What's the correct opEquals signature for structs?

[Jonathan M Davis]

On Tuesday, March 13, 2012 19:28:26 Johannes Pfau wrote:
> My std.uuid module doesn't compile with the latest dmd. I guess it's
> because of a wrong opEquals signature, this is what I have now:
> 
> ----------
> @safe pure nothrow bool opEquals(ref const UUID s) const
> {
> return s.data == this.data;
> }
> ----------
> 
> and
> 
> ----------
> assert(UUID("00000000-0000-0000-0000-000000000000") == nilUUID);
> ----------
> The complete code is here:
> https://github.com/jpf91/phobos/blob/std.uuid/std/uuid.d
> 
> What's the best way to solve this issue?

At present, I believe that the correct solution is to have two opEquals. 
That's what Kenji did when he fixed the various structs in Phobos recently. For 
instane, std.datetime.SysTime's opEquals now looks like this:

bool opEquals(const SysTime rhs) const pure nothrow
{
 return opEquals(rhs);
}

/// ditto
bool opEquals(const ref SysTime rhs) const pure nothrow
{
 return _stdTime == rhs._stdTime;
}

Ideally, auto ref would work, but it currently only works with templates. I 
believe that that's supposed to be changed, but it hasn't been yet.

- Jonathan M Davis