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

[Jonathan Wakely via Gcc-patches]

Tested powerpc64le-linux, pushed to trunk.


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.
---
 libstdc++-v3/include/bits/stl_iterator.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/include/bits/stl_iterator.h 
b/libstdc++-v3/include/bits/stl_iterator.h
index 549a391d04d..266ddd02a78 100644
--- a/libstdc++-v3/include/bits/stl_iterator.h
+++ b/libstdc++-v3/include/bits/stl_iterator.h
@@ -94,7 +94,7 @@ _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,
@@ -155,7 +155,7 @@ _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
-- 
2.31.1