rw [← hgo]
case isTrue
α : Type
inst✝² : BEq α
inst✝¹ : Hashable α
inst✝ : DecidableEq α
w : Nat
aig : AIG α
curr : Nat
hcurr : curr ≤ w
discr : aig.Ref
lhs rhs : aig.RefStream w
s : aig.RefStream curr
res : RefStreamEntry α w
h✝ : curr < w
hgo :
  go (aig.mkIfCached { discr := discr, lhs := lhs.getRef curr h✝, rhs := rhs.getRef curr h✝ }).aig (curr + 1) ⋯
      { gate := discr.gate, hgate := ⋯ } (lhs.cast ⋯) (rhs.cast ⋯)
      ((s.cast ⋯).pushRef
        (aig.mkIfCached { discr := discr, lhs := lhs.getRef curr h✝, rhs := rhs.getRef curr h✝ }).ref) =
    res
⊢ ∀ (idx : Nat) (h1 : idx < aig.decls.size) (h2 : idx < res.aig.decls.size), res.aig.decls[idx] = aig.decls[idx]
case isTrue
α : Type
inst✝² : BEq α
inst✝¹ : Hashable α
inst✝ : DecidableEq α
w : Nat
aig : AIG α
curr : Nat
hcurr : curr ≤ w
discr : aig.Ref
lhs rhs : aig.RefStream w
s : aig.RefStream curr
res : RefStreamEntry α w
h✝ : curr < w
hgo :
  go (aig.mkIfCached { discr := discr, lhs := lhs.getRef curr h✝, rhs := rhs.getRef curr h✝ }).aig (curr + 1) ⋯
      { gate := discr.gate, hgate := ⋯ } (lhs.cast ⋯) (rhs.cast ⋯)
      ((s.cast ⋯).pushRef
        (aig.mkIfCached { discr := discr, lhs := lhs.getRef curr h✝, rhs := rhs.getRef curr h✝ }).ref) =
    res
⊢ ∀ (idx : Nat) (h1 : idx < aig.decls.size)
    (h2 :
      idx <
        (go (aig.mkIfCached { discr := discr, lhs := lhs.getRef curr h✝, rhs := rhs.getRef curr h✝ }).aig (curr + 1) ⋯
                { gate := discr.gate, hgate := ⋯ } (lhs.cast ⋯) (rhs.cast ⋯)
                ((s.cast ⋯).pushRef
                  (aig.mkIfCached
                      { discr := discr, lhs := lhs.getRef curr h✝, rhs := rhs.getRef curr h✝ }).ref)).aig.decls.size),
    (go (aig.mkIfCached { discr := discr, lhs := lhs.getRef curr h✝, rhs := rhs.getRef curr h✝ }).aig (curr + 1) ⋯
              { gate := discr.gate, hgate := ⋯ } (lhs.cast ⋯) (rhs.cast ⋯)
              ((s.cast ⋯).pushRef
                (aig.mkIfCached
                    { discr := discr, lhs := lhs.getRef curr h✝, rhs := rhs.getRef curr h✝ }).ref)).aig.decls[idx] =
      aig.decls[idx]