Issue 3931. Visit children nodes safely.

compiler/java/com/google/dart/compiler/ast/DartArrayAccess.java

Index: compiler/java/com/google/dart/compiler/ast/DartArrayAccess.java
diff --git a/compiler/java/com/google/dart/compiler/ast/DartArrayAccess.java b/compiler/java/com/google/dart/compiler/ast/DartArrayAccess.java
index 03eccb6abce438ee23599ffa648b68e1b97174d3..f861284c536fe24dfc7eaec1b528893cf993748a 100644
--- a/compiler/java/com/google/dart/compiler/ast/DartArrayAccess.java
+++ b/compiler/java/com/google/dart/compiler/ast/DartArrayAccess.java
@@ -1,4 +1,4 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
@@ -46,8 +46,8 @@ public class DartArrayAccess extends DartExpression {
 
   @Override
   public void visitChildren(ASTVisitor<?> visitor) {
-    target.accept(visitor);
-    key.accept(visitor);
+    safelyVisitChild(target, visitor);
+    safelyVisitChild(key, visitor);
   }
 
   @Override