deprecated_mixin

Mixing in '{0}' is deprecated.

The analyzer produces this diagnostic when a mixin class annotated with @Deprecated.mixin is used in the with clause of a class or enum declaration. This annotation indicates that the ability for classes to mixin the annotated mixin class is deprecated, and will soon be removed, perhaps by removing the mixin class modifier.

If the library p defines a class annotated with @Deprecated.mixin:

@Deprecated.mixin()
mixin class C {}

Then, the following code, when in a library other than p, produces this diagnostic:

import 'package:p/p.dart';
​
class D with C {}

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

class D {}