error[E0804]: cannot add auto trait `Send` to dyn bound via pointer cast
  --> $DIR/ptr-to-trait-obj-add-auto.rs:4:5
   |
LL |     x as _
   |     ^^^^^^ unsupported cast
   |
   = note: this could allow UB elsewhere
   = help: use `transmute` if you're sure this is sound

error[E0804]: cannot add auto traits `Send`, `Sync`, and `Unpin` to dyn bound via pointer cast
  --> $DIR/ptr-to-trait-obj-add-auto.rs:13:5
   |
LL |     x as _
   |     ^^^^^^ unsupported cast
   |
   = note: this could allow UB elsewhere
   = help: use `transmute` if you're sure this is sound

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0804`.