Expression switch exception naming

[Brian Goetz]

I'm not talking about recovering.  This is purely taxonomy; this sort of 
mismatch does not (IMO) rise to the level of Error.

On 3/30/2018 2:42 PM, Remi Forax wrote:
> You still have not explain why you want to recover from one of these exception knowning that it's simpler to add a default if you want to take care of an unknown enum constant.
>
> Rémi
>
> ----- Mail original -----
>> De: "Brian Goetz" <brian.goetz at oracle.com>
>> À: "Kevin Bourrillion" <kevinb at google.com>
>> Cc: "amber-spec-experts" <amber-spec-experts at openjdk.java.net>
>> Envoyé: Vendredi 30 Mars 2018 20:39:30
>> Objet: Re: Expression switch exception naming
>>> All right, I've been focusing too much on the hierarchy, but the
>>> leaf-level name is more important than that (and the message text
>>> further still, and since I assume we'll do a fine job of that, I can
>>> probably relax a little). To answer your question, sure, the "ICC" is
>>> a pretty decent signal. Have we discussed Cyrill's point on -observers
>>> that we should create more specific exception types, such as
>>> UnrecognizedEnumConstantE{rror,xception}?
>> Yes.  What I'd been proposing was something like:
>>
>> class IncompatibleClassChangeException <: Exception
>> or
>> classUnexpectedClassChangeException <: Exception
>>
>> and then
>>
>> UnexpectedEnumConstantException <: {I,U}CCE
>> UnexpectedSealedTypeException <: {I,U}CCE
>>
>>
>>> Okay, that is a sane approach, but I think it leaves too much of the
>>> value on the floor. I often benefit from having my exhaustiveness
>>> validated and being able to find out at compile time if things change
>>> in the future.
>> To be clear, I was describing:
>>   - We'd always do exhaustiveness checking for expression switches
>>   - A default / total pattern always implies exhaustive
>>   - We'd additionally consider an expression switch to be exhaustive if
>> all known enums are present _and_ the enum type is in the same module as
>> the switch
>>
>> But that's probably too fussy.