On Wed, Aug 26, 2015 at 2:55 PM, Kevin Gibbons <[email protected]> wrote:
> See the following test262 test: > https://github.com/tc39/test262/blob/master/test/language/expressions/assignment/S11.13.1_A5_T5.js > (and related tests with update / compound assignment). > > In short, it is possible to have a Reference to a global variable which > has been deleted. Normally, bare assignments to undeclared variables in > strict mode cause ReferenceErrors. However, calling PutValue on a reference > to a global variable which has been deleted since the reference was created > does not throw a ReferenceError in strict mode, even though, *at the time > of writing*, that variable does not exist. > > As far as I can tell, this is true in ES5 as well as ES6, but none of {V8, > SpiderMonkey, JavaScriptCore, Nashorn} get it right. This is consistent and > makes sense, but is it intentional? > Hmmm, interesting. It was not the intention of the strict mode design to allow this to slip by without a thrown error. If we had explicitly considered this issue during the early strict mode design, we definitely would have made this a thrown error of some sort. ReferenceError sounds good to me, but I can't say that we would not have decided on TypeError. Either seems plausible enough. I agree that the silent failure implied by the current spec is buggy. Please file a bug against the ES6 spec. We should correct this at least in the errata. Thanks for raising this! And thanks to André Bargull for writing that test case! I wish I was aware of it earlier. -- Cheers, --MarkM
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