This is the real answer! You can understand the abstract idea and not know the trivia. If the person doesn't know scala, then they won't know these. Find something they do know and expand on that or relate it to the scala and then ask "So why would you use this"

They're still better than the x = x + (y+=(++x)) things I've encountered in school assignments. I've always wondered why knowledge of what ought to be akin to undefined behavior is a good thing, excepting "idioms" like

  do {...} while ((line = file.read()) != 0)

which one no longer understands after a week away from the language robs you of a short-term mental model of the language's quirks and evaluation strategies and what-have-you.