libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair.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
//
//===----------------------------------------------------------------------===//

// UNSUPPORTED: c++03

// <utility>

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

// pair& operator=(pair const& p);

#include <utility>
#include <memory>
#include <cassert>

#include "test_macros.h"
#include "archetypes.h"

struct CountAssign {
  int copied = 0;
  int moved = 0;
  TEST_CONSTEXPR_CXX20 CountAssign() = default;
  TEST_CONSTEXPR_CXX20 CountAssign& operator=(CountAssign const&) {
    ++copied;
    return *this;
  }
  TEST_CONSTEXPR_CXX20 CountAssign& operator=(CountAssign&&) {
    ++moved;
    return *this;
  }
};

struct Incomplete;
extern Incomplete inc_obj;

TEST_CONSTEXPR_CXX20 bool test() {
  {
    typedef std::pair<ConstexprTestTypes::CopyOnly, int> P;
    const P p1(ConstexprTestTypes::CopyOnly(), short{4});
    P p2;
    p2 = p1;
    assert(p2.second == 4);
  }
  {
    using P = std::pair<int&, int&&>;
    int x = 42;
    int y = 101;
    int x2 = -1;
    int y2 = 300;
    P p1(x, std::move(y));
    P p2(x2, std::move(y2));
    p1 = p2;
    assert(p1.first == x2);
    assert(p1.second == y2);
  }
  {
    using P = std::pair<int, ConstexprTestTypes::NonCopyable>;
    static_assert(!std::is_copy_assignable<P>::value, "");
  }
  {
    using P = std::pair<CountAssign, ConstexprTestTypes::Copyable>;
    static_assert(std::is_copy_assignable<P>::value, "");
    P p;
    P p2;
    p = p2;
    assert(p.first.copied == 1);
    assert(p.first.moved == 0);
    assert(p2.first.copied == 0);
    assert(p2.first.moved == 0);
  }
  {
    using P = std::pair<int, ConstexprTestTypes::MoveAssignOnly>;
    static_assert(!std::is_copy_assignable<P>::value, "");
  }
  {
    using P = std::pair<int, std::unique_ptr<int> >;
    static_assert(!std::is_copy_assignable<P>::value, "");
  }
  {
    using P = std::pair<int, Incomplete&>;
    static_assert(!std::is_copy_assignable<P>::value, "");
    P p(42, inc_obj);
    assert(&p.second == &inc_obj);
  }

  return true;
}

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

  return 0;
}

struct Incomplete {};
Incomplete inc_obj;