LWG3204 sub_match::swap only swaps the base class

Author: burblebee

source/regex.tex

@@ -1867,6 +1867,8 @@
       int compare(const sub_match& s) const;
       int compare(const string_type& s) const;
       int compare(const value_type* s) const;
+
+      void swap(sub_match& s) noexcept(@\seebelow@);
     };
 }
 \end{codeblock}
@@ -1952,6 +1954,31 @@
 \tcode{str().compare(s)}.
 \end{itemdescr}
 
+\indexlibrarymember{sub_match}{swap}%
+\begin{itemdecl}
+void swap(sub_match& s) noexcept(@\seebelow@);
+\end{itemdecl}
+
+\begin{itemdescr}
+\pnum
+\expects
+\tcode{BidirectionalIterator} meets
+the \oldconcept{Swappable} requirements\iref{swappable.requirements}.
+
+\pnum
+\effects
+Equivalent to:
+\begin{codeblock}
+this->pair<BidirectionalIterator, BidirectionalIterator>::swap(s);
+std::swap(matched, s.matched);
+\end{codeblock}
+
+\pnum
+\remarks
+The exception specification is equivalent to
+\tcode{is_nothrow_swappable_v<BidirectionalIter\-ator>}.
+\end{itemdescr}
+
 \rSec2[re.submatch.op]{Non-member operators}
 
 \pnum