[Boost-bugs] [Boost C++ Libraries] #3022: Automatic conversion from Y* to boost::shared_ptr<Y> with std::pair

Subject: [Boost-bugs] [Boost C++ Libraries] #3022: Automatic conversion from Y* to boost::shared_ptr<Y> with std::pair
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-05-13 14:28:15

#3022: Automatic conversion from Y* to boost::shared_ptr<Y> with std::pair
--------------------------------------------+-------------------------------
 Reporter:  koelsch_at_[hidden]                 |       Owner:  pdimov   
     Type:  Bugs                            |      Status:  new      
Milestone:                                  |   Component:  smart_ptr
  Version:  Boost 1.39.0                    |    Severity:  Problem  
 Keywords:  implicit conversion shared_ptr  |  
--------------------------------------------+-------------------------------
 The assignment of std::pair<X,Y*> to std::pair<X,boost::shared_ptr<Y> >
 compiles without warning and implicitly converts a Y* to a
 boost::shared_ptr<Y>. I guess this has to do with:

 template<class T> class shared_ptr
 {
 ...
 template<class Ap>
 typename boost::detail::sp_enable_if_auto_ptr< Ap, shared_ptr & >::type
 operator=( Ap r )
 ...
 };

 This behavior was witnessed under VC2005, VC2008, and gcc4.0.1.

 A minimal program demonstrating an evil consequence of this follows:

 int main()
 {
     int i = 2;
     boost::shared_ptr<int> j( new int );

     //boost::shared_ptr<int> k = &*j; // does not compile
     //std::pair<int,boost::shared_ptr<int> > v( i, &*j ); // does not
 compile
     std::pair<int,boost::shared_ptr<int> > v = std::make_pair( i, &*j );
 // However, this compiles
     // kabum
 }

 Regards,

    Tobias

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3022>
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