[perl #73608] [BUG] Rakudo (nqp-rx) regexes won't backtrack properly into capturing parentheses

[Carl Mäsak]

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<masak> rakudo: say "aaaab" ~~ /a*b/; say "aaaab" ~~ /.*b/; say
"aaaab" ~~ /(a*)b/; say "aaaab" ~~ /(.*)b/
<p6eval> rakudo e3937f: OUTPUT«aaaab␤aaaab␤aaaab␤␤»
* masak submits rakudobug
<masak> oh, and bug courtesy of jnthn++

Just to be extra clear, all four of the above should print 'aaaab'
(followed by a newline), but the combination of a backtracking
construct such as quantifier:sym<*> and capturing parens doesn't work.

And it's not specific for the quantifiers, either. This should print 'ab':

<masak> rakudo: say "ab" ~~ / (ab|a) b /
<p6eval> rakudo e3937f: OUTPUT«␤»

So there's something wrong with backtracking and capturing in general.

This is really a bug in nqp-rx, but I'm submitting it as a rakudobug.