added MongoIdAttribute

source/MongoDB/Attributes/MongoAliasAttribute.cs

@@ -21,6 +21,9 @@ public sealed class MongoAliasAttribute : Attribute
         public MongoAliasAttribute(string name){
             if(name == null)
                 throw new ArgumentNullException("name");
+            if (name == "_id")
+                throw new ArgumentException("_id is a reserved alias.");
+
             Name = name;
         }
     }

source/MongoDB/Attributes/MongoIdAttribute.cs

@@ -0,0 +1,17 @@
+using System;
+
+namespace MongoDB.Attributes
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Property)]
+    public sealed class MongoIdAttribute : Attribute
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="MongoIdAttribute"/> class.
+        /// </summary>
+        public MongoIdAttribute()
+        { }
+    }
+}

source/MongoDB/Configuration/Mapping/Auto/AutoMappingProfile.cs

@@ -95,7 +95,16 @@ public MemberInfo FindExtendedPropertiesMember(Type classType)
         /// <returns></returns>
         public MemberInfo FindIdMember(Type classType)
         {
-            return _conventions.IdConvention.GetIdMember(classType);
+            var members = (from memberInfo in _memberFinder.FindMembers(classType)
+                          let att = memberInfo.GetCustomAttribute<MongoIdAttribute>(true)
+                          where att != null
+                          select memberInfo).ToList();
+
+            if (members.Count > 1)
+                throw new InvalidOperationException("Cannot have more than 1 member marked with a MongoId Attribute.");
+            if(members.Count == 0)
+                return _conventions.IdConvention.GetIdMember(classType);
+            return members[0];
         }
 
         /// <summary>

source/MongoDB/Linq/Translators/QueryBinder.cs

@@ -273,6 +273,18 @@ private Expression BindAggregate(Expression source, MethodInfo method, LambdaExp
             return subquery;
         }
 
+        private Expression BindAny(Expression source, LambdaExpression predicate)
+        {
+            var projection = VisitSequence(source);
+            _map[predicate.Parameters[0]] = projection.Projector;
+            var where = Visit(predicate.Body);
+            var alias = new Alias();
+            var fieldProjection = _projector.ProjectFields(projection.Projector, alias, projection.Source.Alias);
+            return new ProjectionExpression(
+                new SelectExpression(alias, fieldProjection.Fields, projection.Source, where),
+                fieldProjection.Projector);
+        }
+
         private Expression BindDistinct(Expression source)
         {
             var projection = VisitSequence(source);

source/MongoDB/MongoDB.csproj

@@ -102,6 +102,7 @@
     <Compile Include="..\..\AssemblyInfoGlobal.cs">
       <Link>AssemblyInfoGlobal.cs</Link>
     </Compile>
+    <Compile Include="Attributes\MongoIdAttribute.cs" />
     <Compile Include="BinarySubtype.cs" />
     <Compile Include="Bson\BsonType.cs" />
     <Compile Include="Bson\BsonInfo.cs" />