blob: 2682d6242fa770c5ad289193328d8996d8135301 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
|
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE TypeFamilies #-}
module T14933 where
class Wrapped s where
type Unwrapped s :: *
class Fork m where
fork :: (x, m)
default fork :: ( Wrapped m
, Unwrapped m ~ t
, Fork t
) => (x, m)
fork = undefined
newtype MyThing m = MyThing m
deriving Fork
instance Wrapped (MyThing m) where
type Unwrapped (MyThing m) = m
|
