Use "Object" as the reified type of covariant override parameters.

tests/language_strong/covariant_override/tear_off_type_test.dart

Index: tests/language_strong/covariant_override/tear_off_type_test.dart
diff --git a/tests/language_strong/covariant_override/tear_off_type_test.dart b/tests/language_strong/covariant_override/tear_off_type_test.dart
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+++ b/tests/language_strong/covariant_override/tear_off_type_test.dart
@@ -0,0 +1,156 @@
+// Copyright (c) 2016, 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.
+
+import "package:expect/expect.dart";
+import 'package:meta/meta.dart' show checked;
+
+// If a parameter is directly or indirectly a covariant override, its type in
+// the method tear-off should become Object.
+
+typedef void TakeInts(int a, int b, int c, int d, int e);
+typedef void TakeObjectsAndInts(Object a, int b, Object c, int d, int e);
+typedef void TakeObjects(Object a, Object b, Object c, Object d, Object e);
+
+typedef void TakeOptionalInts([int a, int b, int c, int d]);
+typedef void TakeOptionalObjectsAndInts([Object a, int b, Object c, int d]);
+
+typedef void TakeNamedInts({int a, int b, int c, int d});
+typedef void TakeNamedObjectsAndInts({Object a, int b, Object c, int d});
+
+class M1 {
+  method(@checked int a, int b) {}
+}
+
+class M2 {
+  method(int a, @checked int b) {}
+}
+
+class C extends Object with M1, M2 {}
+
+class Direct {
+  void positional(@checked int a, int b, @checked int c, int d, int e) {}
+  void optional([@checked int a, int b, @checked int c, int d]) {}
+  void named({@checked int a, int b, @checked int c, int d}) {}
+}
+
+class Inherited extends Direct {}
+
+// ---
+
+class Override1 {
+  void method(@checked int a, int b, int c, int d, int e) {}
+}
+
+class Override2 extends Override1 {
+  void method(int a, int b, @checked int c, int d, int e) {}
+}
+
+class Override3 extends Override2 {
+  void method(int a, int b, int c, int d, int e) {}
+}
+
+// ---
+
+abstract class Implement1 {
+  void method(@checked int a, int b, int c, int d, int e) {}
+}
+
+class Implement2 {
+  void method(int a, @checked int b, int c, int d, int e) {}
+}
+
+class Implement3 {
+  void method(int a, int b, @checked int c, int d, int e) {}
+}
+
+class Implement4 implements Implement3 {
+  void method(int a, int b, int c, @checked int d, int e) {}
+}
+
+class Implement5 implements Implement1, Implement2, Implement4 {
+  void method(int a, int b, int c, int d, @checked int e) {}
+}
+
+// ---
+
+class Interface1 {
+  void method(@checked int a, int b, int c, int d, int e) {}
+}
+
+class Interface2 {
+  void method(int a, @checked int b, int c, int d, int e) {}
+}
+
+class Mixin1 {
+  void method(int a, int b, @checked int c, int d, int e) {}
+}
+
+class Mixin2 {
+  void method(int a, int b, int c, @checked int d, int e) {}
+}
+
+class Superclass {
+  void method(int a, int b, int c, int d, @checked int e) {}
+}
+
+class Mixed extends Superclass with Mixin1, Mixin2 implements Interface1, Interface2 {}
+
+void main() {
+  testDirect();
+  testInherited();
+  testOverriden();
+  testImplemented();
+  testMixed();
+}
+
+void testDirect() {
+  var positional = new Direct().positional;
+  Expect.isTrue(positional is TakeInts);
+  Expect.isTrue(positional is TakeObjectsAndInts);
+
+  var optional = new Direct().optional;
+  Expect.isTrue(optional is TakeOptionalInts);
+  Expect.isTrue(optional is TakeOptionalObjectsAndInts);
+
+  var named = new Direct().named;
+  Expect.isTrue(named is TakeNamedInts);
+  Expect.isTrue(named is TakeNamedObjectsAndInts);
+}
+
+void testInherited() {
+  var positional = new Inherited().positional;
+  Expect.isTrue(positional is TakeInts);
+  Expect.isTrue(positional is TakeObjectsAndInts);
+
+  var optional = new Inherited().optional;
+  Expect.isTrue(optional is TakeOptionalInts);
+  Expect.isTrue(optional is TakeOptionalObjectsAndInts);
+
+  var named = new Inherited().named;
+  Expect.isTrue(named is TakeNamedInts);
+  Expect.isTrue(named is TakeNamedObjectsAndInts);
+}
+
+void testOverriden() {
+  var method2 = new Override2().method;
+  Expect.isTrue(method2 is TakeInts);
+  Expect.isTrue(method2 is TakeObjectsAndInts);
+
+  var method3 = new Override3().method;
+  Expect.isTrue(method3 is TakeInts);
+  Expect.isTrue(method3 is TakeObjectsAndInts);
+}
+
+void testImplemented() {
+  var method = new Implement5().method;
+  Expect.isTrue(method is TakeInts);
+  Expect.isTrue(method is TakeObjects);
+}
+
+void testMixed() {
+  // TODO(rnystrom): https://github.com/dart-lang/sdk/issues/28395
+  // var method = new Mixed().method;
+  // Expect.isTrue(method is TakeInts);
+  // Expect.isTrue(method is TakeObjects);
+}