diff --git a/src/quickfix.c b/src/quickfix.c
index 39424ca..eb1a4a8 100644
--- a/src/quickfix.c
+++ b/src/quickfix.c
@@ -8466,6 +8466,14 @@
 
     rettv->vval.v_number = -1;
 
+    if (in_vim9script()
+	    && (check_for_number_arg(argvars, 0) == FAIL
+		|| check_for_list_arg(argvars, 1) == FAIL
+		|| check_for_opt_string_arg(argvars, 2) == FAIL
+		|| (argvars[2].v_type != VAR_UNKNOWN
+		    && check_for_opt_dict_arg(argvars, 3) == FAIL)))
+	return;
+
     win = find_win_by_nr_or_id(&argvars[0]);
     if (win != NULL)
 	set_qf_ll_list(win, &argvars[1], &argvars[2], &argvars[3], rettv);
@@ -8477,6 +8485,13 @@
     void
 f_setqflist(typval_T *argvars, typval_T *rettv)
 {
+    if (in_vim9script()
+	    && (check_for_list_arg(argvars, 0) == FAIL
+		|| check_for_opt_string_arg(argvars, 1) == FAIL
+		|| (argvars[1].v_type != VAR_UNKNOWN
+		    && check_for_opt_dict_arg(argvars, 2) == FAIL)))
+	return;
+
     set_qf_ll_list(NULL, &argvars[0], &argvars[1], &argvars[2], rettv);
 }
 #endif