Closed
Description
Given the following code (playground):
struct Testing {
a: Option<String>
}
fn testing(a: &Testing) {
let Some(_s) = a.a else {
return;
};
}The current output is:
error[[E0507]](https://doc.rust-lang.org/nightly/error-index.html#E0507): cannot move out of `a.a` as enum variant `Some` which is behind a shared reference
--> src/lib.rs:6:14
|
6 | let Some(_s) = a.a else {
| ^^
| |
| move occurs because `a.a.0` has type `String`, which does not implement the `Copy` trait
| help: consider borrowing here: `&_s`
For more information about this error, try `rustc --explain E0507`.
error: could not compile `playground` due to previous error
Ideally the output should look like:
error[[E0507]](https://doc.rust-lang.org/nightly/error-index.html#E0507): cannot move out of `a.a` as enum variant `Some` which is behind a shared reference
--> src/lib.rs:6:14
|
6 | let Some(_s) = a.a else {
| ^^ ^^^
| | |
| | help: consider borrowing here: `&a.a`
| |
| move occurs because `a.a.0` has type `String`, which does not implement the `Copy` trait
For more information about this error, try `rustc --explain E0507`.
error: could not compile `playground` due to previous error
An alternative would be to recommend using ref, but this would not be consistent with the match suggestion:
fn testing2(a: &Testing) {
match a.a {
Some(_s) => return,
None => {}
}
}error[[E0507]](https://doc.rust-lang.org/nightly/error-index.html#E0507): cannot move out of `a.a` as enum variant `Some` which is behind a shared reference
--> src/lib.rs:12:11
|
12 | match a.a {
| ^^^ help: consider borrowing here: `&a.a`
13 | Some(_s) => return,
| --
| |
| data moved here
| move occurs because `_s` has type `String`, which does not implement the `Copy` trait
Tested with Nightly version: 1.67.0-nightly (2022-11-23 70f8737)