-- Mathlib/.lake/packages/lean4/src/lean/Std/Tactic/BVDecide/Bitblast/BVExpr/Circuit/Impl/Operations/Udiv.lean
theorem blastDivSubtractShift_decl_eq (aig : AIG α) (falseRef trueRef : AIG.Ref aig)
     (n d : AIG.RefVec aig w) (wn wr : Nat) (q r : AIG.RefVec aig w) :
    ∀ (idx : Nat) (h1) (h2),
        (blastDivSubtractShift aig falseRef trueRef n d wn wr q r).aig.decls[idx]'h2 = aig.decls[idx]'h1

Proof state:
α : Type
inst✝¹ : Hashable α
inst✝ : DecidableEq α
w : Nat
aig : AIG α
falseRef trueRef : aig.Ref
n d : aig.RefVec w
wn wr : Nat
q r : aig.RefVec w
res : BlastDivSubtractShiftOutput aig w
hres :
  (let wn_1 := wn - 1;
    let wr := wr + 1;
    let res := blastShiftConcat aig { lhs := r, bit := n.getD wn_1 falseRef };
    let aig_1 := res.aig;
    let r' := res.vec;
    let_fun this := ⋯;
    let falseRef_1 := falseRef.cast this;
    let trueRef_1 := trueRef.cast this;
    let d_1 := d.cast this;
    let q_1 := q.cast this;
    let res_1 := blastShiftConcat aig_1 { lhs := q_1, bit := falseRef_1 };
    let aig_2 := res_1.aig;
    let posQ := res_1.vec;
    let_fun this_1 := ⋯;
    let trueRef_2 := trueRef_1.cast this_1;
    let d_2 := d_1.cast this_1;
    let q_2 := q_1.cast this_1;
    let r' := r'.cast this_1;
    let res := blastShiftConcat aig_2 { lhs := q_2, bit := trueRef_2 };
    let aig_3 := res.aig;
    let negQ := res.vec;
    let_fun this_2 := ⋯;
    let d_3 := d_2.cast this_2;
    let r' := r'.cast this_2;
    let posQ := posQ.cast this_2;
    let res_2 := blastSub aig_3 { lhs := r', rhs := d_3 };
    let aig_4 := res_2.aig;
    let negR := res_2.vec;
    let_fun this_3 := ⋯;
    let d_4 := d_3.cast this_3;
    let r'_1 := r'.cast this_3;
    let posQ := posQ.cast this_3;
    let negQ := negQ.cast this_3;
    let posR := r'_1;
    let res := BVPred.mkUlt aig_4 { lhs := r'_1, rhs := d_4 };
    let aig_5 := res.aig;
    let discr := res.ref;
    let_fun this_4 := ⋯;
    let posQ := posQ.cast this_4;
    let negQ := negQ.cast this_4;
    let posR := posR.cast this_4;
    let negR := negR.cast this_4;
    let res_3 := AIG.RefVec.ite aig_5 { discr := discr, lhs := posQ, rhs := negQ };
    let aig_6 := res_3.aig;
    let nextQ := res_3.vec;
    let_fun this_5 := ⋯;
    let posR := posR.cast this_5;
    let negR := negR.cast this_5;
    let discr := discr.cast this_5;
    let res := AIG.RefVec.ite aig_6 { discr := discr, lhs := posR, rhs := negR };
    ⋯) =
    res
⊢ ∀ (idx : Nat) (h1 : idx < aig.decls.size) (h2 : idx < res.aig.decls.size), res.aig.decls[idx] = aig.decls[idx]

Tactic:
dsimp only at hres

Result:
α : Type
inst✝¹ : Hashable α
inst✝ : DecidableEq α
w : Nat
aig : AIG α
falseRef trueRef : aig.Ref
n d : aig.RefVec w
wn wr : Nat
q r : aig.RefVec w
res : BlastDivSubtractShiftOutput aig w
hres :
  {
      aig :=
        (AIG.RefVec.ite
            (AIG.RefVec.ite
                (BVPred.mkUlt
                    (blastSub
                        (blastShiftConcat
                            (blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                            { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                        {
                          lhs :=
                            ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯,
                          rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                    {
                      lhs :=
                        (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯).cast
                          ⋯,
                      rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).aig
                {
                  discr :=
                    (BVPred.mkUlt
                        (blastSub
                            (blastShiftConcat
                                (blastShiftConcat
                                    (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                            {
                              lhs :=
                                ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                  ⋯,
                              rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                        {
                          lhs :=
                            (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                  ⋯).cast
                              ⋯,
                          rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).ref,
                  lhs :=
                    (((blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).vec.cast
                              ⋯).cast
                          ⋯).cast
                      ⋯,
                  rhs :=
                    ((blastShiftConcat
                                (blastShiftConcat
                                    (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).vec.cast
                          ⋯).cast
                      ⋯ }).aig
            {
              discr :=
                (BVPred.mkUlt
                        (blastSub
                            (blastShiftConcat
                                (blastShiftConcat
                                    (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                            {
                              lhs :=
                                ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                  ⋯,
                              rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                        {
                          lhs :=
                            (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                  ⋯).cast
                              ⋯,
                          rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).ref.cast
                  ⋯,
              lhs :=
                (((((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯).cast
                          ⋯).cast
                      ⋯).cast
                  ⋯,
              rhs :=
                ((blastSub
                            (blastShiftConcat
                                (blastShiftConcat
                                    (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                            {
                              lhs :=
                                ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                  ⋯,
                              rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).vec.cast
                      ⋯).cast
                  ⋯ }).aig,
      wn := wn - 1, wr := wr + 1,
      q :=
        (AIG.RefVec.ite
                (BVPred.mkUlt
                    (blastSub
                        (blastShiftConcat
                            (blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                            { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                        {
                          lhs :=
                            ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯,
                          rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                    {
                      lhs :=
                        (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯).cast
                          ⋯,
                      rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).aig
                {
                  discr :=
                    (BVPred.mkUlt
                        (blastSub
                            (blastShiftConcat
                                (blastShiftConcat
                                    (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                            {
                              lhs :=
                                ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                  ⋯,
                              rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                        {
                          lhs :=
                            (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                  ⋯).cast
                              ⋯,
                          rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).ref,
                  lhs :=
                    (((blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).vec.cast
                              ⋯).cast
                          ⋯).cast
                      ⋯,
                  rhs :=
                    ((blastShiftConcat
                                (blastShiftConcat
                                    (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).vec.cast
                          ⋯).cast
                      ⋯ }).vec.cast
          ⋯,
      r :=
        (AIG.RefVec.ite
            (AIG.RefVec.ite
                (BVPred.mkUlt
                    (blastSub
                        (blastShiftConcat
                            (blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                            { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                        {
                          lhs :=
                            ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯,
                          rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                    {
                      lhs :=
                        (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯).cast
                          ⋯,
                      rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).aig
                {
                  discr :=
                    (BVPred.mkUlt
                        (blastSub
                            (blastShiftConcat
                                (blastShiftConcat
                                    (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                            {
                              lhs :=
                                ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                  ⋯,
                              rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                        {
                          lhs :=
                            (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                  ⋯).cast
                              ⋯,
                          rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).ref,
                  lhs :=
                    (((blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).vec.cast
                              ⋯).cast
                          ⋯).cast
                      ⋯,
                  rhs :=
                    ((blastShiftConcat
                                (blastShiftConcat
                                    (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).vec.cast
                          ⋯).cast
                      ⋯ }).aig
            {
              discr :=
                (BVPred.mkUlt
                        (blastSub
                            (blastShiftConcat
                                (blastShiftConcat
                                    (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                            {
                              lhs :=
                                ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                  ⋯,
                              rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                        {
                          lhs :=
                            (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                  ⋯).cast
                              ⋯,
                          rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).ref.cast
                  ⋯,
              lhs :=
                (((((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯).cast
                          ⋯).cast
                      ⋯).cast
                  ⋯,
              rhs :=
                ((blastSub
                            (blastShiftConcat
                                (blastShiftConcat
                                    (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                    { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                            {
                              lhs :=
                                ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                  ⋯,
                              rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).vec.cast
                      ⋯).cast
                  ⋯ }).vec,
      hle := ⋯ } =
    res
⊢ ∀ (idx : Nat) (h1 : idx < aig.decls.size) (h2 : idx < res.aig.decls.size), res.aig.decls[idx] = aig.decls[idx]