So it turns out you got lucky on this one. When I sat down and reviewed all the code for how comparable types are typechecked, I found some issues, and the most general & elegant fix happened to fix your problem by accidental side-effect.

I did consider adding in a special case to explicitly reject the usage{{max(enum)}}but, given that there is at least one person who is relying on that, it would have been a bit too ornery and contrarian even for me.