tokens-all.txt

Earlier	jjr	o
version	nn	o
For	in	o
the	dt	o
pre-Go1.18	nn	o
specification	nn	o
without	in	o
generics	nns	o
support	vb	o
see	vbp	o
The	dt	o
Go	nnp	o
Programming	nnp	o
Language	nnp	o
Specification	nnp	o
.	.	o
[	nn	o
For	in	o
reviewers	nns	o
:	:	o
Sections	nns	o
where	wrb	o
we	prp	o
know	vbp	o
of	in	o
missing	jj	o
prose	nn	o
are	vbp	o
marked	vbn	o
like	in	o
this	dt	o
.	.	o
The	dt	o
markers	nns	o
will	md	o
be	vb	o
removed	vbn	o
before	in	o
the	dt	o
release	nn	o
.	.	o
]	jj	o
Introduction	nn	o
This	dt	o
is	vbz	o
a	dt	o
reference	nn	o
manual	nn	o
for	in	o
the	dt	o
Go	nnp	o
programming	nn	o
language	nn	o
.	.	o
For	in	o
more	jjr	o
information	nn	o
and	cc	o
other	jj	o
documents	nns	o
,	,	o
see	vbp	o
golang.org	nn	o
.	.	o
Go	nnp	o
is	vbz	o
a	dt	o
general-purpose	jj	o
language	nn	o
designed	vbn	o
with	in	o
systems	nns	o
programming	nn	o
in	in	o
mind	nn	o
.	.	o
It	prp	o
is	vbz	o
strongly	rb	o
typed	jj	o
and	cc	o
garbage-collected	jj	o
and	cc	o
has	vbz	o
explicit	jj	o
support	vb	o
for	in	o
concurrent	jj	o
programming	nn	o
.	.	o
Programs	nns	o
are	vbp	o
constructed	vbn	o
from	in	o
packages	nns	o
,	,	o
whose	wp$	o
properties	nns	o
allow	vbp	o
efficient	jj	o
management	nn	o
of	in	o
dependencies	nns	o
.	.	o
The	dt	o
grammar	nn	o
is	vbz	o
compact	jj	o
and	cc	o
simple	nn	o
to	to	o
parse	vb	o
,	,	o
allowing	vbg	o
for	in	o
easy	jj	o
analysis	nn	o
by	in	o
automatic	jj	o
tools	nns	o
such	jj	o
as	in	o
integrated	jj	o
development	nn	o
environments	nns	o
.	.	o
Notation	nnp	o
The	dt	o
syntax	nn	o
is	vbz	o
specified	vbn	o
using	vbg	o
Extended	jj	o
Backus-Naur	jj	o
Form	nnp	o
(	(	o
EBNF	nnp	b-gpe
)	)	o
:	:	o
Production	nn	o
=	nnp	o
production_name	nn	o
"	nnp	o
=	nnp	o
"	nnp	o
[	nnp	o
Expression	nn	o
]	nnp	o
"	nnp	o
.	.	o
"	nn	o
.	.	o
Expression	nn	o
=	nnp	o
Alternative	jj	o
{	(	o
"	nnp	o
|	nnp	o
"	nnp	o
Alternative	jj	o
}	)	o
.	.	o
Alternative	jj	o
=	nnp	o
Term	nnp	b-person
{	(	o
Term	nnp	b-person
}	)	o
.	.	o
Term	nnp	b-person
=	nnp	o
production_name	nn	o
|	vbp	o
token	nn	o
[	nnp	o
"	nnp	o
…	nnp	o
"	nnp	o
token	nn	o
]	nnp	o
|	vbp	o
Group	nnp	b-person
|	vbp	o
Option	nnp	b-person
|	vbp	o
Repetition	nnp	o
.	.	o
Group	nnp	b-person
=	nnp	o
"	nnp	o
(	(	o
"	jj	o
Expression	nn	o
"	nnp	o
)	)	o
"	nn	o
.	.	o
Option	nnp	b-person
=	nnp	o
"	nnp	o
[	nnp	o
"	nnp	o
Expression	nn	o
"	nnp	o
]	nnp	o
"	nnp	o
.	.	o
Repetition	nnp	o
=	nnp	o
"	nnp	o
{	(	o
"	jj	o
Expression	nn	o
"	nnp	o
}	)	o
"	nnp	o
.	.	o
Productions	nns	o
are	vbp	o
expressions	nns	o
constructed	vbn	o
from	in	o
terms	nns	o
and	cc	o
the	dt	o
following	vbg	o
operators	nns	o
,	,	o
in	in	o
increasing	vbg	o
precedence	nn	o
:	:	o
|	vbp	o
alternation	nn	o
(	(	o
)	)	o
grouping	vbg	o
[	jj	o
]	nn	o
option	nn	o
(	(	o
0	-none-	o
or	cc	o
1	cd	o
times	nns	o
)	)	o
{}	vbp	o
repetition	nn	o
(	(	o
0	-none-	o
to	to	o
n	in	o
times	nns	o
)	)	o
Lower-case	nnp	o
production	nn	o
names	vbz	o
are	vbp	o
used	vbn	o
to	to	o
identify	vb	o
lexical	jj	o
tokens	nns	o
.	.	o
Non-terminals	nns	o
are	vbp	o
in	in	o
CamelCase	nnp	b-gpe
.	.	o
Lexical	jj	o
tokens	nns	o
are	vbp	o
enclosed	vbn	o
in	in	o
double	jj	o
quotes	nns	o
or	cc	o
back	rb	o
quotes	nns	o
.	.	o
The	dt	o
form	nn	o
represents	vbz	o
the	dt	o
set	nn	o
of	in	o
characters	nns	o
from	in	o
through	in	o
as	in	o
alternatives	nns	o
.	.	o
The	dt	o
horizontal	jj	o
ellipsis	nn	o
is	vbz	o
also	rb	o
used	vbn	o
elsewhere	rb	o
in	in	o
the	dt	o
spec	nn	o
to	to	o
informally	rb	o
denote	vbp	o
various	jj	o
enumerations	nns	o
or	cc	o
code	nn	o
snippets	nns	o
that	wdt	o
are	vbp	o
not	rb	o
further	jj	o
specified	vbn	o
.	.	o
The	dt	o
character	nn	o
(	(	o
as	in	o
opposed	vbn	o
to	to	o
the	dt	o
three	cd	o
characters	nns	o
)	)	o
is	vbz	o
not	rb	o
a	dt	o
token	nn	o
of	in	o
the	dt	o
Go	nnp	o
language	nn	o
.	.	o
Source	nnp	b-gpe
code	nn	o
representation	nn	o
Source	nnp	b-gpe
code	nn	o
is	vbz	o
Unicode	nnp	b-gpe
text	nn	o
encoded	vbn	o
in	in	o
UTF-8	nnp	b-gpe
.	.	o
The	dt	o
text	nn	o
is	vbz	o
not	rb	o
canonicalized	vbn	o
,	,	o
so	rb	o
a	dt	o
single	jj	o
accented	jj	o
code	nn	o
point	nn	o
is	vbz	o
distinct	jj	o
from	in	o
the	dt	o
same	jj	o
character	nn	o
constructed	vbn	o
from	in	o
combining	vbg	o
an	dt	o
accent	nn	o
and	cc	o
a	dt	o
letter	nn	o
;	:	o
those	dt	o
are	vbp	o
treated	vbn	o
as	in	o
two	cd	o
code	nn	o
points	nns	o
.	.	o
For	in	o
simplicity	nn	o
,	,	o
this	dt	o
document	nn	o
will	md	o
use	vbp	o
the	dt	o
unqualified	jj	o
term	nn	o
character	nn	o
to	to	o
refer	vb	o
to	to	o
a	dt	o
Unicode	nnp	b-gpe
code	nn	o
point	nn	o
in	in	o
the	dt	o
source	nn	o
text	nn	o
.	.	o
Each	dt	o
code	nn	o
point	nn	o
is	vbz	o
distinct	jj	o
;	:	o
for	in	o
instance	nn	o
,	,	o
upper	jj	o
and	cc	o
lower	jjr	o
case	nn	o
letters	nns	o
are	vbp	o
different	jj	o
characters	nns	o
.	.	o
Implementation	nnp	o
restriction	nn	o
:	:	o
For	in	o
compatibility	nn	o
with	in	o
other	jj	o
tools	nns	o
,	,	o
a	dt	o
compiler	nn	o
may	md	o
disallow	vb	o
the	dt	o
NUL	nnp	b-gpe
character	nn	o
(	(	o
U+0000	nnp	b-gpe
)	)	o
in	in	o
the	dt	o
source	nn	o
text	nn	o
.	.	o
Implementation	nnp	o
restriction	nn	o
:	:	o
For	in	o
compatibility	nn	o
with	in	o
other	jj	o
tools	nns	o
,	,	o
a	dt	o
compiler	nn	o
may	md	o
ignore	vb	o
a	dt	o
UTF-8-encoded	jj	o
byte	nn	o
order	nn	o
mark	nn	o
(	(	o
U+FEFF	nnp	b-gpe
)	)	o
if	in	o
it	prp	o
is	vbz	o
the	dt	o
first	jj	o
Unicode	nnp	b-gpe
code	nn	o
point	nn	o
in	in	o
the	dt	o
source	nn	o
text	nn	o
.	.	o
A	dt	o
byte	nn	o
order	nn	o
mark	nn	o
may	md	o
be	vb	o
disallowed	vbn	o
anywhere	rb	o
else	rb	o
in	in	o
the	dt	o
source	nn	o
.	.	o
Characters	nnps	o
The	dt	o
following	vbg	o
terms	nns	o
are	vbp	o
used	vbn	o
to	to	o
denote	vbp	o
specific	jj	o
Unicode	nnp	b-gpe
character	nn	o
classes	nns	o
:	:	o
In	in	o
The	dt	o
Unicode	nnp	b-gpe
Standard	nnp	o
8.0	cd	o
,	,	o
Section	nn	o
4.5	cd	o
"	nnp	o
General	nnp	o
Category	nnp	o
"	nnp	o
defines	vbz	o
a	dt	o
set	nn	o
of	in	o
character	nn	o
categories	nns	o
.	.	o
Go	nnp	o
treats	in	o
all	pdt	o
characters	nns	o
in	in	o
any	dt	o
of	in	o
the	dt	o
Letter	nnp	o
categories	nns	o
Lu	nnp	o
,	,	o
Ll	nnp	b-gpe
,	,	o
Lt	nnp	b-gpe
,	,	o
Lm	nnp	b-gpe
,	,	o
or	cc	o
Lo	nnp	o
as	in	o
Unicode	nnp	b-gpe
letters	nns	o
,	,	o
and	cc	o
those	dt	o
in	in	o
the	dt	o
Number	nnp	o
category	nn	o
Nd	nnp	o
as	in	o
Unicode	nnp	b-gpe
digits	nns	o
.	.	o
Letters	nns	o
and	cc	o
digits	nns	o
The	dt	o
underscore	jj	o
character	nn	o
(	(	o
U+005F	nnp	b-gpe
)	)	o
is	vbz	o
considered	vbn	o
a	dt	o
letter	nn	o
.	.	o
Lexical	jj	o
elements	nns	o
Comments	nns	o
Comments	nns	o
serve	vbp	o
as	in	o
program	nn	o
documentation	nn	o
.	.	o
There	ex	o
are	vbp	o
two	cd	o
forms	nns	o
:	:	o
Line	nnp	o
comments	nns	o
start	vb	o
with	in	o
the	dt	o
character	nn	o
sequence	nn	o
and	cc	o
stop	vb	o
at	in	o
the	dt	o
end	nn	o
of	in	o
the	dt	o
line	nn	o
.	.	o
General	jj	o
comments	nns	o
start	vb	o
with	in	o
the	dt	o
character	nn	o
sequence	nn	o
and	cc	o
stop	vb	o
with	in	o
the	dt	o
first	jj	o
subsequent	jj	o
character	nn	o
sequence	nn	o
.	.	o
A	dt	o
comment	nn	o
cannot	vbp	o
start	vb	o
inside	in	o
a	dt	o
rune	nns	o
or	cc	o
string	vbg	o
literal	jj	o
,	,	o
or	cc	o
inside	in	o
a	dt	o
comment	nn	o
.	.	o
A	dt	o
general	jj	o
comment	nn	o
containing	vbg	o
no	dt	o
newlines	nns	o
acts	vbz	o
like	in	o
a	dt	o
space	nn	o
.	.	o
Any	dt	o
other	jj	o
comment	nn	o
acts	vbz	o
like	in	o
a	dt	o
newline	nn	o
.	.	o
Tokens	jj	b-gpe
Tokens	jj	b-gpe
form	nn	o
the	dt	o
vocabulary	nn	o
of	in	o
the	dt	o
Go	nnp	o
language	nn	o
.	.	o
There	ex	o
are	vbp	o
four	cd	o
classes	nns	o
:	:	o
identifiers	nns	o
,	,	o
keywords	nns	o
,	,	o
operators	nns	o
and	cc	o
punctuation	nn	o
,	,	o
and	cc	o
literals	nns	o
.	.	o
White	nnp	b-person
space	nn	o
,	,	o
formed	vbn	o
from	in	o
spaces	nns	o
(	(	o
U+0020	nnp	b-gpe
)	)	o
,	,	o
horizontal	jj	o
tabs	nn	o
(	(	o
U+0009	nnp	b-gpe
)	)	o
,	,	o
carriage	nn	o
returns	nns	o
(	(	o
U+000D	nnp	b-gpe
)	)	o
,	,	o
and	cc	o
newlines	nns	o
(	(	o
U+000A	nnp	b-gpe
)	)	o
,	,	o
is	vbz	o
ignored	vbn	o
except	vb	o
as	in	o
it	prp	o
separates	vbz	o
tokens	nns	o
that	wdt	o
would	md	o
otherwise	rb	o
combine	vb	o
into	in	o
a	dt	o
single	jj	o
token	nn	o
.	.	o
Also	rb	o
,	,	o
a	dt	o
newline	nn	o
or	cc	o
end	nn	o
of	in	o
file	nn	o
may	md	o
trigger	vbp	o
the	dt	o
insertion	nn	o
of	in	o
a	dt	o
semicolon	nn	o
.	.	o
While	in	o
breaking	vbg	o
the	dt	o
input	nn	o
into	in	o
tokens	nns	o
,	,	o
the	dt	o
next	jj	o
token	nn	o
is	vbz	o
the	dt	o
longest	jjs	o
sequence	nn	o
of	in	o
characters	nns	o
that	wdt	o
form	nn	o
a	dt	o
valid	jj	o
token	nn	o
.	.	o
Semicolons	nnps	o
The	dt	o
formal	jj	o
grammar	nn	o
uses	nns	o
semicolons	nns	o
as	in	o
terminators	nns	o
in	in	o
a	dt	o
number	nn	o
of	in	o
productions	nns	o
.	.	o
Go	nnp	o
programs	nns	o
may	md	o
omit	vb	o
most	jjs	o
of	in	o
these	dt	o
semicolons	nns	o
using	vbg	o
the	dt	o
following	vbg	o
two	cd	o
rules	nns	o
:	:	o
When	wrb	o
the	dt	o
input	nn	o
is	vbz	o
broken	vbn	o
into	in	o
tokens	nns	o
,	,	o
a	dt	o
semicolon	nn	o
is	vbz	o
automatically	rb	o
inserted	vbn	o
into	in	o
the	dt	o
token	nn	o
stream	nn	o
immediately	rb	o
after	in	o
a	dt	o
line	nn	o
's	pos	o
final	jj	o
token	nn	o
if	in	o
that	wdt	o
token	nn	o
is	vbz	o
an	dt	o
identifier	nn	o
an	dt	o
integer	nn	o
,	,	o
floating-point	jj	o
,	,	o
imaginary	jj	o
,	,	o
rune	nn	o
,	,	o
or	cc	o
string	vbg	o
literal	nn	o
one	nn	o
of	in	o
the	dt	o
keywords	nns	o
,	,	o
,	,	o
,	,	o
or	cc	o
one	nn	o
of	in	o
the	dt	o
operators	nns	o
and	cc	o
punctuation	nn	o
,	,	o
,	,	o
,	,	o
,	,	o
or	cc	o
To	to	o
allow	vbp	o
complex	jj	o
statements	nns	o
to	to	o
occupy	vb	o
a	dt	o
single	jj	o
line	nn	o
,	,	o
a	dt	o
semicolon	nn	o
may	md	o
be	vb	o
omitted	vbn	o
before	in	o
a	dt	o
closing	vbg	o
or	cc	o
.	.	o
To	to	o
reflect	vb	o
idiomatic	jj	o
use	vb	o
,	,	o
code	nn	o
examples	nns	o
in	in	o
this	dt	o
document	nn	o
elide	vb	o
semicolons	nns	o
using	vbg	o
these	dt	o
rules	nns	o
.	.	o
Identifiers	nnps	o
Identifiers	nnps	o
name	nn	o
program	nn	o
entities	nns	o
such	jj	o
as	in	o
variables	nns	o
and	cc	o
types	nns	o
.	.	o
An	dt	o
identifier	nn	o
is	vbz	o
a	dt	o
sequence	nn	o
of	in	o
one	nn	o
or	cc	o
more	jjr	o
letters	nns	o
and	cc	o
digits	nns	o
.	.	o
The	dt	o
first	jj	o
character	nn	o
in	in	o
an	dt	o
identifier	nn	o
must	md	o
be	vb	o
a	dt	o
letter	nn	o
.	.	o
Some	dt	o
identifiers	nns	o
are	vbp	o
predeclared	vbn	o
.	.	o
Keywords	vb	o
The	dt	o
following	vbg	o
keywords	nns	o
are	vbp	o
reserved	vbn	o
and	cc	o
may	md	o
not	rb	o
be	vb	o
used	vbn	o
as	in	o
identifiers	nns	o
.	.	o
break	nn	o
default	nn	o
func	nn	o
interface	nn	o
select	nn	o
case	nn	o
defer	nn	o
go	vbp	o
map	nn	o
struct	nn	o
chan	vbp	o
else	rb	o
goto	jj	o
package	nn	o
switch	vb	o
const	nn	o
fallthrough	in	o
if	in	o
range	nn	o
type	nn	o
continue	nn	o
for	in	o
import	nn	o
return	vb	o
var	nn	o
Operators	nnps	o
and	cc	o
punctuation	nn	o
The	dt	o
following	vbg	o
character	nn	o
sequences	vbz	o
represent	vbp	o
operators	nns	o
(	(	o
including	vbg	o
assignment	nn	o
operators	nns	o
)	)	o
and	cc	o
punctuation	nn	o
:	:	o
+	jj	o
&	cc	o
+=	vbd	o
&=	nnp	o
&&	nnp	o
==	cc	o
!=	nn	o
(	(	o
)	)	o
-	-	o
|	vbp	o
-=	nnp	o
|=	nnp	o
||	nnp	o
<	nnp	o
<=	rb	o
[	nnp	o
]	nnp	o
*	-none-	o
^	nnp	o
*=	nnp	o
^=	nnp	o
<-	jj	o
>	nn	o
>=	jj	o
{	(	o
}	)	o
/	vbp	o
<<	nnp	o
/=	nnp	o
<<=	nnp	o
++	nnp	o
=	nnp	o
:=	nnp	o
,	,	o
;	:	o
%	nn	o
>>	nnp	o
%=	jj	o
>>=	nnp	o
--	:	o
!	.	o
.	.	o
.	.	o
.	.	o
.	.	o
:	:	o
&^	vbp	o
&^=	nnp	o
~	nnp	o
Integer	jjr	o
literals	nns	o
An	dt	o
integer	jj	o
literal	nn	o
is	vbz	o
a	dt	o
sequence	nn	o
of	in	o
digits	nns	o
representing	vbg	o
an	dt	o
integer	jj	o
constant	nn	o
.	.	o
An	dt	o
optional	jj	o
prefix	nn	o
sets	vbz	o
a	dt	o
non-decimal	jj	o
base	nn	o
:	:	o
or	cc	o
for	in	o
binary	jj	o
,	,	o
,	,	o
,	,	o
or	cc	o
for	in	o
octal	jj	o
,	,	o
and	cc	o
or	cc	o
for	in	o
hexadecimal	jj	o
.	.	o
A	dt	o
single	jj	o
is	vbz	o
considered	vbn	o
a	dt	o
decimal	jj	o
zero	cd	o
.	.	o
In	in	o
hexadecimal	nn	o
literals	nns	o
,	,	o
letters	nns	o
through	in	o
and	cc	o
through	in	o
represent	vbp	o
values	nns	o
10	cd	o
through	in	o
15	cd	o
.	.	o
For	in	o
readability	nn	o
,	,	o
an	dt	o
underscore	jj	o
character	nn	o
may	md	o
appear	vbp	o
after	in	o
a	dt	o
base	nn	o
prefix	nn	o
or	cc	o
between	in	o
successive	jj	o
digits	nns	o
;	:	o
such	jj	o
underscores	nns	o
do	vbp	o
not	rb	o
change	vbp	o
the	dt	o
literal	nn	o
's	pos	o
value	nn	o
.	.	o
Floating-point	jj	o
literals	nns	o
A	dt	o
floating-point	nn	o
literal	nn	o
is	vbz	o
a	dt	o
decimal	jj	o
or	cc	o
hexadecimal	nn	o
representation	nn	o
of	in	o
a	dt	o
floating-point	nn	o
constant	nn	o
.	.	o
A	dt	o
decimal	jj	o
floating-point	nn	o
literal	nn	o
consists	vbz	o
of	in	o
an	dt	o
integer	jj	o
part	nn	o
(	(	o
decimal	jj	o
digits	nns	o
)	)	o
,	,	o
a	dt	o
decimal	jj	o
point	nn	o
,	,	o
a	dt	o
fractional	jj	o
part	nn	o
(	(	o
decimal	jj	o
digits	nns	o
)	)	o
,	,	o
and	cc	o
an	dt	o
exponent	nn	o
part	nn	o
(	(	o
or	cc	o
followed	vbn	o
by	in	o
an	dt	o
optional	jj	o
sign	jj	o
and	cc	o
decimal	jj	o
digits	nns	o
)	)	o
.	.	o
One	cd	o
of	in	o
the	dt	o
integer	jj	o
part	nn	o
or	cc	o
the	dt	o
fractional	jj	o
part	nn	o
may	md	o
be	vb	o
elided	vbn	o
;	:	o
one	nn	o
of	in	o
the	dt	o
decimal	jj	o
point	nn	o
or	cc	o
the	dt	o
exponent	nn	o
part	nn	o
may	md	o
be	vb	o
elided	vbn	o
.	.	o
An	dt	o
exponent	nn	o
value	nn	o
exp	nn	o
scales	vbz	o
the	dt	o
mantissa	nn	o
(	(	o
integer	nn	o
and	cc	o
fractional	jj	o
part	nn	o
)	)	o
by	in	o
10exp	cd	o
.	.	o
A	dt	o
hexadecimal	nn	o
floating-point	nn	o
literal	nn	o
consists	vbz	o
of	in	o
a	dt	o
or	cc	o
prefix	nn	o
,	,	o
an	dt	o
integer	jj	o
part	nn	o
(	(	o
hexadecimal	jj	o
digits	nns	o
)	)	o
,	,	o
a	dt	o
radix	nn	o
point	nn	o
,	,	o
a	dt	o
fractional	jj	o
part	nn	o
(	(	o
hexadecimal	jj	o
digits	nns	o
)	)	o
,	,	o
and	cc	o
an	dt	o
exponent	nn	o
part	nn	o
(	(	o
or	cc	o
followed	vbn	o
by	in	o
an	dt	o
optional	jj	o
sign	jj	o
and	cc	o
decimal	jj	o
digits	nns	o
)	)	o
.	.	o
One	cd	o
of	in	o
the	dt	o
integer	jj	o
part	nn	o
or	cc	o
the	dt	o
fractional	jj	o
part	nn	o
may	md	o
be	vb	o
elided	vbn	o
;	:	o
the	dt	o
radix	nn	o
point	nn	o
may	md	o
be	vb	o
elided	vbn	o
as	in	o
well	rb	o
,	,	o
but	cc	o
the	dt	o
exponent	nn	o
part	nn	o
is	vbz	o
required	vbn	o
.	.	o
(	(	o
This	dt	o
syntax	nn	o
matches	nns	o
the	dt	o
one	nn	o
given	vbn	o
in	in	o
IEEE	nnp	o
754-2008	jj	o
§5.12.3	nn	o
.	.	o
)	)	o
An	dt	o
exponent	nn	o
value	nn	o
exp	nn	o
scales	vbz	o
the	dt	o
mantissa	nn	o
(	(	o
integer	nn	o
and	cc	o
fractional	jj	o
part	nn	o
)	)	o
by	in	o
2exp	cd	o
.	.	o
For	in	o
readability	nn	o
,	,	o
an	dt	o
underscore	jj	o
character	nn	o
may	md	o
appear	vbp	o
after	in	o
a	dt	o
base	nn	o
prefix	nn	o
or	cc	o
between	in	o
successive	jj	o
digits	nns	o
;	:	o
such	jj	o
underscores	nns	o
do	vbp	o
not	rb	o
change	vbp	o
the	dt	o
literal	nn	o
value	nn	o
.	.	o
Imaginary	nnp	o
literals	nns	o
An	dt	o
imaginary	jj	o
literal	nn	o
represents	vbz	o
the	dt	o
imaginary	jj	o
part	nn	o
of	in	o
a	dt	o
complex	jj	o
constant	nn	o
.	.	o
It	prp	o
consists	vbz	o
of	in	o
an	dt	o
integer	jj	o
or	cc	o
floating-point	nn	o
literal	nn	o
followed	vbn	o
by	in	o
the	dt	o
lower-case	jj	o
letter	nn	o
.	.	o
The	dt	o
value	nn	o
of	in	o
an	dt	o
imaginary	jj	o
literal	nn	o
is	vbz	o
the	dt	o
value	nn	o
of	in	o
the	dt	o
respective	jj	o
integer	jj	o
or	cc	o
floating-point	nn	o
literal	nn	o
multiplied	vbn	o
by	in	o
the	dt	o
imaginary	jj	o
unit	nn	o
i	nn	o
.	.	o
For	in	o
backward	jj	o
compatibility	nn	o
,	,	o
an	dt	o
imaginary	jj	o
literal	nn	o
's	pos	o
integer	jj	o
part	nn	o
consisting	nn	o
entirely	rb	o
of	in	o
decimal	jj	o
digits	nns	o
(	(	o
and	cc	o
possibly	rb	o
underscores	nns	o
)	)	o
is	vbz	o
considered	vbn	o
a	dt	o
decimal	jj	o
integer	nn	o
,	,	o
even	rb	o
if	in	o
it	prp	o
starts	vbz	o
with	in	o
a	dt	o
leading	vbg	o
.	.	o
Rune	nnp	o
literals	nns	o
A	dt	o
rune	nns	o
literal	nn	o
represents	vbz	o
a	dt	o
rune	nns	o
constant	nn	o
,	,	o
an	dt	o
integer	jj	o
value	nn	o
identifying	vbg	o
a	dt	o
Unicode	nnp	b-gpe
code	nn	o
point	nn	o
.	.	o
A	dt	o
rune	nns	o
literal	nn	o
is	vbz	o
expressed	vbn	o
as	in	o
one	nn	o
or	cc	o
more	jjr	o
characters	nns	o
enclosed	vbn	o
in	in	o
single	jj	o
quotes	nns	o
,	,	o
as	in	o
in	in	o
or	cc	o
.	.	o
Within	in	o
the	dt	o
quotes	nns	o
,	,	o
any	dt	o
character	nn	o
may	md	o
appear	vbp	o
except	vb	o
newline	nn	o
and	cc	o
unescaped	jj	o
single	jj	o
quote	nn	o
.	.	o
A	dt	o
single	jj	o
quoted	vbn	o
character	nn	o
represents	vbz	o
the	dt	o
Unicode	nnp	b-gpe
value	nn	o
of	in	o
the	dt	o
character	nn	o
itself	prp	o
,	,	o
while	in	o
multi-character	jj	o
sequences	vbz	o
beginning	vbg	o
with	in	o
a	dt	o
backslash	jj	o
encode	nn	o
values	nns	o
in	in	o
various	jj	o
formats	nns	o
.	.	o
The	dt	o
simplest	jjs	o
form	nn	o
represents	vbz	o
the	dt	o
single	jj	o
character	nn	o
within	in	o
the	dt	o
quotes	nns	o
;	:	o
since	in	o
Go	nnp	o
source	nn	o
text	nn	o
is	vbz	o
Unicode	nnp	b-gpe
characters	nns	o
encoded	vbn	o
in	in	o
UTF-8	nnp	b-gpe
,	,	o
multiple	nn	o
UTF-8-encoded	jj	o
bytes	nns	o
may	md	o
represent	vbp	o
a	dt	o
single	jj	o
integer	jj	o
value	nn	o
.	.	o
For	in	o
instance	nn	o
,	,	o
the	dt	o
literal	nn	o
holds	vbz	o
a	dt	o
single	jj	o
byte	nn	o
representing	vbg	o
a	dt	o
literal	nn	o
,	,	o
Unicode	nnp	b-gpe
U+0061	nnp	i-person
,	,	o
value	nn	o
,	,	o
while	in	o
holds	vbz	o
two	cd	o
bytes	nns	o
(	(	o
)	)	o
representing	vbg	o
a	dt	o
literal	nn	o
-dieresis	nn	o
,	,	o
U+00E4	nnp	b-gpe
,	,	o
value	nn	o
.	.	o
Several	jj	o
backslash	jj	o
escapes	nns	o
allow	vbp	o
arbitrary	jj	o
values	nns	o
to	to	o
be	vb	o
encoded	vbn	o
as	in	o
ASCII	nnp	b-gpe
text	nn	o
.	.	o
There	ex	o
are	vbp	o
four	cd	o
ways	nns	o
to	to	o
represent	vbp	o
the	dt	o
integer	jj	o
value	nn	o
as	in	o
a	dt	o
numeric	jj	o
constant	nn	o
:	:	o
followed	vbn	o
by	in	o
exactly	rb	o
two	cd	o
hexadecimal	nn	o
digits	nns	o
;	:	o
followed	vbn	o
by	in	o
exactly	rb	o
four	cd	o
hexadecimal	nn	o
digits	nns	o
;	:	o
followed	vbn	o
by	in	o
exactly	rb	o
eight	cd	o
hexadecimal	nn	o
digits	nns	o
,	,	o
and	cc	o
a	dt	o
plain	nn	o
backslash	jj	o
followed	vbn	o
by	in	o
exactly	rb	o
three	cd	o
octal	nn	o
digits	nns	o
.	.	o
In	in	o
each	dt	o
case	nn	o
the	dt	o
value	nn	o
of	in	o
the	dt	o
literal	nn	o
is	vbz	o
the	dt	o
value	nn	o
represented	vbn	o
by	in	o
the	dt	o
digits	nns	o
in	in	o
the	dt	o
corresponding	jj	o
base	nn	o
.	.	o
Although	in	o
these	dt	o
representations	nns	o
all	pdt	o
result	nn	o
in	in	o
an	dt	o
integer	nn	o
,	,	o
they	prp	o
have	vb	o
different	jj	o
valid	jj	o
ranges	nns	o
.	.	o
Octal	jj	o
escapes	nns	o
must	md	o
represent	vbp	o
a	dt	o
value	nn	o
between	in	o
0	-none-	o
and	cc	o
255	cd	o
inclusive	jj	o
.	.	o
Hexadecimal	nnp	o
escapes	nns	o
satisfy	vbp	o
this	dt	o
condition	nn	o
by	in	o
construction	nn	o
.	.	o
The	dt	o
escapes	nns	o
and	cc	o
represent	vbp	o
Unicode	nnp	b-gpe
code	nn	o
points	nns	o
so	rb	o
within	in	o
them	prp	o
some	dt	o
values	nns	o
are	vbp	o
illegal	jj	o
,	,	o
in	in	o
particular	jj	o
those	dt	o
above	in	o
and	cc	o
surrogate	jj	o
halves	nns	o
.	.	o
After	in	o
a	dt	o
backslash	nn	o
,	,	o
certain	jj	o
single-character	jj	o
escapes	nns	o
represent	vbp	o
special	jj	o
values	nns	o
:	:	o
\a	nn	o
U+0007	nnp	b-gpe
alert	nn	o
or	cc	o
bell	nn	o
\b	cd	o
U+0008	nnp	b-gpe
backspace	nn	o
\f	nnp	o
U+000C	nnp	o
form	nn	o
feed	nn	o
\n	nnp	o
U+000A	nnp	o
line	nn	o
feed	nn	o
or	cc	o
newline	nn	o
\r	nnp	o
U+000D	nnp	o
carriage	nn	o
return	vb	o
\t	nnp	o
U+0009	nnp	o
horizontal	jj	o
tab	nn	o
\v	nnp	o
U+000B	nnp	o
vertical	jj	o
tab	nn	o
\\	nnp	o
U+005C	nnp	o
backslash	jj	o
\	nnp	o
'	pos	o
U+0027	nnp	b-person
single	jj	o
quote	nn	o
(	(	o
valid	jj	o
escape	nn	o
only	rb	o
within	in	o
rune	nns	o
literals	nns	o
)	)	o
\	vbp	o
"	jj	o
U+0022	nnp	o
double	jj	o
quote	nn	o
(	(	o
valid	jj	o
escape	nn	o
only	rb	o
within	in	o
string	vbg	o
literals	nns	o
)	)	o
All	dt	o
other	jj	o
sequences	vbz	o
starting	vbg	o
with	in	o
a	dt	o
backslash	jj	o
are	vbp	o
illegal	jj	o
inside	in	o
rune	nns	o
literals	nns	o
.	.	o
String	vbg	o
literals	nns	o
A	dt	o
string	vbg	o
literal	nn	o
represents	vbz	o
a	dt	o
string	vbg	o
constant	nn	o
obtained	vbn	o
from	in	o
concatenating	vbg	o
a	dt	o
sequence	nn	o
of	in	o
characters	nns	o
.	.	o
There	ex	o
are	vbp	o
two	cd	o
forms	nns	o
:	:	o
raw	jj	o
string	vbg	o
literals	nns	o
and	cc	o
interpreted	vbn	o
string	vbg	o
literals	nns	o
.	.	o
Raw	nnp	o
string	vbg	o
literals	nns	o
are	vbp	o
character	nn	o
sequences	vbz	o
between	in	o
back	rb	o
quotes	nns	o
,	,	o
as	in	o
in	in	o
.	.	o
Within	in	o
the	dt	o
quotes	nns	o
,	,	o
any	dt	o
character	nn	o
may	md	o
appear	vbp	o
except	vb	o
back	rb	o
quote	nn	o
.	.	o
The	dt	o
value	nn	o
of	in	o
a	dt	o
raw	jj	o
string	vbg	o
literal	nn	o
is	vbz	o
the	dt	o
string	vbg	o
composed	vbn	o
of	in	o
the	dt	o
uninterpreted	jj	o
(	(	o
implicitly	rb	o
UTF-8-encoded	nnp	o
)	)	o
characters	nns	o
between	in	o
the	dt	o
quotes	nns	o
;	:	o
in	in	o
particular	jj	o
,	,	o
backslashes	nns	o
have	vb	o
no	dt	o
special	jj	o
meaning	nn	o
and	cc	o
the	dt	o
string	vbg	o
may	md	o
contain	vb	o
newlines	nns	o
.	.	o
Carriage	nnp	o
return	vb	o
characters	nns	o
(	(	o
'\r	nnp	o
'	pos	o
)	)	o
inside	in	o
raw	jj	o
string	vbg	o
literals	nns	o
are	vbp	o
discarded	vbn	o
from	in	o
the	dt	o
raw	jj	o
string	vbg	o
value	nn	o
.	.	o
Interpreted	vbn	o
string	vbg	o
literals	nns	o
are	vbp	o
character	nn	o
sequences	vbz	o
between	in	o
double	jj	o
quotes	nns	o
,	,	o
as	in	o
in	in	o
.	.	o
Within	in	o
the	dt	o
quotes	nns	o
,	,	o
any	dt	o
character	nn	o
may	md	o
appear	vbp	o
except	vb	o
newline	nn	o
and	cc	o
unescaped	jj	o
double	jj	o
quote	nn	o
.	.	o
The	dt	o
text	nn	o
between	in	o
the	dt	o
quotes	nns	o
forms	vbp	o
the	dt	o
value	nn	o
of	in	o
the	dt	o
literal	jj	o
,	,	o
with	in	o
backslash	jj	o
escapes	nns	o
interpreted	vbn	o
as	in	o
they	prp	o
are	vbp	o
in	in	o
rune	nns	o
literals	nns	o
(	(	o
except	in	o
that	wdt	o
is	vbz	o
illegal	jj	o
and	cc	o
is	vbz	o
legal	jj	o
)	)	o
,	,	o
with	in	o
the	dt	o
same	jj	o
restrictions	nns	o
.	.	o
The	dt	o
three-digit	jj	o
octal	nn	o
(	(	o
nnn	jj	o
)	)	o
and	cc	o
two-digit	jj	o
hexadecimal	nn	o
(	(	o
nn	jj	o
)	)	o
escapes	nns	o
represent	vbp	o
individual	jj	o
bytes	nns	o
of	in	o
the	dt	o
resulting	vbg	o
string	nn	o
;	:	o
all	pdt	o
other	jj	o
escapes	nns	o
represent	vbp	o
the	dt	o
(	(	o
possibly	rb	o
multi-byte	nn	o
)	)	o
UTF-8	jj	o
encoding	nn	o
of	in	o
individual	jj	o
characters	nns	o
.	.	o
Thus	nnp	o
inside	in	o
a	dt	o
string	vbg	o
literal	nn	o
and	cc	o
represent	vbp	o
a	dt	o
single	jj	o
byte	nn	o
of	in	o
value	nn	o
=255	nnp	o
,	,	o
while	in	o
,	,	o
,	,	o
and	cc	o
represent	vbp	o
the	dt	o
two	cd	o
bytes	nns	o
of	in	o
the	dt	o
UTF-8	jj	o
encoding	nn	o
of	in	o
character	nn	o
U+00FF	nnp	b-gpe
.	.	o
These	dt	o
examples	nns	o
all	pdt	o
represent	vbp	o
the	dt	o
same	jj	o
string	nn	o
:	:	o
If	in	o
the	dt	o
source	nn	o
code	nn	o
represents	vbz	o
a	dt	o
character	nn	o
as	in	o
two	cd	o
code	nn	o
points	nns	o
,	,	o
such	jj	o
as	in	o
a	dt	o
combining	vbg	o
form	nn	o
involving	vbg	o
an	dt	o
accent	nn	o
and	cc	o
a	dt	o
letter	nn	o
,	,	o
the	dt	o
result	nn	o
will	md	o
be	vb	o
an	dt	o
error	nn	o
if	in	o
placed	vbn	o
in	in	o
a	dt	o
rune	nns	o
literal	nn	o
(	(	o
it	prp	o
is	vbz	o
not	rb	o
a	dt	o
single	jj	o
code	nn	o
point	nn	o
)	)	o
,	,	o
and	cc	o
will	md	o
appear	vbp	o
as	in	o
two	cd	o
code	nn	o
points	nns	o
if	in	o
placed	vbn	o
in	in	o
a	dt	o
string	vbg	o
literal	jj	o
.	.	o
Constants	nns	o
There	ex	o
are	vbp	o
boolean	jj	o
constants	nns	o
,	,	o
rune	nns	o
constants	nns	o
,	,	o
integer	jj	o
constants	nns	o
,	,	o
floating-point	nn	o
constants	nns	o
,	,	o
complex	jj	o
constants	nns	o
,	,	o
and	cc	o
string	vbg	o
constants	nns	o
.	.	o
Rune	nnp	o
,	,	o
integer	nn	o
,	,	o
floating-point	jj	o
,	,	o
and	cc	o
complex	jj	o
constants	nns	o
are	vbp	o
collectively	rb	o
called	vbd	o
numeric	jj	o
constants	nns	o
.	.	o
A	dt	o
constant	nn	o
value	nn	o
is	vbz	o
represented	vbn	o
by	in	o
a	dt	o
rune	nn	o
,	,	o
integer	nn	o
,	,	o
floating-point	jj	o
,	,	o
imaginary	jj	o
,	,	o
or	cc	o
string	vbg	o
literal	jj	o
,	,	o
an	dt	o
identifier	nn	o
denoting	vbg	o
a	dt	o
constant	nn	o
,	,	o
a	dt	o
constant	nn	o
expression	nn	o
,	,	o
a	dt	o
conversion	nn	o
with	in	o
a	dt	o
result	nn	o
that	wdt	o
is	vbz	o
a	dt	o
constant	nn	o
,	,	o
or	cc	o
the	dt	o
result	nn	o
value	nn	o
of	in	o
some	dt	o
built-in	jj	o
functions	nns	o
such	jj	o
as	in	o
applied	vbd	o
to	to	o
certain	jj	o
values	nns	o
,	,	o
or	cc	o
applied	vbd	o
to	to	o
some	dt	o
expressions	nns	o
,	,	o
and	cc	o
applied	vbd	o
to	to	o
a	dt	o
complex	jj	o
constant	nn	o
and	cc	o
applied	vbd	o
to	to	o
numeric	jj	o
constants	nns	o
.	.	o
The	dt	o
boolean	jj	o
truth	nn	o
values	nns	o
are	vbp	o
represented	vbn	o
by	in	o
the	dt	o
predeclared	jj	o
constants	nns	o
and	cc	o
.	.	o
The	dt	o
predeclared	jj	o
identifier	nn	o
iota	nn	o
denotes	vbz	o
an	dt	o
integer	jj	o
constant	nn	o
.	.	o
In	in	o
general	jj	o
,	,	o
complex	jj	o
constants	nns	o
are	vbp	o
a	dt	o
form	nn	o
of	in	o
constant	nn	o
expression	nn	o
and	cc	o
are	vbp	o
discussed	vbn	o
in	in	o
that	wdt	o
section	nn	o
.	.	o
Numeric	nnp	o
constants	nns	o
represent	vbp	o
exact	jj	o
values	nns	o
of	in	o
arbitrary	jj	o
precision	nn	o
and	cc	o
do	vbp	o
not	rb	o
overflow	nn	o
.	.	o
Consequently	rb	o
,	,	o
there	ex	o
are	vbp	o
no	dt	o
constants	nns	o
denoting	vbg	o
the	dt	o
IEEE-754	jj	o
negative	jj	o
zero	cd	o
,	,	o
infinity	nn	o
,	,	o
and	cc	o
not-a-number	jj	o
values	nns	o
.	.	o
Constants	nns	o
may	md	o
be	vb	o
typed	jj	o
or	cc	o
untyped	jj	o
.	.	o
Literal	jj	o
constants	nns	o
,	,	o
,	,	o
,	,	o
,	,	o
and	cc	o
certain	jj	o
constant	nn	o
expressions	nns	o
containing	vbg	o
only	rb	o
untyped	jj	o
constant	nn	o
operands	nns	o
are	vbp	o
untyped	jj	o
.	.	o
A	dt	o
constant	nn	o
may	md	o
be	vb	o
given	vbn	o
a	dt	o
type	nn	o
explicitly	rb	o
by	in	o
a	dt	o
constant	nn	o
declaration	nn	o
or	cc	o
conversion	nn	o
,	,	o
or	cc	o
implicitly	rb	o
when	wrb	o
used	vbn	o
in	in	o
a	dt	o
variable	nn	o
declaration	nn	o
or	cc	o
an	dt	o
assignment	nn	o
or	cc	o
as	in	o
an	dt	o
operand	nn	o
in	in	o
an	dt	o
expression	nn	o
.	.	o
It	prp	o
is	vbz	o
an	dt	o
error	nn	o
if	in	o
the	dt	o
constant	nn	o
value	nn	o
cannot	vbp	o
be	vb	o
represented	vbn	o
as	in	o
a	dt	o
value	nn	o
of	in	o
the	dt	o
respective	jj	o
type	nn	o
.	.	o
If	in	o
the	dt	o
type	nn	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
the	dt	o
constant	nn	o
is	vbz	o
converted	vbn	o
into	in	o
a	dt	o
non-constant	jj	o
value	nn	o
of	in	o
the	dt	o
type	nn	o
parameter	nn	o
.	.	o
An	dt	o
untyped	jj	o
constant	nn	o
has	vbz	o
a	dt	o
default	nn	o
type	nn	o
which	wdt	o
is	vbz	o
the	dt	o
type	nn	o
to	to	o
which	wdt	o
the	dt	o
constant	nn	o
is	vbz	o
implicitly	rb	o
converted	vbn	o
in	in	o
contexts	nns	o
where	wrb	o
a	dt	o
typed	jj	o
value	nn	o
is	vbz	o
required	vbn	o
,	,	o
for	in	o
instance	nn	o
,	,	o
in	in	o
a	dt	o
short	jj	o
variable	nn	o
declaration	nn	o
such	jj	o
as	in	o
where	wrb	o
there	ex	o
is	vbz	o
no	dt	o
explicit	jj	o
type	nn	o
.	.	o
The	dt	o
default	nn	o
type	nn	o
of	in	o
an	dt	o
untyped	jj	o
constant	nn	o
is	vbz	o
,	,	o
,	,	o
,	,	o
,	,	o
or	cc	o
respectively	rb	o
,	,	o
depending	vbg	o
on	in	o
whether	in	o
it	prp	o
is	vbz	o
a	dt	o
boolean	nn	o
,	,	o
rune	nn	o
,	,	o
integer	nn	o
,	,	o
floating-point	jj	o
,	,	o
complex	jj	o
,	,	o
or	cc	o
string	vbg	o
constant	nn	o
.	.	o
Implementation	nnp	o
restriction	nn	o
:	:	o
Although	in	o
numeric	jj	o
constants	nns	o
have	vb	o
arbitrary	jj	o
precision	nn	o
in	in	o
the	dt	o
language	nn	o
,	,	o
a	dt	o
compiler	nn	o
may	md	o
implement	vb	o
them	prp	o
using	vbg	o
an	dt	o
internal	jj	o
representation	nn	o
with	in	o
limited	jj	o
precision	nn	o
.	.	o
That	dt	o
said	vbd	o
,	,	o
every	dt	o
implementation	nn	o
must	md	o
:	:	o
Represent	jj	o
integer	jj	o
constants	nns	o
with	in	o
at	in	o
least	jjs	o
256	cd	o
bits	nns	o
.	.	o
Represent	jj	o
floating-point	nn	o
constants	nns	o
,	,	o
including	vbg	o
the	dt	o
parts	nns	o
of	in	o
a	dt	o
complex	jj	o
constant	nn	o
,	,	o
with	in	o
a	dt	o
mantissa	nn	o
of	in	o
at	in	o
least	jjs	o
256	cd	o
bits	nns	o
and	cc	o
a	dt	o
signed	vbn	o
binary	jj	o
exponent	nn	o
of	in	o
at	in	o
least	jjs	o
16	cd	o
bits	nns	o
.	.	o
Give	vb	o
an	dt	o
error	nn	o
if	in	o
unable	jj	o
to	to	o
represent	vbp	o
an	dt	o
integer	jj	o
constant	nn	o
precisely	rb	o
.	.	o
Give	vb	o
an	dt	o
error	nn	o
if	in	o
unable	jj	o
to	to	o
represent	vbp	o
a	dt	o
floating-point	nn	o
or	cc	o
complex	jj	o
constant	nn	o
due	jj	o
to	to	o
overflow	nn	o
.	.	o
Round	nnp	o
to	to	o
the	dt	o
nearest	jjs	o
representable	jj	o
constant	nn	o
if	in	o
unable	jj	o
to	to	o
represent	vbp	o
a	dt	o
floating-point	nn	o
or	cc	o
complex	jj	o
constant	nn	o
due	jj	o
to	to	o
limits	nns	o
on	in	o
precision	nn	o
.	.	o
These	dt	o
requirements	nns	o
apply	vbp	o
both	dt	o
to	to	o
literal	nn	o
constants	nns	o
and	cc	o
to	to	o
the	dt	o
result	nn	o
of	in	o
evaluating	vbg	o
constant	nn	o
expressions	nns	o
.	.	o
Variables	nns	o
A	dt	o
variable	nn	o
is	vbz	o
a	dt	o
storage	nn	o
location	nn	o
for	in	o
holding	vbg	o
a	dt	o
value	nn	o
.	.	o
The	dt	o
set	nn	o
of	in	o
permissible	jj	o
values	nns	o
is	vbz	o
determined	vbn	o
by	in	o
the	dt	o
variable	nn	o
's	pos	o
type	nn	o
.	.	o
A	dt	o
variable	nn	o
declaration	nn	o
or	cc	o
,	,	o
for	in	o
function	nn	o
parameters	nns	o
and	cc	o
results	nns	o
,	,	o
the	dt	o
signature	nn	o
of	in	o
a	dt	o
function	nn	o
declaration	nn	o
or	cc	o
function	nn	o
literal	nn	o
reserves	nns	o
storage	nn	o
for	in	o
a	dt	o
named	vbn	o
variable	nn	o
.	.	o
Calling	vbg	o
the	dt	o
built-in	jj	o
function	nn	o
or	cc	o
taking	vbg	o
the	dt	o
address	nn	o
of	in	o
a	dt	o
composite	jj	o
literal	nn	o
allocates	vbz	o
storage	nn	o
for	in	o
a	dt	o
variable	nn	o
at	in	o
run	jj	o
time	nn	o
.	.	o
Such	jj	o
an	dt	o
anonymous	jj	o
variable	nn	o
is	vbz	o
referred	vbn	o
to	to	o
via	in	o
a	dt	o
(	(	o
possibly	rb	o
implicit	nn	o
)	)	o
pointer	nn	o
indirection	nn	o
.	.	o
Structured	nnp	o
variables	nns	o
of	in	o
array	vb	o
,	,	o
slice	nn	o
,	,	o
and	cc	o
struct	nn	o
types	nns	o
have	vb	o
elements	nns	o
and	cc	o
fields	nns	o
that	wdt	o
may	md	o
be	vb	o
addressed	vbn	o
individually	rb	o
.	.	o
Each	dt	o
such	jj	o
element	nn	o
acts	vbz	o
like	in	o
a	dt	o
variable	nn	o
.	.	o
The	dt	o
static	jj	o
type	nn	o
(	(	o
or	cc	o
just	rb	o
type	nn	o
)	)	o
of	in	o
a	dt	o
variable	nn	o
is	vbz	o
the	dt	o
type	nn	o
given	vbn	o
in	in	o
its	prp$	o
declaration	nn	o
,	,	o
the	dt	o
type	nn	o
provided	vbn	o
in	in	o
the	dt	o
call	nn	o
or	cc	o
composite	jj	o
literal	jj	o
,	,	o
or	cc	o
the	dt	o
type	nn	o
of	in	o
an	dt	o
element	nn	o
of	in	o
a	dt	o
structured	jj	o
variable	nn	o
.	.	o
Variables	nns	o
of	in	o
interface	nn	o
type	nn	o
also	rb	o
have	vb	o
a	dt	o
distinct	jj	o
dynamic	jj	o
type	nn	o
,	,	o
which	wdt	o
is	vbz	o
the	dt	o
concrete	jj	o
type	nn	o
of	in	o
the	dt	o
value	nn	o
assigned	vbn	o
to	to	o
the	dt	o
variable	nn	o
at	in	o
run	jj	o
time	nn	o
(	(	o
unless	in	o
the	dt	o
value	nn	o
is	vbz	o
the	dt	o
predeclared	jj	o
identifier	nn	o
,	,	o
which	wdt	o
has	vbz	o
no	dt	o
type	nn	o
)	)	o
.	.	o
The	dt	o
dynamic	jj	o
type	nn	o
may	md	o
vary	vb	o
during	in	o
execution	nn	o
but	cc	o
values	nns	o
stored	vbn	o
in	in	o
interface	nn	o
variables	nns	o
are	vbp	o
always	rb	o
assignable	jj	o
to	to	o
the	dt	o
static	jj	o
type	nn	o
of	in	o
the	dt	o
variable	nn	o
.	.	o
A	dt	o
variable	nn	o
's	pos	o
value	nn	o
is	vbz	o
retrieved	vbn	o
by	in	o
referring	vbg	o
to	to	o
the	dt	o
variable	nn	o
in	in	o
an	dt	o
expression	nn	o
;	:	o
it	prp	o
is	vbz	o
the	dt	o
most	jjs	o
recent	jj	o
value	nn	o
assigned	vbn	o
to	to	o
the	dt	o
variable	nn	o
.	.	o
If	in	o
a	dt	o
variable	nn	o
has	vbz	o
not	rb	o
yet	rb	o
been	vbn	o
assigned	vbn	o
a	dt	o
value	nn	o
,	,	o
its	prp$	o
value	nn	o
is	vbz	o
the	dt	o
zero	nn	o
value	nn	o
for	in	o
its	prp$	o
type	nn	o
.	.	o
Types	vbz	o
A	dt	o
type	nn	o
determines	vbz	o
a	dt	o
set	nn	o
of	in	o
values	nns	o
together	rb	o
with	in	o
operations	nns	o
and	cc	o
methods	nns	o
specific	jj	o
to	to	o
those	dt	o
values	nns	o
.	.	o
A	dt	o
type	nn	o
may	md	o
be	vb	o
denoted	vbn	o
by	in	o
a	dt	o
type	nn	o
name	nn	o
,	,	o
if	in	o
it	prp	o
has	vbz	o
one	cd	o
,	,	o
which	wdt	o
must	md	o
be	vb	o
followed	vbn	o
by	in	o
type	nn	o
arguments	nns	o
if	in	o
the	dt	o
type	nn	o
is	vbz	o
generic	jj	o
.	.	o
A	dt	o
type	nn	o
may	md	o
also	rb	o
be	vb	o
specified	vbn	o
using	vbg	o
a	dt	o
type	nn	o
literal	jj	o
,	,	o
which	wdt	o
composes	vbz	o
a	dt	o
type	nn	o
from	in	o
existing	vbg	o
types	nns	o
.	.	o
The	dt	o
language	nn	o
predeclares	vbz	o
certain	jj	o
type	nn	o
names	nns	o
.	.	o
Others	nns	o
are	vbp	o
introduced	vbn	o
with	in	o
type	nn	o
declarations	nns	o
or	cc	o
type	nn	o
parameter	nn	o
lists	nns	o
.	.	o
Composite	jj	o
types—array	nn	o
,	,	o
struct	nn	o
,	,	o
pointer	nn	o
,	,	o
function	nn	o
,	,	o
interface	nn	o
,	,	o
slice	nn	o
,	,	o
map	nn	o
,	,	o
and	cc	o
channel	nns	o
types—may	rb	o
be	vb	o
constructed	vbn	o
using	vbg	o
type	nn	o
literals	nns	o
.	.	o
Predeclared	vbd	o
types	nns	o
,	,	o
defined	vbn	o
types	nns	o
,	,	o
and	cc	o
type	nn	o
parameters	nns	o
are	vbp	o
called	vbd	o
named	vbn	o
types	nns	o
.	.	o
An	dt	o
alias	nn	o
denotes	vbz	o
a	dt	o
named	vbn	o
type	nn	o
if	in	o
the	dt	o
type	nn	o
given	vbn	o
in	in	o
the	dt	o
alias	nn	o
declaration	nn	o
is	vbz	o
a	dt	o
named	vbn	o
type	nn	o
.	.	o
Boolean	jj	b-gpe
types	nns	o
A	dt	o
boolean	jj	o
type	nn	o
represents	vbz	o
the	dt	o
set	nn	o
of	in	o
Boolean	jj	b-gpe
truth	nn	o
values	nns	o
denoted	vbn	o
by	in	o
the	dt	o
predeclared	jj	o
constants	nns	o
and	cc	o
.	.	o
The	dt	o
predeclared	jj	o
boolean	jj	o
type	nn	o
is	vbz	o
;	:	o
it	prp	o
is	vbz	o
a	dt	o
defined	vbn	o
type	nn	o
.	.	o
Numeric	nnp	o
types	nns	o
An	dt	o
integer	nn	o
,	,	o
floating-point	jj	o
,	,	o
or	cc	o
complex	jj	o
type	nn	o
represents	vbz	o
the	dt	o
set	nn	o
of	in	o
integer	nn	o
,	,	o
floating-point	jj	o
,	,	o
or	cc	o
complex	jj	o
values	nns	o
,	,	o
respectively	rb	o
.	.	o
They	prp	o
are	vbp	o
collectively	rb	o
called	vbd	o
numeric	jj	o
types	nns	o
.	.	o
The	dt	o
predeclared	jj	o
architecture-independent	jj	o
numeric	jj	o
types	nns	o
are	vbp	o
:	:	o
uint8	jj	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
unsigned	jj	o
8-bit	nn	o
integers	nns	o
(	(	o
0	-none-	o
to	to	o
255	cd	o
)	)	o
uint16	jj	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
unsigned	jj	o
16-bit	cd	o
integers	nns	o
(	(	o
0	-none-	o
to	to	o
65535	cd	o
)	)	o
uint32	jj	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
unsigned	jj	o
32-bit	jj	o
integers	nns	o
(	(	o
0	-none-	o
to	to	o
4294967295	cd	o
)	)	o
uint64	jj	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
unsigned	jj	o
64-bit	jj	o
integers	nns	o
(	(	o
0	-none-	o
to	to	o
18446744073709551615	cd	o
)	)	o
int8	jj	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
signed	vbn	o
8-bit	nn	o
integers	nns	o
(	(	o
-128	cd	o
to	to	o
127	cd	o
)	)	o
int16	jj	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
signed	vbn	o
16-bit	cd	o
integers	nns	o
(	(	o
-32768	vb	o
to	to	o
32767	cd	o
)	)	o
int32	nn	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
signed	vbn	o
32-bit	jj	o
integers	nns	o
(	(	o
-2147483648	vb	o
to	to	o
2147483647	cd	o
)	)	o
int64	nn	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
signed	vbn	o
64-bit	jj	o
integers	nns	o
(	(	o
-9223372036854775808	vb	o
to	to	o
9223372036854775807	cd	o
)	)	o
float32	vbp	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
IEEE-754	jj	o
32-bit	jj	o
floating-point	nn	o
numbers	nns	o
float64	nn	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
IEEE-754	jj	o
64-bit	jj	o
floating-point	nn	o
numbers	nns	o
complex64	jj	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
complex	jj	o
numbers	nns	o
with	in	o
float32	vbp	o
real	jj	o
and	cc	o
imaginary	jj	o
parts	nns	o
complex128	nn	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
complex	jj	o
numbers	nns	o
with	in	o
float64	nn	o
real	jj	o
and	cc	o
imaginary	jj	o
parts	nns	o
byte	nn	o
alias	nn	o
for	in	o
uint8	jj	o
rune	nns	o
alias	nn	o
for	in	o
int32	nn	o
The	dt	o
value	nn	o
of	in	o
an	dt	o
n-bit	jj	o
integer	jj	o
is	vbz	o
n	in	o
bits	nns	o
wide	jj	o
and	cc	o
represented	vbn	o
using	vbg	o
two	cd	o
's	pos	o
complement	nn	o
arithmetic	jj	o
.	.	o
There	ex	o
is	vbz	o
also	rb	o
a	dt	o
set	nn	o
of	in	o
predeclared	jj	o
integer	jj	o
types	nns	o
with	in	o
implementation-specific	jj	o
sizes	nns	o
:	:	o
uint	jj	o
either	dt	o
32	cd	o
or	cc	o
64	cd	o
bits	nns	o
int	nn	o
same	jj	o
size	nn	o
as	in	o
uint	jj	o
uintptr	vbp	o
an	dt	o
unsigned	jj	o
integer	jj	o
large	jj	o
enough	rb	o
to	to	o
store	vb	o
the	dt	o
uninterpreted	jj	o
bits	nns	o
of	in	o
a	dt	o
pointer	nn	o
value	nn	o
To	to	o
avoid	vb	o
portability	nn	o
issues	nns	o
all	pdt	o
numeric	jj	o
types	nns	o
are	vbp	o
defined	vbn	o
types	nns	o
and	cc	o
thus	rb	o
distinct	jj	o
except	vb	o
,	,	o
which	wdt	o
is	vbz	o
an	dt	o
alias	nn	o
for	in	o
,	,	o
and	cc	o
,	,	o
which	wdt	o
is	vbz	o
an	dt	o
alias	nn	o
for	in	o
.	.	o
Explicit	nnp	b-person
conversions	nns	o
are	vbp	o
required	vbn	o
when	wrb	o
different	jj	o
numeric	jj	o
types	nns	o
are	vbp	o
mixed	vbn	o
in	in	o
an	dt	o
expression	nn	o
or	cc	o
assignment	nn	o
.	.	o
For	in	o
instance	nn	o
,	,	o
and	cc	o
are	vbp	o
not	rb	o
the	dt	o
same	jj	o
type	nn	o
even	rb	o
though	in	o
they	prp	o
may	md	o
have	vb	o
the	dt	o
same	jj	o
size	nn	o
on	in	o
a	dt	o
particular	jj	o
architecture	nn	o
.	.	o
String	vbg	o
types	nns	o
A	dt	o
string	vbg	o
type	nn	o
represents	vbz	o
the	dt	o
set	nn	o
of	in	o
string	vbg	o
values	nns	o
.	.	o
A	dt	o
string	vbg	o
value	nn	o
is	vbz	o
a	dt	o
(	(	o
possibly	rb	o
empty	rb	o
)	)	o
sequence	nn	o
of	in	o
bytes	nns	o
.	.	o
The	dt	o
number	nn	o
of	in	o
bytes	nns	o
is	vbz	o
called	vbd	o
the	dt	o
length	nn	o
of	in	o
the	dt	o
string	vbg	o
and	cc	o
is	vbz	o
never	rb	o
negative	jj	o
.	.	o
Strings	nns	o
are	vbp	o
immutable	jj	o
:	:	o
once	rb	o
created	vbn	o
,	,	o
it	prp	o
is	vbz	o
impossible	jj	o
to	to	o
change	vbp	o
the	dt	o
contents	nns	o
of	in	o
a	dt	o
string	nn	o
.	.	o
The	dt	o
predeclared	jj	o
string	vbg	o
type	nn	o
is	vbz	o
;	:	o
it	prp	o
is	vbz	o
a	dt	o
defined	vbn	o
type	nn	o
.	.	o
The	dt	o
length	nn	o
of	in	o
a	dt	o
string	vbg	o
can	md	o
be	vb	o
discovered	vbn	o
using	vbg	o
the	dt	o
built-in	jj	o
function	nn	o
.	.	o
The	dt	o
length	nn	o
is	vbz	o
a	dt	o
compile-time	jj	o
constant	nn	o
if	in	o
the	dt	o
string	vbg	o
is	vbz	o
a	dt	o
constant	nn	o
.	.	o
A	dt	o
string	nn	o
's	pos	o
bytes	nns	o
can	md	o
be	vb	o
accessed	vbn	o
by	in	o
integer	jj	o
indices	nns	o
0	-none-	o
through	in	o
.	.	o
It	prp	o
is	vbz	o
illegal	jj	o
to	to	o
take	vb	o
the	dt	o
address	nn	o
of	in	o
such	jj	o
an	dt	o
element	nn	o
;	:	o
if	in	o
is	vbz	o
the	dt	o
'th	jj	o
byte	nn	o
of	in	o
a	dt	o
string	nn	o
,	,	o
is	vbz	o
invalid	jj	o
.	.	o
Array	nn	o
types	nns	o
An	dt	o
array	nn	o
is	vbz	o
a	dt	o
numbered	jj	o
sequence	nn	o
of	in	o
elements	nns	o
of	in	o
a	dt	o
single	jj	o
type	nn	o
,	,	o
called	vbd	o
the	dt	o
element	nn	o
type	nn	o
.	.	o
The	dt	o
number	nn	o
of	in	o
elements	nns	o
is	vbz	o
called	vbd	o
the	dt	o
length	nn	o
of	in	o
the	dt	o
array	nn	o
and	cc	o
is	vbz	o
never	rb	o
negative	jj	o
.	.	o
The	dt	o
length	nn	o
is	vbz	o
part	nn	o
of	in	o
the	dt	o
array	nn	o
's	pos	o
type	nn	o
;	:	o
it	prp	o
must	md	o
evaluate	vbp	o
to	to	o
a	dt	o
non-negative	jj	o
constant	nn	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
.	.	o
The	dt	o
length	nn	o
of	in	o
array	nn	o
can	md	o
be	vb	o
discovered	vbn	o
using	vbg	o
the	dt	o
built-in	jj	o
function	nn	o
.	.	o
The	dt	o
elements	nns	o
can	md	o
be	vb	o
addressed	vbn	o
by	in	o
integer	jj	o
indices	nns	o
0	-none-	o
through	in	o
.	.	o
Array	nn	o
types	nns	o
are	vbp	o
always	rb	o
one-dimensional	jj	o
but	cc	o
may	md	o
be	vb	o
composed	vbn	o
to	to	o
form	nn	o
multi-dimensional	jj	o
types	nns	o
.	.	o
Slice	nnp	o
types	nns	o
A	dt	o
slice	nn	o
is	vbz	o
a	dt	o
descriptor	nn	o
for	in	o
a	dt	o
contiguous	jj	o
segment	nn	o
of	in	o
an	dt	o
underlying	jj	o
array	nn	o
and	cc	o
provides	vbz	o
access	nn	o
to	to	o
a	dt	o
numbered	jj	o
sequence	nn	o
of	in	o
elements	nns	o
from	in	o
that	wdt	o
array	nn	o
.	.	o
A	dt	o
slice	nn	o
type	nn	o
denotes	vbz	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
slices	nns	o
of	in	o
arrays	nns	o
of	in	o
its	prp$	o
element	nn	o
type	nn	o
.	.	o
The	dt	o
number	nn	o
of	in	o
elements	nns	o
is	vbz	o
called	vbd	o
the	dt	o
length	nn	o
of	in	o
the	dt	o
slice	nn	o
and	cc	o
is	vbz	o
never	rb	o
negative	jj	o
.	.	o
The	dt	o
value	nn	o
of	in	o
an	dt	o
uninitialized	jj	o
slice	nn	o
is	vbz	o
.	.	o
The	dt	o
length	nn	o
of	in	o
a	dt	o
slice	nn	o
can	md	o
be	vb	o
discovered	vbn	o
by	in	o
the	dt	o
built-in	jj	o
function	nn	o
;	:	o
unlike	in	o
with	in	o
arrays	nns	o
it	prp	o
may	md	o
change	vbp	o
during	in	o
execution	nn	o
.	.	o
The	dt	o
elements	nns	o
can	md	o
be	vb	o
addressed	vbn	o
by	in	o
integer	jj	o
indices	nns	o
0	-none-	o
through	in	o
.	.	o
The	dt	o
slice	nn	o
index	nn	o
of	in	o
a	dt	o
given	vbn	o
element	nn	o
may	md	o
be	vb	o
less	jjr	o
than	in	o
the	dt	o
index	nn	o
of	in	o
the	dt	o
same	jj	o
element	nn	o
in	in	o
the	dt	o
underlying	jj	o
array	nn	o
.	.	o
A	dt	o
slice	nn	o
,	,	o
once	rb	o
initialized	vbn	o
,	,	o
is	vbz	o
always	rb	o
associated	jj	o
with	in	o
an	dt	o
underlying	jj	o
array	nn	o
that	wdt	o
holds	vbz	o
its	prp$	o
elements	nns	o
.	.	o
A	dt	o
slice	nn	o
therefore	rb	o
shares	nns	o
storage	nn	o
with	in	o
its	prp$	o
array	nn	o
and	cc	o
with	in	o
other	jj	o
slices	nns	o
of	in	o
the	dt	o
same	jj	o
array	nn	o
;	:	o
by	in	o
contrast	nn	o
,	,	o
distinct	jj	o
arrays	nns	o
always	rb	o
represent	vbp	o
distinct	jj	o
storage	nn	o
.	.	o
The	dt	o
array	nn	o
underlying	jj	o
a	dt	o
slice	nn	o
may	md	o
extend	vb	o
past	in	o
the	dt	o
end	nn	o
of	in	o
the	dt	o
slice	nn	o
.	.	o
The	dt	o
capacity	nn	o
is	vbz	o
a	dt	o
measure	nn	o
of	in	o
that	wdt	o
extent	nn	o
:	:	o
it	prp	o
is	vbz	o
the	dt	o
sum	jj	o
of	in	o
the	dt	o
length	nn	o
of	in	o
the	dt	o
slice	nn	o
and	cc	o
the	dt	o
length	nn	o
of	in	o
the	dt	o
array	nn	o
beyond	in	o
the	dt	o
slice	nn	o
;	:	o
a	dt	o
slice	nn	o
of	in	o
length	nn	o
up	in	o
to	to	o
that	wdt	o
capacity	nn	o
can	md	o
be	vb	o
created	vbn	o
by	in	o
slicing	vbg	o
a	dt	o
new	jj	o
one	nn	o
from	in	o
the	dt	o
original	jj	o
slice	nn	o
.	.	o
The	dt	o
capacity	nn	o
of	in	o
a	dt	o
slice	nn	o
can	md	o
be	vb	o
discovered	vbn	o
using	vbg	o
the	dt	o
built-in	jj	o
function	nn	o
.	.	o
A	dt	o
new	jj	o
,	,	o
initialized	vbn	o
slice	nn	o
value	nn	o
for	in	o
a	dt	o
given	vbn	o
element	nn	o
type	nn	o
is	vbz	o
made	vbn	o
using	vbg	o
the	dt	o
built-in	jj	o
function	nn	o
,	,	o
which	wdt	o
takes	vbz	o
a	dt	o
slice	nn	o
type	nn	o
and	cc	o
parameters	nns	o
specifying	vbg	o
the	dt	o
length	nn	o
and	cc	o
optionally	rb	o
the	dt	o
capacity	nn	o
.	.	o
A	dt	o
slice	nn	o
created	vbn	o
with	in	o
always	rb	o
allocates	vbz	o
a	dt	o
new	jj	o
,	,	o
hidden	jj	o
array	nn	o
to	to	o
which	wdt	o
the	dt	o
returned	vbn	o
slice	nn	o
value	nn	o
refers	nns	o
.	.	o
That	dt	o
is	vbz	o
,	,	o
executing	vbg	o
produces	vbz	o
the	dt	o
same	jj	o
slice	nn	o
as	in	o
allocating	vbg	o
an	dt	o
array	nn	o
and	cc	o
slicing	vbg	o
it	prp	o
,	,	o
so	rb	o
these	dt	o
two	cd	o
expressions	nns	o
are	vbp	o
equivalent	jj	o
:	:	o
Like	in	o
arrays	nns	o
,	,	o
slices	nns	o
are	vbp	o
always	rb	o
one-dimensional	jj	o
but	cc	o
may	md	o
be	vb	o
composed	vbn	o
to	to	o
construct	nn	o
higher-dimensional	jj	o
objects	nns	o
.	.	o
With	in	o
arrays	nns	o
of	in	o
arrays	nns	o
,	,	o
the	dt	o
inner	jj	o
arrays	nns	o
are	vbp	o
,	,	o
by	in	o
construction	nn	o
,	,	o
always	rb	o
the	dt	o
same	jj	o
length	nn	o
;	:	o
however	rb	o
with	in	o
slices	nns	o
of	in	o
slices	nns	o
(	(	o
or	cc	o
arrays	nns	o
of	in	o
slices	nns	o
)	)	o
,	,	o
the	dt	o
inner	jj	o
lengths	nns	o
may	md	o
vary	vb	o
dynamically	rb	o
.	.	o
Moreover	rb	o
,	,	o
the	dt	o
inner	jj	o
slices	nns	o
must	md	o
be	vb	o
initialized	vbn	o
individually	rb	o
.	.	o
Struct	nnp	o
types	nns	o
A	dt	o
struct	nn	o
is	vbz	o
a	dt	o
sequence	nn	o
of	in	o
named	vbn	o
elements	nns	o
,	,	o
called	vbd	o
fields	nns	o
,	,	o
each	dt	o
of	in	o
which	wdt	o
has	vbz	o
a	dt	o
name	nn	o
and	cc	o
a	dt	o
type	nn	o
.	.	o
Field	nnp	b-person
names	vbz	o
may	md	o
be	vb	o
specified	vbn	o
explicitly	rb	o
(	(	o
IdentifierList	nnp	o
)	)	o
or	cc	o
implicitly	rb	o
(	(	o
EmbeddedField	nnp	b-gpe
)	)	o
.	.	o
Within	in	o
a	dt	o
struct	nn	o
,	,	o
non-blank	jj	o
field	nn	o
names	vbz	o
must	md	o
be	vb	o
unique	jj	o
.	.	o
A	dt	o
field	nn	o
declared	vbn	o
with	in	o
a	dt	o
type	nn	o
but	cc	o
no	dt	o
explicit	jj	o
field	nn	o
name	nn	o
is	vbz	o
called	vbd	o
an	dt	o
embedded	jj	o
field	nn	o
.	.	o
An	dt	o
embedded	jj	o
field	nn	o
must	md	o
be	vb	o
specified	vbn	o
as	in	o
a	dt	o
type	nn	o
name	nn	o
or	cc	o
as	in	o
a	dt	o
pointer	nn	o
to	to	o
a	dt	o
non-interface	jj	o
type	nn	o
name	nn	o
,	,	o
and	cc	o
itself	prp	o
may	md	o
not	rb	o
be	vb	o
a	dt	o
pointer	nn	o
type	nn	o
.	.	o
The	dt	o
unqualified	jj	o
type	nn	o
name	nn	o
acts	vbz	o
as	in	o
the	dt	o
field	nn	o
name	nn	o
.	.	o
The	dt	o
following	vbg	o
declaration	nn	o
is	vbz	o
illegal	jj	o
because	in	o
field	nn	o
names	vbz	o
must	md	o
be	vb	o
unique	jj	o
in	in	o
a	dt	o
struct	nn	o
type	nn	o
:	:	o
A	dt	o
field	nn	o
or	cc	o
method	nn	o
of	in	o
an	dt	o
embedded	jj	o
field	nn	o
in	in	o
a	dt	o
struct	nn	o
is	vbz	o
called	vbd	o
promoted	vbn	o
if	in	o
is	vbz	o
a	dt	o
legal	jj	o
selector	nn	o
that	wdt	o
denotes	vbz	o
that	wdt	o
field	nn	o
or	cc	o
method	nn	o
.	.	o
Promoted	vbn	o
fields	nns	o
act	vbp	o
like	in	o
ordinary	jj	o
fields	nns	o
of	in	o
a	dt	o
struct	nn	o
except	vb	o
that	wdt	o
they	prp	o
cannot	vbp	o
be	vb	o
used	vbn	o
as	in	o
field	nn	o
names	vbz	o
in	in	o
composite	jj	o
literals	nns	o
of	in	o
the	dt	o
struct	nn	o
.	.	o
Given	vbn	o
a	dt	o
struct	nn	o
type	nn	o
and	cc	o
a	dt	o
defined	vbn	o
type	nn	o
,	,	o
promoted	vbn	o
methods	nns	o
are	vbp	o
included	vbn	o
in	in	o
the	dt	o
method	nn	o
set	nn	o
of	in	o
the	dt	o
struct	nn	o
as	in	o
follows	vbz	o
:	:	o
If	in	o
contains	vbz	o
an	dt	o
embedded	jj	o
field	nn	o
,	,	o
the	dt	o
method	nn	o
sets	vbz	o
of	in	o
and	cc	o
both	dt	o
include	vb	o
promoted	vbn	o
methods	nns	o
with	in	o
receiver	nn	o
.	.	o
The	dt	o
method	nn	o
set	nn	o
of	in	o
also	rb	o
includes	vbz	o
promoted	vbn	o
methods	nns	o
with	in	o
receiver	nn	o
.	.	o
If	in	o
contains	vbz	o
an	dt	o
embedded	jj	o
field	nn	o
,	,	o
the	dt	o
method	nn	o
sets	vbz	o
of	in	o
and	cc	o
both	dt	o
include	vb	o
promoted	vbn	o
methods	nns	o
with	in	o
receiver	nn	o
or	cc	o
.	.	o
A	dt	o
field	nn	o
declaration	nn	o
may	md	o
be	vb	o
followed	vbn	o
by	in	o
an	dt	o
optional	jj	o
string	vbg	o
literal	nn	o
tag	nn	o
,	,	o
which	wdt	o
becomes	vbz	o
an	dt	o
attribute	nn	o
for	in	o
all	pdt	o
the	dt	o
fields	nns	o
in	in	o
the	dt	o
corresponding	jj	o
field	nn	o
declaration	nn	o
.	.	o
An	dt	o
empty	jj	o
tag	nn	o
string	vbg	o
is	vbz	o
equivalent	jj	o
to	to	o
an	dt	o
absent	jj	o
tag	nn	o
.	.	o
The	dt	o
tags	nns	o
are	vbp	o
made	vbn	o
visible	jj	o
through	in	o
a	dt	o
reflection	nn	o
interface	nn	o
and	cc	o
take	vb	o
part	nn	o
in	in	o
type	nn	o
identity	nn	o
for	in	o
structs	nns	o
but	cc	o
are	vbp	o
otherwise	rb	o
ignored	vbn	o
.	.	o
Pointer	nnp	o
types	nns	o
A	dt	o
pointer	nn	o
type	nn	o
denotes	vbz	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
pointers	nns	o
to	to	o
variables	nns	o
of	in	o
a	dt	o
given	vbn	o
type	nn	o
,	,	o
called	vbd	o
the	dt	o
base	nn	o
type	nn	o
of	in	o
the	dt	o
pointer	nn	o
.	.	o
The	dt	o
value	nn	o
of	in	o
an	dt	o
uninitialized	jj	o
pointer	nn	o
is	vbz	o
.	.	o
Function	nnp	b-person
types	nns	o
A	dt	o
function	nn	o
type	nn	o
denotes	vbz	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
functions	nns	o
with	in	o
the	dt	o
same	jj	o
parameter	nn	o
and	cc	o
result	nn	o
types	nns	o
.	.	o
The	dt	o
value	nn	o
of	in	o
an	dt	o
uninitialized	jj	o
variable	nn	o
of	in	o
function	nn	o
type	nn	o
is	vbz	o
.	.	o
Within	in	o
a	dt	o
list	nn	o
of	in	o
parameters	nns	o
or	cc	o
results	nns	o
,	,	o
the	dt	o
names	vbz	o
(	(	o
IdentifierList	nnp	o
)	)	o
must	md	o
either	dt	o
all	pdt	o
be	vb	o
present	vb	o
or	cc	o
all	pdt	o
be	vb	o
absent	vbn	o
.	.	o
If	in	o
present	jj	o
,	,	o
each	dt	o
name	nn	o
stands	vbz	o
for	in	o
one	nn	o
item	nn	o
(	(	o
parameter	nn	o
or	cc	o
result	nn	o
)	)	o
of	in	o
the	dt	o
specified	vbn	o
type	nn	o
and	cc	o
all	pdt	o
non-blank	jj	o
names	vbz	o
in	in	o
the	dt	o
signature	nn	o
must	md	o
be	vb	o
unique	jj	o
.	.	o
If	in	o
absent	jj	o
,	,	o
each	dt	o
type	nn	o
stands	vbz	o
for	in	o
one	nn	o
item	nn	o
of	in	o
that	wdt	o
type	nn	o
.	.	o
Parameter	nnp	b-person
and	cc	o
result	nn	o
lists	nns	o
are	vbp	o
always	rb	o
parenthesized	vbn	o
except	vb	o
that	wdt	o
if	in	o
there	ex	o
is	vbz	o
exactly	rb	o
one	nn	o
unnamed	jj	o
result	nn	o
it	prp	o
may	md	o
be	vb	o
written	vbn	o
as	in	o
an	dt	o
unparenthesized	jj	o
type	nn	o
.	.	o
The	dt	o
final	jj	o
incoming	nn	o
parameter	nn	o
in	in	o
a	dt	o
function	nn	o
signature	nn	o
may	md	o
have	vb	o
a	dt	o
type	nn	o
prefixed	vbn	o
with	in	o
.	.	o
A	dt	o
function	nn	o
with	in	o
such	jj	o
a	dt	o
parameter	nn	o
is	vbz	o
called	vbd	o
variadic	jj	o
and	cc	o
may	md	o
be	vb	o
invoked	vbn	o
with	in	o
zero	nn	o
or	cc	o
more	jjr	o
arguments	nns	o
for	in	o
that	wdt	o
parameter	nn	o
.	.	o
Interface	nnp	o
types	nns	o
An	dt	o
interface	nn	o
type	nn	o
defines	vbz	o
a	dt	o
type	nn	o
set	nn	o
.	.	o
A	dt	o
variable	nn	o
of	in	o
interface	nn	o
type	nn	o
can	md	o
store	vb	o
a	dt	o
value	nn	o
of	in	o
any	dt	o
type	nn	o
that	wdt	o
is	vbz	o
in	in	o
the	dt	o
type	nn	o
set	nn	o
of	in	o
the	dt	o
interface	nn	o
.	.	o
Such	jj	o
a	dt	o
type	nn	o
is	vbz	o
said	vbd	o
to	to	o
implement	vb	o
the	dt	o
interface	nn	o
.	.	o
The	dt	o
value	nn	o
of	in	o
an	dt	o
uninitialized	jj	o
variable	nn	o
of	in	o
interface	nn	o
type	nn	o
is	vbz	o
.	.	o
An	dt	o
interface	nn	o
type	nn	o
is	vbz	o
specified	vbn	o
by	in	o
a	dt	o
list	nn	o
of	in	o
interface	nn	o
elements	nns	o
.	.	o
An	dt	o
interface	nn	o
element	nn	o
is	vbz	o
either	dt	o
a	dt	o
method	nn	o
or	cc	o
a	dt	o
type	nn	o
element	nn	o
,	,	o
where	wrb	o
a	dt	o
type	nn	o
element	nn	o
is	vbz	o
a	dt	o
union	nn	o
of	in	o
one	nn	o
or	cc	o
more	jjr	o
type	nn	o
terms	nns	o
.	.	o
A	dt	o
type	nn	o
term	nn	o
is	vbz	o
either	dt	o
a	dt	o
single	jj	o
type	nn	o
or	cc	o
a	dt	o
single	jj	o
underlying	jj	o
type	nn	o
.	.	o
Basic	jj	o
interfaces	nns	o
In	in	o
its	prp$	o
most	jjs	o
basic	jj	o
form	nn	o
an	dt	o
interface	nn	o
specifies	vbz	o
a	dt	o
(	(	o
possibly	rb	o
empty	rb	o
)	)	o
list	nn	o
of	in	o
methods	nns	o
.	.	o
The	dt	o
type	nn	o
set	nn	o
defined	vbn	o
by	in	o
such	jj	o
an	dt	o
interface	nn	o
is	vbz	o
the	dt	o
set	nn	o
of	in	o
types	nns	o
which	wdt	o
implement	vb	o
all	pdt	o
of	in	o
those	dt	o
methods	nns	o
,	,	o
and	cc	o
the	dt	o
corresponding	jj	o
method	nn	o
set	nn	o
consists	vbz	o
exactly	rb	o
of	in	o
the	dt	o
methods	nns	o
specified	vbn	o
by	in	o
the	dt	o
interface	nn	o
.	.	o
Interfaces	nns	o
whose	wp$	o
type	nn	o
sets	vbz	o
can	md	o
be	vb	o
defined	vbn	o
entirely	rb	o
by	in	o
a	dt	o
list	nn	o
of	in	o
methods	nns	o
are	vbp	o
called	vbd	o
basic	jj	o
interfaces	nns	o
.	.	o
The	dt	o
name	nn	o
of	in	o
each	dt	o
explicitly	rb	o
specified	vbn	o
method	nn	o
must	md	o
be	vb	o
unique	jj	o
and	cc	o
not	rb	o
blank	jj	o
.	.	o
More	rbr	o
than	in	o
one	nn	o
type	nn	o
may	md	o
implement	vb	o
an	dt	o
interface	nn	o
.	.	o
For	in	o
instance	nn	o
,	,	o
if	in	o
two	cd	o
types	nns	o
and	cc	o
have	vb	o
the	dt	o
method	nn	o
set	nn	o
(	(	o
where	wrb	o
stands	vbz	o
for	in	o
either	dt	o
or	cc	o
)	)	o
then	rb	o
the	dt	o
interface	nn	o
is	vbz	o
implemented	vbd	o
by	in	o
both	dt	o
and	cc	o
,	,	o
regardless	rb	o
of	in	o
what	wp	o
other	jj	o
methods	nns	o
and	cc	o
may	md	o
have	vb	o
or	cc	o
share	nn	o
.	.	o
Every	dt	o
type	nn	o
that	wdt	o
is	vbz	o
a	dt	o
member	nn	o
of	in	o
the	dt	o
type	nn	o
set	nn	o
of	in	o
an	dt	o
interface	nn	o
implements	vbz	o
that	wdt	o
interface	nn	o
.	.	o
Any	dt	o
given	vbn	o
type	nn	o
may	md	o
implement	vb	o
several	jj	o
distinct	jj	o
interfaces	nns	o
.	.	o
For	in	o
instance	nn	o
,	,	o
all	pdt	o
types	nns	o
implement	vb	o
the	dt	o
empty	jj	o
interface	nn	o
which	wdt	o
stands	vbz	o
for	in	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
types	nns	o
:	:	o
For	in	o
convenience	nn	o
,	,	o
the	dt	o
predeclared	jj	o
type	nn	o
is	vbz	o
an	dt	o
alias	nn	o
for	in	o
the	dt	o
empty	jj	o
interface	nn	o
.	.	o
Similarly	rb	o
,	,	o
consider	vb	o
this	dt	o
interface	nn	o
specification	nn	o
,	,	o
which	wdt	o
appears	vbz	o
within	in	o
a	dt	o
type	nn	o
declaration	nn	o
to	to	o
define	vb	o
an	dt	o
interface	nn	o
called	vbd	o
:	:	o
If	in	o
and	cc	o
also	rb	o
implement	vb	o
they	prp	o
implement	vb	o
the	dt	o
interface	nn	o
as	in	o
well	rb	o
as	in	o
the	dt	o
interface	nn	o
.	.	o
Embedded	jj	o
interfaces	nns	o
In	in	o
a	dt	o
slightly	rb	o
more	jjr	o
general	jj	o
form	nn	o
an	dt	o
interface	nn	o
may	md	o
use	vbp	o
a	dt	o
(	(	o
possibly	rb	o
qualified	vbn	o
)	)	o
interface	nn	o
type	nn	o
name	nn	o
as	in	o
an	dt	o
interface	nn	o
element	nn	o
.	.	o
This	dt	o
is	vbz	o
called	vbd	o
embedding	vbg	o
interface	nn	o
in	in	o
.	.	o
The	dt	o
type	nn	o
set	nn	o
of	in	o
is	vbz	o
the	dt	o
intersection	nn	o
of	in	o
the	dt	o
type	nn	o
sets	vbz	o
defined	vbn	o
by	in	o
's	pos	o
explicitly	rb	o
declared	vbn	o
methods	nns	o
and	cc	o
the	dt	o
type	nn	o
sets	vbz	o
of	in	o
's	pos	o
embedded	jj	o
interfaces	nns	o
.	.	o
In	in	o
other	jj	o
words	nns	o
,	,	o
the	dt	o
type	nn	o
set	nn	o
of	in	o
is	vbz	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
types	nns	o
that	wdt	o
implement	vb	o
all	pdt	o
the	dt	o
explicitly	rb	o
declared	vbn	o
methods	nns	o
of	in	o
and	cc	o
also	rb	o
all	pdt	o
the	dt	o
methods	nns	o
of	in	o
.	.	o
When	wrb	o
embedding	vbg	o
interfaces	nns	o
,	,	o
methods	nns	o
with	in	o
the	dt	o
same	jj	o
names	vbz	o
must	md	o
have	vb	o
identical	jj	o
signatures	nns	o
.	.	o
General	jj	o
interfaces	nns	o
In	in	o
their	prp$	o
most	jjs	o
general	jj	o
form	nn	o
,	,	o
an	dt	o
interface	nn	o
element	nn	o
may	md	o
also	rb	o
be	vb	o
an	dt	o
arbitrary	jj	o
type	nn	o
term	nn	o
,	,	o
or	cc	o
a	dt	o
term	nn	o
of	in	o
the	dt	o
form	nn	o
specifying	vbg	o
the	dt	o
underlying	jj	o
type	nn	o
,	,	o
or	cc	o
a	dt	o
union	nn	o
of	in	o
terms	nns	o
.	.	o
Together	rb	o
with	in	o
method	nn	o
specifications	nns	o
,	,	o
these	dt	o
elements	nns	o
enable	vbp	o
the	dt	o
precise	jj	o
definition	nn	o
of	in	o
an	dt	o
interface	nn	o
's	pos	o
type	nn	o
set	nn	o
as	in	o
follows	vbz	o
:	:	o
The	dt	o
type	nn	o
set	nn	o
of	in	o
the	dt	o
empty	jj	o
interface	nn	o
is	vbz	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
non-interface	jj	o
types	nns	o
.	.	o
The	dt	o
type	nn	o
set	nn	o
of	in	o
a	dt	o
non-empty	jj	o
interface	nn	o
is	vbz	o
the	dt	o
intersection	nn	o
of	in	o
the	dt	o
type	nn	o
sets	vbz	o
of	in	o
its	prp$	o
interface	nn	o
elements	nns	o
.	.	o
The	dt	o
type	nn	o
set	nn	o
of	in	o
a	dt	o
method	nn	o
specification	nn	o
is	vbz	o
the	dt	o
set	nn	o
of	in	o
types	nns	o
whose	wp$	o
method	nn	o
sets	vbz	o
include	vb	o
that	wdt	o
method	nn	o
.	.	o
The	dt	o
type	nn	o
set	nn	o
of	in	o
a	dt	o
non-interface	jj	o
type	nn	o
term	nn	o
is	vbz	o
the	dt	o
set	nn	o
consisting	nn	o
of	in	o
just	rb	o
that	wdt	o
type	nn	o
.	.	o
The	dt	o
type	nn	o
set	nn	o
of	in	o
a	dt	o
term	nn	o
of	in	o
the	dt	o
form	nn	o
is	vbz	o
the	dt	o
set	nn	o
of	in	o
types	nns	o
whose	wp$	o
underlying	jj	o
type	nn	o
is	vbz	o
.	.	o
The	dt	o
type	nn	o
set	nn	o
of	in	o
a	dt	o
union	nn	o
of	in	o
terms	nns	o
is	vbz	o
the	dt	o
union	nn	o
of	in	o
the	dt	o
type	nn	o
sets	vbz	o
of	in	o
the	dt	o
terms	nns	o
.	.	o
By	in	o
construction	nn	o
,	,	o
an	dt	o
interface	nn	o
's	pos	o
type	nn	o
set	nn	o
never	rb	o
contains	vbz	o
an	dt	o
interface	nn	o
type	nn	o
.	.	o
In	in	o
a	dt	o
term	nn	o
of	in	o
the	dt	o
form	nn	o
,	,	o
the	dt	o
underlying	jj	o
type	nn	o
of	in	o
must	md	o
be	vb	o
itself	prp	o
,	,	o
and	cc	o
cannot	vbp	o
be	vb	o
an	dt	o
interface	nn	o
.	.	o
Union	nnp	o
elements	nns	o
denote	vbp	o
unions	nns	o
of	in	o
type	nn	o
sets	nns	o
:	:	o
In	in	o
a	dt	o
union	nn	o
,	,	o
a	dt	o
term	nn	o
cannot	vbp	o
be	vb	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
and	cc	o
the	dt	o
type	nn	o
sets	vbz	o
of	in	o
all	pdt	o
non-interface	jj	o
terms	nns	o
must	md	o
be	vb	o
pairwise	nn	o
disjoint	nn	o
(	(	o
the	dt	o
pairwise	nn	o
intersection	nn	o
of	in	o
the	dt	o
type	nn	o
sets	vbz	o
must	md	o
be	vb	o
empty	jj	o
)	)	o
.	.	o
Given	vbn	o
a	dt	o
type	nn	o
parameter	nn	o
:	:	o
Implementation	nnp	o
restriction	nn	o
:	:	o
A	dt	o
union	nn	o
with	in	o
more	jjr	o
than	in	o
one	nn	o
term	nn	o
cannot	vbp	o
contain	vb	o
the	dt	o
predeclared	jj	o
identifier	nn	o
or	cc	o
interfaces	nns	o
that	wdt	o
specify	vb	o
methods	nns	o
,	,	o
or	cc	o
embed	nn	o
or	cc	o
interfaces	nns	o
that	wdt	o
specify	vb	o
methods	nns	o
.	.	o
Interfaces	nns	o
that	wdt	o
are	vbp	o
not	rb	o
basic	jj	o
may	md	o
only	rb	o
be	vb	o
used	vbn	o
as	in	o
type	nn	o
constraints	nns	o
,	,	o
or	cc	o
as	in	o
elements	nns	o
of	in	o
other	jj	o
interfaces	nns	o
used	vbn	o
as	in	o
constraints	nns	o
.	.	o
They	prp	o
cannot	vbp	o
be	vb	o
the	dt	o
types	nns	o
of	in	o
values	nns	o
or	cc	o
variables	nns	o
,	,	o
or	cc	o
components	nns	o
of	in	o
other	jj	o
,	,	o
non-interface	jj	o
types	nns	o
.	.	o
An	dt	o
interface	nn	o
type	nn	o
may	md	o
not	rb	o
embed	nn	o
any	dt	o
type	nn	o
element	nn	o
that	wdt	o
is	vbz	o
,	,	o
contains	nns	o
,	,	o
or	cc	o
embeds	nns	o
,	,	o
recursively	rb	o
.	.	o
Implementing	vbg	o
an	dt	o
interface	nn	o
A	dt	o
type	nn	o
implements	vbz	o
an	dt	o
interface	nn	o
if	in	o
is	vbz	o
not	rb	o
an	dt	o
interface	nn	o
and	cc	o
is	vbz	o
an	dt	o
element	nn	o
of	in	o
the	dt	o
type	nn	o
set	nn	o
of	in	o
;	:	o
or	cc	o
is	vbz	o
an	dt	o
interface	nn	o
and	cc	o
the	dt	o
type	nn	o
set	nn	o
of	in	o
is	vbz	o
a	dt	o
subset	nn	o
of	in	o
the	dt	o
type	nn	o
set	nn	o
of	in	o
.	.	o
A	dt	o
value	nn	o
of	in	o
type	nn	o
implements	vbz	o
an	dt	o
interface	nn	o
if	in	o
implements	vbz	o
the	dt	o
interface	nn	o
.	.	o
Map	nnp	o
types	nns	o
A	dt	o
map	nn	o
is	vbz	o
an	dt	o
unordered	jj	o
group	nn	o
of	in	o
elements	nns	o
of	in	o
one	nn	o
type	nn	o
,	,	o
called	vbd	o
the	dt	o
element	nn	o
type	nn	o
,	,	o
indexed	vbn	o
by	in	o
a	dt	o
set	nn	o
of	in	o
unique	jj	o
keys	nns	o
of	in	o
another	dt	o
type	nn	o
,	,	o
called	vbd	o
the	dt	o
key	nn	o
type	nn	o
.	.	o
The	dt	o
value	nn	o
of	in	o
an	dt	o
uninitialized	jj	o
map	nn	o
is	vbz	o
.	.	o
The	dt	o
comparison	nn	o
operators	nns	o
and	cc	o
must	md	o
be	vb	o
fully	rb	o
defined	vbn	o
for	in	o
operands	nns	o
of	in	o
the	dt	o
key	nn	o
type	nn	o
;	:	o
thus	rb	o
the	dt	o
key	nn	o
type	nn	o
must	md	o
not	rb	o
be	vb	o
a	dt	o
function	nn	o
,	,	o
map	nn	o
,	,	o
or	cc	o
slice	nn	o
.	.	o
If	in	o
the	dt	o
key	nn	o
type	nn	o
is	vbz	o
an	dt	o
interface	nn	o
type	nn	o
,	,	o
these	dt	o
comparison	nn	o
operators	nns	o
must	md	o
be	vb	o
defined	vbn	o
for	in	o
the	dt	o
dynamic	jj	o
key	nn	o
values	nns	o
;	:	o
failure	nn	o
will	md	o
cause	vb	o
a	dt	o
run-time	jj	o
panic	nn	o
.	.	o
The	dt	o
number	nn	o
of	in	o
map	nn	o
elements	nns	o
is	vbz	o
called	vbd	o
its	prp$	o
length	nn	o
.	.	o
For	in	o
a	dt	o
map	nn	o
,	,	o
it	prp	o
can	md	o
be	vb	o
discovered	vbn	o
using	vbg	o
the	dt	o
built-in	jj	o
function	nn	o
and	cc	o
may	md	o
change	vbp	o
during	in	o
execution	nn	o
.	.	o
Elements	nns	o
may	md	o
be	vb	o
added	vbn	o
during	in	o
execution	nn	o
using	vbg	o
assignments	nns	o
and	cc	o
retrieved	vbn	o
with	in	o
index	nn	o
expressions	nns	o
;	:	o
they	prp	o
may	md	o
be	vb	o
removed	vbn	o
with	in	o
the	dt	o
built-in	jj	o
function	nn	o
.	.	o
A	dt	o
new	jj	o
,	,	o
empty	jj	o
map	nn	o
value	nn	o
is	vbz	o
made	vbn	o
using	vbg	o
the	dt	o
built-in	jj	o
function	nn	o
,	,	o
which	wdt	o
takes	vbz	o
the	dt	o
map	nn	o
type	nn	o
and	cc	o
an	dt	o
optional	jj	o
capacity	nn	o
hint	nn	o
as	in	o
arguments	nns	o
:	:	o
The	dt	o
initial	jj	o
capacity	nn	o
does	vbz	o
not	rb	o
bound	vbn	o
its	prp$	o
size	nn	o
:	:	o
maps	nns	o
grow	vb	o
to	to	o
accommodate	vb	o
the	dt	o
number	nn	o
of	in	o
items	nns	o
stored	vbn	o
in	in	o
them	prp	o
,	,	o
with	in	o
the	dt	o
exception	nn	o
of	in	o
maps	nns	o
.	.	o
A	dt	o
map	nn	o
is	vbz	o
equivalent	jj	o
to	to	o
an	dt	o
empty	jj	o
map	nn	o
except	vb	o
that	wdt	o
no	dt	o
elements	nns	o
may	md	o
be	vb	o
added	vbn	o
.	.	o
Channel	nnp	o
types	nns	o
A	dt	o
channel	nns	o
provides	vbz	o
a	dt	o
mechanism	nn	o
for	in	o
concurrently	rb	o
executing	vbg	o
functions	nns	o
to	to	o
communicate	vb	o
by	in	o
sending	vbg	o
and	cc	o
receiving	vbg	o
values	nns	o
of	in	o
a	dt	o
specified	vbn	o
element	nn	o
type	nn	o
.	.	o
The	dt	o
value	nn	o
of	in	o
an	dt	o
uninitialized	jj	o
channel	nns	o
is	vbz	o
.	.	o
The	dt	o
optional	jj	o
operator	nn	o
specifies	vbz	o
the	dt	o
channel	nns	o
direction	nn	o
,	,	o
send	vb	o
or	cc	o
receive	vbp	o
.	.	o
If	in	o
a	dt	o
direction	nn	o
is	vbz	o
given	vbn	o
,	,	o
the	dt	o
channel	nns	o
is	vbz	o
directional	jj	o
,	,	o
otherwise	rb	o
it	prp	o
is	vbz	o
bidirectional	jj	o
.	.	o
A	dt	o
channel	nns	o
may	md	o
be	vb	o
constrained	vbn	o
only	rb	o
to	to	o
send	vb	o
or	cc	o
only	rb	o
to	to	o
receive	nn	o
by	in	o
assignment	nn	o
or	cc	o
explicit	jj	o
conversion	nn	o
.	.	o
The	dt	o
operator	nn	o
associates	vbz	o
with	in	o
the	dt	o
leftmost	nn	o
possible	jj	o
:	:	o
A	dt	o
new	jj	o
,	,	o
initialized	vbn	o
channel	nns	o
value	nn	o
can	md	o
be	vb	o
made	vbn	o
using	vbg	o
the	dt	o
built-in	jj	o
function	nn	o
,	,	o
which	wdt	o
takes	vbz	o
the	dt	o
channel	nns	o
type	nn	o
and	cc	o
an	dt	o
optional	jj	o
capacity	nn	o
as	in	o
arguments	nns	o
:	:	o
The	dt	o
capacity	nn	o
,	,	o
in	in	o
number	nn	o
of	in	o
elements	nns	o
,	,	o
sets	vbz	o
the	dt	o
size	nn	o
of	in	o
the	dt	o
buffer	nn	o
in	in	o
the	dt	o
channel	nn	o
.	.	o
If	in	o
the	dt	o
capacity	nn	o
is	vbz	o
zero	nn	o
or	cc	o
absent	jj	o
,	,	o
the	dt	o
channel	nns	o
is	vbz	o
unbuffered	jj	o
and	cc	o
communication	nn	o
succeeds	vbz	o
only	rb	o
when	wrb	o
both	dt	o
a	dt	o
sender	nn	o
and	cc	o
receiver	nn	o
are	vbp	o
ready	jj	o
.	.	o
Otherwise	rb	o
,	,	o
the	dt	o
channel	nns	o
is	vbz	o
buffered	vbd	o
and	cc	o
communication	nn	o
succeeds	vbz	o
without	in	o
blocking	vbg	o
if	in	o
the	dt	o
buffer	nn	o
is	vbz	o
not	rb	o
full	jj	o
(	(	o
sends	nns	o
)	)	o
or	cc	o
not	rb	o
empty	jj	o
(	(	o
receives	nns	o
)	)	o
.	.	o
A	dt	o
channel	nns	o
is	vbz	o
never	rb	o
ready	vbp	o
for	in	o
communication	nn	o
.	.	o
A	dt	o
channel	nns	o
may	md	o
be	vb	o
closed	jj	o
with	in	o
the	dt	o
built-in	jj	o
function	nn	o
.	.	o
The	dt	o
multi-valued	jj	o
assignment	nn	o
form	nn	o
of	in	o
the	dt	o
receive	nn	o
operator	nn	o
reports	vbz	o
whether	in	o
a	dt	o
received	jj	o
value	nn	o
was	vbd	o
sent	vbn	o
before	in	o
the	dt	o
channel	nns	o
was	vbd	o
closed	vbn	o
.	.	o
A	dt	o
single	jj	o
channel	nns	o
may	md	o
be	vb	o
used	vbn	o
in	in	o
send	vb	o
statements	nns	o
,	,	o
receive	nn	o
operations	nns	o
,	,	o
and	cc	o
calls	vbz	o
to	to	o
the	dt	o
built-in	jj	o
functions	nns	o
and	cc	o
by	in	o
any	dt	o
number	nn	o
of	in	o
goroutines	nns	o
without	in	o
further	jj	o
synchronization	nn	o
.	.	o
Channels	nnp	o
act	vbp	o
as	in	o
first-in-first-out	jj	o
queues	nns	o
.	.	o
For	in	o
example	nn	o
,	,	o
if	in	o
one	nn	o
goroutine	nn	o
sends	vbz	o
values	nns	o
on	in	o
a	dt	o
channel	nns	o
and	cc	o
a	dt	o
second	jj	o
goroutine	nn	o
receives	nns	o
them	prp	o
,	,	o
the	dt	o
values	nns	o
are	vbp	o
received	jj	o
in	in	o
the	dt	o
order	nn	o
sent	nn	o
.	.	o
Properties	nns	o
of	in	o
types	nns	o
and	cc	o
values	nns	o
Underlying	vbg	o
types	nns	o
Each	dt	o
type	nn	o
has	vbz	o
an	dt	o
underlying	jj	o
type	nn	o
:	:	o
If	in	o
is	vbz	o
one	nn	o
of	in	o
the	dt	o
predeclared	jj	o
boolean	nn	o
,	,	o
numeric	jj	o
,	,	o
or	cc	o
string	vbg	o
types	nns	o
,	,	o
or	cc	o
a	dt	o
type	nn	o
literal	jj	o
,	,	o
the	dt	o
corresponding	jj	o
underlying	jj	o
type	nn	o
is	vbz	o
itself	prp	o
.	.	o
Otherwise	rb	o
,	,	o
's	pos	o
underlying	jj	o
type	nn	o
is	vbz	o
the	dt	o
underlying	jj	o
type	nn	o
of	in	o
the	dt	o
type	nn	o
to	to	o
which	wdt	o
refers	nns	o
in	in	o
its	prp$	o
type	nn	o
declaration	nn	o
.	.	o
The	dt	o
underlying	jj	o
type	nn	o
of	in	o
a	dt	o
type	nn	o
parameter	nn	o
is	vbz	o
the	dt	o
underlying	jj	o
type	nn	o
of	in	o
its	prp$	o
type	nn	o
constraint	nn	o
,	,	o
which	wdt	o
is	vbz	o
always	rb	o
an	dt	o
interface	nn	o
.	.	o
The	dt	o
underlying	jj	o
type	nn	o
of	in	o
,	,	o
,	,	o
,	,	o
,	,	o
and	cc	o
is	vbz	o
.	.	o
The	dt	o
underlying	jj	o
type	nn	o
of	in	o
,	,	o
,	,	o
and	cc	o
is	vbz	o
.	.	o
The	dt	o
underlying	jj	o
type	nn	o
of	in	o
is	vbz	o
.	.	o
Core	nnp	b-gpe
types	nns	o
Each	dt	o
non-interface	jj	o
type	nn	o
has	vbz	o
a	dt	o
core	nn	o
type	nn	o
,	,	o
which	wdt	o
is	vbz	o
the	dt	o
same	jj	o
as	in	o
the	dt	o
underlying	jj	o
type	nn	o
of	in	o
.	.	o
An	dt	o
interface	nn	o
has	vbz	o
a	dt	o
core	nn	o
type	nn	o
if	in	o
one	nn	o
of	in	o
the	dt	o
following	vbg	o
conditions	nns	o
is	vbz	o
satisfied	jj	o
:	:	o
There	ex	o
is	vbz	o
a	dt	o
single	jj	o
type	nn	o
which	wdt	o
is	vbz	o
the	dt	o
underlying	jj	o
type	nn	o
of	in	o
all	pdt	o
types	nns	o
in	in	o
the	dt	o
type	nn	o
set	nn	o
of	in	o
;	:	o
or	cc	o
the	dt	o
type	nn	o
set	nn	o
of	in	o
contains	vbz	o
only	rb	o
channel	nns	o
types	nns	o
with	in	o
identical	jj	o
element	nn	o
type	nn	o
,	,	o
and	cc	o
all	pdt	o
directional	jj	o
channels	vb	o
have	vb	o
the	dt	o
same	jj	o
direction	nn	o
.	.	o
All	dt	o
other	jj	o
interfaces	nns	o
do	vbp	o
n't	rb	o
have	vb	o
a	dt	o
core	nn	o
type	nn	o
.	.	o
The	dt	o
core	nn	o
type	nn	o
of	in	o
an	dt	o
interface	nn	o
is	vbz	o
,	,	o
depending	vbg	o
on	in	o
the	dt	o
condition	nn	o
that	wdt	o
is	vbz	o
satisfied	jj	o
,	,	o
either	dt	o
:	:	o
the	dt	o
type	nn	o
;	:	o
or	cc	o
the	dt	o
type	nn	o
if	in	o
contains	vbz	o
only	rb	o
bidirectional	jj	o
channels	nns	o
,	,	o
or	cc	o
the	dt	o
type	nn	o
or	cc	o
depending	vbg	o
on	in	o
the	dt	o
direction	nn	o
of	in	o
the	dt	o
directional	jj	o
channels	vb	o
present	jj	o
.	.	o
By	in	o
definition	nn	o
,	,	o
a	dt	o
core	nn	o
type	nn	o
is	vbz	o
never	rb	o
a	dt	o
defined	vbn	o
type	nn	o
,	,	o
type	nn	o
parameter	nn	o
,	,	o
or	cc	o
interface	nn	o
type	nn	o
.	.	o
Examples	nns	o
of	in	o
interfaces	nns	o
with	in	o
core	nn	o
types	nns	o
:	:	o
Examples	nns	o
of	in	o
interfaces	nns	o
whithout	in	o
core	nn	o
types	nns	o
:	:	o
Specific	jj	o
types	nns	o
[	vbp	o
The	dt	o
definition	nn	o
of	in	o
specific	jj	o
types	nns	o
is	vbz	o
not	rb	o
quite	rb	o
correct	jj	o
yet	rb	o
.	.	o
]	vb	o
An	dt	o
interface	nn	o
specification	nn	o
that	wdt	o
contains	vbz	o
type	nn	o
elements	nns	o
defines	vbz	o
a	dt	o
(	(	o
possibly	rb	o
empty	rb	o
)	)	o
set	nn	o
of	in	o
specific	jj	o
types	nns	o
.	.	o
Loosely	rb	o
speaking	vbg	o
,	,	o
these	dt	o
are	vbp	o
the	dt	o
types	nns	o
that	wdt	o
appear	vbp	o
in	in	o
the	dt	o
interface	nn	o
definition	nn	o
in	in	o
terms	nns	o
of	in	o
the	dt	o
form	nn	o
,	,	o
,	,	o
or	cc	o
in	in	o
unions	nns	o
of	in	o
such	jj	o
terms	nns	o
.	.	o
More	rbr	o
precisely	rb	o
,	,	o
for	in	o
a	dt	o
given	vbn	o
interface	nn	o
,	,	o
the	dt	o
set	nn	o
of	in	o
specific	jj	o
types	nns	o
corresponds	vbz	o
to	to	o
the	dt	o
set	nn	o
𝑅	nn	o
of	in	o
representative	jj	o
types	nns	o
of	in	o
the	dt	o
interface	nn	o
,	,	o
if	in	o
𝑅	nn	o
is	vbz	o
non-empty	jj	o
and	cc	o
finite	jj	o
.	.	o
Otherwise	rb	o
,	,	o
if	in	o
𝑅	nn	o
is	vbz	o
empty	jj	o
or	cc	o
infinite	jj	o
,	,	o
the	dt	o
interface	nn	o
has	vbz	o
no	dt	o
specific	jj	o
types	nns	o
.	.	o
For	in	o
a	dt	o
given	vbn	o
interface	nn	o
,	,	o
type	nn	o
element	nn	o
or	cc	o
type	nn	o
term	nn	o
,	,	o
the	dt	o
set	nn	o
𝑅	nn	o
of	in	o
representative	jj	o
types	nns	o
is	vbz	o
defined	vbn	o
as	in	o
follows	vbz	o
:	:	o
For	in	o
an	dt	o
interface	nn	o
with	in	o
no	dt	o
type	nn	o
elements	nns	o
,	,	o
𝑅	nn	o
is	vbz	o
the	dt	o
(	(	o
infinite	jj	o
)	)	o
set	nn	o
of	in	o
all	pdt	o
types	nns	o
.	.	o
For	in	o
an	dt	o
interface	nn	o
with	in	o
type	nn	o
elements	nns	o
,	,	o
𝑅	nn	o
is	vbz	o
the	dt	o
intersection	nn	o
of	in	o
the	dt	o
representative	jj	o
types	nns	o
of	in	o
its	prp$	o
type	nn	o
elements	nns	o
.	.	o
For	in	o
a	dt	o
non-interface	jj	o
type	nn	o
term	nn	o
or	cc	o
a	dt	o
term	nn	o
of	in	o
the	dt	o
form	nn	o
,	,	o
𝑅	nn	o
is	vbz	o
the	dt	o
set	nn	o
consisting	nn	o
of	in	o
the	dt	o
type	nn	o
.	.	o
For	in	o
a	dt	o
union	nn	o
of	in	o
terms	nns	o
,	,	o
𝑅	nn	o
is	vbz	o
the	dt	o
union	nn	o
of	in	o
the	dt	o
representative	jj	o
types	nns	o
of	in	o
the	dt	o
terms	nns	o
.	.	o
An	dt	o
interface	nn	o
may	md	o
have	vb	o
specific	jj	o
types	nns	o
even	rb	o
if	in	o
its	prp$	o
type	nn	o
set	nn	o
is	vbz	o
empty	jj	o
.	.	o
Examples	nns	o
of	in	o
interfaces	nns	o
with	in	o
their	prp$	o
specific	jj	o
types	nns	o
:	:	o
Type	nnp	b-person
identity	nn	o
Two	cd	o
types	nns	o
are	vbp	o
either	dt	o
identical	jj	o
or	cc	o
different	jj	o
.	.	o
A	dt	o
named	vbn	o
type	nn	o
is	vbz	o
always	rb	o
different	jj	o
from	in	o
any	dt	o
other	jj	o
type	nn	o
.	.	o
Otherwise	rb	o
,	,	o
two	cd	o
types	nns	o
are	vbp	o
identical	jj	o
if	in	o
their	prp$	o
underlying	jj	o
type	nn	o
literals	nns	o
are	vbp	o
structurally	rb	o
equivalent	jj	o
;	:	o
that	wdt	o
is	vbz	o
,	,	o
they	prp	o
have	vb	o
the	dt	o
same	jj	o
literal	nn	o
structure	nn	o
and	cc	o
corresponding	jj	o
components	nns	o
have	vb	o
identical	jj	o
types	nns	o
.	.	o
In	in	o
detail	nn	o
:	:	o
Two	cd	o
array	nn	o
types	nns	o
are	vbp	o
identical	jj	o
if	in	o
they	prp	o
have	vb	o
identical	jj	o
element	nn	o
types	nns	o
and	cc	o
the	dt	o
same	jj	o
array	nn	o
length	nn	o
.	.	o
Two	cd	o
slice	nn	o
types	nns	o
are	vbp	o
identical	jj	o
if	in	o
they	prp	o
have	vb	o
identical	jj	o
element	nn	o
types	nns	o
.	.	o
Two	cd	o
struct	nn	o
types	nns	o
are	vbp	o
identical	jj	o
if	in	o
they	prp	o
have	vb	o
the	dt	o
same	jj	o
sequence	nn	o
of	in	o
fields	nns	o
,	,	o
and	cc	o
if	in	o
corresponding	jj	o
fields	nns	o
have	vb	o
the	dt	o
same	jj	o
names	nns	o
,	,	o
and	cc	o
identical	jj	o
types	nns	o
,	,	o
and	cc	o
identical	jj	o
tags	nns	o
.	.	o
Non-exported	jj	o
field	nn	o
names	vbz	o
from	in	o
different	jj	o
packages	nns	o
are	vbp	o
always	rb	o
different	jj	o
.	.	o
Two	cd	o
pointer	nn	o
types	nns	o
are	vbp	o
identical	jj	o
if	in	o
they	prp	o
have	vb	o
identical	jj	o
base	nn	o
types	nns	o
.	.	o
Two	cd	o
function	nn	o
types	nns	o
are	vbp	o
identical	jj	o
if	in	o
they	prp	o
have	vb	o
the	dt	o
same	jj	o
number	nn	o
of	in	o
parameters	nns	o
and	cc	o
result	nn	o
values	nns	o
,	,	o
corresponding	jj	o
parameter	nn	o
and	cc	o
result	nn	o
types	nns	o
are	vbp	o
identical	jj	o
,	,	o
and	cc	o
either	dt	o
both	dt	o
functions	nns	o
are	vbp	o
variadic	jj	o
or	cc	o
neither	cc	o
is	vbz	o
.	.	o
Parameter	nnp	b-person
and	cc	o
result	nn	o
names	vbz	o
are	vbp	o
not	rb	o
required	vbn	o
to	to	o
match	vb	o
.	.	o
Two	cd	o
interface	nn	o
types	nns	o
are	vbp	o
identical	jj	o
if	in	o
they	prp	o
define	vb	o
the	dt	o
same	jj	o
type	nn	o
set	nn	o
.	.	o
Two	cd	o
map	nn	o
types	nns	o
are	vbp	o
identical	jj	o
if	in	o
they	prp	o
have	vb	o
identical	jj	o
key	nn	o
and	cc	o
element	nn	o
types	nns	o
.	.	o
Two	cd	o
channel	nns	o
types	nns	o
are	vbp	o
identical	jj	o
if	in	o
they	prp	o
have	vb	o
identical	jj	o
element	nn	o
types	nns	o
and	cc	o
the	dt	o
same	jj	o
direction	nn	o
.	.	o
Two	cd	o
instantiated	vbn	o
types	nns	o
are	vbp	o
identical	jj	o
if	in	o
their	prp$	o
defined	vbn	o
types	nns	o
and	cc	o
all	pdt	o
type	nn	o
arguments	nns	o
are	vbp	o
identical	jj	o
.	.	o
Given	vbn	o
the	dt	o
declarations	nns	o
these	dt	o
types	nns	o
are	vbp	o
identical	jj	o
:	:	o
and	cc	o
are	vbp	o
different	jj	o
because	in	o
they	prp	o
are	vbp	o
new	jj	o
types	nns	o
created	vbn	o
by	in	o
distinct	jj	o
type	nn	o
definitions	nns	o
;	:	o
and	cc	o
are	vbp	o
different	jj	o
because	in	o
is	vbz	o
different	jj	o
from	in	o
;	:	o
and	cc	o
and	cc	o
are	vbp	o
different	jj	o
because	in	o
they	prp	o
are	vbp	o
different	jj	o
type	nn	o
parameters	nns	o
.	.	o
and	cc	o
are	vbp	o
different	jj	o
because	in	o
the	dt	o
former	jj	o
is	vbz	o
an	dt	o
instantiated	vbn	o
defined	vbn	o
type	nn	o
while	in	o
the	dt	o
latter	nn	o
is	vbz	o
a	dt	o
type	nn	o
literal	nn	o
(	(	o
but	cc	o
they	prp	o
are	vbp	o
still	rb	o
assignable	jj	o
)	)	o
.	.	o
Assignability	nnp	o
A	dt	o
value	nn	o
is	vbz	o
assignable	jj	o
to	to	o
a	dt	o
variable	nn	o
of	in	o
type	nn	o
(	(	o
"	nnp	o
is	vbz	o
assignable	jj	o
to	to	o
"	vb	o
)	)	o
if	in	o
one	nn	o
of	in	o
the	dt	o
following	vbg	o
conditions	nns	o
applies	nns	o
:	:	o
's	pos	o
type	nn	o
is	vbz	o
identical	jj	o
to	to	o
.	.	o
's	pos	o
type	nn	o
and	cc	o
have	vb	o
identical	jj	o
underlying	jj	o
types	nns	o
and	cc	o
at	in	o
least	jjs	o
one	nn	o
of	in	o
or	cc	o
is	vbz	o
not	rb	o
a	dt	o
named	vbn	o
type	nn	o
.	.	o
's	pos	o
type	nn	o
and	cc	o
are	vbp	o
channel	nns	o
types	nns	o
with	in	o
identical	jj	o
element	nn	o
types	nns	o
,	,	o
is	vbz	o
a	dt	o
bidirectional	jj	o
channel	nn	o
,	,	o
and	cc	o
at	in	o
least	jjs	o
one	nn	o
of	in	o
or	cc	o
is	vbz	o
not	rb	o
a	dt	o
named	vbn	o
type	nn	o
.	.	o
is	vbz	o
an	dt	o
interface	nn	o
type	nn	o
,	,	o
but	cc	o
not	rb	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
and	cc	o
implements	vbz	o
.	.	o
is	vbz	o
the	dt	o
predeclared	jj	o
identifier	nn	o
and	cc	o
is	vbz	o
a	dt	o
pointer	nn	o
,	,	o
function	nn	o
,	,	o
slice	nn	o
,	,	o
map	nn	o
,	,	o
channel	nn	o
,	,	o
or	cc	o
interface	nn	o
type	nn	o
,	,	o
but	cc	o
not	rb	o
a	dt	o
type	nn	o
parameter	nn	o
.	.	o
is	vbz	o
an	dt	o
untyped	jj	o
constant	nn	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
.	.	o
Additionally	rb	o
,	,	o
if	in	o
type	nn	o
or	cc	o
are	vbp	o
type	nn	o
parameters	nns	o
with	in	o
specific	jj	o
types	nns	o
,	,	o
is	vbz	o
assignable	jj	o
to	to	o
a	dt	o
variable	nn	o
of	in	o
type	nn	o
if	in	o
one	nn	o
of	in	o
the	dt	o
following	vbg	o
conditions	nns	o
applies	nns	o
:	:	o
is	vbz	o
the	dt	o
predeclared	jj	o
identifier	nn	o
,	,	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
and	cc	o
is	vbz	o
assignable	jj	o
to	to	o
each	dt	o
specific	jj	o
type	nn	o
of	in	o
.	.	o
is	vbz	o
not	rb	o
a	dt	o
named	vbn	o
type	nn	o
,	,	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
and	cc	o
is	vbz	o
assignable	jj	o
to	to	o
each	dt	o
specific	jj	o
type	nn	o
of	in	o
.	.	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
and	cc	o
is	vbz	o
not	rb	o
a	dt	o
named	vbn	o
type	nn	o
,	,	o
and	cc	o
values	nns	o
of	in	o
each	dt	o
specific	jj	o
type	nn	o
of	in	o
are	vbp	o
assignable	jj	o
to	to	o
.	.	o
Representability	nnp	o
A	dt	o
constant	nn	o
is	vbz	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
,	,	o
where	wrb	o
is	vbz	o
not	rb	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
if	in	o
one	nn	o
of	in	o
the	dt	o
following	vbg	o
conditions	nns	o
applies	nns	o
:	:	o
is	vbz	o
in	in	o
the	dt	o
set	nn	o
of	in	o
values	nns	o
determined	vbn	o
by	in	o
.	.	o
is	vbz	o
a	dt	o
floating-point	nn	o
type	nn	o
and	cc	o
can	md	o
be	vb	o
rounded	vbn	o
to	to	o
's	pos	o
precision	nn	o
without	in	o
overflow	nn	o
.	.	o
Rounding	vbg	o
uses	nns	o
IEEE	nnp	o
754	cd	o
round-to-even	jj	o
rules	nns	o
but	cc	o
with	in	o
an	dt	o
IEEE	nnp	o
negative	jj	o
zero	nn	o
further	jj	o
simplified	vbd	o
to	to	o
an	dt	o
unsigned	jj	o
zero	cd	o
.	.	o
Note	nn	o
that	wdt	o
constant	nn	o
values	nns	o
never	rb	o
result	nn	o
in	in	o
an	dt	o
IEEE	nnp	o
negative	jj	o
zero	cd	o
,	,	o
NaN	nnp	o
,	,	o
or	cc	o
infinity	nn	o
.	.	o
is	vbz	o
a	dt	o
complex	jj	o
type	nn	o
,	,	o
and	cc	o
's	pos	o
components	nns	o
and	cc	o
are	vbp	o
representable	jj	o
by	in	o
values	nns	o
of	in	o
's	pos	o
component	nn	o
type	nn	o
(	(	o
or	cc	o
)	)	o
.	.	o
If	in	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
with	in	o
specific	jj	o
types	nns	o
,	,	o
is	vbz	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
if	in	o
is	vbz	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
each	dt	o
specific	jj	o
type	nn	o
of	in	o
.	.	o
Method	nnp	b-gpe
sets	vbz	o
The	dt	o
method	nn	o
set	nn	o
of	in	o
a	dt	o
type	nn	o
determines	vbz	o
the	dt	o
methods	nns	o
that	wdt	o
can	md	o
be	vb	o
called	vbd	o
on	in	o
an	dt	o
operand	nn	o
of	in	o
that	wdt	o
type	nn	o
.	.	o
Every	dt	o
type	nn	o
has	vbz	o
a	dt	o
(	(	o
possibly	rb	o
empty	rb	o
)	)	o
method	nn	o
set	nn	o
associated	jj	o
with	in	o
it	prp	o
:	:	o
The	dt	o
method	nn	o
set	nn	o
of	in	o
a	dt	o
defined	vbn	o
type	nn	o
consists	vbz	o
of	in	o
all	pdt	o
methods	nns	o
declared	vbn	o
with	in	o
receiver	nn	o
type	nn	o
.	.	o
The	dt	o
method	nn	o
set	nn	o
of	in	o
a	dt	o
pointer	nn	o
to	to	o
a	dt	o
defined	vbn	o
type	nn	o
(	(	o
where	wrb	o
is	vbz	o
neither	cc	o
a	dt	o
pointer	nn	o
nor	cc	o
an	dt	o
interface	nn	o
)	)	o
is	vbz	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
methods	nns	o
declared	vbn	o
with	in	o
receiver	nn	o
or	cc	o
.	.	o
The	dt	o
method	nn	o
set	nn	o
of	in	o
an	dt	o
interface	nn	o
type	nn	o
is	vbz	o
the	dt	o
intersection	nn	o
of	in	o
the	dt	o
method	nn	o
sets	vbz	o
of	in	o
each	dt	o
type	nn	o
in	in	o
the	dt	o
interface	nn	o
's	pos	o
type	nn	o
set	nn	o
(	(	o
the	dt	o
resulting	vbg	o
method	nn	o
set	nn	o
is	vbz	o
usually	rb	o
just	rb	o
the	dt	o
set	nn	o
of	in	o
declared	vbn	o
methods	nns	o
in	in	o
the	dt	o
interface	nn	o
)	)	o
.	.	o
Further	jj	o
rules	nns	o
apply	vbp	o
to	to	o
structs	nns	o
(	(	o
and	cc	o
pointer	nn	o
to	to	o
structs	nns	o
)	)	o
containing	vbg	o
embedded	jj	o
fields	nns	o
,	,	o
as	in	o
described	vbn	o
in	in	o
the	dt	o
section	nn	o
on	in	o
struct	nn	o
types	nns	o
.	.	o
Any	dt	o
other	jj	o
type	nn	o
has	vbz	o
an	dt	o
empty	jj	o
method	nn	o
set	nn	o
.	.	o
In	in	o
a	dt	o
method	nn	o
set	vbn	o
,	,	o
each	dt	o
method	nn	o
must	md	o
have	vb	o
a	dt	o
unique	jj	o
non-blank	jj	o
method	nn	o
name	nn	o
.	.	o
Blocks	nnp	b-person
A	dt	o
block	nn	o
is	vbz	o
a	dt	o
possibly	rb	o
empty	jj	o
sequence	nn	o
of	in	o
declarations	nns	o
and	cc	o
statements	nns	o
within	in	o
matching	nn	o
brace	nn	o
brackets	nns	o
.	.	o
In	in	o
addition	nn	o
to	to	o
explicit	jj	o
blocks	vbz	o
in	in	o
the	dt	o
source	nn	o
code	nn	o
,	,	o
there	ex	o
are	vbp	o
implicit	jj	o
blocks	nns	o
:	:	o
The	dt	o
universe	jj	o
block	nn	o
encompasses	vbz	o
all	pdt	o
Go	nnp	o
source	nn	o
text	nn	o
.	.	o
Each	dt	o
package	nn	o
has	vbz	o
a	dt	o
package	nn	o
block	nn	o
containing	vbg	o
all	pdt	o
Go	nnp	o
source	nn	o
text	nn	o
for	in	o
that	wdt	o
package	nn	o
.	.	o
Each	dt	o
file	nn	o
has	vbz	o
a	dt	o
file	nn	o
block	nn	o
containing	vbg	o
all	pdt	o
Go	nnp	o
source	nn	o
text	nn	o
in	in	o
that	wdt	o
file	nn	o
.	.	o
Each	dt	o
"	nn	o
if	in	o
"	nnp	o
,	,	o
"	nn	o
for	in	o
"	nn	o
,	,	o
and	cc	o
"	nnp	o
switch	nn	o
"	nnp	o
statement	nn	o
is	vbz	o
considered	vbn	o
to	to	o
be	vb	o
in	in	o
its	prp$	o
own	jj	o
implicit	jj	o
block	nn	o
.	.	o
Each	dt	o
clause	nn	o
in	in	o
a	dt	o
"	nnp	o
switch	nn	o
"	nnp	o
or	cc	o
"	vb	o
select	jj	o
"	nnp	o
statement	nn	o
acts	vbz	o
as	in	o
an	dt	o
implicit	jj	o
block	nn	o
.	.	o
Blocks	nnp	b-person
nest	jjs	o
and	cc	o
influence	nn	o
scoping	nn	o
.	.	o
Declarations	nns	o
and	cc	o
scope	nn	o
A	dt	o
declaration	nn	o
binds	vbz	o
a	dt	o
non-blank	jj	o
identifier	nn	o
to	to	o
a	dt	o
constant	nn	o
,	,	o
type	nn	o
,	,	o
variable	jj	o
,	,	o
function	nn	o
,	,	o
label	nn	o
,	,	o
or	cc	o
package	nn	o
.	.	o
Every	dt	o
identifier	nn	o
in	in	o
a	dt	o
program	nn	o
must	md	o
be	vb	o
declared	vbn	o
.	.	o
No	dt	o
identifier	nn	o
may	md	o
be	vb	o
declared	vbn	o
twice	rb	o
in	in	o
the	dt	o
same	jj	o
block	nn	o
,	,	o
and	cc	o
no	dt	o
identifier	nn	o
may	md	o
be	vb	o
declared	vbn	o
in	in	o
both	dt	o
the	dt	o
file	nn	o
and	cc	o
package	nn	o
block	nn	o
.	.	o
The	dt	o
blank	jj	o
identifier	nn	o
may	md	o
be	vb	o
used	vbn	o
like	in	o
any	dt	o
other	jj	o
identifier	nn	o
in	in	o
a	dt	o
declaration	nn	o
,	,	o
but	cc	o
it	prp	o
does	vbz	o
not	rb	o
introduce	vb	o
a	dt	o
binding	vbg	o
and	cc	o
thus	rb	o
is	vbz	o
not	rb	o
declared	vbn	o
.	.	o
In	in	o
the	dt	o
package	nn	o
block	nn	o
,	,	o
the	dt	o
identifier	nn	o
may	md	o
only	rb	o
be	vb	o
used	vbn	o
for	in	o
function	nn	o
declarations	nns	o
,	,	o
and	cc	o
like	in	o
the	dt	o
blank	jj	o
identifier	nn	o
it	prp	o
does	vbz	o
not	rb	o
introduce	vb	o
a	dt	o
new	jj	o
binding	nn	o
.	.	o
The	dt	o
scope	nn	o
of	in	o
a	dt	o
declared	vbn	o
identifier	nn	o
is	vbz	o
the	dt	o
extent	nn	o
of	in	o
source	nn	o
text	nn	o
in	in	o
which	wdt	o
the	dt	o
identifier	nn	o
denotes	vbz	o
the	dt	o
specified	vbn	o
constant	nn	o
,	,	o
type	nn	o
,	,	o
variable	jj	o
,	,	o
function	nn	o
,	,	o
label	nn	o
,	,	o
or	cc	o
package	nn	o
.	.	o
Go	nnp	o
is	vbz	o
lexically	rb	o
scoped	nns	o
using	vbg	o
blocks	nns	o
:	:	o
The	dt	o
scope	nn	o
of	in	o
a	dt	o
predeclared	jj	o
identifier	nn	o
is	vbz	o
the	dt	o
universe	jj	o
block	nn	o
.	.	o
The	dt	o
scope	nn	o
of	in	o
an	dt	o
identifier	nn	o
denoting	vbg	o
a	dt	o
constant	nn	o
,	,	o
type	nn	o
,	,	o
variable	jj	o
,	,	o
or	cc	o
function	nn	o
(	(	o
but	cc	o
not	rb	o
method	nn	o
)	)	o
declared	vbn	o
at	in	o
top	jj	o
level	nn	o
(	(	o
outside	in	o
any	dt	o
function	nn	o
)	)	o
is	vbz	o
the	dt	o
package	nn	o
block	nn	o
.	.	o
The	dt	o
scope	nn	o
of	in	o
the	dt	o
package	nn	o
name	nn	o
of	in	o
an	dt	o
imported	vbn	o
package	nn	o
is	vbz	o
the	dt	o
file	nn	o
block	nn	o
of	in	o
the	dt	o
file	nn	o
containing	vbg	o
the	dt	o
import	nn	o
declaration	nn	o
.	.	o
The	dt	o
scope	nn	o
of	in	o
an	dt	o
identifier	nn	o
denoting	vbg	o
a	dt	o
method	nn	o
receiver	nn	o
,	,	o
function	nn	o
parameter	nn	o
,	,	o
or	cc	o
result	nn	o
variable	nn	o
is	vbz	o
the	dt	o
function	nn	o
body	nn	o
.	.	o
The	dt	o
scope	nn	o
of	in	o
an	dt	o
identifier	nn	o
denoting	vbg	o
a	dt	o
type	nn	o
parameter	nn	o
of	in	o
a	dt	o
generic	jj	o
function	nn	o
or	cc	o
declared	vbn	o
by	in	o
a	dt	o
method	nn	o
receiver	nn	o
is	vbz	o
the	dt	o
function	nn	o
body	nn	o
and	cc	o
all	pdt	o
parameter	nn	o
lists	nns	o
of	in	o
the	dt	o
function	nn	o
.	.	o
The	dt	o
scope	nn	o
of	in	o
an	dt	o
identifier	nn	o
denoting	vbg	o
a	dt	o
type	nn	o
parameter	nn	o
of	in	o
a	dt	o
generic	jj	o
type	nn	o
begins	vbz	o
after	in	o
the	dt	o
name	nn	o
of	in	o
the	dt	o
generic	jj	o
type	nn	o
and	cc	o
ends	vbz	o
at	in	o
the	dt	o
end	nn	o
of	in	o
the	dt	o
TypeSpec	nnp	b-gpe
.	.	o
The	dt	o
scope	nn	o
of	in	o
a	dt	o
constant	nn	o
or	cc	o
variable	nn	o
identifier	nn	o
declared	vbn	o
inside	in	o
a	dt	o
function	nn	o
begins	vbz	o
at	in	o
the	dt	o
end	nn	o
of	in	o
the	dt	o
ConstSpec	nnp	o
or	cc	o
VarSpec	nnp	b-gpe
(	(	o
ShortVarDecl	nnp	o
for	in	o
short	jj	o
variable	nn	o
declarations	nns	o
)	)	o
and	cc	o
ends	vbz	o
at	in	o
the	dt	o
end	nn	o
of	in	o
the	dt	o
innermost	nn	o
containing	vbg	o
block	nn	o
.	.	o
The	dt	o
scope	nn	o
of	in	o
a	dt	o
type	nn	o
identifier	nn	o
declared	vbn	o
inside	in	o
a	dt	o
function	nn	o
begins	vbz	o
at	in	o
the	dt	o
identifier	nn	o
in	in	o
the	dt	o
TypeSpec	nnp	b-gpe
and	cc	o
ends	vbz	o
at	in	o
the	dt	o
end	nn	o
of	in	o
the	dt	o
innermost	nn	o
containing	vbg	o
block	nn	o
.	.	o
An	dt	o
identifier	nn	o
declared	vbn	o
in	in	o
a	dt	o
block	nn	o
may	md	o
be	vb	o
redeclared	vbn	o
in	in	o
an	dt	o
inner	jj	o
block	nn	o
.	.	o
While	in	o
the	dt	o
identifier	nn	o
of	in	o
the	dt	o
inner	jj	o
declaration	nn	o
is	vbz	o
in	in	o
scope	nn	o
,	,	o
it	prp	o
denotes	vbz	o
the	dt	o
entity	nn	o
declared	vbn	o
by	in	o
the	dt	o
inner	jj	o
declaration	nn	o
.	.	o
The	dt	o
package	nn	o
clause	nn	o
is	vbz	o
not	rb	o
a	dt	o
declaration	nn	o
;	:	o
the	dt	o
package	nn	o
name	nn	o
does	vbz	o
not	rb	o
appear	vbp	o
in	in	o
any	dt	o
scope	nn	o
.	.	o
Its	prp$	o
purpose	nn	o
is	vbz	o
to	to	o
identify	vb	o
the	dt	o
files	nns	o
belonging	vbg	o
to	to	o
the	dt	o
same	jj	o
package	nn	o
and	cc	o
to	to	o
specify	vb	o
the	dt	o
default	nn	o
package	nn	o
name	nn	o
for	in	o
import	nn	o
declarations	nns	o
.	.	o
Label	nnp	b-person
scopes	vbz	o
Labels	nnp	b-gpe
are	vbp	o
declared	vbn	o
by	in	o
labeled	jj	o
statements	nns	o
and	cc	o
are	vbp	o
used	vbn	o
in	in	o
the	dt	o
"	nnp	o
break	nn	o
"	nn	o
,	,	o
"	nnp	o
continue	vbp	o
"	nnp	o
,	,	o
and	cc	o
"	jj	o
goto	nn	o
"	nnp	o
statements	nns	o
.	.	o
It	prp	o
is	vbz	o
illegal	jj	o
to	to	o
define	vb	o
a	dt	o
label	nn	o
that	wdt	o
is	vbz	o
never	rb	o
used	vbn	o
.	.	o
In	in	o
contrast	nn	o
to	to	o
other	jj	o
identifiers	nns	o
,	,	o
labels	nns	o
are	vbp	o
not	rb	o
block	nn	o
scoped	nns	o
and	cc	o
do	vbp	o
not	rb	o
conflict	vb	o
with	in	o
identifiers	nns	o
that	wdt	o
are	vbp	o
not	rb	o
labels	nns	o
.	.	o
The	dt	o
scope	nn	o
of	in	o
a	dt	o
label	nn	o
is	vbz	o
the	dt	o
body	nn	o
of	in	o
the	dt	o
function	nn	o
in	in	o
which	wdt	o
it	prp	o
is	vbz	o
declared	vbn	o
and	cc	o
excludes	vbz	o
the	dt	o
body	nn	o
of	in	o
any	dt	o
nested	jj	o
function	nn	o
.	.	o
Blank	nnp	b-person
identifier	nn	o
The	dt	o
blank	jj	o
identifier	nn	o
is	vbz	o
represented	vbn	o
by	in	o
the	dt	o
underscore	jj	o
character	nn	o
.	.	o
It	prp	o
serves	vbz	o
as	in	o
an	dt	o
anonymous	jj	o
placeholder	nn	o
instead	rb	o
of	in	o
a	dt	o
regular	jj	o
(	(	o
non-blank	jj	o
)	)	o
identifier	nn	o
and	cc	o
has	vbz	o
special	jj	o
meaning	nn	o
in	in	o
declarations	nns	o
,	,	o
as	in	o
an	dt	o
operand	nn	o
,	,	o
and	cc	o
in	in	o
assignments	nns	o
.	.	o
Predeclared	vbd	o
identifiers	nns	o
The	dt	o
following	vbg	o
identifiers	nns	o
are	vbp	o
implicitly	rb	o
declared	vbn	o
in	in	o
the	dt	o
universe	jj	o
block	nn	o
:	:	o
Types	nns	o
:	:	o
any	dt	o
bool	nn	o
byte	nn	o
comparable	jj	o
complex64	jj	o
complex128	nn	o
error	nn	o
float32	vbp	o
float64	nn	o
int	nn	o
int8	jj	o
int16	jj	o
int32	nn	o
int64	nn	o
rune	nns	o
string	vbg	o
uint	jj	o
uint8	jj	o
uint16	jj	o
uint32	jj	o
uint64	jj	o
uintptr	vbp	o
Constants	nns	o
:	:	o
true	jj	o
false	jj	o
iota	nn	o
Zero	nnp	o
value	nn	o
:	:	o
nil	jj	o
Functions	nns	o
:	:	o
append	vb	o
cap	nn	o
close	rb	o
complex	jj	o
copy	nn	o
delete	nn	o
imag	nn	o
len	nnp	o
make	vbp	o
new	jj	o
panic	nn	o
print	nn	o
println	nns	o
real	jj	o
recover	nn	o
Exported	vbd	o
identifiers	nns	o
An	dt	o
identifier	nn	o
may	md	o
be	vb	o
exported	jj	o
to	to	o
permit	vb	o
access	nn	o
to	to	o
it	prp	o
from	in	o
another	dt	o
package	nn	o
.	.	o
An	dt	o
identifier	nn	o
is	vbz	o
exported	jj	o
if	in	o
both	dt	o
:	:	o
the	dt	o
first	jj	o
character	nn	o
of	in	o
the	dt	o
identifier	nn	o
's	pos	o
name	nn	o
is	vbz	o
a	dt	o
Unicode	nnp	b-gpe
upper	jj	o
case	nn	o
letter	nn	o
(	(	o
Unicode	nnp	b-gpe
class	nn	o
"	nnp	o
Lu	nnp	o
"	nnp	o
)	)	o
;	:	o
and	cc	o
the	dt	o
identifier	nn	o
is	vbz	o
declared	vbn	o
in	in	o
the	dt	o
package	nn	o
block	nn	o
or	cc	o
it	prp	o
is	vbz	o
a	dt	o
field	nn	o
name	nn	o
or	cc	o
method	nn	o
name	nn	o
.	.	o
All	dt	o
other	jj	o
identifiers	nns	o
are	vbp	o
not	rb	o
exported	vbn	o
.	.	o
Uniqueness	nnp	o
of	in	o
identifiers	nns	o
Given	vbn	o
a	dt	o
set	nn	o
of	in	o
identifiers	nns	o
,	,	o
an	dt	o
identifier	nn	o
is	vbz	o
called	vbd	o
unique	jj	o
if	in	o
it	prp	o
is	vbz	o
different	jj	o
from	in	o
every	dt	o
other	jj	o
in	in	o
the	dt	o
set	nn	o
.	.	o
Two	cd	o
identifiers	nns	o
are	vbp	o
different	jj	o
if	in	o
they	prp	o
are	vbp	o
spelled	vbn	o
differently	rb	o
,	,	o
or	cc	o
if	in	o
they	prp	o
appear	vbp	o
in	in	o
different	jj	o
packages	nns	o
and	cc	o
are	vbp	o
not	rb	o
exported	vbn	o
.	.	o
Otherwise	rb	o
,	,	o
they	prp	o
are	vbp	o
the	dt	o
same	jj	o
.	.	o
Constant	jj	o
declarations	nns	o
A	dt	o
constant	nn	o
declaration	nn	o
binds	vbz	o
a	dt	o
list	nn	o
of	in	o
identifiers	nns	o
(	(	o
the	dt	o
names	vbz	o
of	in	o
the	dt	o
constants	nns	o
)	)	o
to	to	o
the	dt	o
values	nns	o
of	in	o
a	dt	o
list	nn	o
of	in	o
constant	nn	o
expressions	nns	o
.	.	o
The	dt	o
number	nn	o
of	in	o
identifiers	nns	o
must	md	o
be	vb	o
equal	vb	o
to	to	o
the	dt	o
number	nn	o
of	in	o
expressions	nns	o
,	,	o
and	cc	o
the	dt	o
nth	jj	o
identifier	nn	o
on	in	o
the	dt	o
left	nn	o
is	vbz	o
bound	vbn	o
to	to	o
the	dt	o
value	nn	o
of	in	o
the	dt	o
nth	jj	o
expression	nn	o
on	in	o
the	dt	o
right	vb	o
.	.	o
If	in	o
the	dt	o
type	nn	o
is	vbz	o
present	jj	o
,	,	o
all	pdt	o
constants	nns	o
take	vb	o
the	dt	o
type	nn	o
specified	vbn	o
,	,	o
and	cc	o
the	dt	o
expressions	nns	o
must	md	o
be	vb	o
assignable	jj	o
to	to	o
that	wdt	o
type	nn	o
,	,	o
which	wdt	o
must	md	o
not	rb	o
be	vb	o
a	dt	o
type	nn	o
parameter	nn	o
.	.	o
If	in	o
the	dt	o
type	nn	o
is	vbz	o
omitted	vbn	o
,	,	o
the	dt	o
constants	nns	o
take	vb	o
the	dt	o
individual	jj	o
types	nns	o
of	in	o
the	dt	o
corresponding	jj	o
expressions	nns	o
.	.	o
If	in	o
the	dt	o
expression	nn	o
values	nns	o
are	vbp	o
untyped	jj	o
constants	nns	o
,	,	o
the	dt	o
declared	vbn	o
constants	nns	o
remain	vbp	o
untyped	jj	o
and	cc	o
the	dt	o
constant	nn	o
identifiers	nns	o
denote	vbp	o
the	dt	o
constant	nn	o
values	nns	o
.	.	o
For	in	o
instance	nn	o
,	,	o
if	in	o
the	dt	o
expression	nn	o
is	vbz	o
a	dt	o
floating-point	nn	o
literal	jj	o
,	,	o
the	dt	o
constant	nn	o
identifier	nn	o
denotes	vbz	o
a	dt	o
floating-point	nn	o
constant	nn	o
,	,	o
even	rb	o
if	in	o
the	dt	o
literal	nn	o
's	pos	o
fractional	jj	o
part	nn	o
is	vbz	o
zero	cd	o
.	.	o
Within	in	o
a	dt	o
parenthesized	vbn	o
declaration	nn	o
list	nn	o
the	dt	o
expression	nn	o
list	nn	o
may	md	o
be	vb	o
omitted	vbn	o
from	in	o
any	dt	o
but	cc	o
the	dt	o
first	jj	o
ConstSpec	nnp	o
.	.	o
Such	jj	o
an	dt	o
empty	jj	o
list	nn	o
is	vbz	o
equivalent	jj	o
to	to	o
the	dt	o
textual	jj	o
substitution	nn	o
of	in	o
the	dt	o
first	jj	o
preceding	vbg	o
non-empty	jj	o
expression	nn	o
list	nn	o
and	cc	o
its	prp$	o
type	nn	o
if	in	o
any	dt	o
.	.	o
Omitting	vbg	o
the	dt	o
list	nn	o
of	in	o
expressions	nns	o
is	vbz	o
therefore	rb	o
equivalent	jj	o
to	to	o
repeating	vbg	o
the	dt	o
previous	jj	o
list	nn	o
.	.	o
The	dt	o
number	nn	o
of	in	o
identifiers	nns	o
must	md	o
be	vb	o
equal	vb	o
to	to	o
the	dt	o
number	nn	o
of	in	o
expressions	nns	o
in	in	o
the	dt	o
previous	jj	o
list	nn	o
.	.	o
Together	rb	o
with	in	o
the	dt	o
constant	nn	o
generator	nn	o
this	dt	o
mechanism	nn	o
permits	vbz	o
light-weight	jj	o
declaration	nn	o
of	in	o
sequential	jj	o
values	nns	o
:	:	o
Iota	nnp	o
Within	in	o
a	dt	o
constant	nn	o
declaration	nn	o
,	,	o
the	dt	o
predeclared	jj	o
identifier	nn	o
represents	vbz	o
successive	jj	o
untyped	jj	o
integer	jj	o
constants	nns	o
.	.	o
Its	prp$	o
value	nn	o
is	vbz	o
the	dt	o
index	nn	o
of	in	o
the	dt	o
respective	jj	o
ConstSpec	nnp	o
in	in	o
that	wdt	o
constant	nn	o
declaration	nn	o
,	,	o
starting	vbg	o
at	in	o
zero	cd	o
.	.	o
It	prp	o
can	md	o
be	vb	o
used	vbn	o
to	to	o
construct	nn	o
a	dt	o
set	nn	o
of	in	o
related	jj	o
constants	nns	o
:	:	o
By	in	o
definition	nn	o
,	,	o
multiple	nn	o
uses	nns	o
of	in	o
in	in	o
the	dt	o
same	jj	o
ConstSpec	nnp	o
all	pdt	o
have	vb	o
the	dt	o
same	jj	o
value	nn	o
:	:	o
This	dt	o
last	jj	o
example	nn	o
exploits	vbz	o
the	dt	o
implicit	jj	o
repetition	nn	o
of	in	o
the	dt	o
last	jj	o
non-empty	jj	o
expression	nn	o
list	nn	o
.	.	o
Type	nnp	b-person
declarations	nns	o
A	dt	o
type	nn	o
declaration	nn	o
binds	vbz	o
an	dt	o
identifier	nn	o
,	,	o
the	dt	o
type	nn	o
name	nn	o
,	,	o
to	to	o
a	dt	o
type	nn	o
.	.	o
Type	nnp	b-person
declarations	nns	o
come	vb	o
in	in	o
two	cd	o
forms	nns	o
:	:	o
alias	nn	o
declarations	nns	o
and	cc	o
type	nn	o
definitions	nns	o
.	.	o
Alias	nnp	o
declarations	nns	o
An	dt	o
alias	nn	o
declaration	nn	o
binds	vbz	o
an	dt	o
identifier	nn	o
to	to	o
the	dt	o
given	vbn	o
type	nn	o
.	.	o
Within	in	o
the	dt	o
scope	nn	o
of	in	o
the	dt	o
identifier	nn	o
,	,	o
it	prp	o
serves	vbz	o
as	in	o
an	dt	o
alias	nn	o
for	in	o
the	dt	o
type	nn	o
.	.	o
Type	nnp	b-person
definitions	nns	o
A	dt	o
type	nn	o
definition	nn	o
creates	vbz	o
a	dt	o
new	jj	o
,	,	o
distinct	jj	o
type	nn	o
with	in	o
the	dt	o
same	jj	o
underlying	jj	o
type	nn	o
and	cc	o
operations	nns	o
as	in	o
the	dt	o
given	vbn	o
type	nn	o
and	cc	o
binds	vbz	o
an	dt	o
identifier	nn	o
,	,	o
the	dt	o
type	nn	o
name	nn	o
,	,	o
to	to	o
it	prp	o
.	.	o
The	dt	o
new	jj	o
type	nn	o
is	vbz	o
called	vbd	o
a	dt	o
defined	vbn	o
type	nn	o
.	.	o
It	prp	o
is	vbz	o
different	jj	o
from	in	o
any	dt	o
other	jj	o
type	nn	o
,	,	o
including	vbg	o
the	dt	o
type	nn	o
it	prp	o
is	vbz	o
created	vbn	o
from	in	o
.	.	o
A	dt	o
defined	vbn	o
type	nn	o
may	md	o
have	vb	o
methods	nns	o
associated	jj	o
with	in	o
it	prp	o
.	.	o
It	prp	o
does	vbz	o
not	rb	o
inherit	vb	o
any	dt	o
methods	nns	o
bound	vbn	o
to	to	o
the	dt	o
given	vbn	o
type	nn	o
,	,	o
but	cc	o
the	dt	o
method	nn	o
set	nn	o
of	in	o
an	dt	o
interface	nn	o
type	nn	o
or	cc	o
of	in	o
elements	nns	o
of	in	o
a	dt	o
composite	jj	o
type	nn	o
remains	vbz	o
unchanged	jj	o
:	:	o
Type	nnp	b-person
definitions	nns	o
may	md	o
be	vb	o
used	vbn	o
to	to	o
define	vb	o
different	jj	o
boolean	nn	o
,	,	o
numeric	jj	o
,	,	o
or	cc	o
string	vbg	o
types	nns	o
and	cc	o
associate	nn	o
methods	nns	o
with	in	o
them	prp	o
:	:	o
If	in	o
the	dt	o
type	nn	o
definition	nn	o
specifies	vbz	o
type	nn	o
parameters	nns	o
,	,	o
the	dt	o
type	nn	o
name	nn	o
denotes	vbz	o
a	dt	o
generic	jj	o
type	nn	o
.	.	o
Generic	nnp	o
types	nns	o
must	md	o
be	vb	o
instantiated	vbn	o
when	wrb	o
they	prp	o
are	vbp	o
used	vbn	o
.	.	o
The	dt	o
given	vbn	o
type	nn	o
cannot	vbp	o
be	vb	o
a	dt	o
type	nn	o
parameter	nn	o
in	in	o
a	dt	o
type	nn	o
definition	nn	o
.	.	o
A	dt	o
generic	jj	o
type	nn	o
may	md	o
also	rb	o
have	vb	o
methods	nns	o
associated	jj	o
with	in	o
it	prp	o
.	.	o
In	in	o
this	dt	o
case	nn	o
,	,	o
the	dt	o
method	nn	o
receivers	nns	o
must	md	o
declare	vb	o
the	dt	o
same	jj	o
number	nn	o
of	in	o
type	nn	o
parameters	nns	o
as	in	o
present	vb	o
in	in	o
the	dt	o
generic	jj	o
type	nn	o
definition	nn	o
.	.	o
Type	nnp	b-person
parameter	nn	o
lists	nns	o
A	dt	o
type	nn	o
parameter	nn	o
list	nn	o
declares	vbz	o
the	dt	o
type	nn	o
parameters	nns	o
of	in	o
a	dt	o
generic	jj	o
function	nn	o
or	cc	o
type	nn	o
declaration	nn	o
.	.	o
The	dt	o
type	nn	o
parameter	nn	o
list	nn	o
looks	vbz	o
like	in	o
an	dt	o
ordinary	jj	o
function	nn	o
parameter	nn	o
list	nn	o
except	vb	o
that	wdt	o
the	dt	o
type	nn	o
parameter	nn	o
names	vbz	o
must	md	o
all	pdt	o
be	vb	o
present	vb	o
and	cc	o
the	dt	o
list	nn	o
is	vbz	o
enclosed	vbn	o
in	in	o
square	jj	o
brackets	nns	o
rather	rb	o
than	in	o
parentheses	nns	o
.	.	o
All	dt	o
non-blank	jj	o
names	vbz	o
in	in	o
the	dt	o
list	nn	o
must	md	o
be	vb	o
unique	jj	o
.	.	o
Each	dt	o
name	nn	o
declares	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
which	wdt	o
is	vbz	o
a	dt	o
new	jj	o
and	cc	o
different	jj	o
named	vbn	o
type	nn	o
that	wdt	o
acts	vbz	o
as	in	o
a	dt	o
place	nn	o
holder	nn	o
for	in	o
an	dt	o
(	(	o
as	in	o
of	in	o
yet	rb	o
)	)	o
unknown	jj	o
type	nn	o
in	in	o
the	dt	o
declaration	nn	o
.	.	o
The	dt	o
type	nn	o
parameter	nn	o
is	vbz	o
replaced	vbn	o
with	in	o
a	dt	o
type	nn	o
argument	nn	o
upon	in	o
instantiation	nn	o
of	in	o
the	dt	o
generic	jj	o
function	nn	o
or	cc	o
type	nn	o
.	.	o
Just	rb	o
as	in	o
each	dt	o
ordinary	jj	o
function	nn	o
parameter	nn	o
has	vbz	o
a	dt	o
parameter	nn	o
type	nn	o
,	,	o
each	dt	o
type	nn	o
parameter	nn	o
has	vbz	o
a	dt	o
corresponding	jj	o
(	(	o
meta-)type	jj	o
which	wdt	o
is	vbz	o
called	vbd	o
its	prp$	o
type	nn	o
constraint	nn	o
.	.	o
A	dt	o
parsing	jj	o
ambiguity	nn	o
arises	nns	o
when	wrb	o
the	dt	o
type	nn	o
parameter	nn	o
list	nn	o
for	in	o
a	dt	o
generic	jj	o
type	nn	o
declares	vbz	o
a	dt	o
single	jj	o
type	nn	o
parameter	nn	o
with	in	o
a	dt	o
type	nn	o
constraint	nn	o
of	in	o
the	dt	o
form	nn	o
or	cc	o
where	wrb	o
is	vbz	o
not	rb	o
a	dt	o
(	(	o
possibly	rb	o
parenthesized	vbn	o
)	)	o
type	nn	o
literal	jj	o
:	:	o
In	in	o
these	dt	o
rare	jj	o
cases	nns	o
,	,	o
the	dt	o
type	nn	o
parameter	nn	o
declaration	nn	o
is	vbz	o
indistinguishable	jj	o
from	in	o
the	dt	o
expressions	nns	o
or	cc	o
and	cc	o
the	dt	o
type	nn	o
declaration	nn	o
is	vbz	o
parsed	vbn	o
as	in	o
an	dt	o
array	nn	o
type	nn	o
declaration	nn	o
.	.	o
To	to	o
resolve	vb	o
the	dt	o
ambiguity	nn	o
,	,	o
embed	nn	o
the	dt	o
constraint	nn	o
in	in	o
an	dt	o
interface	nn	o
or	cc	o
use	vbp	o
a	dt	o
trailing	nn	o
comma	nn	o
:	:	o
Type	nnp	b-person
parameters	nns	o
may	md	o
also	rb	o
be	vb	o
declared	vbn	o
by	in	o
the	dt	o
receiver	nn	o
specification	nn	o
of	in	o
a	dt	o
method	nn	o
declaration	nn	o
associated	jj	o
with	in	o
a	dt	o
generic	jj	o
type	nn	o
.	.	o
Type	nnp	b-person
constraints	nns	o
A	dt	o
type	nn	o
constraint	nn	o
is	vbz	o
an	dt	o
interface	nn	o
that	wdt	o
defines	vbz	o
the	dt	o
set	nn	o
of	in	o
permissible	jj	o
type	nn	o
arguments	nns	o
for	in	o
the	dt	o
respective	jj	o
type	nn	o
parameter	nn	o
and	cc	o
controls	vbz	o
the	dt	o
operations	nns	o
supported	vbn	o
by	in	o
values	nns	o
of	in	o
that	wdt	o
type	nn	o
parameter	nn	o
.	.	o
If	in	o
the	dt	o
constraint	nn	o
is	vbz	o
an	dt	o
interface	nn	o
literal	nn	o
of	in	o
the	dt	o
form	nn	o
where	wrb	o
is	vbz	o
an	dt	o
embedded	jj	o
type	nn	o
element	nn	o
(	(	o
not	rb	o
a	dt	o
method	nn	o
)	)	o
,	,	o
in	in	o
a	dt	o
type	nn	o
parameter	nn	o
list	nn	o
the	dt	o
enclosing	vbg	o
may	md	o
be	vb	o
omitted	vbn	o
for	in	o
convenience	nn	o
:	:	o
The	dt	o
predeclared	jj	o
interface	nn	o
type	nn	o
denotes	vbz	o
the	dt	o
set	nn	o
of	in	o
all	pdt	o
concrete	jj	o
(	(	o
non-interface	nn	o
)	)	o
types	nns	o
that	wdt	o
are	vbp	o
comparable	jj	o
.	.	o
Specifically	rb	o
,	,	o
a	dt	o
type	nn	o
implements	vbz	o
if	in	o
:	:	o
is	vbz	o
not	rb	o
an	dt	o
interface	nn	o
type	nn	o
and	cc	o
supports	vbz	o
the	dt	o
operations	nns	o
and	cc	o
;	:	o
or	cc	o
is	vbz	o
an	dt	o
interface	nn	o
type	nn	o
and	cc	o
each	dt	o
type	nn	o
in	in	o
's	pos	o
type	nn	o
set	nn	o
implements	vbz	o
.	.	o
Even	rb	o
though	in	o
interfaces	nns	o
that	wdt	o
are	vbp	o
not	rb	o
type	nn	o
parameters	nns	o
can	md	o
be	vb	o
compared	vbn	o
(	(	o
possibly	rb	o
causing	vbg	o
a	dt	o
run-time	jj	o
panic	nn	o
)	)	o
they	prp	o
do	vbp	o
not	rb	o
implement	vb	o
.	.	o
The	dt	o
interface	nn	o
and	cc	o
interfaces	nns	o
that	wdt	o
(	(	o
directly	rb	o
or	cc	o
indirectly	rb	o
)	)	o
embed	nn	o
may	md	o
only	rb	o
be	vb	o
used	vbn	o
as	in	o
type	nn	o
constraints	nns	o
.	.	o
They	prp	o
cannot	vbp	o
be	vb	o
the	dt	o
types	nns	o
of	in	o
values	nns	o
or	cc	o
variables	nns	o
,	,	o
or	cc	o
components	nns	o
of	in	o
other	jj	o
,	,	o
non-interface	jj	o
types	nns	o
.	.	o
Variable	jj	o
declarations	nns	o
A	dt	o
variable	nn	o
declaration	nn	o
creates	vbz	o
one	nn	o
or	cc	o
more	jjr	o
variables	nns	o
,	,	o
binds	vbz	o
corresponding	jj	o
identifiers	nns	o
to	to	o
them	prp	o
,	,	o
and	cc	o
gives	vbz	o
each	dt	o
a	dt	o
type	nn	o
and	cc	o
an	dt	o
initial	jj	o
value	nn	o
.	.	o
If	in	o
a	dt	o
list	nn	o
of	in	o
expressions	nns	o
is	vbz	o
given	vbn	o
,	,	o
the	dt	o
variables	nns	o
are	vbp	o
initialized	vbn	o
with	in	o
the	dt	o
expressions	nns	o
following	vbg	o
the	dt	o
rules	nns	o
for	in	o
assignments	nns	o
.	.	o
Otherwise	rb	o
,	,	o
each	dt	o
variable	nn	o
is	vbz	o
initialized	vbn	o
to	to	o
its	prp$	o
zero	nn	o
value	nn	o
.	.	o
If	in	o
a	dt	o
type	nn	o
is	vbz	o
present	jj	o
,	,	o
each	dt	o
variable	nn	o
is	vbz	o
given	vbn	o
that	wdt	o
type	nn	o
.	.	o
Otherwise	rb	o
,	,	o
each	dt	o
variable	nn	o
is	vbz	o
given	vbn	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
corresponding	jj	o
initialization	nn	o
value	nn	o
in	in	o
the	dt	o
assignment	nn	o
.	.	o
If	in	o
that	wdt	o
value	nn	o
is	vbz	o
an	dt	o
untyped	jj	o
constant	nn	o
,	,	o
it	prp	o
is	vbz	o
first	jj	o
implicitly	rb	o
converted	vbn	o
to	to	o
its	prp$	o
default	nn	o
type	nn	o
;	:	o
if	in	o
it	prp	o
is	vbz	o
an	dt	o
untyped	jj	o
boolean	jj	o
value	nn	o
,	,	o
it	prp	o
is	vbz	o
first	jj	o
implicitly	rb	o
converted	vbn	o
to	to	o
type	nn	o
.	.	o
The	dt	o
predeclared	jj	o
value	nn	o
cannot	vbp	o
be	vb	o
used	vbn	o
to	to	o
initialize	vb	o
a	dt	o
variable	nn	o
with	in	o
no	dt	o
explicit	jj	o
type	nn	o
.	.	o
Implementation	nnp	o
restriction	nn	o
:	:	o
A	dt	o
compiler	nn	o
may	md	o
make	vbp	o
it	prp	o
illegal	jj	o
to	to	o
declare	vb	o
a	dt	o
variable	nn	o
inside	in	o
a	dt	o
function	nn	o
body	nn	o
if	in	o
the	dt	o
variable	nn	o
is	vbz	o
never	rb	o
used	vbn	o
.	.	o
Short	nnp	o
variable	nn	o
declarations	nns	o
A	dt	o
short	jj	o
variable	nn	o
declaration	nn	o
uses	nns	o
the	dt	o
syntax	nn	o
:	:	o
It	prp	o
is	vbz	o
shorthand	nn	o
for	in	o
a	dt	o
regular	jj	o
variable	nn	o
declaration	nn	o
with	in	o
initializer	jj	o
expressions	nns	o
but	cc	o
no	dt	o
types	nns	o
:	:	o
"	nn	o
var	nn	o
"	nnp	o
IdentifierList	nnp	o
=	nnp	o
ExpressionList	nnp	o
.	.	o
Unlike	in	o
regular	jj	o
variable	nn	o
declarations	nns	o
,	,	o
a	dt	o
short	jj	o
variable	nn	o
declaration	nn	o
may	md	o
redeclare	vb	o
variables	nns	o
provided	vbn	o
they	prp	o
were	vbd	o
originally	rb	o
declared	vbn	o
earlier	rbr	o
in	in	o
the	dt	o
same	jj	o
block	nn	o
(	(	o
or	cc	o
the	dt	o
parameter	nn	o
lists	nns	o
if	in	o
the	dt	o
block	nn	o
is	vbz	o
the	dt	o
function	nn	o
body	nn	o
)	)	o
with	in	o
the	dt	o
same	jj	o
type	nn	o
,	,	o
and	cc	o
at	in	o
least	jjs	o
one	nn	o
of	in	o
the	dt	o
non-blank	jj	o
variables	nns	o
is	vbz	o
new	jj	o
.	.	o
As	in	o
a	dt	o
consequence	nn	o
,	,	o
redeclaration	nn	o
can	md	o
only	rb	o
appear	vbp	o
in	in	o
a	dt	o
multi-variable	jj	o
short	jj	o
declaration	nn	o
.	.	o
Redeclaration	nn	o
does	vbz	o
not	rb	o
introduce	vb	o
a	dt	o
new	jj	o
variable	nn	o
;	:	o
it	prp	o
just	rb	o
assigns	vbz	o
a	dt	o
new	jj	o
value	nn	o
to	to	o
the	dt	o
original	jj	o
.	.	o
Short	nnp	o
variable	nn	o
declarations	nns	o
may	md	o
appear	vbp	o
only	rb	o
inside	in	o
functions	nns	o
.	.	o
In	in	o
some	dt	o
contexts	nns	o
such	jj	o
as	in	o
the	dt	o
initializers	nns	o
for	in	o
"	nn	o
if	in	o
"	nnp	o
,	,	o
"	nn	o
for	in	o
"	nn	o
,	,	o
or	cc	o
"	nnp	o
switch	nn	o
"	nnp	o
statements	nns	o
,	,	o
they	prp	o
can	md	o
be	vb	o
used	vbn	o
to	to	o
declare	vb	o
local	jj	o
temporary	jj	o
variables	nns	o
.	.	o
Function	nnp	b-person
declarations	nns	o
A	dt	o
function	nn	o
declaration	nn	o
binds	vbz	o
an	dt	o
identifier	nn	o
,	,	o
the	dt	o
function	nn	o
name	nn	o
,	,	o
to	to	o
a	dt	o
function	nn	o
.	.	o
If	in	o
the	dt	o
function	nn	o
's	pos	o
signature	nn	o
declares	vbz	o
result	nn	o
parameters	nns	o
,	,	o
the	dt	o
function	nn	o
body	nn	o
's	pos	o
statement	nn	o
list	nn	o
must	md	o
end	nn	o
in	in	o
a	dt	o
terminating	nn	o
statement	nn	o
.	.	o
If	in	o
the	dt	o
function	nn	o
declaration	nn	o
specifies	vbz	o
type	nn	o
parameters	nns	o
,	,	o
the	dt	o
function	nn	o
name	nn	o
denotes	vbz	o
a	dt	o
generic	jj	o
function	nn	o
.	.	o
Generic	nnp	o
functions	nns	o
must	md	o
be	vb	o
instantiated	vbn	o
when	wrb	o
they	prp	o
are	vbp	o
used	vbn	o
.	.	o
A	dt	o
function	nn	o
declaration	nn	o
without	in	o
type	nn	o
parameters	nns	o
may	md	o
omit	vb	o
the	dt	o
body	nn	o
.	.	o
Such	jj	o
a	dt	o
declaration	nn	o
provides	vbz	o
the	dt	o
signature	nn	o
for	in	o
a	dt	o
function	nn	o
implemented	vbd	o
outside	in	o
Go	nnp	b-gpe
,	,	o
such	jj	o
as	in	o
an	dt	o
assembly	nn	o
routine	nn	o
.	.	o
Method	nnp	b-gpe
declarations	nns	o
A	dt	o
method	nn	o
is	vbz	o
a	dt	o
function	nn	o
with	in	o
a	dt	o
receiver	nn	o
.	.	o
A	dt	o
method	nn	o
declaration	nn	o
binds	vbz	o
an	dt	o
identifier	nn	o
,	,	o
the	dt	o
method	nn	o
name	nn	o
,	,	o
to	to	o
a	dt	o
method	nn	o
,	,	o
and	cc	o
associates	vbz	o
the	dt	o
method	nn	o
with	in	o
the	dt	o
receiver	nn	o
's	pos	o
base	nn	o
type	nn	o
.	.	o
The	dt	o
receiver	nn	o
is	vbz	o
specified	vbn	o
via	in	o
an	dt	o
extra	jj	o
parameter	nn	o
section	nn	o
preceding	vbg	o
the	dt	o
method	nn	o
name	nn	o
.	.	o
That	dt	o
parameter	nn	o
section	nn	o
must	md	o
declare	vb	o
a	dt	o
single	jj	o
non-variadic	jj	o
parameter	nn	o
,	,	o
the	dt	o
receiver	nn	o
.	.	o
Its	prp$	o
type	nn	o
must	md	o
be	vb	o
a	dt	o
defined	vbn	o
type	nn	o
or	cc	o
a	dt	o
pointer	nn	o
to	to	o
a	dt	o
defined	vbn	o
type	nn	o
,	,	o
possibly	rb	o
followed	vbn	o
by	in	o
a	dt	o
list	nn	o
of	in	o
type	nn	o
parameter	nn	o
names	vbz	o
enclosed	vbn	o
in	in	o
square	jj	o
brackets	nns	o
.	.	o
is	vbz	o
called	vbd	o
the	dt	o
receiver	nn	o
base	nn	o
type	nn	o
.	.	o
A	dt	o
receiver	nn	o
base	nn	o
type	nn	o
cannot	vbp	o
be	vb	o
a	dt	o
pointer	nn	o
or	cc	o
interface	nn	o
type	nn	o
and	cc	o
it	prp	o
must	md	o
be	vb	o
defined	vbn	o
in	in	o
the	dt	o
same	jj	o
package	nn	o
as	in	o
the	dt	o
method	nn	o
.	.	o
The	dt	o
method	nn	o
is	vbz	o
said	vbd	o
to	to	o
be	vb	o
bound	vbn	o
to	to	o
its	prp$	o
receiver	nn	o
base	nn	o
type	nn	o
and	cc	o
the	dt	o
method	nn	o
name	nn	o
is	vbz	o
visible	jj	o
only	rb	o
within	in	o
selectors	nns	o
for	in	o
type	nn	o
or	cc	o
.	.	o
A	dt	o
non-blank	jj	o
receiver	nn	o
identifier	nn	o
must	md	o
be	vb	o
unique	jj	o
in	in	o
the	dt	o
method	nn	o
signature	nn	o
.	.	o
If	in	o
the	dt	o
receiver	nn	o
's	pos	o
value	nn	o
is	vbz	o
not	rb	o
referenced	vbn	o
inside	in	o
the	dt	o
body	nn	o
of	in	o
the	dt	o
method	nn	o
,	,	o
its	prp$	o
identifier	nn	o
may	md	o
be	vb	o
omitted	vbn	o
in	in	o
the	dt	o
declaration	nn	o
.	.	o
The	dt	o
same	jj	o
applies	nns	o
in	in	o
general	jj	o
to	to	o
parameters	nns	o
of	in	o
functions	nns	o
and	cc	o
methods	nns	o
.	.	o
For	in	o
a	dt	o
base	nn	o
type	nn	o
,	,	o
the	dt	o
non-blank	jj	o
names	vbz	o
of	in	o
methods	nns	o
bound	vbn	o
to	to	o
it	prp	o
must	md	o
be	vb	o
unique	jj	o
.	.	o
If	in	o
the	dt	o
base	nn	o
type	nn	o
is	vbz	o
a	dt	o
struct	nn	o
type	nn	o
,	,	o
the	dt	o
non-blank	jj	o
method	nn	o
and	cc	o
field	nn	o
names	vbz	o
must	md	o
be	vb	o
distinct	jj	o
.	.	o
Given	vbn	o
defined	vbn	o
type	nn	o
,	,	o
the	dt	o
declarations	nns	o
bind	vbp	o
the	dt	o
methods	nns	o
and	cc	o
,	,	o
with	in	o
receiver	nn	o
type	nn	o
,	,	o
to	to	o
the	dt	o
base	nn	o
type	nn	o
.	.	o
If	in	o
the	dt	o
receiver	nn	o
base	nn	o
type	nn	o
is	vbz	o
a	dt	o
generic	jj	o
type	nn	o
,	,	o
the	dt	o
receiver	nn	o
specification	nn	o
must	md	o
declare	vb	o
corresponding	jj	o
type	nn	o
parameters	nns	o
for	in	o
the	dt	o
method	nn	o
to	to	o
use	vb	o
.	.	o
This	dt	o
makes	vbz	o
the	dt	o
receiver	nn	o
type	nn	o
parameters	nns	o
available	jj	o
to	to	o
the	dt	o
method	nn	o
.	.	o
Syntactically	rb	o
,	,	o
this	dt	o
type	nn	o
parameter	nn	o
declaration	nn	o
looks	vbz	o
like	in	o
an	dt	o
instantiation	nn	o
of	in	o
the	dt	o
receiver	nn	o
base	nn	o
type	nn	o
,	,	o
except	vb	o
that	wdt	o
the	dt	o
type	nn	o
arguments	nns	o
are	vbp	o
the	dt	o
type	nn	o
parameters	nns	o
being	vbg	o
declared	vbn	o
,	,	o
one	nn	o
for	in	o
each	dt	o
type	nn	o
parameter	nn	o
of	in	o
the	dt	o
receiver	nn	o
base	nn	o
type	nn	o
.	.	o
The	dt	o
type	nn	o
parameter	nn	o
names	vbz	o
do	vbp	o
not	rb	o
need	md	o
to	to	o
match	vbp	o
their	prp$	o
corresponding	jj	o
parameter	nn	o
names	vbz	o
in	in	o
the	dt	o
receiver	nn	o
base	nn	o
type	nn	o
definition	nn	o
,	,	o
and	cc	o
all	pdt	o
non-blank	jj	o
parameter	nn	o
names	vbz	o
must	md	o
be	vb	o
unique	jj	o
in	in	o
the	dt	o
receiver	nn	o
parameter	nn	o
section	nn	o
and	cc	o
the	dt	o
method	nn	o
signature	nn	o
.	.	o
The	dt	o
receiver	nn	o
type	nn	o
parameter	nn	o
constraints	nns	o
are	vbp	o
implied	vbn	o
by	in	o
the	dt	o
receiver	nn	o
base	nn	o
type	nn	o
definition	nn	o
:	:	o
corresponding	jj	o
type	nn	o
parameters	nns	o
have	vb	o
corresponding	jj	o
constraints	nns	o
.	.	o
Expressions	nns	o
An	dt	o
expression	nn	o
specifies	vbz	o
the	dt	o
computation	nn	o
of	in	o
a	dt	o
value	nn	o
by	in	o
applying	vbg	o
operators	nns	o
and	cc	o
functions	nns	o
to	to	o
operands	nns	o
.	.	o
Operands	nns	o
Operands	nns	o
denote	vbp	o
the	dt	o
elementary	jj	o
values	nns	o
in	in	o
an	dt	o
expression	nn	o
.	.	o
An	dt	o
operand	nn	o
may	md	o
be	vb	o
a	dt	o
literal	jj	o
,	,	o
a	dt	o
(	(	o
possibly	rb	o
qualified	vbn	o
)	)	o
non-blank	jj	o
identifier	nn	o
denoting	vbg	o
a	dt	o
constant	nn	o
,	,	o
variable	jj	o
,	,	o
or	cc	o
function	nn	o
,	,	o
or	cc	o
a	dt	o
parenthesized	vbn	o
expression	nn	o
.	.	o
An	dt	o
operand	nn	o
name	nn	o
denoting	vbg	o
a	dt	o
generic	jj	o
function	nn	o
may	md	o
be	vb	o
followed	vbn	o
by	in	o
a	dt	o
list	nn	o
of	in	o
type	nn	o
arguments	nns	o
;	:	o
the	dt	o
resulting	vbg	o
operand	nn	o
is	vbz	o
an	dt	o
instantiated	vbn	o
function	nn	o
.	.	o
The	dt	o
blank	jj	o
identifier	nn	o
may	md	o
appear	vbp	o
as	in	o
an	dt	o
operand	nn	o
only	rb	o
on	in	o
the	dt	o
left-hand	jj	o
side	nn	o
of	in	o
an	dt	o
assignment	nn	o
.	.	o
Qualified	vbn	o
identifiers	nns	o
A	dt	o
qualified	jj	o
identifier	nn	o
is	vbz	o
an	dt	o
identifier	nn	o
qualified	jj	o
with	in	o
a	dt	o
package	nn	o
name	nn	o
prefix	nn	o
.	.	o
Both	cc	o
the	dt	o
package	nn	o
name	nn	o
and	cc	o
the	dt	o
identifier	nn	o
must	md	o
not	rb	o
be	vb	o
blank	jj	o
.	.	o
A	dt	o
qualified	jj	o
identifier	nn	o
accesses	vbz	o
an	dt	o
identifier	nn	o
in	in	o
a	dt	o
different	jj	o
package	nn	o
,	,	o
which	wdt	o
must	md	o
be	vb	o
imported	vbn	o
.	.	o
The	dt	o
identifier	nn	o
must	md	o
be	vb	o
exported	jj	o
and	cc	o
declared	vbn	o
in	in	o
the	dt	o
package	nn	o
block	nn	o
of	in	o
that	wdt	o
package	nn	o
.	.	o
Composite	jj	o
literals	nns	o
Composite	jj	o
literals	nns	o
construct	nn	o
new	jj	o
composite	jj	o
values	nns	o
each	dt	o
time	nn	o
they	prp	o
are	vbp	o
evaluated	vbn	o
.	.	o
They	prp	o
consist	vbp	o
of	in	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
literal	nn	o
followed	vbn	o
by	in	o
a	dt	o
brace-bound	jj	o
list	nn	o
of	in	o
elements	nns	o
.	.	o
Each	dt	o
element	nn	o
may	md	o
optionally	rb	o
be	vb	o
preceded	vbn	o
by	in	o
a	dt	o
corresponding	jj	o
key	nn	o
.	.	o
The	dt	o
LiteralType	nnp	b-gpe
's	pos	o
core	nn	o
type	nn	o
must	md	o
be	vb	o
a	dt	o
struct	nn	o
,	,	o
array	vb	o
,	,	o
slice	nn	o
,	,	o
or	cc	o
map	nn	o
type	nn	o
(	(	o
the	dt	o
grammar	nn	o
enforces	vbz	o
this	dt	o
constraint	nn	o
except	vb	o
when	wrb	o
the	dt	o
type	nn	o
is	vbz	o
given	vbn	o
as	in	o
a	dt	o
TypeName	nn	o
)	)	o
.	.	o
The	dt	o
types	nns	o
of	in	o
the	dt	o
elements	nns	o
and	cc	o
keys	nns	o
must	md	o
be	vb	o
assignable	jj	o
to	to	o
the	dt	o
respective	jj	o
field	nn	o
,	,	o
element	nn	o
,	,	o
and	cc	o
key	nn	o
types	nns	o
of	in	o
type	nn	o
;	:	o
there	ex	o
is	vbz	o
no	dt	o
additional	jj	o
conversion	nn	o
.	.	o
The	dt	o
key	nn	o
is	vbz	o
interpreted	vbn	o
as	in	o
a	dt	o
field	nn	o
name	nn	o
for	in	o
struct	nn	o
literals	nns	o
,	,	o
an	dt	o
index	nn	o
for	in	o
array	nn	o
and	cc	o
slice	nn	o
literals	nns	o
,	,	o
and	cc	o
a	dt	o
key	nn	o
for	in	o
map	nn	o
literals	nns	o
.	.	o
For	in	o
map	nn	o
literals	nns	o
,	,	o
all	pdt	o
elements	nns	o
must	md	o
have	vb	o
a	dt	o
key	nn	o
.	.	o
It	prp	o
is	vbz	o
an	dt	o
error	nn	o
to	to	o
specify	vb	o
multiple	nn	o
elements	nns	o
with	in	o
the	dt	o
same	jj	o
field	nn	o
name	nn	o
or	cc	o
constant	nn	o
key	nn	o
value	nn	o
.	.	o
For	in	o
non-constant	jj	o
map	nn	o
keys	nns	o
,	,	o
see	vbp	o
the	dt	o
section	nn	o
on	in	o
evaluation	nn	o
order	nn	o
.	.	o
For	in	o
struct	nn	o
literals	nns	o
the	dt	o
following	vbg	o
rules	nns	o
apply	vbp	o
:	:	o
A	dt	o
key	nn	o
must	md	o
be	vb	o
a	dt	o
field	nn	o
name	nn	o
declared	vbn	o
in	in	o
the	dt	o
struct	nn	o
type	nn	o
.	.	o
An	dt	o
element	nn	o
list	nn	o
that	wdt	o
does	vbz	o
not	rb	o
contain	vb	o
any	dt	o
keys	nns	o
must	md	o
list	nn	o
an	dt	o
element	nn	o
for	in	o
each	dt	o
struct	nn	o
field	nn	o
in	in	o
the	dt	o
order	nn	o
in	in	o
which	wdt	o
the	dt	o
fields	nns	o
are	vbp	o
declared	vbn	o
.	.	o
If	in	o
any	dt	o
element	nn	o
has	vbz	o
a	dt	o
key	nn	o
,	,	o
every	dt	o
element	nn	o
must	md	o
have	vb	o
a	dt	o
key	nn	o
.	.	o
An	dt	o
element	nn	o
list	nn	o
that	wdt	o
contains	vbz	o
keys	nns	o
does	vbz	o
not	rb	o
need	md	o
to	to	o
have	vb	o
an	dt	o
element	nn	o
for	in	o
each	dt	o
struct	nn	o
field	nn	o
.	.	o
Omitted	vbn	o
fields	nns	o
get	vbp	o
the	dt	o
zero	nn	o
value	nn	o
for	in	o
that	wdt	o
field	nn	o
.	.	o
A	dt	o
literal	nn	o
may	md	o
omit	vb	o
the	dt	o
element	nn	o
list	nn	o
;	:	o
such	jj	o
a	dt	o
literal	nn	o
evaluates	vbz	o
to	to	o
the	dt	o
zero	nn	o
value	nn	o
for	in	o
its	prp$	o
type	nn	o
.	.	o
It	prp	o
is	vbz	o
an	dt	o
error	nn	o
to	to	o
specify	vb	o
an	dt	o
element	nn	o
for	in	o
a	dt	o
non-exported	jj	o
field	nn	o
of	in	o
a	dt	o
struct	nn	o
belonging	vbg	o
to	to	o
a	dt	o
different	jj	o
package	nn	o
.	.	o
Given	vbn	o
the	dt	o
declarations	nns	o
one	nn	o
may	md	o
write	vb	o
For	in	o
array	nn	o
and	cc	o
slice	nn	o
literals	nns	o
the	dt	o
following	vbg	o
rules	nns	o
apply	vbp	o
:	:	o
Each	dt	o
element	nn	o
has	vbz	o
an	dt	o
associated	jj	o
integer	jj	o
index	nn	o
marking	vbg	o
its	prp$	o
position	nn	o
in	in	o
the	dt	o
array	nn	o
.	.	o
An	dt	o
element	nn	o
with	in	o
a	dt	o
key	nn	o
uses	nns	o
the	dt	o
key	nn	o
as	in	o
its	prp$	o
index	nn	o
.	.	o
The	dt	o
key	nn	o
must	md	o
be	vb	o
a	dt	o
non-negative	jj	o
constant	nn	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
;	:	o
and	cc	o
if	in	o
it	prp	o
is	vbz	o
typed	jj	o
it	prp	o
must	md	o
be	vb	o
of	in	o
integer	jj	o
type	nn	o
.	.	o
An	dt	o
element	nn	o
without	in	o
a	dt	o
key	nn	o
uses	nns	o
the	dt	o
previous	jj	o
element	nn	o
's	pos	o
index	nn	o
plus	cc	o
one	nn	o
.	.	o
If	in	o
the	dt	o
first	jj	o
element	nn	o
has	vbz	o
no	dt	o
key	nn	o
,	,	o
its	prp$	o
index	nn	o
is	vbz	o
zero	cd	o
.	.	o
Taking	vbg	o
the	dt	o
address	nn	o
of	in	o
a	dt	o
composite	jj	o
literal	nn	o
generates	vbz	o
a	dt	o
pointer	nn	o
to	to	o
a	dt	o
unique	jj	o
variable	nn	o
initialized	vbn	o
with	in	o
the	dt	o
literal	nn	o
's	pos	o
value	nn	o
.	.	o
Note	nn	o
that	wdt	o
the	dt	o
zero	nn	o
value	nn	o
for	in	o
a	dt	o
slice	nn	o
or	cc	o
map	nn	o
type	nn	o
is	vbz	o
not	rb	o
the	dt	o
same	jj	o
as	in	o
an	dt	o
initialized	vbn	o
but	cc	o
empty	jj	o
value	nn	o
of	in	o
the	dt	o
same	jj	o
type	nn	o
.	.	o
Consequently	rb	o
,	,	o
taking	vbg	o
the	dt	o
address	nn	o
of	in	o
an	dt	o
empty	jj	o
slice	nn	o
or	cc	o
map	nn	o
composite	jj	o
literal	nn	o
does	vbz	o
not	rb	o
have	vb	o
the	dt	o
same	jj	o
effect	nn	o
as	in	o
allocating	vbg	o
a	dt	o
new	jj	o
slice	nn	o
or	cc	o
map	nn	o
value	nn	o
with	in	o
new	jj	o
.	.	o
The	dt	o
length	nn	o
of	in	o
an	dt	o
array	nn	o
literal	nn	o
is	vbz	o
the	dt	o
length	nn	o
specified	vbn	o
in	in	o
the	dt	o
literal	nn	o
type	nn	o
.	.	o
If	in	o
fewer	jjr	o
elements	nns	o
than	in	o
the	dt	o
length	nn	o
are	vbp	o
provided	vbn	o
in	in	o
the	dt	o
literal	jj	o
,	,	o
the	dt	o
missing	jj	o
elements	nns	o
are	vbp	o
set	nn	o
to	to	o
the	dt	o
zero	nn	o
value	nn	o
for	in	o
the	dt	o
array	nn	o
element	nn	o
type	nn	o
.	.	o
It	prp	o
is	vbz	o
an	dt	o
error	nn	o
to	to	o
provide	vbp	o
elements	nns	o
with	in	o
index	nn	o
values	nns	o
outside	in	o
the	dt	o
index	nn	o
range	nn	o
of	in	o
the	dt	o
array	nn	o
.	.	o
The	dt	o
notation	nn	o
specifies	vbz	o
an	dt	o
array	nn	o
length	nn	o
equal	vb	o
to	to	o
the	dt	o
maximum	jj	o
element	nn	o
index	nn	o
plus	cc	o
one	nn	o
.	.	o
A	dt	o
slice	nn	o
literal	nn	o
describes	vbz	o
the	dt	o
entire	jj	o
underlying	jj	o
array	nn	o
literal	jj	o
.	.	o
Thus	nnp	o
the	dt	o
length	nn	o
and	cc	o
capacity	nn	o
of	in	o
a	dt	o
slice	nn	o
literal	nn	o
are	vbp	o
the	dt	o
maximum	jj	o
element	nn	o
index	nn	o
plus	cc	o
one	nn	o
.	.	o
A	dt	o
slice	nn	o
literal	nn	o
has	vbz	o
the	dt	o
form	nn	o
and	cc	o
is	vbz	o
shorthand	nn	o
for	in	o
a	dt	o
slice	nn	o
operation	nn	o
applied	vbd	o
to	to	o
an	dt	o
array	nn	o
:	:	o
Within	in	o
a	dt	o
composite	jj	o
literal	nn	o
of	in	o
array	vb	o
,	,	o
slice	nn	o
,	,	o
or	cc	o
map	nn	o
type	nn	o
,	,	o
elements	nns	o
or	cc	o
map	nn	o
keys	nns	o
that	wdt	o
are	vbp	o
themselves	prp	o
composite	jj	o
literals	nns	o
may	md	o
elide	vb	o
the	dt	o
respective	jj	o
literal	nn	o
type	nn	o
if	in	o
it	prp	o
is	vbz	o
identical	jj	o
to	to	o
the	dt	o
element	nn	o
or	cc	o
key	nn	o
type	nn	o
of	in	o
.	.	o
Similarly	rb	o
,	,	o
elements	nns	o
or	cc	o
keys	nns	o
that	wdt	o
are	vbp	o
addresses	nns	o
of	in	o
composite	jj	o
literals	nns	o
may	md	o
elide	vb	o
the	dt	o
when	wrb	o
the	dt	o
element	nn	o
or	cc	o
key	nn	o
type	nn	o
is	vbz	o
.	.	o
A	dt	o
parsing	jj	o
ambiguity	nn	o
arises	nns	o
when	wrb	o
a	dt	o
composite	jj	o
literal	nn	o
using	vbg	o
the	dt	o
TypeName	nnp	b-gpe
form	nn	o
of	in	o
the	dt	o
LiteralType	nnp	b-gpe
appears	vbz	o
as	in	o
an	dt	o
operand	nn	o
between	in	o
the	dt	o
keyword	nn	o
and	cc	o
the	dt	o
opening	nn	o
brace	nn	o
of	in	o
the	dt	o
block	nn	o
of	in	o
an	dt	o
"	nn	o
if	in	o
"	nnp	o
,	,	o
"	nn	o
for	in	o
"	nn	o
,	,	o
or	cc	o
"	nnp	o
switch	nn	o
"	nnp	o
statement	nn	o
,	,	o
and	cc	o
the	dt	o
composite	jj	o
literal	nn	o
is	vbz	o
not	rb	o
enclosed	vbn	o
in	in	o
parentheses	nns	o
,	,	o
square	jj	o
brackets	nns	o
,	,	o
or	cc	o
curly	rb	o
braces	nns	o
.	.	o
In	in	o
this	dt	o
rare	jj	o
case	nn	o
,	,	o
the	dt	o
opening	nn	o
brace	nn	o
of	in	o
the	dt	o
literal	nn	o
is	vbz	o
erroneously	rb	o
parsed	vbn	o
as	in	o
the	dt	o
one	nn	o
introducing	vbg	o
the	dt	o
block	nn	o
of	in	o
statements	nns	o
.	.	o
To	to	o
resolve	vb	o
the	dt	o
ambiguity	nn	o
,	,	o
the	dt	o
composite	jj	o
literal	nn	o
must	md	o
appear	vbp	o
within	in	o
parentheses	nns	o
.	.	o
Examples	nns	o
of	in	o
valid	jj	o
array	vb	o
,	,	o
slice	nn	o
,	,	o
and	cc	o
map	nn	o
literals	nns	o
:	:	o
Function	nnp	b-person
literals	nns	o
A	dt	o
function	nn	o
literal	nn	o
represents	vbz	o
an	dt	o
anonymous	jj	o
function	nn	o
.	.	o
Function	nnp	b-person
literals	nns	o
cannot	vbp	o
declare	vb	o
type	nn	o
parameters	nns	o
.	.	o
A	dt	o
function	nn	o
literal	nn	o
can	md	o
be	vb	o
assigned	vbn	o
to	to	o
a	dt	o
variable	nn	o
or	cc	o
invoked	vbn	o
directly	rb	o
.	.	o
Function	nnp	b-person
literals	nns	o
are	vbp	o
closures	nns	o
:	:	o
they	prp	o
may	md	o
refer	vb	o
to	to	o
variables	nns	o
defined	vbn	o
in	in	o
a	dt	o
surrounding	vbg	o
function	nn	o
.	.	o
Those	dt	o
variables	nns	o
are	vbp	o
then	rb	o
shared	vbn	o
between	in	o
the	dt	o
surrounding	vbg	o
function	nn	o
and	cc	o
the	dt	o
function	nn	o
literal	jj	o
,	,	o
and	cc	o
they	prp	o
survive	vbp	o
as	in	o
long	rb	o
as	in	o
they	prp	o
are	vbp	o
accessible	jj	o
.	.	o
Primary	jj	o
expressions	nns	o
Primary	jj	o
expressions	nns	o
are	vbp	o
the	dt	o
operands	nns	o
for	in	o
unary	jj	o
and	cc	o
binary	jj	o
expressions	nns	o
.	.	o
Selectors	nns	o
[	vbp	o
This	dt	o
section	nn	o
is	vbz	o
missing	jj	o
rules	nns	o
for	in	o
x.f	nn	o
where	wrb	o
x	nn	o
's	pos	o
type	nn	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
and	cc	o
f	nn	o
is	vbz	o
a	dt	o
field	nn	o
.	.	o
]	nn	o
For	in	o
a	dt	o
primary	jj	o
expression	nn	o
that	wdt	o
is	vbz	o
not	rb	o
a	dt	o
package	nn	o
name	nn	o
,	,	o
the	dt	o
selector	nn	o
expression	nn	o
denotes	vbz	o
the	dt	o
field	nn	o
or	cc	o
method	nn	o
of	in	o
the	dt	o
value	nn	o
(	(	o
or	cc	o
sometimes	rb	o
;	:	o
see	vbp	o
below	in	o
)	)	o
.	.	o
The	dt	o
identifier	nn	o
is	vbz	o
called	vbd	o
the	dt	o
(	(	o
field	nn	o
or	cc	o
method	nn	o
)	)	o
selector	nn	o
;	:	o
it	prp	o
must	md	o
not	rb	o
be	vb	o
the	dt	o
blank	jj	o
identifier	nn	o
.	.	o
The	dt	o
type	nn	o
of	in	o
the	dt	o
selector	nn	o
expression	nn	o
is	vbz	o
the	dt	o
type	nn	o
of	in	o
.	.	o
If	in	o
is	vbz	o
a	dt	o
package	nn	o
name	nn	o
,	,	o
see	vbp	o
the	dt	o
section	nn	o
on	in	o
qualified	jj	o
identifiers	nns	o
.	.	o
A	dt	o
selector	nn	o
may	md	o
denote	vbp	o
a	dt	o
field	nn	o
or	cc	o
method	nn	o
of	in	o
a	dt	o
type	nn	o
,	,	o
or	cc	o
it	prp	o
may	md	o
refer	vb	o
to	to	o
a	dt	o
field	nn	o
or	cc	o
method	nn	o
of	in	o
a	dt	o
nested	jj	o
embedded	jj	o
field	nn	o
of	in	o
.	.	o
The	dt	o
number	nn	o
of	in	o
embedded	jj	o
fields	nns	o
traversed	vbd	o
to	to	o
reach	vb	o
is	vbz	o
called	vbd	o
its	prp$	o
depth	nn	o
in	in	o
.	.	o
The	dt	o
depth	nn	o
of	in	o
a	dt	o
field	nn	o
or	cc	o
method	nn	o
declared	vbn	o
in	in	o
is	vbz	o
zero	cd	o
.	.	o
The	dt	o
depth	nn	o
of	in	o
a	dt	o
field	nn	o
or	cc	o
method	nn	o
declared	vbn	o
in	in	o
an	dt	o
embedded	jj	o
field	nn	o
in	in	o
is	vbz	o
the	dt	o
depth	nn	o
of	in	o
in	in	o
plus	cc	o
one	nn	o
.	.	o
The	dt	o
following	vbg	o
rules	nns	o
apply	vbp	o
to	to	o
selectors	nns	o
:	:	o
For	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
or	cc	o
where	wrb	o
is	vbz	o
not	rb	o
a	dt	o
pointer	nn	o
or	cc	o
interface	nn	o
type	nn	o
,	,	o
denotes	vbz	o
the	dt	o
field	nn	o
or	cc	o
method	nn	o
at	in	o
the	dt	o
shallowest	nn	o
depth	nn	o
in	in	o
where	wrb	o
there	ex	o
is	vbz	o
such	jj	o
an	dt	o
.	.	o
If	in	o
there	ex	o
is	vbz	o
not	rb	o
exactly	rb	o
one	nn	o
with	in	o
shallowest	nn	o
depth	nn	o
,	,	o
the	dt	o
selector	nn	o
expression	nn	o
is	vbz	o
illegal	jj	o
.	.	o
For	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
where	wrb	o
is	vbz	o
an	dt	o
interface	nn	o
type	nn	o
,	,	o
denotes	vbz	o
the	dt	o
actual	jj	o
method	nn	o
with	in	o
name	nn	o
of	in	o
the	dt	o
dynamic	jj	o
value	nn	o
of	in	o
.	.	o
If	in	o
there	ex	o
is	vbz	o
no	dt	o
method	nn	o
with	in	o
name	nn	o
in	in	o
the	dt	o
method	nn	o
set	nn	o
of	in	o
,	,	o
the	dt	o
selector	nn	o
expression	nn	o
is	vbz	o
illegal	jj	o
.	.	o
As	in	o
an	dt	o
exception	nn	o
,	,	o
if	in	o
the	dt	o
type	nn	o
of	in	o
is	vbz	o
a	dt	o
defined	vbn	o
pointer	nn	o
type	nn	o
and	cc	o
is	vbz	o
a	dt	o
valid	jj	o
selector	nn	o
expression	nn	o
denoting	vbg	o
a	dt	o
field	nn	o
(	(	o
but	cc	o
not	rb	o
a	dt	o
method	nn	o
)	)	o
,	,	o
is	vbz	o
shorthand	nn	o
for	in	o
.	.	o
In	in	o
all	pdt	o
other	jj	o
cases	nns	o
,	,	o
is	vbz	o
illegal	jj	o
.	.	o
If	in	o
is	vbz	o
of	in	o
pointer	nn	o
type	nn	o
and	cc	o
has	vbz	o
the	dt	o
value	nn	o
and	cc	o
denotes	vbz	o
a	dt	o
struct	nn	o
field	nn	o
,	,	o
assigning	vbg	o
to	to	o
or	cc	o
evaluating	vbg	o
causes	vbz	o
a	dt	o
run-time	jj	o
panic	nn	o
.	.	o
If	in	o
is	vbz	o
of	in	o
interface	nn	o
type	nn	o
and	cc	o
has	vbz	o
the	dt	o
value	nn	o
,	,	o
calling	vbg	o
or	cc	o
evaluating	vbg	o
the	dt	o
method	nn	o
causes	vbz	o
a	dt	o
run-time	jj	o
panic	nn	o
.	.	o
For	in	o
example	nn	o
,	,	o
given	vbn	o
the	dt	o
declarations	nns	o
:	:	o
one	nn	o
may	md	o
write	vb	o
:	:	o
but	cc	o
the	dt	o
following	vbg	o
is	vbz	o
invalid	jj	o
:	:	o
Method	nnp	b-gpe
expressions	nns	o
If	in	o
is	vbz	o
in	in	o
the	dt	o
method	nn	o
set	nn	o
of	in	o
type	nn	o
,	,	o
is	vbz	o
a	dt	o
function	nn	o
that	wdt	o
is	vbz	o
callable	jj	o
as	in	o
a	dt	o
regular	jj	o
function	nn	o
with	in	o
the	dt	o
same	jj	o
arguments	nns	o
as	in	o
prefixed	vbn	o
by	in	o
an	dt	o
additional	jj	o
argument	nn	o
that	wdt	o
is	vbz	o
the	dt	o
receiver	nn	o
of	in	o
the	dt	o
method	nn	o
.	.	o
Consider	vb	o
a	dt	o
struct	nn	o
type	nn	o
with	in	o
two	cd	o
methods	nns	o
,	,	o
,	,	o
whose	wp$	o
receiver	nn	o
is	vbz	o
of	in	o
type	nn	o
,	,	o
and	cc	o
,	,	o
whose	wp$	o
receiver	nn	o
is	vbz	o
of	in	o
type	nn	o
.	.	o
The	dt	o
expression	nn	o
yields	nns	o
a	dt	o
function	nn	o
equivalent	jj	o
to	to	o
but	cc	o
with	in	o
an	dt	o
explicit	jj	o
receiver	nn	o
as	in	o
its	prp$	o
first	jj	o
argument	nn	o
;	:	o
it	prp	o
has	vbz	o
signature	nn	o
That	dt	o
function	nn	o
may	md	o
be	vb	o
called	vbd	o
normally	rb	o
with	in	o
an	dt	o
explicit	jj	o
receiver	nn	o
,	,	o
so	rb	o
these	dt	o
five	cd	o
invocations	nns	o
are	vbp	o
equivalent	jj	o
:	:	o
Similarly	rb	o
,	,	o
the	dt	o
expression	nn	o
yields	nns	o
a	dt	o
function	nn	o
value	nn	o
representing	vbg	o
with	in	o
signature	nn	o
For	in	o
a	dt	o
method	nn	o
with	in	o
a	dt	o
value	nn	o
receiver	nn	o
,	,	o
one	nn	o
can	md	o
derive	vb	o
a	dt	o
function	nn	o
with	in	o
an	dt	o
explicit	jj	o
pointer	nn	o
receiver	nn	o
,	,	o
so	rb	o
yields	nns	o
a	dt	o
function	nn	o
value	nn	o
representing	vbg	o
with	in	o
signature	nn	o
Such	jj	o
a	dt	o
function	nn	o
indirects	vbz	o
through	in	o
the	dt	o
receiver	nn	o
to	to	o
create	vb	o
a	dt	o
value	nn	o
to	to	o
pass	vb	o
as	in	o
the	dt	o
receiver	nn	o
to	to	o
the	dt	o
underlying	jj	o
method	nn	o
;	:	o
the	dt	o
method	nn	o
does	vbz	o
not	rb	o
overwrite	vb	o
the	dt	o
value	nn	o
whose	wp$	o
address	nn	o
is	vbz	o
passed	vbd	o
in	in	o
the	dt	o
function	nn	o
call	nn	o
.	.	o
The	dt	o
final	jj	o
case	nn	o
,	,	o
a	dt	o
value-receiver	jj	o
function	nn	o
for	in	o
a	dt	o
pointer-receiver	jj	o
method	nn	o
,	,	o
is	vbz	o
illegal	jj	o
because	in	o
pointer-receiver	jj	o
methods	nns	o
are	vbp	o
not	rb	o
in	in	o
the	dt	o
method	nn	o
set	nn	o
of	in	o
the	dt	o
value	nn	o
type	nn	o
.	.	o
Function	nnp	b-person
values	nns	o
derived	vbn	o
from	in	o
methods	nns	o
are	vbp	o
called	vbd	o
with	in	o
function	nn	o
call	nn	o
syntax	nn	o
;	:	o
the	dt	o
receiver	nn	o
is	vbz	o
provided	vbn	o
as	in	o
the	dt	o
first	jj	o
argument	nn	o
to	to	o
the	dt	o
call	nn	o
.	.	o
That	dt	o
is	vbz	o
,	,	o
given	vbn	o
,	,	o
is	vbz	o
invoked	vbn	o
as	in	o
not	rb	o
.	.	o
To	to	o
construct	nn	o
a	dt	o
function	nn	o
that	wdt	o
binds	vbz	o
the	dt	o
receiver	nn	o
,	,	o
use	vbp	o
a	dt	o
function	nn	o
literal	nn	o
or	cc	o
method	nn	o
value	nn	o
.	.	o
It	prp	o
is	vbz	o
legal	jj	o
to	to	o
derive	vb	o
a	dt	o
function	nn	o
value	nn	o
from	in	o
a	dt	o
method	nn	o
of	in	o
an	dt	o
interface	nn	o
type	nn	o
.	.	o
The	dt	o
resulting	vbg	o
function	nn	o
takes	vbz	o
an	dt	o
explicit	jj	o
receiver	nn	o
of	in	o
that	wdt	o
interface	nn	o
type	nn	o
.	.	o
Method	nnp	b-gpe
values	nns	o
If	in	o
the	dt	o
expression	nn	o
has	vbz	o
static	jj	o
type	nn	o
and	cc	o
is	vbz	o
in	in	o
the	dt	o
method	nn	o
set	nn	o
of	in	o
type	nn	o
,	,	o
is	vbz	o
called	vbd	o
a	dt	o
method	nn	o
value	nn	o
.	.	o
The	dt	o
method	nn	o
value	nn	o
is	vbz	o
a	dt	o
function	nn	o
value	nn	o
that	wdt	o
is	vbz	o
callable	jj	o
with	in	o
the	dt	o
same	jj	o
arguments	nns	o
as	in	o
a	dt	o
method	nn	o
call	nn	o
of	in	o
.	.	o
The	dt	o
expression	nn	o
is	vbz	o
evaluated	vbn	o
and	cc	o
saved	vbd	o
during	in	o
the	dt	o
evaluation	nn	o
of	in	o
the	dt	o
method	nn	o
value	nn	o
;	:	o
the	dt	o
saved	vbd	o
copy	nn	o
is	vbz	o
then	rb	o
used	vbn	o
as	in	o
the	dt	o
receiver	nn	o
in	in	o
any	dt	o
calls	nns	o
,	,	o
which	wdt	o
may	md	o
be	vb	o
executed	vbn	o
later	rb	o
.	.	o
The	dt	o
type	nn	o
may	md	o
be	vb	o
an	dt	o
interface	nn	o
or	cc	o
non-interface	jj	o
type	nn	o
.	.	o
As	in	o
in	in	o
the	dt	o
discussion	nn	o
of	in	o
method	nn	o
expressions	nns	o
above	in	o
,	,	o
consider	vb	o
a	dt	o
struct	nn	o
type	nn	o
with	in	o
two	cd	o
methods	nns	o
,	,	o
,	,	o
whose	wp$	o
receiver	nn	o
is	vbz	o
of	in	o
type	nn	o
,	,	o
and	cc	o
,	,	o
whose	wp$	o
receiver	nn	o
is	vbz	o
of	in	o
type	nn	o
.	.	o
The	dt	o
expression	nn	o
yields	nns	o
a	dt	o
function	nn	o
value	nn	o
of	in	o
type	nn	o
These	dt	o
two	cd	o
invocations	nns	o
are	vbp	o
equivalent	jj	o
:	:	o
Similarly	rb	o
,	,	o
the	dt	o
expression	nn	o
yields	nns	o
a	dt	o
function	nn	o
value	nn	o
of	in	o
type	nn	o
As	in	o
with	in	o
selectors	nns	o
,	,	o
a	dt	o
reference	nn	o
to	to	o
a	dt	o
non-interface	jj	o
method	nn	o
with	in	o
a	dt	o
value	nn	o
receiver	nn	o
using	vbg	o
a	dt	o
pointer	nn	o
will	md	o
automatically	rb	o
dereference	vb	o
that	wdt	o
pointer	nn	o
:	:	o
is	vbz	o
equivalent	jj	o
to	to	o
.	.	o
As	in	o
with	in	o
method	nn	o
calls	nns	o
,	,	o
a	dt	o
reference	nn	o
to	to	o
a	dt	o
non-interface	jj	o
method	nn	o
with	in	o
a	dt	o
pointer	nn	o
receiver	nn	o
using	vbg	o
an	dt	o
addressable	jj	o
value	nn	o
will	md	o
automatically	rb	o
take	vb	o
the	dt	o
address	nn	o
of	in	o
that	wdt	o
value	nn	o
:	:	o
is	vbz	o
equivalent	jj	o
to	to	o
.	.	o
Although	in	o
the	dt	o
examples	nns	o
above	in	o
use	vbp	o
non-interface	jj	o
types	nns	o
,	,	o
it	prp	o
is	vbz	o
also	rb	o
legal	jj	o
to	to	o
create	vb	o
a	dt	o
method	nn	o
value	nn	o
from	in	o
a	dt	o
value	nn	o
of	in	o
interface	nn	o
type	nn	o
.	.	o
Index	nnp	b-gpe
expressions	nns	o
A	dt	o
primary	jj	o
expression	nn	o
of	in	o
the	dt	o
form	nn	o
denotes	vbz	o
the	dt	o
element	nn	o
of	in	o
the	dt	o
array	vb	o
,	,	o
pointer	nn	o
to	to	o
array	vb	o
,	,	o
slice	nn	o
,	,	o
string	vbg	o
or	cc	o
map	nn	o
indexed	vbn	o
by	in	o
.	.	o
The	dt	o
value	nn	o
is	vbz	o
called	vbd	o
the	dt	o
index	nn	o
or	cc	o
map	nn	o
key	nn	o
,	,	o
respectively	rb	o
.	.	o
The	dt	o
following	vbg	o
rules	nns	o
apply	vbp	o
:	:	o
If	in	o
is	vbz	o
not	rb	o
a	dt	o
map	nn	o
:	:	o
the	dt	o
index	nn	o
must	md	o
be	vb	o
an	dt	o
untyped	jj	o
constant	nn	o
or	cc	o
its	prp$	o
core	nn	o
type	nn	o
must	md	o
be	vb	o
an	dt	o
integer	jj	o
a	dt	o
constant	nn	o
index	nn	o
must	md	o
be	vb	o
non-negative	jj	o
and	cc	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
a	dt	o
constant	nn	o
index	nn	o
that	wdt	o
is	vbz	o
untyped	jj	o
is	vbz	o
given	vbn	o
type	nn	o
the	dt	o
index	nn	o
is	vbz	o
in	in	o
range	nn	o
if	in	o
,	,	o
otherwise	rb	o
it	prp	o
is	vbz	o
out	in	o
of	in	o
range	nn	o
For	in	o
of	in	o
array	nn	o
type	nn	o
:	:	o
a	dt	o
constant	nn	o
index	nn	o
must	md	o
be	vb	o
in	in	o
range	nn	o
if	in	o
is	vbz	o
out	in	o
of	in	o
range	nn	o
at	in	o
run	jj	o
time	nn	o
,	,	o
a	dt	o
run-time	jj	o
panic	nn	o
occurs	nn	o
is	vbz	o
the	dt	o
array	nn	o
element	nn	o
at	in	o
index	nn	o
and	cc	o
the	dt	o
type	nn	o
of	in	o
is	vbz	o
the	dt	o
element	nn	o
type	nn	o
of	in	o
For	in	o
of	in	o
pointer	nn	o
to	to	o
array	nn	o
type	nn	o
:	:	o
is	vbz	o
shorthand	nn	o
for	in	o
For	in	o
of	in	o
slice	nn	o
type	nn	o
:	:	o
if	in	o
is	vbz	o
out	in	o
of	in	o
range	nn	o
at	in	o
run	jj	o
time	nn	o
,	,	o
a	dt	o
run-time	jj	o
panic	nn	o
occurs	nn	o
is	vbz	o
the	dt	o
slice	nn	o
element	nn	o
at	in	o
index	nn	o
and	cc	o
the	dt	o
type	nn	o
of	in	o
is	vbz	o
the	dt	o
element	nn	o
type	nn	o
of	in	o
For	in	o
of	in	o
string	vbg	o
type	nn	o
:	:	o
a	dt	o
constant	nn	o
index	nn	o
must	md	o
be	vb	o
in	in	o
range	nn	o
if	in	o
the	dt	o
string	vbg	o
is	vbz	o
also	rb	o
constant	nn	o
if	in	o
is	vbz	o
out	in	o
of	in	o
range	nn	o
at	in	o
run	jj	o
time	nn	o
,	,	o
a	dt	o
run-time	jj	o
panic	nn	o
occurs	nn	o
is	vbz	o
the	dt	o
non-constant	jj	o
byte	nn	o
value	nn	o
at	in	o
index	nn	o
and	cc	o
the	dt	o
type	nn	o
of	in	o
is	vbz	o
may	md	o
not	rb	o
be	vb	o
assigned	vbn	o
to	to	o
For	in	o
of	in	o
map	nn	o
type	nn	o
:	:	o
's	pos	o
type	nn	o
must	md	o
be	vb	o
assignable	jj	o
to	to	o
the	dt	o
key	nn	o
type	nn	o
of	in	o
if	in	o
the	dt	o
map	nn	o
contains	vbz	o
an	dt	o
entry	nn	o
with	in	o
key	nn	o
,	,	o
is	vbz	o
the	dt	o
map	nn	o
element	nn	o
with	in	o
key	nn	o
and	cc	o
the	dt	o
type	nn	o
of	in	o
is	vbz	o
the	dt	o
element	nn	o
type	nn	o
of	in	o
if	in	o
the	dt	o
map	nn	o
is	vbz	o
or	cc	o
does	vbz	o
not	rb	o
contain	vb	o
such	jj	o
an	dt	o
entry	nn	o
,	,	o
is	vbz	o
the	dt	o
zero	nn	o
value	nn	o
for	in	o
the	dt	o
element	nn	o
type	nn	o
of	in	o
For	in	o
of	in	o
type	nn	o
parameter	nn	o
type	nn	o
:	:	o
must	md	o
have	vb	o
specific	jj	o
types	nns	o
.	.	o
The	dt	o
index	nn	o
expression	nn	o
must	md	o
be	vb	o
valid	jj	o
for	in	o
values	nns	o
of	in	o
all	pdt	o
specific	jj	o
types	nns	o
of	in	o
.	.	o
The	dt	o
element	nn	o
types	nns	o
of	in	o
all	pdt	o
specific	jj	o
types	nns	o
of	in	o
must	md	o
be	vb	o
identical	jj	o
.	.	o
In	in	o
this	dt	o
context	nn	o
,	,	o
the	dt	o
element	nn	o
type	nn	o
of	in	o
a	dt	o
string	vbg	o
type	nn	o
is	vbz	o
.	.	o
If	in	o
there	ex	o
is	vbz	o
a	dt	o
map	nn	o
type	nn	o
among	in	o
the	dt	o
specific	jj	o
types	nns	o
of	in	o
,	,	o
all	pdt	o
specific	jj	o
types	nns	o
must	md	o
be	vb	o
map	nn	o
types	nns	o
,	,	o
and	cc	o
the	dt	o
respective	jj	o
key	nn	o
types	nns	o
must	md	o
be	vb	o
all	pdt	o
identical	jj	o
.	.	o
is	vbz	o
the	dt	o
array	vb	o
,	,	o
slice	nn	o
,	,	o
or	cc	o
string	vbg	o
element	nn	o
at	in	o
index	nn	o
,	,	o
or	cc	o
the	dt	o
map	nn	o
element	nn	o
with	in	o
key	nn	o
of	in	o
the	dt	o
type	nn	o
argument	nn	o
that	wdt	o
is	vbz	o
instantiated	vbn	o
with	in	o
,	,	o
and	cc	o
the	dt	o
type	nn	o
of	in	o
is	vbz	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
(	(	o
identical	jj	o
)	)	o
element	nn	o
types	nns	o
.	.	o
may	md	o
not	rb	o
be	vb	o
assigned	vbn	o
to	to	o
if	in	o
the	dt	o
specific	jj	o
types	nns	o
of	in	o
include	vb	o
string	vbg	o
types	nns	o
.	.	o
Otherwise	vb	o
is	vbz	o
illegal	jj	o
.	.	o
An	dt	o
index	nn	o
expression	nn	o
on	in	o
a	dt	o
map	nn	o
of	in	o
type	nn	o
used	vbn	o
in	in	o
an	dt	o
assignment	nn	o
or	cc	o
initialization	nn	o
of	in	o
the	dt	o
special	jj	o
form	nn	o
yields	nns	o
an	dt	o
additional	jj	o
untyped	jj	o
boolean	jj	o
value	nn	o
.	.	o
The	dt	o
value	nn	o
of	in	o
is	vbz	o
if	in	o
the	dt	o
key	nn	o
is	vbz	o
present	vb	o
in	in	o
the	dt	o
map	nn	o
,	,	o
and	cc	o
otherwise	rb	o
.	.	o
Assigning	vbg	o
to	to	o
an	dt	o
element	nn	o
of	in	o
a	dt	o
map	nn	o
causes	vbz	o
a	dt	o
run-time	jj	o
panic	nn	o
.	.	o
Slice	nnp	o
expressions	nns	o
Slice	nnp	o
expressions	nns	o
construct	nn	o
a	dt	o
substring	nn	o
or	cc	o
slice	nn	o
from	in	o
a	dt	o
string	nn	o
,	,	o
array	vb	o
,	,	o
pointer	nn	o
to	to	o
array	vb	o
,	,	o
or	cc	o
slice	nn	o
.	.	o
There	ex	o
are	vbp	o
two	cd	o
variants	nns	o
:	:	o
a	dt	o
simple	nn	o
form	nn	o
that	wdt	o
specifies	vbz	o
a	dt	o
low	jj	o
and	cc	o
high	jj	o
bound	nn	o
,	,	o
and	cc	o
a	dt	o
full	jj	o
form	nn	o
that	wdt	o
also	rb	o
specifies	vbz	o
a	dt	o
bound	vbn	o
on	in	o
the	dt	o
capacity	nn	o
.	.	o
Simple	jj	o
slice	nn	o
expressions	nns	o
The	dt	o
primary	jj	o
expression	nn	o
constructs	vbz	o
a	dt	o
substring	nn	o
or	cc	o
slice	nn	o
.	.	o
The	dt	o
core	nn	o
type	nn	o
of	in	o
must	md	o
be	vb	o
a	dt	o
string	nn	o
,	,	o
array	vb	o
,	,	o
pointer	nn	o
to	to	o
array	vb	o
,	,	o
or	cc	o
slice	nn	o
.	.	o
The	dt	o
indices	nns	o
and	cc	o
select	nn	o
which	wdt	o
elements	nns	o
of	in	o
operand	nn	o
appear	vbp	o
in	in	o
the	dt	o
result	nn	o
.	.	o
The	dt	o
result	nn	o
has	vbz	o
indices	nns	o
starting	vbg	o
at	in	o
0	-none-	o
and	cc	o
length	nn	o
equal	vb	o
to	to	o
-	-	o
.	.	o
After	in	o
slicing	vbg	o
the	dt	o
array	nn	o
the	dt	o
slice	nn	o
has	vbz	o
type	nn	o
,	,	o
length	nn	o
3	cd	o
,	,	o
capacity	nn	o
4	cd	o
,	,	o
and	cc	o
elements	nns	o
For	in	o
convenience	nn	o
,	,	o
any	dt	o
of	in	o
the	dt	o
indices	nns	o
may	md	o
be	vb	o
omitted	vbn	o
.	.	o
A	dt	o
missing	jj	o
index	nn	o
defaults	vbz	o
to	to	o
zero	cd	o
;	:	o
a	dt	o
missing	jj	o
index	nn	o
defaults	vbz	o
to	to	o
the	dt	o
length	nn	o
of	in	o
the	dt	o
sliced	jj	o
operand	nn	o
:	:	o
If	in	o
is	vbz	o
a	dt	o
pointer	nn	o
to	to	o
an	dt	o
array	vb	o
,	,	o
is	vbz	o
shorthand	nn	o
for	in	o
.	.	o
For	in	o
arrays	nns	o
or	cc	o
strings	nns	o
,	,	o
the	dt	o
indices	nns	o
are	vbp	o
in	in	o
range	nn	o
if	in	o
<=	rb	o
<=	rb	o
<=	rb	o
,	,	o
otherwise	rb	o
they	prp	o
are	vbp	o
out	in	o
of	in	o
range	nn	o
.	.	o
For	in	o
slices	nns	o
,	,	o
the	dt	o
upper	jj	o
index	nn	o
bound	vbn	o
is	vbz	o
the	dt	o
slice	nn	o
capacity	nn	o
rather	rb	o
than	in	o
the	dt	o
length	nn	o
.	.	o
A	dt	o
constant	nn	o
index	nn	o
must	md	o
be	vb	o
non-negative	jj	o
and	cc	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
;	:	o
for	in	o
arrays	nns	o
or	cc	o
constant	nn	o
strings	nns	o
,	,	o
constant	nn	o
indices	nns	o
must	md	o
also	rb	o
be	vb	o
in	in	o
range	nn	o
.	.	o
If	in	o
both	dt	o
indices	nns	o
are	vbp	o
constant	nn	o
,	,	o
they	prp	o
must	md	o
satisfy	vbp	o
.	.	o
If	in	o
the	dt	o
indices	nns	o
are	vbp	o
out	in	o
of	in	o
range	nn	o
at	in	o
run	jj	o
time	nn	o
,	,	o
a	dt	o
run-time	jj	o
panic	nn	o
occurs	nns	o
.	.	o
Except	in	o
for	in	o
untyped	jj	o
strings	nns	o
,	,	o
if	in	o
the	dt	o
sliced	jj	o
operand	nn	o
is	vbz	o
a	dt	o
string	vbg	o
or	cc	o
slice	nn	o
,	,	o
the	dt	o
result	nn	o
of	in	o
the	dt	o
slice	nn	o
operation	nn	o
is	vbz	o
a	dt	o
non-constant	jj	o
value	nn	o
of	in	o
the	dt	o
same	jj	o
type	nn	o
as	in	o
the	dt	o
operand	nn	o
.	.	o
For	in	o
untyped	jj	o
string	vbg	o
operands	nns	o
the	dt	o
result	nn	o
is	vbz	o
a	dt	o
non-constant	jj	o
value	nn	o
of	in	o
type	nn	o
.	.	o
If	in	o
the	dt	o
sliced	jj	o
operand	nn	o
is	vbz	o
an	dt	o
array	vb	o
,	,	o
it	prp	o
must	md	o
be	vb	o
addressable	jj	o
and	cc	o
the	dt	o
result	nn	o
of	in	o
the	dt	o
slice	nn	o
operation	nn	o
is	vbz	o
a	dt	o
slice	nn	o
with	in	o
the	dt	o
same	jj	o
element	nn	o
type	nn	o
as	in	o
the	dt	o
array	nn	o
.	.	o
If	in	o
the	dt	o
sliced	jj	o
operand	nn	o
of	in	o
a	dt	o
valid	jj	o
slice	nn	o
expression	nn	o
is	vbz	o
a	dt	o
slice	nn	o
,	,	o
the	dt	o
result	nn	o
is	vbz	o
a	dt	o
slice	nn	o
.	.	o
Otherwise	rb	o
,	,	o
if	in	o
the	dt	o
result	nn	o
is	vbz	o
a	dt	o
slice	nn	o
,	,	o
it	prp	o
shares	nns	o
its	prp$	o
underlying	jj	o
array	nn	o
with	in	o
the	dt	o
operand	nn	o
.	.	o
Full	nnp	o
slice	nn	o
expressions	nns	o
The	dt	o
primary	jj	o
expression	nn	o
constructs	vbz	o
a	dt	o
slice	nn	o
of	in	o
the	dt	o
same	jj	o
type	nn	o
,	,	o
and	cc	o
with	in	o
the	dt	o
same	jj	o
length	nn	o
and	cc	o
elements	nns	o
as	in	o
the	dt	o
simple	nn	o
slice	nn	o
expression	nn	o
.	.	o
Additionally	rb	o
,	,	o
it	prp	o
controls	vbz	o
the	dt	o
resulting	vbg	o
slice	nn	o
's	pos	o
capacity	nn	o
by	in	o
setting	vbg	o
it	prp	o
to	to	o
.	.	o
Only	rb	o
the	dt	o
first	jj	o
index	nn	o
may	md	o
be	vb	o
omitted	vbn	o
;	:	o
it	prp	o
defaults	vbz	o
to	to	o
0	-none-	o
.	.	o
The	dt	o
core	nn	o
type	nn	o
of	in	o
must	md	o
be	vb	o
an	dt	o
array	vb	o
,	,	o
pointer	nn	o
to	to	o
array	vb	o
,	,	o
or	cc	o
slice	nn	o
(	(	o
but	cc	o
not	rb	o
a	dt	o
string	nn	o
)	)	o
.	.	o
After	in	o
slicing	vbg	o
the	dt	o
array	nn	o
the	dt	o
slice	nn	o
has	vbz	o
type	nn	o
,	,	o
length	nn	o
2	cd	o
,	,	o
capacity	nn	o
4	cd	o
,	,	o
and	cc	o
elements	nns	o
As	in	o
for	in	o
simple	nn	o
slice	nn	o
expressions	nns	o
,	,	o
if	in	o
is	vbz	o
a	dt	o
pointer	nn	o
to	to	o
an	dt	o
array	vb	o
,	,	o
is	vbz	o
shorthand	nn	o
for	in	o
.	.	o
If	in	o
the	dt	o
sliced	jj	o
operand	nn	o
is	vbz	o
an	dt	o
array	vb	o
,	,	o
it	prp	o
must	md	o
be	vb	o
addressable	jj	o
.	.	o
The	dt	o
indices	nns	o
are	vbp	o
in	in	o
range	nn	o
if	in	o
,	,	o
otherwise	rb	o
they	prp	o
are	vbp	o
out	in	o
of	in	o
range	nn	o
.	.	o
A	dt	o
constant	nn	o
index	nn	o
must	md	o
be	vb	o
non-negative	jj	o
and	cc	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
;	:	o
for	in	o
arrays	nns	o
,	,	o
constant	nn	o
indices	nns	o
must	md	o
also	rb	o
be	vb	o
in	in	o
range	nn	o
.	.	o
If	in	o
multiple	nn	o
indices	nns	o
are	vbp	o
constant	nn	o
,	,	o
the	dt	o
constants	nns	o
that	wdt	o
are	vbp	o
present	vb	o
must	md	o
be	vb	o
in	in	o
range	nn	o
relative	vbp	o
to	to	o
each	dt	o
other	jj	o
.	.	o
If	in	o
the	dt	o
indices	nns	o
are	vbp	o
out	in	o
of	in	o
range	nn	o
at	in	o
run	jj	o
time	nn	o
,	,	o
a	dt	o
run-time	jj	o
panic	nn	o
occurs	nns	o
.	.	o
Type	nnp	b-person
assertions	nns	o
For	in	o
an	dt	o
expression	nn	o
of	in	o
interface	nn	o
type	nn	o
,	,	o
but	cc	o
not	rb	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
and	cc	o
a	dt	o
type	nn	o
,	,	o
the	dt	o
primary	jj	o
expression	nn	o
asserts	vbz	o
that	wdt	o
is	vbz	o
not	rb	o
and	cc	o
that	wdt	o
the	dt	o
value	nn	o
stored	vbn	o
in	in	o
is	vbz	o
of	in	o
type	nn	o
.	.	o
The	dt	o
notation	nn	o
is	vbz	o
called	vbd	o
a	dt	o
type	nn	o
assertion	nn	o
.	.	o
More	rbr	o
precisely	rb	o
,	,	o
if	in	o
is	vbz	o
not	rb	o
an	dt	o
interface	nn	o
type	nn	o
,	,	o
asserts	vbz	o
that	wdt	o
the	dt	o
dynamic	jj	o
type	nn	o
of	in	o
is	vbz	o
identical	jj	o
to	to	o
the	dt	o
type	nn	o
.	.	o
In	in	o
this	dt	o
case	nn	o
,	,	o
must	md	o
implement	vb	o
the	dt	o
(	(	o
interface	nn	o
)	)	o
type	nn	o
of	in	o
;	:	o
otherwise	rb	o
the	dt	o
type	nn	o
assertion	nn	o
is	vbz	o
invalid	jj	o
since	in	o
it	prp	o
is	vbz	o
not	rb	o
possible	jj	o
for	in	o
to	to	o
store	vb	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
.	.	o
If	in	o
is	vbz	o
an	dt	o
interface	nn	o
type	nn	o
,	,	o
asserts	vbz	o
that	wdt	o
the	dt	o
dynamic	jj	o
type	nn	o
of	in	o
implements	vbz	o
the	dt	o
interface	nn	o
.	.	o
If	in	o
the	dt	o
type	nn	o
assertion	nn	o
holds	vbz	o
,	,	o
the	dt	o
value	nn	o
of	in	o
the	dt	o
expression	nn	o
is	vbz	o
the	dt	o
value	nn	o
stored	vbn	o
in	in	o
and	cc	o
its	prp$	o
type	nn	o
is	vbz	o
.	.	o
If	in	o
the	dt	o
type	nn	o
assertion	nn	o
is	vbz	o
false	jj	o
,	,	o
a	dt	o
run-time	jj	o
panic	nn	o
occurs	nns	o
.	.	o
In	in	o
other	jj	o
words	nns	o
,	,	o
even	rb	o
though	in	o
the	dt	o
dynamic	jj	o
type	nn	o
of	in	o
is	vbz	o
known	vbn	o
only	rb	o
at	in	o
run	jj	o
time	nn	o
,	,	o
the	dt	o
type	nn	o
of	in	o
is	vbz	o
known	vbn	o
to	to	o
be	vb	o
in	in	o
a	dt	o
correct	jj	o
program	nn	o
.	.	o
A	dt	o
type	nn	o
assertion	nn	o
used	vbn	o
in	in	o
an	dt	o
assignment	nn	o
or	cc	o
initialization	nn	o
of	in	o
the	dt	o
special	jj	o
form	nn	o
yields	nns	o
an	dt	o
additional	jj	o
untyped	jj	o
boolean	jj	o
value	nn	o
.	.	o
The	dt	o
value	nn	o
of	in	o
is	vbz	o
if	in	o
the	dt	o
assertion	nn	o
holds	vbz	o
.	.	o
Otherwise	vb	o
it	prp	o
is	vbz	o
and	cc	o
the	dt	o
value	nn	o
of	in	o
is	vbz	o
the	dt	o
zero	nn	o
value	nn	o
for	in	o
type	nn	o
.	.	o
No	dt	o
run-time	jj	o
panic	nn	o
occurs	nn	o
in	in	o
this	dt	o
case	nn	o
.	.	o
Calls	vbz	o
Given	vbn	o
an	dt	o
expression	nn	o
with	in	o
a	dt	o
core	nn	o
type	nn	o
of	in	o
function	nn	o
type	nn	o
,	,	o
calls	vbz	o
with	in	o
arguments	nns	o
.	.	o
Except	in	o
for	in	o
one	nn	o
special	jj	o
case	nn	o
,	,	o
arguments	nns	o
must	md	o
be	vb	o
single-valued	jj	o
expressions	nns	o
assignable	jj	o
to	to	o
the	dt	o
parameter	nn	o
types	nns	o
of	in	o
and	cc	o
are	vbp	o
evaluated	vbn	o
before	in	o
the	dt	o
function	nn	o
is	vbz	o
called	vbn	o
.	.	o
The	dt	o
type	nn	o
of	in	o
the	dt	o
expression	nn	o
is	vbz	o
the	dt	o
result	nn	o
type	nn	o
of	in	o
.	.	o
A	dt	o
method	nn	o
invocation	nn	o
is	vbz	o
similar	jj	o
but	cc	o
the	dt	o
method	nn	o
itself	prp	o
is	vbz	o
specified	vbn	o
as	in	o
a	dt	o
selector	nn	o
upon	in	o
a	dt	o
value	nn	o
of	in	o
the	dt	o
receiver	nn	o
type	nn	o
for	in	o
the	dt	o
method	nn	o
.	.	o
If	in	o
denotes	vbz	o
a	dt	o
generic	jj	o
function	nn	o
,	,	o
it	prp	o
must	md	o
be	vb	o
instantiated	vbn	o
before	in	o
it	prp	o
can	md	o
be	vb	o
called	vbd	o
or	cc	o
used	vbn	o
as	in	o
a	dt	o
function	nn	o
value	nn	o
.	.	o
In	in	o
a	dt	o
function	nn	o
call	nn	o
,	,	o
the	dt	o
function	nn	o
value	nn	o
and	cc	o
arguments	nns	o
are	vbp	o
evaluated	vbn	o
in	in	o
the	dt	o
usual	jj	o
order	nn	o
.	.	o
After	in	o
they	prp	o
are	vbp	o
evaluated	vbn	o
,	,	o
the	dt	o
parameters	nns	o
of	in	o
the	dt	o
call	nn	o
are	vbp	o
passed	vbd	o
by	in	o
value	nn	o
to	to	o
the	dt	o
function	nn	o
and	cc	o
the	dt	o
called	vbd	o
function	nn	o
begins	vbz	o
execution	nn	o
.	.	o
The	dt	o
return	vb	o
parameters	nns	o
of	in	o
the	dt	o
function	nn	o
are	vbp	o
passed	vbd	o
by	in	o
value	nn	o
back	rb	o
to	to	o
the	dt	o
caller	nn	o
when	wrb	o
the	dt	o
function	nn	o
returns	nns	o
.	.	o
Calling	vbg	o
a	dt	o
function	nn	o
value	nn	o
causes	vbz	o
a	dt	o
run-time	jj	o
panic	nn	o
.	.	o
As	in	o
a	dt	o
special	jj	o
case	nn	o
,	,	o
if	in	o
the	dt	o
return	vb	o
values	nns	o
of	in	o
a	dt	o
function	nn	o
or	cc	o
method	nn	o
are	vbp	o
equal	vb	o
in	in	o
number	nn	o
and	cc	o
individually	rb	o
assignable	jj	o
to	to	o
the	dt	o
parameters	nns	o
of	in	o
another	dt	o
function	nn	o
or	cc	o
method	nn	o
,	,	o
then	rb	o
the	dt	o
call	nn	o
will	md	o
invoke	vb	o
after	in	o
binding	vbg	o
the	dt	o
return	vb	o
values	nns	o
of	in	o
to	to	o
the	dt	o
parameters	nns	o
of	in	o
in	in	o
order	nn	o
.	.	o
The	dt	o
call	nn	o
of	in	o
must	md	o
contain	vb	o
no	dt	o
parameters	nns	o
other	jj	o
than	in	o
the	dt	o
call	nn	o
of	in	o
,	,	o
and	cc	o
must	md	o
have	vb	o
at	in	o
least	jjs	o
one	nn	o
return	vb	o
value	nn	o
.	.	o
If	in	o
has	vbz	o
a	dt	o
final	jj	o
parameter	nn	o
,	,	o
it	prp	o
is	vbz	o
assigned	vbn	o
the	dt	o
return	vb	o
values	nns	o
of	in	o
that	wdt	o
remain	vbp	o
after	in	o
assignment	nn	o
of	in	o
regular	jj	o
parameters	nns	o
.	.	o
A	dt	o
method	nn	o
call	nn	o
is	vbz	o
valid	jj	o
if	in	o
the	dt	o
method	nn	o
set	nn	o
of	in	o
(	(	o
the	dt	o
type	nn	o
of	in	o
)	)	o
contains	vbz	o
and	cc	o
the	dt	o
argument	nn	o
list	nn	o
can	md	o
be	vb	o
assigned	vbn	o
to	to	o
the	dt	o
parameter	nn	o
list	nn	o
of	in	o
.	.	o
If	in	o
is	vbz	o
addressable	jj	o
and	cc	o
's	pos	o
method	nn	o
set	nn	o
contains	vbz	o
,	,	o
is	vbz	o
shorthand	nn	o
for	in	o
:	:	o
There	ex	o
is	vbz	o
no	dt	o
distinct	jj	o
method	nn	o
type	nn	o
and	cc	o
there	ex	o
are	vbp	o
no	dt	o
method	nn	o
literals	nns	o
.	.	o
Passing	vbg	o
arguments	nns	o
to	to	o
parameters	nns	o
If	in	o
is	vbz	o
variadic	jj	o
with	in	o
a	dt	o
final	jj	o
parameter	nn	o
of	in	o
type	nn	o
,	,	o
then	rb	o
within	in	o
the	dt	o
type	nn	o
of	in	o
is	vbz	o
equivalent	jj	o
to	to	o
type	nn	o
.	.	o
If	in	o
is	vbz	o
invoked	vbn	o
with	in	o
no	dt	o
actual	jj	o
arguments	nns	o
for	in	o
,	,	o
the	dt	o
value	nn	o
passed	vbd	o
to	to	o
is	vbz	o
.	.	o
Otherwise	rb	o
,	,	o
the	dt	o
value	nn	o
passed	vbd	o
is	vbz	o
a	dt	o
new	jj	o
slice	nn	o
of	in	o
type	nn	o
with	in	o
a	dt	o
new	jj	o
underlying	jj	o
array	nn	o
whose	wp$	o
successive	jj	o
elements	nns	o
are	vbp	o
the	dt	o
actual	jj	o
arguments	nns	o
,	,	o
which	wdt	o
all	pdt	o
must	md	o
be	vb	o
assignable	jj	o
to	to	o
.	.	o
The	dt	o
length	nn	o
and	cc	o
capacity	nn	o
of	in	o
the	dt	o
slice	nn	o
is	vbz	o
therefore	rb	o
the	dt	o
number	nn	o
of	in	o
arguments	nns	o
bound	vbn	o
to	to	o
and	cc	o
may	md	o
differ	vb	o
for	in	o
each	dt	o
call	nn	o
site	nn	o
.	.	o
Given	vbn	o
the	dt	o
function	nn	o
and	cc	o
calls	vbz	o
within	in	o
,	,	o
will	md	o
have	vb	o
the	dt	o
value	nn	o
in	in	o
the	dt	o
first	jj	o
call	nn	o
,	,	o
and	cc	o
in	in	o
the	dt	o
second	jj	o
.	.	o
If	in	o
the	dt	o
final	jj	o
argument	nn	o
is	vbz	o
assignable	jj	o
to	to	o
a	dt	o
slice	nn	o
type	nn	o
and	cc	o
is	vbz	o
followed	vbn	o
by	in	o
,	,	o
it	prp	o
is	vbz	o
passed	vbd	o
unchanged	jj	o
as	in	o
the	dt	o
value	nn	o
for	in	o
a	dt	o
parameter	nn	o
.	.	o
In	in	o
this	dt	o
case	nn	o
no	dt	o
new	jj	o
slice	nn	o
is	vbz	o
created	vbn	o
.	.	o
Given	vbn	o
the	dt	o
slice	nn	o
and	cc	o
call	nn	o
within	in	o
,	,	o
will	md	o
have	vb	o
the	dt	o
same	jj	o
value	nn	o
as	in	o
with	in	o
the	dt	o
same	jj	o
underlying	jj	o
array	nn	o
.	.	o
Instantiations	vbz	o
A	dt	o
generic	jj	o
function	nn	o
or	cc	o
type	nn	o
is	vbz	o
instantiated	vbn	o
by	in	o
substituting	vbg	o
type	nn	o
arguments	nns	o
for	in	o
the	dt	o
type	nn	o
parameters	nns	o
.	.	o
Instantiation	nnp	o
proceeds	nns	o
in	in	o
two	cd	o
phases	nns	o
:	:	o
Each	dt	o
type	nn	o
argument	nn	o
is	vbz	o
substituted	vbn	o
for	in	o
its	prp$	o
corresponding	jj	o
type	nn	o
parameter	nn	o
in	in	o
the	dt	o
generic	jj	o
declaration	nn	o
.	.	o
This	dt	o
substitution	nn	o
happens	vbz	o
across	in	o
the	dt	o
entire	jj	o
function	nn	o
or	cc	o
type	nn	o
declaration	nn	o
,	,	o
including	vbg	o
the	dt	o
type	nn	o
parameter	nn	o
list	nn	o
itself	prp	o
and	cc	o
any	dt	o
types	nns	o
in	in	o
that	wdt	o
list	nn	o
.	.	o
After	in	o
substitution	nn	o
,	,	o
each	dt	o
type	nn	o
argument	nn	o
must	md	o
implement	vb	o
the	dt	o
constraint	nn	o
(	(	o
instantiated	vbn	o
,	,	o
if	in	o
necessary	jj	o
)	)	o
of	in	o
the	dt	o
corresponding	jj	o
type	nn	o
parameter	nn	o
.	.	o
Otherwise	vb	o
instantiation	nn	o
fails	vbz	o
.	.	o
Instantiating	vbg	o
a	dt	o
type	nn	o
results	nns	o
in	in	o
a	dt	o
new	jj	o
non-generic	jj	o
named	vbn	o
type	nn	o
;	:	o
instantiating	vbg	o
a	dt	o
function	nn	o
produces	vbz	o
a	dt	o
new	jj	o
non-generic	jj	o
function	nn	o
.	.	o
Type	nnp	b-person
arguments	nns	o
may	md	o
be	vb	o
provided	vbn	o
explicitly	rb	o
,	,	o
or	cc	o
they	prp	o
may	md	o
be	vb	o
partially	rb	o
or	cc	o
completely	rb	o
inferred	vbn	o
.	.	o
A	dt	o
partially	rb	o
provided	vbn	o
type	nn	o
argument	nn	o
list	nn	o
cannot	vbp	o
be	vb	o
empty	jj	o
;	:	o
there	ex	o
must	md	o
be	vb	o
at	in	o
least	jjs	o
the	dt	o
first	jj	o
argument	nn	o
.	.	o
A	dt	o
partial	jj	o
type	nn	o
argument	nn	o
list	nn	o
specifies	vbz	o
a	dt	o
prefix	nn	o
of	in	o
the	dt	o
full	jj	o
list	nn	o
of	in	o
type	nn	o
arguments	nns	o
,	,	o
leaving	vbg	o
the	dt	o
remaining	vbg	o
arguments	nns	o
to	to	o
be	vb	o
inferred	vbn	o
.	.	o
Loosely	rb	o
speaking	vbg	o
,	,	o
type	nn	o
arguments	nns	o
may	md	o
be	vb	o
omitted	vbn	o
from	in	o
"	rb	o
right	jj	o
to	to	o
left	vb	o
"	nnp	o
.	.	o
Generic	nnp	o
types	nns	o
,	,	o
and	cc	o
generic	jj	o
functions	nns	o
that	wdt	o
are	vbp	o
not	rb	o
called	vbn	o
,	,	o
require	vb	o
a	dt	o
type	nn	o
argument	nn	o
list	nn	o
for	in	o
instantiation	nn	o
;	:	o
if	in	o
the	dt	o
list	nn	o
is	vbz	o
partial	jj	o
,	,	o
all	pdt	o
remaining	vbg	o
type	nn	o
arguments	nns	o
must	md	o
be	vb	o
inferrable	jj	o
.	.	o
Calls	vbz	o
to	to	o
generic	jj	o
functions	nns	o
may	md	o
provide	vbp	o
a	dt	o
(	(	o
possibly	rb	o
partial	nn	o
)	)	o
type	nn	o
argument	nn	o
list	nn	o
,	,	o
or	cc	o
may	md	o
omit	vb	o
it	prp	o
entirely	rb	o
if	in	o
the	dt	o
omitted	vbn	o
type	nn	o
arguments	nns	o
are	vbp	o
inferrable	jj	o
from	in	o
the	dt	o
ordinary	jj	o
(	(	o
non-type	jj	o
)	)	o
function	nn	o
arguments	nns	o
.	.	o
Type	nnp	b-person
inference	nn	o
Missing	vbg	o
type	nn	o
arguments	nns	o
may	md	o
be	vb	o
inferred	jj	o
by	in	o
a	dt	o
series	nn	o
of	in	o
steps	nns	o
,	,	o
described	vbn	o
below	in	o
.	.	o
Each	dt	o
step	nn	o
attempts	nns	o
to	to	o
use	vbp	o
known	vbn	o
information	nn	o
to	to	o
infer	vb	o
additional	jj	o
type	nn	o
arguments	nns	o
.	.	o
Type	nnp	b-person
inference	nn	o
stops	vbz	o
as	in	o
soon	rb	o
as	in	o
all	pdt	o
type	nn	o
arguments	nns	o
are	vbp	o
known	vbn	o
.	.	o
After	in	o
type	nn	o
inference	nn	o
is	vbz	o
complete	jj	o
,	,	o
it	prp	o
is	vbz	o
still	rb	o
necessary	jj	o
to	to	o
substitute	vbp	o
all	pdt	o
type	nn	o
arguments	nns	o
for	in	o
type	nn	o
parameters	nns	o
and	cc	o
verify	vb	o
that	wdt	o
each	dt	o
type	nn	o
argument	nn	o
implements	vbz	o
the	dt	o
relevant	jj	o
constraint	nn	o
;	:	o
it	prp	o
is	vbz	o
possible	jj	o
for	in	o
an	dt	o
inferred	jj	o
type	nn	o
argument	nn	o
to	to	o
fail	vb	o
to	to	o
implement	vb	o
a	dt	o
constraint	nn	o
,	,	o
in	in	o
which	wdt	o
case	nn	o
instantiation	nn	o
fails	vbz	o
.	.	o
Type	nnp	b-person
inference	nn	o
is	vbz	o
based	vbn	o
on	in	o
a	dt	o
type	nn	o
parameter	nn	o
list	nn	o
a	dt	o
substitution	nn	o
map	nn	o
M	nnp	o
initialized	vbn	o
with	in	o
the	dt	o
known	vbn	o
type	nn	o
arguments	nns	o
,	,	o
if	in	o
any	dt	o
a	dt	o
(	(	o
possibly	rb	o
empty	rb	o
)	)	o
list	nn	o
of	in	o
ordinary	jj	o
function	nn	o
arguments	nns	o
(	(	o
in	in	o
case	nn	o
of	in	o
a	dt	o
function	nn	o
call	nn	o
only	rb	o
)	)	o
and	cc	o
then	rb	o
proceeds	nns	o
with	in	o
the	dt	o
following	vbg	o
steps	nns	o
:	:	o
apply	vbp	o
function	nn	o
argument	nn	o
type	nn	o
inference	nn	o
to	to	o
all	pdt	o
typed	jj	o
ordinary	jj	o
function	nn	o
arguments	nns	o
apply	vbp	o
constraint	nn	o
type	nn	o
inference	nn	o
apply	vbp	o
function	nn	o
argument	nn	o
type	nn	o
inference	nn	o
to	to	o
all	pdt	o
untyped	jj	o
ordinary	jj	o
function	nn	o
arguments	nns	o
using	vbg	o
the	dt	o
default	nn	o
type	nn	o
for	in	o
each	dt	o
of	in	o
the	dt	o
untyped	jj	o
function	nn	o
arguments	nns	o
apply	vbp	o
constraint	nn	o
type	nn	o
inference	nn	o
If	in	o
there	ex	o
are	vbp	o
no	dt	o
ordinary	jj	o
or	cc	o
untyped	jj	o
function	nn	o
arguments	nns	o
,	,	o
the	dt	o
respective	jj	o
steps	nns	o
are	vbp	o
skipped	vbn	o
.	.	o
Constraint	nnp	o
type	nn	o
inference	nn	o
is	vbz	o
skipped	vbn	o
if	in	o
the	dt	o
previous	jj	o
step	nn	o
did	vbd	o
n't	rb	o
infer	vb	o
any	dt	o
new	jj	o
type	nn	o
arguments	nns	o
,	,	o
but	cc	o
it	prp	o
is	vbz	o
run	jj	o
at	in	o
least	jjs	o
once	rb	o
if	in	o
there	ex	o
are	vbp	o
missing	jj	o
type	nn	o
arguments	nns	o
.	.	o
The	dt	o
substitution	nn	o
map	nn	o
M	nnp	o
is	vbz	o
carried	vbn	o
through	in	o
all	pdt	o
steps	nns	o
,	,	o
and	cc	o
each	dt	o
step	nn	o
may	md	o
add	vb	o
entries	nns	o
to	to	o
M	nnp	o
.	.	o
The	dt	o
process	nn	o
stops	vbz	o
as	in	o
soon	rb	o
as	in	o
M	nnp	o
has	vbz	o
a	dt	o
type	nn	o
argument	nn	o
for	in	o
each	dt	o
type	nn	o
parameter	nn	o
or	cc	o
if	in	o
an	dt	o
inference	nn	o
step	nn	o
fails	vbz	o
.	.	o
If	in	o
an	dt	o
inference	nn	o
step	nn	o
fails	vbz	o
,	,	o
or	cc	o
if	in	o
M	nnp	o
is	vbz	o
still	rb	o
missing	jj	o
type	nn	o
arguments	nns	o
after	in	o
the	dt	o
last	jj	o
step	nn	o
,	,	o
type	nn	o
inference	nn	o
fails	vbz	o
.	.	o
Type	nnp	b-person
unification	nn	o
Type	nnp	b-person
inference	nn	o
is	vbz	o
based	vbn	o
on	in	o
type	nn	o
unification	nn	o
.	.	o
A	dt	o
single	jj	o
unification	nn	o
step	nn	o
applies	nns	o
to	to	o
a	dt	o
substitution	nn	o
map	nn	o
and	cc	o
two	cd	o
types	nns	o
,	,	o
either	dt	o
or	cc	o
both	dt	o
of	in	o
which	wdt	o
may	md	o
be	vb	o
or	cc	o
contain	vb	o
type	nn	o
parameters	nns	o
.	.	o
The	dt	o
substitution	nn	o
map	nn	o
tracks	vbz	o
the	dt	o
known	vbn	o
(	(	o
explicitly	rb	o
provided	vbn	o
or	cc	o
already	rb	o
inferred	vbn	o
)	)	o
type	nn	o
arguments	nns	o
:	:	o
the	dt	o
map	nn	o
contains	vbz	o
an	dt	o
entry	nn	o
→	nn	o
for	in	o
each	dt	o
type	nn	o
parameter	nn	o
and	cc	o
corresponding	jj	o
known	vbn	o
type	nn	o
argument	nn	o
.	.	o
During	in	o
unification	nn	o
,	,	o
known	vbn	o
type	nn	o
arguments	nns	o
take	vb	o
the	dt	o
place	nn	o
of	in	o
their	prp$	o
corresponding	jj	o
type	nn	o
parameters	nns	o
when	wrb	o
comparing	vbg	o
types	nns	o
.	.	o
Unification	nn	o
is	vbz	o
the	dt	o
process	nn	o
of	in	o
finding	vbg	o
substitution	nn	o
map	nn	o
entries	nns	o
that	wdt	o
make	vbp	o
the	dt	o
two	cd	o
types	nns	o
equivalent	jj	o
.	.	o
For	in	o
unification	nn	o
,	,	o
two	cd	o
types	nns	o
that	wdt	o
do	vbp	o
n't	rb	o
contain	vb	o
any	dt	o
type	nn	o
parameters	nns	o
from	in	o
the	dt	o
current	jj	o
type	nn	o
parameter	nn	o
list	nn	o
are	vbp	o
equivalent	jj	o
if	in	o
they	prp	o
are	vbp	o
identical	jj	o
,	,	o
or	cc	o
if	in	o
they	prp	o
are	vbp	o
channel	nns	o
types	nns	o
that	wdt	o
are	vbp	o
identical	jj	o
ignoring	vbg	o
channel	nns	o
direction	nn	o
,	,	o
or	cc	o
if	in	o
their	prp$	o
underlying	jj	o
types	nns	o
are	vbp	o
equivalent	jj	o
.	.	o
Unification	nn	o
works	nns	o
by	in	o
comparing	vbg	o
the	dt	o
structure	nn	o
of	in	o
pairs	nns	o
of	in	o
types	nns	o
:	:	o
their	prp$	o
structure	nn	o
disregarding	vbg	o
type	nn	o
parameters	nns	o
must	md	o
be	vb	o
identical	jj	o
,	,	o
and	cc	o
types	nns	o
other	jj	o
than	in	o
type	nn	o
parameters	nns	o
must	md	o
be	vb	o
equivalent	jj	o
.	.	o
A	dt	o
type	nn	o
parameter	nn	o
in	in	o
one	nn	o
type	nn	o
may	md	o
match	vbp	o
any	dt	o
complete	jj	o
subtype	nn	o
in	in	o
the	dt	o
other	jj	o
type	nn	o
;	:	o
each	dt	o
successful	jj	o
match	vbp	o
causes	vbz	o
an	dt	o
entry	nn	o
to	to	o
be	vb	o
added	vbn	o
to	to	o
the	dt	o
substitution	nn	o
map	nn	o
.	.	o
If	in	o
the	dt	o
structure	nn	o
differs	nns	o
,	,	o
or	cc	o
types	nns	o
other	jj	o
than	in	o
type	nn	o
parameters	nns	o
are	vbp	o
not	rb	o
equivalent	jj	o
,	,	o
unification	nn	o
fails	vbz	o
.	.	o
For	in	o
example	nn	o
,	,	o
if	in	o
and	cc	o
are	vbp	o
type	nn	o
parameters	nns	o
,	,	o
can	md	o
be	vb	o
unified	vbn	o
with	in	o
any	dt	o
of	in	o
the	dt	o
following	nn	o
:	:	o
On	in	o
the	dt	o
other	jj	o
hand	nn	o
,	,	o
cannot	vbp	o
be	vb	o
unified	vbn	o
with	in	o
any	dt	o
of	in	o
As	in	o
an	dt	o
exception	nn	o
to	to	o
this	dt	o
general	jj	o
rule	nn	o
,	,	o
because	in	o
a	dt	o
defined	vbn	o
type	nn	o
and	cc	o
a	dt	o
type	nn	o
literal	nn	o
are	vbp	o
never	rb	o
equivalent	jj	o
,	,	o
unification	nn	o
compares	vbz	o
the	dt	o
underlying	jj	o
type	nn	o
of	in	o
with	in	o
instead	rb	o
.	.	o
For	in	o
example	nn	o
,	,	o
given	vbn	o
the	dt	o
defined	vbn	o
type	nn	o
and	cc	o
the	dt	o
type	nn	o
literal	nn	o
,	,	o
unification	nn	o
compares	vbz	o
with	in	o
and	cc	o
adds	vbz	o
an	dt	o
entry	nn	o
→	nn	o
to	to	o
the	dt	o
substitution	nn	o
map	nn	o
.	.	o
Function	nnp	b-person
argument	nn	o
type	nn	o
inference	nn	o
Function	nnp	b-person
argument	nn	o
type	nn	o
inference	nn	o
infers	nns	o
type	nn	o
arguments	nns	o
from	in	o
function	nn	o
arguments	nns	o
:	:	o
if	in	o
a	dt	o
function	nn	o
parameter	nn	o
is	vbz	o
declared	vbn	o
with	in	o
a	dt	o
type	nn	o
that	wdt	o
uses	nns	o
type	nn	o
parameters	nns	o
,	,	o
unifying	jj	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
corresponding	jj	o
function	nn	o
argument	nn	o
with	in	o
may	md	o
infer	vb	o
type	nn	o
arguments	nns	o
for	in	o
the	dt	o
type	nn	o
parameters	nns	o
used	vbn	o
by	in	o
.	.	o
For	in	o
instance	nn	o
,	,	o
given	vbn	o
the	dt	o
generic	jj	o
function	nn	o
and	cc	o
the	dt	o
call	nn	o
the	dt	o
type	nn	o
argument	nn	o
for	in	o
can	md	o
be	vb	o
inferred	jj	o
from	in	o
the	dt	o
function	nn	o
argument	nn	o
by	in	o
unifying	jj	o
the	dt	o
type	nn	o
of	in	o
with	in	o
the	dt	o
corresponding	jj	o
parameter	nn	o
type	nn	o
:	:	o
and	cc	o
match	vbp	o
in	in	o
structure	nn	o
and	cc	o
matches	nns	o
with	in	o
.	.	o
This	dt	o
adds	vbz	o
the	dt	o
entry	nn	o
→	nn	o
to	to	o
the	dt	o
substitution	nn	o
map	nn	o
.	.	o
Untyped	jj	o
arguments	nns	o
,	,	o
such	jj	o
as	in	o
the	dt	o
second	jj	o
function	nn	o
argument	nn	o
here	rb	o
,	,	o
are	vbp	o
ignored	vbn	o
in	in	o
the	dt	o
first	jj	o
round	nn	o
of	in	o
function	nn	o
argument	nn	o
type	nn	o
inference	nn	o
and	cc	o
only	rb	o
considered	vbn	o
if	in	o
there	ex	o
are	vbp	o
unresolved	jj	o
type	nn	o
parameters	nns	o
left	vbd	o
.	.	o
Function	nnp	b-person
argument	nn	o
type	nn	o
inference	nn	o
can	md	o
be	vb	o
used	vbn	o
when	wrb	o
the	dt	o
function	nn	o
has	vbz	o
ordinary	jj	o
parameters	nns	o
whose	wp$	o
types	nns	o
are	vbp	o
defined	vbn	o
using	vbg	o
the	dt	o
function	nn	o
's	pos	o
type	nn	o
parameters	nns	o
.	.	o
Inference	nn	o
happens	vbz	o
in	in	o
two	cd	o
separate	jj	o
phases	nns	o
;	:	o
each	dt	o
phase	nn	o
operates	vbz	o
on	in	o
a	dt	o
specific	jj	o
list	nn	o
of	in	o
(	(	o
parameter	nn	o
,	,	o
argument	nn	o
)	)	o
pairs	nn	o
:	:	o
The	dt	o
list	nn	o
Lt	nnp	b-gpe
contains	vbz	o
all	pdt	o
(	(	o
parameter	nn	o
,	,	o
argument	nn	o
)	)	o
pairs	nns	o
where	wrb	o
the	dt	o
parameter	nn	o
type	nn	o
uses	nns	o
type	nn	o
parameters	nns	o
and	cc	o
where	wrb	o
the	dt	o
function	nn	o
argument	nn	o
is	vbz	o
typed	vbn	o
.	.	o
The	dt	o
list	nn	o
Lu	nnp	b-gpe
contains	vbz	o
all	pdt	o
remaining	vbg	o
pairs	nns	o
where	wrb	o
the	dt	o
parameter	nn	o
type	nn	o
is	vbz	o
a	dt	o
single	jj	o
type	nn	o
parameter	nn	o
.	.	o
In	in	o
this	dt	o
list	nn	o
,	,	o
the	dt	o
respective	jj	o
function	nn	o
arguments	nns	o
are	vbp	o
untyped	jj	o
.	.	o
Any	dt	o
other	jj	o
(	(	o
parameter	nn	o
,	,	o
argument	nn	o
)	)	o
pair	nn	o
is	vbz	o
ignored	vbn	o
.	.	o
By	in	o
construction	nn	o
,	,	o
the	dt	o
arguments	nns	o
of	in	o
the	dt	o
pairs	nns	o
in	in	o
Lu	nnp	b-gpe
are	vbp	o
untyped	jj	o
constants	nns	o
(	(	o
or	cc	o
the	dt	o
untyped	jj	o
boolean	jj	o
result	nn	o
of	in	o
a	dt	o
comparison	nn	o
)	)	o
.	.	o
And	cc	o
because	in	o
default	nn	o
types	nns	o
of	in	o
untyped	jj	o
values	nns	o
are	vbp	o
always	rb	o
predeclared	jj	o
non-composite	jj	o
types	nns	o
,	,	o
they	prp	o
can	md	o
never	rb	o
match	vbp	o
against	in	o
a	dt	o
composite	jj	o
type	nn	o
,	,	o
so	rb	o
it	prp	o
is	vbz	o
sufficient	jj	o
to	to	o
only	rb	o
consider	vb	o
parameter	nn	o
types	nns	o
that	wdt	o
are	vbp	o
single	jj	o
type	nn	o
parameters	nns	o
.	.	o
Each	dt	o
list	nn	o
is	vbz	o
processed	vbn	o
in	in	o
a	dt	o
separate	jj	o
phase	nn	o
:	:	o
In	in	o
the	dt	o
first	jj	o
phase	nn	o
,	,	o
the	dt	o
parameter	nn	o
and	cc	o
argument	nn	o
types	nns	o
of	in	o
each	dt	o
pair	nn	o
in	in	o
Lt	nnp	b-gpe
are	vbp	o
unified	vbn	o
.	.	o
If	in	o
unification	nn	o
succeeds	vbz	o
for	in	o
a	dt	o
pair	nn	o
,	,	o
it	prp	o
may	md	o
yield	vb	o
new	jj	o
entries	nns	o
that	wdt	o
are	vbp	o
added	vbn	o
to	to	o
the	dt	o
substitution	nn	o
map	nn	o
M	nnp	o
.	.	o
If	in	o
unification	nn	o
fails	vbz	o
,	,	o
type	nn	o
inference	nn	o
fails	vbz	o
.	.	o
The	dt	o
second	jj	o
phase	nn	o
considers	vbz	o
the	dt	o
entries	nns	o
of	in	o
list	nn	o
Lu.	nnp	o
Type	nnp	b-person
parameters	nns	o
for	in	o
which	wdt	o
the	dt	o
type	nn	o
argument	nn	o
has	vbz	o
already	rb	o
been	vbn	o
determined	vbn	o
are	vbp	o
ignored	vbn	o
in	in	o
this	dt	o
phase	nn	o
.	.	o
For	in	o
each	dt	o
remaining	vbg	o
pair	nn	o
,	,	o
the	dt	o
parameter	nn	o
type	nn	o
(	(	o
which	wdt	o
is	vbz	o
a	dt	o
single	jj	o
type	nn	o
parameter	nn	o
)	)	o
and	cc	o
the	dt	o
default	nn	o
type	nn	o
of	in	o
the	dt	o
corresponding	jj	o
untyped	jj	o
argument	nn	o
is	vbz	o
unified	vbn	o
.	.	o
If	in	o
unification	nn	o
fails	vbz	o
,	,	o
type	nn	o
inference	nn	o
fails	vbz	o
.	.	o
While	in	o
unification	nn	o
is	vbz	o
successful	jj	o
,	,	o
processing	vbg	o
of	in	o
each	dt	o
list	nn	o
continues	vbz	o
until	in	o
all	pdt	o
list	nn	o
elements	nns	o
are	vbp	o
considered	vbn	o
,	,	o
even	rb	o
if	in	o
all	pdt	o
type	nn	o
arguments	nns	o
are	vbp	o
inferred	jj	o
before	in	o
the	dt	o
last	jj	o
list	nn	o
element	nn	o
has	vbz	o
been	vbn	o
processed	vbn	o
.	.	o
Example	nn	o
:	:	o
In	in	o
the	dt	o
example	nn	o
,	,	o
processing	vbg	o
the	dt	o
function	nn	o
argument	nn	o
yields	nns	o
the	dt	o
substitution	nn	o
map	nn	o
entry	nn	o
→	nn	o
.	.	o
Because	in	o
processing	vbg	o
continues	vbz	o
until	in	o
all	pdt	o
untyped	jj	o
arguments	nns	o
are	vbp	o
considered	vbn	o
,	,	o
an	dt	o
error	nn	o
is	vbz	o
reported	vbn	o
.	.	o
This	dt	o
ensures	vbz	o
that	wdt	o
type	nn	o
inference	nn	o
does	vbz	o
not	rb	o
depend	vb	o
on	in	o
the	dt	o
order	nn	o
of	in	o
the	dt	o
untyped	jj	o
arguments	nns	o
.	.	o
Constraint	nnp	o
type	nn	o
inference	nn	o
Constraint	nnp	o
type	nn	o
inference	nn	o
infers	nns	o
type	nn	o
arguments	nns	o
by	in	o
considering	vbg	o
type	nn	o
constraints	nns	o
.	.	o
If	in	o
a	dt	o
type	nn	o
parameter	nn	o
has	vbz	o
a	dt	o
constraint	nn	o
with	in	o
a	dt	o
core	nn	o
type	nn	o
,	,	o
unifying	jj	o
with	in	o
may	md	o
infer	vb	o
additional	jj	o
type	nn	o
arguments	nns	o
,	,	o
either	dt	o
the	dt	o
type	nn	o
argument	nn	o
for	in	o
,	,	o
or	cc	o
if	in	o
that	wdt	o
is	vbz	o
already	rb	o
known	vbn	o
,	,	o
possibly	rb	o
the	dt	o
type	nn	o
arguments	nns	o
for	in	o
type	nn	o
parameters	nns	o
used	vbn	o
in	in	o
.	.	o
For	in	o
instance	nn	o
,	,	o
consider	vb	o
the	dt	o
type	nn	o
parameter	nn	o
list	nn	o
with	in	o
type	nn	o
parameters	nns	o
and	cc	o
:	:	o
Constraint	nnp	o
type	nn	o
inference	nn	o
can	md	o
deduce	vb	o
the	dt	o
type	nn	o
of	in	o
from	in	o
the	dt	o
type	nn	o
argument	nn	o
for	in	o
because	in	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
in	in	o
the	dt	o
core	nn	o
type	nn	o
of	in	o
.	.	o
If	in	o
the	dt	o
type	nn	o
argument	nn	o
is	vbz	o
:	:	o
unifying	jj	o
the	dt	o
underlying	jj	o
type	nn	o
of	in	o
with	in	o
the	dt	o
core	nn	o
type	nn	o
means	vbz	o
unifying	jj	o
with	in	o
.	.	o
That	dt	o
unification	nn	o
succeeds	vbz	o
and	cc	o
yields	nns	o
the	dt	o
substitution	nn	o
map	nn	o
entry	nn	o
→	nn	o
.	.	o
Thus	rb	o
,	,	o
in	in	o
this	dt	o
example	nn	o
,	,	o
constraint	nn	o
type	nn	o
inference	nn	o
can	md	o
infer	vb	o
the	dt	o
second	jj	o
type	nn	o
argument	nn	o
from	in	o
the	dt	o
first	jj	o
one	nn	o
.	.	o
Using	vbg	o
the	dt	o
core	nn	o
type	nn	o
of	in	o
a	dt	o
constraint	nn	o
may	md	o
lose	vb	o
some	dt	o
information	nn	o
:	:	o
In	in	o
the	dt	o
(	(	o
unlikely	jj	o
)	)	o
case	nn	o
that	wdt	o
the	dt	o
constraint	nn	o
's	pos	o
type	nn	o
set	nn	o
contains	vbz	o
a	dt	o
single	jj	o
defined	vbn	o
type	nn	o
,	,	o
the	dt	o
corresponding	jj	o
core	nn	o
type	nn	o
is	vbz	o
's	pos	o
underlying	jj	o
type	nn	o
rather	rb	o
than	in	o
itself	prp	o
.	.	o
In	in	o
this	dt	o
case	nn	o
,	,	o
constraint	nn	o
type	nn	o
inference	nn	o
may	md	o
succeed	vb	o
but	cc	o
instantiation	nn	o
will	md	o
fail	vb	o
because	in	o
the	dt	o
inferred	jj	o
type	nn	o
is	vbz	o
not	rb	o
in	in	o
the	dt	o
type	nn	o
set	nn	o
of	in	o
the	dt	o
constraint	nn	o
.	.	o
Thus	rb	o
,	,	o
constraint	nn	o
type	nn	o
inference	nn	o
uses	nns	o
the	dt	o
adjusted	vbn	o
core	nn	o
type	nn	o
of	in	o
a	dt	o
constraint	nn	o
:	:	o
if	in	o
the	dt	o
type	nn	o
set	nn	o
contains	vbz	o
a	dt	o
single	jj	o
type	nn	o
,	,	o
use	vbp	o
that	wdt	o
type	nn	o
;	:	o
otherwise	rb	o
use	vbp	o
the	dt	o
constraint	nn	o
's	pos	o
core	nn	o
type	nn	o
.	.	o
Generally	nnp	o
,	,	o
constraint	nn	o
type	nn	o
inference	nn	o
proceeds	nns	o
in	in	o
two	cd	o
phases	nns	o
:	:	o
Starting	vbg	o
with	in	o
a	dt	o
given	vbn	o
substitution	nn	o
map	nn	o
M	nnp	o
For	in	o
all	pdt	o
type	nn	o
parameters	nns	o
with	in	o
an	dt	o
adjusted	vbn	o
core	nn	o
type	nn	o
,	,	o
unify	vb	o
the	dt	o
type	nn	o
parameter	nn	o
with	in	o
that	wdt	o
type	nn	o
.	.	o
If	in	o
any	dt	o
unification	nn	o
fails	vbz	o
,	,	o
constraint	nn	o
type	nn	o
inference	nn	o
fails	vbz	o
.	.	o
At	in	o
this	dt	o
point	nn	o
,	,	o
some	dt	o
entries	nns	o
in	in	o
M	nnp	o
may	md	o
map	nn	o
type	nn	o
parameters	nns	o
to	to	o
other	jj	o
type	nn	o
parameters	nns	o
or	cc	o
to	to	o
types	nns	o
containing	vbg	o
type	nn	o
parameters	nns	o
.	.	o
For	in	o
each	dt	o
entry	nn	o
→	nn	o
in	in	o
M	nnp	o
where	wrb	o
is	vbz	o
or	cc	o
contains	vbz	o
type	nn	o
parameters	nns	o
for	in	o
which	wdt	o
there	ex	o
exist	vbp	o
entries	nns	o
→	nn	o
in	in	o
M	nnp	b-gpe
,	,	o
substitute	vbp	o
those	dt	o
with	in	o
the	dt	o
respective	jj	o
in	in	o
.	.	o
Stop	vb	o
when	wrb	o
no	dt	o
further	jj	o
substitution	nn	o
is	vbz	o
possible	jj	o
.	.	o
The	dt	o
result	nn	o
of	in	o
constraint	nn	o
type	nn	o
inference	nn	o
is	vbz	o
the	dt	o
final	jj	o
substitution	nn	o
map	nn	o
M	nnp	o
from	in	o
type	nn	o
parameters	nns	o
to	to	o
type	nn	o
arguments	nns	o
where	wrb	o
no	dt	o
type	nn	o
parameter	nn	o
appears	vbz	o
in	in	o
any	dt	o
of	in	o
the	dt	o
.	.	o
For	in	o
instance	nn	o
,	,	o
given	vbn	o
the	dt	o
type	nn	o
parameter	nn	o
list	nn	o
and	cc	o
the	dt	o
single	jj	o
provided	vbn	o
type	nn	o
argument	nn	o
for	in	o
type	nn	o
parameter	nn	o
,	,	o
the	dt	o
initial	jj	o
substitution	nn	o
map	nn	o
M	nnp	o
contains	vbz	o
the	dt	o
entry	nn	o
→	nn	o
.	.	o
In	in	o
the	dt	o
first	jj	o
phase	nn	o
,	,	o
the	dt	o
type	nn	o
parameters	nns	o
and	cc	o
are	vbp	o
unified	vbn	o
with	in	o
the	dt	o
core	nn	o
type	nn	o
of	in	o
their	prp$	o
respective	jj	o
constraints	nns	o
.	.	o
This	dt	o
adds	vbz	o
the	dt	o
entries	nns	o
→	nn	o
and	cc	o
→	nn	o
to	to	o
M	nnp	o
.	.	o
At	in	o
this	dt	o
point	nn	o
there	ex	o
are	vbp	o
two	cd	o
entries	nns	o
in	in	o
M	nnp	o
where	wrb	o
the	dt	o
right-hand	jj	o
side	nn	o
is	vbz	o
or	cc	o
contains	vbz	o
type	nn	o
parameters	nns	o
for	in	o
which	wdt	o
there	ex	o
exists	vbz	o
other	jj	o
entries	nns	o
in	in	o
M	nnp	b-gpe
:	:	o
and	cc	o
.	.	o
In	in	o
the	dt	o
second	jj	o
phase	nn	o
,	,	o
these	dt	o
type	nn	o
parameters	nns	o
are	vbp	o
replaced	vbn	o
with	in	o
their	prp$	o
respective	jj	o
types	nns	o
.	.	o
It	prp	o
does	vbz	o
n't	rb	o
matter	vb	o
in	in	o
which	wdt	o
order	nn	o
this	dt	o
happens	vbz	o
.	.	o
Starting	vbg	o
with	in	o
the	dt	o
state	nn	o
of	in	o
M	nnp	o
after	in	o
the	dt	o
first	jj	o
phase	nn	o
:	:	o
→	nn	o
,	,	o
→	nn	o
,	,	o
→	nn	o
Replace	nnp	o
on	in	o
the	dt	o
right-hand	jj	o
side	nn	o
of	in	o
→	nn	o
with	in	o
:	:	o
→	nn	o
,	,	o
→	nn	o
,	,	o
→	nn	o
Replace	nnp	o
on	in	o
the	dt	o
right-hand	jj	o
side	nn	o
of	in	o
→	nn	o
with	in	o
:	:	o
→	nn	o
,	,	o
→	nn	o
,	,	o
→	nn	o
At	in	o
this	dt	o
point	nn	o
no	dt	o
further	jj	o
substitution	nn	o
is	vbz	o
possible	jj	o
and	cc	o
the	dt	o
map	nn	o
is	vbz	o
full	jj	o
.	.	o
Therefore	rb	o
,	,	o
represents	vbz	o
the	dt	o
final	jj	o
map	nn	o
of	in	o
type	nn	o
parameters	nns	o
to	to	o
type	nn	o
arguments	nns	o
for	in	o
the	dt	o
given	vbn	o
type	nn	o
parameter	nn	o
list	nn	o
.	.	o
Operators	nnps	o
Operators	nnps	o
combine	vb	o
operands	nns	o
into	in	o
expressions	nns	o
.	.	o
Comparisons	nns	o
are	vbp	o
discussed	vbn	o
elsewhere	rb	o
.	.	o
For	in	o
other	jj	o
binary	jj	o
operators	nns	o
,	,	o
the	dt	o
operand	nn	o
types	nns	o
must	md	o
be	vb	o
identical	jj	o
unless	in	o
the	dt	o
operation	nn	o
involves	vbz	o
shifts	nns	o
or	cc	o
untyped	jj	o
constants	nns	o
.	.	o
For	in	o
operations	nns	o
involving	vbg	o
constants	nns	o
only	rb	o
,	,	o
see	vbp	o
the	dt	o
section	nn	o
on	in	o
constant	nn	o
expressions	nns	o
.	.	o
Except	in	o
for	in	o
shift	nn	o
operations	nns	o
,	,	o
if	in	o
one	nn	o
operand	nn	o
is	vbz	o
an	dt	o
untyped	jj	o
constant	nn	o
and	cc	o
the	dt	o
other	jj	o
operand	nn	o
is	vbz	o
not	rb	o
,	,	o
the	dt	o
constant	nn	o
is	vbz	o
implicitly	rb	o
converted	vbn	o
to	to	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
other	jj	o
operand	nn	o
.	.	o
The	dt	o
right	nn	o
operand	nn	o
in	in	o
a	dt	o
shift	nn	o
expression	nn	o
must	md	o
have	vb	o
integer	jj	o
type	nn	o
or	cc	o
be	vb	o
an	dt	o
untyped	jj	o
constant	nn	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
.	.	o
If	in	o
the	dt	o
left	nn	o
operand	nn	o
of	in	o
a	dt	o
non-constant	jj	o
shift	nn	o
expression	nn	o
is	vbz	o
an	dt	o
untyped	jj	o
constant	nn	o
,	,	o
it	prp	o
is	vbz	o
first	jj	o
implicitly	rb	o
converted	vbn	o
to	to	o
the	dt	o
type	nn	o
it	prp	o
would	md	o
assume	vb	o
if	in	o
the	dt	o
shift	nn	o
expression	nn	o
were	vbd	o
replaced	vbn	o
by	in	o
its	prp$	o
left	nn	o
operand	nn	o
alone	rb	o
.	.	o
Operator	nn	o
precedence	nn	o
Unary	nnp	o
operators	nns	o
have	vb	o
the	dt	o
highest	jjs	o
precedence	nn	o
.	.	o
As	in	o
the	dt	o
and	cc	o
operators	nns	o
form	nn	o
statements	nns	o
,	,	o
not	rb	o
expressions	nns	o
,	,	o
they	prp	o
fall	vbp	o
outside	in	o
the	dt	o
operator	nn	o
hierarchy	nn	o
.	.	o
As	in	o
a	dt	o
consequence	nn	o
,	,	o
statement	nn	o
is	vbz	o
the	dt	o
same	jj	o
as	in	o
.	.	o
There	ex	o
are	vbp	o
five	cd	o
precedence	nn	o
levels	nns	o
for	in	o
binary	jj	o
operators	nns	o
.	.	o
Multiplication	nn	o
operators	nns	o
bind	vbp	o
strongest	jjs	o
,	,	o
followed	vbn	o
by	in	o
addition	nn	o
operators	nns	o
,	,	o
comparison	nn	o
operators	nns	o
,	,	o
(	(	o
logical	jj	o
AND	nnp	b-gpe
)	)	o
,	,	o
and	cc	o
finally	rb	o
(	(	o
logical	jj	o
OR	nnp	o
)	)	o
:	:	o
Precedence	nn	o
Operator	nn	o
5	cd	o
*	-none-	o
/	vbp	o
%	nn	o
<<	nnp	o
>>	nnp	o
&	cc	o
&^	vbp	o
4	cd	o
+	jj	o
-	-	o
|	vbp	o
^	nnp	o
3	cd	o
==	cc	o
!=	nn	o
<	nnp	o
<=	rb	o
>	nn	o
>=	jj	o
2	cd	o
&&	nnp	o
1	cd	o
||	nnp	o
Binary	nnp	o
operators	nns	o
of	in	o
the	dt	o
same	jj	o
precedence	nn	o
associate	nn	o
from	in	o
left	nn	o
to	to	o
right	vb	o
.	.	o
For	in	o
instance	nn	o
,	,	o
is	vbz	o
the	dt	o
same	jj	o
as	in	o
.	.	o
Arithmetic	jj	b-gpe
operators	nns	o
Arithmetic	jj	b-gpe
operators	nns	o
apply	vbp	o
to	to	o
numeric	jj	o
values	nns	o
and	cc	o
yield	vb	o
a	dt	o
result	nn	o
of	in	o
the	dt	o
same	jj	o
type	nn	o
as	in	o
the	dt	o
first	jj	o
operand	nn	o
.	.	o
The	dt	o
four	cd	o
standard	vbn	o
arithmetic	nn	o
operators	nns	o
(	(	o
,	,	o
,	,	o
,	,	o
)	)	o
apply	vbp	o
to	to	o
integer	nn	o
,	,	o
floating-point	jj	o
,	,	o
and	cc	o
complex	jj	o
types	nns	o
;	:	o
also	rb	o
applies	nns	o
to	to	o
strings	nns	o
.	.	o
The	dt	o
bitwise	nn	o
logical	jj	o
and	cc	o
shift	nn	o
operators	nns	o
apply	vbp	o
to	to	o
integers	nns	o
only	rb	o
.	.	o
+	jj	o
sum	jj	o
integers	nns	o
,	,	o
floats	nns	o
,	,	o
complex	jj	o
values	nns	o
,	,	o
strings	nns	o
-	-	o
difference	nn	o
integers	nns	o
,	,	o
floats	nns	o
,	,	o
complex	jj	o
values	nns	o
*	-none-	o
product	nn	o
integers	nns	o
,	,	o
floats	nns	o
,	,	o
complex	jj	o
values	nns	o
/	vbp	o
quotient	nn	o
integers	nns	o
,	,	o
floats	nns	o
,	,	o
complex	jj	o
values	nns	o
%	nn	o
remainder	nn	o
integers	nns	o
&	cc	o
bitwise	nn	o
AND	nnp	b-gpe
integers	nns	o
|	vbp	o
bitwise	nn	o
OR	nnp	o
integers	nns	o
^	nnp	o
bitwise	nn	o
XOR	nn	o
integers	nns	o
&^	vbp	o
bit	nn	o
clear	jj	o
(	(	o
AND	nnp	b-person
NOT	nnp	o
)	)	o
integers	nns	o
<<	nnp	o
left	nn	o
shift	nn	o
integer	jj	o
<<	nnp	o
integer	jj	o
>=	jj	o
0	-none-	o
>>	nnp	o
right	nn	o
shift	nn	o
integer	jj	o
>>	nnp	o
integer	jj	o
>=	jj	o
0	-none-	o
Excluding	nnp	o
shifts	nns	o
,	,	o
if	in	o
the	dt	o
operand	nn	o
type	nn	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
it	prp	o
must	md	o
have	vb	o
specific	jj	o
types	nns	o
,	,	o
and	cc	o
the	dt	o
operator	nn	o
must	md	o
apply	vbp	o
to	to	o
each	dt	o
specific	jj	o
type	nn	o
.	.	o
The	dt	o
operands	nns	o
are	vbp	o
represented	vbn	o
as	in	o
values	nns	o
of	in	o
the	dt	o
type	nn	o
argument	nn	o
that	wdt	o
the	dt	o
type	nn	o
parameter	nn	o
is	vbz	o
instantiated	vbn	o
with	in	o
,	,	o
and	cc	o
the	dt	o
operation	nn	o
is	vbz	o
computed	vbn	o
with	in	o
the	dt	o
precision	nn	o
of	in	o
that	wdt	o
type	nn	o
argument	nn	o
.	.	o
For	in	o
example	nn	o
,	,	o
given	vbn	o
the	dt	o
function	nn	o
:	:	o
the	dt	o
product	nn	o
and	cc	o
the	dt	o
addition	nn	o
are	vbp	o
computed	vbn	o
with	in	o
or	cc	o
precision	nn	o
,	,	o
respectively	rb	o
,	,	o
depending	vbg	o
on	in	o
the	dt	o
type	nn	o
argument	nn	o
for	in	o
.	.	o
For	in	o
shifts	nns	o
,	,	o
the	dt	o
core	nn	o
type	nn	o
of	in	o
both	dt	o
operands	nns	o
must	md	o
be	vb	o
an	dt	o
integer	nn	o
.	.	o
Integer	jjr	o
operators	nns	o
For	in	o
two	cd	o
integer	jj	o
values	nns	o
and	cc	o
,	,	o
the	dt	o
integer	jj	o
quotient	nn	o
and	cc	o
remainder	nn	o
satisfy	vbp	o
the	dt	o
following	vbg	o
relationships	nns	o
:	:	o
with	in	o
truncated	vbn	o
towards	in	o
zero	nn	o
(	(	o
"	nnp	o
truncated	vbn	o
division	nn	o
"	nn	o
)	)	o
.	.	o
The	dt	o
one	nn	o
exception	nn	o
to	to	o
this	dt	o
rule	nn	o
is	vbz	o
that	wdt	o
if	in	o
the	dt	o
dividend	nn	o
is	vbz	o
the	dt	o
most	jjs	o
negative	jj	o
value	nn	o
for	in	o
the	dt	o
int	nn	o
type	nn	o
of	in	o
,	,	o
the	dt	o
quotient	nn	o
is	vbz	o
equal	vb	o
to	to	o
(	(	o
and	cc	o
)	)	o
due	jj	o
to	to	o
two	cd	o
integer	jj	o
overflow	in	o
:	:	o
If	in	o
the	dt	o
divisor	nn	o
is	vbz	o
a	dt	o
constant	nn	o
,	,	o
it	prp	o
must	md	o
not	rb	o
be	vb	o
zero	cd	o
.	.	o
If	in	o
the	dt	o
divisor	nn	o
is	vbz	o
zero	nn	o
at	in	o
run	jj	o
time	nn	o
,	,	o
a	dt	o
run-time	jj	o
panic	nn	o
occurs	nns	o
.	.	o
If	in	o
the	dt	o
dividend	nn	o
is	vbz	o
non-negative	jj	o
and	cc	o
the	dt	o
divisor	nn	o
is	vbz	o
a	dt	o
constant	nn	o
power	nn	o
of	in	o
2	cd	o
,	,	o
the	dt	o
division	nn	o
may	md	o
be	vb	o
replaced	vbn	o
by	in	o
a	dt	o
right	nn	o
shift	nn	o
,	,	o
and	cc	o
computing	vbg	o
the	dt	o
remainder	nn	o
may	md	o
be	vb	o
replaced	vbn	o
by	in	o
a	dt	o
bitwise	nn	o
AND	nnp	b-gpe
operation	nn	o
:	:	o
The	dt	o
shift	nn	o
operators	nns	o
shift	nn	o
the	dt	o
left	nn	o
operand	nn	o
by	in	o
the	dt	o
shift	nn	o
count	nn	o
specified	vbn	o
by	in	o
the	dt	o
right	nn	o
operand	nn	o
,	,	o
which	wdt	o
must	md	o
be	vb	o
non-negative	jj	o
.	.	o
If	in	o
the	dt	o
shift	nn	o
count	nn	o
is	vbz	o
negative	jj	o
at	in	o
run	jj	o
time	nn	o
,	,	o
a	dt	o
run-time	jj	o
panic	nn	o
occurs	nns	o
.	.	o
The	dt	o
shift	nn	o
operators	nns	o
implement	vb	o
arithmetic	nn	o
shifts	nns	o
if	in	o
the	dt	o
left	nn	o
operand	nn	o
is	vbz	o
a	dt	o
signed	vbn	o
integer	jj	o
and	cc	o
logical	jj	o
shifts	nns	o
if	in	o
it	prp	o
is	vbz	o
an	dt	o
unsigned	jj	o
integer	nn	o
.	.	o
There	ex	o
is	vbz	o
no	dt	o
upper	jj	o
limit	nn	o
on	in	o
the	dt	o
shift	nn	o
count	nn	o
.	.	o
Shifts	nns	o
behave	vbp	o
as	in	o
if	in	o
the	dt	o
left	nn	o
operand	nn	o
is	vbz	o
shifted	vbn	o
times	nns	o
by	in	o
1	cd	o
for	in	o
a	dt	o
shift	nn	o
count	nn	o
of	in	o
.	.	o
As	in	o
a	dt	o
result	nn	o
,	,	o
is	vbz	o
the	dt	o
same	jj	o
as	in	o
and	cc	o
is	vbz	o
the	dt	o
same	jj	o
as	in	o
but	cc	o
truncated	vbn	o
towards	in	o
negative	jj	o
infinity	nn	o
.	.	o
For	in	o
integer	jj	o
operands	nns	o
,	,	o
the	dt	o
unary	jj	o
operators	nns	o
,	,	o
,	,	o
and	cc	o
are	vbp	o
defined	vbn	o
as	in	o
follows	vbz	o
:	:	o
+x	nn	o
is	vbz	o
0	-none-	o
+	jj	o
x	nnp	o
-x	nnp	o
negation	nn	o
is	vbz	o
0	-none-	o
-	-	o
x	nnp	o
^x	nnp	o
bitwise	nn	o
complement	nn	o
is	vbz	o
m	nn	o
^	nnp	o
x	nnp	o
with	in	o
m	nn	o
=	nnp	o
"	vbp	o
all	dt	o
bits	nns	o
set	nn	o
to	to	o
1	cd	o
"	nn	o
for	in	o
unsigned	jj	o
x	nnp	o
and	cc	o
m	nn	o
=	nnp	o
-1	nn	o
for	in	o
signed	vbn	o
x	nnp	o
Integer	jjr	o
overflow	nn	o
For	in	o
unsigned	jj	o
integer	jj	o
values	nns	o
,	,	o
the	dt	o
operations	nns	o
,	,	o
,	,	o
,	,	o
and	cc	o
are	vbp	o
computed	vbn	o
modulo	jj	o
2n	cd	o
,	,	o
where	wrb	o
n	in	o
is	vbz	o
the	dt	o
bit	nn	o
width	nn	o
of	in	o
the	dt	o
unsigned	jj	o
integer	nn	o
's	pos	o
type	nn	o
.	.	o
Loosely	rb	o
speaking	vbg	o
,	,	o
these	dt	o
unsigned	jj	o
integer	jj	o
operations	nns	o
discard	vb	o
high	jj	o
bits	nns	o
upon	in	o
overflow	nn	o
,	,	o
and	cc	o
programs	nns	o
may	md	o
rely	vb	o
on	in	o
"	jj	o
wrap	nn	o
around	in	o
"	nnp	o
.	.	o
For	in	o
signed	vbn	o
integers	nns	o
,	,	o
the	dt	o
operations	nns	o
,	,	o
,	,	o
,	,	o
,	,	o
and	cc	o
may	md	o
legally	rb	o
overflow	nn	o
and	cc	o
the	dt	o
resulting	vbg	o
value	nn	o
exists	vbz	o
and	cc	o
is	vbz	o
deterministically	rb	o
defined	vbn	o
by	in	o
the	dt	o
signed	vbn	o
integer	jj	o
representation	nn	o
,	,	o
the	dt	o
operation	nn	o
,	,	o
and	cc	o
its	prp$	o
operands	nns	o
.	.	o
Overflow	nnp	b-person
does	vbz	o
not	rb	o
cause	vb	o
a	dt	o
run-time	jj	o
panic	nn	o
.	.	o
A	dt	o
compiler	nn	o
may	md	o
not	rb	o
optimize	vb	o
code	nn	o
under	in	o
the	dt	o
assumption	nn	o
that	wdt	o
overflow	nn	o
does	vbz	o
not	rb	o
occur	vb	o
.	.	o
For	in	o
instance	nn	o
,	,	o
it	prp	o
may	md	o
not	rb	o
assume	vb	o
that	wdt	o
is	vbz	o
always	rb	o
true	jj	o
.	.	o
Floating-point	jj	o
operators	nns	o
For	in	o
floating-point	nn	o
and	cc	o
complex	jj	o
numbers	nns	o
,	,	o
is	vbz	o
the	dt	o
same	jj	o
as	in	o
,	,	o
while	in	o
is	vbz	o
the	dt	o
negation	nn	o
of	in	o
.	.	o
The	dt	o
result	nn	o
of	in	o
a	dt	o
floating-point	nn	o
or	cc	o
complex	jj	o
division	nn	o
by	in	o
zero	nn	o
is	vbz	o
not	rb	o
specified	vbn	o
beyond	in	o
the	dt	o
IEEE-754	jj	o
standard	nn	o
;	:	o
whether	in	o
a	dt	o
run-time	jj	o
panic	nn	o
occurs	nn	o
is	vbz	o
implementation-specific	jj	o
.	.	o
An	dt	o
implementation	nn	o
may	md	o
combine	vb	o
multiple	nn	o
floating-point	nn	o
operations	nns	o
into	in	o
a	dt	o
single	jj	o
fused	jj	o
operation	nn	o
,	,	o
possibly	rb	o
across	in	o
statements	nns	o
,	,	o
and	cc	o
produce	vb	o
a	dt	o
result	nn	o
that	wdt	o
differs	nns	o
from	in	o
the	dt	o
value	nn	o
obtained	vbn	o
by	in	o
executing	vbg	o
and	cc	o
rounding	nn	o
the	dt	o
instructions	nns	o
individually	rb	o
.	.	o
An	dt	o
explicit	jj	o
floating-point	nn	o
type	nn	o
conversion	nn	o
rounds	vbz	o
to	to	o
the	dt	o
precision	nn	o
of	in	o
the	dt	o
target	nn	o
type	nn	o
,	,	o
preventing	vbg	o
fusion	nn	o
that	wdt	o
would	md	o
discard	vb	o
that	wdt	o
rounding	vbg	o
.	.	o
For	in	o
instance	nn	o
,	,	o
some	dt	o
architectures	vbz	o
provide	vbp	o
a	dt	o
"	nn	o
fused	vbn	o
multiply	nn	o
and	cc	o
add	vb	o
"	nnp	o
(	(	o
FMA	nnp	o
)	)	o
instruction	nn	o
that	wdt	o
computes	vbz	o
without	in	o
rounding	nn	o
the	dt	o
intermediate	jj	o
result	nn	o
.	.	o
These	dt	o
examples	nns	o
show	vbp	o
when	wrb	o
a	dt	o
Go	nnp	o
implementation	nn	o
can	md	o
use	vbp	o
that	wdt	o
instruction	nn	o
:	:	o
String	vbg	o
concatenation	nn	o
Strings	nns	o
can	md	o
be	vb	o
concatenated	vbn	o
using	vbg	o
the	dt	o
operator	nn	o
or	cc	o
the	dt	o
assignment	nn	o
operator	nn	o
:	:	o
String	vbg	o
addition	nn	o
creates	vbz	o
a	dt	o
new	jj	o
string	vbg	o
by	in	o
concatenating	vbg	o
the	dt	o
operands	nns	o
.	.	o
Comparison	nnp	o
operators	nns	o
Comparison	nnp	o
operators	nns	o
compare	vbp	o
two	cd	o
operands	nns	o
and	cc	o
yield	vb	o
an	dt	o
untyped	jj	o
boolean	jj	o
value	nn	o
.	.	o
==	cc	o
equal	vb	o
!=	nn	o
not	rb	o
equal	vb	o
<	nnp	o
less	jjr	o
<=	rb	o
less	jjr	o
or	cc	o
equal	vb	o
>	nn	o
greater	jjr	o
>=	jj	o
greater	jjr	o
or	cc	o
equal	vb	o
In	in	o
any	dt	o
comparison	nn	o
,	,	o
the	dt	o
first	jj	o
operand	nn	o
must	md	o
be	vb	o
assignable	jj	o
to	to	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
second	jj	o
operand	nn	o
,	,	o
or	cc	o
vice	nn	o
versa	nn	o
.	.	o
The	dt	o
equality	nn	o
operators	nns	o
and	cc	o
apply	vbp	o
to	to	o
operands	nns	o
that	wdt	o
are	vbp	o
comparable	jj	o
.	.	o
The	dt	o
ordering	nn	o
operators	nns	o
,	,	o
,	,	o
,	,	o
and	cc	o
apply	vbp	o
to	to	o
operands	nns	o
that	wdt	o
are	vbp	o
ordered	vbn	o
.	.	o
These	dt	o
terms	nns	o
and	cc	o
the	dt	o
result	nn	o
of	in	o
the	dt	o
comparisons	nns	o
are	vbp	o
defined	vbn	o
as	in	o
follows	vbz	o
:	:	o
Boolean	jj	b-gpe
values	nns	o
are	vbp	o
comparable	jj	o
.	.	o
Two	cd	o
boolean	jj	o
values	nns	o
are	vbp	o
equal	vb	o
if	in	o
they	prp	o
are	vbp	o
either	dt	o
both	dt	o
or	cc	o
both	dt	o
.	.	o
Integer	jjr	o
values	nns	o
are	vbp	o
comparable	jj	o
and	cc	o
ordered	vbd	o
,	,	o
in	in	o
the	dt	o
usual	jj	o
way	nn	o
.	.	o
Floating-point	jj	o
values	nns	o
are	vbp	o
comparable	jj	o
and	cc	o
ordered	vbd	o
,	,	o
as	in	o
defined	vbn	o
by	in	o
the	dt	o
IEEE-754	jj	o
standard	nn	o
.	.	o
Complex	jj	o
values	nns	o
are	vbp	o
comparable	jj	o
.	.	o
Two	cd	o
complex	jj	o
values	nns	o
and	cc	o
are	vbp	o
equal	vb	o
if	in	o
both	dt	o
and	cc	o
.	.	o
String	vbg	o
values	nns	o
are	vbp	o
comparable	jj	o
and	cc	o
ordered	vbd	o
,	,	o
lexically	rb	o
byte-wise	nn	o
.	.	o
Pointer	nnp	o
values	nns	o
are	vbp	o
comparable	jj	o
.	.	o
Two	cd	o
pointer	nn	o
values	nns	o
are	vbp	o
equal	vb	o
if	in	o
they	prp	o
point	nn	o
to	to	o
the	dt	o
same	jj	o
variable	nn	o
or	cc	o
if	in	o
both	dt	o
have	vb	o
value	nn	o
.	.	o
Pointers	nns	o
to	to	o
distinct	jj	o
zero-size	jj	o
variables	nns	o
may	md	o
or	cc	o
may	md	o
not	rb	o
be	vb	o
equal	jj	o
.	.	o
Channel	nnp	o
values	nns	o
are	vbp	o
comparable	jj	o
.	.	o
Two	cd	o
channel	nns	o
values	nns	o
are	vbp	o
equal	vb	o
if	in	o
they	prp	o
were	vbd	o
created	vbn	o
by	in	o
the	dt	o
same	jj	o
call	nn	o
to	to	o
or	cc	o
if	in	o
both	dt	o
have	vb	o
value	nn	o
.	.	o
Interface	nnp	o
values	nns	o
are	vbp	o
comparable	jj	o
.	.	o
Two	cd	o
interface	nn	o
values	nns	o
are	vbp	o
equal	vb	o
if	in	o
they	prp	o
have	vb	o
identical	jj	o
dynamic	jj	o
types	nns	o
and	cc	o
equal	vb	o
dynamic	jj	o
values	nns	o
or	cc	o
if	in	o
both	dt	o
have	vb	o
value	nn	o
.	.	o
A	dt	o
value	nn	o
of	in	o
non-interface	jj	o
type	nn	o
and	cc	o
a	dt	o
value	nn	o
of	in	o
interface	nn	o
type	nn	o
are	vbp	o
comparable	jj	o
when	wrb	o
values	nns	o
of	in	o
type	nn	o
are	vbp	o
comparable	jj	o
and	cc	o
implements	vbz	o
.	.	o
They	prp	o
are	vbp	o
equal	vb	o
if	in	o
's	pos	o
dynamic	jj	o
type	nn	o
is	vbz	o
identical	jj	o
to	to	o
and	cc	o
's	pos	o
dynamic	jj	o
value	nn	o
is	vbz	o
equal	vb	o
to	to	o
.	.	o
Struct	nnp	o
values	nns	o
are	vbp	o
comparable	jj	o
if	in	o
all	pdt	o
their	prp$	o
fields	nns	o
are	vbp	o
comparable	jj	o
.	.	o
Two	cd	o
struct	nn	o
values	nns	o
are	vbp	o
equal	vb	o
if	in	o
their	prp$	o
corresponding	jj	o
non-blank	jj	o
fields	nns	o
are	vbp	o
equal	jj	o
.	.	o
Array	nn	o
values	nns	o
are	vbp	o
comparable	jj	o
if	in	o
values	nns	o
of	in	o
the	dt	o
array	nn	o
element	nn	o
type	nn	o
are	vbp	o
comparable	jj	o
.	.	o
Two	cd	o
array	nn	o
values	nns	o
are	vbp	o
equal	vb	o
if	in	o
their	prp$	o
corresponding	jj	o
elements	nns	o
are	vbp	o
equal	jj	o
.	.	o
A	dt	o
comparison	nn	o
of	in	o
two	cd	o
interface	nn	o
values	nns	o
with	in	o
identical	jj	o
dynamic	jj	o
types	nns	o
causes	vbz	o
a	dt	o
run-time	jj	o
panic	nn	o
if	in	o
values	nns	o
of	in	o
that	wdt	o
type	nn	o
are	vbp	o
not	rb	o
comparable	jj	o
.	.	o
This	dt	o
behavior	nn	o
applies	nns	o
not	rb	o
only	rb	o
to	to	o
direct	vb	o
interface	nn	o
value	nn	o
comparisons	nns	o
but	cc	o
also	rb	o
when	wrb	o
comparing	vbg	o
arrays	nns	o
of	in	o
interface	nn	o
values	nns	o
or	cc	o
structs	nns	o
with	in	o
interface-valued	jj	o
fields	nns	o
.	.	o
Slice	nnp	o
,	,	o
map	nn	o
,	,	o
and	cc	o
function	nn	o
values	nns	o
are	vbp	o
not	rb	o
comparable	jj	o
.	.	o
However	rb	o
,	,	o
as	in	o
a	dt	o
special	jj	o
case	nn	o
,	,	o
a	dt	o
slice	nn	o
,	,	o
map	nn	o
,	,	o
or	cc	o
function	nn	o
value	nn	o
may	md	o
be	vb	o
compared	vbn	o
to	to	o
the	dt	o
predeclared	jj	o
identifier	nn	o
.	.	o
Comparison	nnp	o
of	in	o
pointer	nn	o
,	,	o
channel	nn	o
,	,	o
and	cc	o
interface	nn	o
values	nns	o
to	to	o
is	vbz	o
also	rb	o
allowed	vbn	o
and	cc	o
follows	vbz	o
from	in	o
the	dt	o
general	jj	o
rules	nns	o
above	in	o
.	.	o
Logical	jj	o
operators	nns	o
Logical	jj	o
operators	nns	o
apply	vbp	o
to	to	o
boolean	jj	o
values	nns	o
and	cc	o
yield	vb	o
a	dt	o
result	nn	o
of	in	o
the	dt	o
same	jj	o
type	nn	o
as	in	o
the	dt	o
operands	nns	o
.	.	o
The	dt	o
right	nn	o
operand	nn	o
is	vbz	o
evaluated	vbn	o
conditionally	rb	o
.	.	o
&&	nnp	o
conditional	jj	o
AND	nnp	b-gpe
p	jj	o
&&	nnp	o
q	nn	o
is	vbz	o
"	jj	o
if	in	o
p	jj	o
then	rb	o
q	nn	o
else	rb	o
false	jj	o
"	nnp	o
||	nnp	o
conditional	jj	o
OR	nnp	o
p	jj	o
||	nnp	o
q	nn	o
is	vbz	o
"	jj	o
if	in	o
p	jj	o
then	rb	o
true	jj	o
else	rb	o
q	jj	o
"	nn	o
!	.	o
NOT	nnp	b-person
!p	nnp	o
is	vbz	o
"	jj	o
not	rb	o
p	jj	o
"	nnp	o
Address	nnp	o
operators	nns	o
For	in	o
an	dt	o
operand	nn	o
of	in	o
type	nn	o
,	,	o
the	dt	o
address	nn	o
operation	nn	o
generates	vbz	o
a	dt	o
pointer	nn	o
of	in	o
type	nn	o
to	to	o
.	.	o
The	dt	o
operand	nn	o
must	md	o
be	vb	o
addressable	jj	o
,	,	o
that	wdt	o
is	vbz	o
,	,	o
either	dt	o
a	dt	o
variable	jj	o
,	,	o
pointer	nn	o
indirection	nn	o
,	,	o
or	cc	o
slice	nn	o
indexing	nn	o
operation	nn	o
;	:	o
or	cc	o
a	dt	o
field	nn	o
selector	nn	o
of	in	o
an	dt	o
addressable	jj	o
struct	nn	o
operand	nn	o
;	:	o
or	cc	o
an	dt	o
array	nn	o
indexing	nn	o
operation	nn	o
of	in	o
an	dt	o
addressable	jj	o
array	nn	o
.	.	o
As	in	o
an	dt	o
exception	nn	o
to	to	o
the	dt	o
addressability	nn	o
requirement	nn	o
,	,	o
may	md	o
also	rb	o
be	vb	o
a	dt	o
(	(	o
possibly	rb	o
parenthesized	vbn	o
)	)	o
composite	jj	o
literal	jj	o
.	.	o
If	in	o
the	dt	o
evaluation	nn	o
of	in	o
would	md	o
cause	vb	o
a	dt	o
run-time	jj	o
panic	nn	o
,	,	o
then	rb	o
the	dt	o
evaluation	nn	o
of	in	o
does	vbz	o
too	rb	o
.	.	o
For	in	o
an	dt	o
operand	nn	o
of	in	o
pointer	nn	o
type	nn	o
,	,	o
the	dt	o
pointer	nn	o
indirection	nn	o
denotes	vbz	o
the	dt	o
variable	nn	o
of	in	o
type	nn	o
pointed	vbn	o
to	to	o
by	in	o
.	.	o
If	in	o
is	vbz	o
,	,	o
an	dt	o
attempt	nn	o
to	to	o
evaluate	vbp	o
will	md	o
cause	vb	o
a	dt	o
run-time	jj	o
panic	nn	o
.	.	o
Receive	nnp	o
operator	nn	o
For	in	o
an	dt	o
operand	nn	o
whose	wp$	o
core	nn	o
type	nn	o
is	vbz	o
a	dt	o
channel	nn	o
,	,	o
the	dt	o
value	nn	o
of	in	o
the	dt	o
receive	nn	o
operation	nn	o
is	vbz	o
the	dt	o
value	nn	o
received	jj	o
from	in	o
the	dt	o
channel	nns	o
.	.	o
The	dt	o
channel	nns	o
direction	nn	o
must	md	o
permit	vb	o
receive	nn	o
operations	nns	o
,	,	o
and	cc	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
receive	nn	o
operation	nn	o
is	vbz	o
the	dt	o
element	nn	o
type	nn	o
of	in	o
the	dt	o
channel	nn	o
.	.	o
The	dt	o
expression	nn	o
blocks	vbz	o
until	in	o
a	dt	o
value	nn	o
is	vbz	o
available	jj	o
.	.	o
Receiving	vbg	o
from	in	o
a	dt	o
channel	nns	o
blocks	vbz	o
forever	rb	o
.	.	o
A	dt	o
receive	nn	o
operation	nn	o
on	in	o
a	dt	o
closed	jj	o
channel	nns	o
can	md	o
always	rb	o
proceed	vb	o
immediately	rb	o
,	,	o
yielding	vbg	o
the	dt	o
element	nn	o
type	nn	o
's	pos	o
zero	nn	o
value	nn	o
after	in	o
any	dt	o
previously	rb	o
sent	vbn	o
values	nns	o
have	vb	o
been	vbn	o
received	vbn	o
.	.	o
A	dt	o
receive	nn	o
expression	nn	o
used	vbn	o
in	in	o
an	dt	o
assignment	nn	o
or	cc	o
initialization	nn	o
of	in	o
the	dt	o
special	jj	o
form	nn	o
yields	nns	o
an	dt	o
additional	jj	o
untyped	jj	o
boolean	jj	o
result	nn	o
reporting	nn	o
whether	in	o
the	dt	o
communication	nn	o
succeeded	vbd	o
.	.	o
The	dt	o
value	nn	o
of	in	o
is	vbz	o
if	in	o
the	dt	o
value	nn	o
received	jj	o
was	vbd	o
delivered	vbn	o
by	in	o
a	dt	o
successful	jj	o
send	vb	o
operation	nn	o
to	to	o
the	dt	o
channel	nn	o
,	,	o
or	cc	o
if	in	o
it	prp	o
is	vbz	o
a	dt	o
zero	nn	o
value	nn	o
generated	vbn	o
because	in	o
the	dt	o
channel	nns	o
is	vbz	o
closed	jj	o
and	cc	o
empty	jj	o
.	.	o
Conversions	nns	o
A	dt	o
conversion	nn	o
changes	vbz	o
the	dt	o
type	nn	o
of	in	o
an	dt	o
expression	nn	o
to	to	o
the	dt	o
type	nn	o
specified	vbn	o
by	in	o
the	dt	o
conversion	nn	o
.	.	o
A	dt	o
conversion	nn	o
may	md	o
appear	vbp	o
literally	rb	o
in	in	o
the	dt	o
source	nn	o
,	,	o
or	cc	o
it	prp	o
may	md	o
be	vb	o
implied	vbn	o
by	in	o
the	dt	o
context	nn	o
in	in	o
which	wdt	o
an	dt	o
expression	nn	o
appears	vbz	o
.	.	o
An	dt	o
explicit	jj	o
conversion	nn	o
is	vbz	o
an	dt	o
expression	nn	o
of	in	o
the	dt	o
form	nn	o
where	wrb	o
is	vbz	o
a	dt	o
type	nn	o
and	cc	o
is	vbz	o
an	dt	o
expression	nn	o
that	wdt	o
can	md	o
be	vb	o
converted	vbn	o
to	to	o
type	nn	o
.	.	o
If	in	o
the	dt	o
type	nn	o
starts	vbz	o
with	in	o
the	dt	o
operator	nn	o
or	cc	o
,	,	o
or	cc	o
if	in	o
the	dt	o
type	nn	o
starts	vbz	o
with	in	o
the	dt	o
keyword	nn	o
and	cc	o
has	vbz	o
no	dt	o
result	nn	o
list	nn	o
,	,	o
it	prp	o
must	md	o
be	vb	o
parenthesized	vbn	o
when	wrb	o
necessary	jj	o
to	to	o
avoid	vb	o
ambiguity	nn	o
:	:	o
A	dt	o
constant	nn	o
value	nn	o
can	md	o
be	vb	o
converted	vbn	o
to	to	o
type	nn	o
if	in	o
is	vbz	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
.	.	o
As	in	o
a	dt	o
special	jj	o
case	nn	o
,	,	o
an	dt	o
integer	jj	o
constant	nn	o
can	md	o
be	vb	o
explicitly	rb	o
converted	vbn	o
to	to	o
a	dt	o
string	vbg	o
type	nn	o
using	vbg	o
the	dt	o
same	jj	o
rule	nn	o
as	in	o
for	in	o
non-constant	jj	o
.	.	o
Converting	vbg	o
a	dt	o
constant	nn	o
to	to	o
a	dt	o
type	nn	o
that	wdt	o
is	vbz	o
not	rb	o
a	dt	o
type	nn	o
parameter	nn	o
yields	nns	o
a	dt	o
typed	jj	o
constant	nn	o
.	.	o
Converting	vbg	o
a	dt	o
constant	nn	o
to	to	o
a	dt	o
type	nn	o
parameter	nn	o
yields	nns	o
a	dt	o
non-constant	jj	o
value	nn	o
of	in	o
that	wdt	o
type	nn	o
,	,	o
with	in	o
the	dt	o
value	nn	o
represented	vbn	o
as	in	o
a	dt	o
value	nn	o
of	in	o
the	dt	o
type	nn	o
argument	nn	o
that	wdt	o
the	dt	o
type	nn	o
parameter	nn	o
is	vbz	o
instantiated	vbn	o
with	in	o
.	.	o
For	in	o
example	nn	o
,	,	o
given	vbn	o
the	dt	o
function	nn	o
:	:	o
the	dt	o
conversion	nn	o
results	nns	o
in	in	o
a	dt	o
non-constant	jj	o
value	nn	o
of	in	o
type	nn	o
and	cc	o
the	dt	o
value	nn	o
is	vbz	o
represented	vbn	o
as	in	o
a	dt	o
or	cc	o
a	dt	o
depending	vbg	o
on	in	o
the	dt	o
type	nn	o
argument	nn	o
for	in	o
.	.	o
Accordingly	rb	o
,	,	o
if	in	o
is	vbz	o
instantiated	vbn	o
with	in	o
a	dt	o
type	nn	o
,	,	o
the	dt	o
numeric	jj	o
value	nn	o
of	in	o
the	dt	o
expression	nn	o
will	md	o
be	vb	o
computed	vbn	o
with	in	o
the	dt	o
same	jj	o
precision	nn	o
as	in	o
the	dt	o
corresponding	jj	o
non-constant	jj	o
addition	nn	o
.	.	o
A	dt	o
non-constant	jj	o
value	nn	o
can	md	o
be	vb	o
converted	vbn	o
to	to	o
type	nn	o
in	in	o
any	dt	o
of	in	o
these	dt	o
cases	nns	o
:	:	o
is	vbz	o
assignable	jj	o
to	to	o
.	.	o
ignoring	vbg	o
struct	nn	o
tags	nns	o
(	(	o
see	vb	o
below	in	o
)	)	o
,	,	o
's	pos	o
type	nn	o
and	cc	o
are	vbp	o
not	rb	o
type	nn	o
parameters	nns	o
but	cc	o
have	vb	o
identical	jj	o
underlying	jj	o
types	nns	o
.	.	o
ignoring	vbg	o
struct	nn	o
tags	nns	o
(	(	o
see	vb	o
below	in	o
)	)	o
,	,	o
's	pos	o
type	nn	o
and	cc	o
are	vbp	o
pointer	nn	o
types	nns	o
that	wdt	o
are	vbp	o
not	rb	o
named	vbn	o
types	nns	o
,	,	o
and	cc	o
their	prp$	o
pointer	nn	o
base	nn	o
types	nns	o
are	vbp	o
not	rb	o
type	nn	o
parameters	nns	o
but	cc	o
have	vb	o
identical	jj	o
underlying	jj	o
types	nns	o
.	.	o
's	pos	o
type	nn	o
and	cc	o
are	vbp	o
both	dt	o
integer	jj	o
or	cc	o
floating	vbg	o
point	nn	o
types	nns	o
.	.	o
's	pos	o
type	nn	o
and	cc	o
are	vbp	o
both	dt	o
complex	jj	o
types	nns	o
.	.	o
is	vbz	o
an	dt	o
integer	jj	o
or	cc	o
a	dt	o
slice	nn	o
of	in	o
bytes	nns	o
or	cc	o
runes	nns	o
and	cc	o
is	vbz	o
a	dt	o
string	vbg	o
type	nn	o
.	.	o
is	vbz	o
a	dt	o
string	vbg	o
and	cc	o
is	vbz	o
a	dt	o
slice	nn	o
of	in	o
bytes	nns	o
or	cc	o
runes	nns	o
.	.	o
is	vbz	o
a	dt	o
slice	nn	o
,	,	o
is	vbz	o
a	dt	o
pointer	nn	o
to	to	o
an	dt	o
array	vb	o
,	,	o
and	cc	o
the	dt	o
slice	nn	o
and	cc	o
array	nn	o
types	nns	o
have	vb	o
identical	jj	o
element	nn	o
types	nns	o
.	.	o
Additionally	rb	o
,	,	o
if	in	o
or	cc	o
's	pos	o
type	nn	o
are	vbp	o
type	nn	o
parameters	nns	o
with	in	o
specific	jj	o
types	nns	o
,	,	o
can	md	o
also	rb	o
be	vb	o
converted	vbn	o
to	to	o
type	nn	o
if	in	o
one	nn	o
of	in	o
the	dt	o
following	vbg	o
conditions	nns	o
applies	nns	o
:	:	o
Both	cc	o
and	cc	o
are	vbp	o
type	nn	o
parameters	nns	o
and	cc	o
a	dt	o
value	nn	o
of	in	o
each	dt	o
specific	jj	o
type	nn	o
of	in	o
can	md	o
be	vb	o
converted	vbn	o
to	to	o
each	dt	o
specific	jj	o
type	nn	o
of	in	o
.	.	o
Only	rb	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
and	cc	o
a	dt	o
value	nn	o
of	in	o
each	dt	o
specific	jj	o
type	nn	o
of	in	o
can	md	o
be	vb	o
converted	vbn	o
to	to	o
.	.	o
Only	rb	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
and	cc	o
can	md	o
be	vb	o
converted	vbn	o
to	to	o
each	dt	o
specific	jj	o
type	nn	o
of	in	o
.	.	o
Struct	nnp	o
tags	nns	o
are	vbp	o
ignored	vbn	o
when	wrb	o
comparing	vbg	o
struct	nn	o
types	nns	o
for	in	o
identity	nn	o
for	in	o
the	dt	o
purpose	nn	o
of	in	o
conversion	nn	o
:	:	o
Specific	jj	o
rules	nns	o
apply	vbp	o
to	to	o
(	(	o
non-constant	jj	o
)	)	o
conversions	nns	o
between	in	o
numeric	jj	o
types	nns	o
or	cc	o
to	to	o
and	cc	o
from	in	o
a	dt	o
string	vbg	o
type	nn	o
.	.	o
These	dt	o
conversions	nns	o
may	md	o
change	vbp	o
the	dt	o
representation	nn	o
of	in	o
and	cc	o
incur	vb	o
a	dt	o
run-time	jj	o
cost	nn	o
.	.	o
All	dt	o
other	jj	o
conversions	nns	o
only	rb	o
change	vbp	o
the	dt	o
type	nn	o
but	cc	o
not	rb	o
the	dt	o
representation	nn	o
of	in	o
.	.	o
There	ex	o
is	vbz	o
no	dt	o
linguistic	jj	o
mechanism	nn	o
to	to	o
convert	vb	o
between	in	o
pointers	nns	o
and	cc	o
integers	nns	o
.	.	o
The	dt	o
package	nn	o
implements	vbz	o
this	dt	o
functionality	nn	o
under	in	o
restricted	vbn	o
circumstances	nns	o
.	.	o
Conversions	nns	o
between	in	o
numeric	jj	o
types	nns	o
For	in	o
the	dt	o
conversion	nn	o
of	in	o
non-constant	jj	o
numeric	jj	o
values	nns	o
,	,	o
the	dt	o
following	vbg	o
rules	nns	o
apply	vbp	o
:	:	o
When	wrb	o
converting	vbg	o
between	in	o
integer	jj	o
types	nns	o
,	,	o
if	in	o
the	dt	o
value	nn	o
is	vbz	o
a	dt	o
signed	vbn	o
integer	nn	o
,	,	o
it	prp	o
is	vbz	o
sign	jj	o
extended	vbn	o
to	to	o
implicit	jj	o
infinite	jj	o
precision	nn	o
;	:	o
otherwise	rb	o
it	prp	o
is	vbz	o
zero	nn	o
extended	jj	o
.	.	o
It	prp	o
is	vbz	o
then	rb	o
truncated	vbn	o
to	to	o
fit	vb	o
in	in	o
the	dt	o
result	nn	o
type	nn	o
's	pos	o
size	nn	o
.	.	o
For	in	o
example	nn	o
,	,	o
if	in	o
,	,	o
then	rb	o
.	.	o
The	dt	o
conversion	nn	o
always	rb	o
yields	nns	o
a	dt	o
valid	jj	o
value	nn	o
;	:	o
there	ex	o
is	vbz	o
no	dt	o
indication	nn	o
of	in	o
overflow	nn	o
.	.	o
When	wrb	o
converting	vbg	o
a	dt	o
floating-point	nn	o
number	nn	o
to	to	o
an	dt	o
integer	nn	o
,	,	o
the	dt	o
fraction	nn	o
is	vbz	o
discarded	vbn	o
(	(	o
truncation	nn	o
towards	in	o
zero	nn	o
)	)	o
.	.	o
When	wrb	o
converting	vbg	o
an	dt	o
integer	jj	o
or	cc	o
floating-point	nn	o
number	nn	o
to	to	o
a	dt	o
floating-point	nn	o
type	nn	o
,	,	o
or	cc	o
a	dt	o
complex	jj	o
number	nn	o
to	to	o
another	dt	o
complex	jj	o
type	nn	o
,	,	o
the	dt	o
result	nn	o
value	nn	o
is	vbz	o
rounded	vbn	o
to	to	o
the	dt	o
precision	nn	o
specified	vbn	o
by	in	o
the	dt	o
destination	nn	o
type	nn	o
.	.	o
For	in	o
instance	nn	o
,	,	o
the	dt	o
value	nn	o
of	in	o
a	dt	o
variable	nn	o
of	in	o
type	nn	o
may	md	o
be	vb	o
stored	vbn	o
using	vbg	o
additional	jj	o
precision	nn	o
beyond	in	o
that	wdt	o
of	in	o
an	dt	o
IEEE-754	jj	o
32-bit	jj	o
number	nn	o
,	,	o
but	cc	o
float32(x	rb	o
)	)	o
represents	vbz	o
the	dt	o
result	nn	o
of	in	o
rounding	nn	o
's	pos	o
value	nn	o
to	to	o
32-bit	jj	o
precision	nn	o
.	.	o
Similarly	rb	o
,	,	o
may	md	o
use	vbp	o
more	jjr	o
than	in	o
32	cd	o
bits	nns	o
of	in	o
precision	nn	o
,	,	o
but	cc	o
does	vbz	o
not	rb	o
.	.	o
In	in	o
all	pdt	o
non-constant	jj	o
conversions	nns	o
involving	vbg	o
floating-point	nn	o
or	cc	o
complex	jj	o
values	nns	o
,	,	o
if	in	o
the	dt	o
result	nn	o
type	nn	o
cannot	vbp	o
represent	vbp	o
the	dt	o
value	nn	o
the	dt	o
conversion	nn	o
succeeds	vbz	o
but	cc	o
the	dt	o
result	nn	o
value	nn	o
is	vbz	o
implementation-dependent	jj	o
.	.	o
Conversions	nns	o
to	to	o
and	cc	o
from	in	o
a	dt	o
string	vbg	o
type	nn	o
Converting	vbg	o
a	dt	o
signed	vbn	o
or	cc	o
unsigned	jj	o
integer	jj	o
value	nn	o
to	to	o
a	dt	o
string	vbg	o
type	nn	o
yields	nns	o
a	dt	o
string	vbg	o
containing	vbg	o
the	dt	o
UTF-8	jj	o
representation	nn	o
of	in	o
the	dt	o
integer	nn	o
.	.	o
Values	nns	o
outside	in	o
the	dt	o
range	nn	o
of	in	o
valid	jj	o
Unicode	nnp	b-gpe
code	nn	o
points	nns	o
are	vbp	o
converted	vbn	o
to	to	o
.	.	o
Converting	vbg	o
a	dt	o
slice	nn	o
of	in	o
bytes	nns	o
to	to	o
a	dt	o
string	vbg	o
type	nn	o
yields	nns	o
a	dt	o
string	vbg	o
whose	wp$	o
successive	jj	o
bytes	nns	o
are	vbp	o
the	dt	o
elements	nns	o
of	in	o
the	dt	o
slice	nn	o
.	.	o
Converting	vbg	o
a	dt	o
slice	nn	o
of	in	o
runes	nns	o
to	to	o
a	dt	o
string	vbg	o
type	nn	o
yields	nns	o
a	dt	o
string	vbg	o
that	wdt	o
is	vbz	o
the	dt	o
concatenation	nn	o
of	in	o
the	dt	o
individual	jj	o
rune	nns	o
values	nns	o
converted	vbn	o
to	to	o
strings	nns	o
.	.	o
Converting	vbg	o
a	dt	o
value	nn	o
of	in	o
a	dt	o
string	vbg	o
type	nn	o
to	to	o
a	dt	o
slice	nn	o
of	in	o
bytes	nns	o
type	nn	o
yields	nns	o
a	dt	o
slice	nn	o
whose	wp$	o
successive	jj	o
elements	nns	o
are	vbp	o
the	dt	o
bytes	nns	o
of	in	o
the	dt	o
string	nn	o
.	.	o
Converting	vbg	o
a	dt	o
value	nn	o
of	in	o
a	dt	o
string	vbg	o
type	nn	o
to	to	o
a	dt	o
slice	nn	o
of	in	o
runes	nns	o
type	nn	o
yields	nns	o
a	dt	o
slice	nn	o
containing	vbg	o
the	dt	o
individual	jj	o
Unicode	nnp	b-gpe
code	nn	o
points	nns	o
of	in	o
the	dt	o
string	nn	o
.	.	o
Conversions	nns	o
from	in	o
slice	nn	o
to	to	o
array	nn	o
pointer	nn	o
Converting	vbg	o
a	dt	o
slice	nn	o
to	to	o
an	dt	o
array	nn	o
pointer	nn	o
yields	nns	o
a	dt	o
pointer	nn	o
to	to	o
the	dt	o
underlying	jj	o
array	nn	o
of	in	o
the	dt	o
slice	nn	o
.	.	o
If	in	o
the	dt	o
length	nn	o
of	in	o
the	dt	o
slice	nn	o
is	vbz	o
less	jjr	o
than	in	o
the	dt	o
length	nn	o
of	in	o
the	dt	o
array	vb	o
,	,	o
a	dt	o
run-time	jj	o
panic	nn	o
occurs	nns	o
.	.	o
Constant	jj	o
expressions	nns	o
Constant	jj	o
expressions	nns	o
may	md	o
contain	vb	o
only	rb	o
constant	nn	o
operands	nns	o
and	cc	o
are	vbp	o
evaluated	vbn	o
at	in	o
compile	jj	o
time	nn	o
.	.	o
Untyped	jj	o
boolean	nn	o
,	,	o
numeric	jj	o
,	,	o
and	cc	o
string	vbg	o
constants	nns	o
may	md	o
be	vb	o
used	vbn	o
as	in	o
operands	nns	o
wherever	in	o
it	prp	o
is	vbz	o
legal	jj	o
to	to	o
use	vbp	o
an	dt	o
operand	nn	o
of	in	o
boolean	nn	o
,	,	o
numeric	jj	o
,	,	o
or	cc	o
string	vbg	o
type	nn	o
,	,	o
respectively	rb	o
.	.	o
A	dt	o
constant	nn	o
comparison	nn	o
always	rb	o
yields	nns	o
an	dt	o
untyped	jj	o
boolean	jj	o
constant	nn	o
.	.	o
If	in	o
the	dt	o
left	nn	o
operand	nn	o
of	in	o
a	dt	o
constant	nn	o
shift	nn	o
expression	nn	o
is	vbz	o
an	dt	o
untyped	jj	o
constant	nn	o
,	,	o
the	dt	o
result	nn	o
is	vbz	o
an	dt	o
integer	jj	o
constant	nn	o
;	:	o
otherwise	rb	o
it	prp	o
is	vbz	o
a	dt	o
constant	nn	o
of	in	o
the	dt	o
same	jj	o
type	nn	o
as	in	o
the	dt	o
left	nn	o
operand	nn	o
,	,	o
which	wdt	o
must	md	o
be	vb	o
of	in	o
integer	jj	o
type	nn	o
.	.	o
Any	dt	o
other	jj	o
operation	nn	o
on	in	o
untyped	jj	o
constants	nns	o
results	nns	o
in	in	o
an	dt	o
untyped	jj	o
constant	nn	o
of	in	o
the	dt	o
same	jj	o
kind	nn	o
;	:	o
that	wdt	o
is	vbz	o
,	,	o
a	dt	o
boolean	nn	o
,	,	o
integer	nn	o
,	,	o
floating-point	jj	o
,	,	o
complex	jj	o
,	,	o
or	cc	o
string	vbg	o
constant	nn	o
.	.	o
If	in	o
the	dt	o
untyped	jj	o
operands	nns	o
of	in	o
a	dt	o
binary	jj	o
operation	nn	o
(	(	o
other	jj	o
than	in	o
a	dt	o
shift	nn	o
)	)	o
are	vbp	o
of	in	o
different	jj	o
kinds	nns	o
,	,	o
the	dt	o
result	nn	o
is	vbz	o
of	in	o
the	dt	o
operand	nn	o
's	pos	o
kind	nn	o
that	wdt	o
appears	vbz	o
later	rb	o
in	in	o
this	dt	o
list	nn	o
:	:	o
integer	nn	o
,	,	o
rune	nn	o
,	,	o
floating-point	jj	o
,	,	o
complex	jj	o
.	.	o
For	in	o
example	nn	o
,	,	o
an	dt	o
untyped	jj	o
integer	jj	o
constant	nn	o
divided	vbn	o
by	in	o
an	dt	o
untyped	jj	o
complex	jj	o
constant	nn	o
yields	nns	o
an	dt	o
untyped	jj	o
complex	jj	o
constant	nn	o
.	.	o
Applying	vbg	o
the	dt	o
built-in	jj	o
function	nn	o
to	to	o
untyped	jj	o
integer	nn	o
,	,	o
rune	nn	o
,	,	o
or	cc	o
floating-point	nn	o
constants	nns	o
yields	nns	o
an	dt	o
untyped	jj	o
complex	jj	o
constant	nn	o
.	.	o
Constant	jj	o
expressions	nns	o
are	vbp	o
always	rb	o
evaluated	vbn	o
exactly	rb	o
;	:	o
intermediate	jj	o
values	nns	o
and	cc	o
the	dt	o
constants	nns	o
themselves	prp	o
may	md	o
require	vb	o
precision	nn	o
significantly	rb	o
larger	jjr	o
than	in	o
supported	vbn	o
by	in	o
any	dt	o
predeclared	jj	o
type	nn	o
in	in	o
the	dt	o
language	nn	o
.	.	o
The	dt	o
following	vbg	o
are	vbp	o
legal	jj	o
declarations	nns	o
:	:	o
The	dt	o
divisor	nn	o
of	in	o
a	dt	o
constant	nn	o
division	nn	o
or	cc	o
remainder	nn	o
operation	nn	o
must	md	o
not	rb	o
be	vb	o
zero	nn	o
:	:	o
The	dt	o
values	nns	o
of	in	o
typed	jj	o
constants	nns	o
must	md	o
always	rb	o
be	vb	o
accurately	rb	o
representable	jj	o
by	in	o
values	nns	o
of	in	o
the	dt	o
constant	nn	o
type	nn	o
.	.	o
The	dt	o
following	vbg	o
constant	nn	o
expressions	nns	o
are	vbp	o
illegal	jj	o
:	:	o
The	dt	o
mask	nn	o
used	vbn	o
by	in	o
the	dt	o
unary	jj	o
bitwise	nn	o
complement	nn	o
operator	nn	o
matches	nns	o
the	dt	o
rule	nn	o
for	in	o
non-constants	nns	o
:	:	o
the	dt	o
mask	nn	o
is	vbz	o
all	pdt	o
1s	cd	o
for	in	o
unsigned	jj	o
constants	nns	o
and	cc	o
-1	nn	o
for	in	o
signed	vbn	o
and	cc	o
untyped	jj	o
constants	nns	o
.	.	o
Implementation	nnp	o
restriction	nn	o
:	:	o
A	dt	o
compiler	nn	o
may	md	o
use	vbp	o
rounding	nn	o
while	in	o
computing	vbg	o
untyped	jj	o
floating-point	nn	o
or	cc	o
complex	jj	o
constant	nn	o
expressions	nns	o
;	:	o
see	vbp	o
the	dt	o
implementation	nn	o
restriction	nn	o
in	in	o
the	dt	o
section	nn	o
on	in	o
constants	nns	o
.	.	o
This	dt	o
rounding	nn	o
may	md	o
cause	vb	o
a	dt	o
floating-point	nn	o
constant	nn	o
expression	nn	o
to	to	o
be	vb	o
invalid	jj	o
in	in	o
an	dt	o
integer	jj	o
context	nn	o
,	,	o
even	rb	o
if	in	o
it	prp	o
would	md	o
be	vb	o
integral	jj	o
when	wrb	o
calculated	vbn	o
using	vbg	o
infinite	jj	o
precision	nn	o
,	,	o
and	cc	o
vice	nn	o
versa	nn	o
.	.	o
Order	nn	o
of	in	o
evaluation	nn	o
At	in	o
package	nn	o
level	nn	o
,	,	o
initialization	nn	o
dependencies	nns	o
determine	vb	o
the	dt	o
evaluation	nn	o
order	nn	o
of	in	o
individual	jj	o
initialization	nn	o
expressions	nns	o
in	in	o
variable	nn	o
declarations	nns	o
.	.	o
Otherwise	rb	o
,	,	o
when	wrb	o
evaluating	vbg	o
the	dt	o
operands	nns	o
of	in	o
an	dt	o
expression	nn	o
,	,	o
assignment	nn	o
,	,	o
or	cc	o
return	vb	o
statement	nn	o
,	,	o
all	pdt	o
function	nn	o
calls	nns	o
,	,	o
method	nn	o
calls	nns	o
,	,	o
and	cc	o
communication	nn	o
operations	nns	o
are	vbp	o
evaluated	vbn	o
in	in	o
lexical	jj	o
left-to-right	jj	o
order	nn	o
.	.	o
For	in	o
example	nn	o
,	,	o
in	in	o
the	dt	o
(	(	o
function-local	jj	o
)	)	o
assignment	nn	o
the	dt	o
function	nn	o
calls	vbz	o
and	cc	o
communication	nn	o
happen	vb	o
in	in	o
the	dt	o
order	nn	o
,	,	o
,	,	o
,	,	o
,	,	o
,	,	o
,	,	o
and	cc	o
.	.	o
However	rb	o
,	,	o
the	dt	o
order	nn	o
of	in	o
those	dt	o
events	nns	o
compared	vbn	o
to	to	o
the	dt	o
evaluation	nn	o
and	cc	o
indexing	nn	o
of	in	o
and	cc	o
the	dt	o
evaluation	nn	o
of	in	o
is	vbz	o
not	rb	o
specified	vbn	o
.	.	o
At	in	o
package	nn	o
level	nn	o
,	,	o
initialization	nn	o
dependencies	nns	o
override	in	o
the	dt	o
left-to-right	jj	o
rule	nn	o
for	in	o
individual	jj	o
initialization	nn	o
expressions	nns	o
,	,	o
but	cc	o
not	rb	o
for	in	o
operands	nns	o
within	in	o
each	dt	o
expression	nn	o
:	:	o
The	dt	o
function	nn	o
calls	vbz	o
happen	vb	o
in	in	o
the	dt	o
order	nn	o
,	,	o
,	,	o
,	,	o
,	,	o
,	,	o
and	cc	o
.	.	o
Floating-point	jj	o
operations	nns	o
within	in	o
a	dt	o
single	jj	o
expression	nn	o
are	vbp	o
evaluated	vbn	o
according	vbg	o
to	to	o
the	dt	o
associativity	nn	o
of	in	o
the	dt	o
operators	nns	o
.	.	o
Explicit	nnp	b-person
parentheses	vbz	o
affect	vbp	o
the	dt	o
evaluation	nn	o
by	in	o
overriding	vbg	o
the	dt	o
default	nn	o
associativity	nn	o
.	.	o
In	in	o
the	dt	o
expression	nn	o
the	dt	o
addition	nn	o
is	vbz	o
performed	vbn	o
before	in	o
adding	vbg	o
.	.	o
Statements	nns	o
Statements	nns	o
control	vbp	o
execution	nn	o
.	.	o
Terminating	vbg	o
statements	nns	o
A	dt	o
terminating	nn	o
statement	nn	o
interrupts	vbz	o
the	dt	o
regular	jj	o
flow	vb	o
of	in	o
control	vbp	o
in	in	o
a	dt	o
block	nn	o
.	.	o
The	dt	o
following	vbg	o
statements	nns	o
are	vbp	o
terminating	vbg	o
:	:	o
A	dt	o
"	jj	o
return	nn	o
"	nnp	o
or	cc	o
"	jj	o
goto	nn	o
"	nnp	o
statement	nn	o
.	.	o
A	dt	o
call	nn	o
to	to	o
the	dt	o
built-in	jj	o
function	nn	o
.	.	o
A	dt	o
block	nn	o
in	in	o
which	wdt	o
the	dt	o
statement	nn	o
list	nn	o
ends	vbz	o
in	in	o
a	dt	o
terminating	nn	o
statement	nn	o
.	.	o
An	dt	o
"	nn	o
if	in	o
"	jj	o
statement	nn	o
in	in	o
which	wdt	o
:	:	o
the	dt	o
"	nn	o
else	rb	o
"	nnp	o
branch	nn	o
is	vbz	o
present	jj	o
,	,	o
and	cc	o
both	dt	o
branches	nns	o
are	vbp	o
terminating	nn	o
statements	nns	o
.	.	o
A	dt	o
"	nn	o
for	in	o
"	nnp	o
statement	nn	o
in	in	o
which	wdt	o
:	:	o
there	ex	o
are	vbp	o
no	dt	o
"	nnp	o
break	nn	o
"	nnp	o
statements	nns	o
referring	vbg	o
to	to	o
the	dt	o
"	nn	o
for	in	o
"	nnp	o
statement	nn	o
,	,	o
and	cc	o
the	dt	o
loop	nn	o
condition	nn	o
is	vbz	o
absent	jj	o
,	,	o
and	cc	o
the	dt	o
"	nn	o
for	in	o
"	nnp	o
statement	nn	o
does	vbz	o
not	rb	o
use	vbp	o
a	dt	o
range	nn	o
clause	nn	o
.	.	o
A	dt	o
"	nnp	o
switch	nn	o
"	nnp	o
statement	nn	o
in	in	o
which	wdt	o
:	:	o
there	ex	o
are	vbp	o
no	dt	o
"	nnp	o
break	nn	o
"	nnp	o
statements	nns	o
referring	vbg	o
to	to	o
the	dt	o
"	nnp	o
switch	nn	o
"	nnp	o
statement	nn	o
,	,	o
there	ex	o
is	vbz	o
a	dt	o
default	nn	o
case	nn	o
,	,	o
and	cc	o
the	dt	o
statement	nn	o
lists	nns	o
in	in	o
each	dt	o
case	nn	o
,	,	o
including	vbg	o
the	dt	o
default	nn	o
,	,	o
end	nn	o
in	in	o
a	dt	o
terminating	nn	o
statement	nn	o
,	,	o
or	cc	o
a	dt	o
possibly	rb	o
labeled	jj	o
"	nnp	o
fallthrough	in	o
"	nnp	o
statement	nn	o
.	.	o
A	dt	o
"	vb	o
select	jj	o
"	nnp	o
statement	nn	o
in	in	o
which	wdt	o
:	:	o
there	ex	o
are	vbp	o
no	dt	o
"	nnp	o
break	nn	o
"	nnp	o
statements	nns	o
referring	vbg	o
to	to	o
the	dt	o
"	vb	o
select	jj	o
"	nnp	o
statement	nn	o
,	,	o
and	cc	o
the	dt	o
statement	nn	o
lists	nns	o
in	in	o
each	dt	o
case	nn	o
,	,	o
including	vbg	o
the	dt	o
default	nn	o
if	in	o
present	jj	o
,	,	o
end	nn	o
in	in	o
a	dt	o
terminating	nn	o
statement	nn	o
.	.	o
A	dt	o
labeled	jj	o
statement	nn	o
labeling	vbg	o
a	dt	o
terminating	nn	o
statement	nn	o
.	.	o
All	dt	o
other	jj	o
statements	nns	o
are	vbp	o
not	rb	o
terminating	vbg	o
.	.	o
A	dt	o
statement	nn	o
list	nn	o
ends	vbz	o
in	in	o
a	dt	o
terminating	nn	o
statement	nn	o
if	in	o
the	dt	o
list	nn	o
is	vbz	o
not	rb	o
empty	jj	o
and	cc	o
its	prp$	o
final	jj	o
non-empty	jj	o
statement	nn	o
is	vbz	o
terminating	vbg	o
.	.	o
Empty	jj	o
statements	nns	o
The	dt	o
empty	jj	o
statement	nn	o
does	vbz	o
nothing	nn	o
.	.	o
Labeled	vbn	o
statements	nns	o
A	dt	o
labeled	jj	o
statement	nn	o
may	md	o
be	vb	o
the	dt	o
target	nn	o
of	in	o
a	dt	o
,	,	o
or	cc	o
statement	nn	o
.	.	o
Expression	nn	o
statements	nns	o
With	in	o
the	dt	o
exception	nn	o
of	in	o
specific	jj	o
built-in	jj	o
functions	nns	o
,	,	o
function	nn	o
and	cc	o
method	nn	o
calls	vbz	o
and	cc	o
receive	nn	o
operations	nns	o
can	md	o
appear	vbp	o
in	in	o
statement	nn	o
context	nn	o
.	.	o
Such	jj	o
statements	nns	o
may	md	o
be	vb	o
parenthesized	vbn	o
.	.	o
The	dt	o
following	vbg	o
built-in	jj	o
functions	nns	o
are	vbp	o
not	rb	o
permitted	vbn	o
in	in	o
statement	nn	o
context	nn	o
:	:	o
Send	jj	o
statements	nns	o
A	dt	o
send	vb	o
statement	nn	o
sends	vbz	o
a	dt	o
value	nn	o
on	in	o
a	dt	o
channel	nn	o
.	.	o
The	dt	o
channel	nns	o
expression	nn	o
's	pos	o
core	nn	o
type	nn	o
must	md	o
be	vb	o
a	dt	o
channel	nn	o
,	,	o
the	dt	o
channel	nns	o
direction	nn	o
must	md	o
permit	vb	o
send	vb	o
operations	nns	o
,	,	o
and	cc	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
value	nn	o
to	to	o
be	vb	o
sent	vbn	o
must	md	o
be	vb	o
assignable	jj	o
to	to	o
the	dt	o
channel	nn	o
's	pos	o
element	nn	o
type	nn	o
.	.	o
Both	cc	o
the	dt	o
channel	nns	o
and	cc	o
the	dt	o
value	nn	o
expression	nn	o
are	vbp	o
evaluated	vbn	o
before	in	o
communication	nn	o
begins	nns	o
.	.	o
Communication	nn	o
blocks	vbz	o
until	in	o
the	dt	o
send	vb	o
can	md	o
proceed	vb	o
.	.	o
A	dt	o
send	vb	o
on	in	o
an	dt	o
unbuffered	jj	o
channel	nns	o
can	md	o
proceed	vb	o
if	in	o
a	dt	o
receiver	nn	o
is	vbz	o
ready	jj	o
.	.	o
A	dt	o
send	vb	o
on	in	o
a	dt	o
buffered	vbd	o
channel	nns	o
can	md	o
proceed	vb	o
if	in	o
there	ex	o
is	vbz	o
room	nn	o
in	in	o
the	dt	o
buffer	nn	o
.	.	o
A	dt	o
send	vb	o
on	in	o
a	dt	o
closed	jj	o
channel	nns	o
proceeds	nns	o
by	in	o
causing	vbg	o
a	dt	o
run-time	jj	o
panic	nn	o
.	.	o
A	dt	o
send	vb	o
on	in	o
a	dt	o
channel	nns	o
blocks	vbz	o
forever	rb	o
.	.	o
IncDec	nnp	b-gpe
statements	nns	o
The	dt	o
"	nnp	o
++	nnp	o
"	nnp	o
and	cc	o
"	nnp	o
--	:	o
"	jj	o
statements	nns	o
increment	nn	o
or	cc	o
decrement	jj	o
their	prp$	o
operands	nns	o
by	in	o
the	dt	o
untyped	jj	o
constant	nn	o
.	.	o
As	in	o
with	in	o
an	dt	o
assignment	nn	o
,	,	o
the	dt	o
operand	nn	o
must	md	o
be	vb	o
addressable	jj	o
or	cc	o
a	dt	o
map	nn	o
index	nn	o
expression	nn	o
.	.	o
The	dt	o
following	vbg	o
assignment	nn	o
statements	nns	o
are	vbp	o
semantically	rb	o
equivalent	jj	o
:	:	o
IncDec	nnp	b-gpe
statement	nn	o
Assignment	nnp	o
x++	nnp	o
x	nnp	o
+=	vbd	o
1	cd	o
x--	jj	o
x	nnp	o
-=	nnp	o
1	cd	o
Assignments	nnp	o
Each	dt	o
left-hand	jj	o
side	nn	o
operand	nn	o
must	md	o
be	vb	o
addressable	jj	o
,	,	o
a	dt	o
map	nn	o
index	nn	o
expression	nn	o
,	,	o
or	cc	o
(	(	o
for	in	o
assignments	nns	o
only	rb	o
)	)	o
the	dt	o
blank	jj	o
identifier	nn	o
.	.	o
Operands	nns	o
may	md	o
be	vb	o
parenthesized	vbn	o
.	.	o
An	dt	o
assignment	nn	o
operation	nn	o
op	jj	o
where	wrb	o
op	jj	o
is	vbz	o
a	dt	o
binary	jj	o
arithmetic	nn	o
operator	nn	o
is	vbz	o
equivalent	jj	o
to	to	o
op	jj	o
but	cc	o
evaluates	vbz	o
only	rb	o
once	rb	o
.	.	o
The	dt	o
op	jj	o
construct	nn	o
is	vbz	o
a	dt	o
single	jj	o
token	nn	o
.	.	o
In	in	o
assignment	nn	o
operations	nns	o
,	,	o
both	dt	o
the	dt	o
left-	jj	o
and	cc	o
right-hand	jj	o
expression	nn	o
lists	nns	o
must	md	o
contain	vb	o
exactly	rb	o
one	nn	o
single-valued	jj	o
expression	nn	o
,	,	o
and	cc	o
the	dt	o
left-hand	jj	o
expression	nn	o
must	md	o
not	rb	o
be	vb	o
the	dt	o
blank	jj	o
identifier	nn	o
.	.	o
A	dt	o
tuple	jj	o
assignment	nn	o
assigns	vbz	o
the	dt	o
individual	jj	o
elements	nns	o
of	in	o
a	dt	o
multi-valued	jj	o
operation	nn	o
to	to	o
a	dt	o
list	nn	o
of	in	o
variables	nns	o
.	.	o
There	ex	o
are	vbp	o
two	cd	o
forms	nns	o
.	.	o
In	in	o
the	dt	o
first	jj	o
,	,	o
the	dt	o
right	nn	o
hand	nn	o
operand	nn	o
is	vbz	o
a	dt	o
single	jj	o
multi-valued	jj	o
expression	nn	o
such	jj	o
as	in	o
a	dt	o
function	nn	o
call	nn	o
,	,	o
a	dt	o
channel	nns	o
or	cc	o
map	nn	o
operation	nn	o
,	,	o
or	cc	o
a	dt	o
type	nn	o
assertion	nn	o
.	.	o
The	dt	o
number	nn	o
of	in	o
operands	nns	o
on	in	o
the	dt	o
left	nn	o
hand	nn	o
side	nn	o
must	md	o
match	vbp	o
the	dt	o
number	nn	o
of	in	o
values	nns	o
.	.	o
For	in	o
instance	nn	o
,	,	o
if	in	o
is	vbz	o
a	dt	o
function	nn	o
returning	vbg	o
two	cd	o
values	nns	o
,	,	o
assigns	vbz	o
the	dt	o
first	jj	o
value	nn	o
to	to	o
and	cc	o
the	dt	o
second	jj	o
to	to	o
.	.	o
In	in	o
the	dt	o
second	jj	o
form	nn	o
,	,	o
the	dt	o
number	nn	o
of	in	o
operands	nns	o
on	in	o
the	dt	o
left	nn	o
must	md	o
equal	vb	o
the	dt	o
number	nn	o
of	in	o
expressions	nns	o
on	in	o
the	dt	o
right	nn	o
,	,	o
each	dt	o
of	in	o
which	wdt	o
must	md	o
be	vb	o
single-valued	jj	o
,	,	o
and	cc	o
the	dt	o
nth	jj	o
expression	nn	o
on	in	o
the	dt	o
right	nn	o
is	vbz	o
assigned	vbn	o
to	to	o
the	dt	o
nth	jj	o
operand	nn	o
on	in	o
the	dt	o
left	nn	o
:	:	o
The	dt	o
blank	jj	o
identifier	nn	o
provides	vbz	o
a	dt	o
way	nn	o
to	to	o
ignore	vb	o
right-hand	jj	o
side	nn	o
values	nns	o
in	in	o
an	dt	o
assignment	nn	o
:	:	o
The	dt	o
assignment	nn	o
proceeds	nns	o
in	in	o
two	cd	o
phases	nns	o
.	.	o
First	nnp	o
,	,	o
the	dt	o
operands	nns	o
of	in	o
index	nn	o
expressions	nns	o
and	cc	o
pointer	nn	o
indirections	nns	o
(	(	o
including	vbg	o
implicit	jj	o
pointer	nn	o
indirections	nns	o
in	in	o
selectors	nns	o
)	)	o
on	in	o
the	dt	o
left	nn	o
and	cc	o
the	dt	o
expressions	nns	o
on	in	o
the	dt	o
right	nn	o
are	vbp	o
all	pdt	o
evaluated	vbn	o
in	in	o
the	dt	o
usual	jj	o
order	nn	o
.	.	o
Second	nnp	o
,	,	o
the	dt	o
assignments	nns	o
are	vbp	o
carried	vbn	o
out	in	o
in	in	o
left-to-right	jj	o
order	nn	o
.	.	o
In	in	o
assignments	nns	o
,	,	o
each	dt	o
value	nn	o
must	md	o
be	vb	o
assignable	jj	o
to	to	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
operand	nn	o
to	to	o
which	wdt	o
it	prp	o
is	vbz	o
assigned	vbn	o
,	,	o
with	in	o
the	dt	o
following	vbg	o
special	jj	o
cases	nns	o
:	:	o
Any	dt	o
typed	jj	o
value	nn	o
may	md	o
be	vb	o
assigned	vbn	o
to	to	o
the	dt	o
blank	jj	o
identifier	nn	o
.	.	o
If	in	o
an	dt	o
untyped	jj	o
constant	nn	o
is	vbz	o
assigned	vbn	o
to	to	o
a	dt	o
variable	nn	o
of	in	o
interface	nn	o
type	nn	o
or	cc	o
the	dt	o
blank	jj	o
identifier	nn	o
,	,	o
the	dt	o
constant	nn	o
is	vbz	o
first	jj	o
implicitly	rb	o
converted	vbn	o
to	to	o
its	prp$	o
default	nn	o
type	nn	o
.	.	o
If	in	o
an	dt	o
untyped	jj	o
boolean	jj	o
value	nn	o
is	vbz	o
assigned	vbn	o
to	to	o
a	dt	o
variable	nn	o
of	in	o
interface	nn	o
type	nn	o
or	cc	o
the	dt	o
blank	jj	o
identifier	nn	o
,	,	o
it	prp	o
is	vbz	o
first	jj	o
implicitly	rb	o
converted	vbn	o
to	to	o
type	nn	o
.	.	o
If	in	o
statements	nns	o
"	vbp	o
If	in	o
"	jj	o
statements	nns	o
specify	vb	o
the	dt	o
conditional	jj	o
execution	nn	o
of	in	o
two	cd	o
branches	nns	o
according	vbg	o
to	to	o
the	dt	o
value	nn	o
of	in	o
a	dt	o
boolean	jj	o
expression	nn	o
.	.	o
If	in	o
the	dt	o
expression	nn	o
evaluates	vbz	o
to	to	o
true	jj	o
,	,	o
the	dt	o
"	nn	o
if	in	o
"	jj	o
branch	nn	o
is	vbz	o
executed	vbn	o
,	,	o
otherwise	rb	o
,	,	o
if	in	o
present	jj	o
,	,	o
the	dt	o
"	nn	o
else	rb	o
"	nnp	o
branch	nn	o
is	vbz	o
executed	vbn	o
.	.	o
The	dt	o
expression	nn	o
may	md	o
be	vb	o
preceded	vbn	o
by	in	o
a	dt	o
simple	nn	o
statement	nn	o
,	,	o
which	wdt	o
executes	vbz	o
before	in	o
the	dt	o
expression	nn	o
is	vbz	o
evaluated	vbn	o
.	.	o
Switch	vb	o
statements	nns	o
"	jj	o
Switch	nnp	b-gpe
"	nn	o
statements	nns	o
provide	vbp	o
multi-way	jj	o
execution	nn	o
.	.	o
An	dt	o
expression	nn	o
or	cc	o
type	nn	o
is	vbz	o
compared	vbn	o
to	to	o
the	dt	o
"	nn	o
cases	nns	o
"	nnp	o
inside	in	o
the	dt	o
"	nnp	o
switch	nn	o
"	nnp	o
to	to	o
determine	vb	o
which	wdt	o
branch	nn	o
to	to	o
execute	vb	o
.	.	o
There	ex	o
are	vbp	o
two	cd	o
forms	nns	o
:	:	o
expression	nn	o
switches	vbz	o
and	cc	o
type	nn	o
switches	nns	o
.	.	o
In	in	o
an	dt	o
expression	nn	o
switch	nn	o
,	,	o
the	dt	o
cases	nns	o
contain	vb	o
expressions	nns	o
that	wdt	o
are	vbp	o
compared	vbn	o
against	in	o
the	dt	o
value	nn	o
of	in	o
the	dt	o
switch	vb	o
expression	nn	o
.	.	o
In	in	o
a	dt	o
type	nn	o
switch	nn	o
,	,	o
the	dt	o
cases	nns	o
contain	vb	o
types	nns	o
that	wdt	o
are	vbp	o
compared	vbn	o
against	in	o
the	dt	o
type	nn	o
of	in	o
a	dt	o
specially	rb	o
annotated	vbn	o
switch	vb	o
expression	nn	o
.	.	o
The	dt	o
switch	vb	o
expression	nn	o
is	vbz	o
evaluated	vbn	o
exactly	rb	o
once	rb	o
in	in	o
a	dt	o
switch	vb	o
statement	nn	o
.	.	o
Expression	nn	o
switches	vbz	o
In	in	o
an	dt	o
expression	nn	o
switch	nn	o
,	,	o
the	dt	o
switch	vb	o
expression	nn	o
is	vbz	o
evaluated	vbn	o
and	cc	o
the	dt	o
case	nn	o
expressions	nns	o
,	,	o
which	wdt	o
need	md	o
not	rb	o
be	vb	o
constants	nns	o
,	,	o
are	vbp	o
evaluated	vbn	o
left-to-right	jj	o
and	cc	o
top-to-bottom	jj	o
;	:	o
the	dt	o
first	jj	o
one	nn	o
that	wdt	o
equals	vbz	o
the	dt	o
switch	vb	o
expression	nn	o
triggers	nns	o
execution	nn	o
of	in	o
the	dt	o
statements	nns	o
of	in	o
the	dt	o
associated	jj	o
case	nn	o
;	:	o
the	dt	o
other	jj	o
cases	nns	o
are	vbp	o
skipped	vbn	o
.	.	o
If	in	o
no	dt	o
case	nn	o
matches	nns	o
and	cc	o
there	ex	o
is	vbz	o
a	dt	o
"	jj	o
default	nn	o
"	nnp	o
case	nn	o
,	,	o
its	prp$	o
statements	nns	o
are	vbp	o
executed	vbn	o
.	.	o
There	ex	o
can	md	o
be	vb	o
at	in	o
most	jjs	o
one	nn	o
default	nn	o
case	nn	o
and	cc	o
it	prp	o
may	md	o
appear	vbp	o
anywhere	rb	o
in	in	o
the	dt	o
"	nnp	o
switch	nn	o
"	nnp	o
statement	nn	o
.	.	o
A	dt	o
missing	jj	o
switch	vb	o
expression	nn	o
is	vbz	o
equivalent	jj	o
to	to	o
the	dt	o
boolean	jj	o
value	nn	o
.	.	o
If	in	o
the	dt	o
switch	vb	o
expression	nn	o
evaluates	vbz	o
to	to	o
an	dt	o
untyped	jj	o
constant	nn	o
,	,	o
it	prp	o
is	vbz	o
first	jj	o
implicitly	rb	o
converted	vbn	o
to	to	o
its	prp$	o
default	nn	o
type	nn	o
.	.	o
The	dt	o
predeclared	jj	o
untyped	jj	o
value	nn	o
cannot	vbp	o
be	vb	o
used	vbn	o
as	in	o
a	dt	o
switch	vb	o
expression	nn	o
.	.	o
The	dt	o
switch	vb	o
expression	nn	o
type	nn	o
must	md	o
be	vb	o
comparable	jj	o
.	.	o
If	in	o
a	dt	o
case	nn	o
expression	nn	o
is	vbz	o
untyped	jj	o
,	,	o
it	prp	o
is	vbz	o
first	jj	o
implicitly	rb	o
converted	vbn	o
to	to	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
switch	vb	o
expression	nn	o
.	.	o
For	in	o
each	dt	o
(	(	o
possibly	rb	o
converted	vbn	o
)	)	o
case	nn	o
expression	nn	o
and	cc	o
the	dt	o
value	nn	o
of	in	o
the	dt	o
switch	vb	o
expression	nn	o
,	,	o
must	md	o
be	vb	o
a	dt	o
valid	jj	o
comparison	nn	o
.	.	o
In	in	o
other	jj	o
words	nns	o
,	,	o
the	dt	o
switch	vb	o
expression	nn	o
is	vbz	o
treated	vbn	o
as	in	o
if	in	o
it	prp	o
were	vbd	o
used	vbn	o
to	to	o
declare	vb	o
and	cc	o
initialize	vb	o
a	dt	o
temporary	jj	o
variable	nn	o
without	in	o
explicit	jj	o
type	nn	o
;	:	o
it	prp	o
is	vbz	o
that	wdt	o
value	nn	o
of	in	o
against	in	o
which	wdt	o
each	dt	o
case	nn	o
expression	nn	o
is	vbz	o
tested	vbn	o
for	in	o
equality	nn	o
.	.	o
In	in	o
a	dt	o
case	nn	o
or	cc	o
default	nn	o
clause	nn	o
,	,	o
the	dt	o
last	jj	o
non-empty	jj	o
statement	nn	o
may	md	o
be	vb	o
a	dt	o
(	(	o
possibly	rb	o
labeled	vbn	o
)	)	o
"	nnp	o
fallthrough	in	o
"	nnp	o
statement	nn	o
to	to	o
indicate	vb	o
that	wdt	o
control	vbp	o
should	md	o
flow	vb	o
from	in	o
the	dt	o
end	nn	o
of	in	o
this	dt	o
clause	nn	o
to	to	o
the	dt	o
first	jj	o
statement	nn	o
of	in	o
the	dt	o
next	jj	o
clause	nn	o
.	.	o
Otherwise	vb	o
control	vbp	o
flows	vbz	o
to	to	o
the	dt	o
end	nn	o
of	in	o
the	dt	o
"	nnp	o
switch	nn	o
"	nnp	o
statement	nn	o
.	.	o
A	dt	o
"	nnp	o
fallthrough	in	o
"	nnp	o
statement	nn	o
may	md	o
appear	vbp	o
as	in	o
the	dt	o
last	jj	o
statement	nn	o
of	in	o
all	pdt	o
but	cc	o
the	dt	o
last	jj	o
clause	nn	o
of	in	o
an	dt	o
expression	nn	o
switch	nn	o
.	.	o
The	dt	o
switch	vb	o
expression	nn	o
may	md	o
be	vb	o
preceded	vbn	o
by	in	o
a	dt	o
simple	nn	o
statement	nn	o
,	,	o
which	wdt	o
executes	vbz	o
before	in	o
the	dt	o
expression	nn	o
is	vbz	o
evaluated	vbn	o
.	.	o
Implementation	nnp	o
restriction	nn	o
:	:	o
A	dt	o
compiler	nn	o
may	md	o
disallow	vb	o
multiple	nn	o
case	nn	o
expressions	nns	o
evaluating	vbg	o
to	to	o
the	dt	o
same	jj	o
constant	nn	o
.	.	o
For	in	o
instance	nn	o
,	,	o
the	dt	o
current	jj	o
compilers	nns	o
disallow	vb	o
duplicate	vb	o
integer	nn	o
,	,	o
floating	vbg	o
point	nn	o
,	,	o
or	cc	o
string	vbg	o
constants	nns	o
in	in	o
case	nn	o
expressions	nns	o
.	.	o
Type	nnp	b-person
switches	vbz	o
A	dt	o
type	nn	o
switch	vb	o
compares	vbz	o
types	nns	o
rather	rb	o
than	in	o
values	nns	o
.	.	o
It	prp	o
is	vbz	o
otherwise	rb	o
similar	jj	o
to	to	o
an	dt	o
expression	nn	o
switch	nn	o
.	.	o
It	prp	o
is	vbz	o
marked	vbn	o
by	in	o
a	dt	o
special	jj	o
switch	vb	o
expression	nn	o
that	wdt	o
has	vbz	o
the	dt	o
form	nn	o
of	in	o
a	dt	o
type	nn	o
assertion	nn	o
using	vbg	o
the	dt	o
keyword	nn	o
rather	rb	o
than	in	o
an	dt	o
actual	jj	o
type	nn	o
:	:	o
Cases	nns	o
then	rb	o
match	vbp	o
actual	jj	o
types	nns	o
against	in	o
the	dt	o
dynamic	jj	o
type	nn	o
of	in	o
the	dt	o
expression	nn	o
.	.	o
As	in	o
with	in	o
type	nn	o
assertions	nns	o
,	,	o
must	md	o
be	vb	o
of	in	o
interface	nn	o
type	nn	o
,	,	o
but	cc	o
not	rb	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
and	cc	o
each	dt	o
non-interface	jj	o
type	nn	o
listed	vbn	o
in	in	o
a	dt	o
case	nn	o
must	md	o
implement	vb	o
the	dt	o
type	nn	o
of	in	o
.	.	o
The	dt	o
types	nns	o
listed	vbn	o
in	in	o
the	dt	o
cases	nns	o
of	in	o
a	dt	o
type	nn	o
switch	vb	o
must	md	o
all	pdt	o
be	vb	o
different	jj	o
.	.	o
The	dt	o
TypeSwitchGuard	nnp	b-gpe
may	md	o
include	vb	o
a	dt	o
short	jj	o
variable	nn	o
declaration	nn	o
.	.	o
When	wrb	o
that	wdt	o
form	nn	o
is	vbz	o
used	vbn	o
,	,	o
the	dt	o
variable	nn	o
is	vbz	o
declared	vbn	o
at	in	o
the	dt	o
end	nn	o
of	in	o
the	dt	o
TypeSwitchCase	nnp	o
in	in	o
the	dt	o
implicit	jj	o
block	nn	o
of	in	o
each	dt	o
clause	nn	o
.	.	o
In	in	o
clauses	nns	o
with	in	o
a	dt	o
case	nn	o
listing	vbg	o
exactly	rb	o
one	nn	o
type	nn	o
,	,	o
the	dt	o
variable	nn	o
has	vbz	o
that	wdt	o
type	nn	o
;	:	o
otherwise	rb	o
,	,	o
the	dt	o
variable	nn	o
has	vbz	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
expression	nn	o
in	in	o
the	dt	o
TypeSwitchGuard	nnp	b-gpe
.	.	o
Instead	rb	o
of	in	o
a	dt	o
type	nn	o
,	,	o
a	dt	o
case	nn	o
may	md	o
use	vbp	o
the	dt	o
predeclared	jj	o
identifier	nn	o
;	:	o
that	wdt	o
case	nn	o
is	vbz	o
selected	vbn	o
when	wrb	o
the	dt	o
expression	nn	o
in	in	o
the	dt	o
TypeSwitchGuard	nnp	b-gpe
is	vbz	o
a	dt	o
interface	nn	o
value	nn	o
.	.	o
There	ex	o
may	md	o
be	vb	o
at	in	o
most	jjs	o
one	nn	o
case	nn	o
.	.	o
Given	vbn	o
an	dt	o
expression	nn	o
of	in	o
type	nn	o
,	,	o
the	dt	o
following	vbg	o
type	nn	o
switch	nn	o
:	:	o
could	md	o
be	vb	o
rewritten	vbn	o
:	:	o
A	dt	o
type	nn	o
parameter	nn	o
or	cc	o
a	dt	o
generic	jj	o
type	nn	o
may	md	o
be	vb	o
used	vbn	o
as	in	o
a	dt	o
type	nn	o
in	in	o
a	dt	o
case	nn	o
.	.	o
If	in	o
upon	in	o
instantiation	nn	o
that	wdt	o
type	nn	o
turns	vbz	o
out	in	o
to	to	o
duplicate	vb	o
another	dt	o
entry	nn	o
in	in	o
the	dt	o
switch	nn	o
,	,	o
the	dt	o
first	jj	o
matching	nn	o
case	nn	o
is	vbz	o
chosen	vbn	o
.	.	o
The	dt	o
type	nn	o
switch	vb	o
guard	nn	o
may	md	o
be	vb	o
preceded	vbn	o
by	in	o
a	dt	o
simple	nn	o
statement	nn	o
,	,	o
which	wdt	o
executes	vbz	o
before	in	o
the	dt	o
guard	nn	o
is	vbz	o
evaluated	vbn	o
.	.	o
The	dt	o
"	nnp	o
fallthrough	in	o
"	nnp	o
statement	nn	o
is	vbz	o
not	rb	o
permitted	vbn	o
in	in	o
a	dt	o
type	nn	o
switch	nn	o
.	.	o
For	in	o
statements	nns	o
A	dt	o
"	nn	o
for	in	o
"	nnp	o
statement	nn	o
specifies	vbz	o
repeated	jj	o
execution	nn	o
of	in	o
a	dt	o
block	nn	o
.	.	o
There	ex	o
are	vbp	o
three	cd	o
forms	nns	o
:	:	o
The	dt	o
iteration	nn	o
may	md	o
be	vb	o
controlled	vbn	o
by	in	o
a	dt	o
single	jj	o
condition	nn	o
,	,	o
a	dt	o
"	nn	o
for	in	o
"	nnp	o
clause	nn	o
,	,	o
or	cc	o
a	dt	o
"	nnp	o
range	nn	o
"	nnp	o
clause	nn	o
.	.	o
For	in	o
statements	nns	o
with	in	o
single	jj	o
condition	nn	o
In	in	o
its	prp$	o
simplest	jjs	o
form	nn	o
,	,	o
a	dt	o
"	nn	o
for	in	o
"	nnp	o
statement	nn	o
specifies	vbz	o
the	dt	o
repeated	jj	o
execution	nn	o
of	in	o
a	dt	o
block	nn	o
as	in	o
long	rb	o
as	in	o
a	dt	o
boolean	jj	o
condition	nn	o
evaluates	vbz	o
to	to	o
true	jj	o
.	.	o
The	dt	o
condition	nn	o
is	vbz	o
evaluated	vbn	o
before	in	o
each	dt	o
iteration	nn	o
.	.	o
If	in	o
the	dt	o
condition	nn	o
is	vbz	o
absent	jj	o
,	,	o
it	prp	o
is	vbz	o
equivalent	jj	o
to	to	o
the	dt	o
boolean	jj	o
value	nn	o
.	.	o
For	in	o
statements	nns	o
with	in	o
clause	nn	o
A	dt	o
"	nn	o
for	in	o
"	nnp	o
statement	nn	o
with	in	o
a	dt	o
ForClause	nnp	o
is	vbz	o
also	rb	o
controlled	vbn	o
by	in	o
its	prp$	o
condition	nn	o
,	,	o
but	cc	o
additionally	rb	o
it	prp	o
may	md	o
specify	vb	o
an	dt	o
init	nn	o
and	cc	o
a	dt	o
post	nn	o
statement	nn	o
,	,	o
such	jj	o
as	in	o
an	dt	o
assignment	nn	o
,	,	o
an	dt	o
increment	nn	o
or	cc	o
decrement	jj	o
statement	nn	o
.	.	o
The	dt	o
init	nn	o
statement	nn	o
may	md	o
be	vb	o
a	dt	o
short	jj	o
variable	nn	o
declaration	nn	o
,	,	o
but	cc	o
the	dt	o
post	nn	o
statement	nn	o
must	md	o
not	rb	o
.	.	o
Variables	nns	o
declared	vbn	o
by	in	o
the	dt	o
init	nn	o
statement	nn	o
are	vbp	o
re-used	jj	o
in	in	o
each	dt	o
iteration	nn	o
.	.	o
If	in	o
non-empty	jj	o
,	,	o
the	dt	o
init	nn	o
statement	nn	o
is	vbz	o
executed	vbn	o
once	rb	o
before	in	o
evaluating	vbg	o
the	dt	o
condition	nn	o
for	in	o
the	dt	o
first	jj	o
iteration	nn	o
;	:	o
the	dt	o
post	nn	o
statement	nn	o
is	vbz	o
executed	vbn	o
after	in	o
each	dt	o
execution	nn	o
of	in	o
the	dt	o
block	nn	o
(	(	o
and	cc	o
only	rb	o
if	in	o
the	dt	o
block	nn	o
was	vbd	o
executed	vbn	o
)	)	o
.	.	o
Any	dt	o
element	nn	o
of	in	o
the	dt	o
ForClause	nnp	o
may	md	o
be	vb	o
empty	jj	o
but	cc	o
the	dt	o
semicolons	nns	o
are	vbp	o
required	vbn	o
unless	in	o
there	ex	o
is	vbz	o
only	rb	o
a	dt	o
condition	nn	o
.	.	o
If	in	o
the	dt	o
condition	nn	o
is	vbz	o
absent	jj	o
,	,	o
it	prp	o
is	vbz	o
equivalent	jj	o
to	to	o
the	dt	o
boolean	jj	o
value	nn	o
.	.	o
For	in	o
statements	nns	o
with	in	o
clause	nn	o
A	dt	o
"	nn	o
for	in	o
"	nnp	o
statement	nn	o
with	in	o
a	dt	o
"	nnp	o
range	nn	o
"	nnp	o
clause	nn	o
iterates	vbz	o
through	in	o
all	pdt	o
entries	nns	o
of	in	o
an	dt	o
array	vb	o
,	,	o
slice	nn	o
,	,	o
string	vbg	o
or	cc	o
map	nn	o
,	,	o
or	cc	o
values	nns	o
received	jj	o
on	in	o
a	dt	o
channel	nn	o
.	.	o
For	in	o
each	dt	o
entry	nn	o
it	prp	o
assigns	vbz	o
iteration	nn	o
values	nns	o
to	to	o
corresponding	jj	o
iteration	nn	o
variables	nns	o
if	in	o
present	vb	o
and	cc	o
then	rb	o
executes	vbz	o
the	dt	o
block	nn	o
.	.	o
The	dt	o
expression	nn	o
on	in	o
the	dt	o
right	nn	o
in	in	o
the	dt	o
"	nnp	o
range	nn	o
"	nnp	o
clause	nn	o
is	vbz	o
called	vbd	o
the	dt	o
range	nn	o
expression	nn	o
,	,	o
its	prp$	o
core	nn	o
type	nn	o
must	md	o
be	vb	o
an	dt	o
array	vb	o
,	,	o
pointer	nn	o
to	to	o
an	dt	o
array	vb	o
,	,	o
slice	nn	o
,	,	o
string	nn	o
,	,	o
map	nn	o
,	,	o
or	cc	o
channel	nns	o
permitting	vbg	o
receive	nn	o
operations	nns	o
.	.	o
As	in	o
with	in	o
an	dt	o
assignment	nn	o
,	,	o
if	in	o
present	vb	o
the	dt	o
operands	nns	o
on	in	o
the	dt	o
left	nn	o
must	md	o
be	vb	o
addressable	jj	o
or	cc	o
map	nn	o
index	nn	o
expressions	nns	o
;	:	o
they	prp	o
denote	vbp	o
the	dt	o
iteration	nn	o
variables	nns	o
.	.	o
If	in	o
the	dt	o
range	nn	o
expression	nn	o
is	vbz	o
a	dt	o
channel	nn	o
,	,	o
at	in	o
most	jjs	o
one	nn	o
iteration	nn	o
variable	nn	o
is	vbz	o
permitted	vbn	o
,	,	o
otherwise	rb	o
there	ex	o
may	md	o
be	vb	o
up	in	o
to	to	o
two	cd	o
.	.	o
If	in	o
the	dt	o
last	jj	o
iteration	nn	o
variable	nn	o
is	vbz	o
the	dt	o
blank	jj	o
identifier	nn	o
,	,	o
the	dt	o
range	nn	o
clause	nn	o
is	vbz	o
equivalent	jj	o
to	to	o
the	dt	o
same	jj	o
clause	nn	o
without	in	o
that	wdt	o
identifier	nn	o
.	.	o
The	dt	o
range	nn	o
expression	nn	o
is	vbz	o
evaluated	vbn	o
once	rb	o
before	in	o
beginning	vbg	o
the	dt	o
loop	nn	o
,	,	o
with	in	o
one	nn	o
exception	nn	o
:	:	o
if	in	o
at	in	o
most	jjs	o
one	nn	o
iteration	nn	o
variable	nn	o
is	vbz	o
present	vb	o
and	cc	o
is	vbz	o
constant	nn	o
,	,	o
the	dt	o
range	nn	o
expression	nn	o
is	vbz	o
not	rb	o
evaluated	vbn	o
.	.	o
Function	nnp	b-person
calls	vbz	o
on	in	o
the	dt	o
left	nn	o
are	vbp	o
evaluated	vbn	o
once	rb	o
per	in	o
iteration	nn	o
.	.	o
For	in	o
each	dt	o
iteration	nn	o
,	,	o
iteration	nn	o
values	nns	o
are	vbp	o
produced	vbn	o
as	in	o
follows	vbz	o
if	in	o
the	dt	o
respective	jj	o
iteration	nn	o
variables	nns	o
are	vbp	o
present	jj	o
:	:	o
Range	nnp	o
expression	nn	o
1st	cd	o
value	nn	o
2nd	cd	o
value	nn	o
array	nn	o
or	cc	o
slice	nn	o
a	dt	o
[	nn	o
n]E	nn	o
,	,	o
*[n]E	nnp	b-gpe
,	,	o
or	cc	o
[	nnp	o
]E	nnp	o
index	nn	o
i	nn	o
int	nn	o
a[i	nn	o
]	nnp	o
E	nnp	o
string	vbg	o
s	jj	o
string	vbg	o
type	nn	o
index	nn	o
i	nn	o
int	nn	o
see	vbp	o
below	in	o
rune	nns	o
map	nn	o
m	nn	o
map[K]V	nn	o
key	nn	o
k	nn	o
K	nnp	o
m[k	nn	o
]	nn	o
V	nnp	o
channel	nns	o
c	nn	o
chan	vbp	o
E	nnp	o
,	,	o
<-chan	jj	o
E	nnp	o
element	nn	o
e	nn	o
E	nnp	o
For	in	o
an	dt	o
array	vb	o
,	,	o
pointer	nn	o
to	to	o
array	vb	o
,	,	o
or	cc	o
slice	nn	o
value	nn	o
,	,	o
the	dt	o
index	nn	o
iteration	nn	o
values	nns	o
are	vbp	o
produced	vbn	o
in	in	o
increasing	vbg	o
order	nn	o
,	,	o
starting	vbg	o
at	in	o
element	nn	o
index	nn	o
0	-none-	o
.	.	o
If	in	o
at	in	o
most	jjs	o
one	nn	o
iteration	nn	o
variable	nn	o
is	vbz	o
present	jj	o
,	,	o
the	dt	o
range	nn	o
loop	nn	o
produces	vbz	o
iteration	nn	o
values	nns	o
from	in	o
0	-none-	o
up	in	o
to	to	o
and	cc	o
does	vbz	o
not	rb	o
index	nn	o
into	in	o
the	dt	o
array	nn	o
or	cc	o
slice	nn	o
itself	prp	o
.	.	o
For	in	o
a	dt	o
slice	nn	o
,	,	o
the	dt	o
number	nn	o
of	in	o
iterations	nns	o
is	vbz	o
0	-none-	o
.	.	o
For	in	o
a	dt	o
string	vbg	o
value	nn	o
,	,	o
the	dt	o
"	nnp	o
range	nn	o
"	nnp	o
clause	nn	o
iterates	vbz	o
over	in	o
the	dt	o
Unicode	nnp	b-gpe
code	nn	o
points	nns	o
in	in	o
the	dt	o
string	vbg	o
starting	vbg	o
at	in	o
byte	nn	o
index	nn	o
0	-none-	o
.	.	o
On	in	o
successive	jj	o
iterations	nns	o
,	,	o
the	dt	o
index	nn	o
value	nn	o
will	md	o
be	vb	o
the	dt	o
index	nn	o
of	in	o
the	dt	o
first	jj	o
byte	nn	o
of	in	o
successive	jj	o
UTF-8-encoded	jj	o
code	nn	o
points	nns	o
in	in	o
the	dt	o
string	nn	o
,	,	o
and	cc	o
the	dt	o
second	jj	o
value	nn	o
,	,	o
of	in	o
type	nn	o
,	,	o
will	md	o
be	vb	o
the	dt	o
value	nn	o
of	in	o
the	dt	o
corresponding	jj	o
code	nn	o
point	nn	o
.	.	o
If	in	o
the	dt	o
iteration	nn	o
encounters	vbz	o
an	dt	o
invalid	jj	o
UTF-8	jj	o
sequence	nn	o
,	,	o
the	dt	o
second	jj	o
value	nn	o
will	md	o
be	vb	o
,	,	o
the	dt	o
Unicode	nnp	b-gpe
replacement	nn	o
character	nn	o
,	,	o
and	cc	o
the	dt	o
next	jj	o
iteration	nn	o
will	md	o
advance	vb	o
a	dt	o
single	jj	o
byte	nn	o
in	in	o
the	dt	o
string	nn	o
.	.	o
The	dt	o
iteration	nn	o
order	nn	o
over	in	o
maps	nns	o
is	vbz	o
not	rb	o
specified	vbn	o
and	cc	o
is	vbz	o
not	rb	o
guaranteed	vbn	o
to	to	o
be	vb	o
the	dt	o
same	jj	o
from	in	o
one	nn	o
iteration	nn	o
to	to	o
the	dt	o
next	jj	o
.	.	o
If	in	o
a	dt	o
map	nn	o
entry	nn	o
that	wdt	o
has	vbz	o
not	rb	o
yet	rb	o
been	vbn	o
reached	vbd	o
is	vbz	o
removed	vbn	o
during	in	o
iteration	nn	o
,	,	o
the	dt	o
corresponding	jj	o
iteration	nn	o
value	nn	o
will	md	o
not	rb	o
be	vb	o
produced	vbn	o
.	.	o
If	in	o
a	dt	o
map	nn	o
entry	nn	o
is	vbz	o
created	vbn	o
during	in	o
iteration	nn	o
,	,	o
that	wdt	o
entry	nn	o
may	md	o
be	vb	o
produced	vbn	o
during	in	o
the	dt	o
iteration	nn	o
or	cc	o
may	md	o
be	vb	o
skipped	vbn	o
.	.	o
The	dt	o
choice	nn	o
may	md	o
vary	vb	o
for	in	o
each	dt	o
entry	nn	o
created	vbn	o
and	cc	o
from	in	o
one	nn	o
iteration	nn	o
to	to	o
the	dt	o
next	jj	o
.	.	o
If	in	o
the	dt	o
map	nn	o
is	vbz	o
,	,	o
the	dt	o
number	nn	o
of	in	o
iterations	nns	o
is	vbz	o
0	-none-	o
.	.	o
For	in	o
channels	nns	o
,	,	o
the	dt	o
iteration	nn	o
values	nns	o
produced	vbn	o
are	vbp	o
the	dt	o
successive	jj	o
values	nns	o
sent	vbn	o
on	in	o
the	dt	o
channel	nns	o
until	in	o
the	dt	o
channel	nns	o
is	vbz	o
closed	vbn	o
.	.	o
If	in	o
the	dt	o
channel	nns	o
is	vbz	o
,	,	o
the	dt	o
range	nn	o
expression	nn	o
blocks	vbz	o
forever	rb	o
.	.	o
The	dt	o
iteration	nn	o
values	nns	o
are	vbp	o
assigned	vbn	o
to	to	o
the	dt	o
respective	jj	o
iteration	nn	o
variables	nns	o
as	in	o
in	in	o
an	dt	o
assignment	nn	o
statement	nn	o
.	.	o
The	dt	o
iteration	nn	o
variables	nns	o
may	md	o
be	vb	o
declared	vbn	o
by	in	o
the	dt	o
"	nnp	o
range	nn	o
"	nnp	o
clause	nn	o
using	vbg	o
a	dt	o
form	nn	o
of	in	o
short	jj	o
variable	nn	o
declaration	nn	o
(	(	o
)	)	o
.	.	o
In	in	o
this	dt	o
case	nn	o
their	prp$	o
types	nns	o
are	vbp	o
set	nn	o
to	to	o
the	dt	o
types	nns	o
of	in	o
the	dt	o
respective	jj	o
iteration	nn	o
values	nns	o
and	cc	o
their	prp$	o
scope	nn	o
is	vbz	o
the	dt	o
block	nn	o
of	in	o
the	dt	o
"	nn	o
for	in	o
"	nnp	o
statement	nn	o
;	:	o
they	prp	o
are	vbp	o
re-used	jj	o
in	in	o
each	dt	o
iteration	nn	o
.	.	o
If	in	o
the	dt	o
iteration	nn	o
variables	nns	o
are	vbp	o
declared	vbn	o
outside	in	o
the	dt	o
"	nn	o
for	in	o
"	nnp	o
statement	nn	o
,	,	o
after	in	o
execution	nn	o
their	prp$	o
values	nns	o
will	md	o
be	vb	o
those	dt	o
of	in	o
the	dt	o
last	jj	o
iteration	nn	o
.	.	o
Go	nnp	o
statements	nns	o
A	dt	o
"	nn	o
go	vbp	o
"	jj	o
statement	nn	o
starts	vbz	o
the	dt	o
execution	nn	o
of	in	o
a	dt	o
function	nn	o
call	nn	o
as	in	o
an	dt	o
independent	jj	o
concurrent	jj	o
thread	nn	o
of	in	o
control	nn	o
,	,	o
or	cc	o
goroutine	nn	o
,	,	o
within	in	o
the	dt	o
same	jj	o
address	nn	o
space	nn	o
.	.	o
The	dt	o
expression	nn	o
must	md	o
be	vb	o
a	dt	o
function	nn	o
or	cc	o
method	nn	o
call	nn	o
;	:	o
it	prp	o
cannot	vbp	o
be	vb	o
parenthesized	vbn	o
.	.	o
Calls	vbz	o
of	in	o
built-in	jj	o
functions	nns	o
are	vbp	o
restricted	vbn	o
as	in	o
for	in	o
expression	nn	o
statements	nns	o
.	.	o
The	dt	o
function	nn	o
value	nn	o
and	cc	o
parameters	nns	o
are	vbp	o
evaluated	vbn	o
as	in	o
usual	jj	o
in	in	o
the	dt	o
calling	vbg	o
goroutine	nn	o
,	,	o
but	cc	o
unlike	in	o
with	in	o
a	dt	o
regular	jj	o
call	nn	o
,	,	o
program	nn	o
execution	nn	o
does	vbz	o
not	rb	o
wait	vb	o
for	in	o
the	dt	o
invoked	vbn	o
function	nn	o
to	to	o
complete	vb	o
.	.	o
Instead	rb	o
,	,	o
the	dt	o
function	nn	o
begins	vbz	o
executing	vbg	o
independently	rb	o
in	in	o
a	dt	o
new	jj	o
goroutine	nn	o
.	.	o
When	wrb	o
the	dt	o
function	nn	o
terminates	vbz	o
,	,	o
its	prp$	o
goroutine	nn	o
also	rb	o
terminates	vbz	o
.	.	o
If	in	o
the	dt	o
function	nn	o
has	vbz	o
any	dt	o
return	vb	o
values	nns	o
,	,	o
they	prp	o
are	vbp	o
discarded	vbn	o
when	wrb	o
the	dt	o
function	nn	o
completes	vbz	o
.	.	o
Select	jj	o
statements	nns	o
A	dt	o
"	vb	o
select	jj	o
"	nnp	o
statement	nn	o
chooses	vbz	o
which	wdt	o
of	in	o
a	dt	o
set	nn	o
of	in	o
possible	jj	o
send	vb	o
or	cc	o
receive	nn	o
operations	nns	o
will	md	o
proceed	vb	o
.	.	o
It	prp	o
looks	vbz	o
similar	jj	o
to	to	o
a	dt	o
"	nnp	o
switch	nn	o
"	nnp	o
statement	nn	o
but	cc	o
with	in	o
the	dt	o
cases	nns	o
all	pdt	o
referring	vbg	o
to	to	o
communication	nn	o
operations	nns	o
.	.	o
A	dt	o
case	nn	o
with	in	o
a	dt	o
RecvStmt	nnp	o
may	md	o
assign	vb	o
the	dt	o
result	nn	o
of	in	o
a	dt	o
RecvExpr	nnp	b-gpe
to	to	o
one	nn	o
or	cc	o
two	cd	o
variables	nns	o
,	,	o
which	wdt	o
may	md	o
be	vb	o
declared	vbn	o
using	vbg	o
a	dt	o
short	jj	o
variable	nn	o
declaration	nn	o
.	.	o
The	dt	o
RecvExpr	nnp	b-gpe
must	md	o
be	vb	o
a	dt	o
(	(	o
possibly	rb	o
parenthesized	vbn	o
)	)	o
receive	nn	o
operation	nn	o
.	.	o
There	ex	o
can	md	o
be	vb	o
at	in	o
most	jjs	o
one	nn	o
default	nn	o
case	nn	o
and	cc	o
it	prp	o
may	md	o
appear	vbp	o
anywhere	rb	o
in	in	o
the	dt	o
list	nn	o
of	in	o
cases	nns	o
.	.	o
Execution	nn	o
of	in	o
a	dt	o
"	vb	o
select	jj	o
"	nnp	o
statement	nn	o
proceeds	nns	o
in	in	o
several	jj	o
steps	nns	o
:	:	o
For	in	o
all	pdt	o
the	dt	o
cases	nns	o
in	in	o
the	dt	o
statement	nn	o
,	,	o
the	dt	o
channel	nns	o
operands	nns	o
of	in	o
receive	nn	o
operations	nns	o
and	cc	o
the	dt	o
channel	nns	o
and	cc	o
right-hand-side	jj	o
expressions	nns	o
of	in	o
send	vb	o
statements	nns	o
are	vbp	o
evaluated	vbn	o
exactly	rb	o
once	rb	o
,	,	o
in	in	o
source	nn	o
order	nn	o
,	,	o
upon	in	o
entering	vbg	o
the	dt	o
"	vb	o
select	jj	o
"	nnp	o
statement	nn	o
.	.	o
The	dt	o
result	nn	o
is	vbz	o
a	dt	o
set	nn	o
of	in	o
channels	vb	o
to	to	o
receive	nn	o
from	in	o
or	cc	o
send	vb	o
to	to	o
,	,	o
and	cc	o
the	dt	o
corresponding	jj	o
values	nns	o
to	to	o
send	vb	o
.	.	o
Any	dt	o
side	nn	o
effects	nns	o
in	in	o
that	wdt	o
evaluation	nn	o
will	md	o
occur	vb	o
irrespective	nn	o
of	in	o
which	wdt	o
(	(	o
if	in	o
any	dt	o
)	)	o
communication	nn	o
operation	nn	o
is	vbz	o
selected	vbn	o
to	to	o
proceed	vb	o
.	.	o
Expressions	nns	o
on	in	o
the	dt	o
left-hand	jj	o
side	nn	o
of	in	o
a	dt	o
RecvStmt	nnp	o
with	in	o
a	dt	o
short	jj	o
variable	nn	o
declaration	nn	o
or	cc	o
assignment	nn	o
are	vbp	o
not	rb	o
yet	rb	o
evaluated	vbn	o
.	.	o
If	in	o
one	nn	o
or	cc	o
more	jjr	o
of	in	o
the	dt	o
communications	nns	o
can	md	o
proceed	vb	o
,	,	o
a	dt	o
single	jj	o
one	nn	o
that	wdt	o
can	md	o
proceed	vb	o
is	vbz	o
chosen	vbn	o
via	in	o
a	dt	o
uniform	jj	o
pseudo-random	jj	o
selection	nn	o
.	.	o
Otherwise	rb	o
,	,	o
if	in	o
there	ex	o
is	vbz	o
a	dt	o
default	nn	o
case	nn	o
,	,	o
that	wdt	o
case	nn	o
is	vbz	o
chosen	vbn	o
.	.	o
If	in	o
there	ex	o
is	vbz	o
no	dt	o
default	nn	o
case	nn	o
,	,	o
the	dt	o
"	vb	o
select	jj	o
"	nnp	o
statement	nn	o
blocks	vbz	o
until	in	o
at	in	o
least	jjs	o
one	nn	o
of	in	o
the	dt	o
communications	nns	o
can	md	o
proceed	vb	o
.	.	o
Unless	in	o
the	dt	o
selected	vbn	o
case	nn	o
is	vbz	o
the	dt	o
default	nn	o
case	nn	o
,	,	o
the	dt	o
respective	jj	o
communication	nn	o
operation	nn	o
is	vbz	o
executed	vbn	o
.	.	o
If	in	o
the	dt	o
selected	vbn	o
case	nn	o
is	vbz	o
a	dt	o
RecvStmt	nnp	o
with	in	o
a	dt	o
short	jj	o
variable	nn	o
declaration	nn	o
or	cc	o
an	dt	o
assignment	nn	o
,	,	o
the	dt	o
left-hand	jj	o
side	nn	o
expressions	nns	o
are	vbp	o
evaluated	vbn	o
and	cc	o
the	dt	o
received	jj	o
value	nn	o
(	(	o
or	cc	o
values	nns	o
)	)	o
are	vbp	o
assigned	vbn	o
.	.	o
The	dt	o
statement	nn	o
list	nn	o
of	in	o
the	dt	o
selected	vbn	o
case	nn	o
is	vbz	o
executed	vbn	o
.	.	o
Since	in	o
communication	nn	o
on	in	o
channels	vb	o
can	md	o
never	rb	o
proceed	vb	o
,	,	o
a	dt	o
select	nn	o
with	in	o
only	rb	o
channels	vb	o
and	cc	o
no	dt	o
default	nn	o
case	nn	o
blocks	vbz	o
forever	rb	o
.	.	o
Return	nnp	o
statements	nns	o
A	dt	o
"	jj	o
return	nn	o
"	nnp	o
statement	nn	o
in	in	o
a	dt	o
function	nn	o
terminates	nns	o
the	dt	o
execution	nn	o
of	in	o
,	,	o
and	cc	o
optionally	rb	o
provides	vbz	o
one	nn	o
or	cc	o
more	jjr	o
result	nn	o
values	nns	o
.	.	o
Any	dt	o
functions	nns	o
deferred	jj	o
by	in	o
are	vbp	o
executed	vbn	o
before	in	o
returns	nns	o
to	to	o
its	prp$	o
caller	nn	o
.	.	o
In	in	o
a	dt	o
function	nn	o
without	in	o
a	dt	o
result	nn	o
type	nn	o
,	,	o
a	dt	o
"	jj	o
return	nn	o
"	nnp	o
statement	nn	o
must	md	o
not	rb	o
specify	vb	o
any	dt	o
result	nn	o
values	nns	o
.	.	o
There	ex	o
are	vbp	o
three	cd	o
ways	nns	o
to	to	o
return	vb	o
values	nns	o
from	in	o
a	dt	o
function	nn	o
with	in	o
a	dt	o
result	nn	o
type	nn	o
:	:	o
The	dt	o
return	vb	o
value	nn	o
or	cc	o
values	nns	o
may	md	o
be	vb	o
explicitly	rb	o
listed	vbn	o
in	in	o
the	dt	o
"	jj	o
return	nn	o
"	nnp	o
statement	nn	o
.	.	o
Each	dt	o
expression	nn	o
must	md	o
be	vb	o
single-valued	jj	o
and	cc	o
assignable	jj	o
to	to	o
the	dt	o
corresponding	jj	o
element	nn	o
of	in	o
the	dt	o
function	nn	o
's	pos	o
result	nn	o
type	nn	o
.	.	o
The	dt	o
expression	nn	o
list	nn	o
in	in	o
the	dt	o
"	jj	o
return	nn	o
"	nnp	o
statement	nn	o
may	md	o
be	vb	o
a	dt	o
single	jj	o
call	nn	o
to	to	o
a	dt	o
multi-valued	jj	o
function	nn	o
.	.	o
The	dt	o
effect	nn	o
is	vbz	o
as	in	o
if	in	o
each	dt	o
value	nn	o
returned	vbn	o
from	in	o
that	wdt	o
function	nn	o
were	vbd	o
assigned	vbn	o
to	to	o
a	dt	o
temporary	jj	o
variable	nn	o
with	in	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
respective	jj	o
value	nn	o
,	,	o
followed	vbn	o
by	in	o
a	dt	o
"	jj	o
return	nn	o
"	nnp	o
statement	nn	o
listing	vbg	o
these	dt	o
variables	nns	o
,	,	o
at	in	o
which	wdt	o
point	nn	o
the	dt	o
rules	nns	o
of	in	o
the	dt	o
previous	jj	o
case	nn	o
apply	vb	o
.	.	o
The	dt	o
expression	nn	o
list	nn	o
may	md	o
be	vb	o
empty	jj	o
if	in	o
the	dt	o
function	nn	o
's	pos	o
result	nn	o
type	nn	o
specifies	vbz	o
names	vbz	o
for	in	o
its	prp$	o
result	nn	o
parameters	nns	o
.	.	o
The	dt	o
result	nn	o
parameters	nns	o
act	vbp	o
as	in	o
ordinary	jj	o
local	jj	o
variables	nns	o
and	cc	o
the	dt	o
function	nn	o
may	md	o
assign	vb	o
values	nns	o
to	to	o
them	prp	o
as	in	o
necessary	jj	o
.	.	o
The	dt	o
"	jj	o
return	nn	o
"	nnp	o
statement	nn	o
returns	nns	o
the	dt	o
values	nns	o
of	in	o
these	dt	o
variables	nns	o
.	.	o
Regardless	nnp	o
of	in	o
how	wrb	o
they	prp	o
are	vbp	o
declared	vbn	o
,	,	o
all	pdt	o
the	dt	o
result	nn	o
values	nns	o
are	vbp	o
initialized	vbn	o
to	to	o
the	dt	o
zero	nn	o
values	nns	o
for	in	o
their	prp$	o
type	nn	o
upon	in	o
entry	nn	o
to	to	o
the	dt	o
function	nn	o
.	.	o
A	dt	o
"	jj	o
return	nn	o
"	nnp	o
statement	nn	o
that	wdt	o
specifies	vbz	o
results	nns	o
sets	vbz	o
the	dt	o
result	nn	o
parameters	nns	o
before	in	o
any	dt	o
deferred	jj	o
functions	nns	o
are	vbp	o
executed	vbn	o
.	.	o
Implementation	nnp	o
restriction	nn	o
:	:	o
A	dt	o
compiler	nn	o
may	md	o
disallow	vb	o
an	dt	o
empty	jj	o
expression	nn	o
list	nn	o
in	in	o
a	dt	o
"	jj	o
return	nn	o
"	nnp	o
statement	nn	o
if	in	o
a	dt	o
different	jj	o
entity	nn	o
(	(	o
constant	jj	o
,	,	o
type	nn	o
,	,	o
or	cc	o
variable	jj	o
)	)	o
with	in	o
the	dt	o
same	jj	o
name	nn	o
as	in	o
a	dt	o
result	nn	o
parameter	nn	o
is	vbz	o
in	in	o
scope	nn	o
at	in	o
the	dt	o
place	nn	o
of	in	o
the	dt	o
return	nn	o
.	.	o
Break	nnp	o
statements	nns	o
A	dt	o
"	nnp	o
break	nn	o
"	nnp	o
statement	nn	o
terminates	nns	o
execution	nn	o
of	in	o
the	dt	o
innermost	nn	o
"	nn	o
for	in	o
"	nn	o
,	,	o
"	nnp	o
switch	nn	o
"	nn	o
,	,	o
or	cc	o
"	vb	o
select	jj	o
"	nnp	o
statement	nn	o
within	in	o
the	dt	o
same	jj	o
function	nn	o
.	.	o
If	in	o
there	ex	o
is	vbz	o
a	dt	o
label	nn	o
,	,	o
it	prp	o
must	md	o
be	vb	o
that	wdt	o
of	in	o
an	dt	o
enclosing	vbg	o
"	nn	o
for	in	o
"	nn	o
,	,	o
"	nnp	o
switch	nn	o
"	nn	o
,	,	o
or	cc	o
"	vb	o
select	jj	o
"	nnp	o
statement	nn	o
,	,	o
and	cc	o
that	wdt	o
is	vbz	o
the	dt	o
one	nn	o
whose	wp$	o
execution	nn	o
terminates	vbz	o
.	.	o
Continue	nnp	o
statements	nns	o
A	dt	o
"	nn	o
continue	nn	o
"	nnp	o
statement	nn	o
begins	vbz	o
the	dt	o
next	jj	o
iteration	nn	o
of	in	o
the	dt	o
innermost	nn	o
"	nn	o
for	in	o
"	nnp	o
loop	nn	o
at	in	o
its	prp$	o
post	nn	o
statement	nn	o
.	.	o
The	dt	o
"	nn	o
for	in	o
"	nnp	o
loop	nn	o
must	md	o
be	vb	o
within	in	o
the	dt	o
same	jj	o
function	nn	o
.	.	o
If	in	o
there	ex	o
is	vbz	o
a	dt	o
label	nn	o
,	,	o
it	prp	o
must	md	o
be	vb	o
that	wdt	o
of	in	o
an	dt	o
enclosing	vbg	o
"	nn	o
for	in	o
"	nnp	o
statement	nn	o
,	,	o
and	cc	o
that	wdt	o
is	vbz	o
the	dt	o
one	nn	o
whose	wp$	o
execution	nn	o
advances	nns	o
.	.	o
Goto	nnp	o
statements	nns	o
A	dt	o
"	jj	o
goto	nn	o
"	nnp	o
statement	nn	o
transfers	nns	o
control	vbp	o
to	to	o
the	dt	o
statement	nn	o
with	in	o
the	dt	o
corresponding	jj	o
label	nn	o
within	in	o
the	dt	o
same	jj	o
function	nn	o
.	.	o
Executing	vbg	o
the	dt	o
"	jj	o
goto	nn	o
"	nnp	o
statement	nn	o
must	md	o
not	rb	o
cause	vb	o
any	dt	o
variables	nns	o
to	to	o
come	vb	o
into	in	o
scope	nn	o
that	wdt	o
were	vbd	o
not	rb	o
already	rb	o
in	in	o
scope	nn	o
at	in	o
the	dt	o
point	nn	o
of	in	o
the	dt	o
goto	nn	o
.	.	o
For	in	o
instance	nn	o
,	,	o
this	dt	o
example	nn	o
:	:	o
is	vbz	o
erroneous	jj	o
because	in	o
the	dt	o
jump	nn	o
to	to	o
label	nn	o
skips	pdt	o
the	dt	o
creation	nn	o
of	in	o
.	.	o
A	dt	o
"	jj	o
goto	nn	o
"	nnp	o
statement	nn	o
outside	in	o
a	dt	o
block	nn	o
cannot	vbp	o
jump	nn	o
to	to	o
a	dt	o
label	nn	o
inside	in	o
that	wdt	o
block	nn	o
.	.	o
For	in	o
instance	nn	o
,	,	o
this	dt	o
example	nn	o
:	:	o
is	vbz	o
erroneous	jj	o
because	in	o
the	dt	o
label	nn	o
is	vbz	o
inside	in	o
the	dt	o
"	nn	o
for	in	o
"	nnp	o
statement	nn	o
's	pos	o
block	nn	o
but	cc	o
the	dt	o
is	vbz	o
not	rb	o
.	.	o
Fallthrough	in	o
statements	nns	o
A	dt	o
"	nnp	o
fallthrough	in	o
"	nnp	o
statement	nn	o
transfers	nns	o
control	vbp	o
to	to	o
the	dt	o
first	jj	o
statement	nn	o
of	in	o
the	dt	o
next	jj	o
case	nn	o
clause	nn	o
in	in	o
an	dt	o
expression	nn	o
"	nnp	o
switch	nn	o
"	nnp	o
statement	nn	o
.	.	o
It	prp	o
may	md	o
be	vb	o
used	vbn	o
only	rb	o
as	in	o
the	dt	o
final	jj	o
non-empty	jj	o
statement	nn	o
in	in	o
such	jj	o
a	dt	o
clause	nn	o
.	.	o
Defer	nnp	o
statements	nns	o
A	dt	o
"	nnp	o
defer	nn	o
"	nnp	o
statement	nn	o
invokes	vbz	o
a	dt	o
function	nn	o
whose	wp$	o
execution	nn	o
is	vbz	o
deferred	jj	o
to	to	o
the	dt	o
moment	nn	o
the	dt	o
surrounding	vbg	o
function	nn	o
returns	nns	o
,	,	o
either	dt	o
because	in	o
the	dt	o
surrounding	vbg	o
function	nn	o
executed	vbn	o
a	dt	o
return	vb	o
statement	nn	o
,	,	o
reached	vbd	o
the	dt	o
end	nn	o
of	in	o
its	prp$	o
function	nn	o
body	nn	o
,	,	o
or	cc	o
because	in	o
the	dt	o
corresponding	jj	o
goroutine	nn	o
is	vbz	o
panicking	nn	o
.	.	o
The	dt	o
expression	nn	o
must	md	o
be	vb	o
a	dt	o
function	nn	o
or	cc	o
method	nn	o
call	nn	o
;	:	o
it	prp	o
cannot	vbp	o
be	vb	o
parenthesized	vbn	o
.	.	o
Calls	vbz	o
of	in	o
built-in	jj	o
functions	nns	o
are	vbp	o
restricted	vbn	o
as	in	o
for	in	o
expression	nn	o
statements	nns	o
.	.	o
Each	dt	o
time	nn	o
a	dt	o
"	nnp	o
defer	nn	o
"	nnp	o
statement	nn	o
executes	nns	o
,	,	o
the	dt	o
function	nn	o
value	nn	o
and	cc	o
parameters	nns	o
to	to	o
the	dt	o
call	nn	o
are	vbp	o
evaluated	vbn	o
as	in	o
usual	jj	o
and	cc	o
saved	vbd	o
anew	rb	o
but	cc	o
the	dt	o
actual	jj	o
function	nn	o
is	vbz	o
not	rb	o
invoked	vbn	o
.	.	o
Instead	rb	o
,	,	o
deferred	jj	o
functions	nns	o
are	vbp	o
invoked	vbn	o
immediately	rb	o
before	in	o
the	dt	o
surrounding	vbg	o
function	nn	o
returns	nns	o
,	,	o
in	in	o
the	dt	o
reverse	nn	o
order	nn	o
they	prp	o
were	vbd	o
deferred	vbn	o
.	.	o
That	dt	o
is	vbz	o
,	,	o
if	in	o
the	dt	o
surrounding	vbg	o
function	nn	o
returns	nns	o
through	in	o
an	dt	o
explicit	jj	o
return	vb	o
statement	nn	o
,	,	o
deferred	jj	o
functions	nns	o
are	vbp	o
executed	vbn	o
after	in	o
any	dt	o
result	nn	o
parameters	nns	o
are	vbp	o
set	nn	o
by	in	o
that	wdt	o
return	vb	o
statement	nn	o
but	cc	o
before	in	o
the	dt	o
function	nn	o
returns	nns	o
to	to	o
its	prp$	o
caller	nn	o
.	.	o
If	in	o
a	dt	o
deferred	jj	o
function	nn	o
value	nn	o
evaluates	vbz	o
to	to	o
,	,	o
execution	nn	o
panics	nns	o
when	wrb	o
the	dt	o
function	nn	o
is	vbz	o
invoked	vbn	o
,	,	o
not	rb	o
when	wrb	o
the	dt	o
"	nnp	o
defer	nn	o
"	nnp	o
statement	nn	o
is	vbz	o
executed	vbn	o
.	.	o
For	in	o
instance	nn	o
,	,	o
if	in	o
the	dt	o
deferred	jj	o
function	nn	o
is	vbz	o
a	dt	o
function	nn	o
literal	nn	o
and	cc	o
the	dt	o
surrounding	vbg	o
function	nn	o
has	vbz	o
named	vbn	o
result	nn	o
parameters	nns	o
that	wdt	o
are	vbp	o
in	in	o
scope	nn	o
within	in	o
the	dt	o
literal	jj	o
,	,	o
the	dt	o
deferred	jj	o
function	nn	o
may	md	o
access	nn	o
and	cc	o
modify	vb	o
the	dt	o
result	nn	o
parameters	nns	o
before	in	o
they	prp	o
are	vbp	o
returned	vbn	o
.	.	o
If	in	o
the	dt	o
deferred	jj	o
function	nn	o
has	vbz	o
any	dt	o
return	vb	o
values	nns	o
,	,	o
they	prp	o
are	vbp	o
discarded	vbn	o
when	wrb	o
the	dt	o
function	nn	o
completes	vbz	o
.	.	o
(	(	o
See	nnp	b-person
also	rb	o
the	dt	o
section	nn	o
on	in	o
handling	vbg	o
panics	nns	o
.	.	o
)	)	o
Built-in	jj	o
functions	nns	o
Built-in	jj	o
functions	nns	o
are	vbp	o
predeclared	vbn	o
.	.	o
They	prp	o
are	vbp	o
called	vbd	o
like	in	o
any	dt	o
other	jj	o
function	nn	o
but	cc	o
some	dt	o
of	in	o
them	prp	o
accept	vb	o
a	dt	o
type	nn	o
instead	rb	o
of	in	o
an	dt	o
expression	nn	o
as	in	o
the	dt	o
first	jj	o
argument	nn	o
.	.	o
The	dt	o
built-in	jj	o
functions	nns	o
do	vbp	o
not	rb	o
have	vb	o
standard	vbn	o
Go	nnp	o
types	nns	o
,	,	o
so	rb	o
they	prp	o
can	md	o
only	rb	o
appear	vbp	o
in	in	o
call	nn	o
expressions	nns	o
;	:	o
they	prp	o
cannot	vbp	o
be	vb	o
used	vbn	o
as	in	o
function	nn	o
values	nns	o
.	.	o
Close	nnp	o
For	in	o
an	dt	o
argument	nn	o
with	in	o
a	dt	o
core	nn	o
type	nn	o
that	wdt	o
is	vbz	o
a	dt	o
channel	nn	o
,	,	o
the	dt	o
built-in	jj	o
function	nn	o
records	nns	o
that	wdt	o
no	dt	o
more	jjr	o
values	nns	o
will	md	o
be	vb	o
sent	vbn	o
on	in	o
the	dt	o
channel	nn	o
.	.	o
It	prp	o
is	vbz	o
an	dt	o
error	nn	o
if	in	o
is	vbz	o
a	dt	o
receive-only	jj	o
channel	nn	o
.	.	o
Sending	vbg	o
to	to	o
or	cc	o
closing	vbg	o
a	dt	o
closed	jj	o
channel	nns	o
causes	vbz	o
a	dt	o
run-time	jj	o
panic	nn	o
.	.	o
Closing	vbg	o
the	dt	o
nil	jj	o
channel	nns	o
also	rb	o
causes	vbz	o
a	dt	o
run-time	jj	o
panic	nn	o
.	.	o
After	in	o
calling	vbg	o
,	,	o
and	cc	o
after	in	o
any	dt	o
previously	rb	o
sent	vbn	o
values	nns	o
have	vb	o
been	vbn	o
received	vbn	o
,	,	o
receive	nn	o
operations	nns	o
will	md	o
return	vb	o
the	dt	o
zero	nn	o
value	nn	o
for	in	o
the	dt	o
channel	nn	o
's	pos	o
type	nn	o
without	in	o
blocking	vbg	o
.	.	o
The	dt	o
multi-valued	jj	o
receive	nn	o
operation	nn	o
returns	nns	o
a	dt	o
received	jj	o
value	nn	o
along	in	o
with	in	o
an	dt	o
indication	nn	o
of	in	o
whether	in	o
the	dt	o
channel	nns	o
is	vbz	o
closed	vbn	o
.	.	o
Length	nnp	b-person
and	cc	o
capacity	nn	o
The	dt	o
built-in	jj	o
functions	nns	o
and	cc	o
take	vb	o
arguments	nns	o
of	in	o
various	jj	o
types	nns	o
and	cc	o
return	vb	o
a	dt	o
result	nn	o
of	in	o
type	nn	o
.	.	o
The	dt	o
implementation	nn	o
guarantees	nns	o
that	wdt	o
the	dt	o
result	nn	o
always	rb	o
fits	vbz	o
into	in	o
an	dt	o
.	.	o
Call	vb	o
Argument	nnp	o
type	nn	o
Result	nnp	b-gpe
len(s	nn	o
)	)	o
string	vbg	o
type	nn	o
string	vbg	o
length	nn	o
in	in	o
bytes	nns	o
[	nn	o
n]T	nn	o
,	,	o
*[n]T	jj	b-gpe
array	nn	o
length	nn	o
(	(	o
==	nnp	o
n	rb	o
)	)	o
[	fw	o
]T	jj	o
slice	nn	o
length	nn	o
map[K]T	nn	o
map	nn	o
length	nn	o
(	(	o
number	nn	o
of	in	o
defined	vbn	o
keys	nns	o
)	)	o
chan	vbp	o
T	nnp	o
number	nn	o
of	in	o
elements	nns	o
queued	vbn	o
in	in	o
channel	nns	o
buffer	nn	o
type	nn	o
parameter	nn	o
see	vbp	o
below	in	o
cap(s	nn	o
)	)	o
[	nn	o
n]T	nn	o
,	,	o
*[n]T	jj	b-gpe
array	nn	o
length	nn	o
(	(	o
==	nnp	o
n	rb	o
)	)	o
[	fw	o
]T	jj	o
slice	nn	o
capacity	nn	o
chan	vbp	o
T	nnp	o
channel	nns	o
buffer	nn	o
capacity	nn	o
type	nn	o
parameter	nn	o
see	vbp	o
below	in	o
If	in	o
the	dt	o
argument	nn	o
type	nn	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
must	md	o
have	vb	o
specific	jj	o
types	nns	o
,	,	o
and	cc	o
the	dt	o
call	nn	o
(	(	o
or	cc	o
respectively	rb	o
)	)	o
must	md	o
be	vb	o
valid	jj	o
for	in	o
each	dt	o
specific	jj	o
type	nn	o
of	in	o
.	.	o
The	dt	o
result	nn	o
is	vbz	o
the	dt	o
length	nn	o
(	(	o
or	cc	o
capacity	nn	o
,	,	o
respectively	rb	o
)	)	o
of	in	o
the	dt	o
argument	nn	o
whose	wp$	o
type	nn	o
corresponds	vbz	o
to	to	o
the	dt	o
type	nn	o
argument	nn	o
with	in	o
which	wdt	o
was	vbd	o
instantiated	vbn	o
.	.	o
The	dt	o
capacity	nn	o
of	in	o
a	dt	o
slice	nn	o
is	vbz	o
the	dt	o
number	nn	o
of	in	o
elements	nns	o
for	in	o
which	wdt	o
there	ex	o
is	vbz	o
space	nn	o
allocated	vbn	o
in	in	o
the	dt	o
underlying	jj	o
array	nn	o
.	.	o
At	in	o
any	dt	o
time	nn	o
the	dt	o
following	vbg	o
relationship	nn	o
holds	vbz	o
:	:	o
The	dt	o
length	nn	o
of	in	o
a	dt	o
slice	nn	o
,	,	o
map	nn	o
or	cc	o
channel	nns	o
is	vbz	o
0	-none-	o
.	.	o
The	dt	o
capacity	nn	o
of	in	o
a	dt	o
slice	nn	o
or	cc	o
channel	nns	o
is	vbz	o
0	-none-	o
.	.	o
The	dt	o
expression	nn	o
is	vbz	o
constant	nn	o
if	in	o
is	vbz	o
a	dt	o
string	vbg	o
constant	nn	o
.	.	o
The	dt	o
expressions	nns	o
and	cc	o
are	vbp	o
constants	nns	o
if	in	o
the	dt	o
type	nn	o
of	in	o
is	vbz	o
an	dt	o
array	nn	o
or	cc	o
pointer	nn	o
to	to	o
an	dt	o
array	nn	o
and	cc	o
the	dt	o
expression	nn	o
does	vbz	o
not	rb	o
contain	vb	o
channel	nns	o
receives	nns	o
or	cc	o
(	(	o
non-constant	jj	o
)	)	o
function	nn	o
calls	vbz	o
;	:	o
in	in	o
this	dt	o
case	nn	o
is	vbz	o
not	rb	o
evaluated	vbn	o
.	.	o
Otherwise	rb	o
,	,	o
invocations	nns	o
of	in	o
and	cc	o
are	vbp	o
not	rb	o
constant	nn	o
and	cc	o
is	vbz	o
evaluated	vbn	o
.	.	o
Allocation	nnp	o
The	dt	o
built-in	jj	o
function	nn	o
takes	vbz	o
a	dt	o
type	nn	o
,	,	o
allocates	vbz	o
storage	nn	o
for	in	o
a	dt	o
variable	nn	o
of	in	o
that	wdt	o
type	nn	o
at	in	o
run	jj	o
time	nn	o
,	,	o
and	cc	o
returns	nns	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
pointing	vbg	o
to	to	o
it	prp	o
.	.	o
The	dt	o
variable	nn	o
is	vbz	o
initialized	vbn	o
as	in	o
described	vbn	o
in	in	o
the	dt	o
section	nn	o
on	in	o
initial	jj	o
values	nns	o
.	.	o
new(T	nn	o
)	)	o
For	in	o
instance	nn	o
allocates	vbz	o
storage	nn	o
for	in	o
a	dt	o
variable	nn	o
of	in	o
type	nn	o
,	,	o
initializes	vbz	o
it	prp	o
(	(	o
,	,	o
)	)	o
,	,	o
and	cc	o
returns	nns	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
containing	vbg	o
the	dt	o
address	nn	o
of	in	o
the	dt	o
location	nn	o
.	.	o
Making	vbg	o
slices	nns	o
,	,	o
maps	nns	o
and	cc	o
channels	vb	o
The	dt	o
built-in	jj	o
function	nn	o
takes	vbz	o
a	dt	o
type	nn	o
,	,	o
optionally	rb	o
followed	vbn	o
by	in	o
a	dt	o
type-specific	jj	o
list	nn	o
of	in	o
expressions	nns	o
.	.	o
The	dt	o
core	nn	o
type	nn	o
of	in	o
must	md	o
be	vb	o
a	dt	o
slice	nn	o
,	,	o
map	nn	o
or	cc	o
channel	nn	o
.	.	o
It	prp	o
returns	nns	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
(	(	o
not	rb	o
)	)	o
.	.	o
The	dt	o
memory	nn	o
is	vbz	o
initialized	vbn	o
as	in	o
described	vbn	o
in	in	o
the	dt	o
section	nn	o
on	in	o
initial	jj	o
values	nns	o
.	.	o
Call	vb	o
Core	nnp	b-gpe
type	nn	o
Result	nnp	b-gpe
make(T	nn	o
,	,	o
n	rb	o
)	)	o
slice	nn	o
slice	nn	o
of	in	o
type	nn	o
T	nnp	o
with	in	o
length	nn	o
n	in	o
and	cc	o
capacity	nn	o
n	in	o
make(T	nn	o
,	,	o
n	rb	o
,	,	o
m	nn	o
)	)	o
slice	nn	o
slice	nn	o
of	in	o
type	nn	o
T	nnp	o
with	in	o
length	nn	o
n	in	o
and	cc	o
capacity	nn	o
m	nn	o
make(T	nn	o
)	)	o
map	nn	o
map	nn	o
of	in	o
type	nn	o
T	nnp	o
make(T	nn	o
,	,	o
n	rb	o
)	)	o
map	nn	o
map	nn	o
of	in	o
type	nn	o
T	nnp	o
with	in	o
initial	jj	o
space	nn	o
for	in	o
approximately	rb	o
n	in	o
elements	nns	o
make(T	nn	o
)	)	o
channel	nns	o
unbuffered	jj	o
channel	nns	o
of	in	o
type	nn	o
T	nnp	o
make(T	nn	o
,	,	o
n	rb	o
)	)	o
channel	nns	o
buffered	vbd	o
channel	nns	o
of	in	o
type	nn	o
T	nnp	o
,	,	o
buffer	nn	o
size	nn	o
n	in	o
Each	dt	o
of	in	o
the	dt	o
size	nn	o
arguments	nns	o
and	cc	o
must	md	o
be	vb	o
of	in	o
integer	jj	o
type	nn	o
or	cc	o
an	dt	o
untyped	jj	o
constant	nn	o
.	.	o
A	dt	o
constant	nn	o
size	nn	o
argument	nn	o
must	md	o
be	vb	o
non-negative	jj	o
and	cc	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
;	:	o
if	in	o
it	prp	o
is	vbz	o
an	dt	o
untyped	jj	o
constant	nn	o
it	prp	o
is	vbz	o
given	vbn	o
type	nn	o
.	.	o
If	in	o
both	dt	o
and	cc	o
are	vbp	o
provided	vbn	o
and	cc	o
are	vbp	o
constant	nn	o
,	,	o
then	rb	o
must	md	o
be	vb	o
no	dt	o
larger	jjr	o
than	in	o
.	.	o
If	in	o
is	vbz	o
negative	jj	o
or	cc	o
larger	jjr	o
than	in	o
at	in	o
run	jj	o
time	nn	o
,	,	o
a	dt	o
run-time	jj	o
panic	nn	o
occurs	nns	o
.	.	o
Calling	vbg	o
with	in	o
a	dt	o
map	nn	o
type	nn	o
and	cc	o
size	nn	o
hint	nn	o
will	md	o
create	vb	o
a	dt	o
map	nn	o
with	in	o
initial	jj	o
space	nn	o
to	to	o
hold	vb	o
map	nn	o
elements	nns	o
.	.	o
The	dt	o
precise	jj	o
behavior	nn	o
is	vbz	o
implementation-dependent	jj	o
.	.	o
Appending	vbg	o
to	to	o
and	cc	o
copying	vbg	o
slices	nns	o
The	dt	o
built-in	jj	o
functions	nns	o
and	cc	o
assist	vb	o
in	in	o
common	jj	o
slice	nn	o
operations	nns	o
.	.	o
For	in	o
both	dt	o
functions	nns	o
,	,	o
the	dt	o
result	nn	o
is	vbz	o
independent	jj	o
of	in	o
whether	in	o
the	dt	o
memory	nn	o
referenced	vbn	o
by	in	o
the	dt	o
arguments	nns	o
overlaps	vbp	o
.	.	o
The	dt	o
variadic	jj	o
function	nn	o
appends	vbz	o
zero	nn	o
or	cc	o
more	jjr	o
values	nns	o
to	to	o
a	dt	o
slice	nn	o
and	cc	o
returns	nns	o
the	dt	o
resulting	vbg	o
slice	nn	o
.	.	o
The	dt	o
core	nn	o
type	nn	o
of	in	o
must	md	o
be	vb	o
a	dt	o
slice	nn	o
of	in	o
the	dt	o
form	nn	o
.	.	o
The	dt	o
values	nns	o
are	vbp	o
passed	vbd	o
to	to	o
a	dt	o
parameter	nn	o
of	in	o
type	nn	o
and	cc	o
the	dt	o
respective	jj	o
parameter	nn	o
passing	nn	o
rules	nns	o
apply	vb	o
.	.	o
As	in	o
a	dt	o
special	jj	o
case	nn	o
,	,	o
if	in	o
the	dt	o
core	nn	o
type	nn	o
of	in	o
is	vbz	o
,	,	o
also	rb	o
accepts	vbz	o
a	dt	o
second	jj	o
argument	nn	o
with	in	o
core	nn	o
type	nn	o
followed	vbn	o
by	in	o
.	.	o
This	dt	o
form	nn	o
appends	vbz	o
the	dt	o
bytes	nns	o
of	in	o
the	dt	o
string	nn	o
.	.	o
append(s	jj	o
S	nnp	o
,	,	o
x	nnp	o
...E	nn	o
)	)	o
S	nnp	o
//	nnp	o
E	nnp	o
is	vbz	o
the	dt	o
element	nn	o
type	nn	o
of	in	o
the	dt	o
core	nn	o
type	nn	o
of	in	o
S	nnp	o
If	in	o
the	dt	o
capacity	nn	o
of	in	o
is	vbz	o
not	rb	o
large	jj	o
enough	rb	o
to	to	o
fit	vb	o
the	dt	o
additional	jj	o
values	nns	o
,	,	o
allocates	vbz	o
a	dt	o
new	jj	o
,	,	o
sufficiently	rb	o
large	jj	o
underlying	jj	o
array	nn	o
that	wdt	o
fits	vbz	o
both	dt	o
the	dt	o
existing	vbg	o
slice	nn	o
elements	nns	o
and	cc	o
the	dt	o
additional	jj	o
values	nns	o
.	.	o
Otherwise	rb	o
,	,	o
re-uses	vbz	o
the	dt	o
underlying	jj	o
array	nn	o
.	.	o
The	dt	o
function	nn	o
copies	vbz	o
slice	nn	o
elements	nns	o
from	in	o
a	dt	o
source	nn	o
to	to	o
a	dt	o
destination	nn	o
and	cc	o
returns	nns	o
the	dt	o
number	nn	o
of	in	o
elements	nns	o
copied	vbn	o
.	.	o
The	dt	o
core	nn	o
types	nns	o
of	in	o
both	dt	o
arguments	nns	o
must	md	o
be	vb	o
slices	nns	o
with	in	o
identical	jj	o
element	nn	o
type	nn	o
.	.	o
The	dt	o
number	nn	o
of	in	o
elements	nns	o
copied	vbn	o
is	vbz	o
the	dt	o
minimum	nn	o
of	in	o
and	cc	o
.	.	o
As	in	o
a	dt	o
special	jj	o
case	nn	o
,	,	o
if	in	o
the	dt	o
destination	nn	o
's	pos	o
core	nn	o
type	nn	o
is	vbz	o
,	,	o
also	rb	o
accepts	vbz	o
a	dt	o
source	nn	o
argument	nn	o
with	in	o
core	nn	o
type	nn	o
.	.	o
This	dt	o
form	nn	o
copies	vbz	o
the	dt	o
bytes	nns	o
from	in	o
the	dt	o
string	vbg	o
into	in	o
the	dt	o
byte	nn	o
slice	nn	o
.	.	o
copy(dst	nn	o
,	,	o
src	rb	o
[	nnp	o
]T	nnp	o
)	)	o
int	nn	o
copy(dst	nn	o
[	nnp	o
]byte	nnp	o
,	,	o
src	rb	o
string	vbg	o
)	)	o
int	nn	o
Examples	nns	o
:	:	o
Deletion	nn	o
of	in	o
map	nn	o
elements	nns	o
The	dt	o
built-in	jj	o
function	nn	o
removes	vbz	o
the	dt	o
element	nn	o
with	in	o
key	nn	o
from	in	o
a	dt	o
map	nn	o
.	.	o
The	dt	o
value	nn	o
must	md	o
be	vb	o
assignable	jj	o
to	to	o
the	dt	o
key	nn	o
type	nn	o
of	in	o
.	.	o
delete(m	nn	o
,	,	o
k	nn	o
)	)	o
//	nnp	o
remove	jj	o
element	nn	o
m[k	nn	o
]	nn	o
from	in	o
map	nn	o
m	nn	o
If	in	o
the	dt	o
type	nn	o
of	in	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
it	prp	o
must	md	o
have	vb	o
specific	jj	o
types	nns	o
,	,	o
all	pdt	o
specific	jj	o
types	nns	o
must	md	o
be	vb	o
maps	nns	o
,	,	o
and	cc	o
they	prp	o
must	md	o
all	pdt	o
have	vb	o
identical	jj	o
key	nn	o
types	nns	o
.	.	o
If	in	o
the	dt	o
map	nn	o
is	vbz	o
or	cc	o
the	dt	o
element	nn	o
does	vbz	o
not	rb	o
exist	vb	o
,	,	o
is	vbz	o
a	dt	o
no-op	jj	o
.	.	o
Manipulating	vbg	o
complex	jj	o
numbers	nns	o
[	in	o
We	prp	o
do	vbp	o
n't	rb	o
support	vb	o
generic	jj	o
arguments	nns	o
for	in	o
these	dt	o
built-ins	nns	o
for	in	o
Go	nnp	o
1.18	nn	o
.	.	o
]	jj	o
Three	cd	o
functions	nns	o
assemble	jj	o
and	cc	o
disassemble	jj	o
complex	jj	o
numbers	nns	o
.	.	o
The	dt	o
built-in	jj	o
function	nn	o
constructs	vbz	o
a	dt	o
complex	jj	o
value	nn	o
from	in	o
a	dt	o
floating-point	nn	o
real	jj	o
and	cc	o
imaginary	jj	o
part	nn	o
,	,	o
while	in	o
and	cc	o
extract	vb	o
the	dt	o
real	jj	o
and	cc	o
imaginary	jj	o
parts	nns	o
of	in	o
a	dt	o
complex	jj	o
value	nn	o
.	.	o
complex(realPart	nn	o
,	,	o
imaginaryPart	vb	o
floatT	nn	o
)	)	o
complexT	nn	b-organization
real(complexT	nn	b-organization
)	)	o
floatT	vbz	o
imag(complexT	nn	o
)	)	o
floatT	vbz	o
The	dt	o
type	nn	o
of	in	o
the	dt	o
arguments	nns	o
and	cc	o
return	vb	o
value	nn	o
correspond	nn	o
.	.	o
For	in	o
,	,	o
the	dt	o
two	cd	o
arguments	nns	o
must	md	o
be	vb	o
of	in	o
the	dt	o
same	jj	o
floating-point	nn	o
type	nn	o
and	cc	o
the	dt	o
return	vb	o
type	nn	o
is	vbz	o
the	dt	o
complex	jj	o
type	nn	o
with	in	o
the	dt	o
corresponding	jj	o
floating-point	nn	o
constituents	nns	o
:	:	o
for	in	o
arguments	nns	o
,	,	o
and	cc	o
for	in	o
arguments	nns	o
.	.	o
If	in	o
one	nn	o
of	in	o
the	dt	o
arguments	nns	o
evaluates	vbz	o
to	to	o
an	dt	o
untyped	jj	o
constant	nn	o
,	,	o
it	prp	o
is	vbz	o
first	jj	o
implicitly	rb	o
converted	vbn	o
to	to	o
the	dt	o
type	nn	o
of	in	o
the	dt	o
other	jj	o
argument	nn	o
.	.	o
If	in	o
both	dt	o
arguments	nns	o
evaluate	vbp	o
to	to	o
untyped	jj	o
constants	nns	o
,	,	o
they	prp	o
must	md	o
be	vb	o
non-complex	jj	o
numbers	nns	o
or	cc	o
their	prp$	o
imaginary	jj	o
parts	nns	o
must	md	o
be	vb	o
zero	cd	o
,	,	o
and	cc	o
the	dt	o
return	vb	o
value	nn	o
of	in	o
the	dt	o
function	nn	o
is	vbz	o
an	dt	o
untyped	jj	o
complex	jj	o
constant	nn	o
.	.	o
For	in	o
and	cc	o
,	,	o
the	dt	o
argument	nn	o
must	md	o
be	vb	o
of	in	o
complex	jj	o
type	nn	o
,	,	o
and	cc	o
the	dt	o
return	vb	o
type	nn	o
is	vbz	o
the	dt	o
corresponding	jj	o
floating-point	nn	o
type	nn	o
:	:	o
for	in	o
a	dt	o
argument	nn	o
,	,	o
and	cc	o
for	in	o
a	dt	o
argument	nn	o
.	.	o
If	in	o
the	dt	o
argument	nn	o
evaluates	vbz	o
to	to	o
an	dt	o
untyped	jj	o
constant	nn	o
,	,	o
it	prp	o
must	md	o
be	vb	o
a	dt	o
number	nn	o
,	,	o
and	cc	o
the	dt	o
return	vb	o
value	nn	o
of	in	o
the	dt	o
function	nn	o
is	vbz	o
an	dt	o
untyped	jj	o
floating-point	nn	o
constant	nn	o
.	.	o
The	dt	o
and	cc	o
functions	nns	o
together	rb	o
form	nn	o
the	dt	o
inverse	nn	o
of	in	o
,	,	o
so	rb	o
for	in	o
a	dt	o
value	nn	o
of	in	o
a	dt	o
complex	jj	o
type	nn	o
,	,	o
.	.	o
If	in	o
the	dt	o
operands	nns	o
of	in	o
these	dt	o
functions	nns	o
are	vbp	o
all	pdt	o
constants	nns	o
,	,	o
the	dt	o
return	vb	o
value	nn	o
is	vbz	o
a	dt	o
constant	nn	o
.	.	o
Handling	vbg	o
panics	nns	o
Two	cd	o
built-in	jj	o
functions	nns	o
,	,	o
and	cc	o
,	,	o
assist	vb	o
in	in	o
reporting	nn	o
and	cc	o
handling	vbg	o
run-time	jj	o
panics	nns	o
and	cc	o
program-defined	jj	o
error	nn	o
conditions	nns	o
.	.	o
func	nn	o
panic(interface{}	nn	o
)	)	o
func	nn	o
recover(	nn	o
)	)	o
interface{}	nn	o
While	in	o
executing	vbg	o
a	dt	o
function	nn	o
,	,	o
an	dt	o
explicit	jj	o
call	nn	o
to	to	o
or	cc	o
a	dt	o
run-time	jj	o
panic	nn	o
terminates	nns	o
the	dt	o
execution	nn	o
of	in	o
.	.	o
Any	dt	o
functions	nns	o
deferred	jj	o
by	in	o
are	vbp	o
then	rb	o
executed	vbn	o
as	in	o
usual	jj	o
.	.	o
Next	jj	o
,	,	o
any	dt	o
deferred	jj	o
functions	nns	o
run	jj	o
by	in	o
caller	nn	o
are	vbp	o
run	vbn	o
,	,	o
and	cc	o
so	rb	o
on	in	o
up	in	o
to	to	o
any	dt	o
deferred	jj	o
by	in	o
the	dt	o
top-level	jj	o
function	nn	o
in	in	o
the	dt	o
executing	vbg	o
goroutine	nn	o
.	.	o
At	in	o
that	wdt	o
point	nn	o
,	,	o
the	dt	o
program	nn	o
is	vbz	o
terminated	vbn	o
and	cc	o
the	dt	o
error	nn	o
condition	nn	o
is	vbz	o
reported	vbn	o
,	,	o
including	vbg	o
the	dt	o
value	nn	o
of	in	o
the	dt	o
argument	nn	o
to	to	o
.	.	o
This	dt	o
termination	nn	o
sequence	nn	o
is	vbz	o
called	vbd	o
panicking	nn	o
.	.	o
The	dt	o
function	nn	o
allows	vbz	o
a	dt	o
program	nn	o
to	to	o
manage	vb	o
behavior	nn	o
of	in	o
a	dt	o
panicking	vbg	o
goroutine	nn	o
.	.	o
Suppose	vb	o
a	dt	o
function	nn	o
defers	vbz	o
a	dt	o
function	nn	o
that	wdt	o
calls	vbz	o
and	cc	o
a	dt	o
panic	nn	o
occurs	nn	o
in	in	o
a	dt	o
function	nn	o
on	in	o
the	dt	o
same	jj	o
goroutine	nn	o
in	in	o
which	wdt	o
is	vbz	o
executing	vbg	o
.	.	o
When	wrb	o
the	dt	o
running	nn	o
of	in	o
deferred	jj	o
functions	nns	o
reaches	nns	o
,	,	o
the	dt	o
return	vb	o
value	nn	o
of	in	o
's	pos	o
call	nn	o
to	to	o
will	md	o
be	vb	o
the	dt	o
value	nn	o
passed	vbd	o
to	to	o
the	dt	o
call	nn	o
of	in	o
.	.	o
If	in	o
returns	nns	o
normally	rb	o
,	,	o
without	in	o
starting	vbg	o
a	dt	o
new	jj	o
,	,	o
the	dt	o
panicking	vbg	o
sequence	nn	o
stops	nns	o
.	.	o
In	in	o
that	wdt	o
case	nn	o
,	,	o
the	dt	o
state	nn	o
of	in	o
functions	nns	o
called	vbd	o
between	in	o
and	cc	o
the	dt	o
call	nn	o
to	to	o
is	vbz	o
discarded	vbn	o
,	,	o
and	cc	o
normal	jj	o
execution	nn	o
resumes	nns	o
.	.	o
Any	dt	o
functions	nns	o
deferred	jj	o
by	in	o
before	in	o
are	vbp	o
then	rb	o
run	jj	o
and	cc	o
's	pos	o
execution	nn	o
terminates	nns	o
by	in	o
returning	vbg	o
to	to	o
its	prp$	o
caller	nn	o
.	.	o
The	dt	o
return	vb	o
value	nn	o
of	in	o
is	vbz	o
if	in	o
any	dt	o
of	in	o
the	dt	o
following	vbg	o
conditions	nns	o
holds	vbz	o
:	:	o
's	pos	o
argument	nn	o
was	vbd	o
;	:	o
the	dt	o
goroutine	nn	o
is	vbz	o
not	rb	o
panicking	vbg	o
;	:	o
was	vbd	o
not	rb	o
called	vbd	o
directly	rb	o
by	in	o
a	dt	o
deferred	jj	o
function	nn	o
.	.	o
The	dt	o
function	nn	o
in	in	o
the	dt	o
example	nn	o
below	in	o
invokes	vbz	o
the	dt	o
function	nn	o
argument	nn	o
and	cc	o
protects	vbz	o
callers	nns	o
from	in	o
run-time	jj	o
panics	nns	o
raised	vbn	o
by	in	o
.	.	o
Bootstrapping	nnp	o
Current	nnp	o
implementations	nns	o
provide	vbp	o
several	jj	o
built-in	jj	o
functions	nns	o
useful	jj	o
during	in	o
bootstrapping	vbg	o
.	.	o
These	dt	o
functions	nns	o
are	vbp	o
documented	vbn	o
for	in	o
completeness	nn	o
but	cc	o
are	vbp	o
not	rb	o
guaranteed	vbn	o
to	to	o
stay	vb	o
in	in	o
the	dt	o
language	nn	o
.	.	o
They	prp	o
do	vbp	o
not	rb	o
return	vb	o
a	dt	o
result	nn	o
.	.	o
Function	nnp	b-person
Behavior	nnp	i-organization
print	nn	o
prints	nns	o
all	pdt	o
arguments	nns	o
;	:	o
formatting	vbg	o
of	in	o
arguments	nns	o
is	vbz	o
implementation-specific	jj	o
println	nns	o
like	in	o
print	nn	o
but	cc	o
prints	nns	o
spaces	nns	o
between	in	o
arguments	nns	o
and	cc	o
a	dt	o
newline	nn	o
at	in	o
the	dt	o
end	nn	o
Implementation	nnp	o
restriction	nn	o
:	:	o
and	cc	o
need	md	o
not	rb	o
accept	vb	o
arbitrary	jj	o
argument	nn	o
types	nns	o
,	,	o
but	cc	o
printing	nn	o
of	in	o
boolean	nn	o
,	,	o
numeric	jj	o
,	,	o
and	cc	o
string	vbg	o
types	nns	o
must	md	o
be	vb	o
supported	vbn	o
.	.	o
Packages	nns	o
Go	nnp	o
programs	nns	o
are	vbp	o
constructed	vbn	o
by	in	o
linking	vbg	o
together	rb	o
packages	nns	o
.	.	o
A	dt	o
package	nn	o
in	in	o
turn	nn	o
is	vbz	o
constructed	vbn	o
from	in	o
one	nn	o
or	cc	o
more	jjr	o
source	nn	o
files	nns	o
that	wdt	o
together	rb	o
declare	vb	o
constants	nns	o
,	,	o
types	nns	o
,	,	o
variables	nns	o
and	cc	o
functions	nns	o
belonging	vbg	o
to	to	o
the	dt	o
package	nn	o
and	cc	o
which	wdt	o
are	vbp	o
accessible	jj	o
in	in	o
all	pdt	o
files	nns	o
of	in	o
the	dt	o
same	jj	o
package	nn	o
.	.	o
Those	dt	o
elements	nns	o
may	md	o
be	vb	o
exported	jj	o
and	cc	o
used	vbn	o
in	in	o
another	dt	o
package	nn	o
.	.	o
Source	nnp	b-gpe
file	nn	o
organization	nn	o
Each	dt	o
source	nn	o
file	nn	o
consists	vbz	o
of	in	o
a	dt	o
package	nn	o
clause	nn	o
defining	vbg	o
the	dt	o
package	nn	o
to	to	o
which	wdt	o
it	prp	o
belongs	vbz	o
,	,	o
followed	vbn	o
by	in	o
a	dt	o
possibly	rb	o
empty	jj	o
set	nn	o
of	in	o
import	nn	o
declarations	nns	o
that	wdt	o
declare	vb	o
packages	nns	o
whose	wp$	o
contents	nns	o
it	prp	o
wishes	vbz	o
to	to	o
use	vb	o
,	,	o
followed	vbn	o
by	in	o
a	dt	o
possibly	rb	o
empty	jj	o
set	nn	o
of	in	o
declarations	nns	o
of	in	o
functions	nns	o
,	,	o
types	nns	o
,	,	o
variables	nns	o
,	,	o
and	cc	o
constants	nns	o
.	.	o
Package	vb	o
clause	nn	o
A	dt	o
package	nn	o
clause	nn	o
begins	vbz	o
each	dt	o
source	nn	o
file	nn	o
and	cc	o
defines	vbz	o
the	dt	o
package	nn	o
to	to	o
which	wdt	o
the	dt	o
file	nn	o
belongs	nns	o
.	.	o
The	dt	o
PackageName	nnp	b-gpe
must	md	o
not	rb	o
be	vb	o
the	dt	o
blank	jj	o
identifier	nn	o
.	.	o
A	dt	o
set	nn	o
of	in	o
files	nns	o
sharing	vbg	o
the	dt	o
same	jj	o
PackageName	nnp	b-gpe
form	nn	o
the	dt	o
implementation	nn	o
of	in	o
a	dt	o
package	nn	o
.	.	o
An	dt	o
implementation	nn	o
may	md	o
require	vb	o
that	wdt	o
all	pdt	o
source	nn	o
files	nns	o
for	in	o
a	dt	o
package	nn	o
inhabit	nn	o
the	dt	o
same	jj	o
directory	nn	o
.	.	o
Import	nnp	b-person
declarations	nns	o
An	dt	o
import	nn	o
declaration	nn	o
states	vbz	o
that	wdt	o
the	dt	o
source	nn	o
file	nn	o
containing	vbg	o
the	dt	o
declaration	nn	o
depends	vbz	o
on	in	o
functionality	nn	o
of	in	o
the	dt	o
imported	vbn	o
package	nn	o
(	(	o
§Program	jj	o
initialization	nn	o
and	cc	o
execution	nn	o
)	)	o
and	cc	o
enables	vbz	o
access	nn	o
to	to	o
exported	jj	o
identifiers	nns	o
of	in	o
that	wdt	o
package	nn	o
.	.	o
The	dt	o
import	nn	o
names	vbz	o
an	dt	o
identifier	nn	o
(	(	o
PackageName	nnp	b-gpe
)	)	o
to	to	o
be	vb	o
used	vbn	o
for	in	o
access	nn	o
and	cc	o
an	dt	o
ImportPath	nnp	b-gpe
that	wdt	o
specifies	vbz	o
the	dt	o
package	nn	o
to	to	o
be	vb	o
imported	vbn	o
.	.	o
The	dt	o
PackageName	nnp	b-gpe
is	vbz	o
used	vbn	o
in	in	o
qualified	jj	o
identifiers	nns	o
to	to	o
access	nn	o
exported	jj	o
identifiers	nns	o
of	in	o
the	dt	o
package	nn	o
within	in	o
the	dt	o
importing	nn	o
source	nn	o
file	nn	o
.	.	o
It	prp	o
is	vbz	o
declared	vbn	o
in	in	o
the	dt	o
file	nn	o
block	nn	o
.	.	o
If	in	o
the	dt	o
PackageName	nnp	b-gpe
is	vbz	o
omitted	vbn	o
,	,	o
it	prp	o
defaults	vbz	o
to	to	o
the	dt	o
identifier	nn	o
specified	vbn	o
in	in	o
the	dt	o
package	nn	o
clause	nn	o
of	in	o
the	dt	o
imported	vbn	o
package	nn	o
.	.	o
If	in	o
an	dt	o
explicit	jj	o
period	nn	o
(	(	o
)	)	o
appears	vbz	o
instead	rb	o
of	in	o
a	dt	o
name	nn	o
,	,	o
all	pdt	o
the	dt	o
package	nn	o
's	pos	o
exported	jj	o
identifiers	nns	o
declared	vbn	o
in	in	o
that	wdt	o
package	nn	o
's	pos	o
package	nn	o
block	nn	o
will	md	o
be	vb	o
declared	vbn	o
in	in	o
the	dt	o
importing	nn	o
source	nn	o
file	nn	o
's	pos	o
file	nn	o
block	nn	o
and	cc	o
must	md	o
be	vb	o
accessed	vbn	o
without	in	o
a	dt	o
qualifier	nn	o
.	.	o
The	dt	o
interpretation	nn	o
of	in	o
the	dt	o
ImportPath	nnp	b-gpe
is	vbz	o
implementation-dependent	jj	o
but	cc	o
it	prp	o
is	vbz	o
typically	rb	o
a	dt	o
substring	nn	o
of	in	o
the	dt	o
full	jj	o
file	nn	o
name	nn	o
of	in	o
the	dt	o
compiled	jj	o
package	nn	o
and	cc	o
may	md	o
be	vb	o
relative	vbp	o
to	to	o
a	dt	o
repository	nn	o
of	in	o
installed	vbd	o
packages	nns	o
.	.	o
Implementation	nnp	o
restriction	nn	o
:	:	o
A	dt	o
compiler	nn	o
may	md	o
restrict	vb	o
ImportPaths	nnp	o
to	to	o
non-empty	jj	o
strings	nns	o
using	vbg	o
only	rb	o
characters	nns	o
belonging	vbg	o
to	to	o
Unicode	nnp	b-gpe
's	pos	o
L	nnp	o
,	,	o
M	nnp	b-gpe
,	,	o
N	nnp	b-gpe
,	,	o
P	nnp	b-gpe
,	,	o
and	cc	o
S	nnp	o
general	jj	o
categories	nns	o
(	(	o
the	dt	o
Graphic	nnp	b-gpe
characters	nns	o
without	in	o
spaces	nns	o
)	)	o
and	cc	o
may	md	o
also	rb	o
exclude	vb	o
the	dt	o
characters	nns	o
and	cc	o
the	dt	o
Unicode	nnp	b-gpe
replacement	nn	o
character	nn	o
U+FFFD	nnp	b-gpe
.	.	o
Assume	nnp	o
we	prp	o
have	vb	o
compiled	jj	o
a	dt	o
package	nn	o
containing	vbg	o
the	dt	o
package	nn	o
clause	nn	o
,	,	o
which	wdt	o
exports	nns	o
function	nn	o
,	,	o
and	cc	o
installed	vbd	o
the	dt	o
compiled	jj	o
package	nn	o
in	in	o
the	dt	o
file	nn	o
identified	vbn	o
by	in	o
.	.	o
This	dt	o
table	nn	o
illustrates	vbz	o
how	wrb	o
is	vbz	o
accessed	vbn	o
in	in	o
files	nns	o
that	wdt	o
import	nn	o
the	dt	o
package	nn	o
after	in	o
the	dt	o
various	jj	o
types	nns	o
of	in	o
import	nn	o
declaration	nn	o
.	.	o
Import	nnp	b-person
declaration	nn	o
Local	nnp	b-person
name	nn	o
of	in	o
Sin	nnp	o
import	nn	o
"	jj	o
lib/math	nn	o
"	nnp	o
math.Sin	nn	o
import	nn	o
m	nn	o
"	jj	o
lib/math	nn	o
"	nnp	o
m.Sin	nn	o
import	nn	o
.	.	o
"	jj	o
lib/math	nn	o
"	nnp	o
Sin	nnp	o
An	dt	o
import	nn	o
declaration	nn	o
declares	vbz	o
a	dt	o
dependency	nn	o
relation	nn	o
between	in	o
the	dt	o
importing	nn	o
and	cc	o
imported	vbn	o
package	nn	o
.	.	o
It	prp	o
is	vbz	o
illegal	jj	o
for	in	o
a	dt	o
package	nn	o
to	to	o
import	nn	o
itself	prp	o
,	,	o
directly	rb	o
or	cc	o
indirectly	rb	o
,	,	o
or	cc	o
to	to	o
directly	rb	o
import	nn	o
a	dt	o
package	nn	o
without	in	o
referring	vbg	o
to	to	o
any	dt	o
of	in	o
its	prp$	o
exported	jj	o
identifiers	nns	o
.	.	o
To	to	o
import	nn	o
a	dt	o
package	nn	o
solely	rb	o
for	in	o
its	prp$	o
side-effects	nns	o
(	(	o
initialization	nn	o
)	)	o
,	,	o
use	vbp	o
the	dt	o
blank	jj	o
identifier	nn	o
as	in	o
explicit	jj	o
package	nn	o
name	nn	o
:	:	o
An	dt	o
example	nn	o
package	nn	o
Here	rb	o
is	vbz	o
a	dt	o
complete	jj	o
Go	nnp	o
package	nn	o
that	wdt	o
implements	vbz	o
a	dt	o
concurrent	jj	o
prime	jj	o
sieve	nn	o
.	.	o
Program	nnp	o
initialization	nn	o
and	cc	o
execution	nn	o
The	dt	o
zero	nn	o
value	nn	o
When	wrb	o
storage	nn	o
is	vbz	o
allocated	vbn	o
for	in	o
a	dt	o
variable	jj	o
,	,	o
either	dt	o
through	in	o
a	dt	o
declaration	nn	o
or	cc	o
a	dt	o
call	nn	o
of	in	o
,	,	o
or	cc	o
when	wrb	o
a	dt	o
new	jj	o
value	nn	o
is	vbz	o
created	vbn	o
,	,	o
either	dt	o
through	in	o
a	dt	o
composite	jj	o
literal	nn	o
or	cc	o
a	dt	o
call	nn	o
of	in	o
,	,	o
and	cc	o
no	dt	o
explicit	jj	o
initialization	nn	o
is	vbz	o
provided	vbn	o
,	,	o
the	dt	o
variable	nn	o
or	cc	o
value	nn	o
is	vbz	o
given	vbn	o
a	dt	o
default	nn	o
value	nn	o
.	.	o
Each	dt	o
element	nn	o
of	in	o
such	jj	o
a	dt	o
variable	nn	o
or	cc	o
value	nn	o
is	vbz	o
set	nn	o
to	to	o
the	dt	o
zero	nn	o
value	nn	o
for	in	o
its	prp$	o
type	nn	o
:	:	o
for	in	o
booleans	nns	o
,	,	o
for	in	o
numeric	jj	o
types	nns	o
,	,	o
for	in	o
strings	nns	o
,	,	o
and	cc	o
for	in	o
pointers	nns	o
,	,	o
functions	nns	o
,	,	o
interfaces	nns	o
,	,	o
slices	nns	o
,	,	o
channels	nns	o
,	,	o
and	cc	o
maps	nns	o
.	.	o
This	dt	o
initialization	nn	o
is	vbz	o
done	vbn	o
recursively	rb	o
,	,	o
so	rb	o
for	in	o
instance	nn	o
each	dt	o
element	nn	o
of	in	o
an	dt	o
array	nn	o
of	in	o
structs	nns	o
will	md	o
have	vb	o
its	prp$	o
fields	nns	o
zeroed	in	o
if	in	o
no	dt	o
value	nn	o
is	vbz	o
specified	vbn	o
.	.	o
These	dt	o
two	cd	o
simple	nn	o
declarations	nns	o
are	vbp	o
equivalent	jj	o
:	:	o
After	in	o
the	dt	o
following	vbg	o
holds	vbz	o
:	:	o
The	dt	o
same	jj	o
would	md	o
also	rb	o
be	vb	o
true	jj	o
after	in	o
Package	vb	o
initialization	nn	o
Within	in	o
a	dt	o
package	nn	o
,	,	o
package-level	nn	o
variable	nn	o
initialization	nn	o
proceeds	nns	o
stepwise	nn	o
,	,	o
with	in	o
each	dt	o
step	nn	o
selecting	vbg	o
the	dt	o
variable	nn	o
earliest	jjs	o
in	in	o
declaration	nn	o
order	nn	o
which	wdt	o
has	vbz	o
no	dt	o
dependencies	nns	o
on	in	o
uninitialized	jj	o
variables	nns	o
.	.	o
More	rbr	o
precisely	rb	o
,	,	o
a	dt	o
package-level	nn	o
variable	nn	o
is	vbz	o
considered	vbn	o
ready	vbp	o
for	in	o
initialization	nn	o
if	in	o
it	prp	o
is	vbz	o
not	rb	o
yet	rb	o
initialized	vbn	o
and	cc	o
either	dt	o
has	vbz	o
no	dt	o
initialization	nn	o
expression	nn	o
or	cc	o
its	prp$	o
initialization	nn	o
expression	nn	o
has	vbz	o
no	dt	o
dependencies	nns	o
on	in	o
uninitialized	jj	o
variables	nns	o
.	.	o
Initialization	nnp	o
proceeds	nns	o
by	in	o
repeatedly	rb	o
initializing	vbg	o
the	dt	o
next	jj	o
package-level	nn	o
variable	nn	o
that	wdt	o
is	vbz	o
earliest	jjs	o
in	in	o
declaration	nn	o
order	nn	o
and	cc	o
ready	vbp	o
for	in	o
initialization	nn	o
,	,	o
until	in	o
there	ex	o
are	vbp	o
no	dt	o
variables	nns	o
ready	vbp	o
for	in	o
initialization	nn	o
.	.	o
If	in	o
any	dt	o
variables	nns	o
are	vbp	o
still	rb	o
uninitialized	jj	o
when	wrb	o
this	dt	o
process	nn	o
ends	vbz	o
,	,	o
those	dt	o
variables	nns	o
are	vbp	o
part	nn	o
of	in	o
one	nn	o
or	cc	o
more	jjr	o
initialization	nn	o
cycles	nns	o
,	,	o
and	cc	o
the	dt	o
program	nn	o
is	vbz	o
not	rb	o
valid	jj	o
.	.	o
Multiple	nnp	o
variables	nns	o
on	in	o
the	dt	o
left-hand	jj	o
side	nn	o
of	in	o
a	dt	o
variable	nn	o
declaration	nn	o
initialized	vbn	o
by	in	o
single	jj	o
(	(	o
multi-valued	jj	o
)	)	o
expression	nn	o
on	in	o
the	dt	o
right-hand	jj	o
side	nn	o
are	vbp	o
initialized	vbn	o
together	rb	o
:	:	o
If	in	o
any	dt	o
of	in	o
the	dt	o
variables	nns	o
on	in	o
the	dt	o
left-hand	jj	o
side	nn	o
is	vbz	o
initialized	vbn	o
,	,	o
all	pdt	o
those	dt	o
variables	nns	o
are	vbp	o
initialized	vbn	o
in	in	o
the	dt	o
same	jj	o
step	nn	o
.	.	o
For	in	o
the	dt	o
purpose	nn	o
of	in	o
package	nn	o
initialization	nn	o
,	,	o
blank	jj	o
variables	nns	o
are	vbp	o
treated	vbn	o
like	in	o
any	dt	o
other	jj	o
variables	nns	o
in	in	o
declarations	nns	o
.	.	o
The	dt	o
declaration	nn	o
order	nn	o
of	in	o
variables	nns	o
declared	vbn	o
in	in	o
multiple	nn	o
files	nns	o
is	vbz	o
determined	vbn	o
by	in	o
the	dt	o
order	nn	o
in	in	o
which	wdt	o
the	dt	o
files	nns	o
are	vbp	o
presented	vbn	o
to	to	o
the	dt	o
compiler	nn	o
:	:	o
Variables	nns	o
declared	vbn	o
in	in	o
the	dt	o
first	jj	o
file	nn	o
are	vbp	o
declared	vbn	o
before	in	o
any	dt	o
of	in	o
the	dt	o
variables	nns	o
declared	vbn	o
in	in	o
the	dt	o
second	jj	o
file	nn	o
,	,	o
and	cc	o
so	rb	o
on	in	o
.	.	o
Dependency	nnp	o
analysis	nn	o
does	vbz	o
not	rb	o
rely	vb	o
on	in	o
the	dt	o
actual	jj	o
values	nns	o
of	in	o
the	dt	o
variables	nns	o
,	,	o
only	rb	o
on	in	o
lexical	jj	o
references	vbz	o
to	to	o
them	prp	o
in	in	o
the	dt	o
source	nn	o
,	,	o
analyzed	vbn	o
transitively	rb	o
.	.	o
For	in	o
instance	nn	o
,	,	o
if	in	o
a	dt	o
variable	nn	o
's	pos	o
initialization	nn	o
expression	nn	o
refers	nns	o
to	to	o
a	dt	o
function	nn	o
whose	wp$	o
body	nn	o
refers	nns	o
to	to	o
variable	nn	o
then	rb	o
depends	vbz	o
on	in	o
.	.	o
Specifically	rb	o
:	:	o
A	dt	o
reference	nn	o
to	to	o
a	dt	o
variable	nn	o
or	cc	o
function	nn	o
is	vbz	o
an	dt	o
identifier	nn	o
denoting	vbg	o
that	wdt	o
variable	nn	o
or	cc	o
function	nn	o
.	.	o
A	dt	o
reference	nn	o
to	to	o
a	dt	o
method	nn	o
is	vbz	o
a	dt	o
method	nn	o
value	nn	o
or	cc	o
method	nn	o
expression	nn	o
of	in	o
the	dt	o
form	nn	o
,	,	o
where	wrb	o
the	dt	o
(	(	o
static	jj	o
)	)	o
type	nn	o
of	in	o
is	vbz	o
not	rb	o
an	dt	o
interface	nn	o
type	nn	o
,	,	o
and	cc	o
the	dt	o
method	nn	o
is	vbz	o
in	in	o
the	dt	o
method	nn	o
set	nn	o
of	in	o
.	.	o
It	prp	o
is	vbz	o
immaterial	jj	o
whether	in	o
the	dt	o
resulting	vbg	o
function	nn	o
value	nn	o
is	vbz	o
invoked	vbn	o
.	.	o
A	dt	o
variable	jj	o
,	,	o
function	nn	o
,	,	o
or	cc	o
method	nn	o
depends	vbz	o
on	in	o
a	dt	o
variable	nn	o
if	in	o
's	pos	o
initialization	nn	o
expression	nn	o
or	cc	o
body	nn	o
(	(	o
for	in	o
functions	nns	o
and	cc	o
methods	nns	o
)	)	o
contains	vbz	o
a	dt	o
reference	nn	o
to	to	o
or	cc	o
to	to	o
a	dt	o
function	nn	o
or	cc	o
method	nn	o
that	wdt	o
depends	vbz	o
on	in	o
.	.	o
For	in	o
example	nn	o
,	,	o
given	vbn	o
the	dt	o
declarations	nns	o
the	dt	o
initialization	nn	o
order	nn	o
is	vbz	o
,	,	o
,	,	o
,	,	o
.	.	o
Note	nn	o
that	wdt	o
the	dt	o
order	nn	o
of	in	o
subexpressions	nns	o
in	in	o
initialization	nn	o
expressions	nns	o
is	vbz	o
irrelevant	jj	o
:	:	o
and	cc	o
result	nn	o
in	in	o
the	dt	o
same	jj	o
initialization	nn	o
order	nn	o
in	in	o
this	dt	o
example	nn	o
.	.	o
Dependency	nnp	o
analysis	nn	o
is	vbz	o
performed	vbn	o
per	in	o
package	nn	o
;	:	o
only	rb	o
references	vbz	o
referring	vbg	o
to	to	o
variables	nns	o
,	,	o
functions	nns	o
,	,	o
and	cc	o
(	(	o
non-interface	nn	o
)	)	o
methods	nns	o
declared	vbn	o
in	in	o
the	dt	o
current	jj	o
package	nn	o
are	vbp	o
considered	vbn	o
.	.	o
If	in	o
other	jj	o
,	,	o
hidden	jj	o
,	,	o
data	nns	o
dependencies	nns	o
exists	vbz	o
between	in	o
variables	nns	o
,	,	o
the	dt	o
initialization	nn	o
order	nn	o
between	in	o
those	dt	o
variables	nns	o
is	vbz	o
unspecified	jj	o
.	.	o
For	in	o
instance	nn	o
,	,	o
given	vbn	o
the	dt	o
declarations	nns	o
the	dt	o
variable	nn	o
will	md	o
be	vb	o
initialized	vbn	o
after	in	o
but	cc	o
whether	in	o
is	vbz	o
initialized	vbn	o
before	in	o
,	,	o
between	in	o
and	cc	o
,	,	o
or	cc	o
after	in	o
,	,	o
and	cc	o
thus	rb	o
also	rb	o
the	dt	o
moment	nn	o
at	in	o
which	wdt	o
is	vbz	o
called	vbd	o
(	(	o
before	in	o
or	cc	o
after	in	o
is	vbz	o
initialized	vbn	o
)	)	o
is	vbz	o
not	rb	o
specified	vbn	o
.	.	o
Variables	nns	o
may	md	o
also	rb	o
be	vb	o
initialized	vbn	o
using	vbg	o
functions	nns	o
named	vbn	o
declared	vbn	o
in	in	o
the	dt	o
package	nn	o
block	nn	o
,	,	o
with	in	o
no	dt	o
arguments	nns	o
and	cc	o
no	dt	o
result	nn	o
parameters	nns	o
.	.	o
Multiple	nnp	o
such	jj	o
functions	nns	o
may	md	o
be	vb	o
defined	vbn	o
per	in	o
package	nn	o
,	,	o
even	rb	o
within	in	o
a	dt	o
single	jj	o
source	nn	o
file	nn	o
.	.	o
In	in	o
the	dt	o
package	nn	o
block	nn	o
,	,	o
the	dt	o
identifier	nn	o
can	md	o
be	vb	o
used	vbn	o
only	rb	o
to	to	o
declare	vb	o
functions	nns	o
,	,	o
yet	rb	o
the	dt	o
identifier	nn	o
itself	prp	o
is	vbz	o
not	rb	o
declared	vbn	o
.	.	o
Thus	nnp	o
functions	nns	o
cannot	vbp	o
be	vb	o
referred	vbn	o
to	to	o
from	in	o
anywhere	rb	o
in	in	o
a	dt	o
program	nn	o
.	.	o
A	dt	o
package	nn	o
with	in	o
no	dt	o
imports	nns	o
is	vbz	o
initialized	vbn	o
by	in	o
assigning	vbg	o
initial	jj	o
values	nns	o
to	to	o
all	pdt	o
its	prp$	o
package-level	nn	o
variables	nns	o
followed	vbn	o
by	in	o
calling	vbg	o
all	pdt	o
functions	nns	o
in	in	o
the	dt	o
order	nn	o
they	prp	o
appear	vbp	o
in	in	o
the	dt	o
source	nn	o
,	,	o
possibly	rb	o
in	in	o
multiple	nn	o
files	nns	o
,	,	o
as	in	o
presented	vbn	o
to	to	o
the	dt	o
compiler	nn	o
.	.	o
If	in	o
a	dt	o
package	nn	o
has	vbz	o
imports	vbz	o
,	,	o
the	dt	o
imported	vbn	o
packages	nns	o
are	vbp	o
initialized	vbn	o
before	in	o
initializing	vbg	o
the	dt	o
package	nn	o
itself	prp	o
.	.	o
If	in	o
multiple	nn	o
packages	nns	o
import	nn	o
a	dt	o
package	nn	o
,	,	o
the	dt	o
imported	vbn	o
package	nn	o
will	md	o
be	vb	o
initialized	vbn	o
only	rb	o
once	rb	o
.	.	o
The	dt	o
importing	nn	o
of	in	o
packages	nns	o
,	,	o
by	in	o
construction	nn	o
,	,	o
guarantees	nns	o
that	wdt	o
there	ex	o
can	md	o
be	vb	o
no	dt	o
cyclic	jj	o
initialization	nn	o
dependencies	nns	o
.	.	o
Package	vb	o
initialization—variable	jj	o
initialization	nn	o
and	cc	o
the	dt	o
invocation	nn	o
of	in	o
functions—happens	nns	o
in	in	o
a	dt	o
single	jj	o
goroutine	nn	o
,	,	o
sequentially	rb	o
,	,	o
one	nn	o
package	nn	o
at	in	o
a	dt	o
time	nn	o
.	.	o
An	dt	o
function	nn	o
may	md	o
launch	vb	o
other	jj	o
goroutines	nns	o
,	,	o
which	wdt	o
can	md	o
run	jj	o
concurrently	rb	o
with	in	o
the	dt	o
initialization	nn	o
code	nn	o
.	.	o
However	rb	o
,	,	o
initialization	nn	o
always	rb	o
sequences	vbz	o
the	dt	o
functions	nns	o
:	:	o
it	prp	o
will	md	o
not	rb	o
invoke	vb	o
the	dt	o
next	jj	o
one	nn	o
until	in	o
the	dt	o
previous	jj	o
one	nn	o
has	vbz	o
returned	vbn	o
.	.	o
To	to	o
ensure	vb	o
reproducible	jj	o
initialization	nn	o
behavior	nn	o
,	,	o
build	jj	o
systems	nns	o
are	vbp	o
encouraged	vbn	o
to	to	o
present	vb	o
multiple	nn	o
files	nns	o
belonging	vbg	o
to	to	o
the	dt	o
same	jj	o
package	nn	o
in	in	o
lexical	jj	o
file	nn	o
name	nn	o
order	nn	o
to	to	o
a	dt	o
compiler	nn	o
.	.	o
Program	nnp	o
execution	nn	o
A	dt	o
complete	jj	o
program	nn	o
is	vbz	o
created	vbn	o
by	in	o
linking	vbg	o
a	dt	o
single	jj	o
,	,	o
unimported	jj	o
package	nn	o
called	vbd	o
the	dt	o
main	jj	o
package	nn	o
with	in	o
all	pdt	o
the	dt	o
packages	nns	o
it	prp	o
imports	vbz	o
,	,	o
transitively	rb	o
.	.	o
The	dt	o
main	jj	o
package	nn	o
must	md	o
have	vb	o
package	nn	o
name	nn	o
and	cc	o
declare	vb	o
a	dt	o
function	nn	o
that	wdt	o
takes	vbz	o
no	dt	o
arguments	nns	o
and	cc	o
returns	nns	o
no	dt	o
value	nn	o
.	.	o
Program	nnp	o
execution	nn	o
begins	vbz	o
by	in	o
initializing	vbg	o
the	dt	o
main	jj	o
package	nn	o
and	cc	o
then	rb	o
invoking	vbg	o
the	dt	o
function	nn	o
.	.	o
When	wrb	o
that	wdt	o
function	nn	o
invocation	nn	o
returns	nns	o
,	,	o
the	dt	o
program	nn	o
exits	vbz	o
.	.	o
It	prp	o
does	vbz	o
not	rb	o
wait	vb	o
for	in	o
other	jj	o
(	(	o
non-	jj	o
)	)	o
goroutines	nns	o
to	to	o
complete	vb	o
.	.	o
Errors	nnps	o
The	dt	o
predeclared	jj	o
type	nn	o
is	vbz	o
defined	vbn	o
as	in	o
It	prp	o
is	vbz	o
the	dt	o
conventional	jj	o
interface	nn	o
for	in	o
representing	vbg	o
an	dt	o
error	nn	o
condition	nn	o
,	,	o
with	in	o
the	dt	o
nil	jj	o
value	nn	o
representing	vbg	o
no	dt	o
error	nn	o
.	.	o
For	in	o
instance	nn	o
,	,	o
a	dt	o
function	nn	o
to	to	o
read	vb	o
data	nns	o
from	in	o
a	dt	o
file	nn	o
might	md	o
be	vb	o
defined	vbn	o
:	:	o
Run-time	jj	o
panics	nns	o
Execution	nn	o
errors	nns	o
such	jj	o
as	in	o
attempting	vbg	o
to	to	o
index	nn	o
an	dt	o
array	nn	o
out	in	o
of	in	o
bounds	nns	o
trigger	vbp	o
a	dt	o
run-time	jj	o
panic	nn	o
equivalent	jj	o
to	to	o
a	dt	o
call	nn	o
of	in	o
the	dt	o
built-in	jj	o
function	nn	o
with	in	o
a	dt	o
value	nn	o
of	in	o
the	dt	o
implementation-defined	jj	o
interface	nn	o
type	nn	o
.	.	o
That	dt	o
type	nn	o
satisfies	vbz	o
the	dt	o
predeclared	jj	o
interface	nn	o
type	nn	o
.	.	o
The	dt	o
exact	jj	o
error	nn	o
values	nns	o
that	wdt	o
represent	vbp	o
distinct	jj	o
run-time	jj	o
error	nn	o
conditions	nns	o
are	vbp	o
unspecified	jj	o
.	.	o
System	nn	o
considerations	nns	o
Package	vb	o
The	dt	o
built-in	jj	o
package	nn	o
,	,	o
known	vbn	o
to	to	o
the	dt	o
compiler	nn	o
and	cc	o
accessible	jj	o
through	in	o
the	dt	o
import	nn	o
path	nn	o
,	,	o
provides	vbz	o
facilities	nns	o
for	in	o
low-level	jj	o
programming	nn	o
including	vbg	o
operations	nns	o
that	wdt	o
violate	vbp	o
the	dt	o
type	nn	o
system	nn	o
.	.	o
A	dt	o
package	nn	o
using	vbg	o
must	md	o
be	vb	o
vetted	vbn	o
manually	rb	o
for	in	o
type	nn	o
safety	nn	o
and	cc	o
may	md	o
not	rb	o
be	vb	o
portable	jj	o
.	.	o
The	dt	o
package	nn	o
provides	vbz	o
the	dt	o
following	vbg	o
interface	nn	o
:	:	o
package	nn	o
unsafe	jj	o
type	nn	o
ArbitraryType	nnp	o
int	nn	o
//	nnp	o
shorthand	nn	o
for	in	o
an	dt	o
arbitrary	jj	o
Go	nnp	o
type	nn	o
;	:	o
it	prp	o
is	vbz	o
not	rb	o
a	dt	o
real	jj	o
type	nn	o
type	nn	o
Pointer	nnp	o
*ArbitraryType	nnp	o
func	nn	o
Alignof(variable	nnp	o
ArbitraryType	nnp	o
)	)	o
uintptr	vbp	o
func	nn	o
Offsetof(selector	nnp	o
ArbitraryType	nnp	o
)	)	o
uintptr	vbp	o
func	nn	o
Sizeof(variable	nnp	b-organization
ArbitraryType	nnp	o
)	)	o
uintptr	vbp	o
type	nn	o
IntegerType	nnp	o
int	nn	o
//	nnp	o
shorthand	nn	o
for	in	o
an	dt	o
integer	jj	o
type	nn	o
;	:	o
it	prp	o
is	vbz	o
not	rb	o
a	dt	o
real	jj	o
type	nn	o
func	nn	o
Add(ptr	nnp	b-organization
Pointer	nnp	i-person
,	,	o
len	nnp	o
IntegerType	nnp	o
)	)	o
Pointer	nnp	o
func	nn	o
Slice(ptr	nnp	b-organization
*ArbitraryType	nnp	i-organization
,	,	o
len	nnp	o
IntegerType	nnp	o
)	)	o
[	vbp	o
]ArbitraryType	pdt	o
A	dt	o
is	vbz	o
a	dt	o
pointer	nn	o
type	nn	o
but	cc	o
a	dt	o
value	nn	o
may	md	o
not	rb	o
be	vb	o
dereferenced	vbn	o
.	.	o
Any	dt	o
pointer	nn	o
or	cc	o
value	nn	o
of	in	o
underlying	jj	o
type	nn	o
can	md	o
be	vb	o
converted	vbn	o
to	to	o
a	dt	o
type	nn	o
of	in	o
underlying	jj	o
type	nn	o
and	cc	o
vice	nn	o
versa	nn	o
.	.	o
The	dt	o
effect	nn	o
of	in	o
converting	vbg	o
between	in	o
and	cc	o
is	vbz	o
implementation-defined	jj	o
.	.	o
The	dt	o
functions	nns	o
and	cc	o
take	vb	o
an	dt	o
expression	nn	o
of	in	o
any	dt	o
type	nn	o
and	cc	o
return	vb	o
the	dt	o
alignment	nn	o
or	cc	o
size	nn	o
,	,	o
respectively	rb	o
,	,	o
of	in	o
a	dt	o
hypothetical	jj	o
variable	nn	o
as	in	o
if	in	o
was	vbd	o
declared	vbn	o
via	in	o
.	.	o
The	dt	o
function	nn	o
takes	vbz	o
a	dt	o
(	(	o
possibly	rb	o
parenthesized	vbn	o
)	)	o
selector	nn	o
,	,	o
denoting	vbg	o
a	dt	o
field	nn	o
of	in	o
the	dt	o
struct	nn	o
denoted	vbn	o
by	in	o
or	cc	o
,	,	o
and	cc	o
returns	nns	o
the	dt	o
field	nn	o
offset	nn	o
in	in	o
bytes	nns	o
relative	vbp	o
to	to	o
the	dt	o
struct	nn	o
's	pos	o
address	nn	o
.	.	o
If	in	o
is	vbz	o
an	dt	o
embedded	jj	o
field	nn	o
,	,	o
it	prp	o
must	md	o
be	vb	o
reachable	jj	o
without	in	o
pointer	nn	o
indirections	nns	o
through	in	o
fields	nns	o
of	in	o
the	dt	o
struct	nn	o
.	.	o
For	in	o
a	dt	o
struct	nn	o
with	in	o
field	nn	o
:	:	o
Computer	nnp	o
architectures	vbz	o
may	md	o
require	vb	o
memory	nn	o
addresses	nns	o
to	to	o
be	vb	o
aligned	vbn	o
;	:	o
that	wdt	o
is	vbz	o
,	,	o
for	in	o
addresses	nns	o
of	in	o
a	dt	o
variable	nn	o
to	to	o
be	vb	o
a	dt	o
multiple	nn	o
of	in	o
a	dt	o
factor	nn	o
,	,	o
the	dt	o
variable	nn	o
's	pos	o
type	nn	o
's	pos	o
alignment	nn	o
.	.	o
The	dt	o
function	nn	o
takes	vbz	o
an	dt	o
expression	nn	o
denoting	vbg	o
a	dt	o
variable	nn	o
of	in	o
any	dt	o
type	nn	o
and	cc	o
returns	nns	o
the	dt	o
alignment	nn	o
of	in	o
the	dt	o
(	(	o
type	nn	o
of	in	o
the	dt	o
)	)	o
variable	nn	o
in	in	o
bytes	nns	o
.	.	o
For	in	o
a	dt	o
variable	nn	o
:	:	o
A	dt	o
(	(	o
variable	jj	o
of	in	o
)	)	o
type	nn	o
has	vbz	o
variable	nn	o
size	nn	o
if	in	o
is	vbz	o
a	dt	o
type	nn	o
parameter	nn	o
,	,	o
or	cc	o
if	in	o
it	prp	o
is	vbz	o
an	dt	o
array	nn	o
or	cc	o
struct	nn	o
type	nn	o
containing	vbg	o
elements	nns	o
or	cc	o
fields	nns	o
of	in	o
variable	nn	o
size	nn	o
.	.	o
Otherwise	vb	o
the	dt	o
size	nn	o
is	vbz	o
constant	nn	o
.	.	o
Calls	vbz	o
to	to	o
,	,	o
,	,	o
and	cc	o
are	vbp	o
compile-time	jj	o
constant	nn	o
expressions	nns	o
of	in	o
type	nn	o
if	in	o
their	prp$	o
arguments	nns	o
(	(	o
or	cc	o
the	dt	o
struct	nn	o
in	in	o
the	dt	o
selector	nn	o
expression	nn	o
for	in	o
)	)	o
are	vbp	o
types	nns	o
of	in	o
constant	nn	o
size	nn	o
.	.	o
The	dt	o
function	nn	o
adds	vbz	o
to	to	o
and	cc	o
returns	nns	o
the	dt	o
updated	jj	o
pointer	nn	o
.	.	o
The	dt	o
argument	nn	o
must	md	o
be	vb	o
of	in	o
integer	jj	o
type	nn	o
or	cc	o
an	dt	o
untyped	jj	o
constant	nn	o
.	.	o
A	dt	o
constant	nn	o
argument	nn	o
must	md	o
be	vb	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
;	:	o
if	in	o
it	prp	o
is	vbz	o
an	dt	o
untyped	jj	o
constant	nn	o
it	prp	o
is	vbz	o
given	vbn	o
type	nn	o
.	.	o
The	dt	o
rules	nns	o
for	in	o
valid	jj	o
uses	nns	o
of	in	o
still	rb	o
apply	vb	o
.	.	o
The	dt	o
function	nn	o
returns	nns	o
a	dt	o
slice	nn	o
whose	wp$	o
underlying	jj	o
array	nn	o
starts	vbz	o
at	in	o
and	cc	o
whose	wp$	o
length	nn	o
and	cc	o
capacity	nn	o
are	vbp	o
.	.	o
is	vbz	o
equivalent	jj	o
to	to	o
except	vb	o
that	rb	o
,	,	o
as	in	o
a	dt	o
special	jj	o
case	nn	o
,	,	o
if	in	o
is	vbz	o
and	cc	o
is	vbz	o
zero	cd	o
,	,	o
returns	nns	o
.	.	o
The	dt	o
argument	nn	o
must	md	o
be	vb	o
of	in	o
integer	jj	o
type	nn	o
or	cc	o
an	dt	o
untyped	jj	o
constant	nn	o
.	.	o
A	dt	o
constant	nn	o
argument	nn	o
must	md	o
be	vb	o
non-negative	jj	o
and	cc	o
representable	jj	o
by	in	o
a	dt	o
value	nn	o
of	in	o
type	nn	o
;	:	o
if	in	o
it	prp	o
is	vbz	o
an	dt	o
untyped	jj	o
constant	nn	o
it	prp	o
is	vbz	o
given	vbn	o
type	nn	o
.	.	o
At	in	o
run	jj	o
time	nn	o
,	,	o
if	in	o
is	vbz	o
negative	jj	o
,	,	o
or	cc	o
if	in	o
is	vbz	o
and	cc	o
is	vbz	o
not	rb	o
zero	cd	o
,	,	o
a	dt	o
run-time	jj	o
panic	nn	o
occurs	nns	o
.	.	o
Size	nnp	b-person
and	cc	o
alignment	nn	o
guarantees	nns	o
For	in	o
the	dt	o
numeric	jj	o
types	nns	o
,	,	o
the	dt	o
following	vbg	o
sizes	nns	o
are	vbp	o
guaranteed	vbn	o
:	:	o
type	nn	o
size	nn	o
in	in	o
bytes	nns	o
byte	vbp	o
,	,	o
uint8	jj	o
,	,	o
int8	jj	o
1	cd	o
uint16	nn	o
,	,	o
int16	jj	o
2	cd	o
uint32	nn	o
,	,	o
int32	nn	o
,	,	o
float32	vbp	o
4	cd	o
uint64	jj	o
,	,	o
int64	jj	o
,	,	o
float64	jj	o
,	,	o
complex64	jj	o
8	cd	o
complex128	nn	o
16	cd	o
The	dt	o
following	vbg	o
minimal	jj	o
alignment	nn	o
properties	nns	o
are	vbp	o
guaranteed	vbn	o
:	:	o
For	in	o
a	dt	o
variable	nn	o
of	in	o
any	dt	o
type	nn	o
:	:	o
is	vbz	o
at	in	o
least	jjs	o
1	cd	o
.	.	o
For	in	o
a	dt	o
variable	nn	o
of	in	o
struct	nn	o
type	nn	o
:	:	o
is	vbz	o
the	dt	o
largest	jjs	o
of	in	o
all	pdt	o
the	dt	o
values	nns	o
for	in	o
each	dt	o
field	nn	o
of	in	o
,	,	o
but	cc	o
at	in	o
least	jjs	o
1	cd	o
.	.	o
For	in	o
a	dt	o
variable	nn	o
of	in	o
array	nn	o
type	nn	o
:	:	o
is	vbz	o
the	dt	o
same	jj	o
as	in	o
the	dt	o
alignment	nn	o
of	in	o
a	dt	o
variable	nn	o
of	in	o
the	dt	o
array	nn	o
's	pos	o
element	nn	o
type	nn	o
.	.	o
A	dt	o
struct	nn	o
or	cc	o
array	nn	o
type	nn	o
has	vbz	o
size	nn	o
zero	nn	o
if	in	o
it	prp	o
contains	vbz	o
no	dt	o
fields	nns	o
(	(	o
or	cc	o
elements	nns	o
,	,	o
respectively	rb	o
)	)	o
that	wdt	o
have	vb	o
a	dt	o
size	nn	o
greater	jjr	o
than	in	o
zero	cd	o
.	.	o
Two	cd	o
distinct	jj	o
zero-size	jj	o
variables	nns	o
may	md	o
have	vb	o
the	dt	o
same	jj	o
address	nn	o
in	in	o
memory	nn	o
.	.	o