RFR: 8325805: Compiler Implementation for Flexible Constructor Bodies (Second Preview) [v5]

[Jan Lahoda]

On Tue, 30 Apr 2024 03:01:36 GMT, Archie Cobbs <acobbs at openjdk.org> wrote:

>> This patch changes the compiler to allow constructors to make assignments to fields prior to the `super()` invocation, i.e., in the pre-construction context.  This is part of the work associated with [JDK-8325803 - Flexible Constructor Bodies (Second Preview)](https://bugs.openjdk.org/browse/JDK-8325803).
>> 
>> This patch is based the relevant bits from @vicente-romero-oracle's commit [1b99b5cf](https://github.com/openjdk/valhalla/commit/1b99b5cfd9a5d484b9e7bdfc284daad9ad6535bf) to the valhalla repo.
>
> Archie Cobbs has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 20 commits:
> 
>  - Allow declaring and instantiating local classes prior to super().
>  - Merge branch 'master' into JDK-8325805
>  - Merge branch 'master' into JDK-8325805
>  - Disallow assignments to fields with initializers in constructor prologues.
>  - Merge branch 'master' into JDK-8325805
>  - Merge branch 'master' into JDK-8325805
>  - Fix cut & paste of bug ID and summary.
>  - Avoid possible unwanted side effects from method Symbol.flags().
>  - Add a few more test cases.
>  - Fix bug where early assignments in lambda's were being allowed.
>  - ... and 10 more: https://git.openjdk.org/jdk/compare/9b423a85...7e6a6a0d

src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Resolve.java line 3778:

> 3776:                     if (staticOnly)
> 3777:                         sym = new StaticError(sym);
> 3778:                     else if (env1.info.ctorPrologue && sym.kind == VAR && !isAllowedInPrologue(env1, (VarSymbol)sym))

Question: why `sym.kind == VAR`? Can `sym` be something else then a variable here (given `name` can only be `this` or `super`, unless I am mistaken)?

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PR Review Comment: https://git.openjdk.org/jdk/pull/18088#discussion_r1593629172