Fwd: Misleading documentation for `fail`

Artem Pelenitsyn a.pelenitsyn at gmail.com
Fri Feb 7 02:47:29 UTC 2020


The fail package [1] lists libraries at haskell.org as maintainer's address,
so I'm writing here. The documentation for the single module in the package

This module can be imported for defining forward compatible MonadFail

import qualified Control.Monad.Fail as Fail

instance Monad Foo where
  (>>=) = {- ...bind impl... -}

  -- Provide legacy fail implementation for when
  -- new-style MonadFail desugaring is not enabled.
  fail = Fail.fail

But defining the fail method inside a Monad instance will produce an error
on GHC 8.8+. Should this bit be removed?

Best, Artem

[1]: http://hackage.haskell.org/package/fail
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