error[E0499]: cannot borrow `mu` as mutable more than once at a time
--> tests/ui/double_borrow.rs:16:43
|
12 | munge!(let Example { a: a1, b: b1 } = &mut mu);
| ------- first mutable borrow occurs here
...
16 | munge!(let Example { a: a2, b: b2 } = &mut mu);
| ^^^^^^^ second mutable borrow occurs here
17 | assert_eq!(a1.write(3), &3);
| -- first borrow later used here