[committed] libstdc++: Add code comment documenting LWG 4027 change [PR118083]

[Patrick Palka]

Tested on x86_64-pc-linxu-gnu, pushed to trunk as obvious.

-- >8 --

	PR libstdc++/118083

libstdc++-v3/ChangeLog:

	* include/bits/ranges_base.h
	(ranges::__access::__possibly_const_range): Mention LWG 4027.
---
 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 28fe64a9e9d..516d04afdab 100644
--- a/libstdc++-v3/include/bits/ranges_base.h
+++ b/libstdc++-v3/include/bits/ranges_base.h
@@ -646,6 +646,8 @@ 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
-- 
2.48.1.431.g5a526e5e18