| error[E0658]: `#[diagnostic]` attribute name space is experimental |
| --> $DIR/feature-gate-diagnostic_on_unimplemented.rs:1:3 |
| | |
| LL | #[diagnostic::on_unimplemented(message = "Foo")] |
| | ^^^^^^^^^^ |
| | |
| = note: see issue #111996 <https://github.com/rust-lang/rust/issues/111996> for more information |
| = help: add `#![feature(diagnostic_namespace)]` 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| = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date |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`. |