1.99 beta crater regression: use of an internal attribute

[theemathas]

This regression was found by the 1.99 crater run.

[INFO] [stdout] error[E0658]: use of an internal attribute
[INFO] [stdout]    --> src/main.rs:165:5
[INFO] [stdout]     |
[INFO] [stdout] 165 |     #[sequential]
[INFO] [stdout]     |     ^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: the `rustc_test_entrypoint_marker` attribute is an internal implementation detail that will never be stable
[INFO] [stdout]     = note: this error originates in the attribute macro `sequential` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0658`.

Affects 9 crates. The errors point to #[sequential], #[debug], or #[test].

• https://crater-reports.s3.amazonaws.com/beta-1.99-4/1.99.0-beta.1/gh/Haider-Ali-DS.simple-axum-notes-api/log.txt
• https://crater-reports.s3.amazonaws.com/beta-1.99-4/1.99.0-beta.1/gh/PRO-2684.Candy-Pile/log.txt
• https://crater-reports.s3.amazonaws.com/beta-1.99-4/1.99.0-beta.1/gh/kcui5.redlib/log.txt
• https://crater-reports.s3.amazonaws.com/beta-1.99-4/1.99.0-beta.1/gh/open-rust.macro-log/log.txt
• https://crater-reports.s3.amazonaws.com/beta-1.99-4/1.99.0-beta.1/gh/seagleNet.permfixer/log.txt
• https://crater-reports.s3.amazonaws.com/beta-1.99-4/1.99.0-beta.1/reg/etest-tests-0.3.0/log.txt
• https://crater-reports.s3.amazonaws.com/beta-1.99-4/1.99.0-beta.1/reg/lambda-otel-lite-0.19.1/log.txt
• https://crater-reports.s3.amazonaws.com/beta-1.99-4/1.99.0-beta.1/reg/libreddit-0.30.1/log.txt
• https://crater-reports.s3.amazonaws.com/beta-1.99-4/1.99.0-beta.1/reg/sequential-test-0.2.4/log.txt

[cyrgani]

reduction for sequential-test:

extern crate proc_macro;
use proc_macro::TokenStream;

#[proc_macro_attribute]
pub fn sequential(_attr: TokenStream, item: TokenStream) -> TokenStream {
    item.to_string().parse().unwrap()
}

and

#[test]
#[x::sequential]
fn s1() {}

fn main() {}

[cyrgani]

bisects to #158854 (cc @jdonszelmann @JonathanBrouwer)