// A flat-imported module authoring its OWN `Box { a }`, a DISTINCT nominal from
// main's `Box { m }`. The four route-all surfaces in `main` must each bind main's
// own `Box`; the disjoint field sets make a wrong binding a hard compile error.
Box :: struct { a: s32; }

dep_box :: () -> s32 {
    b : Box = ---;
    b.a = 99;
    return b.a;
}