diff --git a/gdk/wayland/gdkpopup-wayland-private.h b/gdk/wayland/gdkpopup-wayland-private.h
index 4055aa4943..396e841aef 100644
--- a/gdk/wayland/gdkpopup-wayland-private.h
+++ b/gdk/wayland/gdkpopup-wayland-private.h
@@ -18,13 +18,6 @@
 #pragma once
 
 
-void update_popup_layout_state (GdkWaylandPopup *wayland_popup,
-                                int              x,
-                                int              y,
-                                int              width,
-                                int              height,
-                                GdkPopupLayout  *layout);
-
 void gdk_wayland_surface_configure_popup          (GdkWaylandPopup *popup);
 void frame_callback_popup                         (GdkWaylandPopup *popup);
 void gdk_wayland_popup_hide_surface               (GdkWaylandPopup *popup);
diff --git a/gdk/wayland/gdkpopup-wayland.c b/gdk/wayland/gdkpopup-wayland.c
index 139204791e..378a82a641 100644
--- a/gdk/wayland/gdkpopup-wayland.c
+++ b/gdk/wayland/gdkpopup-wayland.c
@@ -48,6 +48,13 @@
 #include "gdksurface-wayland-private.h"
 #include "gdkpopup-wayland-private.h"
 
+static void update_popup_layout_state (GdkWaylandPopup *wayland_popup,
+                                       int              x,
+                                       int              y,
+                                       int              width,
+                                       int              height,
+                                       GdkPopupLayout  *layout);
+
 /* {{{ Utilities */
 
 static gboolean
@@ -644,7 +651,7 @@ calculate_popup_rect (GdkWaylandPopup *wayland_popup,
   };
 }
 
-void
+static void
 update_popup_layout_state (GdkWaylandPopup *wayland_popup,
                            int              x,
                            int              y,