From 5e308b9b9a8fb8dfd777660687c255409dee0dff Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Tue, 12 Apr 2016 10:52:00 -0700
Subject: [PATCH] Fix the AV when accessing edge on IE debugger

---
 src/compiler/visitor.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index 81f36399b62..6acf8fcf17d 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -461,7 +461,7 @@ namespace ts {
         const edgeTraversalPath = nodeEdgeTraversalMap[node.kind];
         if (edgeTraversalPath) {
             for (const edge of edgeTraversalPath) {
-                const value = (<Map<any>>node)[edge.name];
+                const value = edge && (<Map<any>>node)[edge.name];
                 if (value !== undefined) {
                     result = isArray(value)
                         ? reduceLeft(<NodeArray<Node>>value, f, result)
@@ -619,7 +619,7 @@ namespace ts {
         const edgeTraversalPath = nodeEdgeTraversalMap[node.kind];
         if (edgeTraversalPath) {
             for (const edge of edgeTraversalPath) {
-                const value = <Node | NodeArray<Node>>node[edge.name];
+                const value = edge && <Node | NodeArray<Node>>node[edge.name];
                 if (value !== undefined) {
                     let visited: Node | NodeArray<Node>;
                     if (isArray(value)) {