diff --git a/gobject/gobject.c b/gobject/gobject.c
index 762bb9221..bb468384c 100644
--- a/gobject/gobject.c
+++ b/gobject/gobject.c
@@ -745,8 +745,9 @@ g_object_interface_install_property (gpointer      g_iface,
   GTypeInterface *iface_class = g_iface;
 	
   g_return_if_fail (G_TYPE_IS_INTERFACE (iface_class->g_type));
-  g_return_if_fail (G_IS_PARAM_SPEC (pspec));
   g_return_if_fail (!G_IS_PARAM_SPEC_OVERRIDE (pspec)); /* paranoid */
+
+  g_return_if_fail (G_IS_PARAM_SPEC (pspec));
   g_return_if_fail (PARAM_SPEC_PARAM_ID (pspec) == 0);	/* paranoid */
 
   g_return_if_fail (pspec->flags & (G_PARAM_READABLE | G_PARAM_WRITABLE));