TRUE
CLIPS> (testit)
(OBJECT)
(USER OBJECT)
(USER OBJECT)
(A B USER OBJECT)
(B A USER OBJECT)
(C A B USER OBJECT)
(C A B USER OBJECT)
(A USER OBJECT)
(B USER OBJECT)
(G H A B USER OBJECT)
(G H B A USER OBJECT)
(A B T USER OBJECT)
(G A H B USER OBJECT)
(L G A H B USER OBJECT)
(C A B USER OBJECT)
(D B A USER OBJECT)
(USER OBJECT)
(USER OBJECT)
(P Q USER OBJECT)
(C A B R P Q USER OBJECT)
(C G A B USER OBJECT)
(G C A B USER OBJECT)

THE REST SHOULD BE ERRORS.

[INHERPSR5] Partial precedence list formed: C D
Precedence loop in superclasses: A B A

ERROR:
(defclass MAIN::JUNK
   (is-a C D)
INHERITANCE ERROR TEST #1 OK.
[INHERPSR5] Partial precedence list formed:
Precedence loop in superclasses: A C A

ERROR:
(defclass MAIN::JUNK
   (is-a A C)
INHERITANCE ERROR TEST #2 OK.
[INHERPSR5] Partial precedence list formed: N C O D
Precedence loop in superclasses: A B A

ERROR:
(defclass MAIN::JUNK
   (is-a N O)
INHERITANCE ERROR TEST #3 OK.
CLIPS> (dribble-off)