[Investigation] Use pattern matching for instanceof at module jdk.compiler

[Guoxiong Li]

Hi all,

The JEP-394[1] implemented the `Pattern matching for instanceof` at JDK 16.
It is a good specification. Many packages or modules of the JDK begin to
use it, such as package `java.time`[2][3]. I think it is good for the javac
compiler to use it, too.

Here are some issues we need to consider or something I want to confirm.

1. What's your opinion about this idea? Is it necessary?
2. Is somebody doing the same thing locally? If not, I would like to do
that.
3. Is it good to revise the whole module `jdk.compiler` by submitting a big
patch? Or, should we separate it into several sub-tasks according to
different packages?
4. Do the related modules, such as `java.compiler`, also need to be revised?

Any idea is appreciated.

[1] https://openjdk.java.net/jeps/394
[2] https://bugs.openjdk.java.net/browse/JDK-8263668
[3] https://github.com/openjdk/jdk/pull/3170

----
Best Regards,
Guoxiong
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.java.net/pipermail/compiler-dev/attachments/20210422/fd26b7fc/attachment.htm>