mongoid/origin — pull request #44 by flexoid (2012-08-31 23:44:14+00:00)
Title: Serialize deeply nested selector correctly

For example:
{'$and' => [{'$or' => [{_id: '50412b6b555389e152000002'}]}]}

Before we will always get nothing because '_id' serialized as string.
Now it is serialized into ObjectId regardless of the level of nesting.