LWG3320 span::cbegin/cend methods produce different results than std::[ranges::]cbegin/cend

Dawn Perchik · zygoloid · commit 6faa9cf651ec · 2020-02-26T17:47:45.000-08:00
Also fixes NB PL 247 (C++20 CD).
diff --git a/source/containers.tex b/source/containers.tex
@@ -10568,9 +10568,7 @@
     using reference = element_type&;
     using const_reference = const element_type&;
     using iterator = @\impdefx{type of \tcode{span::iterator}}@;        // see \ref{span.iterators}
-    using const_iterator = @\impdefx{type of \tcode{span::const_iterator}}@;
     using reverse_iterator = std::reverse_iterator<iterator>;
-    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
     static constexpr size_type extent = Extent;
 
     // \ref{span.cons}, constructors, copy, and assignment
@@ -10622,12 +10620,8 @@
     // \ref{span.iterators}, iterator support
     constexpr iterator begin() const noexcept;
     constexpr iterator end() const noexcept;
-    constexpr const_iterator cbegin() const noexcept;
-    constexpr const_iterator cend() const noexcept;
     constexpr reverse_iterator rbegin() const noexcept;
     constexpr reverse_iterator rend() const noexcept;
-    constexpr const_reverse_iterator crbegin() const noexcept;
-    constexpr const_reverse_iterator crend() const noexcept;
 
   private:
     pointer data_;              // \expos
@@ -11119,23 +11113,21 @@
 \rSec3[span.iterators]{Iterator support}
 
 \indexlibrarymember{iterator}{span}%
-\indexlibrarymember{const_iterator}{span}%
 \begin{itemdecl}
 using iterator = @\impdefx{type of \tcode{span::iterator}}@;
-using const_iterator = @\impdefx{type of \tcode{span::const_iterator}}@;
 \end{itemdecl}
 
 \begin{itemdescr}
 \pnum
-The types
-model \libconcept{contiguous_iterator}\iref{iterator.concept.contiguous},
-meet the \oldconcept{RandomAccessIterator}
+The type
+models \libconcept{contiguous_iterator}\iref{iterator.concept.contiguous},
+meets the \oldconcept{RandomAccessIterator}
 requirements\iref{random.access.iterators},
 and
-meet the requirements for
+meets the requirements for
 constexpr iterators\iref{iterator.requirements.general}.
 All requirements on container iterators\iref{container.requirements} apply to
-\tcode{span::iterator} and \tcode{span::const_iterator} as well.
+\tcode{span::iterator} as well.
 \end{itemdescr}
 
 \indexlibrarymember{span}{begin}%
@@ -11184,52 +11176,6 @@
 Equivalent to: \tcode{return reverse_iterator(begin());}
 \end{itemdescr}
 
-\indexlibrarymember{span}{cbegin}%
-\begin{itemdecl}
-constexpr const_iterator cbegin() const noexcept;
-\end{itemdecl}
-
-\begin{itemdescr}
-\pnum
-\returns
-A constant iterator referring to the first element in the span.
-If \tcode{empty()} is \tcode{true}, then it returns the same value
-as \tcode{cend()}.
-\end{itemdescr}
-
-\indexlibrarymember{span}{cend}%
-\begin{itemdecl}
-constexpr const_iterator cend() const noexcept;
-\end{itemdecl}
-
-\begin{itemdescr}
-\pnum
-\returns
-A constant iterator which is the past-the-end value.
-\end{itemdescr}
-
-\indexlibrarymember{span}{crbegin}%
-\begin{itemdecl}
-constexpr const_reverse_iterator crbegin() const noexcept;
-\end{itemdecl}
-
-\begin{itemdescr}
-\pnum
-\effects
-Equivalent to: \tcode{return const_reverse_iterator(cend());}
-\end{itemdescr}
-
-\indexlibrarymember{span}{crend}%
-\begin{itemdecl}
-constexpr const_reverse_iterator crend() const noexcept;
-\end{itemdecl}
-
-\begin{itemdescr}
-\pnum
-\effects
-Equivalent to: \tcode{return const_reverse_iterator(cbegin());}
-\end{itemdescr}
-
 
 \rSec3[span.objectrep]{Views of object representation}
 
