Move-only functors are not supported by the QMetaObject::invokeMethod().

    QObject* o;
    auto f = [u = std::unique_ptr<int>()]() {};
    QMetaObject::invokeMethod(o, std::move(f));

It does not compile, because the f is copied in QMetaObject::invokeMethod(QObject *context, Functor function, ...).

This bug is similar to QTBUG-60339.