;;; return is NIL, T, because that's completely wrong. ]
(assert (subtypep '(or integer ratio) 'rational))
(assert (subtypep 'rational '(or integer ratio)))
+;;; Likewise, these are allowed to return NIL, NIL, but shouldn't
+;;; return NIL, T:
+(assert (subtypep t '(or real (not real))))
+(assert (subtypep t '(or keyword (not keyword))))
+(assert (subtypep '(and cons (not (cons symbol integer)))
+ '(or (cons (not symbol) *) (cons * (not integer)))))
+(assert (subtypep '(or (cons (not symbol) *) (cons * (not integer)))
+ '(and cons (not (cons symbol integer)))))
+(assert (subtypep '(or (eql 0) (rational (0) 10))
+ '(rational 0 10)))
+(assert (subtypep '(rational 0 10)
+ '(or (eql 0) (rational (0) 10))))
+;;; Until sbcl-0.7.13.7, union of CONS types when the CDRs were the
+;;; same type gave exceedingly wrong results
+(assert (null (subtypep '(or (cons fixnum single-float)
+ (cons bignum single-float))
+ '(cons single-float single-float))))
+(assert (subtypep '(cons integer single-float)
+ '(or (cons fixnum single-float) (cons bignum single-float))))