Illegal Instruction Promoting const panic!

[cramertj]

Playground link

#![feature(min_const_fn, const_panic)]

const fn foo() {
    panic!("")
}

fn main() {
    let _: &'static () = &foo();
}

causes an illegal hardware instruction. cc @oli-obk

[OvermindDL1]

In debug mode, release mode, or both? I've seen this happen in release mode because it's undefined behaviour so an optimization pass kills it.

[matthiaskrgr]

According to the playground it happens for both, release and debug.

[oli-obk]

Yea we need to solve this before stabilization. When failing to generate the promoted static we can insert an actual panic.

[oli-obk]

This has been circumvented by #53851