From d03c58584da3c440cc9103d6a69f6c36f16f6e97 Mon Sep 17 00:00:00 2001
From: Patrick Palka <ppalka@redhat.com>
Date: Wed, 26 Feb 2025 14:51:38 -0500
Subject: [PATCH] libstdc++: Add code comment documenting LWG 4027 change
 [PR118083]

	PR libstdc++/118083

libstdc++-v3/ChangeLog:

	* include/bits/ranges_base.h
	(ranges::__access::__possibly_const_range): Mention LWG 4027.

(cherry picked from commit 640697f7c2def415db81c84010ae25be0785d867)
---
 libstdc++-v3/include/bits/ranges_base.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libstdc++-v3/include/bits/ranges_base.h b/libstdc++-v3/include/bits/ranges_base.h
index 481d9bb5c5d..eafd982f48e 100644
--- a/libstdc++-v3/include/bits/ranges_base.h
+++ b/libstdc++-v3/include/bits/ranges_base.h
@@ -635,6 +635,8 @@ namespace ranges
       constexpr auto&
       __possibly_const_range(_Range& __r) noexcept
       {
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 4027. possibly-const-range should prefer returning const R&
 	if constexpr (input_range<const _Range>)
 	  return const_cast<const _Range&>(__r);
 	else
-- 
2.47.2