Init variables where they are declared when possible (clang-tidy)

clang-tidy -p compile_commands.json $file \
    -checks='-*,modernize-use-default-member-init,readability-redundant-member-init' \
    -config='{CheckOptions: [{key: modernize-use-default-member-init.UseAssignment, value: "1"}]}' \
    -header-filter='qtwayland' \
    -fix

Afterwards I ran search and replace on the diff to clean up some whitespace errors:

- Replaced '(\n\+[^:\n]*)(:\s+\+\s+)' with '$1: '
- Replaced '(\n\+[^,\n]*)(,\s+\+\s+)' with '$1, '
- Replaced '\n\+\s*\n' with '\n'

I also had to do some manual edits, because for some reason, this particular
clang-tidy check doesn't trigger for some files.

Change-Id: I3b3909bac4bf20108bbe8ad1e01bcc54236dae1b
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

169 files changed, 385 insertions, 841 deletions

diff --git a/examples/wayland/custom-extension/client-common/customextension.cpp b/examples/wayland/custom-extension/client-common/customextension.cpp
index 41b4a30e9..90e1f4377 100644
--- a/examples/wayland/custom-extension/client-common/customextension.cpp
+++ b/examples/wayland/custom-extension/client-common/customextension.cpp
@@ -61,7 +61,6 @@ QT_BEGIN_NAMESPACE
 
 CustomExtension::CustomExtension()
     : QWaylandClientExtensionTemplate(/* Supported protocol version */ 1 )
-    , m_activated(false)
 {
     connect(this, &CustomExtension::activeChanged, this, &CustomExtension::handleExtensionActive);
 }
diff --git a/examples/wayland/custom-extension/client-common/customextension.h b/examples/wayland/custom-extension/client-common/customextension.h
index 003a5a008..5e48ea75e 100644
--- a/examples/wayland/custom-extension/client-common/customextension.h
+++ b/examples/wayland/custom-extension/client-common/customextension.h
@@ -93,7 +93,7 @@ private:
     void sendWindowRegistration(QWindow *);
 
     QList<QWindow *> m_windows;
-    bool m_activated;
+    bool m_activated = false;
 };
 
 class CustomExtensionObject : public QWaylandClientExtensionTemplate<CustomExtensionObject>
diff --git a/examples/wayland/minimal-cpp/compositor.cpp b/examples/wayland/minimal-cpp/compositor.cpp
index 52c2c2326..d32d8e888 100644
--- a/examples/wayland/minimal-cpp/compositor.cpp
+++ b/examples/wayland/minimal-cpp/compositor.cpp
@@ -66,8 +66,7 @@ bool View::isCursor() const
 }
 
 Compositor::Compositor(Window *window)
-    : QWaylandCompositor()
-    , m_window(window)
+    : m_window(window)
 {
 }
 
diff --git a/examples/wayland/minimal-cpp/compositor.h b/examples/wayland/minimal-cpp/compositor.h
index 76af25ecb..9dd5cb2f0 100644
--- a/examples/wayland/minimal-cpp/compositor.h
+++ b/examples/wayland/minimal-cpp/compositor.h
@@ -64,12 +64,12 @@ class View : public QWaylandView
 {
     Q_OBJECT
 public:
-    View() : m_texture(nullptr) {}
+    View() {}
     QOpenGLTexture *getTexture();
     bool isCursor() const;
 private:
     friend class Compositor;
-    QOpenGLTexture *m_texture;
+    QOpenGLTexture *m_texture = nullptr;
 };
 
 class Compositor : public QWaylandCompositor
diff --git a/examples/wayland/minimal-cpp/window.cpp b/examples/wayland/minimal-cpp/window.cpp
index 9de81e5f4..b84806472 100644
--- a/examples/wayland/minimal-cpp/window.cpp
+++ b/examples/wayland/minimal-cpp/window.cpp
@@ -58,7 +58,6 @@
 #include <QRandomGenerator>
 
 Window::Window()
-    : m_compositor(nullptr)
 {
 }
 
diff --git a/examples/wayland/minimal-cpp/window.h b/examples/wayland/minimal-cpp/window.h
index 5396da15c..2a7a1109a 100644
--- a/examples/wayland/minimal-cpp/window.h
+++ b/examples/wayland/minimal-cpp/window.h
@@ -70,7 +70,7 @@ protected:
 
 private:
     QOpenGLTextureBlitter m_textureBlitter;
-    Compositor *m_compositor;
+    Compositor *m_compositor = nullptr;
 };
 
 QT_END_NAMESPACE
diff --git a/examples/wayland/qwindow-compositor/compositor.cpp b/examples/wayland/qwindow-compositor/compositor.cpp
index 11516a182..8ba8929e1 100644
--- a/examples/wayland/qwindow-compositor/compositor.cpp
+++ b/examples/wayland/qwindow-compositor/compositor.cpp
@@ -68,13 +68,6 @@
 
 View::View(Compositor *compositor)
     : m_compositor(compositor)
-    , m_textureTarget(GL_TEXTURE_2D)
-    , m_texture(nullptr)
-    , m_wlShellSurface(nullptr)
-    , m_xdgSurface(nullptr)
-    , m_xdgPopup(nullptr)
-    , m_parentView(nullptr)
-    , m_animationFactor(1.0)
 {}
 
 QOpenGLTexture *View::getTexture()
@@ -190,8 +183,7 @@ void View::onXdgUnsetFullscreen()
 }
 
 Compositor::Compositor(QWindow *window)
-    : QWaylandCompositor()
-    , m_window(window)
+    : m_window(window)
     , m_wlShell(new QWaylandWlShell(this))
     , m_xdgShell(new QWaylandXdgShellV5(this))
 {
diff --git a/examples/wayland/qwindow-compositor/compositor.h b/examples/wayland/qwindow-compositor/compositor.h
index b0fc0c84e..d1b501ff8 100644
--- a/examples/wayland/qwindow-compositor/compositor.h
+++ b/examples/wayland/qwindow-compositor/compositor.h
@@ -96,18 +96,18 @@ protected:
 
 private:
     friend class Compositor;
-    Compositor *m_compositor;
-    GLenum m_textureTarget;
-    QOpenGLTexture *m_texture;
+    Compositor *m_compositor = nullptr;
+    GLenum m_textureTarget = GL_TEXTURE_2D;
+    QOpenGLTexture *m_texture = nullptr;
     QOpenGLTextureBlitter::Origin m_origin;
     QPointF m_position;
     QSize m_size;
-    QWaylandWlShellSurface *m_wlShellSurface;
-    QWaylandXdgSurfaceV5 *m_xdgSurface;
-    QWaylandXdgPopupV5 *m_xdgPopup;
-    View *m_parentView;
+    QWaylandWlShellSurface *m_wlShellSurface = nullptr;
+    QWaylandXdgSurfaceV5 *m_xdgSurface = nullptr;
+    QWaylandXdgPopupV5 *m_xdgPopup = nullptr;
+    View *m_parentView = nullptr;
     QPoint m_offset;
-    qreal m_animationFactor;
+    qreal m_animationFactor = 1.0;
     QBasicTimer m_animationTimer;
     bool m_animationCountUp;
 
diff --git a/examples/wayland/qwindow-compositor/window.cpp b/examples/wayland/qwindow-compositor/window.cpp
index 9d5b4395e..80aeec4c3 100644
--- a/examples/wayland/qwindow-compositor/window.cpp
+++ b/examples/wayland/qwindow-compositor/window.cpp
@@ -60,10 +60,6 @@
 #include <QtWaylandCompositor/qwaylandseat.h>
 
 Window::Window()
-    : m_backgroundTexture(nullptr)
-    , m_compositor(nullptr)
-    , m_grabState(NoGrab)
-    , m_dragIconView(nullptr)
 {
 }
 
diff --git a/examples/wayland/qwindow-compositor/window.h b/examples/wayland/qwindow-compositor/window.h
index d11553151..c16e726bf 100644
--- a/examples/wayland/qwindow-compositor/window.h
+++ b/examples/wayland/qwindow-compositor/window.h
@@ -96,17 +96,17 @@ private:
 
     QOpenGLTextureBlitter m_textureBlitter;
     QSize m_backgroundImageSize;
-    QOpenGLTexture *m_backgroundTexture;
-    Compositor *m_compositor;
+    QOpenGLTexture *m_backgroundTexture = nullptr;
+    Compositor *m_compositor = nullptr;
     QPointer<View> m_mouseView;
-    GrabState m_grabState;
+    GrabState m_grabState = NoGrab;
     QSize m_initialSize;
     int m_resizeEdge;
     bool m_resizeAnchored;
     QPointF m_resizeAnchorPosition;
     QPointF m_mouseOffset;
     QPointF m_initialMousePos;
-    View *m_dragIconView;
+    View *m_dragIconView = nullptr;
 };
 
 QT_END_NAMESPACE
diff --git a/examples/wayland/server-buffer/compositor/sharebufferextension.cpp b/examples/wayland/server-buffer/compositor/sharebufferextension.cpp
index 8277dad34..71731ed22 100644
--- a/examples/wayland/server-buffer/compositor/sharebufferextension.cpp
+++ b/examples/wayland/server-buffer/compositor/sharebufferextension.cpp
@@ -61,8 +61,6 @@
 
 ShareBufferExtension::ShareBufferExtension(QWaylandCompositor *compositor)
     : QWaylandCompositorExtensionTemplate(compositor)
-    , m_server_buffer_integration(nullptr)
-    , m_server_buffers_created(false)
 {
 }
 
diff --git a/examples/wayland/server-buffer/compositor/sharebufferextension.h b/examples/wayland/server-buffer/compositor/sharebufferextension.h
index f84d9c4df..4719844b3 100644
--- a/examples/wayland/server-buffer/compositor/sharebufferextension.h
+++ b/examples/wayland/server-buffer/compositor/sharebufferextension.h
@@ -89,8 +89,8 @@ protected:
 private:
     void createServerBuffers();
     QList<QtWayland::ServerBuffer *> m_server_buffers;
-    QtWayland::ServerBufferIntegration *m_server_buffer_integration;
-    bool m_server_buffers_created;
+    QtWayland::ServerBufferIntegration *m_server_buffer_integration = nullptr;
+    bool m_server_buffers_created = false;
 };
 
 Q_COMPOSITOR_DECLARE_QUICK_EXTENSION_CLASS(ShareBufferExtension)
diff --git a/examples/wayland/server-buffer/cpp-client/main.cpp b/examples/wayland/server-buffer/cpp-client/main.cpp
index b0b3712b9..7ff34072b 100644
--- a/examples/wayland/server-buffer/cpp-client/main.cpp
+++ b/examples/wayland/server-buffer/cpp-client/main.cpp
@@ -73,7 +73,6 @@ class TestWindow : public QOpenGLWindow
 
 public:
     TestWindow()
-        : m_extension(nullptr)
     {
         m_extension = new ShareBufferExtension;
         connect(m_extension, SIGNAL(bufferReceived(QtWaylandClient::QWaylandServerBuffer*)), this, SLOT(receiveBuffer(QtWaylandClient::QWaylandServerBuffer*)));
@@ -118,7 +117,7 @@ protected:
 private:
 
     QOpenGLTextureBlitter *m_blitter;
-    ShareBufferExtension *m_extension;
+    ShareBufferExtension *m_extension = nullptr;
     QList<QtWaylandClient::QWaylandServerBuffer*> m_buffers;
 
 };
diff --git a/src/client/global/qwaylandclientextension.cpp b/src/client/global/qwaylandclientextension.cpp
index 60a8944f8..125b1e19d 100644
--- a/src/client/global/qwaylandclientextension.cpp
+++ b/src/client/global/qwaylandclientextension.cpp
@@ -49,10 +49,6 @@
 QT_BEGIN_NAMESPACE
 
 QWaylandClientExtensionPrivate::QWaylandClientExtensionPrivate()
-    : QObjectPrivate()
-    , waylandIntegration(nullptr)
-    , version(-1)
-    , active(false)
 {
     // Keep the possibility to use a custom waylandIntegration as a plugin,
     // but also add the possibility to run it as a QML component.
diff --git a/src/client/global/qwaylandclientextension_p.h b/src/client/global/qwaylandclientextension_p.h
index 0fd59b3f7..69cc46a0a 100644
--- a/src/client/global/qwaylandclientextension_p.h
+++ b/src/client/global/qwaylandclientextension_p.h
@@ -65,16 +65,15 @@ public:
     static void handleRegistryGlobal(void *data, ::wl_registry *registry, uint32_t id,
                                      const QString &interface, uint32_t version);
 
-    QtWaylandClient::QWaylandIntegration *waylandIntegration;
-    int version;
-    bool active;
+    QtWaylandClient::QWaylandIntegration *waylandIntegration = nullptr;
+    int version = -1;
+    bool active = false;
 };
 
 class Q_WAYLAND_CLIENT_EXPORT QWaylandClientExtensionTemplatePrivate : public QWaylandClientExtensionPrivate
 {
 public:
     QWaylandClientExtensionTemplatePrivate()
-        : QWaylandClientExtensionPrivate()
     { }
 };
 
diff --git a/src/client/hardwareintegration/qwaylandserverbufferintegration.cpp b/src/client/hardwareintegration/qwaylandserverbufferintegration.cpp
index 013ddae9f..d966a1919 100644
--- a/src/client/hardwareintegration/qwaylandserverbufferintegration.cpp
+++ b/src/client/hardwareintegration/qwaylandserverbufferintegration.cpp
@@ -44,7 +44,6 @@ QT_BEGIN_NAMESPACE
 namespace QtWaylandClient {
 
 QWaylandServerBuffer::QWaylandServerBuffer()
-    : m_user_data(nullptr)
 {
 }
 
diff --git a/src/client/hardwareintegration/qwaylandserverbufferintegration_p.h b/src/client/hardwareintegration/qwaylandserverbufferintegration_p.h
index 3b8b3a6de..7439087d8 100644
--- a/src/client/hardwareintegration/qwaylandserverbufferintegration_p.h
+++ b/src/client/hardwareintegration/qwaylandserverbufferintegration_p.h
@@ -89,7 +89,7 @@ protected:
     QSize m_size;
 
 private:
-    void *m_user_data;
+    void *m_user_data = nullptr;
 };
 
 class Q_WAYLAND_CLIENT_EXPORT QWaylandServerBufferIntegration
diff --git a/src/client/qwaylandabstractdecoration.cpp b/src/client/qwaylandabstractdecoration.cpp
index 6a7a2ef4c..c20b70e9e 100644
--- a/src/client/qwaylandabstractdecoration.cpp
+++ b/src/client/qwaylandabstractdecoration.cpp
@@ -60,21 +60,17 @@ public:
     QWaylandAbstractDecorationPrivate();
     ~QWaylandAbstractDecorationPrivate();
 
-    QWindow *m_window;
-    QWaylandWindow *m_wayland_window;
+    QWindow *m_window = nullptr;
+    QWaylandWindow *m_wayland_window = nullptr;
 
-    bool m_isDirty;
+    bool m_isDirty = true;
     QImage m_decorationContentImage;
 
-    Qt::MouseButtons m_mouseButtons;
+    Qt::MouseButtons m_mouseButtons = Qt::NoButton;
 };
 
 QWaylandAbstractDecorationPrivate::QWaylandAbstractDecorationPrivate()
-    : m_window(nullptr)
-    , m_wayland_window(nullptr)
-    , m_isDirty(true)
-    , m_decorationContentImage(nullptr)
-    , m_mouseButtons(Qt::NoButton)
+    : m_decorationContentImage(nullptr)
 {
 }
 
diff --git a/src/client/qwaylandbuffer.cpp b/src/client/qwaylandbuffer.cpp
index 2dc99b3b7..9792cdd61 100644
--- a/src/client/qwaylandbuffer.cpp
+++ b/src/client/qwaylandbuffer.cpp
@@ -47,8 +47,6 @@ QT_BEGIN_NAMESPACE
 namespace QtWaylandClient {
 
 QWaylandBuffer::QWaylandBuffer()
-              : mBuffer(nullptr)
-              , mBusy(false)
 {
 }
 
diff --git a/src/client/qwaylandbuffer_p.h b/src/client/qwaylandbuffer_p.h
index 9e8cba2e4..156ea9530 100644
--- a/src/client/qwaylandbuffer_p.h
+++ b/src/client/qwaylandbuffer_p.h
@@ -77,10 +77,10 @@ public:
     bool busy() const { return mBusy; }
 
 protected:
-    struct wl_buffer *mBuffer;
+    struct wl_buffer *mBuffer = nullptr;
 
 private:
-    bool mBusy;
+    bool mBusy = false;
 
     static void release(void *data, wl_buffer *);
     static const wl_buffer_listener listener;
diff --git a/src/client/qwaylanddatadevice.cpp b/src/client/qwaylanddatadevice.cpp
index 83912035a..4411ba65c 100644
--- a/src/client/qwaylanddatadevice.cpp
+++ b/src/client/qwaylanddatadevice.cpp
@@ -66,11 +66,6 @@ QWaylandDataDevice::QWaylandDataDevice(QWaylandDataDeviceManager *manager, QWayl
     : QtWayland::wl_data_device(manager->get_data_device(inputDevice->wl_seat()))
     , m_display(manager->display())
     , m_inputDevice(inputDevice)
-    , m_enterSerial(0)
-    , m_dragWindow(nullptr)
-    , m_dragPoint()
-    , m_dragOffer()
-    , m_selectionOffer()
 {
 }
 
diff --git a/src/client/qwaylanddatadevice_p.h b/src/client/qwaylanddatadevice_p.h
index 7fb0003b4..29461930b 100644
--- a/src/client/qwaylanddatadevice_p.h
+++ b/src/client/qwaylanddatadevice_p.h
@@ -117,9 +117,9 @@ private:
     QPoint calculateDragPosition(int x, int y, QWindow *wnd) const;
 #endif
 
-    QWaylandDisplay *m_display;
-    QWaylandInputDevice *m_inputDevice;
-    uint32_t m_enterSerial;
+    QWaylandDisplay *m_display = nullptr;
+    QWaylandInputDevice *m_inputDevice = nullptr;
+    uint32_t m_enterSerial = 0;
     QPointer<QWindow> m_dragWindow;
     QPoint m_dragPoint;
     QScopedPointer<QWaylandDataOffer> m_dragOffer;
diff --git a/src/client/qwaylanddataoffer.cpp b/src/client/qwaylanddataoffer.cpp
index 2491c658b..35085a7f0 100644
--- a/src/client/qwaylanddataoffer.cpp
+++ b/src/client/qwaylanddataoffer.cpp
@@ -87,8 +87,7 @@ void QWaylandDataOffer::data_offer_offer(const QString &mime_type)
 }
 
 QWaylandMimeData::QWaylandMimeData(QWaylandDataOffer *dataOffer, QWaylandDisplay *display)
-    : QInternalMimeData()
-    , m_dataOffer(dataOffer)
+    : m_dataOffer(dataOffer)
     , m_display(display)
 {
 }
diff --git a/src/client/qwaylanddisplay.cpp b/src/client/qwaylanddisplay.cpp
index 179c0454e..abb084522 100644
--- a/src/client/qwaylanddisplay.cpp
+++ b/src/client/qwaylanddisplay.cpp
@@ -124,20 +124,6 @@ QWaylandWindowManagerIntegration *QWaylandDisplay::windowManagerIntegration() co
 
 QWaylandDisplay::QWaylandDisplay(QWaylandIntegration *waylandIntegration)
     : mWaylandIntegration(waylandIntegration)
-#if QT_CONFIG(wayland_datadevice)
-    , mDndSelectionHandler(nullptr)
-#endif
-    , mWindowExtension(nullptr)
-    , mSubCompositor(nullptr)
-    , mTouchExtension(nullptr)
-    , mQtKeyExtension(nullptr)
-    , mTextInputManager(nullptr)
-    , mHardwareIntegration(nullptr)
-    , mLastInputSerial(0)
-    , mLastInputDevice(nullptr)
-    , mLastInputWindow(nullptr)
-    , mLastKeyboardFocus(nullptr)
-    , mSyncCallback(nullptr)
 {
     qRegisterMetaType<uint32_t>("uint32_t");
 
diff --git a/src/client/qwaylanddisplay_p.h b/src/client/qwaylanddisplay_p.h
index 35d861760..0a7ea427a 100644
--- a/src/client/qwaylanddisplay_p.h
+++ b/src/client/qwaylanddisplay_p.h
@@ -217,12 +217,12 @@ private:
     int mWritableNotificationFd;
     QList<RegistryGlobal> mGlobals;
     int mCompositorVersion;
-    uint32_t mLastInputSerial;
-    QWaylandInputDevice *mLastInputDevice;
+    uint32_t mLastInputSerial = 0;
+    QWaylandInputDevice *mLastInputDevice = nullptr;
     QPointer<QWaylandWindow> mLastInputWindow;
     QPointer<QWaylandWindow> mLastKeyboardFocus;
     QVector<QWaylandWindow *> mActiveWindows;
-    struct wl_callback *mSyncCallback;
+    struct wl_callback *mSyncCallback = nullptr;
     static const wl_callback_listener syncCallbackListener;
 
     void registry_global(uint32_t id, const QString &interface, uint32_t version) override;
diff --git a/src/client/qwaylandinputcontext.cpp b/src/client/qwaylandinputcontext.cpp
index 16ee057c5..58ad90d41 100644
--- a/src/client/qwaylandinputcontext.cpp
+++ b/src/client/qwaylandinputcontext.cpp
@@ -71,15 +71,6 @@ const Qt::InputMethodQueries supportedQueries = Qt::ImEnabled |
 QWaylandTextInput::QWaylandTextInput(QWaylandDisplay *display, struct ::zwp_text_input_v2 *text_input)
     : QtWayland::zwp_text_input_v2(text_input)
     , m_display(display)
-    , m_builder()
-    , m_serial(0)
-    , m_surface(nullptr)
-    , m_preeditCommit()
-    , m_inputPanelVisible(false)
-    , m_keyboardRectangle()
-    , m_locale()
-    , m_inputDirection(Qt::LayoutDirectionAuto)
-    , m_resetCallback(nullptr)
 {
 }
 
@@ -391,9 +382,7 @@ Qt::KeyboardModifiers QWaylandTextInput::modifiersToQtModifiers(uint32_t modifie
 }
 
 QWaylandInputContext::QWaylandInputContext(QWaylandDisplay *display)
-    : QPlatformInputContext()
-    , mDisplay(display)
-    , mCurrentWindow()
+    : mDisplay(display)
 {
 }
 
diff --git a/src/client/qwaylandinputcontext_p.h b/src/client/qwaylandinputcontext_p.h
index a131bc5bd..a554f2301 100644
--- a/src/client/qwaylandinputcontext_p.h
+++ b/src/client/qwaylandinputcontext_p.h
@@ -112,17 +112,17 @@ private:
 
     QVector<Qt::KeyboardModifier> m_modifiersMap;
 
-    uint32_t m_serial;
-    struct ::wl_surface *m_surface;
+    uint32_t m_serial = 0;
+    struct ::wl_surface *m_surface = nullptr;
 
     QString m_preeditCommit;
 
-    bool m_inputPanelVisible;
+    bool m_inputPanelVisible = false;
     QRectF m_keyboardRectangle;
     QLocale m_locale;
-    Qt::LayoutDirection m_inputDirection;
+    Qt::LayoutDirection m_inputDirection = Qt::LayoutDirectionAuto;
 
-    struct ::wl_callback *m_resetCallback;
+    struct ::wl_callback *m_resetCallback = nullptr;
     static const wl_callback_listener callbackListener;
     static void resetCallback(void *data, struct wl_callback *wl_callback, uint32_t time);
 };
diff --git a/src/client/qwaylandinputdevice.cpp b/src/client/qwaylandinputdevice.cpp
index b34504a1f..93344d13f 100644
--- a/src/client/qwaylandinputdevice.cpp
+++ b/src/client/qwaylandinputdevice.cpp
@@ -200,8 +200,7 @@ QWaylandInputDevice::Touch::~Touch()
 }
 
 QWaylandInputDevice::QWaylandInputDevice(QWaylandDisplay *display, int version, uint32_t id)
-    : QObject()
-    , QtWayland::wl_seat(display->wl_registry(), id, qMin(version, 4))
+    : QtWayland::wl_seat(display->wl_registry(), id, qMin(version, 4))
     , mQDisplay(display)
     , mDisplay(display->wl_display())
     , mVersion(qMin(version, 4))
diff --git a/src/client/qwaylandintegration.cpp b/src/client/qwaylandintegration.cpp
index 267e481ac..fe1655c9f 100644
--- a/src/client/qwaylandintegration.cpp
+++ b/src/client/qwaylandintegration.cpp
@@ -121,16 +121,11 @@ public:
 };
 
 QWaylandIntegration::QWaylandIntegration()
-    : mClientBufferIntegration(nullptr)
-    , mInputDeviceIntegration(nullptr)
-    , mFontDb(new QGenericUnixFontDatabase())
+    : mFontDb(new QGenericUnixFontDatabase())
     , mNativeInterface(new QWaylandNativeInterface(this))
 #if QT_CONFIG(accessibility)
     , mAccessibility(new QPlatformAccessibility())
 #endif
-    , mClientBufferIntegrationInitialized(false)
-    , mServerBufferIntegrationInitialized(false)
-    , mShellIntegrationInitialized(false)
 {
     initializeInputDeviceIntegration();
     mDisplay.reset(new QWaylandDisplay(this));
diff --git a/src/client/qwaylandintegration_p.h b/src/client/qwaylandintegration_p.h
index 17144b8d7..7ce79e6da 100644
--- a/src/client/qwaylandintegration_p.h
+++ b/src/client/qwaylandintegration_p.h
@@ -147,9 +147,9 @@ private:
     QScopedPointer<QPlatformAccessibility> mAccessibility;
 #endif
     bool mFailed = false;
-    bool mClientBufferIntegrationInitialized;
-    bool mServerBufferIntegrationInitialized;
-    bool mShellIntegrationInitialized;
+    bool mClientBufferIntegrationInitialized = false;
+    bool mServerBufferIntegrationInitialized = false;
+    bool mShellIntegrationInitialized = false;
 
     friend class QWaylandDisplay;
 };
diff --git a/src/client/qwaylandscreen.cpp b/src/client/qwaylandscreen.cpp
index 1c9ce23ba..38d97a91d 100644
--- a/src/client/qwaylandscreen.cpp
+++ b/src/client/qwaylandscreen.cpp
@@ -53,20 +53,10 @@ QT_BEGIN_NAMESPACE
 namespace QtWaylandClient {
 
 QWaylandScreen::QWaylandScreen(QWaylandDisplay *waylandDisplay, int version, uint32_t id)
-    : QPlatformScreen()
-    , QtWayland::wl_output(waylandDisplay->wl_registry(), id, qMin(version, 2))
+    : QtWayland::wl_output(waylandDisplay->wl_registry(), id, qMin(version, 2))
     , m_outputId(id)
     , mWaylandDisplay(waylandDisplay)
-    , mScale(1)
-    , mDepth(32)
-    , mRefreshRate(60000)
-    , mTransform(-1)
-    , mFormat(QImage::Format_ARGB32_Premultiplied)
     , mOutputName(QStringLiteral("Screen%1").arg(id))
-    , m_orientation(Qt::PrimaryOrientation)
-#if QT_CONFIG(cursor)
-    , mWaylandCursor(nullptr)
-#endif
 {
 }
 
diff --git a/src/client/qwaylandscreen_p.h b/src/client/qwaylandscreen_p.h
index 674e1a913..37c35cfff 100644
--- a/src/client/qwaylandscreen_p.h
+++ b/src/client/qwaylandscreen_p.h
@@ -116,21 +116,21 @@ private:
     void output_done() override;
 
     int m_outputId;
-    QWaylandDisplay *mWaylandDisplay;
+    QWaylandDisplay *mWaylandDisplay = nullptr;
     QString mManufacturer;
     QString mModel;
     QRect mGeometry;
-    int mScale;
-    int mDepth;
-    int mRefreshRate;
-    int mTransform;
-    QImage::Format mFormat;
+    int mScale = 1;
+    int mDepth = 32;
+    int mRefreshRate = 60000;
+    int mTransform = -1;
+    QImage::Format mFormat = QImage::Format_ARGB32_Premultiplied;
     QSize mPhysicalSize;
     QString mOutputName;
-    Qt::ScreenOrientation m_orientation;
+    Qt::ScreenOrientation m_orientation = Qt::PrimaryOrientation;
 
 #if QT_CONFIG(cursor)
-    QWaylandCursor *mWaylandCursor;
+    QWaylandCursor *mWaylandCursor = nullptr;
 #endif
 };
 
diff --git a/src/client/qwaylandshmbackingstore.cpp b/src/client/qwaylandshmbackingstore.cpp
index 24554ee44..cbfdf5157 100644
--- a/src/client/qwaylandshmbackingstore.cpp
+++ b/src/client/qwaylandshmbackingstore.cpp
@@ -72,9 +72,6 @@ Q_LOGGING_CATEGORY(logCategory, "qt.qpa.wayland.backingstore")
 
 QWaylandShmBuffer::QWaylandShmBuffer(QWaylandDisplay *display,
                      const QSize &size, QImage::Format format, int scale)
-    : QWaylandBuffer()
-    , mShmPool(nullptr)
-    , mMarginsImage(nullptr)
 {
     int stride = size.width() * 4;
     int alloc = stride * size.height();
@@ -161,9 +158,6 @@ QImage *QWaylandShmBuffer::imageInsideMargins(const QMargins &marginsIn)
 QWaylandShmBackingStore::QWaylandShmBackingStore(QWindow *window)
     : QPlatformBackingStore(window)
     , mDisplay(QWaylandScreen::waylandScreenFromWindow(window)->display())
-    , mFrontBuffer(nullptr)
-    , mBackBuffer(nullptr)
-    , mPainting(false)
 {
 
 }
diff --git a/src/client/qwaylandshmbackingstore_p.h b/src/client/qwaylandshmbackingstore_p.h
index 251368efd..628d1858b 100644
--- a/src/client/qwaylandshmbackingstore_p.h
+++ b/src/client/qwaylandshmbackingstore_p.h
@@ -79,9 +79,9 @@ public:
     QImage *imageInsideMargins(const QMargins &margins);
 private:
     QImage mImage;
-    struct wl_shm_pool *mShmPool;
+    struct wl_shm_pool *mShmPool = nullptr;
     QMargins mMargins;
-    QImage *mMarginsImage;
+    QImage *mMarginsImage = nullptr;
 };
 
 class Q_WAYLAND_CLIENT_EXPORT QWaylandShmBackingStore : public QPlatformBackingStore
@@ -115,11 +115,11 @@ private:
     void updateDecorations();
     QWaylandShmBuffer *getBuffer(const QSize &size);
 
-    QWaylandDisplay *mDisplay;
+    QWaylandDisplay *mDisplay = nullptr;
     QLinkedList<QWaylandShmBuffer *> mBuffers;
-    QWaylandShmBuffer *mFrontBuffer;
-    QWaylandShmBuffer *mBackBuffer;
-    bool mPainting;
+    QWaylandShmBuffer *mFrontBuffer = nullptr;
+    QWaylandShmBuffer *mBackBuffer = nullptr;
+    bool mPainting = false;
     QMutex mMutex;
 
     QSize mRequestedSize;
diff --git a/src/client/qwaylandsubsurface.cpp b/src/client/qwaylandsubsurface.cpp
index 36fdd1c7a..2ff966cbc 100644
--- a/src/client/qwaylandsubsurface.cpp
+++ b/src/client/qwaylandsubsurface.cpp
@@ -51,7 +51,6 @@ QWaylandSubSurface::QWaylandSubSurface(QWaylandWindow *window, QWaylandWindow *p
     : QtWayland::wl_subsurface(sub_surface)
     , m_window(window)
     , m_parent(parent)
-    , m_synchronized(false)
 {
     m_parent->mChildren << this;
     setDeSync();
diff --git a/src/client/qwaylandsubsurface_p.h b/src/client/qwaylandsubsurface_p.h
index 00fb8d8ed..36a92a755 100644
--- a/src/client/qwaylandsubsurface_p.h
+++ b/src/client/qwaylandsubsurface_p.h
@@ -88,7 +88,7 @@ private:
     void set_desync();
     QWaylandWindow *m_window;
     QWaylandWindow *m_parent;
-    bool m_synchronized;
+    bool m_synchronized = false;
     QMutex m_syncLock;
 
 };
diff --git a/src/client/qwaylandwindow.cpp b/src/client/qwaylandwindow.cpp
index 75dfaa499..52461dc38 100644
--- a/src/client/qwaylandwindow.cpp
+++ b/src/client/qwaylandwindow.cpp
@@ -78,25 +78,9 @@ namespace QtWaylandClient {
 QWaylandWindow *QWaylandWindow::mMouseGrab = nullptr;
 
 QWaylandWindow::QWaylandWindow(QWindow *window)
-    : QObject()
-    , QPlatformWindow(window)
+    : QPlatformWindow(window)
     , mDisplay(waylandScreen()->display())
-    , mShellSurface(nullptr)
-    , mSubSurfaceWindow(nullptr)
-    , mWindowDecoration(nullptr)
-    , mMouseEventsInContentArea(false)
-    , mMousePressedInContentArea(Qt::NoButton)
-    , mWaitingForFrameSync(false)
-    , mRequestResizeSent(false)
-    , mCanResize(true)
-    , mResizeDirty(false)
     , mResizeAfterSwap(qEnvironmentVariableIsSet("QT_WAYLAND_RESIZE_AFTER_SWAP"))
-    , mSentInitialResize(false)
-    , mScale(1)
-    , mState(Qt::WindowNoState)
-    , mMask()
-    , mBackingStore(nullptr)
-    , mUpdateRequested(false)
 {
     static WId id = 1;
     mWindowId = id++;
diff --git a/src/client/qwaylandwindow_p.h b/src/client/qwaylandwindow_p.h
index fca96f30d..a74f18827 100644
--- a/src/client/qwaylandwindow_p.h
+++ b/src/client/qwaylandwindow_p.h
@@ -81,9 +81,6 @@ class Q_WAYLAND_CLIENT_EXPORT QWaylandWindowConfigure
 {
 public:
     QWaylandWindowConfigure()
-        : width(0)
-        , height(0)
-        , edges(0)
     { }
 
     void clear()
@@ -92,9 +89,9 @@ public:
     bool isEmpty() const
     { return !height || !width; }
 
-    int width;
-    int height;
-    uint32_t edges;
+    int width = 0;
+    int height = 0;
+    uint32_t edges = 0;
 };
 
 class Q_WAYLAND_CLIENT_EXPORT QWaylandWindow : public QObject, public QPlatformWindow, public QtWayland::wl_surface
@@ -214,39 +211,39 @@ protected:
     void surface_leave(struct ::wl_output *output) override;
 
     QVector<QWaylandScreen *> mScreens; //As seen by wl_surface.enter/leave events. Chronological order.
-    QWaylandDisplay *mDisplay;
-    QWaylandShellSurface *mShellSurface;
-    QWaylandSubSurface *mSubSurfaceWindow;
+    QWaylandDisplay *mDisplay = nullptr;
+    QWaylandShellSurface *mShellSurface = nullptr;
+    QWaylandSubSurface *mSubSurfaceWindow = nullptr;
     QVector<QWaylandSubSurface *> mChildren;
 
-    QWaylandAbstractDecoration *mWindowDecoration;
-    bool mMouseEventsInContentArea;
-    Qt::MouseButtons mMousePressedInContentArea;
+    QWaylandAbstractDecoration *mWindowDecoration = nullptr;
+    bool mMouseEventsInContentArea = false;
+    Qt::MouseButtons mMousePressedInContentArea = Qt::NoButton;
 
     WId mWindowId;
-    bool mWaitingForFrameSync;
+    bool mWaitingForFrameSync = false;
     struct ::wl_callback *mFrameCallback = nullptr;
     QWaitCondition mFrameSyncWait;
 
     QMutex mResizeLock;
     QWaylandWindowConfigure mConfigure;
-    bool mRequestResizeSent;
-    bool mCanResize;
-    bool mResizeDirty;
+    bool mRequestResizeSent = false;
+    bool mCanResize = true;
+    bool mResizeDirty = false;
     bool mResizeAfterSwap;
     QVariantMap m_properties;
 
-    bool mSentInitialResize;
+    bool mSentInitialResize = false;
     QPoint mOffset;
-    int mScale;
+    int mScale = 1;
 
     QIcon mWindowIcon;
 
-    Qt::WindowStates mState;
+    Qt::WindowStates mState = Qt::WindowNoState;
     Qt::WindowFlags mFlags;
     QRegion mMask;
 
-    QWaylandShmBackingStore *mBackingStore;
+    QWaylandShmBackingStore *mBackingStore = nullptr;
 
 private slots:
     void handleScreenRemoved(QScreen *qScreen);
@@ -266,7 +263,7 @@ private:
     void handleMouseEventWithDecoration(QWaylandInputDevice *inputDevice, const QWaylandPointerEvent &e);
     void handleScreenChanged();
 
-    bool mUpdateRequested;
+    bool mUpdateRequested = false;
 
     static const wl_callback_listener callbackListener;
     static void frameCallback(void *data, struct wl_callback *wl_callback, uint32_t time);
diff --git a/src/client/qwaylandwindowmanagerintegration.cpp b/src/client/qwaylandwindowmanagerintegration.cpp
index c519126e5..785a0a44d 100644
--- a/src/client/qwaylandwindowmanagerintegration.cpp
+++ b/src/client/qwaylandwindowmanagerintegration.cpp
@@ -60,16 +60,14 @@ namespace QtWaylandClient {
 class QWaylandWindowManagerIntegrationPrivate {
 public:
     QWaylandWindowManagerIntegrationPrivate(QWaylandDisplay *waylandDisplay);
-    bool m_blockPropertyUpdates;
+    bool m_blockPropertyUpdates = false;
     QWaylandDisplay *m_waylandDisplay;
     QHash<QWindow*, QVariantMap> m_queuedProperties;
-    bool m_showIsFullScreen;
+    bool m_showIsFullScreen = false;
 };
 
 QWaylandWindowManagerIntegrationPrivate::QWaylandWindowManagerIntegrationPrivate(QWaylandDisplay *waylandDisplay)
-    : m_blockPropertyUpdates(false)
-    , m_waylandDisplay(waylandDisplay)
-    , m_showIsFullScreen(false)
+    : m_waylandDisplay(waylandDisplay)
 {
 
 }
diff --git a/src/client/qwaylandwlshellintegration.cpp b/src/client/qwaylandwlshellintegration.cpp
index e51637108..81c46be29 100644
--- a/src/client/qwaylandwlshellintegration.cpp
+++ b/src/client/qwaylandwlshellintegration.cpp
@@ -55,7 +55,6 @@ QWaylandWlShellIntegration *QWaylandWlShellIntegration::create(QWaylandDisplay *
 }
 
 QWaylandWlShellIntegration::QWaylandWlShellIntegration(QWaylandDisplay *display)
-    : m_wlShell(nullptr)
 {
     Q_FOREACH (QWaylandDisplay::RegistryGlobal global, display->globals()) {
         if (global.interface == QLatin1String("wl_shell")) {
diff --git a/src/client/qwaylandwlshellintegration_p.h b/src/client/qwaylandwlshellintegration_p.h
index 2e3ac3cc1..7a6b53524 100644
--- a/src/client/qwaylandwlshellintegration_p.h
+++ b/src/client/qwaylandwlshellintegration_p.h
@@ -70,7 +70,7 @@ public:
 private:
     QWaylandWlShellIntegration(QWaylandDisplay* display);
 
-    QtWayland::wl_shell *m_wlShell;
+    QtWayland::wl_shell *m_wlShell = nullptr;
 };
 
 }
diff --git a/src/client/qwaylandwlshellsurface.cpp b/src/client/qwaylandwlshellsurface.cpp
index 7c8d51721..00b070f3f 100644
--- a/src/client/qwaylandwlshellsurface.cpp
+++ b/src/client/qwaylandwlshellsurface.cpp
@@ -56,9 +56,6 @@ QWaylandWlShellSurface::QWaylandWlShellSurface(struct ::wl_shell_surface *shell_
     : QWaylandShellSurface(window)
     , QtWayland::wl_shell_surface(shell_surface)
     , m_window(window)
-    , m_maximized(false)
-    , m_fullscreen(false)
-    , m_extendedWindow(nullptr)
 {
     if (window->display()->windowExtension())
         m_extendedWindow = new QWaylandExtendedSurface(window);
diff --git a/src/client/qwaylandwlshellsurface_p.h b/src/client/qwaylandwlshellsurface_p.h
index 62583949b..708c6f113 100644
--- a/src/client/qwaylandwlshellsurface_p.h
+++ b/src/client/qwaylandwlshellsurface_p.h
@@ -105,10 +105,10 @@ private:
     void setPopup(QWaylandWindow *parent, QWaylandInputDevice *device, uint serial);
 
     QWaylandWindow *m_window;
-    bool m_maximized;
-    bool m_fullscreen;
+    bool m_maximized = false;
+    bool m_fullscreen = false;
     QSize m_size;
-    QWaylandExtendedSurface *m_extendedWindow;
+    QWaylandExtendedSurface *m_extendedWindow = nullptr;
 
     void shell_surface_ping(uint32_t serial) override;
     void shell_surface_configure(uint32_t edges,
diff --git a/src/client/qwaylandxdgpopup.cpp b/src/client/qwaylandxdgpopup.cpp
index d5fc49693..46a12a828 100644
--- a/src/client/qwaylandxdgpopup.cpp
+++ b/src/client/qwaylandxdgpopup.cpp
@@ -50,7 +50,6 @@ namespace QtWaylandClient {
 QWaylandXdgPopup::QWaylandXdgPopup(struct ::xdg_popup *popup, QWaylandWindow *window)
     : QWaylandShellSurface(window)
     , QtWayland::xdg_popup(popup)
-    , m_extendedWindow(nullptr)
     , m_window(window)
 {
     if (window->display()->windowExtension())
diff --git a/src/client/qwaylandxdgpopup_p.h b/src/client/qwaylandxdgpopup_p.h
index f45e717a9..85bd589bf 100644
--- a/src/client/qwaylandxdgpopup_p.h
+++ b/src/client/qwaylandxdgpopup_p.h
@@ -80,7 +80,7 @@ protected:
     void xdg_popup_popup_done() override;
 
 private:
-    QWaylandExtendedSurface *m_extendedWindow;
+    QWaylandExtendedSurface *m_extendedWindow = nullptr;
     QWaylandWindow *m_window;
 };
 
diff --git a/src/client/qwaylandxdgshell.cpp b/src/client/qwaylandxdgshell.cpp
index 6a9930608..8b252b953 100644
--- a/src/client/qwaylandxdgshell.cpp
+++ b/src/client/qwaylandxdgshell.cpp
@@ -54,13 +54,11 @@ namespace QtWaylandClient {
 
 QWaylandXdgShell::QWaylandXdgShell(struct ::xdg_shell *shell)
     : QtWayland::xdg_shell(shell)
-    , m_popupSerial(0)
 {
 }
 
 QWaylandXdgShell::QWaylandXdgShell(struct ::wl_registry *registry, uint32_t id)
     : QtWayland::xdg_shell(registry, id, 1)
-    , m_popupSerial(0)
 {
     use_unstable_version(QtWayland::xdg_shell::version_current);
 }
diff --git a/src/client/qwaylandxdgshell_p.h b/src/client/qwaylandxdgshell_p.h
index f462f2828..e01104cad 100644
--- a/src/client/qwaylandxdgshell_p.h
+++ b/src/client/qwaylandxdgshell_p.h
@@ -85,7 +85,7 @@ private:
     void xdg_shell_ping(uint32_t serial) override;
 
     QVector<QWaylandWindow *> m_popups;
-    uint m_popupSerial;
+    uint m_popupSerial = 0;
 };
 
 QT_END_NAMESPACE
diff --git a/src/client/qwaylandxdgshellintegration.cpp b/src/client/qwaylandxdgshellintegration.cpp
index 7c40d2dd7..5fa4385d6 100644
--- a/src/client/qwaylandxdgshellintegration.cpp
+++ b/src/client/qwaylandxdgshellintegration.cpp
@@ -57,7 +57,6 @@ QWaylandXdgShellIntegration *QWaylandXdgShellIntegration::create(QWaylandDisplay
 }
 
 QWaylandXdgShellIntegration::QWaylandXdgShellIntegration(QWaylandDisplay *display)
-    : m_xdgShell(nullptr)
 {
     Q_FOREACH (QWaylandDisplay::RegistryGlobal global, display->globals()) {
         if (global.interface == QLatin1String("xdg_shell")) {
diff --git a/src/client/qwaylandxdgshellintegration_p.h b/src/client/qwaylandxdgshellintegration_p.h
index cc4493e3e..ed307a5de 100644
--- a/src/client/qwaylandxdgshellintegration_p.h
+++ b/src/client/qwaylandxdgshellintegration_p.h
@@ -72,7 +72,7 @@ public:
 private:
     QWaylandXdgShellIntegration(QWaylandDisplay *display);
 
-    QWaylandXdgShell *m_xdgShell;
+    QWaylandXdgShell *m_xdgShell = nullptr;
 };
 
 }
diff --git a/src/client/qwaylandxdgshellv6.cpp b/src/client/qwaylandxdgshellv6.cpp
index 1a60d6533..69bbf55b8 100644
--- a/src/client/qwaylandxdgshellv6.cpp
+++ b/src/client/qwaylandxdgshellv6.cpp
@@ -117,9 +117,6 @@ QWaylandXdgSurfaceV6::QWaylandXdgSurfaceV6(QWaylandXdgShellV6 *shell, ::zxdg_sur
                     , zxdg_surface_v6(surface)
                     , m_shell(shell)
                     , m_window(window)
-                    , m_toplevel(nullptr)
-                    , m_popup(nullptr)
-                    , m_configured(false)
 {
 }
 
diff --git a/src/client/qwaylandxdgshellv6_p.h b/src/client/qwaylandxdgshellv6_p.h
index 769f19837..122beed0c 100644
--- a/src/client/qwaylandxdgshellv6_p.h
+++ b/src/client/qwaylandxdgshellv6_p.h
@@ -125,9 +125,9 @@ private:
 
     QWaylandXdgShellV6 *m_shell;
     QWaylandWindow *m_window;
-    Toplevel *m_toplevel;
-    Popup *m_popup;
-    bool m_configured;
+    Toplevel *m_toplevel = nullptr;
+    Popup *m_popup = nullptr;
+    bool m_configured = false;
     QRegion m_exposeRegion;
 };
 
diff --git a/src/client/qwaylandxdgshellv6integration.cpp b/src/client/qwaylandxdgshellv6integration.cpp
index a3dca70bf..cb82354b6 100644
--- a/src/client/qwaylandxdgshellv6integration.cpp
+++ b/src/client/qwaylandxdgshellv6integration.cpp
@@ -51,7 +51,6 @@ QT_BEGIN_NAMESPACE
 namespace QtWaylandClient {
 
 QWaylandXdgShellV6Integration::QWaylandXdgShellV6Integration(QWaylandDisplay *display)
-    : m_xdgShell(nullptr)
 {
     for (QWaylandDisplay::RegistryGlobal global : display->globals()) {
         if (global.interface == QLatin1String("zxdg_shell_v6")) {
diff --git a/src/client/qwaylandxdgshellv6integration_p.h b/src/client/qwaylandxdgshellv6integration_p.h
index f22b6a66a..bdfd19723 100644
--- a/src/client/qwaylandxdgshellv6integration_p.h
+++ b/src/client/qwaylandxdgshellv6integration_p.h
@@ -71,7 +71,7 @@ public:
 private:
     QWaylandXdgShellV6Integration(QWaylandDisplay *display);
 
-    QWaylandXdgShellV6 *m_xdgShell;
+    QWaylandXdgShellV6 *m_xdgShell = nullptr;
 };
 
 }
diff --git a/src/client/qwaylandxdgsurface.cpp b/src/client/qwaylandxdgsurface.cpp
index 60266af68..40ed9f07a 100644
--- a/src/client/qwaylandxdgsurface.cpp
+++ b/src/client/qwaylandxdgsurface.cpp
@@ -57,11 +57,6 @@ QWaylandXdgSurface::QWaylandXdgSurface(QWaylandXdgShell *shell, QWaylandWindow *
     , QtWayland::xdg_surface(shell->get_xdg_surface(window->object()))
     , m_window(window)
     , m_shell(shell)
-    , m_maximized(false)
-    , m_minimized(false)
-    , m_fullscreen(false)
-    , m_active(false)
-    , m_extendedWindow(nullptr)
 {
     if (window->display()->windowExtension())
         m_extendedWindow = new QWaylandExtendedSurface(window);
diff --git a/src/client/qwaylandxdgsurface_p.h b/src/client/qwaylandxdgsurface_p.h
index 00154ade0..fa7963206 100644
--- a/src/client/qwaylandxdgsurface_p.h
+++ b/src/client/qwaylandxdgsurface_p.h
@@ -112,13 +112,13 @@ private:
 private:
     QWaylandWindow *m_window;
     QWaylandXdgShell* m_shell;
-    bool m_maximized;
-    bool m_minimized;
-    bool m_fullscreen;
-    bool m_active;
+    bool m_maximized = false;
+    bool m_minimized = false;
+    bool m_fullscreen = false;
+    bool m_active = false;
     QSize m_normalSize;
     QMargins m_margins;
-    QWaylandExtendedSurface *m_extendedWindow;
+    QWaylandExtendedSurface *m_extendedWindow = nullptr;
 
     void xdg_surface_configure(int32_t width,
                                int32_t height,
diff --git a/src/compositor/compositor_api/qwaylandcompositor.cpp b/src/compositor/compositor_api/qwaylandcompositor.cpp
index 289af2f38..ae5ed1ec1 100644
--- a/src/compositor/compositor_api/qwaylandcompositor.cpp
+++ b/src/compositor/compositor_api/qwaylandcompositor.cpp
@@ -148,15 +148,6 @@ public:
 } // namespace
 
 QWaylandCompositorPrivate::QWaylandCompositorPrivate(QWaylandCompositor *compositor)
-    : display(nullptr)
-#if QT_CONFIG(opengl)
-    , use_hw_integration_extension(true)
-    , client_buffer_integration(nullptr)
-    , server_buffer_integration(nullptr)
-#endif
-    , retainSelection(false)
-    , preInitialized(false)
-    , initialized(false)
 {
     if (QGuiApplication::platformNativeInterface())
         display = static_cast<wl_display*>(QGuiApplication::platformNativeInterface()->nativeResourceForIntegration("server_wl_display"));
diff --git a/src/compositor/compositor_api/qwaylandcompositor_p.h b/src/compositor/compositor_api/qwaylandcompositor_p.h
index 18595a806..b1959e68f 100644
--- a/src/compositor/compositor_api/qwaylandcompositor_p.h
+++ b/src/compositor/compositor_api/qwaylandcompositor_p.h
@@ -128,7 +128,7 @@ protected:
     void loadServerBufferIntegration();
 
     QByteArray socket_name;
-    struct wl_display *display;
+    struct wl_display *display = nullptr;
 
     QList<QWaylandSeat *> seats;
     QList<QWaylandOutput *> outputs;
@@ -147,7 +147,7 @@ protected:
     QList<QWaylandClient *> clients;
 
 #if QT_CONFIG(opengl)
-    bool use_hw_integration_extension;
+    bool use_hw_integration_extension = true;
     QScopedPointer<QtWayland::HardwareIntegration> hw_integration;
     QScopedPointer<QtWayland::ClientBufferIntegration> client_buffer_integration;
     QScopedPointer<QtWayland::ServerBufferIntegration> server_buffer_integration;
@@ -155,9 +155,9 @@ protected:
 
     QScopedPointer<QWindowSystemEventHandler> eventHandler;
 
-    bool retainSelection;
-    bool preInitialized;
-    bool initialized;
+    bool retainSelection = false;
+    bool preInitialized = false;
+    bool initialized = false;
     QList<QPointer<QObject> > polish_objects;
 
     Q_DECLARE_PUBLIC(QWaylandCompositor)
diff --git a/src/compositor/compositor_api/qwaylandinputmethodcontrol.cpp b/src/compositor/compositor_api/qwaylandinputmethodcontrol.cpp
index 69e5971eb..a443502fa 100644
--- a/src/compositor/compositor_api/qwaylandinputmethodcontrol.cpp
+++ b/src/compositor/compositor_api/qwaylandinputmethodcontrol.cpp
@@ -150,11 +150,9 @@ void QWaylandInputMethodControl::defaultSeatChanged()
 }
 
 QWaylandInputMethodControlPrivate::QWaylandInputMethodControlPrivate(QWaylandSurface *surface)
-    : QObjectPrivate()
-    , compositor(surface->compositor())
+    : compositor(surface->compositor())
     , seat(compositor->defaultSeat())
     , surface(surface)
-    , enabled(false)
 {
 }
 
diff --git a/src/compositor/compositor_api/qwaylandinputmethodcontrol_p.h b/src/compositor/compositor_api/qwaylandinputmethodcontrol_p.h
index aedff6486..337cf0087 100644
--- a/src/compositor/compositor_api/qwaylandinputmethodcontrol_p.h
+++ b/src/compositor/compositor_api/qwaylandinputmethodcontrol_p.h
@@ -72,10 +72,10 @@ public:
 
     QWaylandTextInput *textInput() const;
 
-    QWaylandCompositor *compositor;
-    QWaylandSeat *seat;
-    QWaylandSurface *surface;
-    bool enabled;
+    QWaylandCompositor *compositor = nullptr;
+    QWaylandSeat *seat = nullptr;
+    QWaylandSurface *surface = nullptr;
+    bool enabled = false;
 };
 
 QT_END_NAMESPACE
diff --git a/src/compositor/compositor_api/qwaylandkeyboard.cpp b/src/compositor/compositor_api/qwaylandkeyboard.cpp
index e35c0f371..7ab8bff9e 100644
--- a/src/compositor/compositor_api/qwaylandkeyboard.cpp
+++ b/src/compositor/compositor_api/qwaylandkeyboard.cpp
@@ -59,22 +59,7 @@
 QT_BEGIN_NAMESPACE
 
 QWaylandKeyboardPrivate::QWaylandKeyboardPrivate(QWaylandSeat *seat)
-    : QtWaylandServer::wl_keyboard()
-    , seat(seat)
-    , focus()
-    , focusResource()
-    , keys()
-    , modsDepressed()
-    , modsLatched()
-    , modsLocked()
-    , group()
-    , pendingKeymap(false)
-#if QT_CONFIG(xkbcommon_evdev)
-    , keymap_fd(-1)
-    , xkb_state(nullptr)
-#endif
-    , repeatRate(40)
-    , repeatDelay(400)
+    : seat(seat)
 {
 }
 
diff --git a/src/compositor/compositor_api/qwaylandkeyboard_p.h b/src/compositor/compositor_api/qwaylandkeyboard_p.h
index 0b47f8e8e..bcc4abb1a 100644
--- a/src/compositor/compositor_api/qwaylandkeyboard_p.h
+++ b/src/compositor/compositor_api/qwaylandkeyboard_p.h
@@ -114,29 +114,29 @@ private:
 
     void sendRepeatInfo();
 
-    QWaylandSeat *seat;
+    QWaylandSeat *seat = nullptr;
 
-    QWaylandSurface *focus;
-    Resource *focusResource;
+    QWaylandSurface *focus = nullptr;
+    Resource *focusResource = nullptr;
     QWaylandDestroyListener focusDestroyListener;
 
     QVector<uint32_t> keys;
-    uint32_t modsDepressed;
-    uint32_t modsLatched;
-    uint32_t modsLocked;
-    uint32_t group;
+    uint32_t modsDepressed = 0;
+    uint32_t modsLatched = 0;
+    uint32_t modsLocked = 0;
+    uint32_t group = 0;
 
-    bool pendingKeymap;
+    bool pendingKeymap = false;
 #if QT_CONFIG(xkbcommon_evdev)
     size_t keymap_size;
-    int keymap_fd;
-    char *keymap_area;
-    struct xkb_context *xkb_context;
-    struct xkb_state *xkb_state;
+    int keymap_fd = -1;
+    char *keymap_area = nullptr;
+    struct xkb_context *xkb_context = nullptr;
+    struct xkb_state *xkb_state = nullptr;
 #endif
 
-    quint32 repeatRate;
-    quint32 repeatDelay;
+    quint32 repeatRate = 40;
+    quint32 repeatDelay = 400;
 };
 
 QT_END_NAMESPACE
diff --git a/src/compositor/compositor_api/qwaylandoutput.cpp b/src/compositor/compositor_api/qwaylandoutput.cpp
index 7627195da..f7782da9c 100644
--- a/src/compositor/compositor_api/qwaylandoutput.cpp
+++ b/src/compositor/compositor_api/qwaylandoutput.cpp
@@ -104,16 +104,6 @@ static QtWaylandServer::wl_output::transform toWlTransform(const QWaylandOutput:
 }
 
 QWaylandOutputPrivate::QWaylandOutputPrivate()
-    : QtWaylandServer::wl_output()
-    , compositor(nullptr)
-    , window(nullptr)
-    , currentMode(-1)
-    , preferredMode(-1)
-    , subpixel(QWaylandOutput::SubpixelUnknown)
-    , transform(QWaylandOutput::TransformNormal)
-    , scaleFactor(1)
-    , sizeFollowsWindow(false)
-    , initialized(false)
 {
 }
 
diff --git a/src/compositor/compositor_api/qwaylandoutput_p.h b/src/compositor/compositor_api/qwaylandoutput_p.h
index 5a21c3de7..28a19ff89 100644
--- a/src/compositor/compositor_api/qwaylandoutput_p.h
+++ b/src/compositor/compositor_api/qwaylandoutput_p.h
@@ -70,15 +70,11 @@ QT_BEGIN_NAMESPACE
 struct QWaylandSurfaceViewMapper
 {
     QWaylandSurfaceViewMapper()
-        : surface(nullptr)
-        , views()
-        , has_entered(false)
     {}
 
     QWaylandSurfaceViewMapper(QWaylandSurface *s, QWaylandView *v)
         : surface(s)
         , views(1, v)
-        , has_entered(false)
     {}
 
     QWaylandView *maybePrimaryView() const
@@ -90,9 +86,9 @@ struct QWaylandSurfaceViewMapper
         return nullptr;
     }
 
-    QWaylandSurface *surface;
+    QWaylandSurface *surface = nullptr;
     QVector<QWaylandView *> views;
-    bool has_entered;
+    bool has_entered = false;
 };
 
 class Q_WAYLAND_COMPOSITOR_EXPORT QWaylandOutputPrivate : public QObjectPrivate, public QtWaylandServer::wl_output
@@ -116,22 +112,22 @@ protected:
     void output_bind_resource(Resource *resource) override;
 
 private:
-    QWaylandCompositor *compositor;
-    QWindow *window;
+    QWaylandCompositor *compositor = nullptr;
+    QWindow *window = nullptr;
     QString manufacturer;
     QString model;
     QPoint position;
     QVector<QWaylandOutputMode> modes;
-    int currentMode;
-    int preferredMode;
+    int currentMode = -1;
+    int preferredMode = -1;
     QRect availableGeometry;
     QVector<QWaylandSurfaceViewMapper> surfaceViews;
     QSize physicalSize;
-    QWaylandOutput::Subpixel subpixel;
-    QWaylandOutput::Transform transform;
-    int scaleFactor;
-    bool sizeFollowsWindow;
-    bool initialized;
+    QWaylandOutput::Subpixel subpixel = QWaylandOutput::SubpixelUnknown;
+    QWaylandOutput::Transform transform = QWaylandOutput::TransformNormal;
+    int scaleFactor = 1;
+    bool sizeFollowsWindow = false;
+    bool initialized = false;
 
     Q_DECLARE_PUBLIC(QWaylandOutput)
     Q_DISABLE_COPY(QWaylandOutputPrivate)
diff --git a/src/compositor/compositor_api/qwaylandpointer.cpp b/src/compositor/compositor_api/qwaylandpointer.cpp
index 4bdee9be2..77e736a58 100644
--- a/src/compositor/compositor_api/qwaylandpointer.cpp
+++ b/src/compositor/compositor_api/qwaylandpointer.cpp
@@ -47,12 +47,7 @@ QT_BEGIN_NAMESPACE
 QWaylandSurfaceRole QWaylandPointerPrivate::s_role("wl_pointer");
 
 QWaylandPointerPrivate::QWaylandPointerPrivate(QWaylandPointer *pointer, QWaylandSeat *seat)
-    : QObjectPrivate()
-    , wl_pointer()
-    , seat(seat)
-    , output()
-    , enterSerial(0)
-    , buttonCount()
+    : seat(seat)
 {
     Q_UNUSED(pointer);
 }
diff --git a/src/compositor/compositor_api/qwaylandpointer_p.h b/src/compositor/compositor_api/qwaylandpointer_p.h
index 11076f34b..94f44f604 100644
--- a/src/compositor/compositor_api/qwaylandpointer_p.h
+++ b/src/compositor/compositor_api/qwaylandpointer_p.h
@@ -92,17 +92,17 @@ private:
     void sendLeave();
     void ensureEntered(QWaylandSurface *surface);
 
-    QWaylandSeat *seat;
-    QWaylandOutput *output;
+    QWaylandSeat *seat = nullptr;
+    QWaylandOutput *output = nullptr;
     QPointer<QWaylandSurface> enteredSurface;
 
     QPointF localPosition;
     QPointF spacePosition;
 
-    bool hasSentEnter;
-    uint enterSerial;
+    bool hasSentEnter = false;
+    uint enterSerial = 0;
 
-    int buttonCount;
+    int buttonCount = 0;
 
     QWaylandDestroyListener enteredSurfaceDestroyListener;
 
diff --git a/src/compositor/compositor_api/qwaylandquickitem.cpp b/src/compositor/compositor_api/qwaylandquickitem.cpp
index 91e85b884..23b52e0b4 100644
--- a/src/compositor/compositor_api/qwaylandquickitem.cpp
+++ b/src/compositor/compositor_api/qwaylandquickitem.cpp
@@ -140,8 +140,7 @@ static const struct {
 };
 
 QWaylandBufferMaterialShader::QWaylandBufferMaterialShader(QWaylandBufferRef::BufferFormatEgl format)
-    : QSGMaterialShader()
-    , m_format(format)
+    : m_format(format)
 {
     setShaderSourceFile(QOpenGLShader::Vertex, QString::fromLatin1(bufferTypes[format].vertexShaderSourceFile));
     setShaderSourceFile(QOpenGLShader::Fragment, QString::fromLatin1(bufferTypes[format].fragmentShaderSourceFile));
@@ -183,8 +182,7 @@ void QWaylandBufferMaterialShader::initialize()
 }
 
 QWaylandBufferMaterial::QWaylandBufferMaterial(QWaylandBufferRef::BufferFormatEgl format)
-    : QSGMaterial()
-    , m_format(format)
+    : m_format(format)
 {
     QOpenGLFunctions *gl = QOpenGLContext::currentContext()->functions();
 
@@ -267,8 +265,6 @@ class QWaylandSurfaceTextureProvider : public QSGTextureProvider
 {
 public:
     QWaylandSurfaceTextureProvider()
-        : m_smooth(false)
-        , m_sgTex(nullptr)
     {
     }
 
@@ -313,8 +309,8 @@ public:
 
     void setSmooth(bool smooth) { m_smooth = smooth; }
 private:
-    bool m_smooth;
-    QSGTexture *m_sgTex;
+    bool m_smooth = false;
+    QSGTexture *m_sgTex = nullptr;
     QWaylandBufferRef m_ref;
 };
 
diff --git a/src/compositor/compositor_api/qwaylandquickitem_p.h b/src/compositor/compositor_api/qwaylandquickitem_p.h
index 400cda742..de405a943 100644
--- a/src/compositor/compositor_api/qwaylandquickitem_p.h
+++ b/src/compositor/compositor_api/qwaylandquickitem_p.h
@@ -107,22 +107,7 @@ class QWaylandQuickItemPrivate : public QQuickItemPrivate
 {
     Q_DECLARE_PUBLIC(QWaylandQuickItem)
 public:
-    QWaylandQuickItemPrivate()
-        : QQuickItemPrivate()
-        , view(nullptr)
-        , oldSurface(nullptr)
-        , provider(nullptr)
-        , paintEnabled(true)
-        , touchEventsEnabled(true)
-        , inputEventsEnabled(true)
-        , isDragging(false)
-        , newTexture(false)
-        , focusOnClick(true)
-        , sizeFollowsSurface(true)
-        , connectedWindow(nullptr)
-        , origin(QWaylandSurface::OriginTopLeft)
-    {
-    }
+    QWaylandQuickItemPrivate() = default;
 
     void init()
     {
@@ -169,20 +154,20 @@ public:
     static QMutex *mutex;
 
     QScopedPointer<QWaylandView> view;
-    QWaylandSurface *oldSurface;
-    mutable QWaylandSurfaceTextureProvider *provider;
-    bool paintEnabled;
-    bool touchEventsEnabled;
-    bool inputEventsEnabled;
-    bool isDragging;
-    bool newTexture;
-    bool focusOnClick;
-    bool sizeFollowsSurface;
+    QWaylandSurface *oldSurface = nullptr;
+    mutable QWaylandSurfaceTextureProvider *provider = nullptr;
+    bool paintEnabled = true;
+    bool touchEventsEnabled = true;
+    bool inputEventsEnabled = true;
+    bool isDragging = false;
+    bool newTexture = false;
+    bool focusOnClick = true;
+    bool sizeFollowsSurface = true;
     QPoint hoverPos;
     QMatrix4x4 lastMatrix;
 
-    QQuickWindow *connectedWindow;
-    QWaylandSurface::Origin origin;
+    QQuickWindow *connectedWindow = nullptr;
+    QWaylandSurface::Origin origin = QWaylandSurface::OriginTopLeft;
     QPointer<QObject> subsurfaceHandler;
     QVector<QWaylandSeat *> touchingSeats;
 };
diff --git a/src/compositor/compositor_api/qwaylandquickoutput.cpp b/src/compositor/compositor_api/qwaylandquickoutput.cpp
index db7cc50bb..79e4fdec7 100644
--- a/src/compositor/compositor_api/qwaylandquickoutput.cpp
+++ b/src/compositor/compositor_api/qwaylandquickoutput.cpp
@@ -45,16 +45,11 @@
 QT_BEGIN_NAMESPACE
 
 QWaylandQuickOutput::QWaylandQuickOutput()
-    : QWaylandOutput()
-    , m_updateScheduled(false)
-    , m_automaticFrameCallback(true)
 {
 }
 
 QWaylandQuickOutput::QWaylandQuickOutput(QWaylandCompositor *compositor, QWindow *window)
     : QWaylandOutput(compositor, window)
-    , m_updateScheduled(false)
-    , m_automaticFrameCallback(true)
 {
 }
 
diff --git a/src/compositor/compositor_api/qwaylandquickoutput.h b/src/compositor/compositor_api/qwaylandquickoutput.h
index f023872c0..cd79f14f5 100644
--- a/src/compositor/compositor_api/qwaylandquickoutput.h
+++ b/src/compositor/compositor_api/qwaylandquickoutput.h
@@ -79,8 +79,8 @@ protected:
 private:
     void doFrameCallbacks();
 
-    bool m_updateScheduled;
-    bool m_automaticFrameCallback;
+    bool m_updateScheduled = false;
+    bool m_automaticFrameCallback = true;
 };
 
 QT_END_NAMESPACE
diff --git a/src/compositor/compositor_api/qwaylandquicksurface.cpp b/src/compositor/compositor_api/qwaylandquicksurface.cpp
index 1197e9e43..a1269b117 100644
--- a/src/compositor/compositor_api/qwaylandquicksurface.cpp
+++ b/src/compositor/compositor_api/qwaylandquicksurface.cpp
@@ -56,9 +56,6 @@ class QWaylandQuickSurfacePrivate : public QWaylandSurfacePrivate
     Q_DECLARE_PUBLIC(QWaylandQuickSurface)
 public:
     QWaylandQuickSurfacePrivate()
-        : QWaylandSurfacePrivate()
-        , useTextureAlpha(true)
-        , clientRenderingEnabled(true)
     {
     }
 
@@ -66,8 +63,8 @@ public:
     {
     }
 
-    bool useTextureAlpha;
-    bool clientRenderingEnabled;
+    bool useTextureAlpha = true;
+    bool clientRenderingEnabled = true;
 };
 
 QWaylandQuickSurface::QWaylandQuickSurface()
diff --git a/src/compositor/compositor_api/qwaylandresource.cpp b/src/compositor/compositor_api/qwaylandresource.cpp
index 7cfcce132..f3d010830 100644
--- a/src/compositor/compositor_api/qwaylandresource.cpp
+++ b/src/compositor/compositor_api/qwaylandresource.cpp
@@ -42,7 +42,6 @@
 QT_BEGIN_NAMESPACE
 
 QWaylandResource::QWaylandResource()
-                : m_resource(nullptr)
 {
 }
 
diff --git a/src/compositor/compositor_api/qwaylandresource.h b/src/compositor/compositor_api/qwaylandresource.h
index f8c50c082..11ab64da9 100644
--- a/src/compositor/compositor_api/qwaylandresource.h
+++ b/src/compositor/compositor_api/qwaylandresource.h
@@ -57,7 +57,7 @@ public:
     wl_resource *resource() const { return m_resource; }
 
 private:
-    wl_resource *m_resource;
+    wl_resource *m_resource = nullptr;
 };
 
 QT_END_NAMESPACE
diff --git a/src/compositor/compositor_api/qwaylandseat.cpp b/src/compositor/compositor_api/qwaylandseat.cpp
index 2ee32bfb2..c67e6020d 100644
--- a/src/compositor/compositor_api/qwaylandseat.cpp
+++ b/src/compositor/compositor_api/qwaylandseat.cpp
@@ -60,21 +60,11 @@
 
 QT_BEGIN_NAMESPACE
 
-QWaylandSeatPrivate::QWaylandSeatPrivate(QWaylandSeat *seat)
-    : QObjectPrivate()
-    , QtWaylandServer::wl_seat()
-    , isInitialized(false)
-    , compositor(nullptr)
-    , mouseFocus(nullptr)
-    , keyboardFocus(nullptr)
-    , capabilities()
+QWaylandSeatPrivate::QWaylandSeatPrivate(QWaylandSeat *seat) :
 #if QT_CONFIG(wayland_datadevice)
-    , data_device()
+    drag_handle(new QWaylandDrag(seat)),
 #endif
-#if QT_CONFIG(draganddrop)
-    , drag_handle(new QWaylandDrag(seat))
-#endif
-    , keymap(new QWaylandKeymap())
+    keymap(new QWaylandKeymap())
 {
 }
 
diff --git a/src/compositor/compositor_api/qwaylandseat_p.h b/src/compositor/compositor_api/qwaylandseat_p.h
index 28a5fd4f0..1e182f41a 100644
--- a/src/compositor/compositor_api/qwaylandseat_p.h
+++ b/src/compositor/compositor_api/qwaylandseat_p.h
@@ -114,10 +114,10 @@ protected:
     void seat_destroy_resource(wl_seat::Resource *resource) override;
 
 private:
-    bool isInitialized;
-    QWaylandCompositor *compositor;
-    QWaylandView *mouseFocus;
-    QWaylandSurface *keyboardFocus;
+    bool isInitialized = false;
+    QWaylandCompositor *compositor = nullptr;
+    QWaylandView *mouseFocus = nullptr;
+    QWaylandSurface *keyboardFocus = nullptr;
     QWaylandSeat::CapabilityFlags capabilities;
 
     QScopedPointer<QWaylandPointer> pointer;
diff --git a/src/compositor/compositor_api/qwaylandsurface.cpp b/src/compositor/compositor_api/qwaylandsurface.cpp
index a5316f535..ed9bef3cf 100644
--- a/src/compositor/compositor_api/qwaylandsurface.cpp
+++ b/src/compositor/compositor_api/qwaylandsurface.cpp
@@ -75,7 +75,6 @@ public:
     FrameCallback(QWaylandSurface *surf, wl_resource *res)
         : surface(surf)
         , resource(res)
-        , canSend(false)
     {
 #if WAYLAND_VERSION_MAJOR < 1 || (WAYLAND_VERSION_MAJOR == 1 && WAYLAND_VERSION_MINOR <= 2)
         res->data = this;
@@ -112,7 +111,7 @@ public:
     }
     QWaylandSurface *surface;
     wl_resource *resource;
-    bool canSend;
+    bool canSend = false;
 };
 }
 static QRegion infiniteRegion() {
@@ -125,22 +124,7 @@ QList<QWaylandSurfacePrivate *> QWaylandSurfacePrivate::uninitializedSurfaces;
 #endif
 
 QWaylandSurfacePrivate::QWaylandSurfacePrivate()
-    : QtWaylandServer::wl_surface()
-    , compositor(nullptr)
-    , refCount(1)
-    , client(nullptr)
-    , role(nullptr)
-    , inputRegion(infiniteRegion())
-    , bufferScale(1)
-    , isCursorSurface(false)
-    , destroyed(false)
-    , hasContent(false)
-    , isInitialized(false)
-    , contentOrientation(Qt::PrimaryOrientation)
-#if QT_CONFIG(im)
-    , inputMethodControl(nullptr)
-#endif
-    , subsurface(nullptr)
+    : inputRegion(infiniteRegion())
 {
     pending.buffer = QWaylandBufferRef();
     pending.newlyAttached = false;
diff --git a/src/compositor/compositor_api/qwaylandsurface_p.h b/src/compositor/compositor_api/qwaylandsurface_p.h
index 3c43fc043..3dc9bf20e 100644
--- a/src/compositor/compositor_api/qwaylandsurface_p.h
+++ b/src/compositor/compositor_api/qwaylandsurface_p.h
@@ -140,13 +140,13 @@ protected:
     QtWayland::ClientBuffer *getBuffer(struct ::wl_resource *buffer);
 
 public: //member variables
-    QWaylandCompositor *compositor;
-    int refCount;
-    QWaylandClient *client;
+    QWaylandCompositor *compositor = nullptr;
+    int refCount = 1;
+    QWaylandClient *client = nullptr;
     QList<QWaylandView *> views;
     QRegion damage;
     QWaylandBufferRef bufferRef;
-    QWaylandSurfaceRole *role;
+    QWaylandSurfaceRole *role = nullptr;
 
     struct {
         QWaylandBufferRef buffer;
@@ -167,15 +167,15 @@ public: //member variables
     QRegion opaqueRegion;
 
     QSize size;
-    int bufferScale;
-    bool isCursorSurface;
-    bool destroyed;
-    bool hasContent;
-    bool isInitialized;
-    Qt::ScreenOrientation contentOrientation;
+    int bufferScale = 1;
+    bool isCursorSurface = false;
+    bool destroyed = false;
+    bool hasContent = false;
+    bool isInitialized = false;
+    Qt::ScreenOrientation contentOrientation = Qt::PrimaryOrientation;
     QWindow::Visibility visibility;
 #if QT_CONFIG(im)
-    QWaylandInputMethodControl *inputMethodControl;
+    QWaylandInputMethodControl *inputMethodControl = nullptr;
 #endif
 
     class Subsurface : public QtWaylandServer::wl_subsurface
@@ -198,7 +198,7 @@ public: //member variables
         QPoint position;
     };
 
-    Subsurface *subsurface;
+    Subsurface *subsurface = nullptr;
 
 #ifndef QT_NO_DEBUG
     static QList<QWaylandSurfacePrivate *> uninitializedSurfaces;
diff --git a/src/compositor/compositor_api/qwaylandtouch.cpp b/src/compositor/compositor_api/qwaylandtouch.cpp
index 396a3b689..3e7298001 100644
--- a/src/compositor/compositor_api/qwaylandtouch.cpp
+++ b/src/compositor/compositor_api/qwaylandtouch.cpp
@@ -50,8 +50,7 @@
 QT_BEGIN_NAMESPACE
 
 QWaylandTouchPrivate::QWaylandTouchPrivate(QWaylandTouch *touch, QWaylandSeat *seat)
-    : wl_touch()
-    , seat(seat)
+    : seat(seat)
 {
     Q_UNUSED(touch);
 }
diff --git a/src/compositor/compositor_api/qwaylandview_p.h b/src/compositor/compositor_api/qwaylandview_p.h
index 1cc55954c..b9cb0d07b 100644
--- a/src/compositor/compositor_api/qwaylandview_p.h
+++ b/src/compositor/compositor_api/qwaylandview_p.h
@@ -71,32 +71,24 @@ public:
     static QWaylandViewPrivate *get(QWaylandView *view) { return view->d_func(); }
 
     QWaylandViewPrivate()
-        : renderObject(nullptr)
-        , surface(nullptr)
-        , output(nullptr)
-        , nextBufferCommitted(false)
-        , bufferLocked(false)
-        , broadcastRequestedPositionChanged(false)
-        , forceAdvanceSucceed(false)
-        , allowDiscardFrontBuffer(false)
     { }
 
     void markSurfaceAsDestroyed(QWaylandSurface *surface);
 
-    QObject *renderObject;
-    QWaylandSurface *surface;
-    QWaylandOutput *output;
+    QObject *renderObject = nullptr;
+    QWaylandSurface *surface = nullptr;
+    QWaylandOutput *output = nullptr;
     QPointF requestedPos;
     QMutex bufferMutex;
     QWaylandBufferRef currentBuffer;
     QRegion currentDamage;
     QWaylandBufferRef nextBuffer;
     QRegion nextDamage;
-    bool nextBufferCommitted;
-    bool bufferLocked;
-    bool broadcastRequestedPositionChanged;
-    bool forceAdvanceSucceed;
-    bool allowDiscardFrontBuffer;
+    bool nextBufferCommitted = false;
+    bool bufferLocked = false;
+    bool broadcastRequestedPositionChanged = false;
+    bool forceAdvanceSucceed = false;
+    bool allowDiscardFrontBuffer = false;
     bool independentFrameCallback = false; //If frame callbacks are independent of the main quick scene graph
 };
 
diff --git a/src/compositor/extensions/qwaylandiviapplication.cpp b/src/compositor/extensions/qwaylandiviapplication.cpp
index 8295d2a18..57b1627b5 100644
--- a/src/compositor/extensions/qwaylandiviapplication.cpp
+++ b/src/compositor/extensions/qwaylandiviapplication.cpp
@@ -168,8 +168,6 @@ QByteArray QWaylandIviApplication::interfaceName()
  */
 
 QWaylandIviApplicationPrivate::QWaylandIviApplicationPrivate()
-    : QWaylandCompositorExtensionPrivate()
-    , ivi_application()
 {
 }
 
diff --git a/src/compositor/extensions/qwaylandivisurface.cpp b/src/compositor/extensions/qwaylandivisurface.cpp
index 2bdd4a14d..716cc868f 100644
--- a/src/compositor/extensions/qwaylandivisurface.cpp
+++ b/src/compositor/extensions/qwaylandivisurface.cpp
@@ -218,11 +218,6 @@ void QWaylandIviSurface::initialize()
 }
 
 QWaylandIviSurfacePrivate::QWaylandIviSurfacePrivate()
-    : QWaylandCompositorExtensionPrivate()
-    , ivi_surface()
-    , m_iviApplication(nullptr)
-    , m_surface(nullptr)
-    , m_iviId(UINT_MAX)
 {
 }
 
diff --git a/src/compositor/extensions/qwaylandivisurface_p.h b/src/compositor/extensions/qwaylandivisurface_p.h
index 3edd0b1e8..0ead0647b 100644
--- a/src/compositor/extensions/qwaylandivisurface_p.h
+++ b/src/compositor/extensions/qwaylandivisurface_p.h
@@ -75,9 +75,9 @@ protected:
     void ivi_surface_destroy(Resource *resource) override;
 
 private:
-    QWaylandIviApplication *m_iviApplication;
-    QWaylandSurface *m_surface;
-    uint m_iviId;
+    QWaylandIviApplication *m_iviApplication = nullptr;
+    QWaylandSurface *m_surface = nullptr;
+    uint m_iviId = UINT_MAX;
 
     static QWaylandSurfaceRole s_role;
 };
diff --git a/src/compositor/extensions/qwaylandqtwindowmanager.cpp b/src/compositor/extensions/qwaylandqtwindowmanager.cpp
index 4943681c6..86678b2e6 100644
--- a/src/compositor/extensions/qwaylandqtwindowmanager.cpp
+++ b/src/compositor/extensions/qwaylandqtwindowmanager.cpp
@@ -50,9 +50,6 @@
 QT_BEGIN_NAMESPACE
 
 QWaylandQtWindowManagerPrivate::QWaylandQtWindowManagerPrivate()
-    : QWaylandCompositorExtensionPrivate()
-    , qt_windowmanager()
-    , showIsFullScreen(false)
 {
 }
 
diff --git a/src/compositor/extensions/qwaylandqtwindowmanager_p.h b/src/compositor/extensions/qwaylandqtwindowmanager_p.h
index 0856b3971..91e8e26cd 100644
--- a/src/compositor/extensions/qwaylandqtwindowmanager_p.h
+++ b/src/compositor/extensions/qwaylandqtwindowmanager_p.h
@@ -74,7 +74,7 @@ protected:
     void windowmanager_open_url(Resource *resource, uint32_t remaining, const QString &url) override;
 
 private:
-    bool showIsFullScreen;
+    bool showIsFullScreen = false;
     QMap<Resource*, QString> urls;
 };
 
diff --git a/src/compositor/extensions/qwaylandquickshellsurfaceitem.cpp b/src/compositor/extensions/qwaylandquickshellsurfaceitem.cpp
index 2b603099b..6b8845797 100644
--- a/src/compositor/extensions/qwaylandquickshellsurfaceitem.cpp
+++ b/src/compositor/extensions/qwaylandquickshellsurfaceitem.cpp
@@ -213,7 +213,7 @@ void QWaylandQuickShellEventFilter::stopFilter()
 QWaylandQuickShellEventFilter *QWaylandQuickShellEventFilter::self = nullptr;
 
 QWaylandQuickShellEventFilter::QWaylandQuickShellEventFilter(QObject *parent)
-    : QObject(parent), eventFilterInstalled(false), waitForRelease(false), closePopups(nullptr)
+    : QObject(parent)
 {
 }
 
diff --git a/src/compositor/extensions/qwaylandquickshellsurfaceitem_p.h b/src/compositor/extensions/qwaylandquickshellsurfaceitem_p.h
index 9549cb0e3..abb56221e 100644
--- a/src/compositor/extensions/qwaylandquickshellsurfaceitem_p.h
+++ b/src/compositor/extensions/qwaylandquickshellsurfaceitem_p.h
@@ -65,14 +65,10 @@ class Q_WAYLAND_COMPOSITOR_EXPORT QWaylandQuickShellSurfaceItemPrivate : public
 {
 public:
     QWaylandQuickShellSurfaceItemPrivate()
-        : QWaylandQuickItemPrivate()
-        , m_shellIntegration(nullptr)
-        , m_shellSurface(nullptr)
-        , m_moveItem(nullptr)
     {}
-    QWaylandQuickShellIntegration *m_shellIntegration;
-    QWaylandShellSurface *m_shellSurface;
-    QQuickItem *m_moveItem;
+    QWaylandQuickShellIntegration *m_shellIntegration = nullptr;
+    QWaylandShellSurface *m_shellSurface = nullptr;
+    QQuickItem *m_moveItem = nullptr;
 };
 
 class Q_WAYLAND_COMPOSITOR_EXPORT QWaylandQuickShellIntegration : public QObject
@@ -100,10 +96,10 @@ private:
 
     QWaylandQuickShellEventFilter(QObject *parent = nullptr);
     bool eventFilter(QObject *, QEvent *) override;
-    bool eventFilterInstalled;
-    bool waitForRelease;
+    bool eventFilterInstalled = false;
+    bool waitForRelease = false;
     QPointer<QWaylandClient> client;
-    CallbackFunction closePopups;
+    CallbackFunction closePopups = nullptr;
     QBasicTimer mousePressTimeout;
     static QWaylandQuickShellEventFilter *self;
 };
diff --git a/src/compositor/extensions/qwaylandshell.cpp b/src/compositor/extensions/qwaylandshell.cpp
index adb5827d4..12479186b 100644
--- a/src/compositor/extensions/qwaylandshell.cpp
+++ b/src/compositor/extensions/qwaylandshell.cpp
@@ -43,12 +43,10 @@
 QT_BEGIN_NAMESPACE
 
 QWaylandShellPrivate::QWaylandShellPrivate()
-    : focusPolicy(QWaylandShell::AutomaticFocus)
 {
 }
 
 QWaylandShell::QWaylandShell()
-    : QWaylandCompositorExtension()
 {
 }
 
diff --git a/src/compositor/extensions/qwaylandshell_p.h b/src/compositor/extensions/qwaylandshell_p.h
index 968bf5bd7..f333b9b4c 100644
--- a/src/compositor/extensions/qwaylandshell_p.h
+++ b/src/compositor/extensions/qwaylandshell_p.h
@@ -62,7 +62,7 @@ class Q_WAYLAND_COMPOSITOR_EXPORT QWaylandShellPrivate : public QWaylandComposit
 public:
     QWaylandShellPrivate();
 
-    QWaylandShell::FocusPolicy focusPolicy;
+    QWaylandShell::FocusPolicy focusPolicy = QWaylandShell::AutomaticFocus;
 };
 
 QT_END_NAMESPACE
diff --git a/src/compositor/extensions/qwaylandtextinput.cpp b/src/compositor/extensions/qwaylandtextinput.cpp
index 552aa0667..b832bb737 100644
--- a/src/compositor/extensions/qwaylandtextinput.cpp
+++ b/src/compositor/extensions/qwaylandtextinput.cpp
@@ -54,13 +54,6 @@
 QT_BEGIN_NAMESPACE
 
 QWaylandTextInputClientState::QWaylandTextInputClientState()
-    : hints(Qt::ImhNone)
-    , cursorRectangle()
-    , surroundingText()
-    , cursorPosition(0)
-    , anchorPosition(0)
-    , preferredLanguage()
-    , changedState()
 {
 }
 
@@ -121,17 +114,9 @@ Qt::InputMethodQueries QWaylandTextInputClientState::mergeChanged(const QWayland
 }
 
 QWaylandTextInputPrivate::QWaylandTextInputPrivate(QWaylandCompositor *compositor)
-    : QWaylandCompositorExtensionPrivate()
-    , QtWaylandServer::zwp_text_input_v2()
-    , compositor(compositor)
-    , focus(nullptr)
-    , focusResource(nullptr)
-    , focusDestroyListener()
-    , inputPanelVisible(false)
+    : compositor(compositor)
     , currentState(new QWaylandTextInputClientState)
     , pendingState(new QWaylandTextInputClientState)
-    , serial(0)
-    , enabledSurfaces()
 {
 }
 
diff --git a/src/compositor/extensions/qwaylandtextinput_p.h b/src/compositor/extensions/qwaylandtextinput_p.h
index e96b0c01e..976c96198 100644
--- a/src/compositor/extensions/qwaylandtextinput_p.h
+++ b/src/compositor/extensions/qwaylandtextinput_p.h
@@ -76,11 +76,11 @@ public:
     Qt::InputMethodQueries updatedQueries(const QWaylandTextInputClientState &other) const;
     Qt::InputMethodQueries mergeChanged(const QWaylandTextInputClientState &other);
 
-    Qt::InputMethodHints hints;
+    Qt::InputMethodHints hints = Qt::ImhNone;
     QRect cursorRectangle;
     QString surroundingText;
-    int cursorPosition;
-    int anchorPosition;
+    int cursorPosition = 0;
+    int anchorPosition = 0;
     QString preferredLanguage;
 
     Qt::InputMethodQueries changedState;
@@ -102,18 +102,18 @@ public:
 
     void setFocus(QWaylandSurface *surface);
 
-    QWaylandCompositor *compositor;
+    QWaylandCompositor *compositor = nullptr;
 
-    QWaylandSurface *focus;
-    Resource *focusResource;
+    QWaylandSurface *focus = nullptr;
+    Resource *focusResource = nullptr;
     QWaylandDestroyListener focusDestroyListener;
 
-    bool inputPanelVisible;
+    bool inputPanelVisible = false;
 
     QScopedPointer<QWaylandTextInputClientState> currentState;
     QScopedPointer<QWaylandTextInputClientState> pendingState;
 
-    uint32_t serial;
+    uint32_t serial = 0;
 
     QHash<Resource *, QWaylandSurface*> enabledSurfaces;
 
diff --git a/src/compositor/extensions/qwaylandtextinputmanager.cpp b/src/compositor/extensions/qwaylandtextinputmanager.cpp
index 0fda80990..f18ca5d51 100644
--- a/src/compositor/extensions/qwaylandtextinputmanager.cpp
+++ b/src/compositor/extensions/qwaylandtextinputmanager.cpp
@@ -48,8 +48,6 @@
 QT_BEGIN_NAMESPACE
 
 QWaylandTextInputManagerPrivate::QWaylandTextInputManagerPrivate()
-    : QWaylandCompositorExtensionPrivate()
-    , QtWaylandServer::zwp_text_input_manager_v2()
 {
 }
 
diff --git a/src/compositor/extensions/qwaylandwlshell.cpp b/src/compositor/extensions/qwaylandwlshell.cpp
index 59b311919..c3d15c6aa 100644
--- a/src/compositor/extensions/qwaylandwlshell.cpp
+++ b/src/compositor/extensions/qwaylandwlshell.cpp
@@ -58,8 +58,6 @@ QT_BEGIN_NAMESPACE
 QWaylandSurfaceRole QWaylandWlShellSurfacePrivate::s_role("wl_shell_surface");
 
 QWaylandWlShellPrivate::QWaylandWlShellPrivate()
-    : QWaylandCompositorExtensionPrivate()
-    , wl_shell()
 {
 }
 
@@ -102,11 +100,6 @@ void QWaylandWlShellPrivate::unregisterShellSurface(QWaylandWlShellSurface *shel
 }
 
 QWaylandWlShellSurfacePrivate::QWaylandWlShellSurfacePrivate()
-    : QWaylandCompositorExtensionPrivate()
-    , wl_shell_surface()
-    , m_shell(nullptr)
-    , m_surface(nullptr)
-    , m_windowType(Qt::WindowType::Window)
 {
 }
 
diff --git a/src/compositor/extensions/qwaylandwlshell_p.h b/src/compositor/extensions/qwaylandwlshell_p.h
index 994b4dcbf..4e91eabc9 100644
--- a/src/compositor/extensions/qwaylandwlshell_p.h
+++ b/src/compositor/extensions/qwaylandwlshell_p.h
@@ -100,14 +100,14 @@ public:
     void setWindowType(Qt::WindowType windowType);
 
 private:
-    QWaylandWlShell *m_shell;
+    QWaylandWlShell *m_shell = nullptr;
     QPointer<QWaylandSurface> m_surface;
 
     QSet<uint32_t> m_pings;
 
     QString m_title;
     QString m_className;
-    Qt::WindowType m_windowType;
+    Qt::WindowType m_windowType = Qt::WindowType::Window;
 
     void shell_surface_destroy_resource(Resource *resource) override;
 
diff --git a/src/compositor/extensions/qwaylandwlshellintegration.cpp b/src/compositor/extensions/qwaylandwlshellintegration.cpp
index 7e3d31f18..9e1e9dd6d 100644
--- a/src/compositor/extensions/qwaylandwlshellintegration.cpp
+++ b/src/compositor/extensions/qwaylandwlshellintegration.cpp
@@ -52,10 +52,6 @@ WlShellIntegration::WlShellIntegration(QWaylandQuickShellSurfaceItem *item)
     : QWaylandQuickShellIntegration(item)
     , m_item(item)
     , m_shellSurface(qobject_cast<QWaylandWlShellSurface *>(item->shellSurface()))
-    , grabberState(GrabberState::Default)
-    , isPopup(false)
-    , currentState(State::Windowed)
-    , nextState(State::Windowed)
 {
     m_item->setSurface(m_shellSurface->surface());
     connect(m_shellSurface.data(), &QWaylandWlShellSurface::startMove, this, &WlShellIntegration::handleStartMove);
diff --git a/src/compositor/extensions/qwaylandwlshellintegration_p.h b/src/compositor/extensions/qwaylandwlshellintegration_p.h
index 9a2e5a3a2..7b9569122 100644
--- a/src/compositor/extensions/qwaylandwlshellintegration_p.h
+++ b/src/compositor/extensions/qwaylandwlshellintegration_p.h
@@ -94,7 +94,7 @@ private:
 
     QWaylandQuickShellSurfaceItem *m_item;
     QPointer<QWaylandWlShellSurface> m_shellSurface;
-    GrabberState grabberState;
+    GrabberState grabberState = GrabberState::Default;
     struct {
         QWaylandSeat *seat;
         QPointF initialOffset;
@@ -108,7 +108,7 @@ private:
         bool initialized;
     } resizeState;
 
-    bool isPopup;
+    bool isPopup = false;
 
     enum class State {
         Windowed,
@@ -116,8 +116,8 @@ private:
         FullScreen
     };
 
-    State currentState;
-    State nextState;
+    State currentState = State::Windowed;
+    State nextState = State::Windowed;
     QPointF normalPosition;
     QPointF finalPosition;
 };
diff --git a/src/compositor/extensions/qwaylandxdgshellv5.cpp b/src/compositor/extensions/qwaylandxdgshellv5.cpp
index b5db226c2..13a95e17d 100644
--- a/src/compositor/extensions/qwaylandxdgshellv5.cpp
+++ b/src/compositor/extensions/qwaylandxdgshellv5.cpp
@@ -60,8 +60,6 @@ QWaylandSurfaceRole QWaylandXdgSurfaceV5Private::s_role("xdg_surface");
 QWaylandSurfaceRole QWaylandXdgPopupV5Private::s_role("xdg_popup");
 
 QWaylandXdgShellV5Private::QWaylandXdgShellV5Private()
-    : QWaylandCompositorExtensionPrivate()
-    , xdg_shell()
 {
 }
 
@@ -223,14 +221,7 @@ void QWaylandXdgShellV5Private::xdg_shell_pong(Resource *resource, uint32_t seri
 }
 
 QWaylandXdgSurfaceV5Private::QWaylandXdgSurfaceV5Private()
-    : QWaylandCompositorExtensionPrivate()
-    , xdg_surface()
-    , m_xdgShell(nullptr)
-    , m_surface(nullptr)
-    , m_parentSurface(nullptr)
-    , m_windowType(Qt::WindowType::Window)
-    , m_unsetWindowGeometry(true)
-    , m_lastAckedConfigure({{}, QSize(0, 0), 0})
+    : m_lastAckedConfigure({{}, QSize(0, 0), 0})
 {
 }
 
@@ -490,11 +481,6 @@ void QWaylandXdgSurfaceV5Private::xdg_surface_set_window_geometry(Resource *reso
 }
 
 QWaylandXdgPopupV5Private::QWaylandXdgPopupV5Private()
-    : QWaylandCompositorExtensionPrivate()
-    , xdg_popup()
-    , m_surface(nullptr)
-    , m_parentSurface(nullptr)
-    , m_xdgShell(nullptr)
 {
 }
 
diff --git a/src/compositor/extensions/qwaylandxdgshellv5_p.h b/src/compositor/extensions/qwaylandxdgshellv5_p.h
index 9b14f525d..b0b51698d 100644
--- a/src/compositor/extensions/qwaylandxdgshellv5_p.h
+++ b/src/compositor/extensions/qwaylandxdgshellv5_p.h
@@ -116,16 +116,16 @@ public:
     void setWindowType(Qt::WindowType windowType);
 
 private:
-    QWaylandXdgShellV5 *m_xdgShell;
-    QWaylandSurface *m_surface;
-    QWaylandXdgSurfaceV5 *m_parentSurface;
+    QWaylandXdgShellV5 *m_xdgShell = nullptr;
+    QWaylandSurface *m_surface = nullptr;
+    QWaylandXdgSurfaceV5 *m_parentSurface = nullptr;
 
-    Qt::WindowType m_windowType;
+    Qt::WindowType m_windowType = Qt::WindowType::Window;
 
     QString m_title;
     QString m_appId;
     QRect m_windowGeometry;
-    bool m_unsetWindowGeometry;
+    bool m_unsetWindowGeometry = true;
 
     QList<ConfigureEvent> m_pendingConfigures;
     ConfigureEvent m_lastAckedConfigure;
@@ -166,9 +166,9 @@ public:
     QWaylandXdgPopupV5Private();
     static QWaylandXdgPopupV5Private *get(QWaylandXdgPopupV5 *xdgPopup) { return xdgPopup->d_func(); }
 
-    QWaylandSurface *m_surface;
-    QWaylandSurface *m_parentSurface;
-    QWaylandXdgShellV5 *m_xdgShell;
+    QWaylandSurface *m_surface = nullptr;
+    QWaylandSurface *m_parentSurface = nullptr;
+    QWaylandXdgShellV5 *m_xdgShell = nullptr;
     QPoint m_position;
 
     void xdg_popup_destroy_resource(Resource *resource) override;
diff --git a/src/compositor/extensions/qwaylandxdgshellv6.cpp b/src/compositor/extensions/qwaylandxdgshellv6.cpp
index 4b1d46b8a..3485f80a4 100644
--- a/src/compositor/extensions/qwaylandxdgshellv6.cpp
+++ b/src/compositor/extensions/qwaylandxdgshellv6.cpp
@@ -54,8 +54,6 @@
 QT_BEGIN_NAMESPACE
 
 QWaylandXdgShellV6Private::QWaylandXdgShellV6Private()
-    : QWaylandCompositorExtensionPrivate()
-    , zxdg_shell_v6()
 {
 }
 
@@ -288,14 +286,6 @@ void QWaylandXdgShellV6::handleFocusChanged(QWaylandSurface *newSurface, QWaylan
 }
 
 QWaylandXdgSurfaceV6Private::QWaylandXdgSurfaceV6Private()
-    : QWaylandCompositorExtensionPrivate()
-    , zxdg_surface_v6()
-    , m_xdgShell(nullptr)
-    , m_surface(nullptr)
-    , m_toplevel(nullptr)
-    , m_popup(nullptr)
-    , m_unsetWindowGeometry(true)
-    , m_windowType(Qt::WindowType::Window)
 {
 }
 
@@ -1097,8 +1087,6 @@ QWaylandSurfaceRole QWaylandXdgToplevelV6Private::s_role("zxdg_toplevel_v6");
 
 QWaylandXdgToplevelV6Private::QWaylandXdgToplevelV6Private(QWaylandXdgSurfaceV6 *xdgSurface, const QWaylandResource &resource)
     : m_xdgSurface(xdgSurface)
-    , m_parentToplevel(nullptr)
-    , m_lastAckedConfigure({{}, QSize(0, 0), 0})
 {
     init(resource.resource());
 }
@@ -1756,10 +1744,7 @@ void QWaylandXdgPopupV6Private::zxdg_popup_v6_grab(QtWaylandServer::zxdg_popup_v
 QWaylandSurfaceRole QWaylandXdgPopupV6Private::s_role("zxdg_popup_v6");
 
 QWaylandXdgPositionerV6Data::QWaylandXdgPositionerV6Data()
-    : anchorEdges(0)
-    , gravityEdges(0)
-    , constraintAdjustments(ZXDG_POSITIONER_V6_CONSTRAINT_ADJUSTMENT_NONE)
-    , offset(0, 0)
+    : offset(0, 0)
 {}
 
 bool QWaylandXdgPositionerV6Data::isComplete() const
diff --git a/src/compositor/extensions/qwaylandxdgshellv6_p.h b/src/compositor/extensions/qwaylandxdgshellv6_p.h
index 98bcb70f7..191a936f9 100644
--- a/src/compositor/extensions/qwaylandxdgshellv6_p.h
+++ b/src/compositor/extensions/qwaylandxdgshellv6_p.h
@@ -60,9 +60,9 @@ QT_BEGIN_NAMESPACE
 struct Q_WAYLAND_COMPOSITOR_EXPORT QWaylandXdgPositionerV6Data {
     QSize size;
     QRect anchorRect;
-    Qt::Edges anchorEdges;
-    Qt::Edges gravityEdges;
-    uint constraintAdjustments;
+    Qt::Edges anchorEdges = 0;
+    Qt::Edges gravityEdges = 0;
+    uint constraintAdjustments = ZXDG_POSITIONER_V6_CONSTRAINT_ADJUSTMENT_NONE;
     QPoint offset;
     QWaylandXdgPositionerV6Data();
     bool isComplete() const;
@@ -112,15 +112,15 @@ public:
     void updateFallbackWindowGeometry();
 
 private:
-    QWaylandXdgShellV6 *m_xdgShell;
-    QWaylandSurface *m_surface;
+    QWaylandXdgShellV6 *m_xdgShell = nullptr;
+    QWaylandSurface *m_surface = nullptr;
 
-    QWaylandXdgToplevelV6 *m_toplevel;
-    QWaylandXdgPopupV6 *m_popup;
+    QWaylandXdgToplevelV6 *m_toplevel = nullptr;
+    QWaylandXdgPopupV6 *m_popup = nullptr;
     QRect m_windowGeometry;
-    bool m_unsetWindowGeometry;
+    bool m_unsetWindowGeometry = true;
     QMargins m_windowMargins;
-    Qt::WindowType m_windowType;
+    Qt::WindowType m_windowType = Qt::WindowType::Window;
 
     void zxdg_surface_v6_destroy_resource(Resource *resource) override;
     void zxdg_surface_v6_destroy(Resource *resource) override;
@@ -136,8 +136,8 @@ class Q_WAYLAND_COMPOSITOR_EXPORT QWaylandXdgToplevelV6Private : public QObjectP
 public:
     struct ConfigureEvent {
         QVector<QWaylandXdgToplevelV6::State> states;
-        QSize size;
-        uint serial;
+        QSize size = {0, 0};
+        uint serial = 0;
     };
 
     QWaylandXdgToplevelV6Private(QWaylandXdgSurfaceV6 *xdgSurface, const QWaylandResource& resource);
@@ -169,7 +169,7 @@ protected:
 
 public:
     QWaylandXdgSurfaceV6 *m_xdgSurface;
-    QWaylandXdgToplevelV6 *m_parentToplevel;
+    QWaylandXdgToplevelV6 *m_parentToplevel = nullptr;
     QList<ConfigureEvent> m_pendingConfigures;
     ConfigureEvent m_lastAckedConfigure;
     QString m_title;
diff --git a/src/compositor/extensions/qwlqttouch.cpp b/src/compositor/extensions/qwlqttouch.cpp
index 161ec6c18..6d1be4a35 100644
--- a/src/compositor/extensions/qwlqttouch.cpp
+++ b/src/compositor/extensions/qwlqttouch.cpp
@@ -52,8 +52,6 @@ TouchExtensionGlobal::TouchExtensionGlobal(QWaylandCompositor *compositor)
     : QWaylandCompositorExtensionTemplate(compositor)
     , QtWaylandServer::qt_touch_extension(compositor->display(), 1)
     , m_compositor(compositor)
-    , m_flags(BehaviorFlag::None)
-    , m_resources()
     , m_posData(maxRawPos * 2)
 {
 }
diff --git a/src/compositor/extensions/qwlqttouch_p.h b/src/compositor/extensions/qwlqttouch_p.h
index e605c89e1..3f046a576 100644
--- a/src/compositor/extensions/qwlqttouch_p.h
+++ b/src/compositor/extensions/qwlqttouch_p.h
@@ -94,7 +94,7 @@ protected:
 
 private:
     QWaylandCompositor *m_compositor;
-    BehaviorFlags m_flags;
+    BehaviorFlags m_flags = BehaviorFlag::None;
     QList<Resource *> m_resources;
     QVector<float> m_posData;
 };
diff --git a/src/compositor/global/qwaylandcompositorextension_p.h b/src/compositor/global/qwaylandcompositorextension_p.h
index 68f817aa6..6ec810988 100644
--- a/src/compositor/global/qwaylandcompositorextension_p.h
+++ b/src/compositor/global/qwaylandcompositorextension_p.h
@@ -63,16 +63,13 @@ class Q_WAYLAND_COMPOSITOR_EXPORT QWaylandCompositorExtensionPrivate : public QO
 
 public:
     QWaylandCompositorExtensionPrivate()
-        : QObjectPrivate()
-        , extension_container(nullptr)
-        , initialized(false)
     {
     }
 
     static QWaylandCompositorExtensionPrivate *get(QWaylandCompositorExtension *extension) { return extension->d_func(); }
 
-    QWaylandObject *extension_container;
-    bool initialized;
+    QWaylandObject *extension_container = nullptr;
+    bool initialized = false;
 };
 
 QT_END_NAMESPACE
diff --git a/src/compositor/hardware_integration/qwlclientbufferintegration.cpp b/src/compositor/hardware_integration/qwlclientbufferintegration.cpp
index 3f4d4a412..7407aca58 100644
--- a/src/compositor/hardware_integration/qwlclientbufferintegration.cpp
+++ b/src/compositor/hardware_integration/qwlclientbufferintegration.cpp
@@ -44,7 +44,6 @@ QT_BEGIN_NAMESPACE
 namespace QtWayland {
 
 ClientBufferIntegration::ClientBufferIntegration()
-    : m_compositor(nullptr)
 {
 }
 
diff --git a/src/compositor/hardware_integration/qwlclientbufferintegration_p.h b/src/compositor/hardware_integration/qwlclientbufferintegration_p.h
index 1b54786f2..13a69fce9 100644
--- a/src/compositor/hardware_integration/qwlclientbufferintegration_p.h
+++ b/src/compositor/hardware_integration/qwlclientbufferintegration_p.h
@@ -79,7 +79,7 @@ public:
     virtual ClientBuffer *createBufferFor(struct ::wl_resource *buffer) = 0;
 
 protected:
-    QWaylandCompositor *m_compositor;
+    QWaylandCompositor *m_compositor = nullptr;
 };
 
 }
diff --git a/src/compositor/wayland_wrapper/qwlbuffermanager.cpp b/src/compositor/wayland_wrapper/qwlbuffermanager.cpp
index 86331a744..d5c661e93 100644
--- a/src/compositor/wayland_wrapper/qwlbuffermanager.cpp
+++ b/src/compositor/wayland_wrapper/qwlbuffermanager.cpp
@@ -57,13 +57,12 @@ BufferManager::BufferManager(QWaylandCompositor *compositor)
 struct buffer_manager_destroy_listener : wl_listener
 {
     buffer_manager_destroy_listener()
-        : d(nullptr)
     {
         notify = BufferManager::destroy_listener_callback;
         wl_list_init(&this->link);
     }
 
-    BufferManager *d;
+    BufferManager *d = nullptr;
 };
 
 ClientBuffer *BufferManager::getBuffer(wl_resource *buffer_resource)
diff --git a/src/compositor/wayland_wrapper/qwlclientbuffer.cpp b/src/compositor/wayland_wrapper/qwlclientbuffer.cpp
index 7d7e787c4..7df9ead3c 100644
--- a/src/compositor/wayland_wrapper/qwlclientbuffer.cpp
+++ b/src/compositor/wayland_wrapper/qwlclientbuffer.cpp
@@ -58,9 +58,6 @@ namespace QtWayland {
 
 ClientBuffer::ClientBuffer(struct ::wl_resource *buffer)
     : m_buffer(buffer)
-    , m_textureDirty(false)
-    , m_committed(false)
-    , m_destroyed(false)
 {
 }
 
@@ -117,9 +114,6 @@ QWaylandBufferRef::BufferFormatEgl ClientBuffer::bufferFormatEgl() const
 
 SharedMemoryBuffer::SharedMemoryBuffer(wl_resource *bufferResource)
     : ClientBuffer(bufferResource)
-#if QT_CONFIG(opengl)
-    , m_shmTexture(nullptr)
-#endif
 {
 
 }
diff --git a/src/compositor/wayland_wrapper/qwlclientbuffer_p.h b/src/compositor/wayland_wrapper/qwlclientbuffer_p.h
index 5a66a67a7..5f3475ed7 100644
--- a/src/compositor/wayland_wrapper/qwlclientbuffer_p.h
+++ b/src/compositor/wayland_wrapper/qwlclientbuffer_p.h
@@ -114,11 +114,11 @@ protected:
 
     struct ::wl_resource *m_buffer;
     QRegion m_damage;
-    bool m_textureDirty;
+    bool m_textureDirty = false;
 
 private:
-    bool m_committed;
-    bool m_destroyed;
+    bool m_committed = false;
+    bool m_destroyed = false;
 
     QAtomicInt m_refCount;
 
@@ -139,7 +139,7 @@ public:
     QOpenGLTexture *toOpenGlTexture(int plane = 0) override;
 
 private:
-    QOpenGLTexture *m_shmTexture;
+    QOpenGLTexture *m_shmTexture = nullptr;
 #endif
 };
 
diff --git a/src/compositor/wayland_wrapper/qwldatadevice.cpp b/src/compositor/wayland_wrapper/qwldatadevice.cpp
index 3b557a109..6dc1355d5 100644
--- a/src/compositor/wayland_wrapper/qwldatadevice.cpp
+++ b/src/compositor/wayland_wrapper/qwldatadevice.cpp
@@ -61,18 +61,8 @@ QT_BEGIN_NAMESPACE
 namespace QtWayland {
 
 DataDevice::DataDevice(QWaylandSeat *seat)
-    : wl_data_device()
-    , m_compositor(seat->compositor())
+    : m_compositor(seat->compositor())
     , m_seat(seat)
-    , m_selectionSource(nullptr)
-#if QT_CONFIG(draganddrop)
-    , m_dragClient(nullptr)
-    , m_dragDataSource(nullptr)
-    , m_dragFocus(nullptr)
-    , m_dragFocusResource(nullptr)
-    , m_dragIcon(nullptr)
-    , m_dragOrigin(nullptr)
-#endif
 {
 }
 
diff --git a/src/compositor/wayland_wrapper/qwldatadevice_p.h b/src/compositor/wayland_wrapper/qwldatadevice_p.h
index d041f0158..4cb492509 100644
--- a/src/compositor/wayland_wrapper/qwldatadevice_p.h
+++ b/src/compositor/wayland_wrapper/qwldatadevice_p.h
@@ -99,17 +99,17 @@ private:
     QWaylandCompositor *m_compositor;
     QWaylandSeat *m_seat;
 
-    DataSource *m_selectionSource;
+    DataSource *m_selectionSource = nullptr;
 
 #if QT_CONFIG(draganddrop)
-    struct ::wl_client *m_dragClient;
-    DataSource *m_dragDataSource;
+    struct ::wl_client *m_dragClient = nullptr;
+    DataSource *m_dragDataSource = nullptr;
 
-    QWaylandSurface *m_dragFocus;
-    Resource *m_dragFocusResource;
+    QWaylandSurface *m_dragFocus = nullptr;
+    Resource *m_dragFocusResource = nullptr;
 
-    QWaylandSurface *m_dragIcon;
-    QWaylandSurface *m_dragOrigin;
+    QWaylandSurface *m_dragIcon = nullptr;
+    QWaylandSurface *m_dragOrigin = nullptr;
 #endif
 };
 
diff --git a/src/compositor/wayland_wrapper/qwldatadevicemanager.cpp b/src/compositor/wayland_wrapper/qwldatadevicemanager.cpp
index 0c0855d24..acca08e07 100644
--- a/src/compositor/wayland_wrapper/qwldatadevicemanager.cpp
+++ b/src/compositor/wayland_wrapper/qwldatadevicemanager.cpp
@@ -59,12 +59,8 @@ QT_BEGIN_NAMESPACE
 namespace QtWayland {
 
 DataDeviceManager::DataDeviceManager(QWaylandCompositor *compositor)
-    : QObject(nullptr)
-    , wl_data_device_manager(compositor->display(), 1)
+    : wl_data_device_manager(compositor->display(), 1)
     , m_compositor(compositor)
-    , m_current_selection_source(nullptr)
-    , m_retainedReadNotifier(nullptr)
-    , m_compositorOwnsSelection(false)
 {
 }
 
diff --git a/src/compositor/wayland_wrapper/qwldatadevicemanager_p.h b/src/compositor/wayland_wrapper/qwldatadevicemanager_p.h
index d6ace5c00..9c6672db6 100644
--- a/src/compositor/wayland_wrapper/qwldatadevicemanager_p.h
+++ b/src/compositor/wayland_wrapper/qwldatadevicemanager_p.h
@@ -104,15 +104,15 @@ private:
     QWaylandCompositor *m_compositor;
     QList<DataDevice *> m_data_device_list;
 
-    DataSource *m_current_selection_source;
+    DataSource *m_current_selection_source = nullptr;
 
     QMimeData m_retainedData;
-    QSocketNotifier *m_retainedReadNotifier;
+    QSocketNotifier *m_retainedReadNotifier = nullptr;
     QList<QSocketNotifier *> m_obsoleteRetainedReadNotifiers;
     int m_retainedReadIndex;
     QByteArray m_retainedReadBuf;
 
-    bool m_compositorOwnsSelection;
+    bool m_compositorOwnsSelection = false;
 
 
     static void comp_accept(struct wl_client *client,
diff --git a/src/compositor/wayland_wrapper/qwldatasource.cpp b/src/compositor/wayland_wrapper/qwldatasource.cpp
index 2d523dad9..baa47d6fc 100644
--- a/src/compositor/wayland_wrapper/qwldatasource.cpp
+++ b/src/compositor/wayland_wrapper/qwldatasource.cpp
@@ -52,8 +52,6 @@ namespace QtWayland {
 DataSource::DataSource(struct wl_client *client, uint32_t id, uint32_t time)
     : QtWaylandServer::wl_data_source(client, id, 1)
     , m_time(time)
-    , m_device(nullptr)
-    , m_manager(nullptr)
 {
 }
 
diff --git a/src/compositor/wayland_wrapper/qwldatasource_p.h b/src/compositor/wayland_wrapper/qwldatasource_p.h
index cf54d762f..d5437a301 100644
--- a/src/compositor/wayland_wrapper/qwldatasource_p.h
+++ b/src/compositor/wayland_wrapper/qwldatasource_p.h
@@ -92,8 +92,8 @@ private:
     uint32_t m_time;
     QList<QString> m_mimeTypes;
 
-    DataDevice *m_device;
-    DataDeviceManager *m_manager;
+    DataDevice *m_device = nullptr;
+    DataDeviceManager *m_manager = nullptr;
 };
 
 }
diff --git a/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglintegration.cpp b/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglintegration.cpp
index 430b455f4..4478b9fdf 100644
--- a/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglintegration.cpp
+++ b/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglintegration.cpp
@@ -53,7 +53,6 @@ QT_BEGIN_NAMESPACE
 namespace QtWaylandClient {
 
 QWaylandBrcmEglIntegration::QWaylandBrcmEglIntegration()
-    : m_waylandDisplay(0)
 {
     qDebug() << "Using Brcm-EGL";
 }
diff --git a/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglintegration.h b/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglintegration.h
index 0a913bcdf..8d89ebf74 100644
--- a/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglintegration.h
+++ b/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglintegration.h
@@ -85,7 +85,7 @@ public:
 private:
     static void wlDisplayHandleGlobal(void *data, struct wl_registry *registry, uint32_t id, const QString &interface, uint32_t version);
 
-    struct wl_display *m_waylandDisplay;
+    struct wl_display *m_waylandDisplay = nullptr;
     struct qt_brcm *m_waylandBrcm;
 
     EGLDisplay m_eglDisplay;
diff --git a/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglwindow.cpp b/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglwindow.cpp
index f2709983e..6b3c614a5 100644
--- a/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglwindow.cpp
+++ b/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglwindow.cpp
@@ -67,7 +67,6 @@ public:
                        int count,
                        struct wl_event_queue *eventQueue)
         : m_size(size)
-        , m_released(true)
         , m_display(display)
         , m_eventQueue(eventQueue)
     {
@@ -119,7 +118,7 @@ public:
 private:
 
     QSize m_size;
-    bool m_released;
+    bool m_released = true;
     wl_array m_array;
     EGLint *m_data;
     QWaylandDisplay *m_display;
@@ -129,11 +128,8 @@ private:
 QWaylandBrcmEglWindow::QWaylandBrcmEglWindow(QWindow *window)
     : QWaylandWindow(window)
     , m_eglIntegration(static_cast<QWaylandBrcmEglIntegration *>(mDisplay->clientBufferIntegration()))
-    , m_eglConfig(0)
     , m_format(window->format())
     , m_eventQueue(wl_display_create_queue(mDisplay->wl_display()))
-    , m_current(0)
-    , m_count(0)
 {
 }
 
diff --git a/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglwindow.h b/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglwindow.h
index be88df9af..28376669d 100644
--- a/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglwindow.h
+++ b/src/hardwareintegration/client/brcm-egl/qwaylandbrcmeglwindow.h
@@ -77,7 +77,7 @@ private:
 
     const QWaylandWindow *m_parentWindow;
 
-    EGLConfig m_eglConfig;
+    EGLConfig m_eglConfig = 0;
 
     EGLint m_globalImages[3*5];
     EGLSurface m_eglSurfaces[3];
@@ -87,8 +87,8 @@ private:
 
     struct wl_event_queue *m_eventQueue;
 
-    int m_current;
-    int m_count;
+    int m_current = 0;
+    int m_count = 0;
 };
 
 }
diff --git a/src/hardwareintegration/client/drm-egl-server/drmeglserverbufferintegration.cpp b/src/hardwareintegration/client/drm-egl-server/drmeglserverbufferintegration.cpp
index fe2adbf56..754196468 100644
--- a/src/hardwareintegration/client/drm-egl-server/drmeglserverbufferintegration.cpp
+++ b/src/hardwareintegration/client/drm-egl-server/drmeglserverbufferintegration.cpp
@@ -55,8 +55,7 @@ DrmServerBuffer::DrmServerBuffer(DrmEglServerBufferIntegration *integration
                                 , int32_t height
                                 , int32_t stride
                                 , int32_t format)
-    : QWaylandServerBuffer()
-    , m_integration(integration)
+    : m_integration(integration)
 {
     m_size = QSize(width, height);
     EGLint egl_format;
diff --git a/src/hardwareintegration/client/libhybris-egl-server/libhybriseglserverbufferintegration.cpp b/src/hardwareintegration/client/libhybris-egl-server/libhybriseglserverbufferintegration.cpp
index 51b904e75..252ceb698 100644
--- a/src/hardwareintegration/client/libhybris-egl-server/libhybriseglserverbufferintegration.cpp
+++ b/src/hardwareintegration/client/libhybris-egl-server/libhybriseglserverbufferintegration.cpp
@@ -60,7 +60,6 @@ LibHybrisServerBuffer::LibHybrisServerBuffer(LibHybrisEglServerBufferIntegration
                                             , int32_t format)
     : QWaylandServerBuffer()
     , m_integration(integration)
-    , m_texture(nullptr)
     , m_stride(stride)
     , m_hybrisFormat(format)
 {
diff --git a/src/hardwareintegration/client/libhybris-egl-server/libhybriseglserverbufferintegration.h b/src/hardwareintegration/client/libhybris-egl-server/libhybriseglserverbufferintegration.h
index b3c9c464d..1ba38e6e4 100644
--- a/src/hardwareintegration/client/libhybris-egl-server/libhybriseglserverbufferintegration.h
+++ b/src/hardwareintegration/client/libhybris-egl-server/libhybriseglserverbufferintegration.h
@@ -83,7 +83,7 @@ protected:
 private:
     LibHybrisEglServerBufferIntegration *m_integration;
     EGLImageKHR m_image;
-    QOpenGLTexture *m_texture;
+    QOpenGLTexture *m_texture = nullptr;
     int m_numFds;
     QVector<int32_t> m_ints;
     QVector<int32_t> m_fds;
diff --git a/src/hardwareintegration/client/shm-emulation-server/shmserverbufferintegration.cpp b/src/hardwareintegration/client/shm-emulation-server/shmserverbufferintegration.cpp
index bc597ebf8..0c43b089a 100644
--- a/src/hardwareintegration/client/shm-emulation-server/shmserverbufferintegration.cpp
+++ b/src/hardwareintegration/client/shm-emulation-server/shmserverbufferintegration.cpp
@@ -89,9 +89,7 @@ static QOpenGLTexture *createTextureFromShm(const QString &key, int w, int h, in
 
 namespace QtWaylandClient {
 ShmServerBuffer::ShmServerBuffer(ShmServerBufferIntegration *integration, const QString &key, int32_t width, int32_t height, int32_t bytes_per_line, int32_t format)
-    : QWaylandServerBuffer()
-    , m_integration(integration)
-    , m_texture(nullptr)
+    : m_integration(integration)
     , m_key(key)
     , m_bpl(bytes_per_line)
     , m_format(format)
diff --git a/src/hardwareintegration/client/shm-emulation-server/shmserverbufferintegration.h b/src/hardwareintegration/client/shm-emulation-server/shmserverbufferintegration.h
index ce4032ba4..788344ff6 100644
--- a/src/hardwareintegration/client/shm-emulation-server/shmserverbufferintegration.h
+++ b/src/hardwareintegration/client/shm-emulation-server/shmserverbufferintegration.h
@@ -62,7 +62,7 @@ public:
     QOpenGLTexture* toOpenGlTexture() override;
 private:
     ShmServerBufferIntegration *m_integration;
-    QOpenGLTexture *m_texture;
+    QOpenGLTexture *m_texture = nullptr;
     QString m_key;
     int m_bpl;
     int m_format;
diff --git a/src/hardwareintegration/client/wayland-egl/qwaylandeglclientbufferintegration.cpp b/src/hardwareintegration/client/wayland-egl/qwaylandeglclientbufferintegration.cpp
index 8a1009fa8..4b3a635c7 100644
--- a/src/hardwareintegration/client/wayland-egl/qwaylandeglclientbufferintegration.cpp
+++ b/src/hardwareintegration/client/wayland-egl/qwaylandeglclientbufferintegration.cpp
@@ -64,9 +64,6 @@ static const char *qwaylandegl_threadedgl_blacklist_vendor[] = {
 };
 
 QWaylandEglClientBufferIntegration::QWaylandEglClientBufferIntegration()
-    : m_display(0)
-    , m_eglDisplay(EGL_NO_DISPLAY)
-    , m_supportsThreading(false)
 {
     qDebug() << "Using Wayland-EGL";
 }
diff --git a/src/hardwareintegration/client/wayland-egl/qwaylandeglclientbufferintegration.h b/src/hardwareintegration/client/wayland-egl/qwaylandeglclientbufferintegration.h
index 427a30d8e..93edfcc58 100644
--- a/src/hardwareintegration/client/wayland-egl/qwaylandeglclientbufferintegration.h
+++ b/src/hardwareintegration/client/wayland-egl/qwaylandeglclientbufferintegration.h
@@ -72,10 +72,10 @@ public:
     EGLDisplay eglDisplay() const;
 
 private:
-    QWaylandDisplay *m_display;
+    QWaylandDisplay *m_display = nullptr;
 
-    EGLDisplay m_eglDisplay;
-    bool m_supportsThreading;
+    EGLDisplay m_eglDisplay = EGL_NO_DISPLAY;
+    bool m_supportsThreading = false;
 };
 
 QT_END_NAMESPACE
diff --git a/src/hardwareintegration/client/wayland-egl/qwaylandeglwindow.cpp b/src/hardwareintegration/client/wayland-egl/qwaylandeglwindow.cpp
index 87f3e2d4e..870b71c1a 100644
--- a/src/hardwareintegration/client/wayland-egl/qwaylandeglwindow.cpp
+++ b/src/hardwareintegration/client/wayland-egl/qwaylandeglwindow.cpp
@@ -57,10 +57,6 @@ namespace QtWaylandClient {
 QWaylandEglWindow::QWaylandEglWindow(QWindow *window)
     : QWaylandWindow(window)
     , m_clientBufferIntegration(static_cast<QWaylandEglClientBufferIntegration *>(mDisplay->clientBufferIntegration()))
-    , m_waylandEglWindow(0)
-    , m_eglSurface(0)
-    , m_contentFBO(0)
-    , m_resize(false)
 {
     QSurfaceFormat fmt = window->requestedFormat();
     if (mDisplay->supportsWindowDecoration())
diff --git a/src/hardwareintegration/client/wayland-egl/qwaylandeglwindow.h b/src/hardwareintegration/client/wayland-egl/qwaylandeglwindow.h
index 77aee56dc..94947365c 100644
--- a/src/hardwareintegration/client/wayland-egl/qwaylandeglwindow.h
+++ b/src/hardwareintegration/client/wayland-egl/qwaylandeglwindow.h
@@ -82,14 +82,14 @@ private Q_SLOTS:
 
 private:
     QWaylandEglClientBufferIntegration *m_clientBufferIntegration;
-    struct wl_egl_window *m_waylandEglWindow;
+    struct wl_egl_window *m_waylandEglWindow = nullptr;
 
     const QWaylandWindow *m_parentWindow;
 
-    EGLSurface m_eglSurface;
+    EGLSurface m_eglSurface = EGL_NO_SURFACE;
     EGLConfig m_eglConfig;
-    mutable QOpenGLFramebufferObject *m_contentFBO;
-    mutable bool m_resize;
+    mutable bool m_resize = false;
+    mutable QOpenGLFramebufferObject *m_contentFBO = nullptr;
 
     QSurfaceFormat m_format;
 };
diff --git a/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp b/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp
index 967028861..740ad6b10 100644
--- a/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp
+++ b/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp
@@ -229,9 +229,6 @@ QWaylandGLContext::QWaylandGLContext(EGLDisplay eglDisplay, QWaylandDisplay *dis
     : QPlatformOpenGLContext()
     , m_eglDisplay(eglDisplay)
     , m_display(display)
-    , m_blitter(0)
-    , mUseNativeDefaultFbo(false)
-    , mSupportNonBlockingSwap(true)
 {
     QSurfaceFormat fmt = format;
     if (static_cast<QWaylandIntegration *>(QGuiApplicationPrivate::platformIntegration())->display()->supportsWindowDecoration())
diff --git a/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.h b/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.h
index 6d9887de6..af1c4e04d 100644
--- a/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.h
+++ b/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.h
@@ -89,10 +89,10 @@ private:
     EGLContext m_shareEGLContext;
     EGLConfig m_config;
     QSurfaceFormat m_format;
-    DecorationsBlitter *m_blitter;
-    bool mUseNativeDefaultFbo;
+    DecorationsBlitter *m_blitter = nullptr;
+    bool mUseNativeDefaultFbo = false;
     uint m_api;
-    bool mSupportNonBlockingSwap;
+    bool mSupportNonBlockingSwap = true;
 
     friend class DecorationsBlitter;
 };
diff --git a/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglclientbufferintegration.cpp b/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglclientbufferintegration.cpp
index 2a7de6b72..aa5367e02 100644
--- a/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglclientbufferintegration.cpp
+++ b/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglclientbufferintegration.cpp
@@ -54,8 +54,6 @@ namespace QtWaylandClient {
 
 QWaylandXCompositeEGLClientBufferIntegration::QWaylandXCompositeEGLClientBufferIntegration()
     : QWaylandClientBufferIntegration()
-    , mWaylandDisplay(0)
-    , mDisplay(0)
 {
     qDebug() << "Using XComposite-EGL";
 }
diff --git a/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglclientbufferintegration.h b/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglclientbufferintegration.h
index cdc071e55..3742e1f56 100644
--- a/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglclientbufferintegration.h
+++ b/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglclientbufferintegration.h
@@ -92,10 +92,10 @@ public:
     bool supportsWindowDecoration() const override { return false; }
 
 private:
-    QWaylandDisplay *mWaylandDisplay;
+    QWaylandDisplay *mWaylandDisplay = nullptr;
     struct qt_xcomposite *mWaylandComposite;
 
-    Display *mDisplay;
+    Display *mDisplay = nullptr;
     EGLDisplay mEglDisplay;
     int mScreen;
     Window mRootWindow;
diff --git a/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglwindow.cpp b/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglwindow.cpp
index 9c3dee3fc..57a7ba7b6 100644
--- a/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglwindow.cpp
+++ b/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglwindow.cpp
@@ -57,10 +57,7 @@ namespace QtWaylandClient {
 QWaylandXCompositeEGLWindow::QWaylandXCompositeEGLWindow(QWindow *window, QWaylandXCompositeEGLClientBufferIntegration *glxIntegration)
     : QWaylandWindow(window)
     , m_glxIntegration(glxIntegration)
-    , m_buffer(0)
-    , m_xWindow(0)
     , m_config(q_configFromGLFormat(glxIntegration->eglDisplay(), window->format(), true, EGL_WINDOW_BIT | EGL_PIXMAP_BIT))
-    , m_surface(0)
 {
 }
 
diff --git a/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglwindow.h b/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglwindow.h
index 90b4cc73e..d90159fa7 100644
--- a/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglwindow.h
+++ b/src/hardwareintegration/client/xcomposite-egl/qwaylandxcompositeeglwindow.h
@@ -66,11 +66,11 @@ private:
     void createEglSurface();
 
     QWaylandXCompositeEGLClientBufferIntegration *m_glxIntegration;
-    QWaylandBuffer *m_buffer;
+    QWaylandBuffer *m_buffer = nullptr;
 
-    Window m_xWindow;
+    Window m_xWindow = 0;
     EGLConfig m_config;
-    EGLSurface m_surface;
+    EGLSurface m_surface = EGL_NO_SURFACE;
 };
 
 }
diff --git a/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxintegration.cpp b/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxintegration.cpp
index dbd7761e3..090cfb8a0 100644
--- a/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxintegration.cpp
+++ b/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxintegration.cpp
@@ -52,11 +52,6 @@ QT_BEGIN_NAMESPACE
 namespace QtWaylandClient {
 
 QWaylandXCompositeGLXIntegration::QWaylandXCompositeGLXIntegration()
-    : mWaylandDisplay(0)
-    , mWaylandComposite(0)
-    , mDisplay(0)
-    , mScreen(0)
-    , mRootWindow(0)
 {
     qDebug() << "Using XComposite-GLX";
 }
diff --git a/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxintegration.h b/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxintegration.h
index 288bf3111..746678f7a 100644
--- a/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxintegration.h
+++ b/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxintegration.h
@@ -86,12 +86,12 @@ public:
     bool supportsWindowDecoration() const override { return false; }
 
 private:
-    QWaylandDisplay *mWaylandDisplay;
-    struct qt_xcomposite *mWaylandComposite;
+    QWaylandDisplay *mWaylandDisplay = nullptr;
+    struct qt_xcomposite *mWaylandComposite = nullptr;
 
-    Display *mDisplay;
-    int mScreen;
-    Window mRootWindow;
+    Display *mDisplay = nullptr;
+    int mScreen = 0;
+    Window mRootWindow = 0;
 
     static void wlDisplayHandleGlobal(void *data, struct wl_registry *registry, uint32_t id,
                                       const QString &interface, uint32_t version);
diff --git a/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxwindow.cpp b/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxwindow.cpp
index 9cca9e46e..2b491e24d 100644
--- a/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxwindow.cpp
+++ b/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxwindow.cpp
@@ -54,9 +54,7 @@ namespace QtWaylandClient {
 QWaylandXCompositeGLXWindow::QWaylandXCompositeGLXWindow(QWindow *window, QWaylandXCompositeGLXIntegration *glxIntegration)
     : QWaylandWindow(window)
     , m_glxIntegration(glxIntegration)
-    , m_xWindow(0)
     , m_config(qglx_findConfig(glxIntegration->xDisplay(), glxIntegration->screen(), window->format(), GLX_WINDOW_BIT | GLX_PIXMAP_BIT))
-    , mBuffer(0)
 {
 }
 
diff --git a/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxwindow.h b/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxwindow.h
index aeb5c14ec..c2df592ee 100644
--- a/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxwindow.h
+++ b/src/hardwareintegration/client/xcomposite-glx/qwaylandxcompositeglxwindow.h
@@ -69,9 +69,9 @@ private:
 
     QWaylandXCompositeGLXIntegration *m_glxIntegration;
 
-    Window m_xWindow;
+    Window m_xWindow = 0;
     GLXFBConfig m_config;
-    QWaylandBuffer *mBuffer;
+    QWaylandBuffer *mBuffer = nullptr;
 };
 
 }
diff --git a/src/hardwareintegration/compositor/brcm-egl/brcmbuffer.cpp b/src/hardwareintegration/compositor/brcm-egl/brcmbuffer.cpp
index 768545772..f5573fefd 100644
--- a/src/hardwareintegration/compositor/brcm-egl/brcmbuffer.cpp
+++ b/src/hardwareintegration/compositor/brcm-egl/brcmbuffer.cpp
@@ -48,7 +48,6 @@ QT_BEGIN_NAMESPACE
 BrcmBuffer::BrcmBuffer(struct ::wl_client *client, uint32_t id, const QSize &size, EGLint *data, size_t count)
     : QtWaylandServer::wl_buffer(client, id, 1)
     , m_handle(count)
-    , m_invertedY(false)
     , m_size(size)
 {
     for (size_t i = 0; i < count; ++i)
diff --git a/src/hardwareintegration/compositor/brcm-egl/brcmbuffer.h b/src/hardwareintegration/compositor/brcm-egl/brcmbuffer.h
index 605adef7f..3028fbed5 100644
--- a/src/hardwareintegration/compositor/brcm-egl/brcmbuffer.h
+++ b/src/hardwareintegration/compositor/brcm-egl/brcmbuffer.h
@@ -70,7 +70,7 @@ protected:
 
 private:
     QVector<EGLint> m_handle;
-    bool m_invertedY;
+    bool m_invertedY = false;
     QSize m_size;
 };
 
diff --git a/src/hardwareintegration/compositor/brcm-egl/brcmeglintegration.cpp b/src/hardwareintegration/compositor/brcm-egl/brcmeglintegration.cpp
index 312dfbcfa..852ec3dee 100644
--- a/src/hardwareintegration/compositor/brcm-egl/brcmeglintegration.cpp
+++ b/src/hardwareintegration/compositor/brcm-egl/brcmeglintegration.cpp
@@ -60,15 +60,12 @@ QT_BEGIN_NAMESPACE
 class BrcmEglIntegrationPrivate
 {
 public:
-    BrcmEglIntegrationPrivate()
-        : egl_display(EGL_NO_DISPLAY)
-        , valid(false)
-    { }
+    BrcmEglIntegrationPrivate() = default;
 
     static BrcmEglIntegrationPrivate *get(BrcmEglIntegration *integration);
 
-    EGLDisplay egl_display;
-    bool valid;
+    EGLDisplay egl_display = EGL_NO_DISPLAY;
+    bool valid = false;
     PFNEGLQUERYGLOBALIMAGEBRCMPROC eglQueryGlobalImageBRCM;
     PFNGLEGLIMAGETARGETTEXTURE2DOESPROC glEGLImageTargetTexture2DOES;
     PFNEGLCREATEIMAGEKHRPROC eglCreateImageKHR;
@@ -76,9 +73,7 @@ public:
 };
 
 BrcmEglIntegration::BrcmEglIntegration()
-    : QtWayland::ClientBufferIntegration()
-    , QtWaylandServer::qt_brcm()
-    , d_ptr(new BrcmEglIntegrationPrivate)
+    : d_ptr(new BrcmEglIntegrationPrivate)
 {
 }
 
@@ -188,7 +183,6 @@ void BrcmEglIntegration::brcm_create_buffer(Resource *resource, uint32_t id, int
 BrcmEglClientBuffer::BrcmEglClientBuffer(BrcmEglIntegration *integration, wl_resource *buffer)
     : ClientBuffer(buffer)
     , m_integration(integration)
-    , m_texture(nullptr)
 {
 }
 
diff --git a/src/hardwareintegration/compositor/brcm-egl/brcmeglintegration.h b/src/hardwareintegration/compositor/brcm-egl/brcmeglintegration.h
index dea61b4bb..89e53bc30 100644
--- a/src/hardwareintegration/compositor/brcm-egl/brcmeglintegration.h
+++ b/src/hardwareintegration/compositor/brcm-egl/brcmeglintegration.h
@@ -79,8 +79,8 @@ public:
     QWaylandSurface::Origin origin() const override;
     QOpenGLTexture *toOpenGlTexture(int plane) override;
 private:
-    BrcmEglIntegration *m_integration;
-    QOpenGLTexture *m_texture;
+    BrcmEglIntegration *m_integration = nullptr;
+    QOpenGLTexture *m_texture = nullptr;
 };
 
 
diff --git a/src/hardwareintegration/compositor/drm-egl-server/drmeglserverbufferintegration.cpp b/src/hardwareintegration/compositor/drm-egl-server/drmeglserverbufferintegration.cpp
index c7dbe1bea..ef14aa2a2 100644
--- a/src/hardwareintegration/compositor/drm-egl-server/drmeglserverbufferintegration.cpp
+++ b/src/hardwareintegration/compositor/drm-egl-server/drmeglserverbufferintegration.cpp
@@ -47,7 +47,6 @@ QT_BEGIN_NAMESPACE
 DrmEglServerBuffer::DrmEglServerBuffer(DrmEglServerBufferIntegration *integration, const QImage &qimage, QtWayland::ServerBuffer::Format format)
     : QtWayland::ServerBuffer(qimage.size(),format)
     , m_integration(integration)
-    , m_texture(nullptr)
 {
     m_format = format;
 
diff --git a/src/hardwareintegration/compositor/drm-egl-server/drmeglserverbufferintegration.h b/src/hardwareintegration/compositor/drm-egl-server/drmeglserverbufferintegration.h
index e1cc8768f..b3bcc3109 100644
--- a/src/hardwareintegration/compositor/drm-egl-server/drmeglserverbufferintegration.h
+++ b/src/hardwareintegration/compositor/drm-egl-server/drmeglserverbufferintegration.h
@@ -89,7 +89,7 @@ private:
 
     int32_t m_name;
     int32_t m_stride;
-    QOpenGLTexture *m_texture;
+    QOpenGLTexture *m_texture = nullptr;
     QtWaylandServer::qt_drm_egl_server_buffer::format m_drm_format;
 };
 
diff --git a/src/hardwareintegration/compositor/libhybris-egl-server/libhybriseglserverbufferintegration.cpp b/src/hardwareintegration/compositor/libhybris-egl-server/libhybriseglserverbufferintegration.cpp
index de9e1cf6e..5a42c00dc 100644
--- a/src/hardwareintegration/compositor/libhybris-egl-server/libhybriseglserverbufferintegration.cpp
+++ b/src/hardwareintegration/compositor/libhybris-egl-server/libhybriseglserverbufferintegration.cpp
@@ -48,7 +48,6 @@ QT_BEGIN_NAMESPACE
 LibHybrisEglServerBuffer::LibHybrisEglServerBuffer(LibHybrisEglServerBufferIntegration *integration, const QImage &qimage, QtWayland::ServerBuffer::Format format)
     : QtWayland::ServerBuffer(qimage.size(),format)
     , m_integration(integration)
-    , m_texture(nullptr)
 {
     m_format = format;
 
diff --git a/src/hardwareintegration/compositor/libhybris-egl-server/libhybriseglserverbufferintegration.h b/src/hardwareintegration/compositor/libhybris-egl-server/libhybriseglserverbufferintegration.h
index 0e1593447..f99dacd99 100644
--- a/src/hardwareintegration/compositor/libhybris-egl-server/libhybriseglserverbufferintegration.h
+++ b/src/hardwareintegration/compositor/libhybris-egl-server/libhybriseglserverbufferintegration.h
@@ -91,7 +91,7 @@ private:
 
     int32_t m_name;
     int32_t m_stride;
-    QOpenGLTexture *m_texture;
+    QOpenGLTexture *m_texture = nullptr;
     QtWaylandServer::qt_libhybris_egl_server_buffer::format m_hybris_format;
     QVector<int32_t> m_ints;
     QVector<int32_t> m_fds;
diff --git a/src/hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp b/src/hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp
index a088027a3..6de664564 100644
--- a/src/hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp
+++ b/src/hardwareintegration/compositor/wayland-egl/waylandeglclientbufferintegration.cpp
@@ -151,7 +151,7 @@ egl_error_string(EGLint code)
 
 struct BufferState
 {
-    BufferState();
+    BufferState() = default;
 
     enum EglMode {
         ModeUninitialized,
@@ -159,14 +159,14 @@ struct BufferState
         ModeEGLStream
     };
 
-    EGLint egl_format;
+    EGLint egl_format = EGL_TEXTURE_RGBA;
     QVarLengthArray<EGLImageKHR, 3> egl_images;
     QOpenGLTexture *textures[3] = {};
-    EGLStreamKHR egl_stream;
+    EGLStreamKHR egl_stream = EGL_NO_STREAM_KHR;
 
-    bool isYInverted;
+    bool isYInverted = true;
     QSize size;
-    EglMode eglMode;
+    EglMode eglMode = ModeUninitialized;
 };
 
 class WaylandEglClientBufferIntegrationPrivate
@@ -181,22 +181,22 @@ public:
     void handleEglstreamTexture(WaylandEglClientBuffer *buffer, wl_resource *bufferHandle);
     void registerBuffer(struct ::wl_resource *buffer, BufferState state);
 
-    EGLDisplay egl_display;
-    bool valid;
-    bool display_bound;
+    EGLDisplay egl_display = EGL_NO_DISPLAY;
+    bool valid = false;
+    bool display_bound = false;
     QOffscreenSurface *offscreenSurface = nullptr;
     QOpenGLContext *localContext = nullptr;
 
-    PFNEGLBINDWAYLANDDISPLAYWL egl_bind_wayland_display;
-    PFNEGLUNBINDWAYLANDDISPLAYWL egl_unbind_wayland_display;
-    PFNEGLQUERYWAYLANDBUFFERWL_compat egl_query_wayland_buffer;
+    PFNEGLBINDWAYLANDDISPLAYWL egl_bind_wayland_display = nullptr;
+    PFNEGLUNBINDWAYLANDDISPLAYWL egl_unbind_wayland_display = nullptr;
+    PFNEGLQUERYWAYLANDBUFFERWL_compat egl_query_wayland_buffer = nullptr;
 
-    PFNEGLCREATEIMAGEKHRPROC egl_create_image;
-    PFNEGLDESTROYIMAGEKHRPROC egl_destroy_image;
+    PFNEGLCREATEIMAGEKHRPROC egl_create_image = nullptr;
+    PFNEGLDESTROYIMAGEKHRPROC egl_destroy_image = nullptr;
 
-    PFNGLEGLIMAGETARGETTEXTURE2DOESPROC gl_egl_image_target_texture_2d;
+    PFNGLEGLIMAGETARGETTEXTURE2DOESPROC gl_egl_image_target_texture_2d = nullptr;
 
-    QEGLStreamConvenience *funcs;
+    QEGLStreamConvenience *funcs = nullptr;
     static WaylandEglClientBufferIntegrationPrivate *get(WaylandEglClientBufferIntegration *integration) {
         return shuttingDown ? nullptr : integration->d_ptr.data();
     }
@@ -206,24 +206,7 @@ public:
 
 bool WaylandEglClientBufferIntegrationPrivate::shuttingDown = false;
 
-BufferState::BufferState()
-    : egl_format(EGL_TEXTURE_RGBA)
-    , egl_stream(EGL_NO_STREAM_KHR)
-    , isYInverted(true)
-    , eglMode(ModeUninitialized)
-{}
-
 WaylandEglClientBufferIntegrationPrivate::WaylandEglClientBufferIntegrationPrivate()
-    : egl_display(EGL_NO_DISPLAY)
-    , valid(false)
-    , display_bound(false)
-    , egl_bind_wayland_display(nullptr)
-    , egl_unbind_wayland_display(nullptr)
-    , egl_query_wayland_buffer(nullptr)
-    , egl_create_image(nullptr)
-    , egl_destroy_image(nullptr)
-    , gl_egl_image_target_texture_2d(nullptr)
-    , funcs(nullptr)
 {
 }
 
@@ -394,8 +377,7 @@ void WaylandEglClientBufferIntegrationPrivate::handleEglstreamTexture(WaylandEgl
 }
 
 WaylandEglClientBufferIntegration::WaylandEglClientBufferIntegration()
-    : QtWayland::ClientBufferIntegration()
-    , d_ptr(new WaylandEglClientBufferIntegrationPrivate)
+    : d_ptr(new WaylandEglClientBufferIntegrationPrivate)
 {
 }
 
diff --git a/src/hardwareintegration/compositor/xcomposite-egl/xcompositeeglintegration.cpp b/src/hardwareintegration/compositor/xcomposite-egl/xcompositeeglintegration.cpp
index 049b8b3fe..37932447c 100644
--- a/src/hardwareintegration/compositor/xcomposite-egl/xcompositeeglintegration.cpp
+++ b/src/hardwareintegration/compositor/xcomposite-egl/xcompositeeglintegration.cpp
@@ -68,8 +68,6 @@ QVector<EGLint> eglbuildSpec()
 }
 
 XCompositeEglClientBufferIntegration::XCompositeEglClientBufferIntegration()
-    : QtWayland::ClientBufferIntegration()
-    , mDisplay(nullptr)
 {
 
 }
@@ -100,7 +98,6 @@ QtWayland::ClientBuffer *XCompositeEglClientBufferIntegration::createBufferFor(w
 
 XCompositeEglClientBuffer::XCompositeEglClientBuffer(XCompositeEglClientBufferIntegration *integration, wl_resource *bufferResource)
     : QtWayland::ClientBuffer(bufferResource)
-    , m_texture(nullptr)
     , m_integration(integration)
 {
 }
diff --git a/src/hardwareintegration/compositor/xcomposite-egl/xcompositeeglintegration.h b/src/hardwareintegration/compositor/xcomposite-egl/xcompositeeglintegration.h
index 16d9591ba..f57f741c2 100644
--- a/src/hardwareintegration/compositor/xcomposite-egl/xcompositeeglintegration.h
+++ b/src/hardwareintegration/compositor/xcomposite-egl/xcompositeeglintegration.h
@@ -61,7 +61,7 @@ public:
     inline EGLDisplay eglDisplay() const { return mEglDisplay; }
 
 private:
-    Display *mDisplay;
+    Display *mDisplay = nullptr;
     EGLDisplay mEglDisplay;
 };
 
@@ -78,7 +78,7 @@ public:
     }
 
 private:
-    QOpenGLTexture *m_texture;
+    QOpenGLTexture *m_texture = nullptr;
     XCompositeEglClientBufferIntegration *m_integration;
 };
 
diff --git a/src/hardwareintegration/compositor/xcomposite-glx/xcompositeglxintegration.cpp b/src/hardwareintegration/compositor/xcomposite-glx/xcompositeglxintegration.cpp
index b1c947b53..511a8f6b8 100644
--- a/src/hardwareintegration/compositor/xcomposite-glx/xcompositeglxintegration.cpp
+++ b/src/hardwareintegration/compositor/xcomposite-glx/xcompositeglxintegration.cpp
@@ -71,9 +71,6 @@ QVector<int> qglx_buildSpec()
 
 
 XCompositeGLXClientBufferIntegration::XCompositeGLXClientBufferIntegration()
-    : QtWayland::ClientBufferIntegration()
-    , mDisplay(nullptr)
-    , mHandler(nullptr)
 {
     qDebug() << "Loading GLX integration";
 }
@@ -122,9 +119,7 @@ QtWayland::ClientBuffer *XCompositeGLXClientBufferIntegration::createBufferFor(w
 
 XCompositeGLXClientBuffer::XCompositeGLXClientBuffer(XCompositeGLXClientBufferIntegration *integration, wl_resource *bufferResource)
     : QtWayland::ClientBuffer(bufferResource)
-    , m_texture(nullptr)
     , m_integration(integration)
-    , m_glxPixmap(0)
 {
 }
 
diff --git a/src/hardwareintegration/compositor/xcomposite-glx/xcompositeglxintegration.h b/src/hardwareintegration/compositor/xcomposite-glx/xcompositeglxintegration.h
index ccdca7613..23b856e93 100644
--- a/src/hardwareintegration/compositor/xcomposite-glx/xcompositeglxintegration.h
+++ b/src/hardwareintegration/compositor/xcomposite-glx/xcompositeglxintegration.h
@@ -68,9 +68,9 @@ public:
     PFNGLXRELEASETEXIMAGEEXTPROC m_glxReleaseTexImageEXT;
 
 private:
-    Display *mDisplay;
+    Display *mDisplay = nullptr;
     int mScreen;
-    XCompositeHandler *mHandler;
+    XCompositeHandler *mHandler = nullptr;
 };
 
 class XCompositeGLXClientBuffer : public QtWayland::ClientBuffer
@@ -86,9 +86,9 @@ public:
     }
 
 private:
-    QOpenGLTexture *m_texture;
+    QOpenGLTexture *m_texture = nullptr;
     XCompositeGLXClientBufferIntegration *m_integration;
-    GLXPixmap m_glxPixmap;
+    GLXPixmap m_glxPixmap = 0;
 };
 
 QT_END_NAMESPACE
diff --git a/src/imports/compositor/qwaylandmousetracker.cpp b/src/imports/compositor/qwaylandmousetracker.cpp
index 99adef5bf..a39aa0bea 100644
--- a/src/imports/compositor/qwaylandmousetracker.cpp
+++ b/src/imports/compositor/qwaylandmousetracker.cpp
@@ -48,8 +48,6 @@ class QWaylandMouseTrackerPrivate : public QQuickItemPrivate
     Q_DECLARE_PUBLIC(QWaylandMouseTracker)
 public:
     QWaylandMouseTrackerPrivate()
-        : windowSystemCursorEnabled(false)
-        , hovered(false)
     {
         QImage cursorImage(64,64,QImage::Format_ARGB32);
         cursorImage.fill(Qt::transparent);
@@ -79,9 +77,9 @@ public:
     }
 
     QPointF mousePos;
-    bool windowSystemCursorEnabled;
+    bool windowSystemCursorEnabled = false;
     QPixmap cursorPixmap;
-    bool hovered;
+    bool hovered = false;
 };
 
 QWaylandMouseTracker::QWaylandMouseTracker(QQuickItem *parent)
diff --git a/src/plugins/decorations/bradient/main.cpp b/src/plugins/decorations/bradient/main.cpp
index ceb07c803..9a7e91e6f 100644
--- a/src/plugins/decorations/bradient/main.cpp
+++ b/src/plugins/decorations/bradient/main.cpp
@@ -153,14 +153,12 @@ private:
     QColor m_foregroundColor;
     QColor m_backgroundColor;
     QStaticText m_windowTitle;
-    Button m_clicking;
+    Button m_clicking = None;
 };
 
 
 
 QWaylandBradientDecoration::QWaylandBradientDecoration()
-    : QWaylandAbstractDecoration()
-    , m_clicking(None)
 {
     QPalette palette;
     m_foregroundColor = palette.color(QPalette::Active, QPalette::HighlightedText);
diff --git a/src/plugins/platforms/qwayland-egl/qwaylandeglplatformintegration.h b/src/plugins/platforms/qwayland-egl/qwaylandeglplatformintegration.h
index dde430381..625583913 100644
--- a/src/plugins/platforms/qwayland-egl/qwaylandeglplatformintegration.h
+++ b/src/plugins/platforms/qwayland-egl/qwaylandeglplatformintegration.h
@@ -52,8 +52,7 @@ class QWaylandEglPlatformIntegration : public QWaylandIntegration
 {
 public:
     QWaylandEglPlatformIntegration()
-        : QWaylandIntegration()
-        , m_client_buffer_integration(new QWaylandEglClientBufferIntegration())
+        : m_client_buffer_integration(new QWaylandEglClientBufferIntegration())
     {
         m_client_buffer_integration->initialize(display());
     }
diff --git a/src/plugins/platforms/qwayland-xcomposite-egl/qwaylandxcompositeeglplatformintegration.h b/src/plugins/platforms/qwayland-xcomposite-egl/qwaylandxcompositeeglplatformintegration.h
index 009a12f67..e711133c0 100644
--- a/src/plugins/platforms/qwayland-xcomposite-egl/qwaylandxcompositeeglplatformintegration.h
+++ b/src/plugins/platforms/qwayland-xcomposite-egl/qwaylandxcompositeeglplatformintegration.h
@@ -52,8 +52,7 @@ class QWaylandXCompositeEglPlatformIntegration : public QWaylandIntegration
 {
 public:
     QWaylandXCompositeEglPlatformIntegration()
-        : QWaylandIntegration()
-        , m_client_buffer_integration(new QWaylandXCompositeEGLClientBufferIntegration())
+        : m_client_buffer_integration(new QWaylandXCompositeEGLClientBufferIntegration())
     {
         m_client_buffer_integration->initialize(display());
     }
diff --git a/src/plugins/platforms/qwayland-xcomposite-glx/qwaylandxcompositeglxplatformintegration.h b/src/plugins/platforms/qwayland-xcomposite-glx/qwaylandxcompositeglxplatformintegration.h
index a8a70bdd9..32e286c52 100644
--- a/src/plugins/platforms/qwayland-xcomposite-glx/qwaylandxcompositeglxplatformintegration.h
+++ b/src/plugins/platforms/qwayland-xcomposite-glx/qwaylandxcompositeglxplatformintegration.h
@@ -53,8 +53,7 @@ class QWaylandXCompositeGlxPlatformIntegration : public QWaylandIntegration
 {
 public:
     QWaylandXCompositeGlxPlatformIntegration()
-        : QWaylandIntegration()
-        , m_client_buffer_integration(new QWaylandXCompositeGLXIntegration())
+        : m_client_buffer_integration(new QWaylandXCompositeGLXIntegration())
     {
         m_client_buffer_integration->initialize(display());
     }
diff --git a/src/plugins/shellintegration/ivi-shell/qwaylandivishellintegration.cpp b/src/plugins/shellintegration/ivi-shell/qwaylandivishellintegration.cpp
index fee812501..14074625a 100644
--- a/src/plugins/shellintegration/ivi-shell/qwaylandivishellintegration.cpp
+++ b/src/plugins/shellintegration/ivi-shell/qwaylandivishellintegration.cpp
@@ -55,12 +55,6 @@ QT_BEGIN_NAMESPACE
 namespace QtWaylandClient {
 
 QWaylandIviShellIntegration::QWaylandIviShellIntegration()
-    : m_iviApplication(nullptr)
-    , m_iviController(nullptr)
-    , m_lastSurfaceId(0)
-    , m_surfaceNumber(0)
-    , m_useEnvSurfaceId(false)
-    , m_mutex(QMutex::Recursive)
 {
 }
 
diff --git a/src/plugins/shellintegration/ivi-shell/qwaylandivishellintegration.h b/src/plugins/shellintegration/ivi-shell/qwaylandivishellintegration.h
index 745b3e487..0b575c6c8 100644
--- a/src/plugins/shellintegration/ivi-shell/qwaylandivishellintegration.h
+++ b/src/plugins/shellintegration/ivi-shell/qwaylandivishellintegration.h
@@ -68,12 +68,12 @@ private:
     uint32_t getNextUniqueSurfaceId();
 
 private:
-    QtWayland::ivi_application *m_iviApplication;
-    QtWayland::ivi_controller *m_iviController;
-    uint32_t m_lastSurfaceId;
-    uint32_t m_surfaceNumber;
-    bool m_useEnvSurfaceId;
-    QMutex m_mutex;
+    QtWayland::ivi_application *m_iviApplication = nullptr;
+    QtWayland::ivi_controller *m_iviController = nullptr;
+    uint32_t m_lastSurfaceId = 0;
+    uint32_t m_surfaceNumber = 0;
+    bool m_useEnvSurfaceId = false;
+    QMutex m_mutex{QMutex::Recursive};
 };
 
 }
diff --git a/src/plugins/shellintegration/ivi-shell/qwaylandivisurface.cpp b/src/plugins/shellintegration/ivi-shell/qwaylandivisurface.cpp
index 335aa852c..ec529b124 100644
--- a/src/plugins/shellintegration/ivi-shell/qwaylandivisurface.cpp
+++ b/src/plugins/shellintegration/ivi-shell/qwaylandivisurface.cpp
@@ -52,7 +52,6 @@ QWaylandIviSurface::QWaylandIviSurface(struct ::ivi_surface *ivi_surface, QWayla
     : QtWayland::ivi_surface(ivi_surface)
     , QWaylandShellSurface(window)
     , m_window(window)
-    , m_extendedWindow(nullptr)
 {
     createExtendedSurface(window);
 }
@@ -63,7 +62,6 @@ QWaylandIviSurface::QWaylandIviSurface(struct ::ivi_surface *ivi_surface, QWayla
     , QWaylandShellSurface(window)
     , QtWayland::ivi_controller_surface(iviControllerSurface)
     , m_window(window)
-    , m_extendedWindow(nullptr)
 {
     createExtendedSurface(window);
 }
diff --git a/src/plugins/shellintegration/ivi-shell/qwaylandivisurface_p.h b/src/plugins/shellintegration/ivi-shell/qwaylandivisurface_p.h
index 0a717b398..f24ecd37a 100644
--- a/src/plugins/shellintegration/ivi-shell/qwaylandivisurface_p.h
+++ b/src/plugins/shellintegration/ivi-shell/qwaylandivisurface_p.h
@@ -70,7 +70,7 @@ private:
     void ivi_controller_surface_visibility(int32_t visibility) override;
 
     QWaylandWindow *m_window;
-    QWaylandExtendedSurface *m_extendedWindow;
+    QWaylandExtendedSurface *m_extendedWindow = nullptr;
 };
 
 }
diff --git a/src/shared/qwaylandinputmethodeventbuilder.cpp b/src/shared/qwaylandinputmethodeventbuilder.cpp
index 6acf312ed..88056637d 100644
--- a/src/shared/qwaylandinputmethodeventbuilder.cpp
+++ b/src/shared/qwaylandinputmethodeventbuilder.cpp
@@ -50,16 +50,6 @@
 
 QT_BEGIN_NAMESPACE
 
-QWaylandInputMethodEventBuilder::QWaylandInputMethodEventBuilder()
-    : m_anchor(0)
-    , m_cursor(0)
-    , m_deleteBefore(0)
-    , m_deleteAfter(0)
-    , m_preeditCursor(0)
-    , m_preeditStyles()
-{
-}
-
 QWaylandInputMethodEventBuilder::~QWaylandInputMethodEventBuilder()
 {
 }
diff --git a/src/shared/qwaylandinputmethodeventbuilder_p.h b/src/shared/qwaylandinputmethodeventbuilder_p.h
index 3912afc04..a234cf44b 100644
--- a/src/shared/qwaylandinputmethodeventbuilder_p.h
+++ b/src/shared/qwaylandinputmethodeventbuilder_p.h
@@ -47,7 +47,7 @@ QT_BEGIN_NAMESPACE
 class QWaylandInputMethodEventBuilder
 {
 public:
-    QWaylandInputMethodEventBuilder();
+    QWaylandInputMethodEventBuilder() = default;
     ~QWaylandInputMethodEventBuilder();
 
     void reset();
@@ -66,12 +66,12 @@ public:
 private:
     QPair<int, int> replacementForDeleteSurrounding();
 
-    int32_t m_anchor;
-    int32_t m_cursor;
-    uint32_t m_deleteBefore;
-    uint32_t m_deleteAfter;
+    int32_t m_anchor = 0;
+    int32_t m_cursor = 0;
+    uint32_t m_deleteBefore = 0;
+    uint32_t m_deleteAfter = 0;
 
-    int32_t m_preeditCursor;
+    int32_t m_preeditCursor = 0;
     QList<QInputMethodEvent::Attribute> m_preeditStyles;
 };
 
diff --git a/tests/auto/client/client/tst_client.cpp b/tests/auto/client/client/tst_client.cpp
index eb99b2e2f..8ee52d736 100644
--- a/tests/auto/client/client/tst_client.cpp
+++ b/tests/auto/client/client/tst_client.cpp
@@ -48,14 +48,6 @@ class TestWindow : public QWindow
 {
 public:
     TestWindow()
-        : focusInEventCount(0)
-        , focusOutEventCount(0)
-        , keyPressEventCount(0)
-        , keyReleaseEventCount(0)
-        , mousePressEventCount(0)
-        , mouseReleaseEventCount(0)
-        , touchEventCount(0)
-        , keyCode(0)
     {
         setSurfaceType(QSurface::RasterSurface);
         setGeometry(0, 0, 32, 32);
@@ -103,15 +95,15 @@ public:
 
     QPoint frameOffset() const { return QPoint(frameMargins().left(), frameMargins().top()); }
 
-    int focusInEventCount;
-    int focusOutEventCount;
-    int keyPressEventCount;
-    int keyReleaseEventCount;
-    int mousePressEventCount;
-    int mouseReleaseEventCount;
-    int touchEventCount;
+    int focusInEventCount = 0;
+    int focusOutEventCount = 0;
+    int keyPressEventCount = 0;
+    int keyReleaseEventCount = 0;
+    int mousePressEventCount = 0;
+    int mouseReleaseEventCount = 0;
+    int touchEventCount = 0;
 
-    uint keyCode;
+    uint keyCode = 0;
     QPoint mousePressPos;
 };
 
@@ -404,7 +396,6 @@ class DndWindow : public QWindow
 public:
     DndWindow(QWindow *parent = nullptr)
         : QWindow(parent)
-        , dragStarted(false)
     {
         QImage cursorImage(64,64,QImage::Format_ARGB32);
         cursorImage.fill(Qt::blue);
@@ -412,7 +403,7 @@ public:
     }
     ~DndWindow(){}
     QPoint frameOffset() const { return QPoint(frameMargins().left(), frameMargins().top()); }
-    bool dragStarted;
+    bool dragStarted = false;
 
 protected:
     void mousePressEvent(QMouseEvent *event) override
diff --git a/tests/auto/client/shared/mockcompositor.cpp b/tests/auto/client/shared/mockcompositor.cpp
index 2f1d68b01..1d76cec12 100644
--- a/tests/auto/client/shared/mockcompositor.cpp
+++ b/tests/auto/client/shared/mockcompositor.cpp
@@ -37,9 +37,6 @@
 
 #include <stdio.h>
 MockCompositor::MockCompositor()
-    : m_alive(true)
-    , m_ready(false)
-    , m_compositor(0)
 {
     pthread_create(&m_thread, 0, run, this);
 
diff --git a/tests/auto/client/shared/mockcompositor.h b/tests/auto/client/shared/mockcompositor.h
index 747da38fa..c6de12376 100644
--- a/tests/auto/client/shared/mockcompositor.h
+++ b/tests/auto/client/shared/mockcompositor.h
@@ -212,13 +212,13 @@ private:
 
     static void *run(void *data);
 
-    bool m_alive;
-    bool m_ready;
+    bool m_alive = true;
+    bool m_ready = false;
     pthread_t m_thread;
     QMutex m_mutex;
     QWaitCondition m_waitCondition;
 
-    Impl::Compositor *m_compositor;
+    Impl::Compositor *m_compositor = nullptr;
 
     QList<Command> m_commandQueue;
 };
diff --git a/tests/auto/client/shared/mockinput.cpp b/tests/auto/client/shared/mockinput.cpp
index 9cea85b6d..8b7592824 100644
--- a/tests/auto/client/shared/mockinput.cpp
+++ b/tests/auto/client/shared/mockinput.cpp
@@ -232,10 +232,7 @@ void Seat::seat_get_touch(Resource *resource, uint32_t id)
 }
 
 Keyboard::Keyboard(Compositor *compositor)
-    : wl_keyboard()
-    , m_compositor(compositor)
-    , m_focusResource(nullptr)
-    , m_focus(nullptr)
+    : m_compositor(compositor)
 {
 }
 
@@ -286,10 +283,7 @@ void Keyboard::keyboard_destroy_resource(wl_keyboard::Resource *resource)
 }
 
 Pointer::Pointer(Compositor *compositor)
-    : wl_pointer()
-    , m_compositor(compositor)
-    , m_focusResource(nullptr)
-    , m_focus(nullptr)
+    : m_compositor(compositor)
 {
 }
 
@@ -393,10 +387,7 @@ DataOffer::DataOffer()
 }
 
 DataDevice::DataDevice(Compositor *compositor)
-    : wl_data_device()
-    , m_compositor(compositor)
-    , m_dataOffer(nullptr)
-    , m_focus(nullptr)
+    : m_compositor(compositor)
 {
 
 }
diff --git a/tests/auto/client/shared/mockinput.h b/tests/auto/client/shared/mockinput.h
index 9c217b6ac..5760ab40c 100644
--- a/tests/auto/client/shared/mockinput.h
+++ b/tests/auto/client/shared/mockinput.h
@@ -85,8 +85,8 @@ protected:
 private:
     Compositor *m_compositor;
 
-    Resource *m_focusResource;
-    Surface *m_focus;
+    Resource *m_focusResource = nullptr;
+    Surface *m_focus = nullptr;
 };
 
 class Pointer : public QtWaylandServer::wl_pointer
@@ -108,8 +108,8 @@ protected:
 private:
     Compositor *m_compositor;
 
-    Resource *m_focusResource;
-    Surface *m_focus;
+    Resource *m_focusResource = nullptr;
+    Surface *m_focus = nullptr;
 };
 
 class Touch : public QtWaylandServer::wl_touch
@@ -146,8 +146,8 @@ protected:
 
 private:
     Compositor *m_compositor;
-    QtWaylandServer::wl_data_offer *m_dataOffer;
-    Surface* m_focus;
+    QtWaylandServer::wl_data_offer *m_dataOffer = nullptr;
+    Surface* m_focus = nullptr;
 };
 
 class DataDeviceManager : public QtWaylandServer::wl_data_device_manager
diff --git a/tests/auto/client/shared/mocksurface.cpp b/tests/auto/client/shared/mocksurface.cpp
index 7aa2a00b2..98a9615a6 100644
--- a/tests/auto/client/shared/mocksurface.cpp
+++ b/tests/auto/client/shared/mocksurface.cpp
@@ -62,10 +62,8 @@ void Compositor::sendSurfaceLeave(void *data, const QList<QVariant> &parameters)
 
 Surface::Surface(wl_client *client, uint32_t id, int v, Compositor *compositor)
     : QtWaylandServer::wl_surface(client, id, v)
-    , m_buffer(nullptr)
     , m_compositor(compositor)
     , m_mockSurface(new MockSurface(this))
-    , m_mapped(false)
 {
 }
 
diff --git a/tests/auto/client/shared/mocksurface.h b/tests/auto/client/shared/mocksurface.h
index 5155599bb..8bf6eb755 100644
--- a/tests/auto/client/shared/mocksurface.h
+++ b/tests/auto/client/shared/mocksurface.h
@@ -63,12 +63,12 @@ protected:
                        uint32_t callback) override;
     void surface_commit(Resource *resource) override;
 private:
-    wl_resource *m_buffer;
+    wl_resource *m_buffer = nullptr;
 
     Compositor *m_compositor;
     QSharedPointer<MockSurface> m_mockSurface;
     QList<wl_resource *> m_frameCallbackList;
-    bool m_mapped;
+    bool m_mapped = false;
 };
 
 }
diff --git a/tests/auto/compositor/compositor/mockclient.cpp b/tests/auto/compositor/compositor/mockclient.cpp
index 4720b0d9f..e6eac1553 100644
--- a/tests/auto/compositor/compositor/mockclient.cpp
+++ b/tests/auto/compositor/compositor/mockclient.cpp
@@ -47,14 +47,6 @@ const struct wl_registry_listener MockClient::registryListener = {
 
 MockClient::MockClient()
     : display(wl_display_connect("wayland-qt-test-0"))
-    , compositor(nullptr)
-    , registry(nullptr)
-    , wlshell(nullptr)
-    , xdgShell(nullptr)
-    , iviApplication(nullptr)
-    , refreshRate(-1)
-    , error(0 /* means no error according to spec */)
-    , protocolError({0, 0, nullptr})
 {
     if (!display)
         qFatal("MockClient(): wl_display_connect() failed");
@@ -223,7 +215,6 @@ ivi_surface *MockClient::createIviSurface(wl_surface *surface, uint iviId)
 }
 
 ShmBuffer::ShmBuffer(const QSize &size, wl_shm *shm)
-    : handle(nullptr)
 {
     int stride = size.width() * 4;
     int alloc = stride * size.height();
diff --git a/tests/auto/compositor/compositor/mockclient.h b/tests/auto/compositor/compositor/mockclient.h
index dd50f9a28..8933f8327 100644
--- a/tests/auto/compositor/compositor/mockclient.h
+++ b/tests/auto/compositor/compositor/mockclient.h
@@ -44,7 +44,7 @@ public:
     ShmBuffer(const QSize &size, wl_shm *shm);
     ~ShmBuffer();
 
-    struct wl_buffer *handle;
+    struct wl_buffer *handle = nullptr;
     struct wl_shm_pool *shm_pool;
     QImage image;
 };
@@ -63,29 +63,29 @@ public:
     ivi_surface *createIviSurface(wl_surface *surface, uint iviId);
 
     wl_display *display;
-    wl_compositor *compositor;
+    wl_compositor *compositor = nullptr;
     QMap<uint, wl_output *> m_outputs;
     wl_shm *shm;
-    wl_registry *registry;
-    wl_shell *wlshell;
-    xdg_shell *xdgShell;
-    ivi_application *iviApplication;
+    wl_registry *registry = nullptr;
+    wl_shell *wlshell = nullptr;
+    xdg_shell *xdgShell = nullptr;
+    ivi_application *iviApplication = nullptr;
 
     QList<MockSeat *> m_seats;
 
     QRect geometry;
     QSize resolution;
-    int refreshRate;
+    int refreshRate = -1;
     QWaylandOutputMode currentMode;
     QWaylandOutputMode preferredMode;
     QList<QWaylandOutputMode> modes;
 
     int fd;
-    int error;
+    int error = 0 /* means no error according to spec */;
     struct {
-        uint id;
-        uint code;
-        const wl_interface *interface;
+        uint id = 0;
+        uint code = 0;
+        const wl_interface *interface = nullptr;
     } protocolError;
 
 private slots:
diff --git a/tests/auto/compositor/compositor/testcompositor.cpp b/tests/auto/compositor/compositor/testcompositor.cpp
index f91d0d3f1..710bb7b3a 100644
--- a/tests/auto/compositor/compositor/testcompositor.cpp
+++ b/tests/auto/compositor/compositor/testcompositor.cpp
@@ -33,8 +33,7 @@
 #include <wayland-server.h>
 
 TestCompositor::TestCompositor(bool createInputDev)
-    : QWaylandCompositor()
-    , shell(new QWaylandWlShell(this))
+    : shell(new QWaylandWlShell(this))
     , m_createSeat(createInputDev)
 {
     setSocketName("wayland-qt-test-0");