震惊！c++17程序居然是这么写的！

struct NonMovable
{
    NonMovable() noexcept = default;
    NonMovable(NonMovable&&) noexcept = delete;
    NonMovable& operator=(NonMovable&&) noexcept = delete;
};

NonMovable Make()
{
    return NonMovable{};
}

int main()
{
    [[maybe_unused]] const auto x = Make();
    [[maybe_unused]] const auto z = NonMovable{};
    [[maybe_unused]] const auto y = NonMovable{NonMovable{}};
}