diff --git a/src/persistence/offlinemsgengine.cpp b/src/persistence/offlinemsgengine.cpp
index c3667646c..54f20d4b6 100644
--- a/src/persistence/offlinemsgengine.cpp
+++ b/src/persistence/offlinemsgengine.cpp
@@ -81,21 +81,24 @@ void OfflineMsgEngine::deliverOfflineMsgs()
     QMap<int, MsgPtr> msgs = undeliveredMsgs;
     removeAllReciepts();
 
-    for (auto iter = msgs.begin(); iter != msgs.end(); iter++)
-    {
-        if (iter.value().timestamp.msecsTo(QDateTime::currentDateTime()) < offlineTimeout)
+    for (auto iter = msgs.begin(); iter != msgs.end(); ++iter)
+    {
+        auto val = iter.value();
+        auto key = iter.key();
+
+        if (val.timestamp.msecsTo(QDateTime::currentDateTime()) < offlineTimeout)
         {
-            registerReceipt(iter.value().receipt, iter.key(), iter.value().msg, iter.value().timestamp);
+            registerReceipt(val.receipt, key, val.msg, val.timestamp);
             continue;
         }
-        QString messageText = iter.value().msg->toString();
+        QString messageText = val.msg->toString();
         int rec;
-        if (iter.value().msg->isAction())
+        if (val.msg->isAction())
             rec = Core::getInstance()->sendAction(f->getFriendID(), messageText);
         else
             rec = Core::getInstance()->sendMessage(f->getFriendID(), messageText);
 
-        registerReceipt(rec, iter.key(), iter.value().msg);
+        registerReceipt(rec, key, val.msg);
     }
 }
 
diff --git a/src/video/cameradevice.cpp b/src/video/cameradevice.cpp
index ab0e6f358..ab3cb130f 100644
--- a/src/video/cameradevice.cpp
+++ b/src/video/cameradevice.cpp
@@ -40,7 +40,7 @@ QMutex CameraDevice::openDeviceLock, CameraDevice::iformatLock;
 AVInputFormat* CameraDevice::iformat{nullptr};
 AVInputFormat* CameraDevice::idesktopFormat{nullptr};
 
-CameraDevice::CameraDevice(const QString devName, AVFormatContext *context)
+CameraDevice::CameraDevice(const QString &devName, AVFormatContext *context)
     : devName{devName}, context{context}, refcount{1}
 {
 }
diff --git a/src/video/cameradevice.h b/src/video/cameradevice.h
index edf50549d..83209aeeb 100644
--- a/src/video/cameradevice.h
+++ b/src/video/cameradevice.h
@@ -66,7 +66,7 @@ public:
     static QString getDefaultDeviceName();
 
 private:
-    CameraDevice(const QString devName, AVFormatContext *context);
+    CameraDevice(const QString &devName, AVFormatContext *context);
     static CameraDevice* open(QString devName, AVDictionary** options);
     static bool getDefaultInputFormat(); ///< Sets CameraDevice::iformat, returns success/failure
     static QVector<QPair<QString, QString> > getRawDeviceListGeneric(); ///< Uses avdevice_list_devices
diff --git a/src/widget/form/tabcompleter.cpp b/src/widget/form/tabcompleter.cpp
index f5fbd921b..4c897bc1c 100644
--- a/src/widget/form/tabcompleter.cpp
+++ b/src/widget/form/tabcompleter.cpp
@@ -91,7 +91,7 @@ void TabCompleter::complete()
 
         // remember charcount to delete next time and advance to next completion
         lastCompletionLength = nextCompletion->length();
-        nextCompletion++;
+        ++nextCompletion;
 
         // we're completing the first word of the line
         if (msgEdit->textCursor().position() == lastCompletionLength)
diff --git a/src/widget/maskablepixmapwidget.cpp b/src/widget/maskablepixmapwidget.cpp
index 958d3af52..bb2bf8fa9 100644
--- a/src/widget/maskablepixmapwidget.cpp
+++ b/src/widget/maskablepixmapwidget.cpp
@@ -81,7 +81,7 @@ void MaskablePixmapWidget::setClickable(bool clickable)
         unsetCursor();
 }
 
-void MaskablePixmapWidget::setPixmap(const QPixmap &pmap, QColor background)
+void MaskablePixmapWidget::setPixmap(const QPixmap &pmap, const QColor &background)
 {
     if (!pmap.isNull())
     {
diff --git a/src/widget/maskablepixmapwidget.h b/src/widget/maskablepixmapwidget.h
index 590d8f976..9cfad272e 100644
--- a/src/widget/maskablepixmapwidget.h
+++ b/src/widget/maskablepixmapwidget.h
@@ -30,7 +30,7 @@ public:
     ~MaskablePixmapWidget();
     void autopickBackground();
     void setClickable(bool clickable);
-    void setPixmap(const QPixmap &pmap, QColor background);
+    void setPixmap(const QPixmap &pmap, const QColor &background);
     void setPixmap(const QPixmap &pmap);
     QPixmap getPixmap() const;
     void setSize(QSize size);
diff --git a/src/widget/style.cpp b/src/widget/style.cpp
index 9b93b30eb..57f47a8c6 100644
--- a/src/widget/style.cpp
+++ b/src/widget/style.cpp
@@ -179,7 +179,7 @@ void Style::setThemeColor(int color)
         setThemeColor(themeColorColors[color]);
 }
 
-void Style::setThemeColor(QColor color)
+void Style::setThemeColor(const QColor &color)
 {
     if (!color.isValid())
     {
diff --git a/src/widget/style.h b/src/widget/style.h
index b3ec7361c..6b4cb236d 100644
--- a/src/widget/style.h
+++ b/src/widget/style.h
@@ -65,7 +65,7 @@ public:
     static QString resolve(QString qss);
     static void repolish(QWidget* w);
     static void setThemeColor(int color);
-    static void setThemeColor(QColor color); ///< Pass an invalid QColor to reset to defaults
+    static void setThemeColor(const QColor &color); ///< Pass an invalid QColor to reset to defaults
     static void applyTheme(); ///< Reloads some CCS
     static QPixmap scaleSvgImage(const QString& path, uint32_t width, uint32_t height);
 
diff --git a/src/widget/widget.cpp b/src/widget/widget.cpp
index 410d3fd70..2400c7821 100644
--- a/src/widget/widget.cpp
+++ b/src/widget/widget.cpp
@@ -685,7 +685,7 @@ void Widget::onTransferClicked()
     }
 }
 
-void Widget::confirmExecutableOpen(const QFileInfo file)
+void Widget::confirmExecutableOpen(const QFileInfo &file)
 {
     static const QStringList dangerousExtensions = { "app", "bat", "com", "cpl", "dmg", "exe", "hta", "jar", "js", "jse", "lnk", "msc", "msh", "msh1", "msh1xml", "msh2", "msh2xml", "mshxml", "msi", "msp", "pif", "ps1", "ps1xml", "ps2", "ps2xml", "psc1", "psc2", "py", "reg", "scf", "sh", "src", "vb", "vbe", "vbs", "ws", "wsc", "wsf", "wsh" };
 
diff --git a/src/widget/widget.h b/src/widget/widget.h
index b26084c16..c92eb869b 100644
--- a/src/widget/widget.h
+++ b/src/widget/widget.h
@@ -85,7 +85,7 @@ public:
     ContentDialog* createContentDialog() const;
     ContentLayout* createContentDialog(DialogType type);
 
-    static void confirmExecutableOpen(const QFileInfo file);
+    static void confirmExecutableOpen(const QFileInfo &file);
 
     void clearAllReceipts();
     void reloadHistory();