Allow getters to return Intl messages

pkg/intl/lib/extract_messages.dart

 // Copyright (c) 2013, 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.
 
 /**
  * This is for use in extracting messages from a Dart program
  * using the Intl.message() mechanism and writing them to a file for
  * translation. This provides only the stub of a mechanism, because it
  * doesn't define how the file should be written. It provides an
  * [IntlMessage] class that holds the extracted data and [parseString]
@@ skipping 129 matching lines @@
     var instance = _expectedInstance(node.methodName.name);
     return instance.checkValidity(node, arguments, name, parameters);
   }
 
   /**
    * Record the parameters of the function or method declaration we last
    * encountered before seeing the Intl.message call.
    */
   void visitMethodDeclaration(MethodDeclaration node) {
     parameters = node.parameters;
+    if (parameters == null) parameters = new FormalParameterList();
     name = node.name.name;
     super.visitMethodDeclaration(node);
   }
 
   /**
    * Record the parameters of the function or method declaration we last
    * encountered before seeing the Intl.message call.
    */
   void visitFunctionDeclaration(FunctionDeclaration node) {
     parameters = node.functionExpression.parameters;
+    if (parameters == null) parameters = new FormalParameterList();
     name = node.name.name;
     super.visitFunctionDeclaration(node);
   }
 
   /**
    * Examine method invocations to see if they look like calls to Intl.message.
    * If we've found one, stop recursing. This is important because we can have
    * Intl.message(...Intl.plural...) and we don't want to treat the inner
    * plural as if it was an outermost message.
    */
@@ skipping 294 matching lines @@
    */
   final String message;
 
   /**
    * Creates a new exception with an optional error [message].
    */
   const IntlMessageExtractionException([this.message = ""]);
 
   String toString() => "IntlMessageExtractionException: $message";
 }