HEq1.hs

{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE UnicodeSyntax #-}

module Abt.Class.HEq1 where

-- | Uniform variant of 'Eq' for indexed types. This is different from
-- 'Data.Functor.Eq1' in that it is properly kind polymorphic and crucially
-- heterogeneous, and it places no constraint on the index.
--
class HEq1 f where
  (===) ∷ f i → f j → Bool