Revert "cl-loop: Calculate the array length just once"

It fails when using 'and' (parallel bindings) for arrays (Bug#40727).
* lisp/emacs-lisp/cl-macs.el (cl--parse-loop-clause): Revert to
recomputing array length.
* test/lisp/emacs-lisp/cl-macs-tests.el (cl-macs-loop-and-arrays): New
test.

1 files changed, 6 insertions, 0 deletions

diff --git a/test/lisp/emacs-lisp/cl-macs-tests.el b/test/lisp/emacs-lisp/cl-macs-tests.el
index 9ca84f156a0..77609a42a99 100644
--- a/test/lisp/emacs-lisp/cl-macs-tests.el
+++ b/test/lisp/emacs-lisp/cl-macs-tests.el
@@ -39,6 +39,12 @@
                           collect (list c b a))
                  '((4.0 2 1) (8.3 6 5) (10.4 9 8)))))
 
+(ert-deftest cl-macs-loop-and-arrays ()
+  "Bug#40727"
+  (should (equal (cl-loop for y = (- (or x 0)) and x across [1 2]
+                          collect (cons x y))
+                 '((1 . 0) (2 . -1)))))
+
 (ert-deftest cl-macs-loop-destructure ()
   (should (equal (cl-loop for (a b c) in '((1 2 4.0) (5 6 8.3) (8 9 10.4))
                           collect (list c b a))