deprecated_ implement
Implementing '{0}' is deprecated.
Description
#
The analyzer produces this diagnostic when a class annotated with
@Deprecated.implement
is used in the
implements
clause of a class or
enum declaration. This annotation indicates that the ability for classes
to implement the annotated class is deprecated, and will soon be removed,
perhaps by marking the annotated class with
interface
,
final
, or
sealed
.
Example
#If the library p
defines a class annotated with @Deprecated.implement
:
@Deprecated.implement()
class C {}
Then, the following code, when in a library other than
p
, produces this
diagnostic:
import 'package:p/p.dart';
class D implements C {}
Common fixes
#
Follow any directions found in the
Deprecation.implement
annotation, or
just remove the class name from the
implements
clause.
class D {}
Unless stated otherwise, the documentation on this site reflects Dart 3.9.2. Page last updated on 2025-9-1. View source or report an issue.