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4 commits

Author SHA1 Message Date
surechen
4821b84b92 If the moved value is a mut reference, it is used in a generic function and it's type is a generic param, it can be reborrowed to avoid moving.
for example:

```rust
struct Y(u32);
// x's type is '& mut Y' and it is used in `fn generic<T>(x: T) {}`.
fn generic<T>(x: T) {}
```

fixes #127285
2024-07-17 10:07:02 +08:00
Esteban Küber
14473adf42 Detect when move of !Copy value occurs within loop and should likely not be cloned
When encountering a move error on a value within a loop of any kind,
identify if the moved value belongs to a call expression that should not
be cloned and avoid the semantically incorrect suggestion. Also try to
suggest moving the call expression outside of the loop instead.

```
error[E0382]: use of moved value: `vec`
  --> $DIR/recreating-value-in-loop-condition.rs:6:33
   |
LL |     let vec = vec!["one", "two", "three"];
   |         --- move occurs because `vec` has type `Vec<&str>`, which does not implement the `Copy` trait
LL |     while let Some(item) = iter(vec).next() {
   |     ----------------------------^^^--------
   |     |                           |
   |     |                           value moved here, in previous iteration of loop
   |     inside of this loop
   |
note: consider changing this parameter type in function `iter` to borrow instead if owning the value isn't necessary
  --> $DIR/recreating-value-in-loop-condition.rs:1:17
   |
LL | fn iter<T>(vec: Vec<T>) -> impl Iterator<Item = T> {
   |    ----         ^^^^^^ this parameter takes ownership of the value
   |    |
   |    in this function
help: consider moving the expression out of the loop so it is only moved once
   |
LL ~     let mut value = iter(vec);
LL ~     while let Some(item) = value.next() {
   |
```

We use the presence of a `break` in the loop that would be affected by
the moved value as a heuristic for "shouldn't be cloned".

Fix #121466.
2024-03-17 21:32:26 +00:00
Nilstrieb
41e8d152dc Show number in error message even for one error
Co-authored-by: Adrian <adrian.iosdev@gmail.com>
2023-11-24 19:15:52 +01:00
Albert Larsan
cf2dff2b1e
Move /src/test to /tests 2023-01-11 09:32:08 +00:00
Renamed from src/test/ui/borrowck/mut-borrow-in-loop-2.stderr (Browse further)