]>
Commit | Line | Data |
---|---|---|
f20569fa XL |
1 | // run-rustfix |
2 | ||
3 | #![warn(clippy::while_let_on_iterator)] | |
4 | #![allow(clippy::never_loop, unreachable_code, unused_mut)] | |
f20569fa XL |
5 | |
6 | fn base() { | |
7 | let mut iter = 1..20; | |
8 | while let Option::Some(x) = iter.next() { | |
9 | println!("{}", x); | |
10 | } | |
11 | ||
12 | let mut iter = 1..20; | |
13 | while let Some(x) = iter.next() { | |
14 | println!("{}", x); | |
15 | } | |
16 | ||
17 | let mut iter = 1..20; | |
18 | while let Some(_) = iter.next() {} | |
19 | ||
20 | let mut iter = 1..20; | |
21 | while let None = iter.next() {} // this is fine (if nonsensical) | |
22 | ||
23 | let mut iter = 1..20; | |
24 | if let Some(x) = iter.next() { | |
25 | // also fine | |
26 | println!("{}", x) | |
27 | } | |
28 | ||
29 | // the following shouldn't warn because it can't be written with a for loop | |
30 | let mut iter = 1u32..20; | |
31 | while let Some(_) = iter.next() { | |
32 | println!("next: {:?}", iter.next()) | |
33 | } | |
34 | ||
35 | // neither can this | |
36 | let mut iter = 1u32..20; | |
37 | while let Some(_) = iter.next() { | |
38 | println!("next: {:?}", iter.next()); | |
39 | } | |
40 | ||
41 | // or this | |
42 | let mut iter = 1u32..20; | |
43 | while let Some(_) = iter.next() { | |
44 | break; | |
45 | } | |
46 | println!("Remaining iter {:?}", iter); | |
47 | ||
48 | // or this | |
49 | let mut iter = 1u32..20; | |
50 | while let Some(_) = iter.next() { | |
51 | iter = 1..20; | |
52 | } | |
53 | } | |
54 | ||
55 | // Issue #1188 | |
56 | fn refutable() { | |
57 | let a = [42, 1337]; | |
58 | let mut b = a.iter(); | |
59 | ||
60 | // consume all the 42s | |
61 | while let Some(&42) = b.next() {} | |
62 | ||
63 | let a = [(1, 2, 3)]; | |
64 | let mut b = a.iter(); | |
65 | ||
66 | while let Some(&(1, 2, 3)) = b.next() {} | |
67 | ||
68 | let a = [Some(42)]; | |
69 | let mut b = a.iter(); | |
70 | ||
71 | while let Some(&None) = b.next() {} | |
72 | ||
73 | /* This gives “refutable pattern in `for` loop binding: `&_` not covered” | |
74 | for &42 in b {} | |
75 | for &(1, 2, 3) in b {} | |
76 | for &Option::None in b.next() {} | |
77 | // */ | |
78 | } | |
79 | ||
80 | fn refutable2() { | |
81 | // Issue 3780 | |
82 | { | |
83 | let v = vec![1, 2, 3]; | |
84 | let mut it = v.windows(2); | |
85 | while let Some([x, y]) = it.next() { | |
86 | println!("x: {}", x); | |
87 | println!("y: {}", y); | |
88 | } | |
89 | ||
90 | let mut it = v.windows(2); | |
91 | while let Some([x, ..]) = it.next() { | |
92 | println!("x: {}", x); | |
93 | } | |
94 | ||
95 | let mut it = v.windows(2); | |
96 | while let Some([.., y]) = it.next() { | |
97 | println!("y: {}", y); | |
98 | } | |
99 | ||
100 | let mut it = v.windows(2); | |
101 | while let Some([..]) = it.next() {} | |
102 | ||
103 | let v = vec![[1], [2], [3]]; | |
104 | let mut it = v.iter(); | |
105 | while let Some([1]) = it.next() {} | |
106 | ||
107 | let mut it = v.iter(); | |
108 | while let Some([_x]) = it.next() {} | |
109 | } | |
110 | ||
111 | // binding | |
112 | { | |
113 | let v = vec![1, 2, 3]; | |
114 | let mut it = v.iter(); | |
115 | while let Some(x @ 1) = it.next() { | |
116 | println!("{}", x); | |
117 | } | |
118 | ||
119 | let v = vec![[1], [2], [3]]; | |
120 | let mut it = v.iter(); | |
121 | while let Some(x @ [_]) = it.next() { | |
122 | println!("{:?}", x); | |
123 | } | |
124 | } | |
125 | ||
126 | // false negative | |
127 | { | |
128 | let v = vec![1, 2, 3]; | |
129 | let mut it = v.iter().map(Some); | |
130 | while let Some(Some(_) | None) = it.next() { | |
131 | println!("1"); | |
132 | } | |
133 | } | |
134 | } | |
135 | ||
136 | fn nested_loops() { | |
137 | let a = [42, 1337]; | |
138 | let mut y = a.iter(); | |
139 | loop { | |
140 | // x is reused, so don't lint here | |
141 | while let Some(_) = y.next() {} | |
142 | } | |
143 | ||
144 | let mut y = a.iter(); | |
145 | for _ in 0..2 { | |
146 | while let Some(_) = y.next() { | |
147 | // y is reused, don't lint | |
148 | } | |
149 | } | |
150 | ||
151 | loop { | |
152 | let mut y = a.iter(); | |
153 | while let Some(_) = y.next() { | |
154 | // use a for loop here | |
155 | } | |
156 | } | |
157 | } | |
158 | ||
159 | fn issue1121() { | |
160 | use std::collections::HashSet; | |
161 | let mut values = HashSet::new(); | |
162 | values.insert(1); | |
163 | ||
164 | while let Some(&value) = values.iter().next() { | |
165 | values.remove(&value); | |
166 | } | |
167 | } | |
168 | ||
169 | fn issue2965() { | |
170 | // This should not cause an ICE and suggest: | |
171 | // | |
172 | // for _ in values.iter() {} | |
173 | // | |
174 | use std::collections::HashSet; | |
175 | let mut values = HashSet::new(); | |
176 | values.insert(1); | |
177 | ||
178 | while let Some(..) = values.iter().next() {} | |
179 | } | |
180 | ||
181 | fn issue3670() { | |
182 | let array = [Some(0), None, Some(1)]; | |
183 | let mut iter = array.iter(); | |
184 | ||
185 | while let Some(elem) = iter.next() { | |
186 | let _ = elem.or_else(|| *iter.next()?); | |
187 | } | |
188 | } | |
189 | ||
190 | fn issue1654() { | |
191 | // should not lint if the iterator is generated on every iteration | |
192 | use std::collections::HashSet; | |
193 | let mut values = HashSet::new(); | |
194 | values.insert(1); | |
195 | ||
196 | while let Some(..) = values.iter().next() { | |
197 | values.remove(&1); | |
198 | } | |
199 | ||
200 | while let Some(..) = values.iter().map(|x| x + 1).next() {} | |
201 | ||
202 | let chars = "Hello, World!".char_indices(); | |
203 | while let Some((i, ch)) = chars.clone().next() { | |
204 | println!("{}: {}", i, ch); | |
205 | } | |
206 | } | |
207 | ||
208 | fn main() { | |
209 | base(); | |
210 | refutable(); | |
211 | refutable2(); | |
212 | nested_loops(); | |
213 | issue1121(); | |
214 | issue2965(); | |
215 | issue3670(); | |
216 | issue1654(); | |
217 | } |