id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc 8313,const definition of boost::none,anonymous,Fernando Cacciola,"boost provides an object named boost::none of type boost::none_t. it originally stems from Boost.Optional, but since it is in the root directory, boost/none.hpp, I guess it is there for other uses as well. I tried to use it in the following way, which fails, because of the definition of boost::none: template struct A{ A(T &a,T2 &b=none); }; boost::none is an object defined to be const, so it is not accepted as a non-const reference. I don't see a reason why it has to be const. its value is never used anyway. I'll probably have to use boost::enable_if instead, to enable a ""unary"" constructor if and only if T2 == boost::none_t ",Bugs,closed,To Be Determined,optional,Boost 1.52.0,Problem,wontfix,,