Lets say I have the below record in the `Groups` collection:
```

{ "_id" : ObjectId("5899aa7cf226640ba4023c8f"), "members" : [ "a", "b" ] }

```
Then if I do query like this, then it works fine:
```
db.Groups.find({
members:

{ $size: 2, $all: ['a', 'b'] }

})
```

But if I do query like this:
```
db.Groups.find({
members:

{ $size: 2, $all: ['b', 'ba] }

})
```
Then I will get this error, quite surprised:
```
{ MongoError: exception: cannot infer query fields to set, path 'members' is matched twice
at Function.MongoError.create (/app/node_modules/mongodb-core/lib/error.js:31:11)
at /app/node_modules/mongodb-core/lib/connection/pool.js:483:72
at authenticateStragglers (/app/node_modules/mongodb-core/lib/connection/pool.js:429:16)
at Connection.messageHandler (/app/node_modules/mongodb-core/lib/connection/pool.js:463:5)
at Socket.<anonymous> (/app/node_modules/mongodb-core/lib/connection/connection.js:319:22)
at emitOne (events.js:96:13)
at Socket.emit (events.js:188:7)
at readableAddChunk (_stream_readable.js:176:18)
at Socket.Readable.push (_stream_readable.js:134:10)
at TCP.onread (net.js:548:20)
name: 'MongoError',
message: 'exception: cannot infer query fields to set, path \'members\' is matched twice',
errmsg: 'exception: cannot infer query fields to set, path \'members\' is matched twice',
code: 54,
ok: 0,
'$gleStats':
{ lastOpTime: Timestamp

{ _bsontype: 'Timestamp', low_: 0, high_: 0 }

,
electionId: 589c42b7d4fababa657fa1c2 } }
```