The Tor Browser / file revision

 // Errors accessing next, done, or value don't cause an exception to be

 // thrown into the iterator of a yield*.

 function* g(n) { for (var i=0; i<n; i++) yield i; }

 function* delegate(iter) { return yield* iter; }

 var log = "", inner, outer;

 // That var is poisoooooon, p-poison poison...

 var Poison = new Error;

 function log_calls(method) {

     return function () {

         log += "x"

         return method.call(this);

     }

 }

 function poison(receiver, prop) {

     Object.defineProperty(receiver, prop, { get: function () { throw Poison } });

 }

 // Poison inner.next.

 inner = g(10);

 outer = delegate(inner);

 inner.throw = log_calls(inner.throw);

 poison(inner, 'next')

 assertThrowsValue(outer.next.bind(outer), Poison);

 assertEq(log, "");

 // Poison result value from inner.

 inner = g(10);

 outer = delegate(inner);

 inner.next = function () { return { done: true, get value() { throw Poison} } };

 inner.throw = log_calls(inner.throw);

 assertThrowsValue(outer.next.bind(outer), Poison);

 assertEq(log, "");

 // Poison result done from inner.

 inner = g(10);

 outer = delegate(inner);

 inner.next = function () { return { get done() { throw Poison }, value: 42 } };

 inner.throw = log_calls(inner.throw);

 assertThrowsValue(outer.next.bind(outer), Poison);

 assertEq(log, "");

 // mischief managed.

 if (typeof reportCompare == "function")

     reportCompare(true, true);