rust/tests/ui/borrowck/suggest-as-ref-on-mut-closure.stderr
Esteban Küber 98cfed7b97 Suggest cloning and point out obligation errors on move error
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.
2023-12-04 21:54:32 +00:00

29 lines
1.3 KiB
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error[E0507]: cannot move out of `*cb` which is behind a mutable reference
--> $DIR/suggest-as-ref-on-mut-closure.rs:7:5
|
LL | cb.map(|cb| cb());
| ^^ -------------- `*cb` moved due to this method call
| |
| help: consider calling `.as_ref()` or `.as_mut()` to borrow the type's contents
| move occurs because `*cb` has type `Option<&mut dyn FnMut()>`, which does not implement the `Copy` trait
|
note: `Option::<T>::map` takes ownership of the receiver `self`, which moves `*cb`
--> $SRC_DIR/core/src/option.rs:LL:COL
help: you could `clone` the value and consume it, if the `&mut dyn FnMut(): Clone` trait bound could be satisfied
|
LL | <Option<&mut dyn FnMut()> as Clone>::clone(&cb).map(|cb| cb());
| ++++++++++++++++++++++++++++++++++++++++++++ +
error[E0596]: cannot borrow `*cb` as mutable, as it is behind a `&` reference
--> $DIR/suggest-as-ref-on-mut-closure.rs:12:26
|
LL | cb.as_ref().map(|cb| cb());
| -- ^^ `cb` is a `&` reference, so the data it refers to cannot be borrowed as mutable
| |
| consider changing this binding's type to be: `&mut &mut dyn FnMut()`
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0507, E0596.
For more information about an error, try `rustc --explain E0507`.