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Fix definitely assignable relation for mapped types #26602

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Merged
merged 4 commits into from
Aug 22, 2018
Merged

Fix definitely assignable relation for mapped types #26602

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056c87f
Ignore constraints of generic mapped types in definitelyAssignableRel…
ahejlsberg Aug 22, 2018
84d1e9f
Accept new baselines
ahejlsberg Aug 22, 2018
74c57ca
Add regression test
ahejlsberg Aug 22, 2018
45eb043
Accept new baselines
ahejlsberg Aug 22, 2018
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3 changes: 3 additions & 0 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -11778,6 +11778,9 @@ namespace ts {
}
return Ternary.False;
}
if (relation === definitelyAssignableRelation && isGenericMappedType(source)) {
return Ternary.False;
}
const sourceIsPrimitive = !!(source.flags & TypeFlags.Primitive);
if (relation !== identityRelation) {
source = getApparentType(source);
Expand Down
2 changes: 1 addition & 1 deletion tests/baselines/reference/mappedTypeNoTypeNoCrash.types
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@@ -1,4 +1,4 @@
=== tests/cases/compiler/mappedTypeNoTypeNoCrash.ts ===
type T0<T> = ({[K in keyof T]}) extends ({[key in K]: T[K]}) ? number : never;
>T0 : number
>T0 : T0<T>

12 changes: 12 additions & 0 deletions tests/baselines/reference/mappedTypesArraysTuples.js
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Expand Up @@ -83,6 +83,14 @@ declare function mapArray<T extends any[]>(arr: T): Mapped<T>;
function acceptMappedArray<T extends any[]>(arr: T) {
acceptArray(mapArray(arr));
}

// Repro from #26163

type Unconstrained<T> = ElementType<Mapped<T>>;
type T1 = Unconstrained<[string, number, boolean]>; // string | number | boolean

type Constrained<T extends any[]> = ElementType<Mapped<T>>;
type T2 = Constrained<[string, number, boolean]>; // string | number | boolean


//// [mappedTypesArraysTuples.js]
Expand Down Expand Up @@ -182,3 +190,7 @@ declare type R2 = ElementType<Mapped<[string, number, boolean]>>;
declare function acceptArray(arr: any[]): void;
declare function mapArray<T extends any[]>(arr: T): Mapped<T>;
declare function acceptMappedArray<T extends any[]>(arr: T): void;
declare type Unconstrained<T> = ElementType<Mapped<T>>;
declare type T1 = Unconstrained<[string, number, boolean]>;
declare type Constrained<T extends any[]> = ElementType<Mapped<T>>;
declare type T2 = Constrained<[string, number, boolean]>;
24 changes: 24 additions & 0 deletions tests/baselines/reference/mappedTypesArraysTuples.symbols
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Expand Up @@ -328,3 +328,27 @@ function acceptMappedArray<T extends any[]>(arr: T) {
>arr : Symbol(arr, Decl(mappedTypesArraysTuples.ts, 81, 44))
}

// Repro from #26163

type Unconstrained<T> = ElementType<Mapped<T>>;
>Unconstrained : Symbol(Unconstrained, Decl(mappedTypesArraysTuples.ts, 83, 1))
>T : Symbol(T, Decl(mappedTypesArraysTuples.ts, 87, 19))
>ElementType : Symbol(ElementType, Decl(mappedTypesArraysTuples.ts, 66, 1))
>Mapped : Symbol(Mapped, Decl(mappedTypesArraysTuples.ts, 70, 59))
>T : Symbol(T, Decl(mappedTypesArraysTuples.ts, 87, 19))

type T1 = Unconstrained<[string, number, boolean]>; // string | number | boolean
>T1 : Symbol(T1, Decl(mappedTypesArraysTuples.ts, 87, 47))
>Unconstrained : Symbol(Unconstrained, Decl(mappedTypesArraysTuples.ts, 83, 1))

type Constrained<T extends any[]> = ElementType<Mapped<T>>;
>Constrained : Symbol(Constrained, Decl(mappedTypesArraysTuples.ts, 88, 51))
>T : Symbol(T, Decl(mappedTypesArraysTuples.ts, 90, 17))
>ElementType : Symbol(ElementType, Decl(mappedTypesArraysTuples.ts, 66, 1))
>Mapped : Symbol(Mapped, Decl(mappedTypesArraysTuples.ts, 70, 59))
>T : Symbol(T, Decl(mappedTypesArraysTuples.ts, 90, 17))

type T2 = Constrained<[string, number, boolean]>; // string | number | boolean
>T2 : Symbol(T2, Decl(mappedTypesArraysTuples.ts, 90, 59))
>Constrained : Symbol(Constrained, Decl(mappedTypesArraysTuples.ts, 88, 51))

14 changes: 14 additions & 0 deletions tests/baselines/reference/mappedTypesArraysTuples.types
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Expand Up @@ -241,3 +241,17 @@ function acceptMappedArray<T extends any[]>(arr: T) {
>arr : T
}

// Repro from #26163

type Unconstrained<T> = ElementType<Mapped<T>>;
>Unconstrained : ElementType<Mapped<T>>

type T1 = Unconstrained<[string, number, boolean]>; // string | number | boolean
>T1 : string | number | boolean

type Constrained<T extends any[]> = ElementType<Mapped<T>>;
>Constrained : ElementType<Mapped<T>>

type T2 = Constrained<[string, number, boolean]>; // string | number | boolean
>T2 : string | number | boolean

8 changes: 8 additions & 0 deletions tests/cases/conformance/types/mapped/mappedTypesArraysTuples.ts
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Expand Up @@ -85,3 +85,11 @@ declare function mapArray<T extends any[]>(arr: T): Mapped<T>;
function acceptMappedArray<T extends any[]>(arr: T) {
acceptArray(mapArray(arr));
}

// Repro from #26163

type Unconstrained<T> = ElementType<Mapped<T>>;
type T1 = Unconstrained<[string, number, boolean]>; // string | number | boolean

type Constrained<T extends any[]> = ElementType<Mapped<T>>;
type T2 = Constrained<[string, number, boolean]>; // string | number | boolean