Problem with opBinary

[Jonathan M Davis]

On Wednesday, November 14, 2018 2:54:27 AM MST realhet via Digitalmars-d-
learn wrote:
> Hi,
>
> Just a little weird thing I noticed and don't know why it is:
>
> I have a FilePath struct and I wanted to make it work with the
> "~" operator and an additional string.
>
> So I've created a global funct:
>
>    FilePath opBinary(string op:"~")(FilePath p1, string p2){
>      return FilePath(p1, p2);
>    }
>
> The problem is that this funct is only callable with the
> following code:
>
>    auto vlcPath = programFilesPath.opBinary!"~"(`VideoLAN\VLC`);
>
> And it is not callable using the ~ operator directly. It says
> unable to call with types  FilePath and string
>
> When I rewrite the opBinary funct as a member of the FilePath
> struct, everything is working fine. The problem is only happening
> when opBinary is a global funct. (I'm using LDC Win64)
>
> Is it a bug or is there an explanation to this?

In D, all overloaded operators must be member functions.

- Jonathan M Davis