Draft JEP: Primitive Types in Patterns, instanceof, and switch (Second Preview)

[Brian Goetz]

That's probably a (well intentioned!) ECJ bug!


On 8/30/2024 3:52 PM, Stephan Herrmann wrote:
> Thanks for clarifying.
>
> FWIW ecj informs me:
>
> The type parameter T should not be bounded by the final type Integer. 
> Final types cannot be further extended
>
> :)
>
> Am 30.08.24 um 21:47 schrieb Brian Goetz:
>> I had exactly the same confusion when I read those words.  Alex set 
>> me straight.
>>
>>      <T extends Integer> int asInt(T t) { return t; }
>>
>> Here, we go from T to Integer (a widening reference conversion), then 
>> to int (an unboxing conversion).
>>
>> On 8/30/2024 3:44 PM, Stephan Herrmann wrote:
>>> The other day I stumbled upon this in the JLS changes for the first 
>>> preview (JEP 455):
>>>
>>> * a widening reference conversion followed by an unboxing conversion
>>> * a widening reference conversion followed by an unboxing 
>>> conversion, then followed by a widening primitive conversion
>>>
>>> I fail to imagine any type that can be widened to a boxing type. 
>>> What's going on here?
>>>
>>> best,
>>> Stephan
>>>
>>>
>>> Am 30.08.24 um 15:55 schrieb Angelos Bimpoudis:
>>>> Dear experts,
>>>>
>>>> A draft JEP for the second preview of primitive types in patterns, 
>>>> instanceof, and switch is now available. We propose to preview it 
>>>> for a second time with no changes relative to JDK 23. This feature 
>>>> aligns what instanceof and pattern matching mean across all types. 
>>>> This second preview, unchanged, gives ample time to amber experts 
>>>> to express their feedback.
>>>>
>>>> https://bugs.openjdk.org/browse/JDK-8335876
>>>>
>>>> Let us know of your feedback.
>>>>
>>>> Thank you,
>>>> Angelos
>>>
>>
>
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