a0c00ccd5f
Updates the implementation `std::reference_wrapper` - [P2944R3](https://wg21.link/P2944R3) as discussed in https://github.com/llvm/llvm-project/pull/117664#discussion_r1857826166 This PR also refactors the tests in preparation to implements the constrained comparisons for `optional`, `variant` etc. - Moves the test helpers (concepts and types) for testing constrained comparisons to `test_comparisons.h`. - Updates the `std::reference_wrapper` implementation to use the concept `__core_convertible_to<bool>` as per comments in #135759. Closes #138233 # References: - [refwrap.comparisons](https://wg21.link/refwrap.comparisons) --------- Co-authored-by: Hristo Hristov <zingam@outlook.com> Co-authored-by: Nikolas Klauser <nikolasklauser@berlin.de>
90 lines
2.3 KiB
C++
90 lines
2.3 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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// REQUIRES: std-at-least-c++26
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// <functional>
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// class reference_wrapper
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// [refwrap.comparisons], comparisons
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// friend constexpr auto operator<=>(reference_wrapper, reference_wrapper); // Since C++26
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#include <cassert>
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#include <concepts>
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#include <functional>
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#include "test_comparisons.h"
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#include "test_macros.h"
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// Test SFINAE.
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static_assert(HasOperatorSpaceship<std::reference_wrapper<StrongOrder>>);
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static_assert(HasOperatorSpaceship<std::reference_wrapper<WeakOrder>>);
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static_assert(HasOperatorSpaceship<std::reference_wrapper<PartialOrder>>);
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static_assert(!HasOperatorSpaceship<std::reference_wrapper<NonComparable>>);
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// Test comparisons.
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template <typename T, typename Order>
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constexpr void test() {
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T t{47};
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T bigger{94};
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T smaller{82};
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T unordered{std::numeric_limits<int>::min()};
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// Identical contents
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{
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std::reference_wrapper<T> rw1{t};
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std::reference_wrapper<T> rw2{t};
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assert(testOrder(rw1, rw2, Order::equivalent));
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}
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// Less
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{
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std::reference_wrapper<T> rw1{smaller};
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std::reference_wrapper<T> rw2{bigger};
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assert(testOrder(rw1, rw2, Order::less));
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}
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// Greater
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{
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std::reference_wrapper<T> rw1{bigger};
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std::reference_wrapper<T> rw2{smaller};
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assert(testOrder(rw1, rw2, Order::greater));
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}
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// Unordered
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if constexpr (std::same_as<T, PartialOrder>) {
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std::reference_wrapper<T> rw1{bigger};
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std::reference_wrapper<T> rw2{unordered};
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assert(testOrder(rw1, rw2, Order::unordered));
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}
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}
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constexpr bool test() {
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test<int, std::strong_ordering>();
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test<StrongOrder, std::strong_ordering>();
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test<int, std::weak_ordering>();
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test<WeakOrder, std::weak_ordering>();
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test<int, std::partial_ordering>();
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test<PartialOrder, std::partial_ordering>();
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// `LessAndEqComp` does not have `operator<=>`. Ordering is synthesized based on `operator<`
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test<LessAndEqComp, std::weak_ordering>();
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return true;
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}
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int main(int, char**) {
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test();
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static_assert(test());
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return 0;
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}
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