then in the original program, the other goroutine can only observe any prior value of <code>*p</code> and <code>1</code>.
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>

<a href="#Close"><code>close</code></a>.
The multi-valued assignment form of the
<a href="#Receive_operator">receive operator</a>
reports whether a received value was sent before
the channel was closed.
</p>

<p>
A single channel may be used in
<a href="#Send_statements">send statements</a>,
<a href="#Receive_operator">receive operations</a>,
and calls to the built-in functions

<a href="#Close"><code>close</code></a>.
The multi-valued assignment form of the
<a href="#Receive_operator">receive operator</a>
reports whether a received value was sent before
the channel was closed.
</p>

<p>
A single channel may be used in
<a href="#Send_statements">send statements</a>,
<a href="#Receive_operator">receive operations</a>,
and calls to the built-in functions