Due to various issues, we call change listeners on objects for which QQmlData::wasDeleted returns true (or rather, calling it on the the private's q_ptr, when we have a QObjectPrivate inheriting from ChangeListener). This can be uncovered by adding a check for this condition (like in https://codereview.qt-project.org/c/qt/qtdeclarative/+/383975), and triggering an assert or printing a warning.  Then simply run a test which covers large parts of Quick and Controls, like tst_basic or tst_fusion

Incomplete list of those issues:

• QQuickItem's dtor, we call setParentItem(nullptr) on all child items. The child items then do (basically) parent->removeChild(child) (note that parent is currently getting destroyed). And removeChild causes an itemChange