gistfile1.txt

  object Test extends EmbeddedControls {
    
    case class MyRow(args: List[(String, Any)]) extends Row[Rep]
  
    override def __new[T](args: (String, Any)*): T =  MyRow(args.toList).asInstanceOf[T]
    
    trait Rep[x]
    val foo: Rep[Row[Rep] { val xx: Int; val yy: String }] = (new Row[Rep] { val xx = 23; val yy = "y" }).asInstanceOf[Rep[Row[Rep] { val xx: Int; val yy: String }]]
    
  }
  println(Test.foo.xx)

//compiler error:

[error] /Users/grek/scala/lms-sandbox/src/Main.scala:158: value xx is not a member of Main.Test.Rep[Main.Test.Row[Main.Test.Rep]{val xx: Int; val yy: String}]
[error]   println(Test.foo.xx)
[error]                    ^
[error] one error found