Comment How much safety does this give? (Score 1) 1
It obviously gives us guarantees in terms of what the source will do and what the compiled code should need.
These do not provide memory safety, so memory bugs would not be solved by these. They will find unexpected behavioural issues, though.
The precondition and postcondition statements are not cunningly-disguised assert statements because they're not asserted at runtime. They're enforced at static check and/or compile time.
The policy hints mean that if the kernel is doing something you're not expecting, you find this when testing the code. Equally, though, it means that users cannot cause the software to venture into realms unknown through many of the usual attack vectors because those will require permissions that aren't there.