Macro polonius_the_crab::prelude::polonius_break

macro_rules! polonius_break {
    ( $($e:expr $(,)?)? ) => { ... };
}

break a non-dependent value out of a polonius_loop!.

• When the value to break with is a dependent value / a value that is borrowing from the input, consider using polonius_break_dependent! instead.

Example

• use {
      ::std::{
          collections::HashMap,
      },
      ::polonius_the_crab::{
          *,
      },
  };
  
  fn example (mut map: &'_ mut HashMap<u8, i32>)
    -> Option<&'_ mut i32>
  {
      let mut i = 0;
      let x = polonius_loop!(|map| -> Option<&'polonius mut i32> {
          if let Some(entry) = map.get_mut(&i) {
              polonius_return!(Some(entry));
          }
          i += 1;
          if i == 42 {
              polonius_break!(i);
          }
      });
      assert_eq!(x, i);
      // Access to the "captured" `map` is still possible if using `polonius_break!`
      // (and thus no `break: …` annotation on the "closure")
      map.clear();
      None
  }