src/test/ui/consts/const-eval/infinite_loop.rs

   1 fn main() {
   2     // Tests the Collatz conjecture with an incorrect base case (0 instead of 1).
   3     // The value of `n` will loop indefinitely (4 - 2 - 1 - 4).
   4     let _ = [(); {
   5         //~^ WARNING Constant evaluating a complex constant, this might take some time
   6         let mut n = 113383; // #20 in https://oeis.org/A006884
   7         while n != 0 {
   8         //~^ ERROR `while` is not allowed in a `const`
   9             n = if n % 2 == 0 { n/2 } else { 3*n + 1 };
  10             //~^ ERROR evaluation of constant value failed
  11             //~| ERROR `if` is not allowed in a `const`
  12         }
  13         n
  14     }];
  15 }