| error[E0525]: expected a closure that implements the `Fn` trait, but this closure only implements `FnMut` |
| --> $DIR/issue-34349.rs:26:17 |
| | |
| LL | let diary = || { //~ ERROR E0525 |
| | ^^ this closure implements `FnMut`, not `Fn` |
| LL | farewell.push_str("!!!"); |
| | -------- closure is `FnMut` because it mutates the variable `farewell` here |
| ... |
| LL | apply(diary); |
| | ----- the requirement to implement `Fn` derives from here |
| |
| error: aborting due to previous error |
| |
| For more information about this error, try `rustc --explain E0525`. |
