apply BitVec.lt_of_getLsb
case zeroExtend
w : Nat
assign : Assignment
w✝ v : Nat
inner : BVExpr w✝
ih :
  ∀ (aig : AIG BVBit) (idx : Nat) (hidx : idx < w✝),
    ⟦{ aig := (go aig inner).val.aig, ref := (go aig inner).val.stream.getRef idx hidx }, assign.toAIGAssignment⟧ =
      (eval assign inner).getLsb idx
aig : AIG BVBit
idx : Nat
hidx : idx < v
⊢ (eval assign inner).getLsb idx = true → idx < w✝
no goals