Visitor Pattern package relationships in Perl 6

visitor-circular-dependencies.pm6

# this is a .gist to explain my solution wrt https://rt.perl.org/Public/Bug/Display.html?id=128275

# VisitorRoles.pm6

role Visitor {
  method visit {...}
}
role Node {
  method accept {...}
}

# MyNode.pm6
use VisitorRoles;

class MyNode does Node {
    has $.payload = "Perl6";
    method accept(Visitor:D $b) {
      $b.visit(self);
    }
}

# MyVisitor.pm6
use VisitorRoles;

class MyVisitor does Visitor {
    method visit(Node:D $a) {
        $a.payload;
    }
}