class SingletonModel : public QStringListModel
{
    Q_OBJECT
public:
    SingletonModel(QObject* parent) : QStringListModel(parent) { }
};
// ...
qmlRegisterSingletonType<SingletonModel>(uri, 1, 0, "SingletonModel",
    [](QQmlEngine* engine, QJSEngine*) -> QObject* { return new SingletonModel; });

        Component {
            id: view
            ListView {
                model: SingletonModel
            }
        }
        function test_singletonModelCrash() {
            SingletonModel.objectName = "model"
            var o = view.createObject(root)
            // no crash: o.model = null
            o.destroy()
            compare(SingletonModel.objectName, "model")
            wait(1)
            // crash
            compare(SingletonModel.objectName, "model")
        }