I agree with Mouq and after adding a test to S03-operators/misc.t with commit https://github.com/perl6/roast/commit/1e08ea21cc I'm now closing the ticket.
[perl #117045] [BUG] Guillemet form of subscript parses as infix hyperop in Rakudo
Christian Bartolomaeus via RT Wed, 15 Oct 2014 00:27:07 -0700
