which rule is responsible for adding a line break ...

# ktlint

[Peter]

which rule is responsible for adding a line break before ->

[Peter]

I'm wondering, if it's possible to format like so

[David Kubecka]

Try to format it as you want and then run ktlint manually. The error report should include the violated rule.

[Peter]

I guess trailing comma stuff https://github.com/pinterest/ktlint/issues/1519