| warning: captured variable cannot escape `FnMut` closure body |
| --> $DIR/issue-49824.rs:10:9 |
| | |
| LL | || { |
| | - inferred to be a `FnMut` closure |
| LL | / || { |
| LL | | |
| LL | | |
| LL | | |
| LL | | let _y = &mut x; |
| LL | | } |
| | |_________^ returns a closure that contains a reference to a captured variable, which then escapes the closure body |
| | |
| = note: `FnMut` closures only have access to their captured variables while they are executing... |
| = note: ...therefore, they cannot allow references to captured variables to escape |
| = warning: this error has been downgraded to a warning for backwards compatibility with previous releases |
| = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future |
| = note: for more information, try `rustc --explain E0729` |
| |
| error: compilation successful |
| --> $DIR/issue-49824.rs:6:1 |
| | |
| LL | / fn main() { |
| LL | | |
| LL | | let mut x = 0; |
| LL | | || { |
| ... | |
| LL | | }; |
| LL | | } |
| | |_^ |
| |
| error: aborting due to previous error |
| |
