1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20 10 11 // E& error() & noexcept; 12 // const E& error() const & noexcept; 13 // E&& error() && noexcept; 14 // const E&& error() const && noexcept; 15 16 #include <cassert> 17 #include <concepts> 18 #include <expected> 19 #include <utility> 20 21 template <class T> 22 concept ErrorNoexcept = 23 requires(T&& t) { 24 { std::forward<T>(t).error() } noexcept; 25 }; 26 27 static_assert(!ErrorNoexcept<int>); 28 static_assert(ErrorNoexcept<std::bad_expected_access<int>&>); 29 static_assert(ErrorNoexcept<std::bad_expected_access<int> const&>); 30 static_assert(ErrorNoexcept<std::bad_expected_access<int>&&>); 31 static_assert(ErrorNoexcept<std::bad_expected_access<int> const&&>); 32 33 void test() { 34 // & 35 { 36 std::bad_expected_access<int> e(5); 37 decltype(auto) i = e.error(); 38 static_assert(std::same_as<decltype(i), int&>); 39 assert(i == 5); 40 } 41 42 // const & 43 { 44 const std::bad_expected_access<int> e(5); 45 decltype(auto) i = e.error(); 46 static_assert(std::same_as<decltype(i), const int&>); 47 assert(i == 5); 48 } 49 50 // && 51 { 52 std::bad_expected_access<int> e(5); 53 decltype(auto) i = std::move(e).error(); 54 static_assert(std::same_as<decltype(i), int&&>); 55 assert(i == 5); 56 } 57 58 // const && 59 { 60 const std::bad_expected_access<int> e(5); 61 decltype(auto) i = std::move(e).error(); 62 static_assert(std::same_as<decltype(i), const int&&>); 63 assert(i == 5); 64 } 65 } 66 67 int main(int, char**) { 68 test(); 69 return 0; 70 } 71