firefox/third_party/rust/thiserror/tests/ui/raw-identifier.rs

use thiserror::Error;

#[derive(Error, Debug)]
#[error("error: {r#fn}")]
pub struct Error {
    r#fn: &'static str,
}

fn main() {
    let r#fn = "...";
    let _ = format!("error: {r#fn}");
}