It reminds me of Scala too, but I have no idea which started when. And of course both could have come up with this fairly independently. (After all it is the norm in functional style.)
Kotlin was started even as just a poor Scala clone. (Because JetBrains didn't manage to get a working Scala plugin for their IDE, so they thought it would be simpler to create their own "simpler" version of the language).
Kotlin was started even as just a poor Scala clone. (Because JetBrains didn't manage to get a working Scala plugin for their IDE, so they thought it would be simpler to create their own "simpler" version of the language).