Macro polonius_try

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

Perform the ? operation inside a polonius! or polonius_loop! block.

• Only Result and Option are supported (e.g., no ControlFlow).

See polonius! for more info.

Example

• use {
      ::polonius_the_crab::prelude::*,
      ::std::collections::HashMap,
  };
  
  enum Error { /* … */ }
  
  fn fallible_operation (value: &'_ i32)
    -> Result<(), Error>
  {
      // …
  }
  
  fn get_or_insert (
      mut map: &'_ mut HashMap<i32, i32>,
  ) -> Result<&'_ i32, Error>
  {
      polonius!(|map| -> Result<&'polonius i32, Error> {
          if let Some(value) = map.get(&22) {
              // fallible_operation(value)?;
              polonius_try!(fallible_operation(value));
              polonius_return!(Ok(value));
          }
      });
      map.insert(22, 42);
      Ok(&map[&22])
  }