all types in its type set must have the same underlying type, which must be a slice
or map type, or, if there are channel types, there must only be channel types, they
must all have the same element type, and the channel directions must not conflict.
</p>

<p>
Each of the size arguments <code>n</code> and <code>m</code> must be of <a href="#Numeric_types">integer type</a>,