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

[Stephan Herrmann]

Why should it be a bug to inform the user about bad style?

Note, that users are free to chose the severity of this problem as one of Error, 
Warning, Info or Ignore.


Am 30.08.24 um 21:55 schrieb 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
>>>>
>>>
>>
>