Suggestion: "fix" assert(obj)

[Xinok]

Kristian Kilpi wrote:
> So, one should usually write instead:
> 
>   assert(obj !is null);
>   assert(obj);

Until we do get a fix for this problem, wouldn't it be easiest to put 
this check in the invariant itself?

invariant{
	assert(this !is null);
}