[dfgdghdf]

Rust is influenced by OCaml but has lots of C++ concepts thrown in too. I don't think it makes sense to be choosing between OCaml/F# and Rust since they are so different. If you need the performance characteristics of Rust, then the choice is made for you (and you should also consider modern C++). If not, then the borrow checker is probably a burden that you don't need.

Maybe I'm missing something. Under what use-cases would someone be choosing between OCaml/F# and Rust?

[galangalalgol]

I don't think I ever would, I just knew they had common heritage and wondered if that was evident to the developer. I've been a professional c++ dveloper for the last 18 years and I've got a couple small projects now that we are using rust for. I know enough to modify rust or fix bugs but not to create an idiomatic design in it. If I don't need the speed I am usually prototyping so I use matlab. If I don't the speed and I'm not prototyping I use python, but that isn't often. I think Julia might end up having a spot in that range of options but c#/java isn't enough faster than python or enough easier to develop than c++/rust for me to consider it unless I need to use existing code.