LWG3067 recursive_directory_iterator::pop must invalidate

Author: jensmaurer

source/iostreams.tex

@@ -14337,6 +14337,11 @@
   Otherwise, cease iteration of the directory currently being
   iterated over, and continue iteration over the parent directory.
 
+\pnum
+\postconditions Any copies of the previous value of \tcode{*this}
+are no longer required
+either to be dereferenceable or to be in the domain of \tcode{==}.
+
 \pnum
 \throws As specified in~\ref{fs.err.report}.
 \end{itemdescr}