RFR JDK-8215470: Bad EnclosingMethod attribute on classes declared in lambdas

Maurizio Cimadamore maurizio.cimadamore at oracle.com
Fri Jan 18 14:43:46 UTC 2019

i think when you say "javac is not in sync with the spec" that's a bit 
harsh. There are two possible enclosing methods - the synthetic lambda 
and the 'real' one. There's nothing in the spec suggesting that the 
enclosingMethod attribute should point one way or another.

Also not 100% on 'minimal' as compatibility risk - while it's true that 
there's no official commitment one way or another, this change will 
result in behavioral changes with core reflection. Also, I don't think I 
can think of another case where EnclosingMethod is set to something so 
that a real classfile method is 'skipped' over.


On 18/01/2019 13:32, Vicente Romero wrote:
> Hi,
> I also need a review on the CSR: 
> https://bugs.openjdk.java.net/browse/JDK-8217272
> Thanks,
> Vicente
> On 1/17/19 1:50 PM, Vicente Romero wrote:
>> On 1/17/19 1:31 PM, Maurizio Cimadamore wrote:
>>> Looks good - all tests clear despite the removals?
>> yes on my local, anyway I will do a test on all platforms before pushing
>>> Maurizio
>> Thanks,
>> Vicente
>>> On 17/01/2019 02:15, Vicente Romero wrote:
>>>> Hi Maurizio,
>>>> Thanks for your comments. What about [1]?
>>>> Vicente
>>>> [1] 
>>>> http://cr.openjdk.java.net/~vromero/8215470/webrev.01/jdk.dev.patch
>>>> On 1/16/19 4:05 PM, Maurizio Cimadamore wrote:
>>>>> The patch looks good - but I have some questions; sometime ago 
>>>>> some logic was added to LambdaToMethod to handle type variables - 
>>>>> see LambdaSymbolKind.TypeVar and related code.
>>>>> I have the vague feeling that this code was added precisely for 
>>>>> this reason: to fixup issues related to missing type-variable in 
>>>>> the enclosing method. If now you point to the correct method (as 
>>>>> per source code), wouldn't this code be redundant? Doing some 
>>>>> analysis on the code (hg annotate) I was able to get to this bug:
>>>>> https://bugs.openjdk.java.net/browse/JDK-8005653
>>>>> Looking at the synopsis, I see an inner class with an enclosing 
>>>>> method - and a dandling type variable reference... I think this is 
>>>>> overlapping with the issue you are trying to fix.
>>>>> Also, I think it would be nice to have a test which uses 
>>>>> reflection to poke at the type variables, and checks that the 
>>>>> runtime values of the type-variables in the local class are indeed 
>>>>> the same as the ones in the enclosing method.
>>>>> Maurizio
>>>>> On 16/01/2019 19:55, Vicente Romero wrote:
>>>>>> Please review fix for [1] at [2]. The fix is about pointing the 
>>>>>> enclosing method attribute of inner classes inside a lambda; to 
>>>>>> the original method in which the inner class was declared. 
>>>>>> Currently javac is pointing it to the synthetic method that 
>>>>>> contains the lambda implementation. Please review the CSR too,
>>>>>> Thanks,
>>>>>> Vicente
>>>>>> [1] https://bugs.openjdk.java.net/browse/JDK-8215470
>>>>>> [2] http://cr.openjdk.java.net/~vromero/8215470/webrev.00/
>>>>>> [3] https://bugs.openjdk.java.net/browse/JDK-8217272

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