Tracking Issue for `NonZero` trait

[nvzqz]

Feature gate: #![feature(nonzero_trait)]

This is a tracking issue for adding a NonZero trait to core::num, which includes an associated scalar type and a safety requirement.

Public API

// core::num

pub unsafe trait NonZero: Sealed {
    type Scalar;
}

unsafe impl NonZero for NonZero{U,I}{8,16,32,64,128,size} {
    type Scalar = {u,i}{8,16,32,64,128,size};
}

Steps / History

• Implementation: Create NonZero trait with primitive associated type #95155
• Final comment period (FCP)
• Stabilization PR

Unresolved Questions

• Should the associated type be named Scalar or something else, such as Primitive?

[leonardo-m]

(Generally I need the opposite: given an integral type tell me what's the corresponding NonZero type).

[dtolnay]

Superseded by #120257.