</p>

<ul>
<li>
	Both type parameters are identical.
</li>
<li>
	At most one of the type parameters has a known type argument.
	In this case, the type parameters are <i>joined</i>:
	they both stand for the same type argument.
	If neither type parameter has a known type argument yet,
	a future type argument inferred for one the type parameters
	is simultaneously inferred for both of them.
</li>
<li>