Until now we all agreed these were benefits of Cocoa: * C compatibility * Dynamic dispatch * Nil safety * Duck typing Now they're all bad?— Nick Lockwood (@nicklockwood) August 6, 2014
Okay, let’s take this one item at a time:
Having a more capable type system means we can lean on it instead of duck typing. For whatever it’s worth, I rarely used duck typing in Objective-C as it is; typically I either lean more heavily on the class hierarchy or introduce a protocol instead. (I may go into this in more detail in a later blog post.)
Will be missed, but it does appear Swift will somewhat handle this as well, and I would expect more developments in new language versions.