[jdk17] RFR: 8270006: Switches with 'case null:' should be exhaustive

[Jan Lahoda]

On Wed, 7 Jul 2021 12:37:46 GMT, Rémi Forax <forax at openjdk.org> wrote:

>> Code like:
>> 
>>     void exhaustiveAndNull(String s) {
>>         switch (s) {
>>             case null: break;
>>         }
>>     }
>> 
>> 
>> should be rejected, because the switch is no exhaustive, but it is a "new" switch. (Note that this not a problem for switch expressions, which always have to be exhaustive.)
>
> test/langtools/tools/javac/patterns/SwitchErrors.java line 192:
> 
>> 190:             case null: break;
>> 191:         }
>> 192:     }
> 
> The other possible new syntax is "case default", but there is no error because it's exhaustive.
> 
> 
> void exhaustiveCaseDefaultNoError(String s) {
>         switch (s) {
>             case default: break;
>         }
>     }

Correct, there are tests that verify (at least as a side-effect) that `case default` is total in `test/langtools/tools/javac/patterns/CaseDefault.java`.

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PR: https://git.openjdk.java.net/jdk17/pull/224