Make VC-Dir's 'd' able to delete unregistered files

* lisp/vc/vc.el (vc-delete-file): Simplify.
* lisp/vc/vc-dir.el (vc-dir-delete-file): Handle deleting
unregistered files, too.
(vc-dir-menu-map, vc-dir-mode-map): Replace bindings for
vc-dir-clean-files with ones for vc-dir-delete-file.
* doc/emacs/maintaining.texi (VC Directory Commands):
* etc/NEWS: Document the bindings change.

doc/emacs/maintaining.texi

@@ -1707,9 +1707,8 @@ Branches}.
 
 @item d
 Delete the marked files, or the current file if no marks
-(@code{vc-dir-clean-delete)}.  The files will not be marked as
-deleted in the version control system, so this function is mostly
-useful for unregistered files.
+(@code{vc-dir-delete-file)}.  If the files are registered, they will be
+marked as deleted in the version control system.
 @end table
 
 @cindex stashes in version control

etc/NEWS

@@ -2501,6 +2501,13 @@ Previously, Emacs would simply refuse to make any changes.
 You can customize 'vc-dir-allow-mass-mark-changes' to restore the old
 behavior or dispense with the prompting.
 
++++
+*** VC Directory's 'd' command can now delete unregistered files too.
+Previously, this command could only delete registered files.
+To restore the old, more limited behavior, you can do
+
+    (keymap-set vc-dir-mode-map "d" #'vc-dir-clean-files)
+
 ---
 *** New VC Directory bindings 'z d' and 'D' to delete Git stashes.
 These correspond to the existing 'z p' to pop a stash and 'P' to pop the

lisp/vc/vc-dir.el

@@ -279,8 +279,8 @@ That is, refreshing the VC-Dir buffer also hides `up-to-date' and
       '(menu-item "Open File" vc-dir-find-file
 		  :help "Find the file on the current line"))
     (define-key map [delete]
-      '(menu-item "Delete" vc-dir-clean-files
-		  :help "Delete the unregistered marked files"))
+      '(menu-item "Delete" vc-dir-delete-files
+		  :help "Delete marked files"))
     (define-key map [sepvcdet] '("--"))
     ;; FIXME: This needs a key binding.  And maybe a better name
     ;; ("Insert" like PCL-CVS uses does not sound that great either)...
@@ -362,7 +362,7 @@ That is, refreshing the VC-Dir buffer also hides `up-to-date' and
     ;;                                     bound by `special-mode'.
     ;; Marking.
     (define-key map "m" #'vc-dir-mark)
-    (define-key map "d" #'vc-dir-clean-files)
+    (define-key map "d" #'vc-dir-delete-file)
     (define-key map "M" #'vc-dir-mark-all-files)
     (define-key map "u" #'vc-dir-unmark)
     (define-key map "U" #'vc-dir-unmark-all-files)
@@ -1028,8 +1028,7 @@ tracked by a VCS."
 The files will also be marked as deleted in the version control
 system."
   (interactive)
-  (mapc #'vc-delete-file (or (vc-dir-marked-files)
-                            (list (vc-dir-current-file)))))
+  (vc-delete-file (or (vc-dir-marked-files) (vc-dir-current-file))))
 
 (defun vc-dir-find-file ()
   "Find the file on the current line."

lisp/vc/vc.el

@@ -4492,10 +4492,8 @@ file names."
   (dolist (file file-or-files)
     (let ((buf (get-file-buffer file))
           (backend (vc-backend file)))
-      (unless backend
-        (error "File %s is not under version control"
-               (file-name-nondirectory file)))
-      (unless (vc-find-backend-function backend 'delete-file)
+      (unless (or (not backend)
+                  (vc-find-backend-function backend 'delete-file))
         (error "Deleting files under %s is not supported in VC" backend))
       (when (and buf (buffer-modified-p buf))
         (error "Please save or undo your changes before deleting %s" file))
@@ -4518,11 +4516,13 @@ file names."
         (with-current-buffer (or buf (find-file-noselect file))
           (let ((backup-inhibited nil))
 	    (backup-buffer))))
-      ;; Bind `default-directory' so that the command that the backend
-      ;; runs to remove the file is invoked in the correct context.
-      (let ((default-directory (file-name-directory file)))
-        (vc-call-backend backend 'delete-file file))
-      ;; If the backend hasn't deleted the file itself, let's do it for him.
+      (when backend
+        ;; Bind `default-directory' so that the command that the backend
+        ;; runs to remove the file is invoked in the correct context.
+        (let ((default-directory (file-name-directory file)))
+          (vc-call-backend backend 'delete-file file)))
+      ;; For the case of unregistered files, or if the backend didn't
+      ;; actually delete the file.
       (when (file-exists-p file) (delete-file file))
       ;; Forget what VC knew about the file.
       (vc-file-clearprops file)