tests/ui/feature-gates/feature-gate-decl_macro.stderr

   1 error[E0658]: `macro` is experimental
   2   --> $DIR/feature-gate-decl_macro.rs:3:1
   3    |
   4 LL | macro m() {}
   5    | ^^^^^^^^^^^^
   6    |
   7    = note: see issue #39412 <https://github.com/rust-lang/rust/issues/39412> for more information
   8    = help: add `#![feature(decl_macro)]` to the crate attributes to enable
   9
  10 error: aborting due to previous error
  11
  12 For more information about this error, try `rustc --explain E0658`.