err method

Option<E> err()

Converts this Result<T, E> into an Option<E>, discarding the held value if this is Ok.

Returns:

• Some<E> if this Result is Err<T, E>.
• None<E> if this Result is Ok<T, E>.

See also: Rust: Result::err()

Implementation

Option<E> err() {
  return switch (this) {
    Ok() => None(),
    Err(:E e) => Some(e),
  };
}