Don't import Safe ST modules for modern versions of base

[konsumlamm]

Control.Monad.ST.Safe and Control.Monad.ST.Lazy.Safe are deprecated since base-4.8, so only import them for olderbase versions. I think it would be reasonable to drop support for base < 4.8, as that would allow to get rid of a bunch of CPP, but I have not done that in this PR.

With this change, transformers-base compiles with MicroHs, so update the .gitignore to also match dist-mcabal.

[mvv]

Hello. Deprecated != unusable. People who opt for deprecated stuff in base should be able to use it with transformers-base. Why not simply guard code that breaks MicroHs with an #if that checks against that compiler?

[konsumlamm]

Deprecated != unusable.

Sure, but it means that it might be removed in the future.

People who opt for deprecated stuff in base should be able to use it with transformers-base.

I'm not sure I understand. Control.Monad.ST and Control.Monad.ST.Safe literally export the same types and functions (as do Control.Monad.ST.Lazy and Control.Monad.ST.Lazy.Safe), so nothing changes for users of this library.

Why not simply guard code that breaks MicroHs with an #if that checks against that compiler?

I could do that, if you insist, but I don't see why that would be better.

[mvv]

Ah, missed the same types bit. Could you keep the imports inside #if MIN_VERSION_base(4,4,0) && HS_TRANSFORMERS_BASE__ORPHANS intact and transform the second modified #if block to

#if MIN_VERSION_base(4,4,0)
# if MIN_VERSION_base(4,8,0)
import qualified Control.Monad.ST.Lazy as L
import qualified Control.Monad.ST.Strict as S
# else
import qualified Control.Monad.ST.Lazy.Safe as L
import qualified Control.Monad.ST.Safe as S
# endif
#endif

?

[konsumlamm]

Like this?

[mvv]

Uploaded new version to Hackage. Thanks.