C to D: please help translate this weird macro

[Nick Treleaven]

On Thursday, 21 September 2023 at 16:28:25 UTC, Nick Treleaven 
wrote:
>     return cast(T*)(cast(void*)(cast(char*)ptr -
>         __traits(getMember, T, member).offsetof)));

There's a trailing `)` that needs removing. Also pretty sure it 
can be simplified to:

     return cast(T*)(cast(char*)ptr -
         __traits(getMember, T, member).offsetof);