class Foo (a :: k) where
  type family Bar (a :: k) b :: *
  	-- Defined at T7939.hs:6:4
Bar :: k -> * -> *
type family F a :: * 	-- Defined at T7939.hs:8:1
type instance F Int -- Defined at T7939.hs:9:1
F :: * -> *
type family G a :: * where G Int = Bool
  	-- Defined at T7939.hs:11:1
G :: * -> *
type family H (a :: Bool) :: Bool where H 'False = 'True
  	-- Defined at T7939.hs:14:1
H :: Bool -> Bool
type family J (a :: [k]) :: Bool where
    J '[] = 'False
    J (h : t) = 'True
  	-- Defined at T7939.hs:17:1
J :: [k] -> Bool
type family K (a :: [k]) :: Maybe k where
    K '[] = 'Nothing
    K (h : t) = 'Just h
  	-- Defined at T7939.hs:21:1
K :: [k] -> Maybe k