patch 8.2.1773: crash when calling mapset() with a list as first argument Commit: https://github.com/vim/vim/commit/1b9129809d8269acb8e7c79d8fc99c7976b4f76e Author: Bram Moolenaar <Bram@vim.org> Date: Tue Sep 29 21:45:41 2020 +0200 patch 8.2.1773: crash when calling mapset() with a list as first argument Problem: Crash when calling mapset() with a list as first argument. Solution: Check for NULL. (closes https://github.com/vim/vim/issues/7040)

--- a/src/map.c
+++ b/src/map.c
@@ -2304,6 +2304,8 @@ f_mapset(typval_T *argvars, typval_T *re
     char_u	*arg;
 
     which = tv_get_string_buf_chk(&argvars[0], buf);
+    if (which == NULL)
+	return;
     mode = get_map_mode(&which, 0);
     is_abbr = (int)tv_get_number(&argvars[1]);