c37d
--- /dev/null
+++ b/tests/baselines/reference/doWhileUnreachableCode.symbols
@@ -0,0 +1,22 @@
+=== tests/cases/compiler/doWhileUnreachableCode.ts ===
+function test() {
+>test : Symbol(test, Decl(doWhileUnreachableCode.ts, 0, 0))
+
+    let foo = 0;
+>foo : Symbol(foo, Decl(doWhileUnreachableCode.ts, 1, 7))
+
+    testLoop: do {
+        foo++;
+>foo : Symbol(foo, Decl(doWhileUnreachableCode.ts, 1, 7))
+
+        continue testLoop;
+    } while (function() {
+        var x = 1;
+>x : Symbol(x, Decl(doWhileUnreachableCode.ts, 6, 11))
+
+        return false;
+    }());
+
+    return foo;
+>foo : Symbol(foo, Decl(doWhileUnreachableCode.ts, 1, 7))
+}
diff --git a/tests/baselines/reference/doWhileUnreachableCode.types b/tests/baselines/reference/doWhileUnreachableCode.types
new file mode 100644
index 0000000000000..0c176dda79983
--- /dev/null
+++ b/tests/baselines/reference/doWhileUnreachableCode.types
@@ -0,0 +1,34 @@
+=== tests/cases/compiler/doWhileUnreachableCode.ts ===
+function test() {
+>test : () => number
+
+    let foo = 0;
+>foo : number
+>0 : 0
+
+    testLoop: do {
+>testLoop : any
+
+        foo++;
+>foo++ : number
+>foo : number
+
+        continue testLoop;
+>testLoop : any
+
+    } while (function() {
+>function() {        var x = 1;        return false;    }() : boolean
+>function() {        var x = 1;        return false;    } : () => boolean
+
+        var x = 1;
+>x : number
+>1 : 1
+
+        return false;
+>false : false
+
+    }());
+
+    return foo;
+>foo : number
+}
diff --git a/tests/cases/compiler/doWhileUnreachableCode.ts b/tests/cases/compiler/doWhileUnreachableCode.ts
new file mode 100644
index 0000000000000..e4b47fc1afbab
--- /dev/null
+++ b/tests/cases/compiler/doWhileUnreachableCode.ts
@@ -0,0 +1,12 @@
+function test() {
+    let foo = 0;
+    testLoop: do {
+        foo++;
+        continue testLoop;
+    } while (function() {
+        var x = 1;
+        return false;
+    }());
+
+    return foo;
+}
\ No newline at end of file

From 73c59bbf859a22424871ced74997b15e1c6d2f60 Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Fri, 28 Oct 2016 14:43:08 -0700
Subject: [PATCH 119/224] do not inline async IIFEs in control flow graph

---
 src/compiler/binder.ts                      |  4 +--
 tests/baselines/reference/asyncIIFE.js      | 28 +++++++++++++++++++++
 tests/baselines/reference/asyncIIFE.symbols | 16 ++++++++++++
 tests/baselines/reference/asyncIIFE.types   | 25 ++++++++++++++++++
 tests/cases/compiler/asyncIIFE.ts           | 10 ++++++++
 5 files changed, 81 insertions(+), 2 deletions(-)
 create mode 100644 tests/baselines/reference/asyncIIFE.js
 create mode 100644 tests/baselines/reference/asyncIIFE.symbols
 create mode 100644 tests/baselines/reference/asyncIIFE.types
 create mode 100644 tests/cases/compiler/asyncIIFE.ts

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 447a7625d384e..c0466e7871ab9 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -490,8 +490,8 @@ namespace ts {
                 const saveReturnTarget = currentReturnTarget;
                 const saveActiveLabels = activeLabels;
                 const saveHasExplicitReturn = hasExplicitReturn;
-                const isIIFE = containerFlags & ContainerFlags.IsFunctionExpression && !!getImmediatelyInvokedFunctionExpression(node);
-                // An IIFE is considered part of the containing control flow. Return statements behave
+                const isIIFE = containerFlags & ContainerFlags.IsFunctionExpression && !hasModifier(node, ModifierFlags.Async) && !!getImmediatelyInvokedFunctionExpression(node);
+                // A non-async IIFE is considered part of the containing control flow. Return statements behave
                 // similarly to break statements that exit to a label just past the statement body.
                 if (isIIFE) {
                     currentReturnTarget = createBranchLabel();
diff --git a/tests/baselines/reference/asyncIIFE.js b/tests/baselines/reference/asyncIIFE.js
new file mode 100644
index 0000000000000..79779af62f355
--- /dev/null
+++ b/tests/baselines/reference/asyncIIFE.js
@@ -0,0 +1,28 @@
+//// [asyncIIFE.ts]
+
+function f1() {
+    (async () => {
+        await 10
+        throw new Error();
+    })();
+
+    var x = 1;
+}
+
+
+//// [asyncIIFE.js]
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments)).next());
+    });
+};
+function f1() {
+    (() => __awaiter(this, void 0, void 0, function* () {
+        yield 10;
+        throw new Error();
+    }))();
+    var x = 1;
+}
diff --git a/tests/baselines/reference/asyncIIFE.symbols b/tests/baselines/reference/asyncIIFE.symbols
new file mode 100644
index 0000000000000..92eb054bff04a
--- /dev/null
+++ b/tests/baselines/reference/asyncIIFE.symbols
@@ -0,0 +1,16 @@
+=== tests/cases/compiler/asyncIIFE.ts ===
+
+function f1() {
+>f1 : Symbol(f1, Decl(asyncIIFE.ts, 0, 0))
+
+    (async () => {
+        await 10
+        throw new Error();
+>Error : Symbol(Error, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+    })();
+
+    var x = 1;
+>x : Symbol(x, Decl(asyncIIFE.ts, 7, 7))
+}
+
diff --git a/tests/baselines/reference/asyncIIFE.types b/tests/baselines/reference/asyncIIFE.types
new file mode 100644
index 0000000000000..e49ab96681fed
--- /dev/null
+++ b/tests/baselines/reference/asyncIIFE.types
@@ -0,0 +1,25 @@
+=== tests/cases/compiler/asyncIIFE.ts ===
+
+function f1() {
+>f1 : () => void
+
+    (async () => {
+>(async () => {        await 10        throw new Error();    })() : Promise<never>
+>(async () => {        await 10        throw new Error();    }) : () => Promise<never>
+>async () => {        await 10        throw new Error();    } : () => Promise<never>
+
+        await 10
+>await 10 : 10
+>10 : 10
+
+        throw new Error();
+>new Error() : Error
+>Error : ErrorConstructor
+
+    })();
+
+    var x = 1;
+>x : number
+>1 : 1
+}
+
diff --git a/tests/cases/compiler/asyncIIFE.ts b/tests/cases/compiler/asyncIIFE.ts
new file mode 100644
index 0000000000000..904476d855c64
--- /dev/null
+++ b/tests/cases/compiler/asyncIIFE.ts
@@ -0,0 +1,10 @@
+// @target: ES6
+
+function f1() {
+    (async () => {
+        await 10
+        throw new Error();
+    })();
+
+    var x = 1;
+}

From 8d87971feebff65ed38562202e6e0d81b241b6e4 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Fri, 28 Oct 2016 15:35:15 -0700
Subject: [PATCH 120/224] Minor fixes

---
 src/compiler/checker.ts | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 40e5a890f2ec6..a556814aedda8 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5744,7 +5744,7 @@ namespace ts {
 
         function getIndexedAccessType(objectType: Type, indexType: Type, errorNode?: Node) {
             if (indexType.flags & TypeFlags.TypeParameter) {
-                if (!isTypeAssignableTo(getConstraintOfTypeParameter(<TypeParameter>indexType), getIndexType(objectType))) {
+                if (!isTypeAssignableTo(getConstraintOfTypeParameter(<TypeParameter>indexType) || emptyObjectType, getIndexType(objectType))) {
                     if (errorNode) {
                         error(errorNode, Diagnostics.Type_0_is_not_constrained_to_keyof_1, typeToString(indexType), typeToString(objectType));
                     }
@@ -11549,9 +11549,8 @@ namespace ts {
                 return objectType;
             }
 
-            if (indexType.flags & TypeFlags.TypeParameter &&
-                isTypeAssignableTo(getConstraintOfTypeParameter(<TypeParameter>indexType), getIndexType(objectType))) {
-                return getIndexedAccessType(objectType, indexType);
+            if (indexType.flags & TypeFlags.TypeParameter) {
+                return getIndexedAccessType(objectType, indexType, node.argumentExpression);
             }
 
             objectType = getApparentType(objectType);

From 44ce59d1d8c0148e7f32dfa55ea65a2b394bfbb9 Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Sat, 29 Oct 2016 15:57:51 -0700
Subject: [PATCH 121/224] cache type for empty type literal (#11934)

cache type for empty type literal
---
 src/compiler/checker.ts | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 9c4ed1128dcb4..704018627b24e 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -138,6 +138,11 @@ namespace ts {
         const silentNeverType = createIntrinsicType(TypeFlags.Never, "never");
 
         const emptyObjectType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
+
+        const emptyTypeLiteralSymbol = createSymbol(SymbolFlags.TypeLiteral | SymbolFlags.Transient, "__type");
+        emptyTypeLiteralSymbol.members = createMap<Symbol>();
+        const emptyTypeLiteralType = createAnonymousType(emptyTypeLiteralSymbol, emptySymbols, emptyArray, emptyArray, undefined, undefined);
+
         const emptyGenericType = <GenericType><ObjectType>createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
         emptyGenericType.instantiations = createMap<TypeReference>();
 
@@ -5696,10 +5701,15 @@ namespace ts {
             const links = getNodeLinks(node);
             if (!links.resolvedType) {
                 // Deferred resolution of members is handled by resolveObjectTypeMembers
-                const type = createObjectType(ObjectFlags.Anonymous, node.symbol);
-                type.aliasSymbol = aliasSymbol;
-                type.aliasTypeArguments = aliasTypeArguments;
-                links.resolvedType = type;
+                if (isEmpty(node.symbol.members) && !aliasSymbol && !aliasTypeArguments) {
+                    links.resolvedType = emptyTypeLiteralType;
+                }
+                else {
+                    const type = createObjectType(ObjectFlags.Anonymous, node.symbol);
+                    type.aliasSymbol = aliasSymbol;
+                    type.aliasTypeArguments = aliasTypeArguments;
+                    links.resolvedType = type;
+                }
             }
             return links.resolvedType;
         }
@@ -6036,6 +6046,9 @@ namespace ts {
         }
 
         function isSymbolInScopeOfMappedTypeParameter(symbol: Symbol, mapper: TypeMapper) {
+            if (!(symbol.declarations && symbol.declarations.length)) {
+                return false;
+            }
             const mappedTypes = mapper.mappedTypes;
             // Starting with the parent of the symbol's declaration, check if the mapper maps any of
             // the type parameters introduced by enclosing declarations. We just pick the first

From 5515dcea34d1ff584467ad842ffb4c979f781a7f Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sun, 30 Oct 2016 16:01:15 -0700
Subject: [PATCH 122/224] Improved error messages for invalid assignments to
 identifiers

---
 src/compiler/binder.ts               |  4 +-
 src/compiler/checker.ts              | 81 ++++++++++++++++------------
 src/compiler/diagnosticMessages.json |  8 +++
 src/compiler/types.ts                |  4 --
 src/compiler/utilities.ts            | 56 ++++++++++++-------
 5 files changed, 94 insertions(+), 59 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index c05d0135f1448..801bd2c35babb 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -1192,9 +1192,9 @@ namespace ts {
             }
             else {
                 forEachChild(node, bind);
-                if (operator === SyntaxKind.EqualsToken && !isAssignmentTarget(node)) {
+                if (isAssignmentOperator(operator) && !isAssignmentTarget(node)) {
                     bindAssignmentTargetFlow(node.left);
-                    if (node.left.kind === SyntaxKind.ElementAccessExpression) {
+                    if (operator === SyntaxKind.EqualsToken && node.left.kind === SyntaxKind.ElementAccessExpression) {
                         const elementAccess = <ElementAccessExpression>node.left;
                         if (isNarrowableOperand(elementAccess.expression)) {
                             currentFlow = createFlowArrayMutation(currentFlow, node);
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index a556814aedda8..5e23f56b947fa 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -8851,7 +8851,7 @@ namespace ts {
                 // Assignments only narrow the computed type if the declared type is a union type. Thus, we
                 // only need to evaluate the assigned type if the declared type is a union type.
                 if (isMatchingReference(reference, node)) {
-                    if (node.parent.kind === SyntaxKind.PrefixUnaryExpression || node.parent.kind === SyntaxKind.PostfixUnaryExpression) {
+                    if (getAssignmentTargetKind(node) === AssignmentKind.Compound) {
                         const flowType = getTypeAtFlowNode(flow.antecedent);
                         return createFlowType(getBaseTypeOfLiteralType(getTypeFromFlowType(flowType)), isIncomplete(flowType));
                     }
@@ -9298,10 +9298,10 @@ namespace ts {
                     }
                 }
                 else {
-                    const invokedExpression = skipParenthesizedNodes(callExpression.expression);
+                    const invokedExpression = skipParentheses(callExpression.expression);
                     if (invokedExpression.kind === SyntaxKind.ElementAccessExpression || invokedExpression.kind === SyntaxKind.PropertyAccessExpression) {
                         const accessExpression = invokedExpression as ElementAccessExpression | PropertyAccessExpression;
-                        const possibleReference = skipParenthesizedNodes(accessExpression.expression);
+                        const possibleReference = skipParentheses(accessExpression.expression);
                         if (isMatchingReference(reference, possibleReference)) {
                             return getNarrowedType(type, predicate.type, assumeTrue);
                         }
@@ -9361,13 +9361,6 @@ namespace ts {
             return getTypeOfSymbol(symbol);
         }
 
-        function skipParenthesizedNodes(expression: Expression): Expression {
-            while (expression.kind === SyntaxKind.ParenthesizedExpression) {
-                expression = (expression as ParenthesizedExpression).expression;
-            }
-            return expression;
-        }
-
         function getControlFlowContainer(node: Node): Node {
             while (true) {
                 node = node.parent;
@@ -9425,6 +9418,9 @@ namespace ts {
 
         function checkIdentifier(node: Identifier): Type {
             const symbol = getResolvedSymbol(node);
+            if (symbol === unknownSymbol) {
+                return unknownType;
+            }
 
             // As noted in ECMAScript 6 language spec, arrow functions never have an arguments objects.
             // Although in down-level emit of arrow function, we emit it using function expression which means that
@@ -9446,6 +9442,7 @@ namespace ts {
                 if (node.flags & NodeFlags.AwaitContext) {
                     getNodeLinks(container).flags |= NodeCheckFlags.CaptureArguments;
                 }
+                return getTypeOfSymbol(symbol);
             }
 
             if (symbol.flags & SymbolFlags.Alias && !isInTypeQuery(node) && !isConstEnumOrConstEnumOnlyModule(resolveAlias(symbol))) {
@@ -9498,9 +9495,22 @@ namespace ts {
 
             const type = getTypeOfSymbol(localOrExportSymbol);
             const declaration = localOrExportSymbol.valueDeclaration;
+            const assignmentKind = getAssignmentTargetKind(node);
+
+            if (assignmentKind) {
+                if (!(localOrExportSymbol.flags & SymbolFlags.Variable)) {
+                    error(node, Diagnostics.Cannot_assign_to_0_because_it_is_not_a_variable, symbolToString(symbol));
+                    return unknownType;
+                }
+                if (isReadonlySymbol(localOrExportSymbol)) {
+                    error(node, Diagnostics.Cannot_assign_to_0_because_it_is_a_constant_or_a_read_only_property, symbolToString(symbol));
+                    return unknownType;
+                }
+            }
+
             // We only narrow variables and parameters occurring in a non-assignment position. For all other
             // entities we simply return the declared type.
-            if (!(localOrExportSymbol.flags & SymbolFlags.Variable) || isAssignmentTarget(node) || !declaration) {
+            if (!(localOrExportSymbol.flags & SymbolFlags.Variable) || assignmentKind === AssignmentKind.Definite || !declaration) {
                 return type;
             }
             // The declaration container is the innermost function that encloses the declaration of the variable
@@ -9542,7 +9552,7 @@ namespace ts {
                 // Return the declared type to reduce follow-on errors
                 return type;
             }
-            return flowType;
+            return assignmentKind ? getBaseTypeOfLiteralType(flowType) : flowType;
         }
 
         function isInsideFunction(node: Node, threshold: Node): boolean {
@@ -11397,6 +11407,20 @@ namespace ts {
             return checkPropertyAccessExpressionOrQualifiedName(node, node.left, node.right);
         }
 
+        function reportNonexistentProperty(propNode: Identifier, containingType: Type) {
+            let errorInfo: DiagnosticMessageChain;
+            if (containingType.flags & TypeFlags.Union && !(containingType.flags & TypeFlags.Primitive)) {
+                for (const subtype of (containingType as UnionType).types) {
+                    if (!getPropertyOfType(subtype, propNode.text)) {
+                        errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1, declarationNameToString(propNode), typeToString(subtype));
+                        break;
+                    }
+                }
+            }
+            errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1, declarationNameToString(propNode), typeToString(containingType));
+            diagnostics.add(createDiagnosticForNodeFromMessageChain(propNode, errorInfo));
+        }
+
         function checkPropertyAccessExpressionOrQualifiedName(node: PropertyAccessExpression | QualifiedName, left: Expression | QualifiedName, right: Identifier) {
             const type = checkNonNullExpression(left);
             if (isTypeAny(type) || type === silentNeverType) {
@@ -11445,20 +11469,6 @@ namespace ts {
                 return propType;
             }
             return getFlowTypeOfReference(node, propType, /*assumeInitialized*/ true, /*flowContainer*/ undefined);
-
-            function reportNonexistentProperty(propNode: Identifier, containingType: Type) {
-                let errorInfo: DiagnosticMessageChain;
-                if (containingType.flags & TypeFlags.Union && !(containingType.flags & TypeFlags.Primitive)) {
-                    for (const subtype of (containingType as UnionType).types) {
-                        if (!getPropertyOfType(subtype, propNode.text)) {
-                            errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1, declarationNameToString(propNode), typeToString(subtype));
-                            break;
-                        }
-                    }
-                }
-                errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1, declarationNameToString(propNode), typeToString(containingType));
-                diagnostics.add(createDiagnosticForNodeFromMessageChain(propNode, errorInfo));
-            }
         }
 
         function isValidPropertyAccess(node: PropertyAccessExpression | QualifiedName, propertyName: string): boolean {
@@ -11505,7 +11515,7 @@ namespace ts {
          * that references a for-in variable for an object with numeric property names.
          */
         function isForInVariableForNumericPropertyNames(expr: Expression) {
-            const e = skipParenthesizedNodes(expr);
+            const e = skipParentheses(expr);
             if (e.kind === SyntaxKind.Identifier) {
                 const symbol = getResolvedSymbol(<Identifier>e);
                 if (symbol.flags & SymbolFlags.Variable) {
@@ -13486,7 +13496,7 @@ namespace ts {
 
         function isReferenceThroughNamespaceImport(expr: Expression): boolean {
             if (expr.kind === SyntaxKind.PropertyAccessExpression || expr.kind === SyntaxKind.ElementAccessExpression) {
-                const node = skipParenthesizedNodes((expr as PropertyAccessExpression | ElementAccessExpression).expression);
+                const node = skipParentheses((expr as PropertyAccessExpression | ElementAccessExpression).expression);
                 if (node.kind === SyntaxKind.Identifier) {
                     const symbol = getNodeLinks(node).resolvedSymbol;
                     if (symbol.flags & SymbolFlags.Alias) {
@@ -13500,11 +13510,14 @@ namespace ts {
 
         function checkReferenceExpression(expr: Expression, invalidReferenceMessage: DiagnosticMessage, constantVariableMessage: DiagnosticMessage): boolean {
             // References are combinations of identifiers, parentheses, and property accesses.
-            const node = skipParenthesizedNodes(expr);
+            const node = skipParentheses(expr);
             if (node.kind !== SyntaxKind.Identifier && node.kind !== SyntaxKind.PropertyAccessExpression && node.kind !== SyntaxKind.ElementAccessExpression) {
                 error(expr, invalidReferenceMessage);
                 return false;
             }
+            if (node.kind === SyntaxKind.Identifier) {
+                return true;
+            }
             // Because we get the symbol from the resolvedSymbol property, it might be of kind
             // SymbolFlags.ExportValue. In this case it is necessary to get the actual export
             // symbol, which will have the correct flags set on it.
@@ -13514,10 +13527,10 @@ namespace ts {
                 if (symbol !== unknownSymbol && symbol !== argumentsSymbol) {
                     // Only variables (and not functions, classes, namespaces, enum objects, or enum members)
                     // are considered references when referenced using a simple identifier.
-                    if (node.kind === SyntaxKind.Identifier && !(symbol.flags & SymbolFlags.Variable)) {
-                        error(expr, invalidReferenceMessage);
-                        return false;
-                    }
+                    // if (node.kind === SyntaxKind.Identifier && !(symbol.flags & SymbolFlags.Variable)) {
+                    //     error(expr, invalidReferenceMessage);
+                    //     return false;
+                    // }
                     if (isReferenceToReadonlyEntity(node, symbol) || isReferenceThroughNamespaceImport(node)) {
                         error(expr, constantVariableMessage);
                         return false;
@@ -14255,7 +14268,7 @@ namespace ts {
         }
 
         function isTypeAssertion(node: Expression) {
-            node = skipParenthesizedNodes(node);
+            node = skipParentheses(node);
             return node.kind === SyntaxKind.TypeAssertionExpression || node.kind === SyntaxKind.AsExpression;
         }
 
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index c08245eee91a6..85068a4fad5c8 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1763,6 +1763,14 @@
         "category": "Error",
         "code": 2538
     },
+    "Cannot assign to '{0}' because it is not a variable.": {
+        "category": "Error",
+        "code": 2539
+    },
+    "Cannot assign to '{0}' because it is a constant or a read-only property.": {
+        "category": "Error",
+        "code": 2540
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 2ea4dc71d886d..041c0beb07566 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -956,10 +956,6 @@ namespace ts {
         operator: PostfixUnaryOperator;
     }
 
-    export interface PostfixExpression extends UnaryExpression {
-        _postfixExpressionBrand: any;
-    }
-
     export interface LeftHandSideExpression extends IncrementExpression {
         _leftHandSideExpressionBrand: any;
     }
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 87f6cd5e4aa79..f9fe30b4e534c 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -1624,29 +1624,47 @@ namespace ts {
         return node && node.dotDotDotToken !== undefined;
     }
 
+    export const enum AssignmentKind {
+        None, Definite, Compound
+    }
+
+    export function getAssignmentTargetKind(node: Node): AssignmentKind {
+        let parent = node.parent;
+        while (true) {
+            switch (parent.kind) {
+                case SyntaxKind.BinaryExpression:
+                    const binaryOperator = (<BinaryExpression>parent).operatorToken.kind;
+                    return isAssignmentOperator(binaryOperator) && (<BinaryExpression>parent).left === node ?
+                        binaryOperator === SyntaxKind.EqualsToken ? AssignmentKind.Definite : AssignmentKind.Compound :
+                        AssignmentKind.None;
+                case SyntaxKind.PrefixUnaryExpression:
+                case SyntaxKind.PostfixUnaryExpression:
+                    const unaryOperator = (<PrefixUnaryExpression | PostfixUnaryExpression>parent).operator;
+                    return unaryOperator === SyntaxKind.PlusPlusToken || unaryOperator === SyntaxKind.MinusMinusToken ? AssignmentKind.Compound : AssignmentKind.None;
+                case SyntaxKind.ForInStatement:
+                case SyntaxKind.ForOfStatement:
+                    return (<ForInStatement | ForOfStatement>parent).initializer === node ? AssignmentKind.Definite : AssignmentKind.None;
+                case SyntaxKind.ParenthesizedExpression:
+                case SyntaxKind.ArrayLiteralExpression:
+                case SyntaxKind.SpreadElementExpression:
+                    node = parent;
+                    break;
+                case SyntaxKind.PropertyAssignment:
+                case SyntaxKind.ShorthandPropertyAssignment:
+                    node = parent.parent;
+                    break;
+                default:
+                    return AssignmentKind.None;
+            }
+            parent = node.parent;
+        }
+    }
+
     // A node is an assignment target if it is on the left hand side of an '=' token, if it is parented by a property
     // assignment in an object literal that is an assignment target, or if it is parented by an array literal that is
     // an assignment target. Examples include 'a = xxx', '{ p: a } = xxx', '[{ p: a}] = xxx'.
     export function isAssignmentTarget(node: Node): boolean {
-        while (node.parent.kind === SyntaxKind.ParenthesizedExpression) {
-            node = node.parent;
-        }
-        while (true) {
-            const parent = node.parent;
-            if (parent.kind === SyntaxKind.ArrayLiteralExpression || parent.kind === SyntaxKind.SpreadElementExpression) {
-                node = parent;
-                continue;
-            }
-            if (parent.kind === SyntaxKind.PropertyAssignment || parent.kind === SyntaxKind.ShorthandPropertyAssignment) {
-                node = parent.parent;
-                continue;
-            }
-            return parent.kind === SyntaxKind.BinaryExpression &&
-                isAssignmentOperator((<BinaryExpression>parent).operatorToken.kind) &&
-                (<BinaryExpression>parent).left === node ||
-                (parent.kind === SyntaxKind.ForInStatement || parent.kind === SyntaxKind.ForOfStatement) &&
-                (<ForInStatement | ForOfStatement>parent).initializer === node;
-        }
+        return getAssignmentTargetKind(node) !== AssignmentKind.None;
     }
 
     export function isNodeDescendantOf(node: Node, ancestor: Node): boolean {

From 550be9c8cd3f6745411aa31070738f83b9768a88 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sun, 30 Oct 2016 16:01:42 -0700
Subject: [PATCH 123/224] Accept new baselines

---
 .../reference/arithAssignTyping.errors.txt    | 50 ++++++------
 .../reference/assignAnyToEveryType.errors.txt |  4 +-
 .../reference/assignToEnum.errors.txt         |  8 +-
 .../assignToExistingClass.errors.txt          |  4 +-
 .../reference/assignmentLHSIsValue.errors.txt | 40 +++++-----
 .../reference/assignmentToFunction.errors.txt |  8 +-
 ...nmentToParenthesizedIdentifiers.errors.txt | 44 +++++-----
 .../assignmentToReferenceTypes.errors.txt     | 12 +--
 .../reference/assignments.errors.txt          | 12 +--
 .../compoundAssignmentLHSIsValue.errors.txt   | 80 +++++++++----------
 ...onentiationAssignmentLHSIsValue.errors.txt | 40 +++++-----
 .../reference/concatClassAndString.errors.txt |  4 +-
 .../constDeclarations-access.errors.txt       |  4 +-
 .../constDeclarations-access2.errors.txt      | 70 ++++++++--------
 .../constDeclarations-errors.errors.txt       |  4 +-
 ...thAnyOtherTypeInvalidOperations.errors.txt | 24 +++---
 ...orWithEnumTypeInvalidOperations.errors.txt | 32 ++++----
 .../reference/enumLiteralTypes1.types         |  4 +-
 .../reference/enumLiteralTypes2.types         |  2 +-
 tests/baselines/reference/for-of2.errors.txt  |  4 +-
 .../importsImplicitlyReadonly.errors.txt      |  8 +-
 ...thAnyOtherTypeInvalidOperations.errors.txt | 24 +++---
 ...orWithEnumTypeInvalidOperations.errors.txt | 32 ++++----
 .../invalidBooleanAssignments.errors.txt      |  8 +-
 .../invalidNumberAssignments.errors.txt       |  8 +-
 .../invalidStringAssignments.errors.txt       |  8 +-
 .../invalidUndefinedAssignments.errors.txt    | 16 ++--
 .../invalidVoidAssignments.errors.txt         |  8 +-
 .../nullAssignedToUndefined.errors.txt        |  4 +-
 .../reference/numericLiteralTypes1.types      |  4 +-
 .../reference/numericLiteralTypes2.types      |  4 +-
 .../parserStrictMode3-negative.errors.txt     |  4 +-
 .../reference/parserStrictMode3.errors.txt    |  4 +-
 .../reference/parserStrictMode5.errors.txt    |  6 +-
 .../parserStrictMode6-negative.errors.txt     |  4 +-
 .../reference/parserStrictMode6.errors.txt    |  4 +-
 .../reference/parserStrictMode7.errors.txt    |  4 +-
 .../reference/redefineArray.errors.txt        |  4 +-
 .../reference/sourceMapValidationIfElse.types |  6 +-
 .../reference/sourceMapValidationSwitch.types |  8 +-
 .../reference/sourceMapValidationWhile.types  |  4 +-
 .../unaryOperatorsInStrictMode.errors.txt     | 16 ++--
 .../reference/validNullAssignments.errors.txt | 12 +--
 43 files changed, 325 insertions(+), 325 deletions(-)

diff --git a/tests/baselines/reference/arithAssignTyping.errors.txt b/tests/baselines/reference/arithAssignTyping.errors.txt
index 10f34e94012f2..12b5b52698dbf 100644
--- a/tests/baselines/reference/arithAssignTyping.errors.txt
+++ b/tests/baselines/reference/arithAssignTyping.errors.txt
@@ -1,15 +1,15 @@
-tests/cases/compiler/arithAssignTyping.ts(3,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/compiler/arithAssignTyping.ts(4,1): error TS2365: Operator '+=' cannot be applied to types 'typeof f' and '1'.
-tests/cases/compiler/arithAssignTyping.ts(5,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(6,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(7,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(8,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(9,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(10,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(11,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(12,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(13,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(14,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+tests/cases/compiler/arithAssignTyping.ts(3,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(4,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(5,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(6,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(7,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(8,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(9,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(10,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(11,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(12,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(13,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(14,1): error TS2539: Cannot assign to 'f' because it is not a variable.
 
 
 ==== tests/cases/compiler/arithAssignTyping.ts (12 errors) ====
@@ -17,37 +17,37 @@ tests/cases/compiler/arithAssignTyping.ts(14,1): error TS2362: The left-hand sid
     
     f += ''; // error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f += 1; // error
-    ~~~~~~
-!!! error TS2365: Operator '+=' cannot be applied to types 'typeof f' and '1'.
+    ~
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f -= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f *= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f /= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f %= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f &= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f |= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f <<= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f >>= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f >>>= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f ^= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
\ No newline at end of file
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
\ No newline at end of file
diff --git a/tests/baselines/reference/assignAnyToEveryType.errors.txt b/tests/baselines/reference/assignAnyToEveryType.errors.txt
index 9aae6efc37e44..86efb0c3019de 100644
--- a/tests/baselines/reference/assignAnyToEveryType.errors.txt
+++ b/tests/baselines/reference/assignAnyToEveryType.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/types/any/assignAnyToEveryType.ts(41,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/any/assignAnyToEveryType.ts(41,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 
 
 ==== tests/cases/conformance/types/any/assignAnyToEveryType.ts (1 errors) ====
@@ -44,7 +44,7 @@ tests/cases/conformance/types/any/assignAnyToEveryType.ts(41,1): error TS2364: I
     
     M = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     function k<T>(a: T) {
         a = x;
diff --git a/tests/baselines/reference/assignToEnum.errors.txt b/tests/baselines/reference/assignToEnum.errors.txt
index d50daa3099f6a..c907db7a8bfbf 100644
--- a/tests/baselines/reference/assignToEnum.errors.txt
+++ b/tests/baselines/reference/assignToEnum.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/compiler/assignToEnum.ts(2,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/compiler/assignToEnum.ts(3,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/assignToEnum.ts(2,1): error TS2539: Cannot assign to 'A' because it is not a variable.
+tests/cases/compiler/assignToEnum.ts(3,1): error TS2539: Cannot assign to 'A' because it is not a variable.
 tests/cases/compiler/assignToEnum.ts(4,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
 tests/cases/compiler/assignToEnum.ts(5,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
 
@@ -8,10 +8,10 @@ tests/cases/compiler/assignToEnum.ts(5,1): error TS2450: Left-hand side of assig
     enum A { foo, bar }
     A = undefined;  // invalid LHS
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'A' because it is not a variable.
     A = A.bar;      // invalid LHS
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'A' because it is not a variable.
     A.foo = 1;      // invalid LHS
     ~~~~~
 !!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
diff --git a/tests/baselines/reference/assignToExistingClass.errors.txt b/tests/baselines/reference/assignToExistingClass.errors.txt
index 6a377df5b0c56..5f7faac9e64d7 100644
--- a/tests/baselines/reference/assignToExistingClass.errors.txt
+++ b/tests/baselines/reference/assignToExistingClass.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/assignToExistingClass.ts(8,13): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/assignToExistingClass.ts(8,13): error TS2539: Cannot assign to 'Mocked' because it is not a variable.
 
 
 ==== tests/cases/compiler/assignToExistingClass.ts (1 errors) ====
@@ -11,7 +11,7 @@ tests/cases/compiler/assignToExistingClass.ts(8,13): error TS2364: Invalid left-
             willThrowError() {
                 Mocked = Mocked || function () { // => Error: Invalid left-hand side of assignment expression.
                 ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'Mocked' because it is not a variable.
                     return { myProp: "test" };
                 };
             }
diff --git a/tests/baselines/reference/assignmentLHSIsValue.errors.txt b/tests/baselines/reference/assignmentLHSIsValue.errors.txt
index f97ae2bcfa5c1..a8772e7eec647 100644
--- a/tests/baselines/reference/assignmentLHSIsValue.errors.txt
+++ b/tests/baselines/reference/assignmentLHSIsValue.errors.txt
@@ -3,10 +3,10 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(8,21): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(11,18): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(13,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(17,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(19,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(22,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(24,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(17,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(19,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(22,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(24,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(27,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(28,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(29,1): error TS2364: Invalid left-hand side of assignment expression.
@@ -24,10 +24,10 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(5
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(51,11): error TS1005: ';' expected.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(54,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(57,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(58,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(59,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(60,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(61,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(58,2): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(59,2): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(60,2): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(61,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(62,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(63,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(64,1): error TS2364: Invalid left-hand side of assignment expression.
@@ -68,20 +68,20 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
     module M { export var a; }
     M = value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     C = value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     enum E { }
     E = value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     
     foo = value;
     ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     
     // literals
     null = value;
@@ -150,17 +150,17 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
     ~~~~~~
 !!! error TS2364: Invalid left-hand side of assignment expression.
     (M) = value;
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     (C) = value;
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     (E) = value;
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     (foo) = value;
-    ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~~~
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     (null) = value;
     ~~~~~~
 !!! error TS2364: Invalid left-hand side of assignment expression.
diff --git a/tests/baselines/reference/assignmentToFunction.errors.txt b/tests/baselines/reference/assignmentToFunction.errors.txt
index b9a2f1f267518..6e9b1b3c6ddbe 100644
--- a/tests/baselines/reference/assignmentToFunction.errors.txt
+++ b/tests/baselines/reference/assignmentToFunction.errors.txt
@@ -1,12 +1,12 @@
-tests/cases/compiler/assignmentToFunction.ts(2,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/compiler/assignmentToFunction.ts(8,9): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/assignmentToFunction.ts(2,1): error TS2539: Cannot assign to 'fn' because it is not a variable.
+tests/cases/compiler/assignmentToFunction.ts(8,9): error TS2539: Cannot assign to 'bar' because it is not a variable.
 
 
 ==== tests/cases/compiler/assignmentToFunction.ts (2 errors) ====
     function fn() { }
     fn = () => 3;
     ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'fn' because it is not a variable.
     
     module foo {
         function xyz() {
@@ -14,6 +14,6 @@ tests/cases/compiler/assignmentToFunction.ts(8,9): error TS2364: Invalid left-ha
             }
             bar = null;
             ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'bar' because it is not a variable.
         }
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/assignmentToParenthesizedIdentifiers.errors.txt b/tests/baselines/reference/assignmentToParenthesizedIdentifiers.errors.txt
index b929704880ecd..907fcce4c315b 100644
--- a/tests/baselines/reference/assignmentToParenthesizedIdentifiers.errors.txt
+++ b/tests/baselines/reference/assignmentToParenthesizedIdentifiers.errors.txt
@@ -3,9 +3,9 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(13,1): error TS2322: Type '""' is not assignable to type 'number'.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(14,1): error TS2322: Type '""' is not assignable to type 'number'.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(15,1): error TS2322: Type '""' is not assignable to type 'number'.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(17,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(18,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(25,5): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(17,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(18,2): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(25,5): error TS2539: Cannot assign to 'M3' because it is not a variable.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(31,1): error TS2322: Type '{ x: string; }' is not assignable to type 'typeof M3'.
   Types of property 'x' are incompatible.
     Type 'string' is not assignable to type 'number'.
@@ -15,8 +15,8 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(33,1): error TS2322: Type '{ x: string; }' is not assignable to type 'typeof M3'.
   Types of property 'x' are incompatible.
     Type 'string' is not assignable to type 'number'.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(37,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(38,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(37,1): error TS2539: Cannot assign to 'fn' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(38,2): error TS2539: Cannot assign to 'fn' because it is not a variable.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(43,5): error TS2322: Type '""' is not assignable to type 'number'.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(44,5): error TS2322: Type '""' is not assignable to type 'number'.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(48,5): error TS2322: Type '""' is not assignable to type 'number'.
@@ -24,10 +24,10 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(54,5): error TS2322: Type '""' is not assignable to type 'number'.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(55,5): error TS2322: Type '""' is not assignable to type 'number'.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(56,5): error TS2322: Type '""' is not assignable to type 'number'.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(62,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(63,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(69,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(70,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(62,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(63,2): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(69,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(70,2): error TS2539: Cannot assign to 'C' because it is not a variable.
 
 
 ==== tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts (24 errors) ====
@@ -59,10 +59,10 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
     
     M = { y: 3 }; // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     (M) = { y: 3 }; // Error
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     module M2 {
         export module M3 {
@@ -71,7 +71,7 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
     
         M3 = { x: 3 }; // Error
         ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M3' because it is not a variable.
     }
     M2.M3 = { x: 3 }; // OK
     (M2).M3 = { x: 3 }; // OK
@@ -97,10 +97,10 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
     function fn() { }
     fn = () => 3; // Bug 823548: Should be error (fn is not a reference)
     ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'fn' because it is not a variable.
     (fn) = () => 3; // Should be error
-    ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~~
+!!! error TS2539: Cannot assign to 'fn' because it is not a variable.
     
     function fn2(x: number, y: { t: number }) {
         x = 3;
@@ -140,10 +140,10 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
     }
     E = undefined; // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     (E) = undefined; // Error
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     
     class C {
     
@@ -151,8 +151,8 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
     
     C = undefined; // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     (C) = undefined; // Error
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/assignmentToReferenceTypes.errors.txt b/tests/baselines/reference/assignmentToReferenceTypes.errors.txt
index 56d6adc41499f..7e323479d57b1 100644
--- a/tests/baselines/reference/assignmentToReferenceTypes.errors.txt
+++ b/tests/baselines/reference/assignmentToReferenceTypes.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/compiler/assignmentToReferenceTypes.ts(5,1): error TS2304: Cannot find name 'M'.
-tests/cases/compiler/assignmentToReferenceTypes.ts(9,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/compiler/assignmentToReferenceTypes.ts(13,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/compiler/assignmentToReferenceTypes.ts(16,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/assignmentToReferenceTypes.ts(9,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/compiler/assignmentToReferenceTypes.ts(13,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/compiler/assignmentToReferenceTypes.ts(16,1): error TS2539: Cannot assign to 'f' because it is not a variable.
 
 
 ==== tests/cases/compiler/assignmentToReferenceTypes.ts (4 errors) ====
@@ -17,18 +17,18 @@ tests/cases/compiler/assignmentToReferenceTypes.ts(16,1): error TS2364: Invalid
     }
     C = null;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     enum E {
     }
     E = null;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     
     function f() { }
     f = null;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     
     var x = 1;
     x = null;
diff --git a/tests/baselines/reference/assignments.errors.txt b/tests/baselines/reference/assignments.errors.txt
index 2e637a6c720a0..f99a4fc330d53 100644
--- a/tests/baselines/reference/assignments.errors.txt
+++ b/tests/baselines/reference/assignments.errors.txt
@@ -1,8 +1,8 @@
 tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(11,1): error TS2304: Cannot find name 'M'.
-tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(14,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(17,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(14,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(17,1): error TS2539: Cannot assign to 'E' because it is not a variable.
 tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(18,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(21,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(21,1): error TS2539: Cannot assign to 'fn' because it is not a variable.
 tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(31,1): error TS2693: 'I' only refers to a type, but is being used as a value here.
 
 
@@ -24,12 +24,12 @@ tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(31,1): er
     class C { }
     C = null; // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     enum E { A }
     E = null; // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     E.A = null; // OK per spec, Error per implementation (509581)
     ~~~
 !!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
@@ -37,7 +37,7 @@ tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(31,1): er
     function fn() { }
     fn = null; // Should be error
     ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'fn' because it is not a variable.
     
     var v;
     v = null; // OK
diff --git a/tests/baselines/reference/compoundAssignmentLHSIsValue.errors.txt b/tests/baselines/reference/compoundAssignmentLHSIsValue.errors.txt
index 61f893ba88fa5..c4508c7e0b9a5 100644
--- a/tests/baselines/reference/compoundAssignmentLHSIsValue.errors.txt
+++ b/tests/baselines/reference/compoundAssignmentLHSIsValue.errors.txt
@@ -8,14 +8,14 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(23,5): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(26,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(27,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(31,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(32,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(34,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(35,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(38,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(39,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(41,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(42,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(31,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(32,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(34,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(35,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(38,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(39,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(41,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(42,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(45,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(46,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(47,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
@@ -46,14 +46,14 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(93,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(96,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(97,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(98,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(99,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(100,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(101,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(102,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(103,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(104,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(105,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(98,2): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(99,2): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(100,2): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(101,2): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(102,2): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(103,2): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(104,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(105,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(106,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(107,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(108,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
@@ -127,32 +127,32 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
     module M { export var a; }
     M *= value;
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     M += value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     C *= value;
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     C += value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     enum E { }
     E *= value;
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     E += value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     
     foo *= value;
     ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     foo += value;
     ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     
     // literals
     null *= value;
@@ -269,29 +269,29 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
     ~~~~~~
 !!! error TS2364: Invalid left-hand side of assignment expression.
     (M) *= value;
-    ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     (M) += value;
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     (C) *= value;
-    ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     (C) += value;
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     (E) *= value;
-    ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     (E) += value;
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     (foo) *= value;
-    ~~~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~~~
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     (foo) += value;
-    ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~~~
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     (null) *= value;
     ~~~~~~
 !!! error TS2364: Invalid left-hand side of assignment expression.
diff --git a/tests/baselines/reference/compoundExponentiationAssignmentLHSIsValue.errors.txt b/tests/baselines/reference/compoundExponentiationAssignmentLHSIsValue.errors.txt
index 0d9bab910ef88..0871f3944b66e 100644
--- a/tests/baselines/reference/compoundExponentiationAssignmentLHSIsValue.errors.txt
+++ b/tests/baselines/reference/compoundExponentiationAssignmentLHSIsValue.errors.txt
@@ -3,10 +3,10 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(13,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(18,5): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(21,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(25,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(27,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(30,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(32,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(25,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(27,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(30,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(32,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(35,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(36,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(37,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
@@ -23,10 +23,10 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(66,11): error TS1005: ';' expected.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(69,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(72,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(73,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(74,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(75,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(76,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(73,2): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(74,2): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(75,2): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(76,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(77,1): error TS2364: Invalid left-hand side of assignment expression.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(78,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(79,1): error TS2364: Invalid left-hand side of assignment expression.
@@ -75,20 +75,20 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
     module M { export var a; }
     M **= value;
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     C **= value;
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     enum E { }
     E **= value;
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     
     foo **= value;
     ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     
     // literals
     null **= value;
@@ -162,17 +162,17 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
     ~~~~~~
 !!! error TS2364: Invalid left-hand side of assignment expression.
     (M) **= value;
-    ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     (C) **= value;
-    ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     (E) **= value;
-    ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     (foo) **= value;
-    ~~~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~~~
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     (null) **= value;
     ~~~~~~
 !!! error TS2364: Invalid left-hand side of assignment expression.
diff --git a/tests/baselines/reference/concatClassAndString.errors.txt b/tests/baselines/reference/concatClassAndString.errors.txt
index 623c213181f9a..b0cb54b31c075 100644
--- a/tests/baselines/reference/concatClassAndString.errors.txt
+++ b/tests/baselines/reference/concatClassAndString.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/concatClassAndString.ts(4,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/concatClassAndString.ts(4,1): error TS2539: Cannot assign to 'f' because it is not a variable.
 
 
 ==== tests/cases/compiler/concatClassAndString.ts (1 errors) ====
@@ -7,5 +7,5 @@ tests/cases/compiler/concatClassAndString.ts(4,1): error TS2364: Invalid left-ha
     
     f += '';
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/constDeclarations-access.errors.txt b/tests/baselines/reference/constDeclarations-access.errors.txt
index 3c748cc4a5ff5..81121b6fe5ceb 100644
--- a/tests/baselines/reference/constDeclarations-access.errors.txt
+++ b/tests/baselines/reference/constDeclarations-access.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/file2.ts(1,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/file2.ts(1,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/file1.ts (0 errors) ====
@@ -8,4 +8,4 @@ tests/cases/compiler/file2.ts(1,1): error TS2449: The operand of an increment or
 ==== tests/cases/compiler/file2.ts (1 errors) ====
     x++;
     ~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
\ No newline at end of file
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
\ No newline at end of file
diff --git a/tests/baselines/reference/constDeclarations-access2.errors.txt b/tests/baselines/reference/constDeclarations-access2.errors.txt
index 667f490a374a1..16335bfa59cbe 100644
--- a/tests/baselines/reference/constDeclarations-access2.errors.txt
+++ b/tests/baselines/reference/constDeclarations-access2.errors.txt
@@ -1,20 +1,20 @@
-tests/cases/compiler/constDeclarations-access2.ts(5,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(6,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(7,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(9,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(10,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(11,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(12,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(13,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(14,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(15,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(16,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(18,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(19,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(20,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(21,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(23,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(5,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(6,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(7,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(8,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(9,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(10,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(11,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(12,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(13,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(14,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(15,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(16,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(18,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(19,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(20,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(21,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(23,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/constDeclarations-access2.ts (17 errors) ====
@@ -24,57 +24,57 @@ tests/cases/compiler/constDeclarations-access2.ts(23,3): error TS2449: The opera
     // Errors
     x = 1;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x += 2;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x -= 3;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x *= 4;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x /= 5;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x %= 6;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x <<= 7;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x >>= 8;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x >>>= 9;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x &= 10;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x |= 11;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x ^= 12;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     x++;
     ~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x--;
     ~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     ++x;
       ~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     --x;
       ~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     ++((x));
-      ~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     // OK
     var a = x + 1;
diff --git a/tests/baselines/reference/constDeclarations-errors.errors.txt b/tests/baselines/reference/constDeclarations-errors.errors.txt
index 2c9c17cc102f9..ace4cd7b25f27 100644
--- a/tests/baselines/reference/constDeclarations-errors.errors.txt
+++ b/tests/baselines/reference/constDeclarations-errors.errors.txt
@@ -5,7 +5,7 @@ tests/cases/compiler/constDeclarations-errors.ts(5,11): error TS1155: 'const' de
 tests/cases/compiler/constDeclarations-errors.ts(5,15): error TS1155: 'const' declarations must be initialized
 tests/cases/compiler/constDeclarations-errors.ts(5,27): error TS1155: 'const' declarations must be initialized
 tests/cases/compiler/constDeclarations-errors.ts(10,19): error TS2365: Operator '<' cannot be applied to types '0' and '1'.
-tests/cases/compiler/constDeclarations-errors.ts(10,27): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations-errors.ts(10,27): error TS2540: Cannot assign to 'c8' because it is a constant or a read-only property.
 tests/cases/compiler/constDeclarations-errors.ts(13,11): error TS1155: 'const' declarations must be initialized
 tests/cases/compiler/constDeclarations-errors.ts(16,20): error TS1155: 'const' declarations must be initialized
 tests/cases/compiler/constDeclarations-errors.ts(16,25): error TS2365: Operator '<' cannot be applied to types '0' and '1'.
@@ -37,7 +37,7 @@ tests/cases/compiler/constDeclarations-errors.ts(16,25): error TS2365: Operator
                       ~~~~~~
 !!! error TS2365: Operator '<' cannot be applied to types '0' and '1'.
                               ~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'c8' because it is a constant or a read-only property.
     
     // error, can not be unintalized
     for(const c9; c9 < 1;) { }
diff --git a/tests/baselines/reference/decrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt b/tests/baselines/reference/decrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt
index 2e1d594164d91..a796534af30e3 100644
--- a/tests/baselines/reference/decrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt
+++ b/tests/baselines/reference/decrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt
@@ -1,19 +1,19 @@
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(24,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(25,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(26,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(25,25): error TS2539: Cannot assign to 'A' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(26,25): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(27,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(28,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(30,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(31,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(32,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(31,23): error TS2539: Cannot assign to 'A' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(32,23): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(33,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(34,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(37,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(38,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(39,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(39,26): error TS2539: Cannot assign to 'undefined' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(41,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(42,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(43,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(43,24): error TS2539: Cannot assign to 'undefined' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(46,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(47,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
@@ -79,10 +79,10 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber2 = --A;
                             ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'A' because it is not a variable.
     var ResultIsNumber3 = --M;
                             ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     var ResultIsNumber4 = --obj;
                             ~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -95,10 +95,10 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber7 = A--;
                           ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'A' because it is not a variable.
     var ResultIsNumber8 = M--;
                           ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     var ResultIsNumber9 = obj--;
                           ~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -115,7 +115,7 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber13 = --undefined;
                              ~~~~~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'undefined' because it is not a variable.
     
     var ResultIsNumber14 = null--;
                            ~~~~
@@ -125,7 +125,7 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber16 = undefined--;
                            ~~~~~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'undefined' because it is not a variable.
     
     // any type expressions
     var ResultIsNumber17 = --foo();
diff --git a/tests/baselines/reference/decrementOperatorWithEnumTypeInvalidOperations.errors.txt b/tests/baselines/reference/decrementOperatorWithEnumTypeInvalidOperations.errors.txt
index 079bb2a6b640c..bd4223786a214 100644
--- a/tests/baselines/reference/decrementOperatorWithEnumTypeInvalidOperations.errors.txt
+++ b/tests/baselines/reference/decrementOperatorWithEnumTypeInvalidOperations.errors.txt
@@ -1,15 +1,15 @@
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(7,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(8,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(10,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(11,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(7,25): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(8,25): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(10,23): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(11,23): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(14,25): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(14,43): error TS2339: Property 'B' does not exist on type 'typeof ENUM'.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(15,23): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(15,29): error TS2339: Property 'A' does not exist on type 'typeof ENUM'.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(18,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(19,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(21,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(22,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(18,3): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(19,3): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(21,1): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(22,1): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
 
 
 ==== tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts (12 errors) ====
@@ -21,17 +21,17 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     // enum type var
     var ResultIsNumber1 = --ENUM;
                             ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     var ResultIsNumber2 = --ENUM1;
                             ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
     
     var ResultIsNumber3 = ENUM--;
                           ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     var ResultIsNumber4 = ENUM1--;
                           ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
     
     // enum type expressions
     var ResultIsNumber5 = --(ENUM["A"] + ENUM.B);
@@ -48,14 +48,14 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     // miss assignment operator
     --ENUM;
       ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     --ENUM1;
       ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
     
     ENUM--;
     ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     ENUM1--;
     ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
\ No newline at end of file
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
\ No newline at end of file
diff --git a/tests/baselines/reference/enumLiteralTypes1.types b/tests/baselines/reference/enumLiteralTypes1.types
index 754574f547cd2..b2a466c777de0 100644
--- a/tests/baselines/reference/enumLiteralTypes1.types
+++ b/tests/baselines/reference/enumLiteralTypes1.types
@@ -209,11 +209,11 @@ function f4(a: Choice.Yes, b: YesNo) {
 
     a++;
 >a++ : number
->a : Choice.Yes
+>a : Choice
 
     b++;
 >b++ : number
->b : YesNo
+>b : Choice
 }
 
 declare function g(x: Choice.Yes): string;
diff --git a/tests/baselines/reference/enumLiteralTypes2.types b/tests/baselines/reference/enumLiteralTypes2.types
index e27410a4dc710..6b881bee8c30c 100644
--- a/tests/baselines/reference/enumLiteralTypes2.types
+++ b/tests/baselines/reference/enumLiteralTypes2.types
@@ -210,7 +210,7 @@ function f4(a: Choice.Yes, b: UnknownYesNo) {
 
     a++;
 >a++ : number
->a : Choice.Yes
+>a : Choice
 
     b++;
 >b++ : number
diff --git a/tests/baselines/reference/for-of2.errors.txt b/tests/baselines/reference/for-of2.errors.txt
index f4f39f60f670b..1975f8be0afad 100644
--- a/tests/baselines/reference/for-of2.errors.txt
+++ b/tests/baselines/reference/for-of2.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/es6/for-ofStatements/for-of2.ts(1,7): error TS1155: 'const' declarations must be initialized
-tests/cases/conformance/es6/for-ofStatements/for-of2.ts(2,6): error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+tests/cases/conformance/es6/for-ofStatements/for-of2.ts(2,6): error TS2540: Cannot assign to 'v' because it is a constant or a read-only property.
 
 
 ==== tests/cases/conformance/es6/for-ofStatements/for-of2.ts (2 errors) ====
@@ -8,4 +8,4 @@ tests/cases/conformance/es6/for-ofStatements/for-of2.ts(2,6): error TS2485: The
 !!! error TS1155: 'const' declarations must be initialized
     for (v of []) { }
          ~
-!!! error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
\ No newline at end of file
+!!! error TS2540: Cannot assign to 'v' because it is a constant or a read-only property.
\ No newline at end of file
diff --git a/tests/baselines/reference/importsImplicitlyReadonly.errors.txt b/tests/baselines/reference/importsImplicitlyReadonly.errors.txt
index cc6e1918020e5..f0a781888fa3d 100644
--- a/tests/baselines/reference/importsImplicitlyReadonly.errors.txt
+++ b/tests/baselines/reference/importsImplicitlyReadonly.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/conformance/externalModules/b.ts(6,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/externalModules/b.ts(7,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/externalModules/b.ts(6,1): error TS2539: Cannot assign to 'x' because it is not a variable.
+tests/cases/conformance/externalModules/b.ts(7,1): error TS2539: Cannot assign to 'y' because it is not a variable.
 tests/cases/conformance/externalModules/b.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
 tests/cases/conformance/externalModules/b.ts(9,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
 
@@ -12,10 +12,10 @@ tests/cases/conformance/externalModules/b.ts(9,1): error TS2450: Left-hand side
     
     x = 1;     // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'x' because it is not a variable.
     y = 1;     // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'y' because it is not a variable.
     a1.x = 1;  // Error
     ~~~~
 !!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
diff --git a/tests/baselines/reference/incrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt b/tests/baselines/reference/incrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt
index 4aae7f5b51ea4..be17df7db927d 100644
--- a/tests/baselines/reference/incrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt
+++ b/tests/baselines/reference/incrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt
@@ -1,19 +1,19 @@
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(24,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(25,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(26,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(25,25): error TS2539: Cannot assign to 'A' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(26,25): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(27,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(28,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(30,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(31,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(32,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(31,23): error TS2539: Cannot assign to 'A' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(32,23): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(33,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(34,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(37,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(38,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(39,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(39,26): error TS2539: Cannot assign to 'undefined' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(41,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(42,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(43,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(43,24): error TS2539: Cannot assign to 'undefined' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(46,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(47,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
@@ -74,10 +74,10 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber2 = ++A;
                             ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'A' because it is not a variable.
     var ResultIsNumber3 = ++M;
                             ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     var ResultIsNumber4 = ++obj;
                             ~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -90,10 +90,10 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber7 = A++;
                           ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'A' because it is not a variable.
     var ResultIsNumber8 = M++;
                           ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     var ResultIsNumber9 = obj++;
                           ~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -110,7 +110,7 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber13 = ++undefined;
                              ~~~~~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'undefined' because it is not a variable.
     
     var ResultIsNumber14 = null++;
                            ~~~~
@@ -120,7 +120,7 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber16 = undefined++;
                            ~~~~~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'undefined' because it is not a variable.
     
     // any type expressions
     var ResultIsNumber17 = ++foo();
diff --git a/tests/baselines/reference/incrementOperatorWithEnumTypeInvalidOperations.errors.txt b/tests/baselines/reference/incrementOperatorWithEnumTypeInvalidOperations.errors.txt
index 08a1b8ec460ea..ac021746157a0 100644
--- a/tests/baselines/reference/incrementOperatorWithEnumTypeInvalidOperations.errors.txt
+++ b/tests/baselines/reference/incrementOperatorWithEnumTypeInvalidOperations.errors.txt
@@ -1,13 +1,13 @@
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(7,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(8,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(10,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(11,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(7,25): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(8,25): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(10,23): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(11,23): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(14,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(15,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(18,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(19,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(21,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(22,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(18,3): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(19,3): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(21,1): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(22,1): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
 
 
 ==== tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts (10 errors) ====
@@ -19,17 +19,17 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     // enum type var
     var ResultIsNumber1 = ++ENUM;
                             ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     var ResultIsNumber2 = ++ENUM1;
                             ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
     
     var ResultIsNumber3 = ENUM++;
                           ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     var ResultIsNumber4 = ENUM1++;
                           ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
     
     // enum type expressions
     var ResultIsNumber5 = ++(ENUM[1] + ENUM[2]);
@@ -42,14 +42,14 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     // miss assignment operator
     ++ENUM;
       ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     ++ENUM1;
       ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
     
     ENUM++;
     ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     ENUM1++;
     ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
\ No newline at end of file
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
\ No newline at end of file
diff --git a/tests/baselines/reference/invalidBooleanAssignments.errors.txt b/tests/baselines/reference/invalidBooleanAssignments.errors.txt
index 7963197a0037d..06ec14b4dd6eb 100644
--- a/tests/baselines/reference/invalidBooleanAssignments.errors.txt
+++ b/tests/baselines/reference/invalidBooleanAssignments.errors.txt
@@ -5,9 +5,9 @@ tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(9,
 tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(12,5): error TS2322: Type 'true' is not assignable to type 'C'.
 tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(15,5): error TS2322: Type 'true' is not assignable to type 'I'.
 tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(17,5): error TS2322: Type 'true' is not assignable to type '() => string'.
-tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(21,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(21,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(24,5): error TS2322: Type 'boolean' is not assignable to type 'T'.
-tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(26,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(26,1): error TS2539: Cannot assign to 'i' because it is not a variable.
 
 
 ==== tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts (10 errors) ====
@@ -47,7 +47,7 @@ tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(26
     module M { export var a = 1; }
     M = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     function i<T>(a: T) {
         a = x;
@@ -56,4 +56,4 @@ tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(26
     }
     i = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
\ No newline at end of file
+!!! error TS2539: Cannot assign to 'i' because it is not a variable.
\ No newline at end of file
diff --git a/tests/baselines/reference/invalidNumberAssignments.errors.txt b/tests/baselines/reference/invalidNumberAssignments.errors.txt
index 23f308830ff12..102376f1c501e 100644
--- a/tests/baselines/reference/invalidNumberAssignments.errors.txt
+++ b/tests/baselines/reference/invalidNumberAssignments.errors.txt
@@ -5,9 +5,9 @@ tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(9,5)
 tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(12,5): error TS2322: Type 'number' is not assignable to type 'I'.
 tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(14,5): error TS2322: Type '1' is not assignable to type '{ baz: string; }'.
 tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(15,5): error TS2322: Type '1' is not assignable to type '{ 0: number; }'.
-tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(18,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(18,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(21,5): error TS2322: Type 'number' is not assignable to type 'T'.
-tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(23,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(23,1): error TS2539: Cannot assign to 'i' because it is not a variable.
 
 
 ==== tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts (10 errors) ====
@@ -44,7 +44,7 @@ tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(23,1
     module M { export var x = 1; }
     M = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     function i<T>(a: T) {
         a = x;
@@ -53,4 +53,4 @@ tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(23,1
     }
     i = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
\ No newline at end of file
+!!! error TS2539: Cannot assign to 'i' because it is not a variable.
\ No newline at end of file
diff --git a/tests/baselines/reference/invalidStringAssignments.errors.txt b/tests/baselines/reference/invalidStringAssignments.errors.txt
index b37c56e8a40b6..728ce09e6b41e 100644
--- a/tests/baselines/reference/invalidStringAssignments.errors.txt
+++ b/tests/baselines/reference/invalidStringAssignments.errors.txt
@@ -5,9 +5,9 @@ tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(9,5)
 tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(12,5): error TS2322: Type 'string' is not assignable to type 'I'.
 tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(14,5): error TS2322: Type '1' is not assignable to type '{ baz: string; }'.
 tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(15,5): error TS2322: Type '1' is not assignable to type '{ 0: number; }'.
-tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(18,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(18,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(21,5): error TS2322: Type 'string' is not assignable to type 'T'.
-tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(23,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(23,1): error TS2539: Cannot assign to 'i' because it is not a variable.
 tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(26,5): error TS2322: Type 'string' is not assignable to type 'E'.
 
 
@@ -45,7 +45,7 @@ tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(26,5
     module M { export var x = 1; }
     M = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     function i<T>(a: T) {
         a = x;
@@ -54,7 +54,7 @@ tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(26,5
     }
     i = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'i' because it is not a variable.
     
     enum E { A }
     var j: E = x;
diff --git a/tests/baselines/reference/invalidUndefinedAssignments.errors.txt b/tests/baselines/reference/invalidUndefinedAssignments.errors.txt
index 05921e9433f52..2f34bafd98f8d 100644
--- a/tests/baselines/reference/invalidUndefinedAssignments.errors.txt
+++ b/tests/baselines/reference/invalidUndefinedAssignments.errors.txt
@@ -1,9 +1,9 @@
-tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(4,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(4,1): error TS2539: Cannot assign to 'E' because it is not a variable.
 tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(5,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(9,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(9,1): error TS2539: Cannot assign to 'C' because it is not a variable.
 tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(14,1): error TS2693: 'I' only refers to a type, but is being used as a value here.
-tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(17,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(21,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(17,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(21,1): error TS2539: Cannot assign to 'i' because it is not a variable.
 
 
 ==== tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts (6 errors) ====
@@ -12,7 +12,7 @@ tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.t
     enum E { A }
     E = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     E.A = x;
     ~~~
 !!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
@@ -21,7 +21,7 @@ tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.t
     var f: C;
     C = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     interface I { foo: string }
     var g: I;
@@ -33,10 +33,10 @@ tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.t
     module M { export var x = 1; }
     M = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     function i<T>(a: T) { }
     // BUG 767030
     i = x; 
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
\ No newline at end of file
+!!! error TS2539: Cannot assign to 'i' because it is not a variable.
\ No newline at end of file
diff --git a/tests/baselines/reference/invalidVoidAssignments.errors.txt b/tests/baselines/reference/invalidVoidAssignments.errors.txt
index de19fc3a21874..ae599fb52b0be 100644
--- a/tests/baselines/reference/invalidVoidAssignments.errors.txt
+++ b/tests/baselines/reference/invalidVoidAssignments.errors.txt
@@ -5,9 +5,9 @@ tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(9,5): er
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(12,5): error TS2322: Type 'void' is not assignable to type 'I'.
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(14,5): error TS2322: Type '1' is not assignable to type '{ baz: string; }'.
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(15,5): error TS2322: Type '1' is not assignable to type '{ 0: number; }'.
-tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(18,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(18,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(21,5): error TS2322: Type 'void' is not assignable to type 'T'.
-tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(23,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(23,1): error TS2539: Cannot assign to 'i' because it is not a variable.
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(26,1): error TS2322: Type 'typeof E' is not assignable to type 'void'.
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(27,1): error TS2322: Type 'E' is not assignable to type 'void'.
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(29,1): error TS2322: Type '{ f(): void; }' is not assignable to type 'void'.
@@ -47,7 +47,7 @@ tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(29,1): e
     module M { export var x = 1; }
     M = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     function i<T>(a: T) {
         a = x;
@@ -56,7 +56,7 @@ tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(29,1): e
     }
     i = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'i' because it is not a variable.
     
     enum E { A }
     x = E;
diff --git a/tests/baselines/reference/nullAssignedToUndefined.errors.txt b/tests/baselines/reference/nullAssignedToUndefined.errors.txt
index 5f9921b58097b..88bd04a1e628e 100644
--- a/tests/baselines/reference/nullAssignedToUndefined.errors.txt
+++ b/tests/baselines/reference/nullAssignedToUndefined.errors.txt
@@ -1,8 +1,8 @@
-tests/cases/conformance/types/typeRelationships/assignmentCompatibility/nullAssignedToUndefined.ts(1,9): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/typeRelationships/assignmentCompatibility/nullAssignedToUndefined.ts(1,9): error TS2539: Cannot assign to 'undefined' because it is not a variable.
 
 
 ==== tests/cases/conformance/types/typeRelationships/assignmentCompatibility/nullAssignedToUndefined.ts (1 errors) ====
     var x = undefined = null; // error
             ~~~~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'undefined' because it is not a variable.
     var y: typeof undefined = null; // ok, widened
\ No newline at end of file
diff --git a/tests/baselines/reference/numericLiteralTypes1.types b/tests/baselines/reference/numericLiteralTypes1.types
index 56e4bcc0f3fc1..49c521ad15f35 100644
--- a/tests/baselines/reference/numericLiteralTypes1.types
+++ b/tests/baselines/reference/numericLiteralTypes1.types
@@ -202,11 +202,11 @@ function f4(a: 1, b: 0 | 1 | 2) {
 
     a++;
 >a++ : number
->a : 1
+>a : number
 
     b++;
 >b++ : number
->b : 0 | 1 | 2
+>b : number
 }
 
 declare function g(x: 0): string;
diff --git a/tests/baselines/reference/numericLiteralTypes2.types b/tests/baselines/reference/numericLiteralTypes2.types
index b8e2526a221fc..4c67154ad411b 100644
--- a/tests/baselines/reference/numericLiteralTypes2.types
+++ b/tests/baselines/reference/numericLiteralTypes2.types
@@ -203,11 +203,11 @@ function f4(a: 1, b: 0 | 1 | 2) {
 
     a++;
 >a++ : number
->a : 1
+>a : number
 
     b++;
 >b++ : number
->b : 0 | 1 | 2
+>b : number
 }
 
 declare function g(x: 0): string;
diff --git a/tests/baselines/reference/parserStrictMode3-negative.errors.txt b/tests/baselines/reference/parserStrictMode3-negative.errors.txt
index 464f6859de6dd..4ea779d5fdc19 100644
--- a/tests/baselines/reference/parserStrictMode3-negative.errors.txt
+++ b/tests/baselines/reference/parserStrictMode3-negative.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode3-negative.ts(1,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode3-negative.ts(1,1): error TS2539: Cannot assign to 'eval' because it is not a variable.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode3-negative.ts (1 errors) ====
     eval = 1;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
\ No newline at end of file
+!!! error TS2539: Cannot assign to 'eval' because it is not a variable.
\ No newline at end of file
diff --git a/tests/baselines/reference/parserStrictMode3.errors.txt b/tests/baselines/reference/parserStrictMode3.errors.txt
index b8f1e0f54b8df..688aa6e462bce 100644
--- a/tests/baselines/reference/parserStrictMode3.errors.txt
+++ b/tests/baselines/reference/parserStrictMode3.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode3.ts(2,1): error TS1100: Invalid use of 'eval' in strict mode.
-tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode3.ts(2,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode3.ts(2,1): error TS2539: Cannot assign to 'eval' because it is not a variable.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode3.ts (2 errors) ====
@@ -8,4 +8,4 @@ tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode3.ts(2,1):
     ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
\ No newline at end of file
+!!! error TS2539: Cannot assign to 'eval' because it is not a variable.
\ No newline at end of file
diff --git a/tests/baselines/reference/parserStrictMode5.errors.txt b/tests/baselines/reference/parserStrictMode5.errors.txt
index e541963a1fb5f..d3b0ab3f44a8c 100644
--- a/tests/baselines/reference/parserStrictMode5.errors.txt
+++ b/tests/baselines/reference/parserStrictMode5.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode5.ts(2,1): error TS1100: Invalid use of 'eval' in strict mode.
-tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode5.ts(2,1): error TS2365: Operator '+=' cannot be applied to types '(x: string) => any' and '1'.
+tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode5.ts(2,1): error TS2539: Cannot assign to 'eval' because it is not a variable.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode5.ts (2 errors) ====
@@ -7,5 +7,5 @@ tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode5.ts(2,1):
     eval += 1;
     ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
-    ~~~~~~~~~
-!!! error TS2365: Operator '+=' cannot be applied to types '(x: string) => any' and '1'.
\ No newline at end of file
+    ~~~~
+!!! error TS2539: Cannot assign to 'eval' because it is not a variable.
\ No newline at end of file
diff --git a/tests/baselines/reference/parserStrictMode6-negative.errors.txt b/tests/baselines/reference/parserStrictMode6-negative.errors.txt
index 69d7d1317299f..df373be0301f0 100644
--- a/tests/baselines/reference/parserStrictMode6-negative.errors.txt
+++ b/tests/baselines/reference/parserStrictMode6-negative.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode6-negative.ts(1,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode6-negative.ts(1,1): error TS2539: Cannot assign to 'eval' because it is not a variable.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode6-negative.ts (1 errors) ====
     eval++;
     ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
\ No newline at end of file
+!!! error TS2539: Cannot assign to 'eval' because it is not a variable.
\ No newline at end of file
diff --git a/tests/baselines/reference/parserStrictMode6.errors.txt b/tests/baselines/reference/parserStrictMode6.errors.txt
index 7ac0e7fdb4d17..2a8fda7f62f8f 100644
--- a/tests/baselines/reference/parserStrictMode6.errors.txt
+++ b/tests/baselines/reference/parserStrictMode6.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode6.ts(2,1): error TS1100: Invalid use of 'eval' in strict mode.
-tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode6.ts(2,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode6.ts(2,1): error TS2539: Cannot assign to 'eval' because it is not a variable.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode6.ts (2 errors) ====
@@ -8,4 +8,4 @@ tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode6.ts(2,1):
     ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
     ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
\ No newline at end of file
+!!! error TS2539: Cannot assign to 'eval' because it is not a variable.
\ No newline at end of file
diff --git a/tests/baselines/reference/parserStrictMode7.errors.txt b/tests/baselines/reference/parserStrictMode7.errors.txt
index 6ee6ca4304292..b4ea09f14d429 100644
--- a/tests/baselines/reference/parserStrictMode7.errors.txt
+++ b/tests/baselines/reference/parserStrictMode7.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode7.ts(2,3): error TS1100: Invalid use of 'eval' in strict mode.
-tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode7.ts(2,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode7.ts(2,3): error TS2539: Cannot assign to 'eval' because it is not a variable.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode7.ts (2 errors) ====
@@ -8,4 +8,4 @@ tests/cases/conformance/parser/ecmascript5/StrictMode/parserStrictMode7.ts(2,3):
       ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
       ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
\ No newline at end of file
+!!! error TS2539: Cannot assign to 'eval' because it is not a variable.
\ No newline at end of file
diff --git a/tests/baselines/reference/redefineArray.errors.txt b/tests/baselines/reference/redefineArray.errors.txt
index 82ef91807c28b..6a9cf95479891 100644
--- a/tests/baselines/reference/redefineArray.errors.txt
+++ b/tests/baselines/reference/redefineArray.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/compiler/redefineArray.ts(1,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/redefineArray.ts(1,1): error TS2540: Cannot assign to 'Array' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/redefineArray.ts (1 errors) ====
     Array = function (n:number, s:string) {return n;};
     ~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
\ No newline at end of file
+!!! error TS2540: Cannot assign to 'Array' because it is a constant or a read-only property.
\ No newline at end of file
diff --git a/tests/baselines/reference/sourceMapValidationIfElse.types b/tests/baselines/reference/sourceMapValidationIfElse.types
index 87103b792e7c1..b4a76d5564738 100644
--- a/tests/baselines/reference/sourceMapValidationIfElse.types
+++ b/tests/baselines/reference/sourceMapValidationIfElse.types
@@ -10,7 +10,7 @@ if (i == 10) {
 
     i++;
 >i++ : number
->i : 10
+>i : number
 
 } else
 {
@@ -22,7 +22,7 @@ if (i == 10)
 {
     i++;
 >i++ : number
->i : 10
+>i : number
 }
 else if (i == 20) {
 >i == 20 : boolean
@@ -31,7 +31,7 @@ else if (i == 20) {
 
     i--;
 >i-- : number
->i : 20
+>i : number
 
 } else if (i == 30) {
 >i == 30 : boolean
diff --git a/tests/baselines/reference/sourceMapValidationSwitch.types b/tests/baselines/reference/sourceMapValidationSwitch.types
index 359cabbfabe56..9df86ee213251 100644
--- a/tests/baselines/reference/sourceMapValidationSwitch.types
+++ b/tests/baselines/reference/sourceMapValidationSwitch.types
@@ -11,7 +11,7 @@ switch (x) {
 
         x++;
 >x++ : number
->x : 5
+>x : number
 
         break;
     case 10:
@@ -19,7 +19,7 @@ switch (x) {
         {
             x--;
 >x-- : number
->x : 10
+>x : number
 
             break;
         }
@@ -39,7 +39,7 @@ switch (x)
 
         x++;
 >x++ : number
->x : 5
+>x : number
 
         break;
     case 10:
@@ -47,7 +47,7 @@ switch (x)
         {
             x--;
 >x-- : number
->x : 10
+>x : number
 
             break;
         }
diff --git a/tests/baselines/reference/sourceMapValidationWhile.types b/tests/baselines/reference/sourceMapValidationWhile.types
index 8769d98ef256c..71b50d86736cc 100644
--- a/tests/baselines/reference/sourceMapValidationWhile.types
+++ b/tests/baselines/reference/sourceMapValidationWhile.types
@@ -10,7 +10,7 @@ while (a == 10) {
 
     a++;
 >a++ : number
->a : 10
+>a : number
 }
 while (a == 10)
 >a == 10 : boolean
@@ -19,5 +19,5 @@ while (a == 10)
 {
     a++;
 >a++ : number
->a : 10
+>a : number
 }
diff --git a/tests/baselines/reference/unaryOperatorsInStrictMode.errors.txt b/tests/baselines/reference/unaryOperatorsInStrictMode.errors.txt
index 53263e7c2e179..35963c058795b 100644
--- a/tests/baselines/reference/unaryOperatorsInStrictMode.errors.txt
+++ b/tests/baselines/reference/unaryOperatorsInStrictMode.errors.txt
@@ -1,15 +1,15 @@
 tests/cases/compiler/unaryOperatorsInStrictMode.ts(3,3): error TS1100: Invalid use of 'eval' in strict mode.
-tests/cases/compiler/unaryOperatorsInStrictMode.ts(3,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/compiler/unaryOperatorsInStrictMode.ts(3,3): error TS2539: Cannot assign to 'eval' because it is not a variable.
 tests/cases/compiler/unaryOperatorsInStrictMode.ts(4,3): error TS1100: Invalid use of 'eval' in strict mode.
-tests/cases/compiler/unaryOperatorsInStrictMode.ts(4,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/compiler/unaryOperatorsInStrictMode.ts(4,3): error TS2539: Cannot assign to 'eval' because it is not a variable.
 tests/cases/compiler/unaryOperatorsInStrictMode.ts(5,3): error TS1100: Invalid use of 'arguments' in strict mode.
 tests/cases/compiler/unaryOperatorsInStrictMode.ts(5,3): error TS2304: Cannot find name 'arguments'.
 tests/cases/compiler/unaryOperatorsInStrictMode.ts(6,3): error TS1100: Invalid use of 'arguments' in strict mode.
 tests/cases/compiler/unaryOperatorsInStrictMode.ts(6,3): error TS2304: Cannot find name 'arguments'.
 tests/cases/compiler/unaryOperatorsInStrictMode.ts(7,1): error TS1100: Invalid use of 'eval' in strict mode.
-tests/cases/compiler/unaryOperatorsInStrictMode.ts(7,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/compiler/unaryOperatorsInStrictMode.ts(7,1): error TS2539: Cannot assign to 'eval' because it is not a variable.
 tests/cases/compiler/unaryOperatorsInStrictMode.ts(8,1): error TS1100: Invalid use of 'eval' in strict mode.
-tests/cases/compiler/unaryOperatorsInStrictMode.ts(8,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/compiler/unaryOperatorsInStrictMode.ts(8,1): error TS2539: Cannot assign to 'eval' because it is not a variable.
 tests/cases/compiler/unaryOperatorsInStrictMode.ts(9,1): error TS1100: Invalid use of 'arguments' in strict mode.
 tests/cases/compiler/unaryOperatorsInStrictMode.ts(9,1): error TS2304: Cannot find name 'arguments'.
 tests/cases/compiler/unaryOperatorsInStrictMode.ts(10,1): error TS1100: Invalid use of 'arguments' in strict mode.
@@ -23,12 +23,12 @@ tests/cases/compiler/unaryOperatorsInStrictMode.ts(10,1): error TS2304: Cannot f
       ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
       ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'eval' because it is not a variable.
     --eval;
       ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
       ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'eval' because it is not a variable.
     ++arguments;
       ~~~~~~~~~
 !!! error TS1100: Invalid use of 'arguments' in strict mode.
@@ -43,12 +43,12 @@ tests/cases/compiler/unaryOperatorsInStrictMode.ts(10,1): error TS2304: Cannot f
     ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
     ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'eval' because it is not a variable.
     eval--;
     ~~~~
 !!! error TS1100: Invalid use of 'eval' in strict mode.
     ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'eval' because it is not a variable.
     arguments++;
     ~~~~~~~~~
 !!! error TS1100: Invalid use of 'arguments' in strict mode.
diff --git a/tests/baselines/reference/validNullAssignments.errors.txt b/tests/baselines/reference/validNullAssignments.errors.txt
index 1fcebdcbaa9a1..4ae9522d02357 100644
--- a/tests/baselines/reference/validNullAssignments.errors.txt
+++ b/tests/baselines/reference/validNullAssignments.errors.txt
@@ -1,8 +1,8 @@
 tests/cases/conformance/types/primitives/null/validNullAssignments.ts(10,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/primitives/null/validNullAssignments.ts(15,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/null/validNullAssignments.ts(15,1): error TS2539: Cannot assign to 'C' because it is not a variable.
 tests/cases/conformance/types/primitives/null/validNullAssignments.ts(20,1): error TS2693: 'I' only refers to a type, but is being used as a value here.
-tests/cases/conformance/types/primitives/null/validNullAssignments.ts(23,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/types/primitives/null/validNullAssignments.ts(30,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/null/validNullAssignments.ts(23,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/types/primitives/null/validNullAssignments.ts(30,1): error TS2539: Cannot assign to 'i' because it is not a variable.
 
 
 ==== tests/cases/conformance/types/primitives/null/validNullAssignments.ts (5 errors) ====
@@ -24,7 +24,7 @@ tests/cases/conformance/types/primitives/null/validNullAssignments.ts(30,1): err
     f = null; // ok
     C = null; // error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     interface I { foo: string }
     var g: I;
@@ -36,7 +36,7 @@ tests/cases/conformance/types/primitives/null/validNullAssignments.ts(30,1): err
     module M { export var x = 1; }
     M = null; // error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     var h: { f(): void } = null;
     
@@ -45,4 +45,4 @@ tests/cases/conformance/types/primitives/null/validNullAssignments.ts(30,1): err
     }
     i = null; // error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
\ No newline at end of file
+!!! error TS2539: Cannot assign to 'i' because it is not a variable.
\ No newline at end of file

From 6c205330a1079c96a473254f6b83da4a5020acd7 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sun, 30 Oct 2016 18:08:43 -0700
Subject: [PATCH 124/224] Improved error messages for invalid assignments to
 properties

---
 src/compiler/checker.ts   | 15 ++++++++++++---
 src/compiler/utilities.ts |  6 +++++-
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 5e23f56b947fa..bf3a4b94d0cc7 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -11459,16 +11459,25 @@ namespace ts {
             }
 
             const propType = getTypeOfSymbol(prop);
+            const assignmentKind = getAssignmentTargetKind(node);
+
+            if (assignmentKind) {
+                if (isReferenceToReadonlyEntity(<Expression>node, prop) || isReferenceThroughNamespaceImport(<Expression>node)) {
+                    error(right, Diagnostics.Cannot_assign_to_0_because_it_is_a_constant_or_a_read_only_property, right.text);
+                    return unknownType;
+                }
+            }
 
             // Only compute control flow type if this is a property access expression that isn't an
             // assignment target, and the referenced property was declared as a variable, property,
             // accessor, or optional method.
-            if (node.kind !== SyntaxKind.PropertyAccessExpression || isAssignmentTarget(node) ||
+            if (node.kind !== SyntaxKind.PropertyAccessExpression || assignmentKind === AssignmentKind.Definite ||
                 !(prop.flags & (SymbolFlags.Variable | SymbolFlags.Property | SymbolFlags.Accessor)) &&
                 !(prop.flags & SymbolFlags.Method && propType.flags & TypeFlags.Union)) {
                 return propType;
             }
-            return getFlowTypeOfReference(node, propType, /*assumeInitialized*/ true, /*flowContainer*/ undefined);
+            const flowType = getFlowTypeOfReference(node, propType, /*assumeInitialized*/ true, /*flowContainer*/ undefined);
+            return assignmentKind ? getBaseTypeOfLiteralType(flowType) : flowType;
         }
 
         function isValidPropertyAccess(node: PropertyAccessExpression | QualifiedName, propertyName: string): boolean {
@@ -13515,7 +13524,7 @@ namespace ts {
                 error(expr, invalidReferenceMessage);
                 return false;
             }
-            if (node.kind === SyntaxKind.Identifier) {
+            if (node.kind === SyntaxKind.Identifier || node.kind === SyntaxKind.PropertyAccessExpression) {
                 return true;
             }
             // Because we get the symbol from the resolvedSymbol property, it might be of kind
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index f9fe30b4e534c..e2e401cfae4f4 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -1649,8 +1649,12 @@ namespace ts {
                 case SyntaxKind.SpreadElementExpression:
                     node = parent;
                     break;
-                case SyntaxKind.PropertyAssignment:
                 case SyntaxKind.ShorthandPropertyAssignment:
+                    if ((<ShorthandPropertyAssignment>parent).name !== node) {
+                        return AssignmentKind.None;
+                    }
+                    // Fall through
+                case SyntaxKind.PropertyAssignment:
                     node = parent.parent;
                     break;
                 default:

From 88961cd164ff3c68383ebc1aad0b2c8f4b642b71 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sun, 30 Oct 2016 18:09:07 -0700
Subject: [PATCH 125/224] Accept new baselines

---
 .../abstractPropertyNegative.errors.txt       |   6 +-
 .../reference/assignToEnum.errors.txt         |  12 +--
 .../reference/assignments.errors.txt          |   6 +-
 .../constDeclarations-access3.errors.txt      | 102 +++++++++---------
 .../constDeclarations-access4.errors.txt      | 102 +++++++++---------
 .../constDeclarations-access5.errors.txt      | 102 +++++++++---------
 .../constEnumPropertyAccess2.errors.txt       |   6 +-
 .../decrementOperatorWithEnumType.errors.txt  |   6 +-
 ...externalModuleImmutableBindings.errors.txt |  48 ++++-----
 .../importsImplicitlyReadonly.errors.txt      |  12 +--
 .../incrementOperatorWithEnumType.errors.txt  |  12 +--
 .../intersectionTypeReadonly.errors.txt       |  30 +++---
 .../invalidUndefinedAssignments.errors.txt    |   6 +-
 .../readonlyConstructorAssignment.errors.txt  |   6 +-
 ...readonlyInConstructorParameters.errors.txt |   6 +-
 .../reference/readonlyMembers.errors.txt      |  78 +++++++-------
 .../reference/unionTypeReadonly.errors.txt    |  24 ++---
 .../reference/validNullAssignments.errors.txt |   6 +-
 18 files changed, 285 insertions(+), 285 deletions(-)

diff --git a/tests/baselines/reference/abstractPropertyNegative.errors.txt b/tests/baselines/reference/abstractPropertyNegative.errors.txt
index 448fb2255e0bb..314ab842ded14 100644
--- a/tests/baselines/reference/abstractPropertyNegative.errors.txt
+++ b/tests/baselines/reference/abstractPropertyNegative.errors.txt
@@ -6,7 +6,7 @@ tests/cases/compiler/abstractPropertyNegative.ts(13,7): error TS2515: Non-abstra
 tests/cases/compiler/abstractPropertyNegative.ts(13,7): error TS2515: Non-abstract class 'C' does not implement inherited abstract member 'readonlyProp' from class 'B'.
 tests/cases/compiler/abstractPropertyNegative.ts(15,5): error TS1244: Abstract methods can only appear within an abstract class.
 tests/cases/compiler/abstractPropertyNegative.ts(16,37): error TS1005: '{' expected.
-tests/cases/compiler/abstractPropertyNegative.ts(19,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/abstractPropertyNegative.ts(19,3): error TS2540: Cannot assign to 'ro' because it is a constant or a read-only property.
 tests/cases/compiler/abstractPropertyNegative.ts(24,7): error TS2415: Class 'WrongTypePropertyImpl' incorrectly extends base class 'WrongTypeProperty'.
   Types of property 'num' are incompatible.
     Type 'string' is not assignable to type 'number'.
@@ -58,8 +58,8 @@ tests/cases/compiler/abstractPropertyNegative.ts(41,18): error TS2676: Accessors
     }
     let c = new C();
     c.ro = "error: lhs of assignment can't be readonly";
-    ~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~~
+!!! error TS2540: Cannot assign to 'ro' because it is a constant or a read-only property.
     
     abstract class WrongTypeProperty {
         abstract num: number;
diff --git a/tests/baselines/reference/assignToEnum.errors.txt b/tests/baselines/reference/assignToEnum.errors.txt
index c907db7a8bfbf..438a002ef1ee9 100644
--- a/tests/baselines/reference/assignToEnum.errors.txt
+++ b/tests/baselines/reference/assignToEnum.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/compiler/assignToEnum.ts(2,1): error TS2539: Cannot assign to 'A' because it is not a variable.
 tests/cases/compiler/assignToEnum.ts(3,1): error TS2539: Cannot assign to 'A' because it is not a variable.
-tests/cases/compiler/assignToEnum.ts(4,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/assignToEnum.ts(5,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/assignToEnum.ts(4,3): error TS2540: Cannot assign to 'foo' because it is a constant or a read-only property.
+tests/cases/compiler/assignToEnum.ts(5,3): error TS2540: Cannot assign to 'foo' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/assignToEnum.ts (4 errors) ====
@@ -13,10 +13,10 @@ tests/cases/compiler/assignToEnum.ts(5,1): error TS2450: Left-hand side of assig
     ~
 !!! error TS2539: Cannot assign to 'A' because it is not a variable.
     A.foo = 1;      // invalid LHS
-    ~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~~~
+!!! error TS2540: Cannot assign to 'foo' because it is a constant or a read-only property.
     A.foo = A.bar;  // invalid LHS
-    ~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~~~
+!!! error TS2540: Cannot assign to 'foo' because it is a constant or a read-only property.
     
     
\ No newline at end of file
diff --git a/tests/baselines/reference/assignments.errors.txt b/tests/baselines/reference/assignments.errors.txt
index f99a4fc330d53..86bbe75cd4b77 100644
--- a/tests/baselines/reference/assignments.errors.txt
+++ b/tests/baselines/reference/assignments.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(11,1): error TS2304: Cannot find name 'M'.
 tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(14,1): error TS2539: Cannot assign to 'C' because it is not a variable.
 tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(17,1): error TS2539: Cannot assign to 'E' because it is not a variable.
-tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(18,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(18,3): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
 tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(21,1): error TS2539: Cannot assign to 'fn' because it is not a variable.
 tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(31,1): error TS2693: 'I' only refers to a type, but is being used as a value here.
 
@@ -31,8 +31,8 @@ tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(31,1): er
     ~
 !!! error TS2539: Cannot assign to 'E' because it is not a variable.
     E.A = null; // OK per spec, Error per implementation (509581)
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     
     function fn() { }
     fn = null; // Should be error
diff --git a/tests/baselines/reference/constDeclarations-access3.errors.txt b/tests/baselines/reference/constDeclarations-access3.errors.txt
index a6cb124d28c57..43864d5274dfa 100644
--- a/tests/baselines/reference/constDeclarations-access3.errors.txt
+++ b/tests/baselines/reference/constDeclarations-access3.errors.txt
@@ -1,20 +1,20 @@
-tests/cases/compiler/constDeclarations-access3.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(9,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(10,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(11,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(12,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(13,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(14,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(15,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(16,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(17,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(18,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(19,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(21,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(22,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(23,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(24,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(26,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(8,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(9,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(10,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(11,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(12,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(13,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(14,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(15,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(16,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(17,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(18,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(19,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(21,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(22,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(23,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(24,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(26,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/constDeclarations-access3.ts(28,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
 
 
@@ -27,58 +27,58 @@ tests/cases/compiler/constDeclarations-access3.ts(28,1): error TS2450: Left-hand
     
     // Errors
     M.x = 1;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x += 2;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x -= 3;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x *= 4;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x /= 5;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x %= 6;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x <<= 7;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x >>= 8;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x >>>= 9;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x &= 10;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x |= 11;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x ^= 12;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     M.x++;
-    ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x--;
-    ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     ++M.x;
-      ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     --M.x;
-      ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     ++((M.x));
-      ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+          ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     M["x"] = 0;
     ~~~~~~
diff --git a/tests/baselines/reference/constDeclarations-access4.errors.txt b/tests/baselines/reference/constDeclarations-access4.errors.txt
index 3d7d4a704a81e..d9b63941c764d 100644
--- a/tests/baselines/reference/constDeclarations-access4.errors.txt
+++ b/tests/baselines/reference/constDeclarations-access4.errors.txt
@@ -1,20 +1,20 @@
-tests/cases/compiler/constDeclarations-access4.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(9,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(10,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(11,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(12,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(13,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(14,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(15,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(16,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(17,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(18,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(19,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(21,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(22,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(23,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(24,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(26,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(8,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(9,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(10,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(11,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(12,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(13,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(14,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(15,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(16,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(17,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(18,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(19,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(21,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(22,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(23,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(24,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(26,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/constDeclarations-access4.ts(28,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
 
 
@@ -27,58 +27,58 @@ tests/cases/compiler/constDeclarations-access4.ts(28,1): error TS2450: Left-hand
     
     // Errors
     M.x = 1;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x += 2;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x -= 3;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x *= 4;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x /= 5;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x %= 6;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x <<= 7;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x >>= 8;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x >>>= 9;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x &= 10;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x |= 11;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x ^= 12;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     M.x++;
-    ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x--;
-    ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     ++M.x;
-      ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     --M.x;
-      ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     ++((M.x));
-      ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+          ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     M["x"] = 0;
     ~~~~~~
diff --git a/tests/baselines/reference/constDeclarations-access5.errors.txt b/tests/baselines/reference/constDeclarations-access5.errors.txt
index 45160bbc7cede..72f28b992a988 100644
--- a/tests/baselines/reference/constDeclarations-access5.errors.txt
+++ b/tests/baselines/reference/constDeclarations-access5.errors.txt
@@ -1,20 +1,20 @@
-tests/cases/compiler/constDeclarations_access_2.ts(4,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(5,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(6,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(7,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(9,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(10,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(11,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(12,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(13,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(14,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(15,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(17,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(18,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(19,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(20,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(22,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(4,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(5,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(6,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(7,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(8,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(9,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(10,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(11,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(12,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(13,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(14,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(15,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(17,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(18,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(19,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(20,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(22,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/constDeclarations_access_2.ts(24,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
 
 
@@ -23,58 +23,58 @@ tests/cases/compiler/constDeclarations_access_2.ts(24,1): error TS2450: Left-han
     import m = require('constDeclarations_access_1');
     // Errors
     m.x = 1;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x += 2;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x -= 3;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x *= 4;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x /= 5;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x %= 6;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x <<= 7;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x >>= 8;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x >>>= 9;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x &= 10;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x |= 11;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x ^= 12;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m
     m.x++;
-    ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x--;
-    ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     ++m.x;
-      ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     --m.x;
-      ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     ++((m.x));
-      ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+          ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     m["x"] = 0;
     ~~~~~~
diff --git a/tests/baselines/reference/constEnumPropertyAccess2.errors.txt b/tests/baselines/reference/constEnumPropertyAccess2.errors.txt
index ef5dd331d327f..9f16059ff2fc2 100644
--- a/tests/baselines/reference/constEnumPropertyAccess2.errors.txt
+++ b/tests/baselines/reference/constEnumPropertyAccess2.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(14,9): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
 tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(15,12): error TS2476: A const enum member can only be accessed using a string literal.
 tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(17,1): error TS2322: Type '"string"' is not assignable to type 'G'.
-tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(19,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(19,3): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
 
 
 ==== tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts (4 errors) ====
@@ -30,6 +30,6 @@ tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(19,1): error TS24
 !!! error TS2322: Type '"string"' is not assignable to type 'G'.
     function foo(x: G) { }
     G.B = 3;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/decrementOperatorWithEnumType.errors.txt b/tests/baselines/reference/decrementOperatorWithEnumType.errors.txt
index 29e06bc6a4e54..bad8dacd85611 100644
--- a/tests/baselines/reference/decrementOperatorWithEnumType.errors.txt
+++ b/tests/baselines/reference/decrementOperatorWithEnumType.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(6,25): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(7,23): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(7,29): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(10,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(12,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(12,7): error TS2304: Cannot find name 'A'.
@@ -15,8 +15,8 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
                             ~~~~~~~~~~
 !!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
     var ResultIsNumber2 = ENUM1.A--;
-                          ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+                                ~
+!!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     
     // miss assignment operator
     --ENUM1["A"];
diff --git a/tests/baselines/reference/externalModuleImmutableBindings.errors.txt b/tests/baselines/reference/externalModuleImmutableBindings.errors.txt
index c8c61b2dc816b..7454868e361dc 100644
--- a/tests/baselines/reference/externalModuleImmutableBindings.errors.txt
+++ b/tests/baselines/reference/externalModuleImmutableBindings.errors.txt
@@ -1,21 +1,21 @@
-tests/cases/compiler/f2.ts(7,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(7,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
 tests/cases/compiler/f2.ts(9,7): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
-tests/cases/compiler/f2.ts(12,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(12,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(13,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/f2.ts(17,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(17,8): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(18,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
 tests/cases/compiler/f2.ts(19,8): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
-tests/cases/compiler/f2.ts(22,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(22,8): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(23,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/f2.ts(27,6): error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
-tests/cases/compiler/f2.ts(28,6): error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(27,12): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(28,12): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(29,6): error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
 tests/cases/compiler/f2.ts(30,6): error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
 tests/cases/compiler/f2.ts(31,12): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
 tests/cases/compiler/f2.ts(32,12): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
-tests/cases/compiler/f2.ts(36,6): error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
-tests/cases/compiler/f2.ts(37,6): error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(36,13): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(37,13): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(38,6): error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
 tests/cases/compiler/f2.ts(39,6): error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
 tests/cases/compiler/f2.ts(40,13): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
@@ -33,8 +33,8 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
     var n = 'baz';
     
     stuff.x = 0;
-    ~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+          ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     stuff['x'] = 1;
     ~~~~~~~~~~
 !!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
@@ -44,8 +44,8 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
     stuff[n] = 3;
     
     stuff.x++;
-    ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+          ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     stuff['x']++;
     ~~~~~~~~~~
 !!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
@@ -53,8 +53,8 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
     stuff[n]++;
     
     (stuff.x) = 0;
-    ~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+           ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     (stuff['x']) = 1;
     ~~~~~~~~~~~~
 !!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
@@ -64,8 +64,8 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
     (stuff[n]) = 3;
     
     (stuff.x)++;
-    ~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+           ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     (stuff['x'])++;
     ~~~~~~~~~~~~
 !!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
@@ -73,11 +73,11 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
     (stuff[n])++;
     
     for (stuff.x in []) {}
-         ~~~~~~~
-!!! error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
+               ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for (stuff.x of []) {}
-         ~~~~~~~
-!!! error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+               ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for (stuff['x'] in []) {}
          ~~~~~~~~~~
 !!! error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
@@ -94,11 +94,11 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
     for (stuff[n] of []) {}
     
     for ((stuff.x) in []) {}
-         ~~~~~~~~~
-!!! error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
+                ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for ((stuff.x) of []) {}
-         ~~~~~~~~~
-!!! error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+                ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for ((stuff['x']) in []) {}
          ~~~~~~~~~~~~
 !!! error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
diff --git a/tests/baselines/reference/importsImplicitlyReadonly.errors.txt b/tests/baselines/reference/importsImplicitlyReadonly.errors.txt
index f0a781888fa3d..43596ffcea32e 100644
--- a/tests/baselines/reference/importsImplicitlyReadonly.errors.txt
+++ b/tests/baselines/reference/importsImplicitlyReadonly.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/conformance/externalModules/b.ts(6,1): error TS2539: Cannot assign to 'x' because it is not a variable.
 tests/cases/conformance/externalModules/b.ts(7,1): error TS2539: Cannot assign to 'y' because it is not a variable.
-tests/cases/conformance/externalModules/b.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/externalModules/b.ts(9,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/externalModules/b.ts(8,4): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/conformance/externalModules/b.ts(9,4): error TS2540: Cannot assign to 'y' because it is a constant or a read-only property.
 
 
 ==== tests/cases/conformance/externalModules/b.ts (4 errors) ====
@@ -17,11 +17,11 @@ tests/cases/conformance/externalModules/b.ts(9,1): error TS2450: Left-hand side
     ~
 !!! error TS2539: Cannot assign to 'y' because it is not a variable.
     a1.x = 1;  // Error
-    ~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+       ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     a1.y = 1;  // Error
-    ~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+       ~
+!!! error TS2540: Cannot assign to 'y' because it is a constant or a read-only property.
     a2.x = 1;
     a2.y = 1;
     a3.x = 1;
diff --git a/tests/baselines/reference/incrementOperatorWithEnumType.errors.txt b/tests/baselines/reference/incrementOperatorWithEnumType.errors.txt
index fc8b682b59e86..5dc16bdc511fa 100644
--- a/tests/baselines/reference/incrementOperatorWithEnumType.errors.txt
+++ b/tests/baselines/reference/incrementOperatorWithEnumType.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(6,25): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(7,23): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(7,29): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(10,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(12,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(12,7): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
 
 
 ==== tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts (4 errors) ====
@@ -14,8 +14,8 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
                             ~~~~~~~~~~
 !!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
     var ResultIsNumber2 = ENUM1.B++;
-                          ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+                                ~
+!!! error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
     
     // miss assignment operator
     ++ENUM1["B"];
@@ -23,5 +23,5 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
 !!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
     
     ENUM1.B++;
-    ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
\ No newline at end of file
+          ~
+!!! error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
\ No newline at end of file
diff --git a/tests/baselines/reference/intersectionTypeReadonly.errors.txt b/tests/baselines/reference/intersectionTypeReadonly.errors.txt
index d9e22fd222329..88ca9cb3b0c1b 100644
--- a/tests/baselines/reference/intersectionTypeReadonly.errors.txt
+++ b/tests/baselines/reference/intersectionTypeReadonly.errors.txt
@@ -1,8 +1,8 @@
-tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(17,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(19,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(21,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(23,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(25,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(17,6): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
+tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(19,11): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
+tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(21,9): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
+tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(23,15): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
+tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(25,15): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
 
 
 ==== tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts (5 errors) ====
@@ -23,22 +23,22 @@ tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(25,1): er
     }
     let base: Base;
     base.value = 12 // error, lhs can't be a readonly property
-    ~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+         ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     let identical: Base & Identical;
     identical.value = 12; // error, lhs can't be a readonly property
-    ~~~~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+              ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     let mutable: Base & Mutable;
     mutable.value = 12; // error, lhs can't be a readonly property
-    ~~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+            ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     let differentType: Base & DifferentType;
     differentType.value = 12; // error, lhs can't be a readonly property
-    ~~~~~~~~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                  ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     let differentName: Base & DifferentName;
     differentName.value = 12; // error, property 'value' doesn't exist
-    ~~~~~~~~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                  ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/invalidUndefinedAssignments.errors.txt b/tests/baselines/reference/invalidUndefinedAssignments.errors.txt
index 2f34bafd98f8d..b0a30f2dff3a9 100644
--- a/tests/baselines/reference/invalidUndefinedAssignments.errors.txt
+++ b/tests/baselines/reference/invalidUndefinedAssignments.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(4,1): error TS2539: Cannot assign to 'E' because it is not a variable.
-tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(5,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(5,3): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
 tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(9,1): error TS2539: Cannot assign to 'C' because it is not a variable.
 tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(14,1): error TS2693: 'I' only refers to a type, but is being used as a value here.
 tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(17,1): error TS2539: Cannot assign to 'M' because it is not a variable.
@@ -14,8 +14,8 @@ tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.t
     ~
 !!! error TS2539: Cannot assign to 'E' because it is not a variable.
     E.A = x;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     
     class C { foo: string }
     var f: C;
diff --git a/tests/baselines/reference/readonlyConstructorAssignment.errors.txt b/tests/baselines/reference/readonlyConstructorAssignment.errors.txt
index e764fe21edaeb..31b4ad969cb91 100644
--- a/tests/baselines/reference/readonlyConstructorAssignment.errors.txt
+++ b/tests/baselines/reference/readonlyConstructorAssignment.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/classes/constructorDeclarations/constructorParameters/readonlyConstructorAssignment.ts(13,9): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/readonlyConstructorAssignment.ts(13,14): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/conformance/classes/constructorDeclarations/constructorParameters/readonlyConstructorAssignment.ts(33,7): error TS2415: Class 'E' incorrectly extends base class 'D'.
   Property 'x' is private in type 'D' but not in type 'E'.
 
@@ -17,8 +17,8 @@ tests/cases/conformance/classes/constructorDeclarations/constructorParameters/re
             super(x);
             // Fails, x is readonly
             this.x = 1;
-            ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                 ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
         }
     }
     
diff --git a/tests/baselines/reference/readonlyInConstructorParameters.errors.txt b/tests/baselines/reference/readonlyInConstructorParameters.errors.txt
index 6e4b549ce74ec..15d0d0be8eb32 100644
--- a/tests/baselines/reference/readonlyInConstructorParameters.errors.txt
+++ b/tests/baselines/reference/readonlyInConstructorParameters.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/classes/constructorDeclarations/constructorParameters/readonlyInConstructorParameters.ts(4,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/classes/constructorDeclarations/constructorParameters/readonlyInConstructorParameters.ts(4,10): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/conformance/classes/constructorDeclarations/constructorParameters/readonlyInConstructorParameters.ts(7,26): error TS1029: 'public' modifier must precede 'readonly' modifier.
 tests/cases/conformance/classes/constructorDeclarations/constructorParameters/readonlyInConstructorParameters.ts(13,10): error TS2341: Property 'x' is private and only accessible within class 'F'.
 
@@ -8,8 +8,8 @@ tests/cases/conformance/classes/constructorDeclarations/constructorParameters/re
         constructor(readonly x: number) {}
     }
     new C(1).x = 2;
-    ~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+             ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     class E {
         constructor(readonly public x: number) {}
diff --git a/tests/baselines/reference/readonlyMembers.errors.txt b/tests/baselines/reference/readonlyMembers.errors.txt
index 7bc10aa374690..bea3a81bf7c99 100644
--- a/tests/baselines/reference/readonlyMembers.errors.txt
+++ b/tests/baselines/reference/readonlyMembers.errors.txt
@@ -1,16 +1,16 @@
-tests/cases/compiler/readonlyMembers.ts(7,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(17,9): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(19,13): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(20,13): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(21,13): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(25,9): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(26,9): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(27,9): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(36,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(40,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(49,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(56,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(7,3): error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(8,3): error TS2540: Cannot assign to 'b' because it is a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(17,14): error TS2540: Cannot assign to 'c' because it is a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(19,18): error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(20,18): error TS2540: Cannot assign to 'b' because it is a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(21,18): error TS2540: Cannot assign to 'c' because it is a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(25,14): error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(26,14): error TS2540: Cannot assign to 'b' because it is a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(27,14): error TS2540: Cannot assign to 'c' because it is a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(36,3): error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(40,3): error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(49,3): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(56,3): error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
 tests/cases/compiler/readonlyMembers.ts(62,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
 tests/cases/compiler/readonlyMembers.ts(65,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
 
@@ -23,11 +23,11 @@ tests/cases/compiler/readonlyMembers.ts(65,1): error TS2450: Left-hand side of a
     }
     var x: X = { a: 0 };
     x.a = 1;  // Error
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
     x.b = 1;  // Error
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'b' because it is a constant or a read-only property.
     
     class C {
         readonly a: number;
@@ -37,30 +37,30 @@ tests/cases/compiler/readonlyMembers.ts(65,1): error TS2450: Left-hand side of a
             this.a = 1;  // Ok
             this.b = 1;  // Ok
             this.c = 1;  // Error
-            ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                 ~
+!!! error TS2540: Cannot assign to 'c' because it is a constant or a read-only property.
             const f = () => {
                 this.a = 1;  // Error
-                ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                     ~
+!!! error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
                 this.b = 1;  // Error
-                ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                     ~
+!!! error TS2540: Cannot assign to 'b' because it is a constant or a read-only property.
                 this.c = 1;  // Error
-                ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                     ~
+!!! error TS2540: Cannot assign to 'c' because it is a constant or a read-only property.
             }
         }
         foo() {
             this.a = 1;  // Error
-            ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                 ~
+!!! error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
             this.b = 1;  // Error
-            ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                 ~
+!!! error TS2540: Cannot assign to 'b' because it is a constant or a read-only property.
             this.c = 1;  // Error
-            ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                 ~
+!!! error TS2540: Cannot assign to 'c' because it is a constant or a read-only property.
         }
     }
     
@@ -70,14 +70,14 @@ tests/cases/compiler/readonlyMembers.ts(65,1): error TS2450: Left-hand side of a
         set b(value) { }
     };
     o.a = 1;  // Error
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
     o.b = 1;
     
     var p: { readonly a: number, b: number } = { a: 1, b: 1 };
     p.a = 1;  // Error
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
     p.b = 1;
     var q: { a: number, b: number } = p;
     q.a = 1;
@@ -87,8 +87,8 @@ tests/cases/compiler/readonlyMembers.ts(65,1): error TS2450: Left-hand side of a
         A, B, C
     }
     E.A = 1;  // Error
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     
     namespace N {
         export const a = 1;
@@ -96,8 +96,8 @@ tests/cases/compiler/readonlyMembers.ts(65,1): error TS2450: Left-hand side of a
         export var c = 1;
     }
     N.a = 1;  // Error
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
     N.b = 1;
     N.c = 1;
     
diff --git a/tests/baselines/reference/unionTypeReadonly.errors.txt b/tests/baselines/reference/unionTypeReadonly.errors.txt
index ec660fc3a811f..8248431a93211 100644
--- a/tests/baselines/reference/unionTypeReadonly.errors.txt
+++ b/tests/baselines/reference/unionTypeReadonly.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/conformance/types/union/unionTypeReadonly.ts(17,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/union/unionTypeReadonly.ts(19,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/union/unionTypeReadonly.ts(21,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/union/unionTypeReadonly.ts(23,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/types/union/unionTypeReadonly.ts(17,6): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
+tests/cases/conformance/types/union/unionTypeReadonly.ts(19,11): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
+tests/cases/conformance/types/union/unionTypeReadonly.ts(21,9): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
+tests/cases/conformance/types/union/unionTypeReadonly.ts(23,15): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
 tests/cases/conformance/types/union/unionTypeReadonly.ts(25,15): error TS2339: Property 'value' does not exist on type 'Base | DifferentName'.
   Property 'value' does not exist on type 'DifferentName'.
 
@@ -24,20 +24,20 @@ tests/cases/conformance/types/union/unionTypeReadonly.ts(25,15): error TS2339: P
     }
     let base: Base;
     base.value = 12 // error, lhs can't be a readonly property
-    ~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+         ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     let identical: Base | Identical;
     identical.value = 12; // error, lhs can't be a readonly property
-    ~~~~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+              ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     let mutable: Base | Mutable;
     mutable.value = 12; // error, lhs can't be a readonly property
-    ~~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+            ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     let differentType: Base | DifferentType;
     differentType.value = 12; // error, lhs can't be a readonly property
-    ~~~~~~~~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                  ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     let differentName: Base | DifferentName;
     differentName.value = 12; // error, property 'value' doesn't exist
                   ~~~~~
diff --git a/tests/baselines/reference/validNullAssignments.errors.txt b/tests/baselines/reference/validNullAssignments.errors.txt
index 4ae9522d02357..ae3b0695c9d68 100644
--- a/tests/baselines/reference/validNullAssignments.errors.txt
+++ b/tests/baselines/reference/validNullAssignments.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/types/primitives/null/validNullAssignments.ts(10,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/types/primitives/null/validNullAssignments.ts(10,3): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
 tests/cases/conformance/types/primitives/null/validNullAssignments.ts(15,1): error TS2539: Cannot assign to 'C' because it is not a variable.
 tests/cases/conformance/types/primitives/null/validNullAssignments.ts(20,1): error TS2693: 'I' only refers to a type, but is being used as a value here.
 tests/cases/conformance/types/primitives/null/validNullAssignments.ts(23,1): error TS2539: Cannot assign to 'M' because it is not a variable.
@@ -16,8 +16,8 @@ tests/cases/conformance/types/primitives/null/validNullAssignments.ts(30,1): err
     
     enum E { A }
     E.A = null; // error
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     
     class C { foo: string }
     var f: C;

From 2f34f7c5692c3618a1cee13d9605b7df9f4455d1 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sun, 30 Oct 2016 19:01:07 -0700
Subject: [PATCH 126/224] Improve more error messages

---
 src/compiler/checker.ts              | 12 ++++++------
 src/compiler/diagnosticMessages.json | 12 ++++++++----
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index bf3a4b94d0cc7..0e7e255953fa1 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -13614,7 +13614,7 @@ namespace ts {
                     if (ok) {
                         // run check only if former checks succeeded to avoid reporting cascading errors
                         checkReferenceExpression(node.operand,
-                            Diagnostics.The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_property_or_indexer,
+                            Diagnostics.The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access,
                             Diagnostics.The_operand_of_an_increment_or_decrement_operator_cannot_be_a_constant_or_a_read_only_property);
                     }
                     return numberType;
@@ -13632,7 +13632,7 @@ namespace ts {
             if (ok) {
                 // run check only if former checks succeeded to avoid reporting cascading errors
                 checkReferenceExpression(node.operand,
-                    Diagnostics.The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_property_or_indexer,
+                    Diagnostics.The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access,
                     Diagnostics.The_operand_of_an_increment_or_decrement_operator_cannot_be_a_constant_or_a_read_only_property);
             }
             return numberType;
@@ -13859,7 +13859,7 @@ namespace ts {
 
         function checkReferenceAssignment(target: Expression, sourceType: Type, contextualMapper?: TypeMapper): Type {
             const targetType = checkExpression(target, contextualMapper);
-            if (checkReferenceExpression(target, Diagnostics.Invalid_left_hand_side_of_assignment_expression, Diagnostics.Left_hand_side_of_assignment_expression_cannot_be_a_constant_or_a_read_only_property)) {
+            if (checkReferenceExpression(target, Diagnostics.The_left_hand_side_of_an_assignment_expression_must_be_a_variable_or_a_property_access, Diagnostics.Left_hand_side_of_assignment_expression_cannot_be_a_constant_or_a_read_only_property)) {
                 checkTypeAssignableTo(sourceType, targetType, target, /*headMessage*/ undefined);
             }
             return sourceType;
@@ -14143,7 +14143,7 @@ namespace ts {
                     // A compound assignment furthermore requires VarExpr to be classified as a reference (section 4.1)
                     // and the type of the non - compound operation to be assignable to the type of VarExpr.
                     const ok = checkReferenceExpression(left,
-                        Diagnostics.Invalid_left_hand_side_of_assignment_expression,
+                        Diagnostics.The_left_hand_side_of_an_assignment_expression_must_be_a_variable_or_a_property_access,
                         Diagnostics.Left_hand_side_of_assignment_expression_cannot_be_a_constant_or_a_read_only_property);
                     // Use default messages
                     if (ok) {
@@ -16588,7 +16588,7 @@ namespace ts {
                 }
                 else {
                     const leftType = checkExpression(varExpr);
-                    checkReferenceExpression(varExpr, /*invalidReferenceMessage*/ Diagnostics.Invalid_left_hand_side_in_for_of_statement,
+                    checkReferenceExpression(varExpr, /*invalidReferenceMessage*/ Diagnostics.The_left_hand_side_of_a_for_of_statement_must_be_a_variable_or_a_property_access,
                         /*constantVariableMessage*/ Diagnostics.The_left_hand_side_of_a_for_of_statement_cannot_be_a_constant_or_a_read_only_property);
 
                     // iteratedType will be undefined if the rightType was missing properties/signatures
@@ -16639,7 +16639,7 @@ namespace ts {
                 }
                 else {
                     // run check only former check succeeded to avoid cascading errors
-                    checkReferenceExpression(varExpr, Diagnostics.Invalid_left_hand_side_in_for_in_statement,
+                    checkReferenceExpression(varExpr, Diagnostics.The_left_hand_side_of_a_for_in_statement_must_be_a_variable_or_a_property_access,
                         Diagnostics.The_left_hand_side_of_a_for_in_statement_cannot_be_a_constant_or_a_read_only_property);
                 }
             }
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 85068a4fad5c8..00b6caf612b9b 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1075,7 +1075,7 @@
         "category": "Error",
         "code": 2356
     },
-    "The operand of an increment or decrement operator must be a variable, property or indexer.": {
+    "The operand of an increment or decrement operator must be a variable or a property access.": {
         "category": "Error",
         "code": 2357
     },
@@ -1103,7 +1103,7 @@
         "category": "Error",
         "code": 2363
     },
-    "Invalid left-hand side of assignment expression.": {
+    "The left-hand side of an assignment expression must be a variable or a property access.": {
         "category": "Error",
         "code": 2364
     },
@@ -1263,7 +1263,7 @@
         "category": "Error",
         "code": 2405
     },
-    "Invalid left-hand side in 'for...in' statement.": {
+    "The left-hand side of a 'for...in' statement must be a variable or a property access.": {
         "category": "Error",
         "code": 2406
     },
@@ -1563,7 +1563,7 @@
         "category": "Error",
         "code": 2486
     },
-    "Invalid left-hand side in 'for...of' statement.": {
+    "The left-hand side of a 'for...of' statement must be a variable or a property access.": {
         "category": "Error",
         "code": 2487
     },
@@ -1771,6 +1771,10 @@
         "category": "Error",
         "code": 2540
     },
+    "The target of an assignment must be a variable or a property access.": {
+        "category": "Error",
+        "code": 2541
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600

From f29374402aebae3c682742a837d4090dd6d06927 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sun, 30 Oct 2016 19:01:52 -0700
Subject: [PATCH 127/224] Accept new baselines

---
 .../reference/ES5For-of12.errors.txt          |   4 +-
 .../reference/assignToInvalidLHS.errors.txt   |   4 +-
 .../reference/assignmentLHSIsValue.errors.txt |  96 +++++++-------
 ...nmentToParenthesizedExpression1.errors.txt |   4 +-
 .../compoundAssignmentLHSIsValue.errors.txt   | 120 +++++++++---------
 ...onentiationAssignmentLHSIsValue.errors.txt |  28 ++--
 ...torWithIncompleteTypeAnnotation.errors.txt |   4 +-
 .../decrementAndIncrementOperators.errors.txt |  52 ++++----
 ...thAnyOtherTypeInvalidOperations.errors.txt |  40 +++---
 ...orWithEnumTypeInvalidOperations.errors.txt |   8 +-
 ...WithNumberTypeInvalidOperations.errors.txt |  48 +++----
 tests/baselines/reference/for-of3.errors.txt  |   4 +-
 ...thAnyOtherTypeInvalidOperations.errors.txt |  40 +++---
 ...WithNumberTypeInvalidOperations.errors.txt |  48 +++----
 .../parserAssignmentExpression1.errors.txt    |   4 +-
 .../reference/parserForStatement6.errors.txt  |   4 +-
 .../reference/parserForStatement7.errors.txt  |   4 +-
 .../reference/parserForStatement8.errors.txt  |   4 +-
 ...rserGreaterThanTokenAmbiguity11.errors.txt |   4 +-
 ...rserGreaterThanTokenAmbiguity15.errors.txt |   4 +-
 ...rserGreaterThanTokenAmbiguity16.errors.txt |   4 +-
 ...rserGreaterThanTokenAmbiguity20.errors.txt |   4 +-
 .../parserUnaryExpression1.errors.txt         |   4 +-
 .../parserUnaryExpression7.errors.txt         |   4 +-
 24 files changed, 270 insertions(+), 270 deletions(-)

diff --git a/tests/baselines/reference/ES5For-of12.errors.txt b/tests/baselines/reference/ES5For-of12.errors.txt
index 02ed4c335a6e7..180a32bddb48e 100644
--- a/tests/baselines/reference/ES5For-of12.errors.txt
+++ b/tests/baselines/reference/ES5For-of12.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/conformance/statements/for-ofStatements/ES5For-of12.ts(1,7): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of12.ts(1,7): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 
 
 ==== tests/cases/conformance/statements/for-ofStatements/ES5For-of12.ts (1 errors) ====
     for ([""] of [[""]]) { }
           ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
\ No newline at end of file
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
\ No newline at end of file
diff --git a/tests/baselines/reference/assignToInvalidLHS.errors.txt b/tests/baselines/reference/assignToInvalidLHS.errors.txt
index a39756d15f7f8..b338871606b4f 100644
--- a/tests/baselines/reference/assignToInvalidLHS.errors.txt
+++ b/tests/baselines/reference/assignToInvalidLHS.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/assignToInvalidLHS.ts(4,9): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/assignToInvalidLHS.ts(4,9): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 
 
 ==== tests/cases/compiler/assignToInvalidLHS.ts (1 errors) ====
@@ -7,4 +7,4 @@ tests/cases/compiler/assignToInvalidLHS.ts(4,9): error TS2364: Invalid left-hand
     // Below is actually valid JavaScript (see http://es5.github.com/#x8.7 ), even though will always fail at runtime with 'invalid left-hand side'
     var x = new y = 5;
             ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
\ No newline at end of file
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
\ No newline at end of file
diff --git a/tests/baselines/reference/assignmentLHSIsValue.errors.txt b/tests/baselines/reference/assignmentLHSIsValue.errors.txt
index a8772e7eec647..01de8d33441a5 100644
--- a/tests/baselines/reference/assignmentLHSIsValue.errors.txt
+++ b/tests/baselines/reference/assignmentLHSIsValue.errors.txt
@@ -1,42 +1,42 @@
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(6,21): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7,13): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(8,21): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(11,18): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(13,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(6,21): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7,13): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(8,21): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(11,18): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(13,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(17,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(19,1): error TS2539: Cannot assign to 'C' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(22,1): error TS2539: Cannot assign to 'E' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(24,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(27,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(28,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(29,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(30,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(31,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(32,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(27,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(28,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(29,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(30,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(31,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(32,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(35,3): error TS7028: Unused label.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(35,9): error TS1128: Declaration or statement expected.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(38,2): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(38,6): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(38,2): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(38,6): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(42,36): error TS1034: 'super' must be followed by an argument list or member access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(44,19): error TS1034: 'super' must be followed by an argument list or member access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(46,27): error TS1034: 'super' must be followed by an argument list or member access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(50,20): error TS1128: Declaration or statement expected.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(51,11): error TS1005: ';' expected.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(54,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(57,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(54,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(57,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(58,2): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(59,2): error TS2539: Cannot assign to 'C' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(60,2): error TS2539: Cannot assign to 'E' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(61,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(62,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(63,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(64,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(65,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(66,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(67,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(68,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(69,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(70,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(62,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(63,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(64,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(65,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(66,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(67,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(68,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(69,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(70,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 
 
 ==== tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts (39 errors) ====
@@ -47,22 +47,22 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
     class C {
         constructor() { this = value; }
                         ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
         foo() { this = value; }
                 ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
         static sfoo() { this = value; }
                         ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     }
     
     function foo() { this = value; }
                      ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     this = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // identifiers: module, class, enum, function
     module M { export var a; }
@@ -86,22 +86,22 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
     // literals
     null = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     true = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     false = value;
     ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     0 = value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     '' = value;
     ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     /d+/ = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // object literals
     { a: 0} = value;
@@ -113,9 +113,9 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
     // array literals
     ['', ''] = value;
      ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
          ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // super
     class Derived extends C {
@@ -143,12 +143,12 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
     // function calls
     foo() = value;
     ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // parentheses, the containted expression is value
     (this) = value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (M) = value;
      ~
 !!! error TS2539: Cannot assign to 'M' because it is not a variable.
@@ -163,28 +163,28 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
 !!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     (null) = value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (true) = value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (0) = value;
     ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ('') = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (/d+/) = value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ({}) = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ([]) = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (function baz() { }) = value;
     ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (foo()) = value;
     ~~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
\ No newline at end of file
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
\ No newline at end of file
diff --git a/tests/baselines/reference/assignmentToParenthesizedExpression1.errors.txt b/tests/baselines/reference/assignmentToParenthesizedExpression1.errors.txt
index 0a411828bf939..ff8fa5d22b2ea 100644
--- a/tests/baselines/reference/assignmentToParenthesizedExpression1.errors.txt
+++ b/tests/baselines/reference/assignmentToParenthesizedExpression1.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/assignmentToParenthesizedExpression1.ts(2,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/assignmentToParenthesizedExpression1.ts(2,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/compiler/assignmentToParenthesizedExpression1.ts(2,2): error TS2695: Left side of comma operator is unused and has no side effects.
 
 
@@ -6,6 +6,6 @@ tests/cases/compiler/assignmentToParenthesizedExpression1.ts(2,2): error TS2695:
     var x;
     (1, x)=0;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
      ~
 !!! error TS2695: Left side of comma operator is unused and has no side effects.
\ No newline at end of file
diff --git a/tests/baselines/reference/compoundAssignmentLHSIsValue.errors.txt b/tests/baselines/reference/compoundAssignmentLHSIsValue.errors.txt
index c4508c7e0b9a5..bc6bb41b27f4f 100644
--- a/tests/baselines/reference/compoundAssignmentLHSIsValue.errors.txt
+++ b/tests/baselines/reference/compoundAssignmentLHSIsValue.errors.txt
@@ -1,13 +1,13 @@
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(8,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(9,9): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(9,9): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(12,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(13,9): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(13,9): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(16,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(17,9): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(22,5): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(23,5): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(26,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(27,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(17,9): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(22,5): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(23,5): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(26,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(27,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(31,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(32,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(34,1): error TS2539: Cannot assign to 'C' because it is not a variable.
@@ -16,22 +16,22 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(39,1): error TS2539: Cannot assign to 'E' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(41,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(42,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(45,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(46,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(45,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(46,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(47,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(48,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(48,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(49,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(50,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(51,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(52,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(50,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(51,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(52,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(53,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(54,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(54,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(55,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(56,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(56,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(59,9): error TS1128: Declaration or statement expected.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(60,9): error TS1128: Declaration or statement expected.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(63,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(64,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(64,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(70,15): error TS1034: 'super' must be followed by an argument list or member access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(71,15): error TS1034: 'super' must be followed by an argument list or member access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(75,15): error TS1034: 'super' must be followed by an argument list or member access.
@@ -43,9 +43,9 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(88,11): error TS1005: ';' expected.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(89,11): error TS1005: ';' expected.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(92,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(93,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(96,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(97,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(93,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(96,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(97,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(98,2): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(99,2): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(100,2): error TS2539: Cannot assign to 'C' because it is not a variable.
@@ -54,24 +54,24 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(103,2): error TS2539: Cannot assign to 'E' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(104,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(105,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(106,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(107,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(106,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(107,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(108,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(109,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(110,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(111,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(109,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(110,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(111,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(112,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(113,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(113,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(114,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(115,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(115,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(116,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(117,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(117,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(118,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(119,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(119,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(120,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(121,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(121,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(122,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(123,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(123,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 
 
 ==== tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts (74 errors) ====
@@ -87,7 +87,7 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
             this += value;
             ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
         }
         foo() {
             this *= value;
@@ -95,7 +95,7 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
             this += value;
             ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
         }
         static sfoo() {
             this *= value;
@@ -103,25 +103,25 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
             this += value;
             ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
         }
     }
     
     function foo() {
         this *= value;
         ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
         this += value;
         ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     }
     
     this *= value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     this += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // identifiers: module, class, enum, function
     module M { export var a; }
@@ -157,40 +157,40 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
     // literals
     null *= value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     null += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     true *= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     true += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     false *= value;
     ~~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     false += value;
     ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     0 *= value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     0 += value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     '' *= value;
     ~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     '' += value;
     ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     /d+/ *= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     /d+/ += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // object literals
     { a: 0} *= value;
@@ -206,7 +206,7 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     ['', ''] += value;
     ~~~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // super
     class Derived extends C {
@@ -259,15 +259,15 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     foo() += value;
     ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // parentheses, the containted expression is value
     (this) *= value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (this) += value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (M) *= value;
      ~
 !!! error TS2539: Cannot assign to 'M' because it is not a variable.
@@ -294,55 +294,55 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 !!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     (null) *= value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (null) += value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (true) *= value;
     ~~~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     (true) += value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (0) *= value;
     ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (0) += value;
     ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ('') *= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     ('') += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (/d+/) *= value;
     ~~~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     (/d+/) += value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ({}) *= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     ({}) += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ([]) *= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     ([]) += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (function baz1() { }) *= value;
     ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     (function baz2() { }) += value;
     ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (foo()) *= value;
     ~~~~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     (foo()) += value;
     ~~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
\ No newline at end of file
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
\ No newline at end of file
diff --git a/tests/baselines/reference/compoundExponentiationAssignmentLHSIsValue.errors.txt b/tests/baselines/reference/compoundExponentiationAssignmentLHSIsValue.errors.txt
index 0871f3944b66e..22eeb18ac4ad1 100644
--- a/tests/baselines/reference/compoundExponentiationAssignmentLHSIsValue.errors.txt
+++ b/tests/baselines/reference/compoundExponentiationAssignmentLHSIsValue.errors.txt
@@ -1,16 +1,16 @@
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(7,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(10,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(13,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(18,5): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(21,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(18,5): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(21,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(25,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(27,1): error TS2539: Cannot assign to 'C' because it is not a variable.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(30,1): error TS2539: Cannot assign to 'E' because it is not a variable.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(32,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(35,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(35,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(36,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(37,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(38,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(38,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(39,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(40,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(43,3): error TS7028: Unused label.
@@ -22,14 +22,14 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(65,21): error TS1128: Declaration or statement expected.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(66,11): error TS1005: ';' expected.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(69,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(72,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(72,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(73,2): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(74,2): error TS2539: Cannot assign to 'C' because it is not a variable.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(75,2): error TS2539: Cannot assign to 'E' because it is not a variable.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(76,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(77,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(77,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(78,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(79,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(79,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(80,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(81,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(82,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
@@ -64,12 +64,12 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
     function foo() {
         this **= value;
         ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     }
     
     this **= value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // identifiers: module, class, enum, function
     module M { export var a; }
@@ -93,7 +93,7 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
     // literals
     null **= value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     true **= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
@@ -102,7 +102,7 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     0 **= value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     '' **= value;
     ~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
@@ -160,7 +160,7 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
     // parentheses, the containted expression is value
     (this) **= value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (M) **= value;
      ~
 !!! error TS2539: Cannot assign to 'M' because it is not a variable.
@@ -175,13 +175,13 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
 !!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     (null) **= value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (true) **= value;
     ~~~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     (0) **= value;
     ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ('') **= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
diff --git a/tests/baselines/reference/constructorWithIncompleteTypeAnnotation.errors.txt b/tests/baselines/reference/constructorWithIncompleteTypeAnnotation.errors.txt
index 49d3e3788551f..2854e73d935d8 100644
--- a/tests/baselines/reference/constructorWithIncompleteTypeAnnotation.errors.txt
+++ b/tests/baselines/reference/constructorWithIncompleteTypeAnnotation.errors.txt
@@ -25,7 +25,7 @@ tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(59,5): error TS1
 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(70,13): error TS1109: Expression expected.
 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(73,37): error TS1127: Invalid character.
 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(82,13): error TS1109: Expression expected.
-tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(90,23): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(90,23): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(91,13): error TS1109: Expression expected.
 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(106,29): error TS1109: Expression expected.
 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(107,13): error TS1109: Expression expected.
@@ -236,7 +236,7 @@ tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(262,1): error TS
                 //
                 var any = 0 ^= 
                           ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
                 var bool = 0;
                 ~~~
 !!! error TS1109: Expression expected.
diff --git a/tests/baselines/reference/decrementAndIncrementOperators.errors.txt b/tests/baselines/reference/decrementAndIncrementOperators.errors.txt
index ec58db836a631..f8a0b5dcd829b 100644
--- a/tests/baselines/reference/decrementAndIncrementOperators.errors.txt
+++ b/tests/baselines/reference/decrementAndIncrementOperators.errors.txt
@@ -1,16 +1,16 @@
-tests/cases/compiler/decrementAndIncrementOperators.ts(4,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(6,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(7,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(9,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(10,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(12,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(13,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(15,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(16,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(18,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(19,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(21,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(22,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/compiler/decrementAndIncrementOperators.ts(4,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(6,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(7,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(9,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(10,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(12,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(13,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(15,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(16,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(18,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(19,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(21,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(22,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 
 
 ==== tests/cases/compiler/decrementAndIncrementOperators.ts (13 errors) ====
@@ -19,49 +19,49 @@ tests/cases/compiler/decrementAndIncrementOperators.ts(22,3): error TS2357: The
     // errors
     1 ++;
     ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     (1)++;
     ~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     (1)--;
     ~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     ++(1);
       ~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     --(1);
       ~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     (1 + 2)++;
     ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     (1 + 2)--;
     ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     ++(1 + 2);
       ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     --(1 + 2);
       ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     (x + x)++;
     ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     (x + x)--;
     ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     ++(x + x);
       ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     --(x + x);
       ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     //OK
     x++;
diff --git a/tests/baselines/reference/decrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt b/tests/baselines/reference/decrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt
index a796534af30e3..e42b6ff67b42c 100644
--- a/tests/baselines/reference/decrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt
+++ b/tests/baselines/reference/decrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt
@@ -14,23 +14,23 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(41,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(42,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(43,24): error TS2539: Cannot assign to 'undefined' because it is not a variable.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(46,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(47,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(46,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(47,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,27): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(49,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(49,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(49,27): error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(50,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(50,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(50,27): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(51,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(52,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(54,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(55,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(56,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(54,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(55,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(56,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(56,25): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(57,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(57,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(57,25): error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(58,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(58,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(58,25): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(59,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(60,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -130,23 +130,23 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     // any type expressions
     var ResultIsNumber17 = --foo();
                              ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber18 = --A.foo();
                              ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber19 = --(null + undefined);
                              ~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                               ~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber20 = --(null + null);
                              ~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                               ~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
     var ResultIsNumber21 = --(undefined + undefined);
                              ~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                               ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber22 = --obj1.x;
@@ -158,23 +158,23 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     
     var ResultIsNumber24 = foo()--;
                            ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber25 = A.foo()--;
                            ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber26 = (null + undefined)--;
                            ~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                             ~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber27 = (null + null)--;
                            ~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                             ~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
     var ResultIsNumber28 = (undefined + undefined)--;
                            ~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                             ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber29 = obj1.x--;
diff --git a/tests/baselines/reference/decrementOperatorWithEnumTypeInvalidOperations.errors.txt b/tests/baselines/reference/decrementOperatorWithEnumTypeInvalidOperations.errors.txt
index bd4223786a214..0a79432c59cf9 100644
--- a/tests/baselines/reference/decrementOperatorWithEnumTypeInvalidOperations.errors.txt
+++ b/tests/baselines/reference/decrementOperatorWithEnumTypeInvalidOperations.errors.txt
@@ -2,9 +2,9 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(8,25): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(10,23): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(11,23): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(14,25): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(14,25): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(14,43): error TS2339: Property 'B' does not exist on type 'typeof ENUM'.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(15,23): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(15,23): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(15,29): error TS2339: Property 'A' does not exist on type 'typeof ENUM'.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(18,3): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(19,3): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
@@ -36,12 +36,12 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     // enum type expressions
     var ResultIsNumber5 = --(ENUM["A"] + ENUM.B);
                             ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                                               ~
 !!! error TS2339: Property 'B' does not exist on type 'typeof ENUM'.
     var ResultIsNumber6 = (ENUM.A + ENUM["B"])--;
                           ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                                 ~
 !!! error TS2339: Property 'A' does not exist on type 'typeof ENUM'.
     
diff --git a/tests/baselines/reference/decrementOperatorWithNumberTypeInvalidOperations.errors.txt b/tests/baselines/reference/decrementOperatorWithNumberTypeInvalidOperations.errors.txt
index 8df7e50809961..8cf459cb79033 100644
--- a/tests/baselines/reference/decrementOperatorWithNumberTypeInvalidOperations.errors.txt
+++ b/tests/baselines/reference/decrementOperatorWithNumberTypeInvalidOperations.errors.txt
@@ -1,23 +1,23 @@
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(18,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(19,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(22,25): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(22,25): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(23,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(24,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(26,23): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(26,23): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(27,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(28,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(31,25): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(32,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(33,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(35,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(36,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(37,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(40,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(31,25): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(32,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(33,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(35,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(36,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(37,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(40,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(41,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(42,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(44,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(42,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(44,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(45,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(46,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(46,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 
 
 ==== tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts (20 errors) ====
@@ -48,7 +48,7 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     // number type literal
     var ResultIsNumber3 = --1;
                             ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber4 = --{ x: 1, y: 2};
                             ~~~~~~~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -58,7 +58,7 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     
     var ResultIsNumber6 = 1--;
                           ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber7 = { x: 1, y: 2 }--;
                           ~~~~~~~~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -69,41 +69,41 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     // number type expressions
     var ResultIsNumber9 = --foo();
                             ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber10 = --A.foo();
                              ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber11 = --(NUMBER + NUMBER);
                              ~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     var ResultIsNumber12 = foo()--;
                            ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber13 = A.foo()--;
                            ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber14 = (NUMBER + NUMBER)--;
                            ~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     // miss assignment operator
     --1;
       ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     --NUMBER1;
       ~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     --foo();
       ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     1--;
     ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     NUMBER1--;
     ~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     foo()--;
     ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
\ No newline at end of file
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
\ No newline at end of file
diff --git a/tests/baselines/reference/for-of3.errors.txt b/tests/baselines/reference/for-of3.errors.txt
index 99ed3098a6389..1d58db6f186b7 100644
--- a/tests/baselines/reference/for-of3.errors.txt
+++ b/tests/baselines/reference/for-of3.errors.txt
@@ -1,8 +1,8 @@
-tests/cases/conformance/es6/for-ofStatements/for-of3.ts(2,6): error TS2487: Invalid left-hand side in 'for...of' statement.
+tests/cases/conformance/es6/for-ofStatements/for-of3.ts(2,6): error TS2487: The left-hand side of a 'for...of' statement must be a variable or a property access.
 
 
 ==== tests/cases/conformance/es6/for-ofStatements/for-of3.ts (1 errors) ====
     var v: any;
     for (v++ of []) { }
          ~~~
-!!! error TS2487: Invalid left-hand side in 'for...of' statement.
\ No newline at end of file
+!!! error TS2487: The left-hand side of a 'for...of' statement must be a variable or a property access.
\ No newline at end of file
diff --git a/tests/baselines/reference/incrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt b/tests/baselines/reference/incrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt
index be17df7db927d..0a303d12bf37a 100644
--- a/tests/baselines/reference/incrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt
+++ b/tests/baselines/reference/incrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt
@@ -14,23 +14,23 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(41,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(42,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(43,24): error TS2539: Cannot assign to 'undefined' because it is not a variable.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(46,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(47,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(46,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(47,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,27): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(49,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(49,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(49,27): error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(50,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(50,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(50,27): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(51,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(52,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(54,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(55,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(56,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(54,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(55,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(56,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(56,25): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(57,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(57,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(57,25): error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(58,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(58,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(58,25): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(59,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(60,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -125,23 +125,23 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     // any type expressions
     var ResultIsNumber17 = ++foo();
                              ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber18 = ++A.foo();
                              ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber19 = ++(null + undefined);
                              ~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                               ~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber20 = ++(null + null);
                              ~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                               ~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
     var ResultIsNumber21 = ++(undefined + undefined);
                              ~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                               ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber22 = ++obj1.x;
@@ -153,23 +153,23 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     
     var ResultIsNumber24 = foo()++;
                            ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber25 = A.foo()++;
                            ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber26 = (null + undefined)++;
                            ~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                             ~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber27 = (null + null)++;
                            ~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                             ~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
     var ResultIsNumber28 = (undefined + undefined)++;
                            ~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                             ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber29 = obj1.x++;
diff --git a/tests/baselines/reference/incrementOperatorWithNumberTypeInvalidOperations.errors.txt b/tests/baselines/reference/incrementOperatorWithNumberTypeInvalidOperations.errors.txt
index 71c3ad67c4665..093a41aa35557 100644
--- a/tests/baselines/reference/incrementOperatorWithNumberTypeInvalidOperations.errors.txt
+++ b/tests/baselines/reference/incrementOperatorWithNumberTypeInvalidOperations.errors.txt
@@ -1,23 +1,23 @@
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(18,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(19,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(22,25): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(22,25): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(23,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(24,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(26,23): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(26,23): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(27,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(28,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(31,25): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(32,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(33,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(35,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(36,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(37,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(40,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(31,25): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(32,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(33,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(35,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(36,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(37,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(40,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(41,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(42,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(44,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(42,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(44,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(45,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(46,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(46,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 
 
 ==== tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts (20 errors) ====
@@ -48,7 +48,7 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     // number type literal
     var ResultIsNumber3 = ++1;
                             ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber4 = ++{ x: 1, y: 2};
                             ~~~~~~~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -58,7 +58,7 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     
     var ResultIsNumber6 = 1++;
                           ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber7 = { x: 1, y: 2 }++;
                           ~~~~~~~~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -69,41 +69,41 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     // number type expressions
     var ResultIsNumber9 = ++foo();
                             ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber10 = ++A.foo();
                              ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber11 = ++(NUMBER + NUMBER);
                              ~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     var ResultIsNumber12 = foo()++;
                            ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber13 = A.foo()++;
                            ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber14 = (NUMBER + NUMBER)++;
                            ~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     // miss assignment operator
     ++1;
       ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     ++NUMBER1;
       ~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     ++foo();
       ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     1++;
     ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     NUMBER1++;
     ~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     foo()++;
     ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
\ No newline at end of file
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
\ No newline at end of file
diff --git a/tests/baselines/reference/parserAssignmentExpression1.errors.txt b/tests/baselines/reference/parserAssignmentExpression1.errors.txt
index 70eecd81b39e6..4a5891eb6a99e 100644
--- a/tests/baselines/reference/parserAssignmentExpression1.errors.txt
+++ b/tests/baselines/reference/parserAssignmentExpression1.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/parser/ecmascript5/Expressions/parserAssignmentExpression1.ts(1,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/parser/ecmascript5/Expressions/parserAssignmentExpression1.ts(1,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/parser/ecmascript5/Expressions/parserAssignmentExpression1.ts(1,2): error TS2304: Cannot find name 'foo'.
 tests/cases/conformance/parser/ecmascript5/Expressions/parserAssignmentExpression1.ts(1,11): error TS2304: Cannot find name 'bar'.
 
@@ -6,7 +6,7 @@ tests/cases/conformance/parser/ecmascript5/Expressions/parserAssignmentExpressio
 ==== tests/cases/conformance/parser/ecmascript5/Expressions/parserAssignmentExpression1.ts (3 errors) ====
     (foo()) = bar;
     ~~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
      ~~~
 !!! error TS2304: Cannot find name 'foo'.
               ~~~
diff --git a/tests/baselines/reference/parserForStatement6.errors.txt b/tests/baselines/reference/parserForStatement6.errors.txt
index a41f103e929ca..808a166afad46 100644
--- a/tests/baselines/reference/parserForStatement6.errors.txt
+++ b/tests/baselines/reference/parserForStatement6.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement6.ts(1,6): error TS2304: Cannot find name 'foo'.
-tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement6.ts(1,6): error TS2406: Invalid left-hand side in 'for...in' statement.
+tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement6.ts(1,6): error TS2406: The left-hand side of a 'for...in' statement must be a variable or a property access.
 tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement6.ts(1,15): error TS2304: Cannot find name 'b'.
 
 
@@ -8,7 +8,7 @@ tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement6.ts(1,1
          ~~~
 !!! error TS2304: Cannot find name 'foo'.
          ~~~~~
-!!! error TS2406: Invalid left-hand side in 'for...in' statement.
+!!! error TS2406: The left-hand side of a 'for...in' statement must be a variable or a property access.
                   ~
 !!! error TS2304: Cannot find name 'b'.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/parserForStatement7.errors.txt b/tests/baselines/reference/parserForStatement7.errors.txt
index 3aa67480105aa..1fd3648074415 100644
--- a/tests/baselines/reference/parserForStatement7.errors.txt
+++ b/tests/baselines/reference/parserForStatement7.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement7.ts(1,6): error TS2406: Invalid left-hand side in 'for...in' statement.
+tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement7.ts(1,6): error TS2406: The left-hand side of a 'for...in' statement must be a variable or a property access.
 tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement7.ts(1,10): error TS2304: Cannot find name 'foo'.
 tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement7.ts(1,19): error TS2304: Cannot find name 'b'.
 
@@ -6,7 +6,7 @@ tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement7.ts(1,1
 ==== tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement7.ts (3 errors) ====
     for (new foo() in b) {
          ~~~~~~~~~
-!!! error TS2406: Invalid left-hand side in 'for...in' statement.
+!!! error TS2406: The left-hand side of a 'for...in' statement must be a variable or a property access.
              ~~~
 !!! error TS2304: Cannot find name 'foo'.
                       ~
diff --git a/tests/baselines/reference/parserForStatement8.errors.txt b/tests/baselines/reference/parserForStatement8.errors.txt
index 72c7901aa8c53..21ea55e3b09f1 100644
--- a/tests/baselines/reference/parserForStatement8.errors.txt
+++ b/tests/baselines/reference/parserForStatement8.errors.txt
@@ -1,11 +1,11 @@
-tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement8.ts(1,6): error TS2406: Invalid left-hand side in 'for...in' statement.
+tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement8.ts(1,6): error TS2406: The left-hand side of a 'for...in' statement must be a variable or a property access.
 tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement8.ts(1,14): error TS2304: Cannot find name 'b'.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement8.ts (2 errors) ====
     for (this in b) {
          ~~~~
-!!! error TS2406: Invalid left-hand side in 'for...in' statement.
+!!! error TS2406: The left-hand side of a 'for...in' statement must be a variable or a property access.
                  ~
 !!! error TS2304: Cannot find name 'b'.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/parserGreaterThanTokenAmbiguity11.errors.txt b/tests/baselines/reference/parserGreaterThanTokenAmbiguity11.errors.txt
index 8ccafdaf094a6..2c179256c77c0 100644
--- a/tests/baselines/reference/parserGreaterThanTokenAmbiguity11.errors.txt
+++ b/tests/baselines/reference/parserGreaterThanTokenAmbiguity11.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/conformance/parser/ecmascript5/Generics/parserGreaterThanTokenAmbiguity11.ts(1,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/parser/ecmascript5/Generics/parserGreaterThanTokenAmbiguity11.ts(1,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/Generics/parserGreaterThanTokenAmbiguity11.ts (1 errors) ====
     1 >>= 2;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
\ No newline at end of file
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
\ No newline at end of file
diff --git a/tests/baselines/reference/parserGreaterThanTokenAmbiguity15.errors.txt b/tests/baselines/reference/parserGreaterThanTokenAmbiguity15.errors.txt
index 12bba7ec8f55c..3c2c9c45d3396 100644
--- a/tests/baselines/reference/parserGreaterThanTokenAmbiguity15.errors.txt
+++ b/tests/baselines/reference/parserGreaterThanTokenAmbiguity15.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/conformance/parser/ecmascript5/Generics/parserGreaterThanTokenAmbiguity15.ts(1,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/parser/ecmascript5/Generics/parserGreaterThanTokenAmbiguity15.ts(1,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/Generics/parserGreaterThanTokenAmbiguity15.ts (1 errors) ====
     1 
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     // before
     >>= // after
     2;
\ No newline at end of file
diff --git a/tests/baselines/reference/parserGreaterThanTokenAmbiguity16.errors.txt b/tests/baselines/reference/parserGreaterThanTokenAmbiguity16.errors.txt
index eb31b49621e9c..fd2f07bda819c 100644
--- a/tests/baselines/reference/parserGreaterThanTokenAmbiguity16.errors.txt
+++ b/tests/baselines/reference/parserGreaterThanTokenAmbiguity16.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/conformance/parser/ecmascript5/Generics/parserGreaterThanTokenAmbiguity16.ts(1,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/parser/ecmascript5/Generics/parserGreaterThanTokenAmbiguity16.ts(1,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/Generics/parserGreaterThanTokenAmbiguity16.ts (1 errors) ====
     1 >>>= 2;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
\ No newline at end of file
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
\ No newline at end of file
diff --git a/tests/baselines/reference/parserGreaterThanTokenAmbiguity20.errors.txt b/tests/baselines/reference/parserGreaterThanTokenAmbiguity20.errors.txt
index c464bc37ff85c..d5aa2b1269bb9 100644
--- a/tests/baselines/reference/parserGreaterThanTokenAmbiguity20.errors.txt
+++ b/tests/baselines/reference/parserGreaterThanTokenAmbiguity20.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/conformance/parser/ecmascript5/Generics/parserGreaterThanTokenAmbiguity20.ts(1,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/parser/ecmascript5/Generics/parserGreaterThanTokenAmbiguity20.ts(1,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/Generics/parserGreaterThanTokenAmbiguity20.ts (1 errors) ====
     1
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     // Before
     >>>= // after
     2;
\ No newline at end of file
diff --git a/tests/baselines/reference/parserUnaryExpression1.errors.txt b/tests/baselines/reference/parserUnaryExpression1.errors.txt
index 16900ea616076..278960d53f31b 100644
--- a/tests/baselines/reference/parserUnaryExpression1.errors.txt
+++ b/tests/baselines/reference/parserUnaryExpression1.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/conformance/parser/ecmascript5/Expressions/parserUnaryExpression1.ts(1,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/parser/ecmascript5/Expressions/parserUnaryExpression1.ts(1,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/Expressions/parserUnaryExpression1.ts (1 errors) ====
     ++this;
       ~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
\ No newline at end of file
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
\ No newline at end of file
diff --git a/tests/baselines/reference/parserUnaryExpression7.errors.txt b/tests/baselines/reference/parserUnaryExpression7.errors.txt
index 32967d2e0b80b..f69f8e882525f 100644
--- a/tests/baselines/reference/parserUnaryExpression7.errors.txt
+++ b/tests/baselines/reference/parserUnaryExpression7.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/conformance/parser/ecmascript5/Expressions/parserUnaryExpression7.ts(1,4): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/parser/ecmascript5/Expressions/parserUnaryExpression7.ts(1,4): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/parser/ecmascript5/Expressions/parserUnaryExpression7.ts(1,8): error TS2304: Cannot find name 'Foo'.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/Expressions/parserUnaryExpression7.ts (2 errors) ====
     ++ new Foo();
        ~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
            ~~~
 !!! error TS2304: Cannot find name 'Foo'.
\ No newline at end of file

From 03ce7b0145a190b498982d4618c0ca7667f5b1f9 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Mon, 31 Oct 2016 08:23:02 -0700
Subject: [PATCH 128/224] Fix realPathMap in test harness: Must be used in
 `directoryExists`

---
 src/harness/harness.ts                        | 18 ++++-
 .../moduleResolutionWithSymlinks.errors.txt   | 21 ------
 .../reference/moduleResolutionWithSymlinks.js |  2 +-
 .../moduleResolutionWithSymlinks.symbols      | 37 ++++++++++
 .../moduleResolutionWithSymlinks.trace.json   | 73 +------------------
 .../moduleResolutionWithSymlinks.types        | 39 ++++++++++
 .../compiler/moduleResolutionWithSymlinks.ts  |  2 +-
 7 files changed, 96 insertions(+), 96 deletions(-)
 delete mode 100644 tests/baselines/reference/moduleResolutionWithSymlinks.errors.txt
 create mode 100644 tests/baselines/reference/moduleResolutionWithSymlinks.symbols
 create mode 100644 tests/baselines/reference/moduleResolutionWithSymlinks.types

diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index 17e67b053a3ee..add3046abc21e 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -1029,7 +1029,7 @@ namespace Harness {
                 },
                 realpath: realPathMap && ((f: string) => {
                     const path = ts.toPath(f, currentDirectory, getCanonicalFileName);
-                    return realPathMap.contains(path) ? realPathMap.get(path) : path;
+                    return realPathMap.get(path) || path;
                 }),
                 directoryExists: dir => {
                     let path = ts.toPath(dir, currentDirectory, getCanonicalFileName);
@@ -1037,12 +1037,20 @@ namespace Harness {
                     if (path[path.length - 1] === "/") {
                         path = <ts.Path>path.substr(0, path.length - 1);
                     }
+
                     let exists = false;
-                    fileMap.forEachValue(key => {
-                        if (key.indexOf(path) === 0 && key[path.length] === "/") {
+                    fileMap.forEachValue(fileName => {
+                        if (!exists && pathStartsWithDirectory(fileName, path)) {
                             exists = true;
                         }
                     });
+                    if (!exists && realPathMap) {
+                        realPathMap.forEachValue(fileName => {
+                            if (!exists && pathStartsWithDirectory(fileName, path)) {
+                                exists = true;
+                            }
+                        });
+                    }
                     return exists;
                 },
                 getDirectories: d => {
@@ -1064,6 +1072,10 @@ namespace Harness {
             };
         }
 
+        function pathStartsWithDirectory(fileName: string, directory: string) {
+            return ts.startsWith(fileName, directory) && fileName[directory.length] === "/";
+        }
+
         interface HarnessOptions {
             useCaseSensitiveFileNames?: boolean;
             includeBuiltFile?: string;
diff --git a/tests/baselines/reference/moduleResolutionWithSymlinks.errors.txt b/tests/baselines/reference/moduleResolutionWithSymlinks.errors.txt
deleted file mode 100644
index b51933902a469..0000000000000
--- a/tests/baselines/reference/moduleResolutionWithSymlinks.errors.txt
+++ /dev/null
@@ -1,21 +0,0 @@
-/src/library-b/index.ts(1,23): error TS2307: Cannot find module 'library-a'.
-
-
-==== /src/app.ts (0 errors) ====
-    import { MyClass } from "./library-a";
-    import { MyClass2 } from "./library-b";
-    
-    let x: MyClass;
-    let y: MyClass2;
-    x = y;
-    y = x;
-==== /src/library-a/index.ts (0 errors) ====
-    
-    export class MyClass{}
-    
-==== /src/library-b/index.ts (1 errors) ====
-    import {MyClass} from "library-a";
-                          ~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'library-a'.
-    export { MyClass as MyClass2 }
-    
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithSymlinks.js b/tests/baselines/reference/moduleResolutionWithSymlinks.js
index 4123430045ebb..fa6fea5520b99 100644
--- a/tests/baselines/reference/moduleResolutionWithSymlinks.js
+++ b/tests/baselines/reference/moduleResolutionWithSymlinks.js
@@ -2,7 +2,7 @@
 
 //// [index.ts]
 
-export class MyClass{}
+export class MyClass { private x: number; }
 
 //// [index.ts]
 import {MyClass} from "library-a";
diff --git a/tests/baselines/reference/moduleResolutionWithSymlinks.symbols b/tests/baselines/reference/moduleResolutionWithSymlinks.symbols
new file mode 100644
index 0000000000000..9e9e3ee8a6709
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithSymlinks.symbols
@@ -0,0 +1,37 @@
+=== /src/app.ts ===
+import { MyClass } from "./library-a";
+>MyClass : Symbol(MyClass, Decl(app.ts, 0, 8))
+
+import { MyClass2 } from "./library-b";
+>MyClass2 : Symbol(MyClass2, Decl(app.ts, 1, 8))
+
+let x: MyClass;
+>x : Symbol(x, Decl(app.ts, 3, 3))
+>MyClass : Symbol(MyClass, Decl(app.ts, 0, 8))
+
+let y: MyClass2;
+>y : Symbol(y, Decl(app.ts, 4, 3))
+>MyClass2 : Symbol(MyClass2, Decl(app.ts, 1, 8))
+
+x = y;
+>x : Symbol(x, Decl(app.ts, 3, 3))
+>y : Symbol(y, Decl(app.ts, 4, 3))
+
+y = x;
+>y : Symbol(y, Decl(app.ts, 4, 3))
+>x : Symbol(x, Decl(app.ts, 3, 3))
+
+=== /src/library-a/index.ts ===
+
+export class MyClass { private x: number; }
+>MyClass : Symbol(MyClass, Decl(index.ts, 0, 0))
+>x : Symbol(MyClass.x, Decl(index.ts, 1, 22))
+
+=== /src/library-b/index.ts ===
+import {MyClass} from "library-a";
+>MyClass : Symbol(MyClass, Decl(index.ts, 0, 8))
+
+export { MyClass as MyClass2 }
+>MyClass : Symbol(MyClass2, Decl(index.ts, 1, 8))
+>MyClass2 : Symbol(MyClass2, Decl(index.ts, 1, 8))
+
diff --git a/tests/baselines/reference/moduleResolutionWithSymlinks.trace.json b/tests/baselines/reference/moduleResolutionWithSymlinks.trace.json
index 0f4dd90569a05..7f1c289018096 100644
--- a/tests/baselines/reference/moduleResolutionWithSymlinks.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithSymlinks.trace.json
@@ -26,74 +26,7 @@
     "File '/src/library-b/node_modules/library-a.tsx' does not exist.",
     "File '/src/library-b/node_modules/library-a.d.ts' does not exist.",
     "File '/src/library-b/node_modules/library-a/package.json' does not exist.",
-    "File '/src/library-b/node_modules/library-a/index.ts' does not exist.",
-    "File '/src/library-b/node_modules/library-a/index.tsx' does not exist.",
-    "File '/src/library-b/node_modules/library-a/index.d.ts' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a.ts' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a.tsx' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a.d.ts' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a/package.json' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a/index.ts' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a/index.tsx' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a/index.d.ts' does not exist.",
-    "File '/src/node_modules/library-a.ts' does not exist.",
-    "File '/src/node_modules/library-a.tsx' does not exist.",
-    "File '/src/node_modules/library-a.d.ts' does not exist.",
-    "File '/src/node_modules/library-a/package.json' does not exist.",
-    "File '/src/node_modules/library-a/index.ts' does not exist.",
-    "File '/src/node_modules/library-a/index.tsx' does not exist.",
-    "File '/src/node_modules/library-a/index.d.ts' does not exist.",
-    "File '/src/node_modules/@types/library-a.ts' does not exist.",
-    "File '/src/node_modules/@types/library-a.tsx' does not exist.",
-    "File '/src/node_modules/@types/library-a.d.ts' does not exist.",
-    "File '/src/node_modules/@types/library-a/package.json' does not exist.",
-    "File '/src/node_modules/@types/library-a/index.ts' does not exist.",
-    "File '/src/node_modules/@types/library-a/index.tsx' does not exist.",
-    "File '/src/node_modules/@types/library-a/index.d.ts' does not exist.",
-    "File '/node_modules/library-a.ts' does not exist.",
-    "File '/node_modules/library-a.tsx' does not exist.",
-    "File '/node_modules/library-a.d.ts' does not exist.",
-    "File '/node_modules/library-a/package.json' does not exist.",
-    "File '/node_modules/library-a/index.ts' does not exist.",
-    "File '/node_modules/library-a/index.tsx' does not exist.",
-    "File '/node_modules/library-a/index.d.ts' does not exist.",
-    "File '/node_modules/@types/library-a.ts' does not exist.",
-    "File '/node_modules/@types/library-a.tsx' does not exist.",
-    "File '/node_modules/@types/library-a.d.ts' does not exist.",
-    "File '/node_modules/@types/library-a/package.json' does not exist.",
-    "File '/node_modules/@types/library-a/index.ts' does not exist.",
-    "File '/node_modules/@types/library-a/index.tsx' does not exist.",
-    "File '/node_modules/@types/library-a/index.d.ts' does not exist.",
-    "Loading module 'library-a' from 'node_modules' folder.",
-    "File '/src/library-b/node_modules/library-a.js' does not exist.",
-    "File '/src/library-b/node_modules/library-a.jsx' does not exist.",
-    "File '/src/library-b/node_modules/library-a/package.json' does not exist.",
-    "File '/src/library-b/node_modules/library-a/index.js' does not exist.",
-    "File '/src/library-b/node_modules/library-a/index.jsx' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a.js' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a.jsx' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a/package.json' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a/index.js' does not exist.",
-    "File '/src/library-b/node_modules/@types/library-a/index.jsx' does not exist.",
-    "File '/src/node_modules/library-a.js' does not exist.",
-    "File '/src/node_modules/library-a.jsx' does not exist.",
-    "File '/src/node_modules/library-a/package.json' does not exist.",
-    "File '/src/node_modules/library-a/index.js' does not exist.",
-    "File '/src/node_modules/library-a/index.jsx' does not exist.",
-    "File '/src/node_modules/@types/library-a.js' does not exist.",
-    "File '/src/node_modules/@types/library-a.jsx' does not exist.",
-    "File '/src/node_modules/@types/library-a/package.json' does not exist.",
-    "File '/src/node_modules/@types/library-a/index.js' does not exist.",
-    "File '/src/node_modules/@types/library-a/index.jsx' does not exist.",
-    "File '/node_modules/library-a.js' does not exist.",
-    "File '/node_modules/library-a.jsx' does not exist.",
-    "File '/node_modules/library-a/package.json' does not exist.",
-    "File '/node_modules/library-a/index.js' does not exist.",
-    "File '/node_modules/library-a/index.jsx' does not exist.",
-    "File '/node_modules/@types/library-a.js' does not exist.",
-    "File '/node_modules/@types/library-a.jsx' does not exist.",
-    "File '/node_modules/@types/library-a/package.json' does not exist.",
-    "File '/node_modules/@types/library-a/index.js' does not exist.",
-    "File '/node_modules/@types/library-a/index.jsx' does not exist.",
-    "======== Module name 'library-a' was not resolved. ========"
+    "File '/src/library-b/node_modules/library-a/index.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/src/library-b/node_modules/library-a/index.ts', result '/src/library-a/index.ts'",
+    "======== Module name 'library-a' was successfully resolved to '/src/library-a/index.ts'. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithSymlinks.types b/tests/baselines/reference/moduleResolutionWithSymlinks.types
new file mode 100644
index 0000000000000..3c0ccd168dd0d
--- /dev/null
+++ b/tests/baselines/reference/moduleResolutionWithSymlinks.types
@@ -0,0 +1,39 @@
+=== /src/app.ts ===
+import { MyClass } from "./library-a";
+>MyClass : typeof MyClass
+
+import { MyClass2 } from "./library-b";
+>MyClass2 : typeof MyClass
+
+let x: MyClass;
+>x : MyClass
+>MyClass : MyClass
+
+let y: MyClass2;
+>y : MyClass
+>MyClass2 : MyClass
+
+x = y;
+>x = y : MyClass
+>x : MyClass
+>y : MyClass
+
+y = x;
+>y = x : MyClass
+>y : MyClass
+>x : MyClass
+
+=== /src/library-a/index.ts ===
+
+export class MyClass { private x: number; }
+>MyClass : MyClass
+>x : number
+
+=== /src/library-b/index.ts ===
+import {MyClass} from "library-a";
+>MyClass : typeof MyClass
+
+export { MyClass as MyClass2 }
+>MyClass : typeof MyClass
+>MyClass2 : typeof MyClass
+
diff --git a/tests/cases/compiler/moduleResolutionWithSymlinks.ts b/tests/cases/compiler/moduleResolutionWithSymlinks.ts
index 8f6f1ca1fbd27..4819b68ffc66d 100644
--- a/tests/cases/compiler/moduleResolutionWithSymlinks.ts
+++ b/tests/cases/compiler/moduleResolutionWithSymlinks.ts
@@ -4,7 +4,7 @@
 
 // @filename: /src/library-a/index.ts
 // @symlink: /src/library-b/node_modules/library-a/index.ts
-export class MyClass{}
+export class MyClass { private x: number; }
 
 // @filename: /src/library-b/index.ts
 import {MyClass} from "library-a";

From ebebac9c4e60fde895f82c18bf18741a82a49a5d Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Mon, 31 Oct 2016 11:08:09 -0700
Subject: [PATCH 129/224] Add helper function

---
 src/harness/harness.ts | 29 ++++++++++++-----------------
 1 file changed, 12 insertions(+), 17 deletions(-)

diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index add3046abc21e..a6e1ffad7f71e 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -1037,21 +1037,7 @@ namespace Harness {
                     if (path[path.length - 1] === "/") {
                         path = <ts.Path>path.substr(0, path.length - 1);
                     }
-
-                    let exists = false;
-                    fileMap.forEachValue(fileName => {
-                        if (!exists && pathStartsWithDirectory(fileName, path)) {
-                            exists = true;
-                        }
-                    });
-                    if (!exists && realPathMap) {
-                        realPathMap.forEachValue(fileName => {
-                            if (!exists && pathStartsWithDirectory(fileName, path)) {
-                                exists = true;
-                            }
-                        });
-                    }
-                    return exists;
+                    return mapHasFileInDirectory(path, fileMap) || mapHasFileInDirectory(path, realPathMap);
                 },
                 getDirectories: d => {
                     const path = ts.toPath(d, currentDirectory, getCanonicalFileName);
@@ -1072,8 +1058,17 @@ namespace Harness {
             };
         }
 
-        function pathStartsWithDirectory(fileName: string, directory: string) {
-            return ts.startsWith(fileName, directory) && fileName[directory.length] === "/";
+        function mapHasFileInDirectory(directoryPath: ts.Path, map: ts.FileMap<any>): boolean {
+            if (!map) {
+                return false;
+            }
+            let exists = false;
+            map.forEachValue(fileName => {
+                if (!exists && ts.startsWith(fileName, directoryPath) && fileName[directoryPath.length] === "/") {
+                    exists = true;
+                }
+            });
+            return exists;
         }
 
         interface HarnessOptions {

From 8984e43b205bfb61335902522b5292f6dcbac093 Mon Sep 17 00:00:00 2001
From: Mohamed Hegazy <mhegazy@microsoft.com>
Date: Mon, 31 Oct 2016 13:15:46 -0700
Subject: [PATCH 130/224] Update generated files (#11963)

---
 src/lib/dom.generated.d.ts       | 28 ++++++++++++++++------------
 src/lib/webworker.generated.d.ts |  6 ++++--
 2 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/src/lib/dom.generated.d.ts b/src/lib/dom.generated.d.ts
index b520b18ea1dac..9a87020d4f0db 100644
--- a/src/lib/dom.generated.d.ts
+++ b/src/lib/dom.generated.d.ts
@@ -1679,6 +1679,7 @@ interface CSSStyleDeclaration {
     writingMode: string | null;
     zIndex: string | null;
     zoom: string | null;
+    resize: string | null;
     getPropertyPriority(propertyName: string): string;
     getPropertyValue(propertyName: string): string;
     item(index: number): string;
@@ -1748,6 +1749,7 @@ declare var CanvasGradient: {
 }
 
 interface CanvasPattern {
+    setTransform(matrix: SVGMatrix): void;
 }
 
 declare var CanvasPattern: {
@@ -2173,7 +2175,7 @@ interface DataTransfer {
     effectAllowed: string;
     readonly files: FileList;
     readonly items: DataTransferItemList;
-    readonly types: DOMStringList;
+    readonly types: string[];
     clearData(format?: string): boolean;
     getData(format: string): string;
     setData(format: string, data: string): boolean;
@@ -7584,7 +7586,7 @@ declare var IDBCursorWithValue: {
 
 interface IDBDatabase extends EventTarget {
     readonly name: string;
-    readonly objectStoreNames: DOMStringList;
+    readonly objectStoreNames: string[];
     onabort: (this: this, ev: Event) => any;
     onerror: (this: this, ev: ErrorEvent) => any;
     version: number;
@@ -7650,7 +7652,7 @@ declare var IDBKeyRange: {
 }
 
 interface IDBObjectStore {
-    readonly indexNames: DOMStringList;
+    readonly indexNames: string[];
     keyPath: string | string[];
     readonly name: string;
     readonly transaction: IDBTransaction;
@@ -8602,7 +8604,7 @@ interface MouseEvent extends UIEvent {
     readonly x: number;
     readonly y: number;
     getModifierState(keyArg: string): boolean;
-    initMouseEvent(typeArg: string, canBubbleArg: boolean, cancelableArg: boolean, viewArg: Window, detailArg: number, screenXArg: number, screenYArg: number, clientXArg: number, clientYArg: number, ctrlKeyArg: boolean, altKeyArg: boolean, shiftKeyArg: boolean, metaKeyArg: boolean, buttonArg: number, relatedTargetArg: EventTarget): void;
+    initMouseEvent(typeArg: string, canBubbleArg: boolean, cancelableArg: boolean, viewArg: Window, detailArg: number, screenXArg: number, screenYArg: number, clientXArg: number, clientYArg: number, ctrlKeyArg: boolean, altKeyArg: boolean, shiftKeyArg: boolean, metaKeyArg: boolean, buttonArg: number, relatedTargetArg: EventTarget | null): void;
 }
 
 declare var MouseEvent: {
@@ -8715,6 +8717,7 @@ interface Navigator extends Object, NavigatorID, NavigatorOnLine, NavigatorConte
     readonly plugins: PluginArray;
     readonly pointerEnabled: boolean;
     readonly webdriver: boolean;
+    readonly hardwareConcurrency: number;
     getGamepads(): Gamepad[];
     javaEnabled(): boolean;
     msLaunchUri(uri: string, successCallback?: MSLaunchUriCallback, noHandlerCallback?: MSLaunchUriCallback): void;
@@ -8732,18 +8735,18 @@ interface Node extends EventTarget {
     readonly attributes: NamedNodeMap;
     readonly baseURI: string | null;
     readonly childNodes: NodeList;
-    readonly firstChild: Node;
-    readonly lastChild: Node;
+    readonly firstChild: Node | null;
+    readonly lastChild: Node | null;
     readonly localName: string | null;
     readonly namespaceURI: string | null;
-    readonly nextSibling: Node;
+    readonly nextSibling: Node | null;
     readonly nodeName: string;
     readonly nodeType: number;
     nodeValue: string | null;
     readonly ownerDocument: Document;
-    readonly parentElement: HTMLElement;
-    readonly parentNode: Node;
-    readonly previousSibling: Node;
+    readonly parentElement: HTMLElement | null;
+    readonly parentNode: Node | null;
+    readonly previousSibling: Node | null;
     textContent: string | null;
     appendChild(newChild: Node): Node;
     cloneNode(deep?: boolean): Node;
@@ -12853,7 +12856,7 @@ interface Window extends EventTarget, WindowTimers, WindowSessionStorage, Window
     readonly devicePixelRatio: number;
     readonly doNotTrack: string;
     readonly document: Document;
-    event: Event;
+    event: Event | undefined;
     readonly external: External;
     readonly frameElement: Element;
     readonly frames: Window;
@@ -13155,6 +13158,7 @@ interface XMLHttpRequest extends EventTarget, XMLHttpRequestEventTarget {
     readonly upload: XMLHttpRequestUpload;
     withCredentials: boolean;
     msCaching?: string;
+    readonly responseURL: string;
     abort(): void;
     getAllResponseHeaders(): string;
     getResponseHeader(header: string): string | null;
@@ -14301,7 +14305,7 @@ declare var defaultStatus: string;
 declare var devicePixelRatio: number;
 declare var doNotTrack: string;
 declare var document: Document;
-declare var event: Event;
+declare var event: Event | undefined;
 declare var external: External;
 declare var frameElement: Element;
 declare var frames: Window;
diff --git a/src/lib/webworker.generated.d.ts b/src/lib/webworker.generated.d.ts
index b543939ef0a87..4aeba69630671 100644
--- a/src/lib/webworker.generated.d.ts
+++ b/src/lib/webworker.generated.d.ts
@@ -341,7 +341,7 @@ declare var IDBCursorWithValue: {
 
 interface IDBDatabase extends EventTarget {
     readonly name: string;
-    readonly objectStoreNames: DOMStringList;
+    readonly objectStoreNames: string[];
     onabort: (this: this, ev: Event) => any;
     onerror: (this: this, ev: ErrorEvent) => any;
     version: number;
@@ -407,7 +407,7 @@ declare var IDBKeyRange: {
 }
 
 interface IDBObjectStore {
-    readonly indexNames: DOMStringList;
+    readonly indexNames: string[];
     keyPath: string | string[];
     readonly name: string;
     readonly transaction: IDBTransaction;
@@ -740,6 +740,7 @@ interface XMLHttpRequest extends EventTarget, XMLHttpRequestEventTarget {
     readonly upload: XMLHttpRequestUpload;
     withCredentials: boolean;
     msCaching?: string;
+    readonly responseURL: string;
     abort(): void;
     getAllResponseHeaders(): string;
     getResponseHeader(header: string): string | null;
@@ -902,6 +903,7 @@ declare var WorkerLocation: {
 }
 
 interface WorkerNavigator extends Object, NavigatorID, NavigatorOnLine {
+    readonly hardwareConcurrency: number;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
 }
 

From ebef408dfa18061fb3ae984bbc2f0315177d756b Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 31 Oct 2016 14:44:04 -0700
Subject: [PATCH 131/224] Move eitherIsNotLiteral check into switch and ===
 checks

This improves error messages
---
 src/compiler/checker.ts                       | 22 ++++++++++++-------
 tests/baselines/reference/expr.errors.txt     |  8 +++----
 .../for-inStatementsArrayErrors.errors.txt    |  4 ++--
 ...sertionsInEqualityComparisons02.errors.txt |  4 ++--
 .../switchAssignmentCompat.errors.txt         |  4 ++--
 .../switchCaseCircularRefeference.errors.txt  | 10 ++++-----
 ...itchCasesExpressionTypeMismatch.errors.txt | 17 ++++++--------
 .../reference/symbolType9.errors.txt          | 16 +++++++-------
 8 files changed, 43 insertions(+), 42 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index d76d4e1e77018..2d05e16ef825e 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -13814,12 +13814,6 @@ namespace ts {
         }
 
         function isTypeEqualityComparableTo(source: Type, target: Type) {
-            const sourceIsLiteral = isLiteralType(source);
-            const targetIsLiteral = isLiteralType(target);
-            if (!sourceIsLiteral || !targetIsLiteral) {
-                source = sourceIsLiteral ? getBaseTypeOfLiteralType(source) : source;
-                target = targetIsLiteral ? getBaseTypeOfLiteralType(target) : target;
-            }
             return (target.flags & TypeFlags.Nullable) !== 0 || isTypeComparableTo(source, target);
         }
 
@@ -13960,6 +13954,12 @@ namespace ts {
                 case SyntaxKind.ExclamationEqualsToken:
                 case SyntaxKind.EqualsEqualsEqualsToken:
                 case SyntaxKind.ExclamationEqualsEqualsToken:
+                    const leftIsLiteral = isLiteralType(leftType);
+                    const rightIsLiteral = isLiteralType(rightType);
+                    if (!leftIsLiteral || !rightIsLiteral) {
+                        leftType = leftIsLiteral ? getBaseTypeOfLiteralType(leftType) : leftType;
+                        rightType = rightIsLiteral ? getBaseTypeOfLiteralType(rightType) : rightType;
+                    }
                     if (!isTypeEqualityComparableTo(leftType, rightType) && !isTypeEqualityComparableTo(rightType, leftType)) {
                         reportOperatorError();
                     }
@@ -16882,7 +16882,7 @@ namespace ts {
             let firstDefaultClause: CaseOrDefaultClause;
             let hasDuplicateDefaultClause = false;
 
-            const expressionType = checkExpression(node.expression);
+            let expressionType = checkExpression(node.expression);
             forEach(node.caseBlock.clauses, clause => {
                 // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
                 if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -16903,7 +16903,13 @@ namespace ts {
                     // TypeScript 1.0 spec (April 2014): 5.9
                     // In a 'switch' statement, each 'case' expression must be of a type that is comparable
                     // to or from the type of the 'switch' expression.
-                    const caseType = checkExpression(caseClause.expression);
+                    let caseType = checkExpression(caseClause.expression);
+                    const caseIsLiteral = isLiteralType(caseType);
+                    const expressionIsLiteral = isLiteralType(expressionType);
+                    if (!caseIsLiteral || !expressionIsLiteral) {
+                        caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
+                        expressionType = expressionIsLiteral ? getBaseTypeOfLiteralType(expressionType) : expressionType;
+                    }
                     if (!isTypeEqualityComparableTo(expressionType, caseType)) {
                         // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
                         checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
diff --git a/tests/baselines/reference/expr.errors.txt b/tests/baselines/reference/expr.errors.txt
index 52f6f64fef287..23215cac6bae2 100644
--- a/tests/baselines/reference/expr.errors.txt
+++ b/tests/baselines/reference/expr.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/compiler/expr.ts(87,5): error TS2365: Operator '==' cannot be applied to types 'number' and 'string'.
-tests/cases/compiler/expr.ts(88,5): error TS2365: Operator '==' cannot be applied to types 'number' and 'false'.
+tests/cases/compiler/expr.ts(88,5): error TS2365: Operator '==' cannot be applied to types 'number' and 'boolean'.
 tests/cases/compiler/expr.ts(94,5): error TS2365: Operator '==' cannot be applied to types 'string' and 'number'.
-tests/cases/compiler/expr.ts(95,5): error TS2365: Operator '==' cannot be applied to types 'string' and 'false'.
+tests/cases/compiler/expr.ts(95,5): error TS2365: Operator '==' cannot be applied to types 'string' and 'boolean'.
 tests/cases/compiler/expr.ts(98,5): error TS2365: Operator '==' cannot be applied to types 'string' and 'E'.
 tests/cases/compiler/expr.ts(115,5): error TS2365: Operator '==' cannot be applied to types 'E' and 'string'.
 tests/cases/compiler/expr.ts(116,5): error TS2365: Operator '==' cannot be applied to types 'E' and 'false'.
@@ -161,7 +161,7 @@ tests/cases/compiler/expr.ts(242,7): error TS2363: The right-hand side of an ari
 !!! error TS2365: Operator '==' cannot be applied to types 'number' and 'string'.
         n==b;
         ~~~~
-!!! error TS2365: Operator '==' cannot be applied to types 'number' and 'false'.
+!!! error TS2365: Operator '==' cannot be applied to types 'number' and 'boolean'.
         n==i;
         n==n;
         n==e;
@@ -172,7 +172,7 @@ tests/cases/compiler/expr.ts(242,7): error TS2363: The right-hand side of an ari
 !!! error TS2365: Operator '==' cannot be applied to types 'string' and 'number'.
         s==b;
         ~~~~
-!!! error TS2365: Operator '==' cannot be applied to types 'string' and 'false'.
+!!! error TS2365: Operator '==' cannot be applied to types 'string' and 'boolean'.
         s==i;
         s==s;
         s==e;
diff --git a/tests/baselines/reference/for-inStatementsArrayErrors.errors.txt b/tests/baselines/reference/for-inStatementsArrayErrors.errors.txt
index e639d8452de21..6886d992bb2e5 100644
--- a/tests/baselines/reference/for-inStatementsArrayErrors.errors.txt
+++ b/tests/baselines/reference/for-inStatementsArrayErrors.errors.txt
@@ -1,6 +1,6 @@
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(5,14): error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(6,16): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(7,9): error TS2365: Operator '===' cannot be applied to types 'string' and '1'.
+tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(7,9): error TS2365: Operator '===' cannot be applied to types 'string' and 'number'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(9,16): error TS2339: Property 'unknownProperty' does not exist on type 'string'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(13,10): error TS2403: Subsequent variable declarations must have the same type.  Variable 'i' must be of type 'number', but here has type 'string'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(17,10): error TS2403: Subsequent variable declarations must have the same type.  Variable 'j' must be of type 'any', but here has type 'string'.
@@ -19,7 +19,7 @@ tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
         if (x === 1) {
             ~~~~~~~
-!!! error TS2365: Operator '===' cannot be applied to types 'string' and '1'.
+!!! error TS2365: Operator '===' cannot be applied to types 'string' and 'number'.
         }
         let a3 = x.unknownProperty;
                    ~~~~~~~~~~~~~~~
diff --git a/tests/baselines/reference/stringLiteralsAssertionsInEqualityComparisons02.errors.txt b/tests/baselines/reference/stringLiteralsAssertionsInEqualityComparisons02.errors.txt
index 81adf58dbde90..fd92af4e84f63 100644
--- a/tests/baselines/reference/stringLiteralsAssertionsInEqualityComparisons02.errors.txt
+++ b/tests/baselines/reference/stringLiteralsAssertionsInEqualityComparisons02.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/types/literal/stringLiteralsAssertionsInEqualityComparisons02.ts(3,9): error TS2365: Operator '===' cannot be applied to types '"foo"' and '"baz"'.
-tests/cases/conformance/types/literal/stringLiteralsAssertionsInEqualityComparisons02.ts(5,9): error TS2365: Operator '==' cannot be applied to types '"foo"' and 'number'.
+tests/cases/conformance/types/literal/stringLiteralsAssertionsInEqualityComparisons02.ts(5,9): error TS2365: Operator '==' cannot be applied to types 'string' and 'number'.
 tests/cases/conformance/types/literal/stringLiteralsAssertionsInEqualityComparisons02.ts(5,19): error TS2352: Type 'string' cannot be converted to type 'number'.
 
 
@@ -12,7 +12,7 @@ tests/cases/conformance/types/literal/stringLiteralsAssertionsInEqualityComparis
     var b = "foo" !== ("bar" as "foo");
     var c = "foo" == (<number>"bar");
             ~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2365: Operator '==' cannot be applied to types '"foo"' and 'number'.
+!!! error TS2365: Operator '==' cannot be applied to types 'string' and 'number'.
                       ~~~~~~~~~~~~~
 !!! error TS2352: Type 'string' cannot be converted to type 'number'.
     var d = "foo" === ("bar" as EnhancedString);
\ No newline at end of file
diff --git a/tests/baselines/reference/switchAssignmentCompat.errors.txt b/tests/baselines/reference/switchAssignmentCompat.errors.txt
index 46c89fa5b52d2..747a1035b6846 100644
--- a/tests/baselines/reference/switchAssignmentCompat.errors.txt
+++ b/tests/baselines/reference/switchAssignmentCompat.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
 
 
 ==== tests/cases/compiler/switchAssignmentCompat.ts (1 errors) ====
@@ -7,6 +7,6 @@ tests/cases/compiler/switchAssignmentCompat.ts(4,10): error TS2678: Type 'typeof
     switch (0) {
         case Foo: break; // Error expected
              ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
     }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/switchCaseCircularRefeference.errors.txt b/tests/baselines/reference/switchCaseCircularRefeference.errors.txt
index 9ee571de468ce..bc576f8e723b8 100644
--- a/tests/baselines/reference/switchCaseCircularRefeference.errors.txt
+++ b/tests/baselines/reference/switchCaseCircularRefeference.errors.txt
@@ -1,6 +1,5 @@
-tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-  Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-    Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+  Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
 
 
 ==== tests/cases/compiler/switchCaseCircularRefeference.ts (1 errors) ====
@@ -10,9 +9,8 @@ tests/cases/compiler/switchCaseCircularRefeference.ts(5,10): error TS2678: Type
         switch (x.a) {
         case x:
              ~
-!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678:   Type '{ a: "C"; e: any; }' is not comparable to type '"A" | "C"'.
-!!! error TS2678:     Type '{ a: "C"; e: any; }' is not comparable to type '"C"'.
+!!! error TS2678: Type '{ a: "A"; b: any; } | { a: "C"; e: any; }' is not comparable to type 'string'.
+!!! error TS2678:   Type '{ a: "C"; e: any; }' is not comparable to type 'string'.
             break;
         }
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt b/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt
index 3ea12e2460f65..26d39efef48ec 100644
--- a/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt
+++ b/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt
@@ -1,25 +1,22 @@
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type '0'.
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type '"sss"' is not comparable to type '0'.
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(6,10): error TS2678: Type '123' is not comparable to type '0'.
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'true' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type 'string' is not comparable to type 'number'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'boolean' is not comparable to type 'number'.
 
 
-==== tests/cases/compiler/switchCasesExpressionTypeMismatch.ts (4 errors) ====
+==== tests/cases/compiler/switchCasesExpressionTypeMismatch.ts (3 errors) ====
     class Foo { }
     
     switch (0) {
         case Foo: break;    // Error
              ~~~
-!!! error TS2678: Type 'typeof Foo' is not comparable to type '0'.
+!!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
         case "sss": break;  // Error
              ~~~~~
-!!! error TS2678: Type '"sss"' is not comparable to type '0'.
+!!! error TS2678: Type 'string' is not comparable to type 'number'.
         case 123: break;    // No Error
-             ~~~
-!!! error TS2678: Type '123' is not comparable to type '0'.
         case true: break;   // Error
              ~~~~
-!!! error TS2678: Type 'true' is not comparable to type '0'.
+!!! error TS2678: Type 'boolean' is not comparable to type 'number'.
     }
     
     var s: any = 0;
diff --git a/tests/baselines/reference/symbolType9.errors.txt b/tests/baselines/reference/symbolType9.errors.txt
index 55a766a379e80..5506fdc6f9dac 100644
--- a/tests/baselines/reference/symbolType9.errors.txt
+++ b/tests/baselines/reference/symbolType9.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/conformance/es6/Symbols/symbolType9.ts(3,1): error TS2365: Operator '==' cannot be applied to types 'symbol' and 'true'.
-tests/cases/conformance/es6/Symbols/symbolType9.ts(5,1): error TS2365: Operator '!=' cannot be applied to types '0' and 'symbol'.
-tests/cases/conformance/es6/Symbols/symbolType9.ts(7,1): error TS2365: Operator '===' cannot be applied to types 'symbol' and '1'.
-tests/cases/conformance/es6/Symbols/symbolType9.ts(9,1): error TS2365: Operator '!==' cannot be applied to types 'false' and 'symbol'.
+tests/cases/conformance/es6/Symbols/symbolType9.ts(3,1): error TS2365: Operator '==' cannot be applied to types 'symbol' and 'boolean'.
+tests/cases/conformance/es6/Symbols/symbolType9.ts(5,1): error TS2365: Operator '!=' cannot be applied to types 'number' and 'symbol'.
+tests/cases/conformance/es6/Symbols/symbolType9.ts(7,1): error TS2365: Operator '===' cannot be applied to types 'symbol' and 'number'.
+tests/cases/conformance/es6/Symbols/symbolType9.ts(9,1): error TS2365: Operator '!==' cannot be applied to types 'boolean' and 'symbol'.
 
 
 ==== tests/cases/conformance/es6/Symbols/symbolType9.ts (4 errors) ====
@@ -9,16 +9,16 @@ tests/cases/conformance/es6/Symbols/symbolType9.ts(9,1): error TS2365: Operator
     s == s;
     s == true;
     ~~~~~~~~~
-!!! error TS2365: Operator '==' cannot be applied to types 'symbol' and 'true'.
+!!! error TS2365: Operator '==' cannot be applied to types 'symbol' and 'boolean'.
     s != s;
     0 != s;
     ~~~~~~
-!!! error TS2365: Operator '!=' cannot be applied to types '0' and 'symbol'.
+!!! error TS2365: Operator '!=' cannot be applied to types 'number' and 'symbol'.
     s === s;
     s === 1;
     ~~~~~~~
-!!! error TS2365: Operator '===' cannot be applied to types 'symbol' and '1'.
+!!! error TS2365: Operator '===' cannot be applied to types 'symbol' and 'number'.
     s !== s;
     false !== s;
     ~~~~~~~~~~~
-!!! error TS2365: Operator '!==' cannot be applied to types 'false' and 'symbol'.
\ No newline at end of file
+!!! error TS2365: Operator '!==' cannot be applied to types 'boolean' and 'symbol'.
\ No newline at end of file

From ecb7b00e1c98d54e42bd675ad4c25d8c7cb2f5b7 Mon Sep 17 00:00:00 2001
From: Andy <anhans@microsoft.com>
Date: Mon, 31 Oct 2016 15:04:22 -0700
Subject: [PATCH 132/224] Forbid augmentation of untyped module (#11962)

* Forbid augmentation of untyped module

* Just use `undefined` for untyped modules
---
 src/compiler/checker.ts                       | 47 +++++++++----------
 src/compiler/diagnosticMessages.json          |  4 ++
 src/compiler/utilities.ts                     |  4 +-
 ...edModuleImport_withAugmentation.errors.txt | 17 +++++++
 .../untypedModuleImport_withAugmentation.js   | 19 ++++++++
 .../untypedModuleImport_withAugmentation.ts   | 13 +++++
 tests/cases/fourslash/untypedModuleImport.ts  |  2 +-
 7 files changed, 77 insertions(+), 29 deletions(-)
 create mode 100644 tests/baselines/reference/untypedModuleImport_withAugmentation.errors.txt
 create mode 100644 tests/baselines/reference/untypedModuleImport_withAugmentation.js
 create mode 100644 tests/cases/conformance/moduleResolution/untypedModuleImport_withAugmentation.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 704018627b24e..37ace5741a174 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -498,7 +498,7 @@ namespace ts {
                 const moduleNotFoundError = !isInAmbientContext(moduleName.parent.parent)
                     ? Diagnostics.Invalid_module_name_in_augmentation_module_0_cannot_be_found
                     : undefined;
-                let mainModule = resolveExternalModuleNameWorker(moduleName, moduleName, moduleNotFoundError);
+                let mainModule = resolveExternalModuleNameWorker(moduleName, moduleName, moduleNotFoundError, /*isForAugmentation*/ true);
                 if (!mainModule) {
                     return;
                 }
@@ -1074,7 +1074,7 @@ namespace ts {
             const moduleSymbol = resolveExternalModuleName(node, (<ImportDeclaration>node.parent).moduleSpecifier);
 
             if (moduleSymbol) {
-                const exportDefaultSymbol = isUntypedModuleSymbol(moduleSymbol) ?
+                const exportDefaultSymbol = isShorthandAmbientModuleSymbol(moduleSymbol) ?
                     moduleSymbol :
                     moduleSymbol.exports["export="] ?
                         getPropertyOfType(getTypeOfSymbol(moduleSymbol.exports["export="]), "default") :
@@ -1150,7 +1150,7 @@ namespace ts {
             if (targetSymbol) {
                 const name = specifier.propertyName || specifier.name;
                 if (name.text) {
-                    if (isUntypedModuleSymbol(moduleSymbol)) {
+                    if (isShorthandAmbientModuleSymbol(moduleSymbol)) {
                         return moduleSymbol;
                     }
 
@@ -1351,16 +1351,16 @@ namespace ts {
             return resolveExternalModuleNameWorker(location, moduleReferenceExpression, Diagnostics.Cannot_find_module_0);
         }
 
-        function resolveExternalModuleNameWorker(location: Node, moduleReferenceExpression: Expression, moduleNotFoundError: DiagnosticMessage): Symbol {
+        function resolveExternalModuleNameWorker(location: Node, moduleReferenceExpression: Expression, moduleNotFoundError: DiagnosticMessage, isForAugmentation = false): Symbol {
             if (moduleReferenceExpression.kind !== SyntaxKind.StringLiteral) {
                 return;
             }
 
             const moduleReferenceLiteral = <LiteralExpression>moduleReferenceExpression;
-            return resolveExternalModule(location, moduleReferenceLiteral.text, moduleNotFoundError, moduleReferenceLiteral);
+            return resolveExternalModule(location, moduleReferenceLiteral.text, moduleNotFoundError, moduleReferenceLiteral, isForAugmentation);
         }
 
-        function resolveExternalModule(location: Node, moduleReference: string, moduleNotFoundError: DiagnosticMessage, errorNode: Node): Symbol {
+        function resolveExternalModule(location: Node, moduleReference: string, moduleNotFoundError: DiagnosticMessage, errorNode: Node, isForAugmentation = false): Symbol {
             // Module names are escaped in our symbol table.  However, string literal values aren't.
             // Escape the name in the "require(...)" clause to ensure we find the right symbol.
             const moduleName = escapeIdentifier(moduleReference);
@@ -1403,24 +1403,19 @@ namespace ts {
 
              // May be an untyped module. If so, ignore resolutionDiagnostic.
             if (!isRelative && resolvedModule && !extensionIsTypeScript(resolvedModule.extension)) {
-                if (compilerOptions.noImplicitAny) {
-                    if (moduleNotFoundError) {
-                        error(errorNode,
-                            Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type,
-                            moduleReference,
-                            resolvedModule.resolvedFileName);
-                    }
-                    return undefined;
-                }
-
-                // Create a new symbol to represent the untyped module and store it in globals.
-                // This provides a name to the module. See the test tests/cases/fourslash/untypedModuleImport.ts
-                const newSymbol = createSymbol(SymbolFlags.ValueModule, quotedName);
-                // Module symbols are expected to have 'exports', although since this is an untyped module it can be empty.
-                newSymbol.exports = createMap<Symbol>();
-                // Cache it so subsequent accesses will return the same module.
-                globals[quotedName] = newSymbol;
-                return newSymbol;
+                if (isForAugmentation) {
+                    Debug.assert(!!moduleNotFoundError);
+                    const diag = Diagnostics.Invalid_module_name_in_augmentation_Module_0_resolves_to_an_untyped_module_at_1_which_cannot_be_augmented;
+                    error(errorNode, diag, moduleName, resolvedModule.resolvedFileName);
+                }
+                else if (compilerOptions.noImplicitAny && moduleNotFoundError) {
+                    error(errorNode,
+                        Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type,
+                        moduleReference,
+                        resolvedModule.resolvedFileName);
+                }
+                // Failed imports and untyped modules are both treated in an untyped manner; only difference is whether we give a diagnostic first.
+                return undefined;
             }
 
             if (moduleNotFoundError) {
@@ -3490,7 +3485,7 @@ namespace ts {
         function getTypeOfFuncClassEnumModule(symbol: Symbol): Type {
             const links = getSymbolLinks(symbol);
             if (!links.type) {
-                if (symbol.flags & SymbolFlags.Module && isUntypedModuleSymbol(symbol)) {
+                if (symbol.flags & SymbolFlags.Module && isShorthandAmbientModuleSymbol(symbol)) {
                     links.type = anyType;
                 }
                 else {
@@ -19063,7 +19058,7 @@ namespace ts {
 
         function moduleExportsSomeValue(moduleReferenceExpression: Expression): boolean {
             let moduleSymbol = resolveExternalModuleName(moduleReferenceExpression.parent, moduleReferenceExpression);
-            if (!moduleSymbol || isUntypedModuleSymbol(moduleSymbol)) {
+            if (!moduleSymbol || isShorthandAmbientModuleSymbol(moduleSymbol)) {
                 // If the module is not found or is shorthand, assume that it may export a value.
                 return true;
             }
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index e2a2a4b9a0cf4..ef3de5b353cc7 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1839,6 +1839,10 @@
         "category": "Error",
         "code": 2664
     },
+    "Invalid module name in augmentation. Module '{0}' resolves to an untyped module at '{1}', which cannot be augmented.": {
+        "category": "Error",
+        "code": 2665
+    },
     "Exports and export assignments are not permitted in module augmentations.": {
         "category": "Error",
         "code": 2666
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index f86a87e19eef4..9274d20f76e84 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -403,8 +403,8 @@ namespace ts {
     }
 
     /** Given a symbol for a module, checks that it is either an untyped import or a shorthand ambient module. */
-    export function isUntypedModuleSymbol(moduleSymbol: Symbol): boolean {
-        return !moduleSymbol.valueDeclaration || isShorthandAmbientModule(moduleSymbol.valueDeclaration);
+    export function isShorthandAmbientModuleSymbol(moduleSymbol: Symbol): boolean {
+        return isShorthandAmbientModule(moduleSymbol.valueDeclaration);
     }
 
     function isShorthandAmbientModule(node: Node): boolean {
diff --git a/tests/baselines/reference/untypedModuleImport_withAugmentation.errors.txt b/tests/baselines/reference/untypedModuleImport_withAugmentation.errors.txt
new file mode 100644
index 0000000000000..290cfbc6cbd85
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport_withAugmentation.errors.txt
@@ -0,0 +1,17 @@
+/a.ts(1,16): error TS2665: Invalid module name in augmentation. Module 'foo' resolves to an untyped module at '/node_modules/foo/index.js', which cannot be augmented.
+
+
+==== /a.ts (1 errors) ====
+    declare module "foo" {
+                   ~~~~~
+!!! error TS2665: Invalid module name in augmentation. Module 'foo' resolves to an untyped module at '/node_modules/foo/index.js', which cannot be augmented.
+        export const x: number;
+    }
+    import { x } from "foo";
+    x;
+    
+==== /node_modules/foo/index.js (0 errors) ====
+    // This tests that augmenting an untyped module is forbidden.
+    
+    This file is not processed.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/untypedModuleImport_withAugmentation.js b/tests/baselines/reference/untypedModuleImport_withAugmentation.js
new file mode 100644
index 0000000000000..17eda95aa8af7
--- /dev/null
+++ b/tests/baselines/reference/untypedModuleImport_withAugmentation.js
@@ -0,0 +1,19 @@
+//// [tests/cases/conformance/moduleResolution/untypedModuleImport_withAugmentation.ts] ////
+
+//// [index.js]
+// This tests that augmenting an untyped module is forbidden.
+
+This file is not processed.
+
+//// [a.ts]
+declare module "foo" {
+    export const x: number;
+}
+import { x } from "foo";
+x;
+
+
+//// [a.js]
+"use strict";
+var foo_1 = require("foo");
+foo_1.x;
diff --git a/tests/cases/conformance/moduleResolution/untypedModuleImport_withAugmentation.ts b/tests/cases/conformance/moduleResolution/untypedModuleImport_withAugmentation.ts
new file mode 100644
index 0000000000000..e27c1232d2587
--- /dev/null
+++ b/tests/cases/conformance/moduleResolution/untypedModuleImport_withAugmentation.ts
@@ -0,0 +1,13 @@
+// @noImplicitReferences: true
+// @currentDirectory: /
+// This tests that augmenting an untyped module is forbidden.
+
+// @filename: /node_modules/foo/index.js
+This file is not processed.
+
+// @filename: /a.ts
+declare module "foo" {
+    export const x: number;
+}
+import { x } from "foo";
+x;
diff --git a/tests/cases/fourslash/untypedModuleImport.ts b/tests/cases/fourslash/untypedModuleImport.ts
index 3fd209d480d31..d128ad24ea3da 100644
--- a/tests/cases/fourslash/untypedModuleImport.ts
+++ b/tests/cases/fourslash/untypedModuleImport.ts
@@ -13,7 +13,7 @@ verify.numberOfErrorsInCurrentFile(0);
 
 goTo.marker("fooModule");
 verify.goToDefinitionIs([]);
-verify.quickInfoIs('module "foo"');
+verify.quickInfoIs("");
 verify.referencesAre([])
 
 goTo.marker("foo");

From f9e208533ad4d87509091a67c4dc5c1bfb85a446 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 31 Oct 2016 15:28:28 -0700
Subject: [PATCH 133/224] Unify checking of indexed access expressions and
 indexed access types

---
 src/compiler/checker.ts              | 220 +++++++++------------------
 src/compiler/diagnosticMessages.json |  22 +--
 2 files changed, 79 insertions(+), 163 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 0e7e255953fa1..fc89bfd764ca5 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5709,44 +5709,61 @@ namespace ts {
             return indexedAccessTypes[objectType.id] || (indexedAccessTypes[objectType.id] = createIndexedAccessType(objectType, indexType));
         }
 
-        function getPropertyTypeForIndexType(objectType: Type, indexType: Type, errorNode?: Node) {
+        function getPropertyTypeForIndexType(objectType: Type, indexType: Type, accessNode?: ElementAccessExpression | IndexedAccessTypeNode) {
+            const accessExpression = accessNode && accessNode.kind === SyntaxKind.ElementAccessExpression ? <ElementAccessExpression>accessNode : undefined;
             if (indexType.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral | TypeFlags.EnumLiteral)) {
-                const propType = getTypeOfPropertyOfType(objectType, escapeIdentifier((<LiteralType>indexType).text));
-                if (propType) {
-                    return propType;
+                const prop = getPropertyOfType(objectType, escapeIdentifier((<LiteralType>indexType).text));
+                if (prop) {
+                    if (accessExpression && isAssignmentTarget(accessExpression) && isReadonlySymbol(prop)) {
+                        error(accessExpression.argumentExpression, Diagnostics.Cannot_assign_to_0_because_it_is_a_constant_or_a_read_only_property, symbolToString(prop));
+                        return unknownType;
+                    }
+                    return getTypeOfSymbol(prop);
                 }
             }
-            if (isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.NumberLike)) {
-                const numberIndexType = getIndexTypeOfType(objectType, IndexKind.Number);
-                if (numberIndexType) {
-                    return numberIndexType;
+            if (isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.ESSymbol)) {
+                const indexInfo = isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.NumberLike) && getIndexInfoOfType(objectType, IndexKind.Number) ||
+                    getIndexInfoOfType(objectType, IndexKind.String) ||
+                    undefined;
+                if (indexInfo) {
+                    if (accessExpression && isAssignmentTarget(accessExpression) && indexInfo.isReadonly) {
+                        error(accessExpression, Diagnostics.Index_signature_in_type_0_only_permits_reading, typeToString(objectType));
+                        return unknownType;
+                    }
+                    return indexInfo.type;
                 }
-            }
-            if (isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.StringLike | TypeFlags.NumberLike)) {
-                const stringIndexType = getIndexTypeOfType(objectType, IndexKind.String);
-                if (stringIndexType) {
-                    return stringIndexType;
+                if (accessExpression && !isConstEnumObjectType(objectType)) {
+                    if (compilerOptions.noImplicitAny && !compilerOptions.suppressImplicitAnyIndexErrors && !isTypeAny(objectType)) {
+                        if (getIndexTypeOfType(objectType, IndexKind.Number)) {
+                            error(accessExpression.argumentExpression, Diagnostics.Element_implicitly_has_an_any_type_because_index_expression_is_not_of_type_number);
+                        }
+                        else {
+                            error(accessExpression, Diagnostics.Element_implicitly_has_an_any_type_because_type_0_has_no_index_signature, typeToString(objectType));
+                        }
+                    }
+                    return anyType;
                 }
             }
-            if (errorNode) {
+            if (accessNode) {
+                const indexNode = accessNode.kind === SyntaxKind.ElementAccessExpression ? (<ElementAccessExpression>accessNode).argumentExpression : (<IndexedAccessTypeNode>accessNode).indexType;
                 if (indexType.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) {
-                    error(errorNode, Diagnostics.Property_0_does_not_exist_on_type_1, (<LiteralType>indexType).text, typeToString(objectType));
+                    error(indexNode, Diagnostics.Property_0_does_not_exist_on_type_1, (<LiteralType>indexType).text, typeToString(objectType));
                 }
                 else if (indexType.flags & (TypeFlags.String | TypeFlags.Number)) {
-                    error(errorNode, Diagnostics.Type_0_has_no_matching_index_signature_for_type_1, typeToString(objectType), typeToString(indexType));
+                    error(accessNode, Diagnostics.Type_0_has_no_matching_index_signature_for_type_1, typeToString(objectType), typeToString(indexType));
                 }
                 else {
-                    error(errorNode, Diagnostics.Type_0_cannot_be_used_as_an_index_type, typeToString(indexType));
+                    error(indexNode, Diagnostics.Type_0_cannot_be_used_as_an_index_type, typeToString(indexType));
                 }
             }
             return unknownType;
         }
 
-        function getIndexedAccessType(objectType: Type, indexType: Type, errorNode?: Node) {
+        function getIndexedAccessType(objectType: Type, indexType: Type, accessNode?: ElementAccessExpression | IndexedAccessTypeNode) {
             if (indexType.flags & TypeFlags.TypeParameter) {
                 if (!isTypeAssignableTo(getConstraintOfTypeParameter(<TypeParameter>indexType) || emptyObjectType, getIndexType(objectType))) {
-                    if (errorNode) {
-                        error(errorNode, Diagnostics.Type_0_is_not_constrained_to_keyof_1, typeToString(indexType), typeToString(objectType));
+                    if (accessNode) {
+                        error(accessNode, Diagnostics.Type_0_is_not_constrained_to_keyof_1, typeToString(indexType), typeToString(objectType));
                     }
                     return unknownType;
                 }
@@ -5755,7 +5772,7 @@ namespace ts {
             if (indexType.flags & TypeFlags.Union && !(indexType.flags & TypeFlags.Primitive)) {
                 const propTypes: Type[] = [];
                 for (const t of (<UnionType>indexType).types) {
-                    const propType = getPropertyTypeForIndexType(objectType, t, errorNode);
+                    const propType = getPropertyTypeForIndexType(objectType, t, accessNode);
                     if (propType === unknownType) {
                         return unknownType;
                     }
@@ -5763,14 +5780,13 @@ namespace ts {
                 }
                 return getUnionType(propTypes);
             }
-            return getPropertyTypeForIndexType(objectType, indexType, errorNode);
+            return getPropertyTypeForIndexType(objectType, indexType, accessNode);
         }
 
         function getTypeFromIndexedAccessTypeNode(node: IndexedAccessTypeNode) {
             const links = getNodeLinks(node);
             if (!links.resolvedType) {
-                links.resolvedType = getIndexedAccessType(getTypeFromTypeNodeNoAlias(node.objectType),
-                    getTypeFromTypeNodeNoAlias(node.indexType), node.indexType);
+                links.resolvedType = getIndexedAccessType(getTypeFromTypeNodeNoAlias(node.objectType), getTypeFromTypeNodeNoAlias(node.indexType), node);
             }
             return links.resolvedType;
         }
@@ -11546,8 +11562,10 @@ namespace ts {
         }
 
         function checkIndexedAccess(node: ElementAccessExpression): Type {
-            // Grammar checking
-            if (!node.argumentExpression) {
+            const objectType = checkNonNullExpression(node.expression);
+
+            const indexExpression = node.argumentExpression;
+            if (!indexExpression) {
                 const sourceFile = getSourceFileOfNode(node);
                 if (node.parent.kind === SyntaxKind.NewExpression && (<NewExpression>node.parent).expression === node) {
                     const start = skipTrivia(sourceFile.text, node.expression.end);
@@ -11559,87 +11577,36 @@ namespace ts {
                     const end = node.end;
                     grammarErrorAtPos(sourceFile, start, end - start, Diagnostics.Expression_expected);
                 }
+                return unknownType;
             }
 
-            let objectType = checkNonNullExpression(node.expression);
-            const indexType = node.argumentExpression ? checkExpression(node.argumentExpression) : unknownType;
+            const indexType = isForInVariableForNumericPropertyNames(indexExpression) ? numberType : checkExpression(indexExpression);
 
             if (objectType === unknownType || objectType === silentNeverType) {
                 return objectType;
             }
 
-            if (indexType.flags & TypeFlags.TypeParameter) {
-                return getIndexedAccessType(objectType, indexType, node.argumentExpression);
-            }
-
-            objectType = getApparentType(objectType);
-
-            const isConstEnum = isConstEnumObjectType(objectType);
-            if (isConstEnum &&
-                (!node.argumentExpression || node.argumentExpression.kind !== SyntaxKind.StringLiteral)) {
-                error(node.argumentExpression, Diagnostics.A_const_enum_member_can_only_be_accessed_using_a_string_literal);
+            if (isConstEnumObjectType(objectType) && indexExpression.kind !== SyntaxKind.StringLiteral) {
+                error(indexExpression, Diagnostics.A_const_enum_member_can_only_be_accessed_using_a_string_literal);
                 return unknownType;
             }
 
-            // TypeScript 1.0 spec (April 2014): 4.10 Property Access
-            // - If IndexExpr is a string literal or a numeric literal and ObjExpr's apparent type has a property with the name
-            //    given by that literal(converted to its string representation in the case of a numeric literal), the property access is of the type of that property.
-            // - Otherwise, if ObjExpr's apparent type has a numeric index signature and IndexExpr is of type Any, the Number primitive type, or an enum type,
-            //    the property access is of the type of that index signature.
-            // - Otherwise, if ObjExpr's apparent type has a string index signature and IndexExpr is of type Any, the String or Number primitive type, or an enum type,
-            //    the property access is of the type of that index signature.
-            // - Otherwise, if IndexExpr is of type Any, the String or Number primitive type, or an enum type, the property access is of type Any.
-
-            // See if we can index as a property.
-            if (node.argumentExpression) {
-                const name = getPropertyNameForIndexedAccess(node.argumentExpression, indexType);
-                if (name !== undefined) {
-                    const prop = getPropertyOfType(objectType, name);
-                    if (prop) {
-                        getNodeLinks(node).resolvedSymbol = prop;
-                        return getTypeOfSymbol(prop);
-                    }
-                    else if (isConstEnum) {
-                        error(node.argumentExpression, Diagnostics.Property_0_does_not_exist_on_const_enum_1, name, symbolToString(objectType.symbol));
-                        return unknownType;
-                    }
-                }
-            }
-
-            // Check for compatible indexer types.
-            const allowedNullableFlags = strictNullChecks ? 0 : TypeFlags.Nullable;
-            if (isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.ESSymbol | allowedNullableFlags)) {
-
-                // Try to use a number indexer.
-                if (isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.NumberLike | allowedNullableFlags) || isForInVariableForNumericPropertyNames(node.argumentExpression)) {
-                    const numberIndexInfo = getIndexInfoOfType(objectType, IndexKind.Number);
-                    if (numberIndexInfo) {
-                        getNodeLinks(node).resolvedIndexInfo = numberIndexInfo;
-                        return numberIndexInfo.type;
+            const propName = getPropertyNameForIndexedAccess(indexExpression, indexType);
+            if (propName !== undefined) {
+                const prop = getPropertyOfType(getApparentType(objectType), propName);
+                if (prop) {
+                    getNodeLinks(node).resolvedSymbol = prop;
+                    if (isAssignmentTarget(node)) {
+                        if (isReferenceToReadonlyEntity(<Expression>node, prop) || isReferenceThroughNamespaceImport(<Expression>node)) {
+                            error(indexExpression, Diagnostics.Cannot_assign_to_0_because_it_is_a_constant_or_a_read_only_property, propName);
+                            return unknownType;
+                        }
                     }
+                    return getTypeOfSymbol(prop);
                 }
-
-                // Try to use string indexing.
-                const stringIndexInfo = getIndexInfoOfType(objectType, IndexKind.String);
-                if (stringIndexInfo) {
-                    getNodeLinks(node).resolvedIndexInfo = stringIndexInfo;
-                    return stringIndexInfo.type;
-                }
-
-                // Fall back to any.
-                if (compilerOptions.noImplicitAny && !compilerOptions.suppressImplicitAnyIndexErrors && !isTypeAny(objectType)) {
-                    error(node, getIndexTypeOfType(objectType, IndexKind.Number) ?
-                        Diagnostics.Element_implicitly_has_an_any_type_because_index_expression_is_not_of_type_number :
-                        Diagnostics.Index_signature_of_object_type_implicitly_has_an_any_type);
-                }
-
-                return anyType;
             }
 
-            // REVIEW: Users should know the type that was actually used.
-            error(node, Diagnostics.An_index_expression_argument_must_be_of_type_string_number_symbol_or_any);
-
-            return unknownType;
+            return getIndexedAccessType(objectType, indexType, node);
         }
 
         /**
@@ -11649,21 +11616,20 @@ namespace ts {
          *    to this symbol, as long as it is a proper symbol reference.
          * Otherwise, returns undefined.
          */
-        function getPropertyNameForIndexedAccess(indexArgumentExpression: Expression, indexArgumentType: Type): string {
-            if (indexArgumentExpression.kind === SyntaxKind.StringLiteral || indexArgumentExpression.kind === SyntaxKind.NumericLiteral) {
-                return (<LiteralExpression>indexArgumentExpression).text;
+        function getPropertyNameForIndexedAccess(indexExpression: Expression, indexType: Type): string {
+            if (indexExpression.kind === SyntaxKind.StringLiteral || indexExpression.kind === SyntaxKind.NumericLiteral) {
+                return (<LiteralExpression>indexExpression).text;
             }
-            if (indexArgumentExpression.kind === SyntaxKind.ElementAccessExpression || indexArgumentExpression.kind === SyntaxKind.PropertyAccessExpression) {
-                const value = getConstantValue(<ElementAccessExpression | PropertyAccessExpression>indexArgumentExpression);
+            if (indexExpression.kind === SyntaxKind.ElementAccessExpression || indexExpression.kind === SyntaxKind.PropertyAccessExpression) {
+                const value = getConstantValue(<ElementAccessExpression | PropertyAccessExpression>indexExpression);
                 if (value !== undefined) {
                     return value.toString();
                 }
             }
-            if (checkThatExpressionIsProperSymbolReference(indexArgumentExpression, indexArgumentType, /*reportError*/ false)) {
-                const rightHandSideName = (<Identifier>(<PropertyAccessExpression>indexArgumentExpression).name).text;
+            if (checkThatExpressionIsProperSymbolReference(indexExpression, indexType, /*reportError*/ false)) {
+                const rightHandSideName = (<Identifier>(<PropertyAccessExpression>indexExpression).name).text;
                 return getPropertyNameForKnownSymbolName(rightHandSideName);
             }
-
             return undefined;
         }
 
@@ -13517,41 +13483,13 @@ namespace ts {
             return false;
         }
 
-        function checkReferenceExpression(expr: Expression, invalidReferenceMessage: DiagnosticMessage, constantVariableMessage: DiagnosticMessage): boolean {
+        function checkReferenceExpression(expr: Expression, invalidReferenceMessage: DiagnosticMessage): boolean {
             // References are combinations of identifiers, parentheses, and property accesses.
             const node = skipParentheses(expr);
             if (node.kind !== SyntaxKind.Identifier && node.kind !== SyntaxKind.PropertyAccessExpression && node.kind !== SyntaxKind.ElementAccessExpression) {
                 error(expr, invalidReferenceMessage);
                 return false;
             }
-            if (node.kind === SyntaxKind.Identifier || node.kind === SyntaxKind.PropertyAccessExpression) {
-                return true;
-            }
-            // Because we get the symbol from the resolvedSymbol property, it might be of kind
-            // SymbolFlags.ExportValue. In this case it is necessary to get the actual export
-            // symbol, which will have the correct flags set on it.
-            const links = getNodeLinks(node);
-            const symbol = getExportSymbolOfValueSymbolIfExported(links.resolvedSymbol);
-            if (symbol) {
-                if (symbol !== unknownSymbol && symbol !== argumentsSymbol) {
-                    // Only variables (and not functions, classes, namespaces, enum objects, or enum members)
-                    // are considered references when referenced using a simple identifier.
-                    // if (node.kind === SyntaxKind.Identifier && !(symbol.flags & SymbolFlags.Variable)) {
-                    //     error(expr, invalidReferenceMessage);
-                    //     return false;
-                    // }
-                    if (isReferenceToReadonlyEntity(node, symbol) || isReferenceThroughNamespaceImport(node)) {
-                        error(expr, constantVariableMessage);
-                        return false;
-                    }
-                }
-            }
-            else if (node.kind === SyntaxKind.ElementAccessExpression) {
-                if (links.resolvedIndexInfo && links.resolvedIndexInfo.isReadonly) {
-                    error(expr, constantVariableMessage);
-                    return false;
-                }
-            }
             return true;
         }
 
@@ -13613,9 +13551,7 @@ namespace ts {
                         Diagnostics.An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type);
                     if (ok) {
                         // run check only if former checks succeeded to avoid reporting cascading errors
-                        checkReferenceExpression(node.operand,
-                            Diagnostics.The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access,
-                            Diagnostics.The_operand_of_an_increment_or_decrement_operator_cannot_be_a_constant_or_a_read_only_property);
+                        checkReferenceExpression(node.operand, Diagnostics.The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access);
                     }
                     return numberType;
             }
@@ -13631,9 +13567,7 @@ namespace ts {
                 Diagnostics.An_arithmetic_operand_must_be_of_type_any_number_or_an_enum_type);
             if (ok) {
                 // run check only if former checks succeeded to avoid reporting cascading errors
-                checkReferenceExpression(node.operand,
-                    Diagnostics.The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access,
-                    Diagnostics.The_operand_of_an_increment_or_decrement_operator_cannot_be_a_constant_or_a_read_only_property);
+                checkReferenceExpression(node.operand, Diagnostics.The_operand_of_an_increment_or_decrement_operator_must_be_a_variable_or_a_property_access);
             }
             return numberType;
         }
@@ -13859,7 +13793,7 @@ namespace ts {
 
         function checkReferenceAssignment(target: Expression, sourceType: Type, contextualMapper?: TypeMapper): Type {
             const targetType = checkExpression(target, contextualMapper);
-            if (checkReferenceExpression(target, Diagnostics.The_left_hand_side_of_an_assignment_expression_must_be_a_variable_or_a_property_access, Diagnostics.Left_hand_side_of_assignment_expression_cannot_be_a_constant_or_a_read_only_property)) {
+            if (checkReferenceExpression(target, Diagnostics.The_left_hand_side_of_an_assignment_expression_must_be_a_variable_or_a_property_access)) {
                 checkTypeAssignableTo(sourceType, targetType, target, /*headMessage*/ undefined);
             }
             return sourceType;
@@ -14142,11 +14076,7 @@ namespace ts {
                     // requires VarExpr to be classified as a reference
                     // A compound assignment furthermore requires VarExpr to be classified as a reference (section 4.1)
                     // and the type of the non - compound operation to be assignable to the type of VarExpr.
-                    const ok = checkReferenceExpression(left,
-                        Diagnostics.The_left_hand_side_of_an_assignment_expression_must_be_a_variable_or_a_property_access,
-                        Diagnostics.Left_hand_side_of_assignment_expression_cannot_be_a_constant_or_a_read_only_property);
-                    // Use default messages
-                    if (ok) {
+                    if (checkReferenceExpression(left, Diagnostics.The_left_hand_side_of_an_assignment_expression_must_be_a_variable_or_a_property_access)) {
                         // to avoid cascading errors check assignability only if 'isReference' check succeeded and no errors were reported
                         checkTypeAssignableTo(valueType, leftType, left, /*headMessage*/ undefined);
                     }
@@ -16588,8 +16518,7 @@ namespace ts {
                 }
                 else {
                     const leftType = checkExpression(varExpr);
-                    checkReferenceExpression(varExpr, /*invalidReferenceMessage*/ Diagnostics.The_left_hand_side_of_a_for_of_statement_must_be_a_variable_or_a_property_access,
-                        /*constantVariableMessage*/ Diagnostics.The_left_hand_side_of_a_for_of_statement_cannot_be_a_constant_or_a_read_only_property);
+                    checkReferenceExpression(varExpr, Diagnostics.The_left_hand_side_of_a_for_of_statement_must_be_a_variable_or_a_property_access);
 
                     // iteratedType will be undefined if the rightType was missing properties/signatures
                     // required to get its iteratedType (like [Symbol.iterator] or next). This may be
@@ -16639,8 +16568,7 @@ namespace ts {
                 }
                 else {
                     // run check only former check succeeded to avoid cascading errors
-                    checkReferenceExpression(varExpr, Diagnostics.The_left_hand_side_of_a_for_in_statement_must_be_a_variable_or_a_property_access,
-                        Diagnostics.The_left_hand_side_of_a_for_in_statement_cannot_be_a_constant_or_a_read_only_property);
+                    checkReferenceExpression(varExpr, Diagnostics.The_left_hand_side_of_a_for_in_statement_must_be_a_variable_or_a_property_access);
                 }
             }
 
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 00b6caf612b9b..e4fc2b7982de2 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1415,14 +1415,6 @@
         "category": "Error",
         "code": 2448
     },
-    "The operand of an increment or decrement operator cannot be a constant or a read-only property.": {
-        "category": "Error",
-        "code": 2449
-    },
-    "Left-hand side of assignment expression cannot be a constant or a read-only property.": {
-        "category": "Error",
-        "code": 2450
-    },
     "Cannot redeclare block-scoped variable '{0}'.": {
         "category": "Error",
         "code": 2451
@@ -1555,14 +1547,6 @@
         "category": "Error",
         "code": 2484
     },
-    "The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.": {
-        "category": "Error",
-        "code": 2485
-    },
-    "The left-hand side of a 'for...in' statement cannot be a constant or a read-only property.": {
-        "category": "Error",
-        "code": 2486
-    },
     "The left-hand side of a 'for...of' statement must be a variable or a property access.": {
         "category": "Error",
         "code": 2487
@@ -1775,6 +1759,10 @@
         "category": "Error",
         "code": 2541
     },
+    "Index signature in type '{0}' only permits reading.": {
+        "category": "Error",
+        "code": 2542
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600
@@ -2921,7 +2909,7 @@
         "category": "Error",
         "code": 7015
     },
-    "Index signature of object type implicitly has an 'any' type.": {
+    "Element implicitly has an 'any' type because type '{0}' has no index signature.": {
         "category": "Error",
         "code": 7017
     },

From 03f8403e85a54a58a5b5597e0c25fced714bfbd5 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 31 Oct 2016 15:29:02 -0700
Subject: [PATCH 134/224] Accept new baselines

---
 .../constDeclarations-access3.errors.txt      |  6 +-
 .../constDeclarations-access4.errors.txt      |  6 +-
 .../constDeclarations-access5.errors.txt      |  6 +-
 .../constEnumBadPropertyNames.errors.txt      |  4 +-
 .../reference/constIndexedAccess.types        |  8 +--
 .../decrementOperatorWithEnumType.errors.txt  | 16 ++---
 ...externalModuleImmutableBindings.errors.txt | 48 +++++++-------
 .../for-inStatementsArrayErrors.errors.txt    |  4 +-
 .../incrementOperatorWithEnumType.errors.txt  | 12 ++--
 .../reference/indexTypeCheck.errors.txt       |  6 +-
 .../indexWithUndefinedAndNull.errors.txt      | 28 ++++++++
 ...ndefinedAndNullStrictNullChecks.errors.txt | 24 +++----
 .../reference/noImplicitAnyForIn.errors.txt   |  8 +--
 .../noImplicitAnyIndexing.errors.txt          | 16 ++---
 ...mplicitAnyStringIndexerOnObject.errors.txt |  4 +-
 ...eationOfElementAccessExpression.errors.txt | 12 ++--
 ...ctTypeWithStringNamedNumericProperty.types | 64 +++++++++----------
 .../reference/parserForStatement2.errors.txt  |  8 ++-
 .../reference/propertyAccess.errors.txt       | 23 ++++---
 .../reference/readonlyMembers.errors.txt      |  8 +--
 .../superSymbolIndexedAccess3.errors.txt      |  6 +-
 .../reference/symbolProperty53.errors.txt     |  6 +-
 22 files changed, 180 insertions(+), 143 deletions(-)
 create mode 100644 tests/baselines/reference/indexWithUndefinedAndNull.errors.txt

diff --git a/tests/baselines/reference/constDeclarations-access3.errors.txt b/tests/baselines/reference/constDeclarations-access3.errors.txt
index 43864d5274dfa..03ea2d29bba92 100644
--- a/tests/baselines/reference/constDeclarations-access3.errors.txt
+++ b/tests/baselines/reference/constDeclarations-access3.errors.txt
@@ -15,7 +15,7 @@ tests/cases/compiler/constDeclarations-access3.ts(22,3): error TS2540: Cannot as
 tests/cases/compiler/constDeclarations-access3.ts(23,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/constDeclarations-access3.ts(24,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/constDeclarations-access3.ts(26,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(28,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(28,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/constDeclarations-access3.ts (18 errors) ====
@@ -81,8 +81,8 @@ tests/cases/compiler/constDeclarations-access3.ts(28,1): error TS2450: Left-hand
 !!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     M["x"] = 0;
-    ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     // OK
     var a = M.x + 1;
diff --git a/tests/baselines/reference/constDeclarations-access4.errors.txt b/tests/baselines/reference/constDeclarations-access4.errors.txt
index d9b63941c764d..a4111c2d7023c 100644
--- a/tests/baselines/reference/constDeclarations-access4.errors.txt
+++ b/tests/baselines/reference/constDeclarations-access4.errors.txt
@@ -15,7 +15,7 @@ tests/cases/compiler/constDeclarations-access4.ts(22,3): error TS2540: Cannot as
 tests/cases/compiler/constDeclarations-access4.ts(23,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/constDeclarations-access4.ts(24,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/constDeclarations-access4.ts(26,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(28,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(28,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/constDeclarations-access4.ts (18 errors) ====
@@ -81,8 +81,8 @@ tests/cases/compiler/constDeclarations-access4.ts(28,1): error TS2450: Left-hand
 !!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     M["x"] = 0;
-    ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     // OK
     var a = M.x + 1;
diff --git a/tests/baselines/reference/constDeclarations-access5.errors.txt b/tests/baselines/reference/constDeclarations-access5.errors.txt
index 72f28b992a988..316465e80b85b 100644
--- a/tests/baselines/reference/constDeclarations-access5.errors.txt
+++ b/tests/baselines/reference/constDeclarations-access5.errors.txt
@@ -15,7 +15,7 @@ tests/cases/compiler/constDeclarations_access_2.ts(18,3): error TS2540: Cannot a
 tests/cases/compiler/constDeclarations_access_2.ts(19,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/constDeclarations_access_2.ts(20,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/constDeclarations_access_2.ts(22,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(24,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(24,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/constDeclarations_access_2.ts (18 errors) ====
@@ -77,8 +77,8 @@ tests/cases/compiler/constDeclarations_access_2.ts(24,1): error TS2450: Left-han
 !!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     m["x"] = 0;
-    ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     // OK
     var a = m.x + 1;
diff --git a/tests/baselines/reference/constEnumBadPropertyNames.errors.txt b/tests/baselines/reference/constEnumBadPropertyNames.errors.txt
index f2330617dea18..09610ca24e57a 100644
--- a/tests/baselines/reference/constEnumBadPropertyNames.errors.txt
+++ b/tests/baselines/reference/constEnumBadPropertyNames.errors.txt
@@ -1,8 +1,8 @@
-tests/cases/compiler/constEnumBadPropertyNames.ts(2,11): error TS2479: Property 'B' does not exist on 'const' enum 'E'.
+tests/cases/compiler/constEnumBadPropertyNames.ts(2,11): error TS2339: Property 'B' does not exist on type 'typeof E'.
 
 
 ==== tests/cases/compiler/constEnumBadPropertyNames.ts (1 errors) ====
     const enum E { A }
     var x = E["B"]
               ~~~
-!!! error TS2479: Property 'B' does not exist on 'const' enum 'E'.
\ No newline at end of file
+!!! error TS2339: Property 'B' does not exist on type 'typeof E'.
\ No newline at end of file
diff --git a/tests/baselines/reference/constIndexedAccess.types b/tests/baselines/reference/constIndexedAccess.types
index 0740a6efc67fb..9e08cf08f4983 100644
--- a/tests/baselines/reference/constIndexedAccess.types
+++ b/tests/baselines/reference/constIndexedAccess.types
@@ -76,16 +76,16 @@ enum numbersNotConst {
 }
 
 let s3 = test[numbersNotConst.zero];
->s3 : any
->test[numbersNotConst.zero] : any
+>s3 : string
+>test[numbersNotConst.zero] : string
 >test : indexAccess
 >numbersNotConst.zero : numbersNotConst.zero
 >numbersNotConst : typeof numbersNotConst
 >zero : numbersNotConst.zero
 
 let n3 = test[numbersNotConst.one];
->n3 : any
->test[numbersNotConst.one] : any
+>n3 : number
+>test[numbersNotConst.one] : number
 >test : indexAccess
 >numbersNotConst.one : numbersNotConst.one
 >numbersNotConst : typeof numbersNotConst
diff --git a/tests/baselines/reference/decrementOperatorWithEnumType.errors.txt b/tests/baselines/reference/decrementOperatorWithEnumType.errors.txt
index bad8dacd85611..aae28d5e417b2 100644
--- a/tests/baselines/reference/decrementOperatorWithEnumType.errors.txt
+++ b/tests/baselines/reference/decrementOperatorWithEnumType.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(6,25): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(6,31): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(7,29): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(10,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(12,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(10,9): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(12,1): error TS2542: Index signature in type 'typeof ENUM1' only permits reading.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(12,7): error TS2304: Cannot find name 'A'.
 
 
@@ -12,19 +12,19 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     
     // expression
     var ResultIsNumber1 = --ENUM1["A"];
-                            ~~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+                                  ~~~
+!!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     var ResultIsNumber2 = ENUM1.A--;
                                 ~
 !!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     
     // miss assignment operator
     --ENUM1["A"];
-      ~~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+            ~~~
+!!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     
     ENUM1[A]--;
     ~~~~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2542: Index signature in type 'typeof ENUM1' only permits reading.
           ~
 !!! error TS2304: Cannot find name 'A'.
\ No newline at end of file
diff --git a/tests/baselines/reference/externalModuleImmutableBindings.errors.txt b/tests/baselines/reference/externalModuleImmutableBindings.errors.txt
index 7454868e361dc..815b5847458e1 100644
--- a/tests/baselines/reference/externalModuleImmutableBindings.errors.txt
+++ b/tests/baselines/reference/externalModuleImmutableBindings.errors.txt
@@ -1,23 +1,23 @@
 tests/cases/compiler/f2.ts(7,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
-tests/cases/compiler/f2.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(8,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(9,7): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
 tests/cases/compiler/f2.ts(12,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
-tests/cases/compiler/f2.ts(13,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(13,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(17,8): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
-tests/cases/compiler/f2.ts(18,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(18,8): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(19,8): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
 tests/cases/compiler/f2.ts(22,8): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
-tests/cases/compiler/f2.ts(23,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(23,8): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(27,12): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(28,12): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
-tests/cases/compiler/f2.ts(29,6): error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
-tests/cases/compiler/f2.ts(30,6): error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(29,12): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(30,12): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(31,12): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
 tests/cases/compiler/f2.ts(32,12): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
 tests/cases/compiler/f2.ts(36,13): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(37,13): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
-tests/cases/compiler/f2.ts(38,6): error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
-tests/cases/compiler/f2.ts(39,6): error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(38,13): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(39,13): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(40,13): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
 tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
 
@@ -36,8 +36,8 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
           ~
 !!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     stuff['x'] = 1;
-    ~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+          ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     stuff.blah = 2;
           ~~~~
 !!! error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
@@ -47,8 +47,8 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
           ~
 !!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     stuff['x']++;
-    ~~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+          ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     stuff['blah']++;
     stuff[n]++;
     
@@ -56,8 +56,8 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
            ~
 !!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     (stuff['x']) = 1;
-    ~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+           ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     (stuff.blah) = 2;
            ~~~~
 !!! error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
@@ -67,8 +67,8 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
            ~
 !!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     (stuff['x'])++;
-    ~~~~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+           ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     (stuff['blah'])++;
     (stuff[n])++;
     
@@ -79,11 +79,11 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
                ~
 !!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for (stuff['x'] in []) {}
-         ~~~~~~~~~~
-!!! error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
+               ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for (stuff['x'] of []) {}
-         ~~~~~~~~~~
-!!! error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+               ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for (stuff.blah in []) {}
                ~~~~
 !!! error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
@@ -100,11 +100,11 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
                 ~
 !!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for ((stuff['x']) in []) {}
-         ~~~~~~~~~~~~
-!!! error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
+                ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for ((stuff['x']) of []) {}
-         ~~~~~~~~~~~~
-!!! error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+                ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for ((stuff.blah) in []) {}
                 ~~~~
 !!! error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
diff --git a/tests/baselines/reference/for-inStatementsArrayErrors.errors.txt b/tests/baselines/reference/for-inStatementsArrayErrors.errors.txt
index 6886d992bb2e5..03361cfcfab09 100644
--- a/tests/baselines/reference/for-inStatementsArrayErrors.errors.txt
+++ b/tests/baselines/reference/for-inStatementsArrayErrors.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(5,14): error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
+tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(5,16): error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(6,16): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(7,9): error TS2365: Operator '===' cannot be applied to types 'string' and 'number'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(9,16): error TS2339: Property 'unknownProperty' does not exist on type 'string'.
@@ -12,7 +12,7 @@ tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.
     
     for (let x in a) {
         let a1 = a[x + 1];
-                 ~~~~~~~~
+                   ~~~~~
 !!! error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
         let a2 = a[x - 1];
                    ~
diff --git a/tests/baselines/reference/incrementOperatorWithEnumType.errors.txt b/tests/baselines/reference/incrementOperatorWithEnumType.errors.txt
index 5dc16bdc511fa..8fdbc34356216 100644
--- a/tests/baselines/reference/incrementOperatorWithEnumType.errors.txt
+++ b/tests/baselines/reference/incrementOperatorWithEnumType.errors.txt
@@ -1,6 +1,6 @@
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(6,25): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(6,31): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(7,29): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(10,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(10,9): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(12,7): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
 
 
@@ -11,16 +11,16 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     
     // expression
     var ResultIsNumber1 = ++ENUM1["B"];
-                            ~~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+                                  ~~~
+!!! error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
     var ResultIsNumber2 = ENUM1.B++;
                                 ~
 !!! error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
     
     // miss assignment operator
     ++ENUM1["B"];
-      ~~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+            ~~~
+!!! error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
     
     ENUM1.B++;
           ~
diff --git a/tests/baselines/reference/indexTypeCheck.errors.txt b/tests/baselines/reference/indexTypeCheck.errors.txt
index 06b844f8321d1..9d839e9eb3022 100644
--- a/tests/baselines/reference/indexTypeCheck.errors.txt
+++ b/tests/baselines/reference/indexTypeCheck.errors.txt
@@ -5,7 +5,7 @@ tests/cases/compiler/indexTypeCheck.ts(22,2): error TS2413: Numeric index type '
 tests/cases/compiler/indexTypeCheck.ts(27,2): error TS2413: Numeric index type 'number' is not assignable to string index type 'string'.
 tests/cases/compiler/indexTypeCheck.ts(32,3): error TS1096: An index signature must have exactly one parameter.
 tests/cases/compiler/indexTypeCheck.ts(36,3): error TS1023: An index signature parameter type must be 'string' or 'number'.
-tests/cases/compiler/indexTypeCheck.ts(51,1): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/compiler/indexTypeCheck.ts(51,8): error TS2538: Type 'Blue' cannot be used as an index type.
 
 
 ==== tests/cases/compiler/indexTypeCheck.ts (8 errors) ====
@@ -74,8 +74,8 @@ tests/cases/compiler/indexTypeCheck.ts(51,1): error TS2342: An index expression
     s[<any>{}]; // ok
     
     yellow[blue]; // error
-    ~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+           ~~~~
+!!! error TS2538: Type 'Blue' cannot be used as an index type.
     
     var x:number[];
     x[0];
diff --git a/tests/baselines/reference/indexWithUndefinedAndNull.errors.txt b/tests/baselines/reference/indexWithUndefinedAndNull.errors.txt
new file mode 100644
index 0000000000000..6d6fa9c39e82c
--- /dev/null
+++ b/tests/baselines/reference/indexWithUndefinedAndNull.errors.txt
@@ -0,0 +1,28 @@
+tests/cases/compiler/indexWithUndefinedAndNull.ts(9,21): error TS2538: Type 'undefined' cannot be used as an index type.
+tests/cases/compiler/indexWithUndefinedAndNull.ts(10,9): error TS2538: Type 'null' cannot be used as an index type.
+tests/cases/compiler/indexWithUndefinedAndNull.ts(11,21): error TS2538: Type 'undefined' cannot be used as an index type.
+tests/cases/compiler/indexWithUndefinedAndNull.ts(12,9): error TS2538: Type 'null' cannot be used as an index type.
+
+
+==== tests/cases/compiler/indexWithUndefinedAndNull.ts (4 errors) ====
+    interface N {
+        [n: number]: string;
+    }
+    interface S {
+        [s: string]: number;
+    }
+    let n: N;
+    let s: S;
+    let str: string = n[undefined];
+                        ~~~~~~~~~
+!!! error TS2538: Type 'undefined' cannot be used as an index type.
+    str = n[null];
+            ~~~~
+!!! error TS2538: Type 'null' cannot be used as an index type.
+    let num: number = s[undefined];
+                        ~~~~~~~~~
+!!! error TS2538: Type 'undefined' cannot be used as an index type.
+    num = s[null];
+            ~~~~
+!!! error TS2538: Type 'null' cannot be used as an index type.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/indexWithUndefinedAndNullStrictNullChecks.errors.txt b/tests/baselines/reference/indexWithUndefinedAndNullStrictNullChecks.errors.txt
index a1fce75c54e9c..764ce212971a7 100644
--- a/tests/baselines/reference/indexWithUndefinedAndNullStrictNullChecks.errors.txt
+++ b/tests/baselines/reference/indexWithUndefinedAndNullStrictNullChecks.errors.txt
@@ -1,11 +1,11 @@
 tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(9,19): error TS2454: Variable 'n' is used before being assigned.
-tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(9,19): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(9,21): error TS2538: Type 'undefined' cannot be used as an index type.
 tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(10,7): error TS2454: Variable 'n' is used before being assigned.
-tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(10,7): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(10,9): error TS2538: Type 'null' cannot be used as an index type.
 tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(11,19): error TS2454: Variable 's' is used before being assigned.
-tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(11,19): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(11,21): error TS2538: Type 'undefined' cannot be used as an index type.
 tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(12,7): error TS2454: Variable 's' is used before being assigned.
-tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(12,7): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(12,9): error TS2538: Type 'null' cannot be used as an index type.
 
 
 ==== tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts (8 errors) ====
@@ -20,21 +20,21 @@ tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(12,7): error T
     let str: string = n[undefined];
                       ~
 !!! error TS2454: Variable 'n' is used before being assigned.
-                      ~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+                        ~~~~~~~~~
+!!! error TS2538: Type 'undefined' cannot be used as an index type.
     str = n[null];
           ~
 !!! error TS2454: Variable 'n' is used before being assigned.
-          ~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+            ~~~~
+!!! error TS2538: Type 'null' cannot be used as an index type.
     let num: number = s[undefined];
                       ~
 !!! error TS2454: Variable 's' is used before being assigned.
-                      ~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+                        ~~~~~~~~~
+!!! error TS2538: Type 'undefined' cannot be used as an index type.
     num = s[null];
           ~
 !!! error TS2454: Variable 's' is used before being assigned.
-          ~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+            ~~~~
+!!! error TS2538: Type 'null' cannot be used as an index type.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/noImplicitAnyForIn.errors.txt b/tests/baselines/reference/noImplicitAnyForIn.errors.txt
index 69b5cd34906fd..3db1c260d517c 100644
--- a/tests/baselines/reference/noImplicitAnyForIn.errors.txt
+++ b/tests/baselines/reference/noImplicitAnyForIn.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/compiler/noImplicitAnyForIn.ts(8,18): error TS7017: Index signature of object type implicitly has an 'any' type.
-tests/cases/compiler/noImplicitAnyForIn.ts(15,18): error TS7017: Index signature of object type implicitly has an 'any' type.
+tests/cases/compiler/noImplicitAnyForIn.ts(8,18): error TS7017: Element implicitly has an 'any' type because type '{}' has no index signature.
+tests/cases/compiler/noImplicitAnyForIn.ts(15,18): error TS7017: Element implicitly has an 'any' type because type '{}' has no index signature.
 tests/cases/compiler/noImplicitAnyForIn.ts(29,5): error TS7005: Variable 'n' implicitly has an 'any[][]' type.
 tests/cases/compiler/noImplicitAnyForIn.ts(31,6): error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
 
@@ -14,7 +14,7 @@ tests/cases/compiler/noImplicitAnyForIn.ts(31,6): error TS2405: The left-hand si
             //Should yield an implicit 'any' error
             var _j = x[i][j];
                      ~~~~~~~
-!!! error TS7017: Index signature of object type implicitly has an 'any' type.
+!!! error TS7017: Element implicitly has an 'any' type because type '{}' has no index signature.
         }
     
         for (var k in x[0]) {
@@ -23,7 +23,7 @@ tests/cases/compiler/noImplicitAnyForIn.ts(31,6): error TS2405: The left-hand si
             //Should yield an implicit 'any' error
             var k2 = k1[k];
                      ~~~~~
-!!! error TS7017: Index signature of object type implicitly has an 'any' type.
+!!! error TS7017: Element implicitly has an 'any' type because type '{}' has no index signature.
         }
     }
     
diff --git a/tests/baselines/reference/noImplicitAnyIndexing.errors.txt b/tests/baselines/reference/noImplicitAnyIndexing.errors.txt
index 8f4cf616bda5f..3274bec5aae49 100644
--- a/tests/baselines/reference/noImplicitAnyIndexing.errors.txt
+++ b/tests/baselines/reference/noImplicitAnyIndexing.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/compiler/noImplicitAnyIndexing.ts(13,26): error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
-tests/cases/compiler/noImplicitAnyIndexing.ts(20,9): error TS7017: Index signature of object type implicitly has an 'any' type.
-tests/cases/compiler/noImplicitAnyIndexing.ts(23,9): error TS7017: Index signature of object type implicitly has an 'any' type.
-tests/cases/compiler/noImplicitAnyIndexing.ts(31,10): error TS7017: Index signature of object type implicitly has an 'any' type.
+tests/cases/compiler/noImplicitAnyIndexing.ts(13,37): error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
+tests/cases/compiler/noImplicitAnyIndexing.ts(20,9): error TS7017: Element implicitly has an 'any' type because type '{}' has no index signature.
+tests/cases/compiler/noImplicitAnyIndexing.ts(23,9): error TS7017: Element implicitly has an 'any' type because type '{}' has no index signature.
+tests/cases/compiler/noImplicitAnyIndexing.ts(31,10): error TS7017: Element implicitly has an 'any' type because type '{}' has no index signature.
 
 
 ==== tests/cases/compiler/noImplicitAnyIndexing.ts (4 errors) ====
@@ -18,7 +18,7 @@ tests/cases/compiler/noImplicitAnyIndexing.ts(31,10): error TS7017: Index signat
     
     // Should be implicit 'any' ; property access fails, no string indexer.
     var strRepresentation3 = MyEmusEnum["monehh"];
-                             ~~~~~~~~~~~~~~~~~~~~
+                                        ~~~~~~~~
 !!! error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
     
     // Should be okay; should be a MyEmusEnum
@@ -28,12 +28,12 @@ tests/cases/compiler/noImplicitAnyIndexing.ts(31,10): error TS7017: Index signat
     // Should report an implicit 'any'.
     var x = {}["hi"];
             ~~~~~~~~
-!!! error TS7017: Index signature of object type implicitly has an 'any' type.
+!!! error TS7017: Element implicitly has an 'any' type because type '{}' has no index signature.
     
     // Should report an implicit 'any'.
     var y = {}[10];
             ~~~~~~
-!!! error TS7017: Index signature of object type implicitly has an 'any' type.
+!!! error TS7017: Element implicitly has an 'any' type because type '{}' has no index signature.
     
     
     var hi: any = "hi";
@@ -43,7 +43,7 @@ tests/cases/compiler/noImplicitAnyIndexing.ts(31,10): error TS7017: Index signat
     // Should report an implicit 'any'.
     var z1 = emptyObj[hi];
              ~~~~~~~~~~~~
-!!! error TS7017: Index signature of object type implicitly has an 'any' type.
+!!! error TS7017: Element implicitly has an 'any' type because type '{}' has no index signature.
     var z2 = (<any>emptyObj)[hi];
     
     interface MyMap<T> {
diff --git a/tests/baselines/reference/noImplicitAnyStringIndexerOnObject.errors.txt b/tests/baselines/reference/noImplicitAnyStringIndexerOnObject.errors.txt
index 5c0878f8ab940..c66a0a831082c 100644
--- a/tests/baselines/reference/noImplicitAnyStringIndexerOnObject.errors.txt
+++ b/tests/baselines/reference/noImplicitAnyStringIndexerOnObject.errors.txt
@@ -1,8 +1,8 @@
-tests/cases/compiler/noImplicitAnyStringIndexerOnObject.ts(2,9): error TS7017: Index signature of object type implicitly has an 'any' type.
+tests/cases/compiler/noImplicitAnyStringIndexerOnObject.ts(2,9): error TS7017: Element implicitly has an 'any' type because type '{}' has no index signature.
 
 
 ==== tests/cases/compiler/noImplicitAnyStringIndexerOnObject.ts (1 errors) ====
     
     var x = {}["hello"];
             ~~~~~~~~~~~
-!!! error TS7017: Index signature of object type implicitly has an 'any' type.
\ No newline at end of file
+!!! error TS7017: Element implicitly has an 'any' type because type '{}' has no index signature.
\ No newline at end of file
diff --git a/tests/baselines/reference/objectCreationOfElementAccessExpression.errors.txt b/tests/baselines/reference/objectCreationOfElementAccessExpression.errors.txt
index ef50db9e4e5eb..fecbee27b58b3 100644
--- a/tests/baselines/reference/objectCreationOfElementAccessExpression.errors.txt
+++ b/tests/baselines/reference/objectCreationOfElementAccessExpression.errors.txt
@@ -1,6 +1,6 @@
-tests/cases/compiler/objectCreationOfElementAccessExpression.ts(53,17): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/compiler/objectCreationOfElementAccessExpression.ts(53,25): error TS2538: Type 'Cookie' cannot be used as an index type.
 tests/cases/compiler/objectCreationOfElementAccessExpression.ts(53,63): error TS2348: Value of type 'typeof Cookie' is not callable. Did you mean to include 'new'?
-tests/cases/compiler/objectCreationOfElementAccessExpression.ts(54,33): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/compiler/objectCreationOfElementAccessExpression.ts(54,41): error TS2538: Type 'Cookie' cannot be used as an index type.
 tests/cases/compiler/objectCreationOfElementAccessExpression.ts(54,79): error TS2348: Value of type 'typeof Cookie' is not callable. Did you mean to include 'new'?
 
 
@@ -58,13 +58,13 @@ tests/cases/compiler/objectCreationOfElementAccessExpression.ts(54,79): error TS
     
     // ElementAccessExpressions can only contain one expression.  There should be a parse error here.
     var foods = new PetFood[new IceCream('Mint chocolate chip') , Cookie('Chocolate chip', false) , new Cookie('Peanut butter', true)];
-                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2538: Type 'Cookie' cannot be used as an index type.
                                                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2348: Value of type 'typeof Cookie' is not callable. Did you mean to include 'new'?
     var foods2: MonsterFood[] = new PetFood[new IceCream('Mint chocolate chip') , Cookie('Chocolate chip', false) , new Cookie('Peanut butter', true)];
-                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+                                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2538: Type 'Cookie' cannot be used as an index type.
                                                                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2348: Value of type 'typeof Cookie' is not callable. Did you mean to include 'new'?
     
\ No newline at end of file
diff --git a/tests/baselines/reference/objectTypeWithStringNamedNumericProperty.types b/tests/baselines/reference/objectTypeWithStringNamedNumericProperty.types
index 5e664fadd2092..e050d33024c54 100644
--- a/tests/baselines/reference/objectTypeWithStringNamedNumericProperty.types
+++ b/tests/baselines/reference/objectTypeWithStringNamedNumericProperty.types
@@ -84,15 +84,15 @@ var r3 = c[1.0]; // same as indexing by 1 when done numerically
 
 // BUG 823822
 var r7 = i[-1];
->r7 : any
->i[-1] : any
+>r7 : Date
+>i[-1] : Date
 >i : I
 >-1 : -1
 >1 : 1
 
 var r7 = i[-1.0];
->r7 : any
->i[-1.0] : any
+>r7 : Date
+>i[-1.0] : Date
 >i : I
 >-1.0 : -1
 >1.0 : 1
@@ -116,8 +116,8 @@ var r10 = i[0x1]
 >0x1 : 1
 
 var r11 = i[-0x1]
->r11 : any
->i[-0x1] : any
+>r11 : Date
+>i[-0x1] : Date
 >i : I
 >-0x1 : -1
 >0x1 : 1
@@ -129,8 +129,8 @@ var r12 = i[01]
 >01 : 1
 
 var r13 = i[-01]
->r13 : any
->i[-01] : any
+>r13 : Date
+>i[-01] : Date
 >i : I
 >-01 : -1
 >01 : 1
@@ -215,15 +215,15 @@ var r3 = c[1.0]; // same as indexing by 1 when done numerically
 
 // BUG 823822
 var r7 = i[-1]; 
->r7 : any
->i[-1] : any
+>r7 : Date
+>i[-1] : Date
 >i : I
 >-1 : -1
 >1 : 1
 
 var r7 = i[-1.0]; 
->r7 : any
->i[-1.0] : any
+>r7 : Date
+>i[-1.0] : Date
 >i : I
 >-1.0 : -1
 >1.0 : 1
@@ -247,8 +247,8 @@ var r10 = i[0x1]
 >0x1 : 1
 
 var r11 = i[-0x1]
->r11 : any
->i[-0x1] : any
+>r11 : Date
+>i[-0x1] : Date
 >i : I
 >-0x1 : -1
 >0x1 : 1
@@ -260,8 +260,8 @@ var r12 = i[01]
 >01 : 1
 
 var r13 = i[-01]
->r13 : any
->i[-01] : any
+>r13 : Date
+>i[-01] : Date
 >i : I
 >-01 : -1
 >01 : 1
@@ -342,15 +342,15 @@ var r3 = c[1.0]; // same as indexing by 1 when done numerically
 
 // BUG 823822
 var r7 = i[-1];
->r7 : any
->i[-1] : any
+>r7 : Date
+>i[-1] : Date
 >i : I
 >-1 : -1
 >1 : 1
 
 var r7 = i[-1.0];
->r7 : any
->i[-1.0] : any
+>r7 : Date
+>i[-1.0] : Date
 >i : I
 >-1.0 : -1
 >1.0 : 1
@@ -374,8 +374,8 @@ var r10 = i[0x1]
 >0x1 : 1
 
 var r11 = i[-0x1]
->r11 : any
->i[-0x1] : any
+>r11 : Date
+>i[-0x1] : Date
 >i : I
 >-0x1 : -1
 >0x1 : 1
@@ -387,8 +387,8 @@ var r12 = i[01]
 >01 : 1
 
 var r13 = i[-01]
->r13 : any
->i[-01] : any
+>r13 : Date
+>i[-01] : Date
 >i : I
 >-01 : -1
 >01 : 1
@@ -482,15 +482,15 @@ var r3 = c[1.0]; // same as indexing by 1 when done numerically
 
 // BUG 823822
 var r7 = i[-1];
->r7 : any
->i[-1] : any
+>r7 : Date
+>i[-1] : Date
 >i : I
 >-1 : -1
 >1 : 1
 
 var r7 = i[-1.0];
->r7 : any
->i[-1.0] : any
+>r7 : Date
+>i[-1.0] : Date
 >i : I
 >-1.0 : -1
 >1.0 : 1
@@ -514,8 +514,8 @@ var r10 = i[0x1]
 >0x1 : 1
 
 var r11 = i[-0x1]
->r11 : any
->i[-0x1] : any
+>r11 : Date
+>i[-0x1] : Date
 >i : I
 >-0x1 : -1
 >0x1 : 1
@@ -527,8 +527,8 @@ var r12 = i[01]
 >01 : 1
 
 var r13 = i[-01]
->r13 : any
->i[-01] : any
+>r13 : Date
+>i[-01] : Date
 >i : I
 >-01 : -1
 >01 : 1
diff --git a/tests/baselines/reference/parserForStatement2.errors.txt b/tests/baselines/reference/parserForStatement2.errors.txt
index 59d6dd6dec8f4..68ab999b657a5 100644
--- a/tests/baselines/reference/parserForStatement2.errors.txt
+++ b/tests/baselines/reference/parserForStatement2.errors.txt
@@ -1,11 +1,17 @@
+tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement2.ts(4,13): error TS2538: Type 'undefined' cannot be used as an index type.
+tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement2.ts(4,20): error TS2538: Type 'undefined' cannot be used as an index type.
 tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement2.ts(4,30): error TS2304: Cannot find name 'd'.
 
 
-==== tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement2.ts (1 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/Statements/parserForStatement2.ts (3 errors) ====
     var a;
     var b = [];
     var c;
     for (a in b[c] = b[c] || [], d) {
+                ~
+!!! error TS2538: Type 'undefined' cannot be used as an index type.
+                       ~
+!!! error TS2538: Type 'undefined' cannot be used as an index type.
                                  ~
 !!! error TS2304: Cannot find name 'd'.
     
diff --git a/tests/baselines/reference/propertyAccess.errors.txt b/tests/baselines/reference/propertyAccess.errors.txt
index b32449561743c..a183ad79c1129 100644
--- a/tests/baselines/reference/propertyAccess.errors.txt
+++ b/tests/baselines/reference/propertyAccess.errors.txt
@@ -1,12 +1,13 @@
 tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(11,55): error TS2322: Type '{ 3: string; 'three': string; }' is not assignable to type '{ [n: number]: string; }'.
   Object literal may only specify known properties, and ''three'' does not exist in type '{ [n: number]: string; }'.
 tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(45,14): error TS2339: Property 'qqq' does not exist on type '{ 10: string; x: string; y: number; z: { n: string; m: number; o: () => boolean; }; 'literal property': number; }'.
-tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(80,10): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
-tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(117,10): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
-tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(140,12): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(80,19): error TS2538: Type '{ name: string; }' cannot be used as an index type.
+tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(117,18): error TS2538: Type '{ name: string; }' cannot be used as an index type.
+tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(140,22): error TS2538: Type '{ name: string; }' cannot be used as an index type.
+tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(149,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'x3' must be of type 'A | B', but here has type 'A'.
 
 
-==== tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts (5 errors) ====
+==== tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts (6 errors) ====
     class A {
         a: number;
     }
@@ -92,8 +93,8 @@ tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(140,12): er
     
     // Bracket notation property access using value of other type on type with numeric index signature and no string index signature
     var ll = numIndex[someObject]; // Error
-             ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+                      ~~~~~~~~~~
+!!! error TS2538: Type '{ name: string; }' cannot be used as an index type.
     
     // Bracket notation property access using string value on type with string index signature and no numeric index signature
     var mm = strIndex['N'];
@@ -131,8 +132,8 @@ tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(140,12): er
     
     // Bracket notation property access using values of other types on type with no index signatures
     var uu = noIndex[someObject]; // Error
-             ~~~~~~~~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+                     ~~~~~~~~~~
+!!! error TS2538: Type '{ name: string; }' cannot be used as an index type.
     
     // Bracket notation property access using numeric value on type with numeric index signature and string index signature
     var vv = noIndex[32];
@@ -156,8 +157,8 @@ tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(140,12): er
     
     // Bracket notation property access using value of other type on type with numeric index signature and no string index signature and string index signature
     var zzzz = bothIndex[someObject]; // Error
-               ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+                         ~~~~~~~~~~
+!!! error TS2538: Type '{ name: string; }' cannot be used as an index type.
     
     var x1 = numIndex[stringOrNumber];
     var x1: any;
@@ -167,4 +168,6 @@ tests/cases/conformance/expressions/propertyAccess/propertyAccess.ts(140,12): er
     
     var x3 = bothIndex[stringOrNumber];
     var x3: A;
+        ~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'x3' must be of type 'A | B', but here has type 'A'.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/readonlyMembers.errors.txt b/tests/baselines/reference/readonlyMembers.errors.txt
index bea3a81bf7c99..7a6b74359d16e 100644
--- a/tests/baselines/reference/readonlyMembers.errors.txt
+++ b/tests/baselines/reference/readonlyMembers.errors.txt
@@ -11,8 +11,8 @@ tests/cases/compiler/readonlyMembers.ts(36,3): error TS2540: Cannot assign to 'a
 tests/cases/compiler/readonlyMembers.ts(40,3): error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
 tests/cases/compiler/readonlyMembers.ts(49,3): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
 tests/cases/compiler/readonlyMembers.ts(56,3): error TS2540: Cannot assign to 'a' because it is a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(62,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/readonlyMembers.ts(65,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/readonlyMembers.ts(62,1): error TS2542: Index signature in type '{ readonly [x: string]: string; }' only permits reading.
+tests/cases/compiler/readonlyMembers.ts(65,1): error TS2542: Index signature in type '{ [x: string]: string; readonly [x: number]: string; }' only permits reading.
 
 
 ==== tests/cases/compiler/readonlyMembers.ts (15 errors) ====
@@ -105,10 +105,10 @@ tests/cases/compiler/readonlyMembers.ts(65,1): error TS2450: Left-hand side of a
     let s = xx["foo"];
     xx["foo"] = "abc";  // Error
     ~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2542: Index signature in type '{ readonly [x: string]: string; }' only permits reading.
     
     let yy: { readonly [x: number]: string, [x: string]: string };
     yy[1] = "abc";  // Error
     ~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2542: Index signature in type '{ [x: string]: string; readonly [x: number]: string; }' only permits reading.
     yy["foo"] = "abc";
\ No newline at end of file
diff --git a/tests/baselines/reference/superSymbolIndexedAccess3.errors.txt b/tests/baselines/reference/superSymbolIndexedAccess3.errors.txt
index 1cac31dec4029..a7011e669104c 100644
--- a/tests/baselines/reference/superSymbolIndexedAccess3.errors.txt
+++ b/tests/baselines/reference/superSymbolIndexedAccess3.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/expressions/superPropertyAccess/superSymbolIndexedAccess3.ts(11,16): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/expressions/superPropertyAccess/superSymbolIndexedAccess3.ts(11,22): error TS2538: Type 'typeof Bar' cannot be used as an index type.
 
 
 ==== tests/cases/conformance/expressions/superPropertyAccess/superSymbolIndexedAccess3.ts (1 errors) ====
@@ -13,7 +13,7 @@ tests/cases/conformance/expressions/superPropertyAccess/superSymbolIndexedAccess
     class Bar extends Foo {
         [symbol]() {
             return super[Bar]();
-                   ~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+                         ~~~
+!!! error TS2538: Type 'typeof Bar' cannot be used as an index type.
         }
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/symbolProperty53.errors.txt b/tests/baselines/reference/symbolProperty53.errors.txt
index 03002cd92b28f..faea841358707 100644
--- a/tests/baselines/reference/symbolProperty53.errors.txt
+++ b/tests/baselines/reference/symbolProperty53.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/es6/Symbols/symbolProperty53.ts(2,5): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
-tests/cases/conformance/es6/Symbols/symbolProperty53.ts(5,1): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/conformance/es6/Symbols/symbolProperty53.ts(5,5): error TS2538: Type '(key: string) => symbol' cannot be used as an index type.
 
 
 ==== tests/cases/conformance/es6/Symbols/symbolProperty53.ts (2 errors) ====
@@ -10,5 +10,5 @@ tests/cases/conformance/es6/Symbols/symbolProperty53.ts(5,1): error TS2342: An i
     };
     
     obj[Symbol.for];
-    ~~~~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
\ No newline at end of file
+        ~~~~~~~~~~
+!!! error TS2538: Type '(key: string) => symbol' cannot be used as an index type.
\ No newline at end of file

From 8d9356f264eaec4f7bfd80d602bcba628ab295ab Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 31 Oct 2016 15:43:50 -0700
Subject: [PATCH 135/224] Accept additional baselines

---
 .../amd/nodeModulesMaxDepthExceeded.errors.txt              | 6 +++---
 .../node/nodeModulesMaxDepthExceeded.errors.txt             | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/tests/baselines/reference/project/nodeModulesMaxDepthExceeded/amd/nodeModulesMaxDepthExceeded.errors.txt b/tests/baselines/reference/project/nodeModulesMaxDepthExceeded/amd/nodeModulesMaxDepthExceeded.errors.txt
index 6d95ac42c8f10..99e7b193f0c42 100644
--- a/tests/baselines/reference/project/nodeModulesMaxDepthExceeded/amd/nodeModulesMaxDepthExceeded.errors.txt
+++ b/tests/baselines/reference/project/nodeModulesMaxDepthExceeded/amd/nodeModulesMaxDepthExceeded.errors.txt
@@ -1,5 +1,5 @@
 maxDepthExceeded/root.ts(3,1): error TS2322: Type '"10"' is not assignable to type 'number'.
-maxDepthExceeded/root.ts(4,1): error TS2322: Type '42' is not assignable to type 'true'.
+maxDepthExceeded/root.ts(4,4): error TS2540: Cannot assign to 'rel' because it is a constant or a read-only property.
 
 
 ==== entry.js (0 errors) ====
@@ -36,8 +36,8 @@ maxDepthExceeded/root.ts(4,1): error TS2322: Type '42' is not assignable to type
     ~~~~~~~
 !!! error TS2322: Type '"10"' is not assignable to type 'number'.
     m1.rel = 42; // Error: Should be boolean
-    ~~~~~~
-!!! error TS2322: Type '42' is not assignable to type 'true'.
+       ~~~
+!!! error TS2540: Cannot assign to 'rel' because it is a constant or a read-only property.
     
     m1.f2.person.age = "10"; // OK if stopped at 2 modules: person will be "any".
     
\ No newline at end of file
diff --git a/tests/baselines/reference/project/nodeModulesMaxDepthExceeded/node/nodeModulesMaxDepthExceeded.errors.txt b/tests/baselines/reference/project/nodeModulesMaxDepthExceeded/node/nodeModulesMaxDepthExceeded.errors.txt
index 6d95ac42c8f10..99e7b193f0c42 100644
--- a/tests/baselines/reference/project/nodeModulesMaxDepthExceeded/node/nodeModulesMaxDepthExceeded.errors.txt
+++ b/tests/baselines/reference/project/nodeModulesMaxDepthExceeded/node/nodeModulesMaxDepthExceeded.errors.txt
@@ -1,5 +1,5 @@
 maxDepthExceeded/root.ts(3,1): error TS2322: Type '"10"' is not assignable to type 'number'.
-maxDepthExceeded/root.ts(4,1): error TS2322: Type '42' is not assignable to type 'true'.
+maxDepthExceeded/root.ts(4,4): error TS2540: Cannot assign to 'rel' because it is a constant or a read-only property.
 
 
 ==== entry.js (0 errors) ====
@@ -36,8 +36,8 @@ maxDepthExceeded/root.ts(4,1): error TS2322: Type '42' is not assignable to type
     ~~~~~~~
 !!! error TS2322: Type '"10"' is not assignable to type 'number'.
     m1.rel = 42; // Error: Should be boolean
-    ~~~~~~
-!!! error TS2322: Type '42' is not assignable to type 'true'.
+       ~~~
+!!! error TS2540: Cannot assign to 'rel' because it is a constant or a read-only property.
     
     m1.f2.person.age = "10"; // OK if stopped at 2 modules: person will be "any".
     
\ No newline at end of file

From de6751b80c6b8bb141d09222dd908ef999073512 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Tue, 1 Nov 2016 08:22:56 -0700
Subject: [PATCH 136/224] Make `cachingInServerLSHost` tests work with
 `runtests-browser`

---
 .../unittests/cachingInServerLSHost.ts        | 36 ++++++-------------
 1 file changed, 10 insertions(+), 26 deletions(-)

diff --git a/src/harness/unittests/cachingInServerLSHost.ts b/src/harness/unittests/cachingInServerLSHost.ts
index 953edd98b6ab4..1100bb3663b59 100644
--- a/src/harness/unittests/cachingInServerLSHost.ts
+++ b/src/harness/unittests/cachingInServerLSHost.ts
@@ -22,33 +22,17 @@ namespace ts {
             newLine: "\r\n",
             useCaseSensitiveFileNames: false,
             write: noop,
-            readFile: (path: string): string => {
-                return path in fileMap ? fileMap[path].content : undefined;
-            },
-            writeFile: (_path: string, _data: string, _writeByteOrderMark?: boolean) => {
-                return ts.notImplemented();
-            },
-            resolvePath: (_path: string): string => {
-                return ts.notImplemented();
-            },
-            fileExists: (path: string): boolean => {
-                return path in fileMap;
-            },
-            directoryExists: (path: string): boolean => {
-                return existingDirectories[path] || false;
-            },
+            readFile: path => path in fileMap ? fileMap[path].content : undefined,
+            writeFile: notImplemented,
+            resolvePath: notImplemented,
+            fileExists: path => path in fileMap,
+            directoryExists: path => existingDirectories[path] || false,
             createDirectory: noop,
-            getExecutingFilePath: (): string => {
-                return "";
-            },
-            getCurrentDirectory: (): string => {
-                return "";
-            },
+            getExecutingFilePath: () => "",
+            getCurrentDirectory: () => "",
             getDirectories: () => [],
             getEnvironmentVariable: () => "",
-            readDirectory: (_path: string, _extension?: string[], _exclude?: string[], _include?: string[]): string[] => {
-                return ts.notImplemented();
-            },
+            readDirectory: notImplemented,
             exit: noop,
             watchFile: () => ({
                 close: noop
@@ -58,8 +42,8 @@ namespace ts {
             }),
             setTimeout,
             clearTimeout,
-            setImmediate,
-            clearImmediate
+            setImmediate: typeof setImmediate !== "undefined" ? setImmediate : action => setTimeout(action, 0),
+            clearImmediate: typeof clearImmediate !== "undefined" ? clearImmediate : clearTimeout
         };
     }
 

From d7f5fc8fcf1c083029588217303324a145c20650 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 1 Nov 2016 09:09:40 -0700
Subject: [PATCH 137/224] Get literal type only once

---
 src/compiler/checker.ts | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 2d05e16ef825e..326d84278be24 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -16882,7 +16882,8 @@ namespace ts {
             let firstDefaultClause: CaseOrDefaultClause;
             let hasDuplicateDefaultClause = false;
 
-            let expressionType = checkExpression(node.expression);
+            const expressionType = checkExpression(node.expression);
+            const expressionIsLiteral = isLiteralType(expressionType);
             forEach(node.caseBlock.clauses, clause => {
                 // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
                 if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -16905,14 +16906,14 @@ namespace ts {
                     // to or from the type of the 'switch' expression.
                     let caseType = checkExpression(caseClause.expression);
                     const caseIsLiteral = isLiteralType(caseType);
-                    const expressionIsLiteral = isLiteralType(expressionType);
+                    let literalExpressionType = expressionType;
                     if (!caseIsLiteral || !expressionIsLiteral) {
                         caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
-                        expressionType = expressionIsLiteral ? getBaseTypeOfLiteralType(expressionType) : expressionType;
+                        literalExpressionType = getBaseTypeOfLiteralType(expressionType);
                     }
-                    if (!isTypeEqualityComparableTo(expressionType, caseType)) {
+                    if (!isTypeEqualityComparableTo(literalExpressionType, caseType)) {
                         // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
-                        checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
+                        checkTypeComparableTo(caseType, literalExpressionType, caseClause.expression, /*headMessage*/ undefined);
                     }
                 }
                 forEach(clause.statements, checkSourceElement);

From 357d58b4f1ea650e8b261a45aef66febaaadc55e Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 1 Nov 2016 09:10:39 -0700
Subject: [PATCH 138/224] Update baselines

---
 ...witchCasesExpressionTypeMismatch.errors.txt | 18 +++++++++++-------
 .../switchCasesExpressionTypeMismatch.js       |  7 ++++---
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt b/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt
index 26d39efef48ec..7a5fd12182e4e 100644
--- a/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt
+++ b/tests/baselines/reference/switchCasesExpressionTypeMismatch.errors.txt
@@ -1,9 +1,10 @@
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(4,10): error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type 'string' is not comparable to type 'number'.
-tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'boolean' is not comparable to type 'number'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(5,10): error TS2678: Type '"sss"' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(6,10): error TS2678: Type '123' is not comparable to type '0'.
+tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: Type 'true' is not comparable to type '0'.
 
 
-==== tests/cases/compiler/switchCasesExpressionTypeMismatch.ts (3 errors) ====
+==== tests/cases/compiler/switchCasesExpressionTypeMismatch.ts (4 errors) ====
     class Foo { }
     
     switch (0) {
@@ -12,11 +13,13 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
 !!! error TS2678: Type 'typeof Foo' is not comparable to type 'number'.
         case "sss": break;  // Error
              ~~~~~
-!!! error TS2678: Type 'string' is not comparable to type 'number'.
-        case 123: break;    // No Error
+!!! error TS2678: Type '"sss"' is not comparable to type '0'.
+        case 123: break;    // Error
+             ~~~
+!!! error TS2678: Type '123' is not comparable to type '0'.
         case true: break;   // Error
              ~~~~
-!!! error TS2678: Type 'boolean' is not comparable to type 'number'.
+!!! error TS2678: Type 'true' is not comparable to type '0'.
     }
     
     var s: any = 0;
@@ -27,4 +30,5 @@ tests/cases/compiler/switchCasesExpressionTypeMismatch.ts(7,10): error TS2678: T
         case "sss": break;
         case 123: break;
         case true: break;
-    }
\ No newline at end of file
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/switchCasesExpressionTypeMismatch.js b/tests/baselines/reference/switchCasesExpressionTypeMismatch.js
index ba929691d2536..43a4322457938 100644
--- a/tests/baselines/reference/switchCasesExpressionTypeMismatch.js
+++ b/tests/baselines/reference/switchCasesExpressionTypeMismatch.js
@@ -4,7 +4,7 @@ class Foo { }
 switch (0) {
     case Foo: break;    // Error
     case "sss": break;  // Error
-    case 123: break;    // No Error
+    case 123: break;    // Error
     case true: break;   // Error
 }
 
@@ -16,7 +16,8 @@ switch (s) {
     case "sss": break;
     case 123: break;
     case true: break;
-}
+}
+
 
 //// [switchCasesExpressionTypeMismatch.js]
 var Foo = (function () {
@@ -27,7 +28,7 @@ var Foo = (function () {
 switch (0) {
     case Foo: break; // Error
     case "sss": break; // Error
-    case 123: break; // No Error
+    case 123: break; // Error
     case true: break; // Error
 }
 var s = 0;

From d58a13f6a1c8020e9ab8d88355300e1eb81b5134 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Tue, 1 Nov 2016 10:07:30 -0700
Subject: [PATCH 139/224] Add missed test update

---
 tests/cases/compiler/switchCasesExpressionTypeMismatch.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/cases/compiler/switchCasesExpressionTypeMismatch.ts b/tests/cases/compiler/switchCasesExpressionTypeMismatch.ts
index 4de01ebba175c..ee547705b84d2 100644
--- a/tests/cases/compiler/switchCasesExpressionTypeMismatch.ts
+++ b/tests/cases/compiler/switchCasesExpressionTypeMismatch.ts
@@ -3,7 +3,7 @@ class Foo { }
 switch (0) {
     case Foo: break;    // Error
     case "sss": break;  // Error
-    case 123: break;    // No Error
+    case 123: break;    // Error
     case true: break;   // Error
 }
 
@@ -15,4 +15,4 @@ switch (s) {
     case "sss": break;
     case 123: break;
     case true: break;
-}
\ No newline at end of file
+}

From 41c20545e1891e9b1359e107e67dff666815581f Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Tue, 1 Nov 2016 10:17:08 -0700
Subject: [PATCH 140/224] Improve unification by moving more logic to
 getIndexedAccessType

---
 src/compiler/checker.ts | 73 +++++++++++------------------------------
 1 file changed, 19 insertions(+), 54 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 2feec887cc179..31aab95ffb1bc 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5738,14 +5738,24 @@ namespace ts {
             return indexedAccessTypes[objectType.id] || (indexedAccessTypes[objectType.id] = createIndexedAccessType(objectType, indexType));
         }
 
-        function getPropertyTypeForIndexType(objectType: Type, indexType: Type, accessNode?: ElementAccessExpression | IndexedAccessTypeNode) {
+        function getPropertyTypeForIndexType(objectType: Type, indexType: Type, accessNode: ElementAccessExpression | IndexedAccessTypeNode, cacheSymbol: boolean) {
             const accessExpression = accessNode && accessNode.kind === SyntaxKind.ElementAccessExpression ? <ElementAccessExpression>accessNode : undefined;
-            if (indexType.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral | TypeFlags.EnumLiteral)) {
-                const prop = getPropertyOfType(objectType, escapeIdentifier((<LiteralType>indexType).text));
+            const propName = indexType.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral | TypeFlags.EnumLiteral) ?
+                (<LiteralType>indexType).text :
+                accessExpression && checkThatExpressionIsProperSymbolReference(accessExpression.argumentExpression, indexType, /*reportError*/ false) ?
+                    getPropertyNameForKnownSymbolName((<Identifier>(<PropertyAccessExpression>accessExpression.argumentExpression).name).text) :
+                    undefined;
+            if (propName) {
+                const prop = getPropertyOfType(objectType, propName);
                 if (prop) {
-                    if (accessExpression && isAssignmentTarget(accessExpression) && isReadonlySymbol(prop)) {
-                        error(accessExpression.argumentExpression, Diagnostics.Cannot_assign_to_0_because_it_is_a_constant_or_a_read_only_property, symbolToString(prop));
-                        return unknownType;
+                    if (accessExpression) {
+                        if (isAssignmentTarget(accessExpression) && (isReferenceToReadonlyEntity(accessExpression, prop) || isReferenceThroughNamespaceImport(accessExpression))) {
+                            error(accessExpression.argumentExpression, Diagnostics.Cannot_assign_to_0_because_it_is_a_constant_or_a_read_only_property, symbolToString(prop));
+                            return unknownType;
+                        }
+                        if (cacheSymbol) {
+                            getNodeLinks(accessNode).resolvedSymbol = prop;
+                        }
                     }
                     return getTypeOfSymbol(prop);
                 }
@@ -5798,10 +5808,11 @@ namespace ts {
                 }
                 return getIndexedAccessTypeForTypeParameter(objectType, <TypeParameter>indexType);
             }
+            const apparentType = getApparentType(objectType);
             if (indexType.flags & TypeFlags.Union && !(indexType.flags & TypeFlags.Primitive)) {
                 const propTypes: Type[] = [];
                 for (const t of (<UnionType>indexType).types) {
-                    const propType = getPropertyTypeForIndexType(objectType, t, accessNode);
+                    const propType = getPropertyTypeForIndexType(apparentType, t, accessNode, /*cacheSymbol*/ false);
                     if (propType === unknownType) {
                         return unknownType;
                     }
@@ -5809,7 +5820,7 @@ namespace ts {
                 }
                 return getUnionType(propTypes);
             }
-            return getPropertyTypeForIndexType(objectType, indexType, accessNode);
+            return getPropertyTypeForIndexType(apparentType, indexType, accessNode, /*cacheSymbol*/ true);
         }
 
         function getTypeFromIndexedAccessTypeNode(node: IndexedAccessTypeNode) {
@@ -11644,55 +11655,9 @@ namespace ts {
                 return unknownType;
             }
 
-            const propName = getPropertyNameForIndexedAccess(indexExpression, indexType);
-            if (propName !== undefined) {
-                const prop = getPropertyOfType(getApparentType(objectType), propName);
-                if (prop) {
-                    getNodeLinks(node).resolvedSymbol = prop;
-                    if (isAssignmentTarget(node)) {
-                        if (isReferenceToReadonlyEntity(<Expression>node, prop) || isReferenceThroughNamespaceImport(<Expression>node)) {
-                            error(indexExpression, Diagnostics.Cannot_assign_to_0_because_it_is_a_constant_or_a_read_only_property, propName);
-                            return unknownType;
-                        }
-                    }
-                    return getTypeOfSymbol(prop);
-                }
-            }
-
             return getIndexedAccessType(objectType, indexType, node);
         }
 
-        /**
-         * If indexArgumentExpression is a string literal or number literal, returns its text.
-         * If indexArgumentExpression is a constant value, returns its string value.
-         * If indexArgumentExpression is a well known symbol, returns the property name corresponding
-         *    to this symbol, as long as it is a proper symbol reference.
-         * Otherwise, returns undefined.
-         */
-        function getPropertyNameForIndexedAccess(indexExpression: Expression, indexType: Type): string {
-            if (indexExpression.kind === SyntaxKind.StringLiteral || indexExpression.kind === SyntaxKind.NumericLiteral) {
-                return (<LiteralExpression>indexExpression).text;
-            }
-            if (indexExpression.kind === SyntaxKind.ElementAccessExpression || indexExpression.kind === SyntaxKind.PropertyAccessExpression) {
-                const value = getConstantValue(<ElementAccessExpression | PropertyAccessExpression>indexExpression);
-                if (value !== undefined) {
-                    return value.toString();
-                }
-            }
-            if (checkThatExpressionIsProperSymbolReference(indexExpression, indexType, /*reportError*/ false)) {
-                const rightHandSideName = (<Identifier>(<PropertyAccessExpression>indexExpression).name).text;
-                return getPropertyNameForKnownSymbolName(rightHandSideName);
-            }
-            return undefined;
-        }
-
-        /**
-         * A proper symbol reference requires the following:
-         *   1. The property access denotes a property that exists
-         *   2. The expression is of the form Symbol.<identifier>
-         *   3. The property access is of the primitive type symbol.
-         *   4. Symbol in this context resolves to the global Symbol object
-         */
         function checkThatExpressionIsProperSymbolReference(expression: Expression, expressionType: Type, reportError: boolean): boolean {
             if (expressionType === unknownType) {
                 // There is already an error, so no need to report one.

From d896d3f8a91d19814c35103244a9e17e01cafe87 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Tue, 1 Nov 2016 11:05:09 -0700
Subject: [PATCH 141/224] Add test cases to report errors for decorators in js
 file

---
 src/compiler/program.ts                            |  6 ++++++
 src/compiler/utilities.ts                          |  4 ++++
 .../baselines/reference/decoratorInJsFile.symbols  | 12 ++++++++++++
 tests/baselines/reference/decoratorInJsFile.types  | 14 ++++++++++++++
 .../reference/decoratorInJsFile1.errors.txt        | 13 +++++++++++++
 tests/cases/compiler/decoratorInJsFile.ts          | 12 ++++++++++++
 tests/cases/compiler/decoratorInJsFile1.ts         | 10 ++++++++++
 7 files changed, 71 insertions(+)
 create mode 100644 tests/baselines/reference/decoratorInJsFile.symbols
 create mode 100644 tests/baselines/reference/decoratorInJsFile.types
 create mode 100644 tests/baselines/reference/decoratorInJsFile1.errors.txt
 create mode 100644 tests/cases/compiler/decoratorInJsFile.ts
 create mode 100644 tests/cases/compiler/decoratorInJsFile1.ts

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 726df380e81b1..1eeeded5d363d 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -943,6 +943,12 @@ namespace ts {
 
                     return false;
                 }
+
+                // Since these are syntactic diagnostics, parent might not have been set
+                // this means the sourceFile cannot be infered from the node
+                function createDiagnosticForNode(node: Node, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number): Diagnostic {
+                    return createDiagnosticForNodeInSourceFile(sourceFile, node, message, arg0, arg1, arg2);
+                }
             });
         }
 
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index d78418e1976db..84c27f6397b8b 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -498,6 +498,10 @@ namespace ts {
 
     export function createDiagnosticForNode(node: Node, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number): Diagnostic {
         const sourceFile = getSourceFileOfNode(node);
+        return createDiagnosticForNodeInSourceFile(sourceFile, node, message, arg0, arg1, arg2);
+    }
+
+    export function createDiagnosticForNodeInSourceFile(sourceFile: SourceFile, node: Node, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number): Diagnostic {
         const span = getErrorSpanForNode(sourceFile, node);
         return createFileDiagnostic(sourceFile, span.start, span.length, message, arg0, arg1, arg2);
     }
diff --git a/tests/baselines/reference/decoratorInJsFile.symbols b/tests/baselines/reference/decoratorInJsFile.symbols
new file mode 100644
index 0000000000000..1ad477095c1be
--- /dev/null
+++ b/tests/baselines/reference/decoratorInJsFile.symbols
@@ -0,0 +1,12 @@
+=== tests/cases/compiler/a.js ===
+
+@SomeDecorator
+class SomeClass {
+>SomeClass : Symbol(SomeClass, Decl(a.js, 0, 0))
+
+    foo(x: number) {
+>foo : Symbol(SomeClass.foo, Decl(a.js, 2, 17))
+>x : Symbol(x, Decl(a.js, 3, 8))
+
+    }
+}
diff --git a/tests/baselines/reference/decoratorInJsFile.types b/tests/baselines/reference/decoratorInJsFile.types
new file mode 100644
index 0000000000000..494039794604b
--- /dev/null
+++ b/tests/baselines/reference/decoratorInJsFile.types
@@ -0,0 +1,14 @@
+=== tests/cases/compiler/a.js ===
+
+@SomeDecorator
+>SomeDecorator : any
+
+class SomeClass {
+>SomeClass : SomeClass
+
+    foo(x: number) {
+>foo : (x: number) => void
+>x : number
+
+    }
+}
diff --git a/tests/baselines/reference/decoratorInJsFile1.errors.txt b/tests/baselines/reference/decoratorInJsFile1.errors.txt
new file mode 100644
index 0000000000000..a90aa922f96a7
--- /dev/null
+++ b/tests/baselines/reference/decoratorInJsFile1.errors.txt
@@ -0,0 +1,13 @@
+tests/cases/compiler/a.js(2,1): error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option to remove this warning.
+
+
+==== tests/cases/compiler/a.js (1 errors) ====
+    
+    @SomeDecorator
+    ~~~~~~~~~~~~~~
+!!! error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option to remove this warning.
+    class SomeClass {
+        foo(x: number) {
+    
+        }
+    }
\ No newline at end of file
diff --git a/tests/cases/compiler/decoratorInJsFile.ts b/tests/cases/compiler/decoratorInJsFile.ts
new file mode 100644
index 0000000000000..611be319209dd
--- /dev/null
+++ b/tests/cases/compiler/decoratorInJsFile.ts
@@ -0,0 +1,12 @@
+// @experimentaldecorators: true
+// @emitdecoratormetadata: true
+// @allowjs: true
+// @noEmit: true
+
+// @filename: a.js
+@SomeDecorator
+class SomeClass {
+    foo(x: number) {
+
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/decoratorInJsFile1.ts b/tests/cases/compiler/decoratorInJsFile1.ts
new file mode 100644
index 0000000000000..6bbe38cb8355d
--- /dev/null
+++ b/tests/cases/compiler/decoratorInJsFile1.ts
@@ -0,0 +1,10 @@
+// @allowjs: true
+// @noEmit: true
+
+// @filename: a.js
+@SomeDecorator
+class SomeClass {
+    foo(x: number) {
+
+    }
+}
\ No newline at end of file

From 06331b57de68c603ad7d9e7cc793b48fd58a3440 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Tue, 1 Nov 2016 12:54:27 -0700
Subject: [PATCH 142/224] Report all the js file errors and skip only the nodes
 that are not allowed in js Fixes #11800

---
 src/compiler/program.ts                       | 219 +++++++++---------
 .../reference/decoratorInJsFile.errors.txt    |  13 ++
 .../reference/decoratorInJsFile.symbols       |  12 -
 .../reference/decoratorInJsFile.types         |  14 --
 .../reference/decoratorInJsFile1.errors.txt   |  11 +-
 .../getJavaScriptSyntacticDiagnostics02.ts    |   7 +
 6 files changed, 133 insertions(+), 143 deletions(-)
 create mode 100644 tests/baselines/reference/decoratorInJsFile.errors.txt
 delete mode 100644 tests/baselines/reference/decoratorInJsFile.symbols
 delete mode 100644 tests/baselines/reference/decoratorInJsFile.types

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 1eeeded5d363d..06476d29fbeda 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -773,48 +773,89 @@ namespace ts {
         function getJavaScriptSyntacticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
             return runWithCancellationToken(() => {
                 const diagnostics: Diagnostic[] = [];
+                let parent: Node = sourceFile;
                 walk(sourceFile);
 
                 return diagnostics;
 
-                function walk(node: Node): boolean {
-                    if (!node) {
-                        return false;
+                function walk(node: Node) {
+                    // Return directly from the case if the given node doesnt want to visit each child
+                    // Otherwise break to visit each child
+
+                    switch (parent.kind) {
+                        case SyntaxKind.Parameter:
+                        case SyntaxKind.PropertyDeclaration:
+                            if ((<ParameterDeclaration | PropertyDeclaration>parent).questionToken === node) {
+                                diagnostics.push(createDiagnosticForNode(node, Diagnostics._0_can_only_be_used_in_a_ts_file, "?"));
+                                return;
+                            }
+
+                        // Pass through
+                        case SyntaxKind.MethodDeclaration:
+                        case SyntaxKind.MethodSignature:
+                        case SyntaxKind.Constructor:
+                        case SyntaxKind.GetAccessor:
+                        case SyntaxKind.SetAccessor:
+                        case SyntaxKind.FunctionExpression:
+                        case SyntaxKind.FunctionDeclaration:
+                        case SyntaxKind.ArrowFunction:
+                        case SyntaxKind.FunctionDeclaration:
+                        case SyntaxKind.VariableDeclaration:
+                            // type annotation
+                            if ((<FunctionLikeDeclaration | VariableDeclaration | ParameterDeclaration | PropertyDeclaration>parent).type === node) {
+                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.types_can_only_be_used_in_a_ts_file));
+                                return;
+                            }
                     }
 
                     switch (node.kind) {
                         case SyntaxKind.ImportEqualsDeclaration:
                             diagnostics.push(createDiagnosticForNode(node, Diagnostics.import_can_only_be_used_in_a_ts_file));
-                            return true;
+                            return;
                         case SyntaxKind.ExportAssignment:
                             if ((<ExportAssignment>node).isExportEquals) {
                                 diagnostics.push(createDiagnosticForNode(node, Diagnostics.export_can_only_be_used_in_a_ts_file));
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.ClassDeclaration:
-                            let classDeclaration = <ClassDeclaration>node;
-                            if (checkModifiers(classDeclaration.modifiers) ||
-                                checkTypeParameters(classDeclaration.typeParameters)) {
-                                return true;
+                                return;
                             }
                             break;
                         case SyntaxKind.HeritageClause:
                             let heritageClause = <HeritageClause>node;
                             if (heritageClause.token === SyntaxKind.ImplementsKeyword) {
                                 diagnostics.push(createDiagnosticForNode(node, Diagnostics.implements_clauses_can_only_be_used_in_a_ts_file));
-                                return true;
+                                return;
                             }
                             break;
                         case SyntaxKind.InterfaceDeclaration:
                             diagnostics.push(createDiagnosticForNode(node, Diagnostics.interface_declarations_can_only_be_used_in_a_ts_file));
-                            return true;
+                            return;
                         case SyntaxKind.ModuleDeclaration:
                             diagnostics.push(createDiagnosticForNode(node, Diagnostics.module_declarations_can_only_be_used_in_a_ts_file));
-                            return true;
+                            return;
                         case SyntaxKind.TypeAliasDeclaration:
                             diagnostics.push(createDiagnosticForNode(node, Diagnostics.type_aliases_can_only_be_used_in_a_ts_file));
-                            return true;
+                            return;
+                        case SyntaxKind.EnumDeclaration:
+                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.enum_declarations_can_only_be_used_in_a_ts_file));
+                            return;
+                        case SyntaxKind.TypeAssertionExpression:
+                            let typeAssertionExpression = <TypeAssertion>node;
+                            diagnostics.push(createDiagnosticForNode(typeAssertionExpression.type, Diagnostics.type_assertion_expressions_can_only_be_used_in_a_ts_file));
+                            return;
+                    }
+
+                    const prevParent = parent;
+                    parent = node;
+                    forEachChild(node, walk, walkArray);
+                    parent = prevParent;
+                }
+
+                function walkArray(nodes: NodeArray<Node>) {
+                    if (parent.decorators === nodes && !options.experimentalDecorators) {
+                        diagnostics.push(createDiagnosticForNode(parent, Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning));
+                    }
+
+                    switch (parent.kind) {
+                        case SyntaxKind.ClassDeclaration:
                         case SyntaxKind.MethodDeclaration:
                         case SyntaxKind.MethodSignature:
                         case SyntaxKind.Constructor:
@@ -824,124 +865,76 @@ namespace ts {
                         case SyntaxKind.FunctionDeclaration:
                         case SyntaxKind.ArrowFunction:
                         case SyntaxKind.FunctionDeclaration:
-                            const functionDeclaration = <FunctionLikeDeclaration>node;
-                            if (checkModifiers(functionDeclaration.modifiers) ||
-                                checkTypeParameters(functionDeclaration.typeParameters) ||
-                                checkTypeAnnotation(functionDeclaration.type)) {
-                                return true;
+                            // Check type parameters
+                            if (nodes === (<ClassDeclaration | FunctionLikeDeclaration>parent).typeParameters) {
+                                diagnostics.push(createDiagnosticForNodeArray(nodes, Diagnostics.type_parameter_declarations_can_only_be_used_in_a_ts_file));
+                                return;
                             }
-                            break;
+                        // pass through
                         case SyntaxKind.VariableStatement:
-                            const variableStatement = <VariableStatement>node;
-                            if (checkModifiers(variableStatement.modifiers)) {
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.VariableDeclaration:
-                            const variableDeclaration = <VariableDeclaration>node;
-                            if (checkTypeAnnotation(variableDeclaration.type)) {
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.CallExpression:
-                        case SyntaxKind.NewExpression:
-                            const expression = <CallExpression>node;
-                            if (expression.typeArguments && expression.typeArguments.length > 0) {
-                                const start = expression.typeArguments.pos;
-                                diagnostics.push(createFileDiagnostic(sourceFile, start, expression.typeArguments.end - start,
-                                    Diagnostics.type_arguments_can_only_be_used_in_a_ts_file));
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.Parameter:
-                            const parameter = <ParameterDeclaration>node;
-                            if (parameter.modifiers) {
-                                const start = parameter.modifiers.pos;
-                                diagnostics.push(createFileDiagnostic(sourceFile, start, parameter.modifiers.end - start,
-                                    Diagnostics.parameter_modifiers_can_only_be_used_in_a_ts_file));
-                                return true;
-                            }
-                            if (parameter.questionToken) {
-                                diagnostics.push(createDiagnosticForNode(parameter.questionToken, Diagnostics._0_can_only_be_used_in_a_ts_file, "?"));
-                                return true;
-                            }
-                            if (parameter.type) {
-                                diagnostics.push(createDiagnosticForNode(parameter.type, Diagnostics.types_can_only_be_used_in_a_ts_file));
-                                return true;
+                            // Check modifiers
+                            if (nodes === (<ClassDeclaration | FunctionLikeDeclaration | VariableStatement>parent).modifiers) {
+                                return checkModifiers(<NodeArray<Modifier>>nodes);
                             }
                             break;
                         case SyntaxKind.PropertyDeclaration:
-                            const propertyDeclaration = <PropertyDeclaration>node;
-                            if (propertyDeclaration.modifiers) {
-                                for (const modifier of propertyDeclaration.modifiers) {
+                            // Check modifiers of property declaration
+                            if (nodes === (<PropertyDeclaration>parent).modifiers) {
+                                for (const modifier of <NodeArray<Modifier>>nodes) {
                                     if (modifier.kind !== SyntaxKind.StaticKeyword) {
                                         diagnostics.push(createDiagnosticForNode(modifier, Diagnostics._0_can_only_be_used_in_a_ts_file, tokenToString(modifier.kind)));
-                                        return true;
                                     }
                                 }
+                                return;
                             }
-                            if (checkTypeAnnotation((<PropertyDeclaration>node).type)) {
-                                return true;
+                            break;
+                        case SyntaxKind.Parameter:
+                            // Check modifiers of parameter declaration
+                            if (nodes === (<ParameterDeclaration>parent).modifiers) {
+                                diagnostics.push(createDiagnosticForNodeArray(nodes, Diagnostics.parameter_modifiers_can_only_be_used_in_a_ts_file));
+                                return;
                             }
                             break;
-                        case SyntaxKind.EnumDeclaration:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.enum_declarations_can_only_be_used_in_a_ts_file));
-                            return true;
-                        case SyntaxKind.TypeAssertionExpression:
-                            let typeAssertionExpression = <TypeAssertion>node;
-                            diagnostics.push(createDiagnosticForNode(typeAssertionExpression.type, Diagnostics.type_assertion_expressions_can_only_be_used_in_a_ts_file));
-                            return true;
-                        case SyntaxKind.Decorator:
-                            if (!options.experimentalDecorators) {
-                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning));
+                        case SyntaxKind.CallExpression:
+                        case SyntaxKind.NewExpression:
+                        case SyntaxKind.ExpressionWithTypeArguments:
+                            // Check type arguments
+                            if (nodes === (<CallExpression | NewExpression | ExpressionWithTypeArguments>parent).typeArguments) {
+                                diagnostics.push(createDiagnosticForNodeArray(nodes, Diagnostics.type_arguments_can_only_be_used_in_a_ts_file));
+                                return;
                             }
-                            return true;
+                            break;
                     }
 
-                    return forEachChild(node, walk);
-                }
-
-                function checkTypeParameters(typeParameters: NodeArray<TypeParameterDeclaration>): boolean {
-                    if (typeParameters) {
-                        const start = typeParameters.pos;
-                        diagnostics.push(createFileDiagnostic(sourceFile, start, typeParameters.end - start, Diagnostics.type_parameter_declarations_can_only_be_used_in_a_ts_file));
-                        return true;
+                    for (const node of nodes) {
+                        walk(node);
                     }
-                    return false;
                 }
 
-                function checkTypeAnnotation(type: TypeNode): boolean {
-                    if (type) {
-                        diagnostics.push(createDiagnosticForNode(type, Diagnostics.types_can_only_be_used_in_a_ts_file));
-                        return true;
-                    }
-
-                    return false;
-                }
-
-                function checkModifiers(modifiers: NodeArray<Modifier>): boolean {
-                    if (modifiers) {
-                        for (const modifier of modifiers) {
-                            switch (modifier.kind) {
-                                case SyntaxKind.PublicKeyword:
-                                case SyntaxKind.PrivateKeyword:
-                                case SyntaxKind.ProtectedKeyword:
-                                case SyntaxKind.ReadonlyKeyword:
-                                case SyntaxKind.DeclareKeyword:
-                                    diagnostics.push(createDiagnosticForNode(modifier, Diagnostics._0_can_only_be_used_in_a_ts_file, tokenToString(modifier.kind)));
-                                    return true;
-
-                                // These are all legal modifiers.
-                                case SyntaxKind.StaticKeyword:
-                                case SyntaxKind.ExportKeyword:
-                                case SyntaxKind.ConstKeyword:
-                                case SyntaxKind.DefaultKeyword:
-                                case SyntaxKind.AbstractKeyword:
-                            }
+                function checkModifiers(modifiers: NodeArray<Modifier>) {
+                    for (const modifier of modifiers) {
+                        switch (modifier.kind) {
+                            case SyntaxKind.PublicKeyword:
+                            case SyntaxKind.PrivateKeyword:
+                            case SyntaxKind.ProtectedKeyword:
+                            case SyntaxKind.ReadonlyKeyword:
+                            case SyntaxKind.DeclareKeyword:
+                                diagnostics.push(createDiagnosticForNode(modifier, Diagnostics._0_can_only_be_used_in_a_ts_file, tokenToString(modifier.kind)));
+                                break;
+
+                            // These are all legal modifiers.
+                            case SyntaxKind.StaticKeyword:
+                            case SyntaxKind.ExportKeyword:
+                            case SyntaxKind.ConstKeyword:
+                            case SyntaxKind.DefaultKeyword:
+                            case SyntaxKind.AbstractKeyword:
                         }
                     }
+                }
 
-                    return false;
+                function createDiagnosticForNodeArray(nodes: NodeArray<Node>, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number): Diagnostic {
+                    const start = nodes.pos;
+                    return createFileDiagnostic(sourceFile, start, nodes.end - start, message, arg0, arg1, arg2);
                 }
 
                 // Since these are syntactic diagnostics, parent might not have been set
diff --git a/tests/baselines/reference/decoratorInJsFile.errors.txt b/tests/baselines/reference/decoratorInJsFile.errors.txt
new file mode 100644
index 0000000000000..93bd5143b7486
--- /dev/null
+++ b/tests/baselines/reference/decoratorInJsFile.errors.txt
@@ -0,0 +1,13 @@
+tests/cases/compiler/a.js(4,12): error TS8010: 'types' can only be used in a .ts file.
+
+
+==== tests/cases/compiler/a.js (1 errors) ====
+    
+    @SomeDecorator
+    class SomeClass {
+        foo(x: number) {
+               ~~~~~~
+!!! error TS8010: 'types' can only be used in a .ts file.
+    
+        }
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/decoratorInJsFile.symbols b/tests/baselines/reference/decoratorInJsFile.symbols
deleted file mode 100644
index 1ad477095c1be..0000000000000
--- a/tests/baselines/reference/decoratorInJsFile.symbols
+++ /dev/null
@@ -1,12 +0,0 @@
-=== tests/cases/compiler/a.js ===
-
-@SomeDecorator
-class SomeClass {
->SomeClass : Symbol(SomeClass, Decl(a.js, 0, 0))
-
-    foo(x: number) {
->foo : Symbol(SomeClass.foo, Decl(a.js, 2, 17))
->x : Symbol(x, Decl(a.js, 3, 8))
-
-    }
-}
diff --git a/tests/baselines/reference/decoratorInJsFile.types b/tests/baselines/reference/decoratorInJsFile.types
deleted file mode 100644
index 494039794604b..0000000000000
--- a/tests/baselines/reference/decoratorInJsFile.types
+++ /dev/null
@@ -1,14 +0,0 @@
-=== tests/cases/compiler/a.js ===
-
-@SomeDecorator
->SomeDecorator : any
-
-class SomeClass {
->SomeClass : SomeClass
-
-    foo(x: number) {
->foo : (x: number) => void
->x : number
-
-    }
-}
diff --git a/tests/baselines/reference/decoratorInJsFile1.errors.txt b/tests/baselines/reference/decoratorInJsFile1.errors.txt
index a90aa922f96a7..f4422c0c2d9b8 100644
--- a/tests/baselines/reference/decoratorInJsFile1.errors.txt
+++ b/tests/baselines/reference/decoratorInJsFile1.errors.txt
@@ -1,13 +1,16 @@
-tests/cases/compiler/a.js(2,1): error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option to remove this warning.
+tests/cases/compiler/a.js(3,7): error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option to remove this warning.
+tests/cases/compiler/a.js(4,12): error TS8010: 'types' can only be used in a .ts file.
 
 
-==== tests/cases/compiler/a.js (1 errors) ====
+==== tests/cases/compiler/a.js (2 errors) ====
     
     @SomeDecorator
-    ~~~~~~~~~~~~~~
-!!! error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option to remove this warning.
     class SomeClass {
+          ~~~~~~~~~
+!!! error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option to remove this warning.
         foo(x: number) {
+               ~~~~~~
+!!! error TS8010: 'types' can only be used in a .ts file.
     
         }
     }
\ No newline at end of file
diff --git a/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts b/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts
index dd9becad10b70..a19d170217cb9 100644
--- a/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts
+++ b/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts
@@ -15,6 +15,13 @@ verify.getSyntacticDiagnostics(`[
     "category": "error",
     "code": 8010
   },
+  {
+    "message": "\'types\' can only be used in a .ts file.",
+    "start": 52,
+    "length": 6,
+    "category": "error",
+    "code": 8010
+  },
   {
     "message": "Variable declaration expected.",
     "start": 67,

From 663985eed06ed2878a03eda57cd919c97a022571 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Tue, 1 Nov 2016 16:59:53 -0700
Subject: [PATCH 143/224] Fix 'keyof any' to produce 'string | number'

---
 src/compiler/checker.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 31aab95ffb1bc..2f264eaa2b13d 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5713,7 +5713,7 @@ namespace ts {
 
         function getIndexType(type: Type): Type {
             return type.flags & TypeFlags.TypeParameter ? getIndexTypeForTypeParameter(<TypeParameter>type) :
-                getIndexInfoOfType(type, IndexKind.String) ? stringOrNumberType :
+                type.flags & TypeFlags.Any || getIndexInfoOfType(type, IndexKind.String) ? stringOrNumberType :
                 getIndexInfoOfType(type, IndexKind.Number) ? getUnionType([numberType, getLiteralTypeFromPropertyNames(type)]) :
                 getLiteralTypeFromPropertyNames(type);
         }

From 6b94bae437b96614266c38b653aee3aad541d865 Mon Sep 17 00:00:00 2001
From: Mohamed Hegazy <mhegazy@microsoft.com>
Date: Tue, 1 Nov 2016 17:03:56 -0700
Subject: [PATCH 144/224] Fix #11396: Make error message referene `Promise`
 explicitly (#11982)

* Simplify the checking for async function return type

* Fix https://github.com/Microsoft/TypeScript/issues/11396: Make error message referene `Promise` explicitly
---
 src/compiler/checker.ts                       | 131 +++++++-----------
 src/compiler/diagnosticMessages.json          |   4 +
 .../asyncFunctionNoReturnType.errors.txt      |   4 +-
 3 files changed, 57 insertions(+), 82 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 627bf3bb2e297..744d23a3657a1 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -13073,7 +13073,7 @@ namespace ts {
         function createPromiseReturnType(func: FunctionLikeDeclaration, promisedType: Type) {
             const promiseType = createPromiseType(promisedType);
             if (promiseType === emptyObjectType) {
-                error(func, Diagnostics.An_async_function_or_method_must_have_a_valid_awaitable_return_type);
+                error(func, Diagnostics.An_async_function_or_method_must_return_a_Promise_Make_sure_you_have_a_declaration_for_Promise_or_include_ES2015_in_your_lib_option);
                 return unknownType;
             }
 
@@ -15515,36 +15515,6 @@ namespace ts {
             }
         }
 
-        /**
-         * Checks that the return type provided is an instantiation of the global Promise<T> type
-         * and returns the awaited type of the return type.
-         *
-         * @param returnType The return type of a FunctionLikeDeclaration
-         * @param location The node on which to report the error.
-         */
-        function checkCorrectPromiseType(returnType: Type, location: Node, diagnostic: DiagnosticMessage, typeName?: string) {
-            if (returnType === unknownType) {
-                // The return type already had some other error, so we ignore and return
-                // the unknown type.
-                return unknownType;
-            }
-
-            const globalPromiseType = getGlobalPromiseType();
-            if (globalPromiseType === emptyGenericType
-                || globalPromiseType === getTargetType(returnType)) {
-                // Either we couldn't resolve the global promise type, which would have already
-                // reported an error, or we could resolve it and the return type is a valid type
-                // reference to the global type. In either case, we return the awaited type for
-                // the return type.
-                return checkAwaitedType(returnType, location, Diagnostics.An_async_function_or_method_must_have_a_valid_awaitable_return_type);
-            }
-
-            // The promise type was not a valid type reference to the global promise type, so we
-            // report an error and return the unknown type.
-            error(location, diagnostic, typeName);
-            return unknownType;
-        }
-
         /**
          * Checks the return type of an async function to ensure it is a compatible
          * Promise implementation.
@@ -15559,11 +15529,6 @@ namespace ts {
          * @param node The signature to check
          */
         function checkAsyncFunctionReturnType(node: FunctionLikeDeclaration): Type {
-            if (languageVersion >= ScriptTarget.ES2015) {
-                const returnType = getTypeFromTypeNode(node.type);
-                return checkCorrectPromiseType(returnType, node.type, Diagnostics.The_return_type_of_an_async_function_or_method_must_be_the_global_Promise_T_type);
-            }
-
             // As part of our emit for an async function, we will need to emit the entity name of
             // the return type annotation as an expression. To meet the necessary runtime semantics
             // for __awaiter, we must also check that the type of the declaration (e.g. the static
@@ -15588,61 +15553,67 @@ namespace ts {
             //      then<U>(...): Promise<U>;
             //  }
             //
+            const returnType = getTypeFromTypeNode(node.type);
 
-            // Always mark the type node as referenced if it points to a value
-            markTypeNodeAsReferenced(node.type);
-
-            const promiseConstructorName = getEntityNameFromTypeNode(node.type);
-            const promiseType = getTypeFromTypeNode(node.type);
-            if (promiseType === unknownType) {
-                if (!compilerOptions.isolatedModules) {
-                    if (promiseConstructorName) {
-                        error(node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, entityNameToString(promiseConstructorName));
-                    }
-                    else {
-                        error(node.type, Diagnostics.An_async_function_or_method_must_have_a_valid_awaitable_return_type);
-                    }
+            if (languageVersion >= ScriptTarget.ES2015) {
+                if (returnType === unknownType) {
+                    return unknownType;
+                }
+                const globalPromiseType = getGlobalPromiseType();
+                if (globalPromiseType !== emptyGenericType && globalPromiseType !== getTargetType(returnType)) {
+                    // The promise type was not a valid type reference to the global promise type, so we
+                    // report an error and return the unknown type.
+                    error(node.type, Diagnostics.The_return_type_of_an_async_function_or_method_must_be_the_global_Promise_T_type);
+                    return unknownType;
                 }
-                return unknownType;
             }
+            else {
+                // Always mark the type node as referenced if it points to a value
+                markTypeNodeAsReferenced(node.type);
 
-            if (promiseConstructorName === undefined) {
-                error(node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, typeToString(promiseType));
-                return unknownType;
-            }
+                if (returnType === unknownType) {
+                    return unknownType;
+                }
 
-            const promiseConstructorSymbol = resolveEntityName(promiseConstructorName, SymbolFlags.Value, /*ignoreErrors*/ true);
-            const promiseConstructorType = promiseConstructorSymbol ? getTypeOfSymbol(promiseConstructorSymbol) : unknownType;
-            if (promiseConstructorType === unknownType) {
-                error(node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, entityNameToString(promiseConstructorName));
-                return unknownType;
-            }
+                const promiseConstructorName = getEntityNameFromTypeNode(node.type);
+                if (promiseConstructorName === undefined) {
+                    error(node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, typeToString(returnType));
+                    return unknownType;
+                }
 
-            const globalPromiseConstructorLikeType = getGlobalPromiseConstructorLikeType();
-            if (globalPromiseConstructorLikeType === emptyObjectType) {
-                // If we couldn't resolve the global PromiseConstructorLike type we cannot verify
-                // compatibility with __awaiter.
-                error(node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, entityNameToString(promiseConstructorName));
-                return unknownType;
-            }
+                const promiseConstructorSymbol = resolveEntityName(promiseConstructorName, SymbolFlags.Value, /*ignoreErrors*/ true);
+                const promiseConstructorType = promiseConstructorSymbol ? getTypeOfSymbol(promiseConstructorSymbol) : unknownType;
+                if (promiseConstructorType === unknownType) {
+                    error(node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, entityNameToString(promiseConstructorName));
+                    return unknownType;
+                }
 
-            if (!checkTypeAssignableTo(promiseConstructorType, globalPromiseConstructorLikeType, node.type,
-                Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value)) {
-                return unknownType;
-            }
+                const globalPromiseConstructorLikeType = getGlobalPromiseConstructorLikeType();
+                if (globalPromiseConstructorLikeType === emptyObjectType) {
+                    // If we couldn't resolve the global PromiseConstructorLike type we cannot verify
+                    // compatibility with __awaiter.
+                    error(node.type, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, entityNameToString(promiseConstructorName));
+                    return unknownType;
+                }
 
-            // Verify there is no local declaration that could collide with the promise constructor.
-            const rootName = promiseConstructorName && getFirstIdentifier(promiseConstructorName);
-            const collidingSymbol = getSymbol(node.locals, rootName.text, SymbolFlags.Value);
-            if (collidingSymbol) {
-                error(collidingSymbol.valueDeclaration, Diagnostics.Duplicate_identifier_0_Compiler_uses_declaration_1_to_support_async_functions,
-                    rootName.text,
-                    entityNameToString(promiseConstructorName));
-                return unknownType;
+                if (!checkTypeAssignableTo(promiseConstructorType, globalPromiseConstructorLikeType, node.type,
+                    Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value)) {
+                    return unknownType;
+                }
+
+                // Verify there is no local declaration that could collide with the promise constructor.
+                const rootName = promiseConstructorName && getFirstIdentifier(promiseConstructorName);
+                const collidingSymbol = getSymbol(node.locals, rootName.text, SymbolFlags.Value);
+                if (collidingSymbol) {
+                    error(collidingSymbol.valueDeclaration, Diagnostics.Duplicate_identifier_0_Compiler_uses_declaration_1_to_support_async_functions,
+                        rootName.text,
+                        entityNameToString(promiseConstructorName));
+                    return unknownType;
+                }
             }
 
             // Get and return the awaited type of the return type.
-            return checkAwaitedType(promiseType, node, Diagnostics.An_async_function_or_method_must_have_a_valid_awaitable_return_type);
+            return checkAwaitedType(returnType, node, Diagnostics.An_async_function_or_method_must_have_a_valid_awaitable_return_type);
         }
 
         /** Check a decorator */
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 7d5a141884371..3b873cf35c04e 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1967,6 +1967,10 @@
         "category": "Error",
         "code": 2696
     },
+    "An async function or method must return a 'Promise'. Make sure you have a declaration for 'Promise' or include 'ES2015' in your `--lib` option.": {
+        "category": "Error",
+        "code": 2697
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
diff --git a/tests/baselines/reference/asyncFunctionNoReturnType.errors.txt b/tests/baselines/reference/asyncFunctionNoReturnType.errors.txt
index 599bf41a7f2b5..89a61ff648fd3 100644
--- a/tests/baselines/reference/asyncFunctionNoReturnType.errors.txt
+++ b/tests/baselines/reference/asyncFunctionNoReturnType.errors.txt
@@ -1,5 +1,5 @@
 error TS2318: Cannot find global type 'Promise'.
-tests/cases/compiler/asyncFunctionNoReturnType.ts(1,1): error TS1057: An async function or method must have a valid awaitable return type.
+tests/cases/compiler/asyncFunctionNoReturnType.ts(1,1): error TS2697: An async function or method must return a 'Promise'. Make sure you have a declaration for 'Promise' or include 'ES2015' in your `--lib` option.
 tests/cases/compiler/asyncFunctionNoReturnType.ts(1,1): error TS7030: Not all code paths return a value.
 tests/cases/compiler/asyncFunctionNoReturnType.ts(2,9): error TS2304: Cannot find name 'window'.
 tests/cases/compiler/asyncFunctionNoReturnType.ts(3,9): error TS7030: Not all code paths return a value.
@@ -9,7 +9,7 @@ tests/cases/compiler/asyncFunctionNoReturnType.ts(3,9): error TS7030: Not all co
 ==== tests/cases/compiler/asyncFunctionNoReturnType.ts (4 errors) ====
     async () => {
     ~~~~~~~~~~~~~
-!!! error TS1057: An async function or method must have a valid awaitable return type.
+!!! error TS2697: An async function or method must return a 'Promise'. Make sure you have a declaration for 'Promise' or include 'ES2015' in your `--lib` option.
     ~~~~~~~~~~~~~
 !!! error TS7030: Not all code paths return a value.
         if (window)

From 70fc25a45a57d11b316809fe95ab15dc5bac181f Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Wed, 2 Nov 2016 09:02:05 -0700
Subject: [PATCH 145/224] Minor fixes

---
 src/compiler/checker.ts | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 2f264eaa2b13d..7d0dd5892764d 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5761,6 +5761,9 @@ namespace ts {
                 }
             }
             if (isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.ESSymbol)) {
+                if (isTypeAny(objectType)) {
+                    return anyType;
+                }
                 const indexInfo = isTypeAnyOrAllConstituentTypesHaveKind(indexType, TypeFlags.NumberLike) && getIndexInfoOfType(objectType, IndexKind.Number) ||
                     getIndexInfoOfType(objectType, IndexKind.String) ||
                     undefined;
@@ -5772,7 +5775,7 @@ namespace ts {
                     return indexInfo.type;
                 }
                 if (accessExpression && !isConstEnumObjectType(objectType)) {
-                    if (compilerOptions.noImplicitAny && !compilerOptions.suppressImplicitAnyIndexErrors && !isTypeAny(objectType)) {
+                    if (compilerOptions.noImplicitAny && !compilerOptions.suppressImplicitAnyIndexErrors) {
                         if (getIndexTypeOfType(objectType, IndexKind.Number)) {
                             error(accessExpression.argumentExpression, Diagnostics.Element_implicitly_has_an_any_type_because_index_expression_is_not_of_type_number);
                         }
@@ -5789,7 +5792,7 @@ namespace ts {
                     error(indexNode, Diagnostics.Property_0_does_not_exist_on_type_1, (<LiteralType>indexType).text, typeToString(objectType));
                 }
                 else if (indexType.flags & (TypeFlags.String | TypeFlags.Number)) {
-                    error(accessNode, Diagnostics.Type_0_has_no_matching_index_signature_for_type_1, typeToString(objectType), typeToString(indexType));
+                    error(indexNode, Diagnostics.Type_0_has_no_matching_index_signature_for_type_1, typeToString(objectType), typeToString(indexType));
                 }
                 else {
                     error(indexNode, Diagnostics.Type_0_cannot_be_used_as_an_index_type, typeToString(indexType));

From 4bbe29ab733dcc2449d81f22b19be7f798cfb856 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Wed, 2 Nov 2016 09:13:45 -0700
Subject: [PATCH 146/224] Adding tests

---
 .../reference/keyofAndIndexedAccess.js        | 350 +++++++++
 .../reference/keyofAndIndexedAccess.symbols   | 577 +++++++++++++++
 .../reference/keyofAndIndexedAccess.types     | 681 ++++++++++++++++++
 .../keyofAndIndexedAccessErrors.errors.txt    | 138 ++++
 .../reference/keyofAndIndexedAccessErrors.js  |  90 +++
 .../types/keyof/keyofAndIndexedAccess.ts      | 167 +++++
 .../keyof/keyofAndIndexedAccessErrors.ts      |  68 ++
 7 files changed, 2071 insertions(+)
 create mode 100644 tests/baselines/reference/keyofAndIndexedAccess.js
 create mode 100644 tests/baselines/reference/keyofAndIndexedAccess.symbols
 create mode 100644 tests/baselines/reference/keyofAndIndexedAccess.types
 create mode 100644 tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt
 create mode 100644 tests/baselines/reference/keyofAndIndexedAccessErrors.js
 create mode 100644 tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts
 create mode 100644 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts

diff --git a/tests/baselines/reference/keyofAndIndexedAccess.js b/tests/baselines/reference/keyofAndIndexedAccess.js
new file mode 100644
index 0000000000000..5d986f3e89203
--- /dev/null
+++ b/tests/baselines/reference/keyofAndIndexedAccess.js
@@ -0,0 +1,350 @@
+//// [keyofAndIndexedAccess.ts]
+
+class Shape {
+    name: string;
+    width: number;
+    height: number;
+    visible: boolean;
+}
+
+class Item {
+    name: string;
+    price: number;
+}
+
+class Options {
+    visible: "yes" | "no";
+}
+
+type Dictionary<T> = { [x: string]: T };
+
+const enum E { A, B, C }
+
+type K00 = keyof any;  // string | number
+type K01 = keyof string;  // number | "toString" | "charAt" | ...
+type K02 = keyof number;  // "toString" | "toFixed" | "toExponential" | ...
+type K03 = keyof boolean;  // "valueOf"
+type K04 = keyof void;  // never
+type K05 = keyof undefined;  // never
+type K06 = keyof null;  // never
+type K07 = keyof never;  // never
+
+type K10 = keyof Shape;  // "name" | "width" | "height" | "visible"
+type K11 = keyof Shape[];  // number | "length" | "toString" | ...
+type K12 = keyof Dictionary<Shape>;  // string | number
+type K13 = keyof {};  // never
+type K14 = keyof Object;  // "constructor" | "toString" | ...
+type K15 = keyof E;  // "toString" | "toFixed" | "toExponential" | ...
+type K16 = keyof [string, number];  // number | "0" | "1" | "length" | "toString" | ...
+type K17 = keyof (Shape | Item);  // "name"
+type K18 = keyof (Shape & Item);  // "name" | "width" | "height" | "visible" | "price"
+
+type KeyOf<T> = keyof T;
+
+type K20 = KeyOf<Shape>;  // "name" | "width" | "height" | "visible"
+type K21 = KeyOf<Dictionary<Shape>>;  // string | number
+
+type NAME = "name";
+type WIDTH_OR_HEIGHT = "width" | "height";
+
+type Q10 = Shape["name"];  // string
+type Q11 = Shape["width" | "height"];  // number
+type Q12 = Shape["name" | "visible"];  // string | boolean
+
+type Q20 = Shape[NAME];  // string
+type Q21 = Shape[WIDTH_OR_HEIGHT];  // number
+
+type Q30 = [string, number][0];  // string
+type Q31 = [string, number][1];  // number
+type Q32 = [string, number][2];  // string | number
+type Q33 = [string, number][E.A];  // string
+type Q34 = [string, number][E.B];  // number
+type Q35 = [string, number][E.C];  // string | number
+type Q36 = [string, number]["0"];  // string
+type Q37 = [string, number]["1"];  // string
+
+type Q40 = (Shape | Options)["visible"];  // boolean | "yes" | "no"
+type Q41 = (Shape & Options)["visible"];  // true & "yes" | true & "no" | false & "yes" | false & "no"
+
+type Q50 = Dictionary<Shape>["howdy"];  // Shape
+type Q51 = Dictionary<Shape>[123];  // Shape
+type Q52 = Dictionary<Shape>[E.B];  // Shape
+
+declare let cond: boolean;
+
+function getProperty<T, K extends keyof T>(obj: T, key: K) {
+    return obj[key];
+}
+
+function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+    obj[key] = value;
+}
+
+function f10(shape: Shape) {
+    let name = getProperty(shape, "name");  // string
+    let widthOrHeight = getProperty(shape, cond ? "width" : "height");  // number
+    let nameOrVisible = getProperty(shape, cond ? "name" : "visible");  // string | boolean
+    setProperty(shape, "name", "rectangle");
+    setProperty(shape, cond ? "width" : "height", 10);
+    setProperty(shape, cond ? "name" : "visible", true);  // Technically not safe
+}
+
+function f11(a: Shape[]) {
+    let len = getProperty(a, "length");  // number
+    let shape = getProperty(a, 1000);    // Shape
+    setProperty(a, 1000, getProperty(a, 1001));
+}
+
+function f12(t: [Shape, boolean]) {
+    let len = getProperty(t, "length");
+    let s1 = getProperty(t, 0);    // Shape
+    let s2 = getProperty(t, "0");  // Shape
+    let b1 = getProperty(t, 1);    // boolean
+    let b2 = getProperty(t, "1");  // boolean
+    let x1 = getProperty(t, 2);    // Shape | boolean
+}
+
+function f13(foo: any, bar: any) {
+    let x = getProperty(foo, "x");  // any
+    let y = getProperty(foo, 100);  // any
+    let z = getProperty(foo, bar);  // any
+}
+
+class Component<PropType> {
+    props: PropType;
+    getProperty<K extends keyof PropType>(key: K) {
+        return this.props[key];
+    }
+    setProperty<K extends keyof PropType>(key: K, value: PropType[K]) {
+        this.props[key] = value;
+    }
+}
+
+function f20(component: Component<Shape>) {
+    let name = component.getProperty("name");  // string
+    let widthOrHeight = component.getProperty(cond ? "width" : "height");  // number
+    let nameOrVisible = component.getProperty(cond ? "name" : "visible");  // string | boolean
+    component.setProperty("name", "rectangle");
+    component.setProperty(cond ? "width" : "height", 10)
+    component.setProperty(cond ? "name" : "visible", true);  // Technically not safe
+}
+
+function pluck<T, K extends keyof T>(array: T[], key: K) {
+    return array.map(x => x[key]);
+}
+
+function f30(shapes: Shape[]) {
+    let names = pluck(shapes, "name");    // string[]
+    let widths = pluck(shapes, "width");  // number[]
+    let nameOrVisibles = pluck(shapes, cond ? "name" : "visible");  // (string | boolean)[]
+}
+
+function f31<K extends keyof Shape>(key: K) {
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+    return shape[key];  // Shape[K]
+}
+
+function f32<K extends "width" | "height">(key: K) {
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+    return shape[key];  // Shape[K]
+}
+
+class C {
+    public x: string;
+    protected y: string;
+    private z: string;
+}
+
+// Indexed access expressions have always permitted access to private and protected members.
+// For consistency we also permit such access in indexed access types.
+function f40(c: C) {
+    type X = C["x"];
+    type Y = C["y"];
+    type Z = C["z"];
+    let x: X = c["x"];
+    let y: Y = c["y"];
+    let z: Z = c["z"];
+}
+
+//// [keyofAndIndexedAccess.js]
+var Shape = (function () {
+    function Shape() {
+    }
+    return Shape;
+}());
+var Item = (function () {
+    function Item() {
+    }
+    return Item;
+}());
+var Options = (function () {
+    function Options() {
+    }
+    return Options;
+}());
+function getProperty(obj, key) {
+    return obj[key];
+}
+function setProperty(obj, key, value) {
+    obj[key] = value;
+}
+function f10(shape) {
+    var name = getProperty(shape, "name"); // string
+    var widthOrHeight = getProperty(shape, cond ? "width" : "height"); // number
+    var nameOrVisible = getProperty(shape, cond ? "name" : "visible"); // string | boolean
+    setProperty(shape, "name", "rectangle");
+    setProperty(shape, cond ? "width" : "height", 10);
+    setProperty(shape, cond ? "name" : "visible", true); // Technically not safe
+}
+function f11(a) {
+    var len = getProperty(a, "length"); // number
+    var shape = getProperty(a, 1000); // Shape
+    setProperty(a, 1000, getProperty(a, 1001));
+}
+function f12(t) {
+    var len = getProperty(t, "length");
+    var s1 = getProperty(t, 0); // Shape
+    var s2 = getProperty(t, "0"); // Shape
+    var b1 = getProperty(t, 1); // boolean
+    var b2 = getProperty(t, "1"); // boolean
+    var x1 = getProperty(t, 2); // Shape | boolean
+}
+function f13(foo, bar) {
+    var x = getProperty(foo, "x"); // any
+    var y = getProperty(foo, 100); // any
+    var z = getProperty(foo, bar); // any
+}
+var Component = (function () {
+    function Component() {
+    }
+    Component.prototype.getProperty = function (key) {
+        return this.props[key];
+    };
+    Component.prototype.setProperty = function (key, value) {
+        this.props[key] = value;
+    };
+    return Component;
+}());
+function f20(component) {
+    var name = component.getProperty("name"); // string
+    var widthOrHeight = component.getProperty(cond ? "width" : "height"); // number
+    var nameOrVisible = component.getProperty(cond ? "name" : "visible"); // string | boolean
+    component.setProperty("name", "rectangle");
+    component.setProperty(cond ? "width" : "height", 10);
+    component.setProperty(cond ? "name" : "visible", true); // Technically not safe
+}
+function pluck(array, key) {
+    return array.map(function (x) { return x[key]; });
+}
+function f30(shapes) {
+    var names = pluck(shapes, "name"); // string[]
+    var widths = pluck(shapes, "width"); // number[]
+    var nameOrVisibles = pluck(shapes, cond ? "name" : "visible"); // (string | boolean)[]
+}
+function f31(key) {
+    var shape = { name: "foo", width: 5, height: 10, visible: true };
+    return shape[key]; // Shape[K]
+}
+function f32(key) {
+    var shape = { name: "foo", width: 5, height: 10, visible: true };
+    return shape[key]; // Shape[K]
+}
+var C = (function () {
+    function C() {
+    }
+    return C;
+}());
+// Indexed access expressions have always permitted access to private and protected members.
+// For consistency we also permit such access in indexed access types.
+function f40(c) {
+    var x = c["x"];
+    var y = c["y"];
+    var z = c["z"];
+}
+
+
+//// [keyofAndIndexedAccess.d.ts]
+declare class Shape {
+    name: string;
+    width: number;
+    height: number;
+    visible: boolean;
+}
+declare class Item {
+    name: string;
+    price: number;
+}
+declare class Options {
+    visible: "yes" | "no";
+}
+declare type Dictionary<T> = {
+    [x: string]: T;
+};
+declare const enum E {
+    A = 0,
+    B = 1,
+    C = 2,
+}
+declare type K00 = keyof any;
+declare type K01 = keyof string;
+declare type K02 = keyof number;
+declare type K03 = keyof boolean;
+declare type K04 = keyof void;
+declare type K05 = keyof undefined;
+declare type K06 = keyof null;
+declare type K07 = keyof never;
+declare type K10 = keyof Shape;
+declare type K11 = keyof Shape[];
+declare type K12 = keyof Dictionary<Shape>;
+declare type K13 = keyof {};
+declare type K14 = keyof Object;
+declare type K15 = keyof E;
+declare type K16 = keyof [string, number];
+declare type K17 = keyof (Shape | Item);
+declare type K18 = keyof (Shape & Item);
+declare type KeyOf<T> = keyof T;
+declare type K20 = KeyOf<Shape>;
+declare type K21 = KeyOf<Dictionary<Shape>>;
+declare type NAME = "name";
+declare type WIDTH_OR_HEIGHT = "width" | "height";
+declare type Q10 = Shape["name"];
+declare type Q11 = Shape["width" | "height"];
+declare type Q12 = Shape["name" | "visible"];
+declare type Q20 = Shape[NAME];
+declare type Q21 = Shape[WIDTH_OR_HEIGHT];
+declare type Q30 = [string, number][0];
+declare type Q31 = [string, number][1];
+declare type Q32 = [string, number][2];
+declare type Q33 = [string, number][E.A];
+declare type Q34 = [string, number][E.B];
+declare type Q35 = [string, number][E.C];
+declare type Q36 = [string, number]["0"];
+declare type Q37 = [string, number]["1"];
+declare type Q40 = (Shape | Options)["visible"];
+declare type Q41 = (Shape & Options)["visible"];
+declare type Q50 = Dictionary<Shape>["howdy"];
+declare type Q51 = Dictionary<Shape>[123];
+declare type Q52 = Dictionary<Shape>[E.B];
+declare let cond: boolean;
+declare function getProperty<T, K extends keyof T>(obj: T, key: K): T[K];
+declare function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]): void;
+declare function f10(shape: Shape): void;
+declare function f11(a: Shape[]): void;
+declare function f12(t: [Shape, boolean]): void;
+declare function f13(foo: any, bar: any): void;
+declare class Component<PropType> {
+    props: PropType;
+    getProperty<K extends keyof PropType>(key: K): PropType[K];
+    setProperty<K extends keyof PropType>(key: K, value: PropType[K]): void;
+}
+declare function f20(component: Component<Shape>): void;
+declare function pluck<T, K extends keyof T>(array: T[], key: K): T[K][];
+declare function f30(shapes: Shape[]): void;
+declare function f31<K extends keyof Shape>(key: K): Shape[K];
+declare function f32<K extends "width" | "height">(key: K): Shape[K];
+declare class C {
+    x: string;
+    protected y: string;
+    private z;
+}
+declare function f40(c: C): void;
diff --git a/tests/baselines/reference/keyofAndIndexedAccess.symbols b/tests/baselines/reference/keyofAndIndexedAccess.symbols
new file mode 100644
index 0000000000000..d3e967ed12504
--- /dev/null
+++ b/tests/baselines/reference/keyofAndIndexedAccess.symbols
@@ -0,0 +1,577 @@
+=== tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts ===
+
+class Shape {
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    name: string;
+>name : Symbol(Shape.name, Decl(keyofAndIndexedAccess.ts, 1, 13))
+
+    width: number;
+>width : Symbol(Shape.width, Decl(keyofAndIndexedAccess.ts, 2, 17))
+
+    height: number;
+>height : Symbol(Shape.height, Decl(keyofAndIndexedAccess.ts, 3, 18))
+
+    visible: boolean;
+>visible : Symbol(Shape.visible, Decl(keyofAndIndexedAccess.ts, 4, 19))
+}
+
+class Item {
+>Item : Symbol(Item, Decl(keyofAndIndexedAccess.ts, 6, 1))
+
+    name: string;
+>name : Symbol(Item.name, Decl(keyofAndIndexedAccess.ts, 8, 12))
+
+    price: number;
+>price : Symbol(Item.price, Decl(keyofAndIndexedAccess.ts, 9, 17))
+}
+
+class Options {
+>Options : Symbol(Options, Decl(keyofAndIndexedAccess.ts, 11, 1))
+
+    visible: "yes" | "no";
+>visible : Symbol(Options.visible, Decl(keyofAndIndexedAccess.ts, 13, 15))
+}
+
+type Dictionary<T> = { [x: string]: T };
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 17, 16))
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 17, 24))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 17, 16))
+
+const enum E { A, B, C }
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+>A : Symbol(E.A, Decl(keyofAndIndexedAccess.ts, 19, 14))
+>B : Symbol(E.B, Decl(keyofAndIndexedAccess.ts, 19, 17))
+>C : Symbol(E.C, Decl(keyofAndIndexedAccess.ts, 19, 20))
+
+type K00 = keyof any;  // string | number
+>K00 : Symbol(K00, Decl(keyofAndIndexedAccess.ts, 19, 24))
+
+type K01 = keyof string;  // number | "toString" | "charAt" | ...
+>K01 : Symbol(K01, Decl(keyofAndIndexedAccess.ts, 21, 21))
+
+type K02 = keyof number;  // "toString" | "toFixed" | "toExponential" | ...
+>K02 : Symbol(K02, Decl(keyofAndIndexedAccess.ts, 22, 24))
+
+type K03 = keyof boolean;  // "valueOf"
+>K03 : Symbol(K03, Decl(keyofAndIndexedAccess.ts, 23, 24))
+
+type K04 = keyof void;  // never
+>K04 : Symbol(K04, Decl(keyofAndIndexedAccess.ts, 24, 25))
+
+type K05 = keyof undefined;  // never
+>K05 : Symbol(K05, Decl(keyofAndIndexedAccess.ts, 25, 22))
+
+type K06 = keyof null;  // never
+>K06 : Symbol(K06, Decl(keyofAndIndexedAccess.ts, 26, 27))
+
+type K07 = keyof never;  // never
+>K07 : Symbol(K07, Decl(keyofAndIndexedAccess.ts, 27, 22))
+
+type K10 = keyof Shape;  // "name" | "width" | "height" | "visible"
+>K10 : Symbol(K10, Decl(keyofAndIndexedAccess.ts, 28, 23))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type K11 = keyof Shape[];  // number | "length" | "toString" | ...
+>K11 : Symbol(K11, Decl(keyofAndIndexedAccess.ts, 30, 23))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type K12 = keyof Dictionary<Shape>;  // string | number
+>K12 : Symbol(K12, Decl(keyofAndIndexedAccess.ts, 31, 25))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type K13 = keyof {};  // never
+>K13 : Symbol(K13, Decl(keyofAndIndexedAccess.ts, 32, 35))
+
+type K14 = keyof Object;  // "constructor" | "toString" | ...
+>K14 : Symbol(K14, Decl(keyofAndIndexedAccess.ts, 33, 20))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+type K15 = keyof E;  // "toString" | "toFixed" | "toExponential" | ...
+>K15 : Symbol(K15, Decl(keyofAndIndexedAccess.ts, 34, 24))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+
+type K16 = keyof [string, number];  // number | "0" | "1" | "length" | "toString" | ...
+>K16 : Symbol(K16, Decl(keyofAndIndexedAccess.ts, 35, 19))
+
+type K17 = keyof (Shape | Item);  // "name"
+>K17 : Symbol(K17, Decl(keyofAndIndexedAccess.ts, 36, 34))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>Item : Symbol(Item, Decl(keyofAndIndexedAccess.ts, 6, 1))
+
+type K18 = keyof (Shape & Item);  // "name" | "width" | "height" | "visible" | "price"
+>K18 : Symbol(K18, Decl(keyofAndIndexedAccess.ts, 37, 32))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>Item : Symbol(Item, Decl(keyofAndIndexedAccess.ts, 6, 1))
+
+type KeyOf<T> = keyof T;
+>KeyOf : Symbol(KeyOf, Decl(keyofAndIndexedAccess.ts, 38, 32))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 40, 11))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 40, 11))
+
+type K20 = KeyOf<Shape>;  // "name" | "width" | "height" | "visible"
+>K20 : Symbol(K20, Decl(keyofAndIndexedAccess.ts, 40, 24))
+>KeyOf : Symbol(KeyOf, Decl(keyofAndIndexedAccess.ts, 38, 32))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type K21 = KeyOf<Dictionary<Shape>>;  // string | number
+>K21 : Symbol(K21, Decl(keyofAndIndexedAccess.ts, 42, 24))
+>KeyOf : Symbol(KeyOf, Decl(keyofAndIndexedAccess.ts, 38, 32))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type NAME = "name";
+>NAME : Symbol(NAME, Decl(keyofAndIndexedAccess.ts, 43, 36))
+
+type WIDTH_OR_HEIGHT = "width" | "height";
+>WIDTH_OR_HEIGHT : Symbol(WIDTH_OR_HEIGHT, Decl(keyofAndIndexedAccess.ts, 45, 19))
+
+type Q10 = Shape["name"];  // string
+>Q10 : Symbol(Q10, Decl(keyofAndIndexedAccess.ts, 46, 42))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type Q11 = Shape["width" | "height"];  // number
+>Q11 : Symbol(Q11, Decl(keyofAndIndexedAccess.ts, 48, 25))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type Q12 = Shape["name" | "visible"];  // string | boolean
+>Q12 : Symbol(Q12, Decl(keyofAndIndexedAccess.ts, 49, 37))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type Q20 = Shape[NAME];  // string
+>Q20 : Symbol(Q20, Decl(keyofAndIndexedAccess.ts, 50, 37))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>NAME : Symbol(NAME, Decl(keyofAndIndexedAccess.ts, 43, 36))
+
+type Q21 = Shape[WIDTH_OR_HEIGHT];  // number
+>Q21 : Symbol(Q21, Decl(keyofAndIndexedAccess.ts, 52, 23))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>WIDTH_OR_HEIGHT : Symbol(WIDTH_OR_HEIGHT, Decl(keyofAndIndexedAccess.ts, 45, 19))
+
+type Q30 = [string, number][0];  // string
+>Q30 : Symbol(Q30, Decl(keyofAndIndexedAccess.ts, 53, 34))
+
+type Q31 = [string, number][1];  // number
+>Q31 : Symbol(Q31, Decl(keyofAndIndexedAccess.ts, 55, 31))
+
+type Q32 = [string, number][2];  // string | number
+>Q32 : Symbol(Q32, Decl(keyofAndIndexedAccess.ts, 56, 31))
+
+type Q33 = [string, number][E.A];  // string
+>Q33 : Symbol(Q33, Decl(keyofAndIndexedAccess.ts, 57, 31))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+>A : Symbol(E.A, Decl(keyofAndIndexedAccess.ts, 19, 14))
+
+type Q34 = [string, number][E.B];  // number
+>Q34 : Symbol(Q34, Decl(keyofAndIndexedAccess.ts, 58, 33))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+>B : Symbol(E.B, Decl(keyofAndIndexedAccess.ts, 19, 17))
+
+type Q35 = [string, number][E.C];  // string | number
+>Q35 : Symbol(Q35, Decl(keyofAndIndexedAccess.ts, 59, 33))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+>C : Symbol(E.C, Decl(keyofAndIndexedAccess.ts, 19, 20))
+
+type Q36 = [string, number]["0"];  // string
+>Q36 : Symbol(Q36, Decl(keyofAndIndexedAccess.ts, 60, 33))
+
+type Q37 = [string, number]["1"];  // string
+>Q37 : Symbol(Q37, Decl(keyofAndIndexedAccess.ts, 61, 33))
+
+type Q40 = (Shape | Options)["visible"];  // boolean | "yes" | "no"
+>Q40 : Symbol(Q40, Decl(keyofAndIndexedAccess.ts, 62, 33))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>Options : Symbol(Options, Decl(keyofAndIndexedAccess.ts, 11, 1))
+
+type Q41 = (Shape & Options)["visible"];  // true & "yes" | true & "no" | false & "yes" | false & "no"
+>Q41 : Symbol(Q41, Decl(keyofAndIndexedAccess.ts, 64, 40))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>Options : Symbol(Options, Decl(keyofAndIndexedAccess.ts, 11, 1))
+
+type Q50 = Dictionary<Shape>["howdy"];  // Shape
+>Q50 : Symbol(Q50, Decl(keyofAndIndexedAccess.ts, 65, 40))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type Q51 = Dictionary<Shape>[123];  // Shape
+>Q51 : Symbol(Q51, Decl(keyofAndIndexedAccess.ts, 67, 38))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type Q52 = Dictionary<Shape>[E.B];  // Shape
+>Q52 : Symbol(Q52, Decl(keyofAndIndexedAccess.ts, 68, 34))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+>B : Symbol(E.B, Decl(keyofAndIndexedAccess.ts, 19, 17))
+
+declare let cond: boolean;
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+function getProperty<T, K extends keyof T>(obj: T, key: K) {
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 73, 21))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 73, 23))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 73, 21))
+>obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 73, 43))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 73, 21))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 73, 50))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 73, 23))
+
+    return obj[key];
+>obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 73, 43))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 73, 50))
+}
+
+function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 77, 21))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 77, 23))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 77, 21))
+>obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 77, 43))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 77, 21))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 77, 50))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 77, 23))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 77, 58))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 77, 21))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 77, 23))
+
+    obj[key] = value;
+>obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 77, 43))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 77, 50))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 77, 58))
+}
+
+function f10(shape: Shape) {
+>f10 : Symbol(f10, Decl(keyofAndIndexedAccess.ts, 79, 1))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    let name = getProperty(shape, "name");  // string
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 82, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+
+    let widthOrHeight = getProperty(shape, cond ? "width" : "height");  // number
+>widthOrHeight : Symbol(widthOrHeight, Decl(keyofAndIndexedAccess.ts, 83, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+    let nameOrVisible = getProperty(shape, cond ? "name" : "visible");  // string | boolean
+>nameOrVisible : Symbol(nameOrVisible, Decl(keyofAndIndexedAccess.ts, 84, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+    setProperty(shape, "name", "rectangle");
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+
+    setProperty(shape, cond ? "width" : "height", 10);
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+    setProperty(shape, cond ? "name" : "visible", true);  // Technically not safe
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+}
+
+function f11(a: Shape[]) {
+>f11 : Symbol(f11, Decl(keyofAndIndexedAccess.ts, 88, 1))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    let len = getProperty(a, "length");  // number
+>len : Symbol(len, Decl(keyofAndIndexedAccess.ts, 91, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+
+    let shape = getProperty(a, 1000);    // Shape
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 92, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+
+    setProperty(a, 1000, getProperty(a, 1001));
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+}
+
+function f12(t: [Shape, boolean]) {
+>f12 : Symbol(f12, Decl(keyofAndIndexedAccess.ts, 94, 1))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    let len = getProperty(t, "length");
+>len : Symbol(len, Decl(keyofAndIndexedAccess.ts, 97, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+
+    let s1 = getProperty(t, 0);    // Shape
+>s1 : Symbol(s1, Decl(keyofAndIndexedAccess.ts, 98, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+
+    let s2 = getProperty(t, "0");  // Shape
+>s2 : Symbol(s2, Decl(keyofAndIndexedAccess.ts, 99, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+
+    let b1 = getProperty(t, 1);    // boolean
+>b1 : Symbol(b1, Decl(keyofAndIndexedAccess.ts, 100, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+
+    let b2 = getProperty(t, "1");  // boolean
+>b2 : Symbol(b2, Decl(keyofAndIndexedAccess.ts, 101, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+
+    let x1 = getProperty(t, 2);    // Shape | boolean
+>x1 : Symbol(x1, Decl(keyofAndIndexedAccess.ts, 102, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+}
+
+function f13(foo: any, bar: any) {
+>f13 : Symbol(f13, Decl(keyofAndIndexedAccess.ts, 103, 1))
+>foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 105, 13))
+>bar : Symbol(bar, Decl(keyofAndIndexedAccess.ts, 105, 22))
+
+    let x = getProperty(foo, "x");  // any
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 106, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 105, 13))
+
+    let y = getProperty(foo, 100);  // any
+>y : Symbol(y, Decl(keyofAndIndexedAccess.ts, 107, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 105, 13))
+
+    let z = getProperty(foo, bar);  // any
+>z : Symbol(z, Decl(keyofAndIndexedAccess.ts, 108, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 105, 13))
+>bar : Symbol(bar, Decl(keyofAndIndexedAccess.ts, 105, 22))
+}
+
+class Component<PropType> {
+>Component : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 109, 1))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
+
+    props: PropType;
+>props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
+
+    getProperty<K extends keyof PropType>(key: K) {
+>getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 113, 16))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 113, 42))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 113, 16))
+
+        return this.props[key];
+>this.props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
+>this : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 109, 1))
+>props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 113, 42))
+    }
+    setProperty<K extends keyof PropType>(key: K, value: PropType[K]) {
+>setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 116, 16))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 116, 42))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 116, 16))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 116, 49))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 116, 16))
+
+        this.props[key] = value;
+>this.props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
+>this : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 109, 1))
+>props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 116, 42))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 116, 49))
+    }
+}
+
+function f20(component: Component<Shape>) {
+>f20 : Symbol(f20, Decl(keyofAndIndexedAccess.ts, 119, 1))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>Component : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 109, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    let name = component.getProperty("name");  // string
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 122, 7))
+>component.getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+
+    let widthOrHeight = component.getProperty(cond ? "width" : "height");  // number
+>widthOrHeight : Symbol(widthOrHeight, Decl(keyofAndIndexedAccess.ts, 123, 7))
+>component.getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+    let nameOrVisible = component.getProperty(cond ? "name" : "visible");  // string | boolean
+>nameOrVisible : Symbol(nameOrVisible, Decl(keyofAndIndexedAccess.ts, 124, 7))
+>component.getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+    component.setProperty("name", "rectangle");
+>component.setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+
+    component.setProperty(cond ? "width" : "height", 10)
+>component.setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+    component.setProperty(cond ? "name" : "visible", true);  // Technically not safe
+>component.setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+}
+
+function pluck<T, K extends keyof T>(array: T[], key: K) {
+>pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 128, 1))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 130, 15))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 130, 17))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 130, 15))
+>array : Symbol(array, Decl(keyofAndIndexedAccess.ts, 130, 37))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 130, 15))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 130, 48))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 130, 17))
+
+    return array.map(x => x[key]);
+>array.map : Symbol(Array.map, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>array : Symbol(array, Decl(keyofAndIndexedAccess.ts, 130, 37))
+>map : Symbol(Array.map, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 131, 21))
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 131, 21))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 130, 48))
+}
+
+function f30(shapes: Shape[]) {
+>f30 : Symbol(f30, Decl(keyofAndIndexedAccess.ts, 132, 1))
+>shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 134, 13))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    let names = pluck(shapes, "name");    // string[]
+>names : Symbol(names, Decl(keyofAndIndexedAccess.ts, 135, 7))
+>pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 128, 1))
+>shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 134, 13))
+
+    let widths = pluck(shapes, "width");  // number[]
+>widths : Symbol(widths, Decl(keyofAndIndexedAccess.ts, 136, 7))
+>pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 128, 1))
+>shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 134, 13))
+
+    let nameOrVisibles = pluck(shapes, cond ? "name" : "visible");  // (string | boolean)[]
+>nameOrVisibles : Symbol(nameOrVisibles, Decl(keyofAndIndexedAccess.ts, 137, 7))
+>pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 128, 1))
+>shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 134, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+}
+
+function f31<K extends keyof Shape>(key: K) {
+>f31 : Symbol(f31, Decl(keyofAndIndexedAccess.ts, 138, 1))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 140, 13))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 140, 36))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 140, 13))
+
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 141, 9))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 141, 26))
+>width : Symbol(width, Decl(keyofAndIndexedAccess.ts, 141, 39))
+>height : Symbol(height, Decl(keyofAndIndexedAccess.ts, 141, 49))
+>visible : Symbol(visible, Decl(keyofAndIndexedAccess.ts, 141, 61))
+
+    return shape[key];  // Shape[K]
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 141, 9))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 140, 36))
+}
+
+function f32<K extends "width" | "height">(key: K) {
+>f32 : Symbol(f32, Decl(keyofAndIndexedAccess.ts, 143, 1))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 145, 13))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 145, 43))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 145, 13))
+
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 146, 9))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 146, 26))
+>width : Symbol(width, Decl(keyofAndIndexedAccess.ts, 146, 39))
+>height : Symbol(height, Decl(keyofAndIndexedAccess.ts, 146, 49))
+>visible : Symbol(visible, Decl(keyofAndIndexedAccess.ts, 146, 61))
+
+    return shape[key];  // Shape[K]
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 146, 9))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 145, 43))
+}
+
+class C {
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+
+    public x: string;
+>x : Symbol(C.x, Decl(keyofAndIndexedAccess.ts, 150, 9))
+
+    protected y: string;
+>y : Symbol(C.y, Decl(keyofAndIndexedAccess.ts, 151, 21))
+
+    private z: string;
+>z : Symbol(C.z, Decl(keyofAndIndexedAccess.ts, 152, 24))
+}
+
+// Indexed access expressions have always permitted access to private and protected members.
+// For consistency we also permit such access in indexed access types.
+function f40(c: C) {
+>f40 : Symbol(f40, Decl(keyofAndIndexedAccess.ts, 154, 1))
+>c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 158, 13))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+
+    type X = C["x"];
+>X : Symbol(X, Decl(keyofAndIndexedAccess.ts, 158, 20))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+
+    type Y = C["y"];
+>Y : Symbol(Y, Decl(keyofAndIndexedAccess.ts, 159, 20))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+
+    type Z = C["z"];
+>Z : Symbol(Z, Decl(keyofAndIndexedAccess.ts, 160, 20))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+
+    let x: X = c["x"];
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 162, 7))
+>X : Symbol(X, Decl(keyofAndIndexedAccess.ts, 158, 20))
+>c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 158, 13))
+>"x" : Symbol(C.x, Decl(keyofAndIndexedAccess.ts, 150, 9))
+
+    let y: Y = c["y"];
+>y : Symbol(y, Decl(keyofAndIndexedAccess.ts, 163, 7))
+>Y : Symbol(Y, Decl(keyofAndIndexedAccess.ts, 159, 20))
+>c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 158, 13))
+>"y" : Symbol(C.y, Decl(keyofAndIndexedAccess.ts, 151, 21))
+
+    let z: Z = c["z"];
+>z : Symbol(z, Decl(keyofAndIndexedAccess.ts, 164, 7))
+>Z : Symbol(Z, Decl(keyofAndIndexedAccess.ts, 160, 20))
+>c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 158, 13))
+>"z" : Symbol(C.z, Decl(keyofAndIndexedAccess.ts, 152, 24))
+}
diff --git a/tests/baselines/reference/keyofAndIndexedAccess.types b/tests/baselines/reference/keyofAndIndexedAccess.types
new file mode 100644
index 0000000000000..74c06a2535da7
--- /dev/null
+++ b/tests/baselines/reference/keyofAndIndexedAccess.types
@@ -0,0 +1,681 @@
+=== tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts ===
+
+class Shape {
+>Shape : Shape
+
+    name: string;
+>name : string
+
+    width: number;
+>width : number
+
+    height: number;
+>height : number
+
+    visible: boolean;
+>visible : boolean
+}
+
+class Item {
+>Item : Item
+
+    name: string;
+>name : string
+
+    price: number;
+>price : number
+}
+
+class Options {
+>Options : Options
+
+    visible: "yes" | "no";
+>visible : "yes" | "no"
+}
+
+type Dictionary<T> = { [x: string]: T };
+>Dictionary : { [x: string]: T; }
+>T : T
+>x : string
+>T : T
+
+const enum E { A, B, C }
+>E : E
+>A : E.A
+>B : E.B
+>C : E.C
+
+type K00 = keyof any;  // string | number
+>K00 : string | number
+
+type K01 = keyof string;  // number | "toString" | "charAt" | ...
+>K01 : number | "length" | "toString" | "concat" | "slice" | "indexOf" | "lastIndexOf" | "charAt" | "charCodeAt" | "localeCompare" | "match" | "replace" | "search" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "substr" | "valueOf"
+
+type K02 = keyof number;  // "toString" | "toFixed" | "toExponential" | ...
+>K02 : "toString" | "toLocaleString" | "valueOf" | "toFixed" | "toExponential" | "toPrecision"
+
+type K03 = keyof boolean;  // "valueOf"
+>K03 : "valueOf"
+
+type K04 = keyof void;  // never
+>K04 : never
+
+type K05 = keyof undefined;  // never
+>K05 : never
+
+type K06 = keyof null;  // never
+>K06 : never
+>null : null
+
+type K07 = keyof never;  // never
+>K07 : never
+
+type K10 = keyof Shape;  // "name" | "width" | "height" | "visible"
+>K10 : "name" | "width" | "height" | "visible"
+>Shape : Shape
+
+type K11 = keyof Shape[];  // number | "length" | "toString" | ...
+>K11 : number | "length" | "toString" | "toLocaleString" | "push" | "pop" | "concat" | "join" | "reverse" | "shift" | "slice" | "sort" | "splice" | "unshift" | "indexOf" | "lastIndexOf" | "every" | "some" | "forEach" | "map" | "filter" | "reduce" | "reduceRight"
+>Shape : Shape
+
+type K12 = keyof Dictionary<Shape>;  // string | number
+>K12 : string | number
+>Dictionary : { [x: string]: T; }
+>Shape : Shape
+
+type K13 = keyof {};  // never
+>K13 : never
+
+type K14 = keyof Object;  // "constructor" | "toString" | ...
+>K14 : "toString" | "toLocaleString" | "valueOf" | "constructor" | "hasOwnProperty" | "isPrototypeOf" | "propertyIsEnumerable"
+>Object : Object
+
+type K15 = keyof E;  // "toString" | "toFixed" | "toExponential" | ...
+>K15 : "toString" | "toLocaleString" | "valueOf" | "toFixed" | "toExponential" | "toPrecision"
+>E : E
+
+type K16 = keyof [string, number];  // number | "0" | "1" | "length" | "toString" | ...
+>K16 : number | "0" | "1" | "length" | "toString" | "toLocaleString" | "push" | "pop" | "concat" | "join" | "reverse" | "shift" | "slice" | "sort" | "splice" | "unshift" | "indexOf" | "lastIndexOf" | "every" | "some" | "forEach" | "map" | "filter" | "reduce" | "reduceRight"
+
+type K17 = keyof (Shape | Item);  // "name"
+>K17 : "name"
+>Shape : Shape
+>Item : Item
+
+type K18 = keyof (Shape & Item);  // "name" | "width" | "height" | "visible" | "price"
+>K18 : "name" | "width" | "height" | "visible" | "price"
+>Shape : Shape
+>Item : Item
+
+type KeyOf<T> = keyof T;
+>KeyOf : keyof T
+>T : T
+>T : T
+
+type K20 = KeyOf<Shape>;  // "name" | "width" | "height" | "visible"
+>K20 : "name" | "width" | "height" | "visible"
+>KeyOf : keyof T
+>Shape : Shape
+
+type K21 = KeyOf<Dictionary<Shape>>;  // string | number
+>K21 : string | number
+>KeyOf : keyof T
+>Dictionary : { [x: string]: T; }
+>Shape : Shape
+
+type NAME = "name";
+>NAME : "name"
+
+type WIDTH_OR_HEIGHT = "width" | "height";
+>WIDTH_OR_HEIGHT : "width" | "height"
+
+type Q10 = Shape["name"];  // string
+>Q10 : string
+>Shape : Shape
+
+type Q11 = Shape["width" | "height"];  // number
+>Q11 : number
+>Shape : Shape
+
+type Q12 = Shape["name" | "visible"];  // string | boolean
+>Q12 : string | boolean
+>Shape : Shape
+
+type Q20 = Shape[NAME];  // string
+>Q20 : string
+>Shape : Shape
+>NAME : "name"
+
+type Q21 = Shape[WIDTH_OR_HEIGHT];  // number
+>Q21 : number
+>Shape : Shape
+>WIDTH_OR_HEIGHT : "width" | "height"
+
+type Q30 = [string, number][0];  // string
+>Q30 : string
+
+type Q31 = [string, number][1];  // number
+>Q31 : number
+
+type Q32 = [string, number][2];  // string | number
+>Q32 : string | number
+
+type Q33 = [string, number][E.A];  // string
+>Q33 : string
+>E : any
+>A : E.A
+
+type Q34 = [string, number][E.B];  // number
+>Q34 : number
+>E : any
+>B : E.B
+
+type Q35 = [string, number][E.C];  // string | number
+>Q35 : string | number
+>E : any
+>C : E.C
+
+type Q36 = [string, number]["0"];  // string
+>Q36 : string
+
+type Q37 = [string, number]["1"];  // string
+>Q37 : number
+
+type Q40 = (Shape | Options)["visible"];  // boolean | "yes" | "no"
+>Q40 : boolean | "yes" | "no"
+>Shape : Shape
+>Options : Options
+
+type Q41 = (Shape & Options)["visible"];  // true & "yes" | true & "no" | false & "yes" | false & "no"
+>Q41 : (true & "yes") | (true & "no") | (false & "yes") | (false & "no")
+>Shape : Shape
+>Options : Options
+
+type Q50 = Dictionary<Shape>["howdy"];  // Shape
+>Q50 : Shape
+>Dictionary : { [x: string]: T; }
+>Shape : Shape
+
+type Q51 = Dictionary<Shape>[123];  // Shape
+>Q51 : Shape
+>Dictionary : { [x: string]: T; }
+>Shape : Shape
+
+type Q52 = Dictionary<Shape>[E.B];  // Shape
+>Q52 : Shape
+>Dictionary : { [x: string]: T; }
+>Shape : Shape
+>E : any
+>B : E.B
+
+declare let cond: boolean;
+>cond : boolean
+
+function getProperty<T, K extends keyof T>(obj: T, key: K) {
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>T : T
+>K : K
+>T : T
+>obj : T
+>T : T
+>key : K
+>K : K
+
+    return obj[key];
+>obj[key] : T[K]
+>obj : T
+>key : K
+}
+
+function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+>setProperty : <T, K extends keyof T>(obj: T, key: K, value: T[K]) => void
+>T : T
+>K : K
+>T : T
+>obj : T
+>T : T
+>key : K
+>K : K
+>value : T[K]
+>T : T
+>K : K
+
+    obj[key] = value;
+>obj[key] = value : T[K]
+>obj[key] : T[K]
+>obj : T
+>key : K
+>value : T[K]
+}
+
+function f10(shape: Shape) {
+>f10 : (shape: Shape) => void
+>shape : Shape
+>Shape : Shape
+
+    let name = getProperty(shape, "name");  // string
+>name : string
+>getProperty(shape, "name") : string
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>shape : Shape
+>"name" : "name"
+
+    let widthOrHeight = getProperty(shape, cond ? "width" : "height");  // number
+>widthOrHeight : number
+>getProperty(shape, cond ? "width" : "height") : number
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>shape : Shape
+>cond ? "width" : "height" : "width" | "height"
+>cond : boolean
+>"width" : "width"
+>"height" : "height"
+
+    let nameOrVisible = getProperty(shape, cond ? "name" : "visible");  // string | boolean
+>nameOrVisible : string | boolean
+>getProperty(shape, cond ? "name" : "visible") : string | boolean
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>shape : Shape
+>cond ? "name" : "visible" : "name" | "visible"
+>cond : boolean
+>"name" : "name"
+>"visible" : "visible"
+
+    setProperty(shape, "name", "rectangle");
+>setProperty(shape, "name", "rectangle") : void
+>setProperty : <T, K extends keyof T>(obj: T, key: K, value: T[K]) => void
+>shape : Shape
+>"name" : "name"
+>"rectangle" : "rectangle"
+
+    setProperty(shape, cond ? "width" : "height", 10);
+>setProperty(shape, cond ? "width" : "height", 10) : void
+>setProperty : <T, K extends keyof T>(obj: T, key: K, value: T[K]) => void
+>shape : Shape
+>cond ? "width" : "height" : "width" | "height"
+>cond : boolean
+>"width" : "width"
+>"height" : "height"
+>10 : 10
+
+    setProperty(shape, cond ? "name" : "visible", true);  // Technically not safe
+>setProperty(shape, cond ? "name" : "visible", true) : void
+>setProperty : <T, K extends keyof T>(obj: T, key: K, value: T[K]) => void
+>shape : Shape
+>cond ? "name" : "visible" : "name" | "visible"
+>cond : boolean
+>"name" : "name"
+>"visible" : "visible"
+>true : true
+}
+
+function f11(a: Shape[]) {
+>f11 : (a: Shape[]) => void
+>a : Shape[]
+>Shape : Shape
+
+    let len = getProperty(a, "length");  // number
+>len : number
+>getProperty(a, "length") : number
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>a : Shape[]
+>"length" : "length"
+
+    let shape = getProperty(a, 1000);    // Shape
+>shape : Shape
+>getProperty(a, 1000) : Shape
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>a : Shape[]
+>1000 : 1000
+
+    setProperty(a, 1000, getProperty(a, 1001));
+>setProperty(a, 1000, getProperty(a, 1001)) : void
+>setProperty : <T, K extends keyof T>(obj: T, key: K, value: T[K]) => void
+>a : Shape[]
+>1000 : 1000
+>getProperty(a, 1001) : Shape
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>a : Shape[]
+>1001 : 1001
+}
+
+function f12(t: [Shape, boolean]) {
+>f12 : (t: [Shape, boolean]) => void
+>t : [Shape, boolean]
+>Shape : Shape
+
+    let len = getProperty(t, "length");
+>len : number
+>getProperty(t, "length") : number
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>t : [Shape, boolean]
+>"length" : "length"
+
+    let s1 = getProperty(t, 0);    // Shape
+>s1 : Shape
+>getProperty(t, 0) : Shape
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>t : [Shape, boolean]
+>0 : 0
+
+    let s2 = getProperty(t, "0");  // Shape
+>s2 : Shape
+>getProperty(t, "0") : Shape
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>t : [Shape, boolean]
+>"0" : "0"
+
+    let b1 = getProperty(t, 1);    // boolean
+>b1 : boolean
+>getProperty(t, 1) : boolean
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>t : [Shape, boolean]
+>1 : 1
+
+    let b2 = getProperty(t, "1");  // boolean
+>b2 : boolean
+>getProperty(t, "1") : boolean
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>t : [Shape, boolean]
+>"1" : "1"
+
+    let x1 = getProperty(t, 2);    // Shape | boolean
+>x1 : boolean | Shape
+>getProperty(t, 2) : boolean | Shape
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>t : [Shape, boolean]
+>2 : 2
+}
+
+function f13(foo: any, bar: any) {
+>f13 : (foo: any, bar: any) => void
+>foo : any
+>bar : any
+
+    let x = getProperty(foo, "x");  // any
+>x : any
+>getProperty(foo, "x") : any
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>foo : any
+>"x" : "x"
+
+    let y = getProperty(foo, 100);  // any
+>y : any
+>getProperty(foo, 100) : any
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>foo : any
+>100 : 100
+
+    let z = getProperty(foo, bar);  // any
+>z : any
+>getProperty(foo, bar) : any
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>foo : any
+>bar : any
+}
+
+class Component<PropType> {
+>Component : Component<PropType>
+>PropType : PropType
+
+    props: PropType;
+>props : PropType
+>PropType : PropType
+
+    getProperty<K extends keyof PropType>(key: K) {
+>getProperty : <K extends keyof PropType>(key: K) => PropType[K]
+>K : K
+>PropType : PropType
+>key : K
+>K : K
+
+        return this.props[key];
+>this.props[key] : PropType[K]
+>this.props : PropType
+>this : this
+>props : PropType
+>key : K
+    }
+    setProperty<K extends keyof PropType>(key: K, value: PropType[K]) {
+>setProperty : <K extends keyof PropType>(key: K, value: PropType[K]) => void
+>K : K
+>PropType : PropType
+>key : K
+>K : K
+>value : PropType[K]
+>PropType : PropType
+>K : K
+
+        this.props[key] = value;
+>this.props[key] = value : PropType[K]
+>this.props[key] : PropType[K]
+>this.props : PropType
+>this : this
+>props : PropType
+>key : K
+>value : PropType[K]
+    }
+}
+
+function f20(component: Component<Shape>) {
+>f20 : (component: Component<Shape>) => void
+>component : Component<Shape>
+>Component : Component<PropType>
+>Shape : Shape
+
+    let name = component.getProperty("name");  // string
+>name : string
+>component.getProperty("name") : string
+>component.getProperty : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>component : Component<Shape>
+>getProperty : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>"name" : "name"
+
+    let widthOrHeight = component.getProperty(cond ? "width" : "height");  // number
+>widthOrHeight : number
+>component.getProperty(cond ? "width" : "height") : number
+>component.getProperty : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>component : Component<Shape>
+>getProperty : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>cond ? "width" : "height" : "width" | "height"
+>cond : boolean
+>"width" : "width"
+>"height" : "height"
+
+    let nameOrVisible = component.getProperty(cond ? "name" : "visible");  // string | boolean
+>nameOrVisible : string | boolean
+>component.getProperty(cond ? "name" : "visible") : string | boolean
+>component.getProperty : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>component : Component<Shape>
+>getProperty : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>cond ? "name" : "visible" : "name" | "visible"
+>cond : boolean
+>"name" : "name"
+>"visible" : "visible"
+
+    component.setProperty("name", "rectangle");
+>component.setProperty("name", "rectangle") : void
+>component.setProperty : <K extends "name" | "width" | "height" | "visible">(key: K, value: Shape[K]) => void
+>component : Component<Shape>
+>setProperty : <K extends "name" | "width" | "height" | "visible">(key: K, value: Shape[K]) => void
+>"name" : "name"
+>"rectangle" : "rectangle"
+
+    component.setProperty(cond ? "width" : "height", 10)
+>component.setProperty(cond ? "width" : "height", 10) : void
+>component.setProperty : <K extends "name" | "width" | "height" | "visible">(key: K, value: Shape[K]) => void
+>component : Component<Shape>
+>setProperty : <K extends "name" | "width" | "height" | "visible">(key: K, value: Shape[K]) => void
+>cond ? "width" : "height" : "width" | "height"
+>cond : boolean
+>"width" : "width"
+>"height" : "height"
+>10 : 10
+
+    component.setProperty(cond ? "name" : "visible", true);  // Technically not safe
+>component.setProperty(cond ? "name" : "visible", true) : void
+>component.setProperty : <K extends "name" | "width" | "height" | "visible">(key: K, value: Shape[K]) => void
+>component : Component<Shape>
+>setProperty : <K extends "name" | "width" | "height" | "visible">(key: K, value: Shape[K]) => void
+>cond ? "name" : "visible" : "name" | "visible"
+>cond : boolean
+>"name" : "name"
+>"visible" : "visible"
+>true : true
+}
+
+function pluck<T, K extends keyof T>(array: T[], key: K) {
+>pluck : <T, K extends keyof T>(array: T[], key: K) => T[K][]
+>T : T
+>K : K
+>T : T
+>array : T[]
+>T : T
+>key : K
+>K : K
+
+    return array.map(x => x[key]);
+>array.map(x => x[key]) : T[K][]
+>array.map : { <U>(this: [T, T, T, T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U, U, U, U]; <U>(this: [T, T, T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U, U, U]; <U>(this: [T, T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U, U]; <U>(this: [T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U]; <U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): U[]; }
+>array : T[]
+>map : { <U>(this: [T, T, T, T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U, U, U, U]; <U>(this: [T, T, T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U, U, U]; <U>(this: [T, T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U, U]; <U>(this: [T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U]; <U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): U[]; }
+>x => x[key] : (x: T) => T[K]
+>x : T
+>x[key] : T[K]
+>x : T
+>key : K
+}
+
+function f30(shapes: Shape[]) {
+>f30 : (shapes: Shape[]) => void
+>shapes : Shape[]
+>Shape : Shape
+
+    let names = pluck(shapes, "name");    // string[]
+>names : string[]
+>pluck(shapes, "name") : string[]
+>pluck : <T, K extends keyof T>(array: T[], key: K) => T[K][]
+>shapes : Shape[]
+>"name" : "name"
+
+    let widths = pluck(shapes, "width");  // number[]
+>widths : number[]
+>pluck(shapes, "width") : number[]
+>pluck : <T, K extends keyof T>(array: T[], key: K) => T[K][]
+>shapes : Shape[]
+>"width" : "width"
+
+    let nameOrVisibles = pluck(shapes, cond ? "name" : "visible");  // (string | boolean)[]
+>nameOrVisibles : (string | boolean)[]
+>pluck(shapes, cond ? "name" : "visible") : (string | boolean)[]
+>pluck : <T, K extends keyof T>(array: T[], key: K) => T[K][]
+>shapes : Shape[]
+>cond ? "name" : "visible" : "name" | "visible"
+>cond : boolean
+>"name" : "name"
+>"visible" : "visible"
+}
+
+function f31<K extends keyof Shape>(key: K) {
+>f31 : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>K : K
+>Shape : Shape
+>key : K
+>K : K
+
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+>shape : Shape
+>Shape : Shape
+>{ name: "foo", width: 5, height: 10, visible: true } : { name: string; width: number; height: number; visible: true; }
+>name : string
+>"foo" : "foo"
+>width : number
+>5 : 5
+>height : number
+>10 : 10
+>visible : boolean
+>true : true
+
+    return shape[key];  // Shape[K]
+>shape[key] : Shape[K]
+>shape : Shape
+>key : K
+}
+
+function f32<K extends "width" | "height">(key: K) {
+>f32 : <K extends "width" | "height">(key: K) => Shape[K]
+>K : K
+>key : K
+>K : K
+
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+>shape : Shape
+>Shape : Shape
+>{ name: "foo", width: 5, height: 10, visible: true } : { name: string; width: number; height: number; visible: true; }
+>name : string
+>"foo" : "foo"
+>width : number
+>5 : 5
+>height : number
+>10 : 10
+>visible : boolean
+>true : true
+
+    return shape[key];  // Shape[K]
+>shape[key] : Shape[K]
+>shape : Shape
+>key : K
+}
+
+class C {
+>C : C
+
+    public x: string;
+>x : string
+
+    protected y: string;
+>y : string
+
+    private z: string;
+>z : string
+}
+
+// Indexed access expressions have always permitted access to private and protected members.
+// For consistency we also permit such access in indexed access types.
+function f40(c: C) {
+>f40 : (c: C) => void
+>c : C
+>C : C
+
+    type X = C["x"];
+>X : string
+>C : C
+
+    type Y = C["y"];
+>Y : string
+>C : C
+
+    type Z = C["z"];
+>Z : string
+>C : C
+
+    let x: X = c["x"];
+>x : string
+>X : string
+>c["x"] : string
+>c : C
+>"x" : "x"
+
+    let y: Y = c["y"];
+>y : string
+>Y : string
+>c["y"] : string
+>c : C
+>"y" : "y"
+
+    let z: Z = c["z"];
+>z : string
+>Z : string
+>c["z"] : string
+>c : C
+>"z" : "z"
+}
diff --git a/tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt b/tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt
new file mode 100644
index 0000000000000..23b79c16627fc
--- /dev/null
+++ b/tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt
@@ -0,0 +1,138 @@
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(10,18): error TS2304: Cannot find name 'K0'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(20,18): error TS2339: Property 'foo' does not exist on type 'Shape'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(21,18): error TS2339: Property 'foo' does not exist on type 'Shape'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(22,18): error TS2538: Type 'any' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(23,18): error TS2537: Type 'Shape' has no matching index signature for type 'string'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(24,18): error TS2537: Type 'Shape' has no matching index signature for type 'number'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(25,18): error TS2538: Type 'boolean' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(26,18): error TS2538: Type 'void' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(27,18): error TS2538: Type 'undefined' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(28,18): error TS2538: Type '{ x: string; }' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(29,18): error TS2537: Type 'Shape' has no matching index signature for type 'string'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(30,18): error TS2538: Type 'string & number' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(31,18): error TS2537: Type 'Shape' has no matching index signature for type 'string'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(35,21): error TS2537: Type 'string[]' has no matching index signature for type 'string'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(36,21): error TS2538: Type 'boolean' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(41,31): error TS2538: Type 'boolean' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(46,16): error TS2538: Type 'boolean' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(63,33): error TS2345: Argument of type '"size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(64,33): error TS2345: Argument of type '"name" | "size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+  Type '"size"' is not assignable to type '"name" | "width" | "height" | "visible"'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(66,24): error TS2345: Argument of type '"size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(67,24): error TS2345: Argument of type '"name" | "size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+  Type '"size"' is not assignable to type '"name" | "width" | "height" | "visible"'.
+
+
+==== tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts (21 errors) ====
+    class Shape {
+        name: string;
+        width: number;
+        height: number;
+        visible: boolean;
+    }
+    
+    type Dictionary<T> = { [x: string]: T };
+    
+    type T00 = keyof K0;  // Error
+                     ~~
+!!! error TS2304: Cannot find name 'K0'.
+    
+    type T01 = keyof Object;
+    type T02 = keyof keyof Object;
+    type T03 = keyof keyof keyof Object;
+    type T04 = keyof keyof keyof keyof Object;
+    type T05 = keyof keyof keyof keyof keyof Object;
+    type T06 = keyof keyof keyof keyof keyof keyof Object;
+    
+    type T10 = Shape["name"];
+    type T11 = Shape["foo"];  // Error
+                     ~~~~~
+!!! error TS2339: Property 'foo' does not exist on type 'Shape'.
+    type T12 = Shape["name" | "foo"];  // Error
+                     ~~~~~~~~~~~~~~
+!!! error TS2339: Property 'foo' does not exist on type 'Shape'.
+    type T13 = Shape[any];  // Error
+                     ~~~
+!!! error TS2538: Type 'any' cannot be used as an index type.
+    type T14 = Shape[string];  // Error
+                     ~~~~~~
+!!! error TS2537: Type 'Shape' has no matching index signature for type 'string'.
+    type T15 = Shape[number];  // Error
+                     ~~~~~~
+!!! error TS2537: Type 'Shape' has no matching index signature for type 'number'.
+    type T16 = Shape[boolean];  // Error
+                     ~~~~~~~
+!!! error TS2538: Type 'boolean' cannot be used as an index type.
+    type T17 = Shape[void];  // Error
+                     ~~~~
+!!! error TS2538: Type 'void' cannot be used as an index type.
+    type T18 = Shape[undefined];  // Error
+                     ~~~~~~~~~
+!!! error TS2538: Type 'undefined' cannot be used as an index type.
+    type T19 = Shape[{ x: string }];  // Error
+                     ~~~~~~~~~~~~~
+!!! error TS2538: Type '{ x: string; }' cannot be used as an index type.
+    type T20 = Shape[string | number];  // Error
+                     ~~~~~~~~~~~~~~~
+!!! error TS2537: Type 'Shape' has no matching index signature for type 'string'.
+    type T21 = Shape[string & number];  // Error
+                     ~~~~~~~~~~~~~~~
+!!! error TS2538: Type 'string & number' cannot be used as an index type.
+    type T22 = Shape[string | boolean];  // Error
+                     ~~~~~~~~~~~~~~~~
+!!! error TS2537: Type 'Shape' has no matching index signature for type 'string'.
+    
+    type T30 = string[]["length"];
+    type T31 = string[][number];
+    type T32 = string[][string];  // Error
+                        ~~~~~~
+!!! error TS2537: Type 'string[]' has no matching index signature for type 'string'.
+    type T33 = string[][boolean];  // Error
+                        ~~~~~~~
+!!! error TS2538: Type 'boolean' cannot be used as an index type.
+    
+    type T40 = Dictionary<string>[any];
+    type T41 = Dictionary<string>[number];
+    type T42 = Dictionary<string>[string];
+    type T43 = Dictionary<string>[boolean];  // Error
+                                  ~~~~~~~
+!!! error TS2538: Type 'boolean' cannot be used as an index type.
+    
+    type T50 = any[any];
+    type T51 = any[number];
+    type T52 = any[string];
+    type T53 = any[boolean];  // Error
+                   ~~~~~~~
+!!! error TS2538: Type 'boolean' cannot be used as an index type.
+    
+    type T60 = {}["toString"];
+    type T61 = []["toString"];
+    
+    declare let cond: boolean;
+    
+    function getProperty<T, K extends keyof T>(obj: T, key: K) {
+        return obj[key];
+    }
+    
+    function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+        obj[key] = value;
+    }
+    
+    function f10(shape: Shape) {
+        let x1 = getProperty(shape, "name");
+        let x2 = getProperty(shape, "size");  // Error
+                                    ~~~~~~
+!!! error TS2345: Argument of type '"size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+        let x3 = getProperty(shape, cond ? "name" : "size");  // Error
+                                    ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '"name" | "size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+!!! error TS2345:   Type '"size"' is not assignable to type '"name" | "width" | "height" | "visible"'.
+        setProperty(shape, "name", "rectangle");
+        setProperty(shape, "size", 10);  // Error
+                           ~~~~~~
+!!! error TS2345: Argument of type '"size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+        setProperty(shape, cond ? "name" : "size", 10);  // Error
+                           ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '"name" | "size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+!!! error TS2345:   Type '"size"' is not assignable to type '"name" | "width" | "height" | "visible"'.
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/keyofAndIndexedAccessErrors.js b/tests/baselines/reference/keyofAndIndexedAccessErrors.js
new file mode 100644
index 0000000000000..145d8e3f14898
--- /dev/null
+++ b/tests/baselines/reference/keyofAndIndexedAccessErrors.js
@@ -0,0 +1,90 @@
+//// [keyofAndIndexedAccessErrors.ts]
+class Shape {
+    name: string;
+    width: number;
+    height: number;
+    visible: boolean;
+}
+
+type Dictionary<T> = { [x: string]: T };
+
+type T00 = keyof K0;  // Error
+
+type T01 = keyof Object;
+type T02 = keyof keyof Object;
+type T03 = keyof keyof keyof Object;
+type T04 = keyof keyof keyof keyof Object;
+type T05 = keyof keyof keyof keyof keyof Object;
+type T06 = keyof keyof keyof keyof keyof keyof Object;
+
+type T10 = Shape["name"];
+type T11 = Shape["foo"];  // Error
+type T12 = Shape["name" | "foo"];  // Error
+type T13 = Shape[any];  // Error
+type T14 = Shape[string];  // Error
+type T15 = Shape[number];  // Error
+type T16 = Shape[boolean];  // Error
+type T17 = Shape[void];  // Error
+type T18 = Shape[undefined];  // Error
+type T19 = Shape[{ x: string }];  // Error
+type T20 = Shape[string | number];  // Error
+type T21 = Shape[string & number];  // Error
+type T22 = Shape[string | boolean];  // Error
+
+type T30 = string[]["length"];
+type T31 = string[][number];
+type T32 = string[][string];  // Error
+type T33 = string[][boolean];  // Error
+
+type T40 = Dictionary<string>[any];
+type T41 = Dictionary<string>[number];
+type T42 = Dictionary<string>[string];
+type T43 = Dictionary<string>[boolean];  // Error
+
+type T50 = any[any];
+type T51 = any[number];
+type T52 = any[string];
+type T53 = any[boolean];  // Error
+
+type T60 = {}["toString"];
+type T61 = []["toString"];
+
+declare let cond: boolean;
+
+function getProperty<T, K extends keyof T>(obj: T, key: K) {
+    return obj[key];
+}
+
+function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+    obj[key] = value;
+}
+
+function f10(shape: Shape) {
+    let x1 = getProperty(shape, "name");
+    let x2 = getProperty(shape, "size");  // Error
+    let x3 = getProperty(shape, cond ? "name" : "size");  // Error
+    setProperty(shape, "name", "rectangle");
+    setProperty(shape, "size", 10);  // Error
+    setProperty(shape, cond ? "name" : "size", 10);  // Error
+}
+
+//// [keyofAndIndexedAccessErrors.js]
+var Shape = (function () {
+    function Shape() {
+    }
+    return Shape;
+}());
+function getProperty(obj, key) {
+    return obj[key];
+}
+function setProperty(obj, key, value) {
+    obj[key] = value;
+}
+function f10(shape) {
+    var x1 = getProperty(shape, "name");
+    var x2 = getProperty(shape, "size"); // Error
+    var x3 = getProperty(shape, cond ? "name" : "size"); // Error
+    setProperty(shape, "name", "rectangle");
+    setProperty(shape, "size", 10); // Error
+    setProperty(shape, cond ? "name" : "size", 10); // Error
+}
diff --git a/tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts b/tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts
new file mode 100644
index 0000000000000..b63386a68a31e
--- /dev/null
+++ b/tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts
@@ -0,0 +1,167 @@
+// @declaration: true
+
+class Shape {
+    name: string;
+    width: number;
+    height: number;
+    visible: boolean;
+}
+
+class Item {
+    name: string;
+    price: number;
+}
+
+class Options {
+    visible: "yes" | "no";
+}
+
+type Dictionary<T> = { [x: string]: T };
+
+const enum E { A, B, C }
+
+type K00 = keyof any;  // string | number
+type K01 = keyof string;  // number | "toString" | "charAt" | ...
+type K02 = keyof number;  // "toString" | "toFixed" | "toExponential" | ...
+type K03 = keyof boolean;  // "valueOf"
+type K04 = keyof void;  // never
+type K05 = keyof undefined;  // never
+type K06 = keyof null;  // never
+type K07 = keyof never;  // never
+
+type K10 = keyof Shape;  // "name" | "width" | "height" | "visible"
+type K11 = keyof Shape[];  // number | "length" | "toString" | ...
+type K12 = keyof Dictionary<Shape>;  // string | number
+type K13 = keyof {};  // never
+type K14 = keyof Object;  // "constructor" | "toString" | ...
+type K15 = keyof E;  // "toString" | "toFixed" | "toExponential" | ...
+type K16 = keyof [string, number];  // number | "0" | "1" | "length" | "toString" | ...
+type K17 = keyof (Shape | Item);  // "name"
+type K18 = keyof (Shape & Item);  // "name" | "width" | "height" | "visible" | "price"
+
+type KeyOf<T> = keyof T;
+
+type K20 = KeyOf<Shape>;  // "name" | "width" | "height" | "visible"
+type K21 = KeyOf<Dictionary<Shape>>;  // string | number
+
+type NAME = "name";
+type WIDTH_OR_HEIGHT = "width" | "height";
+
+type Q10 = Shape["name"];  // string
+type Q11 = Shape["width" | "height"];  // number
+type Q12 = Shape["name" | "visible"];  // string | boolean
+
+type Q20 = Shape[NAME];  // string
+type Q21 = Shape[WIDTH_OR_HEIGHT];  // number
+
+type Q30 = [string, number][0];  // string
+type Q31 = [string, number][1];  // number
+type Q32 = [string, number][2];  // string | number
+type Q33 = [string, number][E.A];  // string
+type Q34 = [string, number][E.B];  // number
+type Q35 = [string, number][E.C];  // string | number
+type Q36 = [string, number]["0"];  // string
+type Q37 = [string, number]["1"];  // string
+
+type Q40 = (Shape | Options)["visible"];  // boolean | "yes" | "no"
+type Q41 = (Shape & Options)["visible"];  // true & "yes" | true & "no" | false & "yes" | false & "no"
+
+type Q50 = Dictionary<Shape>["howdy"];  // Shape
+type Q51 = Dictionary<Shape>[123];  // Shape
+type Q52 = Dictionary<Shape>[E.B];  // Shape
+
+declare let cond: boolean;
+
+function getProperty<T, K extends keyof T>(obj: T, key: K) {
+    return obj[key];
+}
+
+function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+    obj[key] = value;
+}
+
+function f10(shape: Shape) {
+    let name = getProperty(shape, "name");  // string
+    let widthOrHeight = getProperty(shape, cond ? "width" : "height");  // number
+    let nameOrVisible = getProperty(shape, cond ? "name" : "visible");  // string | boolean
+    setProperty(shape, "name", "rectangle");
+    setProperty(shape, cond ? "width" : "height", 10);
+    setProperty(shape, cond ? "name" : "visible", true);  // Technically not safe
+}
+
+function f11(a: Shape[]) {
+    let len = getProperty(a, "length");  // number
+    let shape = getProperty(a, 1000);    // Shape
+    setProperty(a, 1000, getProperty(a, 1001));
+}
+
+function f12(t: [Shape, boolean]) {
+    let len = getProperty(t, "length");
+    let s1 = getProperty(t, 0);    // Shape
+    let s2 = getProperty(t, "0");  // Shape
+    let b1 = getProperty(t, 1);    // boolean
+    let b2 = getProperty(t, "1");  // boolean
+    let x1 = getProperty(t, 2);    // Shape | boolean
+}
+
+function f13(foo: any, bar: any) {
+    let x = getProperty(foo, "x");  // any
+    let y = getProperty(foo, 100);  // any
+    let z = getProperty(foo, bar);  // any
+}
+
+class Component<PropType> {
+    props: PropType;
+    getProperty<K extends keyof PropType>(key: K) {
+        return this.props[key];
+    }
+    setProperty<K extends keyof PropType>(key: K, value: PropType[K]) {
+        this.props[key] = value;
+    }
+}
+
+function f20(component: Component<Shape>) {
+    let name = component.getProperty("name");  // string
+    let widthOrHeight = component.getProperty(cond ? "width" : "height");  // number
+    let nameOrVisible = component.getProperty(cond ? "name" : "visible");  // string | boolean
+    component.setProperty("name", "rectangle");
+    component.setProperty(cond ? "width" : "height", 10)
+    component.setProperty(cond ? "name" : "visible", true);  // Technically not safe
+}
+
+function pluck<T, K extends keyof T>(array: T[], key: K) {
+    return array.map(x => x[key]);
+}
+
+function f30(shapes: Shape[]) {
+    let names = pluck(shapes, "name");    // string[]
+    let widths = pluck(shapes, "width");  // number[]
+    let nameOrVisibles = pluck(shapes, cond ? "name" : "visible");  // (string | boolean)[]
+}
+
+function f31<K extends keyof Shape>(key: K) {
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+    return shape[key];  // Shape[K]
+}
+
+function f32<K extends "width" | "height">(key: K) {
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+    return shape[key];  // Shape[K]
+}
+
+class C {
+    public x: string;
+    protected y: string;
+    private z: string;
+}
+
+// Indexed access expressions have always permitted access to private and protected members.
+// For consistency we also permit such access in indexed access types.
+function f40(c: C) {
+    type X = C["x"];
+    type Y = C["y"];
+    type Z = C["z"];
+    let x: X = c["x"];
+    let y: Y = c["y"];
+    let z: Z = c["z"];
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts b/tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts
new file mode 100644
index 0000000000000..bc2ddc31a1920
--- /dev/null
+++ b/tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts
@@ -0,0 +1,68 @@
+class Shape {
+    name: string;
+    width: number;
+    height: number;
+    visible: boolean;
+}
+
+type Dictionary<T> = { [x: string]: T };
+
+type T00 = keyof K0;  // Error
+
+type T01 = keyof Object;
+type T02 = keyof keyof Object;
+type T03 = keyof keyof keyof Object;
+type T04 = keyof keyof keyof keyof Object;
+type T05 = keyof keyof keyof keyof keyof Object;
+type T06 = keyof keyof keyof keyof keyof keyof Object;
+
+type T10 = Shape["name"];
+type T11 = Shape["foo"];  // Error
+type T12 = Shape["name" | "foo"];  // Error
+type T13 = Shape[any];  // Error
+type T14 = Shape[string];  // Error
+type T15 = Shape[number];  // Error
+type T16 = Shape[boolean];  // Error
+type T17 = Shape[void];  // Error
+type T18 = Shape[undefined];  // Error
+type T19 = Shape[{ x: string }];  // Error
+type T20 = Shape[string | number];  // Error
+type T21 = Shape[string & number];  // Error
+type T22 = Shape[string | boolean];  // Error
+
+type T30 = string[]["length"];
+type T31 = string[][number];
+type T32 = string[][string];  // Error
+type T33 = string[][boolean];  // Error
+
+type T40 = Dictionary<string>[any];
+type T41 = Dictionary<string>[number];
+type T42 = Dictionary<string>[string];
+type T43 = Dictionary<string>[boolean];  // Error
+
+type T50 = any[any];
+type T51 = any[number];
+type T52 = any[string];
+type T53 = any[boolean];  // Error
+
+type T60 = {}["toString"];
+type T61 = []["toString"];
+
+declare let cond: boolean;
+
+function getProperty<T, K extends keyof T>(obj: T, key: K) {
+    return obj[key];
+}
+
+function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+    obj[key] = value;
+}
+
+function f10(shape: Shape) {
+    let x1 = getProperty(shape, "name");
+    let x2 = getProperty(shape, "size");  // Error
+    let x3 = getProperty(shape, cond ? "name" : "size");  // Error
+    setProperty(shape, "name", "rectangle");
+    setProperty(shape, "size", 10);  // Error
+    setProperty(shape, cond ? "name" : "size", 10);  // Error
+}
\ No newline at end of file

From 116c87819a737c9c31d97989d1982444e2885727 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Wed, 2 Nov 2016 11:07:33 -0700
Subject: [PATCH 147/224] Test case for property used in destructuring variable
 declaration

---
 .../reference/unusedLocalProperty.errors.txt  | 18 +++++++++++++
 .../reference/unusedLocalProperty.js          | 25 +++++++++++++++++++
 tests/cases/compiler/unusedLocalProperty.ts   | 12 +++++++++
 3 files changed, 55 insertions(+)
 create mode 100644 tests/baselines/reference/unusedLocalProperty.errors.txt
 create mode 100644 tests/baselines/reference/unusedLocalProperty.js
 create mode 100644 tests/cases/compiler/unusedLocalProperty.ts

diff --git a/tests/baselines/reference/unusedLocalProperty.errors.txt b/tests/baselines/reference/unusedLocalProperty.errors.txt
new file mode 100644
index 0000000000000..c9a4b3cb6d9ad
--- /dev/null
+++ b/tests/baselines/reference/unusedLocalProperty.errors.txt
@@ -0,0 +1,18 @@
+tests/cases/compiler/unusedLocalProperty.ts(3,25): error TS6138: Property 'species' is declared but never used.
+
+
+==== tests/cases/compiler/unusedLocalProperty.ts (1 errors) ====
+    declare var console: { log(msg: any): void; }
+    class Animal {
+        constructor(private species: string) {
+                            ~~~~~~~
+!!! error TS6138: Property 'species' is declared but never used.
+        }
+    
+        printSpecies() {
+            let { species } = this;
+            console.log(species);
+        }
+    }
+    
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/unusedLocalProperty.js b/tests/baselines/reference/unusedLocalProperty.js
new file mode 100644
index 0000000000000..a124b752125d7
--- /dev/null
+++ b/tests/baselines/reference/unusedLocalProperty.js
@@ -0,0 +1,25 @@
+//// [unusedLocalProperty.ts]
+declare var console: { log(msg: any): void; }
+class Animal {
+    constructor(private species: string) {
+    }
+
+    printSpecies() {
+        let { species } = this;
+        console.log(species);
+    }
+}
+
+
+
+//// [unusedLocalProperty.js]
+var Animal = (function () {
+    function Animal(species) {
+        this.species = species;
+    }
+    Animal.prototype.printSpecies = function () {
+        var species = this.species;
+        console.log(species);
+    };
+    return Animal;
+}());
diff --git a/tests/cases/compiler/unusedLocalProperty.ts b/tests/cases/compiler/unusedLocalProperty.ts
new file mode 100644
index 0000000000000..fdd33116135fc
--- /dev/null
+++ b/tests/cases/compiler/unusedLocalProperty.ts
@@ -0,0 +1,12 @@
+//@noUnusedLocals:true
+declare var console: { log(msg: any): void; }
+class Animal {
+    constructor(private species: string) {
+    }
+
+    printSpecies() {
+        let { species } = this;
+        console.log(species);
+    }
+}
+

From 13e8f7fadaa702bc871e98edc592c11a3d2c439a Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Wed, 2 Nov 2016 11:08:34 -0700
Subject: [PATCH 148/224] Mark property referenced in the destructuring as
 referenced Fixes #11324

---
 src/compiler/checker.ts                       | 28 ++++++++++-------
 .../reference/unusedLocalProperty.errors.txt  | 18 -----------
 .../reference/unusedLocalProperty.symbols     | 29 ++++++++++++++++++
 .../reference/unusedLocalProperty.types       | 30 +++++++++++++++++++
 4 files changed, 76 insertions(+), 29 deletions(-)
 delete mode 100644 tests/baselines/reference/unusedLocalProperty.errors.txt
 create mode 100644 tests/baselines/reference/unusedLocalProperty.symbols
 create mode 100644 tests/baselines/reference/unusedLocalProperty.types

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index cf0c048ecbfb8..cfba499921299 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -11504,6 +11504,21 @@ namespace ts {
             diagnostics.add(createDiagnosticForNodeFromMessageChain(propNode, errorInfo));
         }
 
+        function markPropertyAsReferenced(prop: Symbol) {
+            if (prop &&
+                noUnusedIdentifiers &&
+                (prop.flags & SymbolFlags.ClassMember) &&
+                prop.valueDeclaration && (getModifierFlags(prop.valueDeclaration) & ModifierFlags.Private)) {
+                if (prop.flags & SymbolFlags.Instantiated) {
+                    getSymbolLinks(prop).target.isReferenced = true;
+
+                }
+                else {
+                    prop.isReferenced = true;
+                }
+            }
+        }
+
         function checkPropertyAccessExpressionOrQualifiedName(node: PropertyAccessExpression | QualifiedName, left: Expression | QualifiedName, right: Identifier) {
             const type = checkNonNullExpression(left);
             if (isTypeAny(type) || type === silentNeverType) {
@@ -11523,17 +11538,7 @@ namespace ts {
                 return unknownType;
             }
 
-            if (noUnusedIdentifiers &&
-                (prop.flags & SymbolFlags.ClassMember) &&
-                prop.valueDeclaration && (getModifierFlags(prop.valueDeclaration) & ModifierFlags.Private)) {
-                if (prop.flags & SymbolFlags.Instantiated) {
-                    getSymbolLinks(prop).target.isReferenced = true;
-
-                }
-                else {
-                    prop.isReferenced = true;
-                }
-            }
+            markPropertyAsReferenced(prop);
 
             getNodeLinks(node).resolvedSymbol = prop;
 
@@ -16323,6 +16328,7 @@ namespace ts {
                 const parentType = getTypeForBindingElementParent(parent);
                 const name = node.propertyName || <Identifier>node.name;
                 const property = getPropertyOfType(parentType, getTextOfPropertyName(name));
+                markPropertyAsReferenced(property);
                 if (parent.initializer && property && getParentOfSymbol(property)) {
                     checkClassPropertyAccess(parent, parent.initializer, parentType, property);
                 }
diff --git a/tests/baselines/reference/unusedLocalProperty.errors.txt b/tests/baselines/reference/unusedLocalProperty.errors.txt
deleted file mode 100644
index c9a4b3cb6d9ad..0000000000000
--- a/tests/baselines/reference/unusedLocalProperty.errors.txt
+++ /dev/null
@@ -1,18 +0,0 @@
-tests/cases/compiler/unusedLocalProperty.ts(3,25): error TS6138: Property 'species' is declared but never used.
-
-
-==== tests/cases/compiler/unusedLocalProperty.ts (1 errors) ====
-    declare var console: { log(msg: any): void; }
-    class Animal {
-        constructor(private species: string) {
-                            ~~~~~~~
-!!! error TS6138: Property 'species' is declared but never used.
-        }
-    
-        printSpecies() {
-            let { species } = this;
-            console.log(species);
-        }
-    }
-    
-    
\ No newline at end of file
diff --git a/tests/baselines/reference/unusedLocalProperty.symbols b/tests/baselines/reference/unusedLocalProperty.symbols
new file mode 100644
index 0000000000000..6a3343bd5456e
--- /dev/null
+++ b/tests/baselines/reference/unusedLocalProperty.symbols
@@ -0,0 +1,29 @@
+=== tests/cases/compiler/unusedLocalProperty.ts ===
+declare var console: { log(msg: any): void; }
+>console : Symbol(console, Decl(unusedLocalProperty.ts, 0, 11))
+>log : Symbol(log, Decl(unusedLocalProperty.ts, 0, 22))
+>msg : Symbol(msg, Decl(unusedLocalProperty.ts, 0, 27))
+
+class Animal {
+>Animal : Symbol(Animal, Decl(unusedLocalProperty.ts, 0, 45))
+
+    constructor(private species: string) {
+>species : Symbol(Animal.species, Decl(unusedLocalProperty.ts, 2, 16))
+    }
+
+    printSpecies() {
+>printSpecies : Symbol(Animal.printSpecies, Decl(unusedLocalProperty.ts, 3, 5))
+
+        let { species } = this;
+>species : Symbol(species, Decl(unusedLocalProperty.ts, 6, 13))
+>this : Symbol(Animal, Decl(unusedLocalProperty.ts, 0, 45))
+
+        console.log(species);
+>console.log : Symbol(log, Decl(unusedLocalProperty.ts, 0, 22))
+>console : Symbol(console, Decl(unusedLocalProperty.ts, 0, 11))
+>log : Symbol(log, Decl(unusedLocalProperty.ts, 0, 22))
+>species : Symbol(species, Decl(unusedLocalProperty.ts, 6, 13))
+    }
+}
+
+
diff --git a/tests/baselines/reference/unusedLocalProperty.types b/tests/baselines/reference/unusedLocalProperty.types
new file mode 100644
index 0000000000000..3cb8747957db5
--- /dev/null
+++ b/tests/baselines/reference/unusedLocalProperty.types
@@ -0,0 +1,30 @@
+=== tests/cases/compiler/unusedLocalProperty.ts ===
+declare var console: { log(msg: any): void; }
+>console : { log(msg: any): void; }
+>log : (msg: any) => void
+>msg : any
+
+class Animal {
+>Animal : Animal
+
+    constructor(private species: string) {
+>species : string
+    }
+
+    printSpecies() {
+>printSpecies : () => void
+
+        let { species } = this;
+>species : string
+>this : this
+
+        console.log(species);
+>console.log(species) : void
+>console.log : (msg: any) => void
+>console : { log(msg: any): void; }
+>log : (msg: any) => void
+>species : string
+    }
+}
+
+

From f2d739ffcfef63b738bf6d71eb9e9d8b552cb71b Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 2 Nov 2016 11:36:25 -0700
Subject: [PATCH 149/224] Spread types handle nested index [access] types

Nested index [access] types are treated as assignable to themselves only,
just like type parameters.
---
 src/compiler/checker.ts | 7 ++++---
 src/compiler/types.ts   | 2 +-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 53d38c1892ff8..5447e652f08fe 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -6097,10 +6097,10 @@ namespace ts {
             }
             const spread = spreadTypes[id] = createType(TypeFlags.Spread) as SpreadType;
             Debug.assert(!!(left.flags & (TypeFlags.Spread | TypeFlags.Object)), "Left flags: " + left.flags.toString(2));
-            Debug.assert(!!(right.flags & (TypeFlags.TypeParameter | TypeFlags.Intersection | TypeFlags.Object)), "Right flags: " + right.flags.toString(2));
+            Debug.assert(!!(right.flags & (TypeFlags.TypeParameter | TypeFlags.Intersection | TypeFlags.Index | TypeFlags.IndexedAccess | TypeFlags.Object)), "Right flags: " + right.flags.toString(2));
             spread.symbol = symbol;
             spread.left = left as SpreadType | ResolvedType;
-            spread.right = right as TypeParameter | IntersectionType | ResolvedType;
+            spread.right = right as TypeParameter | IntersectionType | IndexType | IndexedAccessType | ResolvedType;
             spread.aliasSymbol = aliasSymbol;
             spread.aliasTypeArguments = aliasTypeArguments;
             return spread;
@@ -7173,7 +7173,8 @@ namespace ts {
                         spreadTypeRelatedTo(source.right.flags & TypeFlags.Object ? source.left as SpreadType : source,
                                             target.right.flags & TypeFlags.Object ? target.left as SpreadType : target);
                 }
-                // If both right sides are type parameters or intersections, then they must be identical for the spread types to be related.
+                // If both right sides are type parameters, intersections, index types or indexed access types,
+                // then they must be identical for the spread types to be related.
                 // It also means that the left sides are either spread types or object types.
 
                 // if one left is object and the other is spread, that means the second has another type parameter. which isn't allowed
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 73d1c6d1ed9e7..ba5e6b2db9971 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2852,7 +2852,7 @@ namespace ts {
     /* @internal */
     export interface SpreadType extends Type {
         left: SpreadType | ResolvedType;
-        right: TypeParameter | IntersectionType | ResolvedType;
+        right: TypeParameter | IntersectionType | IndexType | IndexedAccessType | ResolvedType;
     }
 
     /* @internal */

From f65dd2101c33fc6e222e97757c892402c68fe99a Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 2 Nov 2016 11:37:52 -0700
Subject: [PATCH 150/224] Test index [access] types inside spread types

---
 .../reference/objectSpreadGeneric.errors.txt  | 50 ++++++++++++++++++-
 .../reference/objectSpreadGeneric.js          | 46 +++++++++++++++++
 .../types/spread/objectSpreadGeneric.ts       | 24 +++++++++
 3 files changed, 119 insertions(+), 1 deletion(-)

diff --git a/tests/baselines/reference/objectSpreadGeneric.errors.txt b/tests/baselines/reference/objectSpreadGeneric.errors.txt
index 8b9c767f6de3d..f1e2b7e4828f5 100644
--- a/tests/baselines/reference/objectSpreadGeneric.errors.txt
+++ b/tests/baselines/reference/objectSpreadGeneric.errors.txt
@@ -14,9 +14,17 @@ tests/cases/conformance/types/spread/objectSpreadGeneric.ts(38,11): error TS2322
 tests/cases/conformance/types/spread/objectSpreadGeneric.ts(42,11): error TS2322: Type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
 tests/cases/conformance/types/spread/objectSpreadGeneric.ts(44,11): error TS2322: Type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
 tests/cases/conformance/types/spread/objectSpreadGeneric.ts(46,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(57,5): error TS2322: Type '{ ...keyof U }' is not assignable to type '{ ...keyof T }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(58,5): error TS2322: Type '{ ...keyof T }' is not assignable to type '{ ...keyof U }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(61,5): error TS2322: Type '{ ...K }' is not assignable to type '{ ...keyof T }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(62,5): error TS2322: Type '{ ...keyof T }' is not assignable to type '{ ...K }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(63,5): error TS2322: Type '{ ...J }' is not assignable to type '{ ...keyof U }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(64,5): error TS2322: Type '{ ...keyof U }' is not assignable to type '{ ...J }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(70,5): error TS2322: Type '{ ...U[J] }' is not assignable to type '{ ...T[K] }'.
+tests/cases/conformance/types/spread/objectSpreadGeneric.ts(71,5): error TS2322: Type '{ ...T[K] }' is not assignable to type '{ ...U[J] }'.
 
 
-==== tests/cases/conformance/types/spread/objectSpreadGeneric.ts (16 errors) ====
+==== tests/cases/conformance/types/spread/objectSpreadGeneric.ts (24 errors) ====
     function f<T, U, V>(t: T, u: U, v: V): void {
         let o: { ...T, ...U, ...V };
         let uus: { ...U, ...U};
@@ -97,4 +105,44 @@ tests/cases/conformance/types/spread/objectSpreadGeneric.ts(46,11): error TS2322
 !!! error TS2322: Type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
             { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, not assignable
     }
+    
+    function indexAccessedTest<T, K extends keyof T, U, J extends keyof U>(t: T, u: U, key1: K, key2: J) {
+        let k1: { ...keyof T };
+        let k2: { ...keyof U };
+        let k3: { ...K };
+        let k4: { ...J };
+        k1 = k1; // ok
+        k2 = k2; // ok
+        k1 = k2; // error
+        ~~
+!!! error TS2322: Type '{ ...keyof U }' is not assignable to type '{ ...keyof T }'.
+        k2 = k1; // error
+        ~~
+!!! error TS2322: Type '{ ...keyof T }' is not assignable to type '{ ...keyof U }'.
+        k3 = k3; // ok
+        k4 = k4; // ok
+        k1 = k3; // error
+        ~~
+!!! error TS2322: Type '{ ...K }' is not assignable to type '{ ...keyof T }'.
+        k3 = k1; // error
+        ~~
+!!! error TS2322: Type '{ ...keyof T }' is not assignable to type '{ ...K }'.
+        k2 = k4; // error
+        ~~
+!!! error TS2322: Type '{ ...J }' is not assignable to type '{ ...keyof U }'.
+        k4 = k2; // error
+        ~~
+!!! error TS2322: Type '{ ...keyof U }' is not assignable to type '{ ...J }'.
+    
+        let i1: { ...T[K] };
+        let i2: { ...U[J] };
+        i1 = i1; // ok
+        i2 = i2; // ok
+        i1 = i2; // error
+        ~~
+!!! error TS2322: Type '{ ...U[J] }' is not assignable to type '{ ...T[K] }'.
+        i2 = i1; // error
+        ~~
+!!! error TS2322: Type '{ ...T[K] }' is not assignable to type '{ ...U[J] }'.
+    }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadGeneric.js b/tests/baselines/reference/objectSpreadGeneric.js
index fa19e47df39e7..8e89ebeef6416 100644
--- a/tests/baselines/reference/objectSpreadGeneric.js
+++ b/tests/baselines/reference/objectSpreadGeneric.js
@@ -47,6 +47,30 @@ function f<T, U, V>(t: T, u: U, v: V): void {
     const mismatchLast: { first: string, ...T, second: string, ...U, third: string } =
         { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, not assignable
 }
+
+function indexAccessedTest<T, K extends keyof T, U, J extends keyof U>(t: T, u: U, key1: K, key2: J) {
+    let k1: { ...keyof T };
+    let k2: { ...keyof U };
+    let k3: { ...K };
+    let k4: { ...J };
+    k1 = k1; // ok
+    k2 = k2; // ok
+    k1 = k2; // error
+    k2 = k1; // error
+    k3 = k3; // ok
+    k4 = k4; // ok
+    k1 = k3; // error
+    k3 = k1; // error
+    k2 = k4; // error
+    k4 = k2; // error
+
+    let i1: { ...T[K] };
+    let i2: { ...U[J] };
+    i1 = i1; // ok
+    i2 = i2; // ok
+    i1 = i2; // error
+    i2 = i1; // error
+}
 
 
 //// [objectSpreadGeneric.js]
@@ -93,3 +117,25 @@ function f(t, u, v) {
     var mismatchSecond = __assign({ first: '1' }, t, { ssssssssecond: '2' }, u, { third: '3' }); // error, not assignable
     var mismatchLast = __assign({ first: '1' }, t, { second: '2' }, u, { thirrrrrrrd: '3' }); // error, not assignable
 }
+function indexAccessedTest(t, u, key1, key2) {
+    var k1;
+    var k2;
+    var k3;
+    var k4;
+    k1 = k1; // ok
+    k2 = k2; // ok
+    k1 = k2; // error
+    k2 = k1; // error
+    k3 = k3; // ok
+    k4 = k4; // ok
+    k1 = k3; // error
+    k3 = k1; // error
+    k2 = k4; // error
+    k4 = k2; // error
+    var i1;
+    var i2;
+    i1 = i1; // ok
+    i2 = i2; // ok
+    i1 = i2; // error
+    i2 = i1; // error
+}
diff --git a/tests/cases/conformance/types/spread/objectSpreadGeneric.ts b/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
index 63e9f00aaae62..6f22358b7e25a 100644
--- a/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
@@ -46,3 +46,27 @@ function f<T, U, V>(t: T, u: U, v: V): void {
     const mismatchLast: { first: string, ...T, second: string, ...U, third: string } =
         { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, not assignable
 }
+
+function indexAccessedTest<T, K extends keyof T, U, J extends keyof U>(t: T, u: U, key1: K, key2: J) {
+    let k1: { ...keyof T };
+    let k2: { ...keyof U };
+    let k3: { ...K };
+    let k4: { ...J };
+    k1 = k1; // ok
+    k2 = k2; // ok
+    k1 = k2; // error
+    k2 = k1; // error
+    k3 = k3; // ok
+    k4 = k4; // ok
+    k1 = k3; // error
+    k3 = k1; // error
+    k2 = k4; // error
+    k4 = k2; // error
+
+    let i1: { ...T[K] };
+    let i2: { ...U[J] };
+    i1 = i1; // ok
+    i2 = i2; // ok
+    i1 = i2; // error
+    i2 = i1; // error
+}

From ab75ea75d337d82138083c52caea7419f3b20929 Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Wed, 2 Nov 2016 14:41:26 -0700
Subject: [PATCH 151/224] module resolution: prefer locally defined ambient
 modules, reuse resolutions to ambient modules from the old program (#11999)

module resolution: prefer locally defined ambient modules, reuse resolutions to ambient modules from the old program
---
 src/compiler/checker.ts                       |  29 ++-
 src/compiler/diagnosticMessages.json          |   8 +
 src/compiler/moduleNameResolver.ts            |   9 +-
 src/compiler/program.ts                       | 189 +++++++++++++++---
 src/compiler/types.ts                         |   3 +
 src/harness/unittests/moduleResolution.ts     |  64 ++++++
 .../unittests/reuseProgramStructure.ts        | 136 ++++++++++++-
 src/services/services.ts                      |   1 +
 8 files changed, 394 insertions(+), 45 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index cf0c048ecbfb8..006b87cb542ee 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -107,7 +107,12 @@ namespace ts {
 
             getJsxElementAttributesType,
             getJsxIntrinsicTagNames,
-            isOptionalParameter
+            isOptionalParameter,
+            tryFindAmbientModuleWithoutAugmentations: moduleName => {
+                // we deliberately exclude augmentations
+                // since we are only interested in declarations of the module itself
+                return tryFindAmbientModule(moduleName, /*withAugmentations*/ false);
+            }
         };
 
         const tupleTypes: GenericType[] = [];
@@ -1370,16 +1375,11 @@ namespace ts {
                 return;
             }
 
-            const isRelative = isExternalModuleNameRelative(moduleName);
-            const quotedName = '"' + moduleName + '"';
-            if (!isRelative) {
-                const symbol = getSymbol(globals, quotedName, SymbolFlags.ValueModule);
-                if (symbol) {
-                    // merged symbol is module declaration symbol combined with all augmentations
-                    return getMergedSymbol(symbol);
-                }
+            const ambientModule = tryFindAmbientModule(moduleName, /*withAugmentations*/ true);
+            if (ambientModule) {
+                return ambientModule;
             }
-
+            const isRelative = isExternalModuleNameRelative(moduleName);
             const resolvedModule = getResolvedModule(getSourceFileOfNode(location), moduleReference);
             const resolutionDiagnostic = resolvedModule && getResolutionDiagnostic(compilerOptions, resolvedModule);
             const sourceFile = resolvedModule && !resolutionDiagnostic && host.getSourceFile(resolvedModule.resolvedFileName);
@@ -4734,6 +4734,15 @@ namespace ts {
             }
         }
 
+        function tryFindAmbientModule(moduleName: string, withAugmentations: boolean) {
+            if (isExternalModuleNameRelative(moduleName)) {
+                return undefined;
+            }
+            const symbol = getSymbol(globals, `"${moduleName}"`, SymbolFlags.ValueModule);
+            // merged symbol is module declaration symbol combined with all augmentations
+            return symbol && withAugmentations ? getMergedSymbol(symbol) : symbol;
+        }
+
         function isOptionalParameter(node: ParameterDeclaration) {
             if (hasQuestionToken(node) || isJSDocOptionalParameter(node)) {
                 return true;
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 7f88d5fed72bc..5290782c156a2 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -2889,6 +2889,14 @@
         "category": "Error",
         "code": 6143
     },
+    "Module '{0}' was resolved as locally declared ambient module in file '{1}'.": {
+        "category": "Message",
+        "code": 6144
+    },
+    "Module '{0}' was resolved as ambient module declared in '{1}' since this file was not modified.": {
+        "category": "Message",
+        "code": 6145
+    },
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005
diff --git a/src/compiler/moduleNameResolver.ts b/src/compiler/moduleNameResolver.ts
index 9e159a356c7c7..86e0157d84729 100644
--- a/src/compiler/moduleNameResolver.ts
+++ b/src/compiler/moduleNameResolver.ts
@@ -2,12 +2,15 @@
 /// <reference path="diagnosticInformationMap.generated.ts" />
 
 namespace ts {
-    function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void;
-    function trace(host: ModuleResolutionHost): void {
+
+    /* @internal */
+    export function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void;
+    export function trace(host: ModuleResolutionHost): void {
         host.trace(formatMessage.apply(undefined, arguments));
     }
 
-    function isTraceEnabled(compilerOptions: CompilerOptions, host: ModuleResolutionHost): boolean {
+    /* @internal */
+    export function isTraceEnabled(compilerOptions: CompilerOptions, host: ModuleResolutionHost): boolean {
         return compilerOptions.traceResolution && host.trace !== undefined;
     }
 
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 726df380e81b1..82d274e0487df 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -462,6 +462,130 @@ namespace ts {
             return classifiableNames;
         }
 
+        interface OldProgramState {
+            program: Program;
+            file: SourceFile;
+            modifiedFilePaths: Path[];
+        }
+
+        function resolveModuleNamesReusingOldState(moduleNames: string[], containingFile: string, file: SourceFile, oldProgramState?: OldProgramState) {
+            if (!oldProgramState && !file.ambientModuleNames.length) {
+                // if old program state is not supplied and file does not contain locally defined ambient modules
+                // then the best we can do is fallback to the default logic
+                return resolveModuleNamesWorker(moduleNames, containingFile);
+            }
+
+            // at this point we know that either 
+            // - file has local declarations for ambient modules
+            // OR
+            // - old program state is available
+            // OR
+            // - both of items above
+            // With this it is possible that we can tell how some module names from the initial list will be resolved
+            // without doing actual resolution (in particular if some name was resolved to ambient module).
+            // Such names should be excluded from the list of module names that will be provided to `resolveModuleNamesWorker`
+            // since we don't want to resolve them again.
+
+            // this is a list of modules for which we cannot predict resolution so they should be actually resolved
+            let unknownModuleNames: string[];
+            // this is a list of combined results assembles from predicted and resolved results.
+            // Order in this list matches the order in the original list of module names `moduleNames` which is important
+            // so later we can split results to resolutions of modules and resolutions of module augmentations.
+            let result: ResolvedModuleFull[];
+            // a transient placeholder that is used to mark predicted resolution in the result list
+            const predictedToResolveToAmbientModuleMarker: ResolvedModuleFull = <any>{};
+
+            for (let i = 0; i < moduleNames.length; i++) {
+                const moduleName = moduleNames[i];
+                // module name is known to be resolved to ambient module if
+                // - module name is contained in the list of ambient modules that are locally declared in the file
+                // - in the old program module name was resolved to ambient module whose declaration is in non-modified file
+                //   (so the same module declaration will land in the new program)
+                let isKnownToResolveToAmbientModule = false;
+                if (contains(file.ambientModuleNames, moduleName)) {
+                    isKnownToResolveToAmbientModule = true;
+                    if (isTraceEnabled(options, host)) {
+                        trace(host, Diagnostics.Module_0_was_resolved_as_locally_declared_ambient_module_in_file_1, moduleName, containingFile);
+                    }
+                }
+                else {
+                    isKnownToResolveToAmbientModule = checkModuleNameResolvedToAmbientModuleInNonModifiedFile(moduleName, oldProgramState);
+                }
+
+                if (isKnownToResolveToAmbientModule) {
+                    if (!unknownModuleNames) {
+                        // found a first module name for which result can be prediced
+                        // this means that this module name should not be passed to `resolveModuleNamesWorker`.
+                        // We'll use a separate list for module names that are definitely unknown.
+                        result = new Array(moduleNames.length);
+                        // copy all module names that appear before the current one in the list
+                        // since they are known to be unknown
+                        unknownModuleNames = moduleNames.slice(0, i);
+                    }
+                    // mark prediced resolution in the result list
+                    result[i] = predictedToResolveToAmbientModuleMarker;
+                }
+                else if (unknownModuleNames) {
+                    // found unknown module name and we are already using separate list for those - add it to the list
+                    unknownModuleNames.push(moduleName);
+                }
+            }
+
+            if (!unknownModuleNames) {
+                // we've looked throught the list but have not seen any predicted resolution
+                // use default logic
+                return resolveModuleNamesWorker(moduleNames, containingFile);
+            }
+
+            const resolutions = unknownModuleNames.length
+                ? resolveModuleNamesWorker(unknownModuleNames, containingFile)
+                : emptyArray;
+
+            // combine results of resolutions and predicted results
+            let j = 0;
+            for (let i = 0; i < result.length; i++) {
+                if (result[i] == predictedToResolveToAmbientModuleMarker) {
+                    result[i] = undefined;
+                }
+                else {
+                    result[i] = resolutions[j];
+                    j++;
+                }
+            }
+            Debug.assert(j === resolutions.length);
+            return result;
+
+            function checkModuleNameResolvedToAmbientModuleInNonModifiedFile(moduleName: string, oldProgramState?: OldProgramState): boolean {
+                if (!oldProgramState) {
+                    return false;
+                }
+                const resolutionToFile = getResolvedModule(oldProgramState.file, moduleName);
+                if (resolutionToFile) {
+                    // module used to be resolved to file - ignore it
+                    return false;
+                }
+                const ambientModule = oldProgram.getTypeChecker().tryFindAmbientModuleWithoutAugmentations(moduleName);
+                if (!(ambientModule && ambientModule.declarations)) {
+                    return false;
+                }
+
+                // at least one of declarations should come from non-modified source file
+                const firstUnmodifiedFile = forEach(ambientModule.declarations, d => {
+                    const f = getSourceFileOfNode(d);
+                    return !contains(oldProgramState.modifiedFilePaths, f.path) && f;
+                });
+
+                if (!firstUnmodifiedFile) {
+                    return false;
+                }
+
+                if (isTraceEnabled(options, host)) {
+                    trace(host, Diagnostics.Module_0_was_resolved_as_ambient_module_declared_in_1_since_this_file_was_not_modified, moduleName, firstUnmodifiedFile.fileName);
+                }
+                return true;
+            }
+        }
+
         function tryReuseStructureFromOldProgram(): boolean {
             if (!oldProgram) {
                 return false;
@@ -489,7 +613,7 @@ namespace ts {
             // check if program source files has changed in the way that can affect structure of the program
             const newSourceFiles: SourceFile[] = [];
             const filePaths: Path[] = [];
-            const modifiedSourceFiles: SourceFile[] = [];
+            const modifiedSourceFiles: { oldFile: SourceFile, newFile: SourceFile }[] = [];
 
             for (const oldSourceFile of oldProgram.getSourceFiles()) {
                 let newSourceFile = host.getSourceFileByPath
@@ -532,29 +656,8 @@ namespace ts {
                         return false;
                     }
 
-                    const newSourceFilePath = getNormalizedAbsolutePath(newSourceFile.fileName, currentDirectory);
-                    if (resolveModuleNamesWorker) {
-                        const moduleNames = map(concatenate(newSourceFile.imports, newSourceFile.moduleAugmentations), getTextOfLiteral);
-                        const resolutions = resolveModuleNamesWorker(moduleNames, newSourceFilePath);
-                        // ensure that module resolution results are still correct
-                        const resolutionsChanged = hasChangesInResolutions(moduleNames, resolutions, oldSourceFile.resolvedModules, moduleResolutionIsEqualTo);
-                        if (resolutionsChanged) {
-                            return false;
-                        }
-                    }
-                    if (resolveTypeReferenceDirectiveNamesWorker) {
-                        const typesReferenceDirectives = map(newSourceFile.typeReferenceDirectives, x => x.fileName);
-                        const resolutions = resolveTypeReferenceDirectiveNamesWorker(typesReferenceDirectives, newSourceFilePath);
-                        // ensure that types resolutions are still correct
-                        const resolutionsChanged = hasChangesInResolutions(typesReferenceDirectives, resolutions, oldSourceFile.resolvedTypeReferenceDirectiveNames, typeDirectiveIsEqualTo);
-                        if (resolutionsChanged) {
-                            return false;
-                        }
-                    }
-                    // pass the cache of module/types resolutions from the old source file
-                    newSourceFile.resolvedModules = oldSourceFile.resolvedModules;
-                    newSourceFile.resolvedTypeReferenceDirectiveNames = oldSourceFile.resolvedTypeReferenceDirectiveNames;
-                    modifiedSourceFiles.push(newSourceFile);
+                    // tentatively approve the file
+                    modifiedSourceFiles.push({ oldFile: oldSourceFile, newFile: newSourceFile });
                 }
                 else {
                     // file has no changes - use it as is
@@ -565,6 +668,33 @@ namespace ts {
                 newSourceFiles.push(newSourceFile);
             }
 
+            const modifiedFilePaths = modifiedSourceFiles.map(f => f.newFile.path);
+            // try to verify results of module resolution 
+            for (const { oldFile: oldSourceFile, newFile: newSourceFile } of modifiedSourceFiles) {
+                const newSourceFilePath = getNormalizedAbsolutePath(newSourceFile.fileName, currentDirectory);
+                if (resolveModuleNamesWorker) {
+                    const moduleNames = map(concatenate(newSourceFile.imports, newSourceFile.moduleAugmentations), getTextOfLiteral);
+                    const resolutions = resolveModuleNamesReusingOldState(moduleNames, newSourceFilePath, newSourceFile, { file: oldSourceFile, program: oldProgram, modifiedFilePaths });
+                    // ensure that module resolution results are still correct
+                    const resolutionsChanged = hasChangesInResolutions(moduleNames, resolutions, oldSourceFile.resolvedModules, moduleResolutionIsEqualTo);
+                    if (resolutionsChanged) {
+                        return false;
+                    }
+                }
+                if (resolveTypeReferenceDirectiveNamesWorker) {
+                    const typesReferenceDirectives = map(newSourceFile.typeReferenceDirectives, x => x.fileName);
+                    const resolutions = resolveTypeReferenceDirectiveNamesWorker(typesReferenceDirectives, newSourceFilePath);
+                    // ensure that types resolutions are still correct
+                    const resolutionsChanged = hasChangesInResolutions(typesReferenceDirectives, resolutions, oldSourceFile.resolvedTypeReferenceDirectiveNames, typeDirectiveIsEqualTo);
+                    if (resolutionsChanged) {
+                        return false;
+                    }
+                }
+                // pass the cache of module/types resolutions from the old source file
+                newSourceFile.resolvedModules = oldSourceFile.resolvedModules;
+                newSourceFile.resolvedTypeReferenceDirectiveNames = oldSourceFile.resolvedTypeReferenceDirectiveNames;
+            }
+
             // update fileName -> file mapping
             for (let i = 0, len = newSourceFiles.length; i < len; i++) {
                 filesByName.set(filePaths[i], newSourceFiles[i]);
@@ -574,7 +704,7 @@ namespace ts {
             fileProcessingDiagnostics = oldProgram.getFileProcessingDiagnostics();
 
             for (const modifiedFile of modifiedSourceFiles) {
-                fileProcessingDiagnostics.reattachFileDiagnostics(modifiedFile);
+                fileProcessingDiagnostics.reattachFileDiagnostics(modifiedFile.newFile);
             }
             resolvedTypeReferenceDirectives = oldProgram.getResolvedTypeReferenceDirectives();
             oldProgram.structureIsReused = true;
@@ -994,9 +1124,11 @@ namespace ts {
 
             const isJavaScriptFile = isSourceFileJavaScript(file);
             const isExternalModuleFile = isExternalModule(file);
+            const isDtsFile = isDeclarationFile(file);
 
             let imports: LiteralExpression[];
             let moduleAugmentations: LiteralExpression[];
+            let ambientModules: string[];
 
             // If we are importing helpers, we need to add a synthetic reference to resolve the
             // helpers library.
@@ -1018,6 +1150,7 @@ namespace ts {
 
             file.imports = imports || emptyArray;
             file.moduleAugmentations = moduleAugmentations || emptyArray;
+            file.ambientModuleNames = ambientModules || emptyArray;
 
             return;
 
@@ -1053,6 +1186,10 @@ namespace ts {
                                 (moduleAugmentations || (moduleAugmentations = [])).push(moduleName);
                             }
                             else if (!inAmbientModule) {
+                                if (isDtsFile) {
+                                    // for global .d.ts files record name of ambient module
+                                    (ambientModules || (ambientModules = [])).push(moduleName.text);
+                                }
                                 // An AmbientExternalModuleDeclaration declares an external module.
                                 // This type of declaration is permitted only in the global module.
                                 // The StringLiteral must specify a top - level external module name.
@@ -1298,7 +1435,7 @@ namespace ts {
             if (file.imports.length || file.moduleAugmentations.length) {
                 file.resolvedModules = createMap<ResolvedModuleFull>();
                 const moduleNames = map(concatenate(file.imports, file.moduleAugmentations), getTextOfLiteral);
-                const resolutions = resolveModuleNamesWorker(moduleNames, getNormalizedAbsolutePath(file.fileName, currentDirectory));
+                const resolutions = resolveModuleNamesReusingOldState(moduleNames, getNormalizedAbsolutePath(file.fileName, currentDirectory), file);
                 Debug.assert(resolutions.length === moduleNames.length);
                 for (let i = 0; i < moduleNames.length; i++) {
                     const resolution = resolutions[i];
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 381289b133b49..e4c92c502a456 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2102,6 +2102,7 @@ namespace ts {
         /* @internal */ imports: LiteralExpression[];
         /* @internal */ moduleAugmentations: LiteralExpression[];
         /* @internal */ patternAmbientModules?: PatternAmbientModule[];
+        /* @internal */ ambientModuleNames: string[];
         // The synthesized identifier for an imported external helpers module.
         /* @internal */ externalHelpersModuleName?: Identifier;
     }
@@ -2296,6 +2297,8 @@ namespace ts {
         isOptionalParameter(node: ParameterDeclaration): boolean;
         getAmbientModules(): Symbol[];
 
+        /* @internal */ tryFindAmbientModuleWithoutAugmentations(moduleName: string): Symbol;
+
         // Should not be called directly.  Should only be accessed through the Program instance.
         /* @internal */ getDiagnostics(sourceFile?: SourceFile, cancellationToken?: CancellationToken): Diagnostic[];
         /* @internal */ getGlobalDiagnostics(): Diagnostic[];
diff --git a/src/harness/unittests/moduleResolution.ts b/src/harness/unittests/moduleResolution.ts
index 104d9f9e394eb..0e391445ebaff 100644
--- a/src/harness/unittests/moduleResolution.ts
+++ b/src/harness/unittests/moduleResolution.ts
@@ -1065,5 +1065,69 @@ import b = require("./moduleB");
             assert.equal(diagnostics2.length, 1, "expected one diagnostic");
             assert.equal(diagnostics1[0].messageText, diagnostics2[0].messageText, "expected one diagnostic");
         });
+
+        it ("Modules in the same .d.ts file are preferred to external files", () => {
+            const f = {
+                name: "/a/b/c/c/app.d.ts",
+                content: `
+                declare module "fs" {
+                    export interface Stat { id: number }
+                }
+                declare module "fs-client" {
+                    import { Stat } from "fs";
+                    export function foo(): Stat;
+                }`
+            };
+            const file = createSourceFile(f.name, f.content, ScriptTarget.ES2015);
+            const compilerHost: CompilerHost = {
+                fileExists : fileName => fileName === file.fileName,
+                getSourceFile: fileName => fileName === file.fileName ? file : undefined,
+                getDefaultLibFileName: () => "lib.d.ts",
+                writeFile: notImplemented,
+                getCurrentDirectory: () => "/",
+                getDirectories: () => [],
+                getCanonicalFileName: f => f.toLowerCase(),
+                getNewLine: () => "\r\n",
+                useCaseSensitiveFileNames: () => false,
+                readFile: fileName => fileName === file.fileName ? file.text : undefined,
+                resolveModuleNames() {
+                    assert(false, "resolveModuleNames should not be called");
+                    return undefined;
+                }
+            };
+            createProgram([f.name], {}, compilerHost);
+        });
+
+        it ("Modules in .ts file are not checked in the same file", () => {
+            const f = {
+                name: "/a/b/c/c/app.ts",
+                content: `
+                declare module "fs" {
+                    export interface Stat { id: number }
+                }
+                declare module "fs-client" {
+                    import { Stat } from "fs";
+                    export function foo(): Stat;
+                }`
+            };
+            const file = createSourceFile(f.name, f.content, ScriptTarget.ES2015);
+            const compilerHost: CompilerHost = {
+                fileExists : fileName => fileName === file.fileName,
+                getSourceFile: fileName => fileName === file.fileName ? file : undefined,
+                getDefaultLibFileName: () => "lib.d.ts",
+                writeFile: notImplemented,
+                getCurrentDirectory: () => "/",
+                getDirectories: () => [],
+                getCanonicalFileName: f => f.toLowerCase(),
+                getNewLine: () => "\r\n",
+                useCaseSensitiveFileNames: () => false,
+                readFile: fileName => fileName === file.fileName ? file.text : undefined,
+                resolveModuleNames(moduleNames: string[], _containingFile: string) {
+                    assert.deepEqual(moduleNames, ["fs"]);
+                    return [undefined];
+                }
+            };
+            createProgram([f.name], {}, compilerHost);
+        });
     });
 }
diff --git a/src/harness/unittests/reuseProgramStructure.ts b/src/harness/unittests/reuseProgramStructure.ts
index 215e05658a964..386e02e24507a 100644
--- a/src/harness/unittests/reuseProgramStructure.ts
+++ b/src/harness/unittests/reuseProgramStructure.ts
@@ -22,6 +22,11 @@ namespace ts {
 
     interface ProgramWithSourceTexts extends Program {
         sourceTexts?: NamedSourceText[];
+        host: TestCompilerHost;
+    }
+
+    interface TestCompilerHost extends CompilerHost {
+        getTrace(): string[];
     }
 
     class SourceText implements IScriptSnapshot {
@@ -101,10 +106,21 @@ namespace ts {
         return file;
     }
 
-    function createTestCompilerHost(texts: NamedSourceText[], target: ScriptTarget): CompilerHost {
-        const files = arrayToMap(texts, t => t.name, t => createSourceFileWithText(t.name, t.text, target));
+    function createTestCompilerHost(texts: NamedSourceText[], target: ScriptTarget, oldProgram?: ProgramWithSourceTexts): TestCompilerHost {
+        const files = arrayToMap(texts, t => t.name, t => {
+            if (oldProgram) {
+                const oldFile = <SourceFileWithText>oldProgram.getSourceFile(t.name);
+                if (oldFile && oldFile.sourceText.getVersion() === t.text.getVersion()) {
+                    return oldFile;
+                }
+            }
+            return createSourceFileWithText(t.name, t.text, target);
+        });
+        const trace: string[] = [];
 
         return {
+            trace: s => trace.push(s),
+            getTrace: () => trace,
             getSourceFile(fileName): SourceFile {
                 return files[fileName];
             },
@@ -130,23 +146,25 @@ namespace ts {
             fileExists: fileName => fileName in files,
             readFile: fileName => {
                 return fileName in files ? files[fileName].text : undefined;
-            }
+            },
         };
     }
 
-    function newProgram(texts: NamedSourceText[], rootNames: string[], options: CompilerOptions): Program {
+    function newProgram(texts: NamedSourceText[], rootNames: string[], options: CompilerOptions): ProgramWithSourceTexts {
         const host = createTestCompilerHost(texts, options.target);
         const program = <ProgramWithSourceTexts>createProgram(rootNames, options, host);
         program.sourceTexts = texts;
+        program.host = host;
         return program;
     }
 
-    function updateProgram(oldProgram: Program, rootNames: string[], options: CompilerOptions, updater: (files: NamedSourceText[]) => void) {
+    function updateProgram(oldProgram: ProgramWithSourceTexts, rootNames: string[], options: CompilerOptions, updater: (files: NamedSourceText[]) => void) {
         const texts: NamedSourceText[] = (<ProgramWithSourceTexts>oldProgram).sourceTexts.slice(0);
         updater(texts);
-        const host = createTestCompilerHost(texts, options.target);
+        const host = createTestCompilerHost(texts, options.target, oldProgram);
         const program = <ProgramWithSourceTexts>createProgram(rootNames, options, host, oldProgram);
         program.sourceTexts = texts;
+        program.host = host;
         return program;
     }
 
@@ -355,6 +373,112 @@ namespace ts {
             assert.isTrue(!program_3.structureIsReused);
             checkResolvedTypeDirectivesCache(program_1, "/a.ts", createMap({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
         });
+
+        it("can reuse ambient module declarations from non-modified files", () => {
+            const files = [
+                { name: "/a/b/app.ts", text: SourceText.New("", "import * as fs from 'fs'", "") },
+                { name: "/a/b/node.d.ts", text: SourceText.New("", "", "declare module 'fs' {}") }
+            ];
+            const options = { target: ScriptTarget.ES2015, traceResolution: true };
+            const program = newProgram(files, files.map(f => f.name), options);
+            assert.deepEqual(program.host.getTrace(),
+                [
+                    "======== Resolving module 'fs' from '/a/b/app.ts'. ========",
+                    "Module resolution kind is not specified, using 'Classic'.",
+                    "File '/a/b/fs.ts' does not exist.",
+                    "File '/a/b/fs.tsx' does not exist.",
+                    "File '/a/b/fs.d.ts' does not exist.",
+                    "File '/a/fs.ts' does not exist.",
+                    "File '/a/fs.tsx' does not exist.",
+                    "File '/a/fs.d.ts' does not exist.",
+                    "File '/fs.ts' does not exist.",
+                    "File '/fs.tsx' does not exist.",
+                    "File '/fs.d.ts' does not exist.",
+                    "File '/a/b/node_modules/@types/fs.ts' does not exist.",
+                    "File '/a/b/node_modules/@types/fs.tsx' does not exist.",
+                    "File '/a/b/node_modules/@types/fs.d.ts' does not exist.",
+                    "File '/a/b/node_modules/@types/fs/package.json' does not exist.",
+                    "File '/a/b/node_modules/@types/fs/index.ts' does not exist.",
+                    "File '/a/b/node_modules/@types/fs/index.tsx' does not exist.",
+                    "File '/a/b/node_modules/@types/fs/index.d.ts' does not exist.",
+                    "File '/a/node_modules/@types/fs.ts' does not exist.",
+                    "File '/a/node_modules/@types/fs.tsx' does not exist.",
+                    "File '/a/node_modules/@types/fs.d.ts' does not exist.",
+                    "File '/a/node_modules/@types/fs/package.json' does not exist.",
+                    "File '/a/node_modules/@types/fs/index.ts' does not exist.",
+                    "File '/a/node_modules/@types/fs/index.tsx' does not exist.",
+                    "File '/a/node_modules/@types/fs/index.d.ts' does not exist.",
+                    "File '/node_modules/@types/fs.ts' does not exist.",
+                    "File '/node_modules/@types/fs.tsx' does not exist.",
+                    "File '/node_modules/@types/fs.d.ts' does not exist.",
+                    "File '/node_modules/@types/fs/package.json' does not exist.",
+                    "File '/node_modules/@types/fs/index.ts' does not exist.",
+                    "File '/node_modules/@types/fs/index.tsx' does not exist.",
+                    "File '/node_modules/@types/fs/index.d.ts' does not exist.",
+                    "File '/a/b/fs.js' does not exist.",
+                    "File '/a/b/fs.jsx' does not exist.",
+                    "File '/a/fs.js' does not exist.",
+                    "File '/a/fs.jsx' does not exist.",
+                    "File '/fs.js' does not exist.",
+                    "File '/fs.jsx' does not exist.",
+                    "======== Module name 'fs' was not resolved. ========",
+                ], "should look for 'fs'");
+
+            const program_2 = updateProgram(program, program.getRootFileNames(), options, f => {
+                f[0].text = f[0].text.updateProgram("var x = 1;");
+            });
+            assert.deepEqual(program_2.host.getTrace(), [
+                "Module 'fs' was resolved as ambient module declared in '/a/b/node.d.ts' since this file was not modified."
+            ], "should reuse 'fs' since node.d.ts was not changed");
+
+            const program_3 = updateProgram(program_2, program_2.getRootFileNames(), options, f => {
+                f[0].text = f[0].text.updateProgram("var y = 1;");
+                f[1].text = f[1].text.updateProgram("declare var process: any");
+            });
+            assert.deepEqual(program_3.host.getTrace(),
+                [
+                    "======== Resolving module 'fs' from '/a/b/app.ts'. ========",
+                    "Module resolution kind is not specified, using 'Classic'.",
+                    "File '/a/b/fs.ts' does not exist.",
+                    "File '/a/b/fs.tsx' does not exist.",
+                    "File '/a/b/fs.d.ts' does not exist.",
+                    "File '/a/fs.ts' does not exist.",
+                    "File '/a/fs.tsx' does not exist.",
+                    "File '/a/fs.d.ts' does not exist.",
+                    "File '/fs.ts' does not exist.",
+                    "File '/fs.tsx' does not exist.",
+                    "File '/fs.d.ts' does not exist.",
+                    "File '/a/b/node_modules/@types/fs.ts' does not exist.",
+                    "File '/a/b/node_modules/@types/fs.tsx' does not exist.",
+                    "File '/a/b/node_modules/@types/fs.d.ts' does not exist.",
+                    "File '/a/b/node_modules/@types/fs/package.json' does not exist.",
+                    "File '/a/b/node_modules/@types/fs/index.ts' does not exist.",
+                    "File '/a/b/node_modules/@types/fs/index.tsx' does not exist.",
+                    "File '/a/b/node_modules/@types/fs/index.d.ts' does not exist.",
+                    "File '/a/node_modules/@types/fs.ts' does not exist.",
+                    "File '/a/node_modules/@types/fs.tsx' does not exist.",
+                    "File '/a/node_modules/@types/fs.d.ts' does not exist.",
+                    "File '/a/node_modules/@types/fs/package.json' does not exist.",
+                    "File '/a/node_modules/@types/fs/index.ts' does not exist.",
+                    "File '/a/node_modules/@types/fs/index.tsx' does not exist.",
+                    "File '/a/node_modules/@types/fs/index.d.ts' does not exist.",
+                    "File '/node_modules/@types/fs.ts' does not exist.",
+                    "File '/node_modules/@types/fs.tsx' does not exist.",
+                    "File '/node_modules/@types/fs.d.ts' does not exist.",
+                    "File '/node_modules/@types/fs/package.json' does not exist.",
+                    "File '/node_modules/@types/fs/index.ts' does not exist.",
+                    "File '/node_modules/@types/fs/index.tsx' does not exist.",
+                    "File '/node_modules/@types/fs/index.d.ts' does not exist.",
+                    "File '/a/b/fs.js' does not exist.",
+                    "File '/a/b/fs.jsx' does not exist.",
+                    "File '/a/fs.js' does not exist.",
+                    "File '/a/fs.jsx' does not exist.",
+                    "File '/fs.js' does not exist.",
+                    "File '/fs.jsx' does not exist.",
+                    "======== Module name 'fs' was not resolved. ========",
+                ], "should look for 'fs' again since node.d.ts was changed");
+
+        });
     });
 
     describe("host is optional", () => {
diff --git a/src/services/services.ts b/src/services/services.ts
index 8c11c707e5d60..8abcf8f76846c 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -472,6 +472,7 @@ namespace ts {
         public imports: LiteralExpression[];
         public moduleAugmentations: LiteralExpression[];
         private namedDeclarations: Map<Declaration[]>;
+        public ambientModuleNames: string[];
 
         constructor(kind: SyntaxKind, pos: number, end: number) {
             super(kind, pos, end);

From a7c18367cad6169428d1ed09bfcc8ce768d51035 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 2 Nov 2016 14:55:24 -0700
Subject: [PATCH 152/224] Parse, bind and check rest elements

---
 src/compiler/binder.ts               | 72 ++++++++++++++++----
 src/compiler/checker.ts              | 98 +++++++++++++++++-----------
 src/compiler/diagnosticMessages.json |  6 +-
 src/compiler/parser.ts               | 11 +++-
 src/compiler/types.ts                | 19 +++---
 src/compiler/utilities.ts            | 16 +++++
 6 files changed, 161 insertions(+), 61 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index b0c456a677068..a4d9a5a30ed02 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -1916,6 +1916,9 @@ namespace ts {
                     return bindParameter(<ParameterDeclaration>node);
                 case SyntaxKind.VariableDeclaration:
                 case SyntaxKind.BindingElement:
+                    if ((node as BindingElement).dotDotDotToken && node.parent.kind === SyntaxKind.ObjectBindingPattern) {
+                        emitFlags |= NodeFlags.HasRestAttribute;
+                    }
                     return bindVariableDeclarationOrBindingElement(<VariableDeclaration | BindingElement>node);
                 case SyntaxKind.PropertyDeclaration:
                 case SyntaxKind.PropertySignature:
@@ -1931,7 +1934,11 @@ namespace ts {
 
                 case SyntaxKind.SpreadElementExpression:
                 case SyntaxKind.JsxSpreadAttribute:
-                    emitFlags |= NodeFlags.HasSpreadAttribute;
+                    let root = container;
+                    while (root && root.kind !== SyntaxKind.BinaryExpression) {
+                        root = root.parent;
+                    }
+                    emitFlags |= root && isDestructuringAssignment(root) ? NodeFlags.HasRestAttribute : NodeFlags.HasSpreadAttribute;
                     return;
 
                 case SyntaxKind.CallSignature:
@@ -2542,10 +2549,13 @@ namespace ts {
         const operatorTokenKind = node.operatorToken.kind;
         const leftKind = node.left.kind;
 
-        if (operatorTokenKind === SyntaxKind.EqualsToken
-            && (leftKind === SyntaxKind.ObjectLiteralExpression
-                || leftKind === SyntaxKind.ArrayLiteralExpression)) {
-            // Destructuring assignments are ES6 syntax.
+        if (operatorTokenKind === SyntaxKind.EqualsToken && leftKind === SyntaxKind.ObjectLiteralExpression) {
+            // Destructuring object assignments with are ES2015 syntax
+            // and possibly ESNext if they contain rest
+            transformFlags |= TransformFlags.AssertESNext | TransformFlags.AssertES2015 | TransformFlags.AssertDestructuringAssignment;
+        }
+        else if (operatorTokenKind === SyntaxKind.EqualsToken && leftKind === SyntaxKind.ArrayLiteralExpression) {
+            // Destructuring assignments are ES2015 syntax.
             transformFlags |= TransformFlags.AssertES2015 | TransformFlags.AssertDestructuringAssignment;
         }
         else if (operatorTokenKind === SyntaxKind.AsteriskAsteriskToken
@@ -2579,6 +2589,11 @@ namespace ts {
             transformFlags |= TransformFlags.AssertTypeScript | TransformFlags.ContainsParameterPropertyAssignments;
         }
 
+        // parameters with object rest destructuring are ES Next syntax
+        if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+            transformFlags |= TransformFlags.AssertESNext;
+        }
+
         // If a parameter has an initializer, a binding pattern or a dotDotDot token, then
         // it is ES6 syntax and its container must emit default value assignments or parameter destructuring downlevel.
         if (subtreeFlags & TransformFlags.ContainsBindingPattern || initializer || dotDotDotToken) {
@@ -2812,6 +2827,11 @@ namespace ts {
                 transformFlags |= TransformFlags.AssertES2017;
             }
 
+            // function declarations with object rest destructuring are ES Next syntax
+            if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+                transformFlags |= TransformFlags.AssertESNext;
+            }
+
             // If a FunctionDeclaration's subtree has marked the container as needing to capture the
             // lexical this, or the function contains parameters with initializers, then this node is
             // ES6 syntax.
@@ -2849,6 +2869,12 @@ namespace ts {
             transformFlags |= TransformFlags.AssertES2017;
         }
 
+        // function expressions with object rest destructuring are ES Next syntax
+        if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+            transformFlags |= TransformFlags.AssertESNext;
+        }
+
+
         // If a FunctionExpression's subtree has marked the container as needing to capture the
         // lexical this, or the function contains parameters with initializers, then this node is
         // ES6 syntax.
@@ -2886,6 +2912,11 @@ namespace ts {
             transformFlags |= TransformFlags.AssertES2017;
         }
 
+        // arrow functions with object rest destructuring are ES Next syntax
+        if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+            transformFlags |= TransformFlags.AssertESNext;
+        }
+
         // If an ArrowFunction contains a lexical this, its container must capture the lexical this.
         if (subtreeFlags & TransformFlags.ContainsLexicalThis) {
             transformFlags |= TransformFlags.ContainsCapturedLexicalThis;
@@ -2914,8 +2945,13 @@ namespace ts {
         let transformFlags = subtreeFlags;
         const nameKind = node.name.kind;
 
-        // A VariableDeclaration with a binding pattern is ES6 syntax.
-        if (nameKind === SyntaxKind.ObjectBindingPattern || nameKind === SyntaxKind.ArrayBindingPattern) {
+        // A VariableDeclaration with an object binding pattern is ES2015 syntax
+        // and possibly ESNext syntax if it contains an object binding pattern
+        if (nameKind === SyntaxKind.ObjectBindingPattern) {
+            transformFlags |= TransformFlags.AssertESNext | TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
+        }
+        // A VariableDeclaration with an object binding pattern is ES2015 syntax.
+        else if (nameKind === SyntaxKind.ArrayBindingPattern) {
             transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
         }
 
@@ -3056,6 +3092,10 @@ namespace ts {
                 transformFlags |= TransformFlags.AssertJsx;
                 break;
 
+            case SyntaxKind.ForOfStatement:
+                // for-of might be ESNext if it has a rest destructuring
+                transformFlags |= TransformFlags.AssertESNext;
+                // FALLTHROUGH
             case SyntaxKind.NoSubstitutionTemplateLiteral:
             case SyntaxKind.TemplateHead:
             case SyntaxKind.TemplateMiddle:
@@ -3063,7 +3103,6 @@ namespace ts {
             case SyntaxKind.TemplateExpression:
             case SyntaxKind.TaggedTemplateExpression:
             case SyntaxKind.ShorthandPropertyAssignment:
-            case SyntaxKind.ForOfStatement:
             case SyntaxKind.StaticKeyword:
                 // These nodes are ES6 syntax.
                 transformFlags |= TransformFlags.AssertES2015;
@@ -3129,10 +3168,16 @@ namespace ts {
 
             case SyntaxKind.SpreadExpression:
             case SyntaxKind.SpreadElementExpression:
-                // This node is ES6 or ES future syntax, but is handled by a containing node.
+                // This node is ES2015 or ES next syntax, but is handled by a containing node.
                 transformFlags |= TransformFlags.ContainsSpreadExpression;
                 break;
 
+            case SyntaxKind.BindingElement:
+                if ((node as BindingElement).dotDotDotToken) {
+                    // this node is ES2015 or ES next syntax, but is handled by a containing node.
+                    transformFlags |= TransformFlags.ContainsSpreadExpression;
+                }
+
             case SyntaxKind.SuperKeyword:
                 // This node is ES6 syntax.
                 transformFlags |= TransformFlags.AssertES2015;
@@ -3145,8 +3190,13 @@ namespace ts {
 
             case SyntaxKind.ObjectBindingPattern:
             case SyntaxKind.ArrayBindingPattern:
-                // These nodes are ES6 syntax.
-                transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
+                // These nodes are ES2015 or ES Next syntax.
+                if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+                    transformFlags |= TransformFlags.AssertESNext | TransformFlags.ContainsBindingPattern;
+                }
+                else {
+                    transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
+                }
                 break;
 
             case SyntaxKind.Decorator:
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 5447e652f08fe..1c4a135088326 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2245,7 +2245,7 @@ namespace ts {
                         writeUnionOrIntersectionType(<UnionOrIntersectionType>type, nextFlags);
                     }
                     else if (type.flags & TypeFlags.Spread) {
-                        writeSpreadType(<SpreadType>type);
+                        writeSpreadType(type as SpreadType);
                     }
                     else if (getObjectFlags(type) & ObjectFlags.Anonymous) {
                         writeAnonymousType(<ObjectType>type, nextFlags);
@@ -3028,26 +3028,31 @@ namespace ts {
             return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node, /*includeOptionality*/ false);
         }
 
-        function getTextOfPropertyName(name: PropertyName): string {
-            switch (name.kind) {
-                case SyntaxKind.Identifier:
-                    return (<Identifier>name).text;
-                case SyntaxKind.StringLiteral:
-                case SyntaxKind.NumericLiteral:
-                    return (<LiteralExpression>name).text;
-                case SyntaxKind.ComputedPropertyName:
-                    if (isStringOrNumericLiteral((<ComputedPropertyName>name).expression.kind)) {
-                        return (<LiteralExpression>(<ComputedPropertyName>name).expression).text;
-                    }
-            }
-
-            return undefined;
-        }
-
         function isComputedNonLiteralName(name: PropertyName): boolean {
             return name.kind === SyntaxKind.ComputedPropertyName && !isStringOrNumericLiteral((<ComputedPropertyName>name).expression.kind);
         }
 
+        function getRestType(source: Type, properties: PropertyName[], symbol: Symbol): Type {
+            Debug.assert(!!(source.flags & TypeFlags.Object), "Rest types only support object types right now.");
+            const members = createMap<Symbol>();
+            const names = createMap<true>();
+            for (const name of properties) {
+                names[getTextOfPropertyName(name)] = true;
+            }
+            for (const prop of getPropertiesOfType(source)) {
+                const inNamesToRemove = prop.name in names;
+                const isPrivate = getDeclarationModifierFlagsFromSymbol(prop) & (ModifierFlags.Private | ModifierFlags.Protected);
+                const isMethod = prop.flags & SymbolFlags.Method;
+                const isSetOnlyAccessor = prop.flags & SymbolFlags.SetAccessor && !(prop.flags & SymbolFlags.GetAccessor);
+                if (!inNamesToRemove && !isPrivate && !isMethod && !isSetOnlyAccessor) {
+                    members[prop.name] = prop;
+                }
+            }
+            const stringIndexInfo = getIndexInfoOfType(source, IndexKind.String);
+            const numberIndexInfo = getIndexInfoOfType(source, IndexKind.Number);
+            return createAnonymousType(symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
+        }
+
         /** Return the inferred type for a binding element */
         function getTypeForBindingElement(declaration: BindingElement): Type {
             const pattern = <BindingPattern>declaration.parent;
@@ -3068,26 +3073,41 @@ namespace ts {
 
             let type: Type;
             if (pattern.kind === SyntaxKind.ObjectBindingPattern) {
-                // Use explicitly specified property name ({ p: xxx } form), or otherwise the implied name ({ p } form)
-                const name = declaration.propertyName || <Identifier>declaration.name;
-                if (isComputedNonLiteralName(name)) {
-                    // computed properties with non-literal names are treated as 'any'
-                    return anyType;
-                }
-                if (declaration.initializer) {
-                    getContextualType(declaration.initializer);
+                if (declaration.dotDotDotToken) {
+                    if (!(parentType.flags & TypeFlags.Object)) {
+                        error(declaration, Diagnostics.Rest_types_may_only_be_created_from_object_types);
+                        return unknownType;
+                    }
+                    const literalMembers: PropertyName[] = [];
+                    for (const element of pattern.elements) {
+                        if (element.kind !== SyntaxKind.OmittedExpression && !(element as BindingElement).dotDotDotToken) {
+                            literalMembers.push(element.propertyName || element.name as Identifier);
+                        }
+                    }
+                    type = getRestType(parentType, literalMembers, declaration.symbol);
                 }
+                else {
+                    // Use explicitly specified property name ({ p: xxx } form), or otherwise the implied name ({ p } form)
+                    const name = declaration.propertyName || <Identifier>declaration.name;
+                    if (isComputedNonLiteralName(name)) {
+                        // computed properties with non-literal names are treated as 'any'
+                        return anyType;
+                    }
+                    if (declaration.initializer) {
+                        getContextualType(declaration.initializer);
+                    }
 
-                // Use type of the specified property, or otherwise, for a numeric name, the type of the numeric index signature,
-                // or otherwise the type of the string index signature.
-                const text = getTextOfPropertyName(name);
+                    // Use type of the specified property, or otherwise, for a numeric name, the type of the numeric index signature,
+                    // or otherwise the type of the string index signature.
+                    const text = getTextOfPropertyName(name);
 
-                type = getTypeOfPropertyOfType(parentType, text) ||
-                    isNumericLiteralName(text) && getIndexTypeOfType(parentType, IndexKind.Number) ||
-                    getIndexTypeOfType(parentType, IndexKind.String);
-                if (!type) {
-                    error(name, Diagnostics.Type_0_has_no_property_1_and_no_string_index_signature, typeToString(parentType), declarationNameToString(name));
-                    return unknownType;
+                    type = getTypeOfPropertyOfType(parentType, text) ||
+                        isNumericLiteralName(text) && getIndexTypeOfType(parentType, IndexKind.Number) ||
+                        getIndexTypeOfType(parentType, IndexKind.String);
+                    if (!type) {
+                        error(name, Diagnostics.Type_0_has_no_property_1_and_no_string_index_signature, typeToString(parentType), declarationNameToString(name));
+                        return unknownType;
+                    }
                 }
             }
             else {
@@ -3295,8 +3315,8 @@ namespace ts {
             let hasComputedProperties = false;
             forEach(pattern.elements, e => {
                 const name = e.propertyName || <Identifier>e.name;
-                if (isComputedNonLiteralName(name)) {
-                    // do not include computed properties in the implied type
+                if (isComputedNonLiteralName(name) || e.dotDotDotToken) {
+                    // do not include computed properties or rests in the implied type
                     hasComputedProperties = true;
                     return;
                 }
@@ -14097,7 +14117,7 @@ namespace ts {
                     error(name, Diagnostics.Type_0_has_no_property_1_and_no_string_index_signature, typeToString(objectLiteralType), declarationNameToString(name));
                 }
             }
-            else {
+            else if (property.kind !== SyntaxKind.SpreadElementExpression) {
                 error(property, Diagnostics.Property_assignment_expected);
             }
         }
@@ -14143,7 +14163,7 @@ namespace ts {
                 }
                 else {
                     if (elementIndex < elements.length - 1) {
-                        error(element, Diagnostics.A_rest_element_must_be_last_in_an_array_destructuring_pattern);
+                        error(element, Diagnostics.A_rest_element_must_be_last_in_a_destructuring_pattern);
                     }
                     else {
                         const restExpression = (<SpreadExpression>element).expression;
@@ -21058,7 +21078,7 @@ namespace ts {
             if (node.dotDotDotToken) {
                 const elements = (<BindingPattern>node.parent).elements;
                 if (node !== lastOrUndefined(elements)) {
-                    return grammarErrorOnNode(node, Diagnostics.A_rest_element_must_be_last_in_an_array_destructuring_pattern);
+                    return grammarErrorOnNode(node, Diagnostics.A_rest_element_must_be_last_in_a_destructuring_pattern);
                 }
 
                 if (node.name.kind === SyntaxKind.ArrayBindingPattern || node.name.kind === SyntaxKind.ObjectBindingPattern) {
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 1d45e96cb6f6b..5b6d958061eef 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1455,7 +1455,7 @@
         "category": "Error",
         "code": 2461
     },
-    "A rest element must be last in an array destructuring pattern": {
+    "A rest element must be last in a destructuring pattern": {
         "category": "Error",
         "code": 2462
     },
@@ -1991,6 +1991,10 @@
         "category": "Error",
         "code": 2699
     },
+    "Rest types may only be created from object types.": {
+        "category": "Error",
+        "code": 2700
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index ac41d78bb1232..43182ca83b667 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -1274,8 +1274,10 @@ namespace ts {
                     return token() === SyntaxKind.OpenBracketToken || isLiteralPropertyName();
                 case ParsingContext.ObjectLiteralMembers:
                     return token() === SyntaxKind.OpenBracketToken || token() === SyntaxKind.AsteriskToken || token() === SyntaxKind.DotDotDotToken || isLiteralPropertyName();
+                case ParsingContext.RestProperties:
+                    return isLiteralPropertyName();
                 case ParsingContext.ObjectBindingElements:
-                    return token() === SyntaxKind.OpenBracketToken || isLiteralPropertyName();
+                    return token() === SyntaxKind.OpenBracketToken || token() === SyntaxKind.DotDotDotToken || isLiteralPropertyName();
                 case ParsingContext.HeritageClauseElement:
                     // If we see { } then only consume it as an expression if it is followed by , or {
                     // That way we won't consume the body of a class in its heritage clause.
@@ -1402,6 +1404,7 @@ namespace ts {
                 case ParsingContext.ArrayBindingElements:
                     return token() === SyntaxKind.CloseBracketToken;
                 case ParsingContext.Parameters:
+                case ParsingContext.RestProperties:
                     // Tokens other than ')' and ']' (the latter for index signatures) are here for better error recovery
                     return token() === SyntaxKind.CloseParenToken || token() === SyntaxKind.CloseBracketToken /*|| token === SyntaxKind.OpenBraceToken*/;
                 case ParsingContext.TypeArguments:
@@ -1587,6 +1590,9 @@ namespace ts {
                 case ParsingContext.Parameters:
                     return isReusableParameter(node);
 
+                case ParsingContext.RestProperties:
+                    return false;
+
                 // Any other lists we do not care about reusing nodes in.  But feel free to add if
                 // you can do so safely.  Danger areas involve nodes that may involve speculative
                 // parsing.  If speculative parsing is involved with the node, then the range the
@@ -1784,6 +1790,7 @@ namespace ts {
                 case ParsingContext.BlockStatements: return Diagnostics.Declaration_or_statement_expected;
                 case ParsingContext.SwitchClauses: return Diagnostics.case_or_default_expected;
                 case ParsingContext.SwitchClauseStatements: return Diagnostics.Statement_expected;
+                case ParsingContext.RestProperties: // fallthrough
                 case ParsingContext.TypeMembers: return Diagnostics.Property_or_signature_expected;
                 case ParsingContext.ClassMembers: return Diagnostics.Unexpected_token_A_constructor_method_accessor_or_property_was_expected;
                 case ParsingContext.EnumMembers: return Diagnostics.Enum_member_expected;
@@ -4890,6 +4897,7 @@ namespace ts {
 
         function parseObjectBindingElement(): BindingElement {
             const node = <BindingElement>createNode(SyntaxKind.BindingElement);
+            node.dotDotDotToken = parseOptionalToken(SyntaxKind.DotDotDotToken);
             const tokenIsIdentifier = isIdentifier();
             const propertyName = parsePropertyName();
             if (tokenIsIdentifier && token() !== SyntaxKind.ColonToken) {
@@ -5834,6 +5842,7 @@ namespace ts {
             JsxChildren,               // Things between opening and closing JSX tags
             ArrayLiteralMembers,       // Members in array literal
             Parameters,                // Parameters in parameter list
+            RestProperties,            // Property names in a rest type list
             TypeParameters,            // Type parameters in type parameter list
             TypeArguments,             // Type arguments in type argument list
             TupleElementTypes,         // Element types in tuple element type list
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index ba5e6b2db9971..b9d223931fc44 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -422,14 +422,15 @@ namespace ts {
         HasParamDecorators = 1 << 12, // If the file has parameter decorators (initialized by binding)
         HasAsyncFunctions =  1 << 13, // If the file has async functions (initialized by binding)
         HasSpreadAttribute = 1 << 14, // If the file as JSX spread attributes (initialized by binding)
-        DisallowInContext =  1 << 15, // If node was parsed in a context where 'in-expressions' are not allowed
-        YieldContext =       1 << 16, // If node was parsed in the 'yield' context created when parsing a generator
-        DecoratorContext =   1 << 17, // If node was parsed as part of a decorator
-        AwaitContext =       1 << 18, // If node was parsed in the 'await' context created when parsing an async function
-        ThisNodeHasError =   1 << 19, // If the parser encountered an error when parsing the code that created this node
-        JavaScriptFile =     1 << 20, // If node was parsed in a JavaScript
-        ThisNodeOrAnySubNodesHasError = 1 << 21, // If this node or any of its children had an error
-        HasAggregatedChildData = 1 << 22, // If we've computed data from children and cached it in this node
+        HasRestAttribute =   1 << 15, // If the file has object destructure elements
+        DisallowInContext =  1 << 16, // If node was parsed in a context where 'in-expressions' are not allowed
+        YieldContext =       1 << 17, // If node was parsed in the 'yield' context created when parsing a generator
+        DecoratorContext =   1 << 18, // If node was parsed as part of a decorator
+        AwaitContext =       1 << 19, // If node was parsed in the 'await' context created when parsing an async function
+        ThisNodeHasError =   1 << 20, // If the parser encountered an error when parsing the code that created this node
+        JavaScriptFile =     1 << 21, // If node was parsed in a JavaScript
+        ThisNodeOrAnySubNodesHasError = 1 << 22, // If this node or any of its children had an error
+        HasAggregatedChildData = 1 << 23, // If we've computed data from children and cached it in this node
 
         BlockScoped = Let | Const,
 
@@ -651,7 +652,7 @@ namespace ts {
     export interface BindingElement extends Declaration {
         kind: SyntaxKind.BindingElement;
         propertyName?: PropertyName;        // Binding property name (in object binding pattern)
-        dotDotDotToken?: DotDotDotToken;              // Present on rest binding element
+        dotDotDotToken?: DotDotDotToken;    // Present on rest element (in object binding pattern)
         name: BindingName;                  // Declared binding element name
         initializer?: Expression;           // Optional initializer
     }
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index cd3e6ab9575b5..67742347568f4 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -485,6 +485,22 @@ namespace ts {
         return getFullWidth(name) === 0 ? "(Missing)" : getTextOfNode(name);
     }
 
+    export function getTextOfPropertyName(name: PropertyName): string {
+        switch (name.kind) {
+        case SyntaxKind.Identifier:
+            return (<Identifier>name).text;
+        case SyntaxKind.StringLiteral:
+        case SyntaxKind.NumericLiteral:
+            return (<LiteralExpression>name).text;
+        case SyntaxKind.ComputedPropertyName:
+            if (isStringOrNumericLiteral((<ComputedPropertyName>name).expression.kind)) {
+                return (<LiteralExpression>(<ComputedPropertyName>name).expression).text;
+            }
+        }
+
+        return undefined;
+    }
+
     export function entityNameToString(name: EntityNameOrEntityNameExpression): string {
         switch (name.kind) {
             case SyntaxKind.Identifier:

From e3a08ed663446753b1d52a8c1f036560072a4e29 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 2 Nov 2016 14:56:01 -0700
Subject: [PATCH 153/224] Downlevel emit of rest elements

---
 src/compiler/emitter.ts                    |  15 +
 src/compiler/transformers/destructuring.ts | 193 ++++++++--
 src/compiler/transformers/esnext.ts        | 428 +++++++++++++++++++++
 3 files changed, 596 insertions(+), 40 deletions(-)

diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 0ee598c507aed..c89fa1f155043 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -42,6 +42,15 @@ var __assign = (this && this.__assign) || Object.assign || function(t) {
     return t;
 };`;
 
+        const restHelper = `
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
+        t[p] = s[p];
+    return t;
+};`;
+
         // emit output for the __decorate helper function
         const decorateHelper = `
 var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
@@ -226,6 +235,7 @@ const _super = (function (geti, seti) {
         let currentFileIdentifiers: Map<string>;
         let extendsEmitted: boolean;
         let assignEmitted: boolean;
+        let restEmitted: boolean;
         let decorateEmitted: boolean;
         let paramEmitted: boolean;
         let awaiterEmitted: boolean;
@@ -2210,6 +2220,11 @@ const _super = (function (geti, seti) {
                 assignEmitted = true;
             }
 
+            if (!restEmitted && node.flags & NodeFlags.HasRestAttribute) {
+                writeLines(restHelper);
+                restEmitted = true;
+            }
+
             if (!decorateEmitted && node.flags & NodeFlags.HasDecorators) {
                 writeLines(decorateHelper);
                 if (compilerOptions.emitDecoratorMetadata) {
diff --git a/src/compiler/transformers/destructuring.ts b/src/compiler/transformers/destructuring.ts
index 89beade577d80..bac8e99420115 100644
--- a/src/compiler/transformers/destructuring.ts
+++ b/src/compiler/transformers/destructuring.ts
@@ -17,7 +17,8 @@ namespace ts {
         node: BinaryExpression,
         needsValue: boolean,
         recordTempVariable: (node: Identifier) => void,
-        visitor?: (node: Node) => VisitResult<Node>): Expression {
+        visitor?: (node: Node) => VisitResult<Node>,
+        transformRest?: boolean): Expression {
 
         if (isEmptyObjectLiteralOrArrayLiteral(node.left)) {
             const right = node.right;
@@ -51,7 +52,7 @@ namespace ts {
             location = value;
         }
 
-        flattenDestructuring(node, value, location, emitAssignment, emitTempVariableAssignment, visitor);
+        flattenDestructuring(node, value, location, emitAssignment, emitTempVariableAssignment, emitRestAssignment, transformRest, visitor);
 
         if (needsValue) {
             expressions.push(value);
@@ -61,7 +62,7 @@ namespace ts {
         aggregateTransformFlags(expression);
         return expression;
 
-        function emitAssignment(name: Identifier, value: Expression, location: TextRange) {
+        function emitAssignment(name: Identifier | ObjectLiteralExpression, value: Expression, location: TextRange) {
             const expression = createAssignment(name, value, location);
 
             // NOTE: this completely disables source maps, but aligns with the behavior of
@@ -77,6 +78,10 @@ namespace ts {
             emitAssignment(name, value, location);
             return name;
         }
+
+        function emitRestAssignment(elements: ObjectLiteralElementLike[], value: Expression, location: TextRange) {
+            emitAssignment(createObjectLiteral(elements), value, location);
+        }
     }
 
     /**
@@ -89,14 +94,15 @@ namespace ts {
     export function flattenParameterDestructuring(
         node: ParameterDeclaration,
         value: Expression,
-        visitor?: (node: Node) => VisitResult<Node>) {
+        visitor?: (node: Node) => VisitResult<Node>,
+        transformRest?: boolean) {
         const declarations: VariableDeclaration[] = [];
 
-        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, visitor);
+        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, emitRestAssignment, transformRest, visitor);
 
         return declarations;
 
-        function emitAssignment(name: Identifier, value: Expression, location: TextRange) {
+        function emitAssignment(name: Identifier | BindingPattern, value: Expression, location: TextRange) {
             const declaration = createVariableDeclaration(name, /*type*/ undefined, value, location);
 
             // NOTE: this completely disables source maps, but aligns with the behavior of
@@ -112,6 +118,10 @@ namespace ts {
             emitAssignment(name, value, location);
             return name;
         }
+
+        function emitRestAssignment(elements: BindingElement[], value: Expression, location: TextRange) {
+            emitAssignment(createObjectBindingPattern(elements), value, location);
+        }
     }
 
     /**
@@ -125,15 +135,16 @@ namespace ts {
         node: VariableDeclaration,
         value?: Expression,
         visitor?: (node: Node) => VisitResult<Node>,
-        recordTempVariable?: (node: Identifier) => void) {
+        recordTempVariable?: (node: Identifier) => void,
+        transformRest?: boolean) {
         const declarations: VariableDeclaration[] = [];
 
         let pendingAssignments: Expression[];
-        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, visitor);
+        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, emitRestAssignment, transformRest, visitor);
 
         return declarations;
 
-        function emitAssignment(name: Identifier, value: Expression, location: TextRange, original: Node) {
+        function emitAssignment(name: Identifier | BindingPattern, value: Expression, location: TextRange, original: Node) {
             if (pendingAssignments) {
                 pendingAssignments.push(value);
                 value = inlineExpressions(pendingAssignments);
@@ -167,6 +178,10 @@ namespace ts {
             }
             return name;
         }
+
+        function emitRestAssignment(elements: BindingElement[], value: Expression, location: TextRange, original: Node) {
+            emitAssignment(createObjectBindingPattern(elements), value, location, original);
+        }
     }
 
     /**
@@ -186,15 +201,17 @@ namespace ts {
 
         const pendingAssignments: Expression[] = [];
 
-        flattenDestructuring(node, /*value*/ undefined, node, emitAssignment, emitTempVariableAssignment, visitor);
+        flattenDestructuring(node, /*value*/ undefined, node, emitAssignment, emitTempVariableAssignment, emitRestAssignment, /*transformRest*/ false, visitor);
 
         const expression = inlineExpressions(pendingAssignments);
         aggregateTransformFlags(expression);
         return expression;
 
-        function emitAssignment(name: Identifier, value: Expression, location: TextRange, original: Node) {
+        function emitAssignment(name: Identifier | ObjectLiteralExpression, value: Expression, location: TextRange, original: Node) {
             const expression = createAssignmentCallback
-                ? createAssignmentCallback(name, value, location)
+                ? createAssignmentCallback(name.kind === SyntaxKind.Identifier ? name : emitTempVariableAssignment(name, location),
+                                           value,
+                                           location)
                 : createAssignment(name, value, location);
 
             emitPendingAssignment(expression, original);
@@ -206,6 +223,10 @@ namespace ts {
             return name;
         }
 
+        function emitRestAssignment(elements: ObjectLiteralElementLike[], value: Expression, location: TextRange, original: Node) {
+            emitAssignment(createObjectLiteral(elements), value, location, original);
+        }
+
         function emitPendingAssignment(expression: Expression, original: Node) {
             expression.original = original;
 
@@ -223,6 +244,8 @@ namespace ts {
         location: TextRange,
         emitAssignment: (name: Identifier, value: Expression, location: TextRange, original: Node) => void,
         emitTempVariableAssignment: (value: Expression, location: TextRange) => Identifier,
+        emitRestAssignment: (elements: (ObjectLiteralElementLike[] | BindingElement[]), value: Expression, location: TextRange, original: Node) => void,
+        transformRest: boolean,
         visitor?: (node: Node) => VisitResult<Node>) {
         if (value && visitor) {
             value = visitNode(value, visitor, isExpression);
@@ -284,14 +307,39 @@ namespace ts {
                 value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ true, location, emitTempVariableAssignment);
             }
 
-            for (const p of properties) {
+            let es2015: ObjectLiteralElementLike[] = [];
+            for (let i = 0; i < properties.length; i++) {
+                const p = properties[i];
                 if (p.kind === SyntaxKind.PropertyAssignment || p.kind === SyntaxKind.ShorthandPropertyAssignment) {
-                    const propName = <Identifier | LiteralExpression>(<PropertyAssignment>p).name;
-                    const target = p.kind === SyntaxKind.ShorthandPropertyAssignment ? <ShorthandPropertyAssignment>p : (<PropertyAssignment>p).initializer || propName;
-                    // Assignment for target = value.propName should highligh whole property, hence use p as source map node
-                    emitDestructuringAssignment(target, createDestructuringPropertyAccess(value, propName), p);
+                    if (!transformRest || p.transformFlags & TransformFlags.ContainsSpreadExpression) {
+                        if (es2015.length) {
+                            emitRestAssignment(es2015, value, location, target);
+                            es2015 = [];
+                        }
+                        const propName = <Identifier | LiteralExpression>(<PropertyAssignment>p).name;
+                        const bindingTarget = p.kind === SyntaxKind.ShorthandPropertyAssignment ? <ShorthandPropertyAssignment>p : (<PropertyAssignment>p).initializer || propName;
+                        // Assignment for bindingTarget = value.propName should highlight whole property, hence use p as source map node
+                        emitDestructuringAssignment(bindingTarget, createDestructuringPropertyAccess(value, propName), p);
+                    }
+                    else {
+                        es2015.push(p);
+                    }
+                }
+                else if (i === properties.length - 1 && p.kind === SyntaxKind.SpreadElementExpression) {
+                    Debug.assert((p as SpreadElementExpression).expression.kind === SyntaxKind.Identifier);
+                    if (es2015.length) {
+                        emitRestAssignment(es2015, value, location, target);
+                        es2015 = [];
+                    }
+                    const propName = (p as SpreadElementExpression).expression as Identifier;
+                    const restCall = createRestCall(value, target.properties, p => p.name, target);
+                    emitDestructuringAssignment(propName, restCall, p);
                 }
             }
+            if (es2015.length) {
+                emitRestAssignment(es2015, value, location, target);
+                es2015 = [];
+            }
         }
 
         function emitArrayLiteralAssignment(target: ArrayLiteralExpression, value: Expression, location: TextRange) {
@@ -318,10 +366,31 @@ namespace ts {
             }
         }
 
+        /** Given value: o, propName: p, pattern: { a, b, ...p } from the original statement
+         * `{ a, b, ...p } = o`, create `p = __rest(o, ["a", "b"]);`*/
+        function createRestCall<T extends Node>(value: Expression, elements: T[], getPropertyName: (element: T) => PropertyName, location: TextRange): Expression {
+            const propertyNames: LiteralExpression[] = [];
+            for (let i = 0; i < elements.length - 1; i++) {
+                if (isOmittedExpression(elements[i])) {
+                    continue;
+                }
+                const str = <StringLiteral>createSynthesizedNode(SyntaxKind.StringLiteral);
+                str.pos = location.pos;
+                str.end = location.end;
+                str.text = getTextOfPropertyName(getPropertyName(elements[i]));
+                propertyNames.push(str);
+            }
+            const args = createSynthesizedNodeArray([value, createArrayLiteral(propertyNames, location)]);
+            return createCall(createIdentifier("__rest"), undefined, args);
+        }
+
         function emitBindingElement(target: VariableDeclaration | ParameterDeclaration | BindingElement, value: Expression) {
             // Any temporary assignments needed to emit target = value should point to target
             const initializer = visitor ? visitNode(target.initializer, visitor, isExpression) : target.initializer;
-            if (initializer) {
+            if (transformRest) {
+                value = value || initializer;
+            }
+            else if (initializer) {
                 // Combine value and initializer
                 value = value ? createDefaultValueCheck(value, initializer, target) : initializer;
             }
@@ -331,9 +400,11 @@ namespace ts {
             }
 
             const name = target.name;
-            if (isBindingPattern(name)) {
-                const elements = name.elements;
-                const numElements = elements.length;
+            if (!isBindingPattern(name)) {
+                emitAssignment(name, value, target, target);
+            }
+            else {
+                const numElements = name.elements.length;
                 if (numElements !== 1) {
                     // For anything other than a single-element destructuring we need to generate a temporary
                     // to ensure value is evaluated exactly once. Additionally, if we have zero elements
@@ -341,29 +412,71 @@ namespace ts {
                     // so in that case, we'll intentionally create that temporary.
                     value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ numElements !== 0, target, emitTempVariableAssignment);
                 }
-                for (let i = 0; i < numElements; i++) {
-                    const element = elements[i];
-                    if (isOmittedExpression(element)) {
-                        continue;
-                    }
-                    else if (name.kind === SyntaxKind.ObjectBindingPattern) {
-                        // Rewrite element to a declaration with an initializer that fetches property
-                        const propName = element.propertyName || <Identifier>element.name;
-                        emitBindingElement(element, createDestructuringPropertyAccess(value, propName));
+                if (name.kind === SyntaxKind.ArrayBindingPattern) {
+                    emitArrayBindingElement(name, value);
+                }
+                else {
+                    emitObjectBindingElement(target, value);
+                }
+            }
+        }
+
+        function emitArrayBindingElement(name: BindingPattern, value: Expression) {
+            const elements = name.elements;
+            const numElements = elements.length;
+            for (let i = 0; i < numElements; i++) {
+                const element = elements[i];
+                if (isOmittedExpression(element)) {
+                    continue;
+                }
+                if (!element.dotDotDotToken) {
+                    // Rewrite element to a declaration that accesses array element at index i
+                    emitBindingElement(element, createElementAccess(value, i));
+                }
+                else if (i === numElements - 1) {
+                    emitBindingElement(element, createArraySlice(value, i));
+                }
+            }
+        }
+
+        function emitObjectBindingElement(target: VariableDeclaration | ParameterDeclaration | BindingElement, value: Expression) {
+            const name = target.name as BindingPattern;
+            const elements = name.elements;
+            const numElements = elements.length;
+            let es2015: BindingElement[] = [];
+            for (let i = 0; i < numElements; i++) {
+                const element = elements[i];
+                if (isOmittedExpression(element)) {
+                    continue;
+                }
+                if (i === numElements - 1 && element.dotDotDotToken) {
+                    if (es2015.length) {
+                        emitRestAssignment(es2015, value, target, target);
+                        es2015 = [];
                     }
-                    else {
-                        if (!element.dotDotDotToken) {
-                            // Rewrite element to a declaration that accesses array element at index i
-                            emitBindingElement(element, createElementAccess(value, i));
-                        }
-                        else if (i === numElements - 1) {
-                            emitBindingElement(element, createArraySlice(value, i));
-                        }
+                    const restCall = createRestCall(value,
+                                                    name.elements,
+                                                    element => (element as BindingElement).propertyName || <Identifier>(element as BindingElement).name,
+                                                    name);
+                    emitBindingElement(element, restCall);
+                }
+                else if (!transformRest || element.transformFlags & TransformFlags.ContainsSpreadExpression) {
+                    if (es2015.length) {
+                        emitRestAssignment(es2015, value, target, target);
+                        es2015 = [];
                     }
+                    // Rewrite element to a declaration with an initializer that fetches property
+                    const propName = element.propertyName || <Identifier>element.name;
+                    emitBindingElement(element, createDestructuringPropertyAccess(value, propName));
+                }
+                else {
+                    // do not emit until we have a complete bundle of ES2015 syntax
+                    es2015.push(element);
                 }
             }
-            else {
-                emitAssignment(name, value, target, target);
+            if (es2015.length) {
+                emitRestAssignment(es2015, value, target, target);
+                es2015 = [];
             }
         }
 
diff --git a/src/compiler/transformers/esnext.ts b/src/compiler/transformers/esnext.ts
index 1a8ed7da5eb4a..a85098f03b6d9 100644
--- a/src/compiler/transformers/esnext.ts
+++ b/src/compiler/transformers/esnext.ts
@@ -4,9 +4,16 @@
 /*@internal*/
 namespace ts {
     export function transformESNext(context: TransformationContext) {
+        const {
+            startLexicalEnvironment,
+            endLexicalEnvironment,
+            hoistVariableDeclaration,
+        } = context;
+        let currentSourceFile: SourceFile;
         return transformSourceFile;
 
         function transformSourceFile(node: SourceFile) {
+            currentSourceFile = node;
             return visitEachChild(node, visitor, context);
         }
 
@@ -26,6 +33,23 @@ namespace ts {
             switch (node.kind) {
                 case SyntaxKind.ObjectLiteralExpression:
                     return visitObjectLiteralExpression(node as ObjectLiteralExpression);
+                case SyntaxKind.BinaryExpression:
+                    return visitBinaryExpression(node as BinaryExpression);
+                case SyntaxKind.VariableDeclaration:
+                    return visitVariableDeclaration(node as VariableDeclaration);
+                case SyntaxKind.ForOfStatement:
+                    return visitForOfStatement(node as ForOfStatement);
+                case SyntaxKind.ObjectBindingPattern:
+                case SyntaxKind.ArrayBindingPattern:
+                    return node;
+                case SyntaxKind.FunctionDeclaration:
+                    return visitFunctionDeclaration(node as FunctionDeclaration);
+                case SyntaxKind.FunctionExpression:
+                    return visitFunctionExpression(node as FunctionExpression);
+                case SyntaxKind.ArrowFunction:
+                    return visitArrowFunction(node as ArrowFunction);
+                case SyntaxKind.Parameter:
+                    return visitParameter(node as ParameterDeclaration);
                 default:
                     Debug.failBadSyntaxKind(node);
                     return visitEachChild(node, visitor, context);
@@ -76,5 +100,409 @@ namespace ts {
             }
             return createCall(createIdentifier("__assign"), undefined, objects);
         }
+
+        /**
+         * Visits a BinaryExpression that contains a destructuring assignment.
+         *
+         * @param node A BinaryExpression node.
+         */
+        function visitBinaryExpression(node: BinaryExpression): Expression {
+            if (isDestructuringAssignment(node) && node.left.transformFlags & TransformFlags.AssertESNext) {
+                return flattenDestructuringAssignment(context, node, /*needsDestructuringValue*/ true, hoistVariableDeclaration, visitor, /*transformRest*/ true);
+            }
+
+            return visitEachChild(node, visitor, context);
+        }
+
+        /**
+         * Visits a VariableDeclaration node with a binding pattern.
+         *
+         * @param node A VariableDeclaration node.
+         */
+        function visitVariableDeclaration(node: VariableDeclaration): VisitResult<VariableDeclaration> {
+            // If we are here it is because the name contains a binding pattern with a rest somewhere in it.
+            if (isBindingPattern(node.name) && node.name.transformFlags & TransformFlags.AssertESNext) {
+                const result = flattenVariableDestructuring(node, /*value*/ undefined, visitor, /*recordTempVariable*/ undefined, /*transformRest*/ true);
+                return result;
+            }
+
+            return visitEachChild(node, visitor, context);
+        }
+
+        /**
+         * Visits a ForOfStatement and converts it into a ES2015-compatible ForOfStatement.
+         *
+         * @param node A ForOfStatement.
+         */
+        function visitForOfStatement(node: ForOfStatement): VisitResult<Statement> {
+            // The following ESNext code:
+            //
+            //    for (let { x, y, ...rest } of expr) { }
+            //
+            // should be emitted as
+            //
+            //    for (var _a of expr) {
+            //        let { x, y } = _a, rest = __rest(_a, ["x", "y"]);
+            //    }
+            //
+            // where _a is a temp emitted to capture the RHS.
+            // When the left hand side is an expression instead of a let declaration,
+            // the `let` before the `{ x, y }` is not emitted.
+            // When the left hand side is a let/const, the v is renamed if there is
+            // another v in scope.
+            // Note that all assignments to the LHS are emitted in the body, including
+            // all destructuring.
+            // Note also that because an extra statement is needed to assign to the LHS,
+            // for-of bodies are always emitted as blocks.
+
+            // for (<init> of <expression>) <statement>
+            // where <init> is [let] variabledeclarationlist | expression
+            const initializer = node.initializer;
+            if (!isRestBindingPattern(initializer) && !isRestAssignment(initializer)) {
+                return visitEachChild(node, visitor, context);
+            }
+
+            const expression = visitNode(node.expression, visitor, isExpression);
+            const statements: Statement[] = [];
+            const rhsReference = createTempVariable(/*recordTempVariable*/ undefined);
+
+            // var { x, y } = _a, rest = __rest(_a, ["x", "y"]);
+            if (isVariableDeclarationList(initializer)) {
+                // This works whether the declaration is a var, let, or const.
+                // It will use rhsReference _a as the initializer.
+                const declarations = flattenVariableDestructuring(
+                    initializer.declarations[0],
+                    rhsReference,
+                    visitor,
+                    /*recordTempVariable*/ undefined,
+                    /*transformRest*/ true,
+                );
+
+                const declarationList = createVariableDeclarationList(declarations, /*location*/ initializer);
+                setOriginalNode(declarationList, initializer);
+
+                // Adjust the source map range for the first declaration to align with the old
+                // emitter.
+                const firstDeclaration = declarations[0];
+                const lastDeclaration = lastOrUndefined(declarations);
+                setSourceMapRange(declarationList, createRange(firstDeclaration.pos, lastDeclaration.end));
+
+                statements.push(
+                    createVariableStatement(
+                        /*modifiers*/ undefined,
+                        declarationList
+                    )
+                );
+            }
+            else {
+                // Initializer is an object literal destructuring assignment.
+                // Emit the flattened assignments from the object literal expression in the body
+                const assignment = createAssignment(initializer, rhsReference);
+                statements.push(
+                    createStatement(
+                        flattenDestructuringAssignment(
+                            context,
+                            assignment,
+                            /*needsValue*/ false,
+                            hoistVariableDeclaration,
+                            visitor,
+                            /*transformRest*/ true
+                        )
+                    )
+                );
+            }
+
+            let bodyLocation: TextRange;
+            let statementsLocation: TextRange;
+            const statement = visitNode(node.statement, visitor, isStatement);
+            if (isBlock(statement)) {
+                addRange(statements, statement.statements);
+                bodyLocation = statement;
+                statementsLocation = statement.statements;
+            }
+            else {
+                statements.push(statement);
+            }
+
+            // The old emitter does not emit source maps for the expression
+            setEmitFlags(expression, EmitFlags.NoSourceMap | getEmitFlags(expression));
+
+            // The old emitter does not emit source maps for the block.
+            // We add the location to preserve comments.
+            const body = createBlock(
+                createNodeArray(statements, /*location*/ statementsLocation),
+                /*location*/ bodyLocation
+            );
+
+            setEmitFlags(body, EmitFlags.NoSourceMap | EmitFlags.NoTokenSourceMaps);
+
+            const forStatement = createForOf(
+                createVariableDeclarationList([
+                    createVariableDeclaration(rhsReference, /*type*/ undefined, /*initializer*/ undefined, /*location*/ node.expression)
+                ], /*location*/ node.expression),
+                node.expression,
+                body,
+                /*location*/ node
+            );
+
+            // Disable trailing source maps for the OpenParenToken to align source map emit with the old emitter.
+            setEmitFlags(forStatement, EmitFlags.NoTokenTrailingSourceMaps);
+            return forStatement;
+        }
+
+        function isRestBindingPattern(initializer: ForInitializer) {
+            if (isVariableDeclarationList(initializer)) {
+                const declaration = firstOrUndefined(initializer.declarations);
+                return declaration && declaration.name &&
+                    declaration.name.kind === SyntaxKind.ObjectBindingPattern &&
+                    !!(declaration.name.transformFlags & TransformFlags.ContainsSpreadExpression);
+            }
+            return false;
+        }
+
+        function isRestAssignment(initializer: ForInitializer) {
+            return initializer.kind === SyntaxKind.ObjectLiteralExpression &&
+                initializer.transformFlags & TransformFlags.ContainsSpreadExpression;
+        }
+
+        function visitParameter(node: ParameterDeclaration): ParameterDeclaration {
+            if (isObjectRestParameter(node)) {
+                // Binding patterns are converted into a generated name and are
+                // evaluated inside the function body.
+                return setOriginalNode(
+                    createParameter(
+                        /*decorators*/ undefined,
+                        /*modifiers*/ undefined,
+                        /*dotDotDotToken*/ undefined,
+                        getGeneratedNameForNode(node),
+                        /*questionToken*/ undefined,
+                        /*type*/ undefined,
+                        node.initializer,
+                        /*location*/ node
+                    ),
+                    /*original*/ node
+                );
+            }
+            else {
+                return node;
+            }
+        }
+
+        function isObjectRestParameter(node: ParameterDeclaration) {
+            return node.name &&
+                node.name.kind === SyntaxKind.ObjectBindingPattern &&
+                !!(node.name.transformFlags & TransformFlags.ContainsSpreadExpression);
+        }
+
+        function visitFunctionDeclaration(node: FunctionDeclaration): FunctionDeclaration {
+            return setOriginalNode(
+                createFunctionDeclaration(
+                    /*decorators*/ undefined,
+                    node.modifiers,
+                    node.asteriskToken,
+                    node.name,
+                    /*typeParameters*/ undefined,
+                    visitNodes(node.parameters, visitor, isParameter),
+                    /*type*/ undefined,
+                    transformFunctionBody(node) as Block,
+                    /*location*/ node
+                ),
+                /*original*/ node);
+        }
+
+        function visitArrowFunction(node: ArrowFunction) {
+            const func = setOriginalNode(
+                createArrowFunction(
+                    /*modifiers*/ undefined,
+                    /*typeParameters*/ undefined,
+                    visitNodes(node.parameters, visitor, isParameter),
+                    /*type*/ undefined,
+                    node.equalsGreaterThanToken,
+                    transformFunctionBody(node),
+                    /*location*/ node
+                ),
+                /*original*/ node
+            );
+            setEmitFlags(func, EmitFlags.CapturesThis);
+            return func;
+        }
+
+        function visitFunctionExpression(node: FunctionExpression): Expression {
+            return setOriginalNode(
+                createFunctionExpression(
+                    /*modifiers*/ undefined,
+                    node.asteriskToken,
+                    name,
+                    /*typeParameters*/ undefined,
+                    visitNodes(node.parameters, visitor, isParameter),
+                    /*type*/ undefined,
+                    transformFunctionBody(node) as Block,
+                    /*location*/ node
+                ),
+                /*original*/ node
+            );
+        }
+
+        /**
+         * Transforms the body of a function-like node.
+         *
+         * @param node A function-like node.
+         */
+        function transformFunctionBody(node: FunctionLikeDeclaration): Block | Expression {
+            const hasRest = forEach(node.parameters, isObjectRestParameter);
+            if (!hasRest) {
+                return visitEachChild(node.body, visitor, context);
+            }
+
+            let multiLine = false; // indicates whether the block *must* be emitted as multiple lines
+            let singleLine = false; // indicates whether the block *may* be emitted as a single line
+            let statementsLocation: TextRange;
+            let closeBraceLocation: TextRange;
+
+            const statements: Statement[] = [];
+            const body = node.body;
+            let statementOffset: number;
+
+            startLexicalEnvironment();
+            if (isBlock(body)) {
+                // ensureUseStrict is false because no new prologue-directive should be added.
+                // addPrologueDirectives will simply put already-existing directives at the beginning of the target statement-array
+                statementOffset = addPrologueDirectives(statements, body.statements, /*ensureUseStrict*/ false, visitor);
+            }
+
+            addDefaultValueAssignmentsIfNeeded(statements, node);
+
+            // If we added any generated statements, this must be a multi-line block.
+            if (!multiLine && statements.length > 0) {
+                multiLine = true;
+            }
+
+            if (isBlock(body)) {
+                statementsLocation = body.statements;
+                addRange(statements, visitNodes(body.statements, visitor, isStatement, statementOffset));
+
+                // If the original body was a multi-line block, this must be a multi-line block.
+                if (!multiLine && body.multiLine) {
+                    multiLine = true;
+                }
+            }
+            else {
+                Debug.assert(node.kind === SyntaxKind.ArrowFunction);
+
+                // To align with the old emitter, we use a synthetic end position on the location
+                // for the statement list we synthesize when we down-level an arrow function with
+                // an expression function body. This prevents both comments and source maps from
+                // being emitted for the end position only.
+                statementsLocation = moveRangeEnd(body, -1);
+
+                const equalsGreaterThanToken = (<ArrowFunction>node).equalsGreaterThanToken;
+                if (!nodeIsSynthesized(equalsGreaterThanToken) && !nodeIsSynthesized(body)) {
+                    if (rangeEndIsOnSameLineAsRangeStart(equalsGreaterThanToken, body, currentSourceFile)) {
+                        singleLine = true;
+                    }
+                    else {
+                        multiLine = true;
+                    }
+                }
+
+                const expression = visitNode(body, visitor, isExpression);
+                const returnStatement = createReturn(expression, /*location*/ body);
+                setEmitFlags(returnStatement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoTrailingSourceMap | EmitFlags.NoTrailingComments);
+                statements.push(returnStatement);
+
+                // To align with the source map emit for the old emitter, we set a custom
+                // source map location for the close brace.
+                closeBraceLocation = body;
+            }
+
+            const lexicalEnvironment = endLexicalEnvironment();
+            addRange(statements, lexicalEnvironment);
+
+            // If we added any final generated statements, this must be a multi-line block
+            if (!multiLine && lexicalEnvironment && lexicalEnvironment.length) {
+                multiLine = true;
+            }
+
+            const block = createBlock(createNodeArray(statements, statementsLocation), node.body, multiLine);
+            if (!multiLine && singleLine) {
+                setEmitFlags(block, EmitFlags.SingleLine);
+            }
+
+            if (closeBraceLocation) {
+                setTokenSourceMapRange(block, SyntaxKind.CloseBraceToken, closeBraceLocation);
+            }
+
+            setOriginalNode(block, node.body);
+            return block;
+        }
+
+        function shouldAddDefaultValueAssignments(node: FunctionLikeDeclaration): boolean {
+            return !!(node.transformFlags & TransformFlags.ContainsDefaultValueAssignments);
+        }
+
+        /**
+         * Adds statements to the body of a function-like node if it contains parameters with
+         * binding patterns or initializers.
+         *
+         * @param statements The statements for the new function body.
+         * @param node A function-like node.
+         */
+        function addDefaultValueAssignmentsIfNeeded(statements: Statement[], node: FunctionLikeDeclaration): void {
+            if (!shouldAddDefaultValueAssignments(node)) {
+                return;
+            }
+
+            for (const parameter of node.parameters) {
+                // A rest parameter cannot have a binding pattern or an initializer,
+                // so let's just ignore it.
+                if (parameter.dotDotDotToken) {
+                    continue;
+                }
+
+                if (isBindingPattern(parameter.name)) {
+                    addDefaultValueAssignmentForBindingPattern(statements, parameter);
+                }
+            }
+        }
+
+        /**
+         * Adds statements to the body of a function-like node for parameters with binding patterns
+         *
+         * @param statements The statements for the new function body.
+         * @param parameter The parameter for the function.
+         */
+        function addDefaultValueAssignmentForBindingPattern(statements: Statement[], parameter: ParameterDeclaration): void {
+            const temp = getGeneratedNameForNode(parameter);
+
+            // In cases where a binding pattern is simply '[]' or '{}',
+            // we usually don't want to emit a var declaration; however, in the presence
+            // of an initializer, we must emit that expression to preserve side effects.
+            if ((parameter.name as BindingPattern).elements.length > 0) {
+                statements.push(
+                    setEmitFlags(
+                        createVariableStatement(
+                            /*modifiers*/ undefined,
+                            createVariableDeclarationList(
+                                flattenParameterDestructuring(parameter, temp, visitor, /*transformRest*/ true)
+                            )
+                        ),
+                        EmitFlags.CustomPrologue
+                    )
+                );
+            }
+            else if (parameter.initializer) {
+                statements.push(
+                    setEmitFlags(
+                        createStatement(
+                            createAssignment(
+                                temp,
+                                visitNode(parameter.initializer, visitor, isExpression)
+                            )
+                        ),
+                        EmitFlags.CustomPrologue
+                    )
+                );
+            }
+        }
     }
 }

From ac20b46f4fbd7a526bef4cf3fa20f36b079aee28 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 2 Nov 2016 14:56:58 -0700
Subject: [PATCH 154/224] Add rest tests

---
 .../conformance/types/rest/objectRest.ts      | 33 +++++++++++++++++++
 .../types/rest/objectRestAssignment.ts        |  7 ++++
 .../conformance/types/rest/objectRestForOf.ts | 14 ++++++++
 .../types/rest/objectRestNegative.ts          |  8 +++++
 .../types/rest/objectRestParameter.ts         |  8 +++++
 .../rest}/restElementMustBeLast.ts            |  0
 .../cases/fourslash/completionListForRest.ts  | 13 ++++++++
 tests/cases/fourslash/findAllRefsForRest.ts   | 12 +++++++
 tests/cases/fourslash/goToDefinitionRest.ts   | 12 +++++++
 tests/cases/fourslash/renameRest.ts           | 15 +++++++++
 10 files changed, 122 insertions(+)
 create mode 100644 tests/cases/conformance/types/rest/objectRest.ts
 create mode 100644 tests/cases/conformance/types/rest/objectRestAssignment.ts
 create mode 100644 tests/cases/conformance/types/rest/objectRestForOf.ts
 create mode 100644 tests/cases/conformance/types/rest/objectRestNegative.ts
 create mode 100644 tests/cases/conformance/types/rest/objectRestParameter.ts
 rename tests/cases/conformance/{es6/destructuring => types/rest}/restElementMustBeLast.ts (100%)
 create mode 100644 tests/cases/fourslash/completionListForRest.ts
 create mode 100644 tests/cases/fourslash/findAllRefsForRest.ts
 create mode 100644 tests/cases/fourslash/goToDefinitionRest.ts
 create mode 100644 tests/cases/fourslash/renameRest.ts

diff --git a/tests/cases/conformance/types/rest/objectRest.ts b/tests/cases/conformance/types/rest/objectRest.ts
new file mode 100644
index 0000000000000..f1a77b1c1299d
--- /dev/null
+++ b/tests/cases/conformance/types/rest/objectRest.ts
@@ -0,0 +1,33 @@
+// @target: es2015
+let o = { a: 1, b: 'no' }
+var { ...clone } = o;
+var { a, ...justB } = o;
+var { a, b: renamed, ...empty } = o;
+var { ['b']: renamed, ...justA } = o;
+var { 'b': renamed, ...justA } = o;
+var { b: { '0': n, '1': oooo }, ...justA } = o;
+
+let o2 = { c: 'terrible idea?', d: 'yes' };
+var { d: renamed, ...d } = o2;
+
+let nestedrest: { x: number, n1: { y: number, n2: { z: number, n3: { n4: number } } }, rest: number, restrest: number };
+var { x, n1: { y, n2: { z, n3: { ...nr } } }, ...restrest } = nestedrest;
+
+let complex: { x: { ka, ki }, y: number };
+var { x: { ka, ...nested }, y: other, ...rest } = complex;
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+var { x, ...fresh } = { x: 1, y: 2 };
+({ x, ...fresh } = { x: 1, y: 2 });
+
+class Removable {
+    private x: number;
+    protected y: number;
+    set z(value: number) { }
+    get both(): number { return 12 }
+    set both(value: number) { }
+    m() { }
+    removed: string;
+    remainder: string;
+}
+var removable = new Removable();
+var { removed, ...removableRest } = removable;
diff --git a/tests/cases/conformance/types/rest/objectRestAssignment.ts b/tests/cases/conformance/types/rest/objectRestAssignment.ts
new file mode 100644
index 0000000000000..19be53d29a3b3
--- /dev/null
+++ b/tests/cases/conformance/types/rest/objectRestAssignment.ts
@@ -0,0 +1,7 @@
+let x;
+let ka;
+let nested;
+let other;
+let rest;
+let complex: { x: { ka, ki }, y: number };
+({x: { ka, ...nested }, y: other, ...rest} = complex);
diff --git a/tests/cases/conformance/types/rest/objectRestForOf.ts b/tests/cases/conformance/types/rest/objectRestForOf.ts
new file mode 100644
index 0000000000000..4f675b1f15b91
--- /dev/null
+++ b/tests/cases/conformance/types/rest/objectRestForOf.ts
@@ -0,0 +1,14 @@
+// @target: es2015
+let array: { x: number, y: string }[];
+for (let { x, ...restOf } of array) {
+    [x, restOf];
+}
+let xx: number;
+let rrestOff: { y: string };
+for ({ x: xx, ...rrestOff } of array ) {
+    [xx, rrestOff];
+}
+for (const norest of array.map(a => ({ ...a, x: 'a string' }))) {
+    [norest.x, norest.y];
+    // x is now a string. who knows why.
+}
diff --git a/tests/cases/conformance/types/rest/objectRestNegative.ts b/tests/cases/conformance/types/rest/objectRestNegative.ts
new file mode 100644
index 0000000000000..7296f2d274e23
--- /dev/null
+++ b/tests/cases/conformance/types/rest/objectRestNegative.ts
@@ -0,0 +1,8 @@
+let o = { a: 1, b: 'no' };
+var { ...mustBeLast, a } = o;
+function stillMustBeLast({ ...mustBeLast, a }: { a: number, b: string }): void {
+}
+function generic<T extends { x, y }>(t: T) {
+    let { x, ...rest } = t;
+    return rest;
+}
diff --git a/tests/cases/conformance/types/rest/objectRestParameter.ts b/tests/cases/conformance/types/rest/objectRestParameter.ts
new file mode 100644
index 0000000000000..5b47442f047ab
--- /dev/null
+++ b/tests/cases/conformance/types/rest/objectRestParameter.ts
@@ -0,0 +1,8 @@
+// @target: es2015
+function cloneAgain({ a, ...clone }: { a: number, b: string }): void {
+}
+
+declare function suddenly(f: (a: { x: { z, ka }, y: string }) => void);
+suddenly(({ x: a, ...rest }) => rest.y);
+suddenly(({ x: { z = 12, ...nested }, ...rest } = { x: { z: 1, ka: 1 }, y: 'noo' }) => rest.y + nested.ka);
+
diff --git a/tests/cases/conformance/es6/destructuring/restElementMustBeLast.ts b/tests/cases/conformance/types/rest/restElementMustBeLast.ts
similarity index 100%
rename from tests/cases/conformance/es6/destructuring/restElementMustBeLast.ts
rename to tests/cases/conformance/types/rest/restElementMustBeLast.ts
diff --git a/tests/cases/fourslash/completionListForRest.ts b/tests/cases/fourslash/completionListForRest.ts
new file mode 100644
index 0000000000000..b880a90b3dff1
--- /dev/null
+++ b/tests/cases/fourslash/completionListForRest.ts
@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts'/>
+////interface Gen {
+////    x: number;
+////    parent: Gen;
+////    millenial: string;
+////}
+////let t: Gen;
+////var { x, ...rest } = t;
+////rest./*1*/x;
+goTo.marker('1');
+verify.memberListContains('parent', '(property) Gen.parent: Gen');
+verify.memberListContains('millenial', '(property) Gen.millenial: string');
+verify.memberListCount(2);
diff --git a/tests/cases/fourslash/findAllRefsForRest.ts b/tests/cases/fourslash/findAllRefsForRest.ts
new file mode 100644
index 0000000000000..c3a970e9e7359
--- /dev/null
+++ b/tests/cases/fourslash/findAllRefsForRest.ts
@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts'/>
+////interface Gen {
+////    x: number
+////    [|parent|]: Gen;
+////    millenial: string;
+////}
+////let t: Gen;
+////var { x, ...rest } = t;
+////rest.[|parent|];
+const ranges = test.ranges();
+verify.referencesOf(ranges[0], ranges);
+verify.referencesOf(ranges[1], ranges);
diff --git a/tests/cases/fourslash/goToDefinitionRest.ts b/tests/cases/fourslash/goToDefinitionRest.ts
new file mode 100644
index 0000000000000..1459b9ffa8845
--- /dev/null
+++ b/tests/cases/fourslash/goToDefinitionRest.ts
@@ -0,0 +1,12 @@
+
+/// <reference path='fourslash.ts'/>
+////interface Gen {
+////    x: number;
+////    /*1*/parent: Gen;
+////    millenial: string;
+////}
+////let t: Gen;
+////var { x, ...rest } = t;
+////rest./*2*/parent;
+const ranges = test.ranges();
+verify.goToDefinition('2', [ '1' ]);
diff --git a/tests/cases/fourslash/renameRest.ts b/tests/cases/fourslash/renameRest.ts
new file mode 100644
index 0000000000000..a5cc2c3868385
--- /dev/null
+++ b/tests/cases/fourslash/renameRest.ts
@@ -0,0 +1,15 @@
+/// <reference path='fourslash.ts'/>
+////interface Gen {
+////    x: number;
+////    [|parent|]: Gen;
+////    millenial: string;
+////}
+////let t: Gen;
+////var { x, ...rest } = t;
+////rest.[|parent|];
+const ranges = test.ranges();
+verify.assertHasRanges(ranges);
+goTo.position(ranges[0].start);
+verify.renameLocations(/*findInStrings*/ false, /*findInComments*/ false, ranges);
+goTo.position(ranges[1].start);
+verify.renameLocations(/*findInStrings*/ false, /*findInComments*/ false, ranges);

From 9d4ddb68c783de2c67384b408a788d3a2ec59bf8 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 2 Nov 2016 14:57:18 -0700
Subject: [PATCH 155/224] Update baselines

---
 tests/baselines/reference/objectRest.js       |   67 +
 tests/baselines/reference/objectRest.symbols  |  146 ++
 tests/baselines/reference/objectRest.types    |  170 ++
 .../reference/objectRestAssignment.js         |   25 +
 .../reference/objectRestAssignment.symbols    |   30 +
 .../reference/objectRestAssignment.types      |   36 +
 tests/baselines/reference/objectRestForOf.js  |   45 +
 .../reference/objectRestForOf.symbols         |   50 +
 .../baselines/reference/objectRestForOf.types |   61 +
 .../reference/objectRestNegative.errors.txt   |   21 +
 .../baselines/reference/objectRestNegative.js |   27 +
 .../reference/objectRestParameter.js          |   28 +
 .../reference/objectRestParameter.symbols     |   45 +
 .../reference/objectRestParameter.types       |   56 +
 .../restElementMustBeLast.errors.txt          |   10 +-
 ...ngForObjectBindingPatternDefaultValues2.js |   27 +-
 ...rObjectBindingPatternDefaultValues2.js.map |    2 +-
 ...BindingPatternDefaultValues2.sourcemap.txt | 1485 +++++++++--------
 18 files changed, 1582 insertions(+), 749 deletions(-)
 create mode 100644 tests/baselines/reference/objectRest.js
 create mode 100644 tests/baselines/reference/objectRest.symbols
 create mode 100644 tests/baselines/reference/objectRest.types
 create mode 100644 tests/baselines/reference/objectRestAssignment.js
 create mode 100644 tests/baselines/reference/objectRestAssignment.symbols
 create mode 100644 tests/baselines/reference/objectRestAssignment.types
 create mode 100644 tests/baselines/reference/objectRestForOf.js
 create mode 100644 tests/baselines/reference/objectRestForOf.symbols
 create mode 100644 tests/baselines/reference/objectRestForOf.types
 create mode 100644 tests/baselines/reference/objectRestNegative.errors.txt
 create mode 100644 tests/baselines/reference/objectRestNegative.js
 create mode 100644 tests/baselines/reference/objectRestParameter.js
 create mode 100644 tests/baselines/reference/objectRestParameter.symbols
 create mode 100644 tests/baselines/reference/objectRestParameter.types

diff --git a/tests/baselines/reference/objectRest.js b/tests/baselines/reference/objectRest.js
new file mode 100644
index 0000000000000..a295ff7b9f1a2
--- /dev/null
+++ b/tests/baselines/reference/objectRest.js
@@ -0,0 +1,67 @@
+//// [objectRest.ts]
+let o = { a: 1, b: 'no' }
+var { ...clone } = o;
+var { a, ...justB } = o;
+var { a, b: renamed, ...empty } = o;
+var { ['b']: renamed, ...justA } = o;
+var { 'b': renamed, ...justA } = o;
+var { b: { '0': n, '1': oooo }, ...justA } = o;
+
+let o2 = { c: 'terrible idea?', d: 'yes' };
+var { d: renamed, ...d } = o2;
+
+let nestedrest: { x: number, n1: { y: number, n2: { z: number, n3: { n4: number } } }, rest: number, restrest: number };
+var { x, n1: { y, n2: { z, n3: { ...nr } } }, ...restrest } = nestedrest;
+
+let complex: { x: { ka, ki }, y: number };
+var { x: { ka, ...nested }, y: other, ...rest } = complex;
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+var { x, ...fresh } = { x: 1, y: 2 };
+({ x, ...fresh } = { x: 1, y: 2 });
+
+class Removable {
+    private x: number;
+    protected y: number;
+    set z(value: number) { }
+    get both(): number { return 12 }
+    set both(value: number) { }
+    m() { }
+    removed: string;
+    remainder: string;
+}
+var removable = new Removable();
+var { removed, ...removableRest } = removable;
+
+
+//// [objectRest.js]
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
+        t[p] = s[p];
+    return t;
+};
+let o = { a: 1, b: 'no' };
+var clone = __rest(o, []);
+var { a } = o, justB = __rest(o, ["a"]);
+var { a, b: renamed } = o, empty = __rest(o, ["a", "b"]);
+var { ['b']: renamed } = o, justA = __rest(o, ["b"]);
+var { 'b': renamed } = o, justA = __rest(o, ["b"]);
+var { b: { '0': n, '1': oooo } } = o, justA = __rest(o, ["b"]);
+let o2 = { c: 'terrible idea?', d: 'yes' };
+var { d: renamed } = o2, d = __rest(o2, ["d"]);
+let nestedrest;
+var { x } = nestedrest, _a = nestedrest.n1, { y } = _a, _b = _a.n2, { z } = _b, nr = __rest(_b.n3, []), restrest = __rest(nestedrest, ["x", "n1"]);
+let complex;
+var _c = complex.x, { ka } = _c, nested = __rest(_c, ["ka"]), { y: other } = complex, rest = __rest(complex, ["x", "y"]);
+(_d = complex.x, { ka } = _d, nested = __rest(_d, ["ka"]), { y: other } = complex, rest = __rest(complex, ["x", "y"]), complex);
+var _e = { x: 1, y: 2 }, { x } = _e, fresh = __rest(_e, ["x"]);
+(_f = { x: 1, y: 2 }, { x } = _f, fresh = __rest(_f, ["x"]), _f);
+class Removable {
+    set z(value) { }
+    get both() { return 12; }
+    set both(value) { }
+    m() { }
+}
+var removable = new Removable();
+var { removed } = removable, removableRest = __rest(removable, ["removed"]);
+var _d, _f;
diff --git a/tests/baselines/reference/objectRest.symbols b/tests/baselines/reference/objectRest.symbols
new file mode 100644
index 0000000000000..427656248ee19
--- /dev/null
+++ b/tests/baselines/reference/objectRest.symbols
@@ -0,0 +1,146 @@
+=== tests/cases/conformance/types/rest/objectRest.ts ===
+let o = { a: 1, b: 'no' }
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+>a : Symbol(a, Decl(objectRest.ts, 0, 9))
+>b : Symbol(b, Decl(objectRest.ts, 0, 15))
+
+var { ...clone } = o;
+>clone : Symbol(clone, Decl(objectRest.ts, 1, 5))
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+
+var { a, ...justB } = o;
+>a : Symbol(a, Decl(objectRest.ts, 2, 5), Decl(objectRest.ts, 3, 5))
+>justB : Symbol(justB, Decl(objectRest.ts, 2, 8))
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+
+var { a, b: renamed, ...empty } = o;
+>a : Symbol(a, Decl(objectRest.ts, 2, 5), Decl(objectRest.ts, 3, 5))
+>b : Symbol(b, Decl(objectRest.ts, 0, 15))
+>renamed : Symbol(renamed, Decl(objectRest.ts, 3, 8), Decl(objectRest.ts, 4, 5), Decl(objectRest.ts, 5, 5), Decl(objectRest.ts, 9, 5))
+>empty : Symbol(empty, Decl(objectRest.ts, 3, 20))
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+
+var { ['b']: renamed, ...justA } = o;
+>'b' : Symbol(renamed, Decl(objectRest.ts, 3, 8), Decl(objectRest.ts, 4, 5), Decl(objectRest.ts, 5, 5), Decl(objectRest.ts, 9, 5))
+>renamed : Symbol(renamed, Decl(objectRest.ts, 3, 8), Decl(objectRest.ts, 4, 5), Decl(objectRest.ts, 5, 5), Decl(objectRest.ts, 9, 5))
+>justA : Symbol(justA, Decl(objectRest.ts, 4, 21), Decl(objectRest.ts, 5, 19), Decl(objectRest.ts, 6, 31))
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+
+var { 'b': renamed, ...justA } = o;
+>renamed : Symbol(renamed, Decl(objectRest.ts, 3, 8), Decl(objectRest.ts, 4, 5), Decl(objectRest.ts, 5, 5), Decl(objectRest.ts, 9, 5))
+>justA : Symbol(justA, Decl(objectRest.ts, 4, 21), Decl(objectRest.ts, 5, 19), Decl(objectRest.ts, 6, 31))
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+
+var { b: { '0': n, '1': oooo }, ...justA } = o;
+>b : Symbol(b, Decl(objectRest.ts, 0, 15))
+>n : Symbol(n, Decl(objectRest.ts, 6, 10))
+>oooo : Symbol(oooo, Decl(objectRest.ts, 6, 18))
+>justA : Symbol(justA, Decl(objectRest.ts, 4, 21), Decl(objectRest.ts, 5, 19), Decl(objectRest.ts, 6, 31))
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+
+let o2 = { c: 'terrible idea?', d: 'yes' };
+>o2 : Symbol(o2, Decl(objectRest.ts, 8, 3))
+>c : Symbol(c, Decl(objectRest.ts, 8, 10))
+>d : Symbol(d, Decl(objectRest.ts, 8, 31))
+
+var { d: renamed, ...d } = o2;
+>d : Symbol(d, Decl(objectRest.ts, 8, 31))
+>renamed : Symbol(renamed, Decl(objectRest.ts, 3, 8), Decl(objectRest.ts, 4, 5), Decl(objectRest.ts, 5, 5), Decl(objectRest.ts, 9, 5))
+>d : Symbol(d, Decl(objectRest.ts, 9, 17))
+>o2 : Symbol(o2, Decl(objectRest.ts, 8, 3))
+
+let nestedrest: { x: number, n1: { y: number, n2: { z: number, n3: { n4: number } } }, rest: number, restrest: number };
+>nestedrest : Symbol(nestedrest, Decl(objectRest.ts, 11, 3))
+>x : Symbol(x, Decl(objectRest.ts, 11, 17))
+>n1 : Symbol(n1, Decl(objectRest.ts, 11, 28))
+>y : Symbol(y, Decl(objectRest.ts, 11, 34))
+>n2 : Symbol(n2, Decl(objectRest.ts, 11, 45))
+>z : Symbol(z, Decl(objectRest.ts, 11, 51))
+>n3 : Symbol(n3, Decl(objectRest.ts, 11, 62))
+>n4 : Symbol(n4, Decl(objectRest.ts, 11, 68))
+>rest : Symbol(rest, Decl(objectRest.ts, 11, 86))
+>restrest : Symbol(restrest, Decl(objectRest.ts, 11, 100))
+
+var { x, n1: { y, n2: { z, n3: { ...nr } } }, ...restrest } = nestedrest;
+>x : Symbol(x, Decl(objectRest.ts, 12, 5), Decl(objectRest.ts, 17, 5))
+>n1 : Symbol(n1, Decl(objectRest.ts, 11, 28))
+>y : Symbol(y, Decl(objectRest.ts, 12, 14))
+>n2 : Symbol(n2, Decl(objectRest.ts, 11, 45))
+>z : Symbol(z, Decl(objectRest.ts, 12, 23))
+>n3 : Symbol(n3, Decl(objectRest.ts, 11, 62))
+>nr : Symbol(nr, Decl(objectRest.ts, 12, 32))
+>restrest : Symbol(restrest, Decl(objectRest.ts, 12, 45))
+>nestedrest : Symbol(nestedrest, Decl(objectRest.ts, 11, 3))
+
+let complex: { x: { ka, ki }, y: number };
+>complex : Symbol(complex, Decl(objectRest.ts, 14, 3))
+>x : Symbol(x, Decl(objectRest.ts, 14, 14))
+>ka : Symbol(ka, Decl(objectRest.ts, 14, 19))
+>ki : Symbol(ki, Decl(objectRest.ts, 14, 23))
+>y : Symbol(y, Decl(objectRest.ts, 14, 29))
+
+var { x: { ka, ...nested }, y: other, ...rest } = complex;
+>x : Symbol(x, Decl(objectRest.ts, 14, 14))
+>ka : Symbol(ka, Decl(objectRest.ts, 15, 10))
+>nested : Symbol(nested, Decl(objectRest.ts, 15, 14))
+>y : Symbol(y, Decl(objectRest.ts, 14, 29))
+>other : Symbol(other, Decl(objectRest.ts, 15, 27))
+>rest : Symbol(rest, Decl(objectRest.ts, 15, 37))
+>complex : Symbol(complex, Decl(objectRest.ts, 14, 3))
+
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+>x : Symbol(x, Decl(objectRest.ts, 16, 2))
+>ka : Symbol(ka, Decl(objectRest.ts, 16, 6))
+>y : Symbol(y, Decl(objectRest.ts, 16, 23))
+>other : Symbol(other, Decl(objectRest.ts, 15, 27))
+>complex : Symbol(complex, Decl(objectRest.ts, 14, 3))
+
+var { x, ...fresh } = { x: 1, y: 2 };
+>x : Symbol(x, Decl(objectRest.ts, 12, 5), Decl(objectRest.ts, 17, 5))
+>fresh : Symbol(fresh, Decl(objectRest.ts, 17, 8))
+>x : Symbol(x, Decl(objectRest.ts, 17, 23))
+>y : Symbol(y, Decl(objectRest.ts, 17, 29))
+
+({ x, ...fresh } = { x: 1, y: 2 });
+>x : Symbol(x, Decl(objectRest.ts, 18, 2))
+>x : Symbol(x, Decl(objectRest.ts, 18, 20))
+>y : Symbol(y, Decl(objectRest.ts, 18, 26))
+
+class Removable {
+>Removable : Symbol(Removable, Decl(objectRest.ts, 18, 35))
+
+    private x: number;
+>x : Symbol(Removable.x, Decl(objectRest.ts, 20, 17))
+
+    protected y: number;
+>y : Symbol(Removable.y, Decl(objectRest.ts, 21, 22))
+
+    set z(value: number) { }
+>z : Symbol(Removable.z, Decl(objectRest.ts, 22, 24))
+>value : Symbol(value, Decl(objectRest.ts, 23, 10))
+
+    get both(): number { return 12 }
+>both : Symbol(Removable.both, Decl(objectRest.ts, 23, 28), Decl(objectRest.ts, 24, 36))
+
+    set both(value: number) { }
+>both : Symbol(Removable.both, Decl(objectRest.ts, 23, 28), Decl(objectRest.ts, 24, 36))
+>value : Symbol(value, Decl(objectRest.ts, 25, 13))
+
+    m() { }
+>m : Symbol(Removable.m, Decl(objectRest.ts, 25, 31))
+
+    removed: string;
+>removed : Symbol(Removable.removed, Decl(objectRest.ts, 26, 11))
+
+    remainder: string;
+>remainder : Symbol(Removable.remainder, Decl(objectRest.ts, 27, 20))
+}
+var removable = new Removable();
+>removable : Symbol(removable, Decl(objectRest.ts, 30, 3))
+>Removable : Symbol(Removable, Decl(objectRest.ts, 18, 35))
+
+var { removed, ...removableRest } = removable;
+>removed : Symbol(removed, Decl(objectRest.ts, 31, 5))
+>removableRest : Symbol(removableRest, Decl(objectRest.ts, 31, 14))
+>removable : Symbol(removable, Decl(objectRest.ts, 30, 3))
+
diff --git a/tests/baselines/reference/objectRest.types b/tests/baselines/reference/objectRest.types
new file mode 100644
index 0000000000000..95e378359c8ba
--- /dev/null
+++ b/tests/baselines/reference/objectRest.types
@@ -0,0 +1,170 @@
+=== tests/cases/conformance/types/rest/objectRest.ts ===
+let o = { a: 1, b: 'no' }
+>o : { a: number; b: string; }
+>{ a: 1, b: 'no' } : { a: number; b: string; }
+>a : number
+>1 : 1
+>b : string
+>'no' : "no"
+
+var { ...clone } = o;
+>clone : { a: number; b: string; }
+>o : { a: number; b: string; }
+
+var { a, ...justB } = o;
+>a : number
+>justB : { b: string; }
+>o : { a: number; b: string; }
+
+var { a, b: renamed, ...empty } = o;
+>a : number
+>b : any
+>renamed : string
+>empty : {}
+>o : { a: number; b: string; }
+
+var { ['b']: renamed, ...justA } = o;
+>'b' : "b"
+>renamed : string
+>justA : { a: number; }
+>o : { a: number; b: string; }
+
+var { 'b': renamed, ...justA } = o;
+>renamed : string
+>justA : { a: number; }
+>o : { a: number; b: string; }
+
+var { b: { '0': n, '1': oooo }, ...justA } = o;
+>b : any
+>n : string
+>oooo : string
+>justA : { a: number; }
+>o : { a: number; b: string; }
+
+let o2 = { c: 'terrible idea?', d: 'yes' };
+>o2 : { c: string; d: string; }
+>{ c: 'terrible idea?', d: 'yes' } : { c: string; d: string; }
+>c : string
+>'terrible idea?' : "terrible idea?"
+>d : string
+>'yes' : "yes"
+
+var { d: renamed, ...d } = o2;
+>d : any
+>renamed : string
+>d : { c: string; }
+>o2 : { c: string; d: string; }
+
+let nestedrest: { x: number, n1: { y: number, n2: { z: number, n3: { n4: number } } }, rest: number, restrest: number };
+>nestedrest : { x: number; n1: { y: number; n2: { z: number; n3: { n4: number; }; }; }; rest: number; restrest: number; }
+>x : number
+>n1 : { y: number; n2: { z: number; n3: { n4: number; }; }; }
+>y : number
+>n2 : { z: number; n3: { n4: number; }; }
+>z : number
+>n3 : { n4: number; }
+>n4 : number
+>rest : number
+>restrest : number
+
+var { x, n1: { y, n2: { z, n3: { ...nr } } }, ...restrest } = nestedrest;
+>x : number
+>n1 : any
+>y : number
+>n2 : any
+>z : number
+>n3 : any
+>nr : { n4: number; }
+>restrest : { rest: number; restrest: number; }
+>nestedrest : { x: number; n1: { y: number; n2: { z: number; n3: { n4: number; }; }; }; rest: number; restrest: number; }
+
+let complex: { x: { ka, ki }, y: number };
+>complex : { x: { ka: any; ki: any; }; y: number; }
+>x : { ka: any; ki: any; }
+>ka : any
+>ki : any
+>y : number
+
+var { x: { ka, ...nested }, y: other, ...rest } = complex;
+>x : any
+>ka : any
+>nested : { ki: any; }
+>y : any
+>other : number
+>rest : {}
+>complex : { x: { ka: any; ki: any; }; y: number; }
+
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+>({x: { ka, ...nested }, y: other, ...rest} = complex) : { x: { ka: any; ki: any; }; y: number; }
+>{x: { ka, ...nested }, y: other, ...rest} = complex : { x: { ka: any; ki: any; }; y: number; }
+>{x: { ka, ...nested }, y: other, ...rest} : { x: { ki: any; ka: any; }; y: number; }
+>x : { ki: any; ka: any; }
+>{ ka, ...nested } : { ki: any; ka: any; }
+>ka : any
+>nested : any
+>y : number
+>other : number
+>rest : any
+>complex : { x: { ka: any; ki: any; }; y: number; }
+
+var { x, ...fresh } = { x: 1, y: 2 };
+>x : number
+>fresh : { y: number; }
+>{ x: 1, y: 2 } : { x: number; y: number; }
+>x : number
+>1 : 1
+>y : number
+>2 : 2
+
+({ x, ...fresh } = { x: 1, y: 2 });
+>({ x, ...fresh } = { x: 1, y: 2 }) : { x: number; y: number; }
+>{ x, ...fresh } = { x: 1, y: 2 } : { x: number; y: number; }
+>{ x, ...fresh } : { y: number; x: number; }
+>x : number
+>fresh : any
+>{ x: 1, y: 2 } : { x: number; y: number; }
+>x : number
+>1 : 1
+>y : number
+>2 : 2
+
+class Removable {
+>Removable : Removable
+
+    private x: number;
+>x : number
+
+    protected y: number;
+>y : number
+
+    set z(value: number) { }
+>z : number
+>value : number
+
+    get both(): number { return 12 }
+>both : number
+>12 : 12
+
+    set both(value: number) { }
+>both : number
+>value : number
+
+    m() { }
+>m : () => void
+
+    removed: string;
+>removed : string
+
+    remainder: string;
+>remainder : string
+}
+var removable = new Removable();
+>removable : Removable
+>new Removable() : Removable
+>Removable : typeof Removable
+
+var { removed, ...removableRest } = removable;
+>removed : string
+>removableRest : { both: number; remainder: string; }
+>removable : Removable
+
diff --git a/tests/baselines/reference/objectRestAssignment.js b/tests/baselines/reference/objectRestAssignment.js
new file mode 100644
index 0000000000000..7ecd54c51527a
--- /dev/null
+++ b/tests/baselines/reference/objectRestAssignment.js
@@ -0,0 +1,25 @@
+//// [objectRestAssignment.ts]
+let x;
+let ka;
+let nested;
+let other;
+let rest;
+let complex: { x: { ka, ki }, y: number };
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+
+
+//// [objectRestAssignment.js]
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
+        t[p] = s[p];
+    return t;
+};
+var x;
+var ka;
+var nested;
+var other;
+var rest;
+var complex;
+(_a = complex.x, (ka = _a.ka, _a), nested = __rest(_a, ["ka"]), (other = complex.y, complex), rest = __rest(complex, ["x", "y"]), complex);
+var _a;
diff --git a/tests/baselines/reference/objectRestAssignment.symbols b/tests/baselines/reference/objectRestAssignment.symbols
new file mode 100644
index 0000000000000..3c54290b5954b
--- /dev/null
+++ b/tests/baselines/reference/objectRestAssignment.symbols
@@ -0,0 +1,30 @@
+=== tests/cases/conformance/types/rest/objectRestAssignment.ts ===
+let x;
+>x : Symbol(x, Decl(objectRestAssignment.ts, 0, 3))
+
+let ka;
+>ka : Symbol(ka, Decl(objectRestAssignment.ts, 1, 3))
+
+let nested;
+>nested : Symbol(nested, Decl(objectRestAssignment.ts, 2, 3))
+
+let other;
+>other : Symbol(other, Decl(objectRestAssignment.ts, 3, 3))
+
+let rest;
+>rest : Symbol(rest, Decl(objectRestAssignment.ts, 4, 3))
+
+let complex: { x: { ka, ki }, y: number };
+>complex : Symbol(complex, Decl(objectRestAssignment.ts, 5, 3))
+>x : Symbol(x, Decl(objectRestAssignment.ts, 5, 14))
+>ka : Symbol(ka, Decl(objectRestAssignment.ts, 5, 19))
+>ki : Symbol(ki, Decl(objectRestAssignment.ts, 5, 23))
+>y : Symbol(y, Decl(objectRestAssignment.ts, 5, 29))
+
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+>x : Symbol(x, Decl(objectRestAssignment.ts, 6, 2))
+>ka : Symbol(ka, Decl(objectRestAssignment.ts, 6, 6))
+>y : Symbol(y, Decl(objectRestAssignment.ts, 6, 23))
+>other : Symbol(other, Decl(objectRestAssignment.ts, 3, 3))
+>complex : Symbol(complex, Decl(objectRestAssignment.ts, 5, 3))
+
diff --git a/tests/baselines/reference/objectRestAssignment.types b/tests/baselines/reference/objectRestAssignment.types
new file mode 100644
index 0000000000000..5af3e5872b95e
--- /dev/null
+++ b/tests/baselines/reference/objectRestAssignment.types
@@ -0,0 +1,36 @@
+=== tests/cases/conformance/types/rest/objectRestAssignment.ts ===
+let x;
+>x : any
+
+let ka;
+>ka : any
+
+let nested;
+>nested : any
+
+let other;
+>other : any
+
+let rest;
+>rest : any
+
+let complex: { x: { ka, ki }, y: number };
+>complex : { x: { ka: any; ki: any; }; y: number; }
+>x : { ka: any; ki: any; }
+>ka : any
+>ki : any
+>y : number
+
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+>({x: { ka, ...nested }, y: other, ...rest} = complex) : { x: { ka: any; ki: any; }; y: number; }
+>{x: { ka, ...nested }, y: other, ...rest} = complex : { x: { ka: any; ki: any; }; y: number; }
+>{x: { ka, ...nested }, y: other, ...rest} : { x: { ka: any; }; y: any; }
+>x : { ka: any; }
+>{ ka, ...nested } : { ka: any; }
+>ka : any
+>nested : any
+>y : any
+>other : any
+>rest : any
+>complex : { x: { ka: any; ki: any; }; y: number; }
+
diff --git a/tests/baselines/reference/objectRestForOf.js b/tests/baselines/reference/objectRestForOf.js
new file mode 100644
index 0000000000000..0a6e2dc40ed34
--- /dev/null
+++ b/tests/baselines/reference/objectRestForOf.js
@@ -0,0 +1,45 @@
+//// [objectRestForOf.ts]
+let array: { x: number, y: string }[];
+for (let { x, ...restOf } of array) {
+    [x, restOf];
+}
+let xx: number;
+let rrestOff: { y: string };
+for ({ x: xx, ...rrestOff } of array ) {
+    [xx, rrestOff];
+}
+for (const norest of array.map(a => ({ ...a, x: 'a string' }))) {
+    [norest.x, norest.y];
+    // x is now a string. who knows why.
+}
+
+
+//// [objectRestForOf.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
+        t[p] = s[p];
+    return t;
+};
+let array;
+for (var _a of array) {
+    var { x } = _a, restOf = __rest(_a, ["x"]);
+    [x, restOf];
+}
+let xx;
+let rrestOff;
+for (var _b of array) {
+    ({ x: xx } = _b, rrestOff = __rest(_b, ["x"]));
+    [xx, rrestOff];
+}
+for (const norest of array.map(a => (__assign({}, a, { x: 'a string' })))) {
+    [norest.x, norest.y];
+}
diff --git a/tests/baselines/reference/objectRestForOf.symbols b/tests/baselines/reference/objectRestForOf.symbols
new file mode 100644
index 0000000000000..ec0ccde740d5b
--- /dev/null
+++ b/tests/baselines/reference/objectRestForOf.symbols
@@ -0,0 +1,50 @@
+=== tests/cases/conformance/types/rest/objectRestForOf.ts ===
+let array: { x: number, y: string }[];
+>array : Symbol(array, Decl(objectRestForOf.ts, 0, 3))
+>x : Symbol(x, Decl(objectRestForOf.ts, 0, 12))
+>y : Symbol(y, Decl(objectRestForOf.ts, 0, 23))
+
+for (let { x, ...restOf } of array) {
+>x : Symbol(x, Decl(objectRestForOf.ts, 1, 10))
+>restOf : Symbol(restOf, Decl(objectRestForOf.ts, 1, 13))
+>array : Symbol(array, Decl(objectRestForOf.ts, 0, 3))
+
+    [x, restOf];
+>x : Symbol(x, Decl(objectRestForOf.ts, 1, 10))
+>restOf : Symbol(restOf, Decl(objectRestForOf.ts, 1, 13))
+}
+let xx: number;
+>xx : Symbol(xx, Decl(objectRestForOf.ts, 4, 3))
+
+let rrestOff: { y: string };
+>rrestOff : Symbol(rrestOff, Decl(objectRestForOf.ts, 5, 3))
+>y : Symbol(y, Decl(objectRestForOf.ts, 5, 15))
+
+for ({ x: xx, ...rrestOff } of array ) {
+>x : Symbol(x, Decl(objectRestForOf.ts, 6, 6))
+>xx : Symbol(xx, Decl(objectRestForOf.ts, 4, 3))
+>array : Symbol(array, Decl(objectRestForOf.ts, 0, 3))
+
+    [xx, rrestOff];
+>xx : Symbol(xx, Decl(objectRestForOf.ts, 4, 3))
+>rrestOff : Symbol(rrestOff, Decl(objectRestForOf.ts, 5, 3))
+}
+for (const norest of array.map(a => ({ ...a, x: 'a string' }))) {
+>norest : Symbol(norest, Decl(objectRestForOf.ts, 9, 10))
+>array.map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>array : Symbol(array, Decl(objectRestForOf.ts, 0, 3))
+>map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>a : Symbol(a, Decl(objectRestForOf.ts, 9, 31))
+>x : Symbol(x, Decl(objectRestForOf.ts, 9, 44))
+
+    [norest.x, norest.y];
+>norest.x : Symbol(x, Decl(objectRestForOf.ts, 9, 44))
+>norest : Symbol(norest, Decl(objectRestForOf.ts, 9, 10))
+>x : Symbol(x, Decl(objectRestForOf.ts, 9, 44))
+>norest.y : Symbol(y, Decl(objectRestForOf.ts, 0, 23))
+>norest : Symbol(norest, Decl(objectRestForOf.ts, 9, 10))
+>y : Symbol(y, Decl(objectRestForOf.ts, 0, 23))
+
+    // x is now a string. who knows why.
+}
+
diff --git a/tests/baselines/reference/objectRestForOf.types b/tests/baselines/reference/objectRestForOf.types
new file mode 100644
index 0000000000000..e8c3b4a82abf1
--- /dev/null
+++ b/tests/baselines/reference/objectRestForOf.types
@@ -0,0 +1,61 @@
+=== tests/cases/conformance/types/rest/objectRestForOf.ts ===
+let array: { x: number, y: string }[];
+>array : { x: number; y: string; }[]
+>x : number
+>y : string
+
+for (let { x, ...restOf } of array) {
+>x : number
+>restOf : { y: string; }
+>array : { x: number; y: string; }[]
+
+    [x, restOf];
+>[x, restOf] : (number | { y: string; })[]
+>x : number
+>restOf : { y: string; }
+}
+let xx: number;
+>xx : number
+
+let rrestOff: { y: string };
+>rrestOff : { y: string; }
+>y : string
+
+for ({ x: xx, ...rrestOff } of array ) {
+>{ x: xx, ...rrestOff } : { y: string; x: number; }
+>x : { x: number; y: string; }
+>xx : number
+>rrestOff : any
+>array : { x: number; y: string; }[]
+
+    [xx, rrestOff];
+>[xx, rrestOff] : (number | { y: string; })[]
+>xx : number
+>rrestOff : { y: string; }
+}
+for (const norest of array.map(a => ({ ...a, x: 'a string' }))) {
+>norest : { x: string; y: string; }
+>array.map(a => ({ ...a, x: 'a string' })) : { x: string; y: string; }[]
+>array.map : { <U>(this: [{ x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U, U, U, U]; <U>(this: [{ x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U, U, U]; <U>(this: [{ x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U, U]; <U>(this: [{ x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U]; <U>(callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): U[]; }
+>array : { x: number; y: string; }[]
+>map : { <U>(this: [{ x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U, U, U, U]; <U>(this: [{ x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U, U, U]; <U>(this: [{ x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U, U]; <U>(this: [{ x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U]; <U>(callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): U[]; }
+>a => ({ ...a, x: 'a string' }) : (a: { x: number; y: string; }) => { x: string; y: string; }
+>a : { x: number; y: string; }
+>({ ...a, x: 'a string' }) : { x: string; y: string; }
+>{ ...a, x: 'a string' } : { x: string; y: string; }
+>a : any
+>x : string
+>'a string' : "a string"
+
+    [norest.x, norest.y];
+>[norest.x, norest.y] : string[]
+>norest.x : string
+>norest : { x: string; y: string; }
+>x : string
+>norest.y : string
+>norest : { x: string; y: string; }
+>y : string
+
+    // x is now a string. who knows why.
+}
+
diff --git a/tests/baselines/reference/objectRestNegative.errors.txt b/tests/baselines/reference/objectRestNegative.errors.txt
new file mode 100644
index 0000000000000..1874570da7c9f
--- /dev/null
+++ b/tests/baselines/reference/objectRestNegative.errors.txt
@@ -0,0 +1,21 @@
+tests/cases/conformance/types/rest/objectRestNegative.ts(2,10): error TS2462: A rest element must be last in a destructuring pattern
+tests/cases/conformance/types/rest/objectRestNegative.ts(3,31): error TS2462: A rest element must be last in a destructuring pattern
+tests/cases/conformance/types/rest/objectRestNegative.ts(6,17): error TS2700: Rest types may only be created from object types.
+
+
+==== tests/cases/conformance/types/rest/objectRestNegative.ts (3 errors) ====
+    let o = { a: 1, b: 'no' };
+    var { ...mustBeLast, a } = o;
+             ~~~~~~~~~~
+!!! error TS2462: A rest element must be last in a destructuring pattern
+    function stillMustBeLast({ ...mustBeLast, a }: { a: number, b: string }): void {
+                                  ~~~~~~~~~~
+!!! error TS2462: A rest element must be last in a destructuring pattern
+    }
+    function generic<T extends { x, y }>(t: T) {
+        let { x, ...rest } = t;
+                    ~~~~
+!!! error TS2700: Rest types may only be created from object types.
+        return rest;
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/objectRestNegative.js b/tests/baselines/reference/objectRestNegative.js
new file mode 100644
index 0000000000000..b3b49740762aa
--- /dev/null
+++ b/tests/baselines/reference/objectRestNegative.js
@@ -0,0 +1,27 @@
+//// [objectRestNegative.ts]
+let o = { a: 1, b: 'no' };
+var { ...mustBeLast, a } = o;
+function stillMustBeLast({ ...mustBeLast, a }: { a: number, b: string }): void {
+}
+function generic<T extends { x, y }>(t: T) {
+    let { x, ...rest } = t;
+    return rest;
+}
+
+
+//// [objectRestNegative.js]
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
+        t[p] = s[p];
+    return t;
+};
+var o = { a: 1, b: 'no' };
+var mustBeLast = o.mustBeLast, a = o.a;
+function stillMustBeLast(_a) {
+    var mustBeLast = _a.mustBeLast, a = _a.a;
+}
+function generic(t) {
+    var x = t.x, rest = __rest(t, ["x"]);
+    return rest;
+}
diff --git a/tests/baselines/reference/objectRestParameter.js b/tests/baselines/reference/objectRestParameter.js
new file mode 100644
index 0000000000000..49434f24eece7
--- /dev/null
+++ b/tests/baselines/reference/objectRestParameter.js
@@ -0,0 +1,28 @@
+//// [objectRestParameter.ts]
+function cloneAgain({ a, ...clone }: { a: number, b: string }): void {
+}
+
+declare function suddenly(f: (a: { x: { z, ka }, y: string }) => void);
+suddenly(({ x: a, ...rest }) => rest.y);
+suddenly(({ x: { z = 12, ...nested }, ...rest } = { x: { z: 1, ka: 1 }, y: 'noo' }) => rest.y + nested.ka);
+
+
+
+//// [objectRestParameter.js]
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
+        t[p] = s[p];
+    return t;
+};
+function cloneAgain(_a) {
+    var { a } = _a, clone = __rest(_a, ["a"]);
+}
+suddenly((_a) => {
+    var { x: a } = _a, rest = __rest(_a, ["x"]);
+    return rest.y;
+});
+suddenly((_a = { x: { z: 1, ka: 1 }, y: 'noo' }) => {
+    var _b = _a.x, { z = 12 } = _b, nested = __rest(_b, ["z"]), rest = __rest(_a, ["x"]);
+    return rest.y + nested.ka;
+});
diff --git a/tests/baselines/reference/objectRestParameter.symbols b/tests/baselines/reference/objectRestParameter.symbols
new file mode 100644
index 0000000000000..9569dc53d3a86
--- /dev/null
+++ b/tests/baselines/reference/objectRestParameter.symbols
@@ -0,0 +1,45 @@
+=== tests/cases/conformance/types/rest/objectRestParameter.ts ===
+function cloneAgain({ a, ...clone }: { a: number, b: string }): void {
+>cloneAgain : Symbol(cloneAgain, Decl(objectRestParameter.ts, 0, 0))
+>a : Symbol(a, Decl(objectRestParameter.ts, 0, 21))
+>clone : Symbol(clone, Decl(objectRestParameter.ts, 0, 24))
+>a : Symbol(a, Decl(objectRestParameter.ts, 0, 38))
+>b : Symbol(b, Decl(objectRestParameter.ts, 0, 49))
+}
+
+declare function suddenly(f: (a: { x: { z, ka }, y: string }) => void);
+>suddenly : Symbol(suddenly, Decl(objectRestParameter.ts, 1, 1))
+>f : Symbol(f, Decl(objectRestParameter.ts, 3, 26))
+>a : Symbol(a, Decl(objectRestParameter.ts, 3, 30))
+>x : Symbol(x, Decl(objectRestParameter.ts, 3, 34))
+>z : Symbol(z, Decl(objectRestParameter.ts, 3, 39))
+>ka : Symbol(ka, Decl(objectRestParameter.ts, 3, 42))
+>y : Symbol(y, Decl(objectRestParameter.ts, 3, 48))
+
+suddenly(({ x: a, ...rest }) => rest.y);
+>suddenly : Symbol(suddenly, Decl(objectRestParameter.ts, 1, 1))
+>x : Symbol(x, Decl(objectRestParameter.ts, 3, 34))
+>a : Symbol(a, Decl(objectRestParameter.ts, 4, 11))
+>rest : Symbol(rest, Decl(objectRestParameter.ts, 4, 17))
+>rest.y : Symbol(y, Decl(objectRestParameter.ts, 3, 48))
+>rest : Symbol(rest, Decl(objectRestParameter.ts, 4, 17))
+>y : Symbol(y, Decl(objectRestParameter.ts, 3, 48))
+
+suddenly(({ x: { z = 12, ...nested }, ...rest } = { x: { z: 1, ka: 1 }, y: 'noo' }) => rest.y + nested.ka);
+>suddenly : Symbol(suddenly, Decl(objectRestParameter.ts, 1, 1))
+>x : Symbol(x, Decl(objectRestParameter.ts, 3, 34))
+>z : Symbol(z, Decl(objectRestParameter.ts, 5, 16))
+>nested : Symbol(nested, Decl(objectRestParameter.ts, 5, 24))
+>rest : Symbol(rest, Decl(objectRestParameter.ts, 5, 37))
+>x : Symbol(x, Decl(objectRestParameter.ts, 5, 51))
+>z : Symbol(z, Decl(objectRestParameter.ts, 5, 56))
+>ka : Symbol(ka, Decl(objectRestParameter.ts, 5, 62))
+>y : Symbol(y, Decl(objectRestParameter.ts, 5, 71))
+>rest.y : Symbol(y, Decl(objectRestParameter.ts, 3, 48))
+>rest : Symbol(rest, Decl(objectRestParameter.ts, 5, 37))
+>y : Symbol(y, Decl(objectRestParameter.ts, 3, 48))
+>nested.ka : Symbol(ka, Decl(objectRestParameter.ts, 3, 42))
+>nested : Symbol(nested, Decl(objectRestParameter.ts, 5, 24))
+>ka : Symbol(ka, Decl(objectRestParameter.ts, 3, 42))
+
+
diff --git a/tests/baselines/reference/objectRestParameter.types b/tests/baselines/reference/objectRestParameter.types
new file mode 100644
index 0000000000000..c634c9c5cd530
--- /dev/null
+++ b/tests/baselines/reference/objectRestParameter.types
@@ -0,0 +1,56 @@
+=== tests/cases/conformance/types/rest/objectRestParameter.ts ===
+function cloneAgain({ a, ...clone }: { a: number, b: string }): void {
+>cloneAgain : ({a, ...clone}: { a: number; b: string; }) => void
+>a : number
+>clone : { b: string; }
+>a : number
+>b : string
+}
+
+declare function suddenly(f: (a: { x: { z, ka }, y: string }) => void);
+>suddenly : (f: (a: { x: { z: any; ka: any; }; y: string; }) => void) => any
+>f : (a: { x: { z: any; ka: any; }; y: string; }) => void
+>a : { x: { z: any; ka: any; }; y: string; }
+>x : { z: any; ka: any; }
+>z : any
+>ka : any
+>y : string
+
+suddenly(({ x: a, ...rest }) => rest.y);
+>suddenly(({ x: a, ...rest }) => rest.y) : any
+>suddenly : (f: (a: { x: { z: any; ka: any; }; y: string; }) => void) => any
+>({ x: a, ...rest }) => rest.y : ({x: a, ...rest}: { x: { z: any; ka: any; }; y: string; }) => string
+>x : any
+>a : { z: any; ka: any; }
+>rest : { y: string; }
+>rest.y : string
+>rest : { y: string; }
+>y : string
+
+suddenly(({ x: { z = 12, ...nested }, ...rest } = { x: { z: 1, ka: 1 }, y: 'noo' }) => rest.y + nested.ka);
+>suddenly(({ x: { z = 12, ...nested }, ...rest } = { x: { z: 1, ka: 1 }, y: 'noo' }) => rest.y + nested.ka) : any
+>suddenly : (f: (a: { x: { z: any; ka: any; }; y: string; }) => void) => any
+>({ x: { z = 12, ...nested }, ...rest } = { x: { z: 1, ka: 1 }, y: 'noo' }) => rest.y + nested.ka : ({x: {z, ...nested}, ...rest}?: { x: { z: any; ka: any; }; y: string; }) => string
+>x : any
+>z : any
+>12 : 12
+>nested : { ka: any; }
+>rest : { y: string; }
+>{ x: { z: 1, ka: 1 }, y: 'noo' } : { x: { z: number; ka: number; }; y: string; }
+>x : { z: number; ka: number; }
+>{ z: 1, ka: 1 } : { z: number; ka: number; }
+>z : number
+>1 : 1
+>ka : number
+>1 : 1
+>y : string
+>'noo' : "noo"
+>rest.y + nested.ka : string
+>rest.y : string
+>rest : { y: string; }
+>y : string
+>nested.ka : any
+>nested : { ka: any; }
+>ka : any
+
+
diff --git a/tests/baselines/reference/restElementMustBeLast.errors.txt b/tests/baselines/reference/restElementMustBeLast.errors.txt
index 269d984bc009c..5eb5a4cd2080f 100644
--- a/tests/baselines/reference/restElementMustBeLast.errors.txt
+++ b/tests/baselines/reference/restElementMustBeLast.errors.txt
@@ -1,12 +1,12 @@
-tests/cases/conformance/es6/destructuring/restElementMustBeLast.ts(1,9): error TS2462: A rest element must be last in an array destructuring pattern
-tests/cases/conformance/es6/destructuring/restElementMustBeLast.ts(2,2): error TS2462: A rest element must be last in an array destructuring pattern
+tests/cases/conformance/types/rest/restElementMustBeLast.ts(1,9): error TS2462: A rest element must be last in a destructuring pattern
+tests/cases/conformance/types/rest/restElementMustBeLast.ts(2,2): error TS2462: A rest element must be last in a destructuring pattern
 
 
-==== tests/cases/conformance/es6/destructuring/restElementMustBeLast.ts (2 errors) ====
+==== tests/cases/conformance/types/rest/restElementMustBeLast.ts (2 errors) ====
     var [...a, x] = [1, 2, 3];  // Error, rest must be last element
             ~
-!!! error TS2462: A rest element must be last in an array destructuring pattern
+!!! error TS2462: A rest element must be last in a destructuring pattern
     [...a, x] = [1, 2, 3];      // Error, rest must be last element
      ~~~~
-!!! error TS2462: A rest element must be last in an array destructuring pattern
+!!! error TS2462: A rest element must be last in a destructuring pattern
     
\ No newline at end of file
diff --git a/tests/baselines/reference/sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.js b/tests/baselines/reference/sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.js
index 9f7a70699bd1f..8355d61d9c38a 100644
--- a/tests/baselines/reference/sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.js
+++ b/tests/baselines/reference/sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.js
@@ -194,13 +194,13 @@ for (_b = getRobot(), _c = _b.name, nameA = _c === void 0 ? "noName" : _c, _b, i
 for (_d = { name: "trimmer", skill: "trimming" }, _e = _d.name, nameA = _e === void 0 ? "noName" : _e, _d, i = 0; i < 1; i++) {
     console.log(nameA);
 }
-for (_f = multiRobot.skills, _g = _f === void 0 ? { primary: "none", secondary: "none" } : _f, _h = _g.primary, primaryA = _h === void 0 ? "primary" : _h, _j = _g.secondary, secondaryA = _j === void 0 ? "secondary" : _j, multiRobot, i = 0; i < 1; i++) {
+for (_f = multiRobot.skills, _g = _f === void 0 ? { primary: "none", secondary: "none" } : _f, _h = _g.primary, primaryA = _h === void 0 ? "primary" : _h, _j = _g.secondary, secondaryA = _j === void 0 ? "secondary" : _j, multiRobot, multiRobot, i = 0; i < 1; i++) {
     console.log(primaryA);
 }
-for (_k = getMultiRobot(), _l = _k.skills, _m = _l === void 0 ? { primary: "none", secondary: "none" } : _l, _o = _m.primary, primaryA = _o === void 0 ? "primary" : _o, _p = _m.secondary, secondaryA = _p === void 0 ? "secondary" : _p, _k, i = 0; i < 1; i++) {
+for (_k = getMultiRobot(), (_l = _k.skills, _m = _l === void 0 ? { primary: "none", secondary: "none" } : _l, _o = _m.primary, primaryA = _o === void 0 ? "primary" : _o, _p = _m.secondary, secondaryA = _p === void 0 ? "secondary" : _p, _k), _k, i = 0; i < 1; i++) {
     console.log(primaryA);
 }
-for (_q = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, _r = _q.skills, _s = _r === void 0 ? { primary: "none", secondary: "none" } : _r, _t = _s.primary, primaryA = _t === void 0 ? "primary" : _t, _u = _s.secondary, secondaryA = _u === void 0 ? "secondary" : _u, _q,
+for (_q = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, (_r = _q.skills, _s = _r === void 0 ? { primary: "none", secondary: "none" } : _r, _t = _s.primary, primaryA = _t === void 0 ? "primary" : _t, _u = _s.secondary, secondaryA = _u === void 0 ? "secondary" : _u, _q), _q,
     i = 0; i < 1; i++) {
     console.log(primaryA);
 }
@@ -213,13 +213,13 @@ for (_w = getRobot(), _x = _w.name, name = _x === void 0 ? "noName" : _x, _w, i
 for (_y = { name: "trimmer", skill: "trimming" }, _z = _y.name, name = _z === void 0 ? "noName" : _z, _y, i = 0; i < 1; i++) {
     console.log(nameA);
 }
-for (_0 = multiRobot.skills, _1 = _0 === void 0 ? { primary: "none", secondary: "none" } : _0, _2 = _1.primary, primary = _2 === void 0 ? "primary" : _2, _3 = _1.secondary, secondary = _3 === void 0 ? "secondary" : _3, multiRobot, i = 0; i < 1; i++) {
+for (_0 = multiRobot.skills, _1 = _0 === void 0 ? { primary: "none", secondary: "none" } : _0, _2 = _1.primary, primary = _2 === void 0 ? "primary" : _2, _3 = _1.secondary, secondary = _3 === void 0 ? "secondary" : _3, multiRobot, multiRobot, i = 0; i < 1; i++) {
     console.log(primaryA);
 }
-for (_4 = getMultiRobot(), _5 = _4.skills, _6 = _5 === void 0 ? { primary: "none", secondary: "none" } : _5, _7 = _6.primary, primary = _7 === void 0 ? "primary" : _7, _8 = _6.secondary, secondary = _8 === void 0 ? "secondary" : _8, _4, i = 0; i < 1; i++) {
+for (_4 = getMultiRobot(), (_5 = _4.skills, _6 = _5 === void 0 ? { primary: "none", secondary: "none" } : _5, _7 = _6.primary, primary = _7 === void 0 ? "primary" : _7, _8 = _6.secondary, secondary = _8 === void 0 ? "secondary" : _8, _4), _4, i = 0; i < 1; i++) {
     console.log(primaryA);
 }
-for (_9 = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, _10 = _9.skills, _11 = _10 === void 0 ? { primary: "none", secondary: "none" } : _10, _12 = _11.primary, primary = _12 === void 0 ? "primary" : _12, _13 = _11.secondary, secondary = _13 === void 0 ? "secondary" : _13, _9,
+for (_9 = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, (_10 = _9.skills, _11 = _10 === void 0 ? { primary: "none", secondary: "none" } : _10, _12 = _11.primary, primary = _12 === void 0 ? "primary" : _12, _13 = _11.secondary, secondary = _13 === void 0 ? "secondary" : _13, _9), _9,
     i = 0; i < 1; i++) {
     console.log(primaryA);
 }
@@ -232,13 +232,13 @@ for (_16 = getRobot(), _17 = _16.name, nameA = _17 === void 0 ? "noName" : _17,
 for (_19 = { name: "trimmer", skill: "trimming" }, _20 = _19.name, nameA = _20 === void 0 ? "noName" : _20, _21 = _19.skill, skillA = _21 === void 0 ? "skill" : _21, _19, i = 0; i < 1; i++) {
     console.log(nameA);
 }
-for (_22 = multiRobot.name, nameA = _22 === void 0 ? "noName" : _22, _23 = multiRobot.skills, _24 = _23 === void 0 ? { primary: "none", secondary: "none" } : _23, _25 = _24.primary, primaryA = _25 === void 0 ? "primary" : _25, _26 = _24.secondary, secondaryA = _26 === void 0 ? "secondary" : _26, multiRobot, i = 0; i < 1; i++) {
+for (_22 = multiRobot.name, nameA = _22 === void 0 ? "noName" : _22, _23 = multiRobot.skills, _24 = _23 === void 0 ? { primary: "none", secondary: "none" } : _23, _25 = _24.primary, primaryA = _25 === void 0 ? "primary" : _25, _26 = _24.secondary, secondaryA = _26 === void 0 ? "secondary" : _26, multiRobot, multiRobot, i = 0; i < 1; i++) {
     console.log(primaryA);
 }
-for (_27 = getMultiRobot(), _28 = _27.name, nameA = _28 === void 0 ? "noName" : _28, _29 = _27.skills, _30 = _29 === void 0 ? { primary: "none", secondary: "none" } : _29, _31 = _30.primary, primaryA = _31 === void 0 ? "primary" : _31, _32 = _30.secondary, secondaryA = _32 === void 0 ? "secondary" : _32, _27, i = 0; i < 1; i++) {
+for (_27 = getMultiRobot(), (_28 = _27.name, nameA = _28 === void 0 ? "noName" : _28, _29 = _27.skills, _30 = _29 === void 0 ? { primary: "none", secondary: "none" } : _29, _31 = _30.primary, primaryA = _31 === void 0 ? "primary" : _31, _32 = _30.secondary, secondaryA = _32 === void 0 ? "secondary" : _32, _27), _27, i = 0; i < 1; i++) {
     console.log(primaryA);
 }
-for (_33 = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, _34 = _33.name, nameA = _34 === void 0 ? "noName" : _34, _35 = _33.skills, _36 = _35 === void 0 ? { primary: "none", secondary: "none" } : _35, _37 = _36.primary, primaryA = _37 === void 0 ? "primary" : _37, _38 = _36.secondary, secondaryA = _38 === void 0 ? "secondary" : _38, _33,
+for (_33 = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, (_34 = _33.name, nameA = _34 === void 0 ? "noName" : _34, _35 = _33.skills, _36 = _35 === void 0 ? { primary: "none", secondary: "none" } : _35, _37 = _36.primary, primaryA = _37 === void 0 ? "primary" : _37, _38 = _36.secondary, secondaryA = _38 === void 0 ? "secondary" : _38, _33), _33,
     i = 0; i < 1; i++) {
     console.log(primaryA);
 }
@@ -251,15 +251,16 @@ for (_41 = getRobot(), _42 = _41.name, name = _42 === void 0 ? "noName" : _42, _
 for (_44 = { name: "trimmer", skill: "trimming" }, _45 = _44.name, name = _45 === void 0 ? "noName" : _45, _46 = _44.skill, skill = _46 === void 0 ? "skill" : _46, _44, i = 0; i < 1; i++) {
     console.log(nameA);
 }
-for (_47 = multiRobot.name, name = _47 === void 0 ? "noName" : _47, _48 = multiRobot.skills, _49 = _48 === void 0 ? { primary: "none", secondary: "none" } : _48, _50 = _49.primary, primary = _50 === void 0 ? "primary" : _50, _51 = _49.secondary, secondary = _51 === void 0 ? "secondary" : _51, multiRobot, i = 0; i < 1; i++) {
+for (_47 = multiRobot.name, name = _47 === void 0 ? "noName" : _47, _48 = multiRobot.skills, _49 = _48 === void 0 ? { primary: "none", secondary: "none" } : _48, _50 = _49.primary, primary = _50 === void 0 ? "primary" : _50, _51 = _49.secondary, secondary = _51 === void 0 ? "secondary" : _51, multiRobot, multiRobot, i = 0; i < 1; i++) {
     console.log(primaryA);
 }
-for (_52 = getMultiRobot(), _53 = _52.name, name = _53 === void 0 ? "noName" : _53, _54 = _52.skills, _55 = _54 === void 0 ? { primary: "none", secondary: "none" } : _54, _56 = _55.primary, primary = _56 === void 0 ? "primary" : _56, _57 = _55.secondary, secondary = _57 === void 0 ? "secondary" : _57, _52, i = 0; i < 1; i++) {
+for (_52 = getMultiRobot(), (_53 = _52.name, name = _53 === void 0 ? "noName" : _53, _54 = _52.skills, _55 = _54 === void 0 ? { primary: "none", secondary: "none" } : _54, _56 = _55.primary, primary = _56 === void 0 ? "primary" : _56, _57 = _55.secondary, secondary = _57 === void 0 ? "secondary" : _57, _52), _52, i = 0; i < 1; i++) {
     console.log(primaryA);
 }
-for (_58 = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, _59 = _58.name, name = _59 === void 0 ? "noName" : _59, _60 = _58.skills, _61 = _60 === void 0 ? { primary: "none", secondary: "none" } : _60, _62 = _61.primary, primary = _62 === void 0 ? "primary" : _62, _63 = _61.secondary, secondary = _63 === void 0 ? "secondary" : _63, _58,
+for (_58 = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, (_59 = _58.name, name = _59 === void 0 ? "noName" : _59, _60 = _58.skills, _61 = _60 === void 0 ? { primary: "none", secondary: "none" } : _60, _62 = _61.primary, primary = _62 === void 0 ? "primary" : _62, _63 = _61.secondary, secondary = _63 === void 0 ? "secondary" : _63, _58), _58,
     i = 0; i < 1; i++) {
     console.log(primaryA);
 }
-var _a, _b, _c, _d, _e, _f, _g, _h, _j, _k, _l, _m, _o, _p, _q, _r, _s, _t, _u, _v, _w, _x, _y, _z, _0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, _25, _26, _27, _28, _29, _30, _31, _32, _33, _34, _35, _36, _37, _38, _39, _40, _41, _42, _43, _44, _45, _46, _47, _48, _49, _50, _51, _52, _53, _54, _55, _56, _57, _58, _59, _60, _61, _62, _63;
+var _k, _q, _4, _9, _27, _33, _52, _58;
+var _a, _b, _c, _d, _e, _f, _g, _h, _j, _l, _m, _o, _p, _r, _s, _t, _u, _v, _w, _x, _y, _z, _0, _1, _2, _3, _5, _6, _7, _8, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, _25, _26, _28, _29, _30, _31, _32, _34, _35, _36, _37, _38, _39, _40, _41, _42, _43, _44, _45, _46, _47, _48, _49, _50, _51, _53, _54, _55, _56, _57, _59, _60, _61, _62, _63;
 //# sourceMappingURL=sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.js.map b/tests/baselines/reference/sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.js.map
index dd248e8994414..56f8aa0f607ef 100644
--- a/tests/baselines/reference/sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.js.map
+++ b/tests/baselines/reference/sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.js.map
@@ -1,2 +1,2 @@
 //// [sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.js.map]
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diff --git a/tests/baselines/reference/sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.sourcemap.txt b/tests/baselines/reference/sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.sourcemap.txt
index 97271e8f3d039..9e0e92d4a689e 100644
--- a/tests/baselines/reference/sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.sourcemap.txt
+++ b/tests/baselines/reference/sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.sourcemap.txt
@@ -594,14 +594,14 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(19, 1) Source(37, 1) + SourceIndex(0)
 2 >Emitted(19, 2) Source(37, 2) + SourceIndex(0)
 ---
->>>for (_f = multiRobot.skills, _g = _f === void 0 ? { primary: "none", secondary: "none" } : _f, _h = _g.primary, primaryA = _h === void 0 ? "primary" : _h, _j = _g.secondary, secondaryA = _j === void 0 ? "secondary" : _j, multiRobot, i = 0; i < 1; i++) {
+>>>for (_f = multiRobot.skills, _g = _f === void 0 ? { primary: "none", secondary: "none" } : _f, _h = _g.primary, primaryA = _h === void 0 ? "primary" : _h, _j = _g.secondary, secondaryA = _j === void 0 ? "secondary" : _j, multiRobot, multiRobot, i = 0; i < 1; i++) {
 1->
 2 >^^^
 3 >   ^
@@ -620,18 +620,20 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 16>                                                                                                                                                                                                                           ^^
 17>                                                                                                                                                                                                                             ^^^^^^^^^^
 18>                                                                                                                                                                                                                                       ^^
-19>                                                                                                                                                                                                                                         ^
-20>                                                                                                                                                                                                                                          ^^^
-21>                                                                                                                                                                                                                                             ^
-22>                                                                                                                                                                                                                                              ^^
-23>                                                                                                                                                                                                                                                ^
-24>                                                                                                                                                                                                                                                 ^^^
-25>                                                                                                                                                                                                                                                    ^
-26>                                                                                                                                                                                                                                                     ^^
-27>                                                                                                                                                                                                                                                       ^
-28>                                                                                                                                                                                                                                                        ^^
-29>                                                                                                                                                                                                                                                          ^^
-30>                                                                                                                                                                                                                                                            ^
+19>                                                                                                                                                                                                                                         ^^^^^^^^^^
+20>                                                                                                                                                                                                                                                   ^^
+21>                                                                                                                                                                                                                                                     ^
+22>                                                                                                                                                                                                                                                      ^^^
+23>                                                                                                                                                                                                                                                         ^
+24>                                                                                                                                                                                                                                                          ^^
+25>                                                                                                                                                                                                                                                            ^
+26>                                                                                                                                                                                                                                                             ^^^
+27>                                                                                                                                                                                                                                                                ^
+28>                                                                                                                                                                                                                                                                 ^^
+29>                                                                                                                                                                                                                                                                   ^
+30>                                                                                                                                                                                                                                                                    ^^
+31>                                                                                                                                                                                                                                                                      ^^
+32>                                                                                                                                                                                                                                                                        ^
 1->
   >
 2 >for
@@ -660,19 +662,21 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
   >                                                                                                                                                                                                                               } = { primary: "none", secondary: "none" }
   >                                                                                                                                                                                                                           } = 
 17>                                                                                                                                                                                                                             multiRobot
-18>                                                                                                                                                                                                                                       , 
-19>                                                                                                                                                                                                                                         i
-20>                                                                                                                                                                                                                                           = 
-21>                                                                                                                                                                                                                                             0
-22>                                                                                                                                                                                                                                              ; 
-23>                                                                                                                                                                                                                                                i
-24>                                                                                                                                                                                                                                                  < 
-25>                                                                                                                                                                                                                                                    1
-26>                                                                                                                                                                                                                                                     ; 
-27>                                                                                                                                                                                                                                                       i
-28>                                                                                                                                                                                                                                                        ++
-29>                                                                                                                                                                                                                                                          ) 
-30>                                                                                                                                                                                                                                                            {
+18>                                                                                                                                                                                                                                       
+19>                                                                                                                                                                                                                                         multiRobot
+20>                                                                                                                                                                                                                                                   , 
+21>                                                                                                                                                                                                                                                     i
+22>                                                                                                                                                                                                                                                       = 
+23>                                                                                                                                                                                                                                                         0
+24>                                                                                                                                                                                                                                                          ; 
+25>                                                                                                                                                                                                                                                            i
+26>                                                                                                                                                                                                                                                              < 
+27>                                                                                                                                                                                                                                                                1
+28>                                                                                                                                                                                                                                                                 ; 
+29>                                                                                                                                                                                                                                                                   i
+30>                                                                                                                                                                                                                                                                    ++
+31>                                                                                                                                                                                                                                                                      ) 
+32>                                                                                                                                                                                                                                                                        {
 1->Emitted(20, 1) Source(38, 1) + SourceIndex(0)
 2 >Emitted(20, 4) Source(38, 4) + SourceIndex(0)
 3 >Emitted(20, 5) Source(38, 5) + SourceIndex(0)
@@ -690,19 +694,21 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 15>Emitted(20, 220) Source(41, 44) + SourceIndex(0)
 16>Emitted(20, 222) Source(43, 5) + SourceIndex(0)
 17>Emitted(20, 232) Source(43, 15) + SourceIndex(0)
-18>Emitted(20, 234) Source(43, 17) + SourceIndex(0)
-19>Emitted(20, 235) Source(43, 18) + SourceIndex(0)
-20>Emitted(20, 238) Source(43, 21) + SourceIndex(0)
-21>Emitted(20, 239) Source(43, 22) + SourceIndex(0)
-22>Emitted(20, 241) Source(43, 24) + SourceIndex(0)
-23>Emitted(20, 242) Source(43, 25) + SourceIndex(0)
-24>Emitted(20, 245) Source(43, 28) + SourceIndex(0)
-25>Emitted(20, 246) Source(43, 29) + SourceIndex(0)
-26>Emitted(20, 248) Source(43, 31) + SourceIndex(0)
-27>Emitted(20, 249) Source(43, 32) + SourceIndex(0)
-28>Emitted(20, 251) Source(43, 34) + SourceIndex(0)
-29>Emitted(20, 253) Source(43, 36) + SourceIndex(0)
-30>Emitted(20, 254) Source(43, 37) + SourceIndex(0)
+18>Emitted(20, 234) Source(43, 5) + SourceIndex(0)
+19>Emitted(20, 244) Source(43, 15) + SourceIndex(0)
+20>Emitted(20, 246) Source(43, 17) + SourceIndex(0)
+21>Emitted(20, 247) Source(43, 18) + SourceIndex(0)
+22>Emitted(20, 250) Source(43, 21) + SourceIndex(0)
+23>Emitted(20, 251) Source(43, 22) + SourceIndex(0)
+24>Emitted(20, 253) Source(43, 24) + SourceIndex(0)
+25>Emitted(20, 254) Source(43, 25) + SourceIndex(0)
+26>Emitted(20, 257) Source(43, 28) + SourceIndex(0)
+27>Emitted(20, 258) Source(43, 29) + SourceIndex(0)
+28>Emitted(20, 260) Source(43, 31) + SourceIndex(0)
+29>Emitted(20, 261) Source(43, 32) + SourceIndex(0)
+30>Emitted(20, 263) Source(43, 34) + SourceIndex(0)
+31>Emitted(20, 265) Source(43, 36) + SourceIndex(0)
+32>Emitted(20, 266) Source(43, 37) + SourceIndex(0)
 ---
 >>>    console.log(primaryA);
 1 >^^^^
@@ -734,44 +740,44 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(22, 1) Source(45, 1) + SourceIndex(0)
 2 >Emitted(22, 2) Source(45, 2) + SourceIndex(0)
 ---
->>>for (_k = getMultiRobot(), _l = _k.skills, _m = _l === void 0 ? { primary: "none", secondary: "none" } : _l, _o = _m.primary, primaryA = _o === void 0 ? "primary" : _o, _p = _m.secondary, secondaryA = _p === void 0 ? "secondary" : _p, _k, i = 0; i < 1; i++) {
+>>>for (_k = getMultiRobot(), (_l = _k.skills, _m = _l === void 0 ? { primary: "none", secondary: "none" } : _l, _o = _m.primary, primaryA = _o === void 0 ? "primary" : _o, _p = _m.secondary, secondaryA = _p === void 0 ? "secondary" : _p, _k), _k, i = 0; i < 1; i++) {
 1->
 2 >^^^
 3 >   ^
 4 >    ^
 5 >     ^^^^^^^^^^^^^^^^^^^^
-6 >                         ^^
-7 >                           ^^^^^^^^^^^^^^
-8 >                                         ^^
-9 >                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-10>                                                                                                           ^^
-11>                                                                                                             ^^^^^^^^^^^^^^^
-12>                                                                                                                            ^^
-13>                                                                                                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-14>                                                                                                                                                                       ^^
-15>                                                                                                                                                                         ^^^^^^^^^^^^^^^^^
-16>                                                                                                                                                                                          ^^
-17>                                                                                                                                                                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-18>                                                                                                                                                                                                                                         ^^^^^^
-19>                                                                                                                                                                                                                                               ^
-20>                                                                                                                                                                                                                                                ^^^
-21>                                                                                                                                                                                                                                                   ^
-22>                                                                                                                                                                                                                                                    ^^
-23>                                                                                                                                                                                                                                                      ^
-24>                                                                                                                                                                                                                                                       ^^^
-25>                                                                                                                                                                                                                                                          ^
-26>                                                                                                                                                                                                                                                           ^^
-27>                                                                                                                                                                                                                                                             ^
-28>                                                                                                                                                                                                                                                              ^^
-29>                                                                                                                                                                                                                                                                ^^
-30>                                                                                                                                                                                                                                                                  ^
+6 >                         ^^^
+7 >                            ^^^^^^^^^^^^^^
+8 >                                          ^^
+9 >                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+10>                                                                                                            ^^
+11>                                                                                                              ^^^^^^^^^^^^^^^
+12>                                                                                                                             ^^
+13>                                                                                                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+14>                                                                                                                                                                        ^^
+15>                                                                                                                                                                          ^^^^^^^^^^^^^^^^^
+16>                                                                                                                                                                                           ^^
+17>                                                                                                                                                                                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+18>                                                                                                                                                                                                                                          ^^^^^^^^^^^
+19>                                                                                                                                                                                                                                                     ^
+20>                                                                                                                                                                                                                                                      ^^^
+21>                                                                                                                                                                                                                                                         ^
+22>                                                                                                                                                                                                                                                          ^^
+23>                                                                                                                                                                                                                                                            ^
+24>                                                                                                                                                                                                                                                             ^^^
+25>                                                                                                                                                                                                                                                                ^
+26>                                                                                                                                                                                                                                                                 ^^
+27>                                                                                                                                                                                                                                                                   ^
+28>                                                                                                                                                                                                                                                                    ^^
+29>                                                                                                                                                                                                                                                                      ^^
+30>                                                                                                                                                                                                                                                                        ^
 1->
   >
 2 >for
@@ -784,69 +790,69 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
   >         } = { primary: "none", secondary: "none" }
   >     } = getMultiRobot()
 6 >                         
-7 >                           skills: {
-  >                                   primary: primaryA = "primary",
-  >                                   secondary: secondaryA = "secondary"
-  >                               } = { primary: "none", secondary: "none" }
-8 >                                         
-9 >                                           skills: {
-  >                                                   primary: primaryA = "primary",
-  >                                                   secondary: secondaryA = "secondary"
-  >                                               } = { primary: "none", secondary: "none" }
-10>                                                                                                           
-11>                                                                                                             primary: primaryA = "primary"
-12>                                                                                                                            
-13>                                                                                                                              primary: primaryA = "primary"
-14>                                                                                                                                                                       ,
-  >                                                                                                                                                                               
-15>                                                                                                                                                                         secondary: secondaryA = "secondary"
-16>                                                                                                                                                                                          
-17>                                                                                                                                                                                            secondary: secondaryA = "secondary"
-18>                                                                                                                                                                                                                                         
-  >                                                                                                                                                                                                                                             } = { primary: "none", secondary: "none" }
-  >                                                                                                                                                                                                                                         } = getMultiRobot(), 
-19>                                                                                                                                                                                                                                               i
-20>                                                                                                                                                                                                                                                 = 
-21>                                                                                                                                                                                                                                                   0
-22>                                                                                                                                                                                                                                                    ; 
-23>                                                                                                                                                                                                                                                      i
-24>                                                                                                                                                                                                                                                        < 
-25>                                                                                                                                                                                                                                                          1
-26>                                                                                                                                                                                                                                                           ; 
-27>                                                                                                                                                                                                                                                             i
-28>                                                                                                                                                                                                                                                              ++
-29>                                                                                                                                                                                                                                                                ) 
-30>                                                                                                                                                                                                                                                                  {
+7 >                            skills: {
+  >                                    primary: primaryA = "primary",
+  >                                    secondary: secondaryA = "secondary"
+  >                                } = { primary: "none", secondary: "none" }
+8 >                                          
+9 >                                            skills: {
+  >                                                    primary: primaryA = "primary",
+  >                                                    secondary: secondaryA = "secondary"
+  >                                                } = { primary: "none", secondary: "none" }
+10>                                                                                                            
+11>                                                                                                              primary: primaryA = "primary"
+12>                                                                                                                             
+13>                                                                                                                               primary: primaryA = "primary"
+14>                                                                                                                                                                        ,
+  >                                                                                                                                                                                
+15>                                                                                                                                                                          secondary: secondaryA = "secondary"
+16>                                                                                                                                                                                           
+17>                                                                                                                                                                                             secondary: secondaryA = "secondary"
+18>                                                                                                                                                                                                                                          
+  >                                                                                                                                                                                                                                              } = { primary: "none", secondary: "none" }
+  >                                                                                                                                                                                                                                          } = getMultiRobot(), 
+19>                                                                                                                                                                                                                                                     i
+20>                                                                                                                                                                                                                                                       = 
+21>                                                                                                                                                                                                                                                         0
+22>                                                                                                                                                                                                                                                          ; 
+23>                                                                                                                                                                                                                                                            i
+24>                                                                                                                                                                                                                                                              < 
+25>                                                                                                                                                                                                                                                                1
+26>                                                                                                                                                                                                                                                                 ; 
+27>                                                                                                                                                                                                                                                                   i
+28>                                                                                                                                                                                                                                                                    ++
+29>                                                                                                                                                                                                                                                                      ) 
+30>                                                                                                                                                                                                                                                                        {
 1->Emitted(23, 1) Source(46, 1) + SourceIndex(0)
 2 >Emitted(23, 4) Source(46, 4) + SourceIndex(0)
 3 >Emitted(23, 5) Source(46, 5) + SourceIndex(0)
 4 >Emitted(23, 6) Source(46, 6) + SourceIndex(0)
 5 >Emitted(23, 26) Source(51, 20) + SourceIndex(0)
-6 >Emitted(23, 28) Source(47, 5) + SourceIndex(0)
-7 >Emitted(23, 42) Source(50, 47) + SourceIndex(0)
-8 >Emitted(23, 44) Source(47, 5) + SourceIndex(0)
-9 >Emitted(23, 108) Source(50, 47) + SourceIndex(0)
-10>Emitted(23, 110) Source(48, 9) + SourceIndex(0)
-11>Emitted(23, 125) Source(48, 38) + SourceIndex(0)
-12>Emitted(23, 127) Source(48, 9) + SourceIndex(0)
-13>Emitted(23, 168) Source(48, 38) + SourceIndex(0)
-14>Emitted(23, 170) Source(49, 9) + SourceIndex(0)
-15>Emitted(23, 187) Source(49, 44) + SourceIndex(0)
-16>Emitted(23, 189) Source(49, 9) + SourceIndex(0)
-17>Emitted(23, 234) Source(49, 44) + SourceIndex(0)
-18>Emitted(23, 240) Source(51, 22) + SourceIndex(0)
-19>Emitted(23, 241) Source(51, 23) + SourceIndex(0)
-20>Emitted(23, 244) Source(51, 26) + SourceIndex(0)
-21>Emitted(23, 245) Source(51, 27) + SourceIndex(0)
-22>Emitted(23, 247) Source(51, 29) + SourceIndex(0)
-23>Emitted(23, 248) Source(51, 30) + SourceIndex(0)
-24>Emitted(23, 251) Source(51, 33) + SourceIndex(0)
-25>Emitted(23, 252) Source(51, 34) + SourceIndex(0)
-26>Emitted(23, 254) Source(51, 36) + SourceIndex(0)
-27>Emitted(23, 255) Source(51, 37) + SourceIndex(0)
-28>Emitted(23, 257) Source(51, 39) + SourceIndex(0)
-29>Emitted(23, 259) Source(51, 41) + SourceIndex(0)
-30>Emitted(23, 260) Source(51, 42) + SourceIndex(0)
+6 >Emitted(23, 29) Source(47, 5) + SourceIndex(0)
+7 >Emitted(23, 43) Source(50, 47) + SourceIndex(0)
+8 >Emitted(23, 45) Source(47, 5) + SourceIndex(0)
+9 >Emitted(23, 109) Source(50, 47) + SourceIndex(0)
+10>Emitted(23, 111) Source(48, 9) + SourceIndex(0)
+11>Emitted(23, 126) Source(48, 38) + SourceIndex(0)
+12>Emitted(23, 128) Source(48, 9) + SourceIndex(0)
+13>Emitted(23, 169) Source(48, 38) + SourceIndex(0)
+14>Emitted(23, 171) Source(49, 9) + SourceIndex(0)
+15>Emitted(23, 188) Source(49, 44) + SourceIndex(0)
+16>Emitted(23, 190) Source(49, 9) + SourceIndex(0)
+17>Emitted(23, 235) Source(49, 44) + SourceIndex(0)
+18>Emitted(23, 246) Source(51, 22) + SourceIndex(0)
+19>Emitted(23, 247) Source(51, 23) + SourceIndex(0)
+20>Emitted(23, 250) Source(51, 26) + SourceIndex(0)
+21>Emitted(23, 251) Source(51, 27) + SourceIndex(0)
+22>Emitted(23, 253) Source(51, 29) + SourceIndex(0)
+23>Emitted(23, 254) Source(51, 30) + SourceIndex(0)
+24>Emitted(23, 257) Source(51, 33) + SourceIndex(0)
+25>Emitted(23, 258) Source(51, 34) + SourceIndex(0)
+26>Emitted(23, 260) Source(51, 36) + SourceIndex(0)
+27>Emitted(23, 261) Source(51, 37) + SourceIndex(0)
+28>Emitted(23, 263) Source(51, 39) + SourceIndex(0)
+29>Emitted(23, 265) Source(51, 41) + SourceIndex(0)
+30>Emitted(23, 266) Source(51, 42) + SourceIndex(0)
 ---
 >>>    console.log(primaryA);
 1 >^^^^
@@ -878,31 +884,31 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(25, 1) Source(53, 1) + SourceIndex(0)
 2 >Emitted(25, 2) Source(53, 2) + SourceIndex(0)
 ---
->>>for (_q = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, _r = _q.skills, _s = _r === void 0 ? { primary: "none", secondary: "none" } : _r, _t = _s.primary, primaryA = _t === void 0 ? "primary" : _t, _u = _s.secondary, secondaryA = _u === void 0 ? "secondary" : _u, _q,
+>>>for (_q = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, (_r = _q.skills, _s = _r === void 0 ? { primary: "none", secondary: "none" } : _r, _t = _s.primary, primaryA = _t === void 0 ? "primary" : _t, _u = _s.secondary, secondaryA = _u === void 0 ? "secondary" : _u, _q), _q,
 1->
 2 >^^^
 3 >   ^
 4 >    ^
 5 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-6 >                                                                                   ^^
-7 >                                                                                     ^^^^^^^^^^^^^^
-8 >                                                                                                   ^^
-9 >                                                                                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-10>                                                                                                                                                                     ^^
-11>                                                                                                                                                                       ^^^^^^^^^^^^^^^
-12>                                                                                                                                                                                      ^^
-13>                                                                                                                                                                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-14>                                                                                                                                                                                                                                 ^^
-15>                                                                                                                                                                                                                                   ^^^^^^^^^^^^^^^^^
-16>                                                                                                                                                                                                                                                    ^^
-17>                                                                                                                                                                                                                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+6 >                                                                                   ^^^
+7 >                                                                                      ^^^^^^^^^^^^^^
+8 >                                                                                                    ^^
+9 >                                                                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+10>                                                                                                                                                                      ^^
+11>                                                                                                                                                                        ^^^^^^^^^^^^^^^
+12>                                                                                                                                                                                       ^^
+13>                                                                                                                                                                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+14>                                                                                                                                                                                                                                  ^^
+15>                                                                                                                                                                                                                                    ^^^^^^^^^^^^^^^^^
+16>                                                                                                                                                                                                                                                     ^^
+17>                                                                                                                                                                                                                                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 1->
   >
 2 >for
@@ -915,41 +921,41 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
   >         } = { primary: "none", secondary: "none" }
   >     } = <MultiRobot>{ name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }
 6 >                                                                                   
-7 >                                                                                     skills: {
-  >                                                                                             primary: primaryA = "primary",
-  >                                                                                             secondary: secondaryA = "secondary"
-  >                                                                                         } = { primary: "none", secondary: "none" }
-8 >                                                                                                   
-9 >                                                                                                     skills: {
-  >                                                                                                             primary: primaryA = "primary",
-  >                                                                                                             secondary: secondaryA = "secondary"
-  >                                                                                                         } = { primary: "none", secondary: "none" }
-10>                                                                                                                                                                     
-11>                                                                                                                                                                       primary: primaryA = "primary"
-12>                                                                                                                                                                                      
-13>                                                                                                                                                                                        primary: primaryA = "primary"
-14>                                                                                                                                                                                                                                 ,
-  >                                                                                                                                                                                                                                         
-15>                                                                                                                                                                                                                                   secondary: secondaryA = "secondary"
-16>                                                                                                                                                                                                                                                    
-17>                                                                                                                                                                                                                                                      secondary: secondaryA = "secondary"
+7 >                                                                                      skills: {
+  >                                                                                              primary: primaryA = "primary",
+  >                                                                                              secondary: secondaryA = "secondary"
+  >                                                                                          } = { primary: "none", secondary: "none" }
+8 >                                                                                                    
+9 >                                                                                                      skills: {
+  >                                                                                                              primary: primaryA = "primary",
+  >                                                                                                              secondary: secondaryA = "secondary"
+  >                                                                                                          } = { primary: "none", secondary: "none" }
+10>                                                                                                                                                                      
+11>                                                                                                                                                                        primary: primaryA = "primary"
+12>                                                                                                                                                                                       
+13>                                                                                                                                                                                         primary: primaryA = "primary"
+14>                                                                                                                                                                                                                                  ,
+  >                                                                                                                                                                                                                                          
+15>                                                                                                                                                                                                                                    secondary: secondaryA = "secondary"
+16>                                                                                                                                                                                                                                                     
+17>                                                                                                                                                                                                                                                       secondary: secondaryA = "secondary"
 1->Emitted(26, 1) Source(54, 1) + SourceIndex(0)
 2 >Emitted(26, 4) Source(54, 4) + SourceIndex(0)
 3 >Emitted(26, 5) Source(54, 5) + SourceIndex(0)
 4 >Emitted(26, 6) Source(54, 6) + SourceIndex(0)
 5 >Emitted(26, 84) Source(59, 90) + SourceIndex(0)
-6 >Emitted(26, 86) Source(55, 5) + SourceIndex(0)
-7 >Emitted(26, 100) Source(58, 47) + SourceIndex(0)
-8 >Emitted(26, 102) Source(55, 5) + SourceIndex(0)
-9 >Emitted(26, 166) Source(58, 47) + SourceIndex(0)
-10>Emitted(26, 168) Source(56, 9) + SourceIndex(0)
-11>Emitted(26, 183) Source(56, 38) + SourceIndex(0)
-12>Emitted(26, 185) Source(56, 9) + SourceIndex(0)
-13>Emitted(26, 226) Source(56, 38) + SourceIndex(0)
-14>Emitted(26, 228) Source(57, 9) + SourceIndex(0)
-15>Emitted(26, 245) Source(57, 44) + SourceIndex(0)
-16>Emitted(26, 247) Source(57, 9) + SourceIndex(0)
-17>Emitted(26, 292) Source(57, 44) + SourceIndex(0)
+6 >Emitted(26, 87) Source(55, 5) + SourceIndex(0)
+7 >Emitted(26, 101) Source(58, 47) + SourceIndex(0)
+8 >Emitted(26, 103) Source(55, 5) + SourceIndex(0)
+9 >Emitted(26, 167) Source(58, 47) + SourceIndex(0)
+10>Emitted(26, 169) Source(56, 9) + SourceIndex(0)
+11>Emitted(26, 184) Source(56, 38) + SourceIndex(0)
+12>Emitted(26, 186) Source(56, 9) + SourceIndex(0)
+13>Emitted(26, 227) Source(56, 38) + SourceIndex(0)
+14>Emitted(26, 229) Source(57, 9) + SourceIndex(0)
+15>Emitted(26, 246) Source(57, 44) + SourceIndex(0)
+16>Emitted(26, 248) Source(57, 9) + SourceIndex(0)
+17>Emitted(26, 293) Source(57, 44) + SourceIndex(0)
 ---
 >>>    i = 0; i < 1; i++) {
 1 >^^^^
@@ -1345,14 +1351,14 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(38, 1) Source(72, 1) + SourceIndex(0)
 2 >Emitted(38, 2) Source(72, 2) + SourceIndex(0)
 ---
->>>for (_0 = multiRobot.skills, _1 = _0 === void 0 ? { primary: "none", secondary: "none" } : _0, _2 = _1.primary, primary = _2 === void 0 ? "primary" : _2, _3 = _1.secondary, secondary = _3 === void 0 ? "secondary" : _3, multiRobot, i = 0; i < 1; i++) {
+>>>for (_0 = multiRobot.skills, _1 = _0 === void 0 ? { primary: "none", secondary: "none" } : _0, _2 = _1.primary, primary = _2 === void 0 ? "primary" : _2, _3 = _1.secondary, secondary = _3 === void 0 ? "secondary" : _3, multiRobot, multiRobot, i = 0; i < 1; i++) {
 1->
 2 >^^^
 3 >   ^
@@ -1371,18 +1377,20 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 16>                                                                                                                                                                                                                         ^^
 17>                                                                                                                                                                                                                           ^^^^^^^^^^
 18>                                                                                                                                                                                                                                     ^^
-19>                                                                                                                                                                                                                                       ^
-20>                                                                                                                                                                                                                                        ^^^
-21>                                                                                                                                                                                                                                           ^
-22>                                                                                                                                                                                                                                            ^^
-23>                                                                                                                                                                                                                                              ^
-24>                                                                                                                                                                                                                                               ^^^
-25>                                                                                                                                                                                                                                                  ^
-26>                                                                                                                                                                                                                                                   ^^
-27>                                                                                                                                                                                                                                                     ^
-28>                                                                                                                                                                                                                                                      ^^
-29>                                                                                                                                                                                                                                                        ^^
-30>                                                                                                                                                                                                                                                          ^
+19>                                                                                                                                                                                                                                       ^^^^^^^^^^
+20>                                                                                                                                                                                                                                                 ^^
+21>                                                                                                                                                                                                                                                   ^
+22>                                                                                                                                                                                                                                                    ^^^
+23>                                                                                                                                                                                                                                                       ^
+24>                                                                                                                                                                                                                                                        ^^
+25>                                                                                                                                                                                                                                                          ^
+26>                                                                                                                                                                                                                                                           ^^^
+27>                                                                                                                                                                                                                                                              ^
+28>                                                                                                                                                                                                                                                               ^^
+29>                                                                                                                                                                                                                                                                 ^
+30>                                                                                                                                                                                                                                                                  ^^
+31>                                                                                                                                                                                                                                                                    ^^
+32>                                                                                                                                                                                                                                                                      ^
 1->
   >
 2 >for
@@ -1411,19 +1419,21 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
   >                                                                                                                                                                                                                             } = { primary: "none", secondary: "none" }
   >                                                                                                                                                                                                                         } = 
 17>                                                                                                                                                                                                                           multiRobot
-18>                                                                                                                                                                                                                                     , 
-19>                                                                                                                                                                                                                                       i
-20>                                                                                                                                                                                                                                         = 
-21>                                                                                                                                                                                                                                           0
-22>                                                                                                                                                                                                                                            ; 
-23>                                                                                                                                                                                                                                              i
-24>                                                                                                                                                                                                                                                < 
-25>                                                                                                                                                                                                                                                  1
-26>                                                                                                                                                                                                                                                   ; 
-27>                                                                                                                                                                                                                                                     i
-28>                                                                                                                                                                                                                                                      ++
-29>                                                                                                                                                                                                                                                        ) 
-30>                                                                                                                                                                                                                                                          {
+18>                                                                                                                                                                                                                                     
+19>                                                                                                                                                                                                                                       multiRobot
+20>                                                                                                                                                                                                                                                 , 
+21>                                                                                                                                                                                                                                                   i
+22>                                                                                                                                                                                                                                                     = 
+23>                                                                                                                                                                                                                                                       0
+24>                                                                                                                                                                                                                                                        ; 
+25>                                                                                                                                                                                                                                                          i
+26>                                                                                                                                                                                                                                                            < 
+27>                                                                                                                                                                                                                                                              1
+28>                                                                                                                                                                                                                                                               ; 
+29>                                                                                                                                                                                                                                                                 i
+30>                                                                                                                                                                                                                                                                  ++
+31>                                                                                                                                                                                                                                                                    ) 
+32>                                                                                                                                                                                                                                                                      {
 1->Emitted(39, 1) Source(73, 1) + SourceIndex(0)
 2 >Emitted(39, 4) Source(73, 4) + SourceIndex(0)
 3 >Emitted(39, 5) Source(73, 5) + SourceIndex(0)
@@ -1441,19 +1451,21 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 15>Emitted(39, 218) Source(76, 32) + SourceIndex(0)
 16>Emitted(39, 220) Source(78, 5) + SourceIndex(0)
 17>Emitted(39, 230) Source(78, 15) + SourceIndex(0)
-18>Emitted(39, 232) Source(78, 17) + SourceIndex(0)
-19>Emitted(39, 233) Source(78, 18) + SourceIndex(0)
-20>Emitted(39, 236) Source(78, 21) + SourceIndex(0)
-21>Emitted(39, 237) Source(78, 22) + SourceIndex(0)
-22>Emitted(39, 239) Source(78, 24) + SourceIndex(0)
-23>Emitted(39, 240) Source(78, 25) + SourceIndex(0)
-24>Emitted(39, 243) Source(78, 28) + SourceIndex(0)
-25>Emitted(39, 244) Source(78, 29) + SourceIndex(0)
-26>Emitted(39, 246) Source(78, 31) + SourceIndex(0)
-27>Emitted(39, 247) Source(78, 32) + SourceIndex(0)
-28>Emitted(39, 249) Source(78, 34) + SourceIndex(0)
-29>Emitted(39, 251) Source(78, 36) + SourceIndex(0)
-30>Emitted(39, 252) Source(78, 37) + SourceIndex(0)
+18>Emitted(39, 232) Source(78, 5) + SourceIndex(0)
+19>Emitted(39, 242) Source(78, 15) + SourceIndex(0)
+20>Emitted(39, 244) Source(78, 17) + SourceIndex(0)
+21>Emitted(39, 245) Source(78, 18) + SourceIndex(0)
+22>Emitted(39, 248) Source(78, 21) + SourceIndex(0)
+23>Emitted(39, 249) Source(78, 22) + SourceIndex(0)
+24>Emitted(39, 251) Source(78, 24) + SourceIndex(0)
+25>Emitted(39, 252) Source(78, 25) + SourceIndex(0)
+26>Emitted(39, 255) Source(78, 28) + SourceIndex(0)
+27>Emitted(39, 256) Source(78, 29) + SourceIndex(0)
+28>Emitted(39, 258) Source(78, 31) + SourceIndex(0)
+29>Emitted(39, 259) Source(78, 32) + SourceIndex(0)
+30>Emitted(39, 261) Source(78, 34) + SourceIndex(0)
+31>Emitted(39, 263) Source(78, 36) + SourceIndex(0)
+32>Emitted(39, 264) Source(78, 37) + SourceIndex(0)
 ---
 >>>    console.log(primaryA);
 1 >^^^^
@@ -1485,44 +1497,44 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(41, 1) Source(80, 1) + SourceIndex(0)
 2 >Emitted(41, 2) Source(80, 2) + SourceIndex(0)
 ---
->>>for (_4 = getMultiRobot(), _5 = _4.skills, _6 = _5 === void 0 ? { primary: "none", secondary: "none" } : _5, _7 = _6.primary, primary = _7 === void 0 ? "primary" : _7, _8 = _6.secondary, secondary = _8 === void 0 ? "secondary" : _8, _4, i = 0; i < 1; i++) {
+>>>for (_4 = getMultiRobot(), (_5 = _4.skills, _6 = _5 === void 0 ? { primary: "none", secondary: "none" } : _5, _7 = _6.primary, primary = _7 === void 0 ? "primary" : _7, _8 = _6.secondary, secondary = _8 === void 0 ? "secondary" : _8, _4), _4, i = 0; i < 1; i++) {
 1->
 2 >^^^
 3 >   ^
 4 >    ^
 5 >     ^^^^^^^^^^^^^^^^^^^^
-6 >                         ^^
-7 >                           ^^^^^^^^^^^^^^
-8 >                                         ^^
-9 >                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-10>                                                                                                           ^^
-11>                                                                                                             ^^^^^^^^^^^^^^^
-12>                                                                                                                            ^^
-13>                                                                                                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-14>                                                                                                                                                                      ^^
-15>                                                                                                                                                                        ^^^^^^^^^^^^^^^^^
-16>                                                                                                                                                                                         ^^
-17>                                                                                                                                                                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-18>                                                                                                                                                                                                                                       ^^^^^^
-19>                                                                                                                                                                                                                                             ^
-20>                                                                                                                                                                                                                                              ^^^
-21>                                                                                                                                                                                                                                                 ^
-22>                                                                                                                                                                                                                                                  ^^
-23>                                                                                                                                                                                                                                                    ^
-24>                                                                                                                                                                                                                                                     ^^^
-25>                                                                                                                                                                                                                                                        ^
-26>                                                                                                                                                                                                                                                         ^^
-27>                                                                                                                                                                                                                                                           ^
-28>                                                                                                                                                                                                                                                            ^^
-29>                                                                                                                                                                                                                                                              ^^
-30>                                                                                                                                                                                                                                                                ^
+6 >                         ^^^
+7 >                            ^^^^^^^^^^^^^^
+8 >                                          ^^
+9 >                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+10>                                                                                                            ^^
+11>                                                                                                              ^^^^^^^^^^^^^^^
+12>                                                                                                                             ^^
+13>                                                                                                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+14>                                                                                                                                                                       ^^
+15>                                                                                                                                                                         ^^^^^^^^^^^^^^^^^
+16>                                                                                                                                                                                          ^^
+17>                                                                                                                                                                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+18>                                                                                                                                                                                                                                        ^^^^^^^^^^^
+19>                                                                                                                                                                                                                                                   ^
+20>                                                                                                                                                                                                                                                    ^^^
+21>                                                                                                                                                                                                                                                       ^
+22>                                                                                                                                                                                                                                                        ^^
+23>                                                                                                                                                                                                                                                          ^
+24>                                                                                                                                                                                                                                                           ^^^
+25>                                                                                                                                                                                                                                                              ^
+26>                                                                                                                                                                                                                                                               ^^
+27>                                                                                                                                                                                                                                                                 ^
+28>                                                                                                                                                                                                                                                                  ^^
+29>                                                                                                                                                                                                                                                                    ^^
+30>                                                                                                                                                                                                                                                                      ^
 1->
   >
 2 >for
@@ -1535,69 +1547,69 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
   >         } = { primary: "none", secondary: "none" }
   >     } = getMultiRobot()
 6 >                         
-7 >                           skills: {
-  >                                   primary = "primary",
-  >                                   secondary = "secondary"
-  >                               } = { primary: "none", secondary: "none" }
-8 >                                         
-9 >                                           skills: {
-  >                                                   primary = "primary",
-  >                                                   secondary = "secondary"
-  >                                               } = { primary: "none", secondary: "none" }
-10>                                                                                                           
-11>                                                                                                             primary = "primary"
-12>                                                                                                                            
-13>                                                                                                                              primary = "primary"
-14>                                                                                                                                                                      ,
-  >                                                                                                                                                                              
-15>                                                                                                                                                                        secondary = "secondary"
-16>                                                                                                                                                                                         
-17>                                                                                                                                                                                           secondary = "secondary"
-18>                                                                                                                                                                                                                                       
-  >                                                                                                                                                                                                                                           } = { primary: "none", secondary: "none" }
-  >                                                                                                                                                                                                                                       } = getMultiRobot(), 
-19>                                                                                                                                                                                                                                             i
-20>                                                                                                                                                                                                                                               = 
-21>                                                                                                                                                                                                                                                 0
-22>                                                                                                                                                                                                                                                  ; 
-23>                                                                                                                                                                                                                                                    i
-24>                                                                                                                                                                                                                                                      < 
-25>                                                                                                                                                                                                                                                        1
-26>                                                                                                                                                                                                                                                         ; 
-27>                                                                                                                                                                                                                                                           i
-28>                                                                                                                                                                                                                                                            ++
-29>                                                                                                                                                                                                                                                              ) 
-30>                                                                                                                                                                                                                                                                {
+7 >                            skills: {
+  >                                    primary = "primary",
+  >                                    secondary = "secondary"
+  >                                } = { primary: "none", secondary: "none" }
+8 >                                          
+9 >                                            skills: {
+  >                                                    primary = "primary",
+  >                                                    secondary = "secondary"
+  >                                                } = { primary: "none", secondary: "none" }
+10>                                                                                                            
+11>                                                                                                              primary = "primary"
+12>                                                                                                                             
+13>                                                                                                                               primary = "primary"
+14>                                                                                                                                                                       ,
+  >                                                                                                                                                                               
+15>                                                                                                                                                                         secondary = "secondary"
+16>                                                                                                                                                                                          
+17>                                                                                                                                                                                            secondary = "secondary"
+18>                                                                                                                                                                                                                                        
+  >                                                                                                                                                                                                                                            } = { primary: "none", secondary: "none" }
+  >                                                                                                                                                                                                                                        } = getMultiRobot(), 
+19>                                                                                                                                                                                                                                                   i
+20>                                                                                                                                                                                                                                                     = 
+21>                                                                                                                                                                                                                                                       0
+22>                                                                                                                                                                                                                                                        ; 
+23>                                                                                                                                                                                                                                                          i
+24>                                                                                                                                                                                                                                                            < 
+25>                                                                                                                                                                                                                                                              1
+26>                                                                                                                                                                                                                                                               ; 
+27>                                                                                                                                                                                                                                                                 i
+28>                                                                                                                                                                                                                                                                  ++
+29>                                                                                                                                                                                                                                                                    ) 
+30>                                                                                                                                                                                                                                                                      {
 1->Emitted(42, 1) Source(81, 1) + SourceIndex(0)
 2 >Emitted(42, 4) Source(81, 4) + SourceIndex(0)
 3 >Emitted(42, 5) Source(81, 5) + SourceIndex(0)
 4 >Emitted(42, 6) Source(81, 6) + SourceIndex(0)
 5 >Emitted(42, 26) Source(86, 20) + SourceIndex(0)
-6 >Emitted(42, 28) Source(82, 5) + SourceIndex(0)
-7 >Emitted(42, 42) Source(85, 47) + SourceIndex(0)
-8 >Emitted(42, 44) Source(82, 5) + SourceIndex(0)
-9 >Emitted(42, 108) Source(85, 47) + SourceIndex(0)
-10>Emitted(42, 110) Source(83, 9) + SourceIndex(0)
-11>Emitted(42, 125) Source(83, 28) + SourceIndex(0)
-12>Emitted(42, 127) Source(83, 9) + SourceIndex(0)
-13>Emitted(42, 167) Source(83, 28) + SourceIndex(0)
-14>Emitted(42, 169) Source(84, 9) + SourceIndex(0)
-15>Emitted(42, 186) Source(84, 32) + SourceIndex(0)
-16>Emitted(42, 188) Source(84, 9) + SourceIndex(0)
-17>Emitted(42, 232) Source(84, 32) + SourceIndex(0)
-18>Emitted(42, 238) Source(86, 22) + SourceIndex(0)
-19>Emitted(42, 239) Source(86, 23) + SourceIndex(0)
-20>Emitted(42, 242) Source(86, 26) + SourceIndex(0)
-21>Emitted(42, 243) Source(86, 27) + SourceIndex(0)
-22>Emitted(42, 245) Source(86, 29) + SourceIndex(0)
-23>Emitted(42, 246) Source(86, 30) + SourceIndex(0)
-24>Emitted(42, 249) Source(86, 33) + SourceIndex(0)
-25>Emitted(42, 250) Source(86, 34) + SourceIndex(0)
-26>Emitted(42, 252) Source(86, 36) + SourceIndex(0)
-27>Emitted(42, 253) Source(86, 37) + SourceIndex(0)
-28>Emitted(42, 255) Source(86, 39) + SourceIndex(0)
-29>Emitted(42, 257) Source(86, 41) + SourceIndex(0)
-30>Emitted(42, 258) Source(86, 42) + SourceIndex(0)
+6 >Emitted(42, 29) Source(82, 5) + SourceIndex(0)
+7 >Emitted(42, 43) Source(85, 47) + SourceIndex(0)
+8 >Emitted(42, 45) Source(82, 5) + SourceIndex(0)
+9 >Emitted(42, 109) Source(85, 47) + SourceIndex(0)
+10>Emitted(42, 111) Source(83, 9) + SourceIndex(0)
+11>Emitted(42, 126) Source(83, 28) + SourceIndex(0)
+12>Emitted(42, 128) Source(83, 9) + SourceIndex(0)
+13>Emitted(42, 168) Source(83, 28) + SourceIndex(0)
+14>Emitted(42, 170) Source(84, 9) + SourceIndex(0)
+15>Emitted(42, 187) Source(84, 32) + SourceIndex(0)
+16>Emitted(42, 189) Source(84, 9) + SourceIndex(0)
+17>Emitted(42, 233) Source(84, 32) + SourceIndex(0)
+18>Emitted(42, 244) Source(86, 22) + SourceIndex(0)
+19>Emitted(42, 245) Source(86, 23) + SourceIndex(0)
+20>Emitted(42, 248) Source(86, 26) + SourceIndex(0)
+21>Emitted(42, 249) Source(86, 27) + SourceIndex(0)
+22>Emitted(42, 251) Source(86, 29) + SourceIndex(0)
+23>Emitted(42, 252) Source(86, 30) + SourceIndex(0)
+24>Emitted(42, 255) Source(86, 33) + SourceIndex(0)
+25>Emitted(42, 256) Source(86, 34) + SourceIndex(0)
+26>Emitted(42, 258) Source(86, 36) + SourceIndex(0)
+27>Emitted(42, 259) Source(86, 37) + SourceIndex(0)
+28>Emitted(42, 261) Source(86, 39) + SourceIndex(0)
+29>Emitted(42, 263) Source(86, 41) + SourceIndex(0)
+30>Emitted(42, 264) Source(86, 42) + SourceIndex(0)
 ---
 >>>    console.log(primaryA);
 1 >^^^^
@@ -1629,31 +1641,31 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(44, 1) Source(88, 1) + SourceIndex(0)
 2 >Emitted(44, 2) Source(88, 2) + SourceIndex(0)
 ---
->>>for (_9 = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, _10 = _9.skills, _11 = _10 === void 0 ? { primary: "none", secondary: "none" } : _10, _12 = _11.primary, primary = _12 === void 0 ? "primary" : _12, _13 = _11.secondary, secondary = _13 === void 0 ? "secondary" : _13, _9,
+>>>for (_9 = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, (_10 = _9.skills, _11 = _10 === void 0 ? { primary: "none", secondary: "none" } : _10, _12 = _11.primary, primary = _12 === void 0 ? "primary" : _12, _13 = _11.secondary, secondary = _13 === void 0 ? "secondary" : _13, _9), _9,
 1->
 2 >^^^
 3 >   ^
 4 >    ^
 5 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-6 >                                                                                   ^^
-7 >                                                                                     ^^^^^^^^^^^^^^^
-8 >                                                                                                    ^^
-9 >                                                                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-10>                                                                                                                                                                         ^^
-11>                                                                                                                                                                           ^^^^^^^^^^^^^^^^^
-12>                                                                                                                                                                                            ^^
-13>                                                                                                                                                                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-14>                                                                                                                                                                                                                                        ^^
-15>                                                                                                                                                                                                                                          ^^^^^^^^^^^^^^^^^^^
-16>                                                                                                                                                                                                                                                             ^^
-17>                                                                                                                                                                                                                                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+6 >                                                                                   ^^^
+7 >                                                                                      ^^^^^^^^^^^^^^^
+8 >                                                                                                     ^^
+9 >                                                                                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+10>                                                                                                                                                                          ^^
+11>                                                                                                                                                                            ^^^^^^^^^^^^^^^^^
+12>                                                                                                                                                                                             ^^
+13>                                                                                                                                                                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+14>                                                                                                                                                                                                                                         ^^
+15>                                                                                                                                                                                                                                           ^^^^^^^^^^^^^^^^^^^
+16>                                                                                                                                                                                                                                                              ^^
+17>                                                                                                                                                                                                                                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 1->
   >
 2 >for
@@ -1666,41 +1678,41 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
   >         } = { primary: "none", secondary: "none" }
   >     } = <MultiRobot>{ name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }
 6 >                                                                                   
-7 >                                                                                     skills: {
-  >                                                                                             primary = "primary",
-  >                                                                                             secondary = "secondary"
-  >                                                                                         } = { primary: "none", secondary: "none" }
-8 >                                                                                                    
-9 >                                                                                                      skills: {
-  >                                                                                                              primary = "primary",
-  >                                                                                                              secondary = "secondary"
-  >                                                                                                          } = { primary: "none", secondary: "none" }
-10>                                                                                                                                                                         
-11>                                                                                                                                                                           primary = "primary"
-12>                                                                                                                                                                                            
-13>                                                                                                                                                                                              primary = "primary"
-14>                                                                                                                                                                                                                                        ,
-  >                                                                                                                                                                                                                                                
-15>                                                                                                                                                                                                                                          secondary = "secondary"
-16>                                                                                                                                                                                                                                                             
-17>                                                                                                                                                                                                                                                               secondary = "secondary"
+7 >                                                                                      skills: {
+  >                                                                                              primary = "primary",
+  >                                                                                              secondary = "secondary"
+  >                                                                                          } = { primary: "none", secondary: "none" }
+8 >                                                                                                     
+9 >                                                                                                       skills: {
+  >                                                                                                               primary = "primary",
+  >                                                                                                               secondary = "secondary"
+  >                                                                                                           } = { primary: "none", secondary: "none" }
+10>                                                                                                                                                                          
+11>                                                                                                                                                                            primary = "primary"
+12>                                                                                                                                                                                             
+13>                                                                                                                                                                                               primary = "primary"
+14>                                                                                                                                                                                                                                         ,
+  >                                                                                                                                                                                                                                                 
+15>                                                                                                                                                                                                                                           secondary = "secondary"
+16>                                                                                                                                                                                                                                                              
+17>                                                                                                                                                                                                                                                                secondary = "secondary"
 1->Emitted(45, 1) Source(89, 1) + SourceIndex(0)
 2 >Emitted(45, 4) Source(89, 4) + SourceIndex(0)
 3 >Emitted(45, 5) Source(89, 5) + SourceIndex(0)
 4 >Emitted(45, 6) Source(89, 6) + SourceIndex(0)
 5 >Emitted(45, 84) Source(94, 90) + SourceIndex(0)
-6 >Emitted(45, 86) Source(90, 5) + SourceIndex(0)
-7 >Emitted(45, 101) Source(93, 47) + SourceIndex(0)
-8 >Emitted(45, 103) Source(90, 5) + SourceIndex(0)
-9 >Emitted(45, 170) Source(93, 47) + SourceIndex(0)
-10>Emitted(45, 172) Source(91, 9) + SourceIndex(0)
-11>Emitted(45, 189) Source(91, 28) + SourceIndex(0)
-12>Emitted(45, 191) Source(91, 9) + SourceIndex(0)
-13>Emitted(45, 233) Source(91, 28) + SourceIndex(0)
-14>Emitted(45, 235) Source(92, 9) + SourceIndex(0)
-15>Emitted(45, 254) Source(92, 32) + SourceIndex(0)
-16>Emitted(45, 256) Source(92, 9) + SourceIndex(0)
-17>Emitted(45, 302) Source(92, 32) + SourceIndex(0)
+6 >Emitted(45, 87) Source(90, 5) + SourceIndex(0)
+7 >Emitted(45, 102) Source(93, 47) + SourceIndex(0)
+8 >Emitted(45, 104) Source(90, 5) + SourceIndex(0)
+9 >Emitted(45, 171) Source(93, 47) + SourceIndex(0)
+10>Emitted(45, 173) Source(91, 9) + SourceIndex(0)
+11>Emitted(45, 190) Source(91, 28) + SourceIndex(0)
+12>Emitted(45, 192) Source(91, 9) + SourceIndex(0)
+13>Emitted(45, 234) Source(91, 28) + SourceIndex(0)
+14>Emitted(45, 236) Source(92, 9) + SourceIndex(0)
+15>Emitted(45, 255) Source(92, 32) + SourceIndex(0)
+16>Emitted(45, 257) Source(92, 9) + SourceIndex(0)
+17>Emitted(45, 303) Source(92, 32) + SourceIndex(0)
 ---
 >>>    i = 0; i < 1; i++) {
 1 >^^^^
@@ -2133,14 +2145,14 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(57, 1) Source(108, 1) + SourceIndex(0)
 2 >Emitted(57, 2) Source(108, 2) + SourceIndex(0)
 ---
->>>for (_22 = multiRobot.name, nameA = _22 === void 0 ? "noName" : _22, _23 = multiRobot.skills, _24 = _23 === void 0 ? { primary: "none", secondary: "none" } : _23, _25 = _24.primary, primaryA = _25 === void 0 ? "primary" : _25, _26 = _24.secondary, secondaryA = _26 === void 0 ? "secondary" : _26, multiRobot, i = 0; i < 1; i++) {
+>>>for (_22 = multiRobot.name, nameA = _22 === void 0 ? "noName" : _22, _23 = multiRobot.skills, _24 = _23 === void 0 ? { primary: "none", secondary: "none" } : _23, _25 = _24.primary, primaryA = _25 === void 0 ? "primary" : _25, _26 = _24.secondary, secondaryA = _26 === void 0 ? "secondary" : _26, multiRobot, multiRobot, i = 0; i < 1; i++) {
 1->
 2 >^^^
 3 >   ^
@@ -2163,18 +2175,20 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 20>                                                                                                                                                                                                                                                                                                       ^^
 21>                                                                                                                                                                                                                                                                                                         ^^^^^^^^^^
 22>                                                                                                                                                                                                                                                                                                                   ^^
-23>                                                                                                                                                                                                                                                                                                                     ^
-24>                                                                                                                                                                                                                                                                                                                      ^^^
-25>                                                                                                                                                                                                                                                                                                                         ^
-26>                                                                                                                                                                                                                                                                                                                          ^^
-27>                                                                                                                                                                                                                                                                                                                            ^
-28>                                                                                                                                                                                                                                                                                                                             ^^^
-29>                                                                                                                                                                                                                                                                                                                                ^
-30>                                                                                                                                                                                                                                                                                                                                 ^^
-31>                                                                                                                                                                                                                                                                                                                                   ^
-32>                                                                                                                                                                                                                                                                                                                                    ^^
-33>                                                                                                                                                                                                                                                                                                                                      ^^
-34>                                                                                                                                                                                                                                                                                                                                        ^
+23>                                                                                                                                                                                                                                                                                                                     ^^^^^^^^^^
+24>                                                                                                                                                                                                                                                                                                                               ^^
+25>                                                                                                                                                                                                                                                                                                                                 ^
+26>                                                                                                                                                                                                                                                                                                                                  ^^^
+27>                                                                                                                                                                                                                                                                                                                                     ^
+28>                                                                                                                                                                                                                                                                                                                                      ^^
+29>                                                                                                                                                                                                                                                                                                                                        ^
+30>                                                                                                                                                                                                                                                                                                                                         ^^^
+31>                                                                                                                                                                                                                                                                                                                                            ^
+32>                                                                                                                                                                                                                                                                                                                                             ^^
+33>                                                                                                                                                                                                                                                                                                                                               ^
+34>                                                                                                                                                                                                                                                                                                                                                ^^
+35>                                                                                                                                                                                                                                                                                                                                                  ^^
+36>                                                                                                                                                                                                                                                                                                                                                    ^
 1->
   >
 2 >for
@@ -2208,19 +2222,21 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
   >                                                                                                                                                                                                                                                                                                           } = { primary: "none", secondary: "none" }
   >                                                                                                                                                                                                                                                                                                       } = 
 21>                                                                                                                                                                                                                                                                                                         multiRobot
-22>                                                                                                                                                                                                                                                                                                                   , 
-23>                                                                                                                                                                                                                                                                                                                     i
-24>                                                                                                                                                                                                                                                                                                                       = 
-25>                                                                                                                                                                                                                                                                                                                         0
-26>                                                                                                                                                                                                                                                                                                                          ; 
-27>                                                                                                                                                                                                                                                                                                                            i
-28>                                                                                                                                                                                                                                                                                                                              < 
-29>                                                                                                                                                                                                                                                                                                                                1
-30>                                                                                                                                                                                                                                                                                                                                 ; 
-31>                                                                                                                                                                                                                                                                                                                                   i
-32>                                                                                                                                                                                                                                                                                                                                    ++
-33>                                                                                                                                                                                                                                                                                                                                      ) 
-34>                                                                                                                                                                                                                                                                                                                                        {
+22>                                                                                                                                                                                                                                                                                                                   
+23>                                                                                                                                                                                                                                                                                                                     multiRobot
+24>                                                                                                                                                                                                                                                                                                                               , 
+25>                                                                                                                                                                                                                                                                                                                                 i
+26>                                                                                                                                                                                                                                                                                                                                   = 
+27>                                                                                                                                                                                                                                                                                                                                     0
+28>                                                                                                                                                                                                                                                                                                                                      ; 
+29>                                                                                                                                                                                                                                                                                                                                        i
+30>                                                                                                                                                                                                                                                                                                                                          < 
+31>                                                                                                                                                                                                                                                                                                                                            1
+32>                                                                                                                                                                                                                                                                                                                                             ; 
+33>                                                                                                                                                                                                                                                                                                                                               i
+34>                                                                                                                                                                                                                                                                                                                                                ++
+35>                                                                                                                                                                                                                                                                                                                                                  ) 
+36>                                                                                                                                                                                                                                                                                                                                                    {
 1->Emitted(58, 1) Source(109, 1) + SourceIndex(0)
 2 >Emitted(58, 4) Source(109, 4) + SourceIndex(0)
 3 >Emitted(58, 5) Source(109, 5) + SourceIndex(0)
@@ -2242,19 +2258,21 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 19>Emitted(58, 296) Source(113, 44) + SourceIndex(0)
 20>Emitted(58, 298) Source(115, 5) + SourceIndex(0)
 21>Emitted(58, 308) Source(115, 15) + SourceIndex(0)
-22>Emitted(58, 310) Source(115, 17) + SourceIndex(0)
-23>Emitted(58, 311) Source(115, 18) + SourceIndex(0)
-24>Emitted(58, 314) Source(115, 21) + SourceIndex(0)
-25>Emitted(58, 315) Source(115, 22) + SourceIndex(0)
-26>Emitted(58, 317) Source(115, 24) + SourceIndex(0)
-27>Emitted(58, 318) Source(115, 25) + SourceIndex(0)
-28>Emitted(58, 321) Source(115, 28) + SourceIndex(0)
-29>Emitted(58, 322) Source(115, 29) + SourceIndex(0)
-30>Emitted(58, 324) Source(115, 31) + SourceIndex(0)
-31>Emitted(58, 325) Source(115, 32) + SourceIndex(0)
-32>Emitted(58, 327) Source(115, 34) + SourceIndex(0)
-33>Emitted(58, 329) Source(115, 36) + SourceIndex(0)
-34>Emitted(58, 330) Source(115, 37) + SourceIndex(0)
+22>Emitted(58, 310) Source(115, 5) + SourceIndex(0)
+23>Emitted(58, 320) Source(115, 15) + SourceIndex(0)
+24>Emitted(58, 322) Source(115, 17) + SourceIndex(0)
+25>Emitted(58, 323) Source(115, 18) + SourceIndex(0)
+26>Emitted(58, 326) Source(115, 21) + SourceIndex(0)
+27>Emitted(58, 327) Source(115, 22) + SourceIndex(0)
+28>Emitted(58, 329) Source(115, 24) + SourceIndex(0)
+29>Emitted(58, 330) Source(115, 25) + SourceIndex(0)
+30>Emitted(58, 333) Source(115, 28) + SourceIndex(0)
+31>Emitted(58, 334) Source(115, 29) + SourceIndex(0)
+32>Emitted(58, 336) Source(115, 31) + SourceIndex(0)
+33>Emitted(58, 337) Source(115, 32) + SourceIndex(0)
+34>Emitted(58, 339) Source(115, 34) + SourceIndex(0)
+35>Emitted(58, 341) Source(115, 36) + SourceIndex(0)
+36>Emitted(58, 342) Source(115, 37) + SourceIndex(0)
 ---
 >>>    console.log(primaryA);
 1 >^^^^
@@ -2286,48 +2304,48 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(60, 1) Source(117, 1) + SourceIndex(0)
 2 >Emitted(60, 2) Source(117, 2) + SourceIndex(0)
 ---
->>>for (_27 = getMultiRobot(), _28 = _27.name, nameA = _28 === void 0 ? "noName" : _28, _29 = _27.skills, _30 = _29 === void 0 ? { primary: "none", secondary: "none" } : _29, _31 = _30.primary, primaryA = _31 === void 0 ? "primary" : _31, _32 = _30.secondary, secondaryA = _32 === void 0 ? "secondary" : _32, _27, i = 0; i < 1; i++) {
+>>>for (_27 = getMultiRobot(), (_28 = _27.name, nameA = _28 === void 0 ? "noName" : _28, _29 = _27.skills, _30 = _29 === void 0 ? { primary: "none", secondary: "none" } : _29, _31 = _30.primary, primaryA = _31 === void 0 ? "primary" : _31, _32 = _30.secondary, secondaryA = _32 === void 0 ? "secondary" : _32, _27), _27, i = 0; i < 1; i++) {
 1->
 2 >^^^
 3 >   ^
 4 >    ^
 5 >     ^^^^^^^^^^^^^^^^^^^^^
-6 >                          ^^
-7 >                            ^^^^^^^^^^^^^^
-8 >                                          ^^
-9 >                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-10>                                                                                   ^^
-11>                                                                                     ^^^^^^^^^^^^^^^^
-12>                                                                                                     ^^
-13>                                                                                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-14>                                                                                                                                                                          ^^
-15>                                                                                                                                                                            ^^^^^^^^^^^^^^^^^
-16>                                                                                                                                                                                             ^^
-17>                                                                                                                                                                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-18>                                                                                                                                                                                                                                          ^^
-19>                                                                                                                                                                                                                                            ^^^^^^^^^^^^^^^^^^^
-20>                                                                                                                                                                                                                                                               ^^
-21>                                                                                                                                                                                                                                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-22>                                                                                                                                                                                                                                                                                                                ^^^^^^^
-23>                                                                                                                                                                                                                                                                                                                       ^
-24>                                                                                                                                                                                                                                                                                                                        ^^^
-25>                                                                                                                                                                                                                                                                                                                           ^
-26>                                                                                                                                                                                                                                                                                                                            ^^
-27>                                                                                                                                                                                                                                                                                                                              ^
-28>                                                                                                                                                                                                                                                                                                                               ^^^
-29>                                                                                                                                                                                                                                                                                                                                  ^
-30>                                                                                                                                                                                                                                                                                                                                   ^^
-31>                                                                                                                                                                                                                                                                                                                                     ^
-32>                                                                                                                                                                                                                                                                                                                                      ^^
-33>                                                                                                                                                                                                                                                                                                                                        ^^
-34>                                                                                                                                                                                                                                                                                                                                          ^
+6 >                          ^^^
+7 >                             ^^^^^^^^^^^^^^
+8 >                                           ^^
+9 >                                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+10>                                                                                    ^^
+11>                                                                                      ^^^^^^^^^^^^^^^^
+12>                                                                                                      ^^
+13>                                                                                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+14>                                                                                                                                                                           ^^
+15>                                                                                                                                                                             ^^^^^^^^^^^^^^^^^
+16>                                                                                                                                                                                              ^^
+17>                                                                                                                                                                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+18>                                                                                                                                                                                                                                           ^^
+19>                                                                                                                                                                                                                                             ^^^^^^^^^^^^^^^^^^^
+20>                                                                                                                                                                                                                                                                ^^
+21>                                                                                                                                                                                                                                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+22>                                                                                                                                                                                                                                                                                                                 ^^^^^^^^^^^^^
+23>                                                                                                                                                                                                                                                                                                                              ^
+24>                                                                                                                                                                                                                                                                                                                               ^^^
+25>                                                                                                                                                                                                                                                                                                                                  ^
+26>                                                                                                                                                                                                                                                                                                                                   ^^
+27>                                                                                                                                                                                                                                                                                                                                     ^
+28>                                                                                                                                                                                                                                                                                                                                      ^^^
+29>                                                                                                                                                                                                                                                                                                                                         ^
+30>                                                                                                                                                                                                                                                                                                                                          ^^
+31>                                                                                                                                                                                                                                                                                                                                            ^
+32>                                                                                                                                                                                                                                                                                                                                             ^^
+33>                                                                                                                                                                                                                                                                                                                                               ^^
+34>                                                                                                                                                                                                                                                                                                                                                 ^
 1->
   >
 2 >for
@@ -2341,78 +2359,78 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
   >         } = { primary: "none", secondary: "none" }
   >     } = getMultiRobot()
 6 >                          
-7 >                            name: nameA = "noName"
-8 >                                          
-9 >                                            name: nameA = "noName"
-10>                                                                                   ,
-  >                                                                                       
-11>                                                                                     skills: {
-  >                                                                                             primary: primaryA = "primary",
-  >                                                                                             secondary: secondaryA = "secondary"
-  >                                                                                         } = { primary: "none", secondary: "none" }
-12>                                                                                                     
-13>                                                                                                       skills: {
-  >                                                                                                               primary: primaryA = "primary",
-  >                                                                                                               secondary: secondaryA = "secondary"
-  >                                                                                                           } = { primary: "none", secondary: "none" }
-14>                                                                                                                                                                          
-15>                                                                                                                                                                            primary: primaryA = "primary"
-16>                                                                                                                                                                                             
-17>                                                                                                                                                                                               primary: primaryA = "primary"
-18>                                                                                                                                                                                                                                          ,
-  >                                                                                                                                                                                                                                                  
-19>                                                                                                                                                                                                                                            secondary: secondaryA = "secondary"
-20>                                                                                                                                                                                                                                                               
-21>                                                                                                                                                                                                                                                                 secondary: secondaryA = "secondary"
-22>                                                                                                                                                                                                                                                                                                                
-  >                                                                                                                                                                                                                                                                                                                    } = { primary: "none", secondary: "none" }
-  >                                                                                                                                                                                                                                                                                                                } = getMultiRobot(), 
-23>                                                                                                                                                                                                                                                                                                                       i
-24>                                                                                                                                                                                                                                                                                                                         = 
-25>                                                                                                                                                                                                                                                                                                                           0
-26>                                                                                                                                                                                                                                                                                                                            ; 
-27>                                                                                                                                                                                                                                                                                                                              i
-28>                                                                                                                                                                                                                                                                                                                                < 
-29>                                                                                                                                                                                                                                                                                                                                  1
-30>                                                                                                                                                                                                                                                                                                                                   ; 
-31>                                                                                                                                                                                                                                                                                                                                     i
-32>                                                                                                                                                                                                                                                                                                                                      ++
-33>                                                                                                                                                                                                                                                                                                                                        ) 
-34>                                                                                                                                                                                                                                                                                                                                          {
+7 >                             name: nameA = "noName"
+8 >                                           
+9 >                                             name: nameA = "noName"
+10>                                                                                    ,
+  >                                                                                        
+11>                                                                                      skills: {
+  >                                                                                              primary: primaryA = "primary",
+  >                                                                                              secondary: secondaryA = "secondary"
+  >                                                                                          } = { primary: "none", secondary: "none" }
+12>                                                                                                      
+13>                                                                                                        skills: {
+  >                                                                                                                primary: primaryA = "primary",
+  >                                                                                                                secondary: secondaryA = "secondary"
+  >                                                                                                            } = { primary: "none", secondary: "none" }
+14>                                                                                                                                                                           
+15>                                                                                                                                                                             primary: primaryA = "primary"
+16>                                                                                                                                                                                              
+17>                                                                                                                                                                                                primary: primaryA = "primary"
+18>                                                                                                                                                                                                                                           ,
+  >                                                                                                                                                                                                                                                   
+19>                                                                                                                                                                                                                                             secondary: secondaryA = "secondary"
+20>                                                                                                                                                                                                                                                                
+21>                                                                                                                                                                                                                                                                  secondary: secondaryA = "secondary"
+22>                                                                                                                                                                                                                                                                                                                 
+  >                                                                                                                                                                                                                                                                                                                     } = { primary: "none", secondary: "none" }
+  >                                                                                                                                                                                                                                                                                                                 } = getMultiRobot(), 
+23>                                                                                                                                                                                                                                                                                                                              i
+24>                                                                                                                                                                                                                                                                                                                                = 
+25>                                                                                                                                                                                                                                                                                                                                  0
+26>                                                                                                                                                                                                                                                                                                                                   ; 
+27>                                                                                                                                                                                                                                                                                                                                     i
+28>                                                                                                                                                                                                                                                                                                                                       < 
+29>                                                                                                                                                                                                                                                                                                                                         1
+30>                                                                                                                                                                                                                                                                                                                                          ; 
+31>                                                                                                                                                                                                                                                                                                                                            i
+32>                                                                                                                                                                                                                                                                                                                                             ++
+33>                                                                                                                                                                                                                                                                                                                                               ) 
+34>                                                                                                                                                                                                                                                                                                                                                 {
 1->Emitted(61, 1) Source(118, 1) + SourceIndex(0)
 2 >Emitted(61, 4) Source(118, 4) + SourceIndex(0)
 3 >Emitted(61, 5) Source(118, 5) + SourceIndex(0)
 4 >Emitted(61, 6) Source(118, 6) + SourceIndex(0)
 5 >Emitted(61, 27) Source(124, 20) + SourceIndex(0)
-6 >Emitted(61, 29) Source(119, 5) + SourceIndex(0)
-7 >Emitted(61, 43) Source(119, 27) + SourceIndex(0)
-8 >Emitted(61, 45) Source(119, 5) + SourceIndex(0)
-9 >Emitted(61, 84) Source(119, 27) + SourceIndex(0)
-10>Emitted(61, 86) Source(120, 5) + SourceIndex(0)
-11>Emitted(61, 102) Source(123, 47) + SourceIndex(0)
-12>Emitted(61, 104) Source(120, 5) + SourceIndex(0)
-13>Emitted(61, 171) Source(123, 47) + SourceIndex(0)
-14>Emitted(61, 173) Source(121, 9) + SourceIndex(0)
-15>Emitted(61, 190) Source(121, 38) + SourceIndex(0)
-16>Emitted(61, 192) Source(121, 9) + SourceIndex(0)
-17>Emitted(61, 235) Source(121, 38) + SourceIndex(0)
-18>Emitted(61, 237) Source(122, 9) + SourceIndex(0)
-19>Emitted(61, 256) Source(122, 44) + SourceIndex(0)
-20>Emitted(61, 258) Source(122, 9) + SourceIndex(0)
-21>Emitted(61, 305) Source(122, 44) + SourceIndex(0)
-22>Emitted(61, 312) Source(124, 22) + SourceIndex(0)
-23>Emitted(61, 313) Source(124, 23) + SourceIndex(0)
-24>Emitted(61, 316) Source(124, 26) + SourceIndex(0)
-25>Emitted(61, 317) Source(124, 27) + SourceIndex(0)
-26>Emitted(61, 319) Source(124, 29) + SourceIndex(0)
-27>Emitted(61, 320) Source(124, 30) + SourceIndex(0)
-28>Emitted(61, 323) Source(124, 33) + SourceIndex(0)
-29>Emitted(61, 324) Source(124, 34) + SourceIndex(0)
-30>Emitted(61, 326) Source(124, 36) + SourceIndex(0)
-31>Emitted(61, 327) Source(124, 37) + SourceIndex(0)
-32>Emitted(61, 329) Source(124, 39) + SourceIndex(0)
-33>Emitted(61, 331) Source(124, 41) + SourceIndex(0)
-34>Emitted(61, 332) Source(124, 42) + SourceIndex(0)
+6 >Emitted(61, 30) Source(119, 5) + SourceIndex(0)
+7 >Emitted(61, 44) Source(119, 27) + SourceIndex(0)
+8 >Emitted(61, 46) Source(119, 5) + SourceIndex(0)
+9 >Emitted(61, 85) Source(119, 27) + SourceIndex(0)
+10>Emitted(61, 87) Source(120, 5) + SourceIndex(0)
+11>Emitted(61, 103) Source(123, 47) + SourceIndex(0)
+12>Emitted(61, 105) Source(120, 5) + SourceIndex(0)
+13>Emitted(61, 172) Source(123, 47) + SourceIndex(0)
+14>Emitted(61, 174) Source(121, 9) + SourceIndex(0)
+15>Emitted(61, 191) Source(121, 38) + SourceIndex(0)
+16>Emitted(61, 193) Source(121, 9) + SourceIndex(0)
+17>Emitted(61, 236) Source(121, 38) + SourceIndex(0)
+18>Emitted(61, 238) Source(122, 9) + SourceIndex(0)
+19>Emitted(61, 257) Source(122, 44) + SourceIndex(0)
+20>Emitted(61, 259) Source(122, 9) + SourceIndex(0)
+21>Emitted(61, 306) Source(122, 44) + SourceIndex(0)
+22>Emitted(61, 319) Source(124, 22) + SourceIndex(0)
+23>Emitted(61, 320) Source(124, 23) + SourceIndex(0)
+24>Emitted(61, 323) Source(124, 26) + SourceIndex(0)
+25>Emitted(61, 324) Source(124, 27) + SourceIndex(0)
+26>Emitted(61, 326) Source(124, 29) + SourceIndex(0)
+27>Emitted(61, 327) Source(124, 30) + SourceIndex(0)
+28>Emitted(61, 330) Source(124, 33) + SourceIndex(0)
+29>Emitted(61, 331) Source(124, 34) + SourceIndex(0)
+30>Emitted(61, 333) Source(124, 36) + SourceIndex(0)
+31>Emitted(61, 334) Source(124, 37) + SourceIndex(0)
+32>Emitted(61, 336) Source(124, 39) + SourceIndex(0)
+33>Emitted(61, 338) Source(124, 41) + SourceIndex(0)
+34>Emitted(61, 339) Source(124, 42) + SourceIndex(0)
 ---
 >>>    console.log(primaryA);
 1 >^^^^
@@ -2444,35 +2462,35 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(63, 1) Source(126, 1) + SourceIndex(0)
 2 >Emitted(63, 2) Source(126, 2) + SourceIndex(0)
 ---
->>>for (_33 = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, _34 = _33.name, nameA = _34 === void 0 ? "noName" : _34, _35 = _33.skills, _36 = _35 === void 0 ? { primary: "none", secondary: "none" } : _35, _37 = _36.primary, primaryA = _37 === void 0 ? "primary" : _37, _38 = _36.secondary, secondaryA = _38 === void 0 ? "secondary" : _38, _33,
+>>>for (_33 = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, (_34 = _33.name, nameA = _34 === void 0 ? "noName" : _34, _35 = _33.skills, _36 = _35 === void 0 ? { primary: "none", secondary: "none" } : _35, _37 = _36.primary, primaryA = _37 === void 0 ? "primary" : _37, _38 = _36.secondary, secondaryA = _38 === void 0 ? "secondary" : _38, _33), _33,
 1->
 2 >^^^
 3 >   ^
 4 >    ^
 5 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-6 >                                                                                    ^^
-7 >                                                                                      ^^^^^^^^^^^^^^
-8 >                                                                                                    ^^
-9 >                                                                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-10>                                                                                                                                             ^^
-11>                                                                                                                                               ^^^^^^^^^^^^^^^^
-12>                                                                                                                                                               ^^
-13>                                                                                                                                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-14>                                                                                                                                                                                                                                    ^^
-15>                                                                                                                                                                                                                                      ^^^^^^^^^^^^^^^^^
-16>                                                                                                                                                                                                                                                       ^^
-17>                                                                                                                                                                                                                                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-18>                                                                                                                                                                                                                                                                                                    ^^
-19>                                                                                                                                                                                                                                                                                                      ^^^^^^^^^^^^^^^^^^^
-20>                                                                                                                                                                                                                                                                                                                         ^^
-21>                                                                                                                                                                                                                                                                                                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+6 >                                                                                    ^^^
+7 >                                                                                       ^^^^^^^^^^^^^^
+8 >                                                                                                     ^^
+9 >                                                                                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+10>                                                                                                                                              ^^
+11>                                                                                                                                                ^^^^^^^^^^^^^^^^
+12>                                                                                                                                                                ^^
+13>                                                                                                                                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+14>                                                                                                                                                                                                                                     ^^
+15>                                                                                                                                                                                                                                       ^^^^^^^^^^^^^^^^^
+16>                                                                                                                                                                                                                                                        ^^
+17>                                                                                                                                                                                                                                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+18>                                                                                                                                                                                                                                                                                                     ^^
+19>                                                                                                                                                                                                                                                                                                       ^^^^^^^^^^^^^^^^^^^
+20>                                                                                                                                                                                                                                                                                                                          ^^
+21>                                                                                                                                                                                                                                                                                                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 1->
   >
 2 >for
@@ -2486,50 +2504,50 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
   >         } = { primary: "none", secondary: "none" }
   >     } = <MultiRobot>{ name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }
 6 >                                                                                    
-7 >                                                                                      name: nameA = "noName"
-8 >                                                                                                    
-9 >                                                                                                      name: nameA = "noName"
-10>                                                                                                                                             ,
-  >                                                                                                                                                 
-11>                                                                                                                                               skills: {
-  >                                                                                                                                                       primary: primaryA = "primary",
-  >                                                                                                                                                       secondary: secondaryA = "secondary"
-  >                                                                                                                                                   } = { primary: "none", secondary: "none" }
-12>                                                                                                                                                               
-13>                                                                                                                                                                 skills: {
-  >                                                                                                                                                                         primary: primaryA = "primary",
-  >                                                                                                                                                                         secondary: secondaryA = "secondary"
-  >                                                                                                                                                                     } = { primary: "none", secondary: "none" }
-14>                                                                                                                                                                                                                                    
-15>                                                                                                                                                                                                                                      primary: primaryA = "primary"
-16>                                                                                                                                                                                                                                                       
-17>                                                                                                                                                                                                                                                         primary: primaryA = "primary"
-18>                                                                                                                                                                                                                                                                                                    ,
-  >                                                                                                                                                                                                                                                                                                            
-19>                                                                                                                                                                                                                                                                                                      secondary: secondaryA = "secondary"
-20>                                                                                                                                                                                                                                                                                                                         
-21>                                                                                                                                                                                                                                                                                                                           secondary: secondaryA = "secondary"
+7 >                                                                                       name: nameA = "noName"
+8 >                                                                                                     
+9 >                                                                                                       name: nameA = "noName"
+10>                                                                                                                                              ,
+  >                                                                                                                                                  
+11>                                                                                                                                                skills: {
+  >                                                                                                                                                        primary: primaryA = "primary",
+  >                                                                                                                                                        secondary: secondaryA = "secondary"
+  >                                                                                                                                                    } = { primary: "none", secondary: "none" }
+12>                                                                                                                                                                
+13>                                                                                                                                                                  skills: {
+  >                                                                                                                                                                          primary: primaryA = "primary",
+  >                                                                                                                                                                          secondary: secondaryA = "secondary"
+  >                                                                                                                                                                      } = { primary: "none", secondary: "none" }
+14>                                                                                                                                                                                                                                     
+15>                                                                                                                                                                                                                                       primary: primaryA = "primary"
+16>                                                                                                                                                                                                                                                        
+17>                                                                                                                                                                                                                                                          primary: primaryA = "primary"
+18>                                                                                                                                                                                                                                                                                                     ,
+  >                                                                                                                                                                                                                                                                                                             
+19>                                                                                                                                                                                                                                                                                                       secondary: secondaryA = "secondary"
+20>                                                                                                                                                                                                                                                                                                                          
+21>                                                                                                                                                                                                                                                                                                                            secondary: secondaryA = "secondary"
 1->Emitted(64, 1) Source(127, 1) + SourceIndex(0)
 2 >Emitted(64, 4) Source(127, 4) + SourceIndex(0)
 3 >Emitted(64, 5) Source(127, 5) + SourceIndex(0)
 4 >Emitted(64, 6) Source(127, 6) + SourceIndex(0)
 5 >Emitted(64, 85) Source(133, 90) + SourceIndex(0)
-6 >Emitted(64, 87) Source(128, 5) + SourceIndex(0)
-7 >Emitted(64, 101) Source(128, 27) + SourceIndex(0)
-8 >Emitted(64, 103) Source(128, 5) + SourceIndex(0)
-9 >Emitted(64, 142) Source(128, 27) + SourceIndex(0)
-10>Emitted(64, 144) Source(129, 5) + SourceIndex(0)
-11>Emitted(64, 160) Source(132, 47) + SourceIndex(0)
-12>Emitted(64, 162) Source(129, 5) + SourceIndex(0)
-13>Emitted(64, 229) Source(132, 47) + SourceIndex(0)
-14>Emitted(64, 231) Source(130, 9) + SourceIndex(0)
-15>Emitted(64, 248) Source(130, 38) + SourceIndex(0)
-16>Emitted(64, 250) Source(130, 9) + SourceIndex(0)
-17>Emitted(64, 293) Source(130, 38) + SourceIndex(0)
-18>Emitted(64, 295) Source(131, 9) + SourceIndex(0)
-19>Emitted(64, 314) Source(131, 44) + SourceIndex(0)
-20>Emitted(64, 316) Source(131, 9) + SourceIndex(0)
-21>Emitted(64, 363) Source(131, 44) + SourceIndex(0)
+6 >Emitted(64, 88) Source(128, 5) + SourceIndex(0)
+7 >Emitted(64, 102) Source(128, 27) + SourceIndex(0)
+8 >Emitted(64, 104) Source(128, 5) + SourceIndex(0)
+9 >Emitted(64, 143) Source(128, 27) + SourceIndex(0)
+10>Emitted(64, 145) Source(129, 5) + SourceIndex(0)
+11>Emitted(64, 161) Source(132, 47) + SourceIndex(0)
+12>Emitted(64, 163) Source(129, 5) + SourceIndex(0)
+13>Emitted(64, 230) Source(132, 47) + SourceIndex(0)
+14>Emitted(64, 232) Source(130, 9) + SourceIndex(0)
+15>Emitted(64, 249) Source(130, 38) + SourceIndex(0)
+16>Emitted(64, 251) Source(130, 9) + SourceIndex(0)
+17>Emitted(64, 294) Source(130, 38) + SourceIndex(0)
+18>Emitted(64, 296) Source(131, 9) + SourceIndex(0)
+19>Emitted(64, 315) Source(131, 44) + SourceIndex(0)
+20>Emitted(64, 317) Source(131, 9) + SourceIndex(0)
+21>Emitted(64, 364) Source(131, 44) + SourceIndex(0)
 ---
 >>>    i = 0; i < 1; i++) {
 1 >^^^^
@@ -2961,14 +2979,14 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(76, 1) Source(146, 1) + SourceIndex(0)
 2 >Emitted(76, 2) Source(146, 2) + SourceIndex(0)
 ---
->>>for (_47 = multiRobot.name, name = _47 === void 0 ? "noName" : _47, _48 = multiRobot.skills, _49 = _48 === void 0 ? { primary: "none", secondary: "none" } : _48, _50 = _49.primary, primary = _50 === void 0 ? "primary" : _50, _51 = _49.secondary, secondary = _51 === void 0 ? "secondary" : _51, multiRobot, i = 0; i < 1; i++) {
+>>>for (_47 = multiRobot.name, name = _47 === void 0 ? "noName" : _47, _48 = multiRobot.skills, _49 = _48 === void 0 ? { primary: "none", secondary: "none" } : _48, _50 = _49.primary, primary = _50 === void 0 ? "primary" : _50, _51 = _49.secondary, secondary = _51 === void 0 ? "secondary" : _51, multiRobot, multiRobot, i = 0; i < 1; i++) {
 1->
 2 >^^^
 3 >   ^
@@ -2991,18 +3009,20 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 20>                                                                                                                                                                                                                                                                                                    ^^
 21>                                                                                                                                                                                                                                                                                                      ^^^^^^^^^^
 22>                                                                                                                                                                                                                                                                                                                ^^
-23>                                                                                                                                                                                                                                                                                                                  ^
-24>                                                                                                                                                                                                                                                                                                                   ^^^
-25>                                                                                                                                                                                                                                                                                                                      ^
-26>                                                                                                                                                                                                                                                                                                                       ^^
-27>                                                                                                                                                                                                                                                                                                                         ^
-28>                                                                                                                                                                                                                                                                                                                          ^^^
-29>                                                                                                                                                                                                                                                                                                                             ^
-30>                                                                                                                                                                                                                                                                                                                              ^^
-31>                                                                                                                                                                                                                                                                                                                                ^
-32>                                                                                                                                                                                                                                                                                                                                 ^^
-33>                                                                                                                                                                                                                                                                                                                                   ^^
-34>                                                                                                                                                                                                                                                                                                                                     ^
+23>                                                                                                                                                                                                                                                                                                                  ^^^^^^^^^^
+24>                                                                                                                                                                                                                                                                                                                            ^^
+25>                                                                                                                                                                                                                                                                                                                              ^
+26>                                                                                                                                                                                                                                                                                                                               ^^^
+27>                                                                                                                                                                                                                                                                                                                                  ^
+28>                                                                                                                                                                                                                                                                                                                                   ^^
+29>                                                                                                                                                                                                                                                                                                                                     ^
+30>                                                                                                                                                                                                                                                                                                                                      ^^^
+31>                                                                                                                                                                                                                                                                                                                                         ^
+32>                                                                                                                                                                                                                                                                                                                                          ^^
+33>                                                                                                                                                                                                                                                                                                                                            ^
+34>                                                                                                                                                                                                                                                                                                                                             ^^
+35>                                                                                                                                                                                                                                                                                                                                               ^^
+36>                                                                                                                                                                                                                                                                                                                                                 ^
 1->
   >
 2 >for
@@ -3036,19 +3056,21 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
   >                                                                                                                                                                                                                                                                                                        } = { primary: "none", secondary: "none" }
   >                                                                                                                                                                                                                                                                                                    } = 
 21>                                                                                                                                                                                                                                                                                                      multiRobot
-22>                                                                                                                                                                                                                                                                                                                , 
-23>                                                                                                                                                                                                                                                                                                                  i
-24>                                                                                                                                                                                                                                                                                                                    = 
-25>                                                                                                                                                                                                                                                                                                                      0
-26>                                                                                                                                                                                                                                                                                                                       ; 
-27>                                                                                                                                                                                                                                                                                                                         i
-28>                                                                                                                                                                                                                                                                                                                           < 
-29>                                                                                                                                                                                                                                                                                                                             1
-30>                                                                                                                                                                                                                                                                                                                              ; 
-31>                                                                                                                                                                                                                                                                                                                                i
-32>                                                                                                                                                                                                                                                                                                                                 ++
-33>                                                                                                                                                                                                                                                                                                                                   ) 
-34>                                                                                                                                                                                                                                                                                                                                     {
+22>                                                                                                                                                                                                                                                                                                                
+23>                                                                                                                                                                                                                                                                                                                  multiRobot
+24>                                                                                                                                                                                                                                                                                                                            , 
+25>                                                                                                                                                                                                                                                                                                                              i
+26>                                                                                                                                                                                                                                                                                                                                = 
+27>                                                                                                                                                                                                                                                                                                                                  0
+28>                                                                                                                                                                                                                                                                                                                                   ; 
+29>                                                                                                                                                                                                                                                                                                                                     i
+30>                                                                                                                                                                                                                                                                                                                                       < 
+31>                                                                                                                                                                                                                                                                                                                                         1
+32>                                                                                                                                                                                                                                                                                                                                          ; 
+33>                                                                                                                                                                                                                                                                                                                                            i
+34>                                                                                                                                                                                                                                                                                                                                             ++
+35>                                                                                                                                                                                                                                                                                                                                               ) 
+36>                                                                                                                                                                                                                                                                                                                                                 {
 1->Emitted(77, 1) Source(147, 1) + SourceIndex(0)
 2 >Emitted(77, 4) Source(147, 4) + SourceIndex(0)
 3 >Emitted(77, 5) Source(147, 5) + SourceIndex(0)
@@ -3070,19 +3092,21 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 19>Emitted(77, 293) Source(151, 32) + SourceIndex(0)
 20>Emitted(77, 295) Source(153, 5) + SourceIndex(0)
 21>Emitted(77, 305) Source(153, 15) + SourceIndex(0)
-22>Emitted(77, 307) Source(153, 17) + SourceIndex(0)
-23>Emitted(77, 308) Source(153, 18) + SourceIndex(0)
-24>Emitted(77, 311) Source(153, 21) + SourceIndex(0)
-25>Emitted(77, 312) Source(153, 22) + SourceIndex(0)
-26>Emitted(77, 314) Source(153, 24) + SourceIndex(0)
-27>Emitted(77, 315) Source(153, 25) + SourceIndex(0)
-28>Emitted(77, 318) Source(153, 28) + SourceIndex(0)
-29>Emitted(77, 319) Source(153, 29) + SourceIndex(0)
-30>Emitted(77, 321) Source(153, 31) + SourceIndex(0)
-31>Emitted(77, 322) Source(153, 32) + SourceIndex(0)
-32>Emitted(77, 324) Source(153, 34) + SourceIndex(0)
-33>Emitted(77, 326) Source(153, 36) + SourceIndex(0)
-34>Emitted(77, 327) Source(153, 37) + SourceIndex(0)
+22>Emitted(77, 307) Source(153, 5) + SourceIndex(0)
+23>Emitted(77, 317) Source(153, 15) + SourceIndex(0)
+24>Emitted(77, 319) Source(153, 17) + SourceIndex(0)
+25>Emitted(77, 320) Source(153, 18) + SourceIndex(0)
+26>Emitted(77, 323) Source(153, 21) + SourceIndex(0)
+27>Emitted(77, 324) Source(153, 22) + SourceIndex(0)
+28>Emitted(77, 326) Source(153, 24) + SourceIndex(0)
+29>Emitted(77, 327) Source(153, 25) + SourceIndex(0)
+30>Emitted(77, 330) Source(153, 28) + SourceIndex(0)
+31>Emitted(77, 331) Source(153, 29) + SourceIndex(0)
+32>Emitted(77, 333) Source(153, 31) + SourceIndex(0)
+33>Emitted(77, 334) Source(153, 32) + SourceIndex(0)
+34>Emitted(77, 336) Source(153, 34) + SourceIndex(0)
+35>Emitted(77, 338) Source(153, 36) + SourceIndex(0)
+36>Emitted(77, 339) Source(153, 37) + SourceIndex(0)
 ---
 >>>    console.log(primaryA);
 1 >^^^^
@@ -3114,48 +3138,48 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(79, 1) Source(155, 1) + SourceIndex(0)
 2 >Emitted(79, 2) Source(155, 2) + SourceIndex(0)
 ---
->>>for (_52 = getMultiRobot(), _53 = _52.name, name = _53 === void 0 ? "noName" : _53, _54 = _52.skills, _55 = _54 === void 0 ? { primary: "none", secondary: "none" } : _54, _56 = _55.primary, primary = _56 === void 0 ? "primary" : _56, _57 = _55.secondary, secondary = _57 === void 0 ? "secondary" : _57, _52, i = 0; i < 1; i++) {
+>>>for (_52 = getMultiRobot(), (_53 = _52.name, name = _53 === void 0 ? "noName" : _53, _54 = _52.skills, _55 = _54 === void 0 ? { primary: "none", secondary: "none" } : _54, _56 = _55.primary, primary = _56 === void 0 ? "primary" : _56, _57 = _55.secondary, secondary = _57 === void 0 ? "secondary" : _57, _52), _52, i = 0; i < 1; i++) {
 1->
 2 >^^^
 3 >   ^
 4 >    ^
 5 >     ^^^^^^^^^^^^^^^^^^^^^
-6 >                          ^^
-7 >                            ^^^^^^^^^^^^^^
-8 >                                          ^^
-9 >                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-10>                                                                                  ^^
-11>                                                                                    ^^^^^^^^^^^^^^^^
-12>                                                                                                    ^^
-13>                                                                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-14>                                                                                                                                                                         ^^
-15>                                                                                                                                                                           ^^^^^^^^^^^^^^^^^
-16>                                                                                                                                                                                            ^^
-17>                                                                                                                                                                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-18>                                                                                                                                                                                                                                        ^^
-19>                                                                                                                                                                                                                                          ^^^^^^^^^^^^^^^^^^^
-20>                                                                                                                                                                                                                                                             ^^
-21>                                                                                                                                                                                                                                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-22>                                                                                                                                                                                                                                                                                                             ^^^^^^^
-23>                                                                                                                                                                                                                                                                                                                    ^
-24>                                                                                                                                                                                                                                                                                                                     ^^^
-25>                                                                                                                                                                                                                                                                                                                        ^
-26>                                                                                                                                                                                                                                                                                                                         ^^
-27>                                                                                                                                                                                                                                                                                                                           ^
-28>                                                                                                                                                                                                                                                                                                                            ^^^
-29>                                                                                                                                                                                                                                                                                                                               ^
-30>                                                                                                                                                                                                                                                                                                                                ^^
-31>                                                                                                                                                                                                                                                                                                                                  ^
-32>                                                                                                                                                                                                                                                                                                                                   ^^
-33>                                                                                                                                                                                                                                                                                                                                     ^^
-34>                                                                                                                                                                                                                                                                                                                                       ^
+6 >                          ^^^
+7 >                             ^^^^^^^^^^^^^^
+8 >                                           ^^
+9 >                                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+10>                                                                                   ^^
+11>                                                                                     ^^^^^^^^^^^^^^^^
+12>                                                                                                     ^^
+13>                                                                                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+14>                                                                                                                                                                          ^^
+15>                                                                                                                                                                            ^^^^^^^^^^^^^^^^^
+16>                                                                                                                                                                                             ^^
+17>                                                                                                                                                                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+18>                                                                                                                                                                                                                                         ^^
+19>                                                                                                                                                                                                                                           ^^^^^^^^^^^^^^^^^^^
+20>                                                                                                                                                                                                                                                              ^^
+21>                                                                                                                                                                                                                                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+22>                                                                                                                                                                                                                                                                                                              ^^^^^^^^^^^^^
+23>                                                                                                                                                                                                                                                                                                                           ^
+24>                                                                                                                                                                                                                                                                                                                            ^^^
+25>                                                                                                                                                                                                                                                                                                                               ^
+26>                                                                                                                                                                                                                                                                                                                                ^^
+27>                                                                                                                                                                                                                                                                                                                                  ^
+28>                                                                                                                                                                                                                                                                                                                                   ^^^
+29>                                                                                                                                                                                                                                                                                                                                      ^
+30>                                                                                                                                                                                                                                                                                                                                       ^^
+31>                                                                                                                                                                                                                                                                                                                                         ^
+32>                                                                                                                                                                                                                                                                                                                                          ^^
+33>                                                                                                                                                                                                                                                                                                                                            ^^
+34>                                                                                                                                                                                                                                                                                                                                              ^
 1->
   >
 2 >for
@@ -3169,78 +3193,78 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
   >         } = { primary: "none", secondary: "none" }
   >     } = getMultiRobot()
 6 >                          
-7 >                            name = "noName"
-8 >                                          
-9 >                                            name = "noName"
-10>                                                                                  ,
-  >                                                                                      
-11>                                                                                    skills: {
-  >                                                                                            primary = "primary",
-  >                                                                                            secondary = "secondary"
-  >                                                                                        } = { primary: "none", secondary: "none" }
-12>                                                                                                    
-13>                                                                                                      skills: {
-  >                                                                                                              primary = "primary",
-  >                                                                                                              secondary = "secondary"
-  >                                                                                                          } = { primary: "none", secondary: "none" }
-14>                                                                                                                                                                         
-15>                                                                                                                                                                           primary = "primary"
-16>                                                                                                                                                                                            
-17>                                                                                                                                                                                              primary = "primary"
-18>                                                                                                                                                                                                                                        ,
-  >                                                                                                                                                                                                                                                
-19>                                                                                                                                                                                                                                          secondary = "secondary"
-20>                                                                                                                                                                                                                                                             
-21>                                                                                                                                                                                                                                                               secondary = "secondary"
-22>                                                                                                                                                                                                                                                                                                             
-  >                                                                                                                                                                                                                                                                                                                 } = { primary: "none", secondary: "none" }
-  >                                                                                                                                                                                                                                                                                                             } = getMultiRobot(), 
-23>                                                                                                                                                                                                                                                                                                                    i
-24>                                                                                                                                                                                                                                                                                                                      = 
-25>                                                                                                                                                                                                                                                                                                                        0
-26>                                                                                                                                                                                                                                                                                                                         ; 
-27>                                                                                                                                                                                                                                                                                                                           i
-28>                                                                                                                                                                                                                                                                                                                             < 
-29>                                                                                                                                                                                                                                                                                                                               1
-30>                                                                                                                                                                                                                                                                                                                                ; 
-31>                                                                                                                                                                                                                                                                                                                                  i
-32>                                                                                                                                                                                                                                                                                                                                   ++
-33>                                                                                                                                                                                                                                                                                                                                     ) 
-34>                                                                                                                                                                                                                                                                                                                                       {
+7 >                             name = "noName"
+8 >                                           
+9 >                                             name = "noName"
+10>                                                                                   ,
+  >                                                                                       
+11>                                                                                     skills: {
+  >                                                                                             primary = "primary",
+  >                                                                                             secondary = "secondary"
+  >                                                                                         } = { primary: "none", secondary: "none" }
+12>                                                                                                     
+13>                                                                                                       skills: {
+  >                                                                                                               primary = "primary",
+  >                                                                                                               secondary = "secondary"
+  >                                                                                                           } = { primary: "none", secondary: "none" }
+14>                                                                                                                                                                          
+15>                                                                                                                                                                            primary = "primary"
+16>                                                                                                                                                                                             
+17>                                                                                                                                                                                               primary = "primary"
+18>                                                                                                                                                                                                                                         ,
+  >                                                                                                                                                                                                                                                 
+19>                                                                                                                                                                                                                                           secondary = "secondary"
+20>                                                                                                                                                                                                                                                              
+21>                                                                                                                                                                                                                                                                secondary = "secondary"
+22>                                                                                                                                                                                                                                                                                                              
+  >                                                                                                                                                                                                                                                                                                                  } = { primary: "none", secondary: "none" }
+  >                                                                                                                                                                                                                                                                                                              } = getMultiRobot(), 
+23>                                                                                                                                                                                                                                                                                                                           i
+24>                                                                                                                                                                                                                                                                                                                             = 
+25>                                                                                                                                                                                                                                                                                                                               0
+26>                                                                                                                                                                                                                                                                                                                                ; 
+27>                                                                                                                                                                                                                                                                                                                                  i
+28>                                                                                                                                                                                                                                                                                                                                    < 
+29>                                                                                                                                                                                                                                                                                                                                      1
+30>                                                                                                                                                                                                                                                                                                                                       ; 
+31>                                                                                                                                                                                                                                                                                                                                         i
+32>                                                                                                                                                                                                                                                                                                                                          ++
+33>                                                                                                                                                                                                                                                                                                                                            ) 
+34>                                                                                                                                                                                                                                                                                                                                              {
 1->Emitted(80, 1) Source(156, 1) + SourceIndex(0)
 2 >Emitted(80, 4) Source(156, 4) + SourceIndex(0)
 3 >Emitted(80, 5) Source(156, 5) + SourceIndex(0)
 4 >Emitted(80, 6) Source(156, 6) + SourceIndex(0)
 5 >Emitted(80, 27) Source(162, 20) + SourceIndex(0)
-6 >Emitted(80, 29) Source(157, 5) + SourceIndex(0)
-7 >Emitted(80, 43) Source(157, 20) + SourceIndex(0)
-8 >Emitted(80, 45) Source(157, 5) + SourceIndex(0)
-9 >Emitted(80, 83) Source(157, 20) + SourceIndex(0)
-10>Emitted(80, 85) Source(158, 5) + SourceIndex(0)
-11>Emitted(80, 101) Source(161, 47) + SourceIndex(0)
-12>Emitted(80, 103) Source(158, 5) + SourceIndex(0)
-13>Emitted(80, 170) Source(161, 47) + SourceIndex(0)
-14>Emitted(80, 172) Source(159, 9) + SourceIndex(0)
-15>Emitted(80, 189) Source(159, 28) + SourceIndex(0)
-16>Emitted(80, 191) Source(159, 9) + SourceIndex(0)
-17>Emitted(80, 233) Source(159, 28) + SourceIndex(0)
-18>Emitted(80, 235) Source(160, 9) + SourceIndex(0)
-19>Emitted(80, 254) Source(160, 32) + SourceIndex(0)
-20>Emitted(80, 256) Source(160, 9) + SourceIndex(0)
-21>Emitted(80, 302) Source(160, 32) + SourceIndex(0)
-22>Emitted(80, 309) Source(162, 22) + SourceIndex(0)
-23>Emitted(80, 310) Source(162, 23) + SourceIndex(0)
-24>Emitted(80, 313) Source(162, 26) + SourceIndex(0)
-25>Emitted(80, 314) Source(162, 27) + SourceIndex(0)
-26>Emitted(80, 316) Source(162, 29) + SourceIndex(0)
-27>Emitted(80, 317) Source(162, 30) + SourceIndex(0)
-28>Emitted(80, 320) Source(162, 33) + SourceIndex(0)
-29>Emitted(80, 321) Source(162, 34) + SourceIndex(0)
-30>Emitted(80, 323) Source(162, 36) + SourceIndex(0)
-31>Emitted(80, 324) Source(162, 37) + SourceIndex(0)
-32>Emitted(80, 326) Source(162, 39) + SourceIndex(0)
-33>Emitted(80, 328) Source(162, 41) + SourceIndex(0)
-34>Emitted(80, 329) Source(162, 42) + SourceIndex(0)
+6 >Emitted(80, 30) Source(157, 5) + SourceIndex(0)
+7 >Emitted(80, 44) Source(157, 20) + SourceIndex(0)
+8 >Emitted(80, 46) Source(157, 5) + SourceIndex(0)
+9 >Emitted(80, 84) Source(157, 20) + SourceIndex(0)
+10>Emitted(80, 86) Source(158, 5) + SourceIndex(0)
+11>Emitted(80, 102) Source(161, 47) + SourceIndex(0)
+12>Emitted(80, 104) Source(158, 5) + SourceIndex(0)
+13>Emitted(80, 171) Source(161, 47) + SourceIndex(0)
+14>Emitted(80, 173) Source(159, 9) + SourceIndex(0)
+15>Emitted(80, 190) Source(159, 28) + SourceIndex(0)
+16>Emitted(80, 192) Source(159, 9) + SourceIndex(0)
+17>Emitted(80, 234) Source(159, 28) + SourceIndex(0)
+18>Emitted(80, 236) Source(160, 9) + SourceIndex(0)
+19>Emitted(80, 255) Source(160, 32) + SourceIndex(0)
+20>Emitted(80, 257) Source(160, 9) + SourceIndex(0)
+21>Emitted(80, 303) Source(160, 32) + SourceIndex(0)
+22>Emitted(80, 316) Source(162, 22) + SourceIndex(0)
+23>Emitted(80, 317) Source(162, 23) + SourceIndex(0)
+24>Emitted(80, 320) Source(162, 26) + SourceIndex(0)
+25>Emitted(80, 321) Source(162, 27) + SourceIndex(0)
+26>Emitted(80, 323) Source(162, 29) + SourceIndex(0)
+27>Emitted(80, 324) Source(162, 30) + SourceIndex(0)
+28>Emitted(80, 327) Source(162, 33) + SourceIndex(0)
+29>Emitted(80, 328) Source(162, 34) + SourceIndex(0)
+30>Emitted(80, 330) Source(162, 36) + SourceIndex(0)
+31>Emitted(80, 331) Source(162, 37) + SourceIndex(0)
+32>Emitted(80, 333) Source(162, 39) + SourceIndex(0)
+33>Emitted(80, 335) Source(162, 41) + SourceIndex(0)
+34>Emitted(80, 336) Source(162, 42) + SourceIndex(0)
 ---
 >>>    console.log(primaryA);
 1 >^^^^
@@ -3272,35 +3296,35 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(82, 1) Source(164, 1) + SourceIndex(0)
 2 >Emitted(82, 2) Source(164, 2) + SourceIndex(0)
 ---
->>>for (_58 = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, _59 = _58.name, name = _59 === void 0 ? "noName" : _59, _60 = _58.skills, _61 = _60 === void 0 ? { primary: "none", secondary: "none" } : _60, _62 = _61.primary, primary = _62 === void 0 ? "primary" : _62, _63 = _61.secondary, secondary = _63 === void 0 ? "secondary" : _63, _58,
+>>>for (_58 = { name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }, (_59 = _58.name, name = _59 === void 0 ? "noName" : _59, _60 = _58.skills, _61 = _60 === void 0 ? { primary: "none", secondary: "none" } : _60, _62 = _61.primary, primary = _62 === void 0 ? "primary" : _62, _63 = _61.secondary, secondary = _63 === void 0 ? "secondary" : _63, _58), _58,
 1->
 2 >^^^
 3 >   ^
 4 >    ^
 5 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-6 >                                                                                    ^^
-7 >                                                                                      ^^^^^^^^^^^^^^
-8 >                                                                                                    ^^
-9 >                                                                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-10>                                                                                                                                            ^^
-11>                                                                                                                                              ^^^^^^^^^^^^^^^^
-12>                                                                                                                                                              ^^
-13>                                                                                                                                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-14>                                                                                                                                                                                                                                   ^^
-15>                                                                                                                                                                                                                                     ^^^^^^^^^^^^^^^^^
-16>                                                                                                                                                                                                                                                      ^^
-17>                                                                                                                                                                                                                                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-18>                                                                                                                                                                                                                                                                                                  ^^
-19>                                                                                                                                                                                                                                                                                                    ^^^^^^^^^^^^^^^^^^^
-20>                                                                                                                                                                                                                                                                                                                       ^^
-21>                                                                                                                                                                                                                                                                                                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+6 >                                                                                    ^^^
+7 >                                                                                       ^^^^^^^^^^^^^^
+8 >                                                                                                     ^^
+9 >                                                                                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+10>                                                                                                                                             ^^
+11>                                                                                                                                               ^^^^^^^^^^^^^^^^
+12>                                                                                                                                                               ^^
+13>                                                                                                                                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+14>                                                                                                                                                                                                                                    ^^
+15>                                                                                                                                                                                                                                      ^^^^^^^^^^^^^^^^^
+16>                                                                                                                                                                                                                                                       ^^
+17>                                                                                                                                                                                                                                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+18>                                                                                                                                                                                                                                                                                                   ^^
+19>                                                                                                                                                                                                                                                                                                     ^^^^^^^^^^^^^^^^^^^
+20>                                                                                                                                                                                                                                                                                                                        ^^
+21>                                                                                                                                                                                                                                                                                                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 1->
   >
 2 >for
@@ -3314,50 +3338,50 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
   >         } = { primary: "none", secondary: "none" }
   >     } = <MultiRobot>{ name: "trimmer", skills: { primary: "trimming", secondary: "edging" } }
 6 >                                                                                    
-7 >                                                                                      name = "noName"
-8 >                                                                                                    
-9 >                                                                                                      name = "noName"
-10>                                                                                                                                            ,
-  >                                                                                                                                                
-11>                                                                                                                                              skills: {
-  >                                                                                                                                                      primary = "primary",
-  >                                                                                                                                                      secondary = "secondary"
-  >                                                                                                                                                  } = { primary: "none", secondary: "none" }
-12>                                                                                                                                                              
-13>                                                                                                                                                                skills: {
-  >                                                                                                                                                                        primary = "primary",
-  >                                                                                                                                                                        secondary = "secondary"
-  >                                                                                                                                                                    } = { primary: "none", secondary: "none" }
-14>                                                                                                                                                                                                                                   
-15>                                                                                                                                                                                                                                     primary = "primary"
-16>                                                                                                                                                                                                                                                      
-17>                                                                                                                                                                                                                                                        primary = "primary"
-18>                                                                                                                                                                                                                                                                                                  ,
-  >                                                                                                                                                                                                                                                                                                          
-19>                                                                                                                                                                                                                                                                                                    secondary = "secondary"
-20>                                                                                                                                                                                                                                                                                                                       
-21>                                                                                                                                                                                                                                                                                                                         secondary = "secondary"
+7 >                                                                                       name = "noName"
+8 >                                                                                                     
+9 >                                                                                                       name = "noName"
+10>                                                                                                                                             ,
+  >                                                                                                                                                 
+11>                                                                                                                                               skills: {
+  >                                                                                                                                                       primary = "primary",
+  >                                                                                                                                                       secondary = "secondary"
+  >                                                                                                                                                   } = { primary: "none", secondary: "none" }
+12>                                                                                                                                                               
+13>                                                                                                                                                                 skills: {
+  >                                                                                                                                                                         primary = "primary",
+  >                                                                                                                                                                         secondary = "secondary"
+  >                                                                                                                                                                     } = { primary: "none", secondary: "none" }
+14>                                                                                                                                                                                                                                    
+15>                                                                                                                                                                                                                                      primary = "primary"
+16>                                                                                                                                                                                                                                                       
+17>                                                                                                                                                                                                                                                         primary = "primary"
+18>                                                                                                                                                                                                                                                                                                   ,
+  >                                                                                                                                                                                                                                                                                                           
+19>                                                                                                                                                                                                                                                                                                     secondary = "secondary"
+20>                                                                                                                                                                                                                                                                                                                        
+21>                                                                                                                                                                                                                                                                                                                          secondary = "secondary"
 1->Emitted(83, 1) Source(165, 1) + SourceIndex(0)
 2 >Emitted(83, 4) Source(165, 4) + SourceIndex(0)
 3 >Emitted(83, 5) Source(165, 5) + SourceIndex(0)
 4 >Emitted(83, 6) Source(165, 6) + SourceIndex(0)
 5 >Emitted(83, 85) Source(171, 90) + SourceIndex(0)
-6 >Emitted(83, 87) Source(166, 5) + SourceIndex(0)
-7 >Emitted(83, 101) Source(166, 20) + SourceIndex(0)
-8 >Emitted(83, 103) Source(166, 5) + SourceIndex(0)
-9 >Emitted(83, 141) Source(166, 20) + SourceIndex(0)
-10>Emitted(83, 143) Source(167, 5) + SourceIndex(0)
-11>Emitted(83, 159) Source(170, 47) + SourceIndex(0)
-12>Emitted(83, 161) Source(167, 5) + SourceIndex(0)
-13>Emitted(83, 228) Source(170, 47) + SourceIndex(0)
-14>Emitted(83, 230) Source(168, 9) + SourceIndex(0)
-15>Emitted(83, 247) Source(168, 28) + SourceIndex(0)
-16>Emitted(83, 249) Source(168, 9) + SourceIndex(0)
-17>Emitted(83, 291) Source(168, 28) + SourceIndex(0)
-18>Emitted(83, 293) Source(169, 9) + SourceIndex(0)
-19>Emitted(83, 312) Source(169, 32) + SourceIndex(0)
-20>Emitted(83, 314) Source(169, 9) + SourceIndex(0)
-21>Emitted(83, 360) Source(169, 32) + SourceIndex(0)
+6 >Emitted(83, 88) Source(166, 5) + SourceIndex(0)
+7 >Emitted(83, 102) Source(166, 20) + SourceIndex(0)
+8 >Emitted(83, 104) Source(166, 5) + SourceIndex(0)
+9 >Emitted(83, 142) Source(166, 20) + SourceIndex(0)
+10>Emitted(83, 144) Source(167, 5) + SourceIndex(0)
+11>Emitted(83, 160) Source(170, 47) + SourceIndex(0)
+12>Emitted(83, 162) Source(167, 5) + SourceIndex(0)
+13>Emitted(83, 229) Source(170, 47) + SourceIndex(0)
+14>Emitted(83, 231) Source(168, 9) + SourceIndex(0)
+15>Emitted(83, 248) Source(168, 28) + SourceIndex(0)
+16>Emitted(83, 250) Source(168, 9) + SourceIndex(0)
+17>Emitted(83, 292) Source(168, 28) + SourceIndex(0)
+18>Emitted(83, 294) Source(169, 9) + SourceIndex(0)
+19>Emitted(83, 313) Source(169, 32) + SourceIndex(0)
+20>Emitted(83, 315) Source(169, 9) + SourceIndex(0)
+21>Emitted(83, 361) Source(169, 32) + SourceIndex(0)
 ---
 >>>    i = 0; i < 1; i++) {
 1 >^^^^
@@ -3434,12 +3458,13 @@ sourceFile:sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2
 >>>}
 1 >
 2 >^
-3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
 1 >
   >
 2 >}
 1 >Emitted(86, 1) Source(174, 1) + SourceIndex(0)
 2 >Emitted(86, 2) Source(174, 2) + SourceIndex(0)
 ---
->>>var _a, _b, _c, _d, _e, _f, _g, _h, _j, _k, _l, _m, _o, _p, _q, _r, _s, _t, _u, _v, _w, _x, _y, _z, _0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, _25, _26, _27, _28, _29, _30, _31, _32, _33, _34, _35, _36, _37, _38, _39, _40, _41, _42, _43, _44, _45, _46, _47, _48, _49, _50, _51, _52, _53, _54, _55, _56, _57, _58, _59, _60, _61, _62, _63;
+>>>var _k, _q, _4, _9, _27, _33, _52, _58;
+>>>var _a, _b, _c, _d, _e, _f, _g, _h, _j, _l, _m, _o, _p, _r, _s, _t, _u, _v, _w, _x, _y, _z, _0, _1, _2, _3, _5, _6, _7, _8, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, _25, _26, _28, _29, _30, _31, _32, _34, _35, _36, _37, _38, _39, _40, _41, _42, _43, _44, _45, _46, _47, _48, _49, _50, _51, _53, _54, _55, _56, _57, _59, _60, _61, _62, _63;
 >>>//# sourceMappingURL=sourceMapValidationDestructuringForObjectBindingPatternDefaultValues2.js.map
\ No newline at end of file

From 334820c357c50f9926ea4c4cbd09f9673755cf65 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 2 Nov 2016 16:26:34 -0700
Subject: [PATCH 156/224] Remove spread types, leaving spread syntax/emit

Spreads are still typed, but cannot be created from a non-object type.
Tests still need to be updated.
---
 src/compiler/checker.ts              | 343 ++++-----------------------
 src/compiler/declarationEmitter.ts   |   9 -
 src/compiler/diagnosticMessages.json |   6 +-
 src/compiler/parser.ts               |  17 --
 src/compiler/types.ts                |  22 +-
 src/lib/es2015.core.d.ts             |   6 +-
 6 files changed, 53 insertions(+), 350 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 5447e652f08fe..c6924e2cb0aa8 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -113,7 +113,6 @@ namespace ts {
         const tupleTypes: GenericType[] = [];
         const unionTypes = createMap<UnionType>();
         const intersectionTypes = createMap<IntersectionType>();
-        const spreadTypes = createMap<SpreadType>();
         const stringLiteralTypes = createMap<LiteralType>();
         const numericLiteralTypes = createMap<LiteralType>();
         const evolvingArrayTypes: EvolvingArrayType[] = [];
@@ -2244,9 +2243,6 @@ namespace ts {
                     else if (type.flags & TypeFlags.UnionOrIntersection) {
                         writeUnionOrIntersectionType(<UnionOrIntersectionType>type, nextFlags);
                     }
-                    else if (type.flags & TypeFlags.Spread) {
-                        writeSpreadType(<SpreadType>type);
-                    }
                     else if (getObjectFlags(type) & ObjectFlags.Anonymous) {
                         writeAnonymousType(<ObjectType>type, nextFlags);
                     }
@@ -2362,48 +2358,6 @@ namespace ts {
                     }
                 }
 
-                function writeSpreadType(type: SpreadType) {
-                    writePunctuation(writer, SyntaxKind.OpenBraceToken);
-                    writer.writeLine();
-                    writer.increaseIndent();
-
-                    writeSpreadTypeWorker(type, /*atEnd*/true, type.symbol);
-
-                    writer.decreaseIndent();
-                    writePunctuation(writer, SyntaxKind.CloseBraceToken);
-                }
-
-                function writeSpreadTypeWorker(type: SpreadType, atEnd: boolean, container: Symbol): void {
-                    if (type.left.flags & TypeFlags.Spread) {
-                        writeSpreadTypeWorker(type.left as SpreadType, /*atEnd*/false, container);
-                    }
-                    else {
-                        const saveInObjectTypeLiteral = inObjectTypeLiteral;
-                        inObjectTypeLiteral = true;
-                        writeObjectLiteralType(resolveStructuredTypeMembers(type.left as ResolvedType));
-                        inObjectTypeLiteral = saveInObjectTypeLiteral;
-                    }
-                    if (type.right.symbol === container) {
-                        // if type.right was written as part of the spread type, don't surround with ...{ }.
-                        // this gives { a: number, ... T } instead of { ...{ a: number }, ...T }
-                        const saveInObjectTypeLiteral = inObjectTypeLiteral;
-                        inObjectTypeLiteral = true;
-                        writeObjectLiteralType(resolveStructuredTypeMembers(type.right as ResolvedType));
-                        inObjectTypeLiteral = saveInObjectTypeLiteral;
-                    }
-                    else {
-                        writePunctuation(writer, SyntaxKind.DotDotDotToken);
-                        writeType(type.right, TypeFormatFlags.None);
-                        if (atEnd) {
-                            writeSpace(writer);
-                        }
-                        else {
-                            writePunctuation(writer, SyntaxKind.SemicolonToken);
-                            writer.writeLine();
-                        }
-                    }
-                }
-
                 function writeAnonymousType(type: ObjectType, flags: TypeFormatFlags) {
                     const symbol = type.symbol;
                     if (symbol) {
@@ -3623,7 +3577,6 @@ namespace ts {
                 links.type = getUnionType([getTypeOfSymbol(links.leftSpread), getTypeOfSymbol(links.rightSpread)]);
             }
             return links.type;
-
         }
 
         function getTargetType(type: Type): Type {
@@ -4567,10 +4520,6 @@ namespace ts {
             return type.resolvedApparentType;
         }
 
-        function getApparentTypeOfSpread(type: SpreadType) {
-            return getApparentType(type.right);
-        }
-
         /**
          * For a type parameter, return the base constraint of the type parameter. For the string, number,
          * boolean, and symbol primitive types, return the corresponding object types. Otherwise return the
@@ -4578,7 +4527,6 @@ namespace ts {
          */
         function getApparentType(type: Type): Type {
             let t = type.flags & TypeFlags.TypeParameter ? getApparentTypeOfTypeParameter(<TypeParameter>type) : type;
-            t = t.flags & TypeFlags.Spread ? getApparentTypeOfSpread(type as SpreadType) : t;
             return t.flags & TypeFlags.StringLike ? globalStringType :
                 t.flags & TypeFlags.NumberLike ? globalNumberType :
                 t.flags & TypeFlags.BooleanLike ? globalBooleanType :
@@ -4640,7 +4588,7 @@ namespace ts {
                 propTypes.push(type);
             }
             const result = <TransientSymbol>createSymbol(SymbolFlags.Property | SymbolFlags.Transient | SymbolFlags.SyntheticProperty | commonFlags, name);
-            result.syntheticKind === SyntheticSymbolKind.UnionOrIntersection;
+            result.syntheticKind = SyntheticSymbolKind.UnionOrIntersection;
             result.containingType = containingType;
             result.hasNonUniformType = hasNonUniformType;
             result.isPartial = isPartial;
@@ -5917,12 +5865,6 @@ namespace ts {
         function getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node: Node, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
             const links = getNodeLinks(node);
             if (!links.resolvedType) {
-                const hasSpread = (node.kind === SyntaxKind.TypeLiteral &&
-                                   find((node as TypeLiteralNode).members, elt => elt.kind === SyntaxKind.SpreadTypeElement));
-                if (hasSpread) {
-                    return getTypeFromSpreadTypeLiteral(node, aliasSymbol, aliasTypeArguments);
-                }
-
                 // Deferred resolution of members is handled by resolveObjectTypeMembers
                 if (isEmpty(node.symbol.members) && !aliasSymbol && !aliasTypeArguments) {
                     links.resolvedType = emptyTypeLiteralType;
@@ -5937,187 +5879,56 @@ namespace ts {
             return links.resolvedType;
         }
 
-        function getTypeFromSpreadTypeLiteral(node: Node, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
-            let spread: Type = emptyObjectType;
-            let members: Map<Symbol>;
-            let stringIndexInfo: IndexInfo;
-            let numberIndexInfo: IndexInfo;
-            for (const member of (node as TypeLiteralNode).members) {
-                if (member.kind === SyntaxKind.SpreadTypeElement) {
-                    if (members) {
-                        const type = createAnonymousType(node.symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
-                        spread = getSpreadType(spread, type, node.symbol, aliasSymbol, aliasTypeArguments);
-                        members = undefined;
-                        stringIndexInfo = undefined;
-                        numberIndexInfo = undefined;
-                    }
-                    const type = getTypeFromTypeNode((member as SpreadTypeElement).type);
-                    spread = getSpreadType(spread, type, node.symbol, aliasSymbol, aliasTypeArguments);
-                }
-                else if (member.kind !== SyntaxKind.IndexSignature &&
-                         member.kind !== SyntaxKind.CallSignature &&
-                         member.kind !== SyntaxKind.ConstructSignature) {
-                    // it is an error for spread types to include index, call or construct signatures
-                    const flags = SymbolFlags.Property | SymbolFlags.Transient | (member.questionToken ? SymbolFlags.Optional : 0);
-                    const text = getTextOfPropertyName(member.name);
-                    const symbol = <TransientSymbol>createSymbol(flags, text);
-                    symbol.declarations = [member];
-                    symbol.valueDeclaration = member;
-                    symbol.type = getTypeFromTypeNodeNoAlias((member as IndexSignatureDeclaration | PropertySignature | MethodSignature).type);
-                    if (!members) {
-                        members = createMap<Symbol>();
-                    }
-                    members[symbol.name] = symbol;
-                }
-            }
-            if (members || stringIndexInfo || numberIndexInfo) {
-                const type = createAnonymousType(node.symbol, members || emptySymbols, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
-                spread = getSpreadType(spread, type, node.symbol, aliasSymbol, aliasTypeArguments);
-            }
-            return spread;
-        }
-
         /**
          * Since the source of spread types are object literals and type literals, which are not binary,
          * this function should be called in a left folding style, with left = previous result of getSpreadType
          * and right = the new element to be spread.
          */
-        function getSpreadType(left: Type, right: Type, symbol: Symbol, aliasSymbol?: Symbol, aliasTypeArguments?: Type[]): Type {
-            const id = getTypeListId([left, right]);
-            if (id in spreadTypes) {
-                return spreadTypes[id];
-            }
+        function getSpreadType(left: Type, right: Type, symbol: Symbol): ResolvedType {
+            Debug.assert(!!(left.flags & TypeFlags.Object) && !!(right.flags & TypeFlags.Object), "Only object types may be spread.");
+            const members = createMap<Symbol>();
+            const skippedPrivateMembers = createMap<boolean>();
+            const stringIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.String), getIndexInfoOfType(right, IndexKind.String));
+            const numberIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.Number), getIndexInfoOfType(right, IndexKind.Number));
 
-            // any spreads to any
-            if (left.flags & TypeFlags.Any || right.flags & TypeFlags.Any) {
-                return anyType;
-            }
-            // flatten intersections to objects if all member types are objects
-            if (left.flags & TypeFlags.Intersection) {
-                left = resolveObjectIntersection(left as IntersectionType);
-            }
-            if (right.flags & TypeFlags.Intersection) {
-                right = resolveObjectIntersection(right as IntersectionType);
-            }
-            // distribute unions
-            if (left.flags & TypeFlags.Union) {
-                const spreads = map((left as UnionType).types,
-                                    t => getSpreadType(t, right, symbol, aliasSymbol, aliasTypeArguments));
-                return getUnionType(spreads, /*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
-            }
-            if (right.flags & TypeFlags.Union) {
-                const spreads = map((right as UnionType).types,
-                                    t => getSpreadType(left, t, symbol, aliasSymbol, aliasTypeArguments));
-                return getUnionType(spreads, /*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
-            }
-            // skip primitives
-            if (left.flags & TypeFlags.Primitive && right.flags & TypeFlags.Primitive) {
-                return emptyObjectType;
+            const isFromSpread = right.symbol !== symbol;
+            for (const rightProp of getPropertiesOfType(right)) {
+                if (getDeclarationModifierFlagsFromSymbol(rightProp) & (ModifierFlags.Private | ModifierFlags.Protected)) {
+                    skippedPrivateMembers[rightProp.name] = true;
+                }
+                else if (!(rightProp.flags & SymbolFlags.Method && isFromSpread) &&
+                         !(rightProp.flags & SymbolFlags.SetAccessor && !(rightProp.flags & SymbolFlags.GetAccessor))) {
+                    // skip methods from spreads and accessors with setters but no getters
+                    members[rightProp.name] = rightProp;
+                }
             }
-            else if (left.flags & TypeFlags.Primitive) {
-                return right;
-            }
-            else if (right.flags & TypeFlags.Primitive) {
-                return left;
-            }
-
-            // spread simplifications
-            if (left.flags & TypeFlags.Spread &&
-                right.flags & TypeFlags.TypeParameter &&
-                (left as SpreadType).right.flags & TypeFlags.TypeParameter &&
-                right.symbol === (left as SpreadType).right.symbol) {
-                // for types like T ... T, just return ... T
-                return left;
-            }
-            if (left.flags & TypeFlags.Spread &&
-                right.flags & TypeFlags.Object &&
-                (left as SpreadType).right.flags & TypeFlags.Object) {
-                // simplify two adjacent object types: T ... { x } ... { y } becomes T ... { x, y }
-                const simplified = getSpreadType(right, (left as SpreadType).right, symbol, aliasSymbol, aliasTypeArguments);
-                return getSpreadType((left as SpreadType).left, simplified, symbol, aliasSymbol, aliasTypeArguments);
-            }
-            if (right.flags & TypeFlags.Spread) {
-                // spread is right associative and associativity applies, so transform
-                // (T ... U) ... V to T ... (U ... V)
-                const rspread = right as SpreadType;
-                if (rspread.left === emptyObjectType) {
-                    // ... U ... ({} ... T) => ... U ... T
-                    return getSpreadType(left, rspread.right, symbol, aliasSymbol, aliasTypeArguments);
-                }
-                return getSpreadType(getSpreadType(left, rspread.left, symbol, aliasSymbol, aliasTypeArguments),
-                                     rspread.right, symbol, aliasSymbol, aliasTypeArguments);
-            }
-
-            // create an object type if left and right are both objects,
-            // otherwise create a spread type
-            if (right.flags & TypeFlags.Object && left.flags & TypeFlags.Object) {
-                const members = createMap<Symbol>();
-                const skippedPrivateMembers = createMap<boolean>();
-                const stringIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.String), getIndexInfoOfType(right, IndexKind.String));
-                const numberIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.Number), getIndexInfoOfType(right, IndexKind.Number));
-
-                const isFromSpread = right.symbol !== symbol;
-                for (const rightProp of getPropertiesOfType(right)) {
-                    if (getDeclarationModifierFlagsFromSymbol(rightProp) & (ModifierFlags.Private | ModifierFlags.Protected)) {
-                        skippedPrivateMembers[rightProp.name] = true;
-                    }
-                    else if (!(rightProp.flags & SymbolFlags.Method && isFromSpread) &&
-                             !(rightProp.flags & SymbolFlags.SetAccessor && !(rightProp.flags & SymbolFlags.GetAccessor))) {
-                        // skip methods from spreads and accessors with setters but no getters
-                        members[rightProp.name] = rightProp;
-                    }
-                }
-                for (const leftProp of getPropertiesOfType(left)) {
-                    if (leftProp.flags & SymbolFlags.SetAccessor && !(leftProp.flags & SymbolFlags.GetAccessor)
-                       || leftProp.name in skippedPrivateMembers) {
-                        continue;
-                    }
-                    if (leftProp.name in members) {
-                        const rightProp = members[leftProp.name];
-                        if (rightProp.flags & SymbolFlags.Optional) {
-                            const declarations: Declaration[] = concatenate(leftProp.declarations, rightProp.declarations);
-                            const flags = SymbolFlags.Property | SymbolFlags.Transient | SymbolFlags.SyntheticProperty | (leftProp.flags & SymbolFlags.Optional);
-                            const result = <TransientSymbol>createSymbol(flags, leftProp.name);
-                            result.syntheticKind = SyntheticSymbolKind.Spread;
-                            result.leftSpread = leftProp;
-                            result.rightSpread = rightProp;
-                            result.declarations = declarations;
-                            if (declarations.length) {
-                                result.valueDeclaration = declarations[0];
-                            }
-                            result.isReadonly = isReadonlySymbol(leftProp) || isReadonlySymbol(rightProp);
-                            members[leftProp.name] = result;
+            for (const leftProp of getPropertiesOfType(left)) {
+                if (leftProp.flags & SymbolFlags.SetAccessor && !(leftProp.flags & SymbolFlags.GetAccessor)
+                    || leftProp.name in skippedPrivateMembers) {
+                    continue;
+                }
+                if (leftProp.name in members) {
+                    const rightProp = members[leftProp.name];
+                    if (rightProp.flags & SymbolFlags.Optional) {
+                        const declarations: Declaration[] = concatenate(leftProp.declarations, rightProp.declarations);
+                        const flags = SymbolFlags.Property | SymbolFlags.Transient | SymbolFlags.SyntheticProperty | (leftProp.flags & SymbolFlags.Optional);
+                        const result = <TransientSymbol>createSymbol(flags, leftProp.name);
+                        result.syntheticKind = SyntheticSymbolKind.Spread;
+                        result.leftSpread = leftProp;
+                        result.rightSpread = rightProp;
+                        result.declarations = declarations;
+                        if (declarations.length) {
+                            result.valueDeclaration = declarations[0];
                         }
-                    }
-                    else {
-                        members[leftProp.name] = leftProp;
+                        result.isReadonly = isReadonlySymbol(leftProp) || isReadonlySymbol(rightProp);
+                        members[leftProp.name] = result;
                     }
                 }
-                return createAnonymousType(symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
-            }
-            const spread = spreadTypes[id] = createType(TypeFlags.Spread) as SpreadType;
-            Debug.assert(!!(left.flags & (TypeFlags.Spread | TypeFlags.Object)), "Left flags: " + left.flags.toString(2));
-            Debug.assert(!!(right.flags & (TypeFlags.TypeParameter | TypeFlags.Intersection | TypeFlags.Index | TypeFlags.IndexedAccess | TypeFlags.Object)), "Right flags: " + right.flags.toString(2));
-            spread.symbol = symbol;
-            spread.left = left as SpreadType | ResolvedType;
-            spread.right = right as TypeParameter | IntersectionType | IndexType | IndexedAccessType | ResolvedType;
-            spread.aliasSymbol = aliasSymbol;
-            spread.aliasTypeArguments = aliasTypeArguments;
-            return spread;
-        }
-
-        function resolveObjectIntersection(intersection: IntersectionType): IntersectionType | ResolvedType {
-            if (find(intersection.types, t => !(t.flags & TypeFlags.Object))) {
-                return intersection;
-            }
-            const properties = getPropertiesOfType(intersection);
-            const members = createMap<Symbol>();
-            for (const property of properties) {
-                members[property.name] = property;
+                else {
+                    members[leftProp.name] = leftProp;
+                }
             }
-            const stringIndex = getIndexInfoOfType(intersection, IndexKind.String);
-            const numberIndex = getIndexInfoOfType(intersection, IndexKind.Number);
-            return createAnonymousType(undefined, members, emptyArray, emptyArray, stringIndex, numberIndex);
+            return createAnonymousType(symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
         }
 
         function createLiteralType(flags: TypeFlags, text: string) {
@@ -6535,10 +6346,6 @@ namespace ts {
                 if (type.flags & TypeFlags.Intersection) {
                     return getIntersectionType(instantiateList((<IntersectionType>type).types, mapper, instantiateType), type.aliasSymbol, mapper.targetTypes);
                 }
-                if (type.flags & TypeFlags.Spread) {
-                    const spread = type as SpreadType;
-                    return getSpreadType(instantiateType(spread.left, mapper), instantiateType(spread.right, mapper), type.symbol, type.aliasSymbol, mapper.targetTypes);
-                }
                 if (type.flags & TypeFlags.Index) {
                     return getIndexType(instantiateType((<IndexType>type).type, mapper));
                 }
@@ -7089,30 +6896,7 @@ namespace ts {
                     }
                 }
 
-                if (source.flags & TypeFlags.Spread && target.flags & TypeFlags.Spread) {
-                    // you only see this for spreads with type parameters
-                    if (!(spreadTypeRelatedTo(source as SpreadType, target as SpreadType, /*atRightEdge*/ true))) {
-                        if (reportErrors) {
-                            reportRelationError(headMessage, source, target);
-                        }
-                        return Ternary.False;
-                    }
-                    const reportStructuralErrors = reportErrors && errorInfo === saveErrorInfo;
-                    const apparentSource = getApparentType(source);
-                    if (result = objectTypeRelatedTo(apparentSource, source, getApparentType(target), reportStructuralErrors)) {
-                        errorInfo = saveErrorInfo;
-                        return result;
-                    }
-                }
-
                 if (source.flags & TypeFlags.TypeParameter) {
-                    if (target.flags & TypeFlags.Spread) {
-                        // T is assignable to ...T
-                        if (source.symbol === (target as SpreadType).right.symbol
-                            && (target as SpreadType).left === emptyObjectType) {
-                            return Ternary.True;
-                        }
-                    }
                     let constraint = getConstraintOfTypeParameter(<TypeParameter>source);
 
                     if (!constraint || constraint.flags & TypeFlags.Any) {
@@ -7164,32 +6948,6 @@ namespace ts {
                 return Ternary.False;
             }
 
-            function spreadTypeRelatedTo(source: SpreadType, target: SpreadType, atRightEdge?: boolean): boolean {
-                // If the right side of a spread type is ObjectType, then the left side must be a Spread.
-                // Structural compatibility of the spreads' object types are checked separately in isRelatedTo,
-                // so just skip them for now.
-                if (source.right.flags & TypeFlags.Object || target.right.flags & TypeFlags.Object) {
-                    return atRightEdge &&
-                        spreadTypeRelatedTo(source.right.flags & TypeFlags.Object ? source.left as SpreadType : source,
-                                            target.right.flags & TypeFlags.Object ? target.left as SpreadType : target);
-                }
-                // If both right sides are type parameters, intersections, index types or indexed access types,
-                // then they must be identical for the spread types to be related.
-                // It also means that the left sides are either spread types or object types.
-
-                // if one left is object and the other is spread, that means the second has another type parameter. which isn't allowed
-                if (target.right !== source.right) {
-                    return false;
-                }
-                if (source.left.flags & TypeFlags.Spread && target.left.flags & TypeFlags.Spread) {
-                    // If the left sides are both spread types, then recursively check them.
-                    return spreadTypeRelatedTo(source.left as SpreadType, target.left as SpreadType);
-                }
-                // If the left sides are both object types, then we should be at the end and both should be emptyObjectType.
-                // If not, we can't know what properties might have been overwritten, so fail.
-                return source.left === emptyObjectType && target.left === emptyObjectType;
-            }
-
             function isIdenticalTo(source: Type, target: Type): Ternary {
                 let result: Ternary;
                 if (source.flags & TypeFlags.Object && target.flags & TypeFlags.Object) {
@@ -11167,6 +10925,10 @@ namespace ts {
                         typeFlags = 0;
                     }
                     const type = checkExpression((memberDecl as SpreadElementExpression).expression);
+                    if (!(type.flags & TypeFlags.Object)) {
+                        error(memberDecl, Diagnostics.Spread_types_may_only_be_created_from_object_types);
+                        return unknownType;
+                    }
                     spread = getSpreadType(spread, type, node.symbol);
                     continue;
                 }
@@ -15403,13 +15165,6 @@ namespace ts {
                     checkTypeForDuplicateIndexSignatures(node);
                     checkObjectTypeForDuplicateDeclarations(node);
                 }
-                if (find(node.members, p => p.kind === SyntaxKind.SpreadTypeElement)) {
-                    for (const signature of filter(node.members, p => p.kind === SyntaxKind.IndexSignature ||
-                                                                      p.kind === SyntaxKind.CallSignature ||
-                                                                      p.kind === SyntaxKind.ConstructSignature)) {
-                        error(signature, Diagnostics.Type_literals_with_spreads_cannot_contain_index_call_or_construct_signatures);
-                    }
-                }
             }
         }
 
@@ -17467,9 +17222,7 @@ namespace ts {
                 // perform property check if property or indexer is declared in 'type'
                 // this allows to rule out cases when both property and indexer are inherited from the base class
                 let errorNode: Node;
-                    if (prop.valueDeclaration.name.kind === SyntaxKind.ComputedPropertyName ||
-                        prop.parent === containingType.symbol ||
-                        containingType.flags & TypeFlags.Spread) {
+                    if (prop.valueDeclaration.name.kind === SyntaxKind.ComputedPropertyName || prop.parent === containingType.symbol) {
                     errorNode = prop.valueDeclaration;
                 }
                 else if (indexDeclaration) {
@@ -20699,12 +20452,6 @@ namespace ts {
                     checkGrammarHeritageClause(heritageClause);
                 }
             }
-
-            let result: TypeElement;
-            if (result = find(node.members, e => e.kind === SyntaxKind.SpreadTypeElement)) {
-                return grammarErrorOnNode(result, Diagnostics.Interface_declaration_cannot_contain_a_spread_property);
-            }
-
             return false;
         }
 
diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index 7a23ba8722bdd..0bba375a2cb2e 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -1138,13 +1138,6 @@ namespace ts {
             writeLine();
         }
 
-        function emitSpreadTypeElement(type: SpreadTypeElement) {
-            write("...");
-            emitType(type.type);
-            write(";");
-            writeLine();
-        }
-
         function emitVariableDeclaration(node: VariableDeclaration | PropertyDeclaration | PropertySignature | ParameterDeclaration) {
             // If we are emitting property it isn't moduleElement and hence we already know it needs to be emitted
             // so there is no check needed to see if declaration is visible
@@ -1729,8 +1722,6 @@ namespace ts {
                 case SyntaxKind.PropertyDeclaration:
                 case SyntaxKind.PropertySignature:
                     return emitPropertyDeclaration(<PropertyDeclaration>node);
-                case SyntaxKind.SpreadTypeElement:
-                    return emitSpreadTypeElement(node as SpreadTypeElement);
                 case SyntaxKind.EnumMember:
                     return emitEnumMemberDeclaration(<EnumMember>node);
                 case SyntaxKind.ExportAssignment:
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 1d45e96cb6f6b..58c59b18f5e45 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1983,14 +1983,10 @@
         "category": "Error",
         "code": 2697
     },
-    "Interface declaration cannot contain a spread property.": {
+    "Spread types may only be created from object types.": {
         "category": "Error",
         "code": 2698
     },
-    "Type literals with spreads cannot contain index, call or construct signatures.": {
-        "category": "Error",
-        "code": 2699
-    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index ac41d78bb1232..464f6ca01d802 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -76,8 +76,6 @@ namespace ts {
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).objectAssignmentInitializer);
             case SyntaxKind.SpreadElementExpression:
                 return visitNode(cbNode, (<SpreadElementExpression>node).expression);
-            case SyntaxKind.SpreadTypeElement:
-                return visitNode(cbNode, (node as SpreadTypeElement).type);
             case SyntaxKind.Parameter:
             case SyntaxKind.PropertyDeclaration:
             case SyntaxKind.PropertySignature:
@@ -2346,10 +2344,6 @@ namespace ts {
             if (token() === SyntaxKind.OpenBracketToken) {
                 return true;
             }
-            // spread elements are type members
-            if (token() === SyntaxKind.DotDotDotToken) {
-                return true;
-            }
             // Try to get the first property-like token following all modifiers
             if (isLiteralPropertyName()) {
                 idToken = token();
@@ -2375,9 +2369,6 @@ namespace ts {
             if (token() === SyntaxKind.NewKeyword && lookAhead(isStartOfConstructSignature)) {
                 return parseSignatureMember(SyntaxKind.ConstructSignature);
             }
-            if (token() === SyntaxKind.DotDotDotToken) {
-                return parseSpreadTypeElement();
-            }
             const fullStart = getNodePos();
             const modifiers = parseModifiers();
             if (isIndexSignature()) {
@@ -2386,14 +2377,6 @@ namespace ts {
             return parsePropertyOrMethodSignature(fullStart, modifiers);
         }
 
-        function parseSpreadTypeElement() {
-            const element = createNode(SyntaxKind.SpreadTypeElement, scanner.getStartPos()) as SpreadTypeElement;
-            parseTokenNode<Node>(); // parse `...`
-            element.type = parseType();
-            parseTypeMemberSemicolon();
-            return finishNode(element);
-        }
-
         function isStartOfConstructSignature() {
             nextToken();
             return token() === SyntaxKind.OpenParenToken || token() === SyntaxKind.LessThanToken;
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index ba5e6b2db9971..d3b4cb3b6e7df 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -321,8 +321,6 @@ namespace ts {
         PropertyAssignment,
         ShorthandPropertyAssignment,
         SpreadElementExpression,
-        SpreadTypeElement,
-
 
         // Enum
         EnumMember,
@@ -664,11 +662,6 @@ namespace ts {
         initializer?: Expression;           // Optional initializer
     }
 
-    // @kind(SyntaxKind.SpreadTypeElement)
-    export interface SpreadTypeElement extends TypeElement {
-        type: TypeNode;
-    }
-
     // @kind(SyntaxKind.PropertyDeclaration)
     export interface PropertyDeclaration extends ClassElement {
         kind: SyntaxKind.PropertyDeclaration;
@@ -2521,7 +2514,7 @@ namespace ts {
         Merged                  = 0x02000000,  // Merged symbol (created during program binding)
         Transient               = 0x04000000,  // Transient symbol (created during type check)
         Prototype               = 0x08000000,  // Prototype property (no source representation)
-        SyntheticProperty       = 0x10000000,  // Property in union, intersection or spread type
+        SyntheticProperty       = 0x10000000,  // Property in union or intersection type
         Optional                = 0x20000000,  // Optional property
         ExportStar              = 0x40000000,  // Export * declaration
 
@@ -2711,7 +2704,6 @@ namespace ts {
         ContainsObjectLiteral   = 1 << 22,  // Type is or contains object literal type
         /* @internal */
         ContainsAnyFunctionType = 1 << 23,  // Type is or contains object literal type
-        Spread                  = 1 << 24,  // Spread types
 
         /* @internal */
         Nullable = Undefined | Null,
@@ -2729,12 +2721,12 @@ namespace ts {
         BooleanLike = Boolean | BooleanLiteral,
         EnumLike = Enum | EnumLiteral,
         UnionOrIntersection = Union | Intersection,
-        StructuredType = Object | Union | Intersection | Spread,
+        StructuredType = Object | Union | Intersection,
         StructuredOrTypeParameter = StructuredType | TypeParameter,
 
         // 'Narrowable' types are types where narrowing actually narrows.
         // This *should* be every type other than null, undefined, void, and never
-        Narrowable = Any | StructuredType | TypeParameter | Index | IndexedAccess | StringLike | NumberLike | BooleanLike | ESSymbol | Spread,
+        Narrowable = Any | StructuredType | TypeParameter | Index | IndexedAccess | StringLike | NumberLike | BooleanLike | ESSymbol,
         NotUnionOrUnit = Any | ESSymbol | Object,
         /* @internal */
         RequiresWidening = ContainsWideningType | ContainsObjectLiteral,
@@ -2849,12 +2841,6 @@ namespace ts {
 
     export type StructuredType = ObjectType | UnionType | IntersectionType;
 
-    /* @internal */
-    export interface SpreadType extends Type {
-        left: SpreadType | ResolvedType;
-        right: TypeParameter | IntersectionType | IndexType | IndexedAccessType | ResolvedType;
-    }
-
     /* @internal */
     // An instantiated anonymous type has a target and a mapper
     export interface AnonymousType extends ObjectType {
@@ -2868,7 +2854,7 @@ namespace ts {
     }
 
     /* @internal */
-    // Resolved object, spread, union, or intersection type
+    // Resolved object, union, or intersection type
     export interface ResolvedType extends ObjectType, UnionOrIntersectionType {
         members: SymbolTable;              // Properties by name
         properties: Symbol[];              // Properties
diff --git a/src/lib/es2015.core.d.ts b/src/lib/es2015.core.d.ts
index cc61445effed1..28f2e12248bbe 100644
--- a/src/lib/es2015.core.d.ts
+++ b/src/lib/es2015.core.d.ts
@@ -278,7 +278,7 @@ interface ObjectConstructor {
       * @param target The target object to copy to.
       * @param source The source object from which to copy properties.
       */
-    assign<T, U>(target: T, source: U): { ...T, ...U };
+    assign<T, U>(target: T, source: U): T & U;
 
     /**
       * Copy the values of all of the enumerable own properties from one or more source objects to a
@@ -287,7 +287,7 @@ interface ObjectConstructor {
       * @param source1 The first source object from which to copy properties.
       * @param source2 The second source object from which to copy properties.
       */
-    assign<T, U, V>(target: T, source1: U, source2: V): { ...T, ...U, ...V };
+    assign<T, U, V>(target: T, source1: U, source2: V): T & U & V;
 
     /**
       * Copy the values of all of the enumerable own properties from one or more source objects to a
@@ -297,7 +297,7 @@ interface ObjectConstructor {
       * @param source2 The second source object from which to copy properties.
       * @param source3 The third source object from which to copy properties.
       */
-    assign<T, U, V, W>(target: T, source1: U, source2: V, source3: W): { ...T, ...U, ...V, ...W };
+    assign<T, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W;
 
     /**
       * Copy the values of all of the enumerable own properties from one or more source objects to a

From a6320203bec279d0d8db6ce9d479aba29ef0d388 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 2 Nov 2016 16:31:04 -0700
Subject: [PATCH 157/224] Fix lint

---
 src/compiler/checker.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index c6924e2cb0aa8..872aad6b046b7 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4526,7 +4526,7 @@ namespace ts {
          * type itself. Note that the apparent type of a union type is the union type itself.
          */
         function getApparentType(type: Type): Type {
-            let t = type.flags & TypeFlags.TypeParameter ? getApparentTypeOfTypeParameter(<TypeParameter>type) : type;
+            const t = type.flags & TypeFlags.TypeParameter ? getApparentTypeOfTypeParameter(<TypeParameter>type) : type;
             return t.flags & TypeFlags.StringLike ? globalStringType :
                 t.flags & TypeFlags.NumberLike ? globalNumberType :
                 t.flags & TypeFlags.BooleanLike ? globalBooleanType :

From e8c3d62d99023b8d1c2eb188bce29f5c7f00402e Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 3 Nov 2016 08:14:40 -0700
Subject: [PATCH 158/224] Lock tslint version to 4.0.0-dev.0, because
 4.0.0-dev.1 complains about unnecessary semicolons following properties

---
 package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package.json b/package.json
index 1f943f89788d6..3bf9dbcff7b54 100644
--- a/package.json
+++ b/package.json
@@ -76,7 +76,7 @@
         "travis-fold": "latest",
         "ts-node": "latest",
         "tsd": "latest",
-        "tslint": "next",
+        "tslint": "4.0.0-dev.0",
         "typescript": "next"
     },
     "scripts": {

From a077fd104aa6be0237bc6dfe00f57528c6fb89e1 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 3 Nov 2016 09:39:58 -0700
Subject: [PATCH 159/224] Remove spread type tests from spread tests

---
 tests/baselines/reference/objectSpread.js     |  47 +---
 .../baselines/reference/objectSpread.symbols  | 225 +++++-------------
 tests/baselines/reference/objectSpread.types  | 140 +----------
 .../reference/objectSpreadGeneric.errors.txt  | 148 ------------
 .../reference/objectSpreadGeneric.js          | 141 -----------
 .../objectSpreadIndexSignature.errors.txt     |  35 ---
 .../reference/objectSpreadIndexSignature.js   |  56 ++---
 .../objectSpreadIndexSignature.symbols        |  42 ++++
 .../objectSpreadIndexSignature.types          |  52 ++++
 .../reference/objectSpreadNegative.errors.txt | 135 +++++------
 .../reference/objectSpreadNegative.js         |  86 +++----
 .../objectSpreadNegativeParse.errors.txt      |  14 +-
 .../types/spread/interfaceSpread.ts           |   8 -
 .../conformance/types/spread/objectSpread.ts  |  23 +-
 .../types/spread/objectSpreadGeneric.ts       |  72 ------
 .../spread/objectSpreadIndexSignature.ts      |  25 +-
 .../types/spread/objectSpreadInference.ts     |  19 --
 .../types/spread/objectSpreadIntersection.ts  |  36 ---
 .../types/spread/objectSpreadNegative.ts      |  47 ++--
 .../types/spread/objectSpreadScenarios.ts     |  17 --
 .../types/spread/objectSpreadUnion.ts         |  23 --
 .../fourslash/findAllRefsForObjectSpread.ts   |   4 +-
 .../fourslash/goToDefinitionObjectSpread.ts   |   4 +-
 tests/cases/fourslash/renameObjectSpread.ts   |   4 +-
 24 files changed, 348 insertions(+), 1055 deletions(-)
 delete mode 100644 tests/baselines/reference/objectSpreadGeneric.errors.txt
 delete mode 100644 tests/baselines/reference/objectSpreadGeneric.js
 delete mode 100644 tests/baselines/reference/objectSpreadIndexSignature.errors.txt
 create mode 100644 tests/baselines/reference/objectSpreadIndexSignature.symbols
 create mode 100644 tests/baselines/reference/objectSpreadIndexSignature.types
 delete mode 100644 tests/cases/conformance/types/spread/interfaceSpread.ts
 delete mode 100644 tests/cases/conformance/types/spread/objectSpreadGeneric.ts
 delete mode 100644 tests/cases/conformance/types/spread/objectSpreadInference.ts
 delete mode 100644 tests/cases/conformance/types/spread/objectSpreadIntersection.ts
 delete mode 100644 tests/cases/conformance/types/spread/objectSpreadScenarios.ts
 delete mode 100644 tests/cases/conformance/types/spread/objectSpreadUnion.ts

diff --git a/tests/baselines/reference/objectSpread.js b/tests/baselines/reference/objectSpread.js
index 23729d4cd6f21..c19ead478cbd8 100644
--- a/tests/baselines/reference/objectSpread.js
+++ b/tests/baselines/reference/objectSpread.js
@@ -35,13 +35,8 @@ let getter: { a: number, c: number } =
     { ...op, c: 7 }
 getter.a = 12;
 
-// null, undefined, functions and primitives result in { }
-let spreadNull = { ...null };
-let spreadUndefind = { ...undefined };
-let spreadNum = { ...12 };
-let spreadBool = { ...false };
+// functions result in { }
 let spreadFunc = { ...(function () { }) };
-let spreadStr = { ...'foo' };
 
 // methods are not enumerable
 class C { p = 1; m() { } }
@@ -80,22 +75,6 @@ let computedAfter: { a: number, b: string, "at the end": number } =
 let a = 12;
 let shortCutted: { a: number, b: string } = { ...o, a }
 
-// generics
-function f<T, U>(t: T, u: U): { ...T, ...U, id: string } {
-    return { ...t, ...u, id: 'id' };
-}
-let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
-    f({ a: 1, b: 'yes' }, { c: 'no', d: false })
-let overlap: { id: string, a: number, b: string } =
-    f({ a: 1 }, { a: 2, b: 'extra' })
-let overlapConflict: { id:string, a: string } =
-    f({ a: 1 }, { a: 'mismatch' })
-let overwriteId: { id: string, a: number, c: number, d: string } =
-    f({ a: 1, id: true }, { c: 1, d: 'no' })
-
-class D { m() { }; q = 2; }
-let classesAreWrong: { id: string, ...C, ...D } =
-    f(new C(), new D())
 
 
 //// [objectSpread.js]
@@ -128,13 +107,8 @@ var propertyNested = __assign({ a: __assign({}, o) });
 var op = { get a() { return 6; } };
 var getter = __assign({}, op, { c: 7 });
 getter.a = 12;
-// null, undefined, functions and primitives result in { }
-var spreadNull = __assign({}, null);
-var spreadUndefind = __assign({}, undefined);
-var spreadNum = __assign({}, 12);
-var spreadBool = __assign({}, false);
+// functions result in { }
 var spreadFunc = __assign({}, (function () { }));
-var spreadStr = __assign({}, 'foo');
 // methods are not enumerable
 var C = (function () {
     function C() {
@@ -167,21 +141,4 @@ var computedAfter = __assign({}, o, (_c = { b: 'yeah' }, _c['at the end'] = 14,
 // shortcut syntax
 var a = 12;
 var shortCutted = __assign({}, o, { a: a });
-// generics
-function f(t, u) {
-    return __assign({}, t, u, { id: 'id' });
-}
-var exclusive = f({ a: 1, b: 'yes' }, { c: 'no', d: false });
-var overlap = f({ a: 1 }, { a: 2, b: 'extra' });
-var overlapConflict = f({ a: 1 }, { a: 'mismatch' });
-var overwriteId = f({ a: 1, id: true }, { c: 1, d: 'no' });
-var D = (function () {
-    function D() {
-        this.q = 2;
-    }
-    D.prototype.m = function () { };
-    ;
-    return D;
-}());
-var classesAreWrong = f(new C(), new D());
 var _a, _b, _c;
diff --git a/tests/baselines/reference/objectSpread.symbols b/tests/baselines/reference/objectSpread.symbols
index 039be9e0d7df5..b95f8273724c2 100644
--- a/tests/baselines/reference/objectSpread.symbols
+++ b/tests/baselines/reference/objectSpread.symbols
@@ -150,224 +150,127 @@ getter.a = 12;
 >getter : Symbol(getter, Decl(objectSpread.ts, 32, 3))
 >a : Symbol(a, Decl(objectSpread.ts, 32, 13))
 
-// null, undefined, functions and primitives result in { }
-let spreadNull = { ...null };
->spreadNull : Symbol(spreadNull, Decl(objectSpread.ts, 37, 3))
-
-let spreadUndefind = { ...undefined };
->spreadUndefind : Symbol(spreadUndefind, Decl(objectSpread.ts, 38, 3))
-
-let spreadNum = { ...12 };
->spreadNum : Symbol(spreadNum, Decl(objectSpread.ts, 39, 3))
-
-let spreadBool = { ...false };
->spreadBool : Symbol(spreadBool, Decl(objectSpread.ts, 40, 3))
-
+// functions result in { }
 let spreadFunc = { ...(function () { }) };
->spreadFunc : Symbol(spreadFunc, Decl(objectSpread.ts, 41, 3))
-
-let spreadStr = { ...'foo' };
->spreadStr : Symbol(spreadStr, Decl(objectSpread.ts, 42, 3))
+>spreadFunc : Symbol(spreadFunc, Decl(objectSpread.ts, 37, 3))
 
 // methods are not enumerable
 class C { p = 1; m() { } }
->C : Symbol(C, Decl(objectSpread.ts, 42, 29))
->p : Symbol(C.p, Decl(objectSpread.ts, 45, 9))
->m : Symbol(C.m, Decl(objectSpread.ts, 45, 16))
+>C : Symbol(C, Decl(objectSpread.ts, 37, 42))
+>p : Symbol(C.p, Decl(objectSpread.ts, 40, 9))
+>m : Symbol(C.m, Decl(objectSpread.ts, 40, 16))
 
 let c: C = new C()
->c : Symbol(c, Decl(objectSpread.ts, 46, 3))
->C : Symbol(C, Decl(objectSpread.ts, 42, 29))
->C : Symbol(C, Decl(objectSpread.ts, 42, 29))
+>c : Symbol(c, Decl(objectSpread.ts, 41, 3))
+>C : Symbol(C, Decl(objectSpread.ts, 37, 42))
+>C : Symbol(C, Decl(objectSpread.ts, 37, 42))
 
 let spreadC: { p: number } = { ...c }
->spreadC : Symbol(spreadC, Decl(objectSpread.ts, 47, 3))
->p : Symbol(p, Decl(objectSpread.ts, 47, 14))
+>spreadC : Symbol(spreadC, Decl(objectSpread.ts, 42, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 42, 14))
 
 // own methods are enumerable
 let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } };
->cplus : Symbol(cplus, Decl(objectSpread.ts, 50, 3))
->p : Symbol(p, Decl(objectSpread.ts, 50, 12))
->plus : Symbol(plus, Decl(objectSpread.ts, 50, 23))
->plus : Symbol(plus, Decl(objectSpread.ts, 50, 48))
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 45, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 45, 12))
+>plus : Symbol(plus, Decl(objectSpread.ts, 45, 23))
+>plus : Symbol(plus, Decl(objectSpread.ts, 45, 48))
 
 cplus.plus();
->cplus.plus : Symbol(plus, Decl(objectSpread.ts, 50, 23))
->cplus : Symbol(cplus, Decl(objectSpread.ts, 50, 3))
->plus : Symbol(plus, Decl(objectSpread.ts, 50, 23))
+>cplus.plus : Symbol(plus, Decl(objectSpread.ts, 45, 23))
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 45, 3))
+>plus : Symbol(plus, Decl(objectSpread.ts, 45, 23))
 
 // new field's type conflicting with existing field is OK
 let changeTypeAfter: { a: string, b: string } =
->changeTypeAfter : Symbol(changeTypeAfter, Decl(objectSpread.ts, 54, 3))
->a : Symbol(a, Decl(objectSpread.ts, 54, 22))
->b : Symbol(b, Decl(objectSpread.ts, 54, 33))
+>changeTypeAfter : Symbol(changeTypeAfter, Decl(objectSpread.ts, 49, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 49, 22))
+>b : Symbol(b, Decl(objectSpread.ts, 49, 33))
 
     { ...o, a: 'wrong type?' }
->a : Symbol(a, Decl(objectSpread.ts, 55, 11))
+>a : Symbol(a, Decl(objectSpread.ts, 50, 11))
 
 let changeTypeBefore: { a: number, b: string } =
->changeTypeBefore : Symbol(changeTypeBefore, Decl(objectSpread.ts, 56, 3))
->a : Symbol(a, Decl(objectSpread.ts, 56, 23))
->b : Symbol(b, Decl(objectSpread.ts, 56, 34))
+>changeTypeBefore : Symbol(changeTypeBefore, Decl(objectSpread.ts, 51, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 51, 23))
+>b : Symbol(b, Decl(objectSpread.ts, 51, 34))
 
     { a: 'wrong type?', ...o };
->a : Symbol(a, Decl(objectSpread.ts, 57, 5))
+>a : Symbol(a, Decl(objectSpread.ts, 52, 5))
 
 let changeTypeBoth: { a: string, b: number } =
->changeTypeBoth : Symbol(changeTypeBoth, Decl(objectSpread.ts, 58, 3))
->a : Symbol(a, Decl(objectSpread.ts, 58, 21))
->b : Symbol(b, Decl(objectSpread.ts, 58, 32))
+>changeTypeBoth : Symbol(changeTypeBoth, Decl(objectSpread.ts, 53, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 53, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 53, 32))
 
     { ...o, ...swap };
 
 // optional
 let definiteBoolean: { sn: boolean };
->definiteBoolean : Symbol(definiteBoolean, Decl(objectSpread.ts, 62, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 62, 22))
+>definiteBoolean : Symbol(definiteBoolean, Decl(objectSpread.ts, 57, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 57, 22))
 
 let definiteString: { sn: string };
->definiteString : Symbol(definiteString, Decl(objectSpread.ts, 63, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 63, 21))
+>definiteString : Symbol(definiteString, Decl(objectSpread.ts, 58, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 58, 21))
 
 let optionalString: { sn?: string };
->optionalString : Symbol(optionalString, Decl(objectSpread.ts, 64, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 64, 21))
+>optionalString : Symbol(optionalString, Decl(objectSpread.ts, 59, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 59, 21))
 
 let optionalNumber: { sn?: number };
->optionalNumber : Symbol(optionalNumber, Decl(objectSpread.ts, 65, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 65, 21))
+>optionalNumber : Symbol(optionalNumber, Decl(objectSpread.ts, 60, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 60, 21))
 
 let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
->optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpread.ts, 66, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 66, 25))
+>optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpread.ts, 61, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 61, 25))
 
 let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
->optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpread.ts, 67, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 67, 30))
+>optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpread.ts, 62, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 62, 30))
 
 let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
->allOptional : Symbol(allOptional, Decl(objectSpread.ts, 68, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 68, 18))
+>allOptional : Symbol(allOptional, Decl(objectSpread.ts, 63, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 63, 18))
 
 // computed property
 let computedFirst: { a: number, b: string, "before everything": number } =
->computedFirst : Symbol(computedFirst, Decl(objectSpread.ts, 71, 3))
->a : Symbol(a, Decl(objectSpread.ts, 71, 20))
->b : Symbol(b, Decl(objectSpread.ts, 71, 31))
+>computedFirst : Symbol(computedFirst, Decl(objectSpread.ts, 66, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 66, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 66, 31))
 
     { ['before everything']: 12, ...o, b: 'yes' }
->'before everything' : Symbol(['before everything'], Decl(objectSpread.ts, 72, 5))
->b : Symbol(b, Decl(objectSpread.ts, 72, 38))
+>'before everything' : Symbol(['before everything'], Decl(objectSpread.ts, 67, 5))
+>b : Symbol(b, Decl(objectSpread.ts, 67, 38))
 
 let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
->computedMiddle : Symbol(computedMiddle, Decl(objectSpread.ts, 73, 3))
->a : Symbol(a, Decl(objectSpread.ts, 73, 21))
->b : Symbol(b, Decl(objectSpread.ts, 73, 32))
->c : Symbol(c, Decl(objectSpread.ts, 73, 43))
+>computedMiddle : Symbol(computedMiddle, Decl(objectSpread.ts, 68, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 68, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 68, 32))
+>c : Symbol(c, Decl(objectSpread.ts, 68, 43))
 
     { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
->'in the middle' : Symbol(['in the middle'], Decl(objectSpread.ts, 74, 11))
->b : Symbol(b, Decl(objectSpread.ts, 74, 34))
+>'in the middle' : Symbol(['in the middle'], Decl(objectSpread.ts, 69, 11))
+>b : Symbol(b, Decl(objectSpread.ts, 69, 34))
 
 let computedAfter: { a: number, b: string, "at the end": number } =
->computedAfter : Symbol(computedAfter, Decl(objectSpread.ts, 75, 3))
->a : Symbol(a, Decl(objectSpread.ts, 75, 20))
->b : Symbol(b, Decl(objectSpread.ts, 75, 31))
+>computedAfter : Symbol(computedAfter, Decl(objectSpread.ts, 70, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 70, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 70, 31))
 
     { ...o, b: 'yeah', ['at the end']: 14 }
->b : Symbol(b, Decl(objectSpread.ts, 76, 11))
->'at the end' : Symbol(['at the end'], Decl(objectSpread.ts, 76, 22))
+>b : Symbol(b, Decl(objectSpread.ts, 71, 11))
+>'at the end' : Symbol(['at the end'], Decl(objectSpread.ts, 71, 22))
 
 // shortcut syntax
 let a = 12;
->a : Symbol(a, Decl(objectSpread.ts, 78, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 73, 3))
 
 let shortCutted: { a: number, b: string } = { ...o, a }
->shortCutted : Symbol(shortCutted, Decl(objectSpread.ts, 79, 3))
->a : Symbol(a, Decl(objectSpread.ts, 79, 18))
->b : Symbol(b, Decl(objectSpread.ts, 79, 29))
->a : Symbol(a, Decl(objectSpread.ts, 79, 51))
-
-// generics
-function f<T, U>(t: T, u: U): { ...T, ...U, id: string } {
->f : Symbol(f, Decl(objectSpread.ts, 79, 55))
->T : Symbol(T, Decl(objectSpread.ts, 82, 11))
->U : Symbol(U, Decl(objectSpread.ts, 82, 13))
->t : Symbol(t, Decl(objectSpread.ts, 82, 17))
->T : Symbol(T, Decl(objectSpread.ts, 82, 11))
->u : Symbol(u, Decl(objectSpread.ts, 82, 22))
->U : Symbol(U, Decl(objectSpread.ts, 82, 13))
->T : Symbol(T, Decl(objectSpread.ts, 82, 11))
->U : Symbol(U, Decl(objectSpread.ts, 82, 13))
->id : Symbol(id, Decl(objectSpread.ts, 82, 43))
-
-    return { ...t, ...u, id: 'id' };
->id : Symbol(id, Decl(objectSpread.ts, 83, 24))
-}
-let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
->exclusive : Symbol(exclusive, Decl(objectSpread.ts, 85, 3))
->id : Symbol(id, Decl(objectSpread.ts, 85, 16))
->a : Symbol(a, Decl(objectSpread.ts, 85, 28))
->b : Symbol(b, Decl(objectSpread.ts, 85, 39))
->c : Symbol(c, Decl(objectSpread.ts, 85, 50))
->d : Symbol(d, Decl(objectSpread.ts, 85, 61))
-
-    f({ a: 1, b: 'yes' }, { c: 'no', d: false })
->f : Symbol(f, Decl(objectSpread.ts, 79, 55))
->a : Symbol(a, Decl(objectSpread.ts, 86, 7))
->b : Symbol(b, Decl(objectSpread.ts, 86, 13))
->c : Symbol(c, Decl(objectSpread.ts, 86, 27))
->d : Symbol(d, Decl(objectSpread.ts, 86, 36))
-
-let overlap: { id: string, a: number, b: string } =
->overlap : Symbol(overlap, Decl(objectSpread.ts, 87, 3))
->id : Symbol(id, Decl(objectSpread.ts, 87, 14))
->a : Symbol(a, Decl(objectSpread.ts, 87, 26))
->b : Symbol(b, Decl(objectSpread.ts, 87, 37))
-
-    f({ a: 1 }, { a: 2, b: 'extra' })
->f : Symbol(f, Decl(objectSpread.ts, 79, 55))
->a : Symbol(a, Decl(objectSpread.ts, 88, 7))
->a : Symbol(a, Decl(objectSpread.ts, 88, 17))
->b : Symbol(b, Decl(objectSpread.ts, 88, 23))
-
-let overlapConflict: { id:string, a: string } =
->overlapConflict : Symbol(overlapConflict, Decl(objectSpread.ts, 89, 3))
->id : Symbol(id, Decl(objectSpread.ts, 89, 22))
->a : Symbol(a, Decl(objectSpread.ts, 89, 33))
-
-    f({ a: 1 }, { a: 'mismatch' })
->f : Symbol(f, Decl(objectSpread.ts, 79, 55))
->a : Symbol(a, Decl(objectSpread.ts, 90, 7))
->a : Symbol(a, Decl(objectSpread.ts, 90, 17))
-
-let overwriteId: { id: string, a: number, c: number, d: string } =
->overwriteId : Symbol(overwriteId, Decl(objectSpread.ts, 91, 3))
->id : Symbol(id, Decl(objectSpread.ts, 91, 18))
->a : Symbol(a, Decl(objectSpread.ts, 91, 30))
->c : Symbol(c, Decl(objectSpread.ts, 91, 41))
->d : Symbol(d, Decl(objectSpread.ts, 91, 52))
-
-    f({ a: 1, id: true }, { c: 1, d: 'no' })
->f : Symbol(f, Decl(objectSpread.ts, 79, 55))
->a : Symbol(a, Decl(objectSpread.ts, 92, 7))
->id : Symbol(id, Decl(objectSpread.ts, 92, 13))
->c : Symbol(c, Decl(objectSpread.ts, 92, 27))
->d : Symbol(d, Decl(objectSpread.ts, 92, 33))
-
-class D { m() { }; q = 2; }
->D : Symbol(D, Decl(objectSpread.ts, 92, 44))
->m : Symbol(D.m, Decl(objectSpread.ts, 94, 9))
->q : Symbol(D.q, Decl(objectSpread.ts, 94, 18))
-
-let classesAreWrong: { id: string, ...C, ...D } =
->classesAreWrong : Symbol(classesAreWrong, Decl(objectSpread.ts, 95, 3))
->id : Symbol(id, Decl(objectSpread.ts, 95, 22))
->C : Symbol(C, Decl(objectSpread.ts, 42, 29))
->D : Symbol(D, Decl(objectSpread.ts, 92, 44))
-
-    f(new C(), new D())
->f : Symbol(f, Decl(objectSpread.ts, 79, 55))
->C : Symbol(C, Decl(objectSpread.ts, 42, 29))
->D : Symbol(D, Decl(objectSpread.ts, 92, 44))
+>shortCutted : Symbol(shortCutted, Decl(objectSpread.ts, 74, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 74, 18))
+>b : Symbol(b, Decl(objectSpread.ts, 74, 29))
+>a : Symbol(a, Decl(objectSpread.ts, 74, 51))
+
 
diff --git a/tests/baselines/reference/objectSpread.types b/tests/baselines/reference/objectSpread.types
index 78f4f7583d939..e9b9a6421c297 100644
--- a/tests/baselines/reference/objectSpread.types
+++ b/tests/baselines/reference/objectSpread.types
@@ -223,36 +223,13 @@ getter.a = 12;
 >a : number
 >12 : 12
 
-// null, undefined, functions and primitives result in { }
-let spreadNull = { ...null };
->spreadNull : {}
->{ ...null } : {}
->null : null
-
-let spreadUndefind = { ...undefined };
->spreadUndefind : {}
->{ ...undefined } : {}
->undefined : any
-
-let spreadNum = { ...12 };
->spreadNum : {}
->{ ...12 } : {}
-
-let spreadBool = { ...false };
->spreadBool : {}
->{ ...false } : {}
->false : false
-
+// functions result in { }
 let spreadFunc = { ...(function () { }) };
 >spreadFunc : {}
 >{ ...(function () { }) } : {}
 >(function () { }) : () => void
 >function () { } : () => void
 
-let spreadStr = { ...'foo' };
->spreadStr : {}
->{ ...'foo' } : {}
-
 // methods are not enumerable
 class C { p = 1; m() { } }
 >C : C
@@ -421,119 +398,4 @@ let shortCutted: { a: number, b: string } = { ...o, a }
 >o : any
 >a : number
 
-// generics
-function f<T, U>(t: T, u: U): { ...T, ...U, id: string } {
->f : <T, U>(t: T, u: U) => { ...T; ...U; id: string; }
->T : T
->U : U
->t : T
->T : T
->u : U
->U : U
->T : T
->U : U
->id : string
-
-    return { ...t, ...u, id: 'id' };
->{ ...t, ...u, id: 'id' } : { ...T; ...U; id: string; }
->t : any
->u : any
->id : string
->'id' : "id"
-}
-let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
->exclusive : { id: string; a: number; b: string; c: string; d: boolean; }
->id : string
->a : number
->b : string
->c : string
->d : boolean
-
-    f({ a: 1, b: 'yes' }, { c: 'no', d: false })
->f({ a: 1, b: 'yes' }, { c: 'no', d: false }) : { id: string; c: string; d: boolean; a: number; b: string; }
->f : <T, U>(t: T, u: U) => { ...T; ...U; id: string; }
->{ a: 1, b: 'yes' } : { a: number; b: string; }
->a : number
->1 : 1
->b : string
->'yes' : "yes"
->{ c: 'no', d: false } : { c: string; d: false; }
->c : string
->'no' : "no"
->d : boolean
->false : false
-
-let overlap: { id: string, a: number, b: string } =
->overlap : { id: string; a: number; b: string; }
->id : string
->a : number
->b : string
-
-    f({ a: 1 }, { a: 2, b: 'extra' })
->f({ a: 1 }, { a: 2, b: 'extra' }) : { id: string; a: number; b: string; }
->f : <T, U>(t: T, u: U) => { ...T; ...U; id: string; }
->{ a: 1 } : { a: number; }
->a : number
->1 : 1
->{ a: 2, b: 'extra' } : { a: number; b: string; }
->a : number
->2 : 2
->b : string
->'extra' : "extra"
-
-let overlapConflict: { id:string, a: string } =
->overlapConflict : { id: string; a: string; }
->id : string
->a : string
-
-    f({ a: 1 }, { a: 'mismatch' })
->f({ a: 1 }, { a: 'mismatch' }) : { id: string; a: string; }
->f : <T, U>(t: T, u: U) => { ...T; ...U; id: string; }
->{ a: 1 } : { a: number; }
->a : number
->1 : 1
->{ a: 'mismatch' } : { a: string; }
->a : string
->'mismatch' : "mismatch"
-
-let overwriteId: { id: string, a: number, c: number, d: string } =
->overwriteId : { id: string; a: number; c: number; d: string; }
->id : string
->a : number
->c : number
->d : string
-
-    f({ a: 1, id: true }, { c: 1, d: 'no' })
->f({ a: 1, id: true }, { c: 1, d: 'no' }) : { id: string; c: number; d: string; a: number; }
->f : <T, U>(t: T, u: U) => { ...T; ...U; id: string; }
->{ a: 1, id: true } : { a: number; id: true; }
->a : number
->1 : 1
->id : boolean
->true : true
->{ c: 1, d: 'no' } : { c: number; d: string; }
->c : number
->1 : 1
->d : string
->'no' : "no"
-
-class D { m() { }; q = 2; }
->D : D
->m : () => void
->q : number
->2 : 2
-
-let classesAreWrong: { id: string, ...C, ...D } =
->classesAreWrong : { q: number; p: number; id: string; }
->id : string
->C : C
->D : D
-
-    f(new C(), new D())
->f(new C(), new D()) : { id: string; q: number; p: number; }
->f : <T, U>(t: T, u: U) => { ...T; ...U; id: string; }
->new C() : C
->C : typeof C
->new D() : D
->D : typeof D
 
diff --git a/tests/baselines/reference/objectSpreadGeneric.errors.txt b/tests/baselines/reference/objectSpreadGeneric.errors.txt
deleted file mode 100644
index f1e2b7e4828f5..0000000000000
--- a/tests/baselines/reference/objectSpreadGeneric.errors.txt
+++ /dev/null
@@ -1,148 +0,0 @@
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(9,5): error TS2322: Type '{ ...U }' is not assignable to type 'U'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(10,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...V; ...U; ...T }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(11,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...T; ...V }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(12,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...V }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(13,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...V }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(14,11): error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...U }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(16,11): error TS2322: Type '{ first: string; ...T; ...U }' is not assignable to type '{ first: string; ...T; ...U }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(19,11): error TS2322: Type '{}' is not assignable to type '{ ...T; ...U }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(26,11): error TS2322: Type '{ sn?: boolean; ...T; sn?: string | number; }' is not assignable to type '{ ...T; sn?: string | number | boolean; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(32,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(34,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; second: string; ...T; third: string; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(36,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; secondsecond: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; secondsecond: string; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(38,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; secondsecond: string; }' is not assignable to type '{ first: string; second: string; secondsecond: string; third: string; ...T; ...U }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(42,11): error TS2322: Type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(44,11): error TS2322: Type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(46,11): error TS2322: Type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(57,5): error TS2322: Type '{ ...keyof U }' is not assignable to type '{ ...keyof T }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(58,5): error TS2322: Type '{ ...keyof T }' is not assignable to type '{ ...keyof U }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(61,5): error TS2322: Type '{ ...K }' is not assignable to type '{ ...keyof T }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(62,5): error TS2322: Type '{ ...keyof T }' is not assignable to type '{ ...K }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(63,5): error TS2322: Type '{ ...J }' is not assignable to type '{ ...keyof U }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(64,5): error TS2322: Type '{ ...keyof U }' is not assignable to type '{ ...J }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(70,5): error TS2322: Type '{ ...U[J] }' is not assignable to type '{ ...T[K] }'.
-tests/cases/conformance/types/spread/objectSpreadGeneric.ts(71,5): error TS2322: Type '{ ...T[K] }' is not assignable to type '{ ...U[J] }'.
-
-
-==== tests/cases/conformance/types/spread/objectSpreadGeneric.ts (24 errors) ====
-    function f<T, U, V>(t: T, u: U, v: V): void {
-        let o: { ...T, ...U, ...V };
-        let uus: { ...U, ...U};
-        let us: { ...U };
-        const same: { ...T, ...U, ...V } = o; // ok
-        uus = us; // ok, multiple spreads are equivalent to a single one
-        us = uus; // ok, multiple spreads are equivalent to a single one
-        us = u;   // ok, type has at least all the properties of the spread
-        u = us;   // error, might be missing a ton of stuff
-        ~
-!!! error TS2322: Type '{ ...U }' is not assignable to type 'U'.
-        const reversed: { ...V, ...U, ...T } = o; // error, reversed
-              ~~~~~~~~
-!!! error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...V; ...U; ...T }'.
-        const reversed2: { ...U, ...T, ...V } = o; // error, U and T are still reversed
-              ~~~~~~~~~
-!!! error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...T; ...V }'.
-        const missingT: { ...U, ...V } = o; // error, missing T
-              ~~~~~~~~
-!!! error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...U; ...V }'.
-        const missingU: { ...T, ...V } = o; // error, missing U
-              ~~~~~~~~
-!!! error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...V }'.
-        const missingV: { ...T, ...U } = o; // error, missing V
-              ~~~~~~~~
-!!! error TS2322: Type '{ ...T; ...U; ...V }' is not assignable to type '{ ...T; ...U }'.
-        const atEnd: { ...T, ...U, second: string } = { ...t, ...u, second: 'foo' }; // ok
-        const atBeginning: { first: string, ...T, ...U, } = { first: 'foo', ...t, ...u }; // error, not assignable
-              ~~~~~~~~~~~
-!!! error TS2322: Type '{ first: string; ...T; ...U }' is not assignable to type '{ first: string; ...T; ...U }'.
-    
-        const emptyTarget: { } = { ...t, ...u } // ok
-        const emptySource: { ...T, ...U } = { }; // error, {} is not assignable to U (or T)
-              ~~~~~~~~~~~
-!!! error TS2322: Type '{}' is not assignable to type '{ ...T; ...U }'.
-    
-        // error, { sn?: boolean } ...T ... { sn?: number | string } is not assignable to
-        //        T ... { sn?: number | string | boolean }
-        let optionalNumber: { sn?: number };
-        let optionalString: { sn?: string };
-        let optionalBoolean: { sn?: boolean };
-        const unionCutoff: { ...T, sn?: number | string | boolean } =
-              ~~~~~~~~~~~
-!!! error TS2322: Type '{ sn?: boolean; ...T; sn?: string | number; }' is not assignable to type '{ ...T; sn?: string | number | boolean; }'.
-            { ...optionalBoolean, ...t, ...optionalString, ...optionalNumber }
-        unionCutoff.sn; // ok
-        const optionalCutoff = { ...t, ...optionalNumber }; // ok
-        optionalCutoff.sn; // ok
-    
-        const interspersed: { first: string, ...T, second: string, ...U, third: string } =
-              ~~~~~~~~~~~~
-!!! error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-            { first: '1', ...t, second: '2', ...u, third: '3' }; // error, not assignable
-        const interspersedMissingU: { first: string, second: string, ...T, third: string } =
-              ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; second: string; ...T; third: string; }'.
-            { first: '1', ...t, second: '2', ...u, third: '3' }; // error, 'U' is missing
-        const interspersedOrder1: { first: string, ...T, second: string, ...U, third: string, secondsecond: string } =
-              ~~~~~~~~~~~~~~~~~~
-!!! error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; secondsecond: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; secondsecond: string; }'.
-            { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // error, not assignable
-        const interspersedOrder2: { first: string, second: string, secondsecond: string, third: string, ...T, ...U } =
-              ~~~~~~~~~~~~~~~~~~
-!!! error TS2322: Type '{ first: string; ...T; second: string; ...U; third: string; secondsecond: string; }' is not assignable to type '{ first: string; second: string; secondsecond: string; third: string; ...T; ...U }'.
-            { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // error, not assignable
-    
-    
-        const mismatchFirst: { first: string, ...T, second: string, ...U, third: string } =
-              ~~~~~~~~~~~~~
-!!! error TS2322: Type '{ firrrrrrst: string; ...T; second: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-            { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, not assignable
-        const mismatchSecond: { first: string, ...T, second: string, ...U, third: string } =
-              ~~~~~~~~~~~~~~
-!!! error TS2322: Type '{ first: string; ...T; ssssssssecond: string; ...U; third: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-            { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, not assignable
-        const mismatchLast: { first: string, ...T, second: string, ...U, third: string } =
-              ~~~~~~~~~~~~
-!!! error TS2322: Type '{ first: string; ...T; second: string; ...U; thirrrrrrrd: string; }' is not assignable to type '{ first: string; ...T; second: string; ...U; third: string; }'.
-            { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, not assignable
-    }
-    
-    function indexAccessedTest<T, K extends keyof T, U, J extends keyof U>(t: T, u: U, key1: K, key2: J) {
-        let k1: { ...keyof T };
-        let k2: { ...keyof U };
-        let k3: { ...K };
-        let k4: { ...J };
-        k1 = k1; // ok
-        k2 = k2; // ok
-        k1 = k2; // error
-        ~~
-!!! error TS2322: Type '{ ...keyof U }' is not assignable to type '{ ...keyof T }'.
-        k2 = k1; // error
-        ~~
-!!! error TS2322: Type '{ ...keyof T }' is not assignable to type '{ ...keyof U }'.
-        k3 = k3; // ok
-        k4 = k4; // ok
-        k1 = k3; // error
-        ~~
-!!! error TS2322: Type '{ ...K }' is not assignable to type '{ ...keyof T }'.
-        k3 = k1; // error
-        ~~
-!!! error TS2322: Type '{ ...keyof T }' is not assignable to type '{ ...K }'.
-        k2 = k4; // error
-        ~~
-!!! error TS2322: Type '{ ...J }' is not assignable to type '{ ...keyof U }'.
-        k4 = k2; // error
-        ~~
-!!! error TS2322: Type '{ ...keyof U }' is not assignable to type '{ ...J }'.
-    
-        let i1: { ...T[K] };
-        let i2: { ...U[J] };
-        i1 = i1; // ok
-        i2 = i2; // ok
-        i1 = i2; // error
-        ~~
-!!! error TS2322: Type '{ ...U[J] }' is not assignable to type '{ ...T[K] }'.
-        i2 = i1; // error
-        ~~
-!!! error TS2322: Type '{ ...T[K] }' is not assignable to type '{ ...U[J] }'.
-    }
-    
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadGeneric.js b/tests/baselines/reference/objectSpreadGeneric.js
deleted file mode 100644
index 8e89ebeef6416..0000000000000
--- a/tests/baselines/reference/objectSpreadGeneric.js
+++ /dev/null
@@ -1,141 +0,0 @@
-//// [objectSpreadGeneric.ts]
-function f<T, U, V>(t: T, u: U, v: V): void {
-    let o: { ...T, ...U, ...V };
-    let uus: { ...U, ...U};
-    let us: { ...U };
-    const same: { ...T, ...U, ...V } = o; // ok
-    uus = us; // ok, multiple spreads are equivalent to a single one
-    us = uus; // ok, multiple spreads are equivalent to a single one
-    us = u;   // ok, type has at least all the properties of the spread
-    u = us;   // error, might be missing a ton of stuff
-    const reversed: { ...V, ...U, ...T } = o; // error, reversed
-    const reversed2: { ...U, ...T, ...V } = o; // error, U and T are still reversed
-    const missingT: { ...U, ...V } = o; // error, missing T
-    const missingU: { ...T, ...V } = o; // error, missing U
-    const missingV: { ...T, ...U } = o; // error, missing V
-    const atEnd: { ...T, ...U, second: string } = { ...t, ...u, second: 'foo' }; // ok
-    const atBeginning: { first: string, ...T, ...U, } = { first: 'foo', ...t, ...u }; // error, not assignable
-
-    const emptyTarget: { } = { ...t, ...u } // ok
-    const emptySource: { ...T, ...U } = { }; // error, {} is not assignable to U (or T)
-
-    // error, { sn?: boolean } ...T ... { sn?: number | string } is not assignable to
-    //        T ... { sn?: number | string | boolean }
-    let optionalNumber: { sn?: number };
-    let optionalString: { sn?: string };
-    let optionalBoolean: { sn?: boolean };
-    const unionCutoff: { ...T, sn?: number | string | boolean } =
-        { ...optionalBoolean, ...t, ...optionalString, ...optionalNumber }
-    unionCutoff.sn; // ok
-    const optionalCutoff = { ...t, ...optionalNumber }; // ok
-    optionalCutoff.sn; // ok
-
-    const interspersed: { first: string, ...T, second: string, ...U, third: string } =
-        { first: '1', ...t, second: '2', ...u, third: '3' }; // error, not assignable
-    const interspersedMissingU: { first: string, second: string, ...T, third: string } =
-        { first: '1', ...t, second: '2', ...u, third: '3' }; // error, 'U' is missing
-    const interspersedOrder1: { first: string, ...T, second: string, ...U, third: string, secondsecond: string } =
-        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // error, not assignable
-    const interspersedOrder2: { first: string, second: string, secondsecond: string, third: string, ...T, ...U } =
-        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // error, not assignable
-
-
-    const mismatchFirst: { first: string, ...T, second: string, ...U, third: string } =
-        { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, not assignable
-    const mismatchSecond: { first: string, ...T, second: string, ...U, third: string } =
-        { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, not assignable
-    const mismatchLast: { first: string, ...T, second: string, ...U, third: string } =
-        { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, not assignable
-}
-
-function indexAccessedTest<T, K extends keyof T, U, J extends keyof U>(t: T, u: U, key1: K, key2: J) {
-    let k1: { ...keyof T };
-    let k2: { ...keyof U };
-    let k3: { ...K };
-    let k4: { ...J };
-    k1 = k1; // ok
-    k2 = k2; // ok
-    k1 = k2; // error
-    k2 = k1; // error
-    k3 = k3; // ok
-    k4 = k4; // ok
-    k1 = k3; // error
-    k3 = k1; // error
-    k2 = k4; // error
-    k4 = k2; // error
-
-    let i1: { ...T[K] };
-    let i2: { ...U[J] };
-    i1 = i1; // ok
-    i2 = i2; // ok
-    i1 = i2; // error
-    i2 = i1; // error
-}
-
-
-//// [objectSpreadGeneric.js]
-var __assign = (this && this.__assign) || Object.assign || function(t) {
-    for (var s, i = 1, n = arguments.length; i < n; i++) {
-        s = arguments[i];
-        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
-            t[p] = s[p];
-    }
-    return t;
-};
-function f(t, u, v) {
-    var o;
-    var uus;
-    var us;
-    var same = o; // ok
-    uus = us; // ok, multiple spreads are equivalent to a single one
-    us = uus; // ok, multiple spreads are equivalent to a single one
-    us = u; // ok, type has at least all the properties of the spread
-    u = us; // error, might be missing a ton of stuff
-    var reversed = o; // error, reversed
-    var reversed2 = o; // error, U and T are still reversed
-    var missingT = o; // error, missing T
-    var missingU = o; // error, missing U
-    var missingV = o; // error, missing V
-    var atEnd = __assign({}, t, u, { second: 'foo' }); // ok
-    var atBeginning = __assign({ first: 'foo' }, t, u); // error, not assignable
-    var emptyTarget = __assign({}, t, u); // ok
-    var emptySource = {}; // error, {} is not assignable to U (or T)
-    // error, { sn?: boolean } ...T ... { sn?: number | string } is not assignable to
-    //        T ... { sn?: number | string | boolean }
-    var optionalNumber;
-    var optionalString;
-    var optionalBoolean;
-    var unionCutoff = __assign({}, optionalBoolean, t, optionalString, optionalNumber);
-    unionCutoff.sn; // ok
-    var optionalCutoff = __assign({}, t, optionalNumber); // ok
-    optionalCutoff.sn; // ok
-    var interspersed = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3' }); // error, not assignable
-    var interspersedMissingU = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3' }); // error, 'U' is missing
-    var interspersedOrder1 = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3', secondsecond: 'false' }); // error, not assignable
-    var interspersedOrder2 = __assign({ first: '1' }, t, { second: '2' }, u, { third: '3', secondsecond: 'false' }); // error, not assignable
-    var mismatchFirst = __assign({ firrrrrrst: '1' }, t, { second: '2' }, u, { third: '3' }); // error, not assignable
-    var mismatchSecond = __assign({ first: '1' }, t, { ssssssssecond: '2' }, u, { third: '3' }); // error, not assignable
-    var mismatchLast = __assign({ first: '1' }, t, { second: '2' }, u, { thirrrrrrrd: '3' }); // error, not assignable
-}
-function indexAccessedTest(t, u, key1, key2) {
-    var k1;
-    var k2;
-    var k3;
-    var k4;
-    k1 = k1; // ok
-    k2 = k2; // ok
-    k1 = k2; // error
-    k2 = k1; // error
-    k3 = k3; // ok
-    k4 = k4; // ok
-    k1 = k3; // error
-    k3 = k1; // error
-    k2 = k4; // error
-    k4 = k2; // error
-    var i1;
-    var i2;
-    i1 = i1; // ok
-    i2 = i2; // ok
-    i1 = i2; // error
-    i2 = i1; // error
-}
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.errors.txt b/tests/baselines/reference/objectSpreadIndexSignature.errors.txt
deleted file mode 100644
index d3faa2e6ff8f8..0000000000000
--- a/tests/baselines/reference/objectSpreadIndexSignature.errors.txt
+++ /dev/null
@@ -1,35 +0,0 @@
-tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts(6,39): error TS2699: Type literals with spreads cannot contain index, call or construct signatures.
-tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts(24,20): error TS2699: Type literals with spreads cannot contain index, call or construct signatures.
-
-
-==== tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts (2 errors) ====
-    class C {
-        a: number;
-        c: boolean;
-    }
-    // index signatures are not allowed in object literals with spread types
-    let c: { ...C, b: string, c?: string, [n: number]: string };
-                                          ~~~~~~~~~~~~~~~~~~~
-!!! error TS2699: Type literals with spreads cannot contain index, call or construct signatures.
-    let n: number = c.a;
-    let s: string = c[12];
-    interface Indexed {
-        [n: string]: number;
-        a: number;
-    }
-    let i: { ...Indexed, b: number };
-    n = i[101];
-    n = i.b;
-    interface Indexed2 {
-        [n: string]: boolean;
-        c: boolean;
-    }
-    let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
-    let nb: number | boolean = ii[1001];
-    
-    function f<T>(t: T) {
-        let i: { ...T, [n: number]: string };
-                       ~~~~~~~~~~~~~~~~~~~
-!!! error TS2699: Type literals with spreads cannot contain index, call or construct signatures.
-    }
-    
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.js b/tests/baselines/reference/objectSpreadIndexSignature.js
index ab18c0f24a942..22e92e6a844bf 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.js
+++ b/tests/baselines/reference/objectSpreadIndexSignature.js
@@ -1,46 +1,36 @@
 //// [objectSpreadIndexSignature.ts]
-class C {
-    a: number;
-    c: boolean;
-}
-// index signatures are not allowed in object literals with spread types
-let c: { ...C, b: string, c?: string, [n: number]: string };
-let n: number = c.a;
-let s: string = c[12];
 interface Indexed {
     [n: string]: number;
     a: number;
 }
-let i: { ...Indexed, b: number };
-n = i[101];
-n = i.b;
 interface Indexed2 {
     [n: string]: boolean;
     c: boolean;
 }
-let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
-let nb: number | boolean = ii[1001];
-
-function f<T>(t: T) {
-    let i: { ...T, [n: number]: string };
-}
+let indexed: Indexed;
+let indexed2: Indexed2;
+let i = { ...indexed, b: 11 };
+// only indexed has indexer, so i[101]: any
+i[101];
+let ii = { ...indexed, ...indexed2 };
+// both have indexer, so i[1001]: number | boolean
+ii[1001];
 
 
 //// [objectSpreadIndexSignature.js]
-var C = (function () {
-    function C() {
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
     }
-    return C;
-}());
-// index signatures are not allowed in object literals with spread types
-var c;
-var n = c.a;
-var s = c[12];
-var i;
-n = i[101];
-n = i.b;
-var ii;
-var nb = ii[1001];
-function f(t) {
-    var i;
-}
+    return t;
+};
+var indexed;
+var indexed2;
+var i = __assign({}, indexed, { b: 11 });
+// only indexed has indexer, so i[101]: any
+i[101];
+var ii = __assign({}, indexed, indexed2);
+// both have indexer, so i[1001]: number | boolean
+ii[1001];
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.symbols b/tests/baselines/reference/objectSpreadIndexSignature.symbols
new file mode 100644
index 0000000000000..c51e7f4532f98
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadIndexSignature.symbols
@@ -0,0 +1,42 @@
+=== tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts ===
+interface Indexed {
+>Indexed : Symbol(Indexed, Decl(objectSpreadIndexSignature.ts, 0, 0))
+
+    [n: string]: number;
+>n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 1, 5))
+
+    a: number;
+>a : Symbol(Indexed.a, Decl(objectSpreadIndexSignature.ts, 1, 24))
+}
+interface Indexed2 {
+>Indexed2 : Symbol(Indexed2, Decl(objectSpreadIndexSignature.ts, 3, 1))
+
+    [n: string]: boolean;
+>n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 5, 5))
+
+    c: boolean;
+>c : Symbol(Indexed2.c, Decl(objectSpreadIndexSignature.ts, 5, 25))
+}
+let indexed: Indexed;
+>indexed : Symbol(indexed, Decl(objectSpreadIndexSignature.ts, 8, 3))
+>Indexed : Symbol(Indexed, Decl(objectSpreadIndexSignature.ts, 0, 0))
+
+let indexed2: Indexed2;
+>indexed2 : Symbol(indexed2, Decl(objectSpreadIndexSignature.ts, 9, 3))
+>Indexed2 : Symbol(Indexed2, Decl(objectSpreadIndexSignature.ts, 3, 1))
+
+let i = { ...indexed, b: 11 };
+>i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 10, 3))
+>b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 10, 21))
+
+// only indexed has indexer, so i[101]: any
+i[101];
+>i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 10, 3))
+
+let ii = { ...indexed, ...indexed2 };
+>ii : Symbol(ii, Decl(objectSpreadIndexSignature.ts, 13, 3))
+
+// both have indexer, so i[1001]: number | boolean
+ii[1001];
+>ii : Symbol(ii, Decl(objectSpreadIndexSignature.ts, 13, 3))
+
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.types b/tests/baselines/reference/objectSpreadIndexSignature.types
new file mode 100644
index 0000000000000..79a515e73742d
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadIndexSignature.types
@@ -0,0 +1,52 @@
+=== tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts ===
+interface Indexed {
+>Indexed : Indexed
+
+    [n: string]: number;
+>n : string
+
+    a: number;
+>a : number
+}
+interface Indexed2 {
+>Indexed2 : Indexed2
+
+    [n: string]: boolean;
+>n : string
+
+    c: boolean;
+>c : boolean
+}
+let indexed: Indexed;
+>indexed : Indexed
+>Indexed : Indexed
+
+let indexed2: Indexed2;
+>indexed2 : Indexed2
+>Indexed2 : Indexed2
+
+let i = { ...indexed, b: 11 };
+>i : { b: number; a: number; }
+>{ ...indexed, b: 11 } : { b: number; a: number; }
+>indexed : any
+>b : number
+>11 : 11
+
+// only indexed has indexer, so i[101]: any
+i[101];
+>i[101] : any
+>i : { b: number; a: number; }
+>101 : 101
+
+let ii = { ...indexed, ...indexed2 };
+>ii : { [x: string]: number | boolean; c: boolean; a: number; }
+>{ ...indexed, ...indexed2 } : { [x: string]: number | boolean; c: boolean; a: number; }
+>indexed : any
+>indexed2 : any
+
+// both have indexer, so i[1001]: number | boolean
+ii[1001];
+>ii[1001] : number | boolean
+>ii : { [x: string]: number | boolean; c: boolean; a: number; }
+>1001 : 1001
+
diff --git a/tests/baselines/reference/objectSpreadNegative.errors.txt b/tests/baselines/reference/objectSpreadNegative.errors.txt
index 1af94007dc15e..dc6a356708f12 100644
--- a/tests/baselines/reference/objectSpreadNegative.errors.txt
+++ b/tests/baselines/reference/objectSpreadNegative.errors.txt
@@ -1,30 +1,26 @@
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(11,21): error TS2339: Property 'x' does not exist on type '{}'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(14,5): error TS2322: Type '{ sn?: string | number; }' is not assignable to type '{ sn: string | number; }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(13,21): error TS2339: Property 'x' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(16,5): error TS2322: Type '{ sn?: string | number; }' is not assignable to type '{ sn: string | number; }'.
   Property 'sn' is optional in type '{ sn?: string | number; }' but required in type '{ sn: string | number; }'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(20,5): error TS2322: Type '{ s: string; }' is not assignable to type '{ s: string; b: boolean; }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(23,1): error TS2322: Type '{ s: string; }' is not assignable to type '{ s: string; b: boolean; }'.
   Property 'b' is missing in type '{ s: string; }'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(22,1): error TS2322: Type 'Bool' is not assignable to type '{ s: string; b: boolean; }'.
-  Property 's' is missing in type 'Bool'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(25,36): error TS2300: Duplicate identifier 'b'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(25,53): error TS2300: Duplicate identifier 'b'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(30,12): error TS2339: Property 'null' does not exist on type '{}'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(32,17): error TS2339: Property 'undefined' does not exist on type '{}'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(36,11): error TS2339: Property 'toFixed' does not exist on type '{}'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(38,11): error TS2339: Property 'toFixed' does not exist on type '{}'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(40,11): error TS2339: Property 'length' does not exist on type '{}'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(41,11): error TS2339: Property 'charAt' does not exist on type '{}'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(45,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{}' has no compatible call signatures.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(49,12): error TS2339: Property 'b' does not exist on type '{}'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(55,9): error TS2339: Property 'm' does not exist on type '{ p: number; }'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(57,48): error TS2699: Type literals with spreads cannot contain index, call or construct signatures.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(57,69): error TS2699: Type literals with spreads cannot contain index, call or construct signatures.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(58,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ x: number; }' has no compatible call signatures.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(59,1): error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(64,9): error TS2322: Type '{ ...T & V }' is not assignable to type '{ ...T & U }'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(66,12): error TS2322: Type '{ ...U }' is not assignable to type 'U'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(25,1): error TS2322: Type '{ b: boolean; }' is not assignable to type '{ s: string; b: boolean; }'.
+  Property 's' is missing in type '{ b: boolean; }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(28,36): error TS2300: Duplicate identifier 'b'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(28,53): error TS2300: Duplicate identifier 'b'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(32,20): error TS2698: Spread types may only be created from object types.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(33,24): error TS2698: Spread types may only be created from object types.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(34,19): error TS2698: Spread types may only be created from object types.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(35,19): error TS2698: Spread types may only be created from object types.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(37,20): error TS2698: Spread types may only be created from object types.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(39,19): error TS2698: Spread types may only be created from object types.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(44,1): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{}' has no compatible call signatures.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(48,12): error TS2339: Property 'b' does not exist on type '{}'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(54,9): error TS2339: Property 'm' does not exist on type '{ p: number; }'.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(58,14): error TS2698: Spread types may only be created from object types.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(61,14): error TS2698: Spread types may only be created from object types.
 
 
-==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (21 errors) ====
+==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (17 errors) ====
     let o = { a: 1, b: 'no' }
     
     /// private propagates
@@ -34,7 +30,9 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(66,12): error TS232
     class PublicX {
         public x: number;
     }
-    let o2: { ...PublicX, ...PrivateOptionalX };
+    let publicX: PublicX;
+    let privateOptionalX: PrivateOptionalX;
+    let o2 = { ...publicX, ...privateOptionalX };
     let sn: number = o2.x; // error, x is private
                         ~
 !!! error TS2339: Property 'x' does not exist on type '{}'.
@@ -49,15 +47,16 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(66,12): error TS232
     // assignability as target
     interface Bool { b: boolean };
     interface Str { s: string };
-    let spread: { ...Bool, ...Str } = { s: 'foo' }; // error, missing 'b'
-        ~~~~~~
+    let spread = { ...{ b: true }, ...{s: "foo" } };
+    spread = { s: "foo" };  // error, missing 'b'
+    ~~~~~~
 !!! error TS2322: Type '{ s: string; }' is not assignable to type '{ s: string; b: boolean; }'.
 !!! error TS2322:   Property 'b' is missing in type '{ s: string; }'.
-    let b: Bool;
+    let b = { b: false };
     spread = b; // error, missing 's'
     ~~~~~~
-!!! error TS2322: Type 'Bool' is not assignable to type '{ s: string; b: boolean; }'.
-!!! error TS2322:   Property 's' is missing in type 'Bool'.
+!!! error TS2322: Type '{ b: boolean; }' is not assignable to type '{ s: string; b: boolean; }'.
+!!! error TS2322:   Property 's' is missing in type '{ b: boolean; }'.
     
     // literal repeats are not allowed, but spread repeats are fine
     let duplicated = { b: 'bad', ...o, b: 'bad', ...o2, b: 'bad' }
@@ -67,34 +66,30 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(66,12): error TS232
 !!! error TS2300: Duplicate identifier 'b'.
     let duplicatedSpread = { ...o, ...o }
     
-    // null and undefined are just skipped
-    let spreadNull = { ...null }
-    spreadNull.null;
-               ~~~~
-!!! error TS2339: Property 'null' does not exist on type '{}'.
-    let spreadUndefined = { ...undefined }
-    spreadUndefined.undefined;
-                    ~~~~~~~~~
-!!! error TS2339: Property 'undefined' does not exist on type '{}'.
-    
-    // primitives and functions are skipped
+    // null, undefined and primitives are not allowed
+    let spreadNull = { ...null };
+                       ~~~~~~~
+!!! error TS2698: Spread types may only be created from object types.
+    let spreadUndefind = { ...undefined };
+                           ~~~~~~~~~~~~
+!!! error TS2698: Spread types may only be created from object types.
     let spreadNum = { ...12 };
-    spreadNum.toFixed(); // error, no methods from number
-              ~~~~~~~
-!!! error TS2339: Property 'toFixed' does not exist on type '{}'.
+                      ~~~~~
+!!! error TS2698: Spread types may only be created from object types.
     let spreadSum = { ...1 + 1 };
+                      ~~~~~~~~
+!!! error TS2698: Spread types may only be created from object types.
     spreadSum.toFixed(); // error, no methods from number
-              ~~~~~~~
-!!! error TS2339: Property 'toFixed' does not exist on type '{}'.
+    let spreadBool = { ...false };
+                       ~~~~~~~~
+!!! error TS2698: Spread types may only be created from object types.
+    spreadBool.valueOf(); // error, what were you thinking?
     let spreadStr = { ...'foo' };
+                      ~~~~~~~~
+!!! error TS2698: Spread types may only be created from object types.
     spreadStr.length; // error, no 'length'
-              ~~~~~~
-!!! error TS2339: Property 'length' does not exist on type '{}'.
     spreadStr.charAt(1); // error, no methods either
-              ~~~~~~
-!!! error TS2339: Property 'charAt' does not exist on type '{}'.
-    let spreadBool = { ...true };
-    spreadBool.valueOf(); // error, what were you thinking?
+    // functions are skipped
     let spreadFunc = { ...function () { } }
     spreadFunc(); // error, no call signature
     ~~~~~~~~~~~~
@@ -114,27 +109,23 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(66,12): error TS232
             ~
 !!! error TS2339: Property 'm' does not exist on type '{ p: number; }'.
     
-    let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: number) };
-                                                   ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2699: Type literals with spreads cannot contain index, call or construct signatures.
-                                                                        ~~~~~~~~~~~~~~~
-!!! error TS2699: Type literals with spreads cannot contain index, call or construct signatures.
-    callableConstructableSpread(12); // error, no call signature
-    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2349: Cannot invoke an expression whose type lacks a call signature. Type '{ x: number; }' has no compatible call signatures.
-    new callableConstructableSpread(12); // error, no construct signature
-    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
-    
-    function override<T,U,V>(initial: U, override: U, t: T, v: V): U {
-        // { ... T & V } is not assignable to { ... T & U }
-        let tvs: { ...T & V };
-        let mistake: { ...T & U } = tvs;
-            ~~~~~~~
-!!! error TS2322: Type '{ ...T & V }' is not assignable to type '{ ...T & U }'.
-        // { ...U } is not assignable to U
+    // generics
+    function f<T, U>(t: T, u: U) {
+        return { ...t, ...u, id: 'id' };
+                 ~~~~
+!!! error TS2698: Spread types may only be created from object types.
+    }
+    function override<U>(initial: U, override: U): U {
         return { ...initial, ...override };
-               ~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2322: Type '{ ...U }' is not assignable to type 'U'.
+                 ~~~~~~~~~~
+!!! error TS2698: Spread types may only be created from object types.
     }
+    let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
+        f({ a: 1, b: 'yes' }, { c: 'no', d: false })
+    let overlap: { id: string, a: number, b: string } =
+        f({ a: 1 }, { a: 2, b: 'extra' })
+    let overlapConflict: { id:string, a: string } =
+        f({ a: 1 }, { a: 'mismatch' })
+    let overwriteId: { id: string, a: number, c: number, d: string } =
+        f({ a: 1, id: true }, { c: 1, d: 'no' })
     
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadNegative.js b/tests/baselines/reference/objectSpreadNegative.js
index 7187b6009bd39..4faacd9744450 100644
--- a/tests/baselines/reference/objectSpreadNegative.js
+++ b/tests/baselines/reference/objectSpreadNegative.js
@@ -8,7 +8,9 @@ class PrivateOptionalX {
 class PublicX {
     public x: number;
 }
-let o2: { ...PublicX, ...PrivateOptionalX };
+let publicX: PublicX;
+let privateOptionalX: PrivateOptionalX;
+let o2 = { ...publicX, ...privateOptionalX };
 let sn: number = o2.x; // error, x is private
 let optionalString: { sn?: string };
 let optionalNumber: { sn?: number };
@@ -18,30 +20,27 @@ let allOptional: { sn: string | number } = { ...optionalString, ...optionalNumbe
 // assignability as target
 interface Bool { b: boolean };
 interface Str { s: string };
-let spread: { ...Bool, ...Str } = { s: 'foo' }; // error, missing 'b'
-let b: Bool;
+let spread = { ...{ b: true }, ...{s: "foo" } };
+spread = { s: "foo" };  // error, missing 'b'
+let b = { b: false };
 spread = b; // error, missing 's'
 
 // literal repeats are not allowed, but spread repeats are fine
 let duplicated = { b: 'bad', ...o, b: 'bad', ...o2, b: 'bad' }
 let duplicatedSpread = { ...o, ...o }
 
-// null and undefined are just skipped
-let spreadNull = { ...null }
-spreadNull.null;
-let spreadUndefined = { ...undefined }
-spreadUndefined.undefined;
-
-// primitives and functions are skipped
+// null, undefined and primitives are not allowed
+let spreadNull = { ...null };
+let spreadUndefind = { ...undefined };
 let spreadNum = { ...12 };
-spreadNum.toFixed(); // error, no methods from number
 let spreadSum = { ...1 + 1 };
 spreadSum.toFixed(); // error, no methods from number
+let spreadBool = { ...false };
+spreadBool.valueOf(); // error, what were you thinking?
 let spreadStr = { ...'foo' };
 spreadStr.length; // error, no 'length'
 spreadStr.charAt(1); // error, no methods either
-let spreadBool = { ...true };
-spreadBool.valueOf(); // error, what were you thinking?
+// functions are skipped
 let spreadFunc = { ...function () { } }
 spreadFunc(); // error, no call signature
 
@@ -55,17 +54,21 @@ let c: C = new C()
 let spreadC = { ...c }
 spreadC.m(); // error 'm' is not in '{ ... c }'
 
-let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: number) };
-callableConstructableSpread(12); // error, no call signature
-new callableConstructableSpread(12); // error, no construct signature
-
-function override<T,U,V>(initial: U, override: U, t: T, v: V): U {
-    // { ... T & V } is not assignable to { ... T & U }
-    let tvs: { ...T & V };
-    let mistake: { ...T & U } = tvs;
-    // { ...U } is not assignable to U
+// generics
+function f<T, U>(t: T, u: U) {
+    return { ...t, ...u, id: 'id' };
+}
+function override<U>(initial: U, override: U): U {
     return { ...initial, ...override };
 }
+let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
+    f({ a: 1, b: 'yes' }, { c: 'no', d: false })
+let overlap: { id: string, a: number, b: string } =
+    f({ a: 1 }, { a: 2, b: 'extra' })
+let overlapConflict: { id:string, a: string } =
+    f({ a: 1 }, { a: 'mismatch' })
+let overwriteId: { id: string, a: number, c: number, d: string } =
+    f({ a: 1, id: true }, { c: 1, d: 'no' })
 
 
 //// [objectSpreadNegative.js]
@@ -89,34 +92,34 @@ var PublicX = (function () {
     }
     return PublicX;
 }());
-var o2;
+var publicX;
+var privateOptionalX;
+var o2 = __assign({}, publicX, privateOptionalX);
 var sn = o2.x; // error, x is private
 var optionalString;
 var optionalNumber;
 var allOptional = __assign({}, optionalString, optionalNumber);
 ;
 ;
-var spread = { s: 'foo' }; // error, missing 'b'
-var b;
+var spread = __assign({ b: true }, { s: "foo" });
+spread = { s: "foo" }; // error, missing 'b'
+var b = { b: false };
 spread = b; // error, missing 's'
 // literal repeats are not allowed, but spread repeats are fine
 var duplicated = __assign({ b: 'bad' }, o, { b: 'bad' }, o2, { b: 'bad' });
 var duplicatedSpread = __assign({}, o, o);
-// null and undefined are just skipped
+// null, undefined and primitives are not allowed
 var spreadNull = __assign({}, null);
-spreadNull.null;
-var spreadUndefined = __assign({}, undefined);
-spreadUndefined.undefined;
-// primitives and functions are skipped
+var spreadUndefind = __assign({}, undefined);
 var spreadNum = __assign({}, 12);
-spreadNum.toFixed(); // error, no methods from number
 var spreadSum = __assign({}, 1 + 1);
 spreadSum.toFixed(); // error, no methods from number
+var spreadBool = __assign({}, false);
+spreadBool.valueOf(); // error, what were you thinking?
 var spreadStr = __assign({}, 'foo');
 spreadStr.length; // error, no 'length'
 spreadStr.charAt(1); // error, no methods either
-var spreadBool = __assign({}, true);
-spreadBool.valueOf(); // error, what were you thinking?
+// functions are skipped
 var spreadFunc = __assign({}, function () { });
 spreadFunc(); // error, no call signature
 // write-only properties get skipped
@@ -133,13 +136,14 @@ var C = (function () {
 var c = new C();
 var spreadC = __assign({}, c);
 spreadC.m(); // error 'm' is not in '{ ... c }'
-var callableConstructableSpread;
-callableConstructableSpread(12); // error, no call signature
-new callableConstructableSpread(12); // error, no construct signature
-function override(initial, override, t, v) {
-    // { ... T & V } is not assignable to { ... T & U }
-    var tvs;
-    var mistake = tvs;
-    // { ...U } is not assignable to U
+// generics
+function f(t, u) {
+    return __assign({}, t, u, { id: 'id' });
+}
+function override(initial, override) {
     return __assign({}, initial, override);
 }
+var exclusive = f({ a: 1, b: 'yes' }, { c: 'no', d: false });
+var overlap = f({ a: 1 }, { a: 2, b: 'extra' });
+var overlapConflict = f({ a: 1 }, { a: 'mismatch' });
+var overwriteId = f({ a: 1, id: true }, { c: 1, d: 'no' });
diff --git a/tests/baselines/reference/objectSpreadNegativeParse.errors.txt b/tests/baselines/reference/objectSpreadNegativeParse.errors.txt
index 41651fb1d1c8e..987172ef867bf 100644
--- a/tests/baselines/reference/objectSpreadNegativeParse.errors.txt
+++ b/tests/baselines/reference/objectSpreadNegativeParse.errors.txt
@@ -1,26 +1,36 @@
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(1,12): error TS2698: Spread types may only be created from object types.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(1,15): error TS2304: Cannot find name 'o'.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(1,18): error TS1109: Expression expected.
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(2,12): error TS2698: Spread types may only be created from object types.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(2,15): error TS1109: Expression expected.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(2,16): error TS2304: Cannot find name 'o'.
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(3,12): error TS2698: Spread types may only be created from object types.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(3,15): error TS2304: Cannot find name 'matchMedia'.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(3,28): error TS1005: ',' expected.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(3,31): error TS1128: Declaration or statement expected.
+tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(4,13): error TS2698: Spread types may only be created from object types.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(4,16): error TS2304: Cannot find name 'get'.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(4,20): error TS1005: ',' expected.
 
 
-==== tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts (9 errors) ====
+==== tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts (13 errors) ====
     let o7 = { ...o? };
+               ~~~~~
+!!! error TS2698: Spread types may only be created from object types.
                   ~
 !!! error TS2304: Cannot find name 'o'.
                      ~
 !!! error TS1109: Expression expected.
     let o8 = { ...*o };
+               ~~~~~
+!!! error TS2698: Spread types may only be created from object types.
                   ~
 !!! error TS1109: Expression expected.
                    ~
 !!! error TS2304: Cannot find name 'o'.
     let o9 = { ...matchMedia() { }};
+               ~~~~~~~~~~~~~~~
+!!! error TS2698: Spread types may only be created from object types.
                   ~~~~~~~~~~
 !!! error TS2304: Cannot find name 'matchMedia'.
                                ~
@@ -28,6 +38,8 @@ tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(4,20): error T
                                   ~
 !!! error TS1128: Declaration or statement expected.
     let o10 = { ...get x() { return 12; }};
+                ~~~~~~
+!!! error TS2698: Spread types may only be created from object types.
                    ~~~
 !!! error TS2304: Cannot find name 'get'.
                        ~
diff --git a/tests/cases/conformance/types/spread/interfaceSpread.ts b/tests/cases/conformance/types/spread/interfaceSpread.ts
deleted file mode 100644
index a92a188e1a884..0000000000000
--- a/tests/cases/conformance/types/spread/interfaceSpread.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-interface Congealed<T, U> {
-    ...T
-    ...U
-}
-
-let sandwich: Congealed<{jam: number }, { peanutButter: number }>;
-sandwich.jam;
-sandwich.peanutButter;
diff --git a/tests/cases/conformance/types/spread/objectSpread.ts b/tests/cases/conformance/types/spread/objectSpread.ts
index daadb1e3270e5..3336196e136c3 100644
--- a/tests/cases/conformance/types/spread/objectSpread.ts
+++ b/tests/cases/conformance/types/spread/objectSpread.ts
@@ -35,13 +35,8 @@ let getter: { a: number, c: number } =
     { ...op, c: 7 }
 getter.a = 12;
 
-// null, undefined, functions and primitives result in { }
-let spreadNull = { ...null };
-let spreadUndefind = { ...undefined };
-let spreadNum = { ...12 };
-let spreadBool = { ...false };
+// functions result in { }
 let spreadFunc = { ...(function () { }) };
-let spreadStr = { ...'foo' };
 
 // methods are not enumerable
 class C { p = 1; m() { } }
@@ -80,19 +75,3 @@ let computedAfter: { a: number, b: string, "at the end": number } =
 let a = 12;
 let shortCutted: { a: number, b: string } = { ...o, a }
 
-// generics
-function f<T, U>(t: T, u: U): { ...T, ...U, id: string } {
-    return { ...t, ...u, id: 'id' };
-}
-let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
-    f({ a: 1, b: 'yes' }, { c: 'no', d: false })
-let overlap: { id: string, a: number, b: string } =
-    f({ a: 1 }, { a: 2, b: 'extra' })
-let overlapConflict: { id:string, a: string } =
-    f({ a: 1 }, { a: 'mismatch' })
-let overwriteId: { id: string, a: number, c: number, d: string } =
-    f({ a: 1, id: true }, { c: 1, d: 'no' })
-
-class D { m() { }; q = 2; }
-let classesAreWrong: { id: string, ...C, ...D } =
-    f(new C(), new D())
diff --git a/tests/cases/conformance/types/spread/objectSpreadGeneric.ts b/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
deleted file mode 100644
index 6f22358b7e25a..0000000000000
--- a/tests/cases/conformance/types/spread/objectSpreadGeneric.ts
+++ /dev/null
@@ -1,72 +0,0 @@
-function f<T, U, V>(t: T, u: U, v: V): void {
-    let o: { ...T, ...U, ...V };
-    let uus: { ...U, ...U};
-    let us: { ...U };
-    const same: { ...T, ...U, ...V } = o; // ok
-    uus = us; // ok, multiple spreads are equivalent to a single one
-    us = uus; // ok, multiple spreads are equivalent to a single one
-    us = u;   // ok, type has at least all the properties of the spread
-    u = us;   // error, might be missing a ton of stuff
-    const reversed: { ...V, ...U, ...T } = o; // error, reversed
-    const reversed2: { ...U, ...T, ...V } = o; // error, U and T are still reversed
-    const missingT: { ...U, ...V } = o; // error, missing T
-    const missingU: { ...T, ...V } = o; // error, missing U
-    const missingV: { ...T, ...U } = o; // error, missing V
-    const atEnd: { ...T, ...U, second: string } = { ...t, ...u, second: 'foo' }; // ok
-    const atBeginning: { first: string, ...T, ...U, } = { first: 'foo', ...t, ...u }; // error, not assignable
-
-    const emptyTarget: { } = { ...t, ...u } // ok
-    const emptySource: { ...T, ...U } = { }; // error, {} is not assignable to U (or T)
-
-    // error, { sn?: boolean } ...T ... { sn?: number | string } is not assignable to
-    //        T ... { sn?: number | string | boolean }
-    let optionalNumber: { sn?: number };
-    let optionalString: { sn?: string };
-    let optionalBoolean: { sn?: boolean };
-    const unionCutoff: { ...T, sn?: number | string | boolean } =
-        { ...optionalBoolean, ...t, ...optionalString, ...optionalNumber }
-    unionCutoff.sn; // ok
-    const optionalCutoff = { ...t, ...optionalNumber }; // ok
-    optionalCutoff.sn; // ok
-
-    const interspersed: { first: string, ...T, second: string, ...U, third: string } =
-        { first: '1', ...t, second: '2', ...u, third: '3' }; // error, not assignable
-    const interspersedMissingU: { first: string, second: string, ...T, third: string } =
-        { first: '1', ...t, second: '2', ...u, third: '3' }; // error, 'U' is missing
-    const interspersedOrder1: { first: string, ...T, second: string, ...U, third: string, secondsecond: string } =
-        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // error, not assignable
-    const interspersedOrder2: { first: string, second: string, secondsecond: string, third: string, ...T, ...U } =
-        { first: '1', ...t, second: '2', ...u, third: '3', secondsecond: 'false' }; // error, not assignable
-
-
-    const mismatchFirst: { first: string, ...T, second: string, ...U, third: string } =
-        { firrrrrrst: '1', ...t, second: '2', ...u, third: '3' }; // error, not assignable
-    const mismatchSecond: { first: string, ...T, second: string, ...U, third: string } =
-        { first: '1', ...t, ssssssssecond: '2', ...u, third: '3' }; // error, not assignable
-    const mismatchLast: { first: string, ...T, second: string, ...U, third: string } =
-        { first: '1', ...t, second: '2', ...u, thirrrrrrrd: '3' }; // error, not assignable
-}
-
-function indexAccessedTest<T, K extends keyof T, U, J extends keyof U>(t: T, u: U, key1: K, key2: J) {
-    let k1: { ...keyof T };
-    let k2: { ...keyof U };
-    let k3: { ...K };
-    let k4: { ...J };
-    k1 = k1; // ok
-    k2 = k2; // ok
-    k1 = k2; // error
-    k2 = k1; // error
-    k3 = k3; // ok
-    k4 = k4; // ok
-    k1 = k3; // error
-    k3 = k1; // error
-    k2 = k4; // error
-    k4 = k2; // error
-
-    let i1: { ...T[K] };
-    let i2: { ...U[J] };
-    i1 = i1; // ok
-    i2 = i2; // ok
-    i1 = i2; // error
-    i2 = i1; // error
-}
diff --git a/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts b/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
index 8c9194d2d4cdc..ae46f2547d54c 100644
--- a/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
@@ -1,25 +1,16 @@
-class C {
-    a: number;
-    c: boolean;
-}
-// index signatures are not allowed in object literals with spread types
-let c: { ...C, b: string, c?: string, [n: number]: string };
-let n: number = c.a;
-let s: string = c[12];
 interface Indexed {
     [n: string]: number;
     a: number;
 }
-let i: { ...Indexed, b: number };
-n = i[101];
-n = i.b;
 interface Indexed2 {
     [n: string]: boolean;
     c: boolean;
 }
-let ii: { ...Indexed, ...Indexed2, b: boolean, d: number };
-let nb: number | boolean = ii[1001];
-
-function f<T>(t: T) {
-    let i: { ...T, [n: number]: string };
-}
+let indexed: Indexed;
+let indexed2: Indexed2;
+let i = { ...indexed, b: 11 };
+// only indexed has indexer, so i[101]: any
+i[101];
+let ii = { ...indexed, ...indexed2 };
+// both have indexer, so i[1001]: number | boolean
+ii[1001];
diff --git a/tests/cases/conformance/types/spread/objectSpreadInference.ts b/tests/cases/conformance/types/spread/objectSpreadInference.ts
deleted file mode 100644
index 9608f0a16cb95..0000000000000
--- a/tests/cases/conformance/types/spread/objectSpreadInference.ts
+++ /dev/null
@@ -1,19 +0,0 @@
-interface Result<T,U,V> {
-    t: T;
-    u: U;
-    v: V;
-}
-declare function infer<T,U,V>(tuv: { ...T, ...U, a: V }): { t: T, u: U, v: V };
-declare function infer2<T,U,V>(utv: { ...U, a: V, ...T }): { t: T, u: U, v: V };
-function generic<W, X, Y>(w: W, x: X, y: Y) {
-    // should infer { t: {}, u: {}, v: {} } because there is no trailing type parameter
-    return infer({ ...w, ...x, a: y, b: "different type" });
-}
-let b: { b: number };
-let c: { c: number };
-// can only infer { t: {}, u: {}, v: {} }
-let i1 = infer({ ...b, ...c, a: 12 });
-// can only infer { t: {}, u: {}, v: {} }
-let i2 = infer2({ ...b, ...c, a: 12 });
-// can only infer { t: {}, u: {}, v: {} }
-let i3 = generic(b, c, { a: 12 });
diff --git a/tests/cases/conformance/types/spread/objectSpreadIntersection.ts b/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
deleted file mode 100644
index 3bedacca89fac..0000000000000
--- a/tests/cases/conformance/types/spread/objectSpreadIntersection.ts
+++ /dev/null
@@ -1,36 +0,0 @@
-function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
-    let tu: T | U;
-    let uv: U & V;
-    let result = { ...tu, ...uv, id: 'foo' };
-    let assignable: { ...(T | U), ...(U & V), id: string } = result;
-}
-// concrete types work
-interface A1 { a: number }
-interface A2 { a: string }
-interface B1 { b: number }
-interface B2 { b: string }
-let a12: A1 & A2;
-let b12: B1 & B2;
-let result = { ...a12, ...b12 };
-let sn: number & string = result.a;
-sn = result.b;
-let assignable: { ...(A1 & A2), ...(B1 & B2) } = result;
-
-function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
-    let tuv: T & U & V;
-    let result = { ...tuv, id: 'bar' };
-    let assignable: { ...(T & U & V), id: string } = result;
-}
-function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
-    let tu: T & U;
-    let uv: U & V;
-    let result = { ...tu, ...uv, id: 'baz' };
-    let assignable: { ...(T & U), ...(U & V), id: string } = result;
-}
-function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
-    let tu: T & U;
-    let uv: U | V;
-    let result = { ...tu, ...uv, id: 'qux' };
-    let assignable: { ...(T & U), ...(U | V), id: string } = result;
-}
-
diff --git a/tests/cases/conformance/types/spread/objectSpreadNegative.ts b/tests/cases/conformance/types/spread/objectSpreadNegative.ts
index 146ab072bbf17..3cd819d061350 100644
--- a/tests/cases/conformance/types/spread/objectSpreadNegative.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadNegative.ts
@@ -8,7 +8,9 @@ class PrivateOptionalX {
 class PublicX {
     public x: number;
 }
-let o2: { ...PublicX, ...PrivateOptionalX };
+let publicX: PublicX;
+let privateOptionalX: PrivateOptionalX;
+let o2 = { ...publicX, ...privateOptionalX };
 let sn: number = o2.x; // error, x is private
 let optionalString: { sn?: string };
 let optionalNumber: { sn?: number };
@@ -18,30 +20,27 @@ let allOptional: { sn: string | number } = { ...optionalString, ...optionalNumbe
 // assignability as target
 interface Bool { b: boolean };
 interface Str { s: string };
-let spread: { ...Bool, ...Str } = { s: 'foo' }; // error, missing 'b'
-let b: Bool;
+let spread = { ...{ b: true }, ...{s: "foo" } };
+spread = { s: "foo" };  // error, missing 'b'
+let b = { b: false };
 spread = b; // error, missing 's'
 
 // literal repeats are not allowed, but spread repeats are fine
 let duplicated = { b: 'bad', ...o, b: 'bad', ...o2, b: 'bad' }
 let duplicatedSpread = { ...o, ...o }
 
-// null and undefined are just skipped
-let spreadNull = { ...null }
-spreadNull.null;
-let spreadUndefined = { ...undefined }
-spreadUndefined.undefined;
-
-// primitives and functions are skipped
+// null, undefined and primitives are not allowed
+let spreadNull = { ...null };
+let spreadUndefind = { ...undefined };
 let spreadNum = { ...12 };
-spreadNum.toFixed(); // error, no methods from number
 let spreadSum = { ...1 + 1 };
 spreadSum.toFixed(); // error, no methods from number
+let spreadBool = { ...false };
+spreadBool.valueOf(); // error, what were you thinking?
 let spreadStr = { ...'foo' };
 spreadStr.length; // error, no 'length'
 spreadStr.charAt(1); // error, no methods either
-let spreadBool = { ...true };
-spreadBool.valueOf(); // error, what were you thinking?
+// functions are skipped
 let spreadFunc = { ...function () { } }
 spreadFunc(); // error, no call signature
 
@@ -55,14 +54,18 @@ let c: C = new C()
 let spreadC = { ...c }
 spreadC.m(); // error 'm' is not in '{ ... c }'
 
-let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: number) };
-callableConstructableSpread(12); // error, no call signature
-new callableConstructableSpread(12); // error, no construct signature
-
-function override<T,U,V>(initial: U, override: U, t: T, v: V): U {
-    // { ... T & V } is not assignable to { ... T & U }
-    let tvs: { ...T & V };
-    let mistake: { ...T & U } = tvs;
-    // { ...U } is not assignable to U
+// generics
+function f<T, U>(t: T, u: U) {
+    return { ...t, ...u, id: 'id' };
+}
+function override<U>(initial: U, override: U): U {
     return { ...initial, ...override };
 }
+let exclusive: { id: string, a: number, b: string, c: string, d: boolean } =
+    f({ a: 1, b: 'yes' }, { c: 'no', d: false })
+let overlap: { id: string, a: number, b: string } =
+    f({ a: 1 }, { a: 2, b: 'extra' })
+let overlapConflict: { id:string, a: string } =
+    f({ a: 1 }, { a: 'mismatch' })
+let overwriteId: { id: string, a: number, c: number, d: string } =
+    f({ a: 1, id: true }, { c: 1, d: 'no' })
diff --git a/tests/cases/conformance/types/spread/objectSpreadScenarios.ts b/tests/cases/conformance/types/spread/objectSpreadScenarios.ts
deleted file mode 100644
index 1db930cb71c51..0000000000000
--- a/tests/cases/conformance/types/spread/objectSpreadScenarios.ts
+++ /dev/null
@@ -1,17 +0,0 @@
-interface A1 { a: boolean }
-interface B1 { b: number };
-function override<U>(initial: U, override: U): { ...U, ...U } {
-    return { ...initial, ...override };
-}
-function update<U>(this: { u: { ...U } }, override: U): void {
-    this.u = { ...this.u, ...override };
-}
-function mixin<T, U>(one: T, two: U): { ...T, ...U } {
-    return { ...one, ...two };
-}
-let a1: A1 = { a: true };
-let b1: B1 = { b: 101 };
-a1 = override(a1, { a: false });
-let host = { u: a1, update };
-host.update({ a: false });
-let mixed = mixin(a1, b1);
diff --git a/tests/cases/conformance/types/spread/objectSpreadUnion.ts b/tests/cases/conformance/types/spread/objectSpreadUnion.ts
deleted file mode 100644
index cd490d76bdaf4..0000000000000
--- a/tests/cases/conformance/types/spread/objectSpreadUnion.ts
+++ /dev/null
@@ -1,23 +0,0 @@
-// concrete types work
-interface A1 { a: number }
-interface A2 { a: string }
-let a12: A1 | A2;
-let result = { ...a12 };
-let sn: number | string = result.a;
-let assignable: { ...(A1 | A2) } = result;
-
-function tripleUnion<T, U, V>(t: T, u: U, v: V): void {
-    let tuv: T | U | V;
-    let result = { ...tuv, id: 'foo' };
-    let expected: { ...T, id: string } | { ...U, id: string } | { ...V, id: string } = result;
-    let assignable: { ...(T | U | V), id: string } = result;
-}
-function iteratedDoubleUnion<T, U, V>(t: T, u: U, v: V): void {
-    let tu: T | U;
-    let uv: U | V;
-    let result = { ...tu, ...uv, id: 'bar' };
-    let expected: { ...T, ...U, id: string } | { ...T, ...V, id: string } | { ...U, id: string } | { ...U, ...V, id: string };
-    let assignable: { ...(T | U), ...(U | V), id: string } = result;
-}
-
-
diff --git a/tests/cases/fourslash/findAllRefsForObjectSpread.ts b/tests/cases/fourslash/findAllRefsForObjectSpread.ts
index 650324a5d8467..05c83491f6651 100644
--- a/tests/cases/fourslash/findAllRefsForObjectSpread.ts
+++ b/tests/cases/fourslash/findAllRefsForObjectSpread.ts
@@ -2,7 +2,9 @@
 
 ////interface A1 { [|a|]: string };
 ////interface A2 { [|a|]?: number };
-////let a12: { ...A1, ...A2 };
+////let a1: A1;
+////let a2: A2;
+////let a12 = { ...a1, ...a2 };
 ////a12.[|a|];
 const ranges = test.ranges();
 // members of spread types only refer to themselves and the resulting property
diff --git a/tests/cases/fourslash/goToDefinitionObjectSpread.ts b/tests/cases/fourslash/goToDefinitionObjectSpread.ts
index 64623c36cb76b..b23d0a8044832 100644
--- a/tests/cases/fourslash/goToDefinitionObjectSpread.ts
+++ b/tests/cases/fourslash/goToDefinitionObjectSpread.ts
@@ -2,6 +2,8 @@
 
 ////interface A1 { /*1*/a: number };
 ////interface A2 { /*2*/a?: number };
-////let a12: { ...A1, ...A2 };
+////let a1: A1;
+////let a2: A2;
+////let a12 = { ...a1, ...a2 };
 ////a12.a/*3*/;
 verify.goToDefinition('3', [ '1', '2' ]);
diff --git a/tests/cases/fourslash/renameObjectSpread.ts b/tests/cases/fourslash/renameObjectSpread.ts
index a2c640361e59c..eba148c0e3944 100644
--- a/tests/cases/fourslash/renameObjectSpread.ts
+++ b/tests/cases/fourslash/renameObjectSpread.ts
@@ -2,7 +2,9 @@
 
 ////interface A1 { [|a|]: number };
 ////interface A2 { [|a|]?: number };
-////let a12: { ...A1, ...A2 };
+////let a1: A1;
+////let a2: A2;
+////let a12 = { ...a1, ...a2 };
 ////a12.[|a|];
 const ranges = test.ranges();
 verify.assertHasRanges(ranges);

From 7a2c7ad37420ad8f11652a6b87116c1b20fca802 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 3 Nov 2016 09:41:31 -0700
Subject: [PATCH 160/224] Spread handles index signatures from singleton
 spreads

I broke it when simplifying the logic earlier.
---
 src/compiler/checker.ts | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 872aad6b046b7..3475a9d52c6f7 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5888,8 +5888,17 @@ namespace ts {
             Debug.assert(!!(left.flags & TypeFlags.Object) && !!(right.flags & TypeFlags.Object), "Only object types may be spread.");
             const members = createMap<Symbol>();
             const skippedPrivateMembers = createMap<boolean>();
-            const stringIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.String), getIndexInfoOfType(right, IndexKind.String));
-            const numberIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.Number), getIndexInfoOfType(right, IndexKind.Number));
+            let stringIndexInfo: IndexInfo;
+            let numberIndexInfo: IndexInfo;
+            if (left === emptyObjectType) {
+                // for the first spread element, left === emptyObjectType, so take the right's string indexer
+                stringIndexInfo = getIndexInfoOfType(right, IndexKind.String);
+                numberIndexInfo = getIndexInfoOfType(right, IndexKind.Number);
+            }
+            else {
+                stringIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.String), getIndexInfoOfType(right, IndexKind.String));
+                numberIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.Number), getIndexInfoOfType(right, IndexKind.Number));
+            }
 
             const isFromSpread = right.symbol !== symbol;
             for (const rightProp of getPropertiesOfType(right)) {

From 83abd048b55f67e02e8fcbf69a9ed934056146bd Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 3 Nov 2016 10:01:27 -0700
Subject: [PATCH 161/224] Correct assignability for keyof types and type
 parameters

---
 src/compiler/checker.ts | 21 +++++++++++++++++++++
 src/compiler/types.ts   |  2 +-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 006b87cb542ee..b47f6264e3e9c 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -6825,6 +6825,27 @@ namespace ts {
                     }
                 }
 
+                if (target.flags & TypeFlags.TypeParameter) {
+                    // Given a type parameter K with a constraint keyof T, a type S is
+                    // assignable to K if S is assignable to keyof T.
+                    let constraint = getConstraintOfTypeParameter(<TypeParameter>target);
+                    if (constraint && constraint.flags & TypeFlags.Index) {
+                        if (result = isRelatedTo(source, constraint, reportErrors)) {
+                            return result;
+                        }
+                    }
+                }
+                else if (target.flags & TypeFlags.Index) {
+                    // Given a type parameter T with a constraint C, a type S is assignable to
+                    // keyof T if S is assignable to keyof C.
+                    let constraint = getConstraintOfTypeParameter((<IndexType>target).type);
+                    if (constraint) {
+                        if (result = isRelatedTo(source, getIndexType(constraint), reportErrors)) {
+                            return result;
+                        }
+                    }
+                }
+
                 if (source.flags & TypeFlags.TypeParameter) {
                     let constraint = getConstraintOfTypeParameter(<TypeParameter>source);
 
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index e4c92c502a456..b865beca76b9a 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2709,7 +2709,7 @@ namespace ts {
         EnumLike = Enum | EnumLiteral,
         UnionOrIntersection = Union | Intersection,
         StructuredType = Object | Union | Intersection,
-        StructuredOrTypeParameter = StructuredType | TypeParameter,
+        StructuredOrTypeParameter = StructuredType | TypeParameter | Index,
 
         // 'Narrowable' types are types where narrowing actually narrows.
         // This *should* be every type other than null, undefined, void, and never

From 4019265fe1bf8d7a0ef27fd1727304daff26c428 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 3 Nov 2016 10:01:42 -0700
Subject: [PATCH 162/224] Update tests

---
 .../types/keyof/keyofAndIndexedAccess.ts      | 47 +++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts b/tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts
index b63386a68a31e..1e874aaf80f8a 100644
--- a/tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts
+++ b/tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts
@@ -7,6 +7,10 @@ class Shape {
     visible: boolean;
 }
 
+class TaggedShape extends Shape {
+    tag: string;
+}
+
 class Item {
     name: string;
     price: number;
@@ -149,6 +153,17 @@ function f32<K extends "width" | "height">(key: K) {
     return shape[key];  // Shape[K]
 }
 
+function f33<S extends Shape, K extends keyof S>(shape: S, key: K) {
+    let name = getProperty(shape, "name");
+    let prop = getProperty(shape, key);
+    return prop;
+}
+
+function f34(ts: TaggedShape) {
+    let tag1 = f33(ts, "tag");
+    let tag2 = getProperty(ts, "tag");
+}
+
 class C {
     public x: string;
     protected y: string;
@@ -164,4 +179,36 @@ function f40(c: C) {
     let x: X = c["x"];
     let y: Y = c["y"];
     let z: Z = c["z"];
+}
+
+// Repros from #12011
+
+class Base {
+    get<K extends keyof this>(prop: K) {
+        return this[prop];
+    }
+    set<K extends keyof this>(prop: K, value: this[K]) {
+        this[prop] = value;
+    }
+}
+
+class Person extends Base {
+    parts: number;
+    constructor(parts: number) {
+        super();
+        this.set("parts", parts);
+    }
+    getParts() {
+        return this.get("parts")
+    }
+}
+
+class OtherPerson {
+    parts: number;
+    constructor(parts: number) {
+        setProperty(this, "parts", parts);
+    }
+    getParts() {
+        return getProperty(this, "parts")
+    }
 }
\ No newline at end of file

From d9b0b637e3b014de2462dde173904d05d1720790 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 3 Nov 2016 10:01:53 -0700
Subject: [PATCH 163/224] Accept new baselines

---
 .../reference/keyofAndIndexedAccess.js        | 120 +++
 .../reference/keyofAndIndexedAccess.symbols   | 712 +++++++++++-------
 .../reference/keyofAndIndexedAccess.types     | 151 ++++
 3 files changed, 693 insertions(+), 290 deletions(-)

diff --git a/tests/baselines/reference/keyofAndIndexedAccess.js b/tests/baselines/reference/keyofAndIndexedAccess.js
index 5d986f3e89203..dd59a5a1b4c72 100644
--- a/tests/baselines/reference/keyofAndIndexedAccess.js
+++ b/tests/baselines/reference/keyofAndIndexedAccess.js
@@ -7,6 +7,10 @@ class Shape {
     visible: boolean;
 }
 
+class TaggedShape extends Shape {
+    tag: string;
+}
+
 class Item {
     name: string;
     price: number;
@@ -149,6 +153,17 @@ function f32<K extends "width" | "height">(key: K) {
     return shape[key];  // Shape[K]
 }
 
+function f33<S extends Shape, K extends keyof S>(shape: S, key: K) {
+    let name = getProperty(shape, "name");
+    let prop = getProperty(shape, key);
+    return prop;
+}
+
+function f34(ts: TaggedShape) {
+    let tag1 = f33(ts, "tag");
+    let tag2 = getProperty(ts, "tag");
+}
+
 class C {
     public x: string;
     protected y: string;
@@ -164,14 +179,58 @@ function f40(c: C) {
     let x: X = c["x"];
     let y: Y = c["y"];
     let z: Z = c["z"];
+}
+
+// Repros from #12011
+
+class Base {
+    get<K extends keyof this>(prop: K) {
+        return this[prop];
+    }
+    set<K extends keyof this>(prop: K, value: this[K]) {
+        this[prop] = value;
+    }
+}
+
+class Person extends Base {
+    parts: number;
+    constructor(parts: number) {
+        super();
+        this.set("parts", parts);
+    }
+    getParts() {
+        return this.get("parts")
+    }
+}
+
+class OtherPerson {
+    parts: number;
+    constructor(parts: number) {
+        setProperty(this, "parts", parts);
+    }
+    getParts() {
+        return getProperty(this, "parts")
+    }
 }
 
 //// [keyofAndIndexedAccess.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
 var Shape = (function () {
     function Shape() {
     }
     return Shape;
 }());
+var TaggedShape = (function (_super) {
+    __extends(TaggedShape, _super);
+    function TaggedShape() {
+        return _super.apply(this, arguments) || this;
+    }
+    return TaggedShape;
+}(Shape));
 var Item = (function () {
     function Item() {
     }
@@ -249,6 +308,15 @@ function f32(key) {
     var shape = { name: "foo", width: 5, height: 10, visible: true };
     return shape[key]; // Shape[K]
 }
+function f33(shape, key) {
+    var name = getProperty(shape, "name");
+    var prop = getProperty(shape, key);
+    return prop;
+}
+function f34(ts) {
+    var tag1 = f33(ts, "tag");
+    var tag2 = getProperty(ts, "tag");
+}
 var C = (function () {
     function C() {
     }
@@ -261,6 +329,39 @@ function f40(c) {
     var y = c["y"];
     var z = c["z"];
 }
+// Repros from #12011
+var Base = (function () {
+    function Base() {
+    }
+    Base.prototype.get = function (prop) {
+        return this[prop];
+    };
+    Base.prototype.set = function (prop, value) {
+        this[prop] = value;
+    };
+    return Base;
+}());
+var Person = (function (_super) {
+    __extends(Person, _super);
+    function Person(parts) {
+        var _this = _super.call(this) || this;
+        _this.set("parts", parts);
+        return _this;
+    }
+    Person.prototype.getParts = function () {
+        return this.get("parts");
+    };
+    return Person;
+}(Base));
+var OtherPerson = (function () {
+    function OtherPerson(parts) {
+        setProperty(this, "parts", parts);
+    }
+    OtherPerson.prototype.getParts = function () {
+        return getProperty(this, "parts");
+    };
+    return OtherPerson;
+}());
 
 
 //// [keyofAndIndexedAccess.d.ts]
@@ -270,6 +371,9 @@ declare class Shape {
     height: number;
     visible: boolean;
 }
+declare class TaggedShape extends Shape {
+    tag: string;
+}
 declare class Item {
     name: string;
     price: number;
@@ -342,9 +446,25 @@ declare function pluck<T, K extends keyof T>(array: T[], key: K): T[K][];
 declare function f30(shapes: Shape[]): void;
 declare function f31<K extends keyof Shape>(key: K): Shape[K];
 declare function f32<K extends "width" | "height">(key: K): Shape[K];
+declare function f33<S extends Shape, K extends keyof S>(shape: S, key: K): S[K];
+declare function f34(ts: TaggedShape): void;
 declare class C {
     x: string;
     protected y: string;
     private z;
 }
 declare function f40(c: C): void;
+declare class Base {
+    get<K extends keyof this>(prop: K): this[K];
+    set<K extends keyof this>(prop: K, value: this[K]): void;
+}
+declare class Person extends Base {
+    parts: number;
+    constructor(parts: number);
+    getParts(): number;
+}
+declare class OtherPerson {
+    parts: number;
+    constructor(parts: number);
+    getParts(): number;
+}
diff --git a/tests/baselines/reference/keyofAndIndexedAccess.symbols b/tests/baselines/reference/keyofAndIndexedAccess.symbols
index d3e967ed12504..a76cf32b8d2fa 100644
--- a/tests/baselines/reference/keyofAndIndexedAccess.symbols
+++ b/tests/baselines/reference/keyofAndIndexedAccess.symbols
@@ -16,562 +16,694 @@ class Shape {
 >visible : Symbol(Shape.visible, Decl(keyofAndIndexedAccess.ts, 4, 19))
 }
 
+class TaggedShape extends Shape {
+>TaggedShape : Symbol(TaggedShape, Decl(keyofAndIndexedAccess.ts, 6, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    tag: string;
+>tag : Symbol(TaggedShape.tag, Decl(keyofAndIndexedAccess.ts, 8, 33))
+}
+
 class Item {
->Item : Symbol(Item, Decl(keyofAndIndexedAccess.ts, 6, 1))
+>Item : Symbol(Item, Decl(keyofAndIndexedAccess.ts, 10, 1))
 
     name: string;
->name : Symbol(Item.name, Decl(keyofAndIndexedAccess.ts, 8, 12))
+>name : Symbol(Item.name, Decl(keyofAndIndexedAccess.ts, 12, 12))
 
     price: number;
->price : Symbol(Item.price, Decl(keyofAndIndexedAccess.ts, 9, 17))
+>price : Symbol(Item.price, Decl(keyofAndIndexedAccess.ts, 13, 17))
 }
 
 class Options {
->Options : Symbol(Options, Decl(keyofAndIndexedAccess.ts, 11, 1))
+>Options : Symbol(Options, Decl(keyofAndIndexedAccess.ts, 15, 1))
 
     visible: "yes" | "no";
->visible : Symbol(Options.visible, Decl(keyofAndIndexedAccess.ts, 13, 15))
+>visible : Symbol(Options.visible, Decl(keyofAndIndexedAccess.ts, 17, 15))
 }
 
 type Dictionary<T> = { [x: string]: T };
->Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
->T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 17, 16))
->x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 17, 24))
->T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 17, 16))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 19, 1))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 21, 16))
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 21, 24))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 21, 16))
 
 const enum E { A, B, C }
->E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
->A : Symbol(E.A, Decl(keyofAndIndexedAccess.ts, 19, 14))
->B : Symbol(E.B, Decl(keyofAndIndexedAccess.ts, 19, 17))
->C : Symbol(E.C, Decl(keyofAndIndexedAccess.ts, 19, 20))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 21, 40))
+>A : Symbol(E.A, Decl(keyofAndIndexedAccess.ts, 23, 14))
+>B : Symbol(E.B, Decl(keyofAndIndexedAccess.ts, 23, 17))
+>C : Symbol(E.C, Decl(keyofAndIndexedAccess.ts, 23, 20))
 
 type K00 = keyof any;  // string | number
->K00 : Symbol(K00, Decl(keyofAndIndexedAccess.ts, 19, 24))
+>K00 : Symbol(K00, Decl(keyofAndIndexedAccess.ts, 23, 24))
 
 type K01 = keyof string;  // number | "toString" | "charAt" | ...
->K01 : Symbol(K01, Decl(keyofAndIndexedAccess.ts, 21, 21))
+>K01 : Symbol(K01, Decl(keyofAndIndexedAccess.ts, 25, 21))
 
 type K02 = keyof number;  // "toString" | "toFixed" | "toExponential" | ...
->K02 : Symbol(K02, Decl(keyofAndIndexedAccess.ts, 22, 24))
+>K02 : Symbol(K02, Decl(keyofAndIndexedAccess.ts, 26, 24))
 
 type K03 = keyof boolean;  // "valueOf"
->K03 : Symbol(K03, Decl(keyofAndIndexedAccess.ts, 23, 24))
+>K03 : Symbol(K03, Decl(keyofAndIndexedAccess.ts, 27, 24))
 
 type K04 = keyof void;  // never
->K04 : Symbol(K04, Decl(keyofAndIndexedAccess.ts, 24, 25))
+>K04 : Symbol(K04, Decl(keyofAndIndexedAccess.ts, 28, 25))
 
 type K05 = keyof undefined;  // never
->K05 : Symbol(K05, Decl(keyofAndIndexedAccess.ts, 25, 22))
+>K05 : Symbol(K05, Decl(keyofAndIndexedAccess.ts, 29, 22))
 
 type K06 = keyof null;  // never
->K06 : Symbol(K06, Decl(keyofAndIndexedAccess.ts, 26, 27))
+>K06 : Symbol(K06, Decl(keyofAndIndexedAccess.ts, 30, 27))
 
 type K07 = keyof never;  // never
->K07 : Symbol(K07, Decl(keyofAndIndexedAccess.ts, 27, 22))
+>K07 : Symbol(K07, Decl(keyofAndIndexedAccess.ts, 31, 22))
 
 type K10 = keyof Shape;  // "name" | "width" | "height" | "visible"
->K10 : Symbol(K10, Decl(keyofAndIndexedAccess.ts, 28, 23))
+>K10 : Symbol(K10, Decl(keyofAndIndexedAccess.ts, 32, 23))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
 type K11 = keyof Shape[];  // number | "length" | "toString" | ...
->K11 : Symbol(K11, Decl(keyofAndIndexedAccess.ts, 30, 23))
+>K11 : Symbol(K11, Decl(keyofAndIndexedAccess.ts, 34, 23))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
 type K12 = keyof Dictionary<Shape>;  // string | number
->K12 : Symbol(K12, Decl(keyofAndIndexedAccess.ts, 31, 25))
->Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>K12 : Symbol(K12, Decl(keyofAndIndexedAccess.ts, 35, 25))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 19, 1))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
 type K13 = keyof {};  // never
->K13 : Symbol(K13, Decl(keyofAndIndexedAccess.ts, 32, 35))
+>K13 : Symbol(K13, Decl(keyofAndIndexedAccess.ts, 36, 35))
 
 type K14 = keyof Object;  // "constructor" | "toString" | ...
->K14 : Symbol(K14, Decl(keyofAndIndexedAccess.ts, 33, 20))
+>K14 : Symbol(K14, Decl(keyofAndIndexedAccess.ts, 37, 20))
 >Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
 
 type K15 = keyof E;  // "toString" | "toFixed" | "toExponential" | ...
->K15 : Symbol(K15, Decl(keyofAndIndexedAccess.ts, 34, 24))
->E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+>K15 : Symbol(K15, Decl(keyofAndIndexedAccess.ts, 38, 24))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 21, 40))
 
 type K16 = keyof [string, number];  // number | "0" | "1" | "length" | "toString" | ...
->K16 : Symbol(K16, Decl(keyofAndIndexedAccess.ts, 35, 19))
+>K16 : Symbol(K16, Decl(keyofAndIndexedAccess.ts, 39, 19))
 
 type K17 = keyof (Shape | Item);  // "name"
->K17 : Symbol(K17, Decl(keyofAndIndexedAccess.ts, 36, 34))
+>K17 : Symbol(K17, Decl(keyofAndIndexedAccess.ts, 40, 34))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
->Item : Symbol(Item, Decl(keyofAndIndexedAccess.ts, 6, 1))
+>Item : Symbol(Item, Decl(keyofAndIndexedAccess.ts, 10, 1))
 
 type K18 = keyof (Shape & Item);  // "name" | "width" | "height" | "visible" | "price"
->K18 : Symbol(K18, Decl(keyofAndIndexedAccess.ts, 37, 32))
+>K18 : Symbol(K18, Decl(keyofAndIndexedAccess.ts, 41, 32))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
->Item : Symbol(Item, Decl(keyofAndIndexedAccess.ts, 6, 1))
+>Item : Symbol(Item, Decl(keyofAndIndexedAccess.ts, 10, 1))
 
 type KeyOf<T> = keyof T;
->KeyOf : Symbol(KeyOf, Decl(keyofAndIndexedAccess.ts, 38, 32))
->T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 40, 11))
->T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 40, 11))
+>KeyOf : Symbol(KeyOf, Decl(keyofAndIndexedAccess.ts, 42, 32))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 44, 11))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 44, 11))
 
 type K20 = KeyOf<Shape>;  // "name" | "width" | "height" | "visible"
->K20 : Symbol(K20, Decl(keyofAndIndexedAccess.ts, 40, 24))
->KeyOf : Symbol(KeyOf, Decl(keyofAndIndexedAccess.ts, 38, 32))
+>K20 : Symbol(K20, Decl(keyofAndIndexedAccess.ts, 44, 24))
+>KeyOf : Symbol(KeyOf, Decl(keyofAndIndexedAccess.ts, 42, 32))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
 type K21 = KeyOf<Dictionary<Shape>>;  // string | number
->K21 : Symbol(K21, Decl(keyofAndIndexedAccess.ts, 42, 24))
->KeyOf : Symbol(KeyOf, Decl(keyofAndIndexedAccess.ts, 38, 32))
->Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>K21 : Symbol(K21, Decl(keyofAndIndexedAccess.ts, 46, 24))
+>KeyOf : Symbol(KeyOf, Decl(keyofAndIndexedAccess.ts, 42, 32))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 19, 1))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
 type NAME = "name";
->NAME : Symbol(NAME, Decl(keyofAndIndexedAccess.ts, 43, 36))
+>NAME : Symbol(NAME, Decl(keyofAndIndexedAccess.ts, 47, 36))
 
 type WIDTH_OR_HEIGHT = "width" | "height";
->WIDTH_OR_HEIGHT : Symbol(WIDTH_OR_HEIGHT, Decl(keyofAndIndexedAccess.ts, 45, 19))
+>WIDTH_OR_HEIGHT : Symbol(WIDTH_OR_HEIGHT, Decl(keyofAndIndexedAccess.ts, 49, 19))
 
 type Q10 = Shape["name"];  // string
->Q10 : Symbol(Q10, Decl(keyofAndIndexedAccess.ts, 46, 42))
+>Q10 : Symbol(Q10, Decl(keyofAndIndexedAccess.ts, 50, 42))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
 type Q11 = Shape["width" | "height"];  // number
->Q11 : Symbol(Q11, Decl(keyofAndIndexedAccess.ts, 48, 25))
+>Q11 : Symbol(Q11, Decl(keyofAndIndexedAccess.ts, 52, 25))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
 type Q12 = Shape["name" | "visible"];  // string | boolean
->Q12 : Symbol(Q12, Decl(keyofAndIndexedAccess.ts, 49, 37))
+>Q12 : Symbol(Q12, Decl(keyofAndIndexedAccess.ts, 53, 37))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
 type Q20 = Shape[NAME];  // string
->Q20 : Symbol(Q20, Decl(keyofAndIndexedAccess.ts, 50, 37))
+>Q20 : Symbol(Q20, Decl(keyofAndIndexedAccess.ts, 54, 37))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
->NAME : Symbol(NAME, Decl(keyofAndIndexedAccess.ts, 43, 36))
+>NAME : Symbol(NAME, Decl(keyofAndIndexedAccess.ts, 47, 36))
 
 type Q21 = Shape[WIDTH_OR_HEIGHT];  // number
->Q21 : Symbol(Q21, Decl(keyofAndIndexedAccess.ts, 52, 23))
+>Q21 : Symbol(Q21, Decl(keyofAndIndexedAccess.ts, 56, 23))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
->WIDTH_OR_HEIGHT : Symbol(WIDTH_OR_HEIGHT, Decl(keyofAndIndexedAccess.ts, 45, 19))
+>WIDTH_OR_HEIGHT : Symbol(WIDTH_OR_HEIGHT, Decl(keyofAndIndexedAccess.ts, 49, 19))
 
 type Q30 = [string, number][0];  // string
->Q30 : Symbol(Q30, Decl(keyofAndIndexedAccess.ts, 53, 34))
+>Q30 : Symbol(Q30, Decl(keyofAndIndexedAccess.ts, 57, 34))
 
 type Q31 = [string, number][1];  // number
->Q31 : Symbol(Q31, Decl(keyofAndIndexedAccess.ts, 55, 31))
+>Q31 : Symbol(Q31, Decl(keyofAndIndexedAccess.ts, 59, 31))
 
 type Q32 = [string, number][2];  // string | number
->Q32 : Symbol(Q32, Decl(keyofAndIndexedAccess.ts, 56, 31))
+>Q32 : Symbol(Q32, Decl(keyofAndIndexedAccess.ts, 60, 31))
 
 type Q33 = [string, number][E.A];  // string
->Q33 : Symbol(Q33, Decl(keyofAndIndexedAccess.ts, 57, 31))
->E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
->A : Symbol(E.A, Decl(keyofAndIndexedAccess.ts, 19, 14))
+>Q33 : Symbol(Q33, Decl(keyofAndIndexedAccess.ts, 61, 31))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 21, 40))
+>A : Symbol(E.A, Decl(keyofAndIndexedAccess.ts, 23, 14))
 
 type Q34 = [string, number][E.B];  // number
->Q34 : Symbol(Q34, Decl(keyofAndIndexedAccess.ts, 58, 33))
->E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
->B : Symbol(E.B, Decl(keyofAndIndexedAccess.ts, 19, 17))
+>Q34 : Symbol(Q34, Decl(keyofAndIndexedAccess.ts, 62, 33))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 21, 40))
+>B : Symbol(E.B, Decl(keyofAndIndexedAccess.ts, 23, 17))
 
 type Q35 = [string, number][E.C];  // string | number
->Q35 : Symbol(Q35, Decl(keyofAndIndexedAccess.ts, 59, 33))
->E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
->C : Symbol(E.C, Decl(keyofAndIndexedAccess.ts, 19, 20))
+>Q35 : Symbol(Q35, Decl(keyofAndIndexedAccess.ts, 63, 33))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 21, 40))
+>C : Symbol(E.C, Decl(keyofAndIndexedAccess.ts, 23, 20))
 
 type Q36 = [string, number]["0"];  // string
->Q36 : Symbol(Q36, Decl(keyofAndIndexedAccess.ts, 60, 33))
+>Q36 : Symbol(Q36, Decl(keyofAndIndexedAccess.ts, 64, 33))
 
 type Q37 = [string, number]["1"];  // string
->Q37 : Symbol(Q37, Decl(keyofAndIndexedAccess.ts, 61, 33))
+>Q37 : Symbol(Q37, Decl(keyofAndIndexedAccess.ts, 65, 33))
 
 type Q40 = (Shape | Options)["visible"];  // boolean | "yes" | "no"
->Q40 : Symbol(Q40, Decl(keyofAndIndexedAccess.ts, 62, 33))
+>Q40 : Symbol(Q40, Decl(keyofAndIndexedAccess.ts, 66, 33))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
->Options : Symbol(Options, Decl(keyofAndIndexedAccess.ts, 11, 1))
+>Options : Symbol(Options, Decl(keyofAndIndexedAccess.ts, 15, 1))
 
 type Q41 = (Shape & Options)["visible"];  // true & "yes" | true & "no" | false & "yes" | false & "no"
->Q41 : Symbol(Q41, Decl(keyofAndIndexedAccess.ts, 64, 40))
+>Q41 : Symbol(Q41, Decl(keyofAndIndexedAccess.ts, 68, 40))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
->Options : Symbol(Options, Decl(keyofAndIndexedAccess.ts, 11, 1))
+>Options : Symbol(Options, Decl(keyofAndIndexedAccess.ts, 15, 1))
 
 type Q50 = Dictionary<Shape>["howdy"];  // Shape
->Q50 : Symbol(Q50, Decl(keyofAndIndexedAccess.ts, 65, 40))
->Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Q50 : Symbol(Q50, Decl(keyofAndIndexedAccess.ts, 69, 40))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 19, 1))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
 type Q51 = Dictionary<Shape>[123];  // Shape
->Q51 : Symbol(Q51, Decl(keyofAndIndexedAccess.ts, 67, 38))
->Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Q51 : Symbol(Q51, Decl(keyofAndIndexedAccess.ts, 71, 38))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 19, 1))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
 type Q52 = Dictionary<Shape>[E.B];  // Shape
->Q52 : Symbol(Q52, Decl(keyofAndIndexedAccess.ts, 68, 34))
->Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Q52 : Symbol(Q52, Decl(keyofAndIndexedAccess.ts, 72, 34))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 19, 1))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
->E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
->B : Symbol(E.B, Decl(keyofAndIndexedAccess.ts, 19, 17))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 21, 40))
+>B : Symbol(E.B, Decl(keyofAndIndexedAccess.ts, 23, 17))
 
 declare let cond: boolean;
->cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 75, 11))
 
 function getProperty<T, K extends keyof T>(obj: T, key: K) {
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 73, 21))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 73, 23))
->T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 73, 21))
->obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 73, 43))
->T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 73, 21))
->key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 73, 50))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 73, 23))
-
-    return obj[key];
->obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 73, 43))
->key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 73, 50))
-}
-
-function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
->setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
 >T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 77, 21))
 >K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 77, 23))
 >T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 77, 21))
 >obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 77, 43))
 >T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 77, 21))
 >key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 77, 50))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 77, 23))
->value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 77, 58))
->T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 77, 21))
 >K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 77, 23))
 
-    obj[key] = value;
+    return obj[key];
 >obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 77, 43))
 >key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 77, 50))
->value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 77, 58))
+}
+
+function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 79, 1))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 81, 21))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 81, 23))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 81, 21))
+>obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 81, 43))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 81, 21))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 81, 50))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 81, 23))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 81, 58))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 81, 21))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 81, 23))
+
+    obj[key] = value;
+>obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 81, 43))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 81, 50))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 81, 58))
 }
 
 function f10(shape: Shape) {
->f10 : Symbol(f10, Decl(keyofAndIndexedAccess.ts, 79, 1))
->shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>f10 : Symbol(f10, Decl(keyofAndIndexedAccess.ts, 83, 1))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 85, 13))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
     let name = getProperty(shape, "name");  // string
->name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 82, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 86, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 85, 13))
 
     let widthOrHeight = getProperty(shape, cond ? "width" : "height");  // number
->widthOrHeight : Symbol(widthOrHeight, Decl(keyofAndIndexedAccess.ts, 83, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
->cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+>widthOrHeight : Symbol(widthOrHeight, Decl(keyofAndIndexedAccess.ts, 87, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 85, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 75, 11))
 
     let nameOrVisible = getProperty(shape, cond ? "name" : "visible");  // string | boolean
->nameOrVisible : Symbol(nameOrVisible, Decl(keyofAndIndexedAccess.ts, 84, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
->cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+>nameOrVisible : Symbol(nameOrVisible, Decl(keyofAndIndexedAccess.ts, 88, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 85, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 75, 11))
 
     setProperty(shape, "name", "rectangle");
->setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
->shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 79, 1))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 85, 13))
 
     setProperty(shape, cond ? "width" : "height", 10);
->setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
->shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
->cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 79, 1))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 85, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 75, 11))
 
     setProperty(shape, cond ? "name" : "visible", true);  // Technically not safe
->setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
->shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
->cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 79, 1))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 85, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 75, 11))
 }
 
 function f11(a: Shape[]) {
->f11 : Symbol(f11, Decl(keyofAndIndexedAccess.ts, 88, 1))
->a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+>f11 : Symbol(f11, Decl(keyofAndIndexedAccess.ts, 92, 1))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 94, 13))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
     let len = getProperty(a, "length");  // number
->len : Symbol(len, Decl(keyofAndIndexedAccess.ts, 91, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+>len : Symbol(len, Decl(keyofAndIndexedAccess.ts, 95, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 94, 13))
 
     let shape = getProperty(a, 1000);    // Shape
->shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 92, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 96, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 94, 13))
 
     setProperty(a, 1000, getProperty(a, 1001));
->setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
->a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 79, 1))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 94, 13))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 94, 13))
 }
 
 function f12(t: [Shape, boolean]) {
->f12 : Symbol(f12, Decl(keyofAndIndexedAccess.ts, 94, 1))
->t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+>f12 : Symbol(f12, Decl(keyofAndIndexedAccess.ts, 98, 1))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 100, 13))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
     let len = getProperty(t, "length");
->len : Symbol(len, Decl(keyofAndIndexedAccess.ts, 97, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+>len : Symbol(len, Decl(keyofAndIndexedAccess.ts, 101, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 100, 13))
 
     let s1 = getProperty(t, 0);    // Shape
->s1 : Symbol(s1, Decl(keyofAndIndexedAccess.ts, 98, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+>s1 : Symbol(s1, Decl(keyofAndIndexedAccess.ts, 102, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 100, 13))
 
     let s2 = getProperty(t, "0");  // Shape
->s2 : Symbol(s2, Decl(keyofAndIndexedAccess.ts, 99, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+>s2 : Symbol(s2, Decl(keyofAndIndexedAccess.ts, 103, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 100, 13))
 
     let b1 = getProperty(t, 1);    // boolean
->b1 : Symbol(b1, Decl(keyofAndIndexedAccess.ts, 100, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+>b1 : Symbol(b1, Decl(keyofAndIndexedAccess.ts, 104, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 100, 13))
 
     let b2 = getProperty(t, "1");  // boolean
->b2 : Symbol(b2, Decl(keyofAndIndexedAccess.ts, 101, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+>b2 : Symbol(b2, Decl(keyofAndIndexedAccess.ts, 105, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 100, 13))
 
     let x1 = getProperty(t, 2);    // Shape | boolean
->x1 : Symbol(x1, Decl(keyofAndIndexedAccess.ts, 102, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+>x1 : Symbol(x1, Decl(keyofAndIndexedAccess.ts, 106, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 100, 13))
 }
 
 function f13(foo: any, bar: any) {
->f13 : Symbol(f13, Decl(keyofAndIndexedAccess.ts, 103, 1))
->foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 105, 13))
->bar : Symbol(bar, Decl(keyofAndIndexedAccess.ts, 105, 22))
+>f13 : Symbol(f13, Decl(keyofAndIndexedAccess.ts, 107, 1))
+>foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 109, 13))
+>bar : Symbol(bar, Decl(keyofAndIndexedAccess.ts, 109, 22))
 
     let x = getProperty(foo, "x");  // any
->x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 106, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 105, 13))
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 110, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 109, 13))
 
     let y = getProperty(foo, 100);  // any
->y : Symbol(y, Decl(keyofAndIndexedAccess.ts, 107, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 105, 13))
+>y : Symbol(y, Decl(keyofAndIndexedAccess.ts, 111, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 109, 13))
 
     let z = getProperty(foo, bar);  // any
->z : Symbol(z, Decl(keyofAndIndexedAccess.ts, 108, 7))
->getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
->foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 105, 13))
->bar : Symbol(bar, Decl(keyofAndIndexedAccess.ts, 105, 22))
+>z : Symbol(z, Decl(keyofAndIndexedAccess.ts, 112, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 109, 13))
+>bar : Symbol(bar, Decl(keyofAndIndexedAccess.ts, 109, 22))
 }
 
 class Component<PropType> {
->Component : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 109, 1))
->PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
+>Component : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 113, 1))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 115, 16))
 
     props: PropType;
->props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
->PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
+>props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 115, 27))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 115, 16))
 
     getProperty<K extends keyof PropType>(key: K) {
->getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 113, 16))
->PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
->key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 113, 42))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 113, 16))
+>getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 116, 20))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 117, 16))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 115, 16))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 117, 42))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 117, 16))
 
         return this.props[key];
->this.props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
->this : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 109, 1))
->props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
->key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 113, 42))
+>this.props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 115, 27))
+>this : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 113, 1))
+>props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 115, 27))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 117, 42))
     }
     setProperty<K extends keyof PropType>(key: K, value: PropType[K]) {
->setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 116, 16))
->PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
->key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 116, 42))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 116, 16))
->value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 116, 49))
->PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 116, 16))
+>setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 119, 5))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 120, 16))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 115, 16))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 120, 42))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 120, 16))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 120, 49))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 115, 16))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 120, 16))
 
         this.props[key] = value;
->this.props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
->this : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 109, 1))
->props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
->key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 116, 42))
->value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 116, 49))
+>this.props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 115, 27))
+>this : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 113, 1))
+>props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 115, 27))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 120, 42))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 120, 49))
     }
 }
 
 function f20(component: Component<Shape>) {
->f20 : Symbol(f20, Decl(keyofAndIndexedAccess.ts, 119, 1))
->component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
->Component : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 109, 1))
+>f20 : Symbol(f20, Decl(keyofAndIndexedAccess.ts, 123, 1))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 125, 13))
+>Component : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 113, 1))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
     let name = component.getProperty("name");  // string
->name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 122, 7))
->component.getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
->component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
->getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 126, 7))
+>component.getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 116, 20))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 125, 13))
+>getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 116, 20))
 
     let widthOrHeight = component.getProperty(cond ? "width" : "height");  // number
->widthOrHeight : Symbol(widthOrHeight, Decl(keyofAndIndexedAccess.ts, 123, 7))
->component.getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
->component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
->getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
->cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+>widthOrHeight : Symbol(widthOrHeight, Decl(keyofAndIndexedAccess.ts, 127, 7))
+>component.getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 116, 20))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 125, 13))
+>getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 116, 20))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 75, 11))
 
     let nameOrVisible = component.getProperty(cond ? "name" : "visible");  // string | boolean
->nameOrVisible : Symbol(nameOrVisible, Decl(keyofAndIndexedAccess.ts, 124, 7))
->component.getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
->component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
->getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
->cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+>nameOrVisible : Symbol(nameOrVisible, Decl(keyofAndIndexedAccess.ts, 128, 7))
+>component.getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 116, 20))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 125, 13))
+>getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 116, 20))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 75, 11))
 
     component.setProperty("name", "rectangle");
->component.setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
->component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
->setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>component.setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 119, 5))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 125, 13))
+>setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 119, 5))
 
     component.setProperty(cond ? "width" : "height", 10)
->component.setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
->component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
->setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
->cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+>component.setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 119, 5))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 125, 13))
+>setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 119, 5))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 75, 11))
 
     component.setProperty(cond ? "name" : "visible", true);  // Technically not safe
->component.setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
->component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
->setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
->cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+>component.setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 119, 5))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 125, 13))
+>setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 119, 5))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 75, 11))
 }
 
 function pluck<T, K extends keyof T>(array: T[], key: K) {
->pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 128, 1))
->T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 130, 15))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 130, 17))
->T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 130, 15))
->array : Symbol(array, Decl(keyofAndIndexedAccess.ts, 130, 37))
->T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 130, 15))
->key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 130, 48))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 130, 17))
+>pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 132, 1))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 134, 15))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 134, 17))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 134, 15))
+>array : Symbol(array, Decl(keyofAndIndexedAccess.ts, 134, 37))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 134, 15))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 134, 48))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 134, 17))
 
     return array.map(x => x[key]);
 >array.map : Symbol(Array.map, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
->array : Symbol(array, Decl(keyofAndIndexedAccess.ts, 130, 37))
+>array : Symbol(array, Decl(keyofAndIndexedAccess.ts, 134, 37))
 >map : Symbol(Array.map, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
->x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 131, 21))
->x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 131, 21))
->key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 130, 48))
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 135, 21))
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 135, 21))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 134, 48))
 }
 
 function f30(shapes: Shape[]) {
->f30 : Symbol(f30, Decl(keyofAndIndexedAccess.ts, 132, 1))
->shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 134, 13))
+>f30 : Symbol(f30, Decl(keyofAndIndexedAccess.ts, 136, 1))
+>shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 138, 13))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
 
     let names = pluck(shapes, "name");    // string[]
->names : Symbol(names, Decl(keyofAndIndexedAccess.ts, 135, 7))
->pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 128, 1))
->shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 134, 13))
+>names : Symbol(names, Decl(keyofAndIndexedAccess.ts, 139, 7))
+>pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 132, 1))
+>shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 138, 13))
 
     let widths = pluck(shapes, "width");  // number[]
->widths : Symbol(widths, Decl(keyofAndIndexedAccess.ts, 136, 7))
->pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 128, 1))
->shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 134, 13))
+>widths : Symbol(widths, Decl(keyofAndIndexedAccess.ts, 140, 7))
+>pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 132, 1))
+>shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 138, 13))
 
     let nameOrVisibles = pluck(shapes, cond ? "name" : "visible");  // (string | boolean)[]
->nameOrVisibles : Symbol(nameOrVisibles, Decl(keyofAndIndexedAccess.ts, 137, 7))
->pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 128, 1))
->shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 134, 13))
->cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+>nameOrVisibles : Symbol(nameOrVisibles, Decl(keyofAndIndexedAccess.ts, 141, 7))
+>pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 132, 1))
+>shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 138, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 75, 11))
 }
 
 function f31<K extends keyof Shape>(key: K) {
->f31 : Symbol(f31, Decl(keyofAndIndexedAccess.ts, 138, 1))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 140, 13))
+>f31 : Symbol(f31, Decl(keyofAndIndexedAccess.ts, 142, 1))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 144, 13))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
->key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 140, 36))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 140, 13))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 144, 36))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 144, 13))
 
     const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
->shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 141, 9))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 145, 9))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
->name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 141, 26))
->width : Symbol(width, Decl(keyofAndIndexedAccess.ts, 141, 39))
->height : Symbol(height, Decl(keyofAndIndexedAccess.ts, 141, 49))
->visible : Symbol(visible, Decl(keyofAndIndexedAccess.ts, 141, 61))
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 145, 26))
+>width : Symbol(width, Decl(keyofAndIndexedAccess.ts, 145, 39))
+>height : Symbol(height, Decl(keyofAndIndexedAccess.ts, 145, 49))
+>visible : Symbol(visible, Decl(keyofAndIndexedAccess.ts, 145, 61))
 
     return shape[key];  // Shape[K]
->shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 141, 9))
->key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 140, 36))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 145, 9))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 144, 36))
 }
 
 function f32<K extends "width" | "height">(key: K) {
->f32 : Symbol(f32, Decl(keyofAndIndexedAccess.ts, 143, 1))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 145, 13))
->key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 145, 43))
->K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 145, 13))
+>f32 : Symbol(f32, Decl(keyofAndIndexedAccess.ts, 147, 1))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 149, 13))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 149, 43))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 149, 13))
 
     const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
->shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 146, 9))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 150, 9))
 >Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
->name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 146, 26))
->width : Symbol(width, Decl(keyofAndIndexedAccess.ts, 146, 39))
->height : Symbol(height, Decl(keyofAndIndexedAccess.ts, 146, 49))
->visible : Symbol(visible, Decl(keyofAndIndexedAccess.ts, 146, 61))
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 150, 26))
+>width : Symbol(width, Decl(keyofAndIndexedAccess.ts, 150, 39))
+>height : Symbol(height, Decl(keyofAndIndexedAccess.ts, 150, 49))
+>visible : Symbol(visible, Decl(keyofAndIndexedAccess.ts, 150, 61))
 
     return shape[key];  // Shape[K]
->shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 146, 9))
->key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 145, 43))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 150, 9))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 149, 43))
+}
+
+function f33<S extends Shape, K extends keyof S>(shape: S, key: K) {
+>f33 : Symbol(f33, Decl(keyofAndIndexedAccess.ts, 152, 1))
+>S : Symbol(S, Decl(keyofAndIndexedAccess.ts, 154, 13))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 154, 29))
+>S : Symbol(S, Decl(keyofAndIndexedAccess.ts, 154, 13))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 154, 49))
+>S : Symbol(S, Decl(keyofAndIndexedAccess.ts, 154, 13))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 154, 58))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 154, 29))
+
+    let name = getProperty(shape, "name");
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 155, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 154, 49))
+
+    let prop = getProperty(shape, key);
+>prop : Symbol(prop, Decl(keyofAndIndexedAccess.ts, 156, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 154, 49))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 154, 58))
+
+    return prop;
+>prop : Symbol(prop, Decl(keyofAndIndexedAccess.ts, 156, 7))
+}
+
+function f34(ts: TaggedShape) {
+>f34 : Symbol(f34, Decl(keyofAndIndexedAccess.ts, 158, 1))
+>ts : Symbol(ts, Decl(keyofAndIndexedAccess.ts, 160, 13))
+>TaggedShape : Symbol(TaggedShape, Decl(keyofAndIndexedAccess.ts, 6, 1))
+
+    let tag1 = f33(ts, "tag");
+>tag1 : Symbol(tag1, Decl(keyofAndIndexedAccess.ts, 161, 7))
+>f33 : Symbol(f33, Decl(keyofAndIndexedAccess.ts, 152, 1))
+>ts : Symbol(ts, Decl(keyofAndIndexedAccess.ts, 160, 13))
+
+    let tag2 = getProperty(ts, "tag");
+>tag2 : Symbol(tag2, Decl(keyofAndIndexedAccess.ts, 162, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>ts : Symbol(ts, Decl(keyofAndIndexedAccess.ts, 160, 13))
 }
 
 class C {
->C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 163, 1))
 
     public x: string;
->x : Symbol(C.x, Decl(keyofAndIndexedAccess.ts, 150, 9))
+>x : Symbol(C.x, Decl(keyofAndIndexedAccess.ts, 165, 9))
 
     protected y: string;
->y : Symbol(C.y, Decl(keyofAndIndexedAccess.ts, 151, 21))
+>y : Symbol(C.y, Decl(keyofAndIndexedAccess.ts, 166, 21))
 
     private z: string;
->z : Symbol(C.z, Decl(keyofAndIndexedAccess.ts, 152, 24))
+>z : Symbol(C.z, Decl(keyofAndIndexedAccess.ts, 167, 24))
 }
 
 // Indexed access expressions have always permitted access to private and protected members.
 // For consistency we also permit such access in indexed access types.
 function f40(c: C) {
->f40 : Symbol(f40, Decl(keyofAndIndexedAccess.ts, 154, 1))
->c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 158, 13))
->C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+>f40 : Symbol(f40, Decl(keyofAndIndexedAccess.ts, 169, 1))
+>c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 173, 13))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 163, 1))
 
     type X = C["x"];
->X : Symbol(X, Decl(keyofAndIndexedAccess.ts, 158, 20))
->C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+>X : Symbol(X, Decl(keyofAndIndexedAccess.ts, 173, 20))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 163, 1))
 
     type Y = C["y"];
->Y : Symbol(Y, Decl(keyofAndIndexedAccess.ts, 159, 20))
->C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+>Y : Symbol(Y, Decl(keyofAndIndexedAccess.ts, 174, 20))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 163, 1))
 
     type Z = C["z"];
->Z : Symbol(Z, Decl(keyofAndIndexedAccess.ts, 160, 20))
->C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+>Z : Symbol(Z, Decl(keyofAndIndexedAccess.ts, 175, 20))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 163, 1))
 
     let x: X = c["x"];
->x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 162, 7))
->X : Symbol(X, Decl(keyofAndIndexedAccess.ts, 158, 20))
->c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 158, 13))
->"x" : Symbol(C.x, Decl(keyofAndIndexedAccess.ts, 150, 9))
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 177, 7))
+>X : Symbol(X, Decl(keyofAndIndexedAccess.ts, 173, 20))
+>c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 173, 13))
+>"x" : Symbol(C.x, Decl(keyofAndIndexedAccess.ts, 165, 9))
 
     let y: Y = c["y"];
->y : Symbol(y, Decl(keyofAndIndexedAccess.ts, 163, 7))
->Y : Symbol(Y, Decl(keyofAndIndexedAccess.ts, 159, 20))
->c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 158, 13))
->"y" : Symbol(C.y, Decl(keyofAndIndexedAccess.ts, 151, 21))
+>y : Symbol(y, Decl(keyofAndIndexedAccess.ts, 178, 7))
+>Y : Symbol(Y, Decl(keyofAndIndexedAccess.ts, 174, 20))
+>c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 173, 13))
+>"y" : Symbol(C.y, Decl(keyofAndIndexedAccess.ts, 166, 21))
 
     let z: Z = c["z"];
->z : Symbol(z, Decl(keyofAndIndexedAccess.ts, 164, 7))
->Z : Symbol(Z, Decl(keyofAndIndexedAccess.ts, 160, 20))
->c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 158, 13))
->"z" : Symbol(C.z, Decl(keyofAndIndexedAccess.ts, 152, 24))
+>z : Symbol(z, Decl(keyofAndIndexedAccess.ts, 179, 7))
+>Z : Symbol(Z, Decl(keyofAndIndexedAccess.ts, 175, 20))
+>c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 173, 13))
+>"z" : Symbol(C.z, Decl(keyofAndIndexedAccess.ts, 167, 24))
+}
+
+// Repros from #12011
+
+class Base {
+>Base : Symbol(Base, Decl(keyofAndIndexedAccess.ts, 180, 1))
+
+    get<K extends keyof this>(prop: K) {
+>get : Symbol(Base.get, Decl(keyofAndIndexedAccess.ts, 184, 12))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 185, 8))
+>prop : Symbol(prop, Decl(keyofAndIndexedAccess.ts, 185, 30))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 185, 8))
+
+        return this[prop];
+>this : Symbol(Base, Decl(keyofAndIndexedAccess.ts, 180, 1))
+>prop : Symbol(prop, Decl(keyofAndIndexedAccess.ts, 185, 30))
+    }
+    set<K extends keyof this>(prop: K, value: this[K]) {
+>set : Symbol(Base.set, Decl(keyofAndIndexedAccess.ts, 187, 5))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 188, 8))
+>prop : Symbol(prop, Decl(keyofAndIndexedAccess.ts, 188, 30))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 188, 8))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 188, 38))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 188, 8))
+
+        this[prop] = value;
+>this : Symbol(Base, Decl(keyofAndIndexedAccess.ts, 180, 1))
+>prop : Symbol(prop, Decl(keyofAndIndexedAccess.ts, 188, 30))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 188, 38))
+    }
+}
+
+class Person extends Base {
+>Person : Symbol(Person, Decl(keyofAndIndexedAccess.ts, 191, 1))
+>Base : Symbol(Base, Decl(keyofAndIndexedAccess.ts, 180, 1))
+
+    parts: number;
+>parts : Symbol(Person.parts, Decl(keyofAndIndexedAccess.ts, 193, 27))
+
+    constructor(parts: number) {
+>parts : Symbol(parts, Decl(keyofAndIndexedAccess.ts, 195, 16))
+
+        super();
+>super : Symbol(Base, Decl(keyofAndIndexedAccess.ts, 180, 1))
+
+        this.set("parts", parts);
+>this.set : Symbol(Base.set, Decl(keyofAndIndexedAccess.ts, 187, 5))
+>this : Symbol(Person, Decl(keyofAndIndexedAccess.ts, 191, 1))
+>set : Symbol(Base.set, Decl(keyofAndIndexedAccess.ts, 187, 5))
+>parts : Symbol(parts, Decl(keyofAndIndexedAccess.ts, 195, 16))
+    }
+    getParts() {
+>getParts : Symbol(Person.getParts, Decl(keyofAndIndexedAccess.ts, 198, 5))
+
+        return this.get("parts")
+>this.get : Symbol(Base.get, Decl(keyofAndIndexedAccess.ts, 184, 12))
+>this : Symbol(Person, Decl(keyofAndIndexedAccess.ts, 191, 1))
+>get : Symbol(Base.get, Decl(keyofAndIndexedAccess.ts, 184, 12))
+    }
+}
+
+class OtherPerson {
+>OtherPerson : Symbol(OtherPerson, Decl(keyofAndIndexedAccess.ts, 202, 1))
+
+    parts: number;
+>parts : Symbol(OtherPerson.parts, Decl(keyofAndIndexedAccess.ts, 204, 19))
+
+    constructor(parts: number) {
+>parts : Symbol(parts, Decl(keyofAndIndexedAccess.ts, 206, 16))
+
+        setProperty(this, "parts", parts);
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 79, 1))
+>this : Symbol(OtherPerson, Decl(keyofAndIndexedAccess.ts, 202, 1))
+>parts : Symbol(parts, Decl(keyofAndIndexedAccess.ts, 206, 16))
+    }
+    getParts() {
+>getParts : Symbol(OtherPerson.getParts, Decl(keyofAndIndexedAccess.ts, 208, 5))
+
+        return getProperty(this, "parts")
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 75, 26))
+>this : Symbol(OtherPerson, Decl(keyofAndIndexedAccess.ts, 202, 1))
+    }
 }
diff --git a/tests/baselines/reference/keyofAndIndexedAccess.types b/tests/baselines/reference/keyofAndIndexedAccess.types
index 74c06a2535da7..a5395db8292ae 100644
--- a/tests/baselines/reference/keyofAndIndexedAccess.types
+++ b/tests/baselines/reference/keyofAndIndexedAccess.types
@@ -16,6 +16,14 @@ class Shape {
 >visible : boolean
 }
 
+class TaggedShape extends Shape {
+>TaggedShape : TaggedShape
+>Shape : Shape
+
+    tag: string;
+>tag : string
+}
+
 class Item {
 >Item : Item
 
@@ -626,6 +634,55 @@ function f32<K extends "width" | "height">(key: K) {
 >key : K
 }
 
+function f33<S extends Shape, K extends keyof S>(shape: S, key: K) {
+>f33 : <S extends Shape, K extends keyof S>(shape: S, key: K) => S[K]
+>S : S
+>Shape : Shape
+>K : K
+>S : S
+>shape : S
+>S : S
+>key : K
+>K : K
+
+    let name = getProperty(shape, "name");
+>name : string
+>getProperty(shape, "name") : string
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>shape : S
+>"name" : "name"
+
+    let prop = getProperty(shape, key);
+>prop : S[K]
+>getProperty(shape, key) : S[K]
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>shape : S
+>key : K
+
+    return prop;
+>prop : S[K]
+}
+
+function f34(ts: TaggedShape) {
+>f34 : (ts: TaggedShape) => void
+>ts : TaggedShape
+>TaggedShape : TaggedShape
+
+    let tag1 = f33(ts, "tag");
+>tag1 : string
+>f33(ts, "tag") : string
+>f33 : <S extends Shape, K extends keyof S>(shape: S, key: K) => S[K]
+>ts : TaggedShape
+>"tag" : "tag"
+
+    let tag2 = getProperty(ts, "tag");
+>tag2 : string
+>getProperty(ts, "tag") : string
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>ts : TaggedShape
+>"tag" : "tag"
+}
+
 class C {
 >C : C
 
@@ -679,3 +736,97 @@ function f40(c: C) {
 >c : C
 >"z" : "z"
 }
+
+// Repros from #12011
+
+class Base {
+>Base : Base
+
+    get<K extends keyof this>(prop: K) {
+>get : <K extends keyof this>(prop: K) => this[K]
+>K : K
+>prop : K
+>K : K
+
+        return this[prop];
+>this[prop] : this[K]
+>this : this
+>prop : K
+    }
+    set<K extends keyof this>(prop: K, value: this[K]) {
+>set : <K extends keyof this>(prop: K, value: this[K]) => void
+>K : K
+>prop : K
+>K : K
+>value : this[K]
+>K : K
+
+        this[prop] = value;
+>this[prop] = value : this[K]
+>this[prop] : this[K]
+>this : this
+>prop : K
+>value : this[K]
+    }
+}
+
+class Person extends Base {
+>Person : Person
+>Base : Base
+
+    parts: number;
+>parts : number
+
+    constructor(parts: number) {
+>parts : number
+
+        super();
+>super() : void
+>super : typeof Base
+
+        this.set("parts", parts);
+>this.set("parts", parts) : void
+>this.set : <K extends keyof this>(prop: K, value: this[K]) => void
+>this : this
+>set : <K extends keyof this>(prop: K, value: this[K]) => void
+>"parts" : "parts"
+>parts : number
+    }
+    getParts() {
+>getParts : () => number
+
+        return this.get("parts")
+>this.get("parts") : number
+>this.get : <K extends keyof this>(prop: K) => this[K]
+>this : this
+>get : <K extends keyof this>(prop: K) => this[K]
+>"parts" : "parts"
+    }
+}
+
+class OtherPerson {
+>OtherPerson : OtherPerson
+
+    parts: number;
+>parts : number
+
+    constructor(parts: number) {
+>parts : number
+
+        setProperty(this, "parts", parts);
+>setProperty(this, "parts", parts) : void
+>setProperty : <T, K extends keyof T>(obj: T, key: K, value: T[K]) => void
+>this : this
+>"parts" : "parts"
+>parts : number
+    }
+    getParts() {
+>getParts : () => number
+
+        return getProperty(this, "parts")
+>getProperty(this, "parts") : number
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>this : this
+>"parts" : "parts"
+    }
+}

From 7ed52044d11fb30e396a171847faee0fa1d5ce42 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 3 Nov 2016 10:54:07 -0700
Subject: [PATCH 164/224] Update objectRestAssignment test and baselines

---
 .../reference/objectRestAssignment.js         | 10 ++---
 .../reference/objectRestAssignment.symbols    | 40 +++++++++----------
 .../reference/objectRestAssignment.types      | 28 ++++++-------
 3 files changed, 36 insertions(+), 42 deletions(-)

diff --git a/tests/baselines/reference/objectRestAssignment.js b/tests/baselines/reference/objectRestAssignment.js
index 7ecd54c51527a..20f87ff837564 100644
--- a/tests/baselines/reference/objectRestAssignment.js
+++ b/tests/baselines/reference/objectRestAssignment.js
@@ -1,9 +1,8 @@
 //// [objectRestAssignment.ts]
-let x;
-let ka;
-let nested;
-let other;
-let rest;
+let ka: any;
+let nested: { ki };
+let other: number;
+let rest: { };
 let complex: { x: { ka, ki }, y: number };
 ({x: { ka, ...nested }, y: other, ...rest} = complex);
 
@@ -15,7 +14,6 @@ var __rest = (this && this.__rest) || function (s, e) {
         t[p] = s[p];
     return t;
 };
-var x;
 var ka;
 var nested;
 var other;
diff --git a/tests/baselines/reference/objectRestAssignment.symbols b/tests/baselines/reference/objectRestAssignment.symbols
index 3c54290b5954b..38127dbee2d2c 100644
--- a/tests/baselines/reference/objectRestAssignment.symbols
+++ b/tests/baselines/reference/objectRestAssignment.symbols
@@ -1,30 +1,28 @@
 === tests/cases/conformance/types/rest/objectRestAssignment.ts ===
-let x;
->x : Symbol(x, Decl(objectRestAssignment.ts, 0, 3))
+let ka: any;
+>ka : Symbol(ka, Decl(objectRestAssignment.ts, 0, 3))
 
-let ka;
->ka : Symbol(ka, Decl(objectRestAssignment.ts, 1, 3))
+let nested: { ki };
+>nested : Symbol(nested, Decl(objectRestAssignment.ts, 1, 3))
+>ki : Symbol(ki, Decl(objectRestAssignment.ts, 1, 13))
 
-let nested;
->nested : Symbol(nested, Decl(objectRestAssignment.ts, 2, 3))
+let other: number;
+>other : Symbol(other, Decl(objectRestAssignment.ts, 2, 3))
 
-let other;
->other : Symbol(other, Decl(objectRestAssignment.ts, 3, 3))
-
-let rest;
->rest : Symbol(rest, Decl(objectRestAssignment.ts, 4, 3))
+let rest: { };
+>rest : Symbol(rest, Decl(objectRestAssignment.ts, 3, 3))
 
 let complex: { x: { ka, ki }, y: number };
->complex : Symbol(complex, Decl(objectRestAssignment.ts, 5, 3))
->x : Symbol(x, Decl(objectRestAssignment.ts, 5, 14))
->ka : Symbol(ka, Decl(objectRestAssignment.ts, 5, 19))
->ki : Symbol(ki, Decl(objectRestAssignment.ts, 5, 23))
->y : Symbol(y, Decl(objectRestAssignment.ts, 5, 29))
+>complex : Symbol(complex, Decl(objectRestAssignment.ts, 4, 3))
+>x : Symbol(x, Decl(objectRestAssignment.ts, 4, 14))
+>ka : Symbol(ka, Decl(objectRestAssignment.ts, 4, 19))
+>ki : Symbol(ki, Decl(objectRestAssignment.ts, 4, 23))
+>y : Symbol(y, Decl(objectRestAssignment.ts, 4, 29))
 
 ({x: { ka, ...nested }, y: other, ...rest} = complex);
->x : Symbol(x, Decl(objectRestAssignment.ts, 6, 2))
->ka : Symbol(ka, Decl(objectRestAssignment.ts, 6, 6))
->y : Symbol(y, Decl(objectRestAssignment.ts, 6, 23))
->other : Symbol(other, Decl(objectRestAssignment.ts, 3, 3))
->complex : Symbol(complex, Decl(objectRestAssignment.ts, 5, 3))
+>x : Symbol(x, Decl(objectRestAssignment.ts, 5, 2))
+>ka : Symbol(ka, Decl(objectRestAssignment.ts, 5, 6))
+>y : Symbol(y, Decl(objectRestAssignment.ts, 5, 23))
+>other : Symbol(other, Decl(objectRestAssignment.ts, 2, 3))
+>complex : Symbol(complex, Decl(objectRestAssignment.ts, 4, 3))
 
diff --git a/tests/baselines/reference/objectRestAssignment.types b/tests/baselines/reference/objectRestAssignment.types
index 5af3e5872b95e..a4d88f89bb276 100644
--- a/tests/baselines/reference/objectRestAssignment.types
+++ b/tests/baselines/reference/objectRestAssignment.types
@@ -1,18 +1,16 @@
 === tests/cases/conformance/types/rest/objectRestAssignment.ts ===
-let x;
->x : any
-
-let ka;
+let ka: any;
 >ka : any
 
-let nested;
->nested : any
+let nested: { ki };
+>nested : { ki: any; }
+>ki : any
 
-let other;
->other : any
+let other: number;
+>other : number
 
-let rest;
->rest : any
+let rest: { };
+>rest : {}
 
 let complex: { x: { ka, ki }, y: number };
 >complex : { x: { ka: any; ki: any; }; y: number; }
@@ -24,13 +22,13 @@ let complex: { x: { ka, ki }, y: number };
 ({x: { ka, ...nested }, y: other, ...rest} = complex);
 >({x: { ka, ...nested }, y: other, ...rest} = complex) : { x: { ka: any; ki: any; }; y: number; }
 >{x: { ka, ...nested }, y: other, ...rest} = complex : { x: { ka: any; ki: any; }; y: number; }
->{x: { ka, ...nested }, y: other, ...rest} : { x: { ka: any; }; y: any; }
->x : { ka: any; }
->{ ka, ...nested } : { ka: any; }
+>{x: { ka, ...nested }, y: other, ...rest} : { x: { ki: any; ka: any; }; y: number; }
+>x : { ki: any; ka: any; }
+>{ ka, ...nested } : { ki: any; ka: any; }
 >ka : any
 >nested : any
->y : any
->other : any
+>y : number
+>other : number
 >rest : any
 >complex : { x: { ka: any; ki: any; }; y: number; }
 

From 6a5de5d00ee092322a1cb6d68809c37366090ee4 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 3 Nov 2016 10:55:58 -0700
Subject: [PATCH 165/224] Fix linting errors

---
 src/compiler/checker.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index b47f6264e3e9c..28b14502af98b 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -6828,7 +6828,7 @@ namespace ts {
                 if (target.flags & TypeFlags.TypeParameter) {
                     // Given a type parameter K with a constraint keyof T, a type S is
                     // assignable to K if S is assignable to keyof T.
-                    let constraint = getConstraintOfTypeParameter(<TypeParameter>target);
+                    const constraint = getConstraintOfTypeParameter(<TypeParameter>target);
                     if (constraint && constraint.flags & TypeFlags.Index) {
                         if (result = isRelatedTo(source, constraint, reportErrors)) {
                             return result;
@@ -6838,7 +6838,7 @@ namespace ts {
                 else if (target.flags & TypeFlags.Index) {
                     // Given a type parameter T with a constraint C, a type S is assignable to
                     // keyof T if S is assignable to keyof C.
-                    let constraint = getConstraintOfTypeParameter((<IndexType>target).type);
+                    const constraint = getConstraintOfTypeParameter((<IndexType>target).type);
                     if (constraint) {
                         if (result = isRelatedTo(source, getIndexType(constraint), reportErrors)) {
                             return result;

From 14f8b9990f7307484ab317c6b9016d50a26db1c7 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 3 Nov 2016 13:33:16 -0700
Subject: [PATCH 166/224] Update objectRestAssignment test

Missed previously, just got the baselines
---
 .../cases/conformance/types/rest/objectRestAssignment.ts | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/tests/cases/conformance/types/rest/objectRestAssignment.ts b/tests/cases/conformance/types/rest/objectRestAssignment.ts
index 19be53d29a3b3..4c8da304bc3c3 100644
--- a/tests/cases/conformance/types/rest/objectRestAssignment.ts
+++ b/tests/cases/conformance/types/rest/objectRestAssignment.ts
@@ -1,7 +1,6 @@
-let x;
-let ka;
-let nested;
-let other;
-let rest;
+let ka: any;
+let nested: { ki };
+let other: number;
+let rest: { };
 let complex: { x: { ka, ki }, y: number };
 ({x: { ka, ...nested }, y: other, ...rest} = complex);

From c9c5f49a24c0ea8a56af4797f710de3fec0ebd3a Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 3 Nov 2016 13:36:35 -0700
Subject: [PATCH 167/224] Improve readability of ES next destructuring emit

---
 src/compiler/transformers/destructuring.ts | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/compiler/transformers/destructuring.ts b/src/compiler/transformers/destructuring.ts
index bac8e99420115..4c9682c10b646 100644
--- a/src/compiler/transformers/destructuring.ts
+++ b/src/compiler/transformers/destructuring.ts
@@ -311,7 +311,10 @@ namespace ts {
             for (let i = 0; i < properties.length; i++) {
                 const p = properties[i];
                 if (p.kind === SyntaxKind.PropertyAssignment || p.kind === SyntaxKind.ShorthandPropertyAssignment) {
-                    if (!transformRest || p.transformFlags & TransformFlags.ContainsSpreadExpression) {
+                    if (transformRest && !(p.transformFlags & TransformFlags.ContainsSpreadExpression)) {
+                        es2015.push(p);
+                    }
+                    else {
                         if (es2015.length) {
                             emitRestAssignment(es2015, value, location, target);
                             es2015 = [];
@@ -321,9 +324,6 @@ namespace ts {
                         // Assignment for bindingTarget = value.propName should highlight whole property, hence use p as source map node
                         emitDestructuringAssignment(bindingTarget, createDestructuringPropertyAccess(value, propName), p);
                     }
-                    else {
-                        es2015.push(p);
-                    }
                 }
                 else if (i === properties.length - 1 && p.kind === SyntaxKind.SpreadElementExpression) {
                     Debug.assert((p as SpreadElementExpression).expression.kind === SyntaxKind.Identifier);
@@ -460,7 +460,11 @@ namespace ts {
                                                     name);
                     emitBindingElement(element, restCall);
                 }
-                else if (!transformRest || element.transformFlags & TransformFlags.ContainsSpreadExpression) {
+                else if (transformRest && !(element.transformFlags & TransformFlags.ContainsSpreadExpression)) {
+                    // do not emit until we have a complete bundle of ES2015 syntax
+                    es2015.push(element);
+                }
+                else {
                     if (es2015.length) {
                         emitRestAssignment(es2015, value, target, target);
                         es2015 = [];
@@ -469,10 +473,6 @@ namespace ts {
                     const propName = element.propertyName || <Identifier>element.name;
                     emitBindingElement(element, createDestructuringPropertyAccess(value, propName));
                 }
-                else {
-                    // do not emit until we have a complete bundle of ES2015 syntax
-                    es2015.push(element);
-                }
             }
             if (es2015.length) {
                 emitRestAssignment(es2015, value, target, target);

From cbec19afd76855b48c95ba09498ac21d5a17b544 Mon Sep 17 00:00:00 2001
From: Ron Buckton <rbuckton@microsoft.com>
Date: Thu, 3 Nov 2016 17:21:36 -0700
Subject: [PATCH 168/224] Ensure transformFlags are correct before visiting a
 node.

---
 src/compiler/visitor.ts                       |   2 +
 tests/baselines/reference/callWithSpread.js   |  24 ++-
 .../reference/callWithSpread.symbols          | 115 +++++++++---
 .../baselines/reference/callWithSpread.types  | 177 ++++++++++++++----
 .../functionCalls/callWithSpread.ts           |  10 +-
 5 files changed, 257 insertions(+), 71 deletions(-)

diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index 609031a82215a..45b82a6a08a2e 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -553,6 +553,7 @@ namespace ts {
             return undefined;
         }
 
+        aggregateTransformFlags(node);
         const visited = visitor(node);
         if (visited === node) {
             return node;
@@ -621,6 +622,7 @@ namespace ts {
         // Visit each original node.
         for (let i = 0; i < count; i++) {
             const node = nodes[i + start];
+            aggregateTransformFlags(node);
             const visited = node !== undefined ? visitor(node) : undefined;
             if (updated !== undefined || visited === undefined || visited !== node) {
                 if (updated === undefined) {
diff --git a/tests/baselines/reference/callWithSpread.js b/tests/baselines/reference/callWithSpread.js
index 161eb36dbcf73..69f7e4e30b0ac 100644
--- a/tests/baselines/reference/callWithSpread.js
+++ b/tests/baselines/reference/callWithSpread.js
@@ -1,6 +1,6 @@
 //// [callWithSpread.ts]
 interface X {
-    foo(x: number, y: number, ...z: string[]);
+    foo(x: number, y: number, ...z: string[]): X;
 }
 
 function foo(x: number, y: number, ...z: string[]) {
@@ -19,10 +19,18 @@ obj.foo(1, 2, "abc");
 obj.foo(1, 2, ...a);
 obj.foo(1, 2, ...a, "abc");
 
+obj.foo(1, 2, ...a).foo(1, 2, "abc");
+obj.foo(1, 2, ...a).foo(1, 2, ...a);
+obj.foo(1, 2, ...a).foo(1, 2, ...a, "abc");
+
 (obj.foo)(1, 2, "abc");
 (obj.foo)(1, 2, ...a);
 (obj.foo)(1, 2, ...a, "abc");
 
+((obj.foo)(1, 2, ...a).foo)(1, 2, "abc");
+((obj.foo)(1, 2, ...a).foo)(1, 2, ...a);
+((obj.foo)(1, 2, ...a).foo)(1, 2, ...a, "abc");
+
 xa[1].foo(1, 2, "abc");
 xa[1].foo(1, 2, ...a);
 xa[1].foo(1, 2, ...a, "abc");
@@ -72,13 +80,19 @@ foo.apply(void 0, [1, 2].concat(a, ["abc"]));
 obj.foo(1, 2, "abc");
 obj.foo.apply(obj, [1, 2].concat(a));
 obj.foo.apply(obj, [1, 2].concat(a, ["abc"]));
+obj.foo.apply(obj, [1, 2].concat(a)).foo(1, 2, "abc");
+(_a = obj.foo.apply(obj, [1, 2].concat(a))).foo.apply(_a, [1, 2].concat(a));
+(_b = obj.foo.apply(obj, [1, 2].concat(a))).foo.apply(_b, [1, 2].concat(a, ["abc"]));
 (obj.foo)(1, 2, "abc");
 obj.foo.apply(obj, [1, 2].concat(a));
 obj.foo.apply(obj, [1, 2].concat(a, ["abc"]));
+(obj.foo.apply(obj, [1, 2].concat(a)).foo)(1, 2, "abc");
+(_c = obj.foo.apply(obj, [1, 2].concat(a))).foo.apply(_c, [1, 2].concat(a));
+(_d = obj.foo.apply(obj, [1, 2].concat(a))).foo.apply(_d, [1, 2].concat(a, ["abc"]));
 xa[1].foo(1, 2, "abc");
-(_a = xa[1]).foo.apply(_a, [1, 2].concat(a));
-(_b = xa[1]).foo.apply(_b, [1, 2].concat(a, ["abc"]));
-(_c = xa[1]).foo.apply(_c, [1, 2, "abc"]);
+(_e = xa[1]).foo.apply(_e, [1, 2].concat(a));
+(_f = xa[1]).foo.apply(_f, [1, 2].concat(a, ["abc"]));
+(_g = xa[1]).foo.apply(_g, [1, 2, "abc"]);
 var C = (function () {
     function C(x, y) {
         var z = [];
@@ -109,4 +123,4 @@ var D = (function (_super) {
     };
     return D;
 }(C));
-var _a, _b, _c;
+var _a, _b, _c, _d, _e, _f, _g;
diff --git a/tests/baselines/reference/callWithSpread.symbols b/tests/baselines/reference/callWithSpread.symbols
index bc2d9bfebd990..42331422df723 100644
--- a/tests/baselines/reference/callWithSpread.symbols
+++ b/tests/baselines/reference/callWithSpread.symbols
@@ -2,11 +2,12 @@
 interface X {
 >X : Symbol(X, Decl(callWithSpread.ts, 0, 0))
 
-    foo(x: number, y: number, ...z: string[]);
+    foo(x: number, y: number, ...z: string[]): X;
 >foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
 >x : Symbol(x, Decl(callWithSpread.ts, 1, 8))
 >y : Symbol(y, Decl(callWithSpread.ts, 1, 18))
 >z : Symbol(z, Decl(callWithSpread.ts, 1, 29))
+>X : Symbol(X, Decl(callWithSpread.ts, 0, 0))
 }
 
 function foo(x: number, y: number, ...z: string[]) {
@@ -58,6 +59,32 @@ obj.foo(1, 2, ...a, "abc");
 >foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
 >a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
 
+obj.foo(1, 2, ...a).foo(1, 2, "abc");
+>obj.foo(1, 2, ...a).foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>obj.foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>obj : Symbol(obj, Decl(callWithSpread.ts, 9, 3))
+>foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
+>foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+
+obj.foo(1, 2, ...a).foo(1, 2, ...a);
+>obj.foo(1, 2, ...a).foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>obj.foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>obj : Symbol(obj, Decl(callWithSpread.ts, 9, 3))
+>foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
+>foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
+
+obj.foo(1, 2, ...a).foo(1, 2, ...a, "abc");
+>obj.foo(1, 2, ...a).foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>obj.foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>obj : Symbol(obj, Decl(callWithSpread.ts, 9, 3))
+>foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
+>foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
+
 (obj.foo)(1, 2, "abc");
 >obj.foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
 >obj : Symbol(obj, Decl(callWithSpread.ts, 9, 3))
@@ -75,6 +102,32 @@ obj.foo(1, 2, ...a, "abc");
 >foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
 >a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
 
+((obj.foo)(1, 2, ...a).foo)(1, 2, "abc");
+>(obj.foo)(1, 2, ...a).foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>obj.foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>obj : Symbol(obj, Decl(callWithSpread.ts, 9, 3))
+>foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
+>foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+
+((obj.foo)(1, 2, ...a).foo)(1, 2, ...a);
+>(obj.foo)(1, 2, ...a).foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>obj.foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>obj : Symbol(obj, Decl(callWithSpread.ts, 9, 3))
+>foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
+>foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
+
+((obj.foo)(1, 2, ...a).foo)(1, 2, ...a, "abc");
+>(obj.foo)(1, 2, ...a).foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>obj.foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>obj : Symbol(obj, Decl(callWithSpread.ts, 9, 3))
+>foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
+>foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
+>a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
+
 xa[1].foo(1, 2, "abc");
 >xa[1].foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
 >xa : Symbol(xa, Decl(callWithSpread.ts, 10, 3))
@@ -99,60 +152,60 @@ xa[1].foo(1, 2, ...a, "abc");
 >foo : Symbol(X.foo, Decl(callWithSpread.ts, 0, 13))
 
 class C {
->C : Symbol(C, Decl(callWithSpread.ts, 28, 40))
+>C : Symbol(C, Decl(callWithSpread.ts, 36, 40))
 
     constructor(x: number, y: number, ...z: string[]) {
->x : Symbol(x, Decl(callWithSpread.ts, 31, 16))
->y : Symbol(y, Decl(callWithSpread.ts, 31, 26))
->z : Symbol(z, Decl(callWithSpread.ts, 31, 37))
+>x : Symbol(x, Decl(callWithSpread.ts, 39, 16))
+>y : Symbol(y, Decl(callWithSpread.ts, 39, 26))
+>z : Symbol(z, Decl(callWithSpread.ts, 39, 37))
 
         this.foo(x, y);
->this.foo : Symbol(C.foo, Decl(callWithSpread.ts, 34, 5))
->this : Symbol(C, Decl(callWithSpread.ts, 28, 40))
->foo : Symbol(C.foo, Decl(callWithSpread.ts, 34, 5))
->x : Symbol(x, Decl(callWithSpread.ts, 31, 16))
->y : Symbol(y, Decl(callWithSpread.ts, 31, 26))
+>this.foo : Symbol(C.foo, Decl(callWithSpread.ts, 42, 5))
+>this : Symbol(C, Decl(callWithSpread.ts, 36, 40))
+>foo : Symbol(C.foo, Decl(callWithSpread.ts, 42, 5))
+>x : Symbol(x, Decl(callWithSpread.ts, 39, 16))
+>y : Symbol(y, Decl(callWithSpread.ts, 39, 26))
 
         this.foo(x, y, ...z);
->this.foo : Symbol(C.foo, Decl(callWithSpread.ts, 34, 5))
->this : Symbol(C, Decl(callWithSpread.ts, 28, 40))
->foo : Symbol(C.foo, Decl(callWithSpread.ts, 34, 5))
->x : Symbol(x, Decl(callWithSpread.ts, 31, 16))
->y : Symbol(y, Decl(callWithSpread.ts, 31, 26))
->z : Symbol(z, Decl(callWithSpread.ts, 31, 37))
+>this.foo : Symbol(C.foo, Decl(callWithSpread.ts, 42, 5))
+>this : Symbol(C, Decl(callWithSpread.ts, 36, 40))
+>foo : Symbol(C.foo, Decl(callWithSpread.ts, 42, 5))
+>x : Symbol(x, Decl(callWithSpread.ts, 39, 16))
+>y : Symbol(y, Decl(callWithSpread.ts, 39, 26))
+>z : Symbol(z, Decl(callWithSpread.ts, 39, 37))
     }
     foo(x: number, y: number, ...z: string[]) {
->foo : Symbol(C.foo, Decl(callWithSpread.ts, 34, 5))
->x : Symbol(x, Decl(callWithSpread.ts, 35, 8))
->y : Symbol(y, Decl(callWithSpread.ts, 35, 18))
->z : Symbol(z, Decl(callWithSpread.ts, 35, 29))
+>foo : Symbol(C.foo, Decl(callWithSpread.ts, 42, 5))
+>x : Symbol(x, Decl(callWithSpread.ts, 43, 8))
+>y : Symbol(y, Decl(callWithSpread.ts, 43, 18))
+>z : Symbol(z, Decl(callWithSpread.ts, 43, 29))
     }
 }
 
 class D extends C {
->D : Symbol(D, Decl(callWithSpread.ts, 37, 1))
->C : Symbol(C, Decl(callWithSpread.ts, 28, 40))
+>D : Symbol(D, Decl(callWithSpread.ts, 45, 1))
+>C : Symbol(C, Decl(callWithSpread.ts, 36, 40))
 
     constructor() {
         super(1, 2);
->super : Symbol(C, Decl(callWithSpread.ts, 28, 40))
+>super : Symbol(C, Decl(callWithSpread.ts, 36, 40))
 
         super(1, 2, ...a);
->super : Symbol(C, Decl(callWithSpread.ts, 28, 40))
+>super : Symbol(C, Decl(callWithSpread.ts, 36, 40))
 >a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
     }
     foo() {
->foo : Symbol(D.foo, Decl(callWithSpread.ts, 43, 5))
+>foo : Symbol(D.foo, Decl(callWithSpread.ts, 51, 5))
 
         super.foo(1, 2);
->super.foo : Symbol(C.foo, Decl(callWithSpread.ts, 34, 5))
->super : Symbol(C, Decl(callWithSpread.ts, 28, 40))
->foo : Symbol(C.foo, Decl(callWithSpread.ts, 34, 5))
+>super.foo : Symbol(C.foo, Decl(callWithSpread.ts, 42, 5))
+>super : Symbol(C, Decl(callWithSpread.ts, 36, 40))
+>foo : Symbol(C.foo, Decl(callWithSpread.ts, 42, 5))
 
         super.foo(1, 2, ...a);
->super.foo : Symbol(C.foo, Decl(callWithSpread.ts, 34, 5))
->super : Symbol(C, Decl(callWithSpread.ts, 28, 40))
->foo : Symbol(C.foo, Decl(callWithSpread.ts, 34, 5))
+>super.foo : Symbol(C.foo, Decl(callWithSpread.ts, 42, 5))
+>super : Symbol(C, Decl(callWithSpread.ts, 36, 40))
+>foo : Symbol(C.foo, Decl(callWithSpread.ts, 42, 5))
 >a : Symbol(a, Decl(callWithSpread.ts, 7, 3))
     }
 }
diff --git a/tests/baselines/reference/callWithSpread.types b/tests/baselines/reference/callWithSpread.types
index c9403f1bb69d4..5af9d2fef846e 100644
--- a/tests/baselines/reference/callWithSpread.types
+++ b/tests/baselines/reference/callWithSpread.types
@@ -2,11 +2,12 @@
 interface X {
 >X : X
 
-    foo(x: number, y: number, ...z: string[]);
->foo : (x: number, y: number, ...z: string[]) => any
+    foo(x: number, y: number, ...z: string[]): X;
+>foo : (x: number, y: number, ...z: string[]) => X
 >x : number
 >y : number
 >z : string[]
+>X : X
 }
 
 function foo(x: number, y: number, ...z: string[]) {
@@ -55,29 +56,80 @@ foo(1, 2, ...a, "abc");
 >"abc" : "abc"
 
 obj.foo(1, 2, "abc");
->obj.foo(1, 2, "abc") : any
->obj.foo : (x: number, y: number, ...z: string[]) => any
+>obj.foo(1, 2, "abc") : X
+>obj.foo : (x: number, y: number, ...z: string[]) => X
 >obj : X
->foo : (x: number, y: number, ...z: string[]) => any
+>foo : (x: number, y: number, ...z: string[]) => X
 >1 : 1
 >2 : 2
 >"abc" : "abc"
 
 obj.foo(1, 2, ...a);
->obj.foo(1, 2, ...a) : any
->obj.foo : (x: number, y: number, ...z: string[]) => any
+>obj.foo(1, 2, ...a) : X
+>obj.foo : (x: number, y: number, ...z: string[]) => X
 >obj : X
->foo : (x: number, y: number, ...z: string[]) => any
+>foo : (x: number, y: number, ...z: string[]) => X
 >1 : 1
 >2 : 2
 >...a : string
 >a : string[]
 
 obj.foo(1, 2, ...a, "abc");
->obj.foo(1, 2, ...a, "abc") : any
->obj.foo : (x: number, y: number, ...z: string[]) => any
+>obj.foo(1, 2, ...a, "abc") : X
+>obj.foo : (x: number, y: number, ...z: string[]) => X
+>obj : X
+>foo : (x: number, y: number, ...z: string[]) => X
+>1 : 1
+>2 : 2
+>...a : string
+>a : string[]
+>"abc" : "abc"
+
+obj.foo(1, 2, ...a).foo(1, 2, "abc");
+>obj.foo(1, 2, ...a).foo(1, 2, "abc") : X
+>obj.foo(1, 2, ...a).foo : (x: number, y: number, ...z: string[]) => X
+>obj.foo(1, 2, ...a) : X
+>obj.foo : (x: number, y: number, ...z: string[]) => X
 >obj : X
->foo : (x: number, y: number, ...z: string[]) => any
+>foo : (x: number, y: number, ...z: string[]) => X
+>1 : 1
+>2 : 2
+>...a : string
+>a : string[]
+>foo : (x: number, y: number, ...z: string[]) => X
+>1 : 1
+>2 : 2
+>"abc" : "abc"
+
+obj.foo(1, 2, ...a).foo(1, 2, ...a);
+>obj.foo(1, 2, ...a).foo(1, 2, ...a) : X
+>obj.foo(1, 2, ...a).foo : (x: number, y: number, ...z: string[]) => X
+>obj.foo(1, 2, ...a) : X
+>obj.foo : (x: number, y: number, ...z: string[]) => X
+>obj : X
+>foo : (x: number, y: number, ...z: string[]) => X
+>1 : 1
+>2 : 2
+>...a : string
+>a : string[]
+>foo : (x: number, y: number, ...z: string[]) => X
+>1 : 1
+>2 : 2
+>...a : string
+>a : string[]
+
+obj.foo(1, 2, ...a).foo(1, 2, ...a, "abc");
+>obj.foo(1, 2, ...a).foo(1, 2, ...a, "abc") : X
+>obj.foo(1, 2, ...a).foo : (x: number, y: number, ...z: string[]) => X
+>obj.foo(1, 2, ...a) : X
+>obj.foo : (x: number, y: number, ...z: string[]) => X
+>obj : X
+>foo : (x: number, y: number, ...z: string[]) => X
+>1 : 1
+>2 : 2
+>...a : string
+>a : string[]
+>foo : (x: number, y: number, ...z: string[]) => X
 >1 : 1
 >2 : 2
 >...a : string
@@ -85,32 +137,89 @@ obj.foo(1, 2, ...a, "abc");
 >"abc" : "abc"
 
 (obj.foo)(1, 2, "abc");
->(obj.foo)(1, 2, "abc") : any
->(obj.foo) : (x: number, y: number, ...z: string[]) => any
->obj.foo : (x: number, y: number, ...z: string[]) => any
+>(obj.foo)(1, 2, "abc") : X
+>(obj.foo) : (x: number, y: number, ...z: string[]) => X
+>obj.foo : (x: number, y: number, ...z: string[]) => X
 >obj : X
->foo : (x: number, y: number, ...z: string[]) => any
+>foo : (x: number, y: number, ...z: string[]) => X
 >1 : 1
 >2 : 2
 >"abc" : "abc"
 
 (obj.foo)(1, 2, ...a);
->(obj.foo)(1, 2, ...a) : any
->(obj.foo) : (x: number, y: number, ...z: string[]) => any
->obj.foo : (x: number, y: number, ...z: string[]) => any
+>(obj.foo)(1, 2, ...a) : X
+>(obj.foo) : (x: number, y: number, ...z: string[]) => X
+>obj.foo : (x: number, y: number, ...z: string[]) => X
 >obj : X
->foo : (x: number, y: number, ...z: string[]) => any
+>foo : (x: number, y: number, ...z: string[]) => X
 >1 : 1
 >2 : 2
 >...a : string
 >a : string[]
 
 (obj.foo)(1, 2, ...a, "abc");
->(obj.foo)(1, 2, ...a, "abc") : any
->(obj.foo) : (x: number, y: number, ...z: string[]) => any
->obj.foo : (x: number, y: number, ...z: string[]) => any
+>(obj.foo)(1, 2, ...a, "abc") : X
+>(obj.foo) : (x: number, y: number, ...z: string[]) => X
+>obj.foo : (x: number, y: number, ...z: string[]) => X
 >obj : X
->foo : (x: number, y: number, ...z: string[]) => any
+>foo : (x: number, y: number, ...z: string[]) => X
+>1 : 1
+>2 : 2
+>...a : string
+>a : string[]
+>"abc" : "abc"
+
+((obj.foo)(1, 2, ...a).foo)(1, 2, "abc");
+>((obj.foo)(1, 2, ...a).foo)(1, 2, "abc") : X
+>((obj.foo)(1, 2, ...a).foo) : (x: number, y: number, ...z: string[]) => X
+>(obj.foo)(1, 2, ...a).foo : (x: number, y: number, ...z: string[]) => X
+>(obj.foo)(1, 2, ...a) : X
+>(obj.foo) : (x: number, y: number, ...z: string[]) => X
+>obj.foo : (x: number, y: number, ...z: string[]) => X
+>obj : X
+>foo : (x: number, y: number, ...z: string[]) => X
+>1 : 1
+>2 : 2
+>...a : string
+>a : string[]
+>foo : (x: number, y: number, ...z: string[]) => X
+>1 : 1
+>2 : 2
+>"abc" : "abc"
+
+((obj.foo)(1, 2, ...a).foo)(1, 2, ...a);
+>((obj.foo)(1, 2, ...a).foo)(1, 2, ...a) : X
+>((obj.foo)(1, 2, ...a).foo) : (x: number, y: number, ...z: string[]) => X
+>(obj.foo)(1, 2, ...a).foo : (x: number, y: number, ...z: string[]) => X
+>(obj.foo)(1, 2, ...a) : X
+>(obj.foo) : (x: number, y: number, ...z: string[]) => X
+>obj.foo : (x: number, y: number, ...z: string[]) => X
+>obj : X
+>foo : (x: number, y: number, ...z: string[]) => X
+>1 : 1
+>2 : 2
+>...a : string
+>a : string[]
+>foo : (x: number, y: number, ...z: string[]) => X
+>1 : 1
+>2 : 2
+>...a : string
+>a : string[]
+
+((obj.foo)(1, 2, ...a).foo)(1, 2, ...a, "abc");
+>((obj.foo)(1, 2, ...a).foo)(1, 2, ...a, "abc") : X
+>((obj.foo)(1, 2, ...a).foo) : (x: number, y: number, ...z: string[]) => X
+>(obj.foo)(1, 2, ...a).foo : (x: number, y: number, ...z: string[]) => X
+>(obj.foo)(1, 2, ...a) : X
+>(obj.foo) : (x: number, y: number, ...z: string[]) => X
+>obj.foo : (x: number, y: number, ...z: string[]) => X
+>obj : X
+>foo : (x: number, y: number, ...z: string[]) => X
+>1 : 1
+>2 : 2
+>...a : string
+>a : string[]
+>foo : (x: number, y: number, ...z: string[]) => X
 >1 : 1
 >2 : 2
 >...a : string
@@ -118,35 +227,35 @@ obj.foo(1, 2, ...a, "abc");
 >"abc" : "abc"
 
 xa[1].foo(1, 2, "abc");
->xa[1].foo(1, 2, "abc") : any
->xa[1].foo : (x: number, y: number, ...z: string[]) => any
+>xa[1].foo(1, 2, "abc") : X
+>xa[1].foo : (x: number, y: number, ...z: string[]) => X
 >xa[1] : X
 >xa : X[]
 >1 : 1
->foo : (x: number, y: number, ...z: string[]) => any
+>foo : (x: number, y: number, ...z: string[]) => X
 >1 : 1
 >2 : 2
 >"abc" : "abc"
 
 xa[1].foo(1, 2, ...a);
->xa[1].foo(1, 2, ...a) : any
->xa[1].foo : (x: number, y: number, ...z: string[]) => any
+>xa[1].foo(1, 2, ...a) : X
+>xa[1].foo : (x: number, y: number, ...z: string[]) => X
 >xa[1] : X
 >xa : X[]
 >1 : 1
->foo : (x: number, y: number, ...z: string[]) => any
+>foo : (x: number, y: number, ...z: string[]) => X
 >1 : 1
 >2 : 2
 >...a : string
 >a : string[]
 
 xa[1].foo(1, 2, ...a, "abc");
->xa[1].foo(1, 2, ...a, "abc") : any
->xa[1].foo : (x: number, y: number, ...z: string[]) => any
+>xa[1].foo(1, 2, ...a, "abc") : X
+>xa[1].foo : (x: number, y: number, ...z: string[]) => X
 >xa[1] : X
 >xa : X[]
 >1 : 1
->foo : (x: number, y: number, ...z: string[]) => any
+>foo : (x: number, y: number, ...z: string[]) => X
 >1 : 1
 >2 : 2
 >...a : string
@@ -158,11 +267,11 @@ xa[1].foo(1, 2, ...a, "abc");
 >(<Function>xa[1].foo) : Function
 ><Function>xa[1].foo : Function
 >Function : Function
->xa[1].foo : (x: number, y: number, ...z: string[]) => any
+>xa[1].foo : (x: number, y: number, ...z: string[]) => X
 >xa[1] : X
 >xa : X[]
 >1 : 1
->foo : (x: number, y: number, ...z: string[]) => any
+>foo : (x: number, y: number, ...z: string[]) => X
 >...[1, 2, "abc"] : string | number
 >[1, 2, "abc"] : (string | number)[]
 >1 : 1
diff --git a/tests/cases/conformance/expressions/functionCalls/callWithSpread.ts b/tests/cases/conformance/expressions/functionCalls/callWithSpread.ts
index 245028db3d425..b1e2ee757848c 100644
--- a/tests/cases/conformance/expressions/functionCalls/callWithSpread.ts
+++ b/tests/cases/conformance/expressions/functionCalls/callWithSpread.ts
@@ -1,5 +1,5 @@
 interface X {
-    foo(x: number, y: number, ...z: string[]);
+    foo(x: number, y: number, ...z: string[]): X;
 }
 
 function foo(x: number, y: number, ...z: string[]) {
@@ -18,10 +18,18 @@ obj.foo(1, 2, "abc");
 obj.foo(1, 2, ...a);
 obj.foo(1, 2, ...a, "abc");
 
+obj.foo(1, 2, ...a).foo(1, 2, "abc");
+obj.foo(1, 2, ...a).foo(1, 2, ...a);
+obj.foo(1, 2, ...a).foo(1, 2, ...a, "abc");
+
 (obj.foo)(1, 2, "abc");
 (obj.foo)(1, 2, ...a);
 (obj.foo)(1, 2, ...a, "abc");
 
+((obj.foo)(1, 2, ...a).foo)(1, 2, "abc");
+((obj.foo)(1, 2, ...a).foo)(1, 2, ...a);
+((obj.foo)(1, 2, ...a).foo)(1, 2, ...a, "abc");
+
 xa[1].foo(1, 2, "abc");
 xa[1].foo(1, 2, ...a);
 xa[1].foo(1, 2, ...a, "abc");

From 1c004bf317a3e9103572668191055ba1c86f1788 Mon Sep 17 00:00:00 2001
From: Zhengbo Li <zhengbli@microsoft.com>
Date: Thu, 3 Nov 2016 21:13:41 -0700
Subject: [PATCH 169/224] Port #12027, #11980 and #11932 to master (#12037)

* add test for the fix for overwrite emitting error

* cr feedback
---
 src/compiler/core.ts                          | 12 +++++++++
 src/compiler/diagnosticMessages.json          |  4 +++
 src/compiler/program.ts                       | 25 ++++++++++++++-----
 src/compiler/types.ts                         |  1 +
 src/harness/fourslash.ts                      | 13 +++++++++-
 .../unittests/tsserverProjectSystem.ts        | 24 ++++++++++++++++++
 src/server/project.ts                         |  4 +++
 ...sWhenEmitBlockingErrorOnOtherFile.baseline |  3 ++-
 .../declarationFileOverwriteError.errors.txt  |  2 ++
 ...rationFileOverwriteErrorWithOut.errors.txt |  2 ++
 .../exportDefaultInJsFile01.errors.txt        |  2 ++
 .../exportDefaultInJsFile02.errors.txt        |  2 ++
 ...tionAmbientVarDeclarationSyntax.errors.txt |  2 ++
 ...CompilationEmitBlockedCorrectly.errors.txt |  2 ++
 .../jsFileCompilationEnumSyntax.errors.txt    |  2 ++
 ...onsWithJsFileReferenceWithNoOut.errors.txt |  2 ++
 ...mpilationExportAssignmentSyntax.errors.txt |  2 ++
 ...tionHeritageClauseSyntaxOfClass.errors.txt |  2 ++
 ...leCompilationImportEqualsSyntax.errors.txt |  2 ++
 ...sFileCompilationInterfaceSyntax.errors.txt |  2 ++
 .../jsFileCompilationModuleSyntax.errors.txt  |  2 ++
 ...onsWithJsFileReferenceWithNoOut.errors.txt |  2 ++
 ...ileCompilationOptionalParameter.errors.txt |  2 ++
 ...lationPublicMethodSyntaxOfClass.errors.txt |  2 ++
 ...pilationPublicParameterModifier.errors.txt |  2 ++
 ...ationReturnTypeSyntaxOfFunction.errors.txt |  2 ++
 .../jsFileCompilationSyntaxError.errors.txt   |  2 ++
 ...sFileCompilationTypeAliasSyntax.errors.txt |  2 ++
 ...ilationTypeArgumentSyntaxOfCall.errors.txt |  2 ++
 ...jsFileCompilationTypeAssertions.errors.txt |  2 ++
 ...sFileCompilationTypeOfParameter.errors.txt |  2 ++
 ...ationTypeParameterSyntaxOfClass.errors.txt |  2 ++
 ...onTypeParameterSyntaxOfFunction.errors.txt |  2 ++
 ...sFileCompilationTypeSyntaxOfVar.errors.txt |  2 ++
 ...hDeclarationEmitPathSameAsInput.errors.txt |  2 ++
 ...lationWithJsEmitPathSameAsInput.errors.txt |  2 ++
 ...sFileCompilationWithMapFileAsJs.errors.txt |  2 ++
 ...hMapFileAsJsWithInlineSourceMap.errors.txt |  2 ++
 ...rationFileNameSameAsInputJsFile.errors.txt |  2 ++
 ...ithOutFileNameSameAsInputJsFile.errors.txt |  2 ++
 .../jsFileCompilationWithoutOut.errors.txt    |  2 ++
 ...eNameDtsNotSpecifiedWithAllowJs.errors.txt |  2 ++
 ...eNameDtsNotSpecifiedWithAllowJs.errors.txt |  2 ++
 43 files changed, 148 insertions(+), 8 deletions(-)

diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index dd71877930a62..8175730159b0b 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -1127,6 +1127,18 @@ namespace ts {
         };
     }
 
+    export function createCompilerDiagnosticFromMessageChain(chain: DiagnosticMessageChain): Diagnostic {
+        return {
+            file: undefined,
+            start: undefined,
+            length: undefined,
+
+            code: chain.code,
+            category: chain.category,
+            messageText: chain.next ? chain : chain.messageText
+        };
+    }
+
     export function chainDiagnosticMessages(details: DiagnosticMessageChain, message: DiagnosticMessage, ...args: any[]): DiagnosticMessageChain;
     export function chainDiagnosticMessages(details: DiagnosticMessageChain, message: DiagnosticMessage): DiagnosticMessageChain {
         let text = getLocaleSpecificMessage(message);
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 5290782c156a2..9a353e6fb3651 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -3158,5 +3158,9 @@
     "Implement inherited abstract class": {
         "category": "Message",
         "code": 90007
+    },
+    "Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig": {
+        "category": "Error",
+        "code": 90009
     }
 }
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 82d274e0487df..dcb9cce0adb55 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -239,11 +239,11 @@ namespace ts {
                 const { line, character } = getLineAndCharacterOfPosition(diagnostic.file, diagnostic.start);
                 const fileName = diagnostic.file.fileName;
                 const relativeFileName = convertToRelativePath(fileName, host.getCurrentDirectory(), fileName => host.getCanonicalFileName(fileName));
-                output += `${ relativeFileName }(${ line + 1 },${ character + 1 }): `;
+                output += `${relativeFileName}(${line + 1},${character + 1}): `;
             }
 
             const category = DiagnosticCategory[diagnostic.category].toLowerCase();
-            output += `${ category } TS${ diagnostic.code }: ${ flattenDiagnosticMessageText(diagnostic.messageText, host.getNewLine()) }${ host.getNewLine() }`;
+            output += `${category} TS${diagnostic.code}: ${flattenDiagnosticMessageText(diagnostic.messageText, host.getNewLine())}${host.getNewLine()}`;
         }
         return output;
     }
@@ -1685,13 +1685,24 @@ namespace ts {
                     const emitFilePath = toPath(emitFileName, currentDirectory, getCanonicalFileName);
                     // Report error if the output overwrites input file
                     if (filesByName.contains(emitFilePath)) {
-                        createEmitBlockingDiagnostics(emitFileName, Diagnostics.Cannot_write_file_0_because_it_would_overwrite_input_file);
+                        if (options.noEmitOverwritenFiles && !options.out && !options.outDir && !options.outFile) {
+                            blockEmittingOfFile(emitFileName);
+                        }
+                        else {
+                            let chain: DiagnosticMessageChain;
+                            if (!options.configFilePath) {
+                                // The program is from either an inferred project or an external project
+                                chain = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Adding_a_tsconfig_json_file_will_help_organize_projects_that_contain_both_TypeScript_and_JavaScript_files_Learn_more_at_https_Colon_Slash_Slashaka_ms_Slashtsconfig);
+                            }
+                            chain = chainDiagnosticMessages(chain, Diagnostics.Cannot_write_file_0_because_it_would_overwrite_input_file, emitFileName);
+                            blockEmittingOfFile(emitFileName, createCompilerDiagnosticFromMessageChain(chain));
+                        }
                     }
 
                     // Report error if multiple files write into same file
                     if (emitFilesSeen.contains(emitFilePath)) {
                         // Already seen the same emit file - report error
-                        createEmitBlockingDiagnostics(emitFileName, Diagnostics.Cannot_write_file_0_because_it_would_be_overwritten_by_multiple_input_files);
+                        blockEmittingOfFile(emitFileName, createCompilerDiagnostic(Diagnostics.Cannot_write_file_0_because_it_would_be_overwritten_by_multiple_input_files, emitFileName));
                     }
                     else {
                         emitFilesSeen.set(emitFilePath, true);
@@ -1700,9 +1711,11 @@ namespace ts {
             }
         }
 
-        function createEmitBlockingDiagnostics(emitFileName: string, message: DiagnosticMessage) {
+        function blockEmittingOfFile(emitFileName: string, diag?: Diagnostic) {
             hasEmitBlockingDiagnostics.set(toPath(emitFileName, currentDirectory, getCanonicalFileName), true);
-            programDiagnostics.add(createCompilerDiagnostic(message, emitFileName));
+            if (diag) {
+                programDiagnostics.add(diag);
+            }
         }
     }
 
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index b865beca76b9a..5536a818df536 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -3058,6 +3058,7 @@ namespace ts {
         moduleResolution?: ModuleResolutionKind;
         newLine?: NewLineKind;
         noEmit?: boolean;
+        /*@internal*/noEmitOverwritenFiles?: boolean;
         noEmitHelpers?: boolean;
         noEmitOnError?: boolean;
         noErrorTruncation?: boolean;
diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index b008ca653702d..ae32fe3db1631 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -1253,7 +1253,18 @@ namespace FourSlash {
                             resultString += "Diagnostics:" + Harness.IO.newLine();
                             const diagnostics = ts.getPreEmitDiagnostics(this.languageService.getProgram());
                             for (const diagnostic of diagnostics) {
-                                resultString += "  " + diagnostic.messageText + Harness.IO.newLine();
+                                if (typeof diagnostic.messageText !== "string") {
+                                    let chainedMessage = <ts.DiagnosticMessageChain>diagnostic.messageText;
+                                    let indentation = " ";
+                                    while (chainedMessage) {
+                                        resultString += indentation + chainedMessage.messageText + Harness.IO.newLine();
+                                        chainedMessage = chainedMessage.next;
+                                        indentation = indentation + " ";
+                                    }
+                                }
+                                else {
+                                    resultString += "  " + diagnostic.messageText + Harness.IO.newLine();
+                                }
                             }
                         }
 
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index 870926a8c5595..15cfa3f8c8e7c 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -2505,4 +2505,28 @@ namespace ts.projectSystem {
             checkProjectActualFiles(projectService.inferredProjects[0], [f.path]);
         });
     });
+
+    describe("No overwrite emit error", () => {
+        it("for inferred project", () => {
+            const f1 = {
+                path: "/a/b/f1.js",
+                content: "function test1() { }"
+            };
+            const host = createServerHost([f1, libFile]);
+            const session = createSession(host);
+            openFilesForSession([f1], session);
+
+            const projectService = session.getProjectService();
+            checkNumberOfProjects(projectService, { inferredProjects: 1 });
+            const projectName = projectService.inferredProjects[0].getProjectName();
+
+            const diags = session.executeCommand(<server.protocol.CompilerOptionsDiagnosticsRequest>{
+                type: "request",
+                command: server.CommandNames.CompilerOptionsDiagnosticsFull,
+                seq: 2,
+                arguments: { projectFileName: projectName }
+            }).response;
+            assert.isTrue(diags.length === 0);
+        });
+    });
 }
\ No newline at end of file
diff --git a/src/server/project.ts b/src/server/project.ts
index 457f5e2b261df..563b045691071 100644
--- a/src/server/project.ts
+++ b/src/server/project.ts
@@ -161,6 +161,10 @@ namespace ts.server {
                 this.compilerOptions.allowNonTsExtensions = true;
             }
 
+            if (this.projectKind === ProjectKind.Inferred) {
+                this.compilerOptions.noEmitOverwritenFiles = true;
+            }
+
             if (languageServiceEnabled) {
                 this.enableLanguageService();
             }
diff --git a/tests/baselines/reference/compileOnSaveWorksWhenEmitBlockingErrorOnOtherFile.baseline b/tests/baselines/reference/compileOnSaveWorksWhenEmitBlockingErrorOnOtherFile.baseline
index a088006d1450e..f8b479e6d7b7b 100644
--- a/tests/baselines/reference/compileOnSaveWorksWhenEmitBlockingErrorOnOtherFile.baseline
+++ b/tests/baselines/reference/compileOnSaveWorksWhenEmitBlockingErrorOnOtherFile.baseline
@@ -1,6 +1,7 @@
 EmitSkipped: true
 Diagnostics:
-  Cannot write file '/tests/cases/fourslash/b.js' because it would overwrite input file.
+ Cannot write file '/tests/cases/fourslash/b.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 EmitSkipped: false
 FileName : /tests/cases/fourslash/a.js
diff --git a/tests/baselines/reference/declarationFileOverwriteError.errors.txt b/tests/baselines/reference/declarationFileOverwriteError.errors.txt
index 1974976dee1fe..211469778b1fe 100644
--- a/tests/baselines/reference/declarationFileOverwriteError.errors.txt
+++ b/tests/baselines/reference/declarationFileOverwriteError.errors.txt
@@ -1,7 +1,9 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.d.ts' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.d.ts' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.d.ts (0 errors) ====
     
     declare class c {
diff --git a/tests/baselines/reference/declarationFileOverwriteErrorWithOut.errors.txt b/tests/baselines/reference/declarationFileOverwriteErrorWithOut.errors.txt
index 658465de9c2d2..ea4a93b3b12db 100644
--- a/tests/baselines/reference/declarationFileOverwriteErrorWithOut.errors.txt
+++ b/tests/baselines/reference/declarationFileOverwriteErrorWithOut.errors.txt
@@ -1,7 +1,9 @@
 error TS5055: Cannot write file 'tests/cases/compiler/out.d.ts' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/out.d.ts' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/out.d.ts (0 errors) ====
     
     declare class c {
diff --git a/tests/baselines/reference/exportDefaultInJsFile01.errors.txt b/tests/baselines/reference/exportDefaultInJsFile01.errors.txt
index 34035e1e14e73..0565c8bd61ef2 100644
--- a/tests/baselines/reference/exportDefaultInJsFile01.errors.txt
+++ b/tests/baselines/reference/exportDefaultInJsFile01.errors.txt
@@ -1,7 +1,9 @@
 error TS5055: Cannot write file 'tests/cases/conformance/salsa/myFile01.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5055: Cannot write file 'tests/cases/conformance/salsa/myFile01.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/conformance/salsa/myFile01.js (0 errors) ====
     
     export default "hello";
\ No newline at end of file
diff --git a/tests/baselines/reference/exportDefaultInJsFile02.errors.txt b/tests/baselines/reference/exportDefaultInJsFile02.errors.txt
index 5e17306e066f5..a74fbacfcfd87 100644
--- a/tests/baselines/reference/exportDefaultInJsFile02.errors.txt
+++ b/tests/baselines/reference/exportDefaultInJsFile02.errors.txt
@@ -1,7 +1,9 @@
 error TS5055: Cannot write file 'tests/cases/conformance/salsa/myFile02.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5055: Cannot write file 'tests/cases/conformance/salsa/myFile02.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/conformance/salsa/myFile02.js (0 errors) ====
     
     export default "hello";
\ No newline at end of file
diff --git a/tests/baselines/reference/jsFileCompilationAmbientVarDeclarationSyntax.errors.txt b/tests/baselines/reference/jsFileCompilationAmbientVarDeclarationSyntax.errors.txt
index 19bfd5d1c0205..039834ff702af 100644
--- a/tests/baselines/reference/jsFileCompilationAmbientVarDeclarationSyntax.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationAmbientVarDeclarationSyntax.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,1): error TS8009: 'declare' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     declare var v;
     ~~~~~~~
diff --git a/tests/baselines/reference/jsFileCompilationEmitBlockedCorrectly.errors.txt b/tests/baselines/reference/jsFileCompilationEmitBlockedCorrectly.errors.txt
index 0aa9d5733d532..75bcf88b10a13 100644
--- a/tests/baselines/reference/jsFileCompilationEmitBlockedCorrectly.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationEmitBlockedCorrectly.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 error TS5056: Cannot write file 'tests/cases/compiler/a.js' because it would be overwritten by multiple input files.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 !!! error TS5056: Cannot write file 'tests/cases/compiler/a.js' because it would be overwritten by multiple input files.
 ==== tests/cases/compiler/a.ts (0 errors) ====
     class c {
diff --git a/tests/baselines/reference/jsFileCompilationEnumSyntax.errors.txt b/tests/baselines/reference/jsFileCompilationEnumSyntax.errors.txt
index 538dfb38972bc..c6da8931d5e3e 100644
--- a/tests/baselines/reference/jsFileCompilationEnumSyntax.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationEnumSyntax.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,6): error TS8015: 'enum declarations' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     enum E { }
          ~
diff --git a/tests/baselines/reference/jsFileCompilationErrorOnDeclarationsWithJsFileReferenceWithNoOut.errors.txt b/tests/baselines/reference/jsFileCompilationErrorOnDeclarationsWithJsFileReferenceWithNoOut.errors.txt
index 641731936f84a..54e91c5d1961e 100644
--- a/tests/baselines/reference/jsFileCompilationErrorOnDeclarationsWithJsFileReferenceWithNoOut.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationErrorOnDeclarationsWithJsFileReferenceWithNoOut.errors.txt
@@ -1,9 +1,11 @@
 error TS5053: Option 'allowJs' cannot be specified with option 'declaration'.
 error TS5055: Cannot write file 'tests/cases/compiler/c.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5053: Option 'allowJs' cannot be specified with option 'declaration'.
 !!! error TS5055: Cannot write file 'tests/cases/compiler/c.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.ts (0 errors) ====
     class c {
     }
diff --git a/tests/baselines/reference/jsFileCompilationExportAssignmentSyntax.errors.txt b/tests/baselines/reference/jsFileCompilationExportAssignmentSyntax.errors.txt
index f537941c55cf1..babbeea800455 100644
--- a/tests/baselines/reference/jsFileCompilationExportAssignmentSyntax.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationExportAssignmentSyntax.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,1): error TS8003: 'export=' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     export = b;
     ~~~~~~~~~~~
diff --git a/tests/baselines/reference/jsFileCompilationHeritageClauseSyntaxOfClass.errors.txt b/tests/baselines/reference/jsFileCompilationHeritageClauseSyntaxOfClass.errors.txt
index 33b8a45f1aab0..3b30663308fa5 100644
--- a/tests/baselines/reference/jsFileCompilationHeritageClauseSyntaxOfClass.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationHeritageClauseSyntaxOfClass.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,9): error TS8005: 'implements clauses' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     class C implements D { }
             ~~~~~~~~~~~~
diff --git a/tests/baselines/reference/jsFileCompilationImportEqualsSyntax.errors.txt b/tests/baselines/reference/jsFileCompilationImportEqualsSyntax.errors.txt
index b416136703755..a064f53e92fa4 100644
--- a/tests/baselines/reference/jsFileCompilationImportEqualsSyntax.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationImportEqualsSyntax.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,1): error TS8002: 'import ... =' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     import a = b;
     ~~~~~~~~~~~~~
diff --git a/tests/baselines/reference/jsFileCompilationInterfaceSyntax.errors.txt b/tests/baselines/reference/jsFileCompilationInterfaceSyntax.errors.txt
index 17fb8fcb18741..9e53438c732fd 100644
--- a/tests/baselines/reference/jsFileCompilationInterfaceSyntax.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationInterfaceSyntax.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,11): error TS8006: 'interface declarations' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     interface I { }
               ~
diff --git a/tests/baselines/reference/jsFileCompilationModuleSyntax.errors.txt b/tests/baselines/reference/jsFileCompilationModuleSyntax.errors.txt
index 662028c53ed93..6952c0055c0ee 100644
--- a/tests/baselines/reference/jsFileCompilationModuleSyntax.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationModuleSyntax.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,8): error TS8007: 'module declarations' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     module M { }
            ~
diff --git a/tests/baselines/reference/jsFileCompilationNoErrorWithoutDeclarationsWithJsFileReferenceWithNoOut.errors.txt b/tests/baselines/reference/jsFileCompilationNoErrorWithoutDeclarationsWithJsFileReferenceWithNoOut.errors.txt
index f2f4142b99380..888310414f275 100644
--- a/tests/baselines/reference/jsFileCompilationNoErrorWithoutDeclarationsWithJsFileReferenceWithNoOut.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationNoErrorWithoutDeclarationsWithJsFileReferenceWithNoOut.errors.txt
@@ -1,7 +1,9 @@
 error TS5055: Cannot write file 'tests/cases/compiler/c.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/c.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.ts (0 errors) ====
     class c {
     }
diff --git a/tests/baselines/reference/jsFileCompilationOptionalParameter.errors.txt b/tests/baselines/reference/jsFileCompilationOptionalParameter.errors.txt
index 295f827dd2d7c..15bfe2281d96f 100644
--- a/tests/baselines/reference/jsFileCompilationOptionalParameter.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationOptionalParameter.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,13): error TS8009: '?' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     function F(p?) { }
                 ~
diff --git a/tests/baselines/reference/jsFileCompilationPublicMethodSyntaxOfClass.errors.txt b/tests/baselines/reference/jsFileCompilationPublicMethodSyntaxOfClass.errors.txt
index d67c9baea70e5..af95c13620559 100644
--- a/tests/baselines/reference/jsFileCompilationPublicMethodSyntaxOfClass.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationPublicMethodSyntaxOfClass.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(2,5): error TS8009: 'public' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     class C {
         public foo() {
diff --git a/tests/baselines/reference/jsFileCompilationPublicParameterModifier.errors.txt b/tests/baselines/reference/jsFileCompilationPublicParameterModifier.errors.txt
index bc4913f6217b4..9314e1da807aa 100644
--- a/tests/baselines/reference/jsFileCompilationPublicParameterModifier.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationPublicParameterModifier.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,23): error TS8012: 'parameter modifiers' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     class C { constructor(public x) { }}
                           ~~~~~~
diff --git a/tests/baselines/reference/jsFileCompilationReturnTypeSyntaxOfFunction.errors.txt b/tests/baselines/reference/jsFileCompilationReturnTypeSyntaxOfFunction.errors.txt
index 6dad5a294854c..acae950d0816a 100644
--- a/tests/baselines/reference/jsFileCompilationReturnTypeSyntaxOfFunction.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationReturnTypeSyntaxOfFunction.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,15): error TS8010: 'types' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     function F(): number { }
                   ~~~~~~
diff --git a/tests/baselines/reference/jsFileCompilationSyntaxError.errors.txt b/tests/baselines/reference/jsFileCompilationSyntaxError.errors.txt
index d98a1e7e7bbc8..eb4c114d3d074 100644
--- a/tests/baselines/reference/jsFileCompilationSyntaxError.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationSyntaxError.errors.txt
@@ -1,7 +1,9 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (0 errors) ====
     /**
       * @type {number}
diff --git a/tests/baselines/reference/jsFileCompilationTypeAliasSyntax.errors.txt b/tests/baselines/reference/jsFileCompilationTypeAliasSyntax.errors.txt
index 2b5112e1ce2ed..74978eddf8ce1 100644
--- a/tests/baselines/reference/jsFileCompilationTypeAliasSyntax.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationTypeAliasSyntax.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,6): error TS8008: 'type aliases' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     type a = b;
          ~
diff --git a/tests/baselines/reference/jsFileCompilationTypeArgumentSyntaxOfCall.errors.txt b/tests/baselines/reference/jsFileCompilationTypeArgumentSyntaxOfCall.errors.txt
index 8ac59196ed960..f53ec55d2b1e0 100644
--- a/tests/baselines/reference/jsFileCompilationTypeArgumentSyntaxOfCall.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationTypeArgumentSyntaxOfCall.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,5): error TS8011: 'type arguments' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     Foo<number>();
         ~~~~~~
diff --git a/tests/baselines/reference/jsFileCompilationTypeAssertions.errors.txt b/tests/baselines/reference/jsFileCompilationTypeAssertions.errors.txt
index 662eea4d4050c..be1e6d3243699 100644
--- a/tests/baselines/reference/jsFileCompilationTypeAssertions.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationTypeAssertions.errors.txt
@@ -1,9 +1,11 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,10): error TS17008: JSX element 'string' has no corresponding closing tag.
 tests/cases/compiler/a.js(1,27): error TS1005: '</' expected.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (2 errors) ====
     var v = <string>undefined;
              ~~~~~~
diff --git a/tests/baselines/reference/jsFileCompilationTypeOfParameter.errors.txt b/tests/baselines/reference/jsFileCompilationTypeOfParameter.errors.txt
index 680b32a64f1ad..811c0793ffe15 100644
--- a/tests/baselines/reference/jsFileCompilationTypeOfParameter.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationTypeOfParameter.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,15): error TS8010: 'types' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     function F(a: number) { }
                   ~~~~~~
diff --git a/tests/baselines/reference/jsFileCompilationTypeParameterSyntaxOfClass.errors.txt b/tests/baselines/reference/jsFileCompilationTypeParameterSyntaxOfClass.errors.txt
index 161c832ffd5d4..0fe902aa661cb 100644
--- a/tests/baselines/reference/jsFileCompilationTypeParameterSyntaxOfClass.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationTypeParameterSyntaxOfClass.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,9): error TS8004: 'type parameter declarations' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     class C<T> { }
             ~
diff --git a/tests/baselines/reference/jsFileCompilationTypeParameterSyntaxOfFunction.errors.txt b/tests/baselines/reference/jsFileCompilationTypeParameterSyntaxOfFunction.errors.txt
index d7626f68564cf..bfc4c7be26a4d 100644
--- a/tests/baselines/reference/jsFileCompilationTypeParameterSyntaxOfFunction.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationTypeParameterSyntaxOfFunction.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,12): error TS8004: 'type parameter declarations' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     function F<T>() { }
                ~
diff --git a/tests/baselines/reference/jsFileCompilationTypeSyntaxOfVar.errors.txt b/tests/baselines/reference/jsFileCompilationTypeSyntaxOfVar.errors.txt
index 2c6ac3771bef8..653337517800b 100644
--- a/tests/baselines/reference/jsFileCompilationTypeSyntaxOfVar.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationTypeSyntaxOfVar.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 tests/cases/compiler/a.js(1,8): error TS8010: 'types' can only be used in a .ts file.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.js (1 errors) ====
     var v: () => number;
            ~~~~~~~~~~~~
diff --git a/tests/baselines/reference/jsFileCompilationWithDeclarationEmitPathSameAsInput.errors.txt b/tests/baselines/reference/jsFileCompilationWithDeclarationEmitPathSameAsInput.errors.txt
index 9e9c2adb0efa2..4170e818fd76b 100644
--- a/tests/baselines/reference/jsFileCompilationWithDeclarationEmitPathSameAsInput.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationWithDeclarationEmitPathSameAsInput.errors.txt
@@ -1,7 +1,9 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.d.ts' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.d.ts' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.ts (0 errors) ====
     class c {
     }
diff --git a/tests/baselines/reference/jsFileCompilationWithJsEmitPathSameAsInput.errors.txt b/tests/baselines/reference/jsFileCompilationWithJsEmitPathSameAsInput.errors.txt
index 4cc2cc2ab4547..8004efd02eff4 100644
--- a/tests/baselines/reference/jsFileCompilationWithJsEmitPathSameAsInput.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationWithJsEmitPathSameAsInput.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 error TS5056: Cannot write file 'tests/cases/compiler/a.js' because it would be overwritten by multiple input files.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 !!! error TS5056: Cannot write file 'tests/cases/compiler/a.js' because it would be overwritten by multiple input files.
 ==== tests/cases/compiler/a.ts (0 errors) ====
     class c {
diff --git a/tests/baselines/reference/jsFileCompilationWithMapFileAsJs.errors.txt b/tests/baselines/reference/jsFileCompilationWithMapFileAsJs.errors.txt
index 06186b9f0b2fc..069c562f29bf8 100644
--- a/tests/baselines/reference/jsFileCompilationWithMapFileAsJs.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationWithMapFileAsJs.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 error TS6054: File 'tests/cases/compiler/b.js.map' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx'.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 !!! error TS6054: File 'tests/cases/compiler/b.js.map' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx'.
 ==== tests/cases/compiler/a.ts (0 errors) ====
     
diff --git a/tests/baselines/reference/jsFileCompilationWithMapFileAsJsWithInlineSourceMap.errors.txt b/tests/baselines/reference/jsFileCompilationWithMapFileAsJsWithInlineSourceMap.errors.txt
index 06186b9f0b2fc..069c562f29bf8 100644
--- a/tests/baselines/reference/jsFileCompilationWithMapFileAsJsWithInlineSourceMap.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationWithMapFileAsJsWithInlineSourceMap.errors.txt
@@ -1,8 +1,10 @@
 error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 error TS6054: File 'tests/cases/compiler/b.js.map' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx'.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 !!! error TS6054: File 'tests/cases/compiler/b.js.map' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx'.
 ==== tests/cases/compiler/a.ts (0 errors) ====
     
diff --git a/tests/baselines/reference/jsFileCompilationWithOutDeclarationFileNameSameAsInputJsFile.errors.txt b/tests/baselines/reference/jsFileCompilationWithOutDeclarationFileNameSameAsInputJsFile.errors.txt
index 10c7b8c90ddad..0a4f0cdf1a45b 100644
--- a/tests/baselines/reference/jsFileCompilationWithOutDeclarationFileNameSameAsInputJsFile.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationWithOutDeclarationFileNameSameAsInputJsFile.errors.txt
@@ -1,7 +1,9 @@
 error TS5055: Cannot write file 'tests/cases/compiler/b.d.ts' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/b.d.ts' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.ts (0 errors) ====
     class c {
     }
diff --git a/tests/baselines/reference/jsFileCompilationWithOutFileNameSameAsInputJsFile.errors.txt b/tests/baselines/reference/jsFileCompilationWithOutFileNameSameAsInputJsFile.errors.txt
index 0f6852b21a0a2..3f72a8113ef2c 100644
--- a/tests/baselines/reference/jsFileCompilationWithOutFileNameSameAsInputJsFile.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationWithOutFileNameSameAsInputJsFile.errors.txt
@@ -1,7 +1,9 @@
 error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.ts (0 errors) ====
     class c {
     }
diff --git a/tests/baselines/reference/jsFileCompilationWithoutOut.errors.txt b/tests/baselines/reference/jsFileCompilationWithoutOut.errors.txt
index 0f6852b21a0a2..3f72a8113ef2c 100644
--- a/tests/baselines/reference/jsFileCompilationWithoutOut.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationWithoutOut.errors.txt
@@ -1,7 +1,9 @@
 error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== tests/cases/compiler/a.ts (0 errors) ====
     class c {
     }
diff --git a/tests/baselines/reference/project/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs/amd/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs.errors.txt b/tests/baselines/reference/project/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs/amd/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs.errors.txt
index ac25edc1bd565..668f037a03b4d 100644
--- a/tests/baselines/reference/project/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs/amd/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs.errors.txt
+++ b/tests/baselines/reference/project/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs/amd/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs.errors.txt
@@ -1,9 +1,11 @@
 error TS5053: Option 'allowJs' cannot be specified with option 'declaration'.
 error TS5055: Cannot write file 'SameNameDTsNotSpecifiedWithAllowJs/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5053: Option 'allowJs' cannot be specified with option 'declaration'.
 !!! error TS5055: Cannot write file 'SameNameDTsNotSpecifiedWithAllowJs/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== SameNameDTsNotSpecifiedWithAllowJs/a.d.ts (0 errors) ====
     declare var a: number;
 ==== SameNameDTsNotSpecifiedWithAllowJs/a.js (0 errors) ====
diff --git a/tests/baselines/reference/project/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs/node/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs.errors.txt b/tests/baselines/reference/project/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs/node/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs.errors.txt
index ac25edc1bd565..668f037a03b4d 100644
--- a/tests/baselines/reference/project/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs/node/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs.errors.txt
+++ b/tests/baselines/reference/project/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs/node/jsFileCompilationSameNameDtsNotSpecifiedWithAllowJs.errors.txt
@@ -1,9 +1,11 @@
 error TS5053: Option 'allowJs' cannot be specified with option 'declaration'.
 error TS5055: Cannot write file 'SameNameDTsNotSpecifiedWithAllowJs/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 
 
 !!! error TS5053: Option 'allowJs' cannot be specified with option 'declaration'.
 !!! error TS5055: Cannot write file 'SameNameDTsNotSpecifiedWithAllowJs/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
 ==== SameNameDTsNotSpecifiedWithAllowJs/a.d.ts (0 errors) ====
     declare var a: number;
 ==== SameNameDTsNotSpecifiedWithAllowJs/a.js (0 errors) ====

From 71f3157a35cacd404371d6020929a1299d959f15 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 4 Nov 2016 09:03:03 -0700
Subject: [PATCH 170/224] Address PR comments

1. Remove extra line in __rest shim.
2. Improve __rest vs __assign check for destructuring assignment.
---
 src/compiler/binder.ts  | 12 ++++++++++--
 src/compiler/emitter.ts |  1 -
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index a4d9a5a30ed02..7aa27e520d3e2 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -1935,10 +1935,18 @@ namespace ts {
                 case SyntaxKind.SpreadElementExpression:
                 case SyntaxKind.JsxSpreadAttribute:
                     let root = container;
-                    while (root && root.kind !== SyntaxKind.BinaryExpression) {
+                    let hasRest = false;
+                    while (root.parent) {
+                        if (root.kind === SyntaxKind.ObjectLiteralExpression &&
+                            root.parent.kind === SyntaxKind.BinaryExpression &&
+                            (root.parent as BinaryExpression).operatorToken.kind === SyntaxKind.EqualsToken &&
+                            (root.parent as BinaryExpression).left === root) {
+                            hasRest = true;
+                            break;
+                        }
                         root = root.parent;
                     }
-                    emitFlags |= root && isDestructuringAssignment(root) ? NodeFlags.HasRestAttribute : NodeFlags.HasSpreadAttribute;
+                    emitFlags |= hasRest ? NodeFlags.HasRestAttribute : NodeFlags.HasSpreadAttribute;
                     return;
 
                 case SyntaxKind.CallSignature:
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index c89fa1f155043..9885ea9c79179 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -45,7 +45,6 @@ var __assign = (this && this.__assign) || Object.assign || function(t) {
         const restHelper = `
 var __rest = (this && this.__rest) || function (s, e) {
     var t = {};
-
     for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
         t[p] = s[p];
     return t;

From cc342d12e7c63e4abb2725ee81d747672cefae46 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 4 Nov 2016 11:06:56 -0700
Subject: [PATCH 171/224] Move convertForOf to factory for esnext and es2015

Saves a lot of duplicated code
---
 src/compiler/factory.ts             | 190 ++++++++++++++++++++++++++++
 src/compiler/transformers/es2015.ts | 166 +-----------------------
 src/compiler/transformers/esnext.ts |  87 +------------
 3 files changed, 192 insertions(+), 251 deletions(-)

diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index c7fe7d7057499..7f758f7079479 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -3055,4 +3055,194 @@ namespace ts {
     function tryGetModuleNameFromDeclaration(declaration: ImportEqualsDeclaration | ImportDeclaration | ExportDeclaration, host: EmitHost, resolver: EmitResolver, compilerOptions: CompilerOptions) {
         return tryGetModuleNameFromFile(resolver.getExternalModuleFileFromDeclaration(declaration), host, compilerOptions);
     }
+
+    export function convertForOf(node: ForOfStatement, convertedLoopBodyStatements: Statement[],
+                                 visitor: (node: Node) => VisitResult<Node>,
+                                 enableSubstitutionsForBlockScopedBindings: () => void,
+                                 context: TransformationContext,
+                                 convertObjectRest?: boolean): ForStatement | ForOfStatement {
+        // The following ES6 code:
+        //
+        //    for (let v of expr) { }
+        //
+        // should be emitted as
+        //
+        //    for (var _i = 0, _a = expr; _i < _a.length; _i++) {
+        //        var v = _a[_i];
+        //    }
+        //
+        // where _a and _i are temps emitted to capture the RHS and the counter,
+        // respectively.
+        // When the left hand side is an expression instead of a let declaration,
+        // the "let v" is not emitted.
+        // When the left hand side is a let/const, the v is renamed if there is
+        // another v in scope.
+        // Note that all assignments to the LHS are emitted in the body, including
+        // all destructuring.
+        // Note also that because an extra statement is needed to assign to the LHS,
+        // for-of bodies are always emitted as blocks.
+
+        const expression = visitNode(node.expression, visitor, isExpression);
+        const initializer = node.initializer;
+        const statements: Statement[] = [];
+
+        // In the case where the user wrote an identifier as the RHS, like this:
+        //
+        //     for (let v of arr) { }
+        //
+        // we don't want to emit a temporary variable for the RHS, just use it directly.
+        const counter = convertObjectRest ? undefined : createLoopVariable();
+        const rhsReference = expression.kind === SyntaxKind.Identifier
+            ? createUniqueName((<Identifier>expression).text)
+            : createTempVariable(/*recordTempVariable*/ undefined);
+        const elementAccess = convertObjectRest ? rhsReference : createElementAccess(rhsReference, counter);
+
+        // Initialize LHS
+        // var v = _a[_i];
+        if (isVariableDeclarationList(initializer)) {
+            if (initializer.flags & NodeFlags.BlockScoped) {
+                enableSubstitutionsForBlockScopedBindings();
+            }
+
+            const firstOriginalDeclaration = firstOrUndefined(initializer.declarations);
+            if (firstOriginalDeclaration && isBindingPattern(firstOriginalDeclaration.name)) {
+                // This works whether the declaration is a var, let, or const.
+                // It will use rhsIterationValue _a[_i] as the initializer.
+                const declarations = flattenVariableDestructuring(
+                    firstOriginalDeclaration,
+                    elementAccess,
+                    visitor,
+                    /*recordTempVariable*/ undefined,
+                    convertObjectRest
+                );
+
+                const declarationList = createVariableDeclarationList(declarations, /*location*/ initializer);
+                setOriginalNode(declarationList, initializer);
+
+                // Adjust the source map range for the first declaration to align with the old
+                // emitter.
+                const firstDeclaration = declarations[0];
+                const lastDeclaration = lastOrUndefined(declarations);
+                setSourceMapRange(declarationList, createRange(firstDeclaration.pos, lastDeclaration.end));
+
+                statements.push(
+                    createVariableStatement(
+                        /*modifiers*/ undefined,
+                        declarationList
+                    )
+                );
+            }
+            else {
+                // The following call does not include the initializer, so we have
+                // to emit it separately.
+                statements.push(
+                    createVariableStatement(
+                        /*modifiers*/ undefined,
+                        setOriginalNode(
+                            createVariableDeclarationList([
+                                createVariableDeclaration(
+                                    firstOriginalDeclaration ? firstOriginalDeclaration.name : createTempVariable(/*recordTempVariable*/ undefined),
+                                    /*type*/ undefined,
+                                    createElementAccess(rhsReference, counter)
+                                )
+                            ], /*location*/ moveRangePos(initializer, -1)),
+                            initializer
+                        ),
+                        /*location*/ moveRangeEnd(initializer, -1)
+                    )
+                );
+            }
+        }
+        else {
+            // Initializer is an expression. Emit the expression in the body, so that it's
+            // evaluated on every iteration.
+            const assignment = createAssignment(initializer, elementAccess);
+            if (isDestructuringAssignment(assignment)) {
+                // This is a destructuring pattern, so we flatten the destructuring instead.
+                statements.push(
+                    createStatement(
+                        flattenDestructuringAssignment(
+                            context,
+                            assignment,
+                            /*needsValue*/ false,
+                            context.hoistVariableDeclaration,
+                            visitor,
+                            convertObjectRest
+                        )
+                    )
+                );
+            }
+            else {
+                // Currently there is not way to check that assignment is binary expression of destructing assignment
+                // so we have to cast never type to binaryExpression
+                (<BinaryExpression>assignment).end = initializer.end;
+                statements.push(createStatement(assignment, /*location*/ moveRangeEnd(initializer, -1)));
+            }
+        }
+
+        let bodyLocation: TextRange;
+        let statementsLocation: TextRange;
+        if (convertedLoopBodyStatements) {
+            addRange(statements, convertedLoopBodyStatements);
+        }
+        else {
+            const statement = visitNode(node.statement, visitor, isStatement);
+            if (isBlock(statement)) {
+                addRange(statements, statement.statements);
+                bodyLocation = statement;
+                statementsLocation = statement.statements;
+            }
+            else {
+                statements.push(statement);
+            }
+        }
+
+        // The old emitter does not emit source maps for the expression
+        setEmitFlags(expression, EmitFlags.NoSourceMap | getEmitFlags(expression));
+
+        // The old emitter does not emit source maps for the block.
+        // We add the location to preserve comments.
+        const body = createBlock(
+            createNodeArray(statements, /*location*/ statementsLocation),
+            /*location*/ bodyLocation
+        );
+
+        setEmitFlags(body, EmitFlags.NoSourceMap | EmitFlags.NoTokenSourceMaps);
+
+        let forStatement: ForStatement | ForOfStatement;
+        if(convertObjectRest) {
+
+            forStatement = createForOf(
+                createVariableDeclarationList([
+                    createVariableDeclaration(rhsReference, /*type*/ undefined, /*initializer*/ undefined, /*location*/ node.expression)
+                ], /*location*/ node.expression),
+                node.expression,
+                body,
+                /*location*/ node
+            );
+        }
+        else {
+            forStatement = createFor(
+                setEmitFlags(
+                    createVariableDeclarationList([
+                        createVariableDeclaration(counter, /*type*/ undefined, createLiteral(0), /*location*/ moveRangePos(node.expression, -1)),
+                        createVariableDeclaration(rhsReference, /*type*/ undefined, expression, /*location*/ node.expression)
+                    ], /*location*/ node.expression),
+                    EmitFlags.NoHoisting
+                ),
+                createLessThan(
+                    counter,
+                    createPropertyAccess(rhsReference, "length"),
+                    /*location*/ node.expression
+                ),
+                createPostfixIncrement(counter, /*location*/ node.expression),
+                body,
+                /*location*/ node
+            );
+        }
+
+        // Disable trailing source maps for the OpenParenToken to align source map emit with the old emitter.
+        setEmitFlags(forStatement, EmitFlags.NoTokenTrailingSourceMaps);
+        return forStatement;
+    }
 }
diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
index e262b413b4c72..76ea6b2ddd0b8 100644
--- a/src/compiler/transformers/es2015.ts
+++ b/src/compiler/transformers/es2015.ts
@@ -1926,171 +1926,7 @@ namespace ts {
         }
 
         function convertForOfToFor(node: ForOfStatement, convertedLoopBodyStatements: Statement[]): ForStatement {
-            // The following ES6 code:
-            //
-            //    for (let v of expr) { }
-            //
-            // should be emitted as
-            //
-            //    for (var _i = 0, _a = expr; _i < _a.length; _i++) {
-            //        var v = _a[_i];
-            //    }
-            //
-            // where _a and _i are temps emitted to capture the RHS and the counter,
-            // respectively.
-            // When the left hand side is an expression instead of a let declaration,
-            // the "let v" is not emitted.
-            // When the left hand side is a let/const, the v is renamed if there is
-            // another v in scope.
-            // Note that all assignments to the LHS are emitted in the body, including
-            // all destructuring.
-            // Note also that because an extra statement is needed to assign to the LHS,
-            // for-of bodies are always emitted as blocks.
-
-            const expression = visitNode(node.expression, visitor, isExpression);
-            const initializer = node.initializer;
-            const statements: Statement[] = [];
-
-            // In the case where the user wrote an identifier as the RHS, like this:
-            //
-            //     for (let v of arr) { }
-            //
-            // we don't want to emit a temporary variable for the RHS, just use it directly.
-            const counter = createLoopVariable();
-            const rhsReference = expression.kind === SyntaxKind.Identifier
-                ? createUniqueName((<Identifier>expression).text)
-                : createTempVariable(/*recordTempVariable*/ undefined);
-
-            // Initialize LHS
-            // var v = _a[_i];
-            if (isVariableDeclarationList(initializer)) {
-                if (initializer.flags & NodeFlags.BlockScoped) {
-                    enableSubstitutionsForBlockScopedBindings();
-                }
-
-                const firstOriginalDeclaration = firstOrUndefined(initializer.declarations);
-                if (firstOriginalDeclaration && isBindingPattern(firstOriginalDeclaration.name)) {
-                    // This works whether the declaration is a var, let, or const.
-                    // It will use rhsIterationValue _a[_i] as the initializer.
-                    const declarations = flattenVariableDestructuring(
-                        firstOriginalDeclaration,
-                        createElementAccess(rhsReference, counter),
-                        visitor
-                    );
-
-                    const declarationList = createVariableDeclarationList(declarations, /*location*/ initializer);
-                    setOriginalNode(declarationList, initializer);
-
-                    // Adjust the source map range for the first declaration to align with the old
-                    // emitter.
-                    const firstDeclaration = declarations[0];
-                    const lastDeclaration = lastOrUndefined(declarations);
-                    setSourceMapRange(declarationList, createRange(firstDeclaration.pos, lastDeclaration.end));
-
-                    statements.push(
-                        createVariableStatement(
-                            /*modifiers*/ undefined,
-                            declarationList
-                        )
-                    );
-                }
-                else {
-                    // The following call does not include the initializer, so we have
-                    // to emit it separately.
-                    statements.push(
-                        createVariableStatement(
-                            /*modifiers*/ undefined,
-                            setOriginalNode(
-                                createVariableDeclarationList([
-                                    createVariableDeclaration(
-                                        firstOriginalDeclaration ? firstOriginalDeclaration.name : createTempVariable(/*recordTempVariable*/ undefined),
-                                        /*type*/ undefined,
-                                        createElementAccess(rhsReference, counter)
-                                    )
-                                ], /*location*/ moveRangePos(initializer, -1)),
-                                initializer
-                            ),
-                            /*location*/ moveRangeEnd(initializer, -1)
-                        )
-                    );
-                }
-            }
-            else {
-                // Initializer is an expression. Emit the expression in the body, so that it's
-                // evaluated on every iteration.
-                const assignment = createAssignment(initializer, createElementAccess(rhsReference, counter));
-                if (isDestructuringAssignment(assignment)) {
-                    // This is a destructuring pattern, so we flatten the destructuring instead.
-                    statements.push(
-                        createStatement(
-                            flattenDestructuringAssignment(
-                                context,
-                                assignment,
-                                /*needsValue*/ false,
-                                hoistVariableDeclaration,
-                                visitor
-                            )
-                        )
-                    );
-                }
-                else {
-                    // Currently there is not way to check that assignment is binary expression of destructing assignment
-                    // so we have to cast never type to binaryExpression
-                    (<BinaryExpression>assignment).end = initializer.end;
-                    statements.push(createStatement(assignment, /*location*/ moveRangeEnd(initializer, -1)));
-                }
-            }
-
-            let bodyLocation: TextRange;
-            let statementsLocation: TextRange;
-            if (convertedLoopBodyStatements) {
-                addRange(statements, convertedLoopBodyStatements);
-            }
-            else {
-                const statement = visitNode(node.statement, visitor, isStatement);
-                if (isBlock(statement)) {
-                    addRange(statements, statement.statements);
-                    bodyLocation = statement;
-                    statementsLocation = statement.statements;
-                }
-                else {
-                    statements.push(statement);
-                }
-            }
-
-            // The old emitter does not emit source maps for the expression
-            setEmitFlags(expression, EmitFlags.NoSourceMap | getEmitFlags(expression));
-
-            // The old emitter does not emit source maps for the block.
-            // We add the location to preserve comments.
-            const body = createBlock(
-                createNodeArray(statements, /*location*/ statementsLocation),
-                /*location*/ bodyLocation
-            );
-
-            setEmitFlags(body, EmitFlags.NoSourceMap | EmitFlags.NoTokenSourceMaps);
-
-            const forStatement = createFor(
-                setEmitFlags(
-                    createVariableDeclarationList([
-                        createVariableDeclaration(counter, /*type*/ undefined, createLiteral(0), /*location*/ moveRangePos(node.expression, -1)),
-                        createVariableDeclaration(rhsReference, /*type*/ undefined, expression, /*location*/ node.expression)
-                    ], /*location*/ node.expression),
-                    EmitFlags.NoHoisting
-                ),
-                createLessThan(
-                    counter,
-                    createPropertyAccess(rhsReference, "length"),
-                    /*location*/ node.expression
-                ),
-                createPostfixIncrement(counter, /*location*/ node.expression),
-                body,
-                /*location*/ node
-            );
-
-            // Disable trailing source maps for the OpenParenToken to align source map emit with the old emitter.
-            setEmitFlags(forStatement, EmitFlags.NoTokenTrailingSourceMaps);
-            return forStatement;
+            return <ForStatement>convertForOf(node, convertedLoopBodyStatements, visitor, enableSubstitutionsForBlockScopedBindings, context, /*transformRest*/ false);
         }
 
         /**
diff --git a/src/compiler/transformers/esnext.ts b/src/compiler/transformers/esnext.ts
index a85098f03b6d9..26864a123ea33 100644
--- a/src/compiler/transformers/esnext.ts
+++ b/src/compiler/transformers/esnext.ts
@@ -162,92 +162,7 @@ namespace ts {
                 return visitEachChild(node, visitor, context);
             }
 
-            const expression = visitNode(node.expression, visitor, isExpression);
-            const statements: Statement[] = [];
-            const rhsReference = createTempVariable(/*recordTempVariable*/ undefined);
-
-            // var { x, y } = _a, rest = __rest(_a, ["x", "y"]);
-            if (isVariableDeclarationList(initializer)) {
-                // This works whether the declaration is a var, let, or const.
-                // It will use rhsReference _a as the initializer.
-                const declarations = flattenVariableDestructuring(
-                    initializer.declarations[0],
-                    rhsReference,
-                    visitor,
-                    /*recordTempVariable*/ undefined,
-                    /*transformRest*/ true,
-                );
-
-                const declarationList = createVariableDeclarationList(declarations, /*location*/ initializer);
-                setOriginalNode(declarationList, initializer);
-
-                // Adjust the source map range for the first declaration to align with the old
-                // emitter.
-                const firstDeclaration = declarations[0];
-                const lastDeclaration = lastOrUndefined(declarations);
-                setSourceMapRange(declarationList, createRange(firstDeclaration.pos, lastDeclaration.end));
-
-                statements.push(
-                    createVariableStatement(
-                        /*modifiers*/ undefined,
-                        declarationList
-                    )
-                );
-            }
-            else {
-                // Initializer is an object literal destructuring assignment.
-                // Emit the flattened assignments from the object literal expression in the body
-                const assignment = createAssignment(initializer, rhsReference);
-                statements.push(
-                    createStatement(
-                        flattenDestructuringAssignment(
-                            context,
-                            assignment,
-                            /*needsValue*/ false,
-                            hoistVariableDeclaration,
-                            visitor,
-                            /*transformRest*/ true
-                        )
-                    )
-                );
-            }
-
-            let bodyLocation: TextRange;
-            let statementsLocation: TextRange;
-            const statement = visitNode(node.statement, visitor, isStatement);
-            if (isBlock(statement)) {
-                addRange(statements, statement.statements);
-                bodyLocation = statement;
-                statementsLocation = statement.statements;
-            }
-            else {
-                statements.push(statement);
-            }
-
-            // The old emitter does not emit source maps for the expression
-            setEmitFlags(expression, EmitFlags.NoSourceMap | getEmitFlags(expression));
-
-            // The old emitter does not emit source maps for the block.
-            // We add the location to preserve comments.
-            const body = createBlock(
-                createNodeArray(statements, /*location*/ statementsLocation),
-                /*location*/ bodyLocation
-            );
-
-            setEmitFlags(body, EmitFlags.NoSourceMap | EmitFlags.NoTokenSourceMaps);
-
-            const forStatement = createForOf(
-                createVariableDeclarationList([
-                    createVariableDeclaration(rhsReference, /*type*/ undefined, /*initializer*/ undefined, /*location*/ node.expression)
-                ], /*location*/ node.expression),
-                node.expression,
-                body,
-                /*location*/ node
-            );
-
-            // Disable trailing source maps for the OpenParenToken to align source map emit with the old emitter.
-            setEmitFlags(forStatement, EmitFlags.NoTokenTrailingSourceMaps);
-            return forStatement;
+            return convertForOf(node, undefined, visitor, noop, context, /*transformRest*/ true);
         }
 
         function isRestBindingPattern(initializer: ForInitializer) {

From 4337369ed4996856925c59fc43ccde201efaf316 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 4 Nov 2016 11:07:18 -0700
Subject: [PATCH 172/224] Update improved baselines

---
 tests/baselines/reference/objectRestForOf.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tests/baselines/reference/objectRestForOf.js b/tests/baselines/reference/objectRestForOf.js
index 0a6e2dc40ed34..26ebd8f8229c5 100644
--- a/tests/baselines/reference/objectRestForOf.js
+++ b/tests/baselines/reference/objectRestForOf.js
@@ -30,14 +30,14 @@ var __rest = (this && this.__rest) || function (s, e) {
     return t;
 };
 let array;
-for (var _a of array) {
-    var { x } = _a, restOf = __rest(_a, ["x"]);
+for (var array_1 of array) {
+    var { x } = array_1, restOf = __rest(array_1, ["x"]);
     [x, restOf];
 }
 let xx;
 let rrestOff;
-for (var _b of array) {
-    ({ x: xx } = _b, rrestOff = __rest(_b, ["x"]));
+for (var array_2 of array) {
+    ({ x: xx } = array_2, rrestOff = __rest(array_2, ["x"]));
     [xx, rrestOff];
 }
 for (const norest of array.map(a => (__assign({}, a, { x: 'a string' })))) {

From 4c365bd76a6357f33a5f3f5345a2ed276d22149a Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 4 Nov 2016 13:56:28 -0700
Subject: [PATCH 173/224] Move transformFunctionBody to factory

It is shared by es2015 and esNext transformers.

This commit just adds a convertObjectRest flag to be passed on to
flattenDestructuring functions, as well as adding necessary parameters
to use the code outside a transformer.
---
 src/compiler/factory.ts             | 345 ++++++++++++++++++++++++++++
 src/compiler/transformers/es2015.ts | 338 +--------------------------
 src/compiler/transformers/esnext.ts | 183 ++-------------
 3 files changed, 367 insertions(+), 499 deletions(-)

diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 7f758f7079479..605725b89cf57 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -3056,6 +3056,351 @@ namespace ts {
         return tryGetModuleNameFromFile(resolver.getExternalModuleFileFromDeclaration(declaration), host, compilerOptions);
     }
 
+    /**
+     * Transforms the body of a function-like node.
+     *
+     * @param node A function-like node.
+     */
+    export function transformFunctionBody(node: FunctionLikeDeclaration,
+                                          visitor: (node: Node) => VisitResult<Node>,
+                                          currentSourceFile: SourceFile,
+                                          context: TransformationContext,
+                                          enableSubstitutionsForCapturedThis: () => void,
+                                          convertObjectRest?: boolean) {
+        let multiLine = false; // indicates whether the block *must* be emitted as multiple lines
+        let singleLine = false; // indicates whether the block *may* be emitted as a single line
+        let statementsLocation: TextRange;
+        let closeBraceLocation: TextRange;
+
+        const statements: Statement[] = [];
+        const body = node.body;
+        let statementOffset: number;
+
+        context.startLexicalEnvironment();
+        if (isBlock(body)) {
+            // ensureUseStrict is false because no new prologue-directive should be added.
+            // addPrologueDirectives will simply put already-existing directives at the beginning of the target statement-array
+            statementOffset = addPrologueDirectives(statements, body.statements, /*ensureUseStrict*/ false, visitor);
+        }
+
+        addCaptureThisForNodeIfNeeded(statements, node, enableSubstitutionsForCapturedThis);
+        addDefaultValueAssignmentsIfNeeded(statements, node, visitor, convertObjectRest);
+        addRestParameterIfNeeded(statements, node, /*inConstructorWithSynthesizedSuper*/ false);
+
+        // If we added any generated statements, this must be a multi-line block.
+        if (!multiLine && statements.length > 0) {
+            multiLine = true;
+        }
+
+        if (isBlock(body)) {
+            statementsLocation = body.statements;
+            addRange(statements, visitNodes(body.statements, visitor, isStatement, statementOffset));
+
+            // If the original body was a multi-line block, this must be a multi-line block.
+            if (!multiLine && body.multiLine) {
+                multiLine = true;
+            }
+        }
+        else {
+            Debug.assert(node.kind === SyntaxKind.ArrowFunction);
+
+            // To align with the old emitter, we use a synthetic end position on the location
+            // for the statement list we synthesize when we down-level an arrow function with
+            // an expression function body. This prevents both comments and source maps from
+            // being emitted for the end position only.
+            statementsLocation = moveRangeEnd(body, -1);
+
+            const equalsGreaterThanToken = (<ArrowFunction>node).equalsGreaterThanToken;
+            if (!nodeIsSynthesized(equalsGreaterThanToken) && !nodeIsSynthesized(body)) {
+                if (rangeEndIsOnSameLineAsRangeStart(equalsGreaterThanToken, body, currentSourceFile)) {
+                    singleLine = true;
+                }
+                else {
+                    multiLine = true;
+                }
+            }
+
+            const expression = visitNode(body, visitor, isExpression);
+            const returnStatement = createReturn(expression, /*location*/ body);
+            setEmitFlags(returnStatement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoTrailingSourceMap | EmitFlags.NoTrailingComments);
+            statements.push(returnStatement);
+
+            // To align with the source map emit for the old emitter, we set a custom
+            // source map location for the close brace.
+            closeBraceLocation = body;
+        }
+
+        const lexicalEnvironment = context.endLexicalEnvironment();
+        addRange(statements, lexicalEnvironment);
+
+        // If we added any final generated statements, this must be a multi-line block
+        if (!multiLine && lexicalEnvironment && lexicalEnvironment.length) {
+            multiLine = true;
+        }
+
+        const block = createBlock(createNodeArray(statements, statementsLocation), node.body, multiLine);
+        if (!multiLine && singleLine) {
+            setEmitFlags(block, EmitFlags.SingleLine);
+        }
+
+        if (closeBraceLocation) {
+            setTokenSourceMapRange(block, SyntaxKind.CloseBraceToken, closeBraceLocation);
+        }
+
+        setOriginalNode(block, node.body);
+        return block;
+    }
+
+    /**
+     * Adds a statement to capture the `this` of a function declaration if it is needed.
+     *
+     * @param statements The statements for the new function body.
+     * @param node A node.
+     */
+    export function addCaptureThisForNodeIfNeeded(statements: Statement[], node: Node, enableSubstitutionsForCapturedThis: () => void): void {
+        if (node.transformFlags & TransformFlags.ContainsCapturedLexicalThis && node.kind !== SyntaxKind.ArrowFunction) {
+            captureThisForNode(statements, node, createThis(), enableSubstitutionsForCapturedThis);
+        }
+    }
+
+    export function captureThisForNode(statements: Statement[], node: Node, initializer: Expression | undefined, enableSubstitutionsForCapturedThis?: () => void, originalStatement?: Statement): void {
+        enableSubstitutionsForCapturedThis();
+        const captureThisStatement = createVariableStatement(
+            /*modifiers*/ undefined,
+            createVariableDeclarationList([
+                createVariableDeclaration(
+                    "_this",
+                    /*type*/ undefined,
+                    initializer
+                )
+            ]),
+            originalStatement
+        );
+
+        setEmitFlags(captureThisStatement, EmitFlags.NoComments | EmitFlags.CustomPrologue);
+        setSourceMapRange(captureThisStatement, node);
+        statements.push(captureThisStatement);
+    }
+
+    /**
+     * Gets a value indicating whether we need to add default value assignments for a
+     * function-like node.
+     *
+     * @param node A function-like node.
+     */
+    function shouldAddDefaultValueAssignments(node: FunctionLikeDeclaration): boolean {
+        return (node.transformFlags & TransformFlags.ContainsDefaultValueAssignments) !== 0;
+    }
+
+    /**
+     * Adds statements to the body of a function-like node if it contains parameters with
+     * binding patterns or initializers.
+     *
+     * @param statements The statements for the new function body.
+     * @param node A function-like node.
+     */
+    export function addDefaultValueAssignmentsIfNeeded(statements: Statement[],
+                                                       node: FunctionLikeDeclaration,
+                                                       visitor: (node: Node) => VisitResult<Node>,
+                                                       convertObjectRest: boolean): void {
+        if (!shouldAddDefaultValueAssignments(node)) {
+            return;
+        }
+
+        for (const parameter of node.parameters) {
+            const { name, initializer, dotDotDotToken } = parameter;
+
+            // A rest parameter cannot have a binding pattern or an initializer,
+            // so let's just ignore it.
+            if (dotDotDotToken) {
+                continue;
+            }
+
+            if (isBindingPattern(name)) {
+                addDefaultValueAssignmentForBindingPattern(statements, parameter, name, initializer, visitor, convertObjectRest);
+            }
+            else if (initializer) {
+                addDefaultValueAssignmentForInitializer(statements, parameter, name, initializer, visitor);
+            }
+        }
+    }
+
+    /**
+     * Adds statements to the body of a function-like node for parameters with binding patterns
+     *
+     * @param statements The statements for the new function body.
+     * @param parameter The parameter for the function.
+     * @param name The name of the parameter.
+     * @param initializer The initializer for the parameter.
+     */
+    function addDefaultValueAssignmentForBindingPattern(statements: Statement[],
+                                                        parameter: ParameterDeclaration,
+                                                        name: BindingPattern, initializer: Expression,
+                                                        visitor: (node: Node) => VisitResult<Node>,
+                                                        convertObjectRest: boolean): void {
+        const temp = getGeneratedNameForNode(parameter);
+
+        // In cases where a binding pattern is simply '[]' or '{}',
+        // we usually don't want to emit a var declaration; however, in the presence
+        // of an initializer, we must emit that expression to preserve side effects.
+        if (name.elements.length > 0) {
+            statements.push(
+                setEmitFlags(
+                    createVariableStatement(
+                        /*modifiers*/ undefined,
+                        createVariableDeclarationList(
+                            flattenParameterDestructuring(parameter, temp, visitor, convertObjectRest)
+                        )
+                    ),
+                    EmitFlags.CustomPrologue
+                )
+            );
+        }
+        else if (initializer) {
+            statements.push(
+                setEmitFlags(
+                    createStatement(
+                        createAssignment(
+                            temp,
+                            visitNode(initializer, visitor, isExpression)
+                        )
+                    ),
+                    EmitFlags.CustomPrologue
+                )
+            );
+        }
+    }
+
+    /**
+     * Adds statements to the body of a function-like node for parameters with initializers.
+     *
+     * @param statements The statements for the new function body.
+     * @param parameter The parameter for the function.
+     * @param name The name of the parameter.
+     * @param initializer The initializer for the parameter.
+     */
+    function addDefaultValueAssignmentForInitializer(statements: Statement[],
+                                                     parameter: ParameterDeclaration,
+                                                     name: Identifier,
+                                                     initializer: Expression,
+                                                     visitor: (node: Node) => VisitResult<Node>): void {
+        initializer = visitNode(initializer, visitor, isExpression);
+        const statement = createIf(
+            createStrictEquality(
+                getSynthesizedClone(name),
+                createVoidZero()
+            ),
+            setEmitFlags(
+                createBlock([
+                    createStatement(
+                        createAssignment(
+                            setEmitFlags(getMutableClone(name), EmitFlags.NoSourceMap),
+                            setEmitFlags(initializer, EmitFlags.NoSourceMap | getEmitFlags(initializer)),
+                            /*location*/ parameter
+                        )
+                    )
+                ], /*location*/ parameter),
+                EmitFlags.SingleLine | EmitFlags.NoTrailingSourceMap | EmitFlags.NoTokenSourceMaps
+            ),
+            /*elseStatement*/ undefined,
+            /*location*/ parameter
+        );
+        statement.startsOnNewLine = true;
+        setEmitFlags(statement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoTrailingSourceMap | EmitFlags.CustomPrologue);
+        statements.push(statement);
+    }
+
+    /**
+     * Gets a value indicating whether we need to add statements to handle a rest parameter.
+     *
+     * @param node A ParameterDeclaration node.
+     * @param inConstructorWithSynthesizedSuper A value indicating whether the parameter is
+     *                                          part of a constructor declaration with a
+     *                                          synthesized call to `super`
+     */
+    function shouldAddRestParameter(node: ParameterDeclaration, inConstructorWithSynthesizedSuper: boolean) {
+        return node && node.dotDotDotToken && node.name.kind === SyntaxKind.Identifier && !inConstructorWithSynthesizedSuper;
+    }
+
+    /**
+     * Adds statements to the body of a function-like node if it contains a rest parameter.
+     *
+     * @param statements The statements for the new function body.
+     * @param node A function-like node.
+     * @param inConstructorWithSynthesizedSuper A value indicating whether the parameter is
+     *                                          part of a constructor declaration with a
+     *                                          synthesized call to `super`
+     */
+    export function addRestParameterIfNeeded(statements: Statement[], node: FunctionLikeDeclaration, inConstructorWithSynthesizedSuper: boolean): void {
+        const parameter = lastOrUndefined(node.parameters);
+        if (!shouldAddRestParameter(parameter, inConstructorWithSynthesizedSuper)) {
+            return;
+        }
+
+        // `declarationName` is the name of the local declaration for the parameter.
+        const declarationName = getMutableClone(<Identifier>parameter.name);
+        setEmitFlags(declarationName, EmitFlags.NoSourceMap);
+
+        // `expressionName` is the name of the parameter used in expressions.
+        const expressionName = getSynthesizedClone(<Identifier>parameter.name);
+        const restIndex = node.parameters.length - 1;
+        const temp = createLoopVariable();
+
+        // var param = [];
+        statements.push(
+            setEmitFlags(
+                createVariableStatement(
+                    /*modifiers*/ undefined,
+                    createVariableDeclarationList([
+                        createVariableDeclaration(
+                            declarationName,
+                            /*type*/ undefined,
+                            createArrayLiteral([])
+                        )
+                    ]),
+                    /*location*/ parameter
+                ),
+                EmitFlags.CustomPrologue
+            )
+        );
+
+        // for (var _i = restIndex; _i < arguments.length; _i++) {
+        //   param[_i - restIndex] = arguments[_i];
+        // }
+        const forStatement = createFor(
+            createVariableDeclarationList([
+                createVariableDeclaration(temp, /*type*/ undefined, createLiteral(restIndex))
+            ], /*location*/ parameter),
+            createLessThan(
+                temp,
+                createPropertyAccess(createIdentifier("arguments"), "length"),
+                /*location*/ parameter
+            ),
+            createPostfixIncrement(temp, /*location*/ parameter),
+            createBlock([
+                startOnNewLine(
+                    createStatement(
+                        createAssignment(
+                            createElementAccess(
+                                expressionName,
+                                createSubtract(temp, createLiteral(restIndex))
+                            ),
+                            createElementAccess(createIdentifier("arguments"), temp)
+                        ),
+                        /*location*/ parameter
+                    )
+                )
+            ])
+        );
+
+        setEmitFlags(forStatement, EmitFlags.CustomPrologue);
+        startOnNewLine(forStatement);
+        statements.push(forStatement);
+    }
+
+
+
+
     export function convertForOf(node: ForOfStatement, convertedLoopBodyStatements: Statement[],
                                  visitor: (node: Node) => VisitResult<Node>,
                                  enableSubstitutionsForBlockScopedBindings: () => void,
diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
index 76ea6b2ddd0b8..121ea5e12340b 100644
--- a/src/compiler/transformers/es2015.ts
+++ b/src/compiler/transformers/es2015.ts
@@ -861,7 +861,7 @@ namespace ts {
             }
 
             if (constructor) {
-                addDefaultValueAssignmentsIfNeeded(statements, constructor);
+                addDefaultValueAssignmentsIfNeeded(statements, constructor, visitor, /*convertObjectRest*/ false);
                 addRestParameterIfNeeded(statements, constructor, hasSynthesizedSuper);
                 Debug.assert(statementOffset >= 0, "statementOffset not initialized correctly!");
 
@@ -954,7 +954,7 @@ namespace ts {
             // If this isn't a derived class, just capture 'this' for arrow functions if necessary.
             if (!hasExtendsClause) {
                 if (ctor) {
-                    addCaptureThisForNodeIfNeeded(statements, ctor);
+                    addCaptureThisForNodeIfNeeded(statements, ctor, enableSubstitutionsForCapturedThis);
                 }
                 return SuperCaptureResult.NoReplacement;
             }
@@ -1016,7 +1016,7 @@ namespace ts {
             }
 
             // Perform the capture.
-            captureThisForNode(statements, ctor, superCallExpression, firstStatement);
+            captureThisForNode(statements, ctor, superCallExpression, enableSubstitutionsForCapturedThis, firstStatement);
 
             // If we're actually replacing the original statement, we need to signal this to the caller.
             if (superCallExpression) {
@@ -1085,242 +1085,6 @@ namespace ts {
             }
         }
 
-        /**
-         * Gets a value indicating whether we need to add default value assignments for a
-         * function-like node.
-         *
-         * @param node A function-like node.
-         */
-        function shouldAddDefaultValueAssignments(node: FunctionLikeDeclaration): boolean {
-            return (node.transformFlags & TransformFlags.ContainsDefaultValueAssignments) !== 0;
-        }
-
-        /**
-         * Adds statements to the body of a function-like node if it contains parameters with
-         * binding patterns or initializers.
-         *
-         * @param statements The statements for the new function body.
-         * @param node A function-like node.
-         */
-        function addDefaultValueAssignmentsIfNeeded(statements: Statement[], node: FunctionLikeDeclaration): void {
-            if (!shouldAddDefaultValueAssignments(node)) {
-                return;
-            }
-
-            for (const parameter of node.parameters) {
-                const { name, initializer, dotDotDotToken } = parameter;
-
-                // A rest parameter cannot have a binding pattern or an initializer,
-                // so let's just ignore it.
-                if (dotDotDotToken) {
-                    continue;
-                }
-
-                if (isBindingPattern(name)) {
-                    addDefaultValueAssignmentForBindingPattern(statements, parameter, name, initializer);
-                }
-                else if (initializer) {
-                    addDefaultValueAssignmentForInitializer(statements, parameter, name, initializer);
-                }
-            }
-        }
-
-        /**
-         * Adds statements to the body of a function-like node for parameters with binding patterns
-         *
-         * @param statements The statements for the new function body.
-         * @param parameter The parameter for the function.
-         * @param name The name of the parameter.
-         * @param initializer The initializer for the parameter.
-         */
-        function addDefaultValueAssignmentForBindingPattern(statements: Statement[], parameter: ParameterDeclaration, name: BindingPattern, initializer: Expression): void {
-            const temp = getGeneratedNameForNode(parameter);
-
-            // In cases where a binding pattern is simply '[]' or '{}',
-            // we usually don't want to emit a var declaration; however, in the presence
-            // of an initializer, we must emit that expression to preserve side effects.
-            if (name.elements.length > 0) {
-                statements.push(
-                    setEmitFlags(
-                        createVariableStatement(
-                            /*modifiers*/ undefined,
-                            createVariableDeclarationList(
-                                flattenParameterDestructuring(parameter, temp, visitor)
-                            )
-                        ),
-                        EmitFlags.CustomPrologue
-                    )
-                );
-            }
-            else if (initializer) {
-                statements.push(
-                    setEmitFlags(
-                        createStatement(
-                            createAssignment(
-                                temp,
-                                visitNode(initializer, visitor, isExpression)
-                            )
-                        ),
-                        EmitFlags.CustomPrologue
-                    )
-                );
-            }
-        }
-
-        /**
-         * Adds statements to the body of a function-like node for parameters with initializers.
-         *
-         * @param statements The statements for the new function body.
-         * @param parameter The parameter for the function.
-         * @param name The name of the parameter.
-         * @param initializer The initializer for the parameter.
-         */
-        function addDefaultValueAssignmentForInitializer(statements: Statement[], parameter: ParameterDeclaration, name: Identifier, initializer: Expression): void {
-            initializer = visitNode(initializer, visitor, isExpression);
-            const statement = createIf(
-                createStrictEquality(
-                    getSynthesizedClone(name),
-                    createVoidZero()
-                ),
-                setEmitFlags(
-                    createBlock([
-                        createStatement(
-                            createAssignment(
-                                setEmitFlags(getMutableClone(name), EmitFlags.NoSourceMap),
-                                setEmitFlags(initializer, EmitFlags.NoSourceMap | getEmitFlags(initializer)),
-                                /*location*/ parameter
-                            )
-                        )
-                    ], /*location*/ parameter),
-                    EmitFlags.SingleLine | EmitFlags.NoTrailingSourceMap | EmitFlags.NoTokenSourceMaps
-                ),
-                /*elseStatement*/ undefined,
-                /*location*/ parameter
-            );
-            statement.startsOnNewLine = true;
-            setEmitFlags(statement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoTrailingSourceMap | EmitFlags.CustomPrologue);
-            statements.push(statement);
-        }
-
-        /**
-         * Gets a value indicating whether we need to add statements to handle a rest parameter.
-         *
-         * @param node A ParameterDeclaration node.
-         * @param inConstructorWithSynthesizedSuper A value indicating whether the parameter is
-         *                                          part of a constructor declaration with a
-         *                                          synthesized call to `super`
-         */
-        function shouldAddRestParameter(node: ParameterDeclaration, inConstructorWithSynthesizedSuper: boolean) {
-            return node && node.dotDotDotToken && node.name.kind === SyntaxKind.Identifier && !inConstructorWithSynthesizedSuper;
-        }
-
-        /**
-         * Adds statements to the body of a function-like node if it contains a rest parameter.
-         *
-         * @param statements The statements for the new function body.
-         * @param node A function-like node.
-         * @param inConstructorWithSynthesizedSuper A value indicating whether the parameter is
-         *                                          part of a constructor declaration with a
-         *                                          synthesized call to `super`
-         */
-        function addRestParameterIfNeeded(statements: Statement[], node: FunctionLikeDeclaration, inConstructorWithSynthesizedSuper: boolean): void {
-            const parameter = lastOrUndefined(node.parameters);
-            if (!shouldAddRestParameter(parameter, inConstructorWithSynthesizedSuper)) {
-                return;
-            }
-
-            // `declarationName` is the name of the local declaration for the parameter.
-            const declarationName = getMutableClone(<Identifier>parameter.name);
-            setEmitFlags(declarationName, EmitFlags.NoSourceMap);
-
-            // `expressionName` is the name of the parameter used in expressions.
-            const expressionName = getSynthesizedClone(<Identifier>parameter.name);
-            const restIndex = node.parameters.length - 1;
-            const temp = createLoopVariable();
-
-            // var param = [];
-            statements.push(
-                setEmitFlags(
-                    createVariableStatement(
-                        /*modifiers*/ undefined,
-                        createVariableDeclarationList([
-                            createVariableDeclaration(
-                                declarationName,
-                                /*type*/ undefined,
-                                createArrayLiteral([])
-                            )
-                        ]),
-                        /*location*/ parameter
-                    ),
-                    EmitFlags.CustomPrologue
-                )
-            );
-
-            // for (var _i = restIndex; _i < arguments.length; _i++) {
-            //   param[_i - restIndex] = arguments[_i];
-            // }
-            const forStatement = createFor(
-                createVariableDeclarationList([
-                    createVariableDeclaration(temp, /*type*/ undefined, createLiteral(restIndex))
-                ], /*location*/ parameter),
-                createLessThan(
-                    temp,
-                    createPropertyAccess(createIdentifier("arguments"), "length"),
-                    /*location*/ parameter
-                ),
-                createPostfixIncrement(temp, /*location*/ parameter),
-                createBlock([
-                    startOnNewLine(
-                        createStatement(
-                            createAssignment(
-                                createElementAccess(
-                                    expressionName,
-                                    createSubtract(temp, createLiteral(restIndex))
-                                ),
-                                createElementAccess(createIdentifier("arguments"), temp)
-                            ),
-                            /*location*/ parameter
-                        )
-                    )
-                ])
-            );
-
-            setEmitFlags(forStatement, EmitFlags.CustomPrologue);
-            startOnNewLine(forStatement);
-            statements.push(forStatement);
-        }
-
-        /**
-         * Adds a statement to capture the `this` of a function declaration if it is needed.
-         *
-         * @param statements The statements for the new function body.
-         * @param node A node.
-         */
-        function addCaptureThisForNodeIfNeeded(statements: Statement[], node: Node): void {
-            if (node.transformFlags & TransformFlags.ContainsCapturedLexicalThis && node.kind !== SyntaxKind.ArrowFunction) {
-                captureThisForNode(statements, node, createThis());
-            }
-        }
-
-        function captureThisForNode(statements: Statement[], node: Node, initializer: Expression | undefined, originalStatement?: Statement): void {
-            enableSubstitutionsForCapturedThis();
-            const captureThisStatement = createVariableStatement(
-                /*modifiers*/ undefined,
-                createVariableDeclarationList([
-                    createVariableDeclaration(
-                        "_this",
-                        /*type*/ undefined,
-                        initializer
-                    )
-                ]),
-                originalStatement
-            );
-
-            setEmitFlags(captureThisStatement, EmitFlags.NoComments | EmitFlags.CustomPrologue);
-            setSourceMapRange(captureThisStatement, node);
-            statements.push(captureThisStatement);
-        }
-
         /**
          * Adds statements to the class body function for a class to define the members of the
          * class.
@@ -1518,7 +1282,7 @@ namespace ts {
                     /*typeParameters*/ undefined,
                     visitNodes(node.parameters, visitor, isParameter),
                     /*type*/ undefined,
-                    transformFunctionBody(node),
+                    transformFunctionBody(node, visitor, currentSourceFile, context, enableSubstitutionsForCapturedThis),
                     /*location*/ node
                 ),
                 /*original*/ node);
@@ -1545,7 +1309,7 @@ namespace ts {
                     /*typeParameters*/ undefined,
                     visitNodes(node.parameters, visitor, isParameter),
                     /*type*/ undefined,
-                    saveStateAndInvoke(node, transformFunctionBody),
+                    saveStateAndInvoke(node, node => transformFunctionBody(node, visitor, currentSourceFile, context, enableSubstitutionsForCapturedThis)),
                     location
                 ),
                 /*original*/ node
@@ -1555,96 +1319,6 @@ namespace ts {
             return expression;
         }
 
-        /**
-         * Transforms the body of a function-like node.
-         *
-         * @param node A function-like node.
-         */
-        function transformFunctionBody(node: FunctionLikeDeclaration) {
-            let multiLine = false; // indicates whether the block *must* be emitted as multiple lines
-            let singleLine = false; // indicates whether the block *may* be emitted as a single line
-            let statementsLocation: TextRange;
-            let closeBraceLocation: TextRange;
-
-            const statements: Statement[] = [];
-            const body = node.body;
-            let statementOffset: number;
-
-            startLexicalEnvironment();
-            if (isBlock(body)) {
-                // ensureUseStrict is false because no new prologue-directive should be added.
-                // addPrologueDirectives will simply put already-existing directives at the beginning of the target statement-array
-                statementOffset = addPrologueDirectives(statements, body.statements, /*ensureUseStrict*/ false, visitor);
-            }
-
-            addCaptureThisForNodeIfNeeded(statements, node);
-            addDefaultValueAssignmentsIfNeeded(statements, node);
-            addRestParameterIfNeeded(statements, node, /*inConstructorWithSynthesizedSuper*/ false);
-
-            // If we added any generated statements, this must be a multi-line block.
-            if (!multiLine && statements.length > 0) {
-                multiLine = true;
-            }
-
-            if (isBlock(body)) {
-                statementsLocation = body.statements;
-                addRange(statements, visitNodes(body.statements, visitor, isStatement, statementOffset));
-
-                // If the original body was a multi-line block, this must be a multi-line block.
-                if (!multiLine && body.multiLine) {
-                    multiLine = true;
-                }
-            }
-            else {
-                Debug.assert(node.kind === SyntaxKind.ArrowFunction);
-
-                // To align with the old emitter, we use a synthetic end position on the location
-                // for the statement list we synthesize when we down-level an arrow function with
-                // an expression function body. This prevents both comments and source maps from
-                // being emitted for the end position only.
-                statementsLocation = moveRangeEnd(body, -1);
-
-                const equalsGreaterThanToken = (<ArrowFunction>node).equalsGreaterThanToken;
-                if (!nodeIsSynthesized(equalsGreaterThanToken) && !nodeIsSynthesized(body)) {
-                    if (rangeEndIsOnSameLineAsRangeStart(equalsGreaterThanToken, body, currentSourceFile)) {
-                        singleLine = true;
-                    }
-                    else {
-                        multiLine = true;
-                    }
-                }
-
-                const expression = visitNode(body, visitor, isExpression);
-                const returnStatement = createReturn(expression, /*location*/ body);
-                setEmitFlags(returnStatement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoTrailingSourceMap | EmitFlags.NoTrailingComments);
-                statements.push(returnStatement);
-
-                // To align with the source map emit for the old emitter, we set a custom
-                // source map location for the close brace.
-                closeBraceLocation = body;
-            }
-
-            const lexicalEnvironment = endLexicalEnvironment();
-            addRange(statements, lexicalEnvironment);
-
-            // If we added any final generated statements, this must be a multi-line block
-            if (!multiLine && lexicalEnvironment && lexicalEnvironment.length) {
-                multiLine = true;
-            }
-
-            const block = createBlock(createNodeArray(statements, statementsLocation), node.body, multiLine);
-            if (!multiLine && singleLine) {
-                setEmitFlags(block, EmitFlags.SingleLine);
-            }
-
-            if (closeBraceLocation) {
-                setTokenSourceMapRange(block, SyntaxKind.CloseBraceToken, closeBraceLocation);
-            }
-
-            setOriginalNode(block, node.body);
-            return block;
-        }
-
         /**
          * Visits an ExpressionStatement that contains a destructuring assignment.
          *
@@ -2912,7 +2586,7 @@ namespace ts {
             const statements: Statement[] = [];
             startLexicalEnvironment();
             addRange(statements, prologue);
-            addCaptureThisForNodeIfNeeded(statements, node);
+            addCaptureThisForNodeIfNeeded(statements, node, enableSubstitutionsForCapturedThis);
             addRange(statements, visitNodes(createNodeArray(remaining), visitor, isStatement));
             addRange(statements, endLexicalEnvironment());
             const clone = getMutableClone(node);
diff --git a/src/compiler/transformers/esnext.ts b/src/compiler/transformers/esnext.ts
index 26864a123ea33..d57c86d06001b 100644
--- a/src/compiler/transformers/esnext.ts
+++ b/src/compiler/transformers/esnext.ts
@@ -5,8 +5,6 @@
 namespace ts {
     export function transformESNext(context: TransformationContext) {
         const {
-            startLexicalEnvironment,
-            endLexicalEnvironment,
             hoistVariableDeclaration,
         } = context;
         let currentSourceFile: SourceFile;
@@ -210,6 +208,11 @@ namespace ts {
         }
 
         function visitFunctionDeclaration(node: FunctionDeclaration): FunctionDeclaration {
+            const hasRest = forEach(node.parameters, isObjectRestParameter);
+            const body = hasRest ?
+                transformFunctionBody(node, visitor, currentSourceFile, context, noop, /*convertObjectRest*/ true) as Block :
+                visitEachChild(node.body, visitor, context);
+
             return setOriginalNode(
                 createFunctionDeclaration(
                     /*decorators*/ undefined,
@@ -219,13 +222,17 @@ namespace ts {
                     /*typeParameters*/ undefined,
                     visitNodes(node.parameters, visitor, isParameter),
                     /*type*/ undefined,
-                    transformFunctionBody(node) as Block,
+                    body,
                     /*location*/ node
                 ),
                 /*original*/ node);
         }
 
         function visitArrowFunction(node: ArrowFunction) {
+            const hasRest = forEach(node.parameters, isObjectRestParameter);
+            const body = hasRest ?
+                transformFunctionBody(node, visitor, currentSourceFile, context, noop, /*convertObjectRest*/ true) as Block :
+                visitEachChild(node.body, visitor, context);
             const func = setOriginalNode(
                 createArrowFunction(
                     /*modifiers*/ undefined,
@@ -233,7 +240,7 @@ namespace ts {
                     visitNodes(node.parameters, visitor, isParameter),
                     /*type*/ undefined,
                     node.equalsGreaterThanToken,
-                    transformFunctionBody(node),
+                    body,
                     /*location*/ node
                 ),
                 /*original*/ node
@@ -243,6 +250,10 @@ namespace ts {
         }
 
         function visitFunctionExpression(node: FunctionExpression): Expression {
+            const hasRest = forEach(node.parameters, isObjectRestParameter);
+            const body = hasRest ?
+                transformFunctionBody(node, visitor, currentSourceFile, context, noop, /*convertObjectRest*/ true) as Block :
+                visitEachChild(node.body, visitor, context);
             return setOriginalNode(
                 createFunctionExpression(
                     /*modifiers*/ undefined,
@@ -251,173 +262,11 @@ namespace ts {
                     /*typeParameters*/ undefined,
                     visitNodes(node.parameters, visitor, isParameter),
                     /*type*/ undefined,
-                    transformFunctionBody(node) as Block,
+                    body,
                     /*location*/ node
                 ),
                 /*original*/ node
             );
         }
-
-        /**
-         * Transforms the body of a function-like node.
-         *
-         * @param node A function-like node.
-         */
-        function transformFunctionBody(node: FunctionLikeDeclaration): Block | Expression {
-            const hasRest = forEach(node.parameters, isObjectRestParameter);
-            if (!hasRest) {
-                return visitEachChild(node.body, visitor, context);
-            }
-
-            let multiLine = false; // indicates whether the block *must* be emitted as multiple lines
-            let singleLine = false; // indicates whether the block *may* be emitted as a single line
-            let statementsLocation: TextRange;
-            let closeBraceLocation: TextRange;
-
-            const statements: Statement[] = [];
-            const body = node.body;
-            let statementOffset: number;
-
-            startLexicalEnvironment();
-            if (isBlock(body)) {
-                // ensureUseStrict is false because no new prologue-directive should be added.
-                // addPrologueDirectives will simply put already-existing directives at the beginning of the target statement-array
-                statementOffset = addPrologueDirectives(statements, body.statements, /*ensureUseStrict*/ false, visitor);
-            }
-
-            addDefaultValueAssignmentsIfNeeded(statements, node);
-
-            // If we added any generated statements, this must be a multi-line block.
-            if (!multiLine && statements.length > 0) {
-                multiLine = true;
-            }
-
-            if (isBlock(body)) {
-                statementsLocation = body.statements;
-                addRange(statements, visitNodes(body.statements, visitor, isStatement, statementOffset));
-
-                // If the original body was a multi-line block, this must be a multi-line block.
-                if (!multiLine && body.multiLine) {
-                    multiLine = true;
-                }
-            }
-            else {
-                Debug.assert(node.kind === SyntaxKind.ArrowFunction);
-
-                // To align with the old emitter, we use a synthetic end position on the location
-                // for the statement list we synthesize when we down-level an arrow function with
-                // an expression function body. This prevents both comments and source maps from
-                // being emitted for the end position only.
-                statementsLocation = moveRangeEnd(body, -1);
-
-                const equalsGreaterThanToken = (<ArrowFunction>node).equalsGreaterThanToken;
-                if (!nodeIsSynthesized(equalsGreaterThanToken) && !nodeIsSynthesized(body)) {
-                    if (rangeEndIsOnSameLineAsRangeStart(equalsGreaterThanToken, body, currentSourceFile)) {
-                        singleLine = true;
-                    }
-                    else {
-                        multiLine = true;
-                    }
-                }
-
-                const expression = visitNode(body, visitor, isExpression);
-                const returnStatement = createReturn(expression, /*location*/ body);
-                setEmitFlags(returnStatement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoTrailingSourceMap | EmitFlags.NoTrailingComments);
-                statements.push(returnStatement);
-
-                // To align with the source map emit for the old emitter, we set a custom
-                // source map location for the close brace.
-                closeBraceLocation = body;
-            }
-
-            const lexicalEnvironment = endLexicalEnvironment();
-            addRange(statements, lexicalEnvironment);
-
-            // If we added any final generated statements, this must be a multi-line block
-            if (!multiLine && lexicalEnvironment && lexicalEnvironment.length) {
-                multiLine = true;
-            }
-
-            const block = createBlock(createNodeArray(statements, statementsLocation), node.body, multiLine);
-            if (!multiLine && singleLine) {
-                setEmitFlags(block, EmitFlags.SingleLine);
-            }
-
-            if (closeBraceLocation) {
-                setTokenSourceMapRange(block, SyntaxKind.CloseBraceToken, closeBraceLocation);
-            }
-
-            setOriginalNode(block, node.body);
-            return block;
-        }
-
-        function shouldAddDefaultValueAssignments(node: FunctionLikeDeclaration): boolean {
-            return !!(node.transformFlags & TransformFlags.ContainsDefaultValueAssignments);
-        }
-
-        /**
-         * Adds statements to the body of a function-like node if it contains parameters with
-         * binding patterns or initializers.
-         *
-         * @param statements The statements for the new function body.
-         * @param node A function-like node.
-         */
-        function addDefaultValueAssignmentsIfNeeded(statements: Statement[], node: FunctionLikeDeclaration): void {
-            if (!shouldAddDefaultValueAssignments(node)) {
-                return;
-            }
-
-            for (const parameter of node.parameters) {
-                // A rest parameter cannot have a binding pattern or an initializer,
-                // so let's just ignore it.
-                if (parameter.dotDotDotToken) {
-                    continue;
-                }
-
-                if (isBindingPattern(parameter.name)) {
-                    addDefaultValueAssignmentForBindingPattern(statements, parameter);
-                }
-            }
-        }
-
-        /**
-         * Adds statements to the body of a function-like node for parameters with binding patterns
-         *
-         * @param statements The statements for the new function body.
-         * @param parameter The parameter for the function.
-         */
-        function addDefaultValueAssignmentForBindingPattern(statements: Statement[], parameter: ParameterDeclaration): void {
-            const temp = getGeneratedNameForNode(parameter);
-
-            // In cases where a binding pattern is simply '[]' or '{}',
-            // we usually don't want to emit a var declaration; however, in the presence
-            // of an initializer, we must emit that expression to preserve side effects.
-            if ((parameter.name as BindingPattern).elements.length > 0) {
-                statements.push(
-                    setEmitFlags(
-                        createVariableStatement(
-                            /*modifiers*/ undefined,
-                            createVariableDeclarationList(
-                                flattenParameterDestructuring(parameter, temp, visitor, /*transformRest*/ true)
-                            )
-                        ),
-                        EmitFlags.CustomPrologue
-                    )
-                );
-            }
-            else if (parameter.initializer) {
-                statements.push(
-                    setEmitFlags(
-                        createStatement(
-                            createAssignment(
-                                temp,
-                                visitNode(parameter.initializer, visitor, isExpression)
-                            )
-                        ),
-                        EmitFlags.CustomPrologue
-                    )
-                );
-            }
-        }
     }
 }

From a55ed26d2be4ac49e6a0b4060eac6ea4ff2333b9 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 4 Nov 2016 16:06:33 -0700
Subject: [PATCH 174/224] Spread any types to any

---
 src/compiler/checker.ts                       |   9 +-
 tests/baselines/reference/objectSpread.js     |   7 +
 .../baselines/reference/objectSpread.symbols  | 129 +++++++++---------
 tests/baselines/reference/objectSpread.types  |   9 ++
 .../objectSpreadNegativeParse.errors.txt      |  11 +-
 .../conformance/types/spread/objectSpread.ts  |   4 +
 6 files changed, 95 insertions(+), 74 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 3475a9d52c6f7..20e90f4db2546 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5884,8 +5884,11 @@ namespace ts {
          * this function should be called in a left folding style, with left = previous result of getSpreadType
          * and right = the new element to be spread.
          */
-        function getSpreadType(left: Type, right: Type, symbol: Symbol): ResolvedType {
-            Debug.assert(!!(left.flags & TypeFlags.Object) && !!(right.flags & TypeFlags.Object), "Only object types may be spread.");
+        function getSpreadType(left: Type, right: Type, symbol: Symbol): ResolvedType | IntrinsicType {
+            Debug.assert(!!(left.flags & (TypeFlags.Object | TypeFlags.Any)) && !!(right.flags & (TypeFlags.Object | TypeFlags.Any)), "Only object types may be spread.");
+            if (left.flags & TypeFlags.Any || right.flags & TypeFlags.Any) {
+                return anyType;
+            }
             const members = createMap<Symbol>();
             const skippedPrivateMembers = createMap<boolean>();
             let stringIndexInfo: IndexInfo;
@@ -10934,7 +10937,7 @@ namespace ts {
                         typeFlags = 0;
                     }
                     const type = checkExpression((memberDecl as SpreadElementExpression).expression);
-                    if (!(type.flags & TypeFlags.Object)) {
+                    if (!(type.flags & (TypeFlags.Object | TypeFlags.Any))) {
                         error(memberDecl, Diagnostics.Spread_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
diff --git a/tests/baselines/reference/objectSpread.js b/tests/baselines/reference/objectSpread.js
index c19ead478cbd8..d1de48c5cabb2 100644
--- a/tests/baselines/reference/objectSpread.js
+++ b/tests/baselines/reference/objectSpread.js
@@ -38,6 +38,10 @@ getter.a = 12;
 // functions result in { }
 let spreadFunc = { ...(function () { }) };
 
+// any results in any
+let anything: any;
+let spreadAny = { ...anything };
+
 // methods are not enumerable
 class C { p = 1; m() { } }
 let c: C = new C()
@@ -109,6 +113,9 @@ var getter = __assign({}, op, { c: 7 });
 getter.a = 12;
 // functions result in { }
 var spreadFunc = __assign({}, (function () { }));
+// any results in any
+var anything;
+var spreadAny = __assign({}, anything);
 // methods are not enumerable
 var C = (function () {
     function C() {
diff --git a/tests/baselines/reference/objectSpread.symbols b/tests/baselines/reference/objectSpread.symbols
index b95f8273724c2..4b0a62a5a24ec 100644
--- a/tests/baselines/reference/objectSpread.symbols
+++ b/tests/baselines/reference/objectSpread.symbols
@@ -154,123 +154,130 @@ getter.a = 12;
 let spreadFunc = { ...(function () { }) };
 >spreadFunc : Symbol(spreadFunc, Decl(objectSpread.ts, 37, 3))
 
+// any results in any
+let anything: any;
+>anything : Symbol(anything, Decl(objectSpread.ts, 40, 3))
+
+let spreadAny = { ...anything };
+>spreadAny : Symbol(spreadAny, Decl(objectSpread.ts, 41, 3))
+
 // methods are not enumerable
 class C { p = 1; m() { } }
->C : Symbol(C, Decl(objectSpread.ts, 37, 42))
->p : Symbol(C.p, Decl(objectSpread.ts, 40, 9))
->m : Symbol(C.m, Decl(objectSpread.ts, 40, 16))
+>C : Symbol(C, Decl(objectSpread.ts, 41, 32))
+>p : Symbol(C.p, Decl(objectSpread.ts, 44, 9))
+>m : Symbol(C.m, Decl(objectSpread.ts, 44, 16))
 
 let c: C = new C()
->c : Symbol(c, Decl(objectSpread.ts, 41, 3))
->C : Symbol(C, Decl(objectSpread.ts, 37, 42))
->C : Symbol(C, Decl(objectSpread.ts, 37, 42))
+>c : Symbol(c, Decl(objectSpread.ts, 45, 3))
+>C : Symbol(C, Decl(objectSpread.ts, 41, 32))
+>C : Symbol(C, Decl(objectSpread.ts, 41, 32))
 
 let spreadC: { p: number } = { ...c }
->spreadC : Symbol(spreadC, Decl(objectSpread.ts, 42, 3))
->p : Symbol(p, Decl(objectSpread.ts, 42, 14))
+>spreadC : Symbol(spreadC, Decl(objectSpread.ts, 46, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 46, 14))
 
 // own methods are enumerable
 let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } };
->cplus : Symbol(cplus, Decl(objectSpread.ts, 45, 3))
->p : Symbol(p, Decl(objectSpread.ts, 45, 12))
->plus : Symbol(plus, Decl(objectSpread.ts, 45, 23))
->plus : Symbol(plus, Decl(objectSpread.ts, 45, 48))
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 49, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 49, 12))
+>plus : Symbol(plus, Decl(objectSpread.ts, 49, 23))
+>plus : Symbol(plus, Decl(objectSpread.ts, 49, 48))
 
 cplus.plus();
->cplus.plus : Symbol(plus, Decl(objectSpread.ts, 45, 23))
->cplus : Symbol(cplus, Decl(objectSpread.ts, 45, 3))
->plus : Symbol(plus, Decl(objectSpread.ts, 45, 23))
+>cplus.plus : Symbol(plus, Decl(objectSpread.ts, 49, 23))
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 49, 3))
+>plus : Symbol(plus, Decl(objectSpread.ts, 49, 23))
 
 // new field's type conflicting with existing field is OK
 let changeTypeAfter: { a: string, b: string } =
->changeTypeAfter : Symbol(changeTypeAfter, Decl(objectSpread.ts, 49, 3))
->a : Symbol(a, Decl(objectSpread.ts, 49, 22))
->b : Symbol(b, Decl(objectSpread.ts, 49, 33))
+>changeTypeAfter : Symbol(changeTypeAfter, Decl(objectSpread.ts, 53, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 53, 22))
+>b : Symbol(b, Decl(objectSpread.ts, 53, 33))
 
     { ...o, a: 'wrong type?' }
->a : Symbol(a, Decl(objectSpread.ts, 50, 11))
+>a : Symbol(a, Decl(objectSpread.ts, 54, 11))
 
 let changeTypeBefore: { a: number, b: string } =
->changeTypeBefore : Symbol(changeTypeBefore, Decl(objectSpread.ts, 51, 3))
->a : Symbol(a, Decl(objectSpread.ts, 51, 23))
->b : Symbol(b, Decl(objectSpread.ts, 51, 34))
+>changeTypeBefore : Symbol(changeTypeBefore, Decl(objectSpread.ts, 55, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 55, 23))
+>b : Symbol(b, Decl(objectSpread.ts, 55, 34))
 
     { a: 'wrong type?', ...o };
->a : Symbol(a, Decl(objectSpread.ts, 52, 5))
+>a : Symbol(a, Decl(objectSpread.ts, 56, 5))
 
 let changeTypeBoth: { a: string, b: number } =
->changeTypeBoth : Symbol(changeTypeBoth, Decl(objectSpread.ts, 53, 3))
->a : Symbol(a, Decl(objectSpread.ts, 53, 21))
->b : Symbol(b, Decl(objectSpread.ts, 53, 32))
+>changeTypeBoth : Symbol(changeTypeBoth, Decl(objectSpread.ts, 57, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 57, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 57, 32))
 
     { ...o, ...swap };
 
 // optional
 let definiteBoolean: { sn: boolean };
->definiteBoolean : Symbol(definiteBoolean, Decl(objectSpread.ts, 57, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 57, 22))
+>definiteBoolean : Symbol(definiteBoolean, Decl(objectSpread.ts, 61, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 61, 22))
 
 let definiteString: { sn: string };
->definiteString : Symbol(definiteString, Decl(objectSpread.ts, 58, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 58, 21))
+>definiteString : Symbol(definiteString, Decl(objectSpread.ts, 62, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 62, 21))
 
 let optionalString: { sn?: string };
->optionalString : Symbol(optionalString, Decl(objectSpread.ts, 59, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 59, 21))
+>optionalString : Symbol(optionalString, Decl(objectSpread.ts, 63, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 63, 21))
 
 let optionalNumber: { sn?: number };
->optionalNumber : Symbol(optionalNumber, Decl(objectSpread.ts, 60, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 60, 21))
+>optionalNumber : Symbol(optionalNumber, Decl(objectSpread.ts, 64, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 64, 21))
 
 let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
->optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpread.ts, 61, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 61, 25))
+>optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpread.ts, 65, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 65, 25))
 
 let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
->optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpread.ts, 62, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 62, 30))
+>optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpread.ts, 66, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 66, 30))
 
 let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
->allOptional : Symbol(allOptional, Decl(objectSpread.ts, 63, 3))
->sn : Symbol(sn, Decl(objectSpread.ts, 63, 18))
+>allOptional : Symbol(allOptional, Decl(objectSpread.ts, 67, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 67, 18))
 
 // computed property
 let computedFirst: { a: number, b: string, "before everything": number } =
->computedFirst : Symbol(computedFirst, Decl(objectSpread.ts, 66, 3))
->a : Symbol(a, Decl(objectSpread.ts, 66, 20))
->b : Symbol(b, Decl(objectSpread.ts, 66, 31))
+>computedFirst : Symbol(computedFirst, Decl(objectSpread.ts, 70, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 70, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 70, 31))
 
     { ['before everything']: 12, ...o, b: 'yes' }
->'before everything' : Symbol(['before everything'], Decl(objectSpread.ts, 67, 5))
->b : Symbol(b, Decl(objectSpread.ts, 67, 38))
+>'before everything' : Symbol(['before everything'], Decl(objectSpread.ts, 71, 5))
+>b : Symbol(b, Decl(objectSpread.ts, 71, 38))
 
 let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
->computedMiddle : Symbol(computedMiddle, Decl(objectSpread.ts, 68, 3))
->a : Symbol(a, Decl(objectSpread.ts, 68, 21))
->b : Symbol(b, Decl(objectSpread.ts, 68, 32))
->c : Symbol(c, Decl(objectSpread.ts, 68, 43))
+>computedMiddle : Symbol(computedMiddle, Decl(objectSpread.ts, 72, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 72, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 72, 32))
+>c : Symbol(c, Decl(objectSpread.ts, 72, 43))
 
     { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
->'in the middle' : Symbol(['in the middle'], Decl(objectSpread.ts, 69, 11))
->b : Symbol(b, Decl(objectSpread.ts, 69, 34))
+>'in the middle' : Symbol(['in the middle'], Decl(objectSpread.ts, 73, 11))
+>b : Symbol(b, Decl(objectSpread.ts, 73, 34))
 
 let computedAfter: { a: number, b: string, "at the end": number } =
->computedAfter : Symbol(computedAfter, Decl(objectSpread.ts, 70, 3))
->a : Symbol(a, Decl(objectSpread.ts, 70, 20))
->b : Symbol(b, Decl(objectSpread.ts, 70, 31))
+>computedAfter : Symbol(computedAfter, Decl(objectSpread.ts, 74, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 74, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 74, 31))
 
     { ...o, b: 'yeah', ['at the end']: 14 }
->b : Symbol(b, Decl(objectSpread.ts, 71, 11))
->'at the end' : Symbol(['at the end'], Decl(objectSpread.ts, 71, 22))
+>b : Symbol(b, Decl(objectSpread.ts, 75, 11))
+>'at the end' : Symbol(['at the end'], Decl(objectSpread.ts, 75, 22))
 
 // shortcut syntax
 let a = 12;
->a : Symbol(a, Decl(objectSpread.ts, 73, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 77, 3))
 
 let shortCutted: { a: number, b: string } = { ...o, a }
->shortCutted : Symbol(shortCutted, Decl(objectSpread.ts, 74, 3))
->a : Symbol(a, Decl(objectSpread.ts, 74, 18))
->b : Symbol(b, Decl(objectSpread.ts, 74, 29))
->a : Symbol(a, Decl(objectSpread.ts, 74, 51))
+>shortCutted : Symbol(shortCutted, Decl(objectSpread.ts, 78, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 78, 18))
+>b : Symbol(b, Decl(objectSpread.ts, 78, 29))
+>a : Symbol(a, Decl(objectSpread.ts, 78, 51))
 
 
diff --git a/tests/baselines/reference/objectSpread.types b/tests/baselines/reference/objectSpread.types
index e9b9a6421c297..a1c70720d1296 100644
--- a/tests/baselines/reference/objectSpread.types
+++ b/tests/baselines/reference/objectSpread.types
@@ -230,6 +230,15 @@ let spreadFunc = { ...(function () { }) };
 >(function () { }) : () => void
 >function () { } : () => void
 
+// any results in any
+let anything: any;
+>anything : any
+
+let spreadAny = { ...anything };
+>spreadAny : any
+>{ ...anything } : any
+>anything : any
+
 // methods are not enumerable
 class C { p = 1; m() { } }
 >C : C
diff --git a/tests/baselines/reference/objectSpreadNegativeParse.errors.txt b/tests/baselines/reference/objectSpreadNegativeParse.errors.txt
index 987172ef867bf..b37200c4f0293 100644
--- a/tests/baselines/reference/objectSpreadNegativeParse.errors.txt
+++ b/tests/baselines/reference/objectSpreadNegativeParse.errors.txt
@@ -1,22 +1,17 @@
-tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(1,12): error TS2698: Spread types may only be created from object types.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(1,15): error TS2304: Cannot find name 'o'.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(1,18): error TS1109: Expression expected.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(2,12): error TS2698: Spread types may only be created from object types.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(2,15): error TS1109: Expression expected.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(2,16): error TS2304: Cannot find name 'o'.
-tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(3,12): error TS2698: Spread types may only be created from object types.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(3,15): error TS2304: Cannot find name 'matchMedia'.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(3,28): error TS1005: ',' expected.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(3,31): error TS1128: Declaration or statement expected.
-tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(4,13): error TS2698: Spread types may only be created from object types.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(4,16): error TS2304: Cannot find name 'get'.
 tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(4,20): error TS1005: ',' expected.
 
 
-==== tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts (13 errors) ====
+==== tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts (10 errors) ====
     let o7 = { ...o? };
-               ~~~~~
-!!! error TS2698: Spread types may only be created from object types.
                   ~
 !!! error TS2304: Cannot find name 'o'.
                      ~
@@ -29,8 +24,6 @@ tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(4,20): error T
                    ~
 !!! error TS2304: Cannot find name 'o'.
     let o9 = { ...matchMedia() { }};
-               ~~~~~~~~~~~~~~~
-!!! error TS2698: Spread types may only be created from object types.
                   ~~~~~~~~~~
 !!! error TS2304: Cannot find name 'matchMedia'.
                                ~
@@ -38,8 +31,6 @@ tests/cases/conformance/types/spread/objectSpreadNegativeParse.ts(4,20): error T
                                   ~
 !!! error TS1128: Declaration or statement expected.
     let o10 = { ...get x() { return 12; }};
-                ~~~~~~
-!!! error TS2698: Spread types may only be created from object types.
                    ~~~
 !!! error TS2304: Cannot find name 'get'.
                        ~
diff --git a/tests/cases/conformance/types/spread/objectSpread.ts b/tests/cases/conformance/types/spread/objectSpread.ts
index 3336196e136c3..ebf2bdb2adede 100644
--- a/tests/cases/conformance/types/spread/objectSpread.ts
+++ b/tests/cases/conformance/types/spread/objectSpread.ts
@@ -38,6 +38,10 @@ getter.a = 12;
 // functions result in { }
 let spreadFunc = { ...(function () { }) };
 
+// any results in any
+let anything: any;
+let spreadAny = { ...anything };
+
 // methods are not enumerable
 class C { p = 1; m() { } }
 let c: C = new C()

From ed4fead087ab0fea1811e4b42b6d8e599ee13f1e Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Fri, 4 Nov 2016 21:54:22 -0700
Subject: [PATCH 175/224] add missing bind calls to properly set parent on
 token nodes (#12057)

---
 src/compiler/binder.ts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index c1011e575683b..1d721e2db90f7 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -1234,9 +1234,11 @@ namespace ts {
             const postExpressionLabel = createBranchLabel();
             bindCondition(node.condition, trueLabel, falseLabel);
             currentFlow = finishFlowLabel(trueLabel);
+            bind(node.questionToken);
             bind(node.whenTrue);
             addAntecedent(postExpressionLabel, currentFlow);
             currentFlow = finishFlowLabel(falseLabel);
+            bind(node.colonToken);
             bind(node.whenFalse);
             addAntecedent(postExpressionLabel, currentFlow);
             currentFlow = finishFlowLabel(postExpressionLabel);

From 61b9da548a6eb8d6b11849d129996625968833f4 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sat, 5 Nov 2016 08:20:02 -0700
Subject: [PATCH 176/224] Cache generic signature instantiations

---
 src/compiler/checker.ts | 8 +++++++-
 src/compiler/types.ts   | 2 ++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 0f2c642124afc..9647077d943e6 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4232,7 +4232,7 @@ namespace ts {
             for (const baseSig of baseSignatures) {
                 const typeParamCount = baseSig.typeParameters ? baseSig.typeParameters.length : 0;
                 if (typeParamCount === typeArgCount) {
-                    const sig = typeParamCount ? getSignatureInstantiation(baseSig, typeArguments) : cloneSignature(baseSig);
+                    const sig = typeParamCount ? createSignatureInstantiation(baseSig, typeArguments) : cloneSignature(baseSig);
                     sig.typeParameters = classType.localTypeParameters;
                     sig.resolvedReturnType = classType;
                     result.push(sig);
@@ -4982,6 +4982,12 @@ namespace ts {
         }
 
         function getSignatureInstantiation(signature: Signature, typeArguments: Type[]): Signature {
+            const instantiations = signature.instantiations || (signature.instantiations = createMap<Signature>());
+            const id = getTypeListId(typeArguments);
+            return instantiations[id] || (instantiations[id] = createSignatureInstantiation(signature, typeArguments));
+        }
+
+        function createSignatureInstantiation(signature: Signature, typeArguments: Type[]): Signature {
             return instantiateSignature(signature, createTypeMapper(signature.typeParameters, typeArguments), /*eraseTypeParameters*/ true);
         }
 
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 5536a818df536..37a3cc466a0df 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2923,6 +2923,8 @@ namespace ts {
         isolatedSignatureType?: ObjectType; // A manufactured type that just contains the signature for purposes of signature comparison
         /* @internal */
         typePredicate?: TypePredicate;
+        /* @internal */
+        instantiations?: Map<Signature>;    // Generic signature instantiation cache
     }
 
     export const enum IndexKind {

From 4c1e4169bded1a3e6fbfb72edf8ae3a47e78b5ad Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sat, 5 Nov 2016 08:23:42 -0700
Subject: [PATCH 177/224] Accept new baselines

---
 tests/baselines/reference/promisePermutations.errors.txt  | 4 ----
 tests/baselines/reference/promisePermutations2.errors.txt | 4 ----
 tests/baselines/reference/promisePermutations3.errors.txt | 4 ----
 3 files changed, 12 deletions(-)

diff --git a/tests/baselines/reference/promisePermutations.errors.txt b/tests/baselines/reference/promisePermutations.errors.txt
index 65fa098164382..13fc071859691 100644
--- a/tests/baselines/reference/promisePermutations.errors.txt
+++ b/tests/baselines/reference/promisePermutations.errors.txt
@@ -25,8 +25,6 @@ tests/cases/compiler/promisePermutations.ts(106,19): error TS2345: Argument of t
   Types of parameters 'cb' and 'value' are incompatible.
     Type 'string' is not assignable to type '<T>(a: T) => T'.
 tests/cases/compiler/promisePermutations.ts(109,19): error TS2345: Argument of type '(cb: <T>(a: T) => T) => IPromise<string>' is not assignable to parameter of type '(value: string) => IPromise<string>'.
-  Types of parameters 'cb' and 'value' are incompatible.
-    Type 'string' is not assignable to type '<T>(a: T) => T'.
 tests/cases/compiler/promisePermutations.ts(110,19): error TS2345: Argument of type '(cb: <T>(a: T) => T) => Promise<string>' is not assignable to parameter of type '(value: string) => Promise<string>'.
   Types of parameters 'cb' and 'value' are incompatible.
     Type 'string' is not assignable to type '<T>(a: T) => T'.
@@ -229,8 +227,6 @@ tests/cases/compiler/promisePermutations.ts(160,21): error TS2345: Argument of t
     var s7a = r7.then(testFunction7, testFunction7, testFunction7); // error
                       ~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(cb: <T>(a: T) => T) => IPromise<string>' is not assignable to parameter of type '(value: string) => IPromise<string>'.
-!!! error TS2345:   Types of parameters 'cb' and 'value' are incompatible.
-!!! error TS2345:     Type 'string' is not assignable to type '<T>(a: T) => T'.
     var s7b = r7.then(testFunction7P, testFunction7P, testFunction7P); // error
                       ~~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(cb: <T>(a: T) => T) => Promise<string>' is not assignable to parameter of type '(value: string) => Promise<string>'.
diff --git a/tests/baselines/reference/promisePermutations2.errors.txt b/tests/baselines/reference/promisePermutations2.errors.txt
index 0fc6f04911a6e..b21a3a3920886 100644
--- a/tests/baselines/reference/promisePermutations2.errors.txt
+++ b/tests/baselines/reference/promisePermutations2.errors.txt
@@ -25,8 +25,6 @@ tests/cases/compiler/promisePermutations2.ts(105,19): error TS2345: Argument of
   Types of parameters 'cb' and 'value' are incompatible.
     Type 'string' is not assignable to type '<T>(a: T) => T'.
 tests/cases/compiler/promisePermutations2.ts(108,19): error TS2345: Argument of type '(cb: <T>(a: T) => T) => IPromise<string>' is not assignable to parameter of type '(value: string) => IPromise<string>'.
-  Types of parameters 'cb' and 'value' are incompatible.
-    Type 'string' is not assignable to type '<T>(a: T) => T'.
 tests/cases/compiler/promisePermutations2.ts(109,19): error TS2345: Argument of type '(cb: <T>(a: T) => T) => Promise<string>' is not assignable to parameter of type '(value: string) => Promise<string>'.
   Types of parameters 'cb' and 'value' are incompatible.
     Type 'string' is not assignable to type '<T>(a: T) => T'.
@@ -228,8 +226,6 @@ tests/cases/compiler/promisePermutations2.ts(159,21): error TS2345: Argument of
     var s7a = r7.then(testFunction7, testFunction7, testFunction7); // error
                       ~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(cb: <T>(a: T) => T) => IPromise<string>' is not assignable to parameter of type '(value: string) => IPromise<string>'.
-!!! error TS2345:   Types of parameters 'cb' and 'value' are incompatible.
-!!! error TS2345:     Type 'string' is not assignable to type '<T>(a: T) => T'.
     var s7b = r7.then(testFunction7P, testFunction7P, testFunction7P); // error
                       ~~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(cb: <T>(a: T) => T) => Promise<string>' is not assignable to parameter of type '(value: string) => Promise<string>'.
diff --git a/tests/baselines/reference/promisePermutations3.errors.txt b/tests/baselines/reference/promisePermutations3.errors.txt
index a1a1b3f493f22..1a33d1083aac3 100644
--- a/tests/baselines/reference/promisePermutations3.errors.txt
+++ b/tests/baselines/reference/promisePermutations3.errors.txt
@@ -28,8 +28,6 @@ tests/cases/compiler/promisePermutations3.ts(105,19): error TS2345: Argument of
   Types of parameters 'cb' and 'value' are incompatible.
     Type 'string' is not assignable to type '<T>(a: T) => T'.
 tests/cases/compiler/promisePermutations3.ts(108,19): error TS2345: Argument of type '(cb: <T>(a: T) => T) => IPromise<string>' is not assignable to parameter of type '(value: string) => IPromise<string>'.
-  Types of parameters 'cb' and 'value' are incompatible.
-    Type 'string' is not assignable to type '<T>(a: T) => T'.
 tests/cases/compiler/promisePermutations3.ts(109,19): error TS2345: Argument of type '(cb: <T>(a: T) => T) => Promise<string>' is not assignable to parameter of type '(value: string) => Promise<string>'.
   Types of parameters 'cb' and 'value' are incompatible.
     Type 'string' is not assignable to type '<T>(a: T) => T'.
@@ -240,8 +238,6 @@ tests/cases/compiler/promisePermutations3.ts(165,21): error TS2345: Argument of
     var s7a = r7.then(testFunction7, testFunction7, testFunction7); // error
                       ~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(cb: <T>(a: T) => T) => IPromise<string>' is not assignable to parameter of type '(value: string) => IPromise<string>'.
-!!! error TS2345:   Types of parameters 'cb' and 'value' are incompatible.
-!!! error TS2345:     Type 'string' is not assignable to type '<T>(a: T) => T'.
     var s7b = r7.then(testFunction7P, testFunction7P, testFunction7P); // error
                       ~~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(cb: <T>(a: T) => T) => Promise<string>' is not assignable to parameter of type '(value: string) => Promise<string>'.

From da7f11fe4bc7a2b95705601590df17a720f8e072 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sat, 5 Nov 2016 17:36:00 -0700
Subject: [PATCH 178/224] Properly instantiate aliasTypeArguments

---
 src/compiler/checker.ts | 25 ++++++++++++++++---------
 src/compiler/types.ts   |  1 -
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 0f2c642124afc..d0028896baade 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4164,8 +4164,8 @@ namespace ts {
             else {
                 mapper = createTypeMapper(typeParameters, typeArguments);
                 members = createInstantiatedSymbolTable(source.declaredProperties, mapper, /*mappingThisOnly*/ typeParameters.length === 1);
-                callSignatures = instantiateList(source.declaredCallSignatures, mapper, instantiateSignature);
-                constructSignatures = instantiateList(source.declaredConstructSignatures, mapper, instantiateSignature);
+                callSignatures = instantiateSignatures(source.declaredCallSignatures, mapper);
+                constructSignatures = instantiateSignatures(source.declaredConstructSignatures, mapper);
                 stringIndexInfo = instantiateIndexInfo(source.declaredStringIndexInfo, mapper);
                 numberIndexInfo = instantiateIndexInfo(source.declaredNumberIndexInfo, mapper);
             }
@@ -4363,8 +4363,8 @@ namespace ts {
             const symbol = type.symbol;
             if (type.target) {
                 const members = createInstantiatedSymbolTable(getPropertiesOfObjectType(type.target), type.mapper, /*mappingThisOnly*/ false);
-                const callSignatures = instantiateList(getSignaturesOfType(type.target, SignatureKind.Call), type.mapper, instantiateSignature);
-                const constructSignatures = instantiateList(getSignaturesOfType(type.target, SignatureKind.Construct), type.mapper, instantiateSignature);
+                const callSignatures = instantiateSignatures(getSignaturesOfType(type.target, SignatureKind.Call), type.mapper);
+                const constructSignatures = instantiateSignatures(getSignaturesOfType(type.target, SignatureKind.Construct), type.mapper);
                 const stringIndexInfo = instantiateIndexInfo(getIndexInfoOfType(type.target, IndexKind.String), type.mapper);
                 const numberIndexInfo = instantiateIndexInfo(getIndexInfoOfType(type.target, IndexKind.Number), type.mapper);
                 setStructuredTypeMembers(type, members, callSignatures, constructSignatures, stringIndexInfo, numberIndexInfo);
@@ -6037,6 +6037,14 @@ namespace ts {
             return items;
         }
 
+        function instantiateTypes(types: Type[], mapper: TypeMapper) {
+            return instantiateList(types, mapper, instantiateType);
+        }
+
+        function instantiateSignatures(signatures: Signature[], mapper: TypeMapper) {
+            return instantiateList(signatures, mapper, instantiateSignature);
+        }
+
         function createUnaryTypeMapper(source: Type, target: Type): TypeMapper {
             return t => t === source ? target : t;
         }
@@ -6063,7 +6071,6 @@ namespace ts {
                     count == 2 ? createBinaryTypeMapper(sources[0], targets ? targets[0] : anyType, sources[1], targets ? targets[1] : anyType) :
                         createArrayTypeMapper(sources, targets);
             mapper.mappedTypes = sources;
-            mapper.targetTypes = targets;
             return mapper;
         }
 
@@ -6190,7 +6197,7 @@ namespace ts {
             result.target = type;
             result.mapper = mapper;
             result.aliasSymbol = type.aliasSymbol;
-            result.aliasTypeArguments = mapper.targetTypes;
+            result.aliasTypeArguments = instantiateTypes(type.aliasTypeArguments, mapper);
             mapper.instantiations[type.id] = result;
             return result;
         }
@@ -6266,14 +6273,14 @@ namespace ts {
                             instantiateAnonymousType(<AnonymousType>type, mapper) : type;
                     }
                     if ((<ObjectType>type).objectFlags & ObjectFlags.Reference) {
-                        return createTypeReference((<TypeReference>type).target, instantiateList((<TypeReference>type).typeArguments, mapper, instantiateType));
+                        return createTypeReference((<TypeReference>type).target, instantiateTypes((<TypeReference>type).typeArguments, mapper));
                     }
                 }
                 if (type.flags & TypeFlags.Union && !(type.flags & TypeFlags.Primitive)) {
-                    return getUnionType(instantiateList((<UnionType>type).types, mapper, instantiateType), /*subtypeReduction*/ false, type.aliasSymbol, mapper.targetTypes);
+                    return getUnionType(instantiateTypes((<UnionType>type).types, mapper), /*subtypeReduction*/ false, type.aliasSymbol, instantiateTypes(type.aliasTypeArguments, mapper));
                 }
                 if (type.flags & TypeFlags.Intersection) {
-                    return getIntersectionType(instantiateList((<IntersectionType>type).types, mapper, instantiateType), type.aliasSymbol, mapper.targetTypes);
+                    return getIntersectionType(instantiateTypes((<IntersectionType>type).types, mapper), type.aliasSymbol, instantiateTypes(type.aliasTypeArguments, mapper));
                 }
                 if (type.flags & TypeFlags.Index) {
                     return getIndexType(instantiateType((<IndexType>type).type, mapper));
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 5536a818df536..f8c77a821a340 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2940,7 +2940,6 @@ namespace ts {
     export interface TypeMapper {
         (t: TypeParameter): Type;
         mappedTypes?: Type[];       // Types mapped by this mapper
-        targetTypes?: Type[];       // Types substituted for mapped types
         instantiations?: Type[];    // Cache of instantiations created using this type mapper.
         context?: InferenceContext; // The inference context this mapper was created from.
                                     // Only inference mappers have this set (in createInferenceMapper).

From adfa271e4487b0e86932f936b53536262db84c35 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sat, 5 Nov 2016 17:36:13 -0700
Subject: [PATCH 179/224] Add regression test

---
 .../reference/instantiatedTypeAliasDisplay.js | 21 ++++++
 .../instantiatedTypeAliasDisplay.symbols      | 60 +++++++++++++++++
 .../instantiatedTypeAliasDisplay.types        | 66 +++++++++++++++++++
 .../compiler/instantiatedTypeAliasDisplay.ts  | 15 +++++
 4 files changed, 162 insertions(+)
 create mode 100644 tests/baselines/reference/instantiatedTypeAliasDisplay.js
 create mode 100644 tests/baselines/reference/instantiatedTypeAliasDisplay.symbols
 create mode 100644 tests/baselines/reference/instantiatedTypeAliasDisplay.types
 create mode 100644 tests/cases/compiler/instantiatedTypeAliasDisplay.ts

diff --git a/tests/baselines/reference/instantiatedTypeAliasDisplay.js b/tests/baselines/reference/instantiatedTypeAliasDisplay.js
new file mode 100644
index 0000000000000..86b17262e0f06
--- /dev/null
+++ b/tests/baselines/reference/instantiatedTypeAliasDisplay.js
@@ -0,0 +1,21 @@
+//// [instantiatedTypeAliasDisplay.ts]
+// Repros from #12066
+
+interface X<A> {
+    a: A;
+}
+interface Y<B> {
+    b: B;
+}
+type Z<A, B> = X<A> | Y<B>;
+
+declare function f1<A>(): Z<A, number>;
+declare function f2<A, B, C, D, E>(a: A, b: B, c: C, d: D): Z<A, string[]>;
+
+const x1 = f1<string>();  // Z<string, number>
+const x2 = f2({}, {}, {}, {});  // Z<{}, string[]>
+
+//// [instantiatedTypeAliasDisplay.js]
+// Repros from #12066
+var x1 = f1(); // Z<string, number>
+var x2 = f2({}, {}, {}, {}); // Z<{}, string[]>
diff --git a/tests/baselines/reference/instantiatedTypeAliasDisplay.symbols b/tests/baselines/reference/instantiatedTypeAliasDisplay.symbols
new file mode 100644
index 0000000000000..3c6f7d2b725c7
--- /dev/null
+++ b/tests/baselines/reference/instantiatedTypeAliasDisplay.symbols
@@ -0,0 +1,60 @@
+=== tests/cases/compiler/instantiatedTypeAliasDisplay.ts ===
+// Repros from #12066
+
+interface X<A> {
+>X : Symbol(X, Decl(instantiatedTypeAliasDisplay.ts, 0, 0))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 2, 12))
+
+    a: A;
+>a : Symbol(X.a, Decl(instantiatedTypeAliasDisplay.ts, 2, 16))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 2, 12))
+}
+interface Y<B> {
+>Y : Symbol(Y, Decl(instantiatedTypeAliasDisplay.ts, 4, 1))
+>B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 5, 12))
+
+    b: B;
+>b : Symbol(Y.b, Decl(instantiatedTypeAliasDisplay.ts, 5, 16))
+>B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 5, 12))
+}
+type Z<A, B> = X<A> | Y<B>;
+>Z : Symbol(Z, Decl(instantiatedTypeAliasDisplay.ts, 7, 1))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 8, 7))
+>B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 8, 9))
+>X : Symbol(X, Decl(instantiatedTypeAliasDisplay.ts, 0, 0))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 8, 7))
+>Y : Symbol(Y, Decl(instantiatedTypeAliasDisplay.ts, 4, 1))
+>B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 8, 9))
+
+declare function f1<A>(): Z<A, number>;
+>f1 : Symbol(f1, Decl(instantiatedTypeAliasDisplay.ts, 8, 27))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 10, 20))
+>Z : Symbol(Z, Decl(instantiatedTypeAliasDisplay.ts, 7, 1))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 10, 20))
+
+declare function f2<A, B, C, D, E>(a: A, b: B, c: C, d: D): Z<A, string[]>;
+>f2 : Symbol(f2, Decl(instantiatedTypeAliasDisplay.ts, 10, 39))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 11, 20))
+>B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 11, 22))
+>C : Symbol(C, Decl(instantiatedTypeAliasDisplay.ts, 11, 25))
+>D : Symbol(D, Decl(instantiatedTypeAliasDisplay.ts, 11, 28))
+>E : Symbol(E, Decl(instantiatedTypeAliasDisplay.ts, 11, 31))
+>a : Symbol(a, Decl(instantiatedTypeAliasDisplay.ts, 11, 35))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 11, 20))
+>b : Symbol(b, Decl(instantiatedTypeAliasDisplay.ts, 11, 40))
+>B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 11, 22))
+>c : Symbol(c, Decl(instantiatedTypeAliasDisplay.ts, 11, 46))
+>C : Symbol(C, Decl(instantiatedTypeAliasDisplay.ts, 11, 25))
+>d : Symbol(d, Decl(instantiatedTypeAliasDisplay.ts, 11, 52))
+>D : Symbol(D, Decl(instantiatedTypeAliasDisplay.ts, 11, 28))
+>Z : Symbol(Z, Decl(instantiatedTypeAliasDisplay.ts, 7, 1))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 11, 20))
+
+const x1 = f1<string>();  // Z<string, number>
+>x1 : Symbol(x1, Decl(instantiatedTypeAliasDisplay.ts, 13, 5))
+>f1 : Symbol(f1, Decl(instantiatedTypeAliasDisplay.ts, 8, 27))
+
+const x2 = f2({}, {}, {}, {});  // Z<{}, string[]>
+>x2 : Symbol(x2, Decl(instantiatedTypeAliasDisplay.ts, 14, 5))
+>f2 : Symbol(f2, Decl(instantiatedTypeAliasDisplay.ts, 10, 39))
+
diff --git a/tests/baselines/reference/instantiatedTypeAliasDisplay.types b/tests/baselines/reference/instantiatedTypeAliasDisplay.types
new file mode 100644
index 0000000000000..44885777e7483
--- /dev/null
+++ b/tests/baselines/reference/instantiatedTypeAliasDisplay.types
@@ -0,0 +1,66 @@
+=== tests/cases/compiler/instantiatedTypeAliasDisplay.ts ===
+// Repros from #12066
+
+interface X<A> {
+>X : X<A>
+>A : A
+
+    a: A;
+>a : A
+>A : A
+}
+interface Y<B> {
+>Y : Y<B>
+>B : B
+
+    b: B;
+>b : B
+>B : B
+}
+type Z<A, B> = X<A> | Y<B>;
+>Z : Z<A, B>
+>A : A
+>B : B
+>X : X<A>
+>A : A
+>Y : Y<B>
+>B : B
+
+declare function f1<A>(): Z<A, number>;
+>f1 : <A>() => Z<A, number>
+>A : A
+>Z : Z<A, B>
+>A : A
+
+declare function f2<A, B, C, D, E>(a: A, b: B, c: C, d: D): Z<A, string[]>;
+>f2 : <A, B, C, D, E>(a: A, b: B, c: C, d: D) => Z<A, string[]>
+>A : A
+>B : B
+>C : C
+>D : D
+>E : E
+>a : A
+>A : A
+>b : B
+>B : B
+>c : C
+>C : C
+>d : D
+>D : D
+>Z : Z<A, B>
+>A : A
+
+const x1 = f1<string>();  // Z<string, number>
+>x1 : Z<string, number>
+>f1<string>() : Z<string, number>
+>f1 : <A>() => Z<A, number>
+
+const x2 = f2({}, {}, {}, {});  // Z<{}, string[]>
+>x2 : Z<{}, string[]>
+>f2({}, {}, {}, {}) : Z<{}, string[]>
+>f2 : <A, B, C, D, E>(a: A, b: B, c: C, d: D) => Z<A, string[]>
+>{} : {}
+>{} : {}
+>{} : {}
+>{} : {}
+
diff --git a/tests/cases/compiler/instantiatedTypeAliasDisplay.ts b/tests/cases/compiler/instantiatedTypeAliasDisplay.ts
new file mode 100644
index 0000000000000..d2abaaf8afe96
--- /dev/null
+++ b/tests/cases/compiler/instantiatedTypeAliasDisplay.ts
@@ -0,0 +1,15 @@
+// Repros from #12066
+
+interface X<A> {
+    a: A;
+}
+interface Y<B> {
+    b: B;
+}
+type Z<A, B> = X<A> | Y<B>;
+
+declare function f1<A>(): Z<A, number>;
+declare function f2<A, B, C, D, E>(a: A, b: B, c: C, d: D): Z<A, string[]>;
+
+const x1 = f1<string>();  // Z<string, number>
+const x2 = f2({}, {}, {}, {});  // Z<{}, string[]>
\ No newline at end of file

From 2bf4bad0e16a3e3d4546afe47d8ef4fb837778f4 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sun, 6 Nov 2016 16:00:41 -0800
Subject: [PATCH 180/224] Revert incorrect logic from #11392

---
 src/compiler/checker.ts | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index d0028896baade..1a93909834b93 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2229,14 +2229,8 @@ namespace ts {
                         // The specified symbol flags need to be reinterpreted as type flags
                         buildSymbolDisplay(type.symbol, writer, enclosingDeclaration, SymbolFlags.Type, SymbolFormatFlags.None, nextFlags);
                     }
-                    else if (!(flags & TypeFormatFlags.InTypeAlias) && ((getObjectFlags(type) & ObjectFlags.Anonymous && !(<AnonymousType>type).target) || type.flags & TypeFlags.UnionOrIntersection) && type.aliasSymbol &&
+                    else if (!(flags & TypeFormatFlags.InTypeAlias) && (getObjectFlags(type) & ObjectFlags.Anonymous || type.flags & TypeFlags.UnionOrIntersection) && type.aliasSymbol &&
                         isSymbolAccessible(type.aliasSymbol, enclosingDeclaration, SymbolFlags.Type, /*shouldComputeAliasesToMakeVisible*/ false).accessibility === SymbolAccessibility.Accessible) {
-                        // We emit inferred type as type-alias at the current localtion if all the following is true
-                        //      the input type is has alias symbol that is accessible
-                        //      the input type is a union, intersection or anonymous type that is fully instantiated (if not we want to keep dive into)
-                        //          e.g.: export type Bar<X, Y> = () => [X, Y];
-                        //                export type Foo<Y> = Bar<any, Y>;
-                        //                export const y = (x: Foo<string>) => 1  // we want to emit as ...x: () => [any, string])
                         const typeArguments = type.aliasTypeArguments;
                         writeSymbolTypeReference(type.aliasSymbol, typeArguments, 0, typeArguments ? typeArguments.length : 0, nextFlags);
                     }

From cc9daca38d06719612803e90bdf8ca4fcb706b67 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sun, 6 Nov 2016 16:02:32 -0800
Subject: [PATCH 181/224] Accept new baselines

---
 .../declarationEmitTypeAliasWithTypeParameters1.js     |  2 +-
 .../declarationEmitTypeAliasWithTypeParameters1.types  | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters1.js b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters1.js
index c41c469039169..6079de359643c 100644
--- a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters1.js
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters1.js
@@ -12,4 +12,4 @@ exports.y = function (x) { return 1; };
 //// [declarationEmitTypeAliasWithTypeParameters1.d.ts]
 export declare type Bar<X, Y> = () => [X, Y];
 export declare type Foo<Y> = Bar<any, Y>;
-export declare const y: (x: () => [any, string]) => number;
+export declare const y: (x: Bar<any, string>) => number;
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters1.types b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters1.types
index 3ff9f9bde1df2..a8b0f146f8ea0 100644
--- a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters1.types
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters1.types
@@ -8,15 +8,15 @@ export type Bar<X, Y> = () => [X, Y];
 >Y : Y
 
 export type Foo<Y> = Bar<any, Y>;
->Foo : () => [any, Y]
+>Foo : Bar<any, Y>
 >Y : Y
 >Bar : Bar<X, Y>
 >Y : Y
 
 export const y = (x: Foo<string>) => 1
->y : (x: () => [any, string]) => number
->(x: Foo<string>) => 1 : (x: () => [any, string]) => number
->x : () => [any, string]
->Foo : () => [any, Y]
+>y : (x: Bar<any, string>) => number
+>(x: Foo<string>) => 1 : (x: Bar<any, string>) => number
+>x : Bar<any, string>
+>Foo : Bar<any, Y>
 >1 : 1
 

From a84c7aeea4f0109af303dfad05232011abfca212 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 7 Nov 2016 08:36:03 -0800
Subject: [PATCH 182/224] Rename SpreadElementExpression -> SpreadAssignment

and SpreadExpression (formerly SpreadElementExpression) -> SpreadElement
---
 src/compiler/binder.ts                     | 14 +++++-----
 src/compiler/checker.ts                    | 30 +++++++++++-----------
 src/compiler/emitter.ts                    |  6 ++---
 src/compiler/factory.ts                    |  4 +--
 src/compiler/parser.ts                     | 16 ++++++------
 src/compiler/transformers/destructuring.ts |  4 +--
 src/compiler/transformers/es2015.ts        |  6 ++---
 src/compiler/transformers/esnext.ts        |  4 +--
 src/compiler/types.ts                      | 16 +++++-------
 src/compiler/utilities.ts                  | 14 +++++-----
 src/compiler/visitor.ts                    | 10 ++++----
 src/services/breakpoints.ts                |  2 +-
 src/services/utilities.ts                  |  4 +--
 13 files changed, 64 insertions(+), 66 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index b0c456a677068..902d20b0cfd3a 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -1138,8 +1138,8 @@ namespace ts {
             }
             else if (node.kind === SyntaxKind.ArrayLiteralExpression) {
                 for (const e of (<ArrayLiteralExpression>node).elements) {
-                    if (e.kind === SyntaxKind.SpreadExpression) {
-                        bindAssignmentTargetFlow((<SpreadExpression>e).expression);
+                    if (e.kind === SyntaxKind.SpreadElement) {
+                        bindAssignmentTargetFlow((<SpreadElement>e).expression);
                     }
                     else {
                         bindDestructuringTargetFlow(e);
@@ -1154,8 +1154,8 @@ namespace ts {
                     else if (p.kind === SyntaxKind.ShorthandPropertyAssignment) {
                         bindAssignmentTargetFlow((<ShorthandPropertyAssignment>p).name);
                     }
-                    else if (p.kind === SyntaxKind.SpreadElementExpression) {
-                        bindAssignmentTargetFlow((<SpreadElementExpression>p).expression);
+                    else if (p.kind === SyntaxKind.SpreadAssignment) {
+                        bindAssignmentTargetFlow((<SpreadAssignment>p).expression);
                     }
                 }
             }
@@ -1929,7 +1929,7 @@ namespace ts {
                 case SyntaxKind.EnumMember:
                     return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.EnumMember, SymbolFlags.EnumMemberExcludes);
 
-                case SyntaxKind.SpreadElementExpression:
+                case SyntaxKind.SpreadAssignment:
                 case SyntaxKind.JsxSpreadAttribute:
                     emitFlags |= NodeFlags.HasSpreadAttribute;
                     return;
@@ -3127,8 +3127,8 @@ namespace ts {
                 }
                 break;
 
-            case SyntaxKind.SpreadExpression:
-            case SyntaxKind.SpreadElementExpression:
+            case SyntaxKind.SpreadElement:
+            case SyntaxKind.SpreadAssignment:
                 // This node is ES6 or ES future syntax, but is handled by a containing node.
                 transformFlags |= TransformFlags.ContainsSpreadExpression;
                 break;
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 20e90f4db2546..09172d02ad7e7 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -8640,7 +8640,7 @@ namespace ts {
             return getTypeOfDestructuredArrayElement(getAssignedType(node), indexOf(node.elements, element));
         }
 
-        function getAssignedTypeOfSpreadExpression(node: SpreadExpression): Type {
+        function getAssignedTypeOfSpreadExpression(node: SpreadElement): Type {
             return getTypeOfDestructuredSpreadExpression(getAssignedType(<ArrayLiteralExpression>node.parent));
         }
 
@@ -8665,8 +8665,8 @@ namespace ts {
                     return undefinedType;
                 case SyntaxKind.ArrayLiteralExpression:
                     return getAssignedTypeOfArrayLiteralElement(<ArrayLiteralExpression>parent, node);
-                case SyntaxKind.SpreadExpression:
-                    return getAssignedTypeOfSpreadExpression(<SpreadExpression>parent);
+                case SyntaxKind.SpreadElement:
+                    return getAssignedTypeOfSpreadExpression(<SpreadElement>parent);
                 case SyntaxKind.PropertyAssignment:
                     return getAssignedTypeOfPropertyAssignment(<PropertyAssignment>parent);
                 case SyntaxKind.ShorthandPropertyAssignment:
@@ -10697,7 +10697,7 @@ namespace ts {
             return mapper && mapper.context;
         }
 
-        function checkSpreadExpression(node: SpreadExpression, contextualMapper?: TypeMapper): Type {
+        function checkSpreadExpression(node: SpreadElement, contextualMapper?: TypeMapper): Type {
             // It is usually not safe to call checkExpressionCached if we can be contextually typing.
             // You can tell that we are contextually typing because of the contextualMapper parameter.
             // While it is true that a spread element can have a contextual type, it does not do anything
@@ -10719,7 +10719,7 @@ namespace ts {
             const elementTypes: Type[] = [];
             const inDestructuringPattern = isAssignmentTarget(node);
             for (const e of elements) {
-                if (inDestructuringPattern && e.kind === SyntaxKind.SpreadExpression) {
+                if (inDestructuringPattern && e.kind === SyntaxKind.SpreadElement) {
                     // Given the following situation:
                     //    var c: {};
                     //    [...c] = ["", 0];
@@ -10732,7 +10732,7 @@ namespace ts {
                     // get the contextual element type from it. So we do something similar to
                     // getContextualTypeForElementExpression, which will crucially not error
                     // if there is no index type / iterated type.
-                    const restArrayType = checkExpression((<SpreadExpression>e).expression, contextualMapper);
+                    const restArrayType = checkExpression((<SpreadElement>e).expression, contextualMapper);
                     const restElementType = getIndexTypeOfType(restArrayType, IndexKind.Number) ||
                         (languageVersion >= ScriptTarget.ES2015 ? getElementTypeOfIterable(restArrayType, /*errorNode*/ undefined) : undefined);
                     if (restElementType) {
@@ -10743,7 +10743,7 @@ namespace ts {
                     const type = checkExpressionForMutableLocation(e, contextualMapper);
                     elementTypes.push(type);
                 }
-                hasSpreadElement = hasSpreadElement || e.kind === SyntaxKind.SpreadExpression;
+                hasSpreadElement = hasSpreadElement || e.kind === SyntaxKind.SpreadElement;
             }
             if (!hasSpreadElement) {
                 // If array literal is actually a destructuring pattern, mark it as an implied type. We do this such
@@ -10927,7 +10927,7 @@ namespace ts {
                     prop.target = member;
                     member = prop;
                 }
-                else if (memberDecl.kind === SyntaxKind.SpreadElementExpression) {
+                else if (memberDecl.kind === SyntaxKind.SpreadAssignment) {
                     if (propertiesArray.length > 0) {
                         spread = getSpreadType(spread, createObjectLiteralType(), node.symbol);
                         propertiesArray = [];
@@ -10936,7 +10936,7 @@ namespace ts {
                         hasComputedNumberProperty = false;
                         typeFlags = 0;
                     }
-                    const type = checkExpression((memberDecl as SpreadElementExpression).expression);
+                    const type = checkExpression((memberDecl as SpreadAssignment).expression);
                     if (!(type.flags & (TypeFlags.Object | TypeFlags.Any))) {
                         error(memberDecl, Diagnostics.Spread_types_may_only_be_created_from_object_types);
                         return unknownType;
@@ -11905,7 +11905,7 @@ namespace ts {
         function getSpreadArgumentIndex(args: Expression[]): number {
             for (let i = 0; i < args.length; i++) {
                 const arg = args[i];
-                if (arg && arg.kind === SyntaxKind.SpreadExpression) {
+                if (arg && arg.kind === SyntaxKind.SpreadElement) {
                     return i;
                 }
             }
@@ -13893,7 +13893,7 @@ namespace ts {
             const elements = node.elements;
             const element = elements[elementIndex];
             if (element.kind !== SyntaxKind.OmittedExpression) {
-                if (element.kind !== SyntaxKind.SpreadExpression) {
+                if (element.kind !== SyntaxKind.SpreadElement) {
                     const propName = "" + elementIndex;
                     const type = isTypeAny(sourceType)
                         ? sourceType
@@ -13920,7 +13920,7 @@ namespace ts {
                         error(element, Diagnostics.A_rest_element_must_be_last_in_an_array_destructuring_pattern);
                     }
                     else {
-                        const restExpression = (<SpreadExpression>element).expression;
+                        const restExpression = (<SpreadElement>element).expression;
                         if (restExpression.kind === SyntaxKind.BinaryExpression && (<BinaryExpression>restExpression).operatorToken.kind === SyntaxKind.EqualsToken) {
                             error((<BinaryExpression>restExpression).operatorToken, Diagnostics.A_rest_element_cannot_have_an_initializer);
                         }
@@ -14553,8 +14553,8 @@ namespace ts {
                     return checkBinaryExpression(<BinaryExpression>node, contextualMapper);
                 case SyntaxKind.ConditionalExpression:
                     return checkConditionalExpression(<ConditionalExpression>node, contextualMapper);
-                case SyntaxKind.SpreadExpression:
-                    return checkSpreadExpression(<SpreadExpression>node, contextualMapper);
+                case SyntaxKind.SpreadElement:
+                    return checkSpreadExpression(<SpreadElement>node, contextualMapper);
                 case SyntaxKind.OmittedExpression:
                     return undefinedWideningType;
                 case SyntaxKind.YieldExpression:
@@ -20511,7 +20511,7 @@ namespace ts {
             const GetOrSetAccessor = GetAccessor | SetAccessor;
 
             for (const prop of node.properties) {
-                if (prop.kind === SyntaxKind.SpreadElementExpression) {
+                if (prop.kind === SyntaxKind.SpreadAssignment) {
                     continue;
                 }
                 const name = prop.name;
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 0ee598c507aed..6d4688ac004b4 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -822,8 +822,8 @@ const _super = (function (geti, seti) {
                     return emitTemplateExpression(<TemplateExpression>node);
                 case SyntaxKind.YieldExpression:
                     return emitYieldExpression(<YieldExpression>node);
-                case SyntaxKind.SpreadExpression:
-                    return emitSpreadExpression(<SpreadExpression>node);
+                case SyntaxKind.SpreadElement:
+                    return emitSpreadExpression(<SpreadElement>node);
                 case SyntaxKind.ClassExpression:
                     return emitClassExpression(<ClassExpression>node);
                 case SyntaxKind.OmittedExpression:
@@ -1374,7 +1374,7 @@ const _super = (function (geti, seti) {
             emitExpressionWithPrefix(" ", node.expression);
         }
 
-        function emitSpreadExpression(node: SpreadExpression) {
+        function emitSpreadExpression(node: SpreadElement) {
             write("...");
             emitExpression(node.expression);
         }
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index c7fe7d7057499..536ee4cb4b4bf 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -692,12 +692,12 @@ namespace ts {
     }
 
     export function createSpread(expression: Expression, location?: TextRange) {
-        const node = <SpreadExpression>createNode(SyntaxKind.SpreadExpression, location);
+        const node = <SpreadElement>createNode(SyntaxKind.SpreadElement, location);
         node.expression = parenthesizeExpressionForList(expression);
         return node;
     }
 
-    export function updateSpread(node: SpreadExpression, expression: Expression) {
+    export function updateSpread(node: SpreadElement, expression: Expression) {
         if (node.expression !== expression) {
             return updateNode(createSpread(expression, node), node);
         }
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 464f6ca01d802..9e0a5b4cd3379 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -74,8 +74,8 @@ namespace ts {
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).questionToken) ||
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).equalsToken) ||
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).objectAssignmentInitializer);
-            case SyntaxKind.SpreadElementExpression:
-                return visitNode(cbNode, (<SpreadElementExpression>node).expression);
+            case SyntaxKind.SpreadAssignment:
+                return visitNode(cbNode, (<SpreadAssignment>node).expression);
             case SyntaxKind.Parameter:
             case SyntaxKind.PropertyDeclaration:
             case SyntaxKind.PropertySignature:
@@ -199,8 +199,8 @@ namespace ts {
                     visitNode(cbNode, (<ConditionalExpression>node).whenTrue) ||
                     visitNode(cbNode, (<ConditionalExpression>node).colonToken) ||
                     visitNode(cbNode, (<ConditionalExpression>node).whenFalse);
-            case SyntaxKind.SpreadExpression:
-                return visitNode(cbNode, (<SpreadExpression>node).expression);
+            case SyntaxKind.SpreadElement:
+                return visitNode(cbNode, (<SpreadElement>node).expression);
             case SyntaxKind.Block:
             case SyntaxKind.ModuleBlock:
                 return visitNodes(cbNodes, (<Block>node).statements);
@@ -4123,15 +4123,15 @@ namespace ts {
             return finishNode(node);
         }
 
-        function parseSpreadExpression(): Expression {
-            const node = <SpreadExpression>createNode(SyntaxKind.SpreadExpression);
+        function parseSpreadElement(): Expression {
+            const node = <SpreadElement>createNode(SyntaxKind.SpreadElement);
             parseExpected(SyntaxKind.DotDotDotToken);
             node.expression = parseAssignmentExpressionOrHigher();
             return finishNode(node);
         }
 
         function parseArgumentOrArrayLiteralElement(): Expression {
-            return token() === SyntaxKind.DotDotDotToken ? parseSpreadExpression() :
+            return token() === SyntaxKind.DotDotDotToken ? parseSpreadElement() :
                 token() === SyntaxKind.CommaToken ? <Expression>createNode(SyntaxKind.OmittedExpression) :
                     parseAssignmentExpressionOrHigher();
         }
@@ -4166,7 +4166,7 @@ namespace ts {
             const fullStart = scanner.getStartPos();
             const dotDotDotToken = parseOptionalToken(SyntaxKind.DotDotDotToken);
             if (dotDotDotToken) {
-                const spreadElement = <SpreadElementExpression>createNode(SyntaxKind.SpreadElementExpression, fullStart);
+                const spreadElement = <SpreadAssignment>createNode(SyntaxKind.SpreadAssignment, fullStart);
                 spreadElement.expression = parseAssignmentExpressionOrHigher();
                 return addJSDocComment(finishNode(spreadElement));
             }
diff --git a/src/compiler/transformers/destructuring.ts b/src/compiler/transformers/destructuring.ts
index 89beade577d80..8994a28a97ed0 100644
--- a/src/compiler/transformers/destructuring.ts
+++ b/src/compiler/transformers/destructuring.ts
@@ -308,11 +308,11 @@ namespace ts {
                 const e = elements[i];
                 if (e.kind !== SyntaxKind.OmittedExpression) {
                     // Assignment for target = value.propName should highligh whole property, hence use e as source map node
-                    if (e.kind !== SyntaxKind.SpreadExpression) {
+                    if (e.kind !== SyntaxKind.SpreadElement) {
                         emitDestructuringAssignment(e, createElementAccess(value, createLiteral(i)), e);
                     }
                     else if (i === numElements - 1) {
-                        emitDestructuringAssignment((<SpreadExpression>e).expression, createArraySlice(value, i), e);
+                        emitDestructuringAssignment((<SpreadElement>e).expression, createArraySlice(value, i), e);
                     }
                 }
             }
diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
index e262b413b4c72..6869b2b5eb727 100644
--- a/src/compiler/transformers/es2015.ts
+++ b/src/compiler/transformers/es2015.ts
@@ -2890,7 +2890,7 @@ namespace ts {
          *
          * @param node A SpreadExpression node.
          */
-        function visitExpressionOfSpread(node: SpreadExpression) {
+        function visitExpressionOfSpread(node: SpreadElement) {
             return visitNode(node.expression, visitor, isExpression);
         }
 
@@ -3266,11 +3266,11 @@ namespace ts {
             }
 
             const callArgument = singleOrUndefined((<CallExpression>statementExpression).arguments);
-            if (!callArgument || !nodeIsSynthesized(callArgument) || callArgument.kind !== SyntaxKind.SpreadExpression) {
+            if (!callArgument || !nodeIsSynthesized(callArgument) || callArgument.kind !== SyntaxKind.SpreadElement) {
                 return false;
             }
 
-            const expression = (<SpreadExpression>callArgument).expression;
+            const expression = (<SpreadElement>callArgument).expression;
             return isIdentifier(expression) && expression === parameter.name;
         }
     }
diff --git a/src/compiler/transformers/esnext.ts b/src/compiler/transformers/esnext.ts
index 1a8ed7da5eb4a..38ff99fd78a7e 100644
--- a/src/compiler/transformers/esnext.ts
+++ b/src/compiler/transformers/esnext.ts
@@ -36,12 +36,12 @@ namespace ts {
             let chunkObject: (ShorthandPropertyAssignment | PropertyAssignment)[];
             const objects: Expression[] = [];
             for (const e of elements) {
-                if (e.kind === SyntaxKind.SpreadElementExpression) {
+                if (e.kind === SyntaxKind.SpreadAssignment) {
                     if (chunkObject) {
                         objects.push(createObjectLiteral(chunkObject));
                         chunkObject = undefined;
                     }
-                    const target = (e as SpreadElementExpression).expression;
+                    const target = (e as SpreadAssignment).expression;
                     objects.push(visitNode(target, visitor, isExpression));
                 }
                 else {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index d3b4cb3b6e7df..3f40272bd4cc4 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -246,7 +246,7 @@ namespace ts {
         ConditionalExpression,
         TemplateExpression,
         YieldExpression,
-        SpreadExpression,
+        SpreadElement,
         ClassExpression,
         OmittedExpression,
         ExpressionWithTypeArguments,
@@ -320,7 +320,7 @@ namespace ts {
         // Property assignments
         PropertyAssignment,
         ShorthandPropertyAssignment,
-        SpreadElementExpression,
+        SpreadAssignment,
 
         // Enum
         EnumMember,
@@ -662,7 +662,6 @@ namespace ts {
         initializer?: Expression;           // Optional initializer
     }
 
-    // @kind(SyntaxKind.PropertyDeclaration)
     export interface PropertyDeclaration extends ClassElement {
         kind: SyntaxKind.PropertyDeclaration;
         questionToken?: QuestionToken;               // Present for use with reporting a grammar error
@@ -676,7 +675,7 @@ namespace ts {
         name?: PropertyName;
     }
 
-    export type ObjectLiteralElementLike = PropertyAssignment | ShorthandPropertyAssignment | MethodDeclaration | AccessorDeclaration | SpreadElementExpression;
+    export type ObjectLiteralElementLike = PropertyAssignment | ShorthandPropertyAssignment | MethodDeclaration | AccessorDeclaration | SpreadAssignment;
 
     export interface PropertyAssignment extends ObjectLiteralElement {
         kind: SyntaxKind.PropertyAssignment;
@@ -695,8 +694,8 @@ namespace ts {
         objectAssignmentInitializer?: Expression;
     }
 
-    export interface SpreadElementExpression extends ObjectLiteralElement {
-        kind: SyntaxKind.SpreadElementExpression;
+    export interface SpreadAssignment extends ObjectLiteralElement {
+        kind: SyntaxKind.SpreadAssignment;
         expression: Expression;
     }
 
@@ -1285,9 +1284,8 @@ namespace ts {
         multiLine?: boolean;
     }
 
-    // @kind(SyntaxKind.SpreadExpression)
-    export interface SpreadExpression extends Expression {
-        kind: SyntaxKind.SpreadExpression;
+    export interface SpreadElement extends Expression {
+        kind: SyntaxKind.SpreadElement;
         expression: Expression;
     }
 
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index cd3e6ab9575b5..b668fe6eb1582 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -1179,7 +1179,7 @@ namespace ts {
             case SyntaxKind.PostfixUnaryExpression:
             case SyntaxKind.BinaryExpression:
             case SyntaxKind.ConditionalExpression:
-            case SyntaxKind.SpreadExpression:
+            case SyntaxKind.SpreadElement:
             case SyntaxKind.TemplateExpression:
             case SyntaxKind.NoSubstitutionTemplateLiteral:
             case SyntaxKind.OmittedExpression:
@@ -1641,7 +1641,7 @@ namespace ts {
                     return (<ForInStatement | ForOfStatement>parent).initializer === node ? AssignmentKind.Definite : AssignmentKind.None;
                 case SyntaxKind.ParenthesizedExpression:
                 case SyntaxKind.ArrayLiteralExpression:
-                case SyntaxKind.SpreadExpression:
+                case SyntaxKind.SpreadElement:
                     node = parent;
                     break;
                 case SyntaxKind.ShorthandPropertyAssignment:
@@ -2226,7 +2226,7 @@ namespace ts {
             case SyntaxKind.YieldExpression:
                 return 2;
 
-            case SyntaxKind.SpreadExpression:
+            case SyntaxKind.SpreadElement:
                 return 1;
 
             default:
@@ -3862,7 +3862,7 @@ namespace ts {
         const kind = node.kind;
         return kind === SyntaxKind.PropertyAssignment
             || kind === SyntaxKind.ShorthandPropertyAssignment
-            || kind === SyntaxKind.SpreadElementExpression
+            || kind === SyntaxKind.SpreadAssignment
             || kind === SyntaxKind.MethodDeclaration
             || kind === SyntaxKind.GetAccessor
             || kind === SyntaxKind.SetAccessor
@@ -3950,8 +3950,8 @@ namespace ts {
             || kind === SyntaxKind.NoSubstitutionTemplateLiteral;
     }
 
-    export function isSpreadExpression(node: Node): node is SpreadExpression {
-        return node.kind === SyntaxKind.SpreadExpression;
+    export function isSpreadExpression(node: Node): node is SpreadElement {
+        return node.kind === SyntaxKind.SpreadElement;
     }
 
     export function isExpressionWithTypeArguments(node: Node): node is ExpressionWithTypeArguments {
@@ -4009,7 +4009,7 @@ namespace ts {
             || kind === SyntaxKind.YieldExpression
             || kind === SyntaxKind.ArrowFunction
             || kind === SyntaxKind.BinaryExpression
-            || kind === SyntaxKind.SpreadExpression
+            || kind === SyntaxKind.SpreadElement
             || kind === SyntaxKind.AsExpression
             || kind === SyntaxKind.OmittedExpression
             || isUnaryExpressionKind(kind);
diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index 4bcc697a99911..0fb0b182345e6 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -267,9 +267,9 @@ namespace ts {
             case SyntaxKind.VoidExpression:
             case SyntaxKind.AwaitExpression:
             case SyntaxKind.YieldExpression:
-            case SyntaxKind.SpreadExpression:
+            case SyntaxKind.SpreadElement:
             case SyntaxKind.NonNullExpression:
-                result = reduceNode((<ParenthesizedExpression | DeleteExpression | TypeOfExpression | VoidExpression | AwaitExpression | YieldExpression | SpreadExpression | NonNullExpression>node).expression, f, result);
+                result = reduceNode((<ParenthesizedExpression | DeleteExpression | TypeOfExpression | VoidExpression | AwaitExpression | YieldExpression | SpreadElement | NonNullExpression>node).expression, f, result);
                 break;
 
             case SyntaxKind.PrefixUnaryExpression:
@@ -870,9 +870,9 @@ namespace ts {
                 return updateYield(<YieldExpression>node,
                     visitNode((<YieldExpression>node).expression, visitor, isExpression));
 
-            case SyntaxKind.SpreadExpression:
-                return updateSpread(<SpreadExpression>node,
-                    visitNode((<SpreadExpression>node).expression, visitor, isExpression));
+            case SyntaxKind.SpreadElement:
+                return updateSpread(<SpreadElement>node,
+                    visitNode((<SpreadElement>node).expression, visitor, isExpression));
 
             case SyntaxKind.ClassExpression:
                 return updateClassExpression(<ClassExpression>node,
diff --git a/src/services/breakpoints.ts b/src/services/breakpoints.ts
index f1cc233e67680..6825ccb6371ff 100644
--- a/src/services/breakpoints.ts
+++ b/src/services/breakpoints.ts
@@ -264,7 +264,7 @@ namespace ts.BreakpointResolver {
                         // a or ...c  or d: x from
                         // [a, b, ...c] or { a, b } or { d: x } from destructuring pattern
                         if ((node.kind === SyntaxKind.Identifier ||
-                            node.kind == SyntaxKind.SpreadExpression ||
+                            node.kind == SyntaxKind.SpreadElement ||
                             node.kind === SyntaxKind.PropertyAssignment ||
                             node.kind === SyntaxKind.ShorthandPropertyAssignment) &&
                             isArrayLiteralOrObjectLiteralDestructuringPattern(node.parent)) {
diff --git a/src/services/utilities.ts b/src/services/utilities.ts
index 2db495a51f9e8..cfb6aae010b63 100644
--- a/src/services/utilities.ts
+++ b/src/services/utilities.ts
@@ -530,8 +530,8 @@ namespace ts {
             case SyntaxKind.DeleteExpression:
             case SyntaxKind.VoidExpression:
             case SyntaxKind.YieldExpression:
-            case SyntaxKind.SpreadExpression:
-                const unaryWordExpression = n as (TypeOfExpression | DeleteExpression | VoidExpression | YieldExpression | SpreadExpression);
+            case SyntaxKind.SpreadElement:
+                const unaryWordExpression = n as (TypeOfExpression | DeleteExpression | VoidExpression | YieldExpression | SpreadElement);
                 return isCompletedNode(unaryWordExpression.expression, sourceFile);
 
             case SyntaxKind.TaggedTemplateExpression:

From 6a82ae4cbb209d6f3fdad74cdf6146747ed33449 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 7 Nov 2016 09:04:00 -0800
Subject: [PATCH 183/224] Add SpreadAssignment to visitors

1. visitNode
2. reduceNode
3. emit

This fixes an emit bug for setters.
---
 src/compiler/emitter.ts                         |  9 +++++++++
 src/compiler/factory.ts                         | 17 +++++++++++++++--
 src/compiler/visitor.ts                         | 10 +++++++++-
 .../baselines/reference/objectSpreadNegative.js |  2 +-
 4 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 6d4688ac004b4..b0413b2578e8f 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -732,6 +732,8 @@ const _super = (function (geti, seti) {
                     return emitPropertyAssignment(<PropertyAssignment>node);
                 case SyntaxKind.ShorthandPropertyAssignment:
                     return emitShorthandPropertyAssignment(<ShorthandPropertyAssignment>node);
+                case SyntaxKind.ShorthandPropertyAssignment:
+                    return emitSpreadAssignment(node as SpreadAssignment);
 
                 // Enum
                 case SyntaxKind.EnumMember:
@@ -2102,6 +2104,13 @@ const _super = (function (geti, seti) {
             }
         }
 
+        function emitSpreadAssignment(node: SpreadAssignment) {
+            if (node.expression) {
+                write("...");
+                emitExpression(node.expression);
+            }
+        }
+
         //
         // Enum
         //
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 536ee4cb4b4bf..fd2b7c1ccee34 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -1399,14 +1399,27 @@ namespace ts {
         return node;
     }
 
-    export function updateShorthandPropertyAssignment(node: ShorthandPropertyAssignment, name: Identifier, objectAssignmentInitializer: Expression) {
+    export function createSpreadAssignment(expression: Expression, location?: TextRange) {
+        const node = <SpreadAssignment>createNode(SyntaxKind.SpreadAssignment, location);
+        node.expression = expression !== undefined ? parenthesizeExpressionForList(expression) : undefined;
+        return node;
+    }
+
+   export function updateShorthandPropertyAssignment(node: ShorthandPropertyAssignment, name: Identifier, objectAssignmentInitializer: Expression) {
         if (node.name !== name || node.objectAssignmentInitializer !== objectAssignmentInitializer) {
             return updateNode(createShorthandPropertyAssignment(name, objectAssignmentInitializer, node), node);
         }
         return node;
     }
 
-    // Top-level nodes
+    export function updateSpreadAssignment(node: SpreadAssignment, expression: Expression) {
+        if (node.expression !== expression) {
+            return updateNode(createSpreadAssignment(expression, node), node);
+        }
+        return node;
+    }
+
+   // Top-level nodes
 
     export function updateSourceFileNode(node: SourceFile, statements: Statement[]) {
         if (node.statements !== statements) {
diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index 0fb0b182345e6..db59c30934507 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -510,6 +510,10 @@ namespace ts {
                 result = reduceNode((<ShorthandPropertyAssignment>node).objectAssignmentInitializer, f, result);
                 break;
 
+            case SyntaxKind.SpreadAssignment:
+                result = reduceNode((node as SpreadAssignment).expression, f, result);
+                break;
+
             // Top-level nodes
             case SyntaxKind.SourceFile:
                 result = reduceLeft((<SourceFile>node).statements, f, result);
@@ -1125,7 +1129,11 @@ namespace ts {
                     visitNode((<ShorthandPropertyAssignment>node).name, visitor, isIdentifier),
                     visitNode((<ShorthandPropertyAssignment>node).objectAssignmentInitializer, visitor, isExpression));
 
-            // Top-level nodes
+            case SyntaxKind.SpreadAssignment:
+                return updateSpreadAssignment(node as SpreadAssignment,
+                    visitNode((node as SpreadAssignment).expression, visitor, isExpression));
+
+           // Top-level nodes
             case SyntaxKind.SourceFile:
                 context.startLexicalEnvironment();
                 return updateSourceFileNode(<SourceFile>node,
diff --git a/tests/baselines/reference/objectSpreadNegative.js b/tests/baselines/reference/objectSpreadNegative.js
index 4faacd9744450..6287f4559a79b 100644
--- a/tests/baselines/reference/objectSpreadNegative.js
+++ b/tests/baselines/reference/objectSpreadNegative.js
@@ -123,7 +123,7 @@ spreadStr.charAt(1); // error, no methods either
 var spreadFunc = __assign({}, function () { });
 spreadFunc(); // error, no call signature
 // write-only properties get skipped
-var setterOnly = __assign({ set b(bad: number) { } });
+var setterOnly = __assign({ set b(bad) { } });
 setterOnly.b = 12; // error, 'b' does not exist
 // methods are skipped because they aren't enumerable
 var C = (function () {

From 7b9a42f9958b072f057d42d506b7e082ebf19974 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 7 Nov 2016 09:54:48 -0800
Subject: [PATCH 184/224] Add --target esnext

Currently, this disables the rest and spread transforms. This will
change as proposals enter and leave stage 3.
---
 src/compiler/commandLineParser.ts | 1 +
 src/compiler/emitter.ts           | 7 +++++--
 src/compiler/transformer.ts       | 5 ++++-
 src/compiler/types.ts             | 3 ++-
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 50399fd5c38e7..6e5256bafa4df 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -265,6 +265,7 @@ namespace ts {
                 "es2015": ScriptTarget.ES2015,
                 "es2016": ScriptTarget.ES2016,
                 "es2017": ScriptTarget.ES2017,
+                "esnext": ScriptTarget.ESNext,
             }),
             description: Diagnostics.Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015,
             paramType: Diagnostics.VERSION,
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index b0413b2578e8f..ce37492f66662 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -732,7 +732,7 @@ const _super = (function (geti, seti) {
                     return emitPropertyAssignment(<PropertyAssignment>node);
                 case SyntaxKind.ShorthandPropertyAssignment:
                     return emitShorthandPropertyAssignment(<ShorthandPropertyAssignment>node);
-                case SyntaxKind.ShorthandPropertyAssignment:
+                case SyntaxKind.SpreadAssignment:
                     return emitSpreadAssignment(node as SpreadAssignment);
 
                 // Enum
@@ -2214,7 +2214,10 @@ const _super = (function (geti, seti) {
                 helpersEmitted = true;
             }
 
-            if (compilerOptions.jsx !== JsxEmit.Preserve && !assignEmitted && (node.flags & NodeFlags.HasSpreadAttribute)) {
+            if ((languageVersion < ScriptTarget.ESNext || currentSourceFile.scriptKind === ScriptKind.JSX || currentSourceFile.scriptKind === ScriptKind.TSX) &&
+                compilerOptions.jsx !== JsxEmit.Preserve &&
+                !assignEmitted &&
+                node.flags & NodeFlags.HasSpreadAttribute) {
                 writeLines(assignHelper);
                 assignEmitted = true;
             }
diff --git a/src/compiler/transformer.ts b/src/compiler/transformer.ts
index 069b1e46af56b..b005b1906f696 100644
--- a/src/compiler/transformer.ts
+++ b/src/compiler/transformer.ts
@@ -117,7 +117,10 @@ namespace ts {
             transformers.push(transformJsx);
         }
 
-        transformers.push(transformESNext);
+        if (languageVersion < ScriptTarget.ESNext) {
+            transformers.push(transformESNext);
+        }
+
         if (languageVersion < ScriptTarget.ES2017) {
             transformers.push(transformES2017);
         }
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 3f40272bd4cc4..13b66c1c0aa64 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -3171,7 +3171,8 @@ namespace ts {
         ES2015 = 2,
         ES2016 = 3,
         ES2017 = 4,
-        Latest = ES2017,
+        ESNext = 5,
+        Latest = ESNext,
     }
 
     export const enum LanguageVariant {

From d4a5b0855caf74542903963fc012e75ca7ef3a48 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 7 Nov 2016 09:56:48 -0800
Subject: [PATCH 185/224] Add --target esnext tests and update baselines

---
 src/harness/unittests/commandLineParsing.ts      |  2 +-
 .../unittests/convertCompilerOptionsFromJson.ts  |  2 +-
 .../reference/objectSpreadNoTransform.js         |  8 ++++++++
 .../reference/objectSpreadNoTransform.symbols    | 10 ++++++++++
 .../reference/objectSpreadNoTransform.types      | 16 ++++++++++++++++
 .../types/spread/objectSpreadNoTransform.ts      |  3 +++
 6 files changed, 39 insertions(+), 2 deletions(-)
 create mode 100644 tests/baselines/reference/objectSpreadNoTransform.js
 create mode 100644 tests/baselines/reference/objectSpreadNoTransform.symbols
 create mode 100644 tests/baselines/reference/objectSpreadNoTransform.types
 create mode 100644 tests/cases/conformance/types/spread/objectSpreadNoTransform.ts

diff --git a/src/harness/unittests/commandLineParsing.ts b/src/harness/unittests/commandLineParsing.ts
index c15490738fa87..890f167e2dd2c 100644
--- a/src/harness/unittests/commandLineParsing.ts
+++ b/src/harness/unittests/commandLineParsing.ts
@@ -165,7 +165,7 @@ namespace ts {
                         start: undefined,
                         length: undefined,
                     }, {
-                            messageText: "Argument for '--target' option must be: 'es3', 'es5', 'es6', 'es2015', 'es2016', 'es2017'",
+                            messageText: "Argument for '--target' option must be: 'es3', 'es5', 'es6', 'es2015', 'es2016', 'es2017', 'esnext'",
                             category: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.category,
                             code: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
 
diff --git a/src/harness/unittests/convertCompilerOptionsFromJson.ts b/src/harness/unittests/convertCompilerOptionsFromJson.ts
index 2942675f0ac5e..23c372b531330 100644
--- a/src/harness/unittests/convertCompilerOptionsFromJson.ts
+++ b/src/harness/unittests/convertCompilerOptionsFromJson.ts
@@ -176,7 +176,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--target' option must be: 'es3', 'es5', 'es6', 'es2015', 'es2016', 'es2017'",
+                        messageText: "Argument for '--target' option must be: 'es3', 'es5', 'es6', 'es2015', 'es2016', 'es2017', 'esnext'",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
diff --git a/tests/baselines/reference/objectSpreadNoTransform.js b/tests/baselines/reference/objectSpreadNoTransform.js
new file mode 100644
index 0000000000000..8916c621969ed
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadNoTransform.js
@@ -0,0 +1,8 @@
+//// [objectSpreadNoTransform.ts]
+const y = { a: 'yes', b: 'no' };
+const o = { x: 1, ...y };
+
+
+//// [objectSpreadNoTransform.js]
+const y = { a: 'yes', b: 'no' };
+const o = { x: 1, ...y };
diff --git a/tests/baselines/reference/objectSpreadNoTransform.symbols b/tests/baselines/reference/objectSpreadNoTransform.symbols
new file mode 100644
index 0000000000000..4d77bc848303d
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadNoTransform.symbols
@@ -0,0 +1,10 @@
+=== tests/cases/conformance/types/spread/objectSpreadNoTransform.ts ===
+const y = { a: 'yes', b: 'no' };
+>y : Symbol(y, Decl(objectSpreadNoTransform.ts, 0, 5))
+>a : Symbol(a, Decl(objectSpreadNoTransform.ts, 0, 11))
+>b : Symbol(b, Decl(objectSpreadNoTransform.ts, 0, 21))
+
+const o = { x: 1, ...y };
+>o : Symbol(o, Decl(objectSpreadNoTransform.ts, 1, 5))
+>x : Symbol(x, Decl(objectSpreadNoTransform.ts, 1, 11))
+
diff --git a/tests/baselines/reference/objectSpreadNoTransform.types b/tests/baselines/reference/objectSpreadNoTransform.types
new file mode 100644
index 0000000000000..3a412e2894eea
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadNoTransform.types
@@ -0,0 +1,16 @@
+=== tests/cases/conformance/types/spread/objectSpreadNoTransform.ts ===
+const y = { a: 'yes', b: 'no' };
+>y : { a: string; b: string; }
+>{ a: 'yes', b: 'no' } : { a: string; b: string; }
+>a : string
+>'yes' : "yes"
+>b : string
+>'no' : "no"
+
+const o = { x: 1, ...y };
+>o : { a: string; b: string; x: number; }
+>{ x: 1, ...y } : { a: string; b: string; x: number; }
+>x : number
+>1 : 1
+>y : any
+
diff --git a/tests/cases/conformance/types/spread/objectSpreadNoTransform.ts b/tests/cases/conformance/types/spread/objectSpreadNoTransform.ts
new file mode 100644
index 0000000000000..00039117a20ef
--- /dev/null
+++ b/tests/cases/conformance/types/spread/objectSpreadNoTransform.ts
@@ -0,0 +1,3 @@
+// @target: esnext
+const y = { a: 'yes', b: 'no' };
+const o = { x: 1, ...y };

From 83e95d43f8db0f19d810399d80c85228c612acf3 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 7 Nov 2016 10:58:31 -0800
Subject: [PATCH 186/224] Revert unneeded change and comments per PR

---
 src/compiler/checker.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 09172d02ad7e7..7612bf1dddf19 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4597,7 +4597,7 @@ namespace ts {
                 result.valueDeclaration = declarations[0];
             }
             result.isReadonly = isReadonly;
-            result.type = containingType.flags & TypeFlags.Intersection ? getIntersectionType(propTypes) : getUnionType(propTypes);
+            result.type = containingType.flags & TypeFlags.Union ? getUnionType(propTypes) : getIntersectionType(propTypes);
             return result;
         }
 
@@ -5880,7 +5880,7 @@ namespace ts {
         }
 
         /**
-         * Since the source of spread types are object literals and type literals, which are not binary,
+         * Since the source of spread types are object literals, which are not binary,
          * this function should be called in a left folding style, with left = previous result of getSpreadType
          * and right = the new element to be spread.
          */

From 1866d0580c4801e3d4284e5952026de680643945 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 7 Nov 2016 11:16:54 -0800
Subject: [PATCH 187/224] Rename variable in checkSwitchStatement per PR

---
 src/compiler/checker.ts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 326d84278be24..38d3a97a2874d 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -16906,14 +16906,14 @@ namespace ts {
                     // to or from the type of the 'switch' expression.
                     let caseType = checkExpression(caseClause.expression);
                     const caseIsLiteral = isLiteralType(caseType);
-                    let literalExpressionType = expressionType;
+                    let comparedExpressionType = expressionType;
                     if (!caseIsLiteral || !expressionIsLiteral) {
                         caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
-                        literalExpressionType = getBaseTypeOfLiteralType(expressionType);
+                        comparedExpressionType = getBaseTypeOfLiteralType(expressionType);
                     }
-                    if (!isTypeEqualityComparableTo(literalExpressionType, caseType)) {
+                    if (!isTypeEqualityComparableTo(comparedExpressionType, caseType)) {
                         // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
-                        checkTypeComparableTo(caseType, literalExpressionType, caseClause.expression, /*headMessage*/ undefined);
+                        checkTypeComparableTo(caseType, comparedExpressionType, caseClause.expression, /*headMessage*/ undefined);
                     }
                 }
                 forEach(clause.statements, checkSourceElement);

From 9977936190fd15c1ec4043276ba1f7a8815b3d06 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 7 Nov 2016 11:34:37 -0800
Subject: [PATCH 188/224] Do not emit __rest for --target esnext

---
 src/compiler/emitter.ts                            |  2 +-
 .../baselines/reference/objectSpreadNoTransform.js |  6 ++++++
 .../reference/objectSpreadNoTransform.symbols      | 10 ++++++++++
 .../reference/objectSpreadNoTransform.types        | 14 ++++++++++++++
 .../types/spread/objectSpreadNoTransform.ts        |  3 +++
 5 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index f22f695a3e588..fa0d44a695f54 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -2231,7 +2231,7 @@ const _super = (function (geti, seti) {
                 assignEmitted = true;
             }
 
-            if (!restEmitted && node.flags & NodeFlags.HasRestAttribute) {
+            if (languageVersion < ScriptTarget.ESNext && !restEmitted && node.flags & NodeFlags.HasRestAttribute) {
                 writeLines(restHelper);
                 restEmitted = true;
             }
diff --git a/tests/baselines/reference/objectSpreadNoTransform.js b/tests/baselines/reference/objectSpreadNoTransform.js
index 8916c621969ed..3442d0864092d 100644
--- a/tests/baselines/reference/objectSpreadNoTransform.js
+++ b/tests/baselines/reference/objectSpreadNoTransform.js
@@ -1,8 +1,14 @@
 //// [objectSpreadNoTransform.ts]
 const y = { a: 'yes', b: 'no' };
 const o = { x: 1, ...y };
+var b;
+var rest;
+({ b, ...rest } = o);
 
 
 //// [objectSpreadNoTransform.js]
 const y = { a: 'yes', b: 'no' };
 const o = { x: 1, ...y };
+var b;
+var rest;
+({ b, ...rest } = o);
diff --git a/tests/baselines/reference/objectSpreadNoTransform.symbols b/tests/baselines/reference/objectSpreadNoTransform.symbols
index 4d77bc848303d..d7dac11a53041 100644
--- a/tests/baselines/reference/objectSpreadNoTransform.symbols
+++ b/tests/baselines/reference/objectSpreadNoTransform.symbols
@@ -8,3 +8,13 @@ const o = { x: 1, ...y };
 >o : Symbol(o, Decl(objectSpreadNoTransform.ts, 1, 5))
 >x : Symbol(x, Decl(objectSpreadNoTransform.ts, 1, 11))
 
+var b;
+>b : Symbol(b, Decl(objectSpreadNoTransform.ts, 2, 3))
+
+var rest;
+>rest : Symbol(rest, Decl(objectSpreadNoTransform.ts, 3, 3))
+
+({ b, ...rest } = o);
+>b : Symbol(b, Decl(objectSpreadNoTransform.ts, 4, 2))
+>o : Symbol(o, Decl(objectSpreadNoTransform.ts, 1, 5))
+
diff --git a/tests/baselines/reference/objectSpreadNoTransform.types b/tests/baselines/reference/objectSpreadNoTransform.types
index 3a412e2894eea..0a6c867e8fed4 100644
--- a/tests/baselines/reference/objectSpreadNoTransform.types
+++ b/tests/baselines/reference/objectSpreadNoTransform.types
@@ -14,3 +14,17 @@ const o = { x: 1, ...y };
 >1 : 1
 >y : any
 
+var b;
+>b : any
+
+var rest;
+>rest : any
+
+({ b, ...rest } = o);
+>({ b, ...rest } = o) : { a: string; b: string; x: number; }
+>{ b, ...rest } = o : { a: string; b: string; x: number; }
+>{ b, ...rest } : any
+>b : any
+>rest : any
+>o : { a: string; b: string; x: number; }
+
diff --git a/tests/cases/conformance/types/spread/objectSpreadNoTransform.ts b/tests/cases/conformance/types/spread/objectSpreadNoTransform.ts
index 00039117a20ef..36c75e70887bb 100644
--- a/tests/cases/conformance/types/spread/objectSpreadNoTransform.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadNoTransform.ts
@@ -1,3 +1,6 @@
 // @target: esnext
 const y = { a: 'yes', b: 'no' };
 const o = { x: 1, ...y };
+var b;
+var rest;
+({ b, ...rest } = o);

From d5c67312f619f3283c2c1a448b965d6698da41a5 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Mon, 7 Nov 2016 12:41:22 -0800
Subject: [PATCH 189/224] Add `realpath` implementation for lshost

---
 src/server/lsHost.ts | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/server/lsHost.ts b/src/server/lsHost.ts
index 628de71bb7a91..f1e80d95880e2 100644
--- a/src/server/lsHost.ts
+++ b/src/server/lsHost.ts
@@ -13,6 +13,7 @@ namespace ts.server {
 
         private readonly resolveModuleName: typeof resolveModuleName;
         readonly trace: (s: string) => void;
+        readonly realpath?: (path: string) => string;
 
         constructor(private readonly host: ServerHost, private readonly project: Project, private readonly cancellationToken: HostCancellationToken) {
             this.getCanonicalFileName = ts.createGetCanonicalFileName(this.host.useCaseSensitiveFileNames);
@@ -39,6 +40,10 @@ namespace ts.server {
                 }
                 return primaryResult;
             };
+
+            if (this.host.realpath) {
+                this.realpath = path => this.host.realpath(path);
+            }
         }
 
         public startRecordingFilesWithChangedResolutions() {

From 567f5636e3e4c9bf4790f99fd8bb2e07afcb8561 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 7 Nov 2016 13:02:05 -0800
Subject: [PATCH 190/224] Create spread property types eagerly

This avoids the need for a synthetic symbol and later code called from
getTypeOfSymbol.
---
 src/compiler/checker.ts   | 44 +++++++++++++--------------------------
 src/compiler/types.ts     |  1 -
 src/compiler/utilities.ts |  1 +
 3 files changed, 16 insertions(+), 30 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index b3200ab239bfe..73e4e273d66b0 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -3550,9 +3550,6 @@ namespace ts {
             if (symbol.flags & SymbolFlags.Instantiated) {
                 return getTypeOfInstantiatedSymbol(symbol);
             }
-            if (symbol.flags & SymbolFlags.SyntheticProperty && symbol.syntheticKind === SyntheticSymbolKind.Spread) {
-                return getTypeOfSpreadProperty(symbol);
-            }
             if (symbol.flags & (SymbolFlags.Variable | SymbolFlags.Property)) {
                 return getTypeOfVariableOrParameterOrProperty(symbol);
             }
@@ -3571,14 +3568,6 @@ namespace ts {
             return unknownType;
         }
 
-        function getTypeOfSpreadProperty(symbol: Symbol) {
-            const links = getSymbolLinks(symbol);
-            if (!links.type) {
-                links.type = getUnionType([getTypeOfSymbol(links.leftSpread), getTypeOfSymbol(links.rightSpread)]);
-            }
-            return links.type;
-        }
-
         function getTargetType(type: Type): Type {
             return getObjectFlags(type) & ObjectFlags.Reference ? (<TypeReference>type).target : type;
         }
@@ -4588,7 +4577,6 @@ namespace ts {
                 propTypes.push(type);
             }
             const result = <TransientSymbol>createSymbol(SymbolFlags.Property | SymbolFlags.Transient | SymbolFlags.SyntheticProperty | commonFlags, name);
-            result.syntheticKind = SyntheticSymbolKind.UnionOrIntersection;
             result.containingType = containingType;
             result.hasNonUniformType = hasNonUniformType;
             result.isPartial = isPartial;
@@ -5932,9 +5920,9 @@ namespace ts {
                     const rightProp = members[leftProp.name];
                     if (rightProp.flags & SymbolFlags.Optional) {
                         const declarations: Declaration[] = concatenate(leftProp.declarations, rightProp.declarations);
-                        const flags = SymbolFlags.Property | SymbolFlags.Transient | SymbolFlags.SyntheticProperty | (leftProp.flags & SymbolFlags.Optional);
+                        const flags = SymbolFlags.Property | SymbolFlags.Transient | (leftProp.flags & SymbolFlags.Optional);
                         const result = <TransientSymbol>createSymbol(flags, leftProp.name);
-                        result.syntheticKind = SyntheticSymbolKind.Spread;
+                        result.type = getUnionType([getTypeOfSymbol(leftProp), getTypeOfSymbol(rightProp)]);
                         result.leftSpread = leftProp;
                         result.rightSpread = rightProp;
                         result.declarations = declarations;
@@ -19220,23 +19208,21 @@ namespace ts {
 
         function getRootSymbols(symbol: Symbol): Symbol[] {
             if (symbol.flags & SymbolFlags.SyntheticProperty) {
-                if (symbol.syntheticKind === SyntheticSymbolKind.Spread) {
-                    const links = getSymbolLinks(symbol);
-                    return [links.leftSpread, links.rightSpread];
-                }
-                else {
-                    const symbols: Symbol[] = [];
-                    const name = symbol.name;
-                    forEach(getSymbolLinks(symbol).containingType.types, t => {
-                        const symbol = getPropertyOfType(t, name);
-                        if (symbol) {
-                            symbols.push(symbol);
-                        }
-                    });
-                    return symbols;
-                }
+                const symbols: Symbol[] = [];
+                const name = symbol.name;
+                forEach(getSymbolLinks(symbol).containingType.types, t => {
+                    const symbol = getPropertyOfType(t, name);
+                    if (symbol) {
+                        symbols.push(symbol);
+                    }
+                });
+                return symbols;
             }
             else if (symbol.flags & SymbolFlags.Transient) {
+                if ((symbol as SymbolLinks).leftSpread) {
+                    const links = symbol as SymbolLinks;
+                    return [links.leftSpread, links.rightSpread];
+                }
                 let target: Symbol;
                 let next = symbol;
                 while (next = getSymbolLinks(next).target) {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index dcff28d6a4887..61bbff691bc05 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2590,7 +2590,6 @@ namespace ts {
         /* @internal */ isReferenced?: boolean; // True if the symbol is referenced elsewhere
         /* @internal */ isReplaceableByMethod?: boolean; // Can this Javascript class property be replaced by a method symbol?
         /* @internal */ isAssigned?: boolean;   // True if the symbol is a parameter with assignments
-        /* @internal */ syntheticKind?: SyntheticSymbolKind; // Synthetic symbols are either spread or union/intersection
     }
 
     /* @internal */
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index b668fe6eb1582..53a4ad33f3400 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -4311,6 +4311,7 @@ namespace ts {
 namespace ts {
     export function getDefaultLibFileName(options: CompilerOptions): string {
         switch (options.target) {
+            case ScriptTarget.ESNext:
             case ScriptTarget.ES2017:
                 return "lib.es2017.d.ts";
             case ScriptTarget.ES2016:

From bd5ce284c9c2d8b29d131100615db437dde5ae28 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 7 Nov 2016 13:35:36 -0800
Subject: [PATCH 191/224] Set spread type symbols in checkObjectLiteral

Instead of getSpreadType.

Also clean up special-case handling inside getSpreadType to be more
readable.
---
 src/compiler/checker.ts                       | 19 ++++++++++---------
 .../baselines/reference/objectSpread.symbols  |  1 +
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 73e4e273d66b0..263ee47a6b702 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5881,7 +5881,7 @@ namespace ts {
          * this function should be called in a left folding style, with left = previous result of getSpreadType
          * and right = the new element to be spread.
          */
-        function getSpreadType(left: Type, right: Type, symbol: Symbol): ResolvedType | IntrinsicType {
+        function getSpreadType(left: Type, right: Type, isFromObjectLiteral: boolean): ResolvedType | IntrinsicType {
             Debug.assert(!!(left.flags & (TypeFlags.Object | TypeFlags.Any)) && !!(right.flags & (TypeFlags.Object | TypeFlags.Any)), "Only object types may be spread.");
             if (left.flags & TypeFlags.Any || right.flags & TypeFlags.Any) {
                 return anyType;
@@ -5900,14 +5900,14 @@ namespace ts {
                 numberIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.Number), getIndexInfoOfType(right, IndexKind.Number));
             }
 
-            const isFromSpread = right.symbol !== symbol;
             for (const rightProp of getPropertiesOfType(right)) {
+                // we approximate own properties as non-methods plus methods that are inside the object literal
+                const isOwnProperty = !(rightProp.flags & SymbolFlags.Method) || isFromObjectLiteral;
+                const isSetterWithoutGetter = rightProp.flags & SymbolFlags.SetAccessor && !(rightProp.flags & SymbolFlags.GetAccessor);
                 if (getDeclarationModifierFlagsFromSymbol(rightProp) & (ModifierFlags.Private | ModifierFlags.Protected)) {
                     skippedPrivateMembers[rightProp.name] = true;
                 }
-                else if (!(rightProp.flags & SymbolFlags.Method && isFromSpread) &&
-                         !(rightProp.flags & SymbolFlags.SetAccessor && !(rightProp.flags & SymbolFlags.GetAccessor))) {
-                    // skip methods from spreads and accessors with setters but no getters
+                else if (isOwnProperty && !isSetterWithoutGetter) {
                     members[rightProp.name] = rightProp;
                 }
             }
@@ -5937,7 +5937,7 @@ namespace ts {
                     members[leftProp.name] = leftProp;
                 }
             }
-            return createAnonymousType(symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
+            return createAnonymousType(undefined, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
         }
 
         function createLiteralType(flags: TypeFlags, text: string) {
@@ -10947,7 +10947,7 @@ namespace ts {
                 }
                 else if (memberDecl.kind === SyntaxKind.SpreadAssignment) {
                     if (propertiesArray.length > 0) {
-                        spread = getSpreadType(spread, createObjectLiteralType(), node.symbol);
+                        spread = getSpreadType(spread, createObjectLiteralType(), /*isFromObjectLiteral*/ true);
                         propertiesArray = [];
                         propertiesTable = createMap<Symbol>();
                         hasComputedStringProperty = false;
@@ -10959,7 +10959,7 @@ namespace ts {
                         error(memberDecl, Diagnostics.Spread_types_may_only_be_created_from_object_types);
                         return unknownType;
                     }
-                    spread = getSpreadType(spread, type, node.symbol);
+                    spread = getSpreadType(spread, type, /*isFromObjectLiteral*/ false);
                     continue;
                 }
                 else {
@@ -11003,9 +11003,10 @@ namespace ts {
 
             if (spread !== emptyObjectType) {
                 if (propertiesArray.length > 0) {
-                    spread = getSpreadType(spread, createObjectLiteralType(), node.symbol);
+                    spread = getSpreadType(spread, createObjectLiteralType(), /*isFromObjectLiteral*/ true);
                 }
                 spread.flags |= propagatedFlags;
+                spread.symbol = node.symbol;
                 return spread;
             }
 
diff --git a/tests/baselines/reference/objectSpread.symbols b/tests/baselines/reference/objectSpread.symbols
index 4b0a62a5a24ec..9946b313f52f3 100644
--- a/tests/baselines/reference/objectSpread.symbols
+++ b/tests/baselines/reference/objectSpread.symbols
@@ -182,6 +182,7 @@ let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } }
 >p : Symbol(p, Decl(objectSpread.ts, 49, 12))
 >plus : Symbol(plus, Decl(objectSpread.ts, 49, 23))
 >plus : Symbol(plus, Decl(objectSpread.ts, 49, 48))
+>this : Symbol(__object, Decl(objectSpread.ts, 41, 15))
 
 cplus.plus();
 >cplus.plus : Symbol(plus, Decl(objectSpread.ts, 49, 23))

From 4ffdea838a65cf948f4ace6e659fc7936c7ea9a7 Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Mon, 7 Nov 2016 13:36:08 -0800
Subject: [PATCH 192/224] Ports #12051 and #12032 into master (#12090)

* use local registry to check if typings package exist (#12014)

use local registry to check if typings package exist

* enable sending telemetry events to tsserver client (#12035)

enable sending telemetry events
---
 Jakefile.js                                   |   2 +
 .../unittests/tsserverProjectSystem.ts        |  33 +--
 src/harness/unittests/typingsInstaller.ts     | 263 ++++++++++--------
 src/server/editorServices.ts                  |   4 +-
 src/server/protocol.ts                        |  26 ++
 src/server/server.ts                          |  77 +++--
 src/server/session.ts                         |   6 +-
 src/server/shared.ts                          |  24 ++
 src/server/tsconfig.json                      |   1 +
 src/server/tsconfig.library.json              |   1 +
 src/server/types.d.ts                         |  24 +-
 .../typingsInstaller/nodeTypingsInstaller.ts  | 139 +++++----
 src/server/typingsInstaller/tsconfig.json     |   1 +
 .../typingsInstaller/typingsInstaller.ts      | 131 ++++-----
 src/server/utilities.ts                       |   2 +
 15 files changed, 412 insertions(+), 322 deletions(-)
 create mode 100644 src/server/shared.ts

diff --git a/Jakefile.js b/Jakefile.js
index 8ce70eb353f9e..fc2b6359355c5 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -171,6 +171,7 @@ var servicesSources = [
 
 var serverCoreSources = [
     "types.d.ts",
+    "shared.ts",
     "utilities.ts",
     "scriptVersionCache.ts",
     "typingsCache.ts",
@@ -193,6 +194,7 @@ var cancellationTokenSources = [
 
 var typingsInstallerSources = [
     "../types.d.ts",
+    "../shared.ts",
     "typingsInstaller.ts",
     "nodeTypingsInstaller.ts"
 ].map(function (f) {
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index 15cfa3f8c8e7c..ee6139b1215c6 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -18,7 +18,6 @@ namespace ts.projectSystem {
     };
 
     export interface PostExecAction {
-        readonly requestKind: TI.RequestKind;
         readonly success: boolean;
         readonly callback: TI.RequestCompletedAction;
     }
@@ -47,9 +46,14 @@ namespace ts.projectSystem {
 
     export class TestTypingsInstaller extends TI.TypingsInstaller implements server.ITypingsInstaller {
         protected projectService: server.ProjectService;
-        constructor(readonly globalTypingsCacheLocation: string, throttleLimit: number, readonly installTypingHost: server.ServerHost, log?: TI.Log) {
-            super(globalTypingsCacheLocation, safeList.path, throttleLimit, log);
-            this.init();
+        constructor(
+            readonly globalTypingsCacheLocation: string,
+            throttleLimit: number,
+            installTypingHost: server.ServerHost,
+            readonly typesRegistry = createMap<void>(),
+            telemetryEnabled?: boolean,
+            log?: TI.Log) {
+            super(installTypingHost, globalTypingsCacheLocation, safeList.path, throttleLimit, telemetryEnabled, log);
         }
 
         safeFileList = safeList.path;
@@ -63,9 +67,8 @@ namespace ts.projectSystem {
             }
         }
 
-        checkPendingCommands(expected: TI.RequestKind[]) {
-            assert.equal(this.postExecActions.length, expected.length, `Expected ${expected.length} post install actions`);
-            this.postExecActions.forEach((act, i) => assert.equal(act.requestKind, expected[i], "Unexpected post install action"));
+        checkPendingCommands(expectedCount: number) {
+            assert.equal(this.postExecActions.length, expectedCount, `Expected ${expectedCount} post install actions`);
         }
 
         onProjectClosed() {
@@ -79,15 +82,8 @@ namespace ts.projectSystem {
             return this.installTypingHost;
         }
 
-        executeRequest(requestKind: TI.RequestKind, _requestId: number, _args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
-            switch (requestKind) {
-                case TI.NpmViewRequest:
-                case TI.NpmInstallRequest:
-                    break;
-                default:
-                    assert.isTrue(false, `request ${requestKind} is not supported`);
-            }
-            this.addPostExecAction(requestKind, "success", cb);
+        installWorker(_requestId: number, _args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
+            this.addPostExecAction("success", cb);
         }
 
         sendResponse(response: server.SetTypings | server.InvalidateCachedTypings) {
@@ -99,12 +95,11 @@ namespace ts.projectSystem {
             this.install(request);
         }
 
-        addPostExecAction(requestKind: TI.RequestKind, stdout: string | string[], cb: TI.RequestCompletedAction) {
+        addPostExecAction(stdout: string | string[], cb: TI.RequestCompletedAction) {
             const out = typeof stdout === "string" ? stdout : createNpmPackageJsonString(stdout);
             const action: PostExecAction = {
                 success: !!out,
-                callback: cb,
-                requestKind
+                callback: cb
             };
             this.postExecActions.push(action);
         }
diff --git a/src/harness/unittests/typingsInstaller.ts b/src/harness/unittests/typingsInstaller.ts
index 356992d57176e..2dda506ad58f8 100644
--- a/src/harness/unittests/typingsInstaller.ts
+++ b/src/harness/unittests/typingsInstaller.ts
@@ -8,44 +8,44 @@ namespace ts.projectSystem {
     interface InstallerParams {
         globalTypingsCacheLocation?: string;
         throttleLimit?: number;
+        typesRegistry?: Map<void>;
+    }
+
+    function createTypesRegistry(...list: string[]): Map<void> {
+        const map = createMap<void>();
+        for (const l of list) {
+            map[l] = undefined;
+        }
+        return map;
     }
 
     class Installer extends TestTypingsInstaller {
-        constructor(host: server.ServerHost, p?: InstallerParams, log?: TI.Log) {
+        constructor(host: server.ServerHost, p?: InstallerParams, telemetryEnabled?: boolean, log?: TI.Log) {
             super(
                 (p && p.globalTypingsCacheLocation) || "/a/data",
                 (p && p.throttleLimit) || 5,
                 host,
+                (p && p.typesRegistry),
+                telemetryEnabled,
                 log);
         }
 
-        installAll(expectedView: typeof TI.NpmViewRequest[], expectedInstall: typeof TI.NpmInstallRequest[]) {
-            this.checkPendingCommands(expectedView);
-            this.executePendingCommands();
-            this.checkPendingCommands(expectedInstall);
+        installAll(expectedCount: number) {
+            this.checkPendingCommands(expectedCount);
             this.executePendingCommands();
         }
     }
 
-    describe("typingsInstaller", () => {
-        function executeCommand(self: Installer, host: TestServerHost, installedTypings: string[], typingFiles: FileOrFolder[], requestKind: TI.RequestKind, cb: TI.RequestCompletedAction): void {
-            switch (requestKind) {
-                case TI.NpmInstallRequest:
-                    self.addPostExecAction(requestKind, installedTypings, success => {
-                        for (const file of typingFiles) {
-                            host.createFileOrFolder(file, /*createParentDirectory*/ true);
-                        }
-                        cb(success);
-                    });
-                    break;
-                case TI.NpmViewRequest:
-                    self.addPostExecAction(requestKind, installedTypings, cb);
-                    break;
-                default:
-                    assert.isTrue(false, `unexpected request kind ${requestKind}`);
-                    break;
+    function executeCommand(self: Installer, host: TestServerHost, installedTypings: string[], typingFiles: FileOrFolder[], cb: TI.RequestCompletedAction): void {
+        self.addPostExecAction(installedTypings, success => {
+            for (const file of typingFiles) {
+                host.createFileOrFolder(file, /*createParentDirectory*/ true);
             }
-        }
+            cb(success);
+        });
+    }
+
+    describe("typingsInstaller", () => {
         it("configured projects (typings installed) 1", () => {
             const file1 = {
                 path: "/a/b/app.js",
@@ -79,12 +79,12 @@ namespace ts.projectSystem {
             const host = createServerHost([file1, tsconfig, packageJson]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host);
+                    super(host, { typesRegistry: createTypesRegistry("jquery") });
                 }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
                     const installedTypings = ["@types/jquery"];
                     const typingFiles = [jquery];
-                    executeCommand(this, host, installedTypings, typingFiles, requestKind, cb);
+                    executeCommand(this, host, installedTypings, typingFiles, cb);
                 }
             })();
 
@@ -95,7 +95,7 @@ namespace ts.projectSystem {
             const p = projectService.configuredProjects[0];
             checkProjectActualFiles(p, [file1.path]);
 
-            installer.installAll([TI.NpmViewRequest], [TI.NpmInstallRequest]);
+            installer.installAll(/*expectedCount*/ 1);
 
             checkNumberOfProjects(projectService, { configuredProjects: 1 });
             checkProjectActualFiles(p, [file1.path, jquery.path]);
@@ -123,12 +123,12 @@ namespace ts.projectSystem {
             const host = createServerHost([file1, packageJson]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host);
+                    super(host, { typesRegistry: createTypesRegistry("jquery") });
                 }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
                     const installedTypings = ["@types/jquery"];
                     const typingFiles = [jquery];
-                    executeCommand(this, host, installedTypings, typingFiles, requestKind, cb);
+                    executeCommand(this, host, installedTypings, typingFiles, cb);
                 }
             })();
 
@@ -139,7 +139,7 @@ namespace ts.projectSystem {
             const p = projectService.inferredProjects[0];
             checkProjectActualFiles(p, [file1.path]);
 
-            installer.installAll([TI.NpmViewRequest], [TI.NpmInstallRequest]);
+            installer.installAll(/*expectedCount*/ 1);
 
             checkNumberOfProjects(projectService, { inferredProjects: 1 });
             checkProjectActualFiles(p, [file1.path, jquery.path]);
@@ -167,7 +167,7 @@ namespace ts.projectSystem {
                 options: {},
                 rootFiles: [toExternalFile(file1.path)]
             });
-            installer.checkPendingCommands([]);
+            installer.checkPendingCommands(/*expectedCount*/ 0);
             // by default auto discovery will kick in if project contain only .js/.d.ts files
             // in this case project contain only ts files - no auto discovery
             projectService.checkNumberOfProjects({ externalProjects: 1 });
@@ -181,7 +181,7 @@ namespace ts.projectSystem {
             const host = createServerHost([file1]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host);
+                    super(host, { typesRegistry: createTypesRegistry("jquery") });
                 }
                 enqueueInstallTypingsRequest() {
                     assert(false, "auto discovery should not be enabled");
@@ -196,7 +196,7 @@ namespace ts.projectSystem {
                 rootFiles: [toExternalFile(file1.path)],
                 typingOptions: { include: ["jquery"] }
             });
-            installer.checkPendingCommands([]);
+            installer.checkPendingCommands(/*expectedCount*/ 0);
             // by default auto discovery will kick in if project contain only .js/.d.ts files
             // in this case project contain only ts files - no auto discovery even if typing options is set
             projectService.checkNumberOfProjects({ externalProjects: 1 });
@@ -215,16 +215,16 @@ namespace ts.projectSystem {
             let enqueueIsCalled = false;
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host);
+                    super(host, { typesRegistry: createTypesRegistry("jquery") });
                 }
                 enqueueInstallTypingsRequest(project: server.Project, typingOptions: TypingOptions, unresolvedImports: server.SortedReadonlyArray<string>) {
                     enqueueIsCalled = true;
                     super.enqueueInstallTypingsRequest(project, typingOptions, unresolvedImports);
                 }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, _args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
-                    const installedTypings = ["@types/jquery"];
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
+                    const installedTypings = ["@types/node"];
                     const typingFiles = [jquery];
-                    executeCommand(this, host, installedTypings, typingFiles, requestKind, cb);
+                    executeCommand(this, host, installedTypings, typingFiles, cb);
                 }
             })();
 
@@ -234,11 +234,11 @@ namespace ts.projectSystem {
                 projectFileName,
                 options: {},
                 rootFiles: [toExternalFile(file1.path)],
-                typingOptions: { enableAutoDiscovery: true, include: ["node"] }
+                typingOptions: { enableAutoDiscovery: true, include: ["jquery"] }
             });
 
             assert.isTrue(enqueueIsCalled, "expected enqueueIsCalled to be true");
-            installer.installAll([TI.NpmViewRequest], [TI.NpmInstallRequest]);
+            installer.installAll(/*expectedCount*/ 1);
 
             // autoDiscovery is set in typing options - use it even if project contains only .ts files
             projectService.checkNumberOfProjects({ externalProjects: 1 });
@@ -273,12 +273,12 @@ namespace ts.projectSystem {
             const host = createServerHost([file1, file2, file3]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host);
+                    super(host, { typesRegistry: createTypesRegistry("lodash", "react") });
                 }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, _args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
                     const installedTypings = ["@types/lodash", "@types/react"];
                     const typingFiles = [lodash, react];
-                    executeCommand(this, host, installedTypings, typingFiles, requestKind, cb);
+                    executeCommand(this, host, installedTypings, typingFiles, cb);
                 }
             })();
 
@@ -295,7 +295,7 @@ namespace ts.projectSystem {
             projectService.checkNumberOfProjects({ externalProjects: 1 });
             checkProjectActualFiles(p, [file1.path, file2.path, file3.path]);
 
-            installer.installAll([TI.NpmViewRequest, TI.NpmViewRequest], [TI.NpmInstallRequest], );
+            installer.installAll(/*expectedCount*/ 1);
 
             checkNumberOfProjects(projectService, { externalProjects: 1 });
             checkProjectActualFiles(p, [file1.path, file2.path, file3.path, lodash.path, react.path]);
@@ -317,16 +317,16 @@ namespace ts.projectSystem {
             let enqueueIsCalled = false;
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host);
+                    super(host, { typesRegistry: createTypesRegistry("jquery") });
                 }
                 enqueueInstallTypingsRequest(project: server.Project, typingOptions: TypingOptions, unresolvedImports: server.SortedReadonlyArray<string>) {
                     enqueueIsCalled = true;
                     super.enqueueInstallTypingsRequest(project, typingOptions, unresolvedImports);
                 }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, _args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
                     const installedTypings: string[] = [];
                     const typingFiles: FileOrFolder[] = [];
-                    executeCommand(this, host, installedTypings, typingFiles, requestKind, cb);
+                    executeCommand(this, host, installedTypings, typingFiles, cb);
                 }
             })();
 
@@ -343,7 +343,7 @@ namespace ts.projectSystem {
             projectService.checkNumberOfProjects({ externalProjects: 1 });
             checkProjectActualFiles(p, [file1.path, file2.path]);
 
-            installer.checkPendingCommands([]);
+            installer.checkPendingCommands(/*expectedCount*/ 0);
 
             checkNumberOfProjects(projectService, { externalProjects: 1 });
             checkProjectActualFiles(p, [file1.path, file2.path]);
@@ -396,12 +396,12 @@ namespace ts.projectSystem {
             const host = createServerHost([file1, file2, file3, packageJson]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host);
+                    super(host, { typesRegistry: createTypesRegistry("jquery", "commander", "moment", "express") });
                 }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, _args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
                     const installedTypings = ["@types/commander", "@types/express", "@types/jquery", "@types/moment"];
                     const typingFiles = [commander, express, jquery, moment];
-                    executeCommand(this, host, installedTypings, typingFiles, requestKind, cb);
+                    executeCommand(this, host, installedTypings, typingFiles, cb);
                 }
             })();
 
@@ -418,10 +418,7 @@ namespace ts.projectSystem {
             projectService.checkNumberOfProjects({ externalProjects: 1 });
             checkProjectActualFiles(p, [file1.path, file2.path, file3.path]);
 
-            installer.installAll(
-                [TI.NpmViewRequest, TI.NpmViewRequest, TI.NpmViewRequest, TI.NpmViewRequest],
-                [TI.NpmInstallRequest]
-            );
+            installer.installAll(/*expectedCount*/ 1);
 
             checkNumberOfProjects(projectService, { externalProjects: 1 });
             checkProjectActualFiles(p, [file1.path, file2.path, file3.path, commander.path, express.path, jquery.path, moment.path]);
@@ -475,11 +472,11 @@ namespace ts.projectSystem {
             const host = createServerHost([lodashJs, commanderJs, file3, packageJson]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host, { throttleLimit: 3 });
+                    super(host, { throttleLimit: 3, typesRegistry: createTypesRegistry("commander", "express", "jquery", "moment", "lodash") });
                 }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, _args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
                     const installedTypings = ["@types/commander", "@types/express", "@types/jquery", "@types/moment", "@types/lodash"];
-                    executeCommand(this, host, installedTypings, typingFiles, requestKind, cb);
+                    executeCommand(this, host, installedTypings, typingFiles, cb);
                 }
             })();
 
@@ -495,18 +492,7 @@ namespace ts.projectSystem {
             const p = projectService.externalProjects[0];
             projectService.checkNumberOfProjects({ externalProjects: 1 });
             checkProjectActualFiles(p, [lodashJs.path, commanderJs.path, file3.path]);
-            // expected 3 view requests in the queue
-            installer.checkPendingCommands([TI.NpmViewRequest, TI.NpmViewRequest, TI.NpmViewRequest]);
-            assert.equal(installer.pendingRunRequests.length, 2, "expected 2 pending requests");
-
-            // push view requests
-            installer.executePendingCommands();
-            // expected 2 remaining view requests in the queue
-            installer.checkPendingCommands([TI.NpmViewRequest, TI.NpmViewRequest]);
-            // push view requests
-            installer.executePendingCommands();
-            // expected one install request
-            installer.checkPendingCommands([TI.NpmInstallRequest]);
+            installer.checkPendingCommands(/*expectedCount*/ 1);
             installer.executePendingCommands();
             // expected all typings file to exist
             for (const f of typingFiles) {
@@ -565,22 +551,17 @@ namespace ts.projectSystem {
             const host = createServerHost([lodashJs, commanderJs, file3]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host, { throttleLimit: 3 });
-                }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
-                    if (requestKind === TI.NpmInstallRequest) {
-                        let typingFiles: (FileOrFolder & { typings: string })[] = [];
-                        if (args.indexOf("@types/commander") >= 0) {
-                            typingFiles = [commander, jquery, lodash, cordova];
-                        }
-                        else {
-                            typingFiles = [grunt, gulp];
-                        }
-                        executeCommand(this, host, typingFiles.map(f => f.typings), typingFiles, requestKind, cb);
+                    super(host, { throttleLimit: 1, typesRegistry: createTypesRegistry("commander", "jquery", "lodash", "cordova", "gulp", "grunt") });
+                }
+                installWorker(_requestId: number, args: string[], _cwd: string, cb: TI.RequestCompletedAction): void {
+                    let typingFiles: (FileOrFolder & { typings: string })[] = [];
+                    if (args.indexOf("@types/commander") >= 0) {
+                        typingFiles = [commander, jquery, lodash, cordova];
                     }
                     else {
-                        executeCommand(this, host, [], [], requestKind, cb);
+                        typingFiles = [grunt, gulp];
                     }
+                    executeCommand(this, host, typingFiles.map(f => f.typings), typingFiles, cb);
                 }
             })();
 
@@ -594,8 +575,8 @@ namespace ts.projectSystem {
                 typingOptions: { include: ["jquery", "cordova"] }
             });
 
-            installer.checkPendingCommands([TI.NpmViewRequest, TI.NpmViewRequest, TI.NpmViewRequest]);
-            assert.equal(installer.pendingRunRequests.length, 1, "expect one throttled request");
+            installer.checkPendingCommands(/*expectedCount*/ 1);
+            assert.equal(installer.pendingRunRequests.length, 0, "expect no throttled requests");
 
             // Create project #2 with 2 typings
             const projectFileName2 = "/a/app/test2.csproj";
@@ -605,7 +586,7 @@ namespace ts.projectSystem {
                 rootFiles: [toExternalFile(file3.path)],
                 typingOptions: { include: ["grunt", "gulp"] }
             });
-            assert.equal(installer.pendingRunRequests.length, 3, "expect three throttled request");
+            assert.equal(installer.pendingRunRequests.length, 1, "expect one throttled request");
 
             const p1 = projectService.externalProjects[0];
             const p2 = projectService.externalProjects[1];
@@ -613,16 +594,12 @@ namespace ts.projectSystem {
             checkProjectActualFiles(p1, [lodashJs.path, commanderJs.path, file3.path]);
             checkProjectActualFiles(p2, [file3.path]);
 
-
             installer.executePendingCommands();
-            // expected one view request from the first project and two - from the second one
-            installer.checkPendingCommands([TI.NpmViewRequest, TI.NpmViewRequest, TI.NpmViewRequest]);
-            assert.equal(installer.pendingRunRequests.length, 0, "expected no throttled requests");
 
-            installer.executePendingCommands();
+            // expected one install request from the second project
+            installer.checkPendingCommands(/*expectedCount*/ 1);
+            assert.equal(installer.pendingRunRequests.length, 0, "expected no throttled requests");
 
-            // should be two install requests from both projects
-            installer.checkPendingCommands([TI.NpmInstallRequest, TI.NpmInstallRequest]);
             installer.executePendingCommands();
 
             checkProjectActualFiles(p1, [lodashJs.path, commanderJs.path, file3.path, commander.path, jquery.path, lodash.path, cordova.path]);
@@ -653,12 +630,12 @@ namespace ts.projectSystem {
             const host = createServerHost([app, jsconfig, jquery, jqueryPackage]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host, { globalTypingsCacheLocation: "/tmp" });
+                    super(host, { globalTypingsCacheLocation: "/tmp", typesRegistry: createTypesRegistry("jquery") });
                 }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
                     const installedTypings = ["@types/jquery"];
                     const typingFiles = [jqueryDTS];
-                    executeCommand(this, host, installedTypings, typingFiles, requestKind, cb);
+                    executeCommand(this, host, installedTypings, typingFiles, cb);
                 }
             })();
 
@@ -669,7 +646,7 @@ namespace ts.projectSystem {
             const p = projectService.configuredProjects[0];
             checkProjectActualFiles(p, [app.path]);
 
-            installer.installAll([TI.NpmViewRequest], [TI.NpmInstallRequest]);
+            installer.installAll(/*expectedCount*/ 1);
 
             checkNumberOfProjects(projectService, { configuredProjects: 1 });
             checkProjectActualFiles(p, [app.path, jqueryDTS.path]);
@@ -699,12 +676,12 @@ namespace ts.projectSystem {
             const host = createServerHost([app, jsconfig, bowerJson]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host, { globalTypingsCacheLocation: "/tmp" });
+                    super(host, { globalTypingsCacheLocation: "/tmp", typesRegistry: createTypesRegistry("jquery") });
                 }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
                     const installedTypings = ["@types/jquery"];
                     const typingFiles = [jqueryDTS];
-                    executeCommand(this, host, installedTypings, typingFiles, requestKind, cb);
+                    executeCommand(this, host, installedTypings, typingFiles, cb);
                 }
             })();
 
@@ -715,7 +692,7 @@ namespace ts.projectSystem {
             const p = projectService.configuredProjects[0];
             checkProjectActualFiles(p, [app.path]);
 
-            installer.installAll([TI.NpmViewRequest], [TI.NpmInstallRequest]);
+            installer.installAll(/*expectedCount*/ 1);
 
             checkNumberOfProjects(projectService, { configuredProjects: 1 });
             checkProjectActualFiles(p, [app.path, jqueryDTS.path]);
@@ -742,23 +719,23 @@ namespace ts.projectSystem {
             const host = createServerHost([f, brokenPackageJson]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host, { globalTypingsCacheLocation: cachePath });
+                    super(host, { globalTypingsCacheLocation: cachePath, typesRegistry: createTypesRegistry("commander") });
                 }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
                     const installedTypings = ["@types/commander"];
                     const typingFiles = [commander];
-                    executeCommand(this, host, installedTypings, typingFiles, requestKind, cb);
+                    executeCommand(this, host, installedTypings, typingFiles, cb);
                 }
             })();
             const service = createProjectService(host, { typingsInstaller: installer });
             service.openClientFile(f.path);
 
-            installer.checkPendingCommands([]);
+            installer.checkPendingCommands(/*expectedCount*/ 0);
 
             host.reloadFS([f, fixedPackageJson]);
             host.triggerFileWatcherCallback(fixedPackageJson.path, /*removed*/ false);
-            // expected one view and one install request
-            installer.installAll([TI.NpmViewRequest], [TI.NpmInstallRequest]);
+            // expected install request
+            installer.installAll(/*expectedCount*/ 1);
 
             service.checkNumberOfProjects({ inferredProjects: 1 });
             checkProjectActualFiles(service.inferredProjects[0], [f.path, commander.path]);
@@ -783,12 +760,12 @@ namespace ts.projectSystem {
             const host = createServerHost([file]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host, { globalTypingsCacheLocation: cachePath });
+                    super(host, { globalTypingsCacheLocation: cachePath, typesRegistry: createTypesRegistry("node", "commander") });
                 }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
                     const installedTypings = ["@types/node", "@types/commander"];
                     const typingFiles = [node, commander];
-                    executeCommand(this, host, installedTypings, typingFiles, requestKind, cb);
+                    executeCommand(this, host, installedTypings, typingFiles, cb);
                 }
             })();
             const service = createProjectService(host, { typingsInstaller: installer });
@@ -797,7 +774,7 @@ namespace ts.projectSystem {
             service.checkNumberOfProjects({ inferredProjects: 1 });
             checkProjectActualFiles(service.inferredProjects[0], [file.path]);
 
-            installer.installAll([TI.NpmViewRequest, TI.NpmViewRequest], [TI.NpmInstallRequest]);
+            installer.installAll(/*expectedCount*/1);
 
             assert.isTrue(host.fileExists(node.path), "typings for 'node' should be created");
             assert.isTrue(host.fileExists(commander.path), "typings for 'commander' should be created");
@@ -822,14 +799,10 @@ namespace ts.projectSystem {
             const host = createServerHost([f1]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host, { globalTypingsCacheLocation: "/tmp" });
+                    super(host, { globalTypingsCacheLocation: "/tmp", typesRegistry: createTypesRegistry("foo") });
                 }
-                executeRequest(requestKind: TI.RequestKind, _requestId: number, args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
-                    if (requestKind === TI.NpmViewRequest) {
-                        // args should have only non-scoped packages - scoped packages are not yet supported
-                        assert.deepEqual(args, ["foo"]);
-                    }
-                    executeCommand(this, host, ["foo"], [], requestKind, cb);
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
+                    executeCommand(this, host, ["foo"], [], cb);
                 }
             })();
             const projectService = createProjectService(host, { typingsInstaller: installer });
@@ -844,7 +817,7 @@ namespace ts.projectSystem {
                 ["foo", "foo", "foo", "@bar/router", "@bar/common", "@bar/common"]
             );
 
-            installer.installAll([TI.NpmViewRequest], [TI.NpmInstallRequest]);
+            installer.installAll(/*expectedCount*/ 1);
         });
 
         it("cached unresolved typings are not recomputed if program structure did not change", () => {
@@ -934,16 +907,16 @@ namespace ts.projectSystem {
             const host = createServerHost([f1, packageJson]);
             const installer = new (class extends Installer {
                 constructor() {
-                    super(host, { globalTypingsCacheLocation: "/tmp" }, { isEnabled: () => true, writeLine: msg => messages.push(msg) });
+                    super(host, { globalTypingsCacheLocation: "/tmp" }, /*telemetryEnabled*/ false, { isEnabled: () => true, writeLine: msg => messages.push(msg) });
                 }
-                executeRequest() {
+                installWorker(_requestId: number, _args: string[], _cwd: string, _cb: server.typingsInstaller.RequestCompletedAction) {
                     assert(false, "runCommand should not be invoked");
                 }
             })();
             const projectService = createProjectService(host, { typingsInstaller: installer });
             projectService.openClientFile(f1.path);
 
-            installer.checkPendingCommands([]);
+            installer.checkPendingCommands(/*expectedCount*/ 0);
             assert.isTrue(messages.indexOf("Package name '; say ‘Hello from TypeScript!’ #' contains non URI safe characters") > 0, "should find package with invalid name");
         });
     });
@@ -978,4 +951,50 @@ namespace ts.projectSystem {
             assert.deepEqual(result.newTypingNames, ["bar"]);
         });
     });
+
+    describe("telemetry events", () => {
+        it ("should be received", () => {
+            const f1 = {
+                path: "/a/app.js",
+                content: ""
+            };
+            const package = {
+                path: "/a/package.json",
+                content: JSON.stringify({ dependencies: { "commander": "1.0.0" } })
+            };
+            const cachePath = "/a/cache/";
+            const commander = {
+                path: cachePath + "node_modules/@types/commander/index.d.ts",
+                content: "export let x: number"
+            };
+            const host = createServerHost([f1, package]);
+            let seenTelemetryEvent = false;
+            const installer = new (class extends Installer {
+                constructor() {
+                    super(host, { globalTypingsCacheLocation: cachePath, typesRegistry: createTypesRegistry("commander") }, /*telemetryEnabled*/ true);
+                }
+                installWorker(_requestId: number, _args: string[], _cwd: string, cb: server.typingsInstaller.RequestCompletedAction) {
+                    const installedTypings = ["@types/commander"];
+                    const typingFiles = [commander];
+                    executeCommand(this, host, installedTypings, typingFiles, cb);
+                }
+                sendResponse(response: server.SetTypings | server.InvalidateCachedTypings | server.TypingsInstallEvent) {
+                    if (response.kind === server.EventInstall) {
+                        assert.deepEqual(response.packagesToInstall, ["@types/commander"]);
+                        seenTelemetryEvent = true;
+                        return;
+                    }
+                    super.sendResponse(response);
+                }
+            })();
+            const projectService = createProjectService(host, { typingsInstaller: installer });
+            projectService.openClientFile(f1.path);
+
+            installer.installAll(/*expectedCount*/ 1);
+
+            assert.isTrue(seenTelemetryEvent);
+            checkNumberOfProjects(projectService, { inferredProjects: 1 });
+            checkProjectActualFiles(projectService.inferredProjects[0], [f1.path, commander.path]);
+        });
+    });
 }
\ No newline at end of file
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index a02becd87c486..bf760106b7435 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -286,10 +286,10 @@ namespace ts.server {
                 return;
             }
             switch (response.kind) {
-                case "set":
+                case ActionSet:
                     this.typingsCache.updateTypingsForProject(response.projectName, response.compilerOptions, response.typingOptions, response.unresolvedImports, response.typings);
                     break;
-                case "invalidate":
+                case ActionInvalidate:
                     this.typingsCache.deleteTypingsForProject(response.projectName);
                     break;
             }
diff --git a/src/server/protocol.ts b/src/server/protocol.ts
index 7da95e49575f5..d13caf7f01b0c 100644
--- a/src/server/protocol.ts
+++ b/src/server/protocol.ts
@@ -2057,6 +2057,32 @@ namespace ts.server.protocol {
         childItems?: NavigationTree[];
     }
 
+    export type TelemetryEventName = "telemetry";
+
+    export interface TelemetryEvent extends Event {
+        event: TelemetryEventName;
+        body: TelemetryEventBody;
+    }
+
+    export interface TelemetryEventBody {
+        telemetryEventName: string;
+        payload: any;
+    }
+
+    export type TypingsInstalledTelemetryEventName = "typingsInstalled";
+
+    export interface TypingsInstalledTelemetryEventBody extends TelemetryEventBody {
+        telemetryEventName: TypingsInstalledTelemetryEventName;
+        payload: TypingsInstalledTelemetryEventPayload;
+    }
+
+    export interface TypingsInstalledTelemetryEventPayload {
+        /**
+         * Comma separated list of installed typing packages
+         */
+        installedPackages: string;
+    }
+
     export interface NavBarResponse extends Response {
         body?: NavigationBarItem[];
     }
diff --git a/src/server/server.ts b/src/server/server.ts
index 5057a13dbd1bc..3b33554aaba6f 100644
--- a/src/server/server.ts
+++ b/src/server/server.ts
@@ -1,4 +1,5 @@
 /// <reference types="node" />
+/// <reference path="shared.ts" />
 /// <reference path="session.ts" />
 // used in fs.writeSync
 /* tslint:disable:no-null-keyword */
@@ -196,8 +197,10 @@ namespace ts.server {
         private socket: NodeSocket;
         private projectService: ProjectService;
         private throttledOperations: ThrottledOperations;
+        private telemetrySender: EventSender;
 
         constructor(
+            private readonly telemetryEnabled: boolean,
             private readonly logger: server.Logger,
             host: ServerHost,
             eventPort: number,
@@ -226,15 +229,22 @@ namespace ts.server {
             this.socket.write(formatMessage({ seq, type: "event", event, body }, this.logger, Buffer.byteLength, this.newLine), "utf8");
         }
 
+        setTelemetrySender(telemetrySender: EventSender) {
+            this.telemetrySender = telemetrySender;
+        }
+
         attach(projectService: ProjectService) {
             this.projectService = projectService;
             if (this.logger.hasLevel(LogLevel.requestTime)) {
                 this.logger.info("Binding...");
             }
 
-            const args: string[] = ["--globalTypingsCacheLocation", this.globalTypingsCacheLocation];
+            const args: string[] = [Arguments.GlobalCacheLocation, this.globalTypingsCacheLocation];
+            if (this.telemetryEnabled) {
+                args.push(Arguments.EnableTelemetry);
+            }
             if (this.logger.loggingEnabled() && this.logger.getLogFileName()) {
-                args.push("--logFile", combinePaths(getDirectoryPath(normalizeSlashes(this.logger.getLogFileName())), `ti-${process.pid}.log`));
+                args.push(Arguments.LogFile, combinePaths(getDirectoryPath(normalizeSlashes(this.logger.getLogFileName())), `ti-${process.pid}.log`));
             }
             const execArgv: string[] = [];
             {
@@ -280,12 +290,25 @@ namespace ts.server {
             });
         }
 
-        private handleMessage(response: SetTypings | InvalidateCachedTypings) {
+        private handleMessage(response: SetTypings | InvalidateCachedTypings | TypingsInstallEvent) {
             if (this.logger.hasLevel(LogLevel.verbose)) {
                 this.logger.info(`Received response: ${JSON.stringify(response)}`);
             }
+            if (response.kind === EventInstall) {
+                if (this.telemetrySender) {
+                    const body: protocol.TypingsInstalledTelemetryEventBody = {
+                        telemetryEventName: "typingsInstalled",
+                        payload: {
+                            installedPackages: response.packagesToInstall.join(",")
+                        }
+                    };
+                    const eventName: protocol.TelemetryEventName = "telemetry";
+                    this.telemetrySender.event(body, eventName);
+                }
+                return;
+            }
             this.projectService.updateTypingsForProject(response);
-            if (response.kind == "set" && this.socket) {
+            if (response.kind == ActionSet && this.socket) {
                 this.sendEvent(0, "setTypings", response);
             }
         }
@@ -300,18 +323,25 @@ namespace ts.server {
             useSingleInferredProject: boolean,
             disableAutomaticTypingAcquisition: boolean,
             globalTypingsCacheLocation: string,
+            telemetryEnabled: boolean,
             logger: server.Logger) {
-            super(
-                host,
-                cancellationToken,
-                useSingleInferredProject,
-                disableAutomaticTypingAcquisition
-                    ? nullTypingsInstaller
-                    : new NodeTypingsInstaller(logger, host, installerEventPort, globalTypingsCacheLocation, host.newLine),
-                Buffer.byteLength,
-                process.hrtime,
-                logger,
-                canUseEvents);
+                const typingsInstaller = disableAutomaticTypingAcquisition
+                    ? undefined
+                    : new NodeTypingsInstaller(telemetryEnabled, logger, host, installerEventPort, globalTypingsCacheLocation, host.newLine);
+
+                super(
+                    host,
+                    cancellationToken,
+                    useSingleInferredProject,
+                    typingsInstaller || nullTypingsInstaller,
+                    Buffer.byteLength,
+                    process.hrtime,
+                    logger,
+                    canUseEvents);
+
+                if (telemetryEnabled && typingsInstaller) {
+                    typingsInstaller.setTelemetrySender(this);
+                }
         }
 
         exit() {
@@ -538,17 +568,17 @@ namespace ts.server {
 
     let eventPort: number;
     {
-        const index = sys.args.indexOf("--eventPort");
-        if (index >= 0 && index < sys.args.length - 1) {
-            const v = parseInt(sys.args[index + 1]);
-            if (!isNaN(v)) {
-                eventPort = v;
-            }
+        const str = findArgument("--eventPort");
+        const v = str && parseInt(str);
+        if (!isNaN(v)) {
+            eventPort = v;
         }
     }
 
-    const useSingleInferredProject = sys.args.indexOf("--useSingleInferredProject") >= 0;
-    const disableAutomaticTypingAcquisition = sys.args.indexOf("--disableAutomaticTypingAcquisition") >= 0;
+    const useSingleInferredProject = hasArgument("--useSingleInferredProject");
+    const disableAutomaticTypingAcquisition = hasArgument("--disableAutomaticTypingAcquisition");
+    const telemetryEnabled = hasArgument(Arguments.EnableTelemetry);
+
     const ioSession = new IOSession(
         sys,
         cancellationToken,
@@ -557,6 +587,7 @@ namespace ts.server {
         useSingleInferredProject,
         disableAutomaticTypingAcquisition,
         getGlobalTypingsCacheLocation(),
+        telemetryEnabled,
         logger);
     process.on("uncaughtException", function (err: Error) {
         ioSession.logError(err, "unknown");
diff --git a/src/server/session.ts b/src/server/session.ts
index 545701f1449fa..b250393b7ffdb 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -73,6 +73,10 @@ namespace ts.server {
         project: Project;
     }
 
+    export interface EventSender {
+        event(payload: any, eventName: string): void;
+    }
+
     function allEditsBeforePos(edits: ts.TextChange[], pos: number) {
         for (const edit of edits) {
             if (textSpanEnd(edit.span) >= pos) {
@@ -165,7 +169,7 @@ namespace ts.server {
         return `Content-Length: ${1 + len}\r\n\r\n${json}${newLine}`;
     }
 
-    export class Session {
+    export class Session implements EventSender {
         private readonly gcTimer: GcTimer;
         protected projectService: ProjectService;
         private errorTimer: any; /*NodeJS.Timer | number*/
diff --git a/src/server/shared.ts b/src/server/shared.ts
new file mode 100644
index 0000000000000..81a1f7fb55bc2
--- /dev/null
+++ b/src/server/shared.ts
@@ -0,0 +1,24 @@
+/// <reference path="types.d.ts" />
+
+namespace ts.server {
+    export const ActionSet: ActionSet = "action::set";
+    export const ActionInvalidate: ActionInvalidate = "action::invalidate";
+    export const EventInstall: EventInstall = "event::install";
+
+    export namespace Arguments {
+        export const GlobalCacheLocation = "--globalTypingsCacheLocation";
+        export const LogFile = "--logFile";
+        export const EnableTelemetry = "--enableTelemetry";
+    }
+
+    export function hasArgument(argumentName: string) {
+        return sys.args.indexOf(argumentName) >= 0;
+    }
+
+    export function findArgument(argumentName: string) {
+        const index = sys.args.indexOf(argumentName);
+        return index >= 0 && index < sys.args.length - 1
+            ? sys.args[index + 1]
+            : undefined;
+    }
+}
\ No newline at end of file
diff --git a/src/server/tsconfig.json b/src/server/tsconfig.json
index a99994d97c5f9..85c8867916421 100644
--- a/src/server/tsconfig.json
+++ b/src/server/tsconfig.json
@@ -18,6 +18,7 @@
     "files": [
         "../services/shims.ts",
         "../services/utilities.ts",
+        "shared.ts",
         "utilities.ts",
         "scriptVersionCache.ts",
         "scriptInfo.ts",
diff --git a/src/server/tsconfig.library.json b/src/server/tsconfig.library.json
index e269629b55898..5483cc8ec289a 100644
--- a/src/server/tsconfig.library.json
+++ b/src/server/tsconfig.library.json
@@ -15,6 +15,7 @@
     "files": [
         "../services/shims.ts",
         "../services/utilities.ts",
+        "shared.ts",
         "utilities.ts",
         "scriptVersionCache.ts",
         "scriptInfo.ts",
diff --git a/src/server/types.d.ts b/src/server/types.d.ts
index ec2befe8fa9b6..95f9519cc388c 100644
--- a/src/server/types.d.ts
+++ b/src/server/types.d.ts
@@ -41,23 +41,33 @@ declare namespace ts.server {
         readonly kind: "closeProject";
     }
 
-    export type SetRequest = "set";
-    export type InvalidateRequest = "invalidate";
+    export type ActionSet = "action::set";
+    export type ActionInvalidate = "action::invalidate";
+    export type EventInstall = "event::install";
+
     export interface TypingInstallerResponse {
+        readonly kind: ActionSet | ActionInvalidate | EventInstall;
+    }
+
+    export interface ProjectResponse extends TypingInstallerResponse {
         readonly projectName: string;
-        readonly kind: SetRequest | InvalidateRequest;
     }
 
-    export interface SetTypings extends TypingInstallerResponse {
+    export interface SetTypings extends ProjectResponse {
         readonly typingOptions: ts.TypingOptions;
         readonly compilerOptions: ts.CompilerOptions;
         readonly typings: string[];
         readonly unresolvedImports: SortedReadonlyArray<string>;
-        readonly kind: SetRequest;
+        readonly kind: ActionSet;
+    }
+
+    export interface InvalidateCachedTypings extends ProjectResponse {
+        readonly kind: ActionInvalidate;
     }
 
-    export interface InvalidateCachedTypings extends TypingInstallerResponse {
-        readonly kind: InvalidateRequest;
+    export interface TypingsInstallEvent extends TypingInstallerResponse {
+        readonly packagesToInstall: ReadonlyArray<string>;
+        readonly kind: EventInstall;
     }
 
     export interface InstallTypingHost extends JsTyping.TypingResolutionHost {
diff --git a/src/server/typingsInstaller/nodeTypingsInstaller.ts b/src/server/typingsInstaller/nodeTypingsInstaller.ts
index 8941926493051..7020b6aa4f80b 100644
--- a/src/server/typingsInstaller/nodeTypingsInstaller.ts
+++ b/src/server/typingsInstaller/nodeTypingsInstaller.ts
@@ -33,42 +33,81 @@ namespace ts.server.typingsInstaller {
         }
     }
 
-    type HttpGet = {
-        (url: string, callback: (response: HttpResponse) => void): NodeJS.EventEmitter;
-    };
+    interface TypesRegistryFile {
+        entries: MapLike<void>;
+    }
+
+    function loadTypesRegistryFile(typesRegistryFilePath: string, host: InstallTypingHost, log: Log): Map<void> {
+        if (!host.fileExists(typesRegistryFilePath)) {
+            if (log.isEnabled()) {
+                log.writeLine(`Types registry file '${typesRegistryFilePath}' does not exist`);
+            }
+            return createMap<void>();
+        }
+        try {
+            const content = <TypesRegistryFile>JSON.parse(host.readFile(typesRegistryFilePath));
+            return createMap<void>(content.entries);
+        }
+        catch (e) {
+            if (log.isEnabled()) {
+                log.writeLine(`Error when loading types registry file '${typesRegistryFilePath}': ${(<Error>e).message}, ${(<Error>e).stack}`);
+            }
+            return createMap<void>();
+        }
+    }
 
-    interface HttpResponse extends NodeJS.ReadableStream {
-        statusCode: number;
-        statusMessage: string;
-        destroy(): void;
+    const TypesRegistryPackageName = "types-registry";
+    function getTypesRegistryFileLocation(globalTypingsCacheLocation: string): string {
+        return combinePaths(normalizeSlashes(globalTypingsCacheLocation), `node_modules/${TypesRegistryPackageName}/index.json`);
     }
 
+
     type Exec = {
         (command: string, options: { cwd: string }, callback?: (error: Error, stdout: string, stderr: string) => void): any
     };
 
+    type ExecSync = {
+        (command: string, options: { cwd: string, stdio: "ignore" }): any
+    };
+
     export class NodeTypingsInstaller extends TypingsInstaller {
         private readonly exec: Exec;
-        private readonly httpGet: HttpGet;
         private readonly npmPath: string;
-        readonly installTypingHost: InstallTypingHost = sys;
+        readonly typesRegistry: Map<void>;
 
-        constructor(globalTypingsCacheLocation: string, throttleLimit: number, log: Log) {
+        constructor(globalTypingsCacheLocation: string, throttleLimit: number, telemetryEnabled: boolean, log: Log) {
             super(
+                sys,
                 globalTypingsCacheLocation,
                 toPath("typingSafeList.json", __dirname, createGetCanonicalFileName(sys.useCaseSensitiveFileNames)),
                 throttleLimit,
+                telemetryEnabled,
                 log);
             if (this.log.isEnabled()) {
                 this.log.writeLine(`Process id: ${process.pid}`);
             }
             this.npmPath = getNPMLocation(process.argv[0]);
-            this.exec = require("child_process").exec;
-            this.httpGet = require("http").get;
+            let execSync: ExecSync;
+            ({ exec: this.exec, execSync } = require("child_process"));
+
+            this.ensurePackageDirectoryExists(globalTypingsCacheLocation);
+
+            try {
+                if (this.log.isEnabled()) {
+                    this.log.writeLine(`Updating ${TypesRegistryPackageName} npm package...`);
+                }
+                execSync(`${this.npmPath} install ${TypesRegistryPackageName}`, { cwd: globalTypingsCacheLocation, stdio: "ignore" });
+            }
+            catch (e) {
+                if (this.log.isEnabled()) {
+                    this.log.writeLine(`Error updating ${TypesRegistryPackageName} package: ${(<Error>e).message}`);
+                }
+            }
+
+            this.typesRegistry = loadTypesRegistryFile(getTypesRegistryFileLocation(globalTypingsCacheLocation), this.installTypingHost, this.log);
         }
 
-        init() {
-            super.init();
+        listen() {
             process.on("message", (req: DiscoverTypings | CloseProject) => {
                 switch (req.kind) {
                     case "discover":
@@ -90,66 +129,26 @@ namespace ts.server.typingsInstaller {
             }
         }
 
-        protected executeRequest(requestKind: RequestKind, requestId: number, args: string[], cwd: string, onRequestCompleted: RequestCompletedAction): void {
+        protected installWorker(requestId: number, args: string[], cwd: string, onRequestCompleted: RequestCompletedAction): void {
             if (this.log.isEnabled()) {
-                this.log.writeLine(`#${requestId} executing ${requestKind}, arguments'${JSON.stringify(args)}'.`);
-            }
-            switch (requestKind) {
-                case NpmViewRequest: {
-                        // const command = `${self.npmPath} view @types/${typing} --silent name`;
-                        // use http request to global npm registry instead of running npm view
-                        Debug.assert(args.length === 1);
-                        const url = `http://registry.npmjs.org/@types%2f${args[0]}`;
-                        const start = Date.now();
-                        this.httpGet(url, response => {
-                            let ok = false;
-                            if (this.log.isEnabled()) {
-                                this.log.writeLine(`${requestKind} #${requestId} request to ${url}:: status code ${response.statusCode}, status message '${response.statusMessage}', took ${Date.now() - start} ms`);
-                            }
-                            switch (response.statusCode) {
-                                case 200: // OK
-                                case 301: // redirect - Moved - treat package as present
-                                case 302: // redirect - Found - treat package as present
-                                    ok = true;
-                                    break;
-                            }
-                            response.destroy();
-                            onRequestCompleted(ok);
-                        }).on("error", (err: Error) => {
-                            if (this.log.isEnabled()) {
-                                this.log.writeLine(`${requestKind} #${requestId} query to npm registry failed with error ${err.message}, stack ${err.stack}`);
-                            }
-                            onRequestCompleted(/*success*/ false);
-                        });
-                    }
-                    break;
-                case NpmInstallRequest: {
-                        const command = `${this.npmPath} install ${args.join(" ")} --save-dev`;
-                        const start = Date.now();
-                        this.exec(command, { cwd }, (_err, stdout, stderr) => {
-                            if (this.log.isEnabled()) {
-                                this.log.writeLine(`${requestKind} #${requestId} took: ${Date.now() - start} ms${sys.newLine}stdout: ${stdout}${sys.newLine}stderr: ${stderr}`);
-                            }
-                            // treat any output on stdout as success
-                            onRequestCompleted(!!stdout);
-                        });
-                    }
-                    break;
-                default:
-                    Debug.assert(false, `Unknown request kind ${requestKind}`);
+                this.log.writeLine(`#${requestId} with arguments'${JSON.stringify(args)}'.`);
             }
+            const command = `${this.npmPath} install ${args.join(" ")} --save-dev`;
+            const start = Date.now();
+            this.exec(command, { cwd }, (_err, stdout, stderr) => {
+                if (this.log.isEnabled()) {
+                    this.log.writeLine(`npm install #${requestId} took: ${Date.now() - start} ms${sys.newLine}stdout: ${stdout}${sys.newLine}stderr: ${stderr}`);
+                }
+                // treat any output on stdout as success
+                onRequestCompleted(!!stdout);
+            });
         }
     }
 
-    function findArgument(argumentName: string) {
-        const index = sys.args.indexOf(argumentName);
-        return index >= 0 && index < sys.args.length - 1
-            ? sys.args[index + 1]
-            : undefined;
-    }
+    const logFilePath = findArgument(server.Arguments.LogFile);
+    const globalTypingsCacheLocation = findArgument(server.Arguments.GlobalCacheLocation);
+    const telemetryEnabled = hasArgument(server.Arguments.EnableTelemetry);
 
-    const logFilePath = findArgument("--logFile");
-    const globalTypingsCacheLocation = findArgument("--globalTypingsCacheLocation");
     const log = new FileLog(logFilePath);
     if (log.isEnabled()) {
         process.on("uncaughtException", (e: Error) => {
@@ -162,6 +161,6 @@ namespace ts.server.typingsInstaller {
         }
         process.exit(0);
     });
-    const installer = new NodeTypingsInstaller(globalTypingsCacheLocation, /*throttleLimit*/5, log);
-    installer.init();
+    const installer = new NodeTypingsInstaller(globalTypingsCacheLocation, /*throttleLimit*/5, telemetryEnabled, log);
+    installer.listen();
 }
\ No newline at end of file
diff --git a/src/server/typingsInstaller/tsconfig.json b/src/server/typingsInstaller/tsconfig.json
index c9b4d8f0ad14a..c6031b19aae48 100644
--- a/src/server/typingsInstaller/tsconfig.json
+++ b/src/server/typingsInstaller/tsconfig.json
@@ -17,6 +17,7 @@
     },
     "files": [
         "../types.d.ts",
+        "../shared.ts",
         "typingsInstaller.ts",
         "nodeTypingsInstaller.ts"
     ]
diff --git a/src/server/typingsInstaller/typingsInstaller.ts b/src/server/typingsInstaller/typingsInstaller.ts
index df043fc26ae06..a602a9f1a26c8 100644
--- a/src/server/typingsInstaller/typingsInstaller.ts
+++ b/src/server/typingsInstaller/typingsInstaller.ts
@@ -2,6 +2,7 @@
 /// <reference path="../../compiler/moduleNameResolver.ts" />
 /// <reference path="../../services/jsTyping.ts"/>
 /// <reference path="../types.d.ts"/>
+/// <reference path="../shared.ts"/>
 
 namespace ts.server.typingsInstaller {
     interface NpmConfig {
@@ -63,14 +64,8 @@ namespace ts.server.typingsInstaller {
         return PackageNameValidationResult.Ok;
     }
 
-    export const NpmViewRequest: "npm view" = "npm view";
-    export const NpmInstallRequest: "npm install" = "npm install";
-
-    export type RequestKind = typeof NpmViewRequest | typeof NpmInstallRequest;
-
     export type RequestCompletedAction = (success: boolean) => void;
     type PendingRequest = {
-        requestKind: RequestKind;
         requestId: number;
         args: string[];
         cwd: string;
@@ -87,19 +82,18 @@ namespace ts.server.typingsInstaller {
         private installRunCount = 1;
         private inFlightRequestCount = 0;
 
-        abstract readonly installTypingHost: InstallTypingHost;
+        abstract readonly typesRegistry: Map<void>;
 
         constructor(
+            readonly installTypingHost: InstallTypingHost,
             readonly globalCachePath: string,
             readonly safeListPath: Path,
             readonly throttleLimit: number,
+            readonly telemetryEnabled: boolean,
             protected readonly log = nullLog) {
             if (this.log.isEnabled()) {
                 this.log.writeLine(`Global cache location '${globalCachePath}', safe file path '${safeListPath}'`);
             }
-        }
-
-        init() {
             this.processCacheLocation(this.globalCachePath);
         }
 
@@ -224,7 +218,7 @@ namespace ts.server.typingsInstaller {
             this.knownCachesSet[cacheLocation] = true;
         }
 
-        private filterTypings(typingsToInstall: string[]) {
+        private filterAndMapToScopedName(typingsToInstall: string[]) {
             if (typingsToInstall.length === 0) {
                 return typingsToInstall;
             }
@@ -235,7 +229,14 @@ namespace ts.server.typingsInstaller {
                 }
                 const validationResult = validatePackageName(typing);
                 if (validationResult === PackageNameValidationResult.Ok) {
-                    result.push(typing);
+                    if (typing in this.typesRegistry) {
+                        result.push(`@types/${typing}`);
+                    }
+                    else {
+                        if (this.log.isEnabled()) {
+                            this.log.writeLine(`Entry for package '${typing}' does not exist in local types registry - skipping...`);
+                        }
+                    }
                 }
                 else {
                     // add typing name to missing set so we won't process it again
@@ -267,43 +268,59 @@ namespace ts.server.typingsInstaller {
             return result;
         }
 
-        private installTypings(req: DiscoverTypings, cachePath: string, currentlyCachedTypings: string[], typingsToInstall: string[]) {
+        protected ensurePackageDirectoryExists(directory: string) {
+            const npmConfigPath = combinePaths(directory, "package.json");
             if (this.log.isEnabled()) {
-                this.log.writeLine(`Installing typings ${JSON.stringify(typingsToInstall)}`);
+                this.log.writeLine(`Npm config file: ${npmConfigPath}`);
             }
-            typingsToInstall = this.filterTypings(typingsToInstall);
-            if (typingsToInstall.length === 0) {
+            if (!this.installTypingHost.fileExists(npmConfigPath)) {
                 if (this.log.isEnabled()) {
-                    this.log.writeLine(`All typings are known to be missing or invalid - no need to go any further`);
+                    this.log.writeLine(`Npm config file: '${npmConfigPath}' is missing, creating new one...`);
                 }
-                return;
+                this.ensureDirectoryExists(directory, this.installTypingHost);
+                this.installTypingHost.writeFile(npmConfigPath, "{}");
             }
+        }
 
-            const npmConfigPath = combinePaths(cachePath, "package.json");
+        private installTypings(req: DiscoverTypings, cachePath: string, currentlyCachedTypings: string[], typingsToInstall: string[]) {
             if (this.log.isEnabled()) {
-                this.log.writeLine(`Npm config file: ${npmConfigPath}`);
+                this.log.writeLine(`Installing typings ${JSON.stringify(typingsToInstall)}`);
             }
-            if (!this.installTypingHost.fileExists(npmConfigPath)) {
+            const scopedTypings = this.filterAndMapToScopedName(typingsToInstall);
+            if (scopedTypings.length === 0) {
                 if (this.log.isEnabled()) {
-                    this.log.writeLine(`Npm config file: '${npmConfigPath}' is missing, creating new one...`);
+                    this.log.writeLine(`All typings are known to be missing or invalid - no need to go any further`);
                 }
-                this.ensureDirectoryExists(cachePath, this.installTypingHost);
-                this.installTypingHost.writeFile(npmConfigPath, "{}");
+                return;
             }
 
-            this.runInstall(cachePath, typingsToInstall, installedTypings => {
+            this.ensurePackageDirectoryExists(cachePath);
+
+            const requestId = this.installRunCount;
+            this.installRunCount++;
+
+            this.installTypingsAsync(requestId, scopedTypings, cachePath, ok => {
+                if (this.telemetryEnabled) {
+                    this.sendResponse(<TypingsInstallEvent>{
+                        kind: EventInstall,
+                        packagesToInstall: scopedTypings
+                    });
+                }
+
+                if (!ok) {
+                    return;
+                }
+
                 // TODO: watch project directory
                 if (this.log.isEnabled()) {
-                    this.log.writeLine(`Requested to install typings ${JSON.stringify(typingsToInstall)}, installed typings ${JSON.stringify(installedTypings)}`);
+                    this.log.writeLine(`Requested to install typings ${JSON.stringify(scopedTypings)}, installed typings ${JSON.stringify(scopedTypings)}`);
                 }
-                const installedPackages: Map<true> = createMap<true>();
                 const installedTypingFiles: string[] = [];
-                for (const t of installedTypings) {
+                for (const t of scopedTypings) {
                     const packageName = getBaseFileName(t);
                     if (!packageName) {
                         continue;
                     }
-                    installedPackages[packageName] = true;
                     const typingFile = typingToFileName(cachePath, packageName, this.installTypingHost);
                     if (!typingFile) {
                         continue;
@@ -316,53 +333,11 @@ namespace ts.server.typingsInstaller {
                 if (this.log.isEnabled()) {
                     this.log.writeLine(`Installed typing files ${JSON.stringify(installedTypingFiles)}`);
                 }
-                for (const toInstall of typingsToInstall) {
-                    if (!installedPackages[toInstall]) {
-                        if (this.log.isEnabled()) {
-                            this.log.writeLine(`New missing typing package '${toInstall}'`);
-                        }
-                        this.missingTypingsSet[toInstall] = true;
-                    }
-                }
 
                 this.sendResponse(this.createSetTypings(req, currentlyCachedTypings.concat(installedTypingFiles)));
             });
         }
 
-        private runInstall(cachePath: string, typingsToInstall: string[], postInstallAction: (installedTypings: string[]) => void): void {
-            const requestId = this.installRunCount;
-
-            this.installRunCount++;
-            let execInstallCmdCount = 0;
-            const filteredTypings: string[] = [];
-            for (const typing of typingsToInstall) {
-                filterExistingTypings(this, typing);
-            }
-
-            function filterExistingTypings(self: TypingsInstaller, typing: string) {
-                self.execAsync(NpmViewRequest, requestId, [typing], cachePath, ok => {
-                    if (ok) {
-                        filteredTypings.push(typing);
-                    }
-                    execInstallCmdCount++;
-                    if (execInstallCmdCount === typingsToInstall.length) {
-                        installFilteredTypings(self, filteredTypings);
-                    }
-                });
-            }
-
-            function installFilteredTypings(self: TypingsInstaller, filteredTypings: string[]) {
-                if (filteredTypings.length === 0) {
-                    postInstallAction([]);
-                    return;
-                }
-                const scopedTypings = filteredTypings.map(t => "@types/" + t);
-                self.execAsync(NpmInstallRequest, requestId, scopedTypings, cachePath, ok => {
-                    postInstallAction(ok ? scopedTypings : []);
-                });
-            }
-        }
-
         private ensureDirectoryExists(directory: string, host: InstallTypingHost): void {
             const directoryName = getDirectoryPath(directory);
             if (!host.directoryExists(directoryName)) {
@@ -389,7 +364,7 @@ namespace ts.server.typingsInstaller {
                         this.log.writeLine(`Got FS notification for ${f}, handler is already invoked '${isInvoked}'`);
                     }
                     if (!isInvoked) {
-                        this.sendResponse({ projectName: projectName, kind: "invalidate" });
+                        this.sendResponse({ projectName: projectName, kind: server.ActionInvalidate });
                         isInvoked = true;
                     }
                 });
@@ -405,12 +380,12 @@ namespace ts.server.typingsInstaller {
                 compilerOptions: request.compilerOptions,
                 typings,
                 unresolvedImports: request.unresolvedImports,
-                kind: "set"
+                kind: server.ActionSet
             };
         }
 
-        private execAsync(requestKind: RequestKind, requestId: number, args: string[], cwd: string, onRequestCompleted: RequestCompletedAction): void {
-            this.pendingRunRequests.unshift({ requestKind, requestId, args, cwd, onRequestCompleted });
+        private installTypingsAsync(requestId: number, args: string[], cwd: string, onRequestCompleted: RequestCompletedAction): void {
+            this.pendingRunRequests.unshift({ requestId, args, cwd, onRequestCompleted });
             this.executeWithThrottling();
         }
 
@@ -418,7 +393,7 @@ namespace ts.server.typingsInstaller {
             while (this.inFlightRequestCount < this.throttleLimit && this.pendingRunRequests.length) {
                 this.inFlightRequestCount++;
                 const request = this.pendingRunRequests.pop();
-                this.executeRequest(request.requestKind, request.requestId, request.args, request.cwd, ok => {
+                this.installWorker(request.requestId, request.args, request.cwd, ok => {
                     this.inFlightRequestCount--;
                     request.onRequestCompleted(ok);
                     this.executeWithThrottling();
@@ -426,7 +401,7 @@ namespace ts.server.typingsInstaller {
             }
         }
 
-        protected abstract executeRequest(requestKind: RequestKind, requestId: number, args: string[], cwd: string, onRequestCompleted: RequestCompletedAction): void;
-        protected abstract sendResponse(response: SetTypings | InvalidateCachedTypings): void;
+        protected abstract installWorker(requestId: number, args: string[], cwd: string, onRequestCompleted: RequestCompletedAction): void;
+        protected abstract sendResponse(response: SetTypings | InvalidateCachedTypings | TypingsInstallEvent): void;
     }
 }
\ No newline at end of file
diff --git a/src/server/utilities.ts b/src/server/utilities.ts
index 8806b759e3f8d..9a832d22c8d5c 100644
--- a/src/server/utilities.ts
+++ b/src/server/utilities.ts
@@ -1,4 +1,5 @@
 /// <reference path="types.d.ts" />
+/// <reference path="shared.ts" />
 
 namespace ts.server {
     export enum LogLevel {
@@ -10,6 +11,7 @@ namespace ts.server {
 
     export const emptyArray: ReadonlyArray<any> = [];
 
+
     export interface Logger {
         close(): void;
         hasLevel(level: LogLevel): boolean;

From e1c50e1c406a27a505f4c8393a81f2b1232d51ae Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 7 Nov 2016 13:57:26 -0800
Subject: [PATCH 193/224] Address more PR comments

---
 src/compiler/checker.ts | 27 +++++++++------------------
 1 file changed, 9 insertions(+), 18 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 263ee47a6b702..8ac6b0f647190 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4488,10 +4488,9 @@ namespace ts {
 
         function getPropertiesOfType(type: Type): Symbol[] {
             type = getApparentType(type);
-            if (type.flags & TypeFlags.UnionOrIntersection) {
-                return getPropertiesOfUnionOrIntersectionType(<UnionType>type);
-            }
-            return getPropertiesOfObjectType(type);
+            return type.flags & TypeFlags.UnionOrIntersection ?
+                getPropertiesOfUnionOrIntersectionType(<UnionType>type) :
+                getPropertiesOfObjectType(type);
         }
 
         /**
@@ -4581,9 +4580,6 @@ namespace ts {
             result.hasNonUniformType = hasNonUniformType;
             result.isPartial = isPartial;
             result.declarations = declarations;
-            if (declarations.length) {
-                result.valueDeclaration = declarations[0];
-            }
             result.isReadonly = isReadonly;
             result.type = containingType.flags & TypeFlags.Union ? getUnionType(propTypes) : getIntersectionType(propTypes);
             return result;
@@ -5057,7 +5053,7 @@ namespace ts {
             const declaration = getIndexDeclarationOfSymbol(symbol, kind);
             if (declaration) {
                 return createIndexInfo(declaration.type ? getTypeFromTypeNode(declaration.type) : anyType,
-                                       (getModifierFlags(declaration) & ModifierFlags.Readonly) !== 0, declaration);
+                    (getModifierFlags(declaration) & ModifierFlags.Readonly) !== 0, declaration);
             }
             return undefined;
         }
@@ -5926,9 +5922,6 @@ namespace ts {
                         result.leftSpread = leftProp;
                         result.rightSpread = rightProp;
                         result.declarations = declarations;
-                        if (declarations.length) {
-                            result.valueDeclaration = declarations[0];
-                        }
                         result.isReadonly = isReadonlySymbol(leftProp) || isReadonlySymbol(rightProp);
                         members[leftProp.name] = result;
                     }
@@ -15196,11 +15189,9 @@ namespace ts {
             forEach(node.members, checkSourceElement);
             if (produceDiagnostics) {
                 const type = getTypeFromTypeLiteralOrFunctionOrConstructorTypeNode(node);
-                if (type.flags & TypeFlags.Object) {
-                    checkIndexConstraints(type);
-                    checkTypeForDuplicateIndexSignatures(node);
-                    checkObjectTypeForDuplicateDeclarations(node);
-                }
+                checkIndexConstraints(type);
+                checkTypeForDuplicateIndexSignatures(node);
+                checkObjectTypeForDuplicateDeclarations(node);
             }
         }
 
@@ -17259,7 +17250,7 @@ namespace ts {
                 // perform property check if property or indexer is declared in 'type'
                 // this allows to rule out cases when both property and indexer are inherited from the base class
                 let errorNode: Node;
-                    if (prop.valueDeclaration.name.kind === SyntaxKind.ComputedPropertyName || prop.parent === containingType.symbol) {
+                if (prop.valueDeclaration.name.kind === SyntaxKind.ComputedPropertyName || prop.parent === containingType.symbol) {
                     errorNode = prop.valueDeclaration;
                 }
                 else if (indexDeclaration) {
@@ -20538,7 +20529,7 @@ namespace ts {
                     continue;
                 }
                 const name = prop.name;
-                if (name && name.kind === SyntaxKind.ComputedPropertyName) {
+                if (name.kind === SyntaxKind.ComputedPropertyName) {
                     // If the name is not a ComputedPropertyName, the grammar checking will skip it
                     checkGrammarComputedPropertyName(<ComputedPropertyName>name);
                 }

From 0173a3fa790ca49b74d609c410c77d363e18229d Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Mon, 7 Nov 2016 15:48:46 -0800
Subject: [PATCH 194/224] return empty file watcher in case if target directory
 does not exist (#12091)

* return empty file watcher in case if target directory does not exist

* linter
---
 src/compiler/sys.ts                           |  3 ++-
 .../unittests/tsserverProjectSystem.ts        | 27 +++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index 13bbfc2ab153f..9cf95d6de9b92 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -439,6 +439,7 @@ namespace ts {
                 return filter<string>(_fs.readdirSync(path), dir => fileSystemEntryExists(combinePaths(path, dir), FileSystemEntryKind.Directory));
             }
 
+            const noOpFileWatcher: FileWatcher = { close: noop };
             const nodeSystem: System = {
                 args: process.argv.slice(2),
                 newLine: _os.EOL,
@@ -475,7 +476,7 @@ namespace ts {
                     // (ref: https://github.com/nodejs/node/pull/2649 and https://github.com/Microsoft/TypeScript/issues/4643)
                     let options: any;
                     if (!directoryExists(directoryName)) {
-                        return;
+                        return noOpFileWatcher;
                     }
 
                     if (isNode4OrLater() && (process.platform === "win32" || process.platform === "darwin")) {
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index ee6139b1215c6..c3974f037728e 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -1964,6 +1964,33 @@ namespace ts.projectSystem {
             projectService.checkNumberOfProjects({ configuredProjects: 1 });
             checkProjectActualFiles(projectService.configuredProjects[0], [libES5.path, libES2015Promise.path, app.path]);
         });
+
+        it("should handle non-existing directories in config file", () => {
+            const f = {
+                path: "/a/src/app.ts",
+                content: "let x = 1;"
+            };
+            const config = {
+                path: "/a/tsconfig.json",
+                content: JSON.stringify({
+                    compilerOptions: {},
+                    include: [
+                        "src/**/*",
+                        "notexistingfolder/*"
+                    ]
+                })
+            };
+            const host = createServerHost([f, config]);
+            const projectService = createProjectService(host);
+            projectService.openClientFile(f.path);
+            projectService.checkNumberOfProjects({ configuredProjects: 1 });
+
+            projectService.closeClientFile(f.path);
+            projectService.checkNumberOfProjects({ configuredProjects: 0 });
+
+            projectService.openClientFile(f.path);
+            projectService.checkNumberOfProjects({ configuredProjects: 1 });
+        });
     });
 
     describe("prefer typings to js", () => {

From be2e8e85d63f472a5a7762e1e56316026156317c Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Mon, 7 Nov 2016 15:49:19 -0800
Subject: [PATCH 195/224] property handle missing config files in external
 projects (#12094)

---
 .../unittests/tsserverProjectSystem.ts        | 21 +++++++++++++++++++
 src/server/editorServices.ts                  |  4 +++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index c3974f037728e..62c0957d6a37e 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -2249,6 +2249,27 @@ namespace ts.projectSystem {
             assert.equal(diags.length, 0);
         });
 
+        it("should property handle missing config files", () => {
+            const f1 = {
+                path: "/a/b/app.ts",
+                content: "let x = 1"
+            };
+            const config = {
+                path: "/a/b/tsconfig.json",
+                content: "{}"
+            };
+            const projectName = "project1";
+            const host = createServerHost([f1]);
+            const projectService = createProjectService(host);
+            projectService.openExternalProject({ rootFiles: toExternalFiles([f1.path, config.path]), options: {}, projectFileName: projectName });
+
+            // should have one external project since config file is missing
+            projectService.checkNumberOfProjects({ externalProjects: 1 });
+
+            host.reloadFS([f1, config]);
+            projectService.openExternalProject({ rootFiles: toExternalFiles([f1.path, config.path]), options: {}, projectFileName: projectName });
+            projectService.checkNumberOfProjects({ configuredProjects: 1 });
+        });
     });
 
     describe("add the missing module file for inferred project", () => {
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index bf760106b7435..269eea064647d 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -1288,7 +1288,9 @@ namespace ts.server {
             for (const file of proj.rootFiles) {
                 const normalized = toNormalizedPath(file.fileName);
                 if (getBaseFileName(normalized) === "tsconfig.json") {
-                    (tsConfigFiles || (tsConfigFiles = [])).push(normalized);
+                    if (this.host.fileExists(normalized)) {
+                        (tsConfigFiles || (tsConfigFiles = [])).push(normalized);
+                    }
                 }
                 else {
                     rootFiles.push(file);

From ddc4ae7eac9526b5dbd6624f89a2f0308b32b425 Mon Sep 17 00:00:00 2001
From: Ron Buckton <ron.buckton@microsoft.com>
Date: Mon, 7 Nov 2016 16:03:04 -0800
Subject: [PATCH 196/224] Reuse subtree transform flags for incrementally
 parsed nodes (#12088)

---
 src/compiler/binder.ts                     | 66 +++++++++++++++++++++-
 src/compiler/visitor.ts                    | 60 --------------------
 src/harness/unittests/incrementalParser.ts | 24 +++++---
 src/services/services.ts                   |  2 -
 4 files changed, 81 insertions(+), 71 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 1d721e2db90f7..112a53e88ece6 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -560,6 +560,7 @@ namespace ts {
                 skipTransformFlagAggregation = true;
                 bindChildrenWorker(node);
                 skipTransformFlagAggregation = false;
+                subtreeTransformFlags |= node.transformFlags & ~getTransformFlagsSubtreeExclusions(node.kind);
             }
             else {
                 const savedSubtreeTransformFlags = subtreeTransformFlags;
@@ -895,8 +896,8 @@ namespace ts {
             const enclosingLabeledStatement = node.parent.kind === SyntaxKind.LabeledStatement
                 ? lastOrUndefined(activeLabels)
                 : undefined;
-            // if do statement is wrapped in labeled statement then target labels for break/continue with or without 
-            // label should be the same 
+            // if do statement is wrapped in labeled statement then target labels for break/continue with or without
+            // label should be the same
             const preConditionLabel = enclosingLabeledStatement ? enclosingLabeledStatement.continueTarget : createBranchLabel();
             const postDoLabel = enclosingLabeledStatement ? enclosingLabeledStatement.breakTarget : createBranchLabel();
             addAntecedent(preDoLabel, currentFlow);
@@ -3206,4 +3207,65 @@ namespace ts {
         node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
         return transformFlags & ~excludeFlags;
     }
+
+    /**
+     * Gets the transform flags to exclude when unioning the transform flags of a subtree.
+     *
+     * NOTE: This needs to be kept up-to-date with the exclusions used in `computeTransformFlagsForNode`.
+     *       For performance reasons, `computeTransformFlagsForNode` uses local constant values rather
+     *       than calling this function.
+     */
+    /* @internal */
+    export function getTransformFlagsSubtreeExclusions(kind: SyntaxKind) {
+        if (kind >= SyntaxKind.FirstTypeNode && kind <= SyntaxKind.LastTypeNode) {
+            return TransformFlags.TypeExcludes;
+        }
+
+        switch (kind) {
+            case SyntaxKind.CallExpression:
+            case SyntaxKind.NewExpression:
+            case SyntaxKind.ArrayLiteralExpression:
+                return TransformFlags.ArrayLiteralOrCallOrNewExcludes;
+            case SyntaxKind.ModuleDeclaration:
+                return TransformFlags.ModuleExcludes;
+            case SyntaxKind.Parameter:
+                return TransformFlags.ParameterExcludes;
+            case SyntaxKind.ArrowFunction:
+                return TransformFlags.ArrowFunctionExcludes;
+            case SyntaxKind.FunctionExpression:
+            case SyntaxKind.FunctionDeclaration:
+                return TransformFlags.FunctionExcludes;
+            case SyntaxKind.VariableDeclarationList:
+                return TransformFlags.VariableDeclarationListExcludes;
+            case SyntaxKind.ClassDeclaration:
+            case SyntaxKind.ClassExpression:
+                return TransformFlags.ClassExcludes;
+            case SyntaxKind.Constructor:
+                return TransformFlags.ConstructorExcludes;
+            case SyntaxKind.MethodDeclaration:
+            case SyntaxKind.GetAccessor:
+            case SyntaxKind.SetAccessor:
+                return TransformFlags.MethodOrAccessorExcludes;
+            case SyntaxKind.AnyKeyword:
+            case SyntaxKind.NumberKeyword:
+            case SyntaxKind.NeverKeyword:
+            case SyntaxKind.StringKeyword:
+            case SyntaxKind.BooleanKeyword:
+            case SyntaxKind.SymbolKeyword:
+            case SyntaxKind.VoidKeyword:
+            case SyntaxKind.TypeParameter:
+            case SyntaxKind.PropertySignature:
+            case SyntaxKind.MethodSignature:
+            case SyntaxKind.CallSignature:
+            case SyntaxKind.ConstructSignature:
+            case SyntaxKind.IndexSignature:
+            case SyntaxKind.InterfaceDeclaration:
+            case SyntaxKind.TypeAliasDeclaration:
+                return TransformFlags.TypeExcludes;
+            case SyntaxKind.ObjectLiteralExpression:
+                return TransformFlags.ObjectLiteralExcludes;
+            default:
+                return TransformFlags.NodeExcludes;
+        }
+    }
 }
diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index 45b82a6a08a2e..34cc2e074367a 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -1270,66 +1270,6 @@ namespace ts {
         return transformFlags | aggregateTransformFlagsForNode(child);
     }
 
-    /**
-     * Gets the transform flags to exclude when unioning the transform flags of a subtree.
-     *
-     * NOTE: This needs to be kept up-to-date with the exclusions used in `computeTransformFlagsForNode`.
-     *       For performance reasons, `computeTransformFlagsForNode` uses local constant values rather
-     *       than calling this function.
-     */
-    function getTransformFlagsSubtreeExclusions(kind: SyntaxKind) {
-        if (kind >= SyntaxKind.FirstTypeNode && kind <= SyntaxKind.LastTypeNode) {
-            return TransformFlags.TypeExcludes;
-        }
-
-        switch (kind) {
-            case SyntaxKind.CallExpression:
-            case SyntaxKind.NewExpression:
-            case SyntaxKind.ArrayLiteralExpression:
-                return TransformFlags.ArrayLiteralOrCallOrNewExcludes;
-            case SyntaxKind.ModuleDeclaration:
-                return TransformFlags.ModuleExcludes;
-            case SyntaxKind.Parameter:
-                return TransformFlags.ParameterExcludes;
-            case SyntaxKind.ArrowFunction:
-                return TransformFlags.ArrowFunctionExcludes;
-            case SyntaxKind.FunctionExpression:
-            case SyntaxKind.FunctionDeclaration:
-                return TransformFlags.FunctionExcludes;
-            case SyntaxKind.VariableDeclarationList:
-                return TransformFlags.VariableDeclarationListExcludes;
-            case SyntaxKind.ClassDeclaration:
-            case SyntaxKind.ClassExpression:
-                return TransformFlags.ClassExcludes;
-            case SyntaxKind.Constructor:
-                return TransformFlags.ConstructorExcludes;
-            case SyntaxKind.MethodDeclaration:
-            case SyntaxKind.GetAccessor:
-            case SyntaxKind.SetAccessor:
-                return TransformFlags.MethodOrAccessorExcludes;
-            case SyntaxKind.AnyKeyword:
-            case SyntaxKind.NumberKeyword:
-            case SyntaxKind.NeverKeyword:
-            case SyntaxKind.StringKeyword:
-            case SyntaxKind.BooleanKeyword:
-            case SyntaxKind.SymbolKeyword:
-            case SyntaxKind.VoidKeyword:
-            case SyntaxKind.TypeParameter:
-            case SyntaxKind.PropertySignature:
-            case SyntaxKind.MethodSignature:
-            case SyntaxKind.CallSignature:
-            case SyntaxKind.ConstructSignature:
-            case SyntaxKind.IndexSignature:
-            case SyntaxKind.InterfaceDeclaration:
-            case SyntaxKind.TypeAliasDeclaration:
-                return TransformFlags.TypeExcludes;
-            case SyntaxKind.ObjectLiteralExpression:
-                return TransformFlags.ObjectLiteralExcludes;
-            default:
-                return TransformFlags.NodeExcludes;
-        }
-    }
-
     export namespace Debug {
         export const failNotOptional = shouldAssert(AssertionLevel.Normal)
             ? (message?: string) => assert(false, message || "Node not optional.")
diff --git a/src/harness/unittests/incrementalParser.ts b/src/harness/unittests/incrementalParser.ts
index 0082207e6994f..6088e5fe082b5 100644
--- a/src/harness/unittests/incrementalParser.ts
+++ b/src/harness/unittests/incrementalParser.ts
@@ -44,10 +44,10 @@ namespace ts {
 
     // NOTE: 'reusedElements' is the expected count of elements reused from the old tree to the new
     // tree.  It may change as we tweak the parser.  If the count increases then that should always
-    // be a good thing.  If it decreases, that's not great (less reusability), but that may be 
-    // unavoidable.  If it does decrease an investigation should be done to make sure that things 
+    // be a good thing.  If it decreases, that's not great (less reusability), but that may be
+    // unavoidable.  If it does decrease an investigation should be done to make sure that things
     // are still ok and we're still appropriately reusing most of the tree.
-    function compareTrees(oldText: IScriptSnapshot, newText: IScriptSnapshot, textChangeRange: TextChangeRange, expectedReusedElements: number, oldTree?: SourceFile): SourceFile {
+    function compareTrees(oldText: IScriptSnapshot, newText: IScriptSnapshot, textChangeRange: TextChangeRange, expectedReusedElements: number, oldTree?: SourceFile) {
         oldTree = oldTree || createTree(oldText, /*version:*/ ".");
         Utils.assertInvariants(oldTree, /*parent:*/ undefined);
 
@@ -76,7 +76,7 @@ namespace ts {
             assert.equal(actualReusedCount, expectedReusedElements, actualReusedCount + " !== " + expectedReusedElements);
         }
 
-        return incrementalNewTree;
+        return { oldTree, newTree, incrementalNewTree };
     }
 
     function reusedElements(oldNode: SourceFile, newNode: SourceFile): number {
@@ -103,7 +103,7 @@ namespace ts {
         for (let i = 0; i < repeat; i++) {
             const oldText = ScriptSnapshot.fromString(source);
             const newTextAndChange = withDelete(oldText, index, 1);
-            const newTree = compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, -1, oldTree);
+            const newTree = compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, -1, oldTree).incrementalNewTree;
 
             source = newTextAndChange.text.getText(0, newTextAndChange.text.getLength());
             oldTree = newTree;
@@ -116,7 +116,7 @@ namespace ts {
         for (let i = 0; i < repeat; i++) {
             const oldText = ScriptSnapshot.fromString(source);
             const newTextAndChange = withInsert(oldText, index + i, toInsert.charAt(i));
-            const newTree = compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, -1, oldTree);
+            const newTree = compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, -1, oldTree).incrementalNewTree;
 
             source = newTextAndChange.text.getText(0, newTextAndChange.text.getLength());
             oldTree = newTree;
@@ -639,7 +639,7 @@ module m3 { }\
         });
 
         it("Unterminated comment after keyword converted to identifier", () => {
-            // 'public' as a keyword should be incrementally unusable (because it has an 
+            // 'public' as a keyword should be incrementally unusable (because it has an
             // unterminated comment).  When we convert it to an identifier, that shouldn't
             // change anything, and we should still get the same errors.
             const source = "return; a.public /*";
@@ -796,6 +796,16 @@ module m3 { }\
             compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, 4);
         });
 
+        it("Reuse transformFlags of subtree during bind", () => {
+            const source = `class Greeter { constructor(element: HTMLElement) { } }`;
+            const oldText = ScriptSnapshot.fromString(source);
+            const newTextAndChange = withChange(oldText, 15, 0, "\n");
+            const { oldTree, incrementalNewTree } = compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, -1);
+            bindSourceFile(oldTree, {});
+            bindSourceFile(incrementalNewTree, {});
+            assert.equal(oldTree.transformFlags, incrementalNewTree.transformFlags);
+        });
+
         // Simulated typing tests.
 
         it("Type extends clause 1", () => {
diff --git a/src/services/services.ts b/src/services/services.ts
index 8abcf8f76846c..56e604abeb3eb 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -48,7 +48,6 @@ namespace ts {
         public jsDocComments: JSDoc[];
         public original: Node;
         public transformFlags: TransformFlags;
-        public excludeTransformFlags: TransformFlags;
         private _children: Node[];
 
         constructor(kind: SyntaxKind, pos: number, end: number) {
@@ -56,7 +55,6 @@ namespace ts {
             this.end = end;
             this.flags = NodeFlags.None;
             this.transformFlags = undefined;
-            this.excludeTransformFlags = undefined;
             this.parent = undefined;
             this.kind = kind;
         }

From 2bf38ab6cd6a2321b2422a503573d492115d3457 Mon Sep 17 00:00:00 2001
From: Mohamed Hegazy <mhegazy@microsoft.com>
Date: Mon, 7 Nov 2016 21:09:17 -0800
Subject: [PATCH 197/224] Port fix for
 https://github.com/Microsoft/TypeScript/issues/12069 (#12095)

---
 src/lib/dom.generated.d.ts       | 4 ++--
 src/lib/webworker.generated.d.ts | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/lib/dom.generated.d.ts b/src/lib/dom.generated.d.ts
index 9a87020d4f0db..fd77f369fd800 100644
--- a/src/lib/dom.generated.d.ts
+++ b/src/lib/dom.generated.d.ts
@@ -7586,7 +7586,7 @@ declare var IDBCursorWithValue: {
 
 interface IDBDatabase extends EventTarget {
     readonly name: string;
-    readonly objectStoreNames: string[];
+    readonly objectStoreNames: DOMStringList;
     onabort: (this: this, ev: Event) => any;
     onerror: (this: this, ev: ErrorEvent) => any;
     version: number;
@@ -7652,7 +7652,7 @@ declare var IDBKeyRange: {
 }
 
 interface IDBObjectStore {
-    readonly indexNames: string[];
+    readonly indexNames: DOMStringList;
     keyPath: string | string[];
     readonly name: string;
     readonly transaction: IDBTransaction;
diff --git a/src/lib/webworker.generated.d.ts b/src/lib/webworker.generated.d.ts
index 4aeba69630671..130510334d637 100644
--- a/src/lib/webworker.generated.d.ts
+++ b/src/lib/webworker.generated.d.ts
@@ -341,7 +341,7 @@ declare var IDBCursorWithValue: {
 
 interface IDBDatabase extends EventTarget {
     readonly name: string;
-    readonly objectStoreNames: string[];
+    readonly objectStoreNames: DOMStringList;
     onabort: (this: this, ev: Event) => any;
     onerror: (this: this, ev: ErrorEvent) => any;
     version: number;
@@ -407,7 +407,7 @@ declare var IDBKeyRange: {
 }
 
 interface IDBObjectStore {
-    readonly indexNames: string[];
+    readonly indexNames: DOMStringList;
     keyPath: string | string[];
     readonly name: string;
     readonly transaction: IDBTransaction;

From 9e3d6efb199520ac66529b933e549e432cd1776c Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Mon, 7 Nov 2016 21:13:11 -0800
Subject: [PATCH 198/224] reduce set of files being watched, increase polling
 interval (#12054) (#12092)

---
 src/compiler/program.ts                         |  7 ++++++-
 src/compiler/sys.ts                             | 10 +++++++---
 src/compiler/types.ts                           |  1 +
 src/server/project.ts                           | 12 +++++++++---
 src/server/types.d.ts                           |  2 +-
 src/server/typingsInstaller/typingsInstaller.ts |  2 +-
 src/server/utilities.ts                         |  2 +-
 src/services/jsTyping.ts                        |  2 +-
 8 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index dcb9cce0adb55..1b36d99d7c9d7 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -420,6 +420,7 @@ namespace ts {
             getTypeCount: () => getDiagnosticsProducingTypeChecker().getTypeCount(),
             getFileProcessingDiagnostics: () => fileProcessingDiagnostics,
             getResolvedTypeReferenceDirectives: () => resolvedTypeReferenceDirectives,
+            isSourceFileFromExternalLibrary,
             dropDiagnosticsProducingTypeChecker
         };
 
@@ -722,13 +723,17 @@ namespace ts {
                 getSourceFile: program.getSourceFile,
                 getSourceFileByPath: program.getSourceFileByPath,
                 getSourceFiles: program.getSourceFiles,
-                isSourceFileFromExternalLibrary: (file: SourceFile) => !!sourceFilesFoundSearchingNodeModules[file.path],
+                isSourceFileFromExternalLibrary,
                 writeFile: writeFileCallback || (
                     (fileName, data, writeByteOrderMark, onError, sourceFiles) => host.writeFile(fileName, data, writeByteOrderMark, onError, sourceFiles)),
                 isEmitBlocked,
             };
         }
 
+        function isSourceFileFromExternalLibrary(file: SourceFile): boolean {
+            return sourceFilesFoundSearchingNodeModules[file.path];
+        }
+
         function getDiagnosticsProducingTypeChecker() {
             return diagnosticsProducingTypeChecker || (diagnosticsProducingTypeChecker = createTypeChecker(program, /*produceDiagnostics:*/ true));
         }
diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index 9cf95d6de9b92..a1e82a66595b0 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -17,7 +17,11 @@ namespace ts {
         readFile(path: string, encoding?: string): string;
         getFileSize?(path: string): number;
         writeFile(path: string, data: string, writeByteOrderMark?: boolean): void;
-        watchFile?(path: string, callback: FileWatcherCallback): FileWatcher;
+        /**
+         * @pollingInterval - this parameter is used in polling-based watchers and ignored in watchers that 
+         * use native OS file watching
+         */
+        watchFile?(path: string, callback: FileWatcherCallback, pollingInterval?: number): FileWatcher;
         watchDirectory?(path: string, callback: DirectoryWatcherCallback, recursive?: boolean): FileWatcher;
         resolvePath(path: string): string;
         fileExists(path: string): boolean;
@@ -449,7 +453,7 @@ namespace ts {
                 },
                 readFile,
                 writeFile,
-                watchFile: (fileName, callback) => {
+                watchFile: (fileName, callback, pollingInterval) => {
                     if (useNonPollingWatchers) {
                         const watchedFile = watchedFileSet.addFile(fileName, callback);
                         return {
@@ -457,7 +461,7 @@ namespace ts {
                         };
                     }
                     else {
-                        _fs.watchFile(fileName, { persistent: true, interval: 250 }, fileChanged);
+                        _fs.watchFile(fileName, { persistent: true, interval: pollingInterval || 250 }, fileChanged);
                         return {
                             close: () => _fs.unwatchFile(fileName, fileChanged)
                         };
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 37a3cc466a0df..aa0b3e505f676 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2192,6 +2192,7 @@ namespace ts {
 
         /* @internal */ getFileProcessingDiagnostics(): DiagnosticCollection;
         /* @internal */ getResolvedTypeReferenceDirectives(): Map<ResolvedTypeReferenceDirective>;
+        /* @internal */ isSourceFileFromExternalLibrary(file: SourceFile): boolean;
         // For testing purposes only.
         /* @internal */ structureIsReused?: boolean;
     }
diff --git a/src/server/project.ts b/src/server/project.ts
index 563b045691071..d01df728248c6 100644
--- a/src/server/project.ts
+++ b/src/server/project.ts
@@ -301,7 +301,7 @@ namespace ts.server {
             return this.getLanguageService().getEmitOutput(info.fileName, emitOnlyDtsFiles);
         }
 
-        getFileNames() {
+        getFileNames(excludeFilesFromExternalLibraries?: boolean) {
             if (!this.program) {
                 return [];
             }
@@ -317,8 +317,14 @@ namespace ts.server {
                 }
                 return rootFiles;
             }
-            const sourceFiles = this.program.getSourceFiles();
-            return sourceFiles.map(sourceFile => asNormalizedPath(sourceFile.fileName));
+            const result: NormalizedPath[] = [];
+            for (const f of this.program.getSourceFiles()) {
+                if (excludeFilesFromExternalLibraries && this.program.isSourceFileFromExternalLibrary(f)) {
+                    continue;
+                }
+                result.push(asNormalizedPath(f.fileName));
+            }
+            return result;
         }
 
         getAllEmittableFiles() {
diff --git a/src/server/types.d.ts b/src/server/types.d.ts
index 95f9519cc388c..aebc312125203 100644
--- a/src/server/types.d.ts
+++ b/src/server/types.d.ts
@@ -73,6 +73,6 @@ declare namespace ts.server {
     export interface InstallTypingHost extends JsTyping.TypingResolutionHost {
         writeFile(path: string, content: string): void;
         createDirectory(path: string): void;
-        watchFile?(path: string, callback: FileWatcherCallback): FileWatcher;
+        watchFile?(path: string, callback: FileWatcherCallback, pollingInterval?: number): FileWatcher;
     }
 }
\ No newline at end of file
diff --git a/src/server/typingsInstaller/typingsInstaller.ts b/src/server/typingsInstaller/typingsInstaller.ts
index a602a9f1a26c8..da97dbcd194df 100644
--- a/src/server/typingsInstaller/typingsInstaller.ts
+++ b/src/server/typingsInstaller/typingsInstaller.ts
@@ -367,7 +367,7 @@ namespace ts.server.typingsInstaller {
                         this.sendResponse({ projectName: projectName, kind: server.ActionInvalidate });
                         isInvoked = true;
                     }
-                });
+                }, /*pollingInterval*/ 2000);
                 watchers.push(w);
             }
             this.projectWatchers[projectName] = watchers;
diff --git a/src/server/utilities.ts b/src/server/utilities.ts
index 9a832d22c8d5c..ac80965211923 100644
--- a/src/server/utilities.ts
+++ b/src/server/utilities.ts
@@ -50,7 +50,7 @@ namespace ts.server {
     export function createInstallTypingsRequest(project: Project, typingOptions: TypingOptions, unresolvedImports: SortedReadonlyArray<string>, cachePath?: string): DiscoverTypings {
         return {
             projectName: project.getProjectName(),
-            fileNames: project.getFileNames(),
+            fileNames: project.getFileNames(/*excludeFilesFromExternalLibraries*/ true),
             compilerOptions: project.getCompilerOptions(),
             typingOptions,
             unresolvedImports,
diff --git a/src/services/jsTyping.ts b/src/services/jsTyping.ts
index 0f635c151740a..316dcd355c232 100644
--- a/src/services/jsTyping.ts
+++ b/src/services/jsTyping.ts
@@ -88,7 +88,7 @@ namespace ts.JsTyping {
         exclude = typingOptions.exclude || [];
 
         const possibleSearchDirs = map(fileNames, getDirectoryPath);
-        if (projectRootPath !== undefined) {
+        if (projectRootPath) {
             possibleSearchDirs.push(projectRootPath);
         }
         searchDirs = deduplicate(possibleSearchDirs);

From 84f8f8bba89ff459180852179c31ea7e9105736d Mon Sep 17 00:00:00 2001
From: Mohamed Hegazy <mhegazy@microsoft.com>
Date: Mon, 7 Nov 2016 21:58:53 -0800
Subject: [PATCH 199/224] Update authors for release-2.1

---
 .mailmap   | 43 ++++++++++++++++++++++++++++++++++++-------
 AUTHORS.md | 32 +++++++++++++++++++++++++++++++-
 2 files changed, 67 insertions(+), 8 deletions(-)

diff --git a/.mailmap b/.mailmap
index e66f669b8ee9a..cc101c0517e83 100644
--- a/.mailmap
+++ b/.mailmap
@@ -1,32 +1,38 @@
 
-Alexander <alexander@kuvaev.me># Alexander Kuvaev
 AbubakerB <abubaker_bashir@hotmail.com> # Abubaker Bashir
+Alexander <alexander@kuvaev.me># Alexander Kuvaev
 Adam Freidin <adam.freidin@gmail.com> Adam Freidin <afreidin@adobe.com>
 Adi Dahiya <adahiya@palantir.com> Adi Dahiya <adi.dahiya14@gmail.com>
 Ahmad Farid <ahfarid@microsoft.com> ahmad-farid <ahfarid@microsoft.com>
+Alexander Rusakov  <a_s_rusakov@mail.ru>
 Alex Eagle <alexeagle@google.com>
+Anatoly Ressin  <anatoly.ressin@icloud.com>
 Anders Hejlsberg <andersh@microsoft.com> unknown <andersh@AndersX1.NOE.Nokia.com> unknown <andersh@andersh-yoga.redmond.corp.microsoft.com>
+Andrej Baran  <andrej.baran@gmail.com>
 Andrew Z Allen <me@andrewzallen.com>
 Andy Hanson <anhans@microsoft.com> Andy <anhans@microsoft.com>
 Anil Anar <anilanar@hotmail.com>
 Anton Tolmachev <myste@mail.ru>
 Arnavion <arnavion@gmail.com> # Arnav Singh
-Arthur Ozga <aozgaa@umich.edu> Arthur Ozga <t-arthoz@microsoft.com>
+Arthur Ozga <aozgaa@umich.edu> Arthur Ozga <t-arthoz@microsoft.com> Arthur Ozga  <aozgaa-ms@outlook.com> Arthur Ozga  <aozgaa@users.noreply.github.com> Arthur Ozga  <arozga@microsoft.com>
 Asad Saeeduddin <masaeedu@gmail.com>
 Schmavery <avery.schmavery@gmail.com> # Avery Morin
 Basarat Ali Syed <basaratali@gmail.com> Basarat Syed <basaratali@gmail.com> basarat <basaratali@gmail.com>
 Bill Ticehurst <billti@hotmail.com> Bill Ticehurst <billti@microsoft.com>
 Ben Duffield <jebavarde@gmail.com>
+Ben Mosher  <me@benmosher.com>
 Blake Embrey <hello@blakeembrey.com>
 Bowden Kelly <wilkelly@microsoft.com>
 Brett Mayen <bmayen@midnightsnacks.net>
 Bryan Forbes <bryan@reigndropsfall.net>
 Caitlin Potter <caitpotter88@gmail.com>
 ChrisBubernak <chris.bubernak@gmail.com> unknown <chrbub@chrbub1.redmond.corp.microsoft.com> # Chris Bubernak
+Christophe Vidal  <kriss@krizalys.com>
 Chuck Jazdzewski <chuckj@google.com>
 Colby Russell <mr@colbyrussell.com>
 Colin Snover <github.com@zetafleet.com>
 Cyrus Najmabadi <cyrusn@microsoft.com> CyrusNajmabadi <cyrusn@microsoft.com> unknown <cyrusn@cylap.ntdev.corp.microsoft.com>
+Dafrok  <o.o@mug.dog> # Dafrok Zhang
 Dan Corder <dev@dancorder.com>
 Dan Quirk <danquirk@microsoft.com> Dan Quirk <danquirk@users.noreply.github.com> nknown <danquirk@DANQUIRK1.redmond.corp.microsoft.com>
 Daniel Rosenwasser <drosen@microsoft.com> Daniel Rosenwasser <DanielRosenwasser@users.noreply.github.com> Daniel Rosenwasser <DanielRosenwasser@gmail.com> Daniel Rosenwasser <Daniel.Rosenwasser@microsoft.com> Daniel Rosenwasser <DanielRosenwasser@microsoft.com>
@@ -36,17 +42,22 @@ Denis Nedelyaev <denvned@gmail.com>
 Dick van den Brink <d_vandenbrink@outlook.com> unknown <d_vandenbrink@outlook.com> unknown <d_vandenbrink@live.com>
 Dirk Baeumer <dirkb@microsoft.com> Dirk Bäumer <dirkb@microsoft.com> # Dirk Bäumer
 Dirk Holtwick <dirk.holtwick@gmail.com>
+Dom Chen  <domchen@users.noreply.github.com>
 Doug Ilijev <dilijev@users.noreply.github.com>
 Erik Edrosa <erik.edrosa@gmail.com>
+erictsangx  <erictsangx@gmail.com> # Eric Tsang
 Ethan Rubio <ethanrubio@users.noreply.github.com>
 Evan Martin <martine@danga.com>
 Evan Sebastian <evanlhoini@gmail.com>
 Eyas <eyas.sharaiha@gmail.com> # Eyas Sharaiha
+Fabian Cook  <faybecook@gmail.com>
 falsandtru <falsandtru@users.noreply.github.com> # @falsandtru
 Frank Wallis <fwallis@outlook.com>
-František Žiačik <fziacik@gratex.com> František Žiačik <ziacik@gmail.com>
+František Žiacik <fziacik@gratex.com> František Žiacik <ziacik@gmail.com>
+Gabe Moothart  <gmoothart@gmail.com>
 Gabriel Isenberg <gisenberg@gmail.com>
 Gilad Peleg <giladp007@gmail.com>
+Godfrey Chan  <godfreykfc@gmail.com>
 Graeme Wicksted <graeme.wicksted@gmail.com>
 Guillaume Salles <guillaume.salles@me.com>
 Guy Bedford <guybedford@gmail.com> guybedford <guybedford@gmail.com>
@@ -55,6 +66,7 @@ Iain Monro <iain.monro@softwire.com>
 Ingvar Stepanyan <me@rreverser.com>
 impinball <impinball@gmail.com> # Isiah Meadows
 Ivo Gabe de Wolff <ivogabe@ivogabe.nl>
+Jakub Młokosiewicz  <hckr@users.noreply.github.com>
 James Whitney <james@whitney.io>
 Jason Freeman <jfreeman@microsoft.com> Jason Freeman <JsonFreeman@users.noreply.github.com>
 Jason Killian <jkillian@palantir.com>
@@ -69,11 +81,14 @@ Jonathan Park <jpark@daptiv.com>
 Jonathan Turner <jont@microsoft.com> Jonathan Turner <probata@hotmail.com>
 Jonathan Toland <toland@dnalot.com>
 Jesse Schalken <me@jesseschalken.com>
+Josh Abernathy  <joshaber@gmail.com> joshaber  <joshaber@gmail.com>
 Josh Kalderimis <josh.kalderimis@gmail.com>
 Josh Soref <jsoref@users.noreply.github.com>
 Juan Luis Boya García <ntrrgc@gmail.com>
 Julian Williams <julianjw92@gmail.com>
-Herrington Darkholme <nonamesheep1@gmail.com>
+Justin Bay  <justin.bay@outlook.com>
+Justin Johansson  <thebabellion@gmail.com>
+Herrington Darkholme <nonamesheep1@gmail.com> (´·?·`)  <HerringtonDarkholme@users.noreply.github.com> # Herrington Darkholme
 Kagami Sascha Rosylight <saschanaz@outlook.com> SaschaNaz <saschanaz@outlook.com>
 Kanchalai Tanglertsampan <yuisu@microsoft.com> Yui <yuit@users.noreply.github.com>
 Kanchalai Tanglertsampan <yuisu@microsoft.com> Yui T <yuisu@microsoft.com>
@@ -82,23 +97,29 @@ Kanchalai Tanglertsampan <yuisu@microsoft.com> Yui <yuisu@microsoft.com>
 Kanchalai Tanglertsampan <yuisu@microsoft.com> yui T <yuisu@microsoft.com>
 Keith Mashinter <kmashint@yahoo.com> kmashint <kmashint@yahoo.com>
 Ken Howard <ken@simplicatedweb.com>
+Kevin Lang  <klang2012@gmail.com>
 kimamula <kenji.imamula@gmail.com> # Kenji Imamula
 Kyle Kelley <rgbkrk@gmail.com>
 Lorant Pinter <lorant.pinter@prezi.com>
 Lucien Greathouse <me@lpghatguy.com>
+Lukas Elmer  <lukas.elmer@gmail.com> Lukas Elmer  <lukas.elmer@renuo.ch>
 Martin Vseticka <vseticka.martin@gmail.com> Martin Všeticka <vseticka.martin@gmail.com> MartyIX <vseticka.martin@gmail.com>
+gcnew  <gcnew@abv.bg> # Marin Marinov
 vvakame <vvakame+dev@gmail.com> # Masahiro Wakame
 Matt McCutchen <rmccutch@mit.edu>
 Max Deepfield <maxdeepfield@absolutefreakout.com>
 Micah Zoltu <micah@zoltu.net>
+Michael  <maykelchiche@gmail.com>
 Mohamed Hegazy <mhegazy@microsoft.com>
 Nathan Shively-Sanders <nathansa@microsoft.com>
 Nathan Yee <ny.nathan.yee@gmail.com>
 Nima Zahedi <nima.zahedee@gmail.com>
+Noah Chen  <nchen@palantir.com>
 Noj Vek <nojvek@gmail.com>
 mihailik <mihailik@gmail.com> # Oleg Mihailik
 Oleksandr Chekhovskyi <oleksandr.chekhovskyi@hansoft.com>
 Paul van Brenk <paul.van.brenk@microsoft.com> Paul van Brenk <paul.van.brenk@outlook.com> unknown <paul.van.brenk@microsoft.com> unknown <paul.van.brenk@microsoft.com>	unknown <pvanbren@pvbvsproai.redmond.corp.microsoft.com>
+Omer Sheikh  <ojsheikh@gmail.com>
 Oskar Segersva¨rd <oskar.segersvard@widespace.com>
 pcan <piero.cangianiello@gmail.com> # Piero Cangianiello
 pcbro <2bux89+dk3zspjmuh16o@sharklasers.com> # @pcbro
@@ -109,21 +130,26 @@ progre <djyayutto@gmail.com> # @progre
 Prayag Verma <prayag.verma@gmail.com>
 Punya Biswal <pbiswal@palantir.com>
 Rado Kirov <radokirov@google.com>
-Ron Buckton <rbuckton@microsoft.com> Ron Buckton <ron.buckton@microsoft.com>
+Ron Buckton <rbuckton@microsoft.com> Ron Buckton <ron.buckton@microsoft.com> rbuckton  <rbuckton@chronicles.org>
+Rostislav Galimsky  <rostgal@gmail.com>
 Richard Knoll <riknoll@users.noreply.github.com> Richard Knoll <riknoll@microsoft.com>
 Rowan Wyborn <rwyborn@internode.on.net>
 Ryan Cavanaugh <RyanCavanaugh@users.noreply.github.com> Ryan Cavanaugh <ryan.cavanaugh@microsoft.com> Ryan Cavanaugh <ryanca@microsoft.com>
 Ryohei Ikegami <iofg2100@gmail.com>
 Sarangan Rajamanickam <sarajama@microsoft.com>
 Sébastien Arod <sebastien.arod@gmail.com>
+Sergey Shandar  <sergey-shandar@users.noreply.github.com>
 Sheetal Nandi <shkamat@microsoft.com>
 Shengping Zhong <zhongsp@users.noreply.github.com>
 shyyko.serhiy@gmail.com <shyyko.serhiy@gmail.com> # Shyyko Serhiy
+Sam El-Husseini  <samelh@microsoft.com>
 Simon Hürlimann <simon.huerlimann@cyt.ch>
+Slawomir Sadziak  <slsadzia@microsoft.com>
 Solal Pirelli <solal.pirelli@gmail.com>
 Stan Thomas <stmsdn@norvil.net>
 Stanislav Sysoev <d4rkr00t@gmail.com>
 Steve Lucco <steveluc@users.noreply.github.com> steveluc <steveluc@microsoft.com>
+Sudheesh Singanamalla  <sudheesh1995@outlook.com>
 Tarik <tarik@pushmote.com> # Tarik Ozket
 Tetsuharu OHZEKI <saneyuki.snyk@gmail.com> # Tetsuharu Ohzeki
 Tien Nguyen <tihoanh@microsoft.com> tien <hoanhtien@users.noreply.github.com> unknown <tihoanh@microsoft.com> #Tien Hoanhtien
@@ -133,6 +159,7 @@ Tingan Ho <tingan87@gmail.com>
 togru <v3nomzxgt8@gmail.com> # togru
 Tomas Grubliauskas <tgrubliauskas@gmail.com>
 ToddThomson <achilles@telus.net> # Todd Thomson
+Torben Fitschen  <torben.fitschen@mayflower.de>
 TruongSinh Tran-Nguyen <i@truongsinh.pro>
 vilicvane <i@vilic.info> # Vilic Vane
 Vladimir Matveev <vladima@microsoft.com> vladima <vladima@microsoft.com> v2m <desco.by@gmail.com>
@@ -140,7 +167,9 @@ Wesley Wigham <t-weswig@microsoft.com> Wesley Wigham <wwigham@gmail.com>
 York Yao <plantain-00@users.noreply.github.com> york yao <yaoao12306@outlook.com> yaoyao <yaoyao12306@163.com>
 Yuichi Nukiyama <oscar.wilde84@hotmail.co.jp> YuichiNukiyama <oscar.wilde84@hotmail.co.jp>
 Zev Spitz <shivisi@etrog.net.il>
-Zhengbo Li <zhengbli@microsoft.com> zhengbli <zhengbli@microsoft.com> Zhengbo Li <Zhengbo Li> Zhengbo Li <zhengbli@mirosoft.com> tinza123 <li.zhengbo@outlook.com> unknown <zhengbli@zhengblit430.redmond.corp.microsoft.com> Zhengbo Li <Zhengbo Li>
+Zhengbo Li <zhengbli@microsoft.com> zhengbli <zhengbli@microsoft.com> Zhengbo Li <Zhengbo Li> Zhengbo Li <zhengbli@mirosoft.com> tinza123 <li.zhengbo@outlook.com> unknown <zhengbli@zhengblit430.redmond.corp.microsoft.com> Zhengbo Li <Zhengbo Li> zhengbli  <zhengli@microsoft.com>
 zhongsp <patrick.zhongsp@gmail.com> # Patrick Zhong
 T18970237136 <T18970237136@users.noreply.github.com> # @T18970237136
-JBerger <JBerger@melco.com>
\ No newline at end of file
+JBerger <JBerger@melco.com>
+bootstraponline  <code@bootstraponline.com> # @bootstraponline
+yortus  <yortus@gmail.com> # @yortus
\ No newline at end of file
diff --git a/AUTHORS.md b/AUTHORS.md
index 08039127d9db0..50f1ea12c2b17 100644
--- a/AUTHORS.md
+++ b/AUTHORS.md
@@ -5,7 +5,10 @@ TypeScript is authored by:
 * Ahmad Farid
 * Alex Eagle
 * Alexander Kuvaev
+* Alexander Rusakov 
+* Anatoly Ressin 
 * Anders Hejlsberg
+* Andrej Baran 
 * Andrew Z Allen
 * Andy Hanson
 * Anil Anar
@@ -16,17 +19,21 @@ TypeScript is authored by:
 * Avery Morin
 * Basarat Ali Syed
 * Ben Duffield
+* Ben Mosher 
 * Bill Ticehurst
 * Blake Embrey
+* @bootstraponline
 * Bowden Kelly
 * Brett Mayen
 * Bryan Forbes
 * Caitlin Potter
 * Chris Bubernak
+* Christophe Vidal 
 * Chuck Jazdzewski
 * Colby Russell
 * Colin Snover
 * Cyrus Najmabadi
+* Dafrok Zhang
 * Dan Corder
 * Dan Quirk
 * Daniel Rosenwasser
@@ -36,17 +43,22 @@ TypeScript is authored by:
 * Dick van den Brink
 * Dirk Bäumer
 * Dirk Holtwick
+* Dom Chen 
 * Doug Ilijev
+* Eric Tsang
 * Erik Edrosa
 * Ethan Rubio
 * Evan Martin
 * Evan Sebastian
 * Eyas Sharaiha
+* Fabian Cook 
 * @falsandtru
 * Frank Wallis
-* František Žiačik
+* František Žiacik
+* Gabe Moothart 
 * Gabriel Isenberg
 * Gilad Peleg
+* Godfrey Chan 
 * Graeme Wicksted
 * Guillaume Salles
 * Guy Bedford
@@ -56,6 +68,7 @@ TypeScript is authored by:
 * Ingvar Stepanyan
 * Isiah Meadows
 * Ivo Gabe de Wolff
+* Jakub Młokosiewicz 
 * James Whitney
 * Jason Freeman
 * Jason Killian
@@ -71,30 +84,39 @@ TypeScript is authored by:
 * Jonathan Park
 * Jonathan Toland
 * Jonathan Turner
+* Josh Abernathy 
 * Josh Kalderimis
 * Josh Soref
 * Juan Luis Boya García
 * Julian Williams
+* Justin Bay 
+* Justin Johansson 
 * Kagami Sascha Rosylight
 * Kanchalai Tanglertsampan
 * Keith Mashinter
 * Ken Howard
 * Kenji Imamula
+* Kevin Lang 
 * Kyle Kelley
 * Lorant Pinter
 * Lucien Greathouse
+* Lukas Elmer 
+* Marin Marinov
 * Martin Vseticka
 * Masahiro Wakame
 * Matt McCutchen
 * Max Deepfield
 * Micah Zoltu
+* Michael 
 * Mohamed Hegazy
 * Nathan Shively-Sanders
 * Nathan Yee
 * Nima Zahedi
+* Noah Chen 
 * Noj Vek
 * Oleg Mihailik
 * Oleksandr Chekhovskyi
+* Omer Sheikh 
 * Oskar Segersva¨rd
 * Patrick Zhong
 * Paul van Brenk
@@ -109,21 +131,27 @@ TypeScript is authored by:
 * Rado Kirov
 * Richard Knoll
 * Ron Buckton
+* Rostislav Galimsky 
 * Rowan Wyborn
 * Ryan Cavanaugh
 * Ryohei Ikegami
+* Sam El-Husseini 
 * Sarangan Rajamanickam
+* Sergey Shandar 
 * Sheetal Nandi
 * Shengping Zhong
 * Shyyko Serhiy
 * Simon Hürlimann
+* Slawomir Sadziak 
 * Solal Pirelli
 * Stan Thomas
 * Stanislav Sysoev
 * Steve Lucco
+* Sudheesh Singanamalla 
 * Sébastien Arod
 * @T18970237136
 * Tarik Ozket
+* Tetsuharu Ohzeki
 * Tien Hoanhtien
 * Tim Perry
 * Tim Viiding-Spader
@@ -131,11 +159,13 @@ TypeScript is authored by:
 * Todd Thomson
 * togru
 * Tomas Grubliauskas
+* Torben Fitschen 
 * TruongSinh Tran-Nguyen
 * Vilic Vane
 * Vladimir Matveev
 * Wesley Wigham
 * York Yao
+* @yortus
 * Yuichi Nukiyama
 * Zev Spitz
 * Zhengbo Li
\ No newline at end of file

From be0358cc0cff88b0e5b05e656735da80a052c0f6 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Tue, 8 Nov 2016 06:09:41 -0800
Subject: [PATCH 200/224] Include declaration file emit

---
 .../reference/instantiatedTypeAliasDisplay.js | 15 ++++
 .../instantiatedTypeAliasDisplay.symbols      | 75 ++++++++++---------
 .../instantiatedTypeAliasDisplay.types        |  1 +
 .../compiler/instantiatedTypeAliasDisplay.ts  |  2 +
 4 files changed, 56 insertions(+), 37 deletions(-)

diff --git a/tests/baselines/reference/instantiatedTypeAliasDisplay.js b/tests/baselines/reference/instantiatedTypeAliasDisplay.js
index 86b17262e0f06..9c2b91b613e23 100644
--- a/tests/baselines/reference/instantiatedTypeAliasDisplay.js
+++ b/tests/baselines/reference/instantiatedTypeAliasDisplay.js
@@ -1,4 +1,5 @@
 //// [instantiatedTypeAliasDisplay.ts]
+
 // Repros from #12066
 
 interface X<A> {
@@ -19,3 +20,17 @@ const x2 = f2({}, {}, {}, {});  // Z<{}, string[]>
 // Repros from #12066
 var x1 = f1(); // Z<string, number>
 var x2 = f2({}, {}, {}, {}); // Z<{}, string[]>
+
+
+//// [instantiatedTypeAliasDisplay.d.ts]
+interface X<A> {
+    a: A;
+}
+interface Y<B> {
+    b: B;
+}
+declare type Z<A, B> = X<A> | Y<B>;
+declare function f1<A>(): Z<A, number>;
+declare function f2<A, B, C, D, E>(a: A, b: B, c: C, d: D): Z<A, string[]>;
+declare const x1: Z<string, number>;
+declare const x2: Z<{}, string[]>;
diff --git a/tests/baselines/reference/instantiatedTypeAliasDisplay.symbols b/tests/baselines/reference/instantiatedTypeAliasDisplay.symbols
index 3c6f7d2b725c7..fa8140cfcd731 100644
--- a/tests/baselines/reference/instantiatedTypeAliasDisplay.symbols
+++ b/tests/baselines/reference/instantiatedTypeAliasDisplay.symbols
@@ -1,60 +1,61 @@
 === tests/cases/compiler/instantiatedTypeAliasDisplay.ts ===
+
 // Repros from #12066
 
 interface X<A> {
 >X : Symbol(X, Decl(instantiatedTypeAliasDisplay.ts, 0, 0))
->A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 2, 12))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 3, 12))
 
     a: A;
->a : Symbol(X.a, Decl(instantiatedTypeAliasDisplay.ts, 2, 16))
->A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 2, 12))
+>a : Symbol(X.a, Decl(instantiatedTypeAliasDisplay.ts, 3, 16))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 3, 12))
 }
 interface Y<B> {
->Y : Symbol(Y, Decl(instantiatedTypeAliasDisplay.ts, 4, 1))
->B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 5, 12))
+>Y : Symbol(Y, Decl(instantiatedTypeAliasDisplay.ts, 5, 1))
+>B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 6, 12))
 
     b: B;
->b : Symbol(Y.b, Decl(instantiatedTypeAliasDisplay.ts, 5, 16))
->B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 5, 12))
+>b : Symbol(Y.b, Decl(instantiatedTypeAliasDisplay.ts, 6, 16))
+>B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 6, 12))
 }
 type Z<A, B> = X<A> | Y<B>;
->Z : Symbol(Z, Decl(instantiatedTypeAliasDisplay.ts, 7, 1))
->A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 8, 7))
->B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 8, 9))
+>Z : Symbol(Z, Decl(instantiatedTypeAliasDisplay.ts, 8, 1))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 9, 7))
+>B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 9, 9))
 >X : Symbol(X, Decl(instantiatedTypeAliasDisplay.ts, 0, 0))
->A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 8, 7))
->Y : Symbol(Y, Decl(instantiatedTypeAliasDisplay.ts, 4, 1))
->B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 8, 9))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 9, 7))
+>Y : Symbol(Y, Decl(instantiatedTypeAliasDisplay.ts, 5, 1))
+>B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 9, 9))
 
 declare function f1<A>(): Z<A, number>;
->f1 : Symbol(f1, Decl(instantiatedTypeAliasDisplay.ts, 8, 27))
->A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 10, 20))
->Z : Symbol(Z, Decl(instantiatedTypeAliasDisplay.ts, 7, 1))
->A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 10, 20))
-
-declare function f2<A, B, C, D, E>(a: A, b: B, c: C, d: D): Z<A, string[]>;
->f2 : Symbol(f2, Decl(instantiatedTypeAliasDisplay.ts, 10, 39))
+>f1 : Symbol(f1, Decl(instantiatedTypeAliasDisplay.ts, 9, 27))
 >A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 11, 20))
->B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 11, 22))
->C : Symbol(C, Decl(instantiatedTypeAliasDisplay.ts, 11, 25))
->D : Symbol(D, Decl(instantiatedTypeAliasDisplay.ts, 11, 28))
->E : Symbol(E, Decl(instantiatedTypeAliasDisplay.ts, 11, 31))
->a : Symbol(a, Decl(instantiatedTypeAliasDisplay.ts, 11, 35))
->A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 11, 20))
->b : Symbol(b, Decl(instantiatedTypeAliasDisplay.ts, 11, 40))
->B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 11, 22))
->c : Symbol(c, Decl(instantiatedTypeAliasDisplay.ts, 11, 46))
->C : Symbol(C, Decl(instantiatedTypeAliasDisplay.ts, 11, 25))
->d : Symbol(d, Decl(instantiatedTypeAliasDisplay.ts, 11, 52))
->D : Symbol(D, Decl(instantiatedTypeAliasDisplay.ts, 11, 28))
->Z : Symbol(Z, Decl(instantiatedTypeAliasDisplay.ts, 7, 1))
+>Z : Symbol(Z, Decl(instantiatedTypeAliasDisplay.ts, 8, 1))
 >A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 11, 20))
 
+declare function f2<A, B, C, D, E>(a: A, b: B, c: C, d: D): Z<A, string[]>;
+>f2 : Symbol(f2, Decl(instantiatedTypeAliasDisplay.ts, 11, 39))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 12, 20))
+>B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 12, 22))
+>C : Symbol(C, Decl(instantiatedTypeAliasDisplay.ts, 12, 25))
+>D : Symbol(D, Decl(instantiatedTypeAliasDisplay.ts, 12, 28))
+>E : Symbol(E, Decl(instantiatedTypeAliasDisplay.ts, 12, 31))
+>a : Symbol(a, Decl(instantiatedTypeAliasDisplay.ts, 12, 35))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 12, 20))
+>b : Symbol(b, Decl(instantiatedTypeAliasDisplay.ts, 12, 40))
+>B : Symbol(B, Decl(instantiatedTypeAliasDisplay.ts, 12, 22))
+>c : Symbol(c, Decl(instantiatedTypeAliasDisplay.ts, 12, 46))
+>C : Symbol(C, Decl(instantiatedTypeAliasDisplay.ts, 12, 25))
+>d : Symbol(d, Decl(instantiatedTypeAliasDisplay.ts, 12, 52))
+>D : Symbol(D, Decl(instantiatedTypeAliasDisplay.ts, 12, 28))
+>Z : Symbol(Z, Decl(instantiatedTypeAliasDisplay.ts, 8, 1))
+>A : Symbol(A, Decl(instantiatedTypeAliasDisplay.ts, 12, 20))
+
 const x1 = f1<string>();  // Z<string, number>
->x1 : Symbol(x1, Decl(instantiatedTypeAliasDisplay.ts, 13, 5))
->f1 : Symbol(f1, Decl(instantiatedTypeAliasDisplay.ts, 8, 27))
+>x1 : Symbol(x1, Decl(instantiatedTypeAliasDisplay.ts, 14, 5))
+>f1 : Symbol(f1, Decl(instantiatedTypeAliasDisplay.ts, 9, 27))
 
 const x2 = f2({}, {}, {}, {});  // Z<{}, string[]>
->x2 : Symbol(x2, Decl(instantiatedTypeAliasDisplay.ts, 14, 5))
->f2 : Symbol(f2, Decl(instantiatedTypeAliasDisplay.ts, 10, 39))
+>x2 : Symbol(x2, Decl(instantiatedTypeAliasDisplay.ts, 15, 5))
+>f2 : Symbol(f2, Decl(instantiatedTypeAliasDisplay.ts, 11, 39))
 
diff --git a/tests/baselines/reference/instantiatedTypeAliasDisplay.types b/tests/baselines/reference/instantiatedTypeAliasDisplay.types
index 44885777e7483..89320e1dba6f1 100644
--- a/tests/baselines/reference/instantiatedTypeAliasDisplay.types
+++ b/tests/baselines/reference/instantiatedTypeAliasDisplay.types
@@ -1,4 +1,5 @@
 === tests/cases/compiler/instantiatedTypeAliasDisplay.ts ===
+
 // Repros from #12066
 
 interface X<A> {
diff --git a/tests/cases/compiler/instantiatedTypeAliasDisplay.ts b/tests/cases/compiler/instantiatedTypeAliasDisplay.ts
index d2abaaf8afe96..8f7500e7830be 100644
--- a/tests/cases/compiler/instantiatedTypeAliasDisplay.ts
+++ b/tests/cases/compiler/instantiatedTypeAliasDisplay.ts
@@ -1,3 +1,5 @@
+// @declaration: true
+
 // Repros from #12066
 
 interface X<A> {

From 9a9f45f0fbafebb0b52b524db8448d8330c5984b Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Tue, 8 Nov 2016 15:32:53 -0800
Subject: [PATCH 201/224] use createHash from ServerHost instead of explicit
 require (#12043)

* use createHash from ServerHost instead of explicit require

* added missing method in ServerHost stub
---
 src/harness/harnessLanguageService.ts          |  4 ++++
 src/harness/unittests/cachingInServerLSHost.ts |  3 ++-
 src/harness/unittests/session.ts               |  3 ++-
 src/harness/unittests/tsserverProjectSystem.ts |  4 ++++
 src/server/builder.ts                          | 13 +------------
 src/server/editorServices.ts                   |  2 ++
 6 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/src/harness/harnessLanguageService.ts b/src/harness/harnessLanguageService.ts
index 889d4f28ce9a9..a49f89267299f 100644
--- a/src/harness/harnessLanguageService.ts
+++ b/src/harness/harnessLanguageService.ts
@@ -720,6 +720,10 @@ namespace Harness.LanguageService {
         clearImmediate(timeoutId: any): void {
             clearImmediate(timeoutId);
         }
+
+        createHash(s: string) {
+            return s;
+        }
     }
 
     export class ServerLanguageServiceAdapter implements LanguageServiceAdapter {
diff --git a/src/harness/unittests/cachingInServerLSHost.ts b/src/harness/unittests/cachingInServerLSHost.ts
index 1100bb3663b59..4286d3555d883 100644
--- a/src/harness/unittests/cachingInServerLSHost.ts
+++ b/src/harness/unittests/cachingInServerLSHost.ts
@@ -43,7 +43,8 @@ namespace ts {
             setTimeout,
             clearTimeout,
             setImmediate: typeof setImmediate !== "undefined" ? setImmediate : action => setTimeout(action, 0),
-            clearImmediate: typeof clearImmediate !== "undefined" ? clearImmediate : clearTimeout
+            clearImmediate: typeof clearImmediate !== "undefined" ? clearImmediate : clearTimeout,
+            createHash: s => s
         };
     }
 
diff --git a/src/harness/unittests/session.ts b/src/harness/unittests/session.ts
index 05f62c4b9f622..8800e84474bbd 100644
--- a/src/harness/unittests/session.ts
+++ b/src/harness/unittests/session.ts
@@ -24,7 +24,8 @@ namespace ts.server {
         setTimeout() { return 0; },
         clearTimeout: noop,
         setImmediate: () => 0,
-        clearImmediate: noop
+        clearImmediate: noop,
+        createHash: s => s
     };
     const nullCancellationToken: HostCancellationToken = { isCancellationRequested: () => false };
     const mockLogger: Logger = {
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index 62c0957d6a37e..17b1dd3e585f7 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -434,6 +434,10 @@ namespace ts.projectSystem {
             };
         }
 
+        createHash(s: string): string {
+            return s;
+        }
+
         triggerDirectoryWatcherCallback(directoryName: string, fileName: string): void {
             const path = this.toPath(directoryName);
             const callbacks = this.watchedDirectories[path];
diff --git a/src/server/builder.ts b/src/server/builder.ts
index 548a3ac854c0e..5354e7ed50838 100644
--- a/src/server/builder.ts
+++ b/src/server/builder.ts
@@ -5,15 +5,6 @@
 
 namespace ts.server {
 
-    interface Hash {
-        update(data: any, input_encoding?: string): Hash;
-        digest(encoding: string): any;
-    }
-
-    const crypto: {
-        createHash(algorithm: string): Hash
-    } = require("crypto");
-
     export function shouldEmitFile(scriptInfo: ScriptInfo) {
         return !scriptInfo.hasMixedContent;
     }
@@ -49,9 +40,7 @@ namespace ts.server {
         }
 
         private computeHash(text: string): string {
-            return crypto.createHash("md5")
-                .update(text)
-                .digest("base64");
+            return this.project.projectService.host.createHash(text);
         }
 
         private getSourceFile(): SourceFile {
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index 269eea064647d..d7dcfc810b47e 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -250,6 +250,8 @@ namespace ts.server {
             readonly typingsInstaller: ITypingsInstaller = nullTypingsInstaller,
             private readonly eventHandler?: ProjectServiceEventHandler) {
 
+            Debug.assert(!!host.createHash, "'ServerHost.createHash' is required for ProjectService");
+
             this.toCanonicalFileName = createGetCanonicalFileName(host.useCaseSensitiveFileNames);
             this.directoryWatchers = new DirectoryWatchers(this);
             this.throttledOperations = new ThrottledOperations(host);

From 28cc9385035a65f5dcd74a4f9b47e7022678302f Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Tue, 8 Nov 2016 16:10:34 -0800
Subject: [PATCH 202/224] (signature help) type parameter lists are never
 variadic (#12112)

---
 src/harness/fourslash.ts                               | 10 +++++++++-
 src/services/signatureHelp.ts                          |  5 ++++-
 tests/cases/fourslash/fourslash.ts                     |  1 +
 .../signatureHelpTypeParametersNotVariadic.ts          |  8 ++++++++
 4 files changed, 22 insertions(+), 2 deletions(-)
 create mode 100644 tests/cases/fourslash/signatureHelpTypeParametersNotVariadic.ts

diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index ae32fe3db1631..6ff4dccdee30e 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -1026,7 +1026,7 @@ namespace FourSlash {
                 ts.displayPartsToString(help.suffixDisplayParts), expected);
         }
 
-        public verifyCurrentParameterIsletiable(isVariable: boolean) {
+        public verifyCurrentParameterIsVariable(isVariable: boolean) {
             const signature = this.getActiveSignatureHelpItem();
             assert.isOk(signature);
             assert.equal(isVariable, signature.isVariadic);
@@ -1053,6 +1053,10 @@ namespace FourSlash {
             assert.equal(this.getActiveSignatureHelpItem().parameters.length, expectedCount);
         }
 
+        public verifyCurrentSignatureHelpIsVariadic(expected: boolean) {
+            assert.equal(this.getActiveSignatureHelpItem().isVariadic, expected);
+        }
+
         public verifyCurrentSignatureHelpDocComment(docComment: string) {
             const actualDocComment = this.getActiveSignatureHelpItem().documentation;
             assert.equal(ts.displayPartsToString(actualDocComment), docComment, this.assertionMessageAtLastKnownMarker("current signature help doc comment"));
@@ -3231,6 +3235,10 @@ namespace FourSlashInterface {
             this.state.verifySignatureHelpCount(expected);
         }
 
+        public signatureHelpCurrentArgumentListIsVariadic(expected: boolean) {
+            this.state.verifyCurrentSignatureHelpIsVariadic(expected);
+        }
+
         public signatureHelpArgumentCountIs(expected: number) {
             this.state.verifySignatureHelpArgumentCount(expected);
         }
diff --git a/src/services/signatureHelp.ts b/src/services/signatureHelp.ts
index 211e55b23ba5e..44c2ede9fbb52 100644
--- a/src/services/signatureHelp.ts
+++ b/src/services/signatureHelp.ts
@@ -557,7 +557,9 @@ namespace ts.SignatureHelp {
                 addRange(prefixDisplayParts, callTargetDisplayParts);
             }
 
+            let isVariadic: boolean;
             if (isTypeParameterList) {
+                isVariadic = false; // type parameter lists are not variadic
                 prefixDisplayParts.push(punctuationPart(SyntaxKind.LessThanToken));
                 const typeParameters = candidateSignature.typeParameters;
                 signatureHelpParameters = typeParameters && typeParameters.length > 0 ? map(typeParameters, createSignatureHelpParameterForTypeParameter) : emptyArray;
@@ -567,6 +569,7 @@ namespace ts.SignatureHelp {
                 addRange(suffixDisplayParts, parameterParts);
             }
             else {
+                isVariadic = candidateSignature.hasRestParameter;
                 const typeParameterParts = mapToDisplayParts(writer =>
                     typeChecker.getSymbolDisplayBuilder().buildDisplayForTypeParametersAndDelimiters(candidateSignature.typeParameters, writer, invocation));
                 addRange(prefixDisplayParts, typeParameterParts);
@@ -582,7 +585,7 @@ namespace ts.SignatureHelp {
             addRange(suffixDisplayParts, returnTypeParts);
 
             return {
-                isVariadic: candidateSignature.hasRestParameter,
+                isVariadic,
                 prefixDisplayParts,
                 suffixDisplayParts,
                 separatorDisplayParts: [punctuationPart(SyntaxKind.CommaToken), spacePart()],
diff --git a/tests/cases/fourslash/fourslash.ts b/tests/cases/fourslash/fourslash.ts
index 0a72d29529586..295b8e422b9ba 100644
--- a/tests/cases/fourslash/fourslash.ts
+++ b/tests/cases/fourslash/fourslash.ts
@@ -194,6 +194,7 @@ declare namespace FourSlashInterface {
         currentSignatureHelpDocCommentIs(docComment: string): void;
         signatureHelpCountIs(expected: number): void;
         signatureHelpArgumentCountIs(expected: number): void;
+        signatureHelpCurrentArgumentListIsVariadic(expected: boolean);
         currentSignatureParameterCountIs(expected: number): void;
         currentSignatureTypeParameterCountIs(expected: number): void;
         currentSignatureHelpIs(expected: string): void;
diff --git a/tests/cases/fourslash/signatureHelpTypeParametersNotVariadic.ts b/tests/cases/fourslash/signatureHelpTypeParametersNotVariadic.ts
new file mode 100644
index 0000000000000..30b0bac7e7117
--- /dev/null
+++ b/tests/cases/fourslash/signatureHelpTypeParametersNotVariadic.ts
@@ -0,0 +1,8 @@
+/// <reference path="fourslash.ts" />
+
+//// declare function f(a: any, ...b: any[]): any;
+//// f</*1*/>(1, 2);
+
+goTo.marker("1");
+verify.signatureHelpArgumentCountIs(0);
+verify.signatureHelpCurrentArgumentListIsVariadic(false);
\ No newline at end of file

From 64563259733f5c611860a9ca88f99d8859a7b24e Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Tue, 8 Nov 2016 16:28:10 -0800
Subject: [PATCH 203/224] Handle abstract and const modifiers

---
 src/compiler/program.ts                           | 15 ++++++++++-----
 .../jsFileCompilationAbstractModifier.errors.txt  | 14 ++++++++++++++
 .../jsFileCompilationConstModifier.symbols        |  4 ++++
 .../jsFileCompilationConstModifier.types          |  5 +++++
 .../compiler/jsFileCompilationAbstractModifier.ts |  5 +++++
 .../compiler/jsFileCompilationConstModifier.ts    |  4 ++++
 6 files changed, 42 insertions(+), 5 deletions(-)
 create mode 100644 tests/baselines/reference/jsFileCompilationAbstractModifier.errors.txt
 create mode 100644 tests/baselines/reference/jsFileCompilationConstModifier.symbols
 create mode 100644 tests/baselines/reference/jsFileCompilationConstModifier.types
 create mode 100644 tests/cases/compiler/jsFileCompilationAbstractModifier.ts
 create mode 100644 tests/cases/compiler/jsFileCompilationConstModifier.ts

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 06476d29fbeda..0257ed6387b9c 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -870,11 +870,12 @@ namespace ts {
                                 diagnostics.push(createDiagnosticForNodeArray(nodes, Diagnostics.type_parameter_declarations_can_only_be_used_in_a_ts_file));
                                 return;
                             }
-                        // pass through
+                            // pass through
+                            let isConstInvalid = true;
                         case SyntaxKind.VariableStatement:
                             // Check modifiers
                             if (nodes === (<ClassDeclaration | FunctionLikeDeclaration | VariableStatement>parent).modifiers) {
-                                return checkModifiers(<NodeArray<Modifier>>nodes);
+                                return checkModifiers(<NodeArray<Modifier>>nodes, !isConstInvalid);
                             }
                             break;
                         case SyntaxKind.PropertyDeclaration:
@@ -911,23 +912,27 @@ namespace ts {
                     }
                 }
 
-                function checkModifiers(modifiers: NodeArray<Modifier>) {
+                function checkModifiers(modifiers: NodeArray<Modifier>, isConstValid: boolean) {
                     for (const modifier of modifiers) {
                         switch (modifier.kind) {
+                            case SyntaxKind.ConstKeyword:
+                                if (isConstValid) {
+                                    continue;
+                                }
+                                // Fallthrough to report error
                             case SyntaxKind.PublicKeyword:
                             case SyntaxKind.PrivateKeyword:
                             case SyntaxKind.ProtectedKeyword:
                             case SyntaxKind.ReadonlyKeyword:
                             case SyntaxKind.DeclareKeyword:
+                            case SyntaxKind.AbstractKeyword:
                                 diagnostics.push(createDiagnosticForNode(modifier, Diagnostics._0_can_only_be_used_in_a_ts_file, tokenToString(modifier.kind)));
                                 break;
 
                             // These are all legal modifiers.
                             case SyntaxKind.StaticKeyword:
                             case SyntaxKind.ExportKeyword:
-                            case SyntaxKind.ConstKeyword:
                             case SyntaxKind.DefaultKeyword:
-                            case SyntaxKind.AbstractKeyword:
                         }
                     }
                 }
diff --git a/tests/baselines/reference/jsFileCompilationAbstractModifier.errors.txt b/tests/baselines/reference/jsFileCompilationAbstractModifier.errors.txt
new file mode 100644
index 0000000000000..62fc2c3e8542a
--- /dev/null
+++ b/tests/baselines/reference/jsFileCompilationAbstractModifier.errors.txt
@@ -0,0 +1,14 @@
+error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+tests/cases/compiler/a.js(1,1): error TS8009: 'abstract' can only be used in a .ts file.
+tests/cases/compiler/a.js(2,5): error TS8009: 'abstract' can only be used in a .ts file.
+
+
+!!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+==== tests/cases/compiler/a.js (2 errors) ====
+    abstract class c {
+    ~~~~~~~~
+!!! error TS8009: 'abstract' can only be used in a .ts file.
+        abstract x;
+        ~~~~~~~~
+!!! error TS8009: 'abstract' can only be used in a .ts file.
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/jsFileCompilationConstModifier.symbols b/tests/baselines/reference/jsFileCompilationConstModifier.symbols
new file mode 100644
index 0000000000000..137dafd3473ae
--- /dev/null
+++ b/tests/baselines/reference/jsFileCompilationConstModifier.symbols
@@ -0,0 +1,4 @@
+=== tests/cases/compiler/a.js ===
+const c = 10;
+>c : Symbol(c, Decl(a.js, 0, 5))
+
diff --git a/tests/baselines/reference/jsFileCompilationConstModifier.types b/tests/baselines/reference/jsFileCompilationConstModifier.types
new file mode 100644
index 0000000000000..8e74679f2a599
--- /dev/null
+++ b/tests/baselines/reference/jsFileCompilationConstModifier.types
@@ -0,0 +1,5 @@
+=== tests/cases/compiler/a.js ===
+const c = 10;
+>c : 10
+>10 : 10
+
diff --git a/tests/cases/compiler/jsFileCompilationAbstractModifier.ts b/tests/cases/compiler/jsFileCompilationAbstractModifier.ts
new file mode 100644
index 0000000000000..ebd021e05a154
--- /dev/null
+++ b/tests/cases/compiler/jsFileCompilationAbstractModifier.ts
@@ -0,0 +1,5 @@
+// @allowJs: true
+// @filename: a.js
+abstract class c {
+    abstract x;
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/jsFileCompilationConstModifier.ts b/tests/cases/compiler/jsFileCompilationConstModifier.ts
new file mode 100644
index 0000000000000..4ffa62bb6a24b
--- /dev/null
+++ b/tests/cases/compiler/jsFileCompilationConstModifier.ts
@@ -0,0 +1,4 @@
+// @allowJs: true
+// @filename: a.js
+// @noEmit: true
+const c = 10;
\ No newline at end of file

From 214ce38a6a64441232b5e7e72d78a2687edfe743 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 9 Nov 2016 10:47:54 -0800
Subject: [PATCH 204/224] Downlevel array destructuring to ES6 in object rest

Previously array destructuring inside an object destructuring with an
object rest would downlevel the array destructuring to ES5. This breaks
if the code that targets ES2015 is using iterators instead of arrays
since iterators don't support [0] or .slice that the ES5 emit uses.
---
 src/compiler/factory.ts                    |   3 +-
 src/compiler/transformers/destructuring.ts | 141 ++++++++++++++++-----
 2 files changed, 110 insertions(+), 34 deletions(-)

diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 790f9c2df6fb8..40f5910009ca8 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -3568,8 +3568,7 @@ namespace ts {
         setEmitFlags(body, EmitFlags.NoSourceMap | EmitFlags.NoTokenSourceMaps);
 
         let forStatement: ForStatement | ForOfStatement;
-        if(convertObjectRest) {
-
+        if (convertObjectRest) {
             forStatement = createForOf(
                 createVariableDeclarationList([
                     createVariableDeclaration(rhsReference, /*type*/ undefined, /*initializer*/ undefined, /*location*/ node.expression)
diff --git a/src/compiler/transformers/destructuring.ts b/src/compiler/transformers/destructuring.ts
index 66b907d4d9030..bba09710898f0 100644
--- a/src/compiler/transformers/destructuring.ts
+++ b/src/compiler/transformers/destructuring.ts
@@ -52,7 +52,7 @@ namespace ts {
             location = value;
         }
 
-        flattenDestructuring(node, value, location, emitAssignment, emitTempVariableAssignment, emitRestAssignment, transformRest, visitor);
+        flattenDestructuring(node, value, location, emitAssignment, emitTempVariableAssignment, recordTempVariable, emitRestAssignment, transformRest, visitor);
 
         if (needsValue) {
             expressions.push(value);
@@ -98,7 +98,7 @@ namespace ts {
         transformRest?: boolean) {
         const declarations: VariableDeclaration[] = [];
 
-        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, emitRestAssignment, transformRest, visitor);
+        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, noop, emitRestAssignment, transformRest, visitor);
 
         return declarations;
 
@@ -140,7 +140,7 @@ namespace ts {
         const declarations: VariableDeclaration[] = [];
 
         let pendingAssignments: Expression[];
-        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, emitRestAssignment, transformRest, visitor);
+        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, recordTempVariable, emitRestAssignment, transformRest, visitor);
 
         return declarations;
 
@@ -201,7 +201,7 @@ namespace ts {
 
         const pendingAssignments: Expression[] = [];
 
-        flattenDestructuring(node, /*value*/ undefined, node, emitAssignment, emitTempVariableAssignment, emitRestAssignment, /*transformRest*/ false, visitor);
+        flattenDestructuring(node, /*value*/ undefined, node, emitAssignment, emitTempVariableAssignment, noop, emitRestAssignment, /*transformRest*/ false, visitor);
 
         const expression = inlineExpressions(pendingAssignments);
         aggregateTransformFlags(expression);
@@ -244,6 +244,7 @@ namespace ts {
         location: TextRange,
         emitAssignment: (name: Identifier, value: Expression, location: TextRange, original: Node) => void,
         emitTempVariableAssignment: (value: Expression, location: TextRange) => Identifier,
+        recordTempVariable: (node: Identifier) => void,
         emitRestAssignment: (elements: (ObjectLiteralElementLike[] | BindingElement[]), value: Expression, location: TextRange, original: Node) => void,
         transformRest: boolean,
         visitor?: (node: Node) => VisitResult<Node>) {
@@ -307,48 +308,91 @@ namespace ts {
                 value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ true, location, emitTempVariableAssignment);
             }
 
-            let es2015: ObjectLiteralElementLike[] = [];
+            let bindingElements: ObjectLiteralElementLike[] = [];
             for (let i = 0; i < properties.length; i++) {
                 const p = properties[i];
                 if (p.kind === SyntaxKind.PropertyAssignment || p.kind === SyntaxKind.ShorthandPropertyAssignment) {
-                    if (transformRest && !(p.transformFlags & TransformFlags.ContainsSpreadExpression)) {
-                        es2015.push(p);
-                    }
-                    else {
-                        if (es2015.length) {
-                            emitRestAssignment(es2015, value, location, target);
-                            es2015 = [];
+                    if (!transformRest ||
+                        p.transformFlags & TransformFlags.ContainsSpreadExpression ||
+                        (p.kind === SyntaxKind.PropertyAssignment && p.initializer.transformFlags & TransformFlags.ContainsSpreadExpression)) {
+                        if (bindingElements.length) {
+                            emitRestAssignment(bindingElements, value, location, target);
+                            bindingElements = [];
                         }
                         const propName = <Identifier | LiteralExpression>(<PropertyAssignment>p).name;
                         const bindingTarget = p.kind === SyntaxKind.ShorthandPropertyAssignment ? <ShorthandPropertyAssignment>p : (<PropertyAssignment>p).initializer || propName;
                         // Assignment for bindingTarget = value.propName should highlight whole property, hence use p as source map node
                         emitDestructuringAssignment(bindingTarget, createDestructuringPropertyAccess(value, propName), p);
                     }
+                    else {
+                        bindingElements.push(p);
+                    }
                 }
                 else if (i === properties.length - 1 && p.kind === SyntaxKind.SpreadAssignment) {
                     Debug.assert((p as SpreadAssignment).expression.kind === SyntaxKind.Identifier);
-                    if (es2015.length) {
-                        emitRestAssignment(es2015, value, location, target);
-                        es2015 = [];
+                    if (bindingElements.length) {
+                        emitRestAssignment(bindingElements, value, location, target);
+                        bindingElements = [];
                     }
                     const propName = (p as SpreadAssignment).expression as Identifier;
                     const restCall = createRestCall(value, target.properties, p => p.name, target);
                     emitDestructuringAssignment(propName, restCall, p);
                 }
             }
-            if (es2015.length) {
-                emitRestAssignment(es2015, value, location, target);
-                es2015 = [];
+            if (bindingElements.length) {
+                emitRestAssignment(bindingElements, value, location, target);
+                bindingElements = [];
             }
         }
 
         function emitArrayLiteralAssignment(target: ArrayLiteralExpression, value: Expression, location: TextRange) {
+            if (transformRest) {
+                emitESNextArrayLiteralAssignment(target, value, location);
+            }
+            else {
+                emitES2015ArrayLiteralAssignment(target, value, location);
+            }
+        }
+
+        function emitESNextArrayLiteralAssignment(target: ArrayLiteralExpression, value: Expression, location: TextRange) {
             const elements = target.elements;
             const numElements = elements.length;
             if (numElements !== 1) {
                 // For anything but a single element destructuring we need to generate a temporary
                 // to ensure value is evaluated exactly once.
-                // When doing so we want to hightlight the passed in source map node since thats the one needing this temp assignment
+                // When doing so we want to highlight the passed-in source map node since thats the one needing this temp assignment
+                value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ true, location, emitTempVariableAssignment);
+            }
+
+            const expressions: Expression[] = [];
+            const spreadContainingExpressions: [Expression, Identifier][] = [];
+            for (let i = 0; i < numElements; i++) {
+                const e = elements[i];
+                if (e.kind === SyntaxKind.OmittedExpression) {
+                    continue;
+                }
+                if (e.transformFlags & TransformFlags.ContainsSpreadExpression && i < numElements - 1) {
+                    const tmp = createTempVariable(recordTempVariable);
+                    spreadContainingExpressions.push([e, tmp]);
+                    expressions.push(tmp);
+                }
+                else {
+                    expressions.push(e);
+                }
+            }
+            emitAssignment(updateArrayLiteral(target, expressions) as any as Identifier, value, undefined, undefined);
+            for (const [e, tmp] of spreadContainingExpressions) {
+                emitDestructuringAssignment(e, tmp, e);
+            }
+        }
+
+        function emitES2015ArrayLiteralAssignment(target: ArrayLiteralExpression, value: Expression, location: TextRange) {
+            const elements = target.elements;
+            const numElements = elements.length;
+            if (numElements !== 1) {
+                // For anything but a single element destructuring we need to generate a temporary
+                // to ensure value is evaluated exactly once.
+                // When doing so we want to highlight the passed-in source map node since thats the one needing this temp assignment
                 value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ true, location, emitTempVariableAssignment);
             }
 
@@ -413,7 +457,7 @@ namespace ts {
                     value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ numElements !== 0, target, emitTempVariableAssignment);
                 }
                 if (name.kind === SyntaxKind.ArrayBindingPattern) {
-                    emitArrayBindingElement(name, value);
+                    emitArrayBindingElement(name as ArrayBindingPattern, value);
                 }
                 else {
                     emitObjectBindingElement(target, value);
@@ -421,7 +465,16 @@ namespace ts {
             }
         }
 
-        function emitArrayBindingElement(name: BindingPattern, value: Expression) {
+        function emitArrayBindingElement(name: ArrayBindingPattern, value: Expression) {
+            if (transformRest) {
+                emitESNextArrayBindingElement(name, value);
+            }
+            else {
+                emitES2015ArrayBindingElement(name, value);
+            }
+        }
+
+        function emitES2015ArrayBindingElement(name: ArrayBindingPattern, value: Expression) {
             const elements = name.elements;
             const numElements = elements.length;
             for (let i = 0; i < numElements; i++) {
@@ -439,20 +492,44 @@ namespace ts {
             }
         }
 
+        function emitESNextArrayBindingElement(name: ArrayBindingPattern, value: Expression) {
+            const elements = name.elements;
+            const numElements = elements.length;
+            const bindingElements: BindingElement[] = [];
+            const spreadContainingElements: BindingElement[] = [];
+            for (let i = 0; i < numElements; i++) {
+                const element = elements[i];
+                if (isOmittedExpression(element)) {
+                    continue;
+                }
+                if (element.transformFlags & TransformFlags.ContainsSpreadExpression && i < numElements - 1) {
+                    spreadContainingElements.push(element);
+                    bindingElements.push(createBindingElement(undefined, undefined, getGeneratedNameForNode(element), undefined, value));
+                }
+                else {
+                    bindingElements.push(element);
+                }
+            }
+            emitAssignment(updateArrayBindingPattern(name, bindingElements) as any as Identifier, value, undefined, undefined);
+            for (const element of spreadContainingElements) {
+                emitBindingElement(element, getGeneratedNameForNode(element));
+            }
+        }
+
         function emitObjectBindingElement(target: VariableDeclaration | ParameterDeclaration | BindingElement, value: Expression) {
             const name = target.name as BindingPattern;
             const elements = name.elements;
             const numElements = elements.length;
-            let es2015: BindingElement[] = [];
+            let bindingElements: BindingElement[] = [];
             for (let i = 0; i < numElements; i++) {
                 const element = elements[i];
                 if (isOmittedExpression(element)) {
                     continue;
                 }
                 if (i === numElements - 1 && element.dotDotDotToken) {
-                    if (es2015.length) {
-                        emitRestAssignment(es2015, value, target, target);
-                        es2015 = [];
+                    if (bindingElements.length) {
+                        emitRestAssignment(bindingElements, value, target, target);
+                        bindingElements = [];
                     }
                     const restCall = createRestCall(value,
                                                     name.elements,
@@ -462,21 +539,21 @@ namespace ts {
                 }
                 else if (transformRest && !(element.transformFlags & TransformFlags.ContainsSpreadExpression)) {
                     // do not emit until we have a complete bundle of ES2015 syntax
-                    es2015.push(element);
+                    bindingElements.push(element);
                 }
                 else {
-                    if (es2015.length) {
-                        emitRestAssignment(es2015, value, target, target);
-                        es2015 = [];
+                    if (bindingElements.length) {
+                        emitRestAssignment(bindingElements, value, target, target);
+                        bindingElements = [];
                     }
                     // Rewrite element to a declaration with an initializer that fetches property
                     const propName = element.propertyName || <Identifier>element.name;
                     emitBindingElement(element, createDestructuringPropertyAccess(value, propName));
                 }
             }
-            if (es2015.length) {
-                emitRestAssignment(es2015, value, target, target);
-                es2015 = [];
+            if (bindingElements.length) {
+                emitRestAssignment(bindingElements, value, target, target);
+                bindingElements = [];
             }
         }
 

From 01969475cf576b4f476beeb5aca648e743eb5cd2 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 9 Nov 2016 10:51:56 -0800
Subject: [PATCH 205/224] Improve nested destructuring test for ESNext emit

Now with object destructuring inside array destructuring inside object
destructuring! Each with their own array/object rest!

Also updates baselines.
---
 .../reference/objectRestAssignment.js         | 26 ++++++++----
 .../reference/objectRestAssignment.symbols    | 31 ++++++++++++++
 .../reference/objectRestAssignment.types      | 41 +++++++++++++++++++
 .../types/rest/objectRestAssignment.ts        |  8 ++++
 4 files changed, 99 insertions(+), 7 deletions(-)

diff --git a/tests/baselines/reference/objectRestAssignment.js b/tests/baselines/reference/objectRestAssignment.js
index 20f87ff837564..41620d59b584f 100644
--- a/tests/baselines/reference/objectRestAssignment.js
+++ b/tests/baselines/reference/objectRestAssignment.js
@@ -5,6 +5,13 @@ let other: number;
 let rest: { };
 let complex: { x: { ka, ki }, y: number };
 ({x: { ka, ...nested }, y: other, ...rest} = complex);
+
+// should be:
+let overEmit: { a: { ka: string, x: string }[], b: { z: string, ki: string, ku: string }, ke: string, ko: string };
+
+// var _g = overEmit.a, [_h, ...y] = _g, nested2 = __rest(_h, []), _j = overEmit.b, { z } = _j, c = __rest(_j, ["z"]), rest2 = __rest(overEmit, ["a", "b"]);
+var { a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit;
+({ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit);
 
 
 //// [objectRestAssignment.js]
@@ -14,10 +21,15 @@ var __rest = (this && this.__rest) || function (s, e) {
         t[p] = s[p];
     return t;
 };
-var ka;
-var nested;
-var other;
-var rest;
-var complex;
-(_a = complex.x, (ka = _a.ka, _a), nested = __rest(_a, ["ka"]), (other = complex.y, complex), rest = __rest(complex, ["x", "y"]), complex);
-var _a;
+let ka;
+let nested;
+let other;
+let rest;
+let complex;
+(_a = complex.x, { ka } = _a, nested = __rest(_a, ["ka"]), { y: other } = complex, rest = __rest(complex, ["x", "y"]), complex);
+// should be:
+let overEmit;
+// var _g = overEmit.a, [_h, ...y] = _g, nested2 = __rest(_h, []), _j = overEmit.b, { z } = _j, c = __rest(_j, ["z"]), rest2 = __rest(overEmit, ["a", "b"]);
+var _b = overEmit.a, [_c, ...y] = _b, nested2 = __rest(_c, []), _d = overEmit.b, { z } = _d, c = __rest(_d, ["z"]), rest2 = __rest(overEmit, ["a", "b"]);
+(_e = overEmit.a, [_f, ...y] = _e, nested2 = __rest(_f, []), _g = overEmit.b, { z } = _g, c = __rest(_g, ["z"]), rest2 = __rest(overEmit, ["a", "b"]), overEmit);
+var _a, _e, _f, _g;
diff --git a/tests/baselines/reference/objectRestAssignment.symbols b/tests/baselines/reference/objectRestAssignment.symbols
index 38127dbee2d2c..4cb27e6e7ecd6 100644
--- a/tests/baselines/reference/objectRestAssignment.symbols
+++ b/tests/baselines/reference/objectRestAssignment.symbols
@@ -26,3 +26,34 @@ let complex: { x: { ka, ki }, y: number };
 >other : Symbol(other, Decl(objectRestAssignment.ts, 2, 3))
 >complex : Symbol(complex, Decl(objectRestAssignment.ts, 4, 3))
 
+// should be:
+let overEmit: { a: { ka: string, x: string }[], b: { z: string, ki: string, ku: string }, ke: string, ko: string };
+>overEmit : Symbol(overEmit, Decl(objectRestAssignment.ts, 8, 3))
+>a : Symbol(a, Decl(objectRestAssignment.ts, 8, 15))
+>ka : Symbol(ka, Decl(objectRestAssignment.ts, 8, 20))
+>x : Symbol(x, Decl(objectRestAssignment.ts, 8, 32))
+>b : Symbol(b, Decl(objectRestAssignment.ts, 8, 47))
+>z : Symbol(z, Decl(objectRestAssignment.ts, 8, 52))
+>ki : Symbol(ki, Decl(objectRestAssignment.ts, 8, 63))
+>ku : Symbol(ku, Decl(objectRestAssignment.ts, 8, 75))
+>ke : Symbol(ke, Decl(objectRestAssignment.ts, 8, 89))
+>ko : Symbol(ko, Decl(objectRestAssignment.ts, 8, 101))
+
+// var _g = overEmit.a, [_h, ...y] = _g, nested2 = __rest(_h, []), _j = overEmit.b, { z } = _j, c = __rest(_j, ["z"]), rest2 = __rest(overEmit, ["a", "b"]);
+var { a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit;
+>a : Symbol(a, Decl(objectRestAssignment.ts, 8, 15))
+>nested2 : Symbol(nested2, Decl(objectRestAssignment.ts, 11, 11))
+>y : Symbol(y, Decl(objectRestAssignment.ts, 11, 25))
+>b : Symbol(b, Decl(objectRestAssignment.ts, 8, 47))
+>z : Symbol(z, Decl(objectRestAssignment.ts, 11, 37))
+>c : Symbol(c, Decl(objectRestAssignment.ts, 11, 40))
+>rest2 : Symbol(rest2, Decl(objectRestAssignment.ts, 11, 48))
+>overEmit : Symbol(overEmit, Decl(objectRestAssignment.ts, 8, 3))
+
+({ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit);
+>a : Symbol(a, Decl(objectRestAssignment.ts, 12, 2))
+>y : Symbol(y, Decl(objectRestAssignment.ts, 11, 25))
+>b : Symbol(b, Decl(objectRestAssignment.ts, 12, 29))
+>z : Symbol(z, Decl(objectRestAssignment.ts, 12, 34))
+>overEmit : Symbol(overEmit, Decl(objectRestAssignment.ts, 8, 3))
+
diff --git a/tests/baselines/reference/objectRestAssignment.types b/tests/baselines/reference/objectRestAssignment.types
index a4d88f89bb276..38aa00ce61dc4 100644
--- a/tests/baselines/reference/objectRestAssignment.types
+++ b/tests/baselines/reference/objectRestAssignment.types
@@ -32,3 +32,44 @@ let complex: { x: { ka, ki }, y: number };
 >rest : any
 >complex : { x: { ka: any; ki: any; }; y: number; }
 
+// should be:
+let overEmit: { a: { ka: string, x: string }[], b: { z: string, ki: string, ku: string }, ke: string, ko: string };
+>overEmit : { a: { ka: string; x: string; }[]; b: { z: string; ki: string; ku: string; }; ke: string; ko: string; }
+>a : { ka: string; x: string; }[]
+>ka : string
+>x : string
+>b : { z: string; ki: string; ku: string; }
+>z : string
+>ki : string
+>ku : string
+>ke : string
+>ko : string
+
+// var _g = overEmit.a, [_h, ...y] = _g, nested2 = __rest(_h, []), _j = overEmit.b, { z } = _j, c = __rest(_j, ["z"]), rest2 = __rest(overEmit, ["a", "b"]);
+var { a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit;
+>a : any
+>nested2 : { ka: string; x: string; }
+>y : { ka: string; x: string; }[]
+>b : any
+>z : string
+>c : { ki: string; ku: string; }
+>rest2 : { ke: string; ko: string; }
+>overEmit : { a: { ka: string; x: string; }[]; b: { z: string; ki: string; ku: string; }; ke: string; ko: string; }
+
+({ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit);
+>({ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit) : { a: { ka: string; x: string; }[]; b: { z: string; ki: string; ku: string; }; ke: string; ko: string; }
+>{ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit : { a: { ka: string; x: string; }[]; b: { z: string; ki: string; ku: string; }; ke: string; ko: string; }
+>{ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } : { ke: string; ko: string; a: { ka: string; x: string; }[]; b: { ki: string; ku: string; z: string; }; }
+>a : { ka: string; x: string; }[]
+>[{ ...nested2 }, ...y] : { ka: string; x: string; }[]
+>{ ...nested2 } : { ka: string; x: string; }
+>nested2 : any
+>...y : { ka: string; x: string; }
+>y : { ka: string; x: string; }[]
+>b : { ki: string; ku: string; z: string; }
+>{ z, ...c } : { ki: string; ku: string; z: string; }
+>z : string
+>c : any
+>rest2 : any
+>overEmit : { a: { ka: string; x: string; }[]; b: { z: string; ki: string; ku: string; }; ke: string; ko: string; }
+
diff --git a/tests/cases/conformance/types/rest/objectRestAssignment.ts b/tests/cases/conformance/types/rest/objectRestAssignment.ts
index 4c8da304bc3c3..dedc99b1f713a 100644
--- a/tests/cases/conformance/types/rest/objectRestAssignment.ts
+++ b/tests/cases/conformance/types/rest/objectRestAssignment.ts
@@ -1,6 +1,14 @@
+// @target: es2015
 let ka: any;
 let nested: { ki };
 let other: number;
 let rest: { };
 let complex: { x: { ka, ki }, y: number };
 ({x: { ka, ...nested }, y: other, ...rest} = complex);
+
+// should be:
+let overEmit: { a: { ka: string, x: string }[], b: { z: string, ki: string, ku: string }, ke: string, ko: string };
+
+// var _g = overEmit.a, [_h, ...y] = _g, nested2 = __rest(_h, []), _j = overEmit.b, { z } = _j, c = __rest(_j, ["z"]), rest2 = __rest(overEmit, ["a", "b"]);
+var { a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit;
+({ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit);

From 4b8a55793a5378bcde27e08212da2a107f773286 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Wed, 9 Nov 2016 12:12:48 -0800
Subject: [PATCH 206/224] Add support for taking in jsxFactory option and
 report errors for invalid combinations

---
 src/compiler/commandLineParser.ts             |  5 ++
 src/compiler/diagnosticMessages.json          |  4 +
 src/compiler/program.ts                       |  7 +-
 src/compiler/types.ts                         |  1 +
 .../jsxFactoryAndReactNamespace.errors.txt    | 53 ++++++++++++
 .../reference/jsxFactoryAndReactNamespace.js  | 81 +++++++++++++++++++
 .../compiler/jsxFactoryAndReactNamespace.ts   | 54 +++++++++++++
 7 files changed, 204 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/jsxFactoryAndReactNamespace.errors.txt
 create mode 100644 tests/baselines/reference/jsxFactoryAndReactNamespace.js
 create mode 100644 tests/cases/compiler/jsxFactoryAndReactNamespace.ts

diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 50399fd5c38e7..1dfecf33b89a9 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -77,6 +77,11 @@ namespace ts {
             type: "string",
             description: Diagnostics.Specify_the_object_invoked_for_createElement_and_spread_when_targeting_react_JSX_emit
         },
+        {
+            name: "jsxFactory",
+            type: "string",
+            description: Diagnostics.Specify_the_JSX_factory_function_to_use_when_targeting_react_JSX_emit_e_g_React_createElement_or_h
+        },
         {
             name: "listFiles",
             type: "boolean",
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 9a353e6fb3651..79e3178839014 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -2897,6 +2897,10 @@
         "category": "Message",
         "code": 6145
     },
+    "Specify the JSX factory function to use when targeting 'react' JSX emit, e.g. 'React.createElement' or 'h'.": {
+        "category": "Message",
+        "code": 6146
+    },
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 1b36d99d7c9d7..cb7efc49bf3aa 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1670,7 +1670,12 @@ namespace ts {
                 programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Option_0_cannot_be_specified_without_specifying_option_1, "emitDecoratorMetadata", "experimentalDecorators"));
             }
 
-            if (options.reactNamespace && !isIdentifierText(options.reactNamespace, languageVersion)) {
+            if (options.jsxFactory) {
+                if (options.reactNamespace) {
+                    programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Option_0_cannot_be_specified_with_option_1, "reactNamespace", "jsxFactory"));
+                }
+            }
+            else if (options.reactNamespace && !isIdentifierText(options.reactNamespace, languageVersion)) {
                 programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Invalid_value_for_reactNamespace_0_is_not_a_valid_identifier, options.reactNamespace));
             }
 
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index fb1dffad87db8..5ca542cfe1118 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -3081,6 +3081,7 @@ namespace ts {
         project?: string;
         /* @internal */ pretty?: DiagnosticStyle;
         reactNamespace?: string;
+        jsxFactory?: string;
         removeComments?: boolean;
         rootDir?: string;
         rootDirs?: string[];
diff --git a/tests/baselines/reference/jsxFactoryAndReactNamespace.errors.txt b/tests/baselines/reference/jsxFactoryAndReactNamespace.errors.txt
new file mode 100644
index 0000000000000..c4859fd534cad
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryAndReactNamespace.errors.txt
@@ -0,0 +1,53 @@
+error TS5053: Option 'reactNamespace' cannot be specified with option 'jsxFactory'.
+
+
+!!! error TS5053: Option 'reactNamespace' cannot be specified with option 'jsxFactory'.
+==== tests/cases/compiler/Element.ts (0 errors) ====
+    
+    declare namespace JSX {
+        interface Element {
+            name: string;
+            isIntrinsic: boolean;
+            isCustomElement: boolean;
+            toString(renderId?: number): string;
+            bindDOM(renderId?: number): number;
+            resetComponent(): void;
+            instantiateComponents(renderId?: number): number;
+            props: any;
+        }
+    }
+    export namespace Element {
+        export function isElement(el: any): el is JSX.Element {
+            return el.markAsChildOfRootElement !== undefined;
+        }
+    
+        export function createElement(args: any[]) {
+    
+            return {
+            }
+        }
+    }
+    
+    export let createElement = Element.createElement;
+    
+    function toCamelCase(text: string): string {
+        return text[0].toLowerCase() + text.substring(1);
+    }
+    
+==== tests/cases/compiler/test.tsx (0 errors) ====
+    import { Element} from './Element';
+    
+    let c: {
+    	a?: {
+    		b: string
+    	}
+    };
+    
+    class A {
+    	view() {
+    		return [
+    			<meta content="helloworld"></meta>,
+    			<meta content={c.a!.b}></meta>
+    		];
+    	}
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryAndReactNamespace.js b/tests/baselines/reference/jsxFactoryAndReactNamespace.js
new file mode 100644
index 0000000000000..0a6402ca70cb2
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryAndReactNamespace.js
@@ -0,0 +1,81 @@
+//// [tests/cases/compiler/jsxFactoryAndReactNamespace.ts] ////
+
+//// [Element.ts]
+
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+//// [test.tsx]
+import { Element} from './Element';
+
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
+
+//// [Element.js]
+"use strict";
+var Element;
+(function (Element) {
+    function isElement(el) {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+    Element.isElement = isElement;
+    function createElement(args) {
+        return {};
+    }
+    Element.createElement = createElement;
+})(Element = exports.Element || (exports.Element = {}));
+exports.createElement = Element.createElement;
+function toCamelCase(text) {
+    return text[0].toLowerCase() + text.substring(1);
+}
+//// [test.js]
+"use strict";
+const Element_1 = require("./Element");
+let c;
+class A {
+    view() {
+        return [
+            Element_1.Element.createElement("meta", { content: "helloworld" }),
+            Element_1.Element.createElement("meta", { content: c.a.b })
+        ];
+    }
+}
diff --git a/tests/cases/compiler/jsxFactoryAndReactNamespace.ts b/tests/cases/compiler/jsxFactoryAndReactNamespace.ts
new file mode 100644
index 0000000000000..2bdc954da3af8
--- /dev/null
+++ b/tests/cases/compiler/jsxFactoryAndReactNamespace.ts
@@ -0,0 +1,54 @@
+//@jsx: react
+//@target: es6
+//@module: commonjs
+//@reactNamespace: Element
+//@jsxFactory: Element.createElement
+
+// @filename: Element.ts
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+// @filename: test.tsx
+import { Element} from './Element';
+
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
\ No newline at end of file

From fcf32c444f8d4eb8382d9ff7b3fb3c278b8ec1b8 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 9 Nov 2016 13:39:42 -0800
Subject: [PATCH 207/224] Treat `| undefined` like optionality in spread type

---
 src/compiler/checker.ts | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 8ac6b0f647190..8558871e6bf40 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4523,7 +4523,7 @@ namespace ts {
                 t;
         }
 
-        function createUnionOrIntersectionProperty(containingType: UnionOrIntersectionType, name: string) {
+        function createUnionOrIntersectionProperty(containingType: UnionOrIntersectionType, name: string): Symbol {
             const types = containingType.types;
             let props: Symbol[];
             // Flags we want to propagate to the result if they exist in all source symbols
@@ -5914,11 +5914,12 @@ namespace ts {
                 }
                 if (leftProp.name in members) {
                     const rightProp = members[leftProp.name];
-                    if (rightProp.flags & SymbolFlags.Optional) {
+                    const rightType = getTypeOfSymbol(rightProp);
+                    if (maybeTypeOfKind(rightType, TypeFlags.Undefined) || rightProp.flags & SymbolFlags.Optional) {
                         const declarations: Declaration[] = concatenate(leftProp.declarations, rightProp.declarations);
                         const flags = SymbolFlags.Property | SymbolFlags.Transient | (leftProp.flags & SymbolFlags.Optional);
                         const result = <TransientSymbol>createSymbol(flags, leftProp.name);
-                        result.type = getUnionType([getTypeOfSymbol(leftProp), getTypeOfSymbol(rightProp)]);
+                        result.type = getUnionType([getTypeOfSymbol(leftProp), getTypeWithFacts(rightType, TypeFacts.NEUndefined)]);
                         result.leftSpread = leftProp;
                         result.rightSpread = rightProp;
                         result.declarations = declarations;

From 9b1f43bdda5118046ce7b604ca978a83fc4e10f5 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 9 Nov 2016 13:40:21 -0800
Subject: [PATCH 208/224] Add strictNullChecks test for object spread

---
 .../reference/objectSpreadStrictNull.js       | 43 +++++++++
 .../reference/objectSpreadStrictNull.symbols  | 60 +++++++++++++
 .../reference/objectSpreadStrictNull.types    | 88 +++++++++++++++++++
 .../types/spread/objectSpreadStrictNull.ts    | 21 +++++
 4 files changed, 212 insertions(+)
 create mode 100644 tests/baselines/reference/objectSpreadStrictNull.js
 create mode 100644 tests/baselines/reference/objectSpreadStrictNull.symbols
 create mode 100644 tests/baselines/reference/objectSpreadStrictNull.types
 create mode 100644 tests/cases/conformance/types/spread/objectSpreadStrictNull.ts

diff --git a/tests/baselines/reference/objectSpreadStrictNull.js b/tests/baselines/reference/objectSpreadStrictNull.js
new file mode 100644
index 0000000000000..84604d728cdfc
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadStrictNull.js
@@ -0,0 +1,43 @@
+//// [objectSpreadStrictNull.ts]
+
+function f(
+    definiteBoolean: { sn: boolean },
+    definiteString: { sn: string },
+    optionalString: { sn?: string },
+    optionalNumber: { sn?: number },
+    undefinedString: { sn: string | undefined },
+    undefinedNumber: { sn: number | undefined }) {
+    // optional
+    let optionalUnionStops: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
+    let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
+    let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
+
+    // undefined
+    let undefinedUnionStops: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...undefinedNumber };
+    let undefinedUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...undefinedString, ...undefinedNumber };
+    let allUndefined: { sn: string | number | undefined } = { ...undefinedString, ...undefinedNumber };
+
+    let undefinedWithOptionalContinues: { sn: string | number | boolean } = { ...definiteBoolean, ...undefinedString, ...optionalNumber };
+}
+
+
+//// [objectSpreadStrictNull.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+function f(definiteBoolean, definiteString, optionalString, optionalNumber, undefinedString, undefinedNumber) {
+    // optional
+    var optionalUnionStops = __assign({}, definiteBoolean, definiteString, optionalNumber);
+    var optionalUnionDuplicates = __assign({}, definiteBoolean, definiteString, optionalString, optionalNumber);
+    var allOptional = __assign({}, optionalString, optionalNumber);
+    // undefined
+    var undefinedUnionStops = __assign({}, definiteBoolean, definiteString, undefinedNumber);
+    var undefinedUnionDuplicates = __assign({}, definiteBoolean, definiteString, undefinedString, undefinedNumber);
+    var allUndefined = __assign({}, undefinedString, undefinedNumber);
+    var undefinedWithOptionalContinues = __assign({}, definiteBoolean, undefinedString, optionalNumber);
+}
diff --git a/tests/baselines/reference/objectSpreadStrictNull.symbols b/tests/baselines/reference/objectSpreadStrictNull.symbols
new file mode 100644
index 0000000000000..85def473ce492
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadStrictNull.symbols
@@ -0,0 +1,60 @@
+=== tests/cases/conformance/types/spread/objectSpreadStrictNull.ts ===
+
+function f(
+>f : Symbol(f, Decl(objectSpreadStrictNull.ts, 0, 0))
+
+    definiteBoolean: { sn: boolean },
+>definiteBoolean : Symbol(definiteBoolean, Decl(objectSpreadStrictNull.ts, 1, 11))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 2, 22))
+
+    definiteString: { sn: string },
+>definiteString : Symbol(definiteString, Decl(objectSpreadStrictNull.ts, 2, 37))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 3, 21))
+
+    optionalString: { sn?: string },
+>optionalString : Symbol(optionalString, Decl(objectSpreadStrictNull.ts, 3, 35))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 4, 21))
+
+    optionalNumber: { sn?: number },
+>optionalNumber : Symbol(optionalNumber, Decl(objectSpreadStrictNull.ts, 4, 36))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 5, 21))
+
+    undefinedString: { sn: string | undefined },
+>undefinedString : Symbol(undefinedString, Decl(objectSpreadStrictNull.ts, 5, 36))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 6, 22))
+
+    undefinedNumber: { sn: number | undefined }) {
+>undefinedNumber : Symbol(undefinedNumber, Decl(objectSpreadStrictNull.ts, 6, 48))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 7, 22))
+
+    // optional
+    let optionalUnionStops: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
+>optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpreadStrictNull.ts, 9, 7))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 9, 29))
+
+    let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
+>optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpreadStrictNull.ts, 10, 7))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 10, 34))
+
+    let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
+>allOptional : Symbol(allOptional, Decl(objectSpreadStrictNull.ts, 11, 7))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 11, 22))
+
+    // undefined
+    let undefinedUnionStops: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...undefinedNumber };
+>undefinedUnionStops : Symbol(undefinedUnionStops, Decl(objectSpreadStrictNull.ts, 14, 7))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 14, 30))
+
+    let undefinedUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...undefinedString, ...undefinedNumber };
+>undefinedUnionDuplicates : Symbol(undefinedUnionDuplicates, Decl(objectSpreadStrictNull.ts, 15, 7))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 15, 35))
+
+    let allUndefined: { sn: string | number | undefined } = { ...undefinedString, ...undefinedNumber };
+>allUndefined : Symbol(allUndefined, Decl(objectSpreadStrictNull.ts, 16, 7))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 16, 23))
+
+    let undefinedWithOptionalContinues: { sn: string | number | boolean } = { ...definiteBoolean, ...undefinedString, ...optionalNumber };
+>undefinedWithOptionalContinues : Symbol(undefinedWithOptionalContinues, Decl(objectSpreadStrictNull.ts, 18, 7))
+>sn : Symbol(sn, Decl(objectSpreadStrictNull.ts, 18, 41))
+}
+
diff --git a/tests/baselines/reference/objectSpreadStrictNull.types b/tests/baselines/reference/objectSpreadStrictNull.types
new file mode 100644
index 0000000000000..a91295b2bca78
--- /dev/null
+++ b/tests/baselines/reference/objectSpreadStrictNull.types
@@ -0,0 +1,88 @@
+=== tests/cases/conformance/types/spread/objectSpreadStrictNull.ts ===
+
+function f(
+>f : (definiteBoolean: { sn: boolean; }, definiteString: { sn: string; }, optionalString: { sn?: string | undefined; }, optionalNumber: { sn?: number | undefined; }, undefinedString: { sn: string | undefined; }, undefinedNumber: { sn: number | undefined; }) => void
+
+    definiteBoolean: { sn: boolean },
+>definiteBoolean : { sn: boolean; }
+>sn : boolean
+
+    definiteString: { sn: string },
+>definiteString : { sn: string; }
+>sn : string
+
+    optionalString: { sn?: string },
+>optionalString : { sn?: string | undefined; }
+>sn : string | undefined
+
+    optionalNumber: { sn?: number },
+>optionalNumber : { sn?: number | undefined; }
+>sn : number | undefined
+
+    undefinedString: { sn: string | undefined },
+>undefinedString : { sn: string | undefined; }
+>sn : string | undefined
+
+    undefinedNumber: { sn: number | undefined }) {
+>undefinedNumber : { sn: number | undefined; }
+>sn : number | undefined
+
+    // optional
+    let optionalUnionStops: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
+>optionalUnionStops : { sn: string | number; }
+>sn : string | number
+>{ ...definiteBoolean, ...definiteString, ...optionalNumber } : { sn: string | number; }
+>definiteBoolean : any
+>definiteString : any
+>optionalNumber : any
+
+    let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
+>optionalUnionDuplicates : { sn: string | number; }
+>sn : string | number
+>{ ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber } : { sn: string | number; }
+>definiteBoolean : any
+>definiteString : any
+>optionalString : any
+>optionalNumber : any
+
+    let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
+>allOptional : { sn?: string | number | undefined; }
+>sn : string | number | undefined
+>{ ...optionalString, ...optionalNumber } : { sn?: string | number | undefined; }
+>optionalString : any
+>optionalNumber : any
+
+    // undefined
+    let undefinedUnionStops: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...undefinedNumber };
+>undefinedUnionStops : { sn: string | number; }
+>sn : string | number
+>{ ...definiteBoolean, ...definiteString, ...undefinedNumber } : { sn: string | number; }
+>definiteBoolean : any
+>definiteString : any
+>undefinedNumber : any
+
+    let undefinedUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...undefinedString, ...undefinedNumber };
+>undefinedUnionDuplicates : { sn: string | number; }
+>sn : string | number
+>{ ...definiteBoolean, ...definiteString, ...undefinedString, ...undefinedNumber } : { sn: string | number; }
+>definiteBoolean : any
+>definiteString : any
+>undefinedString : any
+>undefinedNumber : any
+
+    let allUndefined: { sn: string | number | undefined } = { ...undefinedString, ...undefinedNumber };
+>allUndefined : { sn: string | number | undefined; }
+>sn : string | number | undefined
+>{ ...undefinedString, ...undefinedNumber } : { sn: string | number | undefined; }
+>undefinedString : any
+>undefinedNumber : any
+
+    let undefinedWithOptionalContinues: { sn: string | number | boolean } = { ...definiteBoolean, ...undefinedString, ...optionalNumber };
+>undefinedWithOptionalContinues : { sn: string | number | boolean; }
+>sn : string | number | boolean
+>{ ...definiteBoolean, ...undefinedString, ...optionalNumber } : { sn: string | number | boolean; }
+>definiteBoolean : any
+>undefinedString : any
+>optionalNumber : any
+}
+
diff --git a/tests/cases/conformance/types/spread/objectSpreadStrictNull.ts b/tests/cases/conformance/types/spread/objectSpreadStrictNull.ts
new file mode 100644
index 0000000000000..087d47df26c35
--- /dev/null
+++ b/tests/cases/conformance/types/spread/objectSpreadStrictNull.ts
@@ -0,0 +1,21 @@
+// @strictNullChecks: true
+
+function f(
+    definiteBoolean: { sn: boolean },
+    definiteString: { sn: string },
+    optionalString: { sn?: string },
+    optionalNumber: { sn?: number },
+    undefinedString: { sn: string | undefined },
+    undefinedNumber: { sn: number | undefined }) {
+    // optional
+    let optionalUnionStops: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
+    let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
+    let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
+
+    // undefined
+    let undefinedUnionStops: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...undefinedNumber };
+    let undefinedUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...undefinedString, ...undefinedNumber };
+    let allUndefined: { sn: string | number | undefined } = { ...undefinedString, ...undefinedNumber };
+
+    let undefinedWithOptionalContinues: { sn: string | number | boolean } = { ...definiteBoolean, ...undefinedString, ...optionalNumber };
+}

From f7bac9894835fb55a75894c1ee82fe02e1e3a04c Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Wed, 9 Nov 2016 13:15:13 -0800
Subject: [PATCH 209/224] Verify that jsxFactory is either identifier or
 qualified name

---
 src/compiler/diagnosticMessages.json          |  4 +
 src/compiler/parser.ts                        | 14 ++++
 src/compiler/program.ts                       |  3 +
 src/harness/harness.ts                        | 10 +--
 .../reference/jsxFactoryIdentifier.errors.txt | 57 +++++++++++++
 .../reference/jsxFactoryIdentifier.js         | 82 +++++++++++++++++++
 ...oryNotIdentifierOrQualifiedName.errors.txt | 59 +++++++++++++
 .../jsxFactoryNotIdentifierOrQualifiedName.js | 80 ++++++++++++++++++
 ...ryNotIdentifierOrQualifiedName2.errors.txt | 59 +++++++++++++
 ...jsxFactoryNotIdentifierOrQualifiedName2.js | 80 ++++++++++++++++++
 .../jsxFactoryQualifiedName.errors.txt        | 57 +++++++++++++
 .../reference/jsxFactoryQualifiedName.js      | 80 ++++++++++++++++++
 tests/cases/compiler/jsxFactoryIdentifier.ts  | 53 ++++++++++++
 .../jsxFactoryNotIdentifierOrQualifiedName.ts | 53 ++++++++++++
 ...jsxFactoryNotIdentifierOrQualifiedName2.ts | 53 ++++++++++++
 .../cases/compiler/jsxFactoryQualifiedName.ts | 53 ++++++++++++
 16 files changed, 792 insertions(+), 5 deletions(-)
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifier.errors.txt
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifier.js
 create mode 100644 tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName.errors.txt
 create mode 100644 tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName.js
 create mode 100644 tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName2.errors.txt
 create mode 100644 tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName2.js
 create mode 100644 tests/baselines/reference/jsxFactoryQualifiedName.errors.txt
 create mode 100644 tests/baselines/reference/jsxFactoryQualifiedName.js
 create mode 100644 tests/cases/compiler/jsxFactoryIdentifier.ts
 create mode 100644 tests/cases/compiler/jsxFactoryNotIdentifierOrQualifiedName.ts
 create mode 100644 tests/cases/compiler/jsxFactoryNotIdentifierOrQualifiedName2.ts
 create mode 100644 tests/cases/compiler/jsxFactoryQualifiedName.ts

diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 79e3178839014..c7691b06da778 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -2381,6 +2381,10 @@
         "category": "Error",
         "code": 5066
     },
+    "Invalid value for 'jsxFactory'. '{0}' is not a valid identifier or qualified-name.": {
+        "category": "Error",
+        "code": 5067
+    },
     "Concatenate and emit output to single file.": {
         "category": "Message",
         "code": 6001
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 92a3dcbef11c7..0d15a54819293 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -438,6 +438,10 @@ namespace ts {
         return result;
     }
 
+    export function parseIsolatedEntityName(text: string, languageVersion: ScriptTarget): EntityName {
+        return Parser.parseIsolatedEntityName(text, languageVersion);
+    }
+
     export function isExternalModule(file: SourceFile): boolean {
         return file.externalModuleIndicator !== undefined;
     }
@@ -589,6 +593,16 @@ namespace ts {
             return result;
         }
 
+        export function parseIsolatedEntityName(content: string, languageVersion: ScriptTarget): EntityName {
+            initializeState(content, languageVersion, /*syntaxCursor*/ undefined, ScriptKind.JS);
+            // Prime the scanner.
+            nextToken();
+            const entityName = parseEntityName(/*allowReservedWords*/ true);
+            const isInvalid = token() === SyntaxKind.EndOfFileToken && !parseDiagnostics.length;
+            clearState();
+            return isInvalid ? entityName : undefined;
+        }
+
         function getLanguageVariant(scriptKind: ScriptKind) {
             // .tsx and .jsx files are treated as jsx language variant.
             return scriptKind === ScriptKind.TSX || scriptKind === ScriptKind.JSX || scriptKind === ScriptKind.JS ? LanguageVariant.JSX : LanguageVariant.Standard;
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index cb7efc49bf3aa..213e6a95ab173 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1674,6 +1674,9 @@ namespace ts {
                 if (options.reactNamespace) {
                     programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Option_0_cannot_be_specified_with_option_1, "reactNamespace", "jsxFactory"));
                 }
+                if (!parseIsolatedEntityName(options.jsxFactory, languageVersion)) {
+                    programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Invalid_value_for_jsxFactory_0_is_not_a_valid_identifier_or_qualified_name, options.jsxFactory));
+                }
             }
             else if (options.reactNamespace && !isIdentifierText(options.reactNamespace, languageVersion)) {
                 programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Invalid_value_for_reactNamespace_0_is_not_a_valid_identifier, options.reactNamespace));
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index a6e1ffad7f71e..b227a0d8fe657 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -1768,7 +1768,7 @@ namespace Harness {
         }
 
         // Regex for parsing options in the format "@Alpha: Value of any sort"
-        const optionRegex = /^[\/]{2}\s*@(\w+)\s*:\s*(\S*)/gm;  // multiple matches on multiple lines
+        const optionRegex = /^[\/]{2}\s*@(\w+)\s*:\s*([^\r\n]*)/gm;  // multiple matches on multiple lines
 
         function extractCompilerSettings(content: string): CompilerSettings {
             const opts: CompilerSettings = {};
@@ -1777,7 +1777,7 @@ namespace Harness {
             /* tslint:disable:no-null-keyword */
             while ((match = optionRegex.exec(content)) !== null) {
             /* tslint:enable:no-null-keyword */
-                opts[match[1]] = match[2];
+                opts[match[1]] = match[2].trim();
             }
 
             return opts;
@@ -1805,7 +1805,7 @@ namespace Harness {
                     // Comment line, check for global/file @options and record them
                     optionRegex.lastIndex = 0;
                     const metaDataName = testMetaData[1].toLowerCase();
-                    currentFileOptions[testMetaData[1]] = testMetaData[2];
+                    currentFileOptions[testMetaData[1]] = testMetaData[2].trim();
                     if (metaDataName !== "filename") {
                         continue;
                     }
@@ -1825,12 +1825,12 @@ namespace Harness {
                         // Reset local data
                         currentFileContent = undefined;
                         currentFileOptions = {};
-                        currentFileName = testMetaData[2];
+                        currentFileName = testMetaData[2].trim();
                         refs = [];
                     }
                     else {
                         // First metadata marker in the file
-                        currentFileName = testMetaData[2];
+                        currentFileName = testMetaData[2].trim();
                     }
                 }
                 else {
diff --git a/tests/baselines/reference/jsxFactoryIdentifier.errors.txt b/tests/baselines/reference/jsxFactoryIdentifier.errors.txt
new file mode 100644
index 0000000000000..e0cb485cf7ff8
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifier.errors.txt
@@ -0,0 +1,57 @@
+tests/cases/compiler/test.tsx(12,5): error TS2304: Cannot find name 'React'.
+tests/cases/compiler/test.tsx(13,5): error TS2304: Cannot find name 'React'.
+
+
+==== tests/cases/compiler/Element.ts (0 errors) ====
+    
+    declare namespace JSX {
+        interface Element {
+            name: string;
+            isIntrinsic: boolean;
+            isCustomElement: boolean;
+            toString(renderId?: number): string;
+            bindDOM(renderId?: number): number;
+            resetComponent(): void;
+            instantiateComponents(renderId?: number): number;
+            props: any;
+        }
+    }
+    export namespace Element {
+        export function isElement(el: any): el is JSX.Element {
+            return el.markAsChildOfRootElement !== undefined;
+        }
+    
+        export function createElement(args: any[]) {
+    
+            return {
+            }
+        }
+    }
+    
+    export let createElement = Element.createElement;
+    
+    function toCamelCase(text: string): string {
+        return text[0].toLowerCase() + text.substring(1);
+    }
+    
+==== tests/cases/compiler/test.tsx (2 errors) ====
+    import { Element} from './Element';
+    let createElement = Element.createElement;
+    let c: {
+    	a?: {
+    		b: string
+    	}
+    };
+    
+    class A {
+    	view() {
+    		return [
+    			<meta content="helloworld"></meta>,
+    			 ~~~~
+!!! error TS2304: Cannot find name 'React'.
+    			<meta content={c.a!.b}></meta>
+    			 ~~~~
+!!! error TS2304: Cannot find name 'React'.
+    		];
+    	}
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryIdentifier.js b/tests/baselines/reference/jsxFactoryIdentifier.js
new file mode 100644
index 0000000000000..13abba537518e
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifier.js
@@ -0,0 +1,82 @@
+//// [tests/cases/compiler/jsxFactoryIdentifier.ts] ////
+
+//// [Element.ts]
+
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+//// [test.tsx]
+import { Element} from './Element';
+let createElement = Element.createElement;
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
+
+//// [Element.js]
+"use strict";
+var Element;
+(function (Element) {
+    function isElement(el) {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+    Element.isElement = isElement;
+    function createElement(args) {
+        return {};
+    }
+    Element.createElement = createElement;
+})(Element = exports.Element || (exports.Element = {}));
+exports.createElement = Element.createElement;
+function toCamelCase(text) {
+    return text[0].toLowerCase() + text.substring(1);
+}
+//// [test.js]
+"use strict";
+const Element_1 = require("./Element");
+let createElement = Element_1.Element.createElement;
+let c;
+class A {
+    view() {
+        return [
+            React.createElement("meta", { content: "helloworld" }),
+            React.createElement("meta", { content: c.a.b })
+        ];
+    }
+}
diff --git a/tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName.errors.txt b/tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName.errors.txt
new file mode 100644
index 0000000000000..e14f5f988f83f
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName.errors.txt
@@ -0,0 +1,59 @@
+error TS5067: Invalid value for 'jsxFactory'. 'Element.createElement=' is not a valid identifier or qualified-name.
+tests/cases/compiler/test.tsx(12,5): error TS2304: Cannot find name 'React'.
+tests/cases/compiler/test.tsx(13,5): error TS2304: Cannot find name 'React'.
+
+
+!!! error TS5067: Invalid value for 'jsxFactory'. 'Element.createElement=' is not a valid identifier or qualified-name.
+==== tests/cases/compiler/Element.ts (0 errors) ====
+    
+    declare namespace JSX {
+        interface Element {
+            name: string;
+            isIntrinsic: boolean;
+            isCustomElement: boolean;
+            toString(renderId?: number): string;
+            bindDOM(renderId?: number): number;
+            resetComponent(): void;
+            instantiateComponents(renderId?: number): number;
+            props: any;
+        }
+    }
+    export namespace Element {
+        export function isElement(el: any): el is JSX.Element {
+            return el.markAsChildOfRootElement !== undefined;
+        }
+    
+        export function createElement(args: any[]) {
+    
+            return {
+            }
+        }
+    }
+    
+    export let createElement = Element.createElement;
+    
+    function toCamelCase(text: string): string {
+        return text[0].toLowerCase() + text.substring(1);
+    }
+    
+==== tests/cases/compiler/test.tsx (2 errors) ====
+    import { Element} from './Element';
+    
+    let c: {
+    	a?: {
+    		b: string
+    	}
+    };
+    
+    class A {
+    	view() {
+    		return [
+    			<meta content="helloworld"></meta>,
+    			 ~~~~
+!!! error TS2304: Cannot find name 'React'.
+    			<meta content={c.a!.b}></meta>
+    			 ~~~~
+!!! error TS2304: Cannot find name 'React'.
+    		];
+    	}
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName.js b/tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName.js
new file mode 100644
index 0000000000000..90bb675442ac6
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName.js
@@ -0,0 +1,80 @@
+//// [tests/cases/compiler/jsxFactoryNotIdentifierOrQualifiedName.ts] ////
+
+//// [Element.ts]
+
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+//// [test.tsx]
+import { Element} from './Element';
+
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
+
+//// [Element.js]
+"use strict";
+var Element;
+(function (Element) {
+    function isElement(el) {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+    Element.isElement = isElement;
+    function createElement(args) {
+        return {};
+    }
+    Element.createElement = createElement;
+})(Element = exports.Element || (exports.Element = {}));
+exports.createElement = Element.createElement;
+function toCamelCase(text) {
+    return text[0].toLowerCase() + text.substring(1);
+}
+//// [test.js]
+"use strict";
+let c;
+class A {
+    view() {
+        return [
+            React.createElement("meta", { content: "helloworld" }),
+            React.createElement("meta", { content: c.a.b })
+        ];
+    }
+}
diff --git a/tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName2.errors.txt b/tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName2.errors.txt
new file mode 100644
index 0000000000000..1c33f3a7a5139
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName2.errors.txt
@@ -0,0 +1,59 @@
+error TS5067: Invalid value for 'jsxFactory'. 'id1 id2' is not a valid identifier or qualified-name.
+tests/cases/compiler/test.tsx(12,5): error TS2304: Cannot find name 'React'.
+tests/cases/compiler/test.tsx(13,5): error TS2304: Cannot find name 'React'.
+
+
+!!! error TS5067: Invalid value for 'jsxFactory'. 'id1 id2' is not a valid identifier or qualified-name.
+==== tests/cases/compiler/Element.ts (0 errors) ====
+    
+    declare namespace JSX {
+        interface Element {
+            name: string;
+            isIntrinsic: boolean;
+            isCustomElement: boolean;
+            toString(renderId?: number): string;
+            bindDOM(renderId?: number): number;
+            resetComponent(): void;
+            instantiateComponents(renderId?: number): number;
+            props: any;
+        }
+    }
+    export namespace Element {
+        export function isElement(el: any): el is JSX.Element {
+            return el.markAsChildOfRootElement !== undefined;
+        }
+    
+        export function createElement(args: any[]) {
+    
+            return {
+            }
+        }
+    }
+    
+    export let createElement = Element.createElement;
+    
+    function toCamelCase(text: string): string {
+        return text[0].toLowerCase() + text.substring(1);
+    }
+    
+==== tests/cases/compiler/test.tsx (2 errors) ====
+    import { Element} from './Element';
+    
+    let c: {
+    	a?: {
+    		b: string
+    	}
+    };
+    
+    class A {
+    	view() {
+    		return [
+    			<meta content="helloworld"></meta>,
+    			 ~~~~
+!!! error TS2304: Cannot find name 'React'.
+    			<meta content={c.a!.b}></meta>
+    			 ~~~~
+!!! error TS2304: Cannot find name 'React'.
+    		];
+    	}
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName2.js b/tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName2.js
new file mode 100644
index 0000000000000..0bc0c6e57c54c
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName2.js
@@ -0,0 +1,80 @@
+//// [tests/cases/compiler/jsxFactoryNotIdentifierOrQualifiedName2.ts] ////
+
+//// [Element.ts]
+
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+//// [test.tsx]
+import { Element} from './Element';
+
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
+
+//// [Element.js]
+"use strict";
+var Element;
+(function (Element) {
+    function isElement(el) {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+    Element.isElement = isElement;
+    function createElement(args) {
+        return {};
+    }
+    Element.createElement = createElement;
+})(Element = exports.Element || (exports.Element = {}));
+exports.createElement = Element.createElement;
+function toCamelCase(text) {
+    return text[0].toLowerCase() + text.substring(1);
+}
+//// [test.js]
+"use strict";
+let c;
+class A {
+    view() {
+        return [
+            React.createElement("meta", { content: "helloworld" }),
+            React.createElement("meta", { content: c.a.b })
+        ];
+    }
+}
diff --git a/tests/baselines/reference/jsxFactoryQualifiedName.errors.txt b/tests/baselines/reference/jsxFactoryQualifiedName.errors.txt
new file mode 100644
index 0000000000000..32c8500ea3b7a
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryQualifiedName.errors.txt
@@ -0,0 +1,57 @@
+tests/cases/compiler/test.tsx(12,5): error TS2304: Cannot find name 'React'.
+tests/cases/compiler/test.tsx(13,5): error TS2304: Cannot find name 'React'.
+
+
+==== tests/cases/compiler/Element.ts (0 errors) ====
+    
+    declare namespace JSX {
+        interface Element {
+            name: string;
+            isIntrinsic: boolean;
+            isCustomElement: boolean;
+            toString(renderId?: number): string;
+            bindDOM(renderId?: number): number;
+            resetComponent(): void;
+            instantiateComponents(renderId?: number): number;
+            props: any;
+        }
+    }
+    export namespace Element {
+        export function isElement(el: any): el is JSX.Element {
+            return el.markAsChildOfRootElement !== undefined;
+        }
+    
+        export function createElement(args: any[]) {
+    
+            return {
+            }
+        }
+    }
+    
+    export let createElement = Element.createElement;
+    
+    function toCamelCase(text: string): string {
+        return text[0].toLowerCase() + text.substring(1);
+    }
+    
+==== tests/cases/compiler/test.tsx (2 errors) ====
+    import { Element} from './Element';
+    
+    let c: {
+    	a?: {
+    		b: string
+    	}
+    };
+    
+    class A {
+    	view() {
+    		return [
+    			<meta content="helloworld"></meta>,
+    			 ~~~~
+!!! error TS2304: Cannot find name 'React'.
+    			<meta content={c.a!.b}></meta>
+    			 ~~~~
+!!! error TS2304: Cannot find name 'React'.
+    		];
+    	}
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryQualifiedName.js b/tests/baselines/reference/jsxFactoryQualifiedName.js
new file mode 100644
index 0000000000000..aec6614bf01b0
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryQualifiedName.js
@@ -0,0 +1,80 @@
+//// [tests/cases/compiler/jsxFactoryQualifiedName.ts] ////
+
+//// [Element.ts]
+
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+//// [test.tsx]
+import { Element} from './Element';
+
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
+
+//// [Element.js]
+"use strict";
+var Element;
+(function (Element) {
+    function isElement(el) {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+    Element.isElement = isElement;
+    function createElement(args) {
+        return {};
+    }
+    Element.createElement = createElement;
+})(Element = exports.Element || (exports.Element = {}));
+exports.createElement = Element.createElement;
+function toCamelCase(text) {
+    return text[0].toLowerCase() + text.substring(1);
+}
+//// [test.js]
+"use strict";
+let c;
+class A {
+    view() {
+        return [
+            React.createElement("meta", { content: "helloworld" }),
+            React.createElement("meta", { content: c.a.b })
+        ];
+    }
+}
diff --git a/tests/cases/compiler/jsxFactoryIdentifier.ts b/tests/cases/compiler/jsxFactoryIdentifier.ts
new file mode 100644
index 0000000000000..9531abeeebfaa
--- /dev/null
+++ b/tests/cases/compiler/jsxFactoryIdentifier.ts
@@ -0,0 +1,53 @@
+//@jsx: react
+//@target: es6
+//@module: commonjs
+//@jsxFactory: createElement
+
+// @filename: Element.ts
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+// @filename: test.tsx
+import { Element} from './Element';
+let createElement = Element.createElement;
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/jsxFactoryNotIdentifierOrQualifiedName.ts b/tests/cases/compiler/jsxFactoryNotIdentifierOrQualifiedName.ts
new file mode 100644
index 0000000000000..6f7c584d2320d
--- /dev/null
+++ b/tests/cases/compiler/jsxFactoryNotIdentifierOrQualifiedName.ts
@@ -0,0 +1,53 @@
+//@jsx: react
+//@target: es6
+//@module: commonjs
+//@jsxFactory: Element.createElement=
+
+// @filename: Element.ts
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+// @filename: test.tsx
+import { Element} from './Element';
+
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/jsxFactoryNotIdentifierOrQualifiedName2.ts b/tests/cases/compiler/jsxFactoryNotIdentifierOrQualifiedName2.ts
new file mode 100644
index 0000000000000..610063f7d341b
--- /dev/null
+++ b/tests/cases/compiler/jsxFactoryNotIdentifierOrQualifiedName2.ts
@@ -0,0 +1,53 @@
+//@jsx: react
+//@target: es6
+//@module: commonjs
+//@jsxFactory: id1 id2
+
+// @filename: Element.ts
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+// @filename: test.tsx
+import { Element} from './Element';
+
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/jsxFactoryQualifiedName.ts b/tests/cases/compiler/jsxFactoryQualifiedName.ts
new file mode 100644
index 0000000000000..c8d9317138b35
--- /dev/null
+++ b/tests/cases/compiler/jsxFactoryQualifiedName.ts
@@ -0,0 +1,53 @@
+//@jsx: react
+//@target: es6
+//@module: commonjs
+//@jsxFactory: Element.createElement
+
+// @filename: Element.ts
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+// @filename: test.tsx
+import { Element} from './Element';
+
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
\ No newline at end of file

From 06affa6672bc3b11e72dff76b986983fc7f2e72d Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Wed, 9 Nov 2016 13:15:13 -0800
Subject: [PATCH 210/224] Resolve first identifier of the jsxFactory as part of
 type check

---
 src/compiler/checker.ts                       |  23 ++-
 src/compiler/program.ts                       |   9 +-
 src/compiler/types.ts                         |   2 +
 .../reference/jsxFactoryIdentifier.errors.txt |  57 -------
 .../reference/jsxFactoryIdentifier.symbols    | 125 ++++++++++++++++
 .../reference/jsxFactoryIdentifier.types      | 140 ++++++++++++++++++
 .../jsxFactoryQualifiedName.errors.txt        |  57 -------
 .../reference/jsxFactoryQualifiedName.js      |   1 +
 .../reference/jsxFactoryQualifiedName.symbols | 119 +++++++++++++++
 .../reference/jsxFactoryQualifiedName.types   | 134 +++++++++++++++++
 10 files changed, 548 insertions(+), 119 deletions(-)
 delete mode 100644 tests/baselines/reference/jsxFactoryIdentifier.errors.txt
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifier.symbols
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifier.types
 delete mode 100644 tests/baselines/reference/jsxFactoryQualifiedName.errors.txt
 create mode 100644 tests/baselines/reference/jsxFactoryQualifiedName.symbols
 create mode 100644 tests/baselines/reference/jsxFactoryQualifiedName.types

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 878323a41b878..6d5cee0362ee7 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -335,6 +335,7 @@ namespace ts {
         });
 
         let jsxElementType: Type;
+        let _jsxNamespace: string;
         /** Things we lazy load from the JSX namespace */
         const jsxTypes = createMap<Type>();
         const JsxNames = {
@@ -372,6 +373,22 @@ namespace ts {
 
         return checker;
 
+        function getJsxNamespace(): string {
+            if (_jsxNamespace === undefined) {
+                _jsxNamespace = "React";
+                if (compilerOptions.jsxFactory) {
+                    const jsxEntity = host.getJsxFactoryEntity();
+                    if (jsxEntity) {
+                        _jsxNamespace = getFirstIdentifier(jsxEntity).text;
+                    }
+                }
+                else if (compilerOptions.reactNamespace) {
+                    _jsxNamespace = compilerOptions.reactNamespace;
+                }
+            }
+            return _jsxNamespace;
+        }
+
         function getEmitResolver(sourceFile: SourceFile, cancellationToken: CancellationToken) {
             // Ensure we have all the type information in place for this file so that all the
             // emitter questions of this resolver will return the right information.
@@ -11337,10 +11354,10 @@ namespace ts {
         function checkJsxOpeningLikeElement(node: JsxOpeningLikeElement) {
             checkGrammarJsxElement(node);
             checkJsxPreconditions(node);
-            // The reactNamespace symbol should be marked as 'used' so we don't incorrectly elide its import. And if there
-            // is no reactNamespace symbol in scope when targeting React emit, we should issue an error.
+            // The reactNamespace/jsxFactory's root symbol should be marked as 'used' so we don't incorrectly elide its import. 
+            // And if there is no reactNamespace/jsxFactory's symbol in scope when targeting React emit, we should issue an error.
             const reactRefErr = compilerOptions.jsx === JsxEmit.React ? Diagnostics.Cannot_find_name_0 : undefined;
-            const reactNamespace = compilerOptions.reactNamespace ? compilerOptions.reactNamespace : "React";
+            const reactNamespace = getJsxNamespace();
             const reactSym = resolveName(node.tagName, reactNamespace, SymbolFlags.Value, reactRefErr, reactNamespace);
             if (reactSym) {
                 // Mark local symbol as referenced here because it might not have been marked
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 213e6a95ab173..a733d93a3dd21 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -329,6 +329,9 @@ namespace ts {
         // Map storing if there is emit blocking diagnostics for given input
         const hasEmitBlockingDiagnostics = createFileMap<boolean>(getCanonicalFileName);
 
+        // ReactNamespace and jsxFactory information
+        let jsxFactoryEntity: EntityName;
+
         let resolveModuleNamesWorker: (moduleNames: string[], containingFile: string) => ResolvedModuleFull[];
         if (host.resolveModuleNames) {
             resolveModuleNamesWorker = (moduleNames, containingFile) => host.resolveModuleNames(moduleNames, containingFile).map(resolved => {
@@ -421,7 +424,8 @@ namespace ts {
             getFileProcessingDiagnostics: () => fileProcessingDiagnostics,
             getResolvedTypeReferenceDirectives: () => resolvedTypeReferenceDirectives,
             isSourceFileFromExternalLibrary,
-            dropDiagnosticsProducingTypeChecker
+            dropDiagnosticsProducingTypeChecker,
+            getJsxFactoryEntity: () => jsxFactoryEntity
         };
 
         verifyCompilerOptions();
@@ -1674,7 +1678,8 @@ namespace ts {
                 if (options.reactNamespace) {
                     programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Option_0_cannot_be_specified_with_option_1, "reactNamespace", "jsxFactory"));
                 }
-                if (!parseIsolatedEntityName(options.jsxFactory, languageVersion)) {
+                jsxFactoryEntity = parseIsolatedEntityName(options.jsxFactory, languageVersion);
+                if (!jsxFactoryEntity) {
                     programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Invalid_value_for_jsxFactory_0_is_not_a_valid_identifier_or_qualified_name, options.jsxFactory));
                 }
             }
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 5ca542cfe1118..09d32ad817eb6 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2177,6 +2177,7 @@ namespace ts {
         getTypeChecker(): TypeChecker;
 
         /* @internal */ getCommonSourceDirectory(): string;
+        /* @internal */ getJsxFactoryEntity(): EntityName;
 
         // For testing purposes only.  Should not be used by any other consumers (including the
         // language service).
@@ -2250,6 +2251,7 @@ namespace ts {
     /* @internal */
     export interface TypeCheckerHost {
         getCompilerOptions(): CompilerOptions;
+        getJsxFactoryEntity(): EntityName;
 
         getSourceFiles(): SourceFile[];
         getSourceFile(fileName: string): SourceFile;
diff --git a/tests/baselines/reference/jsxFactoryIdentifier.errors.txt b/tests/baselines/reference/jsxFactoryIdentifier.errors.txt
deleted file mode 100644
index e0cb485cf7ff8..0000000000000
--- a/tests/baselines/reference/jsxFactoryIdentifier.errors.txt
+++ /dev/null
@@ -1,57 +0,0 @@
-tests/cases/compiler/test.tsx(12,5): error TS2304: Cannot find name 'React'.
-tests/cases/compiler/test.tsx(13,5): error TS2304: Cannot find name 'React'.
-
-
-==== tests/cases/compiler/Element.ts (0 errors) ====
-    
-    declare namespace JSX {
-        interface Element {
-            name: string;
-            isIntrinsic: boolean;
-            isCustomElement: boolean;
-            toString(renderId?: number): string;
-            bindDOM(renderId?: number): number;
-            resetComponent(): void;
-            instantiateComponents(renderId?: number): number;
-            props: any;
-        }
-    }
-    export namespace Element {
-        export function isElement(el: any): el is JSX.Element {
-            return el.markAsChildOfRootElement !== undefined;
-        }
-    
-        export function createElement(args: any[]) {
-    
-            return {
-            }
-        }
-    }
-    
-    export let createElement = Element.createElement;
-    
-    function toCamelCase(text: string): string {
-        return text[0].toLowerCase() + text.substring(1);
-    }
-    
-==== tests/cases/compiler/test.tsx (2 errors) ====
-    import { Element} from './Element';
-    let createElement = Element.createElement;
-    let c: {
-    	a?: {
-    		b: string
-    	}
-    };
-    
-    class A {
-    	view() {
-    		return [
-    			<meta content="helloworld"></meta>,
-    			 ~~~~
-!!! error TS2304: Cannot find name 'React'.
-    			<meta content={c.a!.b}></meta>
-    			 ~~~~
-!!! error TS2304: Cannot find name 'React'.
-    		];
-    	}
-    }
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryIdentifier.symbols b/tests/baselines/reference/jsxFactoryIdentifier.symbols
new file mode 100644
index 0000000000000..0d0f1e8049097
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifier.symbols
@@ -0,0 +1,125 @@
+=== tests/cases/compiler/Element.ts ===
+
+declare namespace JSX {
+>JSX : Symbol(JSX, Decl(Element.ts, 0, 0))
+
+    interface Element {
+>Element : Symbol(Element, Decl(Element.ts, 1, 23))
+
+        name: string;
+>name : Symbol(Element.name, Decl(Element.ts, 2, 23))
+
+        isIntrinsic: boolean;
+>isIntrinsic : Symbol(Element.isIntrinsic, Decl(Element.ts, 3, 21))
+
+        isCustomElement: boolean;
+>isCustomElement : Symbol(Element.isCustomElement, Decl(Element.ts, 4, 29))
+
+        toString(renderId?: number): string;
+>toString : Symbol(Element.toString, Decl(Element.ts, 5, 33))
+>renderId : Symbol(renderId, Decl(Element.ts, 6, 17))
+
+        bindDOM(renderId?: number): number;
+>bindDOM : Symbol(Element.bindDOM, Decl(Element.ts, 6, 44))
+>renderId : Symbol(renderId, Decl(Element.ts, 7, 16))
+
+        resetComponent(): void;
+>resetComponent : Symbol(Element.resetComponent, Decl(Element.ts, 7, 43))
+
+        instantiateComponents(renderId?: number): number;
+>instantiateComponents : Symbol(Element.instantiateComponents, Decl(Element.ts, 8, 31))
+>renderId : Symbol(renderId, Decl(Element.ts, 9, 30))
+
+        props: any;
+>props : Symbol(Element.props, Decl(Element.ts, 9, 57))
+    }
+}
+export namespace Element {
+>Element : Symbol(Element, Decl(Element.ts, 12, 1))
+
+    export function isElement(el: any): el is JSX.Element {
+>isElement : Symbol(isElement, Decl(Element.ts, 13, 26))
+>el : Symbol(el, Decl(Element.ts, 14, 30))
+>el : Symbol(el, Decl(Element.ts, 14, 30))
+>JSX : Symbol(JSX, Decl(Element.ts, 0, 0))
+>Element : Symbol(JSX.Element, Decl(Element.ts, 1, 23))
+
+        return el.markAsChildOfRootElement !== undefined;
+>el : Symbol(el, Decl(Element.ts, 14, 30))
+>undefined : Symbol(undefined)
+    }
+
+    export function createElement(args: any[]) {
+>createElement : Symbol(createElement, Decl(Element.ts, 16, 5))
+>args : Symbol(args, Decl(Element.ts, 18, 34))
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+>createElement : Symbol(createElement, Decl(Element.ts, 25, 10))
+>Element.createElement : Symbol(Element.createElement, Decl(Element.ts, 16, 5))
+>Element : Symbol(Element, Decl(Element.ts, 12, 1))
+>createElement : Symbol(Element.createElement, Decl(Element.ts, 16, 5))
+
+function toCamelCase(text: string): string {
+>toCamelCase : Symbol(toCamelCase, Decl(Element.ts, 25, 49))
+>text : Symbol(text, Decl(Element.ts, 27, 21))
+
+    return text[0].toLowerCase() + text.substring(1);
+>text[0].toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
+>text : Symbol(text, Decl(Element.ts, 27, 21))
+>toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
+>text.substring : Symbol(String.substring, Decl(lib.es5.d.ts, --, --))
+>text : Symbol(text, Decl(Element.ts, 27, 21))
+>substring : Symbol(String.substring, Decl(lib.es5.d.ts, --, --))
+}
+
+=== tests/cases/compiler/test.tsx ===
+import { Element} from './Element';
+>Element : Symbol(Element, Decl(test.tsx, 0, 8))
+
+let createElement = Element.createElement;
+>createElement : Symbol(createElement, Decl(test.tsx, 1, 3))
+>Element.createElement : Symbol(Element.createElement, Decl(Element.ts, 16, 5))
+>Element : Symbol(Element, Decl(test.tsx, 0, 8))
+>createElement : Symbol(Element.createElement, Decl(Element.ts, 16, 5))
+
+let c: {
+>c : Symbol(c, Decl(test.tsx, 2, 3))
+
+	a?: {
+>a : Symbol(a, Decl(test.tsx, 2, 8))
+
+		b: string
+>b : Symbol(b, Decl(test.tsx, 3, 6))
+	}
+};
+
+class A {
+>A : Symbol(A, Decl(test.tsx, 6, 2))
+
+	view() {
+>view : Symbol(A.view, Decl(test.tsx, 8, 9))
+
+		return [
+			<meta content="helloworld"></meta>,
+>meta : Symbol(unknown)
+>content : Symbol(unknown)
+>meta : Symbol(unknown)
+
+			<meta content={c.a!.b}></meta>
+>meta : Symbol(unknown)
+>content : Symbol(unknown)
+>c.a!.b : Symbol(b, Decl(test.tsx, 3, 6))
+>c.a : Symbol(a, Decl(test.tsx, 2, 8))
+>c : Symbol(c, Decl(test.tsx, 2, 3))
+>a : Symbol(a, Decl(test.tsx, 2, 8))
+>b : Symbol(b, Decl(test.tsx, 3, 6))
+>meta : Symbol(unknown)
+
+		];
+	}
+}
diff --git a/tests/baselines/reference/jsxFactoryIdentifier.types b/tests/baselines/reference/jsxFactoryIdentifier.types
new file mode 100644
index 0000000000000..c946c90559d1d
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifier.types
@@ -0,0 +1,140 @@
+=== tests/cases/compiler/Element.ts ===
+
+declare namespace JSX {
+>JSX : any
+
+    interface Element {
+>Element : Element
+
+        name: string;
+>name : string
+
+        isIntrinsic: boolean;
+>isIntrinsic : boolean
+
+        isCustomElement: boolean;
+>isCustomElement : boolean
+
+        toString(renderId?: number): string;
+>toString : (renderId?: number) => string
+>renderId : number
+
+        bindDOM(renderId?: number): number;
+>bindDOM : (renderId?: number) => number
+>renderId : number
+
+        resetComponent(): void;
+>resetComponent : () => void
+
+        instantiateComponents(renderId?: number): number;
+>instantiateComponents : (renderId?: number) => number
+>renderId : number
+
+        props: any;
+>props : any
+    }
+}
+export namespace Element {
+>Element : typeof Element
+
+    export function isElement(el: any): el is JSX.Element {
+>isElement : (el: any) => el is JSX.Element
+>el : any
+>el : any
+>JSX : any
+>Element : JSX.Element
+
+        return el.markAsChildOfRootElement !== undefined;
+>el.markAsChildOfRootElement !== undefined : boolean
+>el.markAsChildOfRootElement : any
+>el : any
+>markAsChildOfRootElement : any
+>undefined : undefined
+    }
+
+    export function createElement(args: any[]) {
+>createElement : (args: any[]) => {}
+>args : any[]
+
+        return {
+>{        } : {}
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+>createElement : (args: any[]) => {}
+>Element.createElement : (args: any[]) => {}
+>Element : typeof Element
+>createElement : (args: any[]) => {}
+
+function toCamelCase(text: string): string {
+>toCamelCase : (text: string) => string
+>text : string
+
+    return text[0].toLowerCase() + text.substring(1);
+>text[0].toLowerCase() + text.substring(1) : string
+>text[0].toLowerCase() : string
+>text[0].toLowerCase : () => string
+>text[0] : string
+>text : string
+>0 : 0
+>toLowerCase : () => string
+>text.substring(1) : string
+>text.substring : (start: number, end?: number) => string
+>text : string
+>substring : (start: number, end?: number) => string
+>1 : 1
+}
+
+=== tests/cases/compiler/test.tsx ===
+import { Element} from './Element';
+>Element : typeof Element
+
+let createElement = Element.createElement;
+>createElement : (args: any[]) => {}
+>Element.createElement : (args: any[]) => {}
+>Element : typeof Element
+>createElement : (args: any[]) => {}
+
+let c: {
+>c : { a?: { b: string; }; }
+
+	a?: {
+>a : { b: string; }
+
+		b: string
+>b : string
+	}
+};
+
+class A {
+>A : A
+
+	view() {
+>view : () => any[]
+
+		return [
+>[			<meta content="helloworld"></meta>,			<meta content={c.a!.b}></meta>		] : any[]
+
+			<meta content="helloworld"></meta>,
+><meta content="helloworld"></meta> : any
+>meta : any
+>content : any
+>meta : any
+
+			<meta content={c.a!.b}></meta>
+><meta content={c.a!.b}></meta> : any
+>meta : any
+>content : any
+>c.a!.b : string
+>c.a! : { b: string; }
+>c.a : { b: string; }
+>c : { a?: { b: string; }; }
+>a : { b: string; }
+>b : string
+>meta : any
+
+		];
+	}
+}
diff --git a/tests/baselines/reference/jsxFactoryQualifiedName.errors.txt b/tests/baselines/reference/jsxFactoryQualifiedName.errors.txt
deleted file mode 100644
index 32c8500ea3b7a..0000000000000
--- a/tests/baselines/reference/jsxFactoryQualifiedName.errors.txt
+++ /dev/null
@@ -1,57 +0,0 @@
-tests/cases/compiler/test.tsx(12,5): error TS2304: Cannot find name 'React'.
-tests/cases/compiler/test.tsx(13,5): error TS2304: Cannot find name 'React'.
-
-
-==== tests/cases/compiler/Element.ts (0 errors) ====
-    
-    declare namespace JSX {
-        interface Element {
-            name: string;
-            isIntrinsic: boolean;
-            isCustomElement: boolean;
-            toString(renderId?: number): string;
-            bindDOM(renderId?: number): number;
-            resetComponent(): void;
-            instantiateComponents(renderId?: number): number;
-            props: any;
-        }
-    }
-    export namespace Element {
-        export function isElement(el: any): el is JSX.Element {
-            return el.markAsChildOfRootElement !== undefined;
-        }
-    
-        export function createElement(args: any[]) {
-    
-            return {
-            }
-        }
-    }
-    
-    export let createElement = Element.createElement;
-    
-    function toCamelCase(text: string): string {
-        return text[0].toLowerCase() + text.substring(1);
-    }
-    
-==== tests/cases/compiler/test.tsx (2 errors) ====
-    import { Element} from './Element';
-    
-    let c: {
-    	a?: {
-    		b: string
-    	}
-    };
-    
-    class A {
-    	view() {
-    		return [
-    			<meta content="helloworld"></meta>,
-    			 ~~~~
-!!! error TS2304: Cannot find name 'React'.
-    			<meta content={c.a!.b}></meta>
-    			 ~~~~
-!!! error TS2304: Cannot find name 'React'.
-    		];
-    	}
-    }
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryQualifiedName.js b/tests/baselines/reference/jsxFactoryQualifiedName.js
index aec6614bf01b0..b5da232a3d426 100644
--- a/tests/baselines/reference/jsxFactoryQualifiedName.js
+++ b/tests/baselines/reference/jsxFactoryQualifiedName.js
@@ -69,6 +69,7 @@ function toCamelCase(text) {
 }
 //// [test.js]
 "use strict";
+const Element_1 = require("./Element");
 let c;
 class A {
     view() {
diff --git a/tests/baselines/reference/jsxFactoryQualifiedName.symbols b/tests/baselines/reference/jsxFactoryQualifiedName.symbols
new file mode 100644
index 0000000000000..16cd35d1ca323
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryQualifiedName.symbols
@@ -0,0 +1,119 @@
+=== tests/cases/compiler/Element.ts ===
+
+declare namespace JSX {
+>JSX : Symbol(JSX, Decl(Element.ts, 0, 0))
+
+    interface Element {
+>Element : Symbol(Element, Decl(Element.ts, 1, 23))
+
+        name: string;
+>name : Symbol(Element.name, Decl(Element.ts, 2, 23))
+
+        isIntrinsic: boolean;
+>isIntrinsic : Symbol(Element.isIntrinsic, Decl(Element.ts, 3, 21))
+
+        isCustomElement: boolean;
+>isCustomElement : Symbol(Element.isCustomElement, Decl(Element.ts, 4, 29))
+
+        toString(renderId?: number): string;
+>toString : Symbol(Element.toString, Decl(Element.ts, 5, 33))
+>renderId : Symbol(renderId, Decl(Element.ts, 6, 17))
+
+        bindDOM(renderId?: number): number;
+>bindDOM : Symbol(Element.bindDOM, Decl(Element.ts, 6, 44))
+>renderId : Symbol(renderId, Decl(Element.ts, 7, 16))
+
+        resetComponent(): void;
+>resetComponent : Symbol(Element.resetComponent, Decl(Element.ts, 7, 43))
+
+        instantiateComponents(renderId?: number): number;
+>instantiateComponents : Symbol(Element.instantiateComponents, Decl(Element.ts, 8, 31))
+>renderId : Symbol(renderId, Decl(Element.ts, 9, 30))
+
+        props: any;
+>props : Symbol(Element.props, Decl(Element.ts, 9, 57))
+    }
+}
+export namespace Element {
+>Element : Symbol(Element, Decl(Element.ts, 12, 1))
+
+    export function isElement(el: any): el is JSX.Element {
+>isElement : Symbol(isElement, Decl(Element.ts, 13, 26))
+>el : Symbol(el, Decl(Element.ts, 14, 30))
+>el : Symbol(el, Decl(Element.ts, 14, 30))
+>JSX : Symbol(JSX, Decl(Element.ts, 0, 0))
+>Element : Symbol(JSX.Element, Decl(Element.ts, 1, 23))
+
+        return el.markAsChildOfRootElement !== undefined;
+>el : Symbol(el, Decl(Element.ts, 14, 30))
+>undefined : Symbol(undefined)
+    }
+
+    export function createElement(args: any[]) {
+>createElement : Symbol(createElement, Decl(Element.ts, 16, 5))
+>args : Symbol(args, Decl(Element.ts, 18, 34))
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+>createElement : Symbol(createElement, Decl(Element.ts, 25, 10))
+>Element.createElement : Symbol(Element.createElement, Decl(Element.ts, 16, 5))
+>Element : Symbol(Element, Decl(Element.ts, 12, 1))
+>createElement : Symbol(Element.createElement, Decl(Element.ts, 16, 5))
+
+function toCamelCase(text: string): string {
+>toCamelCase : Symbol(toCamelCase, Decl(Element.ts, 25, 49))
+>text : Symbol(text, Decl(Element.ts, 27, 21))
+
+    return text[0].toLowerCase() + text.substring(1);
+>text[0].toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
+>text : Symbol(text, Decl(Element.ts, 27, 21))
+>toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
+>text.substring : Symbol(String.substring, Decl(lib.es5.d.ts, --, --))
+>text : Symbol(text, Decl(Element.ts, 27, 21))
+>substring : Symbol(String.substring, Decl(lib.es5.d.ts, --, --))
+}
+
+=== tests/cases/compiler/test.tsx ===
+import { Element} from './Element';
+>Element : Symbol(Element, Decl(test.tsx, 0, 8))
+
+let c: {
+>c : Symbol(c, Decl(test.tsx, 2, 3))
+
+	a?: {
+>a : Symbol(a, Decl(test.tsx, 2, 8))
+
+		b: string
+>b : Symbol(b, Decl(test.tsx, 3, 6))
+	}
+};
+
+class A {
+>A : Symbol(A, Decl(test.tsx, 6, 2))
+
+	view() {
+>view : Symbol(A.view, Decl(test.tsx, 8, 9))
+
+		return [
+			<meta content="helloworld"></meta>,
+>meta : Symbol(unknown)
+>content : Symbol(unknown)
+>meta : Symbol(unknown)
+
+			<meta content={c.a!.b}></meta>
+>meta : Symbol(unknown)
+>content : Symbol(unknown)
+>c.a!.b : Symbol(b, Decl(test.tsx, 3, 6))
+>c.a : Symbol(a, Decl(test.tsx, 2, 8))
+>c : Symbol(c, Decl(test.tsx, 2, 3))
+>a : Symbol(a, Decl(test.tsx, 2, 8))
+>b : Symbol(b, Decl(test.tsx, 3, 6))
+>meta : Symbol(unknown)
+
+		];
+	}
+}
diff --git a/tests/baselines/reference/jsxFactoryQualifiedName.types b/tests/baselines/reference/jsxFactoryQualifiedName.types
new file mode 100644
index 0000000000000..663ba4b5bfc43
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryQualifiedName.types
@@ -0,0 +1,134 @@
+=== tests/cases/compiler/Element.ts ===
+
+declare namespace JSX {
+>JSX : any
+
+    interface Element {
+>Element : Element
+
+        name: string;
+>name : string
+
+        isIntrinsic: boolean;
+>isIntrinsic : boolean
+
+        isCustomElement: boolean;
+>isCustomElement : boolean
+
+        toString(renderId?: number): string;
+>toString : (renderId?: number) => string
+>renderId : number
+
+        bindDOM(renderId?: number): number;
+>bindDOM : (renderId?: number) => number
+>renderId : number
+
+        resetComponent(): void;
+>resetComponent : () => void
+
+        instantiateComponents(renderId?: number): number;
+>instantiateComponents : (renderId?: number) => number
+>renderId : number
+
+        props: any;
+>props : any
+    }
+}
+export namespace Element {
+>Element : typeof Element
+
+    export function isElement(el: any): el is JSX.Element {
+>isElement : (el: any) => el is JSX.Element
+>el : any
+>el : any
+>JSX : any
+>Element : JSX.Element
+
+        return el.markAsChildOfRootElement !== undefined;
+>el.markAsChildOfRootElement !== undefined : boolean
+>el.markAsChildOfRootElement : any
+>el : any
+>markAsChildOfRootElement : any
+>undefined : undefined
+    }
+
+    export function createElement(args: any[]) {
+>createElement : (args: any[]) => {}
+>args : any[]
+
+        return {
+>{        } : {}
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+>createElement : (args: any[]) => {}
+>Element.createElement : (args: any[]) => {}
+>Element : typeof Element
+>createElement : (args: any[]) => {}
+
+function toCamelCase(text: string): string {
+>toCamelCase : (text: string) => string
+>text : string
+
+    return text[0].toLowerCase() + text.substring(1);
+>text[0].toLowerCase() + text.substring(1) : string
+>text[0].toLowerCase() : string
+>text[0].toLowerCase : () => string
+>text[0] : string
+>text : string
+>0 : 0
+>toLowerCase : () => string
+>text.substring(1) : string
+>text.substring : (start: number, end?: number) => string
+>text : string
+>substring : (start: number, end?: number) => string
+>1 : 1
+}
+
+=== tests/cases/compiler/test.tsx ===
+import { Element} from './Element';
+>Element : typeof Element
+
+let c: {
+>c : { a?: { b: string; }; }
+
+	a?: {
+>a : { b: string; }
+
+		b: string
+>b : string
+	}
+};
+
+class A {
+>A : A
+
+	view() {
+>view : () => any[]
+
+		return [
+>[			<meta content="helloworld"></meta>,			<meta content={c.a!.b}></meta>		] : any[]
+
+			<meta content="helloworld"></meta>,
+><meta content="helloworld"></meta> : any
+>meta : any
+>content : any
+>meta : any
+
+			<meta content={c.a!.b}></meta>
+><meta content={c.a!.b}></meta> : any
+>meta : any
+>content : any
+>c.a!.b : string
+>c.a! : { b: string; }
+>c.a : { b: string; }
+>c : { a?: { b: string; }; }
+>a : { b: string; }
+>b : string
+>meta : any
+
+		];
+	}
+}

From 3d6950d023b8c43b878292811189c5563128c8ec Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Wed, 9 Nov 2016 13:15:13 -0800
Subject: [PATCH 211/224] When emitting use jsx factory entity expression if
 provided

---
 src/compiler/factory.ts                       | 34 ++++++++++++++++---
 src/compiler/program.ts                       |  1 +
 src/compiler/transformers/jsx.ts              |  3 +-
 src/compiler/utilities.ts                     |  2 ++
 .../reference/jsxFactoryIdentifier.js         |  4 +--
 .../reference/jsxFactoryQualifiedName.js      |  4 +--
 6 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index c557e3514a5de..de6191f085ab7 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -1628,7 +1628,34 @@ namespace ts {
         return react;
     }
 
-    export function createReactCreateElement(reactNamespace: string, tagName: Expression, props: Expression, children: Expression[], parentElement: JsxOpeningLikeElement, location: TextRange): LeftHandSideExpression {
+    function createJsxFactoryExpressionFromEntityName(jsxFactory: EntityName, parent: JsxOpeningLikeElement): Expression {
+        if (isQualifiedName(jsxFactory)) {
+            return createPropertyAccess(
+                createJsxFactoryExpressionFromEntityName(
+                    jsxFactory.left,
+                    parent
+                ),
+                setEmitFlags(
+                    getMutableClone(jsxFactory.right),
+                    EmitFlags.NoSourceMap
+                )
+            );
+        }
+        else {
+            return createReactNamespace(jsxFactory.text, parent);
+        }
+    }
+
+    function createJsxFactoryExpression(jsxFactoryEntity: EntityName, reactNamespace: string, parent: JsxOpeningLikeElement): Expression {
+        return jsxFactoryEntity ?
+            createJsxFactoryExpressionFromEntityName(jsxFactoryEntity, parent) :
+            createPropertyAccess(
+                createReactNamespace(reactNamespace, parent),
+                "createElement"
+            );
+    }
+
+    export function createExpressionForJsxElement(jsxFactoryEntity: EntityName, reactNamespace: string, tagName: Expression, props: Expression, children: Expression[], parentElement: JsxOpeningLikeElement, location: TextRange): LeftHandSideExpression {
         const argumentsList = [tagName];
         if (props) {
             argumentsList.push(props);
@@ -1651,10 +1678,7 @@ namespace ts {
         }
 
         return createCall(
-            createPropertyAccess(
-                createReactNamespace(reactNamespace, parentElement),
-                "createElement"
-            ),
+            createJsxFactoryExpression(jsxFactoryEntity, reactNamespace, parentElement),
             /*typeArguments*/ undefined,
             argumentsList,
             location
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index a733d93a3dd21..90448d197d00e 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -731,6 +731,7 @@ namespace ts {
                 writeFile: writeFileCallback || (
                     (fileName, data, writeByteOrderMark, onError, sourceFiles) => host.writeFile(fileName, data, writeByteOrderMark, onError, sourceFiles)),
                 isEmitBlocked,
+                getJsxFactoryEntity: program.getJsxFactoryEntity,
             };
         }
 
diff --git a/src/compiler/transformers/jsx.ts b/src/compiler/transformers/jsx.ts
index 95a4016bb0aeb..874f4f6862f49 100644
--- a/src/compiler/transformers/jsx.ts
+++ b/src/compiler/transformers/jsx.ts
@@ -113,7 +113,8 @@ namespace ts {
                     || createAssignHelper(currentSourceFile.externalHelpersModuleName, segments);
             }
 
-            const element = createReactCreateElement(
+            const element = createExpressionForJsxElement(
+                context.getEmitHost().getJsxFactoryEntity(),
                 compilerOptions.reactNamespace,
                 tagName,
                 objectProperties,
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 299f91be6625c..826beccc7b12b 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -34,6 +34,8 @@ namespace ts {
         /* @internal */
         isSourceFileFromExternalLibrary(file: SourceFile): boolean;
 
+        /* @internal */
+        getJsxFactoryEntity(): EntityName;
         getCommonSourceDirectory(): string;
         getCanonicalFileName(fileName: string): string;
         getNewLine(): string;
diff --git a/tests/baselines/reference/jsxFactoryIdentifier.js b/tests/baselines/reference/jsxFactoryIdentifier.js
index 13abba537518e..8205e752abd33 100644
--- a/tests/baselines/reference/jsxFactoryIdentifier.js
+++ b/tests/baselines/reference/jsxFactoryIdentifier.js
@@ -75,8 +75,8 @@ let c;
 class A {
     view() {
         return [
-            React.createElement("meta", { content: "helloworld" }),
-            React.createElement("meta", { content: c.a.b })
+            createElement("meta", { content: "helloworld" }),
+            createElement("meta", { content: c.a.b })
         ];
     }
 }
diff --git a/tests/baselines/reference/jsxFactoryQualifiedName.js b/tests/baselines/reference/jsxFactoryQualifiedName.js
index b5da232a3d426..e5c7b04f76056 100644
--- a/tests/baselines/reference/jsxFactoryQualifiedName.js
+++ b/tests/baselines/reference/jsxFactoryQualifiedName.js
@@ -74,8 +74,8 @@ let c;
 class A {
     view() {
         return [
-            React.createElement("meta", { content: "helloworld" }),
-            React.createElement("meta", { content: c.a.b })
+            Element_1.Element.createElement("meta", { content: "helloworld" }),
+            Element_1.Element.createElement("meta", { content: c.a.b })
         ];
     }
 }

From 35e4c459f5749e3478160378c0c8ecbb128bb1d0 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Wed, 9 Nov 2016 13:15:13 -0800
Subject: [PATCH 212/224] Transpile unit test case

---
 src/harness/unittests/transpile.ts                            | 4 ++++
 .../reference/transpile/Supports setting jsxFactory.js        | 3 +++
 2 files changed, 7 insertions(+)
 create mode 100644 tests/baselines/reference/transpile/Supports setting jsxFactory.js

diff --git a/src/harness/unittests/transpile.ts b/src/harness/unittests/transpile.ts
index 35b4f80835024..20552ab9c2e14 100644
--- a/src/harness/unittests/transpile.ts
+++ b/src/harness/unittests/transpile.ts
@@ -385,6 +385,10 @@ var x = 0;`, {
             options: { compilerOptions: { reactNamespace: "react" }, fileName: "input.js", reportDiagnostics: true }
         });
 
+        transpilesCorrectly("Supports setting 'jsxFactory'", "x;", {
+            options: { compilerOptions: { jsxFactory: "createElement" }, fileName: "input.js", reportDiagnostics: true }
+        });
+
         transpilesCorrectly("Supports setting 'removeComments'", "x;", {
             options: { compilerOptions: { removeComments: true }, fileName: "input.js", reportDiagnostics: true }
         });
diff --git a/tests/baselines/reference/transpile/Supports setting jsxFactory.js b/tests/baselines/reference/transpile/Supports setting jsxFactory.js
new file mode 100644
index 0000000000000..8d91090453b8a
--- /dev/null
+++ b/tests/baselines/reference/transpile/Supports setting jsxFactory.js	
@@ -0,0 +1,3 @@
+"use strict";
+x;
+//# sourceMappingURL=input.js.map
\ No newline at end of file

From c6b1bbe12dc17fbd87d9a3c6215027853de028b4 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Wed, 9 Nov 2016 13:15:13 -0800
Subject: [PATCH 213/224] Enabled test case for source map

---
 .../reference/jsxFactoryIdentifier.js         |   3 +-
 .../reference/jsxFactoryIdentifier.js.map     |   3 +
 .../jsxFactoryIdentifier.sourcemap.txt        | 520 ++++++++++++++++++
 .../reference/jsxFactoryQualifiedName.js      |   3 +-
 .../reference/jsxFactoryQualifiedName.js.map  |   3 +
 .../jsxFactoryQualifiedName.sourcemap.txt     | 493 +++++++++++++++++
 tests/cases/compiler/jsxFactoryIdentifier.ts  |   1 +
 .../cases/compiler/jsxFactoryQualifiedName.ts |   1 +
 8 files changed, 1025 insertions(+), 2 deletions(-)
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifier.js.map
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifier.sourcemap.txt
 create mode 100644 tests/baselines/reference/jsxFactoryQualifiedName.js.map
 create mode 100644 tests/baselines/reference/jsxFactoryQualifiedName.sourcemap.txt

diff --git a/tests/baselines/reference/jsxFactoryIdentifier.js b/tests/baselines/reference/jsxFactoryIdentifier.js
index 8205e752abd33..82c8f6410e65b 100644
--- a/tests/baselines/reference/jsxFactoryIdentifier.js
+++ b/tests/baselines/reference/jsxFactoryIdentifier.js
@@ -67,7 +67,7 @@ exports.createElement = Element.createElement;
 function toCamelCase(text) {
     return text[0].toLowerCase() + text.substring(1);
 }
-//// [test.js]
+//# sourceMappingURL=Element.js.map//// [test.js]
 "use strict";
 const Element_1 = require("./Element");
 let createElement = Element_1.Element.createElement;
@@ -80,3 +80,4 @@ class A {
         ];
     }
 }
+//# sourceMappingURL=test.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryIdentifier.js.map b/tests/baselines/reference/jsxFactoryIdentifier.js.map
new file mode 100644
index 0000000000000..cad196b8ba5ee
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifier.js.map
@@ -0,0 +1,3 @@
+//// [Element.js.map]
+{"version":3,"file":"Element.js","sourceRoot":"","sources":["Element.ts"],"names":[],"mappings":";AAaA,IAAiB,OAAO,CAUvB;AAVD,WAAiB,OAAO;IACpB,mBAA0B,EAAO;QAC7B,MAAM,CAAC,EAAE,CAAC,wBAAwB,KAAK,SAAS,CAAC;IACrD,CAAC;IAFe,iBAAS,YAExB,CAAA;IAED,uBAA8B,IAAW;QAErC,MAAM,CAAC,EACN,CAAA;IACL,CAAC;IAJe,qBAAa,gBAI5B,CAAA;AACL,CAAC,EAVgB,OAAO,GAAP,eAAO,KAAP,eAAO,QAUvB;AAEU,QAAA,aAAa,GAAG,OAAO,CAAC,aAAa,CAAC;AAEjD,qBAAqB,IAAY;IAC7B,MAAM,CAAC,IAAI,CAAC,CAAC,CAAC,CAAC,WAAW,EAAE,GAAG,IAAI,CAAC,SAAS,CAAC,CAAC,CAAC,CAAC;AACrD,CAAC"}//// [test.js.map]
+{"version":3,"file":"test.js","sourceRoot":"","sources":["test.tsx"],"names":[],"mappings":";AAAA,uCAAmC;AACnC,IAAI,aAAa,GAAG,iBAAO,CAAC,aAAa,CAAC;AAC1C,IAAI,CAIH,CAAC;AAEF;IACC,IAAI;QACH,MAAM,CAAC;YACN,wBAAM,OAAO,EAAC,YAAY,GAAQ;YAClC,wBAAM,OAAO,EAAE,CAAC,CAAC,CAAE,CAAC,CAAC,GAAS;SAC9B,CAAC;IACH,CAAC;CACD"}
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryIdentifier.sourcemap.txt b/tests/baselines/reference/jsxFactoryIdentifier.sourcemap.txt
new file mode 100644
index 0000000000000..a4ddc8c050b68
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifier.sourcemap.txt
@@ -0,0 +1,520 @@
+===================================================================
+JsFile: Element.js
+mapUrl: Element.js.map
+sourceRoot: 
+sources: Element.ts
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/Element.js
+sourceFile:Element.ts
+-------------------------------------------------------------------
+>>>"use strict";
+>>>var Element;
+1 >
+2 >^^^^
+3 >    ^^^^^^^
+4 >           ^
+5 >            ^^^^^^^^^^->
+1 >
+  >declare namespace JSX {
+  >    interface Element {
+  >        name: string;
+  >        isIntrinsic: boolean;
+  >        isCustomElement: boolean;
+  >        toString(renderId?: number): string;
+  >        bindDOM(renderId?: number): number;
+  >        resetComponent(): void;
+  >        instantiateComponents(renderId?: number): number;
+  >        props: any;
+  >    }
+  >}
+  >
+2 >export namespace 
+3 >    Element
+4 >            {
+  >               export function isElement(el: any): el is JSX.Element {
+  >                   return el.markAsChildOfRootElement !== undefined;
+  >               }
+  >           
+  >               export function createElement(args: any[]) {
+  >           
+  >                   return {
+  >                   }
+  >               }
+  >           }
+1 >Emitted(2, 1) Source(14, 1) + SourceIndex(0)
+2 >Emitted(2, 5) Source(14, 18) + SourceIndex(0)
+3 >Emitted(2, 12) Source(14, 25) + SourceIndex(0)
+4 >Emitted(2, 13) Source(24, 2) + SourceIndex(0)
+---
+>>>(function (Element) {
+1->
+2 >^^^^^^^^^^^
+3 >           ^^^^^^^
+4 >                  ^^^^^^^^^^^->
+1->
+2 >export namespace 
+3 >           Element
+1->Emitted(3, 1) Source(14, 1) + SourceIndex(0)
+2 >Emitted(3, 12) Source(14, 18) + SourceIndex(0)
+3 >Emitted(3, 19) Source(14, 25) + SourceIndex(0)
+---
+>>>    function isElement(el) {
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^
+3 >                       ^^
+4 >                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1-> {
+  >    
+2 >    export function isElement(
+3 >                       el: any
+1->Emitted(4, 5) Source(15, 5) + SourceIndex(0)
+2 >Emitted(4, 24) Source(15, 31) + SourceIndex(0)
+3 >Emitted(4, 26) Source(15, 38) + SourceIndex(0)
+---
+>>>        return el.markAsChildOfRootElement !== undefined;
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^
+5 >                 ^
+6 >                  ^^^^^^^^^^^^^^^^^^^^^^^^
+7 >                                          ^^^^^
+8 >                                               ^^^^^^^^^
+9 >                                                        ^
+1->): el is JSX.Element {
+  >        
+2 >        return
+3 >               
+4 >               el
+5 >                 .
+6 >                  markAsChildOfRootElement
+7 >                                           !== 
+8 >                                               undefined
+9 >                                                        ;
+1->Emitted(5, 9) Source(16, 9) + SourceIndex(0)
+2 >Emitted(5, 15) Source(16, 15) + SourceIndex(0)
+3 >Emitted(5, 16) Source(16, 16) + SourceIndex(0)
+4 >Emitted(5, 18) Source(16, 18) + SourceIndex(0)
+5 >Emitted(5, 19) Source(16, 19) + SourceIndex(0)
+6 >Emitted(5, 43) Source(16, 43) + SourceIndex(0)
+7 >Emitted(5, 48) Source(16, 48) + SourceIndex(0)
+8 >Emitted(5, 57) Source(16, 57) + SourceIndex(0)
+9 >Emitted(5, 58) Source(16, 58) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+3 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >    
+2 >    }
+1 >Emitted(6, 5) Source(17, 5) + SourceIndex(0)
+2 >Emitted(6, 6) Source(17, 6) + SourceIndex(0)
+---
+>>>    Element.isElement = isElement;
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^
+3 >                     ^^^^^^^^^^^^
+4 >                                 ^
+5 >                                  ^->
+1->
+2 >    isElement
+3 >                     (el: any): el is JSX.Element {
+  >                             return el.markAsChildOfRootElement !== undefined;
+  >                         }
+4 >                                 
+1->Emitted(7, 5) Source(15, 21) + SourceIndex(0)
+2 >Emitted(7, 22) Source(15, 30) + SourceIndex(0)
+3 >Emitted(7, 34) Source(17, 6) + SourceIndex(0)
+4 >Emitted(7, 35) Source(17, 6) + SourceIndex(0)
+---
+>>>    function createElement(args) {
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^^^^^
+3 >                           ^^^^
+1->
+  >
+  >    
+2 >    export function createElement(
+3 >                           args: any[]
+1->Emitted(8, 5) Source(19, 5) + SourceIndex(0)
+2 >Emitted(8, 28) Source(19, 35) + SourceIndex(0)
+3 >Emitted(8, 32) Source(19, 46) + SourceIndex(0)
+---
+>>>        return {};
+1 >^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^
+5 >                 ^
+1 >) {
+  >
+  >        
+2 >        return
+3 >               
+4 >               {
+  >                       }
+5 >                 
+1 >Emitted(9, 9) Source(21, 9) + SourceIndex(0)
+2 >Emitted(9, 15) Source(21, 15) + SourceIndex(0)
+3 >Emitted(9, 16) Source(21, 16) + SourceIndex(0)
+4 >Emitted(9, 18) Source(22, 10) + SourceIndex(0)
+5 >Emitted(9, 19) Source(22, 10) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+3 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >    
+2 >    }
+1 >Emitted(10, 5) Source(23, 5) + SourceIndex(0)
+2 >Emitted(10, 6) Source(23, 6) + SourceIndex(0)
+---
+>>>    Element.createElement = createElement;
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^^^
+3 >                         ^^^^^^^^^^^^^^^^
+4 >                                         ^
+5 >                                          ^^^^^^^^^^^^^^^->
+1->
+2 >    createElement
+3 >                         (args: any[]) {
+  >                         
+  >                                 return {
+  >                                 }
+  >                             }
+4 >                                         
+1->Emitted(11, 5) Source(19, 21) + SourceIndex(0)
+2 >Emitted(11, 26) Source(19, 34) + SourceIndex(0)
+3 >Emitted(11, 42) Source(23, 6) + SourceIndex(0)
+4 >Emitted(11, 43) Source(23, 6) + SourceIndex(0)
+---
+>>>})(Element = exports.Element || (exports.Element = {}));
+1->
+2 >^
+3 > ^^
+4 >   ^^^^^^^
+5 >          ^^^
+6 >             ^^^^^^^^^^^^^^^
+7 >                            ^^^^^
+8 >                                 ^^^^^^^^^^^^^^^
+9 >                                                ^^^^^^^^
+1->
+  >
+2 >}
+3 > 
+4 >   Element
+5 >          
+6 >             Element
+7 >                            
+8 >                                 Element
+9 >                                                 {
+  >                                                    export function isElement(el: any): el is JSX.Element {
+  >                                                        return el.markAsChildOfRootElement !== undefined;
+  >                                                    }
+  >                                                
+  >                                                    export function createElement(args: any[]) {
+  >                                                
+  >                                                        return {
+  >                                                        }
+  >                                                    }
+  >                                                }
+1->Emitted(12, 1) Source(24, 1) + SourceIndex(0)
+2 >Emitted(12, 2) Source(24, 2) + SourceIndex(0)
+3 >Emitted(12, 4) Source(14, 18) + SourceIndex(0)
+4 >Emitted(12, 11) Source(14, 25) + SourceIndex(0)
+5 >Emitted(12, 14) Source(14, 18) + SourceIndex(0)
+6 >Emitted(12, 29) Source(14, 25) + SourceIndex(0)
+7 >Emitted(12, 34) Source(14, 18) + SourceIndex(0)
+8 >Emitted(12, 49) Source(14, 25) + SourceIndex(0)
+9 >Emitted(12, 57) Source(24, 2) + SourceIndex(0)
+---
+>>>exports.createElement = Element.createElement;
+1 >
+2 >^^^^^^^^
+3 >        ^^^^^^^^^^^^^
+4 >                     ^^^
+5 >                        ^^^^^^^
+6 >                               ^
+7 >                                ^^^^^^^^^^^^^
+8 >                                             ^
+1 >
+  >
+  >export let 
+2 >
+3 >        createElement
+4 >                      = 
+5 >                        Element
+6 >                               .
+7 >                                createElement
+8 >                                             ;
+1 >Emitted(13, 1) Source(26, 12) + SourceIndex(0)
+2 >Emitted(13, 9) Source(26, 12) + SourceIndex(0)
+3 >Emitted(13, 22) Source(26, 25) + SourceIndex(0)
+4 >Emitted(13, 25) Source(26, 28) + SourceIndex(0)
+5 >Emitted(13, 32) Source(26, 35) + SourceIndex(0)
+6 >Emitted(13, 33) Source(26, 36) + SourceIndex(0)
+7 >Emitted(13, 46) Source(26, 49) + SourceIndex(0)
+8 >Emitted(13, 47) Source(26, 50) + SourceIndex(0)
+---
+>>>function toCamelCase(text) {
+1 >
+2 >^^^^^^^^^^^^^^^^^^^^^
+3 >                     ^^^^
+4 >                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >
+  >
+2 >function toCamelCase(
+3 >                     text: string
+1 >Emitted(14, 1) Source(28, 1) + SourceIndex(0)
+2 >Emitted(14, 22) Source(28, 22) + SourceIndex(0)
+3 >Emitted(14, 26) Source(28, 34) + SourceIndex(0)
+---
+>>>    return text[0].toLowerCase() + text.substring(1);
+1->^^^^
+2 >    ^^^^^^
+3 >          ^
+4 >           ^^^^
+5 >               ^
+6 >                ^
+7 >                 ^
+8 >                  ^
+9 >                   ^^^^^^^^^^^
+10>                              ^^
+11>                                ^^^
+12>                                   ^^^^
+13>                                       ^
+14>                                        ^^^^^^^^^
+15>                                                 ^
+16>                                                  ^
+17>                                                   ^
+18>                                                    ^
+1->): string {
+  >    
+2 >    return
+3 >           
+4 >           text
+5 >               [
+6 >                0
+7 >                 ]
+8 >                  .
+9 >                   toLowerCase
+10>                              ()
+11>                                 + 
+12>                                   text
+13>                                       .
+14>                                        substring
+15>                                                 (
+16>                                                  1
+17>                                                   )
+18>                                                    ;
+1->Emitted(15, 5) Source(29, 5) + SourceIndex(0)
+2 >Emitted(15, 11) Source(29, 11) + SourceIndex(0)
+3 >Emitted(15, 12) Source(29, 12) + SourceIndex(0)
+4 >Emitted(15, 16) Source(29, 16) + SourceIndex(0)
+5 >Emitted(15, 17) Source(29, 17) + SourceIndex(0)
+6 >Emitted(15, 18) Source(29, 18) + SourceIndex(0)
+7 >Emitted(15, 19) Source(29, 19) + SourceIndex(0)
+8 >Emitted(15, 20) Source(29, 20) + SourceIndex(0)
+9 >Emitted(15, 31) Source(29, 31) + SourceIndex(0)
+10>Emitted(15, 33) Source(29, 33) + SourceIndex(0)
+11>Emitted(15, 36) Source(29, 36) + SourceIndex(0)
+12>Emitted(15, 40) Source(29, 40) + SourceIndex(0)
+13>Emitted(15, 41) Source(29, 41) + SourceIndex(0)
+14>Emitted(15, 50) Source(29, 50) + SourceIndex(0)
+15>Emitted(15, 51) Source(29, 51) + SourceIndex(0)
+16>Emitted(15, 52) Source(29, 52) + SourceIndex(0)
+17>Emitted(15, 53) Source(29, 53) + SourceIndex(0)
+18>Emitted(15, 54) Source(29, 54) + SourceIndex(0)
+---
+>>>}
+1 >
+2 >^
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >
+2 >}
+1 >Emitted(16, 1) Source(30, 1) + SourceIndex(0)
+2 >Emitted(16, 2) Source(30, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=Element.js.map===================================================================
+JsFile: test.js
+mapUrl: test.js.map
+sourceRoot: 
+sources: test.tsx
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/test.js
+sourceFile:test.tsx
+-------------------------------------------------------------------
+>>>"use strict";
+>>>const Element_1 = require("./Element");
+1 >
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+3 >                                       ^^^^^^^^^^^^^^->
+1 >
+2 >import { Element} from './Element';
+1 >Emitted(2, 1) Source(1, 1) + SourceIndex(0)
+2 >Emitted(2, 40) Source(1, 36) + SourceIndex(0)
+---
+>>>let createElement = Element_1.Element.createElement;
+1->
+2 >^^^^
+3 >    ^^^^^^^^^^^^^
+4 >                 ^^^
+5 >                    ^^^^^^^^^^^^^^^^^
+6 >                                     ^
+7 >                                      ^^^^^^^^^^^^^
+8 >                                                   ^
+1->
+  >
+2 >let 
+3 >    createElement
+4 >                  = 
+5 >                    Element
+6 >                                     .
+7 >                                      createElement
+8 >                                                   ;
+1->Emitted(3, 1) Source(2, 1) + SourceIndex(0)
+2 >Emitted(3, 5) Source(2, 5) + SourceIndex(0)
+3 >Emitted(3, 18) Source(2, 18) + SourceIndex(0)
+4 >Emitted(3, 21) Source(2, 21) + SourceIndex(0)
+5 >Emitted(3, 38) Source(2, 28) + SourceIndex(0)
+6 >Emitted(3, 39) Source(2, 29) + SourceIndex(0)
+7 >Emitted(3, 52) Source(2, 42) + SourceIndex(0)
+8 >Emitted(3, 53) Source(2, 43) + SourceIndex(0)
+---
+>>>let c;
+1 >
+2 >^^^^
+3 >    ^
+4 >     ^
+5 >      ^^^^->
+1 >
+  >
+2 >let 
+3 >    c: {
+  >    	a?: {
+  >    		b: string
+  >    	}
+  >    }
+4 >     ;
+1 >Emitted(4, 1) Source(3, 1) + SourceIndex(0)
+2 >Emitted(4, 5) Source(3, 5) + SourceIndex(0)
+3 >Emitted(4, 6) Source(7, 2) + SourceIndex(0)
+4 >Emitted(4, 7) Source(7, 3) + SourceIndex(0)
+---
+>>>class A {
+1->
+2 >^^^^^^^^^^^^^->
+1->
+  >
+  >
+1->Emitted(5, 1) Source(9, 1) + SourceIndex(0)
+---
+>>>    view() {
+1->^^^^
+2 >    ^^^^
+3 >        ^^^^^^^^^->
+1->class A {
+  >	
+2 >    view
+1->Emitted(6, 5) Source(10, 2) + SourceIndex(0)
+2 >Emitted(6, 9) Source(10, 6) + SourceIndex(0)
+---
+>>>        return [
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1->() {
+  >		
+2 >        return
+3 >               
+1->Emitted(7, 9) Source(11, 3) + SourceIndex(0)
+2 >Emitted(7, 15) Source(11, 9) + SourceIndex(0)
+3 >Emitted(7, 16) Source(11, 10) + SourceIndex(0)
+---
+>>>            createElement("meta", { content: "helloworld" }),
+1->^^^^^^^^^^^^
+2 >            ^^^^^^^^^^^^^^^^^^^^^^^^
+3 >                                    ^^^^^^^
+4 >                                           ^^
+5 >                                             ^^^^^^^^^^^^
+6 >                                                         ^^^
+1->[
+  >			
+2 >            <meta 
+3 >                                    content
+4 >                                           =
+5 >                                             "helloworld"
+6 >                                                         ></meta>
+1->Emitted(8, 13) Source(12, 4) + SourceIndex(0)
+2 >Emitted(8, 37) Source(12, 10) + SourceIndex(0)
+3 >Emitted(8, 44) Source(12, 17) + SourceIndex(0)
+4 >Emitted(8, 46) Source(12, 18) + SourceIndex(0)
+5 >Emitted(8, 58) Source(12, 30) + SourceIndex(0)
+6 >Emitted(8, 61) Source(12, 38) + SourceIndex(0)
+---
+>>>            createElement("meta", { content: c.a.b })
+1 >^^^^^^^^^^^^
+2 >            ^^^^^^^^^^^^^^^^^^^^^^^^
+3 >                                    ^^^^^^^
+4 >                                           ^^
+5 >                                             ^
+6 >                                              ^
+7 >                                               ^
+8 >                                                ^
+9 >                                                 ^
+10>                                                  ^^^
+1 >,
+  >			
+2 >            <meta 
+3 >                                    content
+4 >                                           ={
+5 >                                             c
+6 >                                              .
+7 >                                               a!
+8 >                                                .
+9 >                                                 b
+10>                                                  }></meta>
+1 >Emitted(9, 13) Source(13, 4) + SourceIndex(0)
+2 >Emitted(9, 37) Source(13, 10) + SourceIndex(0)
+3 >Emitted(9, 44) Source(13, 17) + SourceIndex(0)
+4 >Emitted(9, 46) Source(13, 19) + SourceIndex(0)
+5 >Emitted(9, 47) Source(13, 20) + SourceIndex(0)
+6 >Emitted(9, 48) Source(13, 21) + SourceIndex(0)
+7 >Emitted(9, 49) Source(13, 23) + SourceIndex(0)
+8 >Emitted(9, 50) Source(13, 24) + SourceIndex(0)
+9 >Emitted(9, 51) Source(13, 25) + SourceIndex(0)
+10>Emitted(9, 54) Source(13, 34) + SourceIndex(0)
+---
+>>>        ];
+1 >^^^^^^^^^
+2 >         ^
+1 >
+  >		]
+2 >         ;
+1 >Emitted(10, 10) Source(14, 4) + SourceIndex(0)
+2 >Emitted(10, 11) Source(14, 5) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+1 >
+  >	
+2 >    }
+1 >Emitted(11, 5) Source(15, 2) + SourceIndex(0)
+2 >Emitted(11, 6) Source(15, 3) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(12, 2) Source(16, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=test.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryQualifiedName.js b/tests/baselines/reference/jsxFactoryQualifiedName.js
index e5c7b04f76056..80a77d35302c3 100644
--- a/tests/baselines/reference/jsxFactoryQualifiedName.js
+++ b/tests/baselines/reference/jsxFactoryQualifiedName.js
@@ -67,7 +67,7 @@ exports.createElement = Element.createElement;
 function toCamelCase(text) {
     return text[0].toLowerCase() + text.substring(1);
 }
-//// [test.js]
+//# sourceMappingURL=Element.js.map//// [test.js]
 "use strict";
 const Element_1 = require("./Element");
 let c;
@@ -79,3 +79,4 @@ class A {
         ];
     }
 }
+//# sourceMappingURL=test.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryQualifiedName.js.map b/tests/baselines/reference/jsxFactoryQualifiedName.js.map
new file mode 100644
index 0000000000000..f8cef24a0f0d5
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryQualifiedName.js.map
@@ -0,0 +1,3 @@
+//// [Element.js.map]
+{"version":3,"file":"Element.js","sourceRoot":"","sources":["Element.ts"],"names":[],"mappings":";AAaA,IAAiB,OAAO,CAUvB;AAVD,WAAiB,OAAO;IACpB,mBAA0B,EAAO;QAC7B,MAAM,CAAC,EAAE,CAAC,wBAAwB,KAAK,SAAS,CAAC;IACrD,CAAC;IAFe,iBAAS,YAExB,CAAA;IAED,uBAA8B,IAAW;QAErC,MAAM,CAAC,EACN,CAAA;IACL,CAAC;IAJe,qBAAa,gBAI5B,CAAA;AACL,CAAC,EAVgB,OAAO,GAAP,eAAO,KAAP,eAAO,QAUvB;AAEU,QAAA,aAAa,GAAG,OAAO,CAAC,aAAa,CAAC;AAEjD,qBAAqB,IAAY;IAC7B,MAAM,CAAC,IAAI,CAAC,CAAC,CAAC,CAAC,WAAW,EAAE,GAAG,IAAI,CAAC,SAAS,CAAC,CAAC,CAAC,CAAC;AACrD,CAAC"}//// [test.js.map]
+{"version":3,"file":"test.js","sourceRoot":"","sources":["test.tsx"],"names":[],"mappings":";AAAA,uCAAmC;AAEnC,IAAI,CAIH,CAAC;AAEF;IACC,IAAI;QACH,MAAM,CAAC;YACN,0CAAM,OAAO,EAAC,YAAY,GAAQ;YAClC,0CAAM,OAAO,EAAE,CAAC,CAAC,CAAE,CAAC,CAAC,GAAS;SAC9B,CAAC;IACH,CAAC;CACD"}
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryQualifiedName.sourcemap.txt b/tests/baselines/reference/jsxFactoryQualifiedName.sourcemap.txt
new file mode 100644
index 0000000000000..98517620c7375
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryQualifiedName.sourcemap.txt
@@ -0,0 +1,493 @@
+===================================================================
+JsFile: Element.js
+mapUrl: Element.js.map
+sourceRoot: 
+sources: Element.ts
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/Element.js
+sourceFile:Element.ts
+-------------------------------------------------------------------
+>>>"use strict";
+>>>var Element;
+1 >
+2 >^^^^
+3 >    ^^^^^^^
+4 >           ^
+5 >            ^^^^^^^^^^->
+1 >
+  >declare namespace JSX {
+  >    interface Element {
+  >        name: string;
+  >        isIntrinsic: boolean;
+  >        isCustomElement: boolean;
+  >        toString(renderId?: number): string;
+  >        bindDOM(renderId?: number): number;
+  >        resetComponent(): void;
+  >        instantiateComponents(renderId?: number): number;
+  >        props: any;
+  >    }
+  >}
+  >
+2 >export namespace 
+3 >    Element
+4 >            {
+  >               export function isElement(el: any): el is JSX.Element {
+  >                   return el.markAsChildOfRootElement !== undefined;
+  >               }
+  >           
+  >               export function createElement(args: any[]) {
+  >           
+  >                   return {
+  >                   }
+  >               }
+  >           }
+1 >Emitted(2, 1) Source(14, 1) + SourceIndex(0)
+2 >Emitted(2, 5) Source(14, 18) + SourceIndex(0)
+3 >Emitted(2, 12) Source(14, 25) + SourceIndex(0)
+4 >Emitted(2, 13) Source(24, 2) + SourceIndex(0)
+---
+>>>(function (Element) {
+1->
+2 >^^^^^^^^^^^
+3 >           ^^^^^^^
+4 >                  ^^^^^^^^^^^->
+1->
+2 >export namespace 
+3 >           Element
+1->Emitted(3, 1) Source(14, 1) + SourceIndex(0)
+2 >Emitted(3, 12) Source(14, 18) + SourceIndex(0)
+3 >Emitted(3, 19) Source(14, 25) + SourceIndex(0)
+---
+>>>    function isElement(el) {
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^
+3 >                       ^^
+4 >                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1-> {
+  >    
+2 >    export function isElement(
+3 >                       el: any
+1->Emitted(4, 5) Source(15, 5) + SourceIndex(0)
+2 >Emitted(4, 24) Source(15, 31) + SourceIndex(0)
+3 >Emitted(4, 26) Source(15, 38) + SourceIndex(0)
+---
+>>>        return el.markAsChildOfRootElement !== undefined;
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^
+5 >                 ^
+6 >                  ^^^^^^^^^^^^^^^^^^^^^^^^
+7 >                                          ^^^^^
+8 >                                               ^^^^^^^^^
+9 >                                                        ^
+1->): el is JSX.Element {
+  >        
+2 >        return
+3 >               
+4 >               el
+5 >                 .
+6 >                  markAsChildOfRootElement
+7 >                                           !== 
+8 >                                               undefined
+9 >                                                        ;
+1->Emitted(5, 9) Source(16, 9) + SourceIndex(0)
+2 >Emitted(5, 15) Source(16, 15) + SourceIndex(0)
+3 >Emitted(5, 16) Source(16, 16) + SourceIndex(0)
+4 >Emitted(5, 18) Source(16, 18) + SourceIndex(0)
+5 >Emitted(5, 19) Source(16, 19) + SourceIndex(0)
+6 >Emitted(5, 43) Source(16, 43) + SourceIndex(0)
+7 >Emitted(5, 48) Source(16, 48) + SourceIndex(0)
+8 >Emitted(5, 57) Source(16, 57) + SourceIndex(0)
+9 >Emitted(5, 58) Source(16, 58) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+3 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >    
+2 >    }
+1 >Emitted(6, 5) Source(17, 5) + SourceIndex(0)
+2 >Emitted(6, 6) Source(17, 6) + SourceIndex(0)
+---
+>>>    Element.isElement = isElement;
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^
+3 >                     ^^^^^^^^^^^^
+4 >                                 ^
+5 >                                  ^->
+1->
+2 >    isElement
+3 >                     (el: any): el is JSX.Element {
+  >                             return el.markAsChildOfRootElement !== undefined;
+  >                         }
+4 >                                 
+1->Emitted(7, 5) Source(15, 21) + SourceIndex(0)
+2 >Emitted(7, 22) Source(15, 30) + SourceIndex(0)
+3 >Emitted(7, 34) Source(17, 6) + SourceIndex(0)
+4 >Emitted(7, 35) Source(17, 6) + SourceIndex(0)
+---
+>>>    function createElement(args) {
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^^^^^
+3 >                           ^^^^
+1->
+  >
+  >    
+2 >    export function createElement(
+3 >                           args: any[]
+1->Emitted(8, 5) Source(19, 5) + SourceIndex(0)
+2 >Emitted(8, 28) Source(19, 35) + SourceIndex(0)
+3 >Emitted(8, 32) Source(19, 46) + SourceIndex(0)
+---
+>>>        return {};
+1 >^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^
+5 >                 ^
+1 >) {
+  >
+  >        
+2 >        return
+3 >               
+4 >               {
+  >                       }
+5 >                 
+1 >Emitted(9, 9) Source(21, 9) + SourceIndex(0)
+2 >Emitted(9, 15) Source(21, 15) + SourceIndex(0)
+3 >Emitted(9, 16) Source(21, 16) + SourceIndex(0)
+4 >Emitted(9, 18) Source(22, 10) + SourceIndex(0)
+5 >Emitted(9, 19) Source(22, 10) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+3 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >    
+2 >    }
+1 >Emitted(10, 5) Source(23, 5) + SourceIndex(0)
+2 >Emitted(10, 6) Source(23, 6) + SourceIndex(0)
+---
+>>>    Element.createElement = createElement;
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^^^
+3 >                         ^^^^^^^^^^^^^^^^
+4 >                                         ^
+5 >                                          ^^^^^^^^^^^^^^^->
+1->
+2 >    createElement
+3 >                         (args: any[]) {
+  >                         
+  >                                 return {
+  >                                 }
+  >                             }
+4 >                                         
+1->Emitted(11, 5) Source(19, 21) + SourceIndex(0)
+2 >Emitted(11, 26) Source(19, 34) + SourceIndex(0)
+3 >Emitted(11, 42) Source(23, 6) + SourceIndex(0)
+4 >Emitted(11, 43) Source(23, 6) + SourceIndex(0)
+---
+>>>})(Element = exports.Element || (exports.Element = {}));
+1->
+2 >^
+3 > ^^
+4 >   ^^^^^^^
+5 >          ^^^
+6 >             ^^^^^^^^^^^^^^^
+7 >                            ^^^^^
+8 >                                 ^^^^^^^^^^^^^^^
+9 >                                                ^^^^^^^^
+1->
+  >
+2 >}
+3 > 
+4 >   Element
+5 >          
+6 >             Element
+7 >                            
+8 >                                 Element
+9 >                                                 {
+  >                                                    export function isElement(el: any): el is JSX.Element {
+  >                                                        return el.markAsChildOfRootElement !== undefined;
+  >                                                    }
+  >                                                
+  >                                                    export function createElement(args: any[]) {
+  >                                                
+  >                                                        return {
+  >                                                        }
+  >                                                    }
+  >                                                }
+1->Emitted(12, 1) Source(24, 1) + SourceIndex(0)
+2 >Emitted(12, 2) Source(24, 2) + SourceIndex(0)
+3 >Emitted(12, 4) Source(14, 18) + SourceIndex(0)
+4 >Emitted(12, 11) Source(14, 25) + SourceIndex(0)
+5 >Emitted(12, 14) Source(14, 18) + SourceIndex(0)
+6 >Emitted(12, 29) Source(14, 25) + SourceIndex(0)
+7 >Emitted(12, 34) Source(14, 18) + SourceIndex(0)
+8 >Emitted(12, 49) Source(14, 25) + SourceIndex(0)
+9 >Emitted(12, 57) Source(24, 2) + SourceIndex(0)
+---
+>>>exports.createElement = Element.createElement;
+1 >
+2 >^^^^^^^^
+3 >        ^^^^^^^^^^^^^
+4 >                     ^^^
+5 >                        ^^^^^^^
+6 >                               ^
+7 >                                ^^^^^^^^^^^^^
+8 >                                             ^
+1 >
+  >
+  >export let 
+2 >
+3 >        createElement
+4 >                      = 
+5 >                        Element
+6 >                               .
+7 >                                createElement
+8 >                                             ;
+1 >Emitted(13, 1) Source(26, 12) + SourceIndex(0)
+2 >Emitted(13, 9) Source(26, 12) + SourceIndex(0)
+3 >Emitted(13, 22) Source(26, 25) + SourceIndex(0)
+4 >Emitted(13, 25) Source(26, 28) + SourceIndex(0)
+5 >Emitted(13, 32) Source(26, 35) + SourceIndex(0)
+6 >Emitted(13, 33) Source(26, 36) + SourceIndex(0)
+7 >Emitted(13, 46) Source(26, 49) + SourceIndex(0)
+8 >Emitted(13, 47) Source(26, 50) + SourceIndex(0)
+---
+>>>function toCamelCase(text) {
+1 >
+2 >^^^^^^^^^^^^^^^^^^^^^
+3 >                     ^^^^
+4 >                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >
+  >
+2 >function toCamelCase(
+3 >                     text: string
+1 >Emitted(14, 1) Source(28, 1) + SourceIndex(0)
+2 >Emitted(14, 22) Source(28, 22) + SourceIndex(0)
+3 >Emitted(14, 26) Source(28, 34) + SourceIndex(0)
+---
+>>>    return text[0].toLowerCase() + text.substring(1);
+1->^^^^
+2 >    ^^^^^^
+3 >          ^
+4 >           ^^^^
+5 >               ^
+6 >                ^
+7 >                 ^
+8 >                  ^
+9 >                   ^^^^^^^^^^^
+10>                              ^^
+11>                                ^^^
+12>                                   ^^^^
+13>                                       ^
+14>                                        ^^^^^^^^^
+15>                                                 ^
+16>                                                  ^
+17>                                                   ^
+18>                                                    ^
+1->): string {
+  >    
+2 >    return
+3 >           
+4 >           text
+5 >               [
+6 >                0
+7 >                 ]
+8 >                  .
+9 >                   toLowerCase
+10>                              ()
+11>                                 + 
+12>                                   text
+13>                                       .
+14>                                        substring
+15>                                                 (
+16>                                                  1
+17>                                                   )
+18>                                                    ;
+1->Emitted(15, 5) Source(29, 5) + SourceIndex(0)
+2 >Emitted(15, 11) Source(29, 11) + SourceIndex(0)
+3 >Emitted(15, 12) Source(29, 12) + SourceIndex(0)
+4 >Emitted(15, 16) Source(29, 16) + SourceIndex(0)
+5 >Emitted(15, 17) Source(29, 17) + SourceIndex(0)
+6 >Emitted(15, 18) Source(29, 18) + SourceIndex(0)
+7 >Emitted(15, 19) Source(29, 19) + SourceIndex(0)
+8 >Emitted(15, 20) Source(29, 20) + SourceIndex(0)
+9 >Emitted(15, 31) Source(29, 31) + SourceIndex(0)
+10>Emitted(15, 33) Source(29, 33) + SourceIndex(0)
+11>Emitted(15, 36) Source(29, 36) + SourceIndex(0)
+12>Emitted(15, 40) Source(29, 40) + SourceIndex(0)
+13>Emitted(15, 41) Source(29, 41) + SourceIndex(0)
+14>Emitted(15, 50) Source(29, 50) + SourceIndex(0)
+15>Emitted(15, 51) Source(29, 51) + SourceIndex(0)
+16>Emitted(15, 52) Source(29, 52) + SourceIndex(0)
+17>Emitted(15, 53) Source(29, 53) + SourceIndex(0)
+18>Emitted(15, 54) Source(29, 54) + SourceIndex(0)
+---
+>>>}
+1 >
+2 >^
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >
+2 >}
+1 >Emitted(16, 1) Source(30, 1) + SourceIndex(0)
+2 >Emitted(16, 2) Source(30, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=Element.js.map===================================================================
+JsFile: test.js
+mapUrl: test.js.map
+sourceRoot: 
+sources: test.tsx
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/test.js
+sourceFile:test.tsx
+-------------------------------------------------------------------
+>>>"use strict";
+>>>const Element_1 = require("./Element");
+1 >
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+1 >
+2 >import { Element} from './Element';
+1 >Emitted(2, 1) Source(1, 1) + SourceIndex(0)
+2 >Emitted(2, 40) Source(1, 36) + SourceIndex(0)
+---
+>>>let c;
+1 >
+2 >^^^^
+3 >    ^
+4 >     ^
+5 >      ^^^^->
+1 >
+  >
+  >
+2 >let 
+3 >    c: {
+  >    	a?: {
+  >    		b: string
+  >    	}
+  >    }
+4 >     ;
+1 >Emitted(3, 1) Source(3, 1) + SourceIndex(0)
+2 >Emitted(3, 5) Source(3, 5) + SourceIndex(0)
+3 >Emitted(3, 6) Source(7, 2) + SourceIndex(0)
+4 >Emitted(3, 7) Source(7, 3) + SourceIndex(0)
+---
+>>>class A {
+1->
+2 >^^^^^^^^^^^^^->
+1->
+  >
+  >
+1->Emitted(4, 1) Source(9, 1) + SourceIndex(0)
+---
+>>>    view() {
+1->^^^^
+2 >    ^^^^
+3 >        ^^^^^^^^^->
+1->class A {
+  >	
+2 >    view
+1->Emitted(5, 5) Source(10, 2) + SourceIndex(0)
+2 >Emitted(5, 9) Source(10, 6) + SourceIndex(0)
+---
+>>>        return [
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1->() {
+  >		
+2 >        return
+3 >               
+1->Emitted(6, 9) Source(11, 3) + SourceIndex(0)
+2 >Emitted(6, 15) Source(11, 9) + SourceIndex(0)
+3 >Emitted(6, 16) Source(11, 10) + SourceIndex(0)
+---
+>>>            Element_1.Element.createElement("meta", { content: "helloworld" }),
+1->^^^^^^^^^^^^
+2 >            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+3 >                                                      ^^^^^^^
+4 >                                                             ^^
+5 >                                                               ^^^^^^^^^^^^
+6 >                                                                           ^^^
+1->[
+  >			
+2 >            <meta 
+3 >                                                      content
+4 >                                                             =
+5 >                                                               "helloworld"
+6 >                                                                           ></meta>
+1->Emitted(7, 13) Source(12, 4) + SourceIndex(0)
+2 >Emitted(7, 55) Source(12, 10) + SourceIndex(0)
+3 >Emitted(7, 62) Source(12, 17) + SourceIndex(0)
+4 >Emitted(7, 64) Source(12, 18) + SourceIndex(0)
+5 >Emitted(7, 76) Source(12, 30) + SourceIndex(0)
+6 >Emitted(7, 79) Source(12, 38) + SourceIndex(0)
+---
+>>>            Element_1.Element.createElement("meta", { content: c.a.b })
+1 >^^^^^^^^^^^^
+2 >            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+3 >                                                      ^^^^^^^
+4 >                                                             ^^
+5 >                                                               ^
+6 >                                                                ^
+7 >                                                                 ^
+8 >                                                                  ^
+9 >                                                                   ^
+10>                                                                    ^^^
+1 >,
+  >			
+2 >            <meta 
+3 >                                                      content
+4 >                                                             ={
+5 >                                                               c
+6 >                                                                .
+7 >                                                                 a!
+8 >                                                                  .
+9 >                                                                   b
+10>                                                                    }></meta>
+1 >Emitted(8, 13) Source(13, 4) + SourceIndex(0)
+2 >Emitted(8, 55) Source(13, 10) + SourceIndex(0)
+3 >Emitted(8, 62) Source(13, 17) + SourceIndex(0)
+4 >Emitted(8, 64) Source(13, 19) + SourceIndex(0)
+5 >Emitted(8, 65) Source(13, 20) + SourceIndex(0)
+6 >Emitted(8, 66) Source(13, 21) + SourceIndex(0)
+7 >Emitted(8, 67) Source(13, 23) + SourceIndex(0)
+8 >Emitted(8, 68) Source(13, 24) + SourceIndex(0)
+9 >Emitted(8, 69) Source(13, 25) + SourceIndex(0)
+10>Emitted(8, 72) Source(13, 34) + SourceIndex(0)
+---
+>>>        ];
+1 >^^^^^^^^^
+2 >         ^
+1 >
+  >		]
+2 >         ;
+1 >Emitted(9, 10) Source(14, 4) + SourceIndex(0)
+2 >Emitted(9, 11) Source(14, 5) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+1 >
+  >	
+2 >    }
+1 >Emitted(10, 5) Source(15, 2) + SourceIndex(0)
+2 >Emitted(10, 6) Source(15, 3) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(11, 2) Source(16, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=test.js.map
\ No newline at end of file
diff --git a/tests/cases/compiler/jsxFactoryIdentifier.ts b/tests/cases/compiler/jsxFactoryIdentifier.ts
index 9531abeeebfaa..88caf27482e6a 100644
--- a/tests/cases/compiler/jsxFactoryIdentifier.ts
+++ b/tests/cases/compiler/jsxFactoryIdentifier.ts
@@ -2,6 +2,7 @@
 //@target: es6
 //@module: commonjs
 //@jsxFactory: createElement
+//@sourcemap: true
 
 // @filename: Element.ts
 declare namespace JSX {
diff --git a/tests/cases/compiler/jsxFactoryQualifiedName.ts b/tests/cases/compiler/jsxFactoryQualifiedName.ts
index c8d9317138b35..769b7cd566d78 100644
--- a/tests/cases/compiler/jsxFactoryQualifiedName.ts
+++ b/tests/cases/compiler/jsxFactoryQualifiedName.ts
@@ -2,6 +2,7 @@
 //@target: es6
 //@module: commonjs
 //@jsxFactory: Element.createElement
+//@sourcemap: true
 
 // @filename: Element.ts
 declare namespace JSX {

From a88c2ae1e4ef79a3f076c0f7c3fcb3aabc1f1cb3 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Wed, 9 Nov 2016 13:15:13 -0800
Subject: [PATCH 214/224] Add test cases for when jsxFactory cannot be resolved

---
 .../jsxFactoryIdentifierAsParameter.js        | 24 +++++
 .../jsxFactoryIdentifierAsParameter.js.map    |  2 +
 ...FactoryIdentifierAsParameter.sourcemap.txt | 87 +++++++++++++++++++
 .../jsxFactoryIdentifierAsParameter.symbols   | 25 ++++++
 .../jsxFactoryIdentifierAsParameter.types     | 26 ++++++
 ...ryIdentifierWithAbsentParameter.errors.txt | 19 ++++
 ...jsxFactoryIdentifierWithAbsentParameter.js | 24 +++++
 ...actoryIdentifierWithAbsentParameter.js.map |  2 +
 ...dentifierWithAbsentParameter.sourcemap.txt | 81 +++++++++++++++++
 ...oryQualifiedNameResolutionError.errors.txt | 18 ++++
 .../jsxFactoryQualifiedNameResolutionError.js | 23 +++++
 ...FactoryQualifiedNameResolutionError.js.map |  2 +
 ...QualifiedNameResolutionError.sourcemap.txt | 87 +++++++++++++++++++
 .../jsxFactoryIdentifierAsParameter.ts        | 18 ++++
 ...jsxFactoryIdentifierWithAbsentParameter.ts | 18 ++++
 .../jsxFactoryQualifiedNameResolutionError.ts | 18 ++++
 16 files changed, 474 insertions(+)
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifierAsParameter.js
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifierAsParameter.js.map
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifierAsParameter.sourcemap.txt
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifierAsParameter.symbols
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifierAsParameter.types
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.errors.txt
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.js
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.js.map
 create mode 100644 tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.sourcemap.txt
 create mode 100644 tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.errors.txt
 create mode 100644 tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.js
 create mode 100644 tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.js.map
 create mode 100644 tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.sourcemap.txt
 create mode 100644 tests/cases/compiler/jsxFactoryIdentifierAsParameter.ts
 create mode 100644 tests/cases/compiler/jsxFactoryIdentifierWithAbsentParameter.ts
 create mode 100644 tests/cases/compiler/jsxFactoryQualifiedNameResolutionError.ts

diff --git a/tests/baselines/reference/jsxFactoryIdentifierAsParameter.js b/tests/baselines/reference/jsxFactoryIdentifierAsParameter.js
new file mode 100644
index 0000000000000..ffec40ff7b654
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifierAsParameter.js
@@ -0,0 +1,24 @@
+//// [test.tsx]
+
+declare module JSX {
+    interface IntrinsicElements {
+        [s: string]: any;
+    }
+}
+
+export class AppComponent {
+    render(createElement) {
+        return <div />;
+    }
+}
+
+
+//// [test.js]
+"use strict";
+class AppComponent {
+    render(createElement) {
+        return createElement("div", null);
+    }
+}
+exports.AppComponent = AppComponent;
+//# sourceMappingURL=test.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryIdentifierAsParameter.js.map b/tests/baselines/reference/jsxFactoryIdentifierAsParameter.js.map
new file mode 100644
index 0000000000000..c108b93a9134f
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifierAsParameter.js.map
@@ -0,0 +1,2 @@
+//// [test.js.map]
+{"version":3,"file":"test.js","sourceRoot":"","sources":["test.tsx"],"names":[],"mappings":";AAOA;IACI,MAAM,CAAC,aAAa;QAChB,MAAM,CAAC,0BAAO,CAAC;IACnB,CAAC;CACJ;AAJD,oCAIC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryIdentifierAsParameter.sourcemap.txt b/tests/baselines/reference/jsxFactoryIdentifierAsParameter.sourcemap.txt
new file mode 100644
index 0000000000000..c7867fc54e09d
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifierAsParameter.sourcemap.txt
@@ -0,0 +1,87 @@
+===================================================================
+JsFile: test.js
+mapUrl: test.js.map
+sourceRoot: 
+sources: test.tsx
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/test.js
+sourceFile:test.tsx
+-------------------------------------------------------------------
+>>>"use strict";
+>>>class AppComponent {
+1 >
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >declare module JSX {
+  >    interface IntrinsicElements {
+  >        [s: string]: any;
+  >    }
+  >}
+  >
+  >
+1 >Emitted(2, 1) Source(8, 1) + SourceIndex(0)
+---
+>>>    render(createElement) {
+1->^^^^
+2 >    ^^^^^^
+3 >          ^
+4 >           ^^^^^^^^^^^^^
+5 >                        ^^^^^^^^^^^^^^^^^^^->
+1->export class AppComponent {
+  >    
+2 >    render
+3 >          (
+4 >           createElement
+1->Emitted(3, 5) Source(9, 5) + SourceIndex(0)
+2 >Emitted(3, 11) Source(9, 11) + SourceIndex(0)
+3 >Emitted(3, 12) Source(9, 12) + SourceIndex(0)
+4 >Emitted(3, 25) Source(9, 25) + SourceIndex(0)
+---
+>>>        return createElement("div", null);
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^^^^^^^^^^^^^^^^^^^^^^^^^
+5 >                                         ^
+1->) {
+  >        
+2 >        return
+3 >               
+4 >               <div />
+5 >                                         ;
+1->Emitted(4, 9) Source(10, 9) + SourceIndex(0)
+2 >Emitted(4, 15) Source(10, 15) + SourceIndex(0)
+3 >Emitted(4, 16) Source(10, 16) + SourceIndex(0)
+4 >Emitted(4, 42) Source(10, 23) + SourceIndex(0)
+5 >Emitted(4, 43) Source(10, 24) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+1 >
+  >    
+2 >    }
+1 >Emitted(5, 5) Source(11, 5) + SourceIndex(0)
+2 >Emitted(5, 6) Source(11, 6) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(6, 2) Source(12, 2) + SourceIndex(0)
+---
+>>>exports.AppComponent = AppComponent;
+1->
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+1->
+2 >export class AppComponent {
+  >    render(createElement) {
+  >        return <div />;
+  >    }
+  >}
+1->Emitted(7, 1) Source(8, 1) + SourceIndex(0)
+2 >Emitted(7, 37) Source(12, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=test.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryIdentifierAsParameter.symbols b/tests/baselines/reference/jsxFactoryIdentifierAsParameter.symbols
new file mode 100644
index 0000000000000..865292092a56c
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifierAsParameter.symbols
@@ -0,0 +1,25 @@
+=== tests/cases/compiler/test.tsx ===
+
+declare module JSX {
+>JSX : Symbol(JSX, Decl(test.tsx, 0, 0))
+
+    interface IntrinsicElements {
+>IntrinsicElements : Symbol(IntrinsicElements, Decl(test.tsx, 1, 20))
+
+        [s: string]: any;
+>s : Symbol(s, Decl(test.tsx, 3, 9))
+    }
+}
+
+export class AppComponent {
+>AppComponent : Symbol(AppComponent, Decl(test.tsx, 5, 1))
+
+    render(createElement) {
+>render : Symbol(AppComponent.render, Decl(test.tsx, 7, 27))
+>createElement : Symbol(createElement, Decl(test.tsx, 8, 11))
+
+        return <div />;
+>div : Symbol(unknown)
+    }
+}
+
diff --git a/tests/baselines/reference/jsxFactoryIdentifierAsParameter.types b/tests/baselines/reference/jsxFactoryIdentifierAsParameter.types
new file mode 100644
index 0000000000000..d55737d98aed5
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifierAsParameter.types
@@ -0,0 +1,26 @@
+=== tests/cases/compiler/test.tsx ===
+
+declare module JSX {
+>JSX : any
+
+    interface IntrinsicElements {
+>IntrinsicElements : IntrinsicElements
+
+        [s: string]: any;
+>s : string
+    }
+}
+
+export class AppComponent {
+>AppComponent : AppComponent
+
+    render(createElement) {
+>render : (createElement: any) => any
+>createElement : any
+
+        return <div />;
+><div /> : any
+>div : any
+    }
+}
+
diff --git a/tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.errors.txt b/tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.errors.txt
new file mode 100644
index 0000000000000..99e039a045fbc
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.errors.txt
@@ -0,0 +1,19 @@
+tests/cases/compiler/test.tsx(10,17): error TS2304: Cannot find name 'createElement'.
+
+
+==== tests/cases/compiler/test.tsx (1 errors) ====
+    
+    declare module JSX {
+        interface IntrinsicElements {
+            [s: string]: any;
+        }
+    }
+    
+    export class AppComponent {
+        render() {
+            return <div />;
+                    ~~~
+!!! error TS2304: Cannot find name 'createElement'.
+        }
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.js b/tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.js
new file mode 100644
index 0000000000000..23f6f44e0c7a2
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.js
@@ -0,0 +1,24 @@
+//// [test.tsx]
+
+declare module JSX {
+    interface IntrinsicElements {
+        [s: string]: any;
+    }
+}
+
+export class AppComponent {
+    render() {
+        return <div />;
+    }
+}
+
+
+//// [test.js]
+"use strict";
+class AppComponent {
+    render() {
+        return createElement("div", null);
+    }
+}
+exports.AppComponent = AppComponent;
+//# sourceMappingURL=test.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.js.map b/tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.js.map
new file mode 100644
index 0000000000000..715014ff53fbe
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.js.map
@@ -0,0 +1,2 @@
+//// [test.js.map]
+{"version":3,"file":"test.js","sourceRoot":"","sources":["test.tsx"],"names":[],"mappings":";AAOA;IACI,MAAM;QACF,MAAM,CAAC,0BAAO,CAAC;IACnB,CAAC;CACJ;AAJD,oCAIC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.sourcemap.txt b/tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.sourcemap.txt
new file mode 100644
index 0000000000000..f1ebaf49870bd
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.sourcemap.txt
@@ -0,0 +1,81 @@
+===================================================================
+JsFile: test.js
+mapUrl: test.js.map
+sourceRoot: 
+sources: test.tsx
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/test.js
+sourceFile:test.tsx
+-------------------------------------------------------------------
+>>>"use strict";
+>>>class AppComponent {
+1 >
+2 >^^^^^^^^^^^^^^^->
+1 >
+  >declare module JSX {
+  >    interface IntrinsicElements {
+  >        [s: string]: any;
+  >    }
+  >}
+  >
+  >
+1 >Emitted(2, 1) Source(8, 1) + SourceIndex(0)
+---
+>>>    render() {
+1->^^^^
+2 >    ^^^^^^
+3 >          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1->export class AppComponent {
+  >    
+2 >    render
+1->Emitted(3, 5) Source(9, 5) + SourceIndex(0)
+2 >Emitted(3, 11) Source(9, 11) + SourceIndex(0)
+---
+>>>        return createElement("div", null);
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^^^^^^^^^^^^^^^^^^^^^^^^^
+5 >                                         ^
+1->() {
+  >        
+2 >        return
+3 >               
+4 >               <div />
+5 >                                         ;
+1->Emitted(4, 9) Source(10, 9) + SourceIndex(0)
+2 >Emitted(4, 15) Source(10, 15) + SourceIndex(0)
+3 >Emitted(4, 16) Source(10, 16) + SourceIndex(0)
+4 >Emitted(4, 42) Source(10, 23) + SourceIndex(0)
+5 >Emitted(4, 43) Source(10, 24) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+1 >
+  >    
+2 >    }
+1 >Emitted(5, 5) Source(11, 5) + SourceIndex(0)
+2 >Emitted(5, 6) Source(11, 6) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(6, 2) Source(12, 2) + SourceIndex(0)
+---
+>>>exports.AppComponent = AppComponent;
+1->
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+1->
+2 >export class AppComponent {
+  >    render() {
+  >        return <div />;
+  >    }
+  >}
+1->Emitted(7, 1) Source(8, 1) + SourceIndex(0)
+2 >Emitted(7, 37) Source(12, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=test.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.errors.txt b/tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.errors.txt
new file mode 100644
index 0000000000000..97a05d840f009
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.errors.txt
@@ -0,0 +1,18 @@
+tests/cases/compiler/test.tsx(10,17): error TS2304: Cannot find name 'MyElement'.
+
+
+==== tests/cases/compiler/test.tsx (1 errors) ====
+    
+    declare module JSX {
+        interface IntrinsicElements {
+            [s: string]: any;
+        }
+    }
+    
+    export class AppComponent {
+        render(createElement) {
+            return <div />;
+                    ~~~
+!!! error TS2304: Cannot find name 'MyElement'.
+        }
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.js b/tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.js
new file mode 100644
index 0000000000000..6714b68a09397
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.js
@@ -0,0 +1,23 @@
+//// [test.tsx]
+
+declare module JSX {
+    interface IntrinsicElements {
+        [s: string]: any;
+    }
+}
+
+export class AppComponent {
+    render(createElement) {
+        return <div />;
+    }
+}
+
+//// [test.js]
+"use strict";
+class AppComponent {
+    render(createElement) {
+        return MyElement.createElement("div", null);
+    }
+}
+exports.AppComponent = AppComponent;
+//# sourceMappingURL=test.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.js.map b/tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.js.map
new file mode 100644
index 0000000000000..ac54c9638cd1b
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.js.map
@@ -0,0 +1,2 @@
+//// [test.js.map]
+{"version":3,"file":"test.js","sourceRoot":"","sources":["test.tsx"],"names":[],"mappings":";AAOA;IACI,MAAM,CAAC,aAAa;QAChB,MAAM,CAAC,oCAAO,CAAC;IACnB,CAAC;CACJ;AAJD,oCAIC"}
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.sourcemap.txt b/tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.sourcemap.txt
new file mode 100644
index 0000000000000..2616efcf63bf0
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.sourcemap.txt
@@ -0,0 +1,87 @@
+===================================================================
+JsFile: test.js
+mapUrl: test.js.map
+sourceRoot: 
+sources: test.tsx
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/test.js
+sourceFile:test.tsx
+-------------------------------------------------------------------
+>>>"use strict";
+>>>class AppComponent {
+1 >
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >declare module JSX {
+  >    interface IntrinsicElements {
+  >        [s: string]: any;
+  >    }
+  >}
+  >
+  >
+1 >Emitted(2, 1) Source(8, 1) + SourceIndex(0)
+---
+>>>    render(createElement) {
+1->^^^^
+2 >    ^^^^^^
+3 >          ^
+4 >           ^^^^^^^^^^^^^
+5 >                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1->export class AppComponent {
+  >    
+2 >    render
+3 >          (
+4 >           createElement
+1->Emitted(3, 5) Source(9, 5) + SourceIndex(0)
+2 >Emitted(3, 11) Source(9, 11) + SourceIndex(0)
+3 >Emitted(3, 12) Source(9, 12) + SourceIndex(0)
+4 >Emitted(3, 25) Source(9, 25) + SourceIndex(0)
+---
+>>>        return MyElement.createElement("div", null);
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+5 >                                                   ^
+1->) {
+  >        
+2 >        return
+3 >               
+4 >               <div />
+5 >                                                   ;
+1->Emitted(4, 9) Source(10, 9) + SourceIndex(0)
+2 >Emitted(4, 15) Source(10, 15) + SourceIndex(0)
+3 >Emitted(4, 16) Source(10, 16) + SourceIndex(0)
+4 >Emitted(4, 52) Source(10, 23) + SourceIndex(0)
+5 >Emitted(4, 53) Source(10, 24) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+1 >
+  >    
+2 >    }
+1 >Emitted(5, 5) Source(11, 5) + SourceIndex(0)
+2 >Emitted(5, 6) Source(11, 6) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(6, 2) Source(12, 2) + SourceIndex(0)
+---
+>>>exports.AppComponent = AppComponent;
+1->
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+1->
+2 >export class AppComponent {
+  >    render(createElement) {
+  >        return <div />;
+  >    }
+  >}
+1->Emitted(7, 1) Source(8, 1) + SourceIndex(0)
+2 >Emitted(7, 37) Source(12, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=test.js.map
\ No newline at end of file
diff --git a/tests/cases/compiler/jsxFactoryIdentifierAsParameter.ts b/tests/cases/compiler/jsxFactoryIdentifierAsParameter.ts
new file mode 100644
index 0000000000000..bd92a47342843
--- /dev/null
+++ b/tests/cases/compiler/jsxFactoryIdentifierAsParameter.ts
@@ -0,0 +1,18 @@
+//@jsx: react
+//@target: es6
+//@module: commonjs
+//@jsxFactory: createElement
+//@sourcemap: true
+
+// @filename: test.tsx
+declare module JSX {
+    interface IntrinsicElements {
+        [s: string]: any;
+    }
+}
+
+export class AppComponent {
+    render(createElement) {
+        return <div />;
+    }
+}
diff --git a/tests/cases/compiler/jsxFactoryIdentifierWithAbsentParameter.ts b/tests/cases/compiler/jsxFactoryIdentifierWithAbsentParameter.ts
new file mode 100644
index 0000000000000..49e485a1085f6
--- /dev/null
+++ b/tests/cases/compiler/jsxFactoryIdentifierWithAbsentParameter.ts
@@ -0,0 +1,18 @@
+//@jsx: react
+//@target: es6
+//@module: commonjs
+//@jsxFactory: createElement
+//@sourcemap: true
+
+// @filename: test.tsx
+declare module JSX {
+    interface IntrinsicElements {
+        [s: string]: any;
+    }
+}
+
+export class AppComponent {
+    render() {
+        return <div />;
+    }
+}
diff --git a/tests/cases/compiler/jsxFactoryQualifiedNameResolutionError.ts b/tests/cases/compiler/jsxFactoryQualifiedNameResolutionError.ts
new file mode 100644
index 0000000000000..a899624513851
--- /dev/null
+++ b/tests/cases/compiler/jsxFactoryQualifiedNameResolutionError.ts
@@ -0,0 +1,18 @@
+//@jsx: react
+//@target: es6
+//@module: commonjs
+//@jsxFactory: MyElement.createElement
+//@sourcemap: true
+
+// @filename: test.tsx
+declare module JSX {
+    interface IntrinsicElements {
+        [s: string]: any;
+    }
+}
+
+export class AppComponent {
+    render(createElement) {
+        return <div />;
+    }
+}
\ No newline at end of file

From dd7f00f20b4d34e8a374023a3286f05228ee295f Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Thu, 10 Nov 2016 08:53:32 -0800
Subject: [PATCH 215/224] Parse the jsxFactory again in the checker instead of
 using cached value in the program

---
 src/compiler/checker.ts          | 11 +++++++----
 src/compiler/program.ts          | 10 ++--------
 src/compiler/transformers/jsx.ts |  2 +-
 src/compiler/types.ts            |  3 +--
 src/compiler/utilities.ts        |  2 --
 5 files changed, 11 insertions(+), 17 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 6d5cee0362ee7..d8d214674d325 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -336,6 +336,8 @@ namespace ts {
 
         let jsxElementType: Type;
         let _jsxNamespace: string;
+        let _jsxFactoryEntity: EntityName;
+
         /** Things we lazy load from the JSX namespace */
         const jsxTypes = createMap<Type>();
         const JsxNames = {
@@ -377,9 +379,9 @@ namespace ts {
             if (_jsxNamespace === undefined) {
                 _jsxNamespace = "React";
                 if (compilerOptions.jsxFactory) {
-                    const jsxEntity = host.getJsxFactoryEntity();
-                    if (jsxEntity) {
-                        _jsxNamespace = getFirstIdentifier(jsxEntity).text;
+                    _jsxFactoryEntity = parseIsolatedEntityName(compilerOptions.jsxFactory, languageVersion);
+                    if (_jsxFactoryEntity) {
+                        _jsxNamespace = getFirstIdentifier(_jsxFactoryEntity).text;
                     }
                 }
                 else if (compilerOptions.reactNamespace) {
@@ -19613,7 +19615,8 @@ namespace ts {
                 getTypeReferenceDirectivesForEntityName,
                 getTypeReferenceDirectivesForSymbol,
                 isLiteralConstDeclaration,
-                writeLiteralConstValue
+                writeLiteralConstValue,
+                getJsxFactoryEntity: () => _jsxFactoryEntity
             };
 
             // defined here to avoid outer scope pollution
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 90448d197d00e..213e6a95ab173 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -329,9 +329,6 @@ namespace ts {
         // Map storing if there is emit blocking diagnostics for given input
         const hasEmitBlockingDiagnostics = createFileMap<boolean>(getCanonicalFileName);
 
-        // ReactNamespace and jsxFactory information
-        let jsxFactoryEntity: EntityName;
-
         let resolveModuleNamesWorker: (moduleNames: string[], containingFile: string) => ResolvedModuleFull[];
         if (host.resolveModuleNames) {
             resolveModuleNamesWorker = (moduleNames, containingFile) => host.resolveModuleNames(moduleNames, containingFile).map(resolved => {
@@ -424,8 +421,7 @@ namespace ts {
             getFileProcessingDiagnostics: () => fileProcessingDiagnostics,
             getResolvedTypeReferenceDirectives: () => resolvedTypeReferenceDirectives,
             isSourceFileFromExternalLibrary,
-            dropDiagnosticsProducingTypeChecker,
-            getJsxFactoryEntity: () => jsxFactoryEntity
+            dropDiagnosticsProducingTypeChecker
         };
 
         verifyCompilerOptions();
@@ -731,7 +727,6 @@ namespace ts {
                 writeFile: writeFileCallback || (
                     (fileName, data, writeByteOrderMark, onError, sourceFiles) => host.writeFile(fileName, data, writeByteOrderMark, onError, sourceFiles)),
                 isEmitBlocked,
-                getJsxFactoryEntity: program.getJsxFactoryEntity,
             };
         }
 
@@ -1679,8 +1674,7 @@ namespace ts {
                 if (options.reactNamespace) {
                     programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Option_0_cannot_be_specified_with_option_1, "reactNamespace", "jsxFactory"));
                 }
-                jsxFactoryEntity = parseIsolatedEntityName(options.jsxFactory, languageVersion);
-                if (!jsxFactoryEntity) {
+                if (!parseIsolatedEntityName(options.jsxFactory, languageVersion)) {
                     programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Invalid_value_for_jsxFactory_0_is_not_a_valid_identifier_or_qualified_name, options.jsxFactory));
                 }
             }
diff --git a/src/compiler/transformers/jsx.ts b/src/compiler/transformers/jsx.ts
index 874f4f6862f49..ba762cc5f12c8 100644
--- a/src/compiler/transformers/jsx.ts
+++ b/src/compiler/transformers/jsx.ts
@@ -114,7 +114,7 @@ namespace ts {
             }
 
             const element = createExpressionForJsxElement(
-                context.getEmitHost().getJsxFactoryEntity(),
+                context.getEmitResolver().getJsxFactoryEntity(),
                 compilerOptions.reactNamespace,
                 tagName,
                 objectProperties,
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 09d32ad817eb6..08e117d23e738 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2177,7 +2177,6 @@ namespace ts {
         getTypeChecker(): TypeChecker;
 
         /* @internal */ getCommonSourceDirectory(): string;
-        /* @internal */ getJsxFactoryEntity(): EntityName;
 
         // For testing purposes only.  Should not be used by any other consumers (including the
         // language service).
@@ -2251,7 +2250,6 @@ namespace ts {
     /* @internal */
     export interface TypeCheckerHost {
         getCompilerOptions(): CompilerOptions;
-        getJsxFactoryEntity(): EntityName;
 
         getSourceFiles(): SourceFile[];
         getSourceFile(fileName: string): SourceFile;
@@ -2475,6 +2473,7 @@ namespace ts {
         getTypeReferenceDirectivesForSymbol(symbol: Symbol, meaning?: SymbolFlags): string[];
         isLiteralConstDeclaration(node: VariableDeclaration | PropertyDeclaration | PropertySignature | ParameterDeclaration): boolean;
         writeLiteralConstValue(node: VariableDeclaration | PropertyDeclaration | PropertySignature | ParameterDeclaration, writer: SymbolWriter): void;
+        getJsxFactoryEntity(): EntityName;
     }
 
     export const enum SymbolFlags {
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 826beccc7b12b..299f91be6625c 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -34,8 +34,6 @@ namespace ts {
         /* @internal */
         isSourceFileFromExternalLibrary(file: SourceFile): boolean;
 
-        /* @internal */
-        getJsxFactoryEntity(): EntityName;
         getCommonSourceDirectory(): string;
         getCanonicalFileName(fileName: string): string;
         getNewLine(): string;

From c05e226c4bbf43cf0b1b8ad451b9046e349ed310 Mon Sep 17 00:00:00 2001
From: Myles Megyesi <mylesmegyesi@users.noreply.github.com>
Date: Thu, 10 Nov 2016 11:31:27 -0600
Subject: [PATCH 216/224] Adds error message for incompatible assignment of
 identically named type

Fixes issue #12050
---
 src/compiler/checker.ts                       | 12 ++++++++---
 src/compiler/diagnosticMessages.json          |  4 ++++
 ...signmentOfIdenticallyNamedTypes.errors.txt | 15 ++++++++++++++
 ...atibleAssignmentOfIdenticallyNamedTypes.js | 20 +++++++++++++++++++
 ...atibleAssignmentOfIdenticallyNamedTypes.ts |  8 ++++++++
 5 files changed, 56 insertions(+), 3 deletions(-)
 create mode 100644 tests/baselines/reference/incompatibleAssignmentOfIdenticallyNamedTypes.errors.txt
 create mode 100644 tests/baselines/reference/incompatibleAssignmentOfIdenticallyNamedTypes.js
 create mode 100644 tests/cases/compiler/incompatibleAssignmentOfIdenticallyNamedTypes.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 9128398299c6c..6dad58ebe0249 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -6824,9 +6824,15 @@ namespace ts {
                 }
 
                 if (!message) {
-                    message = relation === comparableRelation ?
-                        Diagnostics.Type_0_is_not_comparable_to_type_1 :
-                        Diagnostics.Type_0_is_not_assignable_to_type_1;
+                    if (relation === comparableRelation) {
+                        message = Diagnostics.Type_0_is_not_comparable_to_type_1;
+                    }
+                    else if (sourceType === targetType) {
+                        message = Diagnostics.Type_0_is_not_assignable_to_type_1_Two_different_types_with_this_name_exist_but_they_are_unrelated;
+                    }
+                    else {
+                        message = Diagnostics.Type_0_is_not_assignable_to_type_1;
+                    }
                 }
 
                 reportError(message, sourceType, targetType);
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 5bcc255c0a5ca..bc2ab6c3ff470 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -3170,5 +3170,9 @@
     "Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig": {
         "category": "Error",
         "code": 90009
+    },
+    "Type '{0}' is not assignable to type '{1}'. Two different types with this name exist, but they are unrelated.": {
+        "category": "Error",
+        "code": 90010
     }
 }
diff --git a/tests/baselines/reference/incompatibleAssignmentOfIdenticallyNamedTypes.errors.txt b/tests/baselines/reference/incompatibleAssignmentOfIdenticallyNamedTypes.errors.txt
new file mode 100644
index 0000000000000..3f1de47c3476d
--- /dev/null
+++ b/tests/baselines/reference/incompatibleAssignmentOfIdenticallyNamedTypes.errors.txt
@@ -0,0 +1,15 @@
+tests/cases/compiler/incompatibleAssignmentOfIdenticallyNamedTypes.ts(6,9): error TS90010: Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
+
+
+==== tests/cases/compiler/incompatibleAssignmentOfIdenticallyNamedTypes.ts (1 errors) ====
+    interface T { }
+    declare const a: T;
+    class Foo<T> {
+        x: T;
+        fn() {
+            this.x = a;
+            ~~~~~~
+!!! error TS90010: Type 'T' is not assignable to type 'T'. Two different types with this name exist, but they are unrelated.
+        }
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/incompatibleAssignmentOfIdenticallyNamedTypes.js b/tests/baselines/reference/incompatibleAssignmentOfIdenticallyNamedTypes.js
new file mode 100644
index 0000000000000..677d177a4d01a
--- /dev/null
+++ b/tests/baselines/reference/incompatibleAssignmentOfIdenticallyNamedTypes.js
@@ -0,0 +1,20 @@
+//// [incompatibleAssignmentOfIdenticallyNamedTypes.ts]
+interface T { }
+declare const a: T;
+class Foo<T> {
+    x: T;
+    fn() {
+        this.x = a;
+    }
+}
+
+
+//// [incompatibleAssignmentOfIdenticallyNamedTypes.js]
+var Foo = (function () {
+    function Foo() {
+    }
+    Foo.prototype.fn = function () {
+        this.x = a;
+    };
+    return Foo;
+}());
diff --git a/tests/cases/compiler/incompatibleAssignmentOfIdenticallyNamedTypes.ts b/tests/cases/compiler/incompatibleAssignmentOfIdenticallyNamedTypes.ts
new file mode 100644
index 0000000000000..493feef1fd724
--- /dev/null
+++ b/tests/cases/compiler/incompatibleAssignmentOfIdenticallyNamedTypes.ts
@@ -0,0 +1,8 @@
+interface T { }
+declare const a: T;
+class Foo<T> {
+    x: T;
+    fn() {
+        this.x = a;
+    }
+}

From 2eba10a25b85150075fd55348e2bd86d6271b54c Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Thu, 10 Nov 2016 08:53:32 -0800
Subject: [PATCH 217/224] Updated condition for more readability

---
 src/compiler/program.ts | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 15e08842e7617..7f614494e3b3e 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1006,11 +1006,10 @@ namespace ts {
                                 return;
                             }
                             // pass through
-                            let isConstInvalid = true;
                         case SyntaxKind.VariableStatement:
                             // Check modifiers
                             if (nodes === (<ClassDeclaration | FunctionLikeDeclaration | VariableStatement>parent).modifiers) {
-                                return checkModifiers(<NodeArray<Modifier>>nodes, !isConstInvalid);
+                                return checkModifiers(<NodeArray<Modifier>>nodes, parent.kind === SyntaxKind.VariableStatement);
                             }
                             break;
                         case SyntaxKind.PropertyDeclaration:

From 0d4ac0157466cc2b68d5e5392f9ea94ede20dede Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 10 Nov 2016 11:45:56 -0800
Subject: [PATCH 218/224] Report errors for import helpers missing __rest

---
 src/compiler/checker.ts | 6 +++++-
 src/compiler/types.ts   | 2 +-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 95faebd2875e5..e7f3558a3e62f 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -19970,9 +19970,13 @@ namespace ts {
                     if (requestedExternalEmitHelpers & NodeFlags.HasClassExtends && languageVersion < ScriptTarget.ES2015) {
                         verifyHelperSymbol(exports, "__extends", SymbolFlags.Value);
                     }
-                    if (requestedExternalEmitHelpers & NodeFlags.HasSpreadAttribute && compilerOptions.jsx !== JsxEmit.Preserve) {
+                    if (requestedExternalEmitHelpers & NodeFlags.HasSpreadAttribute &&
+                        (languageVersion < ScriptTarget.ESNext || compilerOptions.jsx === JsxEmit.React)) {
                         verifyHelperSymbol(exports, "__assign", SymbolFlags.Value);
                     }
+                    if (languageVersion < ScriptTarget.ESNext && requestedExternalEmitHelpers & NodeFlags.HasRestAttribute) {
+                        verifyHelperSymbol(exports, "__rest", SymbolFlags.Value);
+                    }
                     if (requestedExternalEmitHelpers & NodeFlags.HasDecorators) {
                         verifyHelperSymbol(exports, "__decorate", SymbolFlags.Value);
                         if (compilerOptions.emitDecoratorMetadata) {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 9889d3ad1af25..7db19af7382fb 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -433,7 +433,7 @@ namespace ts {
         BlockScoped = Let | Const,
 
         ReachabilityCheckFlags = HasImplicitReturn | HasExplicitReturn,
-        EmitHelperFlags = HasClassExtends | HasDecorators | HasParamDecorators | HasAsyncFunctions | HasSpreadAttribute,
+        EmitHelperFlags = HasClassExtends | HasDecorators | HasParamDecorators | HasAsyncFunctions | HasSpreadAttribute | HasRestAttribute,
         ReachabilityAndEmitFlags = ReachabilityCheckFlags | EmitHelperFlags,
 
         // Parsing context flags

From d6bf27d6b6bc4a74d8cd47c68f1b452171cdf3dd Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 10 Nov 2016 11:46:10 -0800
Subject: [PATCH 219/224] Correctly check spread assignments in strict mode

Previously it crashed in the binder.
---
 src/compiler/binder.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 197adfdb5c43b..3e65b547d5b82 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -1553,7 +1553,7 @@ namespace ts {
                 const seen = createMap<ElementKind>();
 
                 for (const prop of node.properties) {
-                    if (prop.name.kind !== SyntaxKind.Identifier) {
+                    if (prop.kind === SyntaxKind.SpreadAssignment || prop.name.kind !== SyntaxKind.Identifier) {
                         continue;
                     }
 

From ba6e5a0ffad18b1852a3f3a2be6804cc95d3ae15 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Thu, 10 Nov 2016 11:47:03 -0800
Subject: [PATCH 220/224] Test error for import helpers with no __rest

---
 .../reference/importHelpersNoHelpers.errors.txt       | 11 ++++++++++-
 tests/baselines/reference/importHelpersNoHelpers.js   | 10 +++++++++-
 tests/cases/compiler/importHelpersNoHelpers.ts        |  6 +++++-
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/tests/baselines/reference/importHelpersNoHelpers.errors.txt b/tests/baselines/reference/importHelpersNoHelpers.errors.txt
index ebb25dbd7c974..fa9a935c8d811 100644
--- a/tests/baselines/reference/importHelpersNoHelpers.errors.txt
+++ b/tests/baselines/reference/importHelpersNoHelpers.errors.txt
@@ -1,13 +1,17 @@
+error TS2305: Module 'tslib' has no exported member '__assign'.
 error TS2305: Module 'tslib' has no exported member '__decorate'.
 error TS2305: Module 'tslib' has no exported member '__extends'.
 error TS2305: Module 'tslib' has no exported member '__metadata'.
 error TS2305: Module 'tslib' has no exported member '__param'.
+error TS2305: Module 'tslib' has no exported member '__rest'.
 
 
+!!! error TS2305: Module 'tslib' has no exported member '__assign'.
 !!! error TS2305: Module 'tslib' has no exported member '__decorate'.
 !!! error TS2305: Module 'tslib' has no exported member '__extends'.
 !!! error TS2305: Module 'tslib' has no exported member '__metadata'.
 !!! error TS2305: Module 'tslib' has no exported member '__param'.
+!!! error TS2305: Module 'tslib' has no exported member '__rest'.
 ==== tests/cases/compiler/external.ts (0 errors) ====
     export class A { }
     export class B extends A { }
@@ -20,6 +24,10 @@ error TS2305: Module 'tslib' has no exported member '__param'.
         }
     }
     
+    const o = { a: 1 };
+    const y = { ...o };
+    const { ...x } = y;
+    
 ==== tests/cases/compiler/script.ts (0 errors) ====
     class A { }
     class B extends A { }
@@ -33,4 +41,5 @@ error TS2305: Module 'tslib' has no exported member '__param'.
     }
     
 ==== tests/cases/compiler/tslib.d.ts (0 errors) ====
-    export {}
\ No newline at end of file
+    export {}
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/importHelpersNoHelpers.js b/tests/baselines/reference/importHelpersNoHelpers.js
index e22d1f4353d71..690a6c05f17f8 100644
--- a/tests/baselines/reference/importHelpersNoHelpers.js
+++ b/tests/baselines/reference/importHelpersNoHelpers.js
@@ -11,6 +11,10 @@ class C {
     method(@dec x: number) {
     }
 }
+
+const o = { a: 1 };
+const y = { ...o };
+const { ...x } = y;
 
 //// [script.ts]
 class A { }
@@ -25,7 +29,8 @@ class C {
 }
 
 //// [tslib.d.ts]
-export {}
+export {}
+
 
 //// [external.js]
 "use strict";
@@ -61,6 +66,9 @@ C = tslib_1.__decorate([
     dec,
     tslib_1.__metadata("design:paramtypes", [])
 ], C);
+var o = { a: 1 };
+var y = __assign({}, o);
+var x = __rest(y, []);
 //// [script.js]
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
diff --git a/tests/cases/compiler/importHelpersNoHelpers.ts b/tests/cases/compiler/importHelpersNoHelpers.ts
index 8242855254806..4ab48aba7df34 100644
--- a/tests/cases/compiler/importHelpersNoHelpers.ts
+++ b/tests/cases/compiler/importHelpersNoHelpers.ts
@@ -16,6 +16,10 @@ class C {
     }
 }
 
+const o = { a: 1 };
+const y = { ...o };
+const { ...x } = y;
+
 // @filename: script.ts
 class A { }
 class B extends A { }
@@ -29,4 +33,4 @@ class C {
 }
 
 // @filename: tslib.d.ts
-export {}
\ No newline at end of file
+export {}

From 3ecb60146b5d91db14cf1467f4a9d9b0d25e9ce5 Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Thu, 10 Nov 2016 11:57:37 -0800
Subject: [PATCH 221/224] synthesize complete import declaration for tslib
 (#12151)

---
 src/compiler/program.ts                        |  9 +++++++--
 src/harness/unittests/tsserverProjectSystem.ts | 17 +++++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 5cd957708f51b..eb7054a9f06e9 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1143,9 +1143,14 @@ namespace ts {
             if (options.importHelpers
                 && (options.isolatedModules || isExternalModuleFile)
                 && !file.isDeclarationFile) {
-                const externalHelpersModuleReference = <StringLiteral>createNode(SyntaxKind.StringLiteral);
+                // synthesize 'import "tslib"' declaration
+                const externalHelpersModuleReference = <StringLiteral>createSynthesizedNode(SyntaxKind.StringLiteral);
                 externalHelpersModuleReference.text = externalHelpersModuleNameText;
-                externalHelpersModuleReference.parent = file;
+                const importDecl = createSynthesizedNode(SyntaxKind.ImportDeclaration);
+
+                importDecl.parent = file;
+                externalHelpersModuleReference.parent = importDecl;
+
                 imports = [externalHelpersModuleReference];
             }
 
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index 17b1dd3e585f7..7986137ca4344 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -2576,4 +2576,21 @@ namespace ts.projectSystem {
             assert.isTrue(diags.length === 0);
         });
     });
+
+    describe("import helpers", () => {
+        it("should not crash in tsserver", () => {
+            const f1 = {
+                path: "/a/app.ts",
+                content: "export async function foo() { return 100; }"
+            };
+            const tslib = {
+                path: "/a/node_modules/tslib/index.d.ts",
+                content: ""
+            };
+            const host = createServerHost([f1, tslib]);
+            const service = createProjectService(host);
+            service.openExternalProject({ projectFileName: "p", rootFiles: [toExternalFile(f1.path)], options: { importHelpers: true } });
+            service.checkNumberOfProjects({ externalProjects: 1 });
+        });
+    });
 }
\ No newline at end of file

From 9a8e1bf8a62936bb6acf7d2d8f16de7f466a1be4 Mon Sep 17 00:00:00 2001
From: Cotton Hou <himcotton@gmail.com>
Date: Fri, 11 Nov 2016 04:43:51 +0800
Subject: [PATCH 222/224] Add ES2017 string padding (#12152)

* add es2017.string.d.ts for String.prototype.{padStart,padEnd}

* append es2017.string.d.ts into es2017.d.ts

* add es2017.string into commandLineParser

* append es2017.string into error message for unit tests of commandLineParser

* append es2017.string into Gulpfile

* append es2017.string into Jakefile
---
 Gulpfile.ts                                   |  3 ++-
 Jakefile.js                                   |  3 ++-
 src/compiler/commandLineParser.ts             |  3 ++-
 src/harness/unittests/commandLineParsing.ts   |  6 ++---
 .../convertCompilerOptionsFromJson.ts         |  8 +++---
 src/lib/es2017.d.ts                           |  3 ++-
 src/lib/es2017.string.d.ts                    | 27 +++++++++++++++++++
 7 files changed, 42 insertions(+), 11 deletions(-)
 create mode 100644 src/lib/es2017.string.d.ts

diff --git a/Gulpfile.ts b/Gulpfile.ts
index ebedfd43c23ac..d7e20a557fd78 100644
--- a/Gulpfile.ts
+++ b/Gulpfile.ts
@@ -128,7 +128,8 @@ const es2016LibrarySourceMap = es2016LibrarySource.map(function(source) {
 
 const es2017LibrarySource = [
     "es2017.object.d.ts",
-    "es2017.sharedmemory.d.ts"
+    "es2017.sharedmemory.d.ts",
+    "es2017.string.d.ts",
 ];
 
 const es2017LibrarySourceMap = es2017LibrarySource.map(function(source) {
diff --git a/Jakefile.js b/Jakefile.js
index 0e778b44c3550..2e5d660c4f1d9 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -303,7 +303,8 @@ var es2016LibrarySourceMap = es2016LibrarySource.map(function (source) {
 
 var es2017LibrarySource = [
     "es2017.object.d.ts",
-    "es2017.sharedmemory.d.ts"
+    "es2017.sharedmemory.d.ts",
+    "es2017.string.d.ts",
 ];
 
 var es2017LibrarySourceMap = es2017LibrarySource.map(function (source) {
diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index d96035091c713..df9c3c4abddc5 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -434,7 +434,8 @@ namespace ts {
                     "es2015.symbol.wellknown": "lib.es2015.symbol.wellknown.d.ts",
                     "es2016.array.include": "lib.es2016.array.include.d.ts",
                     "es2017.object": "lib.es2017.object.d.ts",
-                    "es2017.sharedmemory": "lib.es2017.sharedmemory.d.ts"
+                    "es2017.sharedmemory": "lib.es2017.sharedmemory.d.ts",
+                    "es2017.string": "lib.es2017.string.d.ts",
                 }),
             },
             description: Diagnostics.Specify_library_files_to_be_included_in_the_compilation_Colon
diff --git a/src/harness/unittests/commandLineParsing.ts b/src/harness/unittests/commandLineParsing.ts
index 890f167e2dd2c..8c691992043db 100644
--- a/src/harness/unittests/commandLineParsing.ts
+++ b/src/harness/unittests/commandLineParsing.ts
@@ -60,7 +60,7 @@ namespace ts {
             assertParseResult(["--lib", "es5,invalidOption", "0.ts"],
                 {
                     errors: [{
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         category: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.category,
                         code: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
 
@@ -263,7 +263,7 @@ namespace ts {
             assertParseResult(["--lib", "es5,", "es7", "0.ts"],
                 {
                     errors: [{
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         category: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.category,
                         code: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
 
@@ -283,7 +283,7 @@ namespace ts {
             assertParseResult(["--lib", "es5, ", "es7", "0.ts"],
                 {
                     errors: [{
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         category: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.category,
                         code: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
 
diff --git a/src/harness/unittests/convertCompilerOptionsFromJson.ts b/src/harness/unittests/convertCompilerOptionsFromJson.ts
index 23c372b531330..f44dc259710e5 100644
--- a/src/harness/unittests/convertCompilerOptionsFromJson.ts
+++ b/src/harness/unittests/convertCompilerOptionsFromJson.ts
@@ -233,7 +233,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
@@ -264,7 +264,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
@@ -295,7 +295,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
@@ -326,7 +326,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory'",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string'",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
diff --git a/src/lib/es2017.d.ts b/src/lib/es2017.d.ts
index 13f9d93f44457..c234a9edb249f 100644
--- a/src/lib/es2017.d.ts
+++ b/src/lib/es2017.d.ts
@@ -1,3 +1,4 @@
 /// <reference path="lib.es2016.d.ts" />
 /// <reference path="lib.es2017.object.d.ts" />
-/// <reference path="lib.es2017.sharedmemory.d.ts" />
\ No newline at end of file
+/// <reference path="lib.es2017.sharedmemory.d.ts" />
+/// <reference path="lib.es2017.string.d.ts" />
diff --git a/src/lib/es2017.string.d.ts b/src/lib/es2017.string.d.ts
new file mode 100644
index 0000000000000..51f8e410ecf82
--- /dev/null
+++ b/src/lib/es2017.string.d.ts
@@ -0,0 +1,27 @@
+interface String {
+    /**
+      * Pads the current string with a given string (possibly repeated) so that the resulting string reaches a given length.
+      * The padding is applied from the start (left) of the current string.
+      *
+      * @param maxLength The length of the resulting string once the current string has been padded.
+      *        If this parameter is smaller than the current string's length, the current string will be returned as it is.
+      *
+      * @param fillString The string to pad the current string with.
+      *        If this string is too long, it will be truncated and the left-most part will be applied.
+      *        The default value for this parameter is " " (U+0020).
+      */
+    padStart(maxLength: number, fillString?: string): string;
+
+    /**
+      * Pads the current string with a given string (possibly repeated) so that the resulting string reaches a given length.
+      * The padding is applied from the end (right) of the current string.
+      *
+      * @param maxLength The length of the resulting string once the current string has been padded.
+      *        If this parameter is smaller than the current string's length, the current string will be returned as it is.
+      *
+      * @param fillString The string to pad the current string with.
+      *        If this string is too long, it will be truncated and the left-most part will be applied.
+      *        The default value for this parameter is " " (U+0020).
+      */
+    padEnd(maxLength: number, fillString?: string): string;
+}

From 4dc58dde38bd5b48003984a9b57452c228ed859d Mon Sep 17 00:00:00 2001
From: Zhengbo Li <zhengbli@microsoft.com>
Date: Thu, 10 Nov 2016 14:12:24 -0800
Subject: [PATCH 223/224] Exclude js files in non-configured projects
 compile-on-save emitting (#12118)

* Exclude js files in non-configured projects CoS emitting

* remove unnecessary method
---
 src/compiler/program.ts                | 23 ++++------
 src/compiler/types.ts                  |  2 +-
 src/compiler/utilities.ts              | 58 ++++++++++++++------------
 src/harness/unittests/compileOnSave.ts | 40 ++++++++++++++++++
 src/server/project.ts                  |  4 +-
 5 files changed, 82 insertions(+), 45 deletions(-)

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index eb7054a9f06e9..8b53f68bc6f7d 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1706,18 +1706,13 @@ namespace ts {
                     const emitFilePath = toPath(emitFileName, currentDirectory, getCanonicalFileName);
                     // Report error if the output overwrites input file
                     if (filesByName.contains(emitFilePath)) {
-                        if (options.noEmitOverwritenFiles && !options.out && !options.outDir && !options.outFile) {
-                            blockEmittingOfFile(emitFileName);
-                        }
-                        else {
-                            let chain: DiagnosticMessageChain;
-                            if (!options.configFilePath) {
-                                // The program is from either an inferred project or an external project
-                                chain = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Adding_a_tsconfig_json_file_will_help_organize_projects_that_contain_both_TypeScript_and_JavaScript_files_Learn_more_at_https_Colon_Slash_Slashaka_ms_Slashtsconfig);
-                            }
-                            chain = chainDiagnosticMessages(chain, Diagnostics.Cannot_write_file_0_because_it_would_overwrite_input_file, emitFileName);
-                            blockEmittingOfFile(emitFileName, createCompilerDiagnosticFromMessageChain(chain));
+                        let chain: DiagnosticMessageChain;
+                        if (!options.configFilePath) {
+                            // The program is from either an inferred project or an external project
+                            chain = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Adding_a_tsconfig_json_file_will_help_organize_projects_that_contain_both_TypeScript_and_JavaScript_files_Learn_more_at_https_Colon_Slash_Slashaka_ms_Slashtsconfig);
                         }
+                        chain = chainDiagnosticMessages(chain, Diagnostics.Cannot_write_file_0_because_it_would_overwrite_input_file, emitFileName);
+                        blockEmittingOfFile(emitFileName, createCompilerDiagnosticFromMessageChain(chain));
                     }
 
                     // Report error if multiple files write into same file
@@ -1732,11 +1727,9 @@ namespace ts {
             }
         }
 
-        function blockEmittingOfFile(emitFileName: string, diag?: Diagnostic) {
+        function blockEmittingOfFile(emitFileName: string, diag: Diagnostic) {
             hasEmitBlockingDiagnostics.set(toPath(emitFileName, currentDirectory, getCanonicalFileName), true);
-            if (diag) {
-                programDiagnostics.add(diag);
-            }
+            programDiagnostics.add(diag);
         }
     }
 
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 7db19af7382fb..c814a2b1d463d 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -3075,7 +3075,7 @@ namespace ts {
         moduleResolution?: ModuleResolutionKind;
         newLine?: NewLineKind;
         noEmit?: boolean;
-        /*@internal*/noEmitOverwritenFiles?: boolean;
+        /*@internal*/noEmitForJsFiles?: boolean;
         noEmitHelpers?: boolean;
         noEmitOnError?: boolean;
         noErrorTruncation?: boolean;
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 667612d7771c0..c49c33b857f84 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -192,7 +192,7 @@ namespace ts {
     export function nodePosToString(node: Node): string {
         const file = getSourceFileOfNode(node);
         const loc = getLineAndCharacterOfPosition(file, node.pos);
-        return `${ file.fileName }(${ loc.line + 1 },${ loc.character + 1 })`;
+        return `${file.fileName}(${loc.line + 1},${loc.character + 1})`;
     }
 
     export function getStartPosOfNode(node: Node): number {
@@ -439,7 +439,7 @@ namespace ts {
     }
 
     export function isBlockScope(node: Node, parentNode: Node) {
-        switch (node.kind)  {
+        switch (node.kind) {
             case SyntaxKind.SourceFile:
             case SyntaxKind.CaseBlock:
             case SyntaxKind.CatchClause:
@@ -644,9 +644,9 @@ namespace ts {
 
     export function getJsDocCommentsFromText(node: Node, text: string) {
         const commentRanges = (node.kind === SyntaxKind.Parameter ||
-                               node.kind === SyntaxKind.TypeParameter ||
-                               node.kind === SyntaxKind.FunctionExpression ||
-                               node.kind === SyntaxKind.ArrowFunction) ?
+            node.kind === SyntaxKind.TypeParameter ||
+            node.kind === SyntaxKind.FunctionExpression ||
+            node.kind === SyntaxKind.ArrowFunction) ?
             concatenate(getTrailingCommentRanges(text, node.pos), getLeadingCommentRanges(text, node.pos)) :
             getLeadingCommentRangesOfNodeFromText(node, text);
         return filter(commentRanges, isJsDocComment);
@@ -911,7 +911,7 @@ namespace ts {
     export function isObjectLiteralOrClassExpressionMethod(node: Node): node is MethodDeclaration {
         return node.kind === SyntaxKind.MethodDeclaration &&
             (node.parent.kind === SyntaxKind.ObjectLiteralExpression ||
-            node.parent.kind === SyntaxKind.ClassExpression);
+                node.parent.kind === SyntaxKind.ClassExpression);
     }
 
     export function isIdentifierTypePredicate(predicate: TypePredicate): predicate is IdentifierTypePredicate {
@@ -1133,8 +1133,8 @@ namespace ts {
                 // if the parameter's parent has a body and its grandparent is a class declaration, this is a valid target;
                 return (<FunctionLikeDeclaration>node.parent).body !== undefined
                     && (node.parent.kind === SyntaxKind.Constructor
-                    || node.parent.kind === SyntaxKind.MethodDeclaration
-                    || node.parent.kind === SyntaxKind.SetAccessor)
+                        || node.parent.kind === SyntaxKind.MethodDeclaration
+                        || node.parent.kind === SyntaxKind.SetAccessor)
                     && node.parent.parent.kind === SyntaxKind.ClassDeclaration;
         }
 
@@ -1481,7 +1481,7 @@ namespace ts {
         }, tags => tags);
     }
 
-   function getJSDocs<T>(node: Node, checkParentVariableStatement: boolean, getDocs: (docs: JSDoc[]) => T[], getTags: (tags: JSDocTag[]) => T[]): T[] {
+    function getJSDocs<T>(node: Node, checkParentVariableStatement: boolean, getDocs: (docs: JSDoc[]) => T[], getTags: (tags: JSDocTag[]) => T[]): T[] {
         // TODO: Get rid of getJsDocComments and friends (note the lowercase 's' in Js)
         // TODO: A lot of this work should be cached, maybe. I guess it's only used in services right now...
         let result: T[] = undefined;
@@ -1502,8 +1502,8 @@ namespace ts {
 
             const variableStatementNode =
                 isInitializerOfVariableDeclarationInStatement ? node.parent.parent.parent :
-                isVariableOfVariableDeclarationStatement ? node.parent.parent :
-                undefined;
+                    isVariableOfVariableDeclarationStatement ? node.parent.parent :
+                        undefined;
             if (variableStatementNode) {
                 result = append(result, getJSDocs(variableStatementNode, checkParentVariableStatement, getDocs, getTags));
             }
@@ -1668,7 +1668,7 @@ namespace ts {
                     if ((<ShorthandPropertyAssignment>parent).name !== node) {
                         return AssignmentKind.None;
                     }
-                    // Fall through
+                // Fall through
                 case SyntaxKind.PropertyAssignment:
                     node = parent.parent;
                     break;
@@ -2570,14 +2570,18 @@ namespace ts {
         if (options.outFile || options.out) {
             const moduleKind = getEmitModuleKind(options);
             const moduleEmitEnabled = moduleKind === ModuleKind.AMD || moduleKind === ModuleKind.System;
-            const sourceFiles = host.getSourceFiles();
+            const sourceFiles = getAllEmittableSourceFiles();
             // Can emit only sources that are not declaration file and are either non module code or module with --module or --target es6 specified
             return filter(sourceFiles, moduleEmitEnabled ? isNonDeclarationFile : isBundleEmitNonExternalModule);
         }
         else {
-            const sourceFiles = targetSourceFile === undefined ? host.getSourceFiles() : [targetSourceFile];
+            const sourceFiles = targetSourceFile === undefined ? getAllEmittableSourceFiles() : [targetSourceFile];
             return filter(sourceFiles, isNonDeclarationFile);
         }
+
+        function getAllEmittableSourceFiles() {
+            return options.noEmitForJsFiles ? filter(host.getSourceFiles(), sourceFile => !isSourceFileJavaScript(sourceFile)) : host.getSourceFiles();
+        }
     }
 
     function isNonDeclarationFile(sourceFile: SourceFile) {
@@ -2609,7 +2613,7 @@ namespace ts {
         }
         else {
             for (const sourceFile of sourceFiles) {
-                 // Don't emit if source file is a declaration file, or was located under node_modules
+                // Don't emit if source file is a declaration file, or was located under node_modules
                 if (!isDeclarationFile(sourceFile) && !host.isSourceFileFromExternalLibrary(sourceFile)) {
                     onSingleFileEmit(host, sourceFile);
                 }
@@ -2671,7 +2675,7 @@ namespace ts {
             onBundledEmit(host);
         }
         else {
-            const sourceFiles = targetSourceFile === undefined ? host.getSourceFiles() : [targetSourceFile];
+            const sourceFiles = targetSourceFile === undefined ? getSourceFilesToEmit(host) : [targetSourceFile];
             for (const sourceFile of sourceFiles) {
                 // Don't emit if source file is a declaration file, or was located under node_modules
                 if (!isDeclarationFile(sourceFile) && !host.isSourceFileFromExternalLibrary(sourceFile)) {
@@ -2709,11 +2713,11 @@ namespace ts {
         function onBundledEmit(host: EmitHost) {
             // Can emit only sources that are not declaration file and are either non module code or module with
             // --module or --target es6 specified. Files included by searching under node_modules are also not emitted.
-            const bundledSources = filter(host.getSourceFiles(),
+            const bundledSources = filter(getSourceFilesToEmit(host),
                 sourceFile => !isDeclarationFile(sourceFile) &&
-                              !host.isSourceFileFromExternalLibrary(sourceFile) &&
-                              (!isExternalModule(sourceFile) ||
-                               !!getEmitModuleKind(options)));
+                    !host.isSourceFileFromExternalLibrary(sourceFile) &&
+                    (!isExternalModule(sourceFile) ||
+                        !!getEmitModuleKind(options)));
             if (bundledSources.length) {
                 const jsFilePath = options.outFile || options.out;
                 const emitFileNames: EmitFileNames = {
@@ -2899,7 +2903,7 @@ namespace ts {
         writeComment: (text: string, lineMap: number[], writer: EmitTextWriter, commentPos: number, commentEnd: number, newLine: string) => void,
         node: TextRange, newLine: string, removeComments: boolean) {
         let leadingComments: CommentRange[];
-        let currentDetachedCommentInfo: {nodePos: number, detachedCommentEndPos: number};
+        let currentDetachedCommentInfo: { nodePos: number, detachedCommentEndPos: number };
         if (removeComments) {
             // removeComments is true, only reserve pinned comment at the top of file
             // For example:
@@ -3246,10 +3250,10 @@ namespace ts {
 
     function stringifyValue(value: any): string {
         return typeof value === "string" ? `"${escapeString(value)}"`
-             : typeof value === "number" ? isFinite(value) ? String(value) : "null"
-             : typeof value === "boolean" ? value ? "true" : "false"
-             : typeof value === "object" && value ? isArray(value) ? cycleCheck(stringifyArray, value) : cycleCheck(stringifyObject, value)
-             : /*fallback*/ "null";
+            : typeof value === "number" ? isFinite(value) ? String(value) : "null"
+                : typeof value === "boolean" ? value ? "true" : "false"
+                    : typeof value === "object" && value ? isArray(value) ? cycleCheck(stringifyArray, value) : cycleCheck(stringifyObject, value)
+                        : /*fallback*/ "null";
     }
 
     function cycleCheck(cb: (value: any) => string, value: any) {
@@ -3274,7 +3278,7 @@ namespace ts {
 
     function stringifyProperty(memo: string, value: any, key: string) {
         return value === undefined || typeof value === "function" || key === "__cycle" ? memo
-             : (memo ? memo + "," : memo) + `"${escapeString(key)}":${stringifyValue(value)}`;
+            : (memo ? memo + "," : memo) + `"${escapeString(key)}":${stringifyValue(value)}`;
     }
 
     const base64Digits = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
@@ -3519,7 +3523,7 @@ namespace ts {
      * @param token The token.
      */
     export function createTokenRange(pos: number, token: SyntaxKind): TextRange {
-        return createRange(pos,  pos + tokenToString(token).length);
+        return createRange(pos, pos + tokenToString(token).length);
     }
 
     export function rangeIsOnSingleLine(range: TextRange, sourceFile: SourceFile) {
diff --git a/src/harness/unittests/compileOnSave.ts b/src/harness/unittests/compileOnSave.ts
index 797268000eb48..d7731a625fea2 100644
--- a/src/harness/unittests/compileOnSave.ts
+++ b/src/harness/unittests/compileOnSave.ts
@@ -492,5 +492,45 @@ namespace ts.projectSystem {
             assert.isTrue(host.fileExists(expectedEmittedFileName));
             assert.equal(host.readFile(expectedEmittedFileName), `"use strict";\r\nfunction Foo() { return 10; }\r\nexports.Foo = Foo;\r\n`);
         });
+
+        it("shoud not emit js files in external projects", () => {
+            const file1 = {
+                path: "/a/b/file1.ts",
+                content: "consonle.log('file1');"
+            };
+            // file2 has errors. The emitting should not be blocked.
+            const file2 = {
+                path: "/a/b/file2.js",
+                content: "console.log'file2');"
+            };
+            const file3 = {
+                path: "/a/b/file3.js",
+                content: "console.log('file3');"
+            };
+            const externalProjectName = "externalproject";
+            const host = createServerHost([file1, file2, file3, libFile]);
+            const session = createSession(host);
+            const projectService = session.getProjectService();
+
+            projectService.openExternalProject({
+                rootFiles: toExternalFiles([file1.path, file2.path]),
+                options: {
+                    allowJs: true,
+                    outFile: "dist.js",
+                    compileOnSave: true
+                },
+                projectFileName: externalProjectName
+            });
+
+            const emitRequest = makeSessionRequest<server.protocol.CompileOnSaveEmitFileRequestArgs>(CommandNames.CompileOnSaveEmitFile, { file: file1.path });
+            session.executeCommand(emitRequest);
+
+            const expectedOutFileName = "/a/b/dist.js";
+            assert.isTrue(host.fileExists(expectedOutFileName));
+            const outFileContent = host.readFile(expectedOutFileName);
+            assert.isTrue(outFileContent.indexOf(file1.content) !== -1);
+            assert.isTrue(outFileContent.indexOf(file2.content) === -1);
+            assert.isTrue(outFileContent.indexOf(file3.content) === -1);
+        });
     });
 }
\ No newline at end of file
diff --git a/src/server/project.ts b/src/server/project.ts
index d01df728248c6..db862af7e0d77 100644
--- a/src/server/project.ts
+++ b/src/server/project.ts
@@ -161,8 +161,8 @@ namespace ts.server {
                 this.compilerOptions.allowNonTsExtensions = true;
             }
 
-            if (this.projectKind === ProjectKind.Inferred) {
-                this.compilerOptions.noEmitOverwritenFiles = true;
+            if (this.projectKind === ProjectKind.Inferred || this.projectKind === ProjectKind.External) {
+                this.compilerOptions.noEmitForJsFiles = true;
             }
 
             if (languageServiceEnabled) {

From d537b79c617ac28331f2a3574c97efb6578e784e Mon Sep 17 00:00:00 2001
From: Mohamed Hegazy <mhegazy@microsoft.com>
Date: Thu, 10 Nov 2016 14:28:34 -0800
Subject: [PATCH 224/224] Merge release-2.1 into master (#12157)

* Update LKG

* Update version

* Update LKG

* Skip overloads with too-short function parameters

If the parameter of an overload is a function and the argument is also a
function, skip the overload if the parameter has fewer arguments than
the argument does. That overload cannot possibly apply, and should not
participate in, for example, contextual typing.

Example:

```ts
interface I {
  (a: number): void;
  (b: string, c): void;
}
declare function f(i: I): void;
f((x, y) => {});
```

This code now skips the first overload instead of considering.

This was a longstanding bug but was only uncovered now that more
functions expressions are context sensitive.

* Test skip overloads w/too-short function params

1. Update changed baseline.
2. Add a new test with baseline.

* Minor style improvements

* Ignore optionality when skipping overloads

* Do not use contextual signatures with too few parameters

* isAritySmaller runs later: getNonGenericSignature

* rewrite void-returning statements in constructors that capture result of super call (#11868)

* rewrite void-returning statements in constructors that capture result of super call

* linter

* Update LKG

* Fix emit inferred type which is a generic type-alias both fully and partially fill type parameters

* Add tests and baselines

* Skip trying to use alias if there is target type

* Update baselines

* Add diagnostics to remind adding tsconfig file for certain external project (#11932)

* Add diagnostics for certain external project

* Show tsconfig suggestion

* fix lint error

* Address pr

* fix comment

* Update error message

* Flag for not overwrite js files by default without generating errors (#11980)

* WIP

* Properly naming things

* refactor

* apply the option to all files and check out options

* Fix typo

* Update LKG

* lockLinter

* use local registry to check if typings package exist (#12014) (#12032)

use local registry to check if typings package exist

* Add test for https://github.com/Microsoft/TypeScript/pull/11980 (#12027)

* add test for the fix for overwrite emitting error

* cr feedback

* enable sending telemetry events to tsserver client (#12034) (#12051)

enable sending telemetry events

* Update LKG

* Reuse subtree transform flags for incrementally parsed nodes (#12088)

* Update LKG

* Update version

* Update LKG

* Do not emit "use strict" when targeting es6 or higher or module kind is es2015 and the file is external module

* Add tests and baselines

* [Release 2.1] fix11754 global augmentation (#12133)

* Exclude global augmentation from module resolution logic

* Address PR: check using string literal instead of NodeFlags.globalAugmentation

* Remove comment
---
 src/compiler/checker.ts                       |  2 +-
 src/compiler/program.ts                       |  8 +++--
 src/compiler/transformers/ts.ts               |  6 +++-
 .../typingsInstaller/typingsInstaller.ts      |  4 +--
 .../reference/alwaysStrictModule3.js          |  8 +++++
 .../reference/alwaysStrictModule3.symbols     |  6 ++++
 .../reference/alwaysStrictModule3.types       |  7 ++++
 .../reference/alwaysStrictModule4.js          |  9 +++++
 .../reference/alwaysStrictModule4.symbols     |  6 ++++
 .../reference/alwaysStrictModule4.types       |  7 ++++
 .../reference/alwaysStrictModule5.js          |  8 +++++
 .../reference/alwaysStrictModule5.symbols     |  6 ++++
 .../reference/alwaysStrictModule5.types       |  7 ++++
 .../reference/alwaysStrictModule6.js          |  9 +++++
 .../reference/alwaysStrictModule6.symbols     |  6 ++++
 .../reference/alwaysStrictModule6.types       |  7 ++++
 ...arationEmitTypeAliasWithTypeParameters2.js | 17 ++++++++++
 ...onEmitTypeAliasWithTypeParameters2.symbols | 30 +++++++++++++++++
 ...tionEmitTypeAliasWithTypeParameters2.types | 32 ++++++++++++++++++
 ...arationEmitTypeAliasWithTypeParameters3.js | 21 ++++++++++++
 ...onEmitTypeAliasWithTypeParameters3.symbols | 20 +++++++++++
 ...tionEmitTypeAliasWithTypeParameters3.types | 22 +++++++++++++
 ...arationEmitTypeAliasWithTypeParameters4.js | 24 ++++++++++++++
 ...onEmitTypeAliasWithTypeParameters4.symbols | 29 ++++++++++++++++
 ...tionEmitTypeAliasWithTypeParameters4.types | 31 +++++++++++++++++
 ...mitTypeAliasWithTypeParameters5.errors.txt | 16 +++++++++
 ...arationEmitTypeAliasWithTypeParameters5.js | 17 ++++++++++
 ...arationEmitTypeAliasWithTypeParameters6.js | 24 ++++++++++++++
 ...onEmitTypeAliasWithTypeParameters6.symbols | 31 +++++++++++++++++
 ...tionEmitTypeAliasWithTypeParameters6.types | 33 +++++++++++++++++++
 .../globalAugmentationModuleResolution.js     | 10 ++++++
 ...globalAugmentationModuleResolution.symbols | 10 ++++++
 ...balAugmentationModuleResolution.trace.json |  1 +
 .../globalAugmentationModuleResolution.types  | 10 ++++++
 tests/cases/compiler/alwaysStrictModule3.ts   |  5 +++
 tests/cases/compiler/alwaysStrictModule4.ts   |  5 +++
 tests/cases/compiler/alwaysStrictModule5.ts   |  5 +++
 tests/cases/compiler/alwaysStrictModule6.ts   |  5 +++
 ...arationEmitTypeAliasWithTypeParameters2.ts |  6 ++++
 ...arationEmitTypeAliasWithTypeParameters3.ts |  8 +++++
 ...arationEmitTypeAliasWithTypeParameters4.ts | 10 ++++++
 ...arationEmitTypeAliasWithTypeParameters5.ts | 10 ++++++
 ...arationEmitTypeAliasWithTypeParameters6.ts | 10 ++++++
 .../globalAugmentationModuleResolution.ts     |  8 +++++
 44 files changed, 549 insertions(+), 7 deletions(-)
 create mode 100644 tests/baselines/reference/alwaysStrictModule3.js
 create mode 100644 tests/baselines/reference/alwaysStrictModule3.symbols
 create mode 100644 tests/baselines/reference/alwaysStrictModule3.types
 create mode 100644 tests/baselines/reference/alwaysStrictModule4.js
 create mode 100644 tests/baselines/reference/alwaysStrictModule4.symbols
 create mode 100644 tests/baselines/reference/alwaysStrictModule4.types
 create mode 100644 tests/baselines/reference/alwaysStrictModule5.js
 create mode 100644 tests/baselines/reference/alwaysStrictModule5.symbols
 create mode 100644 tests/baselines/reference/alwaysStrictModule5.types
 create mode 100644 tests/baselines/reference/alwaysStrictModule6.js
 create mode 100644 tests/baselines/reference/alwaysStrictModule6.symbols
 create mode 100644 tests/baselines/reference/alwaysStrictModule6.types
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters2.js
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters2.symbols
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters2.types
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters3.js
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters3.symbols
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters3.types
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters4.js
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters4.symbols
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters4.types
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters5.errors.txt
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters5.js
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters6.js
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters6.symbols
 create mode 100644 tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters6.types
 create mode 100644 tests/baselines/reference/globalAugmentationModuleResolution.js
 create mode 100644 tests/baselines/reference/globalAugmentationModuleResolution.symbols
 create mode 100644 tests/baselines/reference/globalAugmentationModuleResolution.trace.json
 create mode 100644 tests/baselines/reference/globalAugmentationModuleResolution.types
 create mode 100644 tests/cases/compiler/alwaysStrictModule3.ts
 create mode 100644 tests/cases/compiler/alwaysStrictModule4.ts
 create mode 100644 tests/cases/compiler/alwaysStrictModule5.ts
 create mode 100644 tests/cases/compiler/alwaysStrictModule6.ts
 create mode 100644 tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters2.ts
 create mode 100644 tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters3.ts
 create mode 100644 tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters4.ts
 create mode 100644 tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters5.ts
 create mode 100644 tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters6.ts
 create mode 100644 tests/cases/conformance/externalModules/globalAugmentationModuleResolution.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 1510979305beb..7bd8dfae88b61 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -11493,7 +11493,7 @@ namespace ts {
         function checkJsxOpeningLikeElement(node: JsxOpeningLikeElement) {
             checkGrammarJsxElement(node);
             checkJsxPreconditions(node);
-            // The reactNamespace/jsxFactory's root symbol should be marked as 'used' so we don't incorrectly elide its import. 
+            // The reactNamespace/jsxFactory's root symbol should be marked as 'used' so we don't incorrectly elide its import.
             // And if there is no reactNamespace/jsxFactory's symbol in scope when targeting React emit, we should issue an error.
             const reactRefErr = compilerOptions.jsx === JsxEmit.React ? Diagnostics.Cannot_find_name_0 : undefined;
             const reactNamespace = getJsxNamespace();
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 8b53f68bc6f7d..7225b3119331e 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -476,7 +476,7 @@ namespace ts {
                 return resolveModuleNamesWorker(moduleNames, containingFile);
             }
 
-            // at this point we know that either 
+            // at this point we know that either
             // - file has local declarations for ambient modules
             // OR
             // - old program state is available
@@ -670,7 +670,7 @@ namespace ts {
             }
 
             const modifiedFilePaths = modifiedSourceFiles.map(f => f.newFile.path);
-            // try to verify results of module resolution 
+            // try to verify results of module resolution
             for (const { oldFile: oldSourceFile, newFile: newSourceFile } of modifiedSourceFiles) {
                 const newSourceFilePath = getNormalizedAbsolutePath(newSourceFile.fileName, currentDirectory);
                 if (resolveModuleNamesWorker) {
@@ -1447,7 +1447,9 @@ namespace ts {
             collectExternalModuleReferences(file);
             if (file.imports.length || file.moduleAugmentations.length) {
                 file.resolvedModules = createMap<ResolvedModuleFull>();
-                const moduleNames = map(concatenate(file.imports, file.moduleAugmentations), getTextOfLiteral);
+                // Because global augmentation doesn't have string literal name, we can check for global augmentation as such.
+                const nonGlobalAugmentation = filter(file.moduleAugmentations, (moduleAugmentation) => moduleAugmentation.kind === SyntaxKind.StringLiteral);
+                const moduleNames = map(concatenate(file.imports, nonGlobalAugmentation), getTextOfLiteral);
                 const resolutions = resolveModuleNamesReusingOldState(moduleNames, getNormalizedAbsolutePath(file.fileName, currentDirectory), file);
                 Debug.assert(resolutions.length === moduleNames.length);
                 for (let i = 0; i < moduleNames.length; i++) {
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 1362746ba57a8..89fa039100a7e 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -471,7 +471,11 @@ namespace ts {
             currentSourceFile = node;
 
             // ensure "use strict" is emitted in all scenarios in alwaysStrict mode
-            if (compilerOptions.alwaysStrict) {
+            // There is no need to emit "use strict" in the following cases:
+            //      1. The file is an external module and target is es2015 or higher
+            //      or 2. The file is an external module and module-kind is es6 or es2015 as such value is not allowed when targeting es5 or lower
+            if (compilerOptions.alwaysStrict &&
+                !(isExternalModule(node) && (compilerOptions.target >= ScriptTarget.ES2015 || compilerOptions.module === ModuleKind.ES2015))) {
                 node = ensureUseStrict(node);
             }
 
diff --git a/src/server/typingsInstaller/typingsInstaller.ts b/src/server/typingsInstaller/typingsInstaller.ts
index da97dbcd194df..0873d5c328b2a 100644
--- a/src/server/typingsInstaller/typingsInstaller.ts
+++ b/src/server/typingsInstaller/typingsInstaller.ts
@@ -69,7 +69,7 @@ namespace ts.server.typingsInstaller {
         requestId: number;
         args: string[];
         cwd: string;
-        onRequestCompleted: RequestCompletedAction
+        onRequestCompleted: RequestCompletedAction;
     };
 
     export abstract class TypingsInstaller {
@@ -380,7 +380,7 @@ namespace ts.server.typingsInstaller {
                 compilerOptions: request.compilerOptions,
                 typings,
                 unresolvedImports: request.unresolvedImports,
-                kind: server.ActionSet
+                kind: ActionSet
             };
         }
 
diff --git a/tests/baselines/reference/alwaysStrictModule3.js b/tests/baselines/reference/alwaysStrictModule3.js
new file mode 100644
index 0000000000000..894bad25143d9
--- /dev/null
+++ b/tests/baselines/reference/alwaysStrictModule3.js
@@ -0,0 +1,8 @@
+//// [alwaysStrictModule3.ts]
+
+// module ES2015
+export const a = 1;
+
+//// [alwaysStrictModule3.js]
+// module ES2015
+export var a = 1;
diff --git a/tests/baselines/reference/alwaysStrictModule3.symbols b/tests/baselines/reference/alwaysStrictModule3.symbols
new file mode 100644
index 0000000000000..6f053673f0e40
--- /dev/null
+++ b/tests/baselines/reference/alwaysStrictModule3.symbols
@@ -0,0 +1,6 @@
+=== tests/cases/compiler/alwaysStrictModule3.ts ===
+
+// module ES2015
+export const a = 1;
+>a : Symbol(a, Decl(alwaysStrictModule3.ts, 2, 12))
+
diff --git a/tests/baselines/reference/alwaysStrictModule3.types b/tests/baselines/reference/alwaysStrictModule3.types
new file mode 100644
index 0000000000000..75b11206a4f7a
--- /dev/null
+++ b/tests/baselines/reference/alwaysStrictModule3.types
@@ -0,0 +1,7 @@
+=== tests/cases/compiler/alwaysStrictModule3.ts ===
+
+// module ES2015
+export const a = 1;
+>a : 1
+>1 : 1
+
diff --git a/tests/baselines/reference/alwaysStrictModule4.js b/tests/baselines/reference/alwaysStrictModule4.js
new file mode 100644
index 0000000000000..1444f351bbd43
--- /dev/null
+++ b/tests/baselines/reference/alwaysStrictModule4.js
@@ -0,0 +1,9 @@
+//// [alwaysStrictModule4.ts]
+
+// Module commonjs
+export const a = 1
+
+//// [alwaysStrictModule4.js]
+"use strict";
+// Module commonjs
+exports.a = 1;
diff --git a/tests/baselines/reference/alwaysStrictModule4.symbols b/tests/baselines/reference/alwaysStrictModule4.symbols
new file mode 100644
index 0000000000000..4b8a968ae165d
--- /dev/null
+++ b/tests/baselines/reference/alwaysStrictModule4.symbols
@@ -0,0 +1,6 @@
+=== tests/cases/compiler/alwaysStrictModule4.ts ===
+
+// Module commonjs
+export const a = 1
+>a : Symbol(a, Decl(alwaysStrictModule4.ts, 2, 12))
+
diff --git a/tests/baselines/reference/alwaysStrictModule4.types b/tests/baselines/reference/alwaysStrictModule4.types
new file mode 100644
index 0000000000000..fff87967605c9
--- /dev/null
+++ b/tests/baselines/reference/alwaysStrictModule4.types
@@ -0,0 +1,7 @@
+=== tests/cases/compiler/alwaysStrictModule4.ts ===
+
+// Module commonjs
+export const a = 1
+>a : 1
+>1 : 1
+
diff --git a/tests/baselines/reference/alwaysStrictModule5.js b/tests/baselines/reference/alwaysStrictModule5.js
new file mode 100644
index 0000000000000..74b9d72263c4c
--- /dev/null
+++ b/tests/baselines/reference/alwaysStrictModule5.js
@@ -0,0 +1,8 @@
+//// [alwaysStrictModule5.ts]
+
+// Targeting ES6
+export const a = 1; 
+
+//// [alwaysStrictModule5.js]
+// Targeting ES6
+export const a = 1;
diff --git a/tests/baselines/reference/alwaysStrictModule5.symbols b/tests/baselines/reference/alwaysStrictModule5.symbols
new file mode 100644
index 0000000000000..903bf3c5c9893
--- /dev/null
+++ b/tests/baselines/reference/alwaysStrictModule5.symbols
@@ -0,0 +1,6 @@
+=== tests/cases/compiler/alwaysStrictModule5.ts ===
+
+// Targeting ES6
+export const a = 1; 
+>a : Symbol(a, Decl(alwaysStrictModule5.ts, 2, 12))
+
diff --git a/tests/baselines/reference/alwaysStrictModule5.types b/tests/baselines/reference/alwaysStrictModule5.types
new file mode 100644
index 0000000000000..2bfa329ad7e8d
--- /dev/null
+++ b/tests/baselines/reference/alwaysStrictModule5.types
@@ -0,0 +1,7 @@
+=== tests/cases/compiler/alwaysStrictModule5.ts ===
+
+// Targeting ES6
+export const a = 1; 
+>a : 1
+>1 : 1
+
diff --git a/tests/baselines/reference/alwaysStrictModule6.js b/tests/baselines/reference/alwaysStrictModule6.js
new file mode 100644
index 0000000000000..9a60392616977
--- /dev/null
+++ b/tests/baselines/reference/alwaysStrictModule6.js
@@ -0,0 +1,9 @@
+//// [alwaysStrictModule6.ts]
+
+// Targeting ES5
+export const a = 1; 
+
+//// [alwaysStrictModule6.js]
+"use strict";
+// Targeting ES5
+exports.a = 1;
diff --git a/tests/baselines/reference/alwaysStrictModule6.symbols b/tests/baselines/reference/alwaysStrictModule6.symbols
new file mode 100644
index 0000000000000..59a70f3e5b5fe
--- /dev/null
+++ b/tests/baselines/reference/alwaysStrictModule6.symbols
@@ -0,0 +1,6 @@
+=== tests/cases/compiler/alwaysStrictModule6.ts ===
+
+// Targeting ES5
+export const a = 1; 
+>a : Symbol(a, Decl(alwaysStrictModule6.ts, 2, 12))
+
diff --git a/tests/baselines/reference/alwaysStrictModule6.types b/tests/baselines/reference/alwaysStrictModule6.types
new file mode 100644
index 0000000000000..0970380911eb3
--- /dev/null
+++ b/tests/baselines/reference/alwaysStrictModule6.types
@@ -0,0 +1,7 @@
+=== tests/cases/compiler/alwaysStrictModule6.ts ===
+
+// Targeting ES5
+export const a = 1; 
+>a : 1
+>1 : 1
+
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters2.js b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters2.js
new file mode 100644
index 0000000000000..d5bf31bd755aa
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters2.js
@@ -0,0 +1,17 @@
+//// [declarationEmitTypeAliasWithTypeParameters2.ts]
+
+export type Bar<X, Y, Z> = () => [X, Y, Z];
+export type Baz<M, N> = Bar<M, string, N>;
+export type Baa<Y> = Baz<boolean, Y>;
+export const y = (x: Baa<number>) => 1
+
+//// [declarationEmitTypeAliasWithTypeParameters2.js]
+"use strict";
+exports.y = function (x) { return 1; };
+
+
+//// [declarationEmitTypeAliasWithTypeParameters2.d.ts]
+export declare type Bar<X, Y, Z> = () => [X, Y, Z];
+export declare type Baz<M, N> = Bar<M, string, N>;
+export declare type Baa<Y> = Baz<boolean, Y>;
+export declare const y: (x: Bar<boolean, string, number>) => number;
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters2.symbols b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters2.symbols
new file mode 100644
index 0000000000000..cc13e9fd30b24
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters2.symbols
@@ -0,0 +1,30 @@
+=== tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters2.ts ===
+
+export type Bar<X, Y, Z> = () => [X, Y, Z];
+>Bar : Symbol(Bar, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 0, 0))
+>X : Symbol(X, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 1, 16))
+>Y : Symbol(Y, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 1, 18))
+>Z : Symbol(Z, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 1, 21))
+>X : Symbol(X, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 1, 16))
+>Y : Symbol(Y, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 1, 18))
+>Z : Symbol(Z, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 1, 21))
+
+export type Baz<M, N> = Bar<M, string, N>;
+>Baz : Symbol(Baz, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 1, 43))
+>M : Symbol(M, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 2, 16))
+>N : Symbol(N, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 2, 18))
+>Bar : Symbol(Bar, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 0, 0))
+>M : Symbol(M, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 2, 16))
+>N : Symbol(N, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 2, 18))
+
+export type Baa<Y> = Baz<boolean, Y>;
+>Baa : Symbol(Baa, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 2, 42))
+>Y : Symbol(Y, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 3, 16))
+>Baz : Symbol(Baz, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 1, 43))
+>Y : Symbol(Y, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 3, 16))
+
+export const y = (x: Baa<number>) => 1
+>y : Symbol(y, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 4, 12))
+>x : Symbol(x, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 4, 18))
+>Baa : Symbol(Baa, Decl(declarationEmitTypeAliasWithTypeParameters2.ts, 2, 42))
+
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters2.types b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters2.types
new file mode 100644
index 0000000000000..74becc4976558
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters2.types
@@ -0,0 +1,32 @@
+=== tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters2.ts ===
+
+export type Bar<X, Y, Z> = () => [X, Y, Z];
+>Bar : Bar<X, Y, Z>
+>X : X
+>Y : Y
+>Z : Z
+>X : X
+>Y : Y
+>Z : Z
+
+export type Baz<M, N> = Bar<M, string, N>;
+>Baz : Bar<M, string, N>
+>M : M
+>N : N
+>Bar : Bar<X, Y, Z>
+>M : M
+>N : N
+
+export type Baa<Y> = Baz<boolean, Y>;
+>Baa : Bar<boolean, string, Y>
+>Y : Y
+>Baz : Bar<M, string, N>
+>Y : Y
+
+export const y = (x: Baa<number>) => 1
+>y : (x: Bar<boolean, string, number>) => number
+>(x: Baa<number>) => 1 : (x: Bar<boolean, string, number>) => number
+>x : Bar<boolean, string, number>
+>Baa : Bar<boolean, string, Y>
+>1 : 1
+
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters3.js b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters3.js
new file mode 100644
index 0000000000000..9e2a366a685b4
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters3.js
@@ -0,0 +1,21 @@
+//// [declarationEmitTypeAliasWithTypeParameters3.ts]
+
+type Foo<T> = {
+    foo<U>(): Foo<U>
+};
+function bar() {
+    return {} as Foo<number>;
+}
+
+
+//// [declarationEmitTypeAliasWithTypeParameters3.js]
+function bar() {
+    return {};
+}
+
+
+//// [declarationEmitTypeAliasWithTypeParameters3.d.ts]
+declare type Foo<T> = {
+    foo<U>(): Foo<U>;
+};
+declare function bar(): Foo<number>;
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters3.symbols b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters3.symbols
new file mode 100644
index 0000000000000..a18b1372cf14d
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters3.symbols
@@ -0,0 +1,20 @@
+=== tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters3.ts ===
+
+type Foo<T> = {
+>Foo : Symbol(Foo, Decl(declarationEmitTypeAliasWithTypeParameters3.ts, 0, 0))
+>T : Symbol(T, Decl(declarationEmitTypeAliasWithTypeParameters3.ts, 1, 9))
+
+    foo<U>(): Foo<U>
+>foo : Symbol(foo, Decl(declarationEmitTypeAliasWithTypeParameters3.ts, 1, 15))
+>U : Symbol(U, Decl(declarationEmitTypeAliasWithTypeParameters3.ts, 2, 8))
+>Foo : Symbol(Foo, Decl(declarationEmitTypeAliasWithTypeParameters3.ts, 0, 0))
+>U : Symbol(U, Decl(declarationEmitTypeAliasWithTypeParameters3.ts, 2, 8))
+
+};
+function bar() {
+>bar : Symbol(bar, Decl(declarationEmitTypeAliasWithTypeParameters3.ts, 3, 2))
+
+    return {} as Foo<number>;
+>Foo : Symbol(Foo, Decl(declarationEmitTypeAliasWithTypeParameters3.ts, 0, 0))
+}
+
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters3.types b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters3.types
new file mode 100644
index 0000000000000..1b2ff140178c6
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters3.types
@@ -0,0 +1,22 @@
+=== tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters3.ts ===
+
+type Foo<T> = {
+>Foo : Foo<T>
+>T : T
+
+    foo<U>(): Foo<U>
+>foo : <U>() => Foo<U>
+>U : U
+>Foo : Foo<T>
+>U : U
+
+};
+function bar() {
+>bar : () => Foo<number>
+
+    return {} as Foo<number>;
+>{} as Foo<number> : Foo<number>
+>{} : {}
+>Foo : Foo<T>
+}
+
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters4.js b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters4.js
new file mode 100644
index 0000000000000..26908d915e062
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters4.js
@@ -0,0 +1,24 @@
+//// [declarationEmitTypeAliasWithTypeParameters4.ts]
+
+type Foo<T, Y> = {
+    foo<U, J>(): Foo<U, J>
+};
+type SubFoo<R> = Foo<string, R>;
+
+function foo() {
+    return {} as SubFoo<number>;
+}
+
+
+//// [declarationEmitTypeAliasWithTypeParameters4.js]
+function foo() {
+    return {};
+}
+
+
+//// [declarationEmitTypeAliasWithTypeParameters4.d.ts]
+declare type Foo<T, Y> = {
+    foo<U, J>(): Foo<U, J>;
+};
+declare type SubFoo<R> = Foo<string, R>;
+declare function foo(): Foo<string, number>;
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters4.symbols b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters4.symbols
new file mode 100644
index 0000000000000..de73f544645c2
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters4.symbols
@@ -0,0 +1,29 @@
+=== tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters4.ts ===
+
+type Foo<T, Y> = {
+>Foo : Symbol(Foo, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 0, 0))
+>T : Symbol(T, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 1, 9))
+>Y : Symbol(Y, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 1, 11))
+
+    foo<U, J>(): Foo<U, J>
+>foo : Symbol(foo, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 1, 18))
+>U : Symbol(U, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 2, 8))
+>J : Symbol(J, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 2, 10))
+>Foo : Symbol(Foo, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 0, 0))
+>U : Symbol(U, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 2, 8))
+>J : Symbol(J, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 2, 10))
+
+};
+type SubFoo<R> = Foo<string, R>;
+>SubFoo : Symbol(SubFoo, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 3, 2))
+>R : Symbol(R, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 4, 12))
+>Foo : Symbol(Foo, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 0, 0))
+>R : Symbol(R, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 4, 12))
+
+function foo() {
+>foo : Symbol(foo, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 4, 32))
+
+    return {} as SubFoo<number>;
+>SubFoo : Symbol(SubFoo, Decl(declarationEmitTypeAliasWithTypeParameters4.ts, 3, 2))
+}
+
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters4.types b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters4.types
new file mode 100644
index 0000000000000..c545ac6bb0505
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters4.types
@@ -0,0 +1,31 @@
+=== tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters4.ts ===
+
+type Foo<T, Y> = {
+>Foo : Foo<T, Y>
+>T : T
+>Y : Y
+
+    foo<U, J>(): Foo<U, J>
+>foo : <U, J>() => Foo<U, J>
+>U : U
+>J : J
+>Foo : Foo<T, Y>
+>U : U
+>J : J
+
+};
+type SubFoo<R> = Foo<string, R>;
+>SubFoo : Foo<string, R>
+>R : R
+>Foo : Foo<T, Y>
+>R : R
+
+function foo() {
+>foo : () => Foo<string, number>
+
+    return {} as SubFoo<number>;
+>{} as SubFoo<number> : Foo<string, number>
+>{} : {}
+>SubFoo : Foo<string, R>
+}
+
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters5.errors.txt b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters5.errors.txt
new file mode 100644
index 0000000000000..7f683dcc7b7b5
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters5.errors.txt
@@ -0,0 +1,16 @@
+tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters5.ts(5,25): error TS4081: Exported type alias 'SubFoo' has or is using private name 'Foo'.
+
+
+==== tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters5.ts (1 errors) ====
+    
+    type Foo<T, Y> = {
+        foo<U, J>(): Foo<U, J>
+    };
+    export type SubFoo<R> = Foo<string, R>;
+                            ~~~
+!!! error TS4081: Exported type alias 'SubFoo' has or is using private name 'Foo'.
+    
+    function foo() {
+        return {} as SubFoo<number>;
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters5.js b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters5.js
new file mode 100644
index 0000000000000..2f4fff7d72c25
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters5.js
@@ -0,0 +1,17 @@
+//// [declarationEmitTypeAliasWithTypeParameters5.ts]
+
+type Foo<T, Y> = {
+    foo<U, J>(): Foo<U, J>
+};
+export type SubFoo<R> = Foo<string, R>;
+
+function foo() {
+    return {} as SubFoo<number>;
+}
+
+
+//// [declarationEmitTypeAliasWithTypeParameters5.js]
+"use strict";
+function foo() {
+    return {};
+}
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters6.js b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters6.js
new file mode 100644
index 0000000000000..c8001446e3e8c
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters6.js
@@ -0,0 +1,24 @@
+//// [declarationEmitTypeAliasWithTypeParameters6.ts]
+
+type Foo<T, Y> = {
+    foo<U, J>(): Foo<U, J>
+};
+type SubFoo<R, S> = Foo<S, R>;
+
+function foo() {
+    return {} as SubFoo<number, string>;
+}
+
+
+//// [declarationEmitTypeAliasWithTypeParameters6.js]
+function foo() {
+    return {};
+}
+
+
+//// [declarationEmitTypeAliasWithTypeParameters6.d.ts]
+declare type Foo<T, Y> = {
+    foo<U, J>(): Foo<U, J>;
+};
+declare type SubFoo<R, S> = Foo<S, R>;
+declare function foo(): Foo<string, number>;
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters6.symbols b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters6.symbols
new file mode 100644
index 0000000000000..ec29989f0781e
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters6.symbols
@@ -0,0 +1,31 @@
+=== tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters6.ts ===
+
+type Foo<T, Y> = {
+>Foo : Symbol(Foo, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 0, 0))
+>T : Symbol(T, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 1, 9))
+>Y : Symbol(Y, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 1, 11))
+
+    foo<U, J>(): Foo<U, J>
+>foo : Symbol(foo, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 1, 18))
+>U : Symbol(U, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 2, 8))
+>J : Symbol(J, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 2, 10))
+>Foo : Symbol(Foo, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 0, 0))
+>U : Symbol(U, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 2, 8))
+>J : Symbol(J, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 2, 10))
+
+};
+type SubFoo<R, S> = Foo<S, R>;
+>SubFoo : Symbol(SubFoo, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 3, 2))
+>R : Symbol(R, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 4, 12))
+>S : Symbol(S, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 4, 14))
+>Foo : Symbol(Foo, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 0, 0))
+>S : Symbol(S, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 4, 14))
+>R : Symbol(R, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 4, 12))
+
+function foo() {
+>foo : Symbol(foo, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 4, 30))
+
+    return {} as SubFoo<number, string>;
+>SubFoo : Symbol(SubFoo, Decl(declarationEmitTypeAliasWithTypeParameters6.ts, 3, 2))
+}
+
diff --git a/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters6.types b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters6.types
new file mode 100644
index 0000000000000..b02ccbc2be7bc
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeAliasWithTypeParameters6.types
@@ -0,0 +1,33 @@
+=== tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters6.ts ===
+
+type Foo<T, Y> = {
+>Foo : Foo<T, Y>
+>T : T
+>Y : Y
+
+    foo<U, J>(): Foo<U, J>
+>foo : <U, J>() => Foo<U, J>
+>U : U
+>J : J
+>Foo : Foo<T, Y>
+>U : U
+>J : J
+
+};
+type SubFoo<R, S> = Foo<S, R>;
+>SubFoo : Foo<S, R>
+>R : R
+>S : S
+>Foo : Foo<T, Y>
+>S : S
+>R : R
+
+function foo() {
+>foo : () => Foo<string, number>
+
+    return {} as SubFoo<number, string>;
+>{} as SubFoo<number, string> : Foo<string, number>
+>{} : {}
+>SubFoo : Foo<S, R>
+}
+
diff --git a/tests/baselines/reference/globalAugmentationModuleResolution.js b/tests/baselines/reference/globalAugmentationModuleResolution.js
new file mode 100644
index 0000000000000..e1a4ebce8c5de
--- /dev/null
+++ b/tests/baselines/reference/globalAugmentationModuleResolution.js
@@ -0,0 +1,10 @@
+//// [a.ts]
+
+export { };
+
+declare global {
+  var x: number;
+}
+
+//// [a.js]
+"use strict";
diff --git a/tests/baselines/reference/globalAugmentationModuleResolution.symbols b/tests/baselines/reference/globalAugmentationModuleResolution.symbols
new file mode 100644
index 0000000000000..614860d654e97
--- /dev/null
+++ b/tests/baselines/reference/globalAugmentationModuleResolution.symbols
@@ -0,0 +1,10 @@
+=== tests/cases/conformance/externalModules/a.ts ===
+
+export { };
+
+declare global {
+>global : Symbol(global, Decl(a.ts, 1, 11))
+
+  var x: number;
+>x : Symbol(x, Decl(a.ts, 4, 5))
+}
diff --git a/tests/baselines/reference/globalAugmentationModuleResolution.trace.json b/tests/baselines/reference/globalAugmentationModuleResolution.trace.json
new file mode 100644
index 0000000000000..0637a088a01e8
--- /dev/null
+++ b/tests/baselines/reference/globalAugmentationModuleResolution.trace.json
@@ -0,0 +1 @@
+[]
\ No newline at end of file
diff --git a/tests/baselines/reference/globalAugmentationModuleResolution.types b/tests/baselines/reference/globalAugmentationModuleResolution.types
new file mode 100644
index 0000000000000..c057ea2943db4
--- /dev/null
+++ b/tests/baselines/reference/globalAugmentationModuleResolution.types
@@ -0,0 +1,10 @@
+=== tests/cases/conformance/externalModules/a.ts ===
+
+export { };
+
+declare global {
+>global : any
+
+  var x: number;
+>x : number
+}
diff --git a/tests/cases/compiler/alwaysStrictModule3.ts b/tests/cases/compiler/alwaysStrictModule3.ts
new file mode 100644
index 0000000000000..adb93cede3616
--- /dev/null
+++ b/tests/cases/compiler/alwaysStrictModule3.ts
@@ -0,0 +1,5 @@
+// @alwaysStrict: true
+// @module: es2015
+
+// module ES2015
+export const a = 1;
\ No newline at end of file
diff --git a/tests/cases/compiler/alwaysStrictModule4.ts b/tests/cases/compiler/alwaysStrictModule4.ts
new file mode 100644
index 0000000000000..f731e6dd734a0
--- /dev/null
+++ b/tests/cases/compiler/alwaysStrictModule4.ts
@@ -0,0 +1,5 @@
+// @alwaysStrict: true
+// @module: commonjs
+
+// Module commonjs
+export const a = 1
\ No newline at end of file
diff --git a/tests/cases/compiler/alwaysStrictModule5.ts b/tests/cases/compiler/alwaysStrictModule5.ts
new file mode 100644
index 0000000000000..d1ac528837085
--- /dev/null
+++ b/tests/cases/compiler/alwaysStrictModule5.ts
@@ -0,0 +1,5 @@
+// @alwaysStrict: true
+// @target: es6
+
+// Targeting ES6
+export const a = 1; 
\ No newline at end of file
diff --git a/tests/cases/compiler/alwaysStrictModule6.ts b/tests/cases/compiler/alwaysStrictModule6.ts
new file mode 100644
index 0000000000000..064ece1a4e1a9
--- /dev/null
+++ b/tests/cases/compiler/alwaysStrictModule6.ts
@@ -0,0 +1,5 @@
+// @alwaysStrict: true
+// @target: es5
+
+// Targeting ES5
+export const a = 1; 
\ No newline at end of file
diff --git a/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters2.ts b/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters2.ts
new file mode 100644
index 0000000000000..de94ad4998d71
--- /dev/null
+++ b/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters2.ts
@@ -0,0 +1,6 @@
+// @declaration: true
+
+export type Bar<X, Y, Z> = () => [X, Y, Z];
+export type Baz<M, N> = Bar<M, string, N>;
+export type Baa<Y> = Baz<boolean, Y>;
+export const y = (x: Baa<number>) => 1
\ No newline at end of file
diff --git a/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters3.ts b/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters3.ts
new file mode 100644
index 0000000000000..6c7d4799abc39
--- /dev/null
+++ b/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters3.ts
@@ -0,0 +1,8 @@
+// @declaration: true
+
+type Foo<T> = {
+    foo<U>(): Foo<U>
+};
+function bar() {
+    return {} as Foo<number>;
+}
diff --git a/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters4.ts b/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters4.ts
new file mode 100644
index 0000000000000..42bb8097997e4
--- /dev/null
+++ b/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters4.ts
@@ -0,0 +1,10 @@
+// @declaration: true
+
+type Foo<T, Y> = {
+    foo<U, J>(): Foo<U, J>
+};
+type SubFoo<R> = Foo<string, R>;
+
+function foo() {
+    return {} as SubFoo<number>;
+}
diff --git a/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters5.ts b/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters5.ts
new file mode 100644
index 0000000000000..b6334e763374b
--- /dev/null
+++ b/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters5.ts
@@ -0,0 +1,10 @@
+// @declaration: true
+
+type Foo<T, Y> = {
+    foo<U, J>(): Foo<U, J>
+};
+export type SubFoo<R> = Foo<string, R>;
+
+function foo() {
+    return {} as SubFoo<number>;
+}
diff --git a/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters6.ts b/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters6.ts
new file mode 100644
index 0000000000000..9b31302702125
--- /dev/null
+++ b/tests/cases/compiler/declarationEmitTypeAliasWithTypeParameters6.ts
@@ -0,0 +1,10 @@
+// @declaration: true
+
+type Foo<T, Y> = {
+    foo<U, J>(): Foo<U, J>
+};
+type SubFoo<R, S> = Foo<S, R>;
+
+function foo() {
+    return {} as SubFoo<number, string>;
+}
diff --git a/tests/cases/conformance/externalModules/globalAugmentationModuleResolution.ts b/tests/cases/conformance/externalModules/globalAugmentationModuleResolution.ts
new file mode 100644
index 0000000000000..4d87ffcab1398
--- /dev/null
+++ b/tests/cases/conformance/externalModules/globalAugmentationModuleResolution.ts
@@ -0,0 +1,8 @@
+// @traceResolution: true
+
+// @fileName: a.ts
+export { };
+
+declare global {
+  var x: number;
+}
\ No newline at end of file