a9e659619f
Summary: Adapt implementation of Library Fundamentals TS optional into an implementation of N4606 optional. - Update relational operators per http://wg21.link/P0307 - Update to requirements of http://wg21.link/P0032 - Extension: Implement trivial copy/move construction/assignment for `optional<T>` when `T` is trivially copyable. Audit P/Rs for optional LWG issues: - 2756 "C++ WP optional<T> should 'forward' T's implicit conversions" Implemented, which also resolves 2753 "Optional's constructors and assignments need constraints" (modulo my refusal to explicitly delete the move operations, which is a design error that I'm working on correcting in the 2756 P/R). - 2736 "nullopt_t insufficiently constrained" Already conforming. I've added a test ensuring that `nullopt_t` is not copy-initializable from an empty braced-init-list, which I believe is the root intent of the issue, to avoid regression. - 2740 "constexpr optional<T>::operator->" Already conforming. - 2746 "Inconsistency between requirements for emplace between optional and variant" No P/R, but note that the author's '"suggested resolution" is already implemented. - 2748 "swappable traits for optionals" Already conforming. - 2753 "Optional's constructors and assignments need constraints" Implemented. Most of the work for this patch was done by Casey Carter @ Microsoft. Thank you Casey! Reviewers: mclow.lists, CaseyCarter, EricWF Differential Revision: https://reviews.llvm.org/D22741 llvm-svn: 283980
49 lines
1.4 KiB
C++
49 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.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
// UNSUPPORTED: c++98, c++03, c++11, c++14
|
|
// <optional>
|
|
|
|
// template <class T> struct hash<optional<T>>;
|
|
|
|
#include <optional>
|
|
#include <string>
|
|
#include <memory>
|
|
#include <cassert>
|
|
|
|
|
|
int main()
|
|
{
|
|
using std::optional;
|
|
const std::size_t nullopt_hash =
|
|
std::hash<optional<double>>{}(optional<double>{});
|
|
|
|
{
|
|
typedef int T;
|
|
optional<T> opt;
|
|
assert(std::hash<optional<T>>{}(opt) == nullopt_hash);
|
|
opt = 2;
|
|
assert(std::hash<optional<T>>{}(opt) == std::hash<T>{}(*opt));
|
|
}
|
|
{
|
|
typedef std::string T;
|
|
optional<T> opt;
|
|
assert(std::hash<optional<T>>{}(opt) == nullopt_hash);
|
|
opt = std::string("123");
|
|
assert(std::hash<optional<T>>{}(opt) == std::hash<T>{}(*opt));
|
|
}
|
|
{
|
|
typedef std::unique_ptr<int> T;
|
|
optional<T> opt;
|
|
assert(std::hash<optional<T>>{}(opt) == nullopt_hash);
|
|
opt = std::unique_ptr<int>(new int(3));
|
|
assert(std::hash<optional<T>>{}(opt) == std::hash<T>{}(*opt));
|
|
}
|
|
}
|