> But it is verbose. I think this is part of the problem with Rust learnability, because Rust makes inefficient code evident (think unsafe, clone and Rc), and that makes experienced programmers want to remove the inefficiency before they are proficient with the language enough to do so, so they encounter the hardest edges of the language early.

That's a really, really insightful way to frame it. I don't think I agree that it's a problem, though. Indeed, it's probably the very thing I like most. There's a fine line between syntactic sugar and obfuscating the underlying principles (e.g., I think async syntax is toeing that line). I feel (and I've read others saying the same) that one of the reasons Rust has made me a better programmer is because it makes thinking about this complexity second-nature, and now I do it even when other languages permit (or encourage!) me to forget it.

I'm big on pedagogical rigor and I think there's a particular way to come at learning Rust that results in things like Arc/Rc/RefCell et al feeling good and natural (also, dealing with Result::Err, for similar reasons). I think both of our experiences are equally valid and probably entirely situational. I'll have to think a bit more about it. I have an opportunity to teach Rust to a large-ish group within my company, so it's top of mind for me right now.