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: 
    // method must be called only on top-level _Node
    V get(K key, [V notFound = _none]) {
      var val = _get(key, _reverseHash(key.hashCode), maxDepth);
      if(_isNone(val)){
        if (_isNone(notFound)) {
          _ThrowKeyError(key);
  
negative.code: class _TMapImpl<K, V>
          extends IterableBase<Pair<K, V>>
          implements TMap<K, V> {
    // Although PMap can be represented a simple _Node, Transient map needs
    // separate structure with a mutable reference to _Node.
    _Node _root;
  
    _Owner _owner;
  