Braces are removed from single-item import in macro where they are required
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A-macros
C-bug
- Dominant language
- Rust
- Stars
- 7k
- Forks
- 1.1k
- Avg merge
- 2d 13h
- Merged PRs (30d)
- 24
Description
In a macro that takes a path as an argument:
macro_rules! get_msg {
($module:path) => {
let message = {
use $module::{MESSAGE}; // note the (usually unnecessary) brackets
MESSAGE
};
println!("{}", message);
};
}
The braces around MESSAGE are required, and the code fails to compile without them. However, rustfmt removes them.
Playground: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=ca5ee49a37c35354f67d82d6303c7f5a
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the linked Rust Playground example and reproduce the formatting change using rustfmt. Trace the formatter's handling of the single-item use $module::{MESSAGE}; inside the macro, then verify that the braces are preserved and the formatted example still compiles.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- tooling
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100