<!DOCTYPE html> <meta charset="utf-8"> <title>All attributes accessors are unique function objects</title> <link rel="help" href="https://webidl.spec.whatwg.org/#idl-interface-mixins"> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <script> "use strict"; test(() => { const seenPrototypes = new WeakSet([Function.prototype]); const seenFunctions = new WeakMap(); for (const windowKey of Object.getOwnPropertyNames(window)) { const windowValue = window[windowKey]; if (typeof windowValue !== "function") continue; const {prototype} = windowValue; if (!prototype || seenPrototypes.has(prototype)) continue; seenPrototypes.add(prototype); for (const key of Object.getOwnPropertyNames(prototype)) { const assert_not_seen = (fn, field) => { const fnInfo = `${windowKey}.${key}.${field}`; assert_equals(seenFunctions.get(fn), undefined, fnInfo); seenFunctions.set(fn, fnInfo); }; const desc = Object.getOwnPropertyDescriptor(prototype, key); if (desc.get) assert_not_seen(desc.get, "[[Get]]"); if (desc.set) assert_not_seen(desc.set, "[[Set]]"); } } }, "For attributes, each copy of the accessor property has distinct built-in function objects for its getters and setters."); </script>