error[E0658]: attributes starting with `rustc` are reserved for use by the `rustc` compiler
  --> $DIR/reserved-attr-on-macro.rs:1:3
   |
LL | #[rustc_attribute_should_be_reserved]
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, see https://github.com/rust-lang/rust/issues/29642
   = help: add `#![feature(rustc_attrs)]` to the crate attributes to enable

error: cannot determine resolution for the macro `foo`
  --> $DIR/reserved-attr-on-macro.rs:10:5
   |
LL |     foo!();
   |     ^^^
   |
   = note: import resolution is stuck, try simplifying macro imports

error: cannot find attribute `rustc_attribute_should_be_reserved` in this scope
  --> $DIR/reserved-attr-on-macro.rs:1:3
   |
LL | #[rustc_attribute_should_be_reserved]
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 3 previous errors

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