that is, either a variable, pointer indirection, or slice indexing
operation; or a field selector of an addressable struct operand;
or an array indexing operation of an addressable array.
As an exception to the addressability requirement, <code>x</code> may also be a
(possibly parenthesized)
<a href="#Composite_literals">composite literal</a>.
If the evaluation of <code>x</code> would cause a <a href="#Run_time_panics">run-time panic</a>,