This would be tremendously powerful if primitive “colors” automatically label (or poison) any data structures they are placed into, and one can guard against ce

This would be tremendously powerful if primitive “colors” automatically label (or poison) any data structures they are placed into, and one can guard against certain colors being used in specific places. And casting to override this requires specific keywords that can be caught in audits. For instance, a password can never leak to logging or a client response. An unescaped user input can never leak to a client response unless explicitly casted - and user provided data from a database counts this way too!