Hey, maybe you're the right person to ask - why does `arguments` so easily deoptimize in every major engine (well, V8 and SpiderMonkey, at least)?

It seems that engines could easily detect the most common munging of `arguments` (such as [].slice.call(arguments), Array.prototype.slice.call(arguments). Array.from(arguments) and the like) and allow those to be optimized. Doing so would speed up a very large amount of code.

Do you have any insight on why that still has not been done after so many years?