“Why was Rust chosen for Libra?” in congressional hearing [video]
Congressman:  I was really surprised about the Rust language. So my first question is, why was the Rust language chosen as the implementation language for Libra? Do you believe it's mature enough to handle the security challenges that will affect these large cryptocurrency transactions?<p>Facebook:  [We will own & control the code.]<p>Congressman:  It looks like Libra was built on the nightly build of the Rust programming language. It's interesting because that's not how we did releases at the DoD. What features of Rust are only available in the nightly build that aren't in the official releases of Rust? Does Facebook see it as a concern that they are dependent on unofficially released features of the Rust language?  Why the nightly releases? Do you see this as a function of the prototyping phase of this?<p>Facebook:  [No answer]