patch 8.2.1773: crash when calling mapset() with a list as first argumentv8.2.1773

Problem:    Crash when calling mapset() with a list as first argument.
Solution:   Check for NULL. (closes #7040)

1 files changed, 2 insertions, 0 deletions

diff --git a/src/map.c b/src/map.c
index eed3a55d04..6a994d4185 100644
--- a/src/map.c
+++ b/src/map.c
@@ -2304,6 +2304,8 @@ f_mapset(typval_T *argvars, typval_T *rettv UNUSED)
     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]);