Would allowing this make sense? class C a b | a -> b class C a b => S a I want to simulate a particular "class synonym" (with four superclasses instead of one C here) where the type 'b' is uninteresting for its users. Currently I have to write class C a b | a -> b class C a b => S a b | a -> b and use f :: S a b => T(a) instead of f :: S a => T(a) even though T(a) usually doesn't contain b. If it does, I would write f :: (S a, C a b) => T(a) -- __("< Marcin Kowalczyk * qrczak@knm.org.pl http://qrczak.ids.net.pl/ \__/ ^^ SYGNATURA ZASTÊPCZA QRCZAK