apply congrArg
F : Type u → Type u
inst : QPF F
R S : Type u
f : F (Free F R)
k : R → Free F S
⊢ construct (corec (bind.automaton k) <$> FreeF.Free (Sum.inl <$> f)) =
    construct (FreeF.Free ((fun a => corec (bind.automaton k) (Sum.inl a)) <$> f))
case h
F : Type u → Type u
inst : QPF F
R S : Type u
f : F (Free F R)
k : R → Free F S
⊢ corec (bind.automaton k) <$> FreeF.Free (Sum.inl <$> f) =
    FreeF.Free ((fun a => corec (bind.automaton k) (Sum.inl a)) <$> f)