RFR: 8256266: Binding variables don't correct support declaration annotations and the final modifier [v3]

[Maurizio Cimadamore]

On Mon, 7 Dec 2020 11:21:26 GMT, Jan Lahoda <jlahoda at openjdk.org> wrote:

>> Basically, javac does not handle code like this properly:
>> 
>> import java.lang.annotation.*;
>> 
>> public class B {
>>      public void test(Object o) {
>>          if (o instanceof @A String s) {}
>>      }
>> }
>> 
>> @Target(ElementType.LOCAL_VARIABLE)
>> @interface A {}
>> 
>> The parser needs to allow declaration annotations on binding variables, see:
>> http://cr.openjdk.java.net/~gbierman/jep394/jep394-20201012/specs/patterns-instanceof-jls.html#jls-14.30.1.1
>
> Jan Lahoda has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fixing tests.

Changes look good - I just have a question on the parser code

src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavacParser.java line 946:

> 944:                     TreeInfo.getStartPos(pattern);
> 945:                 } else {
> 946:                     if (mods.annotations.nonEmpty()) {

We don't seem to check for the source level here? E.g. is it possible that `instanceof @Foo Bar` will not issue the usual error if compiled with source != 16?

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PR: https://git.openjdk.java.net/jdk/pull/1192