Can array members be initialized self-referentially?

Consider the following code in which we initialize part of D based on another part of D:

struct c {
    c() : D{rand(), D[0]} {}
    int D[2];
};

int main() {
    c C;
    assert(C.D[0] == C.D[1]);
}

Is the above program well-defined? Can we safely use one part of the same array to initialize another part of it?