anchor.diff:            return false;
           }
         }
  -      i = _HashBase._nextProbe(i, probeDistance, sizeMask);
  -      probeDistance += 1;
  +      i = _HashBase._nextProbe(i, sizeMask);
         pair = _index[i];
       }
       if (_usedData == _data.length) {
  
positive.code:   }
  
    void _createIndex() {
      // Because we use quadratic (actually triangle number) probing it is
      // important that the size is a power of two (otherwise we could fail to
      // find an empty slot).  This is described in Knuth's The Art of Computer
      // Programming Volume 2, Chapter 6.4, exercise 20 (solution in the
      // appendix, 2nd edition).
      final size =
          _roundUpToPowerOfTwo(max(_data.length, _HashBase._INITIAL_INDEX_SIZE));
      final newIndex = new Uint32List(size);
  
negative.code: 
        int i = _HashBase._firstProbe(fullHash, sizeMask);
        int pair = index[i];
        while (pair != _HashBase._UNUSED_PAIR) {
          assert(pair != _HashBase._DELETED_PAIR);
  
  