error[E0658]: the `#[rustc_safe_intrinsic]` attribute is used internally to mark intrinsics as safe
  --> $DIR/feature-gate-safe-intrinsic.rs:1:1
   |
LL | #[rustc_safe_intrinsic]
   | ^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: add `#![feature(rustc_attrs)]` to the crate attributes to enable
   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date

error: attribute should be applied to intrinsic functions
  --> $DIR/feature-gate-safe-intrinsic.rs:1:1
   |
LL | #[rustc_safe_intrinsic]
   | ^^^^^^^^^^^^^^^^^^^^^^^
...
LL | fn safe() {}
   | ------------ not an intrinsic function

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0658`.