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