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Merge pull request microsoft#21744 from Microsoft/fixGetConstrainedTypeParameter
Fix getConstrainedTypeParameter function
2 parents c9ccf72 + a7437fd commit 22fbb8e

7 files changed

Lines changed: 58 additions & 2 deletions

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‎src/compiler/checker.ts‎

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@@ -7245,7 +7245,7 @@ namespace ts {
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function getConstrainedTypeParameter(typeParameter: TypeParameter, node: Node) {
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let constraints: Type[];
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while (isTypeNode(node)) {
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while (isPartOfTypeNode(node)) {
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const parent = node.parent;
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if (parent.kind === SyntaxKind.ConditionalType && node === (<ConditionalTypeNode>parent).trueType) {
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if (getTypeFromTypeNode((<ConditionalTypeNode>parent).checkType) === typeParameter) {

‎src/compiler/utilities.ts‎

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@@ -771,6 +771,8 @@ namespace ts {
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return node.parent.kind !== SyntaxKind.VoidExpression;
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case SyntaxKind.ExpressionWithTypeArguments:
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return !isExpressionWithTypeArgumentsInClassExtendsClause(node);
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case SyntaxKind.TypeParameter:
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return node.parent.kind === SyntaxKind.MappedType || node.parent.kind === SyntaxKind.InferType;
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// Identifiers and qualified names may be type nodes, depending on their context. Climb
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// above them to find the lowest container

‎tests/baselines/reference/inferTypes1.errors.txt‎

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@@ -12,9 +12,10 @@ tests/cases/conformance/types/conditional/inferTypes1.ts(72,43): error TS2304: C
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tests/cases/conformance/types/conditional/inferTypes1.ts(72,43): error TS4081: Exported type alias 'T62' has or is using private name 'U'.
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tests/cases/conformance/types/conditional/inferTypes1.ts(78,44): error TS2344: Type 'U' does not satisfy the constraint 'string'.
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Type 'number' is not assignable to type 'string'.
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tests/cases/conformance/types/conditional/inferTypes1.ts(131,40): error TS2322: Type 'T' is not assignable to type 'string'.
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==== tests/cases/conformance/types/conditional/inferTypes1.ts (12 errors) ====
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==== tests/cases/conformance/types/conditional/inferTypes1.ts (13 errors) ====
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type Unpacked<T> =
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T extends (infer U)[] ? U :
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T extends (...args: any[]) => infer U ? U :
@@ -167,4 +168,11 @@ tests/cases/conformance/types/conditional/inferTypes1.ts(78,44): error TS2344: T
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type A2<T, U extends void> = [T, U];
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type B2<S> = S extends A2<infer T, infer U> ? [T, U] : never;
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type C2<S, U extends void> = S extends A2<infer T, U> ? [T, U] : never;
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// Repro from #21735
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type A<T> = T extends string ? { [P in T]: void; } : T;
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type B<T> = string extends T ? { [P in T]: void; } : T; // Error
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~
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!!! error TS2322: Type 'T' is not assignable to type 'string'.
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‎tests/baselines/reference/inferTypes1.js‎

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@@ -125,6 +125,11 @@ type B1<S> = S extends A1<infer T, infer U> ? [T, U] : never;
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type A2<T, U extends void> = [T, U];
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type B2<S> = S extends A2<infer T, infer U> ? [T, U] : never;
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type C2<S, U extends void> = S extends A2<infer T, U> ? [T, U] : never;
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// Repro from #21735
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type A<T> = T extends string ? { [P in T]: void; } : T;
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type B<T> = string extends T ? { [P in T]: void; } : T; // Error
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//// [inferTypes1.js]

‎tests/baselines/reference/inferTypes1.symbols‎

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@@ -551,3 +551,21 @@ type C2<S, U extends void> = S extends A2<infer T, U> ? [T, U] : never;
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>T : Symbol(T, Decl(inferTypes1.ts, 125, 47))
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>U : Symbol(U, Decl(inferTypes1.ts, 125, 10))
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// Repro from #21735
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type A<T> = T extends string ? { [P in T]: void; } : T;
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>A : Symbol(A, Decl(inferTypes1.ts, 125, 71))
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>T : Symbol(T, Decl(inferTypes1.ts, 129, 7))
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>T : Symbol(T, Decl(inferTypes1.ts, 129, 7))
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>P : Symbol(P, Decl(inferTypes1.ts, 129, 34))
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>T : Symbol(T, Decl(inferTypes1.ts, 129, 7))
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>T : Symbol(T, Decl(inferTypes1.ts, 129, 7))
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type B<T> = string extends T ? { [P in T]: void; } : T; // Error
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>B : Symbol(B, Decl(inferTypes1.ts, 129, 55))
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>T : Symbol(T, Decl(inferTypes1.ts, 130, 7))
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>T : Symbol(T, Decl(inferTypes1.ts, 130, 7))
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>P : Symbol(P, Decl(inferTypes1.ts, 130, 34))
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>T : Symbol(T, Decl(inferTypes1.ts, 130, 7))
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>T : Symbol(T, Decl(inferTypes1.ts, 130, 7))
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‎tests/baselines/reference/inferTypes1.types‎

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Original file line numberDiff line numberDiff line change
@@ -558,3 +558,21 @@ type C2<S, U extends void> = S extends A2<infer T, U> ? [T, U] : never;
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>T : T
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>U : U
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// Repro from #21735
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type A<T> = T extends string ? { [P in T]: void; } : T;
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>A : A<T>
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>T : T
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>T : T
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>P : P
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>T : T
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>T : T
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type B<T> = string extends T ? { [P in T]: void; } : T; // Error
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>B : B<T>
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>T : T
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>T : T
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>P : P
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>T : T
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>T : T
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‎tests/cases/conformance/types/conditional/inferTypes1.ts‎

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Original file line numberDiff line numberDiff line change
@@ -127,3 +127,8 @@ type B1<S> = S extends A1<infer T, infer U> ? [T, U] : never;
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type A2<T, U extends void> = [T, U];
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type B2<S> = S extends A2<infer T, infer U> ? [T, U] : never;
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type C2<S, U extends void> = S extends A2<infer T, U> ? [T, U] : never;
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// Repro from #21735
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type A<T> = T extends string ? { [P in T]: void; } : T;
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type B<T> = string extends T ? { [P in T]: void; } : T; // Error

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