Add test for issue 28821

pkg/analyzer/test/generated/strong_mode_test.dart

Index: pkg/analyzer/test/generated/strong_mode_test.dart
diff --git a/pkg/analyzer/test/generated/strong_mode_test.dart b/pkg/analyzer/test/generated/strong_mode_test.dart
index 68b717018d223200af59fdc7ea710555418b2db1..ac834e6460a3b44a0ae208e41725c85702cc73cb 100644
--- a/pkg/analyzer/test/generated/strong_mode_test.dart
+++ b/pkg/analyzer/test/generated/strong_mode_test.dart
@@ -1172,22 +1172,22 @@ class StrongModeLocalInferenceTest extends ResolverTestCase {
     _isFutureOf([_isObject])(invoke.staticType);
   }
 
-  test_futureOrNull_no_return_value() async {
+  test_futureOrNull_no_return() async {
     MethodInvocation invoke = await _testFutureOr(r'''
     FutureOr<T> mk<T>(Future<T> x) => x;
     Future<int> f;
-    test() => f.then<Null>((int x) {return;});
+    test() => f.then<Null>((int x) {});
     ''');
     _isFunction2Of(_isInt, _isNull)(
         invoke.argumentList.arguments[0].staticType);
     _isFutureOfNull(invoke.staticType);
   }
 
-  test_futureOrNull_no_return() async {
+  test_futureOrNull_no_return_value() async {
     MethodInvocation invoke = await _testFutureOr(r'''
     FutureOr<T> mk<T>(Future<T> x) => x;
     Future<int> f;
-    test() => f.then<Null>((int x) {});
+    test() => f.then<Null>((int x) {return;});
     ''');
     _isFunction2Of(_isInt, _isNull)(
         invoke.argumentList.arguments[0].staticType);
@@ -2661,6 +2661,22 @@ class D extends C {
 ''');
   }
 
+  test_genericMethod_override_covariant_field() async {
+    Source source = addSource(r'''
+abstract class A {
+  num get x;
+  set x(covariant num);
+}
+
+class B extends A {
+  int x;
+}
+''');
+    await computeAnalysisResult(source);
+    assertNoErrors(source);
+    verify([source]);
+  }
+
   test_genericMethod_override_invalidReturnType() async {
     Source source = addSource(r'''
 class C {