bug#28501: 26.0.60; flyspell crashes when a dictionary is changed

[Eli Zaretskii]

> From: Konstantin Reich <reich-cv@yandex.ru>
> Date: Mon, 18 Sep 2017 20:07:03 +0300
> 
> Hey, i often write in two languages, so i change dictionaries in flyspell. In 
> new emacs, when i change a dictionary i get the following error:
> 
> Error in post-command-hook (flyspell-post-command-hook): (wrong-type-argument 
> stringp nil). 
> 
> To reproduce error one can eval the following code in emacs -Q:
> 
> (require 'ispell)
> (require 'flyspell)
> (flyspell-mode)
> (ispell-change-dictionary "english")
> 
> The last line can have any dictionary, which is installed in the system and 
> not the default.
> 
> I do not have such problem in emacs 25.2

Thanks, should be fixed now in the emacs-26 branch.