The 2021 panic macro no longer works in `const` functions

[AaronKutch]

I encountered one issue when trying to migrate my crates to edition 2021. This no longer compiles:

#![feature(const_panic)]

pub const fn f() {
    panic!("important info");
}

I understand that this requires a nightly feature to observe, but const_panic was really close to stabilizing and I use this in a lot of places. Is it possible to adjust the underlying format_args to be const with a static string input, or is there something else I should use? I don't want to go back to using the weird out-of-bounds indexing hack when trying to convey messages from a const function.

[inquisitivecrystal]

This is a known problem, unfortunately. It appears to be a result of the changes made to the panic macro to standardize its behavior.

[fee1-dead]

See #86998