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Fix relation between generic mapped types and types with index signatures (#38761)
* Fix relation between generic mapped type and type with index signature(s) * Add tests
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5 files changed

+241
-3
lines changed

‎src/compiler/checker.ts

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@@ -17288,9 +17288,10 @@ namespace ts {
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return Ternary.True;
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}
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if (isGenericMappedType(source)) {
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// A generic mapped type { [P in K]: T } is related to an index signature { [x: string]: U }
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// if T is related to U.
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return kind === IndexKind.String ? isRelatedTo(getTemplateTypeFromMappedType(source), targetType, reportErrors) : Ternary.False;
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// A generic mapped type { [P in K]: T } is related to a type with an index signature
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// { [x: string]: U }, and optionally with an index signature { [x: number]: V },
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// if T is related to U and V.
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return getIndexTypeOfType(target, IndexKind.String) ? isRelatedTo(getTemplateTypeFromMappedType(source), targetType, reportErrors) : Ternary.False;
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}
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const indexType = getIndexTypeOfType(source, kind) || kind === IndexKind.Number && getIndexTypeOfType(source, IndexKind.String);
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if (indexType) {

‎tests/baselines/reference/mappedTypeAndIndexSignatureRelation.js

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//// [mappedTypeAndIndexSignatureRelation.ts]
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type Same<T> = { [P in keyof T]: T[P] };
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type T1<T extends Record<PropertyKey, number>> = T;
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type T2<U extends Record<PropertyKey, number>> = T1<Same<U>>;
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// Repro from #38235
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type Foo<IdentifierT extends Record<PropertyKey, PropertyKey>> =
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IdentifierT
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;
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type Bar<IdentifierT extends Record<PropertyKey, PropertyKey>, T> =
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{
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[k in keyof T] : Foo<IdentifierT & { k : k }>
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}
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;
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type Merge2<T> = { [k in keyof T] : T[k] }
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type Bar2<IdentifierT extends Record<PropertyKey, PropertyKey>, T> =
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{
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[k in keyof T]: Foo<Merge2<IdentifierT & { k: k }>>
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}
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;
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type Identity<T> = T;
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type Merge3<T> = Identity<{ [k in keyof T] : T[k] }>
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type Bar3<IdentifierT extends Record<PropertyKey, PropertyKey>, T> =
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{
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[k in keyof T]: Foo<Merge3<IdentifierT & { k: k }>>
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}
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;
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//// [mappedTypeAndIndexSignatureRelation.js]
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"use strict";

‎tests/baselines/reference/mappedTypeAndIndexSignatureRelation.symbols

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=== tests/cases/compiler/mappedTypeAndIndexSignatureRelation.ts ===
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type Same<T> = { [P in keyof T]: T[P] };
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>Same : Symbol(Same, Decl(mappedTypeAndIndexSignatureRelation.ts, 0, 0))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 0, 10))
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>P : Symbol(P, Decl(mappedTypeAndIndexSignatureRelation.ts, 0, 18))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 0, 10))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 0, 10))
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>P : Symbol(P, Decl(mappedTypeAndIndexSignatureRelation.ts, 0, 18))
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type T1<T extends Record<PropertyKey, number>> = T;
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>T1 : Symbol(T1, Decl(mappedTypeAndIndexSignatureRelation.ts, 0, 40))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 2, 8))
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>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
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>PropertyKey : Symbol(PropertyKey, Decl(lib.es5.d.ts, --, --))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 2, 8))
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type T2<U extends Record<PropertyKey, number>> = T1<Same<U>>;
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>T2 : Symbol(T2, Decl(mappedTypeAndIndexSignatureRelation.ts, 2, 51))
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>U : Symbol(U, Decl(mappedTypeAndIndexSignatureRelation.ts, 3, 8))
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>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
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>PropertyKey : Symbol(PropertyKey, Decl(lib.es5.d.ts, --, --))
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>T1 : Symbol(T1, Decl(mappedTypeAndIndexSignatureRelation.ts, 0, 40))
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>Same : Symbol(Same, Decl(mappedTypeAndIndexSignatureRelation.ts, 0, 0))
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>U : Symbol(U, Decl(mappedTypeAndIndexSignatureRelation.ts, 3, 8))
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// Repro from #38235
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type Foo<IdentifierT extends Record<PropertyKey, PropertyKey>> =
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>Foo : Symbol(Foo, Decl(mappedTypeAndIndexSignatureRelation.ts, 3, 61))
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>IdentifierT : Symbol(IdentifierT, Decl(mappedTypeAndIndexSignatureRelation.ts, 7, 9))
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>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
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>PropertyKey : Symbol(PropertyKey, Decl(lib.es5.d.ts, --, --))
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>PropertyKey : Symbol(PropertyKey, Decl(lib.es5.d.ts, --, --))
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IdentifierT
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>IdentifierT : Symbol(IdentifierT, Decl(mappedTypeAndIndexSignatureRelation.ts, 7, 9))
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;
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type Bar<IdentifierT extends Record<PropertyKey, PropertyKey>, T> =
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>Bar : Symbol(Bar, Decl(mappedTypeAndIndexSignatureRelation.ts, 9, 1))
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>IdentifierT : Symbol(IdentifierT, Decl(mappedTypeAndIndexSignatureRelation.ts, 11, 9))
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>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
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>PropertyKey : Symbol(PropertyKey, Decl(lib.es5.d.ts, --, --))
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>PropertyKey : Symbol(PropertyKey, Decl(lib.es5.d.ts, --, --))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 11, 62))
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{
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[k in keyof T] : Foo<IdentifierT & { k : k }>
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 13, 9))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 11, 62))
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>Foo : Symbol(Foo, Decl(mappedTypeAndIndexSignatureRelation.ts, 3, 61))
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>IdentifierT : Symbol(IdentifierT, Decl(mappedTypeAndIndexSignatureRelation.ts, 11, 9))
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 13, 44))
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 13, 9))
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}
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;
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type Merge2<T> = { [k in keyof T] : T[k] }
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>Merge2 : Symbol(Merge2, Decl(mappedTypeAndIndexSignatureRelation.ts, 15, 1))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 17, 12))
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 17, 20))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 17, 12))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 17, 12))
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 17, 20))
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type Bar2<IdentifierT extends Record<PropertyKey, PropertyKey>, T> =
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>Bar2 : Symbol(Bar2, Decl(mappedTypeAndIndexSignatureRelation.ts, 17, 42))
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>IdentifierT : Symbol(IdentifierT, Decl(mappedTypeAndIndexSignatureRelation.ts, 18, 10))
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>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
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>PropertyKey : Symbol(PropertyKey, Decl(lib.es5.d.ts, --, --))
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>PropertyKey : Symbol(PropertyKey, Decl(lib.es5.d.ts, --, --))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 18, 63))
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{
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[k in keyof T]: Foo<Merge2<IdentifierT & { k: k }>>
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 20, 9))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 18, 63))
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>Foo : Symbol(Foo, Decl(mappedTypeAndIndexSignatureRelation.ts, 3, 61))
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>Merge2 : Symbol(Merge2, Decl(mappedTypeAndIndexSignatureRelation.ts, 15, 1))
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>IdentifierT : Symbol(IdentifierT, Decl(mappedTypeAndIndexSignatureRelation.ts, 18, 10))
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 20, 50))
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 20, 9))
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}
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;
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type Identity<T> = T;
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>Identity : Symbol(Identity, Decl(mappedTypeAndIndexSignatureRelation.ts, 22, 1))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 24, 14))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 24, 14))
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type Merge3<T> = Identity<{ [k in keyof T] : T[k] }>
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>Merge3 : Symbol(Merge3, Decl(mappedTypeAndIndexSignatureRelation.ts, 24, 21))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 25, 12))
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>Identity : Symbol(Identity, Decl(mappedTypeAndIndexSignatureRelation.ts, 22, 1))
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 25, 29))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 25, 12))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 25, 12))
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 25, 29))
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type Bar3<IdentifierT extends Record<PropertyKey, PropertyKey>, T> =
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>Bar3 : Symbol(Bar3, Decl(mappedTypeAndIndexSignatureRelation.ts, 25, 52))
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>IdentifierT : Symbol(IdentifierT, Decl(mappedTypeAndIndexSignatureRelation.ts, 26, 10))
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>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
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>PropertyKey : Symbol(PropertyKey, Decl(lib.es5.d.ts, --, --))
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>PropertyKey : Symbol(PropertyKey, Decl(lib.es5.d.ts, --, --))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 26, 63))
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{
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[k in keyof T]: Foo<Merge3<IdentifierT & { k: k }>>
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 28, 9))
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>T : Symbol(T, Decl(mappedTypeAndIndexSignatureRelation.ts, 26, 63))
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>Foo : Symbol(Foo, Decl(mappedTypeAndIndexSignatureRelation.ts, 3, 61))
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>Merge3 : Symbol(Merge3, Decl(mappedTypeAndIndexSignatureRelation.ts, 24, 21))
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>IdentifierT : Symbol(IdentifierT, Decl(mappedTypeAndIndexSignatureRelation.ts, 26, 10))
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 28, 50))
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>k : Symbol(k, Decl(mappedTypeAndIndexSignatureRelation.ts, 28, 9))
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}
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;
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‎tests/baselines/reference/mappedTypeAndIndexSignatureRelation.types

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=== tests/cases/compiler/mappedTypeAndIndexSignatureRelation.ts ===
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type Same<T> = { [P in keyof T]: T[P] };
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>Same : Same<T>
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type T1<T extends Record<PropertyKey, number>> = T;
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>T1 : T
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type T2<U extends Record<PropertyKey, number>> = T1<Same<U>>;
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>T2 : Same<U>
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// Repro from #38235
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type Foo<IdentifierT extends Record<PropertyKey, PropertyKey>> =
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>Foo : IdentifierT
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IdentifierT
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;
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type Bar<IdentifierT extends Record<PropertyKey, PropertyKey>, T> =
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>Bar : Bar<IdentifierT, T>
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{
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[k in keyof T] : Foo<IdentifierT & { k : k }>
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>k : k
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}
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;
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type Merge2<T> = { [k in keyof T] : T[k] }
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>Merge2 : Merge2<T>
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type Bar2<IdentifierT extends Record<PropertyKey, PropertyKey>, T> =
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>Bar2 : Bar2<IdentifierT, T>
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{
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[k in keyof T]: Foo<Merge2<IdentifierT & { k: k }>>
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>k : k
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}
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;
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type Identity<T> = T;
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>Identity : T
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type Merge3<T> = Identity<{ [k in keyof T] : T[k] }>
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>Merge3 : { [k in keyof T]: T[k]; }
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type Bar3<IdentifierT extends Record<PropertyKey, PropertyKey>, T> =
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>Bar3 : Bar3<IdentifierT, T>
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{
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[k in keyof T]: Foo<Merge3<IdentifierT & { k: k }>>
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>k : k
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}
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;
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‎tests/cases/compiler/mappedTypeAndIndexSignatureRelation.ts

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// @strict: true
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type Same<T> = { [P in keyof T]: T[P] };
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type T1<T extends Record<PropertyKey, number>> = T;
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type T2<U extends Record<PropertyKey, number>> = T1<Same<U>>;
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// Repro from #38235
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type Foo<IdentifierT extends Record<PropertyKey, PropertyKey>> =
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IdentifierT
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;
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type Bar<IdentifierT extends Record<PropertyKey, PropertyKey>, T> =
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{
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[k in keyof T] : Foo<IdentifierT & { k : k }>
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}
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;
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type Merge2<T> = { [k in keyof T] : T[k] }
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type Bar2<IdentifierT extends Record<PropertyKey, PropertyKey>, T> =
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{
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[k in keyof T]: Foo<Merge2<IdentifierT & { k: k }>>
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}
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;
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type Identity<T> = T;
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type Merge3<T> = Identity<{ [k in keyof T] : T[k] }>
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type Bar3<IdentifierT extends Record<PropertyKey, PropertyKey>, T> =
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{
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[k in keyof T]: Foo<Merge3<IdentifierT & { k: k }>>
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}
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;

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