error[E0658]: use of unstable library feature 'unstable_test_feature'
  --> $DIR/issue-28075.rs:9:22
   |
LL | use lint_stability::{unstable, deprecated};
   |                      ^^^^^^^^
   |
   = help: add #![feature(unstable_test_feature)] to the crate attributes to enable

error: aborting due to previous error

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