Does 'a[i] = i;' always result in well defined behaviour?

Question

There are several interesting questions raised here regarding undefined behaviour in C. One of them is (slightly modified)

Does the following piece of code r

Answer 1

I would like to point out one thing: a[i] = i does not always lead to well defined behaviour. The reason why the behaviour is well defined in the case specified, is because of the initial values i and a.

Let me elaborate:

int i = 1, *a = &i;   // Line 1, i initialized to anything other than 0
a[i] = i + 1;         // Line 2, all of a sudden we are in buffer over/underflow

For any other initial value of i we are accessing a different memory location from that of i itself, which produces undefined behaviour.