testsuite/tests/deriving/should_fail/T21087.hs


1
2
3
4
5
6
7
8
9
10
11

{-# language DataKinds #-}
{-# language DerivingVia #-}
{-# language TypeFamilies #-}

module T21087 where

import GHC.TypeLits

data family Z :: k

deriving via 0 instance KnownNat Z