an entry for each type parameter.
</p>

<p>
For example, given the type equation with the bound type parameter
<code>P</code>
</p>

<pre>
	[10]struct{ elem P, list []P } ≡<sub>A</sub> [10]struct{ elem string; list []string }
</pre>

<p>
type inference starts with an empty map.
Unification first compares the top-level structure of the LHS and RHS
types.