More tests, more fixes.

8 files changed, 860 insertions, 26 deletions

diff --git a/csharp/ProtocolBuffers.Test/CodedInputStreamTest.cs b/csharp/ProtocolBuffers.Test/CodedInputStreamTest.cs
index 9dc34ca7..46d0f05b 100644
--- a/csharp/ProtocolBuffers.Test/CodedInputStreamTest.cs
+++ b/csharp/ProtocolBuffers.Test/CodedInputStreamTest.cs
@@ -17,6 +17,7 @@ using System;
 using System.IO;
 using Google.ProtocolBuffers.TestProtos;
 using NUnit.Framework;
+using System.Diagnostics;
 
 namespace Google.ProtocolBuffers {
   [TestFixture]
@@ -190,7 +191,6 @@ namespace Google.ProtocolBuffers {
 
       byte[] rawBytes = message.ToByteArray();
       Assert.AreEqual(rawBytes.Length, message.SerializedSize);
-
       TestAllTypes message2 = TestAllTypes.ParseFrom(rawBytes);
       TestUtil.AssertAllFieldsSet(message2);
 
diff --git a/csharp/ProtocolBuffers.Test/DynamicMessageTest.cs b/csharp/ProtocolBuffers.Test/DynamicMessageTest.cs
index 4a666935..dcf6e0fb 100644
--- a/csharp/ProtocolBuffers.Test/DynamicMessageTest.cs
+++ b/csharp/ProtocolBuffers.Test/DynamicMessageTest.cs
@@ -9,13 +9,12 @@ namespace Google.ProtocolBuffers {
   public class DynamicMessageTest {
 
     private ReflectionTester reflectionTester;
-
     private ReflectionTester extensionsReflectionTester;
 
     [SetUp]
     public void SetUp() {
-      reflectionTester = new ReflectionTester(TestAllTypes.Descriptor, null);
-      extensionsReflectionTester = new ReflectionTester(TestAllExtensions.Descriptor, TestUtil.CreateExtensionRegistry());
+      reflectionTester = ReflectionTester.CreateTestAllTypesInstance();
+      extensionsReflectionTester = ReflectionTester.CreateTestAllExtensionsInstance();
     }
 
     [Test]
diff --git a/csharp/ProtocolBuffers.Test/GeneratedMessageTest.cs b/csharp/ProtocolBuffers.Test/GeneratedMessageTest.cs
new file mode 100644
index 00000000..36a63c17
--- /dev/null
+++ b/csharp/ProtocolBuffers.Test/GeneratedMessageTest.cs
@@ -0,0 +1,224 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using NUnit.Framework;
+using Google.ProtocolBuffers.TestProtos;
+
+namespace Google.ProtocolBuffers {
+  [TestFixture]
+  public class GeneratedMessageTest {
+    ReflectionTester reflectionTester;
+    ReflectionTester extensionsReflectionTester;
+    
+    [SetUp]
+    public void SetUp() {
+      reflectionTester = ReflectionTester.CreateTestAllTypesInstance();
+      extensionsReflectionTester = ReflectionTester.CreateTestAllExtensionsInstance();
+    }
+    
+    [Test]
+    public void DefaultInstance() {
+      Assert.AreSame(TestAllTypes.DefaultInstance, TestAllTypes.DefaultInstance.DefaultInstanceForType);
+      Assert.AreSame(TestAllTypes.DefaultInstance, TestAllTypes.CreateBuilder().DefaultInstanceForType);
+    }
+
+    [Test]
+    public void Accessors() {
+      TestAllTypes.Builder builder = TestAllTypes.CreateBuilder();
+      TestUtil.SetAllFields(builder);
+      TestAllTypes message = builder.Build();
+      TestUtil.AssertAllFieldsSet(message);
+    }
+    
+    [Test]
+    public void RepeatedSetters() {
+      TestAllTypes.Builder builder = TestAllTypes.CreateBuilder();
+      TestUtil.SetAllFields(builder);
+      TestUtil.ModifyRepeatedFields(builder);
+      TestAllTypes message = builder.Build();
+      TestUtil.AssertRepeatedFieldsModified(message);
+    }
+
+    [Test]
+    public void RepeatedAppend() {
+      TestAllTypes.Builder builder = TestAllTypes.CreateBuilder();
+
+      builder.AddRangeRepeatedInt32(new int[]{1, 2, 3, 4});
+      builder.AddRangeRepeatedForeignEnum((new ForeignEnum[] { ForeignEnum.FOREIGN_BAZ }));
+
+      ForeignMessage foreignMessage = ForeignMessage.CreateBuilder().SetC(12).Build();
+      builder.AddRangeRepeatedForeignMessage(new ForeignMessage[] {foreignMessage});
+
+      TestAllTypes message = builder.Build();
+      TestUtil.AssertEqual(message.RepeatedInt32List, new int[]{1, 2, 3, 4});
+      TestUtil.AssertEqual(message.RepeatedForeignEnumList, new ForeignEnum[] {ForeignEnum.FOREIGN_BAZ});
+      Assert.AreEqual(1, message.RepeatedForeignMessageCount);
+      Assert.AreEqual(12, message.GetRepeatedForeignMessage(0).C);
+    }
+
+    [Test]
+    public void SettingForeignMessageUsingBuilder() {
+      TestAllTypes message = TestAllTypes.CreateBuilder()
+          // Pass builder for foreign message instance.
+          .SetOptionalForeignMessage(ForeignMessage.CreateBuilder().SetC(123))
+          .Build();
+      TestAllTypes expectedMessage = TestAllTypes.CreateBuilder()
+          // Create expected version passing foreign message instance explicitly.
+          .SetOptionalForeignMessage(ForeignMessage.CreateBuilder().SetC(123).Build())
+          .Build();
+      Assert.AreEqual(expectedMessage, message);
+    }
+
+    [Test]
+    public void SettingRepeatedForeignMessageUsingBuilder() {
+      TestAllTypes message = TestAllTypes.CreateBuilder()
+          // Pass builder for foreign message instance.
+          .AddRepeatedForeignMessage(ForeignMessage.CreateBuilder().SetC(456))
+          .Build();
+      TestAllTypes expectedMessage = TestAllTypes.CreateBuilder()
+          // Create expected version passing foreign message instance explicitly.
+          .AddRepeatedForeignMessage(ForeignMessage.CreateBuilder().SetC(456).Build())
+          .Build();
+      Assert.AreEqual(expectedMessage, message);
+    }
+
+    
+    [Test]
+    public void Defaults() {
+      TestUtil.AssertClear(TestAllTypes.DefaultInstance);
+      TestUtil.AssertClear(TestAllTypes.CreateBuilder().Build());
+
+      Assert.AreEqual("\u1234", TestExtremeDefaultValues.DefaultInstance.Utf8String);
+    }
+
+    [Test]
+    public void ReflectionGetters() {
+      TestAllTypes.Builder builder = TestAllTypes.CreateBuilder();
+      TestUtil.SetAllFields(builder);
+      TestAllTypes message = builder.Build();
+      reflectionTester.AssertAllFieldsSetViaReflection(message);
+    }
+
+    [Test]
+    public void ReflectionSetters() {
+      TestAllTypes.Builder builder = TestAllTypes.CreateBuilder();
+      reflectionTester.SetAllFieldsViaReflection(builder);
+      TestAllTypes message = builder.Build();
+      TestUtil.AssertAllFieldsSet(message);
+    }
+
+    [Test]
+    public void ReflectionRepeatedSetters() {
+      TestAllTypes.Builder builder = TestAllTypes.CreateBuilder();
+      reflectionTester.SetAllFieldsViaReflection(builder);
+      reflectionTester.ModifyRepeatedFieldsViaReflection(builder);
+      TestAllTypes message = builder.Build();
+      TestUtil.AssertRepeatedFieldsModified(message);
+    }
+
+    [Test]
+    public void ReflectionDefaults() {
+      reflectionTester.AssertClearViaReflection(TestAllTypes.DefaultInstance);
+      reflectionTester.AssertClearViaReflection(TestAllTypes.CreateBuilder().Build());
+    }
+    // =================================================================
+    // Extensions.
+
+    [Test]
+    public void ExtensionAccessors() {
+      TestAllExtensions.Builder builder = TestAllExtensions.CreateBuilder();
+      TestUtil.SetAllExtensions(builder);
+      TestAllExtensions message = builder.Build();
+      TestUtil.AssertAllExtensionsSet(message);
+    }
+
+    [Test]
+    public void ExtensionRepeatedSetters() {
+      TestAllExtensions.Builder builder = TestAllExtensions.CreateBuilder();
+      TestUtil.SetAllExtensions(builder);
+      TestUtil.ModifyRepeatedExtensions(builder);
+      TestAllExtensions message = builder.Build();
+      TestUtil.AssertRepeatedExtensionsModified(message);
+    }
+
+    [Test]
+    public void ExtensionDefaults() {
+      TestUtil.AssertExtensionsClear(TestAllExtensions.DefaultInstance);
+      TestUtil.AssertExtensionsClear(TestAllExtensions.CreateBuilder().Build());
+    }
+
+    [Test]
+    public void ExtensionReflectionGetters() {
+      TestAllExtensions.Builder builder = TestAllExtensions.CreateBuilder();
+      TestUtil.SetAllExtensions(builder);
+      TestAllExtensions message = builder.Build();
+      extensionsReflectionTester.AssertAllFieldsSetViaReflection(message);
+    }
+
+    [Test]
+    public void ExtensionReflectionSetters() {
+      TestAllExtensions.Builder builder = TestAllExtensions.CreateBuilder();
+      extensionsReflectionTester.SetAllFieldsViaReflection(builder);
+      TestAllExtensions message = builder.Build();
+      TestUtil.AssertAllExtensionsSet(message);
+    }
+
+    [Test]
+    public void ExtensionReflectionRepeatedSetters() {
+      TestAllExtensions.Builder builder = TestAllExtensions.CreateBuilder();
+      extensionsReflectionTester.SetAllFieldsViaReflection(builder);
+      extensionsReflectionTester.ModifyRepeatedFieldsViaReflection(builder);
+      TestAllExtensions message = builder.Build();
+      TestUtil.AssertRepeatedExtensionsModified(message);
+    }
+
+    [Test]
+    public void ExtensionReflectionDefaults() {
+      extensionsReflectionTester.AssertClearViaReflection(TestAllExtensions.DefaultInstance);
+      extensionsReflectionTester.AssertClearViaReflection(TestAllExtensions.CreateBuilder().Build());
+    }
+
+    public void testClearExtension() {
+      // clearExtension() is not actually used in TestUtil, so try it manually.
+      Assert.IsFalse(TestAllExtensions.CreateBuilder()
+          .SetExtension(UnitTestProtoFile.OptionalInt32Extension, 1)
+          .ClearExtension(UnitTestProtoFile.OptionalInt32Extension)
+          .HasExtension(UnitTestProtoFile.OptionalInt32Extension));
+      Assert.AreEqual(0,
+        TestAllExtensions.CreateBuilder()
+          .AddExtension(UnitTestProtoFile.RepeatedInt32Extension, 1)
+          .ClearExtension(UnitTestProtoFile.RepeatedInt32Extension)
+          .GetExtensionCount(UnitTestProtoFile.RepeatedInt32Extension));
+    }
+
+    // =================================================================
+    // multiple_files_test
+    /* FIXME: Find this proto!
+    public void MultipleFilesOption() {
+      // We mostly just want to check that things compile.
+      MessageWithNoOuter message = MessageWithNoOuter.CreateBuilder()
+          .setNested(MessageWithNoOuter.NestedMessage.CreateBuilder().setI(1))
+          .addForeign(TestAllTypes.CreateBuilder().setOptionalInt32(1))
+          .setNestedEnum(MessageWithNoOuter.NestedEnum.BAZ)
+          .setForeignEnum(EnumWithNoOuter.BAR)
+          .Build();
+      Assert.AreEqual(message, MessageWithNoOuter.parseFrom(message.toByteString()));
+
+      Assert.AreEqual(MultipleFilesTestProto.getDescriptor(),
+                   MessageWithNoOuter.getDescriptor().getFile());
+
+      Descriptors.FieldDescriptor field =
+        MessageWithNoOuter.getDescriptor().findFieldByName("foreign_enum");
+      Assert.AreEqual(EnumWithNoOuter.BAR.getValueDescriptor(),
+                   message.getField(field));
+
+      Assert.AreEqual(MultipleFilesTestProto.getDescriptor(),
+                   ServiceWithNoOuter.getDescriptor().getFile());
+
+      assertFalse(
+        TestAllExtensions.getDefaultInstance().hasExtension(
+          MultipleFilesTestProto.extensionWithOuter));
+    }
+    */
+  }
+}
diff --git a/csharp/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj b/csharp/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
index 54e07be1..314dad34 100644
--- a/csharp/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
+++ b/csharp/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj
@@ -50,6 +50,7 @@
     <Compile Include="CodedOutputStreamTest.cs" />
     <Compile Include="DescriptorsTest.cs" />
     <Compile Include="DynamicMessageTest.cs" />
+    <Compile Include="GeneratedMessageTest.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ReflectionTester.cs" />
     <Compile Include="TestProtos\UnitTestEmbedOptimizeForProtoFile.cs" />
diff --git a/csharp/ProtocolBuffers.Test/ReflectionTester.cs b/csharp/ProtocolBuffers.Test/ReflectionTester.cs
index a0d3cec7..3c57c653 100644
--- a/csharp/ProtocolBuffers.Test/ReflectionTester.cs
+++ b/csharp/ProtocolBuffers.Test/ReflectionTester.cs
@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Text;
 using Google.ProtocolBuffers.Descriptors;
 using NUnit.Framework;
+using Google.ProtocolBuffers.TestProtos;
 
 namespace Google.ProtocolBuffers {
   /// <summary>
@@ -52,7 +53,7 @@ namespace Google.ProtocolBuffers {
     /// All of the TestAllExtensions extensions must be registered in the registry.
     /// TODO(jonskeet): Enforce all of these with two factory methods.
     /// </summary>
-    public ReflectionTester(MessageDescriptor baseDescriptor,
+    private ReflectionTester(MessageDescriptor baseDescriptor,
                             ExtensionRegistry extensionRegistry) {
       this.baseDescriptor = baseDescriptor;
       this.extensionRegistry = extensionRegistry;
@@ -129,9 +130,24 @@ namespace Google.ProtocolBuffers {
       Assert.IsNotNull(importBaz     );
     }
 
-    /**
-     * Shorthand to get a FieldDescriptor for a field of unittest::TestAllTypes.
-     */
+    /// <summary>
+    /// Creates an instance for the TestAllTypes message, with no extension registry.
+    /// </summary>
+    public static ReflectionTester CreateTestAllTypesInstance() {
+      return new ReflectionTester(TestAllTypes.Descriptor, null);
+    }
+
+    /// <summary>
+    /// Creates an instance for the TestAllExtensions message, with an
+    /// extension registry from TestUtil.CreateExtensionRegistry.
+    /// </summary>
+    public static ReflectionTester CreateTestAllExtensionsInstance() {      
+      return new ReflectionTester(TestAllExtensions.Descriptor, TestUtil.CreateExtensionRegistry());
+    }
+
+    /// <summary>
+    /// Shorthand to get a FieldDescriptor for a field of unittest::TestAllTypes.
+    /// </summary>
     private FieldDescriptor f(String name) {
       FieldDescriptor result;
       if (extensionRegistry == null) {
@@ -143,11 +159,10 @@ namespace Google.ProtocolBuffers {
       return result;
     }
 
-    /**
-     * Calls {@code parent.CreateBuilderForField()} or uses the
-     * {@code ExtensionRegistry} to find an appropriateIBuilder, depending
-     * on what type is being tested.
-     */
+    /// <summary>
+    /// Calls parent.CreateBuilderForField() or uses the extension registry
+    /// to find an appropriate builder, depending on what type is being tested.
+    /// </summary>
     private IBuilder CreateBuilderForField(IBuilder parent, FieldDescriptor field) {
       if (extensionRegistry == null) {
         return parent.CreateBuilderForField(field);
@@ -159,13 +174,11 @@ namespace Google.ProtocolBuffers {
       }
     }
 
-    // -------------------------------------------------------------------
-
-    /**
-     * Set every field of {@code message} to the values expected by
-     * {@code assertAllFieldsSet()}, using the {@link MessageIBuilder}
-     * reflection interface.
-     */
+    /// <summary>
+    /// Sets every field of the message to the values expected by
+    /// AssertAllFieldsSet, using the reflection interface.
+    /// </summary>
+    /// <param name="message"></param>
     internal void SetAllFieldsViaReflection(IBuilder message) {
       message[f("optional_int32"   )] = 101 ;
       message[f("optional_int64"   )] = 102L;
diff --git a/csharp/ProtocolBuffers.Test/TestProtos/UnitTestProtoFile.cs b/csharp/ProtocolBuffers.Test/TestProtos/UnitTestProtoFile.cs
index e5099ce8..29b6a6b4 100644
--- a/csharp/ProtocolBuffers.Test/TestProtos/UnitTestProtoFile.cs
+++ b/csharp/ProtocolBuffers.Test/TestProtos/UnitTestProtoFile.cs
@@ -4841,7 +4841,7 @@ namespace Google.ProtocolBuffers.TestProtos {
         result.repeatedNestedEnum_.Add(value);
         return this;
       }
-      public Builder AddAllRepeatedNestedEnum(scg::IEnumerable<self::TestAllTypes.Types.NestedEnum> values) {
+      public Builder AddRangeRepeatedNestedEnum(scg::IEnumerable<self::TestAllTypes.Types.NestedEnum> values) {
         if (result.repeatedNestedEnum_.Count == 0) {
           result.repeatedNestedEnum_ = new scg::List<self::TestAllTypes.Types.NestedEnum>();
         }
@@ -4874,7 +4874,7 @@ namespace Google.ProtocolBuffers.TestProtos {
         result.repeatedForeignEnum_.Add(value);
         return this;
       }
-      public Builder AddAllRepeatedForeignEnum(scg::IEnumerable<self::ForeignEnum> values) {
+      public Builder AddRangeRepeatedForeignEnum(scg::IEnumerable<self::ForeignEnum> values) {
         if (result.repeatedForeignEnum_.Count == 0) {
           result.repeatedForeignEnum_ = new scg::List<self::ForeignEnum>();
         }
@@ -4907,7 +4907,7 @@ namespace Google.ProtocolBuffers.TestProtos {
         result.repeatedImportEnum_.Add(value);
         return this;
       }
-      public Builder AddAllRepeatedImportEnum(scg::IEnumerable<self::ImportEnum> values) {
+      public Builder AddRangeRepeatedImportEnum(scg::IEnumerable<self::ImportEnum> values) {
         if (result.repeatedImportEnum_.Count == 0) {
           result.repeatedImportEnum_ = new scg::List<self::ImportEnum>();
         }
@@ -11640,7 +11640,7 @@ namespace Google.ProtocolBuffers.TestProtos {
         result.repeatedEnumField_.Add(value);
         return this;
       }
-      public Builder AddAllRepeatedEnumField(scg::IEnumerable<self::ForeignEnum> values) {
+      public Builder AddRangeRepeatedEnumField(scg::IEnumerable<self::ForeignEnum> values) {
         if (result.repeatedEnumField_.Count == 0) {
           result.repeatedEnumField_ = new scg::List<self::ForeignEnum>();
         }
diff --git a/csharp/ProtocolBuffers.Test/TestUtil.cs b/csharp/ProtocolBuffers.Test/TestUtil.cs
index 2cc1b5a2..6e3b9f18 100644
--- a/csharp/ProtocolBuffers.Test/TestUtil.cs
+++ b/csharp/ProtocolBuffers.Test/TestUtil.cs
@@ -736,5 +736,603 @@ namespace Google.ProtocolBuffers {
       message.SetExtension(UnitTestProtoFile.DefaultStringPieceExtension, "424");
       message.SetExtension(UnitTestProtoFile.DefaultCordExtension, "425");
     }
+
+    public static void ModifyRepeatedFields(TestAllTypes.Builder message) {
+      message.SetRepeatedInt32(1, 501);
+      message.SetRepeatedInt64(1, 502);
+      message.SetRepeatedUint32(1, 503);
+      message.SetRepeatedUint64(1, 504);
+      message.SetRepeatedSint32(1, 505);
+      message.SetRepeatedSint64(1, 506);
+      message.SetRepeatedFixed32(1, 507);
+      message.SetRepeatedFixed64(1, 508);
+      message.SetRepeatedSfixed32(1, 509);
+      message.SetRepeatedSfixed64(1, 510);
+      message.SetRepeatedFloat(1, 511);
+      message.SetRepeatedDouble(1, 512);
+      message.SetRepeatedBool(1, true);
+      message.SetRepeatedString(1, "515");
+      message.SetRepeatedBytes(1, ToBytes("516"));
+
+      message.SetRepeatedGroup(1, TestAllTypes.Types.RepeatedGroup.CreateBuilder().SetA(517).Build());
+      message.SetRepeatedNestedMessage(1, TestAllTypes.Types.NestedMessage.CreateBuilder().SetBb(518).Build());
+      message.SetRepeatedForeignMessage(1, ForeignMessage.CreateBuilder().SetC(519).Build());
+      message.SetRepeatedImportMessage(1, ImportMessage.CreateBuilder().SetD(520).Build());
+
+      message.SetRepeatedNestedEnum(1, TestAllTypes.Types.NestedEnum.FOO);
+      message.SetRepeatedForeignEnum(1, ForeignEnum.FOREIGN_FOO);
+      message.SetRepeatedImportEnum(1, ImportEnum.IMPORT_FOO);
+
+      message.SetRepeatedStringPiece(1, "524");
+      message.SetRepeatedCord(1, "525");
+    }
+
+    public static void AssertRepeatedFieldsModified(TestAllTypes message) {
+      // ModifyRepeatedFields only sets the second repeated element of each
+      // field.  In addition to verifying this, we also verify that the first
+      // element and size were *not* modified.
+      Assert.AreEqual(2, message.RepeatedInt32Count);
+      Assert.AreEqual(2, message.RepeatedInt64Count);
+      Assert.AreEqual(2, message.RepeatedUint32Count);
+      Assert.AreEqual(2, message.RepeatedUint64Count);
+      Assert.AreEqual(2, message.RepeatedSint32Count);
+      Assert.AreEqual(2, message.RepeatedSint64Count);
+      Assert.AreEqual(2, message.RepeatedFixed32Count);
+      Assert.AreEqual(2, message.RepeatedFixed64Count);
+      Assert.AreEqual(2, message.RepeatedSfixed32Count);
+      Assert.AreEqual(2, message.RepeatedSfixed64Count);
+      Assert.AreEqual(2, message.RepeatedFloatCount);
+      Assert.AreEqual(2, message.RepeatedDoubleCount);
+      Assert.AreEqual(2, message.RepeatedBoolCount);
+      Assert.AreEqual(2, message.RepeatedStringCount);
+      Assert.AreEqual(2, message.RepeatedBytesCount);
+
+      Assert.AreEqual(2, message.RepeatedGroupCount);
+      Assert.AreEqual(2, message.RepeatedNestedMessageCount);
+      Assert.AreEqual(2, message.RepeatedForeignMessageCount);
+      Assert.AreEqual(2, message.RepeatedImportMessageCount);
+      Assert.AreEqual(2, message.RepeatedNestedEnumCount);
+      Assert.AreEqual(2, message.RepeatedForeignEnumCount);
+      Assert.AreEqual(2, message.RepeatedImportEnumCount);
+
+      Assert.AreEqual(2, message.RepeatedStringPieceCount);
+      Assert.AreEqual(2, message.RepeatedCordCount);
+
+      Assert.AreEqual(201, message.GetRepeatedInt32(0));
+      Assert.AreEqual(202L, message.GetRepeatedInt64(0));
+      Assert.AreEqual(203U, message.GetRepeatedUint32(0));
+      Assert.AreEqual(204UL, message.GetRepeatedUint64(0));
+      Assert.AreEqual(205, message.GetRepeatedSint32(0));
+      Assert.AreEqual(206L, message.GetRepeatedSint64(0));
+      Assert.AreEqual(207U, message.GetRepeatedFixed32(0));
+      Assert.AreEqual(208UL, message.GetRepeatedFixed64(0));
+      Assert.AreEqual(209, message.GetRepeatedSfixed32(0));
+      Assert.AreEqual(210L, message.GetRepeatedSfixed64(0));
+      Assert.AreEqual(211F, message.GetRepeatedFloat(0));
+      Assert.AreEqual(212D, message.GetRepeatedDouble(0));
+      Assert.AreEqual(true, message.GetRepeatedBool(0));
+      Assert.AreEqual("215", message.GetRepeatedString(0));
+      Assert.AreEqual(ToBytes("216"), message.GetRepeatedBytes(0));
+
+      Assert.AreEqual(217, message.GetRepeatedGroup(0).A);
+      Assert.AreEqual(218, message.GetRepeatedNestedMessage(0).Bb);
+      Assert.AreEqual(219, message.GetRepeatedForeignMessage(0).C);
+      Assert.AreEqual(220, message.GetRepeatedImportMessage(0).D);
+
+      Assert.AreEqual(TestAllTypes.Types.NestedEnum.BAR, message.GetRepeatedNestedEnum(0));
+      Assert.AreEqual(ForeignEnum.FOREIGN_BAR, message.GetRepeatedForeignEnum(0));
+      Assert.AreEqual(ImportEnum.IMPORT_BAR, message.GetRepeatedImportEnum(0));
+
+      Assert.AreEqual("224", message.GetRepeatedStringPiece(0));
+      Assert.AreEqual("225", message.GetRepeatedCord(0));
+
+      // Actually verify the second (modified) elements now.
+      Assert.AreEqual(501, message.GetRepeatedInt32(1));
+      Assert.AreEqual(502L, message.GetRepeatedInt64(1));
+      Assert.AreEqual(503U, message.GetRepeatedUint32(1));
+      Assert.AreEqual(504UL, message.GetRepeatedUint64(1));
+      Assert.AreEqual(505, message.GetRepeatedSint32(1));
+      Assert.AreEqual(506L, message.GetRepeatedSint64(1));
+      Assert.AreEqual(507U, message.GetRepeatedFixed32(1));
+      Assert.AreEqual(508UL, message.GetRepeatedFixed64(1));
+      Assert.AreEqual(509, message.GetRepeatedSfixed32(1));
+      Assert.AreEqual(510L, message.GetRepeatedSfixed64(1));
+      Assert.AreEqual(511F, message.GetRepeatedFloat(1));
+      Assert.AreEqual(512D, message.GetRepeatedDouble(1));
+      Assert.AreEqual(true, message.GetRepeatedBool(1));
+      Assert.AreEqual("515", message.GetRepeatedString(1));
+      Assert.AreEqual(ToBytes("516"), message.GetRepeatedBytes(1));
+
+      Assert.AreEqual(517, message.GetRepeatedGroup(1).A);
+      Assert.AreEqual(518, message.GetRepeatedNestedMessage(1).Bb);
+      Assert.AreEqual(519, message.GetRepeatedForeignMessage(1).C);
+      Assert.AreEqual(520, message.GetRepeatedImportMessage(1).D);
+
+      Assert.AreEqual(TestAllTypes.Types.NestedEnum.FOO, message.GetRepeatedNestedEnum(1));
+      Assert.AreEqual(ForeignEnum.FOREIGN_FOO, message.GetRepeatedForeignEnum(1));
+      Assert.AreEqual(ImportEnum.IMPORT_FOO, message.GetRepeatedImportEnum(1));
+
+      Assert.AreEqual("524", message.GetRepeatedStringPiece(1));
+      Assert.AreEqual("525", message.GetRepeatedCord(1));
+    }
+
+    /// <summary>
+    /// Helper to assert that sequences are equal.
+    /// </summary>
+    public static void AssertEqual<T>(IEnumerable<T> first, IEnumerable<T> second) {
+      using (IEnumerator<T> firstEnumerator = first.GetEnumerator()) {
+        foreach (T secondElement in second) {
+          Assert.IsTrue(firstEnumerator.MoveNext(), "First enumerator ran out of elements too early.");
+          Assert.AreEqual(firstEnumerator.Current, secondElement);
+        }
+        Assert.IsFalse(firstEnumerator.MoveNext(), "Second enumerator ran out of elements too early.");
+      }
+    }
+
+    public static void AssertAllExtensionsSet(TestAllExtensions message) {
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalInt32Extension   ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalInt64Extension   ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalUint32Extension  ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalUint64Extension  ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalSint32Extension  ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalSint64Extension  ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalFixed32Extension ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalFixed64Extension ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalSfixed32Extension));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalSfixed64Extension));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalFloatExtension   ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalDoubleExtension  ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalBoolExtension    ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalStringExtension  ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalBytesExtension   ));
+
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalGroupExtension         ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalNestedMessageExtension ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalForeignMessageExtension));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalImportMessageExtension ));
+
+    Assert.IsTrue(message.GetExtension(UnitTestProtoFile.OptionalGroupExtension         ).HasA);
+    Assert.IsTrue(message.GetExtension(UnitTestProtoFile.OptionalNestedMessageExtension ).HasBb);
+    Assert.IsTrue(message.GetExtension(UnitTestProtoFile.OptionalForeignMessageExtension).HasC);
+    Assert.IsTrue(message.GetExtension(UnitTestProtoFile.OptionalImportMessageExtension ).HasD);
+
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalNestedEnumExtension ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalForeignEnumExtension));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalImportEnumExtension ));
+
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalStringPieceExtension));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.OptionalCordExtension));
+
+    Assert.AreEqual(101  , message.GetExtension(UnitTestProtoFile.OptionalInt32Extension   ));
+    Assert.AreEqual(102L , message.GetExtension(UnitTestProtoFile.OptionalInt64Extension   ));
+    Assert.AreEqual(103U  , message.GetExtension(UnitTestProtoFile.OptionalUint32Extension  ));
+    Assert.AreEqual(104UL , message.GetExtension(UnitTestProtoFile.OptionalUint64Extension  ));
+    Assert.AreEqual(105  , message.GetExtension(UnitTestProtoFile.OptionalSint32Extension  ));
+    Assert.AreEqual(106L , message.GetExtension(UnitTestProtoFile.OptionalSint64Extension  ));
+    Assert.AreEqual(107U  , message.GetExtension(UnitTestProtoFile.OptionalFixed32Extension ));
+    Assert.AreEqual(108UL , message.GetExtension(UnitTestProtoFile.OptionalFixed64Extension ));
+    Assert.AreEqual(109  , message.GetExtension(UnitTestProtoFile.OptionalSfixed32Extension));
+    Assert.AreEqual(110L , message.GetExtension(UnitTestProtoFile.OptionalSfixed64Extension));
+    Assert.AreEqual(111F , message.GetExtension(UnitTestProtoFile.OptionalFloatExtension   ));
+    Assert.AreEqual(112D , message.GetExtension(UnitTestProtoFile.OptionalDoubleExtension  ));
+    Assert.AreEqual(true , message.GetExtension(UnitTestProtoFile.OptionalBoolExtension    ));
+    Assert.AreEqual("115", message.GetExtension(UnitTestProtoFile.OptionalStringExtension  ));
+    Assert.AreEqual(ToBytes("116"), message.GetExtension(UnitTestProtoFile.OptionalBytesExtension));
+
+    Assert.AreEqual(117, message.GetExtension(UnitTestProtoFile.OptionalGroupExtension         ).A);
+    Assert.AreEqual(118, message.GetExtension(UnitTestProtoFile.OptionalNestedMessageExtension ).Bb);
+    Assert.AreEqual(119, message.GetExtension(UnitTestProtoFile.OptionalForeignMessageExtension).C);
+    Assert.AreEqual(120, message.GetExtension(UnitTestProtoFile.OptionalImportMessageExtension ).D);
+
+    Assert.AreEqual(TestAllTypes.Types.NestedEnum.BAZ, message.GetExtension(UnitTestProtoFile.OptionalNestedEnumExtension));
+    Assert.AreEqual(ForeignEnum.FOREIGN_BAZ, message.GetExtension(UnitTestProtoFile.OptionalForeignEnumExtension));
+    Assert.AreEqual(ImportEnum.IMPORT_BAZ, message.GetExtension(UnitTestProtoFile.OptionalImportEnumExtension));
+
+    Assert.AreEqual("124", message.GetExtension(UnitTestProtoFile.OptionalStringPieceExtension));
+    Assert.AreEqual("125", message.GetExtension(UnitTestProtoFile.OptionalCordExtension));
+
+    // -----------------------------------------------------------------
+
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedInt32Extension   ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedInt64Extension   ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedUint32Extension  ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedUint64Extension  ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedSint32Extension  ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedSint64Extension  ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedFixed32Extension ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedFixed64Extension ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedSfixed32Extension));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedSfixed64Extension));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedFloatExtension   ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedDoubleExtension  ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedBoolExtension    ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedStringExtension  ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedBytesExtension   ));
+
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedGroupExtension         ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedNestedMessageExtension ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedForeignMessageExtension));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedImportMessageExtension ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedNestedEnumExtension    ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedForeignEnumExtension   ));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedImportEnumExtension    ));
+
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedStringPieceExtension));
+    Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedCordExtension));
+
+    Assert.AreEqual(201  , message.GetExtension(UnitTestProtoFile.RepeatedInt32Extension   , 0));
+    Assert.AreEqual(202L , message.GetExtension(UnitTestProtoFile.RepeatedInt64Extension   , 0));
+    Assert.AreEqual(203U  , message.GetExtension(UnitTestProtoFile.RepeatedUint32Extension  , 0));
+    Assert.AreEqual(204UL , message.GetExtension(UnitTestProtoFile.RepeatedUint64Extension  , 0));
+    Assert.AreEqual(205  , message.GetExtension(UnitTestProtoFile.RepeatedSint32Extension  , 0));
+    Assert.AreEqual(206L , message.GetExtension(UnitTestProtoFile.RepeatedSint64Extension  , 0));
+    Assert.AreEqual(207U  , message.GetExtension(UnitTestProtoFile.RepeatedFixed32Extension , 0));
+    Assert.AreEqual(208UL , message.GetExtension(UnitTestProtoFile.RepeatedFixed64Extension , 0));
+    Assert.AreEqual(209  , message.GetExtension(UnitTestProtoFile.RepeatedSfixed32Extension, 0));
+    Assert.AreEqual(210L , message.GetExtension(UnitTestProtoFile.RepeatedSfixed64Extension, 0));
+    Assert.AreEqual(211F , message.GetExtension(UnitTestProtoFile.RepeatedFloatExtension   , 0));
+    Assert.AreEqual(212D , message.GetExtension(UnitTestProtoFile.RepeatedDoubleExtension  , 0));
+    Assert.AreEqual(true , message.GetExtension(UnitTestProtoFile.RepeatedBoolExtension    , 0));
+    Assert.AreEqual("215", message.GetExtension(UnitTestProtoFile.RepeatedStringExtension  , 0));
+    Assert.AreEqual(ToBytes("216"), message.GetExtension(UnitTestProtoFile.RepeatedBytesExtension, 0));
+
+    Assert.AreEqual(217, message.GetExtension(UnitTestProtoFile.RepeatedGroupExtension         , 0).A);
+    Assert.AreEqual(218, message.GetExtension(UnitTestProtoFile.RepeatedNestedMessageExtension , 0).Bb);
+    Assert.AreEqual(219, message.GetExtension(UnitTestProtoFile.RepeatedForeignMessageExtension, 0).C);
+    Assert.AreEqual(220, message.GetExtension(UnitTestProtoFile.RepeatedImportMessageExtension , 0).D);
+
+    Assert.AreEqual(TestAllTypes.Types.NestedEnum.BAR, message.GetExtension(UnitTestProtoFile.RepeatedNestedEnumExtension, 0));
+    Assert.AreEqual(ForeignEnum.FOREIGN_BAR, message.GetExtension(UnitTestProtoFile.RepeatedForeignEnumExtension, 0));
+    Assert.AreEqual(ImportEnum.IMPORT_BAR, message.GetExtension(UnitTestProtoFile.RepeatedImportEnumExtension, 0));
+
+    Assert.AreEqual("224", message.GetExtension(UnitTestProtoFile.RepeatedStringPieceExtension, 0));
+    Assert.AreEqual("225", message.GetExtension(UnitTestProtoFile.RepeatedCordExtension, 0));
+
+    Assert.AreEqual(301  , message.GetExtension(UnitTestProtoFile.RepeatedInt32Extension   , 1));
+    Assert.AreEqual(302L , message.GetExtension(UnitTestProtoFile.RepeatedInt64Extension   , 1));
+    Assert.AreEqual(303U  , message.GetExtension(UnitTestProtoFile.RepeatedUint32Extension  , 1));
+    Assert.AreEqual(304UL , message.GetExtension(UnitTestProtoFile.RepeatedUint64Extension  , 1));
+    Assert.AreEqual(305  , message.GetExtension(UnitTestProtoFile.RepeatedSint32Extension  , 1));
+    Assert.AreEqual(306L , message.GetExtension(UnitTestProtoFile.RepeatedSint64Extension  , 1));
+    Assert.AreEqual(307U  , message.GetExtension(UnitTestProtoFile.RepeatedFixed32Extension , 1));
+    Assert.AreEqual(308UL , message.GetExtension(UnitTestProtoFile.RepeatedFixed64Extension , 1));
+    Assert.AreEqual(309  , message.GetExtension(UnitTestProtoFile.RepeatedSfixed32Extension, 1));
+    Assert.AreEqual(310L , message.GetExtension(UnitTestProtoFile.RepeatedSfixed64Extension, 1));
+    Assert.AreEqual(311F , message.GetExtension(UnitTestProtoFile.RepeatedFloatExtension   , 1));
+    Assert.AreEqual(312D , message.GetExtension(UnitTestProtoFile.RepeatedDoubleExtension  , 1));
+    Assert.AreEqual(false, message.GetExtension(UnitTestProtoFile.RepeatedBoolExtension    , 1));
+    Assert.AreEqual("315", message.GetExtension(UnitTestProtoFile.RepeatedStringExtension  , 1));
+    Assert.AreEqual(ToBytes("316"), message.GetExtension(UnitTestProtoFile.RepeatedBytesExtension, 1));
+
+    Assert.AreEqual(317, message.GetExtension(UnitTestProtoFile.RepeatedGroupExtension         , 1).A);
+    Assert.AreEqual(318, message.GetExtension(UnitTestProtoFile.RepeatedNestedMessageExtension , 1).Bb);
+    Assert.AreEqual(319, message.GetExtension(UnitTestProtoFile.RepeatedForeignMessageExtension, 1).C);
+    Assert.AreEqual(320, message.GetExtension(UnitTestProtoFile.RepeatedImportMessageExtension , 1).D);
+
+    Assert.AreEqual(TestAllTypes.Types.NestedEnum.BAZ, message.GetExtension(UnitTestProtoFile.RepeatedNestedEnumExtension, 1));
+    Assert.AreEqual(ForeignEnum.FOREIGN_BAZ, message.GetExtension(UnitTestProtoFile.RepeatedForeignEnumExtension, 1));
+    Assert.AreEqual(ImportEnum.IMPORT_BAZ, message.GetExtension(UnitTestProtoFile.RepeatedImportEnumExtension, 1));
+
+    Assert.AreEqual("324", message.GetExtension(UnitTestProtoFile.RepeatedStringPieceExtension, 1));
+    Assert.AreEqual("325", message.GetExtension(UnitTestProtoFile.RepeatedCordExtension, 1));
+
+    // -----------------------------------------------------------------
+
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultInt32Extension   ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultInt64Extension   ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultUint32Extension  ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultUint64Extension  ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultSint32Extension  ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultSint64Extension  ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultFixed32Extension ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultFixed64Extension ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultSfixed32Extension));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultSfixed64Extension));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultFloatExtension   ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultDoubleExtension  ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultBoolExtension    ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultStringExtension  ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultBytesExtension   ));
+
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultNestedEnumExtension ));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultForeignEnumExtension));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultImportEnumExtension ));
+
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultStringPieceExtension));
+    Assert.IsTrue(message.HasExtension(UnitTestProtoFile.DefaultCordExtension));
+
+    Assert.AreEqual(401  , message.GetExtension(UnitTestProtoFile.DefaultInt32Extension   ));
+    Assert.AreEqual(402L , message.GetExtension(UnitTestProtoFile.DefaultInt64Extension   ));
+    Assert.AreEqual(403U  , message.GetExtension(UnitTestProtoFile.DefaultUint32Extension  ));
+    Assert.AreEqual(404UL , message.GetExtension(UnitTestProtoFile.DefaultUint64Extension  ));
+    Assert.AreEqual(405  , message.GetExtension(UnitTestProtoFile.DefaultSint32Extension  ));
+    Assert.AreEqual(406L , message.GetExtension(UnitTestProtoFile.DefaultSint64Extension  ));
+    Assert.AreEqual(407U  , message.GetExtension(UnitTestProtoFile.DefaultFixed32Extension ));
+    Assert.AreEqual(408UL , message.GetExtension(UnitTestProtoFile.DefaultFixed64Extension ));
+    Assert.AreEqual(409  , message.GetExtension(UnitTestProtoFile.DefaultSfixed32Extension));
+    Assert.AreEqual(410L , message.GetExtension(UnitTestProtoFile.DefaultSfixed64Extension));
+    Assert.AreEqual(411F , message.GetExtension(UnitTestProtoFile.DefaultFloatExtension   ));
+    Assert.AreEqual(412D , message.GetExtension(UnitTestProtoFile.DefaultDoubleExtension  ));
+    Assert.AreEqual(false, message.GetExtension(UnitTestProtoFile.DefaultBoolExtension    ));
+    Assert.AreEqual("415", message.GetExtension(UnitTestProtoFile.DefaultStringExtension  ));
+    Assert.AreEqual(ToBytes("416"), message.GetExtension(UnitTestProtoFile.DefaultBytesExtension));
+
+    Assert.AreEqual(TestAllTypes.Types.NestedEnum.FOO, message.GetExtension(UnitTestProtoFile.DefaultNestedEnumExtension ));
+    Assert.AreEqual(ForeignEnum.FOREIGN_FOO, message.GetExtension(UnitTestProtoFile.DefaultForeignEnumExtension));
+    Assert.AreEqual(ImportEnum.IMPORT_FOO, message.GetExtension(UnitTestProtoFile.DefaultImportEnumExtension));
+
+    Assert.AreEqual("424", message.GetExtension(UnitTestProtoFile.DefaultStringPieceExtension));
+    Assert.AreEqual("425", message.GetExtension(UnitTestProtoFile.DefaultCordExtension));
+    }
+
+    /// <summary>
+    /// Modifies the repeated extensions of the given message to contain the values
+    /// expected by AssertRepeatedExtensionsModified.
+    /// </summary>
+    public static void ModifyRepeatedExtensions(TestAllExtensions.Builder message) {
+      message.SetExtension(UnitTestProtoFile.RepeatedInt32Extension, 1, 501);
+      message.SetExtension(UnitTestProtoFile.RepeatedInt64Extension, 1, 502L);
+      message.SetExtension(UnitTestProtoFile.RepeatedUint32Extension, 1, 503U);
+      message.SetExtension(UnitTestProtoFile.RepeatedUint64Extension, 1, 504UL);
+      message.SetExtension(UnitTestProtoFile.RepeatedSint32Extension, 1, 505);
+      message.SetExtension(UnitTestProtoFile.RepeatedSint64Extension, 1, 506L);
+      message.SetExtension(UnitTestProtoFile.RepeatedFixed32Extension, 1, 507U);
+      message.SetExtension(UnitTestProtoFile.RepeatedFixed64Extension, 1, 508UL);
+      message.SetExtension(UnitTestProtoFile.RepeatedSfixed32Extension, 1, 509);
+      message.SetExtension(UnitTestProtoFile.RepeatedSfixed64Extension, 1, 510L);
+      message.SetExtension(UnitTestProtoFile.RepeatedFloatExtension, 1, 511F);
+      message.SetExtension(UnitTestProtoFile.RepeatedDoubleExtension, 1, 512D);
+      message.SetExtension(UnitTestProtoFile.RepeatedBoolExtension, 1, true);
+      message.SetExtension(UnitTestProtoFile.RepeatedStringExtension, 1, "515");
+      message.SetExtension(UnitTestProtoFile.RepeatedBytesExtension, 1, ToBytes("516"));
+
+      message.SetExtension(UnitTestProtoFile.RepeatedGroupExtension, 1, RepeatedGroup_extension.CreateBuilder().SetA(517).Build());
+      message.SetExtension(UnitTestProtoFile.RepeatedNestedMessageExtension, 1, TestAllTypes.Types.NestedMessage.CreateBuilder().SetBb(518).Build());
+      message.SetExtension(UnitTestProtoFile.RepeatedForeignMessageExtension, 1, ForeignMessage.CreateBuilder().SetC(519).Build());
+      message.SetExtension(UnitTestProtoFile.RepeatedImportMessageExtension, 1, ImportMessage.CreateBuilder().SetD(520).Build());
+
+      message.SetExtension(UnitTestProtoFile.RepeatedNestedEnumExtension, 1, TestAllTypes.Types.NestedEnum.FOO);
+      message.SetExtension(UnitTestProtoFile.RepeatedForeignEnumExtension, 1, ForeignEnum.FOREIGN_FOO);
+      message.SetExtension(UnitTestProtoFile.RepeatedImportEnumExtension, 1, ImportEnum.IMPORT_FOO);
+
+      message.SetExtension(UnitTestProtoFile.RepeatedStringPieceExtension, 1, "524");
+      message.SetExtension(UnitTestProtoFile.RepeatedCordExtension, 1, "525");
+    }
+
+    /// <summary>
+    /// Asserts that all repeated extensions are set to the values assigned by
+    /// SetAllExtensions follwed by ModifyRepeatedExtensions.
+    /// </summary>
+    public static void AssertRepeatedExtensionsModified(TestAllExtensions message) {
+      // ModifyRepeatedFields only sets the second repeated element of each
+      // field.  In addition to verifying this, we also verify that the first
+      // element and size were *not* modified.
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedInt32Extension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedInt64Extension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedUint32Extension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedUint64Extension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedSint32Extension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedSint64Extension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedFixed32Extension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedFixed64Extension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedSfixed32Extension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedSfixed64Extension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedFloatExtension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedDoubleExtension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedBoolExtension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedStringExtension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedBytesExtension));
+
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedGroupExtension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedNestedMessageExtension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedForeignMessageExtension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedImportMessageExtension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedNestedEnumExtension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedForeignEnumExtension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedImportEnumExtension));
+
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedStringPieceExtension));
+      Assert.AreEqual(2, message.GetExtensionCount(UnitTestProtoFile.RepeatedCordExtension));
+
+      Assert.AreEqual(201, message.GetExtension(UnitTestProtoFile.RepeatedInt32Extension, 0));
+      Assert.AreEqual(202L, message.GetExtension(UnitTestProtoFile.RepeatedInt64Extension, 0));
+      Assert.AreEqual(203U, message.GetExtension(UnitTestProtoFile.RepeatedUint32Extension, 0));
+      Assert.AreEqual(204UL, message.GetExtension(UnitTestProtoFile.RepeatedUint64Extension, 0));
+      Assert.AreEqual(205, message.GetExtension(UnitTestProtoFile.RepeatedSint32Extension, 0));
+      Assert.AreEqual(206L, message.GetExtension(UnitTestProtoFile.RepeatedSint64Extension, 0));
+      Assert.AreEqual(207U, message.GetExtension(UnitTestProtoFile.RepeatedFixed32Extension, 0));
+      Assert.AreEqual(208UL, message.GetExtension(UnitTestProtoFile.RepeatedFixed64Extension, 0));
+      Assert.AreEqual(209, message.GetExtension(UnitTestProtoFile.RepeatedSfixed32Extension, 0));
+      Assert.AreEqual(210L, message.GetExtension(UnitTestProtoFile.RepeatedSfixed64Extension, 0));
+      Assert.AreEqual(211F, message.GetExtension(UnitTestProtoFile.RepeatedFloatExtension, 0));
+      Assert.AreEqual(212D, message.GetExtension(UnitTestProtoFile.RepeatedDoubleExtension, 0));
+      Assert.AreEqual(true, message.GetExtension(UnitTestProtoFile.RepeatedBoolExtension, 0));
+      Assert.AreEqual("215", message.GetExtension(UnitTestProtoFile.RepeatedStringExtension, 0));
+      Assert.AreEqual(ToBytes("216"), message.GetExtension(UnitTestProtoFile.RepeatedBytesExtension, 0));
+
+      Assert.AreEqual(217, message.GetExtension(UnitTestProtoFile.RepeatedGroupExtension, 0).A);
+      Assert.AreEqual(218, message.GetExtension(UnitTestProtoFile.RepeatedNestedMessageExtension, 0).Bb);
+      Assert.AreEqual(219, message.GetExtension(UnitTestProtoFile.RepeatedForeignMessageExtension, 0).C);
+      Assert.AreEqual(220, message.GetExtension(UnitTestProtoFile.RepeatedImportMessageExtension, 0).D);
+
+      Assert.AreEqual(TestAllTypes.Types.NestedEnum.BAR, message.GetExtension(UnitTestProtoFile.RepeatedNestedEnumExtension, 0));
+      Assert.AreEqual(ForeignEnum.FOREIGN_BAR, message.GetExtension(UnitTestProtoFile.RepeatedForeignEnumExtension, 0));
+      Assert.AreEqual(ImportEnum.IMPORT_BAR, message.GetExtension(UnitTestProtoFile.RepeatedImportEnumExtension, 0));
+
+      Assert.AreEqual("224", message.GetExtension(UnitTestProtoFile.RepeatedStringPieceExtension, 0));
+      Assert.AreEqual("225", message.GetExtension(UnitTestProtoFile.RepeatedCordExtension, 0));
+
+      // Actually verify the second (modified) elements now.
+      Assert.AreEqual(501, message.GetExtension(UnitTestProtoFile.RepeatedInt32Extension, 1));
+      Assert.AreEqual(502L, message.GetExtension(UnitTestProtoFile.RepeatedInt64Extension, 1));
+      Assert.AreEqual(503U, message.GetExtension(UnitTestProtoFile.RepeatedUint32Extension, 1));
+      Assert.AreEqual(504UL, message.GetExtension(UnitTestProtoFile.RepeatedUint64Extension, 1));
+      Assert.AreEqual(505, message.GetExtension(UnitTestProtoFile.RepeatedSint32Extension, 1));
+      Assert.AreEqual(506L, message.GetExtension(UnitTestProtoFile.RepeatedSint64Extension, 1));
+      Assert.AreEqual(507U, message.GetExtension(UnitTestProtoFile.RepeatedFixed32Extension, 1));
+      Assert.AreEqual(508UL, message.GetExtension(UnitTestProtoFile.RepeatedFixed64Extension, 1));
+      Assert.AreEqual(509, message.GetExtension(UnitTestProtoFile.RepeatedSfixed32Extension, 1));
+      Assert.AreEqual(510L, message.GetExtension(UnitTestProtoFile.RepeatedSfixed64Extension, 1));
+      Assert.AreEqual(511F, message.GetExtension(UnitTestProtoFile.RepeatedFloatExtension, 1));
+      Assert.AreEqual(512D, message.GetExtension(UnitTestProtoFile.RepeatedDoubleExtension, 1));
+      Assert.AreEqual(true, message.GetExtension(UnitTestProtoFile.RepeatedBoolExtension, 1));
+      Assert.AreEqual("515", message.GetExtension(UnitTestProtoFile.RepeatedStringExtension, 1));
+      Assert.AreEqual(ToBytes("516"), message.GetExtension(UnitTestProtoFile.RepeatedBytesExtension, 1));
+
+      Assert.AreEqual(517, message.GetExtension(UnitTestProtoFile.RepeatedGroupExtension, 1).A);
+      Assert.AreEqual(518, message.GetExtension(UnitTestProtoFile.RepeatedNestedMessageExtension, 1).Bb);
+      Assert.AreEqual(519, message.GetExtension(UnitTestProtoFile.RepeatedForeignMessageExtension, 1).C);
+      Assert.AreEqual(520, message.GetExtension(UnitTestProtoFile.RepeatedImportMessageExtension, 1).D);
+
+      Assert.AreEqual(TestAllTypes.Types.NestedEnum.FOO, message.GetExtension(UnitTestProtoFile.RepeatedNestedEnumExtension, 1));
+      Assert.AreEqual(ForeignEnum.FOREIGN_FOO, message.GetExtension(UnitTestProtoFile.RepeatedForeignEnumExtension, 1));
+      Assert.AreEqual(ImportEnum.IMPORT_FOO, message.GetExtension(UnitTestProtoFile.RepeatedImportEnumExtension, 1));
+
+      Assert.AreEqual("524", message.GetExtension(UnitTestProtoFile.RepeatedStringPieceExtension, 1));
+      Assert.AreEqual("525", message.GetExtension(UnitTestProtoFile.RepeatedCordExtension, 1));
+    }
+
+    public static void AssertExtensionsClear(TestAllExtensions message) {
+      // HasBlah() should initially be false for all optional fields.
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalInt32Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalInt64Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalUint32Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalUint64Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalSint32Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalSint64Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalFixed32Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalFixed64Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalSfixed32Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalSfixed64Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalFloatExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalDoubleExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalBoolExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalStringExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalBytesExtension));
+
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalGroupExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalNestedMessageExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalForeignMessageExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalImportMessageExtension));
+
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalNestedEnumExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalForeignEnumExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalImportEnumExtension));
+
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalStringPieceExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.OptionalCordExtension));
+
+      // Optional fields without defaults are set to zero or something like it.
+      Assert.AreEqual(0, message.GetExtension(UnitTestProtoFile.OptionalInt32Extension));
+      Assert.AreEqual(0L, message.GetExtension(UnitTestProtoFile.OptionalInt64Extension));
+      Assert.AreEqual(0U, message.GetExtension(UnitTestProtoFile.OptionalUint32Extension));
+      Assert.AreEqual(0UL, message.GetExtension(UnitTestProtoFile.OptionalUint64Extension));
+      Assert.AreEqual(0, message.GetExtension(UnitTestProtoFile.OptionalSint32Extension));
+      Assert.AreEqual(0L, message.GetExtension(UnitTestProtoFile.OptionalSint64Extension));
+      Assert.AreEqual(0U, message.GetExtension(UnitTestProtoFile.OptionalFixed32Extension));
+      Assert.AreEqual(0UL, message.GetExtension(UnitTestProtoFile.OptionalFixed64Extension));
+      Assert.AreEqual(0, message.GetExtension(UnitTestProtoFile.OptionalSfixed32Extension));
+      Assert.AreEqual(0L, message.GetExtension(UnitTestProtoFile.OptionalSfixed64Extension));
+      Assert.AreEqual(0F, message.GetExtension(UnitTestProtoFile.OptionalFloatExtension));
+      Assert.AreEqual(0D, message.GetExtension(UnitTestProtoFile.OptionalDoubleExtension));
+      Assert.AreEqual(false, message.GetExtension(UnitTestProtoFile.OptionalBoolExtension));
+      Assert.AreEqual("", message.GetExtension(UnitTestProtoFile.OptionalStringExtension));
+      Assert.AreEqual(ByteString.Empty, message.GetExtension(UnitTestProtoFile.OptionalBytesExtension));
+
+      // Embedded messages should also be clear.
+      Assert.IsFalse(message.GetExtension(UnitTestProtoFile.OptionalGroupExtension).HasA);
+      Assert.IsFalse(message.GetExtension(UnitTestProtoFile.OptionalNestedMessageExtension).HasBb);
+      Assert.IsFalse(message.GetExtension(UnitTestProtoFile.OptionalForeignMessageExtension).HasC);
+      Assert.IsFalse(message.GetExtension(UnitTestProtoFile.OptionalImportMessageExtension).HasD);
+
+      Assert.AreEqual(0, message.GetExtension(UnitTestProtoFile.OptionalGroupExtension).A);
+      Assert.AreEqual(0, message.GetExtension(UnitTestProtoFile.OptionalNestedMessageExtension).Bb);
+      Assert.AreEqual(0, message.GetExtension(UnitTestProtoFile.OptionalForeignMessageExtension).C);
+      Assert.AreEqual(0, message.GetExtension(UnitTestProtoFile.OptionalImportMessageExtension).D);
+
+      // Enums without defaults are set to the first value in the enum.
+      Assert.AreEqual(TestAllTypes.Types.NestedEnum.FOO, message.GetExtension(UnitTestProtoFile.OptionalNestedEnumExtension));
+      Assert.AreEqual(ForeignEnum.FOREIGN_FOO, message.GetExtension(UnitTestProtoFile.OptionalForeignEnumExtension));
+      Assert.AreEqual(ImportEnum.IMPORT_FOO, message.GetExtension(UnitTestProtoFile.OptionalImportEnumExtension));
+
+      Assert.AreEqual("", message.GetExtension(UnitTestProtoFile.OptionalStringPieceExtension));
+      Assert.AreEqual("", message.GetExtension(UnitTestProtoFile.OptionalCordExtension));
+
+      // Repeated fields are empty.
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedInt32Extension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedInt64Extension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedUint32Extension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedUint64Extension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedSint32Extension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedSint64Extension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedFixed32Extension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedFixed64Extension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedSfixed32Extension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedSfixed64Extension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedFloatExtension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedDoubleExtension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedBoolExtension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedStringExtension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedBytesExtension));
+
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedGroupExtension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedNestedMessageExtension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedForeignMessageExtension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedImportMessageExtension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedNestedEnumExtension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedForeignEnumExtension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedImportEnumExtension));
+
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedStringPieceExtension));
+      Assert.AreEqual(0, message.GetExtensionCount(UnitTestProtoFile.RepeatedCordExtension));
+
+      // HasBlah() should also be false for all default fields.
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultInt32Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultInt64Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultUint32Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultUint64Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultSint32Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultSint64Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultFixed32Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultFixed64Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultSfixed32Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultSfixed64Extension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultFloatExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultDoubleExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultBoolExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultStringExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultBytesExtension));
+
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultNestedEnumExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultForeignEnumExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultImportEnumExtension));
+
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultStringPieceExtension));
+      Assert.IsFalse(message.HasExtension(UnitTestProtoFile.DefaultCordExtension));
+
+      // Fields with defaults have their default values (duh).
+      Assert.AreEqual(41, message.GetExtension(UnitTestProtoFile.DefaultInt32Extension));
+      Assert.AreEqual(42L, message.GetExtension(UnitTestProtoFile.DefaultInt64Extension));
+      Assert.AreEqual(43U, message.GetExtension(UnitTestProtoFile.DefaultUint32Extension));
+      Assert.AreEqual(44UL, message.GetExtension(UnitTestProtoFile.DefaultUint64Extension));
+      Assert.AreEqual(-45, message.GetExtension(UnitTestProtoFile.DefaultSint32Extension));
+      Assert.AreEqual(46L, message.GetExtension(UnitTestProtoFile.DefaultSint64Extension));
+      Assert.AreEqual(47U, message.GetExtension(UnitTestProtoFile.DefaultFixed32Extension));
+      Assert.AreEqual(48UL, message.GetExtension(UnitTestProtoFile.DefaultFixed64Extension));
+      Assert.AreEqual(49, message.GetExtension(UnitTestProtoFile.DefaultSfixed32Extension));
+      Assert.AreEqual(-50L, message.GetExtension(UnitTestProtoFile.DefaultSfixed64Extension));
+      Assert.AreEqual(51.5F, message.GetExtension(UnitTestProtoFile.DefaultFloatExtension));
+      Assert.AreEqual(52e3D, message.GetExtension(UnitTestProtoFile.DefaultDoubleExtension));
+      Assert.AreEqual(true, message.GetExtension(UnitTestProtoFile.DefaultBoolExtension));
+      Assert.AreEqual("hello", message.GetExtension(UnitTestProtoFile.DefaultStringExtension));
+      Assert.AreEqual(ToBytes("world"), message.GetExtension(UnitTestProtoFile.DefaultBytesExtension));
+
+      Assert.AreEqual(TestAllTypes.Types.NestedEnum.BAR, message.GetExtension(UnitTestProtoFile.DefaultNestedEnumExtension));
+      Assert.AreEqual(ForeignEnum.FOREIGN_BAR, message.GetExtension(UnitTestProtoFile.DefaultForeignEnumExtension));
+      Assert.AreEqual(ImportEnum.IMPORT_BAR, message.GetExtension(UnitTestProtoFile.DefaultImportEnumExtension));
+
+      Assert.AreEqual("abc", message.GetExtension(UnitTestProtoFile.DefaultStringPieceExtension));
+      Assert.AreEqual("123", message.GetExtension(UnitTestProtoFile.DefaultCordExtension));
+    }
   }
 }
diff --git a/csharp/ProtocolBuffers/ExtendableBuilder.cs b/csharp/ProtocolBuffers/ExtendableBuilder.cs
index 3f5a8162..0c96ace6 100644
--- a/csharp/ProtocolBuffers/ExtendableBuilder.cs
+++ b/csharp/ProtocolBuffers/ExtendableBuilder.cs
@@ -52,7 +52,7 @@ namespace Google.ProtocolBuffers {
     /// Sets the value of one element of a repeated extension.
     /// </summary>
     public ExtendableBuilder<TMessage, TBuilder> SetExtension<TExtension>(
-        GeneratedExtensionBase<TMessage, IList<TExtension>> extension, int index, Type value) {
+        GeneratedExtensionBase<TMessage, IList<TExtension>> extension, int index, TExtension value) {
       ExtendableMessage<TMessage, TBuilder> message = MessageBeingBuilt;
       message.VerifyExtensionContainingType(extension);
       message.Extensions[extension.Descriptor, index] = extension.SingularToReflectionType(value);
@@ -118,7 +118,6 @@ namespace Google.ProtocolBuffers {
         } else {
           base[field] = value;
         }
-        InternalFieldAccessors[field].SetValue(this, value);
       }
     }