// Namespace B authors a generic `Box($T)` with `make`. It wins the global
// last-wins `struct_template_map`, so the qualified head `a.Box(..)` must NOT
// silently resolve to this when namespace `a` lacks `Box`.
Box :: struct($T: Type) {
    x: T;

    make :: (value: T) -> Box(T) {
        .{ x = value }
    }
}