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Vladimir Matveev
2015-03-11 23:49:35 -07:00
parent 751b1aee16
commit d3246a340a
4 changed files with 72 additions and 40 deletions
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79
src/compiler/checker.ts
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@@ -435,53 +435,60 @@ module ts {
return undefined;
}
if (result.flags & SymbolFlags.BlockScopedVariable) {
// Block-scoped variables cannot be used before their definition
var declaration = forEach(result.declarations, d => isBlockOrCatchScoped(d) ? d : undefined);
Debug.assert(declaration !== undefined, "Block-scoped variable declaration is undefined");
// first check if usage is lexically located after the declaration
var isUsedBeforeDeclaration = !isDefinedBefore(declaration, errorLocation);
if (!isUsedBeforeDeclaration) {
// lexical check succedded however code still can be illegal.
// - block scoped variables cannot be used in its initializers
// let x = x; // illegal but usage is lexically after definition
// - in ForIn/ForOf statements variable cannot be contained in expression part
// for (let x in x)
// for (let x of x)
// climb up to the variable declaration skipping binding patterns
var variableDeclaration = <VariableDeclaration>getAncestor(declaration, SyntaxKind.VariableDeclaration);
var container = getEnclosingBlockScopeContainer(variableDeclaration);
if (variableDeclaration.parent.parent.kind === SyntaxKind.VariableStatement ||
variableDeclaration.parent.parent.kind === SyntaxKind.ForStatement) {
// variable statement/for statement case, use site should not be inside initializer
isUsedBeforeDeclaration = isChildNode(errorLocation, variableDeclaration.initializer, container);
}
else if (variableDeclaration.parent.parent.kind === SyntaxKind.ForOfStatement ||
variableDeclaration.parent.parent.kind === SyntaxKind.ForInStatement) {
// ForIn/ForOf case - use site should not be used in expression part
isUsedBeforeDeclaration = isChildNode(errorLocation, (<ForInStatement>variableDeclaration.parent.parent).expression, container);
}
}
if (isUsedBeforeDeclaration) {
error(errorLocation, Diagnostics.Block_scoped_variable_0_used_before_its_declaration, declarationNameToString(declaration.name));
}
checkResolvedBlockScopedVariable(result, errorLocation);
}
}
return result;
}
function checkResolvedBlockScopedVariable(result: Symbol, errorLocation: Node): void {
Debug.assert((result.flags & SymbolFlags.BlockScopedVariable) !== 0)
// Block-scoped variables cannot be used before their definition
var declaration = forEach(result.declarations, d => isBlockOrCatchScoped(d) ? d : undefined);
Debug.assert(declaration !== undefined, "Block-scoped variable declaration is undefined");
// first check if usage is lexically located after the declaration
var isUsedBeforeDeclaration = !isDefinedBefore(declaration, errorLocation);
if (!isUsedBeforeDeclaration) {
// lexical check succeeded however code still can be illegal.
// - block scoped variables cannot be used in its initializers
// let x = x; // illegal but usage is lexically after definition
// - in ForIn/ForOf statements variable cannot be contained in expression part
// for (let x in x)
// for (let x of x)
// climb up to the variable declaration skipping binding patterns
var variableDeclaration = <VariableDeclaration>getAncestor(declaration, SyntaxKind.VariableDeclaration);
var container = getEnclosingBlockScopeContainer(variableDeclaration);
if (variableDeclaration.parent.parent.kind === SyntaxKind.VariableStatement ||
variableDeclaration.parent.parent.kind === SyntaxKind.ForStatement) {
// variable statement/for statement case,
// use site should not be inside variable declaration (initializer of declaration or binding element)
isUsedBeforeDeclaration = isDescendentOf(errorLocation, variableDeclaration, container);
}
else if (variableDeclaration.parent.parent.kind === SyntaxKind.ForOfStatement ||
variableDeclaration.parent.parent.kind === SyntaxKind.ForInStatement) {
// ForIn/ForOf case - use site should not be used in expression part
var expression = (<ForInStatement>variableDeclaration.parent.parent).expression;
isUsedBeforeDeclaration = isDescendentOf(errorLocation, expression, container);
}
}
if (isUsedBeforeDeclaration) {
error(errorLocation, Diagnostics.Block_scoped_variable_0_used_before_its_declaration, declarationNameToString(declaration.name));
}
}
/* Starting from 'initial' node walk up the parent chain until 'stopAt' node is reached.
* If at any point current node is equal to 'parent' node - return true.
* Return false if 'stopAt' node is reached.
* Return false if 'stopAt' node is reached or isFunctionLike(current) === true.
*/
function isChildNode(initial: Node, parent: Node, stopAt: Node): boolean {
function isDescendentOf(initial: Node, parent: Node, stopAt: Node): boolean {
if (!parent) {
return false;
}
for (var current = initial; current && current !== stopAt; current = current.parent) {
for (var current = initial; current && current !== stopAt && !isFunctionLike(current); current = current.parent) {
if (current === parent) {
return true;
}