Cast a struct to void*

[anonymous via Digitalmars-d-learn]

On Friday, 9 January 2015 at 18:25:42 UTC, John Colvin wrote:
> struct S
> {
>     void* p;
> }
>
> void main()
> {
>     S s;
>     auto a = cast(void*)s; //Error: e2ir: cannot cast s of type 
> S to type void*
> }
>
> Is there are a good reason for this being disallowed?

You'd expect `cast(void*)s == s.p`? That doesn't work for any 
type of p. You can do it with a slightly fancier (and more 
dangerous) cast: `*cast(void**)&s`.