error[E0658]: deriving `Default` on enums is experimental
  --> $DIR/feature-gate-derive_default_enum.rs:1:10
   |
LL | #[derive(Default)]
   |          ^^^^^^^
   |
   = note: see issue #86985 <https://github.com/rust-lang/rust/issues/86985> for more information
   = help: add `#![feature(derive_default_enum)]` to the crate attributes to enable
   = note: this error originates in the derive macro `Default` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to previous error

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