//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// <string>

// template<class charT, class traits, class Allocator>
//   basic_string<charT,traits,Allocator>
//   operator+(const basic_string<charT,traits,Allocator>& lhs,
//             const basic_string<charT,traits,Allocator>& rhs);

// template<class charT, class traits, class Allocator>
//   basic_string<charT,traits,Allocator>&&
//   operator+(const basic_string<charT,traits,Allocator>&& lhs,
//             const basic_string<charT,traits,Allocator>& rhs);

// template<class charT, class traits, class Allocator>
//   basic_string<charT,traits,Allocator>&&
//   operator+(const basic_string<charT,traits,Allocator>& lhs,
//             const basic_string<charT,traits,Allocator>&& rhs);

// template<class charT, class traits, class Allocator>
//   basic_string<charT,traits,Allocator>&&
//   operator+(const basic_string<charT,traits,Allocator>&& lhs,
//             const basic_string<charT,traits,Allocator>&& rhs);

#include <string>
#include <cassert>

template <class S>
void
test0(const S& lhs, const S& rhs, const S& x)
{
    assert(lhs + rhs == x);
}

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

template <class S>
void
test1(S&& lhs, const S& rhs, const S& x)
{
    assert(move(lhs) + rhs == x);
}

template <class S>
void
test2(const S& lhs, S&& rhs, const S& x)
{
    assert(lhs + move(rhs) == x);
}

template <class S>
void
test3(S&& lhs, S&& rhs, const S& x)
{
    assert(move(lhs) + move(rhs) == x);
}

#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES

typedef std::string S;

int main()
{
    test0(S(""), S(""), S(""));
    test0(S(""), S("12345"), S("12345"));
    test0(S(""), S("1234567890"), S("1234567890"));
    test0(S(""), S("12345678901234567890"), S("12345678901234567890"));
    test0(S("abcde"), S(""), S("abcde"));
    test0(S("abcde"), S("12345"), S("abcde12345"));
    test0(S("abcde"), S("1234567890"), S("abcde1234567890"));
    test0(S("abcde"), S("12345678901234567890"), S("abcde12345678901234567890"));
    test0(S("abcdefghij"), S(""), S("abcdefghij"));
    test0(S("abcdefghij"), S("12345"), S("abcdefghij12345"));
    test0(S("abcdefghij"), S("1234567890"), S("abcdefghij1234567890"));
    test0(S("abcdefghij"), S("12345678901234567890"), S("abcdefghij12345678901234567890"));
    test0(S("abcdefghijklmnopqrst"), S(""), S("abcdefghijklmnopqrst"));
    test0(S("abcdefghijklmnopqrst"), S("12345"), S("abcdefghijklmnopqrst12345"));
    test0(S("abcdefghijklmnopqrst"), S("1234567890"), S("abcdefghijklmnopqrst1234567890"));
    test0(S("abcdefghijklmnopqrst"), S("12345678901234567890"), S("abcdefghijklmnopqrst12345678901234567890"));

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

    test1(S(""), S(""), S(""));
    test1(S(""), S("12345"), S("12345"));
    test1(S(""), S("1234567890"), S("1234567890"));
    test1(S(""), S("12345678901234567890"), S("12345678901234567890"));
    test1(S("abcde"), S(""), S("abcde"));
    test1(S("abcde"), S("12345"), S("abcde12345"));
    test1(S("abcde"), S("1234567890"), S("abcde1234567890"));
    test1(S("abcde"), S("12345678901234567890"), S("abcde12345678901234567890"));
    test1(S("abcdefghij"), S(""), S("abcdefghij"));
    test1(S("abcdefghij"), S("12345"), S("abcdefghij12345"));
    test1(S("abcdefghij"), S("1234567890"), S("abcdefghij1234567890"));
    test1(S("abcdefghij"), S("12345678901234567890"), S("abcdefghij12345678901234567890"));
    test1(S("abcdefghijklmnopqrst"), S(""), S("abcdefghijklmnopqrst"));
    test1(S("abcdefghijklmnopqrst"), S("12345"), S("abcdefghijklmnopqrst12345"));
    test1(S("abcdefghijklmnopqrst"), S("1234567890"), S("abcdefghijklmnopqrst1234567890"));
    test1(S("abcdefghijklmnopqrst"), S("12345678901234567890"), S("abcdefghijklmnopqrst12345678901234567890"));

    test2(S(""), S(""), S(""));
    test2(S(""), S("12345"), S("12345"));
    test2(S(""), S("1234567890"), S("1234567890"));
    test2(S(""), S("12345678901234567890"), S("12345678901234567890"));
    test2(S("abcde"), S(""), S("abcde"));
    test2(S("abcde"), S("12345"), S("abcde12345"));
    test2(S("abcde"), S("1234567890"), S("abcde1234567890"));
    test2(S("abcde"), S("12345678901234567890"), S("abcde12345678901234567890"));
    test2(S("abcdefghij"), S(""), S("abcdefghij"));
    test2(S("abcdefghij"), S("12345"), S("abcdefghij12345"));
    test2(S("abcdefghij"), S("1234567890"), S("abcdefghij1234567890"));
    test2(S("abcdefghij"), S("12345678901234567890"), S("abcdefghij12345678901234567890"));
    test2(S("abcdefghijklmnopqrst"), S(""), S("abcdefghijklmnopqrst"));
    test2(S("abcdefghijklmnopqrst"), S("12345"), S("abcdefghijklmnopqrst12345"));
    test2(S("abcdefghijklmnopqrst"), S("1234567890"), S("abcdefghijklmnopqrst1234567890"));
    test2(S("abcdefghijklmnopqrst"), S("12345678901234567890"), S("abcdefghijklmnopqrst12345678901234567890"));

    test3(S(""), S(""), S(""));
    test3(S(""), S("12345"), S("12345"));
    test3(S(""), S("1234567890"), S("1234567890"));
    test3(S(""), S("12345678901234567890"), S("12345678901234567890"));
    test3(S("abcde"), S(""), S("abcde"));
    test3(S("abcde"), S("12345"), S("abcde12345"));
    test3(S("abcde"), S("1234567890"), S("abcde1234567890"));
    test3(S("abcde"), S("12345678901234567890"), S("abcde12345678901234567890"));
    test3(S("abcdefghij"), S(""), S("abcdefghij"));
    test3(S("abcdefghij"), S("12345"), S("abcdefghij12345"));
    test3(S("abcdefghij"), S("1234567890"), S("abcdefghij1234567890"));
    test3(S("abcdefghij"), S("12345678901234567890"), S("abcdefghij12345678901234567890"));
    test3(S("abcdefghijklmnopqrst"), S(""), S("abcdefghijklmnopqrst"));
    test3(S("abcdefghijklmnopqrst"), S("12345"), S("abcdefghijklmnopqrst12345"));
    test3(S("abcdefghijklmnopqrst"), S("1234567890"), S("abcdefghijklmnopqrst1234567890"));
    test3(S("abcdefghijklmnopqrst"), S("12345678901234567890"), S("abcdefghijklmnopqrst12345678901234567890"));

#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
}