llvm/libcxx/test/libcxx/ranges/range.adaptors/range.move.wrap/deref.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, c++11, c++14, c++17

// T& <copyable-box>::operator*()
// T const& <copyable-box>::operator*() const

#include <ranges>

#include <cassert>
#include <type_traits>
#include <utility> // in_place_t

#include "types.h"

template <class T>
constexpr void check() {
  // non-const version
  {
    std::ranges::__movable_box<T> x(std::in_place, 10);
    T& result = *x;
    static_assert(noexcept(*x));
    assert(result.value == 10);
  }

  // const version
  {
    std::ranges::__movable_box<T> const x(std::in_place, 10);
    T const& result = *x;
    static_assert(noexcept(*x));
    assert(result.value == 10);
  }
}

constexpr bool test() {
  check<CopyConstructible>();        // primary template
  check<Copyable>();                 // optimization #1
  check<NothrowCopyConstructible>(); // optimization #2
  return true;
}

int main(int, char**) {
  assert(test());
  static_assert(test());
  return 0;
}