RFR: JDK-8267041: javac crash when creating lambda with capture inside a switch expression

[Maurizio Cimadamore]

On Thu, 13 May 2021 15:05:58 GMT, Vicente Romero <vromero at openjdk.org> wrote:

>> Variables declared inside switch expressions used as initializers to fields have the field as their owner. We need to make sure they are captured by `LambdaToMethod` - there were a few places where the checks were missing, leading to a crash later during code generation.
>
> src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java line 1356:
> 
>> 1354:             if (context() != null && lambdaIdentSymbolFilter(tree.sym)) {
>> 1355:                 if (tree.sym.kind == VAR &&
>> 1356:                         (tree.sym.owner.kind == MTH || tree.sym.owner.kind == VAR) &&
> 
> just curious: why wasn't this code stressed before? I mean it should be possible to stress it without switch expressions right?

Uhm - don't we always try to create a block/synthetic method symbol for owner of variables declared inside initializers? I think the case where this happens is lambda expression parameters - which can occur in field initializers. The parameters should point to some "init block" as their owner, not the var. Shouldn't switch behave the same? (having variables being owner of other variables breaks invariants in the code).

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PR: https://git.openjdk.java.net/jdk/pull/4012