microsoft/TypeScript
1
0
Fork 0
mirror of https://github.com/microsoft/TypeScript.git synced 2026-02-05 08:11:30 -06:00
Code Issues Packages Projects Releases 212 Wiki Activity

do not emit default initializer for let\const in for-in\for-of statements

Browse Source
This commit is contained in:
Vladimir Matveev 2015-02-25 17:44:09 -08:00
parent 8891128426
commit 33dfe5068a
2 changed files with 25 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/compiler/checker.ts
View File

@ -5119,9 +5119,9 @@ module ts {
while (current && !isNameScopeBoundary(current)) {
if (isIterationStatement(current, /*lookInLabeledStatements*/ false)) {
if (inFunction) {
getNodeLinks(current).flags |= NodeCheckFlags.BlockScopedBindingInLoop;
grammarErrorOnFirstToken(current, Diagnostics.Code_in_the_loop_captures_block_scoped_variable_0_in_closure_This_is_natively_supported_in_ECMAScript_6_or_higher, declarationNameToString(node));
}
// mark value declaration so during emit they can have a special handling
getNodeLinks(<VariableDeclaration>symbol.valueDeclaration).flags |= NodeCheckFlags.BlockScopedBindingInLoop;
break;
}

40
src/compiler/emitter.ts
View File

@ -1702,6 +1702,7 @@ module ts {
function makeUniqueName(location: Node, baseName: string): string {
var name: string
// first try to check if base name can be used as is
if (!isExistingName(location, baseName)) {
name = baseName;
}
@ -1721,12 +1722,9 @@ module ts {
return currentScopeNames[name] = name;
}
function isGeneratedName(name: string): boolean {
return currentScopeNames && hasProperty(currentScopeNames, name);
}
function isExistingName(location: Node, name: string) {
return !resolver.isUnknownIdentifier(location, name) || isGeneratedName(name);
return !resolver.isUnknownIdentifier(location, name) ||
(currentScopeNames && hasProperty(currentScopeNames, name));
}
function initializeEmitterWithSourceMaps() {
@ -3559,7 +3557,6 @@ module ts {
result.expression = zero;
return result;
}
function emitExportMemberAssignments(name: Identifier) {
if (exportSpecifiers && hasProperty(exportSpecifiers, name.text)) {
@ -3802,18 +3799,24 @@ module ts {
emitModuleMemberName(node);
var initializer = node.initializer;
if (!initializer) {
if (!initializer && languageVersion < ScriptTarget.ES6) {
// downlevel emit for non-initialized let bindings defined in loops
// for (...) { let x; }
// should be
// for (...) { var <some-uniqie-name> = void 0; }
// this is necessary to preserve ES6 semantic in scenarios like
// for (...) { let x; console.log(x); x = 1 } // assignment on one iteration should not affect other iterations
var initializer =
languageVersion < ScriptTarget.ES6 &&
var isUninitializedLet =
(resolver.getNodeCheckFlags(node) & NodeCheckFlags.BlockScopedBindingInLoop) &&
(getCombinedFlagsForIdentifier(<Identifier>node.name) & NodeFlags.Let) &&
createVoidZero();
(getCombinedFlagsForIdentifier(<Identifier>node.name) & NodeFlags.Let);
// NOTE: default initialization should not be added to let bindings in for-in\for-of statements
if (isUninitializedLet &&
node.parent.parent.kind !== SyntaxKind.ForInStatement &&
node.parent.parent.kind !== SyntaxKind.ForOfStatement) {
initializer = createVoidZero();
}
}
emitOptional(" = ", initializer);
@ -3834,20 +3837,20 @@ module ts {
var current = node;
while (current) {
if (isAnyFunction(current)) {
return current.parent;
return current;
}
switch (current.kind) {
case SyntaxKind.CatchClause:
case SyntaxKind.ForStatement:
case SyntaxKind.ForInStatement:
case SyntaxKind.SwitchKeyword:
return current.parent;
return current;
case SyntaxKind.Block:
if (isAnyFunction(current.parent)) {
return current.parent.parent;
return current.parent;
}
else {
return current.parent;
return current;
}
case SyntaxKind.SourceFile:
return current;
@ -3893,7 +3896,12 @@ module ts {
return;
}
var generatedName = makeUniqueName(getEnclosingBlockScopeContainer(node), (<Identifier>node).text);
var blockScopeContainer = getEnclosingBlockScopeContainer(node);
var parent = blockScopeContainer.kind === SyntaxKind.SourceFile
? blockScopeContainer
: blockScopeContainer.parent;
var generatedName = makeUniqueName(parent, (<Identifier>node).text);
var variableId = resolver.getBlockScopedVariableId(<Identifier>node);
if (!generatedBlockScopeNames) {
generatedBlockScopeNames = [];