diff --git a/gtk/gtkplacessidebar.c b/gtk/gtkplacessidebar.c
index 28d305aad3..e6dfbc22be 100644
--- a/gtk/gtkplacessidebar.c
+++ b/gtk/gtkplacessidebar.c
@@ -4347,7 +4347,7 @@ gtk_places_sidebar_class_init (GtkPlacesSidebarClass *class)
                         G_SIGNAL_RUN_FIRST,
                         G_STRUCT_OFFSET (GtkPlacesSidebarClass, mount),
                         NULL, NULL,
-                        _gtk_marshal_VOID__VOID,
+                        _gtk_marshal_VOID__OBJECT,
                         G_TYPE_NONE,
                         1,
                         G_TYPE_MOUNT_OPERATION);
@@ -4369,7 +4369,7 @@ gtk_places_sidebar_class_init (GtkPlacesSidebarClass *class)
                         G_SIGNAL_RUN_FIRST,
                         G_STRUCT_OFFSET (GtkPlacesSidebarClass, unmount),
                         NULL, NULL,
-                        _gtk_marshal_VOID__VOID,
+                        _gtk_marshal_VOID__OBJECT,
                         G_TYPE_NONE,
                         1,
                         G_TYPE_MOUNT_OPERATION);