Advanced Traits
Associated Types
More common than the other things, less common than the rest of the book
why this is a thing instead of a generic
The Thing Formerly Known as UFCS
Only needed when implementing super generic code
Lots of things are syntax sugar for this
Two traits that impl the same method - how to disambiguate
Coherence
Show examples of when you control traits and types or not
Ex: Cannot impl Debug on someone else's type
Solution: newtype