--- /dev/null
+error[E0277]: the trait bound `u8: NotImplemented` is not satisfied
+ --> $DIR/projection-as-union-type-error-2.rs:18:8
+ |
+LL | a: <Foo as Identity>::Identity,
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `NotImplemented` is not implemented for `u8`
+ |
+note: required for `u8` to implement `Identity`
+ --> $DIR/projection-as-union-type-error-2.rs:11:25
+ |
+LL | impl<T: NotImplemented> Identity for T {
+ | -------------- ^^^^^^^^ ^
+ | |
+ | unsatisfied trait bound introduced here
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.