error[E0597]: `db` does not live long enough
 --> tests/fail/checkpoint_outlive_db.rs:7:25
  |
5 |     let _checkpoint = {
  |         ----------- borrow later stored here
6 |         let db = DB::open_default("foo").unwrap();
  |             -- binding `db` declared here
7 |         Checkpoint::new(&db)
  |                         ^^^ borrowed value does not live long enough
8 |     };
  |     - `db` dropped here while still borrowed