Convert TraverseState::new_goals and TraverseState::removed_goals…

… into `std::vector` and push/pop instead of insert/erase.

These containers were never used to check set membership during the loop, it was practically being used to later construct a set after the algorithm, of which in previous state of the code it made sense(because it was being copied all over the place), but while traversing the problem space through DFS it doesn't make sense just because pushing and poping on a `std::vector` is way more cheaper than insertion and deletion within a `std::set`, as we only want to remember the increment of the state change between DFSs.

PiperOrigin-RevId: 707890975

pytype/typegraph/solver.cc

@@ -36,9 +36,8 @@ struct RemoveResult {
 struct TraverseState {
   GoalSet goals_to_remove;
   GoalSet seen_goals;
-  GoalSet removed_goals;
-  GoalSet new_goals;
-  TraverseState() {}
+  std::vector<const Binding*> removed_goals;
+  std::vector<const Binding*> new_goals;
 };
 
 enum ActionType {
@@ -78,8 +77,9 @@ static void traverse(const CFGNode* position,
                      std::vector<RemoveResult>& results,
                      std::stack<Action>& actions, TraverseState& state) {
   if (state.goals_to_remove.empty()) {
-    results.emplace_back(GoalSet(state.removed_goals),
-                         GoalSet(state.new_goals));
+    results.emplace_back(
+        GoalSet(state.removed_goals.begin(), state.removed_goals.end()),
+        GoalSet(state.new_goals.begin(), state.new_goals.end()));
     return;
   }
 
@@ -92,23 +92,19 @@ static void traverse(const CFGNode* position,
     actions.emplace(TRAVERSE, nullptr);
     return;
   }
-  auto [it, added] = state.seen_goals.insert(goal);
+  auto [it, _] = state.seen_goals.insert(goal);
   actions.emplace(ERASE_SEEN_GOALS, nullptr, it);
 
   const auto* origin = goal->FindOrigin(position);
   if (!origin) {
-    std::tie(it, added) = state.new_goals.insert(goal);
-    if (added) {
-      actions.emplace(ERASE_NEW_GOALS, nullptr, it);
-    }
+    state.new_goals.push_back(goal);
+    actions.emplace(ERASE_NEW_GOALS, nullptr);
     actions.emplace(TRAVERSE, nullptr);
     return;
   }
 
-  std::tie(it, added) = state.removed_goals.insert(goal);
-  if (added) {
-    actions.emplace(ERASE_REMOVED_GOALS, nullptr, it);
-  }
+  state.removed_goals.push_back(goal);
+  actions.emplace(ERASE_REMOVED_GOALS, nullptr);
   for (const auto& source_set : origin->source_sets) {
     for (const Binding* next_goal : source_set) {
       if (!state.goals_to_remove.count(next_goal)) {
@@ -163,10 +159,10 @@ static std::vector<RemoveResult> remove_finished_goals(const CFGNode* pos,
         state.seen_goals.erase(action.erase_it);
         break;
       case ERASE_NEW_GOALS:
-        state.new_goals.erase(action.erase_it);
+        state.new_goals.pop_back();
         break;
       case ERASE_REMOVED_GOALS:
-        state.removed_goals.erase(action.erase_it);
+        state.removed_goals.pop_back();
         break;
     }
   }