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.

diff --git a/lisp/help-fns.el b/lisp/help-fns.el
index 182b22549b548518205264751ad63f12cbcc493d..a202c2d247e1cf8c1c984e3fcd604e1ce9877043 100644 (file)
--- 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