Perform excess property checking on intersection and union members

Author: weswigham

src/compiler/checker.ts

@@ -7473,6 +7473,13 @@ namespace ts {
             return type.resolvedProperties;
         }
 
+        function getPossiblePropertiesOfUnionType(type: UnionType): Symbol[] {
+            // The following is for effects - getUnionOrIntersectionProperty will cache all the possible union properties into `type`
+            void map(flatMap(type.types, getPropertiesOfType), p => getUnionOrIntersectionProperty(type, p.escapedName));
+            // And we can then (uniquely) fetch them out of the cache, instead of as a result of the above call.
+            return !type.propertyCache ? emptyArray : arrayFrom(type.propertyCache.values());
+        }
+
         function getPropertiesOfType(type: Type): Symbol[] {
             type = getApparentType(type);
             return type.flags & TypeFlags.UnionOrIntersection ?
@@ -7832,7 +7839,7 @@ namespace ts {
             const isUnion = containingType.flags & TypeFlags.Union;
             const excludeModifiers = isUnion ? ModifierFlags.NonPublicAccessibilityModifier : 0;
             // Flags we want to propagate to the result if they exist in all source symbols
-            let commonFlags = isUnion ? SymbolFlags.None : SymbolFlags.Optional;
+            let optionalFlag = isUnion ? SymbolFlags.None : SymbolFlags.Optional;
             let syntheticFlag = CheckFlags.SyntheticMethod;
             let checkFlags = 0;
             for (const current of containingType.types) {
@@ -7841,7 +7848,12 @@ namespace ts {
                     const prop = getPropertyOfType(type, name);
                     const modifiers = prop ? getDeclarationModifierFlagsFromSymbol(prop) : 0;
                     if (prop && !(modifiers & excludeModifiers)) {
-                        commonFlags &= prop.flags;
+                        if (isUnion) {
+                            optionalFlag |= (prop.flags & SymbolFlags.Optional);
+                        }
+                        else {
+                            optionalFlag &= prop.flags;
+                        }
                         const id = "" + getSymbolId(prop);
                         if (!propSet.has(id)) {
                             propSet.set(id, prop);
@@ -7859,10 +7871,11 @@ namespace ts {
                         const indexInfo = !isLateBoundName(name) && (isNumericLiteralName(name) && getIndexInfoOfType(type, IndexKind.Number) || getIndexInfoOfType(type, IndexKind.String));
                         if (indexInfo) {
                             checkFlags |= indexInfo.isReadonly ? CheckFlags.Readonly : 0;
+                            checkFlags |= CheckFlags.WritePartial;
                             indexTypes = append(indexTypes, isTupleType(type) ? getRestTypeOfTupleType(type) || undefinedType : indexInfo.type);
                         }
                         else {
-                            checkFlags |= CheckFlags.Partial;
+                            checkFlags |= CheckFlags.ReadPartial;
                         }
                     }
                 }
@@ -7871,7 +7884,7 @@ namespace ts {
                 return undefined;
             }
             const props = arrayFrom(propSet.values());
-            if (props.length === 1 && !(checkFlags & CheckFlags.Partial) && !indexTypes) {
+            if (props.length === 1 && !(checkFlags & CheckFlags.ReadPartial) && !indexTypes) {
                 return props[0];
             }
             let declarations: Declaration[] | undefined;
@@ -7902,7 +7915,7 @@ namespace ts {
                 propTypes.push(type);
             }
             addRange(propTypes, indexTypes);
-            const result = createSymbol(SymbolFlags.Property | commonFlags, name, syntheticFlag | checkFlags);
+            const result = createSymbol(SymbolFlags.Property | optionalFlag, name, syntheticFlag | checkFlags);
             result.containingType = containingType;
             if (!hasNonUniformValueDeclaration && firstValueDeclaration) {
                 result.valueDeclaration = firstValueDeclaration;
@@ -7939,7 +7952,7 @@ namespace ts {
         function getPropertyOfUnionOrIntersectionType(type: UnionOrIntersectionType, name: __String): Symbol | undefined {
             const property = getUnionOrIntersectionProperty(type, name);
             // We need to filter out partial properties in union types
-            return property && !(getCheckFlags(property) & CheckFlags.Partial) ? property : undefined;
+            return property && !(getCheckFlags(property) & CheckFlags.ReadPartial) ? property : undefined;
         }
 
         /**
@@ -12204,25 +12217,6 @@ namespace ts {
                 }
             }
 
-            function isUnionOrIntersectionTypeWithoutNullableConstituents(type: Type): boolean {
-                if (!(type.flags & TypeFlags.UnionOrIntersection)) {
-                    return false;
-                }
-                // at this point we know that this is union or intersection type possibly with nullable constituents.
-                // check if we still will have compound type if we ignore nullable components.
-                let seenNonNullable = false;
-                for (const t of (<UnionOrIntersectionType>type).types) {
-                    if (t.flags & TypeFlags.Nullable) {
-                        continue;
-                    }
-                    if (seenNonNullable) {
-                        return true;
-                    }
-                    seenNonNullable = true;
-                }
-                return false;
-            }
-
             /**
              * Compare two types and return
              * * Ternary.True if they are related with no assumptions,
@@ -12277,21 +12271,15 @@ namespace ts {
                     isSimpleTypeRelatedTo(source, target, relation, reportErrors ? reportError : undefined)) return Ternary.True;
 
                 const isComparingJsxAttributes = !!(getObjectFlags(source) & ObjectFlags.JsxAttributes);
-                if (isObjectLiteralType(source) && getObjectFlags(source) & ObjectFlags.FreshLiteral) {
+                const isPerformingExcessPropertyChecks = (isObjectLiteralType(source) && getObjectFlags(source) & ObjectFlags.FreshLiteral);
+                if (isPerformingExcessPropertyChecks) {
                     const discriminantType = target.flags & TypeFlags.Union ? findMatchingDiscriminantType(source, target as UnionType) : undefined;
                     if (hasExcessProperties(<FreshObjectLiteralType>source, target, discriminantType, reportErrors)) {
                         if (reportErrors) {
                             reportRelationError(headMessage, source, target);
                         }
                         return Ternary.False;
                     }
-                    // Above we check for excess properties with respect to the entire target type. When union
-                    // and intersection types are further deconstructed on the target side, we don't want to
-                    // make the check again (as it might fail for a partial target type). Therefore we obtain
-                    // the regular source type and proceed with that.
-                    if (isUnionOrIntersectionTypeWithoutNullableConstituents(target) && !discriminantType) {
-                        source = getRegularTypeOfObjectLiteral(source);
-                    }
                 }
 
                 if (relation !== comparableRelation && !isApparentIntersectionConstituent &&
@@ -12327,11 +12315,24 @@ namespace ts {
                 }
                 else {
                     if (target.flags & TypeFlags.Union) {
-                        result = typeRelatedToSomeType(source, <UnionType>target, reportErrors && !(source.flags & TypeFlags.Primitive) && !(target.flags & TypeFlags.Primitive));
+                        result = typeRelatedToSomeType(getRegularTypeOfObjectLiteral(source), <UnionType>target, reportErrors && !(source.flags & TypeFlags.Primitive) && !(target.flags & TypeFlags.Primitive));
+                        if (result && isPerformingExcessPropertyChecks) {
+                            // Validate against excess props using the original `source`
+                            const discriminantType = target.flags & TypeFlags.Union ? findMatchingDiscriminantType(source, target as UnionType) : undefined;
+                            if (!propertiesRelatedTo(source, discriminantType || target, reportErrors)) {
+                                return Ternary.False;
+                            }
+                        }
                     }
                     else if (target.flags & TypeFlags.Intersection) {
                         isIntersectionConstituent = true; // set here to affect the following trio of checks
-                        result = typeRelatedToEachType(source, target as IntersectionType, reportErrors);
+                        result = typeRelatedToEachType(getRegularTypeOfObjectLiteral(source), target as IntersectionType, reportErrors);
+                        if (result && isPerformingExcessPropertyChecks) {
+                            // Validate against excess props using the original `source`
+                            if (!propertiesRelatedTo(source, target, reportErrors)) {
+                                return Ternary.False;
+                            }
+                        }
                     }
                     else if (source.flags & TypeFlags.Intersection) {
                         // Check to see if any constituents of the intersection are immediately related to the target.
@@ -12431,7 +12432,7 @@ namespace ts {
                         // check excess properties against discriminant type only, not the entire union
                         return hasExcessProperties(source, discriminant, /*discriminant*/ undefined, reportErrors);
                     }
-                    for (const prop of getPropertiesOfObjectType(source)) {
+                    for (const prop of getPropertiesOfType(source)) {
                         if (shouldCheckAsExcessProperty(prop, source.symbol) && !isKnownProperty(target, prop.escapedName, isComparingJsxAttributes)) {
                             if (reportErrors) {
                                 // Report error in terms of object types in the target as those are the only ones
@@ -13150,7 +13151,9 @@ namespace ts {
                         }
                     }
                 }
-                const properties = getPropertiesOfObjectType(target);
+                // We only call this for union target types when we're attempting to do excess property checking - in those cases, we want to get _all possible props_
+                // from the target union, across all members
+                const properties = target.flags & TypeFlags.Union ? getPossiblePropertiesOfUnionType(target as UnionType) : getPropertiesOfType(target);
                 for (const targetProp of properties) {
                     if (!(targetProp.flags & SymbolFlags.Prototype)) {
                         const sourceProp = getPropertyOfType(source, targetProp.escapedName);
@@ -14550,9 +14553,9 @@ namespace ts {
         }
 
         function* getUnmatchedProperties(source: Type, target: Type, requireOptionalProperties: boolean, matchDiscriminantProperties: boolean) {
-            const properties = target.flags & TypeFlags.Intersection ? getPropertiesOfUnionOrIntersectionType(<IntersectionType>target) : getPropertiesOfObjectType(target);
+            const properties = target.flags & TypeFlags.Union ? getPossiblePropertiesOfUnionType(target as UnionType) : getPropertiesOfType(target);
             for (const targetProp of properties) {
-                if (requireOptionalProperties || !(targetProp.flags & SymbolFlags.Optional)) {
+                if (requireOptionalProperties || !(targetProp.flags & SymbolFlags.Optional || getCheckFlags(targetProp) & CheckFlags.Partial)) {
                     const sourceProp = getPropertyOfType(source, targetProp.escapedName);
                     if (!sourceProp) {
                         yield targetProp;

src/compiler/types.ts

@@ -3746,19 +3746,21 @@ namespace ts {
         SyntheticProperty = 1 << 1,         // Property in union or intersection type
         SyntheticMethod   = 1 << 2,         // Method in union or intersection type
         Readonly          = 1 << 3,         // Readonly transient symbol
-        Partial           = 1 << 4,         // Synthetic property present in some but not all constituents
-        HasNonUniformType = 1 << 5,         // Synthetic property with non-uniform type in constituents
-        HasLiteralType    = 1 << 6,         // Synthetic property with at least one literal type in constituents
-        ContainsPublic    = 1 << 7,         // Synthetic property with public constituent(s)
-        ContainsProtected = 1 << 8,         // Synthetic property with protected constituent(s)
-        ContainsPrivate   = 1 << 9,         // Synthetic property with private constituent(s)
-        ContainsStatic    = 1 << 10,        // Synthetic property with static constituent(s)
-        Late              = 1 << 11,        // Late-bound symbol for a computed property with a dynamic name
-        ReverseMapped     = 1 << 12,        // Property of reverse-inferred homomorphic mapped type
-        OptionalParameter = 1 << 13,        // Optional parameter
-        RestParameter     = 1 << 14,        // Rest parameter
+        ReadPartial       = 1 << 4,         // Synthetic property present in some but not all constituents
+        WritePartial      = 1 << 5,         // Synthetic property present in some but only satisfied by an index signature in others
+        HasNonUniformType = 1 << 6,         // Synthetic property with non-uniform type in constituents
+        HasLiteralType    = 1 << 7,         // Synthetic property with at least one literal type in constituents
+        ContainsPublic    = 1 << 8,         // Synthetic property with public constituent(s)
+        ContainsProtected = 1 << 9,         // Synthetic property with protected constituent(s)
+        ContainsPrivate   = 1 << 10,         // Synthetic property with private constituent(s)
+        ContainsStatic    = 1 << 11,        // Synthetic property with static constituent(s)
+        Late              = 1 << 12,        // Late-bound symbol for a computed property with a dynamic name
+        ReverseMapped     = 1 << 13,        // Property of reverse-inferred homomorphic mapped type
+        OptionalParameter = 1 << 14,        // Optional parameter
+        RestParameter     = 1 << 15,        // Rest parameter
         Synthetic = SyntheticProperty | SyntheticMethod,
-        Discriminant = HasNonUniformType | HasLiteralType
+        Discriminant = HasNonUniformType | HasLiteralType,
+        Partial = ReadPartial | WritePartial
     }
 
     /* @internal */

tests/baselines/reference/deepExcessPropertyCheckingWhenTargetIsIntersection.errors.txt

@@ -0,0 +1,48 @@
+tests/cases/compiler/deepExcessPropertyCheckingWhenTargetIsIntersection.ts(21,33): error TS2322: Type '{ INVALID_PROP_NAME: string; ariaLabel: string; }' is not assignable to type 'ITestProps'.
+  Object literal may only specify known properties, and 'INVALID_PROP_NAME' does not exist in type 'ITestProps'.
+tests/cases/compiler/deepExcessPropertyCheckingWhenTargetIsIntersection.ts(27,34): error TS2326: Types of property 'icon' are incompatible.
+  Type '{ props: { INVALID_PROP_NAME: string; ariaLabel: string; }; }' is not assignable to type 'NestedProp<ITestProps>'.
+    Types of property 'props' are incompatible.
+      Type '{ INVALID_PROP_NAME: string; ariaLabel: string; }' is not assignable to type 'ITestProps'.
+        Object literal may only specify known properties, and 'INVALID_PROP_NAME' does not exist in type 'ITestProps'.
+
+
+==== tests/cases/compiler/deepExcessPropertyCheckingWhenTargetIsIntersection.ts (2 errors) ====
+    interface StatelessComponent<P = {}> {
+      (props: P & { children?: number }, context?: any): null;
+    }
+     
+    const TestComponent: StatelessComponent<TestProps> = (props) => {
+      return null;
+    }
+     
+    interface ITestProps {
+      ariaLabel?: string;
+    }
+     
+    interface NestedProp<TProps> {
+      props: TProps;
+    }
+     
+    interface TestProps {
+      icon: NestedProp<ITestProps>;
+    }
+     
+    TestComponent({icon: { props: { INVALID_PROP_NAME: 'share', ariaLabel: 'test label' } }});
+                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2322: Type '{ INVALID_PROP_NAME: string; ariaLabel: string; }' is not assignable to type 'ITestProps'.
+!!! error TS2322:   Object literal may only specify known properties, and 'INVALID_PROP_NAME' does not exist in type 'ITestProps'.
+!!! related TS6500 tests/cases/compiler/deepExcessPropertyCheckingWhenTargetIsIntersection.ts:14:3: The expected type comes from property 'props' which is declared here on type 'NestedProp<ITestProps>'
+    
+    const TestComponent2: StatelessComponent<TestProps | {props2: {x: number}}> = (props) => {
+      return null;
+    }
+    
+    TestComponent2({icon: { props: { INVALID_PROP_NAME: 'share', ariaLabel: 'test label' } }});
+                                     ~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2326: Types of property 'icon' are incompatible.
+!!! error TS2326:   Type '{ props: { INVALID_PROP_NAME: string; ariaLabel: string; }; }' is not assignable to type 'NestedProp<ITestProps>'.
+!!! error TS2326:     Types of property 'props' are incompatible.
+!!! error TS2326:       Type '{ INVALID_PROP_NAME: string; ariaLabel: string; }' is not assignable to type 'ITestProps'.
+!!! error TS2326:         Object literal may only specify known properties, and 'INVALID_PROP_NAME' does not exist in type 'ITestProps'.
+    

tests/baselines/reference/deepExcessPropertyCheckingWhenTargetIsIntersection.js

@@ -0,0 +1,39 @@
+//// [deepExcessPropertyCheckingWhenTargetIsIntersection.ts]
+interface StatelessComponent<P = {}> {
+  (props: P & { children?: number }, context?: any): null;
+}
+ 
+const TestComponent: StatelessComponent<TestProps> = (props) => {
+  return null;
+}
+ 
+interface ITestProps {
+  ariaLabel?: string;
+}
+ 
+interface NestedProp<TProps> {
+  props: TProps;
+}
+ 
+interface TestProps {
+  icon: NestedProp<ITestProps>;
+}
+ 
+TestComponent({icon: { props: { INVALID_PROP_NAME: 'share', ariaLabel: 'test label' } }});
+
+const TestComponent2: StatelessComponent<TestProps | {props2: {x: number}}> = (props) => {
+  return null;
+}
+
+TestComponent2({icon: { props: { INVALID_PROP_NAME: 'share', ariaLabel: 'test label' } }});
+
+
+//// [deepExcessPropertyCheckingWhenTargetIsIntersection.js]
+var TestComponent = function (props) {
+    return null;
+};
+TestComponent({ icon: { props: { INVALID_PROP_NAME: 'share', ariaLabel: 'test label' } } });
+var TestComponent2 = function (props) {
+    return null;
+};
+TestComponent2({ icon: { props: { INVALID_PROP_NAME: 'share', ariaLabel: 'test label' } } });