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 257 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_NOT_SUPPORTED,
   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,
@@ skipping 1835 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,
+          "Js-interop class '#{cls}' cannot extend from the non js-interop "
+          "class '#{superclass}'.",
+          howToFix: "Annotate the superclass with @Js.",
+          examples: const [
+              """
+              import 'package:js/js.dart';
+
+              class Foo { }
+
+              @Js()
+              class Bar extends Foo { }
+
+              main() {
+                new Bar();
+              }
+              """]),
+
+      MessageKind.JS_INTEROP_CLASS_NON_EXTERNAL_MEMBER:
+        const MessageTemplate(
+          MessageKind.JS_INTEROP_CLASS_NON_EXTERNAL_MEMBER,
+          "Member '#{member}' in js-interop class '#{cls}' is not external.",
+          howToFix: "Mark all interop methods external",
+          examples: const [
+              """
+              import 'package:js/js.dart';
+
+              @Js()
+              class Foo {
+                bar() {}
+              }
+
+              main() {
+                new Foo().bar();
+              }
+              """]),
+
       MessageKind.LIBRARY_NOT_FOUND:
         const MessageTemplate(MessageKind.LIBRARY_NOT_FOUND,
           "Library not found '#{resolvedUri}'."),
 
       MessageKind.LIBRARY_NOT_SUPPORTED:
         const MessageTemplate(MessageKind.LIBRARY_NOT_SUPPORTED,
           "Library not supported '#{resolvedUri}'.",
           howToFix: "Try removing the dependency or enabling support using "
                     "the '--categories' option.",
           examples: const [/*
@@ skipping 1318 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';
   }
 }