Test for problem with backreference with the same key name

Src/NHibernate.Envers.Tests/NHibernate.Envers.Tests.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFrameworks>netCoreApp2.0;net461</TargetFrameworks>

Src/NHibernate.Envers.Tests/NetSpecific/Integration/ManyToMany/BackReference/BackReferenceEntity.cs

@@ -0,0 +1,24 @@
+using NHibernate.Envers.Configuration.Attributes;
+
+namespace NHibernate.Envers.Tests.NetSpecific.Integration.ManyToMany.BackReference
+{
+	[Audited]
+	public class BackReferenceEntity
+	{
+		public virtual long Id { get; set; }
+
+		public virtual OwningEntity Owning { get; set; }
+
+		public override bool Equals(object obj)
+		{
+			if (!(obj is BackReferenceEntity other))
+				return false;
+			return Id == other.Id;
+		}
+
+		public override int GetHashCode()
+		{
+			return Id.GetHashCode();
+		}
+	}
+}

Src/NHibernate.Envers.Tests/NetSpecific/Integration/ManyToMany/BackReference/BackReferenceTest.cs

@@ -0,0 +1,38 @@
+using System.Collections.Generic;
+using NUnit.Framework;
+
+namespace NHibernate.Envers.Tests.NetSpecific.Integration.ManyToMany.BackReference
+{
+	public class BackReferenceTest : TestBase
+	{
+		public BackReferenceTest(AuditStrategyForTest strategyType) : base(strategyType)
+		{
+		}
+
+		protected override IEnumerable<string> Mappings => new[] {"NetSpecific.Integration.ManyToMany.BackReference.Mapping.hbm.xml"};
+
+		protected override void Initialize()
+		{
+		}
+
+		[Test]
+		public void VerifySave()
+		{
+			using (var tx = Session.BeginTransaction())
+			{
+				var item = new BackReferenceEntity();
+
+				Session.Save(item);
+
+				var entity = new OwningEntity
+				{
+					Items = { item }
+				};
+
+				Session.Save(entity);
+
+				tx.Commit();
+			}
+		}
+	}
+}

Src/NHibernate.Envers.Tests/NetSpecific/Integration/ManyToMany/BackReference/Mapping.hbm.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
+                   assembly="NHibernate.Envers.Tests"
+                   namespace="NHibernate.Envers.Tests.NetSpecific.Integration.ManyToMany.BackReference">
+    <class name="OwningEntity">
+        <id name="Id" column="owning_id">
+            <generator class="native"/>
+        </id>
+        <bag name="Items" table="owning_item">
+            <key column="owning_id" />
+            <many-to-many class="BackReferenceEntity" column="item_id" />
+        </bag>
+    </class>
+    <class name="BackReferenceEntity">
+        <id name="Id" column="item_id">
+            <generator class="native"/>
+        </id>
+        <many-to-one name="Owning" class="OwningEntity" column="owning_id"/>
+    </class>
+</hibernate-mapping>

Src/NHibernate.Envers.Tests/NetSpecific/Integration/ManyToMany/BackReference/OwningEntity.cs

@@ -0,0 +1,25 @@
+using System.Collections.Generic;
+using NHibernate.Envers.Configuration.Attributes;
+
+namespace NHibernate.Envers.Tests.NetSpecific.Integration.ManyToMany.BackReference
+{
+	[Audited]
+	public class OwningEntity
+	{
+		public virtual long Id { get; set; }
+
+		public virtual IList<BackReferenceEntity> Items { get; protected set; } = new List<BackReferenceEntity>();
+
+		public override bool Equals(object obj)
+		{
+			if (!(obj is OwningEntity other))
+				return false;
+			return Id == other.Id;
+		}
+
+		public override int GetHashCode()
+		{
+			return Id.GetHashCode();
+		}
+	}
+}