Very confused about some compiler warnings related to protocols—bugs or intended?

[1oo7 (J. Shad.)]

@jonprescott

Well, if you care about cross-platform, @obj protocols are not supported for anything other than Darwin. The obj runtime get involved would be another difference

Ah, good callout. I'll add it to the table.

[Nobody1707]

Potentially someone could add such support to another system with an Objective-C runtime, like GNUStep or Windows, but that doesn't seem likely in the foreseeable future.