Casting random type to random struct - is this a bug?

[Steven Schveighoffer via Digitalmars-d-learn]

On 7/15/15 11:45 AM, rumbu wrote:
> struct S { int a, b; }
> auto s = cast(S)10;
> //compiles and sets s.a to 10.
>
> It works also for any other type, if the structure contains a member of
> that type in the first position.
>
> Is this normal behaviour?

I would say this is a bug. As far as I know, it's not defined in the spec.

-Steve