diff --git a/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t06.dart b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t06.dart
index c1b2dc3e7e..a387920d32 100644
--- a/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t06.dart
+++ b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t06.dart
@@ -47,7 +47,7 @@ class C2 implements I1, I2, I3 {
 // [cfe] unspecified
 
   void m2(int v1, {String s0 = ""}) {}
-//     ^
+//     ^^
 // [analyzer] unspecified
 // [cfe] unspecified
 }
diff --git a/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t19.dart b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t19.dart
new file mode 100644
index 0000000000..8022647214
--- /dev/null
+++ b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t19.dart
@@ -0,0 +1,39 @@
+// Copyright (c) 2023, 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.
+
+/// @assertion Let m and m′ be member signatures with the same name id. Then m
+/// is a correct override of m′ iff the following criteria are all satisfied:
+/// ...
+/// • If m and m′ are both methods or both setters: Let F be the function type
+/// of m except that the parameter type is the built-in class Object for each
+/// parameter of m which is covariant-by-declaration. Let F′ be the function
+/// type of m′. F must then be a subtype of F′.
+///
+/// @description Checks that it is a compile-time error if `m` and `m′` are both
+/// setters and function type `m` is not a subtype of `m′`. Test `implements`
+/// clause
+/// @author sgrekhov22@gmail.com
+
+interface class I {
+  void set m(num n) {}
+}
+
+class C implements I {
+  void set m(int i) {}
+//         ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+mixin M implements I {
+  void set m(int i) {}
+//         ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(C);
+  print(M);
+}
diff --git a/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t20.dart b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t20.dart
new file mode 100644
index 0000000000..58a8ee06e0
--- /dev/null
+++ b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t20.dart
@@ -0,0 +1,43 @@
+// Copyright (c) 2023, 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.
+
+/// @assertion Let m and m′ be member signatures with the same name id. Then m
+/// is a correct override of m′ iff the following criteria are all satisfied:
+/// ...
+/// • If m and m′ are both methods or both setters: Let F be the function type
+/// of m except that the parameter type is the built-in class Object for each
+/// parameter of m which is covariant-by-declaration. Let F′ be the function
+/// type of m′. F must then be a subtype of F′.
+///
+/// @description Checks that it is a compile-time error if `m` and `m′` are both
+/// setters and function type `m` is not a subtype of `m′`. Test `implements`
+/// clause
+/// @author sgrekhov22@gmail.com
+
+interface class I1 {
+  void set m(int i) {}
+}
+
+interface class I2 {
+  void set m(Object i) {}
+}
+
+class C implements I1, I2 {
+  void set m(num i) {}
+//         ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+mixin M implements I1, I2 {
+  void set m(num i) {}
+//         ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(C);
+  print(M);
+}
diff --git a/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t21.dart b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t21.dart
new file mode 100644
index 0000000000..3608c54075
--- /dev/null
+++ b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t21.dart
@@ -0,0 +1,35 @@
+// Copyright (c) 2023, 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.
+
+/// @assertion Let m and m′ be member signatures with the same name id. Then m
+/// is a correct override of m′ iff the following criteria are all satisfied:
+/// ...
+/// • If m and m′ are both methods or both setters: Let F be the function type
+/// of m except that the parameter type is the built-in class Object for each
+/// parameter of m which is covariant-by-declaration. Let F′ be the function
+/// type of m′. F must then be a subtype of F′.
+///
+/// @description Checks that it is not an error if `m` and `m′` are both setters
+/// and function type `m` is a subtype of `m′. Test `implements` clause
+/// @author sgrekhov22@gmail.com
+
+interface class I {
+  void set m1(num v1) {}
+  void set m2(covariant int v1) {}
+}
+
+class C implements I {
+  void set m1(covariant int i) {}
+  void set m2(num i) {}
+}
+
+mixin M implements I {
+  void set m1(covariant int i) {}
+  void set m2(num i) {}
+}
+
+main() {
+  print(C);
+  print(M);
+}
diff --git a/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t22.dart b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t22.dart
new file mode 100644
index 0000000000..b8c48b0048
--- /dev/null
+++ b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t22.dart
@@ -0,0 +1,36 @@
+// Copyright (c) 2023, 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.
+
+/// @assertion Let m and m′ be member signatures with the same name id. Then m
+/// is a correct override of m′ iff the following criteria are all satisfied:
+/// ...
+/// • If m and m′ are both methods or both setters: Let F be the function type
+/// of m except that the parameter type is the built-in class Object for each
+/// parameter of m which is covariant-by-declaration. Let F′ be the function
+/// type of m′. F must then be a subtype of F′.
+///
+/// @description Checks that it is not an error if `m` and `m′` are both setters
+/// and function type `m` is a subtype of `m′. Test `implements` clause
+/// @author sgrekhov22@gmail.com
+
+interface class I1 {
+  void set m(num v1) {}
+}
+
+interface class I2 {
+  void set m(covariant int v1) {}
+}
+
+class C implements I1, I2 {
+  void set m(covariant int i) {}
+}
+
+mixin M implements I1, I2 {
+  void set m(num i) {}
+}
+
+main() {
+  print(C);
+  print(M);
+}
diff --git a/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t23.dart b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t23.dart
new file mode 100644
index 0000000000..b425a52a03
--- /dev/null
+++ b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t23.dart
@@ -0,0 +1,50 @@
+// Copyright (c) 2023, 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.
+
+/// @assertion Let m and m′ be member signatures with the same name id. Then m
+/// is a correct override of m′ iff the following criteria are all satisfied:
+/// ...
+/// • If m and m′ are both methods or both setters: Let F be the function type
+/// of m except that the parameter type is the built-in class Object for each
+/// parameter of m which is covariant-by-declaration. Let F′ be the function
+/// type of m′. F must then be a subtype of F′.
+///
+/// @description Checks that it is a compile-time error if `m` and `m′` are both
+/// setters and function type `m` is not a subtype of `m′. Test `implements`
+/// clause
+/// @author sgrekhov22@gmail.com
+
+interface class I {
+  void set m1(num v1) {}
+  void set m2(covariant int v1) {}
+}
+
+class C implements I {
+  void set m1(covariant String i) {}
+//         ^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void set m2(String i) {}
+//         ^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+mixin M implements I {
+  void set m1(covariant String i) {}
+//         ^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void set m2(String i) {}
+//         ^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(C);
+  print(M);
+}
diff --git a/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t24.dart b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t24.dart
new file mode 100644
index 0000000000..664ca6e24c
--- /dev/null
+++ b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t24.dart
@@ -0,0 +1,39 @@
+// Copyright (c) 2023, 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.
+
+/// @assertion Let m and m′ be member signatures with the same name id. Then m
+/// is a correct override of m′ iff the following criteria are all satisfied:
+/// ...
+/// • If m and m′ are both methods or both setters: Let F be the function type
+/// of m except that the parameter type is the built-in class Object for each
+/// parameter of m which is covariant-by-declaration. Let F′ be the function
+/// type of m′. F must then be a subtype of F′.
+///
+/// @description Checks that it is a compile-time error if `m` and `m′` are both
+/// setters and function type `m` is not a subtype of `m′`. Test `extends` and
+/// `on` clauses
+/// @author sgrekhov22@gmail.com
+
+interface class I {
+  void set m(num n) {}
+}
+
+class C extends I {
+  void set m(int i) {}
+//         ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+mixin M on I {
+  void set m(int i) {}
+//         ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(C);
+  print(M);
+}
diff --git a/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t25.dart b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t25.dart
new file mode 100644
index 0000000000..1a2040352c
--- /dev/null
+++ b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t25.dart
@@ -0,0 +1,43 @@
+// Copyright (c) 2023, 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.
+
+/// @assertion Let m and m′ be member signatures with the same name id. Then m
+/// is a correct override of m′ iff the following criteria are all satisfied:
+/// ...
+/// • If m and m′ are both methods or both setters: Let F be the function type
+/// of m except that the parameter type is the built-in class Object for each
+/// parameter of m which is covariant-by-declaration. Let F′ be the function
+/// type of m′. F must then be a subtype of F′.
+///
+/// @description Checks that it is a compile-time error if `m` and `m′` are both
+/// setters and function type `m` is not a subtype of `m′`. Test `extends` and
+/// `on` clauses
+/// @author sgrekhov22@gmail.com
+
+interface class I1 {
+  void set m(int i) {}
+}
+
+interface class I2 {
+  void set m(Object i) {}
+}
+
+class C extends I1 implements I2 {
+  void set m(num i) {}
+//         ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+mixin M on I2 implements I1 {
+  void set m(num i) {}
+//         ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(C);
+  print(M);
+}
diff --git a/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t26.dart b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t26.dart
new file mode 100644
index 0000000000..4c5ff37561
--- /dev/null
+++ b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t26.dart
@@ -0,0 +1,35 @@
+// Copyright (c) 2023, 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.
+
+/// @assertion Let m and m′ be member signatures with the same name id. Then m
+/// is a correct override of m′ iff the following criteria are all satisfied:
+/// ...
+/// • If m and m′ are both methods or both setters: Let F be the function type
+/// of m except that the parameter type is the built-in class Object for each
+/// parameter of m which is covariant-by-declaration. Let F′ be the function
+/// type of m′. F must then be a subtype of F′.
+///
+/// @description Checks that it is not an error if `m` and `m′` are both setters
+/// and function type `m` is a subtype of `m′. Test `extends` and `on` clauses
+/// @author sgrekhov22@gmail.com
+
+interface class I {
+  void set m1(num v1) {}
+  void set m2(covariant int v1) {}
+}
+
+class C extends I {
+  void set m1(covariant int i) {}
+  void set m2(num i) {}
+}
+
+mixin M on I {
+  void set m1(covariant int i) {}
+  void set m2(num i) {}
+}
+
+main() {
+  print(C);
+  print(M);
+}
diff --git a/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t27.dart b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t27.dart
new file mode 100644
index 0000000000..7160ca9592
--- /dev/null
+++ b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t27.dart
@@ -0,0 +1,36 @@
+// Copyright (c) 2023, 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.
+
+/// @assertion Let m and m′ be member signatures with the same name id. Then m
+/// is a correct override of m′ iff the following criteria are all satisfied:
+/// ...
+/// • If m and m′ are both methods or both setters: Let F be the function type
+/// of m except that the parameter type is the built-in class Object for each
+/// parameter of m which is covariant-by-declaration. Let F′ be the function
+/// type of m′. F must then be a subtype of F′.
+///
+/// @description Checks that it is not an error if `m` and `m′` are both setters
+/// and function type `m` is a subtype of `m′. Test `extends` and `on` clauses
+/// @author sgrekhov22@gmail.com
+
+interface class I1 {
+  void set m(num v1) {}
+}
+
+interface class I2 {
+  void set m(covariant int v1) {}
+}
+
+class C extends I1 implements I2 {
+  void set m(covariant int i) {}
+}
+
+mixin M on I2 implements I1 {
+  void set m(num i) {}
+}
+
+main() {
+  print(C);
+  print(M);
+}
diff --git a/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t28.dart b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t28.dart
new file mode 100644
index 0000000000..a1a41d0a11
--- /dev/null
+++ b/Language/Interfaces/Correct_Member_Overrides/correct_member_overrides_A03_t28.dart
@@ -0,0 +1,50 @@
+// Copyright (c) 2023, 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.
+
+/// @assertion Let m and m′ be member signatures with the same name id. Then m
+/// is a correct override of m′ iff the following criteria are all satisfied:
+/// ...
+/// • If m and m′ are both methods or both setters: Let F be the function type
+/// of m except that the parameter type is the built-in class Object for each
+/// parameter of m which is covariant-by-declaration. Let F′ be the function
+/// type of m′. F must then be a subtype of F′.
+///
+/// @description Checks that it is a compile-time error if `m` and `m′` are both
+/// setters and function type `m` is not a subtype of `m′. Test `extends` and
+/// `on` clauses
+/// @author sgrekhov22@gmail.com
+
+interface class I {
+  void set m1(num v1) {}
+  void set m2(covariant int v1) {}
+}
+
+class C extends I {
+  void set m1(covariant String i) {}
+//         ^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void set m2(String i) {}
+//         ^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+mixin M on I {
+  void set m1(covariant String i) {}
+//         ^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void set m2(String i) {}
+//         ^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(C);
+  print(M);
+}