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
72 lines
1.5 KiB
C++
72 lines
1.5 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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// void reset() 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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using std::optional;
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struct X
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{
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static bool dtor_called;
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~X() {dtor_called = true;}
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};
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bool X::dtor_called = false;
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constexpr bool check_reset()
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{
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{
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optional<int> opt;
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static_assert(noexcept(opt.reset()) == true, "");
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opt.reset();
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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.reset();
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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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check_reset();
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#if TEST_STD_VER >= 20
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static_assert(check_reset());
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#endif
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{
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optional<X> opt;
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static_assert(noexcept(opt.reset()) == true, "");
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assert(X::dtor_called == false);
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opt.reset();
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assert(X::dtor_called == false);
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assert(static_cast<bool>(opt) == false);
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}
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{
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optional<X> opt(X{});
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X::dtor_called = false;
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opt.reset();
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assert(X::dtor_called == true);
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assert(static_cast<bool>(opt) == false);
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X::dtor_called = false;
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}
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return 0;
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}
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