zlacker

Couple options:

1. Have a constraint on T that lets you return some sort of placeholder. For example, if you've got an array of u8, maybe every read past the end of the array returns 0.

  fn bar<T: Default>() -> T {
    if let Some(t) = foo() {
      t
    } else {
      eprintln!("programmer error, foo() returned None!");
      Default::default()
    }
  }

2. Return a `Option<T>` from bar, as you describe.

3. Return a `Result<T, BarError>`, where `BarError` is a struct or enum describing possible error conditions.

  #[non_exhaustive]
  enum BarError {
    FooIsNone,
  }
  
  fn bar<T>() -> Result<T, BarError> {
    if let Some(t) = foo() {
      Ok(t)
    } else {
      eprintln!("programmer error, foo() returned None!");
      Err(BarError::FooIsNone)
    }
  }