opCmp / opEquals do not actually support partial orders

[Jonathan M Davis]

On Tuesday, July 17, 2018 21:18:12 John Colvin via Digitalmars-d wrote:
> Just do what std.typecons.Proxy does and return float.nan for the
> incomparable case.

Since when is that legal? I thought that it was required for opCmp to return
int. Certainly, the spec implies that it has to be int. The fact that the
compiler allows it seems like a bug, though if Phobos is doing it, it
wouldn't surprise me if Walter would choose to update the spec rather than
fixing the compiler.

- Jonathan M Davis