Anonymous structure

[Steven Schveighoffer via Digitalmars-d-learn]

On 4/17/16 11:57 PM, Tofu Ninja wrote:
> On Monday, 18 April 2016 at 03:33:53 UTC, Adam D. Ruppe wrote:
>> The struct inside union is the main pure-language use case I know of
>> though.
>
> Actually curiously I found another potential use, applying
> attributes/UDAs to multiple members at once.
>
> enum testUDA;
> struct T{
>      @testUDA
>      immutable struct{
>          int x;
>          int y;
>          int z;
>      }
> }
>
> x,y,and z seem to all be immutable and all have the UDA testUDA. But
> even odder, it seems that "struct" in there is doing absolutely nothing.
> The same thing can be done with
>
> enum testUDA;
> struct T{
>      @testUDA
>      immutable{
>          int x;
>          int y;
>          int z;
>      }
> }
>
> So it still seems to be useless other than in the case of unions...

I wonder if it makes a difference for layout. So for example:

struct T
{
    struct
    {
       int x;
       ubyte y;
    }
    ubyte z;
}

If there is padding inserted between y and z.

-Steve