parse_subsignature() gets confused about empty parens [issue #17689]

I've been using the `parse_subsignature()` that I added back in 5.31.3
and discovered it doesn't actually work properly for the trivial empty
signature

  sub func () { ... }

My investigation has led me to a weird corner of the parser where it
appears to consume an extra character in this situation that it doesn't
anytime else.

  https://github.com/Perl/perl5/issues/17689#issuecomment-607971392

At this point I'm kindof stuck. Does anyone else have any ideas on what
to look at?

-- 
Paul "LeoNerd" Evans

leonerd@leonerd.org.uk      |  https://metacpan.org/author/PEVANS
http://www.leonerd.org.uk/  |  https://www.tindie.com/stores/leonerd/

• parse_subsignature() gets confused about empty parens [issue #17689] by Paul "LeoNerd" Evans