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

int i = 0, *a = &i;

there is a sequence point between declarations, therefore no UB here. However take a note that it is a bad idea to declare/define variables that way. Any normal coding standard would tell you declare one variable per line.

a[i] = i;

The i is not changed in any way, therefore no UB here either.