In almost every project I work in, I use at least five 3rd party libraries. “Treating warnings as errors” is no longer practical for me.
I try to contribute when I can, but on my best months I can only submit a few patches. Who has time to contribute every open source library they use just to get rid of warnings?
Projects like cocoa pods are attempting to help with some of this, but they are still is a long way off.
Many developers say “Warnings are there for a reason, don’t ignore them”. Let me turn that argument on it’s head - Warnings are not errors for a reason, so you ship.