sequences of actions making emacs crash:

* lauch "emacs --no-site-file  --no-init-file" with $DISPLAY pointing
to a running X server.
* M-X customize-group
* icomplete
* expand "icomplete mode" node (should be initially "off")
* toggle
* goto "state"
* press "return"

Note: this sequence of  actions always leads crash but stack
backtraces are never the same.

==> config.log and gdb session typescript attached
-- 
Gilles PION