Rust has a borrow checker. I think it is unique/novel, and I definitely don't think it is simple. In fact, it's precisely because I think it is unique/novel tha

Rust has a borrow checker. I think it is unique/novel, and I definitely don't think it is simple. In fact, it's precisely because I think it is unique/novel that I very much am not surprised that it doesn't exist in other languages that I use. Why on earth would I be surprised that a feature I think was just invented isn't yet present in other things? That's not how the passage of time works. On the other hand, Rust also has first-class functions including closures. I do think that closures are a simple programming language feature, and I'm definitely surprised/put off when I write a language that doesn't have them (though these days I'm not sure there are any mainstream ones, now that Java and C++ both have them in the spec). Again it's precisely because I think of closures as the opposite of unique/novel that I am surprised at their absence. Why would I be surprised that a language does not have closures if I thought the Rust team just made them up? So yes, I have no idea how one would conclude that someone's surprise at a simple feature being unavailable indicates that they think the feature is unique or novel, other than just being a knee-jerk reaction.