// A flat-imported module authors its OWN `Pair { a }`. The importing file (`main`)
// ALSO authors a `Pair` — its own author must win there (own-wins), while this
// module's `Pair` stays a DISTINCT nominal type used by `dep_pair`. The field sets
// are disjoint, so a cross-binding to the wrong `Pair` is a hard compile error.
Pair :: union { a: s32; }
dep_pair :: () -> s32 {
    p : Pair = ---;
    p.a = 9;
    return p.a;
}