Null references (oh no, not again!)

[Walter Bright]

bearophile wrote:
> Walter Bright:
>> Joel C. Salomon:
>>> To avoid this class of bug, you need a simple way to declare what
>>> the acceptable values for a variable are.
>> Languages have had this capability, but it never caught on. People
>> found it just too tedious.
> 
> What? We use ranges of integers in Delphi at work today :-) I have
> even proposed something similar for D twice in the past. (But to be
> precise, I often don't use ranged integral numbers for the purpose
> discussed here).

I didn't mean nobody liked them or used them. I mean they have not 
caught on, despite having been around for 3 decades at least.