The QAbstractItemModel may be nullptr, in particular when it gets deleted from the outside. In some places we did check for that, via operator T* from QQmlGuard, in others we didn't. The checks were quite hard to read as "if (model)" first invokes a conversion operator on a base class and then implicitly converts the result to bool. Similarly adventurous, "if (*model)" invokes operator* on a base class and then converts the result to bool. Make all the checks explicit, and add new ones where they were missing. Also, as we already retrieve the AIM in order to check it for nullptr, re-use it for the actual operation. Task-number: QTBUG-80963 Change-Id: I3548e22e9d2bef485a1cd4acf70839eb8e599e62 Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>