Nuke Distribution.Compat.MonadFail

[Bodigrim]

Template Α: This PR modifies behaviour or interface

Include the following checklist in your PR:

• Patches conform to the coding conventions.
• Any changes that could be relevant to users have been recorded in the changelog.
  • Is the change significant? If so, remember to add significance: significant in the changelog file.
• The documentation has been updated, if necessary.
• Manual QA notes have been included.
• Tests have been added. (Ask for help if you don’t know how to write them! Ask for an exemption if tests are too complex for too little coverage!)

[geekosaur]

We might get some complaints from people who use cabal outside our support window (I know there are people who do it), but it's not clear that we should care.

[Bodigrim]

Control.Monad.Fail has been there since base-4.9 / GHC 8.0, which is very long time ago.

[geekosaur]

Still not very far from our support window, though. (It's kinda wide.)

[Bodigrim]

Anyway, it's not like Distribution.Compat.MonadFail was actually providing any compatibility layer.

[ulysses4ever]

Thanks!