and the program is not valid.
</p>

<p>
Multiple variables on the left-hand side of a variable declaration initialized
by single (multi-valued) expression on the right-hand side are initialized
together: If any of the variables on the left-hand side is initialized, all
those variables are initialized in the same step.
</p>

<pre>
var x = a

The [Alias] type now has an [Rhs] method that returns the type on the
right-hand side of its declaration: given `type A = B`, the `Rhs` of A