[SPARK-33499] Enable `-Wunused:imports` in Scala 2.13 SBT

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Not A Problem
• Affects Version/s: 3.1.0
• Component/s: Build

Environment

Scala 2.13 think this is a unused import but Scala 2.12 compile failed without this import, so comments -Wunused:imports in Scala 2.13 and left a TODO in this pr

 

• Assignee: Unassigned
• Reporter: Yang Jie
• Created: 20/Nov/20 10:49
• Updated: 06/Dec/20 01:03
• Resolved: 06/Dec/20 01:03

Description

As the image, Scala 2.13 think `scala.language.higherKinds` is a unused import, }}but Scala 2.12 compile failed without this import, so comments {{-Wunused:imports in Scala 2.13 and left a TODO, 

we should enabled `-Wunused:imports` when Scala 2.12 is no longer supported.