The Ruling of Oversleeping when Fasting.
Ash Shaykh Saalih al Fawzaan, may Allaah preserve him, was asked: There is a person who prohibits (the people from) over sleeping in Ramaadan and says” it is upon a Muslim to be awake and active, it is not
appropriate that he over sleeps”.So what is your opinion Oh noble
A: Yes he should warn from over sleeping in this Month (Ramadaan), I
mean sleeping in the day (time) because it makes (one) lazy from
performing acts of obedience, perhaps it may cause one to miss the congregation prayer or it may cause the time for (that specific prayer) to pass by. What is requested from a Muslim is that he be energetic in
acts of obedience and (that) he sleeps in the night, especially in the
first part of it (the night), so he can arise in the morning energetic to perform and participate in acts of obedience.
The Reference: al Muntaqaa, (111/5) , fatwa number:167