anchor.diff:    }
   
     TransientVectorImpl _clear() {
  -    this._size = 0;F_
  +    this._size = 0;
       this._level = _SHIFT;
       this._root = this._tail = null;
       this._hashCode = null;
  
positive.code:       } else {
          lowerNode = null;
        }
        var newLowerNode = _updateVNode(lowerNode, ownerID, level - _SHIFT, index, value, didAlter);
        if (newLowerNode == lowerNode) {
          return node;
        }
  
negative.code:     }
      return newNode;
    }
  }
  
  _VNode _transientVNode(_VNode node, Owner ownerID) {
  