+;;; As noted by Paul Dietz for CMUCL, :CONC-NAME handling was a little
+;;; too fragile:
+(defstruct (conc-name-syntax :conc-name) a-conc-name-slot)
+(assert (eq (a-conc-name-slot (make-conc-name-syntax :a-conc-name-slot 'y))
+ 'y))
+;;; and further :CONC-NAME NIL was being wrongly treated:
+(defpackage "DEFSTRUCT-TEST-SCRATCH")
+(defstruct (conc-name-nil :conc-name)
+ defstruct-test-scratch::conc-name-nil-slot)
+(assert (= (defstruct-test-scratch::conc-name-nil-slot
+ (make-conc-name-nil :conc-name-nil-slot 1)) 1))
+(assert (raises-error? (conc-name-nil-slot (make-conc-name-nil))
+ undefined-function))
+\f
+;;; The named/typed predicates were a little fragile, in that they
+;;; could throw errors on innocuous input:
+(defstruct (list-struct (:type list) :named) a-slot)
+(assert (list-struct-p (make-list-struct)))
+(assert (not (list-struct-p nil)))
+(assert (not (list-struct-p 1)))
+(defstruct (offset-list-struct (:type list) :named (:initial-offset 1)) a-slot)
+(assert (offset-list-struct-p (make-offset-list-struct)))
+(assert (not (offset-list-struct-p nil)))
+(assert (not (offset-list-struct-p 1)))
+(assert (not (offset-list-struct-p '(offset-list-struct))))
+(assert (not (offset-list-struct-p '(offset-list-struct . 3))))
+(defstruct (vector-struct (:type vector) :named) a-slot)
+(assert (vector-struct-p (make-vector-struct)))
+(assert (not (vector-struct-p nil)))
+(assert (not (vector-struct-p #())))
+