Wow. One innocent message... | Oh no, please don't do this! I use the RefMonad class, but | *without* the dependency r -> m. Why not? Because I want to | manipulate (for example) STRefs in monads built on top of the | ST monad via monad transformers. So I use the same reference | type with *many different* monads! Your change would make | this impossible. I don't think so. There were really two parts to my message: 1. Have a single built-in type (Ref), rather than two (IORef and STRef). I don't see how that can be anything other than a Good Thing, can it? The primitive operations over Refs are still non-overloaded, as before: newIORef :: a -> IO (Ref IO a) newSTRef :: a -> ST s (Ref (ST s) a) ...etc... 2. Have a RefMonad type class to overload the new, read, write operations over Refs. But nothing in my message precludes also having a RefMonad2 class with two parameters, and whatever functional dependencies (or lack of them) that you like class RefMonad2 r m where new :: a -> m (r a) read :: r a -> m a write :: r a -> a -> m () instance RefMonad2 (Ref IO) IO where ... instance RefMonad2 (Ref (ST s)) (ST s) where ... So then it's only a question of who gets the name "RefMonad"! (Incidentally, so far as I know, RefMonad isn't in any of the existing libraries.) So I conclude: (1) is a win (2) is a question of what we name the new (and undoubtedly useful) class that I tendentiously called RefMonad Or am I missing something? Simon