diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A07_t01.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A07_t01.dart
index 2b4b41303a..d36c6db9b9 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A07_t01.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A07_t01.dart
@@ -32,6 +32,10 @@ extension Ext on A {
   A test() => this;
 }
 
+extension type ET(int _) {
+  ET test() => this;
+}
+
 class MA = Object with M;
 
 main() {
@@ -39,4 +43,5 @@ main() {
   MA().test();
   E.e0.test();
   A().test();
+  ET(0).test();
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A07_t01_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A07_t01_lib.dart
index 604d8c46cf..889d61d2e6 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A07_t01_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A07_t01_lib.dart
@@ -42,3 +42,10 @@ augment extension Ext {
     return this;
   }
 }
+
+augment extension type ET {
+  augment ET test() {
+    Expect.identical(this, augmented());
+    return this;
+  }
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t01.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t01.dart
index 932f1603ad..6004b055a0 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t01.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t01.dart
@@ -31,4 +31,6 @@ main() {
   Expect.equals("augmented", E.e1.instanceMethod());
   Expect.equals("augmented", Ext.staticMethod());
   Expect.equals("augmented", A().instanceMethod());
+  Expect.equals("augmented", ET.staticMethod());
+  Expect.equals("augmented", ET(0).instanceMethod());
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t01_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t01_lib.dart
index 50ef1ddab1..e6a0dd1131 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t01_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t01_lib.dart
@@ -41,3 +41,8 @@ extension Ext on A {
   static String staticMethod() => augmented();
   String instanceMethod() => augmented();
 }
+
+extension type ET(int _) {
+  static String staticMethod() => augmented();
+  String instanceMethod() => augmented();
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t02.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t02.dart
index ba1f9e5675..4f85bb3104 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t02.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t02.dart
@@ -31,4 +31,6 @@ main() {
   Expect.equals("augmented", E.e1.instanceMethod());
   Expect.equals("augmented", Ext.staticMethod());
   Expect.equals("augmented", A().instanceMethod());
+  Expect.equals("augmented", ET.staticMethod());
+  Expect.equals("augmented", ET(0).instanceMethod());
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t02_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t02_lib.dart
index 4d54cbabd3..baaf2d9e07 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t02_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t02_lib.dart
@@ -41,3 +41,8 @@ extension Ext on A {
   static String staticMethod() => augmented;
   String instanceMethod() => augmented;
 }
+
+extension type ET(int _) {
+  static String staticMethod() => augmented;
+  String instanceMethod() => augmented;
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t03.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t03.dart
index 3749780c1c..7014f4bcf4 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t03.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t03.dart
@@ -31,4 +31,6 @@ main() {
   Expect.equals("augmented", E.e1.instanceMethod());
   Expect.equals("augmented", Ext.staticMethod());
   Expect.equals("augmented", A().instanceMethod());
+  Expect.equals("augmented", ET.staticMethod());
+  Expect.equals("augmented", ET(0).instanceMethod());
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t03_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t03_lib.dart
index beb9eefc9a..df49978f88 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t03_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t03_lib.dart
@@ -41,3 +41,8 @@ extension Ext on A {
   static String staticMethod() => augmented;
   String instanceMethod() => augmented;
 }
+
+extension type ET(int _) {
+  static String staticMethod() => augmented;
+  String instanceMethod() => augmented;
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t04.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t04.dart
index 9a1581241a..e42f6ed22b 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t04.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t04.dart
@@ -43,4 +43,8 @@ main() {
   Expect.equals("augmented = Ext.staticMethod", _log);
   A().instanceMethod();
   Expect.equals("augmented = Ext.instanceMethod", _log);
+  ET.staticMethod();
+  Expect.equals("augmented = ET.staticMethod", _log);
+  ET(0).instanceMethod();
+  Expect.equals("augmented = ET.instanceMethod", _log);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t04_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t04_lib.dart
index 9ebb946fbc..6aec7333ad 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t04_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A08_t04_lib.dart
@@ -59,3 +59,12 @@ extension Ext on A {
     augmented = "Ext.instanceMethod";
   }
 }
+
+extension type ET(int _) {
+  static void staticMethod() {
+    augmented = "ET.staticMethod";
+  }
+  void instanceMethod() {
+    augmented = "ET.instanceMethod";
+  }
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t01.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t01.dart
index be591c4124..aab29735f9 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t01.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t01.dart
@@ -23,6 +23,7 @@ enum E {e0;}
 
 class A {}
 extension Ext on A {}
+extension type ET(int _) {}
 
 main() {
   print(C1);
@@ -31,4 +32,5 @@ main() {
   print(M2);
   print(E);
   print(A);
+  print(ET);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t01_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t01_lib.dart
index 556b97d4b6..0094af88e8 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t01_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t01_lib.dart
@@ -57,3 +57,10 @@ augment extension Ext {
 // [analyzer] unspecified
 // [cfe] unspecified
 }
+
+augment extension type ET {
+  static String augmented = "static";
+//              ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t02.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t02.dart
index 5d8f21015b..2002912cf0 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t02.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t02.dart
@@ -25,6 +25,8 @@ enum E2 {e0;}
 class A {}
 extension Ext1 on A {}
 extension Ext2 on A {}
+extension type ET1(int _) {}
+extension type ET2(int _) {}
 
 main() {
   print(C1);
@@ -34,4 +36,6 @@ main() {
   print(E1);
   print(E2);
   print(A);
+  print(ET1);
+  print(ET2);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t02_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t02_lib.dart
index 8bb8116d9d..cc603e90bf 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t02_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t02_lib.dart
@@ -72,3 +72,17 @@ augment extension Ext2 {
 // [analyzer] unspecified
 // [cfe] unspecified
 }
+
+augment extension type ET1 {
+  static String get augmented => "static";
+//                  ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+augment extension type ET2 {
+  String get augmented => "instance";
+//           ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t03.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t03.dart
index a6c63f4c47..3b92bb1f4e 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t03.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t03.dart
@@ -25,6 +25,8 @@ enum E2 {e0;}
 class A {}
 extension Ext1 on A {}
 extension Ext2 on A {}
+extension type ET1(int _) {}
+extension type ET2(int _) {}
 
 main() {
   print(C1);
@@ -34,4 +36,6 @@ main() {
   print(E1);
   print(E2);
   print(A);
+  print(ET1);
+  print(ET2);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t03_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t03_lib.dart
index 6eaecd41af..7d8d9d708e 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t03_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t03_lib.dart
@@ -72,3 +72,17 @@ augment extension Ext2 {
 // [analyzer] unspecified
 // [cfe] unspecified
 }
+
+augment extension type ET1 {
+  static String augmented() => "static";
+//              ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+augment extension type ET2 {
+  String augmented() => "instance";
+//       ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t04.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t04.dart
index 9c1a5f4f6a..c11499844e 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t04.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t04.dart
@@ -25,6 +25,8 @@ enum E2 {e0;}
 class A {}
 extension Ext1 on A {}
 extension Ext2 on A {}
+extension type ET1(int _) {}
+extension type ET2(int _) {}
 
 main() {
   print(C1);
@@ -34,4 +36,6 @@ main() {
   print(E1);
   print(E2);
   print(A);
+  print(ET1);
+  print(ET2);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t04_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t04_lib.dart
index b19bbfd8ee..c623cba769 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t04_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t04_lib.dart
@@ -72,3 +72,17 @@ augment extension Ext2 {
 // [analyzer] unspecified
 // [cfe] unspecified
 }
+
+augment extension type ET1 {
+  static void set augmented(String _) {}
+//                ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+augment extension type ET2 {
+  void set augmented(String _) {}
+//         ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t05.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t05.dart
index 8f8da5454e..016cb45a6b 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t05.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t05.dart
@@ -21,10 +21,12 @@ enum E {e0;}
 
 class A {}
 extension Ext on A {}
+extension type ET(int _) {}
 
 main() {
   print(C);
   print(M);
   print(E);
   print(A);
+  print(ET);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t05_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t05_lib.dart
index 5a9fbbe62c..66d86497a3 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t05_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t05_lib.dart
@@ -63,3 +63,15 @@ augment extension Ext {
 // [analyzer] unspecified
 // [cfe] unspecified
 }
+
+augment extension type ET {
+  static void staticMethod<augmented>(int v) {}
+//                         ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void instanceMethod<augmented>(int v) {}
+//                    ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t06.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t06.dart
index 041f35082a..4c0a4fa2f1 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t06.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t06.dart
@@ -23,10 +23,12 @@ enum E {e0;}
 
 class A {}
 extension Ext on A {}
+extension type ET(int _) {}
 
 main() {
   print(C);
   print(M);
   print(E);
   print(A);
+  print(ET);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t06_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t06_lib.dart
index 6c2854c0b0..51ccc895e4 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t06_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t06_lib.dart
@@ -138,3 +138,30 @@ augment extension Ext {
 // [analyzer] unspecified
 // [cfe] unspecified
 }
+
+augment extension type ET {
+  static augmented? staticVariable = null;
+//       ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  static augmented? get staticGetter => null;
+//       ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  static augmented? staticMethod() => null;
+//       ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  augmented? get instanceGetter => null;
+//^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  augmented? instanceMethod() => null;
+//^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t07.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t07.dart
index c1ebc1e436..51afd2512e 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t07.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t07.dart
@@ -23,10 +23,12 @@ enum E {e0;}
 
 class A {}
 extension Ext on A {}
+extension type ET(int _) {}
 
 main() {
   print(C);
   print(M);
   print(E);
   print(A);
+  print(ET);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t07_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t07_lib.dart
index 1f78eaa48c..bedfcb2b22 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t07_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t07_lib.dart
@@ -21,8 +21,8 @@ augment class C {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  static void staticSetter(augmented _) {}
-//                         ^^^^^^^^^
+  static void set staticSetter(augmented _) {}
+//                             ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 
@@ -31,8 +31,8 @@ augment class C {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  void instanceSetter(augmented _) {}
-//                    ^^^^^^^^^
+  void set instanceSetter(augmented _) {}
+//                        ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 }
@@ -43,8 +43,8 @@ augment mixin M {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  static void staticSetter(augmented _) {}
-//                         ^^^^^^^^^
+  static void set staticSetter(augmented _) {}
+//                             ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 
@@ -53,8 +53,8 @@ augment mixin M {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  void instanceSetter(augmented _) {}
-//                    ^^^^^^^^^
+  void set instanceSetter(augmented _) {}
+//                        ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 }
@@ -66,8 +66,8 @@ augment enum E {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  static void staticSetter(augmented _) {}
-//                         ^^^^^^^^^
+  static void set staticSetter(augmented _) {}
+//                             ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 
@@ -76,8 +76,8 @@ augment enum E {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  void instanceSetter(augmented _) {}
-//                    ^^^^^^^^^
+  void set instanceSetter(augmented _) {}
+//                        ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 }
@@ -88,8 +88,8 @@ augment extension Ext {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  static void staticSetter(augmented _) {}
-//                         ^^^^^^^^^
+  static void set staticSetter(augmented _) {}
+//                             ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 
@@ -98,8 +98,30 @@ augment extension Ext {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  void instanceSetter(augmented _) {}
+  void set instanceSetter(augmented _) {}
+//                        ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+augment extension ET {
+  static void staticMethod(augmented _) {}
+//                         ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  static void set staticSetter(augmented _) {}
+//                             ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void instanceMethod(augmented _) {}
 //                    ^^^^^^^^^
 // [analyzer] unspecified
+// [cfe] unspecified
+
+  void set instanceSetter(augmented _) {}
+//                        ^^^^^^^^^
+// [analyzer] unspecified
 // [cfe] unspecified
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t08.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t08.dart
index 2073e89d53..b5e3f1e282 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t08.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t08.dart
@@ -21,10 +21,12 @@ enum E {e0;}
 
 class A {}
 extension Ext on A {}
+extension type ET(int _) {}
 
 main() {
   print(C);
   print(M);
   print(E);
   print(A);
+  print(ET);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t08_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t08_lib.dart
index e3f96bd143..a18e507df4 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t08_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t08_lib.dart
@@ -31,8 +31,8 @@ augment class C {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  static void staticSetter(int augmented) {}
-//                             ^^^^^^^^^
+  static void set staticSetter(int augmented) {}
+//                                 ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 
@@ -51,8 +51,8 @@ augment class C {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  void instanceSetter(int augmented) {}
-//                        ^^^^^^^^^
+  void set instanceSetter(int augmented) {}
+//                            ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 }
@@ -73,8 +73,8 @@ augment mixin M {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  static void staticSetter(int augmented) {}
-//                             ^^^^^^^^^
+  static void set staticSetter(int augmented) {}
+//                                 ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 
@@ -93,8 +93,8 @@ augment mixin M {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  void instanceSetter(int augmented) {}
-//                        ^^^^^^^^^
+  void set instanceSetter(int augmented) {}
+//                            ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 }
@@ -116,8 +116,8 @@ augment enum E {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  static void staticSetter(int augmented) {}
-//                             ^^^^^^^^^
+  static void set staticSetter(int augmented) {}
+//                                 ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 
@@ -136,8 +136,8 @@ augment enum E {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  void instanceSetter(int augmented) {}
-//                        ^^^^^^^^^
+  void set instanceSetter(int augmented) {}
+//                            ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 }
@@ -158,9 +158,51 @@ augment extension Ext {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  static void staticSetter(int augmented) {}
+  static void set staticSetter(int augmented) {}
+//                                 ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void instanceMethod1(int augmented) {}
+//                         ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void instanceMethod2([int augmented = 0]) {}
+//                          ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void instanceMethod3({int augmented = 0}) {}
+//                          ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void set instanceSetter(int augmented) {}
+//                            ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+augment extension type ET {
+  static void staticMethod1(int augmented) {}
 //                             ^^^^^^^^^
 // [analyzer] unspecified
+// [cfe] unspecified
+
+  static void staticMethod2([int augmented = 0]) {}
+//                               ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  static void staticMethod3({int augmented = 0}) {}
+//                               ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  static void set staticSetter(int augmented) {}
+//                                 ^^^^^^^^^
+// [analyzer] unspecified
 // [cfe] unspecified
 
   void instanceMethod1(int augmented) {}
@@ -178,8 +220,8 @@ augment extension Ext {
 // [analyzer] unspecified
 // [cfe] unspecified
 
-  void instanceSetter(int augmented) {}
-//                        ^^^^^^^^^
+  void set instanceSetter(int augmented) {}
+//                            ^^^^^^^^^
 // [analyzer] unspecified
 // [cfe] unspecified
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t09.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t09.dart
index 86a3dbb6f1..3a8debaa2c 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t09.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t09.dart
@@ -21,10 +21,12 @@ enum E {e0;}
 
 class A {}
 extension Ext on A {}
+extension type ET(int _) {}
 
 main() {
   print(C);
   print(M);
   print(E);
   print(A);
+  print(ET);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t09_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t09_lib.dart
index 05fb575272..82c247fd52 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t09_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t09_lib.dart
@@ -138,3 +138,30 @@ augment extension Ext {
 // [analyzer] unspecified
 // [cfe] unspecified
 }
+
+augment extension type ET {
+  static ({int augmented})? staticVariable = null;
+//             ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  static ({int augmented})? staticMethod() => null;
+//             ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  static ({int augmented})? get staticGetter => null;
+//             ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  ({int augmented})? instanceMethod(int augmented) => null;
+//      ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  ({int augmented})? get instanceGetter => null;
+//      ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t10.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t10.dart
index 0ceeb6148d..ef3665f6ab 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t10.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t10.dart
@@ -21,10 +21,12 @@ enum E {e0;}
 
 class A {}
 extension Ext on A {}
+extension type ET(int _) {}
 
 main() {
   print(C);
   print(M);
   print(E);
   print(A);
+  print(ET);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t10_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t10_lib.dart
index 106ad7c8a6..376f8c5be7 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t10_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t10_lib.dart
@@ -103,3 +103,25 @@ augment extension Ext {
 // [analyzer] unspecified
 // [cfe] unspecified
 }
+
+augment extension type ET {
+  static void staticMethod(({int augmented}) r) {}
+//                               ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  static void set staticSetter(({int augmented}) r) {}
+//                                   ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void instanceMethod(({int augmented}) r) {}
+//                          ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void set instanceSetter(({int augmented}) r) {}
+//                              ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t11.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t11.dart
index 49e1c53a1b..b46bf67aea 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t11.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t11.dart
@@ -28,10 +28,12 @@ enum E {
 class A {}
 
 extension Ext on A {}
+extension type ET(int _) {}
 
 main() {
   print(C);
   print(M);
   print(E);
   print(A);
+  print(ET);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t11_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t11_lib.dart
index e3f79fb844..8324b5ed93 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t11_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t11_lib.dart
@@ -60,3 +60,14 @@ augment extension Ext {
 // [analyzer] unspecified
 // [cfe] unspecified
 }
+
+augment extension type ET {
+  static void staticMethod<T extends augmented>() {}
+//                                   ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  void instanceMethod<T extends augmented>() {}
+//                              ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t13.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t13.dart
index 792fc8df6c..349b722dc8 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t13.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t13.dart
@@ -24,10 +24,12 @@ enum E {e0;}
 
 class A {}
 extension Ext on A {}
+extension type ET(int _) {}
 
 main() {
   print(C);
   print(M);
   print(E);
   print(A);
+  print(ET);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t13_lib.dart b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t13_lib.dart
index 56a4a862ef..f7c4059e58 100644
--- a/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t13_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmented_expression_A09_t13_lib.dart
@@ -104,3 +104,25 @@ augment extension Ext {
 // [analyzer] unspecified
 // [cfe] unspecified
 }
+
+augment extension type ET {
+  static void staticMethod1([String s = augmented]) {}
+//                                      ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  static void staticMethod2({String s = augmented}) {}
+//                                      ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void instanceMethod1([String s = augmented]) {}
+//                                 ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  void instanceMethod2({String s = augmented}) {}
+//                                 ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A02_t02.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A02_t02.dart
new file mode 100644
index 0000000000..5ea7589fd3
--- /dev/null
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A02_t02.dart
@@ -0,0 +1,78 @@
+// Copyright (c) 2024, 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 It is a compile-time error if:
+/// ...
+/// - The augmenting constructor parameters specify any default values.
+///
+/// @description Checks that it is a compile-time error if the augmenting
+/// factory constructor parameters specify any default values.
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=macros
+
+class C {
+  C([int x = 0]);
+  C.c1({int x = 0});
+  factory C.c2([int x = 0]) => C(x);
+  factory C.c3({int x = 0}) => C.c1(x: x);
+}
+
+augment class C {
+  augment factory C.c2([int x = 0]);
+//                          ^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  augment factory C.c3({int x = 0});
+//                          ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+enum E {
+  e0(0);
+  const E([int x = 0]);
+  const E.c1({int x = 0});
+  factory E.c2([int x = 0]) => E.e0;
+  factory E.c3({int x = 0}) => E.e0;
+}
+
+augment enum E {
+  augment e0;
+  augment factory E.c2([int x = 0]);
+//                          ^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  augment factory E.c3({int x = 0});
+//                          ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+extension type ET(int id) {
+  ET.c1(this.id, [int x = 0]);
+  ET.c2(this.id, {int x = 0});
+  factory ET.c3(int id, [int x = 0]) => ET.c1(id, x);
+  factory ET.c4(int id, {int x = 0}) => ET.c2(id, x: x);
+}
+
+augment extension type ET {
+  augment factory ET.c3([int x = 0]);
+//                           ^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  augment factory ET.c4({int x = 0});
+//                           ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(C);
+  print(E);
+  print(ET);
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A03_t03.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A03_t03.dart
new file mode 100644
index 0000000000..fa035c1b55
--- /dev/null
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A03_t03.dart
@@ -0,0 +1,44 @@
+// Copyright (c) 2024, 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 It is a compile-time error if:
+/// ...
+/// - The introductory constructor is `const` and the augmenting constructor is
+///   not or vice versa.
+///
+/// @description Checks that it is a compile-time error if the introductory
+/// constructor is `const` and the augmenting constructor is not. Test factory
+/// constructors.
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=macros
+
+class C {
+  const C();
+  const factory C.foo() = C;
+}
+
+augment class C {
+  augment factory C.foo();
+//                ^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+extension type ET(int id) {
+  const ET.foo(this.id);
+  const factory ET.bar(int id) = ET.foo;
+}
+
+augment extension type ET {
+  augment factory ET.bar(int id);
+//                ^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(C);
+  print(ET);
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A03_t04.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A03_t04.dart
new file mode 100644
index 0000000000..448c0b52f8
--- /dev/null
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A03_t04.dart
@@ -0,0 +1,44 @@
+// Copyright (c) 2024, 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 It is a compile-time error if:
+/// ...
+/// - The introductory constructor is `const` and the augmenting constructor is
+///   not or vice versa.
+///
+/// @description Checks that it is a compile-time error if the augmenting
+/// constructor is `const` and the introductory constructor is not. Test factory
+/// constructors.
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=macros
+
+class C {
+  const C();
+  factory C.foo() = C;
+}
+
+augment class C {
+  augment const factory C.foo();
+//                      ^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+extension type ET(int id) {
+  const ET.foo(this.id);
+  factory ET.bar(int id) = ET.foo;
+}
+
+augment extension type ET {
+  augment const factory ET.bar(int id);
+//                      ^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(C);
+  print(ET);
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A06_t01.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A06_t01.dart
index a9b22d047f..3ec1552eae 100644
--- a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A06_t01.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A06_t01.dart
@@ -10,6 +10,7 @@
 /// @description Checks that it is a compile-time error if the resulting
 /// constructor has a redirecting initializer and other initializers.
 /// @author sgrekhov22@gmail.com
+/// @issue 57029
 
 // SharedOptions=--enable-experiment=macros
 
@@ -24,6 +25,25 @@ class C {
 // [cfe] unspecified
 }
 
+enum E {
+  e0(0), e1.foo();
+  final int x;
+  const E(this.x);
+  const E.foo(): this(0);
+//      ^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+extension type ET(int id) {
+  ET.foo(): this(0);
+//^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
 main() {
   print(C);
+  print(E);
+  print(ET);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A06_t01_lib.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A06_t01_lib.dart
index d17f573d7a..7196be8609 100644
--- a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A06_t01_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A06_t01_lib.dart
@@ -18,3 +18,12 @@ part of 'augmenting_constructors_A06_t01.dart';
 augment class C {
   augment C.foo(): x = 1;
 }
+
+augment enum E {
+  e2;
+  augment const E.foo(): x = 1;
+}
+
+augment extension type ET {
+  augment ET.foo(): id = 1;
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A06_t03.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A06_t03.dart
new file mode 100644
index 0000000000..6235fa6c5c
--- /dev/null
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A06_t03.dart
@@ -0,0 +1,35 @@
+// Copyright (c) 2024, 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 It is a compile-time error if:
+/// ...
+/// - The resulting constructor is not valid (has a redirecting initializer and
+///   other initializers, multiple super initializers, etc).
+///
+/// @description Checks that it is a compile-time error if the resulting
+/// constructor has a redirecting initializer and other initializers.
+/// @author sgrekhov22@gmail.com
+/// @issue 57029
+
+// SharedOptions=--enable-experiment=macros
+
+class A {
+  int x;
+  A([this.x = 0]);
+}
+
+class C extends A {
+  C(): super();
+//^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+augment class C {
+  augment C(): super(1);
+}
+
+main() {
+  print(C);
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A08_t01.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A08_t01.dart
index b8cda6bf56..34b55e468d 100644
--- a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A08_t01.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A08_t01.dart
@@ -24,6 +24,26 @@ class C {
 // [cfe] unspecified
 }
 
+enum E {
+  e0(0);
+  final int x;
+  const E(this.x);
+  const E.foo(): x = 1;
+//      ^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+extension type ET(int x) {
+  ET.foo(this.x);
+  ET.bar(): x = 1;
+//^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
 main() {
   print(C);
+  print(E);
+  print(ET);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A08_t01_lib.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A08_t01_lib.dart
index 46354eeae9..629677b792 100644
--- a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A08_t01_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A08_t01_lib.dart
@@ -18,3 +18,12 @@ part of 'augmenting_constructors_A08_t01.dart';
 augment class C {
   augment C.foo(): this(0);
 }
+
+augment enum E {
+  e1(1);
+  augment const E.foo(): this(0);
+}
+
+augment extension type ET {
+  augment ET.bar(): this(0);
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A11_t01.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A11_t01.dart
index a866d0cfc2..547b64c357 100644
--- a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A11_t01.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A11_t01.dart
@@ -12,6 +12,7 @@
 /// @description Checks that when `augmented()` is called in the body of an
 /// augmenting constructor initializer lists are not re-run.
 /// @author sgrekhov22@gmail.com
+/// @issue 56493
 
 // SharedOptions=--enable-experiment=macros
 
@@ -22,6 +23,10 @@ class C {
   C(): x = "Original";
 }
 
+extension type ET(String x) {
+  ET.foo(): x = "Original";
+}
+
 main() {
   C();
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A11_t01_lib.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A11_t01_lib.dart
index e000df10a4..440014a7f7 100644
--- a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A11_t01_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A11_t01_lib.dart
@@ -12,6 +12,7 @@
 /// @description Checks that when `augmented()` is called in the body of an
 /// augmenting constructor initializer lists are not re-run.
 /// @author sgrekhov22@gmail.com
+/// @issue 56493
 
 // SharedOptions=--enable-experiment=macros
 
@@ -29,3 +30,11 @@ augment class C {
     Expect.equals("y", y);
   }
 }
+
+augment extension type ET {
+  augment ET.foo(): x = "Augmented" {
+    Expect.equals("Augmented", x);
+    augmented();
+    Expect.equals("Augmented", x);
+  }
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A12_t01.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A12_t01.dart
index 7cae125a92..0008dec7bf 100644
--- a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A12_t01.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A12_t01.dart
@@ -27,6 +27,14 @@ class C {
   }
 }
 
+String log = "";
+
+extension type ET(int x) {
+  ET.foo(this.x, String s) {
+    log = s;
+  }
+}
+
 main() {
   C c1 = C("Original");
   Expect.equals("Augmented", c1.x);
@@ -34,4 +42,7 @@ main() {
   C c2 = C("Original", "Original");
   Expect.equals("Augmented", c2.x);
   Expect.equals("Augmented", c2.y);
+
+  ET et = ET.foo(42, "Original");
+  Expect.equals("Augmented", log);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A12_t01_lib.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A12_t01_lib.dart
index e1eaecd0ae..a13c41084f 100644
--- a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A12_t01_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A12_t01_lib.dart
@@ -24,3 +24,10 @@ augment class C {
     augmented();
   }
 }
+
+augment extension type ET {
+  augment ET.foo(this.x, String s) {
+    s = "Augmented";
+    augmented();
+  }
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t01.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t01.dart
index 023d85df50..d5e6276ffb 100644
--- a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t01.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t01.dart
@@ -25,6 +25,25 @@ class C {
   C.bar(int x, {required int y});
 }
 
+enum E {
+  e0(0), e1.foo(1, y: 2), e2.bar(3, y: 4);
+  final int x, y;
+  const E(this.x, [this.y = 0]);
+  const E.foo(int x, {int y = 0});
+  const E.bar(int x, {required int y});
+}
+
+int log = -1;
+
+extension type ET(int x) {
+  ET.foo(int x, int y) {
+    log = y;
+  }
+  ET.bar(int x, [int y = 0]);
+  ET.baz(int x, {int y = 0});
+  ET.qux(int x, {required int y});
+}
+
 main() {
   Expect.equals(1, C.foo(1).x);
   Expect.equals(0, C.foo(1).y);
@@ -32,4 +51,18 @@ main() {
   Expect.equals(2, C.foo(1, y: 2).y);
   Expect.equals(1, C.bar(1, y: 2).x);
   Expect.equals(2, C.bar(1, y: 2).y);
+
+  Expect.equals(1, E.e1.x);
+  Expect.equals(2, E.e1.y);
+  Expect.equals(3, E.e2.x);
+  Expect.equals(4, E.e2.y);
+
+  Expect.equals(2, ET.foo(1, 2).x);
+  Expect.equals(1, log);
+  Expect.equals(3, ET.bar(3, 4).x);
+  Expect.equals(4, log);
+  Expect.equals(5, ET.baz(5, y: 6).x);
+  Expect.equals(6, log);
+  Expect.equals(7, ET.qux(7, y: 8).x);
+  Expect.equals(8, log);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t01_lib.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t01_lib.dart
index 27977c2286..2f147dd4d6 100644
--- a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t01_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t01_lib.dart
@@ -21,3 +21,16 @@ augment class C {
   augment C.foo(int x, {int y}): this(x, y);
   augment C.bar(int x, {required int y}): this.foo(x, y: y);
 }
+
+augment enum E {
+  augment e0;
+  augment const E.foo(int x, {int y}): this(x, y);
+  augment const E.bar(int x, {required int y}): this.foo(x, y: y);
+}
+
+augment extension type ET {
+  augment ET.foo(int x, int y): this(x);
+  augment ET.bar(int x, [int y]): this.foo(x, y);
+  augment ET.baz(int x, {int y}): this.foo(x, y);
+  augment ET.qux(int x, {required int y}): this.foo(x, y);
+}
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t02.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t02.dart
index 7c6c91197d..aee9b8e320 100644
--- a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t02.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t02.dart
@@ -24,6 +24,21 @@ class C {
   C.bar(int x): this(x + 1);
 }
 
+enum E {
+  e0(0), e1.foo(1), e2.foo(2);
+  final int x;
+  const E(this.x);
+  const E.foo(int x): this(x + 1);
+  const E.bar(int x): this(x + 1);
+}
+
+extension type ET(int x) {
+  ET.foo(int x): this(x + 1);
+  ET.bar(int x): this(x + 1);
+}
+
 main() {
   Expect.equals(3, C.bar(1).x);
+  Expect.equals(3, E.e2.x);
+  Expect.equals(3, ET.bar(1).x);
 }
diff --git a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t02_lib.dart b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t02_lib.dart
index 3953343e42..14b9d1e4f6 100644
--- a/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t02_lib.dart
+++ b/LanguageFeatures/Augmentation-libraries/augmenting_constructors_A17_t02_lib.dart
@@ -19,3 +19,12 @@ part of 'augmenting_constructors_A17_t02.dart';
 augment class C {
   augment C.bar(int x): this.foo(x + 1);
 }
+
+augment enum E {
+  augment e0;
+  augment E.bar(int x): this.foo(x + 1);
+}
+
+augment extension type ET {
+  augment ET.bar(int x): this.foo(x + 1);
+}