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[libc++] Verifies std::forward_like's mandates clause. #127318

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Merged
merged 1 commit into from
Mar 27, 2025
Merged

[libc++] Verifies std::forward_like's mandates clause. #127318

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2 changes: 1 addition & 1 deletion libcxx/docs/Status/Cxx23Issues.csv
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Original file line number Diff line number Diff line change
Expand Up @@ -213,7 +213,7 @@
"`LWG3753 <https://wg21.link/LWG3753>`__","Clarify entity vs. freestanding entity","2022-11 (Kona)","","",""
"`LWG3754 <https://wg21.link/LWG3754>`__","Class template expected synopsis contains declarations that do not match the detailed description","2022-11 (Kona)","|Nothing To Do|","",""
"`LWG3755 <https://wg21.link/LWG3755>`__","``tuple-for-each`` can call ``user-defined`` ``operator,``","2022-11 (Kona)","|Complete|","17",""
"`LWG3757 <https://wg21.link/LWG3757>`__","What's the effect of ``std::forward_like<void>(x)``?","2022-11 (Kona)","","",""
"`LWG3757 <https://wg21.link/LWG3757>`__","What's the effect of ``std::forward_like<void>(x)``?","2022-11 (Kona)","|Nothing To Do|","",""
"`LWG3759 <https://wg21.link/LWG3759>`__","``ranges::rotate_copy`` should use ``std::move``","2022-11 (Kona)","|Complete|","15",""
"`LWG3760 <https://wg21.link/LWG3760>`__","``cartesian_product_view::iterator``'s ``parent_`` is never valid","2022-11 (Kona)","","",""
"`LWG3761 <https://wg21.link/LWG3761>`__","``cartesian_product_view::iterator::operator-`` should pass by reference","2022-11 (Kona)","","",""
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46 changes: 46 additions & 0 deletions libcxx/test/std/utilities/utility/forward/forward_like.verify.cpp
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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// REQUIRES: std-at-least-c++23

// <utility>

// template <typename T>
// [[nodiscard]] constexpr
// auto forward_like(auto&& x) noexcept -> see below;

// Mandates: T is a referenceable type (3.45 [defns.referenceable]).

#include <utility>

struct incomplete;

void test() {
int i;
(void)std::forward_like<incomplete>(i);

(void)std::forward_like<void>(i); // expected-error {{no matching function for call to 'forward_like'}}
(void)std::forward_like<const void>(i); // expected-error {{no matching function for call to 'forward_like'}}
(void)std::forward_like<volatile void>(i); // expected-error {{no matching function for call to 'forward_like'}}
(void)std::forward_like<const volatile void>(i); // expected-error {{no matching function for call to 'forward_like'}}

using fp = void();
using cfp = void() const;
using vfp = void() volatile;
using cvfp = void() const volatile;
(void)std::forward_like<fp>(i);
(void)std::forward_like<cfp>(i); // expected-error {{no matching function for call to 'forward_like'}}
(void)std::forward_like<cfp>(i); // expected-error {{no matching function for call to 'forward_like'}}
(void)std::forward_like<vfp>(i); // expected-error {{no matching function for call to 'forward_like'}}
(void)std::forward_like<cvfp>(i); // expected-error {{no matching function for call to 'forward_like'}}

using fpr = void()&;
using fprr = void()&&;
(void)std::forward_like<fpr>(i); // expected-error {{no matching function for call to 'forward_like'}}
(void)std::forward_like<fprr>(i); // expected-error {{no matching function for call to 'forward_like'}}
}