SwiftLint format with Swift 6.1 trailing commas feature changes closing parenthesis indentation

[ebgraham]

New Issue Checklist

• [x] I've Updated SwiftLint to the latest version.
• [x] I've searched for existing GitHub issues.

Bug Description

When using the new Swift 6.1 support for trailing commas, SwiftLint indents the closing parenthesis rather than keep it at the expected non-indented level.

// with trailing comma
let a = CGRect(
    x: 0,
    y: 0,
    width: 100,
    height: 100,
    )

// without trailing comma
let a = CGRect(
    x: 0,
    y: 0,
    width: 100,
    height: 100
)

Environment

• SwiftLint version 0.59.0
• Xcode version (n/a)

[SimplyDanny]

Which command are you running and what is the configuration in use?

[ebgraham]

Which command are you running and what is the configuration in use?

using swiftlint --fix --format with an empty configuration file.

[mildm8nnered]

I can repro this

[Marvae]

I'm interested in taking a look at this issue. Is anyone currently assigned to it or actively working on it? Thanks!

[SimplyDanny]

SwiftLint is entirely relying on SourceKit to format code. With the Swift 6.1.2 toolchain that comes bundled with Xcode 16.4 I see the behavior, too. This is an upstream issue we cannot fix in SwiftLint.