; Simplify (with-current-buffer (get-buffer ...) ...)

There's no need to call 'get-buffer', since 'with-current-buffer'
does that internally.
* lisp/calendar/todo-mode.el (todo-merge-category):
* lisp/comint.el (comint-dynamic-list-completions):
* lisp/emacs-lisp/checkdoc.el (checkdoc-error):
* lisp/emacs-lisp/debug.el (debug, debugger-record-expression):
* lisp/emacs-lisp/eieio-opt.el (eieio-browse):
* lisp/emacs-lisp/re-builder.el (reb-restart-font-lock):
* lisp/erc/erc-dcc.el (erc-dcc-do-LIST-command):
* lisp/eshell/em-unix.el (eshell-poor-mans-grep):
* lisp/gnus/gnus-group.el (gnus-add-mark):
* lisp/net/eww.el (eww-next-bookmark, eww-previous-bookmark):
* lisp/net/sieve.el (sieve-upload):
* lisp/net/tramp-cmds.el (tramp-cleanup-some-buffers):
* lisp/obsolete/quickurl.el (quickurl-list-populate-buffer):
* lisp/org/ob-calc.el: (org-babel-execute:calc):
* lisp/org/org-agenda.el (org-agenda-use-sticky-p):
* lisp/pcomplete.el (pcomplete-show-completions):
* lisp/progmodes/bug-reference.el
(bug-reference--try-setup-gnus-article):
* lisp/progmodes/idlw-help.el
(idlwave-highlight-linked-completions):
* lisp/progmodes/verilog-mode.el (verilog-preprocess):
* lisp/replace.el (occur-1):
* lisp/term.el (term-dynamic-list-completions):
* lisp/time.el (world-clock-update):
* lisp/url/url-cache.el (url-store-in-cache):
* lisp/vc/vc-cvs.el (vc-cvs-merge, vc-cvs-merge-news):
* lisp/vc/vc-rcs.el (vc-rcs-system-release):
* lisp/vc/vc-svn.el (vc-svn-merge, vc-svn-merge-news):
* test/lisp/calendar/icalendar-tests.el
(icalendar-tests--get-error-string-for-export):
* test/lisp/erc/erc-dcc-tests.el
(pcomplete/erc-mode/DCC--get-1flag)
(pcomplete/erc-mode/DCC--get-2flags)
(pcomplete/erc-mode/DCC--get-2flags-reverse):
* test/lisp/erc/erc-networks-tests.el
(erc-networks--rename-server-buffer--existing--noreuse):
* test/lisp/erc/erc-scenarios-services-misc.el
(erc-scenarios-services-misc--reconnect-retry-nick):
* test/lisp/erc/erc-tests.el (erc--refresh-prompt):
Replace (with-current-buffer (get-buffer ...) ...) with
(with-current-buffer ...).

lisp/emacs-lisp/checkdoc.el

@@ -2794,7 +2794,7 @@ function called to create the messages."
                     ": " msg)))
     (if (string= checkdoc-diagnostic-buffer "*warn*")
         (warn (apply #'concat text))
-      (with-current-buffer (get-buffer checkdoc-diagnostic-buffer)
+      (with-current-buffer checkdoc-diagnostic-buffer
           (let ((inhibit-read-only t)
                 (pt (point-max)))
             (goto-char pt)

lisp/emacs-lisp/debug.el

@@ -200,7 +200,7 @@ the debugger will not be entered."
       (let (debugger-value
 	    (debugger-previous-state
              (if (get-buffer "*Backtrace*")
-                 (with-current-buffer (get-buffer "*Backtrace*")
+                 (with-current-buffer "*Backtrace*"
                    (debugger--save-buffer-state))))
             (debugger-args args)
 	    (debugger-buffer (get-buffer-create "*Backtrace*"))
@@ -651,7 +651,7 @@ Complete list of commands:
     (princ (debugger-eval-expression exp))
     (terpri))
 
-  (with-current-buffer (get-buffer debugger-record-buffer)
+  (with-current-buffer debugger-record-buffer
     (message "%s"
 	     (buffer-substring (line-beginning-position 0)
 			       (line-end-position 0)))))

lisp/emacs-lisp/eieio-opt.el

@@ -50,7 +50,7 @@ variable `eieio-default-superclass'."
   (if (not root-class) (setq root-class 'eieio-default-superclass))
   (cl-check-type root-class class)
   (display-buffer (get-buffer-create "*EIEIO OBJECT BROWSE*") t)
-  (with-current-buffer (get-buffer "*EIEIO OBJECT BROWSE*")
+  (with-current-buffer "*EIEIO OBJECT BROWSE*"
     (erase-buffer)
     (goto-char 0)
     (eieio-browse-tree root-class "" "")

lisp/emacs-lisp/re-builder.el

@@ -825,7 +825,7 @@ If SUBEXP is non-nil mark only the corresponding sub-expressions."
 
 (defun reb-restart-font-lock ()
   "Restart `font-lock-mode' to fit current regexp format."
-  (with-current-buffer (get-buffer reb-buffer)
+  (with-current-buffer reb-buffer
     (let ((font-lock-is-on font-lock-mode))
       (font-lock-mode -1)
       (kill-local-variable 'font-lock-set-defaults)