hg: valhalla/valhalla: 8221545: [lworld] Preliminary support for alternate denotation of values and boxes

[Srikanth]

This change set just introduces the new notation doing nothing new about 
inserting casts.
I will go through the mails discussing this and follow up on a different 
change set.

Thanks
Srikanth
On 16/04/19 7:32 PM, Brian Goetz wrote:
>> This was a request for LW2 - no more boxing.
> Right.  I was wondering whether we got there yet, or whether we’d just change the notation to start.
>
>> We asked for the subtype relationship for both values and for arrays.
> For arrays, the covariance rule: T <: U imples T[] <: U[] — should hold uniformly.  No need for special exceptions for value arrays.  Since
>
>      V <: Object
> and
>      V? <: Object
>
> then both V[] and V?[] are <: Object[].
>
>
>
>> For LW2 - we requested explicit checkcasts on attempts to narrow.
>>
>> Agreed that there are discussions about where this is all going after LW2 before LW10.
>>
>> thanks,
>> Karen
>>
>>> On Apr 16, 2019, at 9:24 AM, Brian Goetz <brian.goetz at oracle.com> wrote:
>>>
>>> Is the conversion from V to V? still considered a boxing conversion, or is it a widening conversion now?  The language we (currently think we) want is
>>>
>>>   V <: V?
>>>
>>> In the other direction, we’re still discussing whether the narrowing conversion is implicit or explicit.
>>>
>>>> On Apr 16, 2019, at 8:09 AM, Srikanth <srikanth.adayapalam at oracle.com> wrote:
>>>>
>>>> Notes:
>>>>
>>>>    - This is the initial commit for supporting V? notation as an alternate for V.box
>>>>    - The old .box and .val notation is not withdrawn yet and can still be used, but we should really move over to the new syntax as soon as possible.
>>>>    - Existing javac tests have been replicated to use the V? syntax.
>>>>    - VBC migration related work is not done yet.
>>>>    - One issue that showed up in the parser implementation is the ambiguity at the point of seeing ?
>>>>       in  v instanceof Type? exp: exp2; I have arranged for this to be processed as a conditional rather
>>>>       than as denoting nullability.
>>>>    - On a long value type name the ? suffix does not really stand out ATM, but I guess IDE colorcoding can address this issue.
>>>>    - There is one failing test in the langtools suite (jdk/jshell/TypeNameTest.java) I will raise a follow up
>>>>      ticket to address this.
>>>>    - More testing is required and will be undertaken in the coming weeks. I request/encourage testing by the interested parties too.
>>>>
>>>> Thanks!
>>>> Srikanth
>>>>
>>>> On 16/04/19 5:32 PM, srikanth.adayapalam at oracle.com wrote:
>>>>> Changeset: bf52db1ad4ea
>>>>> Author:    sadayapalam
>>>>> Date:      2019-04-16 17:31 +0530
>>>>> URL:       http://hg.openjdk.java.net/valhalla/valhalla/rev/bf52db1ad4ea
>>>>>
>>>>> 8221545: [lworld] Preliminary support for alternate denotation of values and boxes
>>>>>
>>>>> ! src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java
>>>>> ! src/jdk.compiler/share/classes/com/sun/tools/javac/comp/AttrContext.java
>>>>> ! src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Resolve.java
>>>>> ! src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavacParser.java
>>>>> ! src/jdk.compiler/share/classes/com/sun/tools/javac/tree/JCTree.java
>>>>> ! src/jdk.compiler/share/classes/com/sun/tools/javac/tree/TreeCopier.java
>>>>> ! test/langtools/tools/javac/valhalla/lworld-values/BogusIncompatibility.java
>>>>> + test/langtools/tools/javac/valhalla/lworld-values/BoxValCastTest2.java
>>>>> + test/langtools/tools/javac/valhalla/lworld-values/GenericsWithQuestion.java
>>>>> + test/langtools/tools/javac/valhalla/lworld-values/GenericsWithQuestion.out
>>>>> ! test/langtools/tools/javac/valhalla/lworld-values/InnerClassAttributeValuenessTest.java
>>>>> + test/langtools/tools/javac/valhalla/lworld-values/IntercastTest2.java
>>>>> + test/langtools/tools/javac/valhalla/lworld-values/LookupOnLoxTest2.java
>>>>> ! test/langtools/tools/javac/valhalla/lworld-values/Point.java
>>>>>