[Haskell-cafe] Principal type in Haskell

Hi All, I am confused by the notion of principal type in Haskell with type classes. Consider a simple example: f x y = [x] == [y] GHCi yields type f :: (Eq [a]) => a -> a -> Bool. But according to the paper "Type classes: an exploration of the design space", predicate Eq [a] should be reduced to Eq a. Is this reduction performed here? What should be the principal type of f? Thanks. william _________________________________________________________________ Get an advanced look at the new version of MSN Messenger. http://messenger.msn.com.sg/Beta/Default.aspx