Yeah it's not the segfault that's bad, it's when it's when the write to address 0x20001854 succeeds and now some hapless postal clerk is going to jail.
I guess I was thinking specifically of the swift case where values have exclusive access enforcement. Normally caught by a compiler, they will safely crash if the compiler didn’t catch it. I think the only way to segfault would be by using Unsafe*Pointer types, which are explicitly marked unsafe