What is the rationale for the expression class{}.refmem to be an lvalue expression

Question

I came to know that S{}.rval is an lvalue expression. I want to know the rationale behind considering it an lvalue expression.

Why are access to non-static member of reference type lvalue, even when the object is an rvalue?

struct S {
    int val;
    int& rval = val;
};
int main() {
    S{}.val; // xvalue
    S{}.rval; // lvalue
}

My expectation would have been that a reference to a "soon to die entity" would also be "soon to die". So I'd like to understand the rationale of the rule(s).

Answer 1

My expectation would have been that a reference to a "soon to die entity" would also be "soon to die".

That is not always true. The reference member may alias an object that will outlive the temporary S{}.

For example:

int i = 10;
struct S {
   
    int& rval = i; // rval refers to the global i
};
int main() {
    S{}.rval;     //the aliased object will outlive the object expression `S{}`
}