proc macro results in clippy treating a method starting with "r" as a raw string

[Byter09]

Summary

While upgrading to Rust 1.88.0 I tried using cargo clippy --fix, and suddenly couldn't compile anymore due to the issue described down below.

I sadly do not have the time to write a fully compiling minimal example (sorry 🥲), but I can provide the snippet.

The macro in question here comes from tracing_attributes version 0.1.26.

Lint Name

needless_raw_strings

Reproducer

I tried this code:

impl MyType {
    #[instrument(name = "run_event_machine", skip(self))]
    fn run(&mut self) {
    ...

I saw this happen:

error: unnecessary raw string literal
   --> src/queries/events/event_machine.rs:166:8
    |
166 |     fn run(&mut self) {
    |        ^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_raw_strings
    = note: `-D clippy::needless-raw-strings` implied by `-D clippy::restriction`
    = help: to override `-D clippy::restriction` add `#[allow(clippy::needless_raw_strings)]`
help: use a plain string literal instead
    |
166 -     fn run(&mut self) {
166 +     fn un(&mut self) {
    |

I expected to see this happen:
Nothing. This is a method.

Version

rustc 1.88.0 (6b00bc388 2025-06-23)
binary: rustc
commit-hash: 6b00bc3880198600130e1cf62b8f8a93494488cc
commit-date: 2025-06-23
host: x86_64-unknown-linux-gnu
release: 1.88.0
LLVM version: 20.1.5

Additional Labels

No response

[samueltardieu]

The reproducer could come as a repository on GitHub that we could compile.

[Byter09]

Hi, yes, I know. The issue isn't making one. The issue is time. This is something that came up during work, and I can't really take the time at the moment. The hot fix was to just expect the lint at that position and I was able to move on.

But I still wanted to at least make an issue so someone is aware that this happened. If I get the time after my current ticket I'll see if I can do it. I know it's not optimal but that was the best I could do. 😔

[Jarcho]

instrument is likely misusing quote_spanned to set the span of the string literal to that of the function's name. needless_raw_strings only checks that the test starts with r and doesn't contain backslashes or quotes.