Tracking Issue for Rust 2024: Cargo remove implicit features

[traviscross]

This is a tracking issue for the Rust 2024-relevant parts of:

• RFC: Remove implicit features in a new edition rfcs#3491
• Tracking Issue for remove-implicit-feature RFC 3491 cargo#12826

Most things should go in the Cargo tracking issue This issue is for tracking readiness for the Rust 2024 edition.

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

• Implement in nightly Rust 2024.
• Implement (unimplement) migration lints.
  • Unused dependencies cleanup cargo#13778
  • fix: Remove implicit feature removal cargo#14630
• N/A: Add documentation to the dev guide.
  • See the instructions.
• N/A: Add documentation to the reference.
  • See the instructions.
• Add documentation to the edition guide.
  • 2024: Document cargo changes edition-guide#301
• Remove documentation from the edition guide.
  • Remove cargo-remove-implicit-features edition-guide#324
• Update documentation to the cargo guide.
  • Update feature docs for no implicit features in 2024 cargo#14011
• Ensure ready for Rust 2024 stabilization.

Related

• 2024 implicit feature migration deletes dependency features cargo#14010
• Bad error message when a weak dep features's depedency is an unused optional dependency cargo#14015
• Bad error message when a strong dep features's depedency is an unused optional dependency cargo#14016

cc @rust-lang/cargo @epage @Muscraft

[ehuss]

Note: This is at risk for not being included in the edition due to issues with the implementation (rust-lang/cargo#14016 particularly).

[ehuss]

The cargo team has decided to drop this from the 2024 edition. There are some implementation issues, and we feel that there is just too much risk trying to resolve it at such a late date. Further status updates will happen on rust-lang/cargo#12826.