anchor.diff:  
     bool moveNext() {
       if (_list.length != _originalLength) {
  -      throw new ConcurrentModificationError(list);
  +      throw new ConcurrentModificationError(_list);
       }
       if (_index <= _start) return false;
       _index -= 1;
  
positive.code:  */
  abstract class FixedLengthListBase<E> extends ListBase<E> {
    void operator[]=(int index, E value);
  
    List<E> get reversed => new ReversedListView<E>(this, 0, null);
  
    void sort([Comparator<E> compare]) {
      Sort.sort(this, compare);
  
negative.code:   }
  
    String toString() => ToString.collectionToString(this);
  
    List<E> get reversed {
      return new ReversedListView(this, 0, null);
    }
  }
  
  /**
  