[danenania]

These seem like solvable problems. Prototype modifications are rare these days and should probably be restricted in the same way that system/network access is. Shared objects between modules also seem like an edge case apart from callbacks? I posted an idea on how to handle callbacks upthread a bit: https://news.ycombinator.com/item?id=31326123#31332061

[zdragnar]

System and network access are all done via the runtime library functions, which are easy to control.

Changing prototype access almost certainly involves modifying V8 in unpleasant ways, and I'm not sure how you would get around the overhead of deno needing to the call stack on every function call- statically analyzing when a function is operating in one context or another is certainly not a trivial problem.