> Should we even signal an error then?  The parameter would be applied
> later anyway as soon as we can parse the display geometry.  At least
> here the frame appears as expected if my early-init.el just contains
>
> (setq default-frame-alist '((left . (- 100))))
>
> and the patch below is used.

It works here too. Please install it.

Thanks,

   Juanma