Messenger of Allah, what do you think if a son is born to me after your passing, may I name him by your name and give him your kunya?He replied, "Yes."This was a special permission granted by the Messenger of Allah ﷺ to Ali.
حدثنا وكيع حدثنا فطر عن المنذر عن ابن الحنفية قال
يا رسول الله أرأيت إن ولد لي بعدك ولد أسميه باسمك وأكنيه بكنيتك قال نعم فكانت رخصة من رسول الله ﷺ لعلي
Its isnad is sahih, even though it appears outwardly to be a mursal narration because of his wording, "from Ibn Hanafiya, who said, Ali said," but the narration of Tirmidhi clarifies it, "from Muhammad, that is Ibn Hanafiya, from Ali bin Abu Talib, that he said, O Messenger of Allah," and so on.Fitr, with a kasrah on the fa and a sakin ta, is Ibn Khalifa, who is trustworthy and salih al-hadith. Ahmad, Ibn Main, and others confirmed his reliability.Mundhir is Ibn Yaala Thawri, discussion of whom has already been given at 606.The hadith was narrated by Abu Dawud, 4:448, and Tirmidhi, 314, who said, "a hasan sahih hadith."