Compile time error if name is used before variable is declared

runtime/lib/growable_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.
 
 class _GrowableList<T> implements List<T> {
   static final int _classId = (new _GrowableList(0))._cid;
 
   void insert(int index, T element) {
     if (index < 0 || index > length) {
       throw new RangeError.range(index, 0, length);
@@ skipping 96 matching lines @@
   void replaceRange(int start, int end, Iterable<T> iterable) {
     IterableMixinWorkaround.replaceRangeList(this, start, end, iterable);
   }
 
   void fillRange(int start, int end, [T fillValue]) {
     IterableMixinWorkaround.fillRangeList(this, start, end, fillValue);
   }
 
   List<T> sublist(int start, [int end]) {
     Arrays.indicesCheck(this, start, end);
-    if (end == null) end = length;
+    if (end == null) end = this.length;
     int length = end - start;
     if (start == end) return <T>[];
     List list = new _GrowableList<T>.withCapacity(length);
     list.length = length;
     Arrays.copy(this, start, list, 0, length);
     return list;
   }
 
   factory _GrowableList(int length) {
     var data = new _List((length == 0) ? 4 : length);
@@ skipping 225 matching lines @@
   }
 
   Set<T> toSet() {
     return new Set<T>.from(this);
   }
 
   Map<int, T> asMap() {
     return IterableMixinWorkaround.asMapList(this);
   }
 }