I'd just like to float an idea that's related to the Class Alias proposal[1] but is perhaps somewhat simpler. We all know that Functor should have been a superclass of Monad, and indeed we now know that Applicative should be too. Making such a change would break lots of things however so the change does not happen. However in this case the Monad operations can be used to implement the Functor and Applicative class methods. So it would be nice if we could get them for free if the author did not choose to write the Functor and Applicative instances. So my suggestion is that we let classes declare default implementations of methods from super-classes. class Functor m => Monad m where {- the ordinary bits -} fmap f m = m >>= return . f So if there already is a Functor instance for m then the default implementation of fmap is not used. Does this proposal have any unintended consequences? I'm not sure. Please discuss :-) Duncan [1] http://repetae.net/recent/out/classalias.html