[{"id":3674743,"web_url":"http://patchwork.ozlabs.org/comment/3674743/","msgid":"","list_archive_url":null,"date":"2026-04-08T12:34:30","subject":"Re: [PATCH] libstdc++/ranges: Implement LWG 3599 change to\n lazy_split_view","submitter":{"id":4329,"url":"http://patchwork.ozlabs.org/api/people/4329/","name":"Jonathan Wakely","email":"jwakely.gcc@gmail.com"},"content":"OK\n\nOn Wed, 8 Apr 2026, 13:20 Patrick Palka, wrote:\n\n> Tested on x86_64-pc-linux-gnu, does this look OK for trunk/backports?\n>\n> -- >8 --\n>\n> libstdc++-v3/ChangeLog:\n>\n> * include/std/ranges (lazy_split_view::begin): Add\n> const _Pattern contraint on const overload as per LWG 3599.\n> (lazy_split_view::end): Likewise.\n> * testsuite/std/ranges/adaptors/lazy_split.cc (test14): New\n> test.\n> ---\n> libstdc++-v3/include/std/ranges | 4 +++-\n> .../testsuite/std/ranges/adaptors/lazy_split.cc | 10 ++++++++++\n> 2 files changed, 13 insertions(+), 1 deletion(-)\n>\n> diff --git a/libstdc++-v3/include/std/ranges\n> b/libstdc++-v3/include/std/ranges\n> index 0aa4191e04f6..41175fd45e4b 100644\n> --- a/libstdc++-v3/include/std/ranges\n> +++ b/libstdc++-v3/include/std/ranges\n> @@ -3809,6 +3809,7 @@ namespace views::__adaptor\n>\n> constexpr auto\n> begin() const requires forward_range<_Vp> && forward_range _Vp>\n> + && forward_range\n> {\n> return _OuterIter{this, ranges::begin(_M_base)};\n> }\n> @@ -3826,7 +3827,8 @@ namespace views::__adaptor\n> {\n> if constexpr (forward_range<_Vp>\n> && forward_range\n> - && common_range)\n> + && common_range\n> + && forward_range)\n> return _OuterIter{this, ranges::end(_M_base)};\n> else\n> return default_sentinel;\n> diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split.cc\n> b/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split.cc\n> index 60ee7d70580e..1c69b8f27cfd 100644\n> --- a/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split.cc\n> +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split.cc\n> @@ -239,6 +239,15 @@ test13()\n> constexpr decltype(views::lazy_split(views::single(0), 0).begin()) it;\n> }\n>\n> +void\n> +test14()\n> +{\n> + // LWG 3599\n> + auto p = views::iota(0) | views::take(1) | views::reverse;\n> + auto r = views::single(42) | views::lazy_split(p);\n> + auto f = r.front();\n> +}\n> +\n> int\n> main()\n> {\n> @@ -255,4 +264,5 @@ main()\n> test11();\n> static_assert(test12());\n> test13();\n> + test14();\n> }\n> --\n> 2.54.0.rc0.180.g7c4e9e957a\n>\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 (2048-bit key;\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20251104 header.b=nttXVc/U;\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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Wed, 08 Apr 2026\n 05:34:42 -0700 (PDT)","MIME-Version":"1.0","References":"<20260408121941.4047772-1-ppalka@redhat.com>","In-Reply-To":"<20260408121941.4047772-1-ppalka@redhat.com>","From":"Jonathan Wakely ","Date":"Wed, 8 Apr 2026 13:34:30 +0100","X-Gm-Features":"AQROBzAqVXzFThCA7l1zU8IvAU4Cx-K7888rnqSgm9zuR56Z8DZVMbS1U6XiXVY","Message-ID":"\n ","Subject":"Re: [PATCH] libstdc++/ranges: Implement LWG 3599 change to\n lazy_split_view","To":"Patrick Palka ","Cc":"gcc-patches , \"libstdc++\" ","Content-Type":"multipart/alternative; boundary=\"000000000000ca976a064ef21f39\"","X-BeenThere":"gcc-patches@gcc.gnu.org","X-Mailman-Version":"2.1.30","Precedence":"list","List-Id":"Gcc-patches mailing list ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org"}}]