20:52
<ljharb>

can anyone come up with an x and y (without using Proxy)where Object.prototype.isPrototypeOf.call(x, y) and Object.prototype.isPrototypeOf.call(y, x) are both true, and x !== y?

because i've got one in IE 8 that defies my understanding

22:06
<shu>
like, is it possible to legitimately construct a cycle with [[Prototype]] without "spoofing" the answer with proxies?
22:06
<shu>
i... hope not?
22:09
<bakkot>
OrdinarySetPrototypeOf checks for cycles so you can't do it as a user without exotics https://tc39.es/ecma262/multipage/ordinary-and-exotic-objects-behaviours.html#sec-ordinarysetprototypeof
22:09
<bakkot>
but nothing strictly forbids a host from providing a pair of ordinary objects where each is the other's [[Prototype]]
22:10
<shu>
i feel like things would just iloop
22:11
<shu>
afaik v8 or other engines don't implement cycle checking everywhere we do a prototype walk, even as a debug assert