Tracking Issue for `cfg(overflow_checks)`

[AngelicosPhosphoros]

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

It allows write code that detects if compiler emits code for integer overflow checks similarly to how cfg(debug_assertions) allow to detect if debug assertions enabled.

Example:

#[cfg(overflow_checks)]
#[track_caller]
fn cast(v: i64)->u32{
    v.try_into().unwrap()
}

#[cfg(not(overflow_checks))]
fn cast(v: i64)->u32{
    v as _
}

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 feature.
• Adjust documentation (see instructions on rustc-dev-guide)
• Stabilization PR (see instructions on rustc-dev-guide)

Unresolved Questions

Implementation history

#111096
rust-lang/reference#1355

[CAD97]

Note: this feature is observable on nightly without #![feature] via build scripts checking $CARGO_CFG_OVERFLOW_CHECKS. The env var isn't set for beta/stable, so this is fine, but imho still warrants mentioning here.