denoted by the predeclared constants <code>true</code>
and <code>false</code>. The predeclared boolean type is <code>bool</code>;
it is a <a href="#Type_definitions">defined type</a>.
</p>

<h3 id="Numeric_types">Numeric types</h3>

<p>
A <i>numeric type</i> represents sets of integer or floating-point values.
The predeclared architecture-independent numeric types are:
</p>

TypeList  = Type { "," Type } .
TypeLit   = ArrayType | StructType | PointerType | FunctionType | InterfaceType |
            SliceType | MapType | ChannelType .
</pre>

<p>
The language <a href="#Predeclared_identifiers">predeclares</a> certain type names.
Others are introduced with <a href="#Type_declarations">type declarations</a>
or <a href="#Type_parameter_declarations">type parameter lists</a>.

	getTypeIDs map[string]bool

	// incompleteStructs contains C structs that should be marked Incomplete.
	incompleteStructs map[string]bool

	// Predeclared types.
	bool                                   ast.Expr
	byte                                   ast.Expr // denotes padding
	int8, int16, int32, int64              ast.Expr

<h3 id="symbols">Symbols</h3>

<p>
Some symbols, such as <code>R1</code> or <code>LR</code>,
are predefined and refer to registers.
The exact set depends on the architecture.
</p>

<p>
There are four predeclared symbols that refer to pseudo-registers.
These are not real registers, but rather virtual registers maintained by
the toolchain, such as a frame pointer.
The set of pseudo-registers is the same for all architectures:
</p>

// not as the type of a variable.
type comparable interface{ comparable }

// iota is a predeclared identifier representing the untyped integer ordinal
// number of the current const specification in a (usually parenthesized)
// const declaration. It is zero-indexed.
const iota = 0 // Untyped int.

// nil is a predeclared identifier representing the zero value for a
// pointer, channel, func, interface, map, or slice type.

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

TEXT foo(SB), 0, $0
	RET
TEXT foo(SB), 0, $0 // ERROR "symbol foo redeclared"
	RET

GLOBL bar(SB), 0, $8
GLOBL bar(SB), 0, $8 // ERROR "symbol bar redeclared"

DATA bar+0(SB)/8, $0