Fix IRC mentions not showing up in the /mentions split (#3400)

CHANGELOG.md

@@ -67,6 +67,7 @@
 - Bugfix: Fixed IRC highlights not triggering sounds or alerts properly. (#3368)
 - Bugfix: Fixed IRC /kick command crashing if parameters were malformed. (#3382)
 - Bugfix: Fixed crash that would occur if the user tries to modify the currently connected IRC connection. (#3398)
+- Bugfix: Fixed IRC mentions not showing up in the /mentions split. (#3400)
 - Bugfix: Fixed a crash that could occur on certain Linux systems when toggling the Always on Top flag. (#3385)
 - Bugfix: Fixed zero-width emotes sometimes wrapping lines incorrectly. (#3389)
 - Bugfix: Fixed using special chars in Windows username breaking the storage of custom commands (#3397)

src/providers/irc/IrcServer.cpp

@@ -8,6 +8,7 @@
 #include "providers/irc/Irc2.hpp"
 #include "providers/irc/IrcChannel2.hpp"
 #include "providers/irc/IrcMessageBuilder.hpp"
+#include "providers/twitch/TwitchIrcServer.hpp"  // NOTE: Included to access the mentions channel
 #include "singletons/Settings.hpp"
 #include "util/IrcHelpers.hpp"
 #include "util/QObjectRef.hpp"
@@ -184,8 +185,18 @@ void IrcServer::privateMessageReceived(Communi::IrcPrivateMessage *message)
 
         if (!builder.isIgnored())
         {
-            channel->addMessage(builder.build());
+            auto msg = builder.build();
+
+            channel->addMessage(msg);
             builder.triggerHighlights();
+            const auto highlighted = msg->flags.has(MessageFlag::Highlighted);
+            const auto showInMentions =
+                msg->flags.has(MessageFlag::ShowInMentions);
+
+            if (highlighted && showInMentions)
+            {
+                getApp()->twitch2->mentionsChannel->addMessage(msg);
+            }
         }
         else
         {