CODEWITHSUNDEEP
rust
Michael
Michael

Reputation: 35341

"use of partially moved value" error in "match" statement

My code:

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},
}

The error:

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

It looks like the ownership of the message field changes in the match block. I just want to be able to output the value of the enum before adding it to the Vec. How do I make this compile?

Upvotes: 6

Views: 7954

Answers (1)

DK.
DK.

Reputation: 59005

Bind to the message field by-reference instead of by-value.

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

Upvotes: 17

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