| error[E0658]: box expression syntax is experimental; you can call `Box::new` instead | |
| --> $DIR/feature-gate-box_syntax.rs:4:13 | |
| | | |
| LL | let x = box 3; | |
| | ^^^^^ | |
| | | |
| = note: for more information, see https://github.com/rust-lang/rust/issues/49733 | |
| = help: add `#![feature(box_syntax)]` to the crate attributes to enable | |
| error: aborting due to previous error | |
| For more information about this error, try `rustc --explain E0658`. |