| error[E0658]: this is an internal attribute that will never be stable |
| --> $DIR/feature-gate-on-unimplemented.rs:3:1 |
| | |
| LL | #[rustc_on_unimplemented = "test error `{Self}` with `{Bar}`"] |
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| | |
| = 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| = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date |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: aborting due to 1 previous error |
| |
| For more information about this error, try `rustc --explain E0658`. |
