1 error[E0658]: extern types are experimental
2 --> $DIR/feature-gate-extern_types.rs:2:5
7 = note: see issue #43467 <https://github.com/rust-lang/rust/issues/43467> for more information
8 = help: add `#![feature(extern_types)]` to the crate attributes to enable
10 error: aborting due to previous error
12 For more information about this error, try `rustc --explain E0658`.