[perl #123511] Parametric role used a second time will use old default values (MoarVM only)

[Christian Bartolomaeus via RT]

This works now with rakudo.moar (on 'nom' and 'glr'):

$ perl6-m -e 'role A [ :$a = 1, :$b = $a * 2] { method foo { say "$a $b" } }; 
role B does A[:a(1)] { }; role C does A[:a(2)] { }; B.new.foo; C.new.foo;'
1 2
2 4

I added a test to S14-roles/parameterized-mixin.t with commit 
https://github.com/perl6/roast/commit/6e925d7898.

I'm closing this ticket as 'resolved'.