diff --git a/src/indent.c b/src/indent.c
index ed7ce97..89653c7 100644
--- a/src/indent.c
+++ b/src/indent.c
@@ -2098,6 +2098,9 @@
 {
     linenr_T	lnum;
 
+    if (in_vim9script() && check_for_lnum_arg(argvars, 0) == FAIL)
+	return;
+
     lnum = tv_get_lnum(argvars);
     if (lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count)
 	rettv->vval.v_number = get_indent_lnum(lnum);
@@ -2115,6 +2118,9 @@
     pos_T	pos;
     linenr_T	lnum;
 
+    if (in_vim9script() && check_for_lnum_arg(argvars, 0) == FAIL)
+	return;
+
     pos = curwin->w_cursor;
     lnum = tv_get_lnum(argvars);
     if (lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count)