Removed partially implemented support for Enumerable.Any with predicate. It wasn't using $elemMatch and full support requires lots more development and testing and most likely support in the server for new forms of $elemMatch (for example support $and and $or inside an $elemMatch). This will be reimplemented in a future release. See CSHARP-413.

Author: rstam

Driver/Linq/LinqToMongo.cs

@@ -30,16 +30,6 @@ namespace MongoDB.Driver.Linq
     /// </summary>
     public static class LinqToMongo
     {
-        /// <summary>
-        /// Represents an arbitrary item in an array value. Can only be used in LINQ queries.
-        /// </summary>
-        /// <param name="source">The array value.</param>
-        /// <returns>Throws an InvalidOperationException if called.</returns>
-        public static TSource Arbitrary<TSource>(this IEnumerable<TSource> source)
-        {
-            throw new InvalidOperationException("The LinqToMongo.Arbitrary method is only intended to be used in LINQ Where clauses.");
-        }
-
         /// <summary>
         /// Determines whether a sequence contains all of the specified values.
         /// </summary>

Driver/Linq/Translators/SelectQuery.cs

@@ -289,14 +289,7 @@ private IMongoQuery BuildAnyQuery(MethodCallExpression methodCallExpression)
                 }
                 else if (arguments.Length == 2)
                 {
-                    var sourceExpression = arguments[0];
-                    var lambda = (LambdaExpression)arguments[1];
-                    var parameter = lambda.Parameters[0];
-                    var body = lambda.Body;
-                    var arbitraryMethodInfo = typeof(LinqToMongo).GetMethod("Arbitrary").MakeGenericMethod(parameter.Type);
-                    var arbitraryMethodCallExpression = Expression.Call(arbitraryMethodInfo, sourceExpression);
-                    var modifiedBody = ExpressionParameterReplacer.ReplaceParameter(body, parameter, arbitraryMethodCallExpression);
-                    return BuildQuery(modifiedBody);
+                    throw new NotSupportedException("Enumerable.Any with a predicate is not supported.");
                 }
             }
             return null;
@@ -919,25 +912,9 @@ private BsonSerializationInfo GetSerializationInfo(IBsonSerializer serializer, E
             }
 
             var methodCallExpression = expression as MethodCallExpression;
-            if (methodCallExpression != null)
+            if (methodCallExpression != null && methodCallExpression.Method.Name == "get_Item")
             {
-                switch (methodCallExpression.Method.Name)
-                {
-                    case "Arbitrary":
-                        if (methodCallExpression.Method.DeclaringType == typeof(LinqToMongo))
-                        {
-                            var arraySerializationInfo = GetSerializationInfo(serializer, methodCallExpression.Arguments[0]);
-                            var itemSerializationInfo = arraySerializationInfo.Serializer.GetItemSerializationInfo();
-                            return new BsonSerializationInfo(
-                                arraySerializationInfo.ElementName,
-                                itemSerializationInfo.Serializer,
-                                itemSerializationInfo.NominalType,
-                                itemSerializationInfo.SerializationOptions);
-                        }
-                        break;
-                    case "get_Item":
-                        return GetSerializationInfoGetItem(serializer, methodCallExpression);
-                }
+                return GetSerializationInfoGetItem(serializer, methodCallExpression);
             }
 
             return null;

DriverOnlineTests/Linq/SelectQueryTests.cs

@@ -1926,26 +1926,13 @@ where c.A.Any()
         }
 
         [Test]
+        [ExpectedException(typeof(NotSupportedException), ExpectedMessage = "Enumerable.Any with a predicate is not supported.")]
         public void TestWhereAAnyWithPredicate()
         {
             var query = from c in _collection.AsQueryable<C>()
                         where c.A.Any(a => a > 3)
                         select c;
-
-            var translatedQuery = MongoQueryTranslator.Translate(query);
-            Assert.IsInstanceOf<SelectQuery>(translatedQuery);
-            Assert.AreSame(_collection, translatedQuery.Collection);
-            Assert.AreSame(typeof(C), translatedQuery.DocumentType);
-
-            var selectQuery = (SelectQuery)translatedQuery;
-            Assert.AreEqual("(C c) => Enumerable.Any<Int32>(c.A, (Int32 a) => (a > 3))", ExpressionFormatter.ToString(selectQuery.Where));
-            Assert.IsNull(selectQuery.OrderBy);
-            Assert.IsNull(selectQuery.Projection);
-            Assert.IsNull(selectQuery.Skip);
-            Assert.IsNull(selectQuery.Take);
-
-            Assert.AreEqual("{ \"a\" : { \"$gt\" : 3 } }", selectQuery.BuildQuery().ToJson());
-            Assert.AreEqual(1, Consume(query));
+            query.ToList(); // execute query
         }
 
         [Test]