box_syntax
The tracking issue for this feature is: #27779
See also box_patterns
Currently the only stable way to create a Box is via the Box::new method.
Also it is not possible in stable Rust to destructure a Box in a match
pattern. The unstable box keyword can be used to create a Box. An example
usage would be:
#![feature(box_syntax)] fn main() { let b = box 5; }