diff --git a/src/window.c b/src/window.c
index bed3d3f..4946a3a 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1363,7 +1363,7 @@
 }
 
     static int
-win_valid_popup(win_T *win)
+win_valid_popup(win_T *win UNUSED)
 {
 #ifdef FEAT_TEXT_PROP
     win_T	*wp;