is there a way to use sumtype in `switch/case` (with multiple statements)? or how can I get the `tag` and `storage`?

[mw]

On Saturday, 7 October 2023 at 19:30:23 UTC, mw wrote:
> On Saturday, 7 October 2023 at 19:25:51 UTC, mw wrote:
>> Or how can I get the `tag` and `storage` myself?
>>
>> https://github.com/dlang/phobos/blob/a3f22129dd2a134338ca02b79ff0de242d7f016e/std/sumtype.d#L310
>>
>
> If I add this line to the above func `isF`:
>
> ```
>   writeln(t.tag);
> ```
>
> it won't compile:
>
> sum_type.d(79): Error: no property `tag` for `t` of type 
> `std.sumtype.SumType!(Fahrenheit, Celsius, Kelvin)`

Shouldn't the compiler error message be: t.tag is private? rather 
than "no property `tag` for `t`"?

The tag is stored there, why the programmer cannot inspect it, 
and get the payload?