anchor.diff:    }
   
     void _initScreen() {
  -    _screen = widget.possibleScreens.firstWhere(
  -      (s) => s.screenId == widget.args?.screenId,
  -      orElse: () => null,
  +    _screen = widget.possibleScreens.firstWhereOrNull(
  +      (s) => s.screenId == widget.args.screenId,
       );
     }
   
  
positive.code:         const SizedBox(height: denseRowSpacing),
          Expanded(
            child:
                _screen != null ? _screen.build(context) : _buildSnapshotError(),
          ),
        ],
      );
  
negative.code: }
  
  class _SnapshotScreenBodyState extends State<SnapshotScreenBody> {
    Screen? _screen;
  
    @override
    void initState() {
  