error[E0658]: use of unstable library feature 'alloc_error_handler' --> $DIR/feature-gate-alloc-error-handler.rs:8:3 | LL | #[alloc_error_handler] | ^^^^^^^^^^^^^^^^^^^ | = note: see issue #51540 for more information = help: add `#![feature(alloc_error_handler)]` to the crate attributes to enable error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0658`.