error[E0605]: non-primitive cast: `Kind2` as `u8`
  --> $DIR/issue-88621.rs:9:13
   |
LL |     let _ = Kind2::Foo() as u8;
   |             ^^^^^^^^^^^^^^^^^^ an `as` expression can be used to convert enum types to numeric types only if the enum type is unit-only or field-less
   |
   = note: see https://doc.rust-lang.org/reference/items/enumerations.html#casting for more information

error: aborting due to 1 previous error

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