Tracking Issue for RFC 3325: unsafe attributes

[traviscross]

This is a tracking issue for RFC 3325: unsafe attributes

RFC: rust-lang/rfcs#3325
Issues: F-unsafe_attributes `#![feature(unsafe_attributes)]`

The feature gate for the issue is #![feature(unsafe_attributes)].

For a table showing the attributes that were considered to be included in the list to require unsafe, and subsequent reasoning about why each such attribute was or was not included, see this comment here

About tracking issues

Tracking issues are used to record the overall progress of implementation. They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions. A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature. Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.

Steps

• Accept the RFC.
  • unsafe attributes rfcs#3325
• Implement in nightly Rust 2024.
  • Parse unsafe attributes #124214
  • Add hard error and migration lint for unsafe attrs #126177
  • More unsafe attr verification #127543
• Implement migration lints.
  • Add hard error and migration lint for unsafe attrs #126177
• rustfmt support
• N/A: Add documentation to the dev guide.
  • See the instructions.
• Add documentation to the reference.
  • Add some basic docs for unsafe attrs reference#1539
  • 2024: Add unsafe attribute differences reference#1579
• Add documentation to the edition guide.
  • Add 2024 unsafe attributes. edition-guide#308
• N/A: Add formatting for new syntax to the style guide.
  • See the nightly style procedure.
• Stabilize in all editions.
  • Stabilize unsafe_attributes #128771
• Ensure ready for Rust 2024 stabilization.

Unresolved Questions

• Different lint staging. The lint on using existing unsafe attributes like no_mangle outside unsafe(...) could be staged in various ways: it could be warn-by-default to start or we wait a while before to do that, it could be edition-dependent, it might eventually be deny-by-default or even a hard error on some editions -- there are lots of details here, which can be determined later during the process.

Implementation history

• Parse unsafe attributes #124214
• More unsafe attr verification #127543

cc @RalfJung @carbotaniuman @rust-lang/style

This issue has been assigned to @carbotaniuman via this comment.

[traviscross]

@rustbot assign @carbotaniuman

@carbotaniuman has volunteered to own this item to get it over the line for the edition. Huge thanks for that.

[traviscross]

@rustbot labels +I-style-nominated

There's probably not a lot for T-style to do here, but strictly speaking, this is a kind of new syntax, so it may be worth at least a short discussion for visibility.

[traviscross]

@rustbot labels -I-style-nominated

We discussed this in the style team meeting today and confirmed that this will not require any special handling or changes to the style guide.