From 977046f8979b4f18f6be358a2d3d6aaefe5ffcd6 Mon Sep 17 00:00:00 2001
From: Andrea Corallo <akrl@sdf.org>
Date: Tue, 30 May 2023 15:30:11 +0200
Subject: [PATCH] Print know function types in C-h f

* lisp/emacs-lisp/subr-x.el (comp-known-type-specifiers): Move to
subr-x.el.
* lisp/help-fns.el (help-fns--signature): Make use of
`comp-known-type-specifiers' for printing more function types.
---
 lisp/emacs-lisp/comp.el   | 317 +-------------------------------------
 lisp/emacs-lisp/subr-x.el | 315 +++++++++++++++++++++++++++++++++++++
 lisp/help-fns.el          |  10 +-
 3 files changed, 322 insertions(+), 320 deletions(-)

diff --git a/lisp/emacs-lisp/comp.el b/lisp/emacs-lisp/comp.el
index ec51f805c2b..6d9270ba0b7 100644
--- a/lisp/emacs-lisp/comp.el
+++ b/lisp/emacs-lisp/comp.el
@@ -275,322 +275,7 @@ comp-post-pass-hooks
 Useful to hook into pass checkers.")
 
 ;; FIXME this probably should not be here but... good for now.
-(defconst comp-known-type-specifiers
-  `(
-    ;; Functions we can trust not to be or if redefined should expose
-    ;; the same type.  Vast majority of these is either pure or
-    ;; primitive, the original list is the union of pure +
-    ;; side-effect-free-fns + side-effect-and-error-free-fns:
-    (% (function ((or number marker) (or number marker)) number))
-    (* (function (&rest (or number marker)) number))
-    (+ (function (&rest (or number marker)) number))
-    (- (function (&rest (or number marker)) number))
-    (/ (function ((or number marker) &rest (or number marker)) number))
-    (/= (function ((or number marker) (or number marker)) boolean))
-    (1+ (function ((or number marker)) number))
-    (1- (function ((or number marker)) number))
-    (< (function ((or number marker) &rest (or number marker)) boolean))
-    (<= (function ((or number marker) &rest (or number marker)) boolean))
-    (= (function ((or number marker) &rest (or number marker)) boolean))
-    (> (function ((or number marker) &rest (or number marker)) boolean))
-    (>= (function ((or number marker) &rest (or number marker)) boolean))
-    (abs (function (number) number))
-    (acos (function (number) float))
-    (append (function (&rest t) t))
-    (aref (function (t fixnum) t))
-    (arrayp (function (t) boolean))
-    (ash (function (integer integer) integer))
-    (asin (function (number) float))
-    (assq (function (t list) list))
-    (atan (function (number &optional number) float))
-    (atom (function (t) boolean))
-    (bignump (function (t) boolean))
-    (bobp (function () boolean))
-    (bolp (function () boolean))
-    (bool-vector-count-consecutive (function (bool-vector boolean integer) fixnum))
-    (bool-vector-count-population (function (bool-vector) fixnum))
-    (bool-vector-not (function (bool-vector &optional bool-vector) bool-vector))
-    (bool-vector-p (function (t) boolean))
-    (bool-vector-subsetp (function (bool-vector bool-vector) boolean))
-    (boundp (function (symbol) boolean))
-    (buffer-end (function ((or number marker)) integer))
-    (buffer-file-name (function (&optional buffer) (or string null)))
-    (buffer-list (function (&optional frame) list))
-    (buffer-local-variables (function (&optional buffer) list))
-    (buffer-modified-p (function (&optional buffer) boolean))
-    (buffer-size (function (&optional buffer) integer))
-    (buffer-string (function () string))
-    (buffer-substring (function ((or integer marker) (or integer marker)) string))
-    (bufferp (function (t) boolean))
-    (byte-code-function-p (function (t) boolean))
-    (capitalize (function (or integer string) (or integer string)))
-    (car (function (list) t))
-    (car-less-than-car (function (list list) boolean))
-    (car-safe (function (t) t))
-    (case-table-p (function (t) boolean))
-    (cdr (function (list) t))
-    (cdr-safe (function (t) t))
-    (ceiling (function (number &optional number) integer))
-    (char-after (function (&optional (or marker integer)) (or fixnum null)))
-    (char-before (function (&optional (or marker integer)) (or fixnum null)))
-    (char-equal (function (integer integer) boolean))
-    (char-or-string-p (function (t) boolean))
-    (char-to-string (function (fixnum) string))
-    (char-width (function (fixnum) fixnum))
-    (characterp (function (t &optional t) boolean))
-    (charsetp (function (t) boolean))
-    (commandp (function (t &optional t) boolean))
-    (compare-strings (function (string (or integer marker null) (or integer marker null) string (or integer marker null) (or integer marker null) &optional t) (or (member t) fixnum)))
-    (concat (function (&rest sequence) string))
-    (cons (function (t t) cons))
-    (consp (function (t) boolean))
-    (coordinates-in-window-p (function (cons window) boolean))
-    (copy-alist (function (list) list))
-    (copy-marker (function (&optional (or integer marker) boolean) marker))
-    (copy-sequence (function (sequence) sequence))
-    (copysign (function (float float) float))
-    (cos (function (number) float))
-    (count-lines (function ((or integer marker) (or integer marker) &optional t) integer))
-    (current-buffer (function () buffer))
-    (current-global-map (function () cons))
-    (current-indentation (function () integer))
-    (current-local-map (function () (or cons null)))
-    (current-minor-mode-maps (function () (or cons null)))
-    (current-time (function () cons))
-    (current-time-string (function (&optional (or number list)
-                                              (or symbol string cons integer))
-                                   string))
-    (current-time-zone (function (&optional (or number list)
-                                            (or symbol string cons integer))
-                                 cons))
-    (custom-variable-p (function (symbol) boolean))
-    (decode-char (function (cons t) (or fixnum null)))
-    (decode-time (function (&optional (or number list)
-                                      (or symbol string cons integer)
-                                      symbol)
-                           cons))
-    (default-boundp (function (symbol) boolean))
-    (default-value (function (symbol) t))
-    (degrees-to-radians (function (number) float))
-    (documentation (function ((or function symbol subr) &optional t) (or null string)))
-    (downcase (function ((or fixnum string)) (or fixnum string)))
-    (elt (function (sequence integer) t))
-    (encode-char (function (fixnum symbol) (or fixnum null)))
-    (encode-time (function (cons &rest t) cons))
-    (eobp (function () boolean))
-    (eolp (function () boolean))
-    (eq (function (t t) boolean))
-    (eql (function (t t) boolean))
-    (equal (function (t t) boolean))
-    (error-message-string (function (list) string))
-    (eventp (function (t) boolean))
-    (exp (function (number) float))
-    (expt (function (number number) float))
-    (fboundp (function (symbol) boolean))
-    (fceiling (function (float) float))
-    (featurep (function (symbol &optional symbol) boolean))
-    (ffloor (function (float) float))
-    (file-directory-p (function (string) boolean))
-    (file-exists-p (function (string) boolean))
-    (file-locked-p (function (string) boolean))
-    (file-name-absolute-p (function (string) boolean))
-    (file-newer-than-file-p (function (string string) boolean))
-    (file-readable-p (function (string) boolean))
-    (file-symlink-p (function (string) boolean))
-    (file-writable-p (function (string) boolean))
-    (fixnump (function (t) boolean))
-    (float (function (number) float))
-    (float-time (function (&optional (or number list)) float))
-    (floatp (function (t) boolean))
-    (floor (function (number &optional number) integer))
-    (following-char (function () fixnum))
-    (format (function (string &rest t) string))
-    (format-time-string (function (string &optional (or number list)
-                                          (or symbol string cons integer))
-                                  string))
-    (frame-first-window (function ((or frame window)) window))
-    (frame-root-window (function (&optional (or frame window)) window))
-    (frame-selected-window (function (&optional (or frame window)) window))
-    (frame-visible-p (function (frame) boolean))
-    (framep (function (t) boolean))
-    (fround (function (float) float))
-    (ftruncate (function (float) float))
-    (get (function (symbol symbol) t))
-    (get-buffer (function ((or buffer string)) (or buffer null)))
-    (get-buffer-window (function (&optional (or buffer string) (or symbol (integer 0 0))) (or null window)))
-    (get-file-buffer (function (string) (or null buffer)))
-    (get-largest-window (function (&optional t t t) (or window null)))
-    (get-lru-window (function (&optional t t t) (or window null)))
-    (getenv (function (string &optional frame) (or null string)))
-    (gethash (function (t hash-table &optional t) t))
-    (hash-table-count (function (hash-table) integer))
-    (hash-table-p (function (t) boolean))
-    (identity (function (t) t))
-    (ignore (function (&rest t) null))
-    (int-to-string (function (number) string))
-    (integer-or-marker-p (function (t) boolean))
-    (integerp (function (t) boolean))
-    (interactive-p (function () boolean))
-    (intern-soft (function ((or string symbol) &optional vector) symbol))
-    (invocation-directory (function () string))
-    (invocation-name (function () string))
-    (isnan (function (float) boolean))
-    (keymap-parent (function (cons) (or cons null)))
-    (keymapp (function (t) boolean))
-    (keywordp (function (t) boolean))
-    (last (function (list &optional integer) list))
-    (lax-plist-get (function (list t) t))
-    (ldexp (function (number integer) float))
-    (length (function (t) (integer 0 *)))
-    (length< (function (sequence fixnum) boolean))
-    (length= (function (sequence fixnum) boolean))
-    (length> (function (sequence fixnum) boolean))
-    (line-beginning-position (function (&optional integer) integer))
-    (line-end-position (function (&optional integer) integer))
-    (list (function (&rest t) list))
-    (listp (function (t) boolean))
-    (local-variable-if-set-p (function (symbol &optional buffer) boolean))
-    (local-variable-p (function (symbol &optional buffer) boolean))
-    (locale-info (function ((member codeset days months paper)) (or null string)))
-    (log (function (number number) float))
-    (log10 (function (number) float))
-    (logand (function (&rest (or integer marker)) integer))
-    (logb (function (number) integer))
-    (logcount (function (integer) integer))
-    (logior (function (&rest (or integer marker)) integer))
-    (lognot (function (integer) integer))
-    (logxor (function (&rest (or integer marker)) integer))
-    ;; (lsh (function ((integer ,most-negative-fixnum *) integer) integer)) ?
-    (lsh (function (integer integer) integer))
-    (make-byte-code (function ((or fixnum list) string vector integer &optional string t &rest t) vector))
-    (make-list (function (integer t) list))
-    (make-marker (function () marker))
-    (make-string (function (integer fixnum &optional t) string))
-    (make-symbol (function (string) symbol))
-    (mark (function (&optional t) (or integer null)))
-    (mark-marker (function () marker))
-    (marker-buffer (function (marker) (or buffer null)))
-    (markerp (function (t) boolean))
-    (max (function ((or number marker) &rest (or number marker)) number))
-    (max-char (function (&optional t) fixnum))
-    (member (function (t list) list))
-    (memory-limit (function () integer))
-    (memq (function (t list) list))
-    (memql (function (t list) list))
-    (min (function ((or number marker) &rest (or number marker)) number))
-    (minibuffer-selected-window (function () (or window null)))
-    (minibuffer-window (function (&optional frame) window))
-    (mod (function ((or number marker) (or number marker)) (or (integer 0 *) (float 0 *))))
-    (mouse-movement-p (function (t) boolean))
-    (multibyte-char-to-unibyte (function (fixnum) fixnum))
-    (natnump (function (t) boolean))
-    (next-window (function (&optional window t t) window))
-    (nlistp (function (t) boolean))
-    (not (function (t) boolean))
-    (nth (function (integer list) t))
-    (nthcdr (function (integer t) t))
-    (null (function (t) boolean))
-    (number-or-marker-p (function (t) boolean))
-    (number-to-string (function (number) string))
-    (numberp (function (t) boolean))
-    (one-window-p (function (&optional t t) boolean))
-    (overlayp (function (t) boolean))
-    (parse-colon-path (function (string) cons))
-    (plist-get (function (list t &optional t) t))
-    (plist-member (function (list t &optional t) list))
-    (point (function () integer))
-    (point-marker (function () marker))
-    (point-max (function () integer))
-    (point-min (function () integer))
-    (preceding-char (function () fixnum))
-    (previous-window (function (&optional window t t) window))
-    (prin1-to-string (function (t &optional t t) string))
-    (processp (function (t) boolean))
-    (proper-list-p (function (t) boolean))
-    (propertize (function (string &rest t) string))
-    (radians-to-degrees (function (number) float))
-    (rassoc (function (t list) list))
-    (rassq (function (t list) list))
-    (read-from-string (function (string &optional integer integer) cons))
-    (recent-keys (function (&optional (or cons null)) vector))
-    (recursion-depth (function () integer))
-    (regexp-opt (function (list) string))
-    (regexp-quote (function (string) string))
-    (region-beginning (function () integer))
-    (region-end (function () integer))
-    (reverse (function (sequence) sequence))
-    (round (function (number &optional number) integer))
-    (safe-length (function (t) integer))
-    (selected-frame (function () frame))
-    (selected-window (function () window))
-    (sequencep (function (t) boolean))
-    (sin (function (number) float))
-    (sqrt (function (number) float))
-    (standard-case-table (function () char-table))
-    (standard-syntax-table (function () char-table))
-    (string (function (&rest fixnum) string))
-    (string-as-multibyte (function (string) string))
-    (string-as-unibyte (function (string) string))
-    (string-equal (function ((or string symbol) (or string symbol)) boolean))
-    (string-lessp (function ((or string symbol) (or string symbol)) boolean))
-    (string-make-multibyte (function (string) string))
-    (string-make-unibyte (function (string) string))
-    (string-search (function (string string &optional integer) (or integer null)))
-    (string-to-char (function (string) fixnum))
-    (string-to-multibyte (function (string) string))
-    (string-to-number (function (string &optional integer) number))
-    (string-to-syntax (function (string) (or cons null)))
-    (string< (function ((or string symbol) (or string symbol)) boolean))
-    (string= (function ((or string symbol) (or string symbol)) boolean))
-    (stringp (function (t) boolean))
-    (subrp (function (t) boolean))
-    (substring (function ((or string vector) &optional integer integer) (or string vector)))
-    (sxhash (function (t) integer))
-    (sxhash-eq (function (t) integer))
-    (sxhash-eql (function (t) integer))
-    (sxhash-equal (function (t) integer))
-    (symbol-function (function (symbol) t))
-    (symbol-name (function (symbol) string))
-    (symbol-plist (function (symbol) list))
-    (symbol-value (function (symbol) t))
-    (symbolp (function (t) boolean))
-    (syntax-table (function () char-table))
-    (syntax-table-p (function (t) boolean))
-    (tan (function (number) float))
-    (this-command-keys (function () string))
-    (this-command-keys-vector (function () vector))
-    (this-single-command-keys (function () vector))
-    (this-single-command-raw-keys (function () vector))
-    (time-convert (function ((or number list) &optional (or symbol integer))
-                            (or cons number)))
-    (truncate (function (number &optional number) integer))
-    (type-of (function (t) symbol))
-    (unibyte-char-to-multibyte (function (fixnum) fixnum)) ;; byte is fixnum
-    (upcase (function ((or fixnum string)) (or fixnum string)))
-    (user-full-name (function (&optional integer) (or string null)))
-    (user-login-name (function (&optional integer) (or string null)))
-    (user-original-login-name (function (&optional integer) (or string null)))
-    (user-real-login-name (function () string))
-    (user-real-uid (function () integer))
-    (user-uid (function () integer))
-    (vconcat (function (&rest sequence) vector))
-    (vector (function (&rest t) vector))
-    (vectorp (function (t) boolean))
-    (visible-frame-list (function () list))
-    (wholenump (function (t) boolean))
-    (window-configuration-p (function (t) boolean))
-    (window-live-p (function (t) boolean))
-    (window-valid-p (function (t) boolean))
-    (windowp (function (t) boolean))
-    (zerop (function (number) boolean))
-    ;; Type hints
-    (comp-hint-fixnum (function (t) fixnum))
-    (comp-hint-cons (function (t) cons))
-    ;; Non returning functions
-    (throw (function (t t) nil))
-    (error (function (string &rest t) nil))
-    (signal (function (symbol t) nil)))
-  "Alist used for type propagation.")
+
 
 (defconst comp-known-func-cstr-h
   (cl-loop
diff --git a/lisp/emacs-lisp/subr-x.el b/lisp/emacs-lisp/subr-x.el
index 9e906930b92..d9a32b950bb 100644
--- a/lisp/emacs-lisp/subr-x.el
+++ b/lisp/emacs-lisp/subr-x.el
@@ -37,6 +37,321 @@
 
 (eval-when-compile (require 'cl-lib))
 
+(defconst comp-known-type-specifiers
+  ;; Functions we can trust not to be redefined or if redefined should
+  ;; expose the same type.  The vast majority of these is either
+  ;; pure or primitive, the original list is the union of pure +
+  ;; side-effect-free-fns + side-effect-and-error-free-fns:
+  `((% (function ((or number marker) (or number marker)) number))
+    (* (function (&rest (or number marker)) number))
+    (+ (function (&rest (or number marker)) number))
+    (- (function (&rest (or number marker)) number))
+    (/ (function ((or number marker) &rest (or number marker)) number))
+    (/= (function ((or number marker) (or number marker)) boolean))
+    (1+ (function ((or number marker)) number))
+    (1- (function ((or number marker)) number))
+    (< (function ((or number marker) &rest (or number marker)) boolean))
+    (<= (function ((or number marker) &rest (or number marker)) boolean))
+    (= (function ((or number marker) &rest (or number marker)) boolean))
+    (> (function ((or number marker) &rest (or number marker)) boolean))
+    (>= (function ((or number marker) &rest (or number marker)) boolean))
+    (abs (function (number) number))
+    (acos (function (number) float))
+    (append (function (&rest t) t))
+    (aref (function (t fixnum) t))
+    (arrayp (function (t) boolean))
+    (ash (function (integer integer) integer))
+    (asin (function (number) float))
+    (assq (function (t list) list))
+    (atan (function (number &optional number) float))
+    (atom (function (t) boolean))
+    (bignump (function (t) boolean))
+    (bobp (function () boolean))
+    (bolp (function () boolean))
+    (bool-vector-count-consecutive (function (bool-vector boolean integer) fixnum))
+    (bool-vector-count-population (function (bool-vector) fixnum))
+    (bool-vector-not (function (bool-vector &optional bool-vector) bool-vector))
+    (bool-vector-p (function (t) boolean))
+    (bool-vector-subsetp (function (bool-vector bool-vector) boolean))
+    (boundp (function (symbol) boolean))
+    (buffer-end (function ((or number marker)) integer))
+    (buffer-file-name (function (&optional buffer) (or string null)))
+    (buffer-list (function (&optional frame) list))
+    (buffer-local-variables (function (&optional buffer) list))
+    (buffer-modified-p (function (&optional buffer) boolean))
+    (buffer-size (function (&optional buffer) integer))
+    (buffer-string (function () string))
+    (buffer-substring (function ((or integer marker) (or integer marker)) string))
+    (bufferp (function (t) boolean))
+    (byte-code-function-p (function (t) boolean))
+    (capitalize (function (or integer string) (or integer string)))
+    (car (function (list) t))
+    (car-less-than-car (function (list list) boolean))
+    (car-safe (function (t) t))
+    (case-table-p (function (t) boolean))
+    (cdr (function (list) t))
+    (cdr-safe (function (t) t))
+    (ceiling (function (number &optional number) integer))
+    (char-after (function (&optional (or marker integer)) (or fixnum null)))
+    (char-before (function (&optional (or marker integer)) (or fixnum null)))
+    (char-equal (function (integer integer) boolean))
+    (char-or-string-p (function (t) boolean))
+    (char-to-string (function (fixnum) string))
+    (char-width (function (fixnum) fixnum))
+    (characterp (function (t &optional t) boolean))
+    (charsetp (function (t) boolean))
+    (commandp (function (t &optional t) boolean))
+    (compare-strings (function (string (or integer marker null) (or integer marker null) string (or integer marker null) (or integer marker null) &optional t) (or (member t) fixnum)))
+    (concat (function (&rest sequence) string))
+    (cons (function (t t) cons))
+    (consp (function (t) boolean))
+    (coordinates-in-window-p (function (cons window) boolean))
+    (copy-alist (function (list) list))
+    (copy-marker (function (&optional (or integer marker) boolean) marker))
+    (copy-sequence (function (sequence) sequence))
+    (copysign (function (float float) float))
+    (cos (function (number) float))
+    (count-lines (function ((or integer marker) (or integer marker) &optional t) integer))
+    (current-buffer (function () buffer))
+    (current-global-map (function () cons))
+    (current-indentation (function () integer))
+    (current-local-map (function () (or cons null)))
+    (current-minor-mode-maps (function () (or cons null)))
+    (current-time (function () cons))
+    (current-time-string (function (&optional (or number list)
+                                              (or symbol string cons integer))
+                                   string))
+    (current-time-zone (function (&optional (or number list)
+                                            (or symbol string cons integer))
+                                 cons))
+    (custom-variable-p (function (symbol) boolean))
+    (decode-char (function (cons t) (or fixnum null)))
+    (decode-time (function (&optional (or number list)
+                                      (or symbol string cons integer)
+                                      symbol)
+                           cons))
+    (default-boundp (function (symbol) boolean))
+    (default-value (function (symbol) t))
+    (degrees-to-radians (function (number) float))
+    (documentation (function ((or function symbol subr) &optional t) (or null string)))
+    (downcase (function ((or fixnum string)) (or fixnum string)))
+    (elt (function (sequence integer) t))
+    (encode-char (function (fixnum symbol) (or fixnum null)))
+    (encode-time (function (cons &rest t) cons))
+    (eobp (function () boolean))
+    (eolp (function () boolean))
+    (eq (function (t t) boolean))
+    (eql (function (t t) boolean))
+    (equal (function (t t) boolean))
+    (error-message-string (function (list) string))
+    (eventp (function (t) boolean))
+    (exp (function (number) float))
+    (expt (function (number number) float))
+    (fboundp (function (symbol) boolean))
+    (fceiling (function (float) float))
+    (featurep (function (symbol &optional symbol) boolean))
+    (ffloor (function (float) float))
+    (file-directory-p (function (string) boolean))
+    (file-exists-p (function (string) boolean))
+    (file-locked-p (function (string) boolean))
+    (file-name-absolute-p (function (string) boolean))
+    (file-newer-than-file-p (function (string string) boolean))
+    (file-readable-p (function (string) boolean))
+    (file-symlink-p (function (string) boolean))
+    (file-writable-p (function (string) boolean))
+    (fixnump (function (t) boolean))
+    (float (function (number) float))
+    (float-time (function (&optional (or number list)) float))
+    (floatp (function (t) boolean))
+    (floor (function (number &optional number) integer))
+    (following-char (function () fixnum))
+    (format (function (string &rest t) string))
+    (format-time-string (function (string &optional (or number list)
+                                          (or symbol string cons integer))
+                                  string))
+    (frame-first-window (function ((or frame window)) window))
+    (frame-root-window (function (&optional (or frame window)) window))
+    (frame-selected-window (function (&optional (or frame window)) window))
+    (frame-visible-p (function (frame) boolean))
+    (framep (function (t) boolean))
+    (fround (function (float) float))
+    (ftruncate (function (float) float))
+    (get (function (symbol symbol) t))
+    (get-buffer (function ((or buffer string)) (or buffer null)))
+    (get-buffer-window (function (&optional (or buffer string) (or symbol (integer 0 0))) (or null window)))
+    (get-file-buffer (function (string) (or null buffer)))
+    (get-largest-window (function (&optional t t t) (or window null)))
+    (get-lru-window (function (&optional t t t) (or window null)))
+    (getenv (function (string &optional frame) (or null string)))
+    (gethash (function (t hash-table &optional t) t))
+    (hash-table-count (function (hash-table) integer))
+    (hash-table-p (function (t) boolean))
+    (identity (function (t) t))
+    (ignore (function (&rest t) null))
+    (int-to-string (function (number) string))
+    (integer-or-marker-p (function (t) boolean))
+    (integerp (function (t) boolean))
+    (interactive-p (function () boolean))
+    (intern-soft (function ((or string symbol) &optional vector) symbol))
+    (invocation-directory (function () string))
+    (invocation-name (function () string))
+    (isnan (function (float) boolean))
+    (keymap-parent (function (cons) (or cons null)))
+    (keymapp (function (t) boolean))
+    (keywordp (function (t) boolean))
+    (last (function (list &optional integer) list))
+    (lax-plist-get (function (list t) t))
+    (ldexp (function (number integer) float))
+    (length (function (t) (integer 0 *)))
+    (length< (function (sequence fixnum) boolean))
+    (length= (function (sequence fixnum) boolean))
+    (length> (function (sequence fixnum) boolean))
+    (line-beginning-position (function (&optional integer) integer))
+    (line-end-position (function (&optional integer) integer))
+    (list (function (&rest t) list))
+    (listp (function (t) boolean))
+    (local-variable-if-set-p (function (symbol &optional buffer) boolean))
+    (local-variable-p (function (symbol &optional buffer) boolean))
+    (locale-info (function ((member codeset days months paper)) (or null string)))
+    (log (function (number number) float))
+    (log10 (function (number) float))
+    (logand (function (&rest (or integer marker)) integer))
+    (logb (function (number) integer))
+    (logcount (function (integer) integer))
+    (logior (function (&rest (or integer marker)) integer))
+    (lognot (function (integer) integer))
+    (logxor (function (&rest (or integer marker)) integer))
+    ;; (lsh (function ((integer ,most-negative-fixnum *) integer) integer)) ?
+    (lsh (function (integer integer) integer))
+    (make-byte-code (function ((or fixnum list) string vector integer &optional string t &rest t) vector))
+    (make-list (function (integer t) list))
+    (make-marker (function () marker))
+    (make-string (function (integer fixnum &optional t) string))
+    (make-symbol (function (string) symbol))
+    (mark (function (&optional t) (or integer null)))
+    (mark-marker (function () marker))
+    (marker-buffer (function (marker) (or buffer null)))
+    (markerp (function (t) boolean))
+    (max (function ((or number marker) &rest (or number marker)) number))
+    (max-char (function (&optional t) fixnum))
+    (member (function (t list) list))
+    (memory-limit (function () integer))
+    (memq (function (t list) list))
+    (memql (function (t list) list))
+    (min (function ((or number marker) &rest (or number marker)) number))
+    (minibuffer-selected-window (function () (or window null)))
+    (minibuffer-window (function (&optional frame) window))
+    (mod (function ((or number marker) (or number marker)) (or (integer 0 *) (float 0 *))))
+    (mouse-movement-p (function (t) boolean))
+    (multibyte-char-to-unibyte (function (fixnum) fixnum))
+    (natnump (function (t) boolean))
+    (next-window (function (&optional window t t) window))
+    (nlistp (function (t) boolean))
+    (not (function (t) boolean))
+    (nth (function (integer list) t))
+    (nthcdr (function (integer t) t))
+    (null (function (t) boolean))
+    (number-or-marker-p (function (t) boolean))
+    (number-to-string (function (number) string))
+    (numberp (function (t) boolean))
+    (one-window-p (function (&optional t t) boolean))
+    (overlayp (function (t) boolean))
+    (parse-colon-path (function (string) cons))
+    (plist-get (function (list t &optional t) t))
+    (plist-member (function (list t &optional t) list))
+    (point (function () integer))
+    (point-marker (function () marker))
+    (point-max (function () integer))
+    (point-min (function () integer))
+    (preceding-char (function () fixnum))
+    (previous-window (function (&optional window t t) window))
+    (prin1-to-string (function (t &optional t t) string))
+    (processp (function (t) boolean))
+    (proper-list-p (function (t) boolean))
+    (propertize (function (string &rest t) string))
+    (radians-to-degrees (function (number) float))
+    (rassoc (function (t list) list))
+    (rassq (function (t list) list))
+    (read-from-string (function (string &optional integer integer) cons))
+    (recent-keys (function (&optional (or cons null)) vector))
+    (recursion-depth (function () integer))
+    (regexp-opt (function (list) string))
+    (regexp-quote (function (string) string))
+    (region-beginning (function () integer))
+    (region-end (function () integer))
+    (reverse (function (sequence) sequence))
+    (round (function (number &optional number) integer))
+    (safe-length (function (t) integer))
+    (selected-frame (function () frame))
+    (selected-window (function () window))
+    (sequencep (function (t) boolean))
+    (sin (function (number) float))
+    (sqrt (function (number) float))
+    (standard-case-table (function () char-table))
+    (standard-syntax-table (function () char-table))
+    (string (function (&rest fixnum) string))
+    (string-as-multibyte (function (string) string))
+    (string-as-unibyte (function (string) string))
+    (string-equal (function ((or string symbol) (or string symbol)) boolean))
+    (string-lessp (function ((or string symbol) (or string symbol)) boolean))
+    (string-make-multibyte (function (string) string))
+    (string-make-unibyte (function (string) string))
+    (string-search (function (string string &optional integer) (or integer null)))
+    (string-to-char (function (string) fixnum))
+    (string-to-multibyte (function (string) string))
+    (string-to-number (function (string &optional integer) number))
+    (string-to-syntax (function (string) (or cons null)))
+    (string< (function ((or string symbol) (or string symbol)) boolean))
+    (string= (function ((or string symbol) (or string symbol)) boolean))
+    (stringp (function (t) boolean))
+    (subrp (function (t) boolean))
+    (substring (function ((or string vector) &optional integer integer) (or string vector)))
+    (sxhash (function (t) integer))
+    (sxhash-eq (function (t) integer))
+    (sxhash-eql (function (t) integer))
+    (sxhash-equal (function (t) integer))
+    (symbol-function (function (symbol) t))
+    (symbol-name (function (symbol) string))
+    (symbol-plist (function (symbol) list))
+    (symbol-value (function (symbol) t))
+    (symbolp (function (t) boolean))
+    (syntax-table (function () char-table))
+    (syntax-table-p (function (t) boolean))
+    (tan (function (number) float))
+    (this-command-keys (function () string))
+    (this-command-keys-vector (function () vector))
+    (this-single-command-keys (function () vector))
+    (this-single-command-raw-keys (function () vector))
+    (time-convert (function ((or number list) &optional (or symbol integer))
+                            (or cons number)))
+    (truncate (function (number &optional number) integer))
+    (type-of (function (t) symbol))
+    (unibyte-char-to-multibyte (function (fixnum) fixnum)) ;; byte is fixnum
+    (upcase (function ((or fixnum string)) (or fixnum string)))
+    (user-full-name (function (&optional integer) (or string null)))
+    (user-login-name (function (&optional integer) (or string null)))
+    (user-original-login-name (function (&optional integer) (or string null)))
+    (user-real-login-name (function () string))
+    (user-real-uid (function () integer))
+    (user-uid (function () integer))
+    (vconcat (function (&rest sequence) vector))
+    (vector (function (&rest t) vector))
+    (vectorp (function (t) boolean))
+    (visible-frame-list (function () list))
+    (wholenump (function (t) boolean))
+    (window-configuration-p (function (t) boolean))
+    (window-live-p (function (t) boolean))
+    (window-valid-p (function (t) boolean))
+    (windowp (function (t) boolean))
+    (zerop (function (number) boolean))
+    ;; Type hints
+    (comp-hint-fixnum (function (t) fixnum))
+    (comp-hint-cons (function (t) cons))
+    ;; Non returning functions
+    (throw (function (t t) nil))
+    (error (function (string &rest t) nil))
+    (signal (function (symbol t) nil)))
+  "Alist used for type propagation.")
 
 (defmacro internal--thread-argument (first? &rest forms)
   "Internal implementation for `thread-first' and `thread-last'.
diff --git a/lisp/help-fns.el b/lisp/help-fns.el
index c4e09e48bea..af1c37f2d86 100644
--- a/lisp/help-fns.el
+++ b/lisp/help-fns.el
@@ -711,10 +711,12 @@ help-fns--signature
           (unless (and (symbolp function)
                        (get function 'reader-construct))
             (insert high-usage "\n")
-            (when (and (featurep 'native-compile)
-                       (subr-native-elisp-p (symbol-function function))
-                       (subr-type (symbol-function function)))
-              (insert (format "\nInferred type: %s\n" (subr-type (symbol-function function))))))
+            (if-let ((entry (assoc function comp-known-type-specifiers)))
+                (insert (format "\nType: %s\n" (car (cdr entry))))
+              (when (and (featurep 'native-compile)
+                         (subr-native-elisp-p (symbol-function function))
+                         (subr-type (symbol-function function)))
+                (insert (format "\nInferred type: %s\n" (subr-type (symbol-function function)))))))
           (fill-region fill-begin (point))
           high-doc)))))
 
-- 
2.25.1