Thank you for the detailed explanation @regexident!
Interesting that I don't see similar discussions in the relatively recent Vector Manifesto topic, although it does mention a need for making generics in Swift more flexible.
I find it quite useful to look at the experience of other languages. How do you find it, does Rust manage well the presence of both traits with associated types and generic traits?
Also looking at Haskell, which arguably has the state of the art type system, I always thought that type classes directly correspond to PATs, but probably I was wrong. After another look it really seems that type classes are more like generic protocols, and actually type families are much more similar to PATs than plain type classes.