| // -*- C++ -*- |
| //===----------------------------------------------------------------------===// |
| // |
| // 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 |
| // REQUIRES: c++experimental |
| |
| // <experimental/memory> |
| |
| // observer_ptr |
| // |
| // template <class W2> |
| // constexpr observer_ptr(observer_ptr<W2> other) noexcept; |
| |
| #include <experimental/memory> |
| #include <type_traits> |
| #include <cassert> |
| |
| #include "test_macros.h" |
| |
| template <class To, class From> |
| constexpr void test_converting_ctor() { |
| using ToPtr = std::experimental::observer_ptr<To>; |
| using FromPtr = std::experimental::observer_ptr<From>; |
| From obj; |
| FromPtr from(&obj); |
| ToPtr to = from; |
| |
| assert(from.get() == &obj); |
| assert(to.get() == &obj); |
| #if TEST_STD_VER >= 20 |
| static_assert(std::is_nothrow_convertible<FromPtr, ToPtr>::value); |
| #endif |
| } |
| |
| template <class To, class From> |
| constexpr void check_non_constructible() { |
| using ToPtr = std::experimental::observer_ptr<To>; |
| using FromPtr = std::experimental::observer_ptr<From>; |
| static_assert(!std::is_constructible<ToPtr, FromPtr>::value); |
| } |
| |
| struct Bar {}; |
| struct Base {}; |
| struct Derived : Base {}; |
| |
| constexpr bool test() { |
| test_converting_ctor<void, Bar>(); |
| test_converting_ctor<void, int>(); |
| test_converting_ctor<Base, Derived>(); |
| |
| check_non_constructible<Derived, Base>(); |
| check_non_constructible<int, void>(); |
| check_non_constructible<Bar, void>(); |
| check_non_constructible<int, long>(); |
| check_non_constructible<long, int>(); |
| |
| // Check const-ness |
| check_non_constructible<Bar, Bar const>(); |
| test_converting_ctor<Bar const, Bar>(); |
| |
| return true; |
| } |
| |
| int main(int, char**) { |
| test(); |
| static_assert(test()); |
| |
| return 0; |
| } |