Formatting adds erroneous comma at end of struct update syntax when missing comma before ..
Nobody has claimed this yet.
- Dominant language
- Rust
- Stars
- 7k
- Forks
- 1.1k
- Avg merge
- 2d 13h
- Merged PRs (30d)
- 24
Description
Following up on https://github.com/rust-lang/rust/issues/104373, when using functional record update syntax, if a comma is missed before the ..Default::default(), rustfmt will then "helpfully" add a comma after the ..Default::default().
When you fix the error with the missing comma, you now have a different error ("no trailing commas after...") that the user did not make, as automatic formatting added a comma in its confusion.
I'm new to this project, but the new error enum variant proposed in https://github.com/rust-lang/rust/pull/104504 may be helpful to identify these cases.
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 reported functional record update case in rustfmt, with the comma omitted before ..Default::default(), and inspect the formatter path that handles this syntax. Done means rustfmt does not add an erroneous trailing comma, so fixing the original missing comma does not create a second error.
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
- Mostly clear
- Newbie friendliness
- 35/100