unsized_coercion3.old.stderr

error: cannot check whether the hidden type of opaque type satisfies auto traits
  --> $DIR/unsized_coercion3.rs:15:32
   |
LL |         let y: Box<dyn Send> = x;
   |                                ^
   |
   = note: fetching the hidden types of an opaque inside of the defining scope is not supported. You can try moving the opaque type and the item that actually registers a hidden type into a new submodule
note: opaque type is declared here
  --> $DIR/unsized_coercion3.rs:11:19
   |
LL | fn hello() -> Box<impl Trait + ?Sized> {
   |                   ^^^^^^^^^^^^^^^^^^^
   = note: required for the cast from `Box<impl Trait + ?Sized>` to `Box<dyn Send>`

error[E0277]: the size for values of type `impl Trait + ?Sized` cannot be known at compilation time
  --> $DIR/unsized_coercion3.rs:15:32
   |
LL |         let y: Box<dyn Send> = x;
   |                                ^ doesn't have a size known at compile-time
   |
   = help: the trait `Sized` is not implemented for `impl Trait + ?Sized`
   = note: required for the cast from `Box<impl Trait + ?Sized>` to `Box<dyn Send>`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0277`.