Deprecated.implement constructor

Creates an annotation which deprecates implementing a class or mixin.

The annotation can be used on class or mixin declarations whose interface can currently be implemented, so they are not marked final, sealed, or base, but where the ability to implement will be removed in a later release.

Any existing class, mixin or enum declaration which implements the interface will cause a warning that such use is deprecated. Does not affect classes which extend or mix in the annotated class or mixin (see Deprecated.extend, Deprecated.mixin, and Deprecated.subclass).

The annotation is not inherited by subclasses. If a public subclass will also become unimplementable, which it will if the annotated declaration becomes final or base, but not if it becomes sealed, then the subclass should deprecate implementation as well.

The message, if given, is displayed as part of the warning. The message should be aimed at the programmer who owns the implementing class, and should recommend an alternative (if available), and say when this functionality is expected to be removed if that is sooner or later than the next major version.