Fix missing concurrency check in [].forEach.

runtime/lib/array.dart

 // 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.
 
 
 // TODO(srdjan): Use shared array implementation.
 class _ObjectArray<E> implements List<E> {
 
   factory _ObjectArray(length) native "ObjectArray_allocate";
 
@@ skipping 49 matching lines @@
 
   Iterable<E> getRange(int start, [int end]) {
     return IterableMixinWorkaround.getRangeList(this, start, end);
   }
 
   // List interface.
   void setRange(int start, int end, Iterable<E> iterable, [int skipCount = 0]) {
     if (start < 0 || start > this.length) {
       throw new RangeError.range(start, 0, this.length);
     }
-    if (end < 0 || end > this.length) {
+    if (end < start || end > this.length) {
       throw new RangeError.range(end, start, this.length);
     }
     int length = end - start;
     if (length == 0) return;
 
     if (iterable is _ObjectArray) {
       _copyFromObjectArray(iterable, skipCount, start, length);
     } else {
       List otherList;
       int otherStart;
@@ skipping 462 matching lines @@
     }
     _position = _length;
     _current = null;
     return false;
   }
 
   E get current {
     return _current;
   }
 }