error[E0605]: non-primitive cast: `Self` as `&dyn Index<usize, Output = <Self as Index<usize>>::Output>`
  --> $DIR/issue-22312.rs:11:24
   |
LL |         let indexer = &(*self as &dyn Index<usize, Output = <Self as Index<usize>>::Output>);
   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid cast
   |
help: consider borrowing the value
   |
LL |         let indexer = &(&*self as &dyn Index<usize, Output = <Self as Index<usize>>::Output>);
   |                         +

error: aborting due to 1 previous error

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