chan T           channel buffer capacity
</pre>

<p>
The capacity of a slice is the number of elements for which there is
space allocated in the underlying array.
At any time the following relationship holds:
</p>

<pre>
0 &lt;= len(s) &lt;= cap(s)
</pre>

<p>
The length of a <code>nil</code> slice, map or channel is 0.
The capacity of a <code>nil</code> slice or channel is 0.
</p>

Otherwise, type inference fails and the program is invalid.
</p>

<p>
Type inference uses the type relationships between pairs of types for inference:
For instance, a function argument must be <a href="#Assignability">assignable</a>
to its respective function parameter; this establishes a relationship between the
type of the argument and the type of the parameter.