builder > A.scala B.scala
compiling Set(A.scala, B.scala)
Changes: Map()
builder > A.scala
compiling Set(A.scala)
Changes: Map(trait A -> List(Changed(Definition(A.T))[type T changed from A.this.T to A.this.T flags: ]))
invalidate B.scala because it references changed definition [Changed(Definition(A.T))[type T changed from A.this.T to A.this.T flags: ]]
compiling Set(B.scala)
B.scala:2: error: type mismatch;
 found   : a.T
    (which expands to)  Long
 required: Int
  def x(a: A): Int = a.x
                       ^