macro for: val foo: Foo = new Foo(bar)

gistfile1.scala

  // val foo: Foo = new Foo(bar)
  private[this] def declareRuntime: Tree = {
    val runtimeClass = context.mirror.staticClass(classOf[Foo].getName)
    ValDef(
      Modifiers(),
      newTermName("foo"),
      TypeTree(runtimeClass.asType),
      Apply(
        Select(
          New(Ident(runtimeClass)),
          newTermName("<init>")),
        List(
          Select(
            context.prefix.tree,
            newTermName("bar")))))