Yes I think you're right Bruno, currently it should fail because the above line must be compiled and during the compilation MPL_ASSERT should fail. Of course as long as BOOST_GEOMETRY_IMPLEMENTATION_STATUS_BUILD is not defined as true.

Furthermore, the tool for checking if specifically distance() is implemented for some Geometries probably shouldn't be placed in util/is_implemented.hpp and have such general name as is_implemented<>. Or am I missing something?