apply Eq.trans _ (QPF.map_id _)
case refl.left
F : Type u → Type u
inst : QPF F
R S : Type u
k : R → Free F S
x y : QPF.M (FreeF F S)
⊢ (fun x => x) <$> QPF.M.destruct x = QPF.M.destruct x
F : Type u → Type u
inst : QPF F
R S : Type u
k : R → Free F S
x y : QPF.M (FreeF F S)
⊢ (fun x => x) <$> QPF.M.destruct x = id <$> QPF.M.destruct x