Type Alias Identity<T>

Identity — a trivial container carrying a single tagged value. Covariant in T (<out T>). isSame takes Identity<unknown> so that cross-type equality checks (semantically always false for unrelated types) don't block variance — mirroring the contains(unknown) pattern used on List/Set/Map.

type Identity<out T> = {
id: T;
isSame?: (other: Identity<unknown>) => boolean;
}