ref and out parameters on call site

[WebFreak001]

I would like to bring it up yet again! (I think this is my 3rd 
time talking about it lol)

Can we get make the call site of a ref/out function repeat the 
ref/out keyword like in C#?

Example:
void foo(double a, ref string s, out int[] x);

called with:
foo(doubleValue, ref stringValue, out intArray);

My basic idea was this:
* Force usage of ref/out on call site, otherwise cause 
deprecation for now.
* If function is called with UFCS, ref is not needed on first 
argument (before the .)


Reason:
It's currently impossible to know if a function argument mutates 
a variable or not without jumping into the definition or 
documentation. Code reviews get orders of magnitude more 
difficult to get right when calling new functions you aren't 
familiar with.

I think this would massively help readability and simplify static 
analysis and code reviews. This also has the added benefit that 
you can easily unambiguously call both ref and non-ref overloads 
using an lvalue. It also makes it possible to _require_ functions 
like template callbacks to have a ref/out parameter.

If we were to go this way, we could go all the way and even allow 
const/immutable construction out of "out" arguments:

if (generateSomething(out const something)) {
     writeln("yay, something: ", something);
}

Any ideas? Counter arguments why this shouldn't be implemented 
other than old code breakage?