error[E0658]: use of unstable library feature 'format_args_nl': `format_args_nl` is only for internal language use and is subject to change
  --> $DIR/feature-gate-format_args_nl.rs:2:5
   |
LL |     format_args_nl!("");
   |     ^^^^^^^^^^^^^^
   |
   = help: add `#![feature(format_args_nl)]` to the crate attributes to enable

error: aborting due to previous error

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