Nested class shadowing in "override" position

[eed3si9n]

Ref scala/scala#8705 / scala/bug#8353

steps

Compile using the latest 2.13.x nightly (https://scala-ci.typesafe.com/job/scala-2.13.x-integrate-community-build/3267/) or 2.13.2 when it comes out.

sbt> set ThisBuild/resolvers += "scala-integration" at "https://scala-ci.typesafe.com/artifactory/scala-integration/"
sbt> ++2.13.2-bin-53ba87a!
sbt> compile

problem

Community Builds discovered there are some nested classes in "override" position.

[treehugger] [warn] /home/jenkins/workspace/scala-2.13.x-integrate-community-build/target-0.9.16/project-builds/treehugger-ff89fa5e75415075385d291e902d1a75e464a1c1/library/src/main/scala/treehugger/TreePrinters.scala:37: shadowing a nested class of a parent is deprecated but class TreePrinter shadows trait TreePrinter defined in trait TreePrinters; rename the class to something else

expectation

Nothing for now, but consider renaming them when you can.