Is it permissible to combine the intention of making up missed days and expiation for an oath (kaffarat al-yamin) in a single fast?

It is not permissible to combine the fasting of expiation (kaffarah) with the fasting of make-up (qada'), because each of them is intended by the Lawgiver for a specific purpose. Therefore, the days of make-up fasting must be observed independently, and the days of expiation fasting must be observed independently. Al-Bahuti mentioned in "Al-Muntaha" that if someone intends, outside of Ramadan, to fast for make-up and supererogatory (nafl) or a vow (nadhr) or expiation, their fast will be considered supererogatory.