RFR: 8322810: Lambda expression types can't be classes [v6]

[Maurizio Cimadamore]

On Thu, 10 Apr 2025 18:37:12 GMT, Vicente Romero <vromero at openjdk.org> wrote:

>> Currently javac is accepting code like:
>> 
>> 
>> class Test {
>>     void m() {
>>         var r = (Test & Runnable) () -> System.out.println("Hello, World!");
>>     }
>> }
>> 
>> 
>> according to: `4.9 Intersection Types` a notional interface can't be induced here as one of the components is a class different from `j.l.Object`
>> 
>> With this fix this code pattern will be rejected with a compiler error
>> 
>> TIA
>
> Vicente Romero has updated the pull request incrementally with one additional commit since the last revision:
> 
>   minor error in condition

test/langtools/tools/javac/lambda/ClassInIntersectionTypeTest.java line 32:

> 30:     static Class<? extends Annotation> myAnnoType() { return null; }
> 31:     @interface Anno {}
> 32:     Anno a = (Anno & Serializable) ()-> null; // annotations not allowed

Actually, I wonder -- the annotation should not be allowed in any position right? Not just in the first type? E.g. since an annotation is an interface, you can also have:

`Runnable & Anno1 & Anno2`

Do we detect those?

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PR Review Comment: https://git.openjdk.org/jdk/pull/24548#discussion_r2038343478