Re: Lexical binding: why?

[Dmitry Gutov]

On 28.05.2019 15:26, Stefan Monnier wrote:
> IIRC some operation in the js2 code was significantly slowed down (in
> Emacs-24) by lexical-binding and then (less significantly but still
> significantly) sped up when the new condition-case byte-codes were
> introduced in 24.4 (and used by default since Emacs-25), so there are
> some cases, but by and large I wouldn't expect any major change.

I think js2-mode in lexical-binding is still ~10% slower than the 
dynamic binding mode, but we switched over anyway because of the sounder 
scoping model and better compiler diagnostics.