anchor.diff:    }
   
     void _paintBorderWithCircle(Canvas canvas, Rect rect) {
  -    assert(_hasUniformBorder);
  +    assert(_decoration.border.isUniform);
       assert(_decoration.shape == BoxShape.circle);
       assert(_decoration.borderRadius == null);
       double width = _decoration.border.top.width;
  
positive.code:   }
  
    void _paintBorderWithRadius(Canvas canvas, Rect rect) {
      assert(_hasUniformBorder);
      assert(_decoration.shape == BoxShape.rectangle);
      Color color = _decoration.border.top.color;
      double width = _decoration.border.top.width;
  
negative.code:   bool operator ==(dynamic other) {
      if (identical(this, other))
        return true;
      if (other.runtimeType != runtimeType)
        return false;
      final Border typedOther = other;
      return top == typedOther.top &&
  