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 [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id A5DA93858412 for ; Sat, 12 Nov 2022 11:24:02 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org A5DA93858412 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668252242; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type; bh=t0lTG6fxypUxk3Pq9JFOPo1F9X2gtxJAcZAVysWf13w=; b=X6TDteAa1fthIe3pGbMAG+8xxpI52X2iAzAXY2Wj96YFUrSfGV6Y/oMdHlZMJflXvQi3kx lE8nSis4NsUfv1mTWrJ+6aeHSZk2HBWHdZDPZNOy8NhxRMH/UpnVu9TS2TGUpBgHAZWsFT Z0JEUaL2OLPJvTLohMF5oVLPL72SDPw= 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-318-HEP0nfWbPkGY9GWX2-3SXA-1; Sat, 12 Nov 2022 06:24:00 -0500 X-MC-Unique: HEP0nfWbPkGY9GWX2-3SXA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9FD8D3803905 for ; Sat, 12 Nov 2022 11:24:00 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.192.38]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5D6612166B26; Sat, 12 Nov 2022 11:24:00 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.17.1/8.17.1) with ESMTPS id 2ACBNtYZ954418 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Sat, 12 Nov 2022 12:23:56 +0100 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 2ACBNt9X954417; Sat, 12 Nov 2022 12:23:55 +0100 Date: Sat, 12 Nov 2022 12:23:54 +0100 From: Jakub Jelinek To: Jason Merrill Cc: gcc-patches@gcc.gnu.org Subject: [PATCH] c++: Implement CWG2635 - Constrained structured bindings Message-ID: Reply-To: Jakub Jelinek MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-3.9 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,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 List-Id: Hi! The following patch implements CWG2635. So far tested on GXX_TESTSUITE_STDS=98,11,14,17,20,2b make check-g++ RUNTESTFLAGS="dg.exp=decomp*" ok for trunk if it passes full bootstrap/regtest and it is voted in? 2022-11-12 Jakub Jelinek * decl.cc (grokdeclarator): Implement CWG2635 - Constrained structured bindings. Diagnose constrained auto type. * g++.dg/cpp2a/decomp5.C: New test. --- gcc/cp/decl.cc.jj 2022-11-11 17:14:33.103869977 +0100 +++ gcc/cp/decl.cc 2022-11-12 12:13:52.217239729 +0100 @@ -12660,7 +12660,8 @@ grokdeclarator (const cp_declarator *dec gcc_unreachable (); } if (TREE_CODE (type) != TEMPLATE_TYPE_PARM - || TYPE_IDENTIFIER (type) != auto_identifier) + || TYPE_IDENTIFIER (type) != auto_identifier + || PLACEHOLDER_TYPE_CONSTRAINTS_INFO (type)) { if (type != error_mark_node) { --- gcc/testsuite/g++.dg/cpp2a/decomp5.C.jj 2022-11-12 12:17:21.024392082 +0100 +++ gcc/testsuite/g++.dg/cpp2a/decomp5.C 2022-11-12 12:20:00.700214521 +0100 @@ -0,0 +1,20 @@ +// CWG2635 - Constrained structured bindings +// { dg-do compile { target c++20 } } + +namespace std { + template struct tuple_size; + template struct tuple_element; +} + +struct A { + int i; + A(int x) : i(x) {} + template int& get() { return i; } +}; + +template<> struct std::tuple_size { static const int value = 2; }; +template struct std::tuple_element { using type = int; }; + +template concept C = true; +C auto [x, y] = A{1}; // { dg-error "structured binding declaration cannot have type 'auto \\\[requires ::C<, >\\\]'" } + // { dg-message "type must be cv-qualified 'auto' or reference to cv-qualified 'auto'" "" { target *-*-* } .-1 } Jakub