anchor.diff:    }
     return false;
   }
  +
  +bool isWidgetType(DartType type) =>
  +    DartTypeUtilities.implementsInterface(type, 'Widget', '');
  
positive.code: ];
  
  // todo (pq): consider caching lookups
  bool isWidgetType(DartType type) =>
      DartTypeUtilities.implementsInterface(type, 'Widget', '');
  
  bool isContainerType(DartType type) =>
      DartTypeUtilities.implementsInterface(type, 'Container', '');
  
  
  bool isWidgetProperty(DartType type) {
    if (isWidgetType(type)) {
  
negative.code: // BSD-style license that can be found in the LICENSE file.
  
  import 'package:analyzer/dart/element/type.dart';
  
  import '../util/dart_type_utilities.dart';
  
  var _collectionInterfaces = <InterfaceTypeDefinition>[
  