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
75 lines
3.0 KiB
C++
75 lines
3.0 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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#include <optional>
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#include <type_traits>
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#include <cassert>
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#include "archetypes.hpp"
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template <class T>
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struct SpecialMemberTest {
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using O = std::optional<T>;
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static_assert(std::is_default_constructible_v<O>,
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"optional is always default constructible.");
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static_assert(std::is_copy_constructible_v<O> == std::is_copy_constructible_v<T>,
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"optional<T> is copy constructible if and only if T is copy constructible.");
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static_assert(std::is_move_constructible_v<O> ==
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(std::is_copy_constructible_v<T> || std::is_move_constructible_v<T>),
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"optional<T> is move constructible if and only if T is copy or move constructible.");
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static_assert(std::is_copy_assignable_v<O> ==
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(std::is_copy_constructible_v<T> && std::is_copy_assignable_v<T>),
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"optional<T> is copy assignable if and only if T is both copy "
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"constructible and copy assignable.");
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static_assert(std::is_move_assignable_v<O> ==
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((std::is_copy_constructible_v<T> && std::is_copy_assignable_v<T>) ||
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(std::is_move_constructible_v<T> && std::is_move_assignable_v<T>)),
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"optional<T> is move assignable if and only if T is both move assignable and "
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"move constructible, or both copy constructible and copy assignable.");
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};
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template <class ...Args> static void sink(Args&&...) {}
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template <class ...TestTypes>
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struct DoTestsMetafunction {
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DoTestsMetafunction() { sink(SpecialMemberTest<TestTypes>{}...); }
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};
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struct TrivialMoveNonTrivialCopy {
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TrivialMoveNonTrivialCopy() = default;
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TrivialMoveNonTrivialCopy(const TrivialMoveNonTrivialCopy&) {}
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TrivialMoveNonTrivialCopy(TrivialMoveNonTrivialCopy&&) = default;
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TrivialMoveNonTrivialCopy& operator=(const TrivialMoveNonTrivialCopy&) { return *this; }
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TrivialMoveNonTrivialCopy& operator=(TrivialMoveNonTrivialCopy&&) = default;
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};
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struct TrivialCopyNonTrivialMove {
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TrivialCopyNonTrivialMove() = default;
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TrivialCopyNonTrivialMove(const TrivialCopyNonTrivialMove&) = default;
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TrivialCopyNonTrivialMove(TrivialCopyNonTrivialMove&&) {}
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TrivialCopyNonTrivialMove& operator=(const TrivialCopyNonTrivialMove&) = default;
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TrivialCopyNonTrivialMove& operator=(TrivialCopyNonTrivialMove&&) { return *this; }
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};
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int main()
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{
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sink(
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ImplicitTypes::ApplyTypes<DoTestsMetafunction>{},
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ExplicitTypes::ApplyTypes<DoTestsMetafunction>{},
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NonLiteralTypes::ApplyTypes<DoTestsMetafunction>{},
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NonTrivialTypes::ApplyTypes<DoTestsMetafunction>{},
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DoTestsMetafunction<TrivialMoveNonTrivialCopy, TrivialCopyNonTrivialMove>{}
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);
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}
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