Boost C++ Libraries: Ticket #5487: Trying to get from a variant results in error with vs10

attachment set

dd0t@… — Mon, 18 Apr 2011 22:50:47 GMT

attachment → nullptr_t_in_variant.cpp

Minimal example reproducing the problem

owner, component changed; cc set

Antony Polukhin — Tue, 10 Dec 2013 15:45:19 GMT

cc antoshkka@… added
owner changed from ebf to No-Maintainer
component variant → utility

Even a simpler example:

#include <boost/utility/addressof.hpp>
int main() {
    auto p = nullptr;
    boost::addressof(p);
}

Code above results gives the same error on MSVC11:

F:\boost_1_55_0\boost/utility/addressof.hpp(59): error C2666: 'boost::detail::addressof_impl<T>::f' : 2 overloads have similar conversions
1>          with
1>          [
1>              T=nullptr
1>          ]
1>          F:\boost_1_55_0\boost/utility/addressof.hpp(43): could be 'nullptr *boost::detail::addressof_impl<T>::f(T *,int)'
1>          with
1>          [
1>              T=nullptr
1>          ]
1>          F:\boost_1_55_0\boost/utility/addressof.hpp(37): or       'nullptr *boost::detail::addressof_impl<T>::f(T &,long)'
1>          with
1>          [
1>              T=nullptr
1>          ]
1>          while trying to match the argument list '(boost::detail::addr_impl_ref<T>, int)'
1>          with
1>          [
1>              T=nullptr
1>          ]
1>          main.cpp(5) : see reference to function template instantiation 'T *boost::addressof<nullptr>(T &)' being compiled
1>          with
1>          [
1>              T=nullptr
1>          ]

While GCC compiles successfully.

Marshall Clow — Tue, 10 Dec 2013 19:20:45 GMT

Also fails on a (fairly recent) clang:

$ clang++ -std=c++11 -stdlib=libc++ -I /Sources/boost/SVN/release/ boost.cpp
In file included from boost.cpp:1:
/Sources/boost/SVN/release/boost/utility/addressof.hpp:59:12: error: call to 'f'
      is ambiguous
    return boost::detail::addressof_impl<T>::f( boost::detail::addr_impl...
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
boost.cpp:5:5: note: in instantiation of function template specialization
      'boost::addressof<nullptr_t>' requested here
    boost::addressof(p);
    ^
/Sources/boost/SVN/release/boost/utility/addressof.hpp:37:23: note: candidate
      function
    static inline T * f( T & v, long )
                      ^
/Sources/boost/SVN/release/boost/utility/addressof.hpp:43:23: note: candidate
      function
    static inline T * f( T * v, int )
                      ^
1 error generated.

owner changed

Marshall Clow — Tue, 10 Dec 2013 19:22:19 GMT

owner changed from No-Maintainer to Peter Dimov

Peter Dimov — Wed, 11 Dec 2013 19:05:45 GMT

Should be fixed in https://github.com/boostorg/utility/commit/50eafe2027dfd45432fb7d97074e10cadb9bd899

status changed; resolution set

Peter Dimov — Wed, 11 Dec 2013 22:15:32 GMT

status new → closed
resolution → fixed