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[8.43.85.97]) by mx.google.com with ESMTPS id g1-20020a50ee01000000b004c1147e963esi788656eds.502.2023.03.10.11.08.31 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Mar 2023 11:08:31 -0800 (PST) Received-SPF: pass (google.com: domain of gcc-patches-bounces+ouuuleilei=gmail.com@gcc.gnu.org designates 8.43.85.97 as permitted sender) client-ip=8.43.85.97; Authentication-Results: mx.google.com; dkim=pass header.i=@gcc.gnu.org header.s=default header.b=jUlgbjxC; spf=pass (google.com: domain of gcc-patches-bounces+ouuuleilei=gmail.com@gcc.gnu.org designates 8.43.85.97 as permitted sender) smtp.mailfrom="gcc-patches-bounces+ouuuleilei=gmail.com@gcc.gnu.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gnu.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 94F6B385842D for ; Fri, 10 Mar 2023 19:08:30 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 94F6B385842D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1678475310; bh=DJ4x88mlJzFFfRDYyO8RjfPTwe0OQIa/liY5+xwIzsw=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=jUlgbjxC+j46MZ6BAoCMgzYvhh9kmjb+eJQr5gA76g6nguD2fc2Wn5Pk3MK/Ve+F8 qOeb/Qe9dJgN1BF8Pe62BUwzy8kzlonMoXf2wooySV+a/xz3s41oGENUCeKKH9OXsL PNQcqHxPUF1hmVYy3BcBM65ak8C9f35Tx5gso6jI= X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 742363858D32 for ; Fri, 10 Mar 2023 19:07:46 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 742363858D32 Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-44-G6BlXXsOMIiXFfh-7G9Mqw-1; Fri, 10 Mar 2023 14:07:44 -0500 X-MC-Unique: G6BlXXsOMIiXFfh-7G9Mqw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4B3082932495 for ; Fri, 10 Mar 2023 19:07:44 +0000 (UTC) Received: from pdp-11.redhat.com (unknown [10.22.9.9]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2249B440D8; Fri, 10 Mar 2023 19:07:44 +0000 (UTC) To: GCC Patches , Jason Merrill Subject: [PATCH] c++: suppress -Wdangling-reference for std::span [PR107532] Date: Fri, 10 Mar 2023 14:07:41 -0500 Message-Id: <20230310190741.168444-1-polacek@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-12.4 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) 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-Patchwork-Original-From: Marek Polacek via Gcc-patches From: Marek Polacek Reply-To: Marek Polacek Errors-To: gcc-patches-bounces+ouuuleilei=gmail.com@gcc.gnu.org Sender: "Gcc-patches" X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1760008928342352816?= X-GMAIL-MSGID: =?utf-8?q?1760008928342352816?= std::span is a view and therefore should be treated as a reference wrapper class for the purposes of -Wdangling-reference. I'm not sure there's a pattern that we could check for. Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? PR c++/107532 gcc/cp/ChangeLog: * call.cc (reference_like_class_p): Check for std::span. gcc/testsuite/ChangeLog: * g++.dg/warn/Wdangling-reference10.C: New test. --- gcc/cp/call.cc | 1 + gcc/testsuite/g++.dg/warn/Wdangling-reference10.C | 12 ++++++++++++ 2 files changed, 13 insertions(+) create mode 100644 gcc/testsuite/g++.dg/warn/Wdangling-reference10.C base-commit: 20d790aa3ea5b0d240032cab997b8e0938cac62c diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc index 3dfa12a0733..c01e7b82457 100644 --- a/gcc/cp/call.cc +++ b/gcc/cp/call.cc @@ -13800,6 +13800,7 @@ reference_like_class_p (tree ctype) tree name = DECL_NAME (tdecl); return (name && (id_equal (name, "reference_wrapper") + || id_equal (name, "span") || id_equal (name, "ref_view"))); } for (tree fields = TYPE_FIELDS (ctype); diff --git a/gcc/testsuite/g++.dg/warn/Wdangling-reference10.C b/gcc/testsuite/g++.dg/warn/Wdangling-reference10.C new file mode 100644 index 00000000000..733fb8cce63 --- /dev/null +++ b/gcc/testsuite/g++.dg/warn/Wdangling-reference10.C @@ -0,0 +1,12 @@ +// PR c++/107532 +// { dg-do compile { target c++20 } } +// { dg-options "-Wdangling-reference" } + +#include +#include + +void f(const std::vector& v) +{ + const int& r = std::span(v)[0]; // { dg-bogus "dangling reference" } + (void) r; +}