Querying parameter passing semantics for `auto ref const` variables

[Nordlöw via Digitalmars-d-learn]

Is there a way to query at compile-time whether a call to

     f(T)(auto ref const T x)

passed the variable `x` from a l-value or r-value?

A call to `isRef!T` inside the function `f` is always `false` for 
`l-value` and `r-value` passing.

I need this to detect automatic delayed evaluation of 
sub-expressions in my GNU MP wrapper at

https://github.com/nordlow/gmp-d