test.cc: In function ‘int test()’: test.cc:12:15: error: could not convert ‘std::map<int, std::vector<double> >()’ from ‘map<[...],vector<double>>’ to ‘map<[...],vector<float>>’ map< [...], vector< [double != float]>> takes_mivf (map<int, vector<double> > ()); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~