Good catches...
On Jul 17, 2015, at 5:12 PM, Kevin Gibbons wrote:
> In ECMAScript 2015, functions declared at the top level of function bodies
> and of scripts are var-like and functions declared in blocks are let-like
> (visible only in that block), generally speaking. This breaks some previously
> common patterns using block-level function declarations, which were not a
> part of ECMAScript 5 but were commonly supported in browsers, albeit with
> varying semantics. Thus, the ECMAScript 6 spec has an extension (annex B.3.3)
> which is intended to minimize this breakage by allowing function declarations
> in blocks to *also* be var-like when possible. This means that they create an
> additional binding in the containing function's scope which is assigned when
> execution reaches the block function declaration.
>
> However, B.3.3 looks for functions that permit these additional bindings
> among the containing function's VarScopedDeclarations, which essentially
> consists of top-level function declarations and any var declarations.
> Importantly, it does not include any function declarations inside of blocks,
> and so will never be applied.
>
> Unfortunately, the function body's LexicallyScopedDeclarations will also fail
> to contain function declarations inside of blocks. No existing static
> semantic rule will include the desired function declarations; changing the
> spec to accommodate this may require substantial additions beyond the scope
> of this email.
Right, see fix in https://bugs.ecmascript.org/show_bug.cgi?id=4427
>
> Also, I observe that these additional compatibility steps are only performed
> for function bodies, not scripts. I'm not sure if this is intentional, but
> it's a bit counterintuitive: `(function(){ { function f(){} } f(); })();`
> continues to work with no reference errors, but `{ function f(){} } f();`
> does not.
See fix in https://bugs.ecmascript.org/show_bug.cgi?id=4428
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