deprecated_ mixin
Mixing in '{0}' is deprecated.
Description
#
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 using the annotated mixin is
deprecated and will soon be removed. This change will likely be enforced
by removing the mixin class modifier.
Example
#If the library p defines a class annotated with @Deprecated.mixin:
@Deprecated.mixin()
mixin class C {}
Then, in any library other than p, the following code produces this
diagnostic:
import 'package:p/p.dart';
class D with C {}
Common fixes
#
Follow any directions found in the Deprecation.mixin annotation.
Otherwise, remove the mixin class name from the with clause.
class D {}
Unless stated otherwise, the documentation on this site reflects Dart 3.9.2. Page last updated on 2025-11-4. View source or report an issue.