You can clone with
No one assigned
The selector div, li:matches([0-9,]+) causes a java.util.regex.PatternSyntaxException because QueryParser (line 63) thinks that the comma inside the regex is a combinator and thus extracts , li:matches([0-9 as the second alternative.
Instead of scanning ahead with `chompTo(","), the parser needs to parse its way through the alternative until it reaches a comma or the end of a string. That way, commata in regular expressions will be correctly interpreted as part of the regex.
Note that there may be many more variations of this bug in the parser. Wherever a construct allows embedding an arbitrary string one should expect this problem. [attr=a,b] for example is likely to cause the same issue. In a way, any invocation of chompTo() needs to examined.
I currently work around this by escaping the comma in the regex as in div, li:matches([0-9\\x2C]+).
Fixed parsing of group-or commas in CSS selectors.
Thanks for pointing this out! Fixed now.