Move side-effect-free and pure declarations to function definitions

Some Lisp functions still had their `side-effect-free` and `pure`
properties declared in byte-opt.el; do it at their definition instead.
The lists in byte-opt.el now only contain functions implemented in C
and function aliases.

* lisp/emacs-lisp/byte-opt.el (side-effect-free-fns)
(side-effect-and-error-free-fns, pure-fns):
Remove functions whose properties are now declared elsewhere
and some obsolete entries.
* lisp/custom.el (custom-variable-p):
* lisp/emacs-lisp/lisp.el (buffer-end):
* lisp/emacs-lisp/regexp-opt.el (regexp-opt):
* lisp/env.el (getenv):
* lisp/simple.el (count-lines, mark, string-empty-p, lax-plist-get):
* lisp/subr.el (ignore, always, zerop, fixnump, bignump, lsh, last)
(eventp, mouse-movement-p, log10, memory-limit, string-greaterp)
(interactive-p):
* lisp/window.el (get-lru-window, get-largest-window, (window-edges)
(window-body-edges, window-pixel-edges, window-body-pixel-edges)
(window-absolute-pixel-edges, window-absolute-body-pixel-edges)
(one-window-p):
Declare functions `side-effect-free` and/or `pure` as appropriate.

lisp/custom.el

@@ -665,6 +665,7 @@ If NOSET is non-nil, don't bother autoloading LOAD when setting the variable."
 A customizable variable is either (i) a variable whose property
 list contains a non-nil `standard-value' or `custom-autoload'
 property, or (ii) an alias for another customizable variable."
+  (declare (side-effect-free t))
   (when (symbolp variable)
     (setq variable (indirect-variable variable))
     (or (get variable 'standard-value)

lisp/emacs-lisp/byte-opt.el

@@ -1647,7 +1647,7 @@ See Info node `(elisp) Integer Basics'."
 	 capitalize car-less-than-car car cdr ceiling char-after char-before
 	 char-equal char-to-string char-width compare-strings
 	 window-configuration-equal-p concat coordinates-in-window-p
-	 copy-alist copy-sequence copy-marker copysign cos count-lines
+	 copy-alist copy-sequence copy-marker copysign cos
 	 current-time-string current-time-zone
 	 decode-char
 	 decode-time default-boundp default-value documentation downcase
@@ -1659,26 +1659,24 @@ See Info node `(elisp) Integer Basics'."
 	 float float-time floor format format-time-string frame-first-window
 	 frame-root-window frame-selected-window
 	 frame-visible-p fround ftruncate
-	 get gethash get-buffer get-buffer-window getenv get-file-buffer
+	 get gethash get-buffer get-buffer-window get-file-buffer
 	 hash-table-count
 	 int-to-string intern-soft isnan
 	 keymap-parent
-         lax-plist-get ldexp
+         ldexp
          length length< length> length=
          line-beginning-position line-end-position pos-bol pos-eol
 	 local-variable-if-set-p local-variable-p locale-info
-	 log log10 logand logb logcount logior lognot logxor lsh
+	 log logand logb logcount logior lognot logxor
-	 make-byte-code make-list make-string make-symbol mark marker-buffer max
+	 make-byte-code make-list make-string make-symbol marker-buffer max
          match-beginning match-end
 	 member memq memql min minibuffer-selected-window minibuffer-window
 	 mod multibyte-char-to-unibyte next-window nth nthcdr number-to-string
-	 parse-colon-path
 	 prefix-numeric-value previous-window prin1-to-string propertize
-	 degrees-to-radians
+	 rassq rassoc read-from-string
-	 radians-to-degrees rassq rassoc read-from-string regexp-opt
          regexp-quote region-beginning region-end reverse round
 	 sin sqrt string string< string= string-equal string-lessp
-         string> string-greaterp string-empty-p string-blank-p
+         string>
          string-search string-to-char
 	 string-to-number string-to-syntax substring
 	 sxhash sxhash-equal sxhash-eq sxhash-eql
@@ -1687,45 +1685,40 @@ See Info node `(elisp) Integer Basics'."
 	 string-to-multibyte
 	 take tan time-convert truncate
 	 unibyte-char-to-multibyte upcase user-full-name
-	 user-login-name user-original-login-name custom-variable-p
+	 user-login-name user-original-login-name
 	 vconcat
-	 window-absolute-pixel-edges window-at window-body-height
+	 window-at window-body-height
 	 window-body-width window-buffer window-dedicated-p window-display-table
-	 window-combination-limit window-edges window-frame window-fringes
+	 window-combination-limit window-frame window-fringes
 	 window-height window-hscroll window-inside-edges
 	 window-inside-absolute-pixel-edges window-inside-pixel-edges
 	 window-left-child window-left-column window-margins window-minibuffer-p
 	 window-next-buffers window-next-sibling window-new-normal
 	 window-new-total window-normal-size window-parameter window-parameters
-	 window-parent window-pixel-edges window-point window-prev-buffers
+	 window-parent window-point window-prev-buffers
          window-prev-sibling window-scroll-bars
 	 window-start window-text-height window-top-child window-top-line
 	 window-total-height window-total-width window-use-time window-vscroll
-	 window-width zerop))
+	 window-width))
       (side-effect-and-error-free-fns
-       '(always arrayp atom
+       '(arrayp atom
-	 bignump bobp bolp bool-vector-p
+	 bobp bolp bool-vector-p
-	 buffer-end buffer-list buffer-size buffer-string bufferp
+	 buffer-list buffer-size buffer-string bufferp
 	 car-safe case-table-p cdr-safe char-or-string-p characterp
 	 charsetp commandp cons consp
 	 current-buffer current-global-map current-indentation
 	 current-local-map current-minor-mode-maps current-time
-	 eobp eolp eq equal eventp
+	 eobp eolp eq equal
-	 fixnump floatp following-char framep
+	 floatp following-char framep
-	 get-largest-window get-lru-window
 	 hash-table-p
-         ;; `ignore' isn't here because we don't want calls to it elided;
+	 identity integerp integer-or-marker-p
-         ;; see `byte-compile-ignore'.
-	 identity integerp integer-or-marker-p interactive-p
 	 invocation-directory invocation-name
 	 keymapp keywordp
 	 list listp
 	 make-marker mark-marker markerp max-char
-	 memory-limit
-	 mouse-movement-p
 	 natnump nlistp not null number-or-marker-p numberp
-	 one-window-p overlayp
+	 overlayp
-	 point point-marker point-min point-max preceding-char primary-charset
+	 point point-marker point-min point-max preceding-char
 	 processp proper-list-p
 	 recent-keys recursion-depth
 	 safe-length selected-frame selected-window sequencep
@@ -1761,7 +1754,7 @@ See Info node `(elisp) Integer Basics'."
 ;; values if a marker is moved.
 
 (let ((pure-fns
-       '(concat regexp-opt regexp-quote
+       '(concat regexp-quote
 	 string-to-char string-to-syntax symbol-name
          eq eql
          = /= < <= >= > min max
@@ -1770,8 +1763,7 @@ See Info node `(elisp) Integer Basics'."
          copysign isnan ldexp float logb
          floor ceiling round truncate
          ffloor fceiling fround ftruncate
-         string= string-equal string< string-lessp string> string-greaterp
+         string= string-equal string< string-lessp string>
-         string-empty-p string-blank-p
          string-search
          consp atom listp nlistp proper-list-p
          sequencep arrayp vectorp stringp bool-vector-p hash-table-p
@@ -1780,20 +1772,19 @@ See Info node `(elisp) Integer Basics'."
          integer-or-marker-p number-or-marker-p char-or-string-p
          symbolp keywordp
          type-of
-         identity ignore
+         identity
 
          ;; The following functions are pure up to mutation of their
          ;; arguments.  This is pure enough for the purposes of
          ;; constant folding, but not necessarily for all kinds of
          ;; code motion.
-         car cdr car-safe cdr-safe nth nthcdr last take
+         car cdr car-safe cdr-safe nth nthcdr take
          equal
          length safe-length
          memq memql member
          ;; `assoc' and `assoc-default' are excluded since they are
          ;; impure if the test function is (consider `string-match').
          assq rassq rassoc
-         lax-plist-get
          aref elt
          base64-decode-string base64-encode-string base64url-encode-string
          bool-vector-subsetp

lisp/emacs-lisp/lisp.el

@@ -519,6 +519,7 @@ major mode's decisions about context.")
   "Return the \"far end\" position of the buffer, in direction ARG.
 If ARG is positive, that's the end of the buffer.
 Otherwise, that's the beginning of the buffer."
+  (declare (side-effect-free error-free))
   (if (> arg 0) (point-max) (point-min)))
 
 (defun end-of-defun (&optional arg interactive)

lisp/emacs-lisp/regexp-opt.el

@@ -130,6 +130,7 @@ usually more efficient than that of a simplified version:
      (concat (car parens)
              (mapconcat \\='regexp-quote strings \"\\\\|\")
              (cdr parens))))"
+  (declare (pure t) (side-effect-free t))
   (save-match-data
     ;; Recurse on the sorted list.
     (let* ((max-lisp-eval-depth 10000)

lisp/env.el

@@ -205,6 +205,7 @@ Otherwise, this function searches `process-environment' for
 VARIABLE.  If it is not found there, then it continues the search
 in the environment list of the selected frame."
   (interactive (list (read-envvar-name "Get environment variable: " t)))
+  (declare (side-effect-free t))
   (let ((value (getenv-internal (if (multibyte-string-p variable)
 				    (encode-coding-string
 				     variable locale-coding-system)

lisp/simple.el

@@ -1755,6 +1755,7 @@ not at the start of a line.
 
 When IGNORE-INVISIBLE-LINES is non-nil, invisible lines are not
 included in the count."
+  (declare (side-effect-free t))
   (save-excursion
     (save-restriction
       (narrow-to-region start end)
@@ -6830,6 +6831,7 @@ is active, and returns an integer or nil in the usual way.
 
 If you are using this in an editing command, you are most likely making
 a mistake; see the documentation of `set-mark'."
+  (declare (side-effect-free t))
   (if (or force (not transient-mark-mode) mark-active mark-even-if-inactive)
       (marker-position (mark-marker))
     (signal 'mark-inactive nil)))
@@ -10840,6 +10842,7 @@ If the buffer doesn't exist, create it first."
 
 (defsubst string-empty-p (string)
   "Check whether STRING is empty."
+  (declare (pure t) (side-effect-free t))
   (string= string ""))
 
 (defun read-signal-name ()
@@ -10857,7 +10860,7 @@ If the buffer doesn't exist, create it first."
 
 (defun lax-plist-get (plist prop)
   "Extract a value from a property list, comparing with `equal'."
-  (declare (obsolete plist-get "29.1"))
+  (declare (pure t) (side-effect-free t) (obsolete plist-get "29.1"))
   (plist-get plist prop #'equal))
 
 (defun lax-plist-put (plist prop val)

lisp/subr.el

@@ -422,7 +422,9 @@ PREFIX is a string, and defaults to \"g\"."
   "Do nothing and return nil.
 This function accepts any number of ARGUMENTS, but ignores them.
 Also see `always'."
-  (declare (completion ignore))
+  ;; Not declared `side-effect-free' because we don't want calls to it
+  ;; elided; see `byte-compile-ignore'.
+  (declare (pure t) (completion ignore))
   (interactive)
   nil)
 
@@ -430,6 +432,7 @@ Also see `always'."
   "Do nothing and return t.
 This function accepts any number of ARGUMENTS, but ignores them.
 Also see `ignore'."
+  (declare (pure t) (side-effect-free error-free))
   t)
 
 ;; Signal a compile-error if the first arg is missing.
@@ -509,16 +512,19 @@ was called."
   "Return t if NUMBER is zero."
   ;; Used to be in C, but it's pointless since (= 0 n) is faster anyway because
   ;; = has a byte-code.
-  (declare (compiler-macro (lambda (_) `(= 0 ,number))))
+  (declare (pure t) (side-effect-free t)
+           (compiler-macro (lambda (_) `(= 0 ,number))))
   (= 0 number))
 
 (defun fixnump (object)
   "Return t if OBJECT is a fixnum."
+  (declare (side-effect-free error-free))
   (and (integerp object)
        (<= most-negative-fixnum object most-positive-fixnum)))
 
 (defun bignump (object)
   "Return t if OBJECT is a bignum."
+  (declare (side-effect-free error-free))
   (and (integerp object) (not (fixnump object))))
 
 (defun lsh (value count)
@@ -533,7 +539,8 @@ instead."
             (lambda (form)
               (macroexp-warn-and-return
                (format-message "avoid `lsh'; use `ash' instead")
-               form '(suspicious lsh) t form))))
+               form '(suspicious lsh) t form)))
+           (side-effect-free t))
   (when (and (< value 0) (< count 0))
     (when (< value most-negative-fixnum)
       (signal 'args-out-of-range (list value count)))
@@ -706,7 +713,7 @@ instead."
 If LIST is nil, return nil.
 If N is non-nil, return the Nth-to-last link of LIST.
 If N is bigger than the length of LIST, return LIST."
-  (declare (side-effect-free t))
+  (declare (pure t) (side-effect-free t))    ; pure up to mutation
   (if n
       (and (>= n 0)
            (let ((m (safe-length list)))
@@ -1525,6 +1532,7 @@ See also `current-global-map'.")
 
 (defun eventp (object)
   "Return non-nil if OBJECT is an input event or event object."
+  (declare (pure t) (side-effect-free error-free))
   (or (integerp object)
       (and (if (consp object)
                (setq object (car object))
@@ -1587,6 +1595,7 @@ in the current Emacs session, then this function may return nil."
 
 (defsubst mouse-movement-p (object)
   "Return non-nil if OBJECT is a mouse movement event."
+  (declare (side-effect-free error-free))
   (eq (car-safe object) 'mouse-movement))
 
 (defun mouse-event-p (object)
@@ -1859,7 +1868,7 @@ be a list of the form returned by `event-start' and `event-end'."
 
 (defun log10 (x)
   "Return (log X 10), the log base 10 of X."
-  (declare (obsolete log "24.4"))
+  (declare (side-effect-free t) (obsolete log "24.4"))
   (log x 10))
 
 (set-advertised-calling-convention
@@ -2983,6 +2992,7 @@ It can be retrieved with `(process-get PROCESS PROPNAME)'."
 
 (defun memory-limit ()
   "Return an estimate of Emacs virtual memory usage, divided by 1024."
+  (declare (side-effect-free error-free))
   (let ((default-directory temporary-file-directory))
     (or (cdr (assq 'vsize (process-attributes (emacs-pid)))) 0)))
 
@@ -5544,6 +5554,7 @@ consisting of STR followed by an invisible left-to-right mark
   "Return non-nil if STRING1 is greater than STRING2 in lexicographic order.
 Case is significant.
 Symbols are also allowed; their print names are used instead."
+  (declare (pure t) (side-effect-free t))
   (string-lessp string2 string1))
 
 
@@ -6187,7 +6198,8 @@ To test whether a function can be called interactively, use
 `commandp'."
   ;; Kept around for now.  See discussion at:
   ;; https://lists.gnu.org/r/emacs-devel/2020-08/msg00564.html
-  (declare (obsolete called-interactively-p "23.2"))
+  (declare (obsolete called-interactively-p "23.2")
+           (side-effect-free error-free))
   (called-interactively-p 'interactive))
 
 (defun internal-push-keymap (keymap symbol)

lisp/window.el

@@ -2522,6 +2522,7 @@ selected frame and no others.
 `display-buffer-avoid-small-windows', if non-nil, is also taken into
 consideration.  Windows whose height is smaller that the value of that
 variable will be avoided if larger windows are available."
+  (declare (side-effect-free error-free))
   (let ((windows (window-list-1 nil 'nomini all-frames))
         best-window best-time second-best-window second-best-time time)
     (dolist (window windows)
@@ -2603,6 +2604,7 @@ have special meanings:
 
 Any other value of ALL-FRAMES means consider all windows on the
 selected frame and no others."
+  (declare (side-effect-free error-free))
   (let ((best-size 0)
 	best-window size)
     (dolist (window (window-list-1 nil 'nomini all-frames))
@@ -3801,6 +3803,7 @@ frame, rounded if necessary.  PIXELWISE non-nil means to return
 the coordinates in pixels where the values for RIGHT and BOTTOM
 are one more than the actual value of these edges.  Note that if
 ABSOLUTE is non-nil, PIXELWISE is implicitly non-nil too."
+  (declare (side-effect-free t))
   (let* ((window (window-normalize-window window body))
 	 (frame (window-frame window))
 	 (border-width (frame-internal-border-width frame))
@@ -3856,6 +3859,7 @@ ABSOLUTE is non-nil, PIXELWISE is implicitly non-nil too."
   "Return a list of the edge coordinates of WINDOW's body.
 The return value is that of `window-edges' called with argument
 BODY non-nil."
+  (declare (side-effect-free t))
   (window-edges window t))
 (defalias 'window-inside-edges 'window-body-edges)
 
@@ -3863,12 +3867,14 @@ BODY non-nil."
   "Return a list of the edge pixel coordinates of WINDOW.
 The return value is that of `window-edges' called with argument
 PIXELWISE non-nil."
+  (declare (side-effect-free t))
   (window-edges window nil nil t))
 
 (defun window-body-pixel-edges (&optional window)
   "Return a list of the edge pixel coordinates of WINDOW's body.
 The return value is that of `window-edges' called with arguments
 BODY and PIXELWISE non-nil."
+  (declare (side-effect-free t))
   (window-edges window t nil t))
 (defalias 'window-inside-pixel-edges 'window-body-pixel-edges)
 
@@ -3876,12 +3882,14 @@ BODY and PIXELWISE non-nil."
   "Return a list of the edge pixel coordinates of WINDOW.
 The return value is that of `window-edges' called with argument
 ABSOLUTE non-nil."
+  (declare (side-effect-free t))
   (window-edges window nil t t))
 
 (defun window-absolute-body-pixel-edges (&optional window)
   "Return a list of the edge pixel coordinates of WINDOW's text area.
 The return value is that of `window-edges' called with arguments
 BODY and ABSOLUTE non-nil."
+  (declare (side-effect-free t))
   (window-edges window t t t))
 (defalias 'window-inside-absolute-pixel-edges 'window-absolute-body-pixel-edges)
 
@@ -4091,6 +4099,7 @@ with a special meaning are:
 
 Anything else means consider all windows on the selected frame
 and no others."
+  (declare (side-effect-free error-free))
   (let ((base-window (selected-window)))
     (if (and nomini (eq base-window (minibuffer-window)))
 	(setq base-window (next-window base-window)))