AliasSeq in UDA

[Basile B.]

On Sunday, 10 March 2019 at 13:20:12 UTC, Sebastiaan Koppe wrote:
> The compiler complains about `cannot form tuple of tuples` 
> whenever I try to put an AliasSeq in a UDA and try to use it.
>
> You would expect the compiler to expand it. Is this a bug?
>
> ---
>
> import std.meta;
>
> enum A; enum B;
>
> @AliasSeq!(A,B) // <-- Error: cannot form tuple of tuples
> struct Foo {}
>
> pragma(msg, __traits(getAttributes, Foo)); // <- must be 
> present (error happens only when queried)
>
> void main() {}
>
> ---
>
> link to run.dlang.io: 
> https://run.dlang.io/gist/cd5cd94d8ce5327e8a7d5ad77f1d15b8

It looks like a bug, a "reject-valid" one.
Try the same code with

     enum A = 0;

and it work, despite of B being still opaque. The problem may be 
related to the fact the enum A in the orginal code is opaque and 
has not type.

I've seen a related issue lately.