Main.purs

module Main where

times :: forall a f. Semigroup f a (Int -> a -> a)
times n x = times n x

-- Adding explicit types doesn't work either
-- times' :: forall a f. Semigroup f a (Int -> a -> a)
-- times' n x = (times' :: Semigroup f a (Int -> a -> a)) n x

-- This doesn't work either
-- times'' :: forall a f. Associate f a => Op f a => Int -> a -> a
-- times'' n x = times'' n x

class Op f a where
  op :: f a -> f a -> f a

class Op f a <= Associate f a
type Magma f a b = Op f a => b
type Semigroup f a b = Associate f a => Magma f a b