Hacker News Reader

Rust has documentation which describes how it's supposed to behave, which is a far cry from everything being undefined behavior. It also has a formal specification of a subset of the language.

It's not like the C/C++ specs are particularly precise. I think people tend to have a mental model of specs as equivalent to formal semantics, which they very much are not.

You should check out https://news.ycombinator.com/item?id=20105996

And I think it’s a bit more subtle than you’re giving credit for.

That wouldn't mean that all of Rust is undefined behavior, it means the compiler is the spec, and the behavior is defined by what the compiler will do. The language having no specification only means that you can't easily determine if what the compiler does is "technically correct", but that's always secondary to the matter of whether the compiler does what you actually want.