Ed's "pseudo-haskell" from http://comonad.com/reader/2012/mirrored-lenses/ is now compilable?

pseudo-haskell-is-now-haskell.hs

{-# LANGUAGE RankNTypes, PolyKinds, TupleSections, TypeFamilies, TypeFamilyDependencies #-}

import Data.Kind (Type)

type LensFamily (outer :: t -> Type) (inner :: t -> Type) =
    forall a b f. Functor f => (inner a -> f (inner b)) -> (outer a -> f (outer b))

type family Snd b a = r | r -> b a where Snd b a = (a, b)
type family Fst a b = r | r -> a b where Fst a b = (a, b)
type family Id t = r | r -> t where Id x = x

fstLens :: LensFamily (Snd b) Id
fstLens f (a, b) = (, b) <$> f a

sndLens :: LensFamily (Fst a) Id
sndLens f (a, b) = (a, ) <$> f b