{

optional<std::string&> opt;

opt = make_optional_string_ref();

BOOST_TEST(bool(opt));

BOOST_TEST(*opt == global);

BOOST_TEST(boost::addressof(*opt) == boost::addressof(global));

{

std::string& str = *make_optional_string_ref();

BOOST_TEST(str == global);

BOOST_TEST(boost::addressof(str) == boost::addressof(global));

}

{

std::string& str = make_optional_string_ref().value();

BOOST_TEST(str == global);

BOOST_TEST(boost::addressof(str) == boost::addressof(global));

}

{

std::string& str = make_optional_string_ref().value_or(global);

BOOST_TEST(str == global);

BOOST_TEST(boost::addressof(str) == boost::addressof(global));

}

{

std::string& str = make_optional_string_ref().value_or_eval(&return_global);

BOOST_TEST(str == global);

BOOST_TEST(boost::addressof(str) == boost::addressof(global));

}

return boost::report_errors();