error[E0277]: the trait bound `u8: Identity` is not satisfied
  --> $DIR/projection-as-union-type-error.rs:13:9
   |
LL |     a:  <Foo as Identity>::Identity,
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Identity` is not implemented for `u8`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.