[Haskell-cafe] Best way to instance Fix?

Hi! I'm trying to work out the best way to generate (ideally derive) instances for the Fix type. Here's a cut down example: data Greet x = AlloAllo x x | AuRevoir deriving Show newtype Fix f = In { out :: f (Fix f) } -- deriving Show -- DOESN'T COMPILE -- workaround instance Show (Fix Greet) where show (In i) = "In " ++ show i In other words, given a number of parametised types that I can derive, say, Ord, Eq and Show for, how should I go about getting the instances for the Fix-d version of them as well? I've tried a few things, but no luck so far. Any clues? Cheers, Sam