https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103313
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #3) > Note this code was not valid as there is no way to deduce the template > arguments based on the default argument. Note I was slightly wrong here. it is deduced but to be empty because the default argument does not come into play until after the deduction. So the error message is saying can't convert from std::make_index_sequence<3> to index_sequence<>.
