error: unknown feature `unknown_rust_feature`
  --> $DIR/unknown-feature.rs:13:12
   |
LL | #![feature(unknown_rust_feature)] //~ ERROR unknown feature
   |            ^^^^^^^^^^^^^^^^^^^^
   |
note: lint level defined here
  --> $DIR/unknown-feature.rs:11:9
   |
LL | #![deny(unknown_features)]
   |         ^^^^^^^^^^^^^^^^

error: aborting due to previous error