Bug in switch around Enums?

[Brian Slesinsky]

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
>
>