1 files changed, 17 insertions, 4 deletions
diff --git a/csharp/ProtocolBuffers/Descriptors/FieldMappingAttribute.cs b/csharp/ProtocolBuffers/Descriptors/FieldMappingAttribute.cs
index 13e8be1e..18f88a31 100644
--- a/csharp/ProtocolBuffers/Descriptors/FieldMappingAttribute.cs
+++ b/csharp/ProtocolBuffers/Descriptors/FieldMappingAttribute.cs
@@ -1,6 +1,19 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.
+// http://code.google.com/p/protobuf/
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+using System;
 
 namespace Google.ProtocolBuffers.Descriptors {
 
@@ -9,7 +22,7 @@ namespace Google.ProtocolBuffers.Descriptors {
   /// this allows each field type to specify the mapped type and wire type.
   /// </summary>
   [AttributeUsage(AttributeTargets.Field)]
-  internal class FieldMappingAttribute : Attribute {
+  internal sealed class FieldMappingAttribute : Attribute {
     internal FieldMappingAttribute(MappedType mappedType, WireFormat.WireType wireType) {
       MappedType = mappedType;
       WireType = wireType;