Project Elvis

[Ola Fosheim Grøstad]

On Sunday, 29 October 2017 at 16:29:57 UTC, Jonathan M Davis 
wrote:
> valid using ?:, I would think that you'd want to be doing the 
> same check with stuff like if statements anyway. So, it sounds 
> to me like overloading opCast!bool would work just fine.

If you try to do:

some_float ?: 0.0

then it will do nothing as cast(bool)std.math.NaN(0) => true


But that is just one of many possible examples. The elvis 
operator as proposed does not match on nullity / invalid state.