Worse, there is no guarantee that the write to <code>done</code> will ever
be observed by <code>main</code>, since there are no synchronization
events between the two threads.  The loop in <code>main</code> is not
guaranteed to finish.
</p>

<p>
There are subtler variants on this theme, such as this program.
</p>

<pre>
type T struct {
	msg string
}

var g *T

func setup() {
	t := new(T)

</li>
</ul>

<p>
For example, given the declarations
</p>

<pre>
var (
	a = c + b  // == 9
	b = f()    // == 4
	c = f()    // == 5
	d = 3      // == 5 after initialization has finished
)

func f() int {
	d++
	return d
}
</pre>

<p>
the initialization order is <code>d</code>, <code>b</code>, <code>c</code>, <code>a</code>.

<code>string</code> takes the place of <code>P</code>.
And since <code>string</code> is identical to <code>string</code>,
this unification step succeeds as well.
Unification of the LHS and RHS of the equation is now finished.
Type inference succeeds because there is only one type equation,
no unification step failed, and the map is fully populated.
</p>

<p>
Unification uses a combination of <i>exact</i> and <i>loose</i>