mirror of
https://github.com/rust-lang/rust
synced 2024-11-05 20:45:15 +00:00
4aba2c55e6
Start pointing to where bindings were declared when they are captured in closures:
```
error[E0597]: `x` does not live long enough
--> $DIR/suggest-return-closure.rs:23:9
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LL | let x = String::new();
| - binding `x` declared here
...
LL | |c| {
| --- value captured here
LL | x.push(c);
| ^ borrowed value does not live long enough
...
LL | }
| -- borrow later used here
| |
| `x` dropped here while still borrowed
```
Suggest cloning in more cases involving closures:
```
error[E0507]: cannot move out of `foo` in pattern guard
--> $DIR/issue-27282-move-ref-mut-into-guard.rs:11:19
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LL | if { (|| { let mut bar = foo; bar.take() })(); false } => {},
| ^^ --- move occurs because `foo` has type `&mut Option<&i32>`, which does not implement the `Copy` trait
| |
| `foo` is moved here
|
= note: variables bound in patterns cannot be moved from until after the end of the pattern guard
help: consider cloning the value if the performance cost is acceptable
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LL | if { (|| { let mut bar = foo.clone(); bar.take() })(); false } => {},
| ++++++++
```
57 lines
1.9 KiB
Text
57 lines
1.9 KiB
Text
error[E0521]: borrowed data escapes outside of closure
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--> $DIR/regions-nested-fns.rs:12:9
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LL | let mut ay = &y;
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| ------ `ay` declared here, outside of the closure body
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...
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LL | ignore::<Box<dyn for<'z> FnMut(&'z isize)>>(Box::new(|z| {
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| - `z` is a reference that is only valid in the closure body
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...
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LL | ay = z;
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| ^^^^^^ `z` escapes the closure body here
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error[E0597]: `y` does not live long enough
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--> $DIR/regions-nested-fns.rs:5:18
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LL | let y = 3;
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| - binding `y` declared here
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LL | let mut ay = &y;
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| ^^ borrowed value does not live long enough
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...
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LL | if false { return ay; }
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| -- returning this value requires that `y` is borrowed for `'static`
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...
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LL | }
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| - `y` dropped here while still borrowed
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error[E0597]: `y` does not live long enough
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--> $DIR/regions-nested-fns.rs:10:15
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LL | let y = 3;
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| - binding `y` declared here
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...
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LL | ignore::<Box<dyn for<'z> FnMut(&'z isize)>>(Box::new(|z| {
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| --- value captured here
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LL | ay = x;
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LL | ay = &y;
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| ^ borrowed value does not live long enough
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...
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LL | if false { return ay; }
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| -- returning this value requires that `y` is borrowed for `'static`
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...
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LL | }
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| - `y` dropped here while still borrowed
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error: lifetime may not live long enough
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--> $DIR/regions-nested-fns.rs:17:27
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LL | fn nested<'x>(x: &'x isize) {
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| -- lifetime `'x` defined here
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...
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LL | if false { return x; }
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| ^ returning this value requires that `'x` must outlive `'static`
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error: aborting due to 4 previous errors
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Some errors have detailed explanations: E0521, E0597.
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For more information about an error, try `rustc --explain E0521`.
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