fix crash if event listener is destroyed while they are being iterated

loader/include/Geode/loader/Event.hpp

@@ -133,6 +133,8 @@ namespace geode {
     private:
         friend EventListenerProtocol;
 
+        static std::unordered_set<EventListenerProtocol*>& removedListeners();
+
     public:
         Mod* sender;
 
@@ -144,6 +146,12 @@ namespace geode {
         
         virtual ~Event();
 
+        /**
+         * Get all active event listeners. You may use this to sort listeners 
+         * that have an explicit order. You should never add/remove listeners 
+         * manually however - use the enable() and disable() functions for that
+         * @warning Do not add/remove listeners manually
+         */
         static std::vector<EventListenerProtocol*>& listeners();
         /**
          * Move an event listener to the front of the queue so it is always hit 

loader/src/loader/Event.cpp

@@ -8,6 +8,7 @@ void EventListenerProtocol::enable() {
 }
 
 void EventListenerProtocol::disable() {
+    Event::removedListeners().insert(this);
     ranges::remove(Event::listeners(), this);
 }
 
@@ -21,12 +22,20 @@ void Event::postFrom(Mod* m) {
     if (m) this->sender = m;
 
     std::vector<EventListenerProtocol*> listeners_copy = Event::listeners();
-
     for (auto h : listeners_copy) {
+        // if an event listener gets destroyed in the middle of this loop, we 
+        // need to handle that
+        if (Event::removedListeners().count(h)) continue;
         if (h->passThrough(this) == ListenerResult::Stop) {
             break;
         }
     }
+    Event::removedListeners().clear();
+}
+
+std::unordered_set<EventListenerProtocol*>& Event::removedListeners() {
+    static std::unordered_set<EventListenerProtocol*> listeners;
+    return listeners;
 }
 
 std::vector<EventListenerProtocol*>& Event::listeners() {

loader/src/ui/internal/info/ModInfoPopup.cpp

@@ -559,7 +559,7 @@ bool IndexItemInfoPopup::init(IndexItemHandle item, ModListLayer* list) {
 
 void IndexItemInfoPopup::onInstallProgress(ModInstallEvent* event) {
     std::visit(makeVisitor {
-        [&](UpdateFinished) {
+        [&](UpdateFinished const&) {
             this->setInstallStatus(std::nullopt);
             
             FLAlertLayer::create(