diff --git a/src/server/xdgshell_interface.h b/src/server/xdgshell_interface.h
--- a/src/server/xdgshell_interface.h
+++ b/src/server/xdgshell_interface.h
@@ -478,5 +478,6 @@
 Q_DECLARE_METATYPE(KWayland::Server::XdgShellPopupInterface *)
 Q_DECLARE_METATYPE(KWayland::Server::XdgShellSurfaceInterface::State)
 Q_DECLARE_METATYPE(KWayland::Server::XdgShellSurfaceInterface::States)
+Q_DECLARE_OPERATORS_FOR_FLAGS(KWayland::Server::PositionerConstraints)
 
 #endif