Incremental parser fix: handle insertion of method parameters.

pkg/analyzer/lib/src/generated/parser.dart

 // Copyright (c) 2014, 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 code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.parser;
 
 import "dart:math" as math;
@@ skipping 1370 matching lines @@
       //return parser.parseTypeName();
       //return parser.parseReturnType();
     } else if (identical(_oldNode, node.name)) {
       if (node.operatorKeyword != null) {
         throw new InsufficientContextException();
       }
       return _parser.parseSimpleIdentifier();
     } else if (identical(_oldNode, node.body)) {
       //return parser.parseFunctionBody();
       throw new InsufficientContextException();
+    } else if (identical(_oldNode, node.parameters)) {
+      // TODO(paulberry): if we want errors to be correct, we'll need to also
+      // call _validateFormalParameterList, and sometimes
+      // _validateModifiersForGetterOrSetterOrMethod.
+      return _parser.parseFormalParameterList();
     }
     return _notAChild(node);
   }
 
   @override
   AstNode visitMethodInvocation(MethodInvocation node) {
     if (identical(_oldNode, node.target)) {
       throw new IncrementalParseException();
     } else if (identical(_oldNode, node.methodName)) {
       return _parser.parseSimpleIdentifier();
@@ skipping 10604 matching lines @@
    * Copy resolution data from one node to another.
    *
    * @param fromNode the node from which resolution information will be copied
    * @param toNode the node to which resolution information will be copied
    */
   static void copyResolutionData(AstNode fromNode, AstNode toNode) {
     ResolutionCopier copier = new ResolutionCopier();
     copier._isEqualNodes(fromNode, toNode);
   }
 }