REPL version sample code inspired by http://www.ne.jp/asahi/hishidama/home/tech/scala/trait.html#h_source_split

scope.repl.scala

Welcome to Scala version 2.9.0.1 (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_26).
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scala> trait scope {
     |   class A extends AnyRef with Z {
     |     def aaa() = zzz2()
     |     def aaa2() = 100
     |   }
     |   trait Z {self: A =>
     |     def zzz() = aaa2()
     |     def zzz2() = 22
     |   }
     | }
defined trait scope

scala> object M extends scope {
     |   def main(args: Array[String]) {
     |     val a = new A
     |     println(a.aaa() + a.zzz())
     |   }
     | }
defined module M

scala> M.main(Array())
122