Why can't we make reference variables?

[Tommi]

On Wednesday, 29 August 2012 at 02:57:27 UTC, Era Scarecrow wrote:
>  Assuming 'ref' works:
>
>  struct S {
>    ref int r;
>  }
>
>  //ref local variable/stack, Ticking timebomb
>  //compiler may refuse
>  void useRef(ref S input, int r) {
>    input.r = r;
>  }

I think we might be talking about somewhat different things. What 
I mean by reference variable is what the term means in C++. From 
wikipedia: http://en.wikipedia.org/wiki/Reference_%28C%2B%2B%29

C++ references differ from pointers in several essential ways:

* It is not possible to refer directly to a reference object 
after it is defined; any occurrence of its name refers directly 
to the object it references.

* Once a reference is created, it cannot be later made to 
reference another object; it cannot be reseated. This is often 
done with pointers.

*References cannot be null, whereas pointers can; every reference 
refers to some object, although it may or may not be valid. Note 
that for this reason, containers of references are not allowed.

* References cannot be uninitialized. Because it is impossible to 
reinitialize a reference, they must be initialized as soon as 
they are created. In particular, local and global variables must 
be initialized where they are defined, and references which are 
data members of class instances must be initialized in the 
initializer list of the class's constructor. For example:
int& k; // compiler will complain: error: `k' declared as 
reference but not initialized