type

Declares a type alias, or an associated type in a trait or impl.

type Name = T; gives an existing type a new name; the alias is replaced by its type at compile time and may take type parameters. Inside a trait, type Elem; declares an associated type that each impl defines with type Elem = int;.

type UserId = int;
type Pair<T> = (T, T);

fn swap(Pair<UserId> p) -> Pair<UserId> {
    return (p[1], p[0]);
}

See also#

• fn: Declares a function, a method, or (written in an expression) an anonymous function.
• let: Declares a mutable local variable.
• const: Declares a binding that cannot be reassigned: a local, a module constant, or a class field that is set only by new.
• static: Declares a module-level or class-level slot shared by the whole program, or a method without self.
• readonly: A read-only view of a value: nothing reachable through it can be changed.
• if: Runs a block when a bool condition is true.
• else: Introduces the branch of an if that runs when its condition is false (or its pattern does not match).
• while: Repeats a block while a bool condition is true.