id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
12121	Duplicate conflicting forward declaration of basic_string_ref	white@…	Andrey Semashev	"In Boost 1.61 Beta 1, a new error means to much forward declaration of basic_string_ref.

boost/log/utility/formatting_ostream.hpp:39:76: error: redefinition of default argument for 'class traits'
 template<typename charT, typename traits = std::char_traits<charT> > class basic_string_ref;

Its also declared in
boost/utility/string_ref_fwd.hpp
and
boost/utility/string_ref.hpp


Removing the fwd declaration in formatting_ostream.hpp:39 and all is working.

Boost 1.61.0 beta
gcc 5.3.0 (x86_64-win32-seh-rev0, Built by MinGW-W64 project)
"	Bugs	closed	To Be Determined	log	Boost 1.61.0	Problem	fixed