When that happens, we need to detach (in-place conversion won't work),
so we recurse back into the same function, but the template version that
does detaching.
Task-number: QTBUG-49181
Change-Id: Idba8c29717f34c70a58fffff1412fea3acc95f98
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>