gopls/go/analysis/passes/loopclosure/testdata/src/a/a.go

1	// Copyright 2012 The Go Authors. All rights reserved.
2	// Use of this source code is governed by a BSD-style
3	// license that can be found in the LICENSE file.
4
5	// This file contains tests for the loopclosure checker.
6
7	package testdata
8
9	import (
10	"sync"
11
12	"golang.org/x/sync/errgroup"
13	)
14
15	var A int
16
17	func _() {
18	var s []int
19	for i, v := range s {
20	go func() {
21	println(i) // want "loop variable i captured by func literal"
22	println(v) // want "loop variable v captured by func literal"
23	}()
24	}
25	for i, v := range s {
26	defer func() {
27	println(i) // want "loop variable i captured by func literal"
28	println(v) // want "loop variable v captured by func literal"
29	}()
30	}
31	for i := range s {
32	go func() {
33	println(i) // want "loop variable i captured by func literal"
34	}()
35	}
36	for _, v := range s {
37	go func() {
38	println(v) // want "loop variable v captured by func literal"
39	}()
40	}
41	for i, v := range s {
42	go func() {
43	println(i, v)
44	}()
45	println("unfortunately, we don't catch the error above because of this statement")
46	}
47	for i, v := range s {
48	go func(i, v int) {
49	println(i, v)
50	}(i, v)
51	}
52	for i, v := range s {
53	i, v := i, v
54	go func() {
55	println(i, v)
56	}()
57	}
58
59	// iteration variable declared outside the loop
60	for A = range s {
61	go func() {
62	println(A) // want "loop variable A captured by func literal"
63	}()
64	}
65	// iteration variable declared in a different file
66	for B = range s {
67	go func() {
68	println(B) // want "loop variable B captured by func literal"
69	}()
70	}
71	// If the key of the range statement is not an identifier
72	// the code should not panic (it used to).
73	var x [2]int
74	var f int
75	for x[0], f = range s {
76	go func() {
77	_ = f // want "loop variable f captured by func literal"
78	}()
79	}
80	type T struct {
81	v int
82	}
83	for _, v := range s {
84	go func() {
85	_ = T{v: 1}
86	_ = map[int]int{v: 1} // want "loop variable v captured by func literal"
87	}()
88	}
89
90	// ordinary for-loops
91	for i := 0; i < 10; i++ {
92	go func() {
93	print(i) // want "loop variable i captured by func literal"
94	}()
95	}
96	for i, j := 0, 1; i < 100; i, j = j, i+j {
97	go func() {
98	print(j) // want "loop variable j captured by func literal"
99	}()
100	}
101	type cons struct {
102	car int
103	cdr *cons
104	}
105	var head *cons
106	for p := head; p != nil; p = p.cdr {
107	go func() {
108	print(p.car) // want "loop variable p captured by func literal"
109	}()
110	}
111	}
112
113	// Cases that rely on recursively checking for last statements.
114	func _() {
115
116	for i := range "outer" {
117	for j := range "inner" {
118	if j < 1 {
119	defer func() {
120	print(i) // want "loop variable i captured by func literal"
121	}()
122	} else if j < 2 {
123	go func() {
124	print(i) // want "loop variable i captured by func literal"
125	}()
126	} else {
127	go func() {
128	print(i)
129	}()
130	println("we don't catch the error above because of this statement")
131	}
132	}
133	}
134
135	for i := 0; i < 10; i++ {
136	for j := 0; j < 10; j++ {
137	if j < 1 {
138	switch j {
139	case 0:
140	defer func() {
141	print(i) // want "loop variable i captured by func literal"
142	}()
143	default:
144	go func() {
145	print(i) // want "loop variable i captured by func literal"
146	}()
147	}
148	} else if j < 2 {
149	var a interface{} = j
150	switch a.(type) {
151	case int:
152	defer func() {
153	print(i) // want "loop variable i captured by func literal"
154	}()
155	default:
156	go func() {
157	print(i) // want "loop variable i captured by func literal"
158	}()
159	}
160	} else {
161	ch := make(chan string)
162	select {
163	case <-ch:
164	defer func() {
165	print(i) // want "loop variable i captured by func literal"
166	}()
167	default:
168	go func() {
169	print(i) // want "loop variable i captured by func literal"
170	}()
171	}
172	}
173	}
174	}
175	}
176
177	// Group is used to test that loopclosure only matches Group.Go when Group is
178	// from the golang.org/x/sync/errgroup package.
179	type Group struct{}
180
181	func (g *Group) Go(func() error) {}
182
183	func _() {
184	var s []int
185	// errgroup.Group.Go() invokes Go routines
186	g := new(errgroup.Group)
187	for i, v := range s {
188	g.Go(func() error {
189	print(i) // want "loop variable i captured by func literal"
190	print(v) // want "loop variable v captured by func literal"
191	return nil
192	})
193	}
194
195	for i, v := range s {
196	if i > 0 {
197	g.Go(func() error {
198	print(i) // want "loop variable i captured by func literal"
199	return nil
200	})
201	} else {
202	g.Go(func() error {
203	print(v) // want "loop variable v captured by func literal"
204	return nil
205	})
206	}
207	}
208
209	// Do not match other Group.Go cases
210	g1 := new(Group)
211	for i, v := range s {
212	g1.Go(func() error {
213	print(i)
214	print(v)
215	return nil
216	})
217	}
218	}
219
220	// Real-world example from #16520, slightly simplified
221	func _() {
222	var nodes []interface{}
223
224	critical := new(errgroup.Group)
225	others := sync.WaitGroup{}
226
227	isCritical := func(node interface{}) bool { return false }
228	run := func(node interface{}) error { return nil }
229
230	for _, node := range nodes {
231	if isCritical(node) {
232	critical.Go(func() error {
233	return run(node) // want "loop variable node captured by func literal"
234	})
235	} else {
236	others.Add(1)
237	go func() {
238	_ = run(node) // want "loop variable node captured by func literal"
239	others.Done()
240	}()
241	}
242	}
243	}
244