corresponding method types unify exactly,
	and the method set of one of the interfaces is a subset of
	the method set of the other interface.
</li>
<li>
	Only one type is an interface (but not a type parameter),
	corresponding methods of the two types unify per the element matching mode,
	and the method set of the interface is a subset of
	the method set of the other type.
</li>
<li>