error[E0605]: non-primitive cast: `Self` as `&dyn std::ops::Index<usize, Output = <Self as std::ops::Index<usize>>::Output>`
  --> $DIR/issue-22312.rs:11:24
   |
LL |         let indexer = &(*self as &dyn Index<usize, Output = <Self as Index<usize>>::Output>);
   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait

error: aborting due to previous error

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