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f67523d0b3
Tweak `.clone()` suggestion to work in more cases
When going through auto-deref, the `<T as Clone>` impl sometimes needs to be specified for rustc to actually clone the value and not the reference.
```
error[E0507]: cannot move out of dereference of `S`
--> $DIR/needs-clone-through-deref.rs:15:18
|
LL | for _ in self.clone().into_iter() {}
| ^^^^^^^^^^^^ ----------- value moved due to this method call
| |
| move occurs because value has type `Vec<usize>`, which does not implement the `Copy` trait
|
note: `into_iter` takes ownership of the receiver `self`, which moves value
--> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
help: you can `clone` the value and consume it, but this might not be your desired behavior
|
LL | for _ in <Vec<usize> as Clone>::clone(&self.clone()).into_iter() {}
| ++++++++++++++++++++++++++++++ +
```
When encountering a move error, look for implementations of `Clone` for the moved type. If there is one, check if all its obligations are met. If they are, we suggest cloning without caveats. If they aren't, we suggest cloning while mentioning the unmet obligations, potentially suggesting `#[derive(Clone)]` when appropriate.
```
error[E0507]: cannot move out of a shared reference
--> $DIR/suggest-clone-when-some-obligation-is-unmet.rs:20:28
|
LL | let mut copy: Vec<U> = map.clone().into_values().collect();
| ^^^^^^^^^^^ ------------- value moved due to this method call
| |
| move occurs because value has type `HashMap<T, U, Hash128_1>`, which does not implement the `Copy` trait
|
note: `HashMap::<K, V, S>::into_values` takes ownership of the receiver `self`, which moves value
--> $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
help: you could `clone` the value and consume it, if the `Hash128_1: Clone` trait bound could be satisfied
|
LL | let mut copy: Vec<U> = <HashMap<T, U, Hash128_1> as Clone>::clone(&map.clone()).into_values().collect();
| ++++++++++++++++++++++++++++++++++++++++++++ +
help: consider annotating `Hash128_1` with `#[derive(Clone)]`
|
LL + #[derive(Clone)]
LL | pub struct Hash128_1;
|
```
Fix #109429.
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
|
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
|
LL | let mut sm = sr.clone();
| ^^^^^^^
help: consider annotating `Str` with `#[derive(Clone)]`
|
LL + #[derive(Clone)]
LL | struct Str {
|
help: consider specifying this binding's type
|
LL | let mut sm: &mut Str = sr.clone();
| ++++++++++
```
Fix #34629. Fix #76643. Fix #91532.
|
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