Algebraic effects could help a lot. They let you quickly discard giant swaths of pure code, or even impure code that's surely harmless because its effects are l

Algebraic effects could help a lot. They let you quickly discard giant swaths of pure code, or even impure code that's surely harmless because its effects are limited to, say, graphics or audio output, and focus on the operations that use sensitive things like the file store, the internet, etc.