1error[E0596]: cannot borrow `*buf` as mutable, as it is behind a `&` reference
2  --> $DIR/issue-40823.rs:3:5
3   |
4LL |     let mut buf = &[1, 2, 3, 4];
5   |                   ------------- help: consider changing this to be a mutable reference: `&mut [1, 2, 3, 4]`
6LL |     buf.iter_mut();
7   |     ^^^^^^^^^^^^^^ `buf` is a `&` reference, so the data it refers to cannot be borrowed as mutable
8
9error: aborting due to previous error
10
11For more information about this error, try `rustc --explain E0596`.
12