4 files changed, 27 insertions, 13 deletions

diff --git a/libstdc++-v3/include/debug/forward_list b/libstdc++-v3/include/debug/forward_list
index 4e1511d..9da7dda 100644
--- a/libstdc++-v3/include/debug/forward_list
+++ b/libstdc++-v3/include/debug/forward_list
@@ -144,13 +144,13 @@ namespace __gnu_debug
       //std::swap(_M_this()->_M_version, __other._M_version);
       _Safe_iterator_base* __this_its = _M_this()->_M_iterators;
       _S_swap_aux(__other, __other._M_iterators,
-		  _M_this(), _M_this()->_M_iterators);
+		  *_M_this(), _M_this()->_M_iterators);
       _Safe_iterator_base* __this_const_its = _M_this()->_M_const_iterators;
       _S_swap_aux(__other, __other._M_const_iterators,
-		  _M_this(), _M_this()->_M_const_iterators);
-      _S_swap_aux(_M_this(), __this_its,
+		  *_M_this(), _M_this()->_M_const_iterators);
+      _S_swap_aux(*_M_this(), __this_its,
 		  __other, __other._M_iterators);
-      _S_swap_aux(_M_this(), __this_const_its,
+      _S_swap_aux(*_M_this(), __this_const_its,
 		  __other, __other._M_const_iterators);
     }
 
diff --git a/libstdc++-v3/include/std/format b/libstdc++-v3/include/std/format
index 5749aa1..d584b81 100644
--- a/libstdc++-v3/include/std/format
+++ b/libstdc++-v3/include/std/format
@@ -6030,13 +6030,13 @@ namespace __format
 
       constexpr void
       set_separator(basic_string_view<_CharT> __sep) noexcept
-	requires (!_S_range_format_is_string)
+	requires (format_kind<_Rg> == range_format::sequence)
       { _M_under.set_separator(__sep); }
 
       constexpr void
       set_brackets(basic_string_view<_CharT> __open,
 		   basic_string_view<_CharT> __close) noexcept
-	requires (!_S_range_format_is_string)
+	requires (format_kind<_Rg> == range_format::sequence)
       { _M_under.set_brackets(__open, __close); }
 
       // We deviate from standard, that declares this as template accepting
diff --git a/libstdc++-v3/include/std/mdspan b/libstdc++-v3/include/std/mdspan
index 5a42aea..5d16de5 100644
--- a/libstdc++-v3/include/std/mdspan
+++ b/libstdc++-v3/include/std/mdspan
@@ -406,10 +406,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     template<typename _IndexType, size_t... _Counts>
       auto __build_dextents_type(integer_sequence<size_t, _Counts...>)
 	-> extents<_IndexType, ((void) _Counts, dynamic_extent)...>;
-
-    template<typename _Tp>
-      consteval size_t
-      __dynamic_extent() { return dynamic_extent; }
   }
 
   template<typename _IndexType, size_t _Rank>
@@ -419,7 +415,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<typename... _Integrals>
     requires (is_convertible_v<_Integrals, size_t> && ...)
     explicit extents(_Integrals...) ->
-      extents<size_t, __mdspan::__dynamic_extent<_Integrals>()...>;
+      extents<size_t, __detail::__maybe_static_ext<_Integrals>...>;
 
   struct layout_left
   {
@@ -1316,7 +1312,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	      && (sizeof...(_Integrals) > 0)
     explicit mdspan(_ElementType*, _Integrals...)
     -> mdspan<_ElementType,
-	      extents<size_t, __mdspan::__dynamic_extent<_Integrals>()...>>;
+	      extents<size_t, __detail::__maybe_static_ext<_Integrals>...>>;
 
   template<typename _ElementType, typename _OIndexType, size_t _Nm>
     mdspan(_ElementType*, span<_OIndexType, _Nm>)
diff --git a/libstdc++-v3/include/std/span b/libstdc++-v3/include/std/span
index 49ab910..5629a71 100644
--- a/libstdc++-v3/include/std/span
+++ b/libstdc++-v3/include/std/span
@@ -476,6 +476,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     };
 
   // deduction guides
+  namespace __detail
+  {
+    template<typename _Tp>
+      concept __integral_constant_like = is_integral_v<decltype(_Tp::value)>
+	&& !is_same_v<bool, remove_const_t<decltype(_Tp::value)>>
+	&& convertible_to<_Tp, decltype(_Tp::value)>
+	&& equality_comparable_with<_Tp, decltype(_Tp::value)>
+	&& bool_constant<_Tp() == _Tp::value>::value
+	&& bool_constant<static_cast<decltype(_Tp::value)>(_Tp()) == _Tp::value>
+	     ::value;
+
+    template<typename _Tp>
+      constexpr size_t __maybe_static_ext = dynamic_extent;
+
+    template<__integral_constant_like _Tp>
+      constexpr size_t __maybe_static_ext<_Tp> = {_Tp::value};
+  }
 
   template<typename _Type, size_t _ArrayExtent>
     span(_Type(&)[_ArrayExtent]) -> span<_Type, _ArrayExtent>;
@@ -489,7 +506,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   template<contiguous_iterator _Iter, typename _End>
     span(_Iter, _End)
-      -> span<remove_reference_t<iter_reference_t<_Iter>>>;
+      -> span<remove_reference_t<iter_reference_t<_Iter>>,
+				 __detail::__maybe_static_ext<_End>>;
 
   template<ranges::contiguous_range _Range>
     span(_Range &&)