Fun thing, is Rust employs the same trick. The HashSet<T> is an alias for HashMap<T, ()>. "()" is the unit type. Which is zero-sized. Because Rust has generics

Fun thing, is Rust employs the same trick. The HashSet<T> is an alias for HashMap<T, ()>. "()" is the unit type. Which is zero-sized. Because Rust has generics, it is more ergonomic though. https://doc.rust-lang.org/std/collections/struct.HashSet.html https://doc.rust-lang.org/std/collections/struct.HashSet.htm...