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GET /api/patches/2227950/?format=api
{ "id": 2227950, "url": "http://patchwork.ozlabs.org/api/patches/2227950/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/patch/20260424152301.2386133-1-tkaminsk@redhat.com/", "project": { "id": 17, "url": "http://patchwork.ozlabs.org/api/projects/17/?format=api", "name": "GNU Compiler Collection", "link_name": "gcc", "list_id": "gcc-patches.gcc.gnu.org", "list_email": "gcc-patches@gcc.gnu.org", "web_url": null, "scm_url": null, "webscm_url": null, "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20260424152301.2386133-1-tkaminsk@redhat.com>", "list_archive_url": null, "date": "2026-04-24T15:21:56", "name": "[v2] libstdc++: Disallow duration of cv-qualified types and references.", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "c5edc409f75ae557180b3c9dad523fa1d64aea0a", "submitter": { "id": 90409, "url": "http://patchwork.ozlabs.org/api/people/90409/?format=api", "name": "Tomasz Kamiński", "email": "tkaminsk@redhat.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/gcc/patch/20260424152301.2386133-1-tkaminsk@redhat.com/mbox/", "series": [ { "id": 501381, "url": "http://patchwork.ozlabs.org/api/series/501381/?format=api", "web_url": "http://patchwork.ozlabs.org/project/gcc/list/?series=501381", "date": "2026-04-24T15:21:56", "name": "[v2] libstdc++: Disallow duration of cv-qualified types and references.", "version": 2, "mbox": "http://patchwork.ozlabs.org/series/501381/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2227950/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2227950/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "gcc-patches@gcc.gnu.org" ], "Delivered-To": [ "patchwork-incoming@legolas.ozlabs.org", "gcc-patches@gcc.gnu.org" ], "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=Uq+bFeUm;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=2620:52:6:3111::32; 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charset=\"US-ASCII\"; x-default=true", "X-BeenThere": "gcc-patches@gcc.gnu.org", "X-Mailman-Version": "2.1.30", "Precedence": "list", "List-Id": "Gcc-patches mailing list <gcc-patches.gcc.gnu.org>", "List-Unsubscribe": "<https://gcc.gnu.org/mailman/options/gcc-patches>,\n <mailto:gcc-patches-request@gcc.gnu.org?subject=unsubscribe>", "List-Archive": "<https://gcc.gnu.org/pipermail/gcc-patches/>", "List-Post": "<mailto:gcc-patches@gcc.gnu.org>", "List-Help": "<mailto:gcc-patches-request@gcc.gnu.org?subject=help>", "List-Subscribe": "<https://gcc.gnu.org/mailman/listinfo/gcc-patches>,\n <mailto:gcc-patches-request@gcc.gnu.org?subject=subscribe>", "Errors-To": "gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org" }, "content": "This implements LWG 4481, \"Disallow chrono::duration<const T, P>\",\nwhich was approved in Croydon 2026.\n\nlibstdc++-v3/ChangeLog:\n\n\t* include/bits/chrono.h: Add static_assert requiring cv-unqualified\n\tnon-reference type.\n\t* testsuite/20_util/duration/io.cc: Remove const-qualifier in\n\tstream manipluators tests.\n\t* testsuite/20_util/duration/requirements/typedefs_neg4.cc:\n\tNew test.\n---\nv2 removes const from manipulators test instead of nuking them completly.\n\nTesting on x86_64-linux. *duration* test passed again.\nOK for trunk when all tests passes?\n\n libstdc++-v3/include/bits/chrono.h | 4 ++++\n libstdc++-v3/testsuite/20_util/duration/io.cc | 12 ++++++------\n .../20_util/duration/requirements/typedefs_neg4.cc | 11 +++++++++++\n 3 files changed, 21 insertions(+), 6 deletions(-)\n create mode 100644 libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg4.cc", "diff": "diff --git a/libstdc++-v3/include/bits/chrono.h b/libstdc++-v3/include/bits/chrono.h\nindex fd91505c16f..d639cfaa485 100644\n--- a/libstdc++-v3/include/bits/chrono.h\n+++ b/libstdc++-v3/include/bits/chrono.h\n@@ -514,6 +514,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n template<typename _Rep, typename _Period>\n class duration\n {\n+\t// _GLIBCXX_RESOLVE_LIB_DEFECTS\n+\t// 4481. Disallow chrono::duration<const T, P>\n+\tstatic_assert(is_same<_Rep, __remove_cvref_t<_Rep>>::value,\n+\t\t \"rep should be cv-unqualified object type\");\n \tstatic_assert(!__is_duration<_Rep>::value,\n \t\t \"rep cannot be a std::chrono::duration\");\n \tstatic_assert(__is_ratio<_Period>::value,\ndiff --git a/libstdc++-v3/testsuite/20_util/duration/io.cc b/libstdc++-v3/testsuite/20_util/duration/io.cc\nindex 6ada4fcfa84..83ecd33c038 100644\n--- a/libstdc++-v3/testsuite/20_util/duration/io.cc\n+++ b/libstdc++-v3/testsuite/20_util/duration/io.cc\n@@ -40,10 +40,10 @@ test01()\n VERIFY( ss.str() == \"121s 122s 123s 124s 125s 126s 127s \" );\n \n ss.str(\"\");\n- ss << std::hex << std::uppercase << duration<const char>(0x1A) << ' ';\n- ss << std::hex << std::uppercase << duration<const wchar_t>(0x2A) << ' ';\n+ ss << std::hex << std::uppercase << duration<char>(0x1A) << ' ';\n+ ss << std::hex << std::uppercase << duration<wchar_t>(0x2A) << ' ';\n ss << std::hex << std::uppercase << duration<signed char>(0x3A) << ' ';\n- ss << std::scientific << duration<const double>(4.5) << ' ';\n+ ss << std::scientific << duration<double>(4.5) << ' ';\n VERIFY( ss.str() == \"1As 2As 3As 4.500000E+00s \" );\n }\n \n@@ -79,10 +79,10 @@ test02()\n VERIFY( ss.str() == L\"121s 122s 123s 124s 125s 126s 127s \" );\n \n ss.str(L\"\");\n- ss << std::hex << std::uppercase << duration<const char>(0x1A) << ' ';\n- ss << std::hex << std::uppercase << duration<const wchar_t>(0x2A) << ' ';\n+ ss << std::hex << std::uppercase << duration<char>(0x1A) << ' ';\n+ ss << std::hex << std::uppercase << duration<wchar_t>(0x2A) << ' ';\n ss << std::hex << std::uppercase << duration<signed char>(0x3A) << ' ';\n- ss << std::scientific << duration<const double>(4.5) << ' ';\n+ ss << std::scientific << duration<double>(4.5) << ' ';\n VERIFY( ss.str() == L\"1As 2As 3As 4.500000E+00s \" );\n #endif\n }\ndiff --git a/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg4.cc b/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg4.cc\nnew file mode 100644\nindex 00000000000..52a5d92cc8b\n--- /dev/null\n+++ b/libstdc++-v3/testsuite/20_util/duration/requirements/typedefs_neg4.cc\n@@ -0,0 +1,11 @@\n+// { dg-do compile { target c++11 } }\n+\n+#include <chrono>\n+\n+const int i = 10;\n+// Check if rep is a cv-unqualifed object type\n+std::chrono::duration<const int> d1(i); // { dg-error \"required from here\" }\n+std::chrono::duration<volatile int> d2(i); // { dg-error \"required from here\" }\n+std::chrono::duration<const int&> d3(i); // { dg-error \"required from here\" }\n+\n+// { dg-error \"rep should be cv-unqualified object type\" \"\" { target *-*-* } 0 }\n", "prefixes": [ "v2" ] }