[Bug libstdc++/85069] std::invoke_result returns a wrong type

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85069

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
P.S. std::result_of is implemented in terms of std::invoke_result, so they will
always give the same answer when asked the same question. I think your problem
is you're asking the wrong question.