Rollup merge of #83945 - SkiFire13:fix-83924, r=estebank

Add suggestion to reborrow mutable references when they're moved in a for loop

Address #83924
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Dylan DPC 2021-04-07 13:07:17 +02:00 committed by GitHub
commit d7d42ccfd2
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4 changed files with 83 additions and 1 deletions

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// run-rustfix
fn main() {
let mut values = vec![10, 11, 12];
let v = &mut values;
let mut max = 0;
for n in &mut *v {
max = std::cmp::max(max, *n);
}
println!("max is {}", max);
println!("Converting to percentages of maximum value...");
for n in v {
//~^ ERROR: use of moved value: `v` [E0382]
*n = 100 * (*n) / max;
}
println!("values: {:#?}", values);
}

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// run-rustfix
fn main() {
let mut values = vec![10, 11, 12];
let v = &mut values;
let mut max = 0;
for n in v {
max = std::cmp::max(max, *n);
}
println!("max is {}", max);
println!("Converting to percentages of maximum value...");
for n in v {
//~^ ERROR: use of moved value: `v` [E0382]
*n = 100 * (*n) / max;
}
println!("values: {:#?}", values);
}

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error[E0382]: use of moved value: `v`
--> $DIR/issue-83924.rs:15:14
|
LL | let v = &mut values;
| - move occurs because `v` has type `&mut Vec<i32>`, which does not implement the `Copy` trait
...
LL | for n in v {
| - `v` moved due to this implicit call to `.into_iter()`
...
LL | for n in v {
| ^ value used here after move
|
note: this function takes ownership of the receiver `self`, which moves `v`
--> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
|
LL | fn into_iter(self) -> Self::IntoIter;
| ^^^^
help: consider creating a fresh reborrow of `v` here
|
LL | for n in &mut *v {
| ^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0382`.