Support user generated custom native JS classes.

pkg/compiler/lib/src/diagnostics/messages.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.
 
 
 /**
  * The messages in this file should meet the following guide lines:
  *
  * 1. The message should be a complete sentence starting with an uppercase
  * letter, and ending with a period.
@@ skipping 252 matching lines @@
   INVALID_PACKAGE_URI,
   INVALID_PARAMETER,
   INVALID_RECEIVER_IN_INITIALIZER,
   INVALID_SOURCE_FILE_LOCATION,
   INVALID_SYMBOL,
   INVALID_SYNC_MODIFIER,
   INVALID_TYPE_VARIABLE_BOUND,
   INVALID_UNNAMED_CONSTRUCTOR_NAME,
   INVALID_URI,
   INVALID_USE_OF_SUPER,
+  JS_INTEROP_CLASS_CANNOT_EXTEND_DART_CLASS,
+  JS_INTEROP_CLASS_NON_EXTERNAL_MEMBER,
   LIBRARY_NAME_MISMATCH,
   LIBRARY_NOT_FOUND,
   LIBRARY_TAG_MUST_BE_FIRST,
   MAIN_NOT_A_FUNCTION,
   MAIN_WITH_EXTRA_PARAMETER,
   MALFORMED_STRING_LITERAL,
   MEMBER_NOT_FOUND,
   MEMBER_NOT_STATIC,
   MEMBER_USES_CLASS_NAME,
   METHOD_NOT_FOUND,
@@ skipping 1793 matching lines @@
 
       MessageKind.INTERNAL_LIBRARY_FROM:
         const MessageTemplate(MessageKind.INTERNAL_LIBRARY_FROM,
           "Internal library '#{resolvedUri}' is not accessible from "
           "'#{importingUri}'."),
 
       MessageKind.INTERNAL_LIBRARY:
         const MessageTemplate(MessageKind.INTERNAL_LIBRARY,
           "Internal library '#{resolvedUri}' is not accessible."),
 
+      MessageKind.JS_INTEROP_CLASS_CANNOT_EXTEND_DART_CLASS:
+        const MessageTemplate(
+          MessageKind.JS_INTEROP_CLASS_CANNOT_EXTEND_DART_CLASS,
+          "#{cls} cannot extend a normal Dart class as it is annoted with"
+          "@Js.",
+          howToFix: "Add @Js annotation to super class",
+          examples: const [
+          """
+        class Foo { }
+
+        @Js()
+        class Bar extends Foo { }
+        """]),
+
+      MessageKind.JS_INTEROP_CLASS_NON_EXTERNAL_MEMBER:
+        const MessageTemplate(
+          MessageKind.JS_INTEROP_CLASS_NON_EXTERNAL_MEMBER,
+          "Js interop class #{cls} member #{member} is not external.",
+          howToFix: "Mark all interop methods external",
+          examples: const [
+          """
+            @Js
+            class Foo {
+              external bar();
+            }
+            """]),
+
       MessageKind.LIBRARY_NOT_FOUND:
         const MessageTemplate(MessageKind.LIBRARY_NOT_FOUND,
           "Library not found '#{resolvedUri}'."),
 
       MessageKind.UNSUPPORTED_EQ_EQ_EQ:
         const MessageTemplate(MessageKind.UNSUPPORTED_EQ_EQ_EQ,
           "'===' is not an operator. "
           "Did you mean '#{lhs} == #{rhs}' or 'identical(#{lhs}, #{rhs})'?"),
 
       MessageKind.UNSUPPORTED_BANG_EQ_EQ:
@@ skipping 1261 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';
   }
 }