. have hall := ‹∀ i, i < length α → ¬UInt.getBit (UInt.lsb a) i = true›
  suffices a = 0 from absurd this ha
  suffices UInt.lsb a = 0 from UInt.eq_zero_of_lsb_eq_zero a this
  suffices ∀ i, UInt.getBit (UInt.lsb a) i = false by
    apply UInt.bitext; intros; rw [this, UInt.getBit_zero]
  intro i
  cases Nat.lt_or_ge i (length α)
  case inl hlt => exact Bool.not_eq_true _ ▸ hall i hlt
  case inr hge => exact UInt.getBit_high _ _ hge
case inr
α : Type
inst✝¹ : (n : Nat) → OfNat α n
inst✝ : UInt α
a : α
ha : a ≠ 0
h✝ : ∀ (i : Nat), i < length α → ¬UInt.getBit (UInt.lsb a) i = true
⊢ ∃ i, UInt.getBit (UInt.lsb a) i = true
no goals