error: trait objects without an explicit `dyn` are deprecated
  --> $DIR/issue-61963.rs:20:14
   |
LL |     bar: Box<Bar>,
   |              ^^^ help: use `dyn`: `dyn Bar`
   |
note: lint level defined here
  --> $DIR/issue-61963.rs:3:9
   |
LL | #![deny(bare_trait_objects)]
   |         ^^^^^^^^^^^^^^^^^^

error: aborting due to previous error