Merge 2022-07 LWG Motion 1

P2618R0 C++ Standard Library Issues

Author: tkoeppe

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)}

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);

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}

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
   };
 }

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}
 

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)

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}