data Equal = Char := Int
--- fails in GHC 4.04, due to not doing fixity resolution on the lhs
--- before deciding which is the function symbol.
+-- fails in GHC (all versions), due to not doing fixity resolution on
+-- the lhs before deciding which is the function symbol.
(|-) :: Int -> Equal -> Bool
0 |- x:=y = 1 |- x:=y -- XXX fails here