error[E0502]: cannot borrow `a` as mutable because it is also borrowed as immutable
  --> $DIR/borrowck-bad-nested-calls-free.rs:25:17
   |
LL |     add(
   |     --- immutable borrow later used by call
LL |         &*a,
   |         --- immutable borrow occurs here
LL |         rewrite(&mut a));
   |                 ^^^^^^ mutable borrow occurs here

error[E0502]: cannot borrow `a` as mutable because it is also borrowed as immutable
  --> $DIR/borrowck-bad-nested-calls-free.rs:32:17
   |
LL |     add(
   |     --- immutable borrow later used by call
LL |         &*a,
   |         --- immutable borrow occurs here
LL |         rewrite(&mut a));
   |                 ^^^^^^ mutable borrow occurs here

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0502`.