diff --git a/src/kmreaderwin.h b/src/kmreaderwin.h
index 261715346..61139832f 100644
--- a/src/kmreaderwin.h
+++ b/src/kmreaderwin.h
@@ -220,8 +220,8 @@ private:
 private:
     KContacts::Addressee mSearchedAddress;
     Akonadi::Item mSearchedContact;
-    QWidget *mMainWindow = nullptr;
-    KActionCollection *mActionCollection = nullptr;
+    QWidget *const mMainWindow;
+    KActionCollection *const mActionCollection;
 
     QAction *mMailToComposeAction = nullptr;
     QAction *mMailToReplyAction = nullptr;
diff --git a/src/manageshowcollectionproperties.h b/src/manageshowcollectionproperties.h
index 312592528..9c8d137f0 100644
--- a/src/manageshowcollectionproperties.h
+++ b/src/manageshowcollectionproperties.h
@@ -41,7 +41,7 @@ private:
 
     QHash<Akonadi::Collection::Id, QPointer<Akonadi::CollectionPropertiesDialog> > mHashDialogBox;
     QStringList mPages;
-    KMMainWidget *mMainWidget = nullptr;
+    KMMainWidget *const mMainWidget;
 };
 
 #endif // MANAGESHOWCOLLECTIONPROPERTIES_H
diff --git a/src/messageactions.h b/src/messageactions.h
index b41aaeea1..0d1b7f2ac 100644
--- a/src/messageactions.h
+++ b/src/messageactions.h
@@ -138,7 +138,7 @@ private:
     QList<QAction *> mMailListActionList;
     Akonadi::Item mCurrentItem;
     Akonadi::Item::List mVisibleItems;
-    QWidget *mParent = nullptr;
+    QWidget *const mParent;
     KMReaderWin *mMessageView = nullptr;
 
     KActionMenu *mReplyActionMenu = nullptr;
diff --git a/src/unityservicemanager.h b/src/unityservicemanager.h
index 30c013ecf..136831e29 100644
--- a/src/unityservicemanager.h
+++ b/src/unityservicemanager.h
@@ -36,7 +36,7 @@ private:
     void slotCollectionStatisticsChanged(Akonadi::Collection::Id id, const Akonadi::CollectionStatistics &);
     void initUnity();
     Q_REQUIRED_RESULT bool hasUnreadMail() const;
-    QDBusServiceWatcher *mUnityServiceWatcher = nullptr;
+    QDBusServiceWatcher *const mUnityServiceWatcher;
     KMail::KMSystemTray *mSystemTray = nullptr;
     int mCount = 0;
     bool mUnityServiceAvailable = false;