Dafny also originated in MS and initially targeted .NET.

https://www.microsoft.com/en-us/research/project/dafny-a-lan...

I believe, Nim also has this functionality, although, it uses the [0]Z3Prover tool with a nim frontend [1]DrNim for proving.

[0]https://github.com/Z3Prover/z3

[1]https://nim-lang.github.io/Nim/drnim.html

> Love the type checking, which I think is better than Rusts. But since I think Rust will win the market, I hope it improves.

Could you please elaborate on this? What specific stuff are you suggesting that F# does so well?

I'm in-experienced with Rust. So bit subjective.

F# uses algebraic types, and compiler can do pretty extensive type checking. I understand Rust also does this, it just seemed like Rust allows some options that make it not as complete. But, I'm not expert on Rust.