tracing::instrument doesn't work for -> ! on stable

[oriongonza]

fn main() {}

#[tracing::instrument]
fn foo() -> ! {
    loop {}
}

Fails with

error[E0658]: the `!` type is experimental
 --> src/main.rs:4:13
  |
4 | fn foo() -> ! {
  |             ^
  |

[kaffarell]

This is not related to tracing. The never-type has been reverted for quite some time: rust-lang/rust#67224

[oriongonza]

never type in return position has been stable for a long time: playground link

[kaffarell]

https://doc.rust-lang.org/std/primitive.never.html

[oriongonza]

My previous comment didn't link to anything useful. Oops :P
Corrected link

[kaffarell]

The never type is still experimental, the fact that it works in the return position is a hack AFAICT rust-lang/rust#35121 (comment).