type in <code>V</code>'s type set can be converted to each type in <code>T</code>'s
type set.
</li>
<li>
Only <code>V</code> is a type parameter and a value of each
type in <code>V</code>'s type set can be converted to <code>T</code>.
</li>
<li>
Only <code>T</code> is a type parameter and <code>x</code> can be converted to each
type in <code>T</code>'s type set.
</li>