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Commit 8d58c8d

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weswighamweswigham
authored
Base signatures resolve only the type parameters local to the signature, not all type parameters (microsoft#42703)
1 parent 6da2625 commit 8d58c8d
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6 files changed

+49-2Lines changed: 49 additions & 2 deletions
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‎src/compiler/checker.ts‎

Copy file name to clipboardExpand all lines: src/compiler/checker.ts
+13-2Lines changed: 13 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -12244,9 +12244,20 @@ namespace ts {
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function getBaseSignature(signature: Signature) {
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const typeParameters = signature.typeParameters;
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if (typeParameters) {
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if (signature.baseSignatureCache) {
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return signature.baseSignatureCache;
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}
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const typeEraser = createTypeEraser(typeParameters);
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const baseConstraints = map(typeParameters, tp => instantiateType(getBaseConstraintOfType(tp), typeEraser) || unknownType);
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return instantiateSignature(signature, createTypeMapper(typeParameters, baseConstraints), /*eraseTypeParameters*/ true);
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const baseConstraintMapper = createTypeMapper(typeParameters, map(typeParameters, tp => getConstraintOfTypeParameter(tp) || unknownType));
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let baseConstraints: readonly Type[] = map(typeParameters, tp => instantiateType(tp, baseConstraintMapper) || unknownType);
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// Run N type params thru the immediate constraint mapper up to N times
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// This way any noncircular interdependent type parameters are definitely resolved to their external dependencies
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for (let i = 0; i < typeParameters.length - 1; i++) {
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baseConstraints = instantiateTypes(baseConstraints, baseConstraintMapper);
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}
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// and then apply a type eraser to remove any remaining circularly dependent type parameters
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baseConstraints = instantiateTypes(baseConstraints, typeEraser);
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return signature.baseSignatureCache = instantiateSignature(signature, createTypeMapper(typeParameters, baseConstraints), /*eraseTypeParameters*/ true);
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}
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return signature;
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}
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‎src/compiler/types.ts‎

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+2Lines changed: 2 additions & 0 deletions
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@@ -5550,6 +5550,8 @@ namespace ts {
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/* @internal */
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canonicalSignatureCache?: Signature; // Canonical version of signature (deferred)
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/* @internal */
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baseSignatureCache?: Signature; // Base version of signature (deferred)
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/* @internal */
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optionalCallSignatureCache?: { inner?: Signature, outer?: Signature }; // Optional chained call version of signature (deferred)
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/* @internal */
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isolatedSignatureType?: ObjectType; // A manufactured type that just contains the signature for purposes of signature comparison
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‎tests/baselines/reference/conditionalTypeGenericInSignatureTypeParameterConstraint.js‎

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+7Lines changed: 7 additions & 0 deletions
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@@ -0,0 +1,7 @@
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//// [conditionalTypeGenericInSignatureTypeParameterConstraint.ts]
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// should be x
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type H_inline1<x> = (<o extends x>() => o) extends (() => infer o) ? o : never;
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type Result = H_inline1<string>; // should be `string`
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//// [conditionalTypeGenericInSignatureTypeParameterConstraint.js]
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‎tests/baselines/reference/conditionalTypeGenericInSignatureTypeParameterConstraint.symbols‎

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+15Lines changed: 15 additions & 0 deletions
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@@ -0,0 +1,15 @@
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=== tests/cases/compiler/conditionalTypeGenericInSignatureTypeParameterConstraint.ts ===
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// should be x
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type H_inline1<x> = (<o extends x>() => o) extends (() => infer o) ? o : never;
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>H_inline1 : Symbol(H_inline1, Decl(conditionalTypeGenericInSignatureTypeParameterConstraint.ts, 0, 0))
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>x : Symbol(x, Decl(conditionalTypeGenericInSignatureTypeParameterConstraint.ts, 1, 15))
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>o : Symbol(o, Decl(conditionalTypeGenericInSignatureTypeParameterConstraint.ts, 1, 22))
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>x : Symbol(x, Decl(conditionalTypeGenericInSignatureTypeParameterConstraint.ts, 1, 15))
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>o : Symbol(o, Decl(conditionalTypeGenericInSignatureTypeParameterConstraint.ts, 1, 22))
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>o : Symbol(o, Decl(conditionalTypeGenericInSignatureTypeParameterConstraint.ts, 1, 63))
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>o : Symbol(o, Decl(conditionalTypeGenericInSignatureTypeParameterConstraint.ts, 1, 63))
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type Result = H_inline1<string>; // should be `string`
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>Result : Symbol(Result, Decl(conditionalTypeGenericInSignatureTypeParameterConstraint.ts, 1, 79))
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>H_inline1 : Symbol(H_inline1, Decl(conditionalTypeGenericInSignatureTypeParameterConstraint.ts, 0, 0))
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‎tests/baselines/reference/conditionalTypeGenericInSignatureTypeParameterConstraint.types‎

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+8Lines changed: 8 additions & 0 deletions
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@@ -0,0 +1,8 @@
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=== tests/cases/compiler/conditionalTypeGenericInSignatureTypeParameterConstraint.ts ===
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// should be x
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type H_inline1<x> = (<o extends x>() => o) extends (() => infer o) ? o : never;
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>H_inline1 : x
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type Result = H_inline1<string>; // should be `string`
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>Result : string
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‎tests/cases/compiler/conditionalTypeGenericInSignatureTypeParameterConstraint.ts‎

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+4Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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// should be x
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type H_inline1<x> = (<o extends x>() => o) extends (() => infer o) ? o : never;
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type Result = H_inline1<string>; // should be `string`

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