anchor.diff:      return _qualifiedName;
     }
   
  -  var _owner;
     DeclarationMirror get owner {
       if (_owner == null) {
         _owner = _library(_reflectee);
  
positive.code: 
  abstract class _LocalDeclarationMirror extends _LocalMirror
      implements DeclarationMirror {
    _LocalDeclarationMirror(this._reflectee, this._simpleName);
  
    final _reflectee;
  
    Symbol _simpleName;
    Symbol get simpleName => _simpleName;
  
    Symbol _qualifiedName = null;
  
negative.code:   }
  
    int get length => _source.length;
    bool get isEmpty => _source.isEmpty;
    bool get isNotEmpty => _source.isNotEmpty;
    V operator [](K key) => _source[key];
    bool containsKey(K key) => _source.containsKey(key);
    bool containsValue(V value) => _source.containsValue(value);
    void forEach(void f(K key, V value)) => _source.forEach(f);
    Iterable<K> get keys => _source.keys;
    Iterable<V> get values => _source.values;
    void operator []=(K key, V value) => _throw();
    V putIfAbsent(K key, V ifAbsent()) { _throw(); }
    void addAll(Map<K, V> other) => _throw();
    V remove(K key) { _throw(); }
    void clear() => _throw();
  }
  
  class _InternalMirrorError {
    final String _msg;
    const _InternalMirrorError(String this._msg);
    String toString() => _msg;
  }
  
  Map _filterMap(Map<Symbol, dynamic> old_map, bool filter(Symbol key, value)) {
  