anchor.diff:  }
   
   /// Base class for instantiations of [InheritedWidget] subclasses.
  -class InheritedElement extends _ProxyElement {
  +class InheritedElement extends ProxyElement {
     InheritedElement(InheritedWidget widget) : super(widget);
   
     @override
  
positive.code:   }
  
    @protected
    void notifyClients(_ProxyWidget oldWidget);
  }
  
  /// Base class for instantiations of [ParentDataWidget] subclasses.
  class ParentDataElement<T extends RenderObjectWidget> extends _ProxyElement {
    ParentDataElement(ParentDataWidget<T> widget) : super(widget);
  
    @override
  
negative.code:   }
  }
  
  /// A base class for elements that instantiate [ProxyElement]s.
  abstract class ProxyElement extends ComponentElement {
    /// Creates an element that instantiates the given widget.
    ProxyElement(ProxyWidget widget) : super(widget) {
      _builder = _build;
    }
  
    @override
    ProxyWidget get widget => super.widget;
  
    Widget _build(BuildContext context) => widget.child;
  
  