"require 'langtool" causes error

[MagisDing]

I just updated package"langtool" via melpa, and got the notification of error "wrong error argument :stringp, nil". I checked my .init.el, my setting comes below:

(require 'langtool)
(setq langtool-language-tool-jar "/usr/local/Cellar/languagetool/2.8/libexec/languagetool-commandline.jar"
langtool-mother-tongue "en"
langtool-disabled-rules '("WHITESPACE_RULE"
"EN_UNPAIRED_BRACKETS"
"COMMA_PARENTHESIS_WHITESPACE"
"EN_QUOTES"))
(global-set-key (kbd "") 'langtool-check-buffer)
(global-set-key (kbd "M-") 'langtool-correct-buffer)

I surprisingly found out this issue could be "fixed" by commenting "require 'langtool", all the functions work well,is this a bug?

[mhayashi1120]

Yes, it's bug ;-) Sorry for your inconvenience.
Thanks for the report anyway.