[−][src]Keyword type
Define an alias for an existing type.
The syntax is type Name = ExistingType;
.
Examples
type
does not create a new type:
type Meters = u32; type Kilograms = u32; let m: Meters = 3; let k: Kilograms = 3; assert_eq!(m, k);Run
In traits, type
is used to declare an associated type:
trait Iterator { // associated type declaration type Item; fn next(&mut self) -> Option<Self::Item>; } struct Once<T>(Option<T>); impl<T> Iterator for Once<T> { // associated type definition type Item = T; fn next(&mut self) -> Option<Self::Item> { self.0.take() } }Run