error[E0277]: expected a `std::ops::FnMut<(_, char)>` closure, found `()` | |
--> $DIR/issue-23966.rs:2:16 | |
| | |
LL | "".chars().fold(|_, _| (), ()); | |
| ^^^^ expected an `FnMut<(_, char)>` closure, found `()` | |
| | |
= help: the trait `std::ops::FnMut<(_, char)>` is not implemented for `()` | |
error: aborting due to previous error | |
For more information about this error, try `rustc --explain E0277`. |