I am just going to put this out there, but I will vote against any RFC which provides access to userland to overload == and <=> until the base semantics of PHP comparisons are fixed and the necessary engine prerequisite work is done.
I am working on such an RFC, as I frankly do not trust people to think stuff through and handle things like polymorphic comparisons. Also, introducing some new kind of weird operator is just... bad. Best regards, George P. Banyard