. next heq =>
  rw [mkAtom, Array.get_push_size] at heq
  contradiction
case h_3
α : Type
inst✝² : BEq α
inst✝¹ : Hashable α
inst✝ : DecidableEq α
var : α
assign : α → Bool
aig : AIG α
lidx✝ ridx✝ : Nat
linv✝ rinv✝ : Bool
heq✝ : (aig.mkAtom var).aig.decls[(aig.mkAtom var).ref.gate] = Decl.gate lidx✝ ridx✝ linv✝ rinv✝
⊢ (let_fun this := ⋯;
    let lval := denote.go lidx✝ (aig.mkAtom var).aig.decls assign ⋯ ⋯;
    let rval := denote.go ridx✝ (aig.mkAtom var).aig.decls assign ⋯ ⋯;
    xor lval linv✝ && xor rval rinv✝) =
    assign var
no goals