[Boost-bugs] [Boost C++ Libraries] #8463: function_output_iterator: MSVC warning C4512

Subject: [Boost-bugs] [Boost C++ Libraries] #8463: function_output_iterator: MSVC warning C4512
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2013-04-19 18:10:30

#8463: function_output_iterator: MSVC warning C4512
--------------------------------------------------------------------------+-
 Reporter:  Mike Cowperthwaite <michael.cowperthwaite@…>                  |        Type:  Bugs            
   Status:  new                                                           |   Milestone:  To Be Determined
Component:  None                                                          |     Version:  Boost 1.52.0    
 Severity:  Problem                                                       |    Keywords:                  
--------------------------------------------------------------------------+-
 In `boost/function_output_iterator` the struct
 `function_output_iterator::output_proxy` yields this warning: "assignment
 operator could not be generated."
 I see this primarily using signals2, where the iterator class is created
 using  `boost::signals2::detail::does_nothing`  as the iterator template
 argument.

 The warning is due to the proxy's const data member, and probably not
 dependent on the iterator template argument.

 The struct also has a templated operator= defined, but not of the sort
 that would work as a copy-assignment.

 Other libraries (fusion, spirit, statechart in particular) have
 implemented do-nothing assignment operators (or just declarations) to
 overcome similar symptoms.  If I do the same for this class in my local
 copy -- simply add a declaration for this particular signature:
 {{{
   private:
     output_proxy& operator=(output_proxy const &src);
 }}}
 the warning goes away; however, I can't be sure this doesn't break
 something.  It seems unlikely, as I can run code with the warning and my
 signals seem to work just fine.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/8463>
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