I would like to ask to not do this, as this is a breaking change and I have written code (outside Boost) that relies on BOOST_THROW_EXCEPTION and boost::exception. That is, I expect that an exception thrown by BOOST_THROW_EXCEPTION triggers `catch (boost::exception& e)` handler, where I may augment it with additional info before rethrowing.
By the way you can use Boost LEAF for this, it's more convenient and more efficient. Instead of: typedef boost::error_info<struct my_info_, int> my_info; void f() { try { g(); } catch( boost::exception & e ) { e << my_info(42); throw; } } You'd use: struct my_info { int value }; void f() { auto load = on_error( my_info{42} ); g(); } The above generally works with any exception, there is no need to derive from a special base type.