anchor.diff:    }
   
     TMap<K, V> doDelete(K key, {bool missingOk: false}) {
  -    return _adjustRootAndReturn(_root._delete(owner, key, _reverseHash(key.hashCode), maxDepth, missingOk));
  +    return _adjustRootAndReturn(_root._delete(owner, key, _mangleHash(key.hashCode), maxDepth, missingOk));
     }
   
     TMap<K, V> doUpdate(K key, dynamic updateF) {
  
positive.code:   }
  }
  
  _reverseHash(hash){
    var _tmp = hash ^ (hash << 8);
    return ((_tmp ^ (_tmp << 16)) & allHashMask);
  }
  
  _getBranch(hash, depth){
    return (hash >> (depth*branchingBits)) & branchingMask;
  
negative.code:     return pairs.iterator;
    }
  
    /// check whether order-by-hashcode invariant (see technical.md) holds
    void sanityCheck(){
      var lasthash = double.NEGATIVE_INFINITY;
      for (int i=0; i<_kv.length; i+=recsize){
  