[Boost-bugs] [Boost C++ Libraries] #7391: phoenix::insert compile fails with libc++

Subject: [Boost-bugs] [Boost C++ Libraries] #7391: phoenix::insert compile fails with libc++
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-09-19 07:32:14

#7391: phoenix::insert compile fails with libc++
-------------------------------------+--------------------------------------
 Reporter:  Naomasa Matsubayashi     |       Owner:  theller
     Type:  Bugs                     |      Status:  new    
Milestone:  To Be Determined         |   Component:  phoenix
  Version:  Boost Development Trunk  |    Severity:  Problem
 Keywords:                           |  
-------------------------------------+--------------------------------------
 Following code produces a compile error with libc++.
 {{{
 #include <vector>
 #include <boost/phoenix.hpp>

 int main() {
   std::vector< int > hoge;
   std::vector< int > fuga;
   namespace phx = boost::phoenix;
   phx::insert( phx::placeholders::_1, phx::placeholders::_2, fuga.begin(),
 fuga.end() )( hoge, hoge.end() );
 }
 }}}
 That is because phoenix::insert expects the member function insert returns
 void when was is called with 3 arguments. That is correct in C++03 but not
 in C++11.( All insert overloads returns an iterator in C++11 [23.3.7.1] )

 Since libstdc++ returns void even if the code was compiled as C++11, the
 problem doesn't appear. But at least with libc++, it fails to compile and
 following error message is produced.
 {{{
       void function 'operator()' should not return a value [-Wreturn-type]
                 return c.insert(arg1, arg2, arg3);
                 ^      ~~~~~~~~~~~~~~~~~~~~~~~~~~
 }}}

 This patch fixed the problem on libc++.
 I think it needs more intelligent way to detect environments those insert
 always return a iterator. But I don't have any good idea on that :(
 {{{
 --- boost/phoenix/stl/container/container.hpp
 +++ boost/phoenix/stl/container/container.hpp
 @@ -425,6 +425,9 @@
                  choice_1;

                  typedef
 +#ifdef _LIBCPP_VERSION
 +                    iterator_of<C>
 +#else
                      boost::mpl::eval_if_c<
                          boost::mpl::and_<
                              boost::is_same<Arg3, mpl::void_>
 @@ -433,8 +436,8 @@
                        , iterator_of<C>
                        , boost::mpl::identity<void>
                      >
 +#endif
                  choice_2;
 -
              public:

                  typedef typename
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/7391>
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