diff --git a/source/algorithms.tex b/source/algorithms.tex
index fbe42e26fa..04cb156bc8 100644
--- a/source/algorithms.tex
+++ b/source/algorithms.tex
@@ -6206,6 +6206,7 @@
 \end{note}
 
 \pnum
+\indexdefn{sequence!sorted!with respect to a comparator and projection}%
 A sequence is \term{sorted with respect to a \tcode{comp} and \tcode{proj}}
 for a comparator and projection \tcode{comp} and \tcode{proj}
 if for every iterator \tcode{i} pointing to the sequence and
@@ -6217,6 +6218,13 @@
 \end{codeblock}
 is \tcode{false}.
 
+\pnum
+\indexdefn{sequence!sorted!with respect to a comparator}%
+A sequence is \term{sorted with respect to a comparator} \tcode{comp}
+for a comparator \tcode{comp}
+if it is sorted with respect to
+\tcode{comp} and \tcode{identity\{\}} (the identity projection).
+
 \pnum
 A sequence \range{start}{finish} is
 \term{partitioned with respect to an expression} \tcode{f(e)}
diff --git a/source/containers.tex b/source/containers.tex
index bf2b4b012c..72cabef394 100644
--- a/source/containers.tex
+++ b/source/containers.tex
@@ -10515,7 +10515,8 @@
     insert_return_type insert(node_type&& nh);
     iterator           insert(const_iterator hint, node_type&& nh);
 
-    iterator  erase(iterator position);
+    iterator  erase(iterator position)
+      requires (!@\libconcept{same_as}@<iterator, const_iterator>);
     iterator  erase(const_iterator position);
     size_type erase(const key_type& x);
     template<class K> size_type erase(K&& x);
@@ -10827,7 +10828,8 @@
     iterator insert(node_type&& nh);
     iterator insert(const_iterator hint, node_type&& nh);
 
-    iterator  erase(iterator position);
+    iterator  erase(iterator position)
+      requires (!@\libconcept{same_as}@<iterator, const_iterator>);
     iterator  erase(const_iterator position);
     size_type erase(const key_type& x);
     template<class K> size_type erase(K&& x);
@@ -12359,7 +12361,8 @@
     insert_return_type insert(node_type&& nh);
     iterator           insert(const_iterator hint, node_type&& nh);
 
-    iterator  erase(iterator position);
+    iterator  erase(iterator position)
+      requires (!@\libconcept{same_as}@<iterator, const_iterator>);
     iterator  erase(const_iterator position);
     size_type erase(const key_type& k);
     template<class K> size_type erase(K&& x);
@@ -12732,7 +12735,8 @@
     iterator insert(node_type&& nh);
     iterator insert(const_iterator hint, node_type&& nh);
 
-    iterator  erase(iterator position);
+    iterator  erase(iterator position)
+      requires (!@\libconcept{same_as}@<iterator, const_iterator>);
     iterator  erase(const_iterator position);
     size_type erase(const key_type& k);
     template<class K> size_type erase(K&& x);
diff --git a/source/future.tex b/source/future.tex
index 609e7cfceb..2f13822f8f 100644
--- a/source/future.tex
+++ b/source/future.tex
@@ -2639,8 +2639,6 @@
     void atomic_init(atomic<T>*, typename atomic<T>::value_type) noexcept;
 
   #define ATOMIC_VAR_INIT(value) @\seebelow@
-
-  #define ATOMIC_FLAG_INIT @\seebelow@
 }
 \end{codeblock}
 
@@ -2709,25 +2707,3 @@
 \end{codeblock}
 \end{example}
 \end{itemdescr}
-
-\rSec2[depr.atomics.flag]{Flag type and operations}
-
-\indexlibraryglobal{ATOMIC_FLAG_INIT}%
-\begin{itemdecl}
-#define ATOMIC_FLAG_INIT @\seebelow@
-\end{itemdecl}
-
-\begin{itemdescr}
-\pnum
-\remarks
-The macro \tcode{ATOMIC_FLAG_INIT} is defined in such a way that
-it can be used to initialize an object of type \tcode{atomic_flag}
-to the clear state.
-The macro can be used in the form:
-\begin{codeblock}
-atomic_flag guard = ATOMIC_FLAG_INIT;
-\end{codeblock}
-It is unspecified whether the macro can be used
-in other initialization contexts.
-For a complete static-duration object, that initialization shall be static.
-\end{itemdescr}
diff --git a/source/iostreams.tex b/source/iostreams.tex
index ac91f6ed3a..51e6fb05af 100644
--- a/source/iostreams.tex
+++ b/source/iostreams.tex
@@ -15757,6 +15757,10 @@
     directory_iterator&    operator++();
     directory_iterator&    increment(error_code& ec);
 
+    bool operator==(default_sentinel_t) const noexcept {
+      return *this == directory_iterator();
+    }
+
     // other members as required by \ref{input.iterators}, input iterators
   };
 }
@@ -16003,6 +16007,10 @@
     void pop(error_code& ec);
     void disable_recursion_pending();
 
+    bool operator==(default_sentinel_t) const noexcept {
+      return *this == recursive_directory_iterator();
+    }
+
     // other members as required by \ref{input.iterators}, input iterators
   };
 }
diff --git a/source/iterators.tex b/source/iterators.tex
index 0b49fb07bc..9c9606b0ae 100644
--- a/source/iterators.tex
+++ b/source/iterators.tex
@@ -4796,7 +4796,7 @@
     constexpr decltype(auto) operator*();
     constexpr decltype(auto) operator*() const
       requires @\exposconcept{dereferenceable}@<const I>;
-    constexpr decltype(auto) operator->() const
+    constexpr auto operator->() const
       requires @\seebelow@;
 
     constexpr common_iterator& operator++();
@@ -4964,7 +4964,7 @@
 
 \indexlibrarymember{operator->}{common_iterator}%
 \begin{itemdecl}
-constexpr decltype(auto) operator->() const
+constexpr auto operator->() const
   requires @\seebelow@;
 \end{itemdecl}
 
diff --git a/source/lib-intro.tex b/source/lib-intro.tex
index 555f81b7d5..4dbbdcd82b 100644
--- a/source/lib-intro.tex
+++ b/source/lib-intro.tex
@@ -492,9 +492,11 @@
 \indexlibrary{decay-copy@\tcode{\placeholder{decay-copy}}}%
 \begin{codeblock}
 namespace std {
-  template<class T> constexpr decay_t<T> @\placeholdernc{decay-copy}@(T&& v)
-      noexcept(is_nothrow_convertible_v<T, decay_t<T>>)         // \expos
-    { return std::forward<T>(v); }
+  template<class T>
+    requires @\libconcept{convertible_to}@<T, decay_t<T>>
+      constexpr decay_t<T> @\placeholdernc{decay-copy}@(T&& v)
+        noexcept(is_nothrow_convertible_v<T, decay_t<T>>)       // \expos
+      { return std::forward<T>(v); }
 
   constexpr auto @\placeholdernc{synth-three-way}@ =
     []<class T, class U>(const T& t, const U& u)
diff --git a/source/memory.tex b/source/memory.tex
index 349c18b115..8491e64339 100644
--- a/source/memory.tex
+++ b/source/memory.tex
@@ -5442,6 +5442,12 @@
     polymorphic_allocator select_on_container_copy_construction() const;
 
     memory_resource* resource() const;
+
+    // friends
+    friend bool operator==(const polymorphic_allocator& a,
+                           const polymorphic_allocator& b) noexcept {
+      return *a.resource() == *b.resource();
+    }
   };
 }
 \end{codeblock}
diff --git a/source/ranges.tex b/source/ranges.tex
index c1b1795099..ead1940263 100644
--- a/source/ranges.tex
+++ b/source/ranges.tex
@@ -1537,11 +1537,17 @@
     }
 
   public:
-    constexpr bool empty() requires @\libconcept{forward_range}@<D> {
-      return ranges::begin(@\exposid{derived}@()) == ranges::end(@\exposid{derived}@());
+    constexpr bool empty() requires @\libconcept{sized_range}@<D> || @\libconcept{forward_range}@<D> {
+      if constexpr (@\libconcept{sized_range}@<D>)
+        return ranges::size(@\exposid{derived}@()) == 0;
+      else
+        return ranges::begin(@\exposid{derived}@()) == ranges::end(@\exposid{derived}@());
     }
-    constexpr bool empty() const requires @\libconcept{forward_range}@<const D> {
-      return ranges::begin(@\exposid{derived}@()) == ranges::end(@\exposid{derived}@());
+    constexpr bool empty() const requires @\libconcept{sized_range}@<const D> || @\libconcept{forward_range}@<const D> {
+      if constexpr (@\libconcept{sized_range}@<const D>)
+        return ranges::size(@\exposid{derived}@()) == 0;
+      else
+        return ranges::begin(@\exposid{derived}@()) == ranges::end(@\exposid{derived}@());
     }
 
     constexpr explicit operator bool()
@@ -2767,7 +2773,8 @@
     W @\exposid{value_}@ = W();             // \expos
   public:
     using iterator_concept = @\seebelow@;
-    using iterator_category = input_iterator_tag;       // present only if \tcode{W} models \libconcept{incrementable}
+    using iterator_category = input_iterator_tag;       // present only if \tcode{W} models \libconcept{incrementable} and
+                                                        // \tcode{\placeholdernc{IOTA-DIFF-T}(W)} is an integral type
     using value_type = W;
     using difference_type = @\placeholdernc{IOTA-DIFF-T}@(W);
 
@@ -4430,7 +4437,7 @@
     using iterator_concept  = @\seebelownc@;
     using iterator_category = @\seebelownc@;                        // not always present
     using value_type        =
-      remove_cvref_t<invoke_result_t<F&, range_reference_t<@\exposid{Base}@>>>;
+      remove_cvref_t<invoke_result_t<@\exposidnc{maybe-const}@<Const, F>&, range_reference_t<@\exposid{Base}@>>>;
     using difference_type   = range_difference_t<@\exposid{Base}@>;
 
     @\exposid{iterator}@() requires @\libconcept{default_initializable}@<iterator_t<@\exposid{Base}@>> = default;
@@ -4514,7 +4521,7 @@
 \tcode{iterator_traits<iterator_t<\exposid{Base}>>::iterator_category}.
 \begin{itemize}
 \item
-If \tcode{is_lvalue_reference_v<invoke_result_t<F\&, range_reference_t<\exposid{Base}>>>}
+If \tcode{is_lvalue_reference_v<invoke_result_t<\exposidnc{maybe-const}<Const, F>\&, range_reference_t<\linebreak\exposid{Base}>>>}
 is \tcode{true}, then
 \begin{itemize}
 \item
@@ -5322,7 +5329,7 @@
 \begin{itemdescr}
 \pnum
 \effects
-Initializes \exposid{end_} with \tcode{s.\exposid{end_}} and
+Initializes \exposid{end_} with \tcode{std::move(s.\exposid{end_})} and
 \exposid{pred_} with \tcode{s.\exposid{pred_}}.
 \end{itemdescr}
 
@@ -8741,17 +8748,8 @@
     friend constexpr bool operator==(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
       requires (@\libconcept{equality_comparable}@<iterator_t<@\exposid{maybe-const}@<Const, Views>>> && ...);
 
-    friend constexpr bool operator<(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-      requires @\exposconcept{all-random-access}@<Const, Views...>;
-    friend constexpr bool operator>(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-      requires @\exposconcept{all-random-access}@<Const, Views...>;
-    friend constexpr bool operator<=(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-      requires @\exposconcept{all-random-access}@<Const, Views...>;
-    friend constexpr bool operator>=(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-      requires @\exposconcept{all-random-access}@<Const, Views...>;
     friend constexpr auto operator<=>(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-      requires @\exposconcept{all-random-access}@<Const, Views...> &&
-               (@\libconcept{three_way_comparable}@<iterator_t<@\exposid{maybe-const}@<Const, Views>>> && ...);
+      requires @\exposconcept{all-random-access}@<Const, Views...>;
 
     friend constexpr @\exposid{iterator}@ operator+(const @\exposid{iterator}@& i, difference_type n)
       requires @\exposconcept{all-random-access}@<Const, Views...>;
@@ -8973,54 +8971,9 @@
 \end{itemize}
 \end{itemdescr}
 
-\begin{itemdecl}
-friend constexpr bool operator<(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-  requires @\exposconcept{all-random-access}@<Const, Views...>;
-\end{itemdecl}
-
-\begin{itemdescr}
-\pnum
-\returns
-\tcode{x.\exposid{current_} < y.\exposid{current_}}.
-\end{itemdescr}
-
-\begin{itemdecl}
-friend constexpr bool operator>(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-  requires @\exposconcept{all-random-access}@<Const, Views...>;
-\end{itemdecl}
-
-\begin{itemdescr}
-\pnum
-\effects
-Equivalent to: \tcode{return y < x;}
-\end{itemdescr}
-
-\begin{itemdecl}
-friend constexpr bool operator<=(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-  requires @\exposconcept{all-random-access}@<Const, Views...>;
-\end{itemdecl}
-
-\begin{itemdescr}
-\pnum
-\effects
-Equivalent to: \tcode{return !(y < x);}
-\end{itemdescr}
-
-\begin{itemdecl}
-friend constexpr bool operator>=(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-  requires @\exposconcept{all-random-access}@<Const, Views...>;
-\end{itemdecl}
-
-\begin{itemdescr}
-\pnum
-\effects
-Equivalent to: \tcode{return !(x < y);}
-\end{itemdescr}
-
 \begin{itemdecl}
 friend constexpr auto operator<=>(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-  requires @\exposconcept{all-random-access}@<Const, Views...> &&
-            (@\libconcept{three_way_comparable}@<iterator_t<@\exposid{maybe-const}@<Const, Views>>> && ...);
+  requires @\exposconcept{all-random-access}@<Const, Views...>;
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -9419,16 +9372,8 @@
     friend constexpr bool operator==(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
       requires @\libconcept{equality_comparable}@<@\exposid{ziperator}@<Const>>;
 
-    friend constexpr bool operator<(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-      requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
-    friend constexpr bool operator>(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-      requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
-    friend constexpr bool operator<=(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-      requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
-    friend constexpr bool operator>=(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-      requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
     friend constexpr auto operator<=>(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-      requires @\libconcept{random_access_range}@<@\exposid{Base}@> && @\libconcept{three_way_comparable}@<@\exposid{ziperator}@<Const>>;
+      requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
 
     friend constexpr @\exposid{iterator}@ operator+(const @\exposid{iterator}@& i, difference_type n)
       requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
@@ -9640,16 +9585,8 @@
 \begin{itemdecl}
 friend constexpr bool operator==(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
   requires @\libconcept{equality_comparable}@<@\exposid{ziperator}@<Const>>;
-friend constexpr bool operator<(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-  requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
-friend constexpr bool operator>(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-  requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
-friend constexpr bool operator<=(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-  requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
-friend constexpr bool operator>=(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-  requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
 friend constexpr auto operator<=>(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-  requires @\libconcept{random_access_range}@<@\exposid{Base}@> && @\libconcept{three_way_comparable}@<@\exposid{ziperator}@<Const>>;
+  requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -10988,8 +10925,8 @@
   template<@\libconcept{view}@ V>
     requires @\libconcept{input_range}@<V>
   class chunk_view : public view_interface<chunk_view<V>> {
-    V @\exposid{base_}@ = V();                                        // \expos
-    range_difference_t<V> @\exposid{n_}@ = 0;                         // \expos
+    V @\exposid{base_}@;                                              // \expos
+    range_difference_t<V> @\exposid{n_}@;                             // \expos
     range_difference_t<V> @\exposid{remainder_}@ = 0;                 // \expos
 
     @\exposid{non-propagating-cache}@<iterator_t<V>> @\exposid{current_}@;       // \expos
@@ -11001,14 +10938,13 @@
     class @\exposid{inner-iterator}@;                                 // \expos
 
   public:
-    chunk_view() requires @\libconcept{default_initializable}@<V> = default;
     constexpr explicit chunk_view(V base, range_difference_t<V> n);
 
     constexpr V base() const & requires @\libconcept{copy_constructible}@<V> { return @\exposid{base_}@; }
     constexpr V base() && { return std::move(@\exposid{base_}@); }
 
     constexpr @\exposid{outer-iterator}@ begin();
-    constexpr default_sentinel_t end() noexcept;
+    constexpr default_sentinel_t end() const noexcept;
 
     constexpr auto size() requires @\libconcept{sized_range}@<V>;
     constexpr auto size() const requires @\libconcept{sized_range}@<const V>;
@@ -11050,7 +10986,7 @@
 \end{itemdescr}
 
 \begin{itemdecl}
-constexpr default_sentinel_t end() noexcept;
+constexpr default_sentinel_t end() const noexcept;
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -11267,7 +11203,8 @@
 \effects
 Equivalent to:
 \begin{codeblock}
-return ranges::min(@\exposid{parent_}@->@\exposid{remainder_}@, ranges::end(@\exposid{parent_}@->@\exposid{base_}@) - *@\exposid{parent_}@->@\exposid{current_}@);
+return @\exposid{to-unsigned-like}@(ranges::min(@\exposid{parent_}@->@\exposid{remainder_}@,
+	                            ranges::end(@\exposid{parent_}@->@\exposid{base_}@) - *@\exposid{parent_}@->@\exposid{current_}@));
 \end{codeblock}
 \end{itemdescr}
 
@@ -11419,14 +11356,13 @@
   template<@\libconcept{view}@ V>
     requires @\libconcept{forward_range}@<V>
   class chunk_view<V> : public view_interface<chunk_view<V>> {
-    V @\exposid{base_}@ = V();                      // \expos
-    range_difference_t<V> @\exposid{n_}@ = 0;       // \expos
+    V @\exposid{base_}@;                            // \expos
+    range_difference_t<V> @\exposid{n_}@;           // \expos
 
     // \ref{range.chunk.fwd.iter}, class template \tcode{chunk_view::\exposid{iterator}}
     template<bool> class @\exposid{iterator}@;      // \expos
 
   public:
-    chunk_view() requires @\libconcept{default_initializable}@<V> = default;
     constexpr explicit chunk_view(V base, range_difference_t<V> n);
 
     constexpr V base() const & requires @\libconcept{copy_constructible}@<V> { return @\exposid{base_}@; }
@@ -11952,8 +11888,8 @@
   template<@\libconcept{forward_range}@ V>
     requires @\libconcept{view}@<V>
   class slide_view : public view_interface<slide_view<V>> {
-    V @\exposid{base_}@ = V();                      // \expos
-    range_difference_t<V> @\exposid{n_}@ = 0;       // \expos
+    V @\exposid{base_}@;                            // \expos
+    range_difference_t<V> @\exposid{n_}@;           // \expos
 
     // \ref{range.slide.iterator}, class template \tcode{slide_view::\exposid{iterator}}
     template<bool> class @\exposid{iterator}@;      // \expos
@@ -11962,7 +11898,6 @@
     class @\exposid{sentinel}@;                     // \expos
 
   public:
-    slide_view() requires @\libconcept{default_initializable}@<V> = default;
     constexpr explicit slide_view(V base, range_difference_t<V> n);
 
     constexpr auto begin()
@@ -11987,6 +11922,10 @@
 \end{itemdecl}
 
 \begin{itemdescr}
+\pnum
+\expects
+\tcode{n > 0} is \tcode{true}.
+
 \pnum
 \effects
 Initializes \exposid{base_} with \tcode{std::move(base)} and
diff --git a/source/regex.tex b/source/regex.tex
index 5ee8aa28ed..963a3d0630 100644
--- a/source/regex.tex
+++ b/source/regex.tex
@@ -3228,6 +3228,7 @@
       regex_iterator(const regex_iterator&);
       regex_iterator& operator=(const regex_iterator&);
       bool operator==(const regex_iterator&) const;
+      bool operator==(default_sentinel_t) const { return *this == regex_iterator(); }
       const value_type& operator*() const;
       const value_type* operator->() const;
       regex_iterator& operator++();
@@ -3533,6 +3534,7 @@
       regex_token_iterator(const regex_token_iterator&);
       regex_token_iterator& operator=(const regex_token_iterator&);
       bool operator==(const regex_token_iterator&) const;
+      bool operator==(default_sentinel_t) const { return *this == regex_token_iterator(); }
       const value_type& operator*() const;
       const value_type* operator->() const;
       regex_token_iterator& operator++();
diff --git a/source/strings.tex b/source/strings.tex
index 8e9ae733a0..ad2a4aeee8 100644
--- a/source/strings.tex
+++ b/source/strings.tex
@@ -1972,16 +1972,11 @@
 
   // \ref{basic.string.hash}, hash support
   template<class T> struct hash;
-  template<> struct hash<string>;
-  template<> struct hash<u8string>;
-  template<> struct hash<u16string>;
-  template<> struct hash<u32string>;
-  template<> struct hash<wstring>;
-  template<> struct hash<pmr::string>;
-  template<> struct hash<pmr::u8string>;
-  template<> struct hash<pmr::u16string>;
-  template<> struct hash<pmr::u32string>;
-  template<> struct hash<pmr::wstring>;
+  template<class A> struct hash<basic_string<char, char_traits<char>, A>>;
+  template<class A> struct hash<basic_string<char8_t, char_traits<char8_t>, A>>;
+  template<class A> struct hash<basic_string<char16_t, char_traits<char16_t>, A>>;
+  template<class A> struct hash<basic_string<char32_t, char_traits<char32_t>, A>>;
+  template<class A> struct hash<basic_string<wchar_t, char_traits<wchar_t>, A>>;
 
   inline namespace literals {
   inline namespace string_literals {
@@ -5290,25 +5285,13 @@
 
 \rSec2[basic.string.hash]{Hash support}
 
-\indexlibrarymember{hash}{string}%
-\indexlibrarymember{hash}{u16string}%
-\indexlibrarymember{hash}{u32string}%
-\indexlibrarymember{hash}{wstring}%
-\indexlibrarymember{hash}{pmr::string}%
-\indexlibrarymember{hash}{pmr::u16string}%
-\indexlibrarymember{hash}{pmr::u32string}%
-\indexlibrarymember{hash}{pmr::wstring}%
-\begin{itemdecl}
-template<> struct hash<string>;
-template<> struct hash<u8string>;
-template<> struct hash<u16string>;
-template<> struct hash<u32string>;
-template<> struct hash<wstring>;
-template<> struct hash<pmr::string>;
-template<> struct hash<pmr::u8string>;
-template<> struct hash<pmr::u16string>;
-template<> struct hash<pmr::u32string>;
-template<> struct hash<pmr::wstring>;
+\indexlibrarymember{hash}{basic_string}%
+\begin{itemdecl}
+template<class A> struct hash<basic_string<char, char_traits<char>, A>>;
+template<class A> struct hash<basic_string<char8_t, char_traits<char8_t>, A>>;
+template<class A> struct hash<basic_string<char16_t, char_traits<char16_t>, A>>;
+template<class A> struct hash<basic_string<char32_t, char_traits<char32_t>, A>>;
+template<class A> struct hash<basic_string<wchar_t, char_traits<wchar_t>, A>>;
 \end{itemdecl}
 
 \begin{itemdescr}
diff --git a/source/threads.tex b/source/threads.tex
index 16de6eba03..020915bf95 100644
--- a/source/threads.tex
+++ b/source/threads.tex
@@ -2298,6 +2298,7 @@
   void atomic_flag_notify_one(atomic_flag*) noexcept;
   void atomic_flag_notify_all(volatile atomic_flag*) noexcept;
   void atomic_flag_notify_all(atomic_flag*) noexcept;
+  #define ATOMIC_FLAG_INIT @\seebelow@
 
   // \ref{atomics.fences}, fences
   extern "C" void atomic_thread_fence(memory_order) noexcept;
@@ -5651,6 +5652,26 @@
 This function is an atomic notifying operation\iref{atomics.wait}.
 \end{itemdescr}
 
+\indexlibraryglobal{ATOMIC_FLAG_INIT}%
+\begin{itemdecl}
+#define ATOMIC_FLAG_INIT @\seebelow@
+\end{itemdecl}
+
+\begin{itemdescr}
+\pnum
+\remarks
+The macro \tcode{ATOMIC_FLAG_INIT} is defined in such a way that
+it can be used to initialize an object of type \tcode{atomic_flag}
+to the clear state.
+The macro can be used in the form:
+\begin{codeblock}
+atomic_flag guard = ATOMIC_FLAG_INIT;
+\end{codeblock}
+It is unspecified whether the macro can be used
+in other initialization contexts.
+For a complete static-duration object, that initialization shall be static.
+\end{itemdescr}
+
 \rSec2[atomics.fences]{Fences}
 
 \pnum
@@ -5819,14 +5840,17 @@
 using std::@\libglobal{atomic_fetch_add_explicit}@;                    // \seebelow
 using std::@\libglobal{atomic_fetch_sub}@;                             // \seebelow
 using std::@\libglobal{atomic_fetch_sub_explicit}@;                    // \seebelow
-using std::@\libglobal{atomic_fetch_or}@;                              // \seebelow
-using std::@\libglobal{atomic_fetch_or_explicit}@;                     // \seebelow
 using std::@\libglobal{atomic_fetch_and}@;                             // \seebelow
 using std::@\libglobal{atomic_fetch_and_explicit}@;                    // \seebelow
+using std::@\libglobal{atomic_fetch_or}@;                              // \seebelow
+using std::@\libglobal{atomic_fetch_or_explicit}@;                     // \seebelow
+using std::@\libglobal{atomic_fetch_xor}@;                             // \seebelow
+using std::@\libglobal{atomic_fetch_xor_explicit}@;                    // \seebelow
 using std::@\libglobal{atomic_flag_test_and_set}@;                     // \seebelow
 using std::@\libglobal{atomic_flag_test_and_set_explicit}@;            // \seebelow
 using std::@\libglobal{atomic_flag_clear}@;                            // \seebelow
 using std::@\libglobal{atomic_flag_clear_explicit}@;                   // \seebelow
+#define ATOMIC_FLAG_INIT @\seebelow@
 
 using std::@\libglobal{atomic_thread_fence}@;                          // \seebelow
 using std::@\libglobal{atomic_signal_fence}@;                          // \seebelow
@@ -11316,9 +11340,11 @@
 \begin{itemize}
 \item
 \tcode{F::operator()} is a non-static member function and
-\tcode{decltype(\brk{}\&F::operator())} is of the form
+\tcode{decltype(\brk{}\&F::operator())} is either of the form
 \tcode{R(G::*)(A...)}~\cv{}~\tcode{\opt{\&}~\opt{noexcept}}
-for a class type \tcode{G}, or
+or of the form
+\tcode{R(*)(G, A...)~\opt{noexcept}}
+for a type \tcode{G}, or
 \item
 \tcode{F::operator()} is a static member function and
 \tcode{decltype(\&F::operator())} is of the form
diff --git a/source/utilities.tex b/source/utilities.tex
index 39ab1f815e..642efdf2c9 100644
--- a/source/utilities.tex
+++ b/source/utilities.tex
@@ -2905,13 +2905,13 @@
 it means that an object of type \tcode{T}, referred to as the optional object's \defnx{contained value}{contained value!\idxcode{optional}},
 is allocated within the storage of the optional object.
 Implementations are not permitted to use additional storage, such as dynamic memory, to allocate its contained value.
-The contained value shall be allocated in a region of the \tcode{optional<T>} storage suitably aligned for the type \tcode{T}.
 When an object of type \tcode{optional<T>} is contextually converted to \tcode{bool},
 the conversion returns \tcode{true} if the object contains a value;
 otherwise the conversion returns \tcode{false}.
 
 \pnum
-Member \tcode{val} is provided for exposition only. When an \tcode{optional<T>} object contains a value, \tcode{val} points to the contained value.
+When an \tcode{optional<T>} object contains a value,
+member \tcode{val} points to the contained value.
 
 \pnum
 \tcode{T} shall be a type
@@ -4635,8 +4635,6 @@
 \tcode{variant} object.
 Implementations are not permitted to use additional storage, such as dynamic
 memory, to allocate the contained value.
-The contained value shall be allocated in a region of the \tcode{variant}
-storage suitably aligned for all types in \tcode{Types}.
 
 \pnum
 All types in \tcode{Types} shall meet
@@ -6933,11 +6931,7 @@
 Implementations are not permitted to use additional storage,
 such as dynamic memory,
 to allocate the object of type \tcode{T} or the object of type \tcode{E}.
-These objects are allocated in a region of the \tcode{expected<T, E>} storage
-suitably aligned for the types \tcode{T} and \tcode{E}.
-Members \exposid{has_val}, \exposid{val}, and \exposid{unex}
-are provided for exposition only.
-\exposid{has_val} indicates whether the \tcode{expected<T, E>} object
+Member \exposid{has_val} indicates whether the \tcode{expected<T, E>} object
 contains an object of type \tcode{T}.
 
 \pnum
@@ -7977,6 +7971,21 @@
 };
 \end{codeblock}
 
+\pnum
+Any object of type \tcode{expected<T, E>} either
+represents a value of type \tcode{T}, or
+contains a value of type \tcode{E} within its own storage.
+Implementations are not permitted to use additional storage,
+such as dynamic memory, to allocate the object of type \tcode{E}.
+Member \exposid{has_val} indicates whether the \tcode{expected<T, E>} object
+represents a value of type \tcode{T}.
+
+\pnum
+A program that instantiates
+the definition of the template \tcode{expected<T, E>} with
+a type for the \tcode{E} parameter that
+is not a valid template argument for \tcode{unexpected} is ill-formed.
+
 \pnum
 \tcode{E} shall meet the requirements of
 \oldconcept{Destructible} (\tref{cpp17.destructible}).
@@ -8268,7 +8277,7 @@
 Otherwise, if \tcode{rhs.has_value()} is \tcode{true},
 destroys \exposid{unex} and sets \exposid{has_val} to \tcode{true}.
 \item
-Otherwise, equivalent to \tcode{\exposid{unex} = rhs.error()}.
+Otherwise, equivalent to \tcode{\exposid{unex} = std::move(rhs.error())}.
 \end{itemize}
 
 \pnum
@@ -11679,9 +11688,11 @@
 \begin{itemize}
 \item
 \tcode{F::operator()} is a non-static member function and
-\tcode{decltype(\brk{}\&F::operator())} is of the form
+\tcode{decltype(\brk{}\&F::operator())} is either of the form
 \tcode{R(G::*)(A...)}~\cv{}~\tcode{\opt{\&}~\opt{noexcept}}
-for a class type \tcode{G}, or
+or of the form
+\tcode{R(*)(G, A...)~\opt{noexcept}}
+for a type \tcode{G}, or
 \item
 \tcode{F::operator()} is a static member function and
 \tcode{decltype(\&F::operator())} is of the form
@@ -13822,9 +13833,7 @@
 a \fmtgrammarterm{width} or \fmtgrammarterm{precision},
 the value of the corresponding formatting argument is used in its place.
 If the corresponding formatting argument is not of integral type, or
-its value is
-negative for \fmtgrammarterm{precision} or
-non-positive for \fmtgrammarterm{width},
+its value is negative,
 an exception of type \tcode{format_error} is thrown.
 
 \pnum
@@ -14646,6 +14655,7 @@
 \begin{codeblock}
 template<> struct formatter<charT*, charT>;
 template<> struct formatter<const charT*, charT>;
+template<size_t N> struct formatter<charT[N], charT>;
 template<size_t N> struct formatter<const charT[N], charT>;
 template<class traits, class Allocator>
   struct formatter<basic_string<charT, traits, Allocator>, charT>;
@@ -15516,7 +15526,7 @@
   template<class T>
     constexpr T bit_floor(T x) noexcept;
   template<class T>
-    constexpr T bit_width(T x) noexcept;
+    constexpr int bit_width(T x) noexcept;
 
   // \ref{bit.rotate}, rotating
   template<class T>
@@ -15700,7 +15710,7 @@
 \indexlibraryglobal{bit_width}%
 \begin{itemdecl}
 template<class T>
-  constexpr T bit_width(T x) noexcept;
+  constexpr int bit_width(T x) noexcept;
 \end{itemdecl}
 
 \begin{itemdescr}
diff --git a/source/xrefdelta.tex b/source/xrefdelta.tex
index 9677de5fb1..8c6dd51293 100644
--- a/source/xrefdelta.tex
+++ b/source/xrefdelta.tex
@@ -99,5 +99,8 @@
 % P1467R9 Extended floating-point types and standard names
 \movedxref{complex.special}{complex.members}
 
+% LWG3659 Consider ATOMIC_FLAG_INIT undeprecation
+\removedxref{depr.atomics.flag}
+
 % Deprecated features.
 %\deprxref{old.label}  (if moved to depr.old.label, otherwise use \movedxref)