It would be nice to optionally generate `CProjection`, `CRow` and `CShape` using whitebox macro. For experimentation, I tried just moving `CRow` in a structural type (yet without a macro), but that failed with a type error. Any idea why?
```
val t = new{
  case class CRow(p: Pair[Int,String], b: BRow)
}
import t.CRow
```
@xeno-by @szeiger