rust-lang / rust-lang/rust

Tracking Issue for `feature(cfg_ub_checks)` and `-Zub-checks`

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C-tracking-issue
Dominant language
Rust
Stars
119k
Forks
16.2k
PR merge metrics
PR metrics pending

Description

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

This feature allows writing code that detects if the compiler will emit UB checks, simlar to how cfg(debug_assertions) detects if debug assertions are enabled.

We also track the -Zub-checks flag here; that should eventually become -Cub-checks similar to -Coverflow-checks.

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
Unresolved Questions
Implementation history

https://github.com/rust-lang/rust/pull/123411

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the implementation history in PR #123411 and the cfg_ub_checks feature gate. Read the linked rustc-dev-guide documentation and stabilization instructions; done means completing the documentation work and preparing the stabilization PR, with any unresolved questions addressed.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
compilers
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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