* lisp/gnus: Use lexical-binding in all the files

* lisp/gnus/gnus-group.el (features): Use `dlet`.
(gnus-tmp-level, gnus-tmp-marked, gnus-tmp-group): Declare vars.
(gnus-group-insert-group-line): Bind dynbound vars via `let` rather
than as formal args.  Bind `number` as dynbound.
(gnus-visual, gnus-score-find-score-files-function)
(gnus-home-score-file, gnus-apply-kill-hook)
(gnus-summary-expunge-below): Declare vars.
(gnus-group-restart, gnus-group-list-plus): Fix `interactive` spec
since the arg is unused.

* lisp/gnus/mail-source.el (mail-source-bind, mail-source-bind-common):
Use `dlet` and suppress the warnings about the non-prefixed dynbound vars.
(mail-source-set-1): Remove unused var `auth-info`.
(mail-source-call-script): Remove unused var `background`.
(mail-source-fetch-pop, mail-source-check-pop): Bind pop3 vars with `dlet`.

* lisp/gnus/gnus-int.el (mail-source-plugged, gnus-inhibit-demon):
Declare vars.
(gnus-server-opened, gnus-status-message)
(gnus-open-server, gnus-close-server, gnus-request-list)
(gnus-finish-retrieve-group-infos, gnus-retrieve-group-data-early)
(gnus-request-list-newsgroups, gnus-request-newgroups)
(gnus-request-regenerate, gnus-request-compact, gnus-request-group)
(gnus-retrieve-groups, gnus-request-post, gnus-request-expunge-group)
(gnus-request-scan, gnus-request-update-info, gnus-request-marks)
(gnus-request-accept-article, gnus-request-create-group)
(gnus-asynchronous-p, gnus-remove-denial):
Bind `gnus-command-method` via `let` rather than as formal args.

* lisp/gnus/gnus-topic.el (gnus-topic-insert-topic-line):
Pass documented vars to eval for `gnus-topic-line-format-spec`.

* lisp/gnus/message.el (message-yank-original): Use `cl-progv` rather
than `eval` to bind the vars from `message-cite-style`.

* lisp/gnus/mml.el (mml-parse-1): Use `apply` instead of `eval`.
(gnus-newsgroup-name, gnus-displaying-mime, gnus-newsgroup-name)
(gnus-article-prepare-hook, gnus-newsgroup-charset)
(gnus-original-article-buffer, gnus-message-buffer)
(message-this-is-news, message-this-is-mail): Declare vars.

* lisp/gnus/deuglify.el (gnus-outlook-rearrange-article): Remove unused
var `cite-marks`.
* lisp/gnus/gnus-art.el (ansi-color-context-region): Declare var.
(gnus-mime-display-attachment-buttons-in-header): Move declaration
before first use.
(gnus-mime-display-alternative): Remove unused var `from`.
* lisp/gnus/gnus-bookmark.el (gnus-bookmark-bmenu-list): Remove unused
var `start` `end`.
* lisp/gnus/gnus-cache.el (gnus-article-decode-hook)
(nnml-generate-active-function): Declare var.
* lisp/gnus/gnus-cite.el (gnus-message-citation-mode): Remove unused
var `keywords`.
* lisp/gnus/gnus-cloud.el (gnus-cloud-encode-data): Remove unused var
`cipher`.
(gnus-cloud-ensure-cloud-group): Remove unused var `method`.
* lisp/gnus/gnus-delay.el (gnus-delay-article): Remove unused var `days`.
* lisp/gnus/gnus-html.el (gnus-html-wash-images): Remove unused vars
`tag`, `string`, and `images`.
(gnus-html-wash-tags): Remove unused vars `string` and `images`.
* lisp/gnus/gnus-msg.el (gnus-msg-mail): Remove unused var `group-name`.
(gnus-group-mail, gnus-group-news, gnus-summary-mail-other-window)
(gnus-summary-news-other-window):
Remove unused vars `group` and `buffer`.
(gnus-configure-posting-styles): Remove unused vars `style` and `attribute`.
* lisp/gnus/gnus-picon.el (gnus-picon-find-face): Remove unused vars
`database`, `directory`, and `instance`.
(gnus-picon-transform-newsgroups): Remove unused var `point`.
* lisp/gnus/gnus-range.el (gnus-range-difference): Remove unused var `safe`.
* lisp/gnus/gnus-score.el (gnus-score-load-file): Remove unused var
`score-fn`.
* lisp/gnus/gnus-sum.el (message-options-set-recipient): Declare var.
* lisp/gnus/gnus-undo.el (gnus-undo): Fix docstring lie.
* lisp/gnus/gnus-util.el (print-string-length)
(iswitchb-make-buflist-hook): Declare vars.
(gnus-emacs-version): Remove unused var `codename`.
(gnus-rename-file): Remove unused vars `old-name` and `new-name`.
* lisp/gnus/gnus-uu.el (gnus-uu-yenc-article): Remove unused var
`start-char`.
(gnus-asynchronous): Declare var.
* lisp/gnus/mm-partial.el (gnus-displaying-mime): Declare var.
(mm-inline-partial): Remove unused var `buffer`.
* lisp/gnus/mm-view.el (w3m-force-redisplay, w3m-safe-url-regexp)
(gnus-displaying-mime, gnus-original-article-buffer)
(gnus-article-prepare-hook): Declare vars.
* lisp/gnus/mml-smime.el (mml-smime-epg-encrypt): Remove unused var
`boundary`.
(mml-smime-epg-verify): Remove unused vars `plain` and `signature-file`.
* lisp/gnus/mml1991.el (pgg-text-mode): Declare var.
* lisp/gnus/mml2015.el (pgg-text-mode): Declare var.
(mml2015-pgg-decrypt): Remove unused var `result`.
(mml2015-epg-key-image-to-string): Remove unused var `error`.
(mml2015-epg-decrypt): Remove unused var `result`.
(mml2015-epg-verify): Remove unused vars `plain` and `signature-file`.
* lisp/gnus/nnbabyl.el (nnml-current-directory): Declare var.
* lisp/gnus/nndiary.el (nndiary-files): Move declaration before first use.
* lisp/gnus/nnfolder.el (nnfolder-request-accept-article):
Remove unused var `buf`.
* lisp/gnus/nnmail.el (nnmail-parse-active): Remove unused var `err`.
* lisp/gnus/nnmairix.el (nnmairix-request-group): Remove unused var `args`.
(nnmairix-request-create-group): Remove unused var `info`.
(nnmairix-request-list): Remove unused var `folder`.
(nnmairix-request-set-mark): Remove unused var `propto`.
(nnmairix-request-set-mark): Remove unused vars `number` and `method`.
(nnmairix-close-group): Remove unused var `method`.
(nnmairix-create-search-group-from-message): Remove unused var `cq`.
(nnmairix-create-server-and-default-group): Remove unused var `create`.
(nnmairix-purge-old-groups): Remove unused var `folder`.
(nnmairix-remove-tick-mark-original-article, nnmairix-get-valid-servers):
Remove unused var `cur`.
(nnmairix-replace-group-and-numbers): Remove unused var `header`.
(nnmairix-goto-original-article): Remove unused var `rval`.
(nnmairix-widget-create-query): Remove unused var `allwidgets`.
* lisp/gnus/nnmbox.el (nnml-current-directory): Declare var.
* lisp/gnus/nnmh.el (nnmh-toplev): Move declaration before first use.
(nnmh-request-list-1): Remove unused var `rdir`.
* lisp/gnus/nnml.el (nnml-generate-nov-file): Remove unused var `file`.
* lisp/gnus/nnrss.el (nnrss-request-article): Remove unused var `post`.
(nnrss-request-article): Remove unused var `fn`.
(nnrss-check-group): Remove unused var `rdf-ns`.
* lisp/gnus/nnweb.el (nnweb-request-article): Remove unused var `active`.
(nnweb-google-parse-1): Remove unused var `Score`.
* lisp/gnus/spam-stat.el (spam-stat-error-holder): Remove var.
(spam-stat-buffer-words-with-scores): Remove unused var `word`.
(spam-stat-score-buffer): Remove unused var `spam-stat-error-holder`.
(spam-stat-split-fancy): Use `err` instead of `spam-stat-error-holder`.
* lisp/gnus/spam-wash.el (spam-wash): Remove unused var `handle`.
* lisp/gnus/spam.el (spam-copy-or-move-routine): Remove unused vars
`article` and `mark`.
(spam-register-routine): Remove unused var `article`.
(spam-log-undo-registration): Remove unused var `found`.
(spam-ifile-register-with-ifile): Remove unused var `parameters`.
(spam-check-stat): Remove unused vars `category` and `return`.
(spam-parse-list): Remove unused var `found`.
(spam-filelist-register-routine): Remove unused var `from`.

90 files changed, 780 insertions, 667 deletions

diff --git a/lisp/gnus/canlock.el b/lisp/gnus/canlock.el
index 993050109d1..dbdbaa83d7e 100644
--- a/lisp/gnus/canlock.el
+++ b/lisp/gnus/canlock.el
@@ -1,4 +1,4 @@
-;;; canlock.el --- functions for Cancel-Lock feature
+;;; canlock.el --- functions for Cancel-Lock feature  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1998-1999, 2001-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/deuglify.el b/lisp/gnus/deuglify.el
index 3a40b55f56b..08beef7db9f 100644
--- a/lisp/gnus/deuglify.el
+++ b/lisp/gnus/deuglify.el
@@ -1,4 +1,4 @@
-;;; deuglify.el --- deuglify broken Outlook (Express) articles
+;;; deuglify.el --- deuglify broken Outlook (Express) articles  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2001-2021 Free Software Foundation, Inc.
 
@@ -336,7 +336,8 @@ NODISPLAY is non-nil, don't redisplay the article buffer."
   "Put text from ATTR-START to the end of buffer at the top of the article buffer."
   ;; FIXME: 1.  (*) text/plain          ( ) text/html
   (let ((inhibit-read-only t)
-        (cite-marks gnus-outlook-deuglify-cite-marks))
+        ;; (cite-marks gnus-outlook-deuglify-cite-marks)
+        )
     (gnus-with-article-buffer
       (article-goto-body)
       ;; article does not start with attribution
diff --git a/lisp/gnus/gmm-utils.el b/lisp/gnus/gmm-utils.el
index 3542587319d..bcf8dd014bc 100644
--- a/lisp/gnus/gmm-utils.el
+++ b/lisp/gnus/gmm-utils.el
@@ -1,4 +1,4 @@
-;;; gmm-utils.el --- Utility functions for Gnus, Message and MML
+;;; gmm-utils.el --- Utility functions for Gnus, Message and MML  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2006-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-agent.el b/lisp/gnus/gnus-agent.el
index 9af19bd02ca..86c471197d5 100644
--- a/lisp/gnus/gnus-agent.el
+++ b/lisp/gnus/gnus-agent.el
@@ -1,4 +1,4 @@
-;;; gnus-agent.el --- unplugged support for Gnus
+;;; gnus-agent.el --- unplugged support for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1997-2021 Free Software Foundation, Inc.
 
@@ -820,7 +820,7 @@ be a select method."
              (condition-case err
                  (while t
                    (let ((bgn (point)))
-                     (eval (read (current-buffer)))
+                     (eval (read (current-buffer)) t)
                      (delete-region bgn (point))))
                (end-of-file
                 (delete-file (gnus-agent-lib-file "flags")))
@@ -2666,7 +2666,7 @@ The following commands are available:
      (point)
      (prog1 (1+ (point))
        ;; Insert the text.
-       (eval gnus-category-line-format-spec))
+       (eval gnus-category-line-format-spec t))
      (list 'gnus-category gnus-tmp-name))))
 
 (defun gnus-enter-category-buffer ()
diff --git a/lisp/gnus/gnus-art.el b/lisp/gnus/gnus-art.el
index 4034d362af4..25ebc305947 100644
--- a/lisp/gnus/gnus-art.el
+++ b/lisp/gnus/gnus-art.el
@@ -1,4 +1,4 @@
-;;; gnus-art.el --- article mode commands for Gnus
+;;; gnus-art.el --- article mode commands for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
@@ -1432,7 +1432,7 @@ See Info node `(gnus)Customizing Articles' and Info node
                  (message "\
 ** gnus-treat-display-xface is an obsolete variable;\
  use gnus-treat-display-x-face instead")
-                 (eval (car (get 'gnus-treat-display-xface 'saved-value))))
+                 (eval (car (get 'gnus-treat-display-xface 'saved-value)) t))
                 (t
                  value)))))
 (put 'gnus-treat-display-x-face 'highlight t)
@@ -2162,6 +2162,8 @@ MAP is an alist where the elements are on the form (\"from\" \"to\")."
               (put-text-property
                (point) (1+ (point)) 'face 'underline)))))))))
 
+(defvar ansi-color-context-region)
+
 (defun article-treat-ansi-sequences ()
   "Translate ANSI SGR control sequences into overlays or extents."
   (interactive)
@@ -2893,7 +2895,7 @@ message header will be added to the bodies of the \"text/html\" parts."
                                           (t "<br>\n"))))
                    (goto-char (point-min))
                    (while (re-search-forward "^[\t ]+" nil t)
-                     (dotimes (i (prog1
+                     (dotimes (_ (prog1
                                      (current-column)
                                    (delete-region (match-beginning 0)
                                                   (match-end 0))))
@@ -3021,6 +3023,8 @@ message header will be added to the bodies of the \"text/html\" parts."
                (setq showed t)))))
     showed))
 
+(defvar gnus-mime-display-attachment-buttons-in-header)
+
 (defun gnus-article-browse-html-article (&optional arg)
   "View \"text/html\" parts of the current article with a WWW browser.
 Inline images embedded in a message using the cid scheme, as they are
@@ -4712,8 +4716,6 @@ If ALL-HEADERS is non-nil, no headers are hidden."
             (gnus-run-hooks 'gnus-article-prepare-hook)
             t))))))
 
-(defvar gnus-mime-display-attachment-buttons-in-header)
-
 ;;;###autoload
 (defun gnus-article-prepare-display ()
   "Make the current buffer look like a nice article."
@@ -6149,7 +6151,7 @@ If nil, don't show those extra buttons."
   (let* ((preferred (or preferred (mm-preferred-alternative handles)))
          (ihandles handles)
          (point (point))
-         handle (inhibit-read-only t) from begend not-pref)
+         handle (inhibit-read-only t) begend not-pref) ;; from
     (save-window-excursion
       (save-restriction
         (when ibegend
@@ -6170,7 +6172,8 @@ If nil, don't show those extra buttons."
                   (not (gnus-unbuttonized-mime-type-p
                         "multipart/alternative")))
           (add-text-properties
-           (setq from (point))
+           ;; (setq from
+           (point);; )
            (progn
              (insert (format "%d.  " id))
              (point))
@@ -6191,7 +6194,8 @@ If nil, don't show those extra buttons."
           ;; Do the handles
           (while (setq handle (pop handles))
             (add-text-properties
-             (setq from (point))
+             ;; (setq from
+             (point) ;; )
              (progn
                (insert (format "(%c) %-18s"
                                (if (equal handle preferred) ?* ? )
@@ -7986,13 +7990,13 @@ specified by `gnus-button-alist'."
       (article-goto-body)
       (setq beg (point))
       (while (setq entry (pop alist))
-        (setq regexp (eval (car entry)))
+        (setq regexp (eval (car entry) t))
         (goto-char beg)
         (while (re-search-forward regexp nil t)
           (let ((start (match-beginning (nth 1 entry)))
                 (end (match-end (nth 1 entry)))
                 (from (match-beginning 0)))
-            (when (and (eval (nth 2 entry))
+            (when (and (eval (nth 2 entry) t)
                        (not (gnus-button-in-region-p
                              start end 'gnus-callback)))
               ;; That optional form returned non-nil, so we add the
@@ -8083,14 +8087,14 @@ url is put as the `gnus-button-url' overlay property on the button."
                              (match-beginning 0))
                         (point-max)))
           (goto-char beg)
-          (while (re-search-forward (eval (nth 1 entry)) end t)
+          (while (re-search-forward (eval (nth 1 entry) t) end t)
             ;; Each match within a header.
             (let* ((entry (cdr entry))
                    (start (match-beginning (nth 1 entry)))
                    (end (match-end (nth 1 entry)))
                    (form (nth 2 entry)))
               (goto-char (match-end 0))
-              (when (eval form)
+              (when (eval form t)
                 (gnus-article-add-button
                  start end (nth 3 entry)
                  (buffer-substring (match-beginning (nth 4 entry))
@@ -8099,7 +8103,7 @@ url is put as the `gnus-button-url' overlay property on the button."
 
 ;;; External functions:
 
-(defun gnus-article-add-button (from to fun &optional data text)
+(defun gnus-article-add-button (from to fun &optional data _text)
   "Create a button between FROM and TO with callback FUN and data DATA."
   (add-text-properties
    from to
@@ -8312,7 +8316,7 @@ url is put as the `gnus-button-url' overlay property on the button."
       (setq indx  (match-string 1 indx))
       (Info-index indx)
       (when comma
-        (dotimes (i (with-temp-buffer
+        (dotimes (_ (with-temp-buffer
                       (insert comma)
                       ;; Note: the XEmacs version of `how-many' takes
                       ;; no optional argument.
diff --git a/lisp/gnus/gnus-bcklg.el b/lisp/gnus/gnus-bcklg.el
index d6f53e4b380..6c7ad0c4744 100644
--- a/lisp/gnus/gnus-bcklg.el
+++ b/lisp/gnus/gnus-bcklg.el
@@ -1,4 +1,4 @@
-;;; gnus-bcklg.el --- backlog functions for Gnus
+;;; gnus-bcklg.el --- backlog functions for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-bookmark.el b/lisp/gnus/gnus-bookmark.el
index c6eb2a1c1d4..bc41d5b149d 100644
--- a/lisp/gnus/gnus-bookmark.el
+++ b/lisp/gnus/gnus-bookmark.el
@@ -1,4 +1,4 @@
-;;; gnus-bookmark.el --- Bookmarks in Gnus
+;;; gnus-bookmark.el --- Bookmarks in Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2006-2021 Free Software Foundation, Inc.
 
@@ -350,7 +350,7 @@ deletion, or > if it is flagged for displaying."
       (switch-to-buffer (gnus-get-buffer-create "*Gnus Bookmark List*"))
     (set-buffer (gnus-get-buffer-create "*Gnus Bookmark List*")))
   (let ((inhibit-read-only t)
-        alist name start end)
+        alist name) ;; start end
     (erase-buffer)
     (insert "% Gnus Bookmark\n- --------\n")
     (add-text-properties (point-min) (point)
diff --git a/lisp/gnus/gnus-cache.el b/lisp/gnus/gnus-cache.el
index b17a11276c2..5ed731947bc 100644
--- a/lisp/gnus/gnus-cache.el
+++ b/lisp/gnus/gnus-cache.el
@@ -1,4 +1,4 @@
-;;; gnus-cache.el --- cache interface for Gnus
+;;; gnus-cache.el --- cache interface for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -148,6 +148,8 @@ it's not cached."
       (gnus-kill-buffer buffer)
       (setq gnus-cache-buffer nil))))
 
+(defvar gnus-article-decode-hook)
+
 (defun gnus-cache-possibly-enter-article
   (group article ticked dormant unread &optional force)
   (when (and (or force (not (eq gnus-use-cache 'passive)))
@@ -728,6 +730,8 @@ If LOW, update the lower bound instead."
       (gnus-cache-write-active t)
       (gnus-message 5 "Generating the cache active file...done"))))
 
+(defvar nnml-generate-active-function)
+
 ;;;###autoload
 (defun gnus-cache-generate-nov-databases (dir)
   "Generate NOV files recursively starting in DIR."
diff --git a/lisp/gnus/gnus-cite.el b/lisp/gnus/gnus-cite.el
index c63adb36d8b..96f1a7de5ec 100644
--- a/lisp/gnus/gnus-cite.el
+++ b/lisp/gnus/gnus-cite.el
@@ -1,4 +1,4 @@
-;;; gnus-cite.el --- parse citations in articles for Gnus
+;;; gnus-cite.el --- parse citations in articles for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -524,7 +524,7 @@ text (i.e., computer code and the like) will not be folded."
          ;; like code?  Check for ragged edges on the left.
          (< (length columns) 3))))
 
-(defun gnus-article-hide-citation (&optional arg force)
+(defun gnus-article-hide-citation (&optional arg _force)
   "Toggle hiding of all cited text except attribution lines.
 See the documentation for `gnus-article-highlight-citation'.
 If given a negative prefix, always show; if given a positive prefix,
@@ -594,7 +594,7 @@ always hide."
              (progn
                (gnus-article-add-button
                 (point)
-                (progn (eval gnus-cited-closed-text-button-line-format-spec)
+                (progn (eval gnus-cited-closed-text-button-line-format-spec t)
                        (point))
                 'gnus-article-toggle-cited-text
                 (list (cons beg end) start))
@@ -644,7 +644,8 @@ means show, nil means toggle."
             (progn (eval
                     (if hidden
                         gnus-cited-opened-text-button-line-format-spec
-                      gnus-cited-closed-text-button-line-format-spec))
+                      gnus-cited-closed-text-button-line-format-spec)
+                    t)
                    (point))
             'gnus-article-toggle-cited-text
             args)
@@ -697,7 +698,7 @@ See also the documentation for `gnus-article-highlight-citation'."
 
 ;;; Internal functions:
 
-(defun gnus-cite-parse-maybe (&optional force no-overlay)
+(defun gnus-cite-parse-maybe (&optional _force no-overlay)
   "Always parse the buffer."
   (gnus-cite-localize)
   ;;Reset parser information.
@@ -890,25 +891,25 @@ See also the documentation for `gnus-article-highlight-citation'."
                                             (regexp-quote tag) ">"))))
   ;; Find loose supercite citations after attributions.
   (gnus-cite-match-attributions 'small t
-                                (lambda (prefix tag)
+                                (lambda (_prefix tag)
                                   (when tag
                                     (concat "\\<"
                                             (regexp-quote tag)
                                             "\\>"))))
   ;; Find loose supercite citations anywhere.
   (gnus-cite-match-attributions 'small nil
-                                (lambda (prefix tag)
+                                (lambda (_prefix tag)
                                   (when tag
                                     (concat "\\<"
                                             (regexp-quote tag)
                                             "\\>"))))
   ;; Find nested citations after attributions.
   (gnus-cite-match-attributions 'small-if-unique t
-                                (lambda (prefix tag)
+                                (lambda (prefix _tag)
                                   (concat "\\`" (regexp-quote prefix) ".+")))
   ;; Find nested citations anywhere.
   (gnus-cite-match-attributions 'small nil
-                                (lambda (prefix tag)
+                                (lambda (prefix _tag)
                                   (concat "\\`" (regexp-quote prefix) ".+")))
   ;; Remove loose prefixes with too few lines.
   (let ((alist gnus-cite-loose-prefix-alist)
@@ -1137,7 +1138,7 @@ When enabled, it automatically turns on `font-lock-mode'."
   (when (derived-mode-p 'message-mode)
     ;; FIXME: Use font-lock-add-keywords!
     (let ((defaults (car font-lock-defaults))
-          default keywords)
+          default) ;; keywords
       (while defaults
         (setq default (if (consp defaults)
                           (pop defaults)
diff --git a/lisp/gnus/gnus-cloud.el b/lisp/gnus/gnus-cloud.el
index 95ebf7fbe77..3bc94f11e79 100644
--- a/lisp/gnus/gnus-cloud.el
+++ b/lisp/gnus/gnus-cloud.el
@@ -1,4 +1,4 @@
-;;; gnus-cloud.el --- storing and retrieving data via IMAP
+;;; gnus-cloud.el --- storing and retrieving data via IMAP  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2014-2021 Free Software Foundation, Inc.
 
@@ -128,7 +128,7 @@ easy interactive way to set this from the Server buffer."
 
    ((eq gnus-cloud-storage-method 'epg)
     (let ((context (epg-make-context 'OpenPGP))
-          cipher)
+          ) ;; cipher
       (setf (epg-context-armor context) t)
       (setf (epg-context-textmode context) t)
       (let ((data (epg-encrypt-string context
@@ -344,15 +344,15 @@ easy interactive way to set this from the Server buffer."
                   (group &optional previous method))
 
 (defun gnus-cloud-ensure-cloud-group ()
-  (let ((method (if (stringp gnus-cloud-method)
-                    (gnus-server-to-method gnus-cloud-method)
-                  gnus-cloud-method)))
+  ;; (let ((method (if (stringp gnus-cloud-method)
+  ;;                   (gnus-server-to-method gnus-cloud-method)
+  ;;                 gnus-cloud-method)))
     (unless (or (gnus-active gnus-cloud-group-name)
                 (gnus-activate-group gnus-cloud-group-name nil nil
                                      gnus-cloud-method))
       (and (gnus-request-create-group gnus-cloud-group-name gnus-cloud-method)
            (gnus-activate-group gnus-cloud-group-name nil nil gnus-cloud-method)
-           (gnus-subscribe-group gnus-cloud-group-name)))))
+           (gnus-subscribe-group gnus-cloud-group-name)))) ;; )
 
 (defun gnus-cloud-upload-all-data ()
   "Upload all data (newsrc and files) to the Gnus Cloud."
diff --git a/lisp/gnus/gnus-cus.el b/lisp/gnus/gnus-cus.el
index a36ef0cbec8..d8f48b19f87 100644
--- a/lisp/gnus/gnus-cus.el
+++ b/lisp/gnus/gnus-cus.el
@@ -1,4 +1,4 @@
-;;; gnus-cus.el --- customization commands for Gnus
+;;; gnus-cus.el --- customization commands for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996, 1999-2021 Free Software Foundation, Inc.
 
@@ -483,7 +483,7 @@ form, but who cares?"
     (buffer-enable-undo)
     (goto-char (point-min))))
 
-(defun gnus-group-customize-done (&rest ignore)
+(defun gnus-group-customize-done (&rest _ignore)
   "Apply changes and bury the buffer."
   (interactive)
   (let ((params (widget-value gnus-custom-params)))
@@ -927,7 +927,7 @@ articles in the thread.
     (use-local-map widget-keymap)
     (widget-setup)))
 
-(defun gnus-score-customize-done (&rest ignore)
+(defun gnus-score-customize-done (&rest _ignore)
   "Reset the score alist with the present value."
   (let ((alist gnus-custom-score-alist)
         (value (widget-value gnus-custom-scores)))
@@ -1027,14 +1027,15 @@ articles in the thread.
         (widget-create
          'push-button
          :notify
-         (lambda (&rest ignore)
+         (lambda (&rest _ignore)
            (let* ((info (assq gnus-agent-cat-name gnus-category-alist))
                   (widgets category-fields))
              (while widgets
                (let* ((widget (pop widgets))
                       (value (condition-case nil (widget-value widget) (error))))
                  (eval `(setf (,(widget-get widget :accessor) ',info)
-                              ',value)))))
+                              ',value)
+                       t))))
            (gnus-category-write)
            (gnus-kill-buffer (current-buffer))
            (when (get-buffer gnus-category-buffer)
diff --git a/lisp/gnus/gnus-delay.el b/lisp/gnus/gnus-delay.el
index 0699db405c8..0cee01b9428 100644
--- a/lisp/gnus/gnus-delay.el
+++ b/lisp/gnus/gnus-delay.el
@@ -1,4 +1,4 @@
-;;; gnus-delay.el --- Delayed posting of articles
+;;; gnus-delay.el --- Delayed posting of articles  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2001-2021 Free Software Foundation, Inc.
 
@@ -82,7 +82,7 @@ generated when the article is sent."
           gnus-delay-default-delay)))
   ;; Allow spell checking etc.
   (run-hooks 'message-send-hook)
-  (let (num unit days year month day hour minute deadline)
+  (let (num unit year month day hour minute deadline) ;; days
     (cond ((string-match
             "\\([0-9][0-9][0-9]?[0-9]?\\)-\\([0-9]+\\)-\\([0-9]+\\)"
             delay)
@@ -167,7 +167,7 @@ generated when the article is sent."
             (message "Delay header missing for article %d" article)))))))
 
 ;;;###autoload
-(defun gnus-delay-initialize (&optional no-keymap no-check)
+(defun gnus-delay-initialize (&optional _no-keymap no-check)
   "Initialize the gnus-delay package.
 This sets up a key binding in `message-mode' to delay a message.
 This tells Gnus to look for delayed messages after getting new news.
diff --git a/lisp/gnus/gnus-demon.el b/lisp/gnus/gnus-demon.el
index f85d53f70eb..e99247c0ca9 100644
--- a/lisp/gnus/gnus-demon.el
+++ b/lisp/gnus/gnus-demon.el
@@ -1,4 +1,4 @@
-;;; gnus-demon.el --- daemonic Gnus behavior
+;;; gnus-demon.el --- daemonic Gnus behavior  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-diary.el b/lisp/gnus/gnus-diary.el
index ff563d6bf30..52705640bf0 100644
--- a/lisp/gnus/gnus-diary.el
+++ b/lisp/gnus/gnus-diary.el
@@ -1,4 +1,4 @@
-;;; gnus-diary.el --- Wrapper around the NNDiary Gnus back end
+;;; gnus-diary.el --- Wrapper around the NNDiary Gnus back end  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1999-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-dired.el b/lisp/gnus/gnus-dired.el
index e412dd01a28..ca2d57de7dc 100644
--- a/lisp/gnus/gnus-dired.el
+++ b/lisp/gnus/gnus-dired.el
@@ -1,4 +1,4 @@
-;;; gnus-dired.el --- utility functions where gnus and dired meet
+;;; gnus-dired.el --- utility functions where gnus and dired meet  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-1999, 2001-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-draft.el b/lisp/gnus/gnus-draft.el
index 0752267e216..a4bcae23bd6 100644
--- a/lisp/gnus/gnus-draft.el
+++ b/lisp/gnus/gnus-draft.el
@@ -1,4 +1,4 @@
-;;; gnus-draft.el --- draft message support for Gnus
+;;; gnus-draft.el --- draft message support for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1997-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-eform.el b/lisp/gnus/gnus-eform.el
index 6d0cea7febc..265edf4d612 100644
--- a/lisp/gnus/gnus-eform.el
+++ b/lisp/gnus/gnus-eform.el
@@ -1,4 +1,4 @@
-;;; gnus-eform.el --- a mode for editing forms for Gnus
+;;; gnus-eform.el --- a mode for editing forms for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-fun.el b/lisp/gnus/gnus-fun.el
index 8ce6990804d..f69c2ed12c2 100644
--- a/lisp/gnus/gnus-fun.el
+++ b/lisp/gnus/gnus-fun.el
@@ -1,4 +1,4 @@
-;;; gnus-fun.el --- various frivolous extension functions to Gnus
+;;; gnus-fun.el --- various frivolous extension functions to Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2002-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-group.el b/lisp/gnus/gnus-group.el
index 0444b05450b..6d969609c4c 100644
--- a/lisp/gnus/gnus-group.el
+++ b/lisp/gnus/gnus-group.el
@@ -1,4 +1,4 @@
-;;; gnus-group.el --- group mode commands for Gnus
+;;; gnus-group.el --- group mode commands for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
@@ -39,8 +39,9 @@
 (eval-when-compile
   (require 'mm-url)
   (require 'subr-x)
-  (let ((features (cons 'gnus-group features)))
-    (require 'gnus-sum)))
+  (with-suppressed-warnings ((lexical features))
+    (dlet ((features (cons 'gnus-group features)))
+      (require 'gnus-sum))))
 
 (defvar gnus-cache-active-hashtb)
 
@@ -476,6 +477,9 @@ simple manner."
 
 (defvar gnus-group-edit-buffer nil)
 
+(defvar gnus-tmp-group)
+(defvar gnus-tmp-level)
+(defvar gnus-tmp-marked)
 (defvar gnus-tmp-news-method)
 (defvar gnus-tmp-colon)
 (defvar gnus-tmp-news-server)
@@ -1499,11 +1503,15 @@ if it is a string, only list groups matching REGEXP."
              (gnus-group-get-new-news 0))))
   :type 'boolean)
 
-(defun gnus-group-insert-group-line (gnus-tmp-group gnus-tmp-level
-                                                    gnus-tmp-marked number
-                                                    gnus-tmp-method)
+(defun gnus-group-insert-group-line (group level marked number gnus-tmp-method)
   "Insert a group line in the group buffer."
-  (let* ((gnus-tmp-method
+  (with-suppressed-warnings ((lexical number))
+    (defvar number))            ;FIXME: Used in `gnus-group-line-format-alist'.
+  (let* ((number number)
+         (gnus-tmp-level level)
+         (gnus-tmp-marked marked)
+         (gnus-tmp-group group)
+         (gnus-tmp-method
           (gnus-server-get-method gnus-tmp-group gnus-tmp-method))
          (gnus-tmp-active (gnus-active gnus-tmp-group))
          (gnus-tmp-number-total
@@ -1567,7 +1575,7 @@ if it is a string, only list groups matching REGEXP."
      (point)
      (prog1 (1+ (point))
        ;; Insert the text.
-       (eval gnus-group-line-format-spec))
+       (eval gnus-group-line-format-spec t))
      `(gnus-group ,gnus-tmp-group
                   gnus-unread ,(if (numberp number)
                                    (string-to-number gnus-tmp-number-of-unread)
@@ -1738,7 +1746,7 @@ already.  If INFO-UNCHANGED is non-nil, dribble buffer is not updated."
                    (buffer-modified-p gnus-dribble-buffer)
                    (with-current-buffer gnus-dribble-buffer
                      (not (zerop (buffer-size))))))
-             (mode-string (eval gformat)))
+             (mode-string (eval gformat t)))
         ;; Say whether the dribble buffer has been modified.
         (setq mode-line-modified
               (if modified "**" "--"))
@@ -1934,7 +1942,7 @@ Return nil if the group isn't displayed."
         (gnus-group-mark-group 1 nil t))
     (setq gnus-group-marked (cons group (delete group gnus-group-marked)))))
 
-(defun gnus-group-universal-argument (arg &optional groups func)
+(defun gnus-group-universal-argument (arg &optional _groups func)
   "Perform any command on all groups according to the process/prefix convention."
   (interactive "P")
   (if (eq (setq func (or func
@@ -1945,7 +1953,7 @@ Return nil if the group isn't displayed."
           'undefined)
       (gnus-error 1 "Undefined key")
     (gnus-group-iterate arg
-      (lambda (group)
+      (lambda (_group)
         (command-execute func))))
   (gnus-group-position-point))
 
@@ -2054,6 +2062,12 @@ articles in the group."
     (forward-line -1))
   (gnus-group-read-group all t))
 
+(defvar gnus-visual)
+(defvar gnus-score-find-score-files-function)
+(defvar gnus-home-score-file)
+(defvar gnus-apply-kill-hook)
+(defvar gnus-summary-expunge-below)
+
 (defun gnus-group-quick-select-group (&optional all group)
   "Select the GROUP \"quickly\".
 This means that no highlighting or scoring will be performed.  If
@@ -2511,7 +2525,7 @@ The arguments have the same meaning as those of
         (if (stringp id) (setq id (string-to-number id)))
         (setq-local debbugs-gnu-bug-number id)))))
 
-(defun gnus-group-jump-to-group (group &optional prompt)
+(defun gnus-group-jump-to-group (group &optional _prompt)
   "Jump to newsgroup GROUP.
 
 If PROMPT (the prefix) is a number, use the prompt specified in
@@ -2985,7 +2999,7 @@ and NEW-NAME will be prompted for."
   (setq method (copy-tree method))
   (let (entry)
     (while (setq entry (memq (assq 'eval method) method))
-      (setcar entry (eval (cadar entry)))))
+      (setcar entry (eval (cadar entry) t))))
   (gnus-group-make-group group method))
 
 (defun gnus-group-make-help-group (&optional noerror)
@@ -4317,9 +4331,9 @@ If FORCE, force saving whether it is necessary or not."
   (interactive "P")
   (gnus-save-newsrc-file force))
 
-(defun gnus-group-restart (&optional arg)
+(defun gnus-group-restart (&optional _arg)
   "Force Gnus to read the .newsrc file."
-  (interactive "P")
+  (interactive)
   (when (gnus-yes-or-no-p
          (format "Are you sure you want to restart Gnus? "))
     (gnus-save-newsrc-file)
@@ -4738,9 +4752,9 @@ This command may read the active file."
       (forward-char 1))
     groups))
 
-(defun gnus-group-list-plus (&optional args)
+(defun gnus-group-list-plus (&optional _args)
   "List groups plus the current selection."
-  (interactive "P")
+  (interactive)
   (let ((gnus-group-listed-groups (gnus-group-listed-groups))
         (gnus-group-list-mode gnus-group-list-mode) ;; Save it.
         func)
diff --git a/lisp/gnus/gnus-html.el b/lisp/gnus/gnus-html.el
index 6a0cc0b47dc..962d7337ecd 100644
--- a/lisp/gnus/gnus-html.el
+++ b/lisp/gnus/gnus-html.el
@@ -1,4 +1,4 @@
-;;; gnus-html.el --- Render HTML in a buffer.
+;;; gnus-html.el --- Render HTML in a buffer.  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2010-2021 Free Software Foundation, Inc.
 
@@ -151,8 +151,8 @@ fit these criteria."
 
 (defun gnus-html-wash-images ()
   "Run through current buffer and replace img tags by images."
-  (let (tag parameters string start end images
-            inhibit-images blocked-images)
+  (let ( parameters start end ;; tag string images
+         inhibit-images blocked-images)
     (if (buffer-live-p gnus-summary-buffer)
         (with-current-buffer gnus-summary-buffer
           (setq inhibit-images gnus-inhibit-images
@@ -229,7 +229,7 @@ fit these criteria."
                                (> width 4)))
                   (gnus-html-display-image url start end alt-text))))))))))
 
-(defun gnus-html-display-image (url start end &optional alt-text)
+(defun gnus-html-display-image (url _start _end &optional alt-text)
   "Display image at URL on text from START to END.
 Use ALT-TEXT for the image string."
   (or alt-text (setq alt-text "*"))
@@ -248,7 +248,7 @@ Use ALT-TEXT for the image string."
       (gnus-html-put-image (gnus-html-get-image-data url) url alt-text))))
 
 (defun gnus-html-wash-tags ()
-  (let (tag parameters string start end images url)
+  (let (tag parameters start end url) ;; string images
     (gnus-html-pre-wash)
     (gnus-html-wash-images)
 
diff --git a/lisp/gnus/gnus-int.el b/lisp/gnus/gnus-int.el
index 8bad44687b2..64928623e6a 100644
--- a/lisp/gnus/gnus-int.el
+++ b/lisp/gnus/gnus-int.el
@@ -1,4 +1,4 @@
-;;; gnus-int.el --- backend interface functions for Gnus
+;;; gnus-int.el --- backend interface functions for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
@@ -76,23 +76,25 @@ server denied."
   "The current method, for the registry.")
 
 
-(defun gnus-server-opened (gnus-command-method)
-  "Check whether a connection to GNUS-COMMAND-METHOD has been opened."
-  (unless (eq (gnus-server-status gnus-command-method)
+(defun gnus-server-opened (command-method)
+  "Check whether a connection to COMMAND-METHOD has been opened."
+  (unless (eq (gnus-server-status command-method)
               'denied)
-    (when (stringp gnus-command-method)
-      (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-    (funcall (inline (gnus-get-function gnus-command-method 'server-opened))
-             (nth 1 gnus-command-method))))
-
-(defun gnus-status-message (gnus-command-method)
-  "Return the status message from GNUS-COMMAND-METHOD.
-If GNUS-COMMAND-METHOD is a string, it is interpreted as a group
-name.  The method this group uses will be queried."
+    (let ((gnus-command-method
+           (if (stringp command-method)
+               (gnus-server-to-method command-method)
+             command-method)))
+      (funcall (inline (gnus-get-function gnus-command-method 'server-opened))
+               (nth 1 gnus-command-method)))))
+
+(defun gnus-status-message (command-method)
+  "Return the status message from COMMAND-METHOD.
+If COMMAND-METHOD is a string, it is interpreted as a group name.
+The method this group uses will be queried."
   (let ((gnus-command-method
-         (if (stringp gnus-command-method)
-             (gnus-find-method-for-group gnus-command-method)
-           gnus-command-method)))
+         (if (stringp command-method)
+             (gnus-find-method-for-group command-method)
+           command-method)))
     (funcall (gnus-get-function gnus-command-method 'status-message)
              (nth 1 gnus-command-method))))
 
@@ -265,13 +267,14 @@ If it is down, start it up (again)."
                       type form))
       (setq gnus-backend-trace-elapsed (float-time)))))
 
-(defun gnus-open-server (gnus-command-method)
-  "Open a connection to GNUS-COMMAND-METHOD."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
+(defun gnus-open-server (command-method)
+  "Open a connection to COMMAND-METHOD."
   (gnus-backend-trace :opening gnus-command-method)
-  (let ((elem (assoc gnus-command-method gnus-opened-servers))
-        (server (gnus-method-to-server-name gnus-command-method)))
+  (let* ((gnus-command-method (if (stringp command-method)
+                                  (gnus-server-to-method command-method)
+                                command-method))
+         (elem (assoc gnus-command-method gnus-opened-servers))
+         (server (gnus-method-to-server-name gnus-command-method)))
     ;; If this method was previously denied, we just return nil.
     (if (eq (nth 1 elem) 'denied)
         (progn
@@ -347,23 +350,27 @@ If it is down, start it up (again)."
           (gnus-backend-trace :opened gnus-command-method)
           result)))))
 
-(defun gnus-close-server (gnus-command-method)
-  "Close the connection to GNUS-COMMAND-METHOD."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (prog1
-      (funcall (gnus-get-function gnus-command-method 'close-server)
-               (nth 1 gnus-command-method)
-               (nthcdr 2 gnus-command-method))
-    (when-let ((elem (assoc gnus-command-method gnus-opened-servers)))
-      (setf (nth 1 elem) 'closed))))
-
-(defun gnus-request-list (gnus-command-method)
-  "Request the active file from GNUS-COMMAND-METHOD."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (funcall (gnus-get-function gnus-command-method 'request-list)
-           (nth 1 gnus-command-method)))
+(defun gnus-close-server (command-method)
+  "Close the connection to COMMAND-METHOD."
+  (let ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
+    (prog1
+        (funcall (gnus-get-function gnus-command-method 'close-server)
+                 (nth 1 gnus-command-method)
+                 (nthcdr 2 gnus-command-method))
+      (when-let ((elem (assoc gnus-command-method gnus-opened-servers)))
+        (setf (nth 1 elem) 'closed)))))
+
+(defun gnus-request-list (command-method)
+  "Request the active file from COMMAND-METHOD."
+  (let ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
+    (funcall (gnus-get-function gnus-command-method 'request-list)
+             (nth 1 gnus-command-method))))
 
 (defun gnus-server-get-active (server &optional ignored)
   "Return the active list for SERVER.
@@ -407,47 +414,57 @@ Groups matching the IGNORED regexp are excluded."
             (forward-line)))))
     groups))
 
-(defun gnus-finish-retrieve-group-infos (gnus-command-method infos data)
-  "Read and update infos from GNUS-COMMAND-METHOD."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
+(defun gnus-finish-retrieve-group-infos (command-method infos data)
+  "Read and update infos from COMMAND-METHOD."
+  (let ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
   (gnus-backend-trace :finishing gnus-command-method)
   (prog1
       (funcall (gnus-get-function gnus-command-method
                                   'finish-retrieve-group-infos)
                (nth 1 gnus-command-method)
                infos data)
-    (gnus-backend-trace :finished gnus-command-method)))
-
-(defun gnus-retrieve-group-data-early (gnus-command-method infos)
-  "Start early async retrieval of data from GNUS-COMMAND-METHOD."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (funcall (gnus-get-function gnus-command-method 'retrieve-group-data-early)
-           (nth 1 gnus-command-method)
-           infos))
-
-(defun gnus-request-list-newsgroups (gnus-command-method)
-  "Request the newsgroups file from GNUS-COMMAND-METHOD."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (funcall (gnus-get-function gnus-command-method 'request-list-newsgroups)
-           (nth 1 gnus-command-method)))
-
-(defun gnus-request-newgroups (date gnus-command-method)
-  "Request all new groups since DATE from GNUS-COMMAND-METHOD."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (let ((func (gnus-get-function gnus-command-method 'request-newgroups t)))
-    (when func
-      (funcall func date (nth 1 gnus-command-method)))))
-
-(defun gnus-request-regenerate (gnus-command-method)
-  "Request a data generation from GNUS-COMMAND-METHOD."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (funcall (gnus-get-function gnus-command-method 'request-regenerate)
-           (nth 1 gnus-command-method)))
+      (gnus-backend-trace :finished gnus-command-method))))
+
+(defun gnus-retrieve-group-data-early (command-method infos)
+  "Start early async retrieval of data from COMMAND-METHOD."
+  (let ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
+    (funcall (gnus-get-function gnus-command-method 'retrieve-group-data-early)
+             (nth 1 gnus-command-method)
+             infos)))
+
+(defun gnus-request-list-newsgroups (command-method)
+  "Request the newsgroups file from COMMAND-METHOD."
+  (let ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
+    (funcall (gnus-get-function gnus-command-method 'request-list-newsgroups)
+             (nth 1 gnus-command-method))))
+
+(defun gnus-request-newgroups (date command-method)
+  "Request all new groups since DATE from COMMAND-METHOD."
+  (let ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
+    (let ((func (gnus-get-function gnus-command-method 'request-newgroups t)))
+      (when func
+        (funcall func date (nth 1 gnus-command-method))))))
+
+(defun gnus-request-regenerate (command-method)
+  "Request a data generation from COMMAND-METHOD."
+  (let ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
+    (funcall (gnus-get-function gnus-command-method 'request-regenerate)
+             (nth 1 gnus-command-method))))
 
 (defun gnus-request-compact-group (group)
   (let* ((method (gnus-find-method-for-group group))
@@ -459,17 +476,19 @@ Groups matching the IGNORED regexp are excluded."
                    (nth 1 gnus-command-method) t)))
     result))
 
-(defun gnus-request-compact (gnus-command-method)
-  "Request groups compaction from GNUS-COMMAND-METHOD."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (funcall (gnus-get-function gnus-command-method 'request-compact)
-           (nth 1 gnus-command-method)))
+(defun gnus-request-compact (command-method)
+  "Request groups compaction from COMMAND-METHOD."
+  (let ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
+    (funcall (gnus-get-function gnus-command-method 'request-compact)
+             (nth 1 gnus-command-method))))
 
-(defun gnus-request-group (group &optional dont-check gnus-command-method info)
+(defun gnus-request-group (group &optional dont-check command-method info)
   "Request GROUP.  If DONT-CHECK, no information is required."
   (let ((gnus-command-method
-         (or gnus-command-method (inline (gnus-find-method-for-group group)))))
+         (or command-method (inline (gnus-find-method-for-group group)))))
     (when (stringp gnus-command-method)
       (setq gnus-command-method
             (inline (gnus-server-to-method gnus-command-method))))
@@ -522,12 +541,14 @@ If FETCH-OLD, retrieve all headers (or some subset thereof) in the group."
              articles (gnus-group-real-name group)
              (nth 1 gnus-command-method))))
 
-(defun gnus-retrieve-groups (groups gnus-command-method)
-  "Request active information on GROUPS from GNUS-COMMAND-METHOD."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (funcall (gnus-get-function gnus-command-method 'retrieve-groups)
-           groups (nth 1 gnus-command-method)))
+(defun gnus-retrieve-groups (groups command-method)
+  "Request active information on GROUPS from COMMAND-METHOD."
+  (let ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
+    (funcall (gnus-get-function gnus-command-method 'retrieve-groups)
+             groups (nth 1 gnus-command-method))))
 
 (defun gnus-request-type (group &optional article)
   "Return the type (`post' or `mail') of GROUP (and ARTICLE)."
@@ -715,26 +736,33 @@ from other groups -- for instance, search results and the like."
           (delete-region (point-min) (1- (point))))))
     res))
 
-(defun gnus-request-post (gnus-command-method)
-  "Post the current buffer using GNUS-COMMAND-METHOD."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (funcall (gnus-get-function gnus-command-method 'request-post)
-           (nth 1 gnus-command-method)))
+(defun gnus-request-post (command-method)
+  "Post the current buffer using COMMAND-METHOD."
+  (let ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
+    (funcall (gnus-get-function gnus-command-method 'request-post)
+             (nth 1 gnus-command-method))))
 
-(defun gnus-request-expunge-group (group gnus-command-method)
+(defun gnus-request-expunge-group (group command-method)
   "Expunge GROUP, which is removing articles that have been marked as deleted."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (funcall (gnus-get-function gnus-command-method 'request-expunge-group)
-           (gnus-group-real-name group)
-           (nth 1 gnus-command-method)))
-
-(defun gnus-request-scan (group gnus-command-method)
-  "Request a SCAN being performed in GROUP from GNUS-COMMAND-METHOD.
-If GROUP is nil, all groups on GNUS-COMMAND-METHOD are scanned."
   (let ((gnus-command-method
-         (if group (gnus-find-method-for-group group) gnus-command-method))
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
+    (funcall (gnus-get-function gnus-command-method 'request-expunge-group)
+             (gnus-group-real-name group)
+             (nth 1 gnus-command-method))))
+
+(defvar mail-source-plugged)
+(defvar gnus-inhibit-demon)
+
+(defun gnus-request-scan (group command-method)
+  "Request a SCAN being performed in GROUP from COMMAND-METHOD.
+If GROUP is nil, all groups on COMMAND-METHOD are scanned."
+  (let ((gnus-command-method
+         (if group (gnus-find-method-for-group group) command-method))
         (gnus-inhibit-demon t)
         (mail-source-plugged gnus-plugged))
     (when (or gnus-plugged
@@ -744,36 +772,40 @@ If GROUP is nil, all groups on GNUS-COMMAND-METHOD are scanned."
                (and group (gnus-group-real-name group))
                (nth 1 gnus-command-method)))))
 
-(defun gnus-request-update-info (info gnus-command-method)
+(defun gnus-request-update-info (info command-method)
   (when (gnus-check-backend-function
-         'request-update-info (car gnus-command-method))
-    (when (stringp gnus-command-method)
-      (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-    (funcall (gnus-get-function gnus-command-method 'request-update-info)
-             (gnus-group-real-name (gnus-info-group info)) info
-             (nth 1 gnus-command-method))))
-
-(defsubst gnus-request-marks (info gnus-command-method)
-  "Request that GNUS-COMMAND-METHOD update INFO."
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (when (gnus-check-backend-function
-         'request-marks (car gnus-command-method))
-    (let ((group (gnus-info-group info)))
-      (and (funcall (gnus-get-function gnus-command-method 'request-marks)
-                    (gnus-group-real-name group)
-                    info (nth 1 gnus-command-method))
-           ;; If the minimum article number is greater than 1, then all
-           ;; smaller article numbers are known not to exist; we'll
-           ;; artificially add those to the 'read range.
-           (let* ((active (gnus-active group))
-                  (min (car active)))
-             (when (> min 1)
-               (let* ((range (if (= min 2) 1 (cons 1 (1- min))))
-                      (read (gnus-info-read info))
-                      (new-read (gnus-range-add read (list range))))
-                 (setf (gnus-info-read info) new-read)))
-             info)))))
+         'request-update-info (car command-method))
+    (let ((gnus-command-method
+           (if (stringp command-method)
+               (gnus-server-to-method command-method)
+             command-method)))
+      (funcall (gnus-get-function gnus-command-method 'request-update-info)
+               (gnus-group-real-name (gnus-info-group info)) info
+               (nth 1 gnus-command-method)))))
+
+(defsubst gnus-request-marks (info command-method)
+  "Request that COMMAND-METHOD update INFO."
+  (let ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
+    (when (gnus-check-backend-function
+           'request-marks (car gnus-command-method))
+      (let ((group (gnus-info-group info)))
+        (and (funcall (gnus-get-function gnus-command-method 'request-marks)
+                      (gnus-group-real-name group)
+                      info (nth 1 gnus-command-method))
+             ;; If the minimum article number is greater than 1, then all
+             ;; smaller article numbers are known not to exist; we'll
+             ;; artificially add those to the 'read range.
+             (let* ((active (gnus-active group))
+                    (min (car active)))
+               (when (> min 1)
+                 (let* ((range (if (= min 2) 1 (cons 1 (1- min))))
+                        (read (gnus-info-read info))
+                        (new-read (gnus-range-add read (list range))))
+                   (setf (gnus-info-read info) new-read)))
+               info))))))
 
 (defun gnus-request-expire-articles (articles group &optional force)
   (let* ((gnus-command-method (gnus-find-method-for-group group))
@@ -794,7 +826,7 @@ If GROUP is nil, all groups on GNUS-COMMAND-METHOD are scanned."
           (gnus-agent-expire expired-articles group 'force))))
     not-deleted))
 
-(defun gnus-request-move-article (article group server accept-function
+(defun gnus-request-move-article (article group _server accept-function
                                           &optional last move-is-internal)
   (let* ((gnus-command-method (gnus-find-method-for-group group))
          (result (funcall (gnus-get-function gnus-command-method
@@ -807,38 +839,40 @@ If GROUP is nil, all groups on GNUS-COMMAND-METHOD are scanned."
       (gnus-agent-unfetch-articles group (list article)))
     result))
 
-(defun gnus-request-accept-article (group &optional gnus-command-method last
+(defun gnus-request-accept-article (group &optional command-method last
                                           no-encode)
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (when (and (not gnus-command-method)
-             (stringp group))
-    (setq gnus-command-method (or (gnus-find-method-for-group group)
-                                  (gnus-group-name-to-method group))))
-  (goto-char (point-max))
-  ;; Make sure there's a newline at the end of the article.
-  (unless (bolp)
-    (insert "\n"))
-  (unless no-encode
-    (let ((message-options message-options))
-      (message-options-set-recipient)
-      (save-restriction
-        (message-narrow-to-head)
-        (mail-encode-encoded-word-buffer))
-      (message-encode-message-body)))
-  (let ((gnus-command-method (or gnus-command-method
-                                 (gnus-find-method-for-group group)))
-        (result
-         (funcall
-          (gnus-get-function gnus-command-method 'request-accept-article)
-          (if (stringp group) (gnus-group-real-name group) group)
-          (cadr gnus-command-method)
-          last)))
-    (when (and gnus-agent
-               (gnus-agent-method-p gnus-command-method)
-               (cdr result))
-      (gnus-agent-regenerate-group group (list (cdr result))))
-    result))
+  (let ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method)))
+    (when (and (not gnus-command-method)
+               (stringp group))
+      (setq gnus-command-method (or (gnus-find-method-for-group group)
+                                    (gnus-group-name-to-method group))))
+    (goto-char (point-max))
+    ;; Make sure there's a newline at the end of the article.
+    (unless (bolp)
+      (insert "\n"))
+    (unless no-encode
+      (let ((message-options message-options))
+        (message-options-set-recipient)
+        (save-restriction
+          (message-narrow-to-head)
+          (mail-encode-encoded-word-buffer))
+        (message-encode-message-body)))
+    (let ((gnus-command-method (or gnus-command-method
+                                   (gnus-find-method-for-group group)))
+          (result
+           (funcall
+            (gnus-get-function gnus-command-method 'request-accept-article)
+            (if (stringp group) (gnus-group-real-name group) group)
+            (cadr gnus-command-method)
+            last)))
+      (when (and gnus-agent
+                 (gnus-agent-method-p gnus-command-method)
+                 (cdr result))
+        (gnus-agent-regenerate-group group (list (cdr result))))
+      result)))
 
 (defun gnus-request-replace-article (article group buffer &optional no-encode)
   (unless no-encode
@@ -862,13 +896,14 @@ If GROUP is nil, all groups on GNUS-COMMAND-METHOD are scanned."
              article (gnus-group-real-name group)
              (nth 1 gnus-command-method))))
 
-(defun gnus-request-create-group (group &optional gnus-command-method args)
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (let ((gnus-command-method
-         (or gnus-command-method (gnus-find-method-for-group group))))
+(defun gnus-request-create-group (group &optional command-method args)
+  (let* ((gnus-command-method
+          (or (if (stringp command-method)
+                  (gnus-server-to-method command-method)
+                command-method)
+              (gnus-find-method-for-group group))))
     (funcall (gnus-get-function gnus-command-method 'request-create-group)
-             (gnus-group-real-name group) (nth 1 gnus-command-method) args)))
+             (gnus-group-real-name group) (nth 1 gnus-command-method) args)))
 
 (defun gnus-request-delete-group (group &optional force)
   (let* ((gnus-command-method (gnus-find-method-for-group group))
@@ -902,15 +937,18 @@ If GROUP is nil, all groups on GNUS-COMMAND-METHOD are scanned."
                                          "-request-close"))))
         (funcall func)))))
 
-(defun gnus-asynchronous-p (gnus-command-method)
-  (let ((func (gnus-get-function gnus-command-method 'asynchronous-p t)))
+(defun gnus-asynchronous-p (command-method)
+  (let ((func (gnus-get-function command-method 'asynchronous-p t)))
     (when (fboundp func)
-      (funcall func))))
-
-(defun gnus-remove-denial (gnus-command-method)
-  (when (stringp gnus-command-method)
-    (setq gnus-command-method (gnus-server-to-method gnus-command-method)))
-  (let* ((elem (assoc gnus-command-method gnus-opened-servers))
+      (let ((gnus-command-method command-method))
+        (funcall func)))))
+
+(defun gnus-remove-denial (command-method)
+  (let* ((gnus-command-method
+         (if (stringp command-method)
+             (gnus-server-to-method command-method)
+           command-method))
+         (elem (assoc gnus-command-method gnus-opened-servers))
          (status (cadr elem)))
     ;; If this hasn't been opened before, we add it to the list.
     (when (eq status 'denied)
diff --git a/lisp/gnus/gnus-kill.el b/lisp/gnus/gnus-kill.el
index 20ea9831052..00a4f11c6c0 100644
--- a/lisp/gnus/gnus-kill.el
+++ b/lisp/gnus/gnus-kill.el
@@ -1,4 +1,4 @@
-;;; gnus-kill.el --- kill commands for Gnus
+;;; gnus-kill.el --- kill commands for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -275,7 +275,7 @@ If NEWSGROUP is nil, the global kill file is selected."
     (save-excursion
       (save-window-excursion
         (pop-to-buffer gnus-summary-buffer)
-        (eval (car (read-from-string string)))))))
+        (eval (car (read-from-string string)) t)))))
 
 (defun gnus-kill-file-apply-last-sexp ()
   "Apply sexp before point in current buffer to current newsgroup."
@@ -289,7 +289,7 @@ If NEWSGROUP is nil, the global kill file is selected."
         (save-excursion
           (save-window-excursion
             (pop-to-buffer gnus-summary-buffer)
-            (eval (car (read-from-string string))))))
+            (eval (car (read-from-string string)) t))))
     (ding) (gnus-message 2 "No newsgroup is selected.")))
 
 (defun gnus-kill-file-exit ()
@@ -403,9 +403,9 @@ Returns the number of articles marked as read."
               (eq (car form) 'gnus-lower))
           (progn
             (delete-region beg (point))
-            (insert (or (eval form) "")))
+            (insert (or (eval form t) "")))
         (with-current-buffer gnus-summary-buffer
-          (ignore-errors (eval form)))))
+          (ignore-errors (eval form t)))))
     (and (buffer-modified-p)
          gnus-kill-save-kill-file
          (save-buffer))
@@ -560,7 +560,7 @@ COMMAND must be a Lisp expression or a string representing a key sequence."
                          ((functionp form)
                           (funcall form))
                          (t
-                          (eval form)))))
+                          (eval form t)))))
           ;; Search article body.
           (let ((gnus-current-article nil) ;Save article pointer.
                 (gnus-last-article nil)
@@ -578,7 +578,7 @@ COMMAND must be a Lisp expression or a string representing a key sequence."
                     ((functionp form)
                      (funcall form))
                     (t
-                     (eval form)))))))
+                     (eval form t)))))))
       did-kill)))
 
 (defun gnus-execute (field regexp form &optional backward unread)
diff --git a/lisp/gnus/gnus-logic.el b/lisp/gnus/gnus-logic.el
index 105222d6797..cdfdc9b7319 100644
--- a/lisp/gnus/gnus-logic.el
+++ b/lisp/gnus/gnus-logic.el
@@ -1,4 +1,4 @@
-;;; gnus-logic.el --- advanced scoring code for Gnus
+;;; gnus-logic.el --- advanced scoring code for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-mh.el b/lisp/gnus/gnus-mh.el
index b26b736d055..fc8d9be8d6d 100644
--- a/lisp/gnus/gnus-mh.el
+++ b/lisp/gnus/gnus-mh.el
@@ -1,4 +1,4 @@
-;;; gnus-mh.el --- mh-e interface for Gnus
+;;; gnus-mh.el --- mh-e interface for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
@@ -95,7 +95,7 @@ Optional argument FOLDER specifies folder name."
           (kill-buffer errbuf))))
     (setq gnus-newsgroup-last-folder folder)))
 
-(defun gnus-Folder-save-name (newsgroup headers &optional last-folder)
+(defun gnus-Folder-save-name (newsgroup _headers &optional last-folder)
   "Generate folder name from NEWSGROUP, HEADERS, and optional LAST-FOLDER.
 If variable `gnus-use-long-file-name' is nil, it is +News.group.
 Otherwise, it is like +news/group."
@@ -105,7 +105,7 @@ Otherwise, it is like +news/group."
                   (gnus-capitalize-newsgroup newsgroup)
                 (gnus-newsgroup-directory-form newsgroup)))))
 
-(defun gnus-folder-save-name (newsgroup headers &optional last-folder)
+(defun gnus-folder-save-name (newsgroup _headers &optional last-folder)
   "Generate folder name from NEWSGROUP, HEADERS, and optional LAST-FOLDER.
 If variable `gnus-use-long-file-name' is nil, it is +news.group.
 Otherwise, it is like +news/group."
diff --git a/lisp/gnus/gnus-ml.el b/lisp/gnus/gnus-ml.el
index a47c15525a3..3b2b5a07c1d 100644
--- a/lisp/gnus/gnus-ml.el
+++ b/lisp/gnus/gnus-ml.el
@@ -1,4 +1,4 @@
-;;; gnus-ml.el --- Mailing list minor mode for Gnus
+;;; gnus-ml.el --- Mailing list minor mode for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2000-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-mlspl.el b/lisp/gnus/gnus-mlspl.el
index 77816d22eb0..d42f0971259 100644
--- a/lisp/gnus/gnus-mlspl.el
+++ b/lisp/gnus/gnus-mlspl.el
@@ -1,4 +1,4 @@
-;;; gnus-mlspl.el --- a group params-based mail splitting mechanism
+;;; gnus-mlspl.el --- a group params-based mail splitting mechanism  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1998-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-msg.el b/lisp/gnus/gnus-msg.el
index 49be7047855..1bd62516b14 100644
--- a/lisp/gnus/gnus-msg.el
+++ b/lisp/gnus/gnus-msg.el
@@ -1,4 +1,4 @@
-;;; gnus-msg.el --- mail and post interface for Gnus
+;;; gnus-msg.el --- mail and post interface for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -517,7 +517,7 @@ instead."
                       switch-action yank-action send-actions return-action))
     (let ((buf (current-buffer))
           ;; Don't use posting styles corresponding to any existing group.
-          (group-name gnus-newsgroup-name)
+          ;; (group-name gnus-newsgroup-name)
           mail-buf)
       (let ((gnus-newsgroup-name ""))
         (gnus-setup-message
@@ -610,10 +610,10 @@ If ARG is 1, prompt for a group name to find the posting style."
   (interactive "P")
   ;; We can't `let' gnus-newsgroup-name here, since that leads
   ;; to local variables leaking.
-  (let* ((group gnus-newsgroup-name)
+  (let* (;;(group gnus-newsgroup-name)
          ;; make sure last viewed article doesn't affect posting styles:
          (gnus-article-copy)
-         (buffer (current-buffer))
+         ;; (buffer (current-buffer))
          (gnus-newsgroup-name
           (if arg
               (if (= 1 (prefix-numeric-value arg))
@@ -635,10 +635,10 @@ network.  The corresponding back end must have a `request-post' method."
   (interactive "P")
   ;; We can't `let' gnus-newsgroup-name here, since that leads
   ;; to local variables leaking.
-  (let* ((group gnus-newsgroup-name)
+  (let* (;;(group gnus-newsgroup-name)
          ;; make sure last viewed article doesn't affect posting styles:
          (gnus-article-copy)
-         (buffer (current-buffer))
+         ;; (buffer (current-buffer))
          (gnus-newsgroup-name
           (if arg
               (if (= 1 (prefix-numeric-value arg))
@@ -678,10 +678,10 @@ posting style."
   (interactive "P")
   ;; We can't `let' gnus-newsgroup-name here, since that leads
   ;; to local variables leaking.
-  (let* ((group gnus-newsgroup-name)
+  (let* (;;(group gnus-newsgroup-name)
          ;; make sure last viewed article doesn't affect posting styles:
          (gnus-article-copy)
-         (buffer (current-buffer))
+         ;; (buffer (current-buffer))
          (gnus-newsgroup-name
           (if arg
               (if (= 1 (prefix-numeric-value arg))
@@ -703,10 +703,10 @@ network.  The corresponding back end must have a `request-post' method."
   (interactive "P")
   ;; We can't `let' gnus-newsgroup-name here, since that leads
   ;; to local variables leaking.
-  (let* ((group gnus-newsgroup-name)
+  (let* (;;(group gnus-newsgroup-name)
          ;; make sure last viewed article doesn't affect posting styles:
          (gnus-article-copy)
-         (buffer (current-buffer))
+         ;; (buffer (current-buffer))
          (gnus-newsgroup-name
           (if arg
               (if (= 1 (prefix-numeric-value arg))
@@ -930,7 +930,7 @@ header line with the old Message-ID."
               (run-hooks 'gnus-article-decode-hook)))))
       gnus-article-copy)))
 
-(defun gnus-post-news (post &optional group header article-buffer yank subject
+(defun gnus-post-news (post &optional group header article-buffer yank _subject
                             force-news)
   (when article-buffer
     (gnus-copy-article-buffer))
@@ -1732,7 +1732,7 @@ this is a reply."
                                  ;; Function.
                                  (funcall (car var) group))
                                 (t
-                                 (eval (car var)))))))
+                                 (eval (car var) t))))))
               (setq var (cdr var)))
             result)))
          name)
@@ -1789,7 +1789,7 @@ this is a reply."
                       (with-current-buffer gnus-summary-buffer
                         gnus-posting-styles)
                     gnus-posting-styles))
-          style match attribute value v results matched-string
+          match value v results matched-string ;; style attribute
           filep name address element)
       ;; If the group has a posting-style parameter, add it at the end with a
       ;; regexp matching everything, to be sure it takes precedence over all
@@ -1844,7 +1844,7 @@ this is a reply."
                                   (setq matched-string header)))))))
                  (t
                   ;; This is a form to be evalled.
-                  (eval match)))))
+                  (eval match t)))))
           ;; We have a match, so we set the variables.
           (dolist (attribute style)
             (setq element (pop attribute)
@@ -1875,7 +1875,7 @@ this is a reply."
                           ((boundp value)
                            (symbol-value value))))
                    ((listp value)
-                    (eval value))))
+                    (eval value t))))
             ;; Translate obsolescent value.
             (cond
              ((eq element 'signature-file)
diff --git a/lisp/gnus/gnus-notifications.el b/lisp/gnus/gnus-notifications.el
index adf23f36c01..a4d198b46e4 100644
--- a/lisp/gnus/gnus-notifications.el
+++ b/lisp/gnus/gnus-notifications.el
@@ -1,4 +1,4 @@
-;; gnus-notifications.el -- Send notification on new message in Gnus
+;; gnus-notifications.el -- Send notification on new message in Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2012-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-picon.el b/lisp/gnus/gnus-picon.el
index a33316a5267..7927b88c3de 100644
--- a/lisp/gnus/gnus-picon.el
+++ b/lisp/gnus/gnus-picon.el
@@ -1,4 +1,4 @@
-;;; gnus-picon.el --- displaying pretty icons in Gnus
+;;; gnus-picon.el --- displaying pretty icons in Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
@@ -112,7 +112,7 @@ List of pairs (KEY . GLYPH) where KEY is either a filename or an URL.")
   (let* ((address (gnus-picon-split-address address))
          (user (pop address))
          (faddress address)
-         database directory result instance base)
+         result base) ;; database directory instance
     (catch 'found
       (dolist (database gnus-picon-databases)
         (dolist (directory directories)
@@ -249,7 +249,7 @@ replacement is added."
    (gnus-article-goto-header header)
    (mail-header-narrow-to-field)
    (let ((groups (message-tokenize-header (mail-fetch-field header)))
-         spec file point)
+         spec file) ;; point
      (dolist (group groups)
        (unless (setq spec (cdr (assoc group gnus-picon-cache)))
          (setq spec (nreverse (split-string group "[.]")))
diff --git a/lisp/gnus/gnus-range.el b/lisp/gnus/gnus-range.el
index 1e5d2a066f6..6cc60cb49b3 100644
--- a/lisp/gnus/gnus-range.el
+++ b/lisp/gnus/gnus-range.el
@@ -1,4 +1,4 @@
-;;; gnus-range.el --- range and sequence functions for Gnus
+;;; gnus-range.el --- range and sequence functions for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
@@ -87,7 +87,7 @@ Both ranges must be in ascending order."
   (setq range2 (gnus-range-normalize range2))
   (let* ((new-range (cons nil (copy-sequence range1)))
          (r new-range)
-         (safe t))
+         ) ;; (safe t)
     (while (cdr r)
       (let* ((r1 (cadr r))
              (r2 (car range2))
diff --git a/lisp/gnus/gnus-rfc1843.el b/lisp/gnus/gnus-rfc1843.el
index dca55af4605..5697c870888 100644
--- a/lisp/gnus/gnus-rfc1843.el
+++ b/lisp/gnus/gnus-rfc1843.el
@@ -1,4 +1,4 @@
-;;; gnus-rfc1843.el --- HZ (rfc1843) decoding interface functions for Gnus
+;;; gnus-rfc1843.el --- HZ (rfc1843) decoding interface functions for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1998-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-salt.el b/lisp/gnus/gnus-salt.el
index d07d36e5441..e222d24b694 100644
--- a/lisp/gnus/gnus-salt.el
+++ b/lisp/gnus/gnus-salt.el
@@ -1,4 +1,4 @@
-;;; gnus-salt.el --- alternate summary mode interfaces for Gnus
+;;; gnus-salt.el --- alternate summary mode interfaces for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-1999, 2001-2021 Free Software Foundation, Inc.
 
@@ -609,7 +609,7 @@ Two predefined functions are available:
          beg end)
     (add-text-properties
      (setq beg (point))
-     (setq end (progn (eval gnus-tree-line-format-spec) (point)))
+     (setq end (progn (eval gnus-tree-line-format-spec t) (point)))
      (list 'gnus-number gnus-tmp-number))
     (when (or t (gnus-visual-p 'tree-highlight 'highlight))
       (gnus-tree-highlight-node gnus-tmp-number beg end))))
diff --git a/lisp/gnus/gnus-score.el b/lisp/gnus/gnus-score.el
index 254f0e548ce..ade0897a16a 100644
--- a/lisp/gnus/gnus-score.el
+++ b/lisp/gnus/gnus-score.el
@@ -1,4 +1,4 @@
-;;; gnus-score.el --- scoring code for Gnus
+;;; gnus-score.el --- scoring code for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -1235,7 +1235,7 @@ If FORMAT, also format the current score file."
     (let ((mark (car (gnus-score-get 'mark alist)))
           (expunge (car (gnus-score-get 'expunge alist)))
           (mark-and-expunge (car (gnus-score-get 'mark-and-expunge alist)))
-          (score-fn (car (gnus-score-get 'score-fn alist)))
+          ;; (score-fn (car (gnus-score-get 'score-fn alist)))
           (files (gnus-score-get 'files alist))
           (exclude-files (gnus-score-get 'exclude-files alist))
           (orphan (car (gnus-score-get 'orphan alist)))
@@ -1263,7 +1263,7 @@ If FORMAT, also format the current score file."
                                    (if adapt-file (cons adapt-file files)
                                      files)))))
       (when (and eval (not global))
-        (eval eval))
+        (eval eval t))
       ;; We then expand any exclude-file directives.
       (setq gnus-scores-exclude-files
             (nconc
@@ -2698,7 +2698,7 @@ the score file and its full name, including the directory.")
 
 ;;; Finding score files.
 
-(defun gnus-score-score-files (group)
+(defun gnus-score-score-files (_group)
   "Return a list of all possible score files."
   ;; Search and set any global score files.
   (when gnus-global-score-files
diff --git a/lisp/gnus/gnus-sieve.el b/lisp/gnus/gnus-sieve.el
index 70b1345ca27..5dcd079fb48 100644
--- a/lisp/gnus/gnus-sieve.el
+++ b/lisp/gnus/gnus-sieve.el
@@ -1,4 +1,4 @@
-;;; gnus-sieve.el --- Utilities to manage sieve scripts for Gnus
+;;; gnus-sieve.el --- Utilities to manage sieve scripts for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2001-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-spec.el b/lisp/gnus/gnus-spec.el
index a50d9f3a5f4..cb60108ea9c 100644
--- a/lisp/gnus/gnus-spec.el
+++ b/lisp/gnus/gnus-spec.el
@@ -1,4 +1,4 @@
-;;; gnus-spec.el --- format spec functions for Gnus
+;;; gnus-spec.el --- format spec functions for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
@@ -628,8 +628,8 @@ or to characters when given a pad value."
 If PROPS, insert the result."
   (let ((form (gnus-parse-format format alist props)))
     (if props
-        (add-text-properties (point) (progn (eval form) (point)) props)
-      (eval form))))
+        (add-text-properties (point) (progn (eval form t) (point)) props)
+      (eval form t))))
 
 (defun gnus-set-format (type &optional insertable)
   (set (intern (format "gnus-%s-line-format-spec" type))
diff --git a/lisp/gnus/gnus-srvr.el b/lisp/gnus/gnus-srvr.el
index deeb28885b8..54b5a7d5fa9 100644
--- a/lisp/gnus/gnus-srvr.el
+++ b/lisp/gnus/gnus-srvr.el
@@ -1,4 +1,4 @@
-;;; gnus-srvr.el --- virtual server support for Gnus
+;;; gnus-srvr.el --- virtual server support for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -297,7 +297,7 @@ The following commands are available:
      (point)
      (prog1 (1+ (point))
        ;; Insert the text.
-       (eval gnus-server-line-format-spec))
+       (eval gnus-server-line-format-spec t))
      (list 'gnus-server (intern gnus-tmp-name)
            'gnus-named-server (intern (gnus-method-to-server method t))))))
 
@@ -626,7 +626,7 @@ The following commands are available:
   (let ((info (gnus-server-to-method server)))
     (gnus-edit-form
      info "Showing the server."
-     (lambda (form)
+     (lambda (_form)
        (gnus-server-position-point))
      'edit-server)))
 
diff --git a/lisp/gnus/gnus-sum.el b/lisp/gnus/gnus-sum.el
index 05e49be093d..39110338c33 100644
--- a/lisp/gnus/gnus-sum.el
+++ b/lisp/gnus/gnus-sum.el
@@ -3186,7 +3186,7 @@ The following commands are available:
                           ;; Copy the global value of the variable.
                           (symbol-value (car local))
                         ;; Use the value from the list.
-                        (eval (cdr local)))))
+                        (eval (cdr local) t))))
           (set (make-local-variable (car local)) global))
       ;; Simple nil-valued local variable.
       (set (make-local-variable local) nil))))
@@ -3850,7 +3850,7 @@ buffer that was in action when the last article was fetched."
     (condition-case ()
         (put-text-property
          (point)
-         (progn (eval gnus-summary-line-format-spec) (point))
+         (progn (eval gnus-summary-line-format-spec t) (point))
          'gnus-number gnus-tmp-number)
       (error (gnus-message 5 "Error updating the summary line")))
     (when (gnus-visual-p 'summary-highlight 'highlight)
@@ -3971,14 +3971,14 @@ Input should look like this: \"Sun, 14 Oct 2001 13:34:39 +0200\"."
              (my-format "%b %d '%y"))
         (let* ((difference (time-subtract now messy-date))
                (templist gnus-user-date-format-alist)
-               (top (eval (caar templist))))
+               (top (eval (caar templist) t)))
           (while (if (numberp top) (time-less-p top difference) (not top))
             (progn
               (setq templist (cdr templist))
-              (setq top (eval (caar templist)))))
+              (setq top (eval (caar templist) t))))
           (if (stringp (cdr (car templist)))
               (setq my-format (cdr (car templist)))))
-        (format-time-string (eval my-format) messy-date))
+        (format-time-string (eval my-format t) messy-date))
     (error "  ?   ")))
 
 (defun gnus-summary-set-local-parameters (group)
@@ -3997,8 +3997,8 @@ Input should look like this: \"Sun, 14 Oct 2001 13:34:39 +0200\"."
              ;; buffer-local, whereas just parameters like `gcc-self',
              ;; `timestamp', etc. should not be bound as variables.
              (if (boundp (car elem))
-                 (set (make-local-variable (car elem)) (eval (nth 1 elem)))
-               (eval (nth 1 elem))))))))
+                 (set (make-local-variable (car elem)) (eval (nth 1 elem) t))
+               (eval (nth 1 elem) t)))))))
 
 (defun gnus-summary-read-group (group &optional show-all no-article
                                       kill-buffer no-display backward
@@ -5557,7 +5557,7 @@ or a straight list of headers."
             (setq gnus-tmp-thread thread)
             (put-text-property
              (point)
-             (progn (eval gnus-summary-line-format-spec) (point))
+             (progn (eval gnus-summary-line-format-spec t) (point))
              'gnus-number number)
             (when gnus-visual-p
               (forward-line -1)
@@ -6265,7 +6265,7 @@ If WHERE is `summary', the summary mode line format will be used."
                   ""))
                bufname-length max-len
                gnus-tmp-header) ;; passed as argument to any user-format-funcs
-          (setq mode-string (eval mformat))
+          (setq mode-string (eval mformat t))
           (setq bufname-length (if (string-match "%b" mode-string)
                                    (- (length
                                        (buffer-name
@@ -7863,7 +7863,7 @@ If BACKWARD, the previous article is selected instead of the next."
           (switch-to-buffer gnus-group-buffer)
           (when group
             (gnus-group-jump-to-group group))
-          (eval (cadr (assq key keystrokes)))
+          (eval (cadr (assq key keystrokes)) t)
           (setq group (gnus-group-group-name))
           (switch-to-buffer obuf))
         (setq ended nil))
@@ -10617,6 +10617,8 @@ confirmation before the articles are deleted."
     (gnus-set-mode-line 'summary)
     not-deleted))
 
+(defvar message-options-set-recipient)
+
 (defun gnus-summary-edit-article (&optional arg)
   "Edit the current article.
 This will have permanent effect only in mail groups.
@@ -12366,7 +12368,7 @@ save those articles instead."
                     ;; Form.
                     (save-restriction
                       (widen)
-                      (setq result (eval match)))))
+                      (setq result (eval match t)))))
               (setq split-name (cdr method))
               (cond ((stringp result)
                      (push (expand-file-name
@@ -12956,7 +12958,7 @@ treated as multipart/mixed."
                     (nomove "" nil nil ,keystroke)))
       (let ((func (gnus-summary-make-marking-command-1
                    mark (car lway) lway name)))
-        (setq func (eval func))
+        (setq func (eval func t))
         (define-key map (nth 4 lway) func)))))
 
 (defun gnus-summary-make-marking-command-1 (mark way lway name)
diff --git a/lisp/gnus/gnus-topic.el b/lisp/gnus/gnus-topic.el
index c4918485272..bbcccfee2f0 100644
--- a/lisp/gnus/gnus-topic.el
+++ b/lisp/gnus/gnus-topic.el
@@ -1,4 +1,4 @@
-;;; gnus-topic.el --- a folding minor mode for Gnus group buffers
+;;; gnus-topic.el --- a folding minor mode for Gnus group buffers  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -640,7 +640,14 @@ articles in the topic and its subtopics."
         (add-text-properties
          (point)
          (prog1 (1+ (point))
-           (eval gnus-topic-line-format-spec))
+           (eval gnus-topic-line-format-spec
+                 `((indentation . ,indentation)
+                   (visible . ,visible)
+                   (name . ,name)
+                   (level . ,level)
+                   (number-of-groups . ,number-of-groups)
+                   (total-number-of-articles . ,total-number-of-articles)
+                   (entries . ,entries))))
          (list 'gnus-topic name
                'gnus-topic-level level
                'gnus-topic-unread unread
diff --git a/lisp/gnus/gnus-undo.el b/lisp/gnus/gnus-undo.el
index 5d2f85af36c..64ed2bbad6b 100644
--- a/lisp/gnus/gnus-undo.el
+++ b/lisp/gnus/gnus-undo.el
@@ -1,4 +1,4 @@
-;;; gnus-undo.el --- minor mode for undoing in Gnus
+;;; gnus-undo.el --- minor mode for undoing in Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
@@ -153,10 +153,10 @@
     ;; We are not at a boundary...
     (setq gnus-undo-boundary-inhibit t)))
 
-(defun gnus-undo (n)
+(defun gnus-undo (_n)
   "Undo some previous changes in Gnus buffers.
-Repeat this command to undo more changes.
-A numeric argument serves as a repeat count."
+Repeat this command to undo more changes."
+  ;; FIXME: A numeric argument should serve as a repeat count.
   (interactive "p")
   (unless gnus-undo-mode
     (error "Undoing is not enabled in this buffer"))
diff --git a/lisp/gnus/gnus-util.el b/lisp/gnus/gnus-util.el
index 408293f1a16..f8d43253865 100644
--- a/lisp/gnus/gnus-util.el
+++ b/lisp/gnus/gnus-util.el
@@ -1,4 +1,4 @@
-;;; gnus-util.el --- utility functions for Gnus
+;;; gnus-util.el --- utility functions for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
@@ -681,6 +681,8 @@ yield \"nnimap:yxa\"."
   (define-key (symbol-value (intern (format "gnus-%s-mode-map" type)))
     [menu-bar edit] 'undefined))
 
+(defvar print-string-length)
+
 (defmacro gnus-bind-print-variables (&rest forms)
   "Bind print-* variables and evaluate FORMS.
 This macro is used with `prin1', `pp', etc. in order to ensure
@@ -1241,7 +1243,7 @@ sure of changing the value of `foo'."
      (setq gnus-info-buffer (current-buffer))
      (gnus-configure-windows 'info)))
 
-(defun gnus-not-ignore (&rest args)
+(defun gnus-not-ignore (&rest _args)
   t)
 
 (defvar gnus-directory-sep-char-regexp "/"
@@ -1381,6 +1383,7 @@ SPEC is a predicate specifier that contains stuff like `or', `and',
 (declare-function iswitchb-minibuffer-setup "iswitchb")
 (defvar iswitchb-temp-buflist)
 (defvar iswitchb-mode)
+(defvar iswitchb-make-buflist-hook)
 
 (defun gnus-iswitchb-completing-read (prompt collection &optional require-match
                                             initial-input history def)
@@ -1500,7 +1503,7 @@ Return nil otherwise."
 
 (defvar tool-bar-mode)
 
-(defun gnus-tool-bar-update (&rest ignore)
+(defun gnus-tool-bar-update (&rest _ignore)
   "Update the tool bar."
   (when (and (boundp 'tool-bar-mode)
              tool-bar-mode)
@@ -1526,7 +1529,7 @@ sequence, this is like `mapcar'.  With several, it is like the Common Lisp
   (if seqs2_n
       (let* ((seqs (cons seq1 seqs2_n))
              (cnt 0)
-             (heads (mapcar (lambda (seq)
+             (heads (mapcar (lambda (_seq)
                               (make-symbol (concat "head"
                                                    (int-to-string
                                                     (setq cnt (1+ cnt))))))
@@ -1560,7 +1563,7 @@ sequence, this is like `mapcar'.  With several, it is like the Common Lisp
                          ((memq 'type lst)
                           (symbol-name system-type))
                          (t nil)))
-         codename)
+         ) ;; codename
     (cond
      ((not (memq 'emacs lst))
       nil)
@@ -1576,9 +1579,9 @@ sequence, this is like `mapcar'.  With several, it is like the Common Lisp
 empty directories from OLD-PATH."
   (when (file-exists-p old-path)
     (let* ((old-dir (file-name-directory old-path))
-           (old-name (file-name-nondirectory old-path))
+           ;; (old-name (file-name-nondirectory old-path))
            (new-dir (file-name-directory new-path))
-           (new-name (file-name-nondirectory new-path))
+           ;; (new-name (file-name-nondirectory new-path))
            temp)
       (gnus-make-directory new-dir)
       (rename-file old-path new-path t)
diff --git a/lisp/gnus/gnus-uu.el b/lisp/gnus/gnus-uu.el
index e4aaf92c89c..32a87851549 100644
--- a/lisp/gnus/gnus-uu.el
+++ b/lisp/gnus/gnus-uu.el
@@ -1,4 +1,4 @@
-;;; gnus-uu.el --- extract (uu)encoded files in Gnus
+;;; gnus-uu.el --- extract (uu)encoded files in Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1985-1987, 1993-1998, 2000-2021 Free Software
 ;; Foundation, Inc.
@@ -977,7 +977,7 @@ When called interactively, prompt for REGEXP."
 (defvar gnus-uu-binhex-end-line
   ":$")
 
-(defun gnus-uu-binhex-article (buffer in-state)
+(defun gnus-uu-binhex-article (buffer _in-state)
   (let (state start-char)
     (with-current-buffer buffer
       (widen)
@@ -1014,11 +1014,11 @@ When called interactively, prompt for REGEXP."
 
 ;; yEnc
 
-(defun gnus-uu-yenc-article (buffer in-state)
+(defun gnus-uu-yenc-article (_buffer _in-state)
   (with-current-buffer gnus-original-article-buffer
     (widen)
     (let ((file-name (yenc-extract-filename))
-          state start-char)
+          state) ;; start-char
       (when (not file-name)
         (setq state (list 'wrong-type)))
 
@@ -1046,7 +1046,7 @@ When called interactively, prompt for REGEXP."
 
 ;; PostScript
 
-(defun gnus-uu-decode-postscript-article (process-buffer in-state)
+(defun gnus-uu-decode-postscript-article (process-buffer _in-state)
   (let ((state (list 'ok))
         start-char end-char file-name)
     (with-current-buffer process-buffer
@@ -1278,13 +1278,15 @@ When called interactively, prompt for REGEXP."
       (when dont-unmark-last-article
         (setq gnus-uu-has-been-grabbed (list art))))))
 
+(defvar gnus-asynchronous)
+
 ;; This function takes a list of articles and a function to apply to
 ;; each article grabbed.
 ;;
 ;; This function returns a list of files decoded if the grabbing and
 ;; the process-function has been successful and nil otherwise.
 (defun gnus-uu-grab-articles (articles process-function
-                                       &optional sloppy limit no-errors)
+                                       &optional sloppy limit _no-errors)
   (require 'gnus-async)
   (let ((state 'first)
         (gnus-asynchronous nil)
@@ -1452,10 +1454,10 @@ When called interactively, prompt for REGEXP."
           (setq subject (substring subject (match-end 0)))))
     (or part "")))
 
-(defun gnus-uu-uudecode-sentinel (process event)
+(defun gnus-uu-uudecode-sentinel (process _event)
   (delete-process (get-process process)))
 
-(defun gnus-uu-uustrip-article (process-buffer in-state)
+(defun gnus-uu-uustrip-article (process-buffer _in-state)
   ;; Uudecodes a file asynchronously.
   (with-current-buffer process-buffer
     (let ((state (list 'wrong-type))
@@ -1576,7 +1578,7 @@ Gnus might fail to display all of it.")
 
 ;; This function is used by `gnus-uu-grab-articles' to treat
 ;; a shared article.
-(defun gnus-uu-unshar-article (process-buffer in-state)
+(defun gnus-uu-unshar-article (process-buffer _in-state)
   (let ((state (list 'ok))
         start-char)
     (with-current-buffer process-buffer
diff --git a/lisp/gnus/gnus-vm.el b/lisp/gnus/gnus-vm.el
index 533b1e2a580..b7e6b2a8890 100644
--- a/lisp/gnus/gnus-vm.el
+++ b/lisp/gnus/gnus-vm.el
@@ -1,4 +1,4 @@
-;;; gnus-vm.el --- vm interface for Gnus
+;;; gnus-vm.el --- vm interface for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/gnus-win.el b/lisp/gnus/gnus-win.el
index d8b037ebe4e..8ac4e39fa52 100644
--- a/lisp/gnus/gnus-win.el
+++ b/lisp/gnus/gnus-win.el
@@ -1,4 +1,4 @@
-;;; gnus-win.el --- window configuration functions for Gnus
+;;; gnus-win.el --- window configuration functions for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
@@ -246,7 +246,7 @@ See the Gnus manual for an explanation of the syntax used.")
     ;; return a new SPLIT.
     (while (and (not (assq (car split) gnus-window-to-buffer))
                 (symbolp (car split)) (fboundp (car split)))
-      (setq split (eval split)))
+      (setq split (eval split t)))
     (let* ((type (car split))
            (subs (cddr split))
            (len (if (eq type 'horizontal) (window-width) (window-height)))
@@ -323,7 +323,7 @@ See the Gnus manual for an explanation of the syntax used.")
             (setq sub (append (pop subs) nil))
             (while (and (not (assq (car sub) gnus-window-to-buffer))
                         (symbolp (car sub)) (fboundp (car sub)))
-              (setq sub (eval sub)))
+              (setq sub (eval sub t)))
             (when sub
               (push sub comp-subs)
               (setq size (cadar comp-subs))
@@ -471,7 +471,7 @@ should have point."
       ;; return a new SPLIT.
       (while (and (not (assq (car split) gnus-window-to-buffer))
                   (symbolp (car split)) (fboundp (car split)))
-        (setq split (eval split)))
+        (setq split (eval split t)))
 
       (setq type (elt split 0))
       (cond
diff --git a/lisp/gnus/gnus.el b/lisp/gnus/gnus.el
index 1eff9a82230..84e53da297b 100644
--- a/lisp/gnus/gnus.el
+++ b/lisp/gnus/gnus.el
@@ -3724,7 +3724,7 @@ just the host name."
                                depth (+ depth 1)))
                        depth))))
     ;; Separate foreign select method from group name and collapse.
-   ;; If method contains a server, collapse to non-domain server name,
+    ;; If method contains a server, collapse to non-domain server name,
     ;; otherwise collapse to select method.
     (let* ((colon (string-match ":" group))
            (server (and colon (substring group 0 colon)))
diff --git a/lisp/gnus/gssapi.el b/lisp/gnus/gssapi.el
index 20562fb9ad2..6ff2a4e2851 100644
--- a/lisp/gnus/gssapi.el
+++ b/lisp/gnus/gssapi.el
@@ -1,4 +1,4 @@
-;;; gssapi.el --- GSSAPI/Kerberos 5 interface for Emacs
+;;; gssapi.el --- GSSAPI/Kerberos 5 interface for Emacs  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2011-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/legacy-gnus-agent.el b/lisp/gnus/legacy-gnus-agent.el
index b47e69ffa4b..091e3899c26 100644
--- a/lisp/gnus/legacy-gnus-agent.el
+++ b/lisp/gnus/legacy-gnus-agent.el
@@ -1,4 +1,4 @@
-;;; gnus-agent.el --- Legacy unplugged support for Gnus
+;;; gnus-agent.el --- Legacy unplugged support for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2004-2021 Free Software Foundation, Inc.
 
@@ -210,7 +210,7 @@ converted to the compressed format."
 ;; Therefore, hide the default prompt.
 (gnus-convert-mark-converter-prompt 'gnus-agent-unlist-expire-days t)
 
-(defun gnus-agent-unhook-expire-days (converting-to)
+(defun gnus-agent-unhook-expire-days (_converting-to)
   "Remove every lambda from `gnus-group-prepare-hook' that mention the
 symbol `gnus-agent-do-once' in their definition.  This should NOT be
 necessary as gnus-agent.el no longer adds them.  However, it is
diff --git a/lisp/gnus/mail-source.el b/lisp/gnus/mail-source.el
index 4f02d86f441..af0a1983766 100644
--- a/lisp/gnus/mail-source.el
+++ b/lisp/gnus/mail-source.el
@@ -1,4 +1,4 @@
-;;; mail-source.el --- functions for fetching mail
+;;; mail-source.el --- functions for fetching mail  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1999-2021 Free Software Foundation, Inc.
 
@@ -403,16 +403,19 @@ of the second `let' form.
 The variables bound and their default values are described by
 the `mail-source-keyword-map' variable."
   (declare (indent 1) (debug (sexp body)))
-  `(let* ,(mail-source-bind-1 (car type-source))
-     (mail-source-set-1 ,(cadr type-source))
-     ,@body))
-
+  ;; FIXME: Use lexical vars, i.e. don't initialize the vars inside
+  ;; `mail-source-set-1' via `set'.
+  (let ((bindings (mail-source-bind-1 (car type-source))))
+    `(with-suppressed-warnings ((lexical ,@(mapcar #'car bindings)))
+       (dlet ,bindings
+         (mail-source-set-1 ,(cadr type-source))
+         ,@body))))
 
 (defun mail-source-set-1 (source)
   (let* ((type (pop source))
          (defaults (cdr (assq type mail-source-keyword-map)))
          (search '(:max 1))
-         found default value keyword auth-info user-auth pass-auth)
+         found default value keyword user-auth pass-auth) ;; auth-info
 
     ;; append to the search the useful info from the source and the defaults:
     ;; user, host, and port
@@ -494,9 +497,13 @@ the `mail-source-keyword-map' variable."
   "Return a `let' form that binds all common variables.
 See `mail-source-bind'."
   (declare (indent 1) (debug (sexp body)))
-  `(let ,(mail-source-bind-common-1)
-     (mail-source-set-common-1 ,source)
-     ,@body))
+  ;; FIXME: AFAICT this is a Rube Goldberg'esque way to bind and initialize the
+  ;; `plugged` variable.
+  (let ((bindings (mail-source-bind-common-1)))
+    `(with-suppressed-warnings ((lexical ,@(mapcar #'car bindings)))
+       (dlet ,bindings
+         (mail-source-set-common-1 ,source)
+         ,@body))))
 
 (defun mail-source-value (value)
   "Return the value of VALUE."
@@ -506,7 +513,7 @@ See `mail-source-bind'."
     value)
    ;; Function
    ((and (listp value) (symbolp (car value)) (fboundp (car value)))
-    (eval value))
+    (eval value t))
    ;; Just return the value.
    (t
     value)))
@@ -721,12 +728,13 @@ Deleting old (> %s day(s)) incoming mail file `%s'." diff bfile)
 (declare-function gnus-get-buffer-create "gnus" (name))
 (defun mail-source-call-script (script)
   (require 'gnus)
-  (let ((background nil)
+  (let (;; (background nil)
         (stderr (gnus-get-buffer-create " *mail-source-stderr*"))
         result)
     (when (string-match "& *$" script)
       (setq script (substring script 0 (match-beginning 0))
-            background 0))
+            ;; background 0
+            ))
     (setq result
           (call-process shell-file-name nil stderr nil
                         shell-command-switch script))
@@ -810,14 +818,14 @@ Deleting old (> %s day(s)) incoming mail file `%s'." diff bfile)
              ;; The default is to use pop3.el.
              (t
               (require 'pop3)
-              (let ((pop3-password password)
-                    (pop3-maildrop user)
-                    (pop3-mailhost server)
-                    (pop3-port port)
-                    (pop3-authentication-scheme
-                     (if (eq authentication 'apop) 'apop 'pass))
-                    (pop3-stream-type stream)
-                    (pop3-leave-mail-on-server leave))
+              (dlet ((pop3-password password)
+                     (pop3-maildrop user)
+                     (pop3-mailhost server)
+                     (pop3-port port)
+                     (pop3-authentication-scheme
+                      (if (eq authentication 'apop) 'apop 'pass))
+                     (pop3-stream-type stream)
+                     (pop3-leave-mail-on-server leave))
                 (if (or debug-on-quit debug-on-error)
                     (save-excursion (pop3-movemail mail-source-crash-box))
                   (condition-case err
@@ -877,12 +885,12 @@ Deleting old (> %s day(s)) incoming mail file `%s'." diff bfile)
              ;; The default is to use pop3.el.
              (t
               (require 'pop3)
-              (let ((pop3-password password)
-                    (pop3-maildrop user)
-                    (pop3-mailhost server)
-                    (pop3-port port)
-                    (pop3-authentication-scheme
-                     (if (eq authentication 'apop) 'apop 'pass)))
+              (dlet ((pop3-password password)
+                     (pop3-maildrop user)
+                     (pop3-mailhost server)
+                     (pop3-port port)
+                     (pop3-authentication-scheme
+                      (if (eq authentication 'apop) 'apop 'pass)))
                 (if (or debug-on-quit debug-on-error)
                     (save-excursion (pop3-get-message-count))
                   (condition-case err
diff --git a/lisp/gnus/message.el b/lisp/gnus/message.el
index 3f671193a29..d2a0092fde9 100644
--- a/lisp/gnus/message.el
+++ b/lisp/gnus/message.el
@@ -3675,7 +3675,7 @@ are null."
              ((functionp message-signature)
               (funcall message-signature))
              ((listp message-signature)
-              (eval message-signature))
+              (eval message-signature t))
              (t message-signature)))
            signature-file)
       (setq signature
@@ -3992,11 +3992,12 @@ Just \\[universal-argument] as argument means don't indent, insert no
 prefix, and don't delete any headers."
   (interactive "P")
   ;; eval the let forms contained in message-cite-style
-  (eval
-   `(let ,(if (symbolp message-cite-style)
-              (symbol-value message-cite-style)
-            message-cite-style)
-      (message--yank-original-internal ',arg))))
+  (let ((bindings (if (symbolp message-cite-style)
+                      (symbol-value message-cite-style)
+                    message-cite-style)))
+    (cl-progv (mapcar #'car bindings)
+        (mapcar (lambda (binding) (eval (cadr binding) t)) bindings)
+      (message--yank-original-internal arg))))
 
 (defun message-yank-buffer (buffer)
   "Insert BUFFER into the current buffer and quote it."
@@ -4627,7 +4628,7 @@ Valid types are `send', `return', `exit', `kill' and `postpone'."
         (funcall action))
        ;; Something to be evalled.
        (t
-        (eval action))))))
+        (eval action t))))))
 
 (defun message-send-mail-partially ()
   "Send mail as message/partial."
@@ -4943,7 +4944,7 @@ that instead."
             ;; Insert an extra newline if we need it to work around
             ;; Sun's bug that swallows newlines.
             (goto-char (1+ delimline))
-            (when (eval message-mailer-swallows-blank-line)
+            (when (eval message-mailer-swallows-blank-line t)
               (newline))
             (when message-interactive
               (with-current-buffer errbuf
diff --git a/lisp/gnus/mm-archive.el b/lisp/gnus/mm-archive.el
index 6173d86327a..d550045e0a2 100644
--- a/lisp/gnus/mm-archive.el
+++ b/lisp/gnus/mm-archive.el
@@ -1,4 +1,4 @@
-;;; mm-archive.el --- Functions for parsing archive files as MIME
+;;; mm-archive.el --- Functions for parsing archive files as MIME  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2012-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/mm-bodies.el b/lisp/gnus/mm-bodies.el
index f35ba3a0b91..d6b71f15e54 100644
--- a/lisp/gnus/mm-bodies.el
+++ b/lisp/gnus/mm-bodies.el
@@ -1,4 +1,4 @@
-;;; mm-bodies.el --- Functions for decoding MIME things
+;;; mm-bodies.el --- Functions for decoding MIME things  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1998-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/mm-encode.el b/lisp/gnus/mm-encode.el
index 31d613146b3..84a3b0a8d1c 100644
--- a/lisp/gnus/mm-encode.el
+++ b/lisp/gnus/mm-encode.el
@@ -1,4 +1,4 @@
-;;; mm-encode.el --- Functions for encoding MIME things
+;;; mm-encode.el --- Functions for encoding MIME things  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1998-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/mm-partial.el b/lisp/gnus/mm-partial.el
index 8d4913e6fbd..8f5d45d67d8 100644
--- a/lisp/gnus/mm-partial.el
+++ b/lisp/gnus/mm-partial.el
@@ -1,4 +1,4 @@
-;;; mm-partial.el --- showing message/partial
+;;; mm-partial.el --- showing message/partial  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2000-2021 Free Software Foundation, Inc.
 
@@ -50,6 +50,8 @@
                   (push nhandles phandles))))))))
     phandles))
 
+(defvar gnus-displaying-mime)
+
 ;;;###autoload
 (defun mm-inline-partial (handle &optional no-display)
   "Show the partial part of HANDLE.
@@ -60,7 +62,7 @@ If NO-DISPLAY is nil, display it.  Otherwise, do nothing after replacing."
         phandles
         (b (point)) (n 1) total
         phandle nn ntotal
-        gnus-displaying-mime handles buffer)
+        gnus-displaying-mime handles) ;; buffer
     (unless (mm-handle-cache handle)
       (unless id
         (error "Can not find message/partial id"))
diff --git a/lisp/gnus/mm-url.el b/lisp/gnus/mm-url.el
index 01d25ac61e4..3d58738d637 100644
--- a/lisp/gnus/mm-url.el
+++ b/lisp/gnus/mm-url.el
@@ -1,4 +1,4 @@
-;;; mm-url.el --- a wrapper of url functions/commands for Gnus
+;;; mm-url.el --- a wrapper of url functions/commands for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2001-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/mm-util.el b/lisp/gnus/mm-util.el
index be279b6cf1f..92e04f9d2ee 100644
--- a/lisp/gnus/mm-util.el
+++ b/lisp/gnus/mm-util.el
@@ -160,7 +160,7 @@ is not available."
            form
            (prog2
                ;; Avoid errors...
-               (condition-case nil (eval form) (error nil))
+               (condition-case nil (eval form t) (error nil))
                ;; (message "Failed to eval `%s'" form))
                (mm-coding-system-p cs)
              (message "Added charset `%s' via `mm-charset-eval-alist'" cs))
diff --git a/lisp/gnus/mm-view.el b/lisp/gnus/mm-view.el
index 266f471a3fd..f4c1cf9a6c8 100644
--- a/lisp/gnus/mm-view.el
+++ b/lisp/gnus/mm-view.el
@@ -1,4 +1,4 @@
-;;; mm-view.el --- functions for viewing MIME objects
+;;; mm-view.el --- functions for viewing MIME objects  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1998-2021 Free Software Foundation, Inc.
 
@@ -137,7 +137,7 @@ This is only used if `mm-inline-large-images' is set to
                  (equal "multipart" (mm-handle-media-supertype elem)))
         (mm-w3m-cid-retrieve-1 url elem)))))
 
-(defun mm-w3m-cid-retrieve (url &rest args)
+(defun mm-w3m-cid-retrieve (url &rest _args)
   "Insert a content pointed by URL if it has the cid: scheme."
   (when (string-match "\\`cid:" url)
     (or (catch 'found-handle
@@ -149,6 +149,9 @@ This is only used if `mm-inline-large-images' is set to
             nil
           (message "Failed to find \"Content-ID: %s\"" url)))))
 
+(defvar w3m-force-redisplay)
+(defvar w3m-safe-url-regexp)
+
 (defun mm-inline-text-html-render-with-w3m (handle)
   "Render a text/html part using emacs-w3m."
   (mm-setup-w3m)
@@ -396,7 +399,7 @@ This is only used if `mm-inline-large-images' is set to
           (delete-region ,(copy-marker b t)
                          ,(point-marker)))))))
 
-(defun mm-inline-audio (handle)
+(defun mm-inline-audio (_handle)
   (message "Not implemented"))
 
 (defun mm-view-message ()
@@ -413,6 +416,10 @@ This is only used if `mm-inline-large-images' is set to
   (fundamental-mode)
   (goto-char (point-min)))
 
+(defvar gnus-original-article-buffer)
+(defvar gnus-article-prepare-hook)
+(defvar gnus-displaying-mime)
+
 (defun mm-inline-message (handle)
   (let ((b (point))
         (bolp (bolp))
diff --git a/lisp/gnus/mml-sec.el b/lisp/gnus/mml-sec.el
index a050fe04e1b..8d01d15ca01 100644
--- a/lisp/gnus/mml-sec.el
+++ b/lisp/gnus/mml-sec.el
@@ -1,4 +1,4 @@
-;;; mml-sec.el --- A package with security functions for MML documents
+;;; mml-sec.el --- A package with security functions for MML documents  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2000-2021 Free Software Foundation, Inc.
 
@@ -622,7 +622,7 @@ Passphrase caching in Emacs is NOT recommended.  Use gpg-agent instead."
                     mml-smime-passphrase-cache-expiry)
                mml-secure-passphrase-cache-expiry))))
 
-(defun mml-secure-passphrase-callback (context key-id standard)
+(defun mml-secure-passphrase-callback (context key-id _standard)
   "Ask for passphrase in CONTEXT for KEY-ID for STANDARD.
 The passphrase is read and cached."
   ;; Based on mml2015-epg-passphrase-callback.
@@ -906,7 +906,7 @@ If no one is selected, symmetric encryption will be performed.  "
         (error "No recipient specified")))
     recipients))
 
-(defun mml-secure-epg-encrypt (protocol cont &optional sign)
+(defun mml-secure-epg-encrypt (protocol _cont &optional sign)
   ;; Based on code appearing inside mml2015-epg-encrypt.
   (let* ((context (epg-make-context protocol))
          (config (epg-find-configuration 'OpenPGP))
diff --git a/lisp/gnus/mml-smime.el b/lisp/gnus/mml-smime.el
index eabb56b3038..5c133e680af 100644
--- a/lisp/gnus/mml-smime.el
+++ b/lisp/gnus/mml-smime.el
@@ -1,4 +1,4 @@
-;;; mml-smime.el --- S/MIME support for MML
+;;; mml-smime.el --- S/MIME support for MML  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2000-2021 Free Software Foundation, Inc.
 
@@ -129,7 +129,7 @@ Whether the passphrase is cached at all is controlled by
     (if func
         (funcall func handle ctl))))
 
-(defun mml-smime-openssl-sign (cont)
+(defun mml-smime-openssl-sign (_cont)
   (when (null smime-keys)
     (customize-variable 'smime-keys)
     (error "No S/MIME keys configured, use customize to add your key"))
@@ -309,7 +309,7 @@ Whether the passphrase is cached at all is controlled by
                  (buffer-string) "\n")))))
   handle)
 
-(defun mml-smime-openssl-verify-test (handle ctl)
+(defun mml-smime-openssl-verify-test (_handle _ctl)
   smime-openssl-program)
 
 (defvar epg-user-id-alist)
@@ -370,7 +370,7 @@ Content-Disposition: attachment; filename=smime.p7s
 
 (defun mml-smime-epg-encrypt (cont)
   (let* ((inhibit-redisplay t)        ;FIXME: Why?
-         (boundary (mml-compute-boundary cont))
+         ;; (boundary (mml-compute-boundary cont))
          (cipher (mml-secure-epg-encrypt 'CMS cont)))
     (delete-region (point-min) (point-max))
     (goto-char (point-min))
@@ -388,7 +388,7 @@ Content-Disposition: attachment; filename=smime.p7m
 (defun mml-smime-epg-verify (handle ctl)
   (catch 'error
     (let ((inhibit-redisplay t)
-          context plain signature-file part signature)
+          context part signature) ;; plain signature-file
       (when (or (null (setq part (mm-find-raw-part-by-type
                                   ctl (or (mm-handle-multipart-ctl-parameter
                                            ctl 'protocol)
@@ -407,7 +407,8 @@ Content-Disposition: attachment; filename=smime.p7m
       (setq part (replace-regexp-in-string "\n" "\r\n" part)
             context (epg-make-context 'CMS))
       (condition-case error
-          (setq plain (epg-verify-string context (mm-get-part signature) part))
+          ;; (setq plain
+          (epg-verify-string context (mm-get-part signature) part) ;;)
         (error
          (mm-sec-error 'gnus-info "Failed")
          (mm-sec-status 'gnus-details (if (eq (car error) 'quit)
@@ -419,7 +420,7 @@ Content-Disposition: attachment; filename=smime.p7m
        (epg-verify-result-to-string (epg-context-result-for context 'verify)))
       handle)))
 
-(defun mml-smime-epg-verify-test (handle ctl)
+(defun mml-smime-epg-verify-test (_handle _ctl)
   t)
 
 (provide 'mml-smime)
diff --git a/lisp/gnus/mml.el b/lisp/gnus/mml.el
index 54f8715baf0..f77e5c6434e 100644
--- a/lisp/gnus/mml.el
+++ b/lisp/gnus/mml.el
@@ -1,4 +1,4 @@
-;;; mml.el --- A package for parsing and validating MML documents
+;;; mml.el --- A package for parsing and validating MML documents  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1998-2021 Free Software Foundation, Inc.
 
@@ -259,18 +259,19 @@ part.  This is for the internal use, you should never modify the value.")
                             (list "sign" method "encrypt" method))
                            (t
                             (error "Unknown secure mode %s" mode))))
-          (eval `(mml-insert-tag ,secure-mode
-                                 ,@tags
-                                 ,(if keyfile "keyfile")
-                                 ,keyfile
-                                 ,@(apply #'append
-                                          (mapcar (lambda (certfile)
-                                                    (list "certfile" certfile))
-                                                  certfiles))
-                                 ,(if recipients "recipients")
-                                 ,recipients
-                                 ,(if sender "sender")
-                                 ,sender))
+          (apply #'mml-insert-tag
+                 secure-mode
+                 `(,@tags
+                   ,(if keyfile "keyfile")
+                   ,keyfile
+                   ,@(apply #'append
+                            (mapcar (lambda (certfile)
+                                      (list "certfile" certfile))
+                                    certfiles))
+                   ,(if recipients "recipients")
+                   ,recipients
+                   ,(if sender "sender")
+                   ,sender))
           ;; restart the parse
           (goto-char location)))
        ((looking-at "<#multipart")
@@ -1458,7 +1459,7 @@ will be computed and used."
                  (file-name-nondirectory file)))
       (goto-char head))))
 
-(defun mml-dnd-attach-file (uri action)
+(defun mml-dnd-attach-file (uri _action)
   "Attach a drag and drop file.
 
 Ask for type, description or disposition according to
@@ -1589,6 +1590,16 @@ Should be adopted if code in `message-send-mail' is changed."
 (declare-function message-generate-headers      "message" (headers))
 (declare-function message-sort-headers          "message" ())
 
+(defvar gnus-newsgroup-name)
+(defvar gnus-displaying-mime)
+(defvar gnus-newsgroup-name)
+(defvar gnus-article-prepare-hook)
+(defvar gnus-newsgroup-charset)
+(defvar gnus-original-article-buffer)
+(defvar gnus-message-buffer)
+(defvar message-this-is-news)
+(defvar message-this-is-mail)
+
 (defun mml-preview (&optional raw)
   "Display current buffer with Gnus, in a new buffer.
 If RAW, display a raw encoded MIME message.
@@ -1708,7 +1719,7 @@ or the `pop-to-buffer' function."
       cont)
     (let ((alist mml-tweak-sexp-alist))
       (while alist
-        (if (eval (caar alist))
+        (if (eval (caar alist) t)
             (funcall (cdar alist) cont))
         (setq alist (cdr alist)))))
   cont)
diff --git a/lisp/gnus/mml1991.el b/lisp/gnus/mml1991.el
index a87e642c07d..05f44a1cbd8 100644
--- a/lisp/gnus/mml1991.el
+++ b/lisp/gnus/mml1991.el
@@ -1,4 +1,4 @@
-;;; mml1991.el --- Old PGP message format (RFC 1991) support for MML
+;;; mml1991.el --- Old PGP message format (RFC 1991) support for MML  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1998-2021 Free Software Foundation, Inc.
 
@@ -82,7 +82,7 @@ Whether the passphrase is cached at all is controlled by
 (defvar mml1991-decrypt-function 'mailcrypt-decrypt)
 (defvar mml1991-verify-function 'mailcrypt-verify)
 
-(defun mml1991-mailcrypt-sign (cont)
+(defun mml1991-mailcrypt-sign (_cont)
   (let ((text (current-buffer))
         headers signature
         (result-buffer (get-buffer-create "*GPG Result*")))
@@ -118,7 +118,7 @@ Whether the passphrase is cached at all is controlled by
 (declare-function mc-encrypt-generic "ext:mc-toplev"
                   (&optional recipients scheme start end from sign))
 
-(defun mml1991-mailcrypt-encrypt (cont &optional sign)
+(defun mml1991-mailcrypt-encrypt (_cont &optional sign)
   (let ((text (current-buffer))
         (mc-pgp-always-sign
          (or mc-pgp-always-sign
@@ -171,8 +171,9 @@ Whether the passphrase is cached at all is controlled by
 (defvar pgg-default-user-id)
 (defvar pgg-errors-buffer)
 (defvar pgg-output-buffer)
+(defvar pgg-text-mode)
 
-(defun mml1991-pgg-sign (cont)
+(defun mml1991-pgg-sign (_cont)
   (let ((pgg-text-mode t)
         (pgg-default-user-id (or (message-options-get 'mml-sender)
                                  pgg-default-user-id))
@@ -209,7 +210,7 @@ Whether the passphrase is cached at all is controlled by
        (buffer-string)))
     t))
 
-(defun mml1991-pgg-encrypt (cont &optional sign)
+(defun mml1991-pgg-encrypt (_cont &optional sign)
   (goto-char (point-min))
   (when (re-search-forward "^$" nil t)
     (let ((cte (save-restriction
@@ -257,7 +258,7 @@ Whether the passphrase is cached at all is controlled by
 (autoload 'epg-configuration "epg-config")
 (autoload 'epg-expand-group "epg-config")
 
-(defun mml1991-epg-sign (cont)
+(defun mml1991-epg-sign (_cont)
   (let ((inhibit-redisplay t)
         headers cte)
     ;; Don't sign headers.
diff --git a/lisp/gnus/mml2015.el b/lisp/gnus/mml2015.el
index 53454bf16d8..1af7d10d055 100644
--- a/lisp/gnus/mml2015.el
+++ b/lisp/gnus/mml2015.el
@@ -1,4 +1,4 @@
-;;; mml2015.el --- MIME Security with Pretty Good Privacy (PGP)
+;;; mml2015.el --- MIME Security with Pretty Good Privacy (PGP)  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2000-2021 Free Software Foundation, Inc.
 
@@ -185,7 +185,7 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
       (cadr err)
     (format "%S" (cdr err))))
 
-(defun mml2015-mailcrypt-decrypt (handle ctl)
+(defun mml2015-mailcrypt-decrypt (handle _ctl)
   (catch 'error
     (let (child handles result)
       (unless (setq child (mm-find-part-by-type
@@ -479,6 +479,7 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
 (defvar pgg-default-user-id)
 (defvar pgg-errors-buffer)
 (defvar pgg-output-buffer)
+(defvar pgg-text-mode)
 
 (autoload 'pgg-decrypt-region "pgg")
 (autoload 'pgg-verify-region "pgg")
@@ -486,10 +487,10 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
 (autoload 'pgg-encrypt-region "pgg")
 (autoload 'pgg-parse-armor "pgg-parse")
 
-(defun mml2015-pgg-decrypt (handle ctl)
+(defun mml2015-pgg-decrypt (handle _ctl)
   (catch 'error
     (let ((pgg-errors-buffer mml2015-result-buffer)
-          child handles result decrypt-status)
+          child handles decrypt-status) ;; result
       (unless (setq child (mm-find-part-by-type
                            (cdr handle)
                            "application/octet-stream" nil t))
@@ -751,7 +752,7 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
   (let ((key-image (mml2015-epg-key-image key-id)))
     (if (not key-image)
         ""
-      (condition-case error
+      (condition-case nil
           (let ((result "  "))
             (put-text-property
              1 2 'display
@@ -770,10 +771,10 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
 (defun mml2015-epg-verify-result-to-string (verify-result)
   (mapconcat #'mml2015-epg-signature-to-string verify-result "\n"))
 
-(defun mml2015-epg-decrypt (handle ctl)
+(defun mml2015-epg-decrypt (handle _ctl)
   (catch 'error
     (let ((inhibit-redisplay t)
-          context plain child handles result decrypt-status)
+          context plain child handles) ;; decrypt-status result
       (unless (setq child (mm-find-part-by-type
                            (cdr handle)
                            "application/octet-stream" nil t))
@@ -851,7 +852,7 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
 (defun mml2015-epg-verify (handle ctl)
   (catch 'error
     (let ((inhibit-redisplay t)
-          context plain signature-file part signature)
+          context part signature) ;; plain signature-file
       (when (or (null (setq part (mm-find-raw-part-by-type
                                   ctl (or (mm-handle-multipart-ctl-parameter
                                            ctl 'protocol)
@@ -866,7 +867,8 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
             signature (mm-get-part signature)
             context (epg-make-context))
       (condition-case error
-          (setq plain (epg-verify-string context signature part))
+          ;; (setq plain
+          (epg-verify-string context signature part) ;;)
         (error
          (mm-sec-error 'gnus-info "Failed")
          (mm-sec-status 'gnus-details (if (eq (car error) 'quit)
@@ -978,7 +980,7 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
       handle)))
 
 ;;;###autoload
-(defun mml2015-decrypt-test (handle ctl)
+(defun mml2015-decrypt-test (_handle _ctl)
   mml2015-use)
 
 ;;;###autoload
@@ -990,7 +992,7 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
       handle)))
 
 ;;;###autoload
-(defun mml2015-verify-test (handle ctl)
+(defun mml2015-verify-test (_handle _ctl)
   mml2015-use)
 
 ;;;###autoload
diff --git a/lisp/gnus/nnagent.el b/lisp/gnus/nnagent.el
index 1f21eee8680..76a7e21567a 100644
--- a/lisp/gnus/nnagent.el
+++ b/lisp/gnus/nnagent.el
@@ -1,4 +1,4 @@
-;;; nnagent.el --- offline backend for Gnus
+;;; nnagent.el --- offline backend for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1997-2021 Free Software Foundation, Inc.
 
@@ -86,7 +86,7 @@
                        server dir)
       t))))
 
-(deffoo nnagent-retrieve-groups (groups &optional server)
+(deffoo nnagent-retrieve-groups (_groups &optional _server)
   (save-excursion
     (cond
      ((file-exists-p (gnus-agent-lib-file "groups"))
@@ -106,13 +106,13 @@
         (funcall (gnus-get-function gnus-command-method 'request-type)
                  (gnus-group-real-name group) article)))))
 
-(deffoo nnagent-request-newgroups (date server)
+(deffoo nnagent-request-newgroups (_date _server)
   nil)
 
-(deffoo nnagent-request-update-info (group info &optional server)
+(deffoo nnagent-request-update-info (_group _info &optional _server)
   nil)
 
-(deffoo nnagent-request-post (&optional server)
+(deffoo nnagent-request-post (&optional _server)
   (gnus-agent-insert-meta-information 'news gnus-command-method)
   (gnus-request-accept-article "nndraft:queue" nil t t))
 
@@ -184,7 +184,7 @@
         t)
       'nov)))
 
-(deffoo nnagent-request-expire-articles (articles group &optional server force)
+(deffoo nnagent-request-expire-articles (articles _group &optional _server _force)
   articles)
 
 (deffoo nnagent-request-group (group &optional server dont-check info)
@@ -249,7 +249,7 @@
   (nnoo-parent-function 'nnagent 'nnml-request-regenerate
                         (list (nnagent-server server))))
 
-(deffoo nnagent-retrieve-group-data-early (server infos)
+(deffoo nnagent-retrieve-group-data-early (_server _infos)
   nil)
 
 ;; Use nnml functions for just about everything.
diff --git a/lisp/gnus/nnbabyl.el b/lisp/gnus/nnbabyl.el
index 41f7f62fae6..3e6f9e88eea 100644
--- a/lisp/gnus/nnbabyl.el
+++ b/lisp/gnus/nnbabyl.el
@@ -1,4 +1,4 @@
-;;; nnbabyl.el --- rmail mbox access for Gnus
+;;; nnbabyl.el --- rmail mbox access for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -70,7 +70,7 @@
 
 (nnoo-define-basics nnbabyl)
 
-(deffoo nnbabyl-retrieve-headers (articles &optional group server fetch-old)
+(deffoo nnbabyl-retrieve-headers (articles &optional group server _fetch-old)
   (with-current-buffer nntp-server-buffer
     (erase-buffer)
     (let ((number (length articles))
@@ -185,7 +185,7 @@
               (cons nnbabyl-current-group article)
             (nnbabyl-article-group-number)))))))
 
-(deffoo nnbabyl-request-group (group &optional server dont-check info)
+(deffoo nnbabyl-request-group (group &optional server dont-check _info)
   (let ((active (cadr (assoc group nnbabyl-group-alist))))
     (save-excursion
       (cond
@@ -224,10 +224,10 @@
          (insert-buffer-substring in-buf)))
      (nnmail-save-active nnbabyl-group-alist nnbabyl-active-file))))
 
-(deffoo nnbabyl-close-group (group &optional server)
+(deffoo nnbabyl-close-group (_group &optional _server)
   t)
 
-(deffoo nnbabyl-request-create-group (group &optional server args)
+(deffoo nnbabyl-request-create-group (group &optional _server _args)
   (nnmail-activate 'nnbabyl)
   (unless (assoc group nnbabyl-group-alist)
     (push (list group (cons 1 0))
@@ -235,18 +235,20 @@
     (nnmail-save-active nnbabyl-group-alist nnbabyl-active-file))
   t)
 
-(deffoo nnbabyl-request-list (&optional server)
+(deffoo nnbabyl-request-list (&optional _server)
   (save-excursion
     (nnmail-find-file nnbabyl-active-file)
     (setq nnbabyl-group-alist (nnmail-get-active))
     t))
 
-(deffoo nnbabyl-request-newgroups (date &optional server)
+(deffoo nnbabyl-request-newgroups (_date &optional server)
   (nnbabyl-request-list server))
 
-(deffoo nnbabyl-request-list-newsgroups (&optional server)
+(deffoo nnbabyl-request-list-newsgroups (&optional _server)
   (nnheader-report 'nnbabyl "nnbabyl: LIST NEWSGROUPS is not implemented."))
 
+(defvar nnml-current-directory)
+
 (deffoo nnbabyl-request-expire-articles
     (articles newsgroup &optional server force)
   (nnbabyl-possibly-change-newsgroup newsgroup server)
@@ -293,7 +295,7 @@
       (nconc rest articles))))
 
 (deffoo nnbabyl-request-move-article
-    (article group server accept-form &optional last move-is-internal)
+    (article group server accept-form &optional last _move-is-internal)
   (let ((buf (gnus-get-buffer-create " *nnbabyl move*"))
         result)
     (and
@@ -305,7 +307,7 @@
                "^X-Gnus-Newsgroup:"
                (save-excursion (search-forward "\n\n" nil t) (point)) t)
          (delete-region (point-at-bol) (progn (forward-line 1) (point))))
-       (setq result (eval accept-form))
+       (setq result (eval accept-form t))
        (kill-buffer (current-buffer))
        result)
      (save-excursion
diff --git a/lisp/gnus/nndiary.el b/lisp/gnus/nndiary.el
index 60ef6e9b8ed..15003fabcd2 100644
--- a/lisp/gnus/nndiary.el
+++ b/lisp/gnus/nndiary.el
@@ -1,4 +1,4 @@
-;;; nndiary.el --- A diary back end for Gnus
+;;; nndiary.el --- A diary back end for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1999-2021 Free Software Foundation, Inc.
 
@@ -469,7 +469,7 @@ all.  This may very well take some time.")
       (cons (if group-num (car group-num) group)
             (string-to-number (file-name-nondirectory path)))))))
 
-(deffoo nndiary-request-group (group &optional server dont-check info)
+(deffoo nndiary-request-group (group &optional server dont-check _info)
   (let ((file-name-coding-system nnmail-pathname-coding-system))
     (cond
      ((not (nndiary-possibly-change-directory group server))
@@ -503,11 +503,11 @@ all.  This may very well take some time.")
     (nndiary-possibly-change-directory group server)
     (nnmail-get-new-mail 'nndiary 'nndiary-save-nov nndiary-directory group)))
 
-(deffoo nndiary-close-group (group &optional server)
+(deffoo nndiary-close-group (_group &optional _server)
   (setq nndiary-article-file-alist nil)
   t)
 
-(deffoo nndiary-request-create-group (group &optional server args)
+(deffoo nndiary-request-create-group (group &optional server _args)
   (nndiary-possibly-change-directory nil server)
   (nnmail-activate 'nndiary)
   (cond
@@ -535,7 +535,7 @@ all.  This may very well take some time.")
       t))
    ))
 
-(deffoo nndiary-request-list (&optional server)
+(deffoo nndiary-request-list (&optional _server)
   (save-excursion
     (let ((nnmail-file-coding-system nnmail-active-file-coding-system)
           (file-name-coding-system nnmail-pathname-coding-system))
@@ -543,10 +543,10 @@ all.  This may very well take some time.")
     (setq nndiary-group-alist (nnmail-get-active))
     t))
 
-(deffoo nndiary-request-newgroups (date &optional server)
+(deffoo nndiary-request-newgroups (_date &optional server)
   (nndiary-request-list server))
 
-(deffoo nndiary-request-list-newsgroups (&optional server)
+(deffoo nndiary-request-list-newsgroups (&optional _server)
   (save-excursion
     (nnmail-find-file nndiary-newsgroups-file)))
 
@@ -590,7 +590,7 @@ all.  This may very well take some time.")
     (nconc rest articles)))
 
 (deffoo nndiary-request-move-article
-    (article group server accept-form &optional last move-is-internal)
+    (article group server accept-form &optional last _move-is-internal)
   (let ((buf (gnus-get-buffer-create " *nndiary move*"))
         result)
     (nndiary-possibly-change-directory group server)
@@ -603,7 +603,7 @@ all.  This may very well take some time.")
            nndiary-article-file-alist)
        (with-current-buffer buf
          (insert-buffer-substring nntp-server-buffer)
-         (setq result (eval accept-form))
+         (setq result (eval accept-form t))
          (kill-buffer (current-buffer))
          result))
      (progn
@@ -766,7 +766,7 @@ all.  This may very well take some time.")
 
 ;;; Interface optional functions ============================================
 
-(deffoo nndiary-request-update-info (group info &optional server)
+(deffoo nndiary-request-update-info (group info &optional _server)
   (nndiary-possibly-change-directory group)
   (let ((timestamp (gnus-group-parameter-value (gnus-info-params info)
                                                'timestamp t)))
@@ -1033,6 +1033,8 @@ all.  This may very well take some time.")
   ;; Save the active file.
   (nnmail-save-active nndiary-group-alist nndiary-active-file))
 
+(defvar nndiary-files) ; dynamically bound in nndiary-generate-nov-databases-1
+
 (defun nndiary-generate-nov-databases-1 (dir &optional seen no-active)
   "Regenerate the NOV database in DIR."
   (interactive "DRegenerate NOV in: ")
@@ -1062,7 +1064,6 @@ all.  This may very well take some time.")
         (unless no-active
           (nnmail-save-active nndiary-group-alist nndiary-active-file))))))
 
-(defvar nndiary-files) ; dynamically bound in nndiary-generate-nov-databases-1
 (defun nndiary-generate-active-info (dir)
   ;; Update the active info for this group.
   (let* ((group (nnheader-file-to-group
diff --git a/lisp/gnus/nndir.el b/lisp/gnus/nndir.el
index 46351d0004f..bfc22836583 100644
--- a/lisp/gnus/nndir.el
+++ b/lisp/gnus/nndir.el
@@ -1,4 +1,4 @@
-;;; nndir.el --- single directory newsgroup access for Gnus
+;;; nndir.el --- single directory newsgroup access for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/nndoc.el b/lisp/gnus/nndoc.el
index dccf6c1ffb7..172433ef3b8 100644
--- a/lisp/gnus/nndoc.el
+++ b/lisp/gnus/nndoc.el
@@ -1,4 +1,4 @@
-;;; nndoc.el --- single file access for Gnus
+;;; nndoc.el --- single file access for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -225,7 +225,7 @@ from the document.")
 
 (nnoo-define-basics nndoc)
 
-(deffoo nndoc-retrieve-headers (articles &optional newsgroup server fetch-old)
+(deffoo nndoc-retrieve-headers (articles &optional newsgroup server _fetch-old)
   (when (nndoc-possibly-change-buffer newsgroup server)
     (with-current-buffer nntp-server-buffer
       (erase-buffer)
@@ -280,7 +280,7 @@ from the document.")
             (funcall nndoc-article-transform-function article))
           t))))))
 
-(deffoo nndoc-request-group (group &optional server dont-check info)
+(deffoo nndoc-request-group (group &optional server dont-check _info)
   "Select news GROUP."
   (let (number)
     (cond
@@ -301,7 +301,7 @@ from the document.")
     (nndoc-request-group group server))
   t)
 
-(deffoo nndoc-request-type (group &optional article)
+(deffoo nndoc-request-type (_group &optional article)
   (cond ((not article) 'unknown)
         (nndoc-post-type nndoc-post-type)
         (t 'unknown)))
@@ -317,19 +317,19 @@ from the document.")
   (setq nndoc-dissection-alist nil)
   t)
 
-(deffoo nndoc-request-list (&optional server)
+(deffoo nndoc-request-list (&optional _server)
   t)
 
-(deffoo nndoc-request-newgroups (date &optional server)
+(deffoo nndoc-request-newgroups (_date &optional _server)
   nil)
 
-(deffoo nndoc-request-list-newsgroups (&optional server)
+(deffoo nndoc-request-list-newsgroups (&optional _server)
   nil)
 
 
 ;;; Internal functions.
 
-(defun nndoc-possibly-change-buffer (group source)
+(defun nndoc-possibly-change-buffer (group _source)
   (let (buf)
     (cond
      ;; The current buffer is this group's buffer.
@@ -677,7 +677,7 @@ from the document.")
        (search-forward "\ncommit " nil t)
        (search-forward "\nAuthor: " nil t)))
 
-(defun nndoc-transform-git-article (article)
+(defun nndoc-transform-git-article (_article)
   (goto-char (point-min))
   (when (re-search-forward "^Author: " nil t)
     (replace-match "From: " t t)))
@@ -701,7 +701,7 @@ from the document.")
           (re-search-forward "^\\\\\\\\\n\\(Paper\\( (\\*cross-listing\\*)\\)?: [a-zA-Z\\.-]+/[0-9]+\\|arXiv:\\)" nil t))
     t))
 
-(defun nndoc-transform-lanl-gov-announce (article)
+(defun nndoc-transform-lanl-gov-announce (_article)
   (let ((case-fold-search nil))
     (goto-char (point-max))
     (when (re-search-backward "^\\\\\\\\ +( *\\([^ ]*\\) , *\\([^ ]*\\))" nil t)
@@ -858,7 +858,7 @@ from the document.")
           nil)
         (goto-char point))))
 
-(deffoo nndoc-request-accept-article (group &optional server last)
+(deffoo nndoc-request-accept-article (_group &optional _server _last)
   nil)
 
 ;;;
diff --git a/lisp/gnus/nndraft.el b/lisp/gnus/nndraft.el
index e636636a174..394b6fcc4fc 100644
--- a/lisp/gnus/nndraft.el
+++ b/lisp/gnus/nndraft.el
@@ -1,4 +1,4 @@
-;;; nndraft.el --- draft article access for Gnus
+;;; nndraft.el --- draft article access for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -79,7 +79,7 @@ are generated if and only if they are also in `message-draft-headers'."
                      server nndraft-directory)
     t)))
 
-(deffoo nndraft-retrieve-headers (articles &optional group server fetch-old)
+(deffoo nndraft-retrieve-headers (articles &optional group server _fetch-old)
   (nndraft-possibly-change-group group)
   (with-current-buffer nntp-server-buffer
     (erase-buffer)
@@ -108,7 +108,7 @@ are generated if and only if they are also in `message-draft-headers'."
         (nnheader-fold-continuation-lines)
         'headers))))
 
-(deffoo nndraft-request-article (id &optional group server buffer)
+(deffoo nndraft-request-article (id &optional group _server buffer)
   (nndraft-possibly-change-group group)
   (when (numberp id)
     ;; We get the newest file of the auto-saved file and the
@@ -145,7 +145,7 @@ are generated if and only if they are also in `message-draft-headers'."
     ;;(message-remove-header "date")
     t))
 
-(deffoo nndraft-request-update-info (group info &optional server)
+(deffoo nndraft-request-update-info (group info &optional _server)
   (nndraft-possibly-change-group group)
   (setf (gnus-info-read info)
         (gnus-update-read-articles
@@ -210,7 +210,7 @@ are generated if and only if they are also in `message-draft-headers'."
                         'exit 'postpone 'kill)
     article))
 
-(deffoo nndraft-request-group (group &optional server dont-check info)
+(deffoo nndraft-request-group (group &optional server dont-check _info)
   (nndraft-possibly-change-group group)
   (unless dont-check
     (let* ((pathname (nnmail-group-pathname group nndraft-directory))
@@ -229,7 +229,7 @@ are generated if and only if they are also in `message-draft-headers'."
                         (list group server dont-check)))
 
 (deffoo nndraft-request-move-article (article group server accept-form
-                                      &optional last move-is-internal)
+                                      &optional _last _move-is-internal)
   (nndraft-possibly-change-group group)
   (let ((buf (gnus-get-buffer-create " *nndraft move*"))
         result)
@@ -238,7 +238,7 @@ are generated if and only if they are also in `message-draft-headers'."
      (with-current-buffer buf
        (erase-buffer)
        (insert-buffer-substring nntp-server-buffer)
-       (setq result (eval accept-form))
+       (setq result (eval accept-form t))
        (kill-buffer (current-buffer))
        result)
      (null (nndraft-request-expire-articles (list article) group server 'force))
@@ -292,7 +292,7 @@ are generated if and only if they are also in `message-draft-headers'."
     (nnoo-parent-function 'nndraft 'nnmh-request-replace-article
                           (list article group buffer))))
 
-(deffoo nndraft-request-create-group (group &optional server args)
+(deffoo nndraft-request-create-group (group &optional _server _args)
   (nndraft-possibly-change-group group)
   (if (file-exists-p nndraft-current-directory)
       (if (file-directory-p nndraft-current-directory)
diff --git a/lisp/gnus/nneething.el b/lisp/gnus/nneething.el
index 014ad3adfb1..d881d6ce055 100644
--- a/lisp/gnus/nneething.el
+++ b/lisp/gnus/nneething.el
@@ -1,4 +1,4 @@
-;;; nneething.el --- arbitrary file access for Gnus
+;;; nneething.el --- arbitrary file access for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -77,7 +77,7 @@ included.")
 
 (nnoo-define-basics nneething)
 
-(deffoo nneething-retrieve-headers (articles &optional group server fetch-old)
+(deffoo nneething-retrieve-headers (articles &optional group _server _fetch-old)
   (nneething-possibly-change-directory group)
 
   (with-current-buffer nntp-server-buffer
@@ -114,7 +114,7 @@ included.")
         (nnheader-fold-continuation-lines)
         'headers))))
 
-(deffoo nneething-request-article (id &optional group server buffer)
+(deffoo nneething-request-article (id &optional group _server buffer)
   (nneething-possibly-change-directory group)
   (let ((file (unless (stringp id)
                 (nneething-file-name id)))
@@ -143,7 +143,7 @@ included.")
              (insert "\n"))
            t))))
 
-(deffoo nneething-request-group (group &optional server dont-check info)
+(deffoo nneething-request-group (group &optional server dont-check _info)
   (nneething-possibly-change-directory group server)
   (unless dont-check
     (nneething-create-mapping)
@@ -156,16 +156,16 @@ included.")
        group)))
   t)
 
-(deffoo nneething-request-list (&optional server dir)
+(deffoo nneething-request-list (&optional _server _dir)
   (nnheader-report 'nneething "LIST is not implemented."))
 
-(deffoo nneething-request-newgroups (date &optional server)
+(deffoo nneething-request-newgroups (_date &optional _server)
   (nnheader-report 'nneething "NEWSGROUPS is not implemented."))
 
-(deffoo nneething-request-type (group &optional article)
+(deffoo nneething-request-type (_group &optional _article)
   'unknown)
 
-(deffoo nneething-close-group (group &optional server)
+(deffoo nneething-close-group (_group &optional _server)
   (setq nneething-current-directory nil)
   t)
 
diff --git a/lisp/gnus/nnfolder.el b/lisp/gnus/nnfolder.el
index 70e15c57130..1dd784d5a5b 100644
--- a/lisp/gnus/nnfolder.el
+++ b/lisp/gnus/nnfolder.el
@@ -1,4 +1,4 @@
-;;; nnfolder.el --- mail folder access for Gnus
+;;; nnfolder.el --- mail folder access for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -261,7 +261,7 @@ all.  This may very well take some time.")
                                       (point) (point-at-eol)))
                     -1))))))))
 
-(deffoo nnfolder-request-group (group &optional server dont-check info)
+(deffoo nnfolder-request-group (group &optional server dont-check _info)
   (nnfolder-possibly-change-group group server t)
   (save-excursion
     (cond ((not (assoc group nnfolder-group-alist))
@@ -314,7 +314,7 @@ all.  This may very well take some time.")
 ;; over the buffer again unless we add new mail to it or modify it in some
 ;; way.
 
-(deffoo nnfolder-close-group (group &optional server force)
+(deffoo nnfolder-close-group (group &optional _server _force)
   ;; Make sure we _had_ the group open.
   (when (or (assoc group nnfolder-buffer-alist)
             (equal group nnfolder-current-group))
@@ -342,7 +342,7 @@ all.  This may very well take some time.")
         nnfolder-current-buffer nil)
   t)
 
-(deffoo nnfolder-request-create-group (group &optional server args)
+(deffoo nnfolder-request-create-group (group &optional server _args)
   (nnfolder-possibly-change-group nil server)
   (nnmail-activate 'nnfolder)
   (cond ((zerop (length group))
@@ -369,7 +369,7 @@ all.  This may very well take some time.")
       (setq nnfolder-group-alist (nnmail-get-active)))
     t))
 
-(deffoo nnfolder-request-newgroups (date &optional server)
+(deffoo nnfolder-request-newgroups (_date &optional server)
   (nnfolder-possibly-change-group nil server)
   (nnfolder-request-list server))
 
@@ -394,12 +394,13 @@ all.  This may very well take some time.")
           (let ((newnum (string-to-number (match-string 0))))
             (if (nnmail-within-headers-p)
                 (push newnum numbers))))
-      ;; The article numbers are increasing, so this result is sorted.
+        ;; The article numbers are increasing, so this result is sorted.
         (nreverse numbers)))))
 
 (autoload 'gnus-request-group "gnus-int")
 (declare-function gnus-request-create-group "gnus-int"
                   (group &optional gnus-command-method args))
+(defvar nnfolder-current-directory)
 
 (deffoo nnfolder-request-expire-articles (articles newsgroup
                                                    &optional server force)
@@ -462,7 +463,7 @@ all.  This may very well take some time.")
       (gnus-sorted-difference articles (nreverse deleted-articles)))))
 
 (deffoo nnfolder-request-move-article (article group server accept-form
-                                               &optional last move-is-internal)
+                                               &optional last _move-is-internal)
   (save-excursion
     (let ((buf (gnus-get-buffer-create " *nnfolder move*"))
           result)
@@ -477,7 +478,7 @@ all.  This may very well take some time.")
                  (save-excursion (and (search-forward "\n\n" nil t) (point)))
                  t)
            (gnus-delete-line))
-         (setq result (eval accept-form))
+         (setq result (eval accept-form t))
          (kill-buffer buf)
          result)
        (save-excursion
@@ -498,7 +499,7 @@ all.  This may very well take some time.")
   (save-excursion
     (nnfolder-possibly-change-group group server)
     (nnmail-check-syntax)
-    (let ((buf (current-buffer))
+    (let (;; (buf (current-buffer))
           result art-group)
       (goto-char (point-min))
       (when (looking-at "X-From-Line: ")
diff --git a/lisp/gnus/nngateway.el b/lisp/gnus/nngateway.el
index 15e4876642c..c10989aa1e9 100644
--- a/lisp/gnus/nngateway.el
+++ b/lisp/gnus/nngateway.el
@@ -1,4 +1,4 @@
-;;; nngateway.el --- posting news via mail gateways
+;;; nngateway.el --- posting news via mail gateways  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/nnheader.el b/lisp/gnus/nnheader.el
index ae8506c5c20..708887cb9c7 100644
--- a/lisp/gnus/nnheader.el
+++ b/lisp/gnus/nnheader.el
@@ -1,4 +1,4 @@
-;;; nnheader.el --- header access macros for Gnus and its backends
+;;; nnheader.el --- header access macros for Gnus and its backends  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1987-1990, 1993-1998, 2000-2021 Free Software
 ;; Foundation, Inc.
diff --git a/lisp/gnus/nnimap.el b/lisp/gnus/nnimap.el
index 4a50f1127b9..f4f4ef89a9e 100644
--- a/lisp/gnus/nnimap.el
+++ b/lisp/gnus/nnimap.el
@@ -1,4 +1,4 @@
-;;; nnimap.el --- IMAP interface for Gnus
+;;; nnimap.el --- IMAP interface for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2010-2021 Free Software Foundation, Inc.
 
@@ -1004,7 +1004,7 @@ during splitting, which may be slow."
                            internal-move-group server message-id
                            nnimap-request-articles-find-limit)))))
           ;; Move the article to a different method.
-          (when-let* ((result (eval accept-form)))
+          (when-let* ((result (eval accept-form t)))
             (nnimap-change-group group server)
             (nnimap-delete-article article)
             result))))))
@@ -1165,7 +1165,7 @@ If LIMIT, first try to limit the search to the N last articles."
        7 "Article marked for deletion, but not expunged.")
       nil))))
 
-(deffoo nnimap-request-scan (&optional group server)
+(deffoo nnimap-request-scan (&optional _group server)
   (when (and (nnimap-change-group nil server)
              nnimap-inbox
              nnimap-split-methods)
diff --git a/lisp/gnus/nnmail.el b/lisp/gnus/nnmail.el
index 251ae657bbf..ac56e8f4b9b 100644
--- a/lisp/gnus/nnmail.el
+++ b/lisp/gnus/nnmail.el
@@ -1,4 +1,4 @@
-;;; nnmail.el --- mail support functions for the Gnus mail backends
+;;; nnmail.el --- mail support functions for the Gnus mail backends  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -598,7 +598,7 @@ These will be logged to the \"*nnmail split*\" buffer."
 
 
 
-(defun nnmail-request-post (&optional server)
+(defun nnmail-request-post (&optional _server)
   (mail-send-and-exit nil))
 
 (defvar nnmail-file-coding-system 'raw-text
@@ -664,7 +664,7 @@ nn*-request-list should have been called before calling this function."
   (let ((buffer (current-buffer))
         group-assoc group max min)
     (while (not (eobp))
-      (condition-case err
+      (condition-case nil
           (progn
             (narrow-to-region (point) (point-at-eol))
             (setq group (read buffer)
@@ -1332,7 +1332,7 @@ Eudora has a broken References line, but an OK In-Reply-To."
 (declare-function gnus-activate-group "gnus-start"
                   (group &optional scan dont-check method dont-sub-check))
 
-(defun nnmail-do-request-post (accept-func &optional server)
+(defun nnmail-do-request-post (accept-func &optional _server)
   "Utility function to directly post a message to an nnmail-derived group.
 Calls ACCEPT-FUNC (which should be `nnchoke-request-accept-article')
 to actually put the message in the right group."
@@ -1397,7 +1397,7 @@ See the documentation for the variable `nnmail-split-fancy' for details."
      ;; Builtin : operation.
      ((eq (car split) ':)
       (nnmail-log-split split)
-      (nnmail-split-it (save-excursion (eval (cdr split)))))
+      (nnmail-split-it (save-excursion (eval (cdr split) t))))
 
      ;; Builtin ! operation.
      ((eq (car split) '!)
@@ -1783,7 +1783,7 @@ be called once per group or once for all groups."
       (assq 'directory mail-sources)))
 
 (defun nnmail-get-new-mail-1 (method exit-func temp
-                              group in-group spool-func)
+                              group _in-group spool-func)
   (let* ((sources mail-sources)
          fetching-sources
          (i 0)
@@ -1918,7 +1918,7 @@ If TIME is nil, then return the cutoff time for oldness instead."
                      (cdr group-art))
             (gnus-group-mark-article-read target (cdr group-art))))))))
 
-(defun nnmail-fancy-expiry-target (group)
+(defun nnmail-fancy-expiry-target (_group)
   "Return a target expiry group determined by `nnmail-fancy-expiry-targets'."
   (let* (header
          (case-fold-search nil)
diff --git a/lisp/gnus/nnmairix.el b/lisp/gnus/nnmairix.el
index 8b3ab40e225..a2de5e061e0 100644
--- a/lisp/gnus/nnmairix.el
+++ b/lisp/gnus/nnmairix.el
@@ -1,4 +1,4 @@
-;;; nnmairix.el --- Mairix back end for Gnus, the Emacs newsreader
+;;; nnmairix.el --- Mairix back end for Gnus, the Emacs newsreader  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2007-2021 Free Software Foundation, Inc.
 
@@ -404,7 +404,7 @@ Other back ends might or might not work.")
   (setq nnmairix-current-server server)
   (nnoo-change-server 'nnmairix server definitions))
 
-(deffoo nnmairix-request-group (group &optional server fast info)
+(deffoo nnmairix-request-group (group &optional server fast _info)
   ;; Call mairix and request group on back end server
   (when server (nnmairix-open-server server))
   (let* ((qualgroup (if server
@@ -417,7 +417,7 @@ Other back ends might or might not work.")
          (backendmethod (gnus-server-to-method
                          (format "%s:%s" (symbol-name nnmairix-backend)
                                  nnmairix-backend-server)))
-         rval mfolder folderpath args)
+         rval mfolder folderpath) ;; args
     (cond
      ((not folder)
       ;; No folder parameter -> error
@@ -497,12 +497,12 @@ Other back ends might or might not work.")
         nil))))))
 
 
-(deffoo nnmairix-request-create-group (group &optional server args)
+(deffoo nnmairix-request-create-group (group &optional server _args)
   (let ((qualgroup (if server (gnus-group-prefixed-name group (list 'nnmairix server))
                      group))
         (exist t)
         (count 0)
-        groupname info)
+        groupname) ;; info
     (when server (nnmairix-open-server server))
     (gnus-group-add-parameter qualgroup '(query . nil))
     (gnus-group-add-parameter qualgroup '(threads . nil))
@@ -561,7 +561,7 @@ Other back ends might or might not work.")
 (deffoo nnmairix-request-list (&optional server)
   (when server (nnmairix-open-server server))
   (if (nnmairix-call-backend "request-list" nnmairix-backend-server)
-      (let (cpoint cur qualgroup folder)
+      (let (cpoint cur qualgroup) ;; folder
         (with-current-buffer nntp-server-buffer
           (goto-char (point-min))
           (setq cpoint (point))
@@ -590,7 +590,7 @@ Other back ends might or might not work.")
     (nnmairix-open-server server))
   (let* ((qualgroup (gnus-group-prefixed-name group (list 'nnmairix nnmairix-current-server)))
          (propmarks (gnus-group-get-parameter qualgroup 'propmarks))
-         (propto (gnus-group-get-parameter qualgroup 'propto t))
+         ;; (propto (gnus-group-get-parameter qualgroup 'propto t))
          (corr (nnmairix-get-numcorr group server))
          (folder (nnmairix-get-backend-folder group server)))
     (save-excursion
@@ -598,7 +598,7 @@ Other back ends might or might not work.")
         (let ((type (nth 1 cur))
               (cmdmarks (nth 2 cur))
               (range (gnus-uncompress-range (nth 0 cur)))
-              mid ogroup number method temp)
+              mid ogroup temp) ;; number method
           (when (and corr
                      (not (zerop (cadr corr))))
             (setq range (mapcar (lambda (arg)
@@ -661,7 +661,7 @@ Other back ends might or might not work.")
     (nnmairix-open-server server))
   (let* ((qualgroup (gnus-group-prefixed-name group (list 'nnmairix nnmairix-current-server)))
          (propmarks (gnus-group-get-parameter qualgroup 'propmarks))
-         method)
+         ) ;; method
     (when (and propmarks
                nnmairix-marks-cache)
       (when (or (eq nnmairix-propagate-marks-upon-close t)
@@ -690,7 +690,7 @@ Other back ends might or might not work.")
          (corr (nnmairix-get-numcorr group server))
          (docorr (and corr (not (zerop (cadr corr)))))
          (folderinfo `(,group 1 ((1 . 1))))
-         readrange marks)
+         ) ;; readrange marks
       (when (and propmarks
                  nnmairix-propagate-marks-to-nnmairix-groups)
         ;; these groups are not subscribed, so we have to ask the back end directly
@@ -778,7 +778,7 @@ called interactively, user will be asked for parameters."
   (interactive)
   (let ((char-header nnmairix-interactive-query-parameters)
         (server (nnmairix-backend-to-server gnus-current-select-method))
-         query achar header finished group threads cq)
+         query achar header finished group threads) ;; cq
     (when (or (not (gnus-buffer-live-p gnus-article-buffer))
               (not (gnus-buffer-live-p gnus-summary-buffer)))
       (error "No article or summary buffer"))
@@ -796,7 +796,8 @@ called interactively, user will be asked for parameters."
             (setq achar nil)))
         (set-buffer gnus-article-buffer)
         (setq header nil)
-        (when (setq cq (nth 1 (assoc achar char-header)))
+        (when ;; (setq cq
+            (nth 1 (assoc achar char-header)) ;;)
           (setq header
                 (nnmairix-replace-illegal-chars
                  (gnus-fetch-field (nth 1 (assoc achar char-header))))))
@@ -827,7 +828,7 @@ All necessary information will be queried from the user."
         (hidden (and (string-match "^nn\\(imap\\|maildir\\)$" backend)
                      (y-or-n-p
                       "Does the back end server work with maildir++ (i.e. hidden directories)? ")))
-        create)
+        ) ;; create
 
     (apply (intern (format "%s-%s" backend "open-server"))
            (list servername))
@@ -1009,7 +1010,7 @@ before deleting a group on the back end.  SERVER specifies nnmairix server."
     (if (nnmairix-open-server (nth 1 server))
         (when (nnmairix-call-backend
                "request-list" nnmairix-backend-server)
-          (let (cur qualgroup folder)
+          (let (cur qualgroup) ;; folder
             (with-current-buffer nntp-server-buffer
               (goto-char (point-min))
               (while (re-search-forward nnmairix-group-regexp (point-max) t)
@@ -1172,7 +1173,7 @@ Marks propagation has to be enabled for this to work."
     (error "Not in a nnmairix group"))
   (save-excursion
     (let ((mid (mail-header-message-id (gnus-summary-article-header)))
-          groups cur)
+          groups) ;; cur
       (when mid
         (setq groups (nnmairix-determine-original-group-from-registry mid))
         (unless (or groups
@@ -1299,7 +1300,7 @@ If ALL is t, return also the unopened/failed ones."
   "Return list of valid back end servers for nnmairix groups."
   (let ((alist gnus-opened-servers)
         (mairixservers (nnmairix-get-nnmairix-servers t))
-        server mserver openedserver occ cur)
+        server mserver openedserver occ) ;; cur
     ;; Get list of all nnmairix backends (i.e. backends which are
     ;; already occupied)
     (dolist (cur mairixservers)
@@ -1393,7 +1394,7 @@ TYPE is either `nov' or `headers'."
     (let ((buf (gnus-get-buffer-create " *nnmairix buffer*"))
           (corr (not (zerop numc)))
           (name (buffer-name nntp-server-buffer))
-          header cur xref)
+          cur xref) ;; header
       (with-current-buffer buf
         (erase-buffer)
         (set-buffer nntp-server-buffer)
@@ -1586,7 +1587,7 @@ search in raw mode."
   (when (not (gnus-buffer-live-p gnus-article-buffer))
     (error "No article buffer available"))
   (let ((server (nth 1 gnus-current-select-method))
-        mid rval group allgroups)
+        mid group allgroups) ;; rval
     ;; get message id
     (with-current-buffer gnus-article-buffer
       (gnus-summary-toggle-header 1)
@@ -1817,10 +1818,10 @@ MVALUES may contain values from current article."
   (widget-create 'push-button
                  :notify
                  (if mvalues
-                     (lambda (&rest ignore)
+                     (lambda (&rest _ignore)
                        (nnmairix-widget-send-query nnmairix-widgets
                                                    t))
-                   (lambda (&rest ignore)
+                   (lambda (&rest _ignore)
                      (nnmairix-widget-send-query nnmairix-widgets
                                                  nil)))
                  "Send Query")
@@ -1828,16 +1829,16 @@ MVALUES may contain values from current article."
   (widget-create 'push-button
                  :notify
                  (if mvalues
-                     (lambda (&rest ignore)
+                     (lambda (&rest _ignore)
                        (nnmairix-widget-create-group nnmairix-widgets
                                                      t))
-                   (lambda (&rest ignore)
+                   (lambda (&rest _ignore)
                      (nnmairix-widget-create-group nnmairix-widgets
                                                    nil)))
                  "Create permanent group")
   (widget-insert "   ")
   (widget-create 'push-button
-                 :notify (lambda (&rest ignore)
+                 :notify (lambda (&rest _ignore)
                            (kill-buffer nnmairix-customize-query-buffer))
                  "Cancel")
   (use-local-map widget-keymap)
@@ -1912,7 +1913,7 @@ If WITHVALUES is t, query is based on current article."
 (defun nnmairix-widget-create-query (&optional values)
   "Create widgets for creating mairix queries.
 Fill in VALUES if based on an article."
-  (let (allwidgets)
+  ;;(let (allwidgets)
     (when (get-buffer nnmairix-customize-query-buffer)
       (kill-buffer nnmairix-customize-query-buffer))
     (switch-to-buffer nnmairix-customize-query-buffer)
@@ -1943,7 +1944,7 @@ Fill in VALUES if based on an article."
     (when (member 'threads nnmairix-widget-other)
       (widget-insert "\n")
       (nnmairix-widget-add "Threads" 'checkbox nil))
-      (widget-insert " Show full threads\n\n")))
+      (widget-insert " Show full threads\n\n")) ;; )
 
 (defun nnmairix-widget-build-editable-fields (values)
   "Build editable field widgets in `nnmairix-widget-fields-list'.
@@ -1960,7 +1961,7 @@ VALUES may contain values for editable fields from current article."
                 (concat "c" field)
                 (widget-create 'checkbox
                                :tag field
-                               :notify (lambda (widget &rest ignore)
+                               :notify (lambda (widget &rest _ignore)
                                          (nnmairix-widget-toggle-activate widget))
                                nil)))
               (list
diff --git a/lisp/gnus/nnmbox.el b/lisp/gnus/nnmbox.el
index 92c7dde9c8f..66c22670b23 100644
--- a/lisp/gnus/nnmbox.el
+++ b/lisp/gnus/nnmbox.el
@@ -1,4 +1,4 @@
-;;; nnmbox.el --- mail mbox access for Gnus
+;;; nnmbox.el --- mail mbox access for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -76,7 +76,7 @@
 
 (nnoo-define-basics nnmbox)
 
-(deffoo nnmbox-retrieve-headers (sequence &optional newsgroup server fetch-old)
+(deffoo nnmbox-retrieve-headers (sequence &optional newsgroup server _fetch-old)
   (with-current-buffer nntp-server-buffer
     (erase-buffer)
     (let ((number (length sequence))
@@ -168,7 +168,7 @@
                 (cons nnmbox-current-group article)
               (nnmbox-article-group-number nil))))))))
 
-(deffoo nnmbox-request-group (group &optional server dont-check info)
+(deffoo nnmbox-request-group (group &optional server dont-check _info)
   (nnmbox-possibly-change-newsgroup nil server)
   (let ((active (cadr (assoc group nnmbox-group-alist))))
     (cond
@@ -213,10 +213,10 @@
          (insert-buffer-substring in-buf)))
      (nnmbox-save-active nnmbox-group-alist nnmbox-active-file))))
 
-(deffoo nnmbox-close-group (group &optional server)
+(deffoo nnmbox-close-group (_group &optional _server)
   t)
 
-(deffoo nnmbox-request-create-group (group &optional server args)
+(deffoo nnmbox-request-create-group (group &optional _server _args)
   (nnmail-activate 'nnmbox)
   (unless (assoc group nnmbox-group-alist)
     (push (list group (cons 1 0))
@@ -224,7 +224,7 @@
     (nnmbox-save-active nnmbox-group-alist nnmbox-active-file))
   t)
 
-(deffoo nnmbox-request-list (&optional server)
+(deffoo nnmbox-request-list (&optional _server)
   (save-excursion
     (let ((nnmail-file-coding-system
            nnmbox-active-file-coding-system))
@@ -232,12 +232,14 @@
     (setq nnmbox-group-alist (nnmail-get-active))
     t))
 
-(deffoo nnmbox-request-newgroups (date &optional server)
+(deffoo nnmbox-request-newgroups (_date &optional server)
   (nnmbox-request-list server))
 
-(deffoo nnmbox-request-list-newsgroups (&optional server)
+(deffoo nnmbox-request-list-newsgroups (&optional _server)
   (nnheader-report 'nnmbox "LIST NEWSGROUPS is not implemented."))
 
+(defvar nnml-current-directory)
+
 (deffoo nnmbox-request-expire-articles
     (articles newsgroup &optional server force)
   (nnmbox-possibly-change-newsgroup newsgroup server)
@@ -278,7 +280,7 @@
       (nconc rest articles))))
 
 (deffoo nnmbox-request-move-article
-    (article group server accept-form &optional last move-is-internal)
+    (article group server accept-form &optional last _move-is-internal)
   (let ((buf (gnus-get-buffer-create " *nnmbox move*"))
         result)
     (and
@@ -291,7 +293,7 @@
                "^X-Gnus-Newsgroup:"
                (save-excursion (search-forward "\n\n" nil t) (point)) t)
          (gnus-delete-line))
-       (setq result (eval accept-form))
+       (setq result (eval accept-form t))
        (kill-buffer buf)
        result)
      (save-excursion
diff --git a/lisp/gnus/nnmh.el b/lisp/gnus/nnmh.el
index 46abf46ce75..231583fae83 100644
--- a/lisp/gnus/nnmh.el
+++ b/lisp/gnus/nnmh.el
@@ -1,4 +1,4 @@
-;;; nnmh.el --- mhspool access for Gnus
+;;; nnmh.el --- mhspool access for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -72,7 +72,7 @@ as unread by Gnus.")
 
 (nnoo-define-basics nnmh)
 
-(deffoo nnmh-retrieve-headers (articles &optional newsgroup server fetch-old)
+(deffoo nnmh-retrieve-headers (articles &optional newsgroup server _fetch-old)
   (with-current-buffer nntp-server-buffer
     (erase-buffer)
     (let* ((file nil)
@@ -147,7 +147,7 @@ as unread by Gnus.")
          (save-excursion (nnmail-find-file file))
          (string-to-number (file-name-nondirectory file)))))
 
-(deffoo nnmh-request-group (group &optional server dont-check info)
+(deffoo nnmh-request-group (group &optional server dont-check _info)
   (nnheader-init-server-buffer)
   (nnmh-possibly-change-directory group server)
   (let ((pathname (nnmail-group-pathname group nnmh-directory))
@@ -188,9 +188,11 @@ as unread by Gnus.")
           (nnheader-report 'nnmh "Empty group %s" group)
           (nnheader-insert (format "211 0 1 0 %s\n" group))))))))))
 
-(deffoo nnmh-request-scan (&optional group server)
+(deffoo nnmh-request-scan (&optional group _server)
   (nnmail-get-new-mail 'nnmh nil nnmh-directory group))
 
+(defvar nnmh-toplev)
+
 (deffoo nnmh-request-list (&optional server dir)
   (nnheader-insert "")
   (nnmh-possibly-change-directory nil server)
@@ -201,13 +203,12 @@ as unread by Gnus.")
   (setq nnmh-group-alist (nnmail-get-active))
   t)
 
-(defvar nnmh-toplev)
 (defun nnmh-request-list-1 (dir)
   (setq dir (expand-file-name dir))
   ;; Recurse down all directories.
   (let ((files (nnheader-directory-files dir t nil t))
         (max 0)
-        min rdir num subdirectoriesp file)
+        min num subdirectoriesp file) ;; rdir
     ;; Recurse down directories.
     (setq subdirectoriesp
           ;; link number always 1 on MS Windows :(
@@ -252,7 +253,7 @@ as unread by Gnus.")
           (or min 1))))))
   t)
 
-(deffoo nnmh-request-newgroups (date &optional server)
+(deffoo nnmh-request-newgroups (_date &optional server)
   (nnmh-request-list server))
 
 (deffoo nnmh-request-expire-articles (articles newsgroup
@@ -291,11 +292,11 @@ as unread by Gnus.")
     (nnheader-message 5 "")
     (nconc rest articles)))
 
-(deffoo nnmh-close-group (group &optional server)
+(deffoo nnmh-close-group (_group &optional _server)
   t)
 
-(deffoo nnmh-request-move-article (article group server accept-form
-                                           &optional last move-is-internal)
+(deffoo nnmh-request-move-article ( article group server accept-form
+                                    &optional _last _move-is-internal)
   (let ((buf (gnus-get-buffer-create " *nnmh move*"))
         result)
     (and
@@ -304,7 +305,7 @@ as unread by Gnus.")
      (with-current-buffer buf
        (erase-buffer)
        (insert-buffer-substring nntp-server-buffer)
-       (setq result (eval accept-form))
+       (setq result (eval accept-form t))
        (kill-buffer (current-buffer))
        result)
      (progn
@@ -350,7 +351,7 @@ as unread by Gnus.")
        nil (if (nnheader-be-verbose 5) nil 'nomesg))
       t)))
 
-(deffoo nnmh-request-create-group (group &optional server args)
+(deffoo nnmh-request-create-group (group &optional server _args)
   (nnheader-init-server-buffer)
   (unless (assoc group nnmh-group-alist)
     (let (active)
diff --git a/lisp/gnus/nnml.el b/lisp/gnus/nnml.el
index eaa2004272f..7bd295399cc 100644
--- a/lisp/gnus/nnml.el
+++ b/lisp/gnus/nnml.el
@@ -1,4 +1,4 @@
-;;; nnml.el --- mail spool access for Gnus
+;;; nnml.el --- mail spool access for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1995-2021 Free Software Foundation, Inc.
 
@@ -111,7 +111,7 @@ non-nil.")
 
 (nnoo-define-basics nnml)
 
-(defun nnml-group-pathname (group &optional file server)
+(defun nnml-group-pathname (group &optional file _server)
   "Return an absolute file name of FILE for GROUP on SERVER."
   (nnmail-group-pathname group nnml-directory file))
 
@@ -215,7 +215,7 @@ non-nil.")
       (cons (if group-num (car group-num) group)
             (string-to-number (file-name-nondirectory path)))))))
 
-(deffoo nnml-request-group (group &optional server dont-check info)
+(deffoo nnml-request-group (group &optional server dont-check _info)
   (let ((file-name-coding-system nnmail-pathname-coding-system))
     (cond
      ((not (nnml-possibly-change-directory group server))
@@ -252,11 +252,11 @@ non-nil.")
    (t
     (nnmail-get-new-mail 'nnml 'nnml-save-incremental-nov nnml-directory nil))))
 
-(deffoo nnml-close-group (group &optional server)
+(deffoo nnml-close-group (_group &optional _server)
   (setq nnml-article-file-alist nil)
   t)
 
-(deffoo nnml-request-create-group (group &optional server args)
+(deffoo nnml-request-create-group (group &optional server _args)
   (nnml-possibly-change-directory nil server)
   (nnmail-activate 'nnml)
   (cond
@@ -283,7 +283,7 @@ non-nil.")
       (nnmail-save-active nnml-group-alist nnml-active-file)
       t))))
 
-(deffoo nnml-request-list (&optional server)
+(deffoo nnml-request-list (&optional _server)
   (save-excursion
     (let ((nnmail-file-coding-system nnmail-active-file-coding-system)
           (file-name-coding-system nnmail-pathname-coding-system))
@@ -291,10 +291,10 @@ non-nil.")
     (setq nnml-group-alist (nnmail-get-active))
     t))
 
-(deffoo nnml-request-newgroups (date &optional server)
+(deffoo nnml-request-newgroups (_date &optional server)
   (nnml-request-list server))
 
-(deffoo nnml-request-list-newsgroups (&optional server)
+(deffoo nnml-request-list-newsgroups (&optional _server)
   (save-excursion
     (nnmail-find-file nnml-newsgroups-file)))
 
@@ -360,7 +360,7 @@ non-nil.")
     (nconc rest articles)))
 
 (deffoo nnml-request-move-article
-    (article group server accept-form &optional last move-is-internal)
+    (article group server accept-form &optional last _move-is-internal)
   (let ((buf (gnus-get-buffer-create " *nnml move*"))
         (file-name-coding-system nnmail-pathname-coding-system)
         result)
@@ -374,7 +374,7 @@ non-nil.")
            nnml-article-file-alist)
        (with-current-buffer buf
          (insert-buffer-substring nntp-server-buffer)
-         (setq result (eval accept-form))
+         (setq result (eval accept-form t))
          (kill-buffer (current-buffer))
          result))
      (progn
@@ -889,7 +889,7 @@ Unless no-active is non-nil, update the active file too."
   (let* ((dir (file-name-as-directory dir))
          (nov (concat dir nnml-nov-file-name))
          (nov-buffer (gnus-get-buffer-create " *nov*"))
-         chars file headers)
+         chars headers) ;; file
     (with-current-buffer nov-buffer
       ;; Init the nov buffer.
       (buffer-disable-undo)
diff --git a/lisp/gnus/nnnil.el b/lisp/gnus/nnnil.el
index 7d400791fa2..36a8bc4581b 100644
--- a/lisp/gnus/nnnil.el
+++ b/lisp/gnus/nnnil.el
@@ -1,4 +1,4 @@
-;;; nnnil.el --- empty backend for Gnus
+;;; nnnil.el --- empty backend for Gnus  -*- lexical-binding: t; -*-
 
 ;; This file is in the public domain.
 
@@ -32,31 +32,31 @@
 
 (defvar nnnil-status-string "")
 
-(defun nnnil-retrieve-headers (articles &optional group server fetch-old)
+(defun nnnil-retrieve-headers (_articles &optional _group _server _fetch-old)
   (with-current-buffer nntp-server-buffer
     (erase-buffer))
   'nov)
 
-(defun nnnil-open-server (server &optional definitions)
+(defun nnnil-open-server (_server &optional _definitions)
   t)
 
-(defun nnnil-close-server (&optional server)
+(defun nnnil-close-server (&optional _server)
   t)
 
 (defun nnnil-request-close ()
   t)
 
-(defun nnnil-server-opened (&optional server)
+(defun nnnil-server-opened (&optional _server)
   t)
 
-(defun nnnil-status-message (&optional server)
+(defun nnnil-status-message (&optional _server)
   nnnil-status-string)
 
-(defun nnnil-request-article (article &optional group server to-buffer)
+(defun nnnil-request-article (_article &optional _group _server _to-buffer)
   (setq nnnil-status-string "No such group")
   nil)
 
-(defun nnnil-request-group (group &optional server fast info)
+(defun nnnil-request-group (_group &optional _server _fast _info)
   (let (deactivate-mark)
     (with-current-buffer nntp-server-buffer
       (erase-buffer)
@@ -64,15 +64,15 @@
   (setq nnnil-status-string "No such group")
   nil)
 
-(defun nnnil-close-group (group &optional server)
+(defun nnnil-close-group (_group &optional _server)
   t)
 
-(defun nnnil-request-list (&optional server)
+(defun nnnil-request-list (&optional _server)
   (with-current-buffer nntp-server-buffer
     (erase-buffer))
   t)
 
-(defun nnnil-request-post (&optional server)
+(defun nnnil-request-post (&optional _server)
   (setq nnnil-status-string "Read-only server")
   nil)
 
diff --git a/lisp/gnus/nnoo.el b/lisp/gnus/nnoo.el
index 39469d140d9..2260fd694e4 100644
--- a/lisp/gnus/nnoo.el
+++ b/lisp/gnus/nnoo.el
@@ -1,4 +1,4 @@
-;;; nnoo.el --- OO Gnus Backends
+;;; nnoo.el --- OO Gnus Backends  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
@@ -257,7 +257,7 @@
               nnoo-state-alist))
   t)
 
-(defun nnoo-status-message (backend server)
+(defun nnoo-status-message (backend _server)
   (nnheader-get-report backend))
 
 (defun nnoo-server-opened (backend server)
diff --git a/lisp/gnus/nnregistry.el b/lisp/gnus/nnregistry.el
index e78f93d829a..15e41e9d425 100644
--- a/lisp/gnus/nnregistry.el
+++ b/lisp/gnus/nnregistry.el
@@ -1,5 +1,4 @@
-;;; nnregistry.el --- access to articles via Gnus' message-id registry
-;;; -*- coding: utf-8 -*-
+;;; nnregistry.el --- access to articles via Gnus' message-id registry  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2010-2021 Free Software Foundation, Inc.
 
@@ -36,21 +35,21 @@
 
 (nnoo-declare nnregistry)
 
-(deffoo nnregistry-server-opened (server)
+(deffoo nnregistry-server-opened (_server)
   gnus-registry-enabled)
 
-(deffoo nnregistry-close-server (server &optional defs)
+(deffoo nnregistry-close-server (_server &optional _defs)
   t)
 
-(deffoo nnregistry-status-message (server)
+(deffoo nnregistry-status-message (_server)
   nil)
 
-(deffoo nnregistry-open-server (server &optional defs)
+(deffoo nnregistry-open-server (_server &optional _defs)
   gnus-registry-enabled)
 
 (defvar nnregistry-within-nnregistry nil)
 
-(deffoo nnregistry-request-article (id &optional group server buffer)
+(deffoo nnregistry-request-article (id &optional _group _server buffer)
   (and (not nnregistry-within-nnregistry)
        (let* ((nnregistry-within-nnregistry t)
               (group (nth 0 (gnus-registry-get-id-key id 'group)))
diff --git a/lisp/gnus/nnrss.el b/lisp/gnus/nnrss.el
index b62a6412e5d..aa7c8e584a5 100644
--- a/lisp/gnus/nnrss.el
+++ b/lisp/gnus/nnrss.el
@@ -1,4 +1,4 @@
-;;; nnrss.el --- interfacing with RSS
+;;; nnrss.el --- interfacing with RSS  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2001-2021 Free Software Foundation, Inc.
 
@@ -125,7 +125,7 @@ for decoding when the cdr that the data specify is not available.")
       (setq group (decode-coding-string group 'utf-8))
     group))
 
-(deffoo nnrss-retrieve-headers (articles &optional group server fetch-old)
+(deffoo nnrss-retrieve-headers (articles &optional group server _fetch-old)
   (setq group (nnrss-decode-group-name group))
   (nnrss-possibly-change-group group server)
   (let (e)
@@ -173,7 +173,7 @@ for decoding when the cdr that the data specify is not available.")
                     "\n")))))
   'nov)
 
-(deffoo nnrss-request-group (group &optional server dont-check info)
+(deffoo nnrss-request-group (group &optional server dont-check _info)
   (setq group (nnrss-decode-group-name group))
   (nnheader-message 6 "nnrss: Requesting %s..." group)
   (nnrss-possibly-change-group group server)
@@ -188,7 +188,7 @@ for decoding when the cdr that the data specify is not available.")
          t))
     (nnheader-message 6 "nnrss: Requesting %s...done" group)))
 
-(deffoo nnrss-close-group (group &optional server)
+(deffoo nnrss-close-group (_group &optional _server)
   t)
 
 (deffoo nnrss-request-article (article &optional group server buffer)
@@ -200,7 +200,7 @@ for decoding when the cdr that the data specify is not available.")
   (nnrss-possibly-change-group group server)
   (let ((e (assq article nnrss-group-data))
         (nntp-server-buffer (or buffer nntp-server-buffer))
-        post err)
+        err) ;; post
     (when e
       (with-current-buffer nntp-server-buffer
         (erase-buffer)
@@ -222,7 +222,7 @@ for decoding when the cdr that the data specify is not available.")
                    (cons '("Newsgroups" . utf-8)
                          rfc2047-header-encoding-alist)
                  rfc2047-header-encoding-alist))
-              rfc2047-encode-encoded-words body fn)
+              rfc2047-encode-encoded-words body) ;; fn
           (when (or text link enclosure comments)
             (insert "\n")
             (insert "<#multipart type=alternative>\n"
@@ -311,7 +311,7 @@ for decoding when the cdr that the data specify is not available.")
       ;; we return the article number.
       (cons nnrss-group (car e))))))
 
-(deffoo nnrss-open-server (server &optional defs connectionless)
+(deffoo nnrss-open-server (server &optional defs _connectionless)
   (nnrss-read-server-data server)
   (nnoo-change-server 'nnrss server defs)
   t)
@@ -335,7 +335,7 @@ for decoding when the cdr that the data specify is not available.")
         (nnrss-save-group-data group server))
     not-expirable))
 
-(deffoo nnrss-request-delete-group (group &optional force server)
+(deffoo nnrss-request-delete-group (group &optional _force server)
   (setq group (nnrss-decode-group-name group))
   (nnrss-possibly-change-group group server)
   (let (elem)
@@ -561,7 +561,7 @@ which RSS 2.0 allows."
 
 ;;; URL interface
 
-(defun nnrss-no-cache (url)
+(defun nnrss-no-cache (_url)
   "")
 
 (defun nnrss-insert (url)
@@ -613,7 +613,7 @@ which RSS 2.0 allows."
 
 (defun nnrss-check-group (group server)
   (let (file xml subject url extra changed author date feed-subject
-             enclosure comments rss-ns rdf-ns content-ns dc-ns
+             enclosure comments rss-ns  content-ns dc-ns ;; rdf-ns
              hash-index)
     (if (and nnrss-use-local
              (file-exists-p (setq file (expand-file-name
@@ -637,7 +637,7 @@ which RSS 2.0 allows."
         (setq changed t))
       (setq xml (nnrss-fetch url)))
     (setq dc-ns (nnrss-get-namespace-prefix xml "http://purl.org/dc/elements/1.1/")
-          rdf-ns (nnrss-get-namespace-prefix xml "http://www.w3.org/1999/02/22-rdf-syntax-ns#")
+          ;; rdf-ns (nnrss-get-namespace-prefix xml "http://www.w3.org/1999/02/22-rdf-syntax-ns#")
           rss-ns (nnrss-get-namespace-prefix xml "http://purl.org/rss/1.0/")
           content-ns (nnrss-get-namespace-prefix xml "http://purl.org/rss/1.0/modules/content/"))
     (dolist (item (nreverse (nnrss-find-el (intern (concat rss-ns "item")) xml)))
diff --git a/lisp/gnus/nnspool.el b/lisp/gnus/nnspool.el
index cb854178564..ce9ab3c53c1 100644
--- a/lisp/gnus/nnspool.el
+++ b/lisp/gnus/nnspool.el
@@ -1,4 +1,4 @@
-;;; nnspool.el --- spool access for GNU Emacs
+;;; nnspool.el --- spool access for GNU Emacs  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1988-1990, 1993-1998, 2000-2021 Free Software
 ;; Foundation, Inc.
@@ -126,7 +126,7 @@ there.")
 
 (nnoo-define-basics nnspool)
 
-(deffoo nnspool-retrieve-headers (articles &optional group server fetch-old)
+(deffoo nnspool-retrieve-headers (articles &optional group _server fetch-old)
   "Retrieve the headers of ARTICLES."
   (with-current-buffer nntp-server-buffer
     (erase-buffer)
@@ -203,7 +203,7 @@ there.")
                      server nnspool-spool-directory)
     t)))
 
-(deffoo nnspool-request-article (id &optional group server buffer)
+(deffoo nnspool-request-article (id &optional group _server buffer)
   "Select article by message ID (or number)."
   (nnspool-possibly-change-directory group)
   (let ((nntp-server-buffer (or buffer nntp-server-buffer))
@@ -222,7 +222,7 @@ there.")
              (cons nnspool-current-group id)
            ag))))
 
-(deffoo nnspool-request-body (id &optional group server)
+(deffoo nnspool-request-body (id &optional group _server)
   "Select article body by message ID (or number)."
   (nnspool-possibly-change-directory group)
   (let ((res (nnspool-request-article id)))
@@ -233,7 +233,7 @@ there.")
           (delete-region (point-min) (point)))
         res))))
 
-(deffoo nnspool-request-head (id &optional group server)
+(deffoo nnspool-request-head (id &optional group _server)
   "Select article head by message ID (or number)."
   (nnspool-possibly-change-directory group)
   (let ((res (nnspool-request-article id)))
@@ -245,7 +245,7 @@ there.")
         (nnheader-fold-continuation-lines)))
     res))
 
-(deffoo nnspool-request-group (group &optional server dont-check info)
+(deffoo nnspool-request-group (group &optional _server dont-check _info)
   "Select news GROUP."
   (let ((pathname (nnspool-article-pathname group))
         dir)
@@ -269,26 +269,26 @@ there.")
           (nnheader-report 'nnspool "Empty group %s" group)
           (nnheader-insert "211 0 0 0 %s\n" group))))))
 
-(deffoo nnspool-request-type (group &optional article)
+(deffoo nnspool-request-type (_group &optional _article)
   'news)
 
-(deffoo nnspool-close-group (group &optional server)
+(deffoo nnspool-close-group (_group &optional _server)
   t)
 
-(deffoo nnspool-request-list (&optional server)
+(deffoo nnspool-request-list (&optional _server)
   "List active newsgroups."
   (save-excursion
     (or (nnspool-find-file nnspool-active-file)
         (nnheader-report 'nnspool (nnheader-file-error nnspool-active-file)))))
 
-(deffoo nnspool-request-list-newsgroups (&optional server)
+(deffoo nnspool-request-list-newsgroups (&optional _server)
   "List newsgroups (defined in NNTP2)."
   (save-excursion
     (or (nnspool-find-file nnspool-newsgroups-file)
         (nnheader-report 'nnspool (nnheader-file-error
                                    nnspool-newsgroups-file)))))
 
-(deffoo nnspool-request-list-distributions (&optional server)
+(deffoo nnspool-request-list-distributions (&optional _server)
   "List distributions (defined in NNTP2)."
   (save-excursion
     (or (nnspool-find-file nnspool-distributions-file)
@@ -296,7 +296,7 @@ there.")
                                    nnspool-distributions-file)))))
 
 ;; Suggested by Hallvard B Furuseth <h.b.furuseth@usit.uio.no>.
-(deffoo nnspool-request-newgroups (date &optional server)
+(deffoo nnspool-request-newgroups (date &optional _server)
   "List groups created after DATE."
   (if (nnspool-find-file nnspool-active-times-file)
       (save-excursion
@@ -323,7 +323,7 @@ there.")
         t)
     nil))
 
-(deffoo nnspool-request-post (&optional server)
+(deffoo nnspool-request-post (&optional _server)
   "Post a new news in current buffer."
   (save-excursion
     (let* ((process-connection-type nil) ; t bugs out on Solaris
@@ -356,7 +356,7 @@ there.")
 
 ;;; Internal functions.
 
-(defun nnspool-inews-sentinel (proc status)
+(defun nnspool-inews-sentinel (proc _status)
   (with-current-buffer (process-buffer proc)
     (goto-char (point-min))
     (if (or (zerop (buffer-size))
diff --git a/lisp/gnus/nntp.el b/lisp/gnus/nntp.el
index cf89eebbbbb..1eb604d6754 100644
--- a/lisp/gnus/nntp.el
+++ b/lisp/gnus/nntp.el
@@ -1330,7 +1330,7 @@ If SEND-IF-FORCE, only send authinfo to the server if the
     (dolist (entry nntp-server-action-alist)
       (when (string-match (car entry) nntp-server-type)
         (if (not (functionp (cadr entry)))
-            (eval (cadr entry))
+            (eval (cadr entry) t)
           (funcall (cadr entry)))))))
 
 (defun nntp-async-wait (process wait-for buffer decode callback)
diff --git a/lisp/gnus/nnvirtual.el b/lisp/gnus/nnvirtual.el
index 902df868f80..b3b701e4126 100644
--- a/lisp/gnus/nnvirtual.el
+++ b/lisp/gnus/nnvirtual.el
@@ -1,4 +1,4 @@
-;;; nnvirtual.el --- virtual newsgroups access for Gnus
+;;; nnvirtual.el --- virtual newsgroups access for Gnus  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
@@ -94,8 +94,8 @@ It is computed from the marks of individual component groups.")
 (nnoo-define-basics nnvirtual)
 
 
-(deffoo nnvirtual-retrieve-headers (articles &optional newsgroup
-                                             server fetch-old)
+(deffoo nnvirtual-retrieve-headers (articles &optional _newsgroup
+                                             server _fetch-old)
   (when (nnvirtual-possibly-change-server server)
     (with-current-buffer nntp-server-buffer
       (erase-buffer)
@@ -186,7 +186,7 @@ It is computed from the marks of individual component groups.")
 
 (defvoo nnvirtual-last-accessed-component-group nil)
 
-(deffoo nnvirtual-request-article (article &optional group server buffer)
+(deffoo nnvirtual-request-article (article &optional _group server buffer)
   (when (nnvirtual-possibly-change-server server)
     (if (stringp article)
         ;; This is a fetch by Message-ID.
@@ -250,7 +250,7 @@ It is computed from the marks of individual component groups.")
       t)))
 
 
-(deffoo nnvirtual-request-group (group &optional server dont-check info)
+(deffoo nnvirtual-request-group (group &optional server dont-check _info)
   (nnvirtual-possibly-change-server server)
   (setq nnvirtual-component-groups
         (delete (nnvirtual-current-group) nnvirtual-component-groups))
@@ -269,7 +269,7 @@ It is computed from the marks of individual component groups.")
                      nnvirtual-mapping-len nnvirtual-mapping-len group))))
 
 
-(deffoo nnvirtual-request-type (group &optional article)
+(deffoo nnvirtual-request-type (_group &optional article)
   (if (not article)
       'unknown
     (if (numberp article)
@@ -279,7 +279,7 @@ It is computed from the marks of individual component groups.")
       (gnus-request-type
        nnvirtual-last-accessed-component-group nil))))
 
-(deffoo nnvirtual-request-update-mark (group article mark)
+(deffoo nnvirtual-request-update-mark (_group article mark)
   (let* ((nart (nnvirtual-map-article article))
          (cgroup (car nart)))
     (when (and nart
@@ -291,22 +291,22 @@ It is computed from the marks of individual component groups.")
   mark)
 
 
-(deffoo nnvirtual-close-group (group &optional server)
+(deffoo nnvirtual-close-group (_group &optional server)
   (when (and (nnvirtual-possibly-change-server server)
              (not (gnus-ephemeral-group-p (nnvirtual-current-group))))
     (nnvirtual-update-read-and-marked t t))
   t)
 
 
-(deffoo nnvirtual-request-newgroups (date &optional server)
+(deffoo nnvirtual-request-newgroups (_date &optional _server)
   (nnheader-report 'nnvirtual "NEWGROUPS is not supported."))
 
 
-(deffoo nnvirtual-request-list-newsgroups (&optional server)
+(deffoo nnvirtual-request-list-newsgroups (&optional _server)
   (nnheader-report 'nnvirtual "LIST NEWSGROUPS is not implemented."))
 
 
-(deffoo nnvirtual-request-update-info (group info &optional server)
+(deffoo nnvirtual-request-update-info (_group info &optional server)
   (when (and (nnvirtual-possibly-change-server server)
              (not nnvirtual-info-installed))
     ;; Install the precomputed lists atomically, so the virtual group
@@ -321,7 +321,7 @@ It is computed from the marks of individual component groups.")
     t))
 
 
-(deffoo nnvirtual-catchup-group (group &optional server all)
+(deffoo nnvirtual-catchup-group (_group &optional server all)
   (when (and (nnvirtual-possibly-change-server server)
              (not (gnus-ephemeral-group-p (nnvirtual-current-group))))
     ;; copy over existing marks first, in case they set anything
@@ -339,12 +339,12 @@ It is computed from the marks of individual component groups.")
         (gnus-group-catchup-current nil all)))))
 
 
-(deffoo nnvirtual-find-group-art (group article)
+(deffoo nnvirtual-find-group-art (_group article)
   "Return the real group and article for virtual GROUP and ARTICLE."
   (nnvirtual-map-article article))
 
 
-(deffoo nnvirtual-request-post (&optional server)
+(deffoo nnvirtual-request-post (&optional _server)
   (if (not gnus-message-group-art)
       (nnheader-report 'nnvirtual "Can't post to an nnvirtual group")
     (let ((group (car (nnvirtual-find-group-art
@@ -353,8 +353,8 @@ It is computed from the marks of individual component groups.")
       (gnus-request-post (gnus-find-method-for-group group)))))
 
 
-(deffoo nnvirtual-request-expire-articles (articles group
-                                                    &optional server force)
+(deffoo nnvirtual-request-expire-articles ( _articles _group
+                                            &optional server _force)
   (nnvirtual-possibly-change-server server)
   (setq nnvirtual-component-groups
         (delete (nnvirtual-current-group) nnvirtual-component-groups))
diff --git a/lisp/gnus/nnweb.el b/lisp/gnus/nnweb.el
index dd71bea72e2..f08dc47e313 100644
--- a/lisp/gnus/nnweb.el
+++ b/lisp/gnus/nnweb.el
@@ -1,4 +1,4 @@
-;;; nnweb.el --- retrieving articles via web search engines
+;;; nnweb.el --- retrieving articles via web search engines  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996-2021 Free Software Foundation, Inc.
 
@@ -96,7 +96,7 @@ Valid types include `google', `dejanews', and `gmane'.")
 
 (nnoo-define-basics nnweb)
 
-(deffoo nnweb-retrieve-headers (articles &optional group server fetch-old)
+(deffoo nnweb-retrieve-headers (articles &optional group server _fetch-old)
   (nnweb-possibly-change-server group server)
   (with-current-buffer nntp-server-buffer
     (erase-buffer)
@@ -117,7 +117,7 @@ Valid types include `google', `dejanews', and `gmane'.")
     (nnweb-write-active)
     (nnweb-write-overview group)))
 
-(deffoo nnweb-request-group (group &optional server dont-check info)
+(deffoo nnweb-request-group (group &optional server dont-check _info)
   (nnweb-possibly-change-server group server)
   (unless (or nnweb-ephemeral-p
               dont-check
@@ -156,7 +156,7 @@ Valid types include `google', `dejanews', and `gmane'.")
                      (let ((fetch (nnweb-definition 'id))
                            (art (when (string-match "^<\\(.*\\)>$" article)
                                   (match-string 1 article)))
-                           active)
+                           ) ;; active
                        (when (and fetch art)
                          (setq url (format fetch
                                            (mm-url-form-encode-xwfu art)))
@@ -184,19 +184,19 @@ Valid types include `google', `dejanews', and `gmane'.")
     (nnmail-generate-active (list (assoc server nnweb-group-alist)))
     t))
 
-(deffoo nnweb-request-update-info (group info &optional server))
+(deffoo nnweb-request-update-info (_group _info &optional _server))
 
 (deffoo nnweb-asynchronous-p ()
   nil)
 
-(deffoo nnweb-request-create-group (group &optional server args)
+(deffoo nnweb-request-create-group (group &optional server _args)
   (nnweb-possibly-change-server nil server)
   (nnweb-request-delete-group group)
   (push `(,group ,(cons 1 0)) nnweb-group-alist)
   (nnweb-write-active)
   t)
 
-(deffoo nnweb-request-delete-group (group &optional force server)
+(deffoo nnweb-request-delete-group (group &optional _force server)
   (nnweb-possibly-change-server group server)
   (gnus-alist-pull group nnweb-group-alist t)
   (nnweb-write-active)
@@ -317,7 +317,7 @@ Valid types include `google', `dejanews', and `gmane'.")
   (let ((i 0)
         (case-fold-search t)
         (active (cadr (assoc nnweb-group nnweb-group-alist)))
-        Subject Score Date Newsgroups From
+        Subject Date Newsgroups From
         map url mid)
     (unless active
       (push (list nnweb-group (setq active (cons 1 0)))
diff --git a/lisp/gnus/score-mode.el b/lisp/gnus/score-mode.el
index b8726c03c3e..d3ed3600ad9 100644
--- a/lisp/gnus/score-mode.el
+++ b/lisp/gnus/score-mode.el
@@ -1,4 +1,4 @@
-;;; score-mode.el --- mode for editing Gnus score files
+;;; score-mode.el --- mode for editing Gnus score files  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 1996, 2001-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/smiley.el b/lisp/gnus/smiley.el
index 9884bcc0752..3ee59479cf5 100644
--- a/lisp/gnus/smiley.el
+++ b/lisp/gnus/smiley.el
@@ -1,4 +1,4 @@
-;;; smiley.el --- displaying smiley faces
+;;; smiley.el --- displaying smiley faces  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2000-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/spam-report.el b/lisp/gnus/spam-report.el
index 11d653d5374..d87a6c2af0d 100644
--- a/lisp/gnus/spam-report.el
+++ b/lisp/gnus/spam-report.el
@@ -1,4 +1,4 @@
-;;; spam-report.el --- Reporting spam
+;;; spam-report.el --- Reporting spam  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2002-2021 Free Software Foundation, Inc.
 
diff --git a/lisp/gnus/spam-stat.el b/lisp/gnus/spam-stat.el
index 1980bd1d747..70753cad9ca 100644
--- a/lisp/gnus/spam-stat.el
+++ b/lisp/gnus/spam-stat.el
@@ -1,4 +1,4 @@
-;;; spam-stat.el --- detecting spam based on statistics
+;;; spam-stat.el --- detecting spam based on statistics  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2002-2021 Free Software Foundation, Inc.
 
@@ -251,9 +251,6 @@ Use `spam-stat-ngood', `spam-stat-nbad', `spam-stat-good',
 (defvar spam-stat-nbad 0
   "The number of bad mails in the dictionary.")
 
-(defvar spam-stat-error-holder nil
-  "A holder for condition-case errors while scoring buffers.")
-
 (defsubst spam-stat-good (entry)
   "Return the number of times this word belongs to good mails."
   (aref entry 0))
@@ -477,8 +474,8 @@ The default score for unknown words is stored in
 These are the words whose spam-stat differs the most from 0.5.
 The list returned contains elements of the form \(WORD SCORE DIFF),
 where DIFF is the difference between SCORE and 0.5."
-  (let (result word score)
-    (maphash (lambda (word ignore)
+  (let (result score) ;; word
+    (maphash (lambda (word _ignore)
                (setq score (spam-stat-score-word word)
                      result (cons (list word score (abs (- score 0.5)))
                                   result)))
@@ -498,8 +495,7 @@ Add user supplied modifications if supplied."
           (/ prod (+ prod (apply #'* (mapcar #'(lambda (x) (- 1 x))
                                              probs)))))
          (score1s
-          (condition-case
-              spam-stat-error-holder
+          (condition-case nil
               (spam-stat-score-buffer-user score0)
             (error nil)))
          (ans
@@ -522,7 +518,7 @@ Add user supplied modifications if supplied."
 Use this function on `nnmail-split-fancy'.  If you are interested in
 the raw data used for the last run of `spam-stat-score-buffer',
 check the variable `spam-stat-score-data'."
-  (condition-case spam-stat-error-holder
+  (condition-case err
       (progn
         (set-buffer spam-stat-buffer)
         (goto-char (point-min))
@@ -532,7 +528,7 @@ check the variable `spam-stat-score-data'."
                     (push entry nnmail-split-trace))
                   spam-stat-score-data))
           spam-stat-split-fancy-spam-group))
-    (error (message "Error in spam-stat-split-fancy: %S" spam-stat-error-holder)
+    (error (message "Error in spam-stat-split-fancy: %S" err)
            nil)))
 
 ;; Testing
diff --git a/lisp/gnus/spam-wash.el b/lisp/gnus/spam-wash.el
index 1c755fb464e..bb2a1b97ada 100644
--- a/lisp/gnus/spam-wash.el
+++ b/lisp/gnus/spam-wash.el
@@ -1,4 +1,4 @@
-;;; spam-wash.el --- wash spam before analysis
+;;; spam-wash.el --- wash spam before analysis  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2004, 2007-2021 Free Software Foundation, Inc.
 
@@ -43,7 +43,7 @@
              (handles (or (mm-dissect-buffer nil gnus-article-loose-mime)
                           (and gnus-article-emulate-mime
                                (mm-uu-dissect))))
-             handle)
+             ) ;; handle
           (when gnus-article-mime-handles
             (mm-destroy-parts gnus-article-mime-handles)
             (setq gnus-article-mime-handle-alist nil))
diff --git a/lisp/gnus/spam.el b/lisp/gnus/spam.el
index 00dcd00ceab..f7288c98f6f 100644
--- a/lisp/gnus/spam.el
+++ b/lisp/gnus/spam.el
@@ -1,4 +1,4 @@
-;;; spam.el --- Identifying spam
+;;; spam.el --- Identifying spam  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2002-2021 Free Software Foundation, Inc.
 
@@ -1387,7 +1387,7 @@ In the case of mover backends, checks the setting of
          (gnus-check-backend-function
           'request-move-article gnus-newsgroup-name))
         (respool-method (gnus-find-method-for-group gnus-newsgroup-name))
-        article mark deletep respool valid-move-destinations)
+        deletep respool valid-move-destinations) ;; article mark
 
     (when (member 'respool groups)
       (setq respool t)                  ; boolean for later
@@ -1807,7 +1807,7 @@ See the Info node `(gnus)Fancy Mail Splitting' for more details."
            (log-function (if unregister
                              'spam-log-undo-registration
                            'spam-log-processing-to-registry))
-           article articles)
+           articles) ;; article
 
       (when run-function
         ;; make list of articles, using specific-articles if given
@@ -1910,7 +1910,7 @@ See the Info node `(gnus)Fancy Mail Splitting' for more details."
 
 ;; undo a ham- or spam-processor registration (the group is not used)
 (defun spam-log-undo-registration (id type classification backend
-                                      &optional group)
+                                      &optional _group)
   (when (and spam-log-to-registry
              (spam-log-unregistration-needed-p id type classification backend))
     (if (and (stringp id)
@@ -1918,7 +1918,7 @@ See the Info node `(gnus)Fancy Mail Splitting' for more details."
              (spam-classification-valid-p classification)
              (spam-backend-valid-p backend))
         (let ((cell-list (gnus-registry-get-id-key id type))
-              new-cell-list found)
+              new-cell-list) ;; found
           (dolist (cell cell-list)
             (unless (and (eq classification (nth 0 cell))
                          (eq backend (nth 1 cell)))
@@ -2050,7 +2050,7 @@ See the Info node `(gnus)Fancy Mail Splitting' for more details."
 (declare-function bbdb-create-internal "bbdb-com" (&rest spec))
 
 ;; when the BBDB changes, we want to clear out our cache
-(defun spam-clear-cache-BBDB (&rest immaterial)
+(defun spam-clear-cache-BBDB (&rest _immaterial)
   (spam-clear-cache 'spam-use-BBDB))
 
 (when (featurep 'bbdb-com)
@@ -2150,7 +2150,7 @@ Uses `gnus-newsgroup-name' if category is nil (for ham registration)."
   (let ((category (or category gnus-newsgroup-name))
         (add-or-delete-option (if unregister "-d" "-i"))
         (db (spam-get-ifile-database-parameter))
-        parameters)
+        ) ;; parameters
     (with-temp-buffer
       (dolist (article articles)
         (let ((article-string (spam-get-article-as-string article)))
@@ -2184,7 +2184,7 @@ Uses `gnus-newsgroup-name' if category is nil (for ham registration)."
   "Check the spam-stat backend for the classification of this message."
   (let ((spam-stat-split-fancy-spam-group spam-split-group) ; override
         (spam-stat-buffer (buffer-name)) ; stat the current buffer
-        category return)
+        ) ;; category return
     (spam-stat-split-fancy)))
 
 (defun spam-stat-register-spam-routine (articles &optional unregister)
@@ -2335,7 +2335,7 @@ With a non-nil REMOVE, remove the ADDRESSES."
 
 (defun spam-from-listed-p (type)
   (let ((from (message-fetch-field "from"))
-        found)
+        ) ;; found
     (spam-filelist-check-cache type from)))
 
 (defun spam-filelist-register-routine (articles blacklist &optional unregister)
@@ -2345,7 +2345,7 @@ With a non-nil REMOVE, remove the ADDRESSES."
          (if blacklist 'spam-enter-blacklist 'spam-enter-whitelist))
         (remove-function
          (if blacklist 'spam-enter-whitelist 'spam-enter-blacklist))
-        from addresses unregister-list article-unregister-list)
+        addresses unregister-list article-unregister-list) ;; from
     (dolist (article articles)
       (let ((from (spam-fetch-field-from-fast article))
             (id (spam-fetch-field-message-id-fast article))
@@ -2562,13 +2562,13 @@ With a non-nil REMOVE, remove the ADDRESSES."
 (defun spam-spamoracle-learn-ham (articles &optional unregister)
   (spam-spamoracle-learn articles nil unregister))
 
-(defun spam-spamoracle-unlearn-ham (articles &optional unregister)
+(defun spam-spamoracle-unlearn-ham (articles &optional _unregister)
   (spam-spamoracle-learn-ham articles t))
 
 (defun spam-spamoracle-learn-spam (articles &optional unregister)
   (spam-spamoracle-learn articles t unregister))
 
-(defun spam-spamoracle-unlearn-spam (articles &optional unregister)
+(defun spam-spamoracle-unlearn-spam (articles &optional _unregister)
   (spam-spamoracle-learn-spam articles t))
 
 ;;}}}