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Use contextual type of object literal as 'this' in methods

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This commit is contained in:
Anders Hejlsberg 2017-02-24 18:00:27 -08:00
parent 9b6b6cc289
commit 9dc2bae2e6
1 changed files with 15 additions and 14 deletions
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29
src/compiler/checker.ts
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@ -11512,25 +11512,26 @@ namespace ts {
const containingLiteral = getContainingObjectLiteral(func);
if (containingLiteral) {
// We have an object literal method. Check if the containing object literal has a contextual type
// and if that contextual type is or includes a ThisType<T>. If so, T is the contextual type for
// 'this'. We continue looking in any directly enclosing object literals.
let objectLiteral = containingLiteral;
while (true) {
const type = getApparentTypeOfContextualType(objectLiteral);
if (type) {
const thisType = getThisTypeFromContextualType(type);
if (thisType) {
return thisType;
}
// that includes a ThisType<T>. If so, T is the contextual type for 'this'. We continue looking in
// any directly enclosing object literals.
const contextualType = getApparentTypeOfContextualType(containingLiteral);
let literal = containingLiteral;
let type = contextualType;
while (type) {
const thisType = getThisTypeFromContextualType(type);
if (thisType) {
return thisType;
}
if (objectLiteral.parent.kind !== SyntaxKind.PropertyAssignment) {
if (literal.parent.kind !== SyntaxKind.PropertyAssignment) {
break;
}
objectLiteral = <ObjectLiteralExpression>objectLiteral.parent.parent;
literal = <ObjectLiteralExpression>literal.parent.parent;
type = getApparentTypeOfContextualType(literal);
}
// There was no contextual ThisType<T> for the containing object literal, so the contextual type
// for 'this' is the type of the object literal itself.
return checkExpressionCached(containingLiteral);
// for 'this' is the contextual type for the containing object literal or the type of the object
// literal itself.
return contextualType || checkExpressionCached(containingLiteral);
}
// In an assignment of the form 'obj.xxx = function(...)' or 'obj[xxx] = function(...)', the
// contextual type for 'this' is 'obj'.