Does writing `private[this] def` make sense in terms of performance-to-noise ratio compared to just `private def`? I understand it makes a difference regarding `private[this] val` over `private val` because the former allows scalac to create an actual field. But perhaps for `def` it makes no difference? Finally, how about `private[this] var`?

There is a [very similar question](https://stackoverflow.com/questions/9698677/privatethis-vs-private), but it does not contain specific statements regarding performance.