FieldName     = identifier .
Element       = Expression | LiteralValue .
</pre>

<p>
The LiteralType's underlying type must be a struct, array, slice, or map type
(the grammar enforces this constraint except when the type is given
as a TypeName).
The types of the elements and keys must be <a href="#Assignability">assignable</a>
to the respective field, element, and key types of the literal type;

(The meaning of the offset—offset from the frame pointer—distinct
from its use with <code>SB</code>, where it is an offset from the symbol.)
The assembler enforces this convention, rejecting plain <code>0(FP)</code> and <code>8(FP)</code>.
The actual name is semantically irrelevant but should be used to document
the argument's name.
It is worth stressing that <code>FP</code> is always a

FieldName     = identifier .
Element       = Expression | LiteralValue .
</pre>

<p>
The LiteralType's <a href="#Core_types">core type</a> <code>T</code>
must be a struct, array, slice, or map type
(the syntax enforces this constraint except when the type is given
as a TypeName).
The types of the elements and keys must be <a href="#Assignability">assignable</a>
to the respective field, element, and key types of type <code>T</code>;