private_collision_in_mixin_application

The private name '{0}', defined by '{1}', conflicts with the same name defined by '{2}'.

The analyzer produces this diagnostic when two mixins that define the same private member are used together in a single class in a library other than the one that defines the mixins.

Given a file a.dart containing the following code:

mixin A {
  void _foo() {}
}
​
mixin B {
  void _foo() {}
}

The following code produces this diagnostic because the mixins A and B both define the method _foo:

import 'a.dart';
​
class C extends Object with A, B {}

If you don't need both of the mixins, then remove one of them from the with clause:

import 'a.dart';
​
class C extends Object with A, B {}

If you need both of the mixins, then rename the conflicting member in one of the two mixins.