anchor.diff:        new_map[key] = value;
       }
     });
  -  return new _UnmodifiableMapView(new_map);
  +  return new UnmodifiableMapView(new_map);
   }
   
   Map _makeMemberMap(List mirrors) {
  -  return new _UnmodifiableMapView<Symbol, DeclarationMirror>(
  +  return new UnmodifiableMapView<Symbol, DeclarationMirror>(
         new Map<Symbol, DeclarationMirror>.fromIterable(
             mirrors, key: (e) => e.simpleName));
   }
  
positive.code:         }
        });
        _cachedInstanceMembers =
            new _UnmodifiableMapView<Symbol, MethodMirror>(result);
      }
      return _cachedInstanceMembers;
    }
  
negative.code:   Map<Symbol, DeclarationMirror> get declarations {
      if (_declarations != null) return _declarations;
      return _declarations =
          new UnmodifiableMapView<Symbol, DeclarationMirror>(_members);
    }
  
    Map<Symbol, Mirror> _cachedMembers;
  