third_party/boost/variant/test/hash_recursive_variant_test.cpp

// Copyright (c) 2016
// Mikhail Maximov
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

#include "boost/config.hpp"
#include "boost/core/lightweight_test.hpp"

#if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES) && !defined(BOOST_NO_CXX11_HDR_UNORDERED_SET)
// Test is based on reported issues:
// https://svn.boost.org/trac/boost/ticket/12508
// https://svn.boost.org/trac/boost/ticket/12645
// Following hash function was not found at compile time,
// because boost::variant construction from boost::recursive_variant_
// was forbidden.

#include <unordered_set>

#include "boost/variant.hpp"

struct hash;

using int_t = int;

template <typename T>
using basic_set_t = std::unordered_set<T, hash>;

using value_t = boost::make_recursive_variant<
		int_t,
		basic_set_t<boost::recursive_variant_>
>::type;

using set_t = basic_set_t<value_t>;

struct hash
{
    size_t operator()(const value_t&) const
    {
      return 0;
    }
};

void run()
{
    set_t s;
    int_t i = 3;
    value_t v = i;
    auto emplace_result = s.emplace(v); // raises error above
    BOOST_TEST(emplace_result.second);
    v = s;
    const set_t& check_set = boost::get<set_t>(v);
    BOOST_TEST(!check_set.empty());
    for (const auto& check_v : check_set) {
      BOOST_TEST(s.find(check_v) != s.end());
    }
    for (const auto& check_v : s) {
      BOOST_TEST(check_set.find(check_v) != check_set.end());
    }
}

#else // !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES) && !defined(BOOST_NO_CXX11_HDR_UNORDERED_SET)
// if no unordered_set and template aliases - does nothing
void run() {}
#endif

int main()
{
   run();
   return boost::report_errors();
}