Github user bowenli86 commented on the issue:
https://github.com/apache/flink/pull/5112
@StephanEwen @greghogan ok, so looks like the rules of checkstype and
scalastyle are a bit different, that's why I misreported
`flink-streaming-scala`'s style checking is inactive.
scala style for subpackage `/experimental.scala` is automatically active
already. I did some tests and made sure that.---
