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Problem 2, when trying to compile for tracing:

module T1 where instance (Enum a, Bounded a, Eq b) => Eq (a -> b) where f1 == f2 = and [f1 x == f2 x | x <- [minBound .. maxBound]]

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Fail: The class Prelude.Enum has no instance for the type Prelude.R. Possible sources for the problem are: 9:6

Ok, the problem here is not so much a bug but more of a restriction on how the tracing mechanism works. There is a workaround, although I'm afraid it may not be suitable for your application - declare a newtype or data for the function arrow, e.g. module T1 where newtype Func a b = Func (a->b) instance (Enum a, Bounded a, Eq b) => Eq (Func a b) where (Func f1) == (Func f2) = and [f1 x == f2 x | x <- [minBound .. maxBound]] Then you will need to wrap each function in a Func constructor before doing the equality comparison. Regards, Malcolm