Null references (oh no, not again!)

[BCS]

Hello Christopher,

> BCS wrote:
> 
>> Your right, but if you switch to a class and factory with no public
>> constructor, you can make it work. The problem of perf going down the
>> drain is avoidable if you can (in that mode) enforce compile time
>> checking of most cases and requiter calls to do run time checks for
>> the rest. If the template works right, than flipping back to
>> alias/typedef mode leaves the run time checks and leave the unchecked
>> code as correct while doing away with the perf problems.
>> 
> If you use a class, you're begging the question. It's just that you'll
> have a null NotNull!(T) rather than a null T.
> 
> Granted, you can use opAssign(T) instead, but you still need
> contracts.
> 

That won't be an issue because it's a run time concern and I am proposing 
that the class based version never even run. In fact it could even not be 
runable. All it does is enforce usage patterns that do work correctly with 
a different set of definitions.