SumType!(A,B) != SumType!(B,A) - a bug?

[Paul Backus]

On Tuesday, 26 December 2023 at 19:30:14 UTC, Andrey Zherikov 
wrote:
> On Tuesday, 26 December 2023 at 19:19:08 UTC, Paul Backus wrote:
>> I think this is probably a compiler bug, but it's hard to tell 
>> without a reduced example.
>
> Output from dustmite:
>
> ```d
> void main()
> {
>     import std;
>     struct B { int[] i; }
>
>     immutable s2 = SumType!B(B.init);    // compilation error
> }
> ```

Needs to include `std.sumtype` in the reduction to be useful. I 
recommend copying `sumtype.d` from Phobos to a new directory to 
create a self-contained example.