diff --git a/gtk/gtkmagnifier.c b/gtk/gtkmagnifier.c
index 755f01e8bb..e7ab74b9cf 100644
--- a/gtk/gtkmagnifier.c
+++ b/gtk/gtkmagnifier.c
@@ -186,7 +186,7 @@ _gtk_magnifier_set_inspected (GtkMagnifier *magnifier,
 {
   GtkMagnifierPrivate *priv;
 
-  g_return_val_if_fail (GTK_IS_MAGNIFIER (magnifier), NULL);
+  g_return_if_fail (GTK_IS_MAGNIFIER (magnifier));
 
   priv = _gtk_magnifier_get_instance_private (magnifier);