I'm not sure I understand what you're getting at here.

Are you implying that people who want new features in C should just migrate to C++ because it has even more features? Or that C is perfect as-is and anyone who wants to add new features to it should bug off to another language? Or that this particular feature is somehow equivalent to (or a slippery slope toward) adding a whole set of OOP features to C, so we might as well take that to its logical conclusion?

Pretty much all of the above.

I'd like to hear you elaborate. You seem to be very invested in your concerns, but it's hard to understand exactly what they are.

A single, clearly articulated response would do a lot more than a fusillade of terse barbs to help others understand why you think this is a bad idea.