Commit Graph

10 Commits

Author SHA1 Message Date
Michael Goulet
91acacf85b Peel off explicit (or implicit) deref before suggesting clone on move error in borrowck 2024-07-26 14:41:56 -04:00
Esteban Küber
d68f2a6b71 Mention when type parameter could be Clone
```
error[E0382]: use of moved value: `t`
  --> $DIR/use_of_moved_value_copy_suggestions.rs:7:9
   |
LL | fn duplicate_t<T>(t: T) -> (T, T) {
   |                   - move occurs because `t` has type `T`, which does not implement the `Copy` trait
...
LL |     (t, t)
   |      -  ^ value used here after move
   |      |
   |      value moved here
   |
help: if `T` implemented `Clone`, you could clone the value
  --> $DIR/use_of_moved_value_copy_suggestions.rs:4:16
   |
LL | fn duplicate_t<T>(t: T) -> (T, T) {
   |                ^ consider constraining this type parameter with `Clone`
...
LL |     (t, t)
   |      - you could clone this value
help: consider restricting type parameter `T`
   |
LL | fn duplicate_t<T: Copy>(t: T) -> (T, T) {
   |                 ++++++
```

The `help` is new. On ADTs, we also extend the output with span labels:

```
error[E0507]: cannot move out of static item `FOO`
  --> $DIR/issue-17718-static-move.rs:6:14
   |
LL |     let _a = FOO;
   |              ^^^ move occurs because `FOO` has type `Foo`, which does not implement the `Copy` trait
   |
note: if `Foo` implemented `Clone`, you could clone the value
  --> $DIR/issue-17718-static-move.rs:1:1
   |
LL | struct Foo;
   | ^^^^^^^^^^ consider implementing `Clone` for this type
...
LL |     let _a = FOO;
   |              --- you could clone this value
help: consider borrowing here
   |
LL |     let _a = &FOO;
   |              +
```
2024-04-24 22:21:15 +00:00
Esteban Küber
d97d2fe744 Mention when the type of the moved value doesn't implement Clone 2024-04-11 16:41:42 +00:00
Michael Goulet
04a6fd241b Make InferCtxtExt::could_impl_trait less messed up 2024-01-13 22:00:34 +00:00
Esteban Küber
90db536741 Tweak output on specific case 2023-12-04 21:54:32 +00:00
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
Michael Goulet
3a3f4a2144 Don't use method span on clone suggestion 2023-07-10 20:09:28 +00:00
Michael Goulet
fe870424a7 Do not set up wrong span for adjustments 2023-07-10 20:09:26 +00:00
Esteban Küber
7b8251e188 Account for method call and indexing when looking for inner-most path in expression 2023-01-17 02:52:43 +00:00
Albert Larsan
cf2dff2b1e Move /src/test to /tests 2023-01-11 09:32:08 +00:00