From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id 45E273858412 for ; Tue, 28 Sep 2021 17:08:44 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 45E273858412 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-265-Va-KBleCNXWqEzym9h6WSw-1; Tue, 28 Sep 2021 13:08:42 -0400 X-MC-Unique: Va-KBleCNXWqEzym9h6WSw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 21D2C8E4AA1; Tue, 28 Sep 2021 17:08:41 +0000 (UTC) Received: from localhost (unknown [10.33.36.241]) by smtp.corp.redhat.com (Postfix) with ESMTP id C0C1A19C79; Tue, 28 Sep 2021 17:08:40 +0000 (UTC) Date: Tue, 28 Sep 2021 18:08:40 +0100 From: Jonathan Wakely To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: [committed] libstdc++: Improve std::forward static assert message Message-ID: MIME-Version: 1.0 X-Clacks-Overhead: GNU Terry Pratchett X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/mixed; boundary="ddPtk8HFTV2NskKE" Content-Disposition: inline X-Spam-Status: No, score=-13.8 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 28 Sep 2021 17:08:45 -0000 --ddPtk8HFTV2NskKE Content-Type: text/plain; charset=us-ascii Content-Disposition: inline The previous message told you something was wrong, but not why it happened or why it's bad. This changes it to explain that the function is being misused. Signed-off-by: Jonathan Wakely libstdc++-v3/ChangeLog: * include/bits/move.h (forward(remove_reference_t&&)): Improve text of static_assert. * testsuite/20_util/forward/c_neg.cc: Adjust dg-error. * testsuite/20_util/forward/f_neg.cc: Likewise. Tested x86_64-linux. Committed to trunk. --ddPtk8HFTV2NskKE Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="patch.txt" commit a11052d98db2f2a61841f0c5ee84de4ca1b3e296 Author: Jonathan Wakely Date: Tue Sep 28 12:35:29 2021 libstdc++: Improve std::forward static assert message The previous message told you something was wrong, but not why it happened or why it's bad. This changes it to explain that the function is being misused. Signed-off-by: Jonathan Wakely libstdc++-v3/ChangeLog: * include/bits/move.h (forward(remove_reference_t&&)): Improve text of static_assert. * testsuite/20_util/forward/c_neg.cc: Adjust dg-error. * testsuite/20_util/forward/f_neg.cc: Likewise. diff --git a/libstdc++-v3/include/bits/move.h b/libstdc++-v3/include/bits/move.h index 3abbb37ceeb..2dd7ed9e4f9 100644 --- a/libstdc++-v3/include/bits/move.h +++ b/libstdc++-v3/include/bits/move.h @@ -88,8 +88,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION constexpr _Tp&& forward(typename std::remove_reference<_Tp>::type&& __t) noexcept { - static_assert(!std::is_lvalue_reference<_Tp>::value, "template argument" - " substituting _Tp must not be an lvalue reference type"); + static_assert(!std::is_lvalue_reference<_Tp>::value, + "std::forward must not be used to convert an rvalue to an lvalue"); return static_cast<_Tp&&>(__t); } diff --git a/libstdc++-v3/testsuite/20_util/forward/c_neg.cc b/libstdc++-v3/testsuite/20_util/forward/c_neg.cc index dc7ec51bde6..3875792866e 100644 --- a/libstdc++-v3/testsuite/20_util/forward/c_neg.cc +++ b/libstdc++-v3/testsuite/20_util/forward/c_neg.cc @@ -17,7 +17,7 @@ // with this library; see the file COPYING3. If not see // . -// { dg-error "must not be an lvalue reference" "" { target *-*-* } 0 } +// { dg-error "convert an rvalue to an lvalue" "" { target *-*-* } 0 } #include diff --git a/libstdc++-v3/testsuite/20_util/forward/f_neg.cc b/libstdc++-v3/testsuite/20_util/forward/f_neg.cc index 4ccd7264c65..51ccaf29c1a 100644 --- a/libstdc++-v3/testsuite/20_util/forward/f_neg.cc +++ b/libstdc++-v3/testsuite/20_util/forward/f_neg.cc @@ -17,7 +17,7 @@ // with this library; see the file COPYING3. If not see // . -// { dg-error "must not be an lvalue reference" "" { target *-*-* } 0 } +// { dg-error "convert an rvalue to an lvalue" "" { target *-*-* } 0 } #include --ddPtk8HFTV2NskKE--