patch 8.2.1397: Vim9: return type of maparg() not adjusted for fourth arg Commit: https://github.com/vim/vim/commit/4a6d1b660fcea67931202527ad2852da55d26d49 Author: Bram Moolenaar <Bram@vim.org> Date: Sat Aug 8 17:55:49 2020 +0200 patch 8.2.1397: Vim9: return type of maparg() not adjusted for fourth arg Problem: Vim9: return type of maparg() not adjusted for fourth argument. Solution: Check if fourth argument is present. (closes https://github.com/vim/vim/issues/6645)