"var" declarations shadowing properties from Window.prototype

Boris Zbarsky bzbarsky at MIT.EDU
Sun Aug 12 16:24:05 PDT 2012

On 8/12/12 5:29 PM, Brendan Eich wrote:
> Boris Zbarsky wrote:
>> Note that data in
>> http://lists.w3.org/Archives/Public/public-script-coord/2012JanMar/0033.html
>> suggests that IE also implements the erratum to 5.1 we were talking
>> about up-thread.  Oh what a tangled web we weave.
> Yes, current thinking is that we should take the erratum that major JS
> engines already fixed, and include it in ES6. But this means we must do
> something different in WebIDL, probably make own global properties for
> window-implements-interface-inherited attributes and even operations.
> And then (for strict mode) be careful about get-only accessors. This
> reminds me of [Replaceable], which was for non-writable but configurable
> data properties that var and function must be able to replace. It's kind
> of the opposite and only for accessors:
> var-captures-own-accessor-via-detection, or some such.
> Just recapping, tell me if I'm missing something.

The above sounds like a reasonable summary to me.  Certainly hits all 
the high points of the discussion, with the addition that the GSP as 
currently specced depends on the erratum sticking around.


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