generics

PhantomData<T> is a zero-sized type that acts as if it owns T for the purposes of lifetimes, variance, and drop check. I use it in the typestate pattern or when a struct logically depends on T but doesn't store it. For example, a handle to an ex

Associated types let a trait declare a type that implementors must define. This is cleaner than adding a generic parameter to the trait. For example, Iterator has an associated type Item rather than being Iterator<Item>. I use associated types w

Traits define shared behavior, and trait bounds let you write generic functions that work with any type implementing a trait. The syntax T: Display means "T must implement Display." This is similar to interfaces in other languages but more powerful: y