Issue 3931. Visit children nodes safely.

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

Index: compiler/java/com/google/dart/compiler/ast/DartTypeExpression.java
diff --git a/compiler/java/com/google/dart/compiler/ast/DartTypeExpression.java b/compiler/java/com/google/dart/compiler/ast/DartTypeExpression.java
index 8ec9dd19695dd0fd92fedd43756fbe3ea605493d..9d2a22a2d95ba47debce4e018d7e6f08ec0929f2 100644
--- a/compiler/java/com/google/dart/compiler/ast/DartTypeExpression.java
+++ b/compiler/java/com/google/dart/compiler/ast/DartTypeExpression.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.
 
@@ -21,7 +21,7 @@ public class DartTypeExpression extends DartExpression {
 
   @Override
   public void visitChildren(ASTVisitor<?> visitor) {
-    typeNode.accept(visitor);
+    safelyVisitChild(typeNode, visitor);
   }
 
   @Override