diff --git a/src/evalfunc.c b/src/evalfunc.c
index 6d845c1..f83559d 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -2521,6 +2521,8 @@
     static void
 f_char2nr(typval_T *argvars, typval_T *rettv)
 {
+    if (in_vim9script() && check_for_string_arg(argvars, 0) == FAIL)
+	return;
     if (has_mbyte)
     {
 	int	utf8 = 0;
@@ -2685,11 +2687,16 @@
     char_u	*typestr;
     int		error = FALSE;
 
+    if (in_vim9script() && check_for_string_arg(argvars, 0) == FAIL)
+	return;
+
     message = tv_get_string_chk(&argvars[0]);
     if (message == NULL)
 	error = TRUE;
     if (argvars[1].v_type != VAR_UNKNOWN)
     {
+	if (in_vim9script() && check_for_string_arg(argvars, 1) == FAIL)
+	    return;
 	buttons = tv_get_string_buf_chk(&argvars[1], buf);
 	if (buttons == NULL)
 	    error = TRUE;
@@ -2698,6 +2705,8 @@
 	    def = (int)tv_get_number_chk(&argvars[2], &error);
 	    if (argvars[3].v_type != VAR_UNKNOWN)
 	    {
+		if (in_vim9script() && check_for_string_arg(argvars, 3) == FAIL)
+		    return;
 		typestr = tv_get_string_buf_chk(&argvars[3], buf2);
 		if (typestr == NULL)
 		    error = TRUE;