a type <code>T</code>, or it may refer
to a field or method <code>f</code> of a nested
<a href="#Struct_types">embedded field</a> of <code>T</code>.
The number of embedded fields traversed
to reach <code>f</code> is called its <i>depth</i> in <code>T</code>.
The depth of a field or method <code>f</code>
declared in <code>T</code> is zero.
The depth of a field or method <code>f</code> declared in