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When encountering multiple mutable borrows, suggest cloning and adding
derive annotations as needed.
```
error[E0596]: cannot borrow `sm.x` as mutable, as it is behind a `&` reference
--> $DIR/accidentally-cloning-ref-borrow-error.rs:32:9
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LL | foo(&mut sm.x);
| ^^^^^^^^^ `sm` is a `&` reference, so the data it refers to cannot be borrowed as mutable
|
help: `Str` doesn't implement `Clone`, so this call clones the reference `&Str`
--> $DIR/accidentally-cloning-ref-borrow-error.rs:31:21
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LL | let mut sm = sr.clone();
| ^^^^^^^
help: consider annotating `Str` with `#[derive(Clone)]`
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LL + #[derive(Clone)]
LL | struct Str {
|
help: consider specifying this binding's type
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LL | let mut sm: &mut Str = sr.clone();
| ++++++++++
```
```
error[E0596]: cannot borrow `*inner` as mutable, as it is behind a `&` reference
--> $DIR/issue-91206.rs:14:5
|
LL | inner.clear();
| ^^^^^ `inner` is a `&` reference, so the data it refers to cannot be borrowed as mutable
|
help: you can `clone` the `Vec<usize>` value and consume it, but this might not be your desired behavior
--> $DIR/issue-91206.rs:11:17
|
LL | let inner = client.get_inner_ref();
| ^^^^^^^^^^^^^^^^^^^^^^
help: consider specifying this binding's type
|
LL | let inner: &mut Vec<usize> = client.get_inner_ref();
| +++++++++++++++++
```
18 lines
564 B
Rust
18 lines
564 B
Rust
struct TestClient;
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impl TestClient {
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fn get_inner_ref(&self) -> &Vec<usize> {
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todo!()
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}
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}
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fn main() {
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let client = TestClient;
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let inner = client.get_inner_ref();
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//~^ HELP consider specifying this binding's type
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//~| HELP you can `clone` the `Vec<usize>` value and consume it, but this might not be your desired behavior
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inner.clear();
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//~^ ERROR cannot borrow `*inner` as mutable, as it is behind a `&` reference [E0596]
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//~| NOTE `inner` is a `&` reference, so the data it refers to cannot be borrowed as mutable
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}
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