From @grondilu

This is perl6 version 2013.04-43-g5ad46fd built on parrot 5.2.0 revision RELEASE_5_2_0

my Bag $bag .= new​: <foo foo bar>;
for $bag.keys X $bag.keys -> $a, $b {
  say $a, $b;
}

No output, no error. The program never enters the for loop. It should.

From @usev6

This works now (on Moar, Parrot and JVM)​:

$ perl6 -e 'my Bag $bag .= new​: <foo foo bar>; for $bag.keys X $bag.keys -> $a, $b { say $a, $b }'
foofoo
foobar
barfoo
barbar

I added a test to S02-types/bag.t with the following commit​: Raku/roast@245c5988e7

@usev6 - Status changed from 'new' to 'resolved'