Tracking Issue for generic `NonZero`

[reitermarkus]

Feature gate: #![feature(generic_nonzero)]

This is a tracking issue for replacing the distinct NonZero* types with a generic NonZero<T> type. This allows using NonZero with FFI type aliases instead of having weird type names like NonZero_c_ulonglong.

This replaces the following tracking issues:

• Tracking Issue for NonZero trait #95157
• Tracking Issue for NonZero_c_* integers #82363

Public API

use core::num::{NonZero, NonZeroU8};

assert_eq!(NonZero::new(33u8), NonZeroU8::new(33));

Steps / History

• Initial implementation attempt: Add generic NonZero type. #100428
• Consolidate all associated items on the NonZero integer types into a single impl block per type #118665
• Add private NonZero<T> type alias. #119990
• Manually implement derived NonZero traits. #120160
• Switch NonZero alias direction. #120165
• Use Self in NonZero* implementations. #120244
• Make NonZero constructors generic. #120521
• Use transmute_unchecked in NonZero::new. #120809
• Make NonZero::get generic. #120563
• Use generic NonZero internally. #120486
• Make other methods generic. (optional, can happen after stabilization)
  • Implement NonZero traits generically. #121241
• Refactor trait implementations in core::convert::num. #121277
• Use generic NonZero everywhere in library. #121454
• Use generic NonZero in tests. #121461
• Make ZeroablePrimitive trait unsafe. #121850
• Final comment period (FCP)¹
  • Move generic NonZero rustc_layout_scalar_valid_range_start attribute to inner type. #121885
• Stabilization
  • Stabilize generic NonZero. #124230
• Generic NonZero post-stabilization changes. #124587

Unresolved Questions

• None yet.

Footnotes

1. https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩

[reitermarkus]

@dtolnay, given the documentation issue, making NonZero::new and other constructors generic can really only be done during/after stabilization, so the only blocker I can see right now is stabilization itself. Can this enter FCP, or do we want to wait for #120486?