5 ms·

But an object constructed from a class still has all the optimisation problems you just mentioned. It’s just syntactic sugar. The optimiser generates invariants

• tehbeard 5y ago
  The syntactic sugar is something the optimiser is aware of and isn't just a "do this in a more pretty/stylised way" for the developer, it conveys an intent that this is a construct that can be optimized with a certain level of confidence that you can't get from objects that "look like a duck and quack like a duck" if you squint a little. And if anything happens that does "deoptimize" it, then if we know the "base" is definitely a class, the paths to handle the "deoptimization" can make better decisions and be able to avoid scrapping everything and falling back to the slow path.