. next i_out_of_bounds =>
  exfalso
  exact i_out_of_bounds i_size
case isFalse
α : Type u_1
a : Array α
i : Nat
i_size : i < a.size
j : Nat
j_size : j < a.size
f : α → α
h : i ≠ j
h✝ : ¬i < a.size
⊢ (a.set ⟨i, ⋯⟩ (f (a.get ⟨i, ⋯⟩)))[j] = a[j]
no goals