ref: f292a26d47527ae5dd9de040754c6d0a64a162da
dir: /lib/Control/Monad/Fail.hs/
module Control.Monad.Fail(MonadFail(..)) where import Primitives import Control.Applicative import Control.Error import Control.Monad import Data.Char import Data.List_Type class Monad m => MonadFail m where fail :: forall a . String -> m a fail = error instance MonadFail [] where fail _ = []