Refactor removeRange.

sdk/lib/collection/list.dart

 // Copyright (c) 2013, 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.
 
 part of dart.collection;
 
 /**
  * Abstract implementation of a list.
  *
  * All operations are defined in terms of `length`, `operator[]`,
@@ skipping 371 matching lines @@
     int moveLength = oldLength - start;
     this.length += length;
     if (moveLength > 0) {
       this.setRange(start + length, oldLength, this, start);
     }
     for (int i = 0; i < length; i++) {
       this[start + i] = initialValue;
     }
   }
 
-  void removeRange(int start, int length) {
+  void removeRange(int start, int end) {
     if (start < 0 || start > this.length) {
       throw new RangeError.range(start, 0, this.length);
     }
-    if (length < 0 || start + length > this.length) {
-      throw new RangeError.range(length, 0, this.length - start);
+    if (end < start || end > this.length) {
+      throw new RangeError.range(end, start, this.length);
     }
-    int end = start + length;
+    int length = end - start;
     setRange(start, this.length - length, this, end);
     this.length -= length;
   }
 
   void clearRange(int start, int length, [E fill]) {
     for (int i = 0; i < length; i++) {
       this[start + i] = fill;
     }
   }
 
@@ skipping 57 matching lines @@
     for (int i = startIndex; i >= 0; i--) {
       if (this[i] == element) {
         return i;
       }
     }
     return -1;
   }
 
   Iterable<E> get reversed => new ReversedListIterable(this);
 }