The Tor Browser / file revision

 // Test yield* with iter.throw and monkeypatching.

 function* g1() { return (yield 1); }

 function* g2() { try { yield 1; } catch (e) { yield e; } }

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

 var GeneratorObjectPrototype = Object.getPrototypeOf(g1).prototype;

 var GeneratorObjectPrototype_throw = GeneratorObjectPrototype.throw;

 // An uncaught delegated throw.

 var inner = g1();

 var outer = delegate(inner);

 assertIteratorNext(outer, 1);

 assertThrowsValue(function () { outer.throw(42) }, 42);

 assertThrowsValue(function () { outer.throw(42) }, 42);

 // A caught delegated throw.

 inner = g2();

 outer = delegate(inner);

 assertIteratorNext(outer, 1);

 assertIteratorResult(outer.throw(42), 42, false);

 assertThrowsValue(function () { outer.throw(42) }, 42);

 assertThrowsValue(function () { outer.throw(42) }, 42);

 // What would be an uncaught delegated throw, but with a monkeypatched iterator.

 inner = g1();

 outer = delegate(inner);

 assertIteratorNext(outer, 1);

 inner.throw = function(e) { return e*2; };

 assertEq(84, outer.throw(42));

 assertIteratorDone(outer, undefined);

 // Monkeypatching inner.next.

 inner = g1();

 outer = delegate(inner);

 inner.next = function() { return { value: 13, done: true } };

 assertIteratorDone(outer, 13);

 // What would be a caught delegated throw, but with a monkeypunched prototype.

 inner = g2();

 outer = delegate(inner);

 assertIteratorNext(outer, 1);

 delete GeneratorObjectPrototype.throw;

 var outer_throw_42 = GeneratorObjectPrototype_throw.bind(outer, 42);

 assertThrowsValue(outer_throw_42, 42);

 assertThrowsValue(outer_throw_42, 42);

 // Monkeypunch a different throw handler.

 inner = g2();

 outer = delegate(inner);

 outer_throw_42 = GeneratorObjectPrototype_throw.bind(outer, 42);

 assertIteratorNext(outer, 1);

 GeneratorObjectPrototype.throw = function(e) { return e*2; }

 assertEq(84, outer_throw_42());

 assertEq(84, outer_throw_42());

 // This continues indefinitely.

 assertEq(84, outer_throw_42());

 assertIteratorDone(outer, undefined);

 // The same, but restoring the original pre-monkey throw.

 inner = g2();

 outer = delegate(inner);

 outer_throw_42 = GeneratorObjectPrototype_throw.bind(outer, 42);

 assertIteratorNext(outer, 1);

 assertEq(84, outer_throw_42());

 assertEq(84, outer_throw_42());

 GeneratorObjectPrototype.throw = GeneratorObjectPrototype_throw;

 assertIteratorResult(outer_throw_42(), 42, false);

 assertIteratorDone(outer, undefined);

 if (typeof reportCompare == "function")

     reportCompare(true, true);