diff --git a/src/popupwin.c b/src/popupwin.c
index bb889d5..dd87705 100644
--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -2983,7 +2983,7 @@
     win_T	*wp;
     tabpage_T	*tp;
 
-    if (rettv_list_alloc(rettv) != OK)
+    if (rettv_list_alloc(rettv) == FAIL)
 	return;
     FOR_ALL_POPUPWINS(wp)
 	list_append_number(rettv->vval.v_list, wp->w_id);