error[E0605]: non-primitive cast: `(dyn* Tr + 'static)` as `usize`
  --> $DIR/dyn-to-rigid.rs:7:5
   |
LL |     x as usize
   |     ^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0605`.