class declaration in boot file

I'm trying to solve a circularity problem with .hs-boot, but am getting the error: "Illegal class declaration in hs-boot file". The offending declaration is: class (Monad m, Functor m, Eq a, Data a, Typeable a) => ICoercible m a | a -> m I've tried with and without the fundeps. Data and Typeable are in scope, and -fglasgow-exts is set. Any ideas on what else I should be doing? -- Gaal Yahas http://gaal.livejournal.com/