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disallow references to local variables of the function from parameter initializers

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This commit is contained in:
Vladimir Matveev
2016-05-06 12:01:38 -07:00
parent bc6d6ea49a
commit c36c074f37
11 changed files with 333 additions and 18 deletions
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62
src/compiler/checker.ts
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@@ -14174,28 +14174,54 @@ namespace ts {
const func = getContainingFunction(node);
visit(node.initializer);
function visit(n: Node) {
if (n.kind === SyntaxKind.Identifier) {
const referencedSymbol = getNodeLinks(n).resolvedSymbol;
function visit(n: Node): void {
if (isTypeNode(n) || isDeclarationName(n)) {
// do not dive in types
// skip declaration names (i.e. in object literal expressions)
return;
}
if (n.kind === SyntaxKind.PropertyAccessExpression) {
// skip property names in property access expression
return visit((<PropertyAccessExpression>n).expression);
}
else if (n.kind === SyntaxKind.Identifier) {
// check FunctionLikeDeclaration.locals (stores parameters\function local variable)
// if it contains entry with a specified name and if this entry matches the resolved symbol
if (referencedSymbol && referencedSymbol !== unknownSymbol && getSymbol(func.locals, referencedSymbol.name, SymbolFlags.Value) === referencedSymbol) {
if (referencedSymbol.valueDeclaration.kind === SyntaxKind.Parameter) {
if (referencedSymbol.valueDeclaration === node) {
error(n, Diagnostics.Parameter_0_cannot_be_referenced_in_its_initializer, declarationNameToString(node.name));
return;
}
if (referencedSymbol.valueDeclaration.pos < node.pos) {
// legal case - parameter initializer references some parameter strictly on left of current parameter declaration
return;
}
// fall through to error reporting
}
error(n, Diagnostics.Initializer_of_parameter_0_cannot_reference_identifier_1_declared_after_it, declarationNameToString(node.name), declarationNameToString(<Identifier>n));
// if it contains entry with a specified name
const symbol = getSymbol(func.locals, (<Identifier>n).text, SymbolFlags.Value);
if (!symbol || symbol === unknownSymbol) {
return;
}
if (symbol.valueDeclaration === node) {
error(n, Diagnostics.Parameter_0_cannot_be_referenced_in_its_initializer, declarationNameToString(node.name));
return;
}
if (symbol.valueDeclaration.kind === SyntaxKind.Parameter) {
// it is ok to reference parameter in initializer if either
// - parameter is located strictly on the left of current parameter declaration
if (symbol.valueDeclaration.pos < node.pos) {
return;
}
// - parameter is wrapped in function-like entity
let current = n;
while (current !== node.initializer) {
if (isFunctionLike(current.parent)) {
return;
}
// computed property names/initializers in instance property declaration of class like entities
// are executed in constructor and thus deferred
if (current.parent.kind === SyntaxKind.PropertyDeclaration &&
!(current.parent.flags & NodeFlags.Static) &&
isClassLike(current.parent.parent)) {
return;
}
current = current.parent;
}
// fall through to report error
}
error(n, Diagnostics.Initializer_of_parameter_0_cannot_reference_identifier_1_declared_after_it, declarationNameToString(node.name), declarationNameToString(<Identifier>n));
}
else {
forEachChild(n, visit);
return forEachChild(n, visit);
}
}
}