RFR: Classfile signature bang support [v2]

[Chen Liang]

On Wed, 21 Jan 2026 16:08:56 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

>> Chen Liang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
>> 
>>  - Review, various cleanup
>>  - Merge branch 'bworld' of https://github.com/openjdk/valhalla into feature/cf-bang-sig
>>  - Classfile signature bang support
>
> test/jdk/jdk/classfile/SignaturesTest.java line 411:
> 
>> 409:                 !Ljava/lang/Object;
>> 410:                 Ljava/lang/Object;!Ljava/lang/Runnable;
>> 411:                 <>Ljava/lang/Object;
> 
> This test line seems repeated? Or did you want to add a `!` here?

Replaced with `<T:!Ljava/lang/Number;>Ljava/lang/Object;` which tries to represent `<T extends Number!>`, currently illegal

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PR Review Comment: https://git.openjdk.org/valhalla/pull/1933#discussion_r2714210432