Do not pass context flags downward while parsing binding elements.

CyrusNajmabadi · CyrusNajmabadi · commit 30f9a5ca2adb · 2014-12-15T21:41:02.000-08:00
This prevents an unnecessary allocation, simplifies parsing code, and prevents
an issue where parsing depends on context flags not stored in the final tree.
This is an issue for incremental parsing that can lead to nodes being reused
inappropriately.
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
@@ -3277,46 +3277,47 @@ module ts {
 
         // DECLARATIONS
 
-        function parseBindingElement(context: ParsingContext): BindingElement {
-            if (context === ParsingContext.ArrayBindingElements && token === SyntaxKind.CommaToken) {
+        function parseArrayBindingElement(): BindingElement {
+            if (token === SyntaxKind.CommaToken) {
                 return <BindingElement>createNode(SyntaxKind.OmittedExpression);
             }
+
             var node = <BindingElement>createNode(SyntaxKind.BindingElement);
-            if (context === ParsingContext.ObjectBindingElements) {
-                // TODO(andersh): Handle computed properties
-                var id = parsePropertyName();
-                if (id.kind === SyntaxKind.Identifier && token !== SyntaxKind.ColonToken) {
-                    node.name = <Identifier>id;
-                }
-                else {
-                    parseExpected(SyntaxKind.ColonToken);
-                    node.propertyName = <Identifier>id;
-                    node.name = parseIdentifierOrPattern();
-                }
+            node.name = parseIdentifierOrPattern();
+            node.initializer = parseInitializer(/*inParameter*/ false);
+            return finishNode(node);
+        }
+
+        function parseObjectBindingElement(): BindingElement {
+            var node = <BindingElement>createNode(SyntaxKind.BindingElement);
+
+            // TODO(andersh): Handle computed properties
+            var id = parsePropertyName();
+            if (id.kind === SyntaxKind.Identifier && token !== SyntaxKind.ColonToken) {
+                node.name = <Identifier>id;
             }
             else {
+                parseExpected(SyntaxKind.ColonToken);
+                node.propertyName = <Identifier>id;
                 node.name = parseIdentifierOrPattern();
             }
+
             node.initializer = parseInitializer(/*inParameter*/ false);
             return finishNode(node);
         }
 
-        function parseBindingList(context: ParsingContext): NodeArray<BindingElement> {
-            return parseDelimitedList(context, () => parseBindingElement(context));
-        }
-
         function parseObjectBindingPattern(): BindingPattern {
             var node = <BindingPattern>createNode(SyntaxKind.ObjectBindingPattern);
             parseExpected(SyntaxKind.OpenBraceToken);
-            node.elements = parseBindingList(ParsingContext.ObjectBindingElements);
+            node.elements = parseDelimitedList(ParsingContext.ObjectBindingElements, parseObjectBindingElement);
             parseExpected(SyntaxKind.CloseBraceToken);
             return finishNode(node);
         }
 
         function parseArrayBindingPattern(): BindingPattern {
             var node = <BindingPattern>createNode(SyntaxKind.ArrayBindingPattern);
             parseExpected(SyntaxKind.OpenBracketToken);
-            node.elements = parseBindingList(ParsingContext.ArrayBindingElements);
+            node.elements = parseDelimitedList(ParsingContext.ArrayBindingElements, parseArrayBindingElement);
             parseExpected(SyntaxKind.CloseBracketToken);
             return finishNode(node);
         }
