ex. class Node { } SyntaxError: Can't create duplicate variable that shadows a global property: 'Node' but you can write var Node = class Node { } this works fine in Chrome and Firefox 45.
This is still broken, I think something is wrong in your lexical scoping.
I just checked today's nightly: r202375 and it still happens.
In general, it seems that JSC refuses to create lexical bindings that shadow configurable properties on the global object, contra the spec (see https://tc39.github.io/ecma262/#sec-hasrestrictedglobalproperty). Here's a DOM-less repro: >>> let Array = 5 Exception: SyntaxError: Can't create duplicate variable that shadows a global property: 'Array' or one with a self-created property: >>> Object.defineProperty(this, 'foo', {value: 5, configurable: true, writable: true}) [object global] >>> let foo = 10 Exception: SyntaxError: Can't create duplicate variable that shadows a global property: 'Foo'
*** This bug has been marked as a duplicate of bug 148763 ***