patch 8.2.3916: no error for passing an invalid line number to append() Commit: https://github.com/vim/vim/commit/8dac2acd6a79d571ff5409d9c90b4c9e73237eb4 Author: Bram Moolenaar <Bram@vim.org> Date: Mon Dec 27 20:57:06 2021 +0000 patch 8.2.3916: no error for passing an invalid line number to append() Problem: No error for passing an invalid line number to append(). Solution: In Vim9 script check for a non-negative number. (closes https://github.com/vim/vim/issues/9417)

/* drawline.c */
int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, int nochange, int number_only);
/* vim: set ft=c : */