| warning: captured variable cannot escape `FnMut` closure body |
| --> $DIR/issue-40510-1.rs:11:9 |
| | |
| LL | || { |
| | - inferred to be a `FnMut` closure |
| LL | &mut x |
| | ^^^^^^ returns a reference to a captured variable which 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-40510-1.rs:20:1 |
| | |
| LL | fn main() {} |
| | ^^^^^^^^^^^^ |
| |
| error: aborting due to previous error |
| |
