<code>core(C)</code> and <code>A</code> must unify loosely.
	If <code>P</code> does not have a known type argument
	and <code>C</code> contains exactly one type term <code>T</code>
	that is not an underlying (tilde) type, unification adds the
	mapping <code>P ➞ T</code> to the map.
</li>
<li>
	If <code>C</code> does not have a core type
	and <code>P</code> has a known type argument <code>A</code>,