Support new import rules.

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 57 matching lines @@
  * 1. what is wrong, 2. why is it wrong, 3. how do I fix it. However, we
  * combine the first two in [template] and the last in [howToFix].
  */
 class MessageKind {
   /// Should describe what is wrong and why.
   final String template;
 
   /// Should describe how to fix the problem. Elided when using --terse option.
   final String howToFix;
 
-  /// Examples will be checked by
-  /// tests/compiler/dart2js/message_kind_test.dart.
-  final List<String> examples;
+  /**
+   *  Examples will be checked by
+   *  tests/compiler/dart2js/message_kind_test.dart.
+   *
+   *  An example is either a String containing the example source code or a Map
+   *  from filenames to source code. In the latter case, the filename for the
+   *  main library code must be 'main.dart'.
+   */
+  final List examples;
 
   const MessageKind(this.template, {this.howToFix, this.examples});
 
   /// Do not use this. It is here for legacy and debugging. It violates item 4
   /// above.
   static const MessageKind GENERIC = const MessageKind('#{text}');
 
   static const DualKind NOT_ASSIGNABLE = const DualKind(
       error: const MessageKind(
           'Error: "#{fromType}" is not assignable to "#{toType}".'),
@@ skipping 90 matching lines @@
   static const MessageKind DUPLICATE_DEFINITION = const MessageKind(
       'Error: Duplicate definition of "#{name}".');
 
   static const MessageKind EXISTING_DEFINITION = const MessageKind(
       'Info: Existing definition of "#{name}".');
 
   static const DualKind DUPLICATE_IMPORT = const DualKind(
       error: const MessageKind('Error: Duplicate import of "#{name}".'),
       warning: const MessageKind('Warning: Duplicate import of "#{name}".'));
 
+  static const MessageKind HIDDEN_IMPORT = const MessageKind(
+      "Warning: '#{name}' from library '#{hiddenUri}' by '#{name}' "
+      "from library '#{hidingUri}'.",
+      howToFix: "Try adding 'hide #{name}' to the import of '#{hiddenUri}'.",
+      examples: const [
+          const {
+'main.dart':
+"""
+import 'dart:async'; // This imports a class Future.
+import 'future.dart';
+
+void main() {}""",
+
+'future.dart':
+"""
+library future;
+
+class Future {}"""},
+
+          const {
+'main.dart':
+"""
+import 'future.dart';
+import 'dart:async'; // This imports a class Future.
+
+void main() {}""",
+
+'future.dart':
+"""
+library future;
+
+class Future {}"""},
+
+          const {
+'main.dart':
+"""
+import 'export.dart';
+import 'dart:async'; // This imports a class Future.
+
+void main() {}""",
+
+'future.dart':
+"""
+library future;
+
+class Future {}""",
+
+'export.dart':
+"""
+library export;
+
+export 'future.dart';"""}]);
+
   static const MessageKind DUPLICATE_EXPORT = const MessageKind(
       'Error: Duplicate export of "#{name}".');
 
   static const DualKind NOT_A_TYPE = const DualKind(
       error: const MessageKind('Error: "#{node}" is not a type.'),
       warning: const MessageKind('Warning: "#{node}" is not a type.'));
 
   static const MessageKind NOT_A_PREFIX = const MessageKind(
       'Error: "#{node}" is not a prefix.');
 
@@ skipping 952 matching lines @@
 
 class CompileTimeConstantError extends Diagnostic {
   CompileTimeConstantError(MessageKind kind, Map arguments, bool terse)
     : super(kind, arguments, terse);
 }
 
 class CompilationError extends Diagnostic {
   CompilationError(MessageKind kind, Map arguments, bool terse)
     : super(kind, arguments, terse);
 }