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MarcelineVQ/foo.idr

Created March 12, 2019 23:41
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foo.idr
-- This works
Eitha : Type -> Type -> Type
Eitha b a = Either a b
[eitha]
Functor (Eitha b) where
map f (Left l) = Left (f l)
map f (Right r) = Right r
-- However, removing [eitha] results in the error:
-- Eitha b cannot be a parameter of Prelude.Functor.Functor
-- (Implementation arguments must be type or data constructors)
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