Definition SOL_SAFE_USERTYPE is 0, sol compilation fails about sol2 HOT 3 OPEN

In file included from <source>:4:
In file included from /opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/sol.hpp:54:
In file included from /opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/usertype.hpp:27:
In file included from /opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/usertype_core.hpp:37:
In file included from /opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/usertype_container_launch.hpp:28:
/opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/usertype_container.hpp:541:12: error: non-const lvalue reference to type 'span<...>' cannot bind to a temporary of type 'span<...>'
  541 |                                 return stack::unqualified_get<T>(L, 1);
      |                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/usertype_container.hpp:1212:17: note: in instantiation of member function 'sol::container_detail::usertype_container_default<std::span<std::basic_string<char>>>::get_src' requested here
 1212 |                                 auto& src = get_src(L);
      |                                             ^
/opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/usertype_container.hpp:1353:12: note: in instantiation of function template specialization 'sol::container_detail::usertype_container_default<std::span<std::basic_string<char>>>::pairs_associative<false>' requested here
 1353 |                                 return pairs_associative<false>(is_assoc(), L);
      |                                        ^
/opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/usertype_container_launch.hpp:125:16: note: in instantiation of member function 'sol::container_detail::usertype_container_default<std::span<std::basic_string<char>>>::pairs' requested here
  125 |                                 return uc::pairs(L);
      |                                            ^
/opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/usertype_container_launch.hpp:133:12: note: in instantiation of member function 'sol::container_detail::u_c_launch<std::span<std::basic_string<char>>>::real_pairs_traits' requested here
  133 |                                 return real_pairs_traits(container_detail::has_traits_pairs<uc>(), L);
      |                                        ^
/opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/usertype_container_launch.hpp:286:74: note: in instantiation of member function 'sol::container_detail::u_c_launch<std::span<std::basic_string<char>>>::real_pairs_call' requested here
  286 |                                 return detail::typed_static_trampoline<decltype(&real_pairs_call), (&real_pairs_call)>(L);
      |                                                                                                      ^
/opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/usertype_container_launch.hpp:335:46: note: (skipping 8 contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all)
  335 |                                                 { "__pairs", &meta_usertype_container::pairs_call },
      |                                                                                        ^
/opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/stack_core.hpp:948:19: note: in instantiation of function template specialization 'sol::stack::push<sol::detail::as_reference_tag, std::span<std::basic_string<char>> &, void>' requested here
  948 |                                 return stack::push<Tr>(L, std::forward<Arg>(arg), std::forward<Args>(args)...);
      |                                               ^
/opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/stack_core.hpp:955:25: note: in instantiation of function template specialization 'sol::stack::stack_detail::push_reference<std::span<std::basic_string<char>> &, std::span<std::basic_string<char>> &>' requested here
  955 |                         return stack_detail::push_reference<T>(L, std::forward<T>(t), std::forward<Args>(args)...);
      |                                              ^
/opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/stack_core.hpp:982:20: note: in instantiation of function template specialization 'sol::stack::push_reference<std::span<std::basic_string<char>> &>' requested here
  982 |                         int pushcount = push_reference(L, std::forward<T>(t));
      |                                         ^
/opt/compiler-explorer/libs/sol2/v3.2.1/include/sol/unsafe_function.hpp:169:27: note: in instantiation of function template specialization 'sol::stack::multi_push_reference<std::span<std::basic_string<char>> &>' requested here
  169 |                         int pushcount = stack::multi_push_reference(lua_state(), std::forward<Args>(args)...);
      |                                                ^
<source>:21:4: note: in instantiation of function template specialization 'sol::basic_function<sol::basic_reference<false>, false>::operator()<std::span<std::basic_string<char>> &>' requested here
   21 |         f1(sp);// compile error
      |           ^
3 warnings and 1 error generated.

return *stack::unqualified_get<T*>(L_, 1);