Added unit test for CSHARP-100. Not able to reproduce yet.

Bson/DefaultSerializer/Attributes/BsonKnownTypesAttribute.cs

@@ -19,7 +19,7 @@ using System.Linq;
 using System.Text;
 
 namespace MongoDB.Bson.DefaultSerializer {
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = true)]
+    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, AllowMultiple = true)]
     public class BsonKnownTypesAttribute : Attribute {
         #region private fields
         private Type[] knownTypes;

DriverOnlineTests/DriverOnlineTests.csproj

@@ -60,6 +60,7 @@
     <Reference Include="System.Core">
       <RequiredTargetFramework>3.5</RequiredTargetFramework>
     </Reference>
+    <Reference Include="System.Runtime.Serialization" />
     <Reference Include="System.Xml.Linq">
       <RequiredTargetFramework>3.5</RequiredTargetFramework>
     </Reference>
@@ -77,6 +78,7 @@
     <Compile Include="Jira\CSharp92Tests.cs" />
     <Compile Include="Jira\CSharp93Tests.cs" />
     <Compile Include="Jira\CSharp98Tests.cs" />
+    <Compile Include="Jira\CSharp100Tests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Samples\MagicDiscriminatorTests.cs" />
   </ItemGroup>

DriverOnlineTests/Jira/CSharp100Tests.cs

@@ -0,0 +1,66 @@
+/* Copyright 2010 10gen Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Runtime.Serialization;
+using System.Text;
+using NUnit.Framework;
+
+using MongoDB.Bson;
+using MongoDB.Bson.DefaultSerializer;
+using MongoDB.Driver;
+using MongoDB.Driver.Builders;
+
+namespace MongoDB.DriverOnlineTests.Jira.CSharpxx {
+    [TestFixture]
+    public class CSharp100Tests {
+        [DataContract]
+        private class ParentClass {
+            [BsonId]
+            public ObjectId Id { get; set; }
+        }
+
+        [DataContract]
+        private class ChildClass : ParentClass {
+            [DataMember(Order = 1)]
+            [BsonIgnoreIfNull]
+            public IList<SomeClass> SomeProperty { get; set; }
+        }
+
+        [DataContract]
+        public class SomeClass {
+        }
+
+        [Test]
+        public void TestDeserializationOfTwoBs() {
+            var server = MongoServer.Create("mongodb://localhost/?safe=true");
+            var database = server["onlinetests"];
+            var collection = database["csharpxx"];
+
+            collection.RemoveAll();
+            var obj = new ChildClass { SomeProperty = null };
+            collection.Save(obj, SafeMode.True);
+            obj = new ChildClass { SomeProperty = new List<SomeClass>() };
+            collection.Save(obj, SafeMode.True);
+            obj = new ChildClass { SomeProperty = new List<SomeClass> { new SomeClass() } };
+            collection.Save(obj, SafeMode.True);
+            obj = new ChildClass { SomeProperty = new List<SomeClass> { new SomeClass(), new SomeClass() } };
+            collection.Save(obj, SafeMode.True);
+        }
+    }
+}