unfold foldM
m : Type u → Type v
inst✝ : Monad m
α : Type u
f : Nat → α → m α
init : α
n : Nat
⊢ foldM f init (n + 1) = do
    let x ← f 0 init
    foldM (f ∘ succ) x n
m : Type u → Type v
inst✝ : Monad m
α : Type u
f : Nat → α → m α
init : α
n : Nat
⊢ foldM.loop f (n + 1) (n + 1) init = do
    let x ← f 0 init
    foldM.loop (f ∘ succ) n n x