How to port C++ std::is_reference<T> to D ?

[Q. Schroll]

On Wednesday, 6 May 2020 at 09:07:22 UTC, wjoe wrote:
> Hello,
>
> I'm choking on a piece of C++ I have no idea about how to 
> translate to D.
>
> std::is_reference<T>

In general, you can't. In D, `ref` is not part of the type, it's 
a "storage class", and as such it is a property that a function 
parameter can have alongside its type. I.e. in C++, it makes 
sense to ask: "Is that parameter's type a reference type?" But in 
D it doesn't; you could ask: "Is the parameter given by 
reference?" ("Does the parameter have the storage class `ref` [or 
`out` to be complete]?")

C++'s decision to make references part of the type has some 
advantages, but D didn't do it because of many disadvantages.