error[E0658]: the `linkage` attribute is experimental and not portable across platforms --> $DIR/feature-gate-linkage.rs:2:5 | LL | #[linkage = "extern_weak"] static foo: *mut isize; | ^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: see issue #29603 for more information = help: add `#![feature(linkage)]` to the crate attributes to enable error: aborting due to previous error For more information about this error, try `rustc --explain E0658`.