LL | #[rustc_variance]
| ^^^^^^^^^^^^^^^^^
|
- = note: see issue #29642 <https://github.com/rust-lang/rust/issues/29642> for more information
= help: add `#![feature(rustc_attrs)]` to the crate attributes to enable
error[E0658]: the `#[rustc_error]` attribute is just used for rustc unit tests and will never be stable
LL | #[rustc_error]
| ^^^^^^^^^^^^^^
|
- = note: see issue #29642 <https://github.com/rust-lang/rust/issues/29642> for more information
= help: add `#![feature(rustc_attrs)]` to the crate attributes to enable
error[E0658]: the `#[rustc_nonnull_optimization_guaranteed]` attribute is just used to enable niche optimizations in libcore and will never be stable
LL | #[rustc_nonnull_optimization_guaranteed]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
- = note: see issue #29642 <https://github.com/rust-lang/rust/issues/29642> for more information
= help: add `#![feature(rustc_attrs)]` to the crate attributes to enable
error: aborting due to 3 previous errors