“匹配”语句中的“使用部分移动的值”错误

Question

我的代码：

fn main() {
    let mut messages = vec![];

    let msg = Message::Write{message: "msg".to_string()};
    match msg {
        Message::Write{message} => println!("{}", message),
    };

    messages.push(msg);
}

enum Message {
    Write{message: String},
}

错误：

error: use of partially moved value: `msg` [--explain E0382]
   --> <anon>:9:19
6   |>         Message::Write{message} => println!("{}", message),
    |>                        ------- value moved here
...
9   |>     messages.push(msg);
    |>                   ^^^ value used here after move
note: move occurs because `msg.message` has type `std::string::String`, which does not implement the `Copy` trait

error: aborting due to previous error

看起来match 块中message 字段的所有权发生了变化。我只是希望能够在将枚举添加到Vec 之前输出它的值。如何编译？

Answer 1

通过引用而不是按值绑定到message 字段。

    match msg {
        Message::Write{ref message} => println!("{}", message),
    };