Macro-powered structural types

gistfile1.scala

import scala.annotation.StaticAnnotation
import scala.reflect.macros.Macro
import language.experimental.macros

class body(tree: Any) extends StaticAnnotation

trait Macros extends Macro {
  import c.universe._

  def selFieldImpl = {
    val field = c.macroApplication.symbol
    val bodyAnn = field.annotations.filter(_.tpe <:< typeOf[body]).head
    bodyAnn.scalaArgs.head
  }

  def mkObjectImpl(xs: c.Tree*) = {
    val kvps = xs.toList map { case q"${_}(${Literal(Constant(name: String))}).->[${_}]($value)" => name -> value }
    val fields = kvps map { case (k, v) => q"@body($v) def ${TermName(k)} = macro Macros.selFieldImpl" }
    q"class Workaround { ..$fields }; new Workaround{}"
  }
}

object mkObject {
  def apply(xs: Any*) = macro Macros.mkObjectImpl
}

=================

object Test {
  def main(args: Array[String]) = {
    val foo = mkObject("x" -> "2", "y" -> 3)
    println(foo.x)
    println(foo.y)
    // println(foo.z) => will result in a compilation error
  }
}