I don’t know any detailed comparison but knowing Scala I found some parts of Rust rather easy like closures and traits (although Scala traits are not a 1:1 equivalent for Rust’s traits).
I have spoken to several Scala developers who are really excited about Rust.
I think the hardest part will be understanding the Borrow Checker and the memory safety as this is mostly hidden from Scala developers because of the JVM (that does not mean a Scala developer shouldn’t think about memory usage, of course!).
I recommend reading through the Rust book on the Rust website, it explains most of the language very well and you can see how it compares to Scala.
I like Scala a lot. Rust is the first language since I learned Scala several years ago that I find really interesting, mostly thanks to the combination of functional features with all the low level stuff, good performance and most important memory safety.