michael@0: // Deleting the .next method of an iterator in the middle of a for-of loop
michael@0: // causes a TypeError at the next iteration.
michael@0: 
michael@0: load(libdir + "asserts.js");
michael@0: load(libdir + "iteration.js");
michael@0: 
michael@0: var iterProto = Object.getPrototypeOf([][std_iterator]());
michael@0: var s = '';
michael@0: assertThrowsInstanceOf(function () {
michael@0:     for (var v of ['duck', 'duck', 'duck', 'goose', 'FAIL']) {
michael@0:         s += v;
michael@0:         if (v === 'goose')
michael@0:             delete iterProto.next;
michael@0:         s += '.';
michael@0:     }
michael@0: }, TypeError);
michael@0: assertEq(s, 'duck.duck.duck.goose.');