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// Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
// Tests various fields for the `out` variance modifier.
// SharedOptions=--enable-experiment=variance
import "package:expect/expect.dart";
typedef Void2Int = int? Function();
class A<out T> {
final T? a = null;
final T? Function() b = () => null;
T? get c => null;
A<T> get d => this;
covariant late T e;
void set f(covariant T value) => value;
}
mixin BMixin<out T> {
final T? a = null;
final T? Function() b = () => null;
T? get c => null;
BMixin<T> get d => this;
covariant late T e;
void set f(covariant T value) => value;
}
class B with BMixin<int> {}
void testClass() {
A<int> a = new A();
Expect.isNull(a.a);
Expect.type<Void2Int>(a.b);
Expect.isNull(a.b());
Expect.isNull(a.c);
Expect.isNull(a.d.a);
a.e = 2;
Expect.equals(2, a.e);
a.f = 2;
}
void testMixin() {
B b = new B();
Expect.isNull(b.a);
Expect.type<Void2Int>(b.b);
Expect.isNull(b.b());
Expect.isNull(b.c);
Expect.isNull(b.d.a);
b.e = 2;
Expect.equals(2, b.e);
b.f = 2;
}
main() {
testClass();
testMixin();
}