loopHelper : (n : ℕ) → (env : Envc ) → (eq : varn env ≡ n) → (seq : whileTestStateP s2 env)
           → loopPwP' n env (sym eq) seq (λ env₁ x → (vari env₁ ≡ c10 env₁))
loopHelper zero env eq refl rewrite eq = refl
loopHelper (suc n) env refl refl =
           loopHelper n (record { c10 = suc (n + vari env) ; varn = n ; vari = suc (vari env) }) refl (+-suc n (vari env))