anchor.diff:      assert(child is RenderSector);
       assert(child.parentData is SectorParentData);
       assert(!constraints.isInfinite);
  -    double maxChildDeltaRadius = math.max(constraints.maxWidth, constraints.maxHeight) / 2.0 - innerRadius;
  +    double maxChildDeltaRadius = math.min(constraints.maxWidth, constraints.maxHeight) / 2.0 - innerRadius;
       SectorDimensions childDimensions = child.getIntrinsicDimensions(new SectorConstraints(maxDeltaRadius: maxChildDeltaRadius), innerRadius);
       double dimension = (innerRadius + childDimensions.deltaRadius) * 2.0;
       return new BoxDimensions.withConstraints(constraints, width: dimension, height: dimension);
  
positive.code:   }
  
    void setParentData(RenderNode child) {
      if (child.parentData is! SectorChildListParentData)
        child.parentData = new SectorChildListParentData();
    }
  
negative.code:     return new SectorDimensions.withConstraints(constraints);
    }
  
    void layout(SectorConstraints constraints, { RenderNode relayoutSubtreeRoot }) {
      deltaRadius = constraints.constrainDeltaRadius(0.0);
      deltaTheta = constraints.constrainDeltaTheta(0.0);
      layoutDone();
  