On 03/05/2021 12:53, Oleg Grenrus wrote:
... - OTOH, safety is peculiar, so there probably was a discussion justifying current behavior, which is to prohibit overriding. (Probably one argument is that if the extensions are in module, then sorting them shouldn't change the result! with Safe Haskell it's harder to spot - you have to write tests - than with mixing up Haskell98/2010/GHC2021).
I'm just a user, but I would be quite surprised if sorting the list of language extension pragmas in a module changes the semantics -- particularly for something safety-related. I would accept this behaviour for the Haskell98/... flags because if you have multiple of those explicitly listed in a file, you're doing something wrong anyway. But perhaps I'm being ignorant of other existing cases where this already matters, and I've been living in an idealised world until now. - Tom