RFR: 8367530: The exhaustiveness errors could be improved [v8]

[Maurizio Cimadamore]

On Fri, 14 Nov 2025 13:31:01 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

>> Jan Lahoda has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Fixing trailing whitespaces.
>
> src/jdk.compiler/share/classes/com/sun/tools/javac/comp/ExhaustivenessComputer.java line 161:
> 
>> 159:                                 return enum2Constants.get(enumType).stream().map(c -> enumType.toString() + "." + c.name);
>> 160:                             } else {
>> 161:                                 return Stream.of(pd.toString());
> 
> As discussed offline, eager string generation will render the diagnostic arguments completely opaque to the formatter. This would mean that no `where` clauses will be generated, and unambiguous qualifiers will not be omitted.

Also, don't forget `JCDiagnostic.MultilineDiagnostic`, which we use in overloads to render repetitive fragments in tabular format.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27256#discussion_r2527692180