Inserting multiple associations of the same entity fails

src/NHibernate.Test/Async/BulkManipulation/HQLBulkOperations.cs

@@ -43,5 +43,21 @@ public async Task SimpleDeleteAsync()
 				await (tx.CommitAsync());
 			}
 		}
+
+		[Test]
+		public async Task InsertFromSelectWithMultipleAssociationsAsync()
+		{
+			Assume.That(TestDialect.NativeGeneratorSupportsBulkInsertion,
+				"The dialect does not support a native generator compatible with bulk insertion.");
+
+			using var s = OpenSession();
+			using var tx = s.BeginTransaction();
+
+			await (s.CreateQuery("insert into Enrolment (Course, Student)" +
+				" select e.Course, e.Student from Enrolment e")
+				.ExecuteUpdateAsync());
+
+			await (tx.CommitAsync());
+		}
 	}
-}
+}

src/NHibernate.Test/BulkManipulation/Course.cs

@@ -0,0 +1,8 @@
+namespace NHibernate.Test.BulkManipulation
+{
+	public class Course
+	{
+		public virtual long CourseId { get; set; }
+		public virtual string Description { get; set; }
+	}
+}

src/NHibernate.Test/BulkManipulation/Enrolment.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace NHibernate.Test.BulkManipulation
+{
+	[Serializable]
+	public class Enrolment
+	{
+		public virtual long EnrolmentId { get; set; }
+		public virtual Student Student { get; set; }
+		public virtual Course Course { get; set; }
+	}
+}

src/NHibernate.Test/BulkManipulation/Enrolment.hbm.xml

@@ -0,0 +1,29 @@
+<?xml version="1.0"?>
+<hibernate-mapping
+	xmlns="urn:nhibernate-mapping-2.2"
+	assembly="NHibernate.Test"
+	namespace="NHibernate.Test.BulkManipulation">
+
+  <class name="Course">
+    <id name="CourseId">
+      <generator class="native" />
+    </id>
+    <property name="Description" />
+  </class>
+
+  <class name="Student">
+    <id name="StudentId">
+      <generator class="native" />
+    </id>
+    <property name="Name" />
+  </class>
+
+  <class name="Enrolment">
+    <id name="EnrolmentId">
+      <generator class="native" />
+    </id>
+    <many-to-one name="Student" column="StudentId" class="Student" />
+    <many-to-one name="Course" column="CourseId" class="Course" />
+  </class>
+
+</hibernate-mapping>

src/NHibernate.Test/BulkManipulation/HQLBulkOperations.cs

@@ -32,5 +32,21 @@ public void SimpleDelete()
 				tx.Commit();
 			}
 		}
+
+		[Test]
+		public void InsertFromSelectWithMultipleAssociations()
+		{
+			Assume.That(TestDialect.NativeGeneratorSupportsBulkInsertion,
+				"The dialect does not support a native generator compatible with bulk insertion.");
+
+			using var s = OpenSession();
+			using var tx = s.BeginTransaction();
+
+			s.CreateQuery("insert into Enrolment (Course, Student)" +
+				" select e.Course, e.Student from Enrolment e")
+				.ExecuteUpdate();
+
+			tx.Commit();
+		}
 	}
-}
+}

src/NHibernate.Test/BulkManipulation/Student.cs

@@ -0,0 +1,8 @@
+namespace NHibernate.Test.BulkManipulation
+{
+	public class Student
+	{
+		public virtual long StudentId { get; set; }
+		public virtual string Name { get; set; }
+	}
+}

src/NHibernate/Hql/Ast/ANTLR/Tree/SelectClause.cs

@@ -494,7 +494,7 @@ private void RenderNonScalarIdentifiers(
 				}
 
 				var node = (IASTNode) e;
-				if (processedElements.Add(fromElement))
+				if (Walker.IsShallowQuery && node.Type == SqlGenerator.DOT || processedElements.Add(fromElement))
 				{
 					combinedFromElements.Add(fromElement);
 					RenderNonScalarIdentifiers(fromElement, inheritedExpressions.ContainsKey(e) ? null : e, appender);