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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
#}

© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/reference/items/type-aliases.html