error[E0308]: mismatched types
  --> $DIR/cross-borrow-trait.rs:20:22
   |
LL |     let _y: &Trait = x; //~ ERROR E0308
   |                      ^
   |                      |
   |                      expected &dyn Trait, found struct `std::boxed::Box`
   |                      help: consider borrowing here: `&x`
   |
   = note: expected type `&dyn Trait`
              found type `std::boxed::Box<dyn Trait>`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.