Description
The new lint for excess semicolons (#62984) has some weird behaviour when the lint is triggered inside an async function that is transformed using a procedural macro.
Rustc version: 1.39.0-nightly (9b91b9c 2019-08-26)
Compiling this:
#[tokio::main]
async fn main() -> Result<(), ()> {
let mut workers = 5;;
Ok(())
}gives this output:
warning: unused variable: `workers`
--> examples/test.rs:1:1
|
1 | #[tokio::main]
| ^ help: consider prefixing with an underscore: `_workers`
|
= note: `#[warn(unused_variables)]` on by default
warning: variable does not need to be mutable
--> examples/test.rs:1:1
|
1 | #[tokio::main]
| ^ help: remove this `mut`
|
= note: `#[warn(unused_mut)]` on by default
note how the spans are all targeting the procedural macro instead of the correct line.
If I remove the procedural macro or if I remove the excess semicolon, the spans are fine. This leads me to believe that it's an error in the lint, not in the macro, but maybe I'm wrong.