We've had various users reach out to us for help when they run into deserialization errors using our Serde integration. This is often because they end up with some sort of inconsistent data in their DB that cannot be deserialized to their defined type, and they don't understand or cannot diagnose the problem just from the error message.

We should try to help them out by making the deserialization errors we have control over as descriptive as we can.

For one set of candidates, all of the errors here could be updated such that if the incorrect BSON type is found, we report what we found instead.