Fix signal connection nodiscard warnings (#4818)

src/common/Channel.cpp

@@ -106,7 +106,7 @@ void Channel::addMessage(MessagePtr message,
 
     if (this->messages_.pushBack(message, deleted))
     {
-        this->messageRemovedFromStart.invoke(deleted);
+        this->messageRemovedFromStart(deleted);
     }
 
     this->messageAppended.invoke(message, overridingFlags);
@@ -353,6 +353,10 @@ void Channel::onConnected()
 {
 }
 
+void Channel::messageRemovedFromStart(const MessagePtr &msg)
+{
+}
+
 //
 // Indirect channel
 //

src/common/Channel.hpp

@@ -52,7 +52,6 @@ public:
     pajlada::Signals::Signal<const QString &, const QString &, const QString &,
                              bool &>
         sendReplySignal;
-    pajlada::Signals::Signal<MessagePtr &> messageRemovedFromStart;
     pajlada::Signals::Signal<MessagePtr &, boost::optional<MessageFlags>>
         messageAppended;
     pajlada::Signals::Signal<std::vector<MessagePtr> &> messagesAddedAtStart;
@@ -114,6 +113,7 @@ public:
 
 protected:
     virtual void onConnected();
+    virtual void messageRemovedFromStart(const MessagePtr &msg);
 
 private:
     const QString name_;