Why can't we make reference variables?

[Tommi]

On Wednesday, 29 August 2012 at 03:17:39 UTC, Era Scarecrow wrote:
>  To add on to this a little.. If you can only ref by calling, 
> you ensure the variable is alive/valid when you are calling it 
> regardless if it's stack or heap or global (But can't ensure it 
> once the scope ends). Making a reference as a variable modifier 
> won't work, but using a pointer you're already going lower 
> level and it's all up to you the programmer to make sure it's 
> right.
>
>  I think that's right; Otherwise ref wouldn't be allowed in 
> @safe code (at all).

But couldn't the compiler disallow all unsafe ref use in @safe 
code, and allow all use of ref in @system and @trusted code?