[steveklabnik]

One example is integer ranges; they'd be a runtime check in Rust right now. We'll get there. That said, in general, Rust's type safety stuff is fairly powerful, and IIRC has some things that Ada does not.

I do think your parent isn't fully right about the relationship though, as first they call Rust a "subset" of Ada's guarantees, but then say that Ada doesn't go so far as Rust in some places. In general, when discussing language semantics, I see them as more of a large overlap with some differences on each side, rather than one being a subset of the other.