Possible crash when removing top rows in a custom tree model/item

You can get a crash when trying to remove the child rows of the root item if you call removeRows this way:
removeRows(0, 1, indexFromItem(rootItem));
instead of
removeRows(0, 1, QModelIndex());

It seems that when if you invoke the removeRows the first way, the persistant model index that used to refer the row is still kept in the model.