1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
// run
// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Check that these do not use "by value" capturing,
// because changes are made to the value during the closure.
package main
var never bool
func main() {
{
type X struct {
v int
}
var x X
func() {
x.v++
}()
if x.v != 1 {
panic("x.v != 1")
}
type Y struct {
X
}
var y Y
func() {
y.v = 1
}()
if y.v != 1 {
panic("y.v != 1")
}
}
{
type Z struct {
a [3]byte
}
var z Z
func() {
i := 0
for z.a[1] = 1; i < 10; i++ {
}
}()
if z.a[1] != 1 {
panic("z.a[1] != 1")
}
}
{
w := 0
tmp := 0
f := func() {
if w != 1 {
panic("w != 1")
}
}
func() {
tmp = w // force capture of w, but do not write to it yet
_ = tmp
func() {
func() {
w++ // write in a nested closure
}()
}()
}()
f()
}
{
var g func() int
var i int
for i = range [2]int{} {
if i == 0 {
g = func() int {
return i // test that we capture by ref here, i is mutated on every interaction
}
}
}
if g() != 1 {
panic("g() != 1")
}
}
{
var g func() int
q := 0
for range [2]int{} {
q++
g = func() int {
return q // test that we capture by ref here
// q++ must on a different decldepth than q declaration
}
}
if g() != 2 {
panic("g() != 2")
}
}
{
var g func() int
var a [2]int
q := 0
for a[func() int {
q++
return 0
}()] = range [2]int{} {
g = func() int {
return q // test that we capture by ref here
// q++ must on a different decldepth than q declaration
}
}
if g() != 2 {
panic("g() != 2")
}
}
{
var g func() int
q := 0
q, g = 1, func() int { return q }
if never {
g = func() int { return 2 }
}
if g() != 1 {
panic("g() != 1")
}
}
}
|
