Querying parameter passing semantics for `auto ref const` variables

[kinke via Digitalmars-d-learn]

On Sunday, 15 January 2017 at 14:33:25 UTC, Nordlöw wrote:
> A call to `isRef!T` inside the function `f` is always `false` 
> for `l-value` and `r-value` passing.

According to 
https://dlang.org/spec/template.html#auto-ref-parameters, it 
should be `__traits(isRef, x)`.