conv =>
  change (bitwise bne n 0).getBit i = n.getBit i
  rw [Nat.bitwise_getBit, Nat.zero_getBit]
case a
n i : Nat
⊢ getBit (n ^^^ 0) i = getBit n i
case a
n i : Nat
⊢ (getBit n i != false) = getBit n i