I'm not sure if it's a compiler bug or PR bug, but ascii_types is invalid here when compiled with GCC 9.3.0.
==48759== Thread 22 b-httpworker.3:
==48759== Invalid read of size 8
==48759== at 0x4BC68C: __gnu_cxx::__normal_iterator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::fun
ction<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > (COutPoint const&, Coin const&)> > const*, std::vector<std::pair<std
::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::function<std::__cxx11::basic_string<char, std::char_traits<char>, std::
allocator<char> > (COutPoint const&, Coin const&)> >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<cha
r> >, std::function<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > (COutPoint const&, Coin const&)> > > > >::__normal_ite
rator(std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::function<std::__cxx11::basic_string<char, std::char_
traits<char>, std::allocator<char> > (COutPoint const&, Coin const&)> > const* const&) (stl_iterator.h:807)
==48759== by 0x4BC637: std::vector<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::function<std::__cxx1
1::basic_string<char, std::char_traits<char>, std::allocator<char> > (COutPoint const&, Coin const&)> >, std::allocator<std::pair<std::__cxx11::basic_stri
ng<char, std::char_traits<char>, std::allocator<char> >, std::function<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > (CO
utPoint const&, Coin const&)> > > >::begin() const (stl_vector.h:818)
==48759== by 0x4BA12F: decltype (({parm#1}.begin)()) std::begin<std::vector<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::all
ocator<char> >, std::function<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > (COutPoint const&, Coin const&)> >, std::all
ocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::function<std::__cxx11::basic_string<char, std::char
_traits<char>, std::allocator<char> > (COutPoint const&, Coin const&)> > > > >(std::vector<std::pair<std::__cxx11::basic_string<char, std::char_traits<cha
r>, std::allocator<char> >, std::function<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > (COutPoint const&, Coin const&)>
>, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::function<std::__cxx11::basic_string<cha
r, std::char_traits<char>, std::allocator<char> > (COutPoint const&, Coin const&)> > > > const&) (range_access.h:59)
==48759== by 0x48EC97: dumptxoutset()::$_37::operator()(RPCHelpMan const&, JSONRPCRequest const&) const (blockchain.cpp:2692)