hg: valhalla/valhalla: 8222634: [lworld] Javac sometimes emits incorrect ('Q') descriptors for fields.

[Brian Goetz]

Great.  Note that null-default is for L20, not L10, so perhaps we should work that in a dependent branch?  

> On Apr 17, 2019, at 10:02 AM, Srikanth <srikanth.adayapalam at oracle.com> wrote:
> 
> 
> 
> On 17/04/19 6:43 PM, Brian Goetz wrote:
>>>> (1) Compile time null assignment to values should be tolerated (?)
>>>> (2) Compiler does not tolerate the following:
>>>> MyValue1?[] vBoxArray = new MyValue1?[42];
>>> On (1) can I get a quick confirmation that this is what we want ? I did see some discussion regarding javac not proactively catching these and letting the VM report an NPE. But I seem to have missed the rationale behind that decision against failing early.
>> On (1), I think this should be done on the basis of value set inclusion.  For reference types, null-default value types, and the nullable-projection of zero-default value types (V?), null is a member of the value set; for primitives, and for zero-default value types, it is not.  I think the compiler should not allow assignment of a value that is not a member of the value set.
> 
> Perfect. I must have misread a private communication from one of the contributors that ATM I am unable to locate, but your outline clarifies the questions I had.
> 
> javac does not yet have a notion of null default value types. Other than that the tip behavior should match what describe above. I have half a dozen smallish tasks to wrap the various loose ends and also test the V? implementation more and after that I will start on the null default value types.
> 
> Thanks
> Srikanth
>> 
>> We need better terminology….I said value and null too many times in the above paragraph.
>