deprecated_implement

Implementing '{0}' is deprecated.

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.

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 {}

Follow any directions found in the Deprecation.implement annotation, or just remove the class name from the implements clause.

class D {}