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Support for-in both with and without variable declaration

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This commit is contained in:
Anders Hejlsberg
2016-01-06 16:12:49 -08:00
parent 9ce5e6477b
commit 120569afb0
1 changed files with 33 additions and 7 deletions
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40
src/compiler/checker.ts
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@@ -8564,17 +8564,43 @@ namespace ts {
}
/**
* Return true if given node is an expression consisting of an identifier (possibly parenthesized)
* that references a variable declared in a for-in statement for an array-like object.
* Return the symbol of the for-in variable declared or referenced by the given for-in statement.
*/
function isForInVariableForArrayLikeObject(node: Expression) {
const e = skipParenthesizedNodes(node);
function getForInVariableSymbol(node: ForInStatement): Symbol {
const initializer = node.initializer;
if (initializer.kind === SyntaxKind.VariableDeclarationList) {
const variable = (<VariableDeclarationList>initializer).declarations[0];
if (variable && !isBindingPattern(variable.name)) {
return getSymbolOfNode(variable);
}
}
else if (initializer.kind === SyntaxKind.Identifier) {
return getResolvedSymbol(<Identifier>initializer);
}
return undefined;
}
/**
* Return true if given node is an expression consisting of an identifier (possibly parenthesized)
* that references a variable declared in a containing for-in statement for an array-like object.
*/
function isForInVariableForArrayLikeObject(expr: Expression) {
const e = skipParenthesizedNodes(expr);
if (e.kind === SyntaxKind.Identifier) {
const symbol = getResolvedSymbol(<Identifier>e);
if (symbol.flags & SymbolFlags.Variable) {
const parent = symbol.valueDeclaration.parent.parent;
return parent.kind === SyntaxKind.ForInStatement &&
isArrayLikeType(checkExpression((<ForInStatement>parent).expression));
let child: Node = expr;
let node = expr.parent;
while (node) {
if (node.kind === SyntaxKind.ForInStatement &&
child === (<ForInStatement>node).statement &&
getForInVariableSymbol(<ForInStatement>node) === symbol &&
isArrayLikeType(checkExpression((<ForInStatement>node).expression))) {
return true;
}
child = node;
node = node.parent;
}
}
}
return false;