Add compile-time errors for enums.

pkg/compiler/lib/src/warnings.dart

 // Copyright (c) 2011, 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.
 
 part of dart2js;
 
 const DONT_KNOW_HOW_TO_FIX = "";
 
 /**
  * The messages in this file should meet the following guide lines:
@@ skipping 779 matching lines @@
       examples: const ["""
 class C extends Object with String {}
 
 main() => new C();
 """, """
 typedef C = Object with String;
 
 main() => new C();
 """]);
 
+  static const MessageKind CANNOT_EXTEND_ENUM = const MessageKind(
+      "Class '#{className}' can't extend the type '#{enumType}' because "
+      "it is declared by an enum.",
+      options: const ['--enable-enum'],
+      howToFix: "Try making '#{enumType}' a normal class or removing the "
+        "'extends' clause.",
+      examples: const ["""
+enum Enum {}
+class A extends Enum {}
+main() => new A();"""]);
+
+  static const MessageKind CANNOT_IMPLEMENT_ENUM = const MessageKind(
+      "Class '#{className}' can't implement the type '#{enumType}' "
+      "because it is declared by an enum.",
+      options: const ['--enable-enum'],
+      howToFix: "Try making '#{enumType}' a normal class or removing the "
+        "type from the 'implements' clause.",
+      examples: const ["""
+enum Enum {}
+class A implements Enum {}
+main() => new A();"""]);
+
+  static const MessageKind CANNOT_MIXIN_ENUM = const MessageKind(
+      "Class '#{className}' can't mixin the type '#{enumType}' because it "
+      "is declared by an enum.",
+      options: const ['--enable-enum'],
+      howToFix: "Try making '#{enumType}' a normal class or removing the "
+        "type from the 'with' clause.",
+      examples: const ["""
+enum Enum {}
+class A extends Object with Enum {}
+main() => new A();"""]);
+
+  static const MessageKind CANNOT_INSTANTIATE_ENUM = const MessageKind(
+      "Enum type '#{enumName}' cannot be instantiated.",
+      options: const ['--enable-enum'],
+      howToFix: "Try making '#{enumType}' a normal class or use an enum "
+                "constant.",
+      examples: const ["""
+enum Enum {}
+main() => new Enum(0, '');""", """
+enum Enum {}
+main() => const Enum(0, '');"""]);
+
   static const MessageKind DUPLICATE_EXTENDS_IMPLEMENTS = const MessageKind(
       "'#{type}' can not be both extended and implemented.");
 
   static const MessageKind DUPLICATE_IMPLEMENTS = const MessageKind(
       "'#{type}' must not occur more than once "
       "in the implements clause.");
 
   static const MessageKind MULTI_INHERITANCE = const MessageKind(
       "Dart2js does not currently support inheritance of the same class with "
       "different type arguments: Both #{firstType} and #{secondType} are "
@@ skipping 1432 matching lines @@
   static String convertToString(value) {
     if (value is ErrorToken) {
       // Shouldn't happen.
       return value.assertionMessage;
     } else if (value is Token) {
       value = value.value;
     }
     return '$value';
   }
 }