I had proposed this to the GHC Trac, but it was pointed out that it would break Haskell 98. That proposal has been closed. Proposal: Make Applicative (in Control.Applicative) a superclass of Monad (in Control.Monad). Rename members of Applicative and other functions, to avoid unnecessary duplication. Generalise types of certain existing functions, as appropriate. For example: class Functor f => Applicative f where return :: a -> f a ap :: f (a -> b) -> f a -> f b (>>) :: f a -> f b -> f b (>>) = liftA2 (const id) liftA2 :: Applicative f => (a -> b -> c) -> f a -> f b -> f c liftA2 f a b = ap (fmap f a) b -- etc. class Applicative m => Monad m where (>>=) :: m a -> (a -> m b) -> m b fail :: String -> m a fail s = error s -- Ashley Yakeley