Are value types supposed to work at all currently?

Brian Goetz brian.goetz at
Tue May 19 15:41:33 UTC 2015

> I guess I will have to change the concept of the talk for tomorrow then...
> Do you think there will be any considerable changes to the state of the
> implementation of value types until 8th of June? (ScalaDays Amsterdam)
> Or should I assume that there is nothing I can run, and plan the talk
> accordingly?

That's what we've been doing :)

There's lots to talk about in terms of possible directions.  You can 
easily talk for 10-15 minutes just on the hardware trends motivating the 
need for better control over flattening, and the toxicity of pervasive 

> Can you speak about whether the bytecode emitted by javac for value types is
> roughly what we will probably end up?

It is definitely too early to tell.  What is emitted now is definitely 
not right (it's all a* bytecodes at the back end, so we model values 
with classes, the only thing the compiler prototype does now is enforce 
things like "can't lock on a value" and "can't assign null to a value.") 
  The real question for values is, what *will* the bytecodes look like? 
  We're investigating several options, including the one laid out in the 

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