From: Jonathan Wakely <jwakely@redhat.com>
Date: Tue, 18 Jan 2022 15:34:24 +0000 (+0000)
Subject: libstdc++: Use __cpp_lib_concepts in std::reverse_iterator [PR104098]
X-Git-Tag: releases/gcc-11.3.0~129
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f6bf63ff3684c28c3b2c4d3a67a42db738d6342d;p=thirdparty%2Fgcc.git

libstdc++: Use __cpp_lib_concepts in std::reverse_iterator [PR104098]

We should not assume that std::iter_value_t etc. are defined
unconditionally for C++20 mode.

libstdc++-v3/ChangeLog:

	PR libstdc++/104098
	* include/bits/stl_iterator.h (reverse_iterator): Check
	__cpp_lib_concepts instead of __cplusplus.

(cherry picked from commit e13e95bd274148a825bc9527efac49e99080dd64)
---

diff --git a/libstdc++-v3/include/bits/stl_iterator.h b/libstdc++-v3/include/bits/stl_iterator.h
index 2b7efcbf3c3a..79e9959fc58e 100644
--- a/libstdc++-v3/include/bits/stl_iterator.h
+++ b/libstdc++-v3/include/bits/stl_iterator.h
@@ -93,7 +93,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    * @{
    */
 
-#if __cplusplus > 201703L && __cpp_lib_concepts
+#if __cpp_lib_concepts
   namespace __detail
   {
     // Weaken iterator_category _Cat to _Limit if it is derived from that,
@@ -150,7 +150,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     public:
       typedef _Iterator					iterator_type;
       typedef typename __traits_type::pointer		pointer;
-#if __cplusplus <= 201703L
+#if ! __cpp_lib_concepts
       typedef typename __traits_type::difference_type	difference_type;
       typedef typename __traits_type::reference		reference;
 #else