Merge fix for NH-3641 (pull request #283).

Author: oskarb

src/NHibernate.Test/NHSpecificTest/NH3641/Domain.cs

@@ -0,0 +1,19 @@
+
+namespace NHibernate.Test.NHSpecificTest.NH3641
+{
+	public interface IEntity
+	{
+		int Id { get; set; }
+		bool Flag { get; set; }
+		Entity ChildConcrete { get; set; }
+		IEntity ChildInterface { get; set; }
+	}
+
+	public class Entity : IEntity
+	{
+		public virtual int Id { get; set; }
+		public virtual bool Flag { get; set; }
+		public virtual Entity ChildConcrete { get; set; }
+		public virtual IEntity ChildInterface { get; set; }
+	}
+}

src/NHibernate.Test/NHSpecificTest/NH3641/Mappings.hbm.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
+                   assembly="NHibernate.Test"
+                   namespace="NHibernate.Test.NHSpecificTest.NH3641">
+
+    <class name="Entity" table="Entity" lazy="true">
+        <id name="Id" access="property" column="Id" type="Int32" unsaved-value="0">
+            <generator class="assigned" />
+        </id>
+
+        <property name="Flag" type="Boolean">
+            <column name="Flag" not-null="true" />
+        </property>
+
+        <many-to-one name="ChildConcrete" access="property"  class="Entity" column="ChildConcreteId" lazy="proxy" />
+        <many-to-one name="ChildInterface" access="property" class="Entity" column="ChildInterfaceId" lazy="proxy" />
+    </class>
+
+</hibernate-mapping>

src/NHibernate.Test/NHSpecificTest/NH3641/TestFixture.cs

@@ -0,0 +1,63 @@
+using System.Linq;
+using NHibernate.Linq;
+using NUnit.Framework;
+
+namespace NHibernate.Test.NHSpecificTest.NH3641
+{
+	public class TestFixture : BugTestCase
+	{
+		protected override void OnSetUp()
+		{
+			using (var session = OpenSession())
+			using (var tx = session.BeginTransaction())
+			{
+				var child = new Entity {Id = 1, Flag = true};
+				var parent = new Entity {Id = 2, ChildInterface = child, ChildConcrete = child};
+
+				session.Save(child);
+				session.Save(parent);
+
+				tx.Commit();
+			}
+		}
+
+		protected override void OnTearDown()
+		{
+			using (var session = OpenSession())
+			using (var tx = session.BeginTransaction())
+			{
+				DeleteAll<Entity>(session);
+				tx.Commit();
+			}
+		}
+
+		private static void DeleteAll<T>(ISession session)
+		{
+			session.CreateQuery("delete from " + typeof (T).Name).ExecuteUpdate();
+		}
+
+		[Test]
+		public void TrueOrChildPropertyConcrete()
+		{
+			using (var session = OpenSession())
+			{
+				var result = session.Query<IEntity>()
+					.Where(x => x.ChildConcrete == null || x.ChildConcrete.Flag)
+					.ToList();
+				Assert.That(result, Has.Count.EqualTo(2));
+			}
+		}
+
+		[Test]
+		public void TrueOrChildPropertyInterface()
+		{
+			using (var session = OpenSession())
+			{
+				var result = session.Query<IEntity>()
+					.Where(x => x.ChildInterface == null || ((Entity) x.ChildInterface).Flag)
+					.ToList();
+				Assert.That(result, Has.Count.EqualTo(2));
+			}
+		}
+	}
+}

src/NHibernate.Test/NHibernate.Test.csproj

@@ -1059,6 +1059,8 @@
     <Compile Include="NHSpecificTest\NH3145\Model.cs" />
     <Compile Include="NHSpecificTest\NH2860\ClassA.cs" />
     <Compile Include="NHSpecificTest\NH2860\SampleTest.cs" />
+    <Compile Include="NHSpecificTest\NH3641\Domain.cs" />
+    <Compile Include="NHSpecificTest\NH3641\TestFixture.cs" />
     <Compile Include="NHSpecificTest\Properties\CompositePropertyRefTest.cs" />
     <Compile Include="NHSpecificTest\Properties\DynamicEntityTest.cs" />
     <Compile Include="NHSpecificTest\Properties\Model.cs" />
@@ -2913,6 +2915,7 @@
     <EmbeddedResource Include="NHSpecificTest\NH3614\Mappings.hbm.xml" />
     <EmbeddedResource Include="NHSpecificTest\NH3505\Mappings.hbm.xml" />
     <EmbeddedResource Include="NHSpecificTest\NH3428\Mappings.hbm.xml" />
+    <EmbeddedResource Include="NHSpecificTest\NH3641\Mappings.hbm.xml" />
     <EmbeddedResource Include="NHSpecificTest\NH3408\Mappings.hbm.xml" />
     <EmbeddedResource Include="NHSpecificTest\NH2408\Mappings.hbm.xml" />
     <EmbeddedResource Include="NHSpecificTest\NH2297\MappingsNames.hbm.xml" />

src/NHibernate/Linq/ReWriters/AddJoinsReWriter.cs

@@ -1,3 +1,5 @@
+using System.Linq;
+using NHibernate.Engine;
 using NHibernate.Linq.Visitors;
 using Remotion.Linq;
 using Remotion.Linq.Clauses;
@@ -12,12 +14,12 @@ internal interface IIsEntityDecider
 
 	public class AddJoinsReWriter : QueryModelVisitorBase, IIsEntityDecider
 	{
-		private readonly ISessionFactory _sessionFactory;
+		private readonly ISessionFactoryImplementor _sessionFactory;
 		private readonly SelectJoinDetector _selectJoinDetector;
 		private readonly ResultOperatorAndOrderByJoinDetector _resultOperatorAndOrderByJoinDetector;
 		private readonly WhereJoinDetector _whereJoinDetector;
 
-		private AddJoinsReWriter(ISessionFactory sessionFactory, QueryModel queryModel)
+		private AddJoinsReWriter(ISessionFactoryImplementor sessionFactory, QueryModel queryModel)
 		{
 			_sessionFactory = sessionFactory;
 			var joiner = new Joiner(queryModel);
@@ -26,7 +28,7 @@ private AddJoinsReWriter(ISessionFactory sessionFactory, QueryModel queryModel)
 			_whereJoinDetector = new WhereJoinDetector(this, joiner);
 		}
 
-		public static void ReWrite(QueryModel queryModel, ISessionFactory sessionFactory)
+		public static void ReWrite(QueryModel queryModel, ISessionFactoryImplementor sessionFactory)
 		{
 			new AddJoinsReWriter(sessionFactory, queryModel).VisitQueryModel(queryModel);
 		}
@@ -53,7 +55,7 @@ public override void VisitWhereClause(WhereClause whereClause, QueryModel queryM
 
 		public bool IsEntity(System.Type type)
 		{
-			return _sessionFactory.GetClassMetadata(type) != null;
+			return _sessionFactory.GetImplementors(type.FullName).Any();
 		}
 
 		public bool IsIdentifier(System.Type type, string propertyName)