Merge pull request #611 from jskeet/csharp-wrappers

C# wrapper types

24 files changed, 3516 insertions, 129 deletions

diff --git a/BUILD b/BUILD
index 5177e43d..5cfed337 100644
--- a/BUILD
+++ b/BUILD
@@ -162,10 +162,10 @@ cc_library(
         "src/google/protobuf/compiler/cpp/cpp_string_field.cc",
         "src/google/protobuf/compiler/csharp/csharp_enum.cc",
         "src/google/protobuf/compiler/csharp/csharp_enum_field.cc",
-        "src/google/protobuf/compiler/csharp/csharp_extension.cc",
         "src/google/protobuf/compiler/csharp/csharp_field_base.cc",
         "src/google/protobuf/compiler/csharp/csharp_generator.cc",
         "src/google/protobuf/compiler/csharp/csharp_helpers.cc",
+        "src/google/protobuf/compiler/csharp/csharp_map_field.cc",
         "src/google/protobuf/compiler/csharp/csharp_message.cc",
         "src/google/protobuf/compiler/csharp/csharp_message_field.cc",
         "src/google/protobuf/compiler/csharp/csharp_primitive_field.cc",
@@ -174,7 +174,7 @@ cc_library(
         "src/google/protobuf/compiler/csharp/csharp_repeated_primitive_field.cc",
         "src/google/protobuf/compiler/csharp/csharp_source_generator_base.cc",
         "src/google/protobuf/compiler/csharp/csharp_umbrella_class.cc",
-        "src/google/protobuf/compiler/csharp/csharp_writer.cc",
+        "src/google/protobuf/compiler/csharp/csharp_wrapper_field.cc",
         "src/google/protobuf/compiler/java/java_context.cc",
         "src/google/protobuf/compiler/java/java_doc_comment.cc",
         "src/google/protobuf/compiler/java/java_enum.cc",
diff --git a/cmake/libprotoc.cmake b/cmake/libprotoc.cmake
index 8bf0a1f3..f8fa7adb 100644
--- a/cmake/libprotoc.cmake
+++ b/cmake/libprotoc.cmake
@@ -28,6 +28,7 @@ set(libprotoc_files
   ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_repeated_primitive_field.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_source_generator_base.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_umbrella_class.cc
+  ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_wrapper_field.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/java/java_context.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/java/java_doc_comment.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/java/java_enum.cc
diff --git a/csharp/generate_protos.sh b/csharp/generate_protos.sh
index b7f837e1..7978166d 100755
--- a/csharp/generate_protos.sh
+++ b/csharp/generate_protos.sh
@@ -58,7 +58,8 @@ $PROTOC -Isrc --csharp_out=csharp/src/ProtocolBuffers.Test/TestProtos \
     src/google/protobuf/map_unittest_proto3.proto \
     src/google/protobuf/unittest_proto3.proto \
     src/google/protobuf/unittest_import_proto3.proto \
-    src/google/protobuf/unittest_import_public_proto3.proto
+    src/google/protobuf/unittest_import_public_proto3.proto \
+    src/google/protobuf/unittest_well_known_types.proto
 
 
 $PROTOC -Icsharp/protos/extest --csharp_out=csharp/src/ProtocolBuffers.Test/TestProtos \
diff --git a/csharp/src/ProtocolBuffers.Test/ByteStringTest.cs b/csharp/src/ProtocolBuffers.Test/ByteStringTest.cs
index dadd0d33..685e130a 100644
--- a/csharp/src/ProtocolBuffers.Test/ByteStringTest.cs
+++ b/csharp/src/ProtocolBuffers.Test/ByteStringTest.cs
@@ -39,6 +39,34 @@ namespace Google.Protobuf
     public class ByteStringTest

     {

         [Test]

+        public void Equality()

+        {

+            ByteString b1 = ByteString.CopyFrom(1, 2, 3);

+            ByteString b2 = ByteString.CopyFrom(1, 2, 3);

+            ByteString b3 = ByteString.CopyFrom(1, 2, 4);

+            ByteString b4 = ByteString.CopyFrom(1, 2, 3, 4);

+            EqualityTester.AssertEquality(b1, b1);

+            EqualityTester.AssertEquality(b1, b2);

+            EqualityTester.AssertInequality(b1, b3);

+            EqualityTester.AssertInequality(b1, b4);

+            EqualityTester.AssertInequality(b1, null);

+#pragma warning disable 1718 // Deliberately calling ==(b1, b1) and !=(b1, b1)

+            Assert.IsTrue(b1 == b1);

+            Assert.IsTrue(b1 == b2);

+            Assert.IsFalse(b1 == b3);

+            Assert.IsFalse(b1 == b4);

+            Assert.IsFalse(b1 == null);

+            Assert.IsTrue((ByteString) null == null);

+            Assert.IsFalse(b1 != b1);

+            Assert.IsFalse(b1 != b2);

+#pragma warning disable 1718

+            Assert.IsTrue(b1 != b3);

+            Assert.IsTrue(b1 != b4);

+            Assert.IsTrue(b1 != null);

+            Assert.IsFalse((ByteString) null != null);

+        }

+

+        [Test]

         public void EmptyByteStringHasZeroSize()

         {

             Assert.AreEqual(0, ByteString.Empty.Length);

diff --git a/csharp/src/ProtocolBuffers.Test/Collections/MapFieldTest.cs b/csharp/src/ProtocolBuffers.Test/Collections/MapFieldTest.cs
index d43bed3e..46d3bd9a 100644
--- a/csharp/src/ProtocolBuffers.Test/Collections/MapFieldTest.cs
+++ b/csharp/src/ProtocolBuffers.Test/Collections/MapFieldTest.cs
@@ -103,32 +103,35 @@ namespace Google.Protobuf.Collections
         }
 
         [Test]
-        public void Add_ForbidsNullKeys()
+        public void NullValues()
         {
-            var map = new MapField<string, ForeignMessage>();
-            Assert.Throws<ArgumentNullException>(() => map.Add(null, new ForeignMessage()));
+            TestNullValues<int?>(0);
+            TestNullValues("");
+            TestNullValues(new TestAllTypes());
         }
 
-        [Test]
-        public void Add_AcceptsNullMessageValues()
+        private void TestNullValues<T>(T nonNullValue)
         {
-            var map = new MapField<string, ForeignMessage>();
-            map.Add("missing", null);
-            Assert.IsNull(map["missing"]);
-        }
+            var map = new MapField<int, T>(false);
+            var nullValue = (T) (object) null;
+            Assert.Throws<ArgumentNullException>(() => map.Add(0, nullValue));
+            Assert.Throws<ArgumentNullException>(() => map[0] = nullValue);
+            map.Add(1, nonNullValue);
+            map[1] = nonNullValue;
 
-        [Test]
-        public void Add_ForbidsNullStringValues()
-        {
-            var map = new MapField<string, string>();
-            Assert.Throws<ArgumentNullException>(() => map.Add("missing", null));
+            // Doesn't throw...
+            map = new MapField<int, T>(true);
+            map.Add(0, nullValue);
+            map[0] = nullValue;
+            map.Add(1, nonNullValue);
+            map[1] = nonNullValue;
         }
 
         [Test]
-        public void Add_ForbidsNullByteStringValues()
+        public void Add_ForbidsNullKeys()
         {
-            var map = new MapField<string, ByteString>();
-            Assert.Throws<ArgumentNullException>(() => map.Add("missing", null));
+            var map = new MapField<string, ForeignMessage>();
+            Assert.Throws<ArgumentNullException>(() => map.Add(null, new ForeignMessage()));
         }
 
         [Test]
@@ -137,29 +140,7 @@ namespace Google.Protobuf.Collections
             var map = new MapField<string, ForeignMessage>();
             Assert.Throws<ArgumentNullException>(() => map[null] = new ForeignMessage());
         }
-
-        [Test]
-        public void Indexer_AcceptsNullMessageValues()
-        {
-            var map = new MapField<string, ForeignMessage>();
-            map["missing"] = null;
-            Assert.IsNull(map["missing"]);
-        }
-
-        [Test]
-        public void Indexer_ForbidsNullStringValues()
-        {
-            var map = new MapField<string, string>();
-            Assert.Throws<ArgumentNullException>(() => map["missing"] = null);
-        }
-
-        [Test]
-        public void Indexer_ForbidsNullByteStringValues()
-        {
-            var map = new MapField<string, ByteString>();
-            Assert.Throws<ArgumentNullException>(() => map["missing"] = null);
-        }
-
+        
         [Test]
         public void AddPreservesInsertionOrder()
         {
@@ -528,6 +509,30 @@ namespace Google.Protobuf.Collections
             Assert.Throws<NotSupportedException>(() => dictionary["a"] = "c");
         }
 
+        [Test]
+        public void AllowNullValues_Property()
+        {
+            // Non-message reference type values are non-nullable by default, but can be overridden
+            Assert.IsFalse(new MapField<int, string>().AllowsNullValues);
+            Assert.IsFalse(new MapField<int, string>(false).AllowsNullValues);
+            Assert.IsTrue(new MapField<int, string>(true).AllowsNullValues);
+
+            // Non-nullable value type values are never nullable
+            Assert.IsFalse(new MapField<int, int>().AllowsNullValues);
+            Assert.IsFalse(new MapField<int, int>(false).AllowsNullValues);
+            Assert.Throws<ArgumentException>(() => new MapField<int, int>(true));
+
+            // Message type values are nullable by default, but can be overridden
+            Assert.IsTrue(new MapField<int, TestAllTypes>().AllowsNullValues);
+            Assert.IsFalse(new MapField<int, TestAllTypes>(false).AllowsNullValues);
+            Assert.IsTrue(new MapField<int, TestAllTypes>(true).AllowsNullValues);
+
+            // Nullable value type values are nullable by default, but can be overridden
+            Assert.IsTrue(new MapField<int, int?>().AllowsNullValues);
+            Assert.IsFalse(new MapField<int, int?>(false).AllowsNullValues);
+            Assert.IsTrue(new MapField<int, int?>(true).AllowsNullValues);
+        }
+
         private static KeyValuePair<TKey, TValue> NewKeyValuePair<TKey, TValue>(TKey key, TValue value)
         {
             return new KeyValuePair<TKey, TValue>(key, value);
diff --git a/csharp/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj b/csharp/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
index 45c75bae..a425ad84 100644
--- a/csharp/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
+++ b/csharp/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
@@ -93,6 +93,8 @@
     <Compile Include="IssuesTest.cs" />

     <Compile Include="Properties\AssemblyInfo.cs" />

     <Compile Include="TestCornerCases.cs" />

+    <Compile Include="TestProtos\UnittestWellKnownTypes.cs" />

+    <Compile Include="WellKnownTypes\WrappersTest.cs" />

   </ItemGroup>

   <ItemGroup>

     <ProjectReference Include="..\ProtocolBuffers\ProtocolBuffers.csproj">

diff --git a/csharp/src/ProtocolBuffers.Test/TestProtos/UnittestWellKnownTypes.cs b/csharp/src/ProtocolBuffers.Test/TestProtos/UnittestWellKnownTypes.cs
new file mode 100644
index 00000000..af7d83ba
--- /dev/null
+++ b/csharp/src/ProtocolBuffers.Test/TestProtos/UnittestWellKnownTypes.cs
@@ -0,0 +1,2453 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: google/protobuf/unittest_well_known_types.proto
+#pragma warning disable 1591, 0612, 3021
+#region Designer generated code
+
+using pb = global::Google.Protobuf;
+using pbc = global::Google.Protobuf.Collections;
+using pbr = global::Google.Protobuf.Reflection;
+using scg = global::System.Collections.Generic;
+namespace Google.Protobuf.TestProtos {
+
+  [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+  public static partial class UnittestWellKnownTypes {
+
+    #region Static variables
+    internal static pbr::FieldAccessorTable internal__static_protobuf_unittest_TestWellKnownTypes__FieldAccessorTable;
+    internal static pbr::FieldAccessorTable internal__static_protobuf_unittest_RepeatedWellKnownTypes__FieldAccessorTable;
+    internal static pbr::FieldAccessorTable internal__static_protobuf_unittest_OneofWellKnownTypes__FieldAccessorTable;
+    internal static pbr::FieldAccessorTable internal__static_protobuf_unittest_MapWellKnownTypes__FieldAccessorTable;
+    #endregion
+    #region Descriptor
+    public static pbr::FileDescriptor Descriptor {
+      get { return descriptor; }
+    }
+    private static pbr::FileDescriptor descriptor;
+
+    static UnittestWellKnownTypes() {
+      byte[] descriptorData = global::System.Convert.FromBase64String(
+          string.Concat(
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+          "dFByb3Rvc2IGcHJvdG8z"));
+      descriptor = pbr::FileDescriptor.InternalBuildGeneratedFileFrom(descriptorData,
+          new pbr::FileDescriptor[] {
+          global::Google.Protobuf.WellKnownTypes.Proto.Any.Descriptor, 
+          global::Google.Protobuf.WellKnownTypes.Proto.Api.Descriptor, 
+          global::Google.Protobuf.WellKnownTypes.Proto.Duration.Descriptor, 
+          global::Google.Protobuf.WellKnownTypes.Proto.Empty.Descriptor, 
+          global::Google.Protobuf.WellKnownTypes.Proto.FieldMask.Descriptor, 
+          global::Google.Protobuf.WellKnownTypes.Proto.SourceContext.Descriptor, 
+          global::Google.Protobuf.WellKnownTypes.Proto.Struct.Descriptor, 
+          global::Google.Protobuf.WellKnownTypes.Proto.Timestamp.Descriptor, 
+          global::Google.Protobuf.WellKnownTypes.Proto.Type.Descriptor, 
+          global::Google.Protobuf.WellKnownTypes.Wrappers.Descriptor, 
+          });
+      internal__static_protobuf_unittest_TestWellKnownTypes__FieldAccessorTable = 
+          new pbr::FieldAccessorTable(typeof(global::Google.Protobuf.TestProtos.TestWellKnownTypes), descriptor.MessageTypes[0],
+              new string[] { "AnyField", "ApiField", "DurationField", "EmptyField", "FieldMaskField", "SourceContextField", "StructField", "TimestampField", "TypeField", "DoubleField", "FloatField", "Int64Field", "Uint64Field", "Int32Field", "Uint32Field", "BoolField", "StringField", "BytesField", }, new string[] { });
+      internal__static_protobuf_unittest_RepeatedWellKnownTypes__FieldAccessorTable = 
+          new pbr::FieldAccessorTable(typeof(global::Google.Protobuf.TestProtos.RepeatedWellKnownTypes), descriptor.MessageTypes[1],
+              new string[] { "AnyField", "ApiField", "DurationField", "EmptyField", "FieldMaskField", "SourceContextField", "StructField", "TimestampField", "TypeField", "DoubleField", "FloatField", "Int64Field", "Uint64Field", "Int32Field", "Uint32Field", "BoolField", "StringField", "BytesField", }, new string[] { });
+      internal__static_protobuf_unittest_OneofWellKnownTypes__FieldAccessorTable = 
+          new pbr::FieldAccessorTable(typeof(global::Google.Protobuf.TestProtos.OneofWellKnownTypes), descriptor.MessageTypes[2],
+              new string[] { "AnyField", "ApiField", "DurationField", "EmptyField", "FieldMaskField", "SourceContextField", "StructField", "TimestampField", "TypeField", "DoubleField", "FloatField", "Int64Field", "Uint64Field", "Int32Field", "Uint32Field", "BoolField", "StringField", "BytesField", }, new string[] { "OneofField", });
+      internal__static_protobuf_unittest_MapWellKnownTypes__FieldAccessorTable = 
+          new pbr::FieldAccessorTable(typeof(global::Google.Protobuf.TestProtos.MapWellKnownTypes), descriptor.MessageTypes[3],
+              new string[] { "AnyField", "ApiField", "DurationField", "EmptyField", "FieldMaskField", "SourceContextField", "StructField", "TimestampField", "TypeField", "DoubleField", "FloatField", "Int64Field", "Uint64Field", "Int32Field", "Uint32Field", "BoolField", "StringField", "BytesField", }, new string[] { });
+    }
+    #endregion
+
+  }
+  #region Messages
+  [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+  public sealed partial class TestWellKnownTypes : pb::IMessage<TestWellKnownTypes> {
+    private static readonly pb::MessageParser<TestWellKnownTypes> _parser = new pb::MessageParser<TestWellKnownTypes>(() => new TestWellKnownTypes());
+    public static pb::MessageParser<TestWellKnownTypes> Parser { get { return _parser; } }
+
+    private static readonly string[] _fieldNames = new string[] { "any_field", "api_field", "bool_field", "bytes_field", "double_field", "duration_field", "empty_field", "field_mask_field", "float_field", "int32_field", "int64_field", "source_context_field", "string_field", "struct_field", "timestamp_field", "type_field", "uint32_field", "uint64_field" };
+    private static readonly uint[] _fieldTags = new uint[] { 10, 18, 130, 146, 82, 26, 34, 42, 90, 114, 98, 50, 138, 58, 66, 74, 122, 106 };
+    public static pbr::MessageDescriptor Descriptor {
+      get { return global::Google.Protobuf.TestProtos.UnittestWellKnownTypes.Descriptor.MessageTypes[0]; }
+    }
+
+    pbr::FieldAccessorTable pb::IReflectedMessage.Fields {
+      get { return global::Google.Protobuf.TestProtos.UnittestWellKnownTypes.internal__static_protobuf_unittest_TestWellKnownTypes__FieldAccessorTable; }
+    }
+
+    private bool _frozen = false;
+    public bool IsFrozen { get { return _frozen; } }
+
+    public TestWellKnownTypes() {
+      OnConstruction();
+    }
+
+    partial void OnConstruction();
+
+    public TestWellKnownTypes(TestWellKnownTypes other) : this() {
+      AnyField = other.anyField_ != null ? other.AnyField.Clone() : null;
+      ApiField = other.apiField_ != null ? other.ApiField.Clone() : null;
+      DurationField = other.durationField_ != null ? other.DurationField.Clone() : null;
+      EmptyField = other.emptyField_ != null ? other.EmptyField.Clone() : null;
+      FieldMaskField = other.fieldMaskField_ != null ? other.FieldMaskField.Clone() : null;
+      SourceContextField = other.sourceContextField_ != null ? other.SourceContextField.Clone() : null;
+      StructField = other.structField_ != null ? other.StructField.Clone() : null;
+      TimestampField = other.timestampField_ != null ? other.TimestampField.Clone() : null;
+      TypeField = other.typeField_ != null ? other.TypeField.Clone() : null;
+      DoubleField = other.DoubleField;
+      FloatField = other.FloatField;
+      Int64Field = other.Int64Field;
+      Uint64Field = other.Uint64Field;
+      Int32Field = other.Int32Field;
+      Uint32Field = other.Uint32Field;
+      BoolField = other.BoolField;
+      StringField = other.StringField;
+      BytesField = other.BytesField;
+    }
+
+    public TestWellKnownTypes Clone() {
+      return new TestWellKnownTypes(this);
+    }
+
+    public void Freeze() {
+      if (IsFrozen) {
+        return;
+      }
+      _frozen = true;
+      if (anyField_ != null) AnyField.Freeze();
+      if (apiField_ != null) ApiField.Freeze();
+      if (durationField_ != null) DurationField.Freeze();
+      if (emptyField_ != null) EmptyField.Freeze();
+      if (fieldMaskField_ != null) FieldMaskField.Freeze();
+      if (sourceContextField_ != null) SourceContextField.Freeze();
+      if (structField_ != null) StructField.Freeze();
+      if (timestampField_ != null) TimestampField.Freeze();
+      if (typeField_ != null) TypeField.Freeze();
+    }
+
+    public const int AnyFieldFieldNumber = 1;
+    private global::Google.Protobuf.WellKnownTypes.Any anyField_;
+    public global::Google.Protobuf.WellKnownTypes.Any AnyField {
+      get { return anyField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        anyField_ = value;
+      }
+    }
+
+    public const int ApiFieldFieldNumber = 2;
+    private global::Google.Protobuf.WellKnownTypes.Api apiField_;
+    public global::Google.Protobuf.WellKnownTypes.Api ApiField {
+      get { return apiField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        apiField_ = value;
+      }
+    }
+
+    public const int DurationFieldFieldNumber = 3;
+    private global::Google.Protobuf.WellKnownTypes.Duration durationField_;
+    public global::Google.Protobuf.WellKnownTypes.Duration DurationField {
+      get { return durationField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        durationField_ = value;
+      }
+    }
+
+    public const int EmptyFieldFieldNumber = 4;
+    private global::Google.Protobuf.WellKnownTypes.Empty emptyField_;
+    public global::Google.Protobuf.WellKnownTypes.Empty EmptyField {
+      get { return emptyField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        emptyField_ = value;
+      }
+    }
+
+    public const int FieldMaskFieldFieldNumber = 5;
+    private global::Google.Protobuf.WellKnownTypes.FieldMask fieldMaskField_;
+    public global::Google.Protobuf.WellKnownTypes.FieldMask FieldMaskField {
+      get { return fieldMaskField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        fieldMaskField_ = value;
+      }
+    }
+
+    public const int SourceContextFieldFieldNumber = 6;
+    private global::Google.Protobuf.WellKnownTypes.SourceContext sourceContextField_;
+    public global::Google.Protobuf.WellKnownTypes.SourceContext SourceContextField {
+      get { return sourceContextField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        sourceContextField_ = value;
+      }
+    }
+
+    public const int StructFieldFieldNumber = 7;
+    private global::Google.Protobuf.WellKnownTypes.Struct structField_;
+    public global::Google.Protobuf.WellKnownTypes.Struct StructField {
+      get { return structField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        structField_ = value;
+      }
+    }
+
+    public const int TimestampFieldFieldNumber = 8;
+    private global::Google.Protobuf.WellKnownTypes.Timestamp timestampField_;
+    public global::Google.Protobuf.WellKnownTypes.Timestamp TimestampField {
+      get { return timestampField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        timestampField_ = value;
+      }
+    }
+
+    public const int TypeFieldFieldNumber = 9;
+    private global::Google.Protobuf.WellKnownTypes.Type typeField_;
+    public global::Google.Protobuf.WellKnownTypes.Type TypeField {
+      get { return typeField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        typeField_ = value;
+      }
+    }
+
+    public const int DoubleFieldFieldNumber = 10;
+    private static readonly pb::FieldCodec<double?> _single_doubleField_codec = pb::FieldCodec.ForStructWrapper<double>(82);
+    private double? doubleField_;
+    public double? DoubleField {
+      get { return doubleField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        doubleField_ = value;
+      }
+    }
+
+    public const int FloatFieldFieldNumber = 11;
+    private static readonly pb::FieldCodec<float?> _single_floatField_codec = pb::FieldCodec.ForStructWrapper<float>(90);
+    private float? floatField_;
+    public float? FloatField {
+      get { return floatField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        floatField_ = value;
+      }
+    }
+
+    public const int Int64FieldFieldNumber = 12;
+    private static readonly pb::FieldCodec<long?> _single_int64Field_codec = pb::FieldCodec.ForStructWrapper<long>(98);
+    private long? int64Field_;
+    public long? Int64Field {
+      get { return int64Field_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        int64Field_ = value;
+      }
+    }
+
+    public const int Uint64FieldFieldNumber = 13;
+    private static readonly pb::FieldCodec<ulong?> _single_uint64Field_codec = pb::FieldCodec.ForStructWrapper<ulong>(106);
+    private ulong? uint64Field_;
+    public ulong? Uint64Field {
+      get { return uint64Field_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        uint64Field_ = value;
+      }
+    }
+
+    public const int Int32FieldFieldNumber = 14;
+    private static readonly pb::FieldCodec<int?> _single_int32Field_codec = pb::FieldCodec.ForStructWrapper<int>(114);
+    private int? int32Field_;
+    public int? Int32Field {
+      get { return int32Field_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        int32Field_ = value;
+      }
+    }
+
+    public const int Uint32FieldFieldNumber = 15;
+    private static readonly pb::FieldCodec<uint?> _single_uint32Field_codec = pb::FieldCodec.ForStructWrapper<uint>(122);
+    private uint? uint32Field_;
+    public uint? Uint32Field {
+      get { return uint32Field_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        uint32Field_ = value;
+      }
+    }
+
+    public const int BoolFieldFieldNumber = 16;
+    private static readonly pb::FieldCodec<bool?> _single_boolField_codec = pb::FieldCodec.ForStructWrapper<bool>(130);
+    private bool? boolField_;
+    public bool? BoolField {
+      get { return boolField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        boolField_ = value;
+      }
+    }
+
+    public const int StringFieldFieldNumber = 17;
+    private static readonly pb::FieldCodec<string> _single_stringField_codec = pb::FieldCodec.ForClassWrapper<string>(138);
+    private string stringField_;
+    public string StringField {
+      get { return stringField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        stringField_ = value;
+      }
+    }
+
+    public const int BytesFieldFieldNumber = 18;
+    private static readonly pb::FieldCodec<pb::ByteString> _single_bytesField_codec = pb::FieldCodec.ForClassWrapper<pb::ByteString>(146);
+    private pb::ByteString bytesField_;
+    public pb::ByteString BytesField {
+      get { return bytesField_; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        bytesField_ = value;
+      }
+    }
+
+    public override bool Equals(object other) {
+      return Equals(other as TestWellKnownTypes);
+    }
+
+    public bool Equals(TestWellKnownTypes other) {
+      if (ReferenceEquals(other, null)) {
+        return false;
+      }
+      if (ReferenceEquals(other, this)) {
+        return true;
+      }
+      if (!object.Equals(AnyField, other.AnyField)) return false;
+      if (!object.Equals(ApiField, other.ApiField)) return false;
+      if (!object.Equals(DurationField, other.DurationField)) return false;
+      if (!object.Equals(EmptyField, other.EmptyField)) return false;
+      if (!object.Equals(FieldMaskField, other.FieldMaskField)) return false;
+      if (!object.Equals(SourceContextField, other.SourceContextField)) return false;
+      if (!object.Equals(StructField, other.StructField)) return false;
+      if (!object.Equals(TimestampField, other.TimestampField)) return false;
+      if (!object.Equals(TypeField, other.TypeField)) return false;
+      if (DoubleField != other.DoubleField) return false;
+      if (FloatField != other.FloatField) return false;
+      if (Int64Field != other.Int64Field) return false;
+      if (Uint64Field != other.Uint64Field) return false;
+      if (Int32Field != other.Int32Field) return false;
+      if (Uint32Field != other.Uint32Field) return false;
+      if (BoolField != other.BoolField) return false;
+      if (StringField != other.StringField) return false;
+      if (BytesField != other.BytesField) return false;
+      return true;
+    }
+
+    public override int GetHashCode() {
+      int hash = 1;
+      if (anyField_ != null) hash ^= AnyField.GetHashCode();
+      if (apiField_ != null) hash ^= ApiField.GetHashCode();
+      if (durationField_ != null) hash ^= DurationField.GetHashCode();
+      if (emptyField_ != null) hash ^= EmptyField.GetHashCode();
+      if (fieldMaskField_ != null) hash ^= FieldMaskField.GetHashCode();
+      if (sourceContextField_ != null) hash ^= SourceContextField.GetHashCode();
+      if (structField_ != null) hash ^= StructField.GetHashCode();
+      if (timestampField_ != null) hash ^= TimestampField.GetHashCode();
+      if (typeField_ != null) hash ^= TypeField.GetHashCode();
+      if (doubleField_ != null) hash ^= DoubleField.GetHashCode();
+      if (floatField_ != null) hash ^= FloatField.GetHashCode();
+      if (int64Field_ != null) hash ^= Int64Field.GetHashCode();
+      if (uint64Field_ != null) hash ^= Uint64Field.GetHashCode();
+      if (int32Field_ != null) hash ^= Int32Field.GetHashCode();
+      if (uint32Field_ != null) hash ^= Uint32Field.GetHashCode();
+      if (boolField_ != null) hash ^= BoolField.GetHashCode();
+      if (stringField_ != null) hash ^= StringField.GetHashCode();
+      if (bytesField_ != null) hash ^= BytesField.GetHashCode();
+      return hash;
+    }
+
+    public override string ToString() {
+      return pb::JsonFormatter.Default.Format(this);
+    }
+
+    public void WriteTo(pb::CodedOutputStream output) {
+      if (anyField_ != null) {
+        output.WriteRawTag(10);
+        output.WriteMessage(AnyField);
+      }
+      if (apiField_ != null) {
+        output.WriteRawTag(18);
+        output.WriteMessage(ApiField);
+      }
+      if (durationField_ != null) {
+        output.WriteRawTag(26);
+        output.WriteMessage(DurationField);
+      }
+      if (emptyField_ != null) {
+        output.WriteRawTag(34);
+        output.WriteMessage(EmptyField);
+      }
+      if (fieldMaskField_ != null) {
+        output.WriteRawTag(42);
+        output.WriteMessage(FieldMaskField);
+      }
+      if (sourceContextField_ != null) {
+        output.WriteRawTag(50);
+        output.WriteMessage(SourceContextField);
+      }
+      if (structField_ != null) {
+        output.WriteRawTag(58);
+        output.WriteMessage(StructField);
+      }
+      if (timestampField_ != null) {
+        output.WriteRawTag(66);
+        output.WriteMessage(TimestampField);
+      }
+      if (typeField_ != null) {
+        output.WriteRawTag(74);
+        output.WriteMessage(TypeField);
+      }
+      if (doubleField_ != null) {
+        _single_doubleField_codec.WriteTagAndValue(output, DoubleField);
+      }
+      if (floatField_ != null) {
+        _single_floatField_codec.WriteTagAndValue(output, FloatField);
+      }
+      if (int64Field_ != null) {
+        _single_int64Field_codec.WriteTagAndValue(output, Int64Field);
+      }
+      if (uint64Field_ != null) {
+        _single_uint64Field_codec.WriteTagAndValue(output, Uint64Field);
+      }
+      if (int32Field_ != null) {
+        _single_int32Field_codec.WriteTagAndValue(output, Int32Field);
+      }
+      if (uint32Field_ != null) {
+        _single_uint32Field_codec.WriteTagAndValue(output, Uint32Field);
+      }
+      if (boolField_ != null) {
+        _single_boolField_codec.WriteTagAndValue(output, BoolField);
+      }
+      if (stringField_ != null) {
+        _single_stringField_codec.WriteTagAndValue(output, StringField);
+      }
+      if (bytesField_ != null) {
+        _single_bytesField_codec.WriteTagAndValue(output, BytesField);
+      }
+    }
+
+    public int CalculateSize() {
+      int size = 0;
+      if (anyField_ != null) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(AnyField);
+      }
+      if (apiField_ != null) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(ApiField);
+      }
+      if (durationField_ != null) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(DurationField);
+      }
+      if (emptyField_ != null) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(EmptyField);
+      }
+      if (fieldMaskField_ != null) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(FieldMaskField);
+      }
+      if (sourceContextField_ != null) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(SourceContextField);
+      }
+      if (structField_ != null) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(StructField);
+      }
+      if (timestampField_ != null) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(TimestampField);
+      }
+      if (typeField_ != null) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(TypeField);
+      }
+      if (doubleField_ != null) {
+        size += _single_doubleField_codec.CalculateSizeWithTag(DoubleField);
+      }
+      if (floatField_ != null) {
+        size += _single_floatField_codec.CalculateSizeWithTag(FloatField);
+      }
+      if (int64Field_ != null) {
+        size += _single_int64Field_codec.CalculateSizeWithTag(Int64Field);
+      }
+      if (uint64Field_ != null) {
+        size += _single_uint64Field_codec.CalculateSizeWithTag(Uint64Field);
+      }
+      if (int32Field_ != null) {
+        size += _single_int32Field_codec.CalculateSizeWithTag(Int32Field);
+      }
+      if (uint32Field_ != null) {
+        size += _single_uint32Field_codec.CalculateSizeWithTag(Uint32Field);
+      }
+      if (boolField_ != null) {
+        size += _single_boolField_codec.CalculateSizeWithTag(BoolField);
+      }
+      if (stringField_ != null) {
+        size += _single_stringField_codec.CalculateSizeWithTag(StringField);
+      }
+      if (bytesField_ != null) {
+        size += _single_bytesField_codec.CalculateSizeWithTag(BytesField);
+      }
+      return size;
+    }
+
+    public void MergeFrom(TestWellKnownTypes other) {
+      if (other == null) {
+        return;
+      }
+      if (other.anyField_ != null) {
+        if (anyField_ == null) {
+          anyField_ = new global::Google.Protobuf.WellKnownTypes.Any();
+        }
+        AnyField.MergeFrom(other.AnyField);
+      }
+      if (other.apiField_ != null) {
+        if (apiField_ == null) {
+          apiField_ = new global::Google.Protobuf.WellKnownTypes.Api();
+        }
+        ApiField.MergeFrom(other.ApiField);
+      }
+      if (other.durationField_ != null) {
+        if (durationField_ == null) {
+          durationField_ = new global::Google.Protobuf.WellKnownTypes.Duration();
+        }
+        DurationField.MergeFrom(other.DurationField);
+      }
+      if (other.emptyField_ != null) {
+        if (emptyField_ == null) {
+          emptyField_ = new global::Google.Protobuf.WellKnownTypes.Empty();
+        }
+        EmptyField.MergeFrom(other.EmptyField);
+      }
+      if (other.fieldMaskField_ != null) {
+        if (fieldMaskField_ == null) {
+          fieldMaskField_ = new global::Google.Protobuf.WellKnownTypes.FieldMask();
+        }
+        FieldMaskField.MergeFrom(other.FieldMaskField);
+      }
+      if (other.sourceContextField_ != null) {
+        if (sourceContextField_ == null) {
+          sourceContextField_ = new global::Google.Protobuf.WellKnownTypes.SourceContext();
+        }
+        SourceContextField.MergeFrom(other.SourceContextField);
+      }
+      if (other.structField_ != null) {
+        if (structField_ == null) {
+          structField_ = new global::Google.Protobuf.WellKnownTypes.Struct();
+        }
+        StructField.MergeFrom(other.StructField);
+      }
+      if (other.timestampField_ != null) {
+        if (timestampField_ == null) {
+          timestampField_ = new global::Google.Protobuf.WellKnownTypes.Timestamp();
+        }
+        TimestampField.MergeFrom(other.TimestampField);
+      }
+      if (other.typeField_ != null) {
+        if (typeField_ == null) {
+          typeField_ = new global::Google.Protobuf.WellKnownTypes.Type();
+        }
+        TypeField.MergeFrom(other.TypeField);
+      }
+      if (other.doubleField_ != null) {
+        if (doubleField_ == null || other.DoubleField != 0D) {
+          DoubleField = other.DoubleField;
+        }
+      }
+      if (other.floatField_ != null) {
+        if (floatField_ == null || other.FloatField != 0F) {
+          FloatField = other.FloatField;
+        }
+      }
+      if (other.int64Field_ != null) {
+        if (int64Field_ == null || other.Int64Field != 0L) {
+          Int64Field = other.Int64Field;
+        }
+      }
+      if (other.uint64Field_ != null) {
+        if (uint64Field_ == null || other.Uint64Field != 0UL) {
+          Uint64Field = other.Uint64Field;
+        }
+      }
+      if (other.int32Field_ != null) {
+        if (int32Field_ == null || other.Int32Field != 0) {
+          Int32Field = other.Int32Field;
+        }
+      }
+      if (other.uint32Field_ != null) {
+        if (uint32Field_ == null || other.Uint32Field != 0) {
+          Uint32Field = other.Uint32Field;
+        }
+      }
+      if (other.boolField_ != null) {
+        if (boolField_ == null || other.BoolField != false) {
+          BoolField = other.BoolField;
+        }
+      }
+      if (other.stringField_ != null) {
+        if (stringField_ == null || other.StringField != "") {
+          StringField = other.StringField;
+        }
+      }
+      if (other.bytesField_ != null) {
+        if (bytesField_ == null || other.BytesField != pb::ByteString.Empty) {
+          BytesField = other.BytesField;
+        }
+      }
+    }
+
+    public void MergeFrom(pb::CodedInputStream input) {
+      uint tag;
+      while (input.ReadTag(out tag)) {
+        switch(tag) {
+          case 0:
+            throw pb::InvalidProtocolBufferException.InvalidTag();
+          default:
+            if (pb::WireFormat.IsEndGroupTag(tag)) {
+              return;
+            }
+            break;
+          case 10: {
+            if (anyField_ == null) {
+              anyField_ = new global::Google.Protobuf.WellKnownTypes.Any();
+            }
+            input.ReadMessage(anyField_);
+            break;
+          }
+          case 18: {
+            if (apiField_ == null) {
+              apiField_ = new global::Google.Protobuf.WellKnownTypes.Api();
+            }
+            input.ReadMessage(apiField_);
+            break;
+          }
+          case 26: {
+            if (durationField_ == null) {
+              durationField_ = new global::Google.Protobuf.WellKnownTypes.Duration();
+            }
+            input.ReadMessage(durationField_);
+            break;
+          }
+          case 34: {
+            if (emptyField_ == null) {
+              emptyField_ = new global::Google.Protobuf.WellKnownTypes.Empty();
+            }
+            input.ReadMessage(emptyField_);
+            break;
+          }
+          case 42: {
+            if (fieldMaskField_ == null) {
+              fieldMaskField_ = new global::Google.Protobuf.WellKnownTypes.FieldMask();
+            }
+            input.ReadMessage(fieldMaskField_);
+            break;
+          }
+          case 50: {
+            if (sourceContextField_ == null) {
+              sourceContextField_ = new global::Google.Protobuf.WellKnownTypes.SourceContext();
+            }
+            input.ReadMessage(sourceContextField_);
+            break;
+          }
+          case 58: {
+            if (structField_ == null) {
+              structField_ = new global::Google.Protobuf.WellKnownTypes.Struct();
+            }
+            input.ReadMessage(structField_);
+            break;
+          }
+          case 66: {
+            if (timestampField_ == null) {
+              timestampField_ = new global::Google.Protobuf.WellKnownTypes.Timestamp();
+            }
+            input.ReadMessage(timestampField_);
+            break;
+          }
+          case 74: {
+            if (typeField_ == null) {
+              typeField_ = new global::Google.Protobuf.WellKnownTypes.Type();
+            }
+            input.ReadMessage(typeField_);
+            break;
+          }
+          case 82: {
+            double? value = _single_doubleField_codec.Read(input);
+            if (doubleField_ == null || value != 0D) {
+              DoubleField = value;
+            }
+            break;
+          }
+          case 90: {
+            float? value = _single_floatField_codec.Read(input);
+            if (floatField_ == null || value != 0F) {
+              FloatField = value;
+            }
+            break;
+          }
+          case 98: {
+            long? value = _single_int64Field_codec.Read(input);
+            if (int64Field_ == null || value != 0L) {
+              Int64Field = value;
+            }
+            break;
+          }
+          case 106: {
+            ulong? value = _single_uint64Field_codec.Read(input);
+            if (uint64Field_ == null || value != 0UL) {
+              Uint64Field = value;
+            }
+            break;
+          }
+          case 114: {
+            int? value = _single_int32Field_codec.Read(input);
+            if (int32Field_ == null || value != 0) {
+              Int32Field = value;
+            }
+            break;
+          }
+          case 122: {
+            uint? value = _single_uint32Field_codec.Read(input);
+            if (uint32Field_ == null || value != 0) {
+              Uint32Field = value;
+            }
+            break;
+          }
+          case 130: {
+            bool? value = _single_boolField_codec.Read(input);
+            if (boolField_ == null || value != false) {
+              BoolField = value;
+            }
+            break;
+          }
+          case 138: {
+            string value = _single_stringField_codec.Read(input);
+            if (stringField_ == null || value != "") {
+              StringField = value;
+            }
+            break;
+          }
+          case 146: {
+            pb::ByteString value = _single_bytesField_codec.Read(input);
+            if (bytesField_ == null || value != pb::ByteString.Empty) {
+              BytesField = value;
+            }
+            break;
+          }
+        }
+      }
+    }
+
+  }
+
+  [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+  public sealed partial class RepeatedWellKnownTypes : pb::IMessage<RepeatedWellKnownTypes> {
+    private static readonly pb::MessageParser<RepeatedWellKnownTypes> _parser = new pb::MessageParser<RepeatedWellKnownTypes>(() => new RepeatedWellKnownTypes());
+    public static pb::MessageParser<RepeatedWellKnownTypes> Parser { get { return _parser; } }
+
+    private static readonly string[] _fieldNames = new string[] { "any_field", "api_field", "bool_field", "bytes_field", "double_field", "duration_field", "empty_field", "field_mask_field", "float_field", "int32_field", "int64_field", "source_context_field", "string_field", "struct_field", "timestamp_field", "type_field", "uint32_field", "uint64_field" };
+    private static readonly uint[] _fieldTags = new uint[] { 10, 18, 130, 146, 82, 26, 34, 42, 90, 114, 98, 50, 138, 58, 66, 74, 122, 106 };
+    public static pbr::MessageDescriptor Descriptor {
+      get { return global::Google.Protobuf.TestProtos.UnittestWellKnownTypes.Descriptor.MessageTypes[1]; }
+    }
+
+    pbr::FieldAccessorTable pb::IReflectedMessage.Fields {
+      get { return global::Google.Protobuf.TestProtos.UnittestWellKnownTypes.internal__static_protobuf_unittest_RepeatedWellKnownTypes__FieldAccessorTable; }
+    }
+
+    private bool _frozen = false;
+    public bool IsFrozen { get { return _frozen; } }
+
+    public RepeatedWellKnownTypes() {
+      OnConstruction();
+    }
+
+    partial void OnConstruction();
+
+    public RepeatedWellKnownTypes(RepeatedWellKnownTypes other) : this() {
+      anyField_ = other.anyField_.Clone();
+      apiField_ = other.apiField_.Clone();
+      durationField_ = other.durationField_.Clone();
+      emptyField_ = other.emptyField_.Clone();
+      fieldMaskField_ = other.fieldMaskField_.Clone();
+      sourceContextField_ = other.sourceContextField_.Clone();
+      structField_ = other.structField_.Clone();
+      timestampField_ = other.timestampField_.Clone();
+      typeField_ = other.typeField_.Clone();
+      doubleField_ = other.doubleField_.Clone();
+      floatField_ = other.floatField_.Clone();
+      int64Field_ = other.int64Field_.Clone();
+      uint64Field_ = other.uint64Field_.Clone();
+      int32Field_ = other.int32Field_.Clone();
+      uint32Field_ = other.uint32Field_.Clone();
+      boolField_ = other.boolField_.Clone();
+      stringField_ = other.stringField_.Clone();
+      bytesField_ = other.bytesField_.Clone();
+    }
+
+    public RepeatedWellKnownTypes Clone() {
+      return new RepeatedWellKnownTypes(this);
+    }
+
+    public void Freeze() {
+      if (IsFrozen) {
+        return;
+      }
+      _frozen = true;
+      anyField_.Freeze();
+      apiField_.Freeze();
+      durationField_.Freeze();
+      emptyField_.Freeze();
+      fieldMaskField_.Freeze();
+      sourceContextField_.Freeze();
+      structField_.Freeze();
+      timestampField_.Freeze();
+      typeField_.Freeze();
+      doubleField_.Freeze();
+      floatField_.Freeze();
+      int64Field_.Freeze();
+      uint64Field_.Freeze();
+      int32Field_.Freeze();
+      uint32Field_.Freeze();
+      boolField_.Freeze();
+      stringField_.Freeze();
+      bytesField_.Freeze();
+    }
+
+    public const int AnyFieldFieldNumber = 1;
+    private static readonly pb::FieldCodec<global::Google.Protobuf.WellKnownTypes.Any> _repeated_anyField_codec
+        = pb::FieldCodec.ForMessage(10, global::Google.Protobuf.WellKnownTypes.Any.Parser);
+    private readonly pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Any> anyField_ = new pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Any>();
+    public pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Any> AnyField {
+      get { return anyField_; }
+    }
+
+    public const int ApiFieldFieldNumber = 2;
+    private static readonly pb::FieldCodec<global::Google.Protobuf.WellKnownTypes.Api> _repeated_apiField_codec
+        = pb::FieldCodec.ForMessage(18, global::Google.Protobuf.WellKnownTypes.Api.Parser);
+    private readonly pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Api> apiField_ = new pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Api>();
+    public pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Api> ApiField {
+      get { return apiField_; }
+    }
+
+    public const int DurationFieldFieldNumber = 3;
+    private static readonly pb::FieldCodec<global::Google.Protobuf.WellKnownTypes.Duration> _repeated_durationField_codec
+        = pb::FieldCodec.ForMessage(26, global::Google.Protobuf.WellKnownTypes.Duration.Parser);
+    private readonly pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Duration> durationField_ = new pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Duration>();
+    public pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Duration> DurationField {
+      get { return durationField_; }
+    }
+
+    public const int EmptyFieldFieldNumber = 4;
+    private static readonly pb::FieldCodec<global::Google.Protobuf.WellKnownTypes.Empty> _repeated_emptyField_codec
+        = pb::FieldCodec.ForMessage(34, global::Google.Protobuf.WellKnownTypes.Empty.Parser);
+    private readonly pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Empty> emptyField_ = new pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Empty>();
+    public pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Empty> EmptyField {
+      get { return emptyField_; }
+    }
+
+    public const int FieldMaskFieldFieldNumber = 5;
+    private static readonly pb::FieldCodec<global::Google.Protobuf.WellKnownTypes.FieldMask> _repeated_fieldMaskField_codec
+        = pb::FieldCodec.ForMessage(42, global::Google.Protobuf.WellKnownTypes.FieldMask.Parser);
+    private readonly pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.FieldMask> fieldMaskField_ = new pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.FieldMask>();
+    public pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.FieldMask> FieldMaskField {
+      get { return fieldMaskField_; }
+    }
+
+    public const int SourceContextFieldFieldNumber = 6;
+    private static readonly pb::FieldCodec<global::Google.Protobuf.WellKnownTypes.SourceContext> _repeated_sourceContextField_codec
+        = pb::FieldCodec.ForMessage(50, global::Google.Protobuf.WellKnownTypes.SourceContext.Parser);
+    private readonly pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.SourceContext> sourceContextField_ = new pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.SourceContext>();
+    public pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.SourceContext> SourceContextField {
+      get { return sourceContextField_; }
+    }
+
+    public const int StructFieldFieldNumber = 7;
+    private static readonly pb::FieldCodec<global::Google.Protobuf.WellKnownTypes.Struct> _repeated_structField_codec
+        = pb::FieldCodec.ForMessage(58, global::Google.Protobuf.WellKnownTypes.Struct.Parser);
+    private readonly pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Struct> structField_ = new pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Struct>();
+    public pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Struct> StructField {
+      get { return structField_; }
+    }
+
+    public const int TimestampFieldFieldNumber = 8;
+    private static readonly pb::FieldCodec<global::Google.Protobuf.WellKnownTypes.Timestamp> _repeated_timestampField_codec
+        = pb::FieldCodec.ForMessage(66, global::Google.Protobuf.WellKnownTypes.Timestamp.Parser);
+    private readonly pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Timestamp> timestampField_ = new pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Timestamp>();
+    public pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Timestamp> TimestampField {
+      get { return timestampField_; }
+    }
+
+    public const int TypeFieldFieldNumber = 9;
+    private static readonly pb::FieldCodec<global::Google.Protobuf.WellKnownTypes.Type> _repeated_typeField_codec
+        = pb::FieldCodec.ForMessage(74, global::Google.Protobuf.WellKnownTypes.Type.Parser);
+    private readonly pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Type> typeField_ = new pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Type>();
+    public pbc::RepeatedField<global::Google.Protobuf.WellKnownTypes.Type> TypeField {
+      get { return typeField_; }
+    }
+
+    public const int DoubleFieldFieldNumber = 10;
+    private static readonly pb::FieldCodec<double?> _repeated_doubleField_codec
+        = pb::FieldCodec.ForStructWrapper<double>(82);
+    private readonly pbc::RepeatedField<double?> doubleField_ = new pbc::RepeatedField<double?>();
+    public pbc::RepeatedField<double?> DoubleField {
+      get { return doubleField_; }
+    }
+
+    public const int FloatFieldFieldNumber = 11;
+    private static readonly pb::FieldCodec<float?> _repeated_floatField_codec
+        = pb::FieldCodec.ForStructWrapper<float>(90);
+    private readonly pbc::RepeatedField<float?> floatField_ = new pbc::RepeatedField<float?>();
+    public pbc::RepeatedField<float?> FloatField {
+      get { return floatField_; }
+    }
+
+    public const int Int64FieldFieldNumber = 12;
+    private static readonly pb::FieldCodec<long?> _repeated_int64Field_codec
+        = pb::FieldCodec.ForStructWrapper<long>(98);
+    private readonly pbc::RepeatedField<long?> int64Field_ = new pbc::RepeatedField<long?>();
+    public pbc::RepeatedField<long?> Int64Field {
+      get { return int64Field_; }
+    }
+
+    public const int Uint64FieldFieldNumber = 13;
+    private static readonly pb::FieldCodec<ulong?> _repeated_uint64Field_codec
+        = pb::FieldCodec.ForStructWrapper<ulong>(106);
+    private readonly pbc::RepeatedField<ulong?> uint64Field_ = new pbc::RepeatedField<ulong?>();
+    public pbc::RepeatedField<ulong?> Uint64Field {
+      get { return uint64Field_; }
+    }
+
+    public const int Int32FieldFieldNumber = 14;
+    private static readonly pb::FieldCodec<int?> _repeated_int32Field_codec
+        = pb::FieldCodec.ForStructWrapper<int>(114);
+    private readonly pbc::RepeatedField<int?> int32Field_ = new pbc::RepeatedField<int?>();
+    public pbc::RepeatedField<int?> Int32Field {
+      get { return int32Field_; }
+    }
+
+    public const int Uint32FieldFieldNumber = 15;
+    private static readonly pb::FieldCodec<uint?> _repeated_uint32Field_codec
+        = pb::FieldCodec.ForStructWrapper<uint>(122);
+    private readonly pbc::RepeatedField<uint?> uint32Field_ = new pbc::RepeatedField<uint?>();
+    public pbc::RepeatedField<uint?> Uint32Field {
+      get { return uint32Field_; }
+    }
+
+    public const int BoolFieldFieldNumber = 16;
+    private static readonly pb::FieldCodec<bool?> _repeated_boolField_codec
+        = pb::FieldCodec.ForStructWrapper<bool>(130);
+    private readonly pbc::RepeatedField<bool?> boolField_ = new pbc::RepeatedField<bool?>();
+    public pbc::RepeatedField<bool?> BoolField {
+      get { return boolField_; }
+    }
+
+    public const int StringFieldFieldNumber = 17;
+    private static readonly pb::FieldCodec<string> _repeated_stringField_codec
+        = pb::FieldCodec.ForClassWrapper<string>(138);
+    private readonly pbc::RepeatedField<string> stringField_ = new pbc::RepeatedField<string>();
+    public pbc::RepeatedField<string> StringField {
+      get { return stringField_; }
+    }
+
+    public const int BytesFieldFieldNumber = 18;
+    private static readonly pb::FieldCodec<pb::ByteString> _repeated_bytesField_codec
+        = pb::FieldCodec.ForClassWrapper<pb::ByteString>(146);
+    private readonly pbc::RepeatedField<pb::ByteString> bytesField_ = new pbc::RepeatedField<pb::ByteString>();
+    public pbc::RepeatedField<pb::ByteString> BytesField {
+      get { return bytesField_; }
+    }
+
+    public override bool Equals(object other) {
+      return Equals(other as RepeatedWellKnownTypes);
+    }
+
+    public bool Equals(RepeatedWellKnownTypes other) {
+      if (ReferenceEquals(other, null)) {
+        return false;
+      }
+      if (ReferenceEquals(other, this)) {
+        return true;
+      }
+      if(!anyField_.Equals(other.anyField_)) return false;
+      if(!apiField_.Equals(other.apiField_)) return false;
+      if(!durationField_.Equals(other.durationField_)) return false;
+      if(!emptyField_.Equals(other.emptyField_)) return false;
+      if(!fieldMaskField_.Equals(other.fieldMaskField_)) return false;
+      if(!sourceContextField_.Equals(other.sourceContextField_)) return false;
+      if(!structField_.Equals(other.structField_)) return false;
+      if(!timestampField_.Equals(other.timestampField_)) return false;
+      if(!typeField_.Equals(other.typeField_)) return false;
+      if(!doubleField_.Equals(other.doubleField_)) return false;
+      if(!floatField_.Equals(other.floatField_)) return false;
+      if(!int64Field_.Equals(other.int64Field_)) return false;
+      if(!uint64Field_.Equals(other.uint64Field_)) return false;
+      if(!int32Field_.Equals(other.int32Field_)) return false;
+      if(!uint32Field_.Equals(other.uint32Field_)) return false;
+      if(!boolField_.Equals(other.boolField_)) return false;
+      if(!stringField_.Equals(other.stringField_)) return false;
+      if(!bytesField_.Equals(other.bytesField_)) return false;
+      return true;
+    }
+
+    public override int GetHashCode() {
+      int hash = 1;
+      hash ^= anyField_.GetHashCode();
+      hash ^= apiField_.GetHashCode();
+      hash ^= durationField_.GetHashCode();
+      hash ^= emptyField_.GetHashCode();
+      hash ^= fieldMaskField_.GetHashCode();
+      hash ^= sourceContextField_.GetHashCode();
+      hash ^= structField_.GetHashCode();
+      hash ^= timestampField_.GetHashCode();
+      hash ^= typeField_.GetHashCode();
+      hash ^= doubleField_.GetHashCode();
+      hash ^= floatField_.GetHashCode();
+      hash ^= int64Field_.GetHashCode();
+      hash ^= uint64Field_.GetHashCode();
+      hash ^= int32Field_.GetHashCode();
+      hash ^= uint32Field_.GetHashCode();
+      hash ^= boolField_.GetHashCode();
+      hash ^= stringField_.GetHashCode();
+      hash ^= bytesField_.GetHashCode();
+      return hash;
+    }
+
+    public override string ToString() {
+      return pb::JsonFormatter.Default.Format(this);
+    }
+
+    public void WriteTo(pb::CodedOutputStream output) {
+      anyField_.WriteTo(output, _repeated_anyField_codec);
+      apiField_.WriteTo(output, _repeated_apiField_codec);
+      durationField_.WriteTo(output, _repeated_durationField_codec);
+      emptyField_.WriteTo(output, _repeated_emptyField_codec);
+      fieldMaskField_.WriteTo(output, _repeated_fieldMaskField_codec);
+      sourceContextField_.WriteTo(output, _repeated_sourceContextField_codec);
+      structField_.WriteTo(output, _repeated_structField_codec);
+      timestampField_.WriteTo(output, _repeated_timestampField_codec);
+      typeField_.WriteTo(output, _repeated_typeField_codec);
+      doubleField_.WriteTo(output, _repeated_doubleField_codec);
+      floatField_.WriteTo(output, _repeated_floatField_codec);
+      int64Field_.WriteTo(output, _repeated_int64Field_codec);
+      uint64Field_.WriteTo(output, _repeated_uint64Field_codec);
+      int32Field_.WriteTo(output, _repeated_int32Field_codec);
+      uint32Field_.WriteTo(output, _repeated_uint32Field_codec);
+      boolField_.WriteTo(output, _repeated_boolField_codec);
+      stringField_.WriteTo(output, _repeated_stringField_codec);
+      bytesField_.WriteTo(output, _repeated_bytesField_codec);
+    }
+
+    public int CalculateSize() {
+      int size = 0;
+      size += anyField_.CalculateSize(_repeated_anyField_codec);
+      size += apiField_.CalculateSize(_repeated_apiField_codec);
+      size += durationField_.CalculateSize(_repeated_durationField_codec);
+      size += emptyField_.CalculateSize(_repeated_emptyField_codec);
+      size += fieldMaskField_.CalculateSize(_repeated_fieldMaskField_codec);
+      size += sourceContextField_.CalculateSize(_repeated_sourceContextField_codec);
+      size += structField_.CalculateSize(_repeated_structField_codec);
+      size += timestampField_.CalculateSize(_repeated_timestampField_codec);
+      size += typeField_.CalculateSize(_repeated_typeField_codec);
+      size += doubleField_.CalculateSize(_repeated_doubleField_codec);
+      size += floatField_.CalculateSize(_repeated_floatField_codec);
+      size += int64Field_.CalculateSize(_repeated_int64Field_codec);
+      size += uint64Field_.CalculateSize(_repeated_uint64Field_codec);
+      size += int32Field_.CalculateSize(_repeated_int32Field_codec);
+      size += uint32Field_.CalculateSize(_repeated_uint32Field_codec);
+      size += boolField_.CalculateSize(_repeated_boolField_codec);
+      size += stringField_.CalculateSize(_repeated_stringField_codec);
+      size += bytesField_.CalculateSize(_repeated_bytesField_codec);
+      return size;
+    }
+
+    public void MergeFrom(RepeatedWellKnownTypes other) {
+      if (other == null) {
+        return;
+      }
+      anyField_.Add(other.anyField_);
+      apiField_.Add(other.apiField_);
+      durationField_.Add(other.durationField_);
+      emptyField_.Add(other.emptyField_);
+      fieldMaskField_.Add(other.fieldMaskField_);
+      sourceContextField_.Add(other.sourceContextField_);
+      structField_.Add(other.structField_);
+      timestampField_.Add(other.timestampField_);
+      typeField_.Add(other.typeField_);
+      doubleField_.Add(other.doubleField_);
+      floatField_.Add(other.floatField_);
+      int64Field_.Add(other.int64Field_);
+      uint64Field_.Add(other.uint64Field_);
+      int32Field_.Add(other.int32Field_);
+      uint32Field_.Add(other.uint32Field_);
+      boolField_.Add(other.boolField_);
+      stringField_.Add(other.stringField_);
+      bytesField_.Add(other.bytesField_);
+    }
+
+    public void MergeFrom(pb::CodedInputStream input) {
+      uint tag;
+      while (input.ReadTag(out tag)) {
+        switch(tag) {
+          case 0:
+            throw pb::InvalidProtocolBufferException.InvalidTag();
+          default:
+            if (pb::WireFormat.IsEndGroupTag(tag)) {
+              return;
+            }
+            break;
+          case 10: {
+            anyField_.AddEntriesFrom(input, _repeated_anyField_codec);
+            break;
+          }
+          case 18: {
+            apiField_.AddEntriesFrom(input, _repeated_apiField_codec);
+            break;
+          }
+          case 26: {
+            durationField_.AddEntriesFrom(input, _repeated_durationField_codec);
+            break;
+          }
+          case 34: {
+            emptyField_.AddEntriesFrom(input, _repeated_emptyField_codec);
+            break;
+          }
+          case 42: {
+            fieldMaskField_.AddEntriesFrom(input, _repeated_fieldMaskField_codec);
+            break;
+          }
+          case 50: {
+            sourceContextField_.AddEntriesFrom(input, _repeated_sourceContextField_codec);
+            break;
+          }
+          case 58: {
+            structField_.AddEntriesFrom(input, _repeated_structField_codec);
+            break;
+          }
+          case 66: {
+            timestampField_.AddEntriesFrom(input, _repeated_timestampField_codec);
+            break;
+          }
+          case 74: {
+            typeField_.AddEntriesFrom(input, _repeated_typeField_codec);
+            break;
+          }
+          case 82: {
+            doubleField_.AddEntriesFrom(input, _repeated_doubleField_codec);
+            break;
+          }
+          case 90: {
+            floatField_.AddEntriesFrom(input, _repeated_floatField_codec);
+            break;
+          }
+          case 98: {
+            int64Field_.AddEntriesFrom(input, _repeated_int64Field_codec);
+            break;
+          }
+          case 106: {
+            uint64Field_.AddEntriesFrom(input, _repeated_uint64Field_codec);
+            break;
+          }
+          case 114: {
+            int32Field_.AddEntriesFrom(input, _repeated_int32Field_codec);
+            break;
+          }
+          case 122: {
+            uint32Field_.AddEntriesFrom(input, _repeated_uint32Field_codec);
+            break;
+          }
+          case 130: {
+            boolField_.AddEntriesFrom(input, _repeated_boolField_codec);
+            break;
+          }
+          case 138: {
+            stringField_.AddEntriesFrom(input, _repeated_stringField_codec);
+            break;
+          }
+          case 146: {
+            bytesField_.AddEntriesFrom(input, _repeated_bytesField_codec);
+            break;
+          }
+        }
+      }
+    }
+
+  }
+
+  [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+  public sealed partial class OneofWellKnownTypes : pb::IMessage<OneofWellKnownTypes> {
+    private static readonly pb::MessageParser<OneofWellKnownTypes> _parser = new pb::MessageParser<OneofWellKnownTypes>(() => new OneofWellKnownTypes());
+    public static pb::MessageParser<OneofWellKnownTypes> Parser { get { return _parser; } }
+
+    private static readonly string[] _fieldNames = new string[] { "any_field", "api_field", "bool_field", "bytes_field", "double_field", "duration_field", "empty_field", "field_mask_field", "float_field", "int32_field", "int64_field", "source_context_field", "string_field", "struct_field", "timestamp_field", "type_field", "uint32_field", "uint64_field" };
+    private static readonly uint[] _fieldTags = new uint[] { 10, 18, 130, 146, 82, 26, 34, 42, 90, 114, 98, 50, 138, 58, 66, 74, 122, 106 };
+    public static pbr::MessageDescriptor Descriptor {
+      get { return global::Google.Protobuf.TestProtos.UnittestWellKnownTypes.Descriptor.MessageTypes[2]; }
+    }
+
+    pbr::FieldAccessorTable pb::IReflectedMessage.Fields {
+      get { return global::Google.Protobuf.TestProtos.UnittestWellKnownTypes.internal__static_protobuf_unittest_OneofWellKnownTypes__FieldAccessorTable; }
+    }
+
+    private bool _frozen = false;
+    public bool IsFrozen { get { return _frozen; } }
+
+    public OneofWellKnownTypes() {
+      OnConstruction();
+    }
+
+    partial void OnConstruction();
+
+    public OneofWellKnownTypes(OneofWellKnownTypes other) : this() {
+      switch (other.OneofFieldCase) {
+        case OneofFieldOneofCase.AnyField:
+          AnyField = other.AnyField.Clone();
+          break;
+        case OneofFieldOneofCase.ApiField:
+          ApiField = other.ApiField.Clone();
+          break;
+        case OneofFieldOneofCase.DurationField:
+          DurationField = other.DurationField.Clone();
+          break;
+        case OneofFieldOneofCase.EmptyField:
+          EmptyField = other.EmptyField.Clone();
+          break;
+        case OneofFieldOneofCase.FieldMaskField:
+          FieldMaskField = other.FieldMaskField.Clone();
+          break;
+        case OneofFieldOneofCase.SourceContextField:
+          SourceContextField = other.SourceContextField.Clone();
+          break;
+        case OneofFieldOneofCase.StructField:
+          StructField = other.StructField.Clone();
+          break;
+        case OneofFieldOneofCase.TimestampField:
+          TimestampField = other.TimestampField.Clone();
+          break;
+        case OneofFieldOneofCase.TypeField:
+          TypeField = other.TypeField.Clone();
+          break;
+        case OneofFieldOneofCase.DoubleField:
+          DoubleField = other.DoubleField;
+          break;
+        case OneofFieldOneofCase.FloatField:
+          FloatField = other.FloatField;
+          break;
+        case OneofFieldOneofCase.Int64Field:
+          Int64Field = other.Int64Field;
+          break;
+        case OneofFieldOneofCase.Uint64Field:
+          Uint64Field = other.Uint64Field;
+          break;
+        case OneofFieldOneofCase.Int32Field:
+          Int32Field = other.Int32Field;
+          break;
+        case OneofFieldOneofCase.Uint32Field:
+          Uint32Field = other.Uint32Field;
+          break;
+        case OneofFieldOneofCase.BoolField:
+          BoolField = other.BoolField;
+          break;
+        case OneofFieldOneofCase.StringField:
+          StringField = other.StringField;
+          break;
+        case OneofFieldOneofCase.BytesField:
+          BytesField = other.BytesField;
+          break;
+      }
+
+    }
+
+    public OneofWellKnownTypes Clone() {
+      return new OneofWellKnownTypes(this);
+    }
+
+    public void Freeze() {
+      if (IsFrozen) {
+        return;
+      }
+      _frozen = true;
+      if (oneofField_ is IFreezable) ((IFreezable) oneofField_).Freeze();
+    }
+
+    public const int AnyFieldFieldNumber = 1;
+    public global::Google.Protobuf.WellKnownTypes.Any AnyField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.AnyField ? (global::Google.Protobuf.WellKnownTypes.Any) oneofField_ : null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.AnyField;
+      }
+    }
+
+    public const int ApiFieldFieldNumber = 2;
+    public global::Google.Protobuf.WellKnownTypes.Api ApiField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.ApiField ? (global::Google.Protobuf.WellKnownTypes.Api) oneofField_ : null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.ApiField;
+      }
+    }
+
+    public const int DurationFieldFieldNumber = 3;
+    public global::Google.Protobuf.WellKnownTypes.Duration DurationField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.DurationField ? (global::Google.Protobuf.WellKnownTypes.Duration) oneofField_ : null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.DurationField;
+      }
+    }
+
+    public const int EmptyFieldFieldNumber = 4;
+    public global::Google.Protobuf.WellKnownTypes.Empty EmptyField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.EmptyField ? (global::Google.Protobuf.WellKnownTypes.Empty) oneofField_ : null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.EmptyField;
+      }
+    }
+
+    public const int FieldMaskFieldFieldNumber = 5;
+    public global::Google.Protobuf.WellKnownTypes.FieldMask FieldMaskField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.FieldMaskField ? (global::Google.Protobuf.WellKnownTypes.FieldMask) oneofField_ : null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.FieldMaskField;
+      }
+    }
+
+    public const int SourceContextFieldFieldNumber = 6;
+    public global::Google.Protobuf.WellKnownTypes.SourceContext SourceContextField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.SourceContextField ? (global::Google.Protobuf.WellKnownTypes.SourceContext) oneofField_ : null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.SourceContextField;
+      }
+    }
+
+    public const int StructFieldFieldNumber = 7;
+    public global::Google.Protobuf.WellKnownTypes.Struct StructField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.StructField ? (global::Google.Protobuf.WellKnownTypes.Struct) oneofField_ : null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.StructField;
+      }
+    }
+
+    public const int TimestampFieldFieldNumber = 8;
+    public global::Google.Protobuf.WellKnownTypes.Timestamp TimestampField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.TimestampField ? (global::Google.Protobuf.WellKnownTypes.Timestamp) oneofField_ : null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.TimestampField;
+      }
+    }
+
+    public const int TypeFieldFieldNumber = 9;
+    public global::Google.Protobuf.WellKnownTypes.Type TypeField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.TypeField ? (global::Google.Protobuf.WellKnownTypes.Type) oneofField_ : null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.TypeField;
+      }
+    }
+
+    public const int DoubleFieldFieldNumber = 10;
+    private static readonly pb::FieldCodec<double?> _oneof_doubleField_codec = pb::FieldCodec.ForStructWrapper<double>(82);
+    public double? DoubleField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.DoubleField ? (double?) oneofField_ : (double?) null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.DoubleField;
+      }
+    }
+
+    public const int FloatFieldFieldNumber = 11;
+    private static readonly pb::FieldCodec<float?> _oneof_floatField_codec = pb::FieldCodec.ForStructWrapper<float>(90);
+    public float? FloatField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.FloatField ? (float?) oneofField_ : (float?) null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.FloatField;
+      }
+    }
+
+    public const int Int64FieldFieldNumber = 12;
+    private static readonly pb::FieldCodec<long?> _oneof_int64Field_codec = pb::FieldCodec.ForStructWrapper<long>(98);
+    public long? Int64Field {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.Int64Field ? (long?) oneofField_ : (long?) null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.Int64Field;
+      }
+    }
+
+    public const int Uint64FieldFieldNumber = 13;
+    private static readonly pb::FieldCodec<ulong?> _oneof_uint64Field_codec = pb::FieldCodec.ForStructWrapper<ulong>(106);
+    public ulong? Uint64Field {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.Uint64Field ? (ulong?) oneofField_ : (ulong?) null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.Uint64Field;
+      }
+    }
+
+    public const int Int32FieldFieldNumber = 14;
+    private static readonly pb::FieldCodec<int?> _oneof_int32Field_codec = pb::FieldCodec.ForStructWrapper<int>(114);
+    public int? Int32Field {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.Int32Field ? (int?) oneofField_ : (int?) null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.Int32Field;
+      }
+    }
+
+    public const int Uint32FieldFieldNumber = 15;
+    private static readonly pb::FieldCodec<uint?> _oneof_uint32Field_codec = pb::FieldCodec.ForStructWrapper<uint>(122);
+    public uint? Uint32Field {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.Uint32Field ? (uint?) oneofField_ : (uint?) null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.Uint32Field;
+      }
+    }
+
+    public const int BoolFieldFieldNumber = 16;
+    private static readonly pb::FieldCodec<bool?> _oneof_boolField_codec = pb::FieldCodec.ForStructWrapper<bool>(130);
+    public bool? BoolField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.BoolField ? (bool?) oneofField_ : (bool?) null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.BoolField;
+      }
+    }
+
+    public const int StringFieldFieldNumber = 17;
+    private static readonly pb::FieldCodec<string> _oneof_stringField_codec = pb::FieldCodec.ForClassWrapper<string>(138);
+    public string StringField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.StringField ? (string) oneofField_ : (string) null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.StringField;
+      }
+    }
+
+    public const int BytesFieldFieldNumber = 18;
+    private static readonly pb::FieldCodec<pb::ByteString> _oneof_bytesField_codec = pb::FieldCodec.ForClassWrapper<pb::ByteString>(146);
+    public pb::ByteString BytesField {
+      get { return oneofFieldCase_ == OneofFieldOneofCase.BytesField ? (pb::ByteString) oneofField_ : (pb::ByteString) null; }
+      set {
+        pb::Freezable.CheckMutable(this);
+        oneofField_ = value;
+        oneofFieldCase_ = value == null ? OneofFieldOneofCase.None : OneofFieldOneofCase.BytesField;
+      }
+    }
+
+    private object oneofField_;
+    public enum OneofFieldOneofCase {
+      None = 0,
+      AnyField = 1,
+      ApiField = 2,
+      DurationField = 3,
+      EmptyField = 4,
+      FieldMaskField = 5,
+      SourceContextField = 6,
+      StructField = 7,
+      TimestampField = 8,
+      TypeField = 9,
+      DoubleField = 10,
+      FloatField = 11,
+      Int64Field = 12,
+      Uint64Field = 13,
+      Int32Field = 14,
+      Uint32Field = 15,
+      BoolField = 16,
+      StringField = 17,
+      BytesField = 18,
+    }
+    private OneofFieldOneofCase oneofFieldCase_ = OneofFieldOneofCase.None;
+    public OneofFieldOneofCase OneofFieldCase {
+      get { return oneofFieldCase_; }
+    }
+
+    public void ClearOneofField() {
+      pb::Freezable.CheckMutable(this);
+      oneofFieldCase_ = OneofFieldOneofCase.None;
+      oneofField_ = null;
+    }
+
+    public override bool Equals(object other) {
+      return Equals(other as OneofWellKnownTypes);
+    }
+
+    public bool Equals(OneofWellKnownTypes other) {
+      if (ReferenceEquals(other, null)) {
+        return false;
+      }
+      if (ReferenceEquals(other, this)) {
+        return true;
+      }
+      if (!object.Equals(AnyField, other.AnyField)) return false;
+      if (!object.Equals(ApiField, other.ApiField)) return false;
+      if (!object.Equals(DurationField, other.DurationField)) return false;
+      if (!object.Equals(EmptyField, other.EmptyField)) return false;
+      if (!object.Equals(FieldMaskField, other.FieldMaskField)) return false;
+      if (!object.Equals(SourceContextField, other.SourceContextField)) return false;
+      if (!object.Equals(StructField, other.StructField)) return false;
+      if (!object.Equals(TimestampField, other.TimestampField)) return false;
+      if (!object.Equals(TypeField, other.TypeField)) return false;
+      if (DoubleField != other.DoubleField) return false;
+      if (FloatField != other.FloatField) return false;
+      if (Int64Field != other.Int64Field) return false;
+      if (Uint64Field != other.Uint64Field) return false;
+      if (Int32Field != other.Int32Field) return false;
+      if (Uint32Field != other.Uint32Field) return false;
+      if (BoolField != other.BoolField) return false;
+      if (StringField != other.StringField) return false;
+      if (BytesField != other.BytesField) return false;
+      return true;
+    }
+
+    public override int GetHashCode() {
+      int hash = 1;
+      if (oneofFieldCase_ == OneofFieldOneofCase.AnyField) hash ^= AnyField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.ApiField) hash ^= ApiField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.DurationField) hash ^= DurationField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.EmptyField) hash ^= EmptyField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.FieldMaskField) hash ^= FieldMaskField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.SourceContextField) hash ^= SourceContextField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.StructField) hash ^= StructField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.TimestampField) hash ^= TimestampField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.TypeField) hash ^= TypeField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.DoubleField) hash ^= DoubleField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.FloatField) hash ^= FloatField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.Int64Field) hash ^= Int64Field.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.Uint64Field) hash ^= Uint64Field.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.Int32Field) hash ^= Int32Field.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.Uint32Field) hash ^= Uint32Field.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.BoolField) hash ^= BoolField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.StringField) hash ^= StringField.GetHashCode();
+      if (oneofFieldCase_ == OneofFieldOneofCase.BytesField) hash ^= BytesField.GetHashCode();
+      return hash;
+    }
+
+    public override string ToString() {
+      return pb::JsonFormatter.Default.Format(this);
+    }
+
+    public void WriteTo(pb::CodedOutputStream output) {
+      if (oneofFieldCase_ == OneofFieldOneofCase.AnyField) {
+        output.WriteRawTag(10);
+        output.WriteMessage(AnyField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.ApiField) {
+        output.WriteRawTag(18);
+        output.WriteMessage(ApiField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.DurationField) {
+        output.WriteRawTag(26);
+        output.WriteMessage(DurationField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.EmptyField) {
+        output.WriteRawTag(34);
+        output.WriteMessage(EmptyField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.FieldMaskField) {
+        output.WriteRawTag(42);
+        output.WriteMessage(FieldMaskField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.SourceContextField) {
+        output.WriteRawTag(50);
+        output.WriteMessage(SourceContextField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.StructField) {
+        output.WriteRawTag(58);
+        output.WriteMessage(StructField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.TimestampField) {
+        output.WriteRawTag(66);
+        output.WriteMessage(TimestampField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.TypeField) {
+        output.WriteRawTag(74);
+        output.WriteMessage(TypeField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.DoubleField) {
+        _oneof_doubleField_codec.WriteTagAndValue(output, (double?) oneofField_);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.FloatField) {
+        _oneof_floatField_codec.WriteTagAndValue(output, (float?) oneofField_);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.Int64Field) {
+        _oneof_int64Field_codec.WriteTagAndValue(output, (long?) oneofField_);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.Uint64Field) {
+        _oneof_uint64Field_codec.WriteTagAndValue(output, (ulong?) oneofField_);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.Int32Field) {
+        _oneof_int32Field_codec.WriteTagAndValue(output, (int?) oneofField_);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.Uint32Field) {
+        _oneof_uint32Field_codec.WriteTagAndValue(output, (uint?) oneofField_);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.BoolField) {
+        _oneof_boolField_codec.WriteTagAndValue(output, (bool?) oneofField_);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.StringField) {
+        _oneof_stringField_codec.WriteTagAndValue(output, (string) oneofField_);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.BytesField) {
+        _oneof_bytesField_codec.WriteTagAndValue(output, (pb::ByteString) oneofField_);
+      }
+    }
+
+    public int CalculateSize() {
+      int size = 0;
+      if (oneofFieldCase_ == OneofFieldOneofCase.AnyField) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(AnyField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.ApiField) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(ApiField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.DurationField) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(DurationField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.EmptyField) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(EmptyField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.FieldMaskField) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(FieldMaskField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.SourceContextField) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(SourceContextField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.StructField) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(StructField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.TimestampField) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(TimestampField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.TypeField) {
+        size += 1 + pb::CodedOutputStream.ComputeMessageSize(TypeField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.DoubleField) {
+        size += _oneof_doubleField_codec.CalculateSizeWithTag(DoubleField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.FloatField) {
+        size += _oneof_floatField_codec.CalculateSizeWithTag(FloatField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.Int64Field) {
+        size += _oneof_int64Field_codec.CalculateSizeWithTag(Int64Field);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.Uint64Field) {
+        size += _oneof_uint64Field_codec.CalculateSizeWithTag(Uint64Field);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.Int32Field) {
+        size += _oneof_int32Field_codec.CalculateSizeWithTag(Int32Field);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.Uint32Field) {
+        size += _oneof_uint32Field_codec.CalculateSizeWithTag(Uint32Field);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.BoolField) {
+        size += _oneof_boolField_codec.CalculateSizeWithTag(BoolField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.StringField) {
+        size += _oneof_stringField_codec.CalculateSizeWithTag(StringField);
+      }
+      if (oneofFieldCase_ == OneofFieldOneofCase.BytesField) {
+        size += _oneof_bytesField_codec.CalculateSizeWithTag(BytesField);
+      }
+      return size;
+    }
+
+    public void MergeFrom(OneofWellKnownTypes other) {
+      if (other == null) {
+        return;
+      }
+      switch (other.OneofFieldCase) {
+        case OneofFieldOneofCase.AnyField:
+          AnyField = other.AnyField;
+          break;
+        case OneofFieldOneofCase.ApiField:
+          ApiField = other.ApiField;
+          break;
+        case OneofFieldOneofCase.DurationField:
+          DurationField = other.DurationField;
+          break;
+        case OneofFieldOneofCase.EmptyField:
+          EmptyField = other.EmptyField;
+          break;
+        case OneofFieldOneofCase.FieldMaskField:
+          FieldMaskField = other.FieldMaskField;
+          break;
+        case OneofFieldOneofCase.SourceContextField:
+          SourceContextField = other.SourceContextField;
+          break;
+        case OneofFieldOneofCase.StructField:
+          StructField = other.StructField;
+          break;
+        case OneofFieldOneofCase.TimestampField:
+          TimestampField = other.TimestampField;
+          break;
+        case OneofFieldOneofCase.TypeField:
+          TypeField = other.TypeField;
+          break;
+        case OneofFieldOneofCase.DoubleField:
+          DoubleField = other.DoubleField;
+          break;
+        case OneofFieldOneofCase.FloatField:
+          FloatField = other.FloatField;
+          break;
+        case OneofFieldOneofCase.Int64Field:
+          Int64Field = other.Int64Field;
+          break;
+        case OneofFieldOneofCase.Uint64Field:
+          Uint64Field = other.Uint64Field;
+          break;
+        case OneofFieldOneofCase.Int32Field:
+          Int32Field = other.Int32Field;
+          break;
+        case OneofFieldOneofCase.Uint32Field:
+          Uint32Field = other.Uint32Field;
+          break;
+        case OneofFieldOneofCase.BoolField:
+          BoolField = other.BoolField;
+          break;
+        case OneofFieldOneofCase.StringField:
+          StringField = other.StringField;
+          break;
+        case OneofFieldOneofCase.BytesField:
+          BytesField = other.BytesField;
+          break;
+      }
+
+    }
+
+    public void MergeFrom(pb::CodedInputStream input) {
+      uint tag;
+      while (input.ReadTag(out tag)) {
+        switch(tag) {
+          case 0:
+            throw pb::InvalidProtocolBufferException.InvalidTag();
+          default:
+            if (pb::WireFormat.IsEndGroupTag(tag)) {
+              return;
+            }
+            break;
+          case 10: {
+            global::Google.Protobuf.WellKnownTypes.Any subBuilder = new global::Google.Protobuf.WellKnownTypes.Any();
+            if (oneofFieldCase_ == OneofFieldOneofCase.AnyField) {
+              subBuilder.MergeFrom(AnyField);
+            }
+            input.ReadMessage(subBuilder);
+            AnyField = subBuilder;
+            break;
+          }
+          case 18: {
+            global::Google.Protobuf.WellKnownTypes.Api subBuilder = new global::Google.Protobuf.WellKnownTypes.Api();
+            if (oneofFieldCase_ == OneofFieldOneofCase.ApiField) {
+              subBuilder.MergeFrom(ApiField);
+            }
+            input.ReadMessage(subBuilder);
+            ApiField = subBuilder;
+            break;
+          }
+          case 26: {
+            global::Google.Protobuf.WellKnownTypes.Duration subBuilder = new global::Google.Protobuf.WellKnownTypes.Duration();
+            if (oneofFieldCase_ == OneofFieldOneofCase.DurationField) {
+              subBuilder.MergeFrom(DurationField);
+            }
+            input.ReadMessage(subBuilder);
+            DurationField = subBuilder;
+            break;
+          }
+          case 34: {
+            global::Google.Protobuf.WellKnownTypes.Empty subBuilder = new global::Google.Protobuf.WellKnownTypes.Empty();
+            if (oneofFieldCase_ == OneofFieldOneofCase.EmptyField) {
+              subBuilder.MergeFrom(EmptyField);
+            }
+            input.ReadMessage(subBuilder);
+            EmptyField = subBuilder;
+            break;
+          }
+          case 42: {
+            global::Google.Protobuf.WellKnownTypes.FieldMask subBuilder = new global::Google.Protobuf.WellKnownTypes.FieldMask();
+            if (oneofFieldCase_ == OneofFieldOneofCase.FieldMaskField) {
+              subBuilder.MergeFrom(FieldMaskField);
+            }
+            input.ReadMessage(subBuilder);
+            FieldMaskField = subBuilder;
+            break;
+          }
+          case 50: {
+            global::Google.Protobuf.WellKnownTypes.SourceContext subBuilder = new global::Google.Protobuf.WellKnownTypes.SourceContext();
+            if (oneofFieldCase_ == OneofFieldOneofCase.SourceContextField) {
+              subBuilder.MergeFrom(SourceContextField);
+            }
+            input.ReadMessage(subBuilder);
+            SourceContextField = subBuilder;
+            break;
+          }
+          case 58: {
+            global::Google.Protobuf.WellKnownTypes.Struct subBuilder = new global::Google.Protobuf.WellKnownTypes.Struct();
+            if (oneofFieldCase_ == OneofFieldOneofCase.StructField) {
+              subBuilder.MergeFrom(StructField);
+            }
+            input.ReadMessage(subBuilder);
+            StructField = subBuilder;
+            break;
+          }
+          case 66: {
+            global::Google.Protobuf.WellKnownTypes.Timestamp subBuilder = new global::Google.Protobuf.WellKnownTypes.Timestamp();
+            if (oneofFieldCase_ == OneofFieldOneofCase.TimestampField) {
+              subBuilder.MergeFrom(TimestampField);
+            }
+            input.ReadMessage(subBuilder);
+            TimestampField = subBuilder;
+            break;
+          }
+          case 74: {
+            global::Google.Protobuf.WellKnownTypes.Type subBuilder = new global::Google.Protobuf.WellKnownTypes.Type();
+            if (oneofFieldCase_ == OneofFieldOneofCase.TypeField) {
+              subBuilder.MergeFrom(TypeField);
+            }
+            input.ReadMessage(subBuilder);
+            TypeField = subBuilder;
+            break;
+          }
+          case 82: {
+            DoubleField = _oneof_doubleField_codec.Read(input);
+            break;
+          }
+          case 90: {
+            FloatField = _oneof_floatField_codec.Read(input);
+            break;
+          }
+          case 98: {
+            Int64Field = _oneof_int64Field_codec.Read(input);
+            break;
+          }
+          case 106: {
+            Uint64Field = _oneof_uint64Field_codec.Read(input);
+            break;
+          }
+          case 114: {
+            Int32Field = _oneof_int32Field_codec.Read(input);
+            break;
+          }
+          case 122: {
+            Uint32Field = _oneof_uint32Field_codec.Read(input);
+            break;
+          }
+          case 130: {
+            BoolField = _oneof_boolField_codec.Read(input);
+            break;
+          }
+          case 138: {
+            StringField = _oneof_stringField_codec.Read(input);
+            break;
+          }
+          case 146: {
+            BytesField = _oneof_bytesField_codec.Read(input);
+            break;
+          }
+        }
+      }
+    }
+
+  }
+
+  [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+  public sealed partial class MapWellKnownTypes : pb::IMessage<MapWellKnownTypes> {
+    private static readonly pb::MessageParser<MapWellKnownTypes> _parser = new pb::MessageParser<MapWellKnownTypes>(() => new MapWellKnownTypes());
+    public static pb::MessageParser<MapWellKnownTypes> Parser { get { return _parser; } }
+
+    private static readonly string[] _fieldNames = new string[] { "any_field", "api_field", "bool_field", "bytes_field", "double_field", "duration_field", "empty_field", "field_mask_field", "float_field", "int32_field", "int64_field", "source_context_field", "string_field", "struct_field", "timestamp_field", "type_field", "uint32_field", "uint64_field" };
+    private static readonly uint[] _fieldTags = new uint[] { 10, 18, 130, 146, 82, 26, 34, 42, 90, 114, 98, 50, 138, 58, 66, 74, 122, 106 };
+    public static pbr::MessageDescriptor Descriptor {
+      get { return global::Google.Protobuf.TestProtos.UnittestWellKnownTypes.Descriptor.MessageTypes[3]; }
+    }
+
+    pbr::FieldAccessorTable pb::IReflectedMessage.Fields {
+      get { return global::Google.Protobuf.TestProtos.UnittestWellKnownTypes.internal__static_protobuf_unittest_MapWellKnownTypes__FieldAccessorTable; }
+    }
+
+    private bool _frozen = false;
+    public bool IsFrozen { get { return _frozen; } }
+
+    public MapWellKnownTypes() {
+      OnConstruction();
+    }
+
+    partial void OnConstruction();
+
+    public MapWellKnownTypes(MapWellKnownTypes other) : this() {
+      anyField_ = other.anyField_.Clone();
+      apiField_ = other.apiField_.Clone();
+      durationField_ = other.durationField_.Clone();
+      emptyField_ = other.emptyField_.Clone();
+      fieldMaskField_ = other.fieldMaskField_.Clone();
+      sourceContextField_ = other.sourceContextField_.Clone();
+      structField_ = other.structField_.Clone();
+      timestampField_ = other.timestampField_.Clone();
+      typeField_ = other.typeField_.Clone();
+      doubleField_ = other.doubleField_.Clone();
+      floatField_ = other.floatField_.Clone();
+      int64Field_ = other.int64Field_.Clone();
+      uint64Field_ = other.uint64Field_.Clone();
+      int32Field_ = other.int32Field_.Clone();
+      uint32Field_ = other.uint32Field_.Clone();
+      boolField_ = other.boolField_.Clone();
+      stringField_ = other.stringField_.Clone();
+      bytesField_ = other.bytesField_.Clone();
+    }
+
+    public MapWellKnownTypes Clone() {
+      return new MapWellKnownTypes(this);
+    }
+
+    public void Freeze() {
+      if (IsFrozen) {
+        return;
+      }
+      _frozen = true;
+      anyField_.Freeze();
+      apiField_.Freeze();
+      durationField_.Freeze();
+      emptyField_.Freeze();
+      fieldMaskField_.Freeze();
+      sourceContextField_.Freeze();
+      structField_.Freeze();
+      timestampField_.Freeze();
+      typeField_.Freeze();
+      doubleField_.Freeze();
+      floatField_.Freeze();
+      int64Field_.Freeze();
+      uint64Field_.Freeze();
+      int32Field_.Freeze();
+      uint32Field_.Freeze();
+      boolField_.Freeze();
+      stringField_.Freeze();
+      bytesField_.Freeze();
+    }
+
+    public const int AnyFieldFieldNumber = 1;
+    private static readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Any>.Codec _map_anyField_codec
+        = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Any>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForMessage(18, global::Google.Protobuf.WellKnownTypes.Any.Parser), 10);
+    private readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Any> anyField_ = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Any>();
+    public pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Any> AnyField {
+      get { return anyField_; }
+    }
+
+    public const int ApiFieldFieldNumber = 2;
+    private static readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Api>.Codec _map_apiField_codec
+        = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Api>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForMessage(18, global::Google.Protobuf.WellKnownTypes.Api.Parser), 18);
+    private readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Api> apiField_ = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Api>();
+    public pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Api> ApiField {
+      get { return apiField_; }
+    }
+
+    public const int DurationFieldFieldNumber = 3;
+    private static readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Duration>.Codec _map_durationField_codec
+        = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Duration>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForMessage(18, global::Google.Protobuf.WellKnownTypes.Duration.Parser), 26);
+    private readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Duration> durationField_ = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Duration>();
+    public pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Duration> DurationField {
+      get { return durationField_; }
+    }
+
+    public const int EmptyFieldFieldNumber = 4;
+    private static readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Empty>.Codec _map_emptyField_codec
+        = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Empty>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForMessage(18, global::Google.Protobuf.WellKnownTypes.Empty.Parser), 34);
+    private readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Empty> emptyField_ = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Empty>();
+    public pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Empty> EmptyField {
+      get { return emptyField_; }
+    }
+
+    public const int FieldMaskFieldFieldNumber = 5;
+    private static readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.FieldMask>.Codec _map_fieldMaskField_codec
+        = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.FieldMask>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForMessage(18, global::Google.Protobuf.WellKnownTypes.FieldMask.Parser), 42);
+    private readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.FieldMask> fieldMaskField_ = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.FieldMask>();
+    public pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.FieldMask> FieldMaskField {
+      get { return fieldMaskField_; }
+    }
+
+    public const int SourceContextFieldFieldNumber = 6;
+    private static readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.SourceContext>.Codec _map_sourceContextField_codec
+        = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.SourceContext>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForMessage(18, global::Google.Protobuf.WellKnownTypes.SourceContext.Parser), 50);
+    private readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.SourceContext> sourceContextField_ = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.SourceContext>();
+    public pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.SourceContext> SourceContextField {
+      get { return sourceContextField_; }
+    }
+
+    public const int StructFieldFieldNumber = 7;
+    private static readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Struct>.Codec _map_structField_codec
+        = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Struct>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForMessage(18, global::Google.Protobuf.WellKnownTypes.Struct.Parser), 58);
+    private readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Struct> structField_ = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Struct>();
+    public pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Struct> StructField {
+      get { return structField_; }
+    }
+
+    public const int TimestampFieldFieldNumber = 8;
+    private static readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Timestamp>.Codec _map_timestampField_codec
+        = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Timestamp>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForMessage(18, global::Google.Protobuf.WellKnownTypes.Timestamp.Parser), 66);
+    private readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Timestamp> timestampField_ = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Timestamp>();
+    public pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Timestamp> TimestampField {
+      get { return timestampField_; }
+    }
+
+    public const int TypeFieldFieldNumber = 9;
+    private static readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Type>.Codec _map_typeField_codec
+        = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Type>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForMessage(18, global::Google.Protobuf.WellKnownTypes.Type.Parser), 74);
+    private readonly pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Type> typeField_ = new pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Type>();
+    public pbc::MapField<int, global::Google.Protobuf.WellKnownTypes.Type> TypeField {
+      get { return typeField_; }
+    }
+
+    public const int DoubleFieldFieldNumber = 10;
+    private static readonly pbc::MapField<int, double?>.Codec _map_doubleField_codec
+        = new pbc::MapField<int, double?>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForStructWrapper<double>(18), 82);
+    private readonly pbc::MapField<int, double?> doubleField_ = new pbc::MapField<int, double?>(true);
+    public pbc::MapField<int, double?> DoubleField {
+      get { return doubleField_; }
+    }
+
+    public const int FloatFieldFieldNumber = 11;
+    private static readonly pbc::MapField<int, float?>.Codec _map_floatField_codec
+        = new pbc::MapField<int, float?>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForStructWrapper<float>(18), 90);
+    private readonly pbc::MapField<int, float?> floatField_ = new pbc::MapField<int, float?>(true);
+    public pbc::MapField<int, float?> FloatField {
+      get { return floatField_; }
+    }
+
+    public const int Int64FieldFieldNumber = 12;
+    private static readonly pbc::MapField<int, long?>.Codec _map_int64Field_codec
+        = new pbc::MapField<int, long?>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForStructWrapper<long>(18), 98);
+    private readonly pbc::MapField<int, long?> int64Field_ = new pbc::MapField<int, long?>(true);
+    public pbc::MapField<int, long?> Int64Field {
+      get { return int64Field_; }
+    }
+
+    public const int Uint64FieldFieldNumber = 13;
+    private static readonly pbc::MapField<int, ulong?>.Codec _map_uint64Field_codec
+        = new pbc::MapField<int, ulong?>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForStructWrapper<ulong>(18), 106);
+    private readonly pbc::MapField<int, ulong?> uint64Field_ = new pbc::MapField<int, ulong?>(true);
+    public pbc::MapField<int, ulong?> Uint64Field {
+      get { return uint64Field_; }
+    }
+
+    public const int Int32FieldFieldNumber = 14;
+    private static readonly pbc::MapField<int, int?>.Codec _map_int32Field_codec
+        = new pbc::MapField<int, int?>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForStructWrapper<int>(18), 114);
+    private readonly pbc::MapField<int, int?> int32Field_ = new pbc::MapField<int, int?>(true);
+    public pbc::MapField<int, int?> Int32Field {
+      get { return int32Field_; }
+    }
+
+    public const int Uint32FieldFieldNumber = 15;
+    private static readonly pbc::MapField<int, uint?>.Codec _map_uint32Field_codec
+        = new pbc::MapField<int, uint?>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForStructWrapper<uint>(18), 122);
+    private readonly pbc::MapField<int, uint?> uint32Field_ = new pbc::MapField<int, uint?>(true);
+    public pbc::MapField<int, uint?> Uint32Field {
+      get { return uint32Field_; }
+    }
+
+    public const int BoolFieldFieldNumber = 16;
+    private static readonly pbc::MapField<int, bool?>.Codec _map_boolField_codec
+        = new pbc::MapField<int, bool?>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForStructWrapper<bool>(18), 130);
+    private readonly pbc::MapField<int, bool?> boolField_ = new pbc::MapField<int, bool?>(true);
+    public pbc::MapField<int, bool?> BoolField {
+      get { return boolField_; }
+    }
+
+    public const int StringFieldFieldNumber = 17;
+    private static readonly pbc::MapField<int, string>.Codec _map_stringField_codec
+        = new pbc::MapField<int, string>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForClassWrapper<string>(18), 138);
+    private readonly pbc::MapField<int, string> stringField_ = new pbc::MapField<int, string>(true);
+    public pbc::MapField<int, string> StringField {
+      get { return stringField_; }
+    }
+
+    public const int BytesFieldFieldNumber = 18;
+    private static readonly pbc::MapField<int, pb::ByteString>.Codec _map_bytesField_codec
+        = new pbc::MapField<int, pb::ByteString>.Codec(pb::FieldCodec.ForInt32(8), pb::FieldCodec.ForClassWrapper<pb::ByteString>(18), 146);
+    private readonly pbc::MapField<int, pb::ByteString> bytesField_ = new pbc::MapField<int, pb::ByteString>(true);
+    public pbc::MapField<int, pb::ByteString> BytesField {
+      get { return bytesField_; }
+    }
+
+    public override bool Equals(object other) {
+      return Equals(other as MapWellKnownTypes);
+    }
+
+    public bool Equals(MapWellKnownTypes other) {
+      if (ReferenceEquals(other, null)) {
+        return false;
+      }
+      if (ReferenceEquals(other, this)) {
+        return true;
+      }
+      if (!AnyField.Equals(other.AnyField)) return false;
+      if (!ApiField.Equals(other.ApiField)) return false;
+      if (!DurationField.Equals(other.DurationField)) return false;
+      if (!EmptyField.Equals(other.EmptyField)) return false;
+      if (!FieldMaskField.Equals(other.FieldMaskField)) return false;
+      if (!SourceContextField.Equals(other.SourceContextField)) return false;
+      if (!StructField.Equals(other.StructField)) return false;
+      if (!TimestampField.Equals(other.TimestampField)) return false;
+      if (!TypeField.Equals(other.TypeField)) return false;
+      if (!DoubleField.Equals(other.DoubleField)) return false;
+      if (!FloatField.Equals(other.FloatField)) return false;
+      if (!Int64Field.Equals(other.Int64Field)) return false;
+      if (!Uint64Field.Equals(other.Uint64Field)) return false;
+      if (!Int32Field.Equals(other.Int32Field)) return false;
+      if (!Uint32Field.Equals(other.Uint32Field)) return false;
+      if (!BoolField.Equals(other.BoolField)) return false;
+      if (!StringField.Equals(other.StringField)) return false;
+      if (!BytesField.Equals(other.BytesField)) return false;
+      return true;
+    }
+
+    public override int GetHashCode() {
+      int hash = 1;
+      hash ^= AnyField.GetHashCode();
+      hash ^= ApiField.GetHashCode();
+      hash ^= DurationField.GetHashCode();
+      hash ^= EmptyField.GetHashCode();
+      hash ^= FieldMaskField.GetHashCode();
+      hash ^= SourceContextField.GetHashCode();
+      hash ^= StructField.GetHashCode();
+      hash ^= TimestampField.GetHashCode();
+      hash ^= TypeField.GetHashCode();
+      hash ^= DoubleField.GetHashCode();
+      hash ^= FloatField.GetHashCode();
+      hash ^= Int64Field.GetHashCode();
+      hash ^= Uint64Field.GetHashCode();
+      hash ^= Int32Field.GetHashCode();
+      hash ^= Uint32Field.GetHashCode();
+      hash ^= BoolField.GetHashCode();
+      hash ^= StringField.GetHashCode();
+      hash ^= BytesField.GetHashCode();
+      return hash;
+    }
+
+    public override string ToString() {
+      return pb::JsonFormatter.Default.Format(this);
+    }
+
+    public void WriteTo(pb::CodedOutputStream output) {
+      anyField_.WriteTo(output, _map_anyField_codec);
+      apiField_.WriteTo(output, _map_apiField_codec);
+      durationField_.WriteTo(output, _map_durationField_codec);
+      emptyField_.WriteTo(output, _map_emptyField_codec);
+      fieldMaskField_.WriteTo(output, _map_fieldMaskField_codec);
+      sourceContextField_.WriteTo(output, _map_sourceContextField_codec);
+      structField_.WriteTo(output, _map_structField_codec);
+      timestampField_.WriteTo(output, _map_timestampField_codec);
+      typeField_.WriteTo(output, _map_typeField_codec);
+      doubleField_.WriteTo(output, _map_doubleField_codec);
+      floatField_.WriteTo(output, _map_floatField_codec);
+      int64Field_.WriteTo(output, _map_int64Field_codec);
+      uint64Field_.WriteTo(output, _map_uint64Field_codec);
+      int32Field_.WriteTo(output, _map_int32Field_codec);
+      uint32Field_.WriteTo(output, _map_uint32Field_codec);
+      boolField_.WriteTo(output, _map_boolField_codec);
+      stringField_.WriteTo(output, _map_stringField_codec);
+      bytesField_.WriteTo(output, _map_bytesField_codec);
+    }
+
+    public int CalculateSize() {
+      int size = 0;
+      size += anyField_.CalculateSize(_map_anyField_codec);
+      size += apiField_.CalculateSize(_map_apiField_codec);
+      size += durationField_.CalculateSize(_map_durationField_codec);
+      size += emptyField_.CalculateSize(_map_emptyField_codec);
+      size += fieldMaskField_.CalculateSize(_map_fieldMaskField_codec);
+      size += sourceContextField_.CalculateSize(_map_sourceContextField_codec);
+      size += structField_.CalculateSize(_map_structField_codec);
+      size += timestampField_.CalculateSize(_map_timestampField_codec);
+      size += typeField_.CalculateSize(_map_typeField_codec);
+      size += doubleField_.CalculateSize(_map_doubleField_codec);
+      size += floatField_.CalculateSize(_map_floatField_codec);
+      size += int64Field_.CalculateSize(_map_int64Field_codec);
+      size += uint64Field_.CalculateSize(_map_uint64Field_codec);
+      size += int32Field_.CalculateSize(_map_int32Field_codec);
+      size += uint32Field_.CalculateSize(_map_uint32Field_codec);
+      size += boolField_.CalculateSize(_map_boolField_codec);
+      size += stringField_.CalculateSize(_map_stringField_codec);
+      size += bytesField_.CalculateSize(_map_bytesField_codec);
+      return size;
+    }
+
+    public void MergeFrom(MapWellKnownTypes other) {
+      if (other == null) {
+        return;
+      }
+      anyField_.Add(other.anyField_);
+      apiField_.Add(other.apiField_);
+      durationField_.Add(other.durationField_);
+      emptyField_.Add(other.emptyField_);
+      fieldMaskField_.Add(other.fieldMaskField_);
+      sourceContextField_.Add(other.sourceContextField_);
+      structField_.Add(other.structField_);
+      timestampField_.Add(other.timestampField_);
+      typeField_.Add(other.typeField_);
+      doubleField_.Add(other.doubleField_);
+      floatField_.Add(other.floatField_);
+      int64Field_.Add(other.int64Field_);
+      uint64Field_.Add(other.uint64Field_);
+      int32Field_.Add(other.int32Field_);
+      uint32Field_.Add(other.uint32Field_);
+      boolField_.Add(other.boolField_);
+      stringField_.Add(other.stringField_);
+      bytesField_.Add(other.bytesField_);
+    }
+
+    public void MergeFrom(pb::CodedInputStream input) {
+      uint tag;
+      while (input.ReadTag(out tag)) {
+        switch(tag) {
+          case 0:
+            throw pb::InvalidProtocolBufferException.InvalidTag();
+          default:
+            if (pb::WireFormat.IsEndGroupTag(tag)) {
+              return;
+            }
+            break;
+          case 10: {
+            anyField_.AddEntriesFrom(input, _map_anyField_codec);
+            break;
+          }
+          case 18: {
+            apiField_.AddEntriesFrom(input, _map_apiField_codec);
+            break;
+          }
+          case 26: {
+            durationField_.AddEntriesFrom(input, _map_durationField_codec);
+            break;
+          }
+          case 34: {
+            emptyField_.AddEntriesFrom(input, _map_emptyField_codec);
+            break;
+          }
+          case 42: {
+            fieldMaskField_.AddEntriesFrom(input, _map_fieldMaskField_codec);
+            break;
+          }
+          case 50: {
+            sourceContextField_.AddEntriesFrom(input, _map_sourceContextField_codec);
+            break;
+          }
+          case 58: {
+            structField_.AddEntriesFrom(input, _map_structField_codec);
+            break;
+          }
+          case 66: {
+            timestampField_.AddEntriesFrom(input, _map_timestampField_codec);
+            break;
+          }
+          case 74: {
+            typeField_.AddEntriesFrom(input, _map_typeField_codec);
+            break;
+          }
+          case 82: {
+            doubleField_.AddEntriesFrom(input, _map_doubleField_codec);
+            break;
+          }
+          case 90: {
+            floatField_.AddEntriesFrom(input, _map_floatField_codec);
+            break;
+          }
+          case 98: {
+            int64Field_.AddEntriesFrom(input, _map_int64Field_codec);
+            break;
+          }
+          case 106: {
+            uint64Field_.AddEntriesFrom(input, _map_uint64Field_codec);
+            break;
+          }
+          case 114: {
+            int32Field_.AddEntriesFrom(input, _map_int32Field_codec);
+            break;
+          }
+          case 122: {
+            uint32Field_.AddEntriesFrom(input, _map_uint32Field_codec);
+            break;
+          }
+          case 130: {
+            boolField_.AddEntriesFrom(input, _map_boolField_codec);
+            break;
+          }
+          case 138: {
+            stringField_.AddEntriesFrom(input, _map_stringField_codec);
+            break;
+          }
+          case 146: {
+            bytesField_.AddEntriesFrom(input, _map_bytesField_codec);
+            break;
+          }
+        }
+      }
+    }
+
+  }
+
+  #endregion
+
+}
+
+#endregion Designer generated code
diff --git a/csharp/src/ProtocolBuffers.Test/WellKnownTypes/WrappersTest.cs b/csharp/src/ProtocolBuffers.Test/WellKnownTypes/WrappersTest.cs
new file mode 100644
index 00000000..ad88c4eb
--- /dev/null
+++ b/csharp/src/ProtocolBuffers.Test/WellKnownTypes/WrappersTest.cs
@@ -0,0 +1,326 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+
+using System;
+using Google.Protobuf.TestProtos;
+using NUnit.Framework;
+using System.Collections;
+using System.IO;
+
+namespace Google.Protobuf.WellKnownTypes
+{
+    public class WrappersTest
+    {
+        [Test]
+        public void NullIsDefault()
+        {
+            var message = new TestWellKnownTypes();
+            Assert.IsNull(message.StringField);
+            Assert.IsNull(message.BytesField);
+            Assert.IsNull(message.BoolField);
+            Assert.IsNull(message.FloatField);
+            Assert.IsNull(message.DoubleField);
+            Assert.IsNull(message.Int32Field);
+            Assert.IsNull(message.Int64Field);
+            Assert.IsNull(message.Uint32Field);
+            Assert.IsNull(message.Uint64Field);
+        }
+
+        [Test]
+        public void NonDefaultSingleValues()
+        {
+            var message = new TestWellKnownTypes
+            {
+                StringField = "x",
+                BytesField = ByteString.CopyFrom(1, 2, 3),
+                BoolField = true,
+                FloatField = 12.5f,
+                DoubleField = 12.25d,
+                Int32Field = 1,
+                Int64Field = 2,
+                Uint32Field = 3,
+                Uint64Field = 4
+            };
+
+            var bytes = message.ToByteArray();
+            var parsed = TestWellKnownTypes.Parser.ParseFrom(bytes);
+
+            Assert.AreEqual("x", parsed.StringField);
+            Assert.AreEqual(ByteString.CopyFrom(1, 2, 3), parsed.BytesField);
+            Assert.AreEqual(true, parsed.BoolField);
+            Assert.AreEqual(12.5f, parsed.FloatField);
+            Assert.AreEqual(12.25d, parsed.DoubleField);
+            Assert.AreEqual(1, parsed.Int32Field);
+            Assert.AreEqual(2L, parsed.Int64Field);
+            Assert.AreEqual(3U, parsed.Uint32Field);
+            Assert.AreEqual(4UL, parsed.Uint64Field);
+        }
+
+        [Test]
+        public void NonNullDefaultIsPreservedThroughSerialization()
+        {
+            var message = new TestWellKnownTypes
+            {
+                StringField = "",
+                BytesField = ByteString.Empty,
+                BoolField = false,
+                FloatField = 0f,
+                DoubleField = 0d,
+                Int32Field = 0,
+                Int64Field = 0,
+                Uint32Field = 0,
+                Uint64Field = 0
+            };
+
+            var bytes = message.ToByteArray();
+            var parsed = TestWellKnownTypes.Parser.ParseFrom(bytes);
+
+            Assert.AreEqual("", parsed.StringField);
+            Assert.AreEqual(ByteString.Empty, parsed.BytesField);
+            Assert.AreEqual(false, parsed.BoolField);
+            Assert.AreEqual(0f, parsed.FloatField);
+            Assert.AreEqual(0d, parsed.DoubleField);
+            Assert.AreEqual(0, parsed.Int32Field);
+            Assert.AreEqual(0L, parsed.Int64Field);
+            Assert.AreEqual(0U, parsed.Uint32Field);
+            Assert.AreEqual(0UL, parsed.Uint64Field);
+        }
+
+        [Test]
+        public void RepeatedWrappersProhibitNullItems()
+        {
+            var message = new RepeatedWellKnownTypes();
+            Assert.Throws<ArgumentNullException>(() => message.BoolField.Add((bool?) null));
+            Assert.Throws<ArgumentNullException>(() => message.Int32Field.Add((int?) null));
+            Assert.Throws<ArgumentNullException>(() => message.StringField.Add((string) null));
+            Assert.Throws<ArgumentNullException>(() => message.BytesField.Add((ByteString) null));
+        }
+
+        [Test]
+        public void RepeatedWrappersSerializeDeserialize()
+        {
+            var message = new RepeatedWellKnownTypes
+            {
+                BoolField = { true, false },
+                BytesField = { ByteString.CopyFrom(1, 2, 3), ByteString.CopyFrom(4, 5, 6), ByteString.Empty },
+                DoubleField = { 12.5, -1.5, 0d },
+                FloatField = { 123.25f, -20f, 0f },
+                Int32Field = { int.MaxValue, int.MinValue, 0 },
+                Int64Field = { long.MaxValue, long.MinValue, 0L },                
+                StringField = { "First", "Second", "" },
+                Uint32Field = { uint.MaxValue, uint.MinValue, 0U },
+                Uint64Field = { ulong.MaxValue, ulong.MinValue, 0UL },
+            };
+            var bytes = message.ToByteArray();
+            var parsed = RepeatedWellKnownTypes.Parser.ParseFrom(bytes);
+
+            Assert.AreEqual(message, parsed);
+            // Just to test a single value for sanity...
+            Assert.AreEqual("Second", message.StringField[1]);
+        }
+
+        [Test]
+        public void MapWrappersSerializeDeserialize()
+        {
+            var message = new MapWellKnownTypes
+            {
+                BoolField = { { 10, false }, { 20, true } },
+                BytesField = {
+                    { -1, ByteString.CopyFrom(1, 2, 3) },
+                    { 10, ByteString.CopyFrom(4, 5, 6) },
+                    { 1000, ByteString.Empty },
+                    { 10000, null }
+                },
+                DoubleField = { { 1, 12.5 }, { 10, -1.5 }, { 20, 0d } },
+                FloatField = { { 2, 123.25f }, { 3, -20f }, { 4, 0f } },
+                Int32Field = { { 5, int.MaxValue }, { 6, int.MinValue }, { 7, 0 } },
+                Int64Field = { { 8, long.MaxValue }, { 9, long.MinValue }, { 10, 0L } },
+                StringField = { { 11, "First" }, { 12, "Second" }, { 13, "" }, { 14, null } },
+                Uint32Field = { { 15, uint.MaxValue }, { 16, uint.MinValue }, { 17, 0U } },
+                Uint64Field = { { 18, ulong.MaxValue }, { 19, ulong.MinValue }, { 20, 0UL } },
+            };
+
+            var bytes = message.ToByteArray();
+            var parsed = MapWellKnownTypes.Parser.ParseFrom(bytes);
+
+            Assert.AreEqual(message, parsed);
+            // Just to test a single value for sanity...
+            Assert.AreEqual("Second", message.StringField[12]);
+        }
+
+        [Test]
+        public void Reflection_SingleValues()
+        {
+            var message = new TestWellKnownTypes
+            {
+                StringField = "x",
+                BytesField = ByteString.CopyFrom(1, 2, 3),
+                BoolField = true,
+                FloatField = 12.5f,
+                DoubleField = 12.25d,
+                Int32Field = 1,
+                Int64Field = 2,
+                Uint32Field = 3,
+                Uint64Field = 4
+            };
+            var fields = ((IReflectedMessage) message).Fields;
+
+            Assert.AreEqual("x", fields[TestWellKnownTypes.StringFieldFieldNumber].GetValue(message));
+            Assert.AreEqual(ByteString.CopyFrom(1, 2, 3), fields[TestWellKnownTypes.BytesFieldFieldNumber].GetValue(message));
+            Assert.AreEqual(true, fields[TestWellKnownTypes.BoolFieldFieldNumber].GetValue(message));
+            Assert.AreEqual(12.5f, fields[TestWellKnownTypes.FloatFieldFieldNumber].GetValue(message));
+            Assert.AreEqual(12.25d, fields[TestWellKnownTypes.DoubleFieldFieldNumber].GetValue(message));
+            Assert.AreEqual(1, fields[TestWellKnownTypes.Int32FieldFieldNumber].GetValue(message));
+            Assert.AreEqual(2L, fields[TestWellKnownTypes.Int64FieldFieldNumber].GetValue(message));
+            Assert.AreEqual(3U, fields[TestWellKnownTypes.Uint32FieldFieldNumber].GetValue(message));
+            Assert.AreEqual(4UL, fields[TestWellKnownTypes.Uint64FieldFieldNumber].GetValue(message));
+
+            // And a couple of null fields...
+            message.StringField = null;
+            message.FloatField = null;
+            Assert.IsNull(fields[TestWellKnownTypes.StringFieldFieldNumber].GetValue(message));
+            Assert.IsNull(fields[TestWellKnownTypes.FloatFieldFieldNumber].GetValue(message));
+        }
+
+        [Test]
+        public void Reflection_RepeatedFields()
+        {
+            // Just a single example... note that we can't have a null value here
+            var message = new RepeatedWellKnownTypes { Int32Field = { 1, 2 } };
+            var fields = ((IReflectedMessage) message).Fields;
+            var list = (IList) fields[RepeatedWellKnownTypes.Int32FieldFieldNumber].GetValue(message);
+            CollectionAssert.AreEqual(new[] { 1, 2 }, list);
+        }
+
+        [Test]
+        public void Reflection_MapFields()
+        {
+            // Just a single example... note that we can't have a null value here
+            var message = new MapWellKnownTypes { Int32Field = { { 1, 2 }, { 3, null } } };
+            var fields = ((IReflectedMessage) message).Fields;
+            var dictionary = (IDictionary) fields[MapWellKnownTypes.Int32FieldFieldNumber].GetValue(message);
+            Assert.AreEqual(2, dictionary[1]);
+            Assert.IsNull(dictionary[3]);
+            Assert.IsTrue(dictionary.Contains(3));
+        }
+
+        [Test]
+        public void Oneof()
+        {
+            var message = new OneofWellKnownTypes { EmptyField = new Empty() };
+            // Start off with a non-wrapper
+            Assert.AreEqual(OneofWellKnownTypes.OneofFieldOneofCase.EmptyField, message.OneofFieldCase);
+            AssertOneofRoundTrip(message);
+
+            message.StringField = "foo";
+            Assert.AreEqual(OneofWellKnownTypes.OneofFieldOneofCase.StringField, message.OneofFieldCase);
+            AssertOneofRoundTrip(message);
+
+            message.StringField = "foo";
+            Assert.AreEqual(OneofWellKnownTypes.OneofFieldOneofCase.StringField, message.OneofFieldCase);
+            AssertOneofRoundTrip(message);
+
+            message.DoubleField = 0.0f;
+            Assert.AreEqual(OneofWellKnownTypes.OneofFieldOneofCase.DoubleField, message.OneofFieldCase);
+            AssertOneofRoundTrip(message);
+
+            message.DoubleField = 1.0f;
+            Assert.AreEqual(OneofWellKnownTypes.OneofFieldOneofCase.DoubleField, message.OneofFieldCase);
+            AssertOneofRoundTrip(message);
+
+            message.ClearOneofField();
+            Assert.AreEqual(OneofWellKnownTypes.OneofFieldOneofCase.None, message.OneofFieldCase);
+            AssertOneofRoundTrip(message);
+        }
+
+        private void AssertOneofRoundTrip(OneofWellKnownTypes message)
+        {
+            // Normal roundtrip, but explicitly checking the case...
+            var bytes = message.ToByteArray();
+            var parsed = OneofWellKnownTypes.Parser.ParseFrom(bytes);
+            Assert.AreEqual(message, parsed);
+            Assert.AreEqual(message.OneofFieldCase, parsed.OneofFieldCase);
+        }
+
+        [Test]
+        [TestCase("x", "y", "y")]
+        [TestCase("x", "", "x")]
+        [TestCase("x", null, "x")]
+        [TestCase("", "y", "y")]
+        [TestCase("", "", "")]
+        [TestCase("", null, "")]
+        [TestCase(null, "y", "y")]
+        [TestCase(null, "", "")]
+        [TestCase(null, null, null)]
+        public void Merging(string original, string merged, string expected)
+        {
+            var originalMessage = new TestWellKnownTypes { StringField = original };
+            var mergingMessage = new TestWellKnownTypes { StringField = merged };
+            originalMessage.MergeFrom(mergingMessage);
+            Assert.AreEqual(expected, originalMessage.StringField);
+
+            // Try it using MergeFrom(CodedInputStream) too...
+            originalMessage = new TestWellKnownTypes { StringField = original };
+            originalMessage.MergeFrom(mergingMessage.ToByteArray());
+            Assert.AreEqual(expected, originalMessage.StringField);
+        }
+
+        // Merging is odd with wrapper types, due to the way that default values aren't emitted in
+        // the binary stream. In fact we cheat a little bit - a message with an explicitly present default
+        // value will have that default value ignored.
+        [Test]
+        public void MergingCornerCase()
+        {
+            var message = new TestWellKnownTypes { Int32Field = 5 };
+
+            // Create a byte array which has the data of an Int32Value explicitly containing a value of 0.
+            // This wouldn't normally happen.
+            byte[] bytes;
+            var wrapperTag = WireFormat.MakeTag(TestWellKnownTypes.Int32FieldFieldNumber, WireFormat.WireType.LengthDelimited);
+            var valueTag = WireFormat.MakeTag(Int32Value.ValueFieldNumber, WireFormat.WireType.Varint);
+            using (var stream = new MemoryStream())
+            {
+                var coded = CodedOutputStream.CreateInstance(stream);
+                coded.WriteTag(wrapperTag);
+                coded.WriteLength(2); // valueTag + a value 0, each one byte
+                coded.WriteTag(valueTag);
+                coded.WriteInt32(0);
+                coded.Flush();
+                bytes = stream.ToArray();
+            }
+
+            message.MergeFrom(bytes);
+            // A normal implementation would have 0 now, as the explicit default would have been overwritten the 5.
+            Assert.AreEqual(5, message.Int32Field);
+        }
+    }
+}
diff --git a/csharp/src/ProtocolBuffers/ByteString.cs b/csharp/src/ProtocolBuffers/ByteString.cs
index 738f020e..329f47f6 100644
--- a/csharp/src/ProtocolBuffers/ByteString.cs
+++ b/csharp/src/ProtocolBuffers/ByteString.cs
@@ -212,11 +212,22 @@ namespace Google.Protobuf
             {

                 return true;

             }

-            if (ReferenceEquals(lhs, null))

+            if (ReferenceEquals(lhs, null) || ReferenceEquals(rhs, null))

             {

                 return false;

             }

-            return lhs.Equals(rhs);

+            if (lhs.bytes.Length != rhs.bytes.Length)

+            {

+                return false;

+            }

+            for (int i = 0; i < lhs.Length; i++)

+            {

+                if (rhs.bytes[i] != lhs.bytes[i])

+                {

+                    return false;

+                }

+            }

+            return true;

         }

 

         public static bool operator !=(ByteString lhs, ByteString rhs)

@@ -228,12 +239,7 @@ namespace Google.Protobuf
 

         public override bool Equals(object obj)

         {

-            ByteString other = obj as ByteString;

-            if (obj == null)

-            {

-                return false;

-            }

-            return Equals(other);

+            return this == (obj as ByteString);

         }

 

         public override int GetHashCode()

@@ -248,18 +254,7 @@ namespace Google.Protobuf
 

         public bool Equals(ByteString other)

         {

-            if (other.bytes.Length != bytes.Length)

-            {

-                return false;

-            }

-            for (int i = 0; i < bytes.Length; i++)

-            {

-                if (other.bytes[i] != bytes[i])

-                {

-                    return false;

-                }

-            }

-            return true;

+            return this == other;

         }

 

         /// <summary>

diff --git a/csharp/src/ProtocolBuffers/CodedOutputStream.ComputeSize.cs b/csharp/src/ProtocolBuffers/CodedOutputStream.ComputeSize.cs
index a3e7c1bb..bf221c9c 100644
--- a/csharp/src/ProtocolBuffers/CodedOutputStream.ComputeSize.cs
+++ b/csharp/src/ProtocolBuffers/CodedOutputStream.ComputeSize.cs
@@ -129,8 +129,7 @@ namespace Google.Protobuf
         public static int ComputeStringSize(String value)

         {

             int byteArraySize = Utf8Encoding.GetByteCount(value);

-            return ComputeRawVarint32Size((uint) byteArraySize) +

-                   byteArraySize;

+            return ComputeLengthSize(byteArraySize) + byteArraySize;

         }

 

         /// <summary>

@@ -149,7 +148,7 @@ namespace Google.Protobuf
         public static int ComputeMessageSize(IMessage value)

         {

             int size = value.CalculateSize();

-            return ComputeRawVarint32Size((uint) size) + size;

+            return ComputeLengthSize(size) + size;

         }

 

         /// <summary>

@@ -158,8 +157,7 @@ namespace Google.Protobuf
         /// </summary>

         public static int ComputeBytesSize(ByteString value)

         {

-            return ComputeRawVarint32Size((uint) value.Length) +

-                   value.Length;

+            return ComputeLengthSize(value.Length) + value.Length;

         }

 

         /// <summary>

diff --git a/csharp/src/ProtocolBuffers/CodedOutputStream.cs b/csharp/src/ProtocolBuffers/CodedOutputStream.cs
index 53f04c77..b91d6d70 100644
--- a/csharp/src/ProtocolBuffers/CodedOutputStream.cs
+++ b/csharp/src/ProtocolBuffers/CodedOutputStream.cs
@@ -274,7 +274,7 @@ namespace Google.Protobuf
         /// <param name="value">The value to write</param>

         public void WriteMessage(IMessage value)

         {

-            WriteRawVarint32((uint) value.CalculateSize());

+            WriteLength(value.CalculateSize());

             value.WriteTo(this);

         }

 

@@ -285,7 +285,7 @@ namespace Google.Protobuf
         /// <param name="value">The value to write</param>

         public void WriteBytes(ByteString value)

         {

-            WriteRawVarint32((uint) value.Length);

+            WriteLength(value.Length);

             value.WriteRawBytesTo(this);

         }

 

diff --git a/csharp/src/ProtocolBuffers/Collections/MapField.cs b/csharp/src/ProtocolBuffers/Collections/MapField.cs
index 0f379eaa..f5e4fd3a 100644
--- a/csharp/src/ProtocolBuffers/Collections/MapField.cs
+++ b/csharp/src/ProtocolBuffers/Collections/MapField.cs
@@ -51,14 +51,38 @@ namespace Google.Protobuf.Collections
     public sealed class MapField<TKey, TValue> : IDeepCloneable<MapField<TKey, TValue>>, IFreezable, IDictionary<TKey, TValue>, IEquatable<MapField<TKey, TValue>>, IDictionary
     {
         // TODO: Don't create the map/list until we have an entry. (Assume many maps will be empty.)
+        private readonly bool allowNullValues;
         private bool frozen;
         private readonly Dictionary<TKey, LinkedListNode<KeyValuePair<TKey, TValue>>> map =
             new Dictionary<TKey, LinkedListNode<KeyValuePair<TKey, TValue>>>();
         private readonly LinkedList<KeyValuePair<TKey, TValue>> list = new LinkedList<KeyValuePair<TKey, TValue>>();
 
+        /// <summary>
+        /// Constructs a new map field, defaulting the value nullability to only allow null values for message types
+        /// and non-nullable value types.
+        /// </summary>
+        public MapField() : this(typeof(IMessage).IsAssignableFrom(typeof(TValue)) || Nullable.GetUnderlyingType(typeof(TValue)) != null)
+        {
+        }
+
+        /// <summary>
+        /// Constructs a new map field, overriding the choice of whether null values are permitted in the map.
+        /// This is used by wrapper types, where maps with string and bytes wrappers as the value types
+        /// support null values.
+        /// </summary>
+        /// <param name="allowNullValues">Whether null values are permitted in the map or not.</param>
+        public MapField(bool allowNullValues)
+        {
+            if (allowNullValues && typeof(TValue).IsValueType && Nullable.GetUnderlyingType(typeof(TValue)) == null)
+            {
+                throw new ArgumentException("allowNullValues", "Non-nullable value types do not support null values");
+            }
+            this.allowNullValues = allowNullValues;
+        }
+
         public MapField<TKey, TValue> Clone()
         {
-            var clone = new MapField<TKey, TValue>();
+            var clone = new MapField<TKey, TValue>(allowNullValues);
             // Keys are never cloneable. Values might be.
             if (typeof(IDeepCloneable<TValue>).IsAssignableFrom(typeof(TValue)))
             {
@@ -138,7 +162,8 @@ namespace Google.Protobuf.Collections
             set
             {
                 ThrowHelper.ThrowIfNull(key, "key");
-                if (value == null && (typeof(TValue) == typeof(ByteString) || typeof(TValue) == typeof(string)))
+                // value == null check here is redundant, but avoids boxing.
+                if (value == null && !allowNullValues)
                 {
                     ThrowHelper.ThrowIfNull(value, "value");
                 }
@@ -225,6 +250,11 @@ namespace Google.Protobuf.Collections
             }
         }
 
+        /// <summary>
+        /// Returns whether or not this map allows values to be null.
+        /// </summary>
+        public bool AllowsNullValues { get { return allowNullValues; } }
+
         public int Count { get { return list.Count; } }
         public bool IsReadOnly { get { return frozen; } }
 
diff --git a/csharp/src/ProtocolBuffers/Collections/RepeatedField.cs b/csharp/src/ProtocolBuffers/Collections/RepeatedField.cs
index 8375ae0b..9bab41ea 100644
--- a/csharp/src/ProtocolBuffers/Collections/RepeatedField.cs
+++ b/csharp/src/ProtocolBuffers/Collections/RepeatedField.cs
@@ -123,7 +123,7 @@ namespace Google.Protobuf.Collections
             {
                 int dataSize = CalculatePackedDataSize(codec);
                 return CodedOutputStream.ComputeRawVarint32Size(tag) +
-                    CodedOutputStream.ComputeRawVarint32Size((uint)dataSize) +
+                    CodedOutputStream.ComputeLengthSize(dataSize) +
                     dataSize;
             }
             else
diff --git a/csharp/src/ProtocolBuffers/FieldCodec.cs b/csharp/src/ProtocolBuffers/FieldCodec.cs
index c72a3e7b..85462787 100644
--- a/csharp/src/ProtocolBuffers/FieldCodec.cs
+++ b/csharp/src/ProtocolBuffers/FieldCodec.cs
@@ -29,7 +29,7 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endregion
-    
+
 using System;
 using System.Collections.Generic;
 
@@ -43,7 +43,7 @@ namespace Google.Protobuf
         // TODO: Avoid the "dual hit" of lambda expressions: create open delegates instead. (At least test...)
         public static FieldCodec<string> ForString(uint tag)
         {
-            return new FieldCodec<string>(input => input.ReadString(), (output, value) => output.WriteString(value), CodedOutputStream.ComputeStringSize, tag); 
+            return new FieldCodec<string>(input => input.ReadString(), (output, value) => output.WriteString(value), CodedOutputStream.ComputeStringSize, tag);
         }
 
         public static FieldCodec<ByteString> ForBytes(uint tag)
@@ -131,6 +131,116 @@ namespace Google.Protobuf
             return new FieldCodec<T>(input => { T message = parser.CreateTemplate(); input.ReadMessage(message); return message; },
                 (output, value) => output.WriteMessage(value), message => CodedOutputStream.ComputeMessageSize(message), tag);
         }
+
+        /// <summary>
+        /// Creates a codec for a wrapper type of a class - which must be string or ByteString.
+        /// </summary>
+        public static FieldCodec<T> ForClassWrapper<T>(uint tag) where T : class
+        {
+            var nestedCodec = WrapperCodecs.GetCodec<T>();
+            return new FieldCodec<T>(
+                input => WrapperCodecs.Read<T>(input, nestedCodec),
+                (output, value) => WrapperCodecs.Write<T>(output, value, nestedCodec),
+                value => WrapperCodecs.CalculateSize<T>(value, nestedCodec),
+                tag,
+                null); // Default value for the wrapper
+        }
+
+        /// <summary>
+        /// Creates a codec for a wrapper type of a struct - which must be Int32, Int64, UInt32, UInt64,
+        /// Bool, Single or Double.
+        /// </summary>
+        public static FieldCodec<T?> ForStructWrapper<T>(uint tag) where T : struct
+        {
+            var nestedCodec = WrapperCodecs.GetCodec<T>();
+            return new FieldCodec<T?>(
+                input => WrapperCodecs.Read<T>(input, nestedCodec),
+                (output, value) => WrapperCodecs.Write<T>(output, value.Value, nestedCodec),
+                value => value == null ? 0 : WrapperCodecs.CalculateSize<T>(value.Value, nestedCodec),
+                tag,
+                null); // Default value for the wrapper
+        }
+
+        /// <summary>
+        /// Helper code to create codecs for wrapper types.
+        /// </summary>
+        /// <remarks>
+        /// Somewhat ugly with all the static methods, but the conversions involved to/from nullable types make it
+        /// slightly tricky to improve. So long as we keep the public API (ForClassWrapper, ForStructWrapper) in place,
+        /// we can refactor later if we come up with something cleaner.
+        /// </remarks>
+        private static class WrapperCodecs
+        {
+            // All the field numbers are the same (1).
+            private const int WrapperValueFieldNumber = Google.Protobuf.WellKnownTypes.Int32Value.ValueFieldNumber;
+
+            private static readonly Dictionary<Type, object> Codecs = new Dictionary<Type, object>
+            {
+                { typeof(bool), ForBool(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Varint)) },
+                { typeof(int), ForInt32(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Varint)) },
+                { typeof(long), ForInt64(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Varint)) },
+                { typeof(uint), ForUInt32(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Varint)) },
+                { typeof(ulong), ForUInt64(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Varint)) },
+                { typeof(float), ForFloat(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Fixed32)) },
+                { typeof(double), ForDouble(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Fixed64)) },
+                { typeof(string), ForString(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.LengthDelimited)) },
+                { typeof(ByteString), ForBytes(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.LengthDelimited)) }
+            };
+
+            /// <summary>
+            /// Returns a field codec which effectively wraps a value of type T in a message.
+            /// 
+            /// </summary>
+            internal static FieldCodec<T> GetCodec<T>()
+            {
+                object value;
+                if (!Codecs.TryGetValue(typeof(T), out value))
+                {
+                    throw new InvalidOperationException("Invalid type argument requested for wrapper codec: " + typeof(T));
+                }
+                return (FieldCodec<T>) value;
+            }
+
+            internal static T Read<T>(CodedInputStream input, FieldCodec<T> codec)
+            {
+                int length = input.ReadLength();
+                int oldLimit = input.PushLimit(length);
+
+                uint tag;
+                T value = codec.DefaultValue;
+                while (input.ReadTag(out tag))
+                {
+                    if (tag == 0)
+                    {
+                        throw InvalidProtocolBufferException.InvalidTag();
+                    }
+                    if (tag == codec.Tag)
+                    {
+                        value = codec.Read(input);
+                    }
+                    if (WireFormat.IsEndGroupTag(tag))
+                    {
+                        break;
+                    }
+                }
+                input.CheckLastTagWas(0);
+                input.PopLimit(oldLimit);
+
+                return value;
+            }
+
+            internal static void Write<T>(CodedOutputStream output, T value, FieldCodec<T> codec)
+            {
+                output.WriteLength(codec.CalculateSizeWithTag(value));
+                codec.WriteTagAndValue(output, value);
+            }
+
+            internal  static int CalculateSize<T>(T value, FieldCodec<T> codec)
+            {
+                int fieldLength = codec.CalculateSizeWithTag(value);
+                return CodedOutputStream.ComputeLengthSize(fieldLength) + fieldLength;
+            }
+        }
     }
 
     /// <summary>
@@ -144,31 +254,19 @@ namespace Google.Protobuf
     /// </remarks>
     public sealed class FieldCodec<T>
     {
-        private static readonly Func<T, bool> IsDefault;
-        private static readonly T Default;
+        private static readonly T DefaultDefault;
 
         static FieldCodec()
         {
             if (typeof(T) == typeof(string))
             {
-                Default = (T)(object)"";
-                IsDefault = CreateDefaultValueCheck<string>(x => x.Length == 0);
+                DefaultDefault = (T)(object)"";
             }
             else if (typeof(T) == typeof(ByteString))
             {
-                Default = (T)(object)ByteString.Empty;
-                IsDefault = CreateDefaultValueCheck<ByteString>(x => x.Length == 0);
-            }
-            else if (!typeof(T).IsValueType)
-            {
-                // Default default
-                IsDefault = CreateDefaultValueCheck<T>(x => x == null);
-            }
-            else
-            {
-                // Default default
-                IsDefault = CreateDefaultValueCheck<T>(x => EqualityComparer<T>.Default.Equals(x, default(T)));
+                DefaultDefault = (T)(object)ByteString.Empty;
             }
+            // Otherwise it's the default value of the CLR type
         }
 
         private static Func<T, bool> CreateDefaultValueCheck<TTmp>(Func<TTmp, bool> check)
@@ -182,18 +280,32 @@ namespace Google.Protobuf
         private readonly uint tag;
         private readonly int tagSize;
         private readonly int fixedSize;
+        // Default value for this codec. Usually the same for every instance of the same type, but
+        // for string/ByteString wrapper fields the codec's default value is null, whereas for
+        // other string/ByteString fields it's "" or ByteString.Empty.
+        private readonly T defaultValue;
 
         internal FieldCodec(
             Func<CodedInputStream, T> reader,
             Action<CodedOutputStream, T> writer,
             Func<T, int> sizeCalculator,
-            uint tag)
+            uint tag) : this(reader, writer, sizeCalculator, tag, DefaultDefault)
+        {
+        }
+
+        internal FieldCodec(
+            Func<CodedInputStream, T> reader,
+            Action<CodedOutputStream, T> writer,
+            Func<T, int> sizeCalculator,
+            uint tag,
+            T defaultValue)
         {
             this.reader = reader;
             this.writer = writer;
             this.sizeCalculator = sizeCalculator;
             this.fixedSize = 0;
             this.tag = tag;
+            this.defaultValue = defaultValue;
             tagSize = CodedOutputStream.ComputeRawVarint32Size(tag);
         }
 
@@ -234,7 +346,7 @@ namespace Google.Protobuf
 
         public uint Tag { get { return tag; } }
 
-        public T DefaultValue { get { return Default; } }
+        public T DefaultValue { get { return defaultValue; } }
 
         /// <summary>
         /// Write a tag and the given value, *if* the value is not the default.
@@ -260,6 +372,11 @@ namespace Google.Protobuf
         public int CalculateSizeWithTag(T value)
         {
             return IsDefault(value) ? 0 : sizeCalculator(value) + tagSize;
-        }        
+        }
+
+        private bool IsDefault(T value)
+        {
+            return EqualityComparer<T>.Default.Equals(value, defaultValue);
+        }
     }
 }
diff --git a/src/Makefile.am b/src/Makefile.am
index 18e27772..865e78d2 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -442,7 +442,9 @@ libprotoc_la_SOURCES =                                         \
   google/protobuf/compiler/csharp/csharp_source_generator_base.cc \
   google/protobuf/compiler/csharp/csharp_source_generator_base.h \
   google/protobuf/compiler/csharp/csharp_umbrella_class.cc     \
-  google/protobuf/compiler/csharp/csharp_umbrella_class.h
+  google/protobuf/compiler/csharp/csharp_umbrella_class.h      \
+  google/protobuf/compiler/csharp/csharp_wrapper_field.cc      \
+  google/protobuf/compiler/csharp/csharp_wrapper_field.h
 
 bin_PROGRAMS = protoc
 protoc_LDADD = $(PTHREAD_LIBS) libprotobuf.la libprotoc.la
diff --git a/src/google/protobuf/compiler/csharp/csharp_field_base.cc b/src/google/protobuf/compiler/csharp/csharp_field_base.cc
index c9791c1d..89d4eb18 100644
--- a/src/google/protobuf/compiler/csharp/csharp_field_base.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_field_base.cc
@@ -169,6 +169,18 @@ std::string FieldGeneratorBase::type_name(const FieldDescriptor* descriptor) {
       return GetClassName(descriptor->enum_type());
     case FieldDescriptor::TYPE_MESSAGE:
     case FieldDescriptor::TYPE_GROUP:
+      if (IsWrapperType(descriptor)) {
+        const FieldDescriptor* wrapped_field = descriptor->message_type()->field(0);
+        string wrapped_field_type_name = type_name(wrapped_field);
+        // String and ByteString go to the same type; other wrapped types go to the
+        // nullable equivalent.
+        if (wrapped_field->type() == FieldDescriptor::TYPE_STRING ||
+            wrapped_field->type() == FieldDescriptor::TYPE_BYTES) {
+          return wrapped_field_type_name;
+        } else {
+          return wrapped_field_type_name + "?";
+        }
+      }
       return GetClassName(descriptor->message_type());
     case FieldDescriptor::TYPE_DOUBLE:
       return "double";
@@ -298,14 +310,23 @@ std::string FieldGeneratorBase::GetBytesDefaultValueInternal() {
 }
 
 std::string FieldGeneratorBase::default_value() {
-  switch (descriptor_->type()) {
+    return default_value(descriptor_);
+}
+
+std::string FieldGeneratorBase::default_value(const FieldDescriptor* descriptor) {
+  switch (descriptor->type()) {
     case FieldDescriptor::TYPE_ENUM:
-      return type_name() + "." + descriptor_->default_value_enum()->name();
+      return type_name() + "." + descriptor->default_value_enum()->name();
     case FieldDescriptor::TYPE_MESSAGE:
     case FieldDescriptor::TYPE_GROUP:
-      return type_name() + ".DefaultInstance";
+      if (IsWrapperType(descriptor)) {
+        const FieldDescriptor* wrapped_field = descriptor->message_type()->field(0);
+        return default_value(wrapped_field);
+      } else {
+        return "null";
+      }
     case FieldDescriptor::TYPE_DOUBLE: {
-      double value = descriptor_->default_value_double();
+      double value = descriptor->default_value_double();
       if (value == numeric_limits<double>::infinity()) {
         return "double.PositiveInfinity";
       } else if (value == -numeric_limits<double>::infinity()) {
@@ -316,7 +337,7 @@ std::string FieldGeneratorBase::default_value() {
       return SimpleDtoa(value) + "D";
     }
     case FieldDescriptor::TYPE_FLOAT: {
-      float value = descriptor_->default_value_float();
+      float value = descriptor->default_value_float();
       if (value == numeric_limits<float>::infinity()) {
         return "float.PositiveInfinity";
       } else if (value == -numeric_limits<float>::infinity()) {
@@ -327,17 +348,17 @@ std::string FieldGeneratorBase::default_value() {
       return SimpleFtoa(value) + "F";
     }
     case FieldDescriptor::TYPE_INT64:
-      return SimpleItoa(descriptor_->default_value_int64()) + "L";
+      return SimpleItoa(descriptor->default_value_int64()) + "L";
     case FieldDescriptor::TYPE_UINT64:
-      return SimpleItoa(descriptor_->default_value_uint64()) + "UL";
+      return SimpleItoa(descriptor->default_value_uint64()) + "UL";
     case FieldDescriptor::TYPE_INT32:
-      return SimpleItoa(descriptor_->default_value_int32());
+      return SimpleItoa(descriptor->default_value_int32());
     case FieldDescriptor::TYPE_FIXED64:
-      return SimpleItoa(descriptor_->default_value_uint64()) + "UL";
+      return SimpleItoa(descriptor->default_value_uint64()) + "UL";
     case FieldDescriptor::TYPE_FIXED32:
-      return SimpleItoa(descriptor_->default_value_uint32());
+      return SimpleItoa(descriptor->default_value_uint32());
     case FieldDescriptor::TYPE_BOOL:
-      if (descriptor_->default_value_bool()) {
+      if (descriptor->default_value_bool()) {
         return "true";
       } else {
         return "false";
@@ -347,15 +368,15 @@ std::string FieldGeneratorBase::default_value() {
     case FieldDescriptor::TYPE_BYTES:
       return GetBytesDefaultValueInternal();
     case FieldDescriptor::TYPE_UINT32:
-      return SimpleItoa(descriptor_->default_value_uint32());
+      return SimpleItoa(descriptor->default_value_uint32());
     case FieldDescriptor::TYPE_SFIXED32:
-      return SimpleItoa(descriptor_->default_value_int32());
+      return SimpleItoa(descriptor->default_value_int32());
     case FieldDescriptor::TYPE_SFIXED64:
-      return SimpleItoa(descriptor_->default_value_int64()) + "L";
+      return SimpleItoa(descriptor->default_value_int64()) + "L";
     case FieldDescriptor::TYPE_SINT32:
-      return SimpleItoa(descriptor_->default_value_int32());
+      return SimpleItoa(descriptor->default_value_int32());
     case FieldDescriptor::TYPE_SINT64:
-      return SimpleItoa(descriptor_->default_value_int64()) + "L";
+      return SimpleItoa(descriptor->default_value_int64()) + "L";
     default:
       GOOGLE_LOG(FATAL)<< "Unknown field type.";
       return "";
diff --git a/src/google/protobuf/compiler/csharp/csharp_field_base.h b/src/google/protobuf/compiler/csharp/csharp_field_base.h
index bffa2062..4761dc49 100644
--- a/src/google/protobuf/compiler/csharp/csharp_field_base.h
+++ b/src/google/protobuf/compiler/csharp/csharp_field_base.h
@@ -82,6 +82,7 @@ class FieldGeneratorBase : public SourceGeneratorBase {
   bool has_default_value();
   bool is_nullable_type();
   std::string default_value();
+  std::string default_value(const FieldDescriptor* descriptor);
   std::string number();
   std::string capitalized_type_name();
   std::string field_ordinal();
diff --git a/src/google/protobuf/compiler/csharp/csharp_helpers.cc b/src/google/protobuf/compiler/csharp/csharp_helpers.cc
index 8ecd1dc2..1c7a24a9 100644
--- a/src/google/protobuf/compiler/csharp/csharp_helpers.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_helpers.cc
@@ -52,6 +52,7 @@
 #include <google/protobuf/compiler/csharp/csharp_repeated_enum_field.h>
 #include <google/protobuf/compiler/csharp/csharp_repeated_message_field.h>
 #include <google/protobuf/compiler/csharp/csharp_repeated_primitive_field.h>
+#include <google/protobuf/compiler/csharp/csharp_wrapper_field.h>
 
 namespace google {
 namespace protobuf {
@@ -366,31 +367,39 @@ FieldGeneratorBase* CreateFieldGenerator(const FieldDescriptor* descriptor,
           return new RepeatedMessageFieldGenerator(descriptor, fieldOrdinal);
         }
       } else {
-	if (descriptor->containing_oneof()) {
-	  return new MessageOneofFieldGenerator(descriptor, fieldOrdinal);
-	} else {
-	  return new MessageFieldGenerator(descriptor, fieldOrdinal);
-	}
+        if (IsWrapperType(descriptor)) {
+          if (descriptor->containing_oneof()) {
+            return new WrapperOneofFieldGenerator(descriptor, fieldOrdinal);
+          } else {
+            return new WrapperFieldGenerator(descriptor, fieldOrdinal);
+          }
+        } else {
+          if (descriptor->containing_oneof()) {
+            return new MessageOneofFieldGenerator(descriptor, fieldOrdinal);
+          } else {
+            return new MessageFieldGenerator(descriptor, fieldOrdinal);
+          }
+        }
       }
     case FieldDescriptor::TYPE_ENUM:
       if (descriptor->is_repeated()) {
         return new RepeatedEnumFieldGenerator(descriptor, fieldOrdinal);
       } else {
-	if (descriptor->containing_oneof()) {
-	  return new EnumOneofFieldGenerator(descriptor, fieldOrdinal);
-	} else {
-	  return new EnumFieldGenerator(descriptor, fieldOrdinal);
-	}
+        if (descriptor->containing_oneof()) {
+          return new EnumOneofFieldGenerator(descriptor, fieldOrdinal);
+        } else {
+          return new EnumFieldGenerator(descriptor, fieldOrdinal);
+        }
       }
     default:
       if (descriptor->is_repeated()) {
         return new RepeatedPrimitiveFieldGenerator(descriptor, fieldOrdinal);
       } else {
-	if (descriptor->containing_oneof()) {
-	  return new PrimitiveOneofFieldGenerator(descriptor, fieldOrdinal);
-	} else {
-	  return new PrimitiveFieldGenerator(descriptor, fieldOrdinal);
-	}
+        if (descriptor->containing_oneof()) {
+          return new PrimitiveOneofFieldGenerator(descriptor, fieldOrdinal);
+        } else {
+          return new PrimitiveFieldGenerator(descriptor, fieldOrdinal);
+        }
       }
   }
 }
diff --git a/src/google/protobuf/compiler/csharp/csharp_helpers.h b/src/google/protobuf/compiler/csharp/csharp_helpers.h
index 111feabd..653ff992 100644
--- a/src/google/protobuf/compiler/csharp/csharp_helpers.h
+++ b/src/google/protobuf/compiler/csharp/csharp_helpers.h
@@ -119,6 +119,15 @@ inline bool IsDescriptorProto(const FileDescriptor* descriptor) {
   return descriptor->name() == "google/protobuf/descriptor_proto_file.proto";
 }
 
+inline bool IsMapEntry(const Descriptor* descriptor) {
+    return descriptor->options().map_entry();
+}
+
+inline bool IsWrapperType(const FieldDescriptor* descriptor) {
+  return descriptor->type() == FieldDescriptor::TYPE_MESSAGE &&
+      descriptor->message_type()->file()->name() == "google/protobuf/wrappers.proto";
+}
+
 }  // namespace csharp
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/csharp/csharp_map_field.cc b/src/google/protobuf/compiler/csharp/csharp_map_field.cc
index 32c05232..cba24a59 100644
--- a/src/google/protobuf/compiler/csharp/csharp_map_field.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_map_field.cc
@@ -61,6 +61,7 @@ void MapFieldGenerator::GenerateMembers(io::Printer* printer) {
       descriptor_->message_type()->FindFieldByName("value");
   variables_["key_type_name"] = type_name(key_descriptor);
   variables_["value_type_name"] = type_name(value_descriptor);
+  variables_["true_for_wrappers"] = IsWrapperType(value_descriptor) ? "true" : "";
   scoped_ptr<FieldGeneratorBase> key_generator(CreateFieldGenerator(key_descriptor, 1));  
   scoped_ptr<FieldGeneratorBase> value_generator(CreateFieldGenerator(value_descriptor, 2));
 
@@ -74,7 +75,7 @@ void MapFieldGenerator::GenerateMembers(io::Printer* printer) {
   printer->Print(
     variables_,
     ", $tag$);\n"
-    "private readonly pbc::MapField<$key_type_name$, $value_type_name$> $name$_ = new pbc::MapField<$key_type_name$, $value_type_name$>();\n");
+    "private readonly pbc::MapField<$key_type_name$, $value_type_name$> $name$_ = new pbc::MapField<$key_type_name$, $value_type_name$>($true_for_wrappers$);\n");
   AddDeprecatedFlag(printer);
   printer->Print(
     variables_,
diff --git a/src/google/protobuf/compiler/csharp/csharp_repeated_message_field.cc b/src/google/protobuf/compiler/csharp/csharp_repeated_message_field.cc
index 6d4e6984..d939fc79 100644
--- a/src/google/protobuf/compiler/csharp/csharp_repeated_message_field.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_repeated_message_field.cc
@@ -39,6 +39,8 @@
 
 #include <google/protobuf/compiler/csharp/csharp_helpers.h>
 #include <google/protobuf/compiler/csharp/csharp_repeated_message_field.h>
+#include <google/protobuf/compiler/csharp/csharp_message_field.h>
+#include <google/protobuf/compiler/csharp/csharp_wrapper_field.h>
 
 namespace google {
 namespace protobuf {
@@ -58,7 +60,18 @@ void RepeatedMessageFieldGenerator::GenerateMembers(io::Printer* printer) {
   printer->Print(
     variables_,
     "private static readonly pb::FieldCodec<$type_name$> _repeated_$name$_codec\n"
-    "    = pb::FieldCodec.ForMessage($tag$, $type_name$.Parser);\n");
+    "    = ");
+  // Don't want to duplicate the codec code here... maybe we should have a
+  // "create single field generator for this repeated field"
+  // function, but it doesn't seem worth it for just this.
+  if (IsWrapperType(descriptor_)) {
+    scoped_ptr<FieldGeneratorBase> single_generator(new WrapperFieldGenerator(descriptor_, fieldOrdinal_));
+    single_generator->GenerateCodecCode(printer);
+  } else {
+    scoped_ptr<FieldGeneratorBase> single_generator(new MessageFieldGenerator(descriptor_, fieldOrdinal_));
+    single_generator->GenerateCodecCode(printer);
+  }
+  printer->Print(";\n");
   printer->Print(
     variables_,
     "private readonly pbc::RepeatedField<$type_name$> $name$_ = new pbc::RepeatedField<$type_name$>();\n");
diff --git a/src/google/protobuf/compiler/csharp/csharp_wrapper_field.cc b/src/google/protobuf/compiler/csharp/csharp_wrapper_field.cc
new file mode 100644
index 00000000..75ef5e50
--- /dev/null
+++ b/src/google/protobuf/compiler/csharp/csharp_wrapper_field.cc
@@ -0,0 +1,209 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <sstream>
+
+#include <google/protobuf/compiler/code_generator.h>
+#include <google/protobuf/compiler/plugin.h>
+#include <google/protobuf/descriptor.h>
+#include <google/protobuf/descriptor.pb.h>
+#include <google/protobuf/io/printer.h>
+#include <google/protobuf/io/zero_copy_stream.h>
+
+#include <google/protobuf/compiler/csharp/csharp_helpers.h>
+#include <google/protobuf/compiler/csharp/csharp_wrapper_field.h>
+
+namespace google {
+namespace protobuf {
+namespace compiler {
+namespace csharp {
+
+WrapperFieldGenerator::WrapperFieldGenerator(const FieldDescriptor* descriptor,
+                                       int fieldOrdinal)
+    : FieldGeneratorBase(descriptor, fieldOrdinal) {
+  variables_["has_property_check"] = name() + "_ != null";
+  variables_["has_not_property_check"] = name() + "_ == null";
+  const FieldDescriptor* wrapped_field = descriptor->message_type()->field(0);
+  is_value_type = wrapped_field->type() != FieldDescriptor::TYPE_STRING &&
+      wrapped_field->type() != FieldDescriptor::TYPE_BYTES;
+  if (is_value_type) {
+    variables_["nonnullable_type_name"] = type_name(wrapped_field);
+  }
+}
+
+WrapperFieldGenerator::~WrapperFieldGenerator() {
+}
+
+void WrapperFieldGenerator::GenerateMembers(io::Printer* printer) {
+  printer->Print(
+        variables_,
+        "private static readonly pb::FieldCodec<$type_name$> _single_$name$_codec = ");
+  GenerateCodecCode(printer);
+  printer->Print(
+    variables_,
+    ";\n"
+    "private $type_name$ $name$_;\n");
+  AddDeprecatedFlag(printer);
+  printer->Print(
+    variables_,
+    "$access_level$ $type_name$ $property_name$ {\n"
+    "  get { return $name$_; }\n"
+    "  set {\n"
+    "    pb::Freezable.CheckMutable(this);\n"
+    "    $name$_ = value;\n"
+    "  }\n"
+    "}\n");
+}
+
+void WrapperFieldGenerator::GenerateMergingCode(io::Printer* printer) {
+  printer->Print(
+    variables_,
+    "if (other.$has_property_check$) {\n"
+    "  if ($has_not_property_check$ || other.$property_name$ != $default_value$) {\n"
+    "    $property_name$ = other.$property_name$;\n"
+    "  }\n"
+    "}\n");
+}
+
+void WrapperFieldGenerator::GenerateParsingCode(io::Printer* printer) {
+  printer->Print(
+    variables_,
+    "$type_name$ value = _single_$name$_codec.Read(input);\n"
+    "if ($has_not_property_check$ || value != $default_value$) {\n"
+    "  $property_name$ = value;\n"
+    "}\n");
+}
+
+void WrapperFieldGenerator::GenerateSerializationCode(io::Printer* printer) {
+  printer->Print(
+    variables_,
+    "if ($has_property_check$) {\n"
+    "  _single_$name$_codec.WriteTagAndValue(output, $property_name$);\n"
+    "}\n");
+}
+
+void WrapperFieldGenerator::GenerateSerializedSizeCode(io::Printer* printer) {
+  printer->Print(
+    variables_,
+    "if ($has_property_check$) {\n"
+    "  size += _single_$name$_codec.CalculateSizeWithTag($property_name$);\n"
+    "}\n");
+}
+
+void WrapperFieldGenerator::WriteHash(io::Printer* printer) {
+  printer->Print(
+    variables_,
+    "if ($has_property_check$) hash ^= $property_name$.GetHashCode();\n");
+}
+
+void WrapperFieldGenerator::WriteEquals(io::Printer* printer) {
+  printer->Print(
+    variables_,
+    "if ($property_name$ != other.$property_name$) return false;\n");
+}
+
+void WrapperFieldGenerator::WriteToString(io::Printer* printer) {
+  // TODO: Implement if we ever actually need it...
+}
+
+void WrapperFieldGenerator::GenerateCloningCode(io::Printer* printer) {
+  printer->Print(variables_,
+    "$property_name$ = other.$property_name$;\n");
+}
+
+void WrapperFieldGenerator::GenerateCodecCode(io::Printer* printer) {
+  if (is_value_type) {
+    printer->Print(
+      variables_,
+      "pb::FieldCodec.ForStructWrapper<$nonnullable_type_name$>($tag$)");
+  } else {
+    printer->Print(
+      variables_,
+      "pb::FieldCodec.ForClassWrapper<$type_name$>($tag$)");
+  }
+}
+
+WrapperOneofFieldGenerator::WrapperOneofFieldGenerator(const FieldDescriptor* descriptor,
+    int fieldOrdinal)
+    : WrapperFieldGenerator(descriptor, fieldOrdinal) {
+    SetCommonOneofFieldVariables(&variables_);
+}
+
+WrapperOneofFieldGenerator::~WrapperOneofFieldGenerator() {
+}
+
+void WrapperOneofFieldGenerator::GenerateMembers(io::Printer* printer) {
+  // Note: deliberately _oneof_$name$_codec, not _$oneof_name$_codec... we have one codec per field.
+  printer->Print(
+        variables_,
+        "private static readonly pb::FieldCodec<$type_name$> _oneof_$name$_codec = ");
+  GenerateCodecCode(printer);
+  printer->Print(";\n");
+  AddDeprecatedFlag(printer);
+  printer->Print(
+    variables_,
+    "$access_level$ $type_name$ $property_name$ {\n"
+    "  get { return $has_property_check$ ? ($type_name$) $oneof_name$_ : ($type_name$) null; }\n"
+    "  set {\n"
+    "    pb::Freezable.CheckMutable(this);\n"
+    "    $oneof_name$_ = value;\n"
+    "    $oneof_name$Case_ = value == null ? $oneof_property_name$OneofCase.None : $oneof_property_name$OneofCase.$property_name$;\n"
+    "  }\n"
+    "}\n");
+}
+
+void WrapperOneofFieldGenerator::GenerateParsingCode(io::Printer* printer) {
+  printer->Print(
+    variables_,
+    "$property_name$ = _oneof_$name$_codec.Read(input);\n");
+}
+
+void WrapperOneofFieldGenerator::GenerateSerializationCode(io::Printer* printer) {
+  // TODO: I suspect this is wrong...
+  printer->Print(
+    variables_,
+    "if ($has_property_check$) {\n"
+    "  _oneof_$name$_codec.WriteTagAndValue(output, ($type_name$) $oneof_name$_);\n"
+    "}\n");
+}
+
+void WrapperOneofFieldGenerator::GenerateSerializedSizeCode(io::Printer* printer) {
+  // TODO: I suspect this is wrong...
+  printer->Print(
+    variables_,
+    "if ($has_property_check$) {\n"
+    "  size += _oneof_$name$_codec.CalculateSizeWithTag($property_name$);\n"
+    "}\n");
+}
+
+}  // namespace csharp
+}  // namespace compiler
+}  // namespace protobuf
+}  // namespace google
diff --git a/src/google/protobuf/compiler/csharp/csharp_wrapper_field.h b/src/google/protobuf/compiler/csharp/csharp_wrapper_field.h
new file mode 100644
index 00000000..6e2414af
--- /dev/null
+++ b/src/google/protobuf/compiler/csharp/csharp_wrapper_field.h
@@ -0,0 +1,85 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef GOOGLE_PROTOBUF_COMPILER_CSHARP_WRAPPER_FIELD_H__
+#define GOOGLE_PROTOBUF_COMPILER_CSHARP_WRAPPER_FIELD_H__
+
+#include <string>
+
+#include <google/protobuf/compiler/code_generator.h>
+#include <google/protobuf/compiler/csharp/csharp_field_base.h>
+
+namespace google {
+namespace protobuf {
+namespace compiler {
+namespace csharp {
+
+class WrapperFieldGenerator : public FieldGeneratorBase {
+ public:
+  WrapperFieldGenerator(const FieldDescriptor* descriptor, int fieldOrdinal);
+  ~WrapperFieldGenerator();
+
+  virtual void GenerateCodecCode(io::Printer* printer);
+  virtual void GenerateCloningCode(io::Printer* printer);
+  virtual void GenerateMembers(io::Printer* printer);
+  virtual void GenerateMergingCode(io::Printer* printer);
+  virtual void GenerateParsingCode(io::Printer* printer);
+  virtual void GenerateSerializationCode(io::Printer* printer);
+  virtual void GenerateSerializedSizeCode(io::Printer* printer);
+
+  virtual void WriteHash(io::Printer* printer);
+  virtual void WriteEquals(io::Printer* printer);
+  virtual void WriteToString(io::Printer* printer);
+
+ private:
+  bool is_value_type; // True for int32 etc; false for bytes and string
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(WrapperFieldGenerator);
+};
+
+class WrapperOneofFieldGenerator : public WrapperFieldGenerator {
+ public:
+  WrapperOneofFieldGenerator(const FieldDescriptor* descriptor, int fieldOrdinal);
+  ~WrapperOneofFieldGenerator();
+
+  virtual void GenerateMembers(io::Printer* printer);
+  virtual void GenerateParsingCode(io::Printer* printer);
+  virtual void GenerateSerializationCode(io::Printer* printer);
+  virtual void GenerateSerializedSizeCode(io::Printer* printer);
+
+ private:
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(WrapperOneofFieldGenerator);
+};
+
+}  // namespace csharp
+}  // namespace compiler
+}  // namespace protobuf
+}  // namespace google
+
+#endif  // GOOGLE_PROTOBUF_COMPILER_CSHARP_WRAPPER_FIELD_H__
diff --git a/src/google/protobuf/unittest_well_known_types.proto b/src/google/protobuf/unittest_well_known_types.proto
index e157260e..2cb7775c 100644
--- a/src/google/protobuf/unittest_well_known_types.proto
+++ b/src/google/protobuf/unittest_well_known_types.proto
@@ -2,6 +2,7 @@ syntax = "proto3";
 
 package protobuf_unittest;
 
+option csharp_namespace = "Google.Protobuf.TestProtos";
 option java_multiple_files = true;
 option java_package = "com.google.protobuf.test";
 
@@ -17,6 +18,8 @@ import "google/protobuf/type.proto";
 import "google/protobuf/wrappers.proto";
 
 // Test that we can include all well-known types.
+// Each wrapper type is included separately, as languages
+// map handle different wrappers in different ways.
 message TestWellKnownTypes {
   google.protobuf.Any any_field = 1;
   google.protobuf.Api api_field = 2;
@@ -27,5 +30,83 @@ message TestWellKnownTypes {
   google.protobuf.Struct struct_field = 7;
   google.protobuf.Timestamp timestamp_field = 8;
   google.protobuf.Type type_field = 9;
-  google.protobuf.Int32Value int32_field = 10;
+  google.protobuf.DoubleValue double_field = 10;
+  google.protobuf.FloatValue float_field = 11;
+  google.protobuf.Int64Value int64_field = 12;
+  google.protobuf.UInt64Value uint64_field = 13;
+  google.protobuf.Int32Value int32_field = 14;
+  google.protobuf.UInt32Value uint32_field = 15;
+  google.protobuf.BoolValue bool_field = 16;
+  google.protobuf.StringValue string_field = 17;
+  google.protobuf.BytesValue bytes_field = 18;
+}
+
+// A repeated field for each well-known type.
+message RepeatedWellKnownTypes {
+  repeated google.protobuf.Any any_field = 1;
+  repeated google.protobuf.Api api_field = 2;
+  repeated google.protobuf.Duration duration_field = 3;
+  repeated google.protobuf.Empty empty_field = 4;
+  repeated google.protobuf.FieldMask field_mask_field = 5;
+  repeated google.protobuf.SourceContext source_context_field = 6;
+  repeated google.protobuf.Struct struct_field = 7;
+  repeated google.protobuf.Timestamp timestamp_field = 8;
+  repeated google.protobuf.Type type_field = 9;
+  // These don't actually make a lot of sense, but they're not prohibited...
+  repeated google.protobuf.DoubleValue double_field = 10;
+  repeated google.protobuf.FloatValue float_field = 11;
+  repeated google.protobuf.Int64Value int64_field = 12;
+  repeated google.protobuf.UInt64Value uint64_field = 13;
+  repeated google.protobuf.Int32Value int32_field = 14;
+  repeated google.protobuf.UInt32Value uint32_field = 15;
+  repeated google.protobuf.BoolValue bool_field = 16;
+  repeated google.protobuf.StringValue string_field = 17;
+  repeated google.protobuf.BytesValue bytes_field = 18;
+}
+
+message OneofWellKnownTypes {
+  oneof oneof_field {
+    google.protobuf.Any any_field = 1;
+    google.protobuf.Api api_field = 2;
+    google.protobuf.Duration duration_field = 3;
+    google.protobuf.Empty empty_field = 4;
+    google.protobuf.FieldMask field_mask_field = 5;
+    google.protobuf.SourceContext source_context_field = 6;
+    google.protobuf.Struct struct_field = 7;
+    google.protobuf.Timestamp timestamp_field = 8;
+    google.protobuf.Type type_field = 9;
+    google.protobuf.DoubleValue double_field = 10;
+    google.protobuf.FloatValue float_field = 11;
+    google.protobuf.Int64Value int64_field = 12;
+    google.protobuf.UInt64Value uint64_field = 13;
+    google.protobuf.Int32Value int32_field = 14;
+    google.protobuf.UInt32Value uint32_field = 15;
+    google.protobuf.BoolValue bool_field = 16;
+    google.protobuf.StringValue string_field = 17;
+    google.protobuf.BytesValue bytes_field = 18;
+  }
+}
+
+// A map field for each well-known type. We only
+// need to worry about the value part of the map being the
+// well-known types, as messages can't be map keys.
+message MapWellKnownTypes {
+  map<int32,google.protobuf.Any> any_field = 1;
+  map<int32,google.protobuf.Api> api_field = 2;
+  map<int32,google.protobuf.Duration> duration_field = 3;
+  map<int32,google.protobuf.Empty> empty_field = 4;
+  map<int32,google.protobuf.FieldMask> field_mask_field = 5;
+  map<int32,google.protobuf.SourceContext> source_context_field = 6;
+  map<int32,google.protobuf.Struct> struct_field = 7;
+  map<int32,google.protobuf.Timestamp> timestamp_field = 8;
+  map<int32,google.protobuf.Type> type_field = 9;
+  map<int32,google.protobuf.DoubleValue> double_field = 10;
+  map<int32,google.protobuf.FloatValue> float_field = 11;
+  map<int32,google.protobuf.Int64Value> int64_field = 12;
+  map<int32,google.protobuf.UInt64Value> uint64_field = 13;
+  map<int32,google.protobuf.Int32Value> int32_field = 14;
+  map<int32,google.protobuf.UInt32Value> uint32_field = 15;
+  map<int32,google.protobuf.BoolValue> bool_field = 16;
+  map<int32,google.protobuf.StringValue> string_field = 17;
+  map<int32,google.protobuf.BytesValue> bytes_field = 18;
 }