c++ why non-static member function is a prvalue?

Question

I would like too know the rationale behind of and o->f being prvalue s, where o is an object, and f is a non-static member function.

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EDIT 1

My point is that putting it into a prvalue category seems to be tantamount to an ad hog decision as even though it is not an lvalue in its fullest, it's not yet a complete rvalue also.

1. g (a regular function) is not assignable, just like f (a non-static member function);
2. an address of both can somewhat be taken -- though pointer to member function is not required to contain an address, they are sorta semantically close operations. EDIT -- THAT IS NOTED IN COMMENTS THAT IT IS NOT AN ADDRESS OF of OR o->f THAT IS TAKEN
3. member function cannot init lvalue reference, but then it should init rvalue one, but can it?.

And that is odd -- consider point 1) above, only modifiable lvalue s are assignable by definition, so lvalue properties are not violated by this "non-assignability". But in 3), all prvalues shall be able to init rvalue references, but a member function can not, presumably.

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EDIT 2

I am particularly interested in something like a justification paper from committee people or something like this, showing why it is made this way.

I may be terribly wrong, but I may imagine a hypothetical set of rules that would allow of to follow all the behaviors of lvalue . We necessarily need a binding object only for the sake of function call, and technically there is still one definition of the member function in the programm. That seems to be a bit whimsical for me that we cannot trat pointer to non-static member functions exactly like regular function pointers except were call is attempted, where we should provide an argument for a implicit object parameter .

Answer 1

just my guess. In expression of() , f is not really a subobject of o , it effectively bind o and f together which can then be called.

which does something like

//-------------o.f----------------()
std::bind_front(&decltype(o)::f,o)()

except it preserve overloads and (thus) cannot be used in other way (like store in variable).