A.pm6

module A {}
use nqp;

sub EXPORT {
    if $*W {
        my $block := { nqp::print(nqp::getlexdyn('$*W') ?? "world is still there!" !! "The world went away"); };
        $*W.add_object($block);
        my $op := $*W.add_phaser(Mu, 'CHECK', $block, class :: { method cuid { (^2**128).pick }});
    }
    Map.new
}

B.pm6

unit class B;
use A;