mirror of
https://github.com/rust-lang/rust
synced 2024-10-14 12:33:57 +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
|
LL | if { (|| { let mut bar = foo.clone(); bar.take() })(); false } => {},
| ++++++++
```
63 lines
2.2 KiB
Plaintext
63 lines
2.2 KiB
Plaintext
error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
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--> $DIR/suggest-return-closure.rs:1:17
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LL | fn fn_once() -> _ {
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| ^
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| not allowed in type signatures
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| help: replace with an appropriate return type: `impl FnOnce()`
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= note: for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html
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error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
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--> $DIR/suggest-return-closure.rs:13:16
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LL | fn fn_mut() -> _ {
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| ^
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| not allowed in type signatures
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| help: replace with an appropriate return type: `impl FnMut(char)`
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= note: for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html
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error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
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--> $DIR/suggest-return-closure.rs:32:13
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LL | fn fun() -> _ {
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| ^
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| not allowed in type signatures
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| help: replace with an appropriate return type: `impl Fn() -> i32`
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= note: for more information on `Fn` traits and closure types, see https://doc.rust-lang.org/book/ch13-01-closures.html
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error[E0596]: cannot borrow `x` as mutable, as it is not declared as mutable
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--> $DIR/suggest-return-closure.rs:23:9
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LL | let x = String::new();
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| - help: consider changing this to be mutable: `mut x`
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...
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LL | x.push(c);
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| ^ cannot borrow as mutable
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error[E0597]: `x` does not live long enough
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--> $DIR/suggest-return-closure.rs:23:9
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LL | let x = String::new();
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| - binding `x` declared here
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...
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LL | |c| {
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| --- value captured here
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LL | x.push(c);
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| ^ borrowed value does not live long enough
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...
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LL | }
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| -- borrow later used here
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| `x` dropped here while still borrowed
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error: aborting due to 5 previous errors
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Some errors have detailed explanations: E0121, E0596, E0597.
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For more information about an error, try `rustc --explain E0121`.
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