[{"id":3681909,"web_url":"http://patchwork.ozlabs.org/comment/3681909/","msgid":"","list_archive_url":null,"date":"2026-04-24T09:20:50","subject":"Re: [PATCH] libstdc+: Provide iterator type for basic_const_iterator.","submitter":{"id":48004,"url":"http://patchwork.ozlabs.org/api/people/48004/","name":"Jonathan Wakely","email":"jwakely@redhat.com"},"content":"On Fri, 24 Apr 2026 at 09:57, Tomasz Kamiński wrote:\n>\n> This resolves 4253. basic_const_iterator should provide iterator_type.\n\nI think this would be more readable as:\n\nThis resolves LWG 4253, \"basic_const_iterator should provide iterator_type\"\nwhich was approved in Kona 2025.\n\nOK with that change, thanks\n\n\n>\n> libstdc++-v3/ChangeLog:\n>\n> * include/bits/stl_iterator.h (basic_const_iterator::iterator_type):\n> Define.\n> * testsuite/24_iterators/const_iterator/1.cc: Tests for\n> iterator_type.\n> ---\n> Tested on x86_64-linux. OK for trunk?\n>\n> libstdc++-v3/include/bits/stl_iterator.h | 3 +++\n> libstdc++-v3/testsuite/24_iterators/const_iterator/1.cc | 2 ++\n> 2 files changed, 5 insertions(+)\n>\n> diff --git a/libstdc++-v3/include/bits/stl_iterator.h b/libstdc++-v3/include/bits/stl_iterator.h\n> index f16f591ad63..6439deb608a 100644\n> --- a/libstdc++-v3/include/bits/stl_iterator.h\n> +++ b/libstdc++-v3/include/bits/stl_iterator.h\n> @@ -2691,6 +2691,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n> template friend class basic_const_iterator;\n>\n> public:\n> + // _GLIBCXX_RESOLVE_LIB_DEFECTS\n> + // 4253. basic_const_iterator should provide iterator_type\n> + using iterator_type = _It;\n> using iterator_concept = decltype(_S_iter_concept());\n> using value_type = iter_value_t<_It>;\n> using difference_type = iter_difference_t<_It>;\n> diff --git a/libstdc++-v3/testsuite/24_iterators/const_iterator/1.cc b/libstdc++-v3/testsuite/24_iterators/const_iterator/1.cc\n> index f2bcad4f09c..7f791ddbef9 100644\n> --- a/libstdc++-v3/testsuite/24_iterators/const_iterator/1.cc\n> +++ b/libstdc++-v3/testsuite/24_iterators/const_iterator/1.cc\n> @@ -29,6 +29,7 @@ test01()\n> else\n> {\n> using Wrapped = std::basic_const_iterator;\n> + static_assert( std::same_as );\n>\n> static_assert( std::same_as, Wrapped> );\n> static_assert( std::same_as, Wrapped> );\n> @@ -64,6 +65,7 @@ test02()\n> {\n> static_assert( !ranges::constant_range );\n> using Wrapped = std::basic_const_iterator>;\n> + static_assert( std::same_as> );\n>\n> if constexpr (Constable)\n> {\n> --\n> 2.53.0\n>","headers":{"Return-Path":"","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=Jbxs9Igb;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=38.145.34.32; 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