The ruling on one who fasted the last day of Sha'ban to make up a missed day, then it became clear that it was the first day of Ramadan

Question:
He intends by this to make up a day he owes from Ramadan of the previous year. After the day had passed its midpoint, he was informed that this day is the first day of Ramadan. Does his fast count for the first day of Ramadan, or does it not count?

Answer:
He gets his reward, if Allah wills, but it does not count. It does not count for that [day of Ramadan], nor for that [day of make-up]. It does not count for his make-up, nor for Ramadan. It does not count for his make-up because it coincided with Ramadan, and it does not count for Ramadan because he did not intend it. Actions are by intentions, and he only has to make up that day.