1 error[E0596]: cannot borrow `*z.0.0` as mutable, as it is behind a `&` reference
2 --> $DIR/cant-mutate-imm-borrow.rs:13:17
5 | ^^ cannot borrow as mutable
7 LL | z.0.0.0 = format!("X1");
8 | ------- mutable borrow occurs due to use of `*z.0.0` in closure
10 error: aborting due to previous error
12 For more information about this error, try `rustc --explain E0596`.