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module TypeClassTest where | |
import Prelude | |
import Unsafe.Coerce (unsafeCoerce) | |
class TwoParams a b where | |
func :: a -> b | |
instance equals :: TwoParams a a where | |
func = identity | |
else | |
instance any :: TwoParams a b where | |
func = unsafeCoerce | |
-- test2 :: forall a. a -> Array a | |
-- test2 = func | |
test3 :: forall m a. a -> m a | |
test3 = func | |
-- ^^^^ | |
-- | |
-- No type class instance was found for | |
-- | |
-- TypeClassTest.TwoParams a0 | |
-- (m1 a0) | |
-- | |
-- | |
-- while checking that type forall b a. TwoParams a b => a -> b | |
-- is at least as general as type a0 -> m1 a0 | |
-- while checking that expression func | |
-- has type a0 -> m1 a0 | |
-- in value declaration test3 | |
-- | |
-- where a0 is a rigid type variable | |
-- bound at (line 18, column 9 - line 18, column 13) | |
-- m1 is a rigid type variable | |
-- bound at (line 18, column 9 - line 18, column 13) | |
-- |
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