On Nov 26, 2013, at 11:39 AM, Brendan Eich wrote:

> Brendan Eich wrote:
>>>    let["a"].foo() // Fine in ES5 non-strict, fails in ES6?
>> 
>> That old chestnut! (Unquote "a" for better ambiguity.) 
> 
> Truly hard case:
> 
>  let[x] = y;
> 
> where 'var let' or something worse, e.g., at global scope, this.let = [], has been evaluated.
> 

We decided (at a TC39 meeting) and after Brian reported some web crawling data that we could probably get away with the breaking change that disallows this formulation as an ExpressionStatement.  If anyone actually has such code, then need to change it to:
   (let[x])  = y;

or an equivalent formulation.

Allen

On Nov 26, 2013, at 11:39 AM, Brendan Eich wrote:

> Truly hard case:
> 
> ```js
>  let[x] = y;
> ```
> 
> where `var let` or something worse, e.g., at global scope, `this.let = []`, has been evaluated.
> 

We decided (at a TC39 meeting) and after Brian reported some web crawling data that we could probably get away with the breaking change that disallows this formulation as an ExpressionStatement.  If anyone actually has such code, then need to change it to:

```js
(let[x])  = y;
```

or an equivalent formulation.