boost::mixin::bad_mutation_source
// In header: <boost/mixin/exception.hpp> class bad_mutation_source : public boost::mixin::exception { };
Thrown when an attempt is made to mutate an object whose type doesn't correspond to the expected source type of the mutation (the one to mutate from).
The most likely cause is when using a same_type_mutator on objects that are not of the same type