Hi Mattias,

Thanks for noticing this!

> If you want the regexp to match a list of one or more symbols, what about this:
>
>   (rx "("
>       (* whitespace)
>       (regexp ert-font-lock--face-symbol-re)
>       (* (+ whitespace)
>          (regexp ert-font-lock--face-symbol-re))
>       ")")
>

Got it, thanks. I forgot about relint! Regex performance is easy to
get wrong. I'd really like peg.el to be merged and used for this kind
of parsing.

Anyway, can you please take a look at the patch? It fixes the problem
noticed by relint as well as a couple of other minor things, and adds
tests to make sure regexes work the way I want them to.

Thank you
Vlad


-- 
Regards,

Vladimir Kazanov