如何实现 Rust 的 Copy 特性? [英] How can I implement Rust's Copy trait?

问题描述

我正在尝试在 Rust 中初始化一个结构数组:

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]; 

当我尝试编译时，编译器抱怨 Copy 特性没有实现:

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

如何实现 Copy 特性?

推荐答案

您不必实施 复制自己；编译器可以为您派生:

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,
}

请注意，每个实现 Copy 的类型也必须实现 克隆.Clone 也可以导出.

Note that every type that implements Copy must also implement Clone. Clone can also be derived.

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