I would question your assertion that Rust is functional. Rust does have a lot of features that a lot of other functional languages have, Algebraic Data Types,

I would question your assertion that Rust is functional. Rust does have a lot of features that a lot of other functional languages have, Algebraic Data Types, closures. But one thing Rust misses is purity. Although you do have to be explicit about when you are mutating state, I think it would be very hard to actually write a program that doesn't, and it certainly wouldn't make for idiomatic Rust code. I guess we are going into the definition of what makes a language functional. Rust is a great language and it does attempt to solve the same sort of problems that functional languages solve - multi threading, no surprising mutations.. It just uses a different paradigm to functional in order to solve them.