Priests will not violate the seal of confession even in the case of the sexual abuse of a child. And, in no jurisdiction that I'm aware of are they required by law to do so.
Perhaps they won't violate the confession, but there are some State laws that say they must in certain cases. I suppose enforcement might be tough, but I don't see where I would lose much sleep if I heard a priest turned in a child molester. Why should a creep get to unload his/her guilt at the expense of someone else? I guess that's why I prefer the Bible as the final Word rather than the religions of the world.
This link Discussion about confession confidentiality is just one of many available to let you know that some religious practices/covenants may not be given full deference in all cases.