haskell-fail: haskell-fail (MonadFail class) haskell-fail: haskell-fail: This package contains the Control.Monad.Fail module providing haskell-fail: the MonadFail class that became available in base-4.9.0.0 for haskell-fail: older base package versions. haskell-fail: haskell-fail: haskell-fail: haskell-fail: haskell-fail: haskell-fail: