error[E0658]: use of unstable library feature 'custom_test_frameworks': custom test frameworks are an unstable feature --> $DIR/feature-gate-custom_test_frameworks.rs:3:3 | LL | #[test_case] | ^^^^^^^^^ | = note: see issue #50297 for more information = help: add `#![feature(custom_test_frameworks)]` to the crate attributes to enable = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error[E0658]: custom test frameworks are an unstable feature --> $DIR/feature-gate-custom_test_frameworks.rs:1:1 | LL | #![test_runner(main)] | ^^^^^^^^^^^^^^^^^^^^^ | = note: see issue #50297 for more information = help: add `#![feature(custom_test_frameworks)]` to the crate attributes to enable = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0658`.