llvm-project/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.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

// <optional>

// template <class U>
//   constexpr EXPLICIT optional(U&& u);

#include <cassert>
#include <optional>
#include <type_traits>

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

#include "../optional_helper_types.h"

using std::optional;

struct ImplicitThrow {
  constexpr ImplicitThrow(int x) {
    if (x != -1)
      TEST_THROW(6);
  }
};

struct ExplicitThrow {
  constexpr explicit ExplicitThrow(int x) {
    if (x != -1)
      TEST_THROW(6);
  }
};

struct ImplicitAny {
  template <class U>
  constexpr ImplicitAny(U&&) {}
};

template <class To, class From>
constexpr bool implicit_conversion(optional<To>&& opt, const From& v) {
  using O = optional<To>;
  static_assert(test_convertible<O, From>(), "");
  static_assert(!test_convertible<O, void*>(), "");
  static_assert(!test_convertible<O, From, int>(), "");
  return opt && *opt == static_cast<To>(v);
}

template <class To, class Input, class Expect>
constexpr bool explicit_conversion(Input&& in, const Expect& v) {
  using O = optional<To>;
  static_assert(std::is_constructible<O, Input>::value, "");
  static_assert(!std::is_convertible<Input, O>::value, "");
  static_assert(!std::is_constructible<O, void*>::value, "");
  static_assert(!std::is_constructible<O, Input, int>::value, "");
  optional<To> opt(std::forward<Input>(in));
  optional<To> opt2{std::forward<Input>(in)};
  return opt && *opt == static_cast<To>(v) && (opt2 && *opt2 == static_cast<To>(v));
}

void test_implicit() {
  {
    static_assert(implicit_conversion<long long>(42, 42), "");
  }
  {
    static_assert(implicit_conversion<long double>(3.14, 3.14), "");
  }
  {
    int x = 42;
    optional<void* const> o(&x);
    assert(*o == &x);
  }
  {
    using T = TrivialTestTypes::TestType;
    static_assert(implicit_conversion<T>(42, 42), "");
  }
  {
    using T = TestTypes::TestType;
    assert(implicit_conversion<T>(3, T(3)));
  }
  {
    using T = TestTypes::TestType;
    optional<T> opt({3});
    assert(opt && *opt == static_cast<T>(3));
  }
  {
    using O = optional<ImplicitAny>;
    static_assert(!test_convertible<O, std::in_place_t>(), "");
    static_assert(!test_convertible<O, std::in_place_t&>(), "");
    static_assert(!test_convertible<O, const std::in_place_t&>(), "");
    static_assert(!test_convertible<O, std::in_place_t&&>(), "");
    static_assert(!test_convertible<O, const std::in_place_t&&>(), "");
  }
#ifndef TEST_HAS_NO_EXCEPTIONS
  {
    try {
      using T       = ImplicitThrow;
      optional<T> t = 42;
      assert(false);
      ((void)t);
    } catch (int) {
    }
  }
#endif
}

void test_explicit() {
  {
    using T = ExplicitTrivialTestTypes::TestType;
    static_assert(explicit_conversion<T>(42, 42), "");
  }
  {
    using T = ExplicitConstexprTestTypes::TestType;
    static_assert(explicit_conversion<T>(42, 42), "");
    static_assert(!std::is_convertible<int, T>::value, "");
  }
  {
    using T = ExplicitTestTypes::TestType;
    T::reset();
    {
      assert(explicit_conversion<T>(42, 42));
      assert(T::alive == 0);
    }
    T::reset();
    {
      optional<T> t(42);
      assert(T::alive == 1);
      assert(T::value_constructed == 1);
      assert(T::move_constructed == 0);
      assert(T::copy_constructed == 0);
      assert(t.value().value == 42);
    }
    assert(T::alive == 0);
  }
#ifndef TEST_HAS_NO_EXCEPTIONS
  {
    try {
      using T = ExplicitThrow;
      optional<T> t(42);
      assert(false);
    } catch (int) {
    }
  }
#endif
}

#if TEST_STD_VER >= 26
constexpr bool test_ref() {
  {
    int i = 0;
    std::optional<int&> o(i);
    ASSERT_NOEXCEPT(std::optional<int&>(i));
    assert(o.has_value());
    assert(&(*o) == &i);
    assert(*o == 0);
    assert(o.value() == 0);
  }

  {
    ReferenceConversion<int> t{1, 2};
    ASSERT_NOEXCEPT(std::optional<int&>(t));
    std::optional<int&> o(t);
    assert(o.has_value());
    assert(&(*o) == &t.lvalue);
    assert(*o == 1);
  }

  {
    ReferenceConversion<int> t{1, 2};
    ASSERT_NOEXCEPT(std::optional<int&>(std::move(t)));
    std::optional<int&> o(std::move(t));
    assert(o.has_value());
    assert(&(*o) == &t.rvalue);
    assert(*o == 2);
  }

#  ifndef TEST_HAS_NO_EXCEPTIONS
  {
    ReferenceConversionThrows<int> t{1, 2, false};
    ASSERT_NOT_NOEXCEPT(std::optional<int&>(t));
    try {
      std::optional<int&> o(t);
      assert(o.has_value());
      assert(&(*o) == &t.lvalue);
      assert(*o == 1);
    } catch (int) {
      assert(false);
    }
  }
  {
    ReferenceConversionThrows<int> t{1, 2, false};
    ASSERT_NOT_NOEXCEPT(std::optional<int&>(std::move(t)));
    try {
      std::optional<int&> o(std::move(t));
      assert(o.has_value());
      assert(&(*o) == &t.rvalue);
      assert(*o == 2);
    } catch (int) {
      assert(false);
    }
  }
#  endif
  return true;
}
#endif

int main(int, char**) {
  test_implicit();
  test_explicit();
#if TEST_STD_VER >= 26
  assert(test_ref());
  static_assert(test_ref());
#endif
  return 0;
}