Really annoyed by the borrow checker? Use immutable data structures
    ... This is especially helpful when you need to write pure code similar to that seen in Haskell, OCaml, or other languages.

Are there any tutorials or books which take an immutable-first approach like this? Building familiarity with a functional subset of the language, before introducing borrowing and mutability, might reduce some of the learning curve.

I suspect Rust does not implement as many FP-oriented optimizations as GHC, so this approach might hit performance dropoffs earlier. But it should still be more than fast enough for learning/toy datasets.