error[E0658]: use of unstable library feature 'unstable_test_feature'
  --> $DIR/lint-output-format.rs:6:1
   |
LL | extern crate lint_output_format;
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: add `#![feature(unstable_test_feature)]` 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   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date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[E0658]: use of unstable library feature 'unstable_test_feature'
  --> $DIR/lint-output-format.rs:7:26
   |
LL | use lint_output_format::{foo, bar};
   |                          ^^^
   |
   = help: add `#![feature(unstable_test_feature)]` 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   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date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[E0658]: use of unstable library feature 'unstable_test_feature'
  --> $DIR/lint-output-format.rs:7:31
   |
LL | use lint_output_format::{foo, bar};
   |                               ^^^
   |
   = help: add `#![feature(unstable_test_feature)]` 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   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date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[E0658]: use of unstable library feature 'unstable_test_feature'
  --> $DIR/lint-output-format.rs:12:14
   |
LL |     let _y = bar();
   |              ^^^
   |
   = help: add `#![feature(unstable_test_feature)]` 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   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date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 4 previous errors

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