message: Use an expect instead of directly panicking
diff: @@ -542,12 +542,12 @@ impl<'a, 'cfg> DrainState<'a, 'cfg> {
  // Note that this pops off potentially a completely
  // different token, but all tokens of the same job are
  // conceptually the same so that's fine.
  - if let Some(rustc_tokens) = self.rustc_tokens.get_mut(&id) {
  + let rustc_tokens = self
  + .rustc_tokens
  + .get_mut(&id)
  + .expect("no tokens associated");
  self.tokens
  .push(rustc_tokens.pop().expect("rustc releases token it has"));
  - } else {
  - panic!("This job does not have tokens associated with it");
  - }
  }
  }
  