Handle implicitly hidden exports.

sdk/lib/_internal/compiler/implementation/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 302 matching lines @@
 main() {}""",
 'decl1.dart': "class Class {}",
 'decl2.dart': "class Class {}"}]);
 
   static const MessageKind DUPLICATE_EXPORT_CONT = const MessageKind(
       "This is another export of '#{name}'.");
 
   static const MessageKind DUPLICATE_EXPORT_DECL = const MessageKind(
       "The exported '#{name}' from export #{uriString} is defined here.");
 
+  static const MessageKind HIDDEN_IMPLICIT_EXPORT = const MessageKind(
+      "'#{name}' from library '#{hiddenUri}' is hidden by '#{name}' "
+      "from library '#{hidingUri}'.",
+      howToFix: "Try adding an explicit "
+                "'export \"#{hiddenUri}\" hide #{name}'.",
+      examples: const [
+          const {
+'conflictsWithDartHtml.dart':
+"""
+typedef CanvasElement();
+""",
+
+'reexport.dart':
+r"""
+export 'dart:html';
+export 'conflictsWithDartHtml.dart';
+""",
+
+'main.dart':
+r"""
+import 'reexport.dart';
+
+main() {
+  print(main is CanvasElement);
+}
+"""}]);
+
+
   static const MessageKind NOT_A_TYPE = const MessageKind(
       "'#{node}' is not a type.");
 
   static const MessageKind NOT_A_PREFIX = const MessageKind(
       "'#{node}' is not a prefix.");
 
   static const MessageKind CANNOT_FIND_CONSTRUCTOR = const MessageKind(
       "Cannot find constructor '#{constructorName}'.");
 
   static const MessageKind CYCLIC_CLASS_HIERARCHY = const MessageKind(
@@ skipping 916 matching lines @@
 
   static const MessageKind AMBIGUOUS_REEXPORT = const MessageKind(
       "'#{name}' is (re)exported by multiple libraries.");
 
   static const MessageKind AMBIGUOUS_LOCATION = const MessageKind(
       "'#{name}' is defined here.");
 
   static const MessageKind IMPORTED_HERE = const MessageKind(
       "'#{name}' is imported here.");
 
+  static const MessageKind EXPORTED_HERE = const MessageKind(
+      "'#{name}' from '#{uri}' is exported here.");
+
   static const MessageKind OVERRIDE_EQUALS_NOT_HASH_CODE = const MessageKind(
       "The class '#{class}' overrides 'operator==', "
       "but not 'get hashCode'.");
 
   static const MessageKind PACKAGE_ROOT_NOT_SET = const MessageKind(
       "Cannot resolve '#{uri}'. Package root has not been set.");
 
   static const MessageKind INTERNAL_LIBRARY_FROM = const MessageKind(
       "Internal library '#{resolvedUri}' is not accessible from "
       "'#{importingUri}'.");
@@ skipping 851 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';
   }
 }