[Haskell-cafe] Safe Haskell?

Tom Smeding x at tomsmeding.com
Mon May 3 11:40:50 UTC 2021

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

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