miso1289 / more_concepts Goto Github PK

I'm calling a constrained function from within a const member function, so the container is being marked const, and subsequently fails the concept check because a const vector is apparently not a container (because it's not moveable).

Ignore - this turns out to be misleading diagnostics, the actual problem was I was passing the const container to a non-const ref, however it was showing up as a concept fail.

base_concepts line 51 fails to compile with "unexpanded parameter pack":

    requires(Signatures& ... signatures)
    {
        ([] <typename Ret, typename... Args>(auto(&)(Args...) -> Ret)
        requires std::is_invocable_r_v<Ret, Fn, Args>
        {}(signatures), ...);
    };

It should be this (like the same thing at line 64):

 requires std::is_invocable_r_v<Ret, Fn, Args...>