Use proper inner join in Linq instead of cross-join and where clauses

Author: hazzik

Diff for: src/NHibernate/Hql/Ast/HqlTreeBuilder.cs

@@ -363,6 +363,11 @@ public HqlJoin Join(HqlExpression expression, HqlAlias @alias)
 			return new HqlJoin(_factory, expression, @alias);
 		}
 
+		public HqlInnerJoin InnerJoin(HqlExpression expression, HqlAlias @alias)
+		{
+			return new HqlInnerJoin(_factory, expression, @alias);
+		}
+
 		public HqlAny Any()
 		{
 			return new HqlAny(_factory);

Diff for: src/NHibernate/Hql/Ast/HqlTreeNode.cs

@@ -822,9 +822,18 @@ public HqlJoin(IASTFactory factory, HqlExpression expression, HqlAlias @alias) :
 		}
 	}
 
+	public class HqlInnerJoin : HqlTreeNode
+	{
+		public HqlInnerJoin(IASTFactory factory, HqlExpression expression, HqlAlias @alias) 
+			: base(HqlSqlWalker.JOIN, "join", factory, new HqlInner(factory), expression, @alias)
+		{
+		}
+	}
+
 	public class HqlLeftJoin : HqlTreeNode
 	{
-		public HqlLeftJoin(IASTFactory factory, HqlExpression expression, HqlAlias @alias) : base(HqlSqlWalker.JOIN, "join", factory, new HqlLeft(factory), expression, @alias)
+		public HqlLeftJoin(IASTFactory factory, HqlExpression expression, HqlAlias @alias)
+			: base(HqlSqlWalker.JOIN, "join", factory, new HqlLeft(factory), expression, @alias)
 		{
 		}
 	}
@@ -876,6 +885,14 @@ public HqlBitwiseAnd(IASTFactory factory, HqlExpression lhs, HqlExpression rhs)
 		}
 	}
 
+	public class HqlInner : HqlTreeNode
+	{
+		public HqlInner(IASTFactory factory)
+			: base(HqlSqlWalker.LEFT, "inner", factory)
+		{
+		}
+	}
+
 	public class HqlLeft : HqlTreeNode
 	{
 		public HqlLeft(IASTFactory factory)

Diff for: src/NHibernate/Linq/Visitors/QueryModelVisitor.cs

@@ -346,7 +346,7 @@ public override void VisitNhJoinClause(NhJoinClause joinClause, QueryModel query
 			HqlTreeNode hqlJoin;
 			if (joinClause.IsInner)
 			{
-				hqlJoin = _hqlTree.TreeBuilder.Join(expression, alias);
+				hqlJoin = _hqlTree.TreeBuilder.InnerJoin(expression, alias);
 			}
 			else
 			{
@@ -497,15 +497,17 @@ public override void VisitOrderByClause(OrderByClause orderByClause, QueryModel
 
 		public override void VisitJoinClause(JoinClause joinClause, QueryModel queryModel, int index)
 		{
+			var querySourceName = VisitorParameters.QuerySourceNamer.GetName(joinClause);
 			var equalityVisitor = new EqualityHqlGenerator(VisitorParameters);
 			var whereClause = equalityVisitor.Visit(joinClause.InnerKeySelector, joinClause.OuterKeySelector);
 
-			_hqlTree.AddWhereClause(whereClause);
-
-			_hqlTree.AddFromClause(
-				_hqlTree.TreeBuilder.Range(
-					HqlGeneratorExpressionVisitor.Visit(joinClause.InnerSequence, VisitorParameters),
-					_hqlTree.TreeBuilder.Alias(joinClause.ItemName)));
+			var expression = HqlGeneratorExpressionVisitor.Visit(joinClause.InnerSequence, VisitorParameters).AsExpression();
+			var hqlJoin = _hqlTree.TreeBuilder.InnerJoin(
+				expression,
+				_hqlTree.TreeBuilder.Alias(querySourceName)
+			);
+			hqlJoin.AddChild(_hqlTree.TreeBuilder.With(whereClause.ToBooleanExpression()));
+			_hqlTree.AddFromClause(hqlJoin);
 		}
 
 		public override void VisitGroupJoinClause(GroupJoinClause groupJoinClause, QueryModel queryModel, int index)