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Properly propagate contextual types into parameter destructuring elements

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This commit is contained in:
Anders Hejlsberg 2015-09-24 13:35:12 -07:00
parent a292da593b
commit 1a26789615
1 changed files with 14 additions and 0 deletions
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14
src/compiler/checker.ts
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@ -9169,10 +9169,24 @@ namespace ts {
}
}
// When contextual typing assigns a type to a parameter that contains a binding pattern, we also need to push
// the destructured type into the contained binding elements.
function assignBindingElementTypes(node: VariableLikeDeclaration) {
if (isBindingPattern(node.name)) {
for (let element of (<BindingPattern>node.name).elements) {
if (element.kind !== SyntaxKind.OmittedExpression) {
getSymbolLinks(getSymbolOfNode(element)).type = getTypeForBindingElement(element);
assignBindingElementTypes(element);
}
}
}
}
function assignTypeToParameterAndFixTypeParameters(parameter: Symbol, contextualType: Type, mapper: TypeMapper) {
let links = getSymbolLinks(parameter);
if (!links.type) {
links.type = instantiateType(contextualType, mapper);
assignBindingElementTypes(<ParameterDeclaration>parameter.valueDeclaration);
}
else if (isInferentialContext(mapper)) {
// Even if the parameter already has a type, it might be because it was given a type while