bug: normalize_comments eats single line comments in rust examples
Open
Nobody has claimed this yet.
A-comments
C-bug
I-unexpectedly-removes-code
only-with-option
S-has-mcve
UO-normalize_comments
- Dominant language
- Rust
- Stars
- 7k
- Forks
- 1.1k
- Avg merge
- 2d 13h
- Merged PRs (30d)
- 24
Description
When normalize_comments sees rust examples in the comments, it currently removes the comments. It should not.
❯ cargo +nightly --version
cargo 1.90.0-nightly (930b4f62c 2025-06-28)
❯ cargo +nightly fmt -- --config normalize_comments=true
Input
/*!
```
// foo
```
*/
/**
```
// bar
```
*/
struct Bar;
/*
```
// baz
```
*/
Output
//! ```
//! foo
//! ```
/// ```
/// bar
/// ```
struct Bar;
// ```
// baz
// ```
Expected
//! ```
//! // foo
//! ```
/// ```
/// // bar
/// ```
struct Bar;
// ```
// // baz
// ```
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 by reproducing the issue with cargo +nightly fmt -- --config normalize_comments=true using the Rust examples in this report, then trace the normalize_comments handling in rustfmt. Done means single-line comments inside Rust code blocks remain present in the formatted output for inner, outer, and regular block comments.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- tooling
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 68/100