error: `(dyn B + 'a)` implements `Deref` with supertrait `A` as target
  --> $DIR/migrate-lint-deny.rs:11:1
   |
LL | impl<'a> Deref for dyn 'a + B {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
LL |     type Target = dyn A;
   |     -------------------- target type is set here
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #89460 <https://github.com/rust-lang/rust/issues/89460>
note: the lint level is defined here
  --> $DIR/migrate-lint-deny.rs:1:9
   |
LL | #![deny(deref_into_dyn_supertrait)]
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error