You mean Graydon moving from Rust to Swift? On Rust he had a tremendous influence, but while he was on the team, I'm not sure about his influence on Swift. I th

You mean Graydon moving from Rust to Swift? On Rust he had a tremendous influence, but while he was on the team, I'm not sure about his influence on Swift. I think Swift is more constrained, having to have good compatibility with objective C. Rust is only compatible with C, and thus has more freedom to do away with decisions that turned out to be bad. Edit: probably Gankra too. IIRC she had an internship at mozilla designing important parts of the Rust standard library then later went to work at Apple.