master 9d3fb195af4 2/2: Fix argument name highlighting in 'describe-function' output

[Eshel Yaron]

branch: master
commit 9d3fb195af40f26a3751c368af55677667af3eba
Author: Eshel Yaron <me@eshelyaron.com>
Commit: Eshel Yaron <me@eshelyaron.com>

    Fix argument name highlighting in 'describe-function' output
    
    This fixes a regression introduced in
    dd38097f0b9458eea882043fa06b27248e505b22, which prevented proper
    argument name highlighting in function docstrings in the output
    buffer of 'describe-function'.
    
    * lisp/help-fns.el (help-do-arg-highlight): New optional arg
    that says if we're highlighting arguments in the usage string or
    in the docstring.  Tweak generated regex to only expect argument
    name to be preceded by function name in usage string.
    (help-highlight-arguments): Use new argument for usage string.
---
 lisp/help-fns.el | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/lisp/help-fns.el b/lisp/help-fns.el
index 182b22549b5..a202c2d247e 100644
--- a/lisp/help-fns.el
+++ b/lisp/help-fns.el
@@ -362,14 +362,17 @@ if the variable `help-downcase-arguments' is non-nil."
   (propertize (if help-downcase-arguments (downcase arg) arg)
              'face 'help-argument-name))
 
-(defun help-do-arg-highlight (doc args)
+(defun help-do-arg-highlight (doc args &optional usage-p)
   (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table)
     (modify-syntax-entry ?\- "w")
     (dolist (arg args)
       (setq doc (replace-regexp-in-string
                  ;; This is heuristic, but covers all common cases
                  ;; except ARG1-ARG2
-                 (concat "([^ ]+ .*"             ; skip function name
+                 (concat (when usage-p
+                           ;; Skip function name in usage string
+                           ;; (Bug#65580).
+                           "([^ ]+ .*")
                          "\\<"                   ; beginning of word
                          "\\(?:[a-z-]*-\\)?"     ; for xxx-ARG
                          "\\("
@@ -404,7 +407,7 @@ if the variable `help-downcase-arguments' is non-nil."
               (search-backward "(")
               (goto-char (scan-sexps (point) 1)))))
         ;; Highlight arguments in the USAGE string
-        (setq usage (help-do-arg-highlight (buffer-string) args))
+        (setq usage (help-do-arg-highlight (buffer-string) args t))
         ;; Highlight arguments in the DOC string
         (setq doc (and doc (help-do-arg-highlight doc args))))))
   ;; Return value is like the one from help-split-fundoc, but highlighted