diff --git a/quicksettings/nightcolor/nightcolorutil.cpp b/quicksettings/nightcolor/nightcolorutil.cpp
index a1d6e92a..1e54f67d 100644
--- a/quicksettings/nightcolor/nightcolorutil.cpp
+++ b/quicksettings/nightcolor/nightcolorutil.cpp
@@ -40,7 +40,7 @@ void NightColorUtil::setEnabled(bool enabled)
     m_settings->save();
 }
 
-void NightColorUtil::enabledUpdated(QString name, QVariantMap map, QStringList list)
+void NightColorUtil::enabledUpdated(const QString &name, const QVariantMap &map, const QStringList &list)
 {
     Q_UNUSED(name);
     Q_UNUSED(map);
diff --git a/quicksettings/nightcolor/nightcolorutil.h b/quicksettings/nightcolor/nightcolorutil.h
index 25c4817f..2da9b3bc 100644
--- a/quicksettings/nightcolor/nightcolorutil.h
+++ b/quicksettings/nightcolor/nightcolorutil.h
@@ -26,10 +26,10 @@ Q_SIGNALS:
     void enabledChanged();
 
 public Q_SLOTS:
-    void enabledUpdated(QString name, QVariantMap map, QStringList list);
+    void enabledUpdated(const QString &name, const QVariantMap &map, const QStringList &list);
 
 private:
     bool m_enabled;
     OrgKdeKwinColorCorrectInterface *m_ccInterface;
-    NightColorSettings *m_settings;
+    NightColorSettings *const m_settings;
 };