compile time 'address'

[Dominic Jones]

On Thursday, 29 November 2018 at 21:00:57 UTC, Stanislav Blinov 
wrote:

>> There's no way to accept a pointer that can't be used, just 
>> the value of the pointer checked.
>
> Yeah, but this one seems a bit deliberate. The asserts hold, 
> but you can't e.g.
>
> enum diff = &c0 - &c1; // 'c0' can't be used at compile time

This is the same situation as C++; the addresses can only be 
compared (with == or !=). Any attempt to capture their values 
first will cause a compilation failure, i.e. attempting:

   // "error: '& t' is not a constant expression", etc
   auto constexpr ta = &t;
   auto constexpr ua = &u;
   return ta == ua;