builder > A1.scala A2.scala A3.scala
compiling Set(A1.scala, A2.scala, A3.scala)
Changes: Map()
builder > A1.scala
compiling Set(A1.scala)
Changes: Map(object A -> List(Added(Definition(A.x_$eq)), Changed(Definition(A.x))[value x changed to variable x]))
invalidate A2.scala because it references changed definition [Changed(Definition(A.x))[value x changed to variable x]]
compiling Set(A2.scala)
A2.scala:2: error: stable identifier required, but A.x found.
  import A.x.y
           ^
A2.scala:3: error: not found: value y
  val z = y
          ^