| //===----------------------------------------------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is dual licensed under the MIT and the University of Illinois Open |
| // Source Licenses. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // <optional> |
| // UNSUPPORTED: c++98, c++03, c++11, c++14 |
| // UNSUPPORTED: clang-5, apple-clang-9 |
| // UNSUPPORTED: libcpp-no-deduction-guides |
| // Clang 5 will generate bad implicit deduction guides |
| // Specifically, for the copy constructor. |
| |
| |
| // template<class T> |
| // optional(T) -> optional<T>; |
| |
| |
| #include <optional> |
| #include <cassert> |
| |
| struct A {}; |
| |
| int main() |
| { |
| // Test the explicit deduction guides |
| { |
| // optional(T) |
| std::optional opt(5); |
| static_assert(std::is_same_v<decltype(opt), std::optional<int>>, ""); |
| assert(static_cast<bool>(opt)); |
| assert(*opt == 5); |
| } |
| |
| { |
| // optional(T) |
| std::optional opt(A{}); |
| static_assert(std::is_same_v<decltype(opt), std::optional<A>>, ""); |
| assert(static_cast<bool>(opt)); |
| } |
| |
| // Test the implicit deduction guides |
| { |
| // optional(optional); |
| std::optional<char> source('A'); |
| std::optional opt(source); |
| static_assert(std::is_same_v<decltype(opt), std::optional<char>>, ""); |
| assert(static_cast<bool>(opt) == static_cast<bool>(source)); |
| assert(*opt == *source); |
| } |
| } |