Clippy told me to write an invalid line

[thomas-daniels]

I have this Rust function (the get attribute and Template come from the web framework Rocket):

#[get("/")]
fn index() -> Template {
    Template::render("home/index", empty_hashmap())
}

When running Clippy over my code, it said something about this function:

 --> src\controllers\home.rs:4:1
  |
4 | #[get("/")]
  | ^^^^^^^^^^^ help: consider taking a reference instead: `&#[get("/")]`
  |
  = note: #[warn(needless_pass_by_value)] on by default
  = help: for further information visit https://github.com/Manishearth/rust-clippy/wiki#needless_pass_by_value

Alright, so I did what Clippy told me:

&#[get("/")]
fn index() -> Template {
    Template::render("home/index", empty_hashmap())
}

However, the compiler wasn't too happy with that:

error: expected item, found `&`
 --> src\controllers\home.rs:4:1
  |
4 | &#[get("/")]
  | ^

Is it a bug in Clippy that it suggests me to write this line? Or is it a problem from Rocket, or just my misunderstanding?

[oli-obk]

This is actually a rustc bug: rust-lang/rust#43268

We have an issue open in this repo at #1885, so I'll close this issue in favour of the other one.