As mentioned earlier this didn't segfault on Moar for a while. Even though the code still segfaults on Parrot most of the time, I had difficulties to reproduce the segfault in a test file. Therefore I regard this ticket as resolved without having a test in roast.
WRT the flapping segfault on Parrot: Since support for Parrot was suspended with Rakudo Star Release 2015.02, I'm going to close this ticket. I'll add the ticket to a list of closed ticket living in the mu repository: https://github.com/perl6/mu/blob/master/misc/rt.perl.org/tickets_closed_parrot_only.txt. In case support for Parrot will be restored in some future release the listed tickets can be checked and re-opened as appropriate.