> On Apr 9, 2018, at 1:14 PM, Brian Goetz <brian.go...@oracle.com> wrote:
> A form of fallthrough that I think may be more common in expression switches 
> is when something wants to fall _into_ the default:
>     int x = switch (y) {
>         case "Foo" -> 1;
>         case "Bar" -> 2;
>         case null:
>         default:
>             // handle exceptional case here
>     }
> Because `default` is not a pattern, we can't say:
>     case null, default:
> here.  (Well, we could make it one.)  Though we could carve out an exception 
> for such "trivial" fallthrough.

As a matter of terminology, I think it would be helpful for us to not call this 
fallthrough at all. It creates a lot of confusion when somebody is making an 
assertion about fallthrough, and it's unclear whether this kind of thing is 
being included or not.

JLS is a good guide: grammatically, the body of a switch statement is a 
sequence of SwitchBlocks, each of which has a sequence of SwitchLabels followed 
by some BlockStatements.


JLS doesn't formally define the concept of "fallthrough" but I suggest we use 
it to describe the situation in which control flows from one SwitchBlock to 

What you've illustrated is instead a "switch case with multiple 
labels"—something deserving scrutiny on its own, but really a different sort of 
problem than fallthrough.


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