anchor.diff:  
     double _aspectRatio;
     double get aspectRatio => _aspectRatio;
  -  void set aspectRatio (double value) {
  -    assert(value != null);
  -    if (_aspectRatio == value)
  -      return;
  -    _aspectRatio = value;
  +  void set aspectRatio (double newAspectRatio) {
  +    assert(newAspectRatio != null);
  +    if (_aspectRatio == newAspectRatio)
  +      return;
  +    _aspectRatio = newAspectRatio;
       markNeedsLayout();
     }
   
  
positive.code: 
    Matrix4 _transform;
  
    void set transform(Matrix4 value) {
      assert(value != null);
      if (_transform == value)
        return;
      _transform = new Matrix4.copy(value);
      markNeedsPaint();
    }
  
  
negative.code:   final BoxPainter _painter;
  
    BoxDecoration get decoration => _painter.decoration;
    void set decoration (BoxDecoration newDecoration) {
      assert(newDecoration != null);
      if (newDecoration == _painter.decoration)
        return;
      _removeBackgroundImageListenerIfNeeded();
      _painter.decoration = newDecoration;
      _addBackgroundImageListenerIfNeeded();
      markNeedsPaint();
    }
  