Don't know if the mailing list is the best place to post bug reports. Let me know the correct way to do it.
On a clean 32 bit debian based system, fresh compilation of TCL 8.5.9 and XOTcl/Next, TCL will crash when calling "obj info has type" without arguments or with wrong arguments:
nx::Class create C C create obj obj has type tclsh: ./generic/nsf.c:9853: IsSubType: Assertion `cl && subcl' failed.