GHC doesn't like 'inline' type function applications

{-# LANGUAGE TypeFamilies #-}

import Prelude hiding (foldl, foldr, foldl1, foldr1, mapM_, sequence_,
		elem, notElem, concat, concatMap, and, or, any, all,
		sum, product, maximum, minimum)
import Data.Monoid

type family Element t

class Foldable t where
        foldMap :: Monoid m => (Element t -> m) -> t -> m

	foldr :: (Element t -> b -> b) -> b -> t -> b
	-- foldr :: Element t ~ a => (a -> b -> b) -> b -> t -> b
	foldr f z t = appEndo (foldMap (Endo . f) t) z

GHC chokes on the above module. If the signature of foldr is replaced by the commented one, GHC is happy. It seems to me that the two expressions should be equivalent.

Trac metadata

Trac field	Value
Version	6.9
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler (Type checker)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system	Unknown
Architecture	Unknown