Failed overload resolution during pack expansion - c++11

Question

while I was trying to make some adaptations in my code, I encountered a problem with pack expansion, where theoretically it should compile.
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(20,2): error C2672: 'ExpandArgs': no matching overloaded function found
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(17): message : see reference to function template instantiation 'void `anonymous-namespace'::ExpandArgs<const char(&)[9],>(boost::log::v2s_mt_nt6::record_ostream &,Arg)' being compiled
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(17): message : with
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(17): message : [
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(17): message : Arg=const char (&)[9]
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(17): message : ]
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(54): message : see reference to function template instantiation 'void `anonymous-namespace'::ExpandArgs<const char(&)[9],std::string&>(boost::log::v2s_mt_nt6::record_ostream &,Arg,std::string &)' being compiled
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(54): message : with
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(54): message : [
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(54): message : Arg=const char (&)[9]
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(54): message : ]
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(77): message : see reference to function template instantiation 'void CustomLogger::Log<boost::log::v2s_mt_nt6::sources::logger_mt,const char(&)[9],std::string&>(Logger &,const char (&)[9],std::string &)' being compiled
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(77): message : with
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(77): message : [
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(77): message : Logger=boost::log::v2s_mt_nt6::sources::logger_mt
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(77): message : ]
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(88): message : see reference to function template instantiation 'void sA::Log<const char(&)[9],std::string&>(const char (&)[9],std::string &)' being compiled
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(17,1): error C2780: 'void `anonymous-namespace'::ExpandArgs(boost::log::v2s_mt_nt6::record_ostream &,Arg &&,Args &&...)': expects 3 arguments - 1 provided
1>C:\Projects\PocTemplateOverloadingResolution\Source.cpp(16): message : see declaration of '`anonymous-namespace'::ExpandArgs'
Code: Link to code
I are using Visual Studio 2019 (v142)
SDK Version: 10.0.18362.0
Can anyone see the problem?

Answer 1

Can anyone see the problem?
Not sure (sorry: no experience with boost) but...
template< typename Arg, typename ...Args >
void ExpandArgs(boost::log::record_ostream& stream, Arg&& arg, Args&&... args)
{
ExpandArgs(stream, std::forward< Arg >(arg));
ExpandArgs(stream, std::forward<Args>(args)...); // SHOULD COMPILE, right?
//ExpandArgs(stream, "xpto", std::string("xpto"));
}
template< typename Arg >
void ExpandArgs(boost::log::record_ostream& stream, Arg&& arg)
{
stream << std::forward< Arg >(arg);
}
what about, when Args... is empty, in the "SHOULD COMPILE, right?" call?
ExpandArgs(stream, std::forward<Args>(args)...); // ???
The call become
ExpandArgs(stream);
but I don't see an ExpandArgs() function that receive only a stream argument.
I suppose you can add a terminal case as follows
void ExpandArgs (boost::log::record_ostream &)
{ }
to solve this problem.