[lworld] RFR: 8263900: [lworld] Make .default a separate node type in the parser.

[Srikanth Adayapalam]

On Tue, 23 Mar 2021 10:47:34 GMT, Srikanth Adayapalam <sadayapalam at openjdk.org> wrote:

>> Thanks Jesper, I will review this one and help you take it forward.
>
> I have made one high level pass over the changes, more verifying on the boiler plate parts. Need to delve deeper in Attr, Gen, Parser, TransValues, will do this tomorrow.
> 
> Here are some comments so far:
> 
> (1) Is DefaultExpression better named as DefaultInstance or DefaultValue ??
> (2) Should com.sun.tools.javac.tree.JCTree.JCDefaultExpression#getClazz - for consistency sake return JCExpression ??
> (compare similar cases in JCTree)
> (3) Do we need a visitor in SourceComputer in CRTable.java ??

Here are cumulative comments:

(1) Is DefaultExpression better named as DefaultInstance or even better DefaultValue ??
(2) Should com.sun.tools.javac.tree.JCTree.JCDefaultExpression#getClazz - for consistency sake return JCExpression ??
(compare similar cases in JCTree)
(3) Should JCDefaultExpression#getClazz be named getType() a la JCTypeCast, JCNewArray, JCVariableDecl, JCInstanceof ...
(4) Do we need a visitor in SourceComputer in CRTable.java ??
(5) Attr.java:4464: reference to .default needs to be removed from comment
(6) Attr.visitDefaultExpression: sitesym seems to be unused variable declaration.
(7) This program: 
primitive class X {
    Object o2 = java.util.default;
}

generates this strange error: 
error: package java does not exist
    Object o2 = java.util.default;
                               ^
1 error
(That it emits the same message without the patch notwithstanding)

I think we should attribute the clazz as a TYP_PCK and for package case emit an error.
(8) com.sun.source.util.TreeScanner#visitDefaultExpression: Eliminate the local and directly return ?
 
Let me know if you have any questions/clarifications.

Thanks for your effort, this looks very promising prework for the poly expr typing task

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PR: https://git.openjdk.java.net/valhalla/pull/370