#2559. Add tests for enum with empty list of values (#3066)

Language/Enums/syntax_t02.dart

@@ -7,16 +7,24 @@
 ///  enumType:
 ///  metadata enum id ‘{’ id [‘, ’ id]* [‘, ’] ‘}’
 ///  ;
+///
 /// @description Checks that it is compile-time error if enum does not declare
-/// any member
+/// any member.
 /// @author [email protected]
 
+enum E1 {}
+//   ^^
+// [analyzer] unspecified
+// [cfe] unspecified
 
-enum E {}
-//      ^
+enum E2 {
+//   ^^
 // [analyzer] unspecified
 // [cfe] unspecified
+  ;
+}
 
 main() {
-  E e;
+  print(E1);
+  print(E2);
 }

LanguageFeatures/Augmentation-libraries/augmenting_enum_values_A03_t04.dart

@@ -9,6 +9,7 @@
 /// @description Checks that it is a syntax error if an enum augmentation
 /// contains no any values.
 /// @author [email protected]
+/// @issue 56883
 
 // SharedOptions=--enable-experiment=macros
 

LanguageFeatures/Augmentation-libraries/augmenting_enum_values_A03_t05.dart

@@ -0,0 +1,42 @@
+// 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 New enum values may be defined in an augmenting enum, and they
+/// will be appended to the current values of the declaration in augmentation
+/// application order.
+///
+/// @description Checks that it is a syntax error if an enum augmentation
+/// contains an empty list of values.
+/// @author [email protected]
+/// @issue 56883
+
+// SharedOptions=--enable-experiment=macros
+
+enum E1 {
+  e0;
+}
+
+augment enum E1 {
+  ;
+//^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+enum E2 {
+  e0;
+}
+
+augment enum E2 {
+  ;
+//^
+// [analyzer] unspecified
+// [cfe] unspecified
+  void foo() {}
+}
+
+main() {
+  print(E1);
+  print(E2);
+}