https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120465
--- Comment #1 from Eligor Kadaf <eligorkadaf at gmail dot com> --- The value_type seems to be as expected: https://godbolt.org/z/MWs531orx However the example in comment above shall compile, yet it doesn't. Fun fact is that if we change const auto& pair to const std::pair<std::string, int>& pair it compiles.