src/librustc_error_codes/error_codes/E0571.md

   1 A `break` statement with an argument appeared in a non-`loop` loop.
   2
   3 Example of erroneous code:
   4
   5 ```compile_fail,E0571
   6 # let mut i = 1;
   7 # fn satisfied(n: usize) -> bool { n % 23 == 0 }
   8 let result = while true {
   9     if satisfied(i) {
  10         break 2*i; // error: `break` with value from a `while` loop
  11     }
  12     i += 1;
  13 };
  14 ```
  15
  16 The `break` statement can take an argument (which will be the value of the loop
  17 expression if the `break` statement is executed) in `loop` loops, but not
  18 `for`, `while`, or `while let` loops.
  19
  20 Make sure `break value;` statements only occur in `loop` loops:
  21
  22 ```
  23 # let mut i = 1;
  24 # fn satisfied(n: usize) -> bool { n % 23 == 0 }
  25 let result = loop { // ok!
  26     if satisfied(i) {
  27         break 2*i;
  28     }
  29     i += 1;
  30 };
  31 ```