bool debugIsValidAncestor(RenderObjectWidget ancestor)

Subclasses should override this method to return true if the given ancestor is a RenderObjectWidget that wraps a RenderObject that can handle the kind of ParentData widget that the ParentDataWidget subclass handles.

The default implementation uses the type argument.

Source 

bool debugIsValidAncestor(RenderObjectWidget ancestor) {
  assert(T != dynamic);
  assert(T != RenderObjectWidget);
  return ancestor is T;
}