1 error[E0658]: attributes of the form `#[derive_*]` are reserved for the compiler (see issue #29644)
2 --> $DIR/feature-gate-custom_derive.rs:11:3
7 = help: add #![feature(custom_derive)] to the crate attributes to enable
9 error: aborting due to previous error
11 For more information about this error, try `rustc --explain E0658`.