Minor cleanup.

- Make some members internal
- Remove a lot of FrameworkPortability that isn't required
- Start adding documentation comments
- Remove some more group-based members
- Not passing in "the last tag read" into Read*Array, g

18 files changed, 256 insertions, 254 deletions

diff --git a/csharp/src/AddressBook/Addressbook.cs b/csharp/src/AddressBook/Addressbook.cs
index 480fb92a..322f85f7 100644
--- a/csharp/src/AddressBook/Addressbook.cs
+++ b/csharp/src/AddressBook/Addressbook.cs
@@ -214,7 +214,7 @@ namespace Google.ProtocolBuffers.Examples.AddressBook {
             break;
           }
           case 34: {
-            input.ReadMessageArray(tag, phone_, global::Google.ProtocolBuffers.Examples.AddressBook.Person.Types.PhoneNumber.Parser);
+            input.ReadMessageArray(phone_, global::Google.ProtocolBuffers.Examples.AddressBook.Person.Types.PhoneNumber.Parser);
             break;
           }
         }
@@ -432,7 +432,7 @@ namespace Google.ProtocolBuffers.Examples.AddressBook {
             }
             break;
           case 10: {
-            input.ReadMessageArray(tag, person_, global::Google.ProtocolBuffers.Examples.AddressBook.Person.Parser);
+            input.ReadMessageArray(person_, global::Google.ProtocolBuffers.Examples.AddressBook.Person.Parser);
             break;
           }
         }
diff --git a/csharp/src/ProtocolBuffers.Test/CodedInputStreamTest.cs b/csharp/src/ProtocolBuffers.Test/CodedInputStreamTest.cs
index 0baa3a75..52757d4d 100644
--- a/csharp/src/ProtocolBuffers.Test/CodedInputStreamTest.cs
+++ b/csharp/src/ProtocolBuffers.Test/CodedInputStreamTest.cs
@@ -489,7 +489,7 @@ namespace Google.Protobuf
             Assert.IsTrue(input.ReadTag(out tag));

 

             RepeatedField<TestNegEnum> values = new RepeatedField<TestNegEnum>();

-            input.ReadEnumArray(tag, values);

+            input.ReadEnumArray(values);

 

             Assert.AreEqual(6, values.Count);

             Assert.AreEqual(TestNegEnum.None, values[0]);

@@ -513,7 +513,7 @@ namespace Google.Protobuf
             Assert.IsTrue(input.ReadTag(out tag));

 

             RepeatedField<TestNegEnum> values = new RepeatedField<TestNegEnum>();

-            input.ReadEnumArray(tag, values);

+            input.ReadEnumArray(values);

 

             Assert.AreEqual(6, values.Count);

             Assert.AreEqual(TestNegEnum.None, values[0]);

diff --git a/csharp/src/ProtocolBuffers.Test/CodedOutputStreamTest.cs b/csharp/src/ProtocolBuffers.Test/CodedOutputStreamTest.cs
index bc053e19..223374e0 100644
--- a/csharp/src/ProtocolBuffers.Test/CodedOutputStreamTest.cs
+++ b/csharp/src/ProtocolBuffers.Test/CodedOutputStreamTest.cs
@@ -326,7 +326,7 @@ namespace Google.Protobuf
             Assert.IsTrue(input.ReadTag(out tag));

 

             List<int> values = new List<int>();

-            input.ReadInt32Array(tag, values);

+            input.ReadInt32Array(values);

 

             Assert.AreEqual(6, values.Count);

             for (int i = 0; i > -6; i--)

@@ -349,7 +349,7 @@ namespace Google.Protobuf
             Assert.IsTrue(input.ReadTag(out tag));

 

             List<int> values = new List<int>();

-            input.ReadInt32Array(tag, values);

+            input.ReadInt32Array(values);

 

             Assert.AreEqual(6, values.Count);

             for (int i = 0; i > -6; i--)

diff --git a/csharp/src/ProtocolBuffers.Test/TestProtos/UnittestIssues.cs b/csharp/src/ProtocolBuffers.Test/TestProtos/UnittestIssues.cs
index 1ea3728d..959b3866 100644
--- a/csharp/src/ProtocolBuffers.Test/TestProtos/UnittestIssues.cs
+++ b/csharp/src/ProtocolBuffers.Test/TestProtos/UnittestIssues.cs
@@ -218,12 +218,12 @@ namespace UnitTest.Issues.TestProtos {
           }
           case 18:
           case 16: {
-            input.ReadEnumArray<global::UnitTest.Issues.TestProtos.NegativeEnum>(tag, values_);
+            input.ReadEnumArray<global::UnitTest.Issues.TestProtos.NegativeEnum>(values_);
             break;
           }
           case 26:
           case 24: {
-            input.ReadEnumArray<global::UnitTest.Issues.TestProtos.NegativeEnum>(tag, packedValues_);
+            input.ReadEnumArray<global::UnitTest.Issues.TestProtos.NegativeEnum>(packedValues_);
             break;
           }
         }
@@ -495,7 +495,7 @@ namespace UnitTest.Issues.TestProtos {
           }
           case 18:
           case 16: {
-            input.ReadInt32Array(tag, primitiveArray_);
+            input.ReadInt32Array(primitiveArray_);
             break;
           }
           case 26: {
@@ -506,7 +506,7 @@ namespace UnitTest.Issues.TestProtos {
             break;
           }
           case 34: {
-            input.ReadMessageArray(tag, messageArray_, global::UnitTest.Issues.TestProtos.DeprecatedChild.Parser);
+            input.ReadMessageArray(messageArray_, global::UnitTest.Issues.TestProtos.DeprecatedChild.Parser);
             break;
           }
           case 40: {
@@ -515,7 +515,7 @@ namespace UnitTest.Issues.TestProtos {
           }
           case 50:
           case 48: {
-            input.ReadEnumArray<global::UnitTest.Issues.TestProtos.DeprecatedEnum>(tag, enumArray_);
+            input.ReadEnumArray<global::UnitTest.Issues.TestProtos.DeprecatedEnum>(enumArray_);
             break;
           }
         }
diff --git a/csharp/src/ProtocolBuffers.Test/TestProtos/UnittestProto3.cs b/csharp/src/ProtocolBuffers.Test/TestProtos/UnittestProto3.cs
index a2c5d5f6..bbfa8c3e 100644
--- a/csharp/src/ProtocolBuffers.Test/TestProtos/UnittestProto3.cs
+++ b/csharp/src/ProtocolBuffers.Test/TestProtos/UnittestProto3.cs
@@ -1547,106 +1547,106 @@ namespace Google.Protobuf.TestProtos {
           }
           case 250:
           case 248: {
-            input.ReadInt32Array(tag, repeatedInt32_);
+            input.ReadInt32Array(repeatedInt32_);
             break;
           }
           case 258:
           case 256: {
-            input.ReadInt64Array(tag, repeatedInt64_);
+            input.ReadInt64Array(repeatedInt64_);
             break;
           }
           case 266:
           case 264: {
-            input.ReadUInt32Array(tag, repeatedUint32_);
+            input.ReadUInt32Array(repeatedUint32_);
             break;
           }
           case 274:
           case 272: {
-            input.ReadUInt64Array(tag, repeatedUint64_);
+            input.ReadUInt64Array(repeatedUint64_);
             break;
           }
           case 282:
           case 280: {
-            input.ReadSInt32Array(tag, repeatedSint32_);
+            input.ReadSInt32Array(repeatedSint32_);
             break;
           }
           case 290:
           case 288: {
-            input.ReadSInt64Array(tag, repeatedSint64_);
+            input.ReadSInt64Array(repeatedSint64_);
             break;
           }
           case 298:
           case 301: {
-            input.ReadFixed32Array(tag, repeatedFixed32_);
+            input.ReadFixed32Array(repeatedFixed32_);
             break;
           }
           case 306:
           case 305: {
-            input.ReadFixed64Array(tag, repeatedFixed64_);
+            input.ReadFixed64Array(repeatedFixed64_);
             break;
           }
           case 314:
           case 317: {
-            input.ReadSFixed32Array(tag, repeatedSfixed32_);
+            input.ReadSFixed32Array(repeatedSfixed32_);
             break;
           }
           case 322:
           case 321: {
-            input.ReadSFixed64Array(tag, repeatedSfixed64_);
+            input.ReadSFixed64Array(repeatedSfixed64_);
             break;
           }
           case 330:
           case 333: {
-            input.ReadFloatArray(tag, repeatedFloat_);
+            input.ReadFloatArray(repeatedFloat_);
             break;
           }
           case 338:
           case 337: {
-            input.ReadDoubleArray(tag, repeatedDouble_);
+            input.ReadDoubleArray(repeatedDouble_);
             break;
           }
           case 346:
           case 344: {
-            input.ReadBoolArray(tag, repeatedBool_);
+            input.ReadBoolArray(repeatedBool_);
             break;
           }
           case 354: {
-            input.ReadStringArray(tag, repeatedString_);
+            input.ReadStringArray(repeatedString_);
             break;
           }
           case 362: {
-            input.ReadBytesArray(tag, repeatedBytes_);
+            input.ReadBytesArray(repeatedBytes_);
             break;
           }
           case 386: {
-            input.ReadMessageArray(tag, repeatedNestedMessage_, global::Google.Protobuf.TestProtos.TestAllTypes.Types.NestedMessage.Parser);
+            input.ReadMessageArray(repeatedNestedMessage_, global::Google.Protobuf.TestProtos.TestAllTypes.Types.NestedMessage.Parser);
             break;
           }
           case 394: {
-            input.ReadMessageArray(tag, repeatedForeignMessage_, global::Google.Protobuf.TestProtos.ForeignMessage.Parser);
+            input.ReadMessageArray(repeatedForeignMessage_, global::Google.Protobuf.TestProtos.ForeignMessage.Parser);
             break;
           }
           case 402: {
-            input.ReadMessageArray(tag, repeatedImportMessage_, global::Google.Protobuf.TestProtos.ImportMessage.Parser);
+            input.ReadMessageArray(repeatedImportMessage_, global::Google.Protobuf.TestProtos.ImportMessage.Parser);
             break;
           }
           case 410:
           case 408: {
-            input.ReadEnumArray<global::Google.Protobuf.TestProtos.TestAllTypes.Types.NestedEnum>(tag, repeatedNestedEnum_);
+            input.ReadEnumArray<global::Google.Protobuf.TestProtos.TestAllTypes.Types.NestedEnum>(repeatedNestedEnum_);
             break;
           }
           case 418:
           case 416: {
-            input.ReadEnumArray<global::Google.Protobuf.TestProtos.ForeignEnum>(tag, repeatedForeignEnum_);
+            input.ReadEnumArray<global::Google.Protobuf.TestProtos.ForeignEnum>(repeatedForeignEnum_);
             break;
           }
           case 426:
           case 424: {
-            input.ReadEnumArray<global::Google.Protobuf.TestProtos.ImportEnum>(tag, repeatedImportEnum_);
+            input.ReadEnumArray<global::Google.Protobuf.TestProtos.ImportEnum>(repeatedImportEnum_);
             break;
           }
           case 434: {
-            input.ReadMessageArray(tag, repeatedPublicImportMessage_, global::Google.Protobuf.TestProtos.PublicImportMessage.Parser);
+            input.ReadMessageArray(repeatedPublicImportMessage_, global::Google.Protobuf.TestProtos.PublicImportMessage.Parser);
             break;
           }
           case 888: {
@@ -1919,7 +1919,7 @@ namespace Google.Protobuf.TestProtos {
             break;
           }
           case 26: {
-            input.ReadMessageArray(tag, repeatedChild_, global::Google.Protobuf.TestProtos.NestedTestAllTypes.Parser);
+            input.ReadMessageArray(repeatedChild_, global::Google.Protobuf.TestProtos.NestedTestAllTypes.Parser);
             break;
           }
         }
@@ -2973,20 +2973,20 @@ namespace Google.Protobuf.TestProtos {
           }
           case 58:
           case 56: {
-            input.ReadInt32Array(tag, repeatedPrimitiveField_);
+            input.ReadInt32Array(repeatedPrimitiveField_);
             break;
           }
           case 66: {
-            input.ReadStringArray(tag, repeatedStringField_);
+            input.ReadStringArray(repeatedStringField_);
             break;
           }
           case 74:
           case 72: {
-            input.ReadEnumArray<global::Google.Protobuf.TestProtos.ForeignEnum>(tag, repeatedEnumField_);
+            input.ReadEnumArray<global::Google.Protobuf.TestProtos.ForeignEnum>(repeatedEnumField_);
             break;
           }
           case 82: {
-            input.ReadMessageArray(tag, repeatedMessageField_, global::Google.Protobuf.TestProtos.ForeignMessage.Parser);
+            input.ReadMessageArray(repeatedMessageField_, global::Google.Protobuf.TestProtos.ForeignMessage.Parser);
             break;
           }
         }
@@ -3552,7 +3552,7 @@ namespace Google.Protobuf.TestProtos {
             }
             break;
           case 10: {
-            input.ReadStringArray(tag, data_);
+            input.ReadStringArray(data_);
             break;
           }
         }
@@ -4716,72 +4716,72 @@ namespace Google.Protobuf.TestProtos {
             break;
           case 722:
           case 720: {
-            input.ReadInt32Array(tag, packedInt32_);
+            input.ReadInt32Array(packedInt32_);
             break;
           }
           case 730:
           case 728: {
-            input.ReadInt64Array(tag, packedInt64_);
+            input.ReadInt64Array(packedInt64_);
             break;
           }
           case 738:
           case 736: {
-            input.ReadUInt32Array(tag, packedUint32_);
+            input.ReadUInt32Array(packedUint32_);
             break;
           }
           case 746:
           case 744: {
-            input.ReadUInt64Array(tag, packedUint64_);
+            input.ReadUInt64Array(packedUint64_);
             break;
           }
           case 754:
           case 752: {
-            input.ReadSInt32Array(tag, packedSint32_);
+            input.ReadSInt32Array(packedSint32_);
             break;
           }
           case 762:
           case 760: {
-            input.ReadSInt64Array(tag, packedSint64_);
+            input.ReadSInt64Array(packedSint64_);
             break;
           }
           case 770:
           case 773: {
-            input.ReadFixed32Array(tag, packedFixed32_);
+            input.ReadFixed32Array(packedFixed32_);
             break;
           }
           case 778:
           case 777: {
-            input.ReadFixed64Array(tag, packedFixed64_);
+            input.ReadFixed64Array(packedFixed64_);
             break;
           }
           case 786:
           case 789: {
-            input.ReadSFixed32Array(tag, packedSfixed32_);
+            input.ReadSFixed32Array(packedSfixed32_);
             break;
           }
           case 794:
           case 793: {
-            input.ReadSFixed64Array(tag, packedSfixed64_);
+            input.ReadSFixed64Array(packedSfixed64_);
             break;
           }
           case 802:
           case 805: {
-            input.ReadFloatArray(tag, packedFloat_);
+            input.ReadFloatArray(packedFloat_);
             break;
           }
           case 810:
           case 809: {
-            input.ReadDoubleArray(tag, packedDouble_);
+            input.ReadDoubleArray(packedDouble_);
             break;
           }
           case 818:
           case 816: {
-            input.ReadBoolArray(tag, packedBool_);
+            input.ReadBoolArray(packedBool_);
             break;
           }
           case 826:
           case 824: {
-            input.ReadEnumArray<global::Google.Protobuf.TestProtos.ForeignEnum>(tag, packedEnum_);
+            input.ReadEnumArray<global::Google.Protobuf.TestProtos.ForeignEnum>(packedEnum_);
             break;
           }
         }
@@ -5120,72 +5120,72 @@ namespace Google.Protobuf.TestProtos {
             break;
           case 722:
           case 720: {
-            input.ReadInt32Array(tag, unpackedInt32_);
+            input.ReadInt32Array(unpackedInt32_);
             break;
           }
           case 730:
           case 728: {
-            input.ReadInt64Array(tag, unpackedInt64_);
+            input.ReadInt64Array(unpackedInt64_);
             break;
           }
           case 738:
           case 736: {
-            input.ReadUInt32Array(tag, unpackedUint32_);
+            input.ReadUInt32Array(unpackedUint32_);
             break;
           }
           case 746:
           case 744: {
-            input.ReadUInt64Array(tag, unpackedUint64_);
+            input.ReadUInt64Array(unpackedUint64_);
             break;
           }
           case 754:
           case 752: {
-            input.ReadSInt32Array(tag, unpackedSint32_);
+            input.ReadSInt32Array(unpackedSint32_);
             break;
           }
           case 762:
           case 760: {
-            input.ReadSInt64Array(tag, unpackedSint64_);
+            input.ReadSInt64Array(unpackedSint64_);
             break;
           }
           case 770:
           case 773: {
-            input.ReadFixed32Array(tag, unpackedFixed32_);
+            input.ReadFixed32Array(unpackedFixed32_);
             break;
           }
           case 778:
           case 777: {
-            input.ReadFixed64Array(tag, unpackedFixed64_);
+            input.ReadFixed64Array(unpackedFixed64_);
             break;
           }
           case 786:
           case 789: {
-            input.ReadSFixed32Array(tag, unpackedSfixed32_);
+            input.ReadSFixed32Array(unpackedSfixed32_);
             break;
           }
           case 794:
           case 793: {
-            input.ReadSFixed64Array(tag, unpackedSfixed64_);
+            input.ReadSFixed64Array(unpackedSfixed64_);
             break;
           }
           case 802:
           case 805: {
-            input.ReadFloatArray(tag, unpackedFloat_);
+            input.ReadFloatArray(unpackedFloat_);
             break;
           }
           case 810:
           case 809: {
-            input.ReadDoubleArray(tag, unpackedDouble_);
+            input.ReadDoubleArray(unpackedDouble_);
             break;
           }
           case 818:
           case 816: {
-            input.ReadBoolArray(tag, unpackedBool_);
+            input.ReadBoolArray(unpackedBool_);
             break;
           }
           case 826:
           case 824: {
-            input.ReadEnumArray<global::Google.Protobuf.TestProtos.ForeignEnum>(tag, unpackedEnum_);
+            input.ReadEnumArray<global::Google.Protobuf.TestProtos.ForeignEnum>(unpackedEnum_);
             break;
           }
         }
@@ -5378,32 +5378,32 @@ namespace Google.Protobuf.TestProtos {
             break;
           case 98:
           case 101: {
-            input.ReadFixed32Array(tag, repeatedFixed32_);
+            input.ReadFixed32Array(repeatedFixed32_);
             break;
           }
           case 106:
           case 104: {
-            input.ReadInt32Array(tag, repeatedInt32_);
+            input.ReadInt32Array(repeatedInt32_);
             break;
           }
           case 16370:
           case 16369: {
-            input.ReadFixed64Array(tag, repeatedFixed64_);
+            input.ReadFixed64Array(repeatedFixed64_);
             break;
           }
           case 16378:
           case 16376: {
-            input.ReadInt64Array(tag, repeatedInt64_);
+            input.ReadInt64Array(repeatedInt64_);
             break;
           }
           case 2097138:
           case 2097141: {
-            input.ReadFloatArray(tag, repeatedFloat_);
+            input.ReadFloatArray(repeatedFloat_);
             break;
           }
           case 2097146:
           case 2097144: {
-            input.ReadUInt64Array(tag, repeatedUint64_);
+            input.ReadUInt64Array(repeatedUint64_);
             break;
           }
         }
diff --git a/csharp/src/ProtocolBuffers/ByteArray.cs b/csharp/src/ProtocolBuffers/ByteArray.cs
index d367fc39..211a0e11 100644
--- a/csharp/src/ProtocolBuffers/ByteArray.cs
+++ b/csharp/src/ProtocolBuffers/ByteArray.cs
@@ -51,7 +51,7 @@ namespace Google.Protobuf
         /// <summary>

         /// Determines which copy routine to use based on the number of bytes to be copied.

         /// </summary>

-        public static void Copy(byte[] src, int srcOffset, byte[] dst, int dstOffset, int count)

+        internal static void Copy(byte[] src, int srcOffset, byte[] dst, int dstOffset, int count)

         {

             if (count > CopyThreshold)

             {

@@ -66,7 +66,7 @@ namespace Google.Protobuf
         /// <summary>

         /// Copy the bytes provided with a for loop, faster when there are only a few bytes to copy

         /// </summary>

-        public static void ByteCopy(byte[] src, int srcOffset, byte[] dst, int dstOffset, int count)

+        internal static void ByteCopy(byte[] src, int srcOffset, byte[] dst, int dstOffset, int count)

         {

             int stop = srcOffset + count;

             for (int i = srcOffset; i < stop; i++)

@@ -78,12 +78,11 @@ namespace Google.Protobuf
         /// <summary>

         /// Reverses the order of bytes in the array

         /// </summary>

-        public static void Reverse(byte[] bytes)

+        internal static void Reverse(byte[] bytes)

         {

-            byte temp;

             for (int first = 0, last = bytes.Length - 1; first < last; first++, last--)

             {

-                temp = bytes[first];

+                byte temp = bytes[first];

                 bytes[first] = bytes[last];

                 bytes[last] = temp;

             }

diff --git a/csharp/src/ProtocolBuffers/CodedInputStream.cs b/csharp/src/ProtocolBuffers/CodedInputStream.cs
index 56283318..905cdb9d 100644
--- a/csharp/src/ProtocolBuffers/CodedInputStream.cs
+++ b/csharp/src/ProtocolBuffers/CodedInputStream.cs
@@ -37,9 +37,7 @@
 using System;

 using System.Collections.Generic;

 using System.IO;

-using System.Text;

 using Google.Protobuf.Collections;

-using Google.Protobuf.Descriptors;

 

 namespace Google.Protobuf

 {

@@ -183,7 +181,7 @@ namespace Google.Protobuf
         /// </summary>

         /// <exception cref="InvalidProtocolBufferException">The last

         /// tag read was not the one specified</exception>

-        public void CheckLastTagWas(uint value)

+        internal void CheckLastTagWas(uint value)

         {

             if (lastTag != value)

             {

@@ -251,7 +249,7 @@ namespace Google.Protobuf
         /// </summary>

         public double ReadDouble()

         {

-            return FrameworkPortability.Int64ToDouble((long) ReadRawLittleEndian64());

+            return BitConverter.Int64BitsToDouble((long) ReadRawLittleEndian64());

         }

 

         /// <summary>

@@ -348,21 +346,6 @@ namespace Google.Protobuf
         }

 

         /// <summary>

-        /// Reads a group field value from the stream.

-        /// </summary>    

-        public void ReadGroup(int fieldNumber, IMessage message)

-        {

-            if (recursionDepth >= recursionLimit)

-            {

-                throw InvalidProtocolBufferException.RecursionLimitExceeded();

-            }

-            ++recursionDepth;

-            message.MergeFrom(this);

-            CheckLastTagWas(WireFormat.MakeTag(fieldNumber, WireFormat.WireType.EndGroup));

-            --recursionDepth;

-        }

-

-        /// <summary>

         /// Reads an embedded message field value from the stream.

         /// </summary>   

         public void ReadMessage(IMessage builder)

@@ -516,24 +499,34 @@ namespace Google.Protobuf
             return false;

         }

 

-        public void ReadStringArray(uint fieldTag, ICollection<string> list)

+        /// <summary>

+        /// Reads a string array.

+        /// </summary>

+        /// <remarks>The stream is assumed to be positioned after a tag indicating the field

+        /// repeated string value. A string is read, and then if the next tag is the same,

+        /// the process is repeated, until the next tag is a different one.</remarks>

+        /// <param name="list"></param>

+        public void ReadStringArray(ICollection<string> list)

         {

+            uint fieldTag = lastTag;

             do

             {

                 list.Add(ReadString());

             } while (ContinueArray(fieldTag));

         }

 

-        public void ReadBytesArray(uint fieldTag, ICollection<ByteString> list)

+        public void ReadBytesArray(ICollection<ByteString> list)

         {

+            uint fieldTag = lastTag;

             do

             {

                 list.Add(ReadBytes());

             } while (ContinueArray(fieldTag));

         }

 

-        public void ReadBoolArray(uint fieldTag, ICollection<bool> list)

+        public void ReadBoolArray(ICollection<bool> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -545,8 +538,9 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadInt32Array(uint fieldTag, ICollection<int> list)

+        public void ReadInt32Array(ICollection<int> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -558,8 +552,9 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadSInt32Array(uint fieldTag, ICollection<int> list)

+        public void ReadSInt32Array(ICollection<int> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -571,8 +566,9 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadUInt32Array(uint fieldTag, ICollection<uint> list)

+        public void ReadUInt32Array(ICollection<uint> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -584,8 +580,9 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadFixed32Array(uint fieldTag, ICollection<uint> list)

+        public void ReadFixed32Array(ICollection<uint> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -597,8 +594,9 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadSFixed32Array(uint fieldTag, ICollection<int> list)

+        public void ReadSFixed32Array(ICollection<int> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -610,8 +608,9 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadInt64Array(uint fieldTag, ICollection<long> list)

+        public void ReadInt64Array(ICollection<long> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -623,8 +622,9 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadSInt64Array(uint fieldTag, ICollection<long> list)

+        public void ReadSInt64Array(ICollection<long> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -636,8 +636,9 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadUInt64Array(uint fieldTag, ICollection<ulong> list)

+        public void ReadUInt64Array(ICollection<ulong> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -649,8 +650,9 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadFixed64Array(uint fieldTag, ICollection<ulong> list)

+        public void ReadFixed64Array(ICollection<ulong> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -662,8 +664,9 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadSFixed64Array(uint fieldTag, ICollection<long> list)

+        public void ReadSFixed64Array(ICollection<long> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -675,8 +678,9 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadDoubleArray(uint fieldTag, ICollection<double> list)

+        public void ReadDoubleArray(ICollection<double> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -688,8 +692,9 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadFloatArray(uint fieldTag, ICollection<float> list)

+        public void ReadFloatArray(ICollection<float> list)

         {

+            uint fieldTag = lastTag;

             bool isPacked;

             int holdLimit;

             if (BeginArray(fieldTag, out isPacked, out holdLimit))

@@ -701,9 +706,10 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadEnumArray<T>(uint fieldTag, RepeatedField<T> list)

+        public void ReadEnumArray<T>(RepeatedField<T> list)

             where T : struct, IComparable, IFormattable

         {

+            uint fieldTag = lastTag;

             WireFormat.WireType wformat = WireFormat.GetTagWireType(fieldTag);

 

             // 2.3 allows packed form even if the field is not declared packed.

@@ -727,9 +733,10 @@ namespace Google.Protobuf
             }

         }

 

-        public void ReadMessageArray<T>(uint fieldTag, ICollection<T> list, MessageParser<T> messageParser)

+        public void ReadMessageArray<T>(ICollection<T> list, MessageParser<T> messageParser)

             where T : IMessage<T>

         {

+            uint fieldTag = lastTag;

             do

             {

                 T message = messageParser.CreateTemplate();

@@ -737,17 +744,6 @@ namespace Google.Protobuf
                 list.Add(message);

             } while (ContinueArray(fieldTag));

         }

-

-        public void ReadGroupArray<T>(uint fieldTag, ICollection<T> list, MessageParser<T> messageParser)

-            where T : IMessage<T>

-        {

-            do

-            {

-                T message = messageParser.CreateTemplate();

-                ReadGroup(WireFormat.GetTagFieldNumber(fieldTag), message);

-                list.Add(message);

-            } while (ContinueArray(fieldTag));

-        }

         #endregion

 

         #region Underlying reading primitives

diff --git a/csharp/src/ProtocolBuffers/CodedOutputStream.cs b/csharp/src/ProtocolBuffers/CodedOutputStream.cs
index 1e6e7e55..e56ce789 100644
--- a/csharp/src/ProtocolBuffers/CodedOutputStream.cs
+++ b/csharp/src/ProtocolBuffers/CodedOutputStream.cs
@@ -35,12 +35,9 @@
 #endregion

 

 using System;

-using System.Collections;

 using System.IO;

-using System.Linq;

 using System.Text;

 using Google.Protobuf.Collections;

-using Google.Protobuf.Descriptors;

 

 namespace Google.Protobuf

 {

@@ -151,7 +148,7 @@ namespace Google.Protobuf
         /// </summary>

         public void WriteDouble(double value)

         {

-            WriteRawLittleEndian64((ulong)FrameworkPortability.DoubleToInt64(value));

+            WriteRawLittleEndian64((ulong)BitConverter.DoubleToInt64Bits(value));

         }

 

         /// <summary>

diff --git a/csharp/src/ProtocolBuffers/DescriptorProtos/DescriptorProtoFile.cs b/csharp/src/ProtocolBuffers/DescriptorProtos/DescriptorProtoFile.cs
index 67938260..7b7abd8e 100644
--- a/csharp/src/ProtocolBuffers/DescriptorProtos/DescriptorProtoFile.cs
+++ b/csharp/src/ProtocolBuffers/DescriptorProtos/DescriptorProtoFile.cs
@@ -358,7 +358,7 @@ namespace Google.Protobuf.DescriptorProtos {
             }
             break;
           case 10: {
-            input.ReadMessageArray(tag, file_, global::Google.Protobuf.DescriptorProtos.FileDescriptorProto.Parser);
+            input.ReadMessageArray(file_, global::Google.Protobuf.DescriptorProtos.FileDescriptorProto.Parser);
             break;
           }
         }
@@ -672,23 +672,23 @@ namespace Google.Protobuf.DescriptorProtos {
             break;
           }
           case 26: {
-            input.ReadStringArray(tag, dependency_);
+            input.ReadStringArray(dependency_);
             break;
           }
           case 34: {
-            input.ReadMessageArray(tag, messageType_, global::Google.Protobuf.DescriptorProtos.DescriptorProto.Parser);
+            input.ReadMessageArray(messageType_, global::Google.Protobuf.DescriptorProtos.DescriptorProto.Parser);
             break;
           }
           case 42: {
-            input.ReadMessageArray(tag, enumType_, global::Google.Protobuf.DescriptorProtos.EnumDescriptorProto.Parser);
+            input.ReadMessageArray(enumType_, global::Google.Protobuf.DescriptorProtos.EnumDescriptorProto.Parser);
             break;
           }
           case 50: {
-            input.ReadMessageArray(tag, service_, global::Google.Protobuf.DescriptorProtos.ServiceDescriptorProto.Parser);
+            input.ReadMessageArray(service_, global::Google.Protobuf.DescriptorProtos.ServiceDescriptorProto.Parser);
             break;
           }
           case 58: {
-            input.ReadMessageArray(tag, extension_, global::Google.Protobuf.DescriptorProtos.FieldDescriptorProto.Parser);
+            input.ReadMessageArray(extension_, global::Google.Protobuf.DescriptorProtos.FieldDescriptorProto.Parser);
             break;
           }
           case 66: {
@@ -707,12 +707,12 @@ namespace Google.Protobuf.DescriptorProtos {
           }
           case 82:
           case 80: {
-            input.ReadInt32Array(tag, publicDependency_);
+            input.ReadInt32Array(publicDependency_);
             break;
           }
           case 90:
           case 88: {
-            input.ReadInt32Array(tag, weakDependency_);
+            input.ReadInt32Array(weakDependency_);
             break;
           }
           case 98: {
@@ -979,23 +979,23 @@ namespace Google.Protobuf.DescriptorProtos {
             break;
           }
           case 18: {
-            input.ReadMessageArray(tag, field_, global::Google.Protobuf.DescriptorProtos.FieldDescriptorProto.Parser);
+            input.ReadMessageArray(field_, global::Google.Protobuf.DescriptorProtos.FieldDescriptorProto.Parser);
             break;
           }
           case 26: {
-            input.ReadMessageArray(tag, nestedType_, global::Google.Protobuf.DescriptorProtos.DescriptorProto.Parser);
+            input.ReadMessageArray(nestedType_, global::Google.Protobuf.DescriptorProtos.DescriptorProto.Parser);
             break;
           }
           case 34: {
-            input.ReadMessageArray(tag, enumType_, global::Google.Protobuf.DescriptorProtos.EnumDescriptorProto.Parser);
+            input.ReadMessageArray(enumType_, global::Google.Protobuf.DescriptorProtos.EnumDescriptorProto.Parser);
             break;
           }
           case 42: {
-            input.ReadMessageArray(tag, extensionRange_, global::Google.Protobuf.DescriptorProtos.DescriptorProto.Types.ExtensionRange.Parser);
+            input.ReadMessageArray(extensionRange_, global::Google.Protobuf.DescriptorProtos.DescriptorProto.Types.ExtensionRange.Parser);
             break;
           }
           case 50: {
-            input.ReadMessageArray(tag, extension_, global::Google.Protobuf.DescriptorProtos.FieldDescriptorProto.Parser);
+            input.ReadMessageArray(extension_, global::Google.Protobuf.DescriptorProtos.FieldDescriptorProto.Parser);
             break;
           }
           case 58: {
@@ -1006,15 +1006,15 @@ namespace Google.Protobuf.DescriptorProtos {
             break;
           }
           case 66: {
-            input.ReadMessageArray(tag, oneofDecl_, global::Google.Protobuf.DescriptorProtos.OneofDescriptorProto.Parser);
+            input.ReadMessageArray(oneofDecl_, global::Google.Protobuf.DescriptorProtos.OneofDescriptorProto.Parser);
             break;
           }
           case 74: {
-            input.ReadMessageArray(tag, reservedRange_, global::Google.Protobuf.DescriptorProtos.DescriptorProto.Types.ReservedRange.Parser);
+            input.ReadMessageArray(reservedRange_, global::Google.Protobuf.DescriptorProtos.DescriptorProto.Types.ReservedRange.Parser);
             break;
           }
           case 82: {
-            input.ReadStringArray(tag, reservedName_);
+            input.ReadStringArray(reservedName_);
             break;
           }
         }
@@ -1800,7 +1800,7 @@ namespace Google.Protobuf.DescriptorProtos {
             break;
           }
           case 18: {
-            input.ReadMessageArray(tag, value_, global::Google.Protobuf.DescriptorProtos.EnumValueDescriptorProto.Parser);
+            input.ReadMessageArray(value_, global::Google.Protobuf.DescriptorProtos.EnumValueDescriptorProto.Parser);
             break;
           }
           case 26: {
@@ -2086,7 +2086,7 @@ namespace Google.Protobuf.DescriptorProtos {
             break;
           }
           case 18: {
-            input.ReadMessageArray(tag, method_, global::Google.Protobuf.DescriptorProtos.MethodDescriptorProto.Parser);
+            input.ReadMessageArray(method_, global::Google.Protobuf.DescriptorProtos.MethodDescriptorProto.Parser);
             break;
           }
           case 26: {
@@ -2735,7 +2735,7 @@ namespace Google.Protobuf.DescriptorProtos {
             break;
           }
           case 7994: {
-            input.ReadMessageArray(tag, uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
+            input.ReadMessageArray(uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
             break;
           }
         }
@@ -2933,7 +2933,7 @@ namespace Google.Protobuf.DescriptorProtos {
             break;
           }
           case 7994: {
-            input.ReadMessageArray(tag, uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
+            input.ReadMessageArray(uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
             break;
           }
         }
@@ -3167,7 +3167,7 @@ namespace Google.Protobuf.DescriptorProtos {
             break;
           }
           case 7994: {
-            input.ReadMessageArray(tag, uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
+            input.ReadMessageArray(uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
             break;
           }
         }
@@ -3323,7 +3323,7 @@ namespace Google.Protobuf.DescriptorProtos {
             break;
           }
           case 7994: {
-            input.ReadMessageArray(tag, uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
+            input.ReadMessageArray(uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
             break;
           }
         }
@@ -3437,7 +3437,7 @@ namespace Google.Protobuf.DescriptorProtos {
             break;
           }
           case 7994: {
-            input.ReadMessageArray(tag, uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
+            input.ReadMessageArray(uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
             break;
           }
         }
@@ -3551,7 +3551,7 @@ namespace Google.Protobuf.DescriptorProtos {
             break;
           }
           case 7994: {
-            input.ReadMessageArray(tag, uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
+            input.ReadMessageArray(uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
             break;
           }
         }
@@ -3665,7 +3665,7 @@ namespace Google.Protobuf.DescriptorProtos {
             break;
           }
           case 7994: {
-            input.ReadMessageArray(tag, uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
+            input.ReadMessageArray(uninterpretedOption_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Parser);
             break;
           }
         }
@@ -3875,7 +3875,7 @@ namespace Google.Protobuf.DescriptorProtos {
             }
             break;
           case 18: {
-            input.ReadMessageArray(tag, name_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Types.NamePart.Parser);
+            input.ReadMessageArray(name_, global::Google.Protobuf.DescriptorProtos.UninterpretedOption.Types.NamePart.Parser);
             break;
           }
           case 26: {
@@ -4111,7 +4111,7 @@ namespace Google.Protobuf.DescriptorProtos {
             }
             break;
           case 10: {
-            input.ReadMessageArray(tag, location_, global::Google.Protobuf.DescriptorProtos.SourceCodeInfo.Types.Location.Parser);
+            input.ReadMessageArray(location_, global::Google.Protobuf.DescriptorProtos.SourceCodeInfo.Types.Location.Parser);
             break;
           }
         }
@@ -4287,12 +4287,12 @@ namespace Google.Protobuf.DescriptorProtos {
                 break;
               case 10:
               case 8: {
-                input.ReadInt32Array(tag, path_);
+                input.ReadInt32Array(path_);
                 break;
               }
               case 18:
               case 16: {
-                input.ReadInt32Array(tag, span_);
+                input.ReadInt32Array(span_);
                 break;
               }
               case 26: {
@@ -4304,7 +4304,7 @@ namespace Google.Protobuf.DescriptorProtos {
                 break;
               }
               case 50: {
-                input.ReadStringArray(tag, leadingDetachedComments_);
+                input.ReadStringArray(leadingDetachedComments_);
                 break;
               }
             }
diff --git a/csharp/src/ProtocolBuffers/FrameworkPortability.cs b/csharp/src/ProtocolBuffers/FrameworkPortability.cs
index 5fa7c4e7..06246a9e 100644
--- a/csharp/src/ProtocolBuffers/FrameworkPortability.cs
+++ b/csharp/src/ProtocolBuffers/FrameworkPortability.cs
@@ -35,8 +35,6 @@
 #endregion

 

 using System;

-using System.Globalization;

-using System.Reflection;

 using System.Text.RegularExpressions;

 

 namespace Google.Protobuf

@@ -46,66 +44,10 @@ namespace Google.Protobuf
     /// </summary>

     internal static class FrameworkPortability

     {

-#if COMPACT_FRAMEWORK

-        internal const string NewLine = "\n";

-#else

-        internal static readonly string NewLine = System.Environment.NewLine;

-#endif

-

-#if CLIENTPROFILE

-        internal const RegexOptions CompiledRegexWhereAvailable = RegexOptions.Compiled;

-#else

-        internal const RegexOptions CompiledRegexWhereAvailable = RegexOptions.None;

-#endif

-

-        internal static CultureInfo InvariantCulture 

-        { 

-            get { return CultureInfo.InvariantCulture; } 

-        }

-

-        internal static double Int64ToDouble(long value)

-        {

-#if CLIENTPROFILE

-            return BitConverter.Int64BitsToDouble(value);

-#else

-            double[] arresult = new double[1];

-            Buffer.BlockCopy(new[] { value }, 0, arresult, 0, 8);

-            return arresult[0];

-#endif

-        }

-

-        internal static long DoubleToInt64(double value)

-        {

-#if CLIENTPROFILE

-            return BitConverter.DoubleToInt64Bits(value);

-#else

-            long[] arresult = new long[1];

-            Buffer.BlockCopy(new[] { value }, 0, arresult, 0, 8);

-            return arresult[0];

-#endif

-        }

-

-        internal static bool TryParseInt32(string text, out int number)

-        {

-            return TryParseInt32(text, NumberStyles.Any, InvariantCulture, out number);

-        }

-

-        internal static bool TryParseInt32(string text, NumberStyles style, IFormatProvider format, out int number)

-        {

-#if COMPACT_FRAMEWORK

-                try 

-                {

-                    number = int.Parse(text, style, format); 

-                    return true;

-                }

-                catch 

-                {

-                    number = 0;

-                    return false; 

-                }

-#else

-            return int.TryParse(text, style, format, out number);

-#endif

-        }

+        // The value of RegexOptions.Compiled is 8. We can test for the presence at

+        // execution time using Enum.IsDefined, so a single build will do the right thing

+        // on each platform.

+        internal static readonly RegexOptions CompiledRegexWhereAvailable =

+            Enum.IsDefined(typeof(RegexOptions), 8) ? (RegexOptions)8 : RegexOptions.None;

     }

 }
\ No newline at end of file
diff --git a/csharp/src/ProtocolBuffers/IMessage.cs b/csharp/src/ProtocolBuffers/IMessage.cs
index 55b6fc5d..9c2a2d85 100644
--- a/csharp/src/ProtocolBuffers/IMessage.cs
+++ b/csharp/src/ProtocolBuffers/IMessage.cs
@@ -34,30 +34,63 @@
 

 #endregion

 

-using System;

-using System.Collections.Generic;

-using System.IO;

-using Google.Protobuf.Descriptors;

 using Google.Protobuf.FieldAccess;

 

 namespace Google.Protobuf

 {

 

-    // TODO(jonskeet): Do we want a "weak" version of IReflectedMessage?

+    // TODO(jonskeet): Do we want a "weak" (non-generic) version of IReflectedMessage?

+

+    /// <summary>

+    /// Reflection support for a specific message type. message

+    /// </summary>

+    /// <typeparam name="T">The message type being reflected.</typeparam>

     public interface IReflectedMessage<T> where T : IMessage<T>

     {

         FieldAccessorTable<T> Fields { get; }

+        // TODO(jonskeet): Descriptor? Or a single property which has "all you need for reflection"?

     }

 

+    /// <summary>

+    /// Interface for a Protocol Buffers message, supporting

+    /// basic operations required for serialization.

+    /// </summary>

     public interface IMessage

     {

+        /// <summary>

+        /// Merges the data from the specified coded input stream with the current message.

+        /// </summary>

+        /// <remarks>See the user guide for precise merge semantics.</remarks>

+        /// <param name="input"></param>

         void MergeFrom(CodedInputStream input);

+

+        /// <summary>

+        /// Writes the data to the given coded output stream.

+        /// </summary>

+        /// <param name="output">Coded output stream to write the data to. Must not be null.</param>

         void WriteTo(CodedOutputStream output);

+

+        /// <summary>

+        /// Calculates the size of this message in Protocol Buffer wire format, in bytes.

+        /// </summary>

+        /// <returns>The number of bytes required to write this message

+        /// to a coded output stream.</returns>

         int CalculateSize();

     }

 

+    /// <summary>

+    /// Generic interface for a Protocol Buffers message,

+    /// where the type parameter is expected to be the same type as

+    /// the implementation class.

+    /// </summary>

+    /// <typeparam name="T">The message type.</typeparam>

     public interface IMessage<T> : IMessage where T : IMessage<T>

     {

+        /// <summary>

+        /// Merges the given message into this one.

+        /// </summary>

+        /// <remarks>See the user guide for precise merge semantics.</remarks>

+        /// <param name="message">The message to merge with this one. Must not be null.</param>

         void MergeFrom(T message);

     }

 }
\ No newline at end of file
diff --git a/csharp/src/ProtocolBuffers/Extensions.cs b/csharp/src/ProtocolBuffers/MessageExtensions.cs
index 7f23057e..57cecfd4 100644
--- a/csharp/src/ProtocolBuffers/Extensions.cs
+++ b/csharp/src/ProtocolBuffers/MessageExtensions.cs
@@ -2,11 +2,15 @@
 
 namespace Google.Protobuf
 {
-    // TODO: MessageExtensions?
-    public static class Extensions
+    /// <summary>
+    /// Extension methods on <see cref="IMessage"/> and <see cref="IMessage{T}"/>.
+    /// </summary>
+    public static class MessageExtensions
     {
         public static void MergeFrom(this IMessage message, byte[] data)
         {
+            ThrowHelper.ThrowIfNull(message, "message");
+            ThrowHelper.ThrowIfNull(data, "data");
             CodedInputStream input = CodedInputStream.CreateInstance(data);
             message.MergeFrom(input);
             input.CheckLastTagWas(0);
@@ -14,6 +18,8 @@ namespace Google.Protobuf
 
         public static void MergeFrom(this IMessage message, ByteString data)
         {
+            ThrowHelper.ThrowIfNull(message, "message");
+            ThrowHelper.ThrowIfNull(data, "data");
             CodedInputStream input = data.CreateCodedInput();
             message.MergeFrom(input);
             input.CheckLastTagWas(0);
@@ -21,6 +27,8 @@ namespace Google.Protobuf
 
         public static void MergeFrom(this IMessage message, Stream input)
         {
+            ThrowHelper.ThrowIfNull(message, "message");
+            ThrowHelper.ThrowIfNull(input, "input");
             CodedInputStream codedInput = CodedInputStream.CreateInstance(input);
             message.MergeFrom(codedInput);
             codedInput.CheckLastTagWas(0);
@@ -28,6 +36,8 @@ namespace Google.Protobuf
 
         public static void MergeDelimitedFrom(this IMessage message, Stream input)
         {
+            ThrowHelper.ThrowIfNull(message, "message");
+            ThrowHelper.ThrowIfNull(input, "input");
             int size = (int)CodedInputStream.ReadRawVarint32(input);
             Stream limitedStream = new LimitedInputStream(input, size);
             message.MergeFrom(limitedStream);
@@ -35,6 +45,7 @@ namespace Google.Protobuf
 
         public static byte[] ToByteArray(this IMessage message)
         {
+            ThrowHelper.ThrowIfNull(message, "message");
             byte[] result = new byte[message.CalculateSize()];
             CodedOutputStream output = CodedOutputStream.CreateInstance(result);
             message.WriteTo(output);
@@ -44,18 +55,17 @@ namespace Google.Protobuf
 
         public static void WriteTo(this IMessage message, Stream output)
         {
+            ThrowHelper.ThrowIfNull(message, "message");
+            ThrowHelper.ThrowIfNull(output, "output");
             CodedOutputStream codedOutput = CodedOutputStream.CreateInstance(output);
             message.WriteTo(codedOutput);
             codedOutput.Flush();
         }
 
-        public static void WriteTo(this IMessage message, CodedOutputStream output)
-        {
-            message.WriteTo(output);
-        }
-
         public static void WriteDelimitedTo(this IMessage message, Stream output)
         {
+            ThrowHelper.ThrowIfNull(message, "message");
+            ThrowHelper.ThrowIfNull(output, "output");
             CodedOutputStream codedOutput = CodedOutputStream.CreateInstance(output);
             codedOutput.WriteRawVarint32((uint)message.CalculateSize());
             message.WriteTo(codedOutput);
@@ -64,6 +74,7 @@ namespace Google.Protobuf
 
         public static ByteString ToByteString(this IMessage message)
         {
+            ThrowHelper.ThrowIfNull(message, "message");
             return ByteString.AttachBytes(message.ToByteArray());
         }        
     }
diff --git a/csharp/src/ProtocolBuffers/MessageParser.cs b/csharp/src/ProtocolBuffers/MessageParser.cs
index 722435cc..18cda2dc 100644
--- a/csharp/src/ProtocolBuffers/MessageParser.cs
+++ b/csharp/src/ProtocolBuffers/MessageParser.cs
@@ -1,26 +1,58 @@
 using System;
 using System.IO;
-using Google.Protobuf;
 
 namespace Google.Protobuf
 {
+    /// <summary>
+    /// A parser for a specific message type.
+    /// </summary>
+    /// <remarks>
+    /// <p>
+    /// This delegates most behavior to the
+    /// <see cref="IMessage.MergeFrom"/> implementation within the original type, but
+    /// provides convenient overloads to parse from a variety of sources.
+    /// </p>
+    /// <p>
+    /// Most applications will never need to create their own instances of this type;
+    /// instead, use the static <c>Parser</c> property of a generated message type to obtain a
+    /// parser for that type.
+    /// </p>
+    /// </remarks>
+    /// <typeparam name="T">The type of message to be parsed.</typeparam>
     public sealed class MessageParser<T> where T : IMessage<T>
     {
         private readonly Func<T> factory; 
 
+        /// <summary>
+        /// Creates a new parser.
+        /// </summary>
+        /// <remarks>
+        /// The factory method is effectively an optimization over using a generic constraint
+        /// to require a parameterless constructor: delegates are significantly faster to execute.
+        /// </remarks>
+        /// <param name="factory">Function to invoke when a new, empty message is required.</param>
         public MessageParser(Func<T> factory)
         {
             this.factory = factory;
         }
 
-        // Creates a template instance ready for population.
+        /// <summary>
+        /// Creates a template instance ready for population.
+        /// </summary>
+        /// <returns>An empty message.</returns>
         internal T CreateTemplate()
         {
             return factory();
         }
 
+        /// <summary>
+        /// Parses a message from a byte array.
+        /// </summary>
+        /// <param name="data">The byte array containing the message. Must not be null.</param>
+        /// <returns>The newly parsed message.</returns>
         public T ParseFrom(byte[] data)
         {
+            ThrowHelper.ThrowIfNull(data, "data");
             T message = factory();
             message.MergeFrom(data);
             return message;
@@ -28,6 +60,7 @@ namespace Google.Protobuf
 
         public T ParseFrom(ByteString data)
         {
+            ThrowHelper.ThrowIfNull(data, "data");
             T message = factory();
             message.MergeFrom(data);
             return message;
diff --git a/csharp/src/ProtocolBuffers/ProtocolBuffers.csproj b/csharp/src/ProtocolBuffers/ProtocolBuffers.csproj
index 3a07e87f..33a32ff2 100644
--- a/csharp/src/ProtocolBuffers/ProtocolBuffers.csproj
+++ b/csharp/src/ProtocolBuffers/ProtocolBuffers.csproj
@@ -84,7 +84,8 @@
     <Compile Include="Descriptors\MethodDescriptor.cs" />

     <Compile Include="Descriptors\PackageDescriptor.cs" />

     <Compile Include="Descriptors\ServiceDescriptor.cs" />

-    <Compile Include="Extensions.cs" />

+    <Compile Include="FrameworkPortability.cs" />

+    <Compile Include="MessageExtensions.cs" />

     <Compile Include="FieldAccess\FieldAccessorBase.cs" />

     <Compile Include="FieldAccess\ReflectionUtil.cs" />

     <Compile Include="FieldAccess\RepeatedFieldAccessor.cs" />

@@ -92,7 +93,6 @@
     <Compile Include="FieldAccess\IFieldAccessor.cs" />

     <Compile Include="FieldAccess\FieldAccessorTable.cs" />

     <Compile Include="FieldAccess\OneofAccessor.cs" />

-    <Compile Include="FrameworkPortability.cs" />

     <Compile Include="IMessage.cs" />

     <Compile Include="InvalidProtocolBufferException.cs" />

     <Compile Include="LimitedInputStream.cs" />

diff --git a/csharp/src/ProtocolBuffers/ThrowHelper.cs b/csharp/src/ProtocolBuffers/ThrowHelper.cs
index 097b5032..c12a48a3 100644
--- a/csharp/src/ProtocolBuffers/ThrowHelper.cs
+++ b/csharp/src/ProtocolBuffers/ThrowHelper.cs
@@ -42,12 +42,12 @@ namespace Google.Protobuf
     /// <summary>

     /// Helper methods for throwing exceptions

     /// </summary>

-    public static class ThrowHelper

+    internal static class ThrowHelper

     {

         /// <summary>

         /// Throws an ArgumentNullException if the given value is null.

         /// </summary>

-        public static void ThrowIfNull(object value, string name)

+        internal static void ThrowIfNull(object value, string name)

         {

             if (value == null)

             {

@@ -58,7 +58,7 @@ namespace Google.Protobuf
         /// <summary>

         /// Throws an ArgumentNullException if the given value is null.

         /// </summary>

-        public static void ThrowIfNull(object value)

+        internal static void ThrowIfNull(object value)

         {

             if (value == null)

             {

@@ -69,7 +69,7 @@ namespace Google.Protobuf
         /// <summary>

         /// Throws an ArgumentNullException if the given value or any element within it is null.

         /// </summary>

-        public static void ThrowIfAnyNull<T>(IEnumerable<T> sequence)

+        internal static void ThrowIfAnyNull<T>(IEnumerable<T> sequence)

         {

             foreach (T t in sequence)

             {

@@ -79,14 +79,5 @@ namespace Google.Protobuf
                 }

             }

         }

-

-        public static Exception CreateMissingMethod(Type type, string methodName)

-        {

-#if CLIENTPROFILE

-            return new System.MissingMethodException(type.FullName, methodName);

-#else

-            return new System.ArgumentException(String.Format("The method '{0}' was not found on type {1}.", methodName, type));

-#endif

-        }

     }

 }
\ No newline at end of file
diff --git a/src/google/protobuf/compiler/csharp/csharp_repeated_enum_field.cc b/src/google/protobuf/compiler/csharp/csharp_repeated_enum_field.cc
index c78aaef6..29c931e3 100644
--- a/src/google/protobuf/compiler/csharp/csharp_repeated_enum_field.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_repeated_enum_field.cc
@@ -76,7 +76,7 @@ void RepeatedEnumFieldGenerator::GenerateMergingCode(io::Printer* printer) {
 void RepeatedEnumFieldGenerator::GenerateParsingCode(io::Printer* printer) {
   printer->Print(
     variables_,
-    "input.ReadEnumArray<$type_name$>(tag, $name$_);\n");
+    "input.ReadEnumArray<$type_name$>($name$_);\n");
 }
 
 void RepeatedEnumFieldGenerator::GenerateSerializationCode(io::Printer* printer) {
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 3553fe12..3ab0b190 100644
--- a/src/google/protobuf/compiler/csharp/csharp_repeated_message_field.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_repeated_message_field.cc
@@ -75,7 +75,7 @@ void RepeatedMessageFieldGenerator::GenerateMergingCode(io::Printer* printer) {
 void RepeatedMessageFieldGenerator::GenerateParsingCode(io::Printer* printer) {
   printer->Print(
     variables_,
-    "input.ReadMessageArray(tag, $name$_, $type_name$.Parser);\n");
+    "input.ReadMessageArray($name$_, $type_name$.Parser);\n");
 }
 
 void RepeatedMessageFieldGenerator::GenerateSerializationCode(io::Printer* printer) {
diff --git a/src/google/protobuf/compiler/csharp/csharp_repeated_primitive_field.cc b/src/google/protobuf/compiler/csharp/csharp_repeated_primitive_field.cc
index fe8a4364..cc787d50 100644
--- a/src/google/protobuf/compiler/csharp/csharp_repeated_primitive_field.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_repeated_primitive_field.cc
@@ -75,7 +75,7 @@ void RepeatedPrimitiveFieldGenerator::GenerateMergingCode(io::Printer* printer)
 
 void RepeatedPrimitiveFieldGenerator::GenerateParsingCode(io::Printer* printer) {
   printer->Print(variables_,
-    "input.Read$capitalized_type_name$Array(tag, $name$_);\n");
+    "input.Read$capitalized_type_name$Array($name$_);\n");
 }
 
 void RepeatedPrimitiveFieldGenerator::GenerateSerializationCode(