[alexandria-devel] (circular-tree-p '#1=(#1#))

[Anton Kovalenko]

Hi, Alexandria developers:

CIRCULAR-TREE-P has an unfortunate corner case, causing it to overflow
the stack (seen and repoted at #lisp for '#1=(#1#), but if I understand
it correctly, having a subtree like that can be dangerous as well).

The problem is caused by the end-test (of the outer DO) being run 
before the body has a first chance to check for (member slow seen).

Moving endlist into the end of the body seems to fix it.
Quick-and-dirty illustration is at <http://paste.lisp.org/+2OHW>.

-- 
Regards, Anton Kovalenko
+7(916)345-34-02 | Elektrostal' MO, Russia