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35ce4859dd
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
94 lines
1.9 KiB
C++
94 lines
1.9 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++98, c++03, c++11, c++14
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// <optional>
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// template <class U>
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// optional(optional<U>&& rhs);
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#include <optional>
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#include <type_traits>
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#include <memory>
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#include <cassert>
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#include "test_macros.h"
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using std::optional;
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template <class T, class U>
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void
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test(optional<U>&& rhs, bool is_going_to_throw = false)
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{
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bool rhs_engaged = static_cast<bool>(rhs);
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#ifndef TEST_HAS_NO_EXCEPTIONS
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try
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{
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optional<T> lhs = std::move(rhs);
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assert(is_going_to_throw == false);
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assert(static_cast<bool>(lhs) == rhs_engaged);
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}
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catch (int i)
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{
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assert(i == 6);
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}
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#else
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if (is_going_to_throw) return;
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optional<T> lhs = std::move(rhs);
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assert(static_cast<bool>(lhs) == rhs_engaged);
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#endif
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}
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class X
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{
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int i_;
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public:
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X(int i) : i_(i) {}
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X(X&& x) : i_(std::exchange(x.i_, 0)) {}
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~X() {i_ = 0;}
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friend bool operator==(const X& x, const X& y) {return x.i_ == y.i_;}
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};
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int count = 0;
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struct Z
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{
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Z(int) { TEST_THROW(6); }
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};
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int main()
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{
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{
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optional<short> rhs;
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test<int>(std::move(rhs));
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}
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{
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optional<short> rhs(short{3});
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test<int>(std::move(rhs));
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}
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{
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optional<int> rhs;
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test<X>(std::move(rhs));
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}
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{
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optional<int> rhs(3);
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test<X>(std::move(rhs));
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}
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{
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optional<int> rhs;
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test<Z>(std::move(rhs));
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}
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{
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optional<int> rhs(3);
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test<Z>(std::move(rhs), true);
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}
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static_assert(!(std::is_constructible<optional<X>, optional<Z>>::value), "");
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}
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