I don't understand the controversy or objections, though maybe I'm missing something. This looks like Ada-2012 contracts which evolved from SPARK Ada going back to near-ancient times. They're well accepted I thought. The idea is to standardize the syntax so that static analyzers can check the contracts, like in Ada. I think Rust is getting something similar. It seems important. Maybe the DIS was rejected because there are still disagreements about some details, ok fine. But rejecting the whole feature sounds counterproductive to keeping C++ relevant. Assuming that last is a good thing, of course.