- res = mime_which_token_aux(s, len);
- return res ? res->val : MUTT_MIME_TOKEN_UNKNOWN;
+ if (len) {
+ const struct tok *res = mime_which_token_aux(s, len);
+ return res ? res->val : MUTT_MIME_TOKEN_UNKNOWN;
+ } else {
+ return MUTT_MIME_TOKEN_UNKNOWN;
+ }