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
73 lines
1.5 KiB
C++
73 lines
1.5 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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// constexpr T& optional<T>::value() &&;
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#include <optional>
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#include <type_traits>
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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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using std::bad_optional_access;
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struct X
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{
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X() = default;
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X(const X&) = delete;
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constexpr int test() const & {return 3;}
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int test() & {return 4;}
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constexpr int test() const && {return 5;}
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int test() && {return 6;}
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};
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struct Y
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{
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constexpr int test() && {return 7;}
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};
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constexpr int
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test()
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{
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optional<Y> opt{Y{}};
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return std::move(opt).value().test();
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}
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int main()
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{
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{
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optional<X> opt; ((void)opt);
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ASSERT_NOT_NOEXCEPT(std::move(opt).value());
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ASSERT_SAME_TYPE(decltype(std::move(opt).value()), X&&);
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}
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{
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optional<X> opt;
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opt.emplace();
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assert(std::move(opt).value().test() == 6);
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}
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#ifndef TEST_HAS_NO_EXCEPTIONS
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{
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optional<X> opt;
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try
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{
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std::move(opt).value();
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assert(false);
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}
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catch (const bad_optional_access&)
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{
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}
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}
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#endif
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static_assert(test() == 7, "");
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}
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