Just to be complete here is a second backtrace with a similar error (if it
needs to be fixed at multiple places):
```
Panic: file index-search-result.c: line 174
(index_search_result_update_appends): assertion failed:
(result->search_args->args == &search_arg)
Error: Raw backtrace: /usr/lib/dov
Originally posted and debugged here:
https://github.com/slusarz/dovecot-fts-flatcurve/issues/66
I have to following panic with fts flatcurve enabled:
```
Panic: file index-search-result.c: line 132 (index_search_result_update_flags):
assertion failed: (result->search_args->args == &search_arg)
