anchor.diff:      int pair = _index[i];
       while (pair != _HashBase._UNUSED_PAIR) {
         if (pair == _HashBase._DELETED_PAIR) {
  -        if (firstDeleted < 0){
  +        if (firstDeleted < 0) {
             firstDeleted = i;
           }
         } else {
  
positive.code:   _CompactLinkedHashSet() {
      assert(_HashBase._UNUSED_PAIR == 0);
      _index = new Uint32List(_HashBase._INITIAL_INDEX_SIZE);
      _data = new List(_HashBase._INITIAL_INDEX_SIZE >> 1);
    }
  
  
negative.code: 
    void clear() {
      if (!isEmpty) {
        _init(_index.length, _hashMask, null, 0);
      }
    }
  
    void _init(int size, int hashMask, List oldData, int oldUsed) {
      _index = new Uint32List(size);
      _hashMask = hashMask;
      _data = new List(size >> 1);
  