Correct by Construction Non-Empty List

This package exposes a type NonEmpty<T> with a data representation that guarantees non-emptiness statically:

struct NonEmpty<T>(T, Vec<T>)

The library is meant to have an interface similar to std::vec::Vec:

use nonempty::NonEmpty;

let mut l = NonEmpty::new(42);

assert_eq!(l.first(), &42);

l.push(36);
l.push(58);

let v: Vec<i32> = l.into();
assert_eq!(v, vec![42, 36, 58]);