[ER] cfg(overflow_checks)

[leonardo-m]

An enhancement request discussed here:
https://users.rust-lang.org/t/detecting-overflow-checks/67698/

(That thread also contains a hacky solution by Yandros).

I propose to add a config like this:

#[cfg(overflow_checks)]

I would like to use it to enable/disable lines of code that perform safe unsafe "as" casts replacing them with casts when I compile with debug builds or with release builds compiled with "-C overflow-checks".

[leonardo-m]

@rustbot modify labels: C-enhancement

[hkratz]

@rustbot label A-attributes T-compiler

[schuelermine]

I’d also be interested in this.

[AngelicosPhosphoros]

Tracking issue: #111466