error[E0658]: the `#[unwind]` attribute is an experimental feature
  --> $DIR/feature-gate-unwind-attributes.rs:12:5
   |
LL |     #[unwind(allowed)]
   |     ^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, see https://github.com/rust-lang/rust/issues/58760
   = help: add `#![feature(unwind_attributes)]` to the crate attributes to enable

error: aborting due to previous error

For more information about this error, try `rustc --explain E0658`.