cases (Array.mem_push ..).mp hj with
| inl hj => exact inv.2 j hj
| inr hj => contradiction
nfa : NFA
pos : String.Pos
next : SparseSet nfa.nodes.size
currentSave : Array (Option String.Pos)
matched : Option (Array (Option String.Pos))
saveSlots : Data.Vec (Array (Option String.Pos)) nfa.nodes.size
target : Fin nfa.nodes.size
stack : Array (StackEntry nfa.nodes.size)
matched' : Option (Array (Option String.Pos))
next' : SparseSet nfa.nodes.size
saveSlots' : Data.Vec (Array (Option String.Pos)) nfa.nodes.size
i : Fin nfa.nodes.size
inv : UpperInvExploreεClosure nfa i target stack
h✝¹ : target ∉ next
offset✝ target' : ℕ
hn : nfa[↑target] = Node.save offset✝ target'
isLt : (Node.save offset✝ target').inBounds nfa.nodes.size
h✝ : offset✝ < currentSave.size
h :
  exploreεClosure nfa pos (next.insert target) (currentSave.set ⟨offset✝, ⋯⟩ (some pos)) matched saveSlots ⟨target', ⋯⟩
      (stack.push (StackEntry.restore currentSave)) =
    (matched', next', saveSlots')
j : Fin nfa.nodes.size
hj : StackEntry.explore j ∈ stack.push (StackEntry.restore currentSave)
⊢ ↑j ∈ nfa.εClosure ↑i
no goals