[gcc r12-6692] libstdc++: Use __cpp_lib_concepts in std::reverse_iterator [PR104098]

[gcc r12-6692] libstdc++: Use __cpp_lib_concepts in std::reverse_iterator [PR104098]

[Jonathan Wakely]

https://gcc.gnu.org/g:e13e95bd274148a825bc9527efac49e99080dd64

commit r12-6692-ge13e95bd274148a825bc9527efac49e99080dd64
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Jan 18 15:34:24 2022 +0000

    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.

Diff:
---
 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