Unstable Book: const_caller_location leads to a closed tracking issue

[ArekPiekarz]

In Unstable Book the section const_caller_location leads to a closed tracking issue #47809 about a general caller tracking. There is a forked new issue about tracking callers for closures, but it seems unrelated to working in const functions.

This functionality is still not stabilized, because trying to use it like this:

#[track_caller]
const fn foo() -> &'static std::panic::Location<'static> {
    std::panic::Location::caller()
}

gives error:

error: `std::panic::Location::<'a>::caller` is not yet stable as a const fn
 --> src/lib.rs:3:5
  |
3 |     std::panic::Location::caller()
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: add `#![feature(const_caller_location)]` to the crate attributes to enable

Thus it looks like const_caller_location should have its own tracking issue.

[tesuji]

You could make this issue an tracking issue for that feature.
Could you rename the issue and make a PR to change this line ?

rust/library/core/src/panic.rs

Line 235 in b1d092c

#[rustc_const_unstable(feature = "const_caller_location", issue = "47809")]

[ArekPiekarz]

Thanks for the suggestion, I'll create another issue as tracking so I don't have to edit this one and so this conversation does not look out of place, then make a PR.