From<bool> and Bounded's invariant for signed N = 1

[Younes Akhouayri <git@younes.io>]

Hi,

There seems to be an invariant violation in the generic From<bool>
implementation for Bounded.

As I understand it, Bounded<i8, 1> can represent only -1 and 0, while
i8::from(true) produces 1. However, this safe code is accepted:

let value: Bounded<i8, 1> = true.into();
let _raw: i8 = *value;

Bounded::<i8, 1>::try_new(1) rejects the same value, but From<bool>
passes it directly to the unsafe __new() constructor. The resulting
Bounded value violates the invariant relied upon by Deref, whose
failure branch calls unreachable_unchecked().

Am I missing an intended constraint on this conversion? If not, it
seems the signed N = 1 case needs to be excluded or handled
differently.

Any thoughts?

Thanks,
Younes