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Only methods and constructors are bivariant in --strictFunctionTypes mode

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This commit is contained in:
Anders Hejlsberg
2017-09-28 14:33:35 -07:00
parent 1795614c41
commit 5613be4907
1 changed files with 5 additions and 14 deletions
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19
src/compiler/checker.ts
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@@ -3549,7 +3549,7 @@ namespace ts {
return;
}
if (resolved.callSignatures.length === 1 && !resolved.constructSignatures.length && isStrictSignature(resolved.callSignatures[0])) {
if (resolved.callSignatures.length === 1 && !resolved.constructSignatures.length) {
const parenthesizeSignature = shouldAddParenthesisAroundFunctionType(resolved.callSignatures[0], flags);
if (parenthesizeSignature) {
writePunctuation(writer, SyntaxKind.OpenParenToken);
@@ -3560,7 +3560,7 @@ namespace ts {
}
return;
}
if (resolved.constructSignatures.length === 1 && !resolved.callSignatures.length && isStrictSignature(resolved.constructSignatures[0])) {
if (resolved.constructSignatures.length === 1 && !resolved.callSignatures.length) {
if (flags & TypeFormatFlags.InElementType) {
writePunctuation(writer, SyntaxKind.OpenParenToken);
}
@@ -8522,17 +8522,6 @@ namespace ts {
/*errorReporter*/ undefined, compareTypesAssignable) !== Ternary.False;
}
// A signature is considered strict if it is declared in a function type literal, a constructor type
// literal, a function expression, an arrow function, or a function declaration with no overloads. A
// strict signature is subject to strict checking in strictFunctionTypes mode.
function isStrictSignature(signature: Signature) {
const declaration = signature.declaration;
const kind = declaration ? declaration.kind : SyntaxKind.Unknown;
return kind === SyntaxKind.FunctionType || kind === SyntaxKind.ConstructorType ||
kind === SyntaxKind.FunctionExpression || kind === SyntaxKind.ArrowFunction ||
(kind === SyntaxKind.FunctionDeclaration && getSingleCallSignature(getTypeOfSymbol(getSymbolOfNode(declaration))));
}
type ErrorReporter = (message: DiagnosticMessage, arg0?: string, arg1?: string) => void;
/**
@@ -8558,7 +8547,9 @@ namespace ts {
source = instantiateSignatureInContextOf(source, target, /*contextualMapper*/ undefined, compareTypes);
}
const strictVariance = strictFunctionTypes && isStrictSignature(target);
const kind = target.declaration ? target.declaration.kind : SyntaxKind.Unknown;
const strictVariance = strictFunctionTypes && kind !== SyntaxKind.MethodDeclaration &&
kind !== SyntaxKind.MethodSignature && kind !== SyntaxKind.Constructor;
let result = Ternary.True;
const sourceThisType = getThisTypeOfSignature(source);