> Normally, Rust would complain, Not in the example given. There's nothing wrong with creating an Rc<T> loop; the borrow checker doesn't come into the picture.

> Normally, Rust would complain, Not in the example given. There's nothing wrong with creating an Rc<T> loop; the borrow checker doesn't come into the picture. > That is, you could mutate the data within an Rc as long as the data is cheap to copy. You can achieve this by wrapping your data within a Rc<Cell<T>>. T: Copy is only a bound on the .get() method. You can do this even if the data is expensive to copy, so long as you always swap in a valid representation of T. (I sometimes write Cell<Option<T>>, where it makes sense to replace with a None value.) > Embrace unsafe as long as you can prove the soundness of your API, In other words: avoid unsafe except as a last-ditch resort. > &impl Meower Should be impl Meower, if you want the same behaviour as the explicit-generic version. > Many tutorials immediately jump to iterating over vectors using the into_iter method Out of interest, what tutorials? I've never read one that does that! > Instead, there are two other useful methods on iterators Methods on many iterables in std. Not on iterators (nor iterables in general). > You can wrap the following types with PhantomData and use them in your structs as a way to tell the compiler that your struct is neither Send nor Sync. … You're doing it wrong. €30 says your unsafe code is unsound. > Embrace the monadic nature of Option and Result types Er, maybe? But try boring ol' pattern-matching first. It's usually clearer, outside examples like these ones (specially-chosen to make the helper methods shine). I'd go for if let, in this example – though if the function really just returns None in the failure case, go with the ? operator. > For example, writing a custom linked list, or writing structs that use channels, would typically need to implement a custom version of Drop. No, you don't typically need to. Rust provides an automatic implementation that probably does what you need already. Custom drop implementations are mainly useful for unsafe code. > Really annoyed by the borrow checker? Use immutable data structures No. No. Haskell has all sorts of optimisations to make "immutable everything" work, and Rust's "do what I say" nature means none of those can be applied by the compiler. If you want to program this way, pick a better language. > Instead, you can define a blanket trait that can make your code a more DRY. There are no blanket traits. There are blanket trait implementations, and you've missed that line from your example. All in all, this is a good article. There are some good tips in there, but I wouldn't recommend it to a beginner. I would recommend the author revisit it in a few months, and make some improvements: a tutorial designed when you're green, but with the experience from your older self, can be a really useful thing.