I have typically understood the "Sufficiently Smart Compiler" to be one that can arrive at the platonic performance ideal of some procedure, regardless of how the steps in that procedure are actually expressed (as long as they are technically correct). This is probably impossible.
What I'm proposing is quite a bit more reasonable—so reasonable that versions of it exist in various ecosystems. I just think they can be better and am essentially thinking out loud about how I'd like that to work.
I'm fully on board with improving compilers. My issue is that you compare the current state of (some) dynamically-typed languages with a hypothetical future state of statically-typed languages.
You use `req.cookies['token']` as an example of a subtle bug in JavaScript, but this isn't necessarily an inherent bug to dynamic typing in general. You could, for example, have a key lookup function that requires you to pass in a default value, or callback to handle what occurs if the value is missing.
req.cookies.get('token', () => {
throw new AuthFailure("Missing token")
})
What I'm proposing is quite a bit more reasonable—so reasonable that versions of it exist in various ecosystems. I just think they can be better and am essentially thinking out loud about how I'd like that to work.