diff --git a/gio/gtask.c b/gio/gtask.c
index 3540e6553..2b4720de8 100644
--- a/gio/gtask.c
+++ b/gio/gtask.c
@@ -2162,7 +2162,9 @@ GSourceFuncs trivial_source_funcs = {
   NULL, /* prepare */
   NULL, /* check */
   trivial_source_dispatch,
-  NULL
+  NULL, /* finalize */
+  NULL, /* closure */
+  NULL  /* marshal */
 };
 
 static void