Verifying the arguments of a function with ref parameters?

[pineapple via Digitalmars-d-learn]

On Thursday, 28 July 2016 at 20:28:39 UTC, jdfgjdf wrote:
> "Parameters!dgref.init" does not yield a reference. The real 
> error is not displayed. In a normal context it would be "stuff 
> is not callable with...."

What would be a better way to check whether some callable can be 
called using a parameters tuple?