[Haskell-cafe] Having trouble with instance context

I am trying to create an instance of a class for data types deriving from Enum. When I try to specify this through a context on the instance definition, I get an error. When I do something similar with a function, it seems to work fine. Why does the instance not work? {------------ Example: ---------------} class Test t where func :: t -> Int -- This instance does not compile instance (Enum e) => Test e where func x = fromEnum x -- This function does work newfunc :: (Enum e) => e -> Int newfunc x = fromEnum x Thanks, Kurt