error[E0658]: unadjusted ABI is an implementation detail and perma-unstable --> $DIR/feature-gate-abi_unadjusted.rs:1:8 | LL | extern "unadjusted" fn foo() { | ^^^^^^^^^^^^ | = help: add `#![feature(abi_unadjusted)]` to the crate attributes to enable error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0658`.