Proposed resolution:

1. Modify the basic_regex synopsis in [re.regex] p. 3:

   namespace std {
     template <class charT,
               class traits = regex_traits<charT> >
     class basic_regex {
     public:
       ...
       basic_regex& operator=(const basic_regex&);
       basic_regex& operator=(basic_regex&&) noexcept;
       basic_regex& operator=(const charT* ptr);
       ...
     };
   }
   

2. Modify [re.regex.assign] p. 2:

   basic_regex& operator=(basic_regex&& e) noexcept;
   

   2 Effects: returns assign(std::move(e)).

[ 2011-02-24 Reflector discussion ]

Moved to Tentatively Ready after 7 votes.

N3149 replaced the "Throws: nothing" clause on basic_regex::assign(basic_regex&&) with the noexcept keyword. The effects of the move-assignment operator are defined in terms of the assign() function, so the "Throws: nothing" applied there too, and a noexcept-specification should be added there too.