Cannot use reflect_invoke metafunction to invoke a member function

[katzdm]

Given a reflection RMemFn, of a member function Cls::MemFn, a reflection RObj of a constant value Obj having type either Cls or Cls *, and reflections R_0, ..., R_n of constant values a_0, ..., a_n: if either obj.F(a_0, ..., a_n) or obj->F(a_0, ..., a_n) is a well-formed constant expression not returning void, then it would be nice to be able to obtain a reflection of the resulting value by calling

constexpr auto R = reflect_invoke(RMemFn, RObj, R_0, ..., R_n);

[BaLiKfromUA]

I am looking into it. Will try to deliver it.

Am I understand it right, that, probably, we are interested in introducing one more overload of reflect_invoke to separate case of non-static member function?

so instead of

constexpr auto R = reflect_invoke(RMemFn, RObj, R_0, ..., R_n);

it could look like this

constexpr auto R = reflect_invoke(RMemFn, RObj, {R_0, ..., R_n});

Similar to what you have in p2996r3 for template functions but without list as a second parameter

[katzdm]

Not quite - if the reflection represents a member function, then the first argument will be the object which the function is invoked on.

[BaLiKfromUA]

Implemented first version of disscussed functionality, please review when you have time.

I suspect that more validation should be added (e.g. check that method is not special) into my code but would like to disscuss it in scope of initial review.