#1258. Added test for a generic enum which does have a regular-bounde…

…d instantiate-to-bounds result

LanguageFeatures/Enhanced-Enum/semantics_A13_t01.dart

@@ -28,6 +28,7 @@ enum E<Y extends A<Y>> {
 // [cfe] unspecified
   e1<Never>();
 }
+
 main() {
   E.e1;
 }

LanguageFeatures/Enhanced-Enum/semantics_A13_t02.dart

@@ -0,0 +1,29 @@
+// Copyright (c) 2022, 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 If the resulting class would have any naming conflicts, or other
+/// compile-time errors, the enum declaration is invalid and a compile-time
+/// error occurs. Such errors include, but are not limited to:
+/// ...
+/// Declaring a generic enum which does not have a regular-bounded
+/// instantiate-to-bounds result and that has an enum value declaration omitting
+/// the type arguments and not having arguments from which type arguments can be
+/// inferred. (For example enum EnumName<F extends C<F>> { foo; } would
+/// introduce an implicit static const foo = EnumName(0, "foo"); declaration
+/// where the constructor invocation requires a regular-bounded
+/// instantiate-to-bounds result).
+///
+/// @description Check that it is no compile-time error to declare a generic
+/// enum which does have a regular-bounded instantiate-to-bounds result
+/// @author [email protected]
+
+// SharedOptions=--enable-experiment=enhanced-enums
+
+enum E<Y extends Y Function(Y)> {
+  e1<Never>();
+}
+
+main() {
+  print(E.e1);
+}