Type aliases
Syntax
TypeAlias :
type
IDENTIFIER Generics? WhereClause?=
Type;
A type alias defines a new name for an existing type. Type aliases are
declared with the keyword type
. Every value has a single, specific type, but
may implement several different traits, or be compatible with several different
type constraints.
For example, the following defines the type Point
as a synonym for the type
(u8, u8)
, the type of pairs of unsigned 8 bit integers:
# #![allow(unused_variables)] #fn main() { type Point = (u8, u8); let p: Point = (41, 68); #}
A type alias to an enum type cannot be used to qualify the constructors:
# #![allow(unused_variables)] #fn main() { enum E { A } type F = E; let _: F = E::A; // OK // let _: F = F::A; // Doesn't work #}