I come across the problem when I open a new c source file such as test.c. In my c-mode the auto-complete-mode and the yas-minor-mode is enabled by default.
every time I write a comment start with // or /* (which both are the comment notation in C) at the very top line(i.e. the first line) of the test.c file, the minor buffer prompt [yas] Error in condition evaluation: Symbol's function definition is void: nil. there is no other side effects just the Error Prompt. with the auto-complete-mode disabled the problem is gone, I think there maybe something conflict with the two plugins
I reproduced the problem with the minimal code in dot-emacs, here is the code:
[yas] Error in condition evaluation: Symbol's function definition is void: nil
(add-to-list 'load-path "~/.emacs.d/plugins/auto-complete")
(add-to-list 'ac-dictionary-directories "~/.emacs.d/plugins/auto-complete//ac-dict")
my emacs version is GNU Emacs 24.2.1 (i386-mingw-nt6.1.7601) of 2012-08-29 on MARVIN
my auto-complete version(1.4.0) is got from the github in 2012-11-13 18:51
my yasnippet version(0.8.0) is got from the github in 2012-11-13 16:44
GNU Emacs 24.2.1 (i386-mingw-nt6.1.7601) of 2012-08-29 on MARVIN
Nice error report. I'll have a look soon.
Closes #347: can't expect THIS-COMMAND to have valid value in YAS-BUF…
Thanks for the report. However to sucessfully (require 'auto-complete) one must do
git submodule init
git submodule update
emacs -Q -L ./Source/Emacs/yasnippet\
Also it must be
(add-to-list 'ac-dictionary-directories "~/Source/Emacs/auto-complete/dict)
problem solved thanks!