Improve NSM handling.

runtime/lib/errors_patch.dart

 // Copyright (c) 2012, 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.
 
 @patch
 class Error {
   @patch
   static String _objectToString(Object object) {
     return Object._toString(object);
   }
@@ skipping 216 matching lines @@
       [List existingArgumentNames = null])
       : _receiver = receiver,
         _memberName = memberName,
         _arguments = positionalArguments,
         _namedArguments = namedArguments,
         _existingArgumentNames = existingArgumentNames,
         _invocation_type = -1;
 
   // This constructor seems to be called with either strings or
   // values read from another NoSuchMethodError.
+  //
+  // NOTE: When making changes to this constructor, please also update
+  // `VmTarget.instantiateNoSuchMethodError` in
+  // `pkg/kernel/lib/target/vm.dart`.
   NoSuchMethodError._withType(
       this._receiver,
       /*String|Symbol*/ memberName,
       this._invocation_type,
       this._arguments,
       Map<dynamic, dynamic> namedArguments,
       [List existingArgumentNames = null])
       : this._memberName =
             (memberName is String) ? new Symbol(memberName) : memberName,
         this._namedArguments = (namedArguments == null)
@@ skipping 172 matching lines @@
 ///
 /// Note: in strong mode, this is a compile-time error and this class becomes
 /// obsolete.
 class _DuplicatedFieldInitializerError extends Error {
   final String _name;
 
   _DuplicatedFieldInitializerError(this._name);
 
   toString() => "Error: field '$_name' is already initialized.";
 }