Raw identifier not supported in the `display` attribute about snafu HOT 8 CLOSED

Both the fact that it doesn't work as written, and that the error message is rendered without a source line of code, are compiler bugs. The error message should be getting placed as:

error: expected expression
 --> src/main.rs:5:27
  |
5 |     #[snafu(display("{}", r#type))]
  |                           ^^^^^^

The root cause for both is rust-lang/rust#43081.

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I also would suggest to improve the error message in this case, because I have no clue what's going on under the hood ^^

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The problem is that the arguments to #[snafu(display)] are expected to be a comma-separated list of expressions, but it appears that r#type isn't considered one...

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"Found ini the field" might not be correct @shepmaster. It's more that I know a lot of proc macros stumble across that, e.g. rwf2/Rocket#881.
I bet there are a lot more crates affected.

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I've filed dtolnay/syn#628 as I don't think this is my fault. In the meantime, try this workaround:

#[snafu(display = r#"("{}", r#type)"#)]
Oc { r#type: String }

While this form is intended to support versions of Rust before 1.34, it also switches to completely using syn's string-based parsing for this value, which does work.

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improve the error message in this case,

This would be difficult as the error message comes directly from syn.

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Hey @shepmaster,

rocket solved the issue in rwf2/Rocket@97f6bc5 maybe it is something snafu can adopt?

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This may have magically fixed itself in the intermediate time:

% cat examples/raw.rs
use snafu::Snafu;

#[derive(Debug, Snafu)]
enum Error {
    #[snafu(display("{}", r#type))]
    Oc { r#type: String }
}

fn main() {}

% cargo build --example=raw
    Finished dev [unoptimized + debuginfo] target(s) in 0.01s

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