Update handling of 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 260 matching lines @@
 
 void main() {}""",
 
 'type.dart':
 """
 library type;
 
 class Type {}"""}]);
 
   static const MessageKind DUPLICATE_EXPORT = const MessageKind(
-      "Error: Duplicate export of '#{name}'.");
+      "Error: Duplicate export of '#{name}'.",
+      howToFix: "Trying adding 'hide #{name}' to one of the exports.",
+      examples: const [const {
+'main.dart': """
+export 'decl1.dart';
+export 'decl2.dart';
+
+main() {}""",
+'decl1.dart': "class Class {}",
+'decl2.dart': "class Class {}"}]);
+
+  static const MessageKind DUPLICATE_EXPORT_CONT = const MessageKind(
+      "Info: This is another export of '#{name}'.");
+
+  static const MessageKind DUPLICATE_EXPORT_DECL = const MessageKind(
+      "Info: The exported '#{name}' from export #{uriString} is defined here.");
 
   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.");
 
   static const DualKind CANNOT_FIND_CONSTRUCTOR = const DualKind(
       error: const MessageKind(
@@ skipping 375 matching lines @@
 
   static const MessageKind CANNOT_IMPLEMENT = const MessageKind(
       "Error: '#{type}' cannot be implemented.");
 
   static const MessageKind CANNOT_MIXIN = const MessageKind(
       "Error: The type '#{type}' can't be mixed in.",
       howToFix: "Try removing '#{type}' from the 'with' clause.",
       examples: const ["""
 class C extends Object with String {}
 
-main() => new C();                       
+main() => new C();
 """, """
 typedef C = Object with String;
 
-main() => new C();                       
+main() => new C();
 """]);
 
   static const MessageKind DUPLICATE_EXTENDS_IMPLEMENTS = const MessageKind(
       "Error: '#{type}' can not be both extended and implemented.");
 
   static const MessageKind DUPLICATE_IMPLEMENTS = const MessageKind(
       "Error: '#{type}' must not occur more than once "
       "in the implements clause.");
 
   static const MessageKind ILLEGAL_SUPER_SEND = const MessageKind(
@@ skipping 690 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);
 }