Prune most-positive-fixnum from Lisp source

I looked through all instances of most-negative-fixnum
and most-positive-fixnum in the Lisp source code, and
when it was easy I removed assumptions that integers
fit in fixnums.  The remaining instances are either
nontrivial to fix, or are inherent to the algorithm.
* lisp/arc-mode.el (archive-l-e): Do not convert to float,
since we have bignums now.  All uses changed.
* lisp/calc/calc.el (math-bignum):
Don’t special-case most-negative-fixnum.
* lisp/calendar/parse-time.el (parse-time-string):
* lisp/emacs-lisp/edebug.el (edebug-read-special):
* lisp/emacs-lisp/package.el (package--remove-hidden):
* lisp/gnus/nnfolder.el (nnfolder-read-folder):
* lisp/international/mule-util.el (filepos-to-bufferpos--dos):
* lisp/menu-bar.el (menu-bar-update-buffers):
* lisp/net/rcirc.el (rcirc-handler-317):
* lisp/org/org-agenda.el (org-cmp-ts):
* lisp/window.el (window--resize-child-windows):
Avoid arbitrary limit to most-positive-fixnum or to
most-negative-fixnum.
* lisp/calendar/time-date.el (days-to-time):
* lisp/erc/erc-dcc.el (erc-unpack-int):
Don’t worry about integer overflow.
* lisp/cedet/semantic/wisent/comp.el (wisent-BITS-PER-WORD):
* lisp/gnus/message.el (message-unique-id):
* lisp/org/org-footnote.el (org-footnote-new):
Simplify.
* lisp/erc/erc-dcc.el (erc-most-positive-int-bytes)
(erc-most-positive-int-msb): Remove; no longer needed.
* lisp/net/imap.el (imap-string-to-integer): Remove; unused.
* lisp/org/org-element.el (org-element--cache-generate-key):
Document fixnum limitation.

2 files changed, 4 insertions, 6 deletions

diff --git a/lisp/emacs-lisp/edebug.el b/lisp/emacs-lisp/edebug.el
index fa418c68281..fb567c9cce0 100644
--- a/lisp/emacs-lisp/edebug.el
+++ b/lisp/emacs-lisp/edebug.el
@@ -894,8 +894,7 @@ circular objects.  Let `read' read everything else."
         (while (and (>= (following-char) ?0) (<= (following-char) ?9))
           (forward-char 1))
         (let ((n (string-to-number (buffer-substring start (point)))))
-          (when (and read-circle
-                     (<= n most-positive-fixnum))
+          (when read-circle
             (cond
              ((eq ?= (following-char))
               ;; Make a placeholder for #n# to use temporarily.
@@ -910,7 +909,7 @@ circular objects.  Let `read' read everything else."
                   (throw 'return (setf (cdr elem) obj)))))
              ((eq ?# (following-char))
               ;; #n# returns a previously read object.
-              (let ((elem (assq n edebug-read-objects)))
+              (let ((elem (assoc n edebug-read-objects)))
                 (when (consp elem)
                   (forward-char 1)
                   (throw 'return (cdr elem))))))))))
diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index cacc8b0c18c..2ddab653630 100644
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -2673,12 +2673,11 @@ to their archives."
                 ((not package-menu-hide-low-priority)
                  pkg-list)
                 ((eq package-menu-hide-low-priority 'archive)
-                 (let* ((max-priority most-negative-fixnum)
-                        (out))
+                 (let (max-priority out)
                    (while pkg-list
                      (let ((p (pop pkg-list)))
                        (let ((priority (package-desc-priority p)))
-                         (if (< priority max-priority)
+                         (if (and max-priority (< priority max-priority))
                              (setq pkg-list nil)
                            (push p out)
                            (setq max-priority priority)))))