error[E0658]: `#[doc(notable_trait)]` is experimental --> $DIR/feature-gate-doc_notable_trait.rs:1:1 | LL | #[doc(notable_trait)] | ^^^^^^^^^^^^^^^^^^^^^ | = note: see issue #45040 for more information = help: add `#![feature(doc_notable_trait)]` to the crate attributes to enable = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0658`.