the result value of some built-in functions such as
<code>unsafe.Sizeof</code> applied to any value,
<code>cap</code> or <code>len</code> applied to
<a href="#Length_and_capacity">some expressions</a>,
<code>real</code> and <code>imag</code> applied to a complex constant
and <code>complex</code> applied to numeric constants.
The boolean truth values are represented by the predeclared constants