Fix handling of repeated wrappers

Previously we were incorrectly packing wrapper types.
This also refactors FieldCodec a bit as well, using more C# 6-ness.

1 files changed, 4 insertions, 5 deletions

diff --git a/csharp/src/Google.Protobuf/Collections/RepeatedField.cs b/csharp/src/Google.Protobuf/Collections/RepeatedField.cs
index e3f65afe..1cde03bc 100644
--- a/csharp/src/Google.Protobuf/Collections/RepeatedField.cs
+++ b/csharp/src/Google.Protobuf/Collections/RepeatedField.cs
@@ -34,7 +34,6 @@ using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Text;
-using Google.Protobuf.Compatibility;
 
 namespace Google.Protobuf.Collections
 {
@@ -96,8 +95,8 @@ namespace Google.Protobuf.Collections
             // iteration.
             uint tag = input.LastTag;
             var reader = codec.ValueReader;
-            // Value types can be packed or not.
-            if (typeof(T).IsValueType() && WireFormat.GetTagWireType(tag) == WireFormat.WireType.LengthDelimited)
+            // Non-nullable value types can be packed or not.
+            if (FieldCodec<T>.IsPackedRepeatedField(tag))
             {
                 int length = input.ReadLength();
                 if (length > 0)
@@ -134,7 +133,7 @@ namespace Google.Protobuf.Collections
                 return 0;
             }
             uint tag = codec.Tag;
-            if (typeof(T).IsValueType() && WireFormat.GetTagWireType(tag) == WireFormat.WireType.LengthDelimited)
+            if (codec.PackedRepeatedField)
             {
                 int dataSize = CalculatePackedDataSize(codec);
                 return CodedOutputStream.ComputeRawVarint32Size(tag) +
@@ -186,7 +185,7 @@ namespace Google.Protobuf.Collections
             }
             var writer = codec.ValueWriter;
             var tag = codec.Tag;
-            if (typeof(T).IsValueType() && WireFormat.GetTagWireType(tag) == WireFormat.WireType.LengthDelimited)
+            if (codec.PackedRepeatedField)
             {
                 // Packed primitive type
                 uint size = (uint)CalculatePackedDataSize(codec);