libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_const_pair_U_V.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <utility>

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

// template<class U, class V> pair& operator=(const pair<U, V>& p);

#include <utility>
#include <cassert>

#include "test_macros.h"
#if TEST_STD_VER >= 11
#include "archetypes.h"
#endif

struct CopyAssignableInt {
  CopyAssignableInt& operator=(int&) { return *this; }
};

struct Unrelated {};

TEST_CONSTEXPR_CXX20 bool test() {
  {
    typedef std::pair<int, short> P1;
    typedef std::pair<double, long> P2;
    P1 p1(3, static_cast<short>(4));
    P2 p2;
    p2 = p1;
    assert(p2.first == 3);
    assert(p2.second == 4);
  }
#if TEST_STD_VER >= 20
  {
    using C = ConstexprTestTypes::TestType;
    using P = std::pair<int, C>;
    using T = std::pair<long, C>;
    const T t(42, -42);
    P p(101, 101);
    p = t;
    assert(p.first == 42);
    assert(p.second.value == -42);
  }
#elif TEST_STD_VER >= 11
  {
    using C = TestTypes::TestType;
    using P = std::pair<int, C>;
    using T = std::pair<long, C>;
    const T t(42, -42);
    P p(101, 101);
    C::reset_constructors();
    p = t;
    assert(C::constructed == 0);
    assert(C::assigned == 1);
    assert(C::copy_assigned == 1);
    assert(C::move_assigned == 0);
    assert(p.first == 42);
    assert(p.second.value == -42);
  }
  { // test const requirement
    using T = std::pair<CopyAssignableInt, CopyAssignableInt>;
    using P = std::pair<int, int>;
    static_assert(!std::is_assignable<T&, P const>::value, "");
  }
  {
    using T = std::pair<int, Unrelated>;
    using P = std::pair<Unrelated, int>;
    static_assert(!std::is_assignable<T&, P&>::value, "");
    static_assert(!std::is_assignable<P&, T&>::value, "");
  }
#endif
  return true;
}

int main(int, char**) {
  test();
#if TEST_STD_VER >= 20
  static_assert(test());
#endif

  return 0;
}