package foo:root;

interface ai {}
interface bi {}

world a {
    import ai;
    import bi;
}

world b {
    include foo:bar/bar-a;
}

world c {
    include b;
    include foo:bar/bar-a;
}

world union-world {
    include a;
    include b;
    include c;
    include foo:bar/bar-a;
    include foo:baz/baz-a;
}