A level 17 Sorcerer casts the Wish spell for an effect that would trigger the repercussions, rolls the d100, and finds they are never able to cast it again:
Finally, there is a 33 percent chance that you are unable to cast wish ever again if you suffer this stress.
Does that mean there is a spell sitting in their 9th level spell slot that they can't ever use or get rid of? Or would the sorcerer be able to swap that spell out for another 9th level?
I am not interested in the homebrew rulings, and a RAW answer would be appreciated.