In the rewritten program, the other goroutine can observe <code>2</code>, which was previously impossible.
</p>

<p>
Not introducing data races also means not assuming that loops terminate.
For example, a compiler must in general not move the accesses to <code>*p</code> or <code>*q</code>
ahead of the loop in this program:
</p>

<pre>
n := 0
for e := list; e != nil; e = e.next {
	n++
}