diff --git a/src/backends/drm/egl_gbm_layer.cpp b/src/backends/drm/egl_gbm_layer.cpp
index 45b4a838ae..a992ae15bd 100644
--- a/src/backends/drm/egl_gbm_layer.cpp
+++ b/src/backends/drm/egl_gbm_layer.cpp
@@ -133,7 +133,7 @@ bool EglGbmLayer::endRendering(const QRegion &damagedRegion)
         m_currentBuffer = buffer;
         m_currentDamage = damagedRegion;
     }
-    return buffer;
+    return !buffer.isNull();
 }
 
 QRegion EglGbmLayer::currentDamage() const
diff --git a/src/backends/wayland/wayland_backend.cpp b/src/backends/wayland/wayland_backend.cpp
index d0ddc05250..55e1e1a169 100644
--- a/src/backends/wayland/wayland_backend.cpp
+++ b/src/backends/wayland/wayland_backend.cpp
@@ -387,12 +387,12 @@ void WaylandInputDevice::setLeds(LEDs leds)
 
 bool WaylandInputDevice::isKeyboard() const
 {
-    return m_keyboard;
+    return !m_keyboard.isNull();
 }
 
 bool WaylandInputDevice::isAlphaNumericKeyboard() const
 {
-    return m_keyboard;
+    return !m_keyboard.isNull();
 }
 
 bool WaylandInputDevice::isPointer() const
@@ -407,7 +407,7 @@ bool WaylandInputDevice::isTouchpad() const
 
 bool WaylandInputDevice::isTouch() const
 {
-    return m_touch;
+    return !m_touch.isNull();
 }
 
 bool WaylandInputDevice::isTabletTool() const
diff --git a/src/effects/screenshot/screenshotdbusinterface1.cpp b/src/effects/screenshot/screenshotdbusinterface1.cpp
index 7d00156bcd..74464f6dce 100644
--- a/src/effects/screenshot/screenshotdbusinterface1.cpp
+++ b/src/effects/screenshot/screenshotdbusinterface1.cpp
@@ -783,7 +783,7 @@ QString ScreenShotDBusInterface1::screenshotArea(int x, int y, int width, int he
 
 bool ScreenShotDBusInterface1::isTakingScreenshot() const
 {
-    return m_source;
+    return !m_source.isNull();
 }
 
 void ScreenShotDBusInterface1::showInfoMessage(InfoMessageMode mode)
diff --git a/src/libkwineffects/kwinoffscreenquickview.cpp b/src/libkwineffects/kwinoffscreenquickview.cpp
index aeb6269c32..a6526f2ed6 100644
--- a/src/libkwineffects/kwinoffscreenquickview.cpp
+++ b/src/libkwineffects/kwinoffscreenquickview.cpp
@@ -237,7 +237,7 @@ void OffscreenQuickView::update()
         return;
     }
 
-    bool usingGl = d->m_glcontext;
+    bool usingGl = !d->m_glcontext.isNull();
 
     if (usingGl) {
         if (!d->m_glcontext->makeCurrent(d->m_offscreenSurface.data())) {
diff --git a/src/platformsupport/scenes/opengl/openglsurfacetexture.cpp b/src/platformsupport/scenes/opengl/openglsurfacetexture.cpp
index 8a950ce17f..07a71ec576 100644
--- a/src/platformsupport/scenes/opengl/openglsurfacetexture.cpp
+++ b/src/platformsupport/scenes/opengl/openglsurfacetexture.cpp
@@ -21,7 +21,7 @@ OpenGLSurfaceTexture::~OpenGLSurfaceTexture()
 
 bool OpenGLSurfaceTexture::isValid() const
 {
-    return m_texture;
+    return !m_texture.isNull();
 }
 
 OpenGLBackend *OpenGLSurfaceTexture::backend() const
diff --git a/src/plugins/screencast/screencaststream.cpp b/src/plugins/screencast/screencaststream.cpp
index bb095867aa..531decc1ec 100644
--- a/src/plugins/screencast/screencaststream.cpp
+++ b/src/plugins/screencast/screencaststream.cpp
@@ -284,7 +284,7 @@ bool ScreenCastStream::createStream()
     int n_params;
 
     auto canCreateDmaBuf = [this] () -> bool {
-        return QSharedPointer<DmaBufTexture>(kwinApp()->platform()->createDmaBufTexture(m_resolution));
+        return !QSharedPointer<DmaBufTexture>(kwinApp()->platform()->createDmaBufTexture(m_resolution)).isNull();
     };
     const auto format = m_source->hasAlphaChannel() ? SPA_VIDEO_FORMAT_BGRA : SPA_VIDEO_FORMAT_BGR;