Deprecated constructor

const Deprecated(String expires)

Create a deprecation annotation which specifies the expiration of the annotated feature.

The expires argument should be readable by programmers, and should state when an annotated feature is expected to be removed. This can be specified, for example, as a date, as a release number, or as relative to some other change (like "when bug 4418 is fixed").

Implementation 

const Deprecated(String expires) : this.expires = expires;