|
| 1 | +// run-rustfix |
| 2 | + |
| 3 | +#![warn(clippy::while_let_on_iterator)] |
| 4 | +#![allow(clippy::never_loop, unreachable_code, unused_mut)] |
| 5 | + |
| 6 | +fn base() { |
| 7 | + let mut iter = 1..20; |
| 8 | + for x in iter { |
| 9 | + println!("{}", x); |
| 10 | + } |
| 11 | + |
| 12 | + let mut iter = 1..20; |
| 13 | + for x in iter { |
| 14 | + println!("{}", x); |
| 15 | + } |
| 16 | + |
| 17 | + let mut iter = 1..20; |
| 18 | + for _ in iter {} |
| 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 nested_loops() { |
| 81 | + let a = [42, 1337]; |
| 82 | + let mut y = a.iter(); |
| 83 | + loop { |
| 84 | + // x is reused, so don't lint here |
| 85 | + while let Some(_) = y.next() {} |
| 86 | + } |
| 87 | + |
| 88 | + let mut y = a.iter(); |
| 89 | + for _ in 0..2 { |
| 90 | + while let Some(_) = y.next() { |
| 91 | + // y is reused, don't lint |
| 92 | + } |
| 93 | + } |
| 94 | + |
| 95 | + loop { |
| 96 | + let mut y = a.iter(); |
| 97 | + for _ in y { |
| 98 | + // use a for loop here |
| 99 | + } |
| 100 | + } |
| 101 | +} |
| 102 | + |
| 103 | +fn issue1121() { |
| 104 | + use std::collections::HashSet; |
| 105 | + let mut values = HashSet::new(); |
| 106 | + values.insert(1); |
| 107 | + |
| 108 | + while let Some(&value) = values.iter().next() { |
| 109 | + values.remove(&value); |
| 110 | + } |
| 111 | +} |
| 112 | + |
| 113 | +fn issue2965() { |
| 114 | + // This should not cause an ICE and suggest: |
| 115 | + // |
| 116 | + // for _ in values.iter() {} |
| 117 | + // |
| 118 | + use std::collections::HashSet; |
| 119 | + let mut values = HashSet::new(); |
| 120 | + values.insert(1); |
| 121 | + |
| 122 | + for _ in values.iter() { |
| 123 | + // FIXME(flip1995): Linting this with the following line uncommented is a FP, see #1654 |
| 124 | + // values.remove(&1); |
| 125 | + } |
| 126 | +} |
| 127 | + |
| 128 | +fn issue3670() { |
| 129 | + let array = [Some(0), None, Some(1)]; |
| 130 | + let mut iter = array.iter(); |
| 131 | + |
| 132 | + while let Some(elem) = iter.next() { |
| 133 | + let _ = elem.or_else(|| *iter.next()?); |
| 134 | + } |
| 135 | +} |
| 136 | + |
| 137 | +fn main() { |
| 138 | + base(); |
| 139 | + refutable(); |
| 140 | + nested_loops(); |
| 141 | + issue1121(); |
| 142 | + issue2965(); |
| 143 | + issue3670(); |
| 144 | +} |
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