Throwing errors on mutating immutable bindings

Brendan Eich brendan at
Wed Oct 1 15:08:13 PDT 2014

Yup, and we've talked about this at TC39 meetings. We need a 
simple-enough static analysis, and runtime errors for the residue that 
escapes that analysis. I hope this is not controversial!


Erik Arvidsson wrote:
> The static error is problematic. I'm pretty sure that engines that do 
> lazy parsing of functions is not going to report static errors before 
> doing a full parse of the function.
> I think we need to either enforce this or remove this restriction. 
> Anything in between will lead to inconsistent behavior between engines.

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