546449938a
Makes the following operations constexpr: * `std::swap(optional, optional)` * `optional(optional<U> const&)` * `optional(optional<U>&&)` * `~optional()` * `operator=(nullopt_t)` * `operator=(U&&)` * `operator=(optional<U> const&)` * `operator=(optional<U>&&)` * `emplace(Args&&...)` * `emplace(initializer_list<U>, Args&&...)` * `swap(optional&)` * `reset()` P2231 has been accepted by plenary, with the committee recommending implementers retroactively apply to C++20. It's necessary for us to implement _`semiregular-box`_ and _`non-propagating-cache`_, both of which are required for ranges (otherwise we'll need to reimplement `std::optional` with these members `constexpr`ified). Differential Revision: https://reviews.llvm.org/D102119
105 lines
2.6 KiB
C++
105 lines
2.6 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14
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// <optional>
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// optional<T>& operator=(nullopt_t) noexcept;
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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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#include "archetypes.h"
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using std::optional;
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using std::nullopt_t;
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using std::nullopt;
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TEST_CONSTEXPR_CXX20 bool test()
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{
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enum class State { inactive, constructed, destroyed };
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State state = State::inactive;
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struct StateTracker {
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TEST_CONSTEXPR_CXX20 StateTracker(State& s)
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: state_(&s)
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{
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s = State::constructed;
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}
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TEST_CONSTEXPR_CXX20 ~StateTracker() { *state_ = State::destroyed; }
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State* state_;
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};
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{
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optional<int> opt;
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static_assert(noexcept(opt = nullopt) == true, "");
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opt = nullopt;
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assert(static_cast<bool>(opt) == false);
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}
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{
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optional<int> opt(3);
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opt = nullopt;
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assert(static_cast<bool>(opt) == false);
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}
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{
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optional<StateTracker> opt;
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opt = nullopt;
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assert(state == State::inactive);
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assert(static_cast<bool>(opt) == false);
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}
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{
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optional<StateTracker> opt(state);
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assert(state == State::constructed);
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opt = nullopt;
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assert(state == State::destroyed);
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assert(static_cast<bool>(opt) == false);
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}
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return true;
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}
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int main(int, char**)
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{
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#if TEST_STD_VER > 17
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static_assert(test());
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#endif
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test();
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using TT = TestTypes::TestType;
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TT::reset();
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{
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optional<TT> opt;
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static_assert(noexcept(opt = nullopt) == true, "");
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assert(TT::destroyed == 0);
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opt = nullopt;
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assert(TT::constructed == 0);
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assert(TT::alive == 0);
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assert(TT::destroyed == 0);
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assert(static_cast<bool>(opt) == false);
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}
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assert(TT::alive == 0);
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assert(TT::destroyed == 0);
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TT::reset();
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{
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optional<TT> opt(42);
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assert(TT::destroyed == 0);
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TT::reset_constructors();
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opt = nullopt;
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assert(TT::constructed == 0);
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assert(TT::alive == 0);
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assert(TT::destroyed == 1);
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assert(static_cast<bool>(opt) == false);
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}
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assert(TT::alive == 0);
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assert(TT::destroyed == 1);
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TT::reset();
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return 0;
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}
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