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Implement N4606 optional

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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

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283980 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eric Fiselier
2016-10-12 07:46:20 +00:00
parent ead5d404cc
commit 35ce4859dd
86 changed files with 8473 additions and 56 deletions
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39
test/std/utilities/optional/optional.nullops/greater.pass.cpp Normal file
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//===----------------------------------------------------------------------===//
//
// 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> constexpr bool operator>(const optional<T>& x, nullopt_t) noexcept;
// template <class T> constexpr bool operator>(nullopt_t, const optional<T>& x) noexcept;
#include <optional>
int main()
{
using std::optional;
using std::nullopt_t;
using std::nullopt;
{
typedef int T;
typedef optional<T> O;
constexpr O o1; // disengaged
constexpr O o2{1}; // engaged
static_assert ( !(nullopt > o1), "" );
static_assert ( !(nullopt > o2), "" );
static_assert ( !(o1 > nullopt), "" );
static_assert ( (o2 > nullopt), "" );
static_assert (noexcept(nullopt > o1), "");
static_assert (noexcept(o1 > nullopt), "");
}
}