anchor.diff:      );
     }
   
  -  Size _getChartSize() {
  -    final RenderBox containerRenderBox = _chartKey.currentContext?.findRenderObject();
  -    if (containerRenderBox != null && containerRenderBox.hasSize) {
  +  Size? _getChartSize() {
  +    final containerRenderBox = _chartKey.currentContext?.findRenderObject();
  +    if (containerRenderBox == null || containerRenderBox is! RenderBox) {
  +      return null;
  +    }
  +    if (containerRenderBox.hasSize) {
         return containerRenderBox.size;
       }
       return null;
  
positive.code:     _lineChartDataTween = visitor(
        _lineChartDataTween,
        _getData(),
        (dynamic value) => LineChartDataTween(begin: value),
      );
    }
  }
  
negative.code:   }
  
    void _handleBuiltInTouch(LineTouchResponse touchResponse) {
      widget.data.lineTouchData.touchCallback?.call(touchResponse);
  
      if (touchResponse.touchInput is FlPanStart ||
          touchResponse.touchInput is FlPanMoveUpdate ||
  