Bug in switch around Enums?

[Jonathan Gibbons]

Hey guys,

Just a gentle reminder this alias is for developers working on the  
compiler, and is not intended to be a general forum for discussing  
the shortcomings of and enhancements to the language itself.

-- Jon 

On Sep 29, 2007, at 11:42 AM, Brian Slesinsky wrote:

> Sure, support for constant expressions that return an enum seems  
> like a win.
>
> It would also solve a different gotcha.  This doesn't work:
>
>   void doSwitch(MyEnum x) {
>     switch (x) {
>       case MyEnum.FOO:
>         // do something
>     }
>   }
>
> This was the first thing I tried (by experiment, rather than reading
> the spec) and for a short time I was under the impression that enums
> don't work with switch statements.  The same thing happened to one
> other person I know.  Even if the spec isn't changed, clear error
> messages help.  (Although I believe it was IntelliJ that confused me,
> not javac.)
>
> - Brian
>
> On 9/29/07, Tom Ball <Tom.Ball at sun.com> wrote:
>> Okay, it's not a bug since the spec says its not.  It is still an
>> unnecessary syntactic inconsistency between constants and enums,
>> however, and inconsistencies like this making the language a little
>> harder to learn (yet another rule to remember).  This can't be  
>> changed
>> in the compiler until the spec is, but perhaps there is a related
>> pending JSR which can add it as an update.
>>
>> Tom
>>
>> Matthias Ernst wrote:
>>> Ted,
>>>
>>> according to the JLS it's not a bug.
>>>
>>> Switch labels can either be constant expressions or enum  
>>> identifiers:
>>>
>>> http://java.sun.com/docs/books/jls/third_edition/html/ 
>>> statements.html#14.11
>>> SwitchLabel:
>>>        case ConstantExpression :
>>>        case EnumConstantName :
>>>        default :
>>>
>>> and constant expression is only defined for primitives and String:
>>> http://java.sun.com/docs/books/jls/third_edition/html/ 
>>> expressions.html#15.28
>>>
>>> So (STAGGER) is neither a constant expression nor an enum  
>>> constant name.
>>>
>>> Feel free to call me type 1
>>> (http://diveintomark.org/archives/2004/08/16/specs) :-)
>>>
>>> Matthias
>>
>>