Don't search for 'declaration' of elements, just name is usually enough.

pkg/analysis_server/lib/src/services/refactoring/rename_constructor.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.
 
 library services.src.refactoring.rename_constructor;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/source_range.dart';
@@ skipping 94 matching lines @@
         element.library.source.uri.toString(),
         element.source.uri.toString(),
         MatchKind.DECLARATION,
         sourceRange,
         true,
         true));
   }
 
   Future<Null> _replaceSynthetic() async {
     ClassElement classElement = element.enclosingElement;
-    ClassDeclaration classNode =
-        await astProvider.getResolvedNodeForElement(classElement);
+    AstNode name = await astProvider.getResolvedNameForElement(classElement);
+    ClassDeclaration classNode = name.parent as ClassDeclaration;
     CorrectionUtils utils = new CorrectionUtils(classNode.parent);
     ClassMemberLocation location =
         utils.prepareNewConstructorLocation(classNode);
     doSourceChange_addElementEdit(
         change,
         classElement,
         new SourceEdit(
             location.offset,
             0,
             location.prefix +
                 '${classElement.name}.$newName();' +
                 location.suffix));
   }
 }