This problem came up during a post-game discussion in my D&D 5e campaign last night. It concerns the curse ability of the Rakshasa and how that interacts with preparing spells. In game we managed to avoid the encounter; to the relief of the DM, as he was unsure what ruling to make in this situation.
The Rakshasa's claw attack states:
[..] and the target is cursed if it is a creature. […] The cursed target gains no benefit from finishing a short or long rest. The curse lasts until it is lifted by a remove curse or similar magic.
Our party is level 16 and has a cleric so access to the remove curse spell shouldn't pose much of an issue. However, since the cleric did not have remove curse prepared at the time a question arose as to what would happen if it was the cleric that was cursed.
The cleric's spellcasting feature states the following about preparing spells (emphasis mine):
You prepare a list of cleric spells that are available for you to cast, choosing from the cleric spell list. […] Casting the spell doesn't remove it from your list of prepared spells.
You can change your list of prepared spells when you finish a long rest. Preparing a new list of cleric spells requires time spent in prayer and meditation: at least 1 minute per spell level for each spell on your list.
We agreed that as DM's we would all likely allow the cleric to change spells while cursed as we tend toward more player-positive rulings. However we aren't sure that is the correct interpretation by RAW and ruling the other way could lead to some interesting consequences.
Does changing your list of prepared spells count as a benefit of a long rest for the purpose of the Rakshasa's curse ability?
Is it a benefit? Yes. It's certainly beneficial to be able to change spells, in that it lets you get access to spells you didn't previously have prepared, with no real downside, since it's optional.
Does it result from finishing a long rest? Yes, the rule for changing prepared spells says you may do it upon finishing a long rest, but doesn't say you can do it any other time.
Therefore it's a benefit of finishing a long rest.