'Auto can only be used for template function arguments' what?

[Mehrdad]

On Wednesday, 27 June 2012 at 04:26:08 UTC, Jonathan M Davis 
wrote:
> And how would that work? auto ref duplicates the function. If 
> you pass it an lvalue, then it generates a ref version.


Two solutions:

- Turn 'auto ref' into 'ref', but simply have the compiler 
generate a copy for the caller if he wants to pass by value?

- Treat it as though it were a templated parameter. Why does it 
make any difference here?