Addresses CR comment

tinganho · tinganho · commit d5c24f3cd3bd · 2017-08-02T20:13:43.000+02:00
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
@@ -2134,7 +2134,7 @@ namespace ts {
             if (node.variableDeclaration) {
                 writeToken(SyntaxKind.OpenParenToken, openParenPos);
                 emit(node.variableDeclaration);
-                writeToken(SyntaxKind.CloseParenToken, node.variableDeclaration ? node.variableDeclaration.end : openParenPos);
+                writeToken(SyntaxKind.CloseParenToken, node.variableDeclaration.end);
                 write(" ");
             }
             emit(node.block);
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
@@ -2128,14 +2128,14 @@ namespace ts {
             : node;
     }
 
-    export function createCatchClause(variableDeclaration: string | VariableDeclaration, block: Block) {
+    export function createCatchClause(variableDeclaration: string | VariableDeclaration | undefined, block: Block) {
         const node = <CatchClause>createSynthesizedNode(SyntaxKind.CatchClause);
         node.variableDeclaration = typeof variableDeclaration === "string" ? createVariableDeclaration(variableDeclaration) : variableDeclaration;
         node.block = block;
         return node;
     }
 
-    export function updateCatchClause(node: CatchClause, variableDeclaration: VariableDeclaration, block: Block) {
+    export function updateCatchClause(node: CatchClause, variableDeclaration: VariableDeclaration | undefined, block: Block) {
         return node.variableDeclaration !== variableDeclaration
             || node.block !== block
             ? updateNode(createCatchClause(variableDeclaration, block), node)
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
@@ -4783,6 +4783,10 @@ namespace ts {
                 result.variableDeclaration = parseVariableDeclaration();
                 parseExpected(SyntaxKind.CloseParenToken);
             }
+            else {
+                // Keep shape of node to not avoid degrading performance.
+                result.variableDeclaration = undefined;
+            }
 
             result.block = parseBlock(/*ignoreMissingOpenBrace*/ false);
             return finishNode(result);
diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
@@ -3173,7 +3173,7 @@ namespace ts {
         function visitCatchClause(node: CatchClause): CatchClause {
             const ancestorFacts = enterSubtree(HierarchyFacts.BlockScopeExcludes, HierarchyFacts.BlockScopeIncludes);
             let updated: CatchClause;
-            Debug.assert(!!node.variableDeclaration, "Catch clauses should always be present when downleveling ES2015 code.");
+            Debug.assert(!!node.variableDeclaration, "Catch clause variable should always be present when downleveling ES2015.");
             if (isBindingPattern(node.variableDeclaration.name)) {
                 const temp = createTempVariable(/*recordTempVariable*/ undefined);
                 const newVariableDeclaration = createVariableDeclaration(temp);
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
@@ -1807,7 +1807,7 @@ namespace ts {
 
     export interface CatchClause extends Node {
         kind: SyntaxKind.CatchClause;
-        parent?: TryStatement; // We make this optional to parse missing try statements
+        parent?: TryStatement;
         variableDeclaration?: VariableDeclaration;
         block: Block;
     }

Original file line number	Diff line number	Diff line change
`@@ -2134,7 +2134,7 @@ namespace ts {`
`2134`	`2134`	`if (node.variableDeclaration) {`
`2135`	`2135`	`writeToken(SyntaxKind.OpenParenToken, openParenPos);`
`2136`	`2136`	`emit(node.variableDeclaration);`
`2137`		`- writeToken(SyntaxKind.CloseParenToken, node.variableDeclaration ? node.variableDeclaration.end : openParenPos);`
	`2137`	`+ writeToken(SyntaxKind.CloseParenToken, node.variableDeclaration.end);`
`2138`	`2138`	`write(" ");`
`2139`	`2139`	`}`
`2140`	`2140`	`emit(node.block);`
Original file line number	Diff line number	Diff line change
`@@ -1807,7 +1807,7 @@ namespace ts {`
`1807`	`1807`
`1808`	`1808`	`export interface CatchClause extends Node {`
`1809`	`1809`	`kind: SyntaxKind.CatchClause;`
`1810`		`- parent?: TryStatement; // We make this optional to parse missing try statements`
	`1810`	`+ parent?: TryStatement;`
`1811`	`1811`	`variableDeclaration?: VariableDeclaration;`
`1812`	`1812`	`block: Block;`
`1813`	`1813`	`}`