RFR: 8342967: Lambda deduplication fails with non-metafactory BSMs and mismatched local variables names [v2]

[Maurizio Cimadamore]

On Thu, 24 Oct 2024 22:14:40 GMT, Aggelos Biboudis <abimpoudis at openjdk.org> wrote:

>> After experimentation and under certain conditions, a few equivalent lambdas (up to variable renaming) fail to deduplicate.
>> 
>> `TreeHasher` and `TreeDiffer` are now aware that other bootstraps may appear in lambda bodies (e.g. `SwitchBootstraps.typeSwitch`) and that variable names do not matter (when they appear in method/lambda definitions). In the first case equivalence is checked based on `bsmKey` and not the `Dynamic{Var, Method}Symbol` itself.
>> 
>> The test was also adjusted since it was assuming BSM with certain structure only (that `.get(1)` was unprotected).
>
> Aggelos Biboudis has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Address review

src/jdk.compiler/share/classes/com/sun/tools/javac/comp/TreeHasher.java line 104:

> 102:             }
> 103:         }
> 104:         if (sym instanceof PoolConstant.Dynamic dynamic) {

You could in principle add an `hashSymbol` method which does this dance - then you reuse it from both `visitIdent` and `visitSelect`

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PR Review Comment: https://git.openjdk.org/jdk/pull/21687#discussion_r1816524905