We should be able to simplify the rules for comparable or delegate some of them
elsewhere since we have a section that clearly defines how interfaces implement
other interfaces based on their type sets. But this should get us going for now.
-->

<p>
The <a href="#Predeclared_identifiers">predeclared</a>
<a href="#Interface_types">interface type</a> <code>comparable</code>
denotes the set of all non-interface types that are