Records, Intersection type and lambda

[B. Blaser]

Probably related to:
http://mail.openjdk.java.net/pipermail/compiler-dev/2020-October/015185.html

Regards,
Bernard

On Sun, 15 Nov 2020 at 18:03, Remi Forax <forax at univ-mlv.fr> wrote:
>
> I've found this bug trying to refactor existing classes to records but it's not directly related to record, i believe.
>
> It's an issue with intersection type and lambdas,
> Weirdly, i seen to recall alreadu seeing this bug ??
>
> For me it's a compiler error, the compiler choose the first type of the intersection type (Record & Foo) instead of choosing the second, the one allowing m(Foo) to be called.
>
> regards,
> Rémi
>
> ----
>
> import java.util.List;
>
> public class RecordIntersectionTypeAndLambda {
>   interface Foo { }
>   record Bar1() implements Foo { }
>   record Bar2() implements Foo { }
>
>   static class Hello {
>     void m(Foo foo) { }
>   }
>
>   public static void main(String[] args) {
>     var list = List.of(new Bar1(), new Bar2());
>     list.forEach(new Hello()::m);
>   }
> }
>
> [forax at localhost java-fun]$ ~/jdk/jdk-16/bin/java --version
> openjdk 16-ea 2021-03-16
> OpenJDK Runtime Environment (build 16-ea+24-1553)
> OpenJDK 64-Bit Server VM (build 16-ea+24-1553, mixed mode, sharing)
>
> [forax at localhost java-fun]$ cd src/
> [forax at localhost src]$ ~/jdk/jdk-16/bin/javac RecordIntersectionTypeAndLambda.java
> [forax at localhost src]$ ~/jdk/jdk-16/bin/java RecordIntersectionTypeAndLambda
> Exception in thread "main" java.lang.BootstrapMethodError: bootstrap method initialization exception
>         at java.base/java.lang.invoke.BootstrapMethodInvoker.invoke(BootstrapMethodInvoker.java:194)
>         at java.base/java.lang.invoke.CallSite.makeSite(CallSite.java:315)
>         at java.base/java.lang.invoke.MethodHandleNatives.linkCallSiteImpl(MethodHandleNatives.java:280)
>         at java.base/java.lang.invoke.MethodHandleNatives.linkCallSite(MethodHandleNatives.java:270)
>         at RecordIntersectionTypeAndLambda.main(RecordIntersectionTypeAndLambda.java:14)
> Caused by: java.lang.invoke.LambdaConversionException: Type mismatch for lambda argument 1: class java.lang.Record is not convertible to interface RecordIntersectionTypeAndLambda$Foo
>         at java.base/java.lang.invoke.AbstractValidatingLambdaMetafactory.validateMetafactoryArgs(AbstractValidatingLambdaMetafactory.java:293)
>         at java.base/java.lang.invoke.LambdaMetafactory.metafactory(LambdaMetafactory.java:327)
>         at java.base/java.lang.invoke.BootstrapMethodInvoker.invoke(BootstrapMethodInvoker.java:127)
>         ... 4 more