diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index ace5b5c093..19bf77a2dc 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -4506,7 +4506,7 @@ static int get_tabpage_arg(exarg_T *eap)
     } else {
       tab_number = eap->line2;
       if (!unaccept_arg0 && *skipwhite(*eap->cmdlinep) == '-') {
-        --tab_number;
+        tab_number--;
         if (tab_number < unaccept_arg0) {
           eap->errmsg = e_invarg;
         }