#include <cassert>
#include <type_traits>

struct Empty {};
struct Identity {
    int operator()(int value) const { return value; }
};
struct ViaBase : Empty {
    int value = 3;
};
struct WithPolicy {
    [[no_unique_address]] Identity policy;
    int value = 7;
    int evaluate() const { return policy(value); }
};
struct TwoTags {
    [[no_unique_address]] Empty first;
    [[no_unique_address]] Empty second;
    int value = 1;
};

int main() {
    static_assert(std::is_empty_v<Empty>);
    static_assert(sizeof(Empty) >= 1);
    Empty array[2];
    assert(&array[0] != &array[1]);
    ViaBase inherited;
    WithPolicy composed;
    TwoTags tags;
    assert(inherited.value == 3);
    assert(composed.evaluate() == 7);
    assert(&tags.first != &tags.second);
}