t5954.scala:36: error: class D should be placed directly in package A instead of package object A. Under some circumstances companion objects and case classes in package objects can fail to recompile. See https://issues.scala-lang.org/browse/SI-5954.
  case class D()
             ^
t5954.scala:35: error: object C should be placed directly in package A instead of package object A. Under some circumstances companion objects and case classes in package objects can fail to recompile. See https://issues.scala-lang.org/browse/SI-5954.
  object C
         ^
t5954.scala:34: error: trait C should be placed directly in package A instead of package object A. Under some circumstances companion objects and case classes in package objects can fail to recompile. See https://issues.scala-lang.org/browse/SI-5954.
  trait C
        ^
t5954.scala:33: error: object B should be placed directly in package A instead of package object A. Under some circumstances companion objects and case classes in package objects can fail to recompile. See https://issues.scala-lang.org/browse/SI-5954.
  object B
         ^
t5954.scala:32: error: class B should be placed directly in package A instead of package object A. Under some circumstances companion objects and case classes in package objects can fail to recompile. See https://issues.scala-lang.org/browse/SI-5954.
  class B
        ^
5 errors found