error[E0658]: `macro_rules!` attributes are unstable
  --> $DIR/feature-gate-macro-attr.rs:3:1
   |
LL | macro_rules! myattr { attr() {} => {} }
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #83527 <https://github.com/rust-lang/rust/issues/83527> for more information
   = help: add `#![feature(macro_attr)]` to the crate attributes to enable
   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date

error: aborting due to 1 previous error

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