VampiricCompilerCrash.scala

object DeriveFamily {
  def minimal: Any = macro DeriveFamilyMacros.minimal
}

object DeriveFamilyMacros {
  class body(tree: Any) extends StaticAnnotation

  def bodyImpl(c: Context) = {
    import c.universe._

    val field = c.macroApplication.symbol
    val bodyAnn = field.annotations.filter(_.tree.tpe <:< typeOf[body]).head
    bodyAnn.tree.children.tail.head
  }

  def minimal(c: Context): c.Tree = {
    import c.universe._
    q"""object Foobar { val _x = "X"; @DeriveFamilyMacros.body(Foobar._x) def x: String = macro DeriveFamilyMacros.bodyImpl }; Foobar"""
  }
}

object Working {
  def x = {
    val foobar = DeriveFamily.minimal
    println(foobar.x)
  }

  x // Prints "X"
}

object NotWorking {
  val foobar = DeriveFamily.minimal
  println(foobar.x)
  /*
  [trace] Stack trace suppressed: run last common/test:compileIncremental for the full output.
  [error] (common/test:compileIncremental) java.lang.IllegalArgumentException: Could not find proxy for var Foobar$module: runtime.VolatileObjectRef in List(variable Foobar$module, value foobar, Object NotWorking, package <root>) (currentOwner= value <local NotWorking> )
  */
}