Comment 1 for bug 1222988

/*!
    \fn QMetaObject *QMetaObject::superClass() const

    Returns the meta-object of the superclass, or 0 if there is no
    such object.

    \sa className()
*/

/*!
    \internal

    Returns \a obj if object \a obj inherits from this
    meta-object; otherwise returns 0.
*/
QObject *QMetaObject::cast(QObject *obj) const
{
    if (obj) {
        const QMetaObject *m = obj->metaObject(); // <<<<<<<<<<<<--------------- crash (line 338)
        do {
            if (m == this)
                return obj;
        } while ((m = m->d.superdata));
    }
    return 0;
}