ghc hung by FunctionalDependencies/UndecidableInstances

[Roland Zumkeller]

Hi,

ghc seems to hang and eat memory when fed the following code:

{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies,
UndecidableInstances #-}
class C a b | a -> b where f :: a -> b
newtype T a = T a
instance (C a b, Eq b) => Eq (T a) where (==) = undefined
g x = (undefined :: a -> a -> a -> ()) (T x) (f x) (undefined :: Eq a => a)

Is this a bug?

Best,

Roland

-- 
http://alacave.net/~roland/