From @masak

Rakudo r33613 treats the :x($n) adverb as "up to $n matches", not (as
specced) "exactly $n matches".

$ perl6 -e 'say "foofoofoo".subst("foo", "bar", :x(3))' # right
barbarbar

$ perl6 -e 'say "foofoofoo".subst("foo", "bar", :x(4))' # wrong
barbarbar

From @jnthn

On Tue Dec 09 02​:00​:40 2008, masak wrote​:

Rakudo r33613 treats the :x($n) adverb as "up to $n matches", not (as
specced) "exactly $n matches".

$ perl6 -e 'say "foofoofoo".subst("foo", "bar", :x(3))' # right
barbarbar

$ perl6 -e 'say "foofoofoo".subst("foo", "bar", :x(4))' # wrong
barbarbar

Fixed (plus for the regex case) in git 01811bf. Note the spec says it
hands back the original string rather than any kind of more epic fail,
so far as I can tell. Unfudged a couple of tests in subst.t too.

Thanks,

Jonathan

The RT System itself - Status changed from 'new' to 'open'

@jnthn - Status changed from 'open' to 'resolved'