anchor.diff:  // 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>[
  
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:   }
    return false;
  }
  
  bool isWidgetType(DartType type) =>
      DartTypeUtilities.implementsInterface(type, 'Widget', '');
  