Potential Rakudobug

linked-list.p6

role LL[::T] {
    has T $.item;
    has LL[T] $.next;
    method visit(&c) {
        c($.item);
        $.next.visit(&c)  if $.next;
    }
}

my $t = LL[Int].new(
    item => 5,
    next => LL[Int].new( item => 4 ),
);
say $t.perl;
$t.visit(&say);