Is a Wizard unable to regain spell slots and change their list of spells after finishing/completing a long rest when affected by Nightmare Haunting (MM 178)? Or are the benefits from the rest limited to those on PH 186?

— Eric Green (@quadhund) March 19, 2020

If you're affected by the night hag's Nightmare Haunting during a short/long rest, you gain no benefits from that rest.

In D&D, a rest's benefits are extensible. Some of its benefits come from the rest rules (PH 186), and some might come from a feature like Arcane Recovery. #DnD https://t.co/KWVQR7Vuif

— Jeremy Crawford (@JeremyECrawford) April 17, 2020

Sure thing! And I'm glad you brought your tweet to my attention. Twitter has been devouring my notifications faster and faster lately. I see only a tiny percentage of them.

— Jeremy Crawford (@JeremyECrawford) April 17, 2020