anchor.diff:      throw 'Dummy extension method to make the code type check when it calls private members';
     }
   
  -  List<String> /*?*/ get _pubRootDirectories {
  +  List<String>? get _pubRootDirectories {
       throw 'Dummy extension method to make the code type check when it calls private members';
     }
   }
  
positive.code: // widget_inspector.dart library so using protected members is fine.
  // ignore_for_file: invalid_use_of_visible_for_testing_member
  // ignore_for_file: invalid_use_of_protected_member
  
  // This annotation should stay here for compatibility with legacy code.
  // @dart=2.9
  
  import 'dart:async';
  import 'dart:convert';
  
negative.code:     final groupName = parameters['groupName'];
  
      final result = instance._nodeToJson(
        WidgetsBinding.instance.renderViewElement?.toDiagnosticsNode(),
        InspectorSerializationDelegate(
          groupName: groupName,
          subtreeDepth: 1000000,
  