src/tools/clippy/tests/ui/never_loop.rs

   1 #![allow(
   2     clippy::single_match,
   3     unused_assignments,
   4     unused_variables,
   5     clippy::while_immutable_condition
   6 )]
   7
   8 fn test1() {
   9     let mut x = 0;
  10     loop {
  11         // clippy::never_loop
  12         x += 1;
  13         if x == 1 {
  14             return;
  15         }
  16         break;
  17     }
  18 }
  19
  20 fn test2() {
  21     let mut x = 0;
  22     loop {
  23         x += 1;
  24         if x == 1 {
  25             break;
  26         }
  27     }
  28 }
  29
  30 fn test3() {
  31     let mut x = 0;
  32     loop {
  33         // never loops
  34         x += 1;
  35         break;
  36     }
  37 }
  38
  39 fn test4() {
  40     let mut x = 1;
  41     loop {
  42         x += 1;
  43         match x {
  44             5 => return,
  45             _ => (),
  46         }
  47     }
  48 }
  49
  50 fn test5() {
  51     let i = 0;
  52     loop {
  53         // never loops
  54         while i == 0 {
  55             // never loops
  56             break;
  57         }
  58         return;
  59     }
  60 }
  61
  62 fn test6() {
  63     let mut x = 0;
  64     'outer: loop {
  65         x += 1;
  66         loop {
  67             // never loops
  68             if x == 5 {
  69                 break;
  70             }
  71             continue 'outer;
  72         }
  73         return;
  74     }
  75 }
  76
  77 fn test7() {
  78     let mut x = 0;
  79     loop {
  80         x += 1;
  81         match x {
  82             1 => continue,
  83             _ => (),
  84         }
  85         return;
  86     }
  87 }
  88
  89 fn test8() {
  90     let mut x = 0;
  91     loop {
  92         x += 1;
  93         match x {
  94             5 => return,
  95             _ => continue,
  96         }
  97     }
  98 }
  99
 100 fn test9() {
 101     let x = Some(1);
 102     while let Some(y) = x {
 103         // never loops
 104         return;
 105     }
 106 }
 107
 108 fn test10() {
 109     for x in 0..10 {
 110         // never loops
 111         match x {
 112             1 => break,
 113             _ => return,
 114         }
 115     }
 116 }
 117
 118 fn test11<F: FnMut() -> i32>(mut f: F) {
 119     loop {
 120         return match f() {
 121             1 => continue,
 122             _ => (),
 123         };
 124     }
 125 }
 126
 127 pub fn test12(a: bool, b: bool) {
 128     'label: loop {
 129         loop {
 130             if a {
 131                 continue 'label;
 132             }
 133             if b {
 134                 break;
 135             }
 136         }
 137         break;
 138     }
 139 }
 140
 141 pub fn test13() {
 142     let mut a = true;
 143     loop {
 144         // infinite loop
 145         while a {
 146             if true {
 147                 a = false;
 148                 continue;
 149             }
 150             return;
 151         }
 152     }
 153 }
 154
 155 pub fn test14() {
 156     let mut a = true;
 157     'outer: while a {
 158         // never loops
 159         while a {
 160             if a {
 161                 a = false;
 162                 continue;
 163             }
 164         }
 165         break 'outer;
 166     }
 167 }
 168
 169 // Issue #1991: the outer loop should not warn.
 170 pub fn test15() {
 171     'label: loop {
 172         while false {
 173             break 'label;
 174         }
 175     }
 176 }
 177
 178 // Issue #4058: `continue` in `break` expression
 179 pub fn test16() {
 180     let mut n = 1;
 181     loop {
 182         break if n != 5 {
 183             n += 1;
 184             continue;
 185         };
 186     }
 187 }
 188
 189 fn main() {
 190     test1();
 191     test2();
 192     test3();
 193     test4();
 194     test5();
 195     test6();
 196     test7();
 197     test8();
 198     test9();
 199     test10();
 200     test11(|| 0);
 201     test12(true, false);
 202     test13();
 203     test14();
 204 }