error[E0658]: the `#[repr(packed(n))]` attribute is experimental (see issue #33158)
  --> $DIR/feature-gate-repr_packed.rs:11:1
   |
LL | #[repr(packed(1))] //~ error: the `#[repr(packed(n))]` attribute is experimental
   | ^^^^^^^^^^^^^^^^^^
   |
   = help: add #![feature(repr_packed)] to the crate attributes to enable

error: aborting due to previous error

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