Must built-in prototypes also be valid instances? (Was: Why DataView.prototype object's [[Class]] is "Object"?)

David Bruant bruant.d at
Tue Oct 2 01:33:35 PDT 2012

2012/10/2 Mark S. Miller <erights at>

> On Mon, Oct 1, 2012 at 9:02 PM, Brendan Eich <brendan at> wrote:
>> Words on paper still carry force but they do not necessarily have prompt
>> effects, or any effects. It depends on the people reading them and
>> implementing, and trying to follow the rules. Those people are much more
>> likely to audit their (closed, per release, typically) set of host objects
>> and fix any spoofers.
> I think we're agreeing but for one thing. The force of a normative
> specification is that violations can be added to test262, so that they
> stand out like a sore thumb, putting pressure on the violator to fix it. We
> already did this successfully with one host object violation.

But test262 can't really get out of its way and test host objects since
they are implementation-dependent. I actually reported a couple of
erroneous test cases that were relying on DOM features to work.
We need WebIDL tests. For that matter, I'll try to attend testthewebforward
in Paris at the end of the month [1] and start working on that if I do
attend. I estimate the amount of work to get decent WebIDL (ECMAScript
binding of browser APIs) coverage as "ridiculously huge".


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