field: Type /* Comment */ , /* Comment */ causes rustfmt to introduce breaking comma
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C-bug
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- Rust
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Description
While strange,
struct Struct {
field: String /* Comment */ , /* Comment */
}
compiles.
When hit with cargo fmt it's transformed into
struct Struct {
field: String, /* Comment */ , /* Comment */
}
which fails to compile.
Observed on rustfmt 1.5.1-nightly (2022-06-30 7425fb2) and rustfmt 1.4.38-stable (db9d1b2 2022-01-20).
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
Reproduce the issue with the Rust struct shown in the report and run cargo fmt using the affected rustfmt versions. Trace the formatting path for fields and comments; done means the formatter preserves valid Rust and does not introduce the extra comma before the comment.
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
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 45/100