third_party/llvm-project/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.pass.cpp

//===----------------------------------------------------------------------===//
//
//                     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.
//
//===----------------------------------------------------------------------===//

// <utility>

// template <class T1, class T2> struct pair

// tuple_element<I, pair<T1, T2> >::type

#include <utility>

template <class T1, class T2>
void test()
{
    {
    typedef T1 Exp1;
    typedef T2 Exp2;
    typedef std::pair<T1, T2> P;
    static_assert((std::is_same<typename std::tuple_element<0, P>::type, Exp1>::value), "");
    static_assert((std::is_same<typename std::tuple_element<1, P>::type, Exp2>::value), "");
    }
    {
    typedef T1 const Exp1;
    typedef T2 const Exp2;
    typedef std::pair<T1, T2> const P;
    static_assert((std::is_same<typename std::tuple_element<0, P>::type, Exp1>::value), "");
    static_assert((std::is_same<typename std::tuple_element<1, P>::type, Exp2>::value), "");
    }
    {
    typedef T1 volatile Exp1;
    typedef T2 volatile Exp2;
    typedef std::pair<T1, T2> volatile P;
    static_assert((std::is_same<typename std::tuple_element<0, P>::type, Exp1>::value), "");
    static_assert((std::is_same<typename std::tuple_element<1, P>::type, Exp2>::value), "");
    }
    {
    typedef T1 const volatile Exp1;
    typedef T2 const volatile Exp2;
    typedef std::pair<T1, T2> const volatile P;
    static_assert((std::is_same<typename std::tuple_element<0, P>::type, Exp1>::value), "");
    static_assert((std::is_same<typename std::tuple_element<1, P>::type, Exp2>::value), "");
    }
}

int main()
{
    test<int, short>();
    test<int*, char>();
}