src/third_party/mozjs-45/js/src/jit-test/tests/for-of/semantics-06.js

// Deleting the .next method makes for-of stop working on arrays.

load(libdir + "asserts.js");
load(libdir + "iteration.js");

var iterProto = Object.getPrototypeOf([][Symbol.iterator]());
delete iterProto.next;
assertThrowsInstanceOf(function () { for (var v of []) ; }, TypeError);