[lmm]

Scala has implicit conversions but the IDEs highlight when they're happening, so they're not completely invisible.

To my mind Scala is a very unmagic language; very complex libraries are written for it, but they're never magic, they're always ordinary Scala code and ordinary Scala features, just combined in clever ways. E.g. typeclasses are a language feature in Haskell, but in Scala they're just a pattern that you implement using implicit parameters. Actors and messages are a language feature in Erlang, but in Scala they're just a library with methods that you call. Type-level functions are a language feature in e.g. Idris, but in Scala (e.g. Shapeless) they're just a technique making use of implicit resolution.