Having a background in Haskell (and C) made me able to jump in and be productive in Rust within hours. And that's a language that is considered to have a steep learning curve.
Never used it in production either but I did use Haskell to ace some of my advanced computer science course work with less time and less lines of code than my peers.
I concur, for me the journey was:
Java -> Clojure -> Haskell -> Rust.
Each language introduced concepts that made it easier to learn the next. So far I've had jobs in all of those languages except for Rust, but that time will come too. I still prefer Haskell for everything that doesn't involve GUI's.
Never used it in production either but I did use Haskell to ace some of my advanced computer science course work with less time and less lines of code than my peers.