error[E0658]: use of unstable library feature 'unstable_test_feature'
  --> $DIR/lint-output-format.rs:16:1
   |
LL | extern crate lint_output_format; //~ ERROR use of unstable library feature
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: add #![feature(unstable_test_feature)] to the crate attributes to enable

error[E0658]: use of unstable library feature 'unstable_test_feature'
  --> $DIR/lint-output-format.rs:17:31
   |
LL | use lint_output_format::{foo, bar}; //~ ERROR use of unstable library feature
   |                               ^^^
   |
   = help: add #![feature(unstable_test_feature)] to the crate attributes to enable

error[E0658]: use of unstable library feature 'unstable_test_feature'
  --> $DIR/lint-output-format.rs:21:14
   |
LL |     let _y = bar(); //~ ERROR use of unstable library feature
   |              ^^^
   |
   = help: add #![feature(unstable_test_feature)] to the crate attributes to enable

error: aborting due to 3 previous errors

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