error[E0507]: cannot move out of a shared reference
  --> $DIR/borrowck-errors.rs:31:29
   |
LL |     if let Some(&Some(x)) = Some(&Some(&mut 0)) {
   |                       -     ^^^^^^^^^^^^^^^^^^^
   |                       |
   |                       data moved here
   |                       move occurs because `x` has type `&mut u32`, which does not implement the `Copy` trait
   |
help: consider removing the borrow
   |
LL -     if let Some(&Some(x)) = Some(&Some(&mut 0)) {
LL +     if let Some(Some(x)) = Some(&Some(&mut 0)) {
   |

error[E0596]: cannot borrow data in a `&` reference as mutable
  --> $DIR/borrowck-errors.rs:36:10
   |
LL |     let &ref mut x = &0;
   |          ^^^^^^^^^ cannot borrow as mutable

error[E0596]: cannot borrow data in a `&` reference as mutable
  --> $DIR/borrowck-errors.rs:41:23
   |
LL |     if let &Some(Some(x)) = &Some(&mut Some(0)) {
   |                       ^ cannot borrow as mutable

error[E0596]: cannot borrow data in a `&` reference as mutable
  --> $DIR/borrowck-errors.rs:46:11
   |
LL |     let &[x] = &&mut [0];
   |           ^ cannot borrow as mutable

error: aborting due to 4 previous errors

Some errors have detailed explanations: E0507, E0596.
For more information about an error, try `rustc --explain E0507`.