Cannot receive non-QObject* pointers when calling C++ methods from QML

E.g. C++ class has

class MyElement : public QObject
{
public:
    Q_INVOKABLE doStuff(MyElement *e) { qDebug() << e->objectName(); }
}

In QML:

MyElement { id: obj }

Component.onCompleted: obj.doStuff(obj)

Running this QML crashes as the pointer received in doStuff() is invalid.

Obviously MyElement has already been registered with qmlRegisterType(). Adding QML_DECLARE_TYPE(MyElement) made no difference.

The workaround is to make the pointer type a QObject* instead and then qobject_cast it to a MyElement* object. The pointer is then valid.