error[E0658]: attributes starting with `rustc` are reserved for use by the `rustc` compiler | |
--> $DIR/expand-to-unstable-2.rs:10:10 | |
| | |
LL | #[derive(Unstable)] | |
| ^^^^^^^^ | |
| | |
= help: add `#![feature(rustc_attrs)]` to the crate attributes to enable | |
= note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info) | |
error: aborting due to previous error | |
For more information about this error, try `rustc --explain E0658`. |