| error[E0636]: the feature `box_syntax` has already been declared | |
| --> $DIR/rustc-check-passes.rs:2:12 | |
| | | |
| LL | #![feature(box_syntax)] | |
| | ^^^^^^^^^^ | |
| error: aborting due to previous error | |
| For more information about this error, try `rustc --explain E0636`. |