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

[Karen Kinnear]

Brian,

This was a request for LW2 - no more boxing. 
We asked for the subtype relationship for both values and for arrays.

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    - The old .box and .val notation is not withdrawn yet and can still be used, but we should really move over to the new syntax as soon as possible.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
>>> 
>> 
>