id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
10439	Flyweight: now the constructor is explicit	akim Demaille <akim.demaille@…>	Joaquín M López Muñoz	"Hi,

The following piece of code used to work fine, but with 1.56, it now fails to compile with the two major free compilers.

Thanks!

{{{
$ cat /tmp/foo.cc
#include <string>
#include <boost/flyweight.hpp>

int main()
{
  boost::flyweight<std::string> f = {};
}
$ clang++-mp-3.5 -std=c++11 -I /opt/local/include foo.cc
foo.cc:6:33: error: chosen constructor is explicit in copy-initialization
  boost::flyweight<std::string> f = {};
                                ^   ~~
/opt/local/include/boost/flyweight/flyweight.hpp:195:14: note: constructor declared here
    explicit flyweight,
             ^
/opt/local/include/boost/flyweight/detail/perfect_fwd.hpp:79:27: note: expanded from macro 'BOOST_FLYWEIGHT_PERFECT_FWD'
template<typename... Args>name(Args&&... args) \
                          ^
1 error generated.
$ g++-mp-4.9 -std=c++11 -I /opt/local/include foo.cc
foo.cc: In function 'int main()':
foo.cc:6:38: error: converting to 'boost::flyweights::flyweight<std::basic_string<char> >' from initializer list would use explicit constructor 'boost::flyweights::flyweight<T, Arg1, Arg2, Arg3, Arg4, Arg5>::flyweight(Args&& ...) [with Args = {}; T = std::basic_string<char>; Arg1 = boost::parameter::void_; Arg2 = boost::parameter::void_; Arg3 = boost::parameter::void_; Arg4 = boost::parameter::void_; Arg5 = boost::parameter::void_]'
   boost::flyweight<std::string> f = {};
                                      ^
}}}"	Bugs	closed	To Be Determined	flyweight	Boost 1.56.0	Problem	fixed