> That will also put it on the unfortunate position of being the place that breaks every time somebody adds a bug to the C code.

Can someone explain charitably what the poster is getting at? To me, the above makes zero sense. If the Rust code is what is implemented correctly, and has the well-defined semantics, then, when the C code breaks, it's obviously the C code's problem?

I think a charitable interpretation is that given that the Rust code will be less forgiving, it will "break" C code and patterns that "used to work", albeit with latent UB or other nonobvious correctness issues. Now, obviously this is ultimately a good thing, and no developer worth their salt would seriously argue that latent bugs should stay latent, but as we've already seen, people have egos and aren't always exceedingly rational.