diff --git a/autotests/integration/effects/slidingpopups_test.cpp b/autotests/integration/effects/slidingpopups_test.cpp
--- a/autotests/integration/effects/slidingpopups_test.cpp
+++ b/autotests/integration/effects/slidingpopups_test.cpp
@@ -18,6 +18,7 @@
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #include "kwin_wayland_test.h"
+#include "client.h"
 #include "composite.h"
 #include "effects.h"
 #include "effectloader.h"
diff --git a/autotests/integration/effects/translucency_test.cpp b/autotests/integration/effects/translucency_test.cpp
--- a/autotests/integration/effects/translucency_test.cpp
+++ b/autotests/integration/effects/translucency_test.cpp
@@ -18,6 +18,7 @@
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #include "kwin_wayland_test.h"
+#include "client.h"
 #include "composite.h"
 #include "effects.h"
 #include "effectloader.h"
diff --git a/autotests/integration/effects/wobbly_shade_test.cpp b/autotests/integration/effects/wobbly_shade_test.cpp
--- a/autotests/integration/effects/wobbly_shade_test.cpp
+++ b/autotests/integration/effects/wobbly_shade_test.cpp
@@ -18,6 +18,7 @@
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #include "kwin_wayland_test.h"
+#include "client.h"
 #include "composite.h"
 #include "cursor.h"
 #include "effects.h"
diff --git a/autotests/integration/move_resize_window_test.cpp b/autotests/integration/move_resize_window_test.cpp
--- a/autotests/integration/move_resize_window_test.cpp
+++ b/autotests/integration/move_resize_window_test.cpp
@@ -22,6 +22,7 @@
 #include "atoms.h"
 #include "platform.h"
 #include "abstract_client.h"
+#include "client.h"
 #include "cursor.h"
 #include "effects.h"
 #include "screens.h"
diff --git a/autotests/integration/x11_client_test.cpp b/autotests/integration/x11_client_test.cpp
--- a/autotests/integration/x11_client_test.cpp
+++ b/autotests/integration/x11_client_test.cpp
@@ -19,6 +19,7 @@
 *********************************************************************/
 #include "kwin_wayland_test.h"
 #include "atoms.h"
+#include "client.h"
 #include "composite.h"
 #include "effects.h"
 #include "effectloader.h"
diff --git a/effects.h b/effects.h
--- a/effects.h
+++ b/effects.h
@@ -24,12 +24,13 @@
 
 #include "kwineffects.h"
 
-#include "client.h"
 #include "scene.h"
 
 #include <QHash>
 #include <Plasma/FrameSvg>
 
+#include <memory>
+
 namespace Plasma {
 class Theme;
 }
@@ -53,10 +54,12 @@
 class DesktopThumbnailItem;
 class WindowThumbnailItem;
 
+class AbstractClient;
 class Client;
 class Compositor;
 class Deleted;
 class EffectLoader;
+class Toplevel;
 class Unmanaged;
 class WindowPropertyNotifyX11Filter;
 
diff --git a/effects/blur/blur.cpp b/effects/blur/blur.cpp
--- a/effects/blur/blur.cpp
+++ b/effects/blur/blur.cpp
@@ -20,11 +20,11 @@
  */
 
 #include "blur.h"
-#include "effects.h"
 #include "blurshader.h"
 // KConfigSkeleton
 #include "blurconfig.h"
 
+#include <QGuiApplication>
 #include <QMatrix4x4>
 #include <QLinkedList>
 #include <QScreen> // for QGuiApplication
diff --git a/pointer_input.cpp b/pointer_input.cpp
--- a/pointer_input.cpp
+++ b/pointer_input.cpp
@@ -19,6 +19,7 @@
 *********************************************************************/
 #include "pointer_input.h"
 #include "platform.h"
+#include "client.h"
 #include "effects.h"
 #include "input_event.h"
 #include "input_event_spy.h"
diff --git a/window_property_notify_x11_filter.cpp b/window_property_notify_x11_filter.cpp
--- a/window_property_notify_x11_filter.cpp
+++ b/window_property_notify_x11_filter.cpp
@@ -18,6 +18,7 @@
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #include "window_property_notify_x11_filter.h"
+#include "client.h"
 #include "effects.h"
 #include "unmanaged.h"
 #include "workspace.h"