Generalize performance enhancement

Author: weswigham

src/compiler/checker.ts

@@ -18219,18 +18219,18 @@ namespace ts {
                     return result;
                 }
 
-                if (isNonAugmentingArraySubtype(source) && isArrayType(target)) {
-                    let sourceBase = getBaseTypes((source as TypeReference).target as InterfaceType)[0];
-                    if (length(target.resolvedTypeArguments) === 2) {
-                        sourceBase = getTypeWithThisArgument(sourceBase, ((source as TypeReference).target as InterfaceType).thisType);
+                let sourceBase = getSingleBaseForNonAugmentingSubtype(source);
+                if (sourceBase) {
+                    if (getObjectFlags(target) & ObjectFlags.Reference && length(getTypeArguments((target as TypeReference))) > length((target as TypeReference).target.typeParameters)) {
+                        sourceBase = getTypeWithThisArgument(sourceBase, last(getTypeArguments(source as TypeReference)));
                     }
                     return isRelatedTo(sourceBase, target, reportErrors);
                 }
 
-                if (isArrayType(source) && isNonAugmentingArraySubtype(target)) {
-                    let targetBase = getBaseTypes((target as TypeReference).target as InterfaceType)[0];
-                    if (length(source.resolvedTypeArguments) === 2) {
-                        targetBase = getTypeWithThisArgument(targetBase, ((target as TypeReference).target as InterfaceType).thisType);
+                let targetBase = getSingleBaseForNonAugmentingSubtype(target);
+                if (targetBase) {
+                    if (getObjectFlags(source) & ObjectFlags.Reference && length(getTypeArguments((source as TypeReference))) > length((source as TypeReference).target.typeParameters)) {
+                        targetBase = getTypeWithThisArgument(targetBase, last(getTypeArguments(target as TypeReference)));
                     }
                     return isRelatedTo(source, targetBase, reportErrors);
                 }
@@ -19917,22 +19917,19 @@ namespace ts {
             return isArrayType(type) || !(type.flags & TypeFlags.Nullable) && isTypeAssignableTo(type, anyReadonlyArrayType);
         }
 
-        function isNonAugmentingArraySubtype(type: Type) {
+        function getSingleBaseForNonAugmentingSubtype(type: Type) {
             if (!(getObjectFlags(type) & ObjectFlags.Reference) || !(getObjectFlags((type as TypeReference).target) & ObjectFlags.ClassOrInterface)) {
-                return false;
+                return undefined;
             }
             const target = (type as TypeReference).target as InterfaceType;
             const bases = getBaseTypes(target);
             if (bases.length !== 1) {
-                return false;
-            }
-            if (!isArrayType(bases[0])) {
-                return false;
+                return undefined;
             }
             if (getMembersOfSymbol(type.symbol).size) {
-                return false; // If the interface has any members, they may subtype members in the base, so we should do a full structural comparison
+                return undefined; // If the interface has any members, they may subtype members in the base, so we should do a full structural comparison
             }
-            return true;
+            return !length(target.typeParameters) ? bases[0] : instantiateType(bases[0], createTypeMapper(target.typeParameters!, getTypeArguments(type as TypeReference).slice(0, target.typeParameters!.length)));
         }
 
         function isEmptyArrayLiteralType(type: Type): boolean {

tests/baselines/reference/assignmentCompatWithObjectMembersAccessibility.errors.txt

@@ -17,7 +17,7 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignme
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(81,5): error TS2322: Type 'Base' is not assignable to type '{ foo: string; }'.
   Property 'foo' is private in type 'Base' but not in type '{ foo: string; }'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(82,5): error TS2322: Type 'I' is not assignable to type '{ foo: string; }'.
-  Property 'foo' is private in type 'I' but not in type '{ foo: string; }'.
+  Type 'Base' is not assignable to type '{ foo: string; }'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(84,5): error TS2322: Type 'E' is not assignable to type '{ foo: string; }'.
   Property 'foo' is private in type 'E' but not in type '{ foo: string; }'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(86,5): error TS2322: Type '{ foo: string; }' is not assignable to type 'Base'.
@@ -27,23 +27,23 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignme
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(89,5): error TS2322: Type 'E' is not assignable to type 'Base'.
   Types have separate declarations of a private property 'foo'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(92,5): error TS2322: Type '{ foo: string; }' is not assignable to type 'I'.
-  Property 'foo' is private in type 'I' but not in type '{ foo: string; }'.
+  Type '{ foo: string; }' is not assignable to type 'Base'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(94,5): error TS2322: Type 'D' is not assignable to type 'I'.
-  Property 'foo' is private in type 'I' but not in type 'D'.
+  Type 'D' is not assignable to type 'Base'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(95,5): error TS2322: Type 'E' is not assignable to type 'I'.
-  Types have separate declarations of a private property 'foo'.
+  Type 'E' is not assignable to type 'Base'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(99,5): error TS2322: Type 'Base' is not assignable to type 'D'.
   Property 'foo' is private in type 'Base' but not in type 'D'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(100,5): error TS2322: Type 'I' is not assignable to type 'D'.
-  Property 'foo' is private in type 'I' but not in type 'D'.
+  Type 'Base' is not assignable to type 'D'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(101,5): error TS2322: Type 'E' is not assignable to type 'D'.
   Property 'foo' is private in type 'E' but not in type 'D'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(103,5): error TS2322: Type '{ foo: string; }' is not assignable to type 'E'.
   Property 'foo' is private in type 'E' but not in type '{ foo: string; }'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(104,5): error TS2322: Type 'Base' is not assignable to type 'E'.
   Types have separate declarations of a private property 'foo'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(105,5): error TS2322: Type 'I' is not assignable to type 'E'.
-  Types have separate declarations of a private property 'foo'.
+  Type 'Base' is not assignable to type 'E'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignmentCompatWithObjectMembersAccessibility.ts(106,5): error TS2322: Type 'D' is not assignable to type 'E'.
   Property 'foo' is private in type 'E' but not in type 'D'.
 
@@ -160,7 +160,7 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignme
         a = i; // error
         ~
 !!! error TS2322: Type 'I' is not assignable to type '{ foo: string; }'.
-!!! error TS2322:   Property 'foo' is private in type 'I' but not in type '{ foo: string; }'.
+!!! error TS2322:   Type 'Base' is not assignable to type '{ foo: string; }'.
         a = d;
         a = e; // error
         ~
@@ -185,16 +185,16 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignme
         i = a; // error
         ~
 !!! error TS2322: Type '{ foo: string; }' is not assignable to type 'I'.
-!!! error TS2322:   Property 'foo' is private in type 'I' but not in type '{ foo: string; }'.
+!!! error TS2322:   Type '{ foo: string; }' is not assignable to type 'Base'.
         i = b;
         i = d; // error
         ~
 !!! error TS2322: Type 'D' is not assignable to type 'I'.
-!!! error TS2322:   Property 'foo' is private in type 'I' but not in type 'D'.
+!!! error TS2322:   Type 'D' is not assignable to type 'Base'.
         i = e; // error
         ~
 !!! error TS2322: Type 'E' is not assignable to type 'I'.
-!!! error TS2322:   Types have separate declarations of a private property 'foo'.
+!!! error TS2322:   Type 'E' is not assignable to type 'Base'.
         i = i;
 
         d = a;
@@ -205,7 +205,7 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignme
         d = i; // error
         ~
 !!! error TS2322: Type 'I' is not assignable to type 'D'.
-!!! error TS2322:   Property 'foo' is private in type 'I' but not in type 'D'.
+!!! error TS2322:   Type 'Base' is not assignable to type 'D'.
         d = e; // error
         ~
 !!! error TS2322: Type 'E' is not assignable to type 'D'.
@@ -222,7 +222,7 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/assignme
         e = i; // errror
         ~
 !!! error TS2322: Type 'I' is not assignable to type 'E'.
-!!! error TS2322:   Types have separate declarations of a private property 'foo'.
+!!! error TS2322:   Type 'Base' is not assignable to type 'E'.
         e = d; // errror
         ~
 !!! error TS2322: Type 'D' is not assignable to type 'E'.

tests/baselines/reference/checkJsxChildrenProperty5.errors.txt

@@ -1,5 +1,6 @@
 tests/cases/conformance/jsx/file.tsx(20,10): error TS2741: Property 'children' is missing in type '{ a: number; b: string; }' but required in type 'Prop'.
-tests/cases/conformance/jsx/file.tsx(25,9): error TS2740: Type 'Element' is missing the following properties from type 'Button': render, setState, forceUpdate, state, and 2 more.
+tests/cases/conformance/jsx/file.tsx(25,9): error TS2322: Type 'Element' is not assignable to type 'Button'.
+  Type 'ReactElement<any>' is missing the following properties from type 'Button': render, setState, forceUpdate, state, and 2 more.
 tests/cases/conformance/jsx/file.tsx(29,10): error TS2740: Type 'typeof Button' is missing the following properties from type 'Button': render, setState, forceUpdate, props, and 3 more.
 
 
@@ -33,7 +34,8 @@ tests/cases/conformance/jsx/file.tsx(29,10): error TS2740: Type 'typeof Button'
         <Comp a={10} b="hi">
             <Button />
             ~~~~~~~~~~
-!!! error TS2740: Type 'Element' is missing the following properties from type 'Button': render, setState, forceUpdate, state, and 2 more.
+!!! error TS2322: Type 'Element' is not assignable to type 'Button'.
+!!! error TS2322:   Type 'ReactElement<any>' is missing the following properties from type 'Button': render, setState, forceUpdate, state, and 2 more.
 !!! related TS6500 tests/cases/conformance/jsx/file.tsx:6:5: The expected type comes from property 'children' which is declared here on type 'IntrinsicAttributes & Prop'
         </Comp>;
     let k2 =

tests/baselines/reference/checkJsxChildrenProperty7.errors.txt

@@ -1,4 +1,5 @@
 tests/cases/conformance/jsx/file.tsx(24,40): error TS2747: 'Comp' components don't accept text as child elements. Text in JSX has the type 'string', but the expected type of 'children' is 'Element | Element[]'.
+  Type 'string' is not assignable to type 'ReactElement<any>'.
 tests/cases/conformance/jsx/file.tsx(26,22): error TS2747: 'Comp' components don't accept text as child elements. Text in JSX has the type 'string', but the expected type of 'children' is 'Element | Element[]'.
 tests/cases/conformance/jsx/file.tsx(27,30): error TS2747: 'Comp' components don't accept text as child elements. Text in JSX has the type 'string', but the expected type of 'children' is 'Element | Element[]'.
 
@@ -30,6 +31,7 @@ tests/cases/conformance/jsx/file.tsx(27,30): error TS2747: 'Comp' components don
     let k1 = <Comp a={10} b="hi"><Button />  <AnotherButton /></Comp>;
                                            ~~
 !!! error TS2747: 'Comp' components don't accept text as child elements. Text in JSX has the type 'string', but the expected type of 'children' is 'Element | Element[]'.
+!!! error TS2747:   Type 'string' is not assignable to type 'ReactElement<any>'.
     let k2 = <Comp a={10} b="hi"><Button />
         <AnotherButton />  </Comp>;
                          ~~

tests/baselines/reference/classImplementsClass4.errors.txt

@@ -1,6 +1,7 @@
 tests/cases/compiler/classImplementsClass4.ts(5,7): error TS2720: Class 'C' incorrectly implements class 'A'. Did you mean to extend 'A' and inherit its members as a subclass?
   Property 'x' is missing in type 'C' but required in type 'A'.
-tests/cases/compiler/classImplementsClass4.ts(16,1): error TS2741: Property 'x' is missing in type 'C' but required in type 'C2'.
+tests/cases/compiler/classImplementsClass4.ts(16,1): error TS2322: Type 'C' is not assignable to type 'C2'.
+  Property 'x' is missing in type 'C' but required in type 'A'.
 
 
 ==== tests/cases/compiler/classImplementsClass4.ts (2 errors) ====
@@ -25,5 +26,6 @@ tests/cases/compiler/classImplementsClass4.ts(16,1): error TS2741: Property 'x'
     c = c2;
     c2 = c;
     ~~
-!!! error TS2741: Property 'x' is missing in type 'C' but required in type 'C2'.
+!!! error TS2322: Type 'C' is not assignable to type 'C2'.
+!!! error TS2322:   Property 'x' is missing in type 'C' but required in type 'A'.
 !!! related TS2728 tests/cases/compiler/classImplementsClass4.ts:2:13: 'x' is declared here.

tests/baselines/reference/classImplementsClass5.errors.txt

@@ -1,9 +1,11 @@
 tests/cases/compiler/classImplementsClass5.ts(5,7): error TS2720: Class 'C' incorrectly implements class 'A'. Did you mean to extend 'A' and inherit its members as a subclass?
   Types have separate declarations of a private property 'x'.
 tests/cases/compiler/classImplementsClass5.ts(16,1): error TS2322: Type 'C2' is not assignable to type 'C'.
-  Types have separate declarations of a private property 'x'.
+  Type 'A' is not assignable to type 'C'.
+    Types have separate declarations of a private property 'x'.
 tests/cases/compiler/classImplementsClass5.ts(17,1): error TS2322: Type 'C' is not assignable to type 'C2'.
-  Types have separate declarations of a private property 'x'.
+  Type 'C' is not assignable to type 'A'.
+    Types have separate declarations of a private property 'x'.
 
 
 ==== tests/cases/compiler/classImplementsClass5.ts (3 errors) ====
@@ -28,8 +30,10 @@ tests/cases/compiler/classImplementsClass5.ts(17,1): error TS2322: Type 'C' is n
     c = c2;
     ~
 !!! error TS2322: Type 'C2' is not assignable to type 'C'.
-!!! error TS2322:   Types have separate declarations of a private property 'x'.
+!!! error TS2322:   Type 'A' is not assignable to type 'C'.
+!!! error TS2322:     Types have separate declarations of a private property 'x'.
     c2 = c;
     ~~
 !!! error TS2322: Type 'C' is not assignable to type 'C2'.
-!!! error TS2322:   Types have separate declarations of a private property 'x'.
+!!! error TS2322:   Type 'C' is not assignable to type 'A'.
+!!! error TS2322:     Types have separate declarations of a private property 'x'.

tests/baselines/reference/crashInsourcePropertyIsRelatableToTargetProperty.errors.txt

@@ -1,4 +1,5 @@
-tests/cases/compiler/crashInsourcePropertyIsRelatableToTargetProperty.ts(9,5): error TS2741: Property 'x' is missing in type '(x: "hi", items: string[]) => typeof foo' but required in type 'D'.
+tests/cases/compiler/crashInsourcePropertyIsRelatableToTargetProperty.ts(9,5): error TS2322: Type '(x: "hi", items: string[]) => typeof foo' is not assignable to type 'D'.
+  Property 'x' is missing in type '(x: "hi", items: string[]) => typeof foo' but required in type 'C'.
 
 
 ==== tests/cases/compiler/crashInsourcePropertyIsRelatableToTargetProperty.ts (1 errors) ====
@@ -12,6 +13,7 @@ tests/cases/compiler/crashInsourcePropertyIsRelatableToTargetProperty.ts(9,5): e
     }
     var a: D = foo("hi", []);
         ~
-!!! error TS2741: Property 'x' is missing in type '(x: "hi", items: string[]) => typeof foo' but required in type 'D'.
+!!! error TS2322: Type '(x: "hi", items: string[]) => typeof foo' is not assignable to type 'D'.
+!!! error TS2322:   Property 'x' is missing in type '(x: "hi", items: string[]) => typeof foo' but required in type 'C'.
 !!! related TS2728 tests/cases/compiler/crashInsourcePropertyIsRelatableToTargetProperty.ts:2:13: 'x' is declared here.
 

tests/baselines/reference/implementingAnInterfaceExtendingClassWithProtecteds.errors.txt

@@ -7,7 +7,8 @@ tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInte
 tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts(21,7): error TS2420: Class 'Bar4' incorrectly implements interface 'I'.
   Property 'x' is protected but type 'Bar4' is not a class derived from 'Foo'.
 tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts(26,7): error TS2420: Class 'Bar5' incorrectly implements interface 'I'.
-  Property 'y' is missing in type 'Bar5' but required in type 'I'.
+  Type 'Foo' is not assignable to type 'I'.
+    Property 'y' is missing in type 'Foo' but required in type 'I'.
 tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts(29,7): error TS2420: Class 'Bar6' incorrectly implements interface 'I'.
   Property 'y' is protected in type 'Bar6' but public in type 'I'.
 
@@ -54,7 +55,8 @@ tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInte
     class Bar5 extends Foo implements I { // error
           ~~~~
 !!! error TS2420: Class 'Bar5' incorrectly implements interface 'I'.
-!!! error TS2420:   Property 'y' is missing in type 'Bar5' but required in type 'I'.
+!!! error TS2420:   Type 'Foo' is not assignable to type 'I'.
+!!! error TS2420:     Property 'y' is missing in type 'Foo' but required in type 'I'.
 !!! related TS2728 tests/cases/conformance/interfaces/interfacesExtendingClasses/implementingAnInterfaceExtendingClassWithProtecteds.ts:6:5: 'y' is declared here.
     }