forked from mirror/libcxx
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
55 lines
1.4 KiB
C++
55 lines
1.4 KiB
C++
//===----------------------------------------------------------------------===//
|
|
//
|
|
// 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);
|
|
}
|
|
}
|