I'll trot out my favorite examples of the "development of doctrine". In Quanta Cura, Pius IX calls "liberty of conscience and worship" "an insanity". Vatican II's Dignitatis Humane says that this liberty is a fundamental right of all people. 

Pope Eugene IV wrote in Cantate Domino "all those who are outside the Catholic Church, not only pagans but also Jews or heretics and schismatics, cannot share in eternal life and will go into the everlasting fire which was prepared for the devil and his angels". Vatican II's Lumen Gentium said that essentially everyone, and it is specific about Jews, has at least the possibility of salvation.

In both cases, the latter teachings contradict the earlier ones. Doctrine can not only "develop", previous teaching can be outright reversed.