First-class suppressions support

[workingjubilee]

In general, the standard library often has benign "leaks", either because the platform APIs have a detectable leak and we have no control over them, or because we've allocated a few bytes somewhere to track something like thread info or a mutex. And this will change from version to version. We're trying to reduce them, but it's never our priority, the exact number of possible leaks is platform dependent, and we don't test them.

It would be nice if cargo valgrind made it easy to generate suppressions for these and reuse them, because, contra your documentation that people only need this for unsafe code, people do run it on perfectly safe programs.

[jfrimmel]

Thank you for this report. You're totally right and the standard library version 1.83 clearly shows, that this is desperately needed. A simple example can be found in even in this repository: cargo +stable-1.83 test fails due to the "leaks".

I'll have to design a way to get rid of such leak messages, as they are clearly non-actionable by the user (and totally fine as well).