error[E0658]: `rustc_doc_primitive` is a rustc internal attribute --> $DIR/feature-gate-doc_primitive.rs:1:1 | LL | #[rustc_doc_primitive = "usize"] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(rustc_attrs)]` to the crate attributes to enable error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0658`.