It's not difficult to have a Special Purpose language with no UB. There isn't any UB in WUFFS (a language for Wrangling Untrusted File Formats Safely) for examp

It's not difficult to have a Special Purpose language with no UB. There isn't any UB in WUFFS (a language for Wrangling Untrusted File Formats Safely) for example. Those "dark corners" come into the picture when you decide you want a General Purpose language. When your program might actually intend to respond to emails by executing the x86-64 machine code squirrelled away inside this logo PNG and running the output as SQL on your customer database, it's not possible for the language to ensure that programs which weren't intended to do that can't do that, how would they know? The translator isn't a mind reader, your intent is unreadable. I think we should use general purpose languages much less often, the industry doesn't seem to agree, the results are obvious for everyone to see. Rust has a subset, "safe Rust" which isn't a fully general purpose language but deliberately shares its syntax with a larger unsafe Rust you can use when it turns out that you needed it. Safe Rust doesn't have UB.