Yes, all languages borrow from others. As I said, I think that Kotlin in particular was created to be a more palatable Scala alternative for Java Devs. I also find that Kotlin articles have this remarkable tendency to act like so many of the features of Kotlin were new to Kotlin. In the case of your article, your title is what Rust could learn from Kotlin. But almost everything in it is stuff that Kotlin got from other languages, especially Scala. A more accurate title might have been “What Rust can learn from Scala and Kotlin” with five bullet points for Scala and one for Kotlin. Of course, some of the bullet points could be pushed further back, but my main issue is that the way the article is couched really does imply that Kotlin is where these things started.

If you focused on null safety, that was something Kotlin did in a new way that was significant, but that doesn’t apply to Rust. And Rust certainly brings in a lot of new elements that really hadn’t been done before.