error[E0597]: `c` does not live long enough
  --> $DIR/regionck-unboxed-closure-lifetimes.rs:19:5
   |
17 |         let c_ref = &c; //~ ERROR `c` does not live long enough
   |                      - borrow occurs here
18 |         f = move |a: isize, b: isize| { a + b + *c_ref };
19 |     }
   |     ^ `c` dropped here while still borrowed
20 | }
   | - borrowed value needs to live until here

error: aborting due to previous error