I don't think the comments mean to say the list is useless. It's a nice overview and I learned a few things as well. However, having written non-trivial amount

I don't think the comments mean to say the list is useless. It's a nice overview and I learned a few things as well. However, having written non-trivial amount of code in Rust, it really struck me at how many places there are various factual errors (however small they are). And yes, Rust is a complex lang, but if you mix terms like this without noticing the differences, I'm afraid that will make it easier. To add an example of my own: fn do_the_meow(meower: Meower) seems like you want to take (consume, own) an object implementing Meower, which is correctly explained not possible like this. A suggested solution, fn do_the_meow(meower: &dyn Meower) is very different - it is now correct with regards to a trait access, however, now you're just taking a reference. Correct replacement would be Box<dyn Meower>. And the final solutions, fn do_the_meow<M: Meower>(meower: M) fn do_the_meow(meower: &impl Meower) the first one is correct and equivalent to the original intent - it takes (owns) the value. However, the second variant (which is, again, as correctly stated, the best solution), is different again - it takes a reference (`&`) to `impl Meower`. Coming back to my point - it is important to separate the difference between the ampersand and the impl/dyn part. To suggest an improvement, one could first write all variants of this function taking a reference (`&Meower`, `&dyn Meower`, `&M` and `&impl Meower`), and later introduce the difference between where one can use sized/unsized types, and that Box<dyn Meower> is owned equivalent of &dyn Meower, and why one can't have owned `dyn Meower` just lying around.