RFR: 8263358: Update java.lang to use instanceof pattern variable [v5]

[Rémi Forax]

On Mon, 15 Mar 2021 11:01:48 GMT, Pavel Rappo <prappo at openjdk.org> wrote:

>> The problem is that `desc` is a raw type and raw types doesn't play well with the rest of the language (in particular with inference).
>> 
>> I think it's a bug in javac, it should not even raise a warning but an error.
>> But the spec is not fully clear.
>> 
>> The spec says that the narrow conversion should not be unchecked
>> https://docs.oracle.com/javase/specs/jls/se15/preview/specs/patterns-instanceof-jls.html#jls-14.30.2
>> it depends if you consider the raw conversion as unchecked or not.
>
>> I think it's a bug in javac, it should not even raise a warning but an error.
>> But the spec is not fully clear.
> 
> If you think that it's a bug, consider providing feedback to authors of JEP 394:
> 
>> Other refinements may be incorporated based on further feedback.
> 
> I find it hard to believe that authors didn't consider generic use case (even though JEP 394 doesn't have examples of that).

We have considered generics, that why parameterized generics with another type arguments are forbidden, but i think we have forgotten raw types.

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PR: https://git.openjdk.java.net/jdk/pull/2913