RFR: 8302344: Compiler Implementation for Unnamed patterns and variables (Preview) [v15]

[Joe Darcy]

On Fri, 5 May 2023 16:01:00 GMT, Aggelos Biboudis <abimpoudis at openjdk.org> wrote:

>> This PR implements [JEP 443](https://openjdk.org/jeps/443), the preview feature for Unnamed Patterns and Variables in Java.
>> 
>> Draft Spec: https://cr.openjdk.org/~abimpoudis/unnamed/latest/
>
> Aggelos Biboudis has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Address comments
>   
>   - Annotate with Preview
>   - Fix isUnnamed hierarchy
>   - Flow names.empty for underscore in both model and API
>   - Adjust pretty printing and annotation pretty printing
>   - Fix guard bindings (great catch and thx @lahodaj!)
>   - Fix TreeVisitor
>   - Remove test with lambda which has a parse error from VarTree (names.empty is used to signal error)
>   - Various adjustments
>   
>   Co-authored-by: Jan Lahoda <jan.lahoda at oracle.com>

src/jdk.compiler/share/classes/com/sun/tools/javac/code/Symbol.java line 1788:

> 1786:         }
> 1787: 
> 1788:         @Override @DefinedBy(Api.LANGUAGE_MODEL)

It's not incorrect to have this override, but I don't think it is necessary now either with the update to the default method.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13528#discussion_r1186509423