Hi, Recently I tried to port my code to Boost.Spirit v2 and Boost.Phoenix v3. After including the following headers: #include <boost/phoenix/core.hpp> #include <boost/spirit/include/qi_core.hpp> I got the following error: In file included from ./boost/spirit/home/phoenix/core.hpp:13:0, from ./boost/spirit/include/phoenix_core.hpp:14, from ./boost/spirit/home/support/make_component.hpp:15, from ./boost/spirit/home/support/meta_compiler.hpp:20, from ./boost/spirit/home/qi/domain.hpp:15, from ./boost/spirit/home/qi/parser.hpp:15, from ./boost/spirit/include/qi_core.hpp:16, from libs/log/src/text_file_backend.cpp:51: ./boost/spirit/home/phoenix/core/actor.hpp:46:16: error: redefinition of ‘struct boost::phoenix::detail::error_expecting_arguments’ ./boost/phoenix/core/actor.hpp:41:16: error: previous definition of ‘struct boost::phoenix::detail::error_expecting_arguments’ ./boost/spirit/home/phoenix/core/actor.hpp:65:12: error: redefinition of ‘struct boost::phoenix::actor<Expr>’ ./boost/phoenix/core/actor.hpp:161:12: error: previous definition of ‘struct boost::phoenix::actor<Expr>’ I take it the problem is that Boost.Spirit always include Phoenix v2 which causes name clashes with v3. Is this a known problem? Shouldn't Boost.Spirit include Phoenix v3 headers instead? I can see v3 redirects includes to v2 if BOOST_PHOENIX_USE_V2_OVER_V3 macro is defined (BTW, there's an error in boost/phoenix/stl.hpp: BOOST_PHOENIX_USE_V2 macro is checked instead). This happens in the release branch.