1 error[E0658]: the `#[no_core]` attribute is an experimental feature
2 --> $DIR/feature-gate-no_core.rs:3:1
7 = note: see issue #29639 <https://github.com/rust-lang/rust/issues/29639> for more information
8 = help: add `#![feature(no_core)]` to the crate attributes to enable
10 error: aborting due to previous error
12 For more information about this error, try `rustc --explain E0658`.