The language design contract is unsafe by default. In memory, types and concurrency. What are you talking about? There are unsafe blocks all over the stdlib. And concurrency safety would need to get rid of their blocking IO, which they haven't even acknowledged.
> There are unsafe blocks all over the stdlib
Physics is unsafe. Something, somewhere needs to provide the safe core.
> And concurrency safety would need to get rid of their blocking IO, which they haven't even acknowledged.
Is your position that blocking IO can't be compatible with concurrency safety? That's a strange claim. Can you explain?