From 0f6f8577020eaa13f245cb1baee66a81c802fa0e Mon Sep 17 00:00:00 2001 From: Anders Hejlsberg Date: Tue, 6 Jun 2017 11:38:50 -0700 Subject: [PATCH] Allow contextual signature to be generic --- src/compiler/checker.ts | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts index 5ad2ffeac6e..c32cb8d9acc 100644 --- a/src/compiler/checker.ts +++ b/src/compiler/checker.ts @@ -13042,13 +13042,13 @@ namespace ts { return node ? node.contextualMapper : identityMapper; } - // If the given type is an object or union type, if that type has a single signature, and if - // that signature is non-generic, return the signature. Otherwise return undefined. - function getNonGenericSignature(type: Type, node: FunctionExpression | ArrowFunction | MethodDeclaration): Signature { + // If the given type is an object or union type with a single signature, and if that signature has at + // least as many parameters as the given function, return the signature. Otherwise return undefined. + function getContextualCallSignature(type: Type, node: FunctionExpression | ArrowFunction | MethodDeclaration): Signature { const signatures = getSignaturesOfStructuredType(type, SignatureKind.Call); if (signatures.length === 1) { const signature = signatures[0]; - if (!signature.typeParameters && !isAritySmaller(signature, node)) { + if (!isAritySmaller(signature, node)) { return signature; } } @@ -13099,12 +13099,12 @@ namespace ts { return undefined; } if (!(type.flags & TypeFlags.Union)) { - return getNonGenericSignature(type, node); + return getContextualCallSignature(type, node); } let signatureList: Signature[]; const types = (type).types; for (const current of types) { - const signature = getNonGenericSignature(current, node); + const signature = getContextualCallSignature(current, node); if (signature) { if (!signatureList) { // This signature will contribute to contextual union signature