A stricter, faster subset of JS would be very welcome, which seems to be what the unshared struct part of this proposal provides. By the way, doesn't V8's opti

A stricter, faster subset of JS would be very welcome, which seems to be what the unshared struct part of this proposal provides. By the way, doesn't V8's optimizer already do something like this internally? I read one of their tech blogs back in the day that explained how they analyze the structure of objects and whenever possible, compile it to the equivalent of a C++ class. I guess doing it explicitly makes the optimizer's job much easier -- the more guarantees you give it about what won't happen, the more optimizations it's free to make.