`std::vector` of custom types crashes about sol2

[uyha]

so adding the following overloads makes it work, but I wonder why this is not done automatically?

template <typename Handler>
auto sol_lua_check(sol::types<sol::nested<A>>,
                                lua_State *L,
                                int index, 
                                Handler &&handler,
                                sol::stack::record &tracking) -> bool {
  return sol_lua_check<Handler>(sol::types<A>{}, L, index, handler, tracking);
}

auto sol_lua_get(sol::types<sol::nested<A>>,
                            lua_State *L,
                            int index,
                            sol::stack::record &tracking) -> A {
  return sol_lua_get(sol::types<A>{}, L, index, tracking);
}