A.scala

def foo() { println("foo") }
class A {
  def bar() {
    foo
  }
}
new A().bar()

Main.scala

object Main {
  def main(args: Array[String]): Unit = {
    final class $anon extends scala.AnyRef {
      def foo(): Unit = scala.this.Predef.println("foo");
      class A {
        def bar(): Unit = $anon.this.foo()
      }
      new $anon.this.A().bar()
    }
    new $anon();
  }
}