Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System.Data.Entity/System/Data/Query/InternalTrees/RulePatternOps.cs

@@ -0,0 +1,40 @@
+//---------------------------------------------------------------------
+// <copyright file="RulePatternOps.cs" company="Microsoft">
+//      Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//
+// @owner  [....]
+// @backupOwner [....]
+//---------------------------------------------------------------------
+
+using System;
+using System.Collections.Generic;
+using System.Data.Metadata.Edm;
+using System.Globalization;
+
+namespace System.Data.Query.InternalTrees
+{
+    /// <summary>
+    /// LeafOp - matches any subtree 
+    /// </summary>
+    internal sealed class LeafOp : RulePatternOp
+    {
+        /// <summary>
+        /// The singleton instance of this class
+        /// </summary>
+        internal static readonly LeafOp Instance = new LeafOp();
+        internal static readonly LeafOp Pattern = Instance;
+
+        /// <summary>
+        /// 0 children
+        /// </summary>
+        internal override int Arity { get { return 0; } }
+
+        #region constructors
+        /// <summary>
+        /// Niladic constructor
+        /// </summary>
+        private LeafOp() : base(OpType.Leaf) { }
+        #endregion
+    }
+}