Mapped type support for array subtypes, like microsoft#26063

Author: jablko

src/compiler/checker.ts

@@ -13589,8 +13589,8 @@ namespace ts {
                     return mapType(mappedTypeVariable, t => {
                         if (t.flags & (TypeFlags.AnyOrUnknown | TypeFlags.InstantiableNonPrimitive | TypeFlags.Object | TypeFlags.Intersection) && t !== wildcardType && t !== errorType) {
                             const replacementMapper = createReplacementMapper(typeVariable, t, mapper);
-                            return isArrayType(t) ? instantiateMappedArrayType(t, type, replacementMapper) :
-                                isTupleType(t) ? instantiateMappedTupleType(t, type, replacementMapper) :
+                            return isTupleType(t) ? instantiateMappedTupleType(t, type, replacementMapper) :
+                                t.flags & (TypeFlags.Object | TypeFlags.Intersection) && isArrayLikeType(t) ? instantiateMappedArrayType(t, type, replacementMapper) :
                                 instantiateAnonymousType(type, replacementMapper);
                         }
                         return t;

tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.errors.txt

@@ -26,9 +26,10 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccess2.ts(67,3): error TS232
 tests/cases/conformance/types/keyof/keyofAndIndexedAccess2.ts(68,3): error TS2322: Type '123' is not assignable to type 'T[K]'.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccess2.ts(108,5): error TS2322: Type '123' is not assignable to type 'Type[K]'.
   Type '123' is not assignable to type 'never'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccess2.ts(115,21): error TS2313: Type parameter 'Q' has a circular constraint.
 
 
-==== tests/cases/conformance/types/keyof/keyofAndIndexedAccess2.ts (23 errors) ====
+==== tests/cases/conformance/types/keyof/keyofAndIndexedAccess2.ts (24 errors) ====
     function f1(obj: { a: number, b: 0 | 1, c: string }, k0: 'a', k1: 'a' | 'b', k2: 'a' | 'b' | 'c') {
         obj[k0] = 1;
         obj[k0] = 2;
@@ -195,6 +196,9 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccess2.ts(108,5): error TS23
     type StrictExtract<T, U> = T extends U ? U extends T ? T : never : never;
     type StrictExclude<T, U> = T extends StrictExtract<T, U> ? never : T;
     type A<T> = { [Q in { [P in keyof T]: P; }[keyof T]]: T[Q]; };
+                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2313: Type parameter 'Q' has a circular constraint.
+!!! related TS2751 tests/cases/conformance/types/keyof/keyofAndIndexedAccess2.ts:116:36: Circularity originates in type at this location.
     type B<T, V> = A<{ [Q in keyof T]: StrictExclude<B<T[Q], V>, {}>; }>;
 
     // Repros from #30938

tests/baselines/reference/keyofAndIndexedAccess2.errors.txt

@@ -435,7 +435,7 @@ type A<T> = { [Q in { [P in keyof T]: P; }[keyof T]]: T[Q]; };
 >A : A<T>
 
 type B<T, V> = A<{ [Q in keyof T]: StrictExclude<B<T[Q], V>, {}>; }>;
->B : A<{ [Q in keyof T]: StrictExclude<A<{ [Q in keyof T[Q]]: StrictExclude<A<{ [Q in keyof T[Q][Q]]: StrictExclude<A<{ [Q in keyof T[Q][Q][Q]]: StrictExclude<A<{ [Q in keyof T[Q][Q][Q][Q]]: StrictExclude<A<{ [Q in keyof T[Q][Q][Q][Q][Q]]: StrictExclude<A<{ [Q in keyof T[Q][Q][Q][Q][Q][Q]]: StrictExclude<A<{ [Q in keyof T[Q][Q][Q][Q][Q][Q][Q]]: StrictExclude<A<{ [Q in keyof T[Q][Q][Q][Q][Q][Q][Q][Q]]: StrictExclude<A<{ [Q in keyof T[Q][Q][Q][Q][Q][Q][Q][Q][Q]]: StrictExclude<A<{ [Q in keyof T[Q][Q][Q][Q][Q][Q][Q][Q][Q][Q]]: StrictExclude<A<any>, {}>; }>, {}>; }>, {}>; }>, {}>; }>, {}>; }>, {}>; }>, {}>; }>, {}>; }>, {}>; }>, {}>; }>, {}>; }>
+>B : A<{ [Q in keyof T]: never; }>
 
 // Repros from #30938
 

tests/baselines/reference/keyofAndIndexedAccess2.types

@@ -200,14 +200,14 @@ declare namespace Curry {
     };
 
     type Gaps<T extends any[]> = CleanedGaps<PartialGaps<T>>;
->Gaps : CleanedGaps<PartialGaps<T>>
+>Gaps : NonNullable<PartialGaps<T>[number]>[]
 
     type Curry<F extends ((...args: any) => any)> =
 >Curry : Curry<F>
 >args : any
 
         <T extends any[]>(...args: Tools.Cast<Tools.Cast<T, Gaps<Parameters<F>>>, any[]>) =>
->args : Tools.Cast<Tools.Cast<T, CleanedGaps<PartialGaps<Parameters<F>>>>, any[]>
+>args : Tools.Cast<Tools.Cast<T, NonNullable<PartialGaps<Parameters<F>>[number]>[]>, any[]>
 >Tools : any
 >Tools : any
 

tests/baselines/reference/ramdaToolsNoInfinite.types

@@ -0,0 +1,60 @@
+tests/cases/compiler/specedNoStackBlown.ts(7,50): error TS2315: Type 'SpecValue' is not generic.
+tests/cases/compiler/specedNoStackBlown.ts(7,84): error TS2315: Type 'SpecValue' is not generic.
+tests/cases/compiler/specedNoStackBlown.ts(22,29): error TS2315: Type 'SpecObject' is not generic.
+tests/cases/compiler/specedNoStackBlown.ts(25,13): error TS2456: Type alias 'SpecObject' circularly references itself.
+tests/cases/compiler/specedNoStackBlown.ts(25,81): error TS2315: Type 'SpecValue' is not generic.
+tests/cases/compiler/specedNoStackBlown.ts(27,13): error TS2456: Type alias 'SpecValue' circularly references itself.
+tests/cases/compiler/specedNoStackBlown.ts(30,78): error TS2315: Type 'SpecObject' is not generic.
+
+
+==== tests/cases/compiler/specedNoStackBlown.ts (7 errors) ====
+    // Type definitions for spected 0.7
+    // Project: https://github.com/25th-floor/spected
+    // Definitions by: Benjamin Makus <https://github.com/benneq>
+    // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+    // TypeScript Version: 2.8
+    
+    declare function spected<ROOTINPUT, SPEC extends SpecValue<ROOTINPUT, ROOTINPUT> = SpecValue<ROOTINPUT, ROOTINPUT>>(spec: SPEC, input: ROOTINPUT): Result<ROOTINPUT, SPEC>;
+                                                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2315: Type 'SpecValue' is not generic.
+                                                                                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2315: Type 'SpecValue' is not generic.
+    
+    type Predicate<INPUT, ROOTINPUT> = (value: INPUT, inputs: ROOTINPUT) => boolean;
+    
+    type ErrorMsg<INPUT> =
+        | (string | number | boolean | symbol | null | undefined | object)
+        | ((value: INPUT, field: string) => any);
+    
+    export type Spec<INPUT, ROOTINPUT = any> = [Predicate<INPUT, ROOTINPUT>, ErrorMsg<INPUT>];
+    
+    export type SpecArray<INPUT, ROOTINPUT = any> = Array<Spec<INPUT, ROOTINPUT>>;
+    
+    export type SpecFunction<INPUT, ROOTINPUT = any> = [INPUT] extends [ReadonlyArray<infer U>]
+        ? (value: INPUT) => ReadonlyArray<SpecArray<U, ROOTINPUT>>
+        : [INPUT] extends [object]
+            ? (value: INPUT) => SpecObject<INPUT, ROOTINPUT>
+                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2315: Type 'SpecObject' is not generic.
+            : (value: INPUT) => SpecArray<INPUT, ROOTINPUT>;
+    
+    export type SpecObject<INPUT, ROOTINPUT = any> = Partial<{[key in keyof INPUT]: SpecValue<INPUT[key], ROOTINPUT>}>;
+                ~~~~~~~~~~
+!!! error TS2456: Type alias 'SpecObject' circularly references itself.
+                                                                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2315: Type 'SpecValue' is not generic.
+    
+    export type SpecValue<INPUT, ROOTINPUT = any> = [INPUT] extends [ReadonlyArray<any>]
+                ~~~~~~~~~
+!!! error TS2456: Type alias 'SpecValue' circularly references itself.
+        ? SpecArray<INPUT, ROOTINPUT> | SpecFunction<INPUT, ROOTINPUT>
+            : [INPUT] extends [object]
+                ? SpecArray<INPUT, ROOTINPUT> | SpecFunction<INPUT, ROOTINPUT> | SpecObject<INPUT, ROOTINPUT>
+                                                                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2315: Type 'SpecObject' is not generic.
+                : SpecArray<INPUT, ROOTINPUT> | SpecFunction<INPUT, ROOTINPUT>;
+    
+    export type Result<INPUT, SPEC> = {[key in keyof INPUT]: true | any[] | Result<INPUT[key], any>};
+    
+    export default spected;
+    

tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.errors.txt

@@ -6,7 +6,7 @@
 // TypeScript Version: 2.8
 
 declare function spected<ROOTINPUT, SPEC extends SpecValue<ROOTINPUT, ROOTINPUT> = SpecValue<ROOTINPUT, ROOTINPUT>>(spec: SPEC, input: ROOTINPUT): Result<ROOTINPUT, SPEC>;
->spected : <ROOTINPUT, SPEC extends SpecValue<ROOTINPUT, ROOTINPUT> = SpecValue<ROOTINPUT, ROOTINPUT>>(spec: SPEC, input: ROOTINPUT) => Result<ROOTINPUT, SPEC>
+>spected : <ROOTINPUT, SPEC extends any = any>(spec: SPEC, input: ROOTINPUT) => Result<ROOTINPUT, SPEC>
 >spec : SPEC
 >input : ROOTINPUT
 
@@ -45,10 +45,10 @@ export type SpecFunction<INPUT, ROOTINPUT = any> = [INPUT] extends [ReadonlyArra
 >value : INPUT
 
 export type SpecObject<INPUT, ROOTINPUT = any> = Partial<{[key in keyof INPUT]: SpecValue<INPUT[key], ROOTINPUT>}>;
->SpecObject : Partial<{ [key in keyof INPUT]: SpecValue<INPUT[key], ROOTINPUT>; }>
+>SpecObject : any
 
 export type SpecValue<INPUT, ROOTINPUT = any> = [INPUT] extends [ReadonlyArray<any>]
->SpecValue : SpecValue<INPUT, ROOTINPUT>
+>SpecValue : any
 
     ? SpecArray<INPUT, ROOTINPUT> | SpecFunction<INPUT, ROOTINPUT>
         : [INPUT] extends [object]
@@ -60,5 +60,5 @@ export type Result<INPUT, SPEC> = {[key in keyof INPUT]: true | any[] | Result<I
 >true : true
 
 export default spected;
->spected : <ROOTINPUT, SPEC extends SpecValue<ROOTINPUT, ROOTINPUT> = SpecValue<ROOTINPUT, ROOTINPUT>>(spec: SPEC, input: ROOTINPUT) => Result<ROOTINPUT, SPEC>
+>spected : <ROOTINPUT, SPEC extends any = any>(spec: SPEC, input: ROOTINPUT) => Result<ROOTINPUT, SPEC>