I am trying to initialise an array of structs in Rust:
enum Direction {
North,
East,
South,
West,
}
struct RoadPoint {
direction: Direction,
index: i32,
}
// Initialise the array, but failed.
let data = [RoadPoint { direction: Direction::East, index: 1 }; 4];
When I try to compile, the compiler complains that the Copy
trait is not implemented:
error[E0277]: the trait bound `main::RoadPoint: std::marker::Copy` is not satisfied
--> src/main.rs:15:16
|
15 | let data = [RoadPoint { direction: Direction::East, index: 1 }; 4];
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `main::RoadPoint`
|
= note: the `Copy` trait is required because the repeated element will be copied
How can the Copy
trait be implemented?
You don't have to implement Copy
yourself; the compiler can derive it for you:
#[derive(Copy, Clone)]
enum Direction {
North,
East,
South,
West,
}
#[derive(Copy, Clone)]
struct RoadPoint {
direction: Direction,
index: i32,
}
Note that every type that implements Copy
must also implement Clone
. Clone
can also be derived.