anchor.diff:  
     @override
     List<String> get shownNames {
  -    if (_shownNames != null) return _shownNames!;
  +    if (!identical(_shownNames, _Sentinel.string)) {
  +      return _shownNames;
  +    }
   
       if (linkedNode != null) {
         return _shownNames = linkedNode!.shownNames.map((i) => i.name).toList();
       }
   
  -    return _shownNames ?? const <String>[];
  +    return _shownNames;
     }
   
     set shownNames(List<String> shownNames) {
  
positive.code:         return element;
        }).toList();
  
        if (_constructors!.isEmpty) {
          return _constructors = [
            ConstructorElementImpl.forLinkedNode(
              this,
  
negative.code: 
    /// The initializers for this constructor (used for evaluating constant
    /// instance creation expressions).
    List<ConstructorInitializer> _constantInitializers =
        _Sentinel.constructorInitializer;
  
    /// The offset of the `.` before this constructor name or `null` if not named.
    int? _periodOffset;
  