+
+;; arithmetic indexes can be NIL or symbols.
+(assert (equal (loop for nil from 0 to 2 collect nil)
+ '(nil nil nil)))
+(assert (equal (loop for nil to 2 collect nil)
+ '(nil nil nil)))
+
+;; although allowed by the loop syntax definition in 6.2/LOOP,
+;; 6.1.2.1.1 says: "The variable var is bound to the value of form1 in
+;; the first iteration[...]"; since we can't bind (i j) to anything,
+;; we give a program error.
+(multiple-value-bind (function warnings-p failure-p)
+ (compile nil
+ `(lambda ()
+ (loop for (i j) from 4 to 6 collect nil)))
+ (assert failure-p))
+
+;; ...and another for indexes without FROM forms (these are treated
+;; differently by the loop code right now
+(multiple-value-bind (function warnings-p failure-p)
+ (compile nil
+ `(lambda ()
+ (loop for (i j) to 6 collect nil)))
+ (assert failure-p))
+
+(assert
+ (equal
+ (let ((x 2d0))
+ (loop for d of-type double-float from 0d0 to 10d0 by x collect d))
+ '(0d0 2d0 4d0 6d0 8d0 10d0)))
+(assert
+ (equal
+ (let ((x 2d0))
+ (loop for d of-type double-float downfrom 10d0 to 0d0 by x collect d))
+ '(10d0 8d0 6d0 4d0 2d0 0d0)))
+
+(let ((fn (handler-case
+ (compile nil '(lambda ()
+ (declare (special x y))
+ (loop thereis (pop x) thereis (pop y))))
+ (warning (c) (error "Warned: ~S" c)))))
+ (let ((x (list nil nil 1))
+ (y (list nil 2 nil)))
+ (declare (special x y))
+ (assert (= (funcall fn) 2))))