Attempting to perform an update operation using the positional operator and an indexed query fails.

I have verified that this same example worked under 2.0.0.

Example: [Starting with an empty database]

MongoDB shell version: 2.1.0
...
> db.test.save( { ArrayField : [

{ Name : "First", Count : 1 }

] } )
> db.test.update(

{ "ArrayField.Name" : "First" }

, { $inc :

{ "ArrayField.$.Count" : 1 }

} )
> db.test.find()
{ "_id" : ObjectId("4f47b2bb78da8386a67102c7"), "ArrayField" : [

{ "Name" : "First", "Count" : 2 }

] }
> db.test.ensureIndex(

{ "ArrayField.Name" : 1 }

)
> db.test.update(

{ "ArrayField.Name" : "First" }

, { $inc :

{ "ArrayField.$.Count" : 1 }

} )
can't append to array using string field name [$]